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Sample records for cycle arrest death

  1. Parvovirus infection-induced cell death and cell cycle arrest

    PubMed Central

    Chen, Aaron Yun; Qiu, Jianming

    2011-01-01

    The cytopathic effects induced during parvovirus infection have been widely documented. Parvovirus infection-induced cell death is often directly associated with disease outcomes (e.g., anemia resulting from loss of erythroid progenitors during parvovirus B19 infection). Apoptosis is the major form of cell death induced by parvovirus infection. However, nonapoptotic cell death, namely necrosis, has also been reported during infection of the minute virus of mice, parvovirus H-1 and bovine parvovirus. Recent studies have revealed multiple mechanisms underlying the cell death during parvovirus infection. These mechanisms vary in different parvoviruses, although the large nonstructural protein (NS)1 and the small NS proteins (e.g., the 11 kDa of parvovirus B19), as well as replication of the viral genome, are responsible for causing infection-induced cell death. Cell cycle arrest is also common, and contributes to the cytopathic effects induced during parvovirus infection. While viral NS proteins have been indicated to induce cell cycle arrest, increasing evidence suggests that a cellular DNA damage response triggered by an invading single-stranded parvoviral genome is the major inducer of cell cycle arrest in parvovirus-infected cells. Apparently, in response to infection, cell death and cell cycle arrest of parvovirus-infected cells are beneficial to the viral cell lifecycle (e.g., viral DNA replication and virus egress). In this article, we will discuss recent advances in the understanding of the mechanisms underlying parvovirus infection-induced cell death and cell cycle arrest. PMID:21331319

  2. Mitochondrial Uncoupling Protein 2 Induces Cell Cycle Arrest and Necrotic Cell Death

    PubMed Central

    Palanisamy, Arun P.; Cheng, Gang; Sutter, Alton G.; Evans, Zachary P.; Polito, Carmen C.; Jin, Lan; Liu, John; Schmidt, Michael G.

    2014-01-01

    Abstract Uncoupling protein 2 (UCP2) is a mitochondrial membrane protein that regulates energy metabolism and reactive oxygen species (ROS) production. We generated mouse carboxy- and amino-terminal green fluorescent protein (GFP)-tagged UCP2 constructs to investigate the effect of UCP2 expression on cell proliferation and viability. UCP2-transfected Hepa 1–6 cells did not show reduced cellular adenosine triphosphate (ATP) but showed increased levels of glutathione. Flow cytometry analysis indicated that transfected cells were less proliferative than nontransfected controls, with most cells blocked at the G1 phase. The effect of UCP2 on cell cycle arrest could not be reversed by providing exogenous ATP or oxidant supply, and was not affected by the chemical uncoupler carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP). However, this effect of UCP2 was augmented by treatment with genistein, a tyrosine kinase inhibitor, which by itself did not affect cell proliferation on control hepatocytes. Western blotting analysis revealed decreased expression levels of CDK6 but not CDK2 and D-type cyclins. Examination of cell viability in UCP2-transfected cells with Trypan Blue and Annexin-V staining revealed that UCP2 transfection led to significantly increased cell death. However, characteristics of apoptosis were absent in UCP2-transfected Hepa 1–6 cells, including lack of oligonucleosomal fragmentation (laddering) of chromosomal DNA, release of cytochrome c from mitochondria, and cleavage of caspase-3. In conclusion, our results indicate that UCP2 induces cell cycle arrest at G1 phase and causes nonapoptotic cell death, suggesting that UCP2 may act as a powerful influence on hepatic regeneration and cell death in the steatotic liver. PMID:24320727

  3. Cypermethrin Induces Macrophages Death through Cell Cycle Arrest and Oxidative Stress-Mediated JNK/ERK Signaling Regulated Apoptosis

    PubMed Central

    Huang, Fang; Liu, Qiaoyun; Xie, Shujun; Xu, Jian; Huang, Bo; Wu, Yihua; Xia, Dajing

    2016-01-01

    Cypermethrin is one of the most highly effective synthetic pyrethroid insecticides. The toxicity of cypermethrin to the reproductive and nervous systems has been well studied. However, little is known about the toxic effect of cypermethrin on immune cells such as macrophages. Here, we investigated the cytotoxicity of cypermethrin on macrophages and the underlying molecular mechanisms. We found that cypermethrin reduced cell viability and induced apoptosis in RAW 264.7 cells. Cypermethrin also increased reactive oxygen species (ROS) production and DNA damage in a dose-dependent manner. Moreover, cypermethrin-induced G1 cell cycle arrest was associated with an enhanced expression of p21, wild-type p53, and down-regulation of cyclin D1, cyclin E and CDK4. In addition, cypermethrin treatment activated MAPK signal pathways by inducing c-Jun N-terminal kinase (JNK) and extracellular regulated protein kinases 1/2 ERK1/2 phosphorylation, and increased the cleaved poly ADP-ribose polymerase (PARP). Further, pretreatment with antioxidant N-acetylcysteine (NAC) effectively abrogated cypermethrin-induced cell cytotoxicity, G1 cell cycle arrest, DNA damage, PARP activity, and JNK and ERK1/2 activation. The specific JNK inhibitor (SP600125) and ERK1/2 inhibitor (PD98059) effectively reversed the phosphorylation level of JNK and ERK1/2, and attenuated the apoptosis. Taken together, these data suggested that cypermethrin caused immune cell death via inducing cell cycle arrest and apoptosis regulated by ROS-mediated JNK/ERK pathway. PMID:27322250

  4. Cypermethrin Induces Macrophages Death through Cell Cycle Arrest and Oxidative Stress-Mediated JNK/ERK Signaling Regulated Apoptosis.

    PubMed

    Huang, Fang; Liu, Qiaoyun; Xie, Shujun; Xu, Jian; Huang, Bo; Wu, Yihua; Xia, Dajing

    2016-01-01

    Cypermethrin is one of the most highly effective synthetic pyrethroid insecticides. The toxicity of cypermethrin to the reproductive and nervous systems has been well studied. However, little is known about the toxic effect of cypermethrin on immune cells such as macrophages. Here, we investigated the cytotoxicity of cypermethrin on macrophages and the underlying molecular mechanisms. We found that cypermethrin reduced cell viability and induced apoptosis in RAW 264.7 cells. Cypermethrin also increased reactive oxygen species (ROS) production and DNA damage in a dose-dependent manner. Moreover, cypermethrin-induced G1 cell cycle arrest was associated with an enhanced expression of p21, wild-type p53, and down-regulation of cyclin D1, cyclin E and CDK4. In addition, cypermethrin treatment activated MAPK signal pathways by inducing c-Jun N-terminal kinase (JNK) and extracellular regulated protein kinases 1/2 ERK1/2 phosphorylation, and increased the cleaved poly ADP-ribose polymerase (PARP). Further, pretreatment with antioxidant N-acetylcysteine (NAC) effectively abrogated cypermethrin-induced cell cytotoxicity, G1 cell cycle arrest, DNA damage, PARP activity, and JNK and ERK1/2 activation. The specific JNK inhibitor (SP600125) and ERK1/2 inhibitor (PD98059) effectively reversed the phosphorylation level of JNK and ERK1/2, and attenuated the apoptosis. Taken together, these data suggested that cypermethrin caused immune cell death via inducing cell cycle arrest and apoptosis regulated by ROS-mediated JNK/ERK pathway. PMID:27322250

  5. SB225002 Induces Cell Death and Cell Cycle Arrest in Acute Lymphoblastic Leukemia Cells through the Activation of GLIPR1

    PubMed Central

    Leal, Paulo C.; Bhasin, Manoj K.; Zenatti, Priscila Pini; Nunes, Ricardo J.; Yunes, Rosendo A.; Nowill, Alexandre E.; Libermann, Towia A.; Zerbini, Luiz Fernando; Yunes, José Andrés

    2015-01-01

    Acute Lymphoblastic Leukemia (ALL) is the most frequent childhood malignancy. In the effort to find new anti-leukemic agents, we evaluated the small drug SB225002 (N-(2-hydroxy-4-nitrophenyl)-N’-(2-bromophenyl)urea). Although initially described as a selective antagonist of CXCR2, later studies have identified other cellular targets for SB225002, with potential medicinal use in cancer. We found that SB225002 has a significant pro-apoptotic effect against both B- and T-ALL cell lines. Cell cycle analysis demonstrated that treatment with SB225002 induces G2-M cell cycle arrest. Transcriptional profiling revealed that SB225002-mediated apoptosis triggered a transcriptional program typical of tubulin binding agents. Network analysis revealed the activation of genes linked to the JUN and p53 pathways and inhibition of genes linked to the TNF pathway. Early cellular effects activated by SB225002 included the up-regulation of GLIPR1, a p53-target gene shown to have pro-apoptotic activities in prostate and bladder cancer. Silencing of GLIPR1 in B- and T-ALL cell lines resulted in increased resistance to SB225002. Although SB225002 promoted ROS increase in ALL cells, antioxidant N-Acetyl Cysteine pre-treatment only modestly attenuated cell death, implying that the pro-apoptotic effects of SB225002 are not exclusively mediated by ROS. Moreover, GLIPR1 silencing resulted in increased ROS levels both in untreated and SB225002-treated cells. In conclusion, SB225002 induces cell cycle arrest and apoptosis in different B- and T-ALL cell lines. Inhibition of tubulin function with concurrent activation of the p53 pathway, in particular, its downstream target GLIPR1, seems to underlie the anti-leukemic effect of SB225002. PMID:26302043

  6. SB225002 Induces Cell Death and Cell Cycle Arrest in Acute Lymphoblastic Leukemia Cells through the Activation of GLIPR1.

    PubMed

    de Vasconcellos, Jaíra Ferreira; Laranjeira, Angelo Brunelli Albertoni; Leal, Paulo C; Bhasin, Manoj K; Zenatti, Priscila Pini; Nunes, Ricardo J; Yunes, Rosendo A; Nowill, Alexandre E; Libermann, Towia A; Zerbini, Luiz Fernando; Yunes, José Andrés

    2015-01-01

    Acute Lymphoblastic Leukemia (ALL) is the most frequent childhood malignancy. In the effort to find new anti-leukemic agents, we evaluated the small drug SB225002 (N-(2-hydroxy-4-nitrophenyl)-N'-(2-bromophenyl)urea). Although initially described as a selective antagonist of CXCR2, later studies have identified other cellular targets for SB225002, with potential medicinal use in cancer. We found that SB225002 has a significant pro-apoptotic effect against both B- and T-ALL cell lines. Cell cycle analysis demonstrated that treatment with SB225002 induces G2-M cell cycle arrest. Transcriptional profiling revealed that SB225002-mediated apoptosis triggered a transcriptional program typical of tubulin binding agents. Network analysis revealed the activation of genes linked to the JUN and p53 pathways and inhibition of genes linked to the TNF pathway. Early cellular effects activated by SB225002 included the up-regulation of GLIPR1, a p53-target gene shown to have pro-apoptotic activities in prostate and bladder cancer. Silencing of GLIPR1 in B- and T-ALL cell lines resulted in increased resistance to SB225002. Although SB225002 promoted ROS increase in ALL cells, antioxidant N-Acetyl Cysteine pre-treatment only modestly attenuated cell death, implying that the pro-apoptotic effects of SB225002 are not exclusively mediated by ROS. Moreover, GLIPR1 silencing resulted in increased ROS levels both in untreated and SB225002-treated cells. In conclusion, SB225002 induces cell cycle arrest and apoptosis in different B- and T-ALL cell lines. Inhibition of tubulin function with concurrent activation of the p53 pathway, in particular, its downstream target GLIPR1, seems to underlie the anti-leukemic effect of SB225002. PMID:26302043

  7. Latexin sensitizes leukemogenic cells to gamma-irradiation-induced cell-cycle arrest and cell death through Rps3 pathway.

    PubMed

    You, Y; Wen, R; Pathak, R; Li, A; Li, W; St Clair, D; Hauer-Jensen, M; Zhou, D; Liang, Y

    2014-01-01

    Leukemia is a leading cause of cancer death. Recently, the latexin (Lxn) gene was identified as a potential tumor suppressor in several types of solid tumors and lymphoma, and Lxn expression was found to be absent or downregulated in leukemic cells. Whether Lxn functions as a tumor suppressor in leukemia and what molecular and cellular mechanisms are involved are unknown. In this study, the myeloid leukemogenic FDC-P1 cell line was used as a model system and Lxn was ectopically expressed in these cells. Using the protein pull-down assay and mass spectrometry, ribosomal protein subunit 3 (Rps3) was identified as a novel Lxn binding protein. Ectopic expression of Lxn inhibited FDC-P1 growth in vitro. More surprisingly, Lxn enhanced gamma irradiation-induced DNA damages and induced cell-cycle arrest and massive necrosis, leading to depletion of FDC-P1 cells. Mechanistically, Lxn inhibited the nuclear translocation of Rps3 upon radiation, resulting in abnormal mitotic spindle formation and chromosome instability. Rps3 knockdown increased the radiation sensitivity of FDC-P1, confirming that the mechanism of action of Lxn is mediated by Rps3 pathway. Moreover, Lxn enhanced the cytotoxicity of chemotherapeutic agent, VP-16, on FDC-P1 cells. Our study suggests that Lxn itself not only suppresses leukemic cell growth but also potentiates the cytotoxic effect of radio- and chemotherapy on cancer cells. Lxn could be a novel molecular target that improves the efficacy of anti-cancer therapy. PMID:25341047

  8. TSG101 Silencing Suppresses Hepatocellular Carcinoma Cell Growth by Inducing Cell Cycle Arrest and Autophagic Cell Death

    PubMed Central

    Shao, Zhuo; Ji, Weiping; Liu, Anan; Qin, Ancheng; Shen, Li; Li, Gang; Zhou, Yinqi; Hu, Xiangui; Yu, Enda; Jin, Gang

    2015-01-01

    Background The tumor susceptibility gene 101 (TSG101) was originally identified as a tumor-suppressor gene that mediates many molecular and biological processes, such as ubiquitination, endosomal trafficking, cell survival, and virus budding, but its role in hepatocellular carcinoma (HCC) is currently unknown. Material/Methods We assessed the expression of TSG101 in HCC and paracancerous tissues using qPCR. Then, we used the TSG101-specific siRNA mix to disrupt the expression of TSG101 to investigate the subsequent effect on human hepatoma-7 (Huh7) cells. Western blot was used to detect the protein expression of TSG101 and other molecules. Cell growth assay was performed using CCK8. Transwell assay was used to investigate the migration and invasion ability of Huh7 cells after transfection with of TSG101 siRNA. Flow cytometry was used to estimate the effect of TSG101 knockdown on cell cycle and apoptosis. Confocal laser scanning microscopy was used to observe the actin filaments change and the formation of autophagy. Results TSG101 was over-expressed in HCC tissues. TSG101 silence was able to suppress Huh7 cell proliferation, migration, and invasion. Furthermore, silencing of TSG101 could induce cell cycle arrest at G1 phase and inhibit the expression of cyclin A and cyclin D, while up-regulating the expression of CDK2. The mechanism might be induction of autophagic cell death and inactivation of Akt and ERK1/2. Conclusions TSG101 plays an important role in the development of HCC and may be a target for molecular therapy. PMID:26537625

  9. Inorganic Pyrophosphatase Defects Lead to Cell Cycle Arrest and Autophagic Cell Death through NAD+ Depletion in Fermenting Yeast*

    PubMed Central

    Serrano-Bueno, Gloria; Hernández, Agustín; López-Lluch, Guillermo; Pérez-Castiñeira, José Román; Navas, Plácido; Serrano, Aurelio

    2013-01-01

    Inorganic pyrophosphatases are required for anabolism to take place in all living organisms. Defects in genes encoding these hydrolytic enzymes are considered inviable, although their exact nature has not been studied at the cellular and molecular physiology levels. Using a conditional mutant in IPP1, the Saccharomyces cerevisiae gene encoding the cytosolic soluble pyrophosphatase, we show that respiring cells arrest in S phase upon Ipp1p deficiency, but they remain viable and resume growth if accumulated pyrophosphate is removed. However, fermenting cells arrest in G1/G0 phase and suffer massive vacuolization and eventual cell death by autophagy. Impaired NAD+ metabolism is a major determinant of cell death in this scenario because demise can be avoided under conditions favoring accumulation of the oxidized pyridine coenzyme. These results posit that the mechanisms related to excess pyrophosphate toxicity in eukaryotes are dependent on the energy metabolism of the cell. PMID:23479727

  10. Podophyllotoxin acetate triggers anticancer effects against non-small cell lung cancer cells by promoting cell death via cell cycle arrest, ER stress and autophagy

    PubMed Central

    CHOI, JAE YEON; HONG, WAN GI; CHO, JEONG HYUN; KIM, EUN MI; KIM, JONGDOO; JUNG, CHAN-HUN; HWANG, SANG-GU; UM, HONG-DUCK; PARK, JONG KUK

    2015-01-01

    We previously reported that podophyllotoxin acetate (PA) radiosensitizes NCI-H460 cells. Here, we confirmed that PA treatment also induces cell death among two other non-small cell lung cancer (NSCLC) cell lines: NCI-H1299 and A549 cells (IC50 values = 7.6 and 16.1 nM, respectively). Our experiments further showed that PA treatment was able to induce cell death via various mechanisms. First, PA dose-dependently induced cell cycle arrest at G2/M phase, as shown by accumulation of the mitosis-related proteins, p21, survivin and Aurora B. This G2/M phase arrest was due to the PA-induced inhibition of microtubule polymerization. Together, the decreased microtubule polymerization and increased cell cycle arrest induced DNA damage (reflected by accumulation of γ-H2AX) and triggered the induction of intrinsic and extrinsic apoptotic pathways, as shown by the time-dependent activations of caspase-3, -8 and -9. Second, PA time-dependently activated the pro-apoptotic ER stress pathway, as evidenced by increased expression levels of BiP, CHOP, IRE1-α, phospho-PERK, and phospho-JNK. Third, PA activated autophagy, as reflected by time-dependent increases in the expression levels of beclin-1, Atg3, Atg5 and Atg7, and the cleavage of LC3. Collectively, these results suggest a model wherein PA decreases microtubule polymerization and increases cell cycle arrest, thereby inducing apoptotic cell death via the activation of DNA damage, ER stress and autophagy. PMID:26314270

  11. Gene copy number and cell cycle arrest

    NASA Astrophysics Data System (ADS)

    Ghosh, Bhaswar; Bose, Indrani

    2006-03-01

    The cell cycle is an orderly sequence of events which ultimately lead to the division of a single cell into two daughter cells. In the case of DNA damage by radiation or chemicals, the damage checkpoints in the G1 and G2 phases of the cell cycle are activated. This results in an arrest of the cell cycle so that the DNA damage can be repaired. Once this is done, the cell continues with its usual cycle of activity. We study a mathematical model of the DNA damage checkpoint in the G2 phase which arrests the transition from the G2 to the M (mitotic) phase of the cell cycle. The tumor suppressor protein p53 plays a key role in activating the pathways leading to cell cycle arrest in mammalian systems. If the DNA damage is severe, the p53 proteins activate other pathways which bring about apoptosis, i.e., programmed cell death. Loss of the p53 gene results in the proliferation of cells containing damaged DNA, i.e., in the growth of tumors which may ultimately become cancerous. There is some recent experimental evidence which suggests that the mutation of a single copy of the p53 gene (in the normal cell each gene has two identical copies) is sufficient to trigger the formation of tumors. We study the effect of reducing the gene copy number of the p53 and two other genes on cell cycle arrest and obtain results consistent with experimental observations.

  12. Targeting TRPM2 Channels Impairs Radiation-Induced Cell Cycle Arrest and Fosters Cell Death of T Cell Leukemia Cells in a Bcl-2-Dependent Manner

    PubMed Central

    Klumpp, Dominik; Misovic, Milan; Szteyn, Kalina; Shumilina, Ekaterina; Rudner, Justine; Huber, Stephan M.

    2016-01-01

    Messenger RNA data of lymphohematopoietic cancer lines suggest a correlation between expression of the cation channel TRPM2 and the antiapoptotic protein Bcl-2. The latter is overexpressed in various tumor entities and mediates therapy resistance. Here, we analyzed the crosstalk between Bcl-2 and TRPM2 channels in T cell leukemia cells during oxidative stress as conferred by ionizing radiation (IR). To this end, the effects of TRPM2 inhibition or knock-down on plasma membrane currents, Ca2+ signaling, mitochondrial superoxide anion formation, and cell cycle progression were compared between irradiated (0–10 Gy) Bcl-2-overexpressing and empty vector-transfected Jurkat cells. As a result, IR stimulated a TRPM2-mediated Ca2+-entry, which was higher in Bcl-2-overexpressing than in control cells and which contributed to IR-induced G2/M cell cycle arrest. TRPM2 inhibition induced a release from G2/M arrest resulting in cell death. Collectively, this data suggests a pivotal function of TRPM2 in the DNA damage response of T cell leukemia cells. Apoptosis-resistant Bcl-2-overexpressing cells even can afford higher TRPM2 activity without risking a hazardous Ca2+-overload-induced mitochondrial superoxide anion formation. PMID:26839633

  13. Wig-1 regulates cell cycle arrest and cell death through the p53 targets FAS and 14-3-3σ

    PubMed Central

    Bersani, C; Xu, L-D; Vilborg, A; Lui, W-O; Wiman, K G

    2014-01-01

    Wig-1, also known as ZMAT3, is a p53 target gene that encodes an RNA-binding zinc-finger protein involved in the regulation of mRNA stability through binding to AU-rich elements (AREs). We have used microarray analysis to identify novel Wig-1 target mRNAs. We identified 2447 transcripts with >fourfold differential expression between Wig-1 and control small interfering (si)RNA-treated HCT116 cells. Several p53 target genes were among the deregulated transcripts. We found that Wig-1 regulates FAS and 14-3-3σ mRNA independently of p53. We show that Wig-1 binds to FAS mRNA 3′-UTR and decreases its stability through an ARE in the 3′-UTR. Depletion of Wig-1 was associated with increased cell death and reduced cell cycle arrest upon DNA damage. Our results suggest a role of Wig-1 as a survival factor that directs the p53 stress response toward cell cycle arrest rather than apoptosis through the regulation of FAS and 14-3-3σ mRNA levels. PMID:24469038

  14. Induction of P3NS1 Myeloma Cell Death and Cell Cycle Arrest by Simvastatin and/or γ-Radiation.

    PubMed

    Abdelrahman, Ibrahim Y; Helwa, Reham; Elkashef, Hausein; Hassan, Nagwa H A

    2015-01-01

    The present study was conducted to investigate the effect of γ-radiation alone or combined with a cytotoxic drug, simvastatin, on viability and cell cycling of a myeloma cell line. P3NS1 myeloma cells were treated with the selected dose of simvastatin (0.1 μM/l) 24 hours prior to γ-irradiation (0.25, 0.5 and 1 Gy). The cell viability, induction of apoptosis, cell death, cell cycling, generation of ROS, and expression of P53, Bax, Bcl2, caspase3, PARP1 and Fas genes were estimated. The results indicated that simvastatin (0.1 μM/l) treatment for 24 hours prior to γ- irradiation increased cell death to 37.5% as compared to 4.81% by radiation (0.5 Gy) alone. It was found that simvastatin treatment before irradiation caused arrest of cells in G0/G1 and G2/M phases as assessed using flow cytometry. Interestingly, simvastatin treatment of P3NS1 cells increased the intracellular ROS production and decreased antioxidant enzyme activity with increased P53, Bax and Caspase3 gene expression while that of Bcl2 was decreased. Consequently, our results indicated that pre-treatment with simvastatin increased radio sensitivity of myeloma tumor cells in addition to apoptotic effects through an intrinsic mitochondrial pathway. PMID:26514497

  15. Leptospermum flavescens Constituent-LF1 Causes Cell Death through the Induction of Cell Cycle Arrest and Apoptosis in Human Lung Carcinoma Cells

    PubMed Central

    Navanesan, Suerialoasan; Abdul Wahab, Norhanom; Manickam, Sugumaran; Sim, Kae Shin

    2015-01-01

    Leptospermum flavescens Sm. (Myrtaceae), locally known as ‘Senna makki’ is a smallish tree that is widespread and recorded to naturally occur in the montane regions above 900 m a.s.l from Burma to Australia. Although the species is recorded to be used traditionally to treat various ailments, there is limited data on biological and chemical investigations of L. flavescens. The aim of the present study was to investigate and understand the ability of L. flavescens in inducing cell death in lung cancer cells. The cytotoxic potentials of the extraction yields (methanol, hexane, ethyl acetate and water extracts as wells as a semi pure fraction, LF1) were evaluated against two human non-small cell lung carcinoma cell lines (A549 and NCI-H1299) using the MTT assay. LF1 showed the greatest cytotoxic effect against both cell lines with IC50 values of 7.12 ± 0.07 and 9.62 ± 0.50 μg/ml respectively. LF1 treated cells showed a sub-G1 region in the cell cycle analysis and also caused the presence of apoptotic morphologies in cells stained with acridine orange and ethidium bromide. Treatment with LF1 manifested an apoptotic population in cells that were evaluated using the Annexin V/ propidium iodide assay. Increasing dosage of LF1 caused a rise in the presence of activated caspase-3 enzymes in treated cells. Blockage of cell cycle progression was also observed in LF1-treated cells. These findings suggest that LF1 induces apoptosis and cell cycle arrest in treated lung cancer cells. Further studies are being conducted to isolate and identify the active compound as well to better understand the mechanism involved in inducing cell death. PMID:26287817

  16. Phthalocyanine-mediated photodynamic therapy induces cell death and a G /G{sub 1} cell cycle arrest in cervical cancer cells

    SciTech Connect

    Haywood-Small, S.L. . E-mail: s.l.hankin@sheffield.ac.uk; Vernon, D.I.; Griffiths, J.; Schofield, J.; Brown, S.B.

    2006-01-13

    We have developed a series of novel photosensitizers which have potential for anticancer photodynamic therapy (PDT). Photosensitizers include zinc phthalocyanine tetra-sulphonic acid and a family of derivatives with amino acid substituents of varying alkyl chain length and degree of branching. Subcellular localization of these photosensitizers at the phototoxic IC{sub 5} concentration in human cervical carcinoma cells (SiHa Cells) was similar to that of the lysosomal dye Lucifer Yellow. Subsequent nuclear relocalization was observed following irradiation with 665 nm laser light. The PDT response was characterized using the Sulforhodamine B cytotoxicity assay. Flow cytometry was used for both DNA cell cycle and dual Annexin V-FITC/propidium iodide analysis. Phototoxicity of the derivatives was of the same order of magnitude as for tetrasulphonated phthalocyanine but with an overall trend of increased phototoxicity with increasing amino acid chain length. Our results demonstrate cell death, inhibition of cell growth, and G /G{sub 1} cell cycle arrest during the phthalocyanine PDT-mediated response.

  17. Achyranthes aspera Root Extracts Induce Human Colon Cancer Cell (COLO-205) Death by Triggering the Mitochondrial Apoptosis Pathway and S Phase Cell Cycle Arrest

    PubMed Central

    Arora, Shagun; Tandon, Simran

    2014-01-01

    Achyranthes aspera (AA) has been used traditionally for the cure of various disorders. However, the action of root extracts of AA as anticancer agent and its cellular mechanism remain unclear. The aim was to screen the antitumor effect of ethanolic (EAA) and aqueous (AAA) root extracts on the growth of colon cancer COLO-205 cells by testing their cytotoxicity, followed by their effect on clonogenicity, migration, and induction of apoptosis. Mechanisms leading to apoptosis and cell cycle arrest were also investigated by expression studies of caspase-9, caspase-3, Bax, Bcl-2, p16, p21, and p27 genes, followed by flow cytometric analysis for cell cycle distribution. Cytotoxicity screening of AA extracts indicated greater cytotoxic activity of AAA extract against COLO-205 cells. A series of events marked by apoptosis revealed loss of cell viability, chromatin condensation, and DNA fragmentation in AAA treated cells to a greater extent. The mRNA expression levels of caspase-9, caspase-3, Bax, p16, p21, and p27 were markedly increased in the AAA treated cells, along with decreased Bcl-2 expression. The cell cycle arrest at S phase was detected by flow cytometric analysis after treatment with AAA. Overall the study signifies the aqueous extracts as a promising therapeutic candidate against cancer. PMID:25401123

  18. Synchronized Cell Cycle Arrest Promotes Osteoclast Differentiation.

    PubMed

    Kwon, Minsuk; Kim, Jin-Man; Lee, Kyunghee; Park, So-Young; Lim, Hyun-Sook; Kim, Taesoo; Jeong, Daewon

    2016-01-01

    Osteoclast progenitors undergo cell cycle arrest before differentiation into osteoclasts, induced by exposure to macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor-κB ligand (RANKL). The role of such cell cycle arrest in osteoclast differentiation has remained unclear, however. We here examined the effect of synchronized cell cycle arrest on osteoclast formation. Osteoclast progenitors deprived of M-CSF in culture adopted a uniform morphology and exhibited cell cycle arrest at the G₀-G₁ phase in association with both down-regulation of cyclins A and D1 as well as up-regulation of the cyclin-dependent kinase inhibitor p27(Kip1). Such M-CSF deprivation also promoted the differentiation of osteoclast progenitors into multinucleated osteoclasts expressing high levels of osteoclast marker proteins such as NFATc1, c-Fos, Atp6v0d2, cathepsin K, and integrin β3 on subsequent exposure to M-CSF and RANKL. Our results suggest that synchronized arrest and reprogramming of osteoclast progenitors renders them poised to respond to inducers of osteoclast formation. Further characterization of such effects may facilitate induction of the differentiation of heterogeneous and multipotent cells into desired cell lineages. PMID:27517906

  19. Synchronized Cell Cycle Arrest Promotes Osteoclast Differentiation

    PubMed Central

    Kwon, Minsuk; Kim, Jin-Man; Lee, Kyunghee; Park, So-Young; Lim, Hyun-Sook; Kim, Taesoo; Jeong, Daewon

    2016-01-01

    Osteoclast progenitors undergo cell cycle arrest before differentiation into osteoclasts, induced by exposure to macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor-κB ligand (RANKL). The role of such cell cycle arrest in osteoclast differentiation has remained unclear, however. We here examined the effect of synchronized cell cycle arrest on osteoclast formation. Osteoclast progenitors deprived of M-CSF in culture adopted a uniform morphology and exhibited cell cycle arrest at the G0–G1 phase in association with both down-regulation of cyclins A and D1 as well as up-regulation of the cyclin-dependent kinase inhibitor p27Kip1. Such M-CSF deprivation also promoted the differentiation of osteoclast progenitors into multinucleated osteoclasts expressing high levels of osteoclast marker proteins such as NFATc1, c-Fos, Atp6v0d2, cathepsin K, and integrin β3 on subsequent exposure to M-CSF and RANKL. Our results suggest that synchronized arrest and reprogramming of osteoclast progenitors renders them poised to respond to inducers of osteoclast formation. Further characterization of such effects may facilitate induction of the differentiation of heterogeneous and multipotent cells into desired cell lineages. PMID:27517906

  20. 17{alpha}-Estradiol arrests cell cycle progression at G{sub 2}/M and induces apoptotic cell death in human acute leukemia Jurkat T cells

    SciTech Connect

    Jun, Do Youn; Park, Hae Sun; Kim, Jun Seok; Kim, Jong Sik; Park, Wan; Song, Bang Ho; Kim, Hee-Sook; Taub, Dennis; Kim, Young Ho

    2008-09-15

    A pharmacological dose (2.5-10 {mu}M) of 17{alpha}-estradiol (17{alpha}-E{sub 2}) exerted a cytotoxic effect on human leukemias Jurkat T and U937 cells, which was not suppressed by the estrogen receptor (ER) antagonist ICI 182,780. Along with cytotoxicity in Jurkat T cells, several apoptotic events including mitochondrial cytochrome c release, activation of caspase-9, -3, and -8, PARP degradation, and DNA fragmentation were induced. The cytotoxicity of 17{alpha}-E{sub 2} was not blocked by the anti-Fas neutralizing antibody ZB-4. While undergoing apoptosis, there was a remarkable accumulation of G{sub 2}/M cells with the upregulatoin of cdc2 kinase activity, which was reflected in the Thr56 phosphorylation of Bcl-2. Dephosphorylation at Tyr15 and phosphorylation at Thr161 of cdc2, and significant increase in the cyclin B1 level were underlying factors for the cdc2 kinase activation. Whereas the 17{alpha}-E{sub 2}-induced apoptosis was completely abrogated by overexpression of Bcl-2 or by pretreatment with the pan-caspase inhibitor z-VAD-fmk, the accumulation of G{sub 2}/M cells significantly increased. The caspase-8 inhibitor z-IETD-fmk failed to influence 17{alpha}-E{sub 2}-mediated caspase-9 activation, but it markedly reduced caspase-3 activation and PARP degradation with the suppression of apoptosis, indicating the contribution of caspase-8; not as an upstream event of the mitochondrial cytochrome c release, but to caspase-3 activation. In the presence of hydroxyurea, which blocked the cell cycle progression at the G{sub 1}/S boundary, 17{alpha}-E{sub 2} failed to induce the G{sub 2}/M arrest as well as apoptosis. These results demonstrate that the cytotoxicity of 17{alpha}-E{sub 2} toward Jurkat T cells is attributable to apoptosis mainly induced in G{sub 2}/M-arrested cells, in an ER-independent manner, via a mitochondria-dependent caspase pathway regulated by Bcl-2.

  1. Possible intramuscular midazolam-associated cardiorespiratory arrest and death.

    PubMed

    Taylor, J W; Simon, K B

    1990-01-01

    Midazolam hydrochloride is commonly used for dental or endoscopic procedures. Although generally consisted safe when given intramuscularly, intravenous administration is known to cause respiratory and cardiovascular depression. This report describes the first published case of cardiorespiratory arrest and death associated with intramuscular administration of midazolam. Information regarding midazolam use is reviewed to provide recommendation for safe administration. PMID:2375138

  2. MLN2238, a proteasome inhibitor, induces caspase-dependent cell death, cell cycle arrest, and potentiates the cytotoxic activity of chemotherapy agents in rituximab-chemotherapy-sensitive or rituximab-chemotherapy-resistant B-cell lymphoma preclinical models.

    PubMed

    Gu, Juan J; Hernandez-Ilizaliturri, Francisco J; Mavis, Cory; Czuczman, Natalie M; Deeb, George; Gibbs, John; Skitzki, Joseph J; Patil, Ritesh; Czuczman, Myron S

    2013-11-01

    To further develop therapeutic strategies targeting the proteasome system, we studied the antitumor activity and mechanisms of action of MLN2238, a reversible proteasome inhibitor, in preclinical lymphoma models. Experiments were conducted in rituximab-chemotherapy-sensitive cell lines, rituximab-chemotherapy-resistant cell lines (RRCL), and primary B-cell lymphoma cells. Cells were exposed to MLN2238 or caspase-dependent inhibitors, and differences in cell viability, alterations in apoptotic protein levels, effects on cell cycle, and the possibility of synergy when combined with chemotherapeutic agents were evaluated. MLN2238 showed more potent dose-dependent and time-dependent cytotoxicity and inhibition of cell proliferation in lymphoma cells than bortezomib. Our data suggest that MLN2238 can induce caspase-independent cell death in RRCL. MLN2238 (and to a much lesser degree bortezomib) reduced RRCL S phase and induced cell cycle arrest in the G2/M phase. Exposure of rituximab-chemotherapy-sensitive cell lines and RRCL to MLN2238 potentiated the cytotoxic effects of gemcitabine, doxorubicin, and paclitaxel and overcame resistance to chemotherapy in RRCL. MLN2238 is a potent proteasome inhibitor active in rituximab-chemotherapy-sensitive and rituximab-chemotherapy-resistant cell models and potentiates the antitumor activity of chemotherapy agents and has the potential of becoming an effective therapeutic agent in the treatment of therapy-resistant B-cell lymphoma. PMID:23995855

  3. Cell cycle arrest is not yet senescence, which is not just cell cycle arrest: terminology for TOR-driven aging.

    PubMed

    Blagosklonny, Mikhail V

    2012-03-01

    Cell cycle arrest is not yet senescence. When the cell cycle is arrested, an inappropriate growth-promotion converts an arrest into senescence (geroconversion). By inhibiting the growth-promoting mTOR pathway, rapamycin decelerates geroconversion of the arrested cells. And as a striking example, while causing arrest, p53 may decelerate or suppress geroconversion (in some conditions). Here I discuss the meaning of geroconversion and also the terms gerogenes, gerossuppressors, gerosuppressants, gerogenic pathways, gero-promoters, hyperfunction and feedback resistance, regenerative potential, hypertrophy and secondary atrophy, pro-gerogenic and gerogenic cells. PMID:22394614

  4. Apoptosis in male germ cells in response to cyclin A1-deficiency and cell cycle arrest.

    PubMed

    Salazar, Glicella; Liu, Dong; Liao, Ching; Batkiewicz, Leah; Arbing, Rachel; Chung, Sanny S W; Lele, Karen; Wolgemuth, Debra J

    2003-10-15

    Male mice homozygous for a mutated allele of the cyclin A1 gene (Ccna1) are sterile due to a block in cell cycle progression before the first meiotic division. Meiosis arrest in Ccna1(-/-) spermatocytes is associated with desynapsis abnormalities, lowered MPF activity, and apoptosis as evidenced by TUNEL-positive staining. With time, adult testicular tubules exhibit severe degeneration: some tubules in the older animals are almost devoid of germ cells at various stages of spermatogenesis. The mechanisms by which the cells sense the cell cycle arrest and the regulation of the decision to undergo cell death are under investigation. PMID:14555236

  5. Cell Arrest and Cell Death in Mammalian Preimplantation Development: Lessons from the Bovine Model

    PubMed Central

    Leidenfrost, Sandra; Boelhauve, Marc; Reichenbach, Myriam; Güngör, Tuna; Reichenbach, Horst-Dieter; Sinowatz, Fred; Wolf, Eckhard; Habermann, Felix A.

    2011-01-01

    Background The causes, modes, biological role and prospective significance of cell death in preimplantation development in humans and other mammals are still poorly understood. Early bovine embryos represent a very attractive experimental model for the investigation of this fundamental and important issue. Methods and Findings To obtain reference data on the temporal and spatial occurrence of cell death in early bovine embryogenesis, three-dimensionally preserved embryos of different ages and stages of development up to hatched blastocysts were examined in toto by confocal laser scanning microscopy. In parallel, transcript abundance profiles for selected apoptosis-related genes were analyzed by real-time reverse transcriptase-polymerase chain reaction. Our study documents that in vitro as well as in vivo, the first four cleavage cycles are prone to a high failure rate including different types of permanent cell cycle arrest and subsequent non-apoptotic blastomere death. In vitro produced and in vivo derived blastocysts showed a significant incidence of cell death in the inner cell mass (ICM), but only in part with morphological features of apoptosis. Importantly, transcripts for CASP3, CASP9, CASP8 and FAS/FASLG were not detectable or found at very low abundances. Conclusions In vitro and in vivo, errors and failures of the first and the next three cleavage divisions frequently cause immediate embryo death or lead to aberrant subsequent development, and are the main source of developmental heterogeneity. A substantial occurrence of cell death in the ICM even in fast developing blastocysts strongly suggests a regular developmentally controlled elimination of cells, while the nature and mechanisms of ICM cell death are unclear. Morphological findings as well as transcript levels measured for important apoptosis-related genes are in conflict with the view that classical caspase-mediated apoptosis is the major cause of cell death in early bovine development. PMID

  6. DNA methylation is stable during replication and cell cycle arrest

    PubMed Central

    Vandiver, Amy R.; Idrizi, Adrian; Rizzardi, Lindsay; Feinberg, Andrew P.; Hansen, Kasper D.

    2015-01-01

    DNA methylation is an epigenetic modification with important functions in development. Large-scale loss of DNA methylation is a hallmark of cancer. Recent work has identified large genomic blocks of hypomethylation associated with cancer, EBV transformation and replicative senescence, all of which change the proportion of actively proliferating cells within the population measured. We asked if replication or cell-cycle arrest affects the global levels of methylation or leads to hypomethylated blocks as observed in other settings. We used fluorescence activated cell sorting to isolate primary dermal fibroblasts in G0, G1 and G2 based on DNA content and Ki67 staining. We additionally examined G0 cells arrested by contact inhibition for one week to determine the effects of extended arrest. We analyzed genome wide DNA methylation from sorted cells using whole genome bisulfite sequencing. This analysis demonstrated no global changes or large-scale hypomethylated blocks in any of the examined cell cycle phases, indicating that global levels of methylation are stable with replication and arrest. PMID:26648411

  7. Anticancer activity of taraxerol acetate in human glioblastoma cells and a mouse xenograft model via induction of autophagy and apoptotic cell death, cell cycle arrest and inhibition of cell migration

    PubMed Central

    HONG, JING-FANG; SONG, YING-FANG; LIU, ZHENG; ZHENG, ZHAO-CONG; CHEN, HONG-JIE; WANG, SHOU-SEN

    2016-01-01

    The aim of the present study was to investigate the in vitro and in vivo anticancer and apoptotic effects of taraxerol acetate in U87 human glioblastoma cells. The effects on cell cycle phase distribution, cell cycle-associated proteins, autophagy, DNA fragmentation and cell migration were assessed. Cell viability was determined using the MTT assay, and phase contrast and fluorescence microscopy was utilized to determine the viability and apoptotic morphological features of the U87 cells. Flow cytometry using propidium iodide and Annexin V-fluorescein isothiocyanate demonstrated the effect of taraxerol acetate on the cell cycle phase distribution and apoptosis induction. Western blot analysis was performed to investigate the effect of the taraxerol acetate on cell cycle-associated proteins and autophagy-linked LC3B-II proteins. The results demonstrated that taraxerol acetate induced dose- and time-dependent cytotoxic effects in the U87 cells. Apoptotic induction following taraxerol acetate treatment was observed and the percentage of apoptotic cells increased from 7.3% in the control cells, to 16.1, 44.1 and 76.7% in the 10, 50 and 150 µM taraxerol acetate-treated cells, respectively. Furthermore, taraxerol acetate treatment led to sub-G1 cell cycle arrest with a corresponding decrease in the number of S-phase cells. DNA fragments were observed as a result of the gel electrophoresis experiment following taraxerol acetate treatment. To investigate the inhibitory effects of taraxerol acetate on the migration of U87 cell, a wound healing assay was conducted. The number of cells that migrated to the scratched area decreased significantly following treatment with taraxerol acetate. In addition, taraxerol acetate inhibited tumor growth in a mouse xenograft model. Administration of 0.25 and 0.75 µg/g taraxerol acetate reduced the tumor weight from 1.2 g in the phosphate-buffered saline (PBS)-treated group (control) to 0.81 and 0.42 g, respectively. Similarly, 0.25 and 0

  8. Anticancer activity of taraxerol acetate in human glioblastoma cells and a mouse xenograft model via induction of autophagy and apoptotic cell death, cell cycle arrest and inhibition of cell migration.

    PubMed

    Hong, Jing-Fang; Song, Ying-Fang; Liu, Zheng; Zheng, Zhao-Cong; Chen, Hong-Jie; Wang, Shou-Sen

    2016-06-01

    The aim of the present study was to investigate the in vitro and in vivo anticancer and apoptotic effects of taraxerol acetate in U87 human glioblastoma cells. The effects on cell cycle phase distribution, cell cycle-associated proteins, autophagy, DNA fragmentation and cell migration were assessed. Cell viability was determined using the MTT assay, and phase contrast and fluorescence microscopy was utilized to determine the viability and apoptotic morphological features of the U87 cells. Flow cytometry using propidium iodide and Annexin V-fluorescein isothiocyanate demonstrated the effect of taraxerol acetate on the cell cycle phase distribution and apoptosis induction. Western blot analysis was performed to investigate the effect of the taraxerol acetate on cell cycle‑associated proteins and autophagy‑linked LC3B‑II proteins. The results demonstrated that taraxerol acetate induced dose‑ and time‑dependent cytotoxic effects in the U87 cells. Apoptotic induction following taraxerol acetate treatment was observed and the percentage of apoptotic cells increased from 7.3% in the control cells, to 16.1, 44.1 and 76.7% in the 10, 50 and 150 µM taraxerol acetate‑treated cells, respectively. Furthermore, taraxerol acetate treatment led to sub‑G1 cell cycle arrest with a corresponding decrease in the number of S‑phase cells. DNA fragments were observed as a result of the gel electrophoresis experiment following taraxerol acetate treatment. To investigate the inhibitory effects of taraxerol acetate on the migration of U87 cell, a wound healing assay was conducted. The number of cells that migrated to the scratched area decreased significantly following treatment with taraxerol acetate. In addition, taraxerol acetate inhibited tumor growth in a mouse xenograft model. Administration of 0.25 and 0.75 µg/g taraxerol acetate reduced the tumor weight from 1.2 g in the phosphate‑buffered saline (PBS)‑treated group (control) to 0.81 and 0.42

  9. Computation Molecular Kinetics Model of HZE Induced Cell Cycle Arrest

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Ren, Lei

    2004-01-01

    Cell culture models play an important role in understanding the biological effectiveness of space radiation. High energy and charge (HZE) ions produce prolonged cell cycle arrests at the G1/S and G2/M transition points in the cell cycle. A detailed description of these phenomena is needed to integrate knowledge of the expression of DNA damage in surviving cells, including the determination of relative effectiveness factors between different types of radiation that produce differential types of DNA damage and arrest durations. We have developed a hierarchical kinetics model that tracks the distribution of cells in various cell phase compartments (early G1, late G1, S, G2, and M), however with transition rates that are controlled by rate-limiting steps in the kinetics of cyclin-cdk's interactions with their families of transcription factors and inhibitor molecules. The coupling of damaged DNA molecules to the downstream cyclin-cdk inhibitors is achieved through a description of the DNA-PK and ATM signaling pathways. For HZE irradiations we describe preliminary results, which introduce simulation of the stochastic nature of the number of direct particle traversals per cell in the modulation of cyclin-cdk and cell cycle population kinetics. Comparison of the model to data for fibroblast cells irradiated photons or HZE ions are described.

  10. Ethanol Mediates Cell Cycle Arrest and Apoptosis in SK-N-SH Neuroblastoma Cells

    PubMed Central

    Lee, Maria; Song, Byoung-Joon; Kwon, Yongil

    2014-01-01

    Background: The mechanisms of cell or organ damage by chronic alcohol consumption are still poorly understood. The present study aimed to investigate the role of the mitogen-activated protein kinases during ethanol-induced damage to SK-N-SH neuroblastoma cells. Methods: Cells were treated with ethanol and subsequently analyzed for cell morphology, viability, and DNA fragmentation. Immunoblot analysis was performed to assess various proteins levels associated with cell cycle arrest and apoptosis after ethanol exposure. Results: Ethanol induced time- and dose-dependent cell death in SK-N-SH cells and increased c-Jun N-terminal protein kinase (JNK) activity in a time- and concentration dependent manner. In contrast, p38 kinase activity increased transiently. After treatment with JNK or p38 kinase inhibitors, ethanol-induced cell death significantly reduced. Ethanol-induced cell death was accompanied by increased cytochrome c release and caspase 3 activity observed at 12 h. In contrast, the level of anti-apoptotic Bcl-2 protein did not change. Ethanol also increased the phosphorylation of p53 and p53 activation was followed by an increase in the p21 tumor suppressor protein accompanied by a gradual decrease in phospho-Rb protein. Conclusion: Our results suggest that ethanol mediates apoptosis of neuroblastoma cells by stimulating p53-related cell cycle arrest mediated through activation of the JNK-related pathway. PMID:25337571

  11. Pneumococcal Pneumolysin Induces DNA Damage and Cell Cycle Arrest.

    PubMed

    Rai, Prashant; He, Fang; Kwang, Jimmy; Engelward, Bevin P; Chow, Vincent T K

    2016-01-01

    Streptococcus pneumoniae produces pneumolysin toxin as a key virulence factor against host cells. Pneumolysin is a cholesterol-dependent cytolysin (CDC) toxin that forms lytic pores in host membranes and mediates pneumococcal disease pathogenesis by modulating inflammatory responses. Here, we show that pneumolysin, which is released during bacterial lysis, induces DNA double strand breaks (DSBs), as indicated by ataxia telangiectasia mutated (ATM)-mediated H2AX phosphorylation (γH2AX). Pneumolysin-induced γH2AX foci recruit mediator of DNA damage checkpoint 1 (MDC1) and p53 binding protein 1 (53BP1), to sites of DSBs. Importantly, results show that toxin-induced DNA damage precedes cell cycle arrest and causes apoptosis when DNA-dependent protein kinase (DNA-PK)-mediated non-homologous end joining is inhibited. Further, we observe that cells that were undergoing DNA replication harbored DSBs in greater frequency during pneumolysin treatment. This observation raises the possibility that DSBs might be arising as a result of replication fork breakdown. Additionally, neutralizing the oligomerization domain of pneumolysin with monoclonal antibody suppresses DNA damage and also cell cycle arrest, indicating that pneumolysin oligomerization is important for causing DNA damage. Taken together, this study reveals a previously unidentified ability of pneumolysin to induce cytotoxicity via DNA damage, with implications in the pathophysiology of S. pneumoniae infection. PMID:27026501

  12. Pneumococcal Pneumolysin Induces DNA Damage and Cell Cycle Arrest

    PubMed Central

    Rai, Prashant; He, Fang; Kwang, Jimmy; Engelward, Bevin P.; Chow, Vincent T.K.

    2016-01-01

    Streptococcus pneumoniae produces pneumolysin toxin as a key virulence factor against host cells. Pneumolysin is a cholesterol-dependent cytolysin (CDC) toxin that forms lytic pores in host membranes and mediates pneumococcal disease pathogenesis by modulating inflammatory responses. Here, we show that pneumolysin, which is released during bacterial lysis, induces DNA double strand breaks (DSBs), as indicated by ataxia telangiectasia mutated (ATM)-mediated H2AX phosphorylation (γH2AX). Pneumolysin-induced γH2AX foci recruit mediator of DNA damage checkpoint 1 (MDC1) and p53 binding protein 1 (53BP1), to sites of DSBs. Importantly, results show that toxin-induced DNA damage precedes cell cycle arrest and causes apoptosis when DNA-dependent protein kinase (DNA-PK)-mediated non-homologous end joining is inhibited. Further, we observe that cells that were undergoing DNA replication harbored DSBs in greater frequency during pneumolysin treatment. This observation raises the possibility that DSBs might be arising as a result of replication fork breakdown. Additionally, neutralizing the oligomerization domain of pneumolysin with monoclonal antibody suppresses DNA damage and also cell cycle arrest, indicating that pneumolysin oligomerization is important for causing DNA damage. Taken together, this study reveals a previously unidentified ability of pneumolysin to induce cytotoxicity via DNA damage, with implications in the pathophysiology of S. pneumoniae infection. PMID:27026501

  13. Piperlongumine Suppresses Proliferation of Human Oral Squamous Cell Carcinoma through Cell Cycle Arrest, Apoptosis and Senescence.

    PubMed

    Chen, San-Yuan; Liu, Geng-Hung; Chao, Wen-Ying; Shi, Chung-Sheng; Lin, Ching-Yen; Lim, Yun-Ping; Lu, Chieh-Hsiang; Lai, Peng-Yeh; Chen, Hau-Ren; Lee, Ying-Ray

    2016-01-01

    Oral squamous cell carcinoma (OSCC), an aggressive cancer originating in the oral cavity, is one of the leading causes of cancer deaths in males worldwide. This study investigated the antitumor activity and mechanisms of piperlongumine (PL), a natural compound isolated from Piper longum L., in human OSCC cells. The effects of PL on cell proliferation, the cell cycle, apoptosis, senescence and reactive oxygen species (ROS) levels in human OSCC cells were investigated. PL effectively inhibited cell growth, caused cell cycle arrest and induced apoptosis and senescence in OSCC cells. Moreover, PL-mediated anti-human OSCC behavior was inhibited by an ROS scavenger N-acetyl-l-cysteine (NAC) treatment, suggesting that regulation of ROS was involved in the mechanism of the anticancer activity of PL. These findings suggest that PL suppresses tumor growth by regulating the cell cycle and inducing apoptosis and senescence and is a potential chemotherapy agent for human OSCC cells. PMID:27120594

  14. Piperlongumine Suppresses Proliferation of Human Oral Squamous Cell Carcinoma through Cell Cycle Arrest, Apoptosis and Senescence

    PubMed Central

    Chen, San-Yuan; Liu, Geng-Hung; Chao, Wen-Ying; Shi, Chung-Sheng; Lin, Ching-Yen; Lim, Yun-Ping; Lu, Chieh-Hsiang; Lai, Peng-Yeh; Chen, Hau-Ren; Lee, Ying-Ray

    2016-01-01

    Oral squamous cell carcinoma (OSCC), an aggressive cancer originating in the oral cavity, is one of the leading causes of cancer deaths in males worldwide. This study investigated the antitumor activity and mechanisms of piperlongumine (PL), a natural compound isolated from Piper longum L., in human OSCC cells. The effects of PL on cell proliferation, the cell cycle, apoptosis, senescence and reactive oxygen species (ROS) levels in human OSCC cells were investigated. PL effectively inhibited cell growth, caused cell cycle arrest and induced apoptosis and senescence in OSCC cells. Moreover, PL-mediated anti-human OSCC behavior was inhibited by an ROS scavenger N-acetyl-l-cysteine (NAC) treatment, suggesting that regulation of ROS was involved in the mechanism of the anticancer activity of PL. These findings suggest that PL suppresses tumor growth by regulating the cell cycle and inducing apoptosis and senescence and is a potential chemotherapy agent for human OSCC cells. PMID:27120594

  15. Radioprotection and Cell Cycle Arrest of Intestinal Epithelial Cells by Darinaparsin, a Tumor Radiosensitizer

    SciTech Connect

    Tian, Junqiang; Doi, Hiroshi; Saar, Matthias; Santos, Jennifer; Li, Xuejun; Peehl, Donna M.; Knox, Susan J.

    2013-12-01

    Purpose: It was recently reported that the organic arsenic compound darinaparsin (DPS) is a cytotoxin and radiosensitizer of tumor cells in vitro and in subcutaneous xenograft tumors. Surprisingly, it was also found that DPS protects normal intestinal crypt epithelial cells (CECs) from clonogenic death after ionizing radiation (IR). Here we tested the DPS radiosensitizing effect in a clinically relevant model of prostate cancer and explored the radioprotective effect and mechanism of DPS on CECs. Methods and Materials: The radiation modification effect of DPS was tested in a mouse model of orthotopic xenograft prostate cancer and of IR-induced acute gastrointestinal syndrome. The effect of DPS on CEC DNA damage and DNA damage responses was determined by immunohistochemistry. Results: In the mouse model of IR-induced gastrointestinal syndrome, DPS treatment before IR accelerated recovery from body weight loss and increased animal survival. DPS decreased post-IR DNA damage and cell death, suggesting that the radioprotective effect was mediated by enhanced DNA damage repair. Shortly after DPS injection, significant cell cycle arrest was observed in CECs at both G1/S and G2/M checkpoints, which was accompanied by the activation of cell cycle inhibitors p21 and growth arrest and DNA-damage-inducible protein 45 alpha (GADD45A). Further investigation revealed that DPS activated ataxia telangiectasia mutated (ATM), an important inducer of DNA damage repair and cell cycle arrest. Conclusions: DPS selectively radioprotected normal intestinal CECs and sensitized prostate cancer cells in a clinically relevant model. This effect may be, at least in part, mediated by DNA damage response activation and has the potential to significantly increase the therapeutic index of radiation therapy.

  16. Tangeretin induces cell cycle arrest and apoptosis through upregulation of PTEN expression in glioma cells.

    PubMed

    Ma, Li-Li; Wang, Da-Wei; Yu, Xu-Dong; Zhou, Yan-Ling

    2016-07-01

    Tangeretin (TANG), present in peel of citrus fruits, has been shown to various medicinal properties such as chemopreventive and neuroprotective. However, the chemopreventive effect of TANG on glioblastoma cells has not been examined. The present study was designed to explore the anticancer potential of TANG in glioblastoma cells and to investigate the related mechanism. Human glioblastoma U-87MG and LN-18 cells were treated with 45μM concentration of TANG and cell growth was measured by MTT assay. The cell cycle distribution and cell death were measured by flow cytometry. The expression of cell cycle and apoptosis related genes were analyzed by quantitative RT-PCR and western blot. The cells treated with TANG were significantly increased cell growth suppression and cell death effects than vehicle treated cells. Further, TANG treatment increases G2/M arrest and apoptosis by modulating PTEN and cell-cycle regulated genes such as cyclin-D and cdc-2 mRNA and protein expressions. Moreover, the ability of TANG to decrease cell growth and to induce cell death was compromised when PTEN was knockdown by siRNA. Taken together, the chemopreventive effect of TANG is associated with regulation of cell-cycle and apoptosis in glioblastoma, thereby attenuating glioblastoma cell growth. Hence, the present findings suggest that TANG may be a therapeutic agent for glioblastoma treatment. PMID:27261630

  17. Overexpression of TDP-43 causes partially p53-dependent G2/M arrest and p53-independent cell death in HeLa cells.

    PubMed

    Lee, Kikyo; Suzuki, Hiroaki; Aiso, Sadakazu; Matsuoka, Masaaki

    2012-01-11

    It has been hypothesized that the dysregulation of transactive response DNA-binding protein-43 (TDP-43) in neurons is closely linked to the pathogenesis of amyotrophic lateral sclerosis and frontotemporal lobar degeneration with ubiquitinated inclusions. However, it remains undefined whether the dysregulation of TDP-43 in non-neuronal cells, such as glial cells, contributes to the pathogenesis of these neurodegenerative diseases. Primarily using HeLa cells, we show that a low-grade overexpression of TDP-43, 2- to 5-fold greater than endogenous expression, which is thought to mimic the gain of function of TDP-43, induced cell cycle arrest at the G2/M phase and cell death in cultured non-neuronal cells. Since the activation of p53 may induce G2/M arrest and/or cell death in many abnormal situations, we examined the mechanism underlying G2/M arrest from the standpoint of p53 regulation. It was determined that the TDP-43-induced G2/M arrest was attenuated, while TDP-43-induced death was not attenuated, in cells in which the p53 function was compromised. These data collectively indicate that TDP-43 causes G2/M arrest in a partially p53-dependent manner and it causes cell death in a p53-independent manner in cycling cells. Because it is likely that the impaired proliferation in glial cells causes a decrease in the neuron-supporting ability, these findings further suggests that the gain of function of TDP-43 may cause neurotoxicity by inducing cell cycle arrest and death in glial cells. PMID:22133803

  18. α-Mangostin Induces Apoptosis and Cell Cycle Arrest in Oral Squamous Cell Carcinoma Cell

    PubMed Central

    Kwak, Hyun-Ho; Park, Bong-Soo

    2016-01-01

    Mangosteen has long been used as a traditional medicine and is known to have antibacterial, antioxidant, and anticancer effects. Although the effects of α-mangostin, a natural compound extracted from the pericarp of mangosteen, have been investigated in many studies, there is limited data on the effects of the compound in human oral squamous cell carcinoma (OSCC). In this study, α-mangostin was assessed as a potential anticancer agent against human OSCC cells. α-Mangostin inhibited cell proliferation and induced cell death in OSCC cells in a dose- and time-dependent manner with little to no effect on normal human PDLF cells. α-Mangostin treatment clearly showed apoptotic evidences such as nuclear fragmentation and accumulation of annexin V and PI-positive cells on OSCC cells. α-Mangostin treatment also caused the collapse of mitochondrial membrane potential and the translocation of cytochrome c from the mitochondria into the cytosol. The expressions of the mitochondria-related proteins were activated by α-mangostin. Treatment with α-mangostin also induced G1 phase arrest and downregulated cell cycle-related proteins (CDK/cyclin). Hence, α-mangostin specifically induces cell death and inhibits proliferation in OSCC cells via the intrinsic apoptosis pathway and cell cycle arrest at the G1 phase, suggesting that α-mangostin may be an effective agent for the treatment of OSCC. PMID:27478478

  19. High-dose irradiation induces cell cycle arrest, apoptosis, and developmental defects during Drosophila oogenesis.

    PubMed

    Shim, Hee Jin; Lee, Eun-Mi; Nguyen, Long Duy; Shim, Jaekyung; Song, Young-Han

    2014-01-01

    Ionizing radiation (IR) treatment induces a DNA damage response, including cell cycle arrest, DNA repair, and apoptosis in metazoan somatic cells. Because little has been reported in germline cells, we performed a temporal analysis of the DNA damage response utilizing Drosophila oogenesis as a model system. Oogenesis in the adult Drosophila female begins with the generation of 16-cell cyst by four mitotic divisions of a cystoblast derived from the germline stem cells. We found that high-dose irradiation induced S and G2 arrests in these mitotically dividing germline cells in a grp/Chk1- and mnk/Chk2-dependent manner. However, the upstream kinase mei-41, Drosophila ATR ortholog, was required for the S-phase checkpoint but not for the G2 arrest. As in somatic cells, mnk/Chk2 and dp53 were required for the major cell death observed in early oogenesis when oocyte selection and meiotic recombination occurs. Similar to the unscheduled DNA double-strand breaks (DSBs) generated from defective repair during meiotic recombination, IR-induced DSBs produced developmental defects affecting the spherical morphology of meiotic chromosomes and dorsal-ventral patterning. Moreover, various morphological abnormalities in the ovary were detected after irradiation. Most of the IR-induced defects observed in oogenesis were reversible and were restored between 24 and 96 h after irradiation. These defects in oogenesis severely reduced daily egg production and the hatch rate of the embryos of irradiated female. In summary, irradiated germline cells induced DSBs, cell cycle arrest, apoptosis, and developmental defects resulting in reduction of egg production and defective embryogenesis. PMID:24551207

  20. Programmed cell cycle arrest is required for infection of corn plants by the fungus Ustilago maydis.

    PubMed

    Castanheira, Sónia; Mielnichuk, Natalia; Pérez-Martín, José

    2014-12-01

    Ustilago maydis is a plant pathogen that requires a specific structure called infective filament to penetrate the plant tissue. Although able to grow, this filament is cell cycle arrested on the plant surface. This cell cycle arrest is released once the filament penetrates the plant tissue. The reasons and mechanisms for this cell cycle arrest are unknown. Here, we have tried to address these questions. We reached three conclusions from our studies. First, the observed cell cycle arrest is the result of the cooperation of at least two distinct mechanisms: one involving the activation of the DNA damage response (DDR) cascade; and the other relying on the transcriptional downregulation of Hsl1, a kinase that modulates the G2/M transition. Second, a sustained cell cycle arrest during the infective filament step is necessary for the virulence in U. maydis, as a strain unable to arrest the cell cycle was severely impaired in its ability to infect corn plants. Third, production of the appressorium, a structure required for plant penetration, is incompatible with an active cell cycle. The inability to infect plants by strains defective in cell cycle arrest seems to be caused by their failure to induce the appressorium formation process. In summary, our findings uncover genetic circuits to arrest the cell cycle during the growth of this fungus on the plant surface, thus allowing the penetration into plant tissue. PMID:25411209

  1. How Trypanosoma cruzi handles cell cycle arrest promoted by camptothecin, a topoisomerase I inhibitor.

    PubMed

    Zuma, Aline Araujo; Mendes, Isabela Cecília; Reignault, Lissa Catherine; Elias, Maria Carolina; de Souza, Wanderley; Machado, Carlos Renato; Motta, Maria Cristina M

    2014-02-01

    The protozoan Trypanosoma cruzi is the etiological agent of Chagas disease, which affects approximately 8 million people in Latin America. This parasite contains a single nucleus and a kinetoplast, which harbors the mitochondrial DNA (kDNA). DNA topoisomerases act during replication, transcription and repair and modulate DNA topology by reverting supercoiling in the DNA double-strand. In this work, we evaluated the effects promoted by camptothecin, a topoisomerase I inhibitor that promotes protozoan proliferation impairment, cell cycle arrest, ultrastructure alterations and DNA lesions in epimastigotes of T. cruzi. The results showed that inhibition of cell proliferation was reversible only at the lowest drug concentration (1μM) used. The unpacking of nuclear heterochromatin and mitochondrion swelling were the main ultrastructural modifications observed. Inhibition of parasite proliferation also led to cell cycle arrest, which was most likely caused by nuclear DNA lesions. Following camptothecin treatment, some of the cells restored their DNA, whereas others entered early apoptosis but did not progress to late apoptosis, indicating that the protozoa stay alive in a "senescence-like" state. This programmed cell death may be associated with a decrease in mitochondrial membrane potential and an increase in the production of reactive oxygen species. Taken together, these results indicate that the inhibition of T. cruzi proliferation is related to events capable of affecting cell cycle, DNA organization and mitochondrial activity. PMID:24530483

  2. Induction of apoptosis and cell cycle arrest in human colorectal carcinoma by Litchi seed extract.

    PubMed

    Hsu, Chih-Ping; Lin, Chih-Cheng; Huang, Chiu-Chen; Lin, Yi-Hsien; Chou, Jyh-Ching; Tsia, Yu-Ting; Su, Jhih-Rou; Chung, Yuan-Chiang

    2012-01-01

    The Litchi (Litchi chinensis) fruit products possess rich amounts of flavanoids and proanthocyanidins. Its pericarp has been shown to inhibit breast and liver cancer cell growth. However, the anticolorectal cancer effect of Litchi seed extract has not yet been reported. In this study, the effects of polyphenol-rich Litchi seed ethanol extract (LCSP) on the proliferation, cell cycle, and apoptosis of two colorectal cancer cell lines Colo320DM and SW480 were examined. The results demonstrated that LCSP significantly induced apoptotic cell death in a dose-dependent manner and arrested cell cycle in G2/M in colorectal carcinoma cells. LCSP also suppressed cyclins and elevated the Bax : Bcl-2 ratio and caspase 3 activity. This study provides in vitro evidence that LCSP serves as a potential chemopreventive agent for colorectal cancer. PMID:23093841

  3. Fusarochromanone Induces G1 Cell Cycle Arrest and Apoptosis in COS7 and HEK293 Cells

    PubMed Central

    Gu, Ying; Chen, Xin; Shang, Chaowei; Singh, Karnika; Barzegar, Mansoureh; Mahdavian, Elahe; Salvatore, Brian A.; Jiang, Shanxiang; Huang, Shile

    2014-01-01

    Fusarochromanone (FC101), a mycotoxin produced by the fungus Fusarium equiseti, is frequently observed in the contaminated grains and feedstuffs, which is toxic to animals and humans. However, the underlying molecular mechanism remains to be defined. In this study, we found that FC101 inhibited cell proliferation and induced cell death in COS7 and HEK293 cells in a concentration-dependent manner. Flow cytometric analysis showed that FC101 induced G1 cell cycle arrest and apoptosis in the cells. Concurrently, FC101 downregulated protein expression of cyclin D1, cyclin-dependent kinases (CDK4 and CDK6), and Cdc25A, and upregulated expression of the CDK inhibitors (p21Cip1 and p27Kip1), resulting in hypophosphorylation of Rb. FC101 also inhibited protein expression of Bcl-2, Bcl-xL, Mcl-1 and survivin, and induced expression of BAD, leading to activation of caspase 3 and cleavage of PARP, indicating caspase-dependent apoptosis. However, Z-VAD-FMK, a pan-caspase inhibitor, only partially prevented FC101-induced cell death, implying that FC101 may induce cell death through both caspase-dependent and -independent mechanisms. Our results support the notion that FC101 executes its toxicity at least by inhibiting cell proliferation and inducing cell death. PMID:25384025

  4. Bcl-xL controls a switch between cell death modes during mitotic arrest

    PubMed Central

    Bah, N; Maillet, L; Ryan, J; Dubreil, S; Gautier, F; Letai, A; Juin, P; Barillé-Nion, S

    2014-01-01

    Antimitotic agents such as microtubule inhibitors (paclitaxel) are widely used in cancer therapy while new agents blocking mitosis onset are currently in development. All these agents impose a prolonged mitotic arrest in cancer cells that relies on sustained activation of the spindle assembly checkpoint and may lead to subsequent cell death by incompletely understood molecular events. We have investigated the role played by anti-apoptotic Bcl-2 family members in the fate of mitotically arrested mammary tumor cells treated with paclitaxel, or depleted in Cdc20, the activator of the anaphase promoting complex. Under these conditions, a weak and delayed mitotic cell death occurs that is caspase- and Bax/Bak-independent. Moreover, BH3 profiling assays indicate that viable cells during mitotic arrest are primed to die by apoptosis and that Bcl-xL is required to maintain mitochondrial integrity. Consistently, Bcl-xL depletion, or treatment with its inhibitor ABT-737 (but not with the specific Bcl-2 inhibitor ABT-199), during mitotic arrest converts cell response to antimitotics to efficient caspase and Bax-dependent apoptosis. Apoptotic priming under conditions of mitotic arrest relies, at least in part, on the phosphorylation on serine 62 of Bcl-xL, which modulates its interaction with Bax and its sensitivity to ABT-737. The phospho-mimetic S62D-Bcl-xL mutant is indeed less efficient than the corresponding phospho-deficient S62A-Bcl-xL mutant in sequestrating Bax and in protecting cancer cells from mitotic cell death or yeast cells from Bax-induced growth inhibition. Our results provide a rationale for combining Bcl-xL targeting to antimitotic agents to improve clinical efficacy of antimitotic strategy in cancer therapy. PMID:24922075

  5. DNA Damage, Cell Cycle Arrest, and Apoptosis Induction Caused by Lead in Human Leukemia Cells

    PubMed Central

    Yedjou, Clement G.; Tchounwou, Hervey M.; Tchounwou, Paul B.

    2015-01-01

    In recent years, the industrial use of lead has been significantly reduced from paints and ceramic products, caulking, and pipe solder. Despite this progress, lead exposure continues to be a significant public health concern. The main goal of this research was to determine the in vitro mechanisms of lead nitrate [Pb(NO3)2] to induce DNA damage, apoptosis, and cell cycle arrest in human leukemia (HL-60) cells. To reach our goal, HL-60 cells were treated with different concentrations of Pb(NO3)2 for 24 h. Live cells and necrotic death cells were measured by the propidium idiode (PI) assay using the cellometer vision. Cell apoptosis was measured by the flow cytometry and DNA laddering. Cell cycle analysis was evaluated by the flow cytometry. The result of the PI demonstrated a significant (p < 0.05) increase of necrotic cell death in Pb(NO3)2-treated cells, indicative of membrane rupture by Pb(NO3)2 compared to the control. Data generated from the comet assay indicated a concentration-dependent increase in DNA damage, showing a significant increase (p < 0.05) in comet tail-length and percentages of DNA cleavage. Data generated from the flow cytometry assessment indicated that Pb(NO3)2 exposure significantly (p < 0.05) increased the proportion of caspase-3 positive cells (apoptotic cells) compared to the control. The flow cytometry assessment also indicated Pb(NO3)2 exposure caused cell cycle arrest at the G0/G1 checkpoint. The result of DNA laddering assay showed presence of DNA smear in the agarose gel with little presence of DNA fragments in the treated cells compared to the control. In summary, Pb(NO3)2 inhibits HL-60 cells proliferation by not only inducing DNA damage and cell cycle arrest at the G0/G1 checkpoint but also triggering the apoptosis through caspase-3 activation and nucleosomal DNA fragmentation accompanied by secondary necrosis. We believe that our study provides a new insight into the mechanisms of Pb(NO3)2 exposure and its associated adverse health

  6. DNA Damage, Cell Cycle Arrest, and Apoptosis Induction Caused by Lead in Human Leukemia Cells.

    PubMed

    Yedjou, Clement G; Tchounwou, Hervey M; Tchounwou, Paul B

    2016-01-01

    In recent years, the industrial use of lead has been significantly reduced from paints and ceramic products, caulking, and pipe solder. Despite this progress, lead exposure continues to be a significant public health concern. The main goal of this research was to determine the in vitro mechanisms of lead nitrate [Pb(NO₃)₂] to induce DNA damage, apoptosis, and cell cycle arrest in human leukemia (HL-60) cells. To reach our goal, HL-60 cells were treated with different concentrations of Pb(NO₃)₂ for 24 h. Live cells and necrotic death cells were measured by the propidium idiode (PI) assay using the cellometer vision. Cell apoptosis was measured by the flow cytometry and DNA laddering. Cell cycle analysis was evaluated by the flow cytometry. The result of the PI demonstrated a significant (p < 0.05) increase of necrotic cell death in Pb(NO₃)₂-treated cells, indicative of membrane rupture by Pb(NO₃)₂ compared to the control. Data generated from the comet assay indicated a concentration-dependent increase in DNA damage, showing a significant increase (p < 0.05) in comet tail-length and percentages of DNA cleavage. Data generated from the flow cytometry assessment indicated that Pb(NO₃)₂ exposure significantly (p < 0.05) increased the proportion of caspase-3 positive cells (apoptotic cells) compared to the control. The flow cytometry assessment also indicated Pb(NO₃)₂ exposure caused cell cycle arrest at the G₀/G₁ checkpoint. The result of DNA laddering assay showed presence of DNA smear in the agarose gel with little presence of DNA fragments in the treated cells compared to the control. In summary, Pb(NO₃)₂ inhibits HL-60 cells proliferation by not only inducing DNA damage and cell cycle arrest at the G₀/G₁ checkpoint but also triggering the apoptosis through caspase-3 activation and nucleosomal DNA fragmentation accompanied by secondary necrosis. We believe that our study provides a new insight into the mechanisms of Pb

  7. Apoptosis and cell-cycle arrest in human and murine tumor cells are initiated by isoprenoids.

    PubMed

    Mo, H; Elson, C E

    1999-04-01

    Diverse classes of phytochemicals initiate biological responses that effectively lower cancer risk. One class of phytochemicals, broadly defined as pure and mixed isoprenoids, encompasses an estimated 22,000 individual components. A representative mixed isoprenoid, gamma-tocotrienol, suppresses the growth of murine B16(F10) melanoma cells, and with greater potency, the growth of human breast adenocarcinoma (MCF-7) and human leukemic (HL-60) cells. beta-Ionone, a pure isoprenoid, suppresses the growth of B16 cells and with greater potency, the growth of MCF-7, HL-60 and human colon adenocarcinoma (Caco-2) cells. Results obtained with diverse cell lines differing in ras and p53 status showed that the isoprenoid-mediated suppression of growth is independent of mutated ras and p53 functions. beta-Ionone suppressed the growth of human colon fibroblasts (CCD-18Co) but only when present at three-fold the concentration required to suppress the growth of Caco-2 cells. The isoprenoids initiated apoptosis and, concomitantly arrested cells in the G1 phase of the cell cycle. Both suppress 3-hydroxy-3-methylglutaryl CoA reductase activity. beta-Ionone and lovastatin interfered with the posttranslational processing of lamin B, an activity essential to assembly of daughter nuclei. This interference, we postulate, renders neosynthesized DNA available to the endonuclease activities leading to apoptotic cell death. Lovastatin-imposed mevalonate starvation suppressed the glycosylation and translocation of growth factor receptors to the cell surface. As a consequence, cells were arrested in the G1 phase of the cell cycle. This rationale may apply to the isoprenoid-mediated G1-phase arrest of tumor cells. The additive and potentially synergistic actions of these isoprenoids in the suppression of tumor cell proliferation and initiation of apoptosis coupled with the mass action of the diverse isoprenoid constituents of plant products may explain, in part, the impact of fruit, vegetable

  8. Direct inhibition of Retinoblastoma phosphorylation by Nimbolide causes cell cycle arrest and suppresses glioblastoma growth

    PubMed Central

    Anderson, Jane; Liu, Xiaona; Henry, Heather; Gasilina, Anjelika; Nassar, Nicholas; Ghosh, Jayeeta; Clark, Jason P; Kumar, Ashish; Pauletti, Giovanni M.; Ghosh, Pradip K; Dasgupta, Biplab

    2013-01-01

    Purpose Classical pharmacology allows the use and development of conventional phytomedicine faster and more economically than conventional drugs. This approach should be tested for their efficacy in terms of complementarity and disease control. The purpose of this study was to determine the molecular mechanisms by which nimbolide, a triterpenoid found in the well-known medicinal plant Azadirachta indica controls glioblastoma (GBM) growth. Experimental Design Using in vitro signaling, anchorage-independent growth, kinase assays, and xenograft models, we investigated the mechanisms of its growth inhibition in glioblastoma. Results We show that nimbolide or an ethanol soluble fraction of A. indica leaves (Azt) that contains nimbolide as the principal cytotoxic agent is highly cytotoxic against GBM in vitro and in vivo. Azt caused cell cycle arrest, most prominently at the G1-S stage in GBM cells expressing EGFRvIII, an oncogene present in about 20-25% of GBMs. Azt/nimbolide directly inhibited CDK4/CDK6 kinase activity leading to hypophosphorylation of the retinoblastoma (RB) protein, cell cycle arrest at G1-S and cell death. Independent of RB hypophosphorylation, Azt also significantly reduced proliferative and survival advantage of GBM cells in vitro and in tumor xenografts by downregulating Bcl2 and blocking growth factor induced phosphorylation of Akt, Erk1/2 and STAT3. These effects were specific since Azt did not affect mTOR or other cell cycle regulators. In vivo, Azt completely prevented initiation and inhibited progression of GBM growth. Conclusions Our preclinical findings demonstrate Nimbolide as a potent anti-glioma agent that blocks cell cycle and inhibits glioma growth in vitro and in vivo. PMID:24170547

  9. Carrageenan Induces Cell Cycle Arrest in Human Intestinal Epithelial Cells in Vitro1–3

    PubMed Central

    Bhattacharyya, Sumit; Borthakur, Alip; Dudeja, Pradeep K.; Tobacman, Joanne K.

    2016-01-01

    Multiple studies in animal models have shown that the commonly used food additive carrageenan (CGN) induces inflammation and intestinal neoplasia. We performed the first studies to determine the effects of CGN exposure on human intestinal epithelial cells (IEC) in tissue culture and tested the effect of very low concentrations (1–10 mg/L) of undegraded, high-molecular weight CGN. These concentrations of CGN are less than the anticipated exposure of the human colon to CGN from the average Western diet. In the human colonic epithelial cell line NCM460 and in primary human colonic epithelial cells that were exposed to CGN for 1–8 d, we found increased cell death, reduced cell proliferation, and cell cycle arrest compared with unexposed control cells. After 6–8 d of CGN exposure, the percentage of cells reentering G0–G1 significantly decreased and the percentages of cells in S and G2-M phases significantly increased. Increases in activated p53, p21, and p15 followed CGN exposure, consistent with CGN-induced cell cycle arrest. Additional data, including DNA ladder, poly ADP ribose polymerase Western blot, nuclear DNA staining, and activities of caspases 3 and 7, indicated no evidence of increased apoptosis following CGN exposure and were consistent with CGN-induced necrotic cell death. These data document for the first time, to our knowledge, marked adverse effects of low concentrations of CGN on survival of normal human IEC and suggest that CGN exposure may have a role in development of human intestinal pathology. PMID:18287351

  10. Effects of ZnO nanoparticles in plants: Cytotoxicity, genotoxicity, deregulation of antioxidant defenses, and cell-cycle arrest.

    PubMed

    Ghosh, Manosij; Jana, Aditi; Sinha, Sonali; Jothiramajayam, Manivannan; Nag, Anish; Chakraborty, Anirban; Mukherjee, Amitava; Mukherjee, Anita

    2016-09-01

    Cytotoxicity, genotoxicity, and biochemical effects were evaluated in the plants Allium cepa, Nicotiana tabacum, and Vicia faba following exposure to ZnO nanoparticles (np; diameter, ∼85nm). In the root meristems of Allium cepa cells, we observed loss of membrane integrity, increased chromosome aberrations, micronucleus formation, DNA strand breaks, and cell-cycle arrest at the G2/M checkpoint. In Vicia faba and Nicotiana tabacum, we observed increased intracellular ROS production, lipid peroxidation, and activities of some antioxidant enzymes. TEM images revealed gross morphological alterations and internalization of the np. Our findings provide evidence of ZnO np toxicity, characterized by deregulation of components of ROS-antioxidant machinery, leading to DNA damage, cell-cycle arrest, and cell death. These plants, especially Allium cepa, are reliable systems for assessment of np toxicology. PMID:27542712

  11. Danusertib, a potent pan-Aurora kinase and ABL kinase inhibitor, induces cell cycle arrest and programmed cell death and inhibits epithelial to mesenchymal transition involving the PI3K/Akt/mTOR-mediated signaling pathway in human gastric cancer AGS and NCI-N78 cells

    PubMed Central

    Yuan, Chun-Xiu; Zhou, Zhi-Wei; Yang, Yin-Xue; He, Zhi-Xu; Zhang, Xueji; Wang, Dong; Yang, Tianxing; Pan, Si-Yuan; Chen, Xiao-Wu; Zhou, Shu-Feng

    2015-01-01

    Gastric cancer is the second leading cause of cancer-related death worldwide, with a poor response to current chemotherapy. Danusertib is a pan-inhibitor of the Aurora kinases and a third-generation Bcr-Abl tyrosine kinase inhibitor with potent anticancer effects, but its antitumor effect and underlying mechanisms in the treatment of human gastric cancer are unknown. This study aimed to investigate the effects of danusertib on cell growth, apoptosis, autophagy, and epithelial to mesenchymal transition and the molecular mechanisms involved in human gastric cancer AGS and NCI-N78 cells. The results showed that danusertib had potent growth-inhibitory, apoptosis-inducing, and autophagy-inducing effects on AGS and NCI-N78 cells. Danusertib arrested AGS and NCI-N78 cells in G2/M phase, with downregulation of expression of cyclin B1 and cyclin-dependent kinase 1 and upregulation of expression of p21 Waf1/Cip1, p27 Kip1, and p53. Danusertib induced mitochondria-mediated apoptosis, with an increase in expression of proapoptotic protein and a decrease in antiapoptotic proteins in both cell lines. Danusertib induced release of cytochrome c from the mitochondria to the cytosol and triggered activation of caspase 9 and caspase 3 in AGS and NCI-N78 cells. Further, danusertib induced autophagy, with an increase in expression of beclin 1 and conversion of microtubule-associated protein 1A/1B-light chain 3 (LC3-I) to LC3-II in both cell lines. Inhibition of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) and p38 mitogen-activated protein kinase pathways as well as activation of 5′ AMP-activated protein kinase contributed to the proautophagic effect of danusertib in AGS and NCI-N78 cells. SB202191 and wortmannin enhanced the autophagy-inducing effect of danusertib in AGS and NCI-N78 cells. In addition, danusertib inhibited epithelial to mesenchymal transition with an increase in expression of E-cadherin and a decrease in expression

  12. Ibogaine-associated cardiac arrest and death: case report and review of the literature.

    PubMed

    Meisner, Jessica A; Wilcox, Susan R; Richards, Jeremy B

    2016-04-01

    A naturally occurring hallucinogenic plant alkaloid, ibogaine has been used as an adjuvant for opiate withdrawal for the past 50 years. In the setting of an escalating nationwide opiate epidemic, use of substances such as ibogaine may also increase. Therefore, familiarity with the mechanisms and potential adverse effects of ibogaine is important for clinicians. We present the case report of a man whose use of ibogaine resulted in cardiac arrest and death, complemented by a review of the literature regarding ibogaine's clinical effects. A 40-year-old man who used ibogaine for symptoms of heroin withdrawal suffered acute cardiac arrest leading to cerebral edema and brain death. His presentation was consistent with ibogaine-induced cardiotoxicity and ibogaine-induced cardiac arrest, and a review of the literature regarding the history, mechanisms, risks and clinical outcomes associated with ibogaine is presented. The case presented underscores the significant potential clinical risks of ibogaine. It is important the healthcare community be aware of the possible effects of ibogaine such that clinicians can provide informed counseling to their patients regarding the risks of attempting detoxification with ibogaine. PMID:27141291

  13. Ibogaine-associated cardiac arrest and death: case report and review of the literature

    PubMed Central

    Meisner, Jessica A.; Wilcox, Susan R.; Richards, Jeremy B.

    2016-01-01

    A naturally occurring hallucinogenic plant alkaloid, ibogaine has been used as an adjuvant for opiate withdrawal for the past 50 years. In the setting of an escalating nationwide opiate epidemic, use of substances such as ibogaine may also increase. Therefore, familiarity with the mechanisms and potential adverse effects of ibogaine is important for clinicians. We present the case report of a man whose use of ibogaine resulted in cardiac arrest and death, complemented by a review of the literature regarding ibogaine’s clinical effects. A 40-year-old man who used ibogaine for symptoms of heroin withdrawal suffered acute cardiac arrest leading to cerebral edema and brain death. His presentation was consistent with ibogaine-induced cardiotoxicity and ibogaine-induced cardiac arrest, and a review of the literature regarding the history, mechanisms, risks and clinical outcomes associated with ibogaine is presented. The case presented underscores the significant potential clinical risks of ibogaine. It is important the healthcare community be aware of the possible effects of ibogaine such that clinicians can provide informed counseling to their patients regarding the risks of attempting detoxification with ibogaine. PMID:27141291

  14. TGEV nucleocapsid protein induces cell cycle arrest and apoptosis through activation of p53 signaling

    SciTech Connect

    Ding, Li; Huang, Yong; Du, Qian; Dong, Feng; Zhao, Xiaomin; Zhang, Wenlong; Xu, Xingang; Tong, Dewen

    2014-03-07

    Highlights: • TGEV N protein reduces cell viability by inducing cell cycle arrest and apoptosis. • TGEV N protein induces cell cycle arrest and apoptosis by regulating p53 signaling. • TGEV N protein plays important roles in TGEV-induced cell cycle arrest and apoptosis. - Abstract: Our previous studies showed that TGEV infection could induce cell cycle arrest and apoptosis via activation of p53 signaling in cultured host cells. However, it is unclear which viral gene causes these effects. In this study, we investigated the effects of TGEV nucleocapsid (N) protein on PK-15 cells. We found that TGEV N protein suppressed cell proliferation by causing cell cycle arrest at the S and G2/M phases and apoptosis. Characterization of various cellular proteins that are involved in regulating cell cycle progression demonstrated that the expression of N gene resulted in an accumulation of p53 and p21, which suppressed cyclin B1, cdc2 and cdk2 expression. Moreover, the expression of TGEV N gene promoted translocation of Bax to mitochondria, which in turn caused the release of cytochrome c, followed by activation of caspase-3, resulting in cell apoptosis in the transfected PK-15 cells following cell cycle arrest. Further studies showed that p53 inhibitor attenuated TGEV N protein induced cell cycle arrest at S and G2/M phases and apoptosis through reversing the expression changes of cdc2, cdk2 and cyclin B1 and the translocation changes of Bax and cytochrome c induced by TGEV N protein. Taken together, these results demonstrated that TGEV N protein might play an important role in TGEV infection-induced p53 activation and cell cycle arrest at the S and G2/M phases and apoptosis occurrence.

  15. The Stringent Response and Cell Cycle Arrest in Escherichia coli

    PubMed Central

    Ferullo, Daniel J.; Lovett, Susan T.

    2008-01-01

    The bacterial stringent response, triggered by nutritional deprivation, causes an accumulation of the signaling nucleotides pppGpp and ppGpp. We characterize the replication arrest that occurs during the stringent response in Escherichia coli. Wild type cells undergo a RelA-dependent arrest after treatment with serine hydroxamate to contain an integer number of chromosomes and a replication origin-to-terminus ratio of 1. The growth rate prior to starvation determines the number of chromosomes upon arrest. Nucleoids of these cells are decondensed; in the absence of the ability to synthesize ppGpp, nucleoids become highly condensed, similar to that seen after treatment with the translational inhibitor chloramphenicol. After induction of the stringent response, while regions corresponding to the origins of replication segregate, the termini remain colocalized in wild-type cells. In contrast, cells arrested by rifampicin and cephalexin do not show colocalized termini, suggesting that the stringent response arrests chromosome segregation at a specific point. Release from starvation causes rapid nucleoid reorganization, chromosome segregation, and resumption of replication. Arrest of replication and inhibition of colony formation by ppGpp accumulation is relieved in seqA and dam mutants, although other aspects of the stringent response appear to be intact. We propose that DNA methylation and SeqA binding to non-origin loci is necessary to enforce a full stringent arrest, affecting both initiation of replication and chromosome segregation. This is the first indication that bacterial chromosome segregation, whose mechanism is not understood, is a step that may be regulated in response to environmental conditions. PMID:19079575

  16. The stringent response and cell cycle arrest in Escherichia coli.

    PubMed

    Ferullo, Daniel J; Lovett, Susan T

    2008-12-01

    The bacterial stringent response, triggered by nutritional deprivation, causes an accumulation of the signaling nucleotides pppGpp and ppGpp. We characterize the replication arrest that occurs during the stringent response in Escherichia coli. Wild type cells undergo a RelA-dependent arrest after treatment with serine hydroxamate to contain an integer number of chromosomes and a replication origin-to-terminus ratio of 1. The growth rate prior to starvation determines the number of chromosomes upon arrest. Nucleoids of these cells are decondensed; in the absence of the ability to synthesize ppGpp, nucleoids become highly condensed, similar to that seen after treatment with the translational inhibitor chloramphenicol. After induction of the stringent response, while regions corresponding to the origins of replication segregate, the termini remain colocalized in wild-type cells. In contrast, cells arrested by rifampicin and cephalexin do not show colocalized termini, suggesting that the stringent response arrests chromosome segregation at a specific point. Release from starvation causes rapid nucleoid reorganization, chromosome segregation, and resumption of replication. Arrest of replication and inhibition of colony formation by ppGpp accumulation is relieved in seqA and dam mutants, although other aspects of the stringent response appear to be intact. We propose that DNA methylation and SeqA binding to non-origin loci is necessary to enforce a full stringent arrest, affecting both initiation of replication and chromosome segregation. This is the first indication that bacterial chromosome segregation, whose mechanism is not understood, is a step that may be regulated in response to environmental conditions. PMID:19079575

  17. Deoxyelephantopin from Elephantopus scaber L. induces cell-cycle arrest and apoptosis in the human nasopharyngeal cancer CNE cells

    SciTech Connect

    Su, Miaoxian; Chung, Hau Yin; Li, Yaolan

    2011-07-29

    Highlights: {yields} Deoxyelephantopin (ESD) inhibited cell proliferation in the human nasopharyngeal cancer CNE cells. {yields} ESD induced cell cycle arrest in S and G2/M phases via modulation of cell cycle regulatory proteins. {yields} ESD triggered apoptosis by dysfunction of mitochondria and induction of both intrinsic and extrinsic apoptotic signaling pathways. {yields} ESD also triggered Akt, ERK, and JNK signaling pathways. -- Abstract: Deoxyelephantopin (ESD), a naturally occurring sesquiterpene lactone present in the Chinese medicinal herb, Elephantopus scaber L. exerted anticancer effects on various cultured cancer cells. However, the cellular mechanisms by which it controls the development of the cancer cells are unavailable, particularly the human nasopharyngeal cancer CNE cells. In this study, we found that ESD inhibited the CNE cell proliferation. Cell cycle arrest in S and G2/M phases was also found. Western blotting analysis showed that modulation of cell cycle regulatory proteins was responsible for the ESD-induced cell cycle arrest. Besides, ESD also triggered apoptosis in CNE cells. Dysfunction in mitochondria was found to be associated with the ESD-induced apoptosis as evidenced by the loss of mitochondrial membrane potential ({Delta}{Psi}m), the translocation of cytochrome c, and the regulation of Bcl-2 family proteins. Despite the Western blotting analysis showed that both intrinsic and extrinsic apoptotic pathways (cleavage of caspases-3, -7, -8, -9, and -10) were triggered in the ESD-induced apoptosis, additional analysis also showed that the induction of apoptosis could be achieved by the caspase-independent manner. Besides, Akt, ERK and JNK pathways were found to involve in ESD-induced cell death. Overall, our findings provided the first evidence that ESD induced cell cycle arrest, and apoptosis in CNE cells. ESD could be a potential chemotherapeutic agent in the treatment of nasopharyngeal cancer (NPC).

  18. High-frequency ultrasound analysis of post-mitotic arrest cell death

    PubMed Central

    Pasternak, Maurice M.; Wirtzfeld, Lauren A.; Kolios, Michael C.; Czarnota, Gregory J.

    2016-01-01

    Non-invasive monitoring of cancer cell death would permit rapid feedback on treatment response. One technique showing such promise is quantitative ultrasound. High-frequency ultrasound spectral radiofrequency analysis was used to study cell death in breast cancer cell samples. Quantitative ultrasound parameters, including attenuation, spectral slope, spectral 0-MHz-intercept, midband fit, and fitted parameters displayed significant changes with paclitaxel-induced cell death, corresponding to observations of morphological changes seen in histology and electron microscopy. In particular, a decrease in spectral slope from 0.24±0.07 dB/MHz to 0.04±0.09 dB/MHz occurred over 24 hours of treatment time and was identified as an ultrasound parameter capable of differentiating post-mitotic arrest cell death from classical apoptosis. The formation of condensed chromatin aggregates of 1 micron or greater in size increased the number of intracellular scatterers, consistent with a hypothesis that nuclear material is a primary source of ultrasound scattering in dying cells. It was demonstrated that the midband fit quantitatively correlated to cell death index, with a Pearson R-squared value of 0.99 at p<0.01. These results suggest that high-frequency ultrasound can not only qualitatively assess the degree of cancer cell death, but may be used to quantify the efficacy of chemotherapeutic treatments. PMID:27226984

  19. The p75{sup NTR} tumor suppressor induces cell cycle arrest facilitating caspase mediated apoptosis in prostate tumor cells

    SciTech Connect

    Khwaja, Fatima; Tabassum, Arshia; Allen, Jeff; Djakiew, Daniel . E-mail: djakiewd@georgetown.edu

    2006-03-24

    The p75 neurotrophin receptor (p75{sup NTR}) is a death receptor which belongs to the tumor necrosis factor receptor super-family of membrane proteins. This study shows that p75{sup NTR} retarded cell cycle progression by induced accumulation of cells in G0/G1 and a reduction in the S phase of the cell cycle. The rescue of tumor cells from cell cycle progression by a death domain deleted ({delta}DD) dominant-negative antagonist of p75{sup NTR} showed that the death domain transduced anti-proliferative activity in a ligand-independent manner. Conversely, addition of NGF ligand rescued retardation of cell cycle progression with commensurate changes in components of the cyclin/cdk holoenzyme complex. In the absence of ligand, p75{sup NTR}-dependent cell cycle arrest facilitated an increase in apoptotic nuclear fragmentation of the prostate cancer cells. Apoptosis of p75{sup NTR} expressing cells occurred via the intrinsic mitochondrial pathway leading to a sequential caspase-9 and -7 cascade. Since the death domain deleted dominant-negative antagonist of p75{sup NTR} rescued intrinsic caspase associated apoptosis in PC-3 cells, this shows p75{sup NTR} was integral to ligand independent induction of apoptosis. Moreover, the ability of ligand to ameliorate the p75{sup NTR}-dependent intrinsic apoptotic cascade indicates that NGF functioned as a survival factor for p75{sup NTR} expressing prostate cancer cells.

  20. Zerumbone, a Sesquiterpene, Controls Proliferation and Induces Cell Cycle Arrest in Human Laryngeal Carcinoma Cell Line Hep-2.

    PubMed

    Jegannathan, Srimathi Devi; Arul, Santhosh; Dayalan, Haripriya

    2016-07-01

    Zerumbone (ZER), a sesquiterpene found in Zingiber zerumbet Smith, has been shown to possess antiproliferative, anticancer, antioxidant, and anti-inflammatory activity against various types of human carcinoma. The molecular mechanism by which ZER mediates its activity against many cancer types is revealed by many studies. Upregulation of proapoptotic molecules and suppression of antiapoptotic gene expression are few of the mechanisms by which ZER mediates its effect. The present study is focused on investigating the effect of ZER on proliferation of laryngeal carcinoma cells (Hep-2). MTT assay results showed that ZER (0.01-100 μM) induced death of Hep-2 cells in a concentration-dependent manner; significant suppression of proliferation of Hep-2 cells was seen with a IC50 value of 15 µM. ZER at a concentration of 15 and 30 μM for 48 h showed early signs of apoptosis as evidenced by confocal microscopy imaging. Flow cytometry studies showed that ZER induced cell cycle arrest. ZER arrested Hep-2 proliferation at S and G2/M phases of cell cycle. In conclusion, these results indicate that ZER has antiproliferative effect and arrests cell cycle in Hep-2 cells in vitro. This could be a potential anticancer drug against laryngeal carcinoma. PMID:27045964

  1. The costs of a suburban paramedic program in reducing deaths due to cardiac arrest.

    PubMed

    Urban, N; Bergner, L; Eisenberg, M S

    1981-04-01

    The marginal costs per averted death of a suburban paramedic program are estimated to be approximately $42,000, when program costs are attributed entirely to cardiac arrest cases due to underlying heart disease, and indirect costs attributable to episode-related hospitalization are included, It is suggested that at $42,000 per cardiac arrest death averted the program is cost-beneficial by two criteria. First, it compares favorably with an estimate obtained from the literature of the value to the average individual of saving the life of a myocardial infarction patient. Second, the people of King County passed a cost-commensurate Paramedic Program Property Tax Levy in 1979, revealing their willingness to support the program. Results of the study should be generalized in accordance with the facts that in King County 1) the population density averages approximately 1,300 per square mile; 2) a basic emergency medical system ensures a 4-minute average response time to initiation of cardiopulmonary resuscitation; 3) a citizen-training program in cardiopulmonary resuscitation further reduces average time to initiation of basic life support; and 4) the paramedic program is designed to ensure a 10-minute average time to definitive care. PMID:6785539

  2. Cell Cycle Arrest in G2/M Promotes Early Steps of Infection by Human Immunodeficiency Virus

    PubMed Central

    Groschel, Bettina; Bushman, Frederic

    2005-01-01

    We have identified four small molecules that boost transduction of cells by human immunodeficiency virus (HIV) and investigated their mechanism of action. These molecules include etoposide and camptothecin, which induce DNA damage by inhibiting religation of cleaved topoisomerase-DNA complexes, taxol, which interferes with the function of microtubules, and aphidicolin, which inhibits DNA polymerases. All four compounds arrest the cell cycle at G2/M, though in addition high concentrations of aphidicolin arrest in G1. We find that early events of HIV replication, including synthesis of late reverse transcription products, two-long terminal repeat circles, and integrated proviruses, were increased after treatment of cells with concentrations of each compound that arrested in G2/M. Stimulation was seen for both transformed cell lines (293T and HeLa cells) and primary cells (IMR90 lung fibroblasts). Arrest in G1 with high concentrations of aphidicolin boosted transduction, though not much as with lower concentrations that arrested in G2/M. Arrest of IMR90 cells in G1 by serum starvation and contact inhibition reduced transduction. Previously, the proteasome inhibitor MG132 was reported to increase HIV infection—here we investigated the effects of combinations of the cell cycle inhibitors with MG132 and obtained data suggesting that MG132 may also boost transduction by causing G2/M cell cycle arrest. These data document that cell cycle arrest in G2/M boosts the early steps of HIV infection and suggests methods for increasing transduction with HIV-based vectors. PMID:15827184

  3. Induction of Apoptosis and Antiproliferative Activity of Naringenin in Human Epidermoid Carcinoma Cell through ROS Generation and Cell Cycle Arrest

    PubMed Central

    Jafri, Asif; Ahmad, Sheeba; Afzal, Mohammad; Arshad, Md

    2014-01-01

    A natural predominant flavanone naringenin, especially abundant in citrus fruits, has a wide range of pharmacological activities. The search for antiproliferative agents that reduce skin carcinoma is a task of great importance. The objective of this study was to analyze the anti-proliferative and apoptotic mechanism of naringenin using MTT assay, DNA fragmentation, nuclear condensation, change in mitochondrial membrane potential, cell cycle kinetics and caspase-3 as biomarkers and to investigate the ability to induce reactive oxygen species (ROS) initiating apoptotic cascade in human epidermoid carcinoma A431 cells. Results showed that naringenin exposure significantly reduced the cell viability of A431 cells (p<0.01) with a concomitant increase in nuclear condensation and DNA fragmentation in a dose dependent manner. The intracellular ROS generation assay showed statistically significant (p<0.001) dose-related increment in ROS production for naringenin. It also caused naringenin-mediated epidermoid carcinoma apoptosis by inducing mitochondrial depolarization. Cell cycle study showed that naringenin induced cell cycle arrest in G0/G1 phase of cell cycle and caspase-3 analysis revealed a dose dependent increment in caspase-3 activity which led to cell apoptosis. This study confirms the efficacy of naringenin that lead to cell death in epidermoid carcinoma cells via inducing ROS generation, mitochondrial depolarization, nuclear condensation, DNA fragmentation, cell cycle arrest in G0/G1 phase and caspase-3 activation. PMID:25330158

  4. Connexin arrests the cell cycle through cytosolic retention of an E3 ligase.

    PubMed

    Shi, Qian; Jiang, Jean X

    2016-03-01

    The gap junction proteins connexins play important roles in cell growth and differentiation; however, the underlying mechanism remains largely elusive. We recently identified a channel-independent role of connexins in cell cycle control in which connexin 50 directly interacts with S-phase kinase 2 and prevents its nuclear localization, resulting in p27/p57 protection and cell cycle arrest. PMID:27308638

  5. Difference of cell cycle arrests induced by lidamycin in human breast cancer cells.

    PubMed

    Liu, Xia; He, Hongwei; Feng, Yun; Zhang, Min; Ren, Kaihuan; Shao, Rongguang

    2006-02-01

    Lidamycin (LDM) is a member of the enediyne antibiotic family. It is undergoing phase I clinical trials in China as a potential chemotherapeutic agent. In the present study, we investigated the mechanism by which LDM induced cell cycle arrest in human breast cancer cells. The results showed that LDM induced G1 arrest in p53 wild-type MCF-7 cells at low concentrations, and caused both G1 and G2/M arrests at higher concentrations. In contrast, LDM induced only G2/M arrest in p53-mutant MCF-7/DOX cells. Western blotting analysis indicated that LDM-induced G1 and G2/M arrests in MCF-7 cells were associated with an increase of p53 and p21, and a decrease of phosphorylated retinoblastoma tumor suppressor protein, cyclin-dependent kinase (Cdk), Cdc2 and cyclin B1 protein levels. However, LDM-induced G2/M arrest in MCF-7/DOX cells was correlated with the reduction of cyclin B1 expression. Further study indicated that the downregulation of cyclin B1 by LDM in MCF-7 cells was associated with decreasing cyclin B1 mRNA levels and promoting protein degradation, whereas it was only due to inducing cyclin B1 protein degradation in MCF-7/DOX cells. In addition, activation of checkpoint kinases Chk1 or Chk2 maybe contributed to LDM-induced cell cycle arrest. Taken together, we provide the first evidence that LDM induces different cell cycle arrests in human breast cancer cells, which are dependent on drug concentration and p53 status. These findings are helpful in understanding the molecular anti-cancer mechanisms of LDM and support its clinical trials. PMID:16428935

  6. Astaxanthin Inhibits Proliferation and Induces Apoptosis and Cell Cycle Arrest of Mice H22 Hepatoma Cells.

    PubMed

    Shao, Yiye; Ni, Yanbo; Yang, Jing; Lin, Xutao; Li, Jun; Zhang, Lixia

    2016-01-01

    BACKGROUND It is widely recognized that astaxanthin (ASX), a member of the carotenoid family, has strong biological activities including antioxidant, anti-inflammation, and immune-modulation activities. Previous studies have confirmed that ASX can effectively inhibit hepatoma cells in vitro. MATERIAL AND METHODS MTT was used to assay proliferation of mice H22 cells, and flow cytometry was used to determine apoptosis and cell cycle arrest of H22 cells in vitro and in vivo. Moreover, anti-tumor activity of ASX was observed in mice. RESULTS ASX inhibited the proliferation of H22 cells, promoted cell necrosis, and induced cell cycle arrest in G2 phase in vitro and in vivo. CONCLUSIONS This study indicated that ASX can inhibit proliferation and induce apoptosis and cell cycle arrest in mice H22 hepatoma cells in vitro and in vivo. PMID:27333866

  7. Astaxanthin Inhibits Proliferation and Induces Apoptosis and Cell Cycle Arrest of Mice H22 Hepatoma Cells

    PubMed Central

    Shao, Yiye; Ni, Yanbo; Yang, Jing; Lin, Xutao; Li, Jun; Zhang, Lixia

    2016-01-01

    Background It is widely recognized that astaxanthin (ASX), a member of the carotenoid family, has strong biological activities including antioxidant, anti-inflammation, and immune-modulation activities. Previous studies have confirmed that ASX can effectively inhibit hepatoma cells in vitro. Material/Methods MTT was used to assay proliferation of mice H22 cells, and flow cytometry was used to determine apoptosis and cell cycle arrest of H22 cells in vitro and in vivo. Moreover, anti-tumor activity of ASX was observed in mice. Results ASX inhibited the proliferation of H22 cells, promoted cell necrosis, and induced cell cycle arrest in G2 phase in vitro and in vivo. Conclusions This study indicated that ASX can inhibit proliferation and induce apoptosis and cell cycle arrest in mice H22 hepatoma cells in vitro and in vivo. PMID:27333866

  8. G1/S Cell Cycle Arrest Provides Anoikis Resistance through Erk-Mediated Bim Suppression†

    PubMed Central

    Collins, Nicole L.; Reginato, Maurico J.; Paulus, Jessica K.; Sgroi, Dennis C.; LaBaer, Joshua; Brugge, Joan S.

    2005-01-01

    Proper attachment to the extracellular matrix is essential for cell survival. Detachment from the extracellular matrix results in an apoptotic process termed anoikis. Anoikis induction in MCF-10A mammary epithelial cells is due not only to loss of survival signals following integrin disengagement, but also to consequent downregulation of epidermal growth factor (EGFR) and loss of EGFR-induced survival signals. Here we demonstrate that G1/S arrest by overexpression of the cyclin-dependent kinase inhibitors p16INK4a, p21Cip1, or p27Kip1 or by treatment with mimosine or aphidicolin confers anoikis resistance in MCF-10A cells. G1/S arrest-mediated anoikis resistance involves suppression of the BH3-only protein Bim. Furthermore, in G1/S-arrested cells, Erk phosphorylation is maintained in suspension and is necessary for Bim suppression. Following G1/S arrest, known proteins upstream of Erk, including Raf and Mek, are not activated. However, retained Erk activation under conditions in which Raf and Mek activation is lost is observed, suggesting that G1/S arrest acts at the level of Erk dephosphorylation. Thus, anoikis resistance by G1/S arrest is mediated by a mechanism involving Bim suppression through maintenance of Erk activation. These results provide a novel link between cell cycle arrest and survival, and this mechanism could contribute to the survival of nonreplicating, dormant tumor cells that avert apoptosis during early stages of metastasis. PMID:15923641

  9. Lithium increases proliferation of hippocampal neural stem/progenitor cells and rescues irradiation-induced cell cycle arrest in vitro.

    PubMed

    Zanni, Giulia; Di Martino, Elena; Omelyanenko, Anna; Andäng, Michael; Delle, Ulla; Elmroth, Kecke; Blomgren, Klas

    2015-11-10

    Radiotherapy in children causes debilitating cognitive decline, partly linked to impaired neurogenesis. Irradiation targets primarily cancer cells but also endogenous neural stem/progenitor cells (NSPCs) leading to cell death or cell cycle arrest. Here we evaluated the effects of lithium on proliferation, cell cycle and DNA damage after irradiation of young NSPCs in vitro.NSPCs were treated with 1 or 3 mM LiCl and we investigated proliferation capacity (neurosphere volume and bromodeoxyuridine (BrdU) incorporation). Using flow cytometry, we analysed apoptosis (annexin V), cell cycle (propidium iodide) and DNA damage (γH2AX) after irradiation (3.5 Gy) of lithium-treated NSPCs.Lithium increased BrdU incorporation and, dose-dependently, the number of cells in replicative phase as well as neurosphere growth. Irradiation induced cell cycle arrest in G1 and G2/M phases. Treatment with 3 mM LiCl was sufficient to increase NSPCs in S phase, boost neurosphere growth and reduce DNA damage. Lithium did not affect the levels of apoptosis, suggesting that it does not rescue NSPCs committed to apoptosis due to accumulated DNA damage.Lithium is a very promising candidate for protection of the juvenile brain from radiotherapy and for its potential to thereby improve the quality of life for those children who survive their cancer. PMID:26397227

  10. Lithium increases proliferation of hippocampal neural stem/progenitor cells and rescues irradiation-induced cell cycle arrest in vitro

    PubMed Central

    Omelyanenko, Anna; Andäng, Michael; Delle, Ulla; Elmroth, Kecke; Blomgren, Klas

    2015-01-01

    Radiotherapy in children causes debilitating cognitive decline, partly linked to impaired neurogenesis. Irradiation targets primarily cancer cells but also endogenous neural stem/progenitor cells (NSPCs) leading to cell death or cell cycle arrest. Here we evaluated the effects of lithium on proliferation, cell cycle and DNA damage after irradiation of young NSPCs in vitro. NSPCs were treated with 1 or 3 mM LiCl and we investigated proliferation capacity (neurosphere volume and bromodeoxyuridine (BrdU) incorporation). Using flow cytometry, we analysed apoptosis (annexin V), cell cycle (propidium iodide) and DNA damage (γH2AX) after irradiation (3.5 Gy) of lithium-treated NSPCs. Lithium increased BrdU incorporation and, dose-dependently, the number of cells in replicative phase as well as neurosphere growth. Irradiation induced cell cycle arrest in G1 and G2/M phases. Treatment with 3 mM LiCl was sufficient to increase NSPCs in S phase, boost neurosphere growth and reduce DNA damage. Lithium did not affect the levels of apoptosis, suggesting that it does not rescue NSPCs committed to apoptosis due to accumulated DNA damage. Lithium is a very promising candidate for protection of the juvenile brain from radiotherapy and for its potential to thereby improve the quality of life for those children who survive their cancer. PMID:26397227

  11. Alisertib Induces Cell Cycle Arrest, Apoptosis, Autophagy and Suppresses EMT in HT29 and Caco-2 Cells

    PubMed Central

    Ren, Bao-Jun; Zhou, Zhi-Wei; Zhu, Da-Jian; Ju, Yong-Le; Wu, Jin-Hao; Ouyang, Man-Zhao; Chen, Xiao-Wu; Zhou, Shu-Feng

    2015-01-01

    Colorectal cancer (CRC) is one of the most common malignancies worldwide with substantial mortality and morbidity. Alisertib (ALS) is a selective Aurora kinase A (AURKA) inhibitor with unclear effect and molecular interactome on CRC. This study aimed to evaluate the molecular interactome and anticancer effect of ALS and explore the underlying mechanisms in HT29 and Caco-2 cells. ALS markedly arrested cells in G2/M phase in both cell lines, accompanied by remarkable alterations in the expression level of key cell cycle regulators. ALS induced apoptosis in HT29 and Caco-2 cells through mitochondrial and death receptor pathways. ALS also induced autophagy in HT29 and Caco-2 cells, with the suppression of phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR), but activation of 5′ AMP-activated protein kinase (AMPK) signaling pathways. There was a differential modulating effect of ALS on p38 MAPK signaling pathway in both cell lines. Moreover, induction or inhibition of autophagy modulated basal and ALS-induced apoptosis in both cell lines. ALS potently suppressed epithelial to mesenchymal transition (EMT) in HT29 and Caco-2 cells. Collectively, it suggests that induction of cell cycle arrest, promotion of apoptosis and autophagy, and suppression of EMT involving mitochondrial, death receptor, PI3K/Akt/mTOR, p38 MAPK, and AMPK signaling pathways contribute to the cancer cell killing effect of ALS on CRC cells. PMID:26729093

  12. The nonstructural protein NP1 of human bocavirus 1 induces cell cycle arrest and apoptosis in Hela cells

    SciTech Connect

    Sun, Bin; Cai, Yingyue; Li, Yongshu; Li, Jingjing; Liu, Kaiyu; Li, Yi; Yang, Yongbo

    2013-05-25

    Human bocavirus type 1 (HBoV1) is a newly identified pathogen associated with human respiratory tract illnesses. Previous studies demonstrated that proteins of HBoV1 failed to cause cell death, which is considered as a possible common feature of bocaviruses. However, our work showed that the NP1 of HBoV1 induced apoptotic cell death in Hela cells in the absence of viral genome replication and expression of other viral proteins. Mitochondria apoptotic pathway was involved in the NP1-induced apoptosis that was confirmed by apoptotic characteristics including morphological changes, DNA fragmentation and caspase activation. We also demonstrated that the cell cycle of NP1-transfected Hela cells was transiently arrested at G2/M phase followed by rapid appearance of apoptosis and that the N terminal domain of NP1 was critical to its nuclear localization and function in apoptosis induction in Hela cells. These findings might provide alternative information for further study of mechanism of HBoV1 pathogenesis. - Highlights: ► NP1 protein of HBoV1 induced apoptosis in Hela cells was first reported. ► NP1 induced-apoptosis followed the cell cycle arrest at G2/M phase. ► The NP1 induced-apoptosis was mediated by mitochondrion apoptotic pathway. ► N terminal of NP1 was critical for apoptosis induction and nuclear localization.

  13. Sulforaphane Induces Cell Cycle Arrest and Apoptosis in Acute Lymphoblastic Leukemia Cells

    PubMed Central

    Suppipat, Koramit; Park, Chun Shik; Shen, Ye; Zhu, Xiao; Lacorazza, H. Daniel

    2012-01-01

    Acute lymphoblastic leukemia (ALL) is the most common hematological cancer in children. Although risk-adaptive therapy, CNS-directed chemotherapy, and supportive care have improved the survival of ALL patients, disease relapse is still the leading cause of cancer-related death in children. Therefore, new drugs are needed as frontline treatments in high-risk disease and as salvage agents in relapsed ALL. In this study, we report that purified sulforaphane, a natural isothiocyanate found in cruciferous vegetables, has anti-leukemic properties in a broad range of ALL cell lines and primary lymphoblasts from pediatric T-ALL and pre-B ALL patients. The treatment of ALL leukemic cells with sulforaphane resulted in dose-dependent apoptosis and G2/M cell cycle arrest, which was associated with the activation of caspases (3, 8, and 9), inactivation of PARP, p53-independent upregulation of p21CIP1/WAF1, and inhibition of the Cdc2/Cyclin B1 complex. Interestingly, sulforaphane also inhibited the AKT and mTOR survival pathways in most of the tested cell lines by lowering the levels of both total and phosphorylated proteins. Finally, the administration of sulforaphane to the ALL xenograft models resulted in a reduction of tumor burden, particularly following oral administration, suggesting a potential role as an adjunctive agent to improve the therapeutic response in high-risk ALL patients with activated AKT signaling. PMID:23251470

  14. Cell Cycle Arrest and Cell Survival Induce Reverse Trends of Cardiolipin Remodeling

    PubMed Central

    Chao, Yu-Jen; Chang, Wan-Hsin; Ting, Hsiu-Chi; Chao, Wei-Ting; Hsu, Yuan-Hao Howard

    2014-01-01

    Cell survival from the arrested state can be a cause of the cancer recurrence. Transition from the arrest state to the growth state is highly regulated by mitochondrial activity, which is related to the lipid compositions of the mitochondrial membrane. Cardiolipin is a critical phospholipid for the mitochondrial integrity and functions. We examined the changes of cardiolipin species by LC-MS in the transition between cell cycle arrest and cell reviving in HT1080 fibrosarcoma cells. We have identified 41 cardiolipin species by MS/MS and semi-quantitated them to analyze the detailed changes of cardiolipin species. The mass spectra of cardiolipin with the same carbon number form an envelope, and the C64, C66, C68, C70 C72 and C74 envelopes in HT1080 cells show a normal distribution in the full scan mass spectrum. The cardiolipin quantity in a cell decreases while entering the cell cycle arrest, but maintains at a similar level through cell survival. While cells awakening from the arrested state and preparing itself for replication, the groups with short acyl chains, such as C64, C66 and C68 show a decrease of cardiolipin percentage, but the groups with long acyl chains, such as C70 and C72 display an increase of cardiolipin percentage. Interestingly, the trends of the cardiolipin species changes during the arresting state are completely opposite to cell growing state. Our results indicate that the cardiolipin species shift from the short chain to long chain cardiolipin during the transition from cell cycle arrest to cell progression. PMID:25422939

  15. Glucose restriction induces transient G2 cell cycle arrest extending cellular chronological lifespan.

    PubMed

    Masuda, Fumie; Ishii, Mahiro; Mori, Ayaka; Uehara, Lisa; Yanagida, Mitsuhiro; Takeda, Kojiro; Saitoh, Shigeaki

    2016-01-01

    While glucose is the fundamental source of energy in most eukaryotes, it is not always abundantly available in natural environments, including within the human body. Eukaryotic cells are therefore thought to possess adaptive mechanisms to survive glucose-limited conditions, which remain unclear. Here, we report a novel mechanism regulating cell cycle progression in response to abrupt changes in extracellular glucose concentration. Upon reduction of glucose in the medium, wild-type fission yeast cells undergo transient arrest specifically at G2 phase. This cell cycle arrest is dependent on the Wee1 tyrosine kinase inhibiting the key cell cycle regulator, CDK1/Cdc2. Mutant cells lacking Wee1 are not arrested at G2 upon glucose limitation and lose viability faster than the wild-type cells under glucose-depleted quiescent conditions, suggesting that this cell cycle arrest is required for extension of chronological lifespan. Our findings indicate the presence of a novel cell cycle checkpoint monitoring glucose availability, which may be a good molecular target for cancer therapy. PMID:26804466

  16. Using Drosophila Larval Imaginal Discs to Study Low-Dose Radiation-Induced Cell Cycle Arrest

    PubMed Central

    Yan, Shian-Jang; Li, Willis X.

    2012-01-01

    Under genotoxic stress, activation of cell cycle checkpoint responses leads to cell cycle arrest, which allows cells to repair DNA damage before continuing to cycle. Drosophila larval epithelial sacs, called imaginal discs, are an excellent in vivo model system for studying radiation-induced cell cycle arrest. Larval imaginal discs go into cell cycle arrest after being subjected to low-dose irradiation, are subject to easy genetic manipulation, are not crucial for survival of the organism, and can be dissected easily for further molecular or cellular analysis. In this chapter, we describe methods for assessing low-dose irradiation-induced cell cycle arrest. Mitotic cells are identified by immunofluorescence staining for the mitotic marker phosphorylated histone H3 (phospho-histone H3 or pH3). When wandering third-instar control larvae, without transgene expression, are exposed to 500 rads of X-ray or γ-ray irradiation, the number of pH3-positive cells in wing imaginal discs is reduced from hundreds before irradiation to approximately 30 after irradiation, with an equal distribution between the anterior and posterior compartments (Yan et al., 2011, FASEB J). Using the GAL4/UAS system, RNAi, cDNA, or microRNA sponge transgenes can be expressed in the posterior compartment of the wing disc using drivers such as engrailed (en)-Gal4, while the anterior compartment serves as an internal control. This approach makes it possible to do genome-wide genetic screening for molecules involved in radiation-induced cell cycle arrest. PMID:21870287

  17. Using Drosophila larval imaginal discs to study low-dose radiation-induced cell cycle arrest.

    PubMed

    Yan, Shian-Jang; Li, Willis X

    2011-01-01

    Under genotoxic stress, activation of cell cycle checkpoint responses leads to cell cycle arrest, which allows cells to repair DNA damage before continuing to cycle. Drosophila larval epithelial sacs, called imaginal discs, are an excellent in vivo model system for studying radiation-induced cell cycle arrest. Larval imaginal discs go into cell cycle arrest after being subjected to low-dose irradiation, are subject to easy genetic manipulation, are not crucial for survival of the organism, and can be dissected easily for further molecular or cellular analysis. In this chapter, we describe methods for assessing low-dose irradiation-induced cell cycle arrest. Mitotic cells are identified by immunofluorescence staining for the mitotic marker phosphorylated histone H3 (phospho-histone H3 or pH3). When wandering third-instar control larvae, without transgene expression, are exposed to 500 rads of X-ray or γ-ray irradiation, the number of pH3-positive cells in wing imaginal discs is reduced from hundreds before irradiation to approximately 30 after irradiation, with an equal distribution between the anterior and posterior compartments (Yan et al., 2011, FASEB J). Using the GAL4/UAS system, RNAi, cDNA, or microRNA sponge transgenes can be expressed in the posterior compartment of the wing disc using drivers such as engrailed (en)-Gal4, while the anterior compartment serves as an internal control. This approach makes it possible to do genome-wide genetic screening for molecules involved in radiation-induced cell cycle arrest. PMID:21870287

  18. Adenosine induces G2/M cell-cycle arrest by inhibiting cell mitosis progression.

    PubMed

    Jia, Kun-Zhi; Tang, Bo; Yu, Lu; Cheng, Wei; Zhang, Rong; Zhang, Jian-Fa; Hua, Zi-Chun

    2010-01-01

    Cellular adenosine accumulates under stress conditions. Few papers on adenosine are concerned with its function in the cell cycle. The cell cycle is the essential mechanism by which all living things reproduce and the target machinery when cells encounter stresses, so it is necessary to examine the relationship between adenosine and the cell cycle. In the present study, adenosine was found to induce G-2/M cell-cycle arrest. Furthermore, adenosine was found to modulate the expression of some important proteins in the cell cycle, such as cyclin B and p21, and to inhibit the transition of metaphase to anaphase in mitosis. PMID:19947935

  19. End-of-life cell cycle arrest contributes to stochasticity of yeast replicative aging.

    PubMed

    Delaney, Joe R; Chou, Annie; Olsen, Brady; Carr, Daniel; Murakami, Christopher; Ahmed, Umema; Sim, Sylvia; An, Elroy H; Castanza, Anthony S; Fletcher, Marissa; Higgins, Sean; Holmberg, Mollie; Hui, Jessica; Jelic, Monika; Jeong, Ki-Soo; Kim, Jin R; Klum, Shannon; Liao, Eric; Lin, Michael S; Lo, Winston; Miller, Hillary; Moller, Richard; Peng, Zhao J; Pollard, Tom; Pradeep, Prarthana; Pruett, Dillon; Rai, Dilreet; Ros, Vanessa; Schleit, Jennifer; Schuster, Alex; Singh, Minnie; Spector, Benjamin L; Sutphin, George L; Wang, Adrienne M; Wasko, Brian M; Vander Wende, Helen; Kennedy, Brian K; Kaeberlein, Matt

    2013-05-01

    There is growing evidence that stochastic events play an important role in determining individual longevity. Studies in model organisms have demonstrated that genetically identical populations maintained under apparently equivalent environmental conditions display individual variation in life span that can be modeled by the Gompertz-Makeham law of mortality. Here, we report that within genetically identical haploid and diploid wild-type populations, shorter-lived cells tend to arrest in a budded state, while cells that arrest in an unbudded state are significantly longer-lived. This relationship is particularly notable in diploid BY4743 cells, where mother cells that arrest in a budded state have a shorter mean life span (25.6 vs. 35.6) and larger coefficient of variance with respect to individual life span (0.42 vs. 0.32) than cells that arrest in an unbudded state. Mutations that cause genomic instability tend to shorten life span and increase the proportion of the population that arrest in a budded state. These observations suggest that randomly occurring damage may contribute to stochasticity during replicative aging by causing a subset of the population to terminally arrest prematurely in the S or G2 phase of the cell cycle. PMID:23336757

  20. End-of-life cell cycle arrest contributes to stochasticity of yeast replicative aging

    PubMed Central

    Delaney, Joe R.; Chou, Annie; Olsen, Brady; Carr, Daniel; Murakami, Christopher; Ahmed, Umema; Sim, Sylvia; An, Elroy H.; Castanza, Anthony S.; Fletcher, Marissa; Higgins, Sean; Holmberg, Mollie; Hui, Jessica; Jelic, Monika; Jeong, Ki-Soo; Kim, Jin R.; Klum, Shannon; Liao, Eric; Lin, Michael S.; Lo, Winston; Miller, Hillary; Moller, Richard; Peng, Zhao J.; Pollard, Tom; Pradeep, Prarthana; Pruett, Dillon; Rai, Dilreet; Ros, Vanessa; Schleit, Jennifer; Schuster, Alex; Singh, Minnie; Spector, Benjamin L.; Sutphin, George L.; Wang, Adrienne M.; Wasko, Brian M.; Wende, Helen Vander; Kennedy, Brian K.; Kaeberlein, Matt

    2013-01-01

    There is growing evidence that stochastic events play an important role in determining individual longevity. Studies in model organisms have demonstrated that genetically identical populations maintained under apparently equivalent environmental conditions display individual variation in lifespan that can be modeled by the Gompertz-Makeham law of mortality. Here we report that within genetically identical haploid and diploid wild type populations, shorter-lived cells tend to arrest in a budded state, while cells that arrest in an unbudded state are significantly longer-lived. This relationship is particularly notable in diploid BY4743 cells, where mother cells that arrest in a budded state have a shorter mean lifespan (25.6 vs. 35.6) and larger coefficient of variance with respect to individual lifespan (0.42 vs. 0.32) than cells that arrest in an unbudded state. Mutations that cause genomic instability tend to shorten lifespan and increase the proportion of the population that arrest in a budded state. These observations suggest that randomly occurring damage may contribute to stochasticity during replicative aging by causing a subset of the population to terminally arrest prematurely in the S or G2 phase of the cell cycle. PMID:23336757

  1. Momordica cochinchinensis Spreng. seed extract suppresses breast cancer growth by inducing cell cycle arrest and apoptosis.

    PubMed

    Zheng, Lei; Zhang, Yanmin; Liu, Yanping; Yang, Xiaoyan Ou; Zhan, Yingzhuan

    2015-10-01

    The herb Momordica cochinchinensis has been used for a variety of purposes, and been shown to have anti‑cancer properties. The present study assessed the potency and the underlying mechanisms of action of the ethyl acetate extract of seeds of Momordica cochinchinensis (ESMC2) on breast cancer cells. Therefore, the effects of ESMC2 on the cell viability, cell cycle and apoptosis of MDA‑MB‑231 cells were investigated. The results showed that ESMC2 exerted a marked growth inhibitory effect on the cells. Cell cycle arrest in G2 phase following treatment with ESMC2 was associated with a marked increase in the protein levels of cyclin B1, cyclin E and cyclin-dependent kinase 1 and a decrease in cyclin D1 expression. In addition, ESMC2 dose‑dependently induced cell apoptosis, which was mediated via upregulation of the apoptosis-associated proteins p53, B-cell lymphoma 2 (Bcl‑2)‑associated X protein, Bcl-2 homologous antagonist killer and Bcl-2-associated death promoter expression, as well as downregulation of nuclear factor kappa B, Bcl‑2 and myeloid cell leukemia‑1. Furthermore, the activation of extracellular signal-regulated kinase 1/2, p38, c-Jun N-terminal kinase (JNK) and Akt phosphorylation were decreased by ESMC2 in a dose‑dependent manner, indicating that ESMC2 exerted its effects via the mitogen-activated protein kinase/JNK pathway. Furthermore, nude mouse xenotransplant models were used to evaluate the tumor growth inhibitory effects of ESMC2. The possible chemical components of ESMC2 were analyzed by gas chromatography-mass spectrometry, and 12 compounds were detected from the major peaks based on the similarity index with entries of a compound database. The results of the present study may aid in the development of novel therapies for breast cancer. PMID:26252798

  2. Unexpected Arrest-Related Deaths in America: 12 Months of Open Source Surveillance

    PubMed Central

    Ho, Jeffrey D.; Heegaard, William G.; Dawes, Donald M.; Natarajan, Sridhar; Reardon, Robert F.; Miner, James R.

    2009-01-01

    Introduction: Sudden, unexpected arrest-related death (ARD) has been associated with drug abuse, extreme delirium or certain police practices. There is insufficient surveillance and causation data available. We report 12 months of surveillance data using a novel data collection methodology. Methods: We used an open-source, prospective method to collect 12 consecutive months of data, including demographics, behavior, illicit substance use, control methods used, and time of collapse after law enforcement contact. Descriptive analysis and chi-square testing were applied. Results: There were 162 ARD events reported that met inclusion criteria. The majority were male with mean age 36 years, and involved bizarre, agitated behavior and reports of drug abuse just prior to death. Law enforcement control techniques included none (14%); empty-hand techniques (69%); intermediate weapons such as TASER® device, impact weapon or chemical irritant spray (52%); and deadly force (12%). Time from contact to subject collapse included instantaneous (13%), within the first hour (53%) and 1–48 hours (35%). Significant collapse time associations occurred with the use of certain intermediate weapons. Conclusion: This surveillance report can be a foundation for discussing ARD. These data support the premise that ARDs primarily occur in persons with a certain demographic and behavior profile that includes middle-aged males exhibiting agitated, bizarre behavior generally following illicit drug abuse. Collapse time associations were demonstrated with the use of TASER devices and impact weapons. We recommend further study in this area to validate our data collection method and findings. PMID:19561821

  3. Cardiac arrest triggers hippocampal neuronal death through autophagic and apoptotic pathways.

    PubMed

    Cui, Derong; Shang, Hanbing; Zhang, Xiaoli; Jiang, Wei; Jia, Xiaofeng

    2016-01-01

    The mechanism of neuronal death induced by ischemic injury remains unknown. We investigated whether autophagy and p53 signaling played a role in the apoptosis of hippocampal neurons following global cerebral ischemia-reperfusion (I/R) injury, in a rat model of 8-min asphyxial cardiac arrest (CA) and resuscitation. Increased autophagosome numbers, expression of lysosomal cathepsin B, cathepsin D, Beclin-1, and microtubule-associated protein light chain 3 (LC3) suggested autophagy in hippocampal cells. The expression of tumor suppressor protein 53 (p53) and its target genes: Bax, p53-upregulated modulator of apoptosis (PUMA), and damage-regulated autophagy modulator (DRAM) were upregulated following CA. The p53-specific inhibitor pifithrin-α (PFT-α) significantly reduced the expression of pro-apoptotic proteins (Bax and PUMA) and autophagic proteins (LC3-II and DRAM) that generally increase following CA. PFT-α also reduced hippocampal neuronal damage following CA. Similarly, 3-methyladenine (3-MA), which inhibits autophagy and bafilomycin A1 (BFA), which inhibits lysosomes, significantly inhibited hippocampal neuronal damage after CA. These results indicate that CA affects both autophagy and apoptosis, partially mediated by p53. Autophagy plays a significant role in hippocampal neuronal death induced by cerebral I/R following asphyxial-CA. PMID:27273382

  4. Cardiac arrest triggers hippocampal neuronal death through autophagic and apoptotic pathways

    PubMed Central

    Cui, Derong; Shang, Hanbing; Zhang, Xiaoli; Jiang, Wei; Jia, Xiaofeng

    2016-01-01

    The mechanism of neuronal death induced by ischemic injury remains unknown. We investigated whether autophagy and p53 signaling played a role in the apoptosis of hippocampal neurons following global cerebral ischemia-reperfusion (I/R) injury, in a rat model of 8-min asphyxial cardiac arrest (CA) and resuscitation. Increased autophagosome numbers, expression of lysosomal cathepsin B, cathepsin D, Beclin-1, and microtubule-associated protein light chain 3 (LC3) suggested autophagy in hippocampal cells. The expression of tumor suppressor protein 53 (p53) and its target genes: Bax, p53-upregulated modulator of apoptosis (PUMA), and damage-regulated autophagy modulator (DRAM) were upregulated following CA. The p53-specific inhibitor pifithrin-α (PFT-α) significantly reduced the expression of pro-apoptotic proteins (Bax and PUMA) and autophagic proteins (LC3-II and DRAM) that generally increase following CA. PFT-α also reduced hippocampal neuronal damage following CA. Similarly, 3-methyladenine (3-MA), which inhibits autophagy and bafilomycin A1 (BFA), which inhibits lysosomes, significantly inhibited hippocampal neuronal damage after CA. These results indicate that CA affects both autophagy and apoptosis, partially mediated by p53. Autophagy plays a significant role in hippocampal neuronal death induced by cerebral I/R following asphyxial-CA. PMID:27273382

  5. Cell-cycle arrest and acute kidney injury: the light and the dark sides

    PubMed Central

    Kellum, John A.; Chawla, Lakhmir S.

    2016-01-01

    Acute kidney injury (AKI) is a common consequence of systemic illness or injury and it complicates several forms of major surgery. Two major difficulties have hampered progress in AKI research and clinical management. AKI is difficult to detect early and its pathogenesis is still poorly understood. We recently reported results from multi-center studies where two urinary markers of cell-cycle arrest, tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) were validated for development of AKI well ahead of clinical manifestations—azotemia and oliguria. Cell-cycle arrest is known to be involved in the pathogenesis of AKI and this ‘dark side’ may also involve progression to chronic kidney disease. However, cell-cycle arrest has a ‘light side’ as well, since this mechanism can protect cells from the disastrous consequences of entering cell division with damaged DNA or insufficient bioenergetic resources during injury or stress. Whether we can use the light side to help prevent AKI remains to be seen, but there is already evidence that cell-cycle arrest biomarkers are indicators of both sides of this complex physiology. PMID:26044835

  6. Aristolochic acid-induced apoptosis and G2 cell cycle arrest depends on ROS generation and MAP kinases activation.

    PubMed

    Romanov, Victor; Whyard, Terry C; Waltzer, Wayne C; Grollman, Arthur P; Rosenquist, Thomas

    2015-01-01

    Ingestion of aristolochic acids (AAs) contained in herbal remedies results in a renal disease and, frequently, urothelial malignancy. The genotoxicity of AA in renal cells, including mutagenic DNA adducts formation, is well documented. However, the mechanisms of AA-induced tubular atrophy and renal fibrosis are largely unknown. To better elucidate some aspects of this process, we studied cell cycle distribution and cell survival of renal epithelial cells treated with AAI at low and high doses. A low dose of AA induces cell cycle arrest in G2/M phase via activation of DNA damage checkpoint pathway ATM-Chk2-p53-p21. DNA damage signaling pathway is activated more likely via increased production of reactive oxygen species (ROS) caused by AA treatment then via DNA damage induced directly by AA. Higher AA concentration induced cell death partly via apoptosis. Since mitogen-activated protein kinases play an important role in cell survival, death and cell cycle progression, we assayed their function in AA-treated renal tubular epithelial cells. ERK1/2 and p38 but not JNK were activated in cells treated with AA. In addition, pharmacological inhibition of ERK1/2 and p38 as well as suppression of ROS generation with N-acetyl-L-cysteine resulted in the partial relief of cells from G2/M checkpoint and a decline of apoptosis level. Cell cycle arrest may be a mechanism for DNA repair, cell survival and reprogramming of epithelial cells to the fibroblast type. An apoptosis of renal epithelial cells at higher AA dose might be necessary to provide space for newly reprogrammed fibrotic cells. PMID:24792323

  7. Oscillation of APC/C activity during cell cycle arrest promotes centrosome amplification

    PubMed Central

    Prosser, Suzanna L.; Samant, Mugdha D.; Baxter, Joanne E.; Morrison, Ciaran G.; Fry, Andrew M.

    2014-01-01

    Centrosome duplication is licensed by the disengagement, or ‘uncoupling’, of centrioles during late mitosis. However, arrest of cells in G2 can trigger premature centriole disengagement. Here, we show that premature disengagement results from untimely activation of the APC/C leading to securin degradation and release of active separase. APC/C activation during G2 arrest is dependent on Plk1-mediated degradation of the APC/C inhibitor, Emi1, but Plk1 also has a second APC/C-independent role in promoting disengagement. Importantly, APC/C and Plk1 activity also stimulate centriole disengagement in response to hydroxyurea or DNA damage-induced cell cycle arrest and this leads to centrosome amplification. However, the re-duplication of disengaged centrioles is dependent on Cdk2 activity and Cdk2 activation coincides with a subsequent inactivation of the APC/C and re-accumulation of cyclin A. Release from these arrests leads to mitotic entry but, due to the presence of disengaged and/or amplified centrosomes, formation of abnormal mitotic spindles that lead to chromosome missegregation. Thus, oscillation of APC/C activity during cell cycle arrest promotes both centrosome amplification and genome instability. PMID:22956538

  8. Cell Cycle-Dependent Mechanisms Underlie Vincristine-Induced Death of Primary Acute Lymphoblastic Leukemia Cells.

    PubMed

    Kothari, Anisha; Hittelman, Walter N; Chambers, Timothy C

    2016-06-15

    Microtubule-targeting agents (MTA), such as the taxanes and vinca alkaloids, are used to treat a variety of cancers due to their ability to perturb microtubule dynamics. In cell culture, MTAs exert their anticancer effects primarily by causing mitotic arrest and cell death. However, accumulating indirect evidence suggests that MTAs may exert their cytotoxicity in human tumors by interfering with interphase microtubules. In this study, we sought to develop and characterize an experimental system in which to test the hypothesis that MTAs induce cell death during interphase. Primary adult acute lymphoblastic leukemia (ALL) cells treated with vincristine only weakly exhibited colocalization between mitotic and apoptotic markers and major characteristics of mitotic death, such as an increase in cells with 4N DNA content before the appearance of cells with <2N DNA content, suggesting a mixed response. Therefore, we separated ALL cells into distinct phases of the cell cycle by centrifugal elutriation, labeled cells with 5-ethynyl-2'-deoxyuridine (EdU), and then treated each population with vincristine. Cells isolated during G1 underwent cell death without evidence of EdU uptake, indicating that the cytotoxic effects of vincristine took place during G1 Conversely, cells isolated during S or G2-M phases underwent death following mitotic arrest. Thus, vincristine induces distinct death programs in primary ALL cells depending on cell-cycle phase, and cells in G1 are particularly susceptible to perturbation of interphase microtubules. Primary ALL cells may therefore provide a powerful model system in which to study the multimodal mechanisms underlying MTA-induced cell death. Cancer Res; 76(12); 3553-61. ©2016 AACR. PMID:27197148

  9. Hellebrigenin induces cell cycle arrest and apoptosis in human hepatocellular carcinoma HepG2 cells through inhibition of Akt.

    PubMed

    Deng, Li-Juan; Hu, Li-Ping; Peng, Qun-Long; Yang, Xiao-Lin; Bai, Liang-Liang; Yiu, Anita; Li, Yong; Tian, Hai-Yan; Ye, Wen-Cai; Zhang, Dong-Mei

    2014-08-01

    Hellebrigenin, one of bufadienolides belonging to cardioactive steroids, was found in skin secretions of toads and plants of Helleborus and Kalanchoe genera. In searching for natural constituents with anti-hepatoma activities, we found that hellebrigenin, isolated from traditional Chinese medicine Venenum Bufonis, potently reduced the viability and colony formation of human hepatocellular carcinoma cells HepG2, and went on to explore the underlying molecular mechanisms. Our results demonstrated that hellebrigenin triggered DNA damage through DNA double-stranded breaks and subsequently induced cell cycle G2/M arrest associated with up-regulation of p-ATM (Ser(1981)), p-Chk2 (Tyr(68)), p-CDK1 (Tyr(15)) and Cyclin B1, and down-regulation of p-CDC25C (Ser(216)). It was also found that hellebrigenin induced mitochondrial apoptosis, characterized by Bax translocation to mitochondria, disruption of mitochondrial membrane potential, release of cytochrome c into cytosol and sequential activation of caspases and PARP. In addition, Akt expression and phosphorylation were inhibited by hellebrigenin, whereas Akt silencing with siRNA significantly blocked cell cycle arrest but enhanced apoptosis induced by hellebrigenin. Activation of Akt by human insulin-like growth factor I (hIGF-I) could obviously attenuate hellebrigenin-induced cell death. In summary, our study is the first to report the efficacy of hellebrigenin against HepG2 and elucidated its molecular mechanisms including DNA damage, mitochondria collapse, cell cycle arrest and apoptosis, which will contribute to the development of hellebrigenin into a chemotherapeutic agent in the treatment of liver cancer. PMID:24954031

  10. Loss of p53-mediated cell-cycle arrest, senescence and apoptosis promotes genomic instability and premature aging

    PubMed Central

    Li, Tongyuan; Liu, Xiangyu; Jiang, Le; Manfredi, James; Zha, Shan; Gu, Wei

    2016-01-01

    Although p53-mediated cell cycle arrest, senescence and apoptosis are well accepted as major tumor suppression mechanisms, the loss of these functions does not directly lead to tumorigenesis, suggesting that the precise roles of these canonical activities of p53 need to be redefined. Here, we report that the cells derived from the mutant mice expressing p533KR, an acetylation-defective mutant that fails to induce cell-cycle arrest, senescence and apoptosis, exhibit high levels of aneuploidy upon DNA damage. Moreover, the embryonic lethality caused by the deficiency of XRCC4, a key DNA double strand break repair factor, can be fully rescued in the p533KR/3KR background. Notably, despite high levels of genomic instability, p533KR/3KRXRCC4−/− mice, unlike p53−/− XRCC4−/− mice, are not succumbed to pro-B-cell lymphomas. Nevertheless, p533KR/3KR XRCC4−/− mice display aging-like phenotypes including testicular atrophy, kyphosis, and premature death. Further analyses demonstrate that SLC7A11 is downregulated and that p53-mediated ferroptosis is significantly induced in spleens and testis of p533KR/3KRXRCC4−/− mice. These results demonstrate that the direct role of p53-mediated cell cycle arrest, senescence and apoptosis is to control genomic stability in vivo. Our study not only validates the importance of ferroptosis in p53-mediated tumor suppression in vivo but also reveals that the combination of genomic instability and activation of ferroptosis may promote aging-associated phenotypes. PMID:26943586

  11. Retama monosperma n-hexane extract induces cell cycle arrest and extrinsic pathway-dependent apoptosis in Jurkat cells

    PubMed Central

    2014-01-01

    cell cycle arrest and cell death that operates, at least partially, through the extrinsic apoptosis pathway. PMID:24460687

  12. Dux4 induces cell cycle arrest at G1 phase through upregulation of p21 expression

    SciTech Connect

    Xu, Hongliang; Wang, Zhaoxia; Jin, Suqin; Hao, Hongjun; Zheng, Lemin; Zhou, Boda; Zhang, Wei; Lv, He; Yuan, Yun

    2014-03-28

    Highlights: • Dux4 induced TE671 cell proliferation defect and G1 phase arrest. • Dux4 upregulated p21 expression without activating p53. • Silencing p21 rescued Dux4 mediated proliferation defect and cell cycle arrest. • Sp1 binding site was required for Dux4-induced p21 promoter activation. - Abstract: It has been implicated that Dux4 plays crucial roles in development of facioscapulohumeral dystrophy. But the underlying myopathic mechanisms and related down-stream events of this retrogene were far from clear. Here, we reported that overexpression of Dux4 in a cell model TE671 reduced cell proliferation rate, and increased G1 phase accumulation. We also determined the impact of Dux4 on p53/p21 signal pathway, which controls the checkpoint in cell cycle progression. Overexpression of Dux4 increased p21 mRNA and protein level, while expression of p53, phospho-p53 remained unchanged. Silencing p21 rescued Dux4 mediated proliferation defect and cell cycle arrest. Furthermore, we demonstrated that enhanced Dux4 expression increased p21 promoter activity and elevated expression of Sp1 transcription factor. Mutation of Sp1 binding site decreased dux4 induced p21 promoter activation. Chromatin immunoprecipitation (ChIP) assays confirmed the Dux4-induced binding of Sp1 to p21 promoter in vivo. These results suggest that Dux4 might induce proliferation inhibition and G1 phase arrest through upregulation of p21.

  13. Depletion of Aurora A leads to upregulation of FoxO1 to induce cell cycle arrest in hepatocellular carcinoma cells

    PubMed Central

    Lee, Sun-Young; Lee, Gong Rak; Woo, Dong-Hyuk; Park, Neung Hwa; Cha, Hee Jeong; Moon, Yong-Hwan; Han, In-Seob

    2013-01-01

    Aurora A kinase has drawn considerable attention as a therapeutic target for cancer therapy. However, the underlying molecular and cellular mechanisms of the anticancer effects of Aurora A kinase inhibition are still not fully understood. Herein, we show that depletion of Aurora A kinase by RNA interference (RNAi) in hepatocellular carcinoma (HCC) cells upregulated FoxO1 in a p53-dependent manner, which induces cell cycle arrest. Introduction of an RNAi-resistant Aurora A kinase into Aurora A-knockdown cells resulted in downregulation of FoxO1 expression and rescued proliferation. In addition, silencing of FoxO1 in Aurora A-knockdown cells allowed the cells to exit cytostatic arrest, which, in turn, led to massive cell death. Our results suggest that FoxO1 is responsible for growth arrest at the G2/M phase that is induced by Aurora A kinase inhibition. PMID:23255113

  14. Inhibiting the anaphase promoting complex/cyclosome induces a metaphase arrest and cell death in multiple myeloma cells

    PubMed Central

    Lub, Susanne; Maes, Anke; Maes, Ken; De Veirman, Kim; De Bruyne, Elke; Menu, Eline; Fostier, Karel; Kassambara, Alboukadel; Moreaux, Jérôme; Hose, Dirk; Leleu, Xavier; King, Randall W.

    2016-01-01

    The anaphase promoting complex/cyclosome (APC/C) is an ubiquitin ligase involved in cell cycle. During the metaphase-anaphase transition the APC/C is activated by Cdc20. The aim of this study is to elucidate the importance and therapeutic potential of APC/C and its co-activator Cdc20 in multiple myeloma (MM). Gene expression analysis revealed that Cdc20 was expressed at higher levels in gene expression-based high-risk MM patients. Moreover, high Cdc20 expression correlated with poor prognosis. Treatment of human myeloma cell lines with proTAME, an APC/C inhibitor, resulted in an accumulation of APC/CCdc20 substrate cyclin B1 and an accumulation of cells in metaphase. Moreover we observed a significant dose-dependent decrease in viability and increase in apoptosis in MM cells upon proTAME treatment. The induction of apoptosis was accompanied with caspase 3, 8, 9 and PARP cleavage. A similar metaphase arrest and induction of apoptosis were obtained with specific knockdown of Cdc20. In addition, we demonstrated the accumulation of Bim was partially responsible for the observed cell death. Combining proTAME with another APC/C inhibitor apcin or the alkylating agent melphalan resulted in enhanced anti-MM activity. This study suggests that the APC/C and its co-activator Cdc20 could be a new and promising target especially in high-risk MM patients. PMID:26716651

  15. Triptolide Abrogates Growth of Colon Cancer and Induces Cell Cycle Arrest by Inhibiting Transcriptional Activation of E2F

    PubMed Central

    Chugh, Rohit; Skube, Steven J; Majumder, Kaustav; Banerjee, Sulagna; Sangwan, Veena; Li, Lihua; Dawra, Rajinder; Subramanian, Subbaya; Saluja, Ashok; Dudeja, Vikas

    2016-01-01

    Background Despite significant progress in diagnostics and therapeutics, over fifty thousand patients die from colorectal cancer annually. Hence there is urgent need for new lines of treatment. Triptolide, a natural compound isolated from the Chinese herb Tripterygium wilfordii, is effective against multiple cancers. We have synthesized a water soluble analog of triptolide, named Minnelide, which is currently in phase I trial against pancreatic cancer. The aims of the current study were to evaluate whether triptolide/Minnelide is effective against colorectal cancer and to elucidate the mechanism by which triptolide induces cell death in colorectal cancer. Methods Efficacy of Minnelide was evaluated in subcutaneous xenograft and liver metastasis model of colorectal cancer. For mechanistic studies colon cancer cell lines HCT116 and HT29 were treated with triptolide and the effect on viability, caspase activation, annexin positivity, lactate dehydrogenase(LDH) release and cell cycle progression was evaluated. Effect of triptolide on E2F transcriptional activity, mRNA levels of E2F dependent genes, E2F1-Rb binding and proteins levels of regulator of G1-S transition was also measured. DNA binding of E2F1 was evaluated by chromatin immunoprecipitation assay. Results Triptolide decreased colon cancer cell viability in a dose- and time-dependent fashion. Minnelide markedly inhibited the growth of colon cancer in the xenograft and liver metastasis model of colon cancer and more than doubles the median survival of animals with liver metastases from colon cancer. Mechanistically we demonstrate that at low concentrations, triptolide induces apoptotic cell death but at higher concentrations it induces cell cycle arrest. Our data suggest that triptolide is able to induce G1 cell cycle arrest by inhibiting transcriptional activation of E2F1. Our data also show that triptolide downregulates E2F activity by potentially modulating events downstream of DNA binding. Conclusion

  16. Triptolide abrogates growth of colon cancer and induces cell cycle arrest by inhibiting transcriptional activation of E2F.

    PubMed

    Oliveira, Amanda R; Beyer, Georg; Chugh, Rohit; Skube, Steven J; Majumder, Kaustav; Banerjee, Sulagna; Sangwan, Veena; Li, Lihua; Dawra, Rajinder K; Subramanian, Subbaya; Saluja, Ashok K; Dudeja, Vikas

    2015-06-01

    Despite significant progress in diagnostics and therapeutics, over 50 thousand patients die from colorectal cancer annually. Hence, there is urgent need for new lines of treatment. Triptolide, a natural compound isolated from the Chinese herb Tripterygium wilfordii, is effective against multiple cancers. We have synthesized a water soluble analog of triptolide, named Minnelide, which is currently in phase I trial against pancreatic cancer. The aims of the current study were to evaluate whether triptolide/Minnelide is effective against colorectal cancer and to elucidate the mechanism by which triptolide induces cell death in colorectal cancer. Efficacy of Minnelide was evaluated in subcutaneous xenograft and liver metastasis model of colorectal cancer. For mechanistic studies, colon cancer cell lines HCT116 and HT29 were treated with triptolide and the effect on viability, caspase activation, annexin positivity, lactate dehydrogenase release, and cell cycle progression was evaluated. Effect of triptolide on E2F transcriptional activity, mRNA levels of E2F-dependent genes, E2F1- retinoblastoma protein (Rb) binding, and proteins levels of regulator of G1-S transition was also measured. DNA binding of E2F1 was evaluated by chromatin immunoprecipitation assay. Triptolide decreased colon cancer cell viability in a dose- and time-dependent fashion. Minnelide markedly inhibited the growth of colon cancer in the xenograft and liver metastasis model of colon cancer and more than doubles the median survival of animals with liver metastases from colon cancer. Mechanistically, we demonstrate that at low concentrations triptolide induces apoptotic cell death but at higher concentrations it induces cell cycle arrest. Our data suggest that triptolide is able to induce G1 cell cycle arrest by inhibiting transcriptional activation of E2F1. Our data also show that triptolide downregulates E2F activity by potentially modulating events downstream of DNA binding. Therefore, we conclude

  17. Cell cycle age dependence for radiation-induced G/sub 2/ arrest: evidence for time-dependent repair

    SciTech Connect

    Rowley, R.

    1985-09-01

    Exponentially growing eucaryotic cells, irradiated in interphase, are delayed in progression to mitosis chiefly by arrest in G/sub 2/. The sensitivity of Chinese hamster ovary cells to G/sub 2/ arrest induction by X rays increases through the cell cycle, up to the X-ray transition point (TP) in G/sub 2/. This age response can be explained by cell cycle age-dependent changes in susceptibility of the target(s) for G/sub 2/ arrest and/or by changes in capability for postirradiation recovery from G/sub 2/ arrest damage. Discrimination between sensitivity changes and repair phenomena is possible only if the level of G/sub 2/ arrest-causing damage sustained by a cell at the time of irradiation and the level ultimately expressed as arrest can be determined. The ability of caffeine to ameliorate radiation-induced G/sub 2/ arrest, while inhibiting repair of G/sub 2/ arrest-causing damage makes such an analysis possible. In the presence of caffeine, progression of irradiated cells was relatively unperturbed, but on caffeine removal, G/sub 2/ arrest was expressed. The duration of G/sub 2/ arrest was independent of the length of the prior caffeine exposure. This finding indicates that the target for G/sub 2/ arrest induction is present throughout the cell cycle and that the level of G/sub 2/ arrest damage incurred is initially constant for all cell cycle phases. The data are consistent with the existence of a time-dependent recovery mechanism to explain the age dependence for radiation induction of G/sub 2/ arrest.

  18. Postnatal telomere dysfunction induces cardiomyocyte cell-cycle arrest through p21 activation.

    PubMed

    Aix, Esther; Gutiérrez-Gutiérrez, Óscar; Sánchez-Ferrer, Carlota; Aguado, Tania; Flores, Ignacio

    2016-06-01

    The molecular mechanisms that drive mammalian cardiomyocytes out of the cell cycle soon after birth remain largely unknown. Here, we identify telomere dysfunction as a critical physiological signal for cardiomyocyte cell-cycle arrest. We show that telomerase activity and cardiomyocyte telomere length decrease sharply in wild-type mouse hearts after birth, resulting in cardiomyocytes with dysfunctional telomeres and anaphase bridges and positive for the cell-cycle arrest protein p21. We further show that premature telomere dysfunction pushes cardiomyocytes out of the cell cycle. Cardiomyocytes from telomerase-deficient mice with dysfunctional telomeres (G3 Terc(-/-)) show precocious development of anaphase-bridge formation, p21 up-regulation, and binucleation. In line with these findings, the cardiomyocyte proliferative response after cardiac injury was lost in G3 Terc(-/-) newborns but rescued in G3 Terc(-/-)/p21(-/-) mice. These results reveal telomere dysfunction as a crucial signal for cardiomyocyte cell-cycle arrest after birth and suggest interventions to augment the regeneration capacity of mammalian hearts. PMID:27241915

  19. Postmortem serum protein growth arrest-specific 6 levels in sepsis-related deaths.

    PubMed

    Palmiere, Cristian; Augsburger, Marc

    2015-09-01

    Growth arrest-specific 6 (Gas6) is widely expressed in leukocytes, platelets, endothelial cells, and monocytes. It regulates various processes including granulocyte adhesion to the endothelium, cell migration, thrombus stabilization, and cytokine release. In humans, increased plasma Gas6 levels have been described in patients with sepsis and septic shock. In this study, Gas6 concentrations were measured in postmortem serum from femoral blood in a series of sepsis-related fatalities and control cases. The aims were twofold: first, to determine whether Gas6 can be reliably determined in postmortem serum; and second, to assess its diagnostic potential in identifying sepsis-related deaths. Two study groups were prospectively formed, a sepsis-related fatalities group (24 cases) and a control group (24 cases) including cases of deep vein thrombosis and fatal pulmonary embolism, cases of systemic inflammatory response syndrome in severe trauma, cases of end-stage renal failure, and cases of hanging (non-septic, non-SIRS, non-end stage renal failure cases). The preliminary results of this study seem to indicate that Gas6 can be effectively measured in postmortem serum. However, Gas6 levels in sepsis-related fatalities do not appear to be clearly distinguishable from concentrations in pulmonary embolism, severe trauma, and end-stage renal failure cases. These findings tend to support previous reports that indicated that Gas6 behaves as an acute phase reactant and can be considered a general marker of inflammation rather than a specific biomarker of sepsis. PMID:26233610

  20. Somatostatin receptor-1 induces cell cycle arrest and inhibits tumor growth in pancreatic cancer.

    PubMed

    Li, Min; Wang, Xiaochi; Li, Wei; Li, Fei; Yang, Hui; Wang, Hao; Brunicardi, F Charles; Chen, Changyi; Yao, Qizhi; Fisher, William E

    2008-11-01

    Functional somatostatin receptors (SSTR) are lost in human pancreatic cancer. Transfection of SSTR-1 inhibited pancreatic cancer cell proliferation in vitro. We hypothesize that stable transfection of SSTR-1 may inhibit pancreatic cancer growth in vivo possibly through cell cycle arrest. In this study, we examined the expression of SSTR-1 mRNA in human pancreatic cancer tissue specimens, and investigated the effect of SSTR-1 overexpression on cell proliferation, cell cycle, and tumor growth in a subcutaneous nude mouse model. We found that SSTR-1 mRNA was downregulated in the majority of pancreatic cancer tissue specimens. Transfection of SSTR-1 caused cell cycle arrest at the G(0)/G(1) growth phase, with a corresponding decline of cells in the S (mitotic) phase. The overexpression of SSTR-1 significantly inhibited subcutaneous tumor size by 71% and 43% (n = 5, P < 0.05, Student's t-test), and inhibited tumor weight by 69% and 47% (n = 5, P < 0.05, Student's t-test), in Panc-SSTR-1 and MIA-SSTR-1 groups, respectively, indicating the potent inhibitory effect of SSTR-1 on pancreatic cancer growth. Our data demonstrate that overexpression of SSTR-1 significantly inhibits pancreatic cancer growth possibly through cell cycle arrest. This study suggests that gene therapy with SSTR-1 may be a potential adjuvant treatment for pancreatic cancer. PMID:18823376

  1. Somatostatin Receptor-1 Induces Cell Cycle Arrest and Inhibits Tumor Growth in Pancreatic Cancer

    PubMed Central

    Li, Min; Wang, Xiaochi; Li, Wei; Li, Fei; Yang, Hui; Wang, Hao; Brunicardi, F. Charles; Chen, Changyi; Yao, Qizhi; Fisher, William E.

    2010-01-01

    Functional somatostatin receptors (SSTRs) are lost in human pancreatic cancer. Transfection of SSTR-1 inhibited pancreatic cancer cell proliferation in vitro. We hypothesize that stable transfection of SSTR-1 may inhibit pancreatic cancer growth in vivo possibly through cell cycle arrest. In this study, we examined the expression of SSTR-1 mRNA in human pancreatic cancer tissue specimens, and investigated the effect of SSTR-1 overexpression on cell proliferation, cell cycle, and tumor growth in in a subcutaneous nude mouse model. We found that SSTR-1 mRNA was downregulated in the majority of pancreatic cancer tissue specimens. Transfection of SSTR-1 caused cell cycle arrest at the G0/G1 growth phase, with a corresponding decline of cells in the S (mitotic) phase. The overexpression of SSTR-1 significantly inhibited subcutaneous tumor size by 71% and 43% (n=5, p<0.05, t-test), and inhibited tumor weight by 69% and 47%, (n=5, p<0.05, t-test), in Panc-SSTR-1 and MIA-SSTR-1 groups, respectively, indicating the potent inhibitory effect of SSTR-1 on pancreatic cancer growth. Our data demonstrate that overexpression of SSTR-1 significantly inhibits pancreatic cancer growth possibly through cell cycle arrest. This study suggests that gene therapy with SSTR-1 may be a potential adjuvant treatment for pancreatic cancer. PMID:18823376

  2. HIV protease inhibitor nelfinavir inhibits growth of human melanoma cells by induction of cell cycle arrest.

    PubMed

    Jiang, Wei; Mikochik, Peter J; Ra, Jin H; Lei, Hanqin; Flaherty, Keith T; Winkler, Jeffrey D; Spitz, Francis R

    2007-02-01

    HIV protease inhibitors (HIV PI) are a class of antiretroviral drugs that are designed to target the viral protease. Unexpectedly, this class of drugs is also reported to have antitumor activity. In this study, we have evaluated the in vitro activity of nelfinavir, a HIV PI, against human melanoma cells. Nelfinavir inhibits the growth of melanoma cell lines at low micromolar concentrations that are clinically attainable. Nelfinavir promotes apoptosis and arrests cell cycle at G(1) phase. Cell cycle arrest is attributed to inhibition of cyclin-dependent kinase 2 (CDK2) and concomitant dephosphorylation of retinoblastoma tumor suppressor. We further show that nelfinavir inhibits CDK2 through proteasome-dependent degradation of Cdc25A phosphatase. Our results suggest that nelfinavir is a promising candidate chemotherapeutic agent for advanced melanoma, for which novel and effective therapies are urgently needed. PMID:17283158

  3. Dietary NiCl2 causes G2/M cell cycle arrest in the broiler's kidney

    PubMed Central

    Guo, Hongrui; Cui, Hengmin; Peng, Xi; Fang, Jing; Zuo, Zhicai; Deng, Junliang; Wang, Xun; Wu, Bangyuan; Chen, Kejie; Deng, Jie

    2015-01-01

    Here we showed that dietary NiCl2 in excess of 300 mg/kg caused the G2/M cell cycle arrest and the reduction of cell proportion at S phase. The G2/M cell cycle arrest was accompanied by up-regulation of phosphorylated ataxia telangiectasia mutated (p-ATM), p53, p-Chk1, p-Chk2, p21 protein expression and ATM, p53, p21, Chk1, Chk2 mRNA expression, and down-regulation of p-cdc25C, cdc2, cyclinB and proliferating cell nuclear antigen (PCNA) protein expression and the cdc25, cdc2, cyclinB, PCNA mRNA expression. PMID:26440151

  4. Synthesis, characterization, cytotoxicity, a poptosis and cell cycle arrest of dibenzoxanthenes derivatives

    NASA Astrophysics Data System (ADS)

    Wang, Xiu-Zhen; Yao, Jun-Hua; Jiang, Guang-Bin; Wang, Ji; Huang, Hong-Liang; Liu, Yun-Jun

    2014-12-01

    Two new dibenzoxanthenes compounds 1 and 2 have been synthesized and characterized by analytical and spectral methods. The crystal structure of compound 2 informs that the five rings of compound are almost planar. The DNA binding properties of two compounds were studied by absorption titration, viscosity measurement and luminescence. These results indicate that two compounds interact with calf thymus DNA through intercalative mode. Agarose gel electrophoresis experiment shows that PBR 322 DNA can be induced to cleave by two compounds under photoactivated condition. Compound 1 exhibits higher cytotoxicity than compound 2 toward MG-63, BEL-7402 and A549 cells. The apoptosis and cellular uptake of MG-63 cells were studied by fluorescence microscopy. Two compounds can also enhance the level of reactive oxygen species (ROS) and decrease the mitochondrial membrane potential. Compound 1 induces cell cycle arrest in G2/M phase and compound 2 induces cell cycle arrest in G0/G1 phase in MG-63.

  5. Cell cycle arrest and apoptosis, two alternative mechanisms for PMKT2 killer activity.

    PubMed

    Santos, Antonio; Alonso, Alejandro; Belda, Ignacio; Marquina, Domingo

    2013-01-01

    Pichia membranifaciens CYC 1086 secretes a unique 30kDa killer toxin (PMKT2) that inhibits a variety of spoilage yeasts and fungi of agronomical interest. The cytocidal effect of PMKT2 on Saccharomyces cerevisiae cells was studied. Metabolic events associated with the loss of S. cerevisiae viability caused by PMKT2 were qualitatively identical to those reported for K28 killer toxin activity, but different to those reported for PMKT. At higher doses, none of the cellular events accounting for the action of PMKT, the killer toxin secreted by P. membranifaciens CYC 1106, was observed for PMKT2. Potassium leakage, sodium influx and the decrease of intracellular pH were not among the primary effects of PMKT2. We report here that this protein is unable to form ion-permeable channels in liposome membranes, suggesting that channel formation is not the mechanism of cytotoxic action of PMKT2. Nevertheless, flow cytometry studies have revealed a cell cycle arrest at an early S-phase with an immature bud and pre-replicated 1n DNA content. By testing the sensitivity of cells arrested at different stages in the cell cycle, we hoped to identify the execution point for lethality more precisely. Cells arrested at the G1-phase by α-factor or arrested at G2-phase by the spindle poison methyl benzimidazol-2-yl-carbamate (MBC) were protected against the toxin. Cells released from the arrest in both cases were killed by PMKT2 at a similar rate. Nevertheless, cells released from MBC-arrest were able to grow for a short time, and then viability dropped rapidly. These findings suggest that cells released from G2-phase are initially able to divide, but die in the presence of PMKT2 after initiating the S-phase in a new cycle, adopting a terminal phenotype within that cycle. By contrast, low doses of PMKT and PMKT2 were able to generate the same cellular response. The evidence presented here shows that treating yeast with low doses of PMKT2 leads to the typical membranous, cytoplasmic

  6. INHIBITORY EFFECT OF TETRAMETHYLPYRAZINE ON HEPATOCELLULAR CARCINOMA: POSSIBLE ROLE OF APOPTOSIS AND CELL CYCLE ARREST.

    PubMed

    Cao, J; Miao, Q; Zhang, J; Miao, S; Bi, L; Zhang, S; Yang, Q; Zhou, X; Zhang, M; Xie, Y; Wang, S

    2015-01-01

    Hepatocellular carcinoma (HCC) is the fifth most common cancer. An important approach to control HCC is chemoprevention. This study aims at investigating the antitumor effect of Tetramethylpyrazine (TMP). Rats were injected with N-Nitrosodiethylamine (DEN) to establish HCC. Tumor development was observed. Liver function was evaluated. Apoptosis and cell cycle arrest-related makers and signaling cascades were determined by Western blot, RT-PCR and flow cytometric analysis. The administration of TMP could significantly inhibit tumor development in DEN-induced HCC rats, shown by reduced incidence of tumor, decreased number of tumor nodules and reduced maximal size of tumor. DEN-induced increase of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase and alkaline phosphatase activities were significantly inhibited by TMP. TMP exhibited inhibitory effect on HCC through induction of apoptosis and cell cycle arrest in rats. TMP induced apoptosis through increasing Bax, decreasing Bcl-2, increasing the release of cytochrome c, and activating caspase, which consisted of the mitochondrial apoptotic pathway. TMP induced G2/M cell cycle arrest through down-regulation of cyclin B1/cdc2. In addition, inhibition of Akt and ERK signaling and the antioxidant activities of TMP may also contribute to its antitumor effect. These data provide new insight into the mechanisms underlying the antitumor effect of TMP. PMID:26122217

  7. Oridonin inhibits tumor growth in glioma by inducing cell cycle arrest and apoptosis.

    PubMed

    Zhang, X-H; Liu, Y-X; Jia, M; Han, J-S; Zhao, M; Ji, S-P; Li, A-M

    2014-01-01

    Glioma is the most common malignant intracranial tumors. Despite newly developed therapies, these treatments mainly target oncogenic signals, and unfortunately, fail to provide enough survival benefit in both human patients and mouse xenograft models, especially the first-generation therapies. Oridonin is purified from the Chinese herb Rabdosia rubescens and considered to exert extensive anti-cancer effects on human tumorigenesis. In this study, we systemically investigated the role of Oridonin in tumor growth and the underlying mechanisms in human glioma. We found that Oridonin inhibited cell proliferations in a dose- and time-dependent manner in both glioma U87 and U251 cells. Moreover, these anti-cancer effects were also confirmed in a mouse model bearing glioma. Furthermore, cell cycle arrest in S phase was observed in Oridonin-mediated growth inhibition by flow cytometry. Cell cycle arrest in S phase led to eventual cell apoptosis, as revealed by Hoechst 33342 staining and annexin V/PI double-staining. The cell apoptosis might be accomplished through a mitochondrial manner. In all, we were the first to our knowledge to report that Oridonin could exert anti-cancer effects on tumor growth in human glioma by inducing cell cycle arrest and eventual cell apoptosis. The identification of Oridonin as a critical mediator of glioma growth may potentiate Oridonin as a novel therapeutic strategies in glioma treatments. PMID:25553351

  8. Notch signaling indirectly promotes chondrocyte hypertrophy via regulation of BMP signaling and cell cycle arrest

    PubMed Central

    Shang, Xifu; Wang, Jinwu; Luo, Zhengliang; Wang, Yongjun; Morandi, Massimo M.; Marymont, John V.; Hilton, Matthew J.; Dong, Yufeng

    2016-01-01

    Cell cycle regulation is critical for chondrocyte differentiation and hypertrophy. Recently we identified the Notch signaling pathway as an important regulator of chondrocyte proliferation and differentiation during mouse cartilage development. To investigate the underlying mechanisms, we assessed the role for Notch signaling regulation of the cell cycle during chondrocyte differentiation. Real-time RT-PCR data showed that over-expression of the Notch Intracellular Domain (NICD) significantly induced the expression of p57, a cell cycle inhibitor, in chondrocytes. Flow cytometric analyses further confirmed that over-expression of NICD in chondrocytes enhances the G0/G1 cell cycle transition and cell cycle arrest. In contrast, treatment of chondrocytes with the Notch inhibitor, DAPT, decreased both endogenous and BMP2-induced SMAD 1/5/8 phosphorylation and knockdown of SMAD 1/5/8 impaired NICD-induced chondrocyte differentiation and p57 expression. Co-immunoprecipitation using p-SMAD 1/5/8 and NICD antibodies further showed a strong interaction of these proteins during chondrocyte maturation. Finally, RT-PCR and Western blot results revealed a significant reduction in the expression of the SMAD-related phosphatase, PPM1A, following NICD over-expression. Taken together, our results demonstrate that Notch signaling induces cell cycle arrest and thereby initiates chondrocyte hypertrophy via BMP/SMAD-mediated up-regulation of p57. PMID:27146698

  9. SPARC expression induces cell cycle arrest via STAT3 signaling pathway in medulloblastoma cells

    SciTech Connect

    Chetty, Chandramu; Dontula, Ranadheer; Gujrati, Meena; Lakka, Sajani S.

    2012-01-13

    Highlights: Black-Right-Pointing-Pointer Ectopic expression of SPARC impaired cell proliferation in medulloblastoma cells. Black-Right-Pointing-Pointer SPARC expression induces STAT3 mediated cell cycle arrest in medulloblastoma cells. Black-Right-Pointing-Pointer SPARC expression significantly inhibited pre-established tumor growth in nude-mice. -- Abstract: Dynamic cell interaction with ECM components has profound influence in cancer progression. SPARC is a component of the ECM, impairs the proliferation of different cell types and modulates tumor cell aggressive features. We previously reported that SPARC expression significantly impairs medulloblastoma tumor growth in vivo. In this study, we demonstrate that expression of SPARC inhibits medulloblastoma cell proliferation. MTT assay indicated a dose-dependent reduction in tumor cell proliferation in adenoviral mediated expression of SPARC full length cDNA (Ad-DsRed-SP) in D425 and UW228 cells. Flow cytometric analysis showed that Ad-DsRed-SP-infected cells accumulate in the G2/M phase of cell cycle. Further, immunoblot and immunoprecipitation analyses revealed that SPARC induced G2/M cell cycle arrest was mediated through inhibition of the Cyclin-B-regulated signaling pathway involving p21 and Cdc2 expression. Additionally, expression of SPARC decreased STAT3 phosphorylation at Tyr-705; constitutively active STAT3 expression reversed SPARC induced G2/M arrest. Ad-DsRed-SP significantly inhibited the pre-established orthotopic tumor growth and tumor volume in nude-mice. Immunohistochemical analysis of tumor sections from mice treated with Ad-DsRed-SP showed decreased immunoreactivity for pSTAT3 and increased immunoreactivity for p21 compared to tumor section from mice treated with mock and Ad-DsRed. Taken together our studies further reveal that STAT3 plays a key role in SPARC induced G2/M arrest in medulloblastoma cells. These new findings provide a molecular basis for the mechanistic understanding of the

  10. Novel mechanism of harmaline on inducing G2/M cell cycle arrest and apoptosis by up-regulating Fas/FasL in SGC-7901 cells.

    PubMed

    Wang, Yihai; Wang, Chunhua; Jiang, Chenguang; Zeng, Hong; He, Xiangjiu

    2015-01-01

    Harmaline (HAR), a natural occurrence β-carboline alkaloid, was isolated from the seeds of Peganum harmala and exhibited potent antitumor effect. In this study, the anti-gastric tumor effects of HAR were firstly investigated in vitro and in vivo. The results strongly showed that HAR could inhibit tumor cell proliferation and induce G2/M cell cycle arrest accompanied by an increase in apoptotic cell death in SGC-7901 cancer cells. HAR could up-regulate the expressions of cell cycle-related proteins of p-Cdc2, p21, p-p53, Cyclin B and down-regulate the expression of p-Cdc25C. In addition, HAR could up-regulate the expressions of Fas/FasL, activated Caspase-8 and Caspase-3. Moreover, blocking Fas/FasL signaling could markedly inhibit the apoptosis caused by HAR, suggesting that Fas/FasL mediated pathways were involved in HAR-induced apoptosis. Interestingly, HAR could also exert on antitumor activity with a dose of 15 mg/kg/day in vivo, which was also related with cell cycle arrest. These new findings provided a framework for further exploration of HAR which possess the potential antitumor activity by inducing cell cycle arrest and apoptosis. PMID:26678950

  11. Novel mechanism of harmaline on inducing G2/M cell cycle arrest and apoptosis by up-regulating Fas/FasL in SGC-7901 cells

    PubMed Central

    Wang, Yihai; Wang, Chunhua; Jiang, Chenguang; Zeng, Hong; He, Xiangjiu

    2015-01-01

    Harmaline (HAR), a natural occurrence β-carboline alkaloid, was isolated from the seeds of Peganum harmala and exhibited potent antitumor effect. In this study, the anti-gastric tumor effects of HAR were firstly investigated in vitro and in vivo. The results strongly showed that HAR could inhibit tumor cell proliferation and induce G2/M cell cycle arrest accompanied by an increase in apoptotic cell death in SGC-7901 cancer cells. HAR could up-regulate the expressions of cell cycle-related proteins of p-Cdc2, p21, p-p53, Cyclin B and down-regulate the expression of p-Cdc25C. In addition, HAR could up-regulate the expressions of Fas/FasL, activated Caspase-8 and Caspase-3. Moreover, blocking Fas/FasL signaling could markedly inhibit the apoptosis caused by HAR, suggesting that Fas/FasL mediated pathways were involved in HAR-induced apoptosis. Interestingly, HAR could also exert on antitumor activity with a dose of 15 mg/kg/day in vivo, which was also related with cell cycle arrest. These new findings provided a framework for further exploration of HAR which possess the potential antitumor activity by inducing cell cycle arrest and apoptosis. PMID:26678950

  12. Fungal Ku prevents permanent cell cycle arrest by suppressing DNA damage signaling at telomeres

    PubMed Central

    de Sena-Tomás, Carmen; Yu, Eun Young; Calzada, Arturo; Holloman, William K.; Lue, Neal F.; Pérez-Martín, José

    2015-01-01

    The Ku heterodimer serves in the initial step in repairing DNA double-strand breaks by the non-homologous end-joining pathway. Besides this key function, Ku also plays a role in other cellular processes including telomere maintenance. Inactivation of Ku can lead to DNA repair defects and telomere aberrations. In model organisms where Ku has been studied, inactivation can lead to DNA repair defects and telomere aberrations. In general Ku deficient mutants are viable, but a notable exception to this is human where Ku has been found to be essential. Here we report that similar to the situation in human Ku is required for cell proliferation in the fungus Ustilago maydis. Using conditional strains for Ku expression, we found that cells arrest permanently in G2 phase when Ku expression is turned off. Arrest results from cell cycle checkpoint activation due to persistent signaling via the DNA damage response (DDR). Our results point to the telomeres as the most likely source of the DNA damage signal. Inactivation of the DDR makes the Ku complex dispensable for proliferation in this organism. Our findings suggest that in U. maydis, unprotected telomeres arising from Ku depletion are the source of the signal that activates the DDR leading to cell cycle arrest. PMID:25653166

  13. Fungal Ku prevents permanent cell cycle arrest by suppressing DNA damage signaling at telomeres.

    PubMed

    de Sena-Tomás, Carmen; Yu, Eun Young; Calzada, Arturo; Holloman, William K; Lue, Neal F; Pérez-Martín, José

    2015-02-27

    The Ku heterodimer serves in the initial step in repairing DNA double-strand breaks by the non-homologous end-joining pathway. Besides this key function, Ku also plays a role in other cellular processes including telomere maintenance. Inactivation of Ku can lead to DNA repair defects and telomere aberrations. In model organisms where Ku has been studied, inactivation can lead to DNA repair defects and telomere aberrations. In general Ku deficient mutants are viable, but a notable exception to this is human where Ku has been found to be essential. Here we report that similar to the situation in human Ku is required for cell proliferation in the fungus Ustilago maydis. Using conditional strains for Ku expression, we found that cells arrest permanently in G2 phase when Ku expression is turned off. Arrest results from cell cycle checkpoint activation due to persistent signaling via the DNA damage response (DDR). Our results point to the telomeres as the most likely source of the DNA damage signal. Inactivation of the DDR makes the Ku complex dispensable for proliferation in this organism. Our findings suggest that in U. maydis, unprotected telomeres arising from Ku depletion are the source of the signal that activates the DDR leading to cell cycle arrest. PMID:25653166

  14. Induction of apoptosis and cell-cycle arrest in human colon cancer cells by meclizine.

    PubMed

    Lin, Jiunn-Chang; Ho, Yuan-Soon; Lee, Jie-Jen; Liu, Chien-Liang; Yang, Tsen-Long; Wu, Chih-Hsiung

    2007-06-01

    Meclizine (MEC), a histamine H1 antagonist, is used for the treatment of motion sickness and vertigo. In this study, we demonstrate that MEC dose-dependently induced apoptosis in human colon cancer cell lines (COLO 205 and HT 29 cells). Results of a DNA ladder assay revealed that DNA ladders appeared with MEC treatment in COLO 205 cells at dosage of >50 microM. In addition, the total cell number decreased dose-dependently after treatment with MEC in COLO 205 and HT 29 cells. Using flow cytometry, the percentage of COLO 205 cells arrested at G0/G1 phase increased dose-dependently. Analysis of changes in cell-cycle arrest-associated proteins with Western blotting showed that p53 and p21 were upregulated after treatment with MEC. The kinase activities of cyclin-dependent kinase 2 (CDK2) and CDK4 were suppressed in MEC-treated cells. As for apoptosis, MEC may induce upregulation of p53 and downregulation of Bcl-2, thus causing the release of cytochrome C from mitochondria and the translocation of apoptosis-inducing factor (AIF) to the nucleus. This resulted in the activation of caspase 3, 8, and 9. Our results provide the molecular basis of MEC-induced apoptosis and cell-cycle arrest in human colon cancer cells. PMID:17222494

  15. Polydatin inhibits growth of lung cancer cells by inducing apoptosis and causing cell cycle arrest.

    PubMed

    Zhang, Yusong; Zhuang, Zhixiang; Meng, Qinghui; Jiao, Yang; Xu, Jiaying; Fan, Saijun

    2014-01-01

    Polydatin (PD), a small natural compound from Polygonum cuspidatum, has a number of biological functions. However, the anticancer activity of PD has been poorly investigated. In the present study, thiazolyl blue tetrazolium bromide assay was used to evaluate the inhibitory effect of PD on cell growth. Cell cycle distribution and apoptosis were investigated by flow cytometry. In addition, the expression of several proteins associated with apoptosis and cell cycle were analyzed by western blot analysis. The results demonstrated that PD significantly inhibits the proliferation of A549 and NCI-H1975 lung cancer cell lines and causes dose-dependent apoptosis. Cell cycle analysis revealed that PD induces S phase cell cycle arrest. Western blot analysis showed that the expression of Bcl-2 decreased as that of Bax increased, and the expression of cyclin D1 was also suppressed. The results suggest that PD has potential therapeutic applications in the treatment of lung cancer. PMID:24348867

  16. Cell cycle arrest induced by MPPa-PDT in MDA-MB-231 cells

    NASA Astrophysics Data System (ADS)

    Liang, Liming; Bi, Wenxiang; Tian, Yuanyuan

    2016-05-01

    Photodynamic therapy (PDT) is a medical treatment using a photosensitizing agent and light source to treat cancers. Pyropheophorbidea methyl ester (MPPa), a derivative of chlorophyll, is a novel potent photosensitizer. To learn more about this photosensitizer, we examined the cell cycle arrest in MDA-MB-231. Cell cycle and apoptosis were measured by flow cytometer. Checkpoints of the cell cycle were measured by western blot. In this study, we found that the expression of Cyclin D1 was obviously decreased, while the expression of Chk2 and P21 was increased after PDT treatment. This study showed that MPPa-PDT affected the checkpoints of the cell cycle and led the cells to apoptosis.

  17. Apigenin inhibits pancreatic cancer cell proliferation through G2/M cell cycle arrest

    PubMed Central

    Ujiki, Michael B; Ding, Xian-Zhong; Salabat, M Reza; Bentrem, David J; Golkar, Laleh; Milam, Ben; Talamonti, Mark S; Bell, Richard H; Iwamura, Takeshi; Adrian, Thomas E

    2006-01-01

    Background Many chemotherapeutic agents have been used to treat pancreatic cancer without success. Apigenin, a naturally occurring flavonoid, has been shown to inhibit growth in some cancer cell lines but has not been studied in pancreatic cancer. We hypothesized that apigenin would inhibit pancreatic cancer cell growth in vitro. Results Apigenin caused both time- and concentration-dependent inhibition of DNA synthesis and cell proliferation in four pancreatic cancer cell lines. Apigenin induced G2/M phase cell cycle arrest. Apigenin reduced levels of cyclin A, cyclin B, phosphorylated forms of cdc2 and cdc25, which are all proteins required for G2/M transition. Conclusion Apigenin inhibits growth of pancreatic cancer cells through suppression of cyclin B-associated cdc2 activity and G2/M arrest, and may be a valuable drug for the treatment or prevention of pancreatic cancer. PMID:17196098

  18. Respiratory syncytial virus matrix protein induces lung epithelial cell cycle arrest through a p53 dependent pathway.

    PubMed

    Bian, Tao; Gibbs, John D; Örvell, Claes; Imani, Farhad

    2012-01-01

    Respiratory syncytial virus (RSV) is the major cause of viral respiratory infections in children. Our previous study showed that the RSV infection induced lung epithelial cell cycle arrest, which enhanced virus replication. To address the mechanism of RSV-induced cell cycle arrest, we examined the contribution of RSV-matrix (RSV-M) protein. In this report, we show that in both the A549 cell line and primary human bronchial epithelial (PHBE) cells, transfection with RSV-M protein caused the cells to proliferate at a slower rate than in control cells. The cell cycle analysis showed that RSV-M protein induced G1 phase arrest in A549 cells, and G1 and G2/M phase arrest in PHBE cells. Interestingly, RSV-M expression induced p53 and p21 accumulation and decreased phosphorylation of retinoblastoma protein (Rb). Further, induction of cell cycle arrest by RSV-M was not observed in a p53-deficient epithelial cell line (H1299). However, cell cycle arrest was restored after transfection of p53 cDNA into H1299 cells. Taken together, these results indicate that RSV-M protein regulates lung epithelial cell cycle through a p53-dependent pathway, which enhances RSV replication. PMID:22662266

  19. Luteolin induces cell cycle arrest and apoptosis through extrinsic and intrinsic signaling pathways in MCF-7 breast cancer cells.

    PubMed

    Park, Su-Ho; Ham, Sunyoung; Kwon, Tae Ho; Kim, Man Sub; Lee, Dong Hun; Kang, Jeoung-Woo; Oh, Sei-Ryang; Yoon, Do-Young

    2014-01-01

    Luteolin is a common flavonoid that exists in medicinal herbs, fruits, and vegetables. Luteolin has biochemical functions including anti-allergy, anti-inflammation, and anti-cancer functions. However, its efficacy and precise mode of action against breast cancer are still under study. To elucidate whether luteolin exhibits an anticancer effect in breast cancer, MCF-7 breast cancer cells were incubated with luteolin, and apoptosis was assessed by observing nuclear morphological changes and by performing cell viability assay, cell cycle analysis, annexin V-FITC/PI double staining, western blotting, RT-PCR, and mitochondrial membrane potential measurements. Luteolin inhibited growth through perturbation of cell cycle progression at the sub-G1 and G1 phases in MCF-7 cells. Furthermore, luteolin enhanced the expression of death receptors, such as DR5, and activated caspase cascades. It enhanced the activities of caspase-8/-9/-3 in a dose-dependent manner, followed by inactivation of PARP. Activation of caspase-8 and caspase-9 induced caspase-3 activity, respectively, in apoptosis of extrinsic and intrinsic pathways. Luteolin also induced mitochondrial membrane potential collapse and cytochrome c release, and increased Bax expression by inhibiting expression of Bcl-2. Taken together, these results suggest that luteolin provokes cell cycle arrest and induces apoptosis by activating the extrinsic and intrinsic pathways. PMID:25272060

  20. JAZ mediates G1 cell cycle arrest by interacting with and inhibiting E2F1

    PubMed Central

    Yang, Mingli; Wu, Song; Jia, Jinghua

    2011-01-01

    We discovered and reported JAZ as a unique dsRNA binding zinc finger protein that functions as a direct, positive regulator of p53 transcriptional activity to mediate G1 cell cycle arrest in a mechanism involving upregulation of the p53 target gene, p21. We now find that JAZ can also negatively regulate the cell cycle in a novel, p53-independent mechanism resulting from the direct interaction with E2F1, a key intermediate in regulating cell proliferation and tumor suppression. JAZ associates with E2F1's central DNA binding/dimerization region and its C-terminal transactivation domain. Functionally, JAZ represses E2F1 transcriptional activity in association with repression of cyclin A expression and inhibition of G1/S transition. This mechanism involves JAZ-mediated inhibition of E2F1's specific DNA binding activity. JAZ directly binds E2F1 in vitro in a dsRNA-independent manner, and JAZ's dsRNA binding ZF domains, which are necessary for localizing JAZ to the nucleus, are required for repression of transcriptional activity in vivo. Importantly for specificity, siRNA-mediated “knockdown” of endogenous JAZ increases E2F transcriptional activity and releases cells from G1 arrest, indicating a necessary role for JAZ in this transition. Although JAZ can directly inhibit E2F1 activity independently of p53, if functional p53 is expressed, JAZ may exert a more potent inhibition of cell cycle following growth factor withdrawal. Therefore, JAZ plays a dual role in cell cycle regulation by both repressing E2F1 transcriptional activity and activating p53 to facilitate efficient growth arrest in response to cellular stress, which may potentially be exploited therapeutically for tumor growth inhibition. PMID:21715977

  1. A C21-Steroidal Glycoside Isolated from the Roots of Cynanchum auriculatum Induces Cell Cycle Arrest and Apoptosis in Human Gastric Cancer SGC-7901 Cells

    PubMed Central

    Wang, Yi-Qi; Zhang, Shui-Juan; Lu, Hong; Yang, Bo; Ye, Liang-Fei; Zhang, Ru-Song

    2013-01-01

    Caudatin 3-O-β-D-cymaropyranosyl-(1 → 4)-β-D-oleandropyranosyl-(1 → 4)-β-D-cymaropyranosyl-(1 → 4)-β-D-cymaropyranoside (CGII) is one of the C21-steroidal glycosides isolated from the roots of Cynanchum auriculatum ROYLE ex WIGHT. This study aimed to determine the cell growth, cell proliferation, and apoptotic cell death of human gastric cancer cells after CGII treatment. MTT assay was used to determine cell growth; fluorescence-activated cell sorting analysis was used to evaluate cell cycle distribution and apoptotic cell death. Immunoblotting was applied for measuring the expression of proteins involved in the cell cycle progression. The activities of caspase-3, -8, and -9 were detected by colorimetric caspase activity assays. CGII inhibited cell growth of human gastric cancer SGC-7901 cells in a concentration- and time-dependent manner. Treatment of SGC-7901 cells with CGII resulted in G1 phase cell cycle arrest, accompanied with decreased expression of cyclin D1 and cyclin-dependent kinases 4 and 6. CGII induced cell apoptosis and activated caspase-3, caspase-8, and caspase-9. In contrast, pan-caspase inhibitor z-VAD-fmk partially abolished the CGII-induced growth inhibition of SGC-7901 cells. In conclusion, CGII inhibits cell growth of human gastric cancer cells by inducing G1 phase cell cycle arrest and caspase-dependent apoptosis cascades. PMID:24454488

  2. Trichosanthes kirilowii fruits inhibit non-small cell lung cancer cell growth through mitotic cell-cycle arrest.

    PubMed

    Ni, Lulu; Zhu, Xiaowen; Gong, Chenyuan; Luo, Yinbin; Wang, Lixin; Zhou, Wuxiong; Zhu, Shiguo; Li, Yan

    2015-01-01

    Lung cancer is the leading cause of cancer-related death worldwide. Non-small cell lung cancer (NSCLC) accounts for 80% of lung cancer cases and the reported overall 5-year survival rate is less than 5%. Natural medicines have attracted much attention due to their lower toxicity and fewer side effects. Trichosanthes kirilowii Maxim (TKM) fruits are commonly used in cancer treatment in combination with other Chinese medicinal herbs. However, little is known about their biological functions and mechanisms in NSCLC cells. In this study, we investigated the efficacy of TKM fruits in NSCLC cells using cell proliferation, invasion, migration, and anchorage independent assays and a Xenograft NSCLC tumor model, and explored the possible biological mechanism by flow cytometric analysis, cDNA microarray and real-time PCR. Results showed that TKM fruits significantly suppressed NSCLC cell proliferation, migration, invasion, tumorigenicity and tumor growth, and significantly extended the survival time of NSCLC-bearing mice. Flow cytometric analysis showed that TKM fruits significantly induced G2-M arrest, necrosis and apoptosis in NSCLC cells. cDNA microarray analysis revealed that TKM fruits regulated the differential expression of 544 genes, and the differential expression of selected genes was also confirmed. Gene ontology (GO) analysis showed that 18 of first 20 biological processes were involved in cell cycle and mitosis. These results indicate that TKM fruits have certain inhibitory effect on NSCLC cells through cell-cycle and mitosis arrest, and suggest that TKM fruits may be an important resource for developing new antitumor drugs, and a potent natural product for treating patients with NSCLC. PMID:25779643

  3. Ziyuglycoside II induces cell cycle arrest and apoptosis through activation of ROS/JNK pathway in human breast cancer cells.

    PubMed

    Zhu, Xue; Wang, Ke; Zhang, Kai; Zhu, Ling; Zhou, Fanfan

    2014-05-16

    Ziyuglycoside II, a triterpenoid saponin compound extracted from Sanguisorba officinalis L., has been reported to have a wide range of clinical applications including anti-cancer effect. In this study, the anti-proliferative effect of ziyuglycoside II in two classic human breast cancer cell lines, MCF-7 and MDA-MB-231, was extensively investigated. Our study indicated that ziyuglycoside II could effectively induce G2/M phase arrest and apoptosis in both cell lines. Cell cycle blocking was associated with the down-regulation of Cdc25C, Cdc2, cyclin A and cyclin B1 as well as the up-regulation of p21/WAF1, phospho-Cdc25C and phospho-Cdc2. Ziyuglycoside II treatment also induced reactive oxygen species (ROS) production and apoptosis by activating the extrinsic/Fas/FasL pathway as well as the intrinsic/mitochondrial pathway. More importantly, the c-Jun NH2-terminal kinase (JNK), a downstream target of ROS, was found to be a critical mediator of ziyuglycoside II-induced cell apoptosis. Further knockdown of JNK by siRNA could inhibit ziyuglycoside II-mediated apoptosis with attenuating the up-regulation of Bax and Fas/FasL as well as the down-regulation of Bcl-2. Taken together, the cell death of breast cancer cells in response to ziyuglycoside II was dependent upon cell cycle arrest and cell apoptosis via a ROS-dependent JNK activation pathway. Our findings may significantly contribute to the understanding of the anti-proliferative effect of ziyuglycoside II, in particular to breast carcinoma and provide novel insights into the potential application of such compound in breast cancer therapy. PMID:24680927

  4. Soaking RNAi in Bombyx mori BmN4-SID1 cells arrests cell cycle progression.

    PubMed

    Mon, Hiroaki; Li, Zhiqing; Kobayashi, Isao; Tomita, Shuichiro; Lee, JaeMan; Sezutsu, Hideki; Tamura, Toshiki; Kusakabe, Takahiro

    2013-01-01

    RNA interference (RNAi) is an evolutionarily conserved mechanism for sequence-specific gene silencing. Previously, the BmN4-SID1 cell expressing Caenorhabditis ele gans SID-1 was established, in which soaking RNAi could induce effective gene silencing. To establish its utility, 6 cell cycle progression related cDNAs, CDK1, MYC, MYB, RNRS, CDT1, and GEMININ, were isolated from the silkworm, Bombyx mori L. (Lepidoptera: Bombycidae), and their expressions were further silenced by soaking RNAi in the BmN4-SID1 cells. The cell cycle progression analysis using flow cytometer demonstrated that the small amount of double stranded RNA was enough to arrest cell cycle progression at the specific cell phases. These data suggest that RNAi in the BmN4-SID1 cells can be used as a powerful tool for loss-of-function analysis of B. mori genes. PMID:24773378

  5. Phytometabolite Dehydroleucodine Induces Cell Cycle Arrest, Apoptosis, and DNA Damage in Human Astrocytoma Cells through p73/p53 Regulation

    PubMed Central

    Bailon-Moscoso, Natalia; González-Arévalo, Gabriela; Velásquez-Rojas, Gabriela; Malagon, Omar; Vidari, Giovanni; Zentella-Dehesa, Alejandro; Ratovitski, Edward A.; Ostrosky-Wegman, Patricia

    2015-01-01

    Accumulating evidence supports the idea that secondary metabolites obtained from medicinal plants (phytometabolites) may be important contributors in the development of new chemotherapeutic agents to reduce the occurrence or recurrence of cancer. Our study focused on Dehydroleucodine (DhL), a sesquiterpene found in the provinces of Loja and Zamora-Chinchipe. In this study, we showed that DhL displayed cytostatic and cytotoxic activities on the human cerebral astrocytoma D384 cell line. With lactone isolated from Gynoxys verrucosa Wedd, a medicinal plant from Ecuador, we found that DhL induced cell death in D384 cells by triggering cell cycle arrest and inducing apoptosis and DNA damage. We further found that the cell death resulted in the increased expression of CDKN1A and BAX proteins. A marked induction of the levels of total TP73 and phosphorylated TP53, TP73, and γ-H2AX proteins was observed in D384 cells exposed to DhL, but no increase in total TP53 levels was detected. Overall these studies demonstrated the marked effect of DhL on the diminished survival of human astrocytoma cells through the induced expression of TP73 and phosphorylation of TP73 and TP53, suggesting their key roles in the tumor cell response to DhL treatment. PMID:26309132

  6. Cellular Effect of Curcumin and Citral Combination on Breast Cancer Cells: Induction of Apoptosis and Cell Cycle Arrest

    PubMed Central

    Thakkar, Vasudev R.; Patel, Jagdish S.

    2015-01-01

    Purpose The unmanageable side effects caused by current chemotherapy regimens to treat cancer are an unresolved problem. Although many phytonutrients are useful as chemoprevention without side effects, their effects are slower and smaller than conventional chemotherapy. In the present work, we examined the cumulative effect of two phytonutrients, curcumin and citral, on breast cancer cell lines and compared their effect with the known chemotherapy regimen of cyclophosphamide, methotrexate, and 5-fluorouracil. Methods Using cultured breast cancer and normal epithelial cells, the cytotoxic and apoptotic effect of curcumin and citral was evaluated in vitro. The synergistic effect of curcumin and citral was calculated by a combination index study using the method by Chou and Talalay. Cell death pathways and mechanisms were analyzed by measuring intracellular reactive oxygen species (ROS) and apoptotic protein levels. Results Curcumin and citral caused dose and time dependent cell death and showed a synergistic effect at effective concentration EC50 and above concentrations in breast cancer cells without disturbing normal breast epithelial cells. With combination curcumin and citral treatment, apoptosis induction and cell cycle arrest at G0/G1 phase in breast cancer cells were observed. Curcumin and citral generated ROS and activated p53 and poly (ADP-ribose) polymerase-1 mediated apoptotic pathways. Conclusion The results of this study suggest that curcumin and citral in combination may be a useful therapeutic intervention for breast cancer. PMID:26472972

  7. Anti-Colon Cancer Effects of 6-Shogaol Through G2/M Cell Cycle Arrest by p53/p21-cdc2/cdc25A Crosstalk.

    PubMed

    Qi, Lian-Wen; Zhang, Zhiyu; Zhang, Chun-Feng; Anderson, Samantha; Liu, Qun; Yuan, Chun-Su; Wang, Chong-Zhi

    2015-01-01

    Chemopreventive agents can be identified from botanicals. Recently, there has been strong support for the potential of 6-shogaol, a natural compound from dietary ginger (Zingiber officinale), in cancer chemoprevention. However, whether 6-shogaol inhibits the growth of colorectal tumors in vivo remains unknown, and the underlying anticancer mechanisms have not been well characterized. In this work, we observed that 6-shogaol (15 mg/kg) significantly inhibited colorectal tumor growth in a xenograft mouse model. We show that 6-shogaol inhibited HCT-116 and SW-480 cell proliferation with IC50 of 7.5 and 10 μM, respectively. Growth of HCT-116 cells was arrested at the G2/M phase of the cell cycle, primarily mediated by the up-regulation of p53, the CDK inhibitor p21(waf1/cip1) and GADD45α, and by the down-regulation of cdc2 and cdc25A. Using p53(-/-) and p53(+/+) HCT-116 cells, we confirmed that p53/p21 was the main pathway that contributed to the G2/M cell cycle arrest by 6-shogaol. 6-Shogaol induced apoptosis, mainly through the mitochondrial pathway, and the bcl-2 family might act as a key regulator. Our results demonstrated that 6-shogaol induces cancer cell death by inducing G2/M cell cycle arrest and apoptosis. 6-Shogaol could be an active natural product in colon cancer chemoprevention. PMID:26119958

  8. Vitisin A inhibits adipocyte differentiation through cell cycle arrest in 3T3-L1 cells

    SciTech Connect

    Kim, Soon-hee; Park, Hee-Sook; Lee, Myoung-su; Cho, Yong-Jin; Kim, Young-Sup; Hwang, Jin-Taek; Sung, Mi Jeong; Kim, Myung Sunny; Kwon, Dae Young

    2008-07-18

    Inhibition of adipocyte differentiation is one approach among the anti-obesity strategies. This study demonstrates that vitisin A, a resveratrol tetramer, inhibits adipocyte differentiation most effectively of 18 stilbenes tested. Fat accumulation and PPAR{gamma} expression were decreased by vitisin A in a dose-dependent manner. Vitisin A significantly inhibited preadipocyte proliferation and consequent differentiation within the first 2 days of treatment, indicating that the anti-adipogenic effect of vitisin A was derived from anti-proliferation. Based on cell cycle analysis, vitisin A blocked the cell cycle at the G1-S phase transition, causing cells to remain in the preadipocyte state. Vitisin A increased p21 expression, while the Rb phosphorylation level was reduced. Therefore, vitisin A seems to induce G1 arrest through p21- and consequent Rb-dependent suppression of transcription. On the other hand, ERK and Akt signaling pathways were not involved in the anti-mitotic regulation by vitisin A. Taken together, these results suggest that vitisin A inhibits adipocyte differentiation through preadipocyte cell cycle arrest.

  9. Severe hypoxia induces complete antifolate resistance in carcinoma cells due to cell cycle arrest

    PubMed Central

    Raz, S; Sheban, D; Gonen, N; Stark, M; Berman, B; Assaraf, Y G

    2014-01-01

    Antifolates have a crucial role in the treatment of various cancers by inhibiting key enzymes in purine and thymidylate biosynthesis. However, the frequent emergence of inherent and acquired antifolate resistance in solid tumors calls for the development of novel therapeutic strategies to overcome this chemoresistance. The core of solid tumors is highly hypoxic due to poor blood circulation, and this hypoxia is considered to be a major contributor to drug resistance. However, the cytotoxic activity of antifolates under hypoxia is poorly characterized. Here we show that under severe hypoxia, gene expression of ubiquitously expressed key enzymes and transporters in folate metabolism and nucleoside homeostasis is downregulated. We further demonstrate that carcinoma cells become completely refractory, even at sub-millimolar concentrations, to all hydrophilic and lipophilic antifolates tested. Moreover, tumor cells retained sensitivity to the proteasome inhibitor bortezomib and the topoisomerase II inhibitor doxorubicin, which are independent of cell cycle. We provide evidence that this antifolate resistance, associated with repression of folate metabolism, is a result of the inability of antifolates to induce DNA damage under hypoxia, and is attributable to a hypoxia-induced cell cycle arrest, rather than a general anti-apoptotic mechanism. Our findings suggest that solid tumors harboring a hypoxic core of cell cycle-arrested cells may display antifolate resistance while retaining sensitivity to the chemotherapeutics bortezomib and doxorubicin. This study bears important implications for the molecular basis underlying antifolate resistance under hypoxia and its rational overcoming in solid tumors. PMID:24556682

  10. SOX10 ablation arrests the cell cycle, induces senescence and suppresses melanomagenesis

    PubMed Central

    Cronin, Julia C.; Watkins-Chow, Dawn E.; Incao, Art; Hasskamp, Joanne H.; Schönewolf, Nicola; Aoude, Lauren G.; Hayward, Nicholas K.; Bastian, Boris C.; Dummer, Reinhard; Loftus, Stacie K.; Pavan, William J.

    2013-01-01

    The transcription factor SOX10 is essential for survival and proper differentiation of neural crest cell lineages, where it plays an important role in the generation and maintenance of melanocytes. SOX10 is also highly expressed in melanoma tumors, but a role in disease progression has not been established. Here we report that melanoma tumor cell lines require wild-type SOX10 expression for proliferation, and SOX10 haploinsufficiency reduces melanoma initiation in the metabotropic glutamate receptor 1 (Grm1Tg) transgenic mouse model. Stable SOX10 knockdown in human melanoma cells arrested cell growth, altered cellular morphology, and induced senescence. Melanoma cells with stable loss of SOX10 were arrested in the G1 phase of the cell cycle, with reduced expression in the melanocyte determining factor MITF, elevated expression of p21WAF1 and p27KIP2, hypophosphorylated RB and reduced levels of its binding partner E2F1. Since cell cycle dysregulation is a core event in neoplastic transformation, the role for SOX10 in maintaining cell cycle control in melanocytes suggests a rational new direction for targeted treatment or prevention of melanoma. PMID:23913827

  11. Metformin impairs growth of endometrial cancer cells via cell cycle arrest and concomitant autophagy and apoptosis

    PubMed Central

    2014-01-01

    Background Effective therapies for early endometrial cancer usually involve surgical excision and consequent infertility Therefore, new treatment approaches that preserve fertility should be developed. Metformin, a well-tolerated anti-diabetic drug, can inhibit cancer cell growth. However, the mechanism of metformin action is not well understood. Here we investigate the roles of autophagy and apoptosis in the anti-cancer effects of metformin on endometrial cancer cells. Methods Ishikawa endometrial cancer cells were treated with metformin. WST-8 assays, colony formation assays, flow cytometry, caspase luminescence measurement, immunofluorescence, and western blots were used to assess the effects of metformin on cell viability, proliferation, cell cycle progression, apoptosis, and autophagy. Results Metformin-treated cells exhibited significantly lower viability and proliferation and significantly more cell cycle arrest in G1 and G2/M than control cells. These cells also exhibited significantly more apoptosis via both intrinsic and extrinsic pathways. In addition, metformin treatment induced autophagy. Inhibition of autophagy, either by Beclin1 knockdown or by 3-methyladenine-mediated inhibition of caspase-3/7, suppressed the anti-proliferative effects of metformin on endometrial cancer cells. These findings indicate that the anti-proliferative effects and apoptosis caused by metformin are partially or completely dependent on autophagy. Conclusions We showed that metformin suppresses endometrial cancer cell growth via cell cycle arrest and concomitant autophagy and apoptosis. PMID:24966801

  12. Induction of cell cycle arrest in prostate cancer cells by the dietary compound isoliquiritigenin.

    PubMed

    Lee, Yeo Myeong; Lim, Do Young; Choi, Hyun Ju; Jung, Jae In; Chung, Won-Yoon; Park, Jung Han Yoon

    2009-02-01

    Isoliquiritigenin (ISL), a flavonoid chalcone that is present in licorice, shallot, and bean sprouts, is known to have antitumorigenic activities. The present study examined whether ISL alters prostate cancer cell cycle progression. DU145 human and MatLyLu (MLL) rat prostate cancer cells were cultured with various concentrations of ISL. In both DU145 and MLL cells treated with ISL, the percentage of cells in the G1 phase increased, and the incorporation of [(3)H]thymidine decreased. ISL decreased the protein levels of cyclin D1, cyclin E, and cyclin-dependent kinase (CDK) 4, whereas cyclin A and CDK2 expressions were unaltered in cells treated with ISL. The expression of the CDK inhibitor p27(KIP1) was increased in cells treated with 20 micromol/L ISL. In addition, treatment of cells with 20 micromol/L ISL for 24 hours led to G2/M cell cycle arrest. Cell division control (CDC) 2 protein levels remained unchanged. The protein levels of phospho-CDC2 (Tyr15) and cyclin B1 were increased, and the CDC25C level was decreased by ISL dose-dependently. We demonstrate that ISL promotes cell cycle arrest in DU145 and MLL cells, thereby providing insights into the mechanisms underlying its antitumorigenic activities. PMID:19298190

  13. Salidroside induces cell-cycle arrest and apoptosis in human breast cancer cells

    SciTech Connect

    Hu, Xiaolan; Zhang, Xianqi; Qiu, Shuifeng; Yu, Daihua; Lin, Shuxin

    2010-07-16

    Research highlights: {yields} Salidroside inhibits the growth of human breast cancer cells. {yields} Salidroside induces cell-cycle arrest of human breast cancer cells. {yields} Salidroside induces apoptosis of human breast cancer cell lines. -- Abstract: Recently, salidroside (p-hydroxyphenethyl-{beta}-D-glucoside) has been identified as one of the most potent compounds isolated from plants of the Rhodiola genus used widely in traditional Chinese medicine, but pharmacokinetic data on the compound are unavailable. We were the first to report the cytotoxic effects of salidroside on cancer cell lines derived from different tissues, and we found that human breast cancer MDA-MB-231 cells (estrogen receptor negative) were sensitive to the inhibitory action of low-concentration salidroside. To further investigate the cytotoxic effects of salidroside on breast cancer cells and reveal possible ER-related differences in response to salidroside, we used MDA-MB-231 cells and MCF-7 cells (estrogen receptor-positive) as models to study possible molecular mechanisms; we evaluated the effects of salidroside on cell growth characteristics, such as proliferation, cell cycle duration, and apoptosis, and on the expression of apoptosis-related molecules. Our results demonstrated for the first time that salidroside induces cell-cycle arrest and apoptosis in human breast cancer cells and may be a promising candidate for breast cancer treatment.

  14. Sonoporation induces apoptosis and cell cycle arrest in human promyelocytic leukemia cells.

    PubMed

    Zhong, Wenjing; Sit, Wai Hung; Wan, Jennifer M F; Yu, Alfred C H

    2011-12-01

    Despite being a transient biophysical phenomenon, sonoporation is known to disturb the homeostasis of living cells. This work presents new evidence on how sonoporation may lead to antiproliferation effects including cell-cycle arrest and apoptosis through disrupting various cell signaling pathways. Our findings were obtained from sonoporation experiments conducted on HL-60 human promyelocytic leukemia cells (with 1% v/v microbubbles; 1 MHz ultrasound; 0.3 or 0.5MPa peak negative pressure; 10% duty cycle; 1 kHz pulse repetition frequency; 1 min exposure period). Membrane resealing in these sonoporated cells was first verified using scanning electron microscopy. Time-lapse flow cytometry analysis of cellular deoxyribonucleic acid (DNA) contents was then performed at four post-sonoporation time points (4 h, 8 h, 12 h and 24 h). Results indicate that an increasing trend in the apoptotic cell population can be observed for at least 12 h after sonoporation, whilst viable sonoporated cells are found to temporarily accumulate in the G(2)/M (gap-2/mitosis) phase of the cell cycle. Further analysis using western blotting reveals that sonoporation-induced apoptosis involves cleavage of poly adenosine diphosphate ribose polymerase (PARP) proteins: a pro-apoptotic hallmark related to loss of DNA repair functionality. Also, mitochondrial signaling seems to have taken part in triggering this cellular event as the expression of two complementary regulators for mitochondrial release of pro-apoptotic molecules, Bcl-2 (B-cell lymphoma 2) and Bax (Bcl-2-associated X), are seen to be imbalanced in sonoporated cells. Furthermore, sonoporation is found to induce cell-cycle arrest through perturbing the expression of various cyclin and Cdk (cyclin-dependent kinase) checkpoint proteins that play an enabling role in cell-cycle progression. These bioeffects should be taken into account when using sonoporation for therapeutic purposes. PMID:22033133

  15. Neferine, an alkaloid from lotus seed embryo, inhibits human lung cancer cell growth by MAPK activation and cell cycle arrest.

    PubMed

    Poornima, Paramasivan; Weng, Ching Feng; Padma, Viswanadha Vijaya

    2014-01-01

    Neferine is the major bisbenzylisoquinoline alkaloid isolated from the seed embryo of a traditional medicinal plant Nelumbo nucifera (Lotus). Epidemiological studies have revealed the therapeutic potential of lotus seed embryo. Although several mechanisms have been proposed, a clear anticancer action mechanism of neferine on lung cancer cells is still not known. Lung cancer is the most common cause of cancer death in the world, and the patients with advanced stage of nonsmall lung cancer require adjunct chemotherapy after surgical resection for the eradication of cancer cells. In this study, the effects of neferine were evaluated and characterized in A549 cells. Neferine induced apoptosis in a dose-dependent manner with the hypergeneration of reactive oxygen species, activation of MAPKs, lipid peroxidation, depletion of cellular antioxidant pool, loss of mitochondrial membrane potential, and intracellular calcium accumulation. Furthermore, neferine treatment leads to the inhibition of nuclear factor kappaB and Bcl2, upregulation of Bax and Bad, release of cytochrome C, activation of caspase cascade, and DNA fragmentation. In addition, neferine could induce p53 and its effector protein p21 and downregulation of cell cycle regulatory protein cyclin D1 thereby inducing G1 cell cycle arrest. These results suggest a novel function of neferine as an apoptosis inducer in lung cancer cells. PMID:23983146

  16. Linalool Induces Cell Cycle Arrest and Apoptosis in Leukemia Cells and Cervical Cancer Cells through CDKIs

    PubMed Central

    Chang, Mei-Yin; Shieh, Den-En; Chen, Chung-Chi; Yeh, Ching-Sheng; Dong, Huei-Ping

    2015-01-01

    Plantaginaceae, a popular traditional Chinese medicine, has long been used for treating various diseases from common cold to cancer. Linalool is one of the biologically active compounds that can be isolated from Plantaginaceae. Most of the commonly used cytotoxic anticancer drugs have been shown to induce apoptosis in susceptible tumor cells. However, the signaling pathway for apoptosis remains undefined. In this study, the cytotoxic effect of linalool on human cancer cell lines was investigated. Water-soluble tetrazolium salts (WST-1) based colorimetric cellular cytotoxicity assay, was used to test the cytotoxic ability of linalool against U937 and HeLa cells, and flow cytometry (FCM) and genechip analysis were used to investigate the possible mechanism of apoptosis. These results demonstrated that linalool exhibited a good cytotoxic effect on U937 and HeLa cells, with the IC50 value of 2.59 and 11.02 μM, respectively, compared with 5-FU with values of 4.86 and 12.31 μM, respectively. After treating U937 cells with linalool for 6 h, we found an increased sub-G1 peak and a dose-dependent phenomenon, whereby these cells were arrested at the G0/G1 phase. Furthermore, by using genechip analysis, we observed that linalool can promote p53, p21, p27, p16, and p18 gene expression. Therefore, this study verified that linalool can arrest the cell cycle of U937 cells at the G0/G1 phase and can arrest the cell cycle of HeLa cells at the G2/M phase. Its mechanism facilitates the expression of the cyclin-dependent kinases inhibitors (CDKIs) p53, p21, p27, p16, and p18, as well as the non-expression of cyclin-dependent kinases (CDKs) activity. PMID:26703569

  17. Niclosamide inhibits the proliferation of human osteosarcoma cell lines by inducing apoptosis and cell cycle arrest.

    PubMed

    Li, Zonghuan; Yu, Yifeng; Sun, Shaoxing; Qi, Baiwen; Wang, Weiyang; Yu, Aixi

    2015-04-01

    Niclosamide, used as an antihelminthic, has demonstrated some properties of anticancer effects. However, its role in osteosarcoma remains to be determined. The aim of this study was to determine the effect of niclosamide on human osteosarcoma cell lines. The human MG-63 and U2OS osteosarcoma cell lines were treated with different concentrations of niclosamide. The cell inhibitory rate was calculated by CCK-8 assay. Cell cycle was detected by flow cytometry. Cell apoptosis was determined by Hoechst 33324 staining, flow cytometry and fluorescence microscope, respectively. The expression of bcl-2, bax and pro-caspase-3 were measured by western blotting. Niclosamide exerted an inhibitory effect on the two cell lines in a time- and dose-dependent manner. Niclosamide was found to induce the arrest of S and G2/M phase in U2OS cells and G2/M in MG-63 cells. Moreover, niclosamide induced apoptosis in MG-63 and U2OS cells. The bax/bcl-2 ratio increased while the expression of pro‑caspase-3 decreased significantly in the two cell lines. The results indicated that niclosamide inhibits proliferation, and induces apoptosis and cell cycle arrest in human osteosarcoma cell lines. PMID:25634333

  18. Diosgenin induces G2/M cell cycle arrest and apoptosis in human hepatocellular carcinoma cells.

    PubMed

    Li, Yongjian; Wang, Xiaorong; Cheng, Silu; Du, Juan; Deng, Zhengting; Zhang, Yani; Liu, Qun; Gao, Jingdong; Cheng, Binbin; Ling, Changquan

    2015-02-01

    Diosgenin is a major compound of Dioscoreaceae plants such as yam, which is used as a drug in Traditional Chinese Medicine, and a common vegetable worldwide. The anticancer effect of diosgenin has been reported in various tumor cells, including leukemia, gastric, colorectal, and breast cancer. However, the activity of diosgenin on hepatocellular carcinoma (HCC) and the underlying mechanism have not been completely investigated. Therefore, we investigated the efficacy and associated mechanisms of diosgenin in HCC cells. Flow cytometric analysis was performed to determine the presence of cell cycle arrest and apopotic cells. Diosgenin significantly inhibited the growth of Bel-7402, SMMC-7721 and HepG2 HCC cells in a concentration-dependent manner. Diosgenin treatment for 24 h induced G2/M cell cycle arrest and apoptosis of hepatoma cells. Diosgenin inhibited Akt phosphorylation and upregulated p21 and p27 expression, but did not alter the expression of p53, suggesting diosgenin-induced upregulation of p21 and p57 is p53-independent in HCC cells. Diosgenin induced HCC cell apoptosis by activating caspase cascades -3, -8 and -9. However, diosgenin did not affect Bcl-2 and Bax levels. In conclusion, results of the present study suggest that diosgenin may be an active anti-HCC agent obtained from natural plants and provide new insights in understanding the mechanisms of diosgenin. PMID:25434486

  19. Knockdown of human deubiquitinase PSMD14 induces cell cycle arrest and senescence

    SciTech Connect

    Byrne, Ann; McLaren, Rajashree P.; Mason, Paul; Chai, Lilly; Dufault, Michael R.; Huang, Yinyin; Liang, Beirong; Gans, Joseph D.; Zhang, Mindy; Carter, Kara; Gladysheva, Tatiana B.; Teicher, Beverly A.; Biemann, Hans-Peter N.; Booker, Michael; Goldberg, Mark A.; Klinger, Katherine W.; Lillie, James; Madden, Stephen L.; Jiang, Yide

    2010-01-15

    The PSMD14 (POH1, also known as Rpn11/MPR1/S13/CepP1) protein within the 19S complex (19S cap; PA700) is responsible for substrate deubiquitination during proteasomal degradation. The role of PSMD14 in cell proliferation and senescence was explored using siRNA knockdown in carcinoma cell lines. Our results reveal that down-regulation of PSMD14 by siRNA transfection had a considerable impact on cell viability causing cell arrest in the G0-G1 phase, ultimately leading to senescence. The molecular events associated with decreased cell proliferation, cell cycle arrest and senescence include down-regulation of cyclin B1-CDK1-CDC25C, down-regulation of cyclin D1 and up-regulation of p21{sup /Cip} and p27{sup /Kip1}. Most notably, phosphorylation of the retinoblastoma protein was markedly reduced in PSMD14 knockdown cells. A comparative study with PSMB5, a subunit of the 20S proteasome, revealed that PSMB5 and PSMD14 have different effects on cell cycle, senescence and associated molecular events. These data support the view that the 19S and 20S subunits of the proteasome have distinct biological functions and imply that targeting 19S and 20S would have distinct molecular consequences on tumor cells.

  20. Citral inhibits cell proliferation and induces apoptosis and cell cycle arrest in MCF-7 cells.

    PubMed

    Chaouki, Wahid; Leger, David Y; Liagre, Bertrand; Beneytout, Jean-Louis; Hmamouchi, Mohamed

    2009-10-01

    Many natural components of plants extract are studied for their beneficial effects on health and particularly on carcinogenesis chemoprevention. In this study, we investigated the effect of citral (3,7-dimethyl-2,6-octadienal), a key component of essential oils extracted from several herbal plants, on the proliferation rate, cell cycle distribution, and apoptosis of the human breast cancer cell line MCF-7. The effects of this compound were also tested on cyclo-oxygenase activity. Citral treatment caused inhibition of MCF-7 cell growth (IC(50)-48 h: 18 x 10(-5)m), with a cycle arrest in G(2)/M phase and apoptosis induction. Moreover, we observed a decrease in prostaglandin E(2) synthesis 48 h after citral treatment. These findings suggest that citral has a potential chemopreventive effect. PMID:19656204

  1. Cell Division and Targeted Cell Cycle Arrest Opens and Stabilizes Basement Membrane Gaps

    PubMed Central

    Matus, David Q.; Chang, Emily; Makohon-Moore, Sasha C.; Hagedorn, Mary A.; Chi, Qiuyi; Sherwood, David R.

    2014-01-01

    Large gaps in basement membrane (BM) occur during organ remodeling and cancer cell invasion. Whether dividing cells, which temporarily reduce their attachment to BM, influence these breaches is unknown. Here we analyse uterine-vulval attachment during development across 21 species of rhabditid nematodes and find that the BM gap that forms between these organs is always bounded by a non-dividing vulval cell. Through cell cycle manipulation and live cell imaging in Caenorhabditis elegans, we show that actively dividing vulval cells facilitate enlargement of this breach by promoting BM movement. In contrast, targeted cell-cycle arrest halts BM movement and limits gap opening. Further, we demonstrate that the BM component laminin accumulates at the BM gap edge and promotes increased integrin levels in non-dividing vulval cells, stabilizing gap position. Together, these studies reveal that cell division can be used as a mechanism to regulate BM breaches, thus controlling the exchange of cells between tissues. PMID:24924309

  2. Appressorium formation in the corn smut fungus Ustilago maydis requires a G2 cell cycle arrest

    PubMed Central

    Castanheira, Sónia; Pérez-Martín, José

    2015-01-01

    Many of the most important plant diseases are caused by fungal pathogens that form specialized cell structures to breach the leaf surface as well as to proliferate inside the plant. To initiate pathogenic development, the fungus responds to a set of inductive cues. Some of them are of extracellular nature (environmental signals) while others respond to intracellular conditions (developmental signals). These signals have to be integrated into a single response that has as a major outcome changes in the morphogenesis of the fungus. The cell cycle regulation is pivotal during these cellular differentiations, and we hypothesized that cell cycle regulation would be likely to provide control points for infection development by fungal pathogens. Although efforts have been done in various fungal systems, there is still limited information available regarding the relationship of these processes with the induction of the virulence programs. Hence, the role of fungal cell cycle regulators –which are wide conserved elements– as true virulence factors, has yet to be defined. Here we discuss the recent finding that the formation of the appressorium, a structure required for plant penetration, in the corn smut fungus Ustilago maydis seems to be incompatible with an active cell cycle and, therefore genetic circuits evolved in this fungus to arrest the cell cycle during the growth of this fungus on plant surface, before the appressorium-mediated penetration into the plant tissue. PMID:25876077

  3. Appressorium formation in the corn smut fungus Ustilago maydis requires a G2 cell cycle arrest.

    PubMed

    Castanheira, Sónia; Pérez-Martín, José

    2015-01-01

    Many of the most important plant diseases are caused by fungal pathogens that form specialized cell structures to breach the leaf surface as well as to proliferate inside the plant. To initiate pathogenic development, the fungus responds to a set of inductive cues. Some of them are of extracellular nature (environmental signals) while others respond to intracellular conditions (developmental signals). These signals have to be integrated into a single response that has as a major outcome changes in the morphogenesis of the fungus. The cell cycle regulation is pivotal during these cellular differentiations, and we hypothesized that cell cycle regulation would be likely to provide control points for infection development by fungal pathogens. Although efforts have been done in various fungal systems, there is still limited information available regarding the relationship of these processes with the induction of the virulence programs. Hence, the role of fungal cell cycle regulators -which are wide conserved elements- as true virulence factors, has yet to be defined. Here we discuss the recent finding that the formation of the appressorium, a structure required for plant penetration, in the corn smut fungus Ustilago maydis seems to be incompatible with an active cell cycle and, therefore genetic circuits evolved in this fungus to arrest the cell cycle during the growth of this fungus on plant surface, before the appressorium-mediated penetration into the plant tissue. PMID:25876077

  4. Photodynamic hyperthermal therapy with indocyanine green (ICG) induces apoptosis and cell cycle arrest in B16F10 murine melanoma cells.

    PubMed

    Radzi, Rozanaliza; Osaki, Tomohiro; Tsuka, Takeshi; Imagawa, Tomohiro; Minami, Saburo; Nakayama, Yuji; Okamoto, Yoshiharu

    2012-05-01

    We examined the effects of photodynamic hyperthemal therapy (PHT), which is a combination of photodynamic therapy (PDT) and hyperthermia (HT), on the apoptosis and cell cycle progression of murine melanoma B16F10 cells. The percentage of apoptotic cell was determined by flow cytometry using fluorescein isothiocyanate (FITC)-conjugated Annexin V and propidium iodide (PI) double staining. The cell cycle analysis was performed by PI staining with flow cytometry. The expression of cyclins and heat shock protein 70 (Hsp70) were examined by a Western blotting analysis. PHT induces death in B16F10 cells, and PHT-mediated apoptosis occurred acutely and persistently in vitro. Our study demonstrated that PHT using indocyanine green (ICG) and near infrared (NIR) light source induces apoptosis and G0/G1 cell cycle arrest in the B16F10 cells. PMID:22146339

  5. Combination of PTEN and {gamma}-Ionizing Radiation Enhances Cell Death and G{sub 2}/M Arrest Through Regulation of AKT Activity and p21 Induction in Non-Small-Cell Lung Cancer Cells

    SciTech Connect

    Park, Jong Kuk; Jung, Hae-Yun; Park, Seon Ho; Kang, Seung Yi; Yi, Mi-Rang; Um, Hong Duck; Hong, Sung Hee

    2008-04-01

    Purpose: To identify the role of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) during {gamma}-ionizing radiation ({gamma}-IR) treatment for non-small-cell lung cancer cells. Methods and Materials: Wild-type PTEN or mutant forms of PTEN plasmids were transfected to construct stable transfectants of the NCI-H1299 non-small-cell lung cancer cell line. Combined effects of PTEN expression and IR treatment were tested using immunoblot, clonogenic, and cell-counting assays. Related signaling pathways were studied with immunoblot and kinase assays. Results: At steady state, stable transfectants showed almost the same proliferation rate but had different AKT phosphorylation patterns. When treated with {gamma}-IR, wild-type PTEN transfectants showed higher levels of cell death compared with mock vector or mutant transfectants, and showed increased G{sub 2}/M cell-cycle arrest accompanied by p21 induction and CDK1 inactivation. NCI-H1299 cells were treated with phosphosinositide-3 kinase (PI3K)/AKT pathway inhibitor (LY29002), resulting in reduced AKT phosphorylation levels. Treatment of NCI-H1299 cells with LY29002 and {gamma}-IR resulted in increased cell-cycle arrest and p21 induction. Endogenous wild-type PTEN-containing NCI-H460 cells were treated with PTEN-specific siRNA and then irradiated with {gamma}-IR: however reduced PTEN levels did not induce cell-cycle arrest or p21 expression. Conclusions: Taken together, these findings indicate that PTEN may modulate cell death or the cell cycle via AKT inactivation by PTEN and {gamma}-IR treatment. We also propose that a PTEN-PI3K/AKT-p21-CDK1 pathway could regulate cell death and the cell cycle by {gamma}-IR treatment.

  6. Cordyceps cicadae induces G2/M cell cycle arrest in MHCC97H human hepatocellular carcinoma cells: a proteomic study

    PubMed Central

    2014-01-01

    Background Cordyceps cicadae is a medicinal fungus that is often used for treating cancer. However, the anticancer mechanisms of C. cicadae are largely unknown. This study aims to investigate the anticancer mechanisms of C. cicadae against hepatocellular carcinoma cells in vitro using a proteomic approach. Methods Human hepatocellular carcinoma MHCC97H cells were treated with a water extract of C. cicadae (0, 100, 250, 500, and 1000 μg/mL) for 48 h and harvested for cell viability assays. The significant differences in protein expression between control and C. cicadae-treated cells were analyzed by two-dimensional gel-based proteomics coupled with matrix-assisted laser desorption ionization-time of flight mass spectrometry. Flow cytometry analysis was employed to investigate the cell cycle and cell death. The anticancer molecular mechanism was analyzed by whole proteome mapping. Results The water extract of C. cicadae (0, 100, 250, 500, and 1000 μg/mL) inhibited the growth of MHCC97H cells in a dose-dependent manner via G2/M phase cell cycle arrest with no evidence of apoptosis. Among the identified proteins with upregulated expression were dynactin subunit 2, N-myc downstream-regulated gene 1, heat shock protein beta-1, alpha-enolase isoform 1, phosphatidylinositol transfer protein, and WD repeat-containing protein 1. Meanwhile, the proteins with downregulated expression were 14-3-3 gamma, BUB3, microtubule-associated protein RP/EB family member 1, thioredoxin-like protein, chloride intracellular channel protein 1, ectonucleoside triphosphate diphosphohydrolase 5, xaa-Pro dipeptidase, enoyl-CoA delta isomerase 1, protein-disulfide isomerase-related chaperone Erp29, hnRNP 2H9B, peroxiredoxin 1, WD-40 repeat protein, and serine/threonine kinase receptor-associated protein. Conclusion The water extract of C. cicadae reduced the growth of human hepatocellular carcinoma MHCC97H cells via G2/M cell cycle arrest. PMID:24872842

  7. PVM/MA-shelled selol nanocapsules promote cell cycle arrest in A549 lung adenocarcinoma cells

    PubMed Central

    2014-01-01

    Background Selol is an oily mixture of selenitetriacylglycerides that was obtained as a semi-synthetic compound containing selenite. Selol is effective against cancerous cells and less toxic to normal cells compared with inorganic forms of selenite. However, Selol’s hydrophobicity hinders its administration in vivo. Therefore, the present study aimed to produce a formulation of Selol nanocapsules (SPN) and to test its effectiveness against pulmonary adenocarcinoma cells (A549). Results Nanocapsules were produced through an interfacial nanoprecipitation method. The polymer shell was composed of poly(methyl vinyl ether-co-maleic anhydride) (PVM/MA) copolymer. The obtained nanocapsules were monodisperse and stable. Both free Selol (S) and SPN reduced the viability of A549 cells, whereas S induced a greater reduction in non-tumor cell viability than SPN. The suppressor effect of SPN was primarily associated to the G2/M arrest of the cell cycle, as was corroborated by the down-regulations of the CCNB1 and CDC25C genes. Apoptosis and necrosis were induced by Selol in a discrete percentage of A549 cells. SPN also increased the production of reactive oxygen species, leading to oxidative cellular damage and to the overexpression of the GPX1, CYP1A1, BAX and BCL2 genes. Conclusions This study presents a stable formulation of PVM/MA-shelled Selol nanocapsules and provides the first demonstration that Selol promotes G2/M arrest in cancerous cells. PMID:25149827

  8. Raman spectrum reveals the cell cycle arrest of Triptolide-induced leukemic T-lymphocytes apoptosis

    NASA Astrophysics Data System (ADS)

    Zhang, Daosen; Feng, Yanyan; Zhang, Qinnan; Su, Xin; Lu, Xiaoxu; Liu, Shengde; Zhong, Liyun

    2015-04-01

    Triptolide (TPL), a traditional Chinese medicine extract, possesses anti-inflammatory and anti-tumor properties. Though some research results have implicated that Triptolide (TPL) can be utilized in the treatment of leukemia, it remains controversial about the mechanism of TPL-induced leukemic T-lymphocytes apoptosis. In this study, combining Raman spectroscopic data, principal component analysis (PCA) and atomic force microscopy (AFM) imaging, both the biochemical changes and morphological changes during TPL-induced cell apoptosis were presented. In contrast, the corresponding data during Daunorubicin (DNR)-induced cell apoptosis was also exhibited. The obtained results showed that Raman spectral changes during TPL-induced cell apoptosis were greatly different from DNR-induced cell apoptosis in the early stage of apoptosis but revealed the high similarity in the late stage of apoptosis. Moreover, above Raman spectral changes were respectively consistent with the morphological changes of different stages during TPL-induced apoptosis or DNR-induced apoptosis, including membrane shrinkage and blebbing, chromatin condensation and the formation of apoptotic bodies. Importantly, it was found that Raman spectral changes with TPL-induced apoptosis or DNR-induced apoptosis were respectively related with the cell cycle G1 phase arrest or G1 and S phase arrest.

  9. Epithelial to Mesenchymal Transition induces cell cycle arrest and parenchymal damage in renal fibrosis

    PubMed Central

    Lovisa, Sara; LeBleu, Valerie S.; Tampe, Björn; Sugimoto, Hikaru; Vadnagara, Komal; Carstens, Julienne L.; Wu, Chia–Chin; Hagos, Yohannes; Burckhardt, Birgitta C.; Pentcheva–Hoang, Tsvetelina; Nischal, Hersharan; Allison, James P.; Zeisberg, Michael; Kalluri, Raghu

    2015-01-01

    Kidney fibrosis is marked by an epithelial–to–mesenchymal transition (EMT) by tubular epithelial cells (TECs). Here we find that during renal fibrosis TECs acquire a partial EMT program during which they remain associated with their basement membrane and express markers of both epithelial and mesenchymal cells. The functional consequence of EMT program during fibrotic injury is an arrest in the G2 phase of the cell cycle and lower expression of several transporters in TECs. We also found that transgenic expression of Twist or Snai1 expression is sufficient to promote prolonged TGF-β1–induced G2 arrest of TECs, limiting their potential for repair and regeneration. Also, in mouse models of experimentally-induced renal fibrosis, conditional deletion of Twist1 or Snai1 in proximal TECs resulted in inhibition of the EMT program and the maintenance of TEC integrity, while restoring proliferation, de–differentiation–associated repair and regeneration of the kidney parenchyma and attenuating interstitial fibrosis. Thus, inhibition of EMT program in TECs during chronic renal injury represents a potential anti–fibrosis therapy PMID:26236991

  10. Ailanthone Inhibits Huh7 Cancer Cell Growth via Cell Cycle Arrest and Apoptosis In Vitro and In Vivo

    PubMed Central

    Zhuo, Zhenjian; Hu, Jianyang; Yang, Xiaolin; Chen, Minfen; Lei, Xueping; Deng, Lijuan; Yao, Nan; Peng, Qunlong; Chen, Zhesheng; Ye, Wencai; Zhang, Dongmei

    2015-01-01

    While searching for natural anti-hepatocellular carcinoma (HCC) components in Ailanthus altissima, we discovered that ailanthone had potent antineoplastic activity against HCC. However, the molecular mechanisms underlying the antitumor effect of ailanthone on HCC have not been examined. In this study, the antitumor activity and the underlying mechanisms of ailanthone were evaluated in vitro and in vivo. Mechanistic studies showed that ailanthone induced G0/G1-phase cell cycle arrest, as indicated by decreased expression of cyclins and CDKs and increased expression of p21 and p27. Our results demonstrated that ailanthone triggered DNA damage characterized by activation of the ATM/ATR pathway. Moreover, ailanthone-induced cell death was associated with apoptosis, as evidenced by an increased ratio of cells in the subG1 phase and by PARP cleavage and caspase activation. Ailanthone-induced apoptosis was mitochondrion-mediated and involved the PI3K/AKT signaling pathway in Huh7 cells. In vivo studies demonstrated that ailanthone inhibited the growth and angiogenesis of tumor xenografts without significant secondary adverse effects, indicating its safety for treating HCC. In conclusion, our study is the first to report the efficacy of ailanthone against Huh7 cells and to elucidate its underlying molecular mechanisms. These findings suggest that ailanthone is a potential agent for the treatment of liver cancer. PMID:26525771

  11. G protein-coupled receptor GPR160 is associated with apoptosis and cell cycle arrest of prostate cancer cells

    PubMed Central

    Zhou, Caihong; Dai, Xinchuan; Chen, Yi; Shen, Yanyan; Lei, Saifei; Xiao, Ting; Bartfai, Tamas; Ding, Jian; Wang, Ming-Wei

    2016-01-01

    G protein-coupled receptors (GPCRs) represent the largest membrane protein family implicated in the therapeutic intervention of a variety of diseases including cancer. Exploration of biological actions of orphan GPCRs may lead to the identification of new targets for drug discovery. This study investigates potential roles of GPR160, an orphan GPCR, in the pathogenesis of prostate cancer. The transcription levels of GPR160 in the prostate cancer tissue samples and cell lines, such as PC-3, LNCaP, DU145 and 22Rv1 cells, were significantly higher than that seen in normal prostate tissue and cells. Knockdown of GPR160 by lentivirus-mediated short hairpin RNA constructs targeting human GPR160 gene (ShGPR160) resulted in prostate cancer cell apoptosis and growth arrest both in vitro and in athymic mice. Differential gene expression patterns in PC-3 cells infected with ShGPR160 or scramble lentivirus showed that 815 genes were activated and 1193 repressed. Functional annotation of differentially expressed genes (DEGs) revealed that microtubule cytoskeleton, cytokine activity, cell cycle phase and mitosis are the most evident functions enriched by the repressed genes, while regulation of programmed cell death, apoptosis and chemotaxis are enriched significantly by the activated genes. Treatment of cells with GPR160-targeting shRNA lentiviruses or duplex siRNA oligos increased the transcription of IL6 and CASP1 gene significantly. Our data suggest that the expression level of endogenous GPR160 is associated with the pathogenesis of prostate cancer. PMID:26871479

  12. Benfluron Induces Cell Cycle Arrest, Apoptosis and Activation of p53 Pathway in MOLT-4 Leukemic Cells.

    PubMed

    Seifrtová, M; Cochlarová, T; Havelek, R; Řezáčová, M

    2015-01-01

    The aim of our study was to determine the effect of potential anti-tumour agent benfluron on human leukemic cells MOLT-4 and elucidate the molecular mechanisms of response of tumour cells to this chemotherapeutic agent. It has been shown that the mechanisms of action of benfluron are complex, but the molecular pathways of the cytostatic effect have remained unknown and the present study contributes to their elucidation. In this work, benfluron reduced viability of the treated cells and induced caspase-mediated apoptosis. The programmed cell death was associated with activation of caspases 8, 9 and 3/7. Moreover, exposure of cells to benfluron resulted in accumulation of the cells primarily in late S and G2/M phases. The changes in the levels of key proteins show that benfluron provoked activation of p53 and induced phosphorylation of p53 on serine 15 and serine 392. The application of benfluron led to phosphorylation of Chk1 on serine 345 and phosphorylation of Chk2 on threonine 68 in the treated cells. Higher doses of benfluron caused phosphorylation of ERK1/2 on threonine 202 and tyrosine 204, whereas JNK and p38 kinases were not activated. In conclusion, benfluron induces apoptosis, cell cycle arrest in late S and G2/M phases, and activates various signalling pathways of the DNA damage response. PMID:26441204

  13. Molecular mechanisms underlying mangiferin-induced apoptosis and cell cycle arrest in A549 human lung carcinoma cells

    PubMed Central

    SHI, WEI; DENG, JIAGANG; TONG, RONGSHENG; YANG, YONG; HE, XIA; LV, JIANZHEN; WANG, HAILIAN; DENG, SHAOPING; QI, PING; ZHANG, DINGDING; WANG, YI

    2016-01-01

    Mangiferin, which is a C-glucosylxanthone (1,3,6,7-tetrahydroxyxanthone-C2-β-D-glucoside) purified from plant sources, has recently gained attention due to its various biological activities. The present study aimed to determine the apoptotic effects of mangiferin on A549 human lung adenocarcinoma cells. In vitro studies demonstrated that mangiferin exerted growth-inhibitory and apoptosis-inducing effects against A549 cells. In addition, mangiferin exhibited anti-tumor properties in A549 xenograft mice in vivo. Mangiferin triggered G2/M phase cell cycle arrest via down-regulating the cyclin-dependent kinase 1-cyclin B1 signaling pathway, and induced apoptotic cell death by inhibiting the protein kinase C-nuclear factor-κB pathway. In addition, mangiferin was able to enhance the antiproliferative effects of cisplatin on A549 cells, thus indicating the potential for a combined therapy. Notably, mangiferin exerted anticancer effects in vivo, where it was able to markedly decrease the volume and weight of subcutaneous tumor mass, and expand the lifespan of xenograft mice. The present study clarified the molecular mechanisms underlying mangiferin-induced antitumor activities, and suggested that mangiferin may be considered a potential antineoplastic drug for the future treatment of cancer. PMID:26935347

  14. Unprecedented inhibition of tubulin polymerization directed by gold nanoparticles inducing cell cycle arrest and apoptosis

    NASA Astrophysics Data System (ADS)

    Choudhury, Diptiman; Xavier, Paulrajpillai Lourdu; Chaudhari, Kamalesh; John, Robin; Dasgupta, Anjan Kumar; Pradeep, Thalappil; Chakrabarti, Gopal

    2013-05-01

    The effect of gold nanoparticles (AuNPs) on the polymerization of tubulin has not been examined till now. We report that interaction of weakly protected AuNPs with microtubules (MTs) could cause inhibition of polymerization and aggregation in the cell free system. We estimate that single citrate capped AuNPs could cause aggregation of ~105 tubulin heterodimers. Investigation of the nature of inhibition of polymerization and aggregation by Raman and Fourier transform-infrared (FTIR) spectroscopies indicated partial conformational changes of tubulin and microtubules, thus revealing that AuNP-induced conformational change is the driving force behind the observed phenomenon. Cell culture experiments were carried out to check whether this can happen inside a cell. Dark field microscopy (DFM) combined with hyperspectral imaging (HSI) along with flow cytometric (FC) and confocal laser scanning microscopic (CLSM) analyses suggested that AuNPs entered the cell, caused aggregation of the MTs of A549 cells, leading to cell cycle arrest at the G0/G1 phase and concomitant apoptosis. Further, Western blot analysis indicated the upregulation of mitochondrial apoptosis proteins such as Bax and p53, down regulation of Bcl-2 and cleavage of poly(ADP-ribose) polymerase (PARP) confirming mitochondrial apoptosis. Western blot run after cold-depolymerization revealed an increase in the aggregated insoluble intracellular tubulin while the control and actin did not aggregate, suggesting microtubule damage induced cell cycle arrest and apoptosis. The observed polymerization inhibition and cytotoxic effects were dependent on the size and concentration of the AuNPs used and also on the incubation time. As microtubules are important cellular structures and target for anti-cancer drugs, this first observation of nanoparticles-induced protein's conformational change-based aggregation of the tubulin-MT system is of high importance, and would be useful in the understanding of cancer therapeutics

  15. Protein-binding, cytotoxicity in vitro and cell cycle arrest of ruthenium(II) polypyridyl complexes

    NASA Astrophysics Data System (ADS)

    Liu, Si-Hong; Zhu, Jian-Wei; Xu, Hui-Hua; Wang, Yan; Liu, Ya-Min; Liang, Jun-Bo; Zhang, Gui-Qiang; Cao, Di-Hua; Lin, Yang-Yang; Wu, Yong; Guo, Qi-Feng

    2016-05-01

    The cytotoxic activity of two Ru(II) complexes against A549, BEL-7402, HeLa, PC-12, SGC-7901 and SiHa cell lines was investigated by MTT method. Complexes 1 and 2 show moderate cytotoxicity toward BEL-7402 cells with an IC50 value of 53.9 ± 3.4 and 39.3 ± 2.1 μM. The effects of the complexes inducing apoptosis, cellular uptake, reactive oxygen species and mitochondrial membrane potential in BEL-7402 cells have been studied by fluorescence microscopy. The percentages of apoptotic and necrotic cells and cell cycle arrest were studied by flow cytometry. The BSA-binding behaviors were investigated by UV/visible and fluorescent spectra.

  16. 5-(2-Carboxyethenyl) isatin derivative induces G{sub 2}/M cell cycle arrest and apoptosis in human leukemia K562 cells

    SciTech Connect

    Zhou, Yao; Zhao, Hong-Ye; Han, Kai-Lin; Yang, Yao; Song, Bin-Bin; Guo, Qian-Nan; Fan, Zhen-Chuan; Zhang, Yong-Min; Teng, Yu-Ou; Yu, Peng

    2014-08-08

    Highlights: • 5-(2-Carboxyethenyl) isatin derivative (HKL 2H) inhibited K562’s proliferation. • HKL 2H caused the morphology change of G{sub 2}/M phase arrest and typical apoptosis. • HKL 2H induced G2/M cell cycle phase arrest in K562 cells. • HKL 2H induced apoptosis in K562 cells through the mitochondrial pathway. - Abstract: Our previous study successfully identified that the novel isatin derivative (E)-methyl 3-(1-(4-methoxybenzyl)-2,3-dioxoindolin-5-yl) acrylate (HKL 2H) acts as an anticancer agent at an inhibitory concentration (IC{sub 50}) level of 3 nM. In this study, the molecular mechanism how HKL 2H induces cytotoxic activity in the human chronic myelogenous leukemia K562 cells was investigated. Flow cytometric analysis showed that the cells were arrested in the G{sub 2}/M phase and accumulated subsequently in the sub-G{sub 1} phase in the presence of HKL 2H. HKL 2H treatment down-regulated the expressions of CDK1 and cyclin B but up-regulated the level of phosphorylated CDK1. Annexin-V staining and the classic DNA ladder studies showed that HKL 2H induced the apoptosis of K562 cells. Our study further showed that HKL 2H treatment caused the dissipation of mitochondrial membrane potential, activated caspase-3 and lowered the Bcl-2/Bax ratio in K562 cells, suggesting that the HKL 2H-causing programmed cell death of K562 cells was caused via the mitochondrial apoptotic pathway. Taken together, our data demonstrated that HKL 2H, a 5-(2-carboxyethenyl) isatin derivative, notably induces G{sub 2}/M cell cycle arrest and mitochondrial-mediated apoptosis in K562 cells, indicating that this compound could be a promising anticancer candidate for further investigation.

  17. Isoalantolactone Inhibits UM-SCC-10A Cell Growth via Cell Cycle Arrest and Apoptosis Induction

    PubMed Central

    Wu, Minjun; Zhang, Hua; Hu, Jiehua; Weng, Zhiyong; Li, Chenyuan; Li, Hong; Zhao, Yan; Mei, Xifan; Ren, Fu; Li, Lihua

    2013-01-01

    Isoalantolactone is a sesquiterpene lactone compound isolated from the roots of Inula helenium L. Previous studies have demonstrated that isoalantolactone possesses antifungal, anti-bacterial, anti-helminthic and anti-proliferative properties in a variety of cells, but there are no studies concerning its effects on head and neck squamous cell carcinoma (HNSCC). In the present study, an MTT assay demonstrated that isoalantolactone has anti-proliferative activity against the HNSCC cell line (UM-SCC-10A). Immunostaining identified that this compound induced UM-SCC-10A cell apoptosis but not necrosis. To explain the molecular mechanisms underlying its effects, flow cytometry and western blot analysis showed that the apoptosis was associated with cell cycle arrest during the G1 phase, up-regulation of p53 and p21, and down-regulation of cyclin D. Furthermore, our results revealed that induction of apoptosis through a mitochondrial pathway led to up-regulation of pro-apoptotic protein expression (Bax), down-regulation of anti-apoptotic protein expression (Bcl-2), mitochondrial release of cytochrome c (Cyto c), reduction of mitochondrial membrane potential (MMP) and activation of caspase-3 (Casp-3). Involvement of the caspase apoptosis pathway was confirmed using caspase inhibitor Z-VAD-FMK pretreatment. Together, our findings suggest that isoalantolactone induced caspase-dependent apoptosis via a mitochondrial pathway and was associated with cell cycle arrest in the G1 phase in UM-SCC-10A cells. Therefore, isoalantolactone may become a potential drug for treating HNSCC. PMID:24098753

  18. Piperine Causes G1 Phase Cell Cycle Arrest and Apoptosis in Melanoma Cells through Checkpoint Kinase-1 Activation

    PubMed Central

    Fofaria, Neel M.; Kim, Sung-Hoon; Srivastava, Sanjay K.

    2014-01-01

    In this study, we determined the cytotoxic effects of piperine, a major constituent of black and long pepper in melanoma cells. Piperine treatment inhibited the growth of SK MEL 28 and B16 F0 cells in a dose and time-dependent manner. The growth inhibitory effects of piperine were mediated by cell cycle arrest of both the cell lines in G1 phase. The G1 arrest by piperine correlated with the down-regulation of cyclin D1 and induction of p21. Furthermore, this growth arrest by piperine treatment was associated with DNA damage as indicated by phosphorylation of H2AX at Ser139, activation of ataxia telangiectasia and rad3-related protein (ATR) and checkpoint kinase 1 (Chk1). Pretreatment with AZD 7762, a Chk1 inhibitor not only abrogated the activation of Chk1 but also piperine mediated G1 arrest. Similarly, transfection of cells with Chk1 siRNA completely protected the cells from G1 arrest induced by piperine. Piperine treatment caused down-regulation of E2F1 and phosphorylation of retinoblastoma protein (Rb). Apoptosis induced by piperine was associated with down-regulation of XIAP, Bid (full length) and cleavage of Caspase-3 and PARP. Furthermore, our results showed that piperine treatment generated ROS in melanoma cells. Blocking ROS by tiron protected the cells from piperine mediated cell cycle arrest and apoptosis. These results suggest that piperine mediated ROS played a critical role in inducing DNA damage and activation of Chk1 leading to G1 cell cycle arrest and apoptosis. PMID:24804719

  19. Galiellalactone induces cell cycle arrest and apoptosis through the ATM/ATR pathway in prostate cancer cells

    PubMed Central

    García, Víctor; Lara-Chica, Maribel; Cantarero, Irene; Sterner, Olov; Calzado, Marco A.; Muñoz, Eduardo

    2016-01-01

    Galiellalactone (GL) is a fungal metabolite that presents antitumor activities on prostate cancer in vitro and in vivo. In this study we show that GL induced cell cycle arrest in G2/M phase, caspase-dependent apoptosis and also affected the microtubule organization and migration ability in DU145 cells. GL did not induce double strand DNA break but activated the ATR and ATM-mediated DNA damage response (DDR) inducing CHK1, H2AX phosphorylation (fH2AX) and CDC25C downregulation. Inhibition of the ATM/ATR activation with caffeine reverted GL-induced G2/M cell cycle arrest, apoptosis and DNA damage measured by fH2AX. In contrast, UCN-01, a CHK1 inhibitor, prevented GL-induced cell cycle arrest but enhanced apoptosis in DU145 cells. Furthermore, we found that GL did not increase the levels of intracellular ROS, but the antioxidant N-acetylcysteine (NAC) completely prevented the effects of GL on fH2AX, G2/M cell cycle arrest and apoptosis. In contrast to NAC, other antioxidants such as ambroxol and EGCG did not interfere with the activity of GL on cell cycle. GL significantly suppressed DU145 xenograft growth in vivo and induced the expression of fH2AX in the tumors. These findings identify for the first time that GL activates DDR in prostate cancer. PMID:26683224

  20. Transcriptional profiling of breast cancer cells in response to mevinolin: Evidence of cell cycle arrest, DNA degradation and apoptosis

    PubMed Central

    MAHMOUD, ALI M.; ABOUL-SOUD, MOURAD A.M.; HAN, JUNKYU; AL-SHEIKH, YAZEED A.; AL-ABD, AHMED M.; EL-SHEMY, HANY A.

    2016-01-01

    The merging of high-throughput gene expression techniques, such as microarray, in the screening of natural products as anticancer agents, is considered the optimal solution for gaining a better understanding of the intervention mechanism. Red yeast rice (RYR), a Chinese dietary product, contains a mixture of hypocholesterolemia agents such as statins. Typically, statins have this effect via the inhibition of HMG-CoA reductase, the key enzyme in the biosynthesis of cholesterol. Recently, statins have been shown to exhibit various beneficial antineoplastic properties through the disruption of tumor angiogenesis and metastatic processes. Mevinolin (MVN) is a member of statins and is abundantly present in RYR. Early experimental trials suggested that the mixed apoptotic/necrotic cell death pathway is activated in response to MVN exposure. In the current study, the cytotoxic profile of MVN was evaluated against MCF-7, a breast cancer-derived cell line. The obtained results indicated that MVN-induced cytotoxicity is multi-factorial involving several regulatory pathways in the cytotoxic effects of MVN on breast cancer cell lines. In addition, MVN-induced transcript abundance profiles inferred from microarrays showed significant changes in some key cell processes. The changes were predicted to induce cell cycle arrest and reactive oxygen species generation but inhibit DNA repair and cell proliferation. This MVN-mediated multi-factorial stress triggered specific programmed cell death (apoptosis) and DNA degradation responses in breast cancer cells. Taken together, the observed MVN-induced effects underscore the potential of this ubiquitous natural compound as a selective anticancer activity, with broad safety margins and low cost compared to benchmarked traditional synthetic chemotherapeutic agents. Additionally, the data support further pre-clinical and clinical evaluations of MVN as a novel strategy to combat breast cancer and overcome drug resistance. PMID:26983896

  1. Transcriptional profiling of breast cancer cells in response to mevinolin: Evidence of cell cycle arrest, DNA degradation and apoptosis.

    PubMed

    Mahmoud, Ali M; Aboul-Soud, Mourad A M; Han, Junkyu; Al-Sheikh, Yazeed A; Al-Abd, Ahmed M; El-Shemy, Hany A

    2016-05-01

    The merging of high-throughput gene expression techniques, such as microarray, in the screening of natural products as anticancer agents, is considered the optimal solution for gaining a better understanding of the intervention mechanism. Red yeast rice (RYR), a Chinese dietary product, contains a mixture of hypocholesterolemia agents such as statins. Typically, statins have this effect via the inhibition of HMG‑CoA reductase, the key enzyme in the biosynthesis of cholesterol. Recently, statins have been shown to exhibit various beneficial antineoplastic properties through the disruption of tumor angiogenesis and metastatic processes. Mevinolin (MVN) is a member of statins and is abundantly present in RYR. Early experimental trials suggested that the mixed apoptotic/necrotic cell death pathway is activated in response to MVN exposure. In the current study, the cytotoxic profile of MVN was evaluated against MCF‑7, a breast cancer‑derived cell line. The obtained results indicated that MVN‑induced cytotoxicity is multi‑factorial involving several regulatory pathways in the cytotoxic effects of MVN on breast cancer cell lines. In addition, MVN‑induced transcript abundance profiles inferred from microarrays showed significant changes in some key cell processes. The changes were predicted to induce cell cycle arrest and reactive oxygen species generation but inhibit DNA repair and cell proliferation. This MVN‑mediated multi‑factorial stress triggered specific programmed cell death (apoptosis) and DNA degradation responses in breast cancer cells. Taken together, the observed MVN‑induced effects underscore the potential of this ubiquitous natural compound as a selective anticancer activity, with broad safety margins and low cost compared to benchmarked traditional synthetic chemotherapeutic agents. Additionally, the data support further pre‑clinical and clinical evaluations of MVN as a novel strategy to combat breast cancer and overcome drug resistance

  2. Viscum Album Var Hot Water Extract Mediates Anti-cancer Effects through G1 Phase Cell Cycle Arrest in SK-Hep1 Human Hepatocarcinoma cells.

    PubMed

    dela Cruz, Joseph Flores; Kim, Yeon Soo; Lumbera, Wenchie Marie Lara; Hwang, Seong Gu

    2015-01-01

    Viscum album var (VAV) also known as mistletoe, has long been categorized as a traditional herbal medicine in Asia. In addition to its immunomodulating activities, mistletoe has also been used in the treatment of chronic hepatic disorders in China and Korea. There are numerous reports showing that VAV possesses anti-cancer effects, however influence on human hepatocarcinoma has never been elucidated. In the present study, hot water extracts of VAV was evaluated for its potential anti-cancer effect in vitro. SK-Hep1 cells were treated with VAV (50-400 ug/ml) for both 24 and 48 hours then cell viability was measured by cell counting kit-8 (CCK-8). Flow cytometry analysis was used to measure the proportion of SK-Hep1 in the different stages of cell cycle. RT-PCR and Western blot analysis were conducted to measure expression of cell cycle arrest related genes and proteins respectively. VAV dose dependently inhibited the proliferation of SK-Hep1 cells without any cytotoxicity with normal Chang liver cell (CCL-13). Flow cytometry analysis showed that VAV extract inhibited the cell cycle of SK-Hep1 cells via G1 phase arrest. RT-PCR and Western blot analysis both revealed that cyclin dependent kinase 2 (Cdk2) and cyclin D1 gene expression were significantly down regulated while p21 was upregulated dose dependently by VAV treatment. Combined down regulation of Cdk2, Cyclin D1 and up regulation of p21 can result in cell death. These results indicate that VAV showed evidence of anti-cancer activity through G1 phase cell cycle arrest in SK-Hep1 cells. PMID:26434853

  3. An Aqueous Extract of Fagonia cretica Induces DNA Damage, Cell Cycle Arrest and Apoptosis in Breast Cancer Cells via FOXO3a and p53 Expression

    PubMed Central

    Lam, Matt; Carmichael, Amtul R.; Griffiths, Helen R.

    2012-01-01

    Background Plants have proved to be an important source of anti-cancer drugs. Here we have investigated the cytotoxic action of an aqueous extract of Fagonia cretica, used widely as a herbal tea-based treatment for breast cancer. Methodology/Principal Findings Using flow cytometric analysis of cells labeled with cyclin A, annexin V and propidium iodide, we describe a time and dose-dependent arrest of the cell cycle in G0/G1 phase of the cell cycle and apoptosis following extract treatment in MCF-7 (WT-p53) and MDA-MB-231 (mutant-p53) human breast cancer cell lines with a markedly reduced effect on primary human mammary epithelial cells. Analysis of p53 protein expression and of its downstream transcription targets, p21 and BAX, revealed a p53 associated growth arrest within 5 hours of extract treatment and apoptosis within 24 hours. DNA double strand breaks measured as γ-H2AX were detected early in both MCF-7 and MDA-MB-231 cells. However, loss of cell viability was only partly due to a p53-driven response; as MDA-MB-231 and p53-knockdown MCF-7 cells both underwent cell cycle arrest and death following extract treatment. p53-independent growth arrest and cytotoxicity following DNA damage has been previously ascribed to FOXO3a expression. Here, in MCF-7 and MDA-MB-231 cells, FOXO3a expression was increased significantly within 3 hours of extract treatment and FOXO3 siRNA reduced the extract-induced loss of cell viability in both cell lines. Conclusions/Significance Our results demonstrate for the first time that an aqueous extract of Fagonia cretica can induce cell cycle arrest and apoptosis via p53-dependent and independent mechanisms, with activation of the DNA damage response. We also show that FOXO3a is required for activity in the absence of p53. Our findings indicate that Fagonia cretica aqueous extract contains potential anti-cancer agents acting either singly or in combination against breast cancer cell proliferation via DNA damage-induced FOXO3a and p53

  4. PD98059 Protects Brain against Cells Death Resulting from ROS/ERK Activation in a Cardiac Arrest Rat Model

    PubMed Central

    Nguyen Thi, Phuong Anh; Chen, Meng-Hua; Li, Nuo; Zhuo, Xiao-Jun; Xie, Lu

    2016-01-01

    The clinical and experimental postcardiac arrest treatment has not reached therapeutic success. The present study investigated the effect of PD98059 (PD) in rats subjected to cardiac arrest (CA)/cardiopulmonary resuscitation (CPR). Experimental rats were divided randomly into 3 groups: sham, CA, and PD. The rats except for sham group were subjected to CA for 5 min followed by CPR operation. Once spontaneous circulation was restored, saline and PD were injected in CA and PD groups, respectively. The survival rates and neurologic deficit scores (NDS) were observed, and the following indices of brain tissue were evaluated: ROS, MDA, SOD, p-ERK1/2/ERK1/2, caspase-3, Bax, Bcl-2, TUNEL positive cells, and double fluorescent staining of p-ERK/TUNEL. Our results indicated that PD treatment significantly reduced apoptotic neurons and improved the survival rates and NDS. Moreover, PD markedly downregulated the ROS, MDA, p-ERK, and caspase-3, Bax and upregulated SOD and Bcl-2 levels. Double staining p-ERK/TUNEL in choroid plexus and cortex showed that cell death is dependent on ERK activation. The findings in present study demonstrated that PD provides neuroprotection via antioxidant activity and antiapoptosis in rats subjected to CA/CPR. PMID:27069530

  5. The neem limonoids azadirachtin and nimbolide induce cell cycle arrest and mitochondria-mediated apoptosis in human cervical cancer (HeLa) cells.

    PubMed

    Priyadarsini, R Vidya; Murugan, R Senthil; Sripriya, P; Karunagaran, D; Nagini, S

    2010-06-01

    Limonoids from the neem tree (Azadirachta indica) have attracted considerable research attention in recent years owing to their potent antioxidant and anti-proliferative effects. The present study was designed to investigate the cellular and molecular mechanisms by which azadirachtin and nimbolide exert cytotoxic effects in the human cervical cancer (HeLa) cell line. Both azadirachtin and nimbolide significantly suppressed the viability of HeLa cells in a dose-dependent manner by inducing cell cycle arrest at G0/G1 phase accompanied by p53-dependent p21 accumulation and down-regulation of the cell cycle regulatory proteins cyclin B, cyclin D1 and PCNA. Characteristic changes in nuclear morphology, presence of a subdiploid peak and annexin-V staining pointed to apoptosis as the mode of cell death. Increased generation of reactive oxygen species with decline in the mitochondrial transmembrane potential and release of cytochrome c confirmed that the neem limonoids transduced the apoptotic signal via the mitochondrial pathway. Altered expression of the Bcl-2 family of proteins, inhibition of NF-kappaB activation and over-expression of caspases and survivin provide compelling evidence that azadirachtin and nimbolide induce a shift of balance toward a pro-apoptotic phenotype. Antioxidants such as azadirachtin and nimbolide that can simultaneously arrest the cell cycle and target multiple molecules involved in mitochondrial apoptosis offer immense potential as anti-cancer therapeutic drugs. PMID:20429769

  6. Isodeoxyelephantopin from Elephantopus scaber (Didancao) induces cell cycle arrest and caspase-3-mediated apoptosis in breast carcinoma T47D cells and lung carcinoma A549 cells

    PubMed Central

    2014-01-01

    Background Isodeoxyelephantopin (IDOE) isolated from Elephantopus scaber L. (Didancao) is used in Chinese medicine for the treatment of some types of cancer. The anti-cancer mechanism of IDOE remains unclear. This study aims to investigate the antiproliferative activity of IDOE on breast carcinoma T47D cells and lung carcinoma A549 cells. Methods The growth inhibitory effects of IDOE on breast carcinoma T47D cells, lung carcinoma A549 cells, and normal lymphocytes were evaluated by the MTT assay. Morphological analysis of apoptosis induction was performed by acridine orange/ethidium bromide dual-staining and Hoechst 33342 nuclear staining. The cell cycle profile, caspase-3 expression, and annexin V staining were evaluated by flow cytometry. Results IDOE inhibited the growth of A549 and T47D cells in a dose- and time-dependent manner with IC50 values of 10.46 and 1.3 μg/mL, respectively. IDOE was not significantly toxic to normal lymphocytes. The cells became detached from the monolayer and rounded up, had fragmented nuclei and condensed chromatin, and the numbers of apoptotic cells increased (P = 0.0003). IDOE-induced cell death was associated with activated caspase-3 expression followed by cell cycle arrest at G2/M phase. Conclusions IDOE inhibited the proliferation of breast cancer cells and lung carcinoma cells and induced caspase-3-mediated apoptosis and cell cycle arrest in the treated cells. PMID:24742378

  7. Glucocorticoid receptor-mediated cell cycle arrest is achieved through distinct cell-specific transcriptional regulatory mechanisms.

    PubMed Central

    Rogatsky, I; Trowbridge, J M; Garabedian, M J

    1997-01-01

    Glucocorticoids inhibit proliferation of many cell types, but the events leading from the activated glucocorticoid receptor (GR) to growth arrest are not understood. Ectopic expression and activation of GR in human osteosarcoma cell lines U2OS and SAOS2, which lack endogenous receptors, result in a G1 cell cycle arrest. GR activation in U2OS cells represses expression of the cyclin-dependent kinases (CDKs) CDK4 and CDK6 as well as their regulatory partner, cyclin D3, leading to hypophosphorylation of the retinoblastoma protein (Rb). We also demonstrate a ligand-dependent reduction in the expression of E2F-1 and c-Myc, transcription factors involved in the G1-to-S-phase transition. Mitogen-activated protein kinase, CDK2, cyclin E, and the CDK inhibitors (CDIs) p27 and p21 are unaffected by receptor activation in U2OS cells. The receptor's N-terminal transcriptional activation domain is not required for growth arrest in U2OS cells. In Rb-deficient SAOS2 cells, however, the expression of p27 and p21 is induced upon receptor activation. Remarkably, in SAOS2 cells that express a GR deletion derivative lacking the N-terminal transcriptional activation domain, induction of CDI expression is abolished and the cells fail to undergo ligand-dependent cell cycle arrest. Similarly, murine S49 lymphoma cells, which, like SAOS2 cells, lack Rb, require the N-terminal activation domain for growth arrest and induce CDI expression upon GR activation. These cell-type-specific differences in receptor domains and cellular targets linking GR activation to cell cycle machinery suggest two distinct regulatory mechanisms of GR-mediated cell cycle arrest: one involving transcriptional repression of G1 cyclins and CDKs and the other involving enhanced transcription of CDIs by the activated receptor. PMID:9154817

  8. Stilbene 5c, A Microtubule Poison with Vascular Disrupting Properties That Induces Multiple Modes of Growth Arrest and Cell Death

    PubMed Central

    Alotaibi, M.R.; Asnake, B.; Xu, Di; Beckman, M.J.; Durrant, D; Simoni, D; Baruchello, R; Lee, R. M.; Schwartz, E.L.; Gewirtz, D.A.

    2013-01-01

    The stilbene derivative, cis-3, 4’, 5-trimethoxy-3’-aminostilbene (stilbene 5c), is a potentially potent antitumor agent that acts via binding to the colchicine-binding site in tubulin. The current studies were designed to investigate the effectiveness of stilbene 5c against the HCT-116 human colon cancer cell line and B16/F10 melanoma cells as well as human endothelial cell formation and tumor perfusion. Stilbene 5c produced a time-dependent decrease in cell viability in both cell lines and the capacity of the cells to proliferate was not restored upon removal of the drug. Treatment with stilbene 5c also promoted both senescence and autophagy in both cell lines. TUNEL and annexin 5 staining indicated that apoptosis also occurs in stilbene 5c-treated HCT-116 cells, but not in B16/F10 melanoma cells. DAPI staining revealed morphological changes in the cell nuclei (binucleated and micronucleated cells) indicative of mitotic catastrophe in HCT-116 cells but not in the B16/F10 melanoma cells. p53-null HCT-116 cells demonstrated a similar growth arrest/cell death response to stilbene as p53-wild type HCT-116 cells. Stilbene 5c also completely inhibited human endothelial cell tube formation on Matrigel, consistent with potential anti-angiogenic actions. Using a new method developed for monitoring the pharmacodynamic effects of stilbene 5c in vivo, we found that a single injection of stilbene 5c reduced tumor perfusion by 65% at 4 hours, returning to baseline by 24 hours, while subsequent daily injections of stilbene 5c produced progressively larger reductions and smaller rebounds. This work indicates that stilbene 5c could potentially be effective against melanoma and colon cancer through the promotion of multiple modes of growth arrest and cell death coupled with anti-angiogenic and antivascular actions. PMID:24144631

  9. Stilbene 5c, a microtubule poison with vascular disrupting properties that induces multiple modes of growth arrest and cell death.

    PubMed

    Alotaibi, M R; Asnake, B; Di, Xu; Beckman, M J; Durrant, D; Simoni, D; Baruchello, R; Lee, R M; Schwartz, E L; Gewirtz, D A

    2013-12-15

    The stilbene derivative, cis-3,4',5-trimethoxy-3'-aminostilbene (stilbene 5c), is a potentially potent antitumor agent that acts via binding to the colchicine-binding site in tubulin. The current studies were designed to investigate the effectiveness of stilbene 5c against the HCT-116 human colon cancer cell line and B16/F10 melanoma cells as well as human endothelial cell tube formation and tumor perfusion. Stilbene 5c produced a time-dependent decrease in cell viability in both cell lines and the capacity of the cells to proliferate was not restored upon removal of the drug. Treatment with stilbene 5c also promoted both senescence and autophagy in both cell lines. TUNEL and annexin 5 staining indicated that apoptosis also occurs in stilbene 5c-treated HCT-116 cells, but not in B16/F10 melanoma cells. DAPI staining revealed morphological changes in the cell nuclei (binucleated and micronucleated cells) indicative of mitotic catastrophe in HCT-116 cells but not in the B16/F10 melanoma cells. p53-null HCT-116 cells demonstrated a similar growth arrest/cell death response to stilbene as p53-wild type HCT-116 cells. Stilbene 5c also completely inhibited human endothelial cell tube formation on Matrigel, consistent with potential anti-angiogenic actions. Using a new method developed for monitoring the pharmacodynamic effects of stilbene 5c in vivo, we found that a single injection of stilbene 5c reduced tumor perfusion by 65% at 4h, returning to baseline by 24h, while subsequent daily injections of stilbene 5c produced progressively larger reductions and smaller rebounds. This work indicates that stilbene 5c could potentially be effective against melanoma and colon cancer through the promotion of multiple modes of growth arrest and cell death coupled with anti-angiogenic and antivascular actions. PMID:24144631

  10. Tocotrienol-rich fraction of palm oil induces cell cycle arrest and apoptosis selectively in human prostate cancer cells

    SciTech Connect

    Srivastava, Janmejai K.; Gupta, Sanjay . E-mail: sanjay.gupta@case.edu

    2006-07-28

    One of the requisite of cancer chemopreventive agent is elimination of damaged or malignant cells through cell cycle inhibition or induction of apoptosis without affecting normal cells. In this study, employing normal human prostate epithelial cells (PrEC), virally transformed normal human prostate epithelial cells (PZ-HPV-7), and human prostate cancer cells (LNCaP, DU145, and PC-3), we evaluated the growth-inhibitory and apoptotic effects of tocotrienol-rich fraction (TRF) extracted from palm oil. TRF treatment to PrEC and PZ-HPV-7 resulted in almost identical growth-inhibitory responses of low magnitude. In sharp contrast, TRF treatment resulted in significant decreases in cell viability and colony formation in all three prostate cancer cell lines. The IC{sub 5} values after 24 h TRF treatment in LNCaP, PC-3, and DU145 cells were in the order 16.5, 17.5, and 22.0 {mu}g/ml. TRF treatment resulted in significant apoptosis in all the cell lines as evident from (i) DNA fragmentation (ii) fluorescence microscopy, and (iii) cell death detection ELISA, whereas the PrEC and PZ-HPV-7 cells did not undergo apoptosis, but showed modestly decreased cell viability only at a high dose of 80 {mu}g/ml. In cell cycle analysis, TRF (10-40 {mu}g/ml) resulted in a dose-dependent G0/G1 phase arrest and sub G1 accumulation in all three cancer cell lines but not in PZ-HPV-7 cells. These results suggest that the palm oil derivative TRF is capable of selectively inhibiting cellular proliferation and accelerating apoptotic events in prostate cancer cells. TRF offers significant promise as a chemopreventive and/or therapeutic agent against prostate cancer.

  11. Specific phase arrest of cell cycle restores cell viability against tRNA cleavage by killer toxin.

    PubMed

    Shigematsu, Megumi; Ogawa, Tetsuhiro; Kitamoto, Hiroko K; Hidaka, Makoto; Masaki, Haruhiko

    2012-04-20

    Zymocin and PaT are killer toxins that induce cell cycle arrest of sensitive yeast cells in G1 and S phase, respectively. Recent studies have revealed that these two toxins cleave specific tRNAs, indicating that the cell growth impairment is due to the tRNA cleavage. Additionally, we have previously shown that the active domain of colicin D (D-CRD), which also cleaves specific Escherichia coli tRNAs, statically impairs growth when expressed in yeast cells. To verify that phase-specific cell cycle arrest is also induced by the expression of D-CRD, D-CRD and the subunits of zymocin and PaT that have tRNA cleaving activity were expressed in yeast cells and cell cycle status was analyzed. Our results indicate that phase-specific arrest does not commonly occur by tRNA cleavage, and it saves the cell viability. Furthermore, the extent of protein synthesis impairment may determine the phase specificity of cell cycle arrest. PMID:22450321

  12. ATR CONTRIBUTES TO CELL CYCLE ARREST AND SURVIVAL AFTER CISPLATIN BUT NOT OXALIPLATIN1

    PubMed Central

    Lewis, Kriste A.; Lilly, Kia K.; Reynolds, Evelyn A.; Sullivan, William P.; Kaufmann, Scott H.; Cliby, William A.

    2009-01-01

    The DNA cross-linking agents cisplatin and oxaliplatin are widely used in the treatment of human cancer. Lesions produced by these agents are widely known to activate the G1 and G2 cell cycle checkpoints. Less is known about the role of the intra-S phase checkpoint in the response to these agents. In the present study, two different cell lines expressing a dominant negative kinase-dead (kd) version of the ATR (ataxia telangiectasia and rad3-related) kinase in an inducible fashion were examined for their responses to these two platinating agents and a variety of other DNA cross-linking drugs. Expression of the kdATR allele markedly sensitized the cells to cisplatin, but not oxaliplatin, as assessed by inhibition of colony formation, induction of apoptosis, and cell cycle analysis. Similar differences in survival were noted for melphalan (ATR-dependent) and 4-hydroperoxycyclophosphamide (4HC) (ATR-independent). Further experiments demonstrated that ATR function is not necessary for removal of Pt-DNA adducts. The predominant difference between the responses to the two platinum drugs was presence of a drug-specific ATR-dependent S phase arrest after cisplatin but not oxaliplatin. These results indicate that involvement of ATR in the response to DNA cross-linking agents is lesion specific. This observation might need to be taken into account in the development and use of ATR or Chk1 inhibitors. PMID:19372558

  13. Src kinase inhibitors induce apoptosis and mediate cell cycle arrest in lymphoma cells.

    PubMed

    Nowak, Daniel; Boehrer, Simone; Hochmuth, Simone; Trepohl, Bettina; Hofmann, Wencke; Hoelzer, Dieter; Hofmann, Wolf-Karsten; Mitrou, Paris S; Ruthardt, Martin; Chow, Kai Uwe

    2007-10-01

    Src kinases are involved in multiple cellular contexts such as proliferation, adhesion, tumor invasiveness, angiogenesis, cell cycle control and apoptosis. We here demonstrate that three newly developed dual selective Src/Abl kinase inhibitors (SrcK-I) (AZM559756, AZD0530 and AZD0424) are able to induce apoptosis and cell cycle arrest in BCR-ABL, c-KIT and platelet-derived growth factor-negative lymphoma cell lines. Treatment of DOHH-2, WSU-NHL, Raji, Karpas-299, HUT78 and Jurkat cells with SrcK-I revealed that the tested substances were effective on these parameters in the cell lines DOHH-2 and WSU-NHL, whereas the other tested cell lines remained unaffected. Phosphorylation of Lyn and in particular Lck were affected most heavily by treatment with the SrcK-I. Extrinsic as well as intrinsic apoptosis pathways were activated and elicited unique expressional patterns of apoptosis-relevant proteins such as downregulation of survivin, Bcl-XL and c-FLIP. Protein levels of c-abl were downregulated and Akt phosphorylation was decreased by treatment with SrcK-I. Basal expression levels of c-Myc were notably lower in sensitive cell lines as compared with nonsensitive cell lines, possibly providing an explanation for sensitivity versus resistance against these novel substances. This study provides the first basis for establishing novel SrcK-I as weapons in the arsenal against lymphoma cells. PMID:17704648

  14. Dual CDK4/CDK6 Inhibition Induces Cell Cycle Arrest and Senescence in Neuroblastoma

    PubMed Central

    Rader, JulieAnn; Russell, Mike R.; Hart, Lori S.; Nakazawa, Michael S.; Belcastro, Lili T.; Martinez, Daniel; Li, Yimei; Carpenter, Erica L.; Attiyeh, Edward F.; Diskin, Sharon J.; Kim, Sunkyu; Parasuraman, Sudha; Caponigro, Giordano; Schnepp, Robert W.; Wood, Andrew C.; Pawel, Bruce; Cole, Kristina A.; Maris, John M.

    2013-01-01

    Purpose Neuroblastoma is a pediatric cancer that continues to exact significant morbidity and mortality. Recently, a number of cell cycle proteins, particularly those within the Cyclin D/CDK4/CDK6/RB network, have been shown to exert oncogenic roles in neuroblastoma, suggesting that their therapeutic exploitation might improve patient outcomes. Experimental Procedures We evaluated the effect of dual CDK4/CDK6 inhibition on neuroblastoma viability using LEE011, a highly specific CDK4/6 inhibitor. Results Treatment with LEE011 significantly reduced proliferation in 12 of 17 human neuroblastoma-derived cell lines by inducing cytostasis at nanomolar concentrations (mean IC50 = 307 ± 68 nM in sensitive lines). LEE011 caused cell cycle arrest and cellular senescence that was attributed to dose-dependent decreases in phosphorylated RB and FOXM1, respectively. In addition, responsiveness of neuroblastoma xenografts to LEE011 translated to the in vivo setting in that there was a direct correlation of in vitro IC50 values with degree of subcutaneous xenograft growth delay. While our data indicate that neuroblastomas sensitive to LEE011 were more likely to contain genomic amplification of MYCN (p = 0.01), the identification of additional clinically accessible biomarkers is of high importance. Conclusions Taken together, our data show that LEE011 is active in a large subset of neuroblastoma cell line and xenograft models, and supports the clinical development of this CDK4/6 inhibitor as a therapy for patients with this disease. PMID:24045179

  15. Nucleolin down-regulation is involved in ADP-induced cell cycle arrest in S phase and cell apoptosis in vascular endothelial cells.

    PubMed

    Wang, Wenmeng; Luo, Junqing; Xiang, Fang; Liu, Xueting; Jiang, Manli; Liao, Lingjuan; Hu, Jinyue

    2014-01-01

    High concentration of extracellular ADP has been reported to induce cell apoptosis, but the molecular mechanisms remain not fully elucidated. In this study, we found by serendipity that ADP treatment of human umbilical vein endothelial cells (HUVEC) and human aortic endothelial cells (HAEC) down-regulated the protein level of nucleolin in a dose- and time-dependent manner. ADP treatment did not decrease the transcript level of nucloelin, suggesting that ADP might induce nucleolin protein degradation. HUVEC and HAEC expressed ADP receptor P2Y13 receptor, but did not express P2Y1 or P2Y12 receptors. However, P2Y1, 12, 13 receptor antagonists MRS2179, PSB0739, MRS2211 did not inhibit ADP-induced down-regulation of nucleolin. Moreover, MRS2211 itself down-regulated nucleolin protein level. In addition, 2-MeSADP, an agonist for P2Y1, 12 and 13 receptors, did not down-regulate nucleolin protein. These results suggested that ADP-induced nucleolin down-regulation was not due to the activation of P2Y1, 12, or 13 receptors. We also found that ADP treatment induced cell cycle arrest in S phase, cell apoptosis and cell proliferation inhibition via nucleolin down-regulation. The over-expression of nucleolin by gene transfer partly reversed ADP-induced cell cycle arrest, cell apoptosis and cell proliferation inhibition. Furthermore, ADP sensitized HUVEC to cisplatin-induced cell death by the down-regulation of Bcl-2 expression. Taken together, we found, for the first time to our knowledge, a novel mechanism by which ADP regulates cell proliferation by induction of cell cycle arrest and cell apoptosis via targeting nucelolin. PMID:25290311

  16. Nucleolin Down-Regulation Is Involved in ADP-Induced Cell Cycle Arrest in S Phase and Cell Apoptosis in Vascular Endothelial Cells

    PubMed Central

    Wang, Wenmeng; Luo, Junqing; Xiang, Fang; Liu, Xueting; Jiang, Manli; Liao, Lingjuan; Hu, Jinyue

    2014-01-01

    High concentration of extracellular ADP has been reported to induce cell apoptosis, but the molecular mechanisms remain not fully elucidated. In this study, we found by serendipity that ADP treatment of human umbilical vein endothelial cells (HUVEC) and human aortic endothelial cells (HAEC) down-regulated the protein level of nucleolin in a dose- and time-dependent manner. ADP treatment did not decrease the transcript level of nucloelin, suggesting that ADP might induce nucleolin protein degradation. HUVEC and HAEC expressed ADP receptor P2Y13 receptor, but did not express P2Y1 or P2Y12 receptors. However, P2Y1, 12, 13 receptor antagonists MRS2179, PSB0739, MRS2211 did not inhibit ADP-induced down-regulation of nucleolin. Moreover, MRS2211 itself down-regulated nucleolin protein level. In addition, 2-MeSADP, an agonist for P2Y1, 12 and 13 receptors, did not down-regulate nucleolin protein. These results suggested that ADP-induced nucleolin down-regulation was not due to the activation of P2Y1, 12, or 13 receptors. We also found that ADP treatment induced cell cycle arrest in S phase, cell apoptosis and cell proliferation inhibition via nucleolin down-regulation. The over-expression of nucleolin by gene transfer partly reversed ADP-induced cell cycle arrest, cell apoptosis and cell proliferation inhibition. Furthermore, ADP sensitized HUVEC to cisplatin-induced cell death by the down-regulation of Bcl-2 expression. Taken together, we found, for the first time to our knowledge, a novel mechanism by which ADP regulates cell proliferation by induction of cell cycle arrest and cell apoptosis via targeting nucelolin. PMID:25290311

  17. Critical Role of AMPK/FoxO3A Axis in Globular Adiponectin-Induced Cell Cycle Arrest and Apoptosis in Cancer Cells.

    PubMed

    Shrestha, Anup; Nepal, Saroj; Kim, Mi Jin; Chang, Jae Hoon; Kim, Sang-Hyun; Jeong, Gil-Saeng; Jeong, Chul-Ho; Park, Gyu Hwan; Jung, Sunghee; Lim, Jaecheong; Cho, Eunha; Lee, Soyoung; Park, Pil-Hoon

    2016-02-01

    Adiponectin predominantly secreted from adipose tissue has exhibited potent anti-proliferative properties in cancer cells via modulating cell cycle and apoptosis. FoxO3A, a Forkhead box O member of the transcription factor, plays a critical role in modulating expression of genes involved in cell death and/or survival. In this study, we investigated the role of FoxO3A signaling in anti-cancer activities of adiponectin. Herein, we have shown that treatment with globular adiponectin (gAcrp) increases p27 but decreases cyclinD1 expression in human hepatoma (HepG2) and breast (MCF-7) cancer cells. Gene ablation of FoxO3A prevented gAcrp-induced increase in p27 and decreased in cyclin D1 expression, and further ameliorated cell cycle arrest by gAcrp, indicating a critical role of FoxO3A in gAcrp-induced cell cycle arrest of cancer cells. Moreover, treatment with gAcrp also induced caspase-3/7 activation and increased Fas ligand (FasL) expression in both HepG2 and MCF-7 cells. Transfection with FoxO3A siRNA inhibited gAcrp-induced caspase-3/7 activation and FasL expression, suggesting that FoxO3A signaling also plays an important role in gAcrp-induced apoptosis of cancer cells. We also found that gene silencing of AMPK prevented gAcrp-induced nuclear translocation of FoxO3A in HepG2 and MCF-7 cells. In addition, suppression of AMPK also blocked gAcrp-induced cell cycle arrest and further attenuated gAcrp-induced caspase-3/7 activation, indicating that AMPK signaling plays a pivotal role in both gAcrp-induced cell cycle arrest and apoptosis via acting as an upstream signaling of FoxO3A. Taken together, our findings demonstrated that AMPK/FoxO3A axis plays a cardinal role in anti-proliferative effect of adiponectin in cancer cells. PMID:26089158

  18. Role of the retinoblastoma protein in cell cycle arrest mediated by a novel cell surface proliferation inhibitor

    NASA Technical Reports Server (NTRS)

    Enebo, D. J.; Fattaey, H. K.; Moos, P. J.; Johnson, T. C.; Spooner, B. S. (Principal Investigator)

    1994-01-01

    A novel cell regulatory sialoglycopeptide (CeReS-18), purified from the cell surface of bovine cerebral cortex cells has been shown to be a potent and reversible inhibitor of proliferation of a wide array of fibroblasts as well as epithelial-like cells and nontransformed and transformed cells. To investigate the possible mechanisms by which CeReS-18 exerts its inhibitory action, the effect of the inhibitor on the posttranslational regulation of the retinoblastoma susceptibility gene product (RB), a tumor suppressor gene, has been examined. It is shown that CeReS-18 mediated cell cycle arrest of both human diploid fibroblasts (HSBP) and mouse fibroblasts (Swiss 3T3) results in the maintenance of the RB protein in the hypophosphorylated state, consistent with a late G1 arrest site. Although their normal nontransformed counterparts are sensitive to cell cycle arrest mediated by CeReS-18, cell lines lacking a functional RB protein, through either genetic mutation or DNA tumor virus oncoprotein interaction, are less sensitive. The refractory nature of these cells is shown to be independent of specific surface receptors for the inhibitor, and another tumor suppressor gene (p53) does not appear to be involved in the CeReS-18 inhibition of cell proliferation. The requirement for a functional RB protein product, in order for CeReS-18 to mediate cell cycle arrest, is discussed in light of regulatory events associated with density-dependent growth inhibition.

  19. RAD9-dependent G1 arrest defines a second checkpoint for damaged DNA in the cell cycle of Saccharomyces cerevisiae.

    PubMed Central

    Siede, W; Friedberg, A S; Friedberg, E C

    1993-01-01

    Exposure of the yeast Saccharomyces cerevisiae to ultraviolet (UV) light, the UV-mimetic chemical 4-nitroquinoline-1-oxide (4NQO), or gamma radiation after release from G1 arrest induced by alpha factor results in delayed resumption of the cell cycle. As is the case with G2 arrest following ionizing radiation damage [Weinert, T. A. & Hartwell, L. H. (1988) Science 241, 317-322], the normal execution of DNA damage-induced G1 arrest depends on a functional yeast RAD9 gene. We suggest that the RAD9 gene product may interact with cellular components common to the G1/S and G2/M transition points in the cell cycle of this yeast. These observations define a checkpoint in the eukaryotic cell cycle that may facilitate the repair of lesions that are otherwise processed to lethal and/or mutagenic damage during DNA replication. This checkpoint apparently operates after the mating pheromone-induced G1 arrest point but prior to replicative DNA synthesis, S phase-associated maximal induction of histone H2A mRNA, and bud emergence. Images Fig. 4 PMID:8367452

  20. Clove Extract Inhibits Tumor Growth and Promotes Cell Cycle Arrest and Apoptosis

    PubMed Central

    Liu, Haizhou; Schmitz, John C.; Wei, Jianteng; Cao, Shousong; Beumer, Jan H.; Strychor, Sandra; Cheng, Linyou; Liu, Ming; Wang, Cuicui; Wu, Ning; Zhao, Xiangzhong; Zhang, Yuyan; Liao, Joshua; Chu, Edward; Lin, Xiukun

    2014-01-01

    Cloves (Syzygium aromaticum) have been used as a traditional Chinese medicinal herb for thousands of years. Cloves possess antiseptic, antibacterial, antifungal, and antiviral properties, but their potential anticancer activity remains unknown. In this study, we investigated the in vitro and in vivo antitumor effects and biological mechanisms of ethyl acetate extract of cloves (EAEC) and the potential bioactive components responsible for its antitumor activity. The effects of EAEC on cell growth, cell cycle distribution, and apoptosis were investigated using human cancer cell lines. The molecular changes associated with the effects of EAEC were analyzed by Western blot and (qRT)-PCR analysis. The in vivo effect of EAEC and its bioactive component was investigated using the HT-29 tumor xenograft model. We identified oleanolic acid (OA) as one of the components of EAEC responsible for its antitumor activity. Both EAEC and OA display cytotoxicity against several human cancer cell lines. Interestingly, EAEC was superior to OA and the chemotherapeutic agent 5-fluorouracil at suppressing growth of colon tumor xenografts. EAEC promoted G0/G1 cell cycle arrest and induced apoptosis in a dose-dependent manner. Treatment with EAEC and OA selectively increased protein expression of p21WAF1/Cip1 and γ-H2AX and downregulated expression of cell cycle-regulated proteins. Moreover, many of these changes were at the mRNA level, suggesting transcriptional regulation by EAEC treatment. Our results demonstrate that clove extract may represent a novel therapeutic herb for the treatment of colorectal cancer, and OA appears to be one of the bioactive components. PMID:24854101

  1. Enhanced induction of cell cycle arrest and apoptosis via the mitochondrial membrane potential disruption in human U87 malignant glioma cells by aloe emodin.

    PubMed

    Ismail, Samhani; Haris, Khalilah; Abdul Ghani, Abdul Rahman Izaini; Abdullah, Jafri Malin; Johan, Muhammad Farid; Mohamed Yusoff, Abdul Aziz

    2013-09-01

    Aloe emodin, one of the active compounds found in Aloe vera leaves, plays an important role in the regulation of cell growth and death. It has been reported to promote the anti-cancer effects in various cancer cells by inducing apoptosis. However, the mechanism of inducing apoptosis by this agent is poorly understood in glioma cells. This research is to investigate the apoptosis and cell cycle arrest inducing by aloe emodin on U87 human malignant glioma cells. Aloe emodin showed a time- and dose-dependent inhibition of U87 cells proliferation and decreased the percentage of viable U87 cells via the induction of apoptosis. Characteristic morphological changes, such as the formation of apoptotic bodies, were observed with confocal microscope by Annexin V-FITC/PI staining, supporting our viability study and flow cytometry analysis results. Our data also demonstrated that aloe emodin arrested the cell cycle in the S phase and promoted the loss of mitochondrial membrane potential in U87 cells that indicated the early event of the mitochondria-induced apoptotic pathway. PMID:23869465

  2. 53BP1 and USP28 mediate p53-dependent cell cycle arrest in response to centrosome loss and prolonged mitosis

    PubMed Central

    Fong, Chii Shyang; Mazo, Gregory; Das, Tuhin; Goodman, Joshua; Kim, Minhee; O'Rourke, Brian P; Izquierdo, Denisse; Tsou, Meng-Fu Bryan

    2016-01-01

    Mitosis occurs efficiently, but when it is disturbed or delayed, p53-dependent cell death or senescence is often triggered after mitotic exit. To characterize this process, we conducted CRISPR-mediated loss-of-function screens using a cell-based assay in which mitosis is consistently disturbed by centrosome loss. We identified 53BP1 and USP28 as essential components acting upstream of p53, evoking p21-dependent cell cycle arrest in response not only to centrosome loss, but also to other distinct defects causing prolonged mitosis. Intriguingly, 53BP1 mediates p53 activation independently of its DNA repair activity, but requiring its interacting protein USP28 that can directly deubiquitinate p53 in vitro and ectopically stabilize p53 in vivo. Moreover, 53BP1 can transduce prolonged mitosis to cell cycle arrest independently of the spindle assembly checkpoint (SAC), suggesting that while SAC protects mitotic accuracy by slowing down mitosis, 53BP1 and USP28 function in parallel to select against disturbed or delayed mitosis, promoting mitotic efficiency. DOI: http://dx.doi.org/10.7554/eLife.16270.001 PMID:27371829

  3. Proteotoxic stress induces a cell-cycle arrest by stimulating Lon to degrade the replication initiator DnaA.

    PubMed

    Jonas, Kristina; Liu, Jing; Chien, Peter; Laub, Michael T

    2013-08-01

    The decision to initiate DNA replication is a critical step in the cell cycle of all organisms. Cells often delay replication in the face of stressful conditions, but the underlying mechanisms remain incompletely defined. Here, we demonstrate in Caulobacter crescentus that proteotoxic stress induces a cell-cycle arrest by triggering the degradation of DnaA, the conserved replication initiator. A depletion of available Hsp70 chaperone, DnaK, either through genetic manipulation or heat shock, induces synthesis of the Lon protease, which can directly degrade DnaA. Unexpectedly, we find that unfolded proteins, which accumulate following a loss of DnaK, also allosterically activate Lon to degrade DnaA, thereby ensuring a cell-cycle arrest. Our work reveals a mechanism for regulating DNA replication under adverse growth conditions. Additionally, our data indicate that unfolded proteins can actively and directly alter substrate recognition by cellular proteases. PMID:23911325

  4. TCH-1030 targeting on topoisomerase I induces S-phase arrest, DNA fragmentation, and cell death of breast cancer cells.

    PubMed

    Liu, Yu-Peng; Chen, Hui-Ling; Tzeng, Cherng-Chyi; Lu, Pei-Jung; Lo, Cheng-Wei; Lee, Yu-Cheng; Tseng, Chih-Hua; Chen, Yeh-Long; Yang, Chia-Ning

    2013-04-01

    Camptothecin (CPT) and its derivatives are powerful anticancer agents, but these compounds are chemically unstable due to their α-hydroxy lactone six-membered E-ring structure, which is essential for trapping topoisomerase I (topo I)-DNA cleavage complexes. Moreover, the reversibility of trapping the topo I-DNA cleavage complex and the tight binding of CPTs to human serum albumin limit the levels of available active drug. CPT analogs are the only clinically available drugs that target topo I. Owing to the clinical importance of CPT analogs, the development of new anticancer agents which inhibit topo I is urgently needed. In the present study, we report the synthesis, biologic evaluation, and molecular mechanism of a series of substituted indeno[1,2-c]quinoline derivatives against the growth of several human cancer cell lines. We found that 9-methoxy-6-(piperazin-1-yl)-11H-indeno[1,2-c]quinoline-11-one O-3-(dimethylamino)propyl oxime (TCH-1030) intercalated into DNA and preferentially inhibited DNA topo I relaxation. Flow cytometric analysis and BrdU incorporation assays indicate that TCH-1030 alters cell cycle progression, induces S-phase arrest, and causes DNA polyploidy (>4 N) that is distinct from the typical G2-M arrest reported with known topoisomerase toxins. Our data indicate that TCH-1030 induces caspase 3 activation, PARP cleavage, γ-H2AX phosphorylation, and, consequently, DNA fragmentation and apoptosis. We also demonstrated that treatment with TCH-1030 significantly inhibits tumor growth in a BT483-xenograft nude mouse model. Taken together, we conclude that the primary mechanism of action of TCH-1030-induced cell cycle retardation and apoptosis-mediated DNA damage involves DNA binding and intercalation as well as topo I inhibition. PMID:23430225

  5. Solanum tuberosum lectin inhibits Ehrlich ascites carcinoma cells growth by inducing apoptosis and G2/M cell cycle arrest.

    PubMed

    Kabir, Syed Rashel; Rahman, Md Musfikur; Amin, Ruhul; Karim, Md Rezaul; Mahmud, Zahid Hayat; Hossain, M Tofazzal

    2016-06-01

    Recently, a lectin was purified from the potato cultivated in Bangladesh locally known as Sheel. In the present study cytotoxicity of the lectin against Ehrlich ascites carcinoma (EAC) cells was studied by MTT assay in vitro in RPMI-1640 medium and 8.0-36.0 % cell growth inhibition was observed at the range of 2.5-160 μg/ml protein concentration when incubated for 24 h. The lectin-induced apoptosis in EAC cells was confirmed by fluorescence and optical microscope. The apoptotic cell death was also confirmed by using caspase inhibitors. Cells growth inhibition caused by the lectin (36 %) was remarkably decreased to 7.6 and 22.3 % respectively in the presence of caspase-3 and -8 inhibitors. RT-PCR was used to evaluate the expression of apoptosis-related genes Bcl-X, p53, and Bax. An intensive expression of Bcl-X gene was observed in untreated control EAC cells with the disappeared of the gene in Sheel-treated EAC cells. At the same time, Bax gene expression appeared only in Sheel-treated EAC cells and the expression level of the p53 gene was increased remarkable after the treatment of EAC cells with the lectin. The lectin showed strong agglutination activity against EAC cells. Flow cytometry was used to study the cell cycle phases of EAC cells and it was observed that the lectin arrested the G2/M phase. In conclusion, Sheel lectin inhibited EAC cells growth by inducing apoptosis. PMID:26733170

  6. Human cytochrome c enters murine J774 cells and causes G{sub 1} and G{sub 2}/M cell cycle arrest and induction of apoptosis

    SciTech Connect

    Hiraoka, Yoshinori; Granja, Ana Teresa; Fialho, Arsenio M.; Schlarb-Ridley, Beatrix G.; Das Gupta, Tapas K.; Chakrabarty, Ananda M.; Yamada, Tohru . E-mail: tohru@uic.edu

    2005-12-16

    Cytochrome c is well known as a carrier of electrons during respiration. Current evidence indicates that cytochrome c also functions as a major component of apoptosomes to induce apoptosis in eukaryotic cells as well as an antioxidant. More recently, a prokaryotic cytochrome c, cytochrome c {sub 551} from Pseudomonas aeruginosa, has been shown to enter in mammalian cells such as the murine macrophage-like J774 cells and causes inhibition of cell cycle progression. Much less is known about such functions by mammalian cytochromes c, particularly the human cytochrome c. We now report that similar to P. aeruginosa cytochrome c {sub 551}, the purified human cytochrome c protein can enter J774 cells and induce cell cycle arrest at the G{sub 1} to S phase, as well as at the G{sub 2}/M phase at higher concentrations. Unlike P. aeruginosa cytochrome c {sub 551} which had no effect on the induction of apoptosis, human cytochrome c induces significant apoptosis and cell death in J774 cells, presumably through inhibition of the cell cycle at the G{sub 2}/M phase. When incubated with human breast cancer MCF-7 and normal mammary epithelial cell line MCF-10A1 cells, human cytochrome c entered in both types of cells but induced cell death only in the normal MCF-10A1 cells. The ability of human cytochrome c to enter J774 cells was greatly reduced at 4 deg. C, suggesting energy requirement in the entry process.

  7. Septins Regulate Actin Organization and Cell Cycle Arrest Through SOCS7-Mediated Nuclear Accumulation of NCK

    PubMed Central

    Kremer, Brandon E.; Adang, Laura A.; Macara, Ian G.

    2007-01-01

    SUMMARY Mammalian septins are GTP-binding proteins the functions of which are not well understood. Knockdown of Sept2, 6, and 7 causes stress fibers to disintegrate and the cells to lose polarity. We now show that this phenotype is induced by nuclear accumulation of the adapter protein NCK, as the effects can be reversed or induced by cytoplasmic or nuclear NCK, respectively. NCK is carried into the nucleus by SOCS7 (Suppressor Of Cytokine Signaling-7), which contains nuclear import/export signals. SOCS7 interacts through distinct domains with septins and NCK. DNA damage induces actin and septin rearrangement and rapid nuclear accumulation of NCK and SOCS7. Moreover, NCK expression is essential for cell-cycle arrest. The septin-SOCS7-NCK axis intersects with the canonical DNA damage cascade downstream of ATM/ATR and is essential for p53 Ser15 phosphorylation. These data illuminate an unanticipated connection between septins, SOCS7, NCK signaling, and the DNA damage response. PMID:17803907

  8. Severe NDE1-mediated microcephaly results from neural progenitor cell cycle arrests at multiple specific stages.

    PubMed

    Doobin, David J; Kemal, Shahrnaz; Dantas, Tiago J; Vallee, Richard B

    2016-01-01

    Microcephaly is a cortical malformation disorder characterized by an abnormally small brain. Recent studies have revealed severe cases of microcephaly resulting from human mutations in the NDE1 gene, which is involved in the regulation of cytoplasmic dynein. Here using in utero electroporation of NDE1 short hairpin RNA (shRNA) in embryonic rat brains, we observe cell cycle arrest of proliferating neural progenitors at three distinct stages: during apical interkinetic nuclear migration, at the G2-to-M transition and in regulation of primary cilia at the G1-to-S transition. RNAi against the NDE1 paralogue NDEL1 has no such effects. However, NDEL1 overexpression can functionally compensate for NDE1, except at the G2-to-M transition, revealing a unique NDE1 role. In contrast, NDE1 and NDEL1 RNAi have comparable effects on postmitotic neuronal migration. These results reveal that the severity of NDE1-associated microcephaly results not from defects in mitosis, but rather the inability of neural progenitors to ever reach this stage. PMID:27553190

  9. Severe NDE1-mediated microcephaly results from neural progenitor cell cycle arrests at multiple specific stages

    PubMed Central

    Doobin, David J.; Kemal, Shahrnaz; Dantas, Tiago J.; Vallee, Richard B.

    2016-01-01

    Microcephaly is a cortical malformation disorder characterized by an abnormally small brain. Recent studies have revealed severe cases of microcephaly resulting from human mutations in the NDE1 gene, which is involved in the regulation of cytoplasmic dynein. Here using in utero electroporation of NDE1 short hairpin RNA (shRNA) in embryonic rat brains, we observe cell cycle arrest of proliferating neural progenitors at three distinct stages: during apical interkinetic nuclear migration, at the G2-to-M transition and in regulation of primary cilia at the G1-to-S transition. RNAi against the NDE1 paralogue NDEL1 has no such effects. However, NDEL1 overexpression can functionally compensate for NDE1, except at the G2-to-M transition, revealing a unique NDE1 role. In contrast, NDE1 and NDEL1 RNAi have comparable effects on postmitotic neuronal migration. These results reveal that the severity of NDE1-associated microcephaly results not from defects in mitosis, but rather the inability of neural progenitors to ever reach this stage. PMID:27553190

  10. Knocking down nucleolin expression in gliomas inhibits tumor growth and induces cell cycle arrest.

    PubMed

    Xu, Zhiqiang; Joshi, Neel; Agarwal, Ashima; Dahiya, Sonika; Bittner, Patrice; Smith, Erin; Taylor, Sara; Piwnica-Worms, David; Weber, Jason; Leonard, Jeffrey R

    2012-05-01

    Nucleolin is a multifunctional protein whose expression often correlates with increased cellular proliferation. While the expression of nucleolin is often elevated in numerous cancers, its expression in normal human brain and in astrocytomas has not been previously reported. Using paraffin-embedded sections from normal adult autopsy specimens and glioma resection specimens, we demonstrate that nucleolin expression is limited in the normal human brain specifically to mature neurons, ependymal cells, and granular cells of the dentate gyrus. While astrocytes in the normal human brain do not express nucleolin at significant levels, glioblastoma cell lines and primary human astrocytoma cells exhibit considerable nucleolin expression. Reduction of nucleolin expression through siRNA-mediated knockdown in the U87MG glioblastoma cell line caused a dramatic decrease in cell proliferation and induced cell cycle arrest in vitro. Moreover, conditional siRNA knockdown of nucleolin expression in U87MG intracranial xenografts in nude mice caused dramatic reduction in tumor size. Taken together, these results implicate nucleolin in the regulation of human astrocytoma proliferation in vitro and tumorigenicity in vivo and suggest that nucleolin may represent a potential novel therapeutic target for astrocytomas. PMID:22382782

  11. Unprecedented inhibition of tubulin polymerization directed by gold nanoparticles inducing cell cycle arrest and apoptosis

    NASA Astrophysics Data System (ADS)

    Choudhury, Diptiman; Xavier, Paulrajpillai Lourdu; Chaudhari, Kamalesh; John, Robin; Dasgupta, Anjan Kumar; Pradeep, Thalappil; Chakrabarti, Gopal

    2013-05-01

    The effect of gold nanoparticles (AuNPs) on the polymerization of tubulin has not been examined till now. We report that interaction of weakly protected AuNPs with microtubules (MTs) could cause inhibition of polymerization and aggregation in the cell free system. We estimate that single citrate capped AuNPs could cause aggregation of ~105 tubulin heterodimers. Investigation of the nature of inhibition of polymerization and aggregation by Raman and Fourier transform-infrared (FTIR) spectroscopies indicated partial conformational changes of tubulin and microtubules, thus revealing that AuNP-induced conformational change is the driving force behind the observed phenomenon. Cell culture experiments were carried out to check whether this can happen inside a cell. Dark field microscopy (DFM) combined with hyperspectral imaging (HSI) along with flow cytometric (FC) and confocal laser scanning microscopic (CLSM) analyses suggested that AuNPs entered the cell, caused aggregation of the MTs of A549 cells, leading to cell cycle arrest at the G0/G1 phase and concomitant apoptosis. Further, Western blot analysis indicated the upregulation of mitochondrial apoptosis proteins such as Bax and p53, down regulation of Bcl-2 and cleavage of poly(ADP-ribose) polymerase (PARP) confirming mitochondrial apoptosis. Western blot run after cold-depolymerization revealed an increase in the aggregated insoluble intracellular tubulin while the control and actin did not aggregate, suggesting microtubule damage induced cell cycle arrest and apoptosis. The observed polymerization inhibition and cytotoxic effects were dependent on the size and concentration of the AuNPs used and also on the incubation time. As microtubules are important cellular structures and target for anti-cancer drugs, this first observation of nanoparticles-induced protein's conformational change-based aggregation of the tubulin-MT system is of high importance, and would be useful in the understanding of cancer therapeutics

  12. Inactivation of nucleolin leads to nucleolar disruption, cell cycle arrest and defects in centrosome duplication

    PubMed Central

    Ugrinova, Iva; Monier, Karine; Ivaldi, Corinne; Thiry, Marc; Storck, Sébastien; Mongelard, Fabien; Bouvet, Philippe

    2007-01-01

    Background Nucleolin is a major component of the nucleolus, but is also found in other cell compartments. This protein is involved in various aspects of ribosome biogenesis from transcription regulation to the assembly of pre-ribosomal particles; however, many reports suggest that it could also play an important role in non nucleolar functions. To explore nucleolin function in cell proliferation and cell cycle regulation we used siRNA to down regulate the expression of nucleolin. Results We found that, in addition to the expected effects on pre-ribosomal RNA accumulation and nucleolar structure, the absence of nucleolin results in a cell growth arrest, accumulation in G2, and an increase of apoptosis. Numerous nuclear alterations, including the presence of micronuclei, multiple nuclei or large nuclei are also observed. In addition, a large number of mitotic cells showed a defect in the control of centrosome duplication, as indicated by the presence of more than 2 centrosomes per cell associated with a multipolar spindle structure in the absence of nucleolin. This phenotype is very similar to that obtained with the inactivation of another nucleolar protein, B23. Conclusion Our findings uncovered a new role for nucleolin in cell division, and highlight the importance of nucleolar proteins for centrosome duplication. PMID:17692122

  13. Fangchinoline induces G1 arrest in breast cancer cells through cell-cycle regulation.

    PubMed

    Xing, Zhibo; Zhang, Youxue; Zhang, Xianyu; Yang, Yanmei; Ma, Yuyan; Pang, Da

    2013-12-01

    Fangchinoline, an alkaloid derived from the dry roots of Stephaniae tetrandrine S. Moore (Menispermaceae), has been shown to possess cytotoxic, anti-inflammatory, and antioxidant properties. In this study, we used Fangchinoline to inhibit breast cancer cell proliferation and to investigate its underlying molecular mechanisms. Human breast cancer cell lines, MCF-7 and MDA-MB-231, were both used in this study. We found that Fangchinoline significantly decreased cell proliferation in a dose-dependent manner and induced G1-phase arrest in both cell lines. In addition, upon analysis of expression of cell cycle-related proteins, we found that Fangchinoline reduced expression of cyclin D1, cyclin D3, and cyclin E, and increased expression of the cyclin-dependent kinase (CDK) inhibitors, p21/WAF1, and p27/KIP1. Moreover, Fangchinoline also inhibited the kinase activities of CDK2, CDK4, and CDK6. These results suggest that Fangchinoline can inhibit human breast cancer cell proliferation and thus may have potential applications in cancer therapy. PMID:23401195

  14. Oxidative stress, apoptosis, and cell cycle arrest are induced in primary fetal alveolar type II epithelial cells exposed to fine particulate matter from cooking oil fumes.

    PubMed

    Liu, Ying; Chen, Yan-Yan; Cao, Ji-Yu; Tao, Fang-Biao; Zhu, Xiao-Xia; Yao, Ci-Jiang; Chen, Dao-Jun; Che, Zhen; Zhao, Qi-Hong; Wen, Long-Ping

    2015-07-01

    Epidemiological studies demonstrate a linkage between morbidity and mortality and particulate matter (PM), particularly fine particulate matter (PM2.5) that can readily penetrate into the lungs and are therefore more likely to increase the incidence of respiratory and cardiovascular diseases. The present study investigated the compositions of cooking oil fume (COF)-derived PM2.5, which is the major source of indoor pollution in China. Furthermore, oxidative stress, cytotoxicity, apoptosis, and cell cycle arrest induced by COF-derived PM2.5 in primary fetal alveolar type II epithelial cells (AEC II cells) were also detected. N-acetyl-L-cysteine (NAC), a radical scavenger, was used to identify the role of oxidative stress in the abovementioned processes. Our results suggested that compositions of COF-derived PM2.5 are obviously different to PM2.5 derived from other sources, and COF-derived PM2.5 led to cell death, oxidative stress, apoptosis, and G0/G1 cell arrest in primary fetal AEC II cells. Furthermore, the results also showed that COF-derived PM2.5 induced apoptosis through the endoplasmic reticulum (ER) stress pathway, which is indicated by the increased expression of ER stress-related apoptotic markers, namely GRP78 and caspase-12. Besides, the induction of oxidative stress, cytotoxicity, apoptosis, and cell cycle arrest was reversed by pretreatment with NAC. These findings strongly suggested that COF-derived PM2.5-induced toxicity in primary fetal AEC II cells is mediated by increased oxidative stress, accompanied by ER stress which results in apoptosis. PMID:25634364

  15. Arecoline induced cell cycle arrest, apoptosis, and cytotoxicity to human endothelial cells.

    PubMed

    Tseng, Shuei-Kuen; Chang, Mei-Chi; Su, Cheng-Yao; Chi, Lin-Yang; Chang, Jenny Zwei-Ching; Tseng, Wan-Yu; Yeung, Sin-Yuet; Hsu, Ming-Lun; Jeng, Jiiang-Huei

    2012-08-01

    Betel quid (BQ) chewing is a common oral habit in South Asia and Taiwan. BQ consumption may increase the risk of oral squamous cell carcinoma (OSCC), oral submucous fibrosis (OSF), and periodontitis as well as systemic diseases (atherosclerosis, hypertension, etc.). However, little is known about the toxic effect of BQ components on endothelial cells that play important roles for angiogenesis, carcinogenesis, tissue fibrosis, and cardiovascular diseases. EAhy 926 (EAHY) endothelial cells were exposed to arecoline, a major BQ alkaloid, for various time periods. Cytotoxicity was estimated by 3-(4, 5- dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assay. The cell cycle distribution of EAHY cells residing in sub-G0/G1, G0/G1, S-, and G2/M phases was analyzed by propidium iodide staining of cellular DNA content and flow cytometry. Some EAHY cells retracted, became round-shaped in appearance, and even detached from the culture plate after exposure to higher concentrations of arecoline (> 0.4 mM). At concentrations of 0.4 and 0.8 mM, arecoline induced significant cytotoxicity to EAHY cells. At similar concentrations, arecoline induced G2/M cell cycle arrest and increased sub-G0/G1 population, a hallmark of apoptosis. Interestingly, prolonged exposure to arecoline (0.1 mM) for 12 and 21 days significantly suppressed the proliferation of EAHY cells, whereas EAHY cells showed adaptation and survived when exposed to 0.05 mM arecoline. These results suggest that BQ components may contribute to the pathogenesis of OSF and BQ chewing-related cardiovascular diseases via toxicity to oral or systemic endothelial cells, leading to impairment of vascular function. During BQ chewing, endothelial damage may be induced by areca nut components and associate with the pathogenesis of OSF, periodontitis, and cardiovascular diseases. PMID:21847594

  16. 6-Shogaol induces cell cycle arrest and apoptosis in human hepatoma cells through pleiotropic mechanisms.

    PubMed

    Wu, Jung-Ju; Omar, Hany A; Lee, Ying-Ray; Teng, Yen-Ni; Chen, Pin-Shern; Chen, Yu-Chung; Huang, Hsiao-Shan; Lee, Kuan-Han; Hung, Jui-Hsiang

    2015-09-01

    Shogaols are a group of the active constituents of ginger that have been identified to have various biological activities. The aim of the current study was to investigate the antitumor activity of 6-shogaol in hepatocellular carcinoma (HCC) and the possible involvement of reactive oxygen species as a putative mechanism of action. HCC cell lines, HepG2 and Huh-7, were used to study the in vitro anti-cancer activity of 6-shogaol via the application of various molecular biology techniques. Results showed that 6-shogaol effectively inhibited the cell viability, caused cell cycle arrest at G2/M phase and induced apoptosis in HCC cells as indicated by MTT assay, DAPI nuclear staining, annexin V assay, cell cycle analysis, and activation of caspase-3. Western blot analysis revealed the ability of 6-shogaol to target cancer survival signaling pathways mediated by mitogen-activated protein kinase (MAPK), 5' AMP-activated protein kinase (AMPK) and Akt. In addition, 6-Shogaol induced alteration of cyclin proteins expression and caused cleavage of protein kinase C delta. Furthermore, 6-Shogaol was able to induce the production of reactive oxygen species and endoplasmic reticulum (ER) stress-associated proteins and the consequent activation of autophagy in HepG2 cells. Taken together, the current study highlights evidences that 6-shogaol induces apoptosis, modulates cyclins expression and targets cancer survival signaling pathways in HCC cell lines, at least in part, via the production of reactive oxygen species. These findings support 6-shogaol's clinical promise as a potential candidate for HCC therapy. PMID:26101062

  17. Inhibition of the proteasome induces cell cycle arrest and apoptosis in mantle cell lymphoma cells.

    PubMed

    Bogner, Christian; Ringshausen, Ingo; Schneller, Folker; Fend, Falko; Quintanilla-Martinez, Leticia; Häcker, Georg; Goetze, Katharina; Oostendorp, Robert; Peschel, Christian; Decker, Thomas

    2003-07-01

    Mantle cell lymphoma (MCL) is a distinctive non-Hodgkin's lymphoma subtype, characterized by overexpression of cyclin D1 as a consequence of the chromosomal translocation t(11;14)(q13;q32). MCL remains an incurable disease, combining the unfavourable clinical features of aggressive and indolent lymphomas. The blastic variant of MCL, which is often associated with additional cytogenetic alterations, has an even worse prognosis and new treatment options are clearly needed. The present study investigated the effect of a specific proteasome inhibitor, lactacystin, on cell cycle progression and apoptosis in two lymphoma cell lines harbouring the t(11;14)(q13;q32) and additional cytogenetic alterations, including p53 mutation (NCEB) and p16 deletion (Granta 519). Granta cells were more susceptible to inhibition of the proteasome with respect to inhibition of proliferation and apoptosis induction. No changes were observed in the expression levels of the G1 regulatory molecules cyclin D1 and cdk4, but cell cycle arrest and apoptosis induction was accompanied by accumulation of the cdk inhibitor p21 in both cell lines. Increased p53 expression was only observed in Granta cells with wild-type p53. Cleavage of procaspase-3 and -9 was observed but cleavage of procaspase-8 was not involved in apoptosis induction. The proapoptotic effect of lactacystin was reversed by pretreatment with the pancaspase inhibitor zVAD.fmk. Lactacystin was also effective in inducing apoptosis in lymphoma cells from MCL patients. We conclude that inhibition of the proteasome might be a promising therapeutic approach for this incurable disease. PMID:12846895

  18. T. gondii RP Promoters & Knockdown Reveal Molecular Pathways Associated with Proliferation and Cell-Cycle Arrest

    PubMed Central

    Hutson, Samuel L.; Mui, Ernest; Kinsley, Karen; Witola, William H.; Behnke, Michael S.; El Bissati, Kamal; Muench, Stephen P.; Rohrman, Brittany; Liu, Susan R.; Wollmann, Robert; Ogata, Yuko; Sarkeshik, Ali; Yates, John R.; McLeod, Rima

    2010-01-01

    Molecular pathways regulating rapid proliferation and persistence are fundamental for pathogens but are not elucidated fully in Toxoplasma gondii. Promoters of T. gondii ribosomal proteins (RPs) were analyzed by EMSAs and ChIP. One RP promoter domain, known to bind an Apetela 2, bound to nuclear extract proteins. Promoter domains appeared to associate with histone acetyl transferases. To study effects of a RP gene's regulation in T. gondii, mutant parasites (Δrps13) were engineered with integration of tetracycline repressor (TetR) response elements in a critical location in the rps13 promoter and transfection of a yellow fluorescent-tetracycline repressor (YFP-TetR). This permitted conditional knockdown of rps13 expression in a tightly regulated manner. Δrps13 parasites were studied in the presence (+ATc) or absence of anhydrotetracycline (-ATc) in culture. -ATc, transcription of the rps13 gene and expression of RPS13 protein were markedly diminished, with concomitant cessation of parasite replication. Study of Δrps13 expressing Myc-tagged RPL22, -ATc, showed RPL22 diminished but at a slower rate. Quantitation of RNA showed diminution of 18S RNA. Depletion of RPS13 caused arrest of parasites in the G1 cell cycle phase, thereby stopping parasite proliferation. Transcriptional differences ±ATc implicate molecules likely to function in regulation of these processes. In vitro, -ATc, Δrps13 persists for months and the proliferation phenotype can be rescued with ATc. In vivo, however, Δrps13 could only be rescued when ATc was given simultaneously and not at any time after 1 week, even when L-NAME and ATc were administered. Immunization with Δrps13 parasites protects mice completely against subsequent challenge with wildtype clonal Type 1 parasites, and robustly protects mice against wildtype clonal Type 2 parasites. Our results demonstrate that G1 arrest by ribosomal protein depletion is associated with persistence of T. gondii in a model system in vitro and

  19. p21 binding to PCNA causes G1 and G2 cell cycle arrest in p53-deficient cells.

    PubMed

    Cayrol, C; Knibiehler, M; Ducommun, B

    1998-01-22

    A unique feature of p21 that distinguishes it from the other cyclin-dependent kinase (CDK) inhibitors is its ability to associate with the proliferating cell nuclear antigen (PCNA), an auxiliary factor for DNA polymerases delta and epsilon. While it is now well established that inhibition of cyclin/CDK complexes by p21 can result in G1 cell cycle arrest, the consequences of p21/PCNA interaction on cell cycle progression have not yet been determined. Here, we show, using a tetracycline-regulated system, that expression of wild-type p21 in p53-deficient DLD1 human colon cancer cells inhibits DNA synthesis and causes G1 and G2 cell cycle arrest. Similar effects are observed in cells expressing p21CDK-, a mutant impaired in the interaction with CDKs, but not in cells expressing p21PCNA-, a mutant deficient for the interaction with PCNA. Analysis of cells treated with a p21-derived PCNA-binding peptide provides additional evidence that the growth inhibitory effects of p21 and p21CDK result from their ability to bind to PCNA. Our results suggest that p21 might inhibit cell cycle progression by two independent mechanisms, inhibition of cyclin/CDK complexes, and inhibition of PCNA function resulting in both G1 and G2 arrest. PMID:9467956

  20. Aloe emodin induces G2/M cell cycle arrest and apoptosis via activation of caspase-6 in human colon cancer cells.

    PubMed

    Suboj, Priya; Babykutty, Suboj; Srinivas, Priya; Gopala, Srinivas

    2012-01-01

    Aloe emodin (AE), a natural anthraquinone, is reported to have antiproliferative activity in various cancer cell lines. In this study, we analyzed the molecular mechanisms involved in the growth-inhibitory activity of this hydroxyanthraquinone in colon cancer cell, WiDr. In our observation AE inhibited cell proliferation by arresting the cell cycle at the G2/M phase and inhibiting cyclin B1. AE appreciably induced cell death specifically through the induction of apoptosis and by activating caspases 9/6. Apoptotic execution was found to be solely dependent on caspase-6 rather than caspase-3 or caspase-7. This is the first study indicating that the AE induces apoptosis specifically through the activation of caspase-6. PMID:22343391

  1. Cell cycle regulation and apoptotic cell death in experimental colon carcinogenesis: intervening with cyclooxygenase-2 inhibitors.

    PubMed

    Saini, Manpreet Kaur; Sanyal, Sankar Nath

    2015-01-01

    Relative imbalance in the pathways regulating cell cycle, cell proliferation, or cell death marks a prerequisite for neoplasm. C-phycocyanin, a biliprotein from Spirulina platensis and a selective COX-2 inhibitor along with piroxicam, a traditional nonsteroidal antiinflammatory drug was used to investigate the role of cell cycle regulatory proteins and proinflammatory transcription factor NFκB in 1,2-dimethylhydrazine dihydrochloride (DMH)-induced rat colon carcinogenesis. Cell cycle regulators [cyclin D1, cyclin E, cyclin dependent kinase 2 (CDK2), CDK4, and p53], NFκB (p65) pathway, and proliferating cell nuclear antigen (PCNA) were evaluated by gene and protein expression, whereas apoptosis was studied by terminal deoxynucleotidyl transferase dUTP nick end labeling and apoptotic bleb assay. Molecular docking of ligand protein interaction was done to validate the in vivo results. Cyclin D1, cyclin E, CDK2, and CDK4 were overexpressed in DMH, whereas piroxicam and c-phycocyanin promoted the cell cycle arrest by downregulating them. Both drugs mediated apoptosis through p53 activation. Piroxicam and c-phycocyanin also stimulated antiproliferation by restraining PCNA expression and reduced cell survival via inhibiting NFκB (p65) pathway. Molecular docking revealed that phycocyanobilin (a chromophore of c-phycocyanin) interact with DNA binding site of NFκB. Inhibition of cyclin/CDK complex by piroxicam and c-phycocyanin affects the expression of p53 in colon cancer followed by downregulation of NFκB and PCNA levels, thus substantiating the antineoplastic role of these agents. PMID:25825916

  2. Polychlorinated Biphenyl Quinone Metabolite Promotes p53-Dependent DNA Damage Checkpoint Activation, S-Phase Cycle Arrest and Extrinsic Apoptosis in Human Liver Hepatocellular Carcinoma HepG2 Cells.

    PubMed

    Song, Xiufang; Li, Lingrui; Shi, Qiong; Lehmler, Hans-Joachim; Fu, Juanli; Su, Chuanyang; Xia, Xiaomin; Song, Erqun; Song, Yang

    2015-11-16

    Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants. The toxic behavior and mechanism of PCBs individuals and congeners have been extensively investigated. However, there is only limited information on their metabolites. Our previous studies have shown that a synthetic PCB metabolite, PCB29-pQ, causes oxidative damage with the evidence of cytotoxicity, genotoxicity, and mitochondrial-derived intrinsic apoptosis. Here, we investigate the effects of PCB29-pQ on DNA damage checkpoint activation, cell cycle arrest, and death receptor-related extrinsic apoptosis in human liver hepatocellular carcinoma HepG2 cells. Our results illustrate that PCB29-pQ increases the S-phase cell population by down-regulating cyclins A/D1/E, cyclin-dependent kinases (CDK 2/4/6), and cell division cycle 25A (CDC25A) and up-regulating p21/p27 protein expressions. PCB29-pQ also induces apoptosis via the up-regulation of Fas/FasL and the activation of caspase 8/3. Moreover, p53 plays a pivotal role in PCB29-pQ-induced cell cycle arrest and apoptosis via the activation of ATM/Chk2 and ATR/Chk1 checkpoints. Cell cycle arrest and apoptotic cell death were attenuated by the pretreatment with antioxidant N-acetyl-cysteine (NAC). Taken together, these results demonstrate that PCB29-pQ induces oxidative stress and promotes p53-dependent DNA damage checkpoint activation, S-phase cycle arrest, and extrinsic apoptosis in HepG2 cells. PMID:26451628

  3. Impact of Mitochondria-Mediated Apoptosis in U251 Cell Cycle Arrest in G1 Stage and Caspase Activation

    PubMed Central

    Zhang, Lei; Liang, Peng; Zhang, Rui

    2015-01-01

    Background Most mitochondria-mediated apoptosis has some relevance to the cell cycle, but there is still a lack of investigations about U251 cell cycle in human brain glioma cells. In this study, we aimed to clarify the correlation of mitochondria-mediated apoptosis with the U251 cell cycle and its influence on apoptosis, through observing the impact of mitochondria-mediated apoptosis in U251cell specificity cycle arrest and Caspase activation. Material/Methods AnnexinV/PI and API were used to label the brain glioma cells for flow cytometry analysis of U251 cell apoptosis and cell cycle. RT-PCR and Western blot were performed to detect Caspase-3 and Caspase-9 activation. Results Peripheral blood in stationary phase is not sensitive to apoptosis induction, but U251 cells have obvious apoptosis. Mitochondria-mediated apoptosis mainly occurs in the G1 phase of the cell cycle. Caspase-3 and Caspase-9 mRNAs and proteins expression increased significantly after the cells were treated by mitochondrial apoptosis-related gene Bax induction. Conclusions Mitochondria-mediated apoptosis is related to the U251 cell cycle with specific G1 stage arrest. Caspase activation occurs in the process of cell apoptosis. PMID:26594875

  4. Conditional inactivation of PDCD2 induces p53 activation and cell cycle arrest.

    PubMed

    Granier, Celine J; Wang, Wei; Tsang, Tiffany; Steward, Ruth; Sabaawy, Hatem E; Bhaumik, Mantu; Rabson, Arnold B

    2014-01-01

    PDCD2 (programmed cell death domain 2) is a highly conserved, zinc finger MYND domain-containing protein essential for normal development in the fly, zebrafish and mouse. The molecular functions and cellular activities of PDCD2 remain unclear. In order to better understand the functions of PDCD2 in mammalian development, we have examined PDCD2 activity in mouse blastocyst embryos, as well as in mouse embryonic stem cells (ESCs) and embryonic fibroblasts (MEFs). We have studied mice bearing a targeted PDCD2 locus functioning as a null allele through a splicing gene trap, or as a conditional knockout, by deletion of exon2 containing the MYND domain. Tamoxifen-induced knockout of PDCD2 in MEFs, as well as in ESCs, leads to defects in progression from the G1 to the S phase of cell cycle, associated with increased levels of p53 protein and p53 target genes. G1 prolongation in ESCs was not associated with induction of differentiation. Loss of entry into S phase of the cell cycle and marked induction of nuclear p53 were also observed in PDCD2 knockout blastocysts. These results demonstrate a unique role for PDCD2 in regulating the cell cycle and p53 activation during early embryonic development of the mouse. PMID:25150276

  5. Conditional inactivation of PDCD2 induces p53 activation and cell cycle arrest

    PubMed Central

    Granier, Celine J.; Wang, Wei; Tsang, Tiffany; Steward, Ruth; Sabaawy, Hatem E.; Bhaumik, Mantu; Rabson, Arnold B.

    2014-01-01

    ABSTRACT PDCD2 (programmed cell death domain 2) is a highly conserved, zinc finger MYND domain-containing protein essential for normal development in the fly, zebrafish and mouse. The molecular functions and cellular activities of PDCD2 remain unclear. In order to better understand the functions of PDCD2 in mammalian development, we have examined PDCD2 activity in mouse blastocyst embryos, as well as in mouse embryonic stem cells (ESCs) and embryonic fibroblasts (MEFs). We have studied mice bearing a targeted PDCD2 locus functioning as a null allele through a splicing gene trap, or as a conditional knockout, by deletion of exon2 containing the MYND domain. Tamoxifen-induced knockout of PDCD2 in MEFs, as well as in ESCs, leads to defects in progression from the G1 to the S phase of cell cycle, associated with increased levels of p53 protein and p53 target genes. G1 prolongation in ESCs was not associated with induction of differentiation. Loss of entry into S phase of the cell cycle and marked induction of nuclear p53 were also observed in PDCD2 knockout blastocysts. These results demonstrate a unique role for PDCD2 in regulating the cell cycle and p53 activation during early embryonic development of the mouse. PMID:25150276

  6. A novel peptide sansalvamide analogue inhibits pancreatic cancer cell growth through G0/G1 cell-cycle arrest

    SciTech Connect

    Ujiki, Michael B. |; Milam, Ben; Ding Xianzhong |; Roginsky, Alexandra B.; Salabat, M. Reza; Talamonti, Mark S.; Bell, Richard H. |; Gu Wenxin; Silverman, Richard B. ||; Adrian, Thomas E. |. E-mail: tadrian@northwestern.edu

    2006-02-24

    Patients with pancreatic cancer have little hope for cure because no effective therapies are available. Sansalvamide A is a cyclic depsipeptide produced by a marine fungus. We investigated the effect of a novel sansalvamide A analogue on growth, cell-cycle phases, and induction of apoptosis in human pancreatic cancer cells in vitro. The sansalvamide analogue caused marked time- and concentration-dependent inhibition of DNA synthesis and cell proliferation of two human pancreatic cancer cell lines (AsPC-1 and S2-013). The analogue induced G0/G1 phase cell-cycle arrest and morphological changes suggesting induction of apoptosis. Apoptosis was confirmed by annexin V binding. This novel sansalvamide analogue inhibits growth of pancreatic cancer cells through G0/G1 arrest and induces apoptosis. Sansalvamide analogues may be valuable for the treatment of pancreatic cancer.

  7. Inhibition of protein kinase B activity induces cell cycle arrest and apoptosis during early G₁ phase in CHO cells.

    PubMed

    van Opstal, Angélique; Bijvelt, José; van Donselaar, Elly; Humbel, Bruno M; Boonstra, Johannes

    2012-04-01

    Inhibition of PKB (protein kinase B) activity using a highly selective PKB inhibitor resulted in inhibition of cell cycle progression only if cells were in early G1 phase at the time of addition of the inhibitor, as demonstrated by time-lapse cinematography. Addition of the inhibitor during mitosis up to 2 h after mitosis resulted in arrest of the cells in early G1 phase, as deduced from the expression of cyclins D and A and incorporation of thymidine. After 24 h of cell cycle arrest, cells expressed the cleaved caspase-3, a central mediator of apoptosis. These results demonstrate that PKB activity in early G1 phase is required to prevent the induction of apoptosis. Using antibodies, it was demonstrated that active PKB translocates to the nucleus during early G1 phase, while an even distribution of PKB was observed through cytoplasm and nucleus during the end of G1 phase. PMID:22251027

  8. Serotonin and sudden death: differential effects of serotonergic drugs on seizure-induced respiratory arrest in DBA/1 mice.

    PubMed

    Faingold, Carl L; Kommajosyula, Srinivasa P; Long, X; Plath, Kristin; Randall, Marcus

    2014-08-01

    In the DBA/1 mouse model of sudden unexpected death in epilepsy (SUDEP), administration of a selective serotonin (5-HT) reuptake inhibitor (SSRI), fluvoxamine, completely suppressed seizure-induced respiratory arrest (S-IRA) at 30 min after administration (i.p.) in a dose-related manner without blocking audiogenic seizures (AGSz), but another SSRI, paroxetine, reduced S-IRA but with a delayed (24 h) onset and significant toxicity. A serotonin-norepinephrine reuptake inhibitor, venlafaxine, reduced S-IRA incidence, but higher doses were ineffective. A selective 5-HT7 agonist, AS-19, was totally ineffective in reducing S-IRA. In developing DBA/1 mice that had not previously experienced AGSz, administration of a nonselective 5-HT antagonist, cyproheptadine, induced a significantly greater incidence of S-IRA than that of saline. This study confirms that certain drugs that enhance the activation of 5-HT receptors are able to prevent S-IRA, but not all serotonergic drugs are equally effective, which may be relevant to the potential use of these drugs for SUDEP prevention. Serotonergic antagonists may be problematic in patients with epilepsy. PMID:25064738

  9. PLK1 blockade enhances therapeutic effects of radiation by inducing cell cycle arrest at the mitotic phase

    PubMed Central

    Inoue, Minoru; Yoshimura, Michio; Kobayashi, Minoru; Morinibu, Akiyo; Itasaka, Satoshi; Hiraoka, Masahiro; Harada, Hiroshi

    2015-01-01

    The cytotoxicity of ionizing radiation depends on the cell cycle phase; therefore, its pharmacological manipulation, especially the induction of cell cycle arrest at the radiosensitive mitotic-phase (M-phase), has been attempted for effective radiation therapy. Polo-like kinase 1 (PLK1) is a serine/threonine kinase that functions in mitotic progression, and is now recognized as a potential target for radiosensitization. We herein investigated whether PLK1 blockade enhanced the cytotoxic effects of radiation by modulating cell cycle phases of cancer cells using the novel small molecule inhibitor of PLK1, TAK-960. The TAK-960 treatment exhibited radiosensitizing effects in vitro, especially when it increased the proportion of M-phase cells. TAK-960 did not sensitize cancer cells to radiation when an insufficient amount of time was provided to induce mitotic arrest. The overexpression of a PLK1 mutant, PLK1-R136G&T210D, which was confirmed to cancel the TAK-960-mediated increase in the proportion of mitotic cells, abrogated the radiosensitizing effects of TAK-960. A tumor growth delay assay also demonstrated that the radiosensitizing effects of TAK-960 depended on an increase in the proportion of M-phase cells. These results provide a rational basis for targeting PLK1 for radiosensitization when considering the therapeutic time window for M-phase arrest as the best timing for radiation treatments. PMID:26503893

  10. Platelet-activating factor induces cell cycle arrest and disrupts the DNA damage response in mast cells

    PubMed Central

    Puebla-Osorio, N; Damiani, E; Bover, L; Ullrich, S E

    2015-01-01

    Platelet-activating factor (PAF) is a potent phospholipid modulator of inflammation that has diverse physiological and pathological functions. Previously, we demonstrated that PAF has an essential role in ultraviolet (UV)-induced immunosuppression and reduces the repair of damaged DNA, suggesting that UV-induced PAF is contributing to skin cancer initiation by inducing immune suppression and also affecting a proper DNA damage response. The exact role of PAF in modulating cell proliferation, differentiation or transformation is unclear. Here, we investigated the mechanism(s) by which PAF affects the cell cycle and impairs early DNA damage response. PAF arrests proliferation in transformed and nontransformed human mast cells by reducing the expression of cyclin-B1 and promoting the expression of p21. PAF-treated cells show a dose-dependent cell cycle arrest mainly at G2–M, and a decrease in the DNA damage response elements MCPH1/BRIT-1 and ataxia telangiectasia and rad related (ATR). In addition, PAF disrupts the localization of p-ataxia telangiectasia mutated (p-ATM), and phosphorylated-ataxia telangiectasia and rad related (p-ATR) at the site of DNA damage. Whereas the potent effect on cell cycle arrest may imply a tumor suppressor activity for PAF, the impairment of proper DNA damage response might implicate PAF as a tumor promoter. The outcome of these diverse effects may be dependent on specific cues in the microenvironment. PMID:25950475

  11. Formononetin suppresses the proliferation of human non-small cell lung cancer through induction of cell cycle arrest and apoptosis.

    PubMed

    Yang, Yi; Zhao, Yi; Ai, Xinghao; Cheng, Baijun; Lu, Shun

    2014-01-01

    Formononetin is a novel herbal isoflavonoid isolated from Astragalus membranaceus and possesses antitumorigenic properties. In the present study, we investigated the anti-proliferative effects of formononetin on human non-small cell lung cancer (NSCLC), and further elucidated the molecular mechanism underlying the anti-tumor property. MTT assay showed that formononetin treatment significantly inhibited the proliferation of two NSCLC cell lines including A549 and NCI-H23 in a time- and dose-dependent manner. Flow cytometric analysis demonstrated that formononetin induced G1-phase cell cycle arrest and promoted cell apoptosis in NSCLC cells. On the molecular level, we observed that exposure to formononetin altered the expression levels of cell cycle arrest-associated proteins p21, cyclin A and cyclin D1. Meanwhile, the apoptosis-related proteins cleaved caspase-3, bax and bcl-2 were also changed following treatment with formononetin. In addition, the expression level of p53 was dose-dependently upregulated after administration with formononetin. We also found that formononetin treatment increased the phosphorylation of p53 at Ser15 and Ser20 and enhances its transcriptional activity in a dose-dependent manner. Collectively, these results demonstrated that formononetin might be a potential chemopreventive drug for lung cancer therapy through induction of cell cycle arrest and apoptosis in NSCLC cells. PMID:25674209

  12. Cucurbitacin B Causes Increased Radiation Sensitivity of Human Breast Cancer Cells via G2/M Cell Cycle Arrest

    PubMed Central

    Duangmano, Suwit; Sae-lim, Phorntip; Suksamrarn, Apichart; Patmasiriwat, Pimpicha; Domann, Frederick E.

    2012-01-01

    Purpose. To explore the effects of cucurbitacin B on the radiation survival of human breast cancer cells and to elucidate the cellular mechanism of radiosensitization if any. Materials and Methods. Human breast carcinoma cell lines were treated with cucurbitacin B before irradiation with 0–10 Gy of 137Cs gamma rays. The effect of cucurbitacin B on cell-survival following irradiation was evaluated by colony-forming assay. Cell cycle distributions were investigated using flow cytometry. Real-time PCR and western blots were performed to investigate the expression of cell cycle checkpoints. Results. Cucurbitacin B inhibited breast cancer cell proliferation in a dose-dependent manner. Only MDA-MB-231 and MCF7:5C cells but not SKBR-3 cells were radiosensitized by cucurbitacin B. Flow cytometric analysis for DNA content indicated that cucurbitacin B resulted in G2/M arrest in MDA-MB-231 and MCF7:5C but not SKBR-3 cells. Moreover, Real-time PCR and western blot analysis demonstrated upregulated p21 expression before irradiation, a likely cause of the cell cycle arrest. Conclusion. Taken together, these findings suggest that cucurbitacin B causes radiosensitization of some breast cancer cells, and that cucurbitacin B induced G2/M arrest is an important mechanism. Therefore, combinations of cucurbitacin B with radiotherapy may be appropriate for experimental breast cancer treatment. PMID:22690217

  13. MDA-7 results in downregulation of AKT concomitant with apoptosis and cell cycle arrest in breast cancer cells

    PubMed Central

    Valero, V; Wingate, H; Chada, S; Liu, Y; Palalon, F; Mills, G; Keyomarsi, K; Hunt, KK

    2013-01-01

    The melanoma differentiation-associated gene-7 (mda-7) is a known mediator of apoptosis in cancer cells but not in normal cells. We hypothesized that MDA-7 interferes with the prosurvival signaling pathways that are commonly altered in cancer cells to induce growth arrest and apoptosis. We also identified the cell signaling pathways that are antagonized by MDA-7 leading to apoptosis. Using an adenoviral expression system, mda-7 was introduced into the breast cancer cell lines SKBr3, MCF-7 and MDA-MB-468, each with a different estrogen receptor (ER) and HER-2 receptor status. Downstream targets of MDA-7 were assessed by reverse phase protein array analysis, western blot analysis and immunofluorescence confocal microscopy. Our results show that MDA-7-induced apoptosis was mediated by caspases in all cell lines tested. However, MDA-7 modulates additional pathways in SKBr3 (HER-2 positive) and MCF-7 (ER positive) cells including downregulation of AKT-GSK3β and upregulation of cyclin-dependent kinase inhibitors in the nucleus. This leads to cell cycle arrest in addition to apoptosis. In conclusion, MDA-7 abrogates tumor-promoting pathways including the activation of caspase-dependent signaling pathways ultimately leading to apoptosis. In addition, depending on the phenotype of the breast cancer cell, MDA-7 modulates cell cycle regulating pathways to mediate cell cycle arrest. PMID:21546925

  14. Natural pesticide dihydrorotenone arrests human plasma cancer cells at the G0/G1 phase of the cell cycle.

    PubMed

    Xu, Xin; Zhang, Jieyu; Han, Kunkun; Zhang, Zubin; Chen, Guodong; Zhang, Jinping; Mao, Xinliang; Cao, Biyin

    2014-05-01

    Dihydrorotenone (DHR) is a natural pesticide used for farming including organic produces. We recently found that DHR induces human plasma cell apoptosis by provoking endoplasmic reticulum stress. In the present study, we found that DHR arrested human plasma cancer cells at the G0/G1 phase of the cell cycle. Mechanistical studies demonstrated that cell cycle arrest was associated with downregulated cell cycle promotors including cyclin D2, cyclin D3, cyclin-dependent kinases (CDK4, CKD6), and phosphorylated-Rb. DHR inhibited cyclin D2 transactivation, thus inhibiting its mRNA expression. In addition, DHR upregulated the cell cycle repressors p21 and p53. DHR also increased the phosphorylation level of p53, suggesting the upregulated transactivation function of p53, which was confirmed by the induction of p21, a substrate of activated p53. Moreover, DHR downregulated AKT and ERK phosphorylation, an incentive of cell cycle progression. Therefore, these results collectively demonstrated that DHR disrupts the cell cycle progress, which suggests that DHR is toxic to human plasma cells. Caution is thus suggested when handling with this agent. PMID:24615755

  15. Terpenoids inhibit Candida albicans growth by affecting membrane integrity and arrest of cell cycle.

    PubMed

    Zore, Gajanan B; Thakre, Archana D; Jadhav, Sitaram; Karuppayil, S Mohan

    2011-10-15

    Anti-Candida potential of six terpenoids were evaluated in this study against various isolates of Candida albicans (n=39) and non-C. albicans (n=9) that are differentially susceptible to fluconazole. All the six terpenoids tested, showed excellent activity and were equally effective against isolates of Candida sps., tested in this study. Linalool and citral were the most effective ones, inhibiting all the isolates at ≤0.064% (v/v). Five among the six terpenoids tested were fungicidal. Time dependent kill curve assay showed that MFCs of linalool and eugenol were highly toxic to C. albicans, killing 99.9% inoculum within seven min of exposure, while that of citronellal, linalyl acetate and citral required 15min, 1h and 2h, respectively. FIC index values (Linalool - 0.140, benzyl benzoate - 0.156, eugenol - 0.265, citral - 0.281 and 0.312 for linalyl acetate and citronellal) and isobologram obtained by checker board assay showed that all the six terpenoids tested exhibit excellent synergistic activity with fluconazole against a fluconazole resistant strain of C. albicans. Terpenoids tested arrested C. albicans cells at different phases of the cell cycle i.e. linalool and LA at G1, citral and citronellal at S phase and benzyl benzoate at G2-M phase and induced apoptosis. Linalool, citral, citronellal and benzyl benzoate caused more than 50% inhibition of germ tube induction at 0.008%, while eugenol and LA required 0.032 and 0.016% (v/v) concentrations, respectively. MICs of all the terpenoids for the C. albicans growth were non toxic to HeLa cells. Terpenoids tested exhibited excellent activity against C. albicans yeast and hyphal form growth at the concentrations that are non toxic to HeLa cells. Terpenoids tested in this study may find use in antifungal chemotherapy, not only as antifungal agents but also as synergistic agents along with conventional drugs like fluconazole. PMID:21596542

  16. Ethanol extract of Innotus obliquus (Chaga mushroom) induces G1 cell cycle arrest in HT-29 human colon cancer cells

    PubMed Central

    Lee, Hyun Sook; Kim, Eun Ji

    2015-01-01

    BACKGROUND/OBJECTIVES Inonotus obliquus (I. obliquus, Chaga mushroom) has long been used as a folk medicine to treat cancer. In the present study, we examined whether or not ethanol extract of I. obliquus (EEIO) inhibits cell cycle progression in HT-29 human colon cancer cells, in addition to its mechanism of action. MATERIALS/METHODS To examine the effects of Inonotus obliquus on the cell cycle progression and the molecular mechanism in colon cancer cells, HT-29 human colon cancer cells were cultured in the presence of 2.5 - 10 µg/mL of EEIO, and analyzed the cell cycle arrest by flow cytometry and the cell cycle controlling protein expression by Western blotting. RESULTS Treatment cells with 2.5 - 10 µg/mL of EEIO reduced viable HT-29 cell numbers and DNA synthesis, increased the percentage of cells in G1 phase, decreased protein expression of CDK2, CDK4, and cyclin D1, increased expression of p21, p27, and p53, and inhibited phosphorylation of Rb and E2F1 expression. Among I. obliquus fractions, fraction 2 (fractionated by dichloromethane from EEIO) showed the same effect as EEIO treatment on cell proliferation and cell cycle-related protein levels. CONCLUSIONS These results demonstrate that fraction 2 is the major fraction that induces G1 arrest and inhibits cell proliferation, suggesting I. obliquus could be used as a natural anti-cancer ingredient in the food and/or pharmaceutical industry. PMID:25861415

  17. Overexpression of GSTA2 protects against cell cycle arrest and apoptosis induced by the DNA inter-strand crosslinking nitrogen mustard, mechlorethamine.

    PubMed

    Xie, Jingping; Shults, Keith; Flye, Leanne; Jiang, Fen; Head, David R; Briggs, Robert C

    2005-05-15

    The effectiveness of bifunctional alkylating nitrogen mustard compounds in chemotherapy is related to their ability to form DNA inter-strand crosslinks. Patients exposed to DNA inter-strand crosslinking (ICL) agents subsequently experience an elevated incidence of myelodysplastic syndromes (MDS) and MDS related acute myeloid leukemia. Fanconi's anemia (FA) patients are deficient in the repair of crosslink DNA damage and they experience a high incidence of MDS. These observations indicate that hematopoietic cells are specific target for the transforming effects of DNA crosslinking damage. Changes in transcript levels were characterized in human hematopoietic cells occurring in response to the nitrogen mustard, mechlorethamine (HN2), but not in response to monofunctional analogs. Only modest changes in a few gene transcripts were detected in HL60 cells exposed to levels of HN2 tittered to maximal dose that caused growth suppression with minimal cell death and allowed eventual resumption of normal cell growth. Under conditions of transient growth suppression, a subset of glutathione-S-transferase (GST) isoenzyme genes was consistently upregulated three to fourfold by HN2, but not by monofunctional analogs. Subsequent efforts to confirm the changes detected by microarray analyses revealed an unexpected dependence on treatment conditions. The GST alpha class A2 subfamily member transcripts were upregulated 24 h after a 1 h exposure to HN2 that caused an extensive, but transient block in late S/G2 cell cycle phase, but were minimally altered with continuous exposure. The 1-h exposure to HN2 caused a transient late S/G2 cell cycle arrest in both the HL-60 cell line and the Colo 320HSR human colon cancer cell line. Overexpression of GSTA2 by transient transfection protected Colo 320HSR cells against both cycle arrest and apoptosis following exposure to HN2. Overexpression of GSTA2 in Colo 320HSR cells induced after exposure to HN2 did not alter cycle arrest or apoptosis

  18. 3,39-Diindolylmethane Ameliorates Staphylococcal Enterotoxin B–Induced Acute Lung Injury through Alterations in the Expression of MicroRNA that Target Apoptosis and Cell-Cycle Arrest in Activated T Cells.

    PubMed

    Elliott, David M; Nagarkatti, Mitzi; Nagarkatti, Prakash S

    2016-04-01

    3,39-Diindolylmethane (DIM), a natural indole found in cruciferous vegetables, has significant anti-cancer and anti-inflammatory properties. In this current study, we investigated the effects of DIM on acute lung injury (ALI) induced by exposure to staphylococcal enterotoxin B (SEB). We found that pretreatment of mice with DIM led to attenuation of SEB-induced inflammation in the lungs, vascular leak, and IFN-g secretion. Additionally, DIM could induce cell-cycle arrest and cell death in SEB-activated T cells in a concentration-dependent manner. Interestingly, microRNA (miRNA) microarray analysis uncovered an altered miRNA profile in lung-infiltrating mononuclear cells after DIM treatment of SEB-exposed mice. Moreover, computational analysis of miRNA gene targets and regulation networks indicated that DIM alters miRNA in the cell death and cell-cycle progression pathways. Specifically, DIM treatment significantly downregulated several miRNA and a correlative increase associated gene targets. Furthermore, overexpression and inhibition studies demonstrated that DIM-induced cell death, at least in part, used miR-222. Collectively, these studies demonstrate for the first time that DIM treatment attenuates SEB-induced ALI and may do so through the induction of microRNAs that promote apoptosis and cell-cycle arrest in SEB-activated T cells. PMID:26818958

  19. pRB plays an essential role in cell cycle arrest induced by DNA damage

    PubMed Central

    Harrington, Elizabeth A.; Bruce, Jacqueline L.; Harlow, Ed; Dyson, Nicholas

    1998-01-01

    To maintain genome stability, cells with damaged DNA must arrest to allow repair of mutations before replication. Although several key components required to elicit this arrest have been discovered, much of the pathway remains elusive. Here we report that pRB acts as a central mediator of the proliferative block induced by a diverse range of DNA damaging stimuli. Rb−/− mouse embryo fibroblasts are defective in arrest after γ-irradiation, UV irradiation, and treatment with a variety of chemotherapeutic drugs. In contrast, the pRB related proteins p107 and p130 do not play an essential part in the DNA damage response. pRB is required specifically for the G1/S phase checkpoint induced by γ-irradiation. Despite a defect in G1/S phase arrest, levels of p53 and p21 are increased normally in Rb−/− cells in response to γ-irradiation. These results lead us to propose a model in which pRB acts as an essential downstream target of the DNA damage-induced arrest pathway. The ability of pRB to prevent replication of damaged DNA is likely to inhibit the propagation of carcinogenic mutations and may therefore contribute to its role as a tumor suppressor. Furthermore, because many cancer therapies act by damaging DNA, these findings also have implications for the treatment of tumors in which pRB is inactivated. PMID:9751770

  20. Transcription factor-pathway co-expression analysis reveals cooperation between SP1 and ESR1 on dysregulating cell cycle arrest in non-hyperdiploid multiple myeloma

    PubMed Central

    Wang, Xujun; Yan, Zhenyu; Fulciniti, Mariateresa; Li, Yingxiang; Gkotzamanidou, Maria; Amin, Samir B; Shah, Parantu K; Zhang, Yong

    2014-01-01

    Multiple myeloma is a hematological cancer of plasma B-cells and remains incurable. Two major subtypes of myeloma, hyperdiploid (HMM) and non-hyperdiploid myeloma (NHMM), have distinct chromosomal alterations and different survival outcomes. Transcription factors (TrFs) have been implicated in myeloma oncogenesis but their dysregulation in myeloma subtypes are less studied. Here we develop a TrF-pathway co-expression analysis to identify altered co-expression between two sample types. We apply the method to the two myeloma subtypes and the cell cycle arrest pathway, which is significantly differentially expressed between the two subtypes. We find that TrFs MYC, NF-κB and HOXA9 have significantly lower co-expression with cell cycle arrest in HMM, co-occurring with their over-activation in HMM. In contrast, TrFs ESR1, SP1 and E2F1 have significantly lower co-expression with cell cycle arrest in NHMM. SP1 ChIP targets are enriched by cell cycle arrest genes. These results motivate a cooperation model of ESR1 and SP1 in regulating cell cycle arrest, and a hypothesis that their over-activation in NHMM disrupts proper regulation of cell cycle arrest. Co-targeting ESR1 and SP1 shows a synergistic effect on inhibiting myeloma proliferation in NHMM cell lines. Therefore, studying TrF-pathway co-expression dysregulation in human cancers facilitates forming novel hypotheses towards clinical utility. PMID:23925045

  1. Inhibition of mTOR signaling protects photoreceptor cells against serum deprivation by reducing oxidative stress and inducing G2/M cell cycle arrest

    PubMed Central

    FAN, BIN; LI, FU-QAING; SONG, JING-YAO; CHEN, XU; LI, GUANG-YU

    2016-01-01

    The mammalian target of rapamycin (mTOR) pathway is a crucial cellular signaling hub, which integrates internal and external cues to modulate the cell cycle, protein synthesis and metabolism. The present study hypothesized that inhibiting mTOR signaling may induce cells to enter lower and more stable bioenergetic states, in which neurons have greater resistance to various insults. Neurotrophin withdrawal from photoreceptor cells (661W cells) was mimicked using serum deprivation, and the neuroprotective mechanisms were studied following suppression of the mTOR pathway. Treatment with an mTOR specific inhibitor, rapamycin, reduced intracellular levels of reactive oxygen species, suppressed oxidative stress, and attenuated mitochondrial dysfunction. In addition, inhibiting mTOR signaling induced a G2/M cell cycle arrest, thus providing an opportunity to repair damaged DNA and block the cell death cascade. These results suggested that inhibition of mTOR had a neuroprotective effect on serum-deprived 661W cells. In conclusion, the mTOR pathway is a critical molecular signal for cell cycle regulation and energy metabolism, and inhibiting the mTOR pathway may attenuate neurotrophin withdrawal-induced damage. These observations may provide evidence for the treatment of retinal degenerative disease, since inducing neurons into a lower and more stable bioenergetic state by blocking mTOR signaling may slow the progression of neurodegenerative diseases. PMID:27035647

  2. Lycopene and beta-carotene induce cell-cycle arrest and apoptosis in human breast cancer cell lines.

    PubMed

    Gloria, Nathalie Fonseca; Soares, Nathalia; Brand, Camila; Oliveira, Felipe Leite; Borojevic, Radovan; Teodoro, Anderson Junger

    2014-03-01

    Lycopene and beta-carotene are carotenoids widely distributed in fruits and vegetables, with potential anticancer activity. Epidemiological trials rarely provide evidence for the mechanisms of action of these compounds, and their biological effects at different times of treatment are still unclear. The aim of the present study was to determine the effect of carotenoids on the cell cycle and cell viability in human breast cancer cell lines. Human breast cell lines were treated with carotenoids (0.5-10 μM) for 48 and 96 h. Cell viability was monitored using the MTT method (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide; thiazolyl blue). The cell cycle was analyzed by flow cytometry, and apoptotic cells were identified by annexin/propidium iodide (PI) biomarkers. Our data showed a significant decrease in the number of viable breast cancer cells on treatment with carotenoids. Carotenoids also promoted cell-cycle arrest followed by decreased cell viability in the majority of cell lines after 96 h, compared to controls. Furthermore, an increase in apoptosis was observed in cell lines when cells were treated with carotenoids. Our findings show the capacity of lycopene and beta-carotene to inhibit cell proliferation, arrest the cell cycle in different phases, and increase apoptosis. These findings indicate that the effect was cell type-dependent and that carotenoids are potential agents for biological interference with cancer. PMID:24596385

  3. Rhizoma Paridis Saponins Induces Cell Cycle Arrest and Apoptosis in Non-Small Cell Lung Carcinoma A549 Cells

    PubMed Central

    Zhang, Jue; Yang, Yixi; Lei, Lei; Tian, Mengliang

    2015-01-01

    Background As a traditional Chinese medicine herb, Chonglou (Paris polyphylla var. chinensis) has been used as anticancer medicine in China in recent decades, as it can induce cell cycle arrest and apoptosis in numerous cancer cells. The saponins extract from the rhizoma of Chonglou [Rhizoma Paridis saponins (RPS)] is known as the main active component for anticancer treatment. However, the molecular mechanism of the anticancer effect of RPS is unknown. Material/Methods The present study evaluated the effect of RPS in non-small-cell lung cancer (NSCLC) A549 cells using the 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyl tetrazolium bromide (MTT) assay and flow cytometry. Subsequently, the expression of several genes associated with cell cycle and apoptosis were detected by reverse transcription-quantitative polymerase chain reaction (qRT-PCR) and Western blotting. Results RPS was revealed to inhibit cell growth, causing a number of cells to accumulate in the G 1 phase of the cell cycle, leading to apoptosis. In addition, the effect was dose-dependent. Moreover, the results of qRT-PCR and Western blotting showed that p53 and cyclin-dependent kinase 2 (CDK2) were significantly downregulated, and that BCL2, BAX, and p21 were upregulated, by RPS treatment. Conclusions We speculated that the RPS could act on a pathway, including p53, p21, BCL2, BAX, and CDK2, and results in G1 cell cycle arrest and apoptosis in NSCLC cells. PMID:26311066

  4. Suppression of urinary bladder urothelial carcinoma cell by the ethanol extract of pomegranate fruit through cell cycle arrest and apoptosis

    PubMed Central

    2013-01-01

    Background Pomegranate possesses many medicinal properties such as antioxidant, anti-inflammation and antitumor. It has been extensively used as a folk medicine by many cultures. Pomegranate fruit has been shown to have the inhibitory efficacy against prostate cancer and lung cancer in vitro and in vivo. It can be exploited in chemoprevention and chemotherapy of prostate cancer. In this study we examined the anti-cancer efficacy of pomegranate fruit grown in Taiwan against urinary bladder urothelial carcinoma (UBUC) and its mechanism of action. Methods Edible portion of Taiwanese pomegranate was extracted using ethanol and the anti-cancer effectiveness of ethanol extract was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Flow cytometry and western immunoblotting were exploited to uncover the molecular pathways underlying anti-UBUC activity of Taiwanese pomegranate ethanol extract. Results This study demonstrated that Taiwanese pomegranate fruit ethanol extract (PEE) could effectively restrict the proliferation of UBUC T24 and J82 cells. Cell cycle analyses indicated that the S phase arrest induced by PEE treatment might be caused by an increase in cyclin A protein level and a decrease in the expression of cyclin-dependent kinase 1. The results of western immunoblotting demonstrated that PEE treatment could not only evoke the activation of pro-caspase-3, -8,-9 but also increase Bax/Bcl-2 ratio in T24 cells. The above observations implicated that PEE administration might trigger the apoptosis in T24 cells through death receptor signaling and mitochondrial damage pathway. Besides we found that PEE exposure to T24 cells could provoke intensive activation of procaspase-12 and enhance the expressions of CHOP and Bip, endoplasmic reticulum (ER) stress marker, suggesting that ER stress might be the cardinal apoptotic mechanism of PEE-induced inhibition of bladder cancer cell. Conclusions The analytical results of this study help to provide

  5. Early Activation of the Kynurenine Pathway Predicts Early Death and Long‐term Outcome in Patients Resuscitated From Out‐of‐Hospital Cardiac Arrest

    PubMed Central

    Ristagno, Giuseppe; Latini, Roberto; Vaahersalo, Jukka; Masson, Serge; Kurola, Jouni; Varpula, Tero; Lucchetti, Jacopo; Fracasso, Claudia; Guiso, Giovanna; Montanelli, Alessandro; Barlera, Simona; Gobbi, Marco; Tiainen, Marjaana; Pettilä, Ville; Skrifvars, Markus B.

    2014-01-01

    Background The kynurenine pathway (KP) is the major route of tryptophan (TRP) catabolism and is activated by inflammation and after cardiac arrest in animals. We hypothesized that the KP activation level correlates with severity of post–cardiac arrest shock, early death, and long‐term outcome. Methods and Results Plasma was obtained from 245 patients enrolled in a prospective multicenter observational study in 21 intensive care units in Finland. Time to return of spontaneous circulation, lowest systolic arterial pressure, and bicarbonate during the first 24 hours were collected. A cerebral performance category of 3 to 5 defined 12‐month poor outcome. Plasma TRP and KP metabolites, kynurenine (KYN), kynurenic acid, 3‐hydroxyanthranilic acid, and the ratio of KYN to TRP were measured by liquid chromatography and mass spectrometry. All KP metabolites at intensive care unit admission were significantly higher in cardiac arrest patients with a nonshockable rhythm compared to those with a shockable rhythm, and kynurenic acid and 3‐hydroxyanthranilic acid correlated with time to return of spontaneous circulation. Patients with higher levels of KYN, KYN to TRP, kynurenic acid, and 3‐hydroxyanthranilic acid had lower 24‐hour systolic arterial pressure and bicarbonate. All KP metabolites and the ratio of KYN to TRP, but not TRP, were significantly higher in patients who died in the intensive care unit in comparison to those who survived. Multivariable logistic regression showed that high kynurenic acid (odds ratio: 1.004; 95% confidence interval: 1.001 to 1.008; P=0.014), and 3‐hydroxyanthranilic acid (odds ratio: 1.011; 95% confidence interval: 1.001 to 1.022; P=0.03) were independently associated with 12‐month poor outcome and significantly improved risk reclassification. Conclusions KP is activated early after cardiac arrest and is associated with severity of post–cardiac arrest shock, early death, and poor long‐term outcome. PMID:25092787

  6. The Inhibition of Polo Kinase by Matrimony Maintains G2 Arrest in the Meiotic Cell Cycle

    PubMed Central

    Xiang, Youbin; Takeo, Satomi; Florens, Laurence; Hughes, Stacie E; Huo, Li-Jun; Gilliland, William D; Swanson, Selene K; Teeter, Kathy; Schwartz, Joel W; Washburn, Michael P; Jaspersen, Sue L; Hawley, R. Scott

    2007-01-01

    Many meiotic systems in female animals include a lengthy arrest in G2 that separates the end of pachytene from nuclear envelope breakdown (NEB). However, the mechanisms by which a meiotic cell can arrest for long periods of time (decades in human females) have remained a mystery. The Drosophila Matrimony (Mtrm) protein is expressed from the end of pachytene until the completion of meiosis I. Loss-of-function mtrm mutants result in precocious NEB. Coimmunoprecipitation experiments reveal that Mtrm physically interacts with Polo kinase (Polo) in vivo, and multidimensional protein identification technology mass spectrometry analysis reveals that Mtrm binds to Polo with an approximate stoichiometry of 1:1. Mutation of a Polo-Box Domain (PBD) binding site in Mtrm ablates the function of Mtrm and the physical interaction of Mtrm with Polo. The meiotic defects observed in mtrm/+ heterozygotes are fully suppressed by reducing the dose of polo+, demonstrating that Mtrm acts as an inhibitor of Polo. Mtrm acts as a negative regulator of Polo during the later stages of G2 arrest. Indeed, both the repression of Polo expression until stage 11 and the inactivation of newly synthesized Polo by Mtrm until stage 13 play critical roles in maintaining and properly terminating G2 arrest. Our data suggest a model in which the eventual activation of Cdc25 by an excess of Polo at stage 13 triggers NEB and entry into prometaphase. PMID:18052611

  7. Anticancer Activity of Novel Daphnane Diterpenoids from Daphne genkwa through Cell-Cycle Arrest and Suppression of Akt/STAT/Src Signalings in Human Lung Cancer Cells.

    PubMed

    Jo, Si-Kyoung; Hong, Ji-Young; Park, Hyen Joo; Lee, Sang Kook

    2012-11-01

    Although the immense efforts have been made for cancer prevention, early diagnosis, and treatment, cancer morbidity and mortality has not been decreased during last forty years. Especially, lung cancer is top-ranked in cancer-associated human death. Therefore, effective strategy is strongly required for the management of lung cancer. In the present study, we found that novel daphnane diterpenoids, yuanhualine (YL), yuanhuahine (YH) and yuanhuagine (YG) isolated from the flower of Daphne genkwa (Thymelaeaceae), exhibited potent anti-proliferative activities against human lung A549 cells with the IC50 values of 7.0, 15.2 and 24.7 nM, respectively. Flow cytometric analysis revealed that the daphnane diterpenoids induced cell-cycle arrest in the G0/G1 as well as G2/M phase in A549 cells. The cell-cycle arrests were well correlated with the expression of checkpoint proteins including the up-regulation of cyclin-dependent kinase inhibitor p21 and p53 and down-regulation of cyclin A, cyclin B1, cyclin E, cyclin dependent kinase 4, cdc2, phosphorylation of Rb and cMyc expression. In the analysis of signal transduction molecules, the daphnane diterpenoids suppressed the activation of Akt, STAT3 and Src in human lung cancer cells. The daphnane diterpenoids also exerted the potent anti-proliferative activity against anticancer-drug resistant cancer cells including gemcitabine-resistant A549, gefitinib-, erlotinib-resistant H292 cells. Synergistic effects in the growth inhibition were also observed when yuanhualine was combined with gemcitabine, gefitinib or erlotinib in A549 cells. Taken together, these findings suggest that the novel daphnane diterpenoids might provide lead candidates for the development of therapeutic agents for human lung cancers. PMID:24009843

  8. Prognostic factors for death and survival with or without complications in cardiac arrest patients receiving CPR within 24 hours of anesthesia for emergency surgery

    PubMed Central

    Siriphuwanun, Visith; Punjasawadwong, Yodying; Lapisatepun, Worawut; Charuluxananan, Somrat; Uerpairojkit, Ketchada

    2014-01-01

    Purpose To determine prognostic factors for death and survival with or without complications in cardiac arrest patients who received cardiopulmonary resuscitation (CPR) within 24 hours of receiving anesthesia for emergency surgery. Patients and methods A retrospective cohort study approved by the Maharaj Nakorn Chiang Mai University Hospital Ethical Committee. Data used were taken from records of 751 cardiac arrest patients who received their first CPR within 24 hours of anesthesia for emergency surgery between January 1, 2003 and October 31, 2011. The reviewed data included patient characteristics, surgical procedures, American Society of Anesthesiologist (ASA) physical status classification, anesthesia information, the timing of cardiac arrest, CPR details, and outcomes at 24 hours after CPR. Univariate and polytomous logistic regression analyses were used to determine prognostic factors associated with the outcome variable. P-values of less than 0.05 were considered statistically significant. Results The outcomes at 24 hours were death (638/751, 85.0%), survival with complications (73/751, 9.7%), and survival without complications (40/751, 5.3%). The prognostic factors associated with death were: age between 13–34 years (OR =3.08, 95% CI =1.03–9.19); ASA physical status three and higher (OR =6.60, 95% CI =2.17–20.13); precardiopulmonary comorbidity (OR =3.28, 95% CI =1.09–9.90); the condition of patients who were on mechanical ventilation prior to receiving anesthesia (OR =4.11, 95% CI =1.17–14.38); surgery in the upper abdominal site (OR =14.64, 95% CI =2.83–75.82); shock prior to cardiac arrest (OR =6.24, 95% CI =2.53–15.36); nonshockable electrocardiography (EKG) rhythm (OR =5.67, 95% CI =1.93–16.62); cardiac arrest occurring in postoperative period (OR =7.35, 95% CI =2.89–18.74); and duration of CPR more than 30 minutes (OR =4.32, 95% CI =1.39–13.45). The prognostic factors associated with survival with complications were being greater

  9. Studies with GFP-Vpr fusion proteins: induction of apoptosis but ablation of cell-cycle arrest despite nuclear membrane or nuclear localization.

    PubMed

    Waldhuber, Megan G; Bateson, Michael; Tan, Judith; Greenway, Alison L; McPhee, Dale A

    2003-08-15

    The human immunodeficiency virus type 1 (HIV-1) Vpr protein is known to arrest the cell cycle in G(2)/M and induce apoptosis following arrest. The functions of Vpr relative to its location in the cell remain unresolved. We now demonstrate that the location and function of Vpr are dependent on the makeup of fusion proteins and that the functions of G(2)/M arrest and apoptosis are separable. Using green fluorescence protein mutants (EGFP or EYFP), we found that fusion at either the N- or C-terminus compromised the ability of Vpr to arrest cell cycling, relative to that of His-Vpr or wild-type protein. Additionally, utilizing the ability to specifically identify cells expressing the fusion proteins, we confirm that Vpr can induce apoptosis, but appears to be independent of cell-cycle arrest in G(2)/M. Both N- and C-terminal Vpr/EYFP fusion proteins induced apoptosis but caused minimal G(2)/M arrest. These studies with Vpr fusion proteins indicate that the functions of Vpr leading to G(2)/M arrest and apoptosis are separable and that fusion of Vpr to EGFP or EYFP affected the localization of the protein. Our findings suggest that nuclear membrane localization and nuclear import and export are strongly governed by modification of the N-terminus of Vpr. PMID:12951024

  10. Xanthones from the Leaves of Garcinia cowa Induce Cell Cycle Arrest, Apoptosis, and Autophagy in Cancer Cells.

    PubMed

    Xia, Zhengxiang; Zhang, Hong; Xu, Danqing; Lao, Yuanzhi; Fu, Wenwei; Tan, Hongsheng; Cao, Peng; Yang, Ling; Xu, Hongxi

    2015-01-01

    Two new xanthones, cowaxanthones G (1) and H (2), and 23 known analogues were isolated from an acetone extract of the leaves of Garcinia cowa. The isolated compounds were evaluated for cytotoxicity against three cancer cell lines and immortalized HL7702 normal liver cells, whereby compounds 1, 5, 8, and 15-17 exhibited significant cytotoxicity. Cell cycle analysis using flow cytometry showed that 5 induced cell cycle arrest at the S phase in a dose-dependent manner, 1 and 16 at the G2/M phase, and 17 at the G1 phase, while 16 and 17 induced apoptosis. Moreover, autophagy analysis by GFP-LC3 puncta formation and western blotting suggested that 17 induced autophagy. Taken together, our results suggest that these xanthones possess anticancer activities targeting cell cycle, apoptosis, and autophagy signaling pathways. PMID:26102071

  11. Crude extract of Rheum palmatum L. Induces cell cycle arrest S phase and apoptosis through mitochondrial-dependent pathways in U-2 OS human osteosarcoma cells.

    PubMed

    Lin, Chin-Chung; Lee, Ming-Huei; Lin, Ju-Hwa; Lin, Meng-Liang; Chueh, Fu-Shin; Yu, Chien-Chih; Lin, Jing-Pin; Chou, Yu-Cheng; Hsu, Shu-Chun; Chung, Jing-Gung

    2016-08-01

    Cancer is the second cause of death in children. Osteosarcoma is the most common primary malignancy of solid bone cancer primarily affecting adolescents and young adults. In the Chinese population, the crude extract of Rheum palmatum L. (CERP) has been used for treating different diseases, including SARS, rheumatoid arthritis, coxsackievirus B3, and human colon cancer cell, pancreatic cancer. There are no reports on CERP and human osteosarcoma cells. The present study examined effects of CERP on cytotoxicity including cell cycle distribution and cell death (apoptosis) in U-2 OS human osteosarcoma cells. CERP significantly induced S phase arrest in U-2 OS cells in a dose-dependent. CERP produced DNA damage and DNA condensation. Other effects of CERP were stimulation of ROS and Ca(2+) , mitochondria impairment, and activation of caspase-3, -8, and -9. CERP increased the levels of Bax, Bak, Bad, cyclin B, Fas, PARP, GRP78, GADD153, AIF, Endo G, Calpain-2, p21, and p27, but decreased the levels of Bcl-2, BCL-X, XIAP, Akt, CDC25A, CDK2, Cyclin A, and Cyclin E of U-2 OS cells. It was also observed that CERP promoted the expression of AIF, Endo G, GADD153, and cytochrome c. These results indicate that CERP has anticancer effects in vitro and provide the foundation for in vivo studies of animal models of osteosarcoma. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 957-969, 2016. PMID:25689151

  12. Ligand modulation of a dinuclear platinum compound leads to mechanistic differences in cell cycle progression and arrest

    PubMed Central

    Menon, Vijay R.; Peterson, Erica J.; Valerie, Kristoffer; Farrell, Nicholas P.; Povirk, Lawrence F.

    2013-01-01

    Despite similar structures and DNA binding profiles, two recently synthesized dinuclear platinum compounds are shown to elicit highly divergent effects on cell cycle progression. In colorectal HCT116 cells, BBR3610 shows a classical G2/M arrest with initial accumulation in S phase, but the derivative compound BBR3610-DACH, formed by introduction of the 1,2-diaminocyclohexane (DACH) as carrier ligand, results in severe G1/S as well as G2/M phase arrest, with nearly complete S phase depletion. The origin of this unique effect was studied. Cellular interstrand crosslinking as assayed by comet analysis was similar for both compounds, confirming previous in vitro results obtained on plasmid DNA. Immunoblotting revealed a stabilization of p53 and concomitant transient increases in p21 and p27 proteins after treatment with BBR3610-DACH. Cell viability assays and cytometric analysis of p53 and p21 null cells indicated that BBR3610-DACH-induced cell cycle arrest was p21-dependent and partially p53-dependent. However, an increase in the levels of cyclin E was observed with steady state levels of CDK2 and Cdc25A, suggesting that the G1 block occurs downstream of CDK/cyclin complex formation. The G2/M block was corroborated with decreased levels of cyclin A and cyclin B1. Surprisingly, BBR3610-DACH-induced G1 block was independent of ATM and ATR. Finally, both compounds induced apoptosis, with BBR3610-DACH showing a robust PARP-1 cleavage that was not associated with caspase-3/7 cleavage. In summary, BBR3610-DACH is a DNA binding platinum agent with unique inhibitory effects on cell cycle progression that could be further developed as a chemotherapeutic agent complementary to cisplatin and oxaliplatin. PMID:24161784

  13. Downregulation of FOXP1 Inhibits Cell Proliferation in Hepatocellular Carcinoma by Inducing G1/S Phase Cell Cycle Arrest.

    PubMed

    Wang, Xin; Sun, Ji; Cui, Meiling; Zhao, Fangyu; Ge, Chao; Chen, Taoyang; Yao, Ming; Li, Jinjun

    2016-01-01

    Forkhead box P1 (FOXP1) belongs to a family of winged-helix transcription factors that are involved in the processes of cellular proliferation, differentiation, metabolism, and longevity. FOXP1 can affect cell proliferation and migratory ability in hepatocellular carcinoma (HCC) in vitro. However, little is known about the mechanism of FOXP1 in the proliferation of HCC cells. This study aimed to further explore the function of FOXP1 on the proliferation of HCC cells as well as the relevant mechanism involved. Western blot analysis, tumor xenograft models, and flow cytometry analysis were performed to elucidate the function of FOXP1 in the regulation of cell proliferation in human HCC. We observed that silencing FOXP1 significantly suppressed the growth ability of HCC cells both in vitro and in vivo. In addition, knockdown of FOXP1 induced G1/S phase arrest, and the expression of total and phosphorylated Rb (active type) as well as the levels of E2F1 were markedly decreased at 24 h; however, other proteins, including cyclin-dependent kinase (CDK) 4 and 6 and cyclin D1 did not show noticeable changes. In conclusion, downregulation of FOXP1 inhibits cell proliferation in hepatocellular carcinoma by inducing G1/S phase cell cycle arrest, and the decrease in phosphorylated Rb is the main contributor to this G1/S phase arrest. PMID:27618020

  14. Involvement of miR-15a in G0/G1 Phase Cell Cycle Arrest Induced by Porcine Circovirus Type 2 Replication

    PubMed Central

    Quan, Rong; Wei, Li; Zhu, Shanshan; Wang, Jing; Cao, Yongchang; Xue, Chunyi; Yan, Xu; Liu, Jue

    2016-01-01

    Many viruses exploit the host cell division cycle to favour their own growth. Here we demonstrated that porcine circovirus type 2 (PCV2), which is a major causative agent of an emerging and important swine disease complex, PCV2-associated diseases, caused G0/G1 cell cycle arrest through degradation of cyclin D1 and E followed by reduction of retinoblastoma phosphorylation in synchronized PCV2-infected cells dependent upon virus replication. This induction of G0/G1 cell cycle arrest promoted PCV2 replication as evidenced by increased viral protein expression and progeny virus production in the synchronized PCV2-infected cells. To delineate a mechanism of miRNAs in regulating PCV2-induced G0/G1 cell cycle arrest, we determined expression levels of some relevant miRNAs and found that only miR-15a but not miR-16, miR-21, and miR-34a was significantly changed in the PCV2-infected cells. We further demonstrated that upregulation of miR-15a promoted PCV2-induced G0/G1 cell cycle arrest via mediating cyclins D1 and E degradation, in which involves PCV2 growth. These results reveal that G0/G1 cell cycle arrest induced by PCV2 may provide favourable conditions for viral protein expression and progeny production and that miR-15a is implicated in PCV2-induced cell cycle control, thereby contributing to efficient viral replication. PMID:27302568

  15. Involvement of miR-15a in G0/G1 Phase Cell Cycle Arrest Induced by Porcine Circovirus Type 2 Replication.

    PubMed

    Quan, Rong; Wei, Li; Zhu, Shanshan; Wang, Jing; Cao, Yongchang; Xue, Chunyi; Yan, Xu; Liu, Jue

    2016-01-01

    Many viruses exploit the host cell division cycle to favour their own growth. Here we demonstrated that porcine circovirus type 2 (PCV2), which is a major causative agent of an emerging and important swine disease complex, PCV2-associated diseases, caused G0/G1 cell cycle arrest through degradation of cyclin D1 and E followed by reduction of retinoblastoma phosphorylation in synchronized PCV2-infected cells dependent upon virus replication. This induction of G0/G1 cell cycle arrest promoted PCV2 replication as evidenced by increased viral protein expression and progeny virus production in the synchronized PCV2-infected cells. To delineate a mechanism of miRNAs in regulating PCV2-induced G0/G1 cell cycle arrest, we determined expression levels of some relevant miRNAs and found that only miR-15a but not miR-16, miR-21, and miR-34a was significantly changed in the PCV2-infected cells. We further demonstrated that upregulation of miR-15a promoted PCV2-induced G0/G1 cell cycle arrest via mediating cyclins D1 and E degradation, in which involves PCV2 growth. These results reveal that G0/G1 cell cycle arrest induced by PCV2 may provide favourable conditions for viral protein expression and progeny production and that miR-15a is implicated in PCV2-induced cell cycle control, thereby contributing to efficient viral replication. PMID:27302568

  16. Extracts of centipede Scolopendra subspinipes mutilans induce cell cycle arrest and apoptosis in A375 human melanoma cells.

    PubMed

    Ma, Weina; Liu, Rui; Qi, Junpeng; Zhang, Yanmin

    2014-07-01

    Extracts from the centipede Scolopendra genus, have been used in traditional medicine for the treatment of various diseases and have been found to exhibit anticancer activity in tumor cells. To investigate the potential and associated antitumor mechanism of alcohol extracts of the centipede Scolopendra subspinipes mutilans (AECS), cell viability, cell cycle and cell apoptosis were studied and the results revealed that AECS inhibits A375 cell proliferation in a dose- and time-dependent manner. In addition, AECS was found to arrest the cell cycle of A375 cells at the S phase, which was accompanied by a marked increase in the protein levels of cyclin E and a decrease in the protein levels of cyclin D1. In a cell culture system, AECS markedly induced the apoptosis of A375 cells, which was closely associated with the effects on the Bcl-2 family, whereby decreased Bcl-2 and increased Bak, Bax and Bad expression levels were observed. The underlying mechanism of AECS inhibiting A375 cell proliferation was associated with the induction of cell cycle arrest and apoptosis, indicating that AECS may present as a potential therapeutic agent for administration in human melanoma cancer intervention. PMID:24959287

  17. Honokiol, a chemopreventive agent against skin cancer, induces cell cycle arrest and apoptosis in human epidermoid A431 cells.

    PubMed

    Chilampalli, Chandeshwari; Guillermo, Ruth; Kaushik, Radhey S; Young, Alan; Chandrasekher, Gudiseva; Fahmy, Hesham; Dwivedi, Chandradhar

    2011-11-01

    Honokiol is a plant lignan isolated from bark and seed cones of Magnolia officinalis. Recent studies from our laboratory indicated that honokiol pretreatment decreased ultraviolet B-induced skin cancer development in SKH-1 mice. The aim of the present investigation was to study the effects of honokiol on human epidermoid squamous carcinoma A431 cells and to elucidate possible mechanisms involved in preventing skin cancer. A431 cells were pretreated with different concentrations of honokiol for a specific time period and investigated for effects on apoptosis and cell cycle analysis. Treatment with honokiol significantly decreased cell viability and cell proliferation in a concentration- and time-dependent manner. Honokiol pretreatment at 50 μmol/L concentration induced G0/G1 cell cycle arrest significantly (P < 0.05) and decreased the percentage of cells in the S and G2/M phase. Honokiol down-regulated the expression of cyclin D1, cyclin D2, Cdk2, Cdk4 and Cdk6 proteins and up-regulated the expression of Cdk's inhibitor proteins p21 and p27. Pretreatment of A431 cells with honokiol leads to induction of apoptosis and DNA fragmentation. These findings indicate that honokiol provides its effects in squamous carcinoma cells by inducing cell cycle arrest at G0/G1 phase and apoptosis. PMID:21908486

  18. Pfaffosidic Fraction from Hebanthe paniculata Induces Cell Cycle Arrest and Caspase-3-Induced Apoptosis in HepG2 Cells

    PubMed Central

    da Silva, Tereza Cristina; Cogliati, Bruno; Latorre, Andréia Oliveira; Akisue, Gokithi; Nagamine, Márcia Kazumi; Haraguchi, Mitsue; Hansen, Daiane; Sanches, Daniel Soares; Dagli, Maria Lúcia Zaidan

    2015-01-01

    Hebanthe paniculata roots (formerly Pfaffia paniculata and popularly known as Brazilian ginseng) show antineoplastic, chemopreventive, and antiproliferative properties. Functional properties of these roots and their extracts are usually attributed to the pfaffosidic fraction, which is composed mainly by pfaffosides A–F. However, the therapeutic potential of this fraction in cancer cells is not yet entirely understood. This study aimed to analyze the antitumoral effects of the purified pfaffosidic fraction or saponinic fraction on the human hepatocellular carcinoma HepG2 cell line. Cellular viability, proliferation, and apoptosis were evaluated, respectively, by MTT assay, BrdU incorporation, activated caspase-3 immunocytochemistry, and DNA fragmentation assay. Cell cycle was analyzed by flow cytometry and the cell cycle-related proteins were analyzed by quantitative PCR and Western blot. The cells exposed to pfaffosidic fraction had reduced viability and cellular growth, induced G2/M at 48 h or S at 72 h arrest, and increased sub-G1 cell population via cyclin E downregulation, p27KIP1 overexpression, and caspase-3-induced apoptosis, without affecting the DNA integrity. Antitumoral effects of pfaffosidic fraction from H. paniculata in HepG2 cells originated by multimechanisms of action might be associated with cell cycle arrest in the S phase, by CDK2 and cyclin E downregulation and p27KIP1 overexpression, besides induction of apoptosis through caspase-3 activation. PMID:26075002

  19. Toona Sinensis and Moschus Decoction Induced Cell Cycle Arrest in Human Cervical Carcinoma HeLa Cells

    PubMed Central

    Zhen, Hong; Zhang, Yifei; Fang, Zhijia; Huang, Zhiwei; Shi, Ping

    2014-01-01

    Toona sinensis and Moschus are two herb materials used in traditional Chinese medicine, most commonly for their various biological activities. In this study, we investigated the inhibitory effect of three decoctions from Toona sinensis, Moschus, and Toona sinensis and Moschus in combination on cell growth in several normal and cancer cell lines by cell viability assay. The results showed that the combined decoction exhibited the strongest anticancer effects, compared to two single decoctions. The observations indicated that the combined decoction did not induce cell apoptosis and autophagy in HeLa cells by fluorescence microscopy. Flow cytometry analysis revealed that the combined decoction arrested HeLa cell cycle progression in S-phase. After the decoction incubation, among 41 cell cycle related genes, eight were reduced, while five were increased in mRNA levels by real-time PCR assay. Western blotting showed that there were no apparent changes of protein levels of Cyclin E1, while P27 expression significantly declined and the levels of CDC7 and CDK7 obviously increased. The data suggest that the RB pathway is partially responsible for the decoction-induced S-phase cell cycle arrest in HeLa cells. Therefore, the combined decoction may have therapeutic potential as an anticancer formula for certain cancers. PMID:24511319

  20. Gracillin induces apoptosis in HL60 human leukemic cell line via oxidative stress and cell cycle arrest of G1.

    PubMed

    Chen, Chuan-Rong; Zhang, Jun; Wu, Ke-Wei; Liu, Peng-Ying; Wang, Shang-Jun; Chen, Dong-Yun; Ji, Zhao-Ning

    2015-03-01

    Gracillin, a kind of steroidal saponin isolated from the root bark of wild yam Dioscorea nipponica has been reported to exert antitumor activity. In the present study, we investigated the anticancer activity of gracillin against HL60 cells, and evaluated the possible mechanism involved in its antineoplastic action. The cell proliferation was evaluated by cell counting Kit-8 (CCK-8) assay, gracillin inhibited the growth of HL60 cells in a time- and concentration-dependent manner. Flow cytometry was used to analyze the cell cycle distribution whereas Annexin V-FITC/PI flow cytometry analysis was carried out to confirm apoptosis induced by gracillin, Our results demonstrated that gracillin could induce cell cycle arrest of G1 and apoptosis in HL60 cells. Furthermore, based on the biochemical methods, induction of oxidative stress by gracillin was indicated by increased the content of malondialdehyde (MDA), and decreased superoxide dismutase (SOD) activity. In addition, real time-PCR verified the expression of apoptosis-related genes, the mRNA level of Bcl-2 was decreased dramatically, while Bax was remarkably increased by gracillin. Taken together, gracillin could induce cell cycle arrest, oxidative stress, and apoptosis in HL60 cells, and has the potential to be developed as an antitumor agent. PMID:25980181

  1. Boron neutron capture therapy induces cell cycle arrest and cell apoptosis of glioma stem/progenitor cells in vitro

    PubMed Central

    2013-01-01

    Background Glioma stem cells in the quiescent state are resistant to clinical radiation therapy. An almost inevitable glioma recurrence is due to the persistence of these cells. The high linear energy transfer associated with boron neutron capture therapy (BNCT) could kill quiescent and proliferative cells. Methods The present study aimed to evaluate the effects of BNCT on glioma stem/progenitor cells in vitro. The damage induced by BNCT was assessed using cell cycle progression, apoptotic cell ratio and apoptosis-associated proteins expression. Results The surviving fraction and cell viability of glioma stem/progenitor cells were decreased compared with differentiated glioma cells using the same boronophenylalanine pretreatment and the same dose of neutron flux. BNCT induced cell cycle arrest in the G2/M phase and cell apoptosis via the mitochondrial pathway, with changes in the expression of associated proteins. Conclusions Glioma stem/progenitor cells, which are resistant to current clinical radiotherapy, could be effectively killed by BNCT in vitro via cell cycle arrest and apoptosis using a prolonged neutron irradiation, although radiosensitivity of glioma stem/progenitor cells was decreased compared with differentiated glioma cells when using the same dose of thermal neutron exposure and boronophenylalanine pretreatment. Thus, BNCT could offer an appreciable therapeutic advantage to prevent tumor recurrence, and may become a promising treatment in recurrent glioma. PMID:23915425

  2. Ponicidin suppresses HT29 cell growth via the induction of G1 cell cycle arrest and apoptosis.

    PubMed

    Du, Jie; Chen, Chunyou; Sun, Yiqun; Zheng, Lin; Wang, Wanchen

    2015-10-01

    Ponicidin is a diterpenoid extracted from the Chinese herb Isodon adenolomus, which has been reported as a therapeutic cytotoxic drug that may be used to treat various types of human cancer. The present study aimed to determine the antitumor effects of ponicidin, and to investigate its underlying mechanisms in colorectal cancer. The HT29 colorectal cancer cell line was used to detect the cytotoxicity of various doses of ponicidin. Cell proliferation was measured using a Cell Counting kit‑8 assay. Cell cycle and apoptosis analyses were performed using flow cytometry and fluorescent microscopy. Western blot analysis was used to measure the expression levels of apoptosis‑associated proteins following treatment with ponicidin. Treatment with ponicidin significantly suppressed HT29 cell growth by inducing G1 cell cycle arrest and apoptosis. The AKT and MEK signaling pathways were also suppressed by ponicidin; however, the p38 signaling pathway was significantly activated. The expression levels of caspase 3 and Bax protein were markedly upregulated following treatment with ponicidin. These results suggest that ponicidin exerts significant antitumor effects via the induction of cell cycle arrest and apoptosis in colorectal cells. In conclusion, ponicidin acted as an inducer of apoptosis, and may be used as a therapeutic cytotoxic drug to treat human cancer, including colorectal cancer. PMID:26239027

  3. Ponicidin suppresses HT29 cell growth via the induction of G1 cell cycle arrest and apoptosis

    PubMed Central

    DU, JIE; CHEN, CHUNYOU; SUN, YIQUN; ZHENG, LIN; WANG, WANCHEN

    2015-01-01

    Ponicidin is a diterpenoid extracted from the Chinese herb Isodon adenolomus, which has been reported as a therapeutic cytotoxic drug that may be used to treat various types of human cancer. The present study aimed to determine the antitumor effects of ponicidin, and to investigate its underlying mechanisms in colorectal cancer. The HT29 colorectal cancer cell line was used to detect the cytotoxicity of various doses of ponicidin. Cell proliferation was measured using a Cell Counting kit-8 assay. Cell cycle and apoptosis analyses were performed using flow cytometry and fluorescent microscopy. Western blot analysis was used to measure the expression levels of apoptosis-associated proteins following treatment with ponicidin. Treatment with ponicidin significantly suppressed HT29 cell growth by inducing G1 cell cycle arrest and apoptosis. The AKT and MEK signaling pathways were also suppressed by ponicidin; however, the p38 signaling pathway was significantly activated. The expression levels of caspase 3 and Bax protein were markedly upregulated following treatment with ponicidin. These results suggest that ponicidin exerts significant antitumor effects via the induction of cell cycle arrest and apoptosis in colorectal cells. In conclusion, ponicidin acted as an inducer of apoptosis, and may be used as a therapeutic cytotoxic drug to treat human cancer, including colorectal cancer. PMID:26239027

  4. Hericium erinaceus polysaccharide-protein HEG-5 inhibits SGC-7901 cell growth via cell cycle arrest and apoptosis.

    PubMed

    Zan, Xinyi; Cui, Fengjie; Li, Yunhong; Yang, Yan; Wu, Di; Sun, Wenjing; Ping, Lifeng

    2015-05-01

    HEG-5 is a novel polysaccharide-protein purified from the fermented mycelia of Hericium erinaceus CZ-2. The present study aims to investigate the effects of HEG-5 on proliferation, cell cycle and apoptosis of human gastric cancer cells SGC-7901. Here, we first uncover that HEG-5 significantly inhibited the proliferation and colony formation of SGC-7901 cells by promoting apoptosis and cell cycle arrest at S phase. RT-PCR and Western blot analysis suggested that HEG-5 could decrease the expressions of Bcl2, PI3K and AKT1, while increase the expressions of Caspase-8, Caspase-3, p53, CDK4, Bax and Bad. These findings indicated that the Caspase-8/-3-dependent, p53-dependent mitochondrial-mediated and PI3k/Akt signaling pathways involved in the molecular events of HEG-5 induced apoptosis and cell cycle arrest. Thus, our study provides in vitro evidence that HEG-5 may be taken as a potential candidate for treating gastric cancer. PMID:25703932

  5. IARS2 silencing induces non-small cell lung cancer cells proliferation inhibition, cell cycle arrest and promotes cell apoptosis.

    PubMed

    Yin, J; Liu, W; Li, R; Liu, J; Zhang, Y; Tang, W; Wang, K

    2016-01-01

    The purpose of this study was to investigate the potential role of Ileucyl-tRNA synthetase (IARS2) silencing in non-small cell lung cancer (NSCLC). The silencing of IARS2 in H1299 cells and A549 cells were performed by lentivirus encoding shRNAs. The efficiency of IARS2 silencing was detected by quantitative real time PCR and western blot. The effects of IARS2 silencing on cell growth, cell apoptosis, cell cycle and cell colony formation ability were assessed by cells counting, MTT assay, flow cytometer analysis and soft agar colony formation assay, respectively. Compared with negative control group, IARS2 was significantly knockdown by transfection with lentivirus encoding shRNA of IARS2. The IARS2 silencing significantly inhibited the cells proliferation and cells colony formation ability, induced cell cycle arrest at G1/S phase and promoted cell apoptosis. IARS2 silencing induced NSCLC cells growth inhibition, cell cycle arrest and promoted cell apoptosis. These results suggest that IARS2 may be a novel target for the treatment of NSCLC. PMID:26639235

  6. Hinokitiol Induces DNA Damage and Autophagy followed by Cell Cycle Arrest and Senescence in Gefitinib-Resistant Lung Adenocarcinoma Cells

    PubMed Central

    Li, Lan-Hui; Wu, Ping; Lee, Jen-Yi; Li, Pei-Rong; Hsieh, Wan-Yu; Ho, Chao-Chi; Ho, Chen-Lung; Chen, Wan-Jiun; Wang, Chien-Chun; Yen, Muh-Yong; Yang, Shun-Min; Chen, Huei-Wen

    2014-01-01

    Despite good initial responses, drug resistance and disease recurrence remain major issues for lung adenocarcinoma patients with epidermal growth factor receptor (EGFR) mutations taking EGFR-tyrosine kinase inhibitors (TKI). To discover new strategies to overcome this issue, we investigated 40 essential oils from plants indigenous to Taiwan as alternative treatments for a wide range of illnesses. Here, we found that hinokitiol, a natural monoterpenoid from the heartwood of Calocedrus formosana, exhibited potent anticancer effects. In this study, we demonstrated that hinokitiol inhibited the proliferation and colony formation ability of lung adenocarcinoma cells as well as the EGFR-TKI-resistant lines PC9-IR and H1975. Transcriptomic analysis and pathway prediction algorithms indicated that the main implicated pathways included DNA damage, autophagy, and cell cycle. Further investigations confirmed that in lung cancer cells, hinokitiol inhibited cell proliferation by inducing the p53-independent DNA damage response, autophagy (not apoptosis), S-phase cell cycle arrest, and senescence. Furthermore, hinokitiol inhibited the growth of xenograft tumors in association with DNA damage and autophagy but exhibited fewer effects on lung stromal fibroblasts. In summary, we demonstrated novel mechanisms by which hinokitiol, an essential oil extract, acted as a promising anticancer agent to overcome EGFR-TKI resistance in lung cancer cells via inducing DNA damage, autophagy, cell cycle arrest, and senescence in vitro and in vivo. PMID:25105411

  7. Mechanisms of G1 cell cycle arrest and apoptosis in myeloma cells induced by hybrid-compound histone deacetylase inhibitor

    SciTech Connect

    Fujii, Seiko; Okinaga, Toshinori; Ariyoshi, Wataru; Takahashi, Osamu; Iwanaga, Kenjiro; Nishino, Norikazu; Tominaga, Kazuhiro; Nishihara, Tatsuji

    2013-05-10

    Highlights: •Novel histone deacetylase inhibitor Ky-2, remarkably inhibits myeloma cell growth. •Ky-2 demonstrates no cytotoxicity against normal lymphocytic cells. •Ky-2 induces cell cycle arrest through the cell cycle-associated proteins. •Ky-2 induces Bcl-2-inhibitable apoptosis through a caspase-dependent cascade. -- Abstract: Objectives: Histone deacetylase (HDAC) inhibitors are new therapeutic agents, used to treat various types of malignant cancers. In the present study, we investigated the effects of Ky-2, a hybrid-compound HDAC inhibitor, on the growth of mouse myeloma cells. Materials and methods: Myeloma cells, HS-72, P3U1, and mouse normal cells were used in this study. Effect of HDAC inhibitors on cell viability was determined by WST-assay and trypan blue assay. Cell cycle was analyzed using flow cytometer. The expression of cell cycle regulatory and the apoptosis associated proteins were examined by Western blot analysis. Hoechst’s staining was used to detect apoptotic cells. Results: Our findings showed that Ky-2 decreased the levels of HDACs, while it enhanced acetylation of histone H3. Myeloma cell proliferation was inhibited by Ky-2 treatment. Interestingly, Ky-2 had no cytotoxic effects on mouse normal cells. Ky-2 treatment induced G1-phase cell cycle arrest and accumulation of a sub-G1 phase population, while Western blotting analysis revealed that expressions of the cell cycle-associated proteins were up-regulated. Also, Ky-2 enhanced the cleavage of caspase-9 and -3 in myeloma cells, followed by DNA fragmentation. In addition, Ky-2 was not found to induce apoptosis in bcl-2 overexpressing myeloma cells. Conclusion: These findings suggest that Ky-2 induces apoptosis via a caspase-dependent cascade and Bcl-2-inhibitable mechanism in myeloma cells.

  8. SIRT2 knockdown increases basal autophagy and prevents postslippage death by abnormally prolonging the mitotic arrest that is induced by microtubule inhibitors.

    PubMed

    Inoue, Toshiaki; Nakayama, Yuji; Li, Yanze; Matsumori, Haruka; Takahashi, Haruka; Kojima, Hirotada; Wanibuchi, Hideki; Katoh, Motonobu; Oshimura, Mitsuo

    2014-06-01

    Mitotic catastrophe, a form of cell death that occurs during mitosis and after mitotic slippage to a tetraploid state, plays important roles in the efficacy of cancer cell killing by microtubule inhibitors (MTIs). Prolonged mitotic arrest by the spindle assembly checkpoint is a well-known requirement for mitotic catastrophe, and thus for conferring sensitivity to MTIs. We previously reported that turning off spindle assembly checkpoint activation after a defined period of time is another requirement for efficient postslippage death from a tetraploid state, and we identified SIRT2, a member of the sirtuin protein family, as a regulator of this process. Here, we investigated whether SIRT2 regulates basal autophagy and whether, in that case, autophagy regulation by SIRT2 is required for postslippage death, by analogy with previous insights into SIRT1 functions in autophagy. We show, by combined knockdown of autophagy genes and SIRT2, that SIRT2 serves this function at least partially by suppressing basal autophagy levels. Notably, increased autophagy induced by rapamycin and mild starvation caused mitotic arrest for an abnormally long period of time in the presence of MTIs, and this was followed by delayed postslippage death, which was also observed in cells with SIRT2 knockdown. These results underscore a causal association among increased autophagy levels, mitotic arrest for an abnormally long period of time after exposure to MTIs, and resistance to MTIs. Although autophagy acts as a tumor suppressor mechanism, this study highlights its negative aspects, as increased autophagy may cause mitotic catastrophe malfunction. Thus, SIRT2 offers a novel target for tumor therapy. PMID:24712640

  9. Induction of apoptosis and cell cycle arrest in human HCC MHCC97H cells with Chrysanthemum indicum extract

    PubMed Central

    Li, Zong-Fang; Wang, Zhi-Dong; Ji, Yuan-Yuan; Zhang, Shu; Huang, Chen; Li, Jun; Xia, Xian-Ming

    2009-01-01

    AIM: To investigate the effects of Chrysanthemum indicum extract (CIE) on inhibition of proliferation and on apoptosis, and the underlying mechanisms, in a human hepatocellular carcinoma (HCC) MHCC97H cell line. METHODS: Viable rat hepatocytes and human endothelial ECV304 cells were examined by trypan blue exclusion and MTT assay, respectively, as normal controls. The proliferation of MHCC97H cells was determined by MTT assay. The cellular morphology of MHCC97H cells was observed by phase contrast microscopy. Flow cytometry was performed to analyze cell apoptosis with annexin V/propidium iodide (PI), mitochondrial membrane potential with rhodamine 123 and cell cycle with PI in MHCC97H cells. Apoptotic proteins such as cytochrome C, caspase-9, caspase-3 and cell cycle proteins, including P21 and CDK4, were measured by Western blotting. RESULTS: CIE inhibited proliferation of MHCC97H cells in a time- and dose-dependent manner without cytotoxicity in rat hepatocytes and human endothelial cells. CIE induced apoptosis of MHCC97H cells in a concentration-dependent manner, as determined by flow cytometry. The apoptosis was accompanied by a decrease in mitochondrial membrane potential, release of cytochrome C and activation of caspase-9 and caspase-3. CIE arrested the cell cycle in the S phase by increasing P21 and decreasing CDK4 protein expression. CONCLUSION: CIE exerted a significant apoptotic effect through a mitochondrial pathway and arrested the cell cycle by regulation of cell cycle-related proteins in MHCC97H cells without an effect on normal cells. The cancer-specific selectivity shown in this study suggests that the plant extract could be a promising novel treatment for human cancer. PMID:19777612

  10. Pirarubicin inhibits multidrug-resistant osteosarcoma cell proliferation through induction of G2/M phase cell cycle arrest

    PubMed Central

    Zheng, Shui-er; Xiong, Sang; Lin, Feng; Qiao, Guang-lei; Feng, Tao; Shen, Zan; Min, Da-liu; Zhang, Chun-ling; Yao, Yang

    2012-01-01

    Aim: Pirarubicin (THP) is recently found to be effective in treating patients with advanced, relapsed or recurrent high-grade osteosarcoma. In this study, the effects of THP on the multidrug-resistant (MDR) osteosarcoma cells were assessed, and the underlying mechanisms for the disruption of cell cycle kinetics by THP were explored. Methods: Human osteosarcoma cell line MG63 and human MDR osteosarcoma cell line MG63/DOX were tested. The cytotoxicity of drugs was examined using a cell proliferation assay with the Cell Counting Kit-8 (CCK-8). The distribution of cells across the cell cycle was determined with flow cytometry. The expression of cell cycle-regulated genes cyclin B1 and Cdc2 (CDK1), and the phosphorylated Cdc2 and Cdc25C was examined using Western blot analyses. Results: MG63/DOX cells were highly resistant to doxorubicin (ADM) and gemcitabine (GEM), but were sensitive or lowly resistant to THP, methotrexate (MTX) and cisplatin (DDP). Treatment of MG63/DOX cells with THP (200–1000 ng/mL) inhibited the cell proliferation in time- and concentration-dependent manners. THP (50–500 ng/mL) induced MG63/DOX cell cycle arrest at the G2/M phase in time- and concentration-dependent manners. Furthermore, the treatment of MG63/DOX cells with THP (200–1000 ng/mL) downregulated cyclin B1 expression, and decreased the phosphorylated Cdc2 at Thr161. Conversely, the treatment increased the phosphorylated Cdc2 at Thr14/Tyr15 and Cdc25C at Ser216, which led to a decrease in Cdc2-cyclin B1 activity. Conclusion: The cytotoxicity of THP to MG63/DOX cells may be in part due to its ability to arrest cell cycle progression at the G2/M phase, which supports the use of THP for managing patients with MDR osteosarcoma. PMID:22580740