Preimplantation embryo development in vitro: cooperative interactions among embryos and role of growth factors.

PubMed Central

Paria, B C; Dey, S K

1990-01-01

We have established a model that shows cooperative interaction among preimplantation embryos and the role of growth factors on their development and growth. Two-cell mouse embryos cultured singly in 25-microliters microdrops had inferior development to blastocysts and lower cell numbers per blastocyst compared with those cultured in groups of 5 or 10. The inferior development of singly cultured embryos was markedly improved by addition of epidermal growth factor (EGF) or transforming growth factor alpha or beta 1 (TGF-alpha or TGF-beta 1) to the culture medium. The stage of embryonic development, primarily affected by these treatments, was between eight-cell/morula and blastocyst. Furthermore, blastocysts developed from eight-cell embryos cultured in groups or singly in the presence of EGF showed a higher incidence of zona hatching compared with those cultured singly in the absence of EGF. Detection of EGF receptors on the embryonic cell surface at eight-cell/morula and blastocyst stages suggests beneficial effects of EGF or TGF-alpha on preimplantation embryo development and blastocyst functions. Insulin-like growth factor I (IGF-I) had no influence on embryo development. To further document the cooperative interactions among embryos, the volume of the culture medium was doubled to 50 microliters. This increase in culture volume was even more detrimental to the development of singly cultured embryos. However, this detrimental effect was significantly reversed by EGF and reversed even more markedly by a combination of EGF and TGF-beta 1 but not by TGF-beta 1 alone. Although TGF-beta 1 plus IGF-I caused a modest improvement of embryo development, the response was not as great as shown by EGF alone. Furthermore, IGF-I had no additive effect on EGF-induced embryonic development. The study presents clear evidence that specific growth factors of embryonic and/or reproductive tract origin participate in preimplantation embryo development and blastocyst functions in an autocrine/paracrine manner. Images PMID:2352946

Modeling to predict growth/no growth boundaries and kinetic behavior of Salmonella on cutting board surfaces.

PubMed

Yoon, Hyunjoo; Lee, Joo-Yeon; Suk, Hee-Jin; Lee, Sunah; Lee, Heeyoung; Lee, Soomin; Yoon, Yohan

2012-12-01

This study developed models to predict the growth probabilities and kinetic behavior of Salmonella enterica strains on cutting boards. Polyethylene coupons (3 by 5 cm) were rubbed with pork belly, and pork purge was then sprayed on the coupon surface, followed by inoculation of a five-strain Salmonella mixture onto the surface of the coupons. These coupons were stored at 13 to 35°C for 12 h, and total bacterial and Salmonella cell counts were enumerated on tryptic soy agar and xylose lysine deoxycholate (XLD) agar, respectively, every 2 h, which produced 56 combinations. The combinations that had growth of ≥0.5 log CFU/cm(2) of Salmonella bacteria recovered on XLD agar were given the value 1 (growth), and the combinations that had growth of <0.5 log CFU/cm(2) were assigned the value 0 (no growth). These growth response data from XLD agar were analyzed by logistic regression for producing growth/no growth interfaces of Salmonella bacteria. In addition, a linear model was fitted to the Salmonella cell counts to calculate the growth rate (log CFU per square centimeter per hour) and initial cell count (log CFU per square centimeter), following secondary modeling with the square root model. All of the models developed were validated with observed data, which were not used for model development. Growth of total bacteria and Salmonella cells was observed at 28, 30, 33, and 35°C, but there was no growth detected below 20°C within the time frame investigated. Moreover, various indices indicated that the performance of the developed models was acceptable. The results suggest that the models developed in this study may be useful in predicting the growth/no growth interface and kinetic behavior of Salmonella bacteria on polyethylene cutting boards.

Stochastic cellular automata model of neurosphere growth: Roles of proliferative potential, contact inhibition, cell death, and phagocytosis.

PubMed

Sipahi, Rifat; Zupanc, Günther K H

2018-05-14

Neural stem and progenitor cells isolated from the central nervous system form, under specific culture conditions, clonal cell clusters known as neurospheres. The neurosphere assay has proven to be a powerful in vitro system to study the behavior of such cells and the development of their progeny. However, the theory of neurosphere growth has remained poorly understood. To overcome this limitation, we have, in the present paper, developed a cellular automata model, with which we examined the effects of proliferative potential, contact inhibition, cell death, and clearance of dead cells on growth rate, final size, and composition of neurospheres. Simulations based on this model indicated that the proliferative potential of the founder cell and its progenitors has a major influence on neurosphere size. On the other hand, contact inhibition of proliferation limits the final size, and reduces the growth rate, of neurospheres. The effect of this inhibition is particularly dramatic when a stem cell becomes encapsulated by differentiated or other non-proliferating cells, thereby suppressing any further mitotic division - despite the existing proliferative potential of the stem cell. Conversely, clearance of dead cells through phagocytosis is predicted to accelerate growth by reducing contact inhibition. A surprising prediction derived from our model is that cell death, while resulting in a decrease in growth rate and final size of neurospheres, increases the degree of differentiation of neurosphere cells. It is likely that the cellular automata model developed as part of the present investigation is applicable to the study of tissue growth in a wide range of systems. Copyright © 2018 Elsevier Ltd. All rights reserved.

Sonic hedgehog controls growth of external genitalia by regulating cell cycle kinetics

PubMed Central

Seifert, Ashley W.; Zheng, Zhengui; Ormerod, Brandi K.; Cohn, Martin J.

2010-01-01

During embryonic development, cells are instructed which position to occupy, they interpret these cues as differentiation programmes, and expand these patterns by growth. Sonic hedgehog (Shh) specifies positional identity in many organs; however, its role in growth is not well understood. In this study, we show that inactivation of Shh in external genitalia extends the cell cycle from 8.5 to 14.4 h, and genital growth is reduced by ∼75%. Transient Shh signalling establishes pattern in the genital tubercle; however, transcriptional levels of G1 cell cycle regulators are reduced. Consequently, G1 length is extended, leading to fewer progenitor cells entering S-phase. Cell cycle genes responded similarly to Shh inactivation in genitalia and limbs, suggesting that Shh may regulate growth by similar mechanisms in different organ systems. The finding that Shh regulates cell number by controlling the length of specific cell cycle phases identifies a novel mechanism by which Shh elaborates pattern during appendage development. PMID:20975695

Accounting for inherent variability of growth in microbial risk assessment.

PubMed

Marks, H M; Coleman, M E

2005-04-15

Risk assessments of pathogens need to account for the growth of small number of cells under varying conditions. In order to determine the possible risks that occur when there are small numbers of cells, stochastic models of growth are needed that would capture the distribution of the number of cells over replicate trials of the same scenario or environmental conditions. This paper provides a simple stochastic growth model, accounting only for inherent cell-growth variability, assuming constant growth kinetic parameters, for an initial, small, numbers of cells assumed to be transforming from a stationary to an exponential phase. Two, basic, microbial sets of assumptions are considered: serial, where it is assume that cells transform through a lag phase before entering the exponential phase of growth; and parallel, where it is assumed that lag and exponential phases develop in parallel. The model is based on, first determining the distribution of the time when growth commences, and then modelling the conditional distribution of the number of cells. For the latter distribution, it is found that a Weibull distribution provides a simple approximation to the conditional distribution of the relative growth, so that the model developed in this paper can be easily implemented in risk assessments using commercial software packages.

Understanding the role of growth factors in embryonic development: insights from the lens

PubMed Central

Lovicu, F. J.; McAvoy, J. W.; de Iongh, R. U.

2011-01-01

Growth factors play key roles in influencing cell fate and behaviour during development. The epithelial cells and fibre cells that arise from the lens vesicle during lens morphogenesis are bathed by aqueous and vitreous, respectively. Vitreous has been shown to generate a high level of fibroblast growth factor (FGF) signalling that is required for secondary lens fibre differentiation. However, studies also show that FGF signalling is not sufficient and roles have been identified for transforming growth factor-β and Wnt/Frizzled families in regulating aspects of fibre differentiation. In the case of the epithelium, key roles for Wnt/β-catenin and Notch signalling have been demonstrated in embryonic development, but it is not known if other factors are required for its formation and maintenance. This review provides an overview of current knowledge about growth factor regulation of differentiation and maintenance of lens cells. It also highlights areas that warrant future study. PMID:21402581

A mathematical model and computational framework for three-dimensional chondrocyte cell growth in a porous tissue scaffold placed inside a bi-directional flow perfusion bioreactor.

PubMed

Shakhawath Hossain, Md; Bergstrom, D J; Chen, X B

2015-12-01

The in vitro chondrocyte cell culture for cartilage tissue regeneration in a perfusion bioreactor is a complex process. Mathematical modeling and computational simulation can provide important insights into the culture process, which would be helpful for selecting culture conditions to improve the quality of the developed tissue constructs. However, simulation of the cell culture process is a challenging task due to the complicated interaction between the cells and local fluid flow and nutrient transport inside the complex porous scaffolds. In this study, a mathematical model and computational framework has been developed to simulate the three-dimensional (3D) cell growth in a porous scaffold placed inside a bi-directional flow perfusion bioreactor. The model was developed by taking into account the two-way coupling between the cell growth and local flow field and associated glucose concentration, and then used to perform a resolved-scale simulation based on the lattice Boltzmann method (LBM). The simulation predicts the local shear stress, glucose concentration, and 3D cell growth inside the porous scaffold for a period of 30 days of cell culture. The predicted cell growth rate was in good overall agreement with the experimental results available in the literature. This study demonstrates that the bi-directional flow perfusion culture system can enhance the homogeneity of the cell growth inside the scaffold. The model and computational framework developed is capable of providing significant insight into the culture process, thus providing a powerful tool for the design and optimization of the cell culture process. © 2015 Wiley Periodicals, Inc.

The growth and differentiation of transitional epithelium in vitro.

PubMed

Chlapowski, F J; Haynes, L

1979-12-01

The development of rat transitional epithelial cells grown on conventional non-permeable surfaces was compared with development on permeable collagen supports. On glass or plastic surfaces, cells grew as expanding nomolayer sheets. Once confluent, growth continued with a bilayer being formed in most areas and apical cells being continuously sloughed off. Although most cells were interconnected by desmosomes, and junctional complexes were formed, no other indications of differentiation were observed. After 2-3 wk of growth, division stopped and cel death ensued. In contrast, single-cell suspensions plated on collagen-coated nylon disks reassociated into multicellular islands and commenced growth. Mitoses were confined to the basal cells in contact with the permeable substrate. The islands developed into epithelial trilayers, tapering to monolayers along spreading edges. Once the islands were confluent, stratification was completed and appeared similar to that observed in vivo. Germinal cells formed a basal lamina, and the upper layer was composed of large, flattened cells with an unusually thick asymmetrical plasma membrane on the apical surface. Electron microscopic and radioactive tracers demonstrated "leaky" zonulae occludentes with a restricted permeability to small molecules. The movement of urea was retarded in comparison to water. Unlike the slow turnover of adult epithelium in vivo, maturation and sloughing of apical cells were measurable. Transfer of cells could be effected and growth maintained for up to 4 mo. These results may indicate the necessity of a nutrient-permeable growth surface for the polarized differentiation of adult transitional epithelium.

The growth and differentiation of transitional epithelium in vitro

PubMed Central

1979-01-01

The development of rat transitional epithelial cells grown on conventional non-permeable surfaces was compared with development on permeable collagen supports. On glass or plastic surfaces, cells grew as expanding nomolayer sheets. Once confluent, growth continued with a bilayer being formed in most areas and apical cells being continuously sloughed off. Although most cells were interconnected by desmosomes, and junctional complexes were formed, no other indications of differentiation were observed. After 2-3 wk of growth, division stopped and cel death ensued. In contrast, single-cell suspensions plated on collagen-coated nylon disks reassociated into multicellular islands and commenced growth. Mitoses were confined to the basal cells in contact with the permeable substrate. The islands developed into epithelial trilayers, tapering to monolayers along spreading edges. Once the islands were confluent, stratification was completed and appeared similar to that observed in vivo. Germinal cells formed a basal lamina, and the upper layer was composed of large, flattened cells with an unusually thick asymmetrical plasma membrane on the apical surface. Electron microscopic and radioactive tracers demonstrated "leaky" zonulae occludentes with a restricted permeability to small molecules. The movement of urea was retarded in comparison to water. Unlike the slow turnover of adult epithelium in vivo, maturation and sloughing of apical cells were measurable. Transfer of cells could be effected and growth maintained for up to 4 mo. These results may indicate the necessity of a nutrient-permeable growth surface for the polarized differentiation of adult transitional epithelium. PMID:574872

Polarity, cell division, and out-of-equilibrium dynamics control the growth of epithelial structures

PubMed Central

Cerruti, Benedetta; Puliafito, Alberto; Shewan, Annette M.; Yu, Wei; Combes, Alexander N.; Little, Melissa H.; Chianale, Federica; Primo, Luca; Serini, Guido; Mostov, Keith E.; Celani, Antonio

2013-01-01

The growth of a well-formed epithelial structure is governed by mechanical constraints, cellular apico-basal polarity, and spatially controlled cell division. Here we compared the predictions of a mathematical model of epithelial growth with the morphological analysis of 3D epithelial structures. In both in vitro cyst models and in developing epithelial structures in vivo, epithelial growth could take place close to or far from mechanical equilibrium, and was determined by the hierarchy of time-scales of cell division, cell–cell rearrangements, and lumen dynamics. Equilibrium properties could be inferred by the analysis of cell–cell contact topologies, and the nonequilibrium phenotype was altered by inhibiting ROCK activity. The occurrence of an aberrant multilumen phenotype was linked to fast nonequilibrium growth, even when geometric control of cell division was correctly enforced. We predicted and verified experimentally that slowing down cell division partially rescued a multilumen phenotype induced by altered polarity. These results improve our understanding of the development of epithelial organs and, ultimately, of carcinogenesis. PMID:24145168

Deregulation of cell growth and malignant transformation.

PubMed

Sulić, Sanda; Panić, Linda; Dikić, Ivan; Volarević, Sinisa

2005-08-01

Cell growth and cell division are fundamental aspects of cell behavior in all organisms. Recent insights from many model organisms have shed light on the molecular mechanisms that control cell growth and cell division. A significant body of evidence has now been accumulated, showing a direct link between deregulation of components of cell cycle machinery and cancer. In addition, defects in one or more steps that control growth are important for malignant transformation, as many tumor suppressors and proto-oncogenes have been found to regulate cell growth. The importance of cell growth in tumor development is further supported by the discovery that rapamycin, an effective anticancer drug, inhibits a key regulator of protein synthetic machinery and cell growth, mammalian target of rapamycin (mTOR). In most cases, cell growth and cell division are coupled, thereby maintaining cell size within physiological limits. We believe that, in a long-term perspective, understanding how these two processes are coordinated in vivo and how their interplay is deregulated in a number of diseases, including cancer, may have a direct impact on the efficiency of modern therapeutics.

JNK-associated scattered growth of YD-10B oral squamous carcinoma cells while maintaining the epithelial phenotype

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Gayoung; Kim, Hyun-Man

Cell scattering of epithelial carcinoma cancer cells is one of the critical event in tumorigenesis. Cells losing epithelial cohesion detach from aggregated epithelial cell masses and may migrate to fatal organs through metastasis. The present study investigated the molecular mechanism by which squamous cell carcinoma cells grow scattered at the early phase of transformation while maintaining the epithelial phenotype. We studied YD-10B cells, which are established from human oral squamous cell carcinoma, because the cells grow scattered without the development of E-cadherin junctions (ECJs) under routine culture conditions despite the high expression of functional E-cadherin. The functionality of their E-cadherinmore » was demonstrated in that YD-10B cells developed ECJs, transiently or persistently, when they were cultured on substrates coated with a low amount of fibronectin or to confluence. The phosphorylation of JNK was up-regulated in YD-10B cells compared with that in human normal oral keratinocyte cells or human squamous cell carcinoma cells, which grew aggregated along with well-organized ECJs. The suppression of JNK activity induced the aggregated growth of YD-10B cells concomitant with the development of ECJs. These results indicate for the first time that inherently up-regulated JNK activity induces the scattered growth of the oral squamous cell carcinoma cells through down-regulating the development of ECJ despite the expression of functional E-cadherin, a hallmark of the epithelial phenotype. - Highlights: • JNK dissociates YD-10B oral squamous cell carcinoma cells. • JNK suppresses the development of E-cadherin junctions of oral carcinoma cells. • Suppression of JNK activity reverses the scattered growth of oral carcinoma cells.« less

EGF-mediated EGFR/ERK signaling pathway promotes germinative cell proliferation in Echinococcus multilocularis that contributes to larval growth and development

PubMed Central

Li, Xiu; Dai, Mengya; Wu, Jianjian; Guo, Xinrui; Tian, Huimin; Heng, Zhijie; Lu, Ying; Chai, Xiaoli

2017-01-01

Background Larvae of the tapeworm E. multilocularis cause alveolar echinococcosis (AE), one of the most lethal helminthic infections in humans. A population of stem cell-like cells, the germinative cells, is considered to drive the larval growth and development within the host. The molecular mechanisms controlling the behavior of germinative cells are largely unknown. Methodology/Principal findings Using in vitro cultivation systems we show here that the EGFR/ERK signaling in the parasite can promote germinative cell proliferation in response to addition of human EGF, resulting in stimulated growth and development of the metacestode larvae. Inhibition of the signaling by either the EGFR inhibitors CI-1033 and BIBW2992 or the MEK/ERK inhibitor U0126 impairs germinative cell proliferation and larval growth. Conclusions/Significance These data demonstrate the contribution of EGF-mediated EGFR/ERK signaling to the regulation of germinative cells in E. multilocularis, and suggest the EGFR/ERK signaling as a potential therapeutic target for AE and perhaps other human cestodiasis. PMID:28241017

Enhanced Growth and Hepatic Differentiation of Fetal Liver Epithelial Cells through Combinational and Temporal Adjustment of Soluble Factors

PubMed Central

Qian, Lichuan; Krause, Diane S.; Saltzman, W. Mark

2012-01-01

Fetal liver epithelial cells (FLEC) are valuable for liver cell therapy and tissue engineering, but methods for culture and characterization of these cells are not well developed. This work explores the influence of multiple soluble factors on FLEC, with the long-term goal of developing an optimal culture system to generate functional liver tissue. Our comparative analysis suggests hepatocyte growth factor (HGF) is required throughout the culture period. In the presence of HGF, addition of oncostatin M (OSM) at culture initiation results in concurrent growth and maturation, while constant presence of protective agents like ascorbic acid enhances cell survival. Study observations led to the development of a culture medium that provided optimal growth and hepatic differentiation conditions. FLEC expansion was observed to be ~2 fold of that under standard conditions, albumin secretion rate was 2 – 3 times greater than maximal values obtained with other media, and the highest level of glycogen accumulation among all conditions was observed with the developed medium. Our findings serve to advance culture methods for liver progenitors in cell therapy and tissue engineering applications. PMID:21922669

Neurodevelopmental effects of insulin-like growth factor signaling

PubMed Central

O’Kusky, John; Ye, Ping

2012-01-01

Insulin-like growth factor (IGF) signaling greatly impacts the development and growth of the central nervous system (CNS). IGF-I and IGF-II, two ligands of the IGF system, exert a wide variety of actions both during development and in adulthood, promoting the survival and proliferation of neural cells. The IGFs also influence the growth and maturation of neural cells, augmenting dendritic growth and spine formation, axon outgrowth, synaptogenesis, and myelination. Specific IGF actions, however, likely depend on cell type, developmental stage, and local microenvironmental milieu within the brain. Emerging research also indicates that alterations in IGF signaling likely contribute to the pathogenesis of some neurological disorders. This review summarizes experimental studies and shed light on the critical roles of IGF signaling, as well as its mechanisms, during CNS development. PMID:22710100

Lignification of developing maize (Zea mays L.) endosperm transfer cells and starchy endosperm cells

PubMed Central

Rocha, Sara; Monjardino, Paulo; Mendonça, Duarte; da Câmara Machado, Artur; Fernandes, Rui; Sampaio, Paula; Salema, Roberto

2014-01-01

Endosperm transfer cells in maize have extensive cell wall ingrowths that play a key role in kernel development. Although the incorporation of lignin would support this process, its presence in these structures has not been reported in previous studies. We used potassium permanganate staining combined with transmission electron microscopy – energy dispersive X-ray spectrometry as well as acriflavine staining combined with confocal laser scanning microscopy to determine whether the most basal endosperm transfer cells (MBETCs) contain lignified cell walls, using starchy endosperm cells for comparison. We investigated the lignin content of ultrathin sections of MBETCs treated with hydrogen peroxide. The lignin content of transfer and starchy cell walls was also determined by the acetyl bromide method. Finally, the relationship between cell wall lignification and MBETC growth/flange ingrowth orientation was evaluated. MBETC walls and ingrowths contained lignin throughout the period of cell growth we monitored. The same was true of the starchy cells, but those underwent an even more extensive growth period than the transfer cells. Both the reticulate and flange ingrowths were also lignified early in development. The significance of the lignification of maize endosperm cell walls is discussed in terms of its impact on cell growth and flange ingrowth orientation. PMID:24688487

Probing Tumor Microenvironment with In Vivo Phage Display

DTIC Science & Technology

2013-07-01

include immune cells (macrophages polymorphonuclear neutrophils, lymphocytes, dendritic cells ), mesenchymal cells (fibroblasts, mesenchymal stem ... cells , immune cells , mesenchymal cells , and extracellular matrix, which are critical to tumor development and progression. Although various probes...example is the production of various growth factors and cytokines by tumor macrophages, which can promote tumor cell growth and angiogenesis

Thyroid hormone increases fibroblast growth factor receptor expression and disrupts cell mechanics in the developing organ of corti

PubMed Central

2013-01-01

Background Thyroid hormones regulate growth and development. However, the molecular mechanisms by which thyroid hormone regulates cell structural development are not fully understood. The mammalian cochlea is an intriguing system to examine these mechanisms, as cellular structure plays a key role in tissue development, and thyroid hormone is required for the maturation of the cochlea in the first postnatal week. Results In hypothyroid conditions, we found disruptions in sensory outer hair cell morphology and fewer microtubules in non-sensory supporting pillar cells. To test the functional consequences of these cytoskeletal defects on cell mechanics, we combined atomic force microscopy with live cell imaging. Hypothyroidism stiffened outer hair cells and supporting pillar cells, but pillar cells ultimately showed reduced cell stiffness, in part from a lack of microtubules. Analyses of changes in transcription and protein phosphorylation suggest that hypothyroidism prolonged expression of fibroblast growth factor receptors, and decreased phosphorylated Cofilin. Conclusions These findings demonstrate that thyroid hormones may be involved in coordinating the processes that regulate cytoskeletal dynamics and suggest that manipulating thyroid hormone sensitivity might provide insight into the relationship between cytoskeletal formation and developing cell mechanical properties. PMID:23394545

Development of human epithelial cell systems for radiation risk assessment

NASA Astrophysics Data System (ADS)

Yang, C. H.; Craise, L. M.

1994-10-01

The most important health effect of space radiation for astronauts is cancer induction. For radiation risk assessment, an understanding of carcinogenic effect of heavy ions in human cells is most essential. In our laboratory, we have successfully developed a human mammary epithelial cell system for studying the neoplastic transformation in vitro. Growth variants were obtained from heavy ion irradiated immortal mammary cell line. These cloned growth variants can grow in regular tissue culture media and maintain anchorage dependent growth and density inhibition property. Upon further irradiation with high-LET radiation, transformed foci were found. Experimental results from these studies suggest that multiexposure of radiation is required to induce neoplastic transformation of human epithelial cells. This multihits requirement may be due to high genomic stability of human cells. These growth variants can be useful model systems for space flight experiments to determine the carcinogenic effect of space radiation in human epithelial cells.

Development of human epithelial cell systems for radiation risk assessment

NASA Technical Reports Server (NTRS)

Yang, C. H.; Craise, L. M.

1994-01-01

The most important health effect of space radiation for astronauts is cancer induction. For radiation risk assessment, an understanding of carcinogenic effect of heavy ions in human cells is most essential. In our laboratory, we have successfully developed a human mammary epithelial cell system for studying the neoplastic transformation in vitro. Growth variants were obtained from heavy ion irradiated immortal mammary cell line. These cloned growth variants can grow in regular tissue culture media and maintain anchorage dependent growth and density inhibition property. Upon further irradiation with high-Linear Energy Transfer (LET) radiation, transformed foci were found. Experimental results from these studies suggest that multiexposure of radiation is required to induce neoplastic tranformation of human epithelial cells. This multihits requirement may be due to high genomic stability of human cells. These growth variants can be useful model systems for space flight experiments to determine the carcinogenic effect of space radiation in human epithelial cells.

RNAi silenced Dd-grp94 (Dictyostelium discoideum glucose-regulated protein 94 kDa) cell lines in Dictyostelium exhibit marked reduction in growth rate and delay in development.

PubMed

Baviskar, Sandhya N; Shields, Malcolm S

2010-01-01

Glucose-regulated 94 kDa protein (Grp94) is a resident of the endoplasmic reticulum (ER) of multicellular eukaryotes. It is a constitutively expressed protein that is overexpressed in certain abnormal conditions of the cell such as depletion of glucose and calcium, and low oxygen and pH. The protein is also implicated in diseased conditions like cancer and Alzheimer's disease. In this study, the consequences of downregulation of Grp94 were investigated at both unicellular and multicellular stages of Dictyostelium discoideum. Previous studies have shown the expression of Dd-Grp94 (Dictyostelium discoideum glucose-regulated 94 kDa protein) in wild-type cells varies during development, and overexpression of Dd-Grp94 leads to abnormal cell shape and inhibition of development (i.e., formation of fruiting bodies). Grp94 is a known calcium binding protein and an efficient calcium buffer. Therefore, in the present study we hypothesized that downregulation of Dd-Grp94 protein would affect Dictyostelium cell structure, growth, and development. We found that Dd-grp94 RNAi recombinants exhibited reduced growth rate, cell size, and a subtle change in cell motility compared to the parental cells. The recombinants also exhibited a delay in development and small fruiting bodies. These results establish that Dd-grp94 plays a crucial role in determining normal cell structure, growth and differentiation.

A plant cell division algorithm based on cell biomechanics and ellipse-fitting.

PubMed

Abera, Metadel K; Verboven, Pieter; Defraeye, Thijs; Fanta, Solomon Workneh; Hertog, Maarten L A T M; Carmeliet, Jan; Nicolai, Bart M

2014-09-01

The importance of cell division models in cellular pattern studies has been acknowledged since the 19th century. Most of the available models developed to date are limited to symmetric cell division with isotropic growth. Often, the actual growth of the cell wall is either not considered or is updated intermittently on a separate time scale to the mechanics. This study presents a generic algorithm that accounts for both symmetrically and asymmetrically dividing cells with isotropic and anisotropic growth. Actual growth of the cell wall is simulated simultaneously with the mechanics. The cell is considered as a closed, thin-walled structure, maintained in tension by turgor pressure. The cell walls are represented as linear elastic elements that obey Hooke's law. Cell expansion is induced by turgor pressure acting on the yielding cell-wall material. A system of differential equations for the positions and velocities of the cell vertices as well as for the actual growth of the cell wall is established. Readiness to divide is determined based on cell size. An ellipse-fitting algorithm is used to determine the position and orientation of the dividing wall. The cell vertices, walls and cell connectivity are then updated and cell expansion resumes. Comparisons are made with experimental data from the literature. The generic plant cell division algorithm has been implemented successfully. It can handle both symmetrically and asymmetrically dividing cells coupled with isotropic and anisotropic growth modes. Development of the algorithm highlighted the importance of ellipse-fitting to produce randomness (biological variability) even in symmetrically dividing cells. Unlike previous models, a differential equation is formulated for the resting length of the cell wall to simulate actual biological growth and is solved simultaneously with the position and velocity of the vertices. The algorithm presented can produce different tissues varying in topological and geometrical properties. This flexibility to produce different tissue types gives the model great potential for use in investigations of plant cell division and growth in silico.

The development of wing shape in Lepidoptera: mitotic density, not orientation, is the primary determinant of shape.

PubMed

Nijhout, H Frederik; Cinderella, Margaret; Grunert, Laura W

2014-03-01

The wings of butterflies and moths develop from imaginal disks whose structure is always congruent with the final adult wing. It is therefore possible to map every point on the imaginal disk to a location on the adult wing throughout ontogeny. We studied the growth patterns of the wings of two distantly related species with very different adult wing shapes, Junonia coenia and Manduca sexta. The shape of the wing disks change throughout their growth phase in a species-specific pattern. We measured mitotic densities and mitotic orientation in successive stages of wing development approximately one cell division apart. Cell proliferation was spatially patterned, and the density of mitoses was highly correlated with local growth. Unlike other systems in which the direction of mitoses has been viewed as the primary determinant of directional growth, we found that in these two species the direction of growth was only weakly correlated with the orientation of mitoses. Directional growth appears to be imposed by a constantly changing spatial pattern of cell division coupled with a weak bias in the orientation of cell division. Because growth and cell division in imaginal disk require ecdysone and insulin signaling, the changing spatial pattern of cell division may due to a changing pattern of expression of receptors or downstream elements in the signaling pathways for one or both of these hormones. Evolution of wing shape comes about by changes in the progression of spatial patterns of cell division. © 2014 Wiley Periodicals, Inc.

Induction of endothelial cell proliferation by angiogenic factors released by activated monocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pakala, Rajbabu; Watanabe, Takuya; Benedict, Claude R

2002-06-01

Introduction: Cell-cell interaction is an essential component of atherosclerotic plaque development. Activated monocytes appear to play a central role in the development of atherosclerosis, not only through foam cell formation but also via the production of various growth factors that induce proliferation of different cell types that are involved in the plaque development. Using serum free co-culture method, we determined the effect of monocytes on endothelial cell proliferation. Methods: Endothelial cell proliferation is determined by the amount of [{sup 3}H]thymidine incorporated in to the DNA. Basic fibroblast growth factor (b-FGF), vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8) levels inmore » the conditioned medium were determined by ELISA. Results: Conditioned medium from unactivated monocytes partially inhibited endothelial cell proliferation, whereas conditioned medium from activated monocytes promoted endothelial cell proliferation. The mitogenic effect of conditioned medium derived from activated monocytes is due to the presence of b-FGF, VEGF and IL-8. Neutralizing antibodies against b-FGF, VEGF and IL-8 partially reversed the mitogenic effect of conditioned medium derived from activated monocytes. When b-FGF, VEGF and IL-8 were immunoprecipitated from conditioned medium derived from activated monocytes, it is less mitogenic to endothelial cells. Conclusion: Activated monocytes may play an important role in the development of atherosclerotic plaque by producing endothelial cell growth factors.« less

Canine corneal epithelial cells possess a sustained proliferative capacity and generate a spontaneously derived cell line.

PubMed

Morita, Maresuke; Fujita, Naoki; Abe, Momoko; Hayashimoto, Koji; Nakagawa, Takayuki; Nishimura, Ryohei; Tsuzuki, Keiko

2018-06-01

We have previously reported characteristics of canine corneal epithelial cells in vitro and found that canine corneal epithelial cells could maintain their proliferative capacity even after continuous culture without the use of feeder cells and growth promoting additives. The objective of this study was to elucidate proliferative characteristics of canine corneal epithelial cells independent of feeder cells and growth promoting additives, with the aim of developing a spontaneously derived corneal epithelial cell line. Canine and rabbit corneal epithelial cells were harvested from the limbus and cultured with, or without, feeder cells and growth promoting additives, and both were passaged continuously until growth arrest. Canine corneal epithelial cells could proliferate independently, and could be passaged more times than rabbit cells. A canine corneal epithelial cell line, cCEpi, which could be passaged more than 100 times without using feeder cells and growth promoting additives, was established. cCEpi cells maintained a cell morphology close to the primary culture and expressed p63, cytokeratin 15 (K15), and K3. Although changes in colony morphology, shortening of the population doubling time and a heteroploid karyotype were observed, cCEpi was not tumorigenic. Stratified cell sheets cultured from cCEpi were morphologically and immunohistologically similar to sheets cultivated from early passage cells. In conclusion, canine corneal epithelial cells can proliferate independent of feeder cells and growth promoting additives. cCEpi maintains properties similar to normal corneal epithelial cells and could be a useful source for studies in cellular biology and for developing novel therapies. Copyright © 2018 Elsevier Ltd. All rights reserved.

Promotion of human early embryonic development and blastocyst outgrowth in vitro using autocrine/paracrine growth factors.

PubMed

Kawamura, Kazuhiro; Chen, Yuan; Shu, Yimin; Cheng, Yuan; Qiao, Jie; Behr, Barry; Pera, Renee A Reijo; Hsueh, Aaron J W

2012-01-01

Studies using animal models demonstrated the importance of autocrine/paracrine factors secreted by preimplantation embryos and reproductive tracts for embryonic development and implantation. Although in vitro fertilization-embryo transfer (IVF-ET) is an established procedure, there is no evidence that present culture conditions are optimal for human early embryonic development. In this study, key polypeptide ligands known to be important for early embryonic development in animal models were tested for their ability to improve human early embryo development and blastocyst outgrowth in vitro. We confirmed the expression of key ligand/receptor pairs in cleavage embryos derived from discarded human tri-pronuclear zygotes and in human endometrium. Combined treatment with key embryonic growth factors (brain-derived neurotrophic factor, colony-stimulating factor, epidermal growth factor, granulocyte macrophage colony-stimulating factor, insulin-like growth factor-1, glial cell-line derived neurotrophic factor, and artemin) in serum-free media promoted >2.5-fold the development of tri-pronuclear zygotes to blastocysts. For normally fertilized embryos, day 3 surplus embryos cultured individually with the key growth factors showed >3-fold increases in the development of 6-8 cell stage embryos to blastocysts and >7-fold increase in the proportion of high quality blastocysts based on Gardner's criteria. Growth factor treatment also led to a 2-fold promotion of blastocyst outgrowth in vitro when day 7 surplus hatching blastocysts were used. When failed-to-be-fertilized oocytes were used to perform somatic cell nuclear transfer (SCNT) using fibroblasts as donor karyoplasts, inclusion of growth factors increased the progression of reconstructed SCNT embryos to >4-cell stage embryos. Growth factor supplementation of serum-free cultures could promote optimal early embryonic development and implantation in IVF-ET and SCNT procedures. This approach is valuable for infertility treatment and future derivation of patient-specific embryonic stem cells.

Absence of the Polar Organizing Protein PopZ Results in Reduced and Asymmetric Cell Division in Agrobacterium tumefaciens

PubMed Central

Howell, Matthew; Aliashkevich, Alena; Salisbury, Anne K.; Cava, Felipe; Bowman, Grant R.

2017-01-01

ABSTRACT Agrobacterium tumefaciens is a rod-shaped bacterium that grows by polar insertion of new peptidoglycan during cell elongation. As the cell cycle progresses, peptidoglycan synthesis at the pole ceases prior to insertion of new peptidoglycan at midcell to enable cell division. The A. tumefaciens homolog of the Caulobacter crescentus polar organelle development protein PopZ has been identified as a growth pole marker and a candidate polar growth-promoting factor. Here, we characterize the function of PopZ in cell growth and division of A. tumefaciens. Consistent with previous observations, we observe that PopZ localizes specifically to the growth pole in wild-type cells. Despite the striking localization pattern of PopZ, we find the absence of the protein does not impair polar elongation or cause major changes in the peptidoglycan composition. Instead, we observe an atypical cell length distribution, including minicells, elongated cells, and cells with ectopic poles. Most minicells lack DNA, suggesting a defect in chromosome segregation. Furthermore, the canonical cell division proteins FtsZ and FtsA are misplaced, leading to asymmetric sites of cell constriction. Together, these data suggest that PopZ plays an important role in the regulation of chromosome segregation and cell division. IMPORTANCE A. tumefaciens is a bacterial plant pathogen and a natural genetic engineer. However, very little is known about the spatial and temporal regulation of cell wall biogenesis that leads to polar growth in this bacterium. Understanding the molecular basis of A. tumefaciens growth may allow for the development of innovations to prevent disease or to promote growth during biotechnology applications. Finally, since many closely related plant and animal pathogens exhibit polar growth, discoveries in A. tumefaciens may be broadly applicable for devising antimicrobial strategies. PMID:28630123

CLIC4 Moves Into Nucleus to Stabilize Anti-Growth Signal | Center for Cancer Research

Cancer.gov

In cancer, the delicate balance of signaling pathways that control cell growth and function is disrupted. One signaling pathway commonly altered in cancer is the TGF-beta pathway. TGF-beta significantly inhibits growth of normal cells, particularly epithelial cells. Many cancer cells have developed ways to bypass one or more steps of this pathway in order to achieve

Wingless promotes proliferative growth in a gradient-independent manner.

PubMed

Baena-Lopez, Luis Alberto; Franch-Marro, Xavier; Vincent, Jean-Paul

2009-10-06

Morphogens form concentration gradients that organize patterns of cells and control growth. It has been suggested that, rather than the intensity of morphogen signaling, it is its gradation that is the relevant modulator of cell proliferation. According to this view, the ability of morphogens to regulate growth during development depends on their graded distributions. Here, we describe an experimental test of this model for Wingless, one of the key organizers of wing development in Drosophila. Maximal Wingless signaling suppresses cellular proliferation. In contrast, we found that moderate and uniform amounts of exogenous Wingless, even in the absence of endogenous Wingless, stimulated proliferative growth. Beyond a few cell diameters from the source, Wingless was relatively constant in abundance and thus provided a homogeneous growth-promoting signal. Although morphogen signaling may act in combination with as yet uncharacterized graded growth-promoting pathways, we suggest that the graded nature of morphogen signaling is not required for proliferation, at least in the developing Drosophila wing, during the main period of growth.

Bestatin Inhibits Cell Growth, Cell Division, and Spore Cell Differentiation in Dictyostelium discoideum

PubMed Central

Poloz, Yekaterina; Catalano, Andrew

2012-01-01

Bestatin methyl ester (BME) is an inhibitor of Zn2+-binding aminopeptidases that inhibits cell proliferation and induces apoptosis in normal and cancer cells. We have used Dictyostelium as a model organism to study the effects of BME. Only two Zn2+-binding aminopeptidases have been identified in Dictyostelium to date, puromycin-sensitive aminopeptidase A and B (PsaA and PsaB). PSA from other organisms is known to regulate cell division and differentiation. Here we show that PsaA is differentially expressed throughout growth and development of Dictyostelium, and its expression is regulated by developmental morphogens. We present evidence that BME specifically interacts with PsaA and inhibits its aminopeptidase activity. Treatment of cells with BME inhibited the rate of cell growth and the frequency of cell division in growing cells and inhibited spore cell differentiation during late development. Overexpression of PsaA-GFP (where GFP is green fluorescent protein) also inhibited spore cell differentiation but did not affect growth. Using chimeras, we have identified that nuclear versus cytoplasmic localization of PsaA affects the choice between stalk or spore cell differentiation pathway. Cells that overexpressed PsaA-GFP (primarily nuclear) differentiated into stalk cells, while cells that overexpressed PsaAΔNLS2-GFP (cytoplasmic) differentiated into spores. In conclusion, we have identified that BME inhibits cell growth, division, and differentiation in Dictyostelium likely through inhibition of PsaA. PMID:22345351

Bovine ovarian follicular growth and development correlate with lysophosphatidic acid expression.

PubMed

Sinderewicz, Emilia; Grycmacher, Katarzyna; Boruszewska, Dorota; Kowalczyk-Zięba, Ilona; Staszkiewicz, Joanna; Ślężak, Tomasz; Woclawek-Potocka, Izabela

2018-01-15

The basis of successful reproduction is proper ovarian follicular growth and development. In addition to prostaglandins and vascular endothelial growth factor, a number of novel factors are suggested as important regulators of follicular growth and development: PGES, TFG, CD36, RABGAP1, DBI and BTC. This study focuses on examining the expression of these factors in granulosa and thecal cells that originate from different ovarian follicle types and their link with the expression of lysophosphatidic acid (LPA), known local regulator of reproductive functions in the cow. Ovarian follicles were divided into healthy, transitional, and atretic categories. The mRNA expression levels for PGES, TFG, CD36, RABGAP1, DBI and BTC in granulosa and thecal cells in different follicle types were measured by real-time PCR. The correlations among expression of enzymes synthesizing LPA (autotaxin, phospholipase A2), receptors for LPA and examined factors were measured. Immunolocalization of PGES, TFG, CD36, RABGAP1, DBI and BTC was examined by immunohistochemistry. We investigated follicle-type dependent mRNA expression of factors potentially involved in ovarian follicular growth and development, both in granulosa and thecal cells of bovine ovarian follicles. Strong correlations among receptors for LPA, enzymes synthesizing LPA, and the examined factors in healthy and transitional follicles were observed, with its strongest interconnection with TFG, DBI and RABGAP1 in granulosa cells, and TFG in thecal cells; whereas no correlations in atretic follicles were detected. A greater number of correlations were found in thecal cells than in granulosa cells as well as in healthy follicles than in transitional follicles. These data indicate the role of LPA in the growth, development and physiology of the bovine ovarian follicle. Copyright © 2017 Elsevier Inc. All rights reserved.

The development and geometry of shape change in Arabidopsis thaliana cotyledon pavement cells

PubMed Central

2011-01-01

Background The leaf epidermis is an important architectural control element that influences the growth properties of underlying tissues and the overall form of the organ. In dicots, interdigitated pavement cells are the building blocks of the tissue, and their morphogenesis includes the assembly of specialized cell walls that surround the apical, basal, and lateral (anticlinal) cell surfaces. The microtubule and actin cytoskeletons are highly polarized along the cortex of the anticlinal wall; however, the relationships between these arrays and cell morphogenesis are unclear. Results We developed new quantitative tools to compare population-level growth statistics with time-lapse imaging of cotyledon pavement cells in an intact tissue. The analysis revealed alternating waves of lobe initiation and a phase of lateral isotropic expansion that persisted for days. During lateral isotropic diffuse growth, microtubule organization varied greatly between cell surfaces. Parallel microtubule bundles were distributed unevenly along the anticlinal surface, with subsets marking stable cortical domains at cell indentations and others clearly populating the cortex within convex cell protrusions. Conclusions Pavement cell morphogenesis is discontinuous, and includes punctuated phases of lobe initiation and lateral isotropic expansion. In the epidermis, lateral isotropic growth is independent of pavement cell size and shape. Cortical microtubules along the upper cell surface and stable cortical patches of anticlinal microtubules may coordinate the growth behaviors of orthogonal cell walls. This work illustrates the importance of directly linking protein localization data to the growth behavior of leaf epidermal cells. PMID:21284861

The development and geometry of shape change in Arabidopsis thaliana cotyledon pavement cells.

PubMed

Zhang, Chunhua; Halsey, Leah E; Szymanski, Daniel B

2011-02-01

The leaf epidermis is an important architectural control element that influences the growth properties of underlying tissues and the overall form of the organ. In dicots, interdigitated pavement cells are the building blocks of the tissue, and their morphogenesis includes the assembly of specialized cell walls that surround the apical, basal, and lateral (anticlinal) cell surfaces. The microtubule and actin cytoskeletons are highly polarized along the cortex of the anticlinal wall; however, the relationships between these arrays and cell morphogenesis are unclear. We developed new quantitative tools to compare population-level growth statistics with time-lapse imaging of cotyledon pavement cells in an intact tissue. The analysis revealed alternating waves of lobe initiation and a phase of lateral isotropic expansion that persisted for days. During lateral isotropic diffuse growth, microtubule organization varied greatly between cell surfaces. Parallel microtubule bundles were distributed unevenly along the anticlinal surface, with subsets marking stable cortical domains at cell indentations and others clearly populating the cortex within convex cell protrusions. Pavement cell morphogenesis is discontinuous, and includes punctuated phases of lobe initiation and lateral isotropic expansion. In the epidermis, lateral isotropic growth is independent of pavement cell size and shape. Cortical microtubules along the upper cell surface and stable cortical patches of anticlinal microtubules may coordinate the growth behaviors of orthogonal cell walls. This work illustrates the importance of directly linking protein localization data to the growth behavior of leaf epidermal cells.

Expression of insulin-like growth factor-1 and proliferating cell nuclear antigen in human pulp cells of teeth with complete and incomplete root development.

PubMed

Caviedes-Bucheli, J; Canales-Sánchez, P; Castrillón-Sarria, N; Jovel-Garcia, J; Alvarez-Vásquez, J; Rivero, C; Azuero-Holguín, M M; Diaz, E; Munoz, H R

2009-08-01

To quantify the expression of insulin-like growth factor-1 (IGF-1) and proliferating cell nuclear antigen (PCNA) in human pulp cells of teeth with complete or incomplete root development, to support the specific role of IGF-1 in cell proliferation during tooth development and pulp reparative processes. Twenty six pulp samples were obtained from freshly extracted human third molars, equally divided in two groups according to root development stage (complete or incomplete root development). All samples were processed and immunostained to determine the expression of IGF-1 and PCNA in pulp cells. Sections were observed with a light microscope at 80x and morphometric analyses were performed to calculate the area of PCNA and IGF-1 immunostaining using digital image software. Mann-Whitney's test was used to determine statistically significant differences between groups (P < 0.05) for each peptide and the co-expression of both. Expression of IGF-1 and PCNA was observed in all human pulp samples with a statistically significant higher expression in cells of pulps having complete root development (P = 0.0009). Insulin-like growth factor-1 and PCNA are expressed in human pulp cells, with a significant greater expression in pulp cells of teeth having complete root development.

The impact of IUGR on pancreatic islet development and β-cell function.

PubMed

Boehmer, Brit H; Limesand, Sean W; Rozance, Paul J

2017-11-01

Placental insufficiency is a primary cause of intrauterine growth restriction (IUGR). IUGR increases the risk of developing type 2 diabetes mellitus (T2DM) throughout life, which indicates that insults from placental insufficiency impair β-cell development during the perinatal period because β-cells have a central role in the regulation of glucose tolerance. The severely IUGR fetal pancreas is characterized by smaller islets, less β-cells, and lower insulin secretion. Because of the important associations among impaired islet growth, β-cell dysfunction, impaired fetal growth, and the propensity for T2DM, significant progress has been made in understanding the pathophysiology of IUGR and programing events in the fetal endocrine pancreas. Animal models of IUGR replicate many of the observations in severe cases of human IUGR and allow us to refine our understanding of the pathophysiology of developmental and functional defects in islet from IUGR fetuses. Almost all models demonstrate a phenotype of progressive loss of β-cell mass and impaired β-cell function. This review will first provide evidence of impaired human islet development and β-cell function associated with IUGR and the impact on glucose homeostasis including the development of glucose intolerance and diabetes in adulthood. We then discuss evidence for the mechanisms regulating β-cell mass and insulin secretion in the IUGR fetus, including the role of hypoxia, catecholamines, nutrients, growth factors, and pancreatic vascularity. We focus on recent evidence from experimental interventions in established models of IUGR to understand better the pathophysiological mechanisms linking placental insufficiency with impaired islet development and β-cell function. © 2017 Society for Endocrinology.

Regulation of cellular growth by the Drosophila target of rapamycin dTOR

PubMed Central

Zhang, Hongbing; Stallock, James P.; Ng, Joyce C.; Reinhard, Christoph; Neufeld, Thomas P.

2000-01-01

The TOR protein kinases (TOR1 and TOR2 in yeast; mTOR/FRAP/RAFT1 in mammals) promote cellular proliferation in response to nutrients and growth factors, but their role in development is poorly understood. Here, we show that the Drosophila TOR homolog dTOR is required cell autonomously for normal growth and proliferation during larval development, and for increases in cellular growth caused by activation of the phosphoinositide 3-kinase (PI3K) signaling pathway. As in mammalian cells, the kinase activity of dTOR is required for growth factor-dependent phosphorylation of p70 S6 kinase (p70S6K) in vitro, and we demonstrate that overexpression of p70S6K in vivo can rescue dTOR mutant animals to viability. Loss of dTOR also results in cellular phenotypes characteristic of amino acid deprivation, including reduced nucleolar size, lipid vesicle aggregation in the larval fat body, and a cell type-specific pattern of cell cycle arrest that can be bypassed by overexpression of the S-phase regulator cyclin E. Our results suggest that dTOR regulates growth during animal development by coupling growth factor signaling to nutrient availability. PMID:11069888

Shifting foundations: the mechanical cell wall and development.

PubMed

Braybrook, Siobhan A; Jönsson, Henrik

2016-02-01

The cell wall has long been acknowledged as an important physical mediator of growth in plants. Recent experimental and modelling work has brought the importance of cell wall mechanics into the forefront again. These data have challenged existing dogmas that relate cell wall structure to cell/organ growth, that uncouple elasticity from extensibility, and those which treat the cell wall as a passive and non-stressed material. Within this review we describe experiments and models which have changed the ways in which we view the mechanical cell wall, leading to new hypotheses and research avenues. It has become increasingly apparent that while we often wish to simplify our systems, we now require more complex multi-scale experiments and models in order to gain further insight into growth mechanics. We are currently experiencing an exciting and challenging shift in the foundations of our understanding of cell wall mechanics in growth and development. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Pectin methyl esterase inhibits intrusive and symplastic cell growth in developing wood cells of Populus.

PubMed

Siedlecka, Anna; Wiklund, Susanne; Péronne, Marie-Amélie; Micheli, Fabienne; Lesniewska, Joanna; Sethson, Ingmar; Edlund, Ulf; Richard, Luc; Sundberg, Björn; Mellerowicz, Ewa J

2008-02-01

Wood cells, unlike most other cells in plants, grow by a unique combination of intrusive and symplastic growth. Fibers grow in diameter by diffuse symplastic growth, but they elongate solely by intrusive apical growth penetrating the pectin-rich middle lamella that cements neighboring cells together. In contrast, vessel elements grow in diameter by a combination of intrusive and symplastic growth. We demonstrate that an abundant pectin methyl esterase (PME; EC 3.1.1.11) from wood-forming tissues of hybrid aspen (Populus tremula x tremuloides) acts as a negative regulator of both symplastic and intrusive growth of developing wood cells. When PttPME1 expression was up- and down-regulated in transgenic aspen trees, the PME activity in wood-forming tissues was correspondingly altered. PME removes methyl ester groups from homogalacturonan (HG) and transgenic trees had modified HG methylesterification patterns, as demonstrated by two-dimensional nuclear magnetic resonance and immunostaining using PAM1 and LM7 antibodies. In situ distributions of PAM1 and LM7 epitopes revealed changes in pectin methylesterification in transgenic trees that were specifically localized in expanding wood cells. The results show that en block deesterification of HG by PttPME1 inhibits both symplastic growth and intrusive growth. PttPME1 is therefore involved in mechanisms determining fiber width and length in the wood of aspen trees.

Physiological studies of chloramine resistance developed by Klebsiella pneumoniae under low-nutrient growth conditions.

PubMed Central

Stewart, M H; Olson, B H

1992-01-01

This study investigated the physiological mechanisms of resistance to chloramines developed by Klebsiella pneumoniae grown in a nutrient-limited environment. Growth under these conditions resulted in cells that were smaller than cells grown under high-nutrient conditions and extensively aggregated. Cellular aggregates ranged from 10 to more than 10,000 cells per aggregate, with a mean population aggregate size of 90 cells. This aggregation may have been facilitated by the presence of extracellular polymer material. By using glucose as a reference of capsule content, it was determined that growth under low-nutrient conditions produced cells with 8 x 10(-14) to 41 x 10(-14) g of carbohydrate per cell, with a mean +/- standard deviation of 27 x 10(-14) +/- 16 x 10(-14) g of carbohydrate per cell. In comparison, growth under high-nutrient conditions resulted in 2.7 x 10(-14) to 5.9 x 10(-14) g of carbohydrate per cell, with a mean and standard deviation of 4.3 x 10(-14) +/- 1.2 x 10(-14) g of carbohydrate per cell. Cell wall and cell membrane lipids also varied with growth conditions. The ratio of saturated to unsaturated fatty acids in cells grown under low-nutrient conditions was approximately five times greater than that in cells grown under high-nutrient conditions, suggesting possible differences in membrane permeability. An analysis of sulfhydryl (-SH) groups revealed no quantitative difference with respect to growth conditions. However, upon exposure to chloramines, only 33% of the -SH groups of cells grown under low-nutrient conditions were oxidized, compared with 80% oxidization of -SH groups in cells grown under high-nutrient conditions. The reduced effectiveness of chloramine oxidization of -SH groups in cells grown under low-nutrient conditions may be due to restricted penetration of chloramines into the cells, conformational changes of enzymes, or a combination of both factors. The results of this study suggest that chloramine resistance developed under low-nutrient growth conditions may be a function of multiple physiological factors, including cellular aggregation and protection of sulfhydryl groups within the cell. PMID:1444406

Promotion of SH-SY5Y Cell Growth by Gold Nanoparticles Modified with 6-Mercaptopurine and a Neuron-Penetrating Peptide

NASA Astrophysics Data System (ADS)

Xiao, Yaruo; Zhang, Enqi; Fu, Ailing

2017-12-01

Much effort has been devoted to the discovery of effective biomaterials for nerve regeneration. Here, we reported a novel application of gold nanoparticles (AuNPs) modified with 6-mercaptopurine (6MP) and a neuron-penetrating peptide (RDP) as a neurophic agent to promote proliferation and neurite growth of human neuroblastoma (SH-SY5Y) cells. When the cells were treated with 6MP-AuNPs-RDP conjugates, they showed higher metabolic activity than the control. Moreover, SH-SY5Y cells were transplanted onto the surface coated with 6MP-AuNPs-RDP to examine the effect of neurite development. It can be concluded that 6MP-AuNPs-RDP attached to the cell surface and then internalized into cells, leading to a significant increase of neurite growth. Even though 6MP-AuNPs-RDP-treated cells were recovered from frozen storage, the cells still maintained constant growth, indicating that the cells have excellent tolerance to 6MP-AuNPs-RDP. The results suggested that the 6MP-AuNPs-RDP had promising potential to be developed as a neurophic nanomaterial for neuronal growth.

Polyploidization of glia in neural development links tissue growth to blood-brain barrier integrity.

PubMed

Unhavaithaya, Yingdee; Orr-Weaver, Terry L

2012-01-01

Proper development requires coordination in growth of the cell types composing an organ. Many plant and animal cells are polyploid, but how these polyploid tissues contribute to organ growth is not well understood. We found the Drosophila melanogaster subperineurial glia (SPG) to be polyploid, and ploidy is coordinated with brain mass. Inhibition of SPG polyploidy caused rupture of the septate junctions necessary for the blood-brain barrier. Thus, the increased SPG cell size resulting from polyploidization is required to maintain the SPG envelope surrounding the growing brain. Polyploidization likely is a conserved strategy to coordinate tissue growth during organogenesis, with potential vertebrate examples.

Development of experimental tumors formed by mouse and human embryonic stem and teratocarcinoma cells after subcutaneous and intraperitoneal transplantations into immunodeficient and immunocompetent mice.

PubMed

Gordeeva, O F; Nikonova, T M

2013-01-01

Pluripotent stem cells represent an attractive cell source for regenerative medicine. However, the risk of teratoma formation after transplantation restricts their clinical application. Therefore, to adequately evaluate the potential risk of tumorigenicity after cell transplantation into human tissues, effective animal transplantation assays need to be developed. We performed a multiparameter (cell number, transplantation site, cell type, host) comparative analysis of the efficiency of tumor development after transplantation of mouse and human embryonic stem (ES) cells and their malignant counterparts, teratocarcinoma (EC) cells, into animal recipients and revealed several key correlations. We found that the efficiency of tumor growth was higher after intraperitoneal than after subcutaneous transplantations of all cell lines studied. The minimal cell numbers sufficient for tumor growth in immunodeficient nude mice were 100-fold lower for intraperitoneal than for subcutaneous transplantations of mouse and human ES cells (10(3) vs. 10(5) and 10(4) vs. 10(6), respectively). Moreover, mouse ES and EC cells formed tumors in immunodeficient and immunocompetent mice more effectively than human ES and EC cells. After intraperitoneal transplantation of 10(3), 10(4), and 10(5) mouse ES cells, teratomas developed in 83%, 100%, and 100% of nude mice, whereas after human ES cell transplantation, teratomas developed in 0%, 17%, and 60%, respectively. In addition, malignant mouse and human EC cells initiated tumor growth after intraperitoneal transplantation significantly faster and more effectively than ES cells. Mouse and human ES cells formed different types of teratomas containing derivatives of three germ layers but different numbers of undifferentiated cells. ES cell-like sublines with differentiation potential similar to the parental cell line were recloned only from mouse, but not from human, ES cell teratomas. These findings provide new information about the possibility and efficiency of tumor growth after transplantation of pluripotent stem cells. This information allows one to predict and possibly prevent the possible risks of tumorigenicity that could arise from stem cell therapeutics.

The Role of Tumor Associated Macrophage in Recurrent Growth of Tumor Stem Cell

DTIC Science & Technology

2012-09-01

According to the recent cancer stem cell (CSC) theory, recurrent tumor must arise from a dormant tumor stem cell whose re- growth is triggered by...shifting of microenvironment. This project aims at clarifying the roles of TAM in recurrent growth of dormant stem cell in breast cancer. We hypothesize...the stem cell . We have established necessary mouse colonies and also developed the method to generate TAM. We have also shown that TAM indeed

TGFbeta type II receptor signaling controls Schwann cell death and proliferation in developing nerves.

PubMed

D'Antonio, Maurizio; Droggiti, Anna; Feltri, M Laura; Roes, Jürgen; Wrabetz, Lawrence; Mirsky, Rhona; Jessen, Kristján R

2006-08-16

During development, Schwann cell numbers are precisely adjusted to match the number of axons. It is essentially unknown which growth factors or receptors carry out this important control in vivo. Here, we tested whether the type II transforming growth factor (TGF) beta receptor has a role in this process. We generated a conditional knock-out mouse in which the type II TGFbeta receptor is specifically ablated only in Schwann cells. Inactivation of the receptor, evident at least from embryonic day 18, resulted in suppressed Schwann cell death in normally developing and injured nerves. Notably, the mutants also showed a strong reduction in Schwann cell proliferation. Consequently, Schwann cell numbers in wild-type and mutant nerves remained similar. Lack of TGFbeta signaling did not appear to affect other processes in which TGFbeta had been implicated previously, including myelination and response of adult nerves to injury. This is the first in vivo evidence for a growth factor receptor involved in promoting Schwann cell division during development and the first genetic evidence for a receptor that controls normal developmental Schwann cell death.

Transforming growth factor (TGF)beta, fibroblast growth factor (FGF) and retinoid signalling pathways promote pancreatic exocrine gene expression in mouse embryonic stem cells.

PubMed Central

Skoudy, Anouchka; Rovira, Meritxell; Savatier, Pierre; Martin, Franz; León-Quinto, Trinidad; Soria, Bernat; Real, Francisco X

2004-01-01

Extracellular signalling cues play a major role in the activation of differentiation programmes. Mouse embryonic stem (ES) cells are pluripotent and can differentiate into a wide variety of specialized cells. Recently, protocols designed to induce endocrine pancreatic differentiation in vitro have been designed but little information is currently available concerning the potential of ES cells to differentiate into acinar pancreatic cells. By using conditioned media of cultured foetal pancreatic rudiments, we demonstrate that ES cells can respond in vitro to signalling pathways involved in exocrine development and differentiation. In particular, modulation of the hedgehog, transforming growth factor beta, retinoid, and fibroblast growth factor pathways in ES cell-derived embryoid bodies (EB) resulted in increased levels of transcripts encoding pancreatic transcription factors and cytodifferentiation markers, as demonstrated by RT-PCR. In EB undergoing spontaneous differentiation, expression of the majority of the acinar genes (i.e. amylase, carboxypeptidase A and elastase) was induced after the expression of endocrine genes, as occurs in vivo during development. These data indicate that ES cells can undergo exocrine pancreatic differentiation with a kinetic pattern of expression reminiscent of pancreas development in vivo and that ES cells can be coaxed to express an acinar phenotype by activation of signalling pathways known to play a role in pancreatic development and differentiation. PMID:14733613

Live-cell mass profiling: an emerging approach in quantitative biophysics.

PubMed

Zangle, Thomas A; Teitell, Michael A

2014-12-01

Cell mass, volume and growth rate are tightly controlled biophysical parameters in cellular development and homeostasis, and pathological cell growth defines cancer in metazoans. The first measurements of cell mass were made in the 1950s, but only recently have advances in computer science and microfabrication spurred the rapid development of precision mass-quantifying approaches. Here we discuss available techniques for quantifying the mass of single live cells with an emphasis on relative features, capabilities and drawbacks for different applications.

The Dual Role of TGFβ in Human Cancer: From Tumor Suppression to Cancer Metastasis

PubMed Central

Lebrun, Jean-Jacques

2012-01-01

The transforming growth factor-beta (TGFβ) superfamily encompasses widespread and evolutionarily conserved polypeptide growth factors that regulate and orchestrate growth and differentiation in all cell types and tissues. While they regulate asymmetric cell division and cell fate determination during early development and embryogenesis, TGFβ family members play a major regulatory role in hormonal and immune responses, cell growth, cell death and cell immortalization, bone formation, tissue remodeling and repair, and erythropoiesis throughout adult life. The biological and physiological functions of TGFβ, the founding member of this family, and its receptors are of central importance to human diseases, particularly cancer. By regulating cell growth, death, and immortalization, TGFβ signaling pathways exert tumor suppressor effects in normal cells and early carcinomas. Thus, it is not surprising that a high number of human tumors arise due to mutations or deletions in the genes coding for the various TGFβ signaling components. As tumors develop and progress, these protective and cytostatic effects of TGFβ are often lost. TGFβ signaling then switches to promote cancer progression, invasion, and tumor metastasis. The molecular mechanisms underlying this dual role of TGFβ in human cancer will be discussed in depth in this paper, and it will highlight the challenge and importance of developing novel therapeutic strategies specifically aimed at blocking the prometastatic arm of the TGFβ signaling pathway without affecting its tumor suppressive effects. PMID:27340590

Growth and cell wall changes in stem organs under microgravity and hypergravity conditions

NASA Astrophysics Data System (ADS)

Hoson, Takayuki; Soga, Kouichi; Wakabayashi, Kazuyuki; Kamisaka, Seiichiro

Gravity strongly influences plant growth and development, which is fundamentally brought about by modifications to the properties of the cell wall. We have examined the changes in growth and cell wall properties in seedling organs under hypergravity conditions produced by centrifugation and under microgravity conditions in space. Hypergravity stimuli have been shown to decrease the growth rate of various seedling organs. When hypergravity suppressed elongation growth, a decrease in cell wall extensibility (an increase in cell wall rigidity) was induced. Hypergravity has also been shown to increase cell wall thickness in various mate-rials. In addition, a polymerization of certain matrix polysaccharides was brought about by hypergravity: in dicotyledons hypergravity increased the molecular size of xyloglucans, whereas hypergravity increased that of 1,3,1,4-β-glucans in monocotyledonous Gramineae. These mod-ifications to cell wall metabolism may be responsible for a decrease in cell wall extensibility, leading to growth suppression under hypergravity conditions. How then does microgravity in-fluence growth and cell wall properties? Here, there was a possibility that microgravity might induce changes similar to those by hypergravity, because plants have evolved and adapted to 1 g condition for more than 400 million years. However, the changes observed under microgravity conditions in space were just opposite to those induced by hypergravity: stimulation of elonga-tion growth, an increase in cell wall extensibility, and a decrease in cell wall thickness as well as depolymerization of cell wall polysaccharides were brought about in space. Furthermore, growth and cell wall properties varied in proportion to the logarithm of the magnitude of grav-ity in the range from microgravity to hypergravity, as shown in the dose-response relation in light and hormonal responses. Thus, microgravity may be a `stress-less' environment for plant seedlings to grow and develop. Preliminary results obtained by recent Space Seed experiment in the Kibo Module on the International Space Station (PI: S. Kamisaka) suggest that this hypothesis is also applicable to mature Arabidopsis plants.

Fetal programming in meat production.

PubMed

Du, Min; Wang, Bo; Fu, Xing; Yang, Qiyuan; Zhu, Mei-Jun

2015-11-01

Nutrient fluctuations during the fetal stage affects fetal development, which has long-term impacts on the production efficiency and quality of meat. During the early development, a pool of mesenchymal progenitor cells proliferate and then diverge into either myogenic or adipogenic/fibrogenic lineages. Myogenic progenitor cells further develop into muscle fibers and satellite cells, while adipogenic/fibrogenic lineage cells develop into adipocytes, fibroblasts and resident fibro-adipogenic progenitor cells. Enhancing the proliferation and myogenic commitment of progenitor cells during fetal development enhances muscle growth and lean production in offspring. On the other hand, promoting the adipogenic differentiation of adipogenic/fibrogenic progenitor cells inside the muscle increases intramuscular adipocytes and reduces connective tissue, which improves meat marbling and tenderness. Available studies in mammalian livestock, including cattle, sheep and pigs, clearly show the link between maternal nutrition and the quantity and quality of meat production. Similarly, chicken muscle fibers develop before hatching and, thus, egg and yolk sizes and hatching temperature affect long-term growth performance and meat production of chicken. On the contrary, because fishes are able to generate new muscle fibers lifelong, the impact of early nutrition on fish growth performance is expected to be minor, which requires further studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Growth and development of cultured carrot cells and embryos under spaceflight conditions

NASA Technical Reports Server (NTRS)

Krikorian, A. D.; Dutcher, F. R.; Quinn, C. E.; Steward, F. C.

1981-01-01

Morphogenetically competent proembryonic cells and well-developed somatic embryos of carrot at two levels of organization were exposed for 18.5 days to a hypogravity environment aboard the Soviet Biosatellite Cosmos 1129. It was confirmed that cultured totipotent cells of carrot can give rise to embryos with well-developed roots and minimally developed shoots. It was also shown that the space hypogravity environment could support the further growth of already-organized, later somatic embryonic stages and give rise to fully developed embryo-plantlets with roots and shoots.

Enhanced gastric cancer growth potential of mesenchymal stem cells derived from gastric cancer tissues educated by CD4+ T cells.

PubMed

Xu, Rongman; Zhao, Xiangdong; Zhao, Yuanyuan; Chen, Bin; Sun, Li; Xu, Changgen; Shen, Bo; Wang, Mei; Xu, Wenrong; Zhu, Wei

2018-04-01

Gastric cancer mesenchymal stem cells (GC-MSCs) can promote the development of tumour growth. The tumour-promoting role of tumour-associated MSCs and T cells has been demonstrated. T cells as the major immune cells may influence and induce a pro-tumour phenotype in MSCs. This study focused on whether CD4 + T cells can affect GC-MSCs to promote gastric cancer growth. CD4 + T cells upregulation of programmed death ligand 1 (PD-L1) expression in GC-MSCs through the phosphorylated signal transducer and activator of transcription (p-STAT3) signalling pathway was confirmed by immunofluorescence, western blotting and RT-PCR. Migration of GC cells was detected by Transwell migration assay, and apoptosis of GC cells was measured by flow cytometry using annexin V/propidium iodide double staining. CD4 + T cell-primed GC-MSCs promoted GC growth in a subcutaneously transplanted tumour model in BALB/c nu/nu mice. Gastric cancer mesenchymal stem cells stimulated by activated CD4 + T cells promoted migration of GC cells and enhanced GC growth potential in BALB/c nu/nu xenografts. PD-L1 upregulation of GC-MSCs stimulated by CD4 + T cells was mediated through the p-STAT3 signalling pathway. CD4 + T cells-primed GC-MSCs have greater GC volume and growth rate-promoting role than GC-MSCs, with cancer cell-intrinsic PD-1/mammalian target of rapamycin (mTOR) signalling activation. This study showed that GC-MSCs are plastic. The immunophenotype of GC-MSCs stimulated by CD4 + T cells has major changes that may influence tumour cell growth. This research was based on the interaction between tumour cells, MSCs and immune cells, providing a new understanding of the development and immunotherapy of GC. © 2017 John Wiley & Sons Ltd.

Potential use of the bioreactor to determine effects of microgravity and other environmental parameters on growth of hybridoma cells

NASA Technical Reports Server (NTRS)

Ley, Kenneth D.

1987-01-01

It is argued that the bioreactor being developed at NASA will allow researchers to determine the optimal conditions (e.g., pH, O sub 2, CO sub 2, nutrients) for growth of hybridoma cells, and to determine whether cell growth and antibody production are enhanced in the microgravity of space.

Modular control of endothelial sheet migration

PubMed Central

Vitorino, Philip; Meyer, Tobias

2008-01-01

Growth factor-induced migration of endothelial cell monolayers enables embryonic development, wound healing, and angiogenesis. Although collective migration is widespread and therapeutically relevant, the underlying mechanism by which cell monolayers respond to growth factor, sense directional signals, induce motility, and coordinate individual cell movements is only partially understood. Here we used RNAi to identify 100 regulatory proteins that enhance or suppress endothelial sheet migration into cell-free space. We measured multiple live-cell migration parameters for all siRNA perturbations and found that each targeted protein primarily regulates one of four functional outputs: cell motility, directed migration, cell–cell coordination, or cell density. We demonstrate that cell motility regulators drive random, growth factor-independent motility in the presence or absence of open space. In contrast, directed migration regulators selectively transduce growth factor signals to direct cells along the monolayer boundary toward open space. Lastly, we found that regulators of cell–cell coordination are growth factor-independent and reorient randomly migrating cells inside the sheet when boundary cells begin to migrate. Thus, cells transition from random to collective migration through a modular control system, whereby growth factor signals convert boundary cells into pioneers, while cells inside the monolayer reorient and follow pioneers through growth factor-independent migration and cell–cell coordination. PMID:19056882

A plant cell division algorithm based on cell biomechanics and ellipse-fitting

PubMed Central

Abera, Metadel K.; Verboven, Pieter; Defraeye, Thijs; Fanta, Solomon Workneh; Hertog, Maarten L. A. T. M.; Carmeliet, Jan; Nicolai, Bart M.

2014-01-01

Background and Aims The importance of cell division models in cellular pattern studies has been acknowledged since the 19th century. Most of the available models developed to date are limited to symmetric cell division with isotropic growth. Often, the actual growth of the cell wall is either not considered or is updated intermittently on a separate time scale to the mechanics. This study presents a generic algorithm that accounts for both symmetrically and asymmetrically dividing cells with isotropic and anisotropic growth. Actual growth of the cell wall is simulated simultaneously with the mechanics. Methods The cell is considered as a closed, thin-walled structure, maintained in tension by turgor pressure. The cell walls are represented as linear elastic elements that obey Hooke's law. Cell expansion is induced by turgor pressure acting on the yielding cell-wall material. A system of differential equations for the positions and velocities of the cell vertices as well as for the actual growth of the cell wall is established. Readiness to divide is determined based on cell size. An ellipse-fitting algorithm is used to determine the position and orientation of the dividing wall. The cell vertices, walls and cell connectivity are then updated and cell expansion resumes. Comparisons are made with experimental data from the literature. Key Results The generic plant cell division algorithm has been implemented successfully. It can handle both symmetrically and asymmetrically dividing cells coupled with isotropic and anisotropic growth modes. Development of the algorithm highlighted the importance of ellipse-fitting to produce randomness (biological variability) even in symmetrically dividing cells. Unlike previous models, a differential equation is formulated for the resting length of the cell wall to simulate actual biological growth and is solved simultaneously with the position and velocity of the vertices. Conclusions The algorithm presented can produce different tissues varying in topological and geometrical properties. This flexibility to produce different tissue types gives the model great potential for use in investigations of plant cell division and growth in silico. PMID:24863687

IL-2 and Beyond in Cancer Immunotherapy.

PubMed

Wrangle, John M; Patterson, Alicia; Johnson, C Bryce; Neitzke, Daniel J; Mehrotra, Shikhar; Denlinger, Chadrick E; Paulos, Chrystal M; Li, Zihai; Cole, David J; Rubinstein, Mark P

2018-02-01

The development of the T- and natural killer (NK) cell growth factor IL-2 has been a sentinel force ushering in the era of immunotherapy in cancer. With the advent of clinical grade recombinant IL-2 in the mid-1980s, oncologists could for the first time directly manipulate lymphocyte populations with systemic therapy. By itself, recombinant IL-2 can induce clinical responses in up to 15% of patients with metastatic cancer or renal cell carcinoma. When administered with adoptively transferred tumor-reactive lymphocytes, IL-2 promotes T cell engraftment and response rates of up to 50% in metastatic melanoma patients. Importantly, these IL-2-driven responses can yield complete and durable responses in a subset of patients. However, the use of IL-2 is limited by toxicity and concern of the expansion of T regulatory cells. To overcome these limitations and improve response rates, other T cell growth factors, including IL-15 and modified forms of IL-2, are in clinical development. Administering T cell growth factors in combination with other agents, such as immune checkpoint pathway inhibitors, may also improve efficacy. In this study, we review the development of T- and NK cell growth factors and highlight current combinatorial approaches based on these reagents.

Differential Regulation of Mouse B Cell Development by Transforming Growth Factor β1

PubMed Central

Kaminski, Denise A.; Letterio, John J.; Burrows, Peter D.

2002-01-01

Transforming growth factor β (TGFβ) can inhibit the in vitro proliferation, survival and differentiation of B cell progenitors, mature B lymphocytes and plasma cells. Here we demonstrate unexpected, age-dependent reductions in the bone marrow (BM) B cell progenitors and immature B cells in TGFβ1-/- mice. To evaluate TGFβ responsiveness during normal B lineage development, cells were cultured in interleukin 7 (IL7)±TGFβ. Picomolar doses of TGFβ1 reduced pro-B cell recoveries at every timepoint. By contrast, the pre-B cells were initially reduced in number, but subsequently increased compared to IL7 alone, resulting in a 4-fold increase in the growth rate for the pre-B cell population. Analysis of purified BM sub-populations indicated that pro-B cells and the earliest BP1- pre-B cells were sensitive to the inhibitory effects of TGFβ1. However, the large BP1+ pre-B cells, although initially reduced, were increased in number at days 5 and 7 of culture. These results indicate that TGFβ1 is important for normal B cell development in vivo, and that B cell progenitors are differentially affected by the cytokine according to their stage of differentiation. PMID:12739785

Peptide hormones and lung cancer.

PubMed

Moody, T W

2006-03-01

Several peptide hormones have been identified which alter the proliferation of lung cancer. Small cell lung cancer (SCLC), which is a neuroendocrine cancer, produces and secretes gastrin releasing peptide (GRP), neurotensin (NT) and adrenomedullin (AM) as autocrine growth factors. GRP, NT and AM bind to G-protein coupled receptors causing phosphatidylinositol turnover or elevated cAMP in SCLC cells. Addition of GRP, NT or AM to SCLC cells causes altered expression of nuclear oncogenes, such as c-fos, and stimulation of growth. Antagonists have been developed for GRP, NT and AM receptors which function as cytostatic agents and inhibit SCLC growth. Growth factor antagonists, such as the NT1 receptor antagonist SR48692, facilitate the ability of chemotherapeutic drugs to kill lung cancer cells. It remains to be determined if GRP, NT and AM receptors will served as molecular targets, for development of new therapies for the treatment of SCLC patients. Non-small cell lung cancer (NSCLC) cells also have a high density of GRP, NT, AM and epidermal growth factor (EGF) receptors. Several NSCLC patients with EGF receptor mutations respond to gefitinib, a tyrosine kinase inhibitor. Gefitinib relieves NSCLC symptoms, maintaining stable disease in patients who are not eligible for systemic chemotherapy. It is important to develop new therapeutic approaches using translational research techniques for the treatment of lung cancer patients.

The long-term label retaining population of the renal papilla arises through divergent regional growth of the kidney.

PubMed

Adams, Derek C; Oxburgh, Leif

2009-09-01

Long-term pulse chase experiments previously identified a sizable population of BrdU-retaining cells within the renal papilla. The origin of these cells has been unclear, and in this work we test the hypothesis that they become quiescent early during the course of kidney development and organ growth. Indeed, we find that BrdU-retaining cells of the papilla can be labeled only by pulsing with BrdU from embryonic (E) day 11.25 to postnatal (P) day 7, the approximate period of kidney development in the mouse. BrdU signal in the cortex and outer medulla is rapidly diluted by cellular proliferation during embryonic development and juvenile growth, whereas cells within the papilla differentiate and exit the cell cycle during organogenesis. Indeed, by E17.5, little or no active proliferation can be seen in the distal papilla, indicating maturation of this structure in a distal-to-proximal manner during organogenesis. We conclude that BrdU-retaining cells of the papilla represent a population of cells that quiesce during embryonic development and localize within a region of the kidney that matures early. We therefore propose that selective papillary retention of BrdU arises through a combination of regionalized slowing of, and exit from, the cell cycle within the papilla during the period of ongoing kidney development, and extensive proliferative growth of the juvenile kidney resulting in dilution of BrdU below the detection level in extra-papillary regions.

Arabidopsis JAGGED links floral organ patterning to tissue growth by repressing Kip-related cell cycle inhibitors.

PubMed

Schiessl, Katharina; Muiño, Jose M; Sablowski, Robert

2014-02-18

Plant morphogenesis requires coordinated cytoplasmic growth, oriented cell wall extension, and cell cycle progression, but it is debated which of these processes are primary drivers for tissue growth and directly targeted by developmental genes. Here, we used ChIP high-throughput sequencing combined with transcriptome analysis to identify global target genes of the Arabidopsis transcription factor JAGGED (JAG), which promotes growth of the distal region of floral organs. Consistent with the roles of JAG during organ initiation and subsequent distal organ growth, we found that JAG directly repressed genes involved in meristem development, such as CLAVATA1 and HANABA TARANU, and genes involved in the development of the basal region of shoot organs, such as BLADE ON PETIOLE 2 and the GROWTH REGULATORY FACTOR pathway. At the same time, JAG regulated genes involved in tissue polarity, cell wall modification, and cell cycle progression. In particular, JAG directly repressed KIP RELATED PROTEIN 4 (KRP4) and KRP2, which control the transition to the DNA synthesis phase (S-phase) of the cell cycle. The krp2 and krp4 mutations suppressed jag defects in organ growth and in the morphology of petal epidermal cells, showing that the interaction between JAG and KRP genes is functionally relevant. Our work reveals that JAG is a direct mediator between genetic pathways involved in organ patterning and cellular functions required for tissue growth, and it shows that a regulatory gene shapes plant organs by releasing a constraint on S-phase entry.

CDP-Diacylglycerol Synthetase Coordinates Cell Growth and Fat Storage through Phosphatidylinositol Metabolism and the Insulin Pathway

PubMed Central

Liu, Yuan; Wang, Wei; Shui, Guanghou; Huang, Xun

2014-01-01

During development, animals usually undergo a rapid growth phase followed by a homeostatic stage when growth has ceased. The increase in cell size and number during the growth phase requires a large amount of lipids; while in the static state, excess lipids are usually stored in adipose tissues in preparation for nutrient-limited conditions. How cells coordinate growth and fat storage is not fully understood. Through a genetic screen we identified Drosophila melanogaster CDP-diacylglycerol synthetase (CDS/CdsA), which diverts phosphatidic acid from triacylglycerol synthesis to phosphatidylinositol (PI) synthesis and coordinates cell growth and fat storage. Loss of CdsA function causes significant accumulation of neutral lipids in many tissues along with reduced cell/organ size. These phenotypes can be traced back to reduced PI levels and, subsequently, low insulin pathway activity. Overexpressing CdsA rescues the fat storage and cell growth phenotypes of insulin pathway mutants, suggesting that CdsA coordinates cell/tissue growth and lipid storage through the insulin pathway. We also revealed that a DAG-to-PE route mediated by the choline/ethanolamine phosphotransferase Bbc may contribute to the growth of fat cells in CdsA RNAi. PMID:24603715

Growth and development after hematopoietic cell transplant in children.

PubMed

Sanders, J E

2008-01-01

Hematopoietic cell transplantation (HCT) following high-dose chemotherapy or chemoradiotherapy for children with malignant or nonmalignant hematologic disorders has resulted in an increasing number of long-term disease-free survivors. The preparative regimens include high doses of alkylating agents, such as CY with or without BU, and may include TBI. These agents impact the neuroendocrine system in growing children and their subsequent growth and development. Children receiving high-dose CY or BUCY have normal thyroid function, but those who receive TBI-containing regimens may develop thyroid function abnormalities. Growth is not impacted by chemotherapy-only preparative regimens, but TBI is likely to result in growth hormone deficiency and decreased growth rates that need to be treated with synthetic growth hormone therapy. Children who receive high-dose CY-only have normal development through puberty, whereas those who receive BUCY have a high incidence of delayed pubertal development. Following fractionated TBI preparative regimens, approximately half of the patients have normal pubertal development. These data demonstrate that the growth and development problems after HCT are dependent upon the preparative regimen received. All children should be followed for years after HCT for detection of growth and development abnormalities that are treatable with appropriate hormone therapy.

Cyclin A2 promotes DNA repair in the brain during both development and aging.

PubMed

Gygli, Patrick E; Chang, Joshua C; Gokozan, Hamza N; Catacutan, Fay P; Schmidt, Theresa A; Kaya, Behiye; Goksel, Mustafa; Baig, Faisal S; Chen, Shannon; Griveau, Amelie; Michowski, Wojciech; Wong, Michael; Palanichamy, Kamalakannan; Sicinski, Piotr; Nelson, Randy J; Czeisler, Catherine; Otero, José J

2016-07-01

Various stem cell niches of the brain have differential requirements for Cyclin A2. Cyclin A2 loss results in marked cerebellar dysmorphia, whereas forebrain growth is retarded during early embryonic development yet achieves normal size at birth. To understand the differential requirements of distinct brain regions for Cyclin A2, we utilized neuroanatomical, transgenic mouse, and mathematical modeling techniques to generate testable hypotheses that provide insight into how Cyclin A2 loss results in compensatory forebrain growth during late embryonic development. Using unbiased measurements of the forebrain stem cell niche, we parameterized a mathematical model whereby logistic growth instructs progenitor cells as to the cell-types of their progeny. Our data was consistent with prior findings that progenitors proliferate along an auto-inhibitory growth curve. The growth retardation inCCNA2-null brains corresponded to cell cycle lengthening, imposing a developmental delay. We hypothesized that Cyclin A2 regulates DNA repair and that CCNA2-null progenitors thus experienced lengthened cell cycle. We demonstrate that CCNA2-null progenitors suffer abnormal DNA repair, and implicate Cyclin A2 in double-strand break repair. Cyclin A2's DNA repair functions are conserved among cell lines, neural progenitors, and hippocampal neurons. We further demonstrate that neuronal CCNA2 ablation results in learning and memory deficits in aged mice.

Applications of Microscale Technologies for Regenerative Dentistry

PubMed Central

Hacking, S.A.; Khademhosseini, A.

2009-01-01

While widespread advances in tissue engineering have occurred over the past decade, many challenges remain in the context of tissue engineering and regeneration of the tooth. For example, although tooth development is the result of repeated temporal and spatial interactions between cells of ectoderm and mesoderm origin, most current tooth engineering systems cannot recreate such developmental processes. In this regard, microscale approaches that spatially pattern and support the development of different cell types in close proximity can be used to regulate the cellular microenvironment and, as such, are promising approaches for tooth development. Microscale technologies also present alternatives to conventional tissue engineering approaches in terms of scaffolds and the ability to direct stem cells. Furthermore, microscale techniques can be used to miniaturize many in vitro techniques and to facilitate high-throughput experimentation. In this review, we discuss the emerging microscale technologies for the in vitro evaluation of dental cells, dental tissue engineering, and tooth regeneration. Abbreviations: AS, adult stem cell; BMP, bone morphogenic protein; ECM, extracellular matrix; ES, embryonic stem cell; HA, hydroxyapatite; FGF-2, fibroblast growth factor; iPS, inducible pleuripotent stem cell; IGF-1, insulin-like growth factor; PDGF, platelet-derived growth factor; PDMS, poly(dimethylsiloxane); PGA, polyglycolate; PGS, polyglycerol sebacate; PLGA, poly-L-lactate-co-glycolate; PLL, poly-L-lactate; RGD, Arg-Gly-Asp attachment site; TCP, tricalcium phosphate; TGF-β, transforming growth factor beta; and VEGF, vascular endothelial growth factor. PMID:19493883

Activity of insulin growth factors and shrimp neurosecretory organ extracts on a lepidopteran cell line.

PubMed

Hatt, P J; Liebon, C; Morinière, M; Oberlander, H; Porcheron, P

1997-01-01

Ecdysteroids, or molting hormones, have been proven to be key differentiation regulators for epidermal cells in the postembryonic development of arthropods. Regulators of cell proliferation, however, remain largely unknown. To date, no diffusible insect peptidic growth factors have been characterized. Molecules structurally related to insulin have been discovered in insects, as in other eucaryotes. We developed in vitro tests for the preliminary characterization of potential growth factors in arthropods by adapting the procedures designed to detect such factors in vertebrates to an insect cell line (IAL-PID2) established from imaginal discs of the Indian meal moth. We verified the ability of these tests to measure the proliferation of IAL-PID2 cells. We tested mammalian insulin and insulin-like growth factors (IGF-I, IGF-II). Following an arrest of cell proliferation by serum deprivation, IGF-I and IGF-II caused partial resumption of the cell cycle, evidenced by DNA synthesis. In contrast, the addition of 20-hydroxyecdysone arrested the proliferation of the IAL-PID2 cells. The cell line was then used in a test for functional characterization of potential growth factors originating from the penaeid shrimp, Penaeus vannamei. Crude extracts of neurosecretory and nervous tissues, eyestalks, and ventral neural chain compensated for serum deprivation and stimulated completion of mitosis. Arch.

Growth and development of the root apical meristem.

PubMed

Perilli, Serena; Di Mambro, Riccardo; Sabatini, Sabrina

2012-02-01

A key question in plant developmental biology is how cell division and cell differentiation are balanced to modulate organ growth and shape organ size. In recent years, several advances have been made in understanding how this balance is achieved during root development. In the Arabidopsis root meristem, stem cells in the apical region of the meristem self-renew and produce daughter cells that differentiate in the distal meristem transition zone. Several factors have been implicated in controlling the different functional zones of the root meristem to modulate root growth; among these, plant hormones have been shown to play a main role. In this review, we summarize recent findings regarding the role of hormone signaling and transcriptional networks in regulating root development. Copyright © 2011 Elsevier Ltd. All rights reserved.

Muscle Stem Cells Undergo Extensive Clonal Drift during Tissue Growth via Meox1-Mediated Induction of G2 Cell-Cycle Arrest.

PubMed

Nguyen, Phong Dang; Gurevich, David Baruch; Sonntag, Carmen; Hersey, Lucy; Alaei, Sara; Nim, Hieu Tri; Siegel, Ashley; Hall, Thomas Edward; Rossello, Fernando Jaime; Boyd, Sarah Elizabeth; Polo, Jose Maria; Currie, Peter David

2017-07-06

Organ growth requires a careful balance between stem cell self-renewal and lineage commitment to ensure proper tissue expansion. The cellular and molecular mechanisms that mediate this balance are unresolved in most organs, including skeletal muscle. Here we identify a long-lived stem cell pool that mediates growth of the zebrafish myotome. This population exhibits extensive clonal drift, shifting from random deployment of stem cells during development to reliance on a small number of dominant clones to fuel the vast majority of muscle growth. This clonal drift requires Meox1, a homeobox protein that directly inhibits the cell-cycle checkpoint gene ccnb1. Meox1 initiates G 2 cell-cycle arrest within muscle stem cells, and disrupting this G 2 arrest causes premature lineage commitment and the resulting defects in muscle growth. These findings reveal that distinct regulatory mechanisms orchestrate stem cell dynamics during organ growth, beyond the G 0 /G 1 cell-cycle inhibition traditionally associated with maintaining tissue-resident stem cells. Copyright © 2017. Published by Elsevier Inc.

Cell division and turgor mediate enhanced plant growth in Arabidopsis plants treated with the bacterial signalling molecule lumichrome.

PubMed

Pholo, Motlalepula; Coetzee, Beatrix; Maree, Hans J; Young, Philip R; Lloyd, James R; Kossmann, Jens; Hills, Paul N

2018-05-17

Transcriptomic analysis indicates that the bacterial signalling molecule lumichrome enhances plant growth through a combination of enhanced cell division and cell enlargement, and possibly enhances photosynthesis. Lumichrome (7,8 dimethylalloxazine), a novel multitrophic signal molecule produced by Sinorhizobium meliloti bacteria, has previously been shown to elicit growth promotion in different plant species (Phillips et al. in Proc Natl Acad Sci USA 96:12275-12280, https://doi.org/10.1073/pnas.96.22.12275 , 1999). However, the molecular mechanisms that underlie this plant growth promotion remain obscure. Global transcript profiling using RNA-seq suggests that lumichrome enhances growth by inducing genes impacting on turgor driven growth and mitotic cell cycle that ensures the integration of cell division and expansion of developing leaves. The abundance of XTH9 and XPA4 transcripts was attributed to improved mediation of cell-wall loosening to allow turgor-driven cell enlargement. Mitotic CYCD3.3, CYCA1.1, SP1L3, RSW7 and PDF1 transcripts were increased in lumichrome-treated Arabidopsis thaliana plants, suggesting enhanced growth was underpinned by increased cell differentiation and expansion with a consequential increase in biomass. Synergistic ethylene-auxin cross-talk was also observed through reciprocal over-expression of ACO1 and SAUR54, in which ethylene activates the auxin signalling pathway and regulates Arabidopsis growth by both stimulating auxin biosynthesis and modulating the auxin transport machinery to the leaves. Decreased transcription of jasmonate biosynthesis and responsive-related transcripts (LOX2; LOX3; LOX6; JAL34; JR1) might contribute towards suppression of the negative effects of methyl jasmonate (MeJa) such as chlorophyll loss and decreases in RuBisCO and photosynthesis. This work contributes towards a deeper understanding of how lumichrome enhances plant growth and development.

Temporal Control of Transforming Growth Factor (TGF) - Betal Expression on Mammary Cell Multistep Transformation

DTIC Science & Technology

1999-10-01

deregulated cell mors and may eventually regress through growth (18). The importance of APC and 0- cat - apoptosis (25). enin in the development of colorectal...progression. In support of this idea, Torre Amione et al. [74] demonstrated that, unlike parental tumor cells, fibrosarcoma cells transfected to express 10

CYCD3 D-type cyclins regulate cambial cell proliferation and secondary growth in Arabidopsis

PubMed Central

Collins, Carl; Maruthi, N. M.; Jahn, Courtney E.

2015-01-01

A major proportion of plant biomass is derived from the activity of the cambium, a lateral meristem responsible for vascular tissue formation and radial organ enlargement in a process termed secondary growth. In contrast to our relatively good understanding of the regulation of primary meristems, remarkably little is known concerning the mechanisms controlling secondary growth, particularly how cambial cell divisions are regulated and integrated with vascular differentiation. A genetic loss-of-function approach was used here to reveal a rate-limiting role for the Arabidopsis CYCLIN D3 (CYCD3) subgroup of cell-cycle genes in the control of cambial cell proliferation and secondary growth, providing conclusive evidence of a direct link between the cell cycle and vascular development. It is shown that all three CYCD3 genes are specifically expressed in the cambium throughout vascular development. Analysis of a triple loss-of-function CYCD3 mutant revealed a requirement for CYCD3 in promoting the cambial cell cycle since mutant stems and hypocotyls showed a marked reduction in diameter linked to reduced mitotic activity in the cambium. Conversely, loss of CYCD3 provoked an increase in xylem cell size and the expression of differentiation markers, showing that CYCD3 is required to restrain the differentiation of xylem precursor cells. Together, our data show that tight control of cambial cell division through developmental- and cell type-specific regulation of CYCD3 is required for normal vascular development, constituting part of a novel mechanism controlling organ growth in higher plants. PMID:26022252

Characterization of dependencies between growth and division in budding yeast

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mayhew, Michael B.; Iversen, Edwin S.; Hartemink, Alexander J.

Cell growth and division are processes vital to the proliferation and development of life. Coordination between these two processes has been recognized for decades in a variety of organisms. In the budding yeast Saccharomyces cerevisiae, this coordination or ‘size control’ appears as an inverse correlation between cell size and the rate of cell-cycle progression, routinely observed in G1 prior to cell division commitment. Beyond this point, cells are presumed to complete S/G 2/M at similar rates and in a size-independent manner. As such, studies of dependence between growth and division have focused on G1. Moreover, in unicellular organisms, coordination betweenmore » growth and division has commonly been analyzed within the cycle of a single cell without accounting for correlations in growth and division characteristics between cycles of related cells. In a comprehensive analysis of three published time-lapse microscopy datasets, we analyze both intra- and inter-cycle dependencies between growth and division, revisiting assumptions about the coordination between these two processes. Interestingly, we find evidence (1) that S/G 2/M durations are systematically longer in daughters than in mothers, (2) of dependencies between S/G2/M and size at budding that echo the classical G1 dependencies, and, (3) in contrast with recent bacterial studies, of negative dependencies between size at birth and size accumulated during the cell cycle. In addition, we develop a novel hierarchical model to uncover inter-cycle dependencies, and we find evidence for such dependencies in cells growing in sugar-poor environments. Our analysis highlights the need for experimentalists and modelers to account for new sources of cell-to-cell variation in growth and division, and our model provides a formal statistical framework for the continued study of dependencies between biological processes.« less

Characterization of dependencies between growth and division in budding yeast

DOE PAGES

Mayhew, Michael B.; Iversen, Edwin S.; Hartemink, Alexander J.

2017-02-01

Cell growth and division are processes vital to the proliferation and development of life. Coordination between these two processes has been recognized for decades in a variety of organisms. In the budding yeast Saccharomyces cerevisiae, this coordination or ‘size control’ appears as an inverse correlation between cell size and the rate of cell-cycle progression, routinely observed in G1 prior to cell division commitment. Beyond this point, cells are presumed to complete S/G 2/M at similar rates and in a size-independent manner. As such, studies of dependence between growth and division have focused on G1. Moreover, in unicellular organisms, coordination betweenmore » growth and division has commonly been analyzed within the cycle of a single cell without accounting for correlations in growth and division characteristics between cycles of related cells. In a comprehensive analysis of three published time-lapse microscopy datasets, we analyze both intra- and inter-cycle dependencies between growth and division, revisiting assumptions about the coordination between these two processes. Interestingly, we find evidence (1) that S/G 2/M durations are systematically longer in daughters than in mothers, (2) of dependencies between S/G2/M and size at budding that echo the classical G1 dependencies, and, (3) in contrast with recent bacterial studies, of negative dependencies between size at birth and size accumulated during the cell cycle. In addition, we develop a novel hierarchical model to uncover inter-cycle dependencies, and we find evidence for such dependencies in cells growing in sugar-poor environments. Our analysis highlights the need for experimentalists and modelers to account for new sources of cell-to-cell variation in growth and division, and our model provides a formal statistical framework for the continued study of dependencies between biological processes.« less

Characterization of dependencies between growth and division in budding yeast

PubMed Central

Iversen, Edwin S.; Hartemink, Alexander J.

2017-01-01

Cell growth and division are processes vital to the proliferation and development of life. Coordination between these two processes has been recognized for decades in a variety of organisms. In the budding yeast Saccharomyces cerevisiae, this coordination or ‘size control’ appears as an inverse correlation between cell size and the rate of cell-cycle progression, routinely observed in G1 prior to cell division commitment. Beyond this point, cells are presumed to complete S/G2/M at similar rates and in a size-independent manner. As such, studies of dependence between growth and division have focused on G1. Moreover, in unicellular organisms, coordination between growth and division has commonly been analysed within the cycle of a single cell without accounting for correlations in growth and division characteristics between cycles of related cells. In a comprehensive analysis of three published time-lapse microscopy datasets, we analyse both intra- and inter-cycle dependencies between growth and division, revisiting assumptions about the coordination between these two processes. Interestingly, we find evidence (i) that S/G2/M durations are systematically longer in daughters than in mothers, (ii) of dependencies between S/G2/M and size at budding that echo the classical G1 dependencies, and (iii) in contrast with recent bacterial studies, of negative dependencies between size at birth and size accumulated during the cell cycle. In addition, we develop a novel hierarchical model to uncover inter-cycle dependencies, and we find evidence for such dependencies in cells growing in sugar-poor environments. Our analysis highlights the need for experimentalists and modellers to account for new sources of cell-to-cell variation in growth and division, and our model provides a formal statistical framework for the continued study of dependencies between biological processes. PMID:28228543

Characterization of dependencies between growth and division in budding yeast.

PubMed

Mayhew, Michael B; Iversen, Edwin S; Hartemink, Alexander J

2017-02-01

Cell growth and division are processes vital to the proliferation and development of life. Coordination between these two processes has been recognized for decades in a variety of organisms. In the budding yeast Saccharomyces cerevisiae , this coordination or 'size control' appears as an inverse correlation between cell size and the rate of cell-cycle progression, routinely observed in G 1 prior to cell division commitment. Beyond this point, cells are presumed to complete S/G 2 /M at similar rates and in a size-independent manner. As such, studies of dependence between growth and division have focused on G 1 Moreover, in unicellular organisms, coordination between growth and division has commonly been analysed within the cycle of a single cell without accounting for correlations in growth and division characteristics between cycles of related cells. In a comprehensive analysis of three published time-lapse microscopy datasets, we analyse both intra- and inter-cycle dependencies between growth and division, revisiting assumptions about the coordination between these two processes. Interestingly, we find evidence (i) that S/G 2 /M durations are systematically longer in daughters than in mothers, (ii) of dependencies between S/G 2 /M and size at budding that echo the classical G 1 dependencies, and (iii) in contrast with recent bacterial studies, of negative dependencies between size at birth and size accumulated during the cell cycle. In addition, we develop a novel hierarchical model to uncover inter-cycle dependencies, and we find evidence for such dependencies in cells growing in sugar-poor environments. Our analysis highlights the need for experimentalists and modellers to account for new sources of cell-to-cell variation in growth and division, and our model provides a formal statistical framework for the continued study of dependencies between biological processes. © 2017 The Author(s).

Expression of novel, putative stem cell markers in prepubertal and lactating mammary glands of bovine

USDA-ARS?s Scientific Manuscript database

Mammary stem cells (MaSC) are essential for growth and maintenance of the mammary epithelium. Two main phases of mammary growth include ductal elongation prior to puberty and lobulo-alveolar growth and development during pregnancy. Some studies have utilized morphological characteristics and retenti...

An Off-Lattice Hybrid Discrete-Continuum Model of Tumor Growth and Invasion

PubMed Central

Jeon, Junhwan; Quaranta, Vito; Cummings, Peter T.

2010-01-01

Abstract We have developed an off-lattice hybrid discrete-continuum (OLHDC) model of tumor growth and invasion. The continuum part of the OLHDC model describes microenvironmental components such as matrix-degrading enzymes, nutrients or oxygen, and extracellular matrix (ECM) concentrations, whereas the discrete portion represents individual cell behavior such as cell cycle, cell-cell, and cell-ECM interactions and cell motility by the often-used persistent random walk, which can be depicted by the Langevin equation. Using this framework of the OLHDC model, we develop a phenomenologically realistic and bio/physically relevant model that encompasses the experimentally observed superdiffusive behavior (at short times) of mammalian cells. When systemic simulations based on the OLHDC model are performed, tumor growth and its morphology are found to be strongly affected by cell-cell adhesion and haptotaxis. There is a combination of the strength of cell-cell adhesion and haptotaxis in which fingerlike shapes, characteristic of invasive tumor, are observed. PMID:20074513

Inducible growth mode switches influence Valonia rhizoid differentiation.

PubMed

Elvira, Paul Rommel; Sekida, Satoko; Okuda, Kazuo

2013-02-01

Cell differentiation and cell type commitment are an integral part of plant growth and development. Investigations on how environmental conditions affect the formation of shoots, roots, and rhizoids can help illustrate how plants determine cell fate and overall morphology. In this study, we evaluated the role of substratum and light on rhizoid differentiation in the coenocytic green alga, Valonia aegagropila. Elongating rhizoids displayed varying growth modes and cell shape upon exposure to different substrata and light conditions. It was found that soft substrata and dark incubation promoted rhizoid elongation via tip growth while subsequent exposure to light prevented tip growth and instead induced swelling in the apical region of rhizoids. Swelling was accompanied by the accumulation of protoplasm in the rhizoid tip through expansion of the cell wall and uninhibited cytoplasmic streaming. Subsequent diffuse growth led to the transformation from slender, rod-shaped rhizoids into spherical thallus-like structures that required photosynthesis. Further manipulation of light regimes caused vacillating cell growth redirections. An elongating V. aegagropila rhizoid cell thus appears capable of growth mode switching that is regulated by immediate environmental conditions thereby influencing ultimate cell shape and function. This is the first description of inducible, multiple growth mode shifts in a single intact plant cell that directly impact its differentiation.

Cell wall structures leading to cultivar differences in softening rates develop early during apple (Malus x domestica) fruit growth.

PubMed

Ng, Jovyn K T; Schröder, Roswitha; Sutherland, Paul W; Hallett, Ian C; Hall, Miriam I; Prakash, Roneel; Smith, Bronwen G; Melton, Laurence D; Johnston, Jason W

2013-11-19

There is a paucity of information regarding development of fruit tissue microstructure and changes in the cell walls during fruit growth, and how these developmental processes differ between cultivars with contrasting softening behaviour. In this study we compare two apple cultivars that show different softening rates during fruit development and ripening. We investigate whether these different softening behaviours manifest themselves late during ethylene-induced softening in the ripening phase, or early during fruit expansion and maturation. 'Scifresh' (slow softening) and 'Royal Gala' (rapid softening) apples show differences in cortical microstructure and cell adhesion as early as the cell expansion phase. 'Scifresh' apples showed reduced loss of firmness and greater dry matter accumulation compared with 'Royal Gala' during early fruit development, suggesting differences in resource allocation that influence tissue structural properties. Tricellular junctions in 'Scifresh' were rich in highly-esterified pectin, contributing to stronger cell adhesion and an increased resistance to the development of large airspaces during cell expansion. Consequently, mature fruit of 'Scifresh' showed larger, more angular shaped cells than 'Royal Gala', with less airspaces and denser tissue. Stronger cell adhesion in ripe 'Scifresh' resulted in tissue fracture by cell rupture rather than by cell-to-cell-separation as seen in 'Royal Gala'. CDTA-soluble pectin differed in both cultivars during development, implicating its involvement in cell adhesion. Low pectin methylesterase activity during early stages of fruit development coupled with the lack of immuno-detectable PG was associated with increased cell adhesion in 'Scifresh'. Our results indicate that cell wall structures leading to differences in softening rates of apple fruit develop early during fruit growth and well before the induction of the ripening process.

Cell wall structures leading to cultivar differences in softening rates develop early during apple (Malus x domestica) fruit growth

PubMed Central

2013-01-01

Background There is a paucity of information regarding development of fruit tissue microstructure and changes in the cell walls during fruit growth, and how these developmental processes differ between cultivars with contrasting softening behaviour. In this study we compare two apple cultivars that show different softening rates during fruit development and ripening. We investigate whether these different softening behaviours manifest themselves late during ethylene-induced softening in the ripening phase, or early during fruit expansion and maturation. Results ‘Scifresh’ (slow softening) and ‘Royal Gala’ (rapid softening) apples show differences in cortical microstructure and cell adhesion as early as the cell expansion phase. ‘Scifresh’ apples showed reduced loss of firmness and greater dry matter accumulation compared with ‘Royal Gala’ during early fruit development, suggesting differences in resource allocation that influence tissue structural properties. Tricellular junctions in ‘Scifresh’ were rich in highly-esterified pectin, contributing to stronger cell adhesion and an increased resistance to the development of large airspaces during cell expansion. Consequently, mature fruit of ‘Scifresh’ showed larger, more angular shaped cells than ‘Royal Gala’, with less airspaces and denser tissue. Stronger cell adhesion in ripe ‘Scifresh’ resulted in tissue fracture by cell rupture rather than by cell-to-cell-separation as seen in ‘Royal Gala’. CDTA-soluble pectin differed in both cultivars during development, implicating its involvement in cell adhesion. Low pectin methylesterase activity during early stages of fruit development coupled with the lack of immuno-detectable PG was associated with increased cell adhesion in ‘Scifresh’. Conclusions Our results indicate that cell wall structures leading to differences in softening rates of apple fruit develop early during fruit growth and well before the induction of the ripening process. PMID:24252512

Single-point ACT2 gene mutation in the Arabidopsis root hair mutant der1-3 affects overall actin organization, root growth and plant development.

PubMed

Vaškebová, L; Šamaj, J; Ovecka, M

2017-12-27

The actin cytoskeleton forms a dynamic network in plant cells. A single-point mutation in the DER1 (deformed root hairs1) locus located in the sequence of ACTIN2, a gene for major actin in vegetative tissues of Arabidopsis thaliana, leads to impaired root hair development (Ringli C, Baumberger N, Diet A, Frey B, Keller B. 2002. ACTIN2 is essential for bulge site selection and tip growth during root hair development of Arabidopsis. Plant Physiology129: 1464-1472). Only root hair phenotypes have been described so far in der1 mutants, but here we demonstrate obvious aberrations in the organization of the actin cytoskeleton and overall plant development. Organization of the actin cytoskeleton in epidermal cells of cotyledons, hypocotyls and roots was studied qualitatively and quantitatively by live-cell imaging of transgenic lines carrying the GFP-FABD2 fusion protein and in fixed cells after phalloidin labelling. Patterns of root growth were characterized by FM4-64 vital staining, light-sheet microscopy imaging and microtubule immunolabelling. Plant phenotyping included analyses of germination, root growth and plant biomass. Speed of germination, plant fresh weight and total leaf area were significantly reduced in the der1-3 mutant in comparison with the C24 wild-type. Actin filaments in root, hypocotyl and cotyledon epidermal cells of the der1-3 mutant were shorter, thinner and arranged in more random orientations, while actin bundles were shorter and had altered orientations. The wavy pattern of root growth in der1-3 mutant was connected with higher frequencies of shifted cell division planes (CDPs) in root cells, which was consistent with the shifted positioning of microtubule-based preprophase bands and phragmoplasts. The organization of cortical microtubules in the root cells of the der1-3 mutant, however, was not altered. Root growth rate of the der1-3 mutant is not reduced, but changes in the actin cytoskeleton organization can induce a wavy root growth pattern through deregulation of CDP orientation. The results suggest that the der1-3 mutation in the ACT2 gene does not influence solely root hair formation process, but also has more general effects on the actin cytoskeleton, plant growth and development. © The Author(s) 2017. Published by Oxford University Press on behalf of the Annals of Botany Company.

Axon growth regulation by a bistable molecular switch.

PubMed

Padmanabhan, Pranesh; Goodhill, Geoffrey J

2018-04-25

For the brain to function properly, its neurons must make the right connections during neural development. A key aspect of this process is the tight regulation of axon growth as axons navigate towards their targets. Neuronal growth cones at the tips of developing axons switch between growth and paused states during axonal pathfinding, and this switching behaviour determines the heterogeneous axon growth rates observed during brain development. The mechanisms controlling this switching behaviour, however, remain largely unknown. Here, using mathematical modelling, we predict that the molecular interaction network involved in axon growth can exhibit bistability, with one state representing a fast-growing growth cone state and the other a paused growth cone state. Owing to stochastic effects, even in an unchanging environment, model growth cones reversibly switch between growth and paused states. Our model further predicts that environmental signals could regulate axon growth rate by controlling the rates of switching between the two states. Our study presents a new conceptual understanding of growth cone switching behaviour, and suggests that axon guidance may be controlled by both cell-extrinsic factors and cell-intrinsic growth regulatory mechanisms. © 2018 The Author(s).

Dally Proteoglycan Mediates the Autonomous and Nonautonomous Effects on Tissue Growth Caused by Activation of the PI3K and TOR Pathways

PubMed Central

Ferreira, Ana; Milán, Marco

2015-01-01

How cells acquiring mutations in tumor suppressor genes outcompete neighboring wild-type cells is poorly understood. The phosphatidylinositol 3-kinase (PI3K)–phosphatase with tensin homology (PTEN) and tuberous sclerosis complex (TSC)-target of rapamycin (TOR) pathways are frequently activated in human cancer, and this activation is often causative of tumorigenesis. We utilized the Gal4-UAS system in Drosophila imaginal primordia, highly proliferative and growing tissues, to analyze the impact of restricted activation of these pathways on neighboring wild-type cell populations. Activation of these pathways leads to an autonomous induction of tissue overgrowth and to a remarkable nonautonomous reduction in growth and proliferation rates of adjacent cell populations. This nonautonomous response occurs independently of where these pathways are activated, is functional all throughout development, takes place across compartments, and is distinct from cell competition. The observed autonomous and nonautonomous effects on tissue growth rely on the up-regulation of the proteoglycan Dally, a major element involved in modulating the spreading, stability, and activity of the growth promoting Decapentaplegic (Dpp)/transforming growth factor β(TGF-β) signaling molecule. Our findings indicate that a reduction in the amount of available growth factors contributes to the outcompetition of wild-type cells by overgrowing cell populations. During normal development, the PI3K/PTEN and TSC/TOR pathways play a major role in sensing nutrient availability and modulating the final size of any developing organ. We present evidence that Dally also contributes to integrating nutrient sensing and organ scaling, the fitting of pattern to size. PMID:26313758

Decreasing CNPY2 Expression Diminishes Colorectal Tumor Growth and Development through Activation of p53 Pathway.

PubMed

Yan, Ping; Gong, Hui; Zhai, Xiaoyan; Feng, Yi; Wu, Jun; He, Sheng; Guo, Jian; Wang, Xiaoxia; Guo, Rui; Xie, Jun; Li, Ren-Ke

2016-04-01

Neovascularization drives tumor development, and angiogenic factors are important neovascularization initiators. We recently identified the secreted angiogenic factor CNPY2, but its involvement in cancer has not been explored. Herein, we investigate CNPY2's role in human colorectal cancer (CRC) development. Tumor samples were obtained from CRC patients undergoing surgery. Canopy 2 (CNPY2) expression was analyzed in tumor and adjacent normal tissue. Stable lines of human HCT116 cells expressing CNPY2 shRNA or control shRNA were established. To determine CNPY2's effects on tumor xenografts in vivo, human CNPY2 shRNA HCT116 cells and controls were injected into nude mice, separately. Cellular apoptosis, growth, and angiogenesis in the xenografts were evaluated. CNPY2 expression was significantly higher in CRC tissues. CNPY2 knockdown in HCT116 cells inhibited growth and migration and promoted apoptosis. In xenografts, CNPY2 knockdown prevented tumor growth and angiogenesis and promoted apoptosis. Knockdown of CNPY2 in the HCT116 CRC cell line reversibly increased p53 activity. The p53 activation increased cyclin-dependent kinase inhibitor p21 and decreased cyclin-dependent kinase 2, thereby inhibiting tumor cell growth, inducing cell apoptosis, and reducing angiogenesis both in vitro and in vivo. CNPY2 may play a critical role in CRC development by enhancing cell proliferation, migration, and angiogenesis and by inhibiting apoptosis through negative regulation of the p53 pathway. Therefore, CNPY2 may represent a novel CRC therapeutic target and prognostic indicator. Copyright © 2016 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Computational modelling of the scaffold-free chondrocyte regeneration: a two-way coupling between the cell growth and local fluid flow and nutrient concentration.

PubMed

Hossain, Md Shakhawath; Bergstrom, D J; Chen, X B

2015-11-01

The in vitro chondrocyte cell culture process in a perfusion bioreactor provides enhanced nutrient supply as well as the flow-induced shear stress that may have a positive influence on the cell growth. Mathematical and computational modelling of such a culture process, by solving the coupled flow, mass transfer and cell growth equations simultaneously, can provide important insight into the biomechanical environment of a bioreactor and the related cell growth process. To do this, a two-way coupling between the local flow field and cell growth is required. Notably, most of the computational and mathematical models to date have not taken into account the influence of the cell growth on the local flow field and nutrient concentration. The present research aimed at developing a mathematical model and performing a numerical simulation using the lattice Boltzmann method to predict the chondrocyte cell growth without a scaffold on a flat plate placed inside a perfusion bioreactor. The model considers the two-way coupling between the cell growth and local flow field, and the simulation has been performed for 174 culture days. To incorporate the cell growth into the model, a control-volume-based surface growth modelling approach has been adopted. The simulation results show the variation of local fluid velocity, shear stress and concentration distribution during the culture period due to the growth of the cell phase and also illustrate that the shear stress can increase the cell volume fraction to a certain extent.

Purification and cultivation of human pituitary growth hormone secreting cells

NASA Technical Reports Server (NTRS)

Hymer, W. C.

1978-01-01

The maintainance of actively secreting human pituitary growth hormone cells (somatotrophs) in vitro was studied. The primary approach was the testing of agents which may be expected to increase the release of the human growth hormone (hGH). A procedure for tissue procurement is described along with the methodologies used to dissociate human pituitary tissue (obtained either at autopsy or surgery) into single cell suspensions. The validity of the Biogel cell column perfusion system for studying the dynamics of GH release was developed and documented using a rat pituitary cell system.

The AINTEGUMENTA genes, MdANT1 and MdANT2, are associated with the regulation of cell production during fruit growth in apple (Malus × domestica Borkh.)

PubMed Central

2012-01-01

Background Fruit growth in apple (Malus × domestica Borkh.) is mediated by cell production and expansion. Genes involved in regulating these processes and thereby fruit growth, are not well characterized. We hypothesized that the apple homolog(s) of AINTEGUMENTA (ANT), an APETALA2–repeat containing transcription factor, regulates cell production during fruit growth in apple. Results Two ANT genes, MdANT1 and MdANT2, were isolated from apple and their expression was studied during multiple stages of fruit development. MdANT1 and MdANT2 expression was high during early fruit growth coincident with the period of cell production, rapidly declined during exit from cell production, and remained low during the rest of fruit development. The effects of increase in carbohydrate availability during fruit growth were characterized. Increase in carbohydrate availability enhanced fruit growth largely through an increase in cell production. Expression of MdANT1 and MdANT2 increased sharply by up to around 5-fold in response to an increase in carbohydrate availability. Expression of the ANT genes was compared across two apple genotypes, ‘Gala’ and ‘Golden Delicious Smoothee’ (GS), which differ in the extent of fruit growth, largely due to differences in cell production. In comparison to ‘Gala’, the larger fruit-size genotype, GS, displayed higher levels and a longer duration of MdANT1 and MdANT2 expression. Expression of the ANTs and cell cycle genes in the fruit core and cortex tissues isolated using laser capture microdissection was studied. During early fruit growth, expression of the MdANTs was higher within the cortex, the tissue that constitutes the majority of the fruit. Additionally, MdANT1 and MdANT2 expression was positively correlated with that of A- and B-type CYCLINS, B-type CYCLIN-DEPENDENT-KINASES (CDKBs) and MdDEL1. Conclusions Multiple lines of evidence from this study suggest that MdANT1 and MdANT2 regulate cell production during fruit growth in apple. ANTs may coordinate the expression of cell proliferation genes and thereby affect the competence of cells for cell production during fruit growth. Together, data from this study implicate MdANT1 and MdANT2 in the regulation of fruit growth in apple. PMID:22731507

The AINTEGUMENTA genes, MdANT1 and MdANT2, are associated with the regulation of cell production during fruit growth in apple (Malus × domestica Borkh.).

PubMed

Dash, Madhumita; Malladi, Anish

2012-06-25

Fruit growth in apple (Malus × domestica Borkh.) is mediated by cell production and expansion. Genes involved in regulating these processes and thereby fruit growth, are not well characterized. We hypothesized that the apple homolog(s) of AINTEGUMENTA (ANT), an APETALA2-repeat containing transcription factor, regulates cell production during fruit growth in apple. Two ANT genes, MdANT1 and MdANT2, were isolated from apple and their expression was studied during multiple stages of fruit development. MdANT1 and MdANT2 expression was high during early fruit growth coincident with the period of cell production, rapidly declined during exit from cell production, and remained low during the rest of fruit development. The effects of increase in carbohydrate availability during fruit growth were characterized. Increase in carbohydrate availability enhanced fruit growth largely through an increase in cell production. Expression of MdANT1 and MdANT2 increased sharply by up to around 5-fold in response to an increase in carbohydrate availability. Expression of the ANT genes was compared across two apple genotypes, 'Gala' and 'Golden Delicious Smoothee' (GS), which differ in the extent of fruit growth, largely due to differences in cell production. In comparison to 'Gala', the larger fruit-size genotype, GS, displayed higher levels and a longer duration of MdANT1 and MdANT2 expression. Expression of the ANTs and cell cycle genes in the fruit core and cortex tissues isolated using laser capture microdissection was studied. During early fruit growth, expression of the MdANTs was higher within the cortex, the tissue that constitutes the majority of the fruit. Additionally, MdANT1 and MdANT2 expression was positively correlated with that of A- and B-type CYCLINS, B-type CYCLIN-DEPENDENT-KINASES (CDKBs) and MdDEL1. Multiple lines of evidence from this study suggest that MdANT1 and MdANT2 regulate cell production during fruit growth in apple. ANTs may coordinate the expression of cell proliferation genes and thereby affect the competence of cells for cell production during fruit growth. Together, data from this study implicate MdANT1 and MdANT2 in the regulation of fruit growth in apple.

Spatial Regulation of Root Growth: Placing the Plant TOR Pathway in a Developmental Perspective

PubMed Central

Barrada, Adam; Montané, Marie-Hélène; Robaglia, Christophe; Menand, Benoît

2015-01-01

Plant cells contain specialized structures, such as a cell wall and a large vacuole, which play a major role in cell growth. Roots follow an organized pattern of development, making them the organs of choice for studying the spatio-temporal regulation of cell proliferation and growth in plants. During root growth, cells originate from the initials surrounding the quiescent center, proliferate in the division zone of the meristem, and then increase in length in the elongation zone, reaching their final size and differentiation stage in the mature zone. Phytohormones, especially auxins and cytokinins, control the dynamic balance between cell division and differentiation and therefore organ size. Plant growth is also regulated by metabolites and nutrients, such as the sugars produced by photosynthesis or nitrate assimilated from the soil. Recent literature has shown that the conserved eukaryotic TOR (target of rapamycin) kinase pathway plays an important role in orchestrating plant growth. We will summarize how the regulation of cell proliferation and cell expansion by phytohormones are at the heart of root growth and then discuss recent data indicating that the TOR pathway integrates hormonal and nutritive signals to orchestrate root growth. PMID:26295391

Mechanical activation of mammalian target of rapamycin pathway is required for cartilage development

PubMed Central

Guan, Yingjie; Yang, Xu; Yang, Wentian; Charbonneau, Cherie; Chen, Qian

2014-01-01

Mechanical stress regulates development by modulating cell signaling and gene expression. However, the cytoplasmic components mediating mechanotransduction remain unclear. In this study, elimination of muscle contraction during chicken embryonic development resulted in a reduction in the activity of mammalian target of rapamycin (mTOR) in the cartilaginous growth plate. Inhibition of mTOR activity led to significant inhibition of chondrocyte proliferation, cartilage tissue growth, and expression of chondrogenic genes, including Indian hedgehog (Ihh), a critical mediator of mechanotransduction. Conversely, cyclic loading (1 Hz, 5% matrix deformation) of embryonic chicken growth plate chondrocytes in 3-dimensional (3D) collagen scaffolding induced sustained activation of mTOR. Mechanical activation of mTOR occurred in serum-free medium, indicating that it is independent of growth factor or nutrients. Treatment of chondrocytes with Rapa abolished mechanical activation of cell proliferation and Ihh gene expression. Cyclic loading of chondroprogenitor cells deficient in SH2-containing protein tyrosine phosphatase 2 (Shp2) further enhanced mechanical activation of mTOR, cell proliferation, and chondrogenic gene expression. This result suggests that Shp2 is an antagonist of mechanotransduction through inhibition of mTOR activity. Our data demonstrate that mechanical activation of mTOR is necessary for cell proliferation, chondrogenesis, and cartilage growth during bone development, and that mTOR is an essential mechanotransduction component modulated by Shp2 in the cytoplasm.—Guan, Y., Yang, X., Yang, W., Charbonneau, C., Chen, Q. Mechanical activation of mammalian target of rapamycin pathway is required for cartilage development. PMID:25002119

Role of caspase-9 in the effector caspases and genome expressions, and growth of bovine skeletal myoblasts.

PubMed

Van Ba, Hoa; Hwang, Inho

2014-02-01

Caspase-9 has been reported as the key regulator of apoptosis, however, its role in skeletal myoblast development and molecular involvements during cell growth still remains unknown. The current study aimed to present the key role of caspase-9 in the expressions of apoptotic caspases and genome, and cell viability during myoblast growth using RNA interference mediated silencing. Three small interference RNA sequences (siRNAs) targeting caspase-9 gene was designed and ligated into pSilencer plasmid vector to construct shRNA expression constructs. Cells were transfected with the constructs for 48 h. Results indicated that all three siRNAs could silence the caspase-9 mRNA expression significantly. Particularly, the mRNA expression level of caspase-9 in the cells transfected by shRNA1, shRNA2 and shRNA3 constructs were reduced by 37.85%, 68.20% and 58.14%, respectively. Suppression of caspase-9 led to the significant increases in the mRNA and protein expressions of effector caspase-3, whereas the reduction in mRNA and protein expressions of caspase-7. The microarray results showed that the suppression of caspase-9 resulted in significant upregulations of cell proliferation-, adhesion-, growth-, development- and division-regulating genes, whereas the reduction in the expressions of cell death program- and stress response-regulating genes. Furthermore, cell viability was significantly increased following the transfection. These data suggest that caspase-9 could play an important role in the control of cell growth, and knockdown of caspase-9 may have genuine potential in the treatment of skeletal muscle atrophy. © 2013 The Authors Development, Growth & Differentiation © 2013 Japanese Society of Developmental Biologists.

Hypothyroidism in utero stimulates pancreatic beta cell proliferation and hyperinsulinaemia in the ovine fetus during late gestation.

PubMed

Harris, Shelley E; De Blasio, Miles J; Davis, Melissa A; Kelly, Amy C; Davenport, Hailey M; Wooding, F B Peter; Blache, Dominique; Meredith, David; Anderson, Miranda; Fowden, Abigail L; Limesand, Sean W; Forhead, Alison J

2017-06-01

Thyroid hormones are important regulators of growth and maturation before birth, although the extent to which their actions are mediated by insulin and the development of pancreatic beta cell mass is unknown. Hypothyroidism in fetal sheep induced by removal of the thyroid gland caused asymmetric organ growth, increased pancreatic beta cell mass and proliferation, and was associated with increased circulating concentrations of insulin and leptin. In isolated fetal sheep islets studied in vitro, thyroid hormones inhibited beta cell proliferation in a dose-dependent manner, while high concentrations of insulin and leptin stimulated proliferation. The developing pancreatic beta cell is therefore sensitive to thyroid hormone, insulin and leptin before birth, with possible consequences for pancreatic function in fetal and later life. The findings of this study highlight the importance of thyroid hormones during pregnancy for normal development of the fetal pancreas. Development of pancreatic beta cell mass before birth is essential for normal growth of the fetus and for long-term control of carbohydrate metabolism in postnatal life. Thyroid hormones are also important regulators of fetal growth, and the present study tested the hypotheses that thyroid hormones promote beta cell proliferation in the fetal ovine pancreatic islets, and that growth retardation in hypothyroid fetal sheep is associated with reductions in pancreatic beta cell mass and circulating insulin concentration in utero. Organ growth and pancreatic islet cell proliferation and mass were examined in sheep fetuses following removal of the thyroid gland in utero. The effects of triiodothyronine (T 3 ), insulin and leptin on beta cell proliferation rates were determined in isolated fetal ovine pancreatic islets in vitro. Hypothyroidism in the sheep fetus resulted in an asymmetric pattern of organ growth, pancreatic beta cell hyperplasia, and elevated plasma insulin and leptin concentrations. In pancreatic islets isolated from intact fetal sheep, beta cell proliferation in vitro was reduced by T 3 in a dose-dependent manner and increased by insulin at high concentrations only. Leptin induced a bimodal response whereby beta cell proliferation was suppressed at the lowest, and increased at the highest, concentrations. Therefore, proliferation of beta cells isolated from the ovine fetal pancreas is sensitive to physiological concentrations of T 3 , insulin and leptin. Alterations in these hormones may be responsible for the increased beta cell proliferation and mass observed in the hypothyroid sheep fetus and may have consequences for pancreatic function in later life. © 2017 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

Bioelectrochemical control of neural cell development on conducting polymers.

PubMed

Collazos-Castro, Jorge E; Polo, José L; Hernández-Labrado, Gabriel R; Padial-Cañete, Vanesa; García-Rama, Concepción

2010-12-01

Electrically conducting polymers hold promise for developing advanced neuroprostheses, bionic systems and neural repair devices. Among them, poly(3, 4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) exhibits superior physicochemical properties but biocompatibility issues have limited its use. We describe combinations of electrochemical and molecule self-assembling methods to consistently control neural cell development on PEDOT:PSS while maintaining very low interfacial impedance. Electro-adsorbed polylysine enabled long-term neuronal survival and growth on the nanostructured polymer. Neurite extension was strongly inhibited by an additional layer of PSS or heparin, which in turn could be either removed electrically or further coated with spermine to activate cell growth. Binding basic fibroblast growth factor (bFGF) to the heparin layer inhibited neurons but promoted proliferation and migration of precursor cells. This methodology may orchestrate neural cell behavior on electroactive polymers, thus improving cell/electrode communication in prosthetic devices and providing a platform for tissue repair strategies. Copyright © 2010 Elsevier Ltd. All rights reserved.

Differential Growth in Periclinal and Anticlinal Walls during Lobe Formation in Arabidopsis Cotyledon Pavement Cells

PubMed Central

Barton, Deborah A.; Law, Andrew M.K.; Overall, Robyn L.

2015-01-01

Lobe development in the epidermal pavement cells of Arabidopsis thaliana cotyledons and leaves is thought to take place via tip-like growth on the concave side of lobes driven by localized concentrations of actin filaments and associated proteins, with a predicted role for cortical microtubules in establishing the direction of restricted growth at the convex side. We used homologous landmarks fixed to the outer walls of pavement cells and thin-plate spline analysis to demonstrate that lobes form by differential growth of both the anticlinal and periclinal walls. Most lobes formed within the first 24 h of the cotyledons unfurling, during the period of rapid cell expansion. Cortical microtubules adjacent to the periclinal wall were persistently enriched at the convex side of lobes during development where growth was anisotropic and were less concentrated or absent at the concave side where growth was promoted. Alternating microtubule-enriched and microtubule-free zones at the periclinal wall in neighboring cells predicted sites of new lobes. There was no particular arrangement of cortical actin filaments that could predict where lobes would form. However, drug studies demonstrate that both filamentous actin and microtubules are required for lobe formation. PMID:26296967

The Big Bang of tissue growth: Apical cell constriction turns into tissue expansion.

PubMed

Janody, Florence

2018-03-05

How tissue growth is regulated during development and cancer is a fundamental question in biology. In this issue, Tsoumpekos et al. (2018. J. Cell Biol. https://doi.org/10.1083/jcb.201705104) and Forest et al. (2018. J. Cell Biol. https://doi.org/10.1083/jcb.201705107) identify Big bang (Bbg) as an important growth regulator of the Drosophila melanogaster wing imaginal disc. © 2018 Janody.

Antitumor activity of cytotoxic T lymphocytes engineered to target vascular endothelial growth factor receptors

NASA Astrophysics Data System (ADS)

Niederman, Thomas M. J.; Ghogawala, Zoher; Carter, Bob S.; Tompkins, Hillary S.; Russell, Margaret M.; Mulligan, Richard C.

2002-05-01

The demonstration that angiogenesis is required for the growth of solid tumors has fueled an intense interest in the development of new therapeutic strategies that target the tumor vasculature. Here we report the development of an immune-based antiangiogenic strategy that is based on the generation of T lymphocytes that possess a killing specificity for cells expressing vascular endothelial growth factor receptors (VEGFRs). To target VEGFR-expressing cells, recombinant retroviral vectors were generated that encoded a chimeric T cell receptor comprised of VEGF sequences linked to intracellular signaling sequences derived from the chain of the T cell receptor. After transduction of primary murine CD8 lymphocytes by such vectors, the transduced cells were shown to possess an efficient killing specificity for cells expressing the VEGF receptor, Flk-1, as measured by in vitro cytotoxicity assays. After adoptive transfer into tumor-bearing mice, the genetically modified cytotoxic T lymphocytes strongly inhibited the growth of a variety of syngeneic murine tumors and human tumor xenografts. An increased effect on in vivo tumor growth inhibition was seen when this therapy was combined with the systemic administration of TNP-470, a conventional angiogenesis inhibitor. The utilization of the immune system to target angiogenic markers expressed on tumor vasculature may prove to be a powerful means for controlling tumor growth.

Effects of real or simulated microgravity on plant cell growth and proliferation

NASA Astrophysics Data System (ADS)

Medina, Francisco Javier; Manzano, Ana Isabel; Herranz, Raul; Dijkstra, Camelia; Larkin, Oliver; Hill, Richard; Carnero-Díaz, Eugénie; van Loon, Jack J. W. A.; Anthony, Paul; Davey, Michael R.; Eaves, Laurence

Experiments on seed germination and seedling growth performed in real microgravity on the International Space Station and in different facilities for simulating microgravity in Earth-based laboratories (Random Positioning Machine and Magnetic Levitation), have provided evidence that the absence of gravity (or the artificial compensation of the gravity vector) results in the uncoupling of cell growth and proliferation in root meristematic cells. These are two essential cellular functions that support plant growth and development, which are strictly coordinated under normal ground gravity conditions. Under conditions of altered gravity, we observe that cell proliferation is enhanced, whereas cell growth is reduced, according to different morphometric, cytological and immunocytochemical parameters. Since coordination of cell growth and proliferation are major features of meristematic cells, this observed uncoupling represents a major stress condition for these cells, inducing major alterations in the pattern of plant development. Moreover, the expression of the cyclin B1 gene, a regulator of the entry into mitosis and normally used as an indicator of cell proliferation, appears reduced in the smaller and more actively proliferating cells of samples grown under the conditions of our experiments. These results are compatible with an alteration of the regulation of the cell cycle, producing a shorter G2 period. Interestingly, while cyclin B1 expression is depleted in these conditions in root meristematic cells, it is enhanced in cotyledons of the same seedlings, as shown by qPCR and by the expression of the gus reporter gene. It is known that regulation of root growth (including regulation of root meristematic activity) is driven mainly by auxin, whereas cytokinin is the key hormone regulating cotyledon growth. Therefore, our results indicate a major role of auxin in the sensitivity to altered gravity of root meristematic cells. Auxin is crucial in maintaining the coupling of cell growth and proliferation under normal conditions and it should have a decisive influence in the uncoupling of these processes under altered gravity. Experiments to detect auxin distribution in roots under altered gravity produced by diamagnetic levitation have shown that the lateral balanced distribution of the growth regulator in the root cap is altered slightly and that the total concentration of the auxin detected in root tips is somewhat reduced. These effects are independent of the orientation of statoliths in columella cells.

Enhancement of cell growth on honeycomb-structured polylactide surface using atmospheric-pressure plasma jet modification

NASA Astrophysics Data System (ADS)

Cheng, Kuang-Yao; Chang, Chia-Hsing; Yang, Yi-Wei; Liao, Guo-Chun; Liu, Chih-Tung; Wu, Jong-Shinn

2017-02-01

In this paper, we compare the cell growth results of NIH-3T3 and Neuro-2A cells over 72 h on flat and honeycomb structured PLA films without and with a two-step atmospheric-pressure nitrogen-based plasma jet treatment. We developed a fabrication system used for forming of a uniform honeycomb structure on PLA surface, which can produce two different pore sizes, 3-4 μm and 7-8 μm, of honeycomb pattern. We applied a previously developed nitrogen-based atmospheric-pressure dielectric barrier discharge (DBD) jet system to treat the PLA film without and with honeycomb structure. NIH-3T3 and a much smaller Neuro-2A cells were cultivated on the films under various surface conditions. The results show that the two-step plasma treatment in combination with a honeycomb structure can enhance cell growth on PLA film, should the cell size be not too smaller than the pore size of honeycomb structure, e.g., NIH-3T3. Otherwise, cell growth would be better on flat PLA film, e.g., Neuro-2A.

Fibroblast growth factor signaling is required for early somatic gonad development in zebrafish.

PubMed

Leerberg, Dena M; Sano, Kaori; Draper, Bruce W

2017-09-01

The vertebrate ovary and testis develop from a sexually indifferent gonad. During early development of the organism, primordial germ cells (the gamete lineage) and somatic gonad cells coalesce and begin to undergo growth and morphogenesis to form this bipotential gonad. Although this aspect of development is requisite for a fertile adult, little is known about the genetic regulation of early gonadogenesis in any vertebrate. Here, we provide evidence that fibroblast growth factor (Fgf) signaling is required for the early growth phase of a vertebrate bipotential gonad. Based on mutational analysis in zebrafish, we show that the Fgf ligand 24 (Fgf24) is required for proliferation, differentiation, and morphogenesis of the early somatic gonad, and as a result, most fgf24 mutants are sterile as adults. Additionally, we describe the ultrastructural elements of the early zebrafish gonad and show that distinct somatic cell populations can be identified soon after the gonad forms. Specifically, we show that fgf24 is expressed in an epithelial population of early somatic gonad cells that surrounds an inner population of mesenchymal somatic gonad cells that are in direct contact with the germ cells, and that fgf24 is required for stratification of the somatic tissue. Furthermore, based on gene expression analysis, we find that differentiation of the inner mesenchymal somatic gonad cells into functional cell types in the larval and early juvenile-stage gonad is dependent on Fgf24 signaling. Finally, we argue that the role of Fgf24 in zebrafish is functionally analogous to the role of tetrapod FGF9 in early gonad development.

Stem cells in Nanomia bijuga (Siphonophora), a colonial animal with localized growth zones.

PubMed

Siebert, Stefan; Goetz, Freya E; Church, Samuel H; Bhattacharyya, Pathikrit; Zapata, Felipe; Haddock, Steven H D; Dunn, Casey W

2015-01-01

Siphonophores (Hydrozoa) have unparalleled colony-level complexity, precision of colony organization, and functional specialization between zooids (i.e., the units that make up colonies). Previous work has shown that, unlike other colonial animals, most growth in siphonophores is restricted to one or two well-defined growth zones that are the sites of both elongation and zooid budding. It remained unknown, however, how this unique colony growth and development is realized at the cellular level. To understand the colony-level growth and development of siphonophores at the cellular level, we characterize the distribution of proliferating cells and interstitial stem cells (i-cells) in the siphonophore Nanomia bijuga. Within the colony, we find evidence that i-cells are present at the tip of the horn, the structure within the growth zone that gives rise to new zooids. Co-localized gene expression of vasa-1, pl10, piwi, nanos-1, and nanos-2 suggests that i-cells persist in the youngest zooid buds and that i-cells become progressively restricted to specific regions within the zooids until they are mostly absent from the oldest zooids. The examined genes remain expressed in gametogenic regions. No evidence for i-cells is found in the stem between maturing zooids. Domains of high cell proliferation include regions where the examined genes are expressed, but also include some areas in which the examined genes were not expressed such as the stem within the growth zones. Cell proliferation in regions devoid of vasa-1, pl10, piwi, nanos-1, and nanos-2 expression indicates the presence of mitotically active epithelial cell lineages and, potentially, progenitor cell populations. We provide the first evidence for i-cells in a siphonophore. Our findings suggest maintenance of i-cell populations at the sites of growth zones and that these sites are the main source of i-cells. This restriction of stem cells to particular regions in the colony, in combination with localized budding and spatial patterning during pro-bud subdivision, may play a major role in facilitating the precision of siphonophore growth. Spatially restricted maintenance of i-cells in mature zooids and absence of i-cells along the stem may explain the reduced developmental plasticity in older parts of the colony.

Clones of cells switch from reduction to enhancement of size variability in Arabidopsis sepals

PubMed Central

Tsugawa, Satoru; Hervieux, Nathan; Kierzkowski, Daniel; Routier-Kierzkowska, Anne-Lise; Sapala, Aleksandra; Hamant, Olivier; Smith, Richard S.; Boudaoud, Arezki

2017-01-01

Organs form with remarkably consistent sizes and shapes during development, whereas a high variability in growth is observed at the cell level. Given this contrast, it is unclear how such consistency in organ scale can emerge from cellular behavior. Here, we examine an intermediate scale, the growth of clones of cells in Arabidopsis sepals. Each clone consists of the progeny of a single progenitor cell. At early stages, we find that clones derived from a small progenitor cell grow faster than those derived from a large progenitor cell. This results in a reduction in clone size variability, a phenomenon we refer to as size uniformization. By contrast, at later stages of clone growth, clones change their growth pattern to enhance size variability, when clones derived from larger progenitor cells grow faster than those derived from smaller progenitor cells. Finally, we find that, at early stages, fast growing clones exhibit greater cell growth heterogeneity. Thus, cellular variability in growth might contribute to a decrease in the variability of clones throughout the sepal. PMID:29183944

Hypoxia-activated prodrug TH-302 decreased survival rate of canine lymphoma cells under hypoxic condition.

PubMed

Yamazaki, Hiroki; Lai, Yu-Chang; Tateno, Morihiro; Setoguchi, Asuka; Goto-Koshino, Yuko; Endo, Yasuyuki; Nakaichi, Munekazu; Tsujimoto, Hajime; Miura, Naoki

2017-01-01

We tested the hypotheses that hypoxic stimulation enhances growth potentials of canine lymphoma cells by activating hypoxia-inducible factor 1α (HIF-1α), and that the hypoxia-activated prodrug (TH-302) inhibits growth potentials in the cells. We investigated how hypoxic culture affects the growth rate, chemoresistance, and invasiveness of canine lymphoma cells and doxorubicin (DOX)-resistant lymphoma cells, and influences of TH-302 on survival rate of the cells under hypoxic conditions. Our results demonstrated that hypoxic culture upregulated the expression of HIF-1α and its target genes, including ATP-binding cassette transporter B1 (ABCB1), ATP-binding cassette transporter G2 (ABCG2), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and survivin, and enhanced the growth rate, DOX resistance, and invasiveness of the cells. Additionally, TH-302 decreased the survival rate of the cells under hypoxic condition. Our studies suggest that hypoxic stimulation may advance the tumorigenicity of canine lymphoma cells, favoring malignant transformation. Therefore, the data presented may contribute to the development of TH-302-based hypoxia-targeting therapies for canine lymphoma.

Signaling molecules involved in the transition of growth to development of Dictyostelium discoideum.

PubMed

Mir, Hina A; Rajawat, Jyotika; Pradhan, Shalmali; Begum, Rasheedunnisa

2007-03-01

The social amoeba Dictyostelium discoideum, a powerful paradigm provides clear insights into the regulation of growth and development. In addition to possessing complex individual cellular functions like a unicellular eukaryote, D. discoideum cells face the challenge of multicellular development. D. discoideum undergoes a relatively simple differentiation process mainly by cAMP mediated pathway. Despite this relative simplicity, the regulatory signaling pathways are as complex as those seen in metazoan development. However, the introduction of restriction-enzyme-mediated integration (REMI) technique to produce developmental gene knockouts has provided novel insights into the discovery of signaling molecules and their role in D. discoideum development. Cell cycle phase is an important aspect for differentiation of D. discoideum, as cells must reach a specific stage to enter into developmental phase and specific cell cycle regulators are involved in arresting growth phase genes and inducing the developmental genes. In this review, we present an overview of the signaling molecules involved in the regulation of growth to differentiation transition (GDT), molecular mechanism of early developmental events leading to generation of cAMP signal and components of cAMP relay system that operate in this paradigm.

The chromaffin cell: paradigm in cell, developmental and growth factor biology.

PubMed Central

Unsicker, K

1993-01-01

This article reviews the chromaffin cell in relation to studies that have elucidated fundamental phenomena in cell biology (the molecular anatomy of exocytosis) and developmental neuroscience (the principle of neuropoiesis in the development of the sympathoadrenal cell lineage). A final section addresses growth factor synthesis and storage in chromaffin cells and their implications for the treatment of neurological disorders, such as Parkinson's disease. Images Fig. 3 PMID:8300412

Development of hyper osmotic resistant CHO host cells for enhanced antibody production.

PubMed

Kamachi, Yasuharu; Omasa, Takeshi

2018-04-01

Cell culture platform processes are generally employed to shorten the duration of new product development. A fed-batch process with continuous feeding is a conventional platform process for monoclonal antibody production using Chinese hamster ovary (CHO) cells. To establish a simplified platform process, the feeding method can be changed from continuous feed to bolus feed. However, this change induces a rapid increase of osmolality by the bolus addition of nutrients. The increased osmolality suppresses cell culture growth, and the final product concentration is decreased. In this study, osmotic resistant CHO host cells were developed to attain a high product concentration. To establish hyper osmotic resistant CHO host cells, CHO-S host cells were passaged long-term in a hyper osmotic basal medium. There were marked differences in cell growth of the original and established host cells under iso- (328 mOsm/kg) or hyper-osmolality (over 450 mOsm/kg) conditions. Cell growth of the original CHO host cells was markedly decreased by the induction of osmotic stress, whereas cell growth of the hyper osmotic resistant CHO host cells was not affected. The maximum viable cell concentration of hyper osmotic resistant CHO host cells was 132% of CHO-S host cells after the induction of osmotic stress. Moreover, the hyper osmotic resistant characteristic of established CHO host cells was maintained even after seven passages in iso-osmolality basal medium. The use of hyper osmotic resistance CHO host cells to create a monoclonal antibody production cell line might be a new approach to increase final antibody concentrations with a fed-batch process. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Optimization and critical evaluation of decellularization strategies to develop renal extracellular matrix scaffolds as biological templates for organ engineering and transplantation.

PubMed

Caralt, M; Uzarski, J S; Iacob, S; Obergfell, K P; Berg, N; Bijonowski, B M; Kiefer, K M; Ward, H H; Wandinger-Ness, A; Miller, W M; Zhang, Z J; Abecassis, M M; Wertheim, J A

2015-01-01

The ability to generate patient-specific cells through induced pluripotent stem cell (iPSC) technology has encouraged development of three-dimensional extracellular matrix (ECM) scaffolds as bioactive substrates for cell differentiation with the long-range goal of bioengineering organs for transplantation. Perfusion decellularization uses the vasculature to remove resident cells, leaving an intact ECM template wherein new cells grow; however, a rigorous evaluative framework assessing ECM structural and biochemical quality is lacking. To address this, we developed histologic scoring systems to quantify fundamental characteristics of decellularized rodent kidneys: ECM structure (tubules, vessels, glomeruli) and cell removal. We also assessed growth factor retention--indicating matrix biofunctionality. These scoring systems evaluated three strategies developed to decellularize kidneys (1% Triton X-100, 1% Triton X-100/0.1% sodium dodecyl sulfate (SDS) and 0.02% Trypsin-0.05% EGTA/1% Triton X-100). Triton and Triton/SDS preserved renal microarchitecture and retained matrix-bound basic fibroblast growth factor and vascular endothelial growth factor. Trypsin caused structural deterioration and growth factor loss. Triton/SDS-decellularized scaffolds maintained 3 h of leak-free blood flow in a rodent transplantation model and supported repopulation with human iPSC-derived endothelial cells and tubular epithelial cells ex vivo. Taken together, we identify an optimal Triton/SDS-based decellularization strategy that produces a biomatrix that may ultimately serve as a rodent model for kidney bioengineering. © Copyright 2014 The American Society of Transplantation and the American Society of Transplant Surgeons.

The Control of Growth Symmetry Breaking in the Arabidopsis Hypocotyl.

PubMed

Peaucelle, Alexis; Wightman, Raymond; Höfte, Herman

2015-06-29

Complex shapes in biology depend on the ability of cells to shift from isotropic to anisotropic growth during development. In plants, this growth symmetry breaking reflects changes in the extensibility of the cell walls. The textbook view is that the direction of turgor-driven cell expansion depends on the cortical microtubule (CMT)-mediated orientation of cellulose microfibrils. Here, we show that this view is incomplete at best. We used atomic force microscopy (AFM) to study changes in cell-wall mechanics associated with growth symmetry breaking within the hypocotyl epidermis. We show that, first, growth symmetry breaking is preceded by an asymmetric loosening of longitudinal, as compared to transverse, anticlinal walls, in the absence of a change in CMT orientation. Second, this wall loosening is triggered by the selective de-methylesterification of cell-wall pectin in longitudinal walls, and, third, the resultant mechanical asymmetry is required for the growth symmetry breaking. Indeed, preventing or promoting pectin de-methylesterification, respectively, increased or decreased the stiffness of all the cell walls, but in both cases reduced the growth anisotropy. Finally, we show that the subsequent CMT reorientation contributes to the consolidation of the growth axis but is not required for the growth symmetry breaking. We conclude that growth symmetry breaking is controlled at a cellular scale by bipolar pectin de-methylesterification, rather than by the cellulose-dependent mechanical anisotropy of the cell walls themselves. Such a cell asymmetry-driven mechanism is comparable to that underlying tip growth in plants but also anisotropic cell growth in animal cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Forkhead Transcription Factor FOXP2 Is Required for Regulation of p21WAF1/CIP1 in 143B Osteosarcoma Cell Growth Arrest.

PubMed

Gascoyne, Duncan M; Spearman, Hayley; Lyne, Linden; Puliyadi, Rathi; Perez-Alcantara, Marta; Coulton, Les; Fisher, Simon E; Croucher, Peter I; Banham, Alison H

2015-01-01

Mutations of the forkhead transcription factor FOXP2 gene have been implicated in inherited speech-and-language disorders, and specific Foxp2 expression patterns in neuronal populations and neuronal phenotypes arising from Foxp2 disruption have been described. However, molecular functions of FOXP2 are not completely understood. Here we report a requirement for FOXP2 in growth arrest of the osteosarcoma cell line 143B. We observed endogenous expression of this transcription factor both transiently in normally developing murine osteoblasts and constitutively in human SAOS-2 osteosarcoma cells blocked in early osteoblast development. Critically, we demonstrate that in 143B osteosarcoma cells with minimal endogenous expression, FOXP2 induced by growth arrest is required for up-regulation of p21WAF1/CIP1. Upon growth factor withdrawal, FOXP2 induction occurs rapidly and precedes p21WAF1/CIP1 activation. Additionally, FOXP2 expression could be induced by MAPK pathway inhibition in growth-arrested 143B cells, but not in traditional cell line models of osteoblast differentiation (MG-63, C2C12, MC3T3-E1). Our data are consistent with a model in which transient upregulation of Foxp2 in pre-osteoblast mesenchymal cells regulates a p21-dependent growth arrest checkpoint, which may have implications for normal mesenchymal and osteosarcoma biology.

The Forkhead Transcription Factor FOXP2 Is Required for Regulation of p21WAF1/CIP1 in 143B Osteosarcoma Cell Growth Arrest

PubMed Central

Gascoyne, Duncan M.; Spearman, Hayley; Lyne, Linden; Puliyadi, Rathi; Perez-Alcantara, Marta; Coulton, Les; Fisher, Simon E.; Croucher, Peter I.; Banham, Alison H.

2015-01-01

Mutations of the forkhead transcription factor FOXP2 gene have been implicated in inherited speech-and-language disorders, and specific Foxp2 expression patterns in neuronal populations and neuronal phenotypes arising from Foxp2 disruption have been described. However, molecular functions of FOXP2 are not completely understood. Here we report a requirement for FOXP2 in growth arrest of the osteosarcoma cell line 143B. We observed endogenous expression of this transcription factor both transiently in normally developing murine osteoblasts and constitutively in human SAOS-2 osteosarcoma cells blocked in early osteoblast development. Critically, we demonstrate that in 143B osteosarcoma cells with minimal endogenous expression, FOXP2 induced by growth arrest is required for up-regulation of p21WAF1/CIP1. Upon growth factor withdrawal, FOXP2 induction occurs rapidly and precedes p21WAF1/CIP1 activation. Additionally, FOXP2 expression could be induced by MAPK pathway inhibition in growth-arrested 143B cells, but not in traditional cell line models of osteoblast differentiation (MG-63, C2C12, MC3T3-E1). Our data are consistent with a model in which transient upregulation of Foxp2 in pre-osteoblast mesenchymal cells regulates a p21-dependent growth arrest checkpoint, which may have implications for normal mesenchymal and osteosarcoma biology. PMID:26034982

Gene therapy with growth factors for periodontal tissue engineering–A review

PubMed Central

Gupta, Shipra; Mahendra, Aneet

2012-01-01

The treatment of oral and periodontal diseases and associated anomalies accounts for a significant proportion of the healthcare burden, with the manifestations of these conditions being functionally and psychologically debilitating. A challenge faced by periodontal therapy is the predictable regeneration of periodontal tissues lost as a consequence of disease. Growth factors are critical to the development, maturation, maintenance and repair of oral tissues as they establish an extra-cellular environment that is conducive to cell and tissue growth. Tissue engineering principles aim to exploit these properties in the development of biomimetic materials that can provide an appropriate microenvironment for tissue development. The aim of this paper is to review emerging periodontal therapies in the areas of materials science, growth factor biology and cell/gene therapy. Various such materials have been formulated into devices that can be used as vehicles for delivery of cells, growth factors and DNA. Different mechanisms of drug delivery are addressed in the context of novel approaches to reconstruct and engineer oral and tooth supporting structure. Key words: Periodontal disease, gene therapy, regeneration, tissue repair, growth factors, tissue engineering. PMID:22143705

Neural Stem Cell Differentiation Using Microfluidic Device-Generated Growth Factor Gradient.

PubMed

Kim, Ji Hyeon; Sim, Jiyeon; Kim, Hyun-Jung

2018-04-11

Neural stem cells (NSCs) have the ability to self-renew and differentiate into multiple nervous system cell types. During embryonic development, the concentrations of soluble biological molecules have a critical role in controlling cell proliferation, migration, differentiation and apoptosis. In an effort to find optimal culture conditions for the generation of desired cell types in vitro , we used a microfluidic chip-generated growth factor gradient system. In the current study, NSCs in the microfluidic device remained healthy during the entire period of cell culture, and proliferated and differentiated in response to the concentration gradient of growth factors (epithermal growth factor and basic fibroblast growth factor). We also showed that overexpression of ASCL1 in NSCs increased neuronal differentiation depending on the concentration gradient of growth factors generated in the microfluidic gradient chip. The microfluidic system allowed us to study concentration-dependent effects of growth factors within a single device, while a traditional system requires multiple independent cultures using fixed growth factor concentrations. Our study suggests that the microfluidic gradient-generating chip is a powerful tool for determining the optimal culture conditions.

Sequential growth factor application in bone marrow stromal cell ligament engineering.

PubMed

Moreau, Jodie E; Chen, Jingsong; Horan, Rebecca L; Kaplan, David L; Altman, Gregory H

2005-01-01

In vitro bone marrow stromal cell (BMSC) growth may be enhanced through culture medium supplementation, mimicking the biochemical environment in which cells optimally proliferate and differentiate. We hypothesize that the sequential administration of growth factors to first proliferate and then differentiate BMSCs cultured on silk fiber matrices will support the enhanced development of ligament tissue in vitro. Confluent second passage (P2) BMSCs obtained from purified bone marrow aspirates were seeded on RGD-modified silk matrices. Seeded matrices were divided into three groups for 5 days of static culture, with medium supplement of basic fibroblast growth factor (B) (1 ng/mL), epidermal growth factor (E; 1 ng/mL), or growth factor-free control (C). After day 5, medium supplementation was changed to transforming growth factor-beta1 (T; 5 ng/mL) or C for an additional 9 days of culture. Real-time RT-PCR, SEM, MTT, histology, and ELISA for collagen type I of all sample groups were performed. Results indicated that BT supported the greatest cell ingrowth after 14 days of culture in addition to the greatest cumulative collagen type I expression measured by ELISA. Sequential growth factor application promoted significant increases in collagen type I transcript expression from day 5 of culture to day 14, for five of six groups tested. All T-supplemented samples surpassed their respective control samples in both cell ingrowth and collagen deposition. All samples supported spindle-shaped, fibroblast cell morphology, aligning with the direction of silk fibers. These findings indicate significant in vitro ligament development after only 14 days of culture when using a sequential growth factor approach.

Connective tissue growth factor is expressed in bone marrow stromal cells and promotes interleukin-7-dependent B lymphopoiesis.

PubMed

Cheung, Laurence C; Strickland, Deborah H; Howlett, Meegan; Ford, Jette; Charles, Adrian K; Lyons, Karen M; Brigstock, David R; Goldschmeding, Roel; Cole, Catherine H; Alexander, Warren S; Kees, Ursula R

2014-07-01

Hematopoiesis occurs in a complex bone marrow microenvironment in which bone marrow stromal cells provide critical support to the process through direct cell contact and indirectly through the secretion of cytokines and growth factors. We report that connective tissue growth factor (Ctgf, also known as Ccn2) is highly expressed in murine bone marrow stromal cells. In contrast, connective tissue growth factor is barely detectable in unfractionated adult bone marrow cells. While connective tissue growth factor has been implicated in hematopoietic malignancies, and is known to play critical roles in skeletogenesis and regulation of bone marrow stromal cells, its role in hematopoiesis has not been described. Here we demonstrate that the absence of connective tissue growth factor in mice results in impaired hematopoiesis. Using a chimeric fetal liver transplantation model, we show that absence of connective tissue growth factor has an impact on B-cell development, in particular from pro-B to more mature stages, which is linked to a requirement for connective tissue growth factor in bone marrow stromal cells. Using in vitro culture systems, we demonstrate that connective tissue growth factor potentiates B-cell proliferation and promotes pro-B to pre-B differentiation in the presence of interleukin-7. This study provides a better understanding of the functions of connective tissue growth factor within the bone marrow, showing the dual regulatory role of the growth factor in skeletogenesis and in stage-specific B lymphopoiesis. Copyright© Ferrata Storti Foundation.

Connective tissue growth factor is expressed in bone marrow stromal cells and promotes interleukin-7-dependent B lymphopoiesis

PubMed Central

Cheung, Laurence C.; Strickland, Deborah H.; Howlett, Meegan; Ford, Jette; Charles, Adrian K.; Lyons, Karen M.; Brigstock, David R.; Goldschmeding, Roel; Cole, Catherine H.; Alexander, Warren S.; Kees, Ursula R.

2014-01-01

Hematopoiesis occurs in a complex bone marrow microenvironment in which bone marrow stromal cells provide critical support to the process through direct cell contact and indirectly through the secretion of cytokines and growth factors. We report that connective tissue growth factor (Ctgf, also known as Ccn2) is highly expressed in murine bone marrow stromal cells. In contrast, connective tissue growth factor is barely detectable in unfractionated adult bone marrow cells. While connective tissue growth factor has been implicated in hematopoietic malignancies, and is known to play critical roles in skeletogenesis and regulation of bone marrow stromal cells, its role in hematopoiesis has not been described. Here we demonstrate that the absence of connective tissue growth factor in mice results in impaired hematopoiesis. Using a chimeric fetal liver transplantation model, we show that absence of connective tissue growth factor has an impact on B-cell development, in particular from pro-B to more mature stages, which is linked to a requirement for connective tissue growth factor in bone marrow stromal cells. Using in vitro culture systems, we demonstrate that connective tissue growth factor potentiates B-cell proliferation and promotes pro-B to pre-B differentiation in the presence of interleukin-7. This study provides a better understanding of the functions of connective tissue growth factor within the bone marrow, showing the dual regulatory role of the growth factor in skeletogenesis and in stage-specific B lymphopoiesis. PMID:24727816

Effect of the association of IGF-I, IGF-II, bFGF, TGF-beta1, GM-CSF, and LIF on the development of bovine embryos produced in vitro.

PubMed

Neira, J A; Tainturier, D; Peña, M A; Martal, J

2010-03-15

This study examined the influence of the following growth factors and cytokines on early embryonic development: insulin-like growth factors I and II (IGF-I, IGF-II), basic fibroblast growth factor (bFGF), transforming growth factor (TGF-beta), granulocyte-macrophage colony-stimulating factor (GM-CSF), and leukemia inhibitory factor (LIF). Synthetic oviduct fluid (SOF) was used as the culture medium. We studied the development of bovine embryos produced in vitro and cultured until Day 9 after fertilization. TGF-beta1, bFGF, GM-CSF, and LIF used on their own significantly improved the yield of hatched blastocysts. IGF-I, bFGF, TGF-beta1, GM-CSF, and LIF significantly accelerated embryonic development, especially the change from the expanded blastocyst to hatched blastocyst stages. Use of a combination of these growth factors and cytokines (GF-CYK) in SOF medium produced higher percentages of blastocysts and hatched blastocysts than did use of SOF alone (45% and 22% vs. 24% and 12%; P<0.05) on Day 8 after in vitro fertilization and similar results to use of SOF+10% fetal calf serum (38% and 16%, at the same stages, respectively). The averages of total cells, inner cell mass cells, and trophectoderm cells of exclusively in vitro Day-8 blastocysts for pooled GF-CYK treatments were higher than those for SOF and similar to those for fetal calf serum. The presence of these growth factors and cytokines in the embryo culture medium therefore has a combined stimulatory action on embryonic development; in particular through an increase in hatching rate and in the number of cells of both the inner cell mass and trophoblast. These results are the first to demonstrate that use of a combination of recombinant growth factors and cytokine, as IGF-I, IGF-II, bFGF, TGF-beta1, LIF, and GM-CSF, produces similar results to 10% fetal calf serum for the development of in vitro-produced bovine embryos. This entirely synthetic method of embryo culture has undeniable advantages for the biosecurity of embryo transfer. Copyright 2010 Elsevier Inc. All rights reserved.

Interaction of tumor and host cells with adhesion and extracellular matrix molecules in the development of multiple myeloma.

PubMed

Teoh, G; Anderson, K C

1997-02-01

Adhesion molecules play an important role in the growth regulation and migration of multiple myeloma (MM) cells. They mediate homing of MM cells to the bone marrow and MM cell to bone marrow stromal cell adhesion, with resultant interleukin-6 related autocrine and paracine growth and antiapoptotic affects. Their pattern of expression on tumor cells correlates with the development of plasma cell leukemia or extramedullary disease. Clinically, expression of adhesion molecules on tumor cells or in the serum has already shown prognostic utility. Finally, since adhesion molecules are involved at multiple steps in the pathogenesis of MM, therapeutic studies may target these molecules.

Drosophila Growth and Development in the Absence of dMyc and dMnt

PubMed Central

Pierce, Sarah B.; Yost, Cynthia; Anderson, Sarah A. R.; Flynn, Erin M.; Delrow, Jeffrey; Eisenman, Robert N.

2008-01-01

Myc oncoproteins are essential regulators of the growth and proliferation of mammalian cells. In Drosophila the single ortholog of Myc (dMyc), encoded by the dm gene, influences organismal size and the growth of both mitotic and endoreplicating cells. A null mutation in dm results in attenuated endoreplication and growth arrest early in larval development. Drosophila also contains a single ortholog of the mammalian Mad/Mnt transcriptional repressor proteins (dMnt), which is thought to antagonize dMyc function. Here we show that animals lacking both dMyc and dMnt display increased viability and grow significantly larger and develop further than dMyc single mutants. We observe increased endoreplication and growth of larval tissues in these double mutants and disproportionate growth of the imaginal discs. Gene expression analysis indicates that loss of dMyc leads to decreased expression of genes required for ribosome biogenesis and protein synthesis. The additional loss of dMnt partially rescues expression of a small number of dMyc and dMnt genes that are primarily involved in rRNA synthesis and processing. Our results indicate that dMnt repression is normally overridden by dMyc activation during larval development. Therefore the severity of the dm null phenotype is likely due to unopposed repression by dMnt on a subset of genes critical for cell and organismal growth. Surprisingly, considerable growth and development can occur in the absence of both dMyc and dMnt. PMID:18241851

Cell-autonomous intracellular androgen receptor signaling drives the growth of human prostate cancer initiating cells.

PubMed

Vander Griend, Donald J; D'Antonio, Jason; Gurel, Bora; Antony, Lizamma; Demarzo, Angelo M; Isaacs, John T

2010-01-01

The lethality of prostate cancer is due to the continuous growth of cancer initiating cells (CICs) which are often stimulated by androgen receptor (AR) signaling. However, the underlying molecular mechanism(s) for such AR-mediated growth stimulation are not fully understood. Such mechanisms may involve cancer cell-dependent induction of tumor stromal cells to produce paracrine growth factors or could involve cancer cell autonomous autocrine and/or intracellular AR signaling pathways. We utilized clinical samples, animal models and a series of AR-positive human prostate cancer cell lines to evaluate AR-mediated growth stimulation of prostate CICs. The present studies document that stromal AR expression is not required for prostate cancer growth, since tumor stroma surrounding AR-positive human prostate cancer metastases (N = 127) are characteristically AR-negative. This lack of a requirement for AR expression in tumor stromal cells is also documented by the fact that human AR-positive prostate cancer cells grow equally well when xenografted in wild-type versus AR-null nude mice. AR-dependent growth stimulation was documented to involve secretion, extracellular binding, and signaling by autocrine growth factors. Orthotopic xenograft animal studies documented that the cellautonomous autocrine growth factors which stimulate prostate CIC growth are not the andromedins secreted by normal prostate stromal cells. Such cell autonomous and extracellular autocrine signaling is necessary but not sufficient for the optimal growth of prostate CICs based upon the response to anti-androgen plus/or minus preconditioned media. AR-induced growth stimulation of human prostate CICs requires AR-dependent intracellular pathways. The identification of such AR-dependent intracellular pathways offers new leads for the development of effective therapies for prostate cancer. (c) 2009 Wiley-Liss, Inc.

Culture of preimplantation mouse embryos affects fetal development and the expression of imprinted genes.

PubMed

Khosla, S; Dean, W; Brown, D; Reik, W; Feil, R

2001-03-01

Culture of preimplantation mammalian embryos and cells can influence their subsequent growth and differentiation. Previously, we reported that culture of mouse embryonic stem cells is associated with deregulation of genomic imprinting and affects the potential for these cells to develop into normal fetuses. The purpose of our current study was to determine whether culture of preimplantation mouse embryos in a chemically defined medium (M16) with or without fetal calf serum (FCS) can affect their subsequent development and imprinted gene expression. Only one third of the blastocysts that had been cultured from two-cell embryos in M16 medium complemented with FCS developed into viable Day 14 fetuses after transfer into recipients. These M16 + FCS fetuses were reduced in weight as compared with controls and M16 fetuses and had decreased expression of the imprinted H19 and insulin-like growth factor 2 genes associated with a gain of DNA methylation at an imprinting control region upstream of H19. They also displayed increased expression of the imprinted gene Grb10. The growth factor receptor binding gene Grb7, in contrast, was strongly reduced in its expression in most of the M16 + FCS fetuses. No alterations were detected for the imprinted gene MEST: Preimplantation culture in the presence of serum can influence the regulation of multiple growth-related imprinted genes, thus leading to aberrant fetal growth and development.

Development of processes for the production of low cost silicon dendritic web for solar cells

NASA Technical Reports Server (NTRS)

Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Hopkins, R. H.; Skutch, M. E.; Driggers, J. M.; Hill, F. E.

1980-01-01

High area output rates and continuous, automated growth are two key technical requirements for the growth of low-cost silicon ribbons for solar cells. By means of computer-aided furnace design, silicon dendritic web output rates as high as 27 sq cm/min have been achieved, a value in excess of that projected to meet a $0.50 per peak watt solar array manufacturing cost. The feasibility of simultaneous web growth while the melt is replenished with pelletized silicon has also been demonstrated. This step is an important precursor to the development of an automated growth system. Solar cells made on the replenished material were just as efficient as devices fabricated on typical webs grown without replenishment. Moreover, web cells made on a less-refined, pelletized polycrystalline silicon synthesized by the Battelle process yielded efficiencies up to 13% (AM1).

Development of an in silico stochastic 4D model of tumor growth with angiogenesis.

PubMed

Forster, Jake C; Douglass, Michael J J; Harriss-Phillips, Wendy M; Bezak, Eva

2017-04-01

A stochastic computer model of tumour growth with spatial and temporal components that includes tumour angiogenesis was developed. In the current work it was used to simulate head and neck tumour growth. The model also provides the foundation for a 4D cellular radiotherapy simulation tool. The model, developed in Matlab, contains cell positions randomised in 3D space without overlap. Blood vessels are represented by strings of blood vessel units which branch outwards to achieve the desired tumour relative vascular volume. Hypoxic cells have an increased cell cycle time and become quiescent at oxygen tensions less than 1 mmHg. Necrotic cells are resorbed. A hierarchy of stem cells, transit cells and differentiated cells is considered along with differentiated cell loss. Model parameters include the relative vascular volume (2-10%), blood oxygenation (20-100 mmHg), distance from vessels to the onset of necrosis (80-300 μm) and probability for stem cells to undergo symmetric division (2%). Simulations were performed to observe the effects of hypoxia on tumour growth rate for head and neck cancers. Simulations were run on a supercomputer with eligible parts running in parallel on 12 cores. Using biologically plausible model parameters for head and neck cancers, the tumour volume doubling time varied from 45 ± 5 days (n = 3) for well oxygenated tumours to 87 ± 5 days (n = 3) for severely hypoxic tumours. The main achievements of the current model were randomised cell positions and the connected vasculature structure between the cells. These developments will also be beneficial when irradiating the simulated tumours using Monte Carlo track structure methods. © 2017 American Association of Physicists in Medicine.

SRF selectively controls tip cell invasive behavior in angiogenesis.

PubMed

Franco, Claudio A; Blanc, Jocelyne; Parlakian, Ara; Blanco, Raquel; Aspalter, Irene M; Kazakova, Natalia; Diguet, Nicolas; Mylonas, Elena; Gao-Li, Jacqueline; Vaahtokari, Anne; Penard-Lacronique, Virgine; Fruttiger, Markus; Rosewell, Ian; Mericskay, Mathias; Gerhardt, Holger; Li, Zhenlin

2013-06-01

Efficient angiogenic sprouting is essential for embryonic, postnatal and tumor development. Serum response factor (SRF) is known to be important for embryonic vascular development. Here, we studied the effect of inducible endothelial-specific deletion of Srf in postnatal and adult mice. We find that endothelial SRF activity is vital for postnatal growth and survival, and is equally required for developmental and pathological angiogenesis, including during tumor growth. Our results demonstrate that SRF is selectively required for endothelial filopodia formation and cell contractility during sprouting angiogenesis, but seems dispensable for vascular remodeling. At the molecular level, we observe that vascular endothelial growth factor A induces nuclear accumulation of myocardin-related transcription factors (MRTFs) and regulates MRTF/SRF-dependent target genes including Myl9, which is important for endothelial cell migration in vitro. We conclude that SRF has a unique function in regulating migratory tip cell behavior during sprouting angiogenesis. We hypothesize that targeting the SRF pathway could provide an opportunity to selectively target tip cell filopodia-driven angiogenesis to restrict tumor growth.

Determinate Root Growth and Meristem Maintenance in Angiosperms

PubMed Central

Shishkova, S.; Rost, T. L.; Dubrovsky, J. G.

2008-01-01

Background The difference between indeterminate and determinate growth in plants consists of the presence or absence of an active meristem in the fully developed organ. Determinate root growth implies that the root apical meristem (RAM) becomes exhausted. As a consequence, all cells in the root tip differentiate. This type of growth is widely found in roots of many angiosperm taxa and might have evolved as a developmental adaptation to water deficit (in desert Cactaceae), or low mineral content in the soil (proteoid roots in various taxa). Scope and Conclusions This review considers the mechanisms of determinate root growth to better understand how the RAM is maintained, how it functions, and the cellular and genetic bases of these processes. The role of the quiescent centre in RAM maintenance and exhaustion will be analysed. During root ageing, the RAM becomes smaller and its organization changes; however, it remains unknown whether every root is truly determinate in the sense that its RAM becomes exhausted before senescence. We define two types of determinate growth: constitutive where determinacy is a natural part of root development; and non-constitutive where determinacy is induced usually by an environmental factor. Determinate root growth is proposed to include two phases: the indeterminate growth phase, when the RAM continuously produces new cells; and the termination growth phase, when cell production gradually decreases and eventually ceases. Finally, new concepts regarding stem cells and a stem cell niche are discussed to help comprehend how the meristem is maintained in a broad taxonomic context. PMID:17954472

Growth of Myxococcus xanthus in continuous-flow-cell bioreactors as a method for studying development.

PubMed

Smaldone, Gregory T; Jin, Yujie; Whitfield, Damion L; Mu, Andrew Y; Wong, Edward C; Wuertz, Stefan; Singer, Mitchell

2014-04-01

Nutrient sensors and developmental timers are two classes of genes vital to the establishment of early development in the social soil bacterium Myxococcus xanthus. The products of these genes trigger and regulate the earliest events that drive the colony from a vegetative state to aggregates, which ultimately leads to the formation of fruiting bodies and the cellular differentiation of the individual cells. In order to more accurately identify the genes and pathways involved in the initiation of this multicellular developmental program in M. xanthus, we adapted a method of growing vegetative populations within a constant controllable environment by using flow cell bioreactors, or flow cells. By establishing an M. xanthus community within a flow cell, we are able to test developmental responses to changes in the environment with fewer concerns for effects due to nutrient depletion or bacterial waste production. This approach allows for greater sensitivity in investigating communal environmental responses, such as nutrient sensing. To demonstrate the versatility of our growth environment, we carried out time-lapse confocal laser scanning microscopy to visualize M. xanthus biofilm growth and fruiting body development, as well as fluorescence staining of exopolysaccharides deposited by biofilms. We also employed the flow cells in a nutrient titration to determine the minimum concentration required to sustain vegetative growth. Our data show that by using a flow cell, M. xanthus can be held in a vegetative growth state at low nutrient concentrations for long periods, and then, by slightly decreasing the nutrient concentration, cells can be allowed to initiate the developmental program.

Gravitropic moss cells default to spiral growth on the clinostat and in microgravity during spaceflight

NASA Technical Reports Server (NTRS)

Kern, Volker D.; Schwuchow, Jochen M.; Reed, David W.; Nadeau, Jeanette A.; Lucas, Jessica; Skripnikov, Alexander; Sack, Fred D.

2005-01-01

In addition to shoots and roots, the gravity (g)-vector orients the growth of specialized cells such as the apical cell of dark-grown moss protonemata. Each apical cell of the moss Ceratodon purpureus senses the g-vector and adjusts polar growth accordingly producing entire cultures of upright protonemata (negative gravitropism). The effect of withdrawing a constant gravity stimulus on moss growth was studied on two NASA Space Shuttle (STS) missions as well as during clinostat rotation on earth. Cultures grown in microgravity (spaceflight) on the STS-87 mission exhibited two successive phases of non-random growth and patterning, a radial outgrowth followed by the formation of net clockwise spiral growth. Also, cultures pre-aligned by unilateral light developed clockwise hooks during the subsequent dark period. The second spaceflight experiment flew on STS-107 which disintegrated during its descent on 1 February 2003. However, most of the moss experimental hardware was recovered on the ground, and most cultures, which had been chemically fixed during spaceflight, were retrieved. Almost all intact STS-107 cultures displayed strong spiral growth. Non-random culture growth including clockwise spiral growth was also observed after clinostat rotation. Together these data demonstrate the existence of default non-random growth patterns that develop at a population level in microgravity, a response that must normally be overridden and masked by a constant g-vector on earth.

Novel Insights into the Organization of Laticifer Cells: A Cell Comprising a Unified Whole System1

PubMed Central

Castelblanque, Lourdes; Balaguer, Begoña; Rodríguez, Juan José; Orozco, Marianela; Vera, Pablo

2016-01-01

Laticifer cells are specialized plant cells that synthesize and accumulate latex. Studies on laticifers have lagged behind in recent years, and data regarding the functional role of laticifers and their fitness benefit still remain elusive. Laticifer differentiation and its impact on plant growth and development also remain to be investigated. Here, cellular, molecular, and genetic tools were developed to examine the distribution, differentiation, ontogeny, and other characteristic features, as well as the potential developmental role of laticifer cells in the latex-bearing plant Euphorbia lathyris. The organization of the laticiferous system within the E. lathyris plant body is reported, emerging as a single elongated and branched coenocytic cell, constituting the largest cell type existing in plants. We also report the ontogeny and organization of laticifer cells in the embryo and the identification of a laticifer-associated gene expression pattern. Moreover, the identification of laticifer- and latex-deficient mutants (pil mutants) allowed for the identification of distinct loci regulating laticifer differentiation, growth, and metabolic activity. Additionally, pil mutants revealed that laticifer cells appear nonessential for plant growth and development, thus pointing toward their importance, instead, for specific ecophysiological adaptations of latex-bearing plants in natural environments. PMID:27468995

Systemic control of cell division and endoreduplication by NAA and BAP by modulating CDKs in root tip cells of Allium cepa.

PubMed

Tank, Jigna G; Thaker, Vrinda S

2014-01-01

Molecular mechanism regulated by auxin and cytokinin during endoreduplication, cell division, and elongation process is studied by using Allium cepa roots as a model system. The activity of CDK genes modulated by auxin and cytokinin during cell division, elongation, and endoreduplication process is explained in this research work. To study the significance of auxin and cytokinin in the management of cell division and endoreduplication process in plant meristematic cells at molecular level endoreduplication was developed in root tips of Allium cepa by giving colchicine treatment. There were inhibition of vegetative growth, formation of c-tumor at root tip, and development of endoreduplicated cells after colchicine treatment. This c-tumor was further treated with NAA and BAP to reinitiate vegetative growth in roots. BAP gave positive response in reinitiation of vegetative growth of roots from center of c-tumor. However, NAA gave negative response in reinitiation of vegetative growth of roots from c-tumor. Further, CDKs gene expression analysis from normal, endoreduplicated, and phytohormone (NAA or BAP) treated root tip was done and remarkable changes in transcription level of CDK genes in normal, endoreduplicated, and phytohormones treated cells were observed.

Systemic Control of Cell Division and Endoreduplication by NAA and BAP by Modulating CDKs in Root Tip Cells of Allium cepa

PubMed Central

Tank, Jigna G.; Thaker, Vrinda S.

2014-01-01

Molecular mechanism regulated by auxin and cytokinin during endoreduplication, cell division, and elongation process is studied by using Allium cepa roots as a model system. The activity of CDK genes modulated by auxin and cytokinin during cell division, elongation, and endoreduplication process is explained in this research work. To study the significance of auxin and cytokinin in the management of cell division and endoreduplication process in plant meristematic cells at molecular level endoreduplication was developed in root tips of Allium cepa by giving colchicine treatment. There were inhibition of vegetative growth, formation of c-tumor at root tip, and development of endoreduplicated cells after colchicine treatment. This c-tumor was further treated with NAA and BAP to reinitiate vegetative growth in roots. BAP gave positive response in reinitiation of vegetative growth of roots from center of c-tumor. However, NAA gave negative response in reinitiation of vegetative growth of roots from c-tumor. Further, CDKs gene expression analysis from normal, endoreduplicated, and phytohormone (NAA or BAP) treated root tip was done and remarkable changes in transcription level of CDK genes in normal, endoreduplicated, and phytohormones treated cells were observed. PMID:24955358

RNA Expression Profiling Reveals Differentially Regulated Growth Factor and Receptor Expression in Redirected Cancer Cells.

PubMed

Schmucker, Hannah S; Park, Jang Pyo; Coissieux, Marie-May; Bentires-Alj, Mohamed; Feltus, F Alex; Booth, Brian W

2017-05-01

Tumorigenic cells can be redirected to adopt a normal phenotype when transplanted into cleared mammary fat pads of juvenile female mice in specific ratios with normal epithelial cells. The redirected tumorigenic cells enter stem cell niches and provide progeny that differentiate into all mammary epithelial subtypes. We have developed an in vitro model that mimics the in vivo phenomenon. The shift in phenotype to redirection should be accomplished through a return to a normal gene expression state. To measure this shift, we interrogated the transcriptome of various in vitro model states in search for casual genes. For this study, expression of growth factors, cytokines, and their associated receptors was examined. In all, we queried 251 growth factor and cytokine-related genes. We found numerous growth factor and cytokine genes whose expression levels switched from expression levels seen in cancer cells to expression levels observed in normal cells. The comparisons of gene expression between normal mammary epithelial cells, tumor-derived cells, and redirected cancer cells have revealed insight into active and inactive growth factors and cytokines in cancer cell redirection.

Genetics Home Reference: osteoglophonic dysplasia

MedlinePlus

... as cell division, regulation of cell growth and maturation, formation of blood vessels, wound healing, and embryonic development. In particular, they play a major role in skeletal development. The FGFR1 protein spans the cell membrane, ...

A Stochastic Model of Eye Lens Growth

PubMed Central

Šikić, Hrvoje; Shi, Yanrong; Lubura, Snježana; Bassnett, Steven

2015-01-01

The size and shape of the ocular lens must be controlled with precision if light is to be focused sharply on the retina. The lifelong growth of the lens depends on the production of cells in the anterior epithelium. At the lens equator, epithelial cells differentiate into fiber cells, which are added to the surface of the existing fiber cell mass, increasing its volume and area. We developed a stochastic model relating the rates of cell proliferation and death in various regions of the lens epithelium to deposition of fiber cells and lens growth. Epithelial population dynamics were modeled as a branching process with emigration and immigration between various proliferative zones. Numerical simulations were in agreement with empirical measurements and demonstrated that, operating within the strict confines of lens geometry, a stochastic growth engine can produce the smooth and precise growth necessary for lens function. PMID:25816743

Jasmonate Controls Leaf Growth by Repressing Cell Proliferation and the Onset of Endoreduplication while Maintaining a Potential Stand-By Mode1[W][OA

PubMed Central

Noir, Sandra; Bömer, Moritz; Takahashi, Naoki; Ishida, Takashi; Tsui, Tjir-Li; Balbi, Virginia; Shanahan, Hugh; Sugimoto, Keiko; Devoto, Alessandra

2013-01-01

Phytohormones regulate plant growth from cell division to organ development. Jasmonates (JAs) are signaling molecules that have been implicated in stress-induced responses. However, they have also been shown to inhibit plant growth, but the mechanisms are not well understood. The effects of methyl jasmonate (MeJA) on leaf growth regulation were investigated in Arabidopsis (Arabidopsis thaliana) mutants altered in JA synthesis and perception, allene oxide synthase and coi1-16B (for coronatine insensitive1), respectively. We show that MeJA inhibits leaf growth through the JA receptor COI1 by reducing both cell number and size. Further investigations using flow cytometry analyses allowed us to evaluate ploidy levels and to monitor cell cycle progression in leaves and cotyledons of Arabidopsis and/or Nicotiana benthamiana at different stages of development. Additionally, a novel global transcription profiling analysis involving continuous treatment with MeJA was carried out to identify the molecular players whose expression is regulated during leaf development by this hormone and COI1. The results of these studies revealed that MeJA delays the switch from the mitotic cell cycle to the endoreduplication cycle, which accompanies cell expansion, in a COI1-dependent manner and inhibits the mitotic cycle itself, arresting cells in G1 phase prior to the S-phase transition. Significantly, we show that MeJA activates critical regulators of endoreduplication and affects the expression of key determinants of DNA replication. Our discoveries also suggest that MeJA may contribute to the maintenance of a cellular “stand-by mode” by keeping the expression of ribosomal genes at an elevated level. Finally, we propose a novel model for MeJA-regulated COI1-dependent leaf growth inhibition. PMID:23439917

Critical role of the axonal guidance cue EphrinB2 in lung growth, angiogenesis, and repair.

PubMed

Vadivel, Arul; van Haaften, Tim; Alphonse, Rajesh S; Rey-Parra, Gloria-Juliana; Ionescu, Lavinia; Haromy, Al; Eaton, Farah; Michelakis, Evangelos; Thébaud, Bernard

2012-03-01

Lung diseases characterized by alveolar damage currently lack efficient treatments. The mechanisms contributing to normal and impaired alveolar growth and repair are incompletely understood. Axonal guidance cues (AGC) are molecules that guide the outgrowth of axons to their targets. Among these AGCs, members of the Ephrin family also promote angiogenesis, cell migration, and organogenesis outside the nervous system. The role of Ephrins during alveolar growth and repair is unknown. We hypothesized that EphrinB2 promotes alveolar development and repair. We used in vitro and in vivo manipulation of EphrinB2 signaling to assess the role of this AGC during normal and impaired lung development. In vivo EphrinB2 knockdown using intranasal siRNA during the postnatal stage of alveolar development in rats arrested alveolar and vascular growth. In a model of O(2)-induced arrested alveolar growth in newborn rats, air space enlargement, loss of lung capillaries, and pulmonary hypertension were associated with decreased lung EphrinB2 and receptor EphB4 expression. In vitro, EphrinB2 preserved alveolar epithelial cell viability in O(2), decreased O(2)-induced alveolar epithelial cell apoptosis, and accelerated alveolar epithelial cell wound healing, maintained lung microvascular endothelial cell viability, and proliferation and vascular network formation. In vivo, treatment with intranasal EphrinB2 decreased alveolar epithelial and endothelial cell apoptosis, preserved alveolar and vascular growth in hyperoxic rats, and attenuated pulmonary hypertension. The AGC EphrinB2 may be a new therapeutic target for lung repair and pulmonary hypertension.

[Study of the growth and development of Chlorella on "Kosmos-1887"].

PubMed

Sychev, V N; Levinskikh, M A; Livanskaia, O G

1989-01-01

The growth, development and population characteristics of Chlorella cells flown for 13 days in space were investigated during their postflight cultivation. The growth rate of flown algae did not differ from that of ground-based controls in terms of increases in the cell number and biomass. All basic parameters of the specimens (generation time, number of developing autospores, time ratio of developmental phases) were ontogentically normal. Exposure of the algae to space flight as a component of the algobacterial cenosis--fish autotrophic-heterotrophic system produced no significant effect of the population or individual specimens during their postflight cultivation.

The cell-cycle interactome: a source of growth regulators?

PubMed

Blomme, Jonas; Inzé, Dirk; Gonzalez, Nathalie

2014-06-01

When plants develop, cell proliferation and cell expansion are tightly controlled in order to generate organs with a determinate final size such as leaves. Several studies have demonstrated the importance of the cell proliferation phase for leaf growth, illustrating that cell-cycle regulation is crucial for correct leaf development. A large and complex set of interacting proteins that constitute the cell-cycle interactome controls the transition from one cell-cycle phase to another. Here, we review the current knowledge on cell-cycle regulators from this interactome affecting final leaf size when their expression is altered, mainly in Arabidopsis. In addition to the description of mutants of CYCLIN-DEPENDENT KINASES (CDKs), CYCLINS (CYCs), and their transcriptional and post-translational regulators, a phenotypic analysis of gain- and loss-of-function mutants for 27 genes encoding proteins that interact with cell-cycle proteins is presented. This compilation of information shows that when cell-cycle-related genes are mis-expressed, leaf growth is often altered and that, seemingly, three main trends appear to be crucial in the regulation of final organ size by cell-cycle-related genes: (i) cellular compensation; (ii) gene dosage; and (iii) correct transition through the G2/M phase by ANAPHASE PROMOTING COMPLEX/CYCLOSOME (APC/C) activation. In conclusion, this meta-analysis shows that the cell-cycle interactome is enriched in leaf growth regulators, and illustrates the potential to identify new leaf growth regulators among putative new cell-cycle regulators. © The Author 2013. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

CP-31398 inhibits the growth of p53-mutated liver cancer cells in vitro and in vivo.

PubMed

He, Xing-Xing; Zhang, Yu-Nan; Yan, Jun-Wei; Yan, Jing-Jun; Wu, Qian; Song, Yu-Hu

2016-01-01

The tumor suppressor p53 is one of the most frequently mutated genes in hepatocellular carcinoma (HCC). Previous studies demonstrated that CP-31398 restored the native conformation of mutant p53 and trans-activated p53 downstream genes in tumor cells. However, the research on the application of CP-31398 to liver cancer has not been reported. Here, we investigated the effects of CP-31398 on the phenotype of HCC cells carrying p53 mutation. The effects of CP-31398 on the characteristic of p53-mutated HCC cells were evaluated through analyzing cell cycle, cell apoptosis, cell proliferation, and the expression of p53 downstream genes. In tumor xenografts developed by PLC/PRF/5 cells, the inhibition of tumor growth by CP-31398 was analyzed through gross morphology, growth curve, and the expression of p53-related genes. Firstly, we demonstrated that CP-31398 inhibited the growth of p53-mutated liver cancer cells in a dose-dependent and p53-dependent manner. Then, further study showed that CP-31398 re-activated wild-type p53 function in p53-mutated HCC cells, which resulted in inhibitive response of cell proliferation and an induction of cell-cycle arrest and apoptosis. Finally, in vivo data confirmed that CP-31398 blocked the growth of xenografts tumors through transactivation of p53-responsive downstream molecules. Our results demonstrated that CP-31398 induced desired phenotypic change of p53-mutated HCC cells in vitro and in vivo, which revealed that CP-31398 would be developed as a therapeutic candidate for HCC carrying p53 mutation.

Growth of adult spinal cord in knifefish: Development and parametrization of a distributed model.

PubMed

Ilieş, Iulian; Sipahi, Rifat; Zupanc, Günther K H

2018-01-21

The study of indeterminate-growing organisms such as teleost fish presents a unique opportunity for improving our understanding of central nervous tissue growth during adulthood. Integrating the existing experimental data associated with this process into a theoretical framework through mathematical or computational modeling provides further research avenues through sensitivity analysis and optimization. While this type of approach has been used extensively in investigations of tumor growth, wound healing, and bone regeneration, the development of nervous tissue has been rarely studied within a modeling framework. To address this gap, the present work introduces a distributed model of spinal cord growth in the knifefish Apteronotus leptorhynchus, an established teleostean model of adult growth in the central nervous system. The proposed model incorporates two mechanisms, cell proliferation by active stem/progenitor cells and cell drift due to population pressure, both of which are subject to global constraints. A coupled reaction-diffusion equation approach was adopted to represent the densities of actively-proliferating and non-proliferating cells along the longitudinal axis of the spinal cord. Computer simulations using this model yielded biologically-feasible growth trajectories. Subsequent comparisons with whole-organism growth curves allowed the estimation of previously-unknown parameters, such as relative growth rates. Copyright © 2017 Elsevier Ltd. All rights reserved.

ARABIDOPSIS HOMOLOG of TRITHORAX1 (ATX1) is required for cell production, patterning, and morphogenesis in root development

PubMed Central

Napsucialy-Mendivil, Selene; Alvarez-Venegas, Raúl; Shishkova, Svetlana; Dubrovsky, Joseph G.

2014-01-01

ARABIDOPSIS HOMOLOG of TRITHORAX1 (ATX1/SDG27), a known regulator of flower development, encodes a H3K4histone methyltransferase that maintains a number of genes in an active state. In this study, the role of ATX1 in root development was evaluated. The loss-of-function mutant atx1-1 was impaired in primary root growth. The data suggest that ATX1 controls root growth by regulating cell cycle duration, cell production, and the transition from cell proliferation in the root apical meristem (RAM) to cell elongation. In atx1-1, the quiescent centre (QC) cells were irregular in shape and more expanded than those of the wild type. This feature, together with the atypical distribution of T-divisions, the presence of oblique divisions, and the abnormal cell patterning in the RAM, suggests a lack of coordination between cell division and cell growth in the mutant. The expression domain of QC-specific markers was expanded both in the primary RAM and in the developing lateral root primordia of atx1-1 plants. These abnormalities were independent of auxin-response gradients. ATX1 was also found to be required for lateral root initiation, morphogenesis, and emergence. The time from lateral root initiation to emergence was significantly extended in the atx1-1 mutant. Overall, these data suggest that ATX1 is involved in the timing of root development, stem cell niche maintenance, and cell patterning during primary and lateral root development. Thus, ATX1 emerges as an important player in root system architecture. PMID:25205583

Axon guidance molecules in vascular patterning.

PubMed

Adams, Ralf H; Eichmann, Anne

2010-05-01

Endothelial cells (ECs) form extensive, highly branched and hierarchically organized tubular networks in vertebrates to ensure the proper distribution of molecular and cellular cargo in the vertebrate body. The growth of this vascular system during development, tissue repair or in disease conditions involves the sprouting, migration and proliferation of endothelial cells in a process termed angiogenesis. Surprisingly, specialized ECs, so-called tip cells, which lead and guide endothelial sprouts, share many feature with another guidance structure, the axonal growth cone. Tip cells are motile, invasive and extend numerous filopodial protrusions sensing growth factors, extracellular matrix and other attractive or repulsive cues in their tissue environment. Axonal growth cones and endothelial tip cells also respond to signals belonging to the same molecular families, such as Slits and Roundabouts, Netrins and UNC5 receptors, Semaphorins, Plexins and Neuropilins, and Eph receptors and ephrin ligands. Here we summarize fundamental principles of angiogenic growth, the selection and function of tip cells and the underlying regulation by guidance cues, the Notch pathway and vascular endothelial growth factor signaling.

Prohormone convertase and autocrine growth factor mRNAs are coexpressed in small cell lung carcinoma.

PubMed

Rounseville, M P; Davis, T P

2000-08-01

A hallmark of small cell lung carcinoma (SCLC) is the expression of autocrine growth factors such as neurotensin and gastrin-releasing peptide, which bind to cellular receptors and stimulate cell division. The biological activity of autocrine growth factors requires the concurrent expression of prohormone convertases that cleave the growth factors to their active form, suggesting the expression of these genes is linked in SCLCs. RNase protection assays were used to detect the expression of autocrine growth factor and prohormone convertase mRNAs in a panel of lung cancer cell lines. These mRNAs are coexpressed in SCLC and lung carcinoid cell lines, but not in normal lung epithelium or in non-small cell lung cancers. These findings, together with earlier results from our laboratory, suggest the expression of prohormone convertases has an important role in the development and maintenance of the SCLC phenotype and that autocrine growth factor and prohormone convertase genes respond to a common transcriptional activator in SCLC.

Testicular growth and development in puberty.

PubMed

Koskenniemi, Jaakko J; Virtanen, Helena E; Toppari, Jorma

2017-06-01

To describe pubertal testicular growth in humans, changes in testicular cell populations that result in testicular growth, and the role of testosterone and gonadotrophins follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in testicular growth. When human data were not available, studies in nonhuman primates and/or rodents were used as surrogates. Testicular growth in puberty follows a sigmoidal growth curve, with a large variation in timing of testicular growth and adult testicular volume. Testicular growth early in puberty is due to increase in Sertoli cell number and length of seminiferous tubules, whereas the largest and fastest growth results from the increase in the diameter of the seminiferous tubules first due to spermatogonial proliferation and then due to the expansion of meiotic and haploid germ cells. FSH stimulates Sertoli cell and spermatogonial proliferation, whereas LH/testosterone is mandatory to complete spermatogenesis. However, FSH and LH/testosterone work in synergy and are both needed for normal spermatogenesis. Testicular growth during puberty is rapid, and mostly due to germ cell expansion and growth in seminiferous tubule diameter triggered by androgens. Pre-treatment with FSH before the induction of puberty may improve the treatment of hypogonadotropic hypogonadism, but remains to be proven.

Simulated microgravity, Mars gravity, and 2g hypergravity affect cell cycle regulation, ribosome biogenesis, and epigenetics in Arabidopsis cell cultures.

PubMed

Kamal, Khaled Y; Herranz, Raúl; van Loon, Jack J W A; Medina, F Javier

2018-04-23

Gravity is the only component of Earth environment that remained constant throughout the entire process of biological evolution. However, it is still unclear how gravity affects plant growth and development. In this study, an in vitro cell culture of Arabidopsis thaliana was exposed to different altered gravity conditions, namely simulated reduced gravity (simulated microgravity, simulated Mars gravity) and hypergravity (2g), to study changes in cell proliferation, cell growth, and epigenetics. The effects after 3, 14, and 24-hours of exposure were evaluated. The most relevant alterations were found in the 24-hour treatment, being more significant for simulated reduced gravity than hypergravity. Cell proliferation and growth were uncoupled under simulated reduced gravity, similarly, as found in meristematic cells from seedlings grown in real or simulated microgravity. The distribution of cell cycle phases was changed, as well as the levels and gene transcription of the tested cell cycle regulators. Ribosome biogenesis was decreased, according to levels and gene transcription of nucleolar proteins and the number of inactive nucleoli. Furthermore, we found alterations in the epigenetic modifications of chromatin. These results show that altered gravity effects include a serious disturbance of cell proliferation and growth, which are cellular functions essential for normal plant development.

Microarray platform affords improved product analysis in mammalian cell growth studies

PubMed Central

Li, Lingyun; Migliore, Nicole; Schaefer, Eugene; Sharfstein, Susan T.; Dordick, Jonathan S.; Linhardt, Robert J.

2014-01-01

High throughput (HT) platforms serve as cost-efficient and rapid screening method for evaluating the effect of cell culture conditions and screening of chemicals. The aim of the current study was to develop a high-throughput cell-based microarray platform to assess the effect of culture conditions on Chinese hamster ovary (CHO) cells. Specifically, growth, transgene expression and metabolism of a GS/MSX CHO cell line, which produces a therapeutic monoclonal antibody, was examined using microarray system in conjunction with conventional shake flask platform in a non-proprietary medium. The microarray system consists of 60 nl spots of cells encapsulated in alginate and separated in groups via an 8-well chamber system attached to the chip. Results show the non-proprietary medium developed allows cell growth, production and normal glycosylation of recombinant antibody and metabolism of the recombinant CHO cells in both the microarray and shake flask platforms. In addition, 10.3 mM glutamate addition to the defined base media results in lactate metabolism shift in the recombinant GS/MSX CHO cells in the shake flask platform. Ultimately, the results demonstrate that the high-throughput microarray platform has the potential to be utilized for evaluating the impact of media additives on cellular processes, such as, cell growth, metabolism and productivity. PMID:24227746

Control of asgE Expression during Growth and Development of Myxococcus xanthus

PubMed Central

Garza, Anthony G.; Harris, Baruch Z.; Greenberg, Brandon M.; Singer, Mitchell

2000-01-01

One of the earliest events in the Myxococcus xanthus developmental cycle is production of an extracellular cell density signal called A-signal (or A-factor). Previously, we showed that cells carrying an insertion in the asgE gene fail to produce normal levels of this cell-cell signal. In this study we found that expression of asgE is growth phase regulated and developmentally regulated. Several lines of evidence indicate that asgE is cotranscribed with an upstream gene during development. Using primer extension analyses, we identified two 5′ ends for this developmental transcript. The DNA sequence upstream of one 5′ end has similarity to the promoter regions of several genes that are A-signal dependent, whereas sequences located upstream of the second 5′ end show similarity to promoter elements identified for genes that are C-signal dependent. Consistent with this result is our finding that mutants failing to produce A-signal or C-signal are defective for developmental expression of asgE. In contrast to developing cells, the large majority of the asgE transcript found in vegetative cells appears to be monocistronic. This finding suggests that asgE uses different promoters for expression during vegetative growth and development. Growth phase regulation of asgE is abolished in a relA mutant, indicating that this vegetative promoter is induced by starvation. The data presented here, in combination with our previous results, indicate that the level of AsgE in vegetative cells is sufficient for this protein to carry out its function during development. PMID:11073904

Multiscale Models in the Biomechanics of Plant Growth

PubMed Central

Fozard, John A.

2015-01-01

Plant growth occurs through the coordinated expansion of tightly adherent cells, driven by regulated softening of cell walls. It is an intrinsically multiscale process, with the integrated properties of multiple cell walls shaping the whole tissue. Multiscale models encode physical relationships to bring new understanding to plant physiology and development. PMID:25729061

A structure-based extracellular matrix expansion mechanism of fibrous tissue growth.

PubMed

Kalson, Nicholas S; Lu, Yinhui; Taylor, Susan H; Starborg, Tobias; Holmes, David F; Kadler, Karl E

2015-05-20

Embryonic growth occurs predominately by an increase in cell number; little is known about growth mechanisms later in development when fibrous tissues account for the bulk of adult vertebrate mass. We present a model for fibrous tissue growth based on 3D-electron microscopy of mouse tendon. We show that the number of collagen fibrils increases during embryonic development and then remains constant during postnatal growth. Embryonic growth was explained predominately by increases in fibril number and length. Postnatal growth arose predominately from increases in fibril length and diameter. A helical crimp structure was established in embryogenesis, and persisted postnatally. The data support a model where the shape and size of tendon is determined by the number and position of embryonic fibroblasts. The collagen fibrils that these cells synthesise provide a template for postnatal growth by structure-based matrix expansion. The model has important implications for growth of other fibrous tissues and fibrosis.

In vitro propagation of male germline stem cells from piglets.

PubMed

Zheng, Yi; Tian, Xiue; Zhang, Yaqing; Qin, Jinzhou; An, Junhui; Zeng, Wenxian

2013-07-01

To study the effects of serum and growth factors on propagation of porcine male germline stem cells (MGSCs) in vitro and develop a culture system for these stem cells. Fresh testicular cells from neonatal piglets were obtained by mechanical dissociation and collagenase-trypsin digestion. After differential plating, non-adhering cells were cultured in media supplemented with different concentrations of serum (0, 1 %, 2 %, 5 %, 10 %). After 10 days of primary culture, the cells were maintained in media supplemented with different concentrations of growth factors (basic fibroblast growth factor and epidermal growth factor at 1, 5, 10 ng/ml). The number of MGSC-derived colonies with different sizes was determined in each treatment to assess the effects of serum concentrations and growth factors. The number of MGSC-derived colonies was significantly higher in the presence of 1 % rather than 10 % fetal bovine serum (FBS). Basic fibroblast growth factor (bFGF) at 1, 5 ng/ml and epidermal growth factor (EGF) at 5, 10 ng/ml significantly promoted colony formation. Immunocytochemistry, reverse transcriptase-polymerase chain reaction (RT-PCR) and xenotransplantation assays demonstrated the presence of functional stem cells in cultured cell population. In vitro propagation of porcine MGSCs could be maintained in the presence of 1 % FBS and supplementation of growth factors for 1 month.

Correlation between dielectric property by dielectrophoretic levitation and growth activity of cells exposed to electric field.

PubMed

Hakoda, Masaru; Hirota, Yusuke

2013-09-01

The purpose of this study is to develop a system analyzing cell activity by the dielectrophoresis method. Our previous studies revealed a correlation between the growth activity and dielectric property (Re[K(ω)]) of mouse hybridoma 3-2H3 cells using dielectrophoretic levitation. Furthermore, it was clarified that the differentiation activity of many stem cells could be evaluated by the Re[K(ω)] without differentiation induction. In this paper, 3-2H3 cells exposed to an alternating current (AC) electric field or a direct current (DC) electric field were cultivated, and the influence of damage by the electric field on the growth activity of the cells was examined. To evaluate the activity of the cells by measuring the Re[K(ω)], the correlation between the growth activity and the Re[K(ω)] of the cells exposed to the electric field was examined. The relations between the cell viability, growth activity, and Re[K(ω)] in the cells exposed to the AC electric field were obtained. The growth activity of the cells exposed to the AC electric field could be evaluated by the Re[K(ω)]. Furthermore, it was found that the adverse effects of the electric field on the cell viability and the growth activity were smaller in the AC electric field than the DC electric field.

Mechanical forces and their second messengers in stimulating cell growth in vitro

NASA Technical Reports Server (NTRS)

Vandenburgh, Herman H.

1992-01-01

Mechanical forces play an important role in modulating the growth of a number of different tissues including skeletal muscle, smooth muscle, cardiac muscle, bone, endothelium, epithelium, and lung. As interest increases in the molecular mechanisms by which mechanical forces are transduced into growth alterations, model systems are being developed to study these processes in tissue culture. This paper reviews the current methods available for mechanically stimulating tissue cultured cells. It then outlines some of the putative 'mechanogenic' second messengers involved in altering cell growth. Not surprisingly, many mechanogenic second messengers are the same as those involved in growth factor-induced cell growth. It is hypothesized that from an evolutionary standpoint, some second messenger systems may have initially evolved for unicellular organisms to respond to physical forces such as gravity and mechanical perturbation in their environment. As multicellular organisms came into existence, they appropriated these mechanogenic second messenger cascades for cellular regulation by growth factors.

Extracellular matrix and cell shape: potential control points for inhibition of angiogenesis

NASA Technical Reports Server (NTRS)

Ingber, D.

1991-01-01

Capillary endothelial (CE) cells require two extracellular signals in order to switch from quiescence to growth and back to differentiation during angiogenesis: soluble angiogenic factors and insoluble extracellular matrix (ECM) molecules. Soluble endothelial mitogens, such as basic fibroblast growth factor (FGF), act over large distances to trigger capillary growth, whereas ECM molecules act locally to modulate cell responsiveness to these soluble cues. Recent studies reveal that ECM molecules regulate CE cell growth and differentiation by modulating cell shape and by activating intracellular chemical signaling pathways inside the cell. Recognition of the importance of ECM and cell shape during capillary morphogenesis has led to the identification of a series of new angiogenesis inhibitors. Elucidation of the molecular mechanism of capillary regulation may result in development of even more potent angiogenesis modulators in the future.

Biological consequences and advantages of asymmetric bacterial growth.

PubMed

Kysela, David T; Brown, Pamela J B; Huang, Kerwyn Casey; Brun, Yves V

2013-01-01

Asymmetries in cell growth and division occur in eukaryotes and prokaryotes alike. Even seemingly simple and morphologically symmetric cell division processes belie inherent underlying asymmetries in the composition of the resulting daughter cells. We consider the types of asymmetry that arise in various bacterial cell growth and division processes, which include both conditionally activated mechanisms and constitutive, hardwired aspects of bacterial life histories. Although asymmetry disposes some cells to the deleterious effects of aging, it may also benefit populations by efficiently purging accumulated damage and rejuvenating newborn cells. Asymmetries may also generate phenotypic variation required for successful exploitation of variable environments, even when extrinsic changes outpace the capacity of cells to sense and respond to challenges. We propose specific experimental approaches to further develop our understanding of the prevalence and the ultimate importance of asymmetric bacterial growth.

Optimization of Dosing for EGFR-Mutant Non–Small Cell Lung Cancer with Evolutionary Cancer Modeling

PubMed Central

Chmielecki, Juliann; Foo, Jasmine; Oxnard, Geoffrey R.; Hutchinson, Katherine; Ohashi, Kadoaki; Somwar, Romel; Wang, Lu; Amato, Katherine R.; Arcila, Maria; Sos, Martin L.; Socci, Nicholas D.; Viale, Agnes; de Stanchina, Elisa; Ginsberg, Michelle S.; Thomas, Roman K.; Kris, Mark G.; Inoue, Akira; Ladanyi, Marc; Miller, Vincent A.; Michor, Franziska; Pao, William

2012-01-01

Non–small cell lung cancers (NSCLCs) that harbor mutations within the epidermal growth factor receptor (EGFR) gene are sensitive to the tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib. Unfortunately, all patients treated with these drugs will acquire resistance, most commonly as a result of a secondary mutation within EGFR (T790M). Because both drugs were developed to target wild-type EGFR, we hypothesized that current dosing schedules were not optimized for mutant EGFR or to prevent resistance. To investigate this further, we developed isogenic TKI-sensitive and TKI-resistant pairs of cell lines that mimic the behavior of human tumors. We determined that the drug-sensitive and drug-resistant EGFR-mutant cells exhibited differential growth kinetics, with the drug-resistant cells showing slower growth. We incorporated these data into evolutionary mathematical cancer models with constraints derived from clinical data sets. This modeling predicted alternative therapeutic strategies that could prolong the clinical benefit of TKIs against EGFR-mutant NSCLCs by delaying the development of resistance. PMID:21734175

Architectural transitions in Vibrio cholerae biofilms at single-cell resolution

PubMed Central

Drescher, Knut; Dunkel, Jörn; Nadell, Carey D.; van Teeffelen, Sven; Grnja, Ivan; Wingreen, Ned S.; Stone, Howard A.; Bassler, Bonnie L.

2016-01-01

Many bacterial species colonize surfaces and form dense 3D structures, known as biofilms, which are highly tolerant to antibiotics and constitute one of the major forms of bacterial biomass on Earth. Bacterial biofilms display remarkable changes during their development from initial attachment to maturity, yet the cellular architecture that gives rise to collective biofilm morphology during growth is largely unknown. Here, we use high-resolution optical microscopy to image all individual cells in Vibrio cholerae biofilms at different stages of development, including colonies that range in size from 2 to 4,500 cells. From these data, we extracted the precise 3D cellular arrangements, cell shapes, sizes, and global morphological features during biofilm growth on submerged glass substrates under flow. We discovered several critical transitions of the internal and external biofilm architectures that separate the major phases of V. cholerae biofilm growth. Optical imaging of biofilms with single-cell resolution provides a new window into biofilm formation that will prove invaluable to understanding the mechanics underlying biofilm development. PMID:26933214

Report of the Microbial Development Working Group

NASA Technical Reports Server (NTRS)

Nelson, G.

1985-01-01

In formulating ideas on the relationship of gravity to the development, growth, and reproduction of microorganisms, a rather liberal definition of microorganisms is used which includes bacteria, yeasts, protists, filamentous fungi, and single cells in culture. A principal advantage of microorganisms as experimental subjects is the rigor with which they can be defined and controlled. As single cells, each cell may be regarded as identical to the others in the population. This property applies to the morphology, physiology, and genetic parameters of the cells. The growth and development of the population is subject to precise manipulation as the nutritional requirements are known and minimal media formulations have been developed. Growth and differentiation can be manipulated in a variety of ways, such as alteration of the culture temperature and food supply, or by use of mutants. Finally, the short generation times of microorganisms provide the opportunity to conduct multigenerational studies within practical time limits and, in a similar vein, cellular responses to various stimuli or stresses are conveniently monitored because of the rapid response times of single cells.

N-myc regulates growth and fiber cell differentiation in lens development

PubMed Central

Cavalheiro, Gabriel R.; Matos-Rodrigues, Gabriel E.; Zhao, Yilin; Gomes, Anielle L.; Anand, Deepti; Predes, Danilo; de Lima, Silmara; Abreu, Jose G.; Zheng, Deyou; Lachke, Salil A.; Cvekl, Ales; Martins, Rodrigo A. P.

2017-01-01

Myc proto-oncogenes regulate diverse cellular processes during development, but their roles during morphogenesis of specific tissues are not fully understood. We found that c-myc regulates cell proliferation in mouse lens development and previous genome-wide studies suggested functional roles for N-myc in developing lens. Here, we examined the role of N-myc in mouse lens development. Genetic inactivation of N-myc in the surface ectoderm or lens vesicle impaired eye and lens growth, while "late" inactivation in lens fibers had no effect. Unexpectedly, defective growth of N-myc--deficient lenses was not associated with alterations in lens progenitor cell proliferation or survival. Notably, N-myc-deficient lens exhibited a delay in degradation of DNA in terminally differentiating lens fiber cells. RNA-sequencing analysis of N-myc--deficient lenses identified a cohort of down-regulated genes associated with fiber cell differentiation that included DNaseIIβ. Further, an integrated analysis of differentially expressed genes in N-myc-deficient lens using normal lens expression patterns of iSyTE, N-myc-binding motif analysis and molecular interaction data from the String database led to the derivation of an N-myc-based gene regulatory network in the lens. Finally, analysis of N-myc and c-myc double-deficient lens demonstrated that these Myc genes cooperate to drive lens growth prior to lens vesicle stage. Together, these findings provide evidence for exclusive and cooperative functions of Myc transcription factors in mouse lens development and identify novel mechanisms by which N-myc regulates cell differentiation during eye morphogenesis. PMID:28716713

Glial cell line-derived neurotrophic factor in combination with insulin-like growth factor 1 and basic fibroblast growth factor promote in vitro culture of goat spermatogonial stem cells.

PubMed

Bahadorani, M; Hosseini, S M; Abedi, P; Abbasi, H; Nasr-Esfahani, M H

2015-01-01

Growth factors are increasingly considered as important regulators of spermatogonial stem cells (SSCs). This study investigated the effects of various growth factors (GDNF, IGF1, bFGF, EGF and GFRalpha-1) on purification and colonization of undifferentiated goat SSCs under in vitro and in vivo conditions. Irrespective of the culture condition used, the first signs of developing colonies were observed from day 4 of culture onwards. The number of colonies developed in GDNF + IGF1 + bFGF culture condition was significantly higher than the other groups (p < 0.05). In contrast, the size of colonies developed in GDNF + EGF + LIF culture condition was significantly higher than the other groups (p < 0.05). Immunocytochemical stationing for specific biomarkers of somatic cells (vimentin, alpha-inhibin and α-SMA) and spermatogonial cells (PLZF, THY 1, VASA, alpha-1 integrin, bet-1 integrin and DBA) revealed that both cell types existed in developing colonies, irrespective of the culture condition used. Even though, the relative abundance of VASA, FGFR3, OCT4, PLZF, BCL6B and THY1 transcription factors in GDNF + IGF1 + bFGF treatment group was significantly higher than the other groups (p < 0.05). Additionally, goat SSCs developed in the latter culture condition could colonize within the seminiferous tubules of the germ-cell depleted recipient mice following xenotransplantation. Obtained results demonstrated that combination of GDNF with IGF1 and bFGF promote in vitro culture of goat SSCs while precludes uncontrolled proliferation of somatic cells.

Development of maternal seed tissue in barley is mediated by regulated cell expansion and cell disintegration and coordinated with endosperm growth.

PubMed

Radchuk, Volodymyr; Weier, Diana; Radchuk, Ruslana; Weschke, Winfriede; Weber, Hans

2011-01-01

After fertilization, filial grain organs are surrounded by the maternal nucellus embedded within the integuments and pericarp. Rapid early endosperm growth must be coordinated with maternal tissue development. Parameters of maternal tissue growth and development were analysed during early endosperm formation. In the pericarp, cell proliferation is accomplished around the time of fertilization, followed by cell elongation predominantly in longitudinal directions. The rapid cell expansion coincides with endosperm cellularization. Distribution of TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling)-positive nuclei reveals distinct patterns starting in the nucellus at anthesis and followed later by the inner cell rows of the pericarp, then spreading to the whole pericarp. The pattern suggests timely and spatially regulated programmed cell death (PCD) processes in maternal seed tissues. When the endosperm is coenocytic, PCD events are only observed within the nucellus. Thereby, remobilization of nucellar storage compounds by PCD could nourish the early developing endosperm when functional interconnections are absent between maternal and filial seed organs. Specific proteases promote PCD events. Characterization of the barley vacuolar processing enzyme (VPE) gene family identified seven gene members specifically expressed in the developing grain. HvVPE2a (known as nucellain) together with closely similar HvVPE2b and HvVPE2d might be involved in nucellar PCD. HvVPE4 is strongly cell specific for pericarp parenchyma. Correlative evidence suggests that HvVPE4 plays a role in PCD events in the pericarp. Possible functions of PCD in the maternal tissues imply a potential nutritive role or the relief of a physical restraint for endosperm growth. PCD could also activate post-phloem transport functions.

Engineering growth factors for regenerative medicine applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitchell, Aaron C.; Briquez, Priscilla S.; Hubbell, Jeffrey A.

Growth factors are important morphogenetic proteins that instruct cell behavior and guide tissue repair and renewal. Although their therapeutic potential holds great promise in regenerative medicine applications, translation of growth factors into clinical treatments has been hindered by limitations including poor protein stability, low recombinant expression yield, and suboptimal efficacy. This review highlights current tools, technologies, and approaches to design integrated and effective growth factor-based therapies for regenerative medicine applications. The first section describes rational and combinatorial protein engineering approaches that have been utilized to improve growth factor stability, expression yield, biodistribution, and serum half-life, or alter their cell traffickingmore » behavior or receptor binding affinity. The second section highlights elegant biomaterial-based systems, inspired by the natural extracellular matrix milieu, that have been developed for effective spatial and temporal delivery of growth factors to cell surface receptors. Although appearing distinct, these two approaches are highly complementary and involve principles of molecular design and engineering to be considered in parallel when developing optimal materials for clinical applications.« less

Wnt and FGF signals interact to coordinate growth with cell fate specification during limb development.

PubMed

ten Berge, Derk; Brugmann, Samantha A; Helms, Jill A; Nusse, Roel

2008-10-01

A fundamental question in developmental biology is how does an undifferentiated field of cells acquire spatial pattern and undergo coordinated differentiation? The development of the vertebrate limb is an important paradigm for understanding these processes. The skeletal and connective tissues of the developing limb all derive from a population of multipotent progenitor cells located in its distal tip. During limb outgrowth, these progenitors segregate into a chondrogenic lineage, located in the center of the limb bud, and soft connective tissue lineages located in its periphery. We report that the interplay of two families of signaling proteins, fibroblast growth factors (FGFs) and Wnts, coordinate the growth of the multipotent progenitor cells with their simultaneous segregation into these lineages. FGF and Wnt signals act together to synergistically promote proliferation while maintaining the cells in an undifferentiated, multipotent state, but act separately to determine cell lineage specification. Withdrawal of both signals results in cell cycle withdrawal and chondrogenic differentiation. Continued exposure to Wnt, however, maintains proliferation and re-specifies the cells towards the soft connective tissue lineages. We have identified target genes that are synergistically regulated by Wnts and FGFs, and show how these factors actively suppress differentiation and promote growth. Finally, we show how the spatial restriction of Wnt and FGF signals to the limb ectoderm, and to a specialized region of it, the apical ectodermal ridge, controls the distribution of cell behaviors within the growing limb, and guides the proper spatial organization of the differentiating tissues.

Cytoskeletal changes in actin and microtubules underlie the developing surface mechanical properties of sensory and supporting cells in the mouse cochlea

PubMed Central

Szarama, Katherine B.; Gavara, Núria; Petralia, Ronald S.; Kelley, Matthew W.; Chadwick, Richard S.

2012-01-01

Correct patterning of the inner ear sensory epithelium is essential for the conversion of sound waves into auditory stimuli. Although much is known about the impact of the developing cytoskeleton on cellular growth and cell shape, considerably less is known about the role of cytoskeletal structures on cell surface mechanical properties. In this study, atomic force microscopy (AFM) was combined with fluorescence imaging to show that developing inner ear hair cells and supporting cells have different cell surface mechanical properties with different developmental time courses. We also explored the cytoskeletal organization of developing sensory and non-sensory cells, and used pharmacological modulation of cytoskeletal elements to show that the developmental increase of hair cell stiffness is a direct result of actin filaments, whereas the development of supporting cell surface mechanical properties depends on the extent of microtubule acetylation. Finally, this study found that the fibroblast growth factor signaling pathway is necessary for the developmental time course of cell surface mechanical properties, in part owing to the effects on microtubule structure. PMID:22573615

Growth Phase, Oxygen, Temperature, and Starvation Affect the Development of Viable but Non-culturable State of Vibrio cholerae.

PubMed

Wu, Bin; Liang, Weili; Kan, Biao

2016-01-01

Vibrio cholerae can enter into a viable but non-culturable (VBNC) state in order to survive in unfavorable environments. In this study, we studied the roles of five physicochemical and microbiological factors or states, namely, different strains, growth phases, oxygen, temperature, and starvation, on the development of VBNC of V. cholerae in artificial sea water (ASW). Different strains of the organism, the growth phase, and oxygen levels affected the progress of VBNC development. It was found that the VBNC state was induced faster in V. cholerae serogroup O1 classical biotype strain O395 than in O1 El Tor biotype strains C6706 and N16961. When cells in different growth phases were used for VBNC induction, stationary-phase cells lost their culturability more quickly than exponential-phase cells, while induction of a totally non-culturable state took longer to achieve for stationary-phase cells in all three strains, suggesting that heterogeneity of cells should be considered. Aeration strongly accelerated the loss of culturability. During the development of the VBNC state, the culturable cell count under aeration conditions was almost 10(6)-fold lower than under oxygen-limited conditions for all three strains. The other two factors, temperature and nutrients-rich environment, may prevent the induction of VBNC cells. At 22 or 37°C in ASW, most of the cells rapidly died and the culturable cell count reduced from about 10(8) to 10(6)-10(5) CFU/mL. The total cell counts showed that cells that lost viability were decomposed, and the viable cell counts were the same as culturable cell counts, indicating that the cells did not reach the VBNC state. VBNC state development was blocked when ASW was supplied with Luria-Bertani broth (LB), but it was not affected in ASW with M9, suggesting that specific nutrients in LB may prevent the development of VBNC state. These results revealed that the five factors evaluated in this study had different roles during the progress of VBNC induction. Changing a single factor could influence and even block the development of the VBNC state. These findings provide new insight to help design further studies to better understand the mechanisms which trigger the development and regulation of the VBNC state.

Differential Growth in Periclinal and Anticlinal Walls during Lobe Formation in Arabidopsis Cotyledon Pavement Cells.

PubMed

Armour, William J; Barton, Deborah A; Law, Andrew M K; Overall, Robyn L

2015-09-01

Lobe development in the epidermal pavement cells of Arabidopsis thaliana cotyledons and leaves is thought to take place via tip-like growth on the concave side of lobes driven by localized concentrations of actin filaments and associated proteins, with a predicted role for cortical microtubules in establishing the direction of restricted growth at the convex side. We used homologous landmarks fixed to the outer walls of pavement cells and thin-plate spline analysis to demonstrate that lobes form by differential growth of both the anticlinal and periclinal walls. Most lobes formed within the first 24 h of the cotyledons unfurling, during the period of rapid cell expansion. Cortical microtubules adjacent to the periclinal wall were persistently enriched at the convex side of lobes during development where growth was anisotropic and were less concentrated or absent at the concave side where growth was promoted. Alternating microtubule-enriched and microtubule-free zones at the periclinal wall in neighboring cells predicted sites of new lobes. There was no particular arrangement of cortical actin filaments that could predict where lobes would form. However, drug studies demonstrate that both filamentous actin and microtubules are required for lobe formation. © 2015 American Society of Plant Biologists. All rights reserved.

Derivation and application of a mathematical model for long bone growth.

PubMed

Seetharam, Suneil; Bhatia, Sujata K

2012-01-01

The objective of this work was to develop a mathematical model of long bone growth and to gain insights regarding growth disorders. A cell balance (mass balance of moving cells) assessment was performed on the three regions of the growth plate, to determine the variables (including number of proliferating cells, and division rate of proliferating cells) that influence tibia growth rate. Once this relationship was established, clinical data were used to understand how tibia growth rate and number of proliferating cells change with time. These equations were then inserted into the model to determine how cell division rate changes with time. The model was utilized to determine the influence of growth time, and to measure changes in vitamin C deficiency, Indian hedgehog (IHH) expression, and bone morphogenetic protein-2 (BMP-2) implants on tibia length. According to the model, a 10-month discrepancy in growth time between the two tibias is required to produce clinically significant leg asymmetry. In addition, vitamin C deficiency, IHH overexpression, and BMP-2 implants can all affect tibia length. These bioactive molecules have the greatest effect on tibia growth rate when these perturbations occur early in life for extended periods of time. The results are significant for modeling and predicting the effects of perturbations, including bioactive implants, on long bone growth.

Reduction of transforming growth factor-β1 expression in leukemia and its possible role in leukemia development.

PubMed

Wu, Yong; Chen, Ping; Huang, Hui-Fang; Huang, Mei-Juan; Chen, Yuan-Zhong

2012-01-01

The expression of transforming growth factor-β1 (TGF-β1) in leukemic cells and sera from patients with leukemia and its possible role in leukemia development were studied. TGF-β1 levels in culture supernatants from leukemic cells were significantly lower than those from normal bone marrow mononuclear cells. Serum TGF-β1 levels in leukemic patients were significantly lower compared with healthy controls, but returned to normal in patients achieving complete remission, and decreased when patients relapsed. TGF-β1 mRNA expression levels were significantly higher in normal bone marrow mononuclear cells but lower in leukemic cells compared with normal CD34 + cells. After transfection of the TGF-β1 gene to HL-60 cells, cell apoptosis was detected. Moreover, by flow cytometry analysis, cells arrested in G1 phase were 62% for TGF-β1 transfected cells and 44% for controls. Transfection of exogenous TGF-β1 gene inhibited HL60 cells xenograft growth in nude mice, and prolonged survival of tumor-bearing mice compared with the controls. Decreased endogenous TGF-β1 expression in leukemia cells may be involved in leukemia development, Transfection of exogenous TGF-B1 gene to HL60 can inhibit the proliferation of the cells and induce cell apoptosis by down regulating bcl-2, hTERT (human telomerase reverse transcriptase) and c-myc expression.

Building a plant cell wall at a glance.

PubMed

Lampugnani, Edwin R; Khan, Ghazanfar Abbas; Somssich, Marc; Persson, Staffan

2018-01-29

Plant cells are surrounded by a strong polysaccharide-rich cell wall that aids in determining the overall form, growth and development of the plant body. Indeed, the unique shapes of the 40-odd cell types in plants are determined by their walls, as removal of the cell wall results in spherical protoplasts that are amorphic. Hence, assembly and remodeling of the wall is essential in plant development. Most plant cell walls are composed of a framework of cellulose microfibrils that are cross-linked to each other by heteropolysaccharides. The cell walls are highly dynamic and adapt to the changing requirements of the plant during growth. However, despite the importance of plant cell walls for plant growth and for applications that we use in our daily life such as food, feed and fuel, comparatively little is known about how they are synthesized and modified. In this Cell Science at a Glance article and accompanying poster, we aim to illustrate the underpinning cell biology of the synthesis of wall carbohydrates, and their incorporation into the wall, in the model plant Arabidopsis . © 2018. Published by The Company of Biologists Ltd.

Role of bentonite clays on cell growth.

PubMed

Cervini-Silva, Javiera; Ramírez-Apan, María Teresa; Kaufhold, Stephan; Ufer, Kristian; Palacios, Eduardo; Montoya, Ascención

2016-04-01

Bentonites, naturally occurring clays, are produced industrially because of their adsorbent capacity but little is known about their effects on human health. This manuscript reports on the effect of bentonites on cell growth behaviour. Bentonites collected from India (Bent-India), Hungary (Bent-Hungary), Argentina (Bent-Argentina), and Indonesia (Bent-Indonesia) were studied. All four bentonites were screened in-vitro against two human cancer cell lines [U251 (central nervous system, glioblastoma) and SKLU-1 (lung adenocarcinoma)] supplied by the National Cancer Institute (USA). Bentonites induced growth inhibition in the presence of U251 cells, and growth increment in the presence of SKLU-1 cells, showing that interactions between bentonite and cell surfaces were highly specific. The proliferation response for U251 cells was explained because clay surfaces controlled the levels of metabolic growth components, thereby inhibiting the development of high-grade gliomas, particularly primary glioblastomas. On the other hand, the proliferation response for SKLU-1 was explained by an exacerbated growth favoured by swelling, and concomitant accumulation of solutes, and their hydration and transformation via clay-surface mediated reactions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Truncated Hormone Inhibits Breast Tumor Blood Vessel Formation, Not Tumor Growth | Center for Cancer Research

Cancer.gov

The hormone prolactin (PRL) plays a critical role in normal breast development by stimulating the proliferation of mammary cells, the production of milk proteins, and the formation of new mammary blood vessels. Unfortunately, the same cell and vessel growth pathways controlled by PRL in normal cells also operate in breast cancer cells, and elevated plasma PRL is a risk factor

Development of an efficient, non-viral transfection method for studying gene function and bone growth in human primary cranial suture mesenchymal cells reveals that the cells respond to BMP2 and BMP3.

PubMed

Dwivedi, Prem P; Anderson, Peter J; Powell, Barry C

2012-08-03

Achieving efficient introduction of plasmid DNA into primary cultures of mammalian cells is a common problem in biomedical research. Human primary cranial suture cells are derived from the connective mesenchymal tissue between the bone forming regions at the edges of the calvarial plates of the skull. Typically they are referred to as suture mesenchymal cells and are a heterogeneous population responsible for driving the rapid skull growth that occurs in utero and postnatally. To better understand the molecular mechanisms involved in skull growth, and in abnormal growth conditions, such as craniosynostosis, caused by premature bony fusion, it is essential to be able to easily introduce genes into primary bone forming cells to study their function. A comparison of several lipid-based techniques with two electroporation-based techniques demonstrated that the electroporation method known as nucleofection produced the best transfection efficiency. The parameters of nucleofection, including cell number, amount of DNA and nucleofection program, were optimized for transfection efficiency and cell survival. Two different genes and two promoter reporter vectors were used to validate the nucleofection method and the responses of human primary suture mesenchymal cells by fluorescence microscopy, RT-PCR and the dual luciferase assay. Quantification of bone morphogenetic protein (BMP) signalling using luciferase reporters demonstrated robust responses of the cells to both osteogenic BMP2 and to the anti-osteogenic BMP3. A nucleofection protocol has been developed that provides a simple and efficient, non-viral alternative method for in vitro studies of gene and protein function in human skull growth. Human primary suture mesenchymal cells exhibit robust responses to BMP2 and BMP3, and thus nucleofection can be a valuable method for studying the potential competing action of these two bone growth factors in a model system of cranial bone growth.

The Role of mTOR Signaling in the Regulation of RAG Expression and Genomic Stability During B Lymphocyte Development

DTIC Science & Technology

2014-07-01

threonine protein kinase that regulates cell growth and metabolism [1]. Mammalian TOR is inhibited by rapamycin which is potent suppressor of T cell...the development of humoral immune response(5). The mechanistic target of rapamycin (mTOR) is an evolutionarily conserved serine/ threonine protein...Sabatini. 2011. mTOR: from growth signal integration to cancer, diabetes and ageing. Nature Reviews Molecular Cell Biology 12: 21-35. 8. Edinger, A. L

Effect of soy saponin on the growth of human colon cancer cells

PubMed Central

Tsai, Cheng-Yu; Chen, Yue-Hwa; Chien, Yi-Wen; Huang, Wen-Hsuan; Lin, Shyh-Hsiang

2010-01-01

AIM: To investigate the effect of extracted soybean saponins on the growth of human colon cancer cells. METHODS: WiDr human colon cancer cells were treated with 150, 300, 600 or 1200 ppm of soy saponin to determine the effect on cell growth, cell morphology, alkaline phosphatase (AP) and protein kinase C (PKC) activities, and P53 protein, c-Fos and c-Jun gene expression. RESULTS: Soy saponin decreased the number of viable cells in a dose-dependent manner and suppressed 12-O-tetradecanol-phorbol-13-acetate-stimulated PKC activity (P < 0.05). Cells treated with saponins developed cytoplasmic vesicles and the cell membrane became rougher and more irregular in a dose-dependent manner, and eventually disassembled. At 600 and 1200 ppm, the activity of AP was increased (P < 0.05). However, the apoptosis markers such as c-Jun and c-Fos were not significantly affected by saponin. CONCLUSION: Soy saponin may be effective in preventing colon cancer by affecting cell morphology, cell proliferation enzymes, and cell growth. PMID:20632438

Growth Inhibitory Effect of Palatine Tonsil-derived Mesenchymal Stem Cells on Head and Neck Squamous Cell Carcinoma Cells

PubMed Central

Lim, Yun-Sung; Lee, Jin-Choon; Lee, Yoon Se; Wang, Soo-Geun

2012-01-01

Objectives Mesenchymal stem cells (MSCs) play an important role in the development and growth of tumor cells. However, the effect of human MSCs on the growth of human tumors is not well understood. The purpose of this study is to confirm the growth effect of palatine tonsil-derived MSCs (TD-MSCs) on head and neck squamous cell carcinoma (HNSCC) cell lines and to elucidate the mechanism of their action. Methods TD-MSCs were isolated from patient with chronic tonsillitis and tonsillar hypertrophy. Two human HNSCC cell lines (PNUH-12 and SNU-899) were studied and cocultured with isolated palatine tonsil-derived MSC. The growth inhibitory effect of MSCs on HNSCC cell lines was tested through methylthiazolyldiphenyl-tetrazolium (MTT) assay. The apoptosis induction effect of MSCs on cell lines was assessed with flow cytometry and reverse transcriptase (RT)-PCR. Results Palatine tonsil-derived MSCs exhibited a growth inhibitory effect on both cell lines. Cell cycle analysis showed an accumulation of tumor cells predominantly in G0/G1 phase with an increase in concentration of TD-MSCs, which was confirmed by increased mRNA expression of cell cycle negative regulator p21. Apoptosis of tumor cells increased significantly as concentration of cocultured TD-MSCs increased. Additionally, mRNA expression of caspase 3 was upregulated with increased concentration of TD-MSCs. Conclusion TD-MSCs have a potential growth inhibitory effect on HNSCC cell lines in vitro by inducing apoptotic cell death and G1 phase arrest of cell lines. PMID:22737289

MicroRNA-137 inhibits growth of glioblastoma through EGFR suppression

PubMed Central

Zhang, Zhenxing; Song, Xiaofeng; Tian, He; Miao, Ye; Feng, Xu; Li, Yang; Wang, Honglei

2017-01-01

Aberrant expression of certain microRNAs (miRNAs) has been shown to contribute to the development of Glioblastoma multiforme (GBM). However, the involvement of miR-137 in the carcinogenesis of GBM has not been reported. Here, we showed that miR-137 levels in GBM tissues were significantly lower than the paired normal brain tissue in patients’ specimens. Moreover, low miR-137 levels in GBM tissue were associated with poor prognosis. In vitro, overexpression of miR-137 decreased GBM cell growth and increased cell apoptosis, while depletion of miR-137 enhanced cell growth and decreased cell apoptosis. Combined bioinformatics analysis and dual luciferase reporter assay showed that miR-137 may target the 3’-UTR of the epidermal growth factor receptor (EGFR) to reduce its protein translation, resulting in suppression of EGFR signaling in GBM cells. Together, our data suggest that reduction in miR-137 levels in GBM tissues may increase cell growth and decrease cell apoptosis, possibly through suppression of EGFR. PMID:28386374

Wall mechanics and exocytosis define the shape of growth domains in fission yeast.

PubMed

Abenza, Juan F; Couturier, Etienne; Dodgson, James; Dickmann, Johanna; Chessel, Anatole; Dumais, Jacques; Carazo Salas, Rafael E

2015-10-12

The amazing structural variety of cells is matched only by their functional diversity, and reflects the complex interplay between biochemical and mechanical regulation. How both regulatory layers generate specifically shaped cellular domains is not fully understood. Here, we report how cell growth domains are shaped in fission yeast. Based on quantitative analysis of cell wall expansion and elasticity, we develop a model for how mechanics and cell wall assembly interact and use it to look for factors underpinning growth domain morphogenesis. Surprisingly, we find that neither the global cell shape regulators Cdc42-Scd1-Scd2 nor the major cell wall synthesis regulators Bgs1-Bgs4-Rgf1 are reliable predictors of growth domain geometry. Instead, their geometry can be defined by cell wall mechanics and the cortical localization pattern of the exocytic factors Sec6-Syb1-Exo70. Forceful re-directioning of exocytic vesicle fusion to broader cortical areas induces proportional shape changes to growth domains, demonstrating that both features are causally linked.

Targeting filamin A reduces K-RAS–induced lung adenocarcinomas and endothelial response to tumor growth in mice

PubMed Central

2012-01-01

Background Many human cancer cells express filamin A (FLNA), an actin-binding structural protein that interacts with a diverse set of cell signaling proteins, but little is known about the biological importance of FLNA in tumor development. FLNA is also expressed in endothelial cells, which may be important for tumor angiogenesis. In this study, we defined the impact of targeting Flna in cancer and endothelial cells on the development of tumors in vivo and on the proliferation of fibroblasts in vitro. Methods First, we used a Cre-adenovirus to simultaneously activate the expression of oncogenic K-RAS and inactivate the expression of Flna in the lung and in fibroblasts. Second, we subcutaneously injected mouse fibrosarcoma cells into mice lacking Flna in endothelial cells. Results Knockout of Flna significantly reduced K-RAS–induced lung tumor formation and the proliferation of oncogenic K-RAS–expressing fibroblasts, and attenuated the activation of the downstream signaling molecules ERK and AKT. Genetic deletion of endothelial FLNA in mice did not impact cardiovascular development; however, knockout of Flna in endothelial cells reduced subcutaneous fibrosarcoma growth and vascularity within tumors. Conclusions We conclude that FLNA is important for lung tumor growth and that endothelial Flna impacts local tumor growth. The data shed new light on the biological importance of FLNA and suggest that targeting this protein might be useful in cancer therapeutics. PMID:22857000

Anti-Cancer Activity of an Osthole Derivative, NBM-T-BMX-OS01: Targeting Vascular Endothelial Growth Factor Receptor Signaling and Angiogenesis

PubMed Central

Chiu, Pei-Ting; Ho, Shiau-Jing; Wang, Chi-Han; Chi, Chih-Chin; Huang, Yu-Han; Lee, Cheng-Feng; Li, Ying-Shiuan; Ou, George; Hsu, Ming-Jen

2013-01-01

Angiogenesis occurs during tissue growth, development and wound healing. It is also required for tumor progression and represents a rational target for therapeutic intervention. NBM-T-BMX-OS01 (BMX), derived from the semisynthesis of osthole, an active ingredient isolated from Chinese herb Cnidium monnieri (L.) Cuss., was recently shown to enhance learning and memory in rats. In this study, we characterized the anti-angiogenic activities of NBM-T-BMX-OS01 (BMX) in an effort to develop novel inhibitors to suppress angiogenesis and tumor growth. BMX inhibited vascular endothelial growth factor (VEGF)-induced proliferation, migration and endothelial tube formation in human umbilical endothelial cells (HUVECs). BMX also attenuated VEGF-induced microvessel sprouting from aortic rings ex vivo and reduced HCT116 colorectal cancer cells-induced angiogenesis in vivo. Moreover, BMX inhibited the phosphorylation of VEGFR2, FAK, Akt and ERK in HUVECs exposed to VEGF. BMX was also shown to inhibit HCT116 cell proliferation and to suppress the growth of subcutaneous xenografts of HCT116 cells in vivo. Taken together, this study provides evidence that BMX modulates vascular endothelial cell remodeling and leads to the inhibition of tumor angiogenesis. These results also support the role of BMX as a potential drug candidate and warrant the clinical development in the treatment of cancer. PMID:24312323

Beta-type transforming growth factor specifies organizational behavior in vascular smooth muscle cell cultures

PubMed Central

1987-01-01

In culture, vascular smooth muscle cells (SMC) grow in a "hill-and- valley" (multilayered) pattern of organization. We have studied the growth, behavioral organization, and biosynthetic phenotype of rat aortic SMC exposed to purified platelet-derived growth regulatory molecules. We show that multilayered growth is not a constitutive feature of cultured SMC, and that beta-type transforming growth factor (TGF-beta) is the primary determinant of multilayered growth and the hill-and-valley pattern of organization diagnostic for SMC in culture. TGF-beta inhibited, in a dose-dependent manner, the serum- or platelet- derived growth factor-mediated proliferation of these cells in two- dimensional culture, but only when cells were plated at subconfluent densities. The ability of TGF-beta to inhibit SMC growth was inversely correlated to plating cell density. When SMC were plated at monolayer density (5 X 10(4) cells/cm2) to allow maximal cell-to-cell contact, TGF-beta potentiated cell growth. This differential response of SMC to TGF-beta may contribute to the hill-and-valley pattern of organization. Unlike its effect on other cell types, TGF-beta did not enhance the synthesis of fibronectin or its incorporation into the extracellular matrix. However, the synthesis of a number of other secreted proteins was altered by TGF-beta treatment. SMC treated with TGF-beta for 4 or 8 h secreted markedly enhanced amounts of an Mr 38,000-D protein doublet whose synthesis is known to be increased by heparin (another inhibitor of SMC growth), suggesting metabolic similarities between heparin- and TGF-beta-mediated SMC growth inhibition. The data suggest that TGF-beta may play an important and complex regulatory role in SMC proliferation and organization during development and after vascular injury. PMID:3475277

Insulin-like growth factor 1 regulation of proliferation and differentiation of Xenopus laevis myogenic cells in vitro.

PubMed

Miyata, Sairi; Yada, Tomotaka; Ishikawa, Natsuko; Taheruzzaman, Kazi; Hara, Ryohei; Matsuzaki, Takashi; Nishikawa, Akio

2017-03-01

To understand the mechanism of muscle remodeling during Xenopus laevis metamorphosis, we examined the in vitro effect of insulin-like growth factor 1 (IGF-1) on growth and differentiation of three different-fate myogenic cell populations: tadpole tail, tadpole dorsal, and young adult leg muscle. IGF-1 promoted growth and differentiation of both tail and leg myogenic cells only under conditions where these cells could proliferate. Inhibition of cell proliferation by DNA synthesis inhibitor cytosine arabinoside completely canceled the IGF-1's cell differentiation promotion, suggesting the possibility that IGF-1's differentiation-promotion effect is an indirect effect via IGF-1's cell proliferation promotion. IGF-1 promoted differentiation dose dependently with maximum effect at 100-500 ng/ml. RT-PCR analysis revealed the upregulation (11-fold) of ifg1 mRNA expression in developing limbs, suggesting that IGF-1 plays a role in promoting muscle differentiation during limb development. The combined effect of triiodo-L-thyronine (T 3 ) and IGF-1 was also examined. In adult leg cells, IGF-1 promoted growth and differentiation irrespective of the presence of T 3 . In larval tail cells, cell count was 76% lower in the presence of T 3 , and IGF-1 did not promote proliferation and differentiation in T 3 -containing medium. In larval dorsal cells, cell count was also lower in the presence of T 3 , but IGF-1 enhanced proliferation and differentiation in T 3 -containing medium. This result is likely due to the presence among dorsal cells of both adult and larval types (1:1). Thus, IGF-1 affects only adult-type myogenic cells in the presence of T 3 and helps accelerate dorsal muscle remodeling during metamorphosis.

Development of novel microfluidic platforms for neural stem cell research

NASA Astrophysics Data System (ADS)

Chung, Bonggeun

This dissertation describes the development and characterization of novel microfluidic platforms to study proliferation, differentiation, migration, and apoptosis of neural stem cells (NSCs). NSCs hold tremendous promise for fundamental biological studies and cell-based therapies in human disorders. NSCs are defined as cells that can self-renew yet maintain the ability to generate the three principal cell types of the central nervous system such as neurons, astrocytes, and oligodendrocytes. NSCs therefore have therapeutic possibilities in multiple neurodevelopmental and neurodegenerative diseases. Despite their promise, cell-based therapies are limited by the inability to precisely control their behavior in culture. Compared to traditional culture tools, microfluidic platforms can provide much greater control over cell microenvironments and optimize proliferation and differentiation conditions of cells exposed to combinatorial mixtures of growth factors. Human NSCs were cultured for more than 1 week in the microfluidic device while constantly exposed to a continuous gradient of a growth factor mixture. NSCs proliferated and differentiated in a graded and proportional fashion that varied directly with growth factor concentration. In parallel to the study of growth and differentiation of NSCs, we are interested in proliferation and apoptosis of mouse NSCs exposed to morphogen gradients. Morphogen gradients are fundamental to animal brain development. Nonetheless, much controversy remains about the mechanisms by which morphogen gradients act on the developing brain. To overcome limitations of in-vitro models of gradients, we have developed a hybrid microfluidic platform that can mimic morphogen gradient profiles. Bone morphogenetic protein (BMP) activity in the developing cortex is graded and cortical NSC responses to BMPs are highly dependent on concentration and gradient slope of BMPs. To make novel microfluidic devices integrated with multiple functions, we have also developed a microfluidic multi-injector (MMI) that can generate temporal and spatial concentration gradients. MMI consists of fluidic channels and control channels with pneumatically actuated on-chip barrier valves. Repetitive actuations of on-chip valves control pulsatile release of solution that establishes microscopic chemical gradients. The development of novel gradient-generating microfluidic platforms will help in advancing our understanding of brain development and provide a versatile tool with basic and applied studies in stem cell biology.

Predicting the impact of combined therapies on myeloma cell growth using a hybrid multi-scale agent-based model.

PubMed

Ji, Zhiwei; Su, Jing; Wu, Dan; Peng, Huiming; Zhao, Weiling; Nlong Zhao, Brian; Zhou, Xiaobo

2017-01-31

Multiple myeloma is a malignant still incurable plasma cell disorder. This is due to refractory disease relapse, immune impairment, and development of multi-drug resistance. The growth of malignant plasma cells is dependent on the bone marrow (BM) microenvironment and evasion of the host's anti-tumor immune response. Hence, we hypothesized that targeting tumor-stromal cell interaction and endogenous immune system in BM will potentially improve the response of multiple myeloma (MM). Therefore, we proposed a computational simulation of the myeloma development in the complicated microenvironment which includes immune cell components and bone marrow stromal cells and predicted the effects of combined treatment with multi-drugs on myeloma cell growth. We constructed a hybrid multi-scale agent-based model (HABM) that combines an ODE system and Agent-based model (ABM). The ODEs was used for modeling the dynamic changes of intracellular signal transductions and ABM for modeling the cell-cell interactions between stromal cells, tumor, and immune components in the BM. This model simulated myeloma growth in the bone marrow microenvironment and revealed the important role of immune system in this process. The predicted outcomes were consistent with the experimental observations from previous studies. Moreover, we applied this model to predict the treatment effects of three key therapeutic drugs used for MM, and found that the combination of these three drugs potentially suppress the growth of myeloma cells and reactivate the immune response. In summary, the proposed model may serve as a novel computational platform for simulating the formation of MM and evaluating the treatment response of MM to multiple drugs.

Gamma-aminobutyric acid (GABA) stimulates pancreatic cancer growth through overexpressing GABAA receptor pi subunit.

PubMed

Takehara, Akio; Hosokawa, Masayo; Eguchi, Hidetoshi; Ohigashi, Hiroaki; Ishikawa, Osamu; Nakamura, Yusuke; Nakagawa, Hidewaki

2007-10-15

Gamma-aminobutyric acid (GABA) functions primarily as an inhibitory neurotransmitter in the mature central nervous system, and GABA/GABA receptors are also present in nonneural tissues, including cancer, but their precise function in nonneuronal or cancerous cells has thus far been poorly defined. Through the genome-wide cDNA microarray analysis of pancreatic ductal adenocarcinoma (PDAC) cells as well as subsequent reverse transcription-PCR and Northern blot analyses, we identified the overexpression of GABA receptor pi subunit (GABRP) in PDAC cells. We also found the expression of this peripheral type GABAA receptor subunit in few adult human organs. Knockdown of endogenous GABRP expression in PDAC cells by small interfering RNA attenuated PDAC cell growth, suggesting its essential role in PDAC cell viability. Notably, the addition of GABA into the cell culture medium promoted the proliferation of GABRP-expressing PDAC cells, but not GABRP-negative cells, and GABAA receptor antagonists inhibited this growth-promoting effect by GABA. The HEK293 cells constitutively expressing exogenous GABRP revealed the growth-promoting effect of GABA treatment. Furthermore, GABA treatment in GABRP-positive cells increased intracellular Ca2+ levels and activated the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/Erk) cascade. Clinical PDAC tissues contained a higher level of GABA than normal pancreas tissues due to the up-regulation of glutamate decarboxylase 1 expression, suggesting their autocrine/paracrine growth-promoting effect in PDACs. These findings imply that GABA and GABRP could play important roles in PDAC development and progression, and that this pathway can be a promising molecular target for the development of new therapeutic strategies for PDAC.

A method to generate the surface cell layer of the 3D virtual shoot apex from apical initials.

PubMed

Kucypera, Krzysztof; Lipowczan, Marcin; Piekarska-Stachowiak, Anna; Nakielski, Jerzy

2017-01-01

The development of cell pattern in the surface cell layer of the shoot apex can be investigated in vivo by use of a time-lapse confocal images, showing naked meristem in 3D in successive times. However, how this layer is originated from apical initials and develops as a result of growth and divisions of their descendants, remains unknown. This is an open area for computer modelling. A method to generate the surface cell layer is presented on the example of the 3D paraboloidal shoot apical dome. In the used model the layer originates from three apical initials that meet at the dome summit and develops through growth and cell divisions under the isotropic surface growth, defined by the growth tensor. The cells, which are described by polyhedrons, divide anticlinally with the smallest division plane that passes depending on the used mode through the cell center, or the point found randomly near this center. The formation of the surface cell pattern is described with the attention being paid to activity of the apical initials and fates of their descendants. The computer generated surface layer that included about 350 cells required about 1200 divisions of the apical initials and their derivatives. The derivatives were arranged into three more or less equal clonal sectors composed of cellular clones at different age. Each apical initial renewed itself 7-8 times to produce the sector. In the shape and location and the cellular clones the following divisions of the initial were manifested. The application of the random factor resulted in more realistic cell pattern in comparison to the pure mode. The cell divisions were analyzed statistically on the top view. When all of the division walls were considered, their angular distribution was uniform, whereas in the distribution that was limited to apical initials only, some preferences related to their arrangement at the dome summit were observed. The realistic surface cell pattern was obtained. The present method is a useful tool to generate surface cell layer, study activity of initial cells and their derivatives, and how cell expansion and division are coordinated during growth. We expect its further application to clarify the question of a number and permanence or impermanence of initial cells, and possible relationship between their shape and oriented divisions, both on the ground of the growth tensor approach.

Effects of proliferation on the decay of thermotolerance in Chinese hamster cells.

PubMed

Armour, E P; Li, G C; Hahn, G M

1985-09-01

Development and decay of thermotolerance were observed in Chinese hamster HA-1 cells. The thermotolerance kinetics of exponentially growing and fed plateau-phase cells were compared. Following a 10-min heat exposure at 45 degrees C, cells in both growth states had similar rates of development of tolerance to a subsequent 45-min exposure at 45 degrees C. This thermotolerant state started to decay between 12 and 24 hr after the initial heat exposure. The decay appeared to initiate slightly sooner in the exponentially growing cells when compared to the fed plateau-phase cells. During the decay phase, the rate of thermotolerance decay was similar in the two growth conditions. In other experiments, cells were induced to divide at a slower rate by chronic growth (3 months) in a low concentration of fetal calf serum. Under these low serum conditions cells became more sensitive to heat and the rate of decay of thermotolerance remained the same for exponentially growing cells. Plateau-phase cells were also more sensitive, but thermotolerance decayed more rapidly in these cells. Although dramatic cell cycle perturbations were seen in the exponentially growing cells, these changes appeared not to be related to thermotolerance kinetics.

Microenvironmental autophagy promotes tumour growth.

PubMed

Katheder, Nadja S; Khezri, Rojyar; O'Farrell, Fergal; Schultz, Sebastian W; Jain, Ashish; Rahman, Mohammed M; Schink, Kay O; Theodossiou, Theodossis A; Johansen, Terje; Juhász, Gábor; Bilder, David; Brech, Andreas; Stenmark, Harald; Rusten, Tor Erik

2017-01-19

As malignant tumours develop, they interact intimately with their microenvironment and can activate autophagy, a catabolic process which provides nutrients during starvation. How tumours regulate autophagy in vivo and whether autophagy affects tumour growth is controversial. Here we demonstrate, using a well characterized Drosophila melanogaster malignant tumour model, that non-cell-autonomous autophagy is induced both in the tumour microenvironment and systemically in distant tissues. Tumour growth can be pharmacologically restrained using autophagy inhibitors, and early-stage tumour growth and invasion are genetically dependent on autophagy within the local tumour microenvironment. Induction of autophagy is mediated by Drosophila tumour necrosis factor and interleukin-6-like signalling from metabolically stressed tumour cells, whereas tumour growth depends on active amino acid transport. We show that dormant growth-impaired tumours from autophagy-deficient animals reactivate tumorous growth when transplanted into autophagy-proficient hosts. We conclude that transformed cells engage surrounding normal cells as active and essential microenvironmental contributors to early tumour growth through nutrient-generating autophagy.

Oogenesis: From Oogonia to Ovulation in the Flagfish, Jordanella floridae Goode and Bean, 1879 (Teleostei: Cyprinodontidae).

PubMed

Uribe, Mari Carmen; Grier, Harry J; García-Alarcón, Adriana; Parenti, Lynne R

2016-10-01

We provide histological details of the development of oocytes in the cyprinodontid flagfish, Jordanella floridae. There are six stages of oogenesis: Oogonial proliferation, chromatin nucleolus, primary growth (previtellogenesis [PG]), secondary growth (vitellogenesis), oocyte maturation and ovulation. The ovarian lamellae are lined by a germinal epithelium composed of epithelial cells and scattered oogonia. During primary growth, the development of cortical alveoli and oil droplets, are initiated simultaneously. During secondary growth, yolk globules coalesce into a fluid mass. The full-grown oocyte contains a large globule of fluid yolk. The germinal vesicle is at the animal pole, and the cortical alveoli and oil droplets are located at the periphery. The disposition of oil droplets at the vegetal pole of the germinal vesicle during late secondary growth stage is a unique characteristic. The follicular cell layer is composed initially of a single layer of squamous cells during early PG which become columnar during early vitellogenesis. During primary and secondary growth stages, filaments develop among the follicular cells and also around the micropyle. The filaments are seen extending from the zona pellucida after ovulation. During ovulation, a space is evident between the oocyte and the zona pellucida. Asynchronous spawning activity is confirmed by the observation that, after ovulation, the ovarian lamellae contain follicles in both primary and secondary growth stages; in contrast, when the seasonal activity of oogenesis and spawning ends, after ovulation, the ovarian lamellae contain only follicles in the primary growth stage. J. Morphol. 277:1339-1354, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Vascular endothelial growth factor and nitric oxide synthase expression in human tooth germ development.

PubMed

Mastrangelo, F; Sberna, M T; Tettamanti, L; Cantatore, G; Tagliabue, A; Gherlone, E

2016-01-01

Vascular Endothelia Growth Factor (VEGF) and Nitric Oxide Synthase (NOS) expression, were evaluated in human tooth germs at two different stages of embryogenesis, to clarify the role of angiogenesis during tooth tissue differentiation and growth. Seventy-two third molar germ specimens were selected during oral surgery. Thirty-six were in the early stage and 36 in the later stage of tooth development. The samples were evaluated with Semi-quantitative Reverse Transcription-Polymerase chain Reaction analyses (RT-PcR), Western blot analysis (WB) and immunohistochemical analysis. Western blot and immunohistochemical analysis showed a VEGF and NOS 1-2-3 positive reaction in all samples analysed. VEGF high positive decrease reaction was observed in stellate reticulum cells, ameloblast and odontoblast clusters in early stage compared to later stage of tooth germ development. Comparable VEGF expression was observed in endothelial cells of early and advanced stage growth. NOS1 and NOS3 expressions showed a high increased value in stellate reticulum cells, and ameloblast and odontoblast clusters in advanced stage compared to early stage of development. The absence or only moderate positive reaction of NOS2 was detected in all the different tissues. Positive NOS2 expression showed in advanced stage of tissue development compared to early stage. The action of VEGF and NOS molecules are important mediators of angiogenesis during dental tissue development. VEGF high positive expression in stellate reticulum cells in the early stage of tooth development compared to the later stage and the other cell types, suggests a critical role of the stellate reticulum during dental embryo-morphogenesis.

Role of Multicellular Aggregates in Biofilm Formation

PubMed Central

Kragh, Kasper N.; Hutchison, Jaime B.; Melaugh, Gavin; Rodesney, Chris; Roberts, Aled E. L.; Irie, Yasuhiko; Jensen, Peter Ø.; Diggle, Stephen P.; Allen, Rosalind J.

2016-01-01

ABSTRACT In traditional models of in vitro biofilm development, individual bacterial cells seed a surface, multiply, and mature into multicellular, three-dimensional structures. Much research has been devoted to elucidating the mechanisms governing the initial attachment of single cells to surfaces. However, in natural environments and during infection, bacterial cells tend to clump as multicellular aggregates, and biofilms can also slough off aggregates as a part of the dispersal process. This makes it likely that biofilms are often seeded by aggregates and single cells, yet how these aggregates impact biofilm initiation and development is not known. Here we use a combination of experimental and computational approaches to determine the relative fitness of single cells and preformed aggregates during early development of Pseudomonas aeruginosa biofilms. We find that the relative fitness of aggregates depends markedly on the density of surrounding single cells, i.e., the level of competition for growth resources. When competition between aggregates and single cells is low, an aggregate has a growth disadvantage because the aggregate interior has poor access to growth resources. However, if competition is high, aggregates exhibit higher fitness, because extending vertically above the surface gives cells at the top of aggregates better access to growth resources. Other advantages of seeding by aggregates, such as earlier switching to a biofilm-like phenotype and enhanced resilience toward antibiotics and immune response, may add to this ecological benefit. Our findings suggest that current models of biofilm formation should be reconsidered to incorporate the role of aggregates in biofilm initiation. PMID:27006463

Dual role of interleukin-17 in pannus growth and osteoclastogenesis in rheumatoid arthritis.

PubMed

Ito, Hiroshi; Yamada, Hidehiro; Shibata, Toshiko N; Mitomi, Hirofumi; Nomoto, So; Ozaki, Shoichi

2011-02-04

In a murine model, interleukin (IL)-17 plays a critical role in the pathogenesis of arthritis. There are controversies, however, regarding whether IL-17 is a proinflammatory mediator in rheumatoid arthritis (RA). We previously established an ex vivo cellular model using synovial tissue (ST)-derived inflammatory cells, which reproduced pannus-like tissue growth and osteoclastic activity in vitro. Using this model, we investigated the effects of IL-17 on pannus growth and osteoclastogenesis in RA. Inflammatory cells that infiltrated synovial tissue from patients with RA were collected without enzyme digestion and designated as ST-derived inflammatory cells. ST-derived inflammatory cells were cultured in the presence or absence of IL-17 or indomethacin, and the morphologic changes were observed for 4 weeks. Cytokines produced in the culture supernatants were measured by using enzyme-linked immunosorbent assay kits. Osteoclastic activity was assessed by the development of resorption pits in calcium phosphate-coated slides. Exogenous addition of IL-17 dramatically enhanced the spontaneous production of IL-6 and prostaglandin E₂ (PGE₂) by the ST-derived inflammatory cells, while it had no effect on the production of tumor necrosis factor (TNF)-α and macrophage colony-stimulating factor (M-CSF). Furthermore, IL-17 did not affect the spontaneous development of pannus-like tissue growth and osteoclastic activity by the ST-derived inflammatory cells. On the other hand, IL-17 enhanced pannus-like tissue growth, the production of TNF-α and M-CSF and the development of osteoclastic activity in the presence of indomethacin, an inhibitor of endogenous prostanoid production, while exogenous addition of PGE₁ suppressed their activities. The present study suggests that IL-17 induces negative feedback regulation through the induction of PGE₂, while it stimulates proinflammatory pathways such as inflammatory cytokine production, pannus growth and osteoclastogenesis in RA.

Endoreduplication and fruit growth in tomato: evidence in favour of the karyoplasmic ratio theory.

PubMed

Chevalier, Christian; Bourdon, Matthieu; Pirrello, Julien; Cheniclet, Catherine; Gévaudant, Frédéric; Frangne, Nathalie

2014-06-01

The growth of a plant organ depends upon the developmental processes of cell division and cell expansion. The activity of cell divisions sets the number of cells that will make up the organ; the cell expansion activity then determines its final size. Among the various mechanisms that may influence the determination of cell size, endopolyploidy by means of endoreduplication appears to be of great importance in plants. Endoreduplication is widespread in plants and supports the process of differentiation of cells and organs. Its functional role in plant cells is not fully understood, although it is commonly associated with ploidy-dependent cell expansion. During the development of tomato fruit, cells from the (fleshy) pericarp tissue become highly polyploid, reaching a DNA content barely encountered in other plant species (between 2C and 512C). Recent investigations using tomato fruit development as a model provided new data in favour of the long-standing karyoplasmic ratio theory, stating that cells tend to adjust their cytoplasmic volume to the nuclear DNA content. By establishing a highly structured cellular system where multiple physiological functions are integrated, endoreduplication does act as a morphogenetic factor supporting cell growth during tomato fruit development. © The Author 2013. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

NOVEL POLYPHENOLS THAT INHIBIT COLON CANCER CELL GROWTH AFFECTING CANCER CELL METABOLISM.

PubMed

Gomez de Cedron, Marta; Vargas, Teodoro; Madrona, Andres; Jimenez, Aranza; Perez Perez, Maria Jesus; Quintela, Jose Carlos; Reglero, Guillermo; San-Felix, Ana Rosa; Ramirez de Molina, Ana

2018-06-05

New series of polyphenols with a hydrophilic galloyl based "head" and a hydrophobic N-acyl "tail", linked through a serinol moiety, have been synthesized and tested against colon cancer cell growth. Our structure activity relationship studies revealed that galloyl moieties are essential for growth inhibition. Moreover, the length of the N-acyl chain is crucial for the activity. Introduction of a (Z) double bond in the acyl chain increased the anti-cancer properties. Our findings demonstrate that 16, the most potent compound within this series, has inhibitory effects on colon cancer cell growth and metabolism (glycolysis and mitochondrial respiration) at the same time that activates AMPK and induces apoptotic cell death. Based on these results we propose that 16 might reprogram colon cancer cell metabolism through AMPK activation. This might lead to alterations on cancer cell bioenergy compromising cancer cell viability. Importantly, these anti-proliferative and pro-apoptotic effects are selective for cancer cells. Accordingly, these results indicate that 16, with an unsaturated C18 chain, might be a useful prototype for the development of novel colon cancer cell growth inhibitors affecting cell metabolism. The American Society for Pharmacology and Experimental Therapeutics.

Effect of graphene oxide ratio on the cell adhesion and growth behavior on a graphene oxide-coated silicon substrate

NASA Astrophysics Data System (ADS)

Jeong, Jin-Tak; Choi, Mun-Ki; Sim, Yumin; Lim, Jung-Taek; Kim, Gil-Sung; Seong, Maeng-Je; Hyung, Jung-Hwan; Kim, Keun Soo; Umar, Ahmad; Lee, Sang-Kwon

2016-09-01

Control of living cells on biocompatible materials or on modified substrates is important for the development of bio-applications, including biosensors and implant biomaterials. The topography and hydrophobicity of substrates highly affect cell adhesion, growth, and cell growth kinetics, which is of great importance in bio-applications. Herein, we investigate the adhesion, growth, and morphology of cultured breast cancer cells on a silicon substrate, on which graphene oxides (GO) was partially formed. By minimizing the size and amount of the GO-containing solution and the further annealing process, GO-coated Si samples were prepared which partially covered the Si substrates. The coverage of GO on Si samples decreases upon annealing. The behaviors of cells cultured on two samples have been observed, i.e. partially GO-coated Si (P-GO) and annealed partially GO-coated Si (Annealed p-GO), with a different coverage of GO. Indeed, the spreading area covered by the cells and the number of cells for a given culture period in the incubator were highly dependent on the hydrophobicity and the presence of oxygenated groups on GO and Si substrates, suggesting hydrophobicity-driven cell growth. Thus, the presented method can be used to control the cell growth via an appropriate surface modification.

Growth and development in higher plants under simulated microgravity conditions on a 3-dimensional clinostat.

PubMed

Shimazu, T; Yuda, T; Miyamoto, K; Yamashita, M; Ueda, J

2001-01-01

Growth and development of etiolated pea (Pisum sativum L. cv. Alaska) and maize (Zea mays L. cv. Golden Cross Bantam) seedlings grown under simulated microgravity conditions were intensively studied using a 3-dimensional clinostat as a simulator of weightlessness. Epicotyls of etiolated pea seedlings grown on the clinostat were the most oriented toward the direction far from cotyledons. Mesocotyls of etiolated maize seedlings grew at random and coleoptiles curved slightly during clinostat rotation. Clinostat rotation promoted the emergence of the 3rd internodes in etiolated pea seedlings, while it significantly inhibited the growth of the 1st internodes. In maize seedlings, the growth of coleoptiles was little affected by clinostat rotation, but that of mesocotyls was suppressed, and therefore, the emergence of the leaf out of coleoptile was promoted. Clinostat rotation reduced the osmotic concentration in the 1st internodes of pea seedlings, although it has little effect on the 2nd and the 3rd internodes. Clinostat rotation also reduced the osmotic concentrations in both coleoptiles and mesocotyls of maize seedlings. Cell-wall extensibilities of the 1st and the 3rd internodes of pea seedlings grown on the clinostat were significantly lower and higher as compared with those on 1 g conditions, respectively. Cell-wall extensibility of mesocotyls in seedlings grown on the clinostat also decreased. Changes in cell wall properties seem to be well correlated to the growth of each organ in pea and maize seedlings. These results suggest that the growth and development of plants is controlled under gravity on earth, and that the growth responses of higher plants to microgravity conditions are regulated by both cell-wall mechanical properties and osmotic properties of stem cells. c 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

Novel Insights into the Organization of Laticifer Cells: A Cell Comprising a Unified Whole System.

PubMed

Castelblanque, Lourdes; Balaguer, Begoña; Martí, Cristina; Rodríguez, Juan José; Orozco, Marianela; Vera, Pablo

2016-10-01

Laticifer cells are specialized plant cells that synthesize and accumulate latex. Studies on laticifers have lagged behind in recent years, and data regarding the functional role of laticifers and their fitness benefit still remain elusive. Laticifer differentiation and its impact on plant growth and development also remain to be investigated. Here, cellular, molecular, and genetic tools were developed to examine the distribution, differentiation, ontogeny, and other characteristic features, as well as the potential developmental role of laticifer cells in the latex-bearing plant Euphorbia lathyris. The organization of the laticiferous system within the E. lathyris plant body is reported, emerging as a single elongated and branched coenocytic cell, constituting the largest cell type existing in plants. We also report the ontogeny and organization of laticifer cells in the embryo and the identification of a laticifer-associated gene expression pattern. Moreover, the identification of laticifer- and latex-deficient mutants (pil mutants) allowed for the identification of distinct loci regulating laticifer differentiation, growth, and metabolic activity. Additionally, pil mutants revealed that laticifer cells appear nonessential for plant growth and development, thus pointing toward their importance, instead, for specific ecophysiological adaptations of latex-bearing plants in natural environments. © 2016 American Society of Plant Biologists. All Rights Reserved.

A Caulobacter MreB mutant with irregular cell shape exhibits compensatory widening to maintain a preferred surface area to volume ratio

PubMed Central

Harris, Leigh K.; Dye, Natalie A.; Theriot, Julie A.

2014-01-01

Summary Rod-shaped bacteria typically elongate at a uniform width. To investigate the genetic and physiological determinants involved in this process, we studied a mutation in the morphogenetic protein MreB in Caulobacter crescentus that gives rise to cells with a variable-width phenotype, where cells have regions that are both thinner and wider than wild-type. During growth, individual cells develop a balance of wide and thin regions, and mutant MreB dynamically localizes to poles and thin regions. Surprisingly, the surface area to volume ratio of these irregularly-shaped cells is, on average, very similar to wild-type. We propose that, while mutant MreB localizes to thin regions and promotes rod-like growth there, wide regions develop as a compensatory mechanism, allowing cells to maintain a wild-type-like surface area to volume ratio. To support this model, we have shown that cell widening is abrogated in growth conditions that promote higher surface area to volume ratios, and we have observed individual cells with high ratios return to wild-type levels over several hours by developing wide regions, suggesting that compensation can take place at the level of individual cells. PMID:25266768

Chlamydia trachomatis growth and development requires the activity of host Long-chain Acyl-CoA Synthetases (ACSLs).

PubMed

Recuero-Checa, Maria A; Sharma, Manu; Lau, Constance; Watkins, Paul A; Gaydos, Charlotte A; Dean, Deborah

2016-03-18

The obligate-intracellular pathogen Chlamydia trachomatis (Ct) has undergone considerable genome reduction with consequent dependence on host biosynthetic pathways, metabolites and enzymes. Long-chain acyl-CoA synthetases (ACSLs) are key host-cell enzymes that convert fatty acids (FA) into acyl-CoA for use in metabolic pathways. Here, we show that the complete host ACSL family [ACSL1 and ACSL3-6] translocates into the Ct membrane-bound vacuole, termed inclusion, and remains associated with membranes of metabolically active forms of Ct throughout development. We discovered that three different pharmacologic inhibitors of ACSL activity independently impede Ct growth in a dose-dependent fashion. Using an FA competition assay, host ACSLs were found to activate Ct branched-chain FAs, suggesting that one function of the ACSLs is to activate Ct FAs and host FAs (recruited from the cytoplasm) within the inclusion. Because the ACSL inhibitors can deplete lipid droplets (LD), we used a cell line where LD synthesis was switched off to evaluate whether LD deficiency affects Ct growth. In these cells, we found no effect on growth or on translocation of ACSLs into the inclusion. Our findings support an essential role for ACSL activation of host-cell and bacterial FAs within the inclusion to promote Ct growth and development, independent of LDs.

Use of microgravity bioreactors for development of an in vitro rat salivary gland cell culture model

NASA Technical Reports Server (NTRS)

Lewis, M. L.; Moriarity, D. M.; Campbell, P. S.

1993-01-01

During development, salivary gland (SG) cells both secrete factors which modulate cellular behavior and express specific hormone receptors. Whether SG cell growth is modulated by an autocrine epidermal growth factor (EGF) receptor-mediated signal transduction pathway is not clearly understood. SG tissue is the synthesis site for functionally distinct products including growth factors, digestive enzymes, and homeostasis maintaining factors. Historically, SG cells have proven difficult to grow and may be only maintained as limited three-dimensional ductal-type structures in collagen gels or on reconstituted basement membrane gels. A novel approach to establishing primary rat SG cultures is use of microgravity bioreactors originally designed by NASA as low-shear culture systems for predicting cell growth and differentiation in the microgravity environment of space. These completely fluid-filled bioreactors, which are oriented horizontally and rotate, have proven advantageous for Earth-based culture of three-dimensional cell assemblies, tissue-like aggregates, and glandular structures. Use of microgravity bioreactors for establishing in vitro models to investigate steroid-mediated secretion of EGF by normal SG cells may also prove useful for the investigation of cancer and other salivary gland disorders. These microgravity bioreactors promise challenging opportunities for future applications in basic and applied cell research.

Modulating the tumor microenvironment with RNA interference as a cancer treatment strategy.

PubMed

Zins, Karin; Sioud, Mouldy; Aharinejad, Seyedhossein; Lucas, Trevor; Abraham, Dietmar

2015-01-01

The tumor microenvironment is composed of accessory cells and immune cells in addition to extracellular matrix (ECM) components. The stromal compartment interacts with cancer cells in a complex crosstalk to support tumor development. Growth factors and cytokines produced by stromal cells support the growth of tumor cells and promote interaction with the vasculature to enhance tumor progression and invasion. The activation of autocrine and paracrine oncogenic signaling pathways by growth factors, cytokines, and proteases derived from both tumor cells and the stromal compartment is thought to play a major role in assisting tumor cells during metastasis. Consequently, targeting tumor-stroma interactions by RNA interference (RNAi)-based approaches is a promising strategy in the search for novel treatment modalities in human cancer. Recent advances in packaging technology including the use of polymers, peptides, liposomes, and nanoparticles to deliver small interfering RNAs (siRNAs) into target cells may overcome limitations associated with potential RNAi-based therapeutics. Newly developed nonviral gene delivery approaches have shown improved anticancer efficacy suggesting that RNAi-based therapeutics provide novel opportunities to elicit significant gene silencing and induce regression of tumor growth. This chapter summarizes our current understanding of the tumor microenvironment and highlights some potential targets for therapeutic intervention with RNAi-based cancer therapeutics.

Bone marrow-derived cultured mast cells and peritoneal mast cells as targets of a growth activity secreted by BALB/3T3 fibroblasts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jozaki, K.; Kuriu, A.; Hirota, S.

1991-03-01

When fibroblast cell lines were cultured in contact with bone marrow-derived cultured mast cells (CMC), both NIH/3T3 and BALB/3T3 cell lines supported the proliferation of CMC. In contrast, when contact between fibroblasts and CMC was prohibited by Biopore membranes or soft agar, only BALB/3T3 fibroblasts supported CMC proliferation, suggesting that BALB/3T3 but not NIH/3T3 cells secreted a significant amount of a mast cell growth activity. Moreover, the BALB/3T3-derived growth activity induced the incorporation of (3H)thymidine by CMC and the clonal growth of peritoneal mast cells in methylcellulose. The mast cell growth activity appeared to be different from interleukin 3 (IL-3)more » and interleukin 4 (IL-4), because mRNAs for these interleukins were not detectable in BALB/3T3 fibroblasts. Although mast cells are genetically deficient in tissues of W/Wv mice, CMC did develop when bone marrow cells of W/Wv mice were cultured with pokeweed mitogen-stimulated spleen cell-conditioned medium. Because BALB/3T3 fibroblast-conditioned medium (BALB-FCM) did not induce the incorporation of (3H)thymidine by W/Wv CMC, the growth activity in BALB-FCM appeared to be a ligand for the receptor encoded by the W (c-kit) locus. Because CMC and peritoneal mast cells are obtained as homogeneous suspensions rather easily, these cells may be potentially useful as targets for the fibroblast-derived mast cell growth activity.« less

Epidermal Growth Factor-Dependent Transformation by a Human EGF Receptor Proto-Oncogene

NASA Astrophysics Data System (ADS)

Velu, Thierry J.; Beguinot, Laura; Vass, William C.; Willingham, Mark C.; Merlino, Glenn T.; Pastan, Ira; Lowy, Douglas R.

1987-12-01

The epidermal growth factor (EGF) receptor gene EGFR has been placed in a retrovirus vector to examine the growth properties of cells that experimentally overproduce a full-length EGF receptor. NIH 3T3 cells transfected with the viral DNA or infected with the corresponding rescued retrovirus developed a fully transformed phenotype in vitro that required both functional EGFR expression and the presence of EGF in the growth medium. Cells expressing 4 × 105 EGF receptors formed tumors in nude mice, while control cells did not. Therefore, the EGFR retrovirus, which had a titer on NIH 3T3 cells that was greater than 107 focus-forming units per milliliter, can efficiently transfer and express this gene, and increased numbers of EGF receptors can contribute to the transformed phenotype.

Insulin receptor-mediated signaling via phospholipase C-γ regulates growth and differentiation in Drosophila.

PubMed

Murillo-Maldonado, Juan M; Zeineddine, Fouad Bou; Stock, Rachel; Thackeray, Justin; Riesgo-Escovar, Juan R

2011-01-01

Coordination between growth and patterning/differentiation is critical if appropriate final organ structure and size is to be achieved. Understanding how these two processes are regulated is therefore a fundamental and as yet incompletely answered question. Here we show through genetic analysis that the phospholipase C-γ (PLC-γ) encoded by small wing (sl) acts as such a link between growth and patterning/differentiation by modulating some MAPK outputs once activated by the insulin pathway; particularly, sl promotes growth and suppresses ectopic differentiation in the developing eye and wing, allowing cells to attain a normal size and differentiate properly. sl mutants have previously been shown to have a combination of both growth and patterning/differentiation phenotypes: small wings, ectopic wing veins, and extra R7 photoreceptor cells. We show here that PLC-γ activated by the insulin pathway participates broadly and positively during cell growth modulating EGF pathway activity, whereas in cell differentiation PLC-γ activated by the insulin receptor negatively regulates the EGF pathway. These roles require different SH2 domains of PLC-γ, and act via classic PLC-γ signaling and EGF ligand processing. By means of PLC-γ, the insulin receptor therefore modulates differentiation as well as growth. Overall, our results provide evidence that PLC-γ acts during development at a time when growth ends and differentiation begins, and is important for proper coordination of these two processes.

Growth Factors and Tension-Induced Skeletal Muscle Growth

NASA Technical Reports Server (NTRS)

Vandenburgh, Herman H.

1994-01-01

The project investigated biochemical mechanisms to enhance skeletal muscle growth, and developed a computer based mechanical cell stimulator system. The biochemicals investigated in this study were insulin/(Insulin like Growth Factor) IGF-1 and Steroids. In order to analyze which growth factors are essential for stretch-induced muscle growth in vitro, we developed a defined, serum-free medium in which the differentiated, cultured avian muscle fibers could be maintained for extended periods of time. The defined medium (muscle maintenance medium, MM medium) maintains the nitrogen balance of the myofibers for 3 to 7 days, based on myofiber diameter measurements and myosin heavy chain content. Insulin and IGF-1, but not IGF-2, induced pronounced myofiber hypertrophy when added to this medium. In 5 to 7 days, muscle fiber diameters increase by 71 % to 98% compared to untreated controls. Mechanical stimulation of the avian muscle fibers in MM medium increased the sensitivity of the cells to insulin and IGF-1, based on a leftward shift of the insulin dose/response curve for protein synthesis rates. (54). We developed a ligand binding assay for IGF-1 binding proteins and found that the avian skeletal muscle cultures produced three major species of 31, 36 and 43 kD molecular weight (54) Stretch of the myofibers was found to have no significant effect on the efflux of IGF-1 binding proteins, but addition of exogenous collagen stimulated IGF-1 binding protein production 1.5 to 5 fold. Steroid hormones have a profound effect on muscle protein turnover rates in vivo, with the stress-related glucocorticoids inducing rapid skeletal muscle atrophy while androgenic steroids induce skeletal muscle growth. Exercise in humans and animals reduces the catabolic effects of glucocorticoids and may enhance the anabolic effects of androgenic steroids on skeletal muscle. In our continuing work on the involvement of exogenrus growth factors in stretch-induced avian skeletal muscle growth, we have performed experiments to determine whether mechanical stimulation of cultured avian muscle cells alters their response to anabolic steroids or glucocorticoids. In static cultures, testosterone had no effect on muscle cell growth, but 5alpha-dihydrotestosterone and the synthetic steroid stanozolol increased cell growth by up to 18% and 30%, respectively, after a three day exposure. We completed development of a new IBM-based mechanical cell stimulator system to provide greater flexibility in operating and monitoring our experiments. Our previous long term studies on myofiber growth were designed around a perfusion system of our own design. We have recently changed to performing these studies using a modified CELLCO cartridge bioreactor system Z since it has been certified as the ground-based model for the Shuttle's Space Tissue Loss (STL) F= Cell Culture Module. The current goals of this aspect of the project are three fold: 1) to design a Z cell culture system for studying avian skeletal myofiber atrophy on the Shuttle and Space Station; 0 2) to expand the use of bioreactors to cells which do not grow in either suspension or attached to the hollow fibers; and 3) to combine the bioreactor system with our computerized mechanical cell stimulator to have a better in vitro model to study tension/gravity/stretch regulation of skeletal muscle size. Preliminary studies also reported on involved : (1) how release of tension can induce rapid atrophy of tissues cultured avian skeletal muscle cells, and (2) a mechanism to transfer and maintain avian skeletal muscle organoids in modified cartridges in the Space Tissue Loss Module.

Role of Connective Tissue Growth Factor in the Retinal Vasculature during Development and Ischemia

PubMed Central

Pi, Liya; Xia, Huiming; Liu, Jianwen; Shenoy, Anitha K.; Hauswirth, William W.; Scott, Edward W.

2011-01-01

Purpose. To investigate the function of connective tissue growth factor (CTGF), a matricellular protein of the CCN (Cyr61/CTGF/Nov) family, in retinal vasculature during development and ischemia. Methods. CTGF expression was determined using RT-PCR, immunohistochemistry, and transgenic mice carrying CTGF promoter-driven-GFP. CTGF antibody was intraocularly injected into neonates at postnatal day (P)2, and its effect on retinal angiogenesis was analyzed at P4. Transgenic animals expressing GFP regulated by the glial fibrillary acidic protein promoter were used for astrocyte visualization. Retinal vascular occlusion was introduced by rose Bengal and laser photocoagulation on chimeric mice that were reconstituted with GFP+ bone marrow cells. Vascular repair in response to VEGF-A and CTGF was analyzed. Results. A temporal increase in CTGF at both mRNA and protein levels was observed in the ganglion cell layer and inner nuclear layer during development. Endothelial cells and pericytes were identified as the main cellular sources of CTGF during retinal angiogenesis. CTGF stimulated the migration of astrocytes, retinal endothelial cells, and pericytes in vitro. Inhibition of CTGF by specific antibody affected vascular filopodial extension, growth of the superficial vascular plexus, and astrocyte remodeling. In adult mice, CTGF was prominently expressed in the perivascular cells of arteries. CTGF activated bone marrow-derived perivascular cells and promoted fibrovascular membrane formation in the laser-induced adult retinopathy model. Conclusions. CTGF is expressed in vascular beds and acts on multiple cell types. It is important for vessel growth during early retinal development and promotes the fibrovascular reaction in murine retinal ischemia after laser injury. PMID:21969300

Role of hepatocyte growth factor in the development of dendritic cells from CD34+ bone marrow cells.

PubMed

Ovali, E; Ratip, S; Kibaroglu, A; Tekelioglu, Y; Cetiner, M; Karti, S; Aydin, F; Bayik, M; Akoglu, T

2000-05-01

Hepatocyte growth factor (HGF) is known to augment the effects of stem cell factor, interleukin-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), erythropoetin, and granulocyte colony-stimulating factor, all of which are involved in hematopoiesis. HGF is also known to have a role in immune responses. The aim of this study was to investigate whether HGF is involved in the development of dendritic cells (DC) from CD34+ bone marrow cells. CD34+ cells obtained from three healthy donors were incubated in various combinations of HGF, GM-CSF, and tumor necrosis factor (TNF) for 12 days. Developing cell populations were analyzed for surface markers, morphology and functional capacities by flow cytometry, light microscopy and mixed lymphocyte reaction, respectively. Incubation with HGF alone generated greater number of dendritic cells from CD34+ bone marrow cells than incubation with GM-CSF, or a combination of GM-CSF with TNF. HGF was also found to potentiate the effect of GM-CSF on DC and monocyte development. The effects of HGF were inhibited by the concurrent use of TNF. HGF appears to be a significant factor in the development of dendritic cells from CD34+ bone marrow cells.

PHYSIOLOGY AND ENDOCRINOLOGY SYMPOSIUM:The effects of poor maternal nutrition during gestation on offspring postnatal growth and metabolism.

PubMed

Hoffman, M L; Reed, S A; Pillai, S M; Jones, A K; McFadden, K K; Zinn, S A; Govoni, K E

2017-05-01

Poor maternal nutrition during gestation has been linked to poor growth and development, metabolic dysfunction, impaired health, and reduced productivity of offspring in many species. Poor maternal nutrition can be defined as an excess or restriction of overall nutrients or specific macro- or micronutrients in the diet of the mother during gestation. Interestingly, there are several reports that both restricted- and over-feeding during gestation negatively affect offspring postnatal growth with reduced muscle and bone deposition, increased adipose accumulation, and metabolic dysregulation through reduced leptin and insulin sensitivity. Our laboratory and others have used experimental models of restricted- and over-feeding during gestation to evaluate effects on early postnatal growth of offspring. Restricted- and over-feeding during gestation alters body size, circulating growth factors, and metabolic hormones in offspring postnatally. Both restricted- and over-feeding alter muscle growth, increase lipid content in the muscle, and cause changes in expression of myogenic factors. Although the negative effects of poor maternal nutrition on offspring growth have been well characterized in recent years, the mechanisms contributing to these changes are not well established. Our laboratory has focused on elucidating these mechanisms by evaluating changes in gene and protein expression, and stem cell function. Through RNA-Seq analysis, we observed changes in expression of genes involved in protein synthesis, metabolism, cell function, and signal transduction in muscle tissue. We recently reported that satellite cells, muscle stem cells, have altered expression of myogenic factors in offspring from restricted-fed mothers. Bone marrow derived mesenchymal stem cells, multipotent cells that contribute to development and maintenance of several tissues including bone, muscle, and adipose, have a 50% reduction in cell proliferation and altered metabolism in offspring from both restricted- and over-fed mothers. These findings indicate that poor maternal nutrition may alter offspring postnatal growth by programming stem cell populations. In conclusion, poor maternal nutrition during gestation negatively affects offspring postnatal growth, potentially through impaired stem and satellite cell function. Therefore, determining the mechanisms that contribute to fetal programming is critical to identifying effective management interventions for these offspring and improving efficiency of production.

GLI pathogenesis-related 1 functions as a tumor-suppressor in lung cancer.

PubMed

Sheng, Xiumei; Bowen, Nathan; Wang, Zhengxin

2016-03-18

GLI pathogenesis-related 1 (GLIPR1) was originally identified in glioblastomas and its expression was also found to be down-regulated in prostate cancer. Functional studies revealed both growth suppression and proapoptotic activities for GLIPR1 in multiple cancer cell lines. GLIPR1's role in lung cancer has not been investigated. Protein arginine methyltransferase 5 (PRMT5) is a protein arginine methyltransferase and forms a stoichiometric complex with the WD repeat domain 77 (WDR77) protein. Both PRMT5 and WDR77 are essential for growth of lung epithelial and cancer cells. But additional gene products that interact genetically or biochemichally with PRMT5 and WDR77 in the control of lung cancer cell growth are not characterized. DNA microarray and immunostaining were used to detect GLIPR1 expression during lung development and lung tumorigenesis. GLIPR1 expression was also analyzed in the TCGA lung cancer cohort. The consequence of GLIPR1 on growth of lung cancer cells in the tissue culture and lung tumor xenografts in the nude mice was observed. We found that GLIPR1 expression is negatively associated with PRMT5/WDR77. GLIPR1 is absent in growing epithelial cells at the early stages of mouse lung development and highly expressed in the adult lung. Expression of GLIPR1 was down-regulated during lung tumorigenesis and its expression suppressed growth of lung cancer cells in the tissue culture and lung tumor xenografts in mice. GLIPR1 regulates lung cancer growth through the V-Erb-B avian erythroblastic leukemia viral oncogene homolog 3 (ErbB3). This study reveals a novel pathway that PRMT5/WDR77 regulates GLIPR1 expression to control lung cancer cell growth and GLIPR1 as a potential therapeutic agent for lung cancer.

Fibroblast growth factor receptor signaling crosstalk in skeletogenesis.

PubMed

Miraoui, Hichem; Marie, Pierre J

2010-11-02

Fibroblast growth factors (FGFs) play important roles in the control of embryonic and postnatal skeletal development by activating signaling through FGF receptors (FGFRs). Germline gain-of-function mutations in FGFR constitutively activate FGFR signaling, causing chondrocyte and osteoblast dysfunctions that result in skeletal dysplasias. Crosstalk between the FGFR pathway and other signaling cascades controls skeletal precursor cell differentiation. Genetic analyses revealed that the interplay of WNT and FGFR1 determines the fate and differentiation of mesenchymal stem cells during mouse craniofacial skeletogenesis. Additionally, interactions between FGFR signaling and other receptor tyrosine kinase networks, such as those mediated by the epidermal growth factor receptor and platelet-derived growth factor receptor α, were associated with excessive osteoblast differentiation and bone formation in the human skeletal dysplasia called craniosynostosis, which is a disorder of skull development. We review the roles of FGFR signaling and its crosstalk with other pathways in controlling skeletal cell fate and discuss how this crosstalk could be pharmacologically targeted to correct the abnormal cell phenotype in skeletal dysplasias caused by aberrant FGFR signaling.

Automated Cell Detection and Morphometry on Growth Plate Images of Mouse Bone

PubMed Central

Ascenzi, Maria-Grazia; Du, Xia; Harding, James I; Beylerian, Emily N; de Silva, Brian M; Gross, Ben J; Kastein, Hannah K; Wang, Weiguang; Lyons, Karen M; Schaeffer, Hayden

2014-01-01

Microscopy imaging of mouse growth plates is extensively used in biology to understand the effect of specific molecules on various stages of normal bone development and on bone disease. Until now, such image analysis has been conducted by manual detection. In fact, when existing automated detection techniques were applied, morphological variations across the growth plate and heterogeneity of image background color, including the faint presence of cells (chondrocytes) located deeper in tissue away from the image’s plane of focus, and lack of cell-specific features, interfered with identification of cell. We propose the first method of automated detection and morphometry applicable to images of cells in the growth plate of long bone. Through ad hoc sequential application of the Retinex method, anisotropic diffusion and thresholding, our new cell detection algorithm (CDA) addresses these challenges on bright-field microscopy images of mouse growth plates. Five parameters, chosen by the user in respect of image characteristics, regulate our CDA. Our results demonstrate effectiveness of the proposed numerical method relative to manual methods. Our CDA confirms previously established results regarding chondrocytes’ number, area, orientation, height and shape of normal growth plates. Our CDA also confirms differences previously found between the genetic mutated mouse Smad1/5CKO and its control mouse on fluorescence images. The CDA aims to aid biomedical research by increasing efficiency and consistency of data collection regarding arrangement and characteristics of chondrocytes. Our results suggest that automated extraction of data from microscopy imaging of growth plates can assist in unlocking information on normal and pathological development, key to the underlying biological mechanisms of bone growth. PMID:25525552

Calpain-Mediated positional information directs cell wall orientation to sustain plant stem cell activity, growth and development

USDA-ARS?s Scientific Manuscript database

Eukaryotic development and stem cell control depend on the integration of cell positional sensing with cell cycle control and cell wall positioning, yet few factors that directly link these events are known. The DEFECTIVE KERNEL1 (DEK1) gene encoding the unique plant calpain protein is fundamental f...

The role of microbial signals in plant growth and development

PubMed Central

Ortíz-Castro, Randy; Contreras-Cornejo, Hexon Angel; Macías-Rodríguez, Lourdes

2009-01-01

Plant growth and development involves a tight coordination of the spatial and temporal organization of cell division, cell expansion and cell differentiation. Orchestration of these events requires the exchange of signaling molecules between the root and shoot, which can be affected by both biotic and abiotic factors. The interactions that occur between plants and their associated microorganisms have long been of interest, as knowledge of these processes could lead to the development of novel agricultural applications. Plants produce a wide range of organic compounds including sugars, organic acids and vitamins, which can be used as nutrients or signals by microbial populations. On the other hand, microorganisms release phytohormones, small molecules or volatile compounds, which may act directly or indirectly to activate plant immunity or regulate plant growth and morphogenesis. In this review, we focus on recent developments in the identification of signals from free-living bacteria and fungi that interact with plants in a beneficial way. Evidence has accumulated indicating that classic plant signals such as auxins and cytokinins can be produced by microorganisms to efficiently colonize the root and modulate root system architecture. Other classes of signals, including N-acyl-L-homoserine lactones, which are used by bacteria for cell-to-cell communication, can be perceived by plants to modulate gene expression, metabolism and growth. Finally, we discuss the role played by volatile organic compounds released by certain plant growth-promoting rhizobacteria in plant immunity and developmental processes. The picture that emerges is one in which plants and microbes communicate themselves through transkingdom signaling systems involving classic and novel signals. PMID:19820333

Genetic and epigenetic instability of stem cells.

PubMed

Rajamani, Karthyayani; Li, Yuan-Sheng; Hsieh, Dean-Kuo; Lin, Shinn-Zong; Harn, Horng-Jyh; Chiou, Tzyy-Wen

2014-01-01

Recently, research on stem cells has been receiving an increasing amount of attention, both for its advantages and disadvantages. Genetic and epigenetic instabilities among stem cells have been a recurring obstacle to progress in regenerative medicine using stem cells. Various reports have stated that these instabilities can transform stem cells when transferred in vivo and thus have the potential to develop tumors. Previous research has shown that various extrinsic and intrinsic factors can contribute to the stability of stem cells. The extrinsic factors include growth supplements, growth factors, oxygen tension, passage technique, and cryopreservation. Controlling these factors based on previous reports may assist researchers in developing strategies for the production and clinical application of "safe" stem cells. On the other hand, the intrinsic factors can be unpredictable and uncontrollable; therefore, to ensure the successful use of stem cells in regenerative medicine, it is imperative to develop and implement appropriate strategies and technique for culturing stem cells and to confirm the genetic and epigenetic safety of these stem cells before employing them in clinical trials.

Using the Optical Fractionator to Estimate Total Cell Numbers in the Normal and Abnormal Developing Human Forebrain.

PubMed

Larsen, Karen B

2017-01-01

Human fetal brain development is a complex process which is vulnerable to disruption at many stages. Although histogenesis is well-documented, only a few studies have quantified cell numbers across normal human fetal brain growth. Due to the present lack of normative data it is difficult to gauge abnormal development. Furthermore, many studies of brain cell numbers have employed biased counting methods, whereas innovations in stereology during the past 20-30 years enable reliable and efficient estimates of cell numbers. However, estimates of cell volumes and densities in fetal brain samples are unreliable due to unpredictable shrinking artifacts, and the fragility of the fetal brain requires particular care in handling and processing. The optical fractionator design offers a direct and robust estimate of total cell numbers in the fetal brain with a minimum of handling of the tissue. Bearing this in mind, we have used the optical fractionator to quantify the growth of total cell numbers as a function of fetal age. We discovered a two-phased development in total cell numbers in the human fetal forebrain consisting of an initial steep rise in total cell numbers between 13 and 20 weeks of gestation, followed by a slower linear phase extending from mid-gestation to 40 weeks of gestation. Furthermore, we have demonstrated a reduced total cell number in the forebrain in fetuses with Down syndome at midgestation and in intrauterine growth-restricted fetuses during the third trimester.

C. elegans MCM-4 is a general DNA replication and checkpoint component with an epidermis-specific requirement for growth and viability.

PubMed

Korzelius, Jerome; The, Inge; Ruijtenberg, Suzan; Portegijs, Vincent; Xu, Huihong; Horvitz, H Robert; van den Heuvel, Sander

2011-02-15

DNA replication and its connection to M phase restraint are studied extensively at the level of single cells but rarely in the context of a developing animal. C. elegans lin-6 mutants lack DNA synthesis in postembryonic somatic cell lineages, while entry into mitosis continues. These mutants grow slowly and either die during larval development or develop into sterile adults. We found that lin-6 corresponds to mcm-4 and encodes an evolutionarily conserved component of the MCM2-7 pre-RC and replicative helicase complex. The MCM-4 protein is expressed in all dividing cells during embryonic and postembryonic development and associates with chromatin in late anaphase. Induction of cell cycle entry and differentiation continues in developing mcm-4 larvae, even in cells that went through abortive division. In contrast to somatic cells in mcm-4 mutants, the gonad continues DNA replication and cell division until late larval development. Expression of MCM-4 in the epidermis (also known as hypodermis) is sufficient to rescue the growth retardation and lethality of mcm-4 mutants. While the somatic gonad and germline show substantial ability to cope with lack of zygotic mcm-4 function, mcm-4 is specifically required in the epidermis for growth and survival of the whole organism. Thus, C. elegans mcm-4 has conserved functions in DNA replication and replication checkpoint control but also shows unexpected tissue-specific requirements. Copyright © 2010 Elsevier Inc. All rights reserved.

C. elegans MCM-4 is a general DNA replication and checkpoint component with an epidermis-specific requirement for growth and viability

PubMed Central

Korzelius, Jerome; The, Inge; Ruijtenberg, Suzan; Portegijs, Vincent; Xu, Huihong; Horvitz, H. Robert; van den Heuvel, Sander

2012-01-01

DNA replication and its connection to M phase restraint are studied extensively at the level of single cells but rarely in the context of a developing animal. C. elegans lin-6 mutants lack DNA synthesis in postembryonic somatic cell lineages, while entry into mitosis continues. These mutants grow slowly and either die during larval development or develop into sterile adults. We found that lin-6 corresponds to mcm-4 and encodes an evolutionarily conserved component of the MCM2-7 pre-RC and replicative helicase complex. The MCM-4 protein is expressed in all dividing cells during embryonic and postembryonic development and associates with chromatin in late anaphase. Induction of cell-cycle entry and differentiation continues in developing mcm-4 larvae, even in cells that went through abortive division. In contrast to somatic cells in mcm-4 mutants, the gonad continues DNA replication and cell division until late larval development. Expression of MCM-4 in the epidermis (also known as hypodermis) is sufficient to rescue the growth retardation and lethality of mcm-4 mutants. While the somatic gonad and germline show substantial ability to cope with lack of zygotic mcm-4 function, mcm-4 is specifically required in the epidermis for growth and survival of the whole organism. Thus, C. elegans mcm-4 has conserved functions in DNA replication and replication checkpoint control but also shows unexpected tissue-specific requirements. PMID:21146520

Regulation of microglial development: a novel role for thyroid hormone.

PubMed

Lima, F R; Gervais, A; Colin, C; Izembart, M; Neto, V M; Mallat, M

2001-03-15

The postnatal development of rat microglia is marked by an important increase in the number of microglial cells and the growth of their ramified processes. We studied the role of thyroid hormone in microglial development. The distribution and morphology of microglial cells stained with isolectin B4 or monoclonal antibody ED1 were analyzed in cortical and subcortical forebrain regions of developing rats rendered hypothyroid by prenatal and postnatal treatment with methyl-thiouracil. Microglial processes were markedly less abundant in hypothyroid pups than in age-matched normal animals, from postnatal day 4 up to the end of the third postnatal week of life. A delay in process extension and a decrease in the density of microglial cell bodies, as shown by cell counts in the developing cingulate cortex of normal and hypothyroid animals, were responsible for these differences. Conversely, neonatal rat hyperthyroidism, induced by daily injections of 3,5,3'-triiodothyronine (T3), accelerated the extension of microglial processes and increased the density of cortical microglial cell bodies above physiological levels during the first postnatal week of life. Reverse transcription-PCR and immunological analyses indicated that cultured cortical ameboid microglial cells expressed the alpha1 and beta1 isoforms of nuclear thyroid hormone receptors. Consistent with the trophic and morphogenetic effects of thyroid hormone observed in situ, T3 favored the survival of cultured purified microglial cells and the growth of their processes. These results demonstrate that thyroid hormone promotes the growth and morphological differentiation of microglia during development.

The Ornithine Decarboxylase Gene Is Essential for Cell Survival during Early Murine Development

PubMed Central

Pendeville, Hélène; Carpino, Nick; Marine, Jean-Christophe; Takahashi, Yutaka; Muller, Marc; Martial, Joseph A.; Cleveland, John L.

2001-01-01

Overexpression and inhibitor studies have suggested that the c-Myc target gene for ornithine decarboxylase (ODC), the enzyme which converts ornithine to putrescine, plays an important role in diverse biological processes, including cell growth, differentiation, transformation, and apoptosis. To explore the physiological function of ODC in mammalian development, we generated mice harboring a disrupted ODC gene. ODC-heterozygous mice were viable, normal, and fertile. Although zygotic ODC is expressed throughout the embryo prior to implantation, loss of ODC did not block normal development to the blastocyst stage. Embryonic day E3.5 ODC-deficient embryos were capable of uterine implantation and induced maternal decidualization yet failed to develop substantially thereafter. Surprisingly, analysis of ODC-deficient blastocysts suggests that loss of ODC does not affect cell growth per se but rather is required for survival of the pluripotent cells of the inner cell mass. Therefore, ODC plays an essential role in murine development, and proper homeostasis of polyamine pools appears to be required for cell survival prior to gastrulation. PMID:11533243

Development of bioengineering system for stem cell proliferation

NASA Astrophysics Data System (ADS)

Park, H. S.; Shah, R.; Shah, C.

2016-08-01

From last decades, intensive research in the field of stem cells proliferation had been promoted due to the unique property of stem cells to self-renew themselves into multiples and has potential to replicate into an organ or tissues and so it's highly demanding though challenging. Bioreactor, a mechanical device, works as a womb for stem cell proliferation by providing nutritious environment for the proper growth of stem cells. Various factors affecting stem cells growth are the bioreactor mechanism, feeding of continuous nutrients, healthy environment, etc., but it always remains a challenge for controlling biological parameters. The present paper unveils the design of mechanical device commonly known as bioreactor in tissues engineering and biotech field, use for proliferation of stem cells and imparts the proper growing condition for stem cells. This high functional bioreactor provides automation mixing of cell culture and stem cells. This design operates in conjunction with mechanism of reciprocating motion. Compare to commercial bioreactors, this proposed design is more convenient, easy to operate and less maintenance is required as bioreactor culture bag is made of polyethylene which is single use purpose. Development of this bioengineering system will be beneficial for better growth and expansion of stem cell

Testicular cell conditioned medium supports differentiation of embryonic stem cells into ovarian structures containing oocytes.

PubMed

Lacham-Kaplan, Orly; Chy, Hun; Trounson, Alan

2006-02-01

Previous reports and the current study have found that germ cell precursor cells appear in embryoid bodies (EBs) formed from mouse embryonic stem cells as identified by positive expression of specific germ cell markers such as Oct-3/4, Mvh, c-kit, Stella, and DAZL. We hypothesized that if exposed to appropriate growth factors, the germ cell precursor cells within the EBs would differentiate into gametes. The source for growth factors used in the present study is conditioned medium collected from testicular cell cultures prepared from the testes of newborn males. Testes at this stage of development contain most growth factors required for the transformation of germ stem cells into differentiated gametes. When EBs were cultured in the conditioned medium, they developed into ovarian structures, which contained putative oocytes. The oocytes were surrounded by one to two layers of flattened cells and did not have a visible zona pellucida. However, oocyte-specific markers such as Fig-alpha and ZP3 were found expressed by the ovarian structures. The production of oocytes using this method is repeatable and reliable and may be applicable to other mammalian species, including the human.

Influence of electrolytes on growth, phototropism, nutation and surface potential in etiolated cucumber seedlings

NASA Technical Reports Server (NTRS)

Spalding, E. P.; Cosgrove, D. J.

1993-01-01

A variety of electrolytes (10-30 mol m-3) increased the relative growth rate of etiolated cucumber (Cucumis sativus L. cv. Burpee's Pickler) hypocotyls by 20-50% relative to water-only controls. The nonelectrolyte mannitol inhibited growth by 10%. All salts tested were effective, regardless of chemical composition or valence. Measurements of cell-sap osmolality ruled out an osmotic mechanism for the growth stimulation by electrolytes. This, and the nonspecificity of the response, indicate that an electrical property of the solutions was responsible for their growth-stimulating activity. Measurements of surface electrical potential supported this reasoning. Treatment with electrolytes also enhanced nutation and altered the pattern of phototropic curvature development. A novel analytical method for quantitating these effects on growth was developed. The evidence indicates that electrolytes influence an electrophysiological parameter that is involved in the control of cell expansion and the coordination of growth underlying tropisms and nutations.

Insulin-like growth factor and fibroblast growth factor expression profiles in growth-restricted fetal sheep pancreas.

PubMed

Chen, Xiaochuan; Rozance, Paul J; Hay, William W; Limesand, Sean W

2012-05-01

Placental insufficiency results in intrauterine growth restriction (IUGR), impaired fetal insulin secretion and less fetal pancreatic β-cell mass, partly due to lower β-cell proliferation rates. Insulin-like growth factors (IGFs) and fibroblast growth factors (FGFs) regulate fetal β-cell proliferation and pancreas development, along with transcription factors, such as pancreatic and duodenal homeobox 1 (PDX-1). We determined expression levels for these growth factors, their receptors and IGF binding proteins in ovine fetal pancreas and isolated islets. In the IUGR pancreas, relative mRNA expression levels of IGF-I, PDX-1, FGF7 and FGFR2IIIb were 64% (P < 0.01), 76% (P < 0.05), 76% (P < 0.05) and 52% (P < 0.01) lower, respectively, compared with control fetuses. Conversely, insulin-like growth factor binding protein 2 (IGFBP-2) mRNA and protein concentrations were 2.25- and 1.2-fold greater (P < 0.05) in the IUGR pancreas compared with controls. In isolated islets from IUGR fetuses, IGF-II and IGFBP-2 mRNA concentrations were 1.5- and 3.7-fold greater (P < 0.05), and insulin mRNA was 56% less (P < 0.05) than control islets. The growth factor expression profiles for IGF and FGF signaling pathways indicate that declines in β-cell mass are due to decreased growth factor signals for both pancreatic progenitor epithelial cell and mature β-cell replication.

Apoptosis: its role in pituitary development and neoplastic pituitary tissue.

PubMed

Guzzo, M F; Carvalho, L R S; Bronstein, M D

2014-04-01

Apoptosis, also known as programmed cell death, is a phenomenon in which different stimuli trigger cellular mechanisms that culminate in death, in the absence of inflammatory cell response. Two different activation pathways are known, the intrinsic pathway (or mitochondrial) and extrinsic (or death-receptor pathway), both pathways trigger enzymatic reactions that lead cells to break up and be phagocytized by neighboring cells. This process is a common occurrence in physiological and pathological states, participating in the control of cell proliferation, differentiation and remodeling of organs. In the early steps of pituitary gland formation, numerous apoptotic cells are detected in the separation of Rathke's pouch from the roof of oral ectoderm. In the distal part of the gland, which will form the adenohypophysis, the ratio of apoptosis was significantly lower. However, there is evidence that neoplastic pituitary cells undergo unbalance in genes that control apoptosis leading to uncontrolled cell growth. No direct evidence of apoptosis was found in the drugs used for tumors producing prolactin and growth hormone. In conclusion, an unbalancing in the apoptosis process is the boundary between development and tumor growth.

AJUBA LIM Proteins Limit Hippo Activity in Proliferating Cells by Sequestering the Hippo Core Kinase Complex in the Cytosol.

PubMed

Jagannathan, Radhika; Schimizzi, Gregory V; Zhang, Kun; Loza, Andrew J; Yabuta, Norikazu; Nojima, Hitoshi; Longmore, Gregory D

2016-10-15

The Hippo pathway controls organ growth and is implicated in cancer development. Whether and how Hippo pathway activity is limited to sustain or initiate cell growth when needed is not understood. The members of the AJUBA family of LIM proteins are negative regulators of the Hippo pathway. In mammalian epithelial cells, we found that AJUBA LIM proteins limit Hippo regulation of YAP, in proliferating cells only, by sequestering a cytosolic Hippo kinase complex in which LATS kinase is inhibited. At the plasma membranes of growth-arrested cells, AJUBA LIM proteins do not inhibit or associate with the Hippo kinase complex. The ability of AJUBA LIM proteins to inhibit YAP regulation by Hippo and to associate with the kinase complex directly correlate with their capacity to limit Hippo signaling during Drosophila wing development. AJUBA LIM proteins did not influence YAP activity in response to cell-extrinsic or cell-intrinsic mechanical signals. Thus, AJUBA LIM proteins limit Hippo pathway activity in contexts where cell proliferation is needed. Copyright © 2016 Jagannathan et al.

AJUBA LIM Proteins Limit Hippo Activity in Proliferating Cells by Sequestering the Hippo Core Kinase Complex in the Cytosol

PubMed Central

Jagannathan, Radhika; Schimizzi, Gregory V.; Zhang, Kun; Loza, Andrew J.; Yabuta, Norikazu; Nojima, Hitoshi

2016-01-01

The Hippo pathway controls organ growth and is implicated in cancer development. Whether and how Hippo pathway activity is limited to sustain or initiate cell growth when needed is not understood. The members of the AJUBA family of LIM proteins are negative regulators of the Hippo pathway. In mammalian epithelial cells, we found that AJUBA LIM proteins limit Hippo regulation of YAP, in proliferating cells only, by sequestering a cytosolic Hippo kinase complex in which LATS kinase is inhibited. At the plasma membranes of growth-arrested cells, AJUBA LIM proteins do not inhibit or associate with the Hippo kinase complex. The ability of AJUBA LIM proteins to inhibit YAP regulation by Hippo and to associate with the kinase complex directly correlate with their capacity to limit Hippo signaling during Drosophila wing development. AJUBA LIM proteins did not influence YAP activity in response to cell-extrinsic or cell-intrinsic mechanical signals. Thus, AJUBA LIM proteins limit Hippo pathway activity in contexts where cell proliferation is needed. PMID:27457617

Monitoring the development of xenograft triple-negative breast cancer models using diffusion-weighted magnetic resonance imaging.

PubMed

Stephen, Renu M; Pagel, Mark D; Brown, Kathy; Baker, Amanda F; Meuillet, Emmanuelle J; Gillies, Robert J

2012-11-01

Evaluations of tumor growth rates and molecular biomarkers are traditionally used to assess new mouse models of human breast cancers. This study investigated the utility of diffusion weighted (DW)-magnetic resonance imaging (MRI) for evaluating cellular proliferation of new tumor models of triple-negative breast cancer, which may augment traditional analysis methods. Eleven human breast cancer cell lines were used to develop xenograft tumors in severe combined immunodeficient mice, with two of these cell lines exhibiting sufficient growth to be serially passaged. DW-MRI was performed to measure the distributions of the apparent diffusion coefficient (ADC) in these two tumor xenograft models, which showed a correlation with tumor growth rates and doubling times during each passage. The distributions of the ADC values were also correlated with expression of Ki67, a biomarker of cell proliferation, and hypoxia inducible factor (HIF)-1α and vascular endothelial growth factor receptor-2 (VEGFR2), which are essential proteins involved in regulating aerobic glycolysis and angiogenesis that support tumor cell proliferation. Although phosphatase and tensin homolog (PTEN) levels were different between the two xenograft models, AKT levels did not differ nor did they correlate with tumor growth. This last result demonstrates the complexity of signaling protein pathways and the difficulty in interpreting the effects of protein expression on tumor cell proliferation. In contrast, DW-MRI may be a more direct assessment of tumor growth and cancer cell proliferation.

Growth of glioblastoma is inhibited by miR-133-mediated EGFR suppression.

PubMed

Xu, Fulin; Li, Feng; Zhang, Weifeng; Jia, Pifeng

2015-12-01

Glioblastoma multiforme (GBM) is a severe and highly lethal brain cancer, which malignancy largely stems from its growing in a relatively restrained area in the brain. Hence, the understanding of the molecular regulation of the growth of GBM is critical for improving its treatment. Dysregulation of microRNAs (miRNAs) has recently been shown to contribute to the development of GBM, whereas the role of miR-133 in GBM is unknown. Here, by qualitative reverse transcription polymerase chain reaction (RT-qPCR), we detected lower miR-133 levels in GBM tissues, compared to the paired normal brain tissue. We overexpressed or inhibited miR-133 in GBM cells. Cell growth and apoptosis were analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry, respectively. We found that overexpression of miR-133 decreased GBM cell growth and increased cell apoptosis, while depletion of miR-133 increased cell growth and decreased cell apoptosis. Bioinformatic analysis was performed, showing that miR-133 may target the 3'-untranslated region (3'-UTR) of the epidermal growth factor receptor (EGFR) that transduces cell growth signals. Further, the protein translation inhibition of EGFR by miR-133 was confirmed by a dual luciferase reporter assay. Together, these data suggest that reduced miR-133 levels in GBM tissues promotes cell growth and decreases cell apoptosis, possibly through targeting mRNA of EGFR to suppress its translation.

Phytoplasmal infection derails genetically preprogrammed meristem fate and alters plant architecture

PubMed Central

Wei, Wei; Davis, Robert Edward; Nuss, Donald L.; Zhao, Yan

2013-01-01

In the life cycle of higher plants, it is the fate of meristem cells that determines the pattern of growth and development, and therefore plant morphotype and fertility. Floral transition, the turning point from vegetative growth to reproductive development, is achieved via genetically programmed sequential changes in meristem fate from vegetative to inflorescence, and to floral, leading to flower formation and eventual seed production. The transition is rarely reversible once initiated. In this communication, we report that a bacterial infection can derail the genetically programmed fate of meristem cells, thereby drastically altering the growth pattern of the host plant. We identified four characteristic symptoms in tomato plants infected with a cell wall-less bacterium, phytoplasma. The symptoms are a manifestation of the pathogen-induced alterations of growth pattern, whereas each symptom corresponds to a distinct phase in the derailment of shoot apical meristem fate. The phases include premature floral meristem termination, suppressed floral meristem initiation, delayed conversion of vegetative meristem to inflorescence meristem, and repetitive initiation and outgrowth of lateral vegetative meristems. We further found that the pathogen-induced alterations of growth pattern were correlated with transcriptional reprogramming of key meristem switching genes. Our findings open an avenue toward understanding pathological alterations in patterns of plant growth and development, thus aiding identification of molecular targets for disease control and symptom alleviation. The findings also provide insights for understanding stem cell pluripotency and raise a tantalizing possibility for using phytoplasma as a tool to dissect the course of normal plant development and to modify plant morphogenesis by manipulating meristem fate. PMID:24191032

In silico characterization of cell-cell interactions using a cellular automata model of cell culture.

PubMed

Kihara, Takanori; Kashitani, Kosuke; Miyake, Jun

2017-07-14

Cell proliferation is a key characteristic of eukaryotic cells. During cell proliferation, cells interact with each other. In this study, we developed a cellular automata model to estimate cell-cell interactions using experimentally obtained images of cultured cells. We used four types of cells; HeLa cells, human osteosarcoma (HOS) cells, rat mesenchymal stem cells (MSCs), and rat smooth muscle A7r5 cells. These cells were cultured and stained daily. The obtained cell images were binarized and clipped into squares containing about 10 4 cells. These cells showed characteristic cell proliferation patterns. The growth curves of these cells were generated from the cell proliferation images and we determined the doubling time of these cells from the growth curves. We developed a simple cellular automata system with an easily accessible graphical user interface. This system has five variable parameters, namely, initial cell number, doubling time, motility, cell-cell adhesion, and cell-cell contact inhibition (of proliferation). Within these parameters, we obtained initial cell numbers and doubling times experimentally. We set the motility at a constant value because the effect of the parameter for our simulation was restricted. Therefore, we simulated cell proliferation behavior with cell-cell adhesion and cell-cell contact inhibition as variables. By comparing growth curves and proliferation cell images, we succeeded in determining the cell-cell interaction properties of each cell. Simulated HeLa and HOS cells exhibited low cell-cell adhesion and weak cell-cell contact inhibition. Simulated MSCs exhibited high cell-cell adhesion and positive cell-cell contact inhibition. Simulated A7r5 cells exhibited low cell-cell adhesion and strong cell-cell contact inhibition. These simulated results correlated with the experimental growth curves and proliferation images. Our simulation approach is an easy method for evaluating the cell-cell interaction properties of cells.

LIM kinase function and renal growth: Potential role for LIM kinases in fetal programming of kidney development.

PubMed

Sparrow, Alexander J; Sweetman, Dylan; Welham, Simon J M

2017-10-01

Maternal dietary restriction during pregnancy impairs nephron development and results in offspring with fewer nephrons. Cell turnover in the early developing kidney is altered by exposure to maternal dietary restriction and may be regulated by the LIM-kinase family of enzymes. We set out to establish whether disturbance of LIM-kinase activity might play a role in the impairment of nephron formation. E12.5 metanephric kidneys and HK2 cells were grown in culture with the pharmacological LIM-kinase inhibitor BMS5. Organs were injected with DiI, imaged and cell numbers measured over 48h to assess growth. Cells undergoing mitosis were visualised by pH3 labelling. Growth of cultured kidneys reduced to 83% of controls after exposure to BMS5 and final cell number to 25% of control levels after 48h. Whilst control and BMS5 treated organs showed cells undergoing mitosis (100±11 cells/field vs 113±18 cells/field respectively) the proportion in anaphase was considerably diminished with BMS5 treatment (7.8±0.8% vs 0.8±0.6% respectively; P<0.01). This was consistent with effects on HK2 cells highlighting a severe impact of BMS5 on formation of the mitotic spindle and centriole positioning. DiI labelled cells migrated in 100% of control cultures vs 0% BMS5 treated organs. The number of nephrogenic precursor cells appeared depleted in whole organs and formation of new nephrons was blocked by exposure to BMS5. Pharmacological blockade of LIM-kinase function in the early developing kidney results in failure of renal development. This is likely due to prevention of dividing cells from completion of mitosis with their resultant loss. Copyright © 2017 Elsevier Inc. All rights reserved.

SOCS3 Deficiency in Myeloid Cells Promotes Tumor Development: Involvement of STAT3 Activation and Myeloid-Derived Suppressor Cells

PubMed Central

Yu, Hao; Liu, Yudong; McFarland, Braden C.; Deshane, Jessy S.; Hurst, Douglas R.; Ponnazhagan, Selvarangan; Benveniste, Etty N.; Qin, Hongwei

2015-01-01

Suppressor of cytokine signaling (SOCS) proteins are negative regulators of the JAK/STAT pathway, and generally function as tumor suppressors. The absence of SOCS3 in particular leads to heightened activation of the STAT3 transcription factor, which has a striking ability to promote tumor survival while suppressing antitumor immunity. We report for the first time that genetic deletion of SOCS3 specifically in myeloid cells significantly enhances tumor growth, which correlates with elevated levels of myeloid-derived suppressor cells (MDSC) in the tumor microenvironment, and diminished CD8+ T-cell infiltration in tumors. The importance of MDSCs in promoting tumor growth is documented by reduced tumor growth upon depletion of MDSCs. Furthermore, SOCS3-deficient bone-marrow-derived cells exhibit heightened STAT3 activation and preferentially differentiate into the Gr-1+CD11b+Ly6G+ MDSC phenotype. Importantly, we identify granulocyte colony-stimulating factor (G-CSF) as a critical factor secreted by the tumor microenvironment that promotes development of MDSCs via a STAT3-dependent pathway. Abrogation of tumor-derived G-CSF reduces the proliferation and accumulation of Gr-1+CD11b+ MDSCs and inhibits tumor growth. These findings highlight the critical function of SOCS3 as a negative regulator of MDSC development and function, via inhibition of STAT3 activation. PMID:25649351

An interaction between hepatocyte growth factor and its receptor (c-MET) prolongs the survival of chronic lymphocytic leukemic cells through STAT3 phosphorylation: a potential role of mesenchymal cells in the disease.

PubMed

Giannoni, Paolo; Scaglione, Silvia; Quarto, Rodolfo; Narcisi, Roberto; Parodi, Manuela; Balleari, Enrico; Barbieri, Federica; Pattarozzi, Alessandra; Florio, Tullio; Ferrini, Silvano; Corte, Giorgio; de Totero, Daniela

2011-07-01

Chronic lymphocytic leukemia cells are characterized by an apparent longevity in vivo which is lost when they are cultured in vitro. Cellular interactions and factors provided by the microenvironment appear essential to cell survival and may protect leukemic cells from the cytotoxicity of conventional therapies. Understanding the cross-talk between leukemic cells and stroma is of interest for identifying signals supporting disease progression and for developing novel therapeutic strategies. Different cell types, sharing a common mesenchymal origin and representative of various bone marrow components, were used to challenge the viability of leukemic cells in co-cultures and in contact-free culture systems. Using a bioinformatic approach we searched for genes shared by lineages prolonging leukemic cell survival and further analyzed their biological role in signal transduction experiments. Human bone marrow stromal cells, fibroblasts, trabecular bone-derived cells and an osteoblast-like cell line strongly enhanced survival of leukemic cells, while endothelial cells and chondrocytes did not. Gene expression profile analysis indicated two soluble factors, hepatocyte growth factor and CXCL12, as potentially involved. We demonstrated that hepatocyte growth factor and CXCL12 are produced only by mesenchymal lineages that sustain the survival of leukemic cells. Indeed chronic lymphocytic leukemic cells express a functional hepatocyte growth factor receptor (c-MET) and hepatocyte growth factor enhanced the viability of these cells through STAT3 phosphorylation, which was blocked by a c-MET tyrosine kinase inhibitor. The role of hepatocyte growth factor was confirmed by its short interfering RNA-mediated knock-down in mesenchymal cells. The finding that hepatocyte growth factor prolongs the survival of chronic lymphocytic leukemic cells is novel and we suggest that the interaction between hepatocyte growth factor-producing mesenchymal and neoplastic cells contributes to maintenance of the leukemic clone.

An interaction between hepatocyte growth factor and its receptor (c-MET) prolongs the survival of chronic lymphocytic leukemic cells through STAT3 phosphorylation: a potential role of mesenchymal cells in the disease

PubMed Central

Giannoni, Paolo; Scaglione, Silvia; Quarto, Rodolfo; Narcisi, Roberto; Parodi, Manuela; Balleari, Enrico; Barbieri, Federica; Pattarozzi, Alessandra; Florio, Tullio; Ferrini, Silvano; Corte, Giorgio; de Totero, Daniela

2011-01-01

Background Chronic lymphocytic leukemia cells are characterized by an apparent longevity in vivo which is lost when they are cultured in vitro. Cellular interactions and factors provided by the microenvironment appear essential to cell survival and may protect leukemic cells from the cytotoxicity of conventional therapies. Understanding the cross-talk between leukemic cells and stroma is of interest for identifying signals supporting disease progression and for developing novel therapeutic strategies. Design and Methods Different cell types, sharing a common mesenchymal origin and representative of various bone marrow components, were used to challenge the viability of leukemic cells in co-cultures and in contact-free culture systems. Using a bioinformatic approach we searched for genes shared by lineages prolonging leukemic cell survival and further analyzed their biological role in signal transduction experiments. Results Human bone marrow stromal cells, fibroblasts, trabecular bone-derived cells and an osteoblast-like cell line strongly enhanced survival of leukemic cells, while endothelial cells and chondrocytes did not. Gene expression profile analysis indicated two soluble factors, hepatocyte growth factor and CXCL12, as potentially involved. We demonstrated that hepatocyte growth factor and CXCL12 are produced only by mesenchymal lineages that sustain the survival of leukemic cells. Indeed chronic lymphocytic leukemic cells express a functional hepatocyte growth factor receptor (c-MET) and hepatocyte growth factor enhanced the viability of these cells through STAT3 phosphorylation, which was blocked by a c-MET tyrosine kinase inhibitor. The role of hepatocyte growth factor was confirmed by its short interfering RNA-mediated knock-down in mesenchymal cells. Conclusions The finding that hepatocyte growth factor prolongs the survival of chronic lymphocytic leukemic cells is novel and we suggest that the interaction between hepatocyte growth factor-producing mesenchymal and neoplastic cells contributes to maintenance of the leukemic clone. PMID:21486864

Elevated GnRH receptor expression plus GnRH agonist treatment inhibits the growth of a subset of papillomavirus 18-immortalized human prostate cells.

PubMed

Morgan, Kevin; Stavrou, Emmanouil; Leighton, Samuel P; Miller, Nicola; Sellar, Robin; Millar, Robert P

2011-06-15

Human metastatic prostate cancer cell growth can be inhibited by GnRH analogs but effects on virus-immortalized prostate cells have not been investigated. Virus-immortalized prostate cells were stably transfected with rat GnRH receptor cDNA and levels of GnRH binding were correlated with GnRH effects on signaling, cell cycle, growth, exosome production, and apoptosis. High levels of cell surface GnRH receptor occurred in transfected papillomavirus-immortalized WPE-1-NB26 epithelial cells but not in non-tumourigenic RWPE-1, myoepithelial WPMY-1 cells, or SV40-immortalized PNT1A. Endogenous cell surface GnRH receptor was undetectable in non-transfected cells or cancer cell lines LNCaP, PC3, and DU145. GnRH receptor levels correlated with induction of inositol phosphates, elevation of intracellular Ca(2+) , cytoskeletal actin reorganization, modulation of ERK activation and cell growth-inhibition with GnRH agonists. Hoechst 33342 DNA staining-cell sorting indicated accumulation of cells in G2 following agonist treatment. Release of exosomes from transfected WPE-1-NB26 was unaffected by agonists, unlike induction observed in HEK293([SCL60]) cells. Increased PARP cleavage and apoptotic body production were undetectable during growth-inhibition in WPE-1-NB26 cells, contrasting with HEK293([SCL60]) . EGF receptor activation inhibited GnRH-induced ERK activation in WPE-1-NB26 but growth-inhibition was not rescued by EGF or PKC inhibitor Ro320432. Growth of cells expressing low levels of GnRH receptor was not affected by agonists. Engineered high-level GnRH receptor activation inhibits growth of a subset of papillomavirus-immortalized prostate cells. Elucidating mechanisms leading to clone-specific differences in cell surface GnRH receptor levels is a valuable next step in developing strategies to exploit prostate cell anti-proliferation using GnRH agonists. Copyright © 2010 Wiley-Liss, Inc.

Cell Expansion and Endoreduplication Show a Large Genetic Variability in Pericarp and Contribute Strongly to Tomato Fruit Growth1

PubMed Central

Cheniclet, Catherine; Rong, Wen Ying; Causse, Mathilde; Frangne, Nathalie; Bolling, Laurence; Carde, Jean-Pierre; Renaudin, Jean-Pierre

2005-01-01

Postanthesis growth of tomato (Solanum lycopersicon) as of many types of fruit relies on cell division and cell expansion, so that some of the largest cells to be found in plants occur in fleshy fruit. Endoreduplication is known to occur in such materials, which suggests its involvement in cell expansion, although no data have demonstrated this hypothesis as yet. We have analyzed pattern formation, cell size, and ploidy in tomato fruit pericarp. A first set of data was collected in one cherry tomato line throughout fruit development. A second set of data was obtained from 20 tomato lines displaying a large weight range in fruit, which were compared as ovaries at anthesis and as fully grown fruit at breaker stage. A remarkable conservation of pericarp pattern, including cell layer number and cell size, is observed in all of the 20 tomato lines at anthesis, whereas large variations of growth occur afterward. A strong, positive correlation, combining development and genetic diversity, is demonstrated between mean cell size and ploidy, which holds for mean cell diameters from 10 to 350 μm (i.e. a 32,000-times volume variation) and for mean ploidy levels from 3 to 80 C. Fruit weight appears also significantly correlated with cell size and ploidy. These data provide a framework of pericarp patterning and growth. They strongly suggest the quantitative importance of polyploidy-associated cell expansion as a determinant of fruit weight in tomato. PMID:16306145

Limitation of thiamine pyrophosphate supply to growing Escherichia coli switches metabolism to efficient D-lactate formation.

PubMed

Tian, Kangming; Niu, Dandan; Liu, Xiaoguang; Prior, Bernard A; Zhou, Li; Lu, Fuping; Singh, Suren; Wang, Zhengxiang

2016-01-01

Efficient production of D-lactate by engineered Escherichia coli entails balancing cell growth and product synthesis. To develop a metabolic switch to implement a desirable transition from cell growth to product fermentation, a thiamine auxotroph B0013-080A was constructed in a highly efficient D-lactate producer E. coli strain B0013-070. This was achieved by inactivation of thiE, a gene encoding a thiamine phosphate synthase for biosynthesis of thiamine monophosphate. The resultant mutant B0013-080A failed to grow on the medium in the absence of thiamine yet growth was restored when exogenous thiamine was provided. A linear relationship between cell mass formation and amount of thiamine supplemented was mathematically determined in a shake flask experiment and confirmed in a 7-L bioreactor system. This calculation revealed that ∼ 95-96 thiamine molecules per cell were required to satisfy cell growth. This relationship was employed to develop a novel fermentation process for D-lactate production by using thiamine as a limiting condition. A D-lactate productivity of 4.11 g · L(-1) · h(-1) from glycerol under microaerobic condition and 3.66 g · L(-1) · h(-1) from glucose under anaerobic condition was achieved which is 19.1% and 10.2% higher respectively than the parental strain. These results revealed a convenient and reliable method to control cell growth and improve D-lactate fermentation. This control strategy could be applied to other biotechnological processes that require optimal allocation of carbon between cell growth and product formation. © 2015 Wiley Periodicals, Inc.

Theoretical and Experimental Study of Bacterial Colony Growth in 3D

NASA Astrophysics Data System (ADS)

Shao, Xinxian; Mugler, Andrew; Nemenman, Ilya

2014-03-01

Bacterial cells growing in liquid culture have been well studied and modeled. However, in nature, bacteria often grow as biofilms or colonies in physically structured habitats. A comprehensive model for population growth in such conditions has not yet been developed. Based on the well-established theory for bacterial growth in liquid culture, we develop a model for colony growth in 3D in which a homogeneous colony of cells locally consume a diffusing nutrient. We predict that colony growth is initially exponential, as in liquid culture, but quickly slows to sub-exponential after nutrient is locally depleted. This prediction is consistent with our experiments performed with E. coli in soft agar. Our model provides a baseline to which studies of complex growth process, such as such as spatially and phenotypically heterogeneous colonies, must be compared.

A structure-based extracellular matrix expansion mechanism of fibrous tissue growth

PubMed Central

Kalson, Nicholas S; Lu, Yinhui; Taylor, Susan H; Starborg, Tobias; Holmes, David F; Kadler, Karl E

2015-01-01

Embryonic growth occurs predominately by an increase in cell number; little is known about growth mechanisms later in development when fibrous tissues account for the bulk of adult vertebrate mass. We present a model for fibrous tissue growth based on 3D-electron microscopy of mouse tendon. We show that the number of collagen fibrils increases during embryonic development and then remains constant during postnatal growth. Embryonic growth was explained predominately by increases in fibril number and length. Postnatal growth arose predominately from increases in fibril length and diameter. A helical crimp structure was established in embryogenesis, and persisted postnatally. The data support a model where the shape and size of tendon is determined by the number and position of embryonic fibroblasts. The collagen fibrils that these cells synthesise provide a template for postnatal growth by structure-based matrix expansion. The model has important implications for growth of other fibrous tissues and fibrosis. DOI: http://dx.doi.org/10.7554/eLife.05958.001 PMID:25992598

The receptor-like kinase AtVRLK1 regulates secondary cell wall thickening.

PubMed

Huang, Cheng; Zhang, Rui; Gui, Jinshan; Zhong, Yu; Li, Laigeng

2018-04-20

During the growth and development of land plants, some specialized cells, such as tracheary elements, undergo secondary cell wall thickening. Secondary cell walls contain additional lignin, compared with primary cell walls, thus providing mechanical strength and potentially improving defenses against pathogens. However, the molecular mechanisms that initiate wall thickening are unknown. In this study, we identified an Arabidopsis thaliana leucine-rich repeat receptor-like kinase, encoded by AtVRLK1 (Vascular-Related RLK 1), that is specifically expressed in cells undergoing secondary cell wall thickening. Suppression of AtVRLK1expression resulted in a range of phenotypes that included retarded early elongation of the inflorescence stem, shorter fibers, slower root growth, and shorter flower filaments. In contrast, upregulation of AtVRLK1 led to longer fiber cells, reduced secondary cell wall thickening in fiber and vessel cells, and defects in anther dehiscence. Molecular and cellular analyses showed that downregulation of AtVRLK1 promoted secondary cell wall thickening and upregulation of AtVRLK1 enhanced cell elongation and inhibited secondary cell wall thickening. We propose that AtVRLK1 functions as a signaling component in coordinating cell elongation and cell wall thickening during growth and development. {copyright, serif} 2018 American Society of Plant Biologists. All rights reserved.

The expression of epidermal growth factor (EGF) and its receptor (EGFR) during post-natal testes development in the yak.

PubMed

Pan, Y; Cui, Y; Yu, S; Zhang, Q; Fan, J; Abdul Rasheed, B; Yang, K

2014-12-01

Growth factors play critical role in cell proliferation, regulate tissue differentiation and modulate organogenesis. Several growth factors have been identified in the testes of various mammalian species in last few years. In present investigation, the objective was to determine the expression of epidermal growth factor (EGF) and the epidermal growth factor receptor (EGFR) in yak testicular tissue by relative quantitative real time polymerase chain reaction (RT-PCR), Western blot (WB) and immunohistochemistry (IHC) from mRNA and protein levels. The testicular tissues were collected from male yak at 6 and 24 months old. Results of RT-PCR and WB showed that the expression quantity of EGF and EGFR at 24 months of age was higher than at 6 months, and the increase rate of EGFR on mRNA and protein levels was higher than the increase rate EGF during post-natal testes development. Positive staining for EGF and EGFR was very low and mainly localized to Leydig cells testes at 6 months of age with immunohistochemistry, and seminiferous tubules were not observed. At 24 month of age, both the EGF and EGFR could be detected in Leydig cells, peritubular myoid cells, sertoli cells and germ cells of the yak testes. However, EGF and EGFR were localized to preferential adluminal compartment and basal compartment in the seminiferous tubules, respectively. In conclusion, the findings in present studies suggest that EGF and EGFR as important paracrine and/or autocrine regulators in yak testes development and spermatogenesis. © 2014 Blackwell Verlag GmbH.

ONTOGENY OF PROTEINS ASSOCIATED WITH NEURITE GROWTH AND SYNAPTOGENESIS IN CEREBELLAR GRANULE CELLS IN VITRO.

EPA Science Inventory

In vitro techniques may be useful in screening for effects of developmental neurotoxicants. Previously, we characterized changes in biochemical markers associated with neuronal development in a PC12 cell model of differentiation and growth. The current research extended these stu...

Shizukaol D, a Dimeric Sesquiterpene Isolated from Chloranthus serratus, Represses the Growth of Human Liver Cancer Cells by Modulating Wnt Signalling Pathway.

PubMed

Tang, Lisha; Zhu, Hengrui; Yang, Xianmei; Xie, Fang; Peng, Jingtao; Jiang, Deke; Xie, Jun; Qi, Meiyan; Yu, Long

2016-01-01

Natural products have become sources of developing new drugs for the treatment of cancer. To seek candidate compounds that inhibit the growth of liver cancer, components of Chloranthus serratus were tested. Here, we report that shizukaol D, a dimeric sesquiterpene from Chloranthus serratus, exerted a growth inhibition effect on liver cancer cells in a dose- and time-dependent manner. We demonstrated that shizukaol D induced cells to undergo apoptosis. More importantly, shizukaol D attenuated Wnt signalling and reduced the expression of endogenous Wnt target genes, which resulted in decreased expression of β-catenin. Collectively, this study demonstrated that shizukaol D inhibited the growth of liver cancer cells by modulating Wnt pathway.

Stromal loss of TGFβ drives cancer growth in the epithelium via inflammation | Center for Cancer Research

Cancer.gov

Interactions between epithelial and stromal cells play an important role in cancer development and progression. Epithelial cancers develop when changes occur to tumor suppressor genes in stromal fibroblast cells. For example, loss of tumor suppressor, p53, in stromal fibroblasts leads to p53 inactivation in the epithelium in a prostate cancer model, and disruption of the transforming growth factor-b receptor II (TGF-βRII) in stromal fibroblasts results in intraepithelial dysplasia in prostate cancer and invasive squamous cell carcinoma (SCC) in mouse forestomach.

Reduced expression of the SHORT-ROOT gene increases the rates of growth and development in hybrid poplar and Arabidopsis.

PubMed

Wang, Jiehua; Andersson-Gunnerås, Sara; Gaboreanu, Ioana; Hertzberg, Magnus; Tucker, Matthew R; Zheng, Bo; Leśniewska, Joanna; Mellerowicz, Ewa J; Laux, Thomas; Sandberg, Göran; Jones, Brian

2011-01-01

SHORT-ROOT (SHR) is a well characterized regulator of cell division and cell fate determination in the Arabidopsis primary root. However, much less is known about the functions of SHR in the aerial parts of the plant. In this work, we cloned SHR gene from Populus trichocarpa (PtSHR1) as an AtSHR ortholog and down-regulated its expression in hybrid poplar (Populus tremula×P. tremuloides Michx-clone T89) in order to determine its physiological functions in shoot development. Sharing a 90% similarity to AtSHR at amino acid level, PtSHR1 was able to complement the Arabidopsis shr mutant. Down regulation of PtSHR1 led to a strong enhancement of primary (height) and secondary (girth) growth rates in the transgenic poplars. A similar approach in Arabidopsis showed a comparable accelerated growth and development phenotype. Our results suggest that the response to SHR could be dose-dependent and that a partial down-regulation of SHR could lead to enhanced meristem activity and a coordinated acceleration of plant growth in woody species. Therefore, SHR functions in plant growth and development as a regulator of cell division and meristem activity not only in the roots but also in the shoots. Reducing SHR expression in transgenic poplar was shown to lead to significant increases in primary and secondary growth rates. Given the current interest in bioenergy crops, SHR has a broader role as a key regulator of whole plant growth and development and SHR suppression has considerable potential for accelerating biomass accumulation in a variety of species.

Transforming Growth Factor-B Receptors in Human Breast Cancer.

DTIC Science & Technology

1998-05-01

I., Polyak, K., Iavarone, A., and Massagud, J. Kip/ Cip and Ink4 cdk inhibitors cooperate to induce cell cycle arrest in response to TGF-ß. Genes Dev...specimens. Thirdly, we have developped transient transfection assays to determine how specific TßR mutations affect affect receptor function. Using...Growth Factor-ß (TGFß) is the most potent known inhibitor of cell cycle progression of normal mammary epithelial cells; in addition, it causes cells

Truncated Hormone Inhibits Breast Tumor Blood Vessel Formation, Not Tumor Growth | Center for Cancer Research

Cancer.gov

The hormone prolactin (PRL) plays a critical role in normal breast development by stimulating the proliferation of mammary cells, the production of milk proteins, and the formation of new mammary blood vessels. Unfortunately, the same cell and vessel growth pathways controlled by PRL in normal cells also operate in breast cancer cells, and elevated plasma PRL is a risk factor for breast cancer, especially in post-menopausal women.

MSX-1 gene expression and regulation in embryonic palatal tissue.

PubMed

Nugent, P; Greene, R M

1998-01-01

The palatal cleft seen in Msx-1 knock-out mice suggests a role for this gene in normal palate development. The cleft is presumed secondary to tooth and jaw malformations, since in situ hybridization suggests that Msx-1 mRNA is not highly expressed in developing palatal tissue. In this study we demonstrate, by Northern blot analysis, the expression of Msx-1, but not Msx-2, in the developing palate and in primary cultures of murine embryonic palate mesenchymal cells. Furthermore, we propose a role for Msx-1 in retinoic acid-induced cleft palate, since retinoic acid inhibits Msx-1 mRNA expression in palate mesenchymal cells. We also demonstrate that transforming growth factor beta inhibits Msx-1 mRNA expression in palate mesenchymal cells, with retinoic acid and transforming growth factor beta acting synergistically when added simultaneously to these cells. These data suggest a mechanistic interaction between retinoic acid, transforming growth factor beta, and Msx-1 in the etiology of retinoic acid-induced cleft palate.

A droplet microfluidics platform for rapid microalgal growth and oil production analysis.

PubMed

Kim, Hyun Soo; Guzman, Adrian R; Thapa, Hem R; Devarenne, Timothy P; Han, Arum

2016-08-01

Microalgae have emerged as a promising source for producing future renewable biofuels. Developing better microalgal strains with faster growth and higher oil production rates is one of the major routes towards economically viable microalgal biofuel production. In this work, we present a droplet microfluidics-based microalgae analysis platform capable of measuring growth and oil content of various microalgal strains with single-cell resolution in a high-throughput manner. The platform allows for encapsulating a single microalgal cell into a water-in-oil emulsion droplet and tracking the growth and division of the encapsulated cell over time, followed by on-chip oil quantification. The key feature of the developed platform is its capability to fluorescently stain microalgae within microdroplets for oil content quantification. The performance of the developed platform was characterized using the unicellular microalga Chlamydomonas reinhardtii and the colonial microalga Botryococcus braunii. The application of the platform in quantifying growth and oil accumulation was successfully confirmed using C. reinhardtii under different culture conditions, namely nitrogen-replete and nitrogen-limited conditions. These results demonstrate the capability of this platform as a rapid screening tool that can be applied to a wide range of microalgal strains for analyzing growth and oil accumulation characteristics relevant to biofuel strain selection and development. Biotechnol. Bioeng. 2016;113: 1691-1701. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Effects of Gravity on Cell Movement and Development

NASA Technical Reports Server (NTRS)

Wang, Yu-Li

2002-01-01

The main purpose of this project was to understand how the migration and growth of cultured cells respond to mechanical forces. We have made significant progress on all the proposed aims. The most important discoveries are that changes in the environmental mechanical input, such as during space flight, can induce profound changes in cell migration, growth, and programmed cell death. In addition, using genetically engineered cells, we have gained important insight into the molecular mechanism underlying such mechanosensing processes. The results are summarized.

Development of the ovarian follicular epithelium.

PubMed

Rodgers, R J; Lavranos, T C; van Wezel, I L; Irving-Rodgers, H F

1999-05-25

A lot is known about the endocrine control of the development of ovarian follicles, but a key question now facing researchers is which molecular and cellular processes take part in control of follicular growth and development. The growth and development of ovarian follicles occurs postnatally and throughout adult life. In this review, we focus on the follicular epithelium (membrana granulosa) and its basal lamina. We discuss a model of how granulosa cells arise from a population of stem cells and then enter different lineages before differentiation. The structure of the epithelium at the antral stage of development is presented, and the effects that follicle growth has on the behavior of the granulosa cells are discussed. Finally, we discuss the evidence that during follicle development the follicular basal lamina changes in composition. This would be expected if the behavior of the granulosa cells changes, or if the permeability of the basal lamina changes. It will be evident that the follicular epithelium has similarities to other epithelia in the body, but that it is more dynamic, as gross changes occur during the course of follicle development. This basic information will be important for the development of future reproductive technologies in both humans and animals, and possibly for understanding polycystic ovarian syndrome in women.

Molecular targeting of growth factor receptor-bound 2 (Grb2) as an anti-cancer strategy.

PubMed

Dharmawardana, Pathirage G; Peruzzi, Benedetta; Giubellino, Alessio; Burke, Terrence R; Bottaro, Donald P

2006-01-01

Growth factor receptor-bound 2 (Grb2) is a ubiquitously expressed adapter protein that provides a critical link between cell surface growth factor receptors and the Ras signaling pathway. As such, it has been implicated in the oncogenesis of several important human malignancies. In addition to this function, research over the last decade has revealed other fundamental roles for Grb2 in cell motility and angiogenesis--processes that also contribute to tumor growth, invasiveness and metastasis. This functional profile makes Grb2 a high priority target for anti-cancer drug development. Knowledge of Grb2 protein structure, its component Src homology domains and their respective structure-function relationships has facilitated the rapid development of sophisticated drug candidates that can penetrate cells, bind Grb2 with high affinity and potently antagonize Grb2 signaling. These novel compounds offer considerable promise in our growing arsenal of rationally designed anti-cancer therapeutics.

Aerobic expression of Vitreoscilla hemoglobin improves the growth performance of CHO-K1 cells.

PubMed

Juárez, Mariana; González-De la Rosa, Claudia H; Memún, Elisa; Sigala, Juan-Carlos; Lara, Alvaro R

2017-03-01

Inefficient carbon metabolism is a relevant issue during the culture of mammalian cells for the production of biopharmaceuticals. Therefore, cell engineering strategies to improve the metabolic and growth performance of cell lines are needed. The expression of Vitreoscilla stercoraria hemoglobin (VHb) has been shown to significantly reduce overflow metabolism and improve the aerobic growth of bacteria. However, the effects of VHb on mammalian cells have been rarely studied. Here, the impact of VHb on growth and lactate accumulation during CHO-K1 cell culture was investigated. For this purpose, CHO-K1 cells were transfected with plasmids carrying the vgb or gfp gene to express VHb or green fluorescence protein (GFP), respectively. VHb expression increased the specific growth rate and biomass yields on glucose and glutamine by 60 %, and reduced the amount of lactate produced per cell by 40 %, compared to the GFP-expression controls. Immunofluorescence microscopy showed that VHb is distributed in the cytoplasm and organelles, which support the hypothesis that VHb could serve as an oxygen carrier, enhancing aerobic respiration. These results are useful for the development of better producing cell lines for industrial applications. Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study of lung-metastasized prostate cancer cell line chemotaxis to epidermal growth factor with a BIOMEMS device

NASA Astrophysics Data System (ADS)

Tata, Uday; Rao, Smitha M. N.; Sharma, Akash; Pabba, Krishna; Pokhrel, Kushal; Adhikari, Bandita; Lin, Victor K.; Chiao, J.-C.

2012-09-01

Understanding the effects of different growth factors on cancer metastasis will enable researchers to develop effective post-surgery therapeutic strategies to stop the spread of cancer. Conventional Boyden chamber assays to evaluate cell motility in metastasis studies require high volumes of reagents and are impractical for high-throughput analysis. A microfluidic device was designed for arrayed assaying of prostate cancer cell migration towards different growth factors. The device was created with polydimethylsiloxane (PDMS) and featured two wells connected by 10 micro channels. One well was for cell seeding and the other well for specific growth factors. Each channel has a width of 20 μm, a length of 1 mm and a depth of 10 μm. The device was placed on a culture dish and primed with growth media. Lung-metastasized cells in suspension of RPMI 1640 media1 supplemented with 2% of fetal bovine serum (FBS) were seeded in the cell wells. Cell culture media with epidermal growth factor (EGF) of 25, 50, 75, 100 and 125 ng ml-1 concentrations were individually added in the respective growth factor wells. A 5-day time-lapsed study of cell migration towards the chemoattractant was performed. The average numbers of cells per device in the microchannels were obtained for each attractant condition. The results indicated migration of cells increased from 50 to 100 ng ml-1 of EGF and significantly decreased at 125 ng ml-1 of EGF, as compared to control.

Development of a chick embryo heart cell for the cultivation of poliovirus.

PubMed

PRIER, J E; SULLIVAN, R

1959-04-17

An epithelial-like cell has been developed in line culture that apparently is stable. Although initially isolated cells were incapable of supporting the growth of poliovirus, the cells of the sixth and later passages allowed virus to propagate. The early, nonsusceptible cells were fibroblastic in appearance, in contrast to the epithelial type, poliovirussusceptible, derived cell of later passages.

Manipulation of the sodium-potassium ratio as a lever for controlling cell growth and improving cell specific productivity in perfusion CHO cell cultures.

PubMed

Wang, Samantha B; Lee-Goldman, Alexandria; Ravikrishnan, Janani; Zheng, Lili; Lin, Henry

2018-04-01

Perfusion processes typically require removal of a continuous or semi-continuous volume of cell culture in order to maintain a desired target cell density. For fast growing cell lines, the product loss from this stream can be upwards of 35%, significantly reducing the overall process yield. As volume removed is directly proportional to cell growth, the ability to modulate growth during perfusion cell culture production thus becomes crucial. Leveraging existing media components to achieve such control without introducing additional supplements is most desirable because it decreases process complexity and eliminates safety and clearance concerns. Here, the impact of extracellular concentrations of sodium (Na) and potassium (K) on cell growth and productivity is explored. High throughput small-scale models of perfusion revealed Na:K ratios below 1 can significantly suppress cell growth by inducing cell cycle arrest in the G0/1 phase. A concomitant increase in cell specific productivity was also observed, reaching as high as 115 pg/cell/day for one cell line studied. Multiple recombinant Chinese hamster ovary (CHO) cell lines demonstrated similar responses to lower Na:K media, indicating the universal applicability of such an approach. Product quality attributes were also assessed and revealed that effects were cell line specific, and can be acceptable or manageable depending on the phase of the drug development. Drastically altering Na and K levels in perfusion media as a lever to impact cell growth and productivity is proposed. © 2017 Wiley Periodicals, Inc.

Effect of human mesenchymal stem cells on the growth of HepG2 and Hela cells.

PubMed

Long, Xiaohui; Matsumoto, Rena; Yang, Pengyuan; Uemura, Toshimasa

2013-01-01

Human mesenchymal stem cells (hMSCs) accumulate at carcinomas and have a great impact on cancer cell's behavior. Here we demonstrated that hMSCs could display both the promotional and inhibitive effects on growth of HepG2 and Hela cells by using the conditioned media, indirect co-culture, and cell-to-cell co-culture. Cell growth was increased following the addition of lower proportion of hMSCs while decreased by treatment of higher proportion of hMSCs. We also established a novel noninvasive label way by using internalizing quantum dots (i-QDs) for study of cell-cell contact in the co-culture, which was effective and sensitive for both tracking and distinguishing different cells population without the disturbance of cells. Furthermore, we investigated the role of hMSCs in regulation of cell growth and showed that mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) signaling pathways were involved in hMSC-mediated cell inhibition and proliferation. Our findings suggested that hMSCs regulated cancer cell function by providing a suitable environment, and the discovery from the study would provide some clues for development of effective strategy for hMSC-based cancer therapies.

ARABIDOPSIS THALIANA HOMEOBOX GENE1 establishes the basal boundaries of shoot organs and controls stem growth.

PubMed

Gómez-Mena, Concepción; Sablowski, Robert

2008-08-01

Apical meristems play a central role in plant development. Self-renewing cells in the central region of the shoot meristem replenish the cell population in the peripheral region, where organ primordia emerge in a predictable pattern, and in the underlying rib meristem, where new stem tissue is formed. While much is known about how organ primordia are initiated and their lateral boundaries established, development at the interface between the stem and the meristem or the lateral organs is poorly understood. Here, we show that the BELL-type ARABIDOPSIS THALIANA HOMEOBOX GENE1 (ATH1) is required for proper development of the boundary between the stem and both vegetative and reproductive organs and that this role partially overlaps with that of CUP-SHAPED COTYLEDON genes. During the vegetative phase, ATH1 also functions redundantly with light-activated genes to inhibit growth of the region below the shoot meristem. Consistent with a role in inhibiting stem growth, ATH1 is downregulated at the start of inflorescence development and ectopic ATH1 expression prevents growth of the inflorescence stem by reducing cell proliferation. Thus, ATH1 modulates growth at the interface between the stem, meristem, and organ primordia and contributes to the compressed vegetative habit of Arabidopsis thaliana.

Human neuroblastoma growth inhibitory factor (h-NGIF), derived from human astrocytoma conditioned medium, has neurotrophic properties.

PubMed

Eksioglu, Y Z; Iida, J; Asai, K; Ueki, T; Nakanishi, K; Isobe, I; Yamagata, K; Kato, T

1994-05-02

Investigations on the general characteristics of human astrocytoma cell line NAC-1 revealed neuroblastoma growth inhibitory activity in conditioned medium. Neuroblastoma growth inhibitory factor (NGIF) was partially purified by Econo Q, Econo CM, and Superose 12 column chromatography. The protein is weakly basic with an estimated M(r) of 120,000, possibly having an M(r) 60,000 dimeric structure. NGIF inhibits the growth of human neuroblastoma cell lines but has no effect on morphology nor does it produce any change in the growth of human glioblastoma cell lines. Interestingly, NGIF appears to promote survival and neurite outgrowth of embryonal rat cortical neurons. These neurotrophic properties suggest a role for NGIF in the development of the nervous system.

Recent Developments in β-Cell Differentiation of Pluripotent Stem Cells Induced by Small and Large Molecules

PubMed Central

Kumar, S. Suresh; Alarfaj, Abdullah A.; Munusamy, Murugan A.; Singh, A. J. A. Ranjith; Peng, I-Chia; Priya, Sivan Padma; Hamat, Rukman Awang; Higuchi, Akon

2014-01-01

Human pluripotent stem cells, including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), hold promise as novel therapeutic tools for diabetes treatment because of their self-renewal capacity and ability to differentiate into beta (β)-cells. Small and large molecules play important roles in each stage of β-cell differentiation from both hESCs and hiPSCs. The small and large molecules that are described in this review have significantly advanced efforts to cure diabetic disease. Lately, effective protocols have been implemented to induce hESCs and human mesenchymal stem cells (hMSCs) to differentiate into functional β-cells. Several small molecules, proteins, and growth factors promote pancreatic differentiation from hESCs and hMSCs. These small molecules (e.g., cyclopamine, wortmannin, retinoic acid, and sodium butyrate) and large molecules (e.g. activin A, betacellulin, bone morphogentic protein (BMP4), epidermal growth factor (EGF), fibroblast growth factor (FGF), keratinocyte growth factor (KGF), hepatocyte growth factor (HGF), noggin, transforming growth factor (TGF-α), and WNT3A) are thought to contribute from the initial stages of definitive endoderm formation to the final stages of maturation of functional endocrine cells. We discuss the importance of such small and large molecules in uniquely optimized protocols of β-cell differentiation from stem cells. A global understanding of various small and large molecules and their functions will help to establish an efficient protocol for β-cell differentiation. PMID:25526563

A Kinome RNAi Screen in Drosophila Identifies Novel Genes Interacting with Lgl, aPKC, and Crb Cell Polarity Genes in Epithelial Tissues.

PubMed

Parsons, Linda M; Grzeschik, Nicola A; Amaratunga, Kasun; Burke, Peter; Quinn, Leonie M; Richardson, Helena E

2017-08-07

In both Drosophila melanogaster and mammalian systems, epithelial structure and underlying cell polarity are essential for proper tissue morphogenesis and organ growth. Cell polarity interfaces with multiple cellular processes that are regulated by the phosphorylation status of large protein networks. To gain insight into the molecular mechanisms that coordinate cell polarity with tissue growth, we screened a boutique collection of RNAi stocks targeting the kinome for their capacity to modify Drosophila "cell polarity" eye and wing phenotypes. Initially, we identified kinase or phosphatase genes whose depletion modified adult eye phenotypes associated with the manipulation of cell polarity complexes (via overexpression of Crb or aPKC). We next conducted a secondary screen to test whether these cell polarity modifiers altered tissue overgrowth associated with depletion of Lgl in the wing. These screens identified Hippo, Jun kinase (JNK), and Notch signaling pathways, previously linked to cell polarity regulation of tissue growth. Furthermore, novel pathways not previously connected to cell polarity regulation of tissue growth were identified, including Wingless (Wg/Wnt), Ras, and lipid/Phospho-inositol-3-kinase (PI3K) signaling pathways. Additionally, we demonstrated that the "nutrient sensing" kinases Salt Inducible Kinase 2 and 3 ( SIK2 and 3 ) are potent modifiers of cell polarity phenotypes and regulators of tissue growth. Overall, our screen has revealed novel cell polarity-interacting kinases and phosphatases that affect tissue growth, providing a platform for investigating molecular mechanisms coordinating cell polarity and tissue growth during development. Copyright © 2017 Parsons et al.

Differential requirements for activation and growth of unprimed cytotoxic and helper T lymphocytes.

PubMed

Gullberg, M; Pobor, G; Bandeira, A; Larsson, E L; Coutinho, A

1983-09-01

The requirements for activation and growth of T lymphocytes capable of mediating either cytolytic activity or help to B lymphocytes were studied in unprimed splenic T cell populations. The selectivity of expression of Lyt-2 antigens, the reactivity to soluble concanavalin A (Con A), to partially purified interleukin 2 (IL 2, T cell growth factor[s]) and to lectin-pulsed macrophages (M phi) were used in this analysis. Lectin-dependent cytotoxicity assays and a novel method that allows for the detection of all effector helper cells, regardless of their clonal specificities, were used for the functional identification of the responding T cells. The results show a marked contrast between cytolytic and helper T cells in their growth and activation requirements. Thus, while Lyt-2+ cytotoxic T lymphocyte precursors grow exponentially in IL 2 after a short pulse with soluble Con A in the absence of accessory cells, Lyt-2- helper cell precursors completely fail to proliferate under the same conditions and require the continuous presence of lectin-pulsed M phi for significant growth. Furthermore, addition of IL 2 to M phi-stimulated cultures of Lyt-2- cells has no effect. T cells which produce IL 2 have the same growth characteristics as helper cells. In both cases, effector helper functions could be expanded more than 10-fold on a per cell basis by a 5-day-culture period under those growth supporting conditions. The development of effector helper functions, however, was strongly inhibited by the presence of Lyt-2+ T cells.

Onion epidermis as a new model to study the control of growth anisotropy in higher plants.

PubMed

Suslov, Dmitry; Verbelen, Jean-Pierre; Vissenberg, Kris

2009-01-01

To elucidate the role of cellulose microfibrils in the control of growth anisotropy, a link between their net orientation, in vitro cell wall extensibility, and anisotropic cell expansion was studied during development of the adaxial epidermis of onion (Allium cepa) bulb scales using polarization confocal microscopy, creep tests, and light microscopy. During growth the net cellulose alignment across the whole thickness of the outer epidermal wall changed from transverse through random to longitudinal and back to transverse relative to the bulb axis. Cell wall extension in vitro was always higher transverse than parallel to the net cellulose alignment. The direction of growth anisotropy was perpendicular to the net microfibril orientation and changed during development from longitudinal to transverse to the bulb axis. The correlation between the degree of growth anisotropy and the net cellulose alignment was poor. Thus the net cellulose microfibril orientation across the whole thickness of the outer periclinal epidermis wall defines the direction but not the degree of growth anisotropy. Strips isolated from the epidermis in the directions perpendicular and transverse to a net cellulose orientation can be used as an extensiometric model to prove a protein involvement in the control of growth anisotropy.

Investigating chitin deacetylation and chitosan hydrolysis during vegetative growth in Magnaporthe oryzae

PubMed Central

Geoghegan, Ivey A.

2017-01-01

Summary Chitin deacetylation results in the formation of chitosan, a polymer of β1,4‐linked glucosamine. Chitosan is known to have important functions in the cell walls of a number of fungal species, but its role during hyphal growth has not yet been investigated. In this study, we have characterized the role of chitin deacetylation during vegetative hyphal growth in the filamentous phytopathogen Magnaporthe oryzae. We found that chitosan localizes to the septa and lateral cell walls of vegetative hyphae and identified 2 chitin deacetylases expressed during vegetative growth—CDA1 and CDA4. Deletion strains and fluorescent protein fusions demonstrated that CDA1 is necessary for chitin deacetylation in the septa and lateral cell walls of mature hyphae in colony interiors, whereas CDA4 deacetylates chitin in the hyphae at colony margins. However, although the Δcda1 strain was more resistant to cell wall hydrolysis, growth and pathogenic development were otherwise unaffected in the deletion strains. The role of chitosan hydrolysis was also investigated. A single gene encoding a putative chitosanase (CSN) was discovered in M. oryzae and found to be expressed during vegetative growth. However, chitosan localization, vegetative growth, and pathogenic development were unaffected in a CSN deletion strain, rendering the role of this enzyme unclear. PMID:28371146

Sustained proliferation in cancer: mechanisms and novel therapeutic targets

PubMed Central

Arzumanyan, Alla; Kulathinal, Rob J.; Blain, Stacy W.; Holcombe, Randall F.; Mahajna, Jamal; Marino, Maria; Martinez-Chantar, Maria L.; Nawroth, Roman; Sanchez-Garcia, Isidro; Sharma, Dipali; Saxena, Neeraj K.; Singh, Neetu; Vlachostergios, Panagiotis J.; Guo, Shanchun; Honoki, Kanya; Fujii, Hiromasa; Georgakilas, Alexandros G.; Amedei, Amedeo; Niccolai, Elena; Amin, Amr; Ashraf, S. Salman; Boosani, Chandra S.; Guha, Gunjan; Ciriolo, Maria Rosa; Aquilano, Katia; Chen, Sophie; Mohammed, Sulma I.; Azmi, Asfar S.; Bhakta, Dipita; Halicka, Dorota; Nowsheen, Somaira

2016-01-01

Proliferation is an important part of cancer development and progression. This is manifest by altered expression and/or activity of cell cycle related proteins. Constitutive activation of many signal transduction pathways also stimulates cell growth. Early steps in tumor development are associated with a fibrogenic response and the development of a hypoxic environment which favors the survival and proliferation of cancer stem cells. Part of the survival strategy of cancer stem cells may manifested by alterations in cell metabolism. Once tumors appear, growth and metastasis may be supported by overproduction of appropriate hormones (in hormonally dependent cancers), by promoting angiogenesis, by undergoing epithelial to mesenchymal transition, by triggering autophagy, and by taking cues from surrounding stromal cells. A number of natural compounds (e.g., curcumin, resveratrol, indole-3-carbinol, brassinin, sulforaphane, epigallocatechin-3-gallate, genistein, ellagitannins, lycopene and quercetin) have been found to inhibit one or more pathways that contribute to proliferation (e.g., hypoxia inducible factor 1, nuclear factor kappa B, phosphoinositide 3 kinase/Akt, insulin-like growth factor receptor 1, Wnt, cell cycle associated proteins, as well as androgen and estrogen receptor signaling). This data, in combination with bioinformatics analyses, will be very important for identifying signaling pathways and molecular targets that may provide early diagnostic markers and/or critical targets for the development of new drugs or drug combinations that block tumor formation and progression. PMID:25892662

Impairment of growth of gastric carcinoma by miR-133-mediated Her-2 inhibition.

PubMed

Zhang, Xiao-Tao; Zhang, Zhen; Xin, Yong-Ning; Ma, Xue-Zhen; Xuan, Shi-Ying

2015-11-01

Gastric carcinoma (GC) is a leading cause of cancer-related death in China. Dysregulation of microRNAs (miRNAs) has been shown to contribute to the development of GC, whereas the role of miR-133 in GC is unknown. Here, we analyzed the levels of miR-133 in GC tissues by reverse and quantitative transcription polymerase chain reaction (RT-qPCR). We overexpressed or inhibited miR-133 in GC cells. Cell growth was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and cell apoptosis was evaluated by fluorescence-activated cell sorting (FACS) analysis. Targeted genes were predicted by a bioinformatics algorithm and confirmed by a dual-luciferase reporter assay. We detected lower miR-133 levels in GC tissues compared with normal gastric tissue. Moreover, the low miR-133 levels were correlated with low survival rate. Overexpression of miR-133 inhibited cell growth and promoted apoptosis, while depletion of miR-133 increased cell growth and suppressed apoptosis. Moreover, the 3'-untranslated region (3'UTR) of Her-2, the epidermal growth factor receptor (EGFR) that transduces cell growth signals, appeared to be targeted by miR-133. Together, these data suggest that reduced miR-133 levels in GC tissues promote GC growth, which possibly contributes to a low survival rate of GC patients. MiR-133 may target Her-2 to suppress GC cell growth.

Transforming growth factor-beta controls T helper type 1 cell development through regulation of natural killer cell interferon-gamma.

PubMed

Laouar, Yasmina; Sutterwala, Fayyaz S; Gorelik, Leonid; Flavell, Richard A

2005-06-01

Interferon-gamma and interleukin 12 produced by the innate arm of the immune system are important regulators of T helper type 1 (T(H)1) cell development, but signals that negatively regulate their expression remain controversial. Here we show that transforming growth factor-beta (TGF-beta) controlled T(H)1 differentiation through the regulation of interferon-gamma produced by natural killer (NK) cells. Blockade of TGF-beta signaling in NK cells caused the accumulation of a large pool of NK cells secreting copious interferon-gamma, responsible for T(H)1 differentiation and protection from leishmania infection. In contrast, blockade of TGF-beta signaling in dendritic cells did not affect dendritic cell homeostasis or interleukin 12 production, thus indicating a previously undescribed demarcation of the function of TGF-beta in NK cells versus dendritic cells.

Investigating chitin deacetylation and chitosan hydrolysis during vegetative growth in Magnaporthe oryzae.

PubMed

Geoghegan, Ivey A; Gurr, Sarah J

2017-09-01

Chitin deacetylation results in the formation of chitosan, a polymer of β1,4-linked glucosamine. Chitosan is known to have important functions in the cell walls of a number of fungal species, but its role during hyphal growth has not yet been investigated. In this study, we have characterized the role of chitin deacetylation during vegetative hyphal growth in the filamentous phytopathogen Magnaporthe oryzae. We found that chitosan localizes to the septa and lateral cell walls of vegetative hyphae and identified 2 chitin deacetylases expressed during vegetative growth-CDA1 and CDA4. Deletion strains and fluorescent protein fusions demonstrated that CDA1 is necessary for chitin deacetylation in the septa and lateral cell walls of mature hyphae in colony interiors, whereas CDA4 deacetylates chitin in the hyphae at colony margins. However, although the Δcda1 strain was more resistant to cell wall hydrolysis, growth and pathogenic development were otherwise unaffected in the deletion strains. The role of chitosan hydrolysis was also investigated. A single gene encoding a putative chitosanase (CSN) was discovered in M. oryzae and found to be expressed during vegetative growth. However, chitosan localization, vegetative growth, and pathogenic development were unaffected in a CSN deletion strain, rendering the role of this enzyme unclear. © 2017 The Authors Cellular Microbiology Published by John Wiley & Sons Ltd.

Overexpression of OsEXPA8, a Root-Specific Gene, Improves Rice Growth and Root System Architecture by Facilitating Cell Extension

PubMed Central

Ma, Nana; Wang, Ying; Qiu, Shichun; Kang, Zhenhui; Che, Shugang; Wang, Guixue; Huang, Junli

2013-01-01

Expansins are unique plant cell wall proteins that are involved in cell wall modifications underlying many plant developmental processes. In this work, we investigated the possible biological role of the root-specific α-expansin gene OsEXPA8 in rice growth and development by generating transgenic plants. Overexpression of OsEXPA8 in rice plants yielded pleiotropic phenotypes of improved root system architecture (longer primary roots, more lateral roots and root hairs), increased plant height, enhanced leaf number and enlarged leaf size. Further study indicated that the average cell length in both leaf and root vascular bundles was enhanced, and the cell growth in suspension cultures was increased, which revealed the cellular basis for OsEXPA8-mediated rice plant growth acceleration. Expansins are thought to be a key factor required for cell enlargement and wall loosening. Atomic force microscopy (AFM) technology revealed that average wall stiffness values for 35S::OsEXPA8 transgenic suspension-cultured cells decreased over six-fold compared to wild-type counterparts during different growth phases. Moreover, a prominent change in the wall polymer composition of suspension cells was observed, and Fourier-transform infrared (FTIR) spectra revealed a relative increase in the ratios of the polysaccharide/lignin content in cell wall compositions of OsEXPA8 overexpressors. These results support a role for expansins in cell expansion and plant growth. PMID:24124527

Transcriptome analysis of cattle muscle identifies potential markers for skeletal muscle growth rate and major cell types.

PubMed

Guo, Bing; Greenwood, Paul L; Cafe, Linda M; Zhou, Guanghong; Zhang, Wangang; Dalrymple, Brian P

2015-03-13

This study aimed to identify markers for muscle growth rate and the different cellular contributors to cattle muscle and to link the muscle growth rate markers to specific cell types. The expression of two groups of genes in the longissimus muscle (LM) of 48 Brahman steers of similar age, significantly enriched for "cell cycle" and "ECM (extracellular matrix) organization" Gene Ontology (GO) terms was correlated with average daily gain/kg liveweight (ADG/kg) of the animals. However, expression of the same genes was only partly related to growth rate across a time course of postnatal LM development in two cattle genotypes, Piedmontese x Hereford (high muscling) and Wagyu x Hereford (high marbling). The deposition of intramuscular fat (IMF) altered the relationship between the expression of these genes and growth rate. K-means clustering across the development time course with a large set of genes (5,596) with similar expression profiles to the ECM genes was undertaken. The locations in the clusters of published markers of different cell types in muscle were identified and used to link clusters of genes to the cell type most likely to be expressing them. Overall correspondence between published cell type expression of markers and predicted major cell types of expression in cattle LM was high. However, some exceptions were identified: expression of SOX8 previously attributed to muscle satellite cells was correlated with angiogenesis. Analysis of the clusters and cell types suggested that the "cell cycle" and "ECM" signals were from the fibro/adipogenic lineage. Significant contributions to these signals from the muscle satellite cells, angiogenic cells and adipocytes themselves were not as strongly supported. Based on the clusters and cell type markers, sets of five genes predicted to be representative of fibro/adipogenic precursors (FAPs) and endothelial cells, and/or ECM remodelling and angiogenesis were identified. Gene sets and gene markers for the analysis of many of the major processes/cell populations contributing to muscle composition and growth have been proposed, enabling a consistent interpretation of gene expression datasets from cattle LM. The same gene sets are likely to be applicable in other cattle muscles and in other species.

Measurement of the volume growth rate of single budding yeast with the MOSFET-based microfluidic Coulter counter

PubMed Central

Sun, Jiashu; Stowers, Chris C.; Boczko, Erik M.

2012-01-01

We report on measurements of the volume growth rate of ten individual budding yeast cells using a recently developed MOSFET-based microfluidic Coulter counter. The MOSFET-based microfluidic Coulter counter is very sensitive, provides signals that are immune from the baseline drift, and can work with cell culture media of complex composition. These desirable features allow us to directly measure the volume growth rate of single cells of Saccharomyces cerevisiae LYH3865 strain budding yeast in YNB culture media over a whole cell cycle. Results indicate that all budding yeast follow a sigmoid volume growth profile with reduced growth rates at the initial stage before the bud emerges and the final stage after the daughter gets mature. Analysis of the data indicates that even though all piecewise linear, Gomperitz, and Hill’s function models can fit the global growth profile equally well, the data strongly support local exponential growth phenomenon. Accurate volume growth measurements are important for applications in systems biology where quantitative parameters are required for modeling and simulation. PMID:20717618

Measurement of the volume growth rate of single budding yeast with the MOSFET-based microfluidic Coulter counter.

PubMed

Sun, Jiashu; Stowers, Chris C; Boczko, Erik M; Li, Deyu

2010-11-07

We report on measurements of the volume growth rate of ten individual budding yeast cells using a recently developed MOSFET-based microfluidic Coulter counter. The MOSFET-based microfluidic Coulter counter is very sensitive, provides signals that are immune from the baseline drift, and can work with cell culture media of complex composition. These desirable features allow us to directly measure the volume growth rate of single cells of Saccharomyces cerevisiae LYH3865 strain budding yeast in YNB culture media over a whole cell cycle. Results indicate that all budding yeast follow a sigmoid volume growth profile with reduced growth rates at the initial stage before the bud emerges and the final stage after the daughter gets mature. Analysis of the data indicates that even though all piecewise linear, Gomperitz, and Hill's function models can fit the global growth profile equally well, the data strongly support local exponential growth phenomenon. Accurate volume growth measurements are important for applications in systems biology where quantitative parameters are required for modeling and simulation.

Mycobacteria Modify Their Cell Size Control under Sub-Optimal Carbon Sources

PubMed Central

Priestman, Miles; Thomas, Philipp; Robertson, Brian D.; Shahrezaei, Vahid

2017-01-01

The decision to divide is the most important one that any cell must make. Recent single cell studies suggest that most bacteria follow an “adder” model of cell size control, incorporating a fixed amount of cell wall material before dividing. Mycobacteria, including the causative agent of tuberculosis Mycobacterium tuberculosis, are known to divide asymmetrically resulting in heterogeneity in growth rate, doubling time, and other growth characteristics in daughter cells. The interplay between asymmetric cell division and adder size control has not been extensively investigated. Moreover, the impact of changes in the environment on growth rate and cell size control have not been addressed for mycobacteria. Here, we utilize time-lapse microscopy coupled with microfluidics to track live Mycobacterium smegmatis cells as they grow and divide over multiple generations, under a variety of growth conditions. We demonstrate that, under optimal conditions, M. smegmatis cells robustly follow the adder principle, with constant added length per generation independent of birth size, growth rate, and inherited pole age. However, the nature of the carbon source induces deviations from the adder model in a manner that is dependent on pole age. Understanding how mycobacteria maintain cell size homoeostasis may provide crucial targets for the development of drugs for the treatment of tuberculosis, which remains a leading cause of global mortality. PMID:28748182

Cell longevity and sustained primary growth in palm stems.

PubMed

Tomlinson, P Barry; Huggett, Brett A

2012-12-01

Longevity, or organismal life span, is determined largely by the period over which constituent cells can function metabolically. Plants, with modular organization (the ability continually to develop new organs and tissues) differ from animals, with unitary organization (a fixed body plan), and this difference is reflected in their respective life spans, potentially much longer in plants than animals. We draw attention to the observation that palm trees, as a group of monocotyledons without secondary growth comparable to that of lignophytes (plants with secondary growth from a bifacial cambium), retain by means of sustained primary growth living cells in their trunks throughout their organismal life span. Does this make palms the longest-lived trees because they can grow as individuals for several centuries? No conventional lignophyte retains living metabolically active differentiated cell types in its trunk for this length of time, even though the tree as a whole can exist for millennia. Does this contrast also imply that the long-lived cells in a palm trunk have exceptional properties, which allows this seeming immortality? We document the long-life of many tall palm species and their inherent long-lived stem cell properties, comparing such plants to conventional trees. We provide a summary of aspects of cell age and life span in animals and plants. Cell replacement is a feature of animal function, whereas conventional trees rely on active growth centers (meristems) to sustain organismal development. However, the long persistence of living cells in palm trunks is seen not as evidence for unique metabolic processes that sustain longevity, but is a consequence of unique constructional features. This conclusion suggests that the life span of plant cells is not necessarily genetically determined.

Cost-effective differentiation of hepatocyte-like cells from human pluripotent stem cells using small molecules.

PubMed

Tasnim, Farah; Phan, Derek; Toh, Yi-Chin; Yu, Hanry

2015-11-01

Significant efforts have been invested into the differentiation of stem cells into functional hepatocyte-like cells that can be used for cell therapy, disease modeling and drug screening. Most of these efforts have been concentrated on the use of growth factors to recapitulate developmental signals under in vitro conditions. Using small molecules instead of growth factors would provide an attractive alternative since small molecules are cell-permeable and cheaper than growth factors. We have developed a protocol for the differentiation of human embryonic stem cells into hepatocyte-like cells using a predominantly small molecule-based approach (SM-Hep). This 3 step differentiation strategy involves the use of optimized concentrations of LY294002 and bromo-indirubin-3'-oxime (BIO) for the generation of definitive endoderm; sodium butyrate and dimethyl sulfoxide (DMSO) for the generation of hepatoblasts and SB431542 for differentiation into hepatocyte-like cells. Activin A is the only growth factor required in this protocol. Our results showed that SM-Hep were morphologically and functionally similar or better compared to the hepatocytes derived from the growth-factor induced differentiation (GF-Hep) in terms of expression of hepatic markers, urea and albumin production and cytochrome P450 (CYP1A2 and CYP3A4) activities. Cell viability assays following treatment with paradigm hepatotoxicants Acetaminophen, Chlorpromazine, Diclofenac, Digoxin, Quinidine and Troglitazone showed that their sensitivity to these drugs was similar to human primary hepatocytes (PHHs). Using SM-Hep would result in 67% and 81% cost reduction compared to GF-Hep and PHHs respectively. Therefore, SM-Hep can serve as a robust and cost effective replacement for PHHs for drug screening and development. Copyright © 2015 Elsevier Ltd. All rights reserved.

Physiology regulates the relationship between coccosphere geometry and growth phase in coccolithophores

NASA Astrophysics Data System (ADS)

Sheward, Rosie M.; Poulton, Alex J.; Gibbs, Samantha J.; Daniels, Chris J.; Bown, Paul R.

2017-03-01

Coccolithophores are an abundant phytoplankton group that exhibit remarkable diversity in their biology, ecology and calcitic exoskeletons (coccospheres). Their extensive fossil record is a testament to their important biogeochemical role and is a valuable archive of biotic responses to environmental change stretching back over 200 million years. However, to realise the full potential of this archive for (palaeo-)biology and biogeochemistry requires an understanding of the physiological processes that underpin coccosphere architecture. Using culturing experiments on four modern coccolithophore species (Calcidiscus leptoporus, Calcidiscus quadriperforatus, Helicosphaera carteri and Coccolithus braarudii) from three long-lived families, we investigate how coccosphere architecture responds to shifts from exponential (rapid cell division) to stationary (slowed cell division) growth phases as cell physiology reacts to nutrient depletion. These experiments reveal statistical differences in coccosphere size and the number of coccoliths per cell between these two growth phases, specifically that cells in exponential-phase growth are typically smaller with fewer coccoliths, whereas cells experiencing growth-limiting nutrient depletion have larger coccosphere sizes and greater numbers of coccoliths per cell. Although the exact numbers are species-specific, these growth-phase shifts in coccosphere geometry demonstrate that the core physiological responses of cells to nutrient depletion result in increased coccosphere sizes and coccoliths per cell across four different coccolithophore families (Calcidiscaceae, Coccolithaceae, Isochrysidaceae and Helicosphaeraceae), a representative diversity of this phytoplankton group. Building on this, the direct comparison of coccosphere geometries in modern and fossil coccolithophores enables a proxy for growth phase to be developed that can be used to investigate growth responses to environmental change throughout their long evolutionary history. Our data also show that changes in growth rate and coccoliths per cell associated with growth-phase shifts can substantially alter cellular calcite production. Coccosphere geometry is therefore a valuable tool for accessing growth information in the fossil record, providing unprecedented insights into the response of species to environmental change and the potential biogeochemical consequences.

The NASA light-emitting diode medical program-progress in space flight and terrestrial applications

NASA Astrophysics Data System (ADS)

Whelan, Harry T.; Houle, John M.; Whelan, Noel T.; Donohoe, Deborah L.; Cwiklinski, Joan; Schmidt, Meic H.; Gould, Lisa; Larson, David L.; Meyer, Glenn A.; Cevenini, Vita; Stinson, Helen

2000-01-01

This work is supported and managed through the NASA Marshall Space Flight Center-SBIR Program. Studies on cells exposed to microgravity and hypergravity indicate that human cells need gravity to stimulate cell growth. As the gravitational force increases or decreases, the cell function responds in a linear fashion. This poses significant health risks for astronauts in long termspace flight. LED-technology developed for NASA plant growth experiments in space shows promise for delivering light deep into tissues of the body to promote wound healing and human tissue growth. This LED-technology is also biologically optimal for photodynamic therapy of cancer. .

Inhibition of vascular endothelial growth factor-induced angiogenesis suppresses tumour growth in vivo

NASA Astrophysics Data System (ADS)

Kim, K. Jin; Li, Bing; Winer, Jane; Armanini, Mark; Gillett, Nancy; Phillips, Heidi S.; Ferrara, Napoleone

1993-04-01

THE development of new blood vessels (angiogenesis) is required for many physiological processes including embryogenesis, wound healing and corpus luteum formation1,2. Blood vessel neoformation is also important in the pathogenesis of many disorders1-5, particularly rapid growth and metastasis of solid tumours3-5. There are several potential mediators of tumour angiogenesis, including basic and acidic fibroblast growth factors, tumour necrosis factor-α and transforming factors-α and -β 1,2. But it is unclear whether any of these agents actually mediates angiogenesis and tumour growth in vivo. Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen and an angiogenesis inducer released by a variety of tumour cells and expressed in human tumours in situ. To test whether VEGF may be a tumour angiogenesis factor in vivo, we injected human rhabdomyosar-coma, glioblastoma multiforme or leiomyosarcoma cell lines into nude mice. We report here that treatment with a monoclonal antibody specific for VEGF inhibited the growth of the tumours, but had no effect on the growth rate of the tumour cells In vitro. The density of vessels was decreased in the antibody-treated tumours. These findings demonstrate that inhibition of the action of an angiogenic factor spontaneously produced by tumour cells may suppress tumour growth in vivo.

Developmental patterning of the sub-epidermal integument cell layer in Arabidopsis seeds

PubMed Central

Coen, Olivier; Fiume, Elisa; Xu, Wenjia; De Vos, Delphine; Lu, Jing; Pechoux, Christine; Lepiniec, Loïc

2017-01-01

Angiosperm seed development is a paradigm of tissue cross-talk. Proper seed formation requires spatial and temporal coordination of the fertilization products – embryo and endosperm – and the surrounding seed coat maternal tissue. In early Arabidopsis seed development, all seed integuments were thought to respond homogenously to endosperm growth. Here, we show that the sub-epidermal integument cell layer has a unique developmental program. We characterized the cell patterning of the sub-epidermal integument cell layer, which initiates a previously uncharacterized extra cell layer, and identified TRANSPARENT TESTA 16 and SEEDSTICK MADS box transcription factors as master regulators of its polar development and cell architecture. Our data indicate that the differentiation of the sub-epidermal integument cell layer is insensitive to endosperm growth alone and to the repressive mechanism established by FERTILIZATION INDEPENDENT ENDOSPERM and MULTICOPY SUPPRESSOR OF IRA1 Polycomb group proteins. This work demonstrates the different responses of epidermal and sub-epidermal integument cell layers to fertilization. PMID:28348169

Silencing VDAC1 Expression by siRNA Inhibits Cancer Cell Proliferation and Tumor Growth In Vivo

PubMed Central

Arif, Tasleem; Vasilkovsky, Lilia; Refaely, Yael; Konson, Alexander; Shoshan-Barmatz, Varda

2014-01-01

Alterations in cellular metabolism and bioenergetics are vital for cancer cell growth and motility. Here, the role of the mitochondrial protein voltage-dependent anion channel (VDAC1), a master gatekeeper regulating the flux of metabolites and ions between mitochondria and the cytoplasm, in regulating the growth of several cancer cell lines was investigated by silencing VDAC1 expression using small interfering RNA (siRNA). A single siRNA specific to the human VDAC1 sequence at nanomolar concentrations led to some 90% decrease in VDAC1 levels in the lung A549 and H358, prostate PC-3, colon HCT116, glioblastoma U87, liver HepG2, and pancreas Panc-1 cancer cell lines. VDAC1 silencing persisted 144 hours post-transfection and resulted in profound inhibition of cell growth in cancer but not in noncancerous cells, with up to 90% inhibition being observed over 5 days that was prolonged by a second transfection. Cells expressing low VDAC1 levels showed decreased mitochondrial membrane potential and adenoside triphosphate (ATP) levels, suggesting limited metabolite exchange between mitochondria and cytosol. Moreover, cells silenced for VDAC1 expression showed decreased migration, even in the presence of the wound healing accelerator basic fibroblast growth factor (bFGF). VDAC1-siRNA inhibited cancer cell growth in a Matrigel-based assay in host nude mice. Finally, in a xenograft lung cancer mouse model, chemically modified VDAC1-siRNA not only inhibited tumor growth but also resulted in tumor regression. This study thus shows that VDAC1 silencing by means of RNA interference (RNAi) dramatically inhibits cancer cell growth and tumor development by disabling the abnormal metabolic behavior of cancer cells, potentially paving the way for a more effective pipeline of anticancer drugs. PMID:24781191

Implications of pleiotrophin in human PC3 prostate cancer cell growth in vivo.

PubMed

Tsirmoula, Sotiria; Dimas, Kostas; Hatziapostolou, Maria; Lamprou, Margarita; Ravazoula, Panagiota; Papadimitriou, Evangelia

2012-10-01

Pleiotrophin (PTN) is a heparin-binding growth factor with diverse functions related to tumor growth, angiogenesis, and metastasis. Pleiotrophin seems to have a significant role in prostate cancer cell growth and to mediate the stimulatory actions of other factors that affect prostate cancer cell functions. However, all studies carried out up to date are in vitro, using different types of human prostate cancer cell lines. The aim of the present work was to study the role of endogenous PTN in human prostate cancer growth in vivo. For this purpose, human prostate cancer PC3 cells were stably transfected with a plasmid vector, bearing the antisense PTN sequence, in order to inhibit PTN expression (AS-PC3). Migration, apoptosis, and adhesion on osteoblastic cells were measured in vitro. In vivo, PC3 cells were s.c. injected into male NOD/SCID mice, and tumor growth, survival rates, angiogenesis, apoptosis, and the number of metastasis were estimated. Pleiotrophin depletion resulted in a decreased migration capability of AS-PC3 cells compared with the corresponding mock-transfected or the non-transfected PC3 cells, as well as increased apoptosis and decreased adhesiveness to osteoblastic cells in vitro. In prostate cancer NOD/SCID mouse xenografts, PTN depletion significantly suppressed tumor growth and angiogenesis and induced apoptosis of cancer cells. In addition, PTN depletion decreased the number of metastases, providing a survival benefit for the animals bearing AS-PC3 xenografts. Our data suggest that PTN is implicated in human prostate cancer growth in vivo and could be considered a potential target for the development of new therapeutic approaches for prostate cancer. © 2012 Japanese Cancer Association.

Taste bud cell dynamics during normal and sodium-restricted development.

PubMed

Hendricks, Susan J; Brunjes, Peter C; Hill, David L

2004-04-26

Taste bud volume increases over the postnatal period to match the number of neurons providing innervation. To clarify age-related changes in fungiform taste bud volume, the current study investigated developmental changes in taste bud cell number, proliferation rate, and life span. Taste bud growth can largely be accounted for by addition of cytokeratin-19-positive taste bud cells. Examination of taste bud cell kinetics with 3H-thymidine autoradiography revealed that cell life span and turnover periods were not altered during normal development but that cells were produced more rapidly in young rats, a prominent modification that could lead to increased taste bud size. By comparison, dietary sodium restriction instituted during pre- and postnatal development results in small taste buds at adulthood as a result of fewer cytokeratin-19-positive cells. The dietary manipulation also had profound influences on taste bud growth kinetics, including an increased latency for cells to enter the taste bud and longer life span and turnover periods. These studies provide fundamental, new information about taste bud development under normal conditions and after environmental manipulations that impact nerve/target matching. Copyright 2004 Wiley-Liss, Inc.

Growth factor delivery for oral and periodontal tissue engineering

PubMed Central

Kaigler, Darnell; Cirelli, Joni A; Giannobile, William V

2008-01-01

The treatment of oral and periodontal diseases and associated anomalies accounts for a significant proportion of the healthcare burden, with the manifestations of these conditions being functionally and psychologically debilitating. Growth factors are critical to the development, maturation, maintenance and repair of craniofacial tissues, as they establish an extracellular environment that is conducive to cell and tissue growth. Tissue-engineering principles aim to exploit these properties in the development of biomimetic materials that can provide an appropriate microenvironment for tissue development. These materials have been constructed into devices that can be used as vehicles for delivery of cells, growth factors and DNA. In this review, different mechanisms of drug delivery are addressed in the context of novel approaches to reconstruct and engineer oral- and tooth-supporting structures, namely the periodontium and alveolar bone. PMID:16948560

Adenoviral modification of mouse brain derived endothelial cells, bEnd3, to induce apoptosis by vascular endothelial growth factor.

PubMed

Mitsuuchi, Y; Powell, D R; Gallo, J M

2006-02-09

A second generation genetically-engineered cell-based drug delivery system, referred to as apoptotic-induced drug delivery (AIDD), was developed using endothelial cells (ECs) that undergo apoptosis upon binding of vascular endothelial growth factor (VEGF) to a Flk-1:Fas fusion protein (FF). This new AIDD was redesigned using mouse brain derived ECs, bEnd3 cells, and an adenovirus vector in order to enhance and control the expression of FF. The FF was tagged with a HA epitope (FFHA) and designed to be coexpressed with green fluorescence protein (GFP) by the regulation of cytomegalovirus promoters in the adenovirus vector. bEnd3 cells showed favorable coexpression of FFHA and GFP consistent with the multiplicity of infection of the adenovirus. Immunofluorescence analysis demonstrated that FFHA was localized at the plasma membrane, whereas GFP was predominantly located in the cytoplasm of ECs. Cell death was induced by VEGF, but not by platelet derived growth factor or fibroblast growth factor in a dose-dependent manner (range 2-20 ng/ml), and revealed caspase-dependent apoptotic profiles. The FFHA expressing bEnd3 cells underwent apoptosis when cocultured with a glioma cell (SF188V+) line able to overexpress VEGF. The combined data indicated that the FFHA adenovirus system can induce apoptotic signaling in ECs in response to VEGF, and thus, is an instrumental modification to the development of AIDD.

Accumulation of neutral mutations in growing cell colonies with competition.

PubMed

Sorace, Ron; Komarova, Natalia L

2012-12-07

Neutral mutations play an important role in many biological processes including cancer initiation and progression, the generation of drug resistance in bacterial and viral diseases as well as cancers, and the development of organs in multicellular organisms. In this paper we study how neutral mutants are accumulated in nonlinearly growing colonies of cells subject to growth constraints such as crowding or lack of resources. We investigate different types of growth control which range from "division-controlled" to "death-controlled" growth (and various mixtures of both). In division-controlled growth, the burden of handling overcrowding lies with the process of cell-divisions, the divisions slow down as the carrying capacity is approached. In death-controlled growth, it is death rate that increases to slow down expansion. We show that division-controlled growth minimizes the number of accumulated mutations, and death-controlled growth corresponds to the maximum number of mutants. We check that these results hold in both deterministic and stochastic settings. We further develop a general (deterministic) theory of neutral mutations and achieve an analytical understanding of the mutant accumulation in colonies of a given size in the absence of back-mutations. The long-term dynamics of mutants in the presence of back-mutations is also addressed. In particular, with equal forward- and back-mutation rates, if division-controlled and a death-controlled types are competing for space and nutrients, cells obeying division-controlled growth will dominate the population. Copyright © 2012 Elsevier Ltd. All rights reserved.

Growth Mechanism of Microbial Colonies

NASA Astrophysics Data System (ADS)

Zhu, Minhui; Martini, K. Michael; Kim, Neil H.; Sherer, Nicholas; Lee, Jia Gloria; Kuhlman, Thomas; Goldenfeld, Nigel

Experiments on nutrient-limited E. coli colonies, growing on agar gel from single cells reveal a power-law distribution of sizes, both during the growth process and in the final stage when growth has ceased. We developed a Python simulation to study the growth mechanism of the bacterial population and thus understand the broad details of the experimental findings. The simulation takes into account nutrient uptake, metabolic function, growth and cell division. Bacteria are modeled in two dimensions as hard circle-capped cylinders with steric interactions and elastic stress dependent growth characteristics. Nutrient is able to diffuse within and between the colonies. The mechanism of microbial colony growth involves reproduction of cells within the colonies and the merging of different colonies. We report results on the dynamic scaling laws and final state size distribution, that capture in semi-quantitative detail the trends observed in experiment. Supported by NSF Grant 0822613.

Chlamydia trachomatis growth and development requires the activity of host Long-chain Acyl-CoA Synthetases (ACSLs)

PubMed Central

Recuero-Checa, Maria A.; Sharma, Manu; Lau, Constance; Watkins, Paul A.; Gaydos, Charlotte A.; Dean, Deborah

2016-01-01

The obligate-intracellular pathogen Chlamydia trachomatis (Ct) has undergone considerable genome reduction with consequent dependence on host biosynthetic pathways, metabolites and enzymes. Long-chain acyl-CoA synthetases (ACSLs) are key host-cell enzymes that convert fatty acids (FA) into acyl-CoA for use in metabolic pathways. Here, we show that the complete host ACSL family [ACSL1 and ACSL3–6] translocates into the Ct membrane-bound vacuole, termed inclusion, and remains associated with membranes of metabolically active forms of Ct throughout development. We discovered that three different pharmacologic inhibitors of ACSL activity independently impede Ct growth in a dose-dependent fashion. Using an FA competition assay, host ACSLs were found to activate Ct branched-chain FAs, suggesting that one function of the ACSLs is to activate Ct FAs and host FAs (recruited from the cytoplasm) within the inclusion. Because the ACSL inhibitors can deplete lipid droplets (LD), we used a cell line where LD synthesis was switched off to evaluate whether LD deficiency affects Ct growth. In these cells, we found no effect on growth or on translocation of ACSLs into the inclusion. Our findings support an essential role for ACSL activation of host-cell and bacterial FAs within the inclusion to promote Ct growth and development, independent of LDs. PMID:26988341

Chemical vapor deposition growth

NASA Technical Reports Server (NTRS)

Ruth, R. P.; Manasevit, H. M.; Campbell, A. G.; Johnson, R. E.; Kenty, J. L.; Moudy, L. A.; Shaw, G. L.; Simpson, W. I.; Yang, J. J.

1978-01-01

The objective was to investigate and develop chemical vapor deposition (CVD) techniques for the growth of large areas of Si sheet on inexpensive substrate materials, with resulting sheet properties suitable for fabricating solar cells that would meet the technical goals of the Low Cost Silicon Solar Array Project. The program involved six main technical tasks: (1) modification and test of an existing vertical-chamber CVD reactor system; (2) identification and/or development of suitable inexpensive substrate materials; (3) experimental investigation of CVD process parameters using various candidate substrate materials; (4) preparation of Si sheet samples for various special studies, including solar cell fabrication; (5) evaluation of the properties of the Si sheet material produced by the CVD process; and (6) fabrication and evaluation of experimental solar cell structures, using impurity diffusion and other standard and near-standard processing techniques supplemented late in the program by the in situ CVD growth of n(+)/p/p(+) sheet structures subsequently processed into experimental cells.

MicroRNA-138 Regulates DNA Damage Response in Small Cell Lung Cancer Cells by Directly Targeting H2AX.

PubMed

Yang, Huan; Luo, Jinwen; Liu, Zhiguang; Zhou, Rui; Luo, Hong

2015-04-01

Lung cancer is the leading cause of cancer death worldwide and small cell lung cancer (SCLC) accounts for a significant proportion of all lung cancer cases. Even so, the underlying mechanism governing SCLC development remains poorly understood and SCLC related cancer death stands high despite decades of intensive investigation. We noted that both miR-138 and H2AX have been implicated in development of various malignancies. Also, there is a recent report showing the role of miR-138 in mediating DNA damage response by targeting H2AX. In light of these data, we sought to characterize the role of miR-138 for SCLC cell growth and cell-cycle progression by regulating H2AX expression. Results showed that miR-138 is significantly down-regulated in SCLC tumor tissues as well as in three SCLC cell lines. After successfully engineering miR-138 overexpression in one of the SCLC cell lines, NCI-H2081, we observed a remarkable reduction of cell growth and a significant inhibition on cell-cycle progression. Moreover, we were able to show that miR-138 potently inhibits H2AX expression, which suggests that H2AX may serve as a downstream executor for miR-138. Consistent with this hypothesis, we found that engineered H2AX knockdown achieves a similar effect as observed for miR-138 overexpression in terms of SCLC growth and cell cycle regulation. We also showed that H2AX overexpression largely abolished miR-138-mediated SCLC cancer cell growth and cell-cycle progression inhibition, which strongly suggests, at least in vitro, that miR-138 potently regulates SCLC development by targeting H2AX. In addition, we found lower miR-138 expression confers SCLC cells with greater DNA damage repair capacity. Finally, we were able to show miR-138 overexpression inhibits DNA damage repair in SCLC cells while miR-138 knockdown further facilitates DNA damage repair in these cells after IR. To date, there has been no study showing the role of miR-138/H2AX machinery in SCLC development. Our results may shed a light to development of new lines of SCLC diagnosis and treatment approaches.

Calcium/calmodulin-dependent protein kinase II activity regulates the proliferative potential of growth plate chondrocytes.

PubMed

Li, Yuwei; Ahrens, Molly J; Wu, Amy; Liu, Jennifer; Dudley, Andrew T

2011-01-01

For tissues that develop throughout embryogenesis and into postnatal life, the generation of differentiated cells to promote tissue growth is at odds with the requirement to maintain the stem cell/progenitor cell population to preserve future growth potential. In the growth plate cartilage, this balance is achieved in part by establishing a proliferative phase that amplifies the number of progenitor cells prior to terminal differentiation into hypertrophic chondrocytes. Here, we show that endogenous calcium/calmodulin-dependent protein kinase II (CamkII, also known as Camk2) activity is upregulated prior to hypertrophy and that loss of CamkII function substantially blocks the transition from proliferation to hypertrophy. Wnt signaling and Pthrp-induced phosphatase activity negatively regulate CamkII activity. Release of this repression results in activation of multiple effector pathways, including Runx2- and β-catenin-dependent pathways. We present an integrated model for the regulation of proliferation potential by CamkII activity that has important implications for studies of growth control and adult progenitor/stem cell populations.

Molecular cloning and chromosomal mapping of bone marrow stromal cell surface gene, BST2, that may be involved in pre-B-cell growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ishikawa, Jun; Kaisho, Tsuneyasu; Tomizawa, Hitoshi

1995-04-10

Bone marrow stromal cells regulate B-cell growth and development through their surface molecules and cytokines. In this study, we generated a mAb, RS38, that recognized a novel human membrane protein, BST-2, expressed on bone marrow stromal cell lines and synovial cell lines. We cloned a cDNA encoding BST-2 from a rheumatoid arthritis-derived synovial cell line. BST-2 is a 30- to 36-kDa type II transmembrane protein, consisting of 180 amino acids. The BST-2 gene (HGMW-approved symbol BST2) is located on chromosome 19p13.2. BST-2 is expressed not only on certain bone marrow stromal cell lines but also on various normal tissues, althoughmore » its expression pattern is different from that of another bone marrow stromal cell surface molecule, BST-1. BST-2 surface expression on fibroblast cell lines facilitated the stromal cell-dependent growth of a murine bone marrow-derived pre-B-cell line, DW34. The results suggest that BST-2 may be involved in pre-B-cell growth. 45 refs., 7 figs., 2 tabs.« less

Systematic identification of genes involved in divergent skeletal muscle growth rates of broiler and layer chickens.

PubMed

Zheng, Qi; Zhang, Yong; Chen, Ying; Yang, Ning; Wang, Xiu-Jie; Zhu, Dahai

2009-02-22

The genetic closeness and divergent muscle growth rates of broilers and layers make them great models for myogenesis study. In order to discover the molecular mechanisms determining the divergent muscle growth rates and muscle mass control in different chicken lines, we systematically identified differentially expressed genes between broiler and layer skeletal muscle cells during different developmental stages by microarray hybridization experiment. Taken together, 543 differentially expressed genes were identified between broilers and layers across different developmental stages. We found that differential regulation of slow-type muscle gene expression, satellite cell proliferation and differentiation, protein degradation rate and genes in some metabolic pathways could give great contributions to the divergent muscle growth rates of the two chicken lines. Interestingly, the expression profiles of a few differentially expressed genes were positively or negatively correlated with the growth rates of broilers and layers, indicating that those genes may function in regulating muscle growth during development. The multiple muscle cell growth regulatory processes identified by our study implied that complicated molecular networks involved in the regulation of chicken muscle growth. These findings will not only offer genetic information for identifying candidate genes for chicken breeding, but also provide new clues for deciphering mechanisms underlining muscle development in vertebrates.

Recent Progress Towards Quantum Dot Solar Cells with Enhanced Optical Absorption.

PubMed

Zheng, Zerui; Ji, Haining; Yu, Peng; Wang, Zhiming

2016-12-01

Quantum dot solar cells, as a promising candidate for the next generation solar cell technology, have received tremendous attention in the last 10 years. Some recent developments in epitaxy growth and device structures have opened up new avenues for practical quantum dot solar cells. Unfortunately, the performance of quantum dot solar cells is often plagued by marginal photon absorption. In this review, we focus on the recent progress made in enhancing optical absorption in quantum dot solar cells, including optimization of quantum dot growth, improving the solar cells structure, and engineering light trapping techniques.

Quiz: Test Your Skin Cancer IQ

MedlinePlus

... three main types of skin cancer: basal cell carcinoma, squamous cell carcinoma, and melanoma. They can develop from the uncontrolled growth of three different types of skin cells: basal cells, squamous cells, and melanocytes, respectively. A is the correct answer. ...

Role of IGF1 and EFN-EPH signaling in skeletal metabolism.

PubMed

Lindsey, Richard C; Rundle, Charles H; Mohan, Subburaman

2018-07-01

Insulin-like growth factor 1(IGF1) and ephrin ligand (EFN)-receptor (EPH) signaling are both crucial for bone cell function and skeletal development and maintenance. IGF1 signaling is the major mediator of growth hormone-induced bone growth, but a host of different signals and factors regulate IGF1 signaling at the systemic and local levels. Disruption of the Igf1 gene results in reduced peak bone mass in both experimental animal models and humans. Additionally, EFN-EPH signaling is a complex system which, particularly through cell-cell interactions, contributes to the development and differentiation of many bone cell types. Recent evidence has demonstrated several ways in which the IGF1 and EFN-EPH signaling pathways interact with and depend upon each other to regulate bone cell function. While much remains to be elucidated, the interaction between these two signaling pathways opens a vast array of new opportunities for investigation into the mechanisms of and potential therapies for skeletal conditions such as osteoporosis and fracture repair. © 2018 Society for Endocrinology.

Cell distribution profiles in three-dimensional scaffolds with inverted-colloidal-crystal geometry: modeling and experimental investigations.

PubMed

Shanbhag, Sachin; Wang, Shaopeng; Kotov, Nicholas A

2005-12-01

Limited ingrowth of stromal cells is observed when a three-dimensionally ordered scaffold possessing inverted-colloidal-crystal geometry is used to culture adherent cells. In this work, a computational model explaining, as well as predicting, experimental cell distributions is developed. It incorporates a modified Contois cell-growth model that includes the effects of nutrient saturation, competitive product inhibition, and cell-contact inhibition to describe the scaffold-cell system. Our results agree with the hypothesis that the rapid growth of cells on the surface of the scaffold depletes the nutrient supply to the core, resulting in the preferential growth on the exterior of the scaffold. When the cells are cultured in a scaffold subjected to a uniform velocity field, they penetrate to a greater extent into the scaffold core. Alternative seeding and culture strategies are suggested and evaluated.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dumont, Marie; Lehner, Arnaud; Bardor, Muriel

Screening of commercially available fluoro monosaccharides as putative growth inhibitors in Arabidopsis thaliana revealed that 2-fluoro 2-l-fucose (2F-Fuc) reduces root growth at micromolar concentrations. The inability of 2F-Fuc to affect an Atfkgp mutant that is defective in the fucose salvage pathway indicates that 2F-Fuc must be converted to its cognate GDP nucleotide sugar in order to inhibit root growth. Chemical analysis of cell wall polysaccharides and glycoproteins demonstrated that fucosylation of xyloglucans and of N-linked glycans is fully inhibited by 10 μm 2F-Fuc in Arabidopsis seedling roots, but genetic evidence indicates that these alterations are not responsible for the inhibitionmore » of root development by 2F-Fuc. Inhibition of fucosylation of cell wall polysaccharides also affected pectic rhamnogalacturonan-II (RG-II). At low concentrations, 2F-Fuc induced a decrease in RG-II dimerization. Both RG-II dimerization and root growth were partially restored in 2F-Fuc-treated seedlings by addition of boric acid, suggesting that the growth phenotype caused by 2F-Fuc was due to a deficiency of RG-II dimerization. Closer investigation of the 2F-Fuc-induced growth phenotype demonstrated that cell division is not affected by 2F-Fuc treatments. In contrast, the inhibitor suppressed elongation of root cells and promoted the emergence of adventitious roots. This study further emphasizes the importance of RG-II in cell elongation and the utility of glycosyltransferase inhibitors as new tools for studying the functions of cell wall polysaccharides in plant development. Moreover, supplementation experiments with borate suggest that the function of boron in plants might not be restricted to RG-II cross-linking, but that it might also be a signal molecule in the cell wall integrity-sensing mechanism.« less

Analysis of Factors Limiting Bacterial Growth in PDMS Mother Machine Devices.

PubMed

Yang, Da; Jennings, Anna D; Borrego, Evalynn; Retterer, Scott T; Männik, Jaan

2018-01-01

The microfluidic mother machine platform has attracted much interest for its potential in studies of bacterial physiology, cellular organization, and cell mechanics. Despite numerous experiments and development of dedicated analysis software, differences in bacterial growth and morphology in narrow mother machine channels compared to typical liquid media conditions have not been systematically characterized. Here we determine changes in E. coli growth rates and cell dimensions in different sized dead-end microfluidic channels using high resolution optical microscopy. We find that E. coli adapt to the confined channel environment by becoming narrower and longer compared to the same strain grown in liquid culture. Cell dimensions decrease as the channel length increases and width decreases. These changes are accompanied by increases in doubling times in agreement with the universal growth law. In channels 100 μm and longer, cell doublings can completely stop as a result of frictional forces that oppose cell elongation. Before complete cessation of elongation, mechanical stresses lead to substantial deformation of cells and changes in their morphology. Our work shows that mechanical forces rather than nutrient limitation are the main growth limiting factor for bacterial growth in long and narrow channels.

Analysis of Factors Limiting Bacterial Growth in PDMS Mother Machine Devices

DOE PAGES

Yang, Da; Jennings, Anna D.; Borrego, Evalynn; ...

2018-05-01

The microfluidic mother machine platform has attracted much interest for its potential in studies of bacterial physiology, cellular organization, and cell mechanics. Despite numerous experiments and development of dedicated analysis software, differences in bacterial growth and morphology in narrow mother machine channels compared to typical liquid media conditions have not been systematically characterized. Here we determine changes in E. coli growth rates and cell dimensions in different sized dead-end microfluidic channels using high resolution optical microscopy. We find that E. coli adapt to the confined channel environment by becoming narrower and longer compared to the same strain grown in liquidmore » culture. Cell dimensions decrease as the channel length increases and width decreases. These changes are accompanied by increases in doubling times in agreement with the universal growth law. In channels 100 μm and longer, cell doublings can completely stop as a result of frictional forces that oppose cell elongation. Before complete cessation of elongation, mechanical stresses lead to substantial deformation of cells and changes in their morphology. Lastly, our work shows that mechanical forces rather than nutrient limitation are the main growth limiting factor for bacterial growth in long and narrow channels.« less

Analysis of Factors Limiting Bacterial Growth in PDMS Mother Machine Devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Da; Jennings, Anna D.; Borrego, Evalynn

The microfluidic mother machine platform has attracted much interest for its potential in studies of bacterial physiology, cellular organization, and cell mechanics. Despite numerous experiments and development of dedicated analysis software, differences in bacterial growth and morphology in narrow mother machine channels compared to typical liquid media conditions have not been systematically characterized. Here we determine changes in E. coli growth rates and cell dimensions in different sized dead-end microfluidic channels using high resolution optical microscopy. We find that E. coli adapt to the confined channel environment by becoming narrower and longer compared to the same strain grown in liquidmore » culture. Cell dimensions decrease as the channel length increases and width decreases. These changes are accompanied by increases in doubling times in agreement with the universal growth law. In channels 100 μm and longer, cell doublings can completely stop as a result of frictional forces that oppose cell elongation. Before complete cessation of elongation, mechanical stresses lead to substantial deformation of cells and changes in their morphology. Lastly, our work shows that mechanical forces rather than nutrient limitation are the main growth limiting factor for bacterial growth in long and narrow channels.« less

Studying molecular changes during gravity perception and response in a single cell.

PubMed

Cannon, Ashley E; Salmi, Mari L; Bushart, Thomas J; Roux, Stanley J

2015-01-01

Early studies revealed a highly predictable pattern of gravity-directed growth and development in Ceratopteris richardii spores. This makes the spores a valuable model system for the study of how a single cell senses and responds to the force of gravity. Gravity regulates both the direction and magnitude of a trans-cell calcium current in germinating spores, and the orientation of this current predicts the polarization of spore development. Molecular techniques have been developed to evaluate the transcriptomic and proteomic profiles of spores before and after gravity establishes the polarity of their development. Here we describe these techniques, along with protocols for sterilizing the spores, sowing them in a solid or liquid growth media, and evaluating germination.

Tumor-promoting desmoplasia is disrupted by depleting FAP-expressing stromal cells

PubMed Central

Scholler, John; Monslow, James; Avery, Diana; Newick, Kheng; O'Brien, Shaun; Evans, Rebecca A.; Bajor, David J.; Clendenin, Cynthia; Durham, Amy C; Buza, Elizabeth L; Vonderheide, Robert H; June, Carl H

2015-01-01

Malignant cells drive the generation of a desmoplastic and immunosuppressive tumor microenvironment. Cancer-associated stromal cells (CASCs) are a heterogeneous population that provides both negative and positive signals for tumor cell growth and metastasis. Fibroblast activation protein (FAP) is a marker of a major subset of CASCs in virtually all carcinomas. Clinically, FAP expression serves as an independent negative prognostic factor for multiple types of human malignancies. Prior studies established that depletion of FAP+ cells inhibits tumor growth by augmenting anti-tumor immunity. However, the potential for immune-independent effects on tumor growth have not been defined. Herein, we demonstrate that FAP+ CASCs are required for maintenance of the provisional tumor stroma since depletion of these cells, by adoptive transfer of FAP-targeted chimeric antigen receptor (CAR) T cells, reduced extracellular matrix proteins and glycosaminoglycans. Adoptive transfer of FAP-CAR T cells also decreased tumor vascular density and restrained growth of desmoplastic human lung cancer xenografts and syngeneic murine pancreatic cancers in an immune-independent fashion. Adoptive transfer of FAP-CAR T cells also restrained autochthonous pancreatic cancer growth. These data distinguish the function of FAP+ CASCs from other CASC subsets and provide support for further development of FAP+ stromal cell-targeted therapies for the treatment of solid tumors. PMID:25979873

Tumor-Promoting Desmoplasia Is Disrupted by Depleting FAP-Expressing Stromal Cells.

PubMed

Lo, Albert; Wang, Liang-Chuan S; Scholler, John; Monslow, James; Avery, Diana; Newick, Kheng; O'Brien, Shaun; Evans, Rebecca A; Bajor, David J; Clendenin, Cynthia; Durham, Amy C; Buza, Elizabeth L; Vonderheide, Robert H; June, Carl H; Albelda, Steven M; Puré, Ellen

2015-07-15

Malignant cells drive the generation of a desmoplastic and immunosuppressive tumor microenvironment. Cancer-associated stromal cells (CASC) are a heterogeneous population that provides both negative and positive signals for tumor cell growth and metastasis. Fibroblast activation protein (FAP) is a marker of a major subset of CASCs in virtually all carcinomas. Clinically, FAP expression serves as an independent negative prognostic factor for multiple types of human malignancies. Prior studies established that depletion of FAP(+) cells inhibits tumor growth by augmenting antitumor immunity. However, the potential for immune-independent effects on tumor growth have not been defined. Herein, we demonstrate that FAP(+) CASCs are required for maintenance of the provisional tumor stroma because depletion of these cells, by adoptive transfer of FAP-targeted chimeric antigen receptor (CAR) T cells, reduced extracellular matrix proteins and glycosaminoglycans. Adoptive transfer of FAP-CAR T cells also decreased tumor vascular density and restrained growth of desmoplastic human lung cancer xenografts and syngeneic murine pancreatic cancers in an immune-independent fashion. Adoptive transfer of FAP-CAR T cells also restrained autochthonous pancreatic cancer growth. These data distinguish the function of FAP(+) CASCs from other CASC subsets and provide support for further development of FAP(+) stromal cell-targeted therapies for the treatment of solid tumors. ©2015 American Association for Cancer Research.

Roles for insulin and ecdysteroids in differentiation of an insect cell line of epidermal origin.

PubMed

Hatt, P J; Moriniere, M; Oberlander, H; Porcheron, P

1994-10-01

During postembryonic development of insects, molting cycles affect epidermal cells with alternate periods of proliferation and differentiation. Cells of the cell line established from imaginal discs of the Indian meal moth (IAL-PID2) differentiate under the action of the molting hormone, 20-hydroxyecdysone, in a manner that is meaningful in terms of the development of the tissue from which they were derived. In particular, the hormone caused an accumulation of the cells in the G2 phase of their cycle and induced the formation of epithelial-like aggregates and the synthesis of specific proteoglycans. Recent discovery of members of the insulin superfamily in insects and the role of growth factors played by this family of molecules in vertebrates led us to check for their potential effects on IAL-PID2 cell cycle regulation. On the one hand, our results showed that insulin was involved in partial resumption of the cell cycle after an arrest caused by serum deprivation, but that other growth factors present in fetal calf serum were needed for full completion of mitosis. On the other hand, the cytostatic effect of 20-hydroxyecdysone was reversible, and, prior exposure of the cells to the hormone allowed the cells to complete one cell cycle in serum-free medium. These results suggest that the production of autocrine growth factors induced by ecdysteroids could circumvent the absence of serum. This cell culture model provides potential for further study of interactions between ecdysteroids and growth factor homologs during differentiation of insect epidermal cells.

Microarray Analyses Reveal Marked Differences in Growth Factor and Receptor Expression Between 8-Cell Human Embryos and Pluripotent Stem Cells

PubMed Central

Vlismas, Antonis; Bletsa, Ritsa; Mavrogianni, Despina; Mamali, Georgina; Pergamali, Maria; Dinopoulou, Vasiliki; Partsinevelos, George; Drakakis, Peter; Loutradis, Dimitris

2016-01-01

Previous microarray analyses of RNAs from 8-cell (8C) human embryos revealed a lack of cell cycle checkpoints and overexpression of core circadian oscillators and cell cycle drivers relative to pluripotent human stem cells [human embryonic stem cells/induced pluripotent stem (hES/iPS)] and fibroblasts, suggesting growth factor independence during early cleavage stages. To explore this possibility, we queried our combined microarray database for expression of 487 growth factors and receptors. Fifty-one gene elements were overdetected on the 8C arrays relative to hES/iPS cells, including 14 detected at least 80-fold higher, which annotated to multiple pathways: six cytokine family (CSF1R, IL2RG, IL3RA, IL4, IL17B, IL23R), four transforming growth factor beta (TGFB) family (BMP6, BMP15, GDF9, ENG), one fibroblast growth factor (FGF) family [FGF14(FH4)], one epidermal growth factor member (GAB1), plus CD36, and CLEC10A. 8C-specific gene elements were enriched (73%) for reported circadian-controlled genes in mouse tissues. High-level detection of CSF1R, ENG, IL23R, and IL3RA specifically on the 8C arrays suggests the embryo plays an active role in blocking immune rejection and is poised for trophectoderm development; robust detection of NRG1, GAB1, -2, GRB7, and FGF14(FHF4) indicates novel roles in early development in addition to their known roles in later development. Forty-four gene elements were underdetected on the 8C arrays, including 11 at least 80-fold under the pluripotent cells: two cytokines (IFITM1, TNFRSF8), five TGFBs (BMP7, LEFTY1, LEFTY2, TDGF1, TDGF3), two FGFs (FGF2, FGF receptor 1), plus ING5, and WNT6. The microarray detection patterns suggest that hES/iPS cells exhibit suppressed circadian competence, underexpression of early differentiation markers, and more robust expression of generic pluripotency genes, in keeping with an artificial state of continual uncommitted cell division. In contrast, gene expression patterns of the 8C embryo suggest that it is an independent circadian rhythm-competent equivalence group poised to signal its environment, defend against maternal immune rejection, and begin the rapid commitment events of early embryogenesis. PMID:26493868

Lack of effect of a granulocyte proliferation inhibitor or their committed precursor cells.

PubMed

Lord, B I; Testa, N G; Wright, E G; Banerjee, R K

1977-05-01

Using the agar culture technique, we have measured the effect of granulocyte extracts GCE (and of erythrocyte-RCE and lymph node extracts-LNE) on the growth and proliferation of the committed granulocytic precursor cells, CFU-C. In addition we have determined their effects on the proliferation of the developing colony cells and on the ultimate cell production in the colonies. The results show that GCE has no effect on the growth or proliferative activity on the CFU-C. It does, however, reduce both the autoradiographic labelling indices of the developing colony cells and the net colony cellularities, acting as a cell cycle modulator. These are effects specific to the GCE since at the dose levels used, neither RCE nor LNE affected these measurements.

Evaluation of a human neurite growth assay as specific screen for developmental neurotoxicants.

PubMed

Krug, Anne K; Balmer, Nina V; Matt, Florian; Schönenberger, Felix; Merhof, Dorit; Leist, Marcel

2013-12-01

Organ-specific in vitro toxicity assays are often highly sensitive, but they lack specificity. We evaluated here examples of assay features that can affect test specificity, and some general procedures are suggested on how positive hits in complex biological assays may be defined. Differentiating human LUHMES cells were used as potential model for developmental neurotoxicity testing. Forty candidate toxicants were screened, and several hits were obtained and confirmed. Although the cells had a definitive neuronal phenotype, the use of a general cell death endpoint in these cultures did not allow specific identification of neurotoxicants. As alternative approach, neurite growth was measured as an organ-specific functional endpoint. We found that neurite extension of developing LUHMES was specifically inhibited by diverse compounds such as colchicine, vincristine, narciclasine, rotenone, cycloheximide, or diquat. These compounds reduced neurite growth at concentrations that did not compromise cell viability, and neurite growth was affected more potently than the integrity of developed neurites of mature neurons. A ratio of the EC50 values of neurite growth inhibition and cell death of >4 provided a robust classifier for compounds associated with a developmental neurotoxic hazard. Screening of unspecific toxicants in the test system always yielded ratios <4. The assay identified also compounds that accelerated neurite growth, such as the rho kinase pathway modifiers blebbistatin or thiazovivin. The negative effects of colchicine or rotenone were completely inhibited by a rho kinase inhibitor. In summary, we suggest that assays using functional endpoints (neurite growth) can specifically identify and characterize (developmental) neurotoxicants.

Mathematical modeling of solid cancer growth with angiogenesis

PubMed Central

2012-01-01

Background Cancer arises when within a single cell multiple malfunctions of control systems occur, which are, broadly, the system that promote cell growth and the system that protect against erratic growth. Additional systems within the cell must be corrupted so that a cancer cell, to form a mass of any real size, produces substances that promote the growth of new blood vessels. Multiple mutations are required before a normal cell can become a cancer cell by corruption of multiple growth-promoting systems. Methods We develop a simple mathematical model to describe the solid cancer growth dynamics inducing angiogenesis in the absence of cancer controlling mechanisms. Results The initial conditions supplied to the dynamical system consist of a perturbation in form of pulse: The origin of cancer cells from normal cells of an organ of human body. Thresholds of interacting parameters were obtained from the steady states analysis. The existence of two equilibrium points determine the strong dependency of dynamical trajectories on the initial conditions. The thresholds can be used to control cancer. Conclusions Cancer can be settled in an organ if the following combination matches: better fitness of cancer cells, decrease in the efficiency of the repairing systems, increase in the capacity of sprouting from existing vascularization, and higher capacity of mounting up new vascularization. However, we show that cancer is rarely induced in organs (or tissues) displaying an efficient (numerically and functionally) reparative or regenerative mechanism. PMID:22300422

Modeling triple-negative breast cancer heterogeneity: effects of stromal macrophages, fibroblasts and tumor vasculature.

PubMed

Norton, Kerri-Ann; Jin, Kideok; Popel, Aleksander S

2018-05-08

A hallmark of breast tumors is its spatial heterogeneity that includes its distribution of cancer stem cells and progenitor cells, but also heterogeneity in the tumor microenvironment. In this study we focus on the contributions of stromal cells, specifically macrophages, fibroblasts, and endothelial cells on tumor progression. We develop a computational model of triple-negative breast cancer based on our previous work and expand it to include macrophage infiltration, fibroblasts, and angiogenesis. In vitro studies have shown that the secretomes of tumor-educated macrophages and fibroblasts increase both the migration and proliferation rates of triple-negative breast cancer cells. In vivo studies also demonstrated that blocking signaling of selected secreted factors inhibits tumor growth and metastasis in mouse xenograft models. We investigate the influences of increased migration and proliferation rates on tumor growth, the effect of the presence on fibroblasts or macrophages on growth and morphology, and the contributions of macrophage infiltration on tumor growth. We find that while the presence of macrophages increases overall tumor growth, the increase in macrophage infiltration does not substantially increase tumor growth and can even stifle tumor growth at excessive rates. Copyright © 2018. Published by Elsevier Ltd.

PCOTH, a novel gene overexpressed in prostate cancers, promotes prostate cancer cell growth through phosphorylation of oncoprotein TAF-Ibeta/SET.

PubMed

Anazawa, Yoshio; Nakagawa, Hidewaki; Furihara, Mutsuo; Ashida, Shingo; Tamura, Kenji; Yoshioka, Hiroki; Shuin, Taro; Fujioka, Tomoaki; Katagiri, Toyomasa; Nakamura, Yusuke

2005-06-01

Through genome-wide cDNA microarray analysis coupled with microdissection of prostate cancer cells, we identified a novel gene, prostate collagen triple helix (PCOTH), showing overexpression in prostate cancer cells and its precursor cells, prostatic intraepithelial neoplasia (PIN). Immunohistochemical analysis using polyclonal anti-PCOTH antibody confirmed elevated expression of PCOTH, a 100-amino-acid protein containing collagen triple-helix repeats, in prostate cancer cells and PINs. Knocking down PCOTH expression by small interfering RNA (siRNA) resulted in drastic attenuation of prostate cancer cell growth, and concordantly, LNCaP derivative cells that were designed to constitutively express exogenous PCOTH showed higher growth rate than LNCaP cells transfected with mock vector, suggesting the growth-promoting effect of PCOTH on prostate cancer cell. To investigate the biological mechanisms of this growth-promoting effect, we applied two-dimensional differential gel electrophoresis (2D-DIGE) to analyze the phospho-protein fractions in LNCaP cells transfected with PCOTH. We found that the phosphorylation level of oncoprotein TAF-Ibeta/SET was significantly elevated in LNCaP cells transfected with PCOTH than control LNCaP cells, and these findings were confirmed by Western blotting and in-gel kinase assay. Furthermore, knockdown of endogenous TAF-Ibeta expression by siRNA also attenuated viability of prostate cancer cells as well. These findings suggest that PCOTH is involved in growth and survival of prostate cancer cells thorough, in parts, the TAF-Ibeta pathway, and that this molecule should be a promising target for development of new therapeutic strategies for prostate cancers.

A novel anticancer agent SNG1153 inhibits growth of lung cancer stem/progenitor cells

PubMed Central

Wang, Jing; Zhu, Hai; Han, Yuqing; Jin, Mingji; Wang, Jun; Zhou, Congya; Ma, Junfeng; Lin, Qingcong; Wang, Zhaoyi; Meng, Kun; Fu, Xueqi

2016-01-01

Lung cancer is the leading cause of cancer-related death in both men and women. Lung cancer contains a small population of cancer cells with stem-like features known as cancer stem cells (CSCs). CSCs are often more resistant to current therapeutic treatments. Thus, it is urgent to develop a novel agent that is able to inhibit CSCs growth. In this study, we examined the ability of SNG1153, a novel chemical agent to inhibit the growth of lung CSCs. We found that SNG1153 inhibited growth and induced apoptosis in established lung cancer cells. We also found that SNG1153 inhibited the tumorsphere formation and decreased CD133-positive (lung CSC marker) cancer cells. SNG1153 was able to attenuate tumor formation in NOD/SCID (non-obese diabetic/severe combined immunodeficient) mice injected with lung tumorsphere cells. We further demonstrated that SNG1153 induced β-catenin phosphorylation and down-regulated β-catenin. Our results thus demonstrate that SNG1153 effectively inhibits the growth of lung CSCs and suggest that SNG1153 may be a novel therapeutic agent to treat human lung cancer. PMID:27281614

Cullin-4 regulates Wingless and JNK signaling-mediated cell death in the Drosophila eye

PubMed Central

Tare, Meghana; Sarkar, Ankita; Bedi, Shimpi; Kango-Singh, Madhuri; Singh, Amit

2016-01-01

In all multicellular organisms, the fundamental processes of cell proliferation and cell death are crucial for growth regulation during organogenesis. Strict regulation of cell death is important to maintain tissue homeostasis by affecting processes like regulation of cell number, and elimination of unwanted/unfit cells. The developing Drosophila eye is a versatile model to study patterning and growth, where complex signaling pathways regulate growth and cell survival. However, the molecular mechanisms underlying regulation of these processes is not fully understood. In a gain-of-function screen, we found that misexpression of cullin-4 (cul-4), an ubiquitin ligase, can rescue reduced eye mutant phenotypes. Previously, cul-4 has been shown to regulate chromatin remodeling, cell cycle and cell division. Genetic characterization of cul-4 in the developing eye revealed that loss-of-function of cul-4 exhibits a reduced eye phenotype. Analysis of twin-spots showed that in comparison with their wild-type counterparts, the cul-4 loss-of-function clones fail to survive. Here we show that cul-4 clones are eliminated by induction of cell death due to activation of caspases. Aberrant activation of signaling pathways is known to trigger cell death in the developing eye. We found that Wingless (Wg) and c-Jun-amino-terminal-(NH2)-Kinase (JNK) signaling are ectopically induced in cul-4 mutant clones, and these signals co-localize with the dying cells. Modulating levels of Wg and JNK signaling by using agonists and antagonists of these pathways demonstrated that activation of Wg and JNK signaling enhances cul-4 mutant phenotype, whereas downregulation of Wg and JNK signaling rescues the cul-4 mutant phenotypes of reduced eye. Here we present evidences to demonstrate that cul-4 is involved in restricting Wg signaling and downregulation of JNK signaling-mediated cell death during early eye development. Overall, our studies provide insights into a novel role of cul-4 in promoting cell survival in the developing Drosophila eye. PMID:28032862

Chromatin reorganisation in Epstein-Barr virus-infected cells and its role in cancer development.

PubMed

West, Michelle J

2017-10-01

The oncogenic Epstein-Barr virus (EBV) growth transforms B cells and drives lymphoma and carcinoma development. The virus encodes four key transcription factors (EBNA2, EBNA3A, EBNA3B and EBNA3C) that hijack host cell factors to bind gene control elements and reprogramme infected B cells. These viral factors predominantly target long-range enhancers to alter the expression of host cell genes that control B cell growth and survival and facilitate virus persistence. Enhancer and super-enhancer binding by these EBNAs results in large-scale reorganisation of three-dimensional enhancer-promoter architecture to drive the overexpression of oncogenes, the silencing of tumour suppressors and the modulation of transcription, cell-cycle progression, migration and adhesion. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Cloning of B cell-specific membrane tetraspanning molecule BTS possessing B cell proliferation-inhibitory function.

PubMed

Suenaga, Tadahiro; Arase, Hisashi; Yamasaki, Sho; Kohno, Masayuki; Yokosuka, Tadashi; Takeuchi, Arata; Hattori, Takamichi; Saito, Takashi

2007-11-01

Lymphocyte proliferation is regulated by signals through antigen receptors, co-stimulatory receptors, and other positive and negative modulators. Several membrane tetraspanning molecules are also involved in the regulation of lymphocyte growth and death. We cloned a new B cell-specific tetraspanning (BTS) membrane molecule, which is similar to CD20 in terms of expression, structure and function. BTS is specifically expressed in the B cell line and its expression is increased after the pre-B cell stage. BTS is expressed in intracellular granules and on the cell surface. Overexpression of BTS in immature B cell lines induces growth retardation through inhibition of cell cycle progression and cell size increase without inducing apoptosis. This inhibitory function is mediated predominantly by the N terminus of BTS. The development of mature B cells is inhibited in transgenic mice expressing BTS, suggesting that BTS is involved in the in vivo regulation of B cells. These results indicate that BTS plays a role in the regulation of cell division and B cell growth.

Activation of GPR30 inhibits growth of prostate cancer cells via sustained activation of Erk1/2, c-jun/c-fos-dependent upregulation of p21, and induction of G2 cell-cycle arrest

PubMed Central

Chan, Queeny K.Y.; Lam, Hung-Ming; Ng, Chi-Fai; Lee, Amy Y.Y.; Chan, Eddie S.Y.; Ng, Ho-Keung; Ho, Shuk-Mei; Lau, Kin-Mang

2010-01-01

G protein–coupled receptor 30 (GPR30) exhibits estrogen-binding affinity and mediates nongenomic signaling of estrogen to regulate cell growth. We here demonstrated for the first time, in contrast to the reported promoting action of GPR30 on the growth of breast and ovarian cancer cells, that activation of GPR30 by the receptor-specific, non-estrogenic ligand G-1 inhibited growth of androgen-dependent and -independent prostate cancer (PCa) cells in vitro and PC-3 xenografts in vivo. However, G-1 elicited no growth or histological changes in the prostates of intact mice and did not inhibit growth in quiescent BPH-1, an immortalized benign prostatic epithelial cell line. Treatment of PC-3 cells with G-1-induced cell-cycle arrest at the G2 phase and reduced the expression of G2-checkpoint regulators (cyclin A2, cyclin B1, cdc25c, and cdc2) and the phosphorylation of their common transcriptional regulator NF-YA in PC-3 cells. With the extensive use of siRNA knockdown experiments and the MEK inhibitor PD98059 in the present study, we dissected the mechanism underlying G-1–induced inhibition of PC-3 cell growth, which was mediated through GPR30, followed by a sustained activation of Erk1/2 and a c-jun/c-fos-dependent upregulation of p21, resulting in the arrest of PC-3 growth at the G2 phase. The discovery of this signaling pathway lays the foundation for future development of GPR30-based therapies for PCa. PMID:20203690

Norrin mediates neuroprotective effects on retinal ganglion cells via activation of the Wnt/beta-catenin signaling pathway and the induction of neuroprotective growth factors in Muller cells.

PubMed

Seitz, Roswitha; Hackl, Simon; Seibuchner, Thomas; Tamm, Ernst R; Ohlmann, Andreas

2010-04-28

Norrin is a secreted protein that binds to frizzled 4 and controls development of capillaries in retina and inner ear. We provide evidence that Norrin has distinct neuroprotective properties that are independent from its effects on vascular development. The function of Norrin was investigated in a mouse model of excitotoxic retinal ganglion cell (RGC) damage after intravitreal injection of NMDA, and in cultured Müller glia or immortalized RGC-5 cells. Intravitreal injection of Norrin significantly increased the number of surviving RGC axons in the optic nerve and decreased apoptotic death of retinal neurons following NMDA-mediated damage. This effect could be blocked by adding dickkopf (DKK)-1, an inhibitor of the Wnt/beta-catenin signaling pathway. Treatment of eyes with combined Norrin/NMDA activated Wnt/beta-catenin signaling and increased the retinal expression of leukemia inhibitory factor and endothelin-2, as well as that of neurotrophic growth factors such as fibroblast growth factor-2, brain-derived neurotrophic factor, lens epithelium-derived growth factor, and ciliary neurotrophic factor. A similar activation of Wnt/beta-catenin signaling and an increased expression of neurotrophic factors was observed in cultured Müller cells after treatment with Norrin, effects that again could be blocked by adding DKK-1. In addition, conditioned cell culture medium of Norrin-treated Müller cells increased survival of differentiated RGC-5 cells. We conclude that Norrin has pronounced neuroprotective properties on retinal neurons with the distinct potential to decrease the damaging effects of NMDA-induced RGC loss. The effects of Norrin involve activation of Wnt/beta-catenin signaling and subsequent induction of neurotrophic growth factors in Müller cells.

Characterization of phospate permease in Fusarium oxysporum f. sp vasinfectum growth, virulence and secondary metabolism

USDA-ARS?s Scientific Manuscript database

Microbial development depends on the effective sensing of environmental signals and appropriate acquisition of nutrients and other molecules critical for the organism’s growth. Levels of nutrients and other molecules within the cell, and those outside of the cell, are usually relayed to the nucleus...

Up-regulation of cyclooxygenase-2 by product-prostaglandin E2

NASA Technical Reports Server (NTRS)

Tjandrawinata, R. R.; Hughes-Fulford, M.

1997-01-01

The development of prostate cancer has been linked to high level of dietary fat intake. Our laboratory investigates the connection between cancer cell growth and fatty acid products. Studying human prostatic carcinoma PC-3 cells, we found that prostaglandin E2 (PGE2) increased cell growth and up-regulated the gene expression of its own synthesizing enzyme, cyclooxygenase-2 (COX-2). PGE2 increased COX-2 mRNA expression dose-dependently with the highest levels of stimulation seen at the 3-hour period following PGE2 addition. The NSAID flurbiprofen (5 microM), in the presence of exogenous PGE2, inhibited the up-regulation of COX-2 mRNA and cell growth. These data suggest that the levels of local intracellular PGE2 play a major role in the growth of prostate cancer cells through an activation of COX-2 gene expression.

Arabidopsis Reduces Growth Under Osmotic Stress by Decreasing SPEECHLESS Protein

PubMed Central

Kumari, Archana; Jewaria, Pawan K.; Bergmann, Dominique C.; Kakimoto, Tatsuo

2014-01-01

Plants, which are sessile unlike most animals, have evolved a system to reduce growth under stress; however, the molecular mechanisms of this stress response are not well known. During programmed development, a fraction of the leaf epidermal precursor cells become meristemoid mother cells (MMCs), which are stem cells that produce both stomatal guard cells and epidermal pavement cells. Here we report that Arabidopsis plants, in response to osmotic stress, post-transcriptionally decrease the protein level of SPEECHLESS, the transcription factor promoting MMC identity, through the action of a mitogen-activated protein kinase (MAPK) cascade. The growth reduction under osmotic stress was lessened by inhibition of the MAPK cascade or by a mutation that disrupted the MAPK target amino acids in SPEECHLESS, indicating that Arabidopsis reduces growth under stress by integrating the osmotic stress signal into the MAPK–SPEECHLESS core developmental pathway. PMID:25381317

Three-Dimensional Spatiotemporal Modeling of Colon Cancer Organoids Reveals that Multimodal Control of Stem Cell Self-Renewal is a Critical Determinant of Size and Shape in Early Stages of Tumor Growth.

PubMed

Yan, Huaming; Konstorum, Anna; Lowengrub, John S

2018-05-01

We develop a three-dimensional multispecies mathematical model to simulate the growth of colon cancer organoids containing stem, progenitor and terminally differentiated cells, as a model of early (prevascular) tumor growth. Stem cells (SCs) secrete short-range self-renewal promoters (e.g., Wnt) and their long-range inhibitors (e.g., Dkk) and proliferate slowly. Committed progenitor (CP) cells proliferate more rapidly and differentiate to produce post-mitotic terminally differentiated cells that release differentiation promoters, forming negative feedback loops on SC and CP self-renewal. We demonstrate that SCs play a central role in normal and cancer colon organoids. Spatial patterning of the SC self-renewal promoter gives rise to SC clusters, which mimic stem cell niches, around the organoid surface, and drive the development of invasive fingers. We also study the effects of externally applied signaling factors. Applying bone morphogenic proteins, which inhibit SC and CP self-renewal, reduces invasiveness and organoid size. Applying hepatocyte growth factor, which enhances SC self-renewal, produces larger sizes and enhances finger development at low concentrations but suppresses fingers at high concentrations. These results are consistent with recent experiments on colon organoids. Because many cancers are hierarchically organized and are subject to feedback regulation similar to that in normal tissues, our results suggest that in cancer, control of cancer stem cell self-renewal should influence the size and shape in similar ways, thereby opening the door to novel therapies.

Three-Dimensional Spatiotemporal Modeling of Colon Cancer Organoids Reveals that Multimodal Control of Stem Cell Self-Renewal is a Critical Determinant of Size and Shape in Early Stages of Tumor Growth

PubMed Central

Yan, Huaming; Konstorum, Anna

2017-01-01

We develop a three-dimensional multispecies mathematical model to simulate the growth of colon cancer organoids containing stem, progenitor and terminally differentiated cells, as a model of early (prevascular) tumor growth. Stem cells (SCs) secrete short-range self-renewal promoters (e.g., Wnt) and their long-range inhibitors (e.g., Dkk) and proliferate slowly. Committed progenitor (CP) cells proliferate more rapidly and differentiate to produce post-mitotic terminally differentiated cells that release differentiation promoters, forming negative feedback loops on SC and CP self-renewal. We demonstrate that SCs play a central role in normal and cancer colon organoids. Spatial patterning of the SC self-renewal promoter gives rise to SC clusters, which mimic stem cell niches, around the organoid surface, and drive the development of invasive fingers. We also study the effects of externally applied signaling factors. Applying bone morphogenic proteins, which inhibit SC and CP self-renewal, reduces invasiveness and organoid size. Applying hepatocyte growth factor, which enhances SC self-renewal, produces larger sizes and enhances finger development at low concentrations but suppresses fingers at high concentrations. These results are consistent with recent experiments on colon organoids. Because many cancers are hierarchically organized and are subject to feedback regulation similar to that in normal tissues, our results suggest that in cancer, control of cancer stem cell self-renewal should influence the size and shape in similar ways, thereby opening the door to novel therapies. PMID:28681151

Plant Growth Biophysics: the Basis for Growth Asymmetry Induced by Gravity

NASA Technical Reports Server (NTRS)

Cosgrove, D.

1985-01-01

The identification and quantification of the physical properties altered by gravity when plant stems grow upward was studied. Growth of the stem in vertical and horizontal positions was recorded by time lapse photography. A computer program that uses a cubic spline fitting algorithm was used to calculate the growth rate and curvature of the stem as a function of time. Plant stems were tested to ascertain whether cell osmotic pressure was altered by gravity. A technique for measuring the yielding properties of the cell wall was developed.

Comparison of Chlamydia trachomatis serovar L2 growth in polarized genital epithelial cells grown in three-dimensional culture with non-polarized cells.

PubMed

Dessus-Babus, Sophie; Moore, Cheryl G; Whittimore, Judy D; Wyrick, Priscilla B

2008-04-01

A common model for studying Chlamydia trachomatis and growing chlamydial stocks uses Lymphogranuloma venereum serovar L2 and non-polarized HeLa cells. However, recent publications indicate that the growth rate and progeny yields can vary considerably for a particular strain depending on the cell line/type used, and seem to be partially related to cell tropism. In the present study, the growth of invasive serovar L2 was compared in endometrial HEC-1B and endocervical HeLa cells polarized on collagen-coated microcarrier beads, as well as in HeLa cells grown in tissue culture flasks. Microscopy analysis revealed no difference in chlamydial attachment/entry patterns or in inclusion development throughout the developmental cycle between cell lines. Very comparable growth curves in both cell lines were also found using real-time PCR analysis, with increases in chlamydial DNA content of 400-500-fold between 2 and 36 h post-inoculation. Similar progeny yields with comparable infectivity were recovered from HEC-1B and HeLa cell bead cultures, and no difference in chlamydial growth was found in polarized vs. non-polarized HeLa cells. In conclusion, unlike other C. trachomatis strains such as urogenital serovar E, invasive serovar L2 grows equally well in physiologically different endometrial and endocervical environments, regardless of the host cell polarization state.

A Model of the Spatio-temporal Dynamics of Drosophila Eye Disc Development.

PubMed

Fried, Patrick; Sánchez-Aragón, Máximo; Aguilar-Hidalgo, Daniel; Lehtinen, Birgitta; Casares, Fernando; Iber, Dagmar

2016-09-01

Patterning and growth are linked during early development and have to be tightly controlled to result in a functional tissue or organ. During the development of the Drosophila eye, this linkage is particularly clear: the growth of the eye primordium mainly results from proliferating cells ahead of the morphogenetic furrow (MF), a moving signaling wave that sweeps across the tissue from the posterior to the anterior side, that induces proliferating cells anterior to it to differentiate and become cell cycle quiescent in its wake. Therefore, final eye disc size depends on the proliferation rate of undifferentiated cells and on the speed with which the MF sweeps across the eye disc. We developed a spatio-temporal model of the growing eye disc based on the regulatory interactions controlled by the signals Decapentaplegic (Dpp), Hedgehog (Hh) and the transcription factor Homothorax (Hth) and explored how the signaling patterns affect the movement of the MF and impact on eye disc growth. We used published and new quantitative data to parameterize the model. In particular, two crucial parameter values, the degradation rate of Hth and the diffusion coefficient of Hh, were measured. The model is able to reproduce the linear movement of the MF and the termination of growth of the primordium. We further show that the model can explain several mutant phenotypes, but fails to reproduce the previously observed scaling of the Dpp gradient in the anterior compartment.

Cartilage Engineering from Mesenchymal Stem Cells

NASA Astrophysics Data System (ADS)

Goepfert, C.; Slobodianski, A.; Schilling, A. F.; Adamietz, P.; Pörtner, R.

Mesenchymal progenitor cells known as multipotent mesenchymal stromal cells or mesenchymal stem cells (MSC) have been isolated from various tissues. Since they are able to differentiate along the mesenchymal lineages of cartilage and bone, they are regarded as promising sources for the treatment of skeletal defects. Tissue regeneration in the adult organism and in vitro engineering of tissues is hypothesized to follow the principles of embryogenesis. The embryonic development of the skeleton has been studied extensively with respect to the regulatory mechanisms governing morphogenesis, differentiation, and tissue formation. Various concepts have been designed for engineering tissues in vitro based on these developmental principles, most of them involving regulatory molecules such as growth factors or cytokines known to be the key regulators in developmental processes. Growth factors most commonly used for in vitro cultivation of cartilage tissue belong to the fibroblast growth factor (FGF) family, the transforming growth factor-beta (TGF-β) super-family, and the insulin-like growth factor (IGF) family. In this chapter, in vivo actions of members of these growth factors described in the literature are compared with in vitro concepts of cartilage engineering making use of these growth factors.

Inhibition of fucosylation of cell wall components by 2-fluoro 2-deoxy-L-fucose induces defects in root cell elongation.

PubMed

Dumont, Marie; Lehner, Arnaud; Bardor, Muriel; Burel, Carole; Vauzeilles, Boris; Lerouxel, Olivier; Anderson, Charles T; Mollet, Jean-Claude; Lerouge, Patrice

2015-12-01

Screening of commercially available fluoro monosaccharides as putative growth inhibitors in Arabidopsis thaliana revealed that 2-fluoro 2-l-fucose (2F-Fuc) reduces root growth at micromolar concentrations. The inability of 2F-Fuc to affect an Atfkgp mutant that is defective in the fucose salvage pathway indicates that 2F-Fuc must be converted to its cognate GDP nucleotide sugar in order to inhibit root growth. Chemical analysis of cell wall polysaccharides and glycoproteins demonstrated that fucosylation of xyloglucans and of N-linked glycans is fully inhibited by 10 μm 2F-Fuc in Arabidopsis seedling roots, but genetic evidence indicates that these alterations are not responsible for the inhibition of root development by 2F-Fuc. Inhibition of fucosylation of cell wall polysaccharides also affected pectic rhamnogalacturonan-II (RG-II). At low concentrations, 2F-Fuc induced a decrease in RG-II dimerization. Both RG-II dimerization and root growth were partially restored in 2F-Fuc-treated seedlings by addition of boric acid, suggesting that the growth phenotype caused by 2F-Fuc was due to a deficiency of RG-II dimerization. Closer investigation of the 2F-Fuc-induced growth phenotype demonstrated that cell division is not affected by 2F-Fuc treatments. In contrast, the inhibitor suppressed elongation of root cells and promoted the emergence of adventitious roots. This study further emphasizes the importance of RG-II in cell elongation and the utility of glycosyltransferase inhibitors as new tools for studying the functions of cell wall polysaccharides in plant development. Moreover, supplementation experiments with borate suggest that the function of boron in plants might not be restricted to RG-II cross-linking, but that it might also be a signal molecule in the cell wall integrity-sensing mechanism. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Pericytes and endothelial precursor cells: cellular interactions and contributions to malignancy.

PubMed

Bagley, Rebecca G; Weber, William; Rouleau, Cecile; Teicher, Beverly A

2005-11-01

Tumor vasculature is irregular, abnormal, and essential for tumor growth. Pericytes and endothelial precursor cells (EPC) contribute to the formation of blood vessels under angiogenic conditions. As primary cells in culture, pericytes and EPC share many properties such as tube/network formation and response to kinase inhibitors selective for angiogenic pathways. Expression of cell surface proteins including platelet-derived growth factor receptor, vascular cell adhesion molecule, intercellular adhesion molecule, CD105, desmin, and neural growth proteoglycan 2 was similar between pericytes and EPC, whereas expression of P1H12 and lymphocyte function-associated antigen-1 clearly differentiates the cell types. Further distinction was observed in the molecular profiles for expression of angiogenic genes. Pericytes or EPC enhanced the invasion of MDA-MB-231 breast cancer cells in a coculture assay system. The s.c. coinjection of live pericytes or EPC along with MDA-MB-231 cells resulted in an increased rate of tumor growth compared with coinjection of irradiated pericytes or EPC. Microvessel density analysis indicated there was no difference in MDA-MB-231 tumors with or without EPC or pericytes. However, immunohistochemical staining of vasculature suggested that EPC and pericytes may stabilize or normalize vasculature rather than initiate vasculogenesis. In addition, tumors arising from the coinjection of EPC and cancer cells were more likely to develop lymphatic vessels. These results support the notion that pericytes and EPC contribute to malignancy and that these cell types can be useful as cell-based models for tumor vascular development and selection of agents that may provide therapeutic benefit.

MicroRNA-100 regulates pancreatic cancer cells growth and sensitivity to chemotherapy through targeting FGFR3.

PubMed

Li, Zhipeng; Li, Xu; Yu, Chao; Wang, Min; Peng, Feng; Xiao, Jie; Tian, Rui; Jiang, Jianxin; Sun, Chengyi

2014-12-01

We intended to investigate the role of microRNA 100 (miR-100) in regulating pancreatic cancer cells' growth in vitro and tumor development in vivo. QTR-PCR was used to examine the expression of miR-100 in pancreatic cancer cell lines and tumor cells from human patients. Lentivirual vector containing miR-100 mimics (lv-miR-100) was used to overexpress miR-100 in MIA PaCa-2 and FCPAC-1 cells. The effects of overexpressing miR-100 on pancreatic cancer cell proliferation and chemosensitivity to cisplatin were examined by cell proliferation essay in vitro. MIA PaCa-2 cells with endogenously overexpressed miR-100 were transplanted into null mice to examine tumor growth in vivo. The predicted target of miR-100, fibroblast growth factor receptor 3 (FGFR3), was downregulated by siRNA to examine its effect on pancreatic cancer cells. We found miR-100 was markedly underexpressed in both pancreatic cancer cell lines and tumor cells from patients. In cancer cells, transfection of lv-miR-100 was able to upregulate endogenous expression of miR-100, inhibited cancer cell proliferation, and increased sensitivities to cisplatin. Overexpressing miR-100 led to significant inhibition on tumor formation in vivo. Luciferase essay showed FGFR3 was direct target of miR-100. FGFR3 was significantly downregulated by overexpressing miR-100 in pancreatic cancer cells and knocking down FGFR3 by siRNA exerted similar effect as miR-100. Our study demonstrated that miR-100 played an important role in pancreatic cancer development, possibly through targeting FGFR3. It may become a new therapeutic target for gene therapy in patients suffered from pancreatic cancer.

microRNA-137 modulates pancreatic cancer cells tumor growth, invasion and sensitivity to chemotherapy

PubMed Central

Xiao, Jie; Peng, Feng; Yu, Chao; Wang, Min; Li, Xu; Li, Zhipeng; Jiang, Jianxin; Sun, Chengyi

2014-01-01

Background: We intended to investigate the role of microRNA 137 (miR-137) in regulating pancreatic cancer cells’ growth in vitro and tumor development in vivo. Methods: QTR-PCR was used to examine the expression of miR-137 in pancreatic cancer cell lines and tumor cells from human patients. Lentivirual vector containing miR-137 mimic was used to overexpress miR-137 in PANC-1 and MIA PaCa-2 cells. The effects of overexpressing miR-137 on pancreatic cancer cell invasion and chemo-sensitivity to 5-fluorouracil (5-FU) were examined by cell migration and survival essays in vitro. The molecular target of miR-137, pleiotropic growth factor (PTN), was down-regulated by siRNA to examine its effects on cancer cell invasion. MIA PaCa-2 cells with endogenously overexpressed miR-137 were transplanted into null mice to examine tumor growth in vivo. Results: We found miR-137 was markedly underexpressed in both pancreatic cancer cell lines and tumor cells from patients. In cancer cells, transfection of lentivirus containing miR-137 mimic was able to markedly upregulate endogenous expression of miR-137, inhibited cancer cell invasion and increased sensitivities to chemotherapy reagent 5-FU. PTN was significantly down-regulated by overexpressing miR-137 in pancreatic cancer cells, and knocking down PTN was effective to rescue the reduced cancer cell invasion ability caused by miR-137 overexpression. More importantly, overexpressing miR-137 led to significant inhibition on tumor formation, including reductions in tumor weight and tumor size in vivo. Conclusion: Our study demonstrated that miR-137 played an important role in pancreatic cancer development. It may become a new therapeutic target for gene therapy in patients suffered from pancreatic cancer. PMID:25550779

GABA stimulates human hepatocellular carcinoma growth through overexpressed GABAA receptor theta subunit

PubMed Central

Li, Yue-Hui; Liu, Yan; Li, Yan-Dong; Liu, Yan-Hong; Li, Feng; Ju, Qiang; Xie, Ping-Li; Li, Guan-Cheng

2012-01-01

AIM: To investigate the function of gamma-aminobutyric acid (GABA) and gamma-aminobutyric acid A receptor θ subunit (GABRQ) in hepatocellular carcinoma (HCC). METHODS: Semiquantitative polymerase chain reaction was used for detecting the expression of GABRQ receptor among HCC cell line HepG2, normal liver cell line L-02, non-malignant Chang’s liver cells, 8 samples of HCC tissues and paired non-cancerous tissues. HepG2 cells were treated with GABA at serial concentrations (0, 1, 10, 20, 40 and 60 μmol/L), and their proliferating abilities were analyzed with the methyl thiazolyl tetrazolium assay, cell cycle analysis and tumor implanted in nude mice. Small interfering RNA was used for knocking down the endogenous GABRQ in HepG2. Proliferating abilities of these cells treated with or without GABA were analyzed. RESULTS: We identified the overexpression of GABRQ in HCC cell lines and half of the tested HCC tissues. Knockdown of endogenous GABRQ expression in HepG2 attenuated HCC cell growth, suggesting its role in HCC cell viability. We studied the effect of GABA in the proliferation of GABRQ-positive cell lines in vitro and in vivo, and found that GABA increased HCC growth in a dose-dependent manner. Notably, the addition of GABA into the cell culture medium promoted the proliferation of GABRQ-expressing HepG2 cells, but not GABRQ-knockdown HepG2 cells, which means that GABA stimulates HepG2 cell growth through GABRQ. CONCLUSION: GABRQ play important roles in HCC development and progression and could be a promising molecular target for the development of new diagnostic and therapeutic strategies of HCC. PMID:22690081

Different modes of APC/C activation control growth and neuron-glia interaction in the developing Drosophila eye.

PubMed

Neuert, Helen; Yuva-Aydemir, Yeliz; Silies, Marion; Klämbt, Christian

2017-12-15

The development of the nervous system requires tight control of cell division, fate specification and migration. The anaphase-promoting complex/cyclosome (APC/C) is an E3 ubiquitin ligase that affects different steps of cell cycle progression, as well as having postmitotic functions in nervous system development. It can therefore link different developmental stages in one tissue. The two adaptor proteins, Fizzy/Cdc20 and Fizzy-related/Cdh1, confer APC/C substrate specificity. Here, we show that two distinct modes of APC/C function act during Drosophila eye development. Fizzy/Cdc20 controls the early growth of the eye disc anlage and the concomitant entry of glial cells onto the disc. In contrast, fzr/cdh1 acts during neuronal patterning and photoreceptor axon growth, and subsequently affects neuron-glia interaction. To further address the postmitotic role of Fzr/Cdh1 in controlling neuron-glia interaction, we identified a series of novel APC/C candidate substrates. Four of our candidate genes are required for fzr/cdh1 -dependent neuron-glia interaction, including the dynein light chain Dlc90F Taken together, our data show how different modes of APC/C activation can couple early growth and neuron-glia interaction during eye disc development. © 2017. Published by The Company of Biologists Ltd.

Decapentaplegic and growth control in the developing Drosophila wing.

PubMed

Akiyama, Takuya; Gibson, Matthew C

2015-11-19

As a central model for morphogen action during animal development, the bone morphogenetic protein 2/4 (BMP2/4)-like ligand Decapentaplegic (Dpp) is proposed to form a long-range signalling gradient that directs both growth and pattern formation during Drosophila wing disc development. While the patterning role of Dpp secreted from a stripe of cells along the anterior-posterior compartmental boundary is well established, the mechanism by which a Dpp gradient directs uniform cell proliferation remains controversial and poorly understood. Here, to determine the precise spatiotemporal requirements for Dpp during wing disc development, we use CRISPR-Cas9-mediated genome editing to generate a flippase recognition target (FRT)-dependent conditional null allele. By genetically removing Dpp from its endogenous stripe domain, we confirm the requirement of Dpp for the activation of a downstream phospho-Mothers against dpp (p-Mad) gradient and the regulation of the patterning targets spalt (sal), optomotor blind (omb; also known as bifid) and brinker (brk). Surprisingly, however, third-instar wing blade primordia devoid of compartmental dpp expression maintain relatively normal rates of cell proliferation and exhibit only mild defects in growth. These results indicate that during the latter half of larval development, the Dpp morphogen gradient emanating from the anterior-posterior compartment boundary is not directly required for wing disc growth.

Development of basal endosperm transfer cells in Sorghum bicolor (L.) Moench and its relationship with caryopsis growth.

PubMed

Wang, Hui-Hui; Wang, Zhong; Wang, Feng; Gu, Yun-Jie; Liu, Zhi

2012-04-01

During sorghum caryopsis development, endosperm epidermal cells near the basal main vascular bundle are specialized by depositing wall ingrowths, differentiating into basal endosperm transfer cells (BETCs). All the BETCs together compose the basal endosperm transfer layer (BETL). BETCs are the first cell type to become histologically differentiated during endosperm development. The initiation and subsequent development of BETCs shows the pattern of temporal and spatial gradient. The developmental process of BETL can be divided into four stages: initiation, differentiation, functional, and apoptosis stage. A placental sac full of nutrient solutions would emerge, enlarge, and eventually disappear between the outmost layer of BETL and nucellar cells during caryopsis development. BETCs have dense cytoplasm rich in mitochondria, lamellar rough endoplasmic reticulum, Golgi bodies, and their secretory vesicles. They show a series of typical characteristics of senescence such as nuclei distortion and subcellular organelle deterioration during their specialization. BETCs probably play an active role in nutrient transfer into the starchy endosperm and embryo. The occurrence, development, and apoptosis of BETCs are in close relation to the caryopsis growth and maturation especially the enrichment of endosperm and the growth of embryo. The timing when BETL is fully developed, composed of three to four layers in radial direction and 70 to 80 rows in tangential direction, consists with the timing when average daily gain of caryopsis dry weight reaches its maximum. It is conceivable that measures that delay the senescence and death of BETCs would help to increase the crop yield.

Dual role of interleukin-17 in pannus growth and osteoclastogenesis in rheumatoid arthritis

PubMed Central

2011-01-01

Introduction In a murine model, interleukin (IL)-17 plays a critical role in the pathogenesis of arthritis. There are controversies, however, regarding whether IL-17 is a proinflammatory mediator in rheumatoid arthritis (RA). We previously established an ex vivo cellular model using synovial tissue (ST)-derived inflammatory cells, which reproduced pannus-like tissue growth and osteoclastic activity in vitro. Using this model, we investigated the effects of IL-17 on pannus growth and osteoclastogenesis in RA. Methods Inflammatory cells that infiltrated synovial tissue from patients with RA were collected without enzyme digestion and designated as ST-derived inflammatory cells. ST-derived inflammatory cells were cultured in the presence or absence of IL-17 or indomethacin, and the morphologic changes were observed for 4 weeks. Cytokines produced in the culture supernatants were measured by using enzyme-linked immunosorbent assay kits. Osteoclastic activity was assessed by the development of resorption pits in calcium phosphate-coated slides. Results Exogenous addition of IL-17 dramatically enhanced the spontaneous production of IL-6 and prostaglandin E2 (PGE2) by the ST-derived inflammatory cells, while it had no effect on the production of tumor necrosis factor (TNF)-α and macrophage colony-stimulating factor (M-CSF). Furthermore, IL-17 did not affect the spontaneous development of pannus-like tissue growth and osteoclastic activity by the ST-derived inflammatory cells. On the other hand, IL-17 enhanced pannus-like tissue growth, the production of TNF-α and M-CSF and the development of osteoclastic activity in the presence of indomethacin, an inhibitor of endogenous prostanoid production, while exogenous addition of PGE1 suppressed their activities. Conclusions The present study suggests that IL-17 induces negative feedback regulation through the induction of PGE2, while it stimulates proinflammatory pathways such as inflammatory cytokine production, pannus growth and osteoclastogenesis in RA. PMID:21294864

Hypoxia in cartilage: HIF-1alpha is essential for chondrocyte growth arrest and survival.

PubMed

Schipani, E; Ryan, H E; Didrickson, S; Kobayashi, T; Knight, M; Johnson, R S

2001-11-01

Breakdown or absence of vascular oxygen delivery is a hallmark of many common human diseases, including cancer, myocardial infarction, and stroke. The chief mediator of hypoxic response in mammalian tissues is the transcription factor hypoxia-inducible factor 1 (HIF-1), and its oxygen-sensitive component HIF-1alpha. A key question surrounding HIF-1alpha and the hypoxic response is the role of this transcription factor in cells removed from a functional vascular bed; in this regard there is evidence indicating that it can act as either a survival factor or induce growth arrest and apoptosis. To study more closely how HIF-1alpha functions in hypoxia in vivo, we used tissue-specific targeting to delete HIF-1alpha in an avascular tissue: the cartilaginous growth plate of developing bone. We show here the first evidence that the developmental growth plate in mammals is hypoxic, and that this hypoxia occurs in its interior rather than at its periphery. As a result of this developmental hypoxia, cells that lack HIF-1alpha in the interior of the growth plate die. This is coupled to decreased expression of the CDK inhibitor p57, and increased levels of BrdU incorporation in HIF-1alpha null growth plates, indicating defects in HIF-1alpha-regulated growth arrest occurs in these animals. Furthermore, we find that VEGF expression in the growth plate is regulated through both HIF-1alpha-dependent and -independent mechanisms. In particular, we provide evidence that VEGF expression is up-regulated in a HIF-1alpha-independent manner in chondrocytes surrounding areas of cell death, and this in turn induces ectopic angiogenesis. Altogether, our findings have important implications for the role of hypoxic response and HIF-1alpha in development, and in cell survival in tissues challenged by interruption of vascular flow; they also illustrate the complexities of HIF-1alpha response in vivo, and they provide new insights into mechanisms of growth plate development.

Why plants make puzzle cells, and how their shape emerges.

PubMed

Sapala, Aleksandra; Runions, Adam; Routier-Kierzkowska, Anne-Lise; Das Gupta, Mainak; Hong, Lilan; Hofhuis, Hugo; Verger, Stéphane; Mosca, Gabriella; Li, Chun-Biu; Hay, Angela; Hamant, Olivier; Roeder, Adrienne Hk; Tsiantis, Miltos; Prusinkiewicz, Przemyslaw; Smith, Richard S

2018-02-27

The shape and function of plant cells are often highly interdependent. The puzzle-shaped cells that appear in the epidermis of many plants are a striking example of a complex cell shape, however their functional benefit has remained elusive. We propose that these intricate forms provide an effective strategy to reduce mechanical stress in the cell wall of the epidermis. When tissue-level growth is isotropic, we hypothesize that lobes emerge at the cellular level to prevent formation of large isodiametric cells that would bulge under the stress produced by turgor pressure. Data from various plant organs and species support the relationship between lobes and growth isotropy, which we test with mutants where growth direction is perturbed. Using simulation models we show that a mechanism actively regulating cellular stress plausibly reproduces the development of epidermal cell shape. Together, our results suggest that mechanical stress is a key driver of cell-shape morphogenesis. © 2018, Sapala et al.

Why plants make puzzle cells, and how their shape emerges

PubMed Central

Routier-Kierzkowska, Anne-Lise; Das Gupta, Mainak; Hong, Lilan; Hofhuis, Hugo; Verger, Stéphane; Mosca, Gabriella; Li, Chun-Biu; Hay, Angela; Hamant, Olivier; Roeder, Adrienne HK; Tsiantis, Miltos; Prusinkiewicz, Przemyslaw

2018-01-01

The shape and function of plant cells are often highly interdependent. The puzzle-shaped cells that appear in the epidermis of many plants are a striking example of a complex cell shape, however their functional benefit has remained elusive. We propose that these intricate forms provide an effective strategy to reduce mechanical stress in the cell wall of the epidermis. When tissue-level growth is isotropic, we hypothesize that lobes emerge at the cellular level to prevent formation of large isodiametric cells that would bulge under the stress produced by turgor pressure. Data from various plant organs and species support the relationship between lobes and growth isotropy, which we test with mutants where growth direction is perturbed. Using simulation models we show that a mechanism actively regulating cellular stress plausibly reproduces the development of epidermal cell shape. Together, our results suggest that mechanical stress is a key driver of cell-shape morphogenesis. PMID:29482719

Regulation of pancreatic islet beta-cell mass by growth factor and hormone signaling.

PubMed

Huang, Yao; Chang, Yongchang

2014-01-01

Dysfunction and destruction of pancreatic islet beta cells is a hallmark of diabetes. Better understanding of cellular signals in beta cells will allow development of therapeutic strategies for diabetes, such as preservation and expansion of beta-cell mass and improvement of beta-cell function. During the past several decades, the number of studies analyzing the molecular mechanisms, including growth factor/hormone signaling pathways that impact islet beta-cell mass and function, has increased exponentially. Notably, somatolactogenic hormones including growth hormone (GH), prolactin (PRL), and insulin-like growth factor-1 (IGF-1) and their receptors (GHR, PRLR, and IGF-1R) are critically involved in beta-cell growth, survival, differentiation, and insulin secretion. In this chapter, we focus more narrowly on GH, PRL, and IGF-1 signaling, and GH-IGF-1 cross talk. We also discuss how these signaling aspects contribute to the regulation of beta-cell proliferation and apoptosis. In particular, our novel findings of GH-induced formation of GHR-JAK2-IGF-1R protein complex and synergistic effects of GH and IGF-1 on beta-cell signaling, proliferation, and antiapoptosis lead to a new concept that IGF-1R may serve as a proximal component of GH/GHR signaling. © 2014 Elsevier Inc. All rights reserved.

Antibacterial and anticancer PDMS surface for mammalian cell growth using the Chinese herb extract paeonol(4-methoxy-2-hydroxyacetophenone)

NASA Astrophysics Data System (ADS)

Jiao, Jiajia; Sun, Lili; Guo, Zaiyu; Hou, Sen; Holyst, Robert; Lu, Yun; Feng, Xizeng

2016-12-01

Polydimethylsiloxane (PDMS) is widely used as a cell culture platform to produce micro- and nano-technology based microdevices. However, the native PDMS surface is not suitable for cell adhesion and is always subject to bacterial pollution and cancer cell invasion. Coating the PDMS surface with antibacterial or anticancer materials often causes considerable harm to the non-cancer mammalian cells on it. We have developed a method to fabricate a biocompatible PDMS surface which not only promotes non-cancer mammalian cell growth but also has antibacterial and anticancer activities, by coating the PDMS surface with a Chinese herb extract, paeonol. Coating changes the wettability and the elemental composition of the PDMS surface. Molecular dynamic simulation indicates that the absorption of paeonol onto the PDMS surface is an energy favourable process. The paeonol-coated PDMS surface exhibits good antibacterial activity against both Gram-positive and Gram-negative bacteria. Moreover considerable antibacterial activity is maintained after the coated surface is rinsed or incubated in water. The coated PDMS surface inhibits bacterial growth on the contact surface and promotes non-cancer mammalian cell growth with low cell toxicity; meanwhile the growth of cancer cells is significantly inhibited. Our study will potentially guide PDMS surface modification approaches to produce biomedical devices.

Sensitivity of Candida Albicans Biofilm Cells Grown on Denture Acrylic to Antifungal Proteins and Chlorhexidine

PubMed Central

Pusateri, Christopher R.; Monaco, Edward A.; Edgerton, Mira

2009-01-01

Objectives Candida albicans cells form biofilms on polymeric surfaces of dentures and other prostheses introduced into the oral cavity. Many biofilm microorganisms exhibit resistance to antimicrobial agents; C. albicans cells may also develop resistance to naturally-occurring antifungal peptides in human saliva including histatins (Hsts) and defensins (hBDs). Therefore, we evaluated Hst 5 activity on C. albicans biofilm cells compared to planktonic cells and measured whether surface treatment of denture acrylic with Hst 5, hBD-3, or chlorhexidine gluconate could inhibit in vitro biofilm development. Methods Acrylic disks were preconditioned with 500 μl saliva for 30 min, and inoculated with C. albicans cells (106 cells/ml) for 1 h, at 37 °C. Non-adherent cells were removed by washing and disks and were incubated in YPD growth medium for 24, 48, and 72 h at 37 °C. Candidacidal assays were performed on 48-hour-biofilms and on planktonically-grown cells using Hst 5 (15.5 μM, 31.25 μM, 62 μM). Cell adhesion was compared on disks pre-coated with 0.12% chlorhexidine gluconate, 50 μM Hst 5, or 0.6 μM hBD-3 after 24 h, 48 h, and 72 h growth. Results No significant difference was observed in sensitivity to Hst 5 of biofilm cells compared to planktonic cells (p > 0.05). Pre-coating disks with hBD-3 did not inhibit biofilm development; however, Hst 5 significantly inhibited biofilm development at 72 h, while 0.12% chlorhexidine significantly inhibited biofilm development at all time intervals (p < 0.05). Conclusions C. albicans biofilm cells grown on denture acrylic are sensitive to killing by Hst 5. Surface coating acrylic with chlorhexidine or Hst 5 effectively inhibits biofilm growth and has potential therapeutic application. PMID:19249746

Single-cell analysis of S. cerevisiae growth recovery after a sublethal heat-stress applied during an alcoholic fermentation.

PubMed

Tibayrenc, Pierre; Preziosi-Belloy, Laurence; Ghommidh, Charles

2011-06-01

Interest in bioethanol production has experienced a resurgence in the last few years. Poor temperature control in industrial fermentation tanks exposes the yeast cells used for this production to intermittent heat stress which impairs fermentation efficiency. Therefore, there is a need for yeast strains with improved tolerance, able to recover from such temperature variations. Accordingly, this paper reports the development of methods for the characterization of Saccharomyces cerevisiae growth recovery after a sublethal heat stress. Single-cell measurements were carried out in order to detect cell-to-cell variability. Alcoholic batch fermentations were performed on a defined medium in a 2 l instrumented bioreactor. A rapid temperature shift from 33 to 43 °C was applied when ethanol concentration reached 50 g l⁻¹. Samples were collected at different times after the temperature shift. Single cell growth capability, lag-time and initial growth rate were determined by monitoring the growth of a statistically significant number of cells after agar medium plating. The rapid temperature shift resulted in an immediate arrest of growth and triggered a progressive loss of cultivability from 100 to 0.0001% within 8 h. Heat-injured cells were able to recover their growth capability on agar medium after a lag phase. Lag-time was longer and more widely distributed as the time of heat exposure increased. Thus, lag-time distribution gives an insight into strain sensitivity to heat-stress, and could be helpful for the selection of yeast strains of technological interest.

Tissue Engineering Using Transfected Growth-Factor Genes

NASA Technical Reports Server (NTRS)

Madry, Henning; Langer, Robert S.; Freed, Lisa E.; Trippel, Stephen; Vunjak-Novakovic, Gordana

2005-01-01

A method of growing bioengineered tissues includes, as a major component, the use of mammalian cells that have been transfected with genes for secretion of regulator and growth-factor substances. In a typical application, one either seeds the cells onto an artificial matrix made of a synthetic or natural biocompatible material, or else one cultures the cells until they secrete a desired amount of an extracellular matrix. If such a bioengineered tissue construct is to be used for surgical replacement of injured tissue, then the cells should preferably be the patient s own cells or, if not, at least cells matched to the patient s cells according to a human-leucocyteantigen (HLA) test. The bioengineered tissue construct is typically implanted in the patient's injured natural tissue, wherein the growth-factor genes enhance metabolic functions that promote the in vitro development of functional tissue constructs and their integration with native tissues. If the matrix is biodegradable, then one of the results of metabolism could be absorption of the matrix and replacement of the matrix with tissue formed at least partly by the transfected cells. The method was developed for articular chondrocytes but can (at least in principle) be extended to a variety of cell types and biocompatible matrix materials, including ones that have been exploited in prior tissue-engineering methods. Examples of cell types include chondrocytes, hepatocytes, islet cells, nerve cells, muscle cells, other organ cells, bone- and cartilage-forming cells, epithelial and endothelial cells, connective- tissue stem cells, mesodermal stem cells, and cells of the liver and the pancreas. Cells can be obtained from cell-line cultures, biopsies, and tissue banks. Genes, molecules, or nucleic acids that secrete factors that influence the growth of cells, the production of extracellular matrix material, and other cell functions can be inserted in cells by any of a variety of standard transfection techniques.

Stimulating Neoblast-Like Cell Proliferation in Juvenile Fasciola hepatica Supports Growth and Progression towards the Adult Phenotype In Vitro

PubMed Central

Rathinasamy, Vignesh; Toet, Hayley; McCammick, Erin; O’Connor, Anna; Marks, Nikki J.; Mousley, Angela; Brennan, Gerard P.; Halton, David W.; Spithill, Terry W.; Maule, Aaron G.

2016-01-01

Fascioliasis (or fasciolosis) is a socioeconomically important parasitic disease caused by liver flukes of the genus Fasciola. Flukicide resistance has exposed the need for new drugs and/or a vaccine for liver fluke control. A rapidly improving ‘molecular toolbox’ for liver fluke encompasses quality genomic/transcriptomic datasets and an RNA interference platform that facilitates functional genomics approaches to drug/vaccine target validation. The exploitation of these resources is undermined by the absence of effective culture/maintenance systems that would support in vitro studies on juvenile fluke development/biology. Here we report markedly improved in vitro maintenance methods for Fasciola hepatica that achieved 65% survival of juvenile fluke after 6 months in standard cell culture medium supplemented with 50% chicken serum. We discovered that this long-term maintenance was dependent upon fluke growth, which was supported by increased proliferation of cells resembling the “neoblast” stem cells described in other flatworms. Growth led to dramatic morphological changes in juveniles, including the development of the digestive tract, reproductive organs and the tegument, towards more adult-like forms. The inhibition of DNA synthesis prevented neoblast-like cell proliferation and inhibited growth/development. Supporting our assertion that we have triggered the development of juveniles towards adult-like fluke, mass spectrometric analyses showed that growing fluke have an excretory/secretory protein profile that is distinct from that of newly-excysted juveniles and more closely resembles that of ex vivo immature and adult fluke. Further, in vitro maintained fluke displayed a transition in their movement from the probing behaviour associated with migrating stage worms to a slower wave-like motility seen in adults. Our ability to stimulate neoblast-like cell proliferation and growth in F. hepatica underpins the first simple platform for their long-term in vitro study, complementing the recent expansion in liver fluke resources and facilitating in vitro target validation studies of the developmental biology of liver fluke. PMID:27622752

Interplay between TGF-β signaling and receptor tyrosine kinases in tumor development.

PubMed

Shi, Qiaoni; Chen, Ye-Guang

2017-10-01

Transforming growth factor-β (TGF-β) signaling regulates cell proliferation, differentiation, migration and death, and plays a critical role in embryogenesis and tissue homeostasis. Its deregulation results in various diseases including tumor formation. Receptor tyrosine kinases (RTKs), such as epidermal growth factor receptor (EGFR), fibroblast growth factor receptor (FGFR), vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR), also play key roles in the development and progression of many types of tumors. It has been realized that TGF-β signaling and RTK pathways interact with each other and their interplay is important for cancer development. They are mutually regulated and cooperatively modulate cell survival and migration, epithelial-mesenchymal transition, and tumor microenvironment to accelerate tumorigenesis and tumor metastasis. RTKs can modulate Smad-dependent transcription or cooperate with TGF-β to potentiate its oncogenic activity, while TGF-β signaling can in turn control RTK signaling by regulating their activities or expression. This review summarizes current understandings of the interplay between TGF-β signaling and RTKs and its influence on tumor development.

Oriented cell division shapes carnivorous pitcher leaves of Sarracenia purpurea

PubMed Central

Fukushima, Kenji; Fujita, Hironori; Yamaguchi, Takahiro; Kawaguchi, Masayoshi; Tsukaya, Hirokazu; Hasebe, Mitsuyasu

2015-01-01

Complex morphology is an evolutionary outcome of phenotypic diversification. In some carnivorous plants, the ancestral planar leaf has been modified to form a pitcher shape. However, how leaf development was altered during evolution remains unknown. Here we show that the pitcher leaves of Sarracenia purpurea develop through cell division patterns of adaxial tissues that are distinct from those in bifacial and peltate leaves, subsequent to standard expression of adaxial and abaxial marker genes. Differences in the orientation of cell divisions in the adaxial domain cause bifacial growth in the distal region and adaxial ridge protrusion in the middle region. These different growth patterns establish pitcher morphology. A computer simulation suggests that the cell division plane is critical for the pitcher morphogenesis. Our results imply that tissue-specific changes in the orientation of cell division underlie the development of a morphologically complex leaf. PMID:25774486

Oriented cell division shapes carnivorous pitcher leaves of Sarracenia purpurea.

PubMed

Fukushima, Kenji; Fujita, Hironori; Yamaguchi, Takahiro; Kawaguchi, Masayoshi; Tsukaya, Hirokazu; Hasebe, Mitsuyasu

2015-03-16

Complex morphology is an evolutionary outcome of phenotypic diversification. In some carnivorous plants, the ancestral planar leaf has been modified to form a pitcher shape. However, how leaf development was altered during evolution remains unknown. Here we show that the pitcher leaves of Sarracenia purpurea develop through cell division patterns of adaxial tissues that are distinct from those in bifacial and peltate leaves, subsequent to standard expression of adaxial and abaxial marker genes. Differences in the orientation of cell divisions in the adaxial domain cause bifacial growth in the distal region and adaxial ridge protrusion in the middle region. These different growth patterns establish pitcher morphology. A computer simulation suggests that the cell division plane is critical for the pitcher morphogenesis. Our results imply that tissue-specific changes in the orientation of cell division underlie the development of a morphologically complex leaf.

Gastrointestinal stromal tumors (GIST): Facing cell death between autophagy and apoptosis.

PubMed

Ravegnini, Gloria; Sammarini, Giulia; Nannini, Margherita; Pantaleo, Maria A; Biasco, Guido; Hrelia, Patrizia; Angelini, Sabrina

2017-03-04

Autophagy and apoptosis are 2 fundamental biological mechanisms that may cooperate or be antagonistic, although both are involved in deciding the fate of cells in physiological or pathological conditions. These 2 mechanisms coexist simultaneously in cells and share common upstream signals and stimuli. Autophagy and apoptosis play pivotal roles in cancer development. Autophagy plays a key function in maintaining tumor cell survival by providing energy during unfavorable metabolic conditions through its recycling mechanism, and supporting the high energy requirement for metabolism and growth. This review focuses on gastrointestinal stromal tumors and cell death through autophagy and apoptosis, taking into account the involvement of both of these processes in tumor development and growth and as mechanisms of drug resistance. We also focus on the crosstalk between autophagy and apoptosis as an emerging field with major implications for the development of novel therapeutic options.

Regulation of germ cell development by intercellular signaling in the mammalian ovarian follicle.

PubMed

Clarke, Hugh J

2018-01-01

Prior to ovulation, the mammalian oocyte undergoes a process of differentiation within the ovarian follicle that confers on it the ability to give rise to an embryo. Differentiation comprises two phases-growth, during which the oocyte increases more than 100-fold in volume as it accumulates macromolecules and organelles that will sustain early embryogenesis; and meiotic maturation, during which the oocyte executes the first meiotic division and prepares for the second division. Entry of an oocyte into the growth phase appears to be triggered when the adjacent granulosa cells produce specific growth factors. As the oocyte grows, it elaborates a thick extracellular coat termed the zona pellucida. Nonetheless, cytoplasmic extensions of the adjacent granulosa cells, termed transzonal projections (TZPs), enable them to maintain contact-dependent communication with the oocyte. Through gap junctions located where the TZP tips meet the oocyte membrane, they provide the oocyte with products that sustain its metabolic activity and signals that regulate its differentiation. Conversely, the oocyte secretes diffusible growth factors that regulate proliferation and differentiation of the granulosa cells. Gap junction-permeable products of the granulosa cells prevent precocious initiation of meiotic maturation, and the gap junctions also enable oocyte maturation to begin in response to hormonal signals received by the granulosa cells. Development of the oocyte or the somatic compartment may also be regulated by extracellular vesicles newly identified in follicular fluid and at TZP tips, which could mediate intercellular transfer of macromolecules. Oocyte differentiation thus depends on continuous signaling interactions with the somatic cells of the follicle. WIREs Dev Biol 2018, 7:e294. doi: 10.1002/wdev.294 This article is categorized under: Gene Expression and Transcriptional Hierarchies > Cellular Differentiation Signaling Pathways > Cell Fate Signaling Early Embryonic Development > Gametogenesis. © 2017 Wiley Periodicals, Inc.

Preclinical development of a bispecific antibody that safely and effectively targets CD19 and CD47 for the treatment of B cell lymphoma and leukemia.

PubMed

Buatois, Vanessa; Johnson, Zoë; Salgado-Pires, Susana; Papaïoannou, Anne; Hatterer, Eric; Chauchet, Xavier; Richard, Françoise; Barba, Leticia; Daubeuf, Bruno; Cons, Laura; Broyer, Lucile; D'Asaro, Matilde; Matthes, Thomas; LeGallou, Simon; Fest, Thierry; Tarte, Karin; Clarke Hinojosa, Robert K; Genescà Ferrer, Eulàlia; Ribera, José María; Dey, Aditi; Bailey, Katharine; Fielding, Adele K; Eissenberg, Linda; Ritchey, Julie; Rettig, Michael; DiPersio, John F; Kosco-Vilbois, Marie H; Masternak, Krzysztof; Fischer, Nicolas; Shang, Limin; Ferlin, Walter G

2018-05-09

CD47, a ubiquitously expressed innate immune checkpoint receptor that serves as a universal "don't eat me" signal of phagocytosis, is often up-regulated by hematological and solid cancers to evade immune surveillance. Development of CD47-targeted modalities is hindered by the ubiquitous expression of the target, often leading to rapid drug elimination and hemotoxicity including anemia. To overcome such liabilities, we have developed a fully human bispecific antibody, NI-1701, designed to co-engage CD47 and CD19 selectively on B cells. NI-1701 demonstrates favorable elimination kinetics with no deleterious effects seen on hematological parameters following single or multiple administrations to non-human primates. Potent in vitro and in vivo activity is induced by NI-1701 to kill cancer cells across a plethora of B cell malignancies and control tumor growth in xenograft mouse models. The mechanism affording maximal tumor growth inhibition by NI-1701 is dependent on the co-engagement of CD47/CD19 on B cells inducing potent antibody dependent cellular phagocytosis of the targeted cells. NI-1701-induced control of tumor growth in immunodeficient NOD/SCID mice was more effective than that achieved with the anti-CD20 targeted antibody, rituximab. Interestingly, a synergistic effect was seen when tumor-implanted mice were co-administered NI-1701 and rituximab leading to significantly improved tumor growth inhibition and regression in some animals. We describe herein, a novel bispecific antibody approach aimed at sensitizing B cells to become more readily phagocytosed and eliminated thus offering an alternative or adjunct therapeutic option to patients with B cell malignancies refractory/resistant to anti-CD20 targeted therapy. Copyright ©2018, American Association for Cancer Research.

Effect of benzo[a]pyrene on the production of vascular endothelial growth factor by human eosinophilic leukemia EoL-1 cells.

PubMed

Gu, Jie; Chan, Lai-Sheung; Wong, Chris Kong-Chu; Wong, Ngok-Shun; Wong, Chun-Kwok; Leung, Kok-Nam; Mak, Naiki K

2011-01-01

Benzo[a]pyrene (BaP) has been shown to affect both the development and response of T and B cells in the immune system. However, the effect of BaP on other immune cells, such as eosionophils, is unknown. In this study, we investigated the effect of BaP on the production of vascular endothelial growth factor (VEGF) using an in vitro eosinophilic EoL-1 cell and human umbilical vein endothelial cell (HUVEC) co-culture system. EoL-1-conditioned medium was found to promote the growth of HUVEC in a time-dependent manner. The growth stimulating activity was due to the production of VEGF by the EoL-1 cells. The production of VEGF was correlated with the enhanced expression of the phosphorylated form of extracellular signal-regulated kinases (p-ERKs) and the upregulated expression of VEGF mRNA. Furthermore, BaP-induced expression of VEGF mRNA was reduced by the ERK inhibitor PD98059. Results from this study suggested that BaP might affect the growth of endothelial cells through the modulation of VEGF production by eosinophils.

The reproductive-cell cycle theory of aging: an update.

PubMed

Atwood, Craig S; Bowen, Richard L

2011-01-01

The Reproductive-Cell Cycle Theory posits that the hormones that regulate reproduction act in an antagonistic pleiotrophic manner to control aging via cell cycle signaling; promoting growth and development early in life in order to achieve reproduction, but later in life, in a futile attempt to maintain reproduction, become dysregulated and drive senescence. Since reproduction is the most important function of an organism from the perspective of the survival of the species, if reproductive-cell cycle signaling factors determine the rate of growth, determine the rate of development, determine the rate of reproduction, and determine the rate of senescence, then by definition they determine the rate of aging and thus lifespan. The theory is able to explain: 1) the simultaneous regulation of the rate of aging and reproduction as evidenced by the fact that environmental conditions and experimental interventions known to extend longevity are associated with decreased reproductive-cell cycle signaling factors, thereby slowing aging and preserving fertility in a hostile reproductive environment; 2) two phenomena that are closely related to species lifespan-the rate of growth and development and the ultimate size of the animal; 3). the apparent paradox that size is directly proportional to lifespan and inversely proportional to fertility between species but vice versa within a species; 4). how differing rates of reproduction between species is associated with differences in their lifespan; 5). why we develop aging-related diseases; and 6). an evolutionarily credible reason for why and how aging occurs-these hormones act in an antagonistic pleiotrophic manner via cell cycle signaling; promoting growth and development early in life in order to achieve reproduction, but later in life, in a futile attempt to maintain reproduction, become dysregulated and drive senescence (dyosis). In essence, the Reproductive-Cell Cycle Theory can explain aging in all sexually reproductive life forms. Published by Elsevier Inc.

Mechanochemical switching between growth and differentiation during fibroblast growth factor-stimulated angiogenesis in vitro: role of extracellular matrix

PubMed Central

1989-01-01

The angiogenic factor, basic fibroblast growth factor (FGF), either stimulates endothelial cell growth or promotes capillary differentiation depending upon the microenvironment in which it acts. Analysis of various in vitro models of spontaneous angiogenesis, in combination with time-lapse cinematography, demonstrated that capillary tube formation was greatly facilitated by promoting multicellular retraction and cell elevation above the surface of the rigid culture dish or by culturing endothelial cells on malleable extracellular matrix (ECM) substrata. These observations suggested to us that mechanical (i.e., tension-dependent) interactions between endothelial cells and ECM may serve to regulate capillary development. To test this hypothesis, FGF-stimulated endothelial cells were grown in chemically defined medium on bacteriological (nonadhesive) dishes that were precoated with different densities of fibronectin. Extensive cell spreading and growth were promoted by fibronectin coating densities that were highly adhesive (greater than 500 ng/cm2), whereas cell rounding, detachment, and loss of viability were observed on dishes coated with low fibronectin concentrations (less than 100 ng/cm2). Intermediate fibronectin coating densities (100-500 ng/cm2) promoted cell extension, but they could not completely resist cell tractional forces. Partial retraction of multicellular aggregates resulted in cell shortening, cessation of growth, and formation of branching tubular networks within 24-48 h. Multicellular retraction and subsequent tube formation also could be elicited on highly adhesive dishes by overcoming the mechanical resistance of the substratum using higher cell plating numbers. Dishes coated with varying concentrations of type IV collagen or gelatin produced similar results. These results suggest that ECM components may act locally to regulate the growth and pattern- regulating actions of soluble FGF based upon their ability to resist cell-generated mechanical loads. Thus, we propose that FGF-stimulated endothelial cells may be "switched" between growth, differentiation, and involution modes during angiogenesis by altering the adhesivity or mechanical integrity of their ECM. PMID:2473081

PopZ identifies the new pole, and PodJ identifies the old pole during polar growth in Agrobacterium tumefaciens

PubMed Central

Grangeon, Romain; Zupan, John R.; Anderson-Furgeson, James; Zambryski, Patricia C.

2015-01-01

Agrobacterium tumefaciens elongates by addition of peptidoglycan (PG) only at the pole created by cell division, the growth pole, whereas the opposite pole, the old pole, is inactive for PG synthesis. How Agrobacterium assigns and maintains pole asymmetry is not understood. Here, we investigated whether polar growth is correlated with novel pole-specific localization of proteins implicated in a variety of growth and cell division pathways. The cell cycle of A. tumefaciens was monitored by time-lapse and superresolution microscopy to image the localization of A. tumefaciens homologs of proteins involved in cell division, PG synthesis and pole identity. FtsZ and FtsA accumulate at the growth pole during elongation, and improved imaging reveals FtsZ disappears from the growth pole and accumulates at the midcell before FtsA. The L,D-transpeptidase Atu0845 was detected mainly at the growth pole. A. tumefaciens specific pole-organizing protein (Pop) PopZAt and polar organelle development (Pod) protein PodJAt exhibited dynamic yet distinct behavior. PopZAt was found exclusively at the growing pole and quickly switches to the new growth poles of both siblings immediately after septation. PodJAt is initially at the old pole but then also accumulates at the growth pole as the cell cycle progresses suggesting that PodJAt may mediate the transition of the growth pole to an old pole. Thus, PopZAt is a marker for growth pole identity, whereas PodJAt identifies the old pole. PMID:26324921

Design and characterization of hybrid peptide sol-gel materials for the solid state induction of neuronal differentiation

NASA Astrophysics Data System (ADS)

Jedlicka, Sabrina S.

2007-12-01

Cell-based therapeutics are a rapidly growing area of research, with considerable promise in the treatment of neurological diseases. One of the primary limitations to neuronal cell-based devices is the necessity to maintain cells in an immature or undifferentiated state in culture prior to transplantation. In many cases, the undifferentiated cell does not express the desired characteristics for implantation. Biologically functional nanomaterials provide the ability to manipulate the direct extracellular environment surrounding cells; influencing their fate and differentiation path. The ability to engineer the interface between the cells and culture materials provides a repeatable, stable means of directing cells down a specific growth path determined by endogenous signaling pathways. This materials approach to cellular engineering can limit the need for added exogenous growth factors, "feeder" layers, or animal sera, in addition to creating a homogenous cell population for transplantation. In this work, hybrid peptide ormosil materials were developed; designed to mimic the developing mammalian brain during corticogenesis. These materials have been developed to enhance the GABAergic phenotype of P19 embryonic carcinoma cells and immature immortalized neurons. The ability to develop a homogenous, directed cell population has implications in stem cell research, regenerative medicine, cell-based devices and biosensing technology.

Transgenic mice overexpressing insulin-like growth factor-II in β cells develop type 2 diabetes

PubMed Central

Devedjian, Jean-Christophe; George, Monica; Casellas, Alba; Pujol, Anna; Visa, Joana; Pelegrín, Mireia; Gros, Laurent; Bosch, Fatima

2000-01-01

During embryonic development, insulin-like growth factor-II (IGF-II) participates in the regulation of islet growth and differentiation. We generated transgenic mice (C57BL6/SJL) expressing IGF-II in β cells under control of the rat Insulin I promoter in order to study the role of islet hyperplasia and hyperinsulinemia in the development of type 2 diabetes. In contrast to islets from control mice, islets from transgenic mice displayed high levels of IGF-II mRNA and protein. Pancreases from transgenic mice showed an increase in β-cell mass (about 3-fold) and in insulin mRNA levels. However, the organization of cells within transgenic islets was disrupted, with glucagon-producing cells randomly distributed throughout the core. We also observed enhanced glucose-stimulated insulin secretion and glucose utilization in islets from transgenic mice. These mice displayed hyperinsulinemia, mild hyperglycemia, and altered glucose and insulin tolerance tests, and about 30% of these animals developed overt diabetes when fed a high-fat diet. Furthermore, transgenic mice obtained from the N1 backcross to C57KsJ mice showed high islet hyperplasia and insulin resistance, but they also developed fatty liver and obesity. These results indicate that local overexpression of IGF-II in islets might lead to type 2 diabetes and that islet hyperplasia and hypersecretion of insulin might occur early in the pathogenesis of this disease. PMID:10727441

The Mechanism Forming the Cell Surface of Tip-Growing Rooting Cells Is Conserved among Land Plants.

PubMed

Honkanen, Suvi; Jones, Victor A S; Morieri, Giulia; Champion, Clement; Hetherington, Alexander J; Kelly, Steve; Proust, Hélène; Saint-Marcoux, Denis; Prescott, Helen; Dolan, Liam

2016-12-05

To discover mechanisms that controlled the growth of the rooting system in the earliest land plants, we identified genes that control the development of rhizoids in the liverwort Marchantia polymorpha. 336,000 T-DNA transformed lines were screened for mutants with defects in rhizoid growth, and a de novo genome assembly was generated to identify the mutant genes. We report the identification of 33 genes required for rhizoid growth, of which 6 had not previously been functionally characterized in green plants. We demonstrate that members of the same orthogroup are active in cell wall synthesis, cell wall integrity sensing, and vesicle trafficking during M. polymorpha rhizoid and Arabidopsis thaliana root hair growth. This indicates that the mechanism for constructing the cell surface of tip-growing rooting cells is conserved among land plants and was active in the earliest land plants that existed sometime more than 470 million years ago [1, 2]. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

mTORC1 and p53

PubMed Central

Hasty, Paul; Sharp, Zelton Dave; Curiel, Tyler J.; Campisi, Judith

2013-01-01

A balance must be struck between cell growth and stress responses to ensure that cells proliferate without accumulating damaged DNA. This balance means that optimal cell proliferation requires the integration of pro-growth and stress-response pathways. mTOR (mechanistic target of rapamycin) is a pleiotropic kinase found in complex 1 (mTORC1). The mTORC1 pathway governs a response to mitogenic signals with high energy levels to promote protein synthesis and cell growth. In contrast, the p53 DNA damage response pathway is the arbiter of cell proliferation, restraining mTORC1 under conditions of genotoxic stress. Recent studies suggest a complicated integration of these pathways to ensure successful cell growth and proliferation without compromising genome maintenance. Deciphering this integration could be key to understanding the potential clinical usefulness of mTORC1 inhibitors like rapamycin. Here we discuss how these p53-mTORC1 interactions might play a role in the suppression of cancer and perhaps the development of cellular senescence and organismal aging. PMID:23255104

Cytomegalovirus infection of the BS-1 human stroma cell line: effect on murine hemopoiesis.

PubMed

Steinberg, H N; Anderson, J; Lim, B; Chatis, P A

1993-10-01

BS-1, a stromal cell line derived from human bone marrow, can support the growth of murine erythroid (BFU-E), granulocyte-macrophage (CFU-GM), and megakaryocyte (CFU-M) progenitor cells in a short term in vitro coculture system. Exposure of BS-1 cells to cytomegalovirus (CMV) for 3 hr prior to coculture results in a marked reduction in the stroma cell's ability to support murine hemopoiesis. CMV's effect on the BS-1 cell's hematopoietic support function is dependent on the multiplicity of infection with total suppression of BFU-E observed at a 1:1 ratio of virus to bone marrow cells. A 50% loss in the ability of BS-1 cells to support BFU-E is observed at a 0.1:1 ratio. No effect of CMV is observed with further log dilutions of virus. CMV infection of BS-1 cells affects its support of erythroid progenitor cell growth to a greater extent than its influence on the development of granulocyte-macrophage colonies. Antibody to CMV or heat inactivation of the virus reverses the inhibitory affect on BS-1 cells. The results suggest that CMV can infect a cell that constitutes one of the cellular elements of the normal bone marrow microenvironment causing a decrease in the stroma's ability to support the growth and development of normal progenitor cells.

Quantification of growth factor signaling and pathway cross talk by live-cell imaging.

PubMed

Gross, Sean M; Rotwein, Peter

2017-03-01

Peptide growth factors stimulate cellular responses through activation of their transmembrane receptors. Multiple intracellular signaling cascades are engaged following growth factor-receptor binding, leading to short- and long-term biological effects. Each receptor-activated signaling pathway does not act in isolation but rather interacts at different levels with other pathways to shape signaling networks that are distinctive for each growth factor. To gain insights into the specifics of growth factor-regulated interactions among different signaling cascades, we developed a HeLa cell line stably expressing fluorescent live-cell imaging reporters that are readouts for two major growth factor-stimulated pathways, Ras-Raf-Mek-ERK and phosphatidylinositol (PI) 3-kinase-Akt. Incubation of cells with epidermal growth factor (EGF) resulted in rapid, robust, and sustained ERK signaling but shorter-term activation of Akt. In contrast, hepatocyte growth factor induced sustained Akt signaling but weak and short-lived ERK activity, and insulin-like growth factor-I stimulated strong long-term Akt responses but negligible ERK signaling. To address potential interactions between signaling pathways, we employed specific small-molecule inhibitors. In cells incubated with EGF or platelet-derived growth factor-AA, Raf activation and the subsequent stimulation of ERK reduced Akt signaling, whereas Mek inhibition, which blocked ERK activation, enhanced Akt and turned transient effects into sustained responses. Our results reveal that individual growth factors initiate signaling cascades that vary markedly in strength and duration and demonstrate in living cells the dramatic effects of cross talk from Raf and Mek to PI 3-kinase and Akt. Our data further indicate how specific growth factors can encode distinct cellular behaviors by promoting complex interactions among signaling pathways. Copyright © 2017 the American Physiological Society.

Quantification of growth factor signaling and pathway cross talk by live-cell imaging

PubMed Central

Gross, Sean M.

2017-01-01

Peptide growth factors stimulate cellular responses through activation of their transmembrane receptors. Multiple intracellular signaling cascades are engaged following growth factor–receptor binding, leading to short- and long-term biological effects. Each receptor-activated signaling pathway does not act in isolation but rather interacts at different levels with other pathways to shape signaling networks that are distinctive for each growth factor. To gain insights into the specifics of growth factor-regulated interactions among different signaling cascades, we developed a HeLa cell line stably expressing fluorescent live-cell imaging reporters that are readouts for two major growth factor-stimulated pathways, Ras–Raf–Mek–ERK and phosphatidylinositol (PI) 3-kinase–Akt. Incubation of cells with epidermal growth factor (EGF) resulted in rapid, robust, and sustained ERK signaling but shorter-term activation of Akt. In contrast, hepatocyte growth factor induced sustained Akt signaling but weak and short-lived ERK activity, and insulin-like growth factor-I stimulated strong long-term Akt responses but negligible ERK signaling. To address potential interactions between signaling pathways, we employed specific small-molecule inhibitors. In cells incubated with EGF or platelet-derived growth factor-AA, Raf activation and the subsequent stimulation of ERK reduced Akt signaling, whereas Mek inhibition, which blocked ERK activation, enhanced Akt and turned transient effects into sustained responses. Our results reveal that individual growth factors initiate signaling cascades that vary markedly in strength and duration and demonstrate in living cells the dramatic effects of cross talk from Raf and Mek to PI 3-kinase and Akt. Our data further indicate how specific growth factors can encode distinct cellular behaviors by promoting complex interactions among signaling pathways. PMID:28100485

CP-31398 prevents the growth of p53-mutated colorectal cancer cells in vitro and in vivo.

PubMed

He, Xingxing; Kong, Xinjuan; Yan, Junwei; Yan, Jingjun; Zhang, Yunan; Wu, Qian; Chang, Ying; Shang, Haitao; Dou, Qian; Song, Yuhu; Liu, Fang

2015-03-01

Rescuing the function of mutant p53 protein is an attractive cancer therapeutic strategy. Small molecule CP-31398 was shown to restore mutant p53 tumor suppressor functions in cancer cells. Here, we determined the effects of CP-31398 on the growth of p53-mutated colorectal cancer (CRC) cells in vitro and in vivo. CRC cells which carry p53 mutation in codon 273 were treated with CP-31398 and the control, and the effects of CP-31398 on cell cycle, cell apoptosis, and proliferation were determined. The expression of p53-responsive downstream genes was evaluated by quantitative reverse transcriptase PCR (RT-PCR) and Western blot. CP-31398 was administrated into xenograft tumors created by the inoculation of HT-29 cells, and then the effect of CP-31398 on the growth of xenograft tumors was examined. CP-31398 induced p53 downstream target molecules in cultured HT-29 cells, which resulted in the inhibition of CRC cell growth assessed by the determination of cell cycle, apoptosis, and cell proliferation. In xenograft tumors, CP-31398 modulated the expression of Bax, Bcl-2, caspase 3, cyclin D, and Mdm2 and then blocked the growth of xenograft tumors. CP-31398 would be developed as a therapeutic candidate for p53-mutated CRC due to the restoration of mutant p53 tumor suppressor functions.

Hypoxic exosomes facilitate bladder tumor growth and development through transferring long non-coding RNA-UCA1.

PubMed

Xue, Mei; Chen, Wei; Xiang, An; Wang, Ruiqi; Chen, He; Pan, Jingjing; Pang, Huan; An, Hongli; Wang, Xiang; Hou, Huilian; Li, Xu

2017-08-25

To overcome the hostile hypoxic microenvironment of solid tumors, tumor cells secrete a large number of non-coding RNA-containing exosomes that facilitate tumor development and metastasis. However, the precise mechanisms of tumor cell-derived exosomes during hypoxia are unknown. Here, we aim to clarify whether hypoxia affects tumor growth and progression by transferring long non-coding RNA-urothelial cancer-associated 1 (lncRNA-UCA1) enriched exosomes secreted from bladder cancer cells. We used bladder cancer 5637 cells with high expression of lncRNA-UCA1 as exosome-generating cells and bladder cancer UMUC2 cells with low expression of lncRNA-UCA1 as recipient cells. Exosomes derived from 5637 cells cultured under normoxic or hypoxic conditions were isolated and identified by transmission electron microscopy, nanoparticle tracking analysis and western blotting analysis. These exosomes were co-cultured with UMUC2 cells to evaluate cell proliferation, migration and invasion. We further investigated the roles of exosomal lncRNA-UCA1 derived from hypoxic 5637 cells by xenograft models. The availability of lncRNA-UCA1 in serum-derived exosomes as a biomarker for bladder cancer was also assessed. We found that hypoxic exosomes derived from 5637 cells promoted cell proliferation, migration and invasion, and hypoxic exosomal RNAs could be internalized by three bladder cancer cell lines. Importantly, lncRNA-UCA1 was secreted in hypoxic 5637 cell-derived exosomes. Compared with normoxic exosomes, hypoxic exosomes derived from 5637 cells showed the higher expression levels of lncRNA-UCA1. Moreover, Hypoxic exosomal lncRNA-UCA1 could promote tumor growth and progression though epithelial-mesenchymal transition, in vitro and in vivo. In addition, the expression levels of lncRNA-UCA1 in the human serum-derived exosomes of bladder cancer patients were higher than that in the healthy controls. Together, our results demonstrate that hypoxic bladder cancer cells remodel tumor microenvironment to facilitate tumor growth and development though secreting the oncogenic lncRNA-UCA1-enriched exosomes and exosomal lncRNA-UCA1 in human serum has the possibility as a diagnostic biomarker for bladder cancer.

Stochastic models for tumoral growth

NASA Astrophysics Data System (ADS)

Escudero, Carlos

2006-02-01

Strong experimental evidence has indicated that tumor growth belongs to the molecular beam epitaxy universality class. This type of growth is characterized by the constraint of cell proliferation to the tumor border and the surface diffusion of cells at the growing edge. Tumor growth is thus conceived as a competition for space between the tumor and the host, and cell diffusion at the tumor border is an optimal strategy adopted for minimizing the pressure and helping tumor development. Two stochastic partial differential equations are reported in this paper in order to correctly model the physical properties of tumoral growth in (1+1) and (2+1) dimensions. The advantage of these models is that they reproduce the correct geometry of the tumor and are defined in terms of polar variables. An analysis of these models allows us to quantitatively estimate the response of the tumor to an unfavorable perturbation during growth.

Constitutive Uncoupling of Pathways of Gene Expression That Control Growth and Differentiation in Myeloid Leukemia: A Model for the Origin and Progression of Malignancy

NASA Astrophysics Data System (ADS)

Sachs, Leo

1980-10-01

Chemical carcinogens and tumor promoters have pleiotropic effects. Tumor initiators can produce a variety of mutations and tumor promoters can regulate a variety of physiological molecules that control growth and differentiation. The appropriate mutation and the regulation of the appropriate molecules to induce cell growth can initiate and promote the sequence of changes required for transformation of normal cells into malignant cells. After this sequence of changes, some tumors can still be induced to revert with a high frequency from a malignant phenotype to a nonmalignant phenotype. Results obtained from analysis of regulation of growth and differentiation in normal and leukemic myeloid cells, the phenotypic reversion of malignancy by induction of normal differentiation in myeloid leukemia, and the blocks in differentiation-defective leukemic cell mutants have been used to propose a general model for the origin and progression of malignancy. The model states that malignancy originates by changing specific pathways of gene expression required for growth from inducible to constitutive in cells that can still be induced to differentiate normally by the physiological inducer of differentiation. The malignant cells, unlike the normal cells, then no longer require the physiological inducer for growth. This changes the requirements for growth and uncouples growth from differentiation. Constitutive expression of other specific pathways can uncouple other controls, which then causes blocks in differentiation and the further progression of malignancy. The existence of specific constitutive pathways of gene expression that uncouple controls in malignant cells can also explain the expression of fetal proteins, hormones, and some other specialized products of normal development in various types of tumors.

Tcf3 and cell cycle factors contribute to butyrate resistance in colorectal cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiaro, Christopher, E-mail: cchiaro@tcmedc.org; Lazarova, Darina L., E-mail: dlazarova@tcmedc.org; Bordonaro, Michael, E-mail: mbordonaro@tcmedc.org

2012-11-09

Highlights: Black-Right-Pointing-Pointer We investigate mechanisms responsible for butyrate resistance in colon cancer cells. Black-Right-Pointing-Pointer Tcf3 modulates butyrate's effects on Wnt activity and cell growth in resistant cells. Black-Right-Pointing-Pointer Tcf3 modulation of butyrate's effects differ by cell context. Black-Right-Pointing-Pointer Cell cycle factors are overexpressed in the resistant cells. Black-Right-Pointing-Pointer Reversal of altered gene expression can enhance the anti-cancer effects of butyrate. -- Abstract: Butyrate, a fermentation product of dietary fiber, inhibits clonal growth in colorectal cancer (CRC) cells dependent upon the fold induction of Wnt activity. We have developed a CRC cell line (HCT-R) that, unlike its parental cell line, HCT-116,more » does not respond to butyrate exposure with hyperactivation of Wnt signaling and suppressed clonal growth. PCR array analyses revealed Wnt pathway-related genes, the expression of which differs between butyrate-sensitive HCT-116 CRC cells and their butyrate-resistant HCT-R cell counterparts. We identified overexpression of Tcf3 as being partially responsible for the butyrate-resistant phenotype, as this DNA-binding protein suppresses the hyperinduction of Wnt activity by butyrate. Consequently, Tcf3 knockdown in HCT-R cells restores their sensitivity to the effects of butyrate on Wnt activity and clonal cell growth. Interestingly, the effects of overexpressed Tcf3 differ between HCT-116 and HCT-R cells; thus, in HCT-116 cells Tcf3 suppresses proliferation without rendering the cells resistant to butyrate. In HCT-R cells, however, the overexpression of Tcf3 inhibits Wnt activity, and the cells are still able to proliferate due to the higher expression levels of cell cycle factors, particularly those driving the G{sub 1} to S transition. Knowledge of the molecular mechanisms determining the variable sensitivity of CRC cells to butyrate may assist in developing approaches that prevent or reverse butyrate resistance.« less

The Rice Receptor-Like Kinases DWARF AND RUNTISH SPIKELET1 and 2 Repress Cell Death and Affect Sugar Utilization during Reproductive Development

PubMed Central

Song, Feng-Yan; Zhao, Ying; Wang, Chun-Yan; Zhang, Yong-Cun; Yang, Qian; Wang, Jiao; Bu, Shuo-Lei; Sun, Li-Jing; Zhang, Sheng-Wei; Zhang, Su-Qiao; Sun, Da-Ye

2017-01-01

Cell-to-cell communication precisely controls the creation of new organs during reproductive growth. However, the sensor molecules that mediate developmental signals in monocot plants are poorly understood. Here, we report that DWARF AND RUNTISH SPIKELET1 (DRUS1) and DRUS2, two closely related receptor-like kinases (RLKs), redundantly control reproductive growth and development in rice (Oryza sativa). A drus1-1 drus2 double knockout mutant, but not either single mutant, showed extreme dwarfism and barren inflorescences that harbored sterile spikelets. The gibberellin pathway was not impaired in this mutant. A phenotypic comparison of mutants expressing different amounts of DRUS1 and 2 revealed that reproductive growth requires a threshold level of DRUS1/2 proteins. DRUS1 and 2 maintain cell viability by repressing protease-mediated cell degradation and likely by affecting sugar utilization or conversion. In the later stages of anther development, survival of the endothecium requires DRUS1/2, which may stimulate expression of the UDP-glucose pyrophosphorylase gene UGP2 and starch biosynthesis in pollen. Unlike their Arabidopsis thaliana ortholog FERONIA, DRUS1 and 2 mediate a fundamental signaling process that is essential for cell survival and represents a novel biological function for the CrRLK1L RLK subfamily. PMID:28082384

Stem cell function during plant vascular development

PubMed Central

Miyashima, Shunsuke; Sebastian, Jose; Lee, Ji-Young; Helariutta, Yka

2013-01-01

The plant vascular system, composed of xylem and phloem, evolved to connect plant organs and transport various molecules between them. During the post-embryonic growth, these conductive tissues constitutively form from cells that are derived from a lateral meristem, commonly called procambium and cambium. Procambium/cambium contains pluripotent stem cells and provides a microenvironment that maintains the stem cell population. Because vascular plants continue to form new tissues and organs throughout their life cycle, the formation and maintenance of stem cells are crucial for plant growth and development. In this decade, there has been considerable progress in understanding the molecular control of the organization and maintenance of stem cells in vascular plants. Noticeable advance has been made in elucidating the role of transcription factors and major plant hormones in stem cell maintenance and vascular tissue differentiation. These studies suggest the shared regulatory mechanisms among various types of plant stem cell pools. In this review, we focus on two aspects of stem cell function in the vascular cambium, cell proliferation and cell differentiation. PMID:23169537

The key players of the primary root growth and development also function in lateral roots in Arabidopsis.

PubMed

Tian, Huiyu; Jia, Yuebin; Niu, Tiantian; Yu, Qianqian; Ding, Zhaojun

2014-05-01

The core regulators which are required for primary root growth and development also function in lateral root development or lateral root stem cell niche maintenance. The primary root systems and the lateral root systems are the two important root systems which are vital to the survival of plants. Though the molecular mechanism of the growth and development of both the primary root systems and the lateral root systems have been extensively studied individually in Arabidopsis, there are not so much evidence to show that if both root systems share common regulatory mechanisms. AP2 family transcription factors such as PLT1 (PLETHORA1) and PLT2, GRAS family transcription factors such as SCR (SCARECROW) and SHR (SHORT ROOT) and WUSCHEL-RELATED HOMEOBOX transcription factor WOX5 have been extensively studied and found to be essential for primary root growth and development. In this study, through the expression pattern analysis and mutant examinations, we found that these core regulators also function in lateral root development or lateral root stem cell niche maintenance.

A c-fms tyrosine kinase inhibitor, Ki20227, suppresses osteoclast differentiation and osteolytic bone destruction in a bone metastasis model.

PubMed

Ohno, Hiroaki; Kubo, Kazuo; Murooka, Hideko; Kobayashi, Yoshiko; Nishitoba, Tsuyoshi; Shibuya, Masabumi; Yoneda, Toshiyuki; Isoe, Toshiyuki

2006-11-01

In bone metastatic lesions, osteoclasts play a key role in the development of osteolysis. Previous studies have shown that macrophage colony-stimulating factor (M-CSF) is important for the differentiation of osteoclasts. In this study, we investigated whether an inhibitor of M-CSF receptor (c-Fms) suppresses osteoclast-dependent osteolysis in bone metastatic lesions. We developed small molecule inhibitors against ligand-dependent phosphorylation of c-Fms and examined the effects of these compounds on osteolytic bone destruction in a bone metastasis model. We discovered a novel quinoline-urea derivative, Ki20227 (N-{4-[(6,7-dimethoxy-4-quinolyl)oxy]-2-methoxyphenyl}-N'-[1-(1,3-thiazole-2-yl)ethyl]urea), which is a c-Fms tyrosine kinase inhibitor. The IC(50)s of Ki20227 to inhibit c-Fms, vascular endothelial growth factor receptor-2 (KDR), stem cell factor receptor (c-Kit), and platelet-derived growth factor receptor beta were found to be 2, 12, 451, and 217 nmol/L, respectively. Ki20227 did not inhibit other kinases tested, such as fms-like tyrosine kinase-3, epidermal growth factor receptor, or c-Src (c-src proto-oncogene product). Ki20227 was also found to inhibit the M-CSF-dependent growth of M-NFS-60 cells but not the M-CSF-independent growth of A375 human melanoma cells in vitro. Furthermore, in an osteoclast-like cell formation assay using mouse bone marrow cells, Ki20227 inhibited the development of tartrate-resistant acid phosphatase-positive osteoclast-like cells in a dose-dependent manner. In in vivo studies, oral administration of Ki20227 suppressed osteoclast-like cell accumulation and bone resorption induced by metastatic tumor cells in nude rats following intracardiac injection of A375 cells. Moreover, Ki20227 decreased the number of tartrate-resistant acid phosphatase-positive osteoclast-like cells on bone surfaces in ovariectomized (ovx) rats. These findings suggest that Ki20227 inhibits osteolytic bone destruction through the suppression of M-CSF-induced osteoclast accumulation in vivo. Therefore, Ki20227 may be a useful therapeutic agent for osteolytic disease associated with bone metastasis and other bone diseases.

L-Arginine promotes protein synthesis and cell growth in brown adipocyte precursor cells via the mTOR signal pathway.

PubMed

Ma, Xi; Han, Meng; Li, Defa; Hu, Shengdi; Gilbreath, Kyler R; Bazer, Fuller W; Wu, Guoyao

2017-05-01

L-Arginine has been reported to enhance brown adipose tissue developments in fetal lambs of obese ewes, but the underlying mechanism is unknown. The present study tested the hypothesis that L-arginine stimulates growth and development of brown adipocyte precursor cells (BAPCs) through activation of mammalian target of rapamycin cell signaling. BAPCs isolated from fetal lambs at day 90 of gestation were incubated   for 6 h in arginine-free DMEM, and then cultured in DMEM with concentrations of 50, 100, 200, 500 or 1000 μmol L-arginine/L for 24-96 h. Cell proliferation, protein turnover, the mammalian target of rapamycin (mTOR) signaling pathway and pre-adipocyte differentiation markers were determined. L-arginine treatment enhanced (P < 0.05) BAPC growth and protein synthesis, while inhibiting proteolysis in a dose-dependent manner. Compared with 50 and 100 μmol/L (the concentrations of arginine in the maternal plasma of obese ewes), 200 μmol L-arginine/L (the concentrations of arginine in the maternal plasma of obese ewes receiving arginine supplementation) increased (P < 0.05) the abundances of phosphorylated mTOR, P70 S6K and 4EBP1, as well as the abundances of PGC1α, UCP1, BMP7 and PRDM16. These novel findings indicate that increasing extra-cellular arginine concentration from 50 to 200 µmol/L activates mTOR cell signaling in BAPCs and enhances their growth and development in a dose-dependent manner. Our results provide a mechanism for arginine supplementation to enhance the development of brown adipose tissue in fetal lambs.

Converging Light, Energy and Hormonal Signaling Control Meristem Activity, Leaf Initiation, and Growth1[CC-BY

PubMed Central

Mohammed, Binish; Bilooei, Sara Farahi; Grove, Elliot; Railo, Saana; Palme, Klaus

2018-01-01

The development of leaf primordia is subject to light control of meristematic activity. Light regulates the expression of thousands of genes with roles in cell proliferation, organ development, and differentiation of photosynthetic cells. Previous work has highlighted roles for hormone homeostasis and the energy-dependent Target of Rapamycin (TOR) kinase in meristematic activity, yet a picture of how these two regulatory mechanisms depend on light perception and interact with each other has yet to emerge. Their relevance beyond leaf initiation also is unclear. Here, we report the discovery that the dark-arrested meristematic region of Arabidopsis (Arabidopsis thaliana) experiences a local energy deprivation state and confirm previous findings that the PIN1 auxin transporter is diffusely localized in the dark. Light triggers a rapid removal of the starvation state and the establishment of PIN1 polar membrane localization consistent with auxin export, both preceding the induction of cell cycle- and cytoplasmic growth-associated genes. We demonstrate that shoot meristematic activity can occur in the dark through the manipulation of auxin and cytokinin activity as well as through the activation of energy signaling, both targets of photomorphogenesis action, but the organ developmental outcomes differ: while TOR-dependent energy signals alone stimulate cell proliferation, the development of a normal leaf lamina requires photomorphogenesis-like hormonal responses. We further show that energy signaling adjusts the extent of cell cycle activity and growth of young leaves non-cellautonomously to available photosynthates and leads to organs constituted of a greater number of cells developing under higher irradiance. This makes energy signaling perhaps the most important biomass growth determinant under natural, unstressed conditions. PMID:29284741

Regulation of tomato fruit pericarp development by an interplay between CDKB and CDKA1 cell cycle genes

PubMed Central

Czerednik, Anna; Busscher, Marco; Bielen, Bram A.M.; Wolters-Arts, Mieke; de Maagd, Ruud A.; Angenent, Gerco C.

2012-01-01

Growth of tomato fruits is determined by cell division and cell expansion, which are tightly controlled by factors that drive the core cell cycle. The cyclin-dependent kinases (CDKs) and their interacting partners, the cyclins, play a key role in the progression of the cell cycle. In this study the role of CDKA1, CDKB1, and CDKB2 in fruit development was characterized by fruit-specific overexpression and down-regulation. CDKA1 is expressed in the pericarp throughout development, but is strongly up-regulated in the outer pericarp cell layers at the end of the growth period, when CDKB gene expression has ceased. Overexpression of the CDKB genes at later stages of development and the down-regulation of CDKA1 result in a very similar fruit phenotype, showing a reduction in the number of cell layers in the pericarp and alterations in the desiccation of the fruits. Expression studies revealed that CDKA1 is down-regulated by the expression of CDKB1/2 in CDKB1 and CDKB2 overexpression mutants, suggesting opposite roles for these types of CDK proteins in tomato pericarp development. PMID:22282536

Computer modeling of dendritic web growth processes and characterization of the material

NASA Technical Reports Server (NTRS)

Seidensticker, R. G.; Kothmann, R. E.; Mchugh, J. P.; Duncan, C. S.; Hopkins, R. H.; Blais, P. D.; Davis, J. R.; Rohatgi, A.

1978-01-01

High area throughput rate will be required for the economical production of silicon dendritic web for solar cells. Web width depends largely on the temperature distribution on the melt surface while growth speed is controlled by the dissipation of the latent heat of fusion. Thermal models were developed to investigate each of these aspects, and were used to engineer the design of laboratory equipment capable of producing crystals over 4 cm wide; growth speeds up to 10 cm/min were achieved. The web crystals were characterized by resistivity, lifetime and etch pit density data as well as by detailed solar cell I-V data. Solar cells ranged in efficiency from about 10 to 14.5% (AM-1) depending on growth conditions. Cells with lower efficiency displayed lowered bulk lifetime believed to be due to surface contamination.

Control of B Lymphocyte Development and Functions by the mTOR Signaling Pathways

PubMed Central

Iwata, Terri N.; Ramírez-Komo, Julita A.; Park, Heon; Iritani, Brian M.

2017-01-01

Mechanistic target of rapamycin (mTOR) is a serine/threonine kinase originally discovered as the molecular target of the immunosuppressant rapamycin. mTOR forms two compositionally and functionally distinct complexes, mTORC1 and mTORC2, which are crucial for coordinating nutrient, energy, oxygen, and growth factor availability with cellular growth, proliferation, and survival. Recent studies have identified critical, non-redundant roles for mTORC1 and mTORC2 in controlling B cell development, differentiation, and functions, and have highlighted emerging roles of the Folliculin-Fnip protein complex in regulating mTOR and B cell development. In this review, we summarize the basic mechanisms of mTOR signaling; describe what is known about the roles of mTORC1, mTORC2, and the Folliculin/Fnip1 pathway in B cell development and functions; and briefly outline current clinical approaches for targeting mTOR in B cell neoplasms. We conclude by highlighting a few salient questions and future perspectives regarding mTOR in B lineage cells. PMID:28583723

Synapse maintenance and restoration in the retina by NGL2

PubMed Central

Zhao, Lei

2018-01-01

Synaptic cell adhesion molecules (CAMs) promote synapse formation in the developing nervous system. To what extent they maintain and can restore connections in the mature nervous system is unknown. Furthermore, how synaptic CAMs affect the growth of synapse-bearing neurites is unclear. Here, we use adeno-associated viruses (AAVs) to delete, re-, and overexpress the synaptic CAM NGL2 in individual retinal horizontal cells. When we removed NGL2 from horizontal cells, their axons overgrew and formed fewer synapses, irrespective of whether Ngl2 was deleted during development or in mature circuits. When we re-expressed NGL2 in knockout mice, horizontal cell axon territories and synapse numbers were restored, even if AAVs were injected after phenotypes had developed. Finally, overexpression of NGL2 in wild-type horizontal cells elevated synapse numbers above normal levels. Thus, NGL2 promotes the formation, maintenance, and restoration of synapses in the developing and mature retina, and restricts axon growth throughout life. PMID:29553369

Fibroblast growth factor receptor signaling is essential for lens fiber cell differentiation.

PubMed

Zhao, Haotian; Yang, Tianyu; Madakashira, Bhavani P; Thiels, Cornelius A; Bechtle, Chad A; Garcia, Claudia M; Zhang, Huiming; Yu, Kai; Ornitz, David M; Beebe, David C; Robinson, Michael L

2008-06-15

The vertebrate lens provides an excellent model to study the mechanisms that regulate terminal differentiation. Although fibroblast growth factors (FGFs) are thought to be important for lens cell differentiation, it is unclear which FGF receptors mediate these processes during different stages of lens development. Deletion of three FGF receptors (Fgfr1-3) early in lens development demonstrated that expression of only a single allele of Fgfr2 or Fgfr3 was sufficient for grossly normal lens development, while mice possessing only a single Fgfr1 allele developed cataracts and microphthalmia. Profound defects were observed in lenses lacking all three Fgfrs. These included lack of fiber cell elongation, abnormal proliferation in prospective lens fiber cells, reduced expression of the cell cycle inhibitors p27(kip1) and p57(kip2), increased apoptosis and aberrant or reduced expression of Prox1, Pax6, c-Maf, E-cadherin and alpha-, beta- and gamma-crystallins. Therefore, while signaling by FGF receptors is essential for lens fiber differentiation, different FGF receptors function redundantly.

Curcumin synergizes the growth inhibitory properties of Indian toad (Bufo melanostictus Schneider) skin-derived factor (BM-ANF1) in HCT-116 colon cancer cells.

PubMed

Giri, Biplab; Gomes, Antony; Sengupta, Radha; Banerjee, Sanjeev; Nautiyal, Jyoti; Sarkar, Fazlul H; Majumdar, Adhip P N

2009-01-01

Curcumin, an active ingredient of turmeric with no discernable toxicity, inhibits the growth of transformed cells and the development and progression of colon carcinogenesis in experimental animals. Recent data from one of our laboratories demonstrated that a crude skin extract or a purified crystalline compound (Bufo melanostictus-antineoplastic factor 1, BM-ANF1) from Indian common toad (Bufo melanostictus, Schneider) skin inhibits the growth of human leukemic cells. The present investigation was undertaken to determine whether combining BM-ANF1 with curcumin would be a better therapeutic strategy for colon cancer. Colon cancer HCT-116 cells were used. Changes in growth, apoptosis, growth factor receptor signaling and events of the cell cycle were analyzed. Curcumin together with BM-ANF1 produced a greater inhibition of HCT-116 cells growth than either agent alone, attributable to the inhibition of proliferation and stimulation of apoptosis, as evidenced by suppression of proliferating cell nuclear antigen (PCNA) expression, cell cycle arrest at the G2/M-phase and caspase-3 activation. There was also a marked reduction of cyclin-dependent kinase (CDK)2, CDK4 and cyclin B expression and up-regulation of CDK inhibitors (p21, p27) and p53, accompanied by attenuation of Akt signaling and nuclear factor-kappa B (NF-kappaB) activation. BM-ANF1 in combination with curcumin causes a marked inhibition of growth of colon cancer cells and could be an effective therapeutic strategy for colon cancer.

KSA Antigen Ep-CAM Mediates Cell–Cell Adhesion of Pancreatic Epithelial Cells: Morphoregulatory Roles in Pancreatic Islet Development

PubMed Central

Cirulli, V.; Crisa, L.; Beattie, G.M.; Mally, M.I.; Lopez, A.D.; Fannon, A.; Ptasznik, A.; Inverardi, L.; Ricordi, C.; Deerinck, T.; Ellisman, M.; Reisfeld, R.A.; Hayek, A.

1998-01-01

Cell adhesion molecules (CAMs) are important mediators of cell–cell interactions and regulate cell fate determination by influencing growth, differentiation, and organization within tissues. The human pancarcinoma antigen KSA is a glycoprotein of 40 kD originally identified as a marker of rapidly proliferating tumors of epithelial origin. Interestingly, most normal epithelia also express this antigen, although at lower levels, suggesting that a dynamic regulation of KSA may occur during cell growth and differentiation. Recently, evidence has been provided that this glycoprotein may function as an epithelial cell adhesion molecule (Ep-CAM). Here, we report that Ep-CAM exhibits the features of a morphoregulatory molecule involved in the development of human pancreatic islets. We demonstrate that Ep-CAM expression is targeted to the lateral domain of epithelial cells of the human fetal pancreas, and that it mediates calcium-independent cell–cell adhesion. Quantitative confocal immunofluorescence in fetal pancreata identified the highest levels of Ep-CAM expression in developing islet-like cell clusters budding from the ductal epithelium, a cell compartment thought to comprise endocrine progenitors. A surprisingly reversed pattern was observed in the human adult pancreas, displaying low levels of Ep-CAM in islet cells and high levels in ducts. We further demonstrate that culture conditions promoting epithelial cell growth induce upregulation of Ep-CAM, whereas endocrine differentiation of fetal pancreatic epithelial cells, transplanted in nude mice, is associated with a downregulation of Ep-CAM expression. In addition, a blockade of Ep-CAM function by KS1/4 mAb induced insulin and glucagon gene transcription and translation in fetal pancreatic cell clusters. These results indicate that developmentally regulated expression and function of Ep-CAM play a morphoregulatory role in pancreatic islet ontogeny. PMID:9508783

Effects of salinity on the transcriptome of growing maize leaf cells point at cell-age specificity in the involvement of the antioxidative response in cell growth restriction

PubMed Central

2013-01-01

Background Salinity inhibits growth and development of most plants. The response to salinity is complex and varies between plant organs and stages of development. It involves challenges of ion toxicities and deficiencies as well as osmotic and oxidative stresses. The range of functions affected by the stress is reflected in elaborate changes to the transcriptome. The mechanisms involved in the developmental-stage specificity of the inhibitory responses are not fully understood. The present study took advantage of the well characterized developmental progression that exists along the maize leaf, for identification of salinity induced, developmentally-associated changes to the transcriptome. Differential subtraction screening was conducted for cells of two developmental stages: from the center of the growth zone where the expansion rate is highest, and from older cells at a more distal location of the growing zone where the expansion rate is lower and the salinity restrictive effects are more pronounced. Real-Time PCR analysis was used for validation of the expression of selected genes. Results The salinity-induced changes demonstrated an age-related response of the growing tissue, with elevation of salinity-damages with increased age. Growth reduction, similar to the elevation of percentage dry matter (%DM), and Na and Cl concentrations were more pronounced in the older cells. The differential subtraction screening identified genes encoding to proteins involved in antioxidant defense, electron transfer and energy, structural proteins, transcription factors and photosynthesis proteins. Of special interest is the higher induced expression of genes involved in antioxidant protection in the young compared to older cells, which was accompanied by suppressed levels of reactive oxygen species (H2O2 and O2-). This was coupled with heightened expression in the older cells of genes that enhance cell-wall rigidity, which points at reduced potential for cell expansion. Conclusions The results demonstrate a cell-age specificity in the salinity response of growing cells, and point at involvement of the antioxidative response in cell growth restriction. Processes involved in reactive oxygen species (ROS) scavenging are more pronounced in the young cells, while the higher growth sensitivity of older cells is suggested to involve effects on cell-wall rigidity and lower protein protection. PMID:23324477

Cell dynamics in cervical loop epithelium during transition from crown to root: implications for Hertwig's epithelial root sheath formation.

PubMed

Sakano, M; Otsu, K; Fujiwara, N; Fukumoto, S; Yamada, A; Harada, H

2013-04-01

Some clinical cases of hypoplastic tooth root are congenital. Because the formation of Hertwig's epithelial root sheath (HERS) is an important event for root development and growth, we have considered that understanding the HERS developmental mechanism contributes to elucidate the causal factors of the disease. To find integrant factors and phenomenon for HERS development and growth, we studied the proliferation and mobility of the cervical loop (CL). We observed the cell movement of CL by the DiI labeling and organ culture system. To examine cell proliferation, we carried out immunostaining of CL and HERS using anti-Ki67 antibody. Cell motility in CL was observed by tooth germ slice organ culture using green fluorescent protein mouse. We also examined the expression of paxillin associated with cell movement. Imaging using DiI labeling showed that, at the apex of CL, the epithelium elongated in tandem with the growth of outer enamel epithelium (OEE). Cell proliferation assay using Ki67 immunostaining showed that OEE divided more actively than inner enamel epithelium (IEE) at the onset of HERS formation. Live imaging suggested that mobility of the OEE and cells in the apex of CL were more active than in IEE. The expression of paxillin was observed strongly in OEE and the apex of CL. The more active growth and movement of OEE cells contributed to HERS formation after reduction of the growth of IEE. The expression pattern of paxillin was involved in the active movement of OEE and HERS. The results will contribute to understand the HERS formation mechanism and elucidate the cause of anomaly root. © 2012 John Wiley & Sons A/S.

Control of Oriented Tissue Growth through Repression of Organ Boundary Genes Promotes Stem Morphogenesis.

PubMed

Bencivenga, Stefano; Serrano-Mislata, Antonio; Bush, Max; Fox, Samantha; Sablowski, Robert

2016-10-24

The origin of the stem is a major but poorly understood aspect of plant development, partly because the stem initiates in a relatively inaccessible region of the shoot apical meristem called the rib zone (RZ). We developed quantitative 3D image analysis and clonal analysis tools, which revealed that the Arabidopsis homeodomain protein REPLUMLESS (RPL) establishes distinct patterns of oriented cell division and growth in the central and peripheral regions of the RZ. A genome-wide screen for target genes connected RPL directly to many of the key shoot development pathways, including the development of organ boundaries; accordingly, mutation of the organ boundary gene LIGHT-SENSITIVE HYPOCOTYL 4 restored RZ function and stem growth in the rpl mutant. Our work opens the way to study a developmental process of importance to crop improvement and highlights how apparently simple changes in 3D organ growth can reflect more complex internal changes in oriented cell activities. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Inducible repression of multiple expansin genes leads to growth suppression during leaf development.

PubMed

Goh, Hoe-Han; Sloan, Jennifer; Dorca-Fornell, Carmen; Fleming, Andrew

2012-08-01

Expansins are cell wall proteins implicated in the control of plant growth via loosening of the extracellular matrix. They are encoded by a large gene family, and data linked to loss of single gene function to support a role of expansins in leaf growth remain limited. Here, we provide a quantitative growth analysis of transgenics containing an inducible artificial microRNA construct designed to down-regulate the expression of a number of expansin genes that an expression analysis indicated are expressed during the development of Arabidopsis (Arabidopsis thaliana) leaf 6. The results support the hypothesis that expansins are required for leaf growth and show that decreased expansin gene expression leads to a more marked repression of growth during the later stage of leaf development. In addition, a histological analysis of leaves in which expansin gene expression was suppressed indicates that, despite smaller leaves, mean cell size was increased. These data provide functional evidence for a role of expansins in leaf growth, indicate the importance of tissue/organ developmental context for the outcome of altered expansin gene expression, and highlight the separation of the outcome of expansin gene expression at the cellular and organ levels.

Evaluation of the plant growth-promoting activity of Pseudomonas nitroreducens in Arabidopsis thaliana and Lactuca sativa.

PubMed

Trinh, Cao Son; Lee, Hyeri; Lee, Won Je; Lee, Seok Jin; Chung, Namhyun; Han, Juhyeong; Kim, Jongyun; Hong, Suk-Whan; Lee, Hojoung

2018-06-01

Pseudomonas nitroreducens: strain IHB B 13561 (PnIHB) enhances the growth of Arabidopsis thaliana and Lactuca sativa via the stimulation of cell development and nitrate absorption. Plant growth-promoting rhizobacteria (PGPR) enhance plant development through various mechanisms; they improve the uptake of soil resources by plants to greatly promote plant growth. Here, we used Arabidopsis thaliana seedlings and Lactuca sativa to screen the growth enhancement activities of a purified PGPR, Pseudomonas nitroreducens strain IHB B 13561 (PnIHB). When cocultivated with PnIHB, both species of plants exhibited notably improved growth, particularly in regard to biomass. Quantitative reverse transcription polymerase chain reaction analysis indicated high expression levels of the nitrate transporter genes, especially NRT2.1, which plays a major role in the high-affinity nitrate transport system in roots. Moreover, enhanced activity of the cyclin-B1 promoter was observed when wild-type 'Columbia-0' Arabidopsis seedlings were exposed to PnIHB, whereas upregulation of cyclin-B also occurred in the inoculated lettuce seedlings. Overall, these results suggest that PnIHB improves A. thaliana and L. sativa growth via specific pathways involved in the promotion of cell development and enhancement of nitrate uptake.

Monolithic Perovskite Silicon Tandem Solar Cells with Advanced Optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldschmidt, Jan C.; Bett, Alexander J.; Bivour, Martin

2016-11-14

For high efficiency monolithic perovskite silicon tandem solar cells, we develop low-temperature processes for the perovskite top cell, rear-side light trapping, optimized perovskite growth, transparent contacts and adapted characterization methods.

Serum-free media formulations are cell line-specific and require optimization for microcarrier culture.

PubMed

Tan, Kah Yong; Teo, Kim Leng; Lim, Jessica F Y; Chen, Allen K L; Choolani, Mahesh; Reuveny, Shaul; Chan, Jerry; Oh, Steve Kw

2015-08-01

Mesenchymal stromal cells (MSCs) are being investigated as potential cell therapies for many different indications. Current methods of production rely on traditional monolayer culture on tissue-culture plastic, usually with the use of serum-supplemented growth media. However, the monolayer culturing system has scale-up limitations and may not meet the projected hundreds of billions to trillions batches of cells needed for therapy. Furthermore, serum-free medium offers several advantages over serum-supplemented medium, which may have supply and contaminant issues, leading to many serum-free medium formulations being developed. We cultured seven MSC lines in six different serum-free media and compared their growth between monolayer and microcarrier culture. We show that (i) expansion levels of MSCs in serum-free monolayer cultures may not correlate with expansion in serum-containing media; (ii) optimal culture conditions (serum-free media for monolayer or microcarrier culture) differ for each cell line; (iii) growth in static microcarrier culture does not correlate with growth in stirred spinner culture; (iv) and that early cell attachment and spreading onto microcarriers does not necessarily predict efficiency of cell expansion in agitated microcarrier culture. Current serum-free media developed for monolayer cultures of MSCs may not support MSC proliferation in microcarrier cultures. Further optimization in medium composition will be required for microcarrier suspension culture for each cell line. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Cell culture media impact on drug product solution stability.

PubMed

Purdie, Jennifer L; Kowle, Ronald L; Langland, Amie L; Patel, Chetan N; Ouyang, Anli; Olson, Donald J

2016-07-08

To enable subcutaneous administration of monoclonal antibodies, drug product solutions are often needed at high concentrations. A significant risk associated with high drug product concentrations is an increase in aggregate level over the shelf-life dating period. While much work has been done to understand the impact of drug product formulation on aggregation, there is limited understanding of the link between cell culture process conditions and soluble aggregate growth in drug product. During cell culture process development, soluble aggregates are often measured at harvest using cell-free material purified by Protein A chromatography. In the work reported here, cell culture media components were evaluated with respect to their impact on aggregate levels in high concentration solution drug product during accelerated stability studies. Two components, cysteine and ferric ammonium citrate, were found to impact aggregate growth rates in our current media (version 1) leading to the development of new chemically defined media and concentrated feed formulations. The new version of media and associated concentrated feeds (version 2) were evaluated across four cell lines producing recombinant IgG4 monoclonal antibodies and a bispecific antibody. In all four cell lines, the version 2 media reduced aggregate growth over the course of a 12 week accelerated stability study compared with the version 1 media, although the degree to which aggregate growth decreased was cell line dependent. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:998-1008, 2016. © 2016 American Institute of Chemical Engineers.

Effect of lag time distribution on the lag phase of bacterial growth - a Monte Carlo analysis

USDA-ARS?s Scientific Manuscript database

The objective of this study is to use Monte Carlo simulation to evaluate the effect of lag time distribution of individual bacterial cells incubated under isothermal conditions on the development of lag phase. The growth of bacterial cells of the same initial concentration and mean lag phase durati...

The prisoner's dilemma as a cancer model.

PubMed

West, Jeffrey; Hasnain, Zaki; Mason, Jeremy; Newton, Paul K

2016-09-01

Tumor development is an evolutionary process in which a heterogeneous population of cells with different growth capabilities compete for resources in order to gain a proliferative advantage. What are the minimal ingredients needed to recreate some of the emergent features of such a developing complex ecosystem? What is a tumor doing before we can detect it? We outline a mathematical model, driven by a stochastic Moran process, in which cancer cells and healthy cells compete for dominance in the population. Each are assigned payoffs according to a Prisoner's Dilemma evolutionary game where the healthy cells are the cooperators and the cancer cells are the defectors. With point mutational dynamics, heredity, and a fitness landscape controlling birth and death rates, natural selection acts on the cell population and simulated 'cancer-like' features emerge, such as Gompertzian tumor growth driven by heterogeneity, the log-kill law which (linearly) relates therapeutic dose density to the (log) probability of cancer cell survival, and the Norton-Simon hypothesis which (linearly) relates tumor regression rates to tumor growth rates. We highlight the utility, clarity, and power that such models provide, despite (and because of) their simplicity and built-in assumptions.

SU-E-T-751: Three-Component Kinetic Model of Tumor Growth and Radiation Response for Stereotactic Radiosurgery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watanabe, Y; Dahlman, E; Leder, K

Purpose: To develop and study a kinetic model of tumor growth and its response to stereotactic radiosurgery (SRS) by assuming that the cells in irradiated tumor volume were made of three types. Methods: A set of ordinary differential equations (ODEs) were derived for three types of cells and a tumor growth rate. It is assumed that the cells were composed of actively proliferating cells, lethally damaged-dividing cells, and non-dividing cells. We modeled the tumor volume growth with a time-dependent growth rate to simulate the saturation of growth. After SRS, the proliferating cells were permanently damaged and converted to the lethallymore » damaged cells. The amount of damaged cells were estimated by the LQ-model. The damaged cells gradually stopped dividing/proliferating and died with a constant rate. The dead cells were cleared from their original location with a constant rate. The total tumor volume was the sum of the three components. The ODEs were numerically solved with appropriate initial conditions for a given dosage. The proposed model was used to model an animal experiment, for which the temporal change of a rhabdomyosarcoma tumor volume grown in a rat was measured with time resolution sufficient to test the model. Results: To fit the model to the experimental data, the following characteristics were needed with the model parameters. The α-value in the LQ-model was smaller than the commonly used value; furthermore, it decreased with increasing dose. At the same time, the tumor growth rate after SRS had to increase. Conclusions: The new 3-component model of tumor could simulate the experimental data very well. The current study suggested that the radiation sensitivity and the growth rate of the proliferating tumor cells may change after irradiation and it depended on the dosage used for SRS. These preliminary observations must be confirmed by future animal experiments.« less

Insulin-like growth factor-1 signaling in renal cell carcinoma.

PubMed

Tracz, Adam F; Szczylik, Cezary; Porta, Camillo; Czarnecka, Anna M

2016-07-12

Renal cell carcinoma (RCC) incidence is highest in highly developed countries and it is the seventh most common neoplasm diagnosed. RCC management include nephrectomy and targeted therapies. Type 1 insulin-like growth factor (IGF-1) pathway plays an important role in cell proliferation and apoptosis resistance. IGF-1 and insulin share overlapping downstream signaling pathways in normal and cancer cells. IGF-1 receptor (IGF1R) stimulation may promote malignant transformation promoting cell proliferation, dedifferentiation and inhibiting apoptosis. Clear cell renal cell carcinoma (ccRCC) patients with IGF1R overexpression have 70 % increased risk of death compared to patients who had tumors without IGF1R expression. IGF1R signaling deregulation may results in p53, WT, BRCA1, VHL loss of function. RCC cells with high expression of IGF1R are more resistant to chemotherapy than cells with low expression. Silencing of IGF1R increase the chemosensitivity of ccRCC cells and the effect is greater in VHL mutated cells. Understanding the role of IGF-1 signaling pathway in RCC may result in development of new targeted therapeutic interventions. First preclinical attempts with anti-IGF-1R monoclonal antibodies or fragment antigen-binding (Fab) fragments alone or in combination with an mTOR inhibitor were shown to inhibit in vitro growth and reduced the number of colonies formed by of RCC cells.

The influence of matrix properties on growth and morphogenesis of human pancreatic ductal epithelial cells in 3D

PubMed Central

Raza, Asad; Ki, Chang Seok; Lin, Chien-Chi

2013-01-01

A highly tunable synthetic biomimetic hydrogel platform was developed to study the growth and morphogenesis of pancreatic ductal epithelial cells (PDEC) under the influence of a myriad of instructive cues. A PDEC line, PANC-1, was used as a model system to illustrate the importance of matrix compositions on cell fate determination. PANC-1 is an immortalized ductal epithelial cell line widely used in the study of pancreatic tumor cell behaviors. PANC-1 cells are also increasingly explored as a potential cell source for endocrine differentiation. Thus far, most studies related to PANC-1, among other PDEC lines, are performed on 2D culture surfaces. Here, we evaluated the effect of matrix compositions on PANC-1 cell growth and morphogenesis in 3D. Specifically, PANC-1 cells were encapsulated in PEG-based hydrogels prepared by step-growth thiol-ene photopolymerization. It was found that thiol-ene hydrogels provided a cytocompatible environment for encapsulation and 3D culture of PANC-1 cells. In contrast to a monolayer morphology on 2D culture surfaces, PANC-1 cells formed clusters in 3D thiol-ene hydrogels within 4 days of culture. After culturing for 10 days, however, the growth and structures of these clusters were significantly impacted by gel matrix properties, including sensitivity of the matrix to proteases, stiffness of the matrix, and ECM-mimetic motifs. The use of matrix metalloproteinase (MMP) sensitive linker or the immobilization of fibronectin-derived RGDS ligand in the matrix promoted PANC-1 cell growth and encouraged them to adopt ductal cyst-like structures. On the other hand, the encapsulated cells formed smaller and more compact aggregates in non-MMP responsive gels. The incorporation of laminin-derived YIGSR peptide did not enhance cell growth and caused the cells to form compact aggregates. Immobilized YIGSR also enhanced the expression of epithelial cell markers including β-catenin and E-cadherin. These studies have established PEG-peptide hydrogels formed by thiol-ene photo-click reaction as a suitable platform for studying and manipulating pancreatic epithelial cell growth and morphogenesis in 3D. PMID:23602364

Target of rapamycin signaling orchestrates growth-defense trade-offs in plants.

PubMed

De Vleesschauwer, David; Filipe, Osvaldo; Hoffman, Gena; Seifi, Hamed Soren; Haeck, Ashley; Canlas, Patrick; Van Bockhaven, Jonas; De Waele, Evelien; Demeestere, Kristof; Ronald, Pamela; Hofte, Monica

2018-01-01

Plant defense to microbial pathogens is often accompanied by significant growth inhibition. How plants merge immune system function with normal growth and development is still poorly understood. Here, we investigated the role of target of rapamycin (TOR), an evolutionary conserved serine/threonine kinase, in the plant defense response. We used rice as a model system and applied a combination of chemical, genetic, genomic and cell-based analyses. We demonstrate that ectopic expression of TOR and Raptor (regulatory-associated protein of mTOR), a protein previously demonstrated to interact with TOR in Arabidopsis, positively regulates growth and development in rice. Transcriptome analysis of rice cells treated with the TOR-specific inhibitor rapamycin revealed that TOR not only dictates transcriptional reprogramming of extensive gene sets involved in central and secondary metabolism, cell cycle and transcription, but also suppresses many defense-related genes. TOR overexpression lines displayed increased susceptibility to both bacterial and fungal pathogens, whereas plants with reduced TOR signaling displayed enhanced resistance. Finally, we found that TOR antagonizes the action of the classic defense hormones salicylic acid and jasmonic acid. Together, these results indicate that TOR acts as a molecular switch for the activation of cell proliferation and plant growth at the expense of cellular immunity. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Morphologic differentiation of colon carcinoma cell lines HT-29 and HT-29KM in rotating-wall vessels

NASA Technical Reports Server (NTRS)

Goodwin, T. J.; Jessup, J. M.; Wolf, D. A.

1992-01-01

A new low shear stress microcarrier culture system has been developed at NASA's Johnson Space Center that permits three-dimensional tissue culture. Two established human colon adenocarcinoma cell lines, HT-29, an undifferentiated, and HT-29KM, a stable, moderately differentiated subline of HT-29, were grown in new tissue culture bioreactors called Rotating-Wall Vessels (RWVs). RWVs are used in conjunction with multicellular cocultivation to develop a unique in vitro tissue modeling system. Cells were cultivated on Cytodex-3 microcarrier beads, with and without mixed normal human colonic fibroblasts, which served as the mesenchymal layer. Culture of the tumor lines in the absence of fibroblasts produced spheroidlike growth and minimal differentiation. In contrast, when tumor lines were co-cultivated with normal colonic fibroblasts, initial growth was confined to the fibroblast population until the microcarriers were covered. The tumor cells then commenced proliferation at an accelerated rate, organizing themselves into three-dimensional tissue masses that achieved 1.0- to 1.5-cm diameters. The masses displayed glandular structures, apical and internal glandular microvilli, tight intercellular junctions, desmosomes, cellular polarity, sinusoid development, internalized mucin, and structural organization akin to normal colon crypt development. Differentiated samples were subjected to transmission and scanning electron microscopy and histologic analysis, revealing embryoniclike mesenchymal cells lining the areas around the growth matrices. Necrosis was minimal throughout the tissue masses. These data suggest that the RWV affords a new model for investigation and isolation of growth, regulatory, and structural processes within neoplastic and normal tissue.

Combination of anti-L1 cell adhesion molecule antibody and gemcitabine or cisplatin improves the therapeutic response of intrahepatic cholangiocarcinoma.

PubMed

Cho, Seulki; Lee, Tae Sup; Song, In Ho; Kim, A-Ram; Lee, Yoon-Jin; Kim, Haejung; Hwang, Haein; Jeong, Mun Sik; Kang, Seung Goo; Hong, Hyo Jeong

2017-01-01

Cholangiocarcinoma has a poor prognosis and is refractory to conventional chemotherapy and radiation therapy. Improving survival of patients with advanced cholangiocarcinoma urgently requires the development of new effective targeted therapies in combination with chemotherapy. We previously developed a human monoclonal antibody (mAb) Ab417 that binds to both the human and mouse L1 cell adhesion molecule (L1CAM) with high affinities. In the present study, we observed that Ab417 exhibited tumor targeting ability in biodistribution studies and dose-dependent tumor growth inhibition in an intrahepatic cholangiocarcinoma (Choi-CK) xenograft mouse model. Regarding the mechanism of action, Ab417 was internalized into the tumor cells and thereby down-regulated membrane L1CAM, and inhibited tumor growth by reducing tumor cell proliferation in vivo. Gemcitabine inhibited the tumor growth in a dose-dependent manner in the Choi-CK xenograft model. However, cisplatin inhibited the tumor growth moderately and not in a dose-dependent way, suggesting that the tumors may have developed resistance to apoptosis induced by cisplatin. Combined treatment with Ab417 and gemcitabine or cisplatin exerted enhanced tumor growth inhibition compared to treatment with antibody or drug alone. The results suggest that Ab417 in combination with chemotherapy may have potential as a new therapeutic regimen for cholangiocarcinoma. Our study is the first to show an enhanced therapeutic effect of a therapeutic antibody targeting L1CAM in combination with chemotherapy in cholangiocarcinoma models.

Unique cell culture systems for ground based research

NASA Technical Reports Server (NTRS)

Lewis, Marian L.

1990-01-01

The horizontally rotating fluid-filled, membrane oxygenated bioreactors developed at NASA Johnson for spacecraft applications provide a powerful tool for ground-based research. Three-dimensional aggregates formed by cells cultured on microcarrier beads are useful for study of cell-cell interactions and tissue development. By comparing electron micrographs of plant seedlings germinated during Shuttle flight 61-C and in an earth-based rotating bioreactor it is shown that some effects of microgravity are mimicked. Bioreactors used in the UAH Bioreactor Laboratory will make it possible to determine some of the effects of altered gravity at the cellular level. Bioreactors can be valuable for performing critical, preliminary-to-spaceflight experiments as well as medical investigations such as in vitro tumor cell growth and chemotherapeutic drug response; the enrichment of stem cells from bone marrow; and the effect of altered gravity on bone and muscle cell growth and function and immune response depression.

Control of root growth and development by reactive oxygen species.

PubMed

Tsukagoshi, Hironaka

2016-02-01

Reactive oxygen species (ROS) are relatively simple molecules that exist within cells growing in aerobic conditions. ROS were originally associated with oxidative stress and seen as highly reactive molecules that are injurious to many cell components. More recently, however, the function of ROS as signal molecules in many plant cellular processes has become more evident. One of the most important functions of ROS is their role as a plant growth regulator. For example, ROS are key molecules in regulating plant root development, and as such, are comparable to plant hormones. In this review, the molecular mechanisms of ROS that are mainly associated with plant root growth are discussed. The molecular links between root growth regulation by ROS and other signals will also be briefly discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Establishment and characterization of a testicular Sertoli cell line from olive flounder Paralichthys olivaceus

NASA Astrophysics Data System (ADS)

Peng, Limin; Zheng, Yuan; You, Feng; Wu, Zhihao; Zou, Yuxia; Zhang, Peijun

2016-09-01

The culture of Sertoli cells has become an indispensable resource in studying spermatogenesis. A new Sertoli cell line (POSC) that consisted predominantly of fibroblast-like cells was derived from the testis of the olive flounder Paralichthys olivaceus and sub-cultured for 48 passages. Analysis of the mtDNA COI gene partial sequence confirmed that the cell line was from P. olivaceus. Cells were optimally maintained at 25°C in DMEM/F12 medium supplemented with fetal bovine serum, basic fibroblast growth factor, and epidermal growth factor. The growth curve of POSC showed a typical "S" shape. Chromosome analysis revealed that the cell line possessed the normal P. olivaceus diploid karyotype of 2n=48t. POSC expressed dmrt1 but not vasa, which was detected using RT-PCR and sequencing. Immunocytochemistry revealed that the cells exhibited the testicular Sertoli cell marker FasL. Therefore, POSC appeared to consist of testicular Sertoli cells. Bright fluorescent signals were observed after the cells were transfected with pEGFP-N3 plasmid, with the transfection efficiency reaching 10%. This research not only offers an ideal model for further gene expression and regulation studies on P. olivaceus, but also serves as valuable material in studying fish spermatogenesis, Sertoli cell-germ cell interactions, and the mechanism of growth and development of testis.

The interaction between RACK1 and WEE1 regulates the growth of gastric cancer cell line HGC27

PubMed Central

Liu, Chao; Ren, Lili; Wang, Yizhao; Liu, Yimeng; Xiao, Jianying

2017-01-01

Receptor of activated C Kinase 1 (RACK1) is an essential scaffold and anchoring protein, which serves an important role in multiple tumorigenesis signaling pathways. The present study aimed to investigate the expression of RACK1 in gastric cancer (GC), and its association with the occurrence and development of GC. In addition, the effect and mechanism of RACK1 overexpression on the growth, and proliferation of GC cells was examined. Firstly, the protein expression of RACK1 was detected in 70 cases of GC tissues and 30 cases of noncancerous tissues using immunohistochemical staining, and the association between clinical and pathological features of GC was analyzed. Secondly, the mRNA and protein expression of RACK1 was determined in the poorly-differentiated human gastric cancer cell line HGC27 and gastric epithelial cell line GES-1. The growth of HGC27 cells following the upregulation of RACK1 was detected using MTT method. Subsequently, the interaction and co-location between RACK1, and WEE1 homolog (S. pombe) (WEE1) in HGC27 cells was confirmed using co-immunoprecipitation and indirect immunofluorescence. The expression level of RACK1 in GC was significantly lower compared with that in pericarcinous tissues (P<0.05). The protein level of RACK1 expression correlated with tumor node metastasis stage, tumor differentiation and lymph node metastasis. The mRNA and protein levels of RACK1 in HGC27 cells were significantly reduced, and overexpressed RACK1 downregulated WEE1 protein expression, thus inhibiting the growth of HGC27 cells. Co-immunoprecipitation and immunofluorescence confirmed that RACK1, and WEE1 interacted and co-located in the cytoplasm of HGC27 cells. Therefore, the abnormal expression of RACK1 in GC tissues was identified to be involved in the occurrence and development of GC. Overexpression of RACK1 was able to inhibit the growth of HGC27 cells. The current study suggests that low expression of RACK1 is an important indicator of poor prognosis of GC. RACK1 and WEE1 interact to regulate the growth of HGC27 cells. PMID:29085480

An endogenous inhibitor of angiogenesis derived from a transitional cell carcinoma: clipped beta2-glycoprotein-I.

PubMed

Beecken, Wolf-Dietrich C; Engl, Tobias; Ringel, Eva M; Camphausen, Kevin; Michaelis, Martin; Jonas, Dietger; Folkman, Judah; Shing, Yuen; Blaheta, Roman A

2006-09-01

Invasive cell carcinoma of the bladder often develops after complete transurethral excision of superficial transitional cell carcinoma. It has been postulated that primary tumors release angiogenesis-blocking proteins which suppress distant metastases. We have identified an endogenous protein which might be responsible for tumor dormancy. A transitional cell carcinoma cell line was developed (UMUC-3i) which inhibits the growth of a tumor implant at a distant site in SCID mice. Conditioned media of UMUC-3i cultured cells was first pooled and then fractioned, and the capacity of individual components to block endothelial cell growth was tested. The protein fraction responsible for blocking endothelial cell growth was identified by N-terminal amino acid sequencing as well as by mass-spectrometry. The effects of the purified protein in preventing endothelial cell proliferation and tube formation in an in vitro angiogenesis assay was investigated. The plasma protein beta(2)-glycoprotein-I (beta(2)gpI) was isolated and identified from conditioned medium of UMUC-3i cultured cells. Based on the in vitro angiogenesis assay, beta(2)gpI strongly inhibited endothelial cell growth and tube formation, whereby the inhibitory activity corresponded to the clipped version of beta(2)gpI (cbeta(2)gpI). Clipping was induced by adding plasmin at a molar ratio 1:15 (plasmin:substrate). Further analysis indicated that cbeta(2)gpI effects were mediated by annexin II surface receptors expressed on endothelial cells. cbeta2gpI may be involved in blocking angiogenic processes and bladder cancer progression. In this case, cbeta2gpI may be a promising tool in bladder cancer therapy.

Identification and characterization of a non-satellite cell muscle resident progenitor during postnatal development.

PubMed

Mitchell, Kathryn J; Pannérec, Alice; Cadot, Bruno; Parlakian, Ara; Besson, Vanessa; Gomes, Edgar R; Marazzi, Giovanna; Sassoon, David A

2010-03-01

Satellite cells are resident myogenic progenitors in postnatal skeletal muscle involved in muscle postnatal growth and adult regenerative capacity. Here, we identify and describe a population of muscle-resident stem cells, which are located in the interstitium, that express the cell stress mediator PW1 but do not express other markers of muscle stem cells such as Pax7. PW1(+)/Pax7(-) interstitial cells (PICs) are myogenic in vitro and efficiently contribute to skeletal muscle regeneration in vivo as well as generating satellite cells and PICs. Whereas Pax7 mutant satellite cells show robust myogenic potential, Pax7 mutant PICs are unable to participate in myogenesis and accumulate during postnatal growth. Furthermore, we found that PICs are not derived from a satellite cell lineage. Taken together, our findings uncover a new and anatomically identifiable population of muscle progenitors and define a key role for Pax7 in a non-satellite cell population during postnatal muscle growth.

BRAF activated non-coding RNA (BANCR) promoting gastric cancer cells proliferation via regulation of NF-κB1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Zhi-Xin; Liu, Zhi-Qiang; Jiang, Biao

Background and objective: Long non-coding RNA, BANCR, has been demonstrated to contribute to the proliferation and migration of tumors. However, its molecular mechanism underlying gastric cancer is still unknown. In present study, we investigated whether BANCR was involved in the development of gastric cancer cells via regulation of NF-κB1. Methods: Human gastric cancer tissues were isolated as well as human gastric cell lines MGC803 and BGC823 were cultured to investigate the role of BANCR in gastric cancer. Results: BANCR expression was significantly up-regulated in gastric tumor tissues and gastric cell lines. Down-regulation of BANCR inhibited gastric cancer cell growth andmore » promoted cell apoptosis, and it also contributed to a significant decrease of NF-κB1 (P50/105) expression and 3′UTR of NF-κB1 activity. Overexpression of NF-κB1 reversed the effect of BANCR on cancer cell growth and apoptosis. MiroRNA-9 (miR-9) targeted NF-κB1, and miR-9 inhibitor also reversed the effects of BANCR on gastric cancer cell growth and apoptosis. Conclusion: BANCR was highly expressed both in gastric tumor tissues and in cancer cells. NF-κB1 and miR-9 were involved in the role of BANCR in gastric cancer cell growth and apoptosis. - Highlights: • BANCR up-regulated in gastric cancer (GC) tissues and cell lines MGC803 and BGC823. • Down-regulation of BANCR inhibited GC cell growth and promoted cell apoptosis. • Down-regulation of BANCR contributed to decreased 3′UTR of NF-κB1 and its expression. • Overexpressed NF-κB1 reversed the effect of BANCR on GC cell growth. • miR-9 inhibitor reversed the effect of BANCR on cancer GC cell growth.« less

Growth-mediated autochemotactic pattern formation in self-propelling bacteria

NASA Astrophysics Data System (ADS)

Mukherjee, Mrinmoy; Ghosh, Pushpita

2018-01-01

Bacteria, while developing a multicellular colony or biofilm, can undergo pattern formation by diverse intricate mechanisms. One such route is directional movement or chemotaxis toward or away from self-secreted or externally employed chemicals. In some bacteria, the self-produced signaling chemicals or autoinducers themselves act as chemoattractants or chemorepellents and thereby regulate the directional movements of the cells in the colony. In addition, bacteria follow a certain growth kinetics which is integrated in the process of colony development. Here, we study the interplay of bacterial growth dynamics, cell motility, and autochemotactic motion with respect to the self-secreted diffusive signaling chemicals in spatial pattern formation. Using a continuum model of motile bacteria, we show growth can act as a crucial tuning parameter in determining the spatiotemporal dynamics of a colony. In action of growth dynamics, while chemoattraction toward autoinducers creates arrested phase separation, pattern transitions and suppression can occur for a fixed chemorepulsive strength.

A drift-diffusion checkpoint model predicts a highly variable and growth-factor-sensitive portion of the cell cycle G1 phase.

PubMed

Jones, Zack W; Leander, Rachel; Quaranta, Vito; Harris, Leonard A; Tyson, Darren R

2018-01-01

Even among isogenic cells, the time to progress through the cell cycle, or the intermitotic time (IMT), is highly variable. This variability has been a topic of research for several decades and numerous mathematical models have been proposed to explain it. Previously, we developed a top-down, stochastic drift-diffusion+threshold (DDT) model of a cell cycle checkpoint and showed that it can accurately describe experimentally-derived IMT distributions [Leander R, Allen EJ, Garbett SP, Tyson DR, Quaranta V. Derivation and experimental comparison of cell-division probability densities. J. Theor. Biol. 2014;358:129-135]. Here, we use the DDT modeling approach for both descriptive and predictive data analysis. We develop a custom numerical method for the reliable maximum likelihood estimation of model parameters in the absence of a priori knowledge about the number of detectable checkpoints. We employ this method to fit different variants of the DDT model (with one, two, and three checkpoints) to IMT data from multiple cell lines under different growth conditions and drug treatments. We find that a two-checkpoint model best describes the data, consistent with the notion that the cell cycle can be broadly separated into two steps: the commitment to divide and the process of cell division. The model predicts one part of the cell cycle to be highly variable and growth factor sensitive while the other is less variable and relatively refractory to growth factor signaling. Using experimental data that separates IMT into G1 vs. S, G2, and M phases, we show that the model-predicted growth-factor-sensitive part of the cell cycle corresponds to a portion of G1, consistent with previous studies suggesting that the commitment step is the primary source of IMT variability. These results demonstrate that a simple stochastic model, with just a handful of parameters, can provide fundamental insights into the biological underpinnings of cell cycle progression.

Plant TOR signaling components

PubMed Central

John, Florian; Roffler, Stefan; Wicker, Thomas; Ringli, Christoph

2011-01-01

Cell growth is a process that needs to be tightly regulated. Cells must be able to sense environmental factors like nutrient abundance, the energy level or stress signals and coordinate growth accordingly. The Target Of Rapamycin (TOR) pathway is a major controller of growth-related processes in all eukaryotes. If environmental conditions are favorable, the TOR pathway promotes cell and organ growth and restrains catabolic processes like autophagy. Rapamycin is a specific inhibitor of the TOR kinase and acts as a potent inhibitor of TOR signaling. As a consequence, interfering with TOR signaling has a strong impact on plant development. This review summarizes the progress in the understanding of the biological significance and the functional analysis of the TOR pathway in plants. PMID:22057328

Existence, functional impairment, and lung repair potential of endothelial colony-forming cells in oxygen-induced arrested alveolar growth.

PubMed

Alphonse, Rajesh S; Vadivel, Arul; Fung, Moses; Shelley, William Chris; Critser, Paul John; Ionescu, Lavinia; O'Reilly, Megan; Ohls, Robin K; McConaghy, Suzanne; Eaton, Farah; Zhong, Shumei; Yoder, Merv; Thébaud, Bernard

2014-05-27

Bronchopulmonary dysplasia and emphysema are life-threatening diseases resulting from impaired alveolar development or alveolar destruction. Both conditions lack effective therapies. Angiogenic growth factors promote alveolar growth and contribute to alveolar maintenance. Endothelial colony-forming cells (ECFCs) represent a subset of circulating and resident endothelial cells capable of self-renewal and de novo vessel formation. We hypothesized that resident ECFCs exist in the developing lung, that they are impaired during arrested alveolar growth in experimental bronchopulmonary dysplasia, and that exogenous ECFCs restore disrupted alveolar growth. Human fetal and neonatal rat lungs contain ECFCs with robust proliferative potential, secondary colony formation on replating, and de novo blood vessel formation in vivo when transplanted into immunodeficient mice. In contrast, human fetal lung ECFCs exposed to hyperoxia in vitro and neonatal rat ECFCs isolated from hyperoxic alveolar growth-arrested rat lungs mimicking bronchopulmonary dysplasia proliferated less, showed decreased clonogenic capacity, and formed fewer capillary-like networks. Intrajugular administration of human cord blood-derived ECFCs after established arrested alveolar growth restored lung function, alveolar and lung vascular growth, and attenuated pulmonary hypertension. Lung ECFC colony- and capillary-like network-forming capabilities were also restored. Low ECFC engraftment and the protective effect of cell-free ECFC-derived conditioned media suggest a paracrine effect. Long-term (10 months) assessment of ECFC therapy showed no adverse effects with persistent improvement in lung structure, exercise capacity, and pulmonary hypertension. Impaired ECFC function may contribute to arrested alveolar growth. Cord blood-derived ECFC therapy may offer new therapeutic options for lung diseases characterized by alveolar damage. © 2014 American Heart Association, Inc.

Umbilical Cord Blood-Derived Mesenchymal Stem Cells Inhibit, But Adipose Tissue-Derived Mesenchymal Stem Cells Promote, Glioblastoma Multiforme Proliferation

PubMed Central

Akimoto, Keiko; Kimura, Kenichi; Nagano, Masumi; Takano, Shingo; To'a Salazar, Georgina; Yamashita, Toshiharu

2013-01-01

Mesenchymal stem cells (MSCs) possess self-renewal and multipotential differentiation abilities, and they are thought to be one of the most reliable stem cell sources for a variety of cell therapies. Recently, cell therapy using MSCs has been studied as a novel therapeutic approach for cancers that show refractory progress and poor prognosis. MSCs from different tissues have different properties. However, the effect of different MSC properties on their application in anticancer therapies has not been thoroughly investigated. In this study, to characterize the anticancer therapeutic application of MSCs from different sources, we established two different kinds of human MSCs: umbilical cord blood-derived MSCs (UCB-MSCs) and adipose-tissue-derived MSCs (AT-MSCs). We used these MSCs in a coculture assay with primary glioblastoma multiforme (GBM) cells to analyze how MSCs from different sources can inhibit GBM growth. We found that UCB-MSCs inhibited GBM growth and caused apoptosis, but AT-MSCs promoted GBM growth. Terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick-end labeling assay clearly demonstrated that UCB-MSCs promoted apoptosis of GBM via tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). TRAIL was expressed more highly by UCB-MSCs than by AT-MSCs. Higher mRNA expression levels of angiogenic factors (vascular endothelial growth factor, angiopoietin 1, platelet-derived growth factor, and insulin-like growth factor) and stromal-derived factor-1 (SDF-1/CXCL12) were observed in AT-MSCs, and highly vascularized tumors were developed when AT-MSCs and GBM were cotransplanted. Importantly, CXCL12 inhibited TRAIL activation of the apoptotic pathway in GBM, suggesting that AT-MSCs may support GBM development in vivo by at least two distinct mechanisms—promoting angiogenesis and inhibiting apoptosis. The opposite effects of AT-MSCs and UCB-MSCs on GBM clearly demonstrate that differences must be considered when choosing a stem cell source for safety in clinical application. PMID:23231075

Involvement of DNA methylation in the control of cell growth during heat stress in tobacco BY-2 cells.

PubMed

Centomani, Isabella; Sgobba, Alessandra; D'Addabbo, Pietro; Dipierro, Nunzio; Paradiso, Annalisa; De Gara, Laura; Dipierro, Silvio; Viggiano, Luigi; de Pinto, Maria Concetta

2015-11-01

The alteration of growth patterns, through the adjustment of cell division and expansion, is a characteristic response of plants to environmental stress. In order to study this response in more depth, the effect of heat stress on growth was investigated in tobacco BY-2 cells. The results indicate that heat stress inhibited cell division, by slowing cell cycle progression. Cells were stopped in the pre-mitotic phases, as shown by the increased expression of CycD3-1 and by the decrease in the NtCycA13, NtCyc29 and CDKB1-1 transcripts. The decrease in cell length and the reduced expression of Nt-EXPA5 indicated that cell expansion was also inhibited. Since DNA methylation plays a key role in controlling gene expression, the possibility that the altered expression of genes involved in the control of cell growth, observed during heat stress, could be due to changes in the methylation state of their promoters was investigated. The results show that the altered expression of CycD3-1 and Nt-EXPA5 was consistent with changes in the methylation state of the upstream region of these genes. These results suggest that DNA methylation, controlling the expression of genes involved in plant development, contributes to growth alteration occurring in response to environmental changes.

A physical multifield model predicts the development of volume and structure in the human brain

NASA Astrophysics Data System (ADS)

Rooij, Rijk de; Kuhl, Ellen

2018-03-01

The prenatal development of the human brain is characterized by a rapid increase in brain volume and a development of a highly folded cortex. At the cellular level, these events are enabled by symmetric and asymmetric cell division in the ventricular regions of the brain followed by an outwards cell migration towards the peripheral regions. The role of mechanics during brain development has been suggested and acknowledged in past decades, but remains insufficiently understood. Here we propose a mechanistic model that couples cell division, cell migration, and brain volume growth to accurately model the developing brain between weeks 10 and 29 of gestation. Our model accurately predicts a 160-fold volume increase from 1.5 cm3 at week 10 to 235 cm3 at week 29 of gestation. In agreement with human brain development, the cortex begins to form around week 22 and accounts for about 30% of the total brain volume at week 29. Our results show that cell division and coupling between cell density and volume growth are essential to accurately model brain volume development, whereas cell migration and diffusion contribute mainly to the development of the cortex. We demonstrate that complex folding patterns, including sinusoidal folds and creases, emerge naturally as the cortex develops, even for low stiffness contrasts between the cortex and subcortex.

Normal human mammary epithelial cells spontaneously escape senescence and acquire genomic changes

NASA Technical Reports Server (NTRS)

Romanov, S. R.; Kozakiewicz, B. K.; Holst, C. R.; Stampfer, M. R.; Haupt, L. M.; Tlsty, T. D.

2001-01-01

Senescence and genomic integrity are thought to be important barriers in the development of malignant lesions. Human fibroblasts undergo a limited number of cell divisions before entering an irreversible arrest, called senescence. Here we show that human mammary epithelial cells (HMECs) do not conform to this paradigm of senescence. In contrast to fibroblasts, HMECs exhibit an initial growth phase that is followed by a transient growth plateau (termed selection or M0; refs 3-5), from which proliferative cells emerge to undergo further population doublings (approximately 20-70), before entering a second growth plateau (previously termed senescence or M1; refs 4-6). We find that the first growth plateau exhibits characteristics of senescence but is not an insurmountable barrier to further growth. HMECs emerge from senescence, exhibit eroding telomeric sequences and ultimately enter telomere-based crisis to generate the types of chromosomal abnormalities seen in the earliest lesions of breast cancer. Growth past senescent barriers may be a pivotal event in the earliest steps of carcinogenesis, providing many genetic changes that predicate oncogenic evolution. The differences between epithelial cells and fibroblasts provide new insights into the mechanistic basis of neoplastic transformation.

Temporal Control of Plant Organ Growth by TCP Transcription Factors.

PubMed

Huang, Tengbo; Irish, Vivian F

2015-06-29

The Arabidopsis petal is a simple laminar organ whose development is largely impervious to environmental effects, making it an excellent model for dissecting the regulation of cell-cycle progression and post-mitotic cell expansion that together sculpt organ form. Arabidopsis petals grow via basipetal waves of cell division, followed by a phase of cell expansion. RABBIT EARS (RBE) encodes a C2H2 zinc finger transcriptional repressor and is required for petal development. During the early phase of petal initiation, RBE regulates a microRNA164-dependent pathway that controls cell proliferation at the petal primordium boundaries. The effects of rbe mutations on petal lamina growth suggest that RBE is also required to regulate later developmental events during petal organogenesis. Here, we demonstrate that, early in petal development, RBE represses the transcription of a suite of CIN-TCP genes that in turn act to inhibit the number and duration of cell divisions; the temporal alleviation of that repression results in the transition from cell division to post-mitotic cell expansion and concomitant petal maturation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Early Development in Fern Gametophytes: Interpreting the Transition to Prothallial Architecture in Terms of Coordinated Photosynthate Production and Osmotic Ion Uptake

PubMed Central

RACUSEN, RICHARD H.

2002-01-01

Gametophytes of Onoclea sensiblis L. were grown under various light and media‐ion conditions to gain a better understanding of the source/sink relationships between photosynthetic and ion‐absorbing cells. There was a clear interdependency between green cell and rhizoid functions, such that the growth and development of the rhizoids was completely dependent on the internal delivery of photosynthates from green cells, and conversion of the one‐dimensional filament into the two‐dimensional prothallus required monovalent cations that could only be provided by rhizoid uptake. The need for monovalent cations was related to osmotic demands of dividing and expanding cells; prothallial development was blocked by monovalent cation deficiency, and the system resorted to Na+ uptake to support cell expansion when K+ was absent. Surgical excisions of filament cells further demonstrated the high degree of coordinated growth between the light‐absorbing and ion‐absorbing regions. It was also learned that excised sub‐apical cells of the protonemata, like the intensively studied apical cell, were capable of remodelling remnants of the filament into a normal prothallus. PMID:12099354

Peroxisome proliferator-activated receptor gamma and transforming growth factor-beta pathways inhibit intestinal epithelial cell growth by regulating levels of TSC-22.

PubMed

Gupta, Rajnish A; Sarraf, Pasha; Brockman, Jeffrey A; Shappell, Scott B; Raftery, Laurel A; Willson, Timothy M; DuBois, Raymond N

2003-02-28

Peroxisome proliferator-activated receptor gamma (PPARgamma) and transforming growth factor-beta (TGF-beta) are key regulators of epithelial cell biology. However, the molecular mechanisms by which either pathway induces growth inhibition and differentiation are incompletely understood. We have identified transforming growth factor-simulated clone-22 (TSC-22) as a target gene of both pathways in intestinal epithelial cells. TSC-22 is member of a family of leucine zipper containing transcription factors with repressor activity. Although little is known regarding its function in mammals, the Drosophila homolog of TSC-22, bunched, plays an essential role in fly development. The ability of PPARgamma to induce TSC-22 was not dependent on an intact TGF-beta1 signaling pathway and was specific for the gamma isoform. Localization studies revealed that TSC-22 mRNA is enriched in the postmitotic epithelial compartment of the normal human colon. Cells transfected with wild-type TSC-22 exhibited reduced growth rates and increased levels of p21 compared with vector-transfected cells. Furthermore, transfection with a dominant negative TSC-22 in which both repressor domains were deleted was able to reverse the p21 induction and growth inhibition caused by activation of either the PPARgamma or TGF-beta pathways. These results place TSC-22 as an important downstream component of PPARgamma and TGF-beta signaling during intestinal epithelial cell differentiation.

Insulin-like growth factor-I receptor activity is essential for Kaposi's sarcoma growth and survival.

PubMed

Catrina, S-B; Lewitt, M; Massambu, C; Dricu, A; Grünler, J; Axelson, M; Biberfeld, P; Brismar, K

2005-04-25

Kaposi's sarcoma (KS) is a highly vascular tumour and is the most common neoplasm associated with human immunodeficiency virus (HIV-1) infection. Growth factors, in particular vascular endothelial growth factor (VEGF), have been shown to play an important role in its development. The role of insulin-like growth factors (IGFs) in the pathophysiology of different tumours led us to evaluate the role of IGF system in KS. The IGF-I receptors (IGF-IR) were identified by immunohistochemistry in biopsies taken from patients with different AIDS/HIV-related KS stages and on KSIMM cells (an established KS-derived cell line). Insulin-like growth factor-I is a growth factor for KSIMM cells with a maximum increase of 3H-thymidine incorporation of 130 +/- 27.6% (P < 0.05) similar to that induced by VEGF and with which it is additive (281 +/- 13%) (P < 0.05). Moreover, specific blockade of the receptor (either by alpha IR3 antibody or by picropodophyllin, a recently described selective IGF-IR tyrosine phosphorylation inhibitor) induced KSIMM apoptosis, suggesting that IGF-IR agonists (IGF-I and -II) mediate antiapoptotic signals for these cells. We were able to identify an autocrine loop essential for KSIMM cell survival in which IGF-II is the IGF-IR agonist secreted by the cells. In conclusion, IGF-I pathway inhibition is a promising therapeutical approach for KS tumours.

Lack of synchronization between iron uptake and cell growth leads to iron overload in Saccharomyces cerevisiae during post-exponential growth modes

PubMed Central

Park, Jinkyu; McCormick, Sean P.; Chakrabarti, Mrinmoy; Lindahl, Paul A.

2014-01-01

Fermenting cells growing exponentially on rich (YPAD) medium transitioned to a slow-growing state as glucose levels declined and their metabolism shifted to respiration. During exponential growth, Fe import and cell growth rates were matched, affording an approximately invariant cellular Fe concentration. During the transitionary period, the high-affinity Fe import rate declined slower than the cell growth rate declined, causing Fe to accumulate, initially as FeIII oxyhydroxide nanoparticles but eventually as mitochondrial and vacuolar Fe. Once in slow-growth mode, Fe import and cell growth rates were again matched, and the cellular Fe concentration was again approximately invariant. Fermenting cells grown on minimal medium (MM) grew more slowly during exponential phase and transitioned to a true stationary state as glucose levels declined. The Fe concentration of MM cells that just entered stationary state was similar to that of YPAD cells, but MM cells continued to accumulate Fe in stationary state. Fe initially accumulated as nanoparticles and high-spin FeII species, but vacuolar FeIII also eventually accumulated. Surprisingly, Fe-packed 5-day-old MM cells suffered no more ROS damage than younger cells, suggesting that Fe concentration alone does not accurately predict the extent of ROS damage. The mode and rate of growth at the time of harvesting dramatically affected cellular Fe content. A mathematical model of Fe metabolism in a growing cell was developed. The model included Fe import via a regulated high-affinity pathway and an unregulated low-affinity pathway. Fe import from the cytosol into vacuoles and mitochondria, and nanoparticle formation were also included. The model captured essential trafficking behavior, demonstrating that cells regulate Fe import in accordance with their overall growth rate and that they misregulate Fe import when nanoparticles accumulate. The lack of regulation of Fe in yeast is perhaps unique compared to the tight regulation of other cellular metabolites. This phenomenon likely derives from the unique chemistry associated with Fe nanoparticle formation. PMID:24344915

Ethanol-induced impairment of polyamine homeostasis – A potential cause of neural tube defect and intrauterine growth restriction in fetal alcohol syndrome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haghighi Poodeh, Saeid, E-mail: saeid.haghighi@oulu.fi; Medical Research Center, Oulu University Hospital, Oulu; Alhonen, Leena

Highlights: • Polyamine pools in embryonic and extraembryonic tissues are developmentally regulated. • Alcohol administration perturbs polyamine levels in the tissues with various patterns. • Total absence of polyamines in the embryo head at 9.5 dpc is critical for development. • The deficiency is associated with reduction in endothelial cell sprouting in the head. • Retarded migration of neural crest cells may cause development of neural tube defect. - Abstract: Introduction: Polyamines play a fundamental role during embryogenesis by regulating cell growth and proliferation and by interacting with RNA, DNA and protein. The polyamine pools are regulated by metabolism andmore » uptake from exogenous sources. The use of certain inhibitors of polyamine synthesis causes similar defects to those seen in alcohol exposure e.g. retarded embryo growth and endothelial cell sprouting. Methods: CD-1 mice received two intraperitoneal injections of 3 g/kg ethanol at 4 h intervals 8.75 days post coitum (dpc). The fetal head, trunk, yolk sac and placenta were collected at 9.5 and 12.5 dpc and polyamine concentrations were determined. Results: No measurable quantity of polyamines could be detected in the embryo head at 9.5 dpc, 12 h after ethanol exposure. Putrescine was not detectable in the trunk of the embryo at that time, whereas polyamines in yolk sac and placenta were at control level. Polyamine deficiency was associated with slow cell growth, reduction in endothelial cell sprouting, an altered pattern of blood vessel network formation and consequently retarded migration of neural crest cells and growth restriction. Discussion: Our results indicate that the polyamine pools in embryonic and extraembryonic tissues are developmentally regulated. Alcohol administration, at the critical stage, perturbs polyamine levels with various patterns, depending on the tissue and its developmental stage. The total absence of polyamines in the embryo head at 9.5 dpc may explain why this stage is so vulnerable to the development of neural tube defect, and growth restriction, the findings previously observed in fetal alcohol syndrome.« less

Stable MOB1 interaction with Hippo/MST is not essential for development and tissue growth control.

PubMed

Kulaberoglu, Yavuz; Lin, Kui; Holder, Maxine; Gai, Zhongchao; Gomez, Marta; Assefa Shifa, Belul; Mavis, Merdiye; Hoa, Lily; Sharif, Ahmad A D; Lujan, Celia; Smith, Ewan St John; Bjedov, Ivana; Tapon, Nicolas; Wu, Geng; Hergovich, Alexander

2017-09-25

The Hippo tumor suppressor pathway is essential for development and tissue growth control, encompassing a core cassette consisting of the Hippo (MST1/2), Warts (LATS1/2), and Tricornered (NDR1/2) kinases together with MOB1 as an important signaling adaptor. However, it remains unclear which regulatory interactions between MOB1 and the different Hippo core kinases coordinate development, tissue growth, and tumor suppression. Here, we report the crystal structure of the MOB1/NDR2 complex and define key MOB1 residues mediating MOB1's differential binding to Hippo core kinases, thereby establishing MOB1 variants with selective loss-of-interaction. By studying these variants in human cancer cells and Drosophila, we uncovered that MOB1/Warts binding is essential for tumor suppression, tissue growth control, and development, while stable MOB1/Hippo binding is dispensable and MOB1/Trc binding alone is insufficient. Collectively, we decrypt molecularly, cell biologically, and genetically the importance of the diverse interactions of Hippo core kinases with the pivotal MOB1 signal transducer.The Hippo tumor suppressor pathway is essential for development and tissue growth control. Here the authors employ a multi-disciplinary approach to characterize the interactions of the three Hippo kinases with the signaling adaptor MOB1 and show how they differently affect development, tissue growth and tumor suppression.

New plant-growth medium for increased power output of the Plant-Microbial Fuel Cell.

PubMed

Helder, M; Strik, D P B T B; Hamelers, H V M; Kuijken, R C P; Buisman, C J N

2012-01-01

In a Plant-Microbial Fuel Cell anode-conditions must be created that are favorable for plant growth and electricity production. One of the major aspects in this is the composition of the plant-growth medium. Hoagland medium has been used until now, with added phosphate buffer to reduce potential losses over the membrane because of differences in pH between anode and cathode. We developed a new, improved plant-growth medium that improves current production, while the plant keeps growing. This medium is a nitrate-less, ammonium-rich medium that contains all macro- and micro-nutrients necessary for plant growth, with a balanced amount of bicarbonate buffer. Sulphate presence in the plant-growth medium helps to keep a low anode-potential. With the new plant-growth medium the maximum current production of the Plant-Microbial Fuel Cell increased from 186 mA/m(2) to 469 mA/m(2). Copyright © 2011 Elsevier Ltd. All rights reserved.

Assessment of Growth Factors Secreted by Human Breastmilk Mesenchymal Stem Cells.

PubMed

Kaingade, Pankaj Mahipatrao; Somasundaram, Indumathi; Nikam, Amar Babaso; Sarang, Shabari Amit; Patel, Jagdish Shantilal

2016-01-01

Human breastmilk is a dynamic, multifaceted biological fluid containing nutrients, bioactive substances, and growth factors. It is effective in supporting growth and development of an infant. As breastmilk has been found to possess mesenchymal stem cells, the importance of the components of breastmilk and their physiological roles is increasing day by day. The present study was intended to identify the secretions of growth factors, mainly vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF), from human breastmilk mesenchymal stem cells under basal conditions of in vitro cell culture using synthetic media and human cord serum. The growth factors were analyzed with the enzyme-linked immunosorbent assay technique. The cultured mesenchymal stem cells of breastmilk without serum revealed significant differences in secretions of the VEGF and HGF growth factors (8.55 ± 2.26402 pg/mL and 230.8 ± 45.9861 pg/mL, respectively) compared with mesenchymal stem cells of breastmilk with serum (21.31 ± 4.69 pg/mL and 2,404.42 ± 481.593 pg/mL, respectively). Results obtained from our study demonstrate that both VEGF and HGF are secreted in vitro by human breastmilk mesenchymal stem cells. The roles of VEGF and HGF in surfactant secretion, pulmonary maturation, and neonatal maturity have been well established. Thus, we emphasize that breastmilk-derived MSCs could be a potent therapeutic source in treating neonatal diseases. Besides, due to its immense potency, the study also emphasizes the importance of breastfeeding, which is promoted by organizations like the World Heatlh Organization and UNICEF.

FGF9, activin and TGFβ promote testicular characteristics in an XX gonad organ culture model.

PubMed

Gustin, Sonja E; Stringer, Jessica M; Hogg, Kirsten; Sinclair, Andrew H; Western, Patrick S

2016-11-01

Testis development is dependent on the key sex-determining factors SRY and SOX9, which activate the essential ligand FGF9. Although FGF9 plays a central role in testis development, it is unable to induce testis formation on its own. However, other growth factors, including activins and TGFβs, also present testis during testis formation. In this study, we investigated the potential of FGF9 combined with activin and TGFβ to induce testis development in cultured XX gonads. Our data demonstrated differing individual and combined abilities of FGF9, activin and TGFβ to promote supporting cell proliferation, Sertoli cell development and male germ line differentiation in cultured XX gonads. FGF9 promoted proliferation of supporting cells in XX foetal gonads at rates similar to those observed in vivo during testis cord formation in XY gonads but was insufficient to initiate testis development. However, when FGF9, activin and TGFβ were combined, aspects of testicular development were induced, including the expression of Sox9, morphological reorganisation of the gonad and deposition of laminin around germ cells. Enhancing β-catenin activity diminished the testis-promoting activities of the combined growth factors. The male promoting activity of FGF9 and the combined growth factors directly or indirectly extended to the germ line, in which a mixed phenotype was observed. FGF9 and the combined growth factors promoted male germ line development, including mitotic arrest, but expression of pluripotency genes was maintained, rather than being repressed. Together, our data provide evidence that combined signalling by FGF9, activin and TGFβ can induce testicular characteristics in XX gonads. © 2016 Society for Reproduction and Fertility.

Silicon-on Ceramic Process: Silicon Sheet Growth and Device Development for the Large-area Silicon Sheet and Cell Development Tasks of the Low-cost Solar Array Project

NASA Technical Reports Server (NTRS)

Chapman, P. W.; Zook, J. D.; Heaps, J. D.; Grung, B. L.; Koepke, B.; Schuldt, S. B.

1979-01-01

The technical and economic feasibility of producing solar cell-quality silicon was investigated. This was done by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. Significant progress in the following areas was demonstrated: (1) fabricating a 10 sq cm cell having 9.9 percent conversion efficiency; (2) producing a 225 sq cm layer of sheet silicon; and (3) obtaining 100 microns thick coatings at pull speed of 0.15 cm/sec, although approximately 50 percent of the layer exhibited dendritic growth.

Peroxisome proliferator-activated receptor-β/δ (PPARβ/δ) ligands inhibit growth of UACC903 and MCF7 human cancer cell lines

PubMed Central

Girroir, Elizabeth E.; Hollingshead, Holly E.; Billin, Andrew N.; Willson, Timothy M.; Robertson, Gavin P.; Sharma, Arun K.; Amin, Shantu; Gonzalez, Frank J.; Peters, Jeffrey M.

2008-01-01

The development of peroxisome proliferator-activated receptor-β/δ (PPARβ/δ) ligands for the treatment of diseases including metabolic syndrome, diabetes and obesity has been hampered due to contradictory findings on their potential safety. For example, while some reports show that ligand activation of PPARβ/δ promotes the induction of terminal differentiation and inhibition of cell growth, other reports suggest that PPARβ/δ ligands potentiate tumorigenesis by increasing cell proliferation. Some of the contradictory findings could be due in part to differences in the ligand examined, the presence or absence of serum in cell cultures, differences in cell lines, or differences in the method used to quantify cell growth. For these reasons, this study examined the effect of ligand activation of PPARβ/δ on cell growth of two human cancer cell lines, MCF7 (breast cancer) and UACC903 (melanoma) in the presence or absence of serum using two highly specific PPARβ/δ ligands, GW0742 or GW501516. Culturing cells in the presence of either GW0742 or GW501516 caused upregulation of the known PPARβ/δ target gene angiopoetin-like protein 4 (ANGPTL4). Inhibition of cell growth was observed in both cell lines cultured in the presence of either GW0742 or GW501516, and the presence or absence of serum had little influence on this inhibition. Results from the present studies demonstrate that ligand activation of PPARβ/δ inhibits the growth of both MCF7 and UACC903 cell lines and provide further evidence that PPARβ/δ ligands are not mitogenic in human cancer cell lines. PMID:18054822

Autogenous cultured growth plate chondrocyte transplantation in the treatment of physeal injury in rabbits.

PubMed

Tomaszewski, R; Bohosiewicz, J; Gap, A; Bursig, H; Wysocka, A

2014-11-01

The aim of this experimental study on New Zealand's white rabbits was to investigate the transplantation of autogenous growth plate cells in order to treat the injured growth plate. They were assessed in terms of measurements of radiological tibial varus and histological characteristics. An experimental model of plate growth medial partial resection of the tibia in 14 New Zealand white rabbits was created. During this surgical procedure the plate growth cells were collected and cultured. While the second surgery was being performed, the autologous cultured growth plate cells were grafted at the right tibia, whereas the left tibia was used as a control group. Histological examinations showed that the grafted right tibia presented the regular shape of the plate growth with hypertrophic maturation, chondrocyte columniation and endochondral calcification. Radiological study shows that the mean tibial deformity at the left angle was 20.29° (6.25 to 33) and 7.21° (5 to 10) in the right angle. This study has demonstrated that grafting of autogenous cultured growth plate cells into a defect of the medial aspect of the proximal tibial physis can prevent bone bridge formation, growth arrest and the development of varus deformity. Cite this article: Bone Joint Res 2014;3:310-16. ©2014 The British Editorial Society of Bone & Joint Surgery.

MITF suppression improves the sensitivity of melanoma cells to a BRAF inhibitor.

PubMed

Aida, Satoshi; Sonobe, Yukiko; Tanimura, Hiromi; Oikawa, Nobuhiro; Yuhki, Munehiro; Sakamoto, Hiroshi; Mizuno, Takakazu

2017-11-28

Microphthalmia-associated transcription factor (MITF) is expressed in melanomas and has a critical role in melanocyte development and transformation. Because inhibition of MITF inhibits cell growth in melanoma, MITF is a potential therapeutic target molecule. Here, we report the identification of CH6868398, which has a novel chemical structure and suppresses MITF expression at the protein level in melanoma cells. CH6868398 showed cell growth inhibition activity against MITF-dependent melanoma cells both with and without BRAF mutation and also exhibited anti-tumor efficacy in a melanoma xenograft model. Because selective BRAF inhibitors are standard therapeutics for BRAF-mutated melanoma, we investigated the effect of CH6868398 with a BRAF inhibitor, PLX4720, on cell growth inhibition. The addition of CH6868398 enhanced the cell growth inhibition activity of PLX4720 in melanoma cell lines. Furthermore, combination of CH6868398 and PLX4720 efficiently suppressed MITF protein and enhanced cleavage of Caspase3 and poly (ADP-ribose) polymerase (PARP) in melanoma cell lines. These data support the therapeutic potential of CH6868398 as an anti-melanoma agent that reduces MITF protein levels in combination with BRAF inhibitors. Copyright © 2017 Elsevier B.V. All rights reserved.

The effect of retinal pigment epithelial cell patch size on growth factor expression

DOE PAGES

Vargis, Elizabeth A.; Peterson, Cristen B.; Morrell-Falvey, Jennifer L.; ...

2014-01-30

The spatial organization of retinal pigment epithelial (RPE) cells grown in culture was controlled using micropatterning techniques in order to examine the effect of patch size on cell health and differentiation. Understanding this effect is a critical step in the development of multiplexed high throughput fluidic assays and provides a model for replicating disease states associated with the deterioration of retinal tissue during age-related macular degeneration (AMD). Microcontact printing of fibronectin on polystyrene and glass substrates was used to promote cell attachment, forming RPE patches of controlled size and shape. These colonies mimic the effect of atrophy and loss-of-function thatmore » occurs in the retina during degenerative diseases such as AMD. After 72 hours of cell growth, levels of vascular endothelial growth factor (VEGF), an important biomarker of AMD, were measured. Cells were counted and morphological indicators of cell viability and tight junction formation were assessed via fluorescence microscopy. As a result, up to a twofold increase of VEGF expression per cell was measured as colony size decreased, suggesting that the local microenvironment of, and connections between, RPE cells influences growth factor expression leading to the initiation and progression of diseases such as AMD.« less

Modification of cytokine-induced killer cells with chimeric antigen receptors (CARs) enhances antitumor immunity to epidermal growth factor receptor (EGFR)-positive malignancies.

PubMed

Ren, Xuequn; Ma, Wanli; Lu, Hong; Yuan, Lei; An, Lei; Wang, Xicai; Cheng, Guanchang; Zuo, Shuguang

2015-12-01

Epidermal growth factor receptor (EGFR, ErbB1, Her-1) is a cell surface molecule overexpressing in a variety of human malignancies and, thus, is an excellent target for immunotherapy. Immunotherapy targeting EGFR-overexpressing malignancies using genetically modified immune effector cells is a novel and promising approach. In the present study, we have developed an adoptive cellular immunotherapy strategy based on the chimeric antigen receptor (CAR)-modified cytokine-induced killer (CAR-CIK) cells specific for the tumor cells expressing EGFR. To generate CAR-CIK cells, a lentiviral vector coding the EGFR-specific CAR was constructed and transduced into the CIK cells. The CAR-CIK cells showed significantly enhanced cytotoxicity and increased production of cytokines IFN-γ and IL-2 when co-cultured with EGFR-positive cancer cells. In tumor xenografts, adoptive immunotherapy of CAR-CIK cells could inhibit tumor growth and prolong the survival of EGFR-overexpressing human tumor xenografts. Moreover, tumor growth inhibition and prolonged survival in mice with EGFR(+) human cancer were associated with the increased persistence of CAR-CIK cells in vivo. Our study indicates that modification with EGFR-specific CAR strongly enhances the antitumor activity of the CIK cells against EGFR-positive malignancies.

Are There Really Animals Like That? No Cell Division.

ERIC Educational Resources Information Center

Blackwelder, R. E.; Garoian, G. S.

1984-01-01

Provides examples of animals in which growth occurs without cell division. Indicates that this phenomenon (called cell constancy or eutely) is an oddity of development that has arisen independently in several animal groups. (JN)

Growth mechanics of bacterial cell wall and morphology of bacteria

NASA Astrophysics Data System (ADS)

Jiang, Hongyuan; Sun, Sean

2010-03-01

The peptidoglycan cell wall of bacteria is responsible for maintaining the cell shape and integrity. During the bacterial life cycle, the growth of the cell wall is affected by mechanical stress and osmotic pressure internal to the cell. We develop a theory to describe cell shape changes under the influence of mechanical forces. We find that the theory predicts a steady state size and shape for bacterial cells ranging from cocci to spirillum. Moreover, the theory suggest a mechanism by which bacterial cytoskeletal proteins such as MreB and crescentin can maintain the shape of the cell. The theory can also explain the several recent experiments on growing bacteria in micro-environments.

The neural cell adhesion molecule promotes FGFR-dependent phosphorylation and membrane targeting of the exocyst complex to induce exocytosis in growth cones.

PubMed

Chernyshova, Yana; Leshchyns'ka, Iryna; Hsu, Shu-Chan; Schachner, Melitta; Sytnyk, Vladimir

2011-03-09

The exocyst complex is an essential regulator of polarized exocytosis involved in morphogenesis of neurons. We show that this complex binds to the intracellular domain of the neural cell adhesion molecule (NCAM). NCAM promotes FGF receptor-mediated phosphorylation of two tyrosine residues in the sec8 subunit of the exocyst complex and is required for efficient recruitment of the exocyst complex to growth cones. NCAM at the surface of growth cones induces Ca(2+)-dependent vesicle exocytosis, which is blocked by an inhibitor of L-type voltage-dependent Ca(2+) channels and tetanus toxin. Preferential exocytosis in growth cones underlying neurite outgrowth is inhibited in NCAM-deficient neurons as well as in neurons transfected with phosphorylation-deficient sec8 and dominant-negative peptides derived from the intracellular domain of NCAM. Thus, we reveal a novel role for a cell adhesion molecule in that it regulates addition of the new membrane to the cell surface of growth cones in developing neurons.

Electron Microscopy of the Infection and Subsequent Development of Soybean Nodule Cells

PubMed Central

Goodchild, D. J.; Bergersen, F. J.

1966-01-01

Goodchild, D. J. (Commonwealth Scientific and Industrial Research Organization, Canberra, Australia), and F. J. Bergersen. Electron microscopy of the infection and subsequent development of soybean nodule cells. J. Bacteriol. 92:204–213. 1966—Electron microscopy of thin sections of the developing central tissue cells of young soybean root nodules has shown that infection is initiated by a few infection threads which penetrate cells of the young central tissue. Extension growth of the threads may be a result of pressure developed from the growth of the bacteria within the threads. Release of bacteria from a thread is preceded by the development on an infection thread of a bulge with a cellulose-free membrane-bounded extension; bacteria move from this into the host cells by an endocytotic process and remain enclosed in an infection vacuole which is bounded by a membrane of host-cell origin. Multiplication of the intracellular bacteria takes place within these vacuoles. Until the host cell becomes filled with bacteria, the vacuoles separate into discrete units at each division. Later, division of the bacteria occurs within each vacuole, thus leading to the mature structure of the central tissue cells in which several bacteria are enclosed within each membrane-bounded unit. Images PMID:5949564

Regulation of cell death and cell survival gene expression during ovarian follicular development and atresia.

PubMed

Jiang, Jin-Yi; Cheung, Carmen K M; Wang, Yifang; Tsang, Benjamin K

2003-01-01

Mammalian ovarian follicular development and atresia is closely regulated by the cross talk of cell death and cell survival signals, which include endocrine hormones (gonadotropins) and intra-ovarian regulators (gonadal steroids, cytokines and growth factors). The fate of the follicle is dependent on a delicate balance in the expression and actions of factors promoting follicular cell proliferation, growth and differentiation and of those inducing programmed cell death (apoptosis). As an important endocrine hormone, FSH binds to its granulosa cell receptors and promotes ovarian follicle survival and growth not only by stimulating proliferation and estradiol secretion of these cells, but also inhibiting the apoptosis by up-regulating the expression of intracellular anti-apoptotic proteins, such as XIAP and FLIP. In addition, intra-ovarian regulators, such as TGF-alpha and TNF-alpha, also play an important role in the control of follicular development and atresia. In response to FSH, Estradiol-17 beta synthesized from the granulosa cells stimulates thecal expression of TGF-alpha, which in turn increases granulosa cell XIAP expression and proliferation. The death receptor and ligand, Fas and Fas ligand, are expressed in granulosa cells following gonadotropin withdrawal, culminating in caspase-mediated apoptosis and follicular atresia. In contrast, TNF-alpha has both survival and pro-apoptotic function in the follicle, depending on the receptor subtype activated, but has been shown to promote granulosa cell survival by increasing XIAP and FLIP expression via the IkappaB-NFkappaB pathway. The pro-apoptotic action of TNF-alpha is mediated through the activation of caspases, via its receptor- (i.e. Caspases-8 and -3) and mitochrondria- (i.e. Caspase-9 and -3) death pathways. In the present manuscript, we have reviewed the actions and interactions of gonadotropins and intra-ovarian regulators in the control of granulosa cell fate and ultimately follicular destiny. We have highlighted the role and regulation of granulosa cell XIAP and FLIP expression, as well as their interactions with the death signaling pathways in the maintenance of granulosa cell survival during follicular development. We have provided strong evidence for these intracellular survival factors as key determinants for ovarian follicular destiny (growth versus atresia), the expression of which is regulated by a highly integrated endocrine, paracrine and autocrine mechanism. Further studies in these aspects will lead to a better understanding of the molecular and cellular regulation of follicular development and atresia, and provide invaluable insight into novel strategies in assisted reproduction in human infertility as well as in increasing reproductive efficiency in livestock industries.

IL-33 promotes growth and liver metastasis of colorectal cancer in mice by remodeling the tumor microenvironment and inducing angiogenesis.

PubMed

Zhang, Yu; Davis, Celestia; Shah, Sapana; Hughes, Daniel; Ryan, James C; Altomare, Diego; Peña, Maria Marjorette O

2017-01-01

Liver metastasis is the major cause of death from colorectal cancer (CRC). Understanding its mechanisms is necessary for timely diagnosis and development of effective therapies. Interleukin-33 (IL-33) is an IL-1 cytokine family member that uniquely functions as a cytokine and nuclear factor. It is released by necrotic epithelial cells and activated innate immune cells, functioning as an alarmin or an early danger signal. Its role in invoking type 2 immune response has been established; however, it has contrasting roles in tumor development and metastasis. We identified IL-33 as a potently upregulated cytokine in a highly metastatic murine CRC cell line and examined its role in tumor growth and metastasis to the liver. IL-33 was transgenically expressed in murine and human adenocarcinoma and carcinoma cell lines and their growth and spontaneous metastasis to the liver were assessed in orthotopic models of CRC in wild-type C57Bl/6 and Il33 knockout mice. The results showed that increased expression of IL-33 in CRC cells enhanced their tumor take, growth, and liver metastasis. Tumor- rather than host-derived IL-33 induced the enhanced recruitment of CD11b + GR1 + and CD11b + F4/80 + myeloid cells to remodel the tumor microenvironment by increased expression of mobilizing cytokines, and tumor angiogenesis by activating endothelial cells. IL-33 expression was elevated in patient tumor tissues, induced early in adenoma development, and activated by pro-inflammatory cytokines derived from the tumor microenvironment. The data suggest that tumor-derived IL-33 modulates the tumor microenvironment to potently promote colon carcinogenesis and liver metastasis, underscoring its potential as a therapeutic target. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Baicalein suppresses the androgen receptor (AR)-mediated prostate cancer progression via inhibiting the AR N-C dimerization and AR-coactivators interaction.

PubMed

Xu, Defeng; Chen, Qiulu; Liu, Yalin; Wen, Xingqiao

2017-12-01

Androgen receptor (AR) plays a critical role in prostate cancer (PCa) development and progression. Androgen deprivation therapy with antiandrogens to reduce androgen biosynthesis or prevent androgens from binding to AR are widely used to suppress AR-mediated PCa growth. However, most of ADT may eventually fail with development of the castration resistance after 12-24 months. Here we found that a natural product baicalein can effectively suppress the PCa progression via targeting the androgen-induced AR transactivation with little effect to AR protein expression. PCa cells including LNCaP, CWR22Rv1, C4-2, PC-3, and DU145, were treated with baicalein and luciferase assay was used to evaluate their effect on the AR transactivation. Cell growth and IC 50 were determined by MTT assay after 48 hrs treatment. RT-PCR was used to evaluate the mRNA levels of AR target genes including PSA, TMPRSS2, and TMEPA1. Western blot was used to determine AR and PSA protein expression. The natural product of baicalein can selectively inhibit AR transactivation with little effect on the other nuclear receptors, including ERα, and GR. At a low concentration, 2.5 μM of baicalein effectively suppresses the growth of AR-positive PCa cells, and has little effect on AR-negative PCa cells. Mechanism dissection suggest that baicalein can suppress AR target genes (PSA, TMPRSS2, and TMEPA1) expression in both androgen responsive LNCaP cells and castration resistant CWR22Rv1 cells, that may involve the inhibiting the AR N/C dimerization and AR-coactivators interaction. Baicalein may be developed as an effective anti-AR therapy via its ability to inhibit AR transactivation and AR-mediated PCa cell growth.

Bioprocess development for the production of mouse-human chimeric anti-epidermal growth factor receptor vIII antibody C12 by suspension culture of recombinant Chinese hamster ovary cells.

PubMed

Hu, Suwen; Deng, Lei; Wang, Huamao; Zhuang, Yingping; Chu, Ju; Zhang, Siliang; Li, Zhonghai; Guo, Meijin

2011-05-01

The mouse-human chimeric anti-epidermal growth factor receptor vIII (EGFRvIII) antibody C12 is a promising candidate for the diagnosis of hepatocellular carcinoma (HCC). In this study, 3 processes were successfully developed to produce C12 by cultivation of recombinant Chinese hamster ovary (CHO-DG44) cells in serum-free medium. The effect of inoculum density was evaluated in batch cultures of shaker flasks to obtain the optimal inoculum density of 5 × 10(5) cells/mL. Then, the basic metabolic characteristics of CHO-C12 cells were studied in stirred bioreactor batch cultures. The results showed that the limiting concentrations of glucose and glutamine were 6 and 1 mM, respectively. The culture process consumed significant amounts of aspartate, glutamate, asparagine, serine, isoleucine, leucine, and lysine. Aspartate, glutamate, asparagine, and serine were particularly exhausted in the early growth stage, thus limiting cell growth and antibody synthesis. Based on these findings, fed-batch and perfusion processes in the bioreactor were successfully developed with a balanced amino acid feed strategy. Fed-batch and especially perfusion culture effectively maintained high cell viability to prolong the culture process. Furthermore, perfusion cultures maximized the efficiency of nutrient utilization; the mean yield coefficient of antibody to consumed glucose was 44.72 mg/g and the mean yield coefficient of glutamine to antibody was 721.40 mg/g. Finally, in small-scale bioreactor culture, the highest total amount of C12 antibody (1,854 mg) was realized in perfusion cultures. Therefore, perfusion culture appears to be the optimal process for small-scale production of C12 antibody by rCHO-C12 cells.

A Mechanobiological model for damage-induced growth in arterial tissue with application to in-stent restenosis

NASA Astrophysics Data System (ADS)

Fereidoonnezhad, B.; Naghdabadi, R.; Sohrabpour, S.; Holzapfel, G. A.

In-stent restenosis (ISR) is one of the main drawbacks of stent implementation which limits the long-term success of the procedure. Morphological changes occurring within the arterial wall due to stent-induced mechanical injury are a major cause for activation of vascular smooth muscle cells (VSMCs), and the subsequent development of ISR. Considering the theory of volumetric mass growth and adopting a multiplicative decomposition of the deformation gradient into an elastic part and a growth part, we present a mechanobiological model for ISR. An evolution equation is developed for mass growth of the neointima, in which the activation of VSMCs due to stent-induced damage (injury) and the proliferation rate of the activated cells are considered. By introducing the mass evolution into the mass balance equation, we obtain the evolution of the growth tensor over time. The model is implemented in a finite element code and the procedure of angioplasty is simulated, whereby the features of the proposed growth model are illustrated.

Balance between fibroblast growth factor 10 and secreted frizzled-relate protein-1 controls the development of hair follicle by competitively regulating β-catenin signaling.

PubMed

Zhang, Haihua; Nan, Weixiao; Wang, Shiyong; Si, Huazhe; Li, Guangyu

2018-07-01

Growth of hairs depends on the regular development of hair follicles which are hypothesized to be regulated by fibroblast growth factor 10 (FGF10) and secreted frizzled-relate protein-1 (sFRP1). In the current study, the effect of FGF10 or sFRP1 on hair follicle cells was assessed and the possible mechanism mediating the interaction between FGF10 and sFRP1 in hair follicle cells was explored. Out root sheath (ORS) and dermal papilla (DP) cells were isolated from mink skin tissues and subjected to administrations of FGF10 (50 ng/ml) or sFRP1 (10 ng/ml). Then proliferation, cell cycle distribution, and migration potentials of both cell types were detected. Moreover, the nuclear translocation of β-catenin was determined. The results showed that the administration of FGF10 increased cell proliferation and migration potential in both cell types, which was associated with the up-regulated nuclear level of β-catenin. To the contrary, the administration of sFRP1 decreased cell proliferation and migration potentials while induced the G1 cell cycle arrest in both cell types by inhibiting nuclear translocation of β-catenin. Compared with the sole administrations, the co-treatment of FGF10 and sFRP1 had a medium effect on cell proliferation, cell cycle distribution, cell migration, and nuclear β-catenin level, representing an antagonistic interaction between the two factors, which was exerted by competitively regulating β-catenin pathway. Conclusively, the cycle of hair follicles was promoted by FGF10 while blocked by sFRP1 and the interplay between the two factors controlled the development of hair follicles by competitively regulating β-catenin signaling. Copyright © 2018. Published by Elsevier Masson SAS.

Selective growth inhibition of human breast cancer cells by graviola fruit extract in vitro and in vivo involving downregulation of EGFR expression.

PubMed

Dai, Yumin; Hogan, Shelly; Schmelz, Eva M; Ju, Young H; Canning, Corene; Zhou, Kequan

2011-01-01

The epidermal growth factor receptor (EGFR) is an oncogene frequently overexpressed in breast cancer (BC), and its overexpression has been associated with poor prognosis and drug resistance. EGFR is therefore a rational target for BC therapy development. This study demonstrated that a graviola fruit extract (GFE) significantly downregulated EGFR gene expression and inhibited the growth of BC cells and xenografts. GFE selectively inhibited the growth of EGFR-overexpressing human BC (MDA-MB-468) cells (IC(50) = 4.8 μg/ml) but had no effect on nontumorigenic human breast epithelial cells (MCF-10A). GFE significantly downregulated EGFR mRNA expression, arrested cell cycle in the G0/G1 phase, and induced apoptosis in MDA-MB-468 cells. In the mouse xenograft model, a 5-wk dietary treatment of GFE (200 mg/kg diet) significantly reduced the protein expression of EGFR, p-EGFR, and p-ERK in MDA-MB-468 tumors by 56%, 54%, and 32.5%, respectively. Overall, dietary GFE inhibited tumor growth, as measured by wet weight, by 32% (P < 0.01). These data showed that dietary GFE induced significant growth inhibition of MDA-MB-468 cells in vitro and in vivo through a mechanism involving the EGFR/ERK signaling pathway, suggesting that GFE may have a protective effect for women against EGFR-overexpressing BC.

Preneoplastic lesion growth driven by the death of adjacent normal stem cells

PubMed Central

Chao, Dennis L.; Eck, J. Thomas; Brash, Douglas E.; Maley, Carlo C.; Luebeck, E. Georg

2008-01-01

Clonal expansion of premalignant lesions is an important step in the progression to cancer. This process is commonly considered to be a consequence of sustaining a proliferative mutation. Here, we investigate whether the growth trajectory of clones can be better described by a model in which clone growth does not depend on a proliferative advantage. We developed a simple computer model of clonal expansion in an epithelium in which mutant clones can only colonize space left unoccupied by the death of adjacent normal stem cells. In this model, competition for space occurs along the frontier between mutant and normal territories, and both the shapes and the growth rates of lesions are governed by the differences between mutant and normal cells' replication or apoptosis rates. The behavior of this model of clonal expansion along a mutant clone's frontier, when apoptosis of both normal and mutant cells is included, matches the growth of UVB-induced p53-mutant clones in mouse dorsal epidermis better than a standard exponential growth model that does not include tissue architecture. The model predicts precancer cell mutation and death rates that agree with biological observations. These results support the hypothesis that clonal expansion of premalignant lesions can be driven by agents, such as ionizing or nonionizing radiation, that cause cell killing but do not directly stimulate cell replication. PMID:18815380

Niclosamide inhibits epithelial-mesenchymal transition and tumor growth in lapatinib-resistant human epidermal growth factor receptor 2-positive breast cancer.

PubMed

Liu, Junjun; Chen, Xiaosong; Ward, Toby; Mao, Yan; Bockhorn, Jessica; Liu, Xiaofei; Wang, Gen; Pegram, Mark; Shen, Kunwei

2016-02-01

Acquired resistance to lapatinib, a human epidermal growth factor receptor 2 kinase inhibitor, remains a clinical problem for women with human epidermal growth factor receptor 2-positive advanced breast cancer, as metastasis is commonly observed in these patients. Niclosamide, an anti-helminthic agent, has recently been shown to exhibit cytotoxicity to tumor cells with stem-like characteristics. This study was designed to identify the mechanisms underlying lapatinib resistance and to determine whether niclosamide inhibits lapatinib resistance by reversing epithelial-mesenchymal transition. Here, two human epidermal growth factor receptor 2-positive breast cancer cell lines, SKBR3 and BT474, were exposed to increasing concentrations of lapatinib to establish lapatinib-resistant cultures. Lapatinib-resistant SKBR3 and BT474 cells exhibited up-regulation of the phenotypic epithelial-mesenchymal transition markers Snail, vimentin and α-smooth muscle actin, accompanied by activation of nuclear factor-кB and Src and a concomitant increase in stem cell marker expression (CD44(high)/CD24(low)), compared to naive lapatinib-sensitive SKBR3 and BT474 cells, respectively. Interestingly, niclosamide reversed epithelial-mesenchymal transition, induced apoptosis and inhibited cell growth by perturbing aberrant signaling pathway activation in lapatinib-resistant human epidermal growth factor receptor 2-positive cells. The ability of niclosamide to alleviate stem-like phenotype development and invasion was confirmed. Collectively, our results demonstrate that lapatinib resistance correlates with epithelial-mesenchymal transition and that niclosamide inhibits lapatinib-resistant cell viability and epithelial-mesenchymal transition. These findings suggest a role of niclosamide or derivatives optimized for more favorable bioavailability not only in reversing lapatinib resistance but also in reducing metastatic potential during the treatment of human epidermal growth factor receptor 2-positive breast cancer. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Satellite Cell in Male and Female, Developing and Adult Mouse Muscle: Distinct Stem Cells for Growth and Regeneration

PubMed Central

Neal, Alice; Boldrin, Luisa; Morgan, Jennifer Elizabeth

2012-01-01

Satellite cells are myogenic cells found between the basal lamina and the sarcolemma of the muscle fibre. Satellite cells are the source of new myofibres; as such, satellite cell transplantation holds promise as a treatment for muscular dystrophies. We have investigated age and sex differences between mouse satellite cells in vitro and assessed the importance of these factors as mediators of donor cell engraftment in an in vivo model of satellite cell transplantation. We found that satellite cell numbers are increased in growing compared to adult and in male compared to female adult mice. We saw no difference in the expression of the myogenic regulatory factors between male and female mice, but distinct profiles were observed according to developmental stage. We show that, in contrast to adult mice, the majority of satellite cells from two week old mice are proliferating to facilitate myofibre growth; however a small proportion of these cells are quiescent and not contributing to this growth programme. Despite observed changes in satellite cell populations, there is no difference in engraftment efficiency either between satellite cells derived from adult or pre-weaned donor mice, male or female donor cells, or between male and female host muscle environments. We suggest there exist two distinct satellite cell populations: one for muscle growth and maintenance and one for muscle regeneration. PMID:22662253

Cellular expansion and gene expression in the developing grape (Vitis vinifera L.).

PubMed

Schlosser, J; Olsson, N; Weis, M; Reid, K; Peng, F; Lund, S; Bowen, P

2008-01-01

Expression profiles of genes involved in cell wall metabolism and water transport were compared with changes in grape (Vitis vinifera L.) berry growth, basic chemical composition, and the shape, size, and wall thickness of cells within tissues of the berry pericarp. Expression of cell wall-modifying and aquaporin genes in berry pericarp tissues generally followed a bimodal expression profile with high levels of expression coinciding with the two periods of rapid berry growth, stages I and III, and low levels of expression corresponding to the slow-growth period, stage II. Cellular expansion was observed throughout all tissues during stage I, and only mesocarp cellular expansion was observed during stage III. Expansion of only exocarp cells was evident during transition between stages II and III. Cell wall-modifying and aquaporin gene expression profiles followed similar trends in exocarp and mesocarp tissues throughout berry development, with the exception of the up-regulation of pectin methylesterase, pectate lyase, two aquaporin genes (AQ1 and AQ2), and two expansin genes (EXP3 and EXPL) during stage II, which was delayed in the exocarp tissue compared with mesocarp tissue. Exocarp endo-(1-->3)-beta-glucanase and expansin-like gene expression was concurrent with increases in epidermal and hypodermal cell wall thickness. These results indicate a potential role of the grape berry skin in modulating grape berry growth.

Light and gravity signals synergize in modulating plant development

PubMed Central

Vandenbrink, Joshua P.; Kiss, John Z.; Herranz, Raul; Medina, F. Javier

2014-01-01

Tropisms are growth-mediated plant movements that help plants to respond to changes in environmental stimuli. The availability of water and light, as well as the presence of a constant gravity vector, are all environmental stimuli that plants sense and respond to via directed growth movements (tropisms). The plant response to gravity (gravitropism) and the response to unidirectional light (phototropism) have long been shown to be interconnected growth phenomena. Here, we discuss the similarities in these two processes, as well as the known molecular mechanisms behind the tropistic responses. We also highlight research done in a microgravity environment in order to decouple two tropisms through experiments carried out in the absence of a significant unilateral gravity vector. In addition, alteration of gravity, especially the microgravity environment, and light irradiation produce important effects on meristematic cells, the undifferentiated, highly proliferating, totipotent cells which sustain plant development. Microgravity produces the disruption of meristematic competence, i.e., the decoupling of cell proliferation and cell growth, affecting the regulation of the cell cycle and ribosome biogenesis. Light irradiation, especially red light, mediated by phytochromes, has an activating effect on these processes. Phytohormones, particularly auxin, also are key mediators in these alterations. Upcoming experiments on the International Space Station will clarify some of the mechanisms and molecular players of the plant responses to these environmental signals involved in tropisms and the cell cycle. PMID:25389428

HMGB1 targeting by ethyl pyruvate suppresses malignant phenotype of human mesothelioma.

PubMed

Pellegrini, Laura; Xue, Jiaming; Larson, David; Pastorino, Sandra; Jube, Sandro; Forest, Kelly H; Saad-Jube, Zeyana Salim; Napolitano, Andrea; Pagano, Ian; Negi, Vishal S; Bianchi, Marco E; Morris, Paul; Pass, Harvey I; Gaudino, Giovanni; Carbone, Michele; Yang, Haining

2017-04-04

Human malignant mesothelioma (MM) is an aggressive cancer linked to asbestos and erionite exposure. We previously reported that High-Mobility Group Box-1 protein (HMGB1), a prototypic damage-associated molecular pattern, drives MM development and sustains MM progression. Moreover, we demonstrated that targeting HMGB1 inhibited MM cell growth and motility in vitro, reduced tumor growth in vivo, and prolonged survival of MM-bearing mice. Ethyl pyruvate (EP), the ethyl ester of pyruvic acid, has been shown to be an effective HMGB1 inhibitor in inflammation-related diseases and several cancers. Here, we studied the effect of EP on the malignant phenotype of MM cells in tissue culture and on tumor growth in vivo using an orthotopic MM xenograft model. We found that EP impairs HMGB1 secretion by MM cells leading to reduced RAGE expression and NF-κB activation. As a consequence, EP impaired cell motility, cell proliferation, and anchorage-independent growth of MM cells. Moreover, EP reduced HMGB1 serum levels in mice and inhibited the growth of MM xenografts.Our results indicate that EP effectively hampers the malignant phenotype of MM, offering a novel potential therapeutic approach to patients afflicted with this dismal disease.

Silicon web process development. [for low cost solar cells

NASA Technical Reports Server (NTRS)

Duncan, C. S.; Hopkins, R. H.; Seidensticker, R. G.; Mchugh, J. P.; Hill, F. E.; Heimlich, M. E.; Driggers, J. M.

1979-01-01

Silicon dendritic web, a single crystal ribbon shaped during growth by crystallographic forces and surface tension (rather than dies), is a highly promising base material for efficient low cost solar cells. The form of the product smooth, flexible strips 100 to 200 microns thick, conserves expensive silicon and facilitates automation of crystal growth and the subsequent manufacturing of solar cells. These characteristics, coupled with the highest demonstrated ribbon solar cell efficiency-15.5%-make silicon web a leading candidate to achieve, or better, the 1986 Low Cost Solar Array (LSA) Project cost objective of 50 cents per peak watt of photovoltaic output power. The main objective of the Web Program, technology development to significantly increase web output rate, and to show the feasibility for simultaneous melt replenishment and growth, have largely been accomplished. Recently, web output rates of 23.6 sq cm/min, nearly three times the 8 sq cm/min maximum rate of a year ago, were achieved. Webs 4 cm wide or greater were grown on a number of occassions.

Glucocorticoids promote development of the osteoblast phenotype by selectively modulating expression of cell growth and differentiation associated genes

NASA Technical Reports Server (NTRS)

Shalhoub, V.; Conlon, D.; Tassinari, M.; Quinn, C.; Partridge, N.; Stein, G. S.; Lian, J. B.

1992-01-01

To understand the mechanisms by which glucocorticoids promote differentiation of fetal rat calvaria derived osteoblasts to produce bone-like mineralized nodules in vitro, a panel of osteoblast growth and differentiation related genes that characterize development of the osteoblast phenotype has been quantitated in glucocorticoid-treated cultures. We compared the mRNA levels of osteoblast expressed genes in control cultures of subcultivated cells where nodule formation is diminished, to cells continuously (35 days) exposed to 10(-7) M dexamethasone, a synthetic glucocorticoid, which promotes nodule formation to levels usually the extent observed in primary cultures. Tritiated thymidine labelling revealed a selective inhibition of internodule cell proliferation and promotion of proliferation and differentiation of cells forming bone nodules. Fibronectin, osteopontin, and c-fos expression were increased in the nodule forming period. Alkaline phosphatase and type I collagen expression were initially inhibited in proliferating cells, then increased after nodule formation to support further growth and mineralization of the nodule. Expression of osteocalcin was 1,000-fold elevated in glucocorticoid-differentiated cultures in relation to nodule formation. Collagenase gene expression was also greater than controls (fivefold) with the highest levels observed in mature cultures (day 35). At this time, a rise in collagen and TGF beta was also observed suggesting turnover of the matrix. Short term (48 h) effects of glucocorticoid on histone H4 (reflecting cell proliferation), alkaline phosphatase, osteopontin, and osteocalcin mRNA levels reveal both up or down regulation as a function of the developmental stage of the osteoblast phenotype. A comparison of transcriptional levels of these genes by nuclear run-on assays to mRNA levels indicates that glucocorticoids exert both transcriptional and post-transcriptional effects. Further, the presence of glucocorticoids enhances the vitamin D3 effect on gene expression. Those genes which are upregulated by 1,25(OH)2D3 are transcribed at an increased rate by dexamethasone, while those genes which are inhibited by vitamin D3 remain inhibited in the presence of dexamethasone and D3. We propose that the glucocorticoids promote changes in gene expression involved in cell-cell and cell-extracellular matrix signaling mechanisms that support the growth and differentiation of cells capable of osteoblast phenotype development and bone tissue-like organization, while inhibiting the growth of cells that cannot progress to the mature osteoblast phenotype in fetal rat calvarial cultures.

Exposure cell number during feeder cell growth-arrest by Mitomycin C is a critical pharmacological aspect in stem cell culture system.

PubMed

Chugh, Rishi Man; Chaturvedi, Madhusudan; Yerneni, Lakshmana Kumar

2016-01-01

Growth-arrested feeder cells following Mitomycin C treatment are instrumental in stem cell culture allowing development of regenerative strategies and alternatives to animal testing in drug discovery. The concentration of Mitomycin C and feeder cell type was described to affect feeder performance but the criticality of feeder cell exposure density was not addressed. We hypothesize that the exposure cell density influences the effectiveness of Mitomycin C in an arithmetic manner. Three different exposure cell densities of Swiss 3T3 fibroblasts were treated with a range of Mitomycin C concentrations for 2h. The cells were replaced and the viable cells counted on 3, 6, 9, 12 and 20days. The cell extinctions were compared with doses per cell which were derived by dividing the product of concentration and volume of Mitomycin C solution with exposure cell number. The periodic post-treatment feeder cell extinctions were not just dependent on Mitomycin C concentration but also on dose per cell. Analysis of linearity between viable cell number and Mitomycin C dose per cell derived from the concentrations of 3 to 10μg/ml revealed four distinct categories of growth-arrest. Confluent cultures exposed to low concentration showed growth-arrest failure. The in vitro cell density titration can facilitate prediction of a compound's operational in vivo dosing. For containing the growth arrest failure, an arithmetic volume derivation strategy is proposed by fixing the exposure density to a safe limit. The feeder extinction characteristics are critical for streamlining the stem cell based pharmacological and toxicological assays. Copyright © 2016 Elsevier Inc. All rights reserved.

Mutation of a chitinase-like gene causes ectopic deposition of lignin, aberrant cell shapes, and overproduction of ethylene.

PubMed

Zhong, Ruiqin; Kays, Stanley J; Schroeder, Betty P; Ye, Zheng-Hua

2002-01-01

Chitinase-like proteins have long been proposed to play roles in normal plant growth and development, but no mutations in chitinase-like genes have been obtained previously to support this hypothesis. In this study, we have shown that the gene responsible for the elp1 mutation in Arabidopsis encodes a chitinase-like protein (AtCTL1). Mutation of this chitinase-like gene caused ectopic deposition of lignin and aberrant shapes of cells with incomplete cell walls in the pith of inflorescence stems. The AtCTL1 gene was expressed in all organs during normal plant growth and development, but it was not induced by wounding, salicylic acid, pectin fragments, or ethylene. Consistent with its ubiquitous expression pattern, mutation of the AtCTL1 gene affected many aspects of plant growth and development, including exaggerated hook curvature, reduced length and increased diameter of hypocotyls in dark-grown seedlings, and reduced root length and increased number of root hairs in light-grown seedlings. The mutant phenotypes could be rescued partially by ethylene inhibitors, and ethylene production in the mutant was significantly greater than in the wild type. Together, these results suggest that AtCTL1, a chitinase-like gene, is essential for normal plant growth and development in Arabidopsis.

Modulation of Medium pH by Caulobacter crescentus Facilitates Recovery from Uranium-Induced Growth Arrest

PubMed Central

Park, Dan M.

2014-01-01

The oxidized form of uranium [U(VI)] predominates in oxic environments and poses a major threat to ecosystems. Due to its ability to mineralize U(VI), the oligotroph Caulobacter crescentus is an attractive candidate for U(VI) bioremediation. However, the physiological basis for U(VI) tolerance is unclear. Here we demonstrated that U(VI) caused a temporary growth arrest in C. crescentus and three other bacterial species, although the duration of growth arrest was significantly shorter for C. crescentus. During the majority of the growth arrest period, cell morphology was unaltered and DNA replication initiation was inhibited. However, during the transition from growth arrest to exponential phase, cells with shorter stalks were observed, suggesting a decoupling between stalk development and the cell cycle. Upon recovery from growth arrest, C. crescentus proliferated with a growth rate comparable to that of a control without U(VI), although a fraction of these cells appeared filamentous with multiple replication start sites. Normal cell morphology was restored by the end of exponential phase. Cells did not accumulate U(VI) resistance mutations during the prolonged growth arrest, but rather, a reduction in U(VI) toxicity occurred concomitantly with an increase in medium pH. Together, these data suggest that C. crescentus recovers from U(VI)-induced growth arrest by reducing U(VI) toxicity through pH modulation. Our finding represents a unique U(VI) detoxification strategy and provides insight into how microbes cope with U(VI) under nongrowing conditions, a metabolic state that is prevalent in natural environments. PMID:25002429

Impaired tissue growth is mediated by checkpoint kinase 1 (CHK1) in the integrated stress response

PubMed Central

Malzer, Elke; Daly, Marie-Louise; Moloney, Aileen; Sendall, Timothy J.; Thomas, Sally E.; Ryder, Edward; Ryoo, Hyung Don; Crowther, Damian C.; Lomas, David A.; Marciniak, Stefan J.

2010-01-01

The integrated stress response (ISR) protects cells from numerous forms of stress and is involved in the growth of solid tumours; however, it is unclear how the ISR acts on cellular proliferation. We have developed a model of ISR signalling with which to study its effects on tissue growth. Overexpression of the ISR kinase PERK resulted in a striking atrophic eye phenotype in Drosophila melanogaster that could be rescued by co-expressing the eIF2α phosphatase GADD34. A genetic screen of 3000 transposon insertions identified grapes, the gene that encodes the Drosophila orthologue of checkpoint kinase 1 (CHK1). Knockdown of grapes by RNAi rescued eye development despite ongoing PERK activation. In mammalian cells, CHK1 was activated by agents that induce ER stress, which resulted in a G2 cell cycle delay. PERK was both necessary and sufficient for CHK1 activation. These findings indicate that non-genotoxic misfolded protein stress accesses DNA-damage-induced cell cycle checkpoints to couple the ISR to cell cycle arrest. PMID:20682638

Mechanisms of Hippo pathway regulation

PubMed Central

Meng, Zhipeng; Moroishi, Toshiro; Guan, Kun-Liang

2016-01-01

The Hippo pathway was initially identified in Drosophila melanogaster screens for tissue growth two decades ago and has been a subject extensively studied in both Drosophila and mammals in the last several years. The core of the Hippo pathway consists of a kinase cascade, transcription coactivators, and DNA-binding partners. Recent studies have expanded the Hippo pathway as a complex signaling network with >30 components. This pathway is regulated by intrinsic cell machineries, such as cell–cell contact, cell polarity, and actin cytoskeleton, as well as a wide range of signals, including cellular energy status, mechanical cues, and hormonal signals that act through G-protein-coupled receptors. The major functions of the Hippo pathway have been defined to restrict tissue growth in adults and modulate cell proliferation, differentiation, and migration in developing organs. Furthermore, dysregulation of the Hippo pathway leads to aberrant cell growth and neoplasia. In this review, we focus on recent developments in our understanding of the molecular actions of the core Hippo kinase cascade and discuss key open questions in the regulation and function of the Hippo pathway. PMID:26728553

Arabidopsis leucine-rich repeat extensin (LRX) proteins modify cell wall composition and influence plant growth.

PubMed

Draeger, Christian; Ndinyanka Fabrice, Tohnyui; Gineau, Emilie; Mouille, Grégory; Kuhn, Benjamin M; Moller, Isabel; Abdou, Marie-Therese; Frey, Beat; Pauly, Markus; Bacic, Antony; Ringli, Christoph

2015-06-24

Leucine-rich repeat extensins (LRXs) are extracellular proteins consisting of an N-terminal leucine-rich repeat (LRR) domain and a C-terminal extensin domain containing the typical features of this class of structural hydroxyproline-rich glycoproteins (HRGPs). The LRR domain is likely to bind an interaction partner, whereas the extensin domain has an anchoring function to insolubilize the protein in the cell wall. Based on the analysis of the root hair-expressed LRX1 and LRX2 of Arabidopsis thaliana, LRX proteins are important for cell wall development. The importance of LRX proteins in non-root hair cells and on the structural changes induced by mutations in LRX genes remains elusive. The LRX gene family of Arabidopsis consists of eleven members, of which LRX3, LRX4, and LRX5 are expressed in aerial organs, such as leaves and stem. The importance of these LRX genes for plant development and particularly cell wall formation was investigated. Synergistic effects of mutations with gradually more severe growth retardation phenotypes in double and triple mutants suggest a similar function of the three genes. Analysis of cell wall composition revealed a number of changes to cell wall polysaccharides in the mutants. LRX3, LRX4, and LRX5, and most likely LRX proteins in general, are important for cell wall development. Due to the complexity of changes in cell wall structures in the lrx mutants, the exact function of LRX proteins remains to be determined. The increasingly strong growth-defect phenotypes in double and triple mutants suggests that the LRX proteins have similar functions and that they are important for proper plant development.

Dynamic Scaling of Lipofuscin Deposition in Aging Cells

NASA Astrophysics Data System (ADS)

Family, Fereydoon; Mazzitello, K. I.; Arizmendi, C. M.; Grossniklaus, H. E.

2011-07-01

Lipofuscin is a membrane-bound cellular waste that can be neither degraded nor ejected from the cell but can only be diluted through cell division and subsequent growth. The fate of postmitotic (non-dividing) cells such as neurons, cardiac myocytes, skeletal muscle fibers, and retinal pigment epithelial cells (RPE) is to accumulate lipofuscin, which as an "aging pigment" has been considered a reliable biomarker for the age of cells. Environmental stress can accelerate the accumulation of lipofuscin. For example, accumulation in brain cells appears to be an important issue connected with heavy consumption of alcohol. Lipofuscin is made of free-radical-damaged protein and fat, whose abnormal accumulation is related to a range of disorders including Type IV mucolipidosis (ML4), Amyotrophic Lateral Sclerosis (ALS), Alzheimer's disease, Parkinson disease, and age-related macular degeneration (AMD) which is the leading cause of blindness beyond the age of 50 years. The study of lipofuscin formation and growth is important, because of their association with cellular aging. We introduce a model of non-equilibrium cluster growth and aggregation that we have developed for studying the formation and growth of lipofuscin. As an example of lipofuscin deposit in a given kind of postmitotic cell, we study the kinetics of lipofuscin growth in a RPE cell. Our results agree with a linear growth of the number of lipofuscin granules with age. We apply the dynamic scaling approach to our model and find excellent data collapse for the cluster size distribution. An unusual feature of our model is that while small particles are removed from the cell the larger ones become fixed and grow by aggregation.

Morphogenetic circuitry regulating growth and development in the dimorphic pathogen Penicillium marneffei.

PubMed

Boyce, Kylie J; Andrianopoulos, Alex

2013-02-01

Penicillium marneffei is an emerging human-pathogenic fungus endemic to Southeast Asia. Like a number of other fungal pathogens, P. marneffei exhibits temperature-dependent dimorphic growth and grows in two distinct cellular morphologies, hyphae at 25°C and yeast cells at 37°C. Hyphae can differentiate to produce the infectious agents, asexual spores (conidia), which are inhaled into the host lung, where they are phagocytosed by pulmonary alveolar macrophages. Within macrophages, conidia germinate into unicellular yeast cells, which divide by fission. This minireview focuses on the current understanding of the genes required for the morphogenetic control of conidial germination, hyphal growth, asexual development, and yeast morphogenesis in P. marneffei.

Evidence for a Transketolase-Mediated Metabolic Checkpoint Governing Biotrophic Growth in Rice Cells by the Blast Fungus Magnaporthe oryzae

PubMed Central

Fernandez, Jessie; Marroquin-Guzman, Margarita; Wilson, Richard A.

2014-01-01

The blast fungus Magnaporthe oryzae threatens global food security through the widespread destruction of cultivated rice. Foliar infection requires a specialized cell called an appressorium that generates turgor to force a thin penetration hypha through the rice cuticle and into the underlying epidermal cells, where the fungus grows for the first days of infection as a symptomless biotroph. Understanding what controls biotrophic growth could open new avenues for developing sustainable blast intervention programs. Here, using molecular genetics and live-cell imaging, we dismantled M. oryzae glucose-metabolizing pathways to reveal that the transketolase enzyme, encoded by TKL1, plays an essential role in facilitating host colonization during rice blast disease. In the absence of transketolase, Δtkl1 mutant strains formed functional appressoria that penetrated rice cuticles successfully and developed invasive hyphae (IH) in rice cells from primary hyphae. However, Δtkl1 could not undertake sustained biotrophic growth or cell-to-cell movement. Transcript data and observations using fluorescently labeled histone H1:RFP fusion proteins indicated Δtkl1 mutant strains were alive in host cells but were delayed in mitosis. Mitotic delay could be reversed and IH growth restored by the addition of exogenous ATP, a metabolite depleted in Δtkl1 mutant strains. We show that ATP might act via the TOR signaling pathway, and TOR is likely a downstream target of activation for TKL1. TKL1 is also involved in controlling the migration of appressorial nuclei into primary hyphae in host cells. When taken together, our results indicate transketolase has a novel role in mediating - via ATP and TOR signaling - an in planta-specific metabolic checkpoint that controls nuclear migration from appressoria into primary hyphae, prevents mitotic delay in early IH and promotes biotrophic growth. This work thus provides new information about the metabolic strategies employed by M. oryzae to enable rice cell colonization. PMID:25188286

Extracellular matrix as a solid-state regulator in angiogenesis: identification of new targets for anti-cancer therapy

NASA Technical Reports Server (NTRS)

Ingber, D. E.

1992-01-01

Angiogenesis, the growth of blood capillaries, is regulated by soluble growth factors and insoluble extracellular matrix (ECM) molecules. Soluble angiogenic mitogens act over large distances to initiate capillary growth whereas changes in ECM govern whether individual cells will grow, differentiate, or involute in response to these stimuli in the local tissue microenvironment. Analysis of this local control mechanism has revealed that ECM molecules switch capillary endothelial cells between differentiation and growth by both binding specific transmembrane integrin receptors and physically resisting cell-generated mechanical loads that are applied to these receptors. Control of capillary endothelial cell form and function therefore may be exerted by altering the mechanical properties of the ECM as well as its chemical composition. Understanding of this mechanochemical control mechanism has led to the development of new angiogenesis inhibitors that may be useful for the treatment of cancer.

Physiological and morphological changes during early and later stages of fruit growth in Capsicum annuum.

PubMed

Tiwari, Aparna; Vivian-Smith, Adam; Ljung, Karin; Offringa, Remko; Heuvelink, Ep

2013-03-01

Fruit-set involves a series of physiological and morphological changes that are well described for tomato and Arabidopsis, but largely unknown for sweet pepper (Capsicum annuum). The aim of this paper is to investigate whether mechanisms of fruit-set observed in Arabidopsis and tomato are also applicable to C. annuum. To do this, we accurately timed the physiological and morphological changes in a post-pollinated and un-pollinated ovary. A vascular connection between ovule and replum was observed in fertilized ovaries that undergo fruit development, and this connection was absent in unfertilized ovaries that abort. This indicates that vascular connection between ovule and replum is an early indicator for successful fruit development after pollination and fertilization. Evaluation of histological changes in the carpel of a fertilized and unfertilized ovary indicated that increase in cell number and cell diameter both contribute to early fruit growth. Cell division contributes more during early fruit growth while cell expansion contributes more at later stages of fruit growth in C. annuum. The simultaneous occurrence of a peak in auxin concentration and a strong increase in cell diameter in the carpel of seeded fruits suggest that indole-3-acetic acid stimulates a major increase in cell diameter at later stages of fruit growth. The series of physiological and morphological events observed during fruit-set in C. annuum are similar to what has been reported for tomato and Arabidopsis. This indicates that tomato and Arabidopsis are suitable model plants to understand details of fruit-set mechanisms in C. annuum. Copyright © Physiologia Plantarum 2012.

APSR1, a novel gene required for meristem maintenance, is negatively regulated by low phosphate availability.

PubMed

González-Mendoza, Víctor; Zurita-Silva, Andrés; Sánchez-Calderón, Lenin; Sánchez-Sandoval, María Eugenia; Oropeza-Aburto, Araceli; Gutiérrez-Alanís, Dolores; Alatorre-Cobos, Fulgencio; Herrera-Estrella, Luis

2013-05-01

Proper root growth is crucial for anchorage, exploration, and exploitation of the soil substrate. Root growth is highly sensitive to a variety of environmental cues, among them water and nutrient availability have a great impact on root development. Phosphorus (P) availability is one of the most limiting nutrients that affect plant growth and development under natural and agricultural environments. Root growth in the direction of the long axis proceeds from the root tip and requires the coordinated activities of cell proliferation, cell elongation and cell differentiation. Here we report a novel gene, APSR1 (Altered Phosphate Starvation Response1), involved in root meristem maintenance. The loss of function mutant apsr1-1 showed a reduction in primary root length and root apical meristem size, short differentiated epidermal cells and long root hairs. Expression of APSR1 gene decreases in response to phosphate starvation and apsr1-1 did not show the typical progressive decrease of undifferentiated cells at root tip when grown under P limiting conditions. Interestingly, APSR1 expression pattern overlaps with root zones of auxin accumulation. Furthermore, apsr1-1 showed a clear decrease in the level of the auxin transporter PIN7. These data suggest that APSR1 is required for the coordination of cell processes necessary for correct root growth in response to phosphate starvation conceivably by direct or indirect modulation of PIN7. We also propose, based on its nuclear localization and structure, that APSR1 may potentially be a member of a novel group of transcription factors. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

The Populus Class III HD ZIP transcription factor POPCORONA affects cell differentiation during secondary growth of woody stems

Treesearch

Juan Du; Eriko Miura; Marcel Robischon; Ciera Martinez; Andrew Groover

2011-01-01

The developmental mechanisms regulating cell differentiation and patterning during the secondary growth of woody tissues are poorly understood. Class III HD ZIP transcription factors are evolutionarily ancient and play fundamental roles in various aspects of plant development. Here we investigate the role of a Class III HD ZIP transcription factor, ...

Real-time monitoring of the budding index in Saccharomyces cerevisiae batch cultivations with in situ microscopy.

PubMed

Marbà-Ardébol, Anna-Maria; Emmerich, Jörn; Muthig, Michael; Neubauer, Peter; Junne, Stefan

2018-05-15

The morphology of yeast cells changes during budding, depending on the growth rate and cultivation conditions. A photo-optical microscope was adapted and used to observe such morphological changes of individual cells directly in the cell suspension. In order to obtain statistically representative samples of the population without the influence of sampling, in situ microscopy (ISM) was applied in the different phases of a Saccharomyces cerevisiae batch cultivation. The real-time measurement was performed by coupling a photo-optical probe to an automated image analysis based on a neural network approach. Automatic cell recognition and classification of budding and non-budding cells was conducted successfully. Deviations between automated and manual counting were considerably low. A differentiation of growth activity across all process stages of a batch cultivation in complex media became feasible. An increased homogeneity among the population during the growth phase was well observable. At growth retardation, the portion of smaller cells increased due to a reduced bud formation. The maturation state of the cells was monitored by determining the budding index as a ratio between the number of cells, which were detected with buds and the total number of cells. A linear correlation between the budding index as monitored with ISM and the growth rate was found. It is shown that ISM is a meaningful analytical tool, as the budding index can provide valuable information about the growth activity of a yeast cell, e.g. in seed breeding or during any other cultivation process. The determination of the single-cell size and shape distributions provided information on the morphological heterogeneity among the populations. The ability to track changes in cell morphology directly on line enables new perspectives for monitoring and control, both in process development and on a production scale.

Transcriptomic analysis reveals vacuolar Na+ (K+)/H+ antiporter gene contributing to growth, development, and defense in switchgrass (Panicum virgatum L.).

PubMed

Huang, Yanhua; Cui, Xin; Cen, Huifang; Wang, Kehua; Zhang, Yunwei

2018-04-10

Intracellular Na + (K + )/H + antiporters (NHXs) have pivotal functions in regulating plant growth, development, and resistance to a range of stresses. To gain insight into the molecular events underlying their actions in switchgrass (Panicum virgatum L.), we analyzed transcriptomic changes between PvNHX1-overexpression transgenic lines and wild-type (WT) plants using RNA sequencing (RNA-seq) technology. The comparison of transcriptomic data from the WT and transgenic plants revealed a large number of differentially expressed genes (DEGs) in the latter. Gene ontology (GO) and KEGG pathway analyses showed that these DEGs were associated with a wide range of functions, and participated in many biological processes. For example, we found that PvNHX1 had an important role in plant growth through its regulation of photosynthetic activity and cell expansion. In addition, PvNHX1 regulated K + homeostasis, cell expansion and pollen development, indicating that it has unique and specific roles in flower development. We also found that transgenic switchgrass exhibited a higher level of transcription of defense-related genes, especially those involved in disease resistance. We showed that PvNHX1 had an important role in plant growth and development through its regulation of photosynthetic activity, cell expansion, K + homeostasis, and pollen development. Additionally, PvNHX1 overexpression activated a complex signal transduction network in response to various biotic and abiotic stresses. In relation to plant growth, development, and defense responses, PvNHX1 also had a vital regulatory role in the formation of a series of plant hormones and transcription factors (TFs). The reliability of the RNA-seq data was confirmed by quantitative real-time PCR. Our data provide a valuable foundation for further research into the molecular mechanisms and physiological roles of NHXs in plants.

FGF2-mediated reciprocal tumor cell-endothelial cell interplay contributes to the growth of chemoresistant cells: a potential mechanism for superficial bladder cancer recurrence.

PubMed

Chen, Yule; Zhu, Guodong; Wu, Kaijie; Gao, Yang; Zeng, Jin; Shi, Qi; Guo, Peng; Wang, Xinyang; Chang, Luke S; Li, Lei; He, Dalin

2016-04-01

Patients with superficial bladder cancer can be definitively cured by one single transurethral resection (TUR) with additional intravesical chemotherapy; however, up to 75 % of cases display frequent and multiple recurrences. One of the major causes of recurrence is that chemotherapeutic drugs used in intravesical regimens may induce chemoresistance. However, the mechanisms by which these chemoresistant cells develop into recurrent tumors remain unclear. Recent clinical evidence revealed that the expression of pro-angiogenic factor FGF2 was associated with early local relapse in patients with superficial bladder cancer. In this study, we conducted a preliminary investigation of the mechanisms of chemoresistant cells mediated bladder cancer recurrence, focusing on FGF2-initiated tumor cell-endothelial cell interaction on chemoresistant cancer cell growth. We found that the expression of FGF2 was increased in chemoresistant bladder cell lines and in bladder tissues after intravesical chemotherapy. Although chemoresistant bladder cells grow slower than parental cells, chemoresistant bladder cancer cells had stronger ability than parental cells to stimulate endothelial cell migration, growth, and tube formation by producing FGF2. Inversely, endothelial cells significantly promoted chemoresistant bladder cancer growth in vitro and in vivo. Thus, targeting chemotherapy-induced FGF2 upregulation may provide a promising approach to manage the recurrence of superficial bladder cancer.

ASSESSMENT OF PC12 CELL DIFFERENTIATION AND NEURITE GROWTH: A COMPARISON OF MORPHOLOGICAL AND NEUROCHEMICAL MEASURES.

EPA Science Inventory

In order to screen large numbers of chemicals for their potential to produce developmental neurotoxicity new, in vitro methods are needed. One approach is to develop methods based on the biologic processes which underlie brain development including the growth and maturation of ce...

Phytoplasmal infection derails genetically preprogrammed meristem fate and alters plant architecture

USDA-ARS?s Scientific Manuscript database

In the life cycle of higher plants, it is the fate of meristem cells that determines the pattern of growth and development, and therefore plant morphotype and fertility. Floral transition, the turning point from vegetative growth to reproductive development, is achieved via genetically-programmed s...

Inhibition of platelet-derived growth factor signaling prevents muscle fiber growth during skeletal muscle hypertrophy.

PubMed

Sugg, Kristoffer B; Korn, Michael A; Sarver, Dylan C; Markworth, James F; Mendias, Christopher L

2017-03-01

The platelet-derived growth factor receptors alpha and beta (PDGFRα and PDGFRβ) mark fibroadipogenic progenitor cells/fibroblasts and pericytes in skeletal muscle, respectively. While the role that these cells play in muscle growth and development has been evaluated, it was not known whether the PDGF receptors activate signaling pathways that control transcriptional and functional changes during skeletal muscle hypertrophy. To evaluate this, we inhibited PDGFR signaling in mice subjected to a synergist ablation muscle growth procedure, and performed analyses 3 and 10 days after induction of hypertrophy. The results from this study indicate that PDGF signaling is required for fiber hypertrophy, extracellular matrix production, and angiogenesis that occur during muscle growth. © 2017 Federation of European Biochemical Societies.

Involvement of immune cells in the pathogenesis of endometriosis.

PubMed

Izumi, Gentaro; Koga, Kaori; Takamura, Masashi; Makabe, Tomoko; Satake, Erina; Takeuchi, Arisa; Taguchi, Ayumi; Urata, Yoko; Fujii, Tomoyuki; Osuga, Yutaka

2018-02-01

Endometriosis is characterized by the implantation and growth of endometriotic tissues outside the uterus. It is widely accepted the theory that endometriosis is caused by the implantation of endometrial tissue from retrograde menstruation; however, retrograde menstruation occurs in almost all women and other factors are required for the establishment of endometriosis, such as cell survival, cell invasion, angiogenesis, and cell growth. Immune factors in the local environment may, therefore, contribute to the formation and progression of endometriosis. Current evidence supports the involvement of immune cells in the pathogenesis of endometriosis. Peritoneal neutrophils and macrophages secrete biochemical factors that help endometriotic cell growth and invasion, and angiogenesis. Peritoneal macrophages and NK cells in endometriosis have limited capability of eliminating endometrial cells in the peritoneal cavity. An imbalance of T cell subsets leads to aberrant cytokine secretions and inflammation that results in the growth of endometriosis lesions. It is still uncertain whether these immune cells have a role in the initial cause and/or stimulate actions that enhance disease; however, in either case, modulating the actions of these cells may prevent initiation or disease progression. Further studies are needed to deepen the understanding of the pathology of endometriosis and to develop novel management approaches of benefit to women suffering from this disease. © 2018 Japan Society of Obstetrics and Gynecology.

Nuclear ribosome biogenesis mediated by the DIM1A rRNA dimethylase is required for organized root growth and epidermal patterning in Arabidopsis.

PubMed

Wieckowski, Yana; Schiefelbein, John

2012-07-01

Position-dependent patterning of hair and non-hair cells in the Arabidopsis thaliana root epidermis is a powerful system to study the molecular basis of cell fate specification. Here, we report an epidermal patterning mutant affecting the ADENOSINE DIMETHYL TRANSFERASE 1A (DIM1A) rRNA dimethylase gene, predicted to participate in rRNA posttranscriptional processing and base modification. Consistent with a role in ribosome biogenesis, DIM1A is preferentially expressed in regions of rapid growth, and its product is nuclear localized with nucleolus enrichment. Furthermore, DIM1A preferentially accumulates in the developing hair cells, and the dim1A point mutant alters the cell-specific expression of the transcriptional regulators GLABRA2, CAPRICE, and WEREWOLF. Together, these findings suggest that establishment of cell-specific gene expression during root epidermis development is dependent upon proper ribosome biogenesis, possibly due to the sensitivity of the cell fate decision to relatively small differences in gene regulatory activities. Consistent with its effect on the predicted S-adenosyl-l-Met binding site, dim1A plants lack the two 18S rRNA base modifications but exhibit normal pre-rRNA processing. In addition to root epidermal defects, the dim1A mutant exhibits abnormal root meristem division, leaf development, and trichome branching. Together, these findings provide new insights into the importance of rRNA base modifications and translation regulation for plant growth and development.

Nuclear Ribosome Biogenesis Mediated by the DIM1A rRNA Dimethylase Is Required for Organized Root Growth and Epidermal Patterning in Arabidopsis[C][W

PubMed Central

Wieckowski, Yana; Schiefelbein, John

2012-01-01

Position-dependent patterning of hair and non-hair cells in the Arabidopsis thaliana root epidermis is a powerful system to study the molecular basis of cell fate specification. Here, we report an epidermal patterning mutant affecting the ADENOSINE DIMETHYL TRANSFERASE 1A (DIM1A) rRNA dimethylase gene, predicted to participate in rRNA posttranscriptional processing and base modification. Consistent with a role in ribosome biogenesis, DIM1A is preferentially expressed in regions of rapid growth, and its product is nuclear localized with nucleolus enrichment. Furthermore, DIM1A preferentially accumulates in the developing hair cells, and the dim1A point mutant alters the cell-specific expression of the transcriptional regulators GLABRA2, CAPRICE, and WEREWOLF. Together, these findings suggest that establishment of cell-specific gene expression during root epidermis development is dependent upon proper ribosome biogenesis, possibly due to the sensitivity of the cell fate decision to relatively small differences in gene regulatory activities. Consistent with its effect on the predicted S-adenosyl-l-Met binding site, dim1A plants lack the two 18S rRNA base modifications but exhibit normal pre-rRNA processing. In addition to root epidermal defects, the dim1A mutant exhibits abnormal root meristem division, leaf development, and trichome branching. Together, these findings provide new insights into the importance of rRNA base modifications and translation regulation for plant growth and development. PMID:22829145

Characterization of growth and Oryctes rhinoceros nudivirus production in attached cultures of the DSIR-HA-1179 coleopteran insect cell line.

PubMed

Pushparajan, Charlotte; Claus, Juan Daniel; Marshall, Sean David Goldie; Visnovsky, Gabriel

2013-12-01

The DSIR-HA-1179 coleopteran cell line is a susceptible and permissive host to the Oryctes rhinoceros nudivirus (OrNV), which has been used as a biocontrol agent against the coconut rhinoceros beetle (Oryctes rhinoceros); a pest of palms in the Asia-Pacific region. However, little is known about growth and metabolism of this cell line, knowledge of which is necessary to develop an in vitro large-scale OrNV production process. The strong anchorage-dependent characteristics of the cell line, its particular fragility and its tendency to form dense clumps when manipulated, are the most likely reasons that have precluded further development of the cell line. In order to characterize DSIR-HA-1179 cells, there was first a need for a reliable technique to count the cells. A homogenous cell suspension suitable for enumeration could be produced by treatment with TrypLE Express™ with optimum mean time for cell release calculated as 30 min. The cell line was adapted to grow in four serum-supplemented culture media namely TC-100, IPL-41, Sf-900 II and Sf-900 III and cell growth, glucose consumption, lactate and ammonia production were assessed from static-batch cultures. The maximum viable cell density was reached in Sf-900 II (17.9 × 10(5) cells/ml), with the maximum specific growth rate observed in this culture medium as well (0.0074 h(-1)). Higher production of OrNV was observed in IPL-41 and TC-100 (4.1 × 10(7) TCID50/ml) than in cultures infected in Sf-900 III (2.0 × 10(7) TCID50/ml) and Sf-900 II (1.4 × 10(7) TCID50/ml). At the end of the growth period, glucose was completely consumed in cultures grown in TC-100, while remained in excess in the other three culture media. The cell line produced lactate and ammonia to very low levels in the TC-100 culture medium which is a promising aspect for its cultivation at large-scale.

Growth factor-induced morphological, physiological and molecular characteristics in cerebral endothelial cells.

PubMed

Krizbai, I A; Bauer, H; Amberger, A; Hennig, B; Szabó, H; Fuchs, R; Bauer, H C

2000-09-01

The capacity of vascular endothelial cells to modulate their phenotype in response to changes in environmental conditions is one of the most important characteristics of this cell type. Since different growth factors may play an important signalling role in this adaptive process we have investigated the effect of endothelial cell growth factor (ECGF) on morphological, physiological and molecular characteristics of cerebral endothelial cells (CECs). CECs grown in the presence of ECGF and its cofactor heparin exhibit an epithelial-like morphology (type I CECs). Upon removal of growth factors, CECs develop an elongated spindle-like shape (type II CECs) which is accompanied by the reorganization of actin filaments and the induction of alpha-actin expression. Since one of the most important functions of CECs is the creation of a selective diffusion barrier between the blood and the central nervous system (CNS), we have studied the expression of junction-related proteins in both cell types. We have found that removal of growth factors from endothelial cultures leads to the downregulation of cadherin and occludin protein levels. The loss of junctional proteins was accompanied by a significant increase in the migratory activity and an altered protease activity profile of the cells. TGF-beta1 suppressed endothelial migration in all experiments. Our data provide evidence to suggest that particular endothelial functions are largely controlled by the presence of growth factors. The differences in adhesiveness and migration may play a role in important physiological and pathological processes of endothelial cells such as vasculogenesis or tumor progression.

The skeletal vascular system - Breathing life into bone tissue.

PubMed

Stegen, Steve; Carmeliet, Geert

2017-08-26

During bone development, homeostasis and repair, a dense vascular system provides oxygen and nutrients to highly anabolic skeletal cells. Characteristic for the vascular system in bone is the serial organization of two capillary systems, each typified by specific morphological and physiological features. Especially the arterial capillaries mediate the growth of the bone vascular system, serve as a niche for skeletal and hematopoietic progenitors and couple angiogenesis to osteogenesis. Endothelial cells and osteoprogenitor cells interact not only physically, but also communicate to each other by secretion of growth factors. A vital angiogenic growth factor is vascular endothelial growth factor and its expression in skeletal cells is controlled by osteogenic transcription factors and hypoxia signaling, whereas the secretion of angiocrine factors by endothelial cells is regulated by Notch signaling, blood flow and possibly hypoxia. Bone loss and impaired fracture repair are often associated with reduced and disorganized blood vessel network and therapeutic targeting of the angiogenic response may contribute to enhanced bone regeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

Culture on 3D Chitosan-Hyaluronic Acid Scaffolds Enhances Stem Cell Marker Expression and Drug Resistance in Human Glioblastoma Cancer Stem Cells.

PubMed

Wang, Kui; Kievit, Forrest M; Erickson, Ariane E; Silber, John R; Ellenbogen, Richard G; Zhang, Miqin

2016-12-01

The lack of in vitro models that support the growth of glioblastoma (GBM) stem cells (GSCs) that underlie clinical aggressiveness hinders developing new, effective therapies for GBM. While orthotopic patient-derived xenograft models of GBM best reflect in vivo tumor behavior, establishing xenografts is a time consuming, costly, and frequently unsuccessful endeavor. To address these limitations, a 3D porous scaffold composed of chitosan and hyaluronic acid (CHA) is synthesized. Growth and expression of the cancer stem cell (CSC) phenotype of the GSC GBM6 taken directly from fresh xenogratfs grown on scaffolds or as adherent monolayers is compared. While 2D adherent cultures grow as monolayers of flat epitheliod cells, GBM6 cells proliferate within pores of CHA scaffolds as clusters of self-adherent ovoid cells. Growth on scaffolds is accompanied by greater expression of genes that mediate epithelial-mesenchymal transition and maintain a primitive, undifferentiated phenotype, hallmarks of CSCs. Scaffold-grown cells also display higher expression of genes that promote resistance to hypoxia-induced oxidative stress. In accord, scaffold-grown cells show markedly greater resistance to clinically utilized alkylating agents compared to adherent cells. These findings suggest that our CHA scaffolds better mimic in vivo biological and clinical behavior and provide insights for developing novel individualized treatments. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Proliferative activity and branching morphogenesis in the human prostate: a closer look at pre- and postnatal prostate growth.

PubMed

Xue, Y; Sonke, G; Schoots, C; Schalken, J; Verhofstad, A; de la Rosette, J; Smedts, F

2001-10-01

To gain further insight into the molecular cell biologic features of prostate development, we investigated the proliferative activity of prostate epithelial and stromal cells and their topographic relationship with neuroendocrine (NE) cell distribution and regional heterogeneity. Consecutive sections from 43 prostates taken during autopsy representing fetuses (12-38 weeks of gestation), infants, prepubertal males and adults were double stained for chromogranin A and MIB-1. MIB-1 labeling index (LI) was calculated in the budding tips, forming acini, major collecting ducts, adjacent and non-adjacent stromal compartments. Furthermore, the topographic relationship between proliferating cells and NE cells was evaluated. In the first half of gestation, cell proliferation as revealed by MIB-1 LI was significantly higher in epithelial structures and stroma than in older fetuses and other age groups. MIB-1 LI was higher in budding tips than in other epithelial regions. MIB-1 LI in stroma adjacent to budding tips was not higher than that adjacent to other epithelial branching segments. Co-expression of chromogranin A and MIB-1 staining was not observed. MIB-1 LI was lower in cells in the direct vicinity of chromogranin A positive NE cells than at a distance from NE cells. Prostate development in the first half of gestation is explosive. Thereafter, the prostate basically is a slow-growing organ. Budding tips are the major growth foci during early prostate development, while stromal growth is evenly distributed throughout the prostate, probably indicating that stromal-epithelial interactions do not manifest in enhanced proliferation at their interface. NE cells may have an inhibitory effect on proliferation of exocrine epithelial cells and are probably only associated with differentiation of prostate exocrine cells in the prostate. Copyright 2001 Wiley-Liss, Inc.

TRIENNIAL LACTATION SYMPOSIUM/BOLFA: Plasticity of mammary development in the prepubertal bovine mammary gland.

PubMed

Akers, R M

2017-12-01

Although peripubertal mammary development represents only a small fraction of the total mass of mammary parenchyma present in the udder at the end of gestation and into lactation, there is increasing evidence that the tissue foundations created in early life can affect future mammary development and function. Studies on expression of estrogen and progesterone receptors seem to confirm the relevance of these steroids in prepubertal mammary development, but connections with other growth factors, hormones, and local tissue factors remain elusive. Enhanced preweaning feeding in the bovine appears to enhance the capacity of mammary tissue to response to mammogenic stimulation. This suggests the possibility that improved early nutrition might allow for creation of stem or progenitor cell populations to better support the massive ductal growth and lobulo-alveolar development during gestation. Increasing evidence that immune cells are involved in mammary development suggests there are unexpected and poorly understood connections between the immune system and mammary development. This is nearly unexplored in ruminants. Development of new tools to identify, isolate, and characterize cell populations within the developing bovine mammary gland offer the possibility of identifying and perhaps altering populations of mammary stem cells or selected progenitor cells to modulate mammary development and, possibly, mammary function.

Cell growth and differentiation on feeder layers is predicted to be influenced by bioreactor geometry.

PubMed

Peng, C A; Palsson, B Ø

1996-06-05

Tissue function is comprised of a complex interplay between biological and physicochemical rate processes. The design of bioreactors for tissue engineering must account for these processes simultaneously in order to obtain a bioreactor that provides a uniform environment for tissue growth and development. In the present study we consider the effects of fluid flow and mass transfer on the growth of a tissue in a parallel-plate bioreactor configuration. The parenchymal cells grow on a preformed stromal (feeder) layer that secretes a growth factor that stimulates parenchymal stem cell replication and differentiation. The biological dynamics are described by a unilineage model that describes the replication and differentiation of the tissue stem cell. The physicochemical rates are described by the Navier-Stokes and convective-diffusion equations. The model equations are solved by a finite element method. Two dimensionless groups govern the behavior of the solution. One is the Graetz number (Gz) that describes the relative rates of convection and diffusion, and the other a new dimensionless ratio (designated by P) that describes the interplay of the growth factor production, diffusion, and stimulation. Four geometries (slab, gondola, diamond, and radial shapes) for the parallel-plate bioreactor are analyzed. The uniformity of cell growth is measured by a two-dimensional coefficient of variance. The concentration distribution of the stroma-derived growth factor was computed first based on fluid flow and bioreactor geometry. Then the concomitant cell density distribution was obtained by integrating the calculated growth factor concentration with the parenchymal cell growth and unilineage differentiation process. The spatiotemporal cell growth patterns in four different bioreactor configurations were investigated under a variety of combinations of Gz (10(-1), 10(0), and 10(1)) and P(10(-2), 10(-1), 10(0), 10(1), and 10(2)). The results indicate high cell density and uniformity can be achieved for parameter values of P = 0.01, ..., 0.1 and Gz = 0.1, ..., 1.0. Among the four geometries investigated the radial-flow-type bioreactor provides the most uniform environment in which parenchymal cells can grow and differentiate ex vivo due to the absence of walls that are parallel to the flow paths creating slow flowing regions.

Downregulation of connective tissue growth factor inhibits the growth and invasion of gastric cancer cells and attenuates peritoneal dissemination

PubMed Central

2011-01-01

Background Connective tissue growth factor (CTGF) has been shown to be implicated in tumor development and progression. However, the role of CTGF in gastric cancer remains largely unknown. Results In this study, we showed that CTGF was highly expressed in gastric cancer tissues compared with matched normal gastric tissues. The CTGF expression in tumor tissue was associated with histologic grade, lymph node metastasis and peritoneal dissemination (P < 0.05). Patients with positive CTGF expression had significantly lower cumulative postoperative 5 year survival rate than those with negative CTGF expression (22.9% versus 48.1%, P < 0.001). We demonstrated that knockdown of CTGF expression significantly inhibited cell growth of gastric cancer cells and decreased cyclin D1 expression. Moreover, knockdown of CTGF expression also markedly reduced the migration and invasion of gastric cancer cells and decreased the expression of matrix metalloproteinase (MMP)-2 and MMP-9. Animal studies revealed that nude mice injected with the CTGF knockdown stable cell lines featured a smaller number of peritoneal seeding nodules than the control cell lines. Conclusions These data suggest that CTGF plays an important role in cell growth and invasion in human gastric cancer and it appears to be a potential prognostic marker for patients with gastric cancer. PMID:21955589

Downregulation of connective tissue growth factor inhibits the growth and invasion of gastric cancer cells and attenuates peritoneal dissemination.

PubMed

Jiang, Cheng-Gang; Lv, Ling; Liu, Fu-Rong; Wang, Zhen-Ning; Liu, Fu-Nan; Li, Yan-Shu; Wang, Chun-Yu; Zhang, Hong-Yan; Sun, Zhe; Xu, Hui-Mian

2011-09-28

Connective tissue growth factor (CTGF) has been shown to be implicated in tumor development and progression. However, the role of CTGF in gastric cancer remains largely unknown. In this study, we showed that CTGF was highly expressed in gastric cancer tissues compared with matched normal gastric tissues. The CTGF expression in tumor tissue was associated with histologic grade, lymph node metastasis and peritoneal dissemination (P < 0.05). Patients with positive CTGF expression had significantly lower cumulative postoperative 5 year survival rate than those with negative CTGF expression (22.9% versus 48.1%, P < 0.001). We demonstrated that knockdown of CTGF expression significantly inhibited cell growth of gastric cancer cells and decreased cyclin D1 expression. Moreover, knockdown of CTGF expression also markedly reduced the migration and invasion of gastric cancer cells and decreased the expression of matrix metalloproteinase (MMP)-2 and MMP-9. Animal studies revealed that nude mice injected with the CTGF knockdown stable cell lines featured a smaller number of peritoneal seeding nodules than the control cell lines. These data suggest that CTGF plays an important role in cell growth and invasion in human gastric cancer and it appears to be a potential prognostic marker for patients with gastric cancer.

Effect of respiratory syncytial virus on the growth of hepatocellular carcinoma cell-lines

PubMed Central

Choi, Song Hee; Park, Byoung Kwon; Lee, Keun-Wook; Chang, Jun; Lee, Younghee; Kwon, Hyung-Joo

2015-01-01

In several reports, the respiratory syncytial virus (RSV) was identified as an oncolytic virus in cancer cells (e.g., lung and prostate cancer). However, the effects of RSV in hepatocellular carcinoma (HCC) cells have not yet been investigated. Here, we observed the inhibitory effects of RSV infection in HCC cell-lines. Cell growth was significantly decreased by RSV infection in BNL-HCC, Hep3B, Huh-7 and SNU-739 cells. After RSV infection, plaque formation and syncytial formation were observed in affected Hep3B and Huh-7 cells. RSV protein-expression was also detected in Hep3B and Huh-7 cells; however, only Huh-7 cells showed apoptosis after RSV infection. Furthermore, inhibition of cell migration by RSV infection was observed in BNL-HCC, Hep3B, Huh-7 and SNU-739 cells. Therefore, further investigation is required to clarify the molecular mechanism of RSV-mediated inhibition of HCC cell growth, and to develop potential RSV oncolytic viro-therapeutics. [BMB Reports 2015; 48(10): 565-570] PMID:25739391

A Novel Counter Sheet-flow Sandwich Cell Culture Device for Mammalian Cell Growth in Space

NASA Astrophysics Data System (ADS)

Sun, Shujin; Gao, Yuxin; Shu, Nanjiang; Tang, Zemei; Tao, Zulai; Long, Mian

2008-08-01

Cell culture and growth in space is crucial to understand the cellular responses under microgravity. The effects of microgravity were coupled with such environment restrictions as medium perfusion, in which the underlying mechanism has been poorly understood. In the present work, a customer-made counter sheet-flow sandwich cell culture device was developed upon a biomechanical concept from fish gill breathing. The sandwich culture unit consists of two side chambers where the medium flow is counter-directional, a central chamber where the cells are cultured, and two porous polycarbonate membranes between side and central chambers. Flow dynamics analysis revealed the symmetrical velocity profile and uniform low shear rate distribution of flowing medium inside the central culture chamber, which promotes sufficient mass transport and nutrient supply for mammalian cell growth. An on-orbit experiment performed on a recovery satellite was used to validate the availability of the device.

Importance of the High-Expression of Proline Transporter PutP to the Adaptation of Escherichia coli to High Salinity.

PubMed

Sasaki, Hideaki; Sato, Daichi; Oshima, Akinobu

2017-01-01

　The effect of the amount of the proline transporter PutP expression on the mechanism of adaptation of E. coli cells to high salinity was analyzed. The PutP gene derived from the E. coli expression plasmid was introduced into the E. coli cell, and a high PutP expression strain was developed. At 1.2 M NaCl culture condition, the growth of normal E. coli cells was inhibited, whereas high ProP expression cells showed growth under 2.5 M NaCl conditions. The uptake of proline by E. coli as a compatible solute and substrate for metabolization was in good accordance with those seen in cell growth. These data suggested that the amount of the proline transporter PutP expression played an important role in the adaptation of E. coli cells to high saline conditions.

CD10/neutral endopeptidase 24.11 hydrolyzes bombesin-like peptides and regulates the growth of small cell carcinomas of the lung.

PubMed Central

Shipp, M A; Tarr, G E; Chen, C Y; Switzer, S N; Hersh, L B; Stein, H; Sunday, M E; Reinherz, E L

1991-01-01

Bombesin-like peptides are essential autocrine growth factors for many small cell carcinomas (SCCas) of the lung. Herein, we demonstrate that these malignant pulmonary neuroendocrine cells express low levels of the cell surface metalloendopeptidase CD10/neutral endopeptidase 24.11 (CD10/NEP, common acute lymphoblastic leukemia antigen) and that this enzyme hydrolyzes bombesin-like peptides. The growth of bombesin-like peptide-dependent SCC as is inhibited by CD10/NEP and potentiated by CD10/NEP inhibition. The results provide evidence that CD10/NEP is involved in the regulation of tumor cell proliferation. Since SCCa of the lung occurs almost exclusively in cigarette smokers and cigarette smoke inactivates CD10/NEP, decreased cell surface CD10/NEP enzymatic activity may be causally related to the development of SCCa of the lung. Images PMID:1660144

CD10/neutral endopeptidase 24.11 hydrolyzes bombesin-like peptides and regulates the growth of small cell carcinomas of the lung.

PubMed

Shipp, M A; Tarr, G E; Chen, C Y; Switzer, S N; Hersh, L B; Stein, H; Sunday, M E; Reinherz, E L

1991-12-01

Bombesin-like peptides are essential autocrine growth factors for many small cell carcinomas (SCCas) of the lung. Herein, we demonstrate that these malignant pulmonary neuroendocrine cells express low levels of the cell surface metalloendopeptidase CD10/neutral endopeptidase 24.11 (CD10/NEP, common acute lymphoblastic leukemia antigen) and that this enzyme hydrolyzes bombesin-like peptides. The growth of bombesin-like peptide-dependent SCC as is inhibited by CD10/NEP and potentiated by CD10/NEP inhibition. The results provide evidence that CD10/NEP is involved in the regulation of tumor cell proliferation. Since SCCa of the lung occurs almost exclusively in cigarette smokers and cigarette smoke inactivates CD10/NEP, decreased cell surface CD10/NEP enzymatic activity may be causally related to the development of SCCa of the lung.

ABA Suppresses Root Hair Growth via the OBP4 Transcriptional Regulator1[OPEN

PubMed Central

Kawamura, Ayako; Schäfer, Sabine; Breuer, Christian; Shibata, Michitaro; Mitsuda, Nobutaka; Ohme-Takagi, Masaru; Matsui, Minami

2017-01-01

Plants modify organ growth and tune morphogenesis in response to various endogenous and environmental cues. At the cellular level, organ growth is often adjusted by alterations in cell growth, but the molecular mechanisms underlying this control remain poorly understood. In this study, we identify the DNA BINDING WITH ONE FINGER (DOF)-type transcription regulator OBF BINDING PROTEIN4 (OBP4) as a repressor of cell growth. Ectopic expression of OBP4 in Arabidopsis (Arabidopsis thaliana) inhibits cell growth, resulting in severe dwarfism and the repression of genes involved in the regulation of water transport, root hair development, and stress responses. Among the basic helix-loop-helix transcription factors known to control root hair growth, OBP4 binds the ROOT HAIR DEFECTIVE6-LIKE2 (RSL2) promoter to repress its expression. The accumulation of OBP4 proteins is detected in expanding root epidermal cells, and its expression level is increased by the application of abscisic acid (ABA) at concentrations sufficient to inhibit root hair growth. ABA-dependent induction of OBP4 is associated with the reduced expression of RSL2. Furthermore, ectopic expression of OBP4 or loss of RSL2 function results in ABA-insensitive root hair growth. Taken together, our results suggest that OBP4-mediated transcriptional repression of RSL2 contributes to the ABA-dependent inhibition of root hair growth in Arabidopsis. PMID:28167701

Cell–scaffold interaction within engineered tissue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Haiping; Liu, Yuanyuan, E-mail: Yuanyuan_liu@shu.edu.cn; Jiang, Zhenglong

The structure of a tissue engineering scaffold plays an important role in modulating tissue growth. A novel gelatin–chitosan (Gel–Cs) scaffold with a unique structure produced by three-dimensional printing (3DP) technology combining with vacuum freeze-drying has been developed for tissue-engineering applications. The scaffold composed of overall construction, micro-pore, surface morphology, and effective mechanical property. Such a structure meets the essential design criteria of an ideal engineered scaffold. The favorable cell–matrix interaction supports the active biocompatibility of the structure. The structure is capable of supporting cell attachment and proliferation. Cells seeded into this structure tend to maintain phenotypic shape and secreted largemore » amounts of extracellular matrix (ECM) and the cell growth decreased the mechanical properties of scaffold. This novel biodegradable scaffold has potential applications for tissue engineering based upon its unique structure, which acts to support cell growth. - Highlights: • The scaffold is not only for providing a surface for cell residence but also for determining cell phenotype and retaining structural integrity. • The mechanical property of scaffold can be affected by activities of cell. • The scaffold provides a microenvironment for cell attachment, growth, and migration.« less

Development of an optimized tetracycline-inducible expression system to increase the accumulation of interleukin-10 in tobacco BY-2 suspension cells.

PubMed

Bortesi, Luisa; Rademacher, Thomas; Schiermeyer, Andreas; Schuster, Flora; Pezzotti, Mario; Schillberg, Stefan

2012-07-11

Plant cell suspension cultures can be used for the production of valuable pharmaceutical and industrial proteins. When the recombinant protein is secreted into the culture medium, restricting expression to a defined growth phase can improve both the quality and quantity of the recovered product by minimizing proteolytic activity. Temporal restriction is also useful for recombinant proteins whose constitutive expression affects cell growth and viability, such as viral interleukin-10 (vIL-10). We have developed a novel, tetracycline-inducible system suitable for tobacco BY-2 suspension cells which increases the yields of vIL-10. The new system is based on a binary vector that is easier to handle than conventional vectors, contains an enhanced inducible promoter and 5'-UTR to improve yields, and incorporates a constitutively-expressed visible marker gene to allow the rapid and straightforward selection of the most promising transformed clones. Stable transformation of BY-2 cells with this vector, without extensive optimization of the induction conditions, led to a 3.5 fold increase in vIL-10 levels compared to constitutive expression in the same host. We have developed an effective and straightforward molecular farming platform technology that improves both the quality and the quantity of recombinant proteins produced in plant cells, particularly those whose constitutive expression has a negative impact on plant growth and development. Although we tested the platform using vIL-10 produced in BY-2 cells, it can be applied to other host/product combinations and is also useful for basic research requiring strictly controlled transgene expression.

Synchronization of Somatic Embryogenesis in Date Palm Suspension Culture Using Abscisic Acid.

PubMed

Alwael, Hussain A; Naik, Poornananda M; Al-Khayri, Jameel M

2017-01-01

Somatic embryogenesis is considered the most effective method for commercial propagation of date palm. However, the limitation of obtaining synchronized development of somatic embryos remains an impediment. The synchronization of somatic embryo development is ideal for the applications to produce artificial seeds. Abscisic acid (ABA) is associated with stress response and influences in vitro growth and development. This chapter describes an effective method to achieve synchronized development of somatic embryos in date palm cell suspension culture. Among the ABA concentrations tested (0, 1, 10, 50, 100 μM), the best synchronized growth was obtained in response to 50-100 μM. Here we provide a comprehensive protocol for in vitro plant regeneration of date palm starting with shoot-tip explant, callus initiation and growth, cell suspension establishment, embryogenesis synchronization with ABA treatment, somatic embryo germination, and rooting as well as acclimatized plantlet establishment.

Biochemical characterization of a new maize (Zea mays L.) peptide growth factor.

PubMed

Rodríguez-López, Cesar David; Rodríguez-Romero, Adela; Aguilar, Raúl; de Jiménez, Estela Sánchez

2011-01-01

Coordination of cell growth and cell division is very important for living organisms in order for these to develop harmonically. The present research is concerned with the purification and characterization of a new peptide hormone, namely ZmIGF (Zea mays insulin-like growth factor), which regulates growth and cell division in maize tissues. ZmIGF is a peptide of 5.7 kDa, as determined by mass spectroscopy. It was isolated either from maize embryonic axes of 48-h germinated seeds or from embryogenic callus and purified through several chromatographic procedures to obtain a single peak as shown by Reverse Phase High-Performance Liquid Chromatography (RP-HPLC). This peptide exhibits a well defined α-helix structure by circular dichroism analysis, similar to that reported for Insulin or for Insulin-like growth factor (IGF-1). Further, ZmIGF seems to perform, in maize, a similar function to that reported for insulin or peptides from the IGF family in animals. Indeed, maize tissues stimulated either by ZmIGF or insulin showed to induce selective synthesis of ribosomal proteins as well as of DNA. Taken together, the previously mentioned data strongly suggest that plants contain a peptide hormone of the IGF family, highly conserved through evolution that regulates growth and development.

The combined effects of real or simulated microgravity and red-light photoactivation on plant root meristematic cells.

PubMed

Valbuena, Miguel A; Manzano, Aránzazu; Vandenbrink, Joshua P; Pereda-Loth, Veronica; Carnero-Diaz, Eugénie; Edelmann, Richard E; Kiss, John Z; Herranz, Raúl; Medina, F Javier

2018-06-08

Red light is able to compensate for deleterious effects of microgravity on root cell growth and proliferation. Partial gravity combined with red light produces differential signals during the early plant development. Light and gravity are environmental cues used by plants throughout evolution to guide their development. We have investigated the cross-talk between phototropism and gravitropism under altered gravity in space. The focus was on the effects on the meristematic balance between cell growth and proliferation, which is disrupted under microgravity in the dark. In our spaceflight experiments, seedlings of three Arabidopsis thaliana genotypes, namely the wild type and mutants of phytochrome A and B, were grown for 6 days, including red-light photoactivation for the last 2 days. Apart from the microgravity and the 1g on-board control conditions, fractional gravity (nominally 0.1g, 0.3g, and 0.5g) was created with on-board centrifuges. In addition, a simulated microgravity (random positioning machine, RPM) experiment was performed on ground, including both dark-grown and photostimulated samples. Photoactivated samples in spaceflight and RPM experiments showed an increase in the root length consistent with phototropic response to red light, but, as gravity increased, a gradual decrease in this response was observed. Uncoupling of cell growth and proliferation was detected under microgravity in darkness by transcriptomic and microscopic methods, but red-light photoactivation produced a significant reversion. In contrast, the combination of red light and partial gravity produced small but consistent variations in the molecular markers of cell growth and proliferation, suggesting an antagonistic effect between light and gravity signals at the early plant development. Understanding these parameters of plant growth and development in microgravity will be important as bioregenerative life support systems for the colonization of the Moon and Mars.

Protein Biomarkers Associated With Growth And Synaptogenesis In a cell culture model of neuronal development

EPA Science Inventory

Cerebellar granule cells (CGC) provide a homogenous population of cells which can be used as an in vitro model for studying the cellular processes involved in the normal development of the CNS. They may also be useful for hazard identification as in vitro screens fo...