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Sample records for altered pten expression

  1. Is STAT3 and PTEN Expression Altered in Canine Prostate Cancer?

    PubMed

    Lin, H-Y; Palmieri, C

    2016-01-01

    Signal transducer and activator of transcription 3 (STAT3) and phosphatase and tensin homologue (PTEN) are, respectively, an oncogene and tumour suppressor gene whose dysregulated expression in human prostate cancer is associated with increased malignancy and poor prognosis. Both markers were evaluated in 12 samples of canine benign prostatic hyperplasia (BPH) and 17 canine prostatic carcinomas (PCs) by immunohistochemistry, to understand their possible role in canine prostate carcinogenesis. STAT3 was expressed in 25% and 82.35% of BPH and PC, respectively, with a significantly higher number of STAT3-positive cells in malignant compared with hyperplastic lesions. Three PCs had occasional nuclear expression of STAT3. PTEN was expressed in BPH and PC with a similar distribution and percentage of positive cells; however, four PCs were PTEN negative. Solid PCs contained more STAT3-positive and fewer PTEN-positive cells compared with the other subtypes. A reduced number of PTEN-positive cells was observed in PCs with a high Gleason score (GS10), while no association was demonstrated between STAT3 expression and Gleason score. The data suggest that overexpression of STAT3 and downregulation of PTEN may be an important step in canine prostate carcinogenesis and both markers may be related to the histological subtypes of PC and the degree of differentiation of neoplastic cells.

  2. Altered PTEN, ATRX, CHGA, CHGB, and TP53 expression are associated with aggressive VHL-associated pancreatic neuroendocrine tumors.

    PubMed

    Weisbrod, Allison B; Zhang, Lisa; Jain, Meenu; Barak, Stephanie; Quezado, Martha M; Kebebew, Electron

    2013-06-01

    Von Hippel-Lindau (VHL) syndrome is an inherited cancer syndrome in which 8-17 % of germline mutation carriers develop pancreatic neuroendocrine tumors (PNETs). There is limited data on prognostic markers for PNETs other than Ki-67, which is included in the World Health Organization classification system. Recently, specific genes and pathways have been identified by whole exome sequencing which may be involved in the tumorigenesis of PNETs and may be markers of disease aggressiveness. The objective of this study was to identify molecular markers of aggressive disease in VHL-associated PNETs. The protein expression of eight genes (PTEN, CHGA, CHGB, ATRX, DAXX, CC-3, VEGF, and TP53) was analyzed in PNETs by immunohistochemistry and compared to clinical data, VHL genotype, functional imaging results, and pathologic findings. Subcellular distribution of phosphatase and tensin (PTEN), chromogranin A (CHGA), and alpha thalassemia/mental retardation syndrome X-linked (ATRX) were significantly different by WHO classifications (p ≤ 0.05). There was decreased PTEN nuclear to cytoplasmic ratio (p < 0.01) and decreased CHGA nuclear expression (p = 0.03) in malignant samples as compared to benign. Lower cytoplasmic chromogranin B (CHGB) expression (p = 0.03) was associated with malignant tumors and metastasis. Higher nuclear expression of PTEN was associated with VHL mutations in exon 3 (p = 0.04). Higher PTEN and CHGB expression was associated with higher FDG-PET avidity (p < 0.05). Cytoplasmic expression of CC-3 was associated with higher serum chromogranin A levels (ρ = 0.72, p = 0.02). Lastly, greater cytoplasmic expression of p53 was associated with metastasis. Our findings suggest that altered PTEN, ATRX, CHGA, and CHGB expression are associated with aggressive PNET phenotype in VHL and may serve as useful adjunct prognostic markers to Ki-67 in PNETs.

  3. High-grade fimbrial-ovarian carcinomas are unified by altered p53, PTEN and PAX2 expression.

    PubMed

    Roh, Michael H; Yassin, Yosuf; Miron, Alexander; Mehra, Karishma K; Mehrad, Mitra; Monte, Nicolas M; Mutter, George L; Nucci, Marisa R; Ning, Geng; Mckeon, Frank D; Hirsch, Michelle S; Wa, Xian; Crum, Christopher P

    2010-10-01

    High-grade endometrioid and serous carcinomas of the ovary and fallopian tube are responsible for the majority of cancer deaths and comprise a spectrum that includes early or localized (tubal intraepithelial carcinoma) and advanced (invasive or metastatic) disease. We subdivided a series of these tumors into three groups, (1) classic serous, (2) mixed serous and endometrioid and (3) endometrioid carcinomas and determined: (1) the frequencies of coexisting tubal intraepithelial carcinoma, (2) frequency of a dominant ovarian mass suggesting an ovarian origin and (3) immuno-localization of WT-1, p53, PTEN, PAX2 and p16(ink4). All tumors were analyzed for p53 mutations. Thirty six, 25 and 8% of groups 1-3 were associated with tubal intraepithelial carcinoma (P=0.09) and 34, 45 and 62% predominated in one ovary (P=0.028), respectively. Differences in frequencies of diffuse p53 immunostaining (85-93%), WT-1 (70-98%) and p16(ink4) positivity (69-75%) were not significant for all groups. Greater than 95% reduction in PAX2 and PTEN occurred in 67-75 and 5-12%, respectively; however, PAX2 and PTEN staining intensity, when present, was often heterogeneous, highlighting different tumor populations. PAX2 and PTEN expression were markedly reduced or absent in 12 of 12 and 4 of 12 tubal intraepithelial carcinomas. In summary, high-grade müllerian carcinomas share identical frequencies of altered or reduced expression of p53, PTEN and PAX2, all of which can be appreciated in tubal intraepithelial carcinomas. Because only a subset of these tumors appears to arise in the fallopian tube, attention to expression of these biomarkers in the ovary and other müllerian sites might facilitate the identification of other carcinogenic pathways. PAX2 and PTEN, in addition to p53 and p16(ink4), comprise a potentially important gene combination in high-grade pelvic carcinogenesis.

  4. Genetic alterations of PTEN in human melanoma.

    PubMed

    Aguissa-Touré, Almass-Houd; Li, Gang

    2012-05-01

    The PTEN gene is one of the most frequently inactivated tumor suppressor genes in sporadic cancers. Inactivating mutations and deletions of the PTEN gene are found in many types of cancers, including melanoma. However, the exact frequency of PTEN alteration in melanoma is unknown. In this study, we comprehensively reviewed 16 studies on PTEN genetic changes in melanoma cell lines and tumor biopsies. To date, 76 PTEN alterations have been reported in melanoma cell lines and 38 PTEN alterations in melanoma biopsies. The rate of PTEN alterations in melanoma cell lines, primary melanoma, and metastatic melanoma is 27.6, 7.3, and 15.2%, respectively. Three mutations were found in both melanoma cell lines and biopsies. These mutations are scattered throughout the gene, with the exception of exon 9. A mutational hot spot is found in exon 5, which encodes the phosphatase activity domain. Evidence is also presented to suggest that numerous homozygous deletions and missense variants exist in the PTEN transcript. Studying PTEN functions and implications of its mutations and other genes could provide insights into the precise nature of PTEN function in melanoma and additional targets for new therapeutic approaches. PMID:22076652

  5. Testosterone improves the transition of primary oocytes in artificial maturation eels (Anguilla japonica) by altering ovarian PTEN expression.

    PubMed

    Huang, Yung-Sen; Chen, Ya-Mei; Liao, Pei-Chi; Lee, Yan-Horn; Gwo, Jin-Chywan; Chen, Ming-Chyuan; Chang, Ching-Fong

    2012-06-01

    In mammals, androgens appear to enhance the development of primary ovarian follicles, but PI3K (phosphoinositide 3-kinases) pathway is well recognized as one of the critical pathways in early follicular development. Roles of the PI3K were revealed by deletion of PTEN (phosphatase and tensin homolog on chromosome 10). PTEN is demonstrated to play an important role in the early stage of follicle development. In the Japanese eel, two forms of PTEN have been cloned, but what their functions on the development of early ovarian follicles are still not clear. The natural blockage and inducible of ovarian development was a benefit to address this question in the eel. Testosterone (T) shows to ameliorate the early ovarian development in the eel. The aims of this study were to elucidate the two forms of PTEN by cellular and physiological criteria and to study the effects of T on the ovarian PTEN production in the exogenous pituitary extracts-stimulated eel. Our results suggested that two forms of PTEN are existing in the Japanese eel, and eel ovarian development corresponded to the decrease in ovarian PTEN expression, vice versa. In addition, the supplement of T on eel early ovarian development can be attributed to its PTEN inhibitor role.

  6. Effects of PTEN gene alteration in patients with gallbladder cancer.

    PubMed

    Ali, Asgar; Mishra, Pramod Kumar; Sharma, Sadhana; Arora, Asit; Saluja, Sundeep Singh

    2015-12-01

    Gallbladder cancer (GBC) is an aggressive malignancy usually diagnosed in an advanced stage. We investigated the effects of alterations of the phosphatase and tensin homologue (PTEN) gene on the occurrence and development of GBC, which has not been previously reported. A total 141 cases of GBC were analyzed for mutation, expression, and methylation across the nine exons of the PTEN gene. DNA sequencing methods were applied for mutation detection, whereas protein expression and methylation status were evaluated by immunohistochemical and methylation-specific PCR analysis, respectively. Novel PTEN mutations were observed in 6.3% of cases (9/141), and they included two silent mutations. In mutant cases, according to changes in codons, the respective amino acid sequences were also changed, which caused of proteins. A high percentage (72%) of loss of protein expression was observed more often in cases than in control samples. Interestingly, all nine cases with mutations showed loss of PTEN expression, whereas four of these nine cases showed positive promoter methylation. Hypermethylation was significantly more common in older patients than in younger ones (P<0.02). These findings suggest that PTEN mutations and inactivation may play an important role in the development and progression of gallbladder carcinoma. PMID:26586294

  7. PTEN

    PubMed Central

    Garcia-Junco-Clemente, Pablo; Golshani, Peyman

    2014-01-01

    PTEN (phosphatase and tensin homolog on chromosome ten) is a dual protein/lipid phosphatase that dephosphorylates PIP3, thereby inhibiting the AKT/mTOR pathway. This inhibition ultimately decreases protein translation, cell proliferation and cell growth. In the central nervous system, inhibition of PTEN leads to increased stem cell proliferation, somatic, dendritic and axonal growth, accelerated spine maturation, diminished synaptic plasticity, and altered intrinsic excitability. In agreement with these findings, patients carrying single-copy inactivating mutations of PTEN suffer from autism, macrocephaly, mental retardation, and epilepsy.1-9 Understanding the mechanisms through which PTEN modulates the structure, function, and plasticity of cortical networks is a major focus of study. Preventing and reversing the changes induced by loss of Pten in model animals will pave the way for treatments in humans. PMID:24778766

  8. PTEN protein expression correlates with PTEN gene molecular changes but not with VEGF expression in astrocytomas.

    PubMed

    Idoate, M A; Soria, E; Lozano, M D; Sola, J J; Panizo, A; de Alava, E; Manrique, M; Pardo-Mindán, F J

    2003-09-01

    PTEN gene (10q23) is a relevant tumor suppressor gene whose protein is a phosphatase involved in the control of angiogenesis of some tumors including astrocytomas. There are no studies correlating molecular changes of PTEN and the immunohistochemical expression of its protein (pPTEN) with the expression of vascular endothelial growth factor (VEGF) in astrocytomas. Fifty-six surgically resected brain gliomas, 10 grade 2, 16 grade 3, and 30 grade 4, were studied by a combined approach, consisting of (1) PCR analysis using four microsatellite markers against the PTEN gene region (10q23), (2) the FISH technique to test chromosome 10 using a pericentromeric probe, and (3) immunohistochemical evaluation of pPTEN and VEGF. Loss of heterozygosity (LOH) of PTEN was observed in 10% of fibrillary grade 2 astrocytomas and all gemistocytic ones. In high-grade tumors, LOH was more frequent in grade 4 than in grade 3 (> or =2 loci deleted, 83% and 56%, respectively). Monosomy for chromosome 10 was observed especially in high-grade tumors (6% of grade 3 and 50% of grade 4) and in 20% of grade 2 tumors, corresponding to gemistocytic astrocytomas. Results with both antibodies against PTEN were concordant: loss of cytoplasmic immunoreactivity was frequently observed according to homogeneous or heterogeneous patterns in 70% and 50% of grades 4 and 3, respectively, but not in grade 2. Immunonegativity of pPTEN was associated with PTEN gene deletion (> or =2 loci deleted) (P = 0.04) but not with monosomy. Cytoplasmic immunoreactivity against VEGF was observed in high-grade and in gemistocytic astrocytomas, but not in conventional grade 2 tumors. Tumor expression of pPTEN was not associated with immunoreactivity against VEGF when the same areas were considered. In conclusion, loss of PTEN expression is frequent in high-grade astrocytomas, but not in grade 2 tumors, and correlates with PTEN deletion and loss of chromosome 10. PTEN immunoreactivity does not correlate with VEGF expression

  9. Apoptotic effects of signal transduction inhibitors on human tumor cells with different PTEN expression.

    PubMed

    Pfeiler, Georg; Horn, Felicitas; Lattrich, Claus; Klappenberger, Stefanie; Ortmann, Olaf; Treeck, Oliver

    2007-11-01

    An important mechanism of antitumoral targeted therapies is the induction of apoptosis in tumor cells. Tamoxifen and trastuzumab (Herceptin), respectively, are able to trigger apoptosis in human breast cancer cells. But, frequently altered apoptotic signal cascades, for instance through PTEN mutations, help tumor cells to escape antitumoral therapy. We studied to what extent the apoptotic effect of signal-transduction inhibitors is dependent on PTEN expression. PTEN expression was analysed by Western blot analysis in tumor cell lines of the breast (BT-474, MCF-7, MDA-MB-231), ovary (BG-1, SK-OV-3) and endometrium (Ishikawa, HEC-1A). Apoptotic effects of tamoxifen, trastuzumab, ZD1839 (Iressa) and different mitogen-activated protein kinase (MAP) inhibitors were measured after 24 h of treatment. Cellular apoptosis was determined by the detection of cytoplasmic histone-DNA complexes. The tested tumor cell lines exhibited a different PTEN expression, ranging from a high expression (ovarian cancer cell line BG-1 and BT-474 breast cancer cells) to a total absence of PTEN expression (endometrial Ishikawa cells). The apoptotic effect of receptor-targeting drugs (tamoxifen, trastuzumab, ZD1839) was dependent both on receptor expression and PTEN expression. When cells were treated with MAPK inhibitors, no correlation between PTEN expression and the apoptosis rate was observed. Our data underline the importance of PTEN expression regarding the induction of apoptosis through various targeted therapies.

  10. PTEN knockdown alters dendritic spine/protrusion morphology, not density

    PubMed Central

    Haws, Michael E.; Jaramillo, Thomas C.; Espinosa-Becerra, Felipe; Widman, Allie; Stuber, Garret D.; Sparta, Dennis R.; Tye, Kay M.; Russo, Scott J.; Parada, Luis F.; Kaplitt, Michael; Bonci, Antonello; Powell, Craig M.

    2014-01-01

    Mutations in phosphatase and tensin homolog deleted on chromosome ten (PTEN) are implicated in neuropsychiatric disorders including autism. Previous studies report that PTEN knockdown in neurons in vivo leads to increased spine density and synaptic activity. To better characterize synaptic changes in neurons lacking PTEN, we examined the effects of shRNA knockdown of PTEN in basolateral amygdala neurons on synaptic spine density and morphology using fluorescent dye confocal imaging. Contrary to previous studies in dentate gyrus, we find that knockdown of PTEN in basolateral amygdala leads to a significant decrease in total spine density in distal dendrites. Curiously, this decreased spine density is associated with increased miniature excitatory post-synaptic current frequency and amplitude, suggesting an increase in number and function of mature spines. These seemingly contradictory findings were reconciled by spine morphology analysis demonstrating increased mushroom spine density and size with correspondingly decreased thin protrusion density at more distal segments. The same analysis of PTEN conditional deletion in dentate gyrus demonstrated that loss of PTEN does not significantly alter total density of dendritic protrusions in the dentate gyrus, but does decrease thin protrusion density and increases density of more mature mushroom spines. These findings suggest that, contrary to previous reports, PTEN knockdown may not induce de novo spinogenesis, but instead may increase synaptic activity by inducing morphological and functional maturation of spines. Furthermore, behavioral analysis of basolateral amygdala PTEN knockdown suggests that these changes limited only to the basolateral amygdala complex may not be sufficient to induce increased anxiety-related behaviors. PMID:24264880

  11. Decrease in PTEN and increase in Akt expression and neuron size in aged rat spinal cord

    PubMed Central

    Rodrigues De Amorim, Miguel Augusto; Garcia-Segura, Luis Miguel; Goya, Rodolfo Gustavo; Portiansky, Enrique Leo

    2010-01-01

    PTEN is a tumor suppressor gene known to play an important role in the regulation of cell size. In this study we compared PTEN expression in the spinal cord of young (5 mo.) versus aged (32 mo.) female rats and correlated them with alterations in neuron size and morphology in the same animals. Total and phosphorylated PTEN (pPTEN) as well as its downstream target phosphorylated Akt (pAkt) were assessed by western blotting. Spinal cord neurons were morphometrically characterized. Total PTEN, pPTEN and total Akt expression were significantly higher in young rats than in aged animals. Expression of pAkt was stronger in aged animals. A significant increase in neuronal size was observed in large motoneurons of aged as compared with young rats. Our data show that in the spinal cord of rats, neuronal PTEN expression diminishes with advanced age while neuronal size increases. These results suggest that in the spinal cord, an age-related reduction in PTEN and increase of pAkt expression may be involved in the progressive enlargement of neurons. PMID:20347952

  12. Global DNA methylation and PTEN hypermethylation alterations in lung tissues from human silicosis

    PubMed Central

    Zhang, Xianan; Jia, Xiaowei; Mei, Liangying; Zheng, Min; Yu, Chen

    2016-01-01

    Background Silicosis is a respiratory disease caused by long-term silica dust exposure. Our previous study has demonstrated that silica mediates the activation of phosphatidylinositol 3-kinase (PI3K)/phosphatase and tensin homolog deleted on chromosome 10 (PTEN)/serine or threonine kinase (AKT)/mitogen-activated protein kinases (MAPK)/AP-1 pathway in human embryo lung fibroblasts (HELFs). The purpose of this study is to identify genome-wide aberrant DNA methylation profiling in lung tissues from silicosis patients. Methods We performed Illumina Human Methylation 450K Beadchip arrays to investigate the methylation alteration in formalin-fixed, paraffin-embedded (FFPE) lung specimens, immunohistochemistry to detect the level of c-Jun and PTEN proteins; methylation specific PCR (MS-PCR) to identify PTEN and c-Jun promoter methylation in HELFs. Results We found 86,770 CpG sites and 79,660 CpG sites significantly differed in methylation status in early-stage and advanced-stage compared with GEO normal lung methylation data. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed the methylated status of MAPK signaling pathway was considered changed. The number of PTEN and c-Jun CpG promoter methylated-sites were increased in advanced-stage. Early-stage showed the positive expression of c-Jun and PTEN protein and negative or mild expression in advanced-stage. PTEN promoter was no differentially methylated and c-Jun promoter differed at 12 and 24 h in HELFs. Conclusions Abnormal DNA methylation on genome-scale was implicated in silicosis, and PTEN promoter hypermethylation might be associated with decrease of PTEN protein. PMID:27621875

  13. Global DNA methylation and PTEN hypermethylation alterations in lung tissues from human silicosis

    PubMed Central

    Zhang, Xianan; Jia, Xiaowei; Mei, Liangying; Zheng, Min; Yu, Chen

    2016-01-01

    Background Silicosis is a respiratory disease caused by long-term silica dust exposure. Our previous study has demonstrated that silica mediates the activation of phosphatidylinositol 3-kinase (PI3K)/phosphatase and tensin homolog deleted on chromosome 10 (PTEN)/serine or threonine kinase (AKT)/mitogen-activated protein kinases (MAPK)/AP-1 pathway in human embryo lung fibroblasts (HELFs). The purpose of this study is to identify genome-wide aberrant DNA methylation profiling in lung tissues from silicosis patients. Methods We performed Illumina Human Methylation 450K Beadchip arrays to investigate the methylation alteration in formalin-fixed, paraffin-embedded (FFPE) lung specimens, immunohistochemistry to detect the level of c-Jun and PTEN proteins; methylation specific PCR (MS-PCR) to identify PTEN and c-Jun promoter methylation in HELFs. Results We found 86,770 CpG sites and 79,660 CpG sites significantly differed in methylation status in early-stage and advanced-stage compared with GEO normal lung methylation data. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed the methylated status of MAPK signaling pathway was considered changed. The number of PTEN and c-Jun CpG promoter methylated-sites were increased in advanced-stage. Early-stage showed the positive expression of c-Jun and PTEN protein and negative or mild expression in advanced-stage. PTEN promoter was no differentially methylated and c-Jun promoter differed at 12 and 24 h in HELFs. Conclusions Abnormal DNA methylation on genome-scale was implicated in silicosis, and PTEN promoter hypermethylation might be associated with decrease of PTEN protein.

  14. PI3K isoform dependence of PTEN-deficient tumors can be altered by the genetic context.

    PubMed

    Schmit, Fabienne; Utermark, Tamara; Zhang, Sen; Wang, Qi; Von, Thanh; Roberts, Thomas M; Zhao, Jean J

    2014-04-29

    There has been increasing interest in the use of isoform-selective inhibitors of phosphatidylinositide-3-kinase (PI3K) in cancer therapy. Using conditional deletion of the p110 catalytic isoforms of PI3K to predict sensitivity of cancer types to such inhibitors, we and others have demonstrated that tumors deficient of the phosphatase and tensin homolog (PTEN) are often dependent on the p110β isoform of PI3K. Because human cancers usually arise due to multiple genetic events, determining whether other genetic alterations might alter the p110 isoform requirements of PTEN-null tumors becomes a critical question. To investigate further the roles of p110 isoforms in PTEN-deficient tumors, we used a mouse model of ovarian endometrioid adenocarcinoma driven by concomitant activation of the rat sarcoma protein Kras, which is known to activate p110α, and loss of PTEN. In this model, ablation of p110β had no effect on tumor growth, whereas p110α ablation blocked tumor formation. Because ablation of PTEN alone is often p110β dependent, we wondered if the same held true in the ovary. Because PTEN loss alone in the ovary did not result in tumor formation, we tested PI3K isoform dependence in ovarian surface epithelium (OSE) cells deficient in both PTEN and p53. These cells were indeed p110β dependent, whereas OSEs expressing activated Kras with or without PTEN loss were p110α dependent. Furthermore, isoform-selective inhibitors showed a similar pattern of the isoform dependence in established Kras(G12D)/PTEN-deficient tumors. Taken together, our data suggest that, whereas in some tissues PTEN-null tumors appear to inherently depend on p110β, the p110 isoform reliance of PTEN-deficient tumors may be altered by concurrent mutations that activate p110α.

  15. NEDD4-1 and PTEN expression in keloid scarring.

    PubMed

    Sang, P F; Wang, H; Wang, M; Hu, C; Zhang, J S; Li, X J; Zhu, F

    2015-01-01

    Keloid scarring remains a major problem in plastic surgery. The aim of this study was to determine the expression of the PTEN tumor suppressor and NEDD4-1 genes in keloid tissue and explore their effect on the formation of such scarring. Twenty keloid patients were enrolled in the study and underwent surgical removal of keloid tissue. No patient had received chemotherapy and/or radiotherapy prior to treatment. PTEN and NEDD4-1 mRNA expression was detected by reverse transcription PCR, while PTEN protein expression was assessed using immunohistochemistry. Our results showed that levels of PTEN were significantly diminished in keloid samples (P < 0.05), whereas those of NEDD4-1 did not significantly differ between keloid tissue and normal skin (P > 0.05). Furthermore, we found that NEDD4-1 expression is high and inversely correlated with that of PTEN in keloids. Our results suggest that the PTEN/PI3K/AKT pathway may play an important role in keloid formation and reduces PTEN expression in such tissue. Finally, although NEDD4-1 has previously been identified as a factor in keloid susceptibility, and the protein for which it encodes is known to degrade PTEN by catalyzing its polyubiquitylation, the detailed mechanism behind its involvement in keloid formation needs to be further studied. PMID:26535660

  16. Relationship between PTEN, DNA mismatch repair, and tumor histotype in endometrial carcinoma: retained positive expression of PTEN preferentially identifies sporadic non-endometrioid carcinomas.

    PubMed

    Djordjevic, Bojana; Barkoh, Bedia A; Luthra, Rajyalakshmi; Broaddus, Russell R

    2013-10-01

    Loss of PTEN (phosphatase and tensin homolog) expression and microsatellite instability are two of the more common molecular alterations in endometrial carcinoma. From the published literature, it is controversial as to whether there is a relationship between these different molecular mechanisms. Therefore, a cohort of 187 pure endometrioid and non-endometrioid endometrial carcinomas, carefully characterized as to clinical and pathological features, was examined for PTEN sequence abnormalities and the immunohistochemical expression of PTEN and the DNA mismatch repair proteins MLH1, MSH2, MSH6, and PMS2. MLH1 methylation analysis was performed when tumors had loss of MLH1 protein. Mismatch repair protein loss was more frequent in endometrioid carcinomas compared with non-endometrioid carcinomas, a difference primarily attributable to the presence of MLH1 methylation in a greater proportion of endometrioid tumors. Among the non-endometrioid group, mixed endometrioid/non-endometrioid carcinomas were the histotype that most commonly had loss of a mismatch repair protein. In endometrioid tumors, the frequency of PTEN loss measured by immunohistochemistry and mutation did not differ significantly between the mismatch repair protein intact or mismatch repair protein loss groups, suggesting that PTEN loss is independent of mismatch protein repair status in this group. However, in non-endometrioid carcinomas, both intact positive PTEN immunohistochemical expression and PTEN wild type were highly associated with retained positive expression of mismatch repair proteins in the tumor. Relevant to screening endometrial cancers for Lynch Syndrome, an initial PTEN immunohistochemistry determination may be able to replace the use of four mismatch repair immunohistochemical markers in 63% of patients with non-endometrioid endometrial carcinoma. Therefore, PTEN immunohistochemistry, in combination with tumor histotype, is a useful adjunct in the clinical evaluation of endometrial

  17. PTEN expression in PTEN-null leukaemic T cell lines leads to reduced proliferation via slowed cell cycle progression.

    PubMed

    Seminario, Maria-Cristina; Precht, Patricia; Wersto, Robert P; Gorospe, Myriam; Wange, Ronald L

    2003-11-01

    The balance of activities between the proto-oncogene phosphoinositide 3-kinase (PI3K) and the tumour suppressor gene PTEN has been shown to affect cellular growth and proliferation, as well as tumorigenesis. Previously, PTEN expression in the PTEN-null Jurkat T cell leukaemia line was shown to cause reduced proliferation without cell cycle arrest. Here, we further these investigations by determining the basis for this phenomenon. By BrdU pulse-chase and cell cycle arrest and release assays, we find that PTEN expression reduced proliferation by slowing progression through all phases of the cell cycle. This was associated with reduced levels of cyclins A, B1 and B2, cdk4, and cdc25A and increased p27KIP1 expression. Apoptosis played no role in the antiproliferative effect of PTEN, since only marginal increases in the rate of apoptosis were detected upon PTEN expression, and inhibitors of effector caspases did not restore proliferative capacity. Active Akt blocked the antiproliferative effects of PTEN, indicating that PTEN mediates its effects through conventional PI3K-linked signalling pathways. Similar results were obtained from a different PTEN-null leukaemia T cell line, CEM. Together, these results show that PTEN expression in leukaemic T cells leads to reduced proliferation via an apoptosis-independent mechanism involving slower passage through the cell cycle.

  18. Loss of NDRG2 expression activates PI3K-AKT signalling via PTEN phosphorylation in ATLL and other cancers

    PubMed Central

    Nakahata, Shingo; Ichikawa, Tomonaga; Maneesaay, Phudit; Saito, Yusuke; Nagai, Kentaro; Tamura, Tomohiro; Manachai, Nawin; Yamakawa, Norio; Hamasaki, Makoto; Kitabayashi, Issay; Arai, Yasuhito; Kanai, Yae; Taki, Tomohiko; Abe, Takaya; Kiyonari, Hiroshi; Shimoda, Kazuya; Ohshima, Koichi; Horii, Akira; Shima, Hiroshi; Taniwaki, Masafumi; Yamaguchi, Ryoji; Morishita, Kazuhiro

    2014-01-01

    Constitutive phosphatidylinositol 3-kinase (PI3K)-AKT activation has a causal role in adult T-cell leukaemia-lymphoma (ATLL) and other cancers. ATLL cells do not harbour genetic alterations in PTEN and PI3KCA but express high levels of PTEN that is highly phosphorylated at its C-terminal tail. Here we report a mechanism for the N-myc downstream-regulated gene 2 (NDRG2)-dependent regulation of PTEN phosphatase activity via the dephosphorylation of PTEN at the Ser380, Thr382 and Thr383 cluster within the C-terminal tail. We show that NDRG2 is a PTEN-binding protein that recruits protein phosphatase 2A (PP2A) to PTEN. The expression of NDRG2 is frequently downregulated in ATLL, resulting in enhanced phosphorylation of PTEN at the Ser380/Thr382/Thr383 cluster and enhanced activation of the PI3K-AKT pathway. Given the high incidence of T-cell lymphoma and other cancers in NDRG2-deficient mice, PI3K-AKT activation via enhanced PTEN phosphorylation may be critical for the development of cancer. PMID:24569712

  19. [Pten gene expression in the endometrial mucosa].

    PubMed

    Bakiewicz, Anna; Goździk, Jarosław; Sporny, Stanisław

    2006-04-01

    The opinions about the causes of the endometrial carcinoma have changed since 1995, due to molecular biology progress. The findings concerning the recently discovered suppressor PTEN gene localized on the chromosome 10 -10q23.3, the product of which is a specific phosphatase are especially valuable. The loss of the gene function is directly linked with the genesis and progression of endometrial carcinoma, as well as cancers of other tissues and organs, including thyroid, breast, ovary, prostate or skin. Immunohistochemical studies with the use of the 6H2.1 antibody directed against the protein coded by the PTEN gene indicate that the protein cannot be found in more than half of the patients with endometrial carcinoma and its precursor--EIN. Mutations of the PTEN gene have also been detected in many young women with normal microscopic structure of the endometrial mucosa. Thus, a test for the absence of the PTEN gene product in the endometrial cells may be used for precise identification of early stages of carcinogenesis.

  20. Nongenomic Mechanisms of PTEN Regulation

    PubMed Central

    Fata, Jimmie E.; Debnath, Shawon; Jenkins, Edmund C.; Fournier, Marcia V.

    2012-01-01

    A large amount of data supports the view that PTEN is a bona fide tumor suppressor gene. However, recent evidence suggests that derailment of cellular localization and expression levels of functional nonmutated PTEN is a determining force in inducing abnormal cellular and tissue outcomes. As the cellular mechanisms that regulate normal PTEN enzymatic activity resolve, it is evident that deregulation of these mechanisms can alter cellular processes and tissue architecture and ultimately lead to oncogenic transformation. Here we discuss PTEN ubiquitination, PTEN complex formation with components of the adherens junction, PTEN nuclear localization, and microRNA regulation of PTEN as essential regulatory mechanisms that determine PTEN function independent of gene mutations and epigenetic events. PMID:22536248

  1. The mechanism involved in the loss of PTEN expression in NSCLC tumor cells

    SciTech Connect

    Li, Gang; Zhao, Jingfeng; Peng, Xianjing; Liang, Jian; Deng, Xin; Chen, Yuxiang

    2012-02-17

    Highlights: Black-Right-Pointing-Pointer Radiation stimulates PTEN reexpression in NSCLC independent of p53 activation. Black-Right-Pointing-Pointer PTEN reexpression is mediated by miR-29b overexpression. Black-Right-Pointing-Pointer miR-29b regulates Dnmts expression in NSCLC tumor cells. Black-Right-Pointing-Pointer Target therapy could be established by overexpressing miR-29b expression. -- Abstract: Loss of PTEN expression is observed in most non-small cell lung cancers (NSCLC). However, the mechanism by which PTEN expression is regulated in NSCLC has not been fully elucidated. In this study, we investigated the role of DNA methyltransferases (Dnmts), microRNA-29b (miR-29b), and anti-miR-29b inhibitor in PTEN promoter methylation and PTEN gene expression in H358 NSCLC cells in vitro and in vivo. PTEN mRNA was measured by RT-PCR. PTEN and Dnmts protein levels were measured by Western blot. miR-29b expression was detected by Northern blot. A xenograft H358 tumor mouse model was established by subcutaneously inoculating H358 cells into the right hind limbs of nude mice. We found that radiation induced cell apoptosis and hypomethylation in PTEN promoter, PTEN and miR-29b expression, and downregulation of Dnmt1, 3a and 3b expression in H358 tumor cells. The effect of radiation on gene expression and apoptosis was blocked by anti-miR-29b inhibitor. In the xenograft H358 tumor model, anti-miR-29b inhibitor reversed radiation-induced tumor growth delay, PTEN reexpression and downregulation of Dnmts expression. Our study suggested that miR-29b is an upstream molecule of PTEN. miR-29b regulates PTEN gene expression through downregulating Dnmts expression and subsequently induces hypomethylation in PTEN promoter. Targeting therapy could be established in NSCLC by upregulating miR-29b expression.

  2. PTEN overexpression improves cisplatin-resistance of human ovarian cancer cells through upregulating KRT10 expression

    SciTech Connect

    Wu, Huijuan; Wang, Ke; Liu, Wenxin; Hao, Quan

    2014-02-07

    Highlights: • Overexpression of PTEN enhanced the sensitivity of C13K cells to cisplatin. • KRT10 is a downstream molecule of PTEN involved in the resistance-reversing effect. • Overexpression of KRT10 enhanced the chemosensitivity of C13K cells to cisplatin. - Abstract: Multi-drug resistance (MDR) is a common cause of the failure of chemotherapy in ovarian cancer. PTEN, a tumor suppressor gene, has been demonstrated to be able to reverse cisplatin-resistance in ovarian cancer cell line C13K. However, the downstream molecules of PTEN involved in the resistance-reversing effect have not been completely clarified. Therefore, we screened the downstream molecules of PTEN and studied their interactions in C13K ovarian cancer cells using a 3D culture model. Firstly, we constructed an ovarian cancer cell line stably expressing PTEN, C13K/PTEN. MTT assay showed that overexpression of PTEN enhanced the sensitivity of C13K cells to cisplatin, but not to paclitaxel. Then we examined the differently expressed proteins that interacted with PTEN in C13K/PTEN cells with or without cisplatin treatment by co-immunoprecipitation. KRT10 was identified as a differently expressed protein in cisplatin-treated C13K/PTEN cells. Further study confirmed that cisplatin could induce upregulation of KRT10 mRNA and protein in C13K/PTEN cells and there was a directly interaction between KRT10 and PTEN. Forced expression of KRT10 in C13K cells also enhanced cisplatin-induced proliferation inhibition and apoptosis of C13K cells. In addition, KRT10 siRNA blocked cisplatin-induced proliferation inhibition of C13K/PTEN cells. In conclusion, our data demonstrate that KRT10 is a downstream molecule of PTEN which improves cisplatin-resistance of ovarian cancer and forced KRT10 overexpression may also act as a therapeutic method for overcoming MDR in ovarian cancer.

  3. MMAC/PTEN gene expression in endometrial cancer: RT-PCR studies.

    PubMed

    Sobczuk, Anna; Smolarz, Beata; Romanowicz-Makowska, Hanna; Pertyński, Tomasz

    2006-01-01

    Mutations in the MMAC/PTEN (phosphatase and tensin homologue deleted on chromosome 10) gene are documented in cancers of the breast, prostate, ovary, colon, melanoma, glioblastoma, lymphoma and endometrium. In the present work MMAC/PTEN gene expression in women with endometrial adenocarcinoma (n=70) in RNA samples obtained from cancer tissue were investigated. Control DNA was obtained from 68 normal endometrial tissue. The MMAC/PTEN expression was determined by RT-PCR analysis. The expression of MMAC/PTEN gene in endometrial adenocarcinoma cases was significantly reduced compared to the expression in the normal samples (P < 0.05). Furthermore the significant difference (P < 0.05) was observed between the expression of MMAC/PTEN in stage III versus lower stages of endometrial cancer. The results support the hypothesis that the MMAC/PTEN gene expression may be associated with the incidence of endometrial cancer.

  4. Modulation of specific protein expression levels by PTEN: identification of AKAP121, DHFR, G3BP, Rap1, and RCC1 as potential targets of PTEN.

    PubMed

    Huang, Yanping; Wernyj, Roman P; Norton, Darrell D; Precht, Patricia; Seminario, Maria-Cristina; Wange, Ronald L

    2005-05-26

    The tumor suppressor PTEN is mutated in a high percentage of human cancers, and is implicated in pathways regulating cell growth, proliferation, survival, and migration. Despite significant advances, our understanding of its mechanisms of action remains incomplete. We have used a high-throughput proteomic immunoblotting approach to identify proteins whose expression levels are modulated by PTEN. Out of over 800 proteins screened, 22 proteins showed significant changes in expression. Five proteins that exhibited two-fold or greater changes in expression level were further characterized. AKAP121 and G3BP expression was reduced, while dihydrofolate reductase (DHFR), Rap1 and RCC1 expression was elevated in response to PTEN expression in a PTEN-null T-cell leukemia line. The phosphatase activity of PTEN was required for these effects. However, direct inhibition of PI-3 Kinase could mimic PTEN in modulating expression of DHFR, G3BP, Rap1 and RCC1, but not AKAP121. Real-time PCR showed that the effects of PTEN were primarily post-transcriptional, and would not have been revealed by mRNA-based screens. We conclude from these data that PTEN can modulate the expression level of a number of different proteins. The identified proteins have the potential to serve as previously unrecognized effectors of PTEN, and suggest the existence of additional complexity in the modes by which PTEN can regulate cellular biology.

  5. PTEN's regulation of VEGF and VEGFR1 expression and its clinical significance in myeloid leukemia.

    PubMed

    Zhiyong, Cheng; Wentong, Liang; Xiaoyang, Yang; Ling, Pan

    2012-06-01

    Phosphatase and tensin homolog (PTEN) acts as a novel tumor suppressor gene. PTEN protein plays an important role in regulating proliferation, apoptosis, invasion, and migration of many cancer cells. PTEN also modulates angiogenesis mediated by vascular endothelial growth factor (VEGF) via down-regulating PI3K/Akt pathway in many solid tumors. However, the effects of PTEN on VEGF and VEGFR1 (FLT1)-mediated angiogenesis, migration, invasion of leukemia cells, and its clinical significance are still unknown in myeloid leukemia. Therefore, we investigated the effect of PTEN on PI3K/Akt and VEGF/FLT1 pathways by transfecting wild-type PTEN gene to induce high expression of wild-type PTEN gene and protein in chronic myelogenous leukemia cell line K562 cells. We also observed the correlation between the expression levels of PTEN and VEGF/FLT1 and its clinical significance in myeloid leukemia patients. We found that the expression reconstitution of wild-type PTEN had significant effect on inhibiting proliferation, migration, and invasion abilities of K562 cells via down-regulation of Akt phosphorylation and inhibition of VEGF/FLT1 expression. In myeloid leukemia patients, a negative correlation was found between the expression level of PTEN mRNA and that of VEGF and FLT1 mRNA. Down-regulation of PTEN expression accompanied by up-regulation of VEGF and FLT1 mRNA indicated a higher tendency of extramedullary disease in acute myeloid leukemia patients. In conclusion, PTEN could modulate the function of VEGF/VEGFR signaling pathway down-regulation of Akt phosphorylation and that PTEN would be a candidate target to be addressed for inhibiting angiogenesis along with the treatment of myeloid leukemia.

  6. Subtle variations in Pten dose determine cancer susceptibility.

    PubMed

    Alimonti, Andrea; Carracedo, Arkaitz; Clohessy, John G; Trotman, Lloyd C; Nardella, Caterina; Egia, Ainara; Salmena, Leonardo; Sampieri, Katia; Haveman, William J; Brogi, Edi; Richardson, Andrea L; Zhang, Jiangwen; Pandolfi, Pier Paolo

    2010-05-01

    Cancer susceptibility has been attributed to at least one heterozygous genetic alteration in a tumor suppressor gene (TSG). It has been hypothesized that subtle variations in TSG expression can promote cancer development. However, this hypothesis has not yet been definitively supported in vivo. Pten is a TSG frequently lost in human cancer and mutated in inherited cancer-predisposition syndromes. Here we analyze Pten hypermorphic mice (Pten(hy/+)), expressing 80% normal levels of Pten. Pten(hy/+) mice develop a spectrum of tumors, with breast tumors occurring at the highest penetrance. All breast tumors analyzed here retained two intact copies of Pten and maintained Pten levels above heterozygosity. Notably, subtle downregulation of Pten altered the steady-state biology of the mammary tissues and the expression profiles of genes involved in cancer cell proliferation. We present an alterative working model for cancer development in which subtle reductions in the dose of TSGs predispose to tumorigenesis in a tissue-specific manner.

  7. Abnormal expression of PTEN and PIK3CA in pemetrexed-resistant human pancreatic cancer cell line Patu8988.

    PubMed

    Shi, X; Gu, H T; Lin, S B; Zhang, Y; Yang, J; Qian, C J

    2016-01-01

    The aim of this study was to investigate the expression of PTEN and PIK3CA in the pemetrexed-resistant human pancreatic cancer cell line Patu8988, and to evaluate their effects on the biological behavior of pancreatic cancer cells. PTEN and PIK3CA gene and protein expressions were detected by reverse transcriptase polymerase chain reaction (RT-PCR) and western blot, respectively, in a pemetrexed-resistant pancreatic cancer cell line and in the parent strain of the pancreatic cancer cells. The discrepancies between the two types of cell lines were detected by a transwell test. RT-PCR and western blot analyses revealed that PTEN and PIK3CA were overexpressed in the pemetrexed-resistant pancreatic cancer cell line. PTEN and PIK3CA were shown to be upregulated by 89 and 76% (western blot), respectively, in the pemetrexed-resistant cell line, compared to the normal pancreatic cancer cell line. The migratory and invasive abilities of the pemetrexed-resistant pancreatic cancer cell were significantly reduced compared to those of the parent strain (P < 0.05; transwell assay). Both PTEN and PIK3CA expression was abnormally enhanced in the pemetrexed-resistant cell line Patu8988; the co-existence of high levels of PTEN and PIK3CA in the pemetrexed-resistant pancreatic cancer line cells induced a significant decrease in their migratory and invasive capacities. This suggested that the mechanism of pemetrexed resistant may be affected by PTEN and PIK3CA, and that these may alter the biological behavior of cancer cells. PMID:27525871

  8. Adenovirus-mediated co-expression of ING4 and PTEN cooperatively enhances their antitumor activity in human hepatocellular carcinoma cells.

    PubMed

    Rakshit, Nargis; Yang, Sijun; Zhou, Wei; Xu, Yi; Deng, Chenghui; Yang, Jiecheng; Yu, Huijun; Wei, Wenxiang

    2016-08-01

    Both inhibitor of growth 4 (ING4) and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) are well known as tumor suppressors that are closely related to tumor occurrence and progression. It was reported that ING4 and PTEN showed synergistic antitumor activities in nasopharyngeal carcinoma cells. The two tumor suppressors demonstrated synergistic effect on growth inhibition and apoptosis activation. In this study, we investigated their therapeutic potential in hepatocellular carcinoma (HCC) cells. Recombinant adenoviruses co-expressing ING4 and PTEN (Ad-ING4-PTEN) were constructed, and the antitumor effect on SMMC-7721 and HepG2 HCC cells was evaluated. Ad-ING4-PTEN cooperatively inhibited cell growth, stimulated apoptosis, and suppressed invasion in both HCC cells, and regulated cell cycle in SMMC-7721. Further studies showed that the combination of ING4 and PTEN by Ad-ING4-PTEN cooperatively enhanced the alteration of the expression of cell cycle-related proteins (p53, p21, and cyclin D1) and apoptotic factors (Bad, Bcl-2, Bcl-XL, and Bax), which are involved in the regulation of cell cycle and the activation of apoptotic pathways, leading to the synergistic antitumor effect. These results indicate that the combination of ING4 and PTEN may provide an effective therapeutic strategy for HCC.

  9. Loss of Pten promotes angiogenesis and enhanced vegfaa expression in zebrafish.

    PubMed

    Choorapoikayil, Suma; Weijts, Bart; Kers, Rianne; de Bruin, Alain; den Hertog, Jeroen

    2013-09-01

    Angiogenesis, the emergence of vessels from an existing vascular network, is pathologically associated with tumor progression and is of great interest for therapeutic intervention. PTEN is a frequently mutated tumor suppressor and has been linked to the progression of many types of tumors, including hemangiosarcomas in zebrafish. Here, we report that mutant zebrafish embryos lacking functional Pten exhibit enhanced angiogenesis, accompanied by elevated levels of phosphorylated Akt (pAkt). Inhibition of phosphoinositide 3-kinase (PI3K) by LY294002 treatment and application of sunitinib, a widely used anti-angiogenic compound, suppressed enhanced angiogenesis in Pten mutants. Vegfaa has a crucial role in angiogenesis and vegfaa expression was upregulated in embryos lacking functional Pten. Interestingly, vegfaa expression was also upregulated in hemangiosarcomas from haploinsufficient adult zebrafish Pten mutants. Elevated vegfaa expression in mutant embryos lacking functional Pten was suppressed by LY294002. Surprisingly, sunitinib treatment dramatically enhanced vegfaa expression in Pten mutant embryos, which might account for tumor relapse in human patients who are treated with sunitinib. Combined treatment with suboptimal concentrations of sunitinib and LY294002 rescued enhanced angiogenesis in pten mutant embryos without the dramatic increase in vegfaa expression, suggesting a new approach for therapeutic intervention in VEGFR-signaling-dependent tumors.

  10. Prognostic impact and the relevance of PTEN copy number alterations in patients with advanced colorectal cancer (CRC) receiving bevacizumab.

    PubMed

    Price, Timothy J; Hardingham, Jennifer E; Lee, Chee K; Townsend, Amanda R; Wrin, Joseph W; Wilson, Kate; Weickhardt, Andrew; Simes, Robert J; Murone, Carmel; Tebbutt, Niall C

    2013-06-01

    Loss of phosphatase and tensin homologue (PTEN) expression may be prognostic in colorectal cancer (CRC) and may have a correlation with vascular endothelial growth factor (VEGF) expression via hypoxia-inducible factor 1 (HIF-1) alpha, and the PI3K/mTOR pathways. We therefore have explored the prognostic association of PTEN loss and the potential that PTEN loss may be predictive of outcome with bevacizumab. Patients enrolled in the AGITG MAX trial, a randomized Phase III trial of capecitabine (C) +/- bevacizumab (B) (+/- mitomycin C [M]) with available tissues were analyzed for PTEN expression (loss vs. no loss) as assessed using a Taqman® copy number assay (CNA). Of the original 471 patients enrolled, tissues from 302 (64.1%) patients were analyzed. PTEN loss was observed in 38.7% of patients. There was no relationship between PTEN loss and KRAS or BRAF mutation. PTEN status was not prognostic for progression-free survival (PFS) or overall survival (OS) in multivariate analyses adjusting for other baseline factors; loss versus no loss PFS hazard ratio (HR) 0.9 (0.7-1.16), OS HR 1.04 (0.79-1.38). PTEN was not prognostic when assessed by KRAS and BRAF status. By using the comparison of C versus CB+CBM, PTEN status was not significantly predictive of the effectiveness of B for PFS or OS. PTEN status was not prognostic for survival in advanced colorectal cancer, irrespective of KRAS or BRAF status. PTEN status did not significantly predict different benefit with bevacizumb therapy.

  11. Relationship between PTEN and VEGF expression and clinicopathological characteristics in HCC.

    PubMed

    Mi, Denghai; Yi, Jilin; Liu, Enyu; Li, Xingrui

    2006-01-01

    To investigate the expressions and significance of the tumor suppressor gene phosphatase and tensin homolog deleted on chromosome ten protein (PTEN) and vascular endothelial growth factor (VEGF) in hepatocellular carcinoma (HCC), and to analyze the relationship between their expressions and the tumor's invasion and their peri-carcinomatous tissues, the correlation of their expressions with the tumor's clinicopathological characteristics and invasion potential were studied. Our study showed that the expression level of PTEN in HCC was remarkably lower than that in peri-carcinomatous liver tissues, while the expressions of both VEGF and MVD were higher than that in peri-carcinomatous liver tissues. Correlation analysis revealed that the expression of PTEN was negatively related to the progression of the pathological differentiation and invasion of tumor, whereas the expressions of VEGF and MVD were positively related. Moreover, there was a negative relationship between the expression of PTEN and the expressions of VEGF and MVD, and a positive one between VEGF and MVD. The expressions of PTEN and VEGF may reveal the degree of differentiation and the invasive potential of HCC tissues. The mechanism by which the lack of PTEN expression probably induces abnormal hyperexpression of VEGF may play an important role in the invasion and metastasis of HCC.

  12. Expression status and mutational analysis of the PTEN and P13K subunit genes in ovarian granulosa cell tumors.

    PubMed

    Bittinger, Sophie; Alexiadis, Maria; Fuller, Peter J

    2009-04-01

    Granulosa cell tumors (GCT) are a unique subset of ovarian tumors which have a molecular phenotype resembling that of follicle stimulating hormone (FSH)-stimulated pre-ovulatory granulosa cells. FSH acts via its receptor to stimulate signaling pathways including the phosphatidylinositol 3-kinase (PI3K)-AKT pathway. Activation of this pathway occurs in solid tumors, including ovarian epithelial tumors, through mutation of the PI3K subunit genes or inactivation of the tumor suppressor, PTEN. Activation of this pathway would be predicted to be tumorigenic in granulosa cells.Expression of the 2 PI3K subunit genes, PIK3CA, which encodes the catalytic subunit, and PIK3R1, which encodes the regulatory subunit, together with the PTEN gene was determined in a panel of GCT, 2 human GCT-derived cell lines, COV434 and KGN, and normal ovary. Direct sequence analysis was used to screen for mutations. Expression of all 3genes was observed in the GCT without evidence of overexpression for the PI3K subunit genes or loss of expression for PTEN. Sequence analysis of amplicons spanning exons 9and 20, in which greater than 75% of mutations occur in the PIK3CA gene did not identify any missense mutations. Similarly, the previously reported deletions in exons 12 and 13 of the PIK3R1 were not found in the GCT. Three amplicons spanning the entire coding sequence of the PTEN gene were sequenced; neither deletions nor mutations were identified.These findings suggest that activation of PI3K signaling through PI3K/PTEN mutation or altered expression, in contrast to many other types of solid tumor, is not associated with GCT.

  13. Expression and significance of PTEN and VEGF in canine mammary gland tumours.

    PubMed

    Qiu, C W; Lin, D G; Wang, J Q; Li, C Y; Deng, G Z

    2008-08-01

    To investigate the relationship between the expression of the PTEN (phosphatase and tensin homolog deleted on chromosometen) and VEGF (vascular endothelial growth factor) and the clinicopathological features in canine mammary gland tumours, the expression levels of PTEN and VEGF protein were assessed in 50 cases of canine mammary gland tumours tissues and 4 cases of normal mammary gland tissues with using immunohistochemical method. The over-expression rate of PTEN protein was 100% in normal and well-differentiated mammary gland tissues and 67% in breast cancer cases respectively with a significant difference between the two groups (P<0.01). Expression of PTEN was not related to age and tumour size, but closely correlated to lymph node metastasis (P<0.01). The over-expression rate of VEGF protein was 33.3% in normal mammary gland tissues, and 78% in canine mammary gland tumours with a significant difference between the two groups (P<0.01). Expression of VEGF was not related to age or tumour size, but closely correlated with lymph node metastasis and clinical stage (P<0.05). Therefore the combination detection of PTEN and VEGF could serve as an important index to estimate the biological behavior and prognosis of canine mammary gland tumours. Reduced expression of PTEN might be involved in carcinogenesis and progression of canine breast cancer by up-regulating the VEGF expression to enhance angiogenesis.

  14. PTEN regulates angiogenesis and VEGF expression through phosphatase-dependent and -independent mechanisms in HepG2 cells.

    PubMed

    Tian, Tao; Nan, Ke-Jun; Wang, Shu-Hong; Liang, Xuan; Lu, Chuang-Xin; Guo, Hui; Wang, Wen-Juan; Ruan, Zhi-Ping

    2010-07-01

    Hepatocellular carcinoma (HCC) is a typical hypervascular tumor, and increased levels of vascular endothelial growth factor (VEGF) are associated with progression of HCC. Tumor suppression gene PTEN (phosphatase and tensin homolog deleted on chromosome 10), an important antagonist of the phosphoinositide-3-kinase (PI3K)/adenosine triphosphate-dependent tyrosine kinase (Akt) pathway, is also commonly lost or mutated in HCC. However, the effect of PTEN on VEGF-mediated angiogenesis in HCC remains unknown. To explore this relationship, we expressed a panel of PTEN mutants in human HCC cells with low expression of PTEN (HepG2 cells). Overexpression of PTEN in HepG2 cells resulted in the downregulation of proliferation and migration of cocultured endothelial cells and decreased expression of hypoxia-inducible factor 1 (HIF-1) and VEGF. Similarly, using a nude mouse model, we demonstrated that PTEN decreased expression of HIF-1 and VEGF and suppressed HepG2-induced angiogenesis. This inhibitory effect was not observed in cells expressing a phosphatase-deficient PTEN mutant, suggesting that PTEN inhibits angiogenesis and VEGF through a phosphatase-dependent pathway. Strikingly, reintroducing the C2 domain of PTEN also resulted in a significant decrease in angiogenesis and VEGF expression, although it did not affect Akt phosphorylation or HIF-1 expression. In summary, this study suggests the novel viewpoint that PTEN suppresses angiogenesis and VEGF expression in HCC through both phosphatase-dependent and -independent mechanisms.

  15. PTEN downregulates p75NTR expression by decreasing DNA-binding activity of Sp1

    SciTech Connect

    Rankin, Sherri L.; Guy, Clifford S.; Mearow, Karen M.

    2009-02-13

    p75NTR is expressed throughout the nervous system and its dysregulation is associated with pathological conditions. We have recently demonstrated a signalling cascade initiated by laminin (LN), which upregulates PTEN and downregulates p75NTR. Here we investigate the mechanism by which PTEN modulates p75NTR. Studies using PTEN mutants show that its protein phosphatase activity directly modulates p75NTR protein expression. Nuclear relocalization of PTEN subsequent to LN stimulation suggests transcriptional control of p75NTR expression, which was confirmed following EMSA and ChIP analysis of Sp1 transcription factor binding activity. LN and PTEN independently decrease the DNA-binding ability of PTEN to the p75NTR promoter. Sp1 regulation of p75NTR occurs via dephosphorylation of Sp1, thus reducing p75NTR transcription and protein expression. This mechanism represents a novel regulatory pathway which controls the expression level of a receptor with broad implications not only for the development of the nervous system but also for progression of pathological conditions.

  16. Deletion of PTEN produces autism-like behavioral deficits and alterations in synaptic proteins

    PubMed Central

    Lugo, Joaquin N.; Smith, Gregory D.; Arbuckle, Erin P.; White, Jessika; Holley, Andrew J.; Floruta, Crina M.; Ahmed, Nowrin; Gomez, Maribel C.; Okonkwo, Obi

    2014-01-01

    Many genes have been implicated in the underlying cause of autism but each gene accounts for only a small fraction of those diagnosed with autism. There is increasing evidence that activity-dependent changes in neuronal signaling could act as a convergent mechanism for many of the changes in synaptic proteins. One candidate signaling pathway that may have a critical role in autism is the PI3K/AKT/mTOR pathway. A major regulator of this pathway is the negative repressor phosphatase and tensin homolog (PTEN). In the current study we examined the behavioral and molecular consequences in mice with neuron subset-specific deletion of PTEN. The knockout (KO) mice showed deficits in social chamber and social partition test. KO mice demonstrated alterations in repetitive behavior, as measured in the marble burying test and hole-board test. They showed no changes in ultrasonic vocalizations emitted on postnatal day 10 or 12 compared to wildtype (WT) mice. They exhibited less anxiety in the elevated-plus maze test and were more active in the open field test compared to WT mice. In addition to the behavioral alterations, KO mice had elevation of phosphorylated AKT, phosphorylated S6, and an increase in S6K. KO mice had a decrease in mGluR but an increase in total and phosphorylated fragile X mental retardation protein. The disruptions in intracellular signaling may be why the KO mice had a decrease in the dendritic potassium channel Kv4.2 and a decrease in the synaptic scaffolding proteins PSD-95 and SAP102. These findings demonstrate that deletion of PTEN results in long-term alterations in social behavior, repetitive behavior, activity, and anxiety. In addition, deletion of PTEN significantly alters mGluR signaling and many synaptic proteins in the hippocampus. Our data demonstrates that deletion of PTEN can result in many of the behavioral features of autism and may provide insights into the regulation of intracellular signaling on synaptic proteins. PMID:24795561

  17. Deletion of PTEN produces autism-like behavioral deficits and alterations in synaptic proteins.

    PubMed

    Lugo, Joaquin N; Smith, Gregory D; Arbuckle, Erin P; White, Jessika; Holley, Andrew J; Floruta, Crina M; Ahmed, Nowrin; Gomez, Maribel C; Okonkwo, Obi

    2014-01-01

    Many genes have been implicated in the underlying cause of autism but each gene accounts for only a small fraction of those diagnosed with autism. There is increasing evidence that activity-dependent changes in neuronal signaling could act as a convergent mechanism for many of the changes in synaptic proteins. One candidate signaling pathway that may have a critical role in autism is the PI3K/AKT/mTOR pathway. A major regulator of this pathway is the negative repressor phosphatase and tensin homolog (PTEN). In the current study we examined the behavioral and molecular consequences in mice with neuron subset-specific deletion of PTEN. The knockout (KO) mice showed deficits in social chamber and social partition test. KO mice demonstrated alterations in repetitive behavior, as measured in the marble burying test and hole-board test. They showed no changes in ultrasonic vocalizations emitted on postnatal day 10 or 12 compared to wildtype (WT) mice. They exhibited less anxiety in the elevated-plus maze test and were more active in the open field test compared to WT mice. In addition to the behavioral alterations, KO mice had elevation of phosphorylated AKT, phosphorylated S6, and an increase in S6K. KO mice had a decrease in mGluR but an increase in total and phosphorylated fragile X mental retardation protein. The disruptions in intracellular signaling may be why the KO mice had a decrease in the dendritic potassium channel Kv4.2 and a decrease in the synaptic scaffolding proteins PSD-95 and SAP102. These findings demonstrate that deletion of PTEN results in long-term alterations in social behavior, repetitive behavior, activity, and anxiety. In addition, deletion of PTEN significantly alters mGluR signaling and many synaptic proteins in the hippocampus. Our data demonstrates that deletion of PTEN can result in many of the behavioral features of autism and may provide insights into the regulation of intracellular signaling on synaptic proteins.

  18. Loss of tumour suppressor PTEN expression in renal injury initiates SMAD3- and p53-dependent fibrotic responses.

    PubMed

    Samarakoon, Rohan; Helo, Sevann; Dobberfuhl, Amy D; Khakoo, Nidah S; Falke, Lucas; Overstreet, Jessica M; Goldschmeding, Roel; Higgins, Paul J

    2015-08-01

    Deregulation of the tumour suppressor PTEN occurs in lung and skin fibrosis and diabetic and ischaemic renal injury. However, the potential role of PTEN and associated mechanisms in the progression of kidney fibrosis is unknown. Tubular and interstitial PTEN expression was dramatically decreased in several models of renal injury, including aristolochic acid nephropathy (AAN), streptozotocin (STZ)-mediated injury and ureteral unilateral obstruction (UUO), correlating with Akt, p53 and SMAD3 activation and fibrosis. Stable silencing of PTEN in HK-2 human tubular epithelial cells induced dedifferentiation and CTGF, PAI-1, vimentin, α-SMA and fibronectin expression, compared to HK-2 cells expressing control shRNA. Furthermore, PTEN knockdown stimulated Akt, SMAD3 and p53(Ser15) phosphorylation, with an accompanying decrease in population density and an increase in epithelial G1 cell cycle arrest. SMAD3 or p53 gene silencing or pharmacological blockade partially suppressed fibrotic gene expression and relieved growth inhibition orchestrated by deficiency or inhibition of PTEN. Similarly, shRNA suppression of PAI-1 rescued the PTEN loss-associated epithelial proliferative arrest. Moreover, TGFβ1-initiated fibrotic gene expression is further enhanced by PTEN depletion. Combined TGFβ1 treatment and PTEN silencing potentiated epithelial cell death via p53-dependent pathways. Thus, PTEN loss initiates tubular dysfunction via SMAD3- and p53-mediated fibrotic gene induction, with accompanying PAI-1-dependent proliferative arrest, and cooperates with TGFβ1 to induce the expression of profibrotic genes and tubular apoptosis.

  19. Effect of TIMP1 transfection on PTEN expression in human kidney proximal tubular cells.

    PubMed

    Chen, J X; Cai, G Y; Chen, X M; Liu, H; Chen, X; Peng, Y M; Liu, F Y; Li, Z; Shi, S Z

    2015-12-21

    To explore the role of metalloproteinase-1 (TIMP-1) tissue inhibitor in the mechanisms of kidney aging, we observed the effects of sense and antisense transfection of TIMP-1 and of metalloproteinase (MMP) inhibitors on phosphatase and tensin homolog (PTEN), vascular endothelial growth factor (VEGF), and Flk-1 expression in TIMP-1 transgenic human proximal tubular epithelial cells (HKCs). Transfected HKCs were co-incubated with 100 μM MMP-2 and MMP-9 inhibitor III for 24 h to affect enzyme inhibition. TIMP-1, MMP-2, MMP-9, PTEN, VEGF, and Flk-1 mRNA expression was detected by reverse transcription-polymerase chain reaction. PTEN, VEGF, and Flk-1 protein expression in cells of each experimental group was measured by indirect immunofluorescence. We found that PTEN expression was up-regulated (P < 0.05) in the sense TIMP-1-transfected group (P < 0.05) compared with the non-transfected and empty vector groups, and that expression of VEGF and Flk-1 was down-regulated (P < 0.05). In contrast, the antisense TIMP-1 transgenic group showed the opposite results (P < 0.05). No significant differences in expression of PTEN, VEGF, or Flk-1 were observed among the MMP- 2/MMP-9 inhibitor III, non-transfected, and empty vector groups (P > 0.05). These results suggest that in the progression of renal aging, high expression of TIMP-1 up-regulates PTEN expression through an MMP-independent pathway, and subsequently down-regulates the expression of VEGF and Flk-1, indicating that PTEN and TIMP-1 are involved in the aging-associated impairment of renal angiogenesis. Our study provides a theoretical basis for further exploration of the mechanism underlying TIMP- 1 participation in renal aging progression.

  20. Differences in Circulating microRNAs between Grazing and Grain-Fed Wagyu Cattle Are Associated with Altered Expression of Intramuscular microRNA, the Potential Target PTEN, and Lipogenic Genes.

    PubMed

    Muroya, Susumu; Shibata, Masahiro; Hayashi, Masayuki; Oe, Mika; Ojima, Koichi

    2016-01-01

    We aimed to understand the roles of miRNAs in the muscle tissue maturation and those of circulating microRNAs (c-miRNAs) in beef production of Japanese Black (JB) cattle (Wagyu), a breed with genetically background of superior intermuscular fat depot, by comparing different feeding conditions (indoor grain-feeding vs. grazing on pasture). The cattle at 18 months old were assigned to pasture feeding or conventional indoor grain feeding conditions for 5 months. Microarray analysis of c-miRNAs from the plasma extracellular vesicles led to the detection of a total of 202 bovine miRNAs in the plasma, including 15 miRNAs that differed between the feeding conditions. Validation of the microarray results by qPCR showed that the circulating miR-10b level in the grazing cattle was upregulated compared to that of the grain-fed cattle. In contrast, the levels of miR-17-5p, miR-19b, miR-29b, miR-30b-5p, miR-98, miR-142-5p, miR-301a, miR-374b, miR-425-5p, and miR-652 were lower in the grazing cattle than in the grain-fed cattle. Bioinformatic analysis indicated that the predicted target genes of those c-miRNAs were enriched in gene ontology terms associated with blood vessel morphogenesis, plasma membrane, focal adhesion, endocytosis, collagen, ECM-receptor interaction, and phosphorylation. In the grazing cattle, the elevation of miR-10b expression in the plasma was coincident with its elevation in the longissimus lumborum (LL) muscle. Expression of bovine-specific miR-2478, the most plasma-enriched miRNA, tended to be also upregulated in the muscle but not in the plasma. Furthermore, grazing caused the downregulated mRNA expression of predicted miR-10b and/or miR-2478 target genes, such as DNAJB2, PTEN, and SCD1. Thus, the feeding system used for JB cattle affected the c-miRNAs that could be indicators of grain feeding. Among these, miR-10b expression was especially associated with feeding-induced changes and with the expression of the potential target genes responsible for

  1. Differences in Circulating microRNAs between Grazing and Grain-Fed Wagyu Cattle Are Associated with Altered Expression of Intramuscular microRNA, the Potential Target PTEN, and Lipogenic Genes.

    PubMed

    Muroya, Susumu; Shibata, Masahiro; Hayashi, Masayuki; Oe, Mika; Ojima, Koichi

    2016-01-01

    We aimed to understand the roles of miRNAs in the muscle tissue maturation and those of circulating microRNAs (c-miRNAs) in beef production of Japanese Black (JB) cattle (Wagyu), a breed with genetically background of superior intermuscular fat depot, by comparing different feeding conditions (indoor grain-feeding vs. grazing on pasture). The cattle at 18 months old were assigned to pasture feeding or conventional indoor grain feeding conditions for 5 months. Microarray analysis of c-miRNAs from the plasma extracellular vesicles led to the detection of a total of 202 bovine miRNAs in the plasma, including 15 miRNAs that differed between the feeding conditions. Validation of the microarray results by qPCR showed that the circulating miR-10b level in the grazing cattle was upregulated compared to that of the grain-fed cattle. In contrast, the levels of miR-17-5p, miR-19b, miR-29b, miR-30b-5p, miR-98, miR-142-5p, miR-301a, miR-374b, miR-425-5p, and miR-652 were lower in the grazing cattle than in the grain-fed cattle. Bioinformatic analysis indicated that the predicted target genes of those c-miRNAs were enriched in gene ontology terms associated with blood vessel morphogenesis, plasma membrane, focal adhesion, endocytosis, collagen, ECM-receptor interaction, and phosphorylation. In the grazing cattle, the elevation of miR-10b expression in the plasma was coincident with its elevation in the longissimus lumborum (LL) muscle. Expression of bovine-specific miR-2478, the most plasma-enriched miRNA, tended to be also upregulated in the muscle but not in the plasma. Furthermore, grazing caused the downregulated mRNA expression of predicted miR-10b and/or miR-2478 target genes, such as DNAJB2, PTEN, and SCD1. Thus, the feeding system used for JB cattle affected the c-miRNAs that could be indicators of grain feeding. Among these, miR-10b expression was especially associated with feeding-induced changes and with the expression of the potential target genes responsible for

  2. Differences in Circulating microRNAs between Grazing and Grain-Fed Wagyu Cattle Are Associated with Altered Expression of Intramuscular microRNA, the Potential Target PTEN, and Lipogenic Genes

    PubMed Central

    Shibata, Masahiro; Hayashi, Masayuki; Oe, Mika; Ojima, Koichi

    2016-01-01

    We aimed to understand the roles of miRNAs in the muscle tissue maturation and those of circulating microRNAs (c-miRNAs) in beef production of Japanese Black (JB) cattle (Wagyu), a breed with genetically background of superior intermuscular fat depot, by comparing different feeding conditions (indoor grain-feeding vs. grazing on pasture). The cattle at 18 months old were assigned to pasture feeding or conventional indoor grain feeding conditions for 5 months. Microarray analysis of c-miRNAs from the plasma extracellular vesicles led to the detection of a total of 202 bovine miRNAs in the plasma, including 15 miRNAs that differed between the feeding conditions. Validation of the microarray results by qPCR showed that the circulating miR-10b level in the grazing cattle was upregulated compared to that of the grain-fed cattle. In contrast, the levels of miR-17-5p, miR-19b, miR-29b, miR-30b-5p, miR-98, miR-142-5p, miR-301a, miR-374b, miR-425-5p, and miR-652 were lower in the grazing cattle than in the grain-fed cattle. Bioinformatic analysis indicated that the predicted target genes of those c-miRNAs were enriched in gene ontology terms associated with blood vessel morphogenesis, plasma membrane, focal adhesion, endocytosis, collagen, ECM-receptor interaction, and phosphorylation. In the grazing cattle, the elevation of miR-10b expression in the plasma was coincident with its elevation in the longissimus lumborum (LL) muscle. Expression of bovine-specific miR-2478, the most plasma-enriched miRNA, tended to be also upregulated in the muscle but not in the plasma. Furthermore, grazing caused the downregulated mRNA expression of predicted miR-10b and/or miR-2478 target genes, such as DNAJB2, PTEN, and SCD1. Thus, the feeding system used for JB cattle affected the c-miRNAs that could be indicators of grain feeding. Among these, miR-10b expression was especially associated with feeding-induced changes and with the expression of the potential target genes responsible for

  3. Molecular genetic alterations in endometrioid carcinomas of the ovary: similar frequency of beta-catenin abnormalities but lower rate of microsatellite instability and PTEN alterations than in uterine endometrioid carcinomas.

    PubMed

    Catasús, Lluis; Bussaglia, Elena; Rodrguez, Ingrid; Gallardo, Alberto; Pons, Cristina; Irving, Julie A; Prat, Jaime

    2004-11-01

    Endometrioid carcinomas of the ovary closely resemble their uterine counterparts. It has been suggested that the former tumors have the same molecular alterations (microsatellite instability [MSI], PTEN, and beta-catenin) described in endometrioid carcinomas of the uterus. We analyzed 55 ovarian carcinomas, including 22 endometrioid, 18 clear cell, and 15 mixed types. MSI was detected in 5 of 39 cases (13%). MLH1 promoter hypermethylation was identified in 2 of the 5 MSI-positive tumors. PTEN was mutated in 5 of 54 cases (9%); of these, 3 had MSI and exhibited frameshift mutations in short-coding mononucleotide repeats. Beta-catenin nuclear expression was detected in 11 of 54 cases (20%) by immunostaining; of these, 7 exhibited CTNNB1 gene mutations. These alterations were found more frequently in endometrioid carcinomas than in tumors of the other 2 groups. Among the former tumors, MSI was detected in 3 of 17 cases (17.5%); PTEN mutations, in 3 of 21 (14%); and beta-catenin, in 8 of 21 (38%). The molecular alterations were found more often in tumors associated with endometriosis than in tumors without endometriosis. Six endometrioid tumors demonstrating matrix metalloproteinase-7 (MMP-7) immunoreactivity with nuclear accumulation of beta-catenin had good outcomes, in contrast to poor outcomes in 7 of 9 predominantly nonendometrioid tumors demonstrating expression of MMP-7 only. We found a similar frequency of beta-catenin abnormalities but lower rates of MSI and PTEN alterations than in uterine endometrioid carcinomas. Alterations in beta-catenin and PTEN genes, as well as MSI, are frequent in low-stage ovarian carcinomas of endometrioid type that have a favorable prognosis.

  4. PTEN expression in ovine granulosa cells increases during terminal follicular growth.

    PubMed

    Froment, Pascal; Bontoux, Martine; Pisselet, Claudine; Monget, Philippe; Dupont, Joëlle

    2005-04-25

    In the present paper, we have studied the expression of the Phosphatase and TENsin homolog deleted on chromosome 10 (PTEN) and its putative biological role in the sheep ovary. We found by Northern-blot, immunohistochemistry and immunoblot that PTEN is highly expressed in granulosa cells from large differentiated follicles (LF) in comparison with small proliferating follicles (SF) (P < 0.001), with no clear effect of follicle quality. Moreover, the PTEN lipid phosphatase activity is also higher in LF than in SF (P < 0.01). In contrast, levels of the phosphorylated form of AKT (pAKT) are lower in LF than in SF (P < 0.0001). IGF-I and insulin but not FSH, LH or forskolin are able to stimulate the expression of PTEN mRNA (P < 0.001) and protein by ovine granulosa cells after 48 h of culture in vitro. An IGF-1 time course analysis showed that expression of PTEN protein appeared after 12h of culture, concomitant with the fall of the pAKT levels, which peaked after 6h of stimulation with IGF-I. Moreover, transfection experiments showed that overexpression of PTEN in ovine granulosa cells induced a decrease and an increase in E2F and p27 promoter activity, respectively (P < 0.05). Overall, our present data show for the first time that the expression of PTEN increases during terminal follicular growth. This increase, that might be induced by IGF-I but not FSH, would participate in the proliferation/differentiation transition of ovine granulosa cells in differentiating follicles.

  5. Joint loss of PAX2 and PTEN expression in endometrial precancers and cancer

    PubMed Central

    Monte, Nicolas M.; Webster, Kaitlyn A.; Neuberg, Donna; Dressler, Gregory R.; Mutter, George L.

    2010-01-01

    Latent endometrial carcinoma precancers are normal appearing endometrial glands with sporadic loss of tumor suppressor gene function such as PTEN. Progression to carcinoma is inefficient and requires additional genetic damage that creates a histologic precursor lesion called endometrial intraepithelial neoplasia (EIN). In this study, we examined loss of PAX2 expression, a gene required for embryonic uterine development, during endometrial carcinogenesis. Normal proliferative, EIN, and malignant (endometrial adenocarcinoma) endometrial tissues were immunostained for PTEN and PAX2. Proliferative samples with loss of protein in at least one gland were scored as latent precancers. EIN and cancer lesions were scored by the majority pattern. Overall prevalence and topography of joint PAX2-PTEN expression loss was examined. The prevalence of PAX2 protein loss in the sequence of normal to precancer to cancer was 36%, 71%, and 77% respectively, and for PTEN 49%, 44%, and 68%. Normal endometrial prevalence of PAX2 or PTEN deficient latent precancers was unaffected by biopsy indication, but increased significantly with age. Coincident loss of PAX2 and PTEN expression in an individual normal endometrium was seen in 21% of patients, but usually involved different glands. Coincident loss was more common in precancers (31%) and carcinoma (55%), in which case both markers were protein null in an overlapping clonal distribution. PAX2 and PTEN protein loss occur independently and accumulate with increasing age in latent precancers of normal premenopausal endometrium. Loss of function of both genes in an overlapping distribution characterizes clinical emergence of a premalignant lesion which is carried forward to carcinoma. PMID:20631067

  6. PTEN-induction in U251 glioma cells decreases the expression of insulin-like growth factor binding protein-2

    SciTech Connect

    Levitt, Randy J.; Georgescu, Maria-Magdalena; Pollak, Michael . E-mail: michael.pollak@mcgill.ca

    2005-11-04

    PTEN is a tumor suppressor gene whose loss of function is observed in {approx}40-50% of human cancers. Although insulin-like growth factor binding protein-2 (IGFBP-2) was classically described as a growth inhibitor, multiple recent reports have shown an association of overexpression and/or high serum levels of IGFBP-2 with poor prognosis of several malignancies, including gliomas. Using an inducible PTEN expression system in the PTEN-null glioma cell line U251, we demonstrate that PTEN-induction is associated with reduced proliferation, increased apoptosis, and a substantial reduction of the high levels of IGFBP-2 expression. The PTEN-induced decrease in IGFBP-2 expression could be mimicked with the PI3-kinase inhibitor LY294002, indicating that the lipid phosphatase activity of PTEN is responsible for the observed effect. However, the rapamycin analog CCI-779 did not affect IGFBP-2 expression, suggesting that the PTEN-induced decrease in IGFBP-2 expression is not attributable to decreased mTOR signalling. Recombinant human IGFBP-2 was unable to rescue U251-PTEN cells from the antiproliferative effects of PTEN, and IGFBP-2 siRNA did not affect the IGF-dependent or -independent growth of this cell line. These results suggest that the clinical data linking IGFBP-2 expression to poor prognosis may arise, at least in part, because high levels of IGFBP-2 expression correlate with loss of function of PTEN, which is well known to lead to aggressive behavior of gliomas. Our results motivate translational research regarding the relationship between IGFBP-2 expression and loss of function of PTEN.

  7. miR-17 inhibitor suppressed osteosarcoma tumor growth and metastasis via increasing PTEN expression

    SciTech Connect

    Gao, Yong; Luo, Ling-hui; Li, Shuai; Yang, Cao

    2014-02-07

    Highlights: • miR-17 was increased in OS tissues and cell lines. • Inhibition of miR-17 suppressed OS cell proliferation. • Inhibition of miR-17 suppressed OS cell migration and invasion. • PTEN was a target of miR-17. • miR-17 was negatively correlated with PTEN in OS tissues. - Abstract: MicroRNAs (miRNAs) play essential roles in cancer development and progression. Here, we investigated the role of miR-17 in the progression and metastasis of osteosarcoma (OS). miR-17 was frequently increased in OS tissues and cell lines. Inhibition of miR-17 in OS cell lines substantially suppressed cell proliferation, migration, and invasion. Phosphatase and tensin homolog (PTEN) was identified as a target of miR-17, and ectopic expression of miR-17 inhibited PTEN by direct binding to its 3′-untranslated region (3′-UTR). Expression of miR-17 was negatively correlated with PTEN in OS tissues. Together, these findings indicate that miR-17 acts as an oncogenic miRNA and may contribute to the progression and metastasis of OS, suggesting miR-17 as a potential novel diagnostic and therapeutic target of OS.

  8. ZN2+ INDUCES COX-2 EXPRESSION THROUGH DOWNREGULATION OF LIPID PHOSPHATASE PTEN

    EPA Science Inventory

    Zn2+ Induces COX-2 Expression through Downregulation of Lipid Phosphatase PTEN
    Weidong Wu*, James M. Samet, Philip A. Bromberg*?, Young E. Whang?, and Lee M. Graves* ?
    *CEMALB, ?Department of Medicine, and ?Department of Pharmacology, UNC-Chapel Hill, NC27599; Human Studie...

  9. The effect of androgens on ovarian follicle maturation: Dihydrotestosterone suppress FSH-stimulated granulosa cell proliferation by upregulating PPARγ-dependent PTEN expression.

    PubMed

    Chen, Mei-Jou; Chou, Chia-Hung; Chen, Shee-Uan; Yang, Wei-Shiung; Yang, Yu-Shih; Ho, Hong-Nerng

    2015-12-17

    Intraovarian hyperandrogenism is one of the determining factors of follicular arrest in women with polycystic ovary syndrome (PCOS). Using androgenized rat models, we investigated the effects of androgens on metabolism, as well as on factors involved in follicular arrest and the reduced number of estrus cycles. The dihydrotestosterone (DHT)-treated rats had fewer estrus cycles, higher numbers of large arrested follicles and an increased in body weight gain compared with the dehydroepiandrostenedione (DHEA)- and placebo-treated rats. In cultured rat granulosa cells, DHT suppressed follicle stimulating hormone (FSH)-induced granulosa cell proliferation and increased the accumulation of cells in the G2/M phase. DHT decreased phosphorylated Akt (p-Akt) and cyclin D1 levels through increasing PTEN. DHT-promoted PTEN expression was regulated by peroxisome proliferator-activated receptor gamma (PPARγ) in granulosa cells. Meanwhile, in the large follicles of the DHT-treated rats, the expressions of PPARγ and PTEN were higher, but the expression of p-Akt and proliferating cell nuclear antigen (PCNA) were lower. Conclusively, DHT and DHEA produced differential effects on metabolism in prepubertal female rats like clinical manifestations of women with PCOS. DHT treatment may affect ovarian follicular maturation by altering granulosa cell proliferation through the regulation of enhancing PPARγ dependent PTEN/p-Akt expression in the granulosa cells.

  10. The effect of androgens on ovarian follicle maturation: Dihydrotestosterone suppress FSH-stimulated granulosa cell proliferation by upregulating PPARγ-dependent PTEN expression.

    PubMed Central

    Chen, Mei-Jou; Chou, Chia-Hung; Chen, Shee-Uan; Yang, Wei-Shiung; Yang, Yu-Shih; Ho, Hong-Nerng

    2015-01-01

    Intraovarian hyperandrogenism is one of the determining factors of follicular arrest in women with polycystic ovary syndrome (PCOS). Using androgenized rat models, we investigated the effects of androgens on metabolism, as well as on factors involved in follicular arrest and the reduced number of estrus cycles. The dihydrotestosterone (DHT)-treated rats had fewer estrus cycles, higher numbers of large arrested follicles and an increased in body weight gain compared with the dehydroepiandrostenedione (DHEA)- and placebo-treated rats. In cultured rat granulosa cells, DHT suppressed follicle stimulating hormone (FSH)-induced granulosa cell proliferation and increased the accumulation of cells in the G2/M phase. DHT decreased phosphorylated Akt (p-Akt) and cyclin D1 levels through increasing PTEN. DHT-promoted PTEN expression was regulated by peroxisome proliferator-activated receptor gamma (PPARγ) in granulosa cells. Meanwhile, in the large follicles of the DHT-treated rats, the expressions of PPARγ and PTEN were higher, but the expression of p-Akt and proliferating cell nuclear antigen (PCNA) were lower. Conclusively, DHT and DHEA produced differential effects on metabolism in prepubertal female rats like clinical manifestations of women with PCOS. DHT treatment may affect ovarian follicular maturation by altering granulosa cell proliferation through the regulation of enhancing PPARγ dependent PTEN/p-Akt expression in the granulosa cells. PMID:26674985

  11. Inhibition of PTEN expression and activity by angiotensin II induces proliferation and migration of vascular smooth muscle cells.

    PubMed

    Dong, Xue; Yu, Lu-Gang; Sun, Rong; Cheng, Yan-Na; Cao, Hua; Yang, Kang-Min; Dong, Yi-Ning; Wu, Yan; Guo, Xiu-Li

    2013-01-01

    PTEN (phosphatase and tensin homolog deleted on chromosome 10) is a tumor suppressor and has been suggested recently to be involved in the regulation of cardiovascular diseases. The molecular mechanisms of this regulation are however poorly understood. This study shows that down regulation of PTEN expression and activity by angiotensin II (Ang II) increased proliferation and migration of vascular smooth muscle cells (VSMCs). The presence of Ang II induced rapid PTEN phosphorylation and oxidation in accordance with increased AKT and FAK phosphorylation. The Ang II-mediated VSMC proliferation and migration was inhibited when cellular PTEN expression was increased by AT1 inhibitor losartan, PPARγ agonist rosiglitazone, NF-κB inhibitor BAY 11-7082. Over expression of PTEN in VSMCs by adenovirus transduction also resulted in inhibition of cell proliferation and migration in response to Ang II. These results suggest that PTEN down-regulation is involved in proliferation and migration of VSMCs induced by Ang II. This provides insight into the molecular regulation of PTEN in vascular smooth muscle cells and suggests that targeting the action of PTEN may represent an effective therapeutic approach for the treatment of cardiovascular diseases.

  12. The expression profile for the tumour suppressor gene PTEN and associated polymorphic markers

    PubMed Central

    Hamilton, J A; Stewart, L M D; Ajayi, L; Gray, I C; Gray, N E; Roberts, K G; Watson, G J; Kaisary, A V; Snary, D

    2000-01-01

    PTEN, a putative tumour suppressor gene associated with prostate and other cancers, is known to be located within the chromosomal region 10q23.3. Transcription of the PTEN gives rise to multiple mRNA species. Analyses by Northern blots, using cell lines which express PTEN together with cell lines which have lost the PTEN or carry a truncated version of the gene, has allowed us to demonstrate that the pseudogene is not transcribed. In addition, 3′ RACE studies confirmed that the multiple mRNA species arising from the gene probably result from the use of alternative polyadenylation sites. No evidence for tissue- or cell-specific patterns of transcription was found. Analysis by 5′ RACE placed the putative site for the start of transcription around 830 bp upstream of the start codon. A map of the location of the PTEN gene with a series of overlapping YAC, BAC and PACs has been constructed and the relative position of eight microsatellite markers sited. Two known and one novel marker have been positioned within the gene, the others are in flanking regions. The more accurate location of these markers should help in future studies of the extent of gene loss. Several polymorphisms were also identified, all were within introns. Four of the common polymorphisms appear to be linked. In blood, DNA from 200 individuals, including normal, BPH and prostate cancer patients, confirmed this link. Only two samples of 200 did not carry the linked haplotype, both were patients with advanced prostate cancer. It is possible that such rearrangements within PTEN could be evidence of predisposition to prostate cancer in this small number of cases. © 2000 Cancer Research Campaign PMID:10817502

  13. Inhibition of AMPK and Krebs cycle gene expression drives metabolic remodeling of Pten-deficient preneoplastic thyroid cells.

    PubMed

    Antico Arciuch, Valeria G; Russo, Marika A; Kang, Kristy S; Di Cristofano, Antonio

    2013-09-01

    Rapidly proliferating and neoplastically transformed cells generate the energy required to support rapid cell division by increasing glycolysis and decreasing flux through the oxidative phosphorylation (OXPHOS) pathway, usually without alterations in mitochondrial function. In contrast, little is known of the metabolic alterations, if any, which occur in cells harboring mutations that prime their neoplastic transformation. To address this question, we used a Pten-deficient mouse model to examine thyroid cells where a mild hyperplasia progresses slowly to follicular thyroid carcinoma. Using this model, we report that constitutive phosphoinositide 3-kinase (PI3K) activation caused by PTEN deficiency in nontransformed thyrocytes results in a global downregulation of Krebs cycle and OXPHOS gene expression, defective mitochondria, reduced respiration, and an enhancement in compensatory glycolysis. We found that this process does not involve any of the pathways classically associated with the Warburg effect. Moreover, this process was independent of proliferation but contributed directly to thyroid hyperplasia. Our findings define a novel metabolic switch to glycolysis driven by PI3K-dependent AMPK inactivation with a consequent repression in the expression of key metabolic transcription regulators.

  14. Oncogenic signaling in Amphiregulin and EGFR-expressing PTEN-null human breast cancer

    PubMed Central

    Kappler, Christiana S.; Guest, Stephen T.; Irish, Jonathan C.; Garrett-Mayer, Elizabeth; Kratche, Zachary; Wilson, Robert C.; Ethier, Stephen P.

    2014-01-01

    A subset of triple negative breast cancer (TNBC) is characterized by overexpression of the epidermal growth factor receptor (EGFR) and loss of PTEN, and patients with these determinants have a poor prognosis. We used cell line models of EGFR-positive/PTEN null TNBC to elucidate the signaling networks that drive the malignant features of these cells and cause resistance to EGFR inhibitors. In these cells, amphiregulin (AREG)-mediated activation of EGFR results in up-regulation of fibronectin (FN1), which is known to be a mediator of invasive capacity via interaction with integrin β1. EGFR activity in this PTEN null background also results in Wnt/beta-catenin signaling and activation of NF-κB. In addition, AKT is constitutively phosphorylated in these cells and is resistant to gefitinib. Expression profiling demonstrated that AREG-activated EGFR regulates gene expression differently than EGF-activated EGFR, and functional analysis via genome-scale shRNA screening identified a set of genes, including PLK1 and BIRC5, that are essential for survival of SUM-149 cells, but are uncoupled from EGFR signaling. Thus, our results demonstrate that in cells with constitutive EGFR activation and PTEN loss, critical survival genes are uncoupled from regulation by EGFR, which likely mediates resistance to EGFR inhibitors. PMID:25454348

  15. miR-1297 mediates PTEN expression and contributes to cell progression in LSCC

    SciTech Connect

    Li, Xin; Wang, Hong-liang; Peng, Xin; Zhou, Hui-fang; Wang, Xin

    2012-10-19

    Highlights: Black-Right-Pointing-Pointer miR-1297 was found to be overexpressed in LSCC and contribute to the cell progression. Black-Right-Pointing-Pointer PTEN was confirmed to be a target gene of miR-1297. Black-Right-Pointing-Pointer Downregulation of PTEN can rescue the proliferation and invasion ability of miR-1297 downregulated Hep-2 cells. Black-Right-Pointing-Pointer Downregulation of miR-1297 inhibits tumor growth in vivo. -- Abstract: MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression after transcription, and are involved in cancer development. Laryngeal squamous cell carcinoma (LSCC) is one of the most common malignant neoplasms with increasing incidence in recent years. In this paper, we report the overexpression of miR-1297 in LSCC and Hep-2 cells. In addition, PTEN was identified to be directly regulated by miR-1297 through western blot and luciferase activity assay. Furthermore, downregulation of miR-1297 in Hep-2 cells was shown to inhibit cancer cell proliferation, migration, and tumor genesis. Our results document a new epigenetic mechanism for PTEN regulation in LSCC, which is crucial for the development of these tumors.

  16. MCT-1 expression and PTEN deficiency synergistically promote neoplastic multinucleation through the Src/p190B signaling activation.

    PubMed

    Wu, M-H; Chen, Y-A; Chen, H-H; Chang, K-W; Chang, I-S; Wang, L-H; Hsu, H-L

    2014-10-23

    Multinucleation is associated with malignant neoplasms; however, the molecular mechanism underlying the nuclear abnormality remains unclear. Loss or mutation of PTEN promotes the development of malignant tumors. We now demonstrate that increased expression of the oncogene MCT-1 (multiple copies in T-cell malignancy 1) antagonizes PTEN gene presentation, PTEN protein stability and PTEN functional activity, thereby further promoting phosphoinositide 3 kinase/AKT signaling, survival rate and malignancies of the PTEN-deficient cells. In the PTEN-null cancer cells, MCT-1 interacts with p190B and Src in vivo, supporting that they are in proximity of the signaling complexes. MCT-1 overexpression and PTEN loss synergistically augments the Src/p190B signaling function that leads to inhibition of RhoA activity. Under such a condition, the incidence of mitotic catastrophes including spindle multipolarity and cytokinesis failure is enhanced, driving an Src/p190B/RhoA-dependent neoplastic multinucleation. Targeting MCT-1 by the short hairpin RNA markedly represses the Src/p190B function, improves nuclear structures and suppresses xenograft tumorigenicity of the PTEN-null breast cancer cells. Consistent with the oncogenic effects in vitro, clinical evidence has confirmed that MCT-1 gene stimulation is correlated with p190B gene promotion and PTEN gene suppression in human breast cancer. Accordingly, MCT-1 gene induction is recognized as a potential biomarker of breast tumor development. Abrogating MCT-1 function may be a promising stratagem for management of breast cancer involving Src hyperactivation and/or PTEN dysfunction. PMID:24858043

  17. Early Behavioral Abnormalities and Perinatal Alterations of PTEN/AKT Pathway in Valproic Acid Autism Model Mice.

    PubMed

    Yang, Eun-Jeong; Ahn, Sangzin; Lee, Kihwan; Mahmood, Usman; Kim, Hye-Sun

    2016-01-01

    Exposure to valproic acid (VPA) during pregnancy has been linked with increased incidence of autism, and has repeatedly been demonstrated as a useful autism mouse model. We examined the early behavioral and anatomical changes as well as molecular changes in mice prenatally exposed to VPA (VPA mice). In this study, we first showed that VPA mice showed developmental delays as assessed with self-righting, eye opening tests and impaired social recognition. In addition, we provide the first evidence that primary cultured neurons from VPA-treated embryos present an increase in dendritic spines, compared with those from control mice. Mutations in phosphatase and tensin homolog (PTEN) gene are also known to be associated with autism, and mice with PTEN knockout show autistic characteristics. Protein expression of PTEN was decreased and the ratio of p-AKT/AKT was increased in the cerebral cortex and the hippocampus, and a distinctive anatomical change in the CA1 region of the hippocampus was observed. Taken together, our study suggests that prenatal exposure to VPA induces developmental delays and neuroanatomical changes via the reduction of PTEN level and these changes were detectable in the early days of life.

  18. Early Behavioral Abnormalities and Perinatal Alterations of PTEN/AKT Pathway in Valproic Acid Autism Model Mice

    PubMed Central

    Yang, Eun-Jeong; Ahn, Sangzin; Lee, Kihwan; Mahmood, Usman; Kim, Hye-Sun

    2016-01-01

    Exposure to valproic acid (VPA) during pregnancy has been linked with increased incidence of autism, and has repeatedly been demonstrated as a useful autism mouse model. We examined the early behavioral and anatomical changes as well as molecular changes in mice prenatally exposed to VPA (VPA mice). In this study, we first showed that VPA mice showed developmental delays as assessed with self-righting, eye opening tests and impaired social recognition. In addition, we provide the first evidence that primary cultured neurons from VPA-treated embryos present an increase in dendritic spines, compared with those from control mice. Mutations in phosphatase and tensin homolog (PTEN) gene are also known to be associated with autism, and mice with PTEN knockout show autistic characteristics. Protein expression of PTEN was decreased and the ratio of p-AKT/AKT was increased in the cerebral cortex and the hippocampus, and a distinctive anatomical change in the CA1 region of the hippocampus was observed. Taken together, our study suggests that prenatal exposure to VPA induces developmental delays and neuroanatomical changes via the reduction of PTEN level and these changes were detectable in the early days of life. PMID:27071011

  19. Comparative analyses of individual and multiple alterations of p53, PTEN and p16 in non-small cell lung carcinoma, glioma and breast carcinoma samples.

    PubMed

    Stankovic, Tijana; Milinkovic, Vedrana; Bankovic, Jasna; Dinic, Jelena; Tanic, Nasta; Dramicanin, Tatjana; Tanic, Nikola

    2014-06-01

    p53, p16 and PTEN are the most commonly altered tumor suppressor genes in human cancers. In the present study, we compared the presence of individual and multiple alterations of these tumor suppressors in non-small cell lung carcinoma (NSCLC), glioma and breast carcinoma, in order to evaluate specificity of each tumor type regarding the number of altered genes, as well as their combinations. We tested the mutational status, loss of heterozygosity and methylation status of these genes. Effects of gene alterations on patients' survival were also assessed. In NSCLC samples, single gene alterations occurred rarely, while there was considerable increase in incidence of double gene alterations. Furthermore, coexistence of aberrant p53, PTEN and p16 was the most frequent and had significant adverse effect on the survival of NSCLC patients. On the contrary, in glioma and breast cancer specimens, substantial number of cases had aberrant single gene only. Moreover, glioma and breast carcinoma also differ in genotypes that were predominant. Specifically, in glioma samples, prevalent were co-alterations of PTEN and p16, followed by aberrant only PTEN. In breast cancer samples, alterations in all three genes as well as in p53 and p16 were the most common. Moreover, PTEN was altered exclusively with aberrant p53, with statistically significant correlation among them. Overall, our results suggest that NSCLC, glioma and breast cancer need different approaches in molecular diagnosis and treatment with particular attention toward the number and combination of targeted genes. PMID:24767865

  20. EGFR- and AKT-mediated reduction in PTEN expression contributes to tyrphostin resistance and is reversed by mTOR inhibition in endometrial cancer cells.

    PubMed

    Li, Tian; Yang, Yuebo; Li, Xiaomao; Xu, Chengfang; Meng, Lirong

    2012-02-01

    Loss or mutation of the PTEN (phosphatase and tensin homologue deleted on chromosome 10) gene is associated with resistance to epidermal growth factor receptor (EGFR) inhibitors. However, the mechanism underlying remains elusive. In this study, we aimed to explore whether sensitivity to the EGFR tyrosine kinase inhibitor (TKI) is affected by PTEN status in endometrial cancer cells. PTEN siRNA and the PTEN gene were transfected into HEC-1A and Ishikawa endometrial cancer cells using lentiviral vectors. Cells were treated under various concentrations of RG14620 and rapamycin, which are EGFR and mammalian target of rapamycin (mTOR) inhibitors, respectively. The IC(50) of RG16420 was determined by using the MTT method. Cell apoptosis and the cell cycle were studied, and activation of EGFR, AKT, and p70S6 were detected by Western blot analysis. Loss of PTEN promoted cell proliferation and led to significant increases in the levels of EGFR, phospho-EGFR, AKT, phospho-AKT, and phospho-mTOR proteins. Ishikawa and HEC-1A(PTENkd) cells that displayed loss and inactivation of PTEN function were resistant to RG14620. HEC-1A and Ishikawa(PTEN) cells with intact PTEN were sensitive to RG14620. The combination of two inhibitors was more effective than both monotherapies, particularly in carcinoma cells with PTEN dysfunction. Decreased phospho-EGFR protein expression was observed in all cell lines that were sensitive to RG14620. Decreased phospho-AKT and phospho-p70S6 protein expression was observed in PTEN-intact cells that were sensitive to RG14620. PTEN loss results in resistance to EGFR TKI, which was reversed by PTEN reintroduction or mTOR inhibitor treatment. The combined treatment of EGFR TKI and the mTOR inhibitor provided a synergistic effect by promoting cell death in PTEN-deficient and PTEN-intact endometrial cancer cells, particularly in PTEN-deficient carcinoma cells with up-regulated EGFR activation.

  1. Evaluation of germline CDKN2A, ARF, CDK4, PTEN, and BRAF alterations in atypical mole syndrome.

    PubMed

    Celebi, J T; Ward, K M; Wanner, M; Polsky, D; Kopf, A W

    2005-01-01

    Atypical mole syndrome is a sporadic or an inherited condition with an increased risk of melanoma. Germline mutations in the CDKN2A, ARF, CDK4 and somatic mutations in the PTEN and BRAF genes have been associated with melanoma. In this study, we evaluated genes associated with familial and sporadic melanoma for mutations in 28 probands with the atypical mole syndrome. No sequence alterations in the coding regions or in the splice junctions of CDKN2A, ARF, CDK4, PTEN or BRAF were identified. These data suggest that genes evaluated in this study are unlikely to be candidate genes for atypical mole syndrome and support the notion that unknown susceptibility gene/s for this disease exist.

  2. Intact PTEN Expression by Immunohistochemistry is Associated With Decreased Survival in Advanced Stage Ovarian/Primary Peritoneal High-grade Serous Carcinoma.

    PubMed

    Bakkar, Rania M; Xie, Su-Su; Urbauer, Diana L; Djordjevic, Bojana; Vu, Kim; Broaddus, Russell R

    2015-11-01

    Ovarian high-grade serous carcinoma is an aggressive malignancy with poor prognosis. Optimal surgical debulking and tumor sensitivity to platinum-based chemotherapy are 2 well-established prognostics for this tumor type. Molecular markers that identify more clinically aggressive tumors would potentially allow for the development of individualized treatment options. PTEN is a key negative regulator of the PI3K signaling pathway. Loss of PTEN expression in endometrial carcinoma is associated with endometrioid histology; women with endometrioid tumors have a better prognosis than those with nonendometrioid tumors. The prognostic and predictive value for PTEN has not been effectively explored in ovarian/peritoneal high-grade serous carcinoma. PTEN immunohistochemistry was assessed in 126 women with Stage III, high-grade serous carcinoma of the ovary/peritoneum treated with surgery and then a platinum-based regimen. Compared with PTEN-negative or PTEN-reduced tumors, positive PTEN immunohistochemistry, detected in 58% of tumors, was associated with decreased pS6 and increased PTEN mRNA levels. Positive PTEN expression was independent of surgical debulking status or platinum sensitivity. PTEN-positive tumors were associated with significantly decreased recurrence-free survival. Importantly, the devised PTEN immunohistochemistry scoring system was reproducible among pathologists.

  3. Frequent loss of PTEN expression is linked to elevated phosphorylated Akt levels, but not associated with p27 and cyclin D1 expression, in primary epithelial ovarian carcinomas.

    PubMed

    Kurose, K; Zhou, X P; Araki, T; Cannistra, S A; Maher, E R; Eng, C

    2001-06-01

    PTEN (MMAC1/TEP1), a tumor suppressor gene on chromosome subband 10q23.3, is variably mutated and/or deleted in a variety of human cancers. Germline mutations in PTEN, which encode a dual-specificity phosphatase, have been implicated in at least two hamartoma tumor syndromes that exhibit some clinical overlap, Cowden syndrome and Bannayan-Riley-Ruvalcaba syndrome. Among several series of ovarian cancers, the frequency of loss of heterozygosity (LOH) of markers flanking and within PTEN, is approximately 30 to 50%, and the somatic intragenic PTEN mutation frequency is <10%. In this study, we screened primary adenocarcinomas of the ovary for LOH of polymorphic markers within and flanking the PTEN gene and for intragenic mutations of the PTEN gene and compared them to PTEN expression using immunohistochemistry. Furthermore, we sought to detect the expression of the presumed downstream targets of PTEN, such as P-Akt, p27, and cyclin D1 by immunohistochemistry. LOH at 10q23 was observed in 29 of 64 (45%) cases. Of the 117 samples, 6 somatic intragenic PTEN mutations, 1 germline mutation, and 1 novel polymorphism were found in 7 (6%) patients. Immunostaining of 49 ovarian cancer samples revealed that 13 (27%) were PTEN immunostain-negative, 25 (51%) had reduced staining, and the rest (22%) were PTEN expression-positive. Among the 44 informative tumors assessed for 10q23 LOH and PTEN immunostaining, there was an association between 10q23 LOH and decreased or absent staining (P = 0.0317). Of note, there were five (11%) tumors with neither mutation nor deletion that exhibited no PTEN expression and 10 (25%) others without mutation or deletion but had decreased PTEN expression. Among the 49 tumors available for immunohistochemistry, 28 (57%) showed P-Akt-positive staining, 24 (49%) had decreased p27 staining, and cyclin D1 was overexpressed in 35 (79%) cases. In general, P-Akt expression was inversely correlated with PTEN expression (P = 0.0083). These data suggest that

  4. MiR-19a regulates PTEN expression to mediate glycogen synthesis in hepatocytes.

    PubMed

    Dou, Lin; Meng, Xiangyu; Sui, Xiaofang; Wang, Shuyue; Shen, Tao; Huang, Xiuqing; Guo, Jun; Fang, Weiwei; Man, Yong; Xi, Jianzhong; Li, Jian

    2015-06-26

    MiR-19a, a member of mir-17-92 microRNA clusters, has been demonstrated to promote cell proliferation and angiogenesis via regulating the PI3K/AKT pathway, the major insulin signaling pathway. However, whether miR-19a plays an important role in glycogen synthesis in hepatocytes remains unknown. Here, we define the impact of miR-19a on glycogen synthesis and IL-6-induced reduced glycogenesis in hepatocytes and its underlying mechanisms. Our studies indicate that miR-19a was down-regulated in the livers of db/db mice and mice injected with IL-6, as well as mouse NCTC 1469 hepatocytes and HEP 1-6 hepatocytes treated by IL-6. We found that over-expression of miR-19a in NCTC 1469 cells and HEP 1-6 cells led to increased activation of the AKT/GSK pathway and synthesis of glycogen, whereas down-regulation of miR-19a impaired AKT/GSK phosphorylation and glycogenesis. Over-expression of miR-19a ameliorated IL-6-induced reduced glycogen synthesis in hepatocytes. Moreover, we identified PTEN as the target of miR-19a by a luciferase assay. Down-regulation of PTEN rescued the effects of miR-19a suppression on the activation of the AKT/GSK pathway and improved glycogenesis in NTC 1469 cells. These findings show for the first time that miR-19a might activate the AKT/GSK pathway and glycogenesis via down-regulation of PTEN expression.

  5. PTEN loss and HOXA10 expression are associated with ovarian endometrioid adenocarcinoma differentiation and progression.

    PubMed

    Tanwar, Pradeep S; Kaneko-Tarui, Tomoko; Lee, Ho-Joon; Zhang, Lihua; Teixeira, Jose M

    2013-04-01

    Epithelial ovarian cancer is a heterogeneous disease that is subdivided into five major histotypes but the mechanisms driving their differentiation are not clear. Mutations in adenomatous polyposis coli (APC) and β-catenin are commonly observed in the human ovarian endometrioid adenocarcinoma (OEA) patients. However, the mechanisms subsequent to APC deletion in ovarian tumorigenesis have not been well characterized. We have conditionally deleted APC in the murine ovarian surface epithelium (OSE) and showed that its loss leads to development of epithelial inclusion cysts. High-grade OEAs with tightly packed villoglandular histology were observed in older APC-deleted mice. Phosphatase and tensin homolog (PTEN) expression was elevated in the early lesions but lost after progression to the more advanced tumors. Knockdown of APC or expression of a gain-of-function β-catenin similarly induced human OSE cells to develop tumors with endometrioid histology in xenografts. Expression of HOXA10 was induced in both the advanced APC-deleted murine tumors and in the tumor xenografts of human OSE cells with knocked-down APC. These results show that reduced APC activity is sufficient to induce formation of epithelial inclusion cysts and support OEA development and suggest that induced HOXA10 expression and loss of PTEN are key mechanisms driving endometrioid histotype differentiation and progression.

  6. Loss of Pten Disrupts the Thymic Epithelium and Alters Thymic Function.

    PubMed

    Garfin, Phillip M; Nguyen, Thuyen; Sage, Julien

    2016-01-01

    The thymus is the site of T cell development and selection. In addition to lymphocytes, the thymus is composed of several types of stromal cells that are exquisitely organized to create the appropriate environment and microenvironment to support the development and selection of maturing T cells. Thymic epithelial cells (TECs) are one of the more important cell types in the thymic stroma, and they play a critical role in selecting functional T cell clones and supporting their development. In this study, we used a mouse genetics approach to investigate the consequences of deleting the Pten tumor suppressor gene in the TEC compartment of the developing thymus. We found that PTEN deficiency in TECs results in a smaller thymus with significantly disordered architecture and histology. Accordingly, loss of PTEN function also results in decreased T cells with a shift in the distribution of T cell subtypes towards CD8+ T cells. These experiments demonstrate that PTEN is critically required for the development of a functional thymic epithelium in mice. This work may help better understand the effects that certain medical conditions or clinical interventions have upon the thymus and immune function.

  7. Loss of Pten Disrupts the Thymic Epithelium and Alters Thymic Function.

    PubMed

    Garfin, Phillip M; Nguyen, Thuyen; Sage, Julien

    2016-01-01

    The thymus is the site of T cell development and selection. In addition to lymphocytes, the thymus is composed of several types of stromal cells that are exquisitely organized to create the appropriate environment and microenvironment to support the development and selection of maturing T cells. Thymic epithelial cells (TECs) are one of the more important cell types in the thymic stroma, and they play a critical role in selecting functional T cell clones and supporting their development. In this study, we used a mouse genetics approach to investigate the consequences of deleting the Pten tumor suppressor gene in the TEC compartment of the developing thymus. We found that PTEN deficiency in TECs results in a smaller thymus with significantly disordered architecture and histology. Accordingly, loss of PTEN function also results in decreased T cells with a shift in the distribution of T cell subtypes towards CD8+ T cells. These experiments demonstrate that PTEN is critically required for the development of a functional thymic epithelium in mice. This work may help better understand the effects that certain medical conditions or clinical interventions have upon the thymus and immune function. PMID:26914657

  8. PTEN posttranslational inactivation and hyperactivation of the PI3K/Akt pathway sustain primary T cell leukemia viability

    PubMed Central

    Silva, Ana; Yunes, J. Andrés; Cardoso, Bruno A.; Martins, Leila R.; Jotta, Patrícia Y.; Abecasis, Miguel; Nowill, Alexandre E.; Leslie, Nick R.; Cardoso, Angelo A.; Barata, Joao T.

    2008-01-01

    Mutations in the phosphatase and tensin homolog (PTEN) gene leading to PTEN protein deletion and subsequent activation of the PI3K/Akt signaling pathway are common in cancer. Here we show that PTEN inactivation in human T cell acute lymphoblastic leukemia (T-ALL) cells is not always synonymous with PTEN gene lesions and diminished protein expression. Samples taken from patients with T-ALL at the time of diagnosis very frequently showed constitutive hyperactivation of the PI3K/Akt pathway. In contrast to immortalized cell lines, most primary T-ALL cells did not harbor PTEN gene alterations, displayed normal PTEN mRNA levels, and expressed higher PTEN protein levels than normal T cell precursors. However, PTEN overexpression was associated with decreased PTEN lipid phosphatase activity, resulting from casein kinase 2 (CK2) overexpression and hyperactivation. In addition, T-ALL cells had constitutively high levels of ROS, which can also downmodulate PTEN activity. Accordingly, both CK2 inhibitors and ROS scavengers restored PTEN activity and impaired PI3K/Akt signaling in T-ALL cells. Strikingly, inhibition of PI3K and/or CK2 promoted T-ALL cell death without affecting normal T cell precursors. Overall, our data indicate that T-ALL cells inactivate PTEN mostly in a nondeletional, posttranslational manner. Pharmacological manipulation of these mechanisms may open new avenues for T-ALL treatment. PMID:18830414

  9. Relationship between expression and prognostic ability of PTEN, STAT3 and VEGF-C in colorectal cancer.

    PubMed

    Jin, Canhui; Wang, Aihong; Chen, Jianmin; Liu, Xiaomin; Wang, Gongping

    2012-10-01

    Expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN), signal transducer and activator of transcription-3 (STAT3) and vascular endothelial growth factor-C (VEGF-C) and their relationship with clinico-pathological features and prognostic ability was determined using immunohistochemistry in 68 cases of colorectal cancer with follow-up data. Kaplan-Meier survival analysis was performed and the prognostic value was determined using univariate analysis. PTEN, STAT3 and VEGF-C expression was detected in 32.4, 60.3 and 63.2% of colorectal carcinoma cases and 90.0, 0 and 0% of normal colon samples, respectively. PTEN and STAT3 were correlated with pathological grade (p=0.011, p=0.001, respectively), but not with tumor size, lymph node metastasis or clinical stage. VEGF-C was correlated with lymph node metastasis (p=0.002), but not with tumor size, pathological grade or clinical stage. Expression of STAT3 and VEGF-C was negatively correlated with PTEN (r=-0.402, r=-0.320, respectively), whereas STAT3 and VEGF-C expression was positively correlated with PTEN (r=0.254). The 3- and 5-year survival rates of PTEN protein-positive patients (68.1 and 50.0%, respectively) were significantly higher than those of PTEN protein-negative patients (32.6 and 19.6%, respectively; p=0.008). The 3- and 5-year survival rates of STAT3-positive (29.3 and 17.1%, respectively) were significantly lower than those of STAT3-negative patients (66.7 and 48.1%, respectively; p=0.005). The 3- and 5-year survival rates of VEGF-C-positive patients (29.3 and 17.1%, respectively) were significantly lower than the rates of VEGF-C-negative patients (66.7 and 48.1%, respectively; p=0.003, p=0.004, respectively). Multivariate analysis revealed that VEGF-C expression was an independent prognostic factor. In conclusion, this study indicates that PTEN, STAT3 and VEGF-C expression are beneficial prognostic factors, which may aid in the accurate assessment of prognosis and guide clinical

  10. Melittin Restores PTEN Expression by Down-Regulating HDAC2 in Human Hepatocelluar Carcinoma HepG2 Cells

    PubMed Central

    Huang, Cheng; Meng, Xiao-Ming; Bian, Er-Bao; Li, Jun

    2014-01-01

    Melittin is a water-soluble toxic peptide derived from the venom of the bee. Although many studies show the anti-tumor activity of melittin in human cancer including glioma cells, the underlying mechanisms remain elusive. Here the effect of melittin on human hepatocelluar carcinoma HepG2 cell proliferation in vitro and further mechanisms was investigated. We found melittin could inhibit cell proliferation in vitro using Flow cytometry and MTT method. Besides, we discovered that melittin significantly downregulated the expressions of CyclinD1 and CDK4. Results of western Blot and Real-time PCR analysis indicated that melittin was capable to upregulate the expression of PTEN and attenuate histone deacetylase 2 (HDAC2) expression. Further studies demonstrated that knockdown of HDAC2 completely mimicked the effects of melittin on PTEN gene expression. Conversely, it was that the potential utility of melittin on PTEN expression was reversed in cells treated with a recombinant pEGFP-C2-HDAC2 plasmid. In addition, treatment with melittin caused a downregulation of Akt phosphorylation, while overexpression of HDAC2 promoted Akt phosphorylation. These findings suggested that the inhibitory of cell growth by melittin might be led by HDAC2-mediated PTEN upregulation, Akt inactivation, and inhibition of the PI3K/Akt signaling pathways. PMID:24788349

  11. Deletion of Pten in CD45-expressing cells leads to development of T-cell lymphoblastic lymphoma but not myeloid malignancies

    PubMed Central

    Mirantes, Cristina; Dosil, Maria Alba; Hills, David; Yang, Jian; Eritja, Núria; Santacana, Maria; Gatius, Sònia; Vilardell, Felip; Medvinsky, Alexander; Matias-Guiu, Xavier

    2016-01-01

    Since its discovery in the late 1990s, Pten has turned out to be one of the most important tumor suppressor genes. Pten loss results in increased activation of the phosphatidylinositol 3-kinase/Akt signaling pathway, which is associated with increased proliferation, survival, and neoplastic growth. Here, we have addressed the effects of conditional deletion of Pten in hematopoietic cells by crossing Pten conditional knockout mice with a knock-in mouse expressing the Cre recombinase in the CD45 locus. CD45 is also known as leukocyte common antigen, and it is expressed in virtually all white cells and in hematopoietic stem cells. Using a reporter mouse, we demonstrate that CD45:Cre mouse displays recombinase activity in both myeloid and lymphoid cells. However, deletion of Pten in CD45-expressing cells induces development of T-cell acute lymphoblastic leukemia and lymphoma, but not other hematologic malignancies. PMID:26773036

  12. Impact of PTEN on the expression of insulin-like growth factors (IGFs) and IGF-binding proteins in human gastric adenocarcinoma cells

    SciTech Connect

    Yi, Ho-Keun; Kim, Sun-Young; Hwang, Pyoung-Han; Kim, Chan-Young; Yang, Doo-Hyun; Oh, Youngman; Lee, Dae-Yeol . E-mail: leedy@chonbuk.ac.kr

    2005-05-13

    PTEN is a tumor suppressor gene that is frequently mutated or deleted in a variety of human cancers including human gastric cancer. PTEN functions primarily as a lipid phosphatase and plays a key role in the regulation of the PI3 kinase/Akt pathway, thereby modulating cell proliferation and cell survival. On the other hand, the IGF system plays an important role in cell proliferation and cell survival via the PI3 kinase/Akt and MAP kinase pathways in many cancer cells. To characterize the impact of PTEN on the IGF-IGFR-IGFBP axis in gastric cancer, we overexpressed PTEN using an adenovirus gene transfer system in human gastric adenocarcinoma cells, SNU-484 and SNU-663, which lack PTEN. Overexpression of PTEN inhibited serum-induced as well as IGF-I-induced cell proliferation as compared to control cells. PTEN overexpression resulted in a significant decrease in the expression of IGF-I, -II, and IGF-IR. Interestingly, amongst the six IGFBPs, only IGFBP-3 was upregulated by PTEN, whereas IGFBP-4 and -6 were reduced. The IGFBP-3 promoter activity assay and Western immunoblotting demonstrate that PTEN regulates IGFBP-3 at the transcriptional level. In addition, the PI3 kinase inhibitor, LY294002, upregulates IGFBP-3 expression but downregulates IGF-I and IGF-II, indicating that PTEN controls IGFBP-3 and IGFs by an Akt-dependent pathway. These findings suggest that PTEN may inhibit antiapoptotic IGF actions not only by blocking the IGF-IGFR-induced Akt activity, but also by regulating expression of components of the IGF system, in particular, upregulation of IGFBP-3, which is known to exert antiproliferative effects through IGF-dependent and IGF-independent mechanisms in cancer cells.

  13. The tumor suppressor PTEN inhibits EGF-induced TSP-1 and TIMP-1 expression in FTC-133 thyroid carcinoma cells

    SciTech Connect

    Soula-Rothhut, Mahdhia; Coissard, Cyrille; Sartelet, Herve; Boudot, Cedric; Bellon, Georges; Martiny, Laurent; Rothhut, Bernard . E-mail: bernard.rothhut@univ-reims.fr

    2005-03-10

    Thrombospondin-1 (TSP-1) is a multidomain extracellular macromolecule that was first identified as natural modulator of angiogenesis and tumor growth. In the present study, we found that epidermal growth factor (EGF) up-regulated TSP-1 expression in FTC-133 (primary tumor) but not in FTC-238 (lung metastasis) thyroid cancer cells. Both EGF and TSP-1 induced expression of tissue inhibitor of metalloproteinase-1 (TIMP-1) in a mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) and phosphatidylinositol 3-kinase (PI3-kinase)-dependent manner. In FTC-133 cells, EGF induced proliferation in a TSP-1- and TIMP-1-dependent manner. In addition, we determined that re-expression of the tumor suppressor protein PTEN induced cell death, an effect that correlated with a block of Akt kinase phosphorylation. EGF-induced TSP-1 and TIMP-1 promoter activity and protein expression were inhibited in FTC-133 cells stably expressing wtPTEN but not in cells expressing mutant PTEN. Furthermore, we found that wtPTEN inhibited EGF-but not TSP-1-stimulated FTC-133 cell migration and also inhibited invasion induced by EGF and by TSP-1. Finally, an antibody against TSP-1 reversed EGF-stimulated FTC-133 cell invasion as well as the constitutive invasive potential of FTC-238 cells. Overall, our results suggest that PTEN can function as an important modulator of extracellular matrix proteins in thyroid cancer. Therefore, analyzing differential regulation of TSP-1 by growth factors such as EGF can be helpful in understanding thyroid cancer development.

  14. Subtle variations in Pten dose determine cancer susceptibility

    PubMed Central

    Alimonti, Andrea; Carracedo, Arkaitz; Clohessy, John G; Trotman, Lloyd C; Nardella, Caterina; Egia, Ainara; Salmena, Leonardo; Sampieri, Katia; Haveman, William J; Brogi, Edi; Richardson, Andrea L; Zhang, Jiangwen; Pandolfi, Pier Paolo

    2010-01-01

    Cancer susceptibility has been attributed to at least one heterozygous genetic alteration in a tumor suppressor gene (TSG)1. It has been hypothesized that subtle variations in TSG expression can promote cancer development2,3. However, this hypothesis has not yet been definitively supported in vivo. PTEN is a TSG frequently lost in human cancer and mutated in inherited cancer-predisposition syndromes4. Here, we analyze Pten hypermorphic mice (Ptenhy/+), expressing 80% normal levels of Pten. Ptenhy/+ mice develop a spectrum of tumors, with breast tumors occurring at the highest penetrance. All breast tumors analyzed here retained two intact copies of Pten and maintained Pten levels above heterozygosis. Notably, subtle downregulation of Pten altered the steady-state biology of the mammary tissues and the expression profiles of genes involved in cancer cell proliferation. We present an alterative working model for cancer development in which subtle reductions in the dose of TSGs predispose to tumorigenesis in a tissue-specific manner. PMID:20400965

  15. Focus on PTEN Regulation

    PubMed Central

    Bermúdez Brito, Miriam; Goulielmaki, Evangelia; Papakonstanti, Evangelia A.

    2015-01-01

    The role of phosphatase and tensin homolog on chromosome 10 (PTEN) as a tumor suppressor has been for a long time attributed to its lipid phosphatase activity against PI(3,4,5)P3, the phospholipid product of the class I PI3Ks. Besides its traditional role as a lipid phosphatase at the plasma membrane, a wealth of data has shown that PTEN can function independently of its phosphatase activity and that PTEN also exists and plays a role in the nucleus, in cytoplasmic organelles, and extracellularly. Accumulating evidence has shed light on diverse physiological functions of PTEN, which are accompanied by a complex regulation of its expression and activity. PTEN levels and function are regulated transcriptionally, post-transcriptionally, and post-translationally. PTEN is also sensitive to regulation by its interacting proteins and its localization. Herein, we summarize the current knowledge on mechanisms that regulate the expression and enzymatic activity of PTEN and its role in human diseases. PMID:26284192

  16. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) reduces vascular endothelial growth factor expression in allergen-induced airway inflammation.

    PubMed

    Lee, Kyung Sun; Kim, So Ri; Park, Seoung Ju; Lee, Ho Kyung; Park, Hee Sun; Min, Kyung Hoon; Jin, Sun Mi; Lee, Yong Chul

    2006-06-01

    Vascular endothelial growth factor (VEGF) plays a pivotal role in the pathogenesis of bronchial asthma. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) has been implicated in regulating cell survival signaling through the phosphoinositide 3-kinase (PI3K)/Akt pathway. The key role of PI3K in VEGF-mediated signal transduction is established. However, the effects of PTEN on VEGF-mediated signaling in asthma are unknown. This study aimed to determine the effect of PI3K inhibitors and PTEN on VEGF expression in allergen-induced airway inflammation. We have used a female C57BL/6 mouse model for asthma to determine the role of PTEN in allergen-induced airway inflammation, specifically in the expression of VEGF. Allergen-induced airway inflammation leads to increased activity of PI3K in lung tissue. These mice develop the following typical pathophysiological features of asthma in the lungs: increased numbers of inflammatory cells of the airways; airway hyper-responsiveness; increased expression of interleukin (IL)-4, IL-5, IL-13, intercellular adhesion molecule 1, vascular cell adhesion molecule 1, regulated on activation normal T cell expressed and secreted (RANTES), and eotaxin; increased vascular permeability; and increased levels of VEGF. Administration of PI3K inhibitors or adenoviruses carrying PTEN cDNA reduced the symptoms of asthma and decreased the increased levels of plasma extravasation and VEGF in allergen-induced asthmatic lungs. These results indicate that PTEN reduces VEGF expression in allergen-induced airway inflammation.

  17. Sodium butyrate induces differentiation of gastric cancer cells to intestinal cells via the PTEN/phosphoinositide 3-kinase pathway.

    PubMed

    Bai, Zhigang; Zhang, Zhongtao; Ye, Yingjiang; Wang, Shan

    2010-12-01

    NaB (sodium butyrate) inhibits cell proliferation and induces differentiation in a variety of tumour cells. In this study, we aimed to determine whether NaB induced differentiation and regulated the expression of the mucosal factor MUC2 through the PTEN/PI3K (phosphoinositide 3-kinase) pathway. BGC823 cells treated with NaB for 24-72 h showed marked inhibition of cell proliferation and alteration in cellular morphology. NaB treatment markedly increased the expression of PTEN and MUC2, but it decreased the expression of PI3K. These effects were enhanced by intervention with PI3K inhibitors and were reduced by intervention with PTEN siRNA. Hence, we conclude that NaB increased PTEN expression, promoted the expression of MUC2 and induced the differentiation of gastric cancer cells through the PTEN/PI3K signalling pathway.

  18. Mir-190b negatively contributes to the Trypanosoma cruzi- infected cell survival by repressing PTEN protein expression

    PubMed Central

    Monteiro, Cíntia Júnia; Mota, Suianne Letícia Antunes; Diniz, Lívia de Figueiredo; Bahia, Maria Terezinha; Moraes, Karen CM

    2015-01-01

    Chagas disease, which is caused by the intracellular protozoanTrypanosoma cruzi, is a serious health problem in Latin America. The heart is one of the major organs affected by this parasitic infection. The pathogenesis of tissue remodelling, particularly regarding cardiomyocyte behaviour after parasite infection, and the molecular mechanisms that occur immediately following parasite entry into host cells are not yet completely understood. Previous studies have reported that the establishment of parasitism is connected to the activation of the phosphatidylinositol-3 kinase (PI3K), which controls important steps in cellular metabolism by regulating the production of the second messenger phosphatidylinositol-3,4,5-trisphosphate. Particularly, the tumour suppressor PTEN is a negative regulator of PI3K signalling. However, mechanistic details of the modulatory activity of PTEN on Chagas disease have not been elucidated. To address this question, H9c2 cells were infected with T. cruzi Berenice 62 strain and the expression of a specific set of microRNAs (miRNAs) were investigated. Our cellular model demonstrated that miRNA-190b is correlated to the decrease of cellular viability rates by negatively modulating PTEN protein expression in T. cruzi-infected cells. PMID:26692329

  19. The mitogen-activated protein kinase (MAPK) cascade controls phosphatase and tensin homolog (PTEN) expression through multiple mechanisms.

    PubMed

    Ciuffreda, Ludovica; Di Sanza, Cristina; Cesta Incani, Ursula; Eramo, Adriana; Desideri, Marianna; Biagioni, Francesca; Passeri, Daniela; Falcone, Italia; Sette, Giovanni; Bergamo, Paola; Anichini, Andrea; Sabapathy, Kanaga; McCubrey, James A; Ricciardi, Maria Rosaria; Tafuri, Agostino; Blandino, Giovanni; Orlandi, Augusto; De Maria, Ruggero; Cognetti, Francesco; Del Bufalo, Donatella; Milella, Michele

    2012-06-01

    The mitogen-activated protein kinase (MAPK) and PI3K pathways are regulated by extensive crosstalk, occurring at different levels. In tumors, transactivation of the alternate pathway is a frequent "escape" mechanism, suggesting that combined inhibition of both pathways may achieve synergistic antitumor activity. Here we show that, in the M14 melanoma model, simultaneous inhibition of both MEK and mammalian target of rapamycin (mTOR) achieves synergistic effects at suboptimal concentrations, but becomes frankly antagonistic in the presence of relatively high concentrations of MEK inhibitors. This observation led to the identification of a novel crosstalk mechanism, by which either pharmacologic or genetic inhibition of constitutive MEK signaling restores phosphatase and tensin homolog (PTEN) expression, both in vitro and in vivo, and inhibits downstream signaling through AKT and mTOR, thus bypassing the need for double pathway blockade. This appears to be a general regulatory mechanism and is mediated by multiple mechanisms, such as MAPK-dependent c-Jun and miR-25 regulation. Finally, PTEN upregulation appears to be a major effector of MEK inhibitors' antitumor activity, as cancer cells in which PTEN is inactivated are consistently more resistant to the growth inhibitory and anti-angiogenic effects of MEK blockade. PMID:22215152

  20. Infrequent genetic alterations of the PTEN/MMAC1 gene in Japanese patients with primary cancers of the breast, lung, pancreas, kidney, and ovary.

    PubMed

    Sakurada, A; Suzuki, A; Sato, M; Yamakawa, H; Orikasa, K; Uyeno, S; Ono, T; Ohuchi, N; Fujimura, S; Horii, A

    1997-11-01

    In the present study, we searched for genetic alterations of the entire coding region of PTEN/MMAC1, a recently isolated candidate tumor suppressor gene, in 178 specimens from Japanese patients with various malignant tumors by the polymerase chain reaction-single strand conformation polymorphism method. The samples consisted of 11 glioblastoma multiformes (GBMs), 14 astrocytomas, 47 breast cancers, 25 non-small cell lung cancers, 9 small cell lung cancers, 8 pancreatic cancers, 24 renal cell carcinomas, 20 ovarian cancers, and 20 metastatic lung tumors from various organs. Only one somatic frameshift mutation at codon 319 was observed in one (9%) of eleven GBMs. Our results suggest that mutation of the PTEN/MMAC1 gene does not play a major role in carcinogenesis, at least in the tumor types from Japanese patients analyzed in this study.

  1. PTEN dosage is essential for neurofibroma development and malignant transformation.

    PubMed

    Gregorian, Caroline; Nakashima, Jonathan; Dry, Sarah M; Nghiemphu, P Leia; Smith, Kate Barzan; Ao, Yan; Dang, Julie; Lawson, Gregory; Mellinghoff, Ingo K; Mischel, Paul S; Phelps, Michael; Parada, Luis F; Liu, Xin; Sofroniew, Michael V; Eilber, Fritz C; Wu, Hong

    2009-11-17

    Patients with neurofibromatosis type 1 (NF1) carry approximately a 10% lifetime risk of developing a malignant peripheral nerve sheath tumor (MPNST). Although the molecular mechanisms underlying NF1 to MPNST malignant transformation remain unclear, alterations of both the RAS/RAF/MAPK and PI3K/AKT/mTOR signaling pathways have been implicated. In a series of genetically engineered murine models, we perturbed RAS/RAF/MAPK or/and PTEN/PI3K/AKT pathway, individually or simultaneously, via conditional activation of K-ras oncogene or deletion of Nf1 or Pten tumor suppressor genes. Only K-Ras activation in combination with a single Pten allele deletion led to 100% penetrable development of NF lesions and subsequent progression to MPNST. Importantly, loss or decrease in PTEN expression was found in all murine MPNSTs and a majority of human NF1-associated MPNST lesions, suggesting that PTEN dosage and its controlled signaling pathways are critical for transformation of NFs to MPNST. Using noninvasive in vivo PET-CT imaging, we demonstrated that FDG can be used to identify the malignant transformation in both murine and human MPNSTs. Our data suggest that combined inhibition of RAS/RAF/MAPK and PTEN/PI3K/AKT pathways may be beneficial for patients with MPNST. PMID:19846776

  2. PTEN dosage is essential for neurofibroma development and malignant transformation.

    PubMed

    Gregorian, Caroline; Nakashima, Jonathan; Dry, Sarah M; Nghiemphu, P Leia; Smith, Kate Barzan; Ao, Yan; Dang, Julie; Lawson, Gregory; Mellinghoff, Ingo K; Mischel, Paul S; Phelps, Michael; Parada, Luis F; Liu, Xin; Sofroniew, Michael V; Eilber, Fritz C; Wu, Hong

    2009-11-17

    Patients with neurofibromatosis type 1 (NF1) carry approximately a 10% lifetime risk of developing a malignant peripheral nerve sheath tumor (MPNST). Although the molecular mechanisms underlying NF1 to MPNST malignant transformation remain unclear, alterations of both the RAS/RAF/MAPK and PI3K/AKT/mTOR signaling pathways have been implicated. In a series of genetically engineered murine models, we perturbed RAS/RAF/MAPK or/and PTEN/PI3K/AKT pathway, individually or simultaneously, via conditional activation of K-ras oncogene or deletion of Nf1 or Pten tumor suppressor genes. Only K-Ras activation in combination with a single Pten allele deletion led to 100% penetrable development of NF lesions and subsequent progression to MPNST. Importantly, loss or decrease in PTEN expression was found in all murine MPNSTs and a majority of human NF1-associated MPNST lesions, suggesting that PTEN dosage and its controlled signaling pathways are critical for transformation of NFs to MPNST. Using noninvasive in vivo PET-CT imaging, we demonstrated that FDG can be used to identify the malignant transformation in both murine and human MPNSTs. Our data suggest that combined inhibition of RAS/RAF/MAPK and PTEN/PI3K/AKT pathways may be beneficial for patients with MPNST.

  3. MicroRNAome profiling in benign and malignant neurofibromatosis type 1-associated nerve sheath tumors: evidences of PTEN pathway alterations in early NF1 tumorigenesis

    PubMed Central

    2013-01-01

    Background Neurofibromatosis type 1 (NF1) is a common dominant tumor predisposition syndrome affecting 1 in 3,500 individuals. The hallmarks of NF1 are the development of peripheral nerve sheath tumors either benign (dermal and plexiform neurofibromas) or malignant (MPNSTs). Results To comprehensively characterize the role of microRNAs in NF1 tumorigenesis, we analyzed 377 miRNAs expression in a large panel of dermal and plexiform neurofibromas, and MPNSTs. The most significantly upregulated miRNA in plexiform neurofibromas was miR-486-3p that targets the major tumor suppressor gene, PTEN. We confirmed PTEN downregulation at mRNA level. In plexiform neurofibromas, we also report aberrant expression of four miRNAs involved in the RAS-MAPK pathway (miR-370, miR-143, miR-181a, and miR-145). In MPNSTs, significant deregulated miRNAs were involved in PTEN repression (miR-301a, miR-19a, and miR-106b), RAS-MAPK pathway regulation (Let-7b, miR-195, and miR-10b), mesenchymal transition (miR-200c, let-7b, miR-135a, miR-135b, and miR-9), HOX genes expression (miR-210, miR-196b, miR-10a, miR-10b, and miR-9), and cell cycle progression (miR-195, let-7b, miR-20a, miR-210, miR-129-3p, miR-449a, and miR-106b). Conclusion We confirmed the implication of PTEN in genesis of plexiform neurofibromas and MPNSTs in NF1. Markedly deregulated miRNAs might have potential diagnostic or prognostic value and could represent novel strategies for effective pharmacological therapies of NF1 tumors. PMID:23848554

  4. Analytic validation of a clinical-grade PTEN immunohistochemistry assay in prostate cancer by comparison with PTEN FISH.

    PubMed

    Lotan, Tamara L; Wei, Wei; Ludkovski, Olga; Morais, Carlos L; Guedes, Liana B; Jamaspishvili, Tamara; Lopez, Karen; Hawley, Sarah T; Feng, Ziding; Fazli, Ladan; Hurtado-Coll, Antonio; McKenney, Jesse K; Simko, Jeffrey; Carroll, Peter R; Gleave, Martin; Lin, Daniel W; Nelson, Peter S; Thompson, Ian M; True, Lawrence D; Brooks, James D; Lance, Raymond; Troyer, Dean; Squire, Jeremy A

    2016-08-01

    PTEN loss is a promising prognostic and predictive biomarker in prostate cancer. Because it occurs most commonly via PTEN gene deletion, we developed a clinical-grade, automated, and inexpensive immunohistochemical assay to detect PTEN loss. We studied the sensitivity and specificity of PTEN immunohistochemistry relative to four-color fluorescence in situ hybridization (FISH) for detection of PTEN gene deletion in a multi-institutional cohort of 731 primary prostate tumors. Intact PTEN immunostaining was 91% specific for the absence of PTEN gene deletion (549/602 tumors with two copies of the PTEN gene by FISH showed intact expression of PTEN by immunohistochemistry) and 97% sensitive for the presence of homozygous PTEN gene deletion (absent PTEN protein expression by immunohistochemistry in 65/67 tumors with homozygous deletion). PTEN immunohistochemistry was 65% sensitive for the presence of hemizygous PTEN gene deletion, with protein loss in 40/62 hemizygous tumors. We reviewed the 53 cases where immunohistochemistry showed PTEN protein loss and FISH showed two intact copies of the PTEN gene. On re-review, there was ambiguous immunohistochemistry loss in 6% (3/53) and failure to analyze the same tumor area by both methods in 34% (18/53). Of the remaining discordant cases, 41% (13/32) revealed hemizygous (n=8) or homozygous (n=5) PTEN gene deletion that was focal in most cases (11/13). The remaining 19 cases had two copies of the PTEN gene detected by FISH, representing truly discordant cases. Our automated PTEN immunohistochemistry assay is a sensitive method for detection of homozygous PTEN gene deletions. Immunohistochemistry screening is particularly useful to identify cases with heterogeneous PTEN gene deletion in a subset of tumor glands. Mutations, small insertions, or deletions and/or epigenetic or microRNA-mediated mechanisms may lead to PTEN protein loss in tumors with normal or hemizygous PTEN gene copy number.

  5. Expression of Somatostatin Receptor Type 2A and PTEN in Neuroendocrine Neoplasms Is Associated with Tumor Grade but Not with Site of Origin.

    PubMed

    Wada, Hideo; Matsuda, Katsuya; Akazawa, Yuko; Yamaguchi, Yuka; Miura, Shiro; Ueki, Nozomi; Kinoshita, Akira; Yoshiura, Koh-Ichiro; Kondo, Hisayoshi; Ito, Masahiro; Nagayasu, Takeshi; Nakashima, Masahiro

    2016-09-01

    Neuroendocrine neoplasms (NENs) are derived from endocrine cells in various organs and share common morphological features. This study aimed to clarify whether NENs of different organs are comparable at the molecular pathologic level. We retrospectively collected 99 cases of NENs from gastro-entero-pancreatic, lung, and other organs and reclassified these according to identical criteria. Grade, site, and molecular expression profile including NE markers, Ki-67, p53, somatostatin receptor type 2A (SSTR2A), and phosphatase and tensin homolog (PTEN) were compared. PTEN immunoreactivity was also compared with genomic copy number by fluorescence in situ hybridization (FISH) and droplet digital polymerase chain reaction (ddPCR). No significant differences were observed in the immunoreactivities of NE markers, p53, SSTR2A, or PTEN expression in NENs between the different organ sites. PTEN and p53 functional inactivation along with the loss of membranous SSTR2A expression appeared to be commonly involved in high-grade NEN. FISH results were significantly correlated with the level of PTEN immunoreactivity and with the findings of ddPCR analyses. The demonstration that these tumors are comparable at the molecular level will likely contribute to the broadening of therapeutic options such as the use of somatostatin analogues and mTOR inhibitors against NENs regardless of the affected organ, whereas molecular characterization of tumor grade will be useful for determining treatment strategy. PMID:27256098

  6. PTEN mutation and epidermal growth factor receptor activation regulate vascular endothelial growth factor (VEGF) mRNA expression in human glioblastoma cells by transactivating the proximal VEGF promoter.

    PubMed

    Pore, Nabendu; Liu, Shuang; Haas-Kogan, Daphne A; O'Rourke, Donald M; Maity, Amit

    2003-01-01

    Our previous work showed that, compared with parental U87MG human glioblastoma cells, vascular endothelial growth factor (VEGF) mRNA levels are decreased in U87/T691, a derivative line in which epidermal growth factor receptor (EGFR) signaling is inhibited by introduction of a truncated p185(Neu) protein (A. Maity et al., Cancer Res., 60: 5879-5886, 2000). The effect of EGFR activation on VEGF was mediated at the level of transcription via a phosphatidylinositol 3'-kinase (PI3K)-dependent pathway. In the current study we investigated the effect of PTEN, a negative regulator of PI3K signaling commonly mutated in glioblastoma cells, on VEGF expression. Several glioblastoma cell lines containing mutant PTEN, including U87MG, U87/T691, and U251MG, were infected with adenovirus expressing wild-type PTEN. This led to a decrease in the levels of both VEGF mRNA and phosphorylated Akt, a marker for PI3K activation. Treatment of U87MG cells with LY294002, a PI3K inhibitor, or cotransfection with a vector expressing wild-type PTEN decreased VEGF promoter activity using reporters containing either 1.5 kb of the promoter or a fragment extending from -88 to +54 bp. Activity of the -88/+54 VEGF promoter was down-regulated by dominant negative Akt and up-regulated by constitutively active myristoylated Akt. Introduction of wild-type PTEN and pharmacological inhibition of EGFR decreased VEGF mRNA expression and VEGF promoter activity in U87MG cells to a greater extent that did either manipulation by itself. Therefore, in human glioblastoma cells, PTEN mutation can cooperate with EGFR activation to increase VEGF mRNA levels by transcriptionally up-regulating the proximal VEGF promoter via the PI3K/Akt pathway.

  7. PTEN: Multiple Functions in Human Malignant Tumors

    PubMed Central

    Milella, Michele; Falcone, Italia; Conciatori, Fabiana; Cesta Incani, Ursula; Del Curatolo, Anais; Inzerilli, Nicola; Nuzzo, Carmen M. A.; Vaccaro, Vanja; Vari, Sabrina; Cognetti, Francesco; Ciuffreda, Ludovica

    2015-01-01

    PTEN is the most important negative regulator of the PI3K signaling pathway. In addition to its canonical, PI3K inhibition-dependent functions, PTEN can also function as a tumor suppressor in a PI3K-independent manner. Indeed, the PTEN network regulates a broad spectrum of biological functions, modulating the flow of information from membrane-bound growth factor receptors to nuclear transcription factors, occurring in concert with other tumor suppressors and oncogenic signaling pathways. PTEN acts through its lipid and protein phosphatase activity and other non-enzymatic mechanisms. Studies conducted over the past 10 years have expanded our understanding of the biological role of PTEN, showing that in addition to its ability to regulate proliferation and cell survival, it also plays an intriguing role in regulating genomic stability, cell migration, stem cell self-renewal, and tumor microenvironment. Changes in PTEN protein levels, location, and enzymatic activity through various molecular mechanisms can generate a continuum of functional PTEN levels in inherited syndromes, sporadic cancers, and other diseases. PTEN activity can indeed, be modulated by mutations, epigenetic silencing, transcriptional repression, aberrant protein localization, and post-translational modifications. This review will discuss our current understanding of the biological role of PTEN, how PTEN expression and activity are regulated, and the consequences of PTEN dysregulation in human malignant tumors. PMID:25763354

  8. Active TGF-β signaling and decreased expression of PTEN separates angiosarcoma of bone from its soft tissue counterpart.

    PubMed

    Verbeke, Sofie L J; Bertoni, Franco; Bacchini, Patrizia; Oosting, Jan; Sciot, Raf; Krenács, Tibor; Bovée, Judith V M G

    2013-09-01

    Angiosarcomas constitute a heterogeneous group of highly malignant vascular tumors. Angiosarcoma of bone is rare and poorly characterized. For angiosarcoma of soft tissue, some pathways seem to be involved in tumor development. Our aim was to evaluate the role of these pathways in angiosarcoma of bone. We collected 37 primary angiosarcomas of bone and used 20 angiosarcomas of soft tissue for comparison. Immunohistochemistry was performed on constructed tissue microarrays to evaluate expression of CDKN2A, TP53, PTEN, BCL2, CDK4, MDM2, cyclin D1, β-catenin, transforming growth factor-β (TGF-β), CD105, phospho-Smad1, phospho-Smad2, hypoxia-inducible factor-1α, plasminogen activator inhibitor type 1 (PAI-1), VEGF, CD117 and glucose transporter--1. PIK3CA was screened for hotspot mutations in 19 angiosarcomas. In nearly 55% of the angiosarcoma of bone, the retinoblastoma (Rb) pathway was affected. Loss of CDKN2A expression was associated with a significantly worse prognosis. No overexpression of TP53 or MDM2 was found, suggesting that the TP53 pathway is not important in angiosarcoma of bone. Angiosarcoma of bone showed highly active TGF-β signaling with immunoreactivity for phospho-Smad2 and PAI-1. Although the phosphatidylinositol 3-kinase (PI3K)/Akt pathway seems to be active in both tumor groups, different mechanisms were involved: 41% of angiosarcoma of bone showed a decrease in expression of PTEN, whereas in angiosarcoma of soft tissue overexpression of KIT was found (90%). PIK3CA hotspot mutations were absent. In conclusion, the Rb pathway is involved in tumorigenesis of angiosarcoma of bone. The PI3K/Akt pathway is activated in both angiosarcoma of bone and soft tissue, however, with a different cause; PTEN expression is decreased in angiosarcoma of bone, whereas angiosarcomas of soft tissue show overexpression of KIT. Our findings support that angiosarcomas are a heterogeneous group of vascular malignancies. Both angiosarcoma of bone and soft tissue may

  9. EGFR protein expression using a specific intracellular domain antibody and PTEN and clinical outcomes in squamous cell lung cancer patients with EGFR-tyrosine kinase inhibitor therapy

    PubMed Central

    Chang, Hyun; Oh, Jisu; Zhang, Xianglan; Kim, Yu Jung; Lee, Jae Ho; Lee, Choon-Taek; Chung, Jin-haeng; Lee, Jong-Seok

    2016-01-01

    Purpose The aim of this research was to examine the molecular and clinical features that are related with EGFR-tyrosine kinase inhibitor (EGFR-TKI) efficacy in previously treated patients with squamous cell carcinoma of the lung (SCCL). Materials and methods This retrospective study included 67 SCCL patients with obtainable lung cancer tissue and records on EGFR-TKI treatment response and survival. EGFR protein expression in lung cancer tissue was measured by immunohistochemistry with a specific antibody that recognizes the intracellular domain (ID) of EGFR. PTEN expression in lung cancer tissue was also evaluated with immunohistochemistry. PI3KCA gene amplification was detected by quantitative real-time polymerase chain reaction, and FGFR1 amplification was assessed by fluorescent in situ hybridization. Results EGFR ID expression (hazard ratio [HR] 0.53, P=0.022) and Eastern Cooperative Oncology Group (ECOG) performance status (PS) (HR 0.43, P=0.022) were significantly related with progression-free survival following EGFR-TKIs treatment. PTEN expression (HR 0.52, P=0.025) was significantly related to overall survival. The group of EGFR-positive or PTEN-positive patients with ECOG PS of 0 or 1 had better clinical outcomes than patients who were EGFR-negative and PTEN-negative or who had poor ECOG PS with longer median progression-free survival (2.1 vs 1.0 months, P=0.05) and overall survival (6.2 vs 2.1 months, P=0.05). Conclusion EGFR expression using an ID-specific antibody and PTEN protein expression may be used to identify SCCL patients who might benefit from EGFR-TKI treatment. PMID:27578983

  10. KRAS and BRAF Mutations and PTEN Expression Do Not Predict Efficacy of Cetuximab-Based Chemoradiotherapy in Locally Advanced Rectal Cancer

    SciTech Connect

    Erben, Philipp; Stroebel, Philipp; Horisberger, Karoline; Popa, Juliana; Bohn, Beatrice; Hanfstein, Benjamin; Kaehler, Georg; Kienle, Peter; Post, Stefan; Wenz, Frederik; Hochhaus, Andreas

    2011-11-15

    Purpose: Mutations in KRAS and BRAF genes as well as the loss of expression of phosphatase and tensin homolog (PTEN) (deleted on chromosome 10) are associated with impaired activity of antibodies directed against epidermal growth factor receptor in patients with metastatic colorectal cancer. The predictive and prognostic value of the KRAS and BRAF point mutations as well as PTEN expression in patients with locally advanced rectal cancer (LARC) treated with cetuximab-based neoadjuvant chemoradiotherapy is unknown. Methods and Materials: We have conducted phase I and II trials of the combination of weekly administration of cetuximab and irinotecan and daily doses of capecitabine in conjunction with radiotherapy (45 Gy plus 5.4 Gy) in patients with LARC (stage uT3/4 or uN+). The status of KRAS and BRAF mutations was determined with direct sequencing, and PTEN expression status was determined with immunohistochemistry testing of diagnostic tumor biopsies. Tumor regression was evaluated by using standardized regression grading, and disease-free survival (DFS) was calculated according to the Kaplan-Meier method. Results: A total of 57 patients were available for analyses. A total of 31.6% of patients carried mutations in the KRAS genes. No BRAF mutations were found, while the loss of PTEN expression was observed in 9.6% of patients. Six patients achieved complete remission, and the 3-year DFS rate was 73%. No correlation was seen between tumor regression or DFS rate and a single marker or a combination of all markers. Conclusions: In the present series, no BRAF mutation was detected. The presence of KRAS mutations and loss of PTEN expression were not associated with impaired response to cetuximab-based chemoradiotherapy and 3-year DFS.

  11. PTEN enhances the sensitivity of human hepatocellular carcinoma cells to sorafenib.

    PubMed

    Ruan, Zhi-Ping; Xu, Rui; Lv, Yi; Tian, Tao; Wang, Wen-Juan; Guo, Hui; Nan, Ke-Jun

    2012-01-01

    Hepatocellular carcinoma (HCC) is a complex and heterogeneous tumor with several genomic alterations and ranks as the third highest cause of cancer-related death globally. The unresectable or metastatic HCC has very poor prognosis. Although multikinase inhibitor sorafenib can increase the survival of patients with advanced HCC, it is becoming apparent that combination therapies are critical to overcome the complex genomic aberrations in HCC. PTEN, as one of the most commonly inactivated genes in HCC, exerts a wide range of antitumor effects. In this study, we found that PTEN was downregulated in HCC tissues, especially in those tissues with extrahepatic metastasis. And negative PTEN expression cases showed increased proliferation activity. Overexpression of PTEN significantly reduced the proliferation of tumor cells HepG2. In addition, HepG2 cells transfected with PTEN were more sensitive to sorafenib in terms of its ability to inhibit proliferation and to induce apoptosis. Moreover, overexpression of PTEN decreased phosphorylation of MEK, a key downstream effector of RAF/MEK/ERK cascade, and levels of cyclin D1, antiapoptotic Bcl-2, and VEGF. These observations indicated that combination therapies with sorafenib and PTEN overexpression have potential to further improve therapeutic options for HCC.

  12. Behavioral abnormalities in mice lacking mesenchyme-specific Pten.

    PubMed

    Borniger, Jeremy C; Cissé, Yasmine M; Cantemir-Stone, Carmen Z; Bolon, Brad; Nelson, Randy J; Marsh, Clay B

    2016-05-01

    Phosphatase and tensin homolog (Pten) is a negative regulator of cell proliferation and growth. Using a Cre-recombinase approach with Lox sequences flanking the fibroblast-specific protein 1 (Fsp1 aka S100A4; a mesenchymal marker), we probed sites of expression using a β-galactosidase Rosa26(LoxP) reporter allele; the transgene driving deletion of Pten (exons 4-5) was found throughout the brain parenchyma and pituitary, suggesting that deletion of Pten in Fsp1-positive cells may influence behavior. Because CNS-specific deletion of Pten influences social and anxiety-like behaviors and S100A4 is expressed in astrocytes, we predicted that loss of Pten in Fsp1-expressing cells would result in deficits in social interaction and increased anxiety. We further predicted that environmental enrichment would compensate for genetic deficits in these behaviors. We conducted a battery of behavioral assays on Fsp1-Cre;Pten(LoxP/LoxP) male and female homozygous knockouts (Pten(-/-)) and compared their behavior to Pten(LoxP/LoxP) (Pten(+/+)) conspecifics. Despite extensive physical differences (including reduced hippocampal size) and deficits in sensorimotor function, Pten(-/-) mice behaved remarkably similar to control mice on nearly all behavioral tasks. These results suggest that the social and anxiety-like phenotypes observed in CNS-specific Pten(-/-) mice may depend on neuronal Pten, as lack of Pten in Fsp1-expressing cells of the CNS had little effect on these behaviors.

  13. Somatic Copy Number Alterations at Oncogenic Loci Show Diverse Correlations with Gene Expression

    NASA Astrophysics Data System (ADS)

    Roszik, Jason; Wu, Chang-Jiun; Siroy, Alan E.; Lazar, Alexander J.; Davies, Michael A.; Woodman, Scott E.; Kwong, Lawrence N.

    2016-01-01

    Somatic copy number alterations (SCNAs) affecting oncogenic drivers have a firmly established role in promoting cancer. However, no agreed-upon standard exists for calling locus-specific amplifications and deletions in each patient sample. Here, we report the correlative analysis of copy number amplitude and length with gene expression across 6,109 samples from The Cancer Genome Atlas (TCGA) dataset across 16 cancer types. Using specificity, sensitivity, and precision-based scores, we assigned optimized amplitude and length cutoffs for nine recurrent SCNAs affecting known oncogenic drivers, using mRNA expression as a functional readout. These cutoffs captured the majority of SCNA-driven, highly-expression-altered samples. The majority of oncogenes required only amplitude cutoffs, as high amplitude samples were almost invariably focal; however, CDKN2A and PTEN uniquely required both amplitude and length cutoffs as primary predictors. For PTEN, these extended to downstream AKT activation. In contrast, SCNA genes located peri-telomerically or in fragile sites showed poor expression-copy number correlations. Overall, our analyses identify optimized amplitude and length cutoffs as efficient predictors of gene expression changes for specific oncogenic SCNAs, yet warn against one-size-fits-all interpretations across all loci. Our results have implications for cancer data analyses and the clinic, where copy number and mutation data are increasingly used to personalize cancer therapy.

  14. Somatic Copy Number Alterations at Oncogenic Loci Show Diverse Correlations with Gene Expression

    PubMed Central

    Roszik, Jason; Wu, Chang-Jiun; Siroy, Alan E.; Lazar, Alexander J.; Davies, Michael A; Woodman, Scott E; Kwong, Lawrence N

    2016-01-01

    Somatic copy number alterations (SCNAs) affecting oncogenic drivers have a firmly established role in promoting cancer. However, no agreed-upon standard exists for calling locus-specific amplifications and deletions in each patient sample. Here, we report the correlative analysis of copy number amplitude and length with gene expression across 6,109 samples from The Cancer Genome Atlas (TCGA) dataset across 16 cancer types. Using specificity, sensitivity, and precision-based scores, we assigned optimized amplitude and length cutoffs for nine recurrent SCNAs affecting known oncogenic drivers, using mRNA expression as a functional readout. These cutoffs captured the majority of SCNA-driven, highly-expression-altered samples. The majority of oncogenes required only amplitude cutoffs, as high amplitude samples were almost invariably focal; however, CDKN2A and PTEN uniquely required both amplitude and length cutoffs as primary predictors. For PTEN, these extended to downstream AKT activation. In contrast, SCNA genes located peri-telomerically or in fragile sites showed poor expression-copy number correlations. Overall, our analyses identify optimized amplitude and length cutoffs as efficient predictors of gene expression changes for specific oncogenic SCNAs, yet warn against one-size-fits-all interpretations across all loci. Our results have implications for cancer data analyses and the clinic, where copy number and mutation data are increasingly used to personalize cancer therapy. PMID:26787600

  15. PTEN and p16 genes as epigenetic biomarkers in oral squamous cell carcinoma (OSCC): a study on south Indian population.

    PubMed

    Sushma, P S; Jamil, Kaiser; Kumar, P Uday; Satyanarayana, U; Ramakrishna, M; Triveni, B

    2016-06-01

    Phosphatase and tensin homolog (PTEN) and p16INK4a (p16) genes are tumor suppressor genes, associated with epigenetic alterations. PTEN and p16 promoter hypermethylation is a major epigenetic silencing mechanism leading to cancer. The cooperation between PTEN and p16 in pathogenesis of cancers suggest that their combination might be considered as potential molecular marker for specific subgroups of patients. Hence, the present study aimed to investigate whether PTEN and p16 promoter methylations were involved in oral squamous cell carcinoma (OSCC) in south Indian subjects. DNA methylation quantitative analyses of the two candidate tumor suppressor genes PTEN and p16 were performed by methylation-specific polymerase chain reaction (MSP). Fifty OSCC biopsy samples and their corresponding non-malignant portions as controls were studied comparatively. The methylation status was correlated with the clinical manifestations. Twelve out of 50 patients (24 %) were found to be methylated for PTEN gene, whereas methylation of the p16 gene occurred in 19 out of 50 cases (38 %). A statistically significant result was obtained (P = <0.0001 and 0.017) for both PTEN and p16 genes. PTEN and p16 promoter methylation may be the main mechanism leading to the low expression of PTEN and p16 genes indicating the progress of tumor development. Our data suggest that a low PTEN and p16 expression due to methylation may contribute to the cancer progression and could be useful for prognosis of OSCC. Therefore, analysis of promoter methylation in such genes may provide a biomarker valuable for early detection of oral cancer.

  16. Effects of mir-21 on Cardiac Microvascular Endothelial Cells After Acute Myocardial Infarction in Rats: Role of Phosphatase and Tensin Homolog (PTEN)/Vascular Endothelial Growth Factor (VEGF) Signal Pathway

    PubMed Central

    Yang, Feng; Liu, Wenwei; Yan, Xiaojuan; Zhou, Hanyun; Zhang, Hongshen; Liu, Jianfei; Yu, Ming; Zhu, Xiaoshan; Ma, Kezhong

    2016-01-01

    Background This study investigated how miR-21 expression is reflected in acute myocardial infarction and explored the role of miR-21 and the PTEN/VEGF signaling pathway in cardiac microvascular endothelial cells. Material/Methods We used an in vivo LAD rat model to simulate acute myocardial infarction. MiR-21 mimics and miR-21 inhibitors were injected and transfected into model rats in order to alter miR-21 expression. Cardiac functions were evaluated using echocardiographic measurement, ELISA, and Masson staining. In addition, lenti-PTEN and VEGF siRNA were transfected into CMEC cells using standard procedures for assessing the effect of PTEN and VEGE on cell proliferation, apoptosis, and angiogenesis. MiR-21, PTEN, and VEGF expressions were examined by RT-PCR and Western blot. The relationship between miR-21 and PTEN was determined by the luciferase activity assay. Results We demonstrated that miR-21 bonded with the 3′-UTR of PTEN and suppressed PTEN expressions. Established models significantly induced cardiac infarct volume and endothelial injury marker expressions as well as miR-21 and PTEN expressions (P<0.05). MiR-21 mimics exhibited significantly protective effects since they down-regulated both infarction size and injury marker expressions by increasing VEGF expression and inhibiting PTEN expression (P<0.05). In addition, results from in vitro research show that lenti-PTEN and VEGF siRNA can notably antagonize the effect of miR-21 on cell proliferation, apoptosis, and angiogenesis (P<0.05). Conclusions MiR-21 exerts protective effects on endothelial injury through the PTEN/VEGF pathway after acute myocardial infarction. PMID:27708252

  17. The Anti-proliferative Response of Indole-3-carbinol in human melanoma cells is Triggered by an Interaction with NEDD4-1 and Disruption of Wild-type PTEN Degradation

    PubMed Central

    Quirit, Jeanne G.; Firestone, Gary L.

    2014-01-01

    Human melanoma cells displaying distinct PTEN genotypes were used to assess the cellular role of this important tumor suppressor protein during the anti-proliferative response induced by the chemopreventative agent indole-3-carbinol (I3C), a natural indolecarbinol compound derived from the breakdown of glucobrassicin produced in cruciferous vegetables such as broccoli and Brussels sprouts. I3C induced a G1-phase cell cycle arrest and apoptosis by stabilization of PTEN in human melanoma cells that express wild-type PTEN, but not in cells with mutant or null PTEN genotypes. Importantly, normal human epidermal melanocytes were unaffected by I3C treatment. In wild-type PTEN-expressing melanoma xenografts, formed in athymic mice, I3C inhibited the in vivo tumor growth rate and increased PTEN protein levels in the residual tumors. Mechanistically, I3C disrupted the ubiquitination of PTEN by NEDD4-1 (NEDD4), which prevented the proteasome-mediated degradation of PTEN without altering its transcript levels. RNAi-mediated knockdown of PTEN prevented the I3C induced apoptotic response; whereas, knockdown of NEDD4-1 mimicked the I3C apoptotic response, stabilized PTEN protein levels and down-regulated phosphorylated AKT1 levels. Co-knockdown of PTEN and NEDD4-1 revealed that I3C regulated apoptotic signaling through NEDD4-1 requires the presence of the wild-type PTEN protein. Finally, in silico structural modeling in combination with isothermal titration calorimetry analysis demonstrated that I3C directly interacts with purified NEDD4-1 protein. Implications This study identifies NEDD4-1 as a new I3C target protein, and that the I3C disruption of NEDD4-1 ubiquitination activity triggers the stabilization of the wild-type PTEN tumor suppressor to induce an anti-proliferative response in melanoma. PMID:25009292

  18. Impact of PTEN Protein Expression on Benefit From Adjuvant Trastuzumab in Early-Stage Human Epidermal Growth Factor Receptor 2–Positive Breast Cancer in the North Central Cancer Treatment Group N9831 Trial

    PubMed Central

    Perez, Edith A.; Dueck, Amylou C.; McCullough, Ann E.; Chen, Beiyun; Geiger, Xochiquetzal J.; Jenkins, Robert B.; Lingle, Wilma L.; Davidson, Nancy E.; Martino, Silvana; Kaufman, Peter A.; Kutteh, Leila A.; Sledge, George W.; Harris, Lyndsay N.; Gralow, Julie R.; Reinholz, Monica M.

    2013-01-01

    Purpose It has been suggested that PTEN, a negative regulator of PI3K/AKT signaling, is involved in tumor sensitivity to trastuzumab. We investigated the association between tumor PTEN protein expression and disease-free survival (DFS) of patients randomly assigned to receive chemotherapy alone (arm A) or chemotherapy with sequential (arm B) or concurrent trastuzumab (arm C) in the phase III early-stage human epidermal growth factor receptor 2 (HER2) –positive trial—North Central Cancer Treatment Group (NCCTG) N9831. Patients and Methods The intensity and percentage of invasive cells with cytoplasmic PTEN staining were determined in tissue microarray sections containing three cores per block (n = 1,286) or in whole tissue sections (WS; n = 516) by using standard immunohistochemistry (138G6 monoclonal antibody). Tumors were considered positive for PTEN (PTEN-positive) if any core or WS had any invasive cells with ≥ 1+ staining. Median follow-up was 6.0 years. Results Of 1,802 patients included in this analysis (of 3,505 patients registered to N9831), 1,342 (74%) had PTEN-positive tumors. PTEN positivity was associated with hormone receptor negativity (χ2 P < .001) and nodal positivity (χ2 P = .04). PTEN did not have an impact on DFS within the various arms. Comparing DFS of arm C to arm A, patients with PTEN-positive and PTEN-negative tumors had hazard ratios (HRs) of 0.65 (P = .003) and 0.47 (P = .005), respectively (interaction P = .16). For arm B versus arm A, patients with PTEN-positive and PTEN-negative tumors had HRs of 0.70 (P = .009) and 0.85 (P = .44), respectively (interaction P = .47). Conclusion In contrast to selected preclinical and limited clinical studies suggesting a decrease in trastuzumab sensitivity in patients with PTEN-negative tumors, our data show benefit of adjuvant trastuzumab for patients with HER2-positive breast cancer, independent of tumor PTEN status. PMID:23650412

  19. Convergent loss of PTEN leads to clinical resistance to a PI(3)Kα inhibitor.

    PubMed

    Juric, Dejan; Castel, Pau; Griffith, Malachi; Griffith, Obi L; Won, Helen H; Ellis, Haley; Ebbesen, Saya H; Ainscough, Benjamin J; Ramu, Avinash; Iyer, Gopa; Shah, Ronak H; Huynh, Tiffany; Mino-Kenudson, Mari; Sgroi, Dennis; Isakoff, Steven; Thabet, Ashraf; Elamine, Leila; Solit, David B; Lowe, Scott W; Quadt, Cornelia; Peters, Malte; Derti, Adnan; Schegel, Robert; Huang, Alan; Mardis, Elaine R; Berger, Michael F; Baselga, José; Scaltriti, Maurizio

    2015-02-12

    Broad and deep tumour genome sequencing has shed new light on tumour heterogeneity and provided important insights into the evolution of metastases arising from different clones. There is an additional layer of complexity, in that tumour evolution may be influenced by selective pressure provided by therapy, in a similar fashion to that occurring in infectious diseases. Here we studied tumour genomic evolution in a patient (index patient) with metastatic breast cancer bearing an activating PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha, PI(3)Kα) mutation. The patient was treated with the PI(3)Kα inhibitor BYL719, which achieved a lasting clinical response, but the patient eventually became resistant to this drug (emergence of lung metastases) and died shortly thereafter. A rapid autopsy was performed and material from a total of 14 metastatic sites was collected and sequenced. All metastatic lesions, when compared to the pre-treatment tumour, had a copy loss of PTEN (phosphatase and tensin homolog) and those lesions that became refractory to BYL719 had additional and different PTEN genetic alterations, resulting in the loss of PTEN expression. To put these results in context, we examined six other patients also treated with BYL719. Acquired bi-allelic loss of PTEN was found in one of these patients, whereas in two others PIK3CA mutations present in the primary tumour were no longer detected at the time of progression. To characterize our findings functionally, we examined the effects of PTEN knockdown in several preclinical models (both in cell lines intrinsically sensitive to BYL719 and in PTEN-null xenografts derived from our index patient), which we found resulted in resistance to BYL719, whereas simultaneous PI(3)K p110β blockade reverted this resistance phenotype. We conclude that parallel genetic evolution of separate metastatic sites with different PTEN genomic alterations leads to a convergent PTEN-null phenotype resistant

  20. PTEN methylation involved in benzene-induced hematotoxicity.

    PubMed

    Yang, Jing; Zuo, Xin; Bai, Wenlin; Niu, Piye; Tian, Lin; Gao, Ai

    2014-06-01

    It is well known that benzene is a hematotoxic carcinogen. PTEN promoter methylation is a representative example of transcriptional silencing of tumor suppressor genes. However, the effect of PTEN methylation on benzene-induced hematotoxicity has not yet been elucidated. In this study, the animal model of benzene hematotoxicity was successfully established. WBC significantly decreased in experimental groups (P < 0.01). Compared with the control group, the weight of rats increased slowly and even declined with increasing doses of benzene in the benzene-treated groups. An increase in the level of PTEN methylation was observed in the low dose group, and PTEN methylation level increased significantly in a dose-dependent manner. However, it was interesting that PTEN mRNA expression increased in the low dose group, but declined with increasing doses of benzene. The decrease of tumor suppressor function caused by PTEN methylation may be an important mechanism of benzene hematotoxicity. Furthermore, lymphoblast cell line F32 was incubated by benzene and then treated with 5-aza and TSA, alone or in combination. A dramatic decrease in the PTEN mRNA expression and a significant increase of PTEN methylation level in benzene-treated cells were also shown. PTEN mRNA expression was up regulated and PTEN methylation level was reduced by the epigenetic inhibitors, 5-aza and TSA. In conclusion, PTEN methylation is involved in benzene-induced hematotoxicity through suppressing PTEN mRNA expression.

  1. Tetramethylpyrazine enhances functional recovery after contusion spinal cord injury by modulation of MicroRNA-21, FasL, PDCD4 and PTEN expression.

    PubMed

    Huang, Jiang-Hu; Cao, Yong; Zeng, Lei; Wang, Guan; Cao, Min; Lu, Hong-Bin; Hu, Jian-Zhong

    2016-10-01

    Our previous study showed Tetramethylpyrazine (TMP) has protective effects against SCI. In this study, we aimed to uncover the mechanism underlying the protective effects of TMP in SCI. SCI was induced in Sprague-Dawley rats with a modified weight-drop device. One group was subjected to SCI in combination with TMP administration at a dose of 200mg/kgd, for 3 days. Concurrently, another group received SCI in combination with an equal volume of 0.9% saline. Locomotor functional recovery was assessed during the 4 weeks post-injury by performing the Basso, Beattie, and Bresnahan (BBB) rating procedure. Lesion size and spared tissue were measured by cresyl violet staining. MicroRNA-21 (miR-21) expression was determined by real-time PCR and in situ hybridization. FasL, PDCD4, and PTEN are direct targets of miR-21 in many diseases and cell types; their levels were analyzed by western blot. Immunohistochemistry was performed to observe the expression of PDCD4 and PTEN. Cell apoptosis was assessed by TUNEL staining and DNA laddering. TMP treatment after contusion SCI significantly improved functional recovery, decreased lesion size, and increased tissue sparing and miR-21 levels; expression of FasL, PDCD4, and PTEN was decreased. TMP treatment also reduced apoptosis after SCI. Thus, TMP administration improved functional recovery and reduced cell apoptosis. Its protective effect may partly based on increasing the expression of miR-21 and decreasing the expression of FasL, PDCD4, and PTEN. These could serve as new exploratory targets for SCI treatment. PMID:27431939

  2. Maternal high-fat diet induces hyperproliferation and alters Pten/Akt signaling in prostates of offspring

    PubMed Central

    Benesh, Emily C.; Humphrey, Peter A.; Wang, Qiang; Moley, Kelle H.

    2013-01-01

    Developing recommendations for prostate cancer prevention requires identification of modifiable risk factors. Maternal exposure to high-fat diet (HFD) initiates a broad array of second-generation adult disorders in murine models and humans. Here, we investigate whether maternal HFD in mice affects incidence of prostate hyperplasia in offspring. Using three independent assays, we demonstrate that maternal HFD is sufficient to initiate prostate hyperproliferation in adult male offspring. HFD-exposed prostate tissues do not increase in size, but instead concomitantly up-regulate apoptosis. Maternal HFD-induced phenotypes are focally present in young adult subjects and greatly exacerbated in aged subjects. HFD-exposed prostate tissues additionally exhibit increased levels of activated Akt and deactivated Pten. Taken together, we conclude that maternal HFD diet is a candidate modifiable risk factor for prostate cancer initiation in later life. PMID:24322661

  3. Expression of the Androgen Receptor, pAkt, and pPTEN in Breast Cancer and Their Potential in Prognostication1

    PubMed Central

    Sultana, Aisha; Idress, Romana; Naqvi, Zulfiqar Ali; Azam, Iqbal; Khan, Shaista; Siddiqui, Anwar Ali; Lalani, El-Nasir

    2014-01-01

    BACKGROUND Importance of androgen receptor (AR) as an independent prognostic marker in Pakistani women with breast cancer (BCa) remains unexplored. Our aim was to identify the expression and potential prognostic value of AR, its upstream regulator (pAkt) and target gene (pPTEN) in invasive BCa. METHODS This study used a cohort of 200 Pakistani women with invasive BCa diagnosed during 2002-2011. Expression of AR, pAkt and pPTEN was determined on formalin fixed paraffin embedded tissue sections by immunohistochemistry. The association of AR, pAkt and pPTEN with clinicopathological parameters was determined. Survival analyses were undertaken on patients with ≥ 5 years of follow-up (n = 82). RESULTS Expression of AR, pAkt and pPTEN was observed in 47.5%, 81.3% and 50.6% of patients, respectively. AR-expressing tumors were low or intermediate in grade (P < .001) and expressed ER (P = .002) and PR (P = .001). Patients with AR+ tumors had significantly higher OS (Mean OS = 10.2 ± 0.465 years) compared to patients with AR− tumors (Mean OS = 5.8 ± 0.348 years) (P = .047). Furthermore, AR-positivity was associated with improved OS in patients receiving endocrine therapy (P = .020). Patients with AR+ /pAkt+ /pPTEN− tumors, had increased OS (Mean OS = 7.1 ± 0.535 years) compared to patients with AR−/pAkt+/pPTEN− tumors (Mean OS = 5.1 ± 0.738 years). CONCLUSION AR-expressing tumors are frequently characterized by low or intermediate grade tumors, expressing ER and PR. In addition, expression of AR, pAkt and pPTEN, could be considered in prognostication of patients with invasive BCa. PMID:24831579

  4. Increased proliferation in atypical hyperplasia/endometrioid intraepithelial neoplasia of the endometrium with concurrent inactivation of ARID1A and PTEN tumour suppressors.

    PubMed

    Ayhan, Ayse; Mao, Tsui-Lien; Suryo Rahmanto, Yohan; Zeppernick, Felix; Ogawa, Hiroshi; Wu, Ren-Chin; Wang, Tian-Li; Shih, Ie-Ming

    2015-07-01

    Uterine endometrioid carcinoma is the most common neoplastic disease in the female genital tract and develops from a common precursor lesion, atypical hyperplasia/endometrioid intraepithelial neoplasia (AH/EIN). Although the genomic landscape of endometrioid carcinoma has been recently revealed, the molecular alterations that contribute to tumour progression from AH/EIN to carcinoma remain to be elucidated. In this study, we used immunohistochemistry to determine if loss of expression of two of the most commonly mutated tumour suppressors in endometrioid carcinoma, PTEN and ARID1A, was associated with increased proliferation in AH/EIN. We found that 80 (70%) of 114 cases exhibited decreased or undetectable PTEN and 17 (15%) of 114 cases had focal loss of ARID1A staining. ARID1A loss was focal, while PTEN loss was diffuse, and all specimens with ARID1A loss had concurrent PTEN loss (p = 0.0003). Mapping the distribution of PTEN and ARID1A staining in the same specimens demonstrated that all AH/EIN areas with ARID1A loss were geographically nested within the areas of PTEN loss. A significant increase in the proliferative activity was observed in areas of AH/EIN with concurrent loss of PTEN and ARID1A compared to immediately adjacent AH/EIN areas showing only PTEN loss. In a cell culture system, co-silencing of ARID1A and PTEN in human endometrial epithelial cells increased cellular proliferation to a greater degree than silencing either ARID1A or PTEN alone. These results suggest an essential gatekeeper role for ARID1A that prevents PTEN inactivation from promoting cellular proliferation in the transition of pre-cancerous lesions to uterine endometrioid carcinoma. PMID:27499903

  5. Mir-351-5p contributes to the establishment of a pro-inflammatory environment in the H9c2 cell line by repressing PTEN expression.

    PubMed

    da Silva, Walmir; dos Santos, Robson Augusto Souza; Moraes, Karen C M

    2016-01-01

    The activated renin-angiotensin-aldosterone system modulates several metabolic pathways that contribute to left ventricular hypertrophy and heart failure. In this metabolic system, angiotensin II modulates heart morphophysiological changes triggered by a series of inflammatory and pro-inflammatory responses; however, the fine tuning associated with the control of this biochemical pathway remains unknown. Here, we investigated elements involved in the post-transcriptional regulation of the pro-inflammatory environment in the H9c2 cardiac cell line, focusing on miRNA elements that modulate PTEN expression. A cellular model of investigation was established and the miR-315-5p was identified as a novel element targeting PTEN in this cardiac cell line, thereby controlling the protein level. This interconnected pathway contributes to the control of the pro-inflammatory environment in Ang II-treated cells. PMID:26541756

  6. Tanshinone IIA inhibits apoptosis in the myocardium by inducing microRNA-152-3p expression and thereby downregulating PTEN

    PubMed Central

    Zhang, Zhen; Li, Yumei; Sheng, Chuqiao; Yang, Chunfeng; Chen, Liping; Sun, Jinghui

    2016-01-01

    Progressive loss of cardiac myocytes through apoptosis contributes to heart failure (HF). In this study, we tested whether tanshinone IIA, one of the most abundant constituents of the root of Salvia miltiorrhiza, protects rat myocardium-derived H9C2 cells against apoptosis. Treatment of H9C2 cells with tanshinone IIA inhibited angiotensin II-induced apoptosis by downregulating the expression of PTEN (phosphatase and tensin homolog), a tumor suppressor that plays a critical role in apoptosis. Furthermore, tanshinone IIA was found to inhibit PTEN expression by upregulating the microRNA miR-152-3p, a potential PTEN regulator that is highly conserved in both rat and human. Notably, the antiapoptotic effect of tanshinone IIA was partially reversed when H9C2 cells were transfected with an inhibitor of miR-152-3p. Collectively, our findings reveal a previously unrecognized mechanism underlying the cardioprotective role of tanshinone IIA, and further suggest that tanshinone IIA could represent a promising drug candidate for HF therapy. PMID:27508033

  7. Tanshinone IIA inhibits apoptosis in the myocardium by inducing microRNA-152-3p expression and thereby downregulating PTEN.

    PubMed

    Zhang, Zhen; Li, Yumei; Sheng, Chuqiao; Yang, Chunfeng; Chen, Liping; Sun, Jinghui

    2016-01-01

    Progressive loss of cardiac myocytes through apoptosis contributes to heart failure (HF). In this study, we tested whether tanshinone IIA, one of the most abundant constituents of the root of Salvia miltiorrhiza, protects rat myocardium-derived H9C2 cells against apoptosis. Treatment of H9C2 cells with tanshinone IIA inhibited angiotensin II-induced apoptosis by downregulating the expression of PTEN (phosphatase and tensin homolog), a tumor suppressor that plays a critical role in apoptosis. Furthermore, tanshinone IIA was found to inhibit PTEN expression by upregulating the microRNA miR-152-3p, a potential PTEN regulator that is highly conserved in both rat and human. Notably, the antiapoptotic effect of tanshinone IIA was partially reversed when H9C2 cells were transfected with an inhibitor of miR-152-3p. Collectively, our findings reveal a previously unrecognized mechanism underlying the cardioprotective role of tanshinone IIA, and further suggest that tanshinone IIA could represent a promising drug candidate for HF therapy. PMID:27508033

  8. PTEN regulates PLK1 and controls chromosomal stability during cell division.

    PubMed

    Zhang, Zhong; Hou, Sheng-Qi; He, Jinxue; Gu, Tingting; Yin, Yuxin; Shen, Wen H

    2016-09-16

    PTEN functions as a guardian of the genome through multiple mechanisms. We have previously established that PTEN maintains the structural integrity of chromosomes. In this report, we demonstrate a fundamental role of PTEN in controlling chromosome inheritance to prevent gross genomic alterations. Disruption of PTEN or depletion of PTEN protein phosphatase activity causes abnormal chromosome content, manifested by enlarged or polyploid nuclei. We further identify polo-like kinase 1 (PLK1) as a substrate of PTEN phosphatase. PTEN can physically associate with PLK1 and reduce PLK1 phosphorylation in a phosphatase-dependent manner. We show that PTEN deficiency leads to PLK1 phosphorylation and that a phospho-mimicking PLK1 mutant causes polyploidy, imitating functional deficiency of PTEN phosphatase. Inhibition of PLK1 activity or overexpression of a non-phosphorylatable PLK1 mutant reduces the polyploid cell population. These data reveal a new mechanism by which PTEN controls genomic stability during cell division.

  9. SLUG is a Direct Transcriptional Repressor of PTEN Tumor Suppressor

    PubMed Central

    Uygur, Berna; Abramo, Katrina; Leikina, Evgenia; Vary, Calvin; Liaw, Lucy; Wu, Wen-Shu

    2015-01-01

    BACGORUND PTEN/AKT signaling plays a key role in prostate cancer development and maintenance of prostate cancer stem cells. How other oncogenes or tumor suppressors interact with this pathway remain to be elucidated. SLUG is an zinc finger transcription factor of the Snail superfamily, and it promotes cancer metastasis and determines the mammary stem cell state. METHODS SLUG was overexpressed in cells by retroviral vector and knockdown of SLUG and PTEN was mediated by shRNAs-expressing lentiviruses. Expression level of SLUG and PTEN was examined by Western blot, RT-PCR, and qPCR analyses. PTEN promoter activity was measured by luciferase reporter assay. ChIP assay was used to measure the binding between SLUG and the PTEN promoter in vivo. RESULT We showed that overexpression of SLUG decreased expression of PTEN tumor repressor in prostate cancer cell lines 22RV1 and DU145; conversely, knockdown of SLUG expression elevated PTEN expresson at both protein and RNA level in these cells. We demonstrated that SLUG overexpression inhibits PTEN promoter activity through the proximal promoter region in prostate cancer cells. By ChIP assay, we confirmed that SLUG directly binds to the PTEN promoter region covering the E-box sites. We also showed that Slug deficiency leads to an increased expression of PTEN in mouse embryo fibroblasts and prostate tissues. Importantly, we found that overexpression of SLUG increases drug resistance of DU145 prostate cancer cell line and knockdown of SLUG by shRNA sensitizes DU145 cell line to chemotherapeutic drugs. We further demonstrated that PTEN knockdown converts drug sensitivity of DU145 cells expressing SLUG shRNA to anticancer drugs. CONCLUSION We provide compelling evidence showing that PTEN is a direct functional target of SLUG. Our findings offer new insight in the regulation of the PTEN/AKT pathway and provide a molecular basis for potential targeted therapies of prostate cancer PMID:25728608

  10. PTEN and PI-3 kinase inhibitors control LPS signaling and the lymphoproliferative response in the CD19+ B cell compartment

    SciTech Connect

    Singh, Alok R.; Peirce, Susan K.; Joshi, Shweta; Durden, Donald L.

    2014-09-10

    Pattern recognition receptors (PRRs), e.g. toll receptors (TLRs) that bind ligands within the microbiome have been implicated in the pathogenesis of cancer. LPS is a ligand for two TLR family members, TLR4 and RP105 which mediate LPS signaling in B cell proliferation and migration. Although LPS/TLR/RP105 signaling is well-studied; our understanding of the underlying molecular mechanisms controlling these PRR signaling pathways remains incomplete. Previous studies have demonstrated a role for PTEN/PI-3K signaling in B cell selection and survival, however a role for PTEN/PI-3K in TLR4/RP105/LPS signaling in the B cell compartment has not been reported. Herein, we crossed a CD19cre and PTEN{sup fl/fl} mouse to generate a conditional PTEN knockout mouse in the CD19+ B cell compartment. These mice were further crossed with an IL-14α transgenic mouse to study the combined effect of PTEN deletion, PI-3K inhibition and expression of IL-14α (a cytokine originally identified as a B cell growth factor) in CD19+ B cell lymphoproliferation and response to LPS stimulation. Targeted deletion of PTEN and directed expression of IL-14α in the CD19+ B cell compartment (IL-14+PTEN-/-) lead to marked splenomegaly and altered spleen morphology at baseline due to expansion of marginal zone B cells, a phenotype that was exaggerated by treatment with the B cell mitogen and TLR4/RP105 ligand, LPS. Moreover, LPS stimulation of CD19+ cells isolated from these mice display increased proliferation, augmented AKT and NFκB activation as well as increased expression of c-myc and cyclinD1. Interestingly, treatment of LPS treated IL-14+PTEN-/- mice with a pan PI-3K inhibitor, SF1126, reduced splenomegaly, cell proliferation, c-myc and cyclin D1 expression in the CD19+ B cell compartment and normalized the splenic histopathologic architecture. These findings provide the direct evidence that PTEN and PI-3K inhibitors control TLR4/RP105/LPS signaling in the CD19+ B cell compartment and that pan PI

  11. PTEN regulates RPA1 and protects DNA replication forks.

    PubMed

    Wang, Guangxi; Li, Yang; Wang, Pan; Liang, Hui; Cui, Ming; Zhu, Minglu; Guo, Limei; Su, Qian; Sun, Yujie; McNutt, Michael A; Yin, Yuxin

    2015-11-01

    Tumor suppressor PTEN regulates cellular activities and controls genome stability through multiple mechanisms. In this study, we report that PTEN is necessary for the protection of DNA replication forks against replication stress. We show that deletion of PTEN leads to replication fork collapse and chromosomal instability upon fork stalling following nucleotide depletion induced by hydroxyurea. PTEN is physically associated with replication protein A 1 (RPA1) via the RPA1 C-terminal domain. STORM and iPOND reveal that PTEN is localized at replication sites and promotes RPA1 accumulation on replication forks. PTEN recruits the deubiquitinase OTUB1 to mediate RPA1 deubiquitination. RPA1 deletion confers a phenotype like that observed in PTEN knockout cells with stalling of replication forks. Expression of PTEN and RPA1 shows strong correlation in colorectal cancer. Heterozygous disruption of RPA1 promotes tumorigenesis in mice. These results demonstrate that PTEN is essential for DNA replication fork protection. We propose that RPA1 is a target of PTEN function in fork protection and that PTEN maintains genome stability through regulation of DNA replication.

  12. PTEN loss is a context-dependent outcome determinant in obese and non-obese endometrioid endometrial cancer patients

    PubMed Central

    Westin, Shannon N.; Ju, Zhenlin; Broaddus, Russell R.; Krakstad, Camilla; Li, Jane; Pal, Navdeep; Lu, Karen H.; Coleman, Robert L.; Hennessy, Bryan T.; Klempner, Samuel J.; Werner, Henrica M. J.; Salvesen, Helga B.; Cantley, Lewis C.; Mills, Gordon B.; Myers, Andrea P.

    2015-01-01

    Endometrial cancer incidence is increasing, due in part to a strong association with obesity. Mutations in the phosphatidylinositol 3-kinase (PI3K) pathway, the central relay pathway of insulin signals, occur in the majority of endometrioid adenocarcinomas, the most common form of endometrial cancer. We sought to determine the impact of PI3K pathway alterations on progression free survival in a cohort of endometrioid endometrial cancers. Prognostic utility of PIK3CA, PIK3R1, and PTEN mutations, as well as PTEN protein loss by immunohistochemistry, was explored in the context of patient body mass index. Reverse-phase protein arrays were utilized to assess protein expression based on PTEN status. Among 187 endometrioid endometrial cancers, there were no statistically significant associations between PFS and PIK3CA, PIK3R1, PTEN mutation or loss. When stratified by body mass index, PTEN loss was associated with improved progression free survival (P<0.006) in obese (body mass index ≥ 30) patients. PTEN loss resulted in distinct protein changes: Canonical PI3K pathway activation was observed only in the non-obese population while decreased expression of β-CATENIN and phosphorylated FOXO3A was observed in obese patients. These data suggest the impact of PTEN loss on tumor biology and clinical outcomes must be interpreted in the context of body mass index, and provide a potential explanation for discrepant reports on the effect of PTEN status and obesity on prognosis in endometrial cancer. This reveals a clinically important interaction between metabolic state and tumor genetics that may unveil the biologic underpinning of obesity-related cancers and impact ongoing clinical trials with PI3K pathway inhibitors. PMID:26045339

  13. Endothelial Cell Surface Expressed Chemotaxis and Apoptosis Regulator (ECSCR) Regulates Lipolysis in White Adipocytes via the PTEN/AKT Signaling Pathway

    PubMed Central

    Kilari, Sreenivasulu; Cossette, Stephanie; Pooya, Shabnam; Bordas, Michelle; Huang, Yi-Wen

    2015-01-01

    Elevated plasma triglycerides are associated with increased susceptibility to heart disease and stroke, but the mechanisms behind this relationship are unclear. A clearer understanding of gene products which influence plasma triglycerides might help identify new therapeutic targets for these diseases. The Endothelial Cell Surface expressed Chemotaxis and apoptosis Regulator (ECSCR) was initially studied as an endothelial cell marker, but has recently been identified in white adipocytes, the primary storage cell type for triglycerides. Here we confirm ECSCR expression in white adipocytes and show that Ecscr knockout mice show elevated fasting plasma triglycerides. At a cellular level, cultured 3T3-L1 adipocytes silenced for Ecscr show a blunted Akt phosphorylation response. Additionally we show that the phosphatase and tensin homology containing (PTEN) lipid phosphatase association with ECSCR is increased by insulin stimulation. These data suggest a scenario by which ECSCR contributes to control of white adipocyte lipolysis. In this scenario, white adipocytes lacking Ecscr display elevated PTEN activity, thereby reducing AKT activation and impairing insulin-mediated suppression of lipolysis. Collectively, these results suggest that ECSCR plays a critical function in regulating lipolysis in white adipose tissue. PMID:26692198

  14. PTEN loss and chromosome 8 alterations in Gleason grade 3 prostate cancer cores predicts the presence of un-sampled grade 4 tumor: implications for active surveillance.

    PubMed

    Trock, Bruce J; Fedor, Helen; Gurel, Bora; Jenkins, Robert B; Knudsen, B S; Fine, Samson W; Said, Jonathan W; Carter, H Ballentine; Lotan, Tamara L; De Marzo, Angelo M

    2016-07-01

    Men who enter active surveillance because their biopsy exhibits only Gleason grade 3 (G3) frequently have higher grade tumor missed by biopsy. Thus, biomarkers are needed that, when measured on G3 tissue, can predict the presence of higher grade tumor in the whole prostate. We evaluated whether PTEN loss, chromosome 8q gain (MYC) and/or 8p loss (LPL) measured only on G3 cores is associated with un-sampled G4 tumor. A tissue microarray was constructed of prostatectomy tissue from patients whose prostates exhibited only Gleason score 3+3, only 3+4 or only 4+3 tumor (n=50 per group). Cores sampled only from areas of G3 were evaluated for PTEN loss by immunohistochemistry, and PTEN deletion, LPL/8p loss and MYC/8q gain by fluorescence in situ hybridization. Biomarker results were compared between Gleason score 6 vs 7 tumors using conditional logistic regression. PTEN protein loss, odds ratio=4.99, P=0.033; MYC/8q gain, odds ratio=5.36, P=0.010; and LPL/8p loss, odds ratio=3.96, P=0.003 were significantly more common in G3 cores derived from Gleason 7 vs Gleason 6 tumors. PTEN gene deletion was not statistically significant. Associations were stronger comparing Gleason 4+3 vs 6 than for Gleason 3+4 vs 6. MYC/8q gain, LPL/8p loss and PTEN protein loss measured in G3 tissue microarray cores strongly differentiate whether the core comes from a Gleason 6 or Gleason 7 tumor. If validated to predict upgrading from G3 biopsy to prostatectomy these biomarkers could reduce the likelihood of enrolling high-risk men and facilitate safe patient selection for active surveillance.

  15. PTEN loss and chromosome 8 alterations in Gleason grade 3 prostate cancer cores predicts the presence of un-sampled grade 4 tumor: implications for Active Surveillance

    PubMed Central

    Trock, Bruce J.; Fedor, Helen; Gurel, Bora; Jenkins, Robert B.; Knudsen, BS; Fine, Samson W.; Said, Jonathan W.; Carter, H. Ballentine; Lotan, Tamara L.; De Marzo, Angelo M.

    2016-01-01

    Men who enter active surveillance because their biopsy exhibits only Gleason grade 3 (G3) frequently have higher grade tumor missed by biopsy. Thus, biomarkers are needed that, when measured on G3 tissue, can predict the presence of higher grade tumor in the whole prostate. We evaluated whether PTEN loss, chromosome 8q gain (MYC) and/or 8p loss (LPL) measured only on G3 cores is associated with un-sampled G4 tumor. A tissue microarray was constructed of prostatectomy tissue from patients whose prostates exhibited only Gleason score 3+3, only 3+4, or only 4+3 tumor (n=50 per group). Cores sampled only from areas of G3 were evaluated for PTEN loss by immunohistochemistry, and PTEN deletion, LPL/8p loss, and MYC/8q gain by fluorescence in situ hybridization (FISH). Biomarker results were compared between Gleason score 6 vs. 7 tumors using conditional logistic regression. PTEN protein loss, odds ratio=4.99, p=.033, MYC/8q gain, odds ratio=5.36, p=.010, and LPL/8p loss, odds ratio=3.96, p=.003 were significantly more common in G3 cores derived from Gleason 7 vs. Gleason 6 tumors. PTEN gene deletion was not statistically significant. Associations were stronger comparing Gleason 4+3 vs. 6 than for Gleason 3+4 vs. 6. MYC/8q gain, LPL/8p loss, and PTEN protein loss measured in G3 tissue microarray cores strongly differentiate whether the core comes from a Gleason 6 or Gleason 7 tumor. If validated to predict upgrading from G3 biopsy to prostatectomy these biomarkers could reduce the likelihood of enrolling high risk men and facilitate safe patient selection for active surveillance. PMID:27080984

  16. DNMT1-mediated PTEN hypermethylation confers hepatic stellate cell activation and liver fibrogenesis in rats

    SciTech Connect

    Bian, Er-Bao; Huang, Cheng; Ma, Tao-Tao; Tao, Hui; Zhang, Hui; Cheng, Chang; Lv, Xiong-Wen; Li, Jun

    2012-10-01

    Hepatic stellate cell (HSC) activation is an essential event during liver fibrogenesis. Phosphatase and tension homolog deleted on chromosome 10 (PTEN), a tumor suppressor, is a negative regulator of this process. PTEN promoter hypermethylation is a major epigenetic silencing mechanism in tumors. The present study aimed to investigate whether PTEN promoter methylation was involved in HSC activation and liver fibrosis. Treatment of activated HSCs with the DNA methylation inhibitor 5-aza-2′-deoxycytidine (5-azadC) decreased aberrant hypermethylation of the PTEN gene promoter and prevented the loss of PTEN expression that occurred during HSC activation. Silencing DNA methyltransferase 1 (DNMT1) gene also decreased the PTEN gene promoter methylation and upregulated the PTEN gene expression in activated HSC-T6 cells. In addition, knockdown of DNMT1 inhibited the activation of both ERK and AKT pathways in HSC-T6 cells. These results suggest that DNMT1-mediated PTEN hypermethylation caused the loss of PTEN expression, followed by the activation of the PI3K/AKT and ERK pathways, resulting in HSC activation. Highlights: ► PTEN methylation status and loss of PTEN expression ► DNMT1 mediated PTEN hypermethylation. ► Hypermethylation of PTEN contributes to the activation of ERK and AKT pathways.

  17. Activation of Toll-like receptor 7 regulates the expression of IFN-λ1, p53, PTEN, VEGF, TIMP-1 and MMP-9 in pancreatic cancer cells.

    PubMed

    Wang, Fang; Jin, Rui; Zou, Bing-Bing; Li, Lei; Cheng, Feng-Wei; Luo, Xin; Geng, Xiaoping; Zhang, Sheng-Quan

    2016-02-01

    Toll-like receptors (TLRs) are critical in the induction of the immune response in tumor development. TLR7 has previously been demonstrated to be associated with the development of pancreatic cancer, and the release of cytokines and chemokines from other types of cancer cell; however, the specific expression induced by TLR7 agonists in pancreatic cancer cells remains to be elucidated. The present study aimed to investigate the effects of the TLR7 agonist, gardiquimod, on ERK1/2 signaling pathway, and on the expression of genes involved in the pathogenesis of cancer, including phosphatase and tensin homolog deleted on chromosome 10 (PTEN), p53, type Ⅲ interferon (IFN-λ1), vascular endothelial growth factor (VEGF), matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1). The results demonstrated that activation of TLR7 upregulated the expression levels of certain genes to varying degrees; the expression levels of IFN-λ1 and MMP-9 were increased by ~3 fold, whereas other genes (p53, PTEN, TIMP-1) were upregulated by ~2 fold, and VEGF was marginally upregulated after 10 min. Furthermore, gardiquimod increased the expression levels of phosphorylated-extracellular signal-regulated kinase (ERK)1/2. In addition, PD98059, a specific inhibitor of ERK phosphorylation, inhibited the ability of gardiquimod to activate ERK1/2; consequently weakening the effect of gardiquimod on gene regulation. These findings indicated that the effect of TLR7 agonists, including gardiquimod, on gene expression in BxPC-3 pancreatic cancer cells was partly associated with the mitogen-activated protein kinase-ERK1/2 signaling pathway.

  18. Oocyte-specific deletion of Pten in mice reveals a stage-specific function of PTEN/PI3K signaling in oocytes in controlling follicular activation.

    PubMed

    Jagarlamudi, Krishna; Liu, Lian; Adhikari, Deepak; Reddy, Pradeep; Idahl, Annika; Ottander, Ulrika; Lundin, Eva; Liu, Kui

    2009-07-09

    Immature ovarian primordial follicles are essential for maintenance of the reproductive lifespan of female mammals. Recently, it was found that overactivation of the phosphatidylinositol 3-kinase (PI3K) signaling in oocytes of primordial follicles by an oocyte-specific deletion of Pten (phosphatase and tensin homolog deleted on chromosome ten), the gene encoding PI3K negative regulator PTEN, results in premature activation of the entire pool of primordial follicles, indicating that activation of the PI3K pathway in oocytes is important for control of follicular activation. To investigate whether PI3K signaling in oocytes of primary and further developed follicles also plays a role at later stages in follicular development and ovulation, we conditionally deleted the Pten gene from oocytes of primary and further developed follicles by using transgenic mice expressing zona pellucida 3 (Zp3) promoter-mediated Cre recombinase. Our results show that Pten was efficiently deleted from oocytes of primary and further developed follicles, as indicated by the elevated phosphorylation of the major PI3K downstream component Akt. However, follicular development was not altered and oocyte maturation was also normal, which led to normal fertility with unaltered litter size in the mutant mice. Our data indicate that properly controlled PTEN/PI3K-Akt signaling in oocytes is essential for control of the development of primordial follicles whereas overactivation of PI3K signaling in oocytes does not appear to affect the development of growing follicles. This suggests that there is a stage-specific function of PTEN/PI3K signaling in mouse oocytes that controls follicular activation.

  19. Pten Regulates Epithelial Cytodifferentiation during Prostate Development

    PubMed Central

    Lokody, Isabel B.; Francis, Jeffrey C.; Gardiner, Jennifer R.; Erler, Janine T.; Swain, Amanda

    2015-01-01

    Gene expression and functional studies have indicated that the molecular programmes involved in prostate development are also active in prostate cancer. PTEN has been implicated in human prostate cancer and is frequently mutated in this disease. Here, using the Nkx3.1:Cre mouse strain and a genetic deletion approach, we investigate the role of Pten specifically in the developing mouse prostate epithelia. In contrast to its role in other developing organs, this gene is dispensable for the initial developmental processes such as budding and branching. However, as cytodifferentiation progresses, abnormal luminal cells fill the ductal lumens together with augmented epithelial proliferation. This phenotype resembles the hyperplasia seen in postnatal Pten deletion models that develop neoplasia at later stages. Consistent with this, gene expression analysis showed a number of genes affected that are shared with Pten mutant prostate cancer models, including a decrease in androgen receptor regulated genes. In depth analysis of the phenotype of these mice during development revealed that loss of Pten leads to the precocious differentiation of epithelial cells towards a luminal cell fate. This study provides novel insight into the role of Pten in prostate development as part of the process of coordinating the differentiation and proliferation of cell types in time and space to form a functional organ. PMID:26076167

  20. Loss of Mel-18 induces tumor angiogenesis through enhancing the activity and expression of HIF-1α mediated by the PTEN/PI3K/Akt pathway.

    PubMed

    Park, J H; Lee, J Y; Shin, D H; Jang, K S; Kim, H J; Kong, Gu

    2011-11-10

    Mel-18 has been implicated in several processes in tumor progression, in which the Akt pathway is involved as an important key molecular event. However, the function of Mel-18 in human cancers has not been fully established yet. Here, we examined the effect of Mel-18 on tumor angiogenesis in human breast cancer, and found that Mel-18 was a novel regulator of HIF-1α. Mel-18 negatively regulated the HIF-1α expression and its target gene VEGF transcription during both normoxia and hypoxia. We demonstrated that Mel-18 regulated the HIF-1α expression and activity via the PI3K/Akt pathway. Loss of Mel-18 downregulated Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) expression, consequently activating the PI3K/Akt/MDM2 pathway, and leading to an increase of HIF-1α protein level. Mel-18 modulated the HIF-1α transcriptional activity via regulating the cytoplasmic retention of FOXO3a, a downstream effector of Akt, and recruitment of HIF-1α/CBP complex to the VEGF promoter. Furthermore, our data shows that Mel-18 blocked tumor angiogenesis both in vitro and in vivo. Mel-18 overexpression inhibited in vitro tube formation in human umbilical endothelial cells (HUVECs). Xenografts in NOD/SCID mice derived from stably Mel-18 knocked down MCF7 human breast cancer cells showed increased tumor volume, microvessel density, and phospho-Akt and HIF-1α expression levels. In conclusion, our findings provide that Mel-18 is a novel regulator of tumor angiogenesis through regulating HIF-1α and its target VEGF expressions mediated by the PTEN/PI3K/Akt pathway, suggesting a new tumor-suppressive role of Mel-18 in human breast cancer.

  1. C-Myc negatively controls the tumor suppressor PTEN by upregulating miR-26a in glioblastoma multiforme cells

    SciTech Connect

    Guo, Pin; Nie, Quanmin; Lan, Jin; Ge, Jianwei; Qiu, Yongming; Mao, Qing

    2013-11-08

    Highlights: •The c-Myc oncogene directly upregulates miR-26a expression in GBM cells. •ChIP assays demonstrate that c-Myc interacts with the miR-26a promoter. •Luciferase reporter assays show that PTEN is a specific target of miR-26a. •C-Myc–miR-26a suppression of PTEN may regulate the PTEN/AKT pathway. •Overexpression of c-Myc enhances the proliferative capacity of GBM cells. -- Abstract: The c-Myc oncogene is amplified in many tumor types. It is an important regulator of cell proliferation and has been linked to altered miRNA expression, suggesting that c-Myc-regulated miRNAs might contribute to tumor progression. Although miR-26a has been reported to be upregulated in glioblastoma multiforme (GBM), the mechanism has not been established. We have shown that ectopic expression of miR-26a influenced cell proliferation by targeting PTEN, a tumor suppressor gene that is inactivated in many common malignancies, including GBM. Our findings suggest that c-Myc modulates genes associated with oncogenesis in GBM through deregulation of miRNAs via the c-Myc–miR-26a–PTEN signaling pathway. This may be of clinical relevance.

  2. PNUTS functions as a proto-oncogene by sequestering PTEN.

    PubMed

    Kavela, Sridhar; Shinde, Swapnil R; Ratheesh, Raman; Viswakalyan, Kotapalli; Bashyam, Murali D; Gowrishankar, Swarnalata; Vamsy, Mohana; Pattnaik, Sujit; Rao, Subramanyeshwar; Sastry, Regulagadda A; Srinivasulu, Mukta; Chen, Junjie; Maddika, Subbareddy

    2013-01-01

    PTEN is a well-defined tumor suppressor gene that antagonizes the PI3K/Akt pathway to regulate a multitude of cellular processes, such as survival, growth, motility, invasiveness, and angiogenesis. While the functions of PTEN have been studied extensively, the regulation of its activity during normal and disease conditions still remains incompletely understood. In this study, we identified the protein phosphatase-1 nuclear targeting subunit PNUTS (PPP1R10) as a PTEN-associated protein. PNUTS directly interacted with the lipid-binding domain (C2 domain) of PTEN and sequestered it in the nucleus. Depletion of PNUTS leads to increased apoptosis and reduced cellular proliferation in a PTEN-dependent manner. PNUTS expression was elevated in certain cancers compared with matched normal tissues. Collectively, our studies reveal PNUTS as a novel PTEN regulator and a likely oncogene.

  3. PNUTS functions as a proto-oncogene by sequestering PTEN

    PubMed Central

    Kavela, Sridhar; Shinde, Swapnil R; Ratheesh, Raman; Viswakalyan, Kotapalli; Bashyam, Murali D; Gowrishankar, Swarnalata; Vamsy, Mohana; Pattnaik, Sujit; Rao, Subramanyeshwar; Sastry, Regulagadda A; Srinivasulu, Mukta; Chen, Junjie; Maddika, Subbareddy

    2012-01-01

    PTEN is a well-defined tumor suppressor gene that antagonizes the PI3K/Akt pathway to regulate a multitude of cellular processes such as survival, growth, motility, invasiveness and angiogenesis. While the functions of PTEN have been studied extensively, the regulation of its activity during normal and disease conditions still remains incompletely understood. In this study, we identified the protein phosphatase-1 nuclear targeting subunit PNUTS (PPP1R10) as a PTEN associated protein. PNUTS directly interacted with the lipid-binding domain (C2 domain) of PTEN and sequestered it in the nucleus. Depletion of PNUTS leads to increased apoptosis and reduced cellular proliferation in a PTEN-dependent manner. PNUTS expression was elevated in certain cancers compared to matched normal tissues. Collectively, our studies reveal PNUTS as a novel PTEN regulator and a likely oncogene. PMID:23117887

  4. Systemic elevation of PTEN induces a tumor suppressive metabolic state

    PubMed Central

    Garcia-Cao, Isabel; Song, Min Sup; Hobbs, Robin M.; Laurent, Gaelle; Giorgi, Carlotta; de Boer, Vincent C.J.; Anastasiou, Dimitrios; Ito, Keisuke; Sasaki, Atsuo T.; Rameh, Lucia; Carracedo, Arkaitz; Vander Heiden, Matthew G.; Cantley, Lewis C.; Pinton, Paolo; Haigis, Marcia C.; Pandolfi, Pier Paolo

    2012-01-01

    SUMMARY Decremental loss of PTEN results in cancer susceptibility and tumor progression. In turn this raises the possibility that PTEN elevation might be an attractive option for cancer prevention and therapy. We have generated several transgenic mouse lines with variably elevated PTEN expression levels, taking advantage of BAC (Bacterial Artificial Chromosome)-mediated transgenesis. Super-PTEN mutants are viable and show reduced body size due to decreased cell number, with no effect on cell size. Unexpectedly, PTEN elevation at the organism level results in healthy metabolism characterized by increased energy expenditure and reduced body fat accumulation. Cells derived from these mice show reduced glucose and glutamine uptake, increased mitochondrial oxidative phosphorylation, and are resistant to oncogenic transformation. Mechanistically we find that PTEN elevation orchestrates this metabolic switch by regulating PI3K-dependent and independent pathways, and negatively impacts two of the most pronounced metabolic features of tumor cells: glutaminolysis and the Warburg effect. PMID:22401813

  5. MicroRNA-21 expression and its pathogenetic significance in cutaneous melanoma.

    PubMed

    Saldanha, Gerald; Potter, Linda; Lee, Yee Shin; Watson, Sophie; Shendge, Priya; Pringle, James H

    2016-02-01

    Identification of prognostic biomarkers is timely for melanoma as clinicians seek ways to stratify patients for molecular therapy. MicroRNAs are promising as tissue biomarkers because they can be assayed directly from formalin-fixed paraffin-embedded clinical samples. We previously reported that microRNA-21 (miR-21) was strongly expressed in melanoma relative to naevi and now sought to further assess the significance of this by assessing its relationship with its putative target, PTEN. Clinical melanoma samples were analysed by immunohistochemical analysis for PTEN, stem-loop qRT-PCR for miR-21 and PCR for BRAF/NRAS mutation status. Cell lines were investigated for the effect of anti-miR-21 on PTEN. A total of 81 clinical melanocytic tumour samples were investigated, with uniformly high PTEN expression in the nucleus and cytoplasm of naevi and with preferential loss of PTEN expression in the nucleus of melanoma cells. miR-21 expression was inversely associated with nuclear PTEN expression but not with cytoplasmic PTEN expression. An anti-miR-21 preferentially altered nuclear PTEN in melanoma cell lines. The presence of a BRAF or NRAS mutation had no significant effect on miR-21 expression. These data suggest miR-21 may exert an oncogenic effect in melanoma by favouring redistribution of PTEN to the nucleus.

  6. PTEN and NEDD4 in Human Breast Carcinoma.

    PubMed

    Chen, Yilun; van de Vijver, Marc J; Hibshoosh, Hanina; Parsons, Ramon; Saal, Lao H

    2016-01-01

    PTEN is an important tumor suppressor gene that antagonizes the oncogenic PI3K/AKT signaling pathway and has functions in the nucleus for maintaining genome integrity. Although PTEN inactivation by mutation is infrequent in breast cancer, transcript and protein levels are deficient in >25 % of cases. The E3 ubiquitin ligase NEDD4 (also known as NEDD4-1) has been reported to negatively regulate PTEN protein levels through poly-ubiquitination and proteolysis in carcinomas of the prostate, lung, and bladder, but its effect on PTEN in the breast has not been studied extensively. To investigate whether NEDD4 contributes to low PTEN levels in human breast cancer, we analyzed the expression of these proteins by immunohistochemistry across a large Swedish cohort of breast tumor specimens, and their transcript expression levels by microarrays. For both NEDD4 and PTEN, their transcript expression was significantly correlated to their protein expression. However, comparing NEDD4 expression to PTEN expression, either no association or a positive correlation was observed at the protein and transcript levels. This unexpected observation was further corroborated in two independent breast cancer cohorts from The Netherlands Cancer Institute and The Cancer Genome Atlas. Our results suggest that NEDD4 is not responsible for the frequent down-regulation of the PTEN protein in human breast carcinoma.

  7. Fine-Tuning of Pten Localization and Phosphatase Activity Is Essential for Zebrafish Angiogenesis.

    PubMed

    Stumpf, Miriam; Blokzijl-Franke, Sasja; den Hertog, Jeroen

    2016-01-01

    The lipid- and protein phosphatase PTEN is an essential tumor suppressor that is highly conserved among all higher eukaryotes. As an antagonist of the PI3K/Akt cell survival and proliferation pathway, it exerts its most prominent function at the cell membrane, but (PIP3-independent) functions of nuclear PTEN have been discovered as well. PTEN subcellular localization is tightly controlled by its protein conformation. In the closed conformation, PTEN localizes predominantly to the cytoplasm. Opening up of the conformation of PTEN exposes N-terminal and C-terminal regions of the protein that are required for both interaction with the cell membrane and translocation to the nucleus. Lack of Pten leads to hyperbranching of the intersegmental vessels during zebrafish embryogenesis, which is rescued by expression of exogenous Pten. Here, we observed that expression of mutant PTEN with an open conformation rescued the hyperbranching phenotype in pten double homozygous embryos and suppressed the increased p-Akt levels that are characteristic for embryos lacking Pten. In addition, in pten mutant and wild type embryos alike, open conformation PTEN induced stalled intersegmental vessels, which fail to connect with the dorsal longitudinal anastomotic vessel. Functional hyperactivity of open conformation PTEN in comparison to wild type PTEN seems to result predominantly from its enhanced recruitment to the cell membrane. Enhanced recruitment of phosphatase inactive mutants to the membrane did not induce the stalled vessel phenotype nor did it rescue the hyperbranching phenotype in pten double homozygous embryos, indicating that PTEN phosphatase activity is indispensable for its regulatory function during angiogenesis. Taken together, our data suggest that PTEN phosphatase activity needs to be carefully fine-tuned for normal embryogenesis and that the control of its subcellular localization is a key mechanism in this process. PMID:27138341

  8. Fine-Tuning of Pten Localization and Phosphatase Activity Is Essential for Zebrafish Angiogenesis

    PubMed Central

    Stumpf, Miriam; Blokzijl-Franke, Sasja; den Hertog, Jeroen

    2016-01-01

    The lipid- and protein phosphatase PTEN is an essential tumor suppressor that is highly conserved among all higher eukaryotes. As an antagonist of the PI3K/Akt cell survival and proliferation pathway, it exerts its most prominent function at the cell membrane, but (PIP3-independent) functions of nuclear PTEN have been discovered as well. PTEN subcellular localization is tightly controlled by its protein conformation. In the closed conformation, PTEN localizes predominantly to the cytoplasm. Opening up of the conformation of PTEN exposes N-terminal and C-terminal regions of the protein that are required for both interaction with the cell membrane and translocation to the nucleus. Lack of Pten leads to hyperbranching of the intersegmental vessels during zebrafish embryogenesis, which is rescued by expression of exogenous Pten. Here, we observed that expression of mutant PTEN with an open conformation rescued the hyperbranching phenotype in pten double homozygous embryos and suppressed the increased p-Akt levels that are characteristic for embryos lacking Pten. In addition, in pten mutant and wild type embryos alike, open conformation PTEN induced stalled intersegmental vessels, which fail to connect with the dorsal longitudinal anastomotic vessel. Functional hyperactivity of open conformation PTEN in comparison to wild type PTEN seems to result predominantly from its enhanced recruitment to the cell membrane. Enhanced recruitment of phosphatase inactive mutants to the membrane did not induce the stalled vessel phenotype nor did it rescue the hyperbranching phenotype in pten double homozygous embryos, indicating that PTEN phosphatase activity is indispensable for its regulatory function during angiogenesis. Taken together, our data suggest that PTEN phosphatase activity needs to be carefully fine-tuned for normal embryogenesis and that the control of its subcellular localization is a key mechanism in this process. PMID:27138341

  9. Microgravity alters the expression of salivary proteins.

    PubMed

    Mednieks, Maija; Khatri, Aditi; Rubenstein, Renee; Burleson, Joseph A; Hand, Arthur R

    2014-06-01

    Spaceflight provides a unique opportunity to study how physiologic responses are influenced by the external environment. Microgravity has been shown to alter the function of a number of tissues and organ systems. Very little, however, is known about how microgravity affects the oral cavity. The rodent model is useful for study in that their salivary gland morphology and physiology is similar to that of humans. Useful also is the fact that saliva, a product of the salivary glands with a major role in maintaining oral health, can be easily collected in humans whereas the glands can be studied in experimental animals. Our working hypothesis is that expression of secretory proteins in saliva will respond to microgravity and will be indicative of the nature of physiologic reactions to travel in space. This study was designed to determine which components of the salivary proteome are altered in mice flown on the US space shuttle missions and to determine if a subset with predictive value can be identified using microscopy and biochemistry methods. The results showed that the expression of secretory proteins associated with beta-adrenergic hormone regulated responses and mediated via the cyclic AMP pathway was significantly altered, whereas that of a number of unrelated proteins was not. The findings are potentially applicable to designing a biochemical test system whereby specific salivary proteins can be biomarkers for stress associated with travel in space and eventually for monitoring responses to conditions on earth.

  10. Microgravity alters the expression of salivary proteins.

    PubMed

    Mednieks, Maija; Khatri, Aditi; Rubenstein, Renee; Burleson, Joseph A; Hand, Arthur R

    2014-06-01

    Spaceflight provides a unique opportunity to study how physiologic responses are influenced by the external environment. Microgravity has been shown to alter the function of a number of tissues and organ systems. Very little, however, is known about how microgravity affects the oral cavity. The rodent model is useful for study in that their salivary gland morphology and physiology is similar to that of humans. Useful also is the fact that saliva, a product of the salivary glands with a major role in maintaining oral health, can be easily collected in humans whereas the glands can be studied in experimental animals. Our working hypothesis is that expression of secretory proteins in saliva will respond to microgravity and will be indicative of the nature of physiologic reactions to travel in space. This study was designed to determine which components of the salivary proteome are altered in mice flown on the US space shuttle missions and to determine if a subset with predictive value can be identified using microscopy and biochemistry methods. The results showed that the expression of secretory proteins associated with beta-adrenergic hormone regulated responses and mediated via the cyclic AMP pathway was significantly altered, whereas that of a number of unrelated proteins was not. The findings are potentially applicable to designing a biochemical test system whereby specific salivary proteins can be biomarkers for stress associated with travel in space and eventually for monitoring responses to conditions on earth. PMID:24984624

  11. Activating PTEN by COX-2 inhibitors antagonizes radiation-induced AKT activation contributing to radiosensitization

    SciTech Connect

    Meng, Zhen; Gan, Ye-Hua

    2015-05-01

    Radiotherapy is still one of the most effective nonsurgical treatments for many tumors. However, radioresistance remains a major impediment to radiotherapy. Although COX-2 inhibitors can induce radiosensitization, the underlying mechanism is not fully understood. In this study, we showed that COX-2 selective inhibitor celecoxib enhanced the radiation-induced inhibition of cell proliferation and apoptosis in HeLa and SACC-83 cells. Treatment with celecoxib alone dephosphorylated phosphatase and tensin homolog deleted on chromosome ten (PTEN), promoted PTEN membrane translocation or activation, and correspondingly dephosphorylated or inactivated protein kinase B (AKT). By contrast, treatment with radiation alone increased PTEN phosphorylation, inhibited PTEN membrane translocation and correspondingly activated AKT in the two cell lines. However, treatment with celecoxib or another COX-2 selective inhibitor (valdecoxib) completely blocked radiation-induced increase of PTEN phosphorylation, rescued radiation-induced decrease in PTEN membrane translocation, and correspondingly inactivated AKT. Moreover, celecoxib could also upregulate PTEN protein expression by downregulating Sp1 expression, thereby leading to the activation of PTEN transcription. Our results suggested that COX-2 inhibitors could enhance radiosensitization at least partially by activating PTEN to antagonize radiation-induced AKT activation. - Highlights: • COX-2 inhibitor, celecoxib, could enhance radiosensitization. • Radiation induced PTEN inactivation (phosphorylation) and AKT activation. • COX-2 inhibitor induced PTEN expression and activation, and inactivated AKT. • COX-2 inhibitor enhanced radiosensitization through activating PTEN.

  12. Altered CD45 expression and disease.

    PubMed

    Tchilian, Elma Z; Beverley, Peter C L

    2006-03-01

    CD45, the leucocyte common antigen, is a haemopoietic cell-specific tyrosine phosphatase. Many isoforms are generated by alternative splicing, but their function remains obscure. The extracellular domain of CD45 is highly polymorphic in all vertebrates. Importantly, human polymorphic variants that alter CD45 isoform expression are associated with autoimmune and infectious diseases, establishing CD45 as an important immunomodulator with a significant influence on disease burden. Here, we discuss the new opportunities provided by the human variants for investigating and understanding how CD45 regulates antigen receptor signalling, cytokine responses and apoptosis. PMID:16423560

  13. L1-CAM knock-down radiosensitizes neuroblastoma IMR-32 cells by simultaneously decreasing MycN, but increasing PTEN protein expression.

    PubMed

    Rached, Johnny; Nasr, Zeina; Abdallah, Jad; Abou-Antoun, Tamara

    2016-10-01

    Childhood neuroblastoma is one of the most malignant types of cancers leading to a high mortality rate. These cancerous cells can be highly metastatic and malignant giving rise to disease recurrence and poor prognosis. The proto-oncogene myelocytomatosis neuroblastoma (MycN) is known to be amplified in this type of cancer, thus, promoting high malignancy and resistance. The L1 cell adhesion molecule (L1-CAM) cleavage has been found upregulated in many types of malignant cancers. In the present study, we explored the interplay between L1-CAM, MycN and PTEN as well as the role played by PDGFR and VEGFR on tumorigenicity in neuroblastoma cells. We investigated the effect of L1-CAM knock-down (KD) and PDGFR/VEGFR inhibition with sunitinib malate (Sutent®) treatment on subsequent tumorsphere formation and cellular proliferation and migration in the MycN-amplified IMR-32 neuroblastoma cells. We further examined the effect of combined L1-CAM KD with Sutent treatment or radiotherapy on these cellular functions in our cells. Tumorsphere formation is one of the indicators of aggressiveness in malignant cancers, which was significantly inhibited in IMR-32 cells after L1-CAM KD or Sutent treatment, however, no synergistic effect was observed with dual treatments, rather L1-CAM KD alone showed a greater inhibition on tumorsphere formation compared to Sutent treatment alone. In addition, cellular proliferation and migration were significantly inhibited after L1-CAM KD in the IMR-32 cells with no synergistic effect observed on the rate of cell proliferation when combined with Sutent treatment. Again, L1-CAM KD alone exhibited greater inhibitory effect than Sutent treatment on cell proliferation. L1-CAM KD led to the simultaneous downregulation of MycN, but the upregulation of PTEN protein expression. Notably, radiotherapy (2 Gy) of the IMR-32 cells led to significant upregulation of both L1-CAM and MycN, which was abrogated with L1-CAM KD in our cells. In addition, L1-CAM KD

  14. L1-CAM knock-down radiosensitizes neuroblastoma IMR-32 cells by simultaneously decreasing MycN, but increasing PTEN protein expression.

    PubMed

    Rached, Johnny; Nasr, Zeina; Abdallah, Jad; Abou-Antoun, Tamara

    2016-10-01

    Childhood neuroblastoma is one of the most malignant types of cancers leading to a high mortality rate. These cancerous cells can be highly metastatic and malignant giving rise to disease recurrence and poor prognosis. The proto-oncogene myelocytomatosis neuroblastoma (MycN) is known to be amplified in this type of cancer, thus, promoting high malignancy and resistance. The L1 cell adhesion molecule (L1-CAM) cleavage has been found upregulated in many types of malignant cancers. In the present study, we explored the interplay between L1-CAM, MycN and PTEN as well as the role played by PDGFR and VEGFR on tumorigenicity in neuroblastoma cells. We investigated the effect of L1-CAM knock-down (KD) and PDGFR/VEGFR inhibition with sunitinib malate (Sutent®) treatment on subsequent tumorsphere formation and cellular proliferation and migration in the MycN-amplified IMR-32 neuroblastoma cells. We further examined the effect of combined L1-CAM KD with Sutent treatment or radiotherapy on these cellular functions in our cells. Tumorsphere formation is one of the indicators of aggressiveness in malignant cancers, which was significantly inhibited in IMR-32 cells after L1-CAM KD or Sutent treatment, however, no synergistic effect was observed with dual treatments, rather L1-CAM KD alone showed a greater inhibition on tumorsphere formation compared to Sutent treatment alone. In addition, cellular proliferation and migration were significantly inhibited after L1-CAM KD in the IMR-32 cells with no synergistic effect observed on the rate of cell proliferation when combined with Sutent treatment. Again, L1-CAM KD alone exhibited greater inhibitory effect than Sutent treatment on cell proliferation. L1-CAM KD led to the simultaneous downregulation of MycN, but the upregulation of PTEN protein expression. Notably, radiotherapy (2 Gy) of the IMR-32 cells led to significant upregulation of both L1-CAM and MycN, which was abrogated with L1-CAM KD in our cells. In addition, L1-CAM KD

  15. Hematopoietic Stem Cell Activity Is Regulated by Pten Phosphorylation Through a Niche-Dependent Mechanism.

    PubMed

    Li, Jing; Zhang, Jun; Tang, Minghui; Xin, Junping; Xu, Yan; Volk, Andrew; Hao, Caiqin; Hu, Chenglong; Sun, Jiewen; Wei, Wei; Cao, Quichan; Breslin, Peter; Zhang, Jiwang

    2016-08-01

    The phosphorylated form of Pten (p-Pten) is highly expressed in >70% of acute myeloid leukemia samples. However, the role of p-Pten in normal and abnormal hematopoiesis has not been studied. We found that Pten protein levels are comparable among long-term (LT) hematopoietic stem cells (HSCs), short-term (ST) HSCs, and multipotent progenitors (MPPs); however, the levels of p-Pten are elevated during the HSC-to-MPP transition. To study whether p-Pten is involved in regulating self-renewal and differentiation in HSCs, we compared the effects of overexpression of p-Pten and nonphosphorylated Pten (non-p-Pten) on the hematopoietic reconstitutive capacity (HRC) of HSCs. We found that overexpression of non-p-Pten enhances the LT-HRC of HSCs, whereas overexpression of p-Pten promotes myeloid differentiation and compromises the LT-HRC of HSCs. Such phosphorylation-regulated Pten functioning is mediated by repressing the cell:cell contact-induced activation of Fak/p38 signaling independent of Pten's lipid phosphatase activity because both p-Pten and non-p-Pten have comparable activity in repressing PI3K/Akt signaling. Our studies suggest that, in addition to repressing PI3K/Akt/mTor signaling, non-p-Pten maintains HSCs in bone marrow niches via a cell-contact inhibitory mechanism by inhibiting Fak/p38 signaling-mediated proliferation and differentiation. In contrast, p-Pten promotes the proliferation and differentiation of HSCs by enhancing the cell contact-dependent activation of Src/Fak/p38 signaling. Stem Cells 2016;34:2130-2144.

  16. Hematopoietic Stem Cell Activity Is Regulated by Pten Phosphorylation Through a Niche-Dependent Mechanism.

    PubMed

    Li, Jing; Zhang, Jun; Tang, Minghui; Xin, Junping; Xu, Yan; Volk, Andrew; Hao, Caiqin; Hu, Chenglong; Sun, Jiewen; Wei, Wei; Cao, Quichan; Breslin, Peter; Zhang, Jiwang

    2016-08-01

    The phosphorylated form of Pten (p-Pten) is highly expressed in >70% of acute myeloid leukemia samples. However, the role of p-Pten in normal and abnormal hematopoiesis has not been studied. We found that Pten protein levels are comparable among long-term (LT) hematopoietic stem cells (HSCs), short-term (ST) HSCs, and multipotent progenitors (MPPs); however, the levels of p-Pten are elevated during the HSC-to-MPP transition. To study whether p-Pten is involved in regulating self-renewal and differentiation in HSCs, we compared the effects of overexpression of p-Pten and nonphosphorylated Pten (non-p-Pten) on the hematopoietic reconstitutive capacity (HRC) of HSCs. We found that overexpression of non-p-Pten enhances the LT-HRC of HSCs, whereas overexpression of p-Pten promotes myeloid differentiation and compromises the LT-HRC of HSCs. Such phosphorylation-regulated Pten functioning is mediated by repressing the cell:cell contact-induced activation of Fak/p38 signaling independent of Pten's lipid phosphatase activity because both p-Pten and non-p-Pten have comparable activity in repressing PI3K/Akt signaling. Our studies suggest that, in addition to repressing PI3K/Akt/mTor signaling, non-p-Pten maintains HSCs in bone marrow niches via a cell-contact inhibitory mechanism by inhibiting Fak/p38 signaling-mediated proliferation and differentiation. In contrast, p-Pten promotes the proliferation and differentiation of HSCs by enhancing the cell contact-dependent activation of Src/Fak/p38 signaling. Stem Cells 2016;34:2130-2144. PMID:27096933

  17. Klf5 Deletion Promotes Pten Deletion–Initiated Luminal-Type Mouse Prostate Tumors through Multiple Oncogenic Signaling Pathways12

    PubMed Central

    Xing, Changsheng; Ci, Xinpei; Sun, Xiaodong; Fu, Xiaoying; Zhang, Zhiqian; Dong, Eric N.; Hao, Zhao-Zhe; Dong, Jin-Tang

    2014-01-01

    Krüppel-like factor 5 (KLF5) regulates multiple biologic processes. Its function in tumorigenesis appears contradictory though, showing both tumor suppressor and tumor promoting activities. In this study, we examined whether and how Klf5 functions in prostatic tumorigenesis using mice with prostate-specific deletion of Klf5 and phosphatase and tensin homolog (Pten), both of which are frequently inactivated in human prostate cancer. Histologic analysis demonstrated that when one Pten allele was deleted, which causes mouse prostatic intraepithelial neoplasia (mPIN), Klf5 deletion accelerated the emergence and progression of mPIN. When both Pten alleles were deleted, which causes prostate cancer, Klf5 deletion promoted tumor growth, increased cell proliferation, and caused more severe morphologic and molecular alterations. Homozygous deletion of Klf5 was more effective than hemizygous deletion. Unexpectedly, while Pten deletion alone expanded basal cell population in a tumor as reported, Klf5 deletion in the Pten-null background clearly reduced basal cell population while expanding luminal cell population. Global gene expression profiling, pathway analysis, and experimental validation indicate that multiple mechanisms could mediate the tumor-promoting effect of Klf5 deletion, including the up-regulation of epidermal growth factor and its downstream signaling molecules AKT and ERK and the inactivation of the p15 cell cycle inhibitor. KLF5 also appears to cooperate with several transcription factors, including CREB1, Sp1, Myc, ER and AR, to regulate gene expression. These findings validate the tumor suppressor function of KLF5. They also yield a mouse model that shares two common genetic alterations with human prostate cancer—mutation/deletion of Pten and deletion of Klf5. PMID:25425963

  18. The PTEN tumor suppressor gene and its role in lymphoma pathogenesis

    PubMed Central

    Wang, Xiaoxiao; Huang, Huiqiang; Young, Ken H.

    2015-01-01

    The phosphatase and tensin homolog gene PTEN is one of the most frequently mutated tumor suppressor genes in human cancer. Loss of PTEN function occurs in a variety of human cancers via its mutation, deletion, transcriptional silencing, or protein instability. PTEN deficiency in cancer has been associated with advanced disease, chemotherapy resistance, and poor survival. Impaired PTEN function, which antagonizes phosphoinositide 3-kinase (PI3K) signaling, causes the accumulation of phosphatidylinositol (3,4,5)-triphosphate and thereby the suppression of downstream components of the PI3K pathway, including the protein kinase B and mammalian target of rapamycin kinases. In addition to having lipid phosphorylation activity, PTEN has critical roles in the regulation of genomic instability, DNA repair, stem cell self-renewal, cellular senescence, and cell migration. Although PTEN deficiency in solid tumors has been studied extensively, rare studies have investigated PTEN alteration in lymphoid malignancies. However, genomic or epigenomic aberrations of PTEN and dysregulated signaling are likely critical in lymphoma pathogenesis and progression. This review provides updated summary on the role of PTEN deficiency in human cancers, specifically in lymphoid malignancies; the molecular mechanisms of PTEN regulation; and the distinct functions of nuclear PTEN. Therapeutic strategies for rescuing PTEN deficiency in human cancers are proposed. PMID:26655726

  19. Shadows Alter Facial Expressions of Noh Masks

    PubMed Central

    Kawai, Nobuyuki; Miyata, Hiromitsu; Nishimura, Ritsuko; Okanoya, Kazuo

    2013-01-01

    Background A Noh mask, worn by expert actors during performance on the Japanese traditional Noh drama, conveys various emotional expressions despite its fixed physical properties. How does the mask change its expressions? Shadows change subtly during the actual Noh drama, which plays a key role in creating elusive artistic enchantment. We here describe evidence from two experiments regarding how attached shadows of the Noh masks influence the observers’ recognition of the emotional expressions. Methodology/Principal Findings In Experiment 1, neutral-faced Noh masks having the attached shadows of the happy/sad masks were recognized as bearing happy/sad expressions, respectively. This was true for all four types of masks each of which represented a character differing in sex and age, even though the original characteristics of the masks also greatly influenced the evaluation of emotions. Experiment 2 further revealed that frontal Noh mask images having shadows of upward/downward tilted masks were evaluated as sad/happy, respectively. This was consistent with outcomes from preceding studies using actually tilted Noh mask images. Conclusions/Significance Results from the two experiments concur that purely manipulating attached shadows of the different types of Noh masks significantly alters the emotion recognition. These findings go in line with the mysterious facial expressions observed in Western paintings, such as the elusive qualities of Mona Lisa’s smile. They also agree with the aesthetic principle of Japanese traditional art “yugen (profound grace and subtlety)”, which highly appreciates subtle emotional expressions in the darkness. PMID:23940748

  20. TBX2 represses PTEN in rhabdomyosarcoma and skeletal muscle

    PubMed Central

    Zhu, Bo; Zhang, Meiling; Williams, Elizabeth M.; Keller, Charles; Mansoor, Atiya; Davie, Judith K.

    2015-01-01

    Rhabdomyosarcoma (RMS) is the most frequent soft tissue sarcoma in children that shares many features of developing skeletal muscle. TBX2, a T-box family member, is highly up regulated in tumor cells of both major RMS subtypes where it functions as an oncogene. TBX2 is a repressor that is often over expressed in cancer cells and functions in bypassing cell growth control, including the repression of the cell cycle regulators p14 and p21. We have found that TBX2 directly represses the tumor suppressor PTEN in both RMS and normal muscle. Exogenous expression of TBX2 in normal muscle cells down regulates PTEN, and depletion or interference with TBX2 in RMS cells up regulates PTEN. Human RMS tumors show high levels of TBX2 and correspondingly low levels of PTEN. The expression of PTEN in clinical RMS samples is relatively uncharacterized and we establish that suppression of PTEN is a frequent event in both subtypes of RMS. TBX2 represses PTEN by directly binding to the promoter and recruiting the histone deacetylase, HDAC1. RMS cells have high levels of activated AKT due to the deregulation of PI3K signaling, and depletion or interference with TBX2, which up regulates PTEN, results in a reduction of phospho-AKT. We have also found that the highly related T-box family member TBX3 does not repress PTEN in the muscle lineage. This work suggests that TBX2 is a central component of the PTEN/PI3K/AKT signaling pathway deregulation in RMS cells and that targeting TBX2 in RMS tumors may offer a novel therapeutic approach for RMS. PMID:26686089

  1. Mechanisms underlying PTEN regulation of vascular endothelial growth factor and angiogenesis.

    PubMed

    Gomez-Manzano, Candelaria; Fueyo, Juan; Jiang, Hong; Glass, Tricia L; Lee, Ho-Young; Hu, Min; Liu, Juinn-Lin; Jasti, Sushma L; Liu, Ta-Jen; Conrad, Charles A; Yung, W K Alfred

    2003-01-01

    Inactivation of the tumor suppressor gene PTEN and overexpression of VEGF are two of the most common events observed in high-grade malignant gliomas. The purpose of this study was to determine whether PTEN controls VEGF expression in gliomas under normoxic conditions. Transfer of PTEN to human glioma cells resulted in the transduction of a functional PTEN protein as evidenced by the upregulation of p27 and modification of the phosphorylation status of Akt. Under normoxic conditions, enzyme-linked immunosorbent assay and Northern blot analyses showed downregulation of VEGF in PTEN-treated cells. Moreover, conditioned media from PTEN-treated glioma cells significantly diminished the ability of endothelial cells to grow and migrate. Western blot assays demonstrated that, in a normoxic environment, PTEN downregulates HIF-1 alpha. Finally, promoter activity assays showed that the VEGF promoter region containing the HIF-1alpha binding site is necessary and sufficient for PTEN-mediated downregulation of VEGF. Experiments with PI3-K inhibitors and kinase assays suggested that PI3-K is mediating the effect of PTEN on VEGF, and not the p42/p48 or p38 MAP kinases. These results indicate that restoration of PTEN function in gliomas may induce therapeutic effect by downregulating VEGF. Furthermore, this close functional relationship between PTEN and VEGF suggests that a better understanding of the transduction signal regulated by PTEN might enhance the knowledge of the cause and physiology of vascular and inflammatory diseases.

  2. A pseudogene long noncoding RNA network regulates PTEN transcription and translation in human cells

    PubMed Central

    Johnsson, Per; Ackley, Amanda; Vidarsdottir, Linda; Lui, Weng-Onn; Corcoran, Martin; Grandér, Dan; Morris, Kevin V.

    2013-01-01

    PTEN is a tumor suppressor gene that has been shown to be under the regulatory control of a PTEN pseudogene expressed noncoding RNA, PTENpg1. Here, we characterize a previously unidentified PTENpg1 encoded antisense RNA (asRNA), which regulates PTEN transcription and PTEN mRNA stability. We find two PTENpg1 asRNA isoforms, alpha and beta. The alpha isoform functions in trans, localizes to the PTEN promoter, and epigenetically modulates PTEN transcription by the recruitment of DNMT3a and EZH2. In contrast, the beta isoform interacts with PTENpg1 through an RNA:RNA pairing interaction, which affects PTEN protein output via changes of PTENpg1 stability and microRNA sponge activity. Disruption of this asRNA-regulated network induces cell cycle arrest and sensitizes cells to doxorubicin, suggesting a biological function for the respective PTENpg1 expressed asRNAs. PMID:23435381

  3. Imbalanced PTEN and PI3K Signaling Impairs Class Switch Recombination.

    PubMed

    Chen, Zhangguo; Getahun, Andrew; Chen, Xiaomi; Dollin, Yonatan; Cambier, John C; Wang, Jing H

    2015-12-01

    Class switch recombination (CSR) generates isotype-switched Abs with distinct effector functions. B cells express phosphatase and tensin homolog (PTEN) and multiple isoforms of class IA PI3K catalytic subunits, including p110α and p110δ, whose roles in CSR remain unknown or controversial. In this article, we demonstrate a direct effect of PTEN on CSR signaling by acute deletion of Pten specifically in mature B cells, thereby excluding the developmental impact of Pten deletion. We show that mature B cell-specific PTEN overexpression enhances CSR. More importantly, we establish a critical role for p110α in CSR. Furthermore, we identify a cooperative role for p110α and p110δ in suppressing CSR. Mechanistically, dysregulation of p110α or PTEN inversely affects activation-induced deaminase expression via modulating AKT activity. Thus, our study reveals that a signaling balance between PTEN and PI3K isoforms is essential to maintain normal CSR.

  4. TBX2 represses PTEN in rhabdomyosarcoma and skeletal muscle.

    PubMed

    Zhu, B; Zhang, M; Williams, E M; Keller, C; Mansoor, A; Davie, J K

    2016-08-11

    Rhabdomyosarcoma (RMS) is the most frequent soft tissue sarcoma in children that shares many features of developing skeletal muscle. TBX2, a T-box family member, is highly upregulated in tumor cells of both major RMS subtypes where it functions as an oncogene. TBX2 is a repressor that is often overexpressed in cancer cells and functions in bypassing cell growth control, including the repression of the cell cycle regulators p14 and p21. We have found that TBX2 directly represses the tumor-suppressor phosphatase and tensin homolog (PTEN) in both RMS and normal muscle. Exogenous expression of TBX2 in normal muscle cells downregulates PTEN, and depletion or interference with TBX2 in RMS cells upregulates PTEN. Human RMS tumors show high levels of TBX2 and correspondingly low levels of PTEN. The expression of PTEN in clinical RMS samples is relatively uncharacterized, and we establish that suppression of PTEN is a frequent event in both subtypes of RMS. TBX2 represses PTEN by directly binding to the promoter and recruiting the histone deacetylase, HDAC1. RMS cells have high levels of activated AKT owing to the deregulation of phosphoinositide-3 kinase (PI3K) signaling, and depletion or interference with TBX2, which upregulates PTEN, results in a reduction of phospho-AKT. We have also found that the highly related T-box family member TBX3 does not repress PTEN in the muscle lineage. This work suggests that TBX2 is a central component of the PTEN/PI3K/AKT signaling pathway deregulation in RMS cells and that targeting TBX2 in RMS tumors may offer a novel therapeutic approach for RMS.

  5. Epstein–Barr virus-encoded microRNA BART1 induces tumour metastasis by regulating PTEN-dependent pathways in nasopharyngeal carcinoma

    PubMed Central

    Cai, Longmei; Ye, Yanfen; Jiang, Qiang; Chen, Yuxiang; Lyu, Xiaoming; Li, Jinbang; Wang, Shuang; Liu, Tengfei; Cai, Hongbing; Yao, Kaitai; Li, Ji-Liang; Li, Xin

    2015-01-01

    Epstein–Barr virus (EBV), aetiologically linked to nasopharyngeal carcinoma (NPC), is the first human virus found to encode many miRNAs. However, how these viral miRNAs precisely regulate the tumour metastasis in NPC remains obscure. Here we report that EBV-miR-BART1 is highly expressed in NPC and closely associated with pathological and advanced clinical stages of NPC. Alteration of EBV-miR-BART1 expression results in an increase in migration and invasion of NPC cells in vitro and causes tumour metastasis in vivo. Mechanistically, EBV-miR-BART1 directly targets the cellular tumour suppressor PTEN. Reduction of PTEN dosage by EBV-miR-BART1 activates PTEN-dependent pathways including PI3K-Akt, FAK-p130Cas and Shc-MAPK/ERK1/2 signalling, drives EMT, and consequently increases migration, invasion and metastasis of NPC cells. Reconstitution of PTEN rescues all phenotypes generated by EBV-miR-BART1, highlighting the role of PTEN in EBV-miR-BART-driven metastasis in NPC. Our findings provide new insights into the metastasis of NPC regulated by EBV and advocate for developing clinical intervention strategies against NPC. PMID:26135619

  6. Epstein-Barr virus-encoded microRNA BART1 induces tumour metastasis by regulating PTEN-dependent pathways in nasopharyngeal carcinoma.

    PubMed

    Cai, Longmei; Ye, Yanfen; Jiang, Qiang; Chen, Yuxiang; Lyu, Xiaoming; Li, Jinbang; Wang, Shuang; Liu, Tengfei; Cai, Hongbing; Yao, Kaitai; Li, Ji-Liang; Li, Xin

    2015-01-01

    Epstein-Barr virus (EBV), aetiologically linked to nasopharyngeal carcinoma (NPC), is the first human virus found to encode many miRNAs. However, how these viral miRNAs precisely regulate the tumour metastasis in NPC remains obscure. Here we report that EBV-miR-BART1 is highly expressed in NPC and closely associated with pathological and advanced clinical stages of NPC. Alteration of EBV-miR-BART1 expression results in an increase in migration and invasion of NPC cells in vitro and causes tumour metastasis in vivo. Mechanistically, EBV-miR-BART1 directly targets the cellular tumour suppressor PTEN. Reduction of PTEN dosage by EBV-miR-BART1 activates PTEN-dependent pathways including PI3K-Akt, FAK-p130(Cas) and Shc-MAPK/ERK1/2 signalling, drives EMT, and consequently increases migration, invasion and metastasis of NPC cells. Reconstitution of PTEN rescues all phenotypes generated by EBV-miR-BART1, highlighting the role of PTEN in EBV-miR-BART-driven metastasis in NPC. Our findings provide new insights into the metastasis of NPC regulated by EBV and advocate for developing clinical intervention strategies against NPC. PMID:26135619

  7. FOXO1/3 and PTEN Depletion in Granulosa Cells Promotes Ovarian Granulosa Cell Tumor Development.

    PubMed

    Liu, Zhilin; Ren, Yi A; Pangas, Stephanie A; Adams, Jaye; Zhou, Wei; Castrillon, Diego H; Wilhelm, Dagmar; Richards, JoAnne S

    2015-07-01

    The forkhead box (FOX), FOXO1 and FOXO3, transcription factors regulate multiple functions in mammalian cells. Selective inactivation of the Foxo1 and Foxo3 genes in murine ovarian granulosa cells severely impairs follicular development and apoptosis causing infertility, and as shown here, granulosa cell tumor (GCT) formation. Coordinate depletion of the tumor suppressor Pten gene in the Foxo1/3 strain enhanced the penetrance and onset of GCT formation. Immunostaining and Western blot analyses confirmed FOXO1 and phosphatase and tensin homolog (PTEN) depletion, maintenance of globin transcription factor (GATA) 4 and nuclear localization of FOXL2 and phosphorylated small mothers against decapentaplegic (SMAD) 2/3 in the tumor cells, recapitulating results we observed in human adult GCTs. Microarray and quantitative PCR analyses of mouse GCTs further confirmed expression of specific genes (Foxl2, Gata4, and Wnt4) controlling granulosa cell fate specification and proliferation, whereas others (Emx2, Nr0b1, Rspo1, and Wt1) were suppressed. Key genes (Amh, Bmp2, and Fshr) controlling follicle growth, apoptosis, and differentiation were also suppressed. Inhbb and Grem1 were selectively elevated, whereas reduction of Inha provided additional evidence that activin signaling and small mothers against decapentaplegic (SMAD) 2/3 phosphorylation impact GCT formation. Unexpectedly, markers of Sertoli/epithelial cells (SRY [sex determining region Y]-box 9/keratin 8) and alternatively activated macrophages (chitinase 3-like 3) were elevated in discrete subpopulations within the mouse GCTs, indicating that Foxo1/3/Pten depletion not only leads to GCTs but also to altered granulosa cell fate decisions and immune responses. Thus, analyses of the Foxo1/3/Pten mouse GCTs and human adult GCTs provide strong evidence that impaired functions of the FOXO1/3/PTEN pathways lead to dramatic changes in the molecular program within granulosa cells, chronic activin signaling in the presence of

  8. PTEN overexpression attenuates angiogenic processes of endothelial cells by blockade of endothelin-1/endothelin B receptor signaling.

    PubMed

    Kuo, Hsiao-Mei; Lin, Chun-Yao; Lam, Hing-Chung; Lin, Pey-Ru; Chan, Hoi-Hung; Tseng, Jui-Cheng; Sun, Cheuk-Kwan; Hsu, Te-Fa; Wu, Chia-Ching; Yang, Chao-Yuh; Hsu, Ching-Mei; Tai, Ming-Hong

    2012-04-01

    Arteriovenous (AV) graft is frequently used as vascular access in hemodialysis patients. However, clotting or thrombosis of AV grafts often occurs and requires surgical removal. At present, the molecular pathogenesis underlying thrombosis of AV graft is not clear. The PTEN/Akt signaling has been implicated in the pathogenesis of vascular diseases. In this study, elevated PTEN expression and concomitant Akt inactivation was observed in endothelium of atherosclerotic brachial arteries from hemodialysis patients. To investigate whether PTEN upregulation affects endothelial function, adenovirus-mediated PTEN (Ad-PTEN) overexpression was performed in aorta rings and cultured endothelial cells. It was found that PTEN overexpression potently inhibited the microvessel sprouting in aorta rings and the angiogenic activities of endothelial cells including migration and tube formation. On the contrary, PTEN knockdown by RNA interference promoted the endothelial migration and reversed the Ad-PTEN-induced inhibition of endothelial migration. Expression analysis showed that PTEN overexpression attenuated the expression of endothelin-1 (ET-1) and endothelin B receptor (ETBR) in endothelial cells at transcriptional levels. However, exogenous ET-1 supply only partially reversed the PTEN-induced inhibition of migration and tube formation. This was delineated due to that PTEN overexpression also perturbed endothelial nitric oxide synthase (eNOS) activation and vascular endothelial growth factor (VEGF) release. In summary, PTEN upregulation induces endothelial dysfunction by attenuating the availability and signaling of multiple angiogenic pathways in endothelial cells, thereby may contribute to thrombosis of AV graft.

  9. Defective PTEN regulation contributes to B cell hyperresponsiveness in systemic lupus erythematosus.

    PubMed

    Wu, Xiang-ni; Ye, Yan-xia; Niu, Jing-wen; Li, Yang; Li, Xin; You, Xin; Chen, Hua; Zhao, Li-dan; Zeng, Xiao-feng; Zhang, Feng-chun; Tang, Fu-lin; He, Wei; Cao, Xue-tao; Zhang, Xuan; Lipsky, Peter E

    2014-07-23

    PTEN regulates normal signaling through the B cell receptor (BCR). In systemic lupus erythematosus (SLE), enhanced BCR signaling contributes to increased B cell activity, but the role of PTEN in human SLE has remained unclear. We performed fluorescence-activated cell sorting analysis in B cells from SLE patients and found that all SLE B cell subsets, except for memory B cells, showed decreased expression of PTEN compared with B cells from healthy controls. Moreover, the level of PTEN expression was inversely correlated with disease activity. We then explored the mechanisms governing PTEN regulation in SLE B cells. Notably, in normal but not SLE B cells, interleukin-21 (IL-21) induced PTEN expression and suppressed Akt phosphorylation induced by anti-immunoglobulin M and CD40L stimulation. However, this deficit was not primarily at the signaling or the transcriptional level, because IL-21-induced STAT3 (signal transducer and activator of transcription 3) phosphorylation was intact and IL-21 up-regulated PTEN mRNA in SLE B cells. Therefore, we examined the expression of candidate microRNAs (miRs) that could regulate PTEN: SLE B cells were found to express increased levels of miR-7, miR-21, and miR-22. These miRs down-regulated the expression of PTEN, and IL-21 stimulation increased the expression of miR-7 and miR-22 in both normal and SLE B cells. Indeed, a miR-7 antagomir corrected PTEN-related abnormalities in SLE B cells in a manner dependent on PTEN. Therefore, defective miR-7 regulation of PTEN contributes to B cell hyperresponsiveness in SLE and could be a new target of therapeutic intervention.

  10. Analysis of PTEN ubiquitylation and SUMOylation using molecular traps.

    PubMed

    Lang, Valérie; Aillet, Fabienne; Da Silva-Ferrada, Elisa; Xolalpa, Wendy; Zabaleta, Lorea; Rivas, Carmen; Rodriguez, Manuel S

    2015-05-01

    The function of the tumour suppressor phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is tightly controlled by post-translational modifications (PTMs) including ubiquitin or Small Ubiquitin-related MOdifiers (SUMO). It is known that SUMOylation by SUMO-1, SUMO-2/-3, mono- or polyubiquitylation have a distinct impact on PTEN activity, localisation and/or stability, however the molecular mechanisms governing these processes are still unclear. Studying PTM regulated events has always been a difficult task due to their labile nature. Here, we propose an update on the role of these PTMs on PTEN function, as well as a methodological overview on the use of molecular traps named SUMO Binding Entities (SUBEs) or Tandem Ubiquitin Binding Entities (TUBEs) to capture SUMOylated or Ubiquitylated forms of PTEN respectively. When combined with in vitro SUMOylation or Ubiquitylation assays, the use of molecular traps facilitate the detection of modified forms of PTEN. SUMO and ubiquitin-traps are also suitable to capture endogenously modified forms of PTEN after expression of E3 ligases or treatment with chemical inhibitors. This versatile approach represents an interesting alternative to explore PTEN regulation by SUMO and ubiquitin under physiological or pathological conditions.

  11. Endothelial cells promote neural stem cell proliferation and differentiation associated with VEGF activated Notch and Pten signaling.

    PubMed

    Sun, Jinqiao; Zhou, Wenhao; Ma, Duan; Yang, Yi

    2010-09-01

    To investigate whether and how endothelial cells affect neurogenesis, we established a system to co-culture endothelial cells and brain slices of neonatal rat and observed how subventricular zone cells differentiate in the presence of endothelial cells. In the presence of endothelial cells, neural stem cells increased in number, as did differentiated neurons and glia. The augmentation of neurogenesis was reversed by diminishing vascular endothelial growth factor (VEGF) expression in endothelial cells with RNA interference (RNAi). Microarray analysis indicated that expression levels of 112 genes were significantly altered by co-culture and that expression of 81 of the 112 genes recovered to normal levels following RNAi of VEGF in endothelial cells. Pathway mapping showed an enrichment of genes in the Notch and Pten pathways. These data indicate that endothelial cells promote neural stem cell proliferation and differentiation associated with VEGF, possibly by activating the Notch and Pten pathways.

  12. PTEN is involved in modulation of vasculogenesis in early chick embryos.

    PubMed

    Li, Yan; Wang, Xiao-Yu; Wu, Ting; Chuai, Manli; Lee, Kenneth Ka Ho; Wang, Li-Jing; Yang, Xuesong

    2013-06-15

    PTEN is a tumor suppressor gene that is mutated and/or deleted in many types of tumor. This gene also plays a very distinct role in the early stages of embryonic development such as cell migration, proliferation and migration. Nevertheless, little is known of the function of PTEN in vasculogenesis during chick embryonic development. In this study, we used in situ hybridization to first demonstrate the expression pattern of PTEN during gastrulation. PTEN was found mainly expressed in the blood islands of area opaca, the neural tube and mesodermal structures. Overexpression of PTEN obstructed the epithelial-mesenchymal transition (EMT) process in the primitive streak. EMT is the first prerequisite required for the emigration of hemangioblasts during vasculogenesis. When PTEN expression was silenced, we observed that it produced an adverse effect on mesodermal cell emigration to the extra-embryonic blood islands. In addition, we also demonstrated that even if the perturbed-PTEN cells did not affect the formation of blood islands, migrant mesodermal cells overexpressing wt PTEN-GFP had difficulties integrating into the blood islands. Instead, these cells were either localized on the periphery of the blood islands or induced to differentiate into endothelial cells if they managed to integrate into blood islands. Development of the intra-embryonic primary vascular plexus was also affected by overexpression of PTEN. We proposed that it was elevated PTEN lipid phosphatase activity that was responsible for the morphogenetic defects induced by PTEN overexpression. In this context, we did not find PTEN affecting VEGF signaling. In sum, our study has provided evidence that PTEN is involved in vasculogenesis during the early stages of chick embryo development.

  13. PTEN induces apoptosis and cavitation via HIF-2-dependent Bnip3 upregulation during epithelial lumen formation

    PubMed Central

    Qi, Y; Liu, J; Saadat, S; Tian, X; Han, Y; Fong, G-H; Pandolfi, P P; Lee, L Y; Li, S

    2015-01-01

    The tumor suppressor phosphatase and tensin homolog (PTEN) dephosphorylates PIP3 and antagonizes the prosurvival PI3K-Akt pathway. Targeted deletion of PTEN in mice led to early embryonic lethality. To elucidate its role in embryonic epithelial morphogenesis and the underlying mechanisms, we used embryonic stem cell-derived embryoid body (EB), an epithelial cyst structurally similar to the periimplantation embryo. PTEN is upregulated during EB morphogenesis in parallel with apoptosis of core cells, which mediates EB cavitation. Genetic ablation of PTEN causes Akt overactivation, apoptosis resistance and cavitation blockade. However, rescue experiments using mutant PTEN and pharmacological inhibition of Akt suggest that the phosphatase activity of PTEN and Akt are not involved in apoptosis-mediated cavitation. Instead, hypoxia-induced upregulation of Bnip3, a proapoptotic BH3-only protein, mediates PTEN-dependent apoptosis and cavitation. PTEN inactivation inhibits hypoxia- and reactive oxygen species-induced Bnip3 elevation. Overexpression of Bnip3 in PTEN-null EBs rescues apoptosis of the core cells. Mechanistically, suppression of Bnip3 following PTEN loss is likely due to reduction of hypoxia-inducible factor-2α (HIF-2α) because forced expression of an oxygen-stable HIF-2α mutant rescues Bnip3 expression and apoptosis. Lastly, we show that HIF-2α is upregulated by PTEN at both transcriptional and posttranscriptional levels. Ablation of prolyl hydroxylase domain-containing protein 2 (PHD2) in normal EBs or inhibition of PHD activities in PTEN-null EBs stabilizes HIF-2α and induces Bnip3 and caspase-3 activation. Altogether, these results suggest that PTEN is required for apoptosis-mediated cavitation during epithelial morphogenesis by regulating the expression of HIF-2α and Bnip3. PMID:25394489

  14. Association of PTEN mutation with HPV-negative adenocarcinoma of the uterine cervix.

    PubMed

    Minaguchi, Takeo; Yoshikawa, Hiroyuki; Nakagawa, Shunsuke; Yasugi, Toshiharu; Yano, Tetsu; Iwase, Haruko; Mizutani, Katsumi; Shiromizu, Kenji; Ohmi, Kazuo; Watanabe, Yoh; Noda, Kiichiro; Nishiu, Mieko; Nakamura, Yusuke; Taketani, Yuji

    2004-07-01

    Serous, mucinous, endometrioid, and clear cell adenocarcinomas arise from reproductive organs of mullerian origin. Although the mutation of PTEN, a tumor suppressor, is known to be involved in tumorigenesis of endometrioid adenocarcinomas of the endometrium and ovary, the role of PTEN alteration in endometrioid adenocarcinoma of the cervix remains to be investigated. To elucidate the molecular pathogenesis of cervical adenocarcinoma and adenosquamous carcinoma, and in particular to examine the potential role of PTEN mutation in endometrioid-type cancer of the cervix, we analyzed 32 cervical adeno- or adenosquamous carcinomas (8 endometrioid adenocarcinomas, 14 mucinous adenocarcinomas and 10 adenosquamous carcinomas) for PTEN mutations and HPV infections. PTEN mutation was detected in 2 of 8 (25.0%) endometrioid cases, 2 of 14 (14.3%) mucinous cases, and none of 10 (0%) adenosquamous cases. HPV DNA was detected in 11 out of 18 (61.1%) PTEN wild-type adenocarcinomas and 8 out of 10 (80.0%) adenosquamous carcinomas. Among 11 HPV-negative adenocarcinomas, 40.0% (2/5) endometrioid cases and 33.3% (2/6) mucinous cases were shown to be PTEN mutated, while no cases (0/21) were PTEN-mutant in the remainder (i.e. adenosquamous carcinomas and HPV-positive adenocarcinomas). The current observations suggest that PTEN mutation is frequently detected in HPV-negative adenocarcinomas of the cervix and the most prevalent occurrence of PTEN mutation in endometrioid subtype is keeping with endometrial and ovarian carcinomas.

  15. Identification of PTEN mutations in metastatic melanoma specimens

    PubMed Central

    Celebi, J. T.; Shendrik, I.; Silvers, D.; Peacocke, M.

    2000-01-01

    CONTEXT—PTEN, a tumour suppressor gene located on chromosome 10q23, develops somatic mutations in various tumours and tumour cell lines including brain, endometrium, prostate, breast, kidney, thyroid, liver, and melanoma.
OBJECTIVES—To investigate the mutational profile of this gene further, as well as its role in tumour progression in melanoma.
DESIGN, SETTINGS—We examined 21 metastatic melanoma samples for 10q23 allelic losses and PTEN sequence alterations. Additionally, we screened these samples for mutations in CDKN2A, a gene in which alterations are well documented in primary melanoma as well as in the germline of familial melanoma.
RESULTS—Loss of heterozygosity (LOH) at 10q23 was observed in 33% (7/21) of the samples tested. We identified four sequence alterations in PTEN (19%) and two in CDKN2A (9.5%). Of interest, only one case showed mutations in both genes.
CONCLUSIONS—These data support the notion that PTEN alterations occur in some metastatic melanomas, and that mutation of this gene plays a role in the progression of some forms of melanoma.


Keywords: PTEN; CDKN2A; melanoma PMID:10978354

  16. RNA interference mediated pten knock-down inhibit the formation of polycystic ovary.

    PubMed

    Ouyang, Jie-Xiu; Luo, Tao; Sun, Hui-Yun; Huang, Jian; Tang, Dan-Feng; Wu, Lei; Zheng, Yue-Hui; Zheng, Li-Ping

    2013-08-01

    Pten (phosphatase and tensin homolog deleted on chromosome 10), a kind of tumor suppressor gene, plays important roles in female reproductive system. But its expression and roles in the formation of polycystic ovaries are yet to be known. In this study, we constructed a rat model of PCOS using norethindrone and HCG injections and found the expressions of pten mRNA and PTEN protein increased significantly in the polycystic ovary tissue by immunohistochemistry, RT-PCR, and western blot. Furthermore, the results showed that in vivo ovaries could be effectively transfected by lentiviral vectors through the ovarian microinjection method and indicated that pten shRNA may inhibit the formation of polycystic ovaries by pten down-regulation. Our study provides new information regarding the role of PTEN in female reproductive disorders, such as polycystic ovary syndrome.

  17. PTEN regulates cilia through Dishevelled

    PubMed Central

    Shnitsar, Iryna; Bashkurov, Mikhail; Masson, Glenn R.; Ogunjimi, Abiodun A.; Mosessian, Sherly; Cabeza, Eduardo Aguiar; Hirsch, Calley L.; Trcka, Daniel; Gish, Gerald; Jiao, Jing; Wu, Hong; Winklbauer, Rudolf; Williams, Roger L.; Pelletier, Laurence; Wrana, Jeffrey L.; Barrios-Rodiles, Miriam

    2015-01-01

    Cilia are hair-like cellular protrusions important in many aspects of eukaryotic biology. For instance, motile cilia enable fluid movement over epithelial surfaces, while primary (sensory) cilia play roles in cellular signalling. The molecular events underlying cilia dynamics, and particularly their disassembly, are not well understood. Phosphatase and tensin homologue (PTEN) is an extensively studied tumour suppressor, thought to primarily act by antagonizing PI3-kinase signalling. Here we demonstrate that PTEN plays an important role in multicilia formation and cilia disassembly by controlling the phosphorylation of Dishevelled (DVL), another ciliogenesis regulator. DVL is a central component of WNT signalling that plays a role during convergent extension movements, which we show here are also regulated by PTEN. Our studies identify a novel protein substrate for PTEN that couples PTEN to regulation of cilia dynamics and WNT signalling, thus advancing our understanding of potential underlying molecular etiologies of PTEN-related pathologies. PMID:26399523

  18. PTEN Contributes to Profound PI3K/Akt Signaling Pathway Deregulation in Dystrophin-Deficient Dog Muscle

    PubMed Central

    Feron, Marie; Guevel, Laetitia; Rouger, Karl; Dubreil, Laurence; Arnaud, Marie-Claire; Ledevin, Mireille; Megeney, Lynn A.; Cherel, Yan; Sakanyan, Vehary

    2009-01-01

    Duchenne muscular dystrophy is the most common and severe form of muscular dystrophy, and although the genetic basis of this disease is well defined, the overall mechanisms that define its pathogenesis remain obscure. Alterations in individual signaling pathways have been described, but little information is available regarding their putative implications in Duchenne muscular dystrophy pathogenesis. Here, we studied the status of various major signaling pathways in the Golden Retriever muscular dystrophy dog that specifically reproduces the full spectrum of human pathology. Using antibody arrays, we found that Akt1, glycogen synthase kinase-3β (GSK3β), 70-kDa ribosomal protein S6 kinase (p70S6K), extracellular signal-regulated kinases 1/2, and p38δ and p38γ kinases all exhibited decreased phosphorylation in muscle from a 4-month-old animal with Golden Retriever muscular dystrophy, revealing a deep alteration of the phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen-activated protein kinase pathways. Immunohistochemistry analysis revealed the presence of muscle fibers exhibiting a cytosolic accumulation of Akt1, GSK3β, and phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase (PTEN), an enzyme counteracting PI3K-mediated Akt activation. Enzymatic assays established that these alterations in phosphorylation and expression levels were associated with decreased Akt and increased GSK3β and PTEN activities. PTEN/GSK3β-positive fibers were also observed in muscle sections from 3- and 36-month-old animals, indicating long-term PI3K/Akt pathway alteration. Collectively, our data suggest that increased PTEN expression and activity play a central role in PI3K/Akt/GSK3β and p70S6K pathway modulation, which could exacerbate the consequences of dystrophin deficiency. PMID:19264909

  19. Adenovirus mediated homozygous endometrial epithelial Pten deletion results in aggressive endometrial carcinoma

    SciTech Connect

    Joshi, Ayesha; Ellenson, Lora Hedrick

    2011-07-01

    Pten is the most frequently mutated gene in uterine endometriod carcinoma (UEC) and its precursor complex atypical hyperplasia (CAH). Because the mutation frequency is similar in CAH and UEC, Pten mutations are thought to occur relatively early in endometrial tumorigenesis. Previous work from our laboratory using the Pten{sup +/-} mouse model has demonstrated somatic inactivation of the wild type allele of Pten in both CAH and UEC. In the present study, we injected adenoviruses expressing Cre into the uterine lumen of adult Pten floxed mice in an attempt to somatically delete both alleles of Pten specifically in the endometrium. Our results demonstrate that biallelic inactivation of Pten results in an increased incidence of carcinoma as compared to the Pten{sup +/-} mouse model. In addition, the carcinomas were more aggressive with extension beyond the uterus into adjacent tissues and were associated with decreased expression of nuclear ER{alpha} as compared to associated CAH. Primary cultures of epithelial and stromal cells were prepared from uteri of Pten floxed mice and Pten was deleted in vitro using Cre expressing adenovirus. Pten deletion was evident in both the epithelial and stromal cells and the treatment of the primary cultures with estrogen had different effects on Akt activation as well as Cyclin D3 expression in the two purified components. This study demonstrates that somatic biallelic inactivation of Pten in endometrial epithelium in vivo results in an increased incidence and aggressiveness of endometrial carcinoma compared to mice carrying a germline deletion of one allele and provides an important in vivo and in vitro model system for understanding the genetic underpinnings of endometrial carcinoma.

  20. Selective deletion of Pten in pancreatic beta cells leads to increased islet mass and resistance to STZ-induced diabetes.

    PubMed

    Stiles, Bangyan L; Kuralwalla-Martinez, Christine; Guo, Wei; Gregorian, Caroline; Wang, Ying; Tian, Jide; Magnuson, Mark A; Wu, Hong

    2006-04-01

    Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a lipid phosphatase. PTEN inhibits the action of phosphatidylinositol-3-kinase and reduces the levels of phosphatidylinositol triphosphate, a crucial second messenger for cell proliferation and survival, as well as insulin signaling. In this study, we deleted Pten specifically in the insulin producing beta cells during murine pancreatic development. Pten deletion leads to increased cell proliferation and decreased cell death, without significant alteration of beta-cell differentiation. Consequently, the mutant pancreas generates more and larger islets, with a significant increase in total beta-cell mass. PTEN loss also protects animals from developing streptozotocin-induced diabetes. Our data demonstrate that PTEN loss in beta cells is not tumorigenic but beneficial. This suggests that modulating the PTEN-controlled signaling pathway is a potential approach for beta-cell protection and regeneration therapies. PMID:16537919

  1. Selective deletion of Pten in pancreatic beta cells leads to increased islet mass and resistance to STZ-induced diabetes.

    PubMed

    Stiles, Bangyan L; Kuralwalla-Martinez, Christine; Guo, Wei; Gregorian, Caroline; Wang, Ying; Tian, Jide; Magnuson, Mark A; Wu, Hong

    2006-04-01

    Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a lipid phosphatase. PTEN inhibits the action of phosphatidylinositol-3-kinase and reduces the levels of phosphatidylinositol triphosphate, a crucial second messenger for cell proliferation and survival, as well as insulin signaling. In this study, we deleted Pten specifically in the insulin producing beta cells during murine pancreatic development. Pten deletion leads to increased cell proliferation and decreased cell death, without significant alteration of beta-cell differentiation. Consequently, the mutant pancreas generates more and larger islets, with a significant increase in total beta-cell mass. PTEN loss also protects animals from developing streptozotocin-induced diabetes. Our data demonstrate that PTEN loss in beta cells is not tumorigenic but beneficial. This suggests that modulating the PTEN-controlled signaling pathway is a potential approach for beta-cell protection and regeneration therapies.

  2. AIF inhibits tumor metastasis by protecting PTEN from oxidation.

    PubMed

    Shen, Shao-Ming; Guo, Meng; Xiong, Zhong; Yu, Yun; Zhao, Xu-Yun; Zhang, Fei-Fei; Chen, Guo-Qiang

    2015-11-01

    Apoptosis-inducing factor (AIF) exerts dual roles on cell death and survival, but its substrates as a putative oxidoreductase and roles in tumorigenesis remain elusive. Here, we report that AIF physically interacts with and inhibits the oxidation of phosphatase and tensin homolog on chromosome ten (PTEN), a tumor suppressor susceptible for oxidation-mediated inactivation. More intriguingly, we also identify PTEN as a mitochondrial protein and the ectopic expression of mitochondrial targeting sequence-carrying PTEN almost completely inhibits Akt phosphorylation in PTEN-deficient cells. AIF knockdown causes oxidation-mediated inactivation of the lipid phosphatase activity of PTEN, with ensuing activation of Akt kinase, phosphorylation of the Akt substrate GSK-3β, and activation of β-catenin signaling in cancer cells. Through its effect on β-catenin signaling, AIF inhibits epithelial-mesenchymal transition (EMT) and metastasis of cancer cells in vitro and in orthotopically implanted xenografts. Accordingly, the expression of AIF is correlated with the survival of human patients with cancers of multiple origins. These results identify PTEN as the substrate of AIF oxidoreductase and reveal a novel function for AIF in controlling tumor metastasis.

  3. Controlling PTEN (Phosphatase and Tensin Homolog) Stability: A DOMINANT ROLE FOR LYSINE 66.

    PubMed

    Gupta, Amit; Leslie, Nicholas R

    2016-08-26

    Phosphatase and tensin homolog (PTEN) is a phosphoinositide lipid phosphatase and one of the most frequently disrupted tumor suppressors in many forms of cancer, with even small reductions in the expression levels of PTEN promoting cancer development. Although the post-translational ubiquitination of PTEN can control its stability, activity, and localization, a detailed understanding of how PTEN ubiquitination integrates with other cellular regulatory processes and may be dysregulated in cancer has been hampered by a poor understanding of the significance of ubiquitination at individual sites. Here we show that Lys(66) is not required for cellular activity, yet dominates over other PTEN ubiquitination sites in the regulation of protein stability. Notably, combined mutation of other sites (Lys(13), Lys(80), and Lys(289)) has relatively little effect on protein expression, protein stability, or PTEN polyubiquitination. The present work identifies a key role for Lys(66) in the regulation of PTEN expression and provides both an opportunity to improve the stability of PTEN as a protein therapy and a mechanistic basis for efforts to stabilize endogenous PTEN. PMID:27405757

  4. Controlling PTEN (Phosphatase and Tensin Homolog) Stability: A DOMINANT ROLE FOR LYSINE 66.

    PubMed

    Gupta, Amit; Leslie, Nicholas R

    2016-08-26

    Phosphatase and tensin homolog (PTEN) is a phosphoinositide lipid phosphatase and one of the most frequently disrupted tumor suppressors in many forms of cancer, with even small reductions in the expression levels of PTEN promoting cancer development. Although the post-translational ubiquitination of PTEN can control its stability, activity, and localization, a detailed understanding of how PTEN ubiquitination integrates with other cellular regulatory processes and may be dysregulated in cancer has been hampered by a poor understanding of the significance of ubiquitination at individual sites. Here we show that Lys(66) is not required for cellular activity, yet dominates over other PTEN ubiquitination sites in the regulation of protein stability. Notably, combined mutation of other sites (Lys(13), Lys(80), and Lys(289)) has relatively little effect on protein expression, protein stability, or PTEN polyubiquitination. The present work identifies a key role for Lys(66) in the regulation of PTEN expression and provides both an opportunity to improve the stability of PTEN as a protein therapy and a mechanistic basis for efforts to stabilize endogenous PTEN.

  5. Molecular Features of Phosphatase and Tensin Homolog (PTEN) Regulation by C-terminal Phosphorylation.

    PubMed

    Chen, Zan; Dempsey, Daniel R; Thomas, Stefani N; Hayward, Dawn; Bolduc, David M; Cole, Philip A

    2016-07-01

    PTEN is a tumor suppressor that functions to negatively regulate the PI3K/AKT pathway as the lipid phosphatase for phosphatidylinositol 3,4,5-triphosphate. Phosphorylation of a cluster of Ser/Thr residues (amino acids 380-385) on the C-terminal tail serves to alter the conformational state of PTEN from an open active state to a closed inhibited state, resulting in a reduction of plasma membrane localization and inhibition of enzyme activity. The relative contribution of each phosphorylation site to PTEN autoinhibition and the structural basis for the conformational closure is still unclear. To further the structural understanding of PTEN regulation by C-terminal tail phosphorylation, we used protein semisynthesis to insert stoichiometric and site-specific phospho-Ser/Thr(s) in the C-terminal tail of PTEN. Additionally, we employed photo-cross-linking to map the intramolecular PTEN interactions of the phospho-tail. Systematic evaluation of the PTEN C-tail phospho-cluster showed autoinhibition, and conformational closure was influenced by the aggregate effect of multiple phospho-sites rather than dominated by a single phosphorylation site. Moreover, photo-cross-linking suggested a direct interaction between the PTEN C-tail and a segment in the N-terminal region of the catalytic domain. Mutagenesis experiments provided additional insights into how the PTEN phospho-tail interacts with both the C2 and catalytic domains.

  6. Deregulation of the EGFR/PI3K/PTEN/Akt/mTORC1 pathway in breast cancer: possibilities for therapeutic intervention

    PubMed Central

    Davis, Nicole M.; Sokolosky, Melissa; Stadelman, Kristin; Abrams, Stephen L.; Libra, Massimo; Candido, Saverio; Nicoletti, Ferdinando; Polesel, Jerry; Maestro, Roberta; D’Assoro, Antonino; Drobot, Lyudmyla; Rakus, Dariusz; Gizak, Agnieszka; Laidler, Piotr; Dulińska-Litewka, Joanna; Basecke, Joerg; Mijatovic, Sanja; Maksimovic-Ivanic, Danijela; Montalto, Giuseppe; Cervello, Melchiorre; Fitzgerald, Timothy L.; Demidenko, Zoya N.; Martelli, Alberto M.; Cocco, Lucio; Steelman, Linda S.; McCubrey, James A.

    2014-01-01

    The EGFR/PI3K/PTEN/Akt/mTORC1/GSK-3 pathway plays prominent roles in malignant transformation, prevention of apoptosis, drug resistance and metastasis. The expression of this pathway is frequently altered in breast cancer due to mutations at or aberrant expression of: HER2, ERalpha, BRCA1, BRCA2, EGFR1, PIK3CA, PTEN, TP53, RB as well as other oncogenes and tumor suppressor genes. In some breast cancer cases, mutations at certain components of this pathway (e.g., PIK3CA) are associated with a better prognosis than breast cancers lacking these mutations. The expression of this pathway and upstream HER2 has been associated with breast cancer initiating cells (CICs) and in some cases resistance to treatment. The anti-diabetes drug metformin can suppress the growth of breast CICs and herceptin-resistant HER2+ cells. This review will discuss the importance of the EGFR/PI3K/PTEN/Akt/mTORC1/GSK-3 pathway primarily in breast cancer but will also include relevant examples from other cancer types. The targeting of this pathway will be discussed as well as clinical trials with novel small molecule inhibitors. The targeting of the hormone receptor, HER2 and EGFR1 in breast cancer will be reviewed in association with suppression of the EGFR/PI3K/PTEN/Akt/mTORC1/GSK-3 pathway. PMID:25051360

  7. Molecular alterations of Ras-Raf-mitogen-activated protein kinase and phosphatidylinositol 3-kinase-Akt signaling pathways in colorectal cancers from a tertiary hospital at Kuala Lumpur, Malaysia.

    PubMed

    Yip, Wai Kien; Choo, Chee Wei; Leong, Vincent Ching-Shian; Leong, Pooi Pooi; Jabar, Mohd Faisal; Seow, Heng Fong

    2013-10-01

    Molecular alterations in KRAS, BRAF, PIK3CA, and PTEN have been implicated in designing targeted therapy for colorectal cancer (CRC). The present study aimed to determine the status of these molecular alterations in Malaysian CRCs as such data are not available in the literature. We investigated the mutations of KRAS, BRAF, and PTEN, the gene amplification of PIK3CA, and the protein expression of PTEN and phosphatidylinositol 3-kinase (PI3K) catalytic subunit (p110α) by direct DNA sequencing, quantitative real-time PCR, and immunohistochemistry, respectively, in 49 CRC samples. The frequency of KRAS (codons 12, 13, and 61), BRAF (V600E), and PTEN mutations, and PIK3CA amplification was 25.0% (11/44), 2.3% (1/43), 0.0% (0/43), and 76.7% (33/43), respectively. Immunohistochemical staining demonstrated loss of PTEN protein in 54.5% (24/44) of CRCs and no significant difference in PI3K p110α expression between CRCs and the adjacent normal colonic mucosa (p = 0.380). PIK3CA amplification was not associated with PI3K p110α expression level, but associated with male cases (100% of male cases vs 56% of female cases harbored amplified PIK3CA, p = 0.002). PI3K p110α expression was significantly higher (p = 0.041) in poorly/moderately differentiated carcinoma compared with well-differentiated carcinoma. KRAS mutation, PIK3CA amplification, PTEN loss, and PI3K p110α expression did not correlate with Akt phosphorylation or Ki-67 expression. KRAS mutation, PIK3CA amplification, and PTEN loss were not mutually exclusive. This is the first report on CRC in Malaysia showing comparable frequency of KRAS mutation and PTEN loss, lower BRAF mutation rate, higher PIK3CA amplification frequency, and rare PTEN mutation, as compared with published reports.

  8. Carbon Nanomaterials Alter Global Gene Expression Profiles.

    PubMed

    Woodman, Sara; Short, John C W; McDermott, Hyoeun; Linan, Alexander; Bartlett, Katelyn; Gadila, Shiva Kumar Goud; Schmelzle, Katie; Wanekaya, Adam; Kim, Kyoungtae

    2016-05-01

    Carbon nanomaterials (CNMs), which include carbon nanotubes (CNTs) and their derivatives, have diverse technological and biomedical applications. The potential toxicity of CNMs to cells and tissues has become an important emerging question in nanotechnology. To assess the toxicity of CNTs and fullerenol C60(OH)24, we in the present work used the budding yeast Saccharomyces cerevisiae, one of the simplest eukaryotic organisms that share fundamental aspects of eukaryotic cell biology. We found that treatment with CNMs, regardless of their physical shape, negatively affected the growth rates, end-point cell densities and doubling times of CNM-exposed yeast cells when compared to unexposed cells. To investigate potential mechanisms behind the CNMs-induced growth defects, we performed RNA-Seq dependent transcriptional analysis and constructed global gene expression profiles of fullerenol C60(OH)24- and CNT-treated cells. When compared to non-treated control cells, CNM-treated cells displayed differential expression of genes whose functions are implicated in membrane transporters and stress response, although differentially expressed genes were not consistent between CNT- and fullerenol C60(OH)24-treated groups, leading to our conclusion that CNMs could serve as environmental toxic factors to eukaryotic cells. PMID:27483901

  9. Activating PTEN by COX-2 inhibitors antagonizes radiation-induced AKT activation contributing to radiosensitization.

    PubMed

    Meng, Zhen; Gan, Ye-Hua

    2015-05-01

    Radiotherapy is still one of the most effective nonsurgical treatments for many tumors. However, radioresistance remains a major impediment to radiotherapy. Although COX-2 inhibitors can induce radiosensitization, the underlying mechanism is not fully understood. In this study, we showed that COX-2 selective inhibitor celecoxib enhanced the radiation-induced inhibition of cell proliferation and apoptosis in HeLa and SACC-83 cells. Treatment with celecoxib alone dephosphorylated phosphatase and tensin homolog deleted on chromosome ten (PTEN), promoted PTEN membrane translocation or activation, and correspondingly dephosphorylated or inactivated protein kinase B (AKT). By contrast, treatment with radiation alone increased PTEN phosphorylation, inhibited PTEN membrane translocation and correspondingly activated AKT in the two cell lines. However, treatment with celecoxib or another COX-2 selective inhibitor (valdecoxib) completely blocked radiation-induced increase of PTEN phosphorylation, rescued radiation-induced decrease in PTEN membrane translocation, and correspondingly inactivated AKT. Moreover, celecoxib could also upregulate PTEN protein expression by downregulating Sp1 expression, thereby leading to the activation of PTEN transcription. Our results suggested that COX-2 inhibitors could enhance radiosensitization at least partially by activating PTEN to antagonize radiation-induced AKT activation.

  10. Inhibition of autophagy induced by PTEN loss promotes intrinsic breast cancer resistance to trastuzumab therapy.

    PubMed

    Ning, Liao; Guo-Chun, Zhang; Sheng-Li, An; Xue-Rui, Li; Kun, Wang; Jian, Zu; Chong-Yang, Ren; Ling-Zhu, Wen; Hai-Tong, Lv

    2016-04-01

    This study aims to explore the effects of the phosphatase and tension homolog (PTEN) expression level on autophagic status and on the resistance of breast cancer to trastuzumab treatment. PTEN and LC3I/II were knocked down with shRNA expression vectors, which were transfected into estrogen receptor (ER)-positive breast cancer cell lines. After trastuzumab treatment, the changes in the autophagy signal transduction pathways and autophagic proteins (LC3I/II, p62, LAMP, and cathepsin B) in these stably transfected cells were detected using western blot. The cells were also orthotopically implanted into nude mice to explore the influence of PTEN knockdown on tumor size, cell viability, and autophagic proteins after trastuzumab treatment. Similar determinations were performed using the LC3I/II overexpressed shPTEN breast cancer cells (LC3I/II-shPTEN). Downregulation of PTEN and autophagic proteins LC3-I and LC3-II was observed in resistant human breast cancer samples. Knockdown of PTEN and PTEN+ LC3I/II with shRNA in breast cancer cells resulted in increased resistance to trastuzumab. Consistently, trastuzumab treatment could not effectively reduce tumor size. Significant decreases in the levels of autophagic proteins LC3I/II, LAMP, p62, cathepsin B, and PI3K-Akt-mTOR and the signaling pathway protein Akt were found in PTEN knockdown cells, compared to the PTEN normal group, after trastuzumab administration, both in vitro and in vivo. However, these findings were reversed with the LC3I/II-shPTEN treatment. Therefore, the loss of PTEN may promote the development of primary resistance to trastuzumab in breast cancer via autophagy defects.

  11. PTEN Phosphorylation and Nuclear Export Mediate Free Fatty Acid-Induced Oxidative Stress

    PubMed Central

    Wu, Yong; Zhou, Hillary; Wu, Ke; Lee, Sangkyu; Li, Ruijin

    2014-01-01

    Abstract Aim: Oxidative stress induced by free fatty acids (FFA) contributes to metabolic syndrome-associated development of cardiovascular diseases, yet molecular mechanisms remain poorly understood. This study aimed at establishing whether phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and its subcellular location play a role in FFA-induced endothelial oxidative stress. Results: Exposing human endothelial cells (ECs) with FFA activated mammalian target of rapamycin (mTOR)/S6K pathway, and upon activation, S6K directly phosphorylated PTEN at S380. Phosphorylation of PTEN increased its interaction with its deubiquitinase USP7 in the nucleus, leading to PTEN deubiquitination and nuclear export. The reduction of PTEN in the nucleus, in turn, decreased p53 acetylation and transcription, reduced the expression of the p53 target gene glutathione peroxidase-1 (GPX1), resulting in reactive oxygen species (ROS) accumulation and endothelial damage. Finally, C57BL/6J mice fed with high-fat atherogenic diet (HFAD) showed PTEN nuclear export, decreased p53 and GPX1 protein expressions, elevated levels of ROS, and significant lesions in aortas. Importantly, inhibition of mTOR or S6K effectively blocked these effects, suggesting that mTOR/S6K pathway mediates HFAD-induced oxidative stress and vascular damage via PTEN/p53/GPX1 inhibition in vivo. Innovation: Our study demonstrated for the first time that S6K directly phosphorylated PTEN at S380 under high FFA conditions, and this phosphorylation mediated FFA-induced endothelial oxidative stress. Furthermore, we showed that S380 phosphorylation affected PTEN monoubiquitination and nuclear localization, providing the first example of coordinated regulation of PTEN nuclear localization via phosphorylation and ubiquitination. Conclusion: Our studies provide a novel mechanism by which hyperlipidemia causes vascular oxidative damage through the phosphorylation of PTEN, blocking of PTEN nuclear function, and inhibition

  12. Adenovirus-mediated transfer of the PTEN gene inhibits human colorectal cancer growth in vitro and in vivo.

    PubMed

    Saito, Y; Swanson, X; Mhashilkar, A M; Oida, Y; Schrock, R; Branch, C D; Chada, S; Zumstein, L; Ramesh, R

    2003-11-01

    The tumor-suppressor gene PTEN encodes a multifunctional phosphatase that is mutated in a variety of human cancers. PTEN inhibits the phosphatidylinositol 3-kinase pathway and downstream functions, including activation of Akt/protein kinase B (PKB), cell survival, and cell proliferation in tumor cells carrying mutant- or deletion-type PTEN. In such tumor cells, enforced expression of PTEN decreases cell proliferation through cell-cycle arrest at G1 phase accompanied, in some cases, by induction of apoptosis. More recently, the tumor-suppressive effect of PTEN has been reported in ovarian and thyroid tumors that are wild type for PTEN. In the present study, we examined the tumor-suppressive effect of PTEN in human colorectal cancer cells that are wild type for PTEN. Adenoviral-mediated transfer of PTEN (Ad-PTEN) suppressed cell growth and induced apoptosis significantly in colorectal cancer cells (DLD-1, HT29, and SW480) carrying wtPTEN than in normal colon fibroblast cells (CCD-18Co) carrying wtPTEN. This suppression was induced through downregulation of the Akt/PKB pathway, dephosphorylation of focal adhesion kinase (FAK) and mitogen-activated protein kinase (MAPK) and cell-cycle arrest at the G2/M phase, but not the G1 phase. Furthermore, treatment of human colorectal tumor xenografts (HT-29, and SW480) with Ad-PTEN resulted in significant (P=0.01) suppression of tumor growth. These results indicate that Ad-PTEN exerts its tumor-suppressive effect on colorectal cancer cells through inhibition of cell-cycle progression and induction of cell death. Thus Ad-PTEN may be a potential therapeutic for treatment of colorectal cancers. PMID:14528320

  13. An inducible knockout mouse to model the cell-autonomous role of PTEN in initiating endometrial, prostate and thyroid neoplasias

    PubMed Central

    Mirantes, Cristina; Eritja, Núria; Dosil, Maria Alba; Santacana, Maria; Pallares, Judit; Gatius, Sónia; Bergadà, Laura; Maiques, Oscar; Matias-Guiu, Xavier; Dolcet, Xavier

    2013-01-01

    SUMMARY PTEN is one of the most frequently mutated tumor suppressor genes in human cancers. The role of PTEN in carcinogenesis has been validated by knockout mouse models. PTEN heterozygous mice develop neoplasms in multiple organs. Unfortunately, the embryonic lethality of biallelic excision of PTEN has inhibited the study of complete PTEN deletion in the development and progression of cancer. By crossing PTEN conditional knockout mice with transgenic mice expressing a tamoxifen-inducible Cre-ERT under the control of a chicken actin promoter, we have generated a tamoxifen-inducible mouse model that allows temporal control of PTEN deletion. Interestingly, administration of a single dose of tamoxifen resulted in PTEN deletion mainly in epithelial cells, but not in stromal, mesenchymal or hematopoietic cells. Using the mT/mG double-fluorescent Cre reporter mice, we demonstrate that epithelial-specific PTEN excision was caused by differential Cre activity among tissues and cells types. Tamoxifen-induced deletion of PTEN resulted in extremely rapid and consistent formation of endometrial in situ adenocarcinoma, prostate intraepithelial neoplasia and thyroid hyperplasia. We also analyzed the role of PTEN ablation in other epithelial cells, such as the tubular cells of the kidney, hepatocytes, colonic epithelial cells or bronchiolar epithelium, but those tissues did not exhibit neoplastic growth. Finally, to validate this model as a tool to assay the efficacy of anti-tumor drugs in PTEN deficiency, we administered the mTOR inhibitor everolimus to mice with induced PTEN deletion. Everolimus dramatically reduced the progression of endometrial proliferations and significantly reduced thyroid hyperplasia. This model could be a valuable tool to study the cell-autonomous mechanisms involved in PTEN-loss-induced carcinogenesis and provides a good platform to study the effect of anti-neoplastic drugs on PTEN-negative tumors. PMID:23471917

  14. Down-regulation of PTEN by HCV core protein through activating nuclear factor-κB

    PubMed Central

    Zhang, Yong; Li, Rong-Qing; Feng, Xu-Dong; Zhang, Yan-Hua; Wang, Li

    2014-01-01

    The hepatitis C virus (HCV) core protein is an important causative agent in HCV related hepatocellular carcinoma (HCC). Tumor suppressor gene PTEN appears to act in the liver at the crossroad of processes controlling cell proliferation. In this study we investigated the effect of the HCV core protein on the PTEN pathway in hepatocarcinogenesis. The HCV core was transfected stably into HepG2 cell. The effect of HCV core on cell proliferation and viability were detected by 3-(4, 5)-dimethylthiahiazo-(-z-y1)-3, 5-di-phenytetrazoliumromide (MTT) assay, clonogenic survival assay and Fluorescence Activating Cell Sorter (FACS) analysis. The expressions of PTEN were detected by real time RT-PCR and/or Western blot analysis, also the mechanism of down-regulation of PTEN was explored by western blot, luciferase assay and RNA interference. We found the HCV core promoted cell proliferation, survival and G2/M phase accumulation. It downregulated PTEN at mRNA and protein level and activated PTEN downstream gene Akt accompanied with NF-κB activation. Furthermore, the inhibition of HCV core by its specific shRNAs decreased the effect of growth promotion and G2/M phase arrest, inhibited the expression of nuclear p65 and increased PTEN expression. The activity of PTEN was restored when treated with NF-κB inhibitor PDTC. By luciferase assay we found that NF-κB inhibited PTEN promoter transcription activity directly in HCV core cells, while PDTC was contrary. Our study suggests that HCV proteins could modulate PTEN by activating NF-κB. Furthermore strategies designed to restore the expression of PTEN may be promising therapies for preventing HCV dependent hepatocarcinogenesis. PMID:25550771

  15. Soy peptide lunasin induces pten-mediated apoptosis in human breast cancer cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The tumor suppressor PTEN inhibits the AKT signaling pathway whose unrestrained activity underlies many human malignancies. Previously we showed that dietary intake of soy protein isolate (SPI) enhanced PTEN expression in mammary tissue of rats with lower NMU-induced mammary tumor incidence relative...

  16. Igf2 ligand dependency of Pten(+/-) developmental and tumour phenotypes in the mouse.

    PubMed

    Church, D N; Phillips, B R; Stuckey, D J; Barnes, D J; Buffa, F M; Manek, S; Clarke, K; Harris, A L; Carter, E J; Hassan, A B

    2012-08-01

    The tumour suppressor PTEN is a key negative regulator of the PI3K-Akt pathway, and is frequently either reduced or lost in human tumours. Murine genetic studies have confirmed that reduction of Pten promotes tumourigenesis in multiple organs, and demonstrated dependency of tumour development on the activation of downstream components such as Akt. Insulin-like growth factors (IGFs) act via IGF1R to activate the PI3K-Akt pathway, and are commonly upregulated in cancer. A context-dependent interplay between IGFs and PTEN exists in normal tissue and tumours; increased IGF2 ligand supply induces Pten expression creating an autoregulatory negative feedback loop, whereas complete loss of PTEN may either cooperate with IGF overexpression in tumour promotion, or result in desensitisation to IGF ligand. However, it remains unknown whether neoplasia associated with Pten loss is dependent on upstream IGF ligand supply in vivo. We evaluated this by generation of Pten(+/-) mice with differing allelic dosage of Igf2, an imprinted gene encoding the potent embryonic and tumour growth factor Igf2. We show that biallelic Igf2 supply potentiates a previously unreported Pten(+/-) placental phenotype and results in strain-dependent cardiac hyperplasia and neonatal lethality. Importantly, we also show that the effects of Pten loss in vivo are modified by Igf2 supply, as lack of Igf2 results in extended survival and delayed tumour development while biallelic supply is associated with reduced lifespan and accelerated neoplasia in females. Furthermore, we demonstrate that reduction of PTEN protein to heterozygote levels in human MCF7 cells is associated with increased proliferation in response to IGF2, and does not result in desensitisation to IGF2 signalling. These data indicate that the effects of Pten loss at heterozygote levels commonly observed in human tumours are modified by Igf2 ligand, and emphasise the importance of the evaluation of upstream pathways in tumours with Pten loss

  17. Alterations in cathepsin L expression in lung cancers.

    PubMed

    Okudela, Koji; Mitsui, Hideaki; Woo, Tetsukan; Arai, Hiromasa; Suzuki, Takehisa; Matsumura, Mai; Kojima, Yoko; Umeda, Shigeaki; Tateishi, Yoko; Masuda, Munetaka; Ohashi, Kenichi

    2016-07-01

    We herein investigated the potential role of cathepsin L in lung carcinogenesis. Lung cancer cell lines and surgically resected tumors were examined for the expression of the cathepsin L protein and copy number alterations in its gene locus. Cathepsin L was stably expressed in bronchiolar epithelial cells. Neoplastic cells expressed cathepsin L at various levels, whereas its expression was completely lost in most of the lung cancer cell lines (63.6%, 7/11) examined. Furthermore, expression levels were lower in a large fraction of lung tumors (69.5%, 139/200) than in bronchiolar epithelia. The expression of cathepsin L was lost in some tumors (16.0%, 32/200). In adenocarcinomas, expression levels were significantly lower in high-grade tumors than in low-grade tumors (one-way ANOVA, P < 0.0500). Copy number alterations were found in 18.0% (36 [32 gain + 4 loss] /200) of lung tumors. No relationship existed between cathepsin L protein expression levels and the copy number of its gene locus (Spearman's rank-order correlation, P = 0.3096). Collectively, these results suggest that the down-regulated expression of cathepsin L, which is caused by an undefined mechanism other than copy number alterations, is involved in the progression of lung adenocarcinomas.

  18. PTEN Increases Autophagy and Inhibits the Ubiquitin-Proteasome Pathway in Glioma Cells Independently of its Lipid Phosphatase Activity

    PubMed Central

    Errafiy, Rajaa; Aguado, Carmen; Ghislat, Ghita; Esteve, Juan M.; Gil, Anabel; Loutfi, Mohammed; Knecht, Erwin

    2013-01-01

    Two major mechanisms of intracellular protein degradation, autophagy and the ubiquitin-proteasome pathway, operate in mammalian cells. PTEN, which is frequently mutated in glioblastomas, is a tumor suppressor gene that encodes a dual specificity phosphatase that antagonizes the phosphatidylinositol 3-kinase class I/AKT/mTOR pathway, which is a key regulator of autophagy. Here, we investigated in U87MG human glioma cells the role of PTEN in the regulation of autophagy and the ubiquitin-proteasome pathway, because both are functionally linked and are relevant in cancer progression. Since U87MG glioma cells lack a functional PTEN, we used stable clones that express, under the control of a tetracycline-inducible system (Tet-on), wild-type PTEN and two of its mutants, G129E-PTEN and C124S-PTEN, which, respectively, lack the lipid phosphatase activity only and both the lipid and the protein phosphatase activities of this protein. Expression of PTEN in U87MG glioma cells decreased proteasome activity and also reduced protein ubiquitination. On the contrary, expression of PTEN increased the autophagic flux and the lysosomal mass. Interestingly, and although PTEN negatively regulates the phosphatidylinositol 3-kinase class I/AKT/mTOR signaling pathway by its lipid phosphatase activity, both effects in U87MG cells were independent of this activity. These results suggest a new mTOR-independent signaling pathway by which PTEN can regulate in opposite directions the main mechanisms of intracellular protein degradation. PMID:24349488

  19. In Vitro and In Vivo Effects of Tumor Suppressor Gene PTEN on Endometriosis: An Experimental Study

    PubMed Central

    Lv, Juan; Zhu, Qiaoying; Jia, Xuemei; Yu, Ningzhu; Li, Qian

    2016-01-01

    Background Endometriosis can cause dysmenorrhea and infertility. Its pathogenesis has not yet been clarified and its treatment continues to pose enormous challenges. The protein tyrosine phosphatase (PTEN) gene is a tumor suppressor gene. The aim of this study was to investigate the role and significance of PTEN protein in the occurrence, development, and treatment of endometriosis through changes in apoptosis rate, cell cycle, and angiogenesis. Material/Methods PTEN was overexpressed and silenced in lentiviral vectors and inserted into primary endometrial cells. The changes in cell cycle and apoptosis in the different PTEN expression groups were evaluated using flow cytometry. Vessel growth mimicry was observed using 3-dimensional culture. A human-mouse chimeric endometriosis model was constructed using SCID mice. Hematoxylin and eosin staining and immunohistochemistry were used to detect pathological changes in ectopic endometrial tissues and the expression of VEGF protein in a human-mouse chimeric endometriosis mouse model. Results PTEN overexpression significantly increased apoptosis and inhibited the cell cycle compared with the silenced and control groups. Furthermore, cells expressing low PTEN levels were better able to undergo vasculogenic mimicry, and exhibited significantly increased angiogenesis compared to cells overexpressing PTEN. We found that ectopic foci were more easily formed in the endometrial tissue of SCID mice with low PTEN expression, and the VEGF expression in this group was relatively high. Conclusions PTEN inhibits the occurrence and development of endometriosis by regulating angiogenesis and the apoptosis and cell cycle of endometrial cells; therefore, we propose that the PTEN gene can be used to treat endometriosis. PMID:27744455

  20. Microenvironment-induced PTEN loss by exosomal microRNA primes brain metastasis outgrowth.

    PubMed

    Zhang, Lin; Zhang, Siyuan; Yao, Jun; Lowery, Frank J; Zhang, Qingling; Huang, Wen-Chien; Li, Ping; Li, Min; Wang, Xiao; Zhang, Chenyu; Wang, Hai; Ellis, Kenneth; Cheerathodi, Mujeeburahiman; McCarty, Joseph H; Palmieri, Diane; Saunus, Jodi; Lakhani, Sunil; Huang, Suyun; Sahin, Aysegul A; Aldape, Kenneth D; Steeg, Patricia S; Yu, Dihua

    2015-11-01

    The development of life-threatening cancer metastases at distant organs requires disseminated tumour cells' adaptation to, and co-evolution with, the drastically different microenvironments of metastatic sites. Cancer cells of common origin manifest distinct gene expression patterns after metastasizing to different organs. Clearly, the dynamic interaction between metastatic tumour cells and extrinsic signals at individual metastatic organ sites critically effects the subsequent metastatic outgrowth. Yet, it is unclear when and how disseminated tumour cells acquire the essential traits from the microenvironment of metastatic organs that prime their subsequent outgrowth. Here we show that both human and mouse tumour cells with normal expression of PTEN, an important tumour suppressor, lose PTEN expression after dissemination to the brain, but not to other organs. The PTEN level in PTEN-loss brain metastatic tumour cells is restored after leaving the brain microenvironment. This brain microenvironment-dependent, reversible PTEN messenger RNA and protein downregulation is epigenetically regulated by microRNAs from brain astrocytes. Mechanistically, astrocyte-derived exosomes mediate an intercellular transfer of PTEN-targeting microRNAs to metastatic tumour cells, while astrocyte-specific depletion of PTEN-targeting microRNAs or blockade of astrocyte exosome secretion rescues the PTEN loss and suppresses brain metastasis in vivo. Furthermore, this adaptive PTEN loss in brain metastatic tumour cells leads to an increased secretion of the chemokine CCL2, which recruits IBA1-expressing myeloid cells that reciprocally enhance the outgrowth of brain metastatic tumour cells via enhanced proliferation and reduced apoptosis. Our findings demonstrate a remarkable plasticity of PTEN expression in metastatic tumour cells in response to different organ microenvironments, underpinning an essential role of co-evolution between the metastatic cells and their microenvironment during

  1. Truncating PREX2 mutations activate its GEF activity and alter gene expression regulation in NRAS-mutant melanoma

    PubMed Central

    Lissanu Deribe, Yonathan; Shi, Yanxia; Rai, Kunal; Nezi, Luigi; Amin, Samir B.; Wu, Chia-Chin; Akdemir, Kadir C.; Mahdavi, Mozhdeh; Peng, Qian; Chang, Qing Edward; Hornigold, Kirsti; Arold, Stefan T.; Welch, Heidi C. E.; Garraway, Levi A.; Chin, Lynda

    2016-01-01

    PREX2 (phosphatidylinositol-3,4,5-triphosphate-dependent Rac-exchange factor 2) is a PTEN (phosphatase and tensin homolog deleted on chromosome 10) binding protein that is significantly mutated in cutaneous melanoma and pancreatic ductal adenocarcinoma. Here, genetic and biochemical analyses were conducted to elucidate the nature and mechanistic basis of PREX2 mutation in melanoma development. By generating an inducible transgenic mouse model we showed an oncogenic role for a truncating PREX2 mutation (PREX2E824*) in vivo in the context of mutant NRAS. Using integrative cross-species gene expression analysis, we identified deregulated cell cycle and cytoskeleton organization as significantly perturbed biological pathways in PREX2 mutant tumors. Mechanistically, truncation of PREX2 activated its Rac1 guanine nucleotide exchange factor activity, abolished binding to PTEN and activated the PI3K (phosphatidyl inositol 3 kinase)/Akt signaling pathway. We further showed that PREX2 truncating mutations or PTEN deletion induces down-regulation of the tumor suppressor and cell cycle regulator CDKN1C (also known as p57KIP2). This down-regulation occurs, at least partially, through DNA hypomethylation of a differentially methylated region in chromosome 11 that is a known regulatory region for expression of the CDKN1C gene. Together, these findings identify PREX2 as a mediator of NRAS-mutant melanoma development that acts through the PI3K/PTEN/Akt pathway to regulate gene expression of a cell cycle regulator. PMID:26884185

  2. Efficacy of targeted AKT inhibition in genetically engineered mouse models of PTEN-deficient prostate cancer.

    PubMed

    De Velasco, Marco A; Kura, Yurie; Yoshikawa, Kazuhiro; Nishio, Kazuto; Davies, Barry R; Uemura, Hirotsugu

    2016-03-29

    The PI3K/AKT pathway is frequently altered in advanced human prostate cancer mainly through the loss of functional PTEN, and presents as potential target for personalized therapy. Our aim was to determine the therapeutic potential of the pan-AKT inhibitor, AZD5363, in PTEN-deficient prostate cancer. Here we used a genetically engineered mouse (GEM) model of PTEN-deficient prostate cancer to evaluate the in vivo pharmacodynamic and antitumor activity of AZD5363 in castration-naïve and castration-resistant prostate cancer. An additional GEM model, based on the concomitant inactivation of PTEN and Trp53 (P53), was established as an aggressive model of advanced prostate cancer and was used to further evaluate clinically relevant endpoints after treatment with AZD5363. In vivo pharmacodynamic studies demonstrated that AZD5363 effectively inhibited downstream targets of AKT. AZD5363 monotherapy significantly reduced growth of tumors in castration-naïve and castration-resistant models of PTEN-deficient prostate cancer. More importantly, AZD5363 significantly delayed tumor growth and improved overall survival and progression-free survival in PTEN/P53 double knockout mice. Our findings demonstrate that AZD5363 is effective against GEM models of PTEN-deficient prostate cancer and provide lines of evidence to support further investigation into the development of treatment strategies targeting AKT for the treatment of PTEN-deficient prostate cancer.

  3. Mutational spectra of PTEN/MMAC1 gene: a tumor suppressor with lipid phosphatase activity.

    PubMed

    Ali, I U; Schriml, L M; Dean, M

    1999-11-17

    PTEN/MMAC1 (phosphatase, tensin homologue/mutated in multiple advanced cancers) is a tumor suppressor protein that has sequence homology with dual-specificity phosphatases, which are capable of dephosphorylating both tyrosine phosphate and serine/threonine phosphate residues on proteins. The in vivo function of PTEN/MMAC1 appears to be dephosphorylation of phosphotidylinositol 3,4, 5-triphosphate. The PTEN/MMAC1 gene is mutated in the germline of patients with rare autosomal dominant cancer syndromes and in subsets of specific cancers. Here we review the mutational spectra of the PTEN/MMAC1 gene in tumors from various tissues, especially endometrium, brain, prostate, and ovary, in which the gene is inactivated very frequently. Germline and somatic mutations in the PTEN/MMAC1 gene occur mostly in the protein coding region and involve the phosphatase domain and poly(A)(6) stretches. Compared with germline alterations found in the PTEN/MMAC1 gene, there is a substantially increased frequency of frameshift mutations in tumors. Glioblastomas and endometrial carcinomas appear to have distinct mutational spectra, probably reflecting differences in the underlying mechanisms of inactivation of the PTEN/MMAC1 gene in the two tissue types. Also, depending on the tissue type, the gene appears to be involved in the initiation or the progression of cancers. Further understanding of PTEN/MMAC1 gene mutations in different tumors and the physiologic consequences of these mutations is likely to open up new therapeutic opportunities for targeting this critical gene.

  4. Efficacy of targeted AKT inhibition in genetically engineered mouse models of PTEN-deficient prostate cancer

    PubMed Central

    De Velasco, Marco A.; Kura, Yurie; Yoshikawa, Kazuhiro; Nishio, Kazuto; Davies, Barry R.; Uemura, Hirotsugu

    2016-01-01

    The PI3K/AKT pathway is frequently altered in advanced human prostate cancer mainly through the loss of functional PTEN, and presents as potential target for personalized therapy. Our aim was to determine the therapeutic potential of the pan-AKT inhibitor, AZD5363, in PTEN-deficient prostate cancer. Here we used a genetically engineered mouse (GEM) model of PTEN-deficient prostate cancer to evaluate the in vivo pharmacodynamic and antitumor activity of AZD5363 in castration-naïve and castration-resistant prostate cancer. An additional GEM model, based on the concomitant inactivation of PTEN and Trp53 (P53), was established as an aggressive model of advanced prostate cancer and was used to further evaluate clinically relevant endpoints after treatment with AZD5363. In vivo pharmacodynamic studies demonstrated that AZD5363 effectively inhibited downstream targets of AKT. AZD5363 monotherapy significantly reduced growth of tumors in castration-naïve and castration-resistant models of PTEN-deficient prostate cancer. More importantly, AZD5363 significantly delayed tumor growth and improved overall survival and progression-free survival in PTEN/P53 double knockout mice. Our findings demonstrate that AZD5363 is effective against GEM models of PTEN-deficient prostate cancer and provide lines of evidence to support further investigation into the development of treatment strategies targeting AKT for the treatment of PTEN-deficient prostate cancer. PMID:26910118

  5. Caffeine exposure alters cardiac gene expression in embryonic cardiomyocytes.

    PubMed

    Fang, Xiefan; Mei, Wenbin; Barbazuk, William B; Rivkees, Scott A; Wendler, Christopher C

    2014-12-15

    Previous studies demonstrated that in utero caffeine treatment at embryonic day (E) 8.5 alters DNA methylation patterns, gene expression, and cardiac function in adult mice. To provide insight into the mechanisms, we examined cardiac gene and microRNA (miRNA) expression in cardiomyocytes shortly after exposure to physiologically relevant doses of caffeine. In HL-1 and primary embryonic cardiomyocytes, caffeine treatment for 48 h significantly altered the expression of cardiac structural genes (Myh6, Myh7, Myh7b, Tnni3), hormonal genes (Anp and BnP), cardiac transcription factors (Gata4, Mef2c, Mef2d, Nfatc1), and microRNAs (miRNAs; miR208a, miR208b, miR499). In addition, expressions of these genes were significantly altered in embryonic hearts exposed to in utero caffeine. For in utero experiments, pregnant CD-1 dams were treated with 20-60 mg/kg of caffeine, which resulted in maternal circulation levels of 37.3-65.3 μM 2 h after treatment. RNA sequencing was performed on embryonic ventricles treated with vehicle or 20 mg/kg of caffeine daily from E6.5-9.5. Differential expression (DE) analysis revealed that 124 genes and 849 transcripts were significantly altered, and differential exon usage (DEU) analysis identified 597 exons that were changed in response to prenatal caffeine exposure. Among the DE genes identified by RNA sequencing were several cardiac structural genes and genes that control DNA methylation and histone modification. Pathway analysis revealed that pathways related to cardiovascular development and diseases were significantly affected by caffeine. In addition, global cardiac DNA methylation was reduced in caffeine-treated cardiomyocytes. Collectively, these data demonstrate that caffeine exposure alters gene expression and DNA methylation in embryonic cardiomyocytes.

  6. PTEN Inhibition Improves Muscle Regeneration in Mice Fed a High-Fat Diet

    PubMed Central

    Hu, Zhaoyong; Wang, Huiling; Lee, In Hee; Modi, Swati; Wang, Xiaonan; Du, Jie; Mitch, William E.

    2010-01-01

    OBJECTIVE Mechanisms impairing wound healing in diabetes are poorly understood. To identify mechanisms, we induced insulin resistance by chronically feeding mice a high-fat diet (HFD). We also examined the regulation of phosphatidylinositol 3,4,5-trisphosphate (PIP3) during muscle regeneration because augmented IGF-1 signaling can improve muscle regeneration. RESEARCH DESIGN AND METHODS Muscle regeneration was induced by cardiotoxin injury, and we evaluated satellite cell activation and muscle maturation in HFD-fed mice. We also measured PIP3 and the enzymes regulating its level, IRS-1–associated phosphatidylinositol 3-kinase (PI3K) and PTEN. Using primary cultures of muscle, we examined how fatty acids affect PTEN expression and how PTEN knockout influences muscle growth. Mice with muscle-specific PTEN knockout were used to examine how the HFD changes muscle regeneration. RESULTS The HFD raised circulating fatty acids and impaired the growth of regenerating myofibers while delaying myofiber maturation and increasing collagen deposition. These changes were independent of impaired proliferation of muscle progenitor or satellite cells but were principally related to increased expression of PTEN, which reduced PIP3 in muscle. In cultured muscle cells, palmitate directly stimulated PTEN expression and reduced cell growth. Knocking out PTEN restored cell growth. In mice, muscle-specific PTEN knockout improved the defects in muscle repair induced by HFD. CONCLUSIONS Insulin resistance impairs muscle regeneration by preventing myofiber maturation. The mechanism involves fatty acid–stimulated PTEN expression, which lowers muscle PIP3. If similar pathways occur in diabetic patients, therapeutic strategies directed at improving the repair of damaged muscle could include suppression of PTEN activity. PMID:20200318

  7. Altering sensorimotor feedback disrupts visual discrimination of facial expressions.

    PubMed

    Wood, Adrienne; Lupyan, Gary; Sherrin, Steven; Niedenthal, Paula

    2016-08-01

    Looking at another person's facial expression of emotion can trigger the same neural processes involved in producing the expression, and such responses play a functional role in emotion recognition. Disrupting individuals' facial action, for example, interferes with verbal emotion recognition tasks. We tested the hypothesis that facial responses also play a functional role in the perceptual processing of emotional expressions. We altered the facial action of participants with a gel facemask while they performed a task that involved distinguishing target expressions from highly similar distractors. Relative to control participants, participants in the facemask condition demonstrated inferior perceptual discrimination of facial expressions, but not of nonface stimuli. The findings suggest that somatosensory/motor processes involving the face contribute to the visual perceptual-and not just conceptual-processing of facial expressions. More broadly, our study contributes to growing evidence for the fundamentally interactive nature of the perceptual inputs from different sensory modalities.

  8. Synergistic tumor suppression by adenovirus-mediated ING4/PTEN double gene therapy for gastric cancer.

    PubMed

    Zhang, H; Zhou, X; Xu, C; Yang, J; Xiang, J; Tao, M; Xie, Y

    2016-01-01

    Both inhibitor of growth 4 (ING4) and phosphatase and tensin homolog (PTEN) have been shown to be strong candidate tumor suppressors. However, the combined efficacy of ING4 and PTEN for human gastric cancer remains to be determined. In this report, we constructed a multiple promoter expression cassette-based recombinant adenovirus coexpressing ING4 and PTEN (AdVING4/PTEN), assessed the combined effects of AdVING4/PTEN on gastric cancer using wild-type p53 AGS and SNU-1 human gastric cancer cell lines, and elucidated its underlying mechanisms. We found that AdVING4/PTEN-induced synergistic growth inhibition and apoptosis in vitro AGS or SNU-1 tumor cells and in vivo AGS xenografted tumors subcutaneously inoculated in athymic BALB/c nude mice. Mechanistically, AdVING4/PTEN exhibited an enhanced effect on upregulation of p53, Ac-p53 (K382), P21, Bax, PUMA, Noxa, cleaved Caspase-9, cleaved Caspase-3 and cleaved PARP as well as downregulation of Bcl-2 in vitro and in vivo. In addition, AdVING4/PTEN synergistically downregulated tumor vessel CD34 expression and reduced microvessel density, and additively inhibited vascular endothelial growth factor (VEGF) expression in vivo. The synergistic tumor suppression elicited by AdVING4/PTEN was closely associated with the synergistic induction of apoptosis possibly via enhancement of endogenous p53 responses through cooperatively facilitating p53's stability and acetylation, and the synergistic inhibition of tumor angiogenesis probably via overlapping reduction of VEGF through cooperatively downregulating hypoxia inducible factor-1α's level and transcription activity. Thus, our results indicate that cancer gene therapy combining ING4 and PTEN may constitute a novel and effective therapeutic modality for human gastric cancer and other cancers.

  9. Fish oil suppresses cell growth and metastatic potential by regulating PTEN and NF-κB signaling in colorectal cancer.

    PubMed

    Kansal, Shevali; Bhatnagar, Archana; Agnihotri, Navneet

    2014-01-01

    Homeostasis in eukaryotic tissues is tightly regulated by an intricate balance of the prosurvival and antisurvival signals. The tumor suppressor PTEN (phosphatase and tensin homolog deleted on chromosome 10), a dual-specificity phosphatase, plays a functional role in cell cycle arrest and apoptosis. NF-κB and its downstream regulators (such as VEGF) play a central role in prevention of apoptosis, promotion of inflammation and tumor growth. Therefore, we thought to estimate the expression of PTEN, Poly-ADP-ribose polymerase (PARP), NF-κBp50, NF-κBp65 and VEGF to evaluate the effect of supplementation of fish oil on apoptotic and inflammatory signaling in colon carcinoma. Male wistar rats in Group I received purified diet while Group II and III received modified diet supplemented with FO∶CO(1∶1)&FO∶CO(2.5∶1) respectively. These were further subdivided into controls receiving ethylenediamine-tetra acetic-acid and treated groups received dimethylhydrazine-dihydrochloride (DMH)/week for 4 weeks. Animals sacrificed 48 hours after last injection constituted initiation phase and that sacrificed after 16 weeks constituted post-initiation phase. We have analysed expression of PTEN, NF-κBp50, NF-κBp65 by flowcytometer and nuclear localization of NF-κB by immunofluorescence. PARP and VEGF were assessed by immunohistochemistry. In the initiation phase, animals receiving DMH have shown increased % of apoptotic cells, PTEN, PARP, NF-κBp50, NF-κBp65 and VEGF however in post-initiation phase no significant alteration in apoptosis with decreased PTEN and increased PARP, NF-κBp50, NF-κBp65 and VEGF were observed as compared to control animals. On treatment with both ratios of fish oil in both the phases, augmentation in % of apoptotic cells, decreased PTEN, PARP, NF-κBp50, NF-κBp65 and VEGF were documented with respect to DMH treated animals with effect being more exerted with higher ration in post-initiation phase. Hence, fish oil activates apoptosis, diminishes

  10. Altered expression of Ano1 variants in human diabetic gastroparesis.

    PubMed

    Mazzone, Amelia; Bernard, Cheryl E; Strege, Peter R; Beyder, Arthur; Galietta, Luis J V; Pasricha, Pankaj J; Rae, James L; Parkman, Henry P; Linden, David R; Szurszewski, Joseph H; Ördög, Tamas; Gibbons, Simon J; Farrugia, Gianrico

    2011-04-15

    Diabetes affects many organs including the stomach. Altered number and function of interstitial cells of Cajal (ICC), the gastrointestinal pacemaker cells, underlie a number of gastrointestinal motility disorders, including diabetic gastroparesis. In the muscle layers, ICC selectively express Ano1, thought to underlie classical Ca(2+)-activated Cl(-) currents. Mice homozygous for Ano1 knock-out exhibit abnormal ICC function and motility. Several transcripts for Ano1 are generated by alternative splicing of four exons. Here, we report expression levels of transcripts encoded by alternative splicing of Ano1 gene in gastric muscles of patients with diabetic gastroparesis and nondiabetic control tissues. Expression of mRNA from two alternatively transcribed exons are significantly different between patients and controls. Furthermore, patients with diabetic gastroparesis express mRNA for a previously unknown variant of Ano1. The 5' end of this novel variant lacks exons 1 and 2 and part of exon 3. Expression of this variant in HEK cells produces a decreased density of Ca(2+)-activated Cl(-) currents that exhibit slower kinetics compared with the full-length Ano1. These results identify important changes in expression and splicing of Ano1 in patients with diabetic gastroparesis that alter the electrophysiological properties of the channel. Changes in Ano1 expression in ICC may directly contribute to diabetic gastroparesis. PMID:21349842

  11. Alterations in peripheral blood lymphocyte cytokine expression in obesity

    PubMed Central

    O'Rourke, R W; Kay, T; Lyle, E A; Traxler, S A; Deveney, C W; Jobe, B A; Roberts, C T; Marks, D; Rosenbaum, J T

    2006-01-01

    Obesity is characterized by alterations in immune and inflammatory function. In order to evaluate the potential role of cytokine expression by peripheral blood mononuclear cells (PBMC) in obesity-associated inflammation, we studied serum protein levels and mRNA levels in PBMC of interleukin (IL)-6, IL-1β, tumour necrosis factor (TNF)-α and IL-1Ra in nine lean and 10 obese subjects. Serum IL-1β was undetectable, IL-1Ra serum levels were elevated, serum levels of TNF-α were decreased and serum levels of IL-6 were similar in obese subjects compared to lean subjects, while transcript levels of IL-6, IL-1β and TNF-α, but not IL-1Ra, were decreased in PBMC from obese subjects. PBMC from obese subjects did, however, up-regulate cytokine expression in response to leptin. Thus, obesity-associated changes in IL-1Ra serum levels and IL-6 mRNA levels were not correlated with changes in cognate mRNA and serum levels, respectively, while TNF-α serum levels and PBMC mRNA levels were both decreased in obese patients. While immune alterations in obesity are manifest in peripheral blood lymphocytes, the general lack of correlation between altered serum levels and altered PBMC gene expression suggests that PBMC may not be the source of aberrant serum cytokine levels in obesity. PMID:16968396

  12. PTEN deficiency reprogrammes human neural stem cells towards a glioblastoma stem cell-like phenotype.

    PubMed

    Duan, Shunlei; Yuan, Guohong; Liu, Xiaomeng; Ren, Ruotong; Li, Jingyi; Zhang, Weizhou; Wu, Jun; Xu, Xiuling; Fu, Lina; Li, Ying; Yang, Jiping; Zhang, Weiqi; Bai, Ruijun; Yi, Fei; Suzuki, Keiichiro; Gao, Hua; Esteban, Concepcion Rodriguez; Zhang, Chuanbao; Izpisua Belmonte, Juan Carlos; Chen, Zhiguo; Wang, Xiaomin; Jiang, Tao; Qu, Jing; Tang, Fuchou; Liu, Guang-Hui

    2015-01-01

    PTEN is a tumour suppressor frequently mutated in many types of cancers. Here we show that targeted disruption of PTEN leads to neoplastic transformation of human neural stem cells (NSCs), but not mesenchymal stem cells. PTEN-deficient NSCs display neoplasm-associated metabolic and gene expression profiles and generate intracranial tumours in immunodeficient mice. PTEN is localized to the nucleus in NSCs, binds to the PAX7 promoter through association with cAMP responsive element binding protein 1 (CREB)/CREB binding protein (CBP) and inhibits PAX7 transcription. PTEN deficiency leads to the upregulation of PAX7, which in turn promotes oncogenic transformation of NSCs and instates 'aggressiveness' in human glioblastoma stem cells. In a large clinical database, we find increased PAX7 levels in PTEN-deficient glioblastoma. Furthermore, we identify that mitomycin C selectively triggers apoptosis in NSCs with PTEN deficiency. Together, we uncover a potential mechanism of how PTEN safeguards NSCs, and establish a cellular platform to identify factors involved in NSC transformation, potentially permitting personalized treatment of glioblastoma. PMID:26632666

  13. Systematic analysis of the PTEN 5' leader identifies a major AUU initiated proteoform.

    PubMed

    Tzani, Ioanna; Ivanov, Ivaylo P; Andreev, Dmitri E; Dmitriev, Ruslan I; Dean, Kellie A; Baranov, Pavel V; Atkins, John F; Loughran, Gary

    2016-05-01

    Abundant evidence for translation within the 5' leaders of many human genes is rapidly emerging, especially, because of the advent of ribosome profiling. In most cases, it is believed that the act of translation rather than the encoded peptide is important. However, the wealth of available sequencing data in recent years allows phylogenetic detection of sequences within 5' leaders that have emerged under coding constraint and therefore allow for the prediction of functional 5' leader translation. Using this approach, we previously predicted a CUG-initiated, 173 amino acid N-terminal extension to the human tumour suppressor PTEN. Here, a systematic experimental analysis of translation events in the PTEN 5' leader identifies at least two additional non-AUG-initiated PTEN proteoforms that are expressed in most human cell lines tested. The most abundant extended PTEN proteoform initiates at a conserved AUU codon and extends the canonical AUG-initiated PTEN by 146 amino acids. All N-terminally extended PTEN proteoforms tested retain the ability to downregulate the PI3K pathway. We also provide evidence for the translation of two conserved AUG-initiated upstream open reading frames within the PTEN 5' leader that control the ratio of PTEN proteoforms.

  14. Systematic analysis of the PTEN 5′ leader identifies a major AUU initiated proteoform

    PubMed Central

    Tzani, Ioanna; Ivanov, Ivaylo P.; Andreev, Dmitri E.; Dmitriev, Ruslan I.; Dean, Kellie A.; Baranov, Pavel V.; Atkins, John F.; Loughran, Gary

    2016-01-01

    Abundant evidence for translation within the 5′ leaders of many human genes is rapidly emerging, especially, because of the advent of ribosome profiling. In most cases, it is believed that the act of translation rather than the encoded peptide is important. However, the wealth of available sequencing data in recent years allows phylogenetic detection of sequences within 5′ leaders that have emerged under coding constraint and therefore allow for the prediction of functional 5′ leader translation. Using this approach, we previously predicted a CUG-initiated, 173 amino acid N-terminal extension to the human tumour suppressor PTEN. Here, a systematic experimental analysis of translation events in the PTEN 5′ leader identifies at least two additional non-AUG-initiated PTEN proteoforms that are expressed in most human cell lines tested. The most abundant extended PTEN proteoform initiates at a conserved AUU codon and extends the canonical AUG-initiated PTEN by 146 amino acids. All N-terminally extended PTEN proteoforms tested retain the ability to downregulate the PI3K pathway. We also provide evidence for the translation of two conserved AUG-initiated upstream open reading frames within the PTEN 5′ leader that control the ratio of PTEN proteoforms. PMID:27249819

  15. PTEN deficiency reprogrammes human neural stem cells towards a glioblastoma stem cell-like phenotype.

    PubMed

    Duan, Shunlei; Yuan, Guohong; Liu, Xiaomeng; Ren, Ruotong; Li, Jingyi; Zhang, Weizhou; Wu, Jun; Xu, Xiuling; Fu, Lina; Li, Ying; Yang, Jiping; Zhang, Weiqi; Bai, Ruijun; Yi, Fei; Suzuki, Keiichiro; Gao, Hua; Esteban, Concepcion Rodriguez; Zhang, Chuanbao; Izpisua Belmonte, Juan Carlos; Chen, Zhiguo; Wang, Xiaomin; Jiang, Tao; Qu, Jing; Tang, Fuchou; Liu, Guang-Hui

    2015-12-03

    PTEN is a tumour suppressor frequently mutated in many types of cancers. Here we show that targeted disruption of PTEN leads to neoplastic transformation of human neural stem cells (NSCs), but not mesenchymal stem cells. PTEN-deficient NSCs display neoplasm-associated metabolic and gene expression profiles and generate intracranial tumours in immunodeficient mice. PTEN is localized to the nucleus in NSCs, binds to the PAX7 promoter through association with cAMP responsive element binding protein 1 (CREB)/CREB binding protein (CBP) and inhibits PAX7 transcription. PTEN deficiency leads to the upregulation of PAX7, which in turn promotes oncogenic transformation of NSCs and instates 'aggressiveness' in human glioblastoma stem cells. In a large clinical database, we find increased PAX7 levels in PTEN-deficient glioblastoma. Furthermore, we identify that mitomycin C selectively triggers apoptosis in NSCs with PTEN deficiency. Together, we uncover a potential mechanism of how PTEN safeguards NSCs, and establish a cellular platform to identify factors involved in NSC transformation, potentially permitting personalized treatment of glioblastoma.

  16. PTEN Depletion Decreases Disease Severity and Modestly Prolongs Survival in a Mouse Model of Spinal Muscular Atrophy

    PubMed Central

    Little, Daniel; Valori, Chiara F; Mutsaers, Chantal A; Bennett, Ellen J; Wyles, Matthew; Sharrack, Basil; Shaw, Pamela J; Gillingwater, Thomas H; Azzouz, Mimoun; Ning, Ke

    2015-01-01

    Spinal muscular atrophy (SMA) is the second most common genetic cause of death in childhood. However, no effective treatment is available to halt disease progression. SMA is caused by mutations in the survival motor neuron 1 (SMN1) gene. We previously reported that PTEN depletion leads to an increase in survival of SMN-deficient motor neurons. Here, we aimed to establish the impact of PTEN modulation in an SMA mouse model in vivo. Initial experiments using intramuscular delivery of adeno-associated vector serotype 6 (AAV6) expressing shRNA against PTEN in an established mouse model of severe SMA (SMNΔ7) demonstrated the ability to ameliorate the severity of neuromuscular junction pathology. Subsequently, we developed self-complementary AAV9 expressing siPTEN (scAAV9-siPTEN) to allow evaluation of the effect of systemic suppression of PTEN on the disease course of SMA in vivo. Treatment with a single injection of scAAV9-siPTEN at postnatal day 1 resulted in a modest threefold extension of the lifespan of SMNΔ7 mice, increasing mean survival to 30 days, compared to 10 days in untreated mice. Our data revealed that systemic PTEN depletion is an important disease modifier in SMNΔ7 mice, and therapies aimed at lowering PTEN expression may therefore offer a potential therapeutic strategy for SMA. PMID:25369768

  17. PTEN and PI3K/AKT in non-small-cell lung cancer.

    PubMed

    Pérez-Ramírez, Cristina; Cañadas-Garre, Marisa; Molina, Miguel Ángel; Faus-Dáder, María José; Calleja-Hernández, Miguel Ángel

    2015-11-01

    Non-small-cell lung cancer (NSCLC) is the leading cause of cancer deaths worldwide. In the last years, the identification of activating EGFR mutations, conferring increased sensitivity and disease response to tyrosine kinase inhibitors, has changed the prospect of NSCLC patients. The PTEN/PI3K/AKT pathway regulates multiple cellular functions, including cell growth, differentiation, proliferation, survival, motility, invasion and intracellular trafficking. Alterations in this pathway, mainly PTEN inactivation, have been associated with resistance to EGFR-tyrosine kinase inhibitor therapy and lower survival in NSCLC patients. In this review, we will briefly discuss the main PTEN/PI3K/AKT pathway alterations found in NSCLC, as well as the cell processes regulated by PTEN/PI3K/AKT leading to tumorigenesis.

  18. Altered gravity downregulates aquaporin-1 protein expression in choroid plexus.

    PubMed

    Masseguin, C; Corcoran, M; Carcenac, C; Daunton, N G; Güell, A; Verkman, A S; Gabrion, J

    2000-03-01

    Aquaporin-1 (AQP1) is a water channel expressed abundantly at the apical pole of choroidal epithelial cells. The protein expression was quantified by immunocytochemistry and confocal microscopy in adult rats adapted to altered gravity. AQP1 expression was decreased by 64% at the apical pole of choroidal cells in rats dissected 5.5-8 h after a 14-day spaceflight. AQP1 was significantly overexpressed in rats readapted for 2 days to Earth's gravity after an 11-day flight (48% overshoot, when compared with the value measured in control rats). In a ground-based model that simulates some effects of weightlessness and alters choroidal structures and functions, apical AQP1 expression was reduced by 44% in choroid plexus from rats suspended head down for 14 days and by 69% in rats suspended for 28 days. Apical AQP1 was rapidly enhanced in choroid plexus of rats dissected 6 h after a 14-day suspension (57% overshoot, in comparison with control rats) and restored to the control level when rats were dissected 2 days after the end of a 14-day suspension. Decreases in the apical expression of choroidal AQP1 were also noted in rats adapted to hypergravity in the NASA 24-ft centrifuge: AQP1 expression was reduced by 47% and 85% in rats adapted for 14 days to 2 G and 3 G, respectively. AQP1 is downregulated in the apical membrane of choroidal cells in response to altered gravity and is rapidly restored after readaptation to normal gravity. This suggests that water transport, which is partly involved in the choroidal production of cerebrospinal fluid, might be decreased during spaceflight and after chronic hypergravity.

  19. Genetic alteration and gene expression modulation during cancer progression

    PubMed Central

    Garnis, Cathie; Buys, Timon PH; Lam, Wan L

    2004-01-01

    Cancer progresses through a series of histopathological stages. Progression is thought to be driven by the accumulation of genetic alterations and consequently gene expression pattern changes. The identification of genes and pathways involved will not only enhance our understanding of the biology of this process, it will also provide new targets for early diagnosis and facilitate treatment design. Genomic approaches have proven to be effective in detecting chromosomal alterations and identifying genes disrupted in cancer. Gene expression profiling has led to the subclassification of tumors. In this article, we will describe the current technologies used in cancer gene discovery, the model systems used to validate the significance of the genes and pathways, and some of the genes and pathways implicated in the progression of preneoplastic and early stage cancer. PMID:15035667

  20. Regulation of the activity of the tumor suppressor PTEN by thioredoxin in Drosophila melanogaster

    SciTech Connect

    Song, Zuohe; Saghafi, Negin; Gokhale, Vijay; Brabant, Marc; Meuillet, Emmanuelle J. . E-mail: emeuillet@azcc.arizona.edu

    2007-04-01

    Human Thioredoxin-1 (hTrx-1) is a small redox protein with a molecular weight of 12 kDa that contains two cysteine residues found in its catalytic site. HTrx-1 plays an important role in cell growth, apoptosis, and cancer patient prognosis. Recently, we have demonstrated that hTrx-1 binds to the C2 domain of the human tumor suppressor, PTEN, in a redox dependent manner. This binding leads to the inhibition of PTEN lipid phosphatase activity in mammalian tissue culture systems. In this study, we show that over-expression of hTrx-1 in Drosophila melanogaster promotes cell growth and proliferation during eye development as measured by eye size and ommatidia size. Furthermore, hTrx-1 rescues the small eye phenotype induced by the over-expression of PTEN. We demonstrate that this rescue of the PTEN-induced eye size phenotype requires cysteine-218 in the C2 domain of PTEN. We also show that hTrx-1 over-expression results in increased Akt phosphorylation in fly head extracts supporting our observations that the hTrx-1-induced eye size increase results from the inhibition of PTEN activity. Our study confirms the redox regulation of PTEN through disulfide bond formation with the hTrx-1 in Drosophila and suggests conserved mechanisms for thioredoxins and their interactions with the phosphatidylinositol-3-kinase signaling pathway in humans and fruit flies.

  1. Metformin inhibits inflammatory response via AMPK-PTEN pathway in vascular smooth muscle cells

    SciTech Connect

    Kim, Sun Ae; Choi, Hyoung Chul

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer PTEN was induced by metformin and inhibited by compound C and AMPK siRNA. Black-Right-Pointing-Pointer Metformin suppressed TNF-{alpha}-induced COX-2 and iNOS mRNA expression. Black-Right-Pointing-Pointer Compound C and bpv (pic) increased iNOS and COX-2 protein expression. Black-Right-Pointing-Pointer NF-{kappa}B activation was restored by inhibiting AMPK and PTEN. Black-Right-Pointing-Pointer AMPK and PTEN regulated TNF-{alpha}-induced ROS production in VSMCs. -- Abstract: Atherosclerosis is a chronic inflammation of the coronary arteries. Vascular smooth muscle cells (VSMCs) stimulated by cytokines and chemokines accelerate the inflammatory response and migrate to the injured endothelium during the progression of atherosclerosis. Activation of AMP activated protein kinase (AMPK), a key sensor maintaining metabolic homeostasis, suppresses the inflammatory response. However, how AMPK regulates the inflammatory response is poorly understood. To identify the mechanism of this response, we focused on phosphatase and tensin homolog (PTEN), which is a negative regulator of inflammation. We investigated that activation of AMPK-induced PTEN expression and suppression of the inflammatory response through the AMPK-PTEN pathway in VSMCs. We treated with the well-known AMPK activator metformin to induce PTEN expression. PTEN was induced by metformin (2 mM) and inhibited by compound C (10 {mu}M) and AMPK siRNA. Tumor necrosis factor-alpha (TNF-{alpha}) was used to induce inflammation. The inflammatory response was confirmed by cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS) expression, and activation of nuclear factor (NF)-{kappa}B. Metformin suppressed COX-2 and iNOS mRNA and protein expression dose dependently. Treatment with compound C and bpv (pic) in the presence of metformin, iNOS and COX-2 protein expression increased. NF-{kappa}B activation decreased in response to metformin and was restored by inhibiting AMPK

  2. Upregulation of PTEN suppresses invasion in Tca8113 tongue cancer cells through repression of epithelial-mesenchymal transition (EMT).

    PubMed

    Xie, Siming; Lu, Zhiyuan; Lin, Yanzhu; Shen, Lijia; Yin, Cao

    2016-05-01

    We previously discovered that the expression of the tumor suppressor phosphatase and tensin homolog (PTEN) was downregulated in the majority patients with tongue squamous cell carcinoma (TSCC). The aim of this study was to investigate the role of PTEN overexpression in the regulation of epithelial-mesenchymal transition (EMT) of the tongue squamous carcinoma cell line Tca8113 as well as explore the underlying mechanism. GV230 (containing the PTEN gene) and empty vectors were transfected into Tca8113 cells. After stable transfection, the messenger RNA (mRNA) and protein levels of PTEN were validated using quantitative real-time PCR (qPCR) and Western blot analysis. The growth and cell cycle were analyzed using Cell Counting Kit-8 (CCK-8) and flow cytometry, respectively. The invasion ability was measured with a transwell assay. The effects of PTEN overexpression on EMT and Hedgehog signaling were assessed by comparing Tca8113-PTEN cells with control and negative control cell groups. We found that PTEN expression was significantly upregulated after transfection. Meanwhile, upregulated PTEN inhibited the proliferation and invasion of Tca8113 cells. In addition, we observed changes in the EMT- and Hedgehog-associated proteins. These data demonstrated that PTEN upregulation could reduce invasion by inhibiting the process of EMT in Tca8113 cells, which might be related to the Hedgehog signaling pathway.

  3. Activation of nuclear PTEN by inhibition of Notch signaling induces G2/M cell cycle arrest in gastric cancer.

    PubMed

    Kim, S-J; Lee, H-W; Baek, J-H; Cho, Y-H; Kang, H G; Jeong, J S; Song, J; Park, H-S; Chun, K-H

    2016-01-14

    Mutation in PTEN has not yet been detected, but its function as a tumor suppressor is inactivated in many cancers. In this study we determined that, activated Notch signaling disables PTEN by phosphorylation and thereby contributes to gastric tumorigenesis. Notch inhibition by small interfering RNA or γ-secretase inhibitor (GSI) induced mitotic arrest and apoptosis in gastric cancer cells. Notch inhibition induced dephosphorylation in the C-terminal domain of PTEN, which led to PTEN nuclear localization. Overexpression of activated Notch1-induced phosphorylation of PTEN and reversed GSI-induced mitotic arrest. Dephosphorylated nuclear PTEN caused prometaphase arrest by interaction with the cyclin B1-CDK1 complex, resulting in their accumulation in the nucleus and subsequent apoptosis. We found a correlation between high expression levels of Notch1 and low survival rates and, similarly, between reduced nuclear PTEN expression and increasing the TNM classification of malignant tumours stages in malignant tissues from gastric cancer patients. The growth of Notch1-depleted gastric tumors was significantly retarded in xenografted mice, and in addition, PTEN deletion restored growth similar to control tumors. We also demonstrated that combination treatment with GSI and chemotherapeutic agents significantly reduced the orthotopically transplanted gastric tumors in mice without noticeable toxicity. Overall, our findings suggest that inhibition of Notch signaling can be employed as a PTEN activator, making it a potential target for gastric cancer therapy.

  4. Upregulation of PTEN suppresses invasion in Tca8113 tongue cancer cells through repression of epithelial-mesenchymal transition (EMT).

    PubMed

    Xie, Siming; Lu, Zhiyuan; Lin, Yanzhu; Shen, Lijia; Yin, Cao

    2016-05-01

    We previously discovered that the expression of the tumor suppressor phosphatase and tensin homolog (PTEN) was downregulated in the majority patients with tongue squamous cell carcinoma (TSCC). The aim of this study was to investigate the role of PTEN overexpression in the regulation of epithelial-mesenchymal transition (EMT) of the tongue squamous carcinoma cell line Tca8113 as well as explore the underlying mechanism. GV230 (containing the PTEN gene) and empty vectors were transfected into Tca8113 cells. After stable transfection, the messenger RNA (mRNA) and protein levels of PTEN were validated using quantitative real-time PCR (qPCR) and Western blot analysis. The growth and cell cycle were analyzed using Cell Counting Kit-8 (CCK-8) and flow cytometry, respectively. The invasion ability was measured with a transwell assay. The effects of PTEN overexpression on EMT and Hedgehog signaling were assessed by comparing Tca8113-PTEN cells with control and negative control cell groups. We found that PTEN expression was significantly upregulated after transfection. Meanwhile, upregulated PTEN inhibited the proliferation and invasion of Tca8113 cells. In addition, we observed changes in the EMT- and Hedgehog-associated proteins. These data demonstrated that PTEN upregulation could reduce invasion by inhibiting the process of EMT in Tca8113 cells, which might be related to the Hedgehog signaling pathway. PMID:26649861

  5. Long-term consequences of conditional genetic deletion of PTEN in the sensorimotor cortex of neonatal mice.

    PubMed

    Gutilla, Erin A; Buyukozturk, Melda M; Steward, Oswald

    2016-05-01

    Targeted deletion of the phosphatase and tensin homolog on chromosome ten (PTEN) gene in the sensorimotor cortex of neonatal mice enables robust regeneration of corticospinal tract (CST) axons following spinal cord injury as adults. Here, we assess the consequences of long-term conditional genetic PTEN deletion on cortical structure and neuronal morphology and screen for neuropathology. Mice with a LoxP-flanked exon 5 of the PTEN gene (PTENf/f mice) received AAV-Cre injections into the sensorimotor cortex at postnatal day 1 (P1) and were allowed to survive for up to 18months. As adults, mice were assessed for exploratory activity (open field), and motor coordination using the Rotarod®. Some mice received injections of Fluorogold into the spinal cord to retrogradely label the cells of origin of the CST. Brains were prepared for neurohistology and immunostained for PTEN and phospho-S6, which is a downstream marker of mammalian target of rapamycin (mTOR) activation. Immunostaining revealed a focal area of PTEN deletion affecting neurons in all cortical layers, although in some cases PTEN expression was maintained in many small-medium sized neurons in layers III-IV. Neurons lacking PTEN were robustly stained for pS6. Cortical thickness was significantly increased and cortical lamination was disrupted in the area of PTEN deletion. PTEN-negative layer V neurons that give rise to the CST, identified by retrograde labeling, were larger than neurons with maintained PTEN expression, and the relative area occupied by neuropil vs. cell bodies was increased. There was no evidence of tumor formation or other neuropathology. Mice with PTEN deletion exhibited open field activity comparable to controls and there was a trend for impaired Rotarod performance (not statistically significant). Our findings indicate that early postnatal genetic deletion of PTEN that is sufficient to enable axon regeneration by adult neurons causes neuronal hypertrophy but no other detectable

  6. A Critical Role of the PTEN/PDGF Signaling Network for the Regulation of Radiosensitivity in Adenocarcinoma of the Prostate

    SciTech Connect

    Christensen, Michael; Najy, Abdo J.; Snyder, Michael; Movilla, Lisa S.; Kim, Hyeong-Reh Choi

    2014-01-01

    Purpose: Loss or mutation of the phosphate and tensin homologue (PTEN) is a common genetic abnormality in prostate cancer (PCa) and induces platelet-derived growth factor D (PDGF D) signaling. We examined the role of the PTEN/PDGF axis on radioresponse using a murine PTEN null prostate epithelial cell model. Methods and Materials: PTEN wild-type (PTEN{sup +/+}) and PTEN knockout (PTEN{sup −/−}) murine prostate epithelial cell lines were used to examine the relationship between the PTEN status and radiosensitivity and also to modulate the PDGF D expression levels. PTEN{sup −/−} cells were transduced with a small hairpin RNA (shRNA) lentiviral vector containing either scrambled nucleotides (SCRM) or sequences targeted to PDGF D (shPDGF D). Tumorigenesis and morphogenesis of these cell lines were evaluated in vivo via subcutaneous injection of male nude mice and in vitro using Matrigel 3-dimensional (3D) culture. Effects of irradiation on clonogenic survival, cell migration, and invasion were measured with respect to the PTEN status and the PDGF D expression level. In addition, apoptosis and cell cycle redistribution were examined as potential mechanisms for differences seen. Results: PTEN{sup −/−} cells were highly tumorigenic in animals and effectively formed foci in 3D culture. Importantly, loss of PDGF D in these cell lines drastically diminished these phenotypes. Furthermore, PTEN{sup −/−} cells demonstrated increased clonogenic survival in vitro compared to PTEN{sup +/+}, and attenuation of PDGF D significantly reversed this radioresistant phenotype. PTEN{sup −/−} cells displayed greater migratory and invasive potential at baseline as well as after irradiation. Both the basal and radiation-induced migratory and invasive phenotypes in PTEN{sup −/−} cells required PDGF D expression. Interestingly, these differences were independent of apoptosis and cell cycle redistribution, as they showed no significant difference. Conclusions: We propose

  7. Suppression of cellular proliferation and invasion by the concerted lipid and protein phosphatase activities of PTEN

    PubMed Central

    Davidson, Lindsay; Maccario, Helene; Perera, Nevin M.; Yang, Xuesong; Spinelli, Laura; Tibarewal, Priyanka; Glancy, Ben; Gray, Alex; Weijer, Cornelis J.; Downes, C. Peter; Leslie, Nick R.

    2009-01-01

    PTEN is a tumour suppressor with phosphatase activity in vitro against both lipids and proteins and other potential non-enzymatic mechanisms of action. Although the importance of PTEN’s lipid phosphatase activity in regulating the PI3K signalling pathway is recognised, the significance of PTEN’s other mechanisms of action is currently unclear. Here, we describe the systematic identification of a PTEN mutant, PTEN Y138L, with activity against lipid, but not soluble substrates. Using this mutant we provide evidence for the interfacial activation of PTEN against lipid substrates. We also show that when re-expressed at physiological levels in PTEN null U87MG glioblastoma cells the protein phosphatase activity of PTEN is not required to regulate cellular PtdInsP3 levels or the downstream protein kinase Akt/PKB. Finally, in 3D Matrigel cultures of U87MG cells similarly re-expressing PTEN mutants, both the protein and lipid phosphatase activities were required to inhibit invasion, but either activity alone significantly inhibited proliferation, albeit only weakly for the protein phosphatase activity. Our data provides a novel tool to address the significance of PTEN’s separable lipid and protein phosphatase activities and suggest that both activities act to suppress proliferation and act together to suppress invasion. PMID:19915616

  8. Altered choroid plexus gene expression in major depressive disorder

    PubMed Central

    Turner, Cortney A.; Thompson, Robert C.; Bunney, William E.; Schatzberg, Alan F.; Barchas, Jack D.; Myers, Richard M.; Akil, Huda; Watson, Stanley J.

    2014-01-01

    Given the emergent interest in biomarkers for mood disorders, we assessed gene expression in the choroid plexus (CP), the region that produces cerebrospinal fluid (CSF), in individuals with major depressive disorder (MDD). Genes that are expressed in the CP can be secreted into the CSF and may be potential biomarker candidates. Given that we have previously shown that fibroblast growth factor family members are differentially expressed in post-mortem brain of subjects with MDD and the CP is a known source of growth factors in the brain, we posed the question whether growth factor dysregulation would be found in the CP of subjects with MDD. We performed laser capture microscopy of the CP at the level of the hippocampus in subjects with MDD and psychiatrically normal controls. We then extracted, amplified, labeled, and hybridized the cRNA to Illumina BeadChips to assess gene expression. In controls, the most highly abundant known transcript was transthyretin. Moreover, half of the 14 most highly expressed transcripts in controls encode ribosomal proteins. Using BeadStudio software, we identified 169 transcripts differentially expressed (p < 0.05) between control and MDD samples. Using pathway analysis we noted that the top network altered in subjects with MDD included multiple members of the transforming growth factor-beta (TGFβ) pathway. Quantitative real-time PCR (qRT-PCR) confirmed downregulation of several transcripts that interact with the extracellular matrix in subjects with MDD. These results suggest that there may be an altered cytoskeleton in the CP in MDD subjects that may lead to a disrupted blood-CSF-brain barrier. PMID:24795602

  9. Altered MENIN expression disrupts the MAFA differentiation pathway in insulinoma.

    PubMed

    Hamze, Z; Vercherat, C; Bernigaud-Lacheretz, A; Bazzi, W; Bonnavion, R; Lu, J; Calender, A; Pouponnot, C; Bertolino, P; Roche, C; Stein, R; Scoazec, J Y; Zhang, C X; Cordier-Bussat, M

    2013-12-01

    The protein MENIN is the product of the multiple endocrine neoplasia type I (MEN1) gene. Altered MENIN expression is one of the few events that are clearly associated with foregut neuroendocrine tumours (NETs), classical oncogenes or tumour suppressors being not involved. One of the current challenges is to understand how alteration of MENIN expression contributes to the development of these tumours. We hypothesised that MENIN might regulate factors maintaining endocrine-differentiated functions. We chose the insulinoma model, a paradigmatic example of well-differentiated pancreatic NETs, to study whether MENIN interferes with the expression of v-MAF musculoaponeurotic fibrosarcoma oncogene homologue A (MAFA), a master glucose-dependent transcription factor in differentiated β-cells. Immunohistochemical analysis of a series of human insulinomas revealed a correlated decrease in both MENIN and MAFA. Decreased MAFA expression resulting from targeted Men1 ablation was also consistently observed in mouse insulinomas. In vitro analyses using insulinoma cell lines showed that MENIN regulated MAFA protein and mRNA levels, and bound to Mafa promoter sequences. MENIN knockdown concomitantly decreased mRNA expression of both Mafa and β-cell differentiation markers (Ins1/2, Gck, Slc2a2 and Pdx1) and, in parallel, increased the proliferation rate of tumours as measured by bromodeoxyuridine incorporation. Interestingly, MAFA knockdown alone also increased proliferation rate but did not affect the expression of candidate proliferation genes regulated by MENIN. Finally, MENIN variants with missense mutations detected in patients with MEN1 lost the WT MENIN properties to regulate MAFA. Together, our findings unveil a previously unsuspected MENIN/MAFA connection regarding control of the β-cell differentiation/proliferation balance, which could contribute to tumorigenesis.

  10. Altered gene expression in conjunctival squamous cell carcinoma.

    PubMed

    Mahale, Alka; Alkatan, Hind; Alwadani, Saeed; Othman, Maha; Suarez, Maria J; Price, Antoinette; Al-Hussain, Hailah; Jastaneiah, Sabah; Yu, Wayne; Maktabi, Azza; Deepak, Edward P; Eberhart, Charles G; Asnaghi, Laura

    2016-05-01

    Conjunctival squamous cell carcinoma is a malignancy of the ocular surface. The molecular drivers responsible for the development and progression of this disease are not well understood. We therefore compared the transcriptional profiles of eight snap-frozen conjunctival squamous cell carcinomas and one in situ lesion with normal conjunctival specimens in order to identify diagnostic markers or therapeutic targets. RNA was analyzed using oligonucleotide microarrays, and a wide range of transcripts with altered expression identified, including many dysregulated in carcinomas arising at other sites. Among the upregulated genes, we observed more than 30-fold induction of the matrix metalloproteinases, MMP-9 and MMP-11, as well as a prominent increase in the mRNA level of a calcium-binding protein important for the intracellular calcium signaling, S100A2, which was induced over 20-fold in the tumor cohort. Clusterin was the most downregulated gene, with an approximately 180-fold reduction in the mRNA expression. These alterations were all confirmed by qPCR in the samples used for initial microarray analysis. In addition, immunohistochemical analysis confirmed the overexpression of MMP-11 and S100A2, as well as reductions in clusterin, in several independent in situ carcinomas of conjunctiva. These data identify a number of alterations, including upregulation of MMP-9, MMP-11, and S100A2, as well as downregulation of clusterin, associated with epithelial tumorigenesis in the ocular surface. PMID:26916071

  11. Plk1 Protein Phosphorylates Phosphatase and Tensin Homolog (PTEN) and Regulates Its Mitotic Activity during the Cell Cycle*

    PubMed Central

    Choi, Byeong Hyeok; Pagano, Michele; Dai, Wei

    2014-01-01

    PTEN is a well known tumor suppressor through the negative regulation of the PI3K signaling pathway. Here we report that PTEN plays an important role in regulating mitotic timing, which is associated with increased PTEN phosphorylation in the C-terminal tail and its localization to chromatin. Pulldown analysis revealed that Plk1 physically interacted with PTEN. Biochemical studies showed that Plk1 phosphorylates PTEN in vitro in a concentration-dependent manner and that the phosphorylation was inhibited by Bi2635, a Plk1-specific inhibitor. Deletional and mutational analyses identified that Plk1 phosphorylated Ser-380, Thr-382, and Thr-383, but not Ser-385, a cluster of residues known to affect the PTEN stability. Interestingly, a combination of molecular and genetic analyses revealed that only Ser-380 was significantly phosphorylated in vivo and that Plk1 regulated the phosphorylation, which was associated with the accumulation of PTEN on chromatin. Moreover, expression of phospho-deficient mutant, but not wild-type PTEN, caused enhanced mitotic exit. Taken together, our studies identify Plk1 as an important regulator of PTEN during the cell cycle. PMID:24706748

  12. Methylphenidate alters NCS-1 expression in rat brain.

    PubMed

    Souza, Renan P; Soares, Eliane C; Rosa, Daniela V F; Souza, Bruno R; Réus, Gislaine Z; Barichello, Tatiana; Gomes, Karin M; Gomez, Marcus V; Quevedo, João; Romano-Silva, Marco A

    2008-07-01

    Methylphenidate has been used as an effective treatment for attention deficit hyperactivity disorder (ADHD). Methylphenidate (MPH) blocks dopamine and norepinephrine transporters causing an increase in extracellular levels. The use of psychomotor stimulants continues to rise due to both the treatment of ADHD and illicit abuse. Methylphenidate sensitization mechanism has still poor knowledge. Neuronal calcium sensor 1 was identified as a dopaminergic receptor interacting protein. When expressed in mammalian cells, neuronal calcium sensor 1 attenuates dopamine-induced D2 receptor internalization by a mechanism that involves a reduction in D2 receptor phosphorylation. Neuronal calcium sensor 1 appears to play a pivotal role in regulating D2 receptor function, it will be important to determine if there are alterations in neuronal calcium sensor 1 in neuropathologies associated with deregulation in dopaminergic signaling. Then, we investigated if methylphenidate could alter neuronal calcium sensor 1 expression in five brain regions (striatum, hippocampus, prefrontal cortex, cortex and cerebellum) in young and adult rats. These regions were chosen because some are located in brain circuits related with attention deficit hyperactivity disorder. Our results showed changes in neuronal calcium sensor 1 expression in hippocampus, prefrontal cortex and cerebellum mainly in adult rats. The demonstration that methylphenidate induces changes in neuronal calcium sensor 1 levels in rat brain may help to understand sensitization mechanisms as well as methylphenidate therapeutic effects to improve attention deficit hyperactivity disorder symptoms.

  13. Glioma cell VEGFR-2 confers resistance to chemotherapeutic and antiangiogenic treatments in PTEN-deficient glioblastoma.

    PubMed

    Kessler, Tobias; Sahm, Felix; Blaes, Jonas; Osswald, Matthias; Rübmann, Petra; Milford, David; Urban, Severino; Jestaedt, Leonie; Heiland, Sabine; Bendszus, Martin; Hertenstein, Anne; Pfenning, Philipp-Niclas; Ruiz de Almodóvar, Carmen; Wick, Antje; Winkler, Frank; von Deimling, Andreas; Platten, Michael; Wick, Wolfgang; Weiler, Markus

    2015-10-13

    Loss of the tumor suppressor phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a prerequisite for tumor cell-specific expression of vascular endothelial growth factor receptor (VEGFR)-2 in glioblastoma defining a subgroup prone to develop evasive resistance towards antiangiogenic treatments. Immunohistochemical analysis of human tumor tissues showed VEGFR-2 expression in glioma cells in 19% of specimens examined, mainly in the infiltration zone. Glioma cell VEGFR-2 positivity was restricted to PTEN-deficient tumor specimens. PTEN overexpression reduced VEGFR-2 expression in vitro, as well as knock-down of raptor or rictor. Genetic interference with VEGFR-2 revealed proproliferative, antiinvasive and chemoprotective functions for VEGFR-2 in glioma cells. VEGFR-2-dependent cellular effects were concomitant with activation of 'kappa-light-chain-enhancer' of activated B-cells, protein kinase B, and N-myc downstream regulated gene 1. Two-photon in vivo microscopy revealed that expression of VEGFR-2 in glioma cells hampers antiangiogenesis. Bevacizumab induces a proinvasive response in VEGFR-2-positive glioma cells. Patients with PTEN-negative glioblastomas had a shorter survival after initiation of bevacizumab therapy compared with PTEN-positive glioblastomas. Conclusively, expression of VEGFR-2 in glioma cells indicates an aggressive glioblastoma subgroup developing early resistance to temozolomide or bevacizumab. Loss of PTEN may serve as a biomarker identifying those tumors upfront by routine neuropathological methods.

  14. Expression alterations define unique molecular characteristics of spinal ependymomas

    PubMed Central

    Lourdusamy, Anbarasu; Rahman, Ruman; Grundy, Richard G.

    2015-01-01

    Ependymomas are glial tumors that originate in either intracranial or spinal regions. Although tumors from different regions are histologically similar, they are biologically distinct. We therefore sought to identify molecular characteristics of spinal ependymomas (SEPN) in order to better understand the disease biology of these tumors. Using gene expression profiles of 256 tumor samples, we identified increased expression of 1,866 genes in SEPN when compared to intracranial ependymomas. These genes are mainly related to anterior/posterior pattern specification, response to oxidative stress, glial cell differentiation, DNA repair, and PPAR signalling, and also significantly enriched with cellular senescence genes (P = 5.5 × 10−03). In addition, a high number of significantly down-regulated genes in SEPN are localized to chromosome 22 (81 genes from chr22: 43,325,255 – 135,720,974; FDR = 1.77 × 10−23 and 22 genes from chr22: 324,739 – 32,822,302; FDR = 2.07 × 10−09) including BRD1, EP300, HDAC10, HIRA, HIC2, MKL1, and NF2. Evaluation of NF2 co-expressed genes further confirms the enrichment of chromosome 22 regions. Finally, systematic integration of chromosome 22 genes with interactome and NF2 co-expression data identifies key candidate genes. Our results reveal unique molecular characteristics of SEPN such as altered expression of cellular senescence and chromosome 22 genes. PMID:25909290

  15. Protean PTEN: Form and Function

    PubMed Central

    Waite, Kristin A.; Eng, Charis

    2002-01-01

    Germline mutations distributed across the PTEN tumor-suppressor gene have been found to result in a wide spectrum of phenotypic features. Originally shown to be a major susceptibility gene for both Cowden syndrome (CS), which is characterized by multiple hamartomas and an increased risk of breast, thyroid, and endometrial cancers, and Bannayan-Riley-Ruvalcaba syndrome, which is characterized by lipomatosis, macrocephaly, and speckled penis, the PTEN hamartoma tumor syndrome spectrum has broadened to include Proteus syndrome and Proteus-like syndromes. Exon 5, which encodes the core motif, is a hotspot for mutations likely due to the biology of the protein. PTEN is a major lipid 3-phosphatase, which signals down the PI3 kinase/AKT pro-apoptotic pathway. Furthermore, PTEN is a protein phosphatase, with the ability to dephosphorylate both serine and threonine residues. The protein-phosphatase activity has also been shown to regulate various cell-survival pathways, such as the mitogen-activated kinase (MAPK) pathway. Although it is well established that PTEN’s lipid-phosphatase activity, via the PI3K/AKT pathway, mediates growth suppression, there is accumulating evidence that the protein-phosphatase/MAPK pathway is equally important in the mediation of growth arrest and other crucial cellular functions. PMID:11875759

  16. Mitochondrial Dysfunction in Pten Haplo-Insufficient Mice with Social Deficits and Repetitive Behavior: Interplay between Pten and p53

    PubMed Central

    Napoli, Eleonora; Ross-Inta, Catherine; Wong, Sarah; Hung, Connie; Fujisawa, Yasuko; Sakaguchi, Danielle; Angelastro, James; Omanska-Klusek, Alicja; Schoenfeld, Robert; Giulivi, Cecilia

    2012-01-01

    Etiology of aberrant social behavior consistently points to a strong polygenetic component involved in fundamental developmental pathways, with the potential of being enhanced by defects in bioenergetics. To this end, the occurrence of social deficits and mitochondrial outcomes were evaluated in conditional Pten (Phosphatase and tensin homolog) haplo-insufficient mice, in which only one allele was selectively knocked-out in neural tissues. Pten mutations have been linked to Alzheimer's disease and syndromic autism spectrum disorders, among others. By 4–6 weeks of age, Pten insufficiency resulted in the increase of several mitochondrial Complex activities (II–III, IV and V) not accompanied by increases in mitochondrial mass, consistent with an activation of the PI3K/Akt pathway, of which Pten is a negative modulator. At 8–13 weeks of age, Pten haplo-insufficient mice did not show significant behavioral abnormalities or changes in mitochondrial outcomes, but by 20–29 weeks, they displayed aberrant social behavior (social avoidance, failure to recognize familiar mouse, and repetitive self-grooming), macrocephaly, increased oxidative stress, decreased cytochrome c oxidase (CCO) activity (50%) and increased mtDNA deletions in cerebellum and hippocampus. Mitochondrial dysfunction was the result of a downregulation of p53-signaling pathway evaluated by lower protein expression of p21 (65% of controls) and the CCO chaperone SCO2 (47% of controls), two p53-downstream targets. This mechanism was confirmed in Pten-deficient striatal neurons and, HCT 116 cells with different p53 gene dosage. These results suggest a unique pathogenic mechanism of the Pten-p53 axis in mice with aberrant social behavior: loss of Pten (via p53) impairs mitochondrial function elicited by an early defective assembly of CCO and later enhanced by the accumulation of mtDNA deletions. Consistent with our results, (i) SCO2 deficiency and/or CCO activity defects have been reported in patients with

  17. Mice Lacking Pten in Osteoblasts Have Improved Intramembranous and Late Endochondral Fracture Healing

    PubMed Central

    Burgers, Travis A.; Hoffmann, Martin F.; Collins, Caitlyn J.; Zahatnansky, Juraj; Alvarado, Martin A.; Morris, Michael R.; Sietsema, Debra L.; Mason, James J.; Jones, Clifford B.; Ploeg, Heidi L.; Williams, Bart O.

    2013-01-01

    The failure of an osseous fracture to heal (development of a non-union) is a common and debilitating clinical problem. Mice lacking the tumor suppressor Pten in osteoblasts have dramatic and progressive increases in bone volume and density throughout life. Since fracture healing is a recapitulation of bone development, we investigated the process of fracture healing in mice lacking Pten in osteoblasts (Ocn-cretg/+;Ptenflox/flox). Mid-diaphyseal femoral fractures induced in wild-type and Ocn-cretg/+;Ptenflox/flox mice were studied via micro-computed tomography (µCT) scans, biomechanical testing, histological and histomorphometric analysis, and protein expression analysis. Ocn-cretg/+;Ptenflox/flox mice had significantly stiffer and stronger intact bones relative to controls in all cohorts. They also had significantly stiffer healing bones at day 28 post-fracture (PF) and significantly stronger healing bones at days 14, 21, and 28 PF. At day 7 PF, the proximal and distal ends of the Pten mutant calluses were more ossified. By day 28 PF, Pten mutants had larger and more mineralized calluses. Pten mutants had improved intramembranous bone formation during healing originating from the periosteum. They also had improved endochondral bone formation later in the healing process, after mature osteoblasts are present in the callus. Our results indicate that the inhibition of Pten can improve fracture healing and that the local or short-term use of commercially available Pten-inhibiting agents may have clinical application for enhancing fracture healing. PMID:23675511

  18. Mitochondria-related miR-141-3p contributes to mitochondrial dysfunction in HFD-induced obesity by inhibiting PTEN.

    PubMed

    Ji, Juan; Qin, Yufeng; Ren, Jing; Lu, Chuncheng; Wang, Rong; Dai, Xiuliang; Zhou, Ran; Huang, Zhenyao; Xu, Miaofei; Chen, Minjian; Wu, Wei; Song, Ling; Shen, Hongbing; Hu, Zhibin; Miao, Dengshun; Xia, Yankai; Wang, Xinru

    2015-11-09

    Mitochondria-related microRNAs (miRNAs) have recently emerged as key regulators of cell metabolism and can modulate mitochondrial fusion and division. In order to investigate the roles of mitochondria-related miRNAs played in obesity, we conducted comprehensive molecular analysis in vitro and in vivo. Based on high-fat-diet (HFD) induced obese mice, we found that hepatic mitochondrial function was markedly altered. Subsequently, we evaluated the expression levels of selected mitochondria-related miRNAs and found that miR-141-3p was up-regulated strikingly in HFD mice. To further verify the role of miR-141-3p in obesity, we carried out gain-and-loss-of-function study in human HepG2 cells. We found that miR-141-3p could modulate ATP production and induce oxidative stress. Through luciferase report gene assay, we identified that phosphatase and tensin homolog (PTEN) was a target of miR-141-3p. Inhibiting PTEN could alter the mitochondrial function, too. Our study suggested that mitochondria-related miR-141-3p induced mitochondrial dysfunction by inhibiting PTEN.

  19. Radiation Exposure Alters Expression of Metabolic Enzyme Genes In Mice

    NASA Technical Reports Server (NTRS)

    Wotring, Virginia E.; Mangala, L. S.; Zhang, Y.; Wu, H.

    2010-01-01

    Most pharmaceuticals are metabolized by the liver. The health of the liver, especially the rate of its metabolic enzymes, determines the concentration of circulating drugs as well as the duration of their efficacy. Because of the importance of the liver in drug metabolism it is important to understand the effects of spaceflight on the enzymes of the liver. Exposure to cosmic radiation is one aspect of spaceflight that can be modeled in ground experiments. This study is an effort to examine the effects of adaptive mechanisms that may be triggered by early exposure to low radiation doses. Using procedures approved by the JSC Animal Care & Use Committee, C57 male mice were exposed to Cs-137 in groups: controls, low dose (50 mGy), high dose (6Gy) and a fourth group that received both radiation doses separated by 24 hours. Animals were anesthetized and sacrificed 4 hours after their last radiation exposure. Livers were removed immediately and flash-frozen in liquid nitrogen. Tissue was homogenized, RNA extracted and purified (Absolutely RNA, Agilent). Quality of RNA samples was evaluated (Agilent Bioanalyzer 2100). Complementary DNA was prepared from high-quality RNA samples, and used to run RT-qPCR screening arrays for DNA Repair and Drug Metabolism (SuperArray, SABiosciences/Qiagen; BioRad Cfx96 qPCR System). Of 91 drug metabolism genes examined, expression of 7 was altered by at least one treatment condition. Genes that had elevated expression include those that metabolize promethazine and steroids (4-8-fold), many that reduce oxidation products, and one that reduces heavy metal exposure (greater than 200-fold). Of the 91 DNA repair and general metabolism genes examined, expression of 14 was altered by at least one treatment condition. These gene expression changes are likely homeostatic and could lead to development of new radioprotective countermeasures.

  20. Rb1 and Pten Co-Deletion in Osteoblast Precursor Cells Causes Rapid Lipoma Formation in Mice

    PubMed Central

    Filtz, Emma A.; Emery, Ann; Lu, Huarui; Forster, Colleen L.; Karasch, Chris; Hallstrom, Timothy C.

    2015-01-01

    The Rb and Pten tumor suppressor genes are important regulators of bone development and both are frequently mutated in the bone cancer osteosarcoma (OS). To determine if Rb1 and Pten synergize as tumor suppressor genes for osteosarcoma, we co-deleted them in osteoprogenitor cells. Surprisingly, we observed rapid development of adipogenic but not osteosarcoma tumors in the ΔRb1/Pten mice. ΔPten solo deleted mice also developed lipoma tumors but at a much reduced frequency and later onset than those co-deleted for Rb1. Pten deletion also led to a marked increase in adipocytes in the bone marrow. To better understand the function of Pten in bone development in vivo, we conditionally deleted Pten in OSX+ osteoprogenitor cells using OSX-Cre mice. μCT analysis revealed a significant thickening of the calvaria and an increase in trabeculae volume and number in the femur, consistent with increased bone formation in these mice. To determine if Pten and Rb1 deletion actively promotes adipogenic differentiation, we isolated calvarial cells from Ptenfl/fl and Ptenfl/fl; Rb1fl/fl mice, infected them with CRE or GFP expressing adenovirus, treated with differentiation media. We observed slightly increased adipogenic, and osteogenic differentiation in the ΔPten cells. Both phenotypes were greatly increased upon Rb1/Pten co-deletion. This was accompanied by an increase in expression of genes required for adipogenesis. These data indicate that Pten deletion in osteoblast precursors is sufficient to promote frequent adipogenic, but only rare osteogenic tumors. Rb1 hetero- or homo-zygous co-deletion greatly increases the incidence and the rapidity of onset of adipogenic tumors, again, with only rare osteosarcoma tumors. PMID:26317218

  1. In vitro maturation alters gene expression in bovine oocytes.

    PubMed

    Adona, Paulo R; Leal, Cláudia L V; Biase, Fernando H; De Bem, Tiago H; Mesquita, Lígia G; Meirelles, Flávio V; Ferraz, André L; Furlan, Luiz R; Monzani, Paulo S; Guemra, Samuel

    2016-08-01

    Gene expression profiling of in vivo- and in vitro-matured bovine oocytes can identify transcripts related to the developmental potential of oocytes. Nonetheless, the effects of in vitro culturing oocytes are yet to be fully understood. We tested the effects of in vitro maturation on the transcript profile of oocytes collected from Bos taurus indicus cows. We quantified the expression of 1488 genes in in vivo- and in vitro-matured oocytes. Of these, 51 genes were up-regulated, whereas 56 were down-regulated (≥2-fold) in in vivo-matured oocytes in comparison with in vitro-matured oocytes. Quantitative real-time polymerase chain reaction (PCR) of nine genes confirmed the microarray results of differential expression between in vivo- and in vitro-matured oocytes (EZR, EPN1, PSEN2, FST, IGFBP3, RBBP4, STAT3, FDPS and IRS1). We interrogated the results for enrichment of Gene Ontology categories and overlap with protein-protein interactions. The results revealed that the genes altered by in vitro maturation are mostly related to the regulation of oocyte metabolism. Additionally, analysis of protein-protein interactions uncovered two regulatory networks affected by the in vitro culture system. We propose that the differentially expressed genes are candidates for biomarkers of oocyte competence. In vitro oocyte maturation can affect the abundance of specific transcripts and are likely to deplete the developmental competence.

  2. HIV-associated mucosal gene expression: region-specific alterations

    PubMed Central

    Voigt, Robin M.; Keshavarzian, Ali; Losurdo, John; Swanson, Garth; Siewe, Basile; Forsyth, Christopher B.; French, Audrey L.; Demarais, Patricia; Engen, Phillip; Raeisi, Shohreh; Mutlu, Ece; Landay, Alan L.

    2016-01-01

    Objective Despite the use of HAART to control HIV, systemic immune activation and inflammation persists with the consequence of developing serious non-AIDS events. The mechanisms that contribute to persistent systemic immune activation have not been well defined. The intestine is the major source of “sterile” inflammation and plays a critical role in immune function; thus, we sought to determine whether intestinal gene expression was altered in virally controlled HIV-infected individuals. Design and methods Gene expression was compared in biopsy samples collected from HIV-uninfected and HIV-infected individuals from the ileum, right colon (ascending colon), and left colon (sigmoid). Affymetrix gene arrays were performed on tissues and pathway analyses were conducted. Gene expression was correlated with systemic markers of intestinal barrier dysfunction and inflammation and intestinal microbiota composition. Results Genes involved in cellular immune response, cytokine signaling, pathogen-influenced signaling, humoral immune response, apoptosis, intracellular and second messenger signaling, cancer, organismal growth and development, and proliferation and development were upregulated in the intestine of HIV-infected individuals with differences observed in the ileum, right, and left colon. Gene expression in the ileum primarily correlated with systemic markers of inflammation (e.g., IL7R, IL2, and TLR2 with serum TNF) whereas expression in the colon correlated with the microbiota community (e.g., IFNG, IL1B, and CD3G with Bacteroides). Conclusion These data demonstrate persistent, proinflammatory changes in the intestinal mucosa of virally suppressed HIV-infected individuals. These changes in intestinal gene expression may be the consequence of or contribute to barrier dysfunction and intestinal dysbiosis observed in HIV. PMID:25587909

  3. Suppression of Akt1 phosphorylation by adenoviral transfer of the PTEN gene inhibits hypoxia-induced proliferation of rat pulmonary arterial smooth muscle cells

    SciTech Connect

    Luo, Chunxia; Yi, Bin; Bai, Li; Xia, Yongzhi; Wang, Guansong; Qian, Guisheng; Feng, Hua

    2010-07-02

    Recent findings identify the role of proliferation of pulmonary artery smooth muscle cells (PASMCs) in pulmonary vascular remodeling. Phosphoinositide 3 kinase (PI3K) and serine/threonine kinase (Akt) proteins are expressed in vascular smooth muscle cells. In addition, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) has been identified as a negative regulator of cytokine signaling that inhibits the PI3K-Akt pathway. However, little is known about the role of PTEN/Akt signaling in hypoxia-associated vascular remodeling. In this study, we found that hypoxia-induced the expression of Akt1 mRNA and phosphorylated protein by at least twofold in rat PASMCs. Phospho-PTEN significantly decreased in the nuclei of PASMCs after hypoxic stimulation. After forcing over-expression of PTEN by adenovirus-mediated PTEN (Ad-PTEN) transfection, the expression of phospho-Akt1 was significantly suppressed in PASMCs at all time-points measured. Additionally, we showed here that hypoxia increased proliferation of PASMCs by nearly twofold and over-expression of PTEN significantly inhibited hypoxia-induced PASMCs proliferation. These findings suggest that phospho-PTEN loss in the nuclei of PASMCs under hypoxic conditions may be the major cause of aberrant activation of Akt1 and may, therefore, play an important role in hypoxia-associated pulmonary arterial remodeling. Finally, the fact that transfection with Ad-PTEN inhibits the phosphorylation of Akt1 in PASMCs suggests a potential therapeutic effect on hypoxia-associated pulmonary arterial remodeling.

  4. Overexpression of LRIG1 regulates PTEN via MAPK/MEK signaling pathway in esophageal squamous cell carcinoma

    PubMed Central

    Jiang, Xiaofang; Li, Huiwu

    2016-01-01

    The present study aimed to evaluate the role of leucine-rich repeats and immunoglobulin-like domain protein 1 (LRIG1) in the regulation of phosphatase and tensin homolog (PTEN) expression in esophageal carcinogenesis. LRIG1 was overexpressed in esophageal squamous cell carcinoma (ESCC) cell lines, and the effect of LRIG1 overexpression on the mRNA and protein expression levels of PTEN was evaluated by reverse transcription-quantitative polymerase chain reaction and western blotting. Furthermore, the effects of LRIG1 overexpression on the cell cycle distribution and apoptosis of ESCC cells were examined by flow cytometry. Various cell signaling pathway inhibitors were used to assess the effects of LRIG1 on downstream signaling in ESCC cell lines. In addition, the association between LRIG1 and PTEN expression was examined in 48 samples from patients with ESCC. LRIG1 overexpression was demonstrated to downregulate PTEN expression in ESCC cell lines, and promote their proliferation and inhibit apoptosis. In addition, LRIG1-mediated suppression of PTEN expression was inhibited by the U0126 inhibitor, which suggests that LRIG1 may inhibit the activation of PTEN signaling molecules by triggering the mitogen-activated protein kinase (MAPK)/MAPK kinase 1 (MEK) signaling pathway. In conclusion, the present study demonstrated that overexpression of LRIG1 significantly and adversely affected the survival of ESCC cells, and that the MAPK/MEK signaling pathway may be responsible for the repression of PTEN expression and function. PMID:27698691

  5. Overexpression of LRIG1 regulates PTEN via MAPK/MEK signaling pathway in esophageal squamous cell carcinoma

    PubMed Central

    Jiang, Xiaofang; Li, Huiwu

    2016-01-01

    The present study aimed to evaluate the role of leucine-rich repeats and immunoglobulin-like domain protein 1 (LRIG1) in the regulation of phosphatase and tensin homolog (PTEN) expression in esophageal carcinogenesis. LRIG1 was overexpressed in esophageal squamous cell carcinoma (ESCC) cell lines, and the effect of LRIG1 overexpression on the mRNA and protein expression levels of PTEN was evaluated by reverse transcription-quantitative polymerase chain reaction and western blotting. Furthermore, the effects of LRIG1 overexpression on the cell cycle distribution and apoptosis of ESCC cells were examined by flow cytometry. Various cell signaling pathway inhibitors were used to assess the effects of LRIG1 on downstream signaling in ESCC cell lines. In addition, the association between LRIG1 and PTEN expression was examined in 48 samples from patients with ESCC. LRIG1 overexpression was demonstrated to downregulate PTEN expression in ESCC cell lines, and promote their proliferation and inhibit apoptosis. In addition, LRIG1-mediated suppression of PTEN expression was inhibited by the U0126 inhibitor, which suggests that LRIG1 may inhibit the activation of PTEN signaling molecules by triggering the mitogen-activated protein kinase (MAPK)/MAPK kinase 1 (MEK) signaling pathway. In conclusion, the present study demonstrated that overexpression of LRIG1 significantly and adversely affected the survival of ESCC cells, and that the MAPK/MEK signaling pathway may be responsible for the repression of PTEN expression and function.

  6. Restoring E-cadherin-mediated cell-cell adhesion increases PTEN protein level and stability in human breast carcinoma cells

    SciTech Connect

    Li Zengxia; Wang Liying; Zhang Wen; Fu Yi; Zhao Hongbo; Hu Yali; Prins, Bram Peter; Zha Xiliang

    2007-11-09

    The phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a well-characterized tumor suppressor that negatively regulates cell growth and survival. Despite the critical role of PTEN in cell signaling, the mechanisms of its regulation are still under investigation. We reported here that PTEN expression could be controlled by overexpression or knock-down of E-cadherin in several mammary carcinoma cell lines. Furthermore, we showed that the accumulation of PTEN protein in E-cadherin overexpressing cells was due to increased PTEN protein stability rather than the regulation of its transcription. The proteasome-dependent PTEN degradation pathway was impaired after restoring E-cadherin expression. Moreover, maintenance of E-cadherin mediated cell-cell adhesion was necessary for its regulating PTEN. Altogether, our results suggested that E-cadherin mediated cell-cell adhesion was essential for preventing the proteasome degradation of PTEN, which might explain how breast carcinoma cells which lost cell-cell contact proliferate rapidly and are prone to metastasis.

  7. Oridonin upregulates PTEN through activating p38 MAPK and inhibits proliferation in human colon cancer cells.

    PubMed

    Wu, Qiu-Xiang; Yuan, Shuang-Xue; Ren, Chun-Mei; Yu, Yu; Sun, Wen-Juan; He, Bai-Cheng; Wu, Ke

    2016-06-01

    Oridonin (ORI) has been reported as an antiproliferation and apoptosis-inducing natural product in various cancer cells. However, the exact molecular mechanism underlying these effects remains unclear. In the present study, we demonstrated the antiproliferation effect of ORI in HCT116 cells, and analyzed the possible molecular mechanism which mediates this effect. We found that ORI inhibits proliferation, induces cell cycle arrest and apoptosis in HCT116 cells, thus also tumor growth. Mechanically, we found that ORI has no substantial effect on mRNA expression of phosphatase and tensin homologue (PTEN), but increases the total protein level of PTEN and markedly reduces the phosphorylation of PTEN; Exogenous expression of PTEN potentiates the anticancer effect of ORI, while knockdown of PTEN attenuates it. ORI also increases the phosphorylation of p38 MAPK, and p38 MAPK-specific inhibitor reduces the antiproliferation effect ORI in HCT116 cells. Moreover, inhibition of p38 MAPK increases the phosphorylation of PTEN, and reverses ORI-induced decrease of PTEN phosphorylation. Our findings suggested that ORI may be a potential anticancer drug for colon cancer, this effect may be mediated by enhancing the function of PTEN through reducing its phosphorylation, which may be resulted from the ORI-induced activation of p38 MAPK.

  8. Interaction of E-cadherin and PTEN regulates morphogenesis and growth arrest in human mammary epithelial cells

    SciTech Connect

    Fournier, Marcia V.; Fata, Jimmie E.; Martin, Katherine J.; Yaswen, Paul; Bissell, Mina J.

    2009-06-03

    PTEN is a dual function phosphatase with tumor suppressor function compromised in a wide spectrum of cancers. Because tissue polarity and architecture are crucial modulators of normal and malignant behavior, we postulated that PTEN may play a role in maintenance of tissue integrity. We used two non-malignant human mammary epithelial cell lines (HMECs) that form polarized, growth-arrested structures (acini) when cultured in 3-dimensional laminin-rich extracellular matrix gels (3D lrECM). As acini begin to form, PTEN accumulates in both the cytoplasm, and at cell-cell contacts where it colocalizes with E-cadherin/{beta}-catenin complex. Reduction of PTEN levels by shRNA in lrECM prevents formation of organized breast acini and disrupts growth arrest. Importantly, disruption of acinar polarity and cell-cell contact by E-cadherin function-blocking antibodies reduces endogenous PTEN protein levels and inhibits its accumulation at cell-cell contacts. Conversely, in SKBR3 breast cancer cells lacking endogenous E-cadherin expression, exogenous introduction of E-cadherin gene causes induction of PTEN expression and its accumulation at sites of cell interactions. These studies provide evidence that E-cadherin regulates both the PTEN protein levels and its recruitment to cell-cell junctions in 3D lrECM indicating a dynamic reciprocity between architectural integrity and the levels and localization of PTEN. This interaction thus appears to be a critical integrator of proliferative and morphogenetic signaling in breast epithelial cells.

  9. PTEN ameliorates autoimmune arthritis through down-regulating STAT3 activation with reciprocal balance of Th17 and Tregs

    PubMed Central

    Lee, Seung Hoon; Park, Jin-Sil; Byun, Jae-Kyung; Jhun, JooYeon; Jung, KyungAh; Seo, Hyeon-Beom; Moon, Young-Mee; Kim, Ho-Youn; Park, Sung-Hwan; Cho, Mi-La

    2016-01-01

    PTEN is a tyrosine phosphatase with significant function in inhibiting STAT3 activation. Recently, inactivation of STAT3 has been demonstrated as a therapeutic candidate for autoimmune arthritis. The expression of PTEN controlled by p53 regulates autoimmune arthritis through modulating the balance between Th17 and Treg. We hypothesized that PTEN regulated by p53 might reduce CIA severity and inflammatory response via inhibiting STAT3 activation. Our results revealed that PTEN could ameliorate experimental autoimmune arthritis by reducing STAT3 activity and Th17 differentiation. Systemic infusion of PTEN overexpression downregulated CIA severity. In addition, PTEN overexpression decreased the activation of T cells and modulated reciprocal differentiation of Th17 and Treg cells. We observed that PTEN expression downregulated by p53 deficiency induced the activation of STAT3. Loss of p53 exacerbated autoimmune arthritis and dysregulated the population of Th17 and Treg. These data suggest that induction of STAT3-modulatory activity of PTEN may be a therapeutic target for rheumatoid arthritis therapy. PMID:27708408

  10. Vibrational force alters mRNA expression in osteoblasts

    NASA Technical Reports Server (NTRS)

    Tjandrawinata, R. R.; Vincent, V. L.; Hughes-Fulford, M.

    1997-01-01

    Serum-deprived mouse osteoblastic (MC3T3E1) cells were subjected to a vibrational force modeled by NASA to simulate a space shuttle launch (7.83 G rms). The mRNA levels for eight genes were investigated to determine the effect of vibrational force on mRNA expression. The mRNA levels of two growth-related protooncogenes, c-fos and c-myc, were up-regulated significantly within 30 min after vibration, whereas those of osteocalcin as well as transforming growth factor-beta1 were decreased significantly within 3 h after vibration. No changes were detected in the levels of beta-actin, histone H4, or cytoplasmic phospholipase A2 after vibration. No basal levels of cyclooxygenase-2 expression were detected. In addition, the extracellular concentrations of prostaglandin E2 (PGE2), a potent autocrine/paracrine growth factor in bone, were not significantly altered after vibration most likely due to the serum deprivation state of the osteoblasts. In comparison with the gravitational launch profile, vibrational-induced changes in gene expression were greater both in magnitude and number of genes activated. Taken together, these data suggest that the changes in mRNA expression are due to a direct mechanical effect of the vibrational force on the osteoblast cells and not to changes in the local PGE2 concentrations. The finding that launch forces induce gene expression is of utmost importance since many of the biological experiments do not dampen vibrational loads on experimental samples. This lack of dampening of vibrational forces may partially explain why 1-G onboard controls sometimes do not reflect 1-G ground controls. These data may also suggest that scientists use extra ground controls that are exposed to launch forces, have these forces dampened on launched samples, or use facilities such as Biorack that provide an onboard 1-G centrufuge in order to control for space shuttle launch forces.

  11. Vibrational force alters mRNA expression in osteoblasts.

    PubMed

    Tjandrawinata, R R; Vincent, V L; Hughes-Fulford, M

    1997-05-01

    Serum-deprived mouse osteoblastic (MC3T3E1) cells were subjected to a vibrational force modeled by NASA to simulate a space shuttle launch (7.83 G rms). The mRNA levels for eight genes were investigated to determine the effect of vibrational force on mRNA expression. The mRNA levels of two growth-related protooncogenes, c-fos and c-myc, were up-regulated significantly within 30 min after vibration, whereas those of osteocalcin as well as transforming growth factor-beta1 were decreased significantly within 3 h after vibration. No changes were detected in the levels of beta-actin, histone H4, or cytoplasmic phospholipase A2 after vibration. No basal levels of cyclooxygenase-2 expression were detected. In addition, the extracellular concentrations of prostaglandin E2 (PGE2), a potent autocrine/paracrine growth factor in bone, were not significantly altered after vibration most likely due to the serum deprivation state of the osteoblasts. In comparison with the gravitational launch profile, vibrational-induced changes in gene expression were greater both in magnitude and number of genes activated. Taken together, these data suggest that the changes in mRNA expression are due to a direct mechanical effect of the vibrational force on the osteoblast cells and not to changes in the local PGE2 concentrations. The finding that launch forces induce gene expression is of utmost importance since many of the biological experiments do not dampen vibrational loads on experimental samples. This lack of dampening of vibrational forces may partially explain why 1-G onboard controls sometimes do not reflect 1-G ground controls. These data may also suggest that scientists use extra ground controls that are exposed to launch forces, have these forces dampened on launched samples, or use facilities such as Biorack that provide an onboard 1-G centrufuge in order to control for space shuttle launch forces.

  12. The AKT inhibitor AZD5363 is selectively active in PI3KCA mutant gastric cancer, and sensitizes a patient-derived gastric cancer xenograft model with PTEN loss to Taxotere

    PubMed Central

    2013-01-01

    Introduction Activation of the PI3K/AKT pathway is a common phenomenon in cancer due to multiple mechanisms, including mutation of PI3KCA, loss or mutation of PTEN, or over-expression of receptor tyrosine kinases. We recently developed a novel AKT kinase inhibitor, AZD5363, and demonstrated that HGC27, a cell line harboring both PI3KCA mutation and PTEN loss, displayed the greatest sensitivity to this AKT inhibitor in vitro and in vivo. Case preparation To further elucidate the correlation between AZD5363 response and genetic alterations in gastric cancer (GC) and identify GC patients with both PI3KCA mutations and PTEN loss, we investigated the effects of pharmacological inhibition of AKT on a panel of 20 GC cell lines and genetic aberrations in tumor samples from a cohort of Chinese GC patients. We demonstrated that GC cells with PI3KCA mutations were selectively sensitive to AZD5363. Disease linkage studies showed that PI3KCA activating mutations or PTEN loss were found in 2.7% (4/150) and 23% (14/61) of Chinese GC patients respectively. To further dissect the role of PI3KCA mutation and PTEN loss in response to AKT inhibition, we tested the antitumor activity of AZD5363 in two patient-derived GC xenograft (PDGCX) models harboring either PI3KCA mutation or PTEN loss. Our data indicated that AZD5363 monotherapy treatment led to a moderate response in the PI3KCA mutant PDGCX model. Whilst monotherapy AZD5363 or Taxotere were ineffective in the PTEN negative PDGCX model, significant anti-tumor activity was observed when AZD5363 was combined with Taxotere. Conclusion Our results indicated that PI3KCA mutation is an important determinant of response to AKT inhibition in GC and combination with AZD5363 can overcome innate resistance to Taxotere in a PTEN loss PDGCX model. It is suggested that AKT inhibitor is an attractive option for treatment of a new segment of GC patients with aberrant PI3K/AKT signaling. PMID:24088382

  13. Network Clustering Revealed the Systemic Alterations of Mitochondrial Protein Expression

    PubMed Central

    Koo, Hyun-Jung; Park, Wook-Ha; Yang, Jae-Seong; Yu, Myeong-Hee; Kim, Sanguk; Pak, Youngmi Kim

    2011-01-01

    The mitochondrial protein repertoire varies depending on the cellular state. Protein component modifications caused by mitochondrial DNA (mtDNA) depletion are related to a wide range of human diseases; however, little is known about how nuclear-encoded mitochondrial proteins (mt proteome) changes under such dysfunctional states. In this study, we investigated the systemic alterations of mtDNA-depleted (ρ0) mitochondria by using network analysis of gene expression data. By modularizing the quantified proteomics data into protein functional networks, systemic properties of mitochondrial dysfunction were analyzed. We discovered that up-regulated and down-regulated proteins were organized into two predominant subnetworks that exhibited distinct biological processes. The down-regulated network modules are involved in typical mitochondrial functions, while up-regulated proteins are responsible for mtDNA repair and regulation of mt protein expression and transport. Furthermore, comparisons of proteome and transcriptome data revealed that ρ0 cells attempted to compensate for mtDNA depletion by modulating the coordinated expression/transport of mt proteins. Our results demonstrate that mt protein composition changed to remodel the functional organization of mitochondrial protein networks in response to dysfunctional cellular states. Human mt protein functional networks provide a framework for understanding how cells respond to mitochondrial dysfunctions. PMID:21738461

  14. PTEN inhibition to facilitate intrinsic regenerative outgrowth of adult peripheral axons.

    PubMed

    Christie, Kimberly J; Webber, Christine A; Martinez, Jose A; Singh, Bhagat; Zochodne, Douglas W

    2010-07-01

    In vivo regeneration of peripheral neurons is constrained and rarely complete, and unfortunately patients with major nerve trunk transections experience only limited recovery. Intracellular inhibition of neuronal growth signals may be among these constraints. In this work, we investigated the role of PTEN (phosphatase and tensin homolog deleted on chromosome 10) during regeneration of peripheral neurons in adult Sprague Dawley rats. PTEN inhibits phosphoinositide 3-kinase (PI3-K)/Akt signaling, a common and central outgrowth and survival pathway downstream of neuronal growth factors. While PI3-K and Akt outgrowth signals were expressed and activated within adult peripheral neurons during regeneration, PTEN was similarly expressed and poised to inhibit their support. PTEN was expressed in neuron perikaryal cytoplasm, nuclei, regenerating axons, and Schwann cells. Adult sensory neurons in vitro responded to both graded pharmacological inhibition of PTEN and its mRNA knockdown using siRNA. Both approaches were associated with robust rises in the plasticity of neurite outgrowth that were independent of the mTOR (mammalian target of rapamycin) pathway. Importantly, this accelerated outgrowth was in addition to the increased outgrowth generated in neurons that had undergone a preconditioning lesion. Moreover, following severe nerve transection injuries, local pharmacological inhibition of PTEN or siRNA knockdown of PTEN at the injury site accelerated axon outgrowth in vivo. The findings indicated a remarkable impact on peripheral neuron plasticity through PTEN inhibition, even within a complex regenerative milieu. Overall, these findings identify a novel route to propagate intrinsic regeneration pathways within axons to benefit nerve repair.

  15. Human cone pigment expressed in transgenic mice yields altered vision.

    PubMed

    Jacobs, G H; Fenwick, J C; Calderone, J B; Deeb, S S

    1999-04-15

    Genetically driven alterations in the complement of retinal photopigments are fundamental steps in the evolution of vision. We sought to determine how a newly added photopigment might impact vision by studying a transgenic mouse that expresses a human cone photopigment. Electroretinogram (ERG) measurements indicate that the added pigment works well, significantly changing spectral sensitivity without deleteriously affecting the operation of the native cone pigments. Visual capacities of the transgenic mice were established in behavioral tests. The new pigment was found to provide a significant expansion of the spectral range over which mice can perceive light, thus underlining the immediate utility of acquiring a new photopigment. The transgenic mouse also has the receptor basis for a novel color vision capacity, but tests show that potential was not realized. This failure likely reflects limitations in the organizational arrangement of the mouse retina.

  16. Ezrin-radixin-moesin-binding phosphoprotein-50 regulates EGF-induced AKT activation through interaction with EGFR and PTEN.

    PubMed

    Zheng, Junfang; Dai, Yuanping; Yang, Zhiyu; Yang, Longyan; Peng, Zhiqiang; Meng, Ran; Xiong, Ying; He, Junqi

    2016-01-01

    Dysregulated epidermal growth factor receptor (EGFR) signaling, especially EGFR/AKT signaling, plays important roles in tumorigenesis and progression, the study on intracellular regulation of this signaling pathway has great clinical significance. Phosphatase and tensin homolog deleted on chromosome ten (PTEN) is an important antagonist of AKT activity. Its regulation of AKT activity can be enhanced by ezrin-radixin-moesin-binding phosphoprotein-50 (EBP50)-mediated PTEN/EBP50/platelet-derived growth factor receptor (PDGFR) complex. EBP50 was reported to bind to EGFR, and that it may also mediate the formation of PTEN/EGFR complex to regulate EGFR/AKT signaling. In this study, experiments were performed to verify the hypothesis. Results showed that PTEN co-immunoprecipitated with EGFR, demonstrating PTEN/EGFR complex can form in tissue. Further studies showed that EBP50 knockdown decreased the amount of PTEN/EGFR complex by GST pull-down assay, and EBP50 overexpression increased the amount of PTEN/EGFR complex in a dose-dependent manner. While PTEN mutant (V403A), which can not bind with EBP50, only slightly mediated the formation of PTEN/EGFR complex, confirming that EBP50 specifically mediated the formation of the PTEN/EGFR complex. Both PTEN (V403A) and EGFR (L1043/1063F) mutants can not bind with EBP50. The expression of PTEN (V403A) or EGFR (L1043/1063F) mutant in cells resulted in higher AKT activation level than their respective wild-types by EGF stimulation, indicating that EBP50-mediated PTEN/EGFR complex can effectively inhibit EGF-induced AKT activation. EGF stimulation of siEBP50 cells induced higher AKT activation level compared with control cells, further confirming EBP50-mediated PTEN/EGFR complex can more effectively inhibit EGF-induced AKT activation. These results demonstrated the PTEN/EGFR complex formed under the mediation of EBP50, revealing a novel mechanism for negative regulation of EGF-induced AKT pathway, which may be an important molecular

  17. PTEN functions by recruitment to cytoplasmic vesicles.

    PubMed

    Naguib, Adam; Bencze, Gyula; Cho, Hyejin; Zheng, Wu; Tocilj, Ante; Elkayam, Elad; Faehnle, Christopher R; Jaber, Nadia; Pratt, Christopher P; Chen, Muhan; Zong, Wei-Xing; Marks, Michael S; Joshua-Tor, Leemor; Pappin, Darryl J; Trotman, Lloyd C

    2015-04-16

    PTEN is proposed to function at the plasma membrane, where receptor tyrosine kinases are activated. However, the majority of PTEN is located throughout the cytoplasm. Here, we show that cytoplasmic PTEN is distributed along microtubules, tethered to vesicles via phosphatidylinositol 3-phosphate (PI(3)P), the signature lipid of endosomes. We demonstrate that the non-catalytic C2 domain of PTEN specifically binds PI(3)P through the CBR3 loop. Mutations render this loop incapable of PI(3)P binding and abrogate PTEN-mediated inhibition of PI 3-kinase/AKT signaling. This loss of function is rescued by fusion of the loop mutant PTEN to FYVE, the canonical PI(3)P binding domain, demonstrating the functional importance of targeting PTEN to endosomal membranes. Beyond revealing an upstream activation mechanism of PTEN, our data introduce the concept of PI 3-kinase signal activation on the vast plasma membrane that is contrasted by PTEN-mediated signal termination on the small, discrete surfaces of internalized vesicles. PMID:25866245

  18. Germline disruption of Pten localization causes enhanced sex-dependent social motivation and increased glial production

    PubMed Central

    Tilot, Amanda K.; Gaugler, Mary K.; Yu, Qi; Romigh, Todd; Yu, Wanfeng; Miller, Robert H.; Frazier, Thomas W.; Eng, Charis

    2014-01-01

    PTEN Hamartoma Tumor Syndrome (PHTS) is an autosomal-dominant genetic condition underlying a subset of autism spectrum disorder (ASD) with macrocephaly. Caused by germline mutations in PTEN, PHTS also causes increased risks of multiple cancers via dysregulation of the PI3K and MAPK signaling pathways. Conditional knockout models have shown that neural Pten regulates social behavior, proliferation and cell size. Although much is known about how the intracellular localization of PTEN regulates signaling in cancer cell lines, we know little of how PTEN localization influences normal brain physiology and behavior. To address this, we generated a germline knock-in mouse model of cytoplasm-predominant Pten and characterized its behavioral and cellular phenotypes. The homozygous Ptenm3m4 mice have decreased total Pten levels including a specific drop in nuclear Pten and exhibit region-specific increases in brain weight. The Ptenm3m4 model displays sex-specific increases in social motivation, poor balance and normal recognition memory—a profile reminiscent of some individuals with high functioning ASD. The cytoplasm-predominant protein caused cellular hypertrophy limited to the soma and led to increased NG2 cell proliferation and accumulation of glia. The animals also exhibit significant astrogliosis and microglial activation, indicating a neuroinflammatory phenotype. At the signaling level, Ptenm3m4 mice show brain region-specific differences in Akt activation. These results demonstrate that differing alterations to the same autism-linked gene can cause distinct behavioral profiles. The Ptenm3m4 model is the first murine model of inappropriately elevated social motivation in the context of normal cognition and may expand the range of autism-related behaviors replicated in animal models. PMID:24470394

  19. Myeloid PTEN deficiency protects livers from ischemia reperfusion injury by facilitating M2 macrophage differentiation.

    PubMed

    Yue, Shi; Rao, Jianhua; Zhu, Jianjun; Busuttil, Ronald W; Kupiec-Weglinski, Jerzy W; Lu, Ling; Wang, Xuehao; Zhai, Yuan

    2014-06-01

    Although the role of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in regulating cell proliferation is well established, its function in immune responses remains to be fully appreciated. In the current study, we analyzed myeloid-specific PTEN function in regulating tissue inflammatory immune response in a murine liver partial warm ischemia model. Myeloid-specific PTEN knockout (KO) resulted in liver protection from ischemia reperfusion injury (IRI) by deviating the local innate immune response against ischemia reperfusion toward the regulatory type: expression of proinflammatory genes was selectively decreased and anti-inflammatory IL-10 was simultaneously increased in ischemia reperfusion livers of PTEN KO mice compared with those of wild-type (WT) mice. PI3K inhibitor and IL-10-neutralizing Abs, but not exogenous LPS, recreated liver IRI in these KO mice. At the cellular level, Kupffer cells and peritoneal macrophages isolated from KO mice expressed higher levels of M2 markers and produced lower TNF-α and higher IL-10 in response to TLR ligands than did their WT counterparts. They had enhanced Stat3- and Stat6-signaling pathway activation, but diminished Stat1-signaling pathway activation, in response to TLR4 stimulation. Inactivation of Kupffer cells by gadolinium chloride enhanced proinflammatory immune activation and increased IRI in livers of myeloid PTEN KO mice. Thus, myeloid PTEN deficiency protects livers from IRI by facilitating M2 macrophage differentiation. PMID:24771857

  20. Cross talk between miR-214 and PTEN attenuates glomerular hypertrophy under diabetic conditions

    PubMed Central

    Wang, Xiaoxia; Shen, E.; Wang, Yanzhe; Li, Junhui; Cheng, Dongsheng; Chen, Yuqiang; Gui, Dingkun; Wang, Niansong

    2016-01-01

    Glomerular mesangial cells (MCs) hypertrophy is one of the earliest pathological abnormalities in diabetic nephropathy (DN), which correlates with eventual glomerulosclerosis. This study aimed to investigate the therapeutic role of miRNA in diabetic glomerular MCs hypertrophy and synthesis of extracellular matrix (ECM). Microarray analysis revealed a significant up-regulation of miR-214 in the renal cortex of diabetic db/db mice, which was confirmed by real-time PCR of isolated glomeruli and primary cultured human MCs. In vitro studies showed that inhibition of miR-214 significantly reduced expression of α-SMA, SM22 and collagen IV, and partially restored phosphatase and tensin homolog (PTEN) protein level in high glucose-stimulated human MCs. Furthermore, we identified PTEN as the target of miR-214 by a luciferase assay in HEK293 cells. Moreover, overexpression of PTEN ameliorated miR-214-mediated diabetic MC hypertrophy while knockdown of PTEN mimicked the MC hypertrophy. In vivo study further confirmed that inhibition of miR-214 significantly decreased the expression of SM22, α-SMA and collagen IV, partially restored PTEN level, and attenuated albuminuria and mesangial expansion in db/db mice. In conclusion, cross talk between miR-214 and PTEN attenuated glomerular hypertrophy under diabetic conditions in vivo and in vitro. Therefore, miR-214 may represent a novel therapeutic target for DN. PMID:27549568

  1. Cross talk between miR-214 and PTEN attenuates glomerular hypertrophy under diabetic conditions.

    PubMed

    Wang, Xiaoxia; Shen, E; Wang, Yanzhe; Li, Junhui; Cheng, Dongsheng; Chen, Yuqiang; Gui, Dingkun; Wang, Niansong

    2016-01-01

    Glomerular mesangial cells (MCs) hypertrophy is one of the earliest pathological abnormalities in diabetic nephropathy (DN), which correlates with eventual glomerulosclerosis. This study aimed to investigate the therapeutic role of miRNA in diabetic glomerular MCs hypertrophy and synthesis of extracellular matrix (ECM). Microarray analysis revealed a significant up-regulation of miR-214 in the renal cortex of diabetic db/db mice, which was confirmed by real-time PCR of isolated glomeruli and primary cultured human MCs. In vitro studies showed that inhibition of miR-214 significantly reduced expression of α-SMA, SM22 and collagen IV, and partially restored phosphatase and tensin homolog (PTEN) protein level in high glucose-stimulated human MCs. Furthermore, we identified PTEN as the target of miR-214 by a luciferase assay in HEK293 cells. Moreover, overexpression of PTEN ameliorated miR-214-mediated diabetic MC hypertrophy while knockdown of PTEN mimicked the MC hypertrophy. In vivo study further confirmed that inhibition of miR-214 significantly decreased the expression of SM22, α-SMA and collagen IV, partially restored PTEN level, and attenuated albuminuria and mesangial expansion in db/db mice. In conclusion, cross talk between miR-214 and PTEN attenuated glomerular hypertrophy under diabetic conditions in vivo and in vitro. Therefore, miR-214 may represent a novel therapeutic target for DN. PMID:27549568

  2. MMAC/PTEN tumor suppressor gene regulates vascular endothelial growth factor-mediated angiogenesis in prostate cancer.

    PubMed

    Koul, Dimpy; Shen, Ruijun; Garyali, Anil; Ke, L D; Liu, Ta-Jen; Yung, W K Alfred

    2002-09-01

    Prostate cancer presents with a broad spectrum of biologic behavior, ranging from being an indolent, incidental finding to an aggressively invasive and metastatic disease. An improved understanding of the events involved in prostate cancer progression is critically important to its diagnosis and staging, as well as to the development of new therapies. Tumor progression, particularly in aggressive and malignant tumors, is associated with the induction of an angiogenic, gene-driven switch. In prostate cancer, one of the most powerful stimulators of angiogenesis is the vascular endothelial growth factor (VEGF). VEGF transcription can be induced by hypoxia through activation of the PI3 kinase pathway and hypoxia-inducible factor alpha. MMAC/PTEN (henceforth referred to as PTEN) is a recently identified tumor suppressor gene residing on chromosome 10q23, which is frequently inactivated in a wide range of human tumors, including advanced prostate cancer. The goal of this study was to determine whether PTEN inhibits angiogenesis by modulating VEGF activity. Our results showed that reintroduction of the PTEN gene into human prostate PC-3 and LNCaP cells decreased VEGF secretion, which was accompanied by various biologic activities, including inhibited endothelial cell growth and migration. PTEN expression also down-regulated VEGF mRNA levels, as detected by RT-PCR analysis. Concomitant with lessened VEGF expression was the reduction of VEGF promoter activity in PTEN-expressing cells. Our findings suggest that PTEN modulates angiogenesis by regulating VEGF expression.

  3. Altered Gene Expression in Mice Selected for High Maternal Aggression

    PubMed Central

    Gammie, Stephen C.; Auger, Anthony P.; Jessen, Heather M.; Vanzo, Rena J.; Awad, Tarif A.; Stevenson, Sharon A.

    2007-01-01

    We previously applied selective breeding on outbred mice to increase maternal aggression (maternal defense). In this study, we compared gene expression within a continuous region of the CNS involved in maternal aggression (hypothalamus and preoptic regions) between lactating selected (S) and non-selected control (C) mice (n = 6 per group). Using microarrays representing over 40,000 genes or expressed sequence tags, two statistical algorithms were used to identify significant differences in gene expression: robust multi array and the probe logarithmic intensity error method. ∼ 200 genes were identified as significant using an intersection from both techniques. A subset of genes were examined for confirmation by real-time PCR. Significant decreases were found in S mice for neurotensin and neuropeptide Y receptor Y2 (both confirmed by PCR). Significant increases were found in S mice for neuronal nitric oxide synthase (confirmed by PCR), the K+ channel subunit, Kcna1 (confirmed by PCR), corticotrophin releasing factor binding protein (just above significance using PCR; p = 0.051), and GABA A receptor subunit 1A (not confirmed by PCR, but similar direction). S mice also exhibited significantly higher levels of the neurotransmitter receptor, adenosine A1 receptor, and the transcription factors, c-Fos, and Egr-1. Interestingly, for 24 genes related to metabolism, all were significantly elevated in S mice, suggesting altered metabolism in these mice. Together, this study provides a list of candidate genes (some previously implicated in maternal aggression and some novel) that may play an important role in the production of this behavior. PMID:16939635

  4. Catalysis by the tumor-suppressor enzymes PTEN and PTEN-L.

    PubMed

    Johnston, Sean B; Raines, Ronald T

    2015-01-01

    Phosphatase and tensin homologue deleted from chromosome ten (PTEN) is a lipid phosphatase tumor suppressor that is lost or inactivated in most human tumors. The enzyme catalyzes the hydrolysis of phosphatidylinositol-(3,4,5)-trisphosphate (PIP3) to form phosphatidylinositol-(4,5)-bisphosphate (PIP2) and inorganic phosphate. Here, we report on the first continuous assay for the catalytic activity of PTEN. Using this assay, we demonstrate that human PTEN is activated by the reaction product PIP2, as well as in solutions of low salt concentration. This activation is abrogated in the K13A variant, which has a disruption in a putative binding site for PIP2. We also demonstrate that PTEN-L, which derives from alternative translation of the PTEN mRNA, is activated constitutively. These findings have implications for catalysis by PTEN in physiological environments and could expedite the development of PTEN-based chemotherapeutic agents.

  5. Glandular epithelial AR inactivation enhances PTEN deletion-induced uterine pathology.

    PubMed

    Choi, Jaesung Peter; Zheng, Yu; Handelsman, David J; Simanainen, Ulla

    2016-05-01

    Phosphatase and tensin homolog (PTEN) deletion induces uterine pathology, whereas androgen actions via androgen receptor (AR) support uterine growth and therefore may modify uterine cancer risk. We hypothesized that the androgen actions mediated via uterine glandular epithelial AR could modify PTEN deletion-induced uterine pathology. To test our hypothesis, we developed uterine glandular epithelium-specific PTEN and/or AR knockout mouse models comparing the uterine pathology among wild-type (WT), glandular epithelium-specific AR inactivation (ugeARKO), PTEN deletion (ugePTENKO), and the combined PTEN and AR knockout (ugePTENARKO) female mice. The double knockout restricted to glandular epithelium showed that AR inactivation enhanced PTEN deletion-induced uterine pathology with development of intraepithelial neoplasia by 20 weeks of age. In ugePTENARKO, 6/10 (60%) developed intraepithelial neoplasia, whereas 3/10 (30%) developed only glandular hyperplasia in ugePTENKO uterus. No uterine pathology was observed in WT (n=8) and ugeARKO (n=7) uteri. Uterine weight was significantly (P=0.002) increased in ugePTENARKO (374±97 mg (mean±s.e.)) compared with WT (97±6 mg), ugeARKO (94±12 mg), and ugePTENKO (205±33 mg). Estrogen receptor alpha (ERα) and P-AKT expression was modified by uterine pathology but did not differ between ugePTENKO and ugePTENARKO, suggesting that its expressions are not directly affected by androgens. However, progesterone receptor (PR) expression was reduced in ugePTENARKO compared to ugePTENKO uterus, suggesting that PR expression could be regulated by glandular epithelial AR inactivation. In conclusion, glandular epithelial AR inactivation (with persistent stromal AR action) enhanced PTEN deletion-induced uterine pathology possibly by downregulating PR expression in the uterus.

  6. PTEN regulates angiogenesis through PI3K/Akt/VEGF signaling pathway in human pancreatic cancer cells.

    PubMed

    Ma, Jiachi; Sawai, Hirozumi; Ochi, Nobuo; Matsuo, Yoichi; Xu, Donghui; Yasuda, Akira; Takahashi, Hiroki; Wakasugi, Takehiro; Takeyama, Hiromitsu

    2009-11-01

    Phosphoinositide 3-kinase (PI3K) pathway exerts its effects through Akt, its downstream target molecule, and thereby regulates various cell functions including cell proliferation, cell transformation, apoptosis, tumor growth, and angiogenesis. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) has been implicated in regulating cell survival signaling through the PI3K/Akt pathway. However, the mechanism by PI3K/PTEN signaling regulates angiogenesis and tumor growth in vivo remains to be elucidated. Vascular endothelial growth factor (VEGF) plays a pivotal role in tumor angiogenesis. The effect of PTEN on VEGF-mediated signal in pancreatic cancer is unknown. This study aimed to determine the effect of PTEN on both the expression of VEGF and angiogenesis. Toward that end, we used the siRNA knockdown method to specifically define the role of PTEN in the expression of VEGF and angiogenesis. We found that siRNA-mediated inhibition of PTEN gene expression in pancreatic cancer cells increase their VEGF secretion, up-modulated the proliferation, and migration of co-cultured vascular endothelial cell and enhanced tubule formation by HUVEC. In addition, PTEN modulated VEGF-mediated signaling and affected tumor angiogenesis through PI3K/Akt/VEGF/eNOS pathway.

  7. In vivo identification of tumor- suppressive PTEN ceRNAs in an oncogenic BRAF-induced mouse model of melanoma.

    PubMed

    Karreth, Florian A; Tay, Yvonne; Perna, Daniele; Ala, Ugo; Tan, Shen Mynn; Rust, Alistair G; DeNicola, Gina; Webster, Kaitlyn A; Weiss, Dror; Perez-Mancera, Pedro A; Krauthammer, Michael; Halaban, Ruth; Provero, Paolo; Adams, David J; Tuveson, David A; Pandolfi, Pier Paolo

    2011-10-14

    We recently proposed that competitive endogenous RNAs (ceRNAs) sequester microRNAs to regulate mRNA transcripts containing common microRNA recognition elements (MREs). However, the functional role of ceRNAs in cancer remains unknown. Loss of PTEN, a tumor suppressor regulated by ceRNA activity, frequently occurs in melanoma. Here, we report the discovery of significant enrichment of putative PTEN ceRNAs among genes whose loss accelerates tumorigenesis following Sleeping Beauty insertional mutagenesis in a mouse model of melanoma. We validated several putative PTEN ceRNAs and further characterized one, the ZEB2 transcript. We show that ZEB2 modulates PTEN protein levels in a microRNA-dependent, protein coding-independent manner. Attenuation of ZEB2 expression activates the PI3K/AKT pathway, enhances cell transformation, and commonly occurs in human melanomas and other cancers expressing low PTEN levels. Our study genetically identifies multiple putative microRNA decoys for PTEN, validates ZEB2 mRNA as a bona fide PTEN ceRNA, and demonstrates that abrogated ZEB2 expression cooperates with BRAF(V600E) to promote melanomagenesis. PMID:22000016

  8. Microenvironment-induced PTEN loss by exosomal microRNA primes brain metastasis outgrowth

    PubMed Central

    Yao, Jun; Lowery, Frank J.; Zhang, Qingling; Huang, Wen-Chien; Li, Ping; Li, Min; Wang, Xiao; Zhang, Chenyu; Wang, Hai; Ellis, Kenneth; Cheerathodi, Mujeeburahiman; McCarty, Joseph H.; Palmieri, Diane; Saunus, Jodi; Lakhani, Sunil; Huang, Suyun; Sahin, Aysegul A.; Aldape, Kenneth D.; Steeg, Patricia S.; Yu, Dihua

    2016-01-01

    Summary Development of life-threatening cancer metastases at distant organs requires disseminated tumor cells’ adaptation to and co-evolution with the drastically different microenvironments of metastatic sites1. Cancer cells of common origin manifest distinct gene expression patterns after metastasizing to different organs2. Clearly, the dynamic interplay between metastatic tumor cells and extrinsic signals at individual metastatic organ sites critically impacts the subsequent metastatic outgrowth3,4. Yet, it is unclear when and how disseminated tumor cells acquire the essential traits from the microenvironment of metastatic organs that prime their subsequent outgrowth. Here we show that primary tumor cells with normal expression of PTEN, an important tumor suppressor, lose PTEN expression after dissemination to the brain, but not to other organs. PTEN level in PTEN-loss brain metastatic tumor cells is restored after leaving brain microenvironment. This brain microenvironment-dependent, reversible PTEN mRNA and protein down-regulation is epigenetically regulated by microRNAs (miRNAs) from astrocytes. Mechanistically, astrocyte-derived exosomes mediate an intercellular transfer of PTEN-targeting miRNAs to metastatic tumor cells, while astrocyte-specific depletion of PTEN-targeting miRNAs or blockade of astrocyte exosome secretion rescues the PTEN loss and suppresses brain metastasis in vivo. Furthermore, this adaptive PTEN loss in brain metastatic tumor cells leads to an increased secretion of cytokine chemokine (C-C motif) ligand 2 (CCL2), which recruits Iba1+ myeloid cells that reciprocally enhance outgrowth of brain metastatic tumor cells via enhanced proliferation and reduced apoptosis. Our findings demonstrate a remarkable plasticity of PTEN expression in metastatic tumor cells in response to different organ microenvironments, underpinning an essential role of co-evolution between the metastatic cells and their microenvironment during the adaptive metastatic

  9. Brain patterning perturbations following PTEN loss

    PubMed Central

    Veleva-Rotse, Biliana O.; Barnes, Anthony P.

    2014-01-01

    This review will consider the impact of compromised PTEN signaling in brain patterning. We approach understanding the contribution of PTEN to nervous system development by surveying the findings from the numerous genetic loss-of-function models that have been generated as well as other forms of PTEN inactivation. By exploring the developmental programs influenced by this central transduction molecule, we can begin to understand the molecular mechanisms that shape the developing brain. A wealth of data indicates that PTEN plays critical roles in a variety of stages during brain development. Many of them are considered here including: stem cell proliferation, fate determination, polarity, migration, process outgrowth, myelination and somatic hypertrophy. In many of these contexts, it is clear that PTEN phosphatase activity contributes to the observed effects of genetic deletion or depletion, however recent studies have also ascribed non-catalytic functions to PTEN in regulating cell function. We also explore the potential impact this alternative pool of PTEN may have on the developing brain. Together, these elements begin to form a clearer picture of how PTEN contributes to the emergence of brain structure and binds form and function in the nervous system. PMID:24860420

  10. Inhibition of hypothalamic MCT1 expression increases food intake and alters orexigenic and anorexigenic neuropeptide expression

    PubMed Central

    Elizondo-Vega, Roberto; Cortés-Campos, Christian; Barahona, María José; Carril, Claudio; Ordenes, Patricio; Salgado, Magdiel; Oyarce, Karina; García-Robles, María de los Angeles

    2016-01-01

    Hypothalamic glucosensing, which involves the detection of glucose concentration changes by brain cells and subsequent release of orexigenic or anorexigenic neuropeptides, is a crucial process that regulates feeding behavior. Arcuate nucleus (AN) neurons are classically thought to be responsible for hypothalamic glucosensing through a direct sensing mechanism; however, recent data has shown a metabolic interaction between tanycytes and AN neurons through lactate that may also be contributing to this process. Monocarboxylate transporter 1 (MCT1) is the main isoform expressed by tanycytes, which could facilitate lactate release to hypothalamic AN neurons. We hypothesize that MCT1 inhibition could alter the metabolic coupling between tanycytes and AN neurons, altering feeding behavior. To test this, we inhibited MCT1 expression using adenovirus-mediated transfection of a shRNA into the third ventricle, transducing ependymal wall cells and tanycytes. Neuropeptide expression and feeding behavior were measured in MCT1-inhibited animals after intracerebroventricular glucose administration following a fasting period. Results showed a loss in glucose regulation of orexigenic neuropeptides and an abnormal expression of anorexigenic neuropeptides in response to fasting. This was accompanied by an increase in food intake and in body weight gain. Taken together, these results indicate that MCT1 expression in tanycytes plays a role in feeding behavior regulation. PMID:27677351

  11. PTEN Phosphatase-Independent Maintenance of Glandular Morphology in a Predictive Colorectal Cancer Model System1

    PubMed Central

    Jagan, Ishaan C; Deevi, Ravi K; Fatehullah, Aliya; Topley, Rebecca; Eves, Joshua; Stevenson, Michael; Loughrey, Maurice; Arthur, Kenneth; Campbell, Frederick Charles

    2013-01-01

    Organotypic models may provide mechanistic insight into colorectal cancer (CRC) morphology. Three-dimensional (3D) colorectal gland formation is regulated by phosphatase and tensin homologue deleted on chromosome 10 (PTEN) coupling of cell division cycle 42 (cdc42) to atypical protein kinase C (aPKC). This study investigated PTEN phosphatase-dependent and phosphatase-independent morphogenic functions in 3D models and assessed translational relevance in human studies. Isogenic PTEN-expressing or PTEN-deficient 3D colorectal cultures were used. In translational studies, apical aPKC activity readout was assessed against apical membrane (AM) orientation and gland morphology in 3D models and human CRC. We found that catalytically active or inactive PTEN constructs containing an intact C2 domain enhanced cdc42 activity, whereas mutants of the C2 domain calcium binding region 3 membrane-binding loop (M-CBR3) were ineffective. The isolated PTEN C2 domain (C2) accumulated in membrane fractions, but C2 M-CBR3 remained in cytosol. Transfection of C2 but not C2 M-CBR3 rescued defective AM orientation and 3D morphogenesis of PTEN-deficient Caco-2 cultures. The signal intensity of apical phospho-aPKC correlated with that of Na+/H+ exchanger regulatory factor-1 (NHERF-1) in the 3D model. Apical NHERF-1 intensity thus provided readout of apical aPKC activity and associated with glandular morphology in the model system and human colon. Low apical NHERF-1 intensity in CRC associated with disruption of glandular architecture, high cancer grade, and metastatic dissemination. We conclude that the membrane-binding function of the catalytically inert PTEN C2 domain influences cdc42/aPKC-dependent AM dynamics and gland formation in a highly relevant 3D CRC morphogenesis model system. PMID:24348097

  12. Expression of Phosphatase and Tensin Homologue, phospho-Akt, and p53 in Acral Benign and Malignant Melanocytic Neoplasms (Benign Nevi, Dysplastic Nevi, and Acral Melanomas)

    PubMed Central

    Lyu, So Min; Wu, Ju Yeon; Byun, Ji Yeon; Choi, Hae Young; Park, Sang Hee

    2016-01-01

    Background The role of the phosphatidylinositol-3 kinase signaling pathway in the development of acral melanoma has recently gained evidence. Phosphatase and tensin homologue (PTEN), one of the key molecules in the pathway, acts as a tumor suppressor through either an Akt-dependent or Akt-independent pathway. Akt accelerates degradation of p53. Objective We assessed the expression of PTEN, phospho-Akt (p-Akt), and p53 by immunohistochemistry in benign acral nevi, acral dysplastic nevi, and acral melanomas in the radial growth phase and with a vertical growth component. Methods Ten specimens in each group were included. Paraffin-embedded specimens were immunostained with antibodies for PTEN, p-Akt, and p53. We scored both the staining intensity and the proportion of positive cells. The final score was calculated by multiplying the intensity score by the proportion score. Results All specimens of benign acral nevi except one showed some degree of PTEN-negative cells. The numbers of p-Akt and p53-positive cells were higher in acral dysplastic nevi and melanoma than in benign nevi. P-Akt scores were 1.7, 1.8, 2.6, and 4.4, and p53 scores were 2.0, 2.1, 3.8, and 4.1 in each group. PTEN and p-Akt scores in advanced acral melanoma were higher than in the other neoplasms. Conclusion The expression of PTEN was decreased and the expression of p-Akt was increased in acral melanoma, especially in advanced cases. The PTEN-induced pathway appears to affect the late stage of melanomagenesis. Altered expression of p-Akt is thought to be due to secondary changes following the loss of PTEN. PMID:27746632

  13. mTOR Signaling Feedback Modulates Mammary Epithelial Differentiation and Restrains Invasion Downstream of PTEN Loss

    PubMed Central

    Ghosh, Susmita; Varela, Lidenys; Sood, Akshay; Park, Ben Ho; Lotan, Tamara L.

    2013-01-01

    Oncogenic signaling pathways are tightly regulated by negative feedback circuits and relief of these circuits represents a common mechanism of tumor drug resistance. Although the significance of these feedback pathways for signal transduction is evident, their relevance for cellular differentiation and morphogenesis in a genetically-defined context is unclear. In this study, we used isogenic benign mammary organotypic cultures to interrogate the role of mTOR-mediated negative feedback in the specific setting of PTEN inactivation. We found that mTOR signaling promoted basal-like differentiation and repressed nuclear hormone receptor expression after short-term PTEN loss in murine cell cultures analyzed ex vivo. Unexpectedly, we found that PTEN inactivation inhibited growth factor-induced epithelial invasion, and that downstream mTOR-mediated signaling feedback was both necessary and sufficient for this effect. Mechanistically, using isogenic MCF10A cells with and without somaticPTEN deletion, we showed that mTOR inhibition promoted EGF-mediated epithelial invasion by de-repressing upstream EGFR, SRC and PI3K signaling. In addition to offering new signal transduction insights, these results bring to light a number of important and potentially clinically relevant cellular consequences of mTOR inhibition in the specific context of PTEN loss, including modulation of hormone and growth factor responsiveness and promotion of epithelial invasion. Our findings prompt future investigations of the possibility that mTOR inhibitor therapy may not only be ineffective but even deleterious in tumors with PTEN loss. PMID:23774212

  14. Microarray gene expression profiling of osteoarthritic bone suggests altered bone remodelling, WNT and transforming growth factor-β/bone morphogenic protein signalling

    PubMed Central

    Hopwood, Blair; Tsykin, Anna; Findlay, David M; Fazzalari, Nicola L

    2007-01-01

    Osteoarthritis (OA) is characterized by alterations to subchondral bone as well as articular cartilage. Changes to bone in OA have also been identified at sites distal to the affected joint, which include increased bone volume fraction and reduced bone mineralization. Altered bone remodelling has been proposed to underlie these bone changes in OA. To investigate the molecular basis for these changes, we performed microarray gene expression profiling of bone obtained at autopsy from individuals with no evidence of joint disease (control) and from individuals undergoing joint replacement surgery for either degenerative hip OA, or fractured neck of femur (osteoporosis [OP]). The OP sample set was included because an inverse association, with respect to bone density, has been observed between OA and the low bone density disease OP. Compugen human 19K-oligo microarray slides were used to compare the gene expression profiles of OA, control and OP bone samples. Four sets of samples were analyzed, comprising 10 OA-control female, 10 OA-control male, 10 OA-OP female and 9 OP-control female sample pairs. Print tip Lowess normalization and Bayesian statistical analyses were carried out using linear models for microarray analysis, which identified 150 differentially expressed genes in OA bone with t scores above 4. Twenty-five of these genes were then confirmed to be differentially expressed (P < 0.01) by real-time PCR analysis. A substantial number of the top-ranking differentially expressed genes identified in OA bone are known to play roles in osteoblasts, osteocytes and osteoclasts. Many of these genes are targets of either the WNT (wingless MMTV integration) signalling pathway (TWIST1, IBSP, S100A4, MMP25, RUNX2 and CD14) or the transforming growth factor (TGF)-β/bone morphogenic protein (BMP) signalling pathway (ADAMTS4, ADM, MEPE, GADD45B, COL4A1 and FST). Other differentially expressed genes included WNT (WNT5B, NHERF1, CTNNB1 and PTEN) and TGF-β/BMP (TGFB1, SMAD3

  15. Cooperative interactions of PTEN deficiency and RAS activation in melanoma metastasis.

    PubMed

    Kim, Minjung

    2010-11-01

    Melanoma displays frequent activation of RAS/RAF/MAPK and PI3K/AKT signaling pathways as well as inactivation of CDKN2A (INK4a/ARF) and PTEN tumor suppressors via genetic and epigenetic alterations. Pathogenetic roles of these melanoma-prone mutations and their genetic interactions have been established in genetically engineered mouse models. Here, we catalog frequent genetic alterations observed in human melanomas and describe mouse models of melanoma initiation and progression, including our recent study that investigated the genetic interactions of RAS activation and PTEN loss in a CDKN2A (INK4a/ARF) null melanoma prone genetic background. We showed that loss of PTEN cooperates with HRAS activation, leading to increased development of melanoma and emergence of metastasis. Moreover, we observed that RNA i-mediated PTEN inactivation in RAS-driven melanomas enhanced migration and invasion with concomitant downregulation of E-cadherin, the major regulator of epithelial and mesenchymal transition, and enhanced AKT2 phosphorylation, which has been previously linked to invasion and metastasis of several cancer types, including breast and ovary. These data show that activated RAS cooperates with PTEN loss in melanoma genesis and progression.

  16. Loss of TGF-β signaling and PTEN promotes head and neck squamous cell carcinoma through cellular senescence evasion and cancer-related inflammation.

    PubMed

    Bian, Y; Hall, B; Sun, Z-J; Molinolo, A; Chen, W; Gutkind, J S; Waes, C V; Kulkarni, A B

    2012-07-12

    The molecular mechanisms that contribute to the initiation and progression of head and neck squamous cell carcinoma (HNSCC) have not been completely delineated. Our observations indicate that defects in the transforming growth factor-β and PI3K/Akt signaling pathways are common in human HNSCCs. Conditional activation of the PI3K/Akt pathway due to Pten deletion in the mouse head and neck epithelia gives rise to hyperproliferation, but only a few lesions progress to HNSCC. However, Pten-deficient mice developed full-penetrance HNSCC in combination with type I TGF-β receptor (Tgfbr1) deletion. Molecular analysis revealed enhanced cell proliferation, decreased apoptosis, and increased expression of CCND1 in the basal layer of the head and neck epithelia, as well as in the tumors of Tgfbr1/Pten double conditional knockout (2cKO) mice. Furthermore, neoplastic transformation involves senescence evasion, and is associated with an increased number of putative cancer stem cells. In addition, the nuclear factor-κB pathway activation, myeloid-derived suppressor cell infiltration, angiogenesis and immune suppression in the tumor microenvironment, all of which are characteristics of human HNSCCs, contribute significantly to head and neck carcinogenesis in 2cKO mice. These tumors display pathology and multiple molecular alterations resembling human HNSCCs. This suggests that the Tgfbr1/Pten 2cKO mouse model is suitable for preclinical intervention, and that it has significant implications in the development of diagnostic cancer biomarkers and effective strategies for prevention and treatment of HNSCCs. PMID:22037217

  17. A functional network of the tumor suppressors APC, hDlg, and PTEN, that relies on recognition of specific PDZ-domains.

    PubMed

    Sotelo, Natalia S; Valiente, Miguel; Gil, Anabel; Pulido, Rafael

    2012-08-01

    APC and PTEN are tumor suppressor proteins that bind through their C-termini to the PDZ domain containing-hDlg scaffolding protein. We have found that co-expression of PTEN and hDlg enhanced the negative regulation of the PI3K/Akt pathway by PTEN, indicating the physiologic importance of these interactions. APC and PTEN share other PDZ domain containing-interacting partners, including the MAGI scaffolding proteins and the MAST family of protein kinases. Mutational analysis revealed that the C-terminal PDZ-binding motifs from APC and PTEN were differentially recognized by distinct PDZ domains. APC bound to the three PDZ domains from hDlg, whereas PTEN mainly bound to PDZ-2/hDlg. This indicates the existence of overlapping, but distinct PDZ-domain recognition patterns by APC and PTEN. Furthermore, a ternary complex formed by APC, PTEN, and hDlg was detected, suggesting that hDlg may serve as a platform to bring in proximity APC and PTEN tumor suppressor activities. In line with this, tumor-related mutations targeting the PDZ-2/hDlg domain diminished its interaction with APC and PTEN. Our results expand the PDZ-domain counterparts for the tumor suppressor APC, show that APC and PTEN share PDZ-domain partners but have individual molecular determinants for specific recognition of PDZ domains, and suggest the participation of the tumor suppressors APC, PTEN, and hDlg in PDZ-domain interaction networks which may be relevant in oncogenesis.

  18. Germline Inactivation of PTEN and Dysregulation of the Phosphoinositol-3-Kinase/Akt Pathway Cause Human Lhermitte-Duclos Disease in Adults

    PubMed Central

    Zhou, Xiao-Ping; Marsh, Deborah J.; Morrison, Carl D.; Chaudhury, Abhik R.; Maxwell, Marius; Reifenberger, Guido; Eng, Charis

    2003-01-01

    Lhermitte-Duclos disease (LDD), or dysplastic gangliocytoma of the cerebellum, is an unusual hamartomatous overgrowth disorder. LDD can be familial or, more commonly, sporadic. It has been only recently recognized that LDD may be associated with Cowden syndrome (CS). Over 80% of patients with CS carry germline mutations in PTEN. It remains unclear whether all cases of LDD, even without features of CS, are caused by germline PTEN mutation and whether somatic PTEN mutation occurs in sporadic LDD. We obtained paraffin-embedded LDD lesions from 18 unselected, unrelated patients and performed mutational analysis of PTEN. Overall, 15 (83%) of 18 samples were found to carry a PTEN mutation. All individuals with mutations were adult-onset patients, but the three without mutations were diagnosed at the ages of 1, 3, and 11 years. Germline DNA was available from six adult-onset cases, and all had germline PTEN mutations. Of these six, two had CS features, one did not have CS features, and three were of unknown CS status. Immunohistochemistry revealed that 75% of the LDD samples had complete or partial loss of PTEN expression accompanied by elevated phosphorylated Akt, specifically in the dysplastic gangliocytoma cells. These data suggest that the loss of PTEN function is sufficient to cause LDD. The high frequency and spectrum of germline PTEN mutations in patients ascertaining by LDD alone confirm that LDD is an important defining feature of CS. Individuals with LDD, even without apparent CS features, should be counseled as in CS. PMID:14566704

  19. Roles of the RAF/MEK/ERK and PI3K/PTEN/AKT pathways in malignant transformation and drug resistance.

    PubMed

    McCubrey, James A; Steelman, Linda S; Abrams, Steven L; Lee, John T; Chang, Fumin; Bertrand, Fred E; Navolanic, Patrick M; Terrian, David M; Franklin, Richard A; D'Assoro, Antonio B; Salisbury, Jeffrey L; Mazzarino, Maria Clorinda; Stivala, Franca; Libra, Massimo

    2006-01-01

    doxorubicin and paclitaxel. Raf induced the expression of the drug pump Mdr-1 (a.k.a., Pgp) and the Bcl-2 anti-apoptotic protein. Raf did not appear to induce drug resistance by altering p53/p21Cip-1 expression, whose expression is often linked to regulation of cell cycle progression and drug resistance. Deregulation of the PI3K/PTEN/Akt pathway was associated with resistance to doxorubicin and 4-hydroxyl tamoxifen, a chemotherapeutic drug and estrogen receptor antagonist used in breast cancer therapy. In contrast to the drug-resistant breast cancer cells obtained after overexpression of activated Raf, cells expressing activated Akt displayed altered (decreased) levels of p53/p21Cip-1. Deregulated expression of the central phosphatase in the PI3K/PTEN/Akt pathway led to breast cancer drug resistance. Introduction of mutated forms of PTEN, which lacked lipid phosphatase activity, increased the resistance of the MCF-7 cells to doxorubicin, suggesting that these lipid phosphatase deficient PTEN mutants acted as dominant negative mutants to suppress wild-type PTEN activity. Finally, the PI3K/PTEN/Akt pathway appears to be more prominently involved in prostate cancer drug resistance than the Raf/MEK/ERK pathway. Some advanced prostate cancer cells express elevated levels of activated Akt which may suppress Raf activation. Introduction of activated forms of Akt increased the drug resistance of advanced prostate cancer cells. In contrast, introduction of activated forms of Raf did not increase the drug resistance of the prostate cancer cells. In contrast to the results observed in hematopoietic cells, Raf may normally promote differentiation in prostate cells which is suppressed in advanced prostate cancer due to increased expression of activated Akt arising from PTEN mutation. Thus in advanced prostate cancer it may be advantageous to induce Raf expression to promote differentiation, while in hematopoietic cancers it may be beneficial to inhibit Raf/MEK/ERK-induced proliferation

  20. FGFR and PTEN signaling interact during lens development to regulate cell survival.

    PubMed

    Chaffee, Blake R; Hoang, Thanh V; Leonard, Melissa R; Bruney, Devin G; Wagner, Brad D; Dowd, Joseph Richard; Leone, Gustavo; Ostrowski, Michael C; Robinson, Michael L

    2016-02-15

    Lens epithelial cells express many receptor tyrosine kinases (RTKs) that stimulate PI3K-AKT and RAS-RAF-MEK-ERK intracellular signaling pathways. These pathways ultimately activate the phosphorylation of key cellular transcription factors and other proteins that control proliferation, survival, metabolism, and differentiation in virtually all cells. Among RTKs in the lens, only stimulation of fibroblast growth factor receptors (FGFRs) elicits a lens epithelial cell to fiber cell differentiation response in mammals. Moreover, although the lens expresses three different Fgfr genes, the isolated removal of Fgfr2 at the lens placode stage inhibits both lens cell survival and fiber cell differentiation. Phosphatase and tensin homolog (PTEN), commonly known as a tumor suppressor, inhibits ERK and AKT activation and initiates both apoptotic pathways, and cell cycle arrest. Here, we show that the combined deletion of Fgfr2 and Pten rescues the cell death phenotype associated with Fgfr2 loss alone. Additionally, Pten removal increased AKT and ERK activation, above the levels of controls, in the presence or absence of Fgfr2. However, isolated deletion of Pten failed to stimulate ectopic fiber cell differentiation, and the combined deletion of Pten and Fgfr2 failed to restore differentiation-specific Aquaporin0 and DnaseIIβ expression in the lens fiber cells.

  1. Conditional Inactivation of Pten with EGFR Overexpression in Schwann Cells Models Sporadic MPNST

    PubMed Central

    Keng, Vincent W.; Watson, Adrienne L.; Rahrmann, Eric P.; Li, Hua; Tschida, Barbara R.; Moriarity, Branden S.; Choi, Kwangmin; Rizvi, Tilat A.; Collins, Margaret H.; Wallace, Margaret R.; Ratner, Nancy; Largaespada, David A.

    2012-01-01

    The genetic mechanisms involved in the transformation from a benign neurofibroma to a malignant sarcoma in patients with neurofibromatosis-type-1- (NF1-)associated or sporadic malignant peripheral nerve sheath tumors (MPNSTs) remain unclear. It is hypothesized that many genetic changes are involved in transformation. Recently, it has been shown that both phosphatase and tensin homolog (PTEN) and epidermal growth factor receptor (EGFR) play important roles in the initiation of peripheral nerve sheath tumors (PNSTs). In human MPNSTs, PTEN expression is often reduced, while EGFR expression is often induced. We tested if these two genes cooperate in the evolution of PNSTs. Transgenic mice were generated carrying conditional floxed alleles of Pten, and EGFR was expressed under the control of the 2′,3′-cyclic nucleotide 3′phosphodiesterase (Cnp) promoter and a desert hedgehog (Dhh) regulatory element driving Cre recombinase transgenic mice (Dhh-Cre). Complete loss of Pten and EGFR overexpression in Schwann cells led to the development of high-grade PNSTs. In vitro experiments using immortalized human Schwann cells demonstrated that loss of PTEN and overexpression of EGFR cooperate to increase cellular proliferation and anchorage-independent colony formation. This mouse model can rapidly recapitulate PNST onset and progression to high-grade PNSTs, as seen in sporadic MPNST patients. PMID:23319880

  2. PTEN deficiency in a luminal ErbB-2 mouse model results in dramatic acceleration of mammary tumorigenesis and metastasis.

    PubMed

    Schade, Babette; Rao, Trisha; Dourdin, Nathalie; Lesurf, Robert; Hallett, Michael; Cardiff, Robert D; Muller, William J

    2009-07-10

    Overexpression and/or amplification of the ErbB-2 oncogene as well as inactivation of the PTEN tumor suppressor are two important genetic events in human breast carcinogenesis. To address the biological impact of conditional inactivation of PTEN on ErbB-2-induced mammary tumorigenesis, we generated a novel transgenic mouse model that utilizes the murine mammary tumor virus (MMTV) promoter to directly couple expression of activated ErbB-2 and Cre recombinase to the same mammary epithelial cell (MMTV-NIC). Disruption of PTEN in the mammary epithelium of the MMTV-NIC model system dramatically accelerated the formation of multifocal and highly metastatic mammary tumors, which exhibited homogenous pathology. PTEN-deficient/NIC-induced tumorigenesis was associated with an increase in angiogenesis. Moreover, inactivation of PTEN in the MMTV-NIC mouse model resulted in hyperactivation of the phosphatidylinositol 3'-kinase/Akt signaling pathway. However, like the parental strain, tumors obtained from PTEN-deficient/NIC mice displayed histopathological and molecular features of the luminal subtype of primary human breast cancer. Taken together, our findings provide important implications in understanding the molecular determinants of mammary tumorigenesis driven by PTEN deficiency and ErbB-2 activation and could provide a valuable tool for testing the efficacy of therapeutic strategies that target these critical signaling pathways.

  3. Power of PTEN/AKT: Molecular switch between tumor suppressors and oncogenes

    PubMed Central

    XIE, YINGQIU; NAIZABEKOV, SANZHAR; CHEN, ZHANLIN; TOKAY, TURSONJAN

    2016-01-01

    An increasing amount of evidence has shown that tumor suppressors can become oncogenes, or vice versa, but the mechanism behind this is unclear. Recent findings have suggested that phosphatase and tensin homolog (PTEN) is one of the powerful switches for the conversion between tumor suppressors and oncogenes. PTEN regulates a number of cellular processes, including cell death and proliferation, through the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway. Furthermore, a number of studies have suggested that PTEN deletions may alter various functions of certain tumor suppressor and oncogenic proteins. The aim of the present review was to analyze specific cases driven by PTEN loss/AKT activation, including aberrant signaling pathways and novel drug targets for clinical application in personalized medicine. The findings illustrate how PTEN loss and/or AKT activation switches MDM2-dependent p53 downregulation, and induces conversion between oncogene and tumor suppressor in enhancer of zeste homolog 2, BTB domain-containing 7A, alternative reading frame 2, p27 and breast cancer 1, early onset, through multiple mechanisms. This review highlights the genetic basis of complex drug targets and provides insights into the rationale of precision cancer therapy. PMID:27347153

  4. Reciprocal positive regulation between TRPV6 and NUMB in PTEN-deficient prostate cancer cells

    SciTech Connect

    Kim, Sung-Young; Hong, Chansik; Wie, Jinhong; Kim, Euiyong; Kim, Byung Joo; Ha, Kotdaji; Cho, Nam-Hyuk; Kim, In-Gyu; Jeon, Ju-Hong; So, Insuk

    2014-04-25

    Highlights: • TRPV6 interacts with tumor suppressor proteins. • Numb has a selective effect on TRPV6, depending on the prostate cancer cell line. • PTEN is a novel regulator of TRPV6–Numb complex. - Abstract: Calcium acts as a second messenger and plays a crucial role in signaling pathways involved in cell proliferation. Recently, calcium channels related to calcium influx into the cytosol of epithelial cells have attracted attention as a cancer therapy target. Of these calcium channels, TRPV6 is overexpressed in prostate cancer and is considered an important molecule in the process of metastasis. However, its exact role and mechanism is unclear. NUMB, well-known tumor suppressor gene, is a novel interacting partner of TRPV6. We show that NUMB and TRPV6 have a reciprocal positive regulatory relationship in PC-3 cells. We repeated this experiment in two other prostate cancer cell lines, DU145 and LNCaP. Interestingly, there were no significant changes in TRPV6 expression following NUMB knockdown in DU145. We revealed that the presence or absence of PTEN was the cause of NUMB–TRPV6 function. Loss of PTEN caused a positive correlation of TRPV6–NUMB expression. Collectively, we determined that PTEN is a novel interacting partner of TRPV6 and NUMB. These results demonstrated a novel relationship of NUMB–TRPV6 in prostate cancer cells, and show that PTEN is a novel regulator of this complex.

  5. Therapeutic targeting of cancers with loss of PTEN function

    PubMed Central

    Dillon, Lloye M.; Miller, Todd W.

    2015-01-01

    Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is one of the most frequently disrupted tumor suppressors in cancer. The lipid phosphatase activity of PTEN antagonizes the phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR pathway to repress tumor cell growth and survival. In the nucleus, PTEN promotes chromosome stability and DNA repair. Consequently, loss of PTEN function increases genomic instability. PTEN deficiency is caused by inherited germline mutations, somatic mutations, epigenetic and transcriptional silencing, post-translational modifications, and protein-protein interactions. Given the high frequency of PTEN deficiency across cancer subtypes, therapeutic approaches that exploit PTEN loss-of-function could provide effective treatment strategies. Herein, we discuss therapeutic strategies aimed at cancers with loss of PTEN function, and the challenges involved in treating patients afflicted with such cancers. We review preclinical and clinical findings, and highlight novel strategies under development to target PTEN-deficient cancers. PMID:24387334

  6. PRL-3 promotes the peritoneal metastasis of gastric cancer through the PI3K/Akt signaling pathway by regulating PTEN.

    PubMed

    Xiong, Jianbo; Li, Zhengrong; Zhang, Yang; Li, Daojiang; Zhang, Guoyang; Luo, Xianshi; Jie, Zhigang; Liu, Yi; Cao, Yi; Le, Zhibiao; Tan, Shengxing; Zou, Wenyu; Gong, Peitao; Qiu, Lingyu; Li, Yuanyuan; Wang, Huan; Chen, Heping

    2016-10-01

    Peritoneal metastasis is the most frequent cause of death in patients with advanced gastric carcinoma (GC). The phosphatase of regenerating liver-3 (PRL-3) is recognized as an oncogene and plays an important role in GC peritoneal metastasis. However, the mechanism of how PRL-3 regulates GC invasion and metastasis is unknown. In the present study, we found that PRL-3 presented with high expression in GC with peritoneal metastasis, but phosphatase and tensin homologue (PTEN) was weakly expressed. The p-PTEN/PTEN ratio was also higher in GC with peritoneal metastasis than that in the normal gastric tissues. We also found the same phenomenon when comparing the gastric mucosa cell line with the GC cell lines. After constructing a wild-type and a mutant-type plasmid without enzyme activity and transfecting them into GC SGC7901 cells, we showed that only PRL-3 had enzyme activity to downregulate PTEN and cause PTEN phosphorylation. The results also showed that PRL-3 increased the expression levels of MMP-2/MMP-9 and promoted the migration and invasion of the SGC7901 cells. Knockdown of PRL-3 decreased the expression levels of MMP-2/MMP-9 significantly, which further inhibited the migration and invasion of the GC cells. PRL-3 also increased the expression ratio of p-Akt/Akt, which indicated that PRL-3 may mediate the PI3K/Akt pathway to promote GC metastasis. When we transfected the PTEN siRNA plasmid into the PRL-3 stable low expression GC cells, the expression of p-Akt, MMP-2 and MMP-9 was reversed. In conclusion, our results provide a bridge between PRL-3 and PTEN; PRL-3 decreased the expression of PTEN as well as increased the level of PTEN phosphorylation and inactivated it, consequently activating the PI3K/Akt signaling pathway, and upregulating MMP-2/MMP-9 expression to promote GC cell peritoneal metastasis.

  7. PRL-3 promotes the peritoneal metastasis of gastric cancer through the PI3K/Akt signaling pathway by regulating PTEN

    PubMed Central

    Xiong, Jianbo; Li, Zhengrong; Zhang, Yang; Li, Daojiang; Zhang, Guoyang; Luo, Xianshi; Jie, Zhigang; Liu, Yi; Cao, Yi; Le, Zhibiao; Tan, Shengxing; Zou, Wenyu; Gong, Peitao; Qiu, Lingyu; Li, Yuanyuan; Wang, Huan; Chen, Heping

    2016-01-01

    Peritoneal metastasis is the most frequent cause of death in patients with advanced gastric carcinoma (GC). The phosphatase of regenerating liver-3 (PRL-3) is recognized as an oncogene and plays an important role in GC peritoneal metastasis. However, the mechanism of how PRL-3 regulates GC invasion and metastasis is unknown. In the present study, we found that PRL-3 presented with high expression in GC with peritoneal metastasis, but phosphatase and tensin homologue (PTEN) was weakly expressed. The p-PTEN/PTEN ratio was also higher in GC with peritoneal metastasis than that in the normal gastric tissues. We also found the same phenomenon when comparing the gastric mucosa cell line with the GC cell lines. After constructing a wild-type and a mutant-type plasmid without enzyme activity and transfecting them into GC SGC7901 cells, we showed that only PRL-3 had enzyme activity to downregulate PTEN and cause PTEN phosphorylation. The results also showed that PRL-3 increased the expression levels of MMP-2/MMP-9 and promoted the migration and invasion of the SGC7901 cells. Knockdown of PRL-3 decreased the expression levels of MMP-2/MMP-9 significantly, which further inhibited the migration and invasion of the GC cells. PRL-3 also increased the expression ratio of p-Akt/Akt, which indicated that PRL-3 may mediate the PI3K/Akt pathway to promote GC metastasis. When we transfected the PTEN siRNA plasmid into the PRL-3 stable low expression GC cells, the expression of p-Akt, MMP-2 and MMP-9 was reversed. In conclusion, our results provide a bridge between PRL-3 and PTEN; PRL-3 decreased the expression of PTEN as well as increased the level of PTEN phosphorylation and inactivated it, consequently activating the PI3K/Akt signaling pathway, and upregulating MMP-2/MMP-9 expression to promote GC cell peritoneal metastasis. PMID:27572739

  8. Prostate tumorigenesis induced by PTEN deletion involves estrogen receptor β repression.

    PubMed

    Mak, Paul; Li, Jiarong; Samanta, Sanjoy; Chang, Cheng; Jerry, D Joseph; Davis, Roger J; Leav, Irwin; Mercurio, Arthur M

    2015-03-31

    The role of ERβ in prostate cancer is unclear, although loss of ERβ is associated with aggressive disease. Given that mice deficient in ERβ do not develop prostate cancer, we hypothesized that ERβ loss occurs as a consequence of tumorigenesis caused by other oncogenic mechanisms and that its loss is necessary for tumorigenesis. In support of this hypothesis, we found that ERβ is targeted for repression in prostate cancer caused by PTEN deletion and that loss of ERβ is important for tumor formation. ERβ transcription is repressed by BMI-1, which is induced by PTEN deletion and important for prostate tumorigenesis. This finding provides a mechanism for how ERβ expression is regulated in prostate cancer. Repression of ERβ contributes to tumorigenesis because it enables HIF-1/VEGF signaling that sustains BMI-1 expression. These data reveal a positive feedback loop that is activated in response to PTEN loss and sustains BMI-1.

  9. MiRNA-10a is upregulated in NSCLC and may promote cancer by targeting PTEN

    PubMed Central

    Yu, Tao; Liu, Lei; Li, Jing; Yan, Mingxia; Lin, Hechun; Liu, Ying; Chu, Dandan; Tu, Hong; Gu, Aiqin; Yao, Ming

    2015-01-01

    MicroRNAs (miRNAs) are involved in human cancer including non-small cell lung cancer (NSCLC). In this study, we compared miRNA expression microarray of SPC-A-1sci (high metastatic) and SPC-A-1 (weakly metastatic) cells. We found that miRNA-10a was up-regulated in NSCLC compared with corresponding normal tissues. High expression of miR-10a was associated with tumor node metastasis and lymph node metastasis. Furthermore, overexpression of miR-10a promoted NSCLC cell proliferation, migration and invasion in vitro. We found that PTEN was a direct target of miR-10a in NSCLC. Also miR-10a activated the PTEN/AKT/ERK pathway. We suggest that miR-10a contributes to NSCLC by targeting PTEN. PMID:26317552

  10. PI3K/Akt and Stat3 signaling regulated by PTEN control of the cancer stem cell population, proliferation and senescence in a glioblastoma cell line.

    PubMed

    Moon, Seok-Ho; Kim, Dae-Kwan; Cha, Young; Jeon, Iksoo; Song, Jihwan; Park, Kyung-Soon

    2013-03-01

    Malignant gliomas are the most common primary brain tumor in adults. A number of genes have been implicated in glioblastoma including mutation and deletion of PTEN. PTEN is a regulator of PI3K-mediated Akt signaling pathways and has been recognized as a therapeutic target in glioblastoma. To achieve potent therapeutic inhibition of the PI3K-Akt pathway in glioblastoma, it is essential to understand the interplay between the regulators of its activation. Here, ectopic expression of PTEN in the U-87MG human glioblastoma-astrocytoma cell line is shown to result in the depletion of glioblastoma stem cells (GSCs) and to cause growth retardation and senescence. These effects are likely to be associated with PTEN-mediated cooperative perturbation of Akt and Stat3 signals. Using an in vivo rat model of glioblastoma, we showed that PTEN-overexpressing U-87MG cells failed to induce tumor formation, while untreated U-87MG cells did so. Furthermore, cells expressing the phosphorylated form of Stat3 were completely absent from the brain of rats implanted with PTEN-overexpressing U-87MG cells. Based on these results, PTEN appears to function as a crucial inhibitor of GSCs and as an inducer of senescence, suggesting that functional enhancement of the PTEN pathway will be useful to provide a therapeutic strategy for targeting glioblastoma. PMID:23314408

  11. Administration of a PTEN inhibitor BPV(pic) attenuates early brain injury via modulating AMPA receptor subunits after subarachnoid hemorrhage in rats.

    PubMed

    Chen, Yujie; Luo, Chunxia; Zhao, Mingyue; Li, Qiang; Hu, Rong; Zhang, John H; Liu, Zhi; Feng, Hua

    2015-02-19

    The aim of this study was to investigate whether the phosphatase and tensin homolog deleted on chromosome ten (PTEN) inhibitor dipotassium bisperoxo(pyridine-2-carboxyl) oxovanadate (BPV(pic)) attenuates early brain injury by modulating α-amino-3-hydroxy-5-methyl-4-isoxa-zolep-propionate (AMPA) receptor subunits after subarachnoid hemorrhage (SAH). A standard intravascular perforation model was used to produce the experimental SAH in Sprague-Dawley rats. BPV(pic) treatment (0.2mg/kg) was evaluated for effects on neurological score, brain water content, Evans blue extravasation, hippocampal neuronal death and AMPA receptor subunits alterations after SAH. We found that BPV(pic) is effective in attenuating BBB disruption, lowering edema, reducing hippocampal neural death and improving neurological outcomes. In addition, the AMPA receptor subunit GluR1 protein expression at cytomembrane was downregulated, whereas the expression of GluR2 and GluR3 was upregulated after BPV(pic) treatment. Our results suggest that PTEN inhibited by BPV(pic) plays a neuroprotective role in SAH pathophysiology, possibly by alterations in glutamate AMPA receptor subunits.

  12. PTEN inhibitors: an evaluation of current compounds.

    PubMed

    Spinelli, Laura; Lindsay, Yvonne E; Leslie, Nicholas R

    2015-01-01

    Small molecule inhibitors of many classes of enzymes, including phosphatases, have widespread use as experimental tools and as therapeutics. Efforts to develop inhibitors against the lipid phosphatase and tumour suppressor, PTEN, was for some time limited by concerns that their use as therapy could result in increased risk of cancer. However, the accumulation of evidence that short term PTEN inhibition may be valuable in conditions such as nerve injury has raised interest. Here we investigate the inhibition of PTEN by four available PTEN inhibitors, bpV(phen), bpV(pic), VO-OHpic and SF1670 and compared this inhibition with that of only 3 other related enzymes, the tyrosine phosphatase SHP1 and the phosphoinositide phosphatases INPP4A and INPP4B. Even with this very small number of comparators, for all compounds, inhibition of multiple enzymes was observed and with all three vanadate compounds, this was similar or more potent than the inhibition of PTEN. In particular, the bisperoxovanadate compounds were found to inhibit PTEN poorly in the presence of reducing agents including the cellular redox buffer glutathione.

  13. Identification of novel PTEN-binding partners: PTEN interaction with fatty acid binding protein FABP4.

    PubMed

    Gorbenko, O; Panayotou, G; Zhyvoloup, A; Volkova, D; Gout, I; Filonenko, V

    2010-04-01

    PTEN is a tumor suppressor with dual protein and lipid-phosphatase activity, which is frequently deleted or mutated in many human advanced cancers. Recent studies have also demonstrated that PTEN is a promising target in type II diabetes and obesity treatment. Using C-terminal PTEN sequence in pEG202-NLS as bait, yeast two-hybrid screening on Mouse Embryo, Colon Cancer, and HeLa cDNA libraries was carried out. Isolated positive clones were validated by mating assay and identified through automated DNA sequencing and BLAST database searches. Sequence analysis revealed a number of PTEN-binding proteins linking this phosphatase to a number of different signaling cascades, suggesting that PTEN may perform other functions besides tumor-suppressing activity in different cell types. In particular, the interplay between PTEN function and adipocyte-specific fatty-acid-binding protein FABP4 is of notable interest. The demonstrable tautology of PTEN to FABP4 suggested a role for this phosphatase in the regulation of lipid metabolism and adipocyte differentiation. This interaction was further studied using coimmunoprecipitation and gel-filtration assays. Finally, based on Biacore assay, we have calculated the K(D) of PTEN-FABP4 complex, which is around 2.8 microM.

  14. MicroRNA-21 Contributes to Liver Regeneration by Targeting PTEN

    PubMed Central

    Chen, Xiaoyu; Song, Meiyi; Chen, Wei; Dimitrova-Shumkovska, Jasmina; Zhao, Yingying; Cao, Yan; Song, Yang; Yang, Wenzhuo; Wang, Fei; Xiang, Yang; Yang, Changqing

    2016-01-01

    Background Multiple microRNAs (miRNAs, miRs), including miR-21, have been documented to be critical regulators of liver regeneration, but the mechanism underlying their roles in hepatocyte proliferation and cell cycle progression is still far from understood. Material/Methods miR-21 levels were determined using qRT-PCRs in mouse livers at 48 h after 70% partial hepatectomy (PH-48 h). Cell proliferation was determined by use of a cell-counting kit-8 (CCK-8), EdU incorporation staining, and flow cytometry. Phosphatase and tensin homolog (PTEN) expressions were determined using qRT-PCR and Western blot analysis. PTEN siRNA was used to perform the rescue experiment. Results A marked upregulation of miR-21 was observed in mouse livers at 48 h after 70% partial hepatectomy (PH-48 h) compared to 0 h after PH (PH-0 h). Overexpression of miR-21 was associated with increased proliferation and a rapid G1-to-S phase transition of the cell cycle in BNL CL.2 normal liver cells in vitro. In addition, we showed that PTEN expression was inversely correlated with miR-21 in BNL CL.2 cells and demonstrated that PTEN expression is lower in mouse livers at PH-48 h. Moreover, the presence of PTEN siRNA significantly abolished the suppressive effect of miR-21 inhibitor on hepatocyte proliferation. Conclusions miR-21 overexpression contributes to liver regeneration and hepatocyte proliferation by targeting PTEN. Upregulation of miR-21 might be a useful therapeutic strategy to promote liver regeneration. PMID:26744142

  15. Role of PTEN in TNFα induced insulin resistance

    SciTech Connect

    Bulger, David A.; Conley, Jermaine; Conner, Spencer H.; Majumdar, Gipsy; Solomon, Solomon S.

    2015-06-05

    Aims/hypothesis: PTEN may play a reversible role in TNFα induced insulin resistance, which has been linked to obesity-associated insulin resistance (IR). Methods: Western blots for PTEN and p-Akt were performed on H-411E liver cells incubated with insulin, TNFα, and in selected experiments VO-OHpic vanadium complex in the presence and absence of PTEN siRNA. Total PTEN was compared to β-actin loading control and p-Akt was compared to total Akt. Results: Western blot and Real Time RT-PCR experiments showed increased PTEN after TNFα treatment (p = 0.04); slightly decreased PTEN after insulin treatment; and slightly increased PTEN after insulin + TNFα treatment. PTEN siRNA markedly inhibited the TNFα-induced increase in PTEN (p < 0.01) without significantly changing the p-Akt levels. The vanadium complex, exhibiting insulin-like effects, also significantly prevented the TNFα-induced increase in PTEN. Combining insulin and VO-OHpic was additive, providing both proof of concept and insight into mechanism. Discussion: The PTEN increase due to TNFα treatment was reversible by both PTEN siRNA knockdown and VO-OHpic treatment. Thus, PTEN is identified as a potential new therapeutic target for reducing IR in Type 2 DM. - Highlights: • TNFα treatment induced a significant increase in PTEN in H-411E liver cells. • PTEN siRNA knockdown prevented this effect. • VO-OHpic (vanadium complex) treatment, like insulin, decreased PTEN protein levels. • Thus, PTEN is identified as a potential therapeutic target in DM Type 2.

  16. Role of PTEN in TNF Induced Insulin Resistance

    PubMed Central

    Bulger, David A; Conley, Jermaine; Conner, Spencer H; Majumdar, Gipsy; Solomon, Solomon S

    2015-01-01

    Aims/hypothesis PTEN may play a reversible role in TNFα induced insulin resistance, which has been linked to obesity-associated insulin resistance (IR). Methods Western blots for PTEN and p-Akt were performed on H-411E liver cells incubated with insulin, TNFα, and in selected experiments VO-OHpic vanadium complex in the presence and absence of PTEN siRNA. Total PTEN was compared to β-actin loading control and p-Akt was compared to total Akt. Results Western blot and Real Time RT-PCR experiments showed increased PTEN after TNFα treatment (p = 0.04); slightly decreased PTEN after insulin treatment; and slightly increased PTEN after insulin + TNFα treatment. PTEN siRNA markedly inhibited the TNFα-induced increase in PTEN (p < 0.01) without significantly changing the p-Akt levels. The vanadium complex, exhibiting insulin-like effects, also significantly prevented the TNFα-induced increase in PTEN. Combining insulin and VO-OHpic was additive, providing both proof of concept and insight into mechanism. Discussion The PTEN increase due to TNFα treatment was reversible by both PTEN siRNA knockdown and VO-OHpic treatment. Thus, PTEN is identified as a potential new therapeutic target for reducing IR in Type 2 DM. PMID:25918024

  17. Alterations in vascular gene expression in invasive breast carcinoma.

    PubMed

    Parker, Belinda S; Argani, Pedram; Cook, Brian P; Liangfeng, Han; Chartrand, Scott D; Zhang, Mindy; Saha, Saurabh; Bardelli, Alberto; Jiang, Yide; St Martin, Thia B; Nacht, Mariana; Teicher, Beverly A; Klinger, Katherine W; Sukumar, Saraswati; Madden, Stephen L

    2004-11-01

    The molecular signature that defines tumor microvasculature will likely provide clues as to how vascular-dependent tumor proliferation is regulated. Using purified endothelial cells, we generated a database of gene expression changes accompanying vascular proliferation in invasive breast cancer. In contrast to normal mammary vasculature, invasive breast cancer vasculature expresses extracellular matrix and surface proteins characteristic of proliferating and migrating endothelial cells. We define and validate the up-regulated expression of VE-cadherin and osteonectin in breast tumor vasculature. In contrast to other tumor types, invasive breast cancer vasculature induced a high expression level of specific transcription factors, including SNAIL1 and HEYL, that may drive gene expression changes necessary for breast tumor neovascularization. We demonstrate the expression of HEYL in tumor endothelial cells and additionally establish the ability of HEYL to both induce proliferation and attenuate programmed cell death of primary endothelial cells in vitro. We also establish that an additional intracellular protein and previously defined metastasis-associated gene, PRL3, appears to be expressed predominately in the vasculature of invasive breast cancers and is able to enhance the migration of endothelial cells in vitro. Together, our results provide unique insights into vascular regulation in breast tumors and suggest specific roles for genes in driving tumor angiogenesis. PMID:15520192

  18. Pten and EphB4 regulate the establishment of perisomatic inhibition in mouse visual cortex

    PubMed Central

    Baohan, Amy; Ikrar, Taruna; Tring, Elaine; Xu, Xiangmin; Trachtenberg, Joshua T.

    2016-01-01

    Perisomatic inhibition of pyramidal neurons is established by fast-spiking, parvalbumin-expressing interneurons (PV cells). Failure to assemble adequate perisomatic inhibition is thought to underlie the aetiology of neurological dysfunction in seizures, autism spectrum disorders and schizophrenia. Here we show that in mouse visual cortex, strong perisomatic inhibition does not develop if PV cells lack a single copy of Pten. PTEN signalling appears to drive the assembly of perisomatic inhibition in an experience-dependent manner by suppressing the expression of EphB4; PV cells hemizygous for Pten show an ∼2-fold increase in expression of EphB4, and over-expression of EphB4 in adult PV cells causes a dismantling of perisomatic inhibition. These findings implicate a molecular disinhibitory mechanism driving the establishment of perisomatic inhibition whereby visual experience enhances Pten signalling, resulting in the suppression of EphB4 expression; this relieves a native synaptic repulsion between PV cells and pyramidal neurons, thereby promoting the assembly of perisomatic inhibition. PMID:27611660

  19. Pten and EphB4 regulate the establishment of perisomatic inhibition in mouse visual cortex.

    PubMed

    Baohan, Amy; Ikrar, Taruna; Tring, Elaine; Xu, Xiangmin; Trachtenberg, Joshua T

    2016-01-01

    Perisomatic inhibition of pyramidal neurons is established by fast-spiking, parvalbumin-expressing interneurons (PV cells). Failure to assemble adequate perisomatic inhibition is thought to underlie the aetiology of neurological dysfunction in seizures, autism spectrum disorders and schizophrenia. Here we show that in mouse visual cortex, strong perisomatic inhibition does not develop if PV cells lack a single copy of Pten. PTEN signalling appears to drive the assembly of perisomatic inhibition in an experience-dependent manner by suppressing the expression of EphB4; PV cells hemizygous for Pten show an ∼2-fold increase in expression of EphB4, and over-expression of EphB4 in adult PV cells causes a dismantling of perisomatic inhibition. These findings implicate a molecular disinhibitory mechanism driving the establishment of perisomatic inhibition whereby visual experience enhances Pten signalling, resulting in the suppression of EphB4 expression; this relieves a native synaptic repulsion between PV cells and pyramidal neurons, thereby promoting the assembly of perisomatic inhibition. PMID:27611660

  20. Targeted disruption of Pten in ovarian granulosa cells enhances ovulation and extends the life span of luteal cells.

    PubMed

    Fan, Heng-Yu; Liu, Zhilin; Cahill, Nicola; Richards, JoAnne S

    2008-09-01

    FSH activates the phosphatidylinositol-3 kinase (PI3K)/acute transforming retrovirus thymoma protein kinase pathway and thereby enhances granulosa cell differentiation in culture. To identify the physiological role of the PI3K pathway in vivo we disrupted the PI3K suppressor, Pten, in developing ovarian follicles. To selectively disrupt Pten expression in granulosa cells, Ptenfl/fl mice were mated with transgenic mice expressing cAMP response element recombinase driven by Cyp19 promoter (Cyp19-Cre). The resultant Pten mutant mice were fertile, ovulated more oocytes, and produced moderately more pups than control mice. These physiological differences in the Pten mutant mice were associated with hyperactivation of the PI3K/acute transforming retrovirus thymoma protein kinase pathway, decreased susceptibility to apoptosis, and increased proliferation of mutant granulosa cells. Strikingly, corpora lutea of the Pten mutant mice persisted longer than those of control mice. Although the follicular and luteal cell steroidogenesis in Ptenfl/fl;Cyp19-Cre mice was similar to controls, viable nonsteroidogenic luteal cells escaped structural luteolysis. These findings provide the novel evidence that Pten impacts the survival/life span of granulosa/luteal cells and that its loss not only results in the facilitated ovulation but also in the persistence of nonsteroidogenic luteal structures in the adult mouse ovary.

  1. Targeted Disruption of Pten in Ovarian Granulosa Cells Enhances Ovulation and Extends the Life Span of Luteal Cells

    PubMed Central

    Fan, Heng-Yu; Liu, Zhilin; Cahill, Nicola; Richards, JoAnne S.

    2008-01-01

    FSH activates the phosphatidylinositol-3 kinase (PI3K)/acute transforming retrovirus thymoma protein kinase pathway and thereby enhances granulosa cell differentiation in culture. To identify the physiological role of the PI3K pathway in vivo we disrupted the PI3K suppressor, Pten, in developing ovarian follicles. To selectively disrupt Pten expression in granulosa cells, Ptenfl/fl mice were mated with transgenic mice expressing cAMP response element recombinase driven by Cyp19 promoter (Cyp19-Cre). The resultant Pten mutant mice were fertile, ovulated more oocytes, and produced moderately more pups than control mice. These physiological differences in the Pten mutant mice were associated with hyperactivation of the PI3K/acute transforming retrovirus thymoma protein kinase pathway, decreased susceptibility to apoptosis, and increased proliferation of mutant granulosa cells. Strikingly, corpora lutea of the Pten mutant mice persisted longer than those of control mice. Although the follicular and luteal cell steroidogenesis in Ptenfl/fl;Cyp19-Cre mice was similar to controls, viable nonsteroidogenic luteal cells escaped structural luteolysis. These findings provide the novel evidence that Pten impacts the survival/life span of granulosa/luteal cells and that its loss not only results in the facilitated ovulation but also in the persistence of nonsteroidogenic luteal structures in the adult mouse ovary. PMID:18606860

  2. PTEN/MMAC1/TEP1 suppresses the tumorigenicity and induces G1 cell cycle arrest in human glioblastoma cells

    PubMed Central

    Li, Da-Ming; Sun, Hong

    1998-01-01

    PTEN/MMAC1/TEP1 is a tumor suppressor that possesses intrinsic phosphatase activity. Deletions or mutations of its encoding gene are associated with a variety of human cancers. However, very little is known about the molecular mechanisms by which this important tumor suppressor regulates cell growth. Here, we show that PTEN expression potently suppressed the growth and tumorigenicity of human glioblastoma U87MG cells. The growth suppression activity of PTEN was mediated by its ability to block cell cycle progression in the G1 phase. Such an arrest correlated with a significant increase of the cell cycle kinase inhibitor p27KIP1 and a concomitant decrease in the activities of the G1 cyclin-dependent kinases. PTEN expression also led to the inhibition of Akt/protein kinase B, a serine-threonine kinase activated by the phosphatidylinositol 3-kinase (PI 3-kinase) signaling pathway. In addition, the effect of PTEN on p27KIP1 and the cell cycle can be mimicked by treatment of U87MG cells with LY294002, a selective inhibitor of PI 3-kinase. Taken together, our studies suggest that the PTEN tumor suppressor modulates G1 cell cycle progression through negatively regulating the PI 3-kinase/Akt signaling pathway, and one critical target of this signaling process is the cyclin-dependent kinase inhibitor p27KIP1. PMID:9860981

  3. Arabidopsis gene expression patterns are altered during spaceflight

    NASA Astrophysics Data System (ADS)

    Paul, Anna-Lisa; Popp, Michael P.; Gurley, William B.; Guy, Charles; Norwood, Kelly L.; Ferl, Robert J.

    The exposure of Arabidopsis thaliana (Arabidopsis) plants to spaceflight environments results in differential gene expression. A 5-day mission on orbiter Columbia in 1999 (STS-93) carried transgenic Arabidopsis plants engineered with a transgene composed of the alcohol dehydrogenase (Adh) gene promoter linked to the β-Glucuronidase (GUS) reporter gene. The plants were used to evaluate the effects of spaceflight on gene expression patterns initially by using the Adh/GUS transgene to address specifically the possibility that spaceflight induces a hypoxic stress response (Paul, A.L., Daugherty, C.J., Bihn, E.A., Chapman, D.K., Norwood, K.L., Ferl, R.J., 2001. Transgene expression patterns indicate that spaceflight affects stress signal perception and transduction in arabidopsis, Plant Physiol. 126, 613-621). As a follow-on to the reporter gene analysis, we report here the evaluation of genome-wide patterns of native gene expression within Arabidopsis shoots utilizing the Agilent DNA array of 21,000 Arabidopsis genes. As a control for the veracity of the array analyses, a selection of genes was further characterized with quantitative Real-Time RT PCR (ABI - Taqman®). Comparison of the patterns of expression for arrays probed with RNA isolated from plants exposed to spaceflight compared to RNA isolated from ground control plants revealed 182 genes that were differentially expressed in response to the spaceflight mission by more than 4-fold, and of those only 50 genes were expressed at levels chosen to support a conservative change call. None of the genes that are hallmarks of hypoxic stress were induced to this level. However, genes related to heat shock were dramatically induced - but in a pattern and under growth conditions that are not easily explained by elevated temperatures. These gene expression data are discussed in light of current models for plant responses to the spaceflight environment and with regard to potential future spaceflight experiment

  4. Conjugated linoleic acids attenuate FSH- and IGF1-stimulated cell proliferation; IGF1, GATA4, and aromatase expression; and estradiol-17β production in buffalo granulosa cells involving PPARγ, PTEN, and PI3K/Akt.

    PubMed

    Sharma, Isha; Singh, Dheer

    2012-09-01

    Conjugated linoleic acid (CLA) has drawn much interest in last two decades in the area ranging from anticancer activity to obesity. A number of research papers have been published recently with regard to CLA's additional biological functions as reproductive benefits. However, not much is known how this mixture of isomeric compounds mediates its beneficial effects particularly on fertility. In this study, we demonstrated the cross talk between downstream signaling of CLA and important hormone regulators of endocrine system, i.e. FSH and IGF1, on buffalo granulosa cell function (proliferation and steroidogenesis). Experiments were performed in primary serum-free buffalo granulosa cell culture, where cells were incubated with CLA in combination with FSH (25 ng/ml) and IGF1 (50  ng/ml). Results showed that 10 μM CLA inhibits FSH- and IGF1-induced granulosa cell proliferation; aromatase, GATA4, and IGF1 mRNA; and estradiol-17β production. Western blot analysis of total cell lysates revealed that CLA intervenes the IGF1 signaling by decreasing p-Akt. In addition, CLA was found to upregulate peroxisome proliferator-activated receptor-gamma (PPARG) and phosphatase and tensin homolog (PTEN) level in granulosa cells. Further study using PPARG- and PTEN-specific inhibitors supports the potential role of CLA in granulosa cell proliferation and steroidogenesis involving PPARG, PTEN, and PI3K/Akt pathway.

  5. Altered Expression of Oxidative Metabolism Related Genes in Cholangiocarcinomas.

    PubMed

    Aukkanimart, Ratchadawan; Boonmars, Thidarut; Juasook, Amornrat; Sriraj, Pranee; Boonjaraspinyo, Sirintip; Wu, Zhiliang; Laummuanwai, Porntip; Pairojkul, Chawalit; Khuntikeo, Narong; Rattanasuwan, Panaratana

    2015-01-01

    Cholangiocarcinoma (CCA) is a rare but highly fatal cancer for which the molecular mechanisms and diagnostic markers are obscure. We therefore investigated the kinetic expression of isocitrate dehydrogenase-1 (IDH1), isocitrate dehydrogenase-2 (IDH2) and homogentisate 1,2-dioxygenase (HGD) during the tumorigenesis of O. viverrini infection-associated CCA in an animal model, and confirmed down-regulation of expression in human cases of opisthorchiasis-associated CCA through real time PCR. Kinetic expression of HGD, IDH1 and IDH2 in the animal model of O. viverrini infection-induced CCA was correlated with human CCA cases. In the animal model, expression of HGD was decreased at all time points (p<0.01) and expression of both IDH1 and IDH2 was decreased in the CCA group. In human cases, expression of HGD, IDH1 and IDH2 was decreased more than 2 fold in 55 cases (70.5%), 25 cases (32.1%) and 24 cases (30.8%) respectively. The present study suggests that reduction of HGD, IDH1 and IDH2 may be involve in cholangiocarcinoma genesis and may be useful for molecular diagnosis. PMID:26320466

  6. Combined deletion of Pten and p53 in mammary epithelium accelerates triple-negative breast cancer with dependency on eEF2K

    PubMed Central

    Liu, Jeff C; Voisin, Veronique; Wang, Sharon; Wang, Dong-Yu; Jones, Robert A; Datti, Alessandro; Uehling, David; Al-awar, Rima; Egan, Sean E; Bader, Gary D; Tsao, Ming; Mak, Tak W; Zacksenhaus, Eldad

    2014-01-01

    The tumor suppressors Pten and p53 are frequently lost in breast cancer, yet the consequences of their combined inactivation are poorly understood. Here, we show that mammary-specific deletion of Pten via WAP-Cre, which targets alveolar progenitors, induced tumors with shortened latency compared to those induced by MMTV-Cre, which targets basal/luminal progenitors. Combined Pten-p53 mutations accelerated formation of claudin-low, triple-negative-like breast cancer (TNBC) that exhibited hyper-activated AKT signaling and more mesenchymal features relative to Pten or p53 single-mutant tumors. Twenty-four genes that were significantly and differentially expressed between WAP-Cre:Pten/p53 and MMTV-Cre:Pten/p53 tumors predicted poor survival for claudin-low patients. Kinome screens identified eukaryotic elongation factor-2 kinase (eEF2K) inhibitors as more potent than PI3K/AKT/mTOR inhibitors on both mouse and human Pten/p53-deficient TNBC cells. Sensitivity to eEF2K inhibition correlated with AKT pathway activity. eEF2K monotherapy suppressed growth of Pten/p53-deficient TNBC xenografts in vivo and cooperated with doxorubicin to efficiently kill tumor cells in vitro. Our results identify a prognostic signature for claudin-low patients and provide a rationale for using eEF2K inhibitors for treatment of TNBC with elevated AKT signaling. PMID:25330770

  7. Akt and PTEN: new diagnostic markers of non-small cell lung cancer?

    PubMed

    David, O

    2001-01-01

    We are particularly interested in testing the principles of cell proliferation and apoptosis in the microenvironment of human lung cancers with respect to the cell survival protein Akt 1 and PTEN 2. Akt is a cytosolic protein which promotes cell survival by phosphorylative inactivation of targets in apoptotic pathways. Akt has been found to play a role in the survival of experimental cancer cell lines in breast, prostate, ovary, lung and brain tissue. PTEN is a tumor suppressor gene whose protein product is expressed in inverse proportion to phosphorylated Akt in endometrial and breast cancer cell lines. No studies of the diagnostic significance of Akt and PTEN in human lung cancers have been reported.

  8. Coding-independent regulation of the tumor suppressor PTEN by competing endogenous mRNAs

    PubMed Central

    Tay, Yvonne; Kats, Lev; Salmena, Leonardo; Weiss, Dror; Tan, Shen Mynn; Ala, Ugo; Karreth, Florian; Poliseno, Laura; Provero, Paolo; Di Cunto, Ferdinando; Lieberman, Judy; Rigoutsos, Isidore; Pandolfi, Pier Paolo

    2011-01-01

    SUMMARY Here we demonstrate that protein-coding RNA transcripts can crosstalk by competing for common microRNAs, with microRNA response elements as the foundation of this interaction. We have termed such RNA transcripts as competing endogenous RNAs (ceRNAs). We tested this hypothesis in the context of PTEN, a key tumor suppressor whose abundance determines critical outcomes in tumorigenesis. By a combined computational and experimental approach, we identified and validated endogenous protein-coding transcripts that regulate PTEN, antagonize PI3K/AKT signaling and possess growth and tumor suppressive properties. Notably, we also show that these genes display concordant expression patterns with PTEN and copy number loss in cancers. Our study presents a road map for the prediction and validation of ceRNA activity and networks, and thus imparts a trans-regulatory function to protein-coding mRNAs. PMID:22000013

  9. Nuclear PTEN controls DNA repair and sensitivity to genotoxic stress

    PubMed Central

    Bassi, C; Ho, J; Srikumar, T; Dowling, RJO; Gorrini, C; Miller, SJ; Mak, TW; Neel, BG; Raught, B; Stambolic, V

    2016-01-01

    Loss of function of the Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) tumor suppressor gene is associated with many human cancers. In the cytoplasm, PTEN antagonizes the Phosphatidylinositol 3′ kinase (PI3K) signaling pathway. PTEN also accumulates in the nucleus, where its function remains poorly understood. We demonstrate that SUMOylation (SUMO) of PTEN controls its nuclear localization. In cells exposed to genotoxic stress, SUMO-PTEN was rapidly excluded from the nucleus dependent on the protein kinase Ataxia telangiectasia mutated (ATM). Cells lacking nuclear PTEN were hypersensitive to DNA damage, while PTEN-deficient cells were susceptible to killing by a combination of genotoxic stress and a small molecule PI3K inhibitor both in vitro and in vivo. Our findings may have implications for individualized therapy for patients with PTEN-deficient tumors. PMID:23888040

  10. PTEN regulates AMPA receptor-mediated cell viability in iPS-derived motor neurons.

    PubMed

    Yang, D-J; Wang, X-L; Ismail, A; Ashman, C J; Valori, C F; Wang, G; Gao, S; Higginbottom, A; Ince, P G; Azzouz, M; Xu, J; Shaw, P J; Ning, K

    2014-02-27

    Excitatory transmission in the brain is commonly mediated by the α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors. In amyotrophic lateral sclerosis (ALS), AMPA receptors allow cytotoxic levels of calcium into neurons, contributing to motor neuron injury. We have previously shown that oculomotor neurons resistant to the disease process in ALS show reduced AMPA-mediated inward calcium currents compared with vulnerable spinal motor neurons. We have also shown that PTEN (phosphatase and tensin homolog deleted on chromosome 10) knockdown via siRNA promotes motor neuron survival in models of spinal muscular atrophy (SMA) and ALS. It has been reported that inhibition of PTEN attenuates the death of hippocampal neurons post injury by decreasing the effective translocation of the GluR2 subunit into the membrane. In addition, leptin can regulate AMPA receptor trafficking via PTEN inhibition. Thus, we speculate that manipulation of AMPA receptors by PTEN may represent a potential therapeutic strategy for neuroprotective intervention in ALS and other neurodegenerative disorders. To this end, the first step is to establish a fibroblast-iPS-motor neuron in vitro cell model to study AMPA receptor manipulation. Here we report that iPS-derived motor neurons from human fibroblasts express AMPA receptors. PTEN depletion decreases AMPA receptor expression and AMPA-mediated whole-cell currents, resulting in inhibition of AMPA-induced neuronal death in primary cultured and iPS-derived motor neurons. Taken together, our results imply that PTEN depletion may protect motor neurons by inhibition of excitatory transmission that represents a therapeutic strategy of potential benefit for the amelioration of excitotoxicity in ALS and other neurodegenerative disorders.

  11. Targeting Gastrin-Releasing Peptide Suppresses Neuroblastoma Progression via Upregulation of PTEN Signaling

    PubMed Central

    Paul, Pritha; Qiao, Jingbo; Kim, Kwang Woon; Romain, Carmelle; Lee, Sora; Volny, Natasha; Mobley, Bret; Correa, Hernan; Chung, Dai H.

    2013-01-01

    We have previously demonstrated the role of gastrin-releasing peptide (GRP) as an autocrine growth factor for neuroblastoma. Here, we report that GRP silencing regulates cell signaling involved in the invasion-metastasis cascade. Using a doxycycline inducible system, we demonstrate that GRP silencing decreased anchorage-independent growth, inhibited migration and neuroblastoma cell-mediated angiogenesis in vitro, and suppressed metastasis in vivo. Targeted inhibition of GRP decreased the mRNA levels of oncogenes responsible for neuroblastoma progression. We also identified PTEN/AKT signaling as a key mediator of the tumorigenic properties of GRP in neuroblastoma cells. Interestingly, PTEN overexpression decreased GRP-mediated migration and angiogenesis; a novel role for this, otherwise, understated tumor suppressor in neuroblastoma. Furthermore, activation of AKT (pAKT) positively correlated with neuroblastoma progression in an in vivo tumor-metastasis model. PTEN expression was slightly decreased in metastatic lesions. A similar phenomenon was observed in human neuroblastoma sections, where, early-stage localized tumors had a higher PTEN expression relative to pAKT; however, an inverse expression pattern was observed in liver lesions. Taken together, our results argue for a dual purpose of targeting GRP in neuroblastoma –1) decreasing expression of critical oncogenes involved in tumor progression, and 2) enhancing activation of tumor suppressor genes to treat aggressive, advanced-stage disease. PMID:24039782

  12. Propylthiouracil, independent of its antithyroid effect, promotes vascular smooth muscle cells differentiation via PTEN induction.

    PubMed

    Chen, Wei-Jan; Pang, Jong-Hwei S; Lin, Kwang-Huei; Lee, Dany-Young; Hsu, Lung-An; Kuo, Chi-Tai

    2010-01-01

    Propylthiouracil (PTU), independent of its antithyroid effect, is recently found to have an antiatherosclerotic effect. The aim of this study is to determine the impact of PTU on phenotypic modulation of vascular smooth muscle cells (VSMCs), as phenotypic modulation may contribute to the growth of atherosclerotic lesions and neointimal formation after arterial injury. Propylthiouracil reduced neointimal formation in balloon-injured rat carotid arteries. In vitro, PTU may convert VSMCs from a serum-induced dedifferentiation state to a differentiated state, as indicated by a spindle-shaped morphology and an increase in the expression of SMC differentiation marker contractile proteins, including calponin and smooth muscle (SM)-myosin heavy chain (SM-MHC). Transient transfection studies in VSMCs demonstrated that PTU induced the activity of SMC marker genes (calponin and SM-MHC) promoters, indicating that PTU up-regulates these genes expression predominantly at the transcriptional level. Furthermore, PTU enhanced the expression of PTEN and inhibition of PTEN by siRNA knockdown blocked PTU-induced activation of contractile proteins expression and promoter activity. In the rat carotid injury model, PTU reversed the down-regulation of contractile proteins and up-regulated PTEN in the neointima induced by balloon injury. Propylthiouracil promotes VSMC differentiation, at lest in part, via induction of the PTEN-mediated pathway. These findings suggest a possible mechanism by which PTU may contribute to its beneficial effects on atherogenesis and neointimal formation after arterial injury.

  13. MicroRNA-221 and -222 Regulate Radiation Sensitivity by Targeting the PTEN Pathway

    SciTech Connect

    Zhang Chunzhi; Kang Chunsheng; Wang Ping; Cao Yongzhen; Lv Zhonghong; Yu Shizhu; Wang Guangxiu; Zhang Anling; Jia Zhifan; Han Lei; Yang Chunying; Ishiyama, Hiromichi; Teh, Bin S.; Xu Bo; Pu Peiyu

    2011-05-01

    Purpose: MicroRNAs (miRNAs) are noncoding RNAs inhibiting expression of numerous target genes by posttranscriptional regulation. miRNA-221 and miRNA-222 (miRNA-221/-222) expression is elevated in radioresistant tumor cell lines; however, it is not known whether and how miRNAs control cellular responses to ionizing irradiation. Methods and Materials: We used bioinformatic analyses, luciferase reporter assay, and genetic knockdown and biochemical assays to characterize the regulation pathways of miRNA-221/-222 in response to radiation treatment. Results: We identified the PTEN gene as a target of miRNA-221/-222. Furthermore, we found that knocking down miRNA-221/-222 by antisense oligonucleotides upregulated PTEN expression. Upregulated PTEN expression suppressed AKT activity and increased radiation-induced apoptosis, resulting in enhancement of radiosensitivity in tumor cells. Conclusions: miRNA-221/-222 control radiation sensitivity by regulating the PTEN/AKT pathway and can be explored as novel targets for radiosensitization.

  14. Transposon-induced nuclear mutations that alter chloroplast gene expression

    SciTech Connect

    Barkan, A.

    1992-01-01

    The goal of this project is to use mutant phenotypes as a guide to nuclear genes that determine the timing and localization of chloroplast development The immediate goals are to identify nuclear mutants with defects in chloroplast gene expression from maize lines harboring active Mu transposons; characterize their phenotypes to determine the precise defect in gene expression; clone several of the most interesting mutations by exploiting the transposon tag; and use the clones to further define the roles of these genes in modulating chloroplast gene expression. Three mutants were described earlier that had global defects in chloroplast gene expression. We have found that two of these mutations are allelic. Both alleles have global defects in chloroplast translation initiation, as revealed by the failure to assemble chloroplast mRNAs into polysomes. We have isolated and characterized three new mutants from Mu lines that have novel defects in chloroplast RNA metabolism. We are now ready to begin the task of cloning several of these genes, by using the Mu transposon tag.

  15. Macrophage polarization alters the expression and sulfation pattern of glycosaminoglycans.

    PubMed

    Martinez, Pierre; Denys, Agnès; Delos, Maxime; Sikora, Anne-Sophie; Carpentier, Mathieu; Julien, Sylvain; Pestel, Joël; Allain, Fabrice

    2015-05-01

    Macrophages are major cells of inflammatory process and take part in a large number of physiological and pathological processes. According to tissue environment, they can polarize into pro-inflammatory (M1) or alternative (M2) cells. Although many evidences have hinted to a potential role of cell-surface glycosaminoglycans (GAGs) in the functions of macrophages, the effect of M1 or M2 polarization on the biosynthesis of these polysaccharides has not been investigated so far. GAGs are composed of repeat sulfated disaccharide units. Heparan (HS) and chondroitin/dermatan sulfates (CS/DS) are the major GAGs expressed at the cell membrane. They are involved in numerous biological processes, which rely on their ability to selectively interact with a large panel of proteins. More than 20 genes encoding sulfotransferases have been implicated in HS and CS/DS biosynthesis, and the functional repertoire of HS and CS/DS has been related to the expression of these isoenzymes. In this study, we analyzed the expression of sulfotransferases as a response to macrophage polarization. We found that M1 and M2 activation drastically modified the profiles of expression of numerous HS and CS/DS sulfotransferases. This was accompanied by the expression of GAGs with distinct structural features. We then demonstrated that GAGs of M2 macrophages were efficient to present fibroblast growth factor-2 in an assay of tumor cell proliferation, thus indicating that changes in GAG structure may contribute to the functions of polarized macrophages. Altogether, our findings suggest a regulatory mechanism in which fine modifications in GAG biosynthesis may participate to the plasticity of macrophage functions.

  16. Somatic mutation of PTEN in bladder carcinoma

    PubMed Central

    Aveyard, J S; Skilleter, A; Habuchi, T; Knowles, M A

    1999-01-01

    The tumour suppressor gene PTEN/MMAC1, which is mutated or homozygously deleted in glioma, breast and prostate cancer, is mapped to a region of 10q which shows loss of heterozygosity (LOH) in bladder cancer. We screened 123 bladder tumours for LOH in the region of PTEN. In 53 informative muscle invasive tumours (≥ pT2), allele loss was detected in 13 (24.5%) and allelic imbalance in four tumours (overall frequency 32%). LOH was found in four of 60 (6.6%) informative, non-invasive tumours (pTa/pT1). We screened 63 muscle invasive tumours for PTEN mutations by single-strand conformation polymorphism (SSCP) analysis and for homozygous deletion by duplex quantitative polymerase chain reaction (PCR). Two homozygous deletions were identified but no mutations. Of 15 bladder tumour cell lines analysed, three showed homozygous deletion of all or part of the PTEN gene, but none had mutations detectable by SSCP analysis. Our results indicate that PTEN is involved in the development of some bladder tumours. The low frequency of mutation of the retained allele in tumours with 10q23 LOH suggests that there may be another predominant mechanism of inactivation of the second allele, for example small intragenic deletions, that hemizygosity may be sufficient for phenotypic effect, or that there is another target gene at 10q23. © 1999 Cancer Research Campaign PMID:10360673

  17. PTEN-PDZ domain interactions: binding of PTEN to PDZ domains of PTPN13.

    PubMed

    Sotelo, Natalia S; Schepens, Jan T G; Valiente, Miguel; Hendriks, Wiljan J A J; Pulido, Rafael

    2015-05-01

    Protein modular interactions mediated by PDZ domains are essential for the establishment of functional protein networks controlling diverse cellular functions. The tumor suppressor PTEN possesses a C-terminal PDZ-binding motif (PDZ-BM) that is recognized by a specific set of PDZ domains from scaffolding and regulatory proteins. Here, we review the current knowledge on PTEN-PDZ domain interactions and tumor suppressor networks, describe methodology suitable to analyze these interactions, and report the binding of PTEN and the PDZ domain-containing protein tyrosine phosphatase PTPN13. Yeast two-hybrid and GST pull-down analyses showed that PTEN binds to PDZ2/PTPN13 domain in a manner that depends on the specific PTPN13 PDZ domain arrangement involving the interdomain region between PDZ1 and PDZ2. Furthermore, a specific binding profile of PTEN to PDZ2/PTPN13 domain was observed by mutational analysis of the PTEN PDZ-BM. Our results disclose a PDZ-mediated physical interaction of PTEN and PTPN13 with potential relevance in tumor suppression and cell homeostasis.

  18. Locomotion in Lymphocytes is Altered by Differential PKC Isoform Expression

    NASA Technical Reports Server (NTRS)

    Sundaresan, A.; Risin, D.; Pellis, N. R.

    1999-01-01

    Lymphocyte locomotion is critical for proper elicitation of the immune response. Locomotion of immune cells via the interstitium is essential for optimal immune function during wound healing, inflammation and infection. There are conditions which alter lymphocyte locomotion and one of them is spaceflight. Lymphocyte locomotion is severely inhibited in true spaceflight (true microgravity) and in rotating wall vessel culture (modeled microgravity). When lymphocytes are activated prior to culture in modeled microgravity, locomotion is not inhibited and the levels are comparable to those of static cultured lymphocytes. When a phorbol ester (PMA) is used in modeled microgravity, lymphocyte locomotion is restored by 87%. This occurs regardless if PMA is added after culture in the rotating wall vessel or during culture. Inhibition of DNA synthesis also does not alter restoration of lymphocyte locomotion by PMA. PMA is a direct activator of (protein kinase C) PKC . When a calcium ionophore, ionomycin is used it does not possess any restorative properties towards locomotion either alone or collectively with PMA. Since PMA brings about restoration without help from calcium ionophores (ionomycin), it is infer-red that calcium independent PKC isoforms are involved. Changes were perceived in the protein levels of PKC 6 where levels of the protein were downregulated at 24,72 and 96 hours in untreated rotated cultures (modeled microgravity) compared to untreated static (1g) cultures. At 48 hours there is an increase in the levels of PKC & in the same experimental set up. Studies on transcriptional and translational patterns of calcium independent isoforms of PKC such as 8 and E are presented in this study.

  19. PIK3CA alterations in Middle Eastern ovarian cancers

    PubMed Central

    Abubaker, Jehad; Bavi, Prashant; Al-Haqawi, Wael; Jehan, Zeenath; Munkarah, Adnan; Uddin, Shahab; Al-Kuraya, Khawla S

    2009-01-01

    Background PI3K/AKTsignaling pathway plays an important role in cell growth, proliferation, and tumorgenesis of various malignancies. This signaling pathway has been shown to be frequently altered in several human cancers including ovarian cancers. However the role of this oncogenic signaling pathway has not been explored in the Middle Eastern epithelial ovarian cancer (EOC). Therefore, we investigated PI3K/AKT genetic alterations such as PIK3CA amplification, PIK3CA mutation, PTEN protein loss and their relationships with various clinicopathological characteristics in 156 EOCs. Results Fluorescence in situ hybridization (FISH) technique and DNA sequencing were used to analyze PIK3CA amplification and mutation respectively. Expression of PIK3CA protein expression (p110 α), PTEN, p-AKT and Ki-67 was analyzed by immunohistochemistry. PIK3CA amplification was seen in 54 of 152 (35.5%) EOC cases analyzed; PIK3CA gene mutations in 6/153 EOC (3.9%); KRAS mutations in 3/154 EOC (1.9%), BRAF mutations in 3/156 EOC (1.9%), p53 mutation in 50/154 EOC (32.5%), and loss of PTEN protein expression in 33/144 EOC (22.9%). p110 α overexpression was associated with increased phosphorylation of AKT-Ser 473 and with the proliferation marker Ki-67. Conclusion Our data showed mutual exclusivity between the molecular event of PIK3CA amplification and mutations in PIK3CA, KRAS, BRAF genes, which suggests that each of these alterations may individually be sufficient to drive ovarian tumor pathogenesis independently. High prevalence of genetic alterations in PI3K/AKT pathway in a Middle Eastern ovarian carcinoma provides genetic evidence supporting the notion that dysregulated PI3K/AKT pathways play an important role in the pathogenesis of ovarian cancers. PMID:19638206

  20. Altered circadian clock gene expression in patients with schizophrenia.

    PubMed

    Johansson, Anne-Sofie; Owe-Larsson, Björn; Hetta, Jerker; Lundkvist, Gabriella B

    2016-07-01

    Impaired circadian rhythmicity has been reported in several psychiatric disorders. Schizophrenia is commonly associated with aberrant sleep-wake cycles and insomnia. It is not known if schizophrenia is associated with disturbances in molecular rhythmicity. We cultured fibroblasts from skin samples obtained from patients with chronic schizophrenia and from healthy controls, respectively, and analyzed the circadian expression during 48h of the clock genes CLOCK, BMAL1, PER1, PER2, CRY1, CRY2, REV-ERBα and DBP. In fibroblasts obtained from patients with chronic schizophrenia, we found a loss of rhythmic expression of CRY1 and PER2 compared to cells from healthy controls. We also estimated the sleep quality in these patients and found that most of them suffered from poor sleep in comparison with the healthy controls. In another patient sample, we analyzed mononuclear blood cells from patients with schizophrenia experiencing their first episode of psychosis, and found decreased expression of CLOCK, PER2 and CRY1 compared to blood cells from healthy controls. These novel findings show disturbances in the molecular clock in schizophrenia and have important implications in our understanding of the aberrant rhythms reported in this disease. PMID:27132483

  1. Regulated expression of a calmodulin isoform alters growth and development in potato.

    PubMed

    Poovaiah, B W; Takezawa, D; An, G; Han, T J

    1996-01-01

    A transgene approach was taken to study the consequences of altered expression of a calmodulin isoform on plant growth and development. Eight genomic clones of potato calmodulin (PCM1 to 8) have been isolated and characterized (Takezawa et al., 1995). Among the potato calmodulin isoforms studied, PCM1 differs from the other isoforms because of its unique amino acid substitutions. Transgenic potato plants were produced carrying sense construct of PCM1 fused to the CaMV 35S promoter. Transgenic plants showing a moderate increase in PCM1 mRNA exhibited strong apical dominance, produced elongated tubers, and were taller than the controls. Interestingly, the plants expressing the highest level of PCM1 mRNA did not form underground tubers. Instead, these transgenic plants produced aerial tubers when allowed to grow for longer periods. The expression of different calmodulin isoforms (PCM1, 5, 6, and 8) was studied in transgenic plants. Among the four potato calmodulin isoforms, only the expression of PCM1 mRNA was altered in transgenic plants, while the expression of other isoforms was not significantly altered. Western analysis revealed increased PCM1 protein in transgenic plants, indicating that the expression of both mRNA and protein are altered in transgenic plants. These results suggest that increasing the expression of PCM1 alters growth and development in potato plants.

  2. Regulated Expression of a Calmodulin Isoform Alters Growth and Development in Potato

    NASA Technical Reports Server (NTRS)

    Poovaiah, B. W.; Takezawa, D.; An, G.; Han, T.-J.

    1996-01-01

    A transgene approach was taken to study the consequences of altered expression of a calmodutin iso-form on plant growth and development. Eight genomic clones of potato calmodulin (PCM 1 to 8) have been isolated and characterized. Among the potato calmodulin isoforms studied, PCM 1 differs from the other isoforms because of its unique amino acid substitutions. Transgenic potato plants were produced carrying sense construct of PCM 1 fused to the CAMV 35S promoter. Transgenic plants showing a moderate increase in PCM 1 MRNA exhibited strong apical dominance, produced elongated tubers, and were taller than the controls. Interestingly, the plants expressing the highest level of PCM 1 MRNA did not form underground tubers. Instead, these transgenic plants produced aerial tubers when allowed to grow for longer periods. The expression of different calmodulin isoforms (PCM 1, 5, 6, and 8) was studied in transgenic plants. Among the four potato calmodulin isoforms, only the expression of PCM 1 MRNA was altered in transgenic plants, while the expression of other isoforms was not significantly altered. Western analysis revealed increased PCM 1 protein in transgenic plants, indicating that the expression of both MRNA and protein are altered in transgenic plants. These results suggest that increasing the expression of PCM 1 alters growth and development in potato plants.

  3. Genomic expression of mesenchymal stem cells to altered nanoscale topographies.

    PubMed

    Dalby, Matthew J; Andar, Abhay; Nag, Abhijit; Affrossman, Stanley; Tare, Rahul; McFarlane, Sara; Oreffo, Richard O C

    2008-09-01

    The understanding of cellular response to the shape of their environment would be of benefit in the development of artificial extracellular environments for potential use in the production of biomimetic surfaces. Specifically, the understanding of how cues from the extracellular environment can be used to understand stem cell differentiation would be of special interest in regenerative medicine. In this paper, the genetic profile of mesenchymal stem cells cultured on two osteogenic nanoscale topographies (pitted surface versus raised islands) are compared with cells treated with dexamethasone, a corticosteroid routinely used to stimulate bone formation in culture from mesenchymal stem cells, using 19k gene microarrays as well as 101 gene arrays specific for osteoblast and endothelial biology. The current studies show that by altering the shape of the matrix a cell response (genomic profile) similar to that achieved with chemical stimulation can be elicited. Here, we show that bone formation can be achieved with efficiency similar to that of dexamethasone with the added benefit that endothelial cell development is not inhibited. We further show that the mechanism of action of the topographies and dexamethasone differs. This could have an implication for tissue engineering in which a simultaneous, targeted, development of a tissue, such as bone, without the suppression of angiogenesis to supply nutrients to the new tissue is required. The results further demonstrate that perhaps the shape of the extracellular matrix is critical to tissue development. PMID:18270147

  4. Neurotoxocarosis alters myelin protein gene transcription and expression.

    PubMed

    Heuer, Lea; Beyerbach, Martin; Lühder, Fred; Beineke, Andreas; Strube, Christina

    2015-06-01

    Neurotoxocarosis is an infection of the central nervous system caused by migrating larvae of the common dog and cat roundworms (Toxocara canis and Toxocara cati), which are zoonotic agents. As these parasites are prevalent worldwide and neuropathological and molecular investigations on neurotoxocarosis are scare, this study aims to characterise nerve fibre demyelination associated with neurotoxocarosis on a molecular level. Transcription of eight myelin-associated genes (Cnp, Mag, Mbp, Mog, Mrf-1, Nogo-A, Plp1, Olig2) was determined in the mouse model during six time points of the chronic phase of infection using qRT-PCR. Expression of selected proteins was analysed by Western blotting or immunohistochemistry. Additionally, demyelination and neuronal damage were investigated histologically. Significant differences (p ≤ 0.05) between transcription rates of T. canis-infected and uninfected control mice were detected for all analysed genes while T. cati affected five of eight investigated genes. Interestingly, 2', 3 ´-cyclic nucleotide 3'-phosphodiesterase (Cnp) and myelin oligodendrocyte glycoprotein (Mog) were upregulated in both T. canis- and T. cati-infected mice preceding demyelination. Later, CNPase expression was additionally enhanced. As expected, myelin basic protein (Mbp) was downregulated in cerebra and cerebella of T. canis-infected mice when severe demyelination was present 120 days post infectionem (dpi). The transcriptional pattern observed in the present study appears to reflect direct traumatic and hypoxic effects of larval migration as well as secondary processes including host immune reactions, demyelination and attempts to remyelinate damaged areas.

  5. Identification of reference genes in human myelomonocytic cells for gene expression studies in altered gravity.

    PubMed

    Thiel, Cora S; Hauschild, Swantje; Tauber, Svantje; Paulsen, Katrin; Raig, Christiane; Raem, Arnold; Biskup, Josefine; Gutewort, Annett; Hürlimann, Eva; Unverdorben, Felix; Buttron, Isabell; Lauber, Beatrice; Philpot, Claudia; Lier, Hartwin; Engelmann, Frank; Layer, Liliana E; Ullrich, Oliver

    2015-01-01

    Gene expression studies are indispensable for investigation and elucidation of molecular mechanisms. For the process of normalization, reference genes ("housekeeping genes") are essential to verify gene expression analysis. Thus, it is assumed that these reference genes demonstrate similar expression levels over all experimental conditions. However, common recommendations about reference genes were established during 1 g conditions and therefore their applicability in studies with altered gravity has not been demonstrated yet. The microarray technology is frequently used to generate expression profiles under defined conditions and to determine the relative difference in expression levels between two or more different states. In our study, we searched for potential reference genes with stable expression during different gravitational conditions (microgravity, normogravity, and hypergravity) which are additionally not altered in different hardware systems. We were able to identify eight genes (ALB, B4GALT6, GAPDH, HMBS, YWHAZ, ABCA5, ABCA9, and ABCC1) which demonstrated no altered gene expression levels in all tested conditions and therefore represent good candidates for the standardization of gene expression studies in altered gravity. PMID:25654098

  6. Identification of reference genes in human myelomonocytic cells for gene expression studies in altered gravity.

    PubMed

    Thiel, Cora S; Hauschild, Swantje; Tauber, Svantje; Paulsen, Katrin; Raig, Christiane; Raem, Arnold; Biskup, Josefine; Gutewort, Annett; Hürlimann, Eva; Unverdorben, Felix; Buttron, Isabell; Lauber, Beatrice; Philpot, Claudia; Lier, Hartwin; Engelmann, Frank; Layer, Liliana E; Ullrich, Oliver

    2015-01-01

    Gene expression studies are indispensable for investigation and elucidation of molecular mechanisms. For the process of normalization, reference genes ("housekeeping genes") are essential to verify gene expression analysis. Thus, it is assumed that these reference genes demonstrate similar expression levels over all experimental conditions. However, common recommendations about reference genes were established during 1 g conditions and therefore their applicability in studies with altered gravity has not been demonstrated yet. The microarray technology is frequently used to generate expression profiles under defined conditions and to determine the relative difference in expression levels between two or more different states. In our study, we searched for potential reference genes with stable expression during different gravitational conditions (microgravity, normogravity, and hypergravity) which are additionally not altered in different hardware systems. We were able to identify eight genes (ALB, B4GALT6, GAPDH, HMBS, YWHAZ, ABCA5, ABCA9, and ABCC1) which demonstrated no altered gene expression levels in all tested conditions and therefore represent good candidates for the standardization of gene expression studies in altered gravity.

  7. Identification of Reference Genes in Human Myelomonocytic Cells for Gene Expression Studies in Altered Gravity

    PubMed Central

    Thiel, Cora S.; Hauschild, Swantje; Tauber, Svantje; Paulsen, Katrin; Raig, Christiane; Raem, Arnold; Biskup, Josefine; Gutewort, Annett; Hürlimann, Eva; Philpot, Claudia; Lier, Hartwin; Engelmann, Frank; Layer, Liliana E.

    2015-01-01

    Gene expression studies are indispensable for investigation and elucidation of molecular mechanisms. For the process of normalization, reference genes (“housekeeping genes”) are essential to verify gene expression analysis. Thus, it is assumed that these reference genes demonstrate similar expression levels over all experimental conditions. However, common recommendations about reference genes were established during 1 g conditions and therefore their applicability in studies with altered gravity has not been demonstrated yet. The microarray technology is frequently used to generate expression profiles under defined conditions and to determine the relative difference in expression levels between two or more different states. In our study, we searched for potential reference genes with stable expression during different gravitational conditions (microgravity, normogravity, and hypergravity) which are additionally not altered in different hardware systems. We were able to identify eight genes (ALB, B4GALT6, GAPDH, HMBS, YWHAZ, ABCA5, ABCA9, and ABCC1) which demonstrated no altered gene expression levels in all tested conditions and therefore represent good candidates for the standardization of gene expression studies in altered gravity. PMID:25654098

  8. Nursing frequency alters circadian patterns of mammary gene expression in lactating mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Milking frequency impacts lactation in dairy cattle and in rodent models of lactation. The role of circadian gene expression in this process is unknown. The hypothesis tested was that changing nursing frequency alters the circadian patterns of mammary gene expression. Mid-lactation CD1 mice were stu...

  9. Fine-Tuning of PI3K/AKT Signalling by the Tumour Suppressor PTEN Is Required for Maintenance of Flight Muscle Function and Mitochondrial Integrity in Ageing Adult Drosophila melanogaster

    PubMed Central

    Mensah, Lawrence B.; Davison, Claire; Fan, Shih-Jung; Morris, John F.; Goberdhan, Deborah C. I.; Wilson, Clive

    2015-01-01

    Insulin/insulin-like growth factor signalling (IIS), acting primarily through the PI3-kinase (PI3K)/AKT kinase signalling cassette, plays key evolutionarily conserved regulatory roles in nutrient homeostasis, growth, ageing and longevity. The dysfunction of this pathway has been linked to several age-related human diseases including cancer, Type 2 diabetes and neurodegenerative disorders. However, it remains unclear whether minor defects in IIS can independently induce the age-dependent functional decline in cells that accompany some of these diseases or whether IIS alters the sensitivity to other aberrant signalling. We identified a novel hypomorphic allele of PI3K’s direct antagonist, Phosphatase and tensin homologue on chromosome 10 (Pten), in the fruit fly, Drosophila melanogaster. Adults carrying combinations of this allele, Pten5, combined with strong loss-of-function Pten mutations exhibit subtle or no increase in mass, but are highly susceptible to a wide range of stresses. They also exhibit dramatic upregulation of the oxidative stress response gene, GstD1, and a progressive loss of motor function that ultimately leads to defects in climbing and flight ability. The latter phenotype is associated with mitochondrial disruption in indirect flight muscles, although overall muscle structure appears to be maintained. We show that the phenotype is partially rescued by muscle-specific expression of the Bcl-2 homologue Buffy, which in flies, maintains mitochondrial integrity, modulates energy homeostasis and suppresses cell death. The flightless phenotype is also suppressed by mutations in downstream IIS signalling components, including those in the mechanistic Target of Rapamycin Complex 1 (mTORC1) pathway, suggesting that elevated IIS is responsible for functional decline in flight muscle. Our data demonstrate that IIS levels must be precisely regulated by Pten in adults to maintain the function of the highly metabolically active indirect flight muscles

  10. Neurotoxocarosis alters myelin protein gene transcription and expression.

    PubMed

    Heuer, Lea; Beyerbach, Martin; Lühder, Fred; Beineke, Andreas; Strube, Christina

    2015-06-01

    Neurotoxocarosis is an infection of the central nervous system caused by migrating larvae of the common dog and cat roundworms (Toxocara canis and Toxocara cati), which are zoonotic agents. As these parasites are prevalent worldwide and neuropathological and molecular investigations on neurotoxocarosis are scare, this study aims to characterise nerve fibre demyelination associated with neurotoxocarosis on a molecular level. Transcription of eight myelin-associated genes (Cnp, Mag, Mbp, Mog, Mrf-1, Nogo-A, Plp1, Olig2) was determined in the mouse model during six time points of the chronic phase of infection using qRT-PCR. Expression of selected proteins was analysed by Western blotting or immunohistochemistry. Additionally, demyelination and neuronal damage were investigated histologically. Significant differences (p ≤ 0.05) between transcription rates of T. canis-infected and uninfected control mice were detected for all analysed genes while T. cati affected five of eight investigated genes. Interestingly, 2', 3 ´-cyclic nucleotide 3'-phosphodiesterase (Cnp) and myelin oligodendrocyte glycoprotein (Mog) were upregulated in both T. canis- and T. cati-infected mice preceding demyelination. Later, CNPase expression was additionally enhanced. As expected, myelin basic protein (Mbp) was downregulated in cerebra and cerebella of T. canis-infected mice when severe demyelination was present 120 days post infectionem (dpi). The transcriptional pattern observed in the present study appears to reflect direct traumatic and hypoxic effects of larval migration as well as secondary processes including host immune reactions, demyelination and attempts to remyelinate damaged areas. PMID:25773181

  11. PTEN inhibits macrophage polarization from M1 to M2 through CCL2 and VEGF-A reduction and NHERF-1 synergism.

    PubMed

    Li, Ning; Qin, Junfang; Lan, Lan; Zhang, Hongyao; Liu, Fang; Wu, Zhaozhen; Ni, Hong; Wang, Yue

    2015-01-01

    PTEN has been studied in several tumor models as a tumor suppressor. In this study, we explored the role of PTEN in the inhibition state of polarized M2 subtype of macrophage in tumor microenvironment (TME) and the underlying mechanisms. To elucidate the potential effect in TME, RAW 264.7 macrophages and 4T1 mouse breast cancer cells were co-cultured to reconstruct tumor microenvironment. After PTEN was down-regulated with shRNA, the expression of CCL2 and VEGF-A, which are definited to promote the formation of M2 macrophages, have a dramatically increase on the level of both gene and protein in co-cultured RAW 264.7 macrophages. And at the same time, NHERF-1 (Na(+)/H(+) exchanger regulating factor-1), another tumor suppressor has a similar tendency to PTEN. Q-PCR and WB results suggested that PTEN and NHERF-1 were consistent with one another no matter at mRNA or protein level when exposed to the same stimulus. Coimmunoprecipitation and immunofluorescence techniques confirmed that PTEN and NHERF-1 were coprecipitated, and NHERF-1 protein expression was properly reduced with rCCL2 effect. In addition, cell immunofluorescence images revealed a profound transferance, in co-cultured RAW 264.7 macrophages, an up-regulation of NHERF-1 could promote the PTEN marked expression on the cell membrane, and this form for the interaction was not negligible. These observations illustrate PTEN with a certain synergy of NHERF-1, as well as down-regulation of CCL2 suppressing M2 macrophage transformation pathway. The results suggest that the activation of PTEN and NHERF-1 may impede the evolution of macrophages beyond the M1 into M2 phenotype in tumor microenvironment.

  12. Nuclear PTEN tumor-suppressor functions through maintaining heterochromatin structure.

    PubMed

    Gong, Lili; Govan, Jeane M; Evans, Elizabeth B; Dai, Hui; Wang, Edward; Lee, Szu-Wei; Lin, Hui-Kuan; Lazar, Alexander J; Mills, Gordon B; Lin, Shiaw-Yih

    2015-01-01

    The tumor suppressor, PTEN, is one of the most commonly mutated genes in cancer. Recently, PTEN has been shown to localize in the nucleus and is required to maintain genomic stability. Here, we show that nuclear PTEN, independent of its phosphatase activity, is essential for maintaining heterochromatin structure. Depletion of PTEN leads to loss of heterochromatic foci, decreased chromatin compaction, overexpression of heterochromatic genes, and reduced protein stability of heterochromatin protein 1 α. We found that the C-terminus of PTEN is required to maintain heterochromatin structure. Additionally, cancer-associated PTEN mutants lost their tumor-suppressor function when their heterochromatin structure was compromised. We propose that this novel role of PTEN accounts for its function in guarding genomic stability and suppressing tumor development. PMID:25946202

  13. Nuclear PTEN tumor-suppressor functions through maintaining heterochromatin structure

    PubMed Central

    Gong, Lili; Govan, Jeane M; Evans, Elizabeth B; Dai, Hui; Wang, Edward; Lee, Szu-Wei; Lin, Hui-Kuan; Lazar, Alexander J; Mills, Gordon B; Lin, Shiaw-Yih

    2015-01-01

    The tumor suppressor, PTEN, is one of the most commonly mutated genes in cancer. Recently, PTEN has been shown to localize in the nucleus and is required to maintain genomic stability. Here, we show that nuclear PTEN, independent of its phosphatase activity, is essential for maintaining heterochromatin structure. Depletion of PTEN leads to loss of heterochromatic foci, decreased chromatin compaction, overexpression of heterochromatic genes, and reduced protein stability of heterochromatin protein 1 α. We found that the C-terminus of PTEN is required to maintain heterochromatin structure. Additionally, cancer-associated PTEN mutants lost their tumor-suppressor function when their heterochromatin structure was compromised. We propose that this novel role of PTEN accounts for its function in guarding genomic stability and suppressing tumor development. PMID:25946202

  14. PTEN Mediates the Antioxidant Effect of Resveratrol at Nutritionally Relevant Concentrations

    PubMed Central

    Inglés, Marta; Gambini, Juan; Miguel, M. Graça; Bonet-Costa, Vicent; Abdelaziz, Kheira M.; El Alami, Marya; Viña, Jose; Borrás, Consuelo

    2014-01-01

    Introduction. Antioxidant properties of resveratrol have been intensively studied for the last years, both in vivo and in vitro. Its bioavailability after an oral dose is very low and therefore it is very important to make sure that plasma concentrations of free resveratrol are sufficient enough to be active as antioxidant. Aims. In the present study, using nutritionally relevant concentrations of resveratrol, we aim to confirm its antioxidant capacity on reducing peroxide levels and look for the molecular pathway involved in this antioxidant effect. Methods. We used mammary gland tumor cells (MCF-7), which were pretreated with different concentrations of resveratrol for 48 h, and/or a PTEN inhibitor (bpV: bipy). Hydrogen peroxide levels were determined by fluorimetry, PTEN levels and Akt phosphorylation by Western Blotting, and mRNA expression of antioxidant genes by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Results. Resveratrol treatment for 48 h lowered peroxide levels in MCF-7, even at low nutritional concentrations (1 nM). This effect was mediated by the activation of PTEN/Akt pathway, which resulted in an upregulation of catalase and MnSOD mRNA levels. Conclusion. Resveratrol acts as an antioxidant at nutritionally relevant concentrations by inducing the expression of antioxidant enzymes, through a mechanism involving PTEN/Akt signaling pathway. PMID:24812624

  15. MAF1 suppresses AKT‐mTOR signaling and liver cancer through activation of PTEN transcription

    PubMed Central

    Li, Yue; Tsang, Chi Kwan; Wang, Suihai; Li, Xiao‐Xing; Yang, Yang; Fu, Liwu; Huang, Wenlin; Li, Ming

    2016-01-01

    The phosphatidylinositol 3‐kinase/phosphatidylinositol 3,4,5‐trisphosphate 3‐phosphatase/protein kinase B/mammalian target of rapamycin (PI3K‐PTEN‐AKT‐mTOR) pathway is a central controller of cell growth and a key driver for human cancer. MAF1 is an mTOR downstream effector and transcriptional repressor of ribosomal and transfer RNA genes. MAF1 expression is markedly reduced in hepatocellular carcinomas, which is correlated with disease progression and poor prognosis. Consistently, MAF1 displays tumor‐suppressor activity toward in vitro and in vivo cancer models. Surprisingly, blocking the synthesis of ribosomal and transfer RNAs is insufficient to account for MAF1's tumor‐suppressor function. Instead, MAF1 down‐regulation paradoxically leads to activation of AKT‐mTOR signaling, which is mediated by decreased PTEN expression. MAF1 binds to the PTEN promoter, enhancing PTEN promoter acetylation and activity. Conclusion: In contrast to its canonical function as a transcriptional repressor, MAF1 can also act as a transcriptional activator for PTEN, which is important for MAF1's tumor‐suppressor function. These results have implications in disease staging, prognostic prediction, and AKT‐mTOR‐targeted therapy in liver cancer. (Hepatology 2016;63:1928‐1942) PMID:26910647

  16. Hypoxia alters MicroRNA expression in rat cortical pericytes.

    PubMed

    Truettner, Jessie S; Katyshev, Vladimir; Esen-Bilgin, Nilufer; Dietrich, W Dalton; Dore-Duffy, Paula

    2013-01-01

    Microvascular adaptation to metabolic stress is important in the maintenance of tissue homeostasis. Nowhere is this more important than in the central nervous system (CNS) where the cellular constituents of the neurovascularture including endothelial cells, pericytes and some astroglia must make fine-tuned autoregulatory modulations that maintain the delicate balance between oxygen availability and metabolic demand. miRNAs have been reported to play an important regulatory role in many cellular functions including cell differentiation, growth and proliferation, lineage determination, and metabolism. In this study, we investigated the possible role of miRNAs in the CNS capillary pericyte response to hypoxic stress. Micro-array analysis was used to examine the expression of 388 rat miRNAs in primary rat cortical pericytes with and without exposure to low oxygen (1%) after 24 or 48 hr. Pericytes subjected to hypoxia showed 27 miRNAs that were higher than control and 31 that were lower. Validation and quantification was performed by Real Time RT-PCR on pericytes subjected to 2 hr, 24 hr, or 48 hr of hypoxia. Hypoxia induced changes included physiological pathways governing the stress response, angiogenesis, migration and cell cycle regulation. miRNAs associated with HIF-1α (miR-322[1], miR-199a [2]), TGF-β1 (miR-140[3], miR-145[4], miR-376b-3p[5]) and VEGF (miR-126a[6], miR-297[7], miR-16[8], miR-17-5p[9]) were differentially regulated. Systematic and integrative analysis of possible gene targets analyzed by DAVID bioinformatics resource (http://david.abcc.ncifcrf.gov) and MetaSearch 2.0 (GeneGo) for some of these miRNAs was conducted to determine possible gene targets and pathways that may be affected by the post-transcriptional changes after hypoxic insult.

  17. Pten (phosphatase and tensin homologue gene) haploinsufficiency promotes insulin hypersensitivity

    PubMed Central

    Wong, J. T.; Kim, P. T. W.; Peacock, J. W.; Yau, T. Y.; Mui, A. L.-F.; Chung, S. W.; Sossi, V.; Doudet, D.; Green, D.; Ruth, T. J.; Parsons, R.; Verchere, C. B.

    2006-01-01

    Aims/hypothesis Insulin controls glucose metabolism via multiple signalling pathways, including the phosphatidylinositol 3-kinase (PI3K) pathway in muscle and adipose tissue. The protein/lipid phosphatase Pten (phosphatase and tensin homologue deleted on chromosome 10) attenuates PI3K signalling by dephosphorylating the phosphatidylinositol 3,4,5-trisphosphate generated by PI3K. The current study was aimed at investigating the effect of haploinsufficiency for Pten on insulin-stimulated glucose uptake. Materials and methods Insulin sensitivity in Pten heterozygous (Pten+/−) mice was investigated in i.p. insulin challenge and glucose tolerance tests. Glucose uptake was monitored in vitro in primary cultures of myocytes from Pten+/− mice, and in vivo by positron emission tomography. The phosphorylation status of protein kinase B (PKB/Akt), a downstream signalling protein in the PI3K pathway, and glycogen synthase kinase 3β (GSK3β), a substrate of PKB/Akt, was determined by western immunoblotting. Results Following i.p. insulin challenge, blood glucose levels in Pten+/− mice remained depressed for up to 120 min, whereas glucose levels in wild-type mice began to recover after approximately 30 min. After glucose challenge, blood glucose returned to normal about twice as rapidly in Pten+/− mice. Enhanced glucose uptake was observed both in Pten+/− myocytes and in skeletal muscle of Pten+/− mice by PET. PKB and GSK3β phosphorylation was enhanced and prolonged in Pten+/− myocytes. Conclusions/interpretation Pten is a key negative regulator of insulin-stimulated glucose uptake in vitro and in vivo. The partial reduction of Pten due to Pten haploinsufficiency is enough to elicit enhanced insulin sensitivity and glucose tolerance in Pten+/− mice. PMID:17195063

  18. Altered Expression of Diabetes-Related Genes in Alzheimer's Disease Brains: The Hisayama Study

    PubMed Central

    Hokama, Masaaki; Oka, Sugako; Leon, Julio; Ninomiya, Toshiharu; Honda, Hiroyuki; Sasaki, Kensuke; Iwaki, Toru; Ohara, Tomoyuki; Sasaki, Tomio; LaFerla, Frank M.; Kiyohara, Yutaka; Nakabeppu, Yusaku

    2014-01-01

    Diabetes mellitus (DM) is considered to be a risk factor for dementia including Alzheimer's disease (AD). However, the molecular mechanism underlying this risk is not well understood. We examined gene expression profiles in postmortem human brains donated for the Hisayama study. Three-way analysis of variance of microarray data from frontal cortex, temporal cortex, and hippocampus was performed with the presence/absence of AD and vascular dementia, and sex, as factors. Comparative analyses of expression changes in the brains of AD patients and a mouse model of AD were also performed. Relevant changes in gene expression identified by microarray analysis were validated by quantitative real-time reverse-transcription polymerase chain reaction and western blotting. The hippocampi of AD brains showed the most significant alteration in gene expression profile. Genes involved in noninsulin-dependent DM and obesity were significantly altered in both AD brains and the AD mouse model, as were genes related to psychiatric disorders and AD. The alterations in the expression profiles of DM-related genes in AD brains were independent of peripheral DM-related abnormalities. These results indicate that altered expression of genes related to DM in AD brains is a result of AD pathology, which may thereby be exacerbated by peripheral insulin resistance or DM. PMID:23595620

  19. Physical Foundations of PTEN/Phosphoinositide Interaction

    NASA Astrophysics Data System (ADS)

    Gericke, Arne; Jiang, Zhiping; Redfern, Roberta E.; Kooijman, Edgar E.; Ross, Alonzo H.

    2009-03-01

    Phosphoinositides act as signaling molecules by recruiting critical effectors to specific subcellular membranes to regulate cell proliferation, apoptosis and cytoskeletal reorganization, which requires a tight regulation of phosphoinositide generation and turnover as well as a high degree of compartmentalization. PTEN is a phosphatase specific for the 3 position of the phosophoinositide ring that is deleted or mutated in many different disease states. PTEN association with membranes requires the interaction of its C2 domain with phosphatidylserine and the interaction of its N-terminal end with phosphatidylinositol-4,5-bisphophate (PI(4,5)P2). We have investigated PTEN/PI(4,5)P2 interaction and found that Lys13 is crucial for the observed binding. We also found that the presence of cholesterol enhances PTEN binding to mixed PI(4,5)P2/POPC vesicles. Fluorescence microscopy experiments utilizing GUVs yielded results consistent with enhanced phosphoinositide domain formation in the presence of cholesterol. These experiments were accompanied by zeta potential measurements and solid state MAS ^31P-NMR experiments aimed at investigating the ionization behavior of phosphoinositides.

  20. Computational identification of altered metabolism using gene expression and metabolic pathways.

    PubMed

    Nam, Hojung; Lee, Jinwon; Lee, Doheon

    2009-07-01

    Understanding altered metabolism is an important issue because altered metabolism is often revealed as a cause or an effect in pathogenesis. It has also been shown to be an important factor in the manipulation of an organism's metabolism in metabolic engineering. Unfortunately, it is not yet possible to measure the concentration levels of all metabolites in the genome-wide scale of a metabolic network; consequently, a method that infers the alteration of metabolism is beneficial. The present study proposes a computational method that identifies genome-wide altered metabolism by analyzing functional units of KEGG pathways. As control of a metabolic pathway is accomplished by altering the activity of at least one rate-determining step enzyme, not all gene expressions of enzymes in the pathway demonstrate significant changes even if the pathway is altered. Therefore, we measure the alteration levels of a metabolic pathway by selectively observing expression levels of significantly changed genes in a pathway. The proposed method was applied to two strains of Saccharomyces cerevisiae gene expression profiles measured in very high-gravity (VHG) fermentation. The method identified altered metabolic pathways whose properties are related to ethanol and osmotic stress responses which had been known to be observed in VHG fermentation because of the high sugar concentration in growth media and high ethanol concentration in fermentation products. With the identified altered pathways, the proposed method achieved best accuracy and sensitivity rates for the Red Star (RS) strain compared to other three related studies (gene-set enrichment analysis (GSEA), significance analysis of microarray to gene set (SAM-GS), reporter metabolite), and for the CEN.PK 113-7D (CEN) strain, the proposed method and the GSEA method showed comparably similar performances.

  1. Antipsychotic pathway genes with expression altered in opposite direction by antipsychotics and amphetamine.

    PubMed

    Ko, Françoise; Tallerico, Teresa; Seeman, Philip

    2006-08-01

    To develop a new strategy for identifying possible psychotic- or antipsychotic-related pathway genes, rats were treated with clinical doses of haloperidol and clozapine for 4 days, and the altered expression of genes was compared with the genes altered in expression after amphetamine sensitization. The objective was to identify genes with expression altered in the same direction by haloperidol and clozapine but in the opposite direction in the amphetamine-sensitized rat striatum. These criteria were met by 21 genes, consisting of 15 genes upregulated by amphetamine, and 6 genes downregulated by amphetamine. Of the 21 genes, 15 are not presently identified, and only 3 genes (cathepsin K, GRK6, and a gene with accession number AI177589) are located in chromosome regions known to be associated with schizophrenia.

  2. Adenovirus-mediated ING4/PTEN double tumor suppressor gene co-transfer modified by RGD enhances antitumor activity in human nasopharyngeal carcinoma cells.

    PubMed

    Wang, Yihong; Yang, Jicheng; Sheng, Weihua; Xie, Yufeng; Liu, Jisheng

    2015-03-01

    Inhibitor of growth-4 (ING4) is a member of the inhibitor of growth (ING) family and acts as a tumor suppressor protein. PTEN is a phosphatase and shows potent and extensive antitumor activity. In this study, we constructed an RGD-modified bicistronic ING4/PTEN adenovirus (Ad.RGD-ING4-PTEN) and comprehensively investigated its effects following modification of the CNE human nasopharyngeal carcinoma cell line both in vitro and in vivo. We demonstrated that Ad.RGD-ING4-PTEN enhanced growth inhibition and apoptosis. Furthermore, expression of P21, Bax and cleaved caspase-3 was upregulated, while that of Bcl-2 and survivin was downregulated in CNE cells and CNE xenografted tumors. Moreover, Ad.RGD-ING4-PTEN treatment additively downregulated CD34, VEGF and microvessel density in subcutaneously (s.c.) xenografted CNE cell tumors. The enhanced antitumor activity generated by Ad.RGD-ING4-PTEN was closely associated with activation of the intrinsic and extrinsic apoptotic pathways and additive inhibition of tumor angiogenesis both in vitro and in vivo. On the basis of this evidence, it is believed that cancer gene therapy combining two tumor suppressors such as ING4 and PTEN can be used to establish an effective and novel therapeutic strategy for nasopharyngeal carcinoma and other cancers.

  3. Simultaneous inactivation of Par-4 and PTEN in vivo leads to synergistic NF-κB activation and invasive prostate carcinoma

    PubMed Central

    Fernandez-Marcos, Pablo J.; Abu-Baker, Shadi; Joshi, Jayashree; Galvez, Anita; Castilla, Elias A.; Cañamero, Marta; Collado, Manuel; Saez, Carmen; Moreno-Bueno, Gema; Palacios, Jose; Leitges, Michael; Serrano, Manuel; Moscat, Jorge; Diaz-Meco, Maria T.

    2009-01-01

    Prostate cancer is one of the most common neoplasias in men. The tumor suppressor Par-4 is an important negative regulator of the canonical NF-κB pathway and is highly expressed in prostate. Here we show that Par-4 expression is lost in a high percentage of human prostate carcinomas, and this occurs in association with phosphatase and tensin homolog deleted from chromosome 10 (PTEN) loss. Par-4 null mice, similar to PTEN-heterozygous mice, only develop benign prostate lesions, but, importantly, concomitant Par-4 ablation and PTEN-heterozygosity lead to invasive prostate carcinoma in mice. This strong tumorigenic cooperation is anticipated in the preneoplastic prostate epithelium by an additive increase in Akt activation and a synergistic stimulation of NF-κB. These results establish the cooperation between Par-4 and PTEN as relevant for the development of prostate cancer and implicate the NF-κB pathway as a critical event in prostate tumorigenesis. PMID:19470463

  4. 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.

  5. The polycomb group protein Bmi-1 represses the tumor suppressor PTEN and induces epithelial-mesenchymal transition in human nasopharyngeal epithelial cells

    PubMed Central

    Song, Li-Bing; Li, Jun; Liao, Wen-Ting; Feng, Yan; Yu, Chun-Ping; Hu, Li-Juan; Kong, Qing-Li; Xu, Li-Hua; Zhang, Xing; Liu, Wan-Li; Li, Man-Zhi; Zhang, Ling; Kang, Tie-Bang; Fu, Li-Wu; Huang, Wen-Lin; Xia, Yun-Fei; Tsao, Sai Wah; Li, Mengfeng; Band, Vimla; Band, Hamid; Shi, Qing-Hua; Zeng, Yi-Xin; Zeng, Mu-Sheng

    2009-01-01

    The polycomb group protein B lymphoma Mo-MLV insertion region 1 homolog (Bmi-1) is dysregulated in various cancers, and its upregulation strongly correlates with an invasive phenotype and poor prognosis in patients with nasopharyngeal carcinomas. However, the underlying mechanism of Bmi-1–mediated invasiveness remains unknown. In the current study, we found that upregulation of Bmi-1 induced epithelial-mesenchymal transition (EMT) and enhanced the motility and invasiveness of human nasopharyngeal epithelial cells, whereas silencing endogenous Bmi-1 expression reversed EMT and reduced motility. Furthermore, upregulation of Bmi-1 led to the stabilization of Snail, a transcriptional repressor associated with EMT, via modulation of PI3K/Akt/GSK-3β signaling. Chromatin immunoprecipitation assays revealed that Bmi-1 transcriptionally downregulated expression of the tumor suppressor PTEN in tumor cells through direct association with the PTEN locus. This in vitro analysis was consistent with the statistical inverse correlation detected between Bmi-1 and PTEN expression in a cohort of human nasopharyngeal carcinoma biopsies. Moreover, ablation of PTEN expression partially rescued the migratory/invasive phenotype of Bmi-1–silenced cells, indicating that PTEN might be a major mediator of Bmi-1–induced EMT. Our results provide functional and mechanistic links between the oncoprotein Bmi-1 and the tumor suppressor PTEN in the development and progression of cancer. PMID:19884659

  6. Adipocyte gene expression is altered in formerly obese mice and as a function of diet composition.

    PubMed

    Miller, Ryan S; Becker, Kevin G; Prabhu, Vinayakumar; Cooke, David W

    2008-06-01

    In the development of obesity, the source of excess energy may influence appetite and metabolism. To determine the effects of differences in diet composition in obesity, mice were fed either a high-carbohydrate diet (HC; 10% fat energy) or a high-fat energy-restricted diet (HFR; 60% fat energy) over 18 wk in weight-matched groups of mice. To identify obesity-associated genes with persistently altered expression following weight reduction, mice were fed either a standard low-fat diet (LF; 10% fat energy), an unrestricted high-fat diet (HF; 60% fat energy), or a HF diet followed by weight reduction (WR). Mice fed a HF diet had significantly greater gonadal fat mass and higher whole blood glucose concentrations than mice fed an HC diet. Of the mice fed a high-fat diet, total body weight and serum insulin concentrations were greater in HF than in HFR. Microarray analysis revealed that HF vs. HC feeding resulted in global differences in adipocyte gene expression patterns. Although we identified genes whose expression was altered in both moderately and severely obese mice, there were also a large number of genes with altered expression only in severe obesity. Formerly obese, WR mice did not differ significantly from lean controls in total body weight or physiological measures. However, microarray analysis revealed distinctly different patterns of adipocyte gene expression. Furthermore, there were 398 genes with altered expression in HF mice that persisted in WR mice. Genes with persistently altered expression following obesity may play a role in rebound weight gain following weight reduction.

  7. Pregnancy complicated by obesity induces global transcript expression alterations in visceral and subcutaneous fat.

    PubMed

    Bashiri, Asher; Heo, Hye J; Ben-Avraham, Danny; Mazor, Moshe; Budagov, Temuri; Einstein, Francine H; Atzmon, Gil

    2014-08-01

    Maternal obesity is a significant risk factor for development of both maternal and fetal metabolic complications. Increase in visceral fat and insulin resistance is a metabolic hallmark of pregnancy, yet not much is known how obesity alters adipose cellular function and how this may contribute to pregnancy morbidities. We sought to identify alterations in genome-wide transcription expression in both visceral (omental) and abdominal subcutaneous fat deposits in pregnancy complicated by obesity. Visceral and abdominal subcutaneous fat deposits were collected from normal weight and obese pregnant women (n = 4/group) at the time of scheduled uncomplicated cesarean section. A genome-wide expression array (Affymetrix Human Exon 1.0 st platform), validated by quantitative real-time PCR, was utilized to establish the gene transcript expression profile in both visceral and abdominal subcutaneous fat in normal weight and obese pregnant women. Global alteration in gene expression was identified in pregnancy complicated by obesity. These regions of variations led to identification of indolethylamine N-methyltransferase, tissue factor pathway inhibitor-2, and ephrin type-B receptor 6, not previously associated with fat metabolism during pregnancy. In addition, subcutaneous fat of obese pregnant women demonstrated increased coding protein transcripts associated with apoptosis as compared to lean counterparts. Global alteration of gene expression in adipose tissue may contribute to adverse pregnancy outcomes associated with obesity.

  8. Pregnancy Complicated by Obesity Induces Global Transcript Expression Alterations in Visceral and Subcutaneous Fat

    PubMed Central

    Bashiri, Asher; Heo, Hye J.; Ben-Avraham, Danny; Mazor, Moshe; Budagov, Temuri; Einstein, Francine H.; Atzmon, Gil

    2014-01-01

    Maternal obesity is a significant risk factor for development of both maternal and fetal metabolic complications. Increase in visceral fat and insulin resistance is a metabolic hallmark of pregnancy, yet little is known how obesity alters adipose cellular function and how this may contribute to pregnancy morbidities. We sought to identify alterations in genome-wide transcription expression in both visceral (omental) and abdominal subcutaneous fat deposits in pregnancy complicated by obesity. Visceral and abdominal subcutaneous fat deposits were collected from normal weight and obese pregnant women (n=4/group) at time of scheduled uncomplicated cesarean section. A genome-wide expression array (Affymetrix Human Exon 1.0 st platform), validated by quantitative real-time PCR, was utilized to establish the gene transcript expression profile in both visceral and abdominal subcutaneous fat in normal weight and obese pregnant women. Global alteration in gene expression was identified in pregnancy complicated by obesity. These regions of variations lead to identification of indolethylamine N-methyltransferase (INMT), tissue factor pathway inhibitor-2 (TFPI-2), and ephrin type-B receptor 6 (EPHB6), not previously associated with fat metabolism during pregnancy. In addition, subcutaneous fat of obese pregnant women demonstrated increased coding protein transcripts associated with apoptosis compared to lean counterparts. Global alteration of gene expression in adipose tissue may contribute to adverse pregnancy outcomes associated with obesity. PMID:24696292

  9. Analysis of PTEN, BRAF and PI3K status for determination of benefit from cetuximab therapy in metastatic colorectal cancer patients refractory to chemotherapy with wild-type KRAS.

    PubMed

    Tural, Deniz; Batur, Sebnem; Erdamar, Sibel; Akar, Emre; Kepil, Nuray; Mandel, Nil Molinas; Serdengeçti, Süheyla

    2014-02-01

    We investigated predictive values of BRAF, PI3K and PTEN in cetuximab responses in KRAS wild-type (+) chemotherapy refractory, metastatic colorectal cancer (CRC) patients. Primary tumour tissues of 41 KRAS wild-type mCRC patients receiving cetuximab-based chemotherapy were investigated for PI3K, PTEN, KRAS and BRAF mutations. Progression-free survival (PFS) and overall survival (OS) periods were calculated with Kaplan-Meier method and the Cox proportional hazards model was used. PTEN and PI3K expressions were 63 and 42 %, respectively. BRAF mutation was observed as 9.8 % among patients. Tumours with BRAF mutation had statistically lower response rates (RR) for cetuximab-based treatment than tumours with BRAF wild type (0 vs. 58 %, p = 0.02). PTEN expressing tumours had statistically higher RR for cetuximab-based treatment than tumours with PTEN loss (42 vs. 12 %, p = 0.04). PI3K expression had worse significant effect on cetuximab RR than PI3K non-expressed tumours (15 vs. 44 %, p = 0.023). Median PFS was significantly longer in patients with PTEN expression (14 months) than in patients with PTEN loss (5 months) (HR, 0.4; p = 0.028). Median PFS was significantly longer in patients with PI3K non-expression (15.2 months) than in patients with PI3K expression (4.1 months) (HR, 0.31; p = 0.001). Significant difference in PFS and OS between patients with BRAF mutated and BRAF wild-type tumours was not detected. However, patients with PTEN expression had significantly longer OS (15.1 months) than patients with PTEN loss tumour (9.9 months) (HR, 0.34; p = 0.008). Patients without PI3K expression had significantly longer OS (18.2 months) than patients with PI3K expression (10.1 months) (HR, 0.27; p = 0.001). Multivariate analyses revealed that PTEN expression (HR, 0.48; p = 0.02) and absence of PI3K expression (HR, 0.2; p = 0.001) were independent prognostic factors for increased PFS. Similarly, PTEN overexpression (HR, 0.62; p = 0.03) and absence of PI3K expression (HR, 0

  10. PTEN enhances TNF-induced apoptosis through modulation of nuclear factor-{kappa}B signaling pathway in human glioma cells

    SciTech Connect

    Koul, Dimpy . E-mail: Dkoul@mdnderson.org; Takada, Yasunari; Shen, Ruijun; Aggarwal, Bharat B.; Yung, W.K. Alfred

    2006-11-17

    The PTEN tumor suppressor gene modulates cell growth and survival known to be regulated by the activation of the transcription factor NF{kappa}B, suggesting PTEN might affect the NF{kappa}B activation pathway. We found that PTEN inhibited NF{kappa}B activation induced by TNF. The suppression of NF{kappa}B activation correlated with sequential inhibition of the tumor necrosis factor-induced expression of NF{kappa}B-regulated anti-apoptotic (IAP1, IAP2, Bcl-2, Bcl-xL, cFLIP, Bfl-1/A1, and survivin) gene products. Downregulation of the antiapoptotic genes by PTEN increased TNF-induced apoptosis, as indicated by caspase activation, TUNEL, annexin staining, and esterase assay. We conclude that the ectopic expression of PTEN enhances TNF-induced apoptosis and downregulates the proliferation of glioma cells through the suppression of various molecules including NF{kappa}B, and various mediators of cellular survival and proliferation, and that this targets might be essential for its central role in the growth and survival of glioma cancer cells.

  11. E3 Ligase Nedd4 Promotes Axon Branching by Downregulating PTEN

    PubMed Central

    Drinjakovic, Jovana; Jung, Hosung; Campbell, Douglas S.; Strochlic, Laure; Dwivedy, Asha; Holt, Christine E.

    2010-01-01

    Summary Regulated protein degradation via the ubiquitin-proteasome system (UPS) plays a central role in building synaptic connections, yet little is known about either which specific UPS components are involved or UPS targets in neurons. We report that inhibiting the UPS in developing Xenopus retinal ganglion cells (RGCs) with a dominant-negative ubiquitin mutant decreases terminal branching in the tectum but does not affect long-range navigation to the tectum. We identify Nedd4 as a prominently expressed E3 ligase in RGC axon growth cones and show that disrupting its function severely inhibits terminal branching. We further demonstrate that PTEN, a negative regulator of the PI3K pathway, is a key downstream target of Nedd4: not only does Nedd4 regulate PTEN levels in RGC growth cones, but also, the decrease of PTEN rescues the branching defect caused by Nedd4 inhibition. Together our data suggest that Nedd4-regulated PTEN is a key regulator of terminal arborization in vivo. PMID:20159448

  12. Nanotherapeutics of PTEN Inhibitor with Mesoporous Silica Nanocarrier Effective for Axonal Outgrowth of Adult Neurons.

    PubMed

    Kim, Min Soo; El-Fiqi, Ahmed; Kim, Jong-Wan; Ahn, Hong-Sun; Kim, Hyukmin; Son, Young-Jin; Kim, Hae-Won; Hyun, Jung Keun

    2016-07-27

    Development of therapeutic strategies such as effective drug delivery is an urgent and yet unmet need for repair of damaged nervous systems. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) regulates axonal regrowth of central and peripheral nervous systems; its inhibition, meanwhile, facilitates axonal outgrowth of injured neurons. Here we show that nanotherapeutics based on mesoporous silica nanoparticles loading PTEN-inhibitor bisperoxovanadium (BpV) are effective for delivery of drug molecules and consequent improvement of axonal outgrowth. Mesoporous nanocarriers loaded BpV drug at large amount (27 μg per 1 mg of carrier), and released sustainably over 10 d. Nanocarrier-BpV treatment of primary neurons from the dorsal root ganglions (DRGs) of rats and mice at various concentrations induced them to actively take up the nanocomplexes with an uptake efficiency as high as 85%. The nanocomplex-administered neurons exhibited significantly enhanced axonal outgrowth compared with those treated with free-BpV drug. The expression of a series of proteins involved in PTEN inhibition and downstream signaling was substantially up-/down-regulated by the nanocarrier-BpV system. Injection of the nanocarriers into neural tissues (DRG, brain cortex, and spinal cord), moreover, demonstrated successful integration into neurons, glial cells, oligodendrocytes, and macrophages, suggesting the possible nanotherapeutics applications in vivo. Together, PTEN-inhibitor delivery via mesoporous nanocarriers can be considered a promising strategy for stimulating axonal regeneration in central and peripheral nervous systems. PMID:27386893

  13. Loss of PTEN promotes resistance to T cell-mediated immunotherapy

    PubMed Central

    Peng, Weiyi; Chen, Jie Qing; Liu, Chengwen; Malu, Shruti; Creasy, Caitlin; Tetzlaff, Michael T; Xu, Chunyu; McKenzie, Jodi A; Zhang, Chunlei; Liang, Xiaoxuan; Williams, Leila J; Deng, Wanleng; Chen, Guo; Mbofung, Rina; Lazar, Alexander J; Torres-Cabala, Carlos A; Cooper, Zachary A; Chen, Pei-Ling; Tieu, Trang N; Spranger, Stefani; Yu, Xiaoxing; Bernatchez, Chantale; Forget, Marie-Andree; Haymaker, Cara; Amaria, Rodabe; McQuade, Jennifer L; Glitza, Isabella C; Cascone, Tina; Li, Haiyan S; Kwong, Lawrence N; Heffernan, Timothy P; Hu, Jianhua; Bassett, Roland L; Bosenberg, Marcus W; Woodman, Scott E; Overwijk, Willem W; Lizée, Gregory; Roszik, Jason; Gajewski, Thomas F; Wargo, Jennifer A; Gershenwald, Jeffrey E; Radvanyi, Laszlo; Davies, Michael A; Hwu, Patrick

    2015-01-01

    T cell-mediated immunotherapies are promising cancer treatments. However, most patients still fail to respond to these therapies. The molecular determinants of immune resistance are poorly understood. We show that loss of PTEN in tumor cells in preclinical models of melanoma inhibits T cell-mediated tumor killing and decreases T cell trafficking into tumors. In patients, PTEN loss correlates with decreased T cell infiltration at tumor sites, reduced likelihood of successful T cell expansion from resected tumors, and inferior outcomes with PD-1 inhibitor therapy. PTEN loss in tumor cells increased the expression of immunosuppressive cytokines, resulting in decreased T cell infiltration in tumors, and inhibited autophagy, which decreased T cell-mediated cell death. Treatment with a selective PI3Kβ inhibitor improved the efficacy of both anti-PD-1 and anti-CTLA4 antibodies in murine models. Together these findings demonstrate that PTEN loss promotes immune resistance and support the rationale to explore combinations of immunotherapies and PI3K-AKT pathway inhibitors. PMID:26645196

  14. Roles of PTEN with DNA Repair in Parkinson’s Disease

    PubMed Central

    Ogino, Mako; Ichimura, Mayuko; Nakano, Noriko; Minami, Akari; Kitagishi, Yasuko; Matsuda, Satoru

    2016-01-01

    Oxidative stress is considered to play key roles in aging and pathogenesis of many neurodegenerative diseases such as Parkinson’s disease, which could bring DNA damage by cells. The DNA damage may lead to the cell apoptosis, which could contribute to the degeneration of neuronal tissues. Recent evidence suggests that PTEN (phosphatase and tensin homolog on chromosome 10) may be involved in the pathophysiology of the neurodegenerative disorders. Since PTEN expression appears to be one dominant determinant of the neuronal cell death, PTEN should be a potential molecular target of novel therapeutic strategies against Parkinson’s disease. In addition, defects in DNA damage response and DNA repair are often associated with modulation of hormone signaling pathways. Especially, many observations imply a role for estrogen in a regulation of the DNA repair action. In the present review, we have attempted to summarize the function of DNA repair molecules at a viewpoint of the PTEN signaling pathway and the hormone related functional modulation of cells, providing a broad interpretation on the molecular mechanisms for treatment of Parkinson’s disease. Particular attention will be paid to the mechanisms proposed to explain the health effects of food ingredients against Parkinson’s disease related to reduce oxidative stress for an efficient therapeutic intervention. PMID:27314344

  15. miR-382 targeting PTEN-Akt axis promotes liver regeneration

    PubMed Central

    Wang, Fei; Dimitrova-Shumkovska, Jasmina; Xiang, Yang; Zhao, Yingying; Liu, Jingqi; Xiao, Junjie; Yang, Changqing

    2016-01-01

    Liver regeneration is a highly orchestrated process which can be regulated by microRNAs (miRNAs, miRs), though the mechanisms are largely unclear. This study was aimed to identify miRNAs responsible for hepatocyte proliferation during liver regeneration. Here we detected a marked elevation of miR-382 in the mouse liver at 48 hrs after partial hepatectomy (PH-48h) using microarray analysis and qRT-PCRs. miR-382 overexpression accelerated the proliferation and the G1 to S phase transition of the cell cycle both in mouse NCTC1469 and human HL7702 normal liver cells, while miR-382 downregulation had inverse effects. Moreover, miR-382 negatively regulated PTEN expression and increased Akt phosphorylation both in vitro and in vivo. Using PTEN siRNA and Akt activator/inhibitor, we further found that PTEN inhibition and Akt phosphorylation were essential for mediating the promotive effect of miR-382 in the proliferation and cell growth of hepatocytes. Collectively, our findings identify miR-382 as a promoter for hepatocyte proliferation and cell growth via targeting PTEN-Akt axis which might be a novel therapeutic target to enhance liver regeneration capability. PMID:26636539

  16. Altered expression of AT-rich interactive domain 1A in hepatocellular carcinoma.

    PubMed

    Abe, Hiroyuki; Hayashi, Akimasa; Kunita, Akiko; Sakamoto, Yoshihiro; Hasegawa, Kiyoshi; Shibahara, Junji; Kokudo, Norihiro; Fukayama, Masashi

    2015-01-01

    AT-rich interactive domain 1A (ARID1A) is a subunit of the Switch/Sucrose non-fermentable (SWI/SNF) chromatin remodeling complex. Recently, genome-wide whole exome sequencing revealed frequent mutations of ARID1A in hepatocellular carcinoma, but clinicopathological significance of ARID1A alteration has not been clarified yet. In this study, expression of ARID1A was investigated immunohistochemically in 290 cases of hepatocellular carcinomas. In the evaluation of tissue microarrays, cases of ARID1A alteration (63 total cases, 21.7%) consisted of 11 (3.8%) cases showing loss of expression and 52 (17.9%) with weak expression. Alteration of ARID1A was correlated with larger tumor size (P=0.034) and well or moderate differentiation of tumor histology (P=0.035). There was no significant correlation with age, sex, cirrhosis, TNM stage, tumor size, number of tumors, vascular invasion, patient survival, HBV infection, HCV infection, heavy use of alcohol, nor diabetes mellitus. EBER in situ hybridization was negative in all 11 cases with loss of ARID1A. Altered expression of ARID1A was inversely correlated with nuclear expression of p53 (P=0.018) or beta-catenin (P=0.025). There was some heterogeneity of ARID1A alteration within each case, and immunohistochemistry of the whole sections demonstrated that four of 11 cases with loss of ARID1A in TMA analysis showed localized positive area within the tumor. Alteration of ARID1A may accelerate tumor growth in a subset of hepatocellular carcinoma, and this pathway may be distinct from p53 and beta-catenin pathways. PMID:26045782

  17. PTEN permits acute increases in D3-phosphoinositide levels following TCR stimulation but inhibits distal signaling events by reducing the basal activity of Akt.

    PubMed

    Seminario, Maria-Cristina; Precht, Patricia; Bunnell, Stephen C; Warren, Sarah E; Morris, Christa M; Taub, Dennis; Wange, Ronald L

    2004-11-01

    Phosphoinositide 3-kinase (PI3K) is important in TCR signaling. PI3K generates phosphatidylinositol 3, 4, 5-trisphosphate (PI-3,4,5-P3), which regulates membrane localization and/or activity of multiple signaling proteins. PTEN (phosphatase and tensin homologue deleted on chromosome 10) opposes PI3K, reversing this reaction. Maintaining the balance between these two enzymes is important for normal T cell function. Here we use the PTEN-null Jurkat T cell line to address the role of PTEN in modulating proximal and distal TCR-signaling events. PTEN expression at levels that restored low basal Akt phosphorylation (an indicator of PI-3,4,5-P3 levels), but which were not themselves cytotoxic, had minimal effect on TCR-stimulated activation of phospholipase Cgamma1 and Ca2+ flux, but reduced the duration of extracellular signal-regulated kinase (Erk) activation. Distal signaling events, including nuclear factor of activated T cells (NFAT) activation, CD69 expression and IL-2 production, were all inhibited by PTEN expression. Notably, PTEN did not block TCR-stimulated PI-3,4,5-P3 accumulation. The effect of PTEN on distal TCR signaling events was strongly correlated with the loss of the constitutive Akt activation and glycogen synthase kinase-3 (GSK3) inhibition that is typical of Jurkat cells, and could be reversed by expression of activated Akt or pharmacologic inhibition of GSK3. These results suggest that PTEN acts in T cells primarily to control basal PI-3,4,5-P3 levels, rather than opposing PI3K acutely during TCR stimulation.

  18. Formaldehyde exposure alters miRNA expression profiles in the olfactory bulb.

    PubMed

    Li, Guifa; Yang, Jing; Ling, Shucai

    2015-01-01

    It has been reported that inhaling formaldehyde (FA) causes damage to the central nervous system. However, it is unclear whether FA can disturb the function of the olfactory bulb. Using a microarray, we found that FA inhalation altered the miRNA expression profile. Functional enrichment analysis of the predicted targets of the changed miRNA showed that the enrichment canonical pathways and networks associated with cancer and transcriptional regulation. FA exposure disrupts miRNA expression profiles within the olfactory bulb.

  19. Expression of AS3MT alters transcriptional profiles in human urothelial cells exposed to arsenite.

    PubMed

    Hester, Sd; Drobná, Z; Andrews, Dmk; Liu, J; Waalkes, Mp; Thomas, Dj; Styblo, M

    2009-01-01

    Inorganic arsenic (iAs) is an environmental toxicant and human carcinogen. The enzymatic methylation of iAs that is catalyzed by arsenic (+3 oxidation state)-methyltransferase (AS3MT) generates reactive methylated intermediates that contribute to the toxic and carcinogenic effects of iAs. We have shown that clonal human urothelial cells (UROtsa/F35) that express rat AS3MT and methylate iAs are more susceptible to acute toxicity of arsenite (iAs(III)) than parental UROtsa cells that do not express AS3MT and do not methylate iAs. The current work examines transcriptional changes associated with AS3MT expression and identifies specific categories of genes expressed in UROtsa and UROtsa/F35 cells in response to a 24-h exposure to 1 or 50 microM iAs(III). Here, the expression of 21,073 genes was assessed using Agilent Human 1A(V2) arrays. Venn analysis showed marked concentration-dependent differences between gene expression patterns in UROtsa and UROTsa/F35 cells exposed to iAs(III). Among 134 genes altered by exposure to subtoxic 1 microM iAs(III), only 14 were shared by both cell lines. Exposure to cytotoxic 50 microM iAs(III) uniquely altered 1389 genes in UROtsa/F35 and 649 genes in UROtsa cells; 5033 altered genes were associated with the chemical alone. In UROtsa, but not UROtsa/F35 cells exposure to 1 microM iAs(III) altered expression of genes associated with cell adhesion. In contrast, expression of genes involved in cell cycle regulation was significantly altered in UROtsa/F35 cells at this exposure level. At 50 microM iAs(III), pathways regulating cell cycle, cell death, transcription, and metabolism were affected in both cell lines. However, only Urotsa/F35 cells showed numerous G-protein and kinase pathway alterations as well as alterations in pathways involved in cell growth and differentiation. These data link the AS3MT-catalyzed methylation of iAs to specific genomic responses in human cells exposed to iAs(III). Further analysis of these responses will

  20. Microemboli alter the acute stress response and cause prolonged expression of MCP-1 in the hippocampus.

    PubMed

    Nemeth, Christina L; Neigh, Gretchen N

    2015-04-01

    Microvascular ischemia is linked to cardiovascular disease pathology, as well as alterations in mood and cognition. Ischemia activates the hypothalamic-pituitary-adrenal (HPA) axis and through chronic activation, alters HPA axis function. Dysregulation of the HPA axis can lead to the chronic release of glucocorticoids, a hyper-inflammatory cerebral response, cell damage, and changes in behavior. Although the interactions between injury and HPA axis activity have been established in global ischemia, HPA-related repercussions of diffuse ischemic damage and subsequent inflammation have not been assessed. The current study used a rat model of microsphere embolism (ME) ischemia to test the hypothesis that microvascular ischemia would lead to long term alterations in HPA axis function and inflammatory activity. Furthermore, given the pro-inflammatory nature of chronic stress, we assessed the implications of chronic stress for gene expression of inflammatory factors and key components of the glucocorticoid receptor response, following microvascular ischemia. Results indicated that ME altered the response to an acute stress fourteen days following ME injury and increased hippocampal expression of monocyte chemoattractant protein 1 (Mcp-1) as long as 4 weeks following ME injury, without concomitant effects on gene expression of the glucocorticoid receptor or its co-chaperones. Furthermore, no exacerbative effects of chronic stress exposure were observed following ME injury beyond the effects of ME injury alone. Together, these results indicate that ME injury is sufficient to alter both HPA axis activity and cerebral inflammation for a prolonged period of time following injury.

  1. Mutant U2AF1 Expression Alters Hematopoiesis and Pre-mRNA Splicing In Vivo

    PubMed Central

    Shirai, Cara Lunn; Ley, James N.; White, Brian S.; Kim, Sanghyun; Tibbitts, Justin; Shao, Jin; Ndonwi, Matthew; Wadugu, Brian; Duncavage, Eric J.; Okeyo-Owuor, Theresa; Liu, Tuoen; Griffith, Malachi; McGrath, Sean; Magrini, Vincent; Fulton, Robert S.; Fronick, Catrina; O’Laughlin, Michelle; Graubert, Timothy A.; Walter, Matthew J.

    2015-01-01

    SUMMARY Heterozygous somatic mutations in the spliceosome gene U2AF1 occur in ~11% of patients with myelodysplastic syndromes (MDS), the most common adult myeloid malignancy. It is unclear how these mutations contribute to disease. We examined in vivo hematopoietic consequences of the most common U2AF1 mutation using a doxycycline-inducible transgenic mouse model. Mice expressing mutant U2AF1(S34F) display altered hematopoiesis and changes in pre-mRNA splicing in hematopoietic progenitor cells by whole transcriptome analysis (RNA-seq). Integration with human RNA-seq datasets determined that common mutant U2AF1-induced splicing alterations are enriched in RNA processing genes, ribosomal genes, and recurrently-mutated MDS and acute myeloid leukemia-associated genes. These findings support the hypothesis that mutant U2AF1 alters downstream gene isoform expression, thereby contributing to abnormal hematopoiesis in MDS patients. PMID:25965570

  2. Methyl-ß-cyclodextrin alters adipokine gene expression and glucose metabolism in swine adipose tissue

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was designed to determine if metabolic stress as induced by methyl-ß-cyclodextrin (MCD) can alter cytokine expression in neonatal swine adipose tissue explants. Subcutaneous adipose tissue explants (100 ± 10 mg) were prepared from 21 day old pigs. Explants were incubated in medium 199 s...

  3. POTENTIAL ALTERATIONS IN GENE EXPRESSION ASSOCIATED WITH CARCINOGEN EXPOSURE IN MYA ARENARIA

    EPA Science Inventory

    Gonadal cancers in soft-shell clams (Mya arenaria) have been found at high prevalences (20-40%) in populations in eastern Maine. The aetiology of these tumours is unknown. We hypothesized that gene expression would be altered in gonadal tumours and that examination of gene expres...

  4. Overexpression of Bmi-1 contributes to the invasion and metastasis of hepatocellular carcinoma by increasing the expression of matrix metalloproteinase (MMP)‑2, MMP-9 and vascular endothelial growth factor via the PTEN/PI3K/Akt pathway.

    PubMed

    Li, Xiaolei; Yang, Zhaoxu; Song, Wenjie; Zhou, Liang; Li, Qingjun; Tao, Kaishan; Zhou, Jingshi; Wang, Xing; Zheng, Zhigang; You, Nan; Dou, Kefeng; Li, Haimin

    2013-09-01

    Hepatocellular carcinoma (HCC) is one of the most common malignant tumours and it carries a poor prognosis due to a high rate of recurrence or metastasis after surgery. Bmi-1 plays a significant role in the growth and metastasis of many solid tumours. However, the exact mechanisms underlying Bmi-1-mediated cell invasion and metastasis, especially in HCC, are not yet known. In the present study, we sought to evaluate the expression of Bmi-1 in HCC samples and its relationship with clinicopathological characteristics and prognostic value, we also investigated related mechanisms underlying Bmi-1-mediated cell invasion in HCC. Our results showed that Bmi-1 is upregulated in HCC tissues compared to matched non-cancer liver tissues; and its expression is positively associated with tumour size, metastasis, venous invasion and AJCC TNM stage, respectively; multivariate analysis showed that high expression of Bmi-1 was an independent prognostic factor for overall survival. In addition, the shRNA-mediated inhibition of Bmi-1 reduced the invasiveness of two HCC cell lines in vitro by upregulating phosphatase and the tensin homolog deleted on chromosome 10 (PTEN) expression, inhibiting the phosphatidylinositol 3-kinase (PI3K)/Akt signalling pathway and downregulating the expression and activities of matrix metalloproteinase (MMP)-2 and MMP-9 and vascular endothelial growth factor (VEGF). These data demonstrate that Bmi-1 plays a vital role in HCC invasion and that Bmi-1 is a potential therapeutic target for HCC.

  5. MicroRNA-22 promotes cell survival upon UV radiation by repressing PTEN

    SciTech Connect

    Tan, Guangyun; Shi, Yuling; Wu, Zhao-Hui

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer miR-22 is induced in cells treated with UV radiation. Black-Right-Pointing-Pointer ATM is required for miR-22 induction in response to UV. Black-Right-Pointing-Pointer miR-22 targets 3 Prime -UTR of PTEN to repress its expression in UV-treated cells. Black-Right-Pointing-Pointer Upregulated miR-22 inhibits apoptosis in cells exposed to UV. -- Abstract: DNA damage response upon UV radiation involves a complex network of cellular events required for maintaining the homeostasis and restoring genomic stability of the cells. As a new class of players involved in DNA damage response, the regulation and function of microRNAs in response to UV remain poorly understood. Here we show that UV radiation induces a significant increase of miR-22 expression, which appears to be dependent on the activation of DNA damage responding kinase ATM (ataxia telangiectasia mutated). Increased miR-22 expression may result from enhanced miR-22 maturation in cells exposed to UV. We further found that tumor suppressor gene phosphatase and tensin homolog (PTEN) expression was inversely correlated with miR-22 induction and UV-induced PTEN repression was attenuated by overexpression of a miR-22 inhibitor. Moreover, increased miR-22 expression significantly inhibited the activation of caspase signaling cascade, leading to enhanced cell survival upon UV radiation. Collectively, these results indicate that miR-22 is an important player in the cellular stress response upon UV radiation, which may promote cell survival via the repression of PTEN expression.

  6. Expression of FSHD-related DUX4-FL alters proteostasis and induces TDP-43 aggregation

    PubMed Central

    Homma, Sachiko; Beermann, Mary Lou; Boyce, Frederick M; Miller, Jeffrey Boone

    2015-01-01

    Objective Pathogenesis in facioscapulohumeral muscular dystrophy (FSHD) appears to be due to aberrant expression, particularly in skeletal muscle nuclei, of the full-length isoform of DUX4 (DUX4-FL). Expression of DUX4-FL is known to alter gene expression and to be cytotoxic, but cell responses to DUX4-FL are not fully understood. Our study was designed to identify cellular mechanisms of pathogenesis caused by DUX4-FL expression. Methods We used human myogenic cell cultures to analyze the effects of DUX4-FL when it was expressed either from its endogenous promoter in FSHD cells or by exogenous expression using BacMam vectors. We focused on determining the effects of DUX4-FL on protein ubiquitination and turnover and on aggregation of TDP-43. Results Human FSHD myotubes with endogenous DUX4-FL expression showed both altered nuclear and cytoplasmic distributions of ubiquitinated proteins and aggregation of TDP-43 in DUX4-FL-expressing nuclei. Similar changes were found upon exogenous expression of DUX4-FL, but were not seen upon expression of the non-toxic short isoform DUX4-S. DUX4-FL expression also inhibited protein turnover in a model system and increased the amounts of insoluble ubiquitinated proteins and insoluble TDP-43. Finally, inhibition of the ubiquitin–proteasome system with MG132 produced TDP-43 aggregation similar to DUX4-FL expression. Interpretations Our results identify DUX4-FL-induced inhibition of protein turnover and aggregation of TDP-43, which are pathological changes also found in diseases such as amyotrophic lateral sclerosis and inclusion body myopathy, as potential pathological mechanisms in FSHD. PMID:25750920

  7. The RhoA-ROCK-PTEN pathway as a molecular switch for anchorage dependent cell behavior.

    PubMed

    Yang, Seungwon; Kim, Hyun-Man

    2012-04-01

    The proliferation of anchorage-dependent cells of mesenchymal origin requires the attachment of the cells to substrates. Thus, cells that are poorly attached to substrates exhibit retarded cell cycle progression or apoptotic death. A major disadvantage of most polymers used in tissue engineering is their hydrophobicity; hydrophobic surfaces do not allow cells to attach firmly and, therefore, do not allow normal proliferation rates. In this study, we investigated the molecular mechanism underlying the reduced proliferation rate of cells that are poorly attached to substrates. There was an inverse relationship between the activity of the small GTPase RhoA (RhoA) and the cell proliferation rate. RhoA activity correlated inversely with the strength of cell adhesion to the substrates. The high RhoA activity in the cells poorly attached to substrates caused an increase in the activity of Rho-associated kinase (ROCK), a well-known effector of RhoA that upregulated the activity of phosphatase and tensin homolog (PTEN). The resulting activated PTEN downregulated Akt activity, which is essential for cell proliferation. Thus, the cells that were poorly attached to substrates showed low levels of cell proliferation because the RhoA-ROCK-PTEN pathway was hyperactive. In addition, RhoA activity seemed to be related to focal adhesion kinase (FAK) activity. Weak FAK activity in these poorly attached cells failed to downregulate the high RhoA activity that restrained cell proliferation. Interestingly, reducing the expression of any component of the RhoA-ROCK-PTEN pathway rescued the proliferation rate without physico-chemical surface modifications. Based on these results, we suggest that the RhoA-ROCK-PTEN pathway acts as a molecular switch to control cell proliferation and determine anchorage dependence. In cells that are poorly attached to substrates, its inhibition is sufficient to restore cell proliferation without the need for physico-chemical modification of the material

  8. The role of phosphoinositide-3 kinase and PTEN in cardiovascular physiology and disease.

    PubMed

    Oudit, Gavin Y; Sun, Hui; Kerfant, Benoit-Gilles; Crackower, Michael A; Penninger, Josef M; Backx, Peter H

    2004-08-01

    Phosphoinositide-3 kinases (PI3Ks) are a family of evolutionary conserved lipid kinases that mediate many cellular responses in both physiologic and pathophysiologic states. Class I PI3K can be activated by either receptor tyrosine kinase (RTK)/cytokine receptor activation (class I(A)) or G-protein-coupled receptors (GPCR) (class I(B)). Once activated PI3Ks generate phosphatidylinositols (PtdIns) (3,4,5)P(3) leading to the recruitment and activation of Akt/protein kinase B (PKB), PDK1 and monomeric G-proteins (e.g. Rac-GTPases), which then activate a range of downstream targets including glycogen synthase kinase-3beta (GSK-3beta), mammalian target of rapamycin (mTOR), p70S6 kinase, endothelial nitric oxide synthase (eNOS) and several anti-apoptotic effectors. Class I(A) (PI3Kalpha, beta and delta) and class I(B) (PI3Kgamma) PI3Ks mediate distinct phenotypes in the heart and under negative control by the 3'-lipid phosphatase, phosphatase and tensin homolog on chromosome ten (PTEN) which dephosphorylate PtdIns(3,4,5)P(3) into PtdIns(4,5)P(2). PI3Kalpha, gamma and PTEN are expressed in cardiomyocytes, fibroblasts, endothelial cells and vascular smooth muscle cells where they modulate cell survival/apoptosis, hypertrophy, contractility, metabolism and mechanotransduction. Several transgenic and knockout models support a fundamental role of PI3K/PTEN signaling in the regulation of myocardial contractility and hypertrophy. Consequently the PI3K/PTEN signaling pathways are involved in a wide variety of diseases including cardiac hypertrophy, heart failure, preconditioning and hypertension. In this review, we discuss the biochemistry and molecular biology of PI3K (class I isoforms) and PTEN and their critical role in cardiovascular physiology and diseases.

  9. PTEN stabilizes TOP2A and regulates the DNA decatenation.

    PubMed

    Kang, Xi; Song, Chang; Du, Xiao; Zhang, Cong; Liu, Yu; Liang, Ling; He, Jinxue; Lamb, Kristy; Shen, Wen H; Yin, Yuxin

    2015-12-10

    PTEN is a powerful tumor suppressor that antagonizes the cytoplasmic PI3K-AKT pathway and suppresses cellular proliferation. PTEN also plays a role in the maintenance of genomic stability in the nucleus. Here we report that PTEN facilitates DNA decatenation and controls a decatenation checkpoint. Catenations of DNA formed during replication are decatenated by DNA topoisomerase II (TOP2), and this process is actively monitored by a decatenation checkpoint in G2 phase. We found that PTEN deficient cells form ultra-fine bridges (UFBs) during anaphase and these bridges are generated as a result of insufficient decatenation. We show that PTEN is physically associated with a decatenation enzyme TOP2A and that PTEN influences its stability through OTUD3 deubiquitinase. In the presence of PTEN, ubiquitination of TOP2A is inhibited by OTUD3. Deletion or deficiency of PTEN leads to down regulation of TOP2A, dysfunction of the decatenation checkpoint and incomplete DNA decatenation in G2 and M phases. We propose that PTEN controls DNA decatenation to maintain genomic stability and integrity.

  10. Decreased aggression and increased repetitive behavior in Pten haploinsufficient mice.

    PubMed

    Clipperton-Allen, A E; Page, D T

    2015-02-01

    Aggression is an aspect of social behavior that can be elevated in some individuals with autism spectrum disorder (ASD) and a concern for peers and caregivers. Mutations in Phosphatase and tensin homolog (PTEN), one of several ASD risk factors encoding negative regulators of the PI3K-Akt-mTOR pathway, have been reported in individuals with ASD and comorbid macrocephaly. We previously showed that a mouse model of Pten germline haploinsufficiency (Pten(+/-) ) has selective deficits, primarily in social behavior, along with broad overgrowth of the brain. Here, we further examine the social behavior of Pten(+/-) male mice in the resident-intruder test of aggression, using a comprehensive behavioral analysis to obtain an overall picture of the agonistic, non-agonistic and non-social behavior patterns of Pten(+/-) mice during a free interaction with a novel conspecific. Pten(+/-) male mice were involved in less aggression than their wild-type littermates. Pten(+/-) mice also performed less social investigation, including anogenital investigation and approaching and/or attending to the intruder, which is consistent with our previous finding of decreased sociability in the social approach test. In contrast to these decreases in social behaviors, Pten(+/-) mice showed increased digging. In summary, we report decreased aggression and increased repetitive behavior in Pten(+/-) mice, thus extending our characterization of this model of an ASD risk factor that features brain overgrowth and social deficits.

  11. PTEN stabilizes TOP2A and regulates the DNA decatenation

    PubMed Central

    Kang, Xi; Song, Chang; Du, Xiao; Zhang, Cong; Liu, Yu; Liang, Ling; He, Jinxue; Lamb, Kristy; Shen, Wen H.; Yin, Yuxin

    2015-01-01

    PTEN is a powerful tumor suppressor that antagonizes the cytoplasmic PI3K-AKT pathway and suppresses cellular proliferation. PTEN also plays a role in the maintenance of genomic stability in the nucleus. Here we report that PTEN facilitates DNA decatenation and controls a decatenation checkpoint. Catenations of DNA formed during replication are decatenated by DNA topoisomerase II (TOP2), and this process is actively monitored by a decatenation checkpoint in G2 phase. We found that PTEN deficient cells form ultra-fine bridges (UFBs) during anaphase and these bridges are generated as a result of insufficient decatenation. We show that PTEN is physically associated with a decatenation enzyme TOP2A and that PTEN influences its stability through OTUD3 deubiquitinase. In the presence of PTEN, ubiquitination of TOP2A is inhibited by OTUD3. Deletion or deficiency of PTEN leads to down regulation of TOP2A, dysfunction of the decatenation checkpoint and incomplete DNA decatenation in G2 and M phases. We propose that PTEN controls DNA decatenation to maintain genomic stability and integrity. PMID:26657567

  12. Pten regulates Aurora-A and cooperates with Fbxw7 in modulating radiation-induced tumor development

    PubMed Central

    Kwon, Yong-Won; Kim, Il-Jin; Wu, Di; Lu, Jing; Stock, William A; Liu, Yueyong; Huang, Yurong; Kang, Hio Chung; DelRosario, Reyno; Jen, Kuang-Yu; Perez-Losada, Jesus; Wei, Guangwei; Balmain, Allan; Mao, Jian-Hua

    2012-01-01

    The Aurora-A kinase gene is frequently amplified and/or over-expressed in a variety of human cancers, leading to major efforts to develop therapeutic agents targeting this pathway. Here we demonstrate that Aurora-A is targeted for ubiquitination and subsequent degradation by the F-box protein FBXW7 in a process that is regulated by GSK3β. Using a series of truncated Aurora-A proteins and site directed mutagenesis, we identified distinct FBXW7 and GSK3β binding sites in Aurora-A. Mutation of critical residues in either site substantially disrupts degradation of Aurora-A. Furthermore, we show that loss of Pten results in the stabilization of Aurora-A by attenuating FBXW7-dependent degradation of Aurora-A through the AKT/GSK3β pathway. Moreover, radiation-induced tumor latency is significantly shortened in Fbxw7+/− Pten+/− mice as compared to either Fbxw7+/− or Pten+/− mice, indicating that Fbxw7 and Pten appear to cooperate in suppressing tumorigenesis. Our results establish a novel posttranslational regulatory network in which the Pten and Fbxw7 pathways appear to converge on the regulation of Aurora-A level. PMID:22513362

  13. Alcohol Consumption Modulates Host Defense in Rhesus Macaques by Altering Gene Expression in Circulating Leukocytes.

    PubMed

    Barr, Tasha; Girke, Thomas; Sureshchandra, Suhas; Nguyen, Christina; Grant, Kathleen; Messaoudi, Ilhem

    2016-01-01

    Several lines of evidence indicate that chronic alcohol use disorder leads to increased susceptibility to several viral and bacterial infections, whereas moderate alcohol consumption decreases the incidence of colds and improves immune responses to some pathogens. In line with these observations, we recently showed that heavy ethanol intake (average blood ethanol concentrations > 80 mg/dl) suppressed, whereas moderate alcohol consumption (blood ethanol concentrations < 50 mg/dl) enhanced, T and B cell responses to modified vaccinia Ankara vaccination in a nonhuman primate model of voluntary ethanol consumption. To uncover the molecular basis for impaired immunity with heavy alcohol consumption and enhanced immune response with moderate alcohol consumption, we performed a transcriptome analysis using PBMCs isolated on day 7 post-modified vaccinia Ankara vaccination, the earliest time point at which we detected differences in T cell and Ab responses. Overall, chronic heavy alcohol consumption reduced the expression of immune genes involved in response to infection and wound healing and increased the expression of genes associated with the development of lung inflammatory disease and cancer. In contrast, chronic moderate alcohol consumption upregulated the expression of genes involved in immune response and reduced the expression of genes involved in cancer. To uncover mechanisms underlying the alterations in PBMC transcriptomes, we profiled the expression of microRNAs within the same samples. Chronic heavy ethanol consumption altered the levels of several microRNAs involved in cancer and immunity and known to regulate the expression of mRNAs differentially expressed in our data set.

  14. Alcohol Consumption Modulates Host Defense in Rhesus Macaques by Altering Gene Expression in Circulating Leukocytes.

    PubMed

    Barr, Tasha; Girke, Thomas; Sureshchandra, Suhas; Nguyen, Christina; Grant, Kathleen; Messaoudi, Ilhem

    2016-01-01

    Several lines of evidence indicate that chronic alcohol use disorder leads to increased susceptibility to several viral and bacterial infections, whereas moderate alcohol consumption decreases the incidence of colds and improves immune responses to some pathogens. In line with these observations, we recently showed that heavy ethanol intake (average blood ethanol concentrations > 80 mg/dl) suppressed, whereas moderate alcohol consumption (blood ethanol concentrations < 50 mg/dl) enhanced, T and B cell responses to modified vaccinia Ankara vaccination in a nonhuman primate model of voluntary ethanol consumption. To uncover the molecular basis for impaired immunity with heavy alcohol consumption and enhanced immune response with moderate alcohol consumption, we performed a transcriptome analysis using PBMCs isolated on day 7 post-modified vaccinia Ankara vaccination, the earliest time point at which we detected differences in T cell and Ab responses. Overall, chronic heavy alcohol consumption reduced the expression of immune genes involved in response to infection and wound healing and increased the expression of genes associated with the development of lung inflammatory disease and cancer. In contrast, chronic moderate alcohol consumption upregulated the expression of genes involved in immune response and reduced the expression of genes involved in cancer. To uncover mechanisms underlying the alterations in PBMC transcriptomes, we profiled the expression of microRNAs within the same samples. Chronic heavy ethanol consumption altered the levels of several microRNAs involved in cancer and immunity and known to regulate the expression of mRNAs differentially expressed in our data set. PMID:26621857

  15. Influenza matrix protein 2 alters CFTR expression and function through its ion channel activity.

    PubMed

    Londino, James D; Lazrak, Ahmed; Jurkuvenaite, Asta; Collawn, James F; Noah, James W; Matalon, Sadis

    2013-05-01

    The human cystic fibrosis transmembrane conductance regulator (CFTR) is a cyclic AMP-activated chloride (Cl(-)) channel in the lung epithelium that helps regulate the thickness and composition of the lung epithelial lining fluid. We investigated whether influenza M2 protein, a pH-activated proton (H(+)) channel that traffics to the plasma membrane of infected cells, altered CFTR expression and function. M2 decreased CFTR activity in 1) Xenopus oocytes injected with human CFTR, 2) epithelial cells (HEK-293) stably transfected with CFTR, and 3) human bronchial epithelial cells (16HBE14o-) expressing native CFTR. This inhibition was partially reversed by an inhibitor of the ubiquitin-activating enzyme E1. Next we investigated whether the M2 inhibition of CFTR activity was due to an increase of secretory organelle pH by M2. Incubation of Xenopus oocytes expressing CFTR with ammonium chloride or concanamycin A, two agents that alkalinize the secretory pathway, inhibited CFTR activity in a dose-dependent manner. Treatment of M2- and CFTR-expressing oocytes with the M2 ion channel inhibitor amantadine prevented the loss in CFTR expression and activity; in addition, M2 mutants, lacking the ability to transport H(+), did not alter CFTR activity in Xenopus oocytes and HEK cells. Expression of an M2 mutant retained in the endoplasmic reticulum also failed to alter CFTR activity. In summary, our data show that M2 decreases CFTR activity by increasing secretory organelle pH, which targets CFTR for destruction by the ubiquitin system. Alteration of CFTR activity has important consequences for fluid regulation and may potentially modify the immune response to viral infection.

  16. Influenza matrix protein 2 alters CFTR expression and function through its ion channel activity

    PubMed Central

    Londino, James D.; Lazrak, Ahmed; Jurkuvenaite, Asta; Collawn, James F.; Noah, James W.

    2013-01-01

    The human cystic fibrosis transmembrane conductance regulator (CFTR) is a cyclic AMP-activated chloride (Cl−) channel in the lung epithelium that helps regulate the thickness and composition of the lung epithelial lining fluid. We investigated whether influenza M2 protein, a pH-activated proton (H+) channel that traffics to the plasma membrane of infected cells, altered CFTR expression and function. M2 decreased CFTR activity in 1) Xenopus oocytes injected with human CFTR, 2) epithelial cells (HEK-293) stably transfected with CFTR, and 3) human bronchial epithelial cells (16HBE14o−) expressing native CFTR. This inhibition was partially reversed by an inhibitor of the ubiquitin-activating enzyme E1. Next we investigated whether the M2 inhibition of CFTR activity was due to an increase of secretory organelle pH by M2. Incubation of Xenopus oocytes expressing CFTR with ammonium chloride or concanamycin A, two agents that alkalinize the secretory pathway, inhibited CFTR activity in a dose-dependent manner. Treatment of M2- and CFTR-expressing oocytes with the M2 ion channel inhibitor amantadine prevented the loss in CFTR expression and activity; in addition, M2 mutants, lacking the ability to transport H+, did not alter CFTR activity in Xenopus oocytes and HEK cells. Expression of an M2 mutant retained in the endoplasmic reticulum also failed to alter CFTR activity. In summary, our data show that M2 decreases CFTR activity by increasing secretory organelle pH, which targets CFTR for destruction by the ubiquitin system. Alteration of CFTR activity has important consequences for fluid regulation and may potentially modify the immune response to viral infection. PMID:23457187

  17. Drought response transcriptomes are altered in poplar with reduced tonoplast sucrose transporter expression

    PubMed Central

    Xue, Liang-Jiao; Frost, Christopher J.; Tsai, Chung-Jui; Harding, Scott A.

    2016-01-01

    Transgenic Populus tremula x alba (717-1B4) plants with reduced expression of a tonoplast sucrose efflux transporter, PtaSUT4, exhibit reduced shoot growth compared to wild type (WT) under sustained mild drought. The present study was undertaken to determine whether SUT4-RNAi directly or indirectly altered poplar predisposition and/or response to changes in soil water availability. While sucrose and hexose levels were constitutively elevated in shoot organs, expression responses to drought were most altered in the root tips of SUT4-RNAi plants. Prior to any drought treatment, constitutively elevated transcript levels of abscisic acid biosynthetic genes and bark/vegetative storage proteins suggested altered metabolism in root tips of RNAi plants. Stronger drought-stimulation of stress-inducible genes encoding late-embryogenesis-abundant proteins in transgenic roots was consistent with increased vulnerability to soil drying. Transcript evidence suggested an RNAi effect on intercellular water trafficking by aquaporins in stem xylem during soil drying and recovery. Co-expression network analysis predicted altered integration of abscisic acid sensing/signaling with ethylene and jasmonate sensing/signaling in RNAi compared to WT roots. The overall conclusion is that steepened shoot-root sugar gradient in RNAi plants increased sensitivity of root tips to decreasing soil water availability. PMID:27641356

  18. Drought response transcriptomes are altered in poplar with reduced tonoplast sucrose transporter expression.

    PubMed

    Xue, Liang-Jiao; Frost, Christopher J; Tsai, Chung-Jui; Harding, Scott A

    2016-01-01

    Transgenic Populus tremula x alba (717-1B4) plants with reduced expression of a tonoplast sucrose efflux transporter, PtaSUT4, exhibit reduced shoot growth compared to wild type (WT) under sustained mild drought. The present study was undertaken to determine whether SUT4-RNAi directly or indirectly altered poplar predisposition and/or response to changes in soil water availability. While sucrose and hexose levels were constitutively elevated in shoot organs, expression responses to drought were most altered in the root tips of SUT4-RNAi plants. Prior to any drought treatment, constitutively elevated transcript levels of abscisic acid biosynthetic genes and bark/vegetative storage proteins suggested altered metabolism in root tips of RNAi plants. Stronger drought-stimulation of stress-inducible genes encoding late-embryogenesis-abundant proteins in transgenic roots was consistent with increased vulnerability to soil drying. Transcript evidence suggested an RNAi effect on intercellular water trafficking by aquaporins in stem xylem during soil drying and recovery. Co-expression network analysis predicted altered integration of abscisic acid sensing/signaling with ethylene and jasmonate sensing/signaling in RNAi compared to WT roots. The overall conclusion is that steepened shoot-root sugar gradient in RNAi plants increased sensitivity of root tips to decreasing soil water availability. PMID:27641356

  19. Immunosenescence is associated with altered gene expression and epigenetic regulation in primary and secondary immune organs

    PubMed Central

    Sidler, Corinne; Wóycicki, Rafał; Ilnytskyy, Yaroslav; Metz, Gerlinde; Kovalchuk, Igor; Kovalchuk, Olga

    2013-01-01

    Deterioration of the immune system (immunosenescence) with age is associated with an increased susceptibility to infection, autoimmune disease and cancer, and reduced responsiveness to vaccination. Immunosenescence entails a reduced supply of naïve T cells from the thymus and increased specialization of peripheral T cell clones. Both thymic involution and peripheral T cell homeostasis are thought to involve cellular senescence. In order to analyze this at the molecular level, we studied gene expression profiles, epigenetic status, and genome stability in the thymus and spleen of 1-, 4-, and 18-month-old Long Evans rats. In the thymus, altered gene expression, DNA and histone H3K9 hypomethylation, increased genome instability, and apoptosis were observed in 18-month-old animals compared to 1- and 4-month-old animals. In the spleen, alterations in gene expression and epigenetic regulation occurred already by the age of 4 months compared to 1 month and persisted in 18-month-old compared to 1-month-old rats. In both organs, these changes were accompanied by the altered composition of resident T cell populations. Our study suggests that both senescence and apoptosis may be involved in altered organ function. PMID:24151501

  20. Restricted maternal nutrition alters myogenic regulatory factor expression in satellite cells of ovine offspring.

    PubMed

    Raja, J S; Hoffman, M L; Govoni, K E; Zinn, S A; Reed, S A

    2016-07-01

    Poor maternal nutrition inhibits muscle development and postnatal muscle growth. Satellite cells are myogenic precursor cells that contribute to postnatal muscle growth, and their activity can be evaluated by the expression of several transcription factors. Paired-box (Pax)7 is expressed in quiescent and active satellite cells. MyoD is expressed in activated and proliferating satellite cells and myogenin is expressed in terminally differentiating cells. Disruption in the expression pattern or timing of expression of myogenic regulatory factors negatively affects muscle development and growth. We hypothesized that poor maternal nutrition during gestation would alter the in vitro temporal expression of MyoD and myogenin in satellite cells from offspring at birth and 3 months of age. Ewes were fed 100% or 60% of NRC requirements from day 31±1.3 of gestation. Lambs from control-fed (CON) or restricted-fed (RES) ewes were euthanized within 24 h of birth (birth; n=5) or were fed a control diet until 3 months of age (n=5). Satellite cells isolated from the semitendinosus muscle were used for gene expression analysis or cultured for 24, 48 or 72 h and immunostained for Pax7, MyoD or myogenin. Fusion index was calculated from a subset of cells allowed to differentiate. Compared with CON, temporal expression of MyoD and myogenin was altered in cultured satellite cells isolated from RES lambs at birth. The percent of cells expressing MyoD was greater in RES than CON (P=0.03) after 24 h in culture. After 48 h of culture, there was a greater percent of cells expressing myogenin in RES compared with CON (P0.05). In satellite cells from RES lambs at 3 months of age, the percent of cells expressing MyoD and myogenin were greater than CON after 72 h in culture (P<0.05). Fusion index was reduced in RES lambs at 3 months of age compared with CON (P<0.001). Restricted nutrition during gestation alters the temporal expression of myogenic regulatory factors in satellite cells of the

  1. HC-Pro silencing suppressor significantly alters the gene expression profile in tobacco leaves and flowers

    PubMed Central

    2011-01-01

    Background RNA silencing is used in plants as a major defence mechanism against invasive nucleic acids, such as viruses. Accordingly, plant viruses have evolved to produce counter defensive RNA-silencing suppressors (RSSs). These factors interfere in various ways with the RNA silencing machinery in cells, and thereby disturb the microRNA (miRNA) mediated endogene regulation and induce developmental and morphological changes in plants. In this study we have explored these effects using previously characterized transgenic tobacco plants which constitutively express (under CaMV 35S promoter) the helper component-proteinase (HC-Pro) derived from a potyviral genome. The transcript levels of leaves and flowers of these plants were analysed using microarray techniques (Tobacco 4 × 44 k, Agilent). Results Over expression of HC-Pro RSS induced clear phenotypic changes both in growth rate and in leaf and flower morphology of the tobacco plants. The expression of 748 and 332 genes was significantly changed in the leaves and flowers, respectively, in the HC-Pro expressing transgenic plants. Interestingly, these transcriptome alterations in the HC-Pro expressing tobacco plants were similar as those previously detected in plants infected with ssRNA-viruses. Particularly, many defense-related and hormone-responsive genes (e.g. ethylene responsive transcription factor 1, ERF1) were differentially regulated in these plants. Also the expression of several stress-related genes, and genes related to cell wall modifications, protein processing, transcriptional regulation and photosynthesis were strongly altered. Moreover, genes regulating circadian cycle and flowering time were significantly altered, which may have induced a late flowering phenotype in HC-Pro expressing plants. The results also suggest that photosynthetic oxygen evolution, sugar metabolism and energy levels were significantly changed in these transgenic plants. Transcript levels of S-adenosyl-L-methionine (SAM) were

  2. Alteration of PHYA expression change circadian rhythms and timing of bud set in Populus.

    PubMed

    Kozarewa, Iwanka; Ibáñez, Cristian; Johansson, Mikael; Ogren, Erling; Mozley, David; Nylander, Eva; Chono, Makiko; Moritz, Thomas; Eriksson, Maria E

    2010-05-01

    In many temperate woody species, dormancy is induced by short photoperiods. Earlier studies have shown that the photoreceptor phytochrome A (phyA) promotes growth. Specifically, Populus plants that over-express the oat PHYA gene (oatPHYAox) show daylength-independent growth and do not become dormant. However, we show that oatPHYAox plants could be induced to set bud and become cold hardy by exposure to a shorter, non-24 h diurnal cycle that significantly alters the relative position between endogenous rhythms and perceived light/dark cycles. Furthermore, we describe studies in which the expression of endogenous Populus tremula x P. tremuloides PHYTOCHROME A (PttPHYA) was reduced in Populus trees by antisense inhibition. The antisense plants showed altered photoperiodic requirements, resulting in earlier growth cessation and bud formation in response to daylength shortening, an effect that was explained by an altered innate period that leads to phase changes of clock-associated genes such as PttCO2. Moreover, gene expression studies following far-red light pulses show a phyA-mediated repression of PttLHY1 and an induction of PttFKF1 and PttFT. We conclude that the level of PttPHYA expression strongly influences seasonally regulated growth in Populus and is central to co-ordination between internal clock-regulated rhythms and external light/dark cycles through its dual effect on the pace of clock rhythms and in light signaling.

  3. The expression of p73 is increased in lung cancer, independent of p53 gene alteration

    PubMed Central

    Tokuchi, Y; Hashimoto, T; Kobayashi, Y; Hayashi, M; Nishida, K; Hayashi, S; Imai, K; Nakachi, K; Ishikawa, Y; Nakagawa, K; Kawakami, Y; Tsuchiya, E

    1999-01-01

    p73 gene, a new p53 homologue, has been identified: it supposedly acts as tumour suppressor gene in neuroblastoma. To clarify whether p73 might be involved in lung carcinogenesis, we examined p73 expression in resected lung cancer and paired normal lung in 60 cases using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). We also examined p73 gene status in three representative cases using Southern blot, and p53 gene alteration in 49 cases using PCR-single-strand conformation polymorphism (PCR-SSCP) and direct sequence. In 87% of the cases (52/60) p73 expression in tumour was more than twice as high as that in paired normal lung tissues, and the difference between p73 expression in tumour and normal lung tissue was significant (P < 0.0001). However, Southern blot analysis revealed that none of the cases showed p73 gene amplification. Compared with clinicopathological characteristics, p73 expression correlates significantly with histological differences and age of patient, independently (P < 0.05). Concerning p53 gene status, 43% (21/49) showed p53 gene alteration, but there was no correlation between p73 overexpression and p53 gene alteration. Our results suggest that need for further functional analysis of the role of p73 in lung carcinogenesis. © 1999 Cancer Research Campaign PMID:10408409

  4. Altered Stra13 and Dec2 circadian gene expression in hypoxic cells

    SciTech Connect

    Guillaumond, Fabienne; Lacoche, Samuel; Dulong, Sandrine; Grechez-Cassiau, Aline; Filipski, Elisabeth; Li, Xiao-Mei; Levi, Francis; Berra, Edurne; Delaunay, Franck; Teboul, Michele

    2008-05-16

    The circadian system regulates rhythmically most of the mammalian physiology in synchrony with the environmental light/dark cycle. Alteration of circadian clock gene expression has been associated with tumour progression but the molecular links between the two mechanisms remain poorly defined. Here we show that Stra13 and Dec2, two circadian transcriptional regulators which play a crucial role in cell proliferation and apoptosis are overexpressed and no longer rhythmic in serum shocked fibroblasts treated with CoCl{sub 2,} a substitute of hypoxia. This effect is associated with a loss of circadian expression of the clock genes Rev-erb{alpha} and Bmal1, and the clock-controlled gene Dbp. Consistently, cotransfection assays demonstrate that STRA13 and DEC2 both antagonize CLOCK:BMAL1 dependent transactivation of the Rev-erb{alpha} and Dbp promoters. Using a transplantable osteosarcoma tumour model, we show that hypoxia is associated with altered circadian expression of Stra13, Dec2, Rev-erb{alpha}, Bmal1 and Dbp in vivo. These observations collectively support the notion that overexpression of Stra13 and Dec2 links hypoxia signalling to altered circadian clock gene expression.

  5. Altered expression of neuropeptides in FoxG1-null heterozygous mutant mice.

    PubMed

    Frullanti, Elisa; Amabile, Sonia; Lolli, Maria Grazia; Bartolini, Anna; Livide, Gabriella; Landucci, Elisa; Mari, Francesca; Vaccarino, Flora M; Ariani, Francesca; Massimino, Luca; Renieri, Alessandra; Meloni, Ilaria

    2016-02-01

    Foxg1 gene encodes for a transcription factor essential for telencephalon development in the embryonic mammalian forebrain. Its complete absence is embryonic lethal while Foxg1 heterozygous mice are viable but display microcephaly, altered hippocampal neurogenesis and behavioral and cognitive deficiencies. In order to evaluate the effects of Foxg1 alteration in adult brain, we performed expression profiling in total brains from Foxg1+/- heterozygous mutants and wild-type littermates. We identified statistically significant differences in expression levels for 466 transcripts (P<0.001), 29 of which showed a fold change ≥ 1.5. Among the differentially expressed genes was found a group of genes expressed in the basal ganglia and involved in the control of movements. A relevant (three to sevenfold changes) and statistically significant increase of expression, confirmed by qRT-PCR, was found in two highly correlated genes with expression restricted to the hypothalamus: Oxytocin (Oxt) and Arginine vasopressin (Avp). These neuropeptides have an important role in maternal and social behavior, and their alteration is associated with impaired social interaction and autistic behavior. In addition, Neuronatin (Nnat) levels appear significantly higher both in Foxg1+/- whole brain and in hippocampal neurons after silencing Foxg1, strongly suggesting that it is directly or indirectly repressed by Foxg1. During fetal and neonatal brain development, Nnat may regulate neuronal excitability, receptor trafficking and calcium-dependent signaling and, in the adult brain, it is predominantly expressed in parvalbumin-positive GABAergic interneurons. Overall, these results implicate the overexpression of a group of neuropeptides in the basal ganglia, hypothalamus, cortex and hippocampus in the pathogenesis FOXG1 behavioral impairments.

  6. MicroRNA-21 accelerates hepatocyte proliferation in vitro via PI3K/Akt signaling by targeting PTEN

    SciTech Connect

    Yan-nan, Bai; Zhao-yan, Yu; Li-xi, Luo; Jiang, Yi; Qing-jie, Xia

    2014-01-17

    Highlights: •miRNAs-expression patterns of primary hepatocytes under proliferative status. •miR-21 expression level peaked at 12 h after stimulated by EGF. •miR-21 drive rapid S phase entry of primary hepatocytes. •PI3K/Akt signaling was modulated via targeting PTEN by miR-21. -- Abstract: MicroRNAs (miRNAs) are involved in controlling hepatocyte proliferation during liver regeneration. In this study, we established the miRNAs-expression patterns of primary hepatocytes in vitro under stimulation of epidermal growth factor (EGF), and found that microRNA-21 (miR-21) was appreciably up-regulated and peaked at 12 h. In addition, we further presented evidences indicating that miR-21 promotes primary hepatocyte proliferation through in vitro transfecting with miR-21 mimics or inhibitor. We further demonstrated that phosphatidylinositol 3′-OH kinase (PI3K)/Akt signaling was altered accordingly, it is, by targeting phosphatase and tensin homologue deleted on chromosome 10, PI3K/Akt signaling is activated by miR-21 to accelerate hepatocyte rapid S-phase entry and proliferation in vitro.

  7. Altered Expression of Fibrosis Genes in Capsules of Failed Ahmed Glaucoma Valve Implants

    PubMed Central

    Mahale, Alka; Othman, Maha W.; Al Shahwan, Sami; Al Jadaan, Ibrahim; Owaydha, Ohood; Khan, Zahid; Edward, Deepak P.

    2015-01-01

    Purpose Ahmed glaucoma valve (AGV) implant is an aqueous shunt device used to control intraocular pressure in glaucoma. Implant failure results from impervious encapsulation of the shunt plate causing increased hydraulic resistance and raised intraocular pressure. We hypothesized that deregulation of fibrosis pathway contributes to capsular resistance. We tested this by studying fibrosis related gene expression in failed AGV implants. Methods Differential gene expression was examined in failed AGV capsules and compared to normal control tenon. Following total RNA extraction, 84 key genes in fibrosis pathway were examined by real-time PCR using RT2 Profiler PCR Array. Relative gene expression was calculated using ΔΔCt method. Gene specific TaqMan assays were used to validate select genes with ≥2 fold differential expression in the array expression profile. Results We observed differential expression in several genes in the fibrosis pathway. Almost half (39/84) of examined genes showed ≥2 fold differential expression in majority of capsules examined on the array. TaqMan assays for select genes including CCN2 (CTGF), THBS1, SERPINE1, THBS2, COL3A1, MMP3, and IL1A in an increased validation sample set showed significant changes in expression (p value from <0.001 to 0.022) at a high frequency in concurrence with our array results. Conclusions Pathway-focused analyses identified candidate genes with altered expression providing molecular evidence for deregulation of the fibrosis pathway in AGV failure. PMID:25879570

  8. Aged human muscle demonstrates an altered gene expression profile consistent with an impaired response to exercise.

    PubMed

    Jozsi, A C; Dupont-Versteegden, E E; Taylor-Jones, J M; Evans, W J; Trappe, T A; Campbell, W W; Peterson, C A

    2000-12-01

    The gene expression profile of skeletal muscle from healthy older (62-75 years old) compared with younger (20-34 years old) men demonstrated elevated expression of genes typical of a stress or damage response, and decreased expression of a gene encoding a DNA repair/cell cycle checkpoint protein. Although the expression of these genes was relatively unaffected by a single bout of resistance exercise in older men, acute exercise altered gene expression in younger men such that post-exercise gene expression in younger men was similar to baseline gene expression in older men. The lack of response of muscle from older subjects to resistance exercise was also apparent in the expression of the inflammatory response gene IL-1beta, which did not differ between the age groups at baseline, but increased within 24 h of the exercise bout only in younger subjects. Other genes with potentially important roles in the adaptation of muscle to exercise, specifically in the processes of angiogenesis and cell proliferation, showed a similar response to exercise in older compared with younger subjects. Only one gene encoding the multifunctional, early growth response transcription factor EGR-1, showed an opposite pattern of expression in response to exercise, acutely decreasing in younger and increasing in older subjects. These results may provide a molecular basis for the inherent variability in the response of muscle from older as compared with younger individuals to resistance training.

  9. Ectopic ERK Expression Induces Phenotypic Conversion of C10 Cells and Alters DNA Methyltransferase Expression

    SciTech Connect

    Sontag, Ryan L.; Weber, Thomas J.

    2012-05-04

    In some model systems constitutive extracellular signal regulated kinase (ERK) activation is sufficient to promote an oncogenic phenotype. Here we investigate whether constitutive ERK expression influences phenotypic conversion in murine C10 type II alveolar epithelial cells. C10 cells were stably transduced with an ERK1-green fluorescent protein (ERK1-GFP) chimera or empty vector and ectopic ERK expression was associated with the acquisition of soft agar focus-forming potential in late passage, but not early passage cells. Late passage ERK1-GFP cells exhibited a significant increase in the expression of DNA methyl transferases (DNMT1 and 3b) and a marked increase in sensitivity to 5-azacytidine (5-azaC)-mediated toxicity, relative to early passage ERK1-GFP cells and vector controls. The expression of xeroderma pigmentosum complementation group A (XPA) and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) were significantly increased in late passage cells, suggesting enhanced DNA damage recognition and repair activity which we interpret as a reflection of genomic instability. Phospho-ERK levels were dramatically decreased in late passage ERK1-GFP cells, relative to early passage and vector controls, and phospho-ERK levels were restored by treatment with sodium orthovanadate, indicating a role for phosphatase activity in this response. Collectively these observations suggest that ectopic ERK expression promotes phenotypic conversion of C10 cells that is associated with latent effects on epigenetic programming and phosphatase activities.

  10. Alteration of human hepatic drug transporter activity and expression by cigarette smoke condensate.

    PubMed

    Sayyed, Katia; Vee, Marc Le; Abdel-Razzak, Ziad; Jouan, Elodie; Stieger, Bruno; Denizot, Claire; Parmentier, Yannick; Fardel, Olivier

    2016-07-01

    Smoking is well-known to impair pharmacokinetics, through inducing expression of drug metabolizing enzymes. In the present study, we demonstrated that cigarette smoke condensate (CSC) also alters activity and expression of hepatic drug transporters, which are now recognized as major actors of hepatobiliary elimination of drugs. CSC thus directly inhibited activities of sinusoidal transporters such as OATP1B1, OATP1B3, OCT1 and NTCP as well as those of canalicular transporters like P-glycoprotein, MRP2, BCRP and MATE1, in hepatic transporters-overexpressing cells. CSC similarly counteracted constitutive OATP, NTCP and OCT1 activities in human highly-differentiated hepatic HepaRG cells. In parallel, CSC induced expression of BCRP at both mRNA and protein level in HepaRG cells, whereas it concomitantly repressed mRNA expression of various transporters, including OATP1B1, OATP2B1, OAT2, NTCP, OCT1 and BSEP, and enhanced that of MRP4. Such changes in transporter gene expression were found to be highly correlated to those caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin, a reference activator of the aryl hydrocarbon receptor (AhR) pathway, and were counteracted, for some of them, by siRNA-mediated AhR silencing. This suggests that CSC alters hepatic drug transporter levels via activation of the AhR cascade. Importantly, drug transporter expression regulations as well as some transporter activity inhibitions occurred for a range of CSC concentrations similar to those required for inducing drug metabolizing enzymes and may therefore be hypothesized to be relevant for smokers. Taken together, these data established human hepatic transporters as targets of cigarette smoke, which could contribute to known alteration of pharmacokinetics and some liver adverse effects caused by smoking. PMID:27450509

  11. Altered Gene Expression in Schizophrenia: Findings from Transcriptional Signatures in Fibroblasts and Blood

    PubMed Central

    Cattane, Nadia; Minelli, Alessandra; Milanesi, Elena; Maj, Carlo; Bignotti, Stefano; Bortolomasi, Marco; Chiavetto, Luisella Bocchio; Gennarelli, Massimo

    2015-01-01

    Background Whole-genome expression studies in the peripheral tissues of patients affected by schizophrenia (SCZ) can provide new insight into the molecular basis of the disorder and innovative biomarkers that may be of great utility in clinical practice. Recent evidence suggests that skin fibroblasts could represent a non-neural peripheral model useful for investigating molecular alterations in psychiatric disorders. Methods A microarray expression study was conducted comparing skin fibroblast transcriptomic profiles from 20 SCZ patients and 20 controls. All genes strongly differentially expressed were validated by real-time quantitative PCR (RT-qPCR) in fibroblasts and analyzed in a sample of peripheral blood cell (PBC) RNA from patients (n = 25) and controls (n = 22). To evaluate the specificity for SCZ, alterations in gene expression were tested in additional samples of fibroblasts and PBCs RNA from Major Depressive Disorder (MDD) (n = 16; n = 21, respectively) and Bipolar Disorder (BD) patients (n = 15; n = 20, respectively). Results Six genes (JUN, HIST2H2BE, FOSB, FOS, EGR1, TCF4) were significantly upregulated in SCZ compared to control fibroblasts. In blood, an increase in expression levels was confirmed only for EGR1, whereas JUN was downregulated; no significant differences were observed for the other genes. EGR1 upregulation was specific for SCZ compared to MDD and BD. Conclusions Our study reports the upregulation of JUN, HIST2H2BE, FOSB, FOS, EGR1 and TCF4 in the fibroblasts of SCZ patients. A significant alteration in EGR1 expression is also present in SCZ PBCs compared to controls and to MDD and BD patients, suggesting that this gene could be a specific biomarker helpful in the differential diagnosis of major psychoses. PMID:25658856

  12. Chronic mild stress alters circadian expressions of molecular clock genes in the liver.

    PubMed

    Takahashi, Kei; Yamada, Tetsuya; Tsukita, Sohei; Kaneko, Keizo; Shirai, Yuta; Munakata, Yuichiro; Ishigaki, Yasushi; Imai, Junta; Uno, Kenji; Hasegawa, Yutaka; Sawada, Shojiro; Oka, Yoshitomo; Katagiri, Hideki

    2013-02-01

    Chronic stress is well known to affect metabolic regulation. However, molecular mechanisms interconnecting stress response systems and metabolic regulations have yet to be elucidated. Various physiological processes, including glucose/lipid metabolism, are regulated by the circadian clock, and core clock gene dysregulation reportedly leads to metabolic disorders. Glucocorticoids, acting as end-effectors of the hypothalamus-pituitary-adrenal (HPA) axis, entrain the circadian rhythms of peripheral organs, including the liver, by phase-shifting core clock gene expressions. Therefore, we examined whether chronic stress affects circadian expressions of core clock genes and metabolism-related genes in the liver using the chronic mild stress (CMS) procedure. In BALB/c mice, CMS elevated and phase-shifted serum corticosterone levels, indicating overactivation of the HPA axis. The rhythmic expressions of core clock genes, e.g., Clock, Npas2, Bmal1, Per1, and Cry1, were altered in the liver while being completely preserved in the hypothalamic suprachiasmatic nuculeus (SCN), suggesting that the SCN is not involved in alterations in hepatic core clock gene expressions. In addition, circadian patterns of glucose and lipid metabolism-related genes, e.g., peroxisome proliferator activated receptor (Ppar) α, Pparγ-1, Pparγ-coactivator-1α, and phosphoenolepyruvate carboxykinase, were also disturbed by CMS. In contrast, in C57BL/6 mice, the same CMS procedure altered neither serum corticosterone levels nor rhythmic expressions of hepatic core clock genes and metabolism-related genes. Thus, chronic stress can interfere with the circadian expressions of both core clock genes and metabolism-related genes in the liver possibly involving HPA axis overactivation. This mechanism might contribute to metabolic disorders in stressful modern societies.

  13. Image Defocus and Altered Retinal Gene Expression in Chick: Clues to the Pathogenesis of Ametropia

    PubMed Central

    McGlinn, Alice M.; Baldwin, Donald A.; Tobias, John W.; Iuvone, P. Michael; Khurana, Tejvir S.

    2011-01-01

    Purpose. Because of the retina's role in refractive development, this study was conducted to analyze the retinal transcriptome in chicks wearing a spectacle lens, a well-established means of inducing refractive errors, to identify gene expression alterations and to develop novel mechanistic hypotheses about refractive development. Methods. One-week-old white Leghorn chicks wore a unilateral spectacle lens of +15 or −15 D for 6 hours or 3 days. With total RNA from the retina/(retinal pigment epithelium, RPE), chicken gene microarrays were used to compare gene expression levels between lens-wearing and contralateral control eyes (n = 6 chicks for each condition). Normalized microarray signal intensities were evaluated by analysis of variance, using a false discovery rate of <10% as the statistical criterion. Selected differentially expressed genes were validated by qPCR. Results. Very few retina/RPE transcripts were differentially expressed after plus lens wear. In contrast, approximately 1300 transcripts were differentially expressed under each of the minus lens conditions, with minimal overlap. For each condition, low fold-changes typified the altered transcriptome. Differentially regulated genes under the minus lens conditions included many potentially informative signaling molecules and genes whose protein products have roles in intrinsic retinal circadian rhythms. Conclusions. Plus or minus lens wear induce markedly different, not opposite, alterations in retina/RPE gene expression. The initial retinal responses to defocus are quite different from those when the eye growth patterns are well established, suggesting that different mechanisms govern the initiation and persistence or progression of refractive errors. The gene lists identify promising signaling candidates and regulatory pathways for future study, including a potential role for circadian rhythms in refractive development. PMID:21642623

  14. Gene expression patterns underlying parasite-induced alterations in host behaviour and life history.

    PubMed

    Feldmeyer, Barbara; Mazur, Johanna; Beros, Sara; Lerp, Hannes; Binder, Harald; Foitzik, Susanne

    2016-01-01

    Many parasites manipulate their hosts' phenotype. In particular, parasites with complex life cycles take control of their intermediate hosts' behaviour and life history to increase transmission to their definitive host. The proximate mechanisms underlying these parasite-induced alterations are poorly understood. The cestode Anomotaenia brevis affects the behaviour, life history and morphology of parasitized Temnothorax nylanderi ants and indirectly of their unparasitized nestmates. To gain insights on how parasites alter host phenotypes, we contrast brain gene expression patterns of T. nylanderi workers parasitized with the cestode, their unparasitized nestmates and unparasitized workers from unparasitized colonies. Over 400 differentially expressed genes between the three groups were identified, with most uniquely expressed genes detected in parasitized workers. Among these are genes that can be linked to the increased lifespan of parasitized workers. Furthermore, many muscle (functionality) genes are downregulated in these workers, potentially causing the observed muscular deformations and their inactive behaviour. Alterations in lifespan and activity could be adaptive for the parasite by increasing the likelihood that infected workers residing in acorns are eaten by their definitive host, a woodpecker. Our transcriptome analysis reveals numerous gene expression changes in parasitized workers and their uninfected nestmates and indicates possible routes of parasite manipulation. Although causality still needs to be established, parasite-induced alterations in lifespan and host behaviour appear to be partly explained by morphological muscle atrophy instead of central nervous system interference, which is often the core of behavioural regulation. Results of this study will shed light upon the molecular basis of antagonistic species interactions.

  15. Gene expression patterns underlying parasite-induced alterations in host behaviour and life history.

    PubMed

    Feldmeyer, Barbara; Mazur, Johanna; Beros, Sara; Lerp, Hannes; Binder, Harald; Foitzik, Susanne

    2016-01-01

    Many parasites manipulate their hosts' phenotype. In particular, parasites with complex life cycles take control of their intermediate hosts' behaviour and life history to increase transmission to their definitive host. The proximate mechanisms underlying these parasite-induced alterations are poorly understood. The cestode Anomotaenia brevis affects the behaviour, life history and morphology of parasitized Temnothorax nylanderi ants and indirectly of their unparasitized nestmates. To gain insights on how parasites alter host phenotypes, we contrast brain gene expression patterns of T. nylanderi workers parasitized with the cestode, their unparasitized nestmates and unparasitized workers from unparasitized colonies. Over 400 differentially expressed genes between the three groups were identified, with most uniquely expressed genes detected in parasitized workers. Among these are genes that can be linked to the increased lifespan of parasitized workers. Furthermore, many muscle (functionality) genes are downregulated in these workers, potentially causing the observed muscular deformations and their inactive behaviour. Alterations in lifespan and activity could be adaptive for the parasite by increasing the likelihood that infected workers residing in acorns are eaten by their definitive host, a woodpecker. Our transcriptome analysis reveals numerous gene expression changes in parasitized workers and their uninfected nestmates and indicates possible routes of parasite manipulation. Although causality still needs to be established, parasite-induced alterations in lifespan and host behaviour appear to be partly explained by morphological muscle atrophy instead of central nervous system interference, which is often the core of behavioural regulation. Results of this study will shed light upon the molecular basis of antagonistic species interactions. PMID:26615010

  16. Oxidative Stress Alters miRNA and Gene Expression Profiles in Villous First Trimester Trophoblasts

    PubMed Central

    Cross, Courtney E.; Tolba, Mai F.; Rondelli, Catherine M.; Xu, Meixiang; Abdel-Rahman, Sherif Z.

    2015-01-01

    The relationship between oxidative stress and miRNA changes in placenta as a potential mechanism involved in preeclampsia (PE) is not fully elucidated. We investigated the impact of oxidative stress on miRNAs and mRNA expression profiles of genes associated with PE in villous 3A first trimester trophoblast cells exposed to H2O2 at 12 different concentrations (0-1 mM) for 0.5, 4, 24, and 48 h. Cytotoxicity, determined using the SRB assay, was used to calculate the IC50 of H2O2. RNA was extracted after 4 h exposure to H2O2 for miRNA and gene expression profiling. H2O2 exerted a concentration- and time-dependent cytotoxicity on 3A trophoblast cells. Short-term exposure of 3A cells to low concentration of H2O2 (5% of IC50) significantly altered miRNA profile as evidenced by significant changes in 195 out of 595 evaluable miRNAs. Tool for annotations of microRNAs (TAM) analysis indicated that these altered miRNAs fall into 43 clusters and 34 families, with 41 functions identified. Exposure to H2O2 altered mRNA expression of 22 out of 84 key genes involved in dysregulation of placental development. In conclusion, short-term exposure of villous first trimester trophoblasts to low concentrations of H2O2 significantly alters miRNA profile and expression of genes implicated in placental development. PMID:26339600

  17. In vitro - in vivo correlation of gene expression alterations induced by liver carcinogens.

    PubMed

    Heise, T; Schug, M; Storm, D; Ellinger-Ziegelbauer, H; Ahr, H J; Hellwig, B; Rahnenfuhrer, J; Ghallab, A; Guenther, G; Sisnaiske, J; Reif, R; Godoy, P; Mielke, H; Gundert-Remy, U; Lampen, A; Oberemm, A; Hengstler, J G

    2012-01-01

    Although cultivated hepatocytes are widely used in the studies of drug metabolism, their application in toxicogenomics is considered as problematic, because previous studies have reported only little overlap between chemically induced gene expression alterations in liver in vivo and in cultivated hepatocytes. Here, we identified 22 genes that were altered in livers of rats after oral administration of the liver carcinogens aflatoxin B1 (AB1), 2-nitrofluorene (2-NF), methapyrilene (MP) or piperonyl-butoxide (PBO). The functions of the 22 genes have been classified into two groups. Genes related to stress response, DNA repair or metabolism and genes associated with cell proliferation, respectively. Next, rat hepatocyte sandwich cultures were exposed to AB1, 2-NF, MP or PBO for 24h and expression of the above mentioned genes was determined by RT-qPCR. Significant correlations between the degree of gene expression alterations in vivo and in vitro were obtained for the stress, DNA repair and metabolism associated genes at concentrations covering a range from cytotoxic concentrations to non-toxic/in vivo relevant concentrations. In contrast to the stress associated genes, no significant in vivo/in vitro correlation was obtained for the genes associated with cell proliferation. To understand the reason of this discrepancy, we compared replacement proliferation in vivo and in vitro. While hepatocytes in vivo, killed after administration of hepatotoxic compounds, are rapidly replaced by proliferating surviving cells, in vitro no replacement proliferation as evidenced by BrdU incorporation was observed after washing out hepatotoxic concentrations of MP. In conclusion, there is a good correlation between gene expression alterations induced by liver carcinogens in vivo and in cultivated hepatocytes. However, it should be considered that cultivated primary hepatocytes do not show replacement proliferation explaining the in vivo/in vitro discrepancy concerning proliferation

  18. Altered Expression of Bone Morphogenetic Protein Accessory Proteins in Murine and Human Pulmonary Fibrosis.

    PubMed

    Murphy, Noelle; Gaynor, Katherine U; Rowan, Simon C; Walsh, Sinead M; Fabre, Aurelie; Boylan, John; Keane, Michael P; McLoughlin, Paul

    2016-03-01

    Idiopathic pulmonary fibrosis is a chronic, progressive fibrotic disease with a poor prognosis. The balance between transforming growth factor β1 and bone morphogenetic protein (BMP) signaling plays an important role in tissue homeostasis, and alterations can result in pulmonary fibrosis. We hypothesized that multiple BMP accessory proteins may be responsible for maintaining this balance in the lung. Using the bleomycin mouse model for fibrosis, we examined an array of BMP accessory proteins for changes in mRNA expression. We report significant increases in mRNA expression of gremlin 1, noggin, follistatin, and follistatin-like 1 (Fstl1), and significant decreases in mRNA expression of chordin, kielin/chordin-like protein, nephroblastoma overexpressed gene, and BMP and activin membrane-bound inhibitor (BAMBI). Protein expression studies demonstrated increased levels of noggin, BAMBI, and FSTL1 in the lungs of bleomycin-treated mice and in the lungs of idiopathic pulmonary fibrosis patients. Furthermore, we demonstrated that transforming growth factor β stimulation resulted in increased expression of noggin, BAMBI, and FSTL1 in human small airway epithelial cells. These results provide the first evidence that multiple BMP accessory proteins are altered in fibrosis and may play a role in promoting fibrotic injury.

  19. Prickle1 stunts limb growth through alteration of cell polarity and gene expression

    PubMed Central

    Yang, Tian; Bassuk, Alexander G.; Fritzsch, Bernd

    2014-01-01

    Background Wnt/PCP signaling plays a critical role in multiple developmental processes, including limb development. Wnt5a, a ligand of the PCP pathway, signals through the Ror2/Vangl2 or the Vangl2/Ryk complex to regulate limb development along the proximal-distal axis in mice. Based on the interaction between Van Gogh and Prickle in Drosophila, we hypothesized the vertebrate Prickle1 have similar function as Vangl2 in limb development. Results We show Prickle1 is expressed in the skeletal condensates that will differentiate into chondrocytes and later form bones. Disrupted Prickle1 function in Prickle1C251X/C251X mouse mutants alters expression of genes such as Bmp4, Fgf8, Vangl2 and Wnt5a. These expression changes correlate with shorter and wider bones in the limbs and loss of one phalangeal segment in digits 2-5 of Prickle1C251X mutants. These growth defects along the proximal-distal axis are also associated with increased cell death in the growing digit tip, reduced cell death in the interdigital membrane and disrupted chondrocyte polarity. Conclusions We suggest Prickle1 is part of the Wnt5a/PCP signaling, regulating cell polarity and affecting expression of multiple factors to stunt limb growth through altered patterns of gene expression, including the PCP genes Wnt5a and Vangl2. PMID:23913870

  20. Microarray analysis reveals altered circulating microRNA expression in mice infected with Coxsackievirus B3

    PubMed Central

    Sun, Chaoyu; Tong, Lei; Zhao, Wenran; Wang, Yan; Meng, Yuan; Lin, Lexun; Liu, Bingchen; Zhai, Yujia; Zhong, Zhaohua; Li, Xueqi

    2016-01-01

    Coxsackievirus B3 (CVB3) is a common causative agent in the development of inflammatory cardiomyopathy. However, whether the expression of peripheral blood microRNAs (miRNAs) is altered in this process is unknown. The present study investigated changes to miRNA expression in the peripheral blood of CVB3-infected mice. Utilizing miRNA microarray technology, differential miRNA expression was examined between normal and CVB3-infected mice. The present results suggest that specific miRNAs were differentially expressed in the peripheral blood of mice infected with CVB3, varying with infection duration. Using miRNA microarray analysis, a total of 96 and 89 differentially expressed miRNAs were identified in the peripheral blood of mice infected with CVB3 for 3 and 6 days, respectively. Quantitative polymerase chain reaction was used to validate differentially expressed miRNAs, revealing a consistency of these results with the miRNA microarray analysis results. The biological functions of the differentially expressed miRNAs were then predicted by bioinformatics analysis. The potential biological roles of differentially expressed miRNAs included hypertrophic cardiomyopathy, dilated cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy. These results may provide important insights into the mechanisms responsible for the progression of CVB3 infection. PMID:27698715

  1. Microarray analysis reveals altered circulating microRNA expression in mice infected with Coxsackievirus B3

    PubMed Central

    Sun, Chaoyu; Tong, Lei; Zhao, Wenran; Wang, Yan; Meng, Yuan; Lin, Lexun; Liu, Bingchen; Zhai, Yujia; Zhong, Zhaohua; Li, Xueqi

    2016-01-01

    Coxsackievirus B3 (CVB3) is a common causative agent in the development of inflammatory cardiomyopathy. However, whether the expression of peripheral blood microRNAs (miRNAs) is altered in this process is unknown. The present study investigated changes to miRNA expression in the peripheral blood of CVB3-infected mice. Utilizing miRNA microarray technology, differential miRNA expression was examined between normal and CVB3-infected mice. The present results suggest that specific miRNAs were differentially expressed in the peripheral blood of mice infected with CVB3, varying with infection duration. Using miRNA microarray analysis, a total of 96 and 89 differentially expressed miRNAs were identified in the peripheral blood of mice infected with CVB3 for 3 and 6 days, respectively. Quantitative polymerase chain reaction was used to validate differentially expressed miRNAs, revealing a consistency of these results with the miRNA microarray analysis results. The biological functions of the differentially expressed miRNAs were then predicted by bioinformatics analysis. The potential biological roles of differentially expressed miRNAs included hypertrophic cardiomyopathy, dilated cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy. These results may provide important insights into the mechanisms responsible for the progression of CVB3 infection.

  2. Warming Alters Expressions of Microbial Functional Genes Important to Ecosystem Functioning

    PubMed Central

    Xue, Kai; Xie, Jianping; Zhou, Aifen; Liu, Feifei; Li, Dejun; Wu, Liyou; Deng, Ye; He, Zhili; Van Nostrand, Joy D.; Luo, Yiqi; Zhou, Jizhong

    2016-01-01

    Soil microbial communities play critical roles in ecosystem functioning and are likely altered by climate warming. However, so far, little is known about effects of warming on microbial functional gene expressions. Here, we applied functional gene array (GeoChip 3.0) to analyze cDNA reversely transcribed from total RNA to assess expressed functional genes in active soil microbial communities after nine years of experimental warming in a tallgrass prairie. Our results showed that warming significantly altered the community wide gene expressions. Specifically, expressed genes for degrading more recalcitrant carbon were stimulated by warming, likely linked to the plant community shift toward more C4 species under warming and to decrease the long-term soil carbon stability. In addition, warming changed expressed genes in labile C degradation and N cycling in different directions (increase and decrease), possibly reflecting the dynamics of labile C and available N pools during sampling. However, the average abundances of expressed genes in phosphorus and sulfur cycling were all increased by warming, implying a stable trend of accelerated P and S processes which might be a mechanism to sustain higher plant growth. Furthermore, the expressed gene composition was closely related to both dynamic (e.g., soil moisture) and stable environmental attributes (e.g., C4 leaf C or N content), indicating that RNA analyses could also capture certain stable trends in the long-term treatment. Overall, this study revealed the importance of elucidating functional gene expressions of soil microbial community in enhancing our understanding of ecosystem responses to warming. PMID:27199978

  3. Altered tryptophan hydroxylase 2 expression in enteric serotonergic nerves in Hirschsprung’s-associated enterocolitis

    PubMed Central

    Coyle, David; Murphy, Justin M; Doyle, Brian; O’Donnell, Anne Marie; Gillick, John; Puri, Prem

    2016-01-01

    AIM: To determine if expression of colonic tryptophan hydroxylase-2 (TPH2), a surrogate marker of neuronal 5-hydroxytryptamine, is altered in Hirschsprung’s-associated enterocolitis. METHODS: Entire resected colonic specimens were collected at the time of pull-through operation in children with Hirschsprung’s disease (HSCR, n = 12). Five of these patients had a history of pre-operative Hirschsprung’s-associated enterocolitis (HAEC). Controls were collected at colostomy closure in children with anorectal malformation (n = 10). The distribution of expression of TPH2 was evaluated using immunofluorescence and confocal microscopy. Protein expression of TPH2 was quantified using western blot analysis in the deep smooth muscle layers. RESULTS: TPH2 was co-expressed in nitrergic and cholinergic ganglia in the myenteric and submucosal plexuses in ganglionic colon in HSCR and healthy controls. Co-expression was also seen in submucosal interstitial cells of Cajal and PDGFRα+ cells. The density of TPH2 immuno-positive fibers decreased incrementally from ganglionic bowel to transition zone bowel to aganglionic bowel in the myenteric plexus. Expression of TPH2 was reduced in ganglionic bowel in those affected by pre-operative HAEC compared to those without HAEC and healthy controls. However, expression of TPH2 was similar or high compared to controls in the colons of children who had undergone diverting colostomy for medically refractory HAEC. CONCLUSION: Altered TPH2 expression in colonic serotonergic nerves of patients with HSCR complicated by HAEC may contribute to intestinal secretory and motor disturbances, including recurrent HAEC. PMID:27217698

  4. Warming Alters Expressions of Microbial Functional Genes Important to Ecosystem Functioning.

    PubMed

    Xue, Kai; Xie, Jianping; Zhou, Aifen; Liu, Feifei; Li, Dejun; Wu, Liyou; Deng, Ye; He, Zhili; Van Nostrand, Joy D; Luo, Yiqi; Zhou, Jizhong

    2016-01-01

    Soil microbial communities play critical roles in ecosystem functioning and are likely altered by climate warming. However, so far, little is known about effects of warming on microbial functional gene expressions. Here, we applied functional gene array (GeoChip 3.0) to analyze cDNA reversely transcribed from total RNA to assess expressed functional genes in active soil microbial communities after nine years of experimental warming in a tallgrass prairie. Our results showed that warming significantly altered the community wide gene expressions. Specifically, expressed genes for degrading more recalcitrant carbon were stimulated by warming, likely linked to the plant community shift toward more C4 species under warming and to decrease the long-term soil carbon stability. In addition, warming changed expressed genes in labile C degradation and N cycling in different directions (increase and decrease), possibly reflecting the dynamics of labile C and available N pools during sampling. However, the average abundances of expressed genes in phosphorus and sulfur cycling were all increased by warming, implying a stable trend of accelerated P and S processes which might be a mechanism to sustain higher plant growth. Furthermore, the expressed gene composition was closely related to both dynamic (e.g., soil moisture) and stable environmental attributes (e.g., C4 leaf C or N content), indicating that RNA analyses could also capture certain stable trends in the long-term treatment. Overall, this study revealed the importance of elucidating functional gene expressions of soil microbial community in enhancing our understanding of ecosystem responses to warming.

  5. Transforming growth factor-beta1 upregulation triggers pulmonary artery smooth muscle cell proliferation and apoptosis imbalance in rats with hypoxic pulmonary hypertension via the PTEN/AKT pathways.

    PubMed

    Liu, Yun; Cao, Yonggang; Sun, Shuyang; Zhu, Jinquan; Gao, Shan; Pang, Jie; Zhu, Daling; Sun, Zengxian

    2016-08-01

    Transforming growth factor-beta1 (TGFβ1) and Phosphatase and Tensin homolog deleted on chromosome ten (PTEN) are involved in the regulation of proliferation, differentiation, migration and apoptosis of various cell types. In previous studies, we have shown that TGFβ1 and PTEN play an important role in the progression of pulmonary vascular remodeling induced by pulmonary artery smooth muscle cells (PASMCs). However, the mechanisms involved in the activation of PASMCs between TGFβ1 and PTEN pathways remain unknown. We found that pulmonary vascular walls in hypoxic pulmonary arterial hypertension (PAH) rats were thicker than the vessels from normal rats in vivo. Substantially higher levels of TGFβ1 and significant loss of PTEN expression were observed in the lungs of PAH rats when compared with normoxia. Meanwhile, AKT, a downstream proliferative signaling protein of the PTEN antagonist PI3K, was markedly activated in the lungs of PAH rats. In vitro studies using PASMCs showed that TGFβ1 increased cell proliferation in PTEN-dependent manner. Moreover, we found that TGFβ1 enhanced cell survival, up-regulated the expression of Bcl-2 and procaspase-3, decreased the number of TUNEL-positive cells and caspase-3 expression in PASMCs under serum-deprived (SD) condition via PI3K/AKT pathway. The results further establish that TGFβ1 promoted PAH by decreasing PTEN expression and increasing PI3K/AKT activation in the lung. In conclusion, TGFβ1 mediated PTEN inactivation and resistance to apoptosis seems to be key mediators of lung vascular remodeling associated with PAH. These findings further clarify molecular mechanisms that support targeting PTEN/AKT signaling pathway to attenuate pathogenic derangements in PAH.

  6. The PTEN-regulating microRNA miR-26a is amplified in high-grade glioma and facilitates gliomagenesis in vivo

    PubMed Central

    Huse, Jason T.; Brennan, Cameron; Hambardzumyan, Dolores; Wee, Boyoung; Pena, John; Rouhanifard, Sara H.; Sohn-Lee, Cherin; le Sage, Carlos; Agami, Reuven; Tuschl, Thomas; Holland, Eric C.

    2009-01-01

    Activated oncogenic signaling is central to the development of nearly all forms of cancer, including the most common class of primary brain tumor, glioma. Research over the last two decades has revealed the particular importance of the Akt pathway, and its molecular antagonist PTEN (phosphatase and tensin homolog), in the process of gliomagenesis. Recent studies have also demonstrated that microRNAs (miRNAs) may be responsible for the modulation of cancer-implicated genes in tumors. Here we report the identification miR-26a as a direct regulator of PTEN expression. We also show that miR-26a is frequently amplified at the DNA level in human glioma, most often in association with monoallelic PTEN loss. Finally, we demonstrate that miR-26a-mediated PTEN repression in a murine glioma model both enhances de novo tumor formation and precludes loss of heterozygosity and the PTEN locus. Our results document a new epigenetic mechanism for PTEN regulation in glioma and further highlight dysregulation of Akt signaling as crucial to the development of these tumors. PMID:19487573

  7. PRENATAL ALCOHOL EXPOSURE ALTERS STEADY-STATE AND ACTIVATED GENE EXPRESSION IN THE ADULT RAT BRAIN

    PubMed Central

    Stepien, Katarzyna A.; Lussier, Alexandre A.; Neumann, Sarah M.; Pavlidis, Paul; Kobor, Michael S.; Weinberg, Joanne

    2016-01-01

    Background Prenatal alcohol exposure (PAE) is associated with alterations in numerous physiological systems, including the stress and immune systems . We have previously shown that PAE increases the course and severity of arthritis in an adjuvant-induced arthritis (AA) model. While the molecular mechanisms underlying these effects are not fully known, changes in neural gene expression are emerging as important factors in the etiology of PAE effects. As the prefrontal cortex (PFC) and hippocampus (HPC) play key roles in neuroimmune function, PAE-induced alterations to their transcriptome may underlie abnormal steady-state functions and responses to immune challenge. The current study examined brains from adult PAE and control females from our recent AA study to determine whether PAE causes long-term alterations in gene expression and whether these mediate the altered severity and course of arthritis in PAE females Methods Adult females from PAE, pair-fed [PF], and ad libitum-fed control [C]) groups were injected with either saline or complete Freund’s adjuvant. Animals were terminated at the peak of inflammation or during resolution (days 16 and 39 post-injection, respectively); cohorts of saline-injected PAE, PF and C females were terminated in parallel. Gene expression was analyzed in the PFC and HPC using whole genome mRNA expression microarrays. Results Significant changes in gene expression in both the PFC and HPC were found in PAE compared to controls in response to ethanol exposure alone (saline-injected females), including genes involved in neurodevelopment, apoptosis, and energy metabolism. Moreover, in response to inflammation (adjuvant-injected females), PAE animals showed unique expression patterns, while failing to exhibit the activation of genes and regulators involved in the immune response observed in control and pair-fed animals. Conclusions These results support the hypothesis that PAE affects neuroimmune function at the level of gene expression

  8. Comparison of gene expression profiles altered by comfrey and riddelliine in rat liver

    PubMed Central

    Guo, Lei; Mei, Nan; Dial, Stacey; Fuscoe, James; Chen, Tao

    2007-01-01

    Background Comfrey (Symphytum officinale) is a perennial plant and has been consumed by humans as a vegetable, a tea and an herbal medicine for more than 2000 years. It, however, is hepatotoxic and carcinogenic in experimental animals and hepatotoxic in humans. Pyrrolizidine alkaloids (PAs) exist in many plants and many of them cause liver toxicity and/or cancer in humans and experimental animals. In our previous study, we found that the mutagenicity of comfrey was associated with the PAs contained in the plant. Therefore, we suggest that carcinogenicity of comfrey result from those PAs. To confirm our hypothesis, we compared the expression of genes and processes of biological functions that were altered by comfrey (mixture of the plant with PAs) and riddelliine (a prototype of carcinogenic PA) in rat liver for carcinogenesis in this study. Results Groups of 6 Big Blue Fisher 344 rats were treated with riddelliine at 1 mg/kg body weight by gavage five times a week for 12 weeks or fed a diet containing 8% comfrey root for 12 weeks. Animals were sacrificed one day after the last treatment and the livers were isolated for gene expression analysis. The gene expressions were investigated using Applied Biosystems Rat Whole Genome Survey Microarrays and the biological functions were analyzed with Ingenuity Analysis Pathway software. Although there were large differences between the significant genes and between the biological processes that were altered by comfrey and riddelliine, there were a number of common genes and function processes that were related to carcinogenesis. There was a strong correlation between the two treatments for fold-change alterations in expression of drug metabolizing and cancer-related genes. Conclusion Our results suggest that the carcinogenesis-related gene expression patterns resulting from the treatments of comfrey and riddelliine are very similar, and PAs contained in comfrey are the main active components responsible for carcinogenicity of

  9. A functional dissection of PTEN N-terminus: implications in PTEN subcellular targeting and tumor suppressor activity.

    PubMed

    Gil, Anabel; Rodríguez-Escudero, Isabel; Stumpf, Miriam; Molina, María; Cid, Víctor J; Pulido, Rafael

    2015-01-01

    Spatial regulation of the tumor suppressor PTEN is exerted through alternative plasma membrane, cytoplasmic, and nuclear subcellular locations. The N-terminal region of PTEN is important for the control of PTEN subcellular localization and function. It contains both an active nuclear localization signal (NLS) and an overlapping PIP2-binding motif (PBM) involved in plasma membrane targeting. We report a comprehensive mutational and functional analysis of the PTEN N-terminus, including a panel of tumor-related mutations at this region. Nuclear/cytoplasmic partitioning in mammalian cells and PIP3 phosphatase assays in reconstituted S. cerevisiae defined categories of PTEN N-terminal mutations with distinct PIP3 phosphatase and nuclear accumulation properties. Noticeably, most tumor-related mutations that lost PIP3 phosphatase activity also displayed impaired nuclear localization. Cell proliferation and soft-agar colony formation analysis in mammalian cells of mutations with distinctive nuclear accumulation and catalytic activity patterns suggested a contribution of both properties to PTEN tumor suppressor activity. Our functional dissection of the PTEN N-terminus provides the basis for a systematic analysis of tumor-related and experimentally engineered PTEN mutations.

  10. A Functional Dissection of PTEN N-Terminus: Implications in PTEN Subcellular Targeting and Tumor Suppressor Activity

    PubMed Central

    Gil, Anabel; Rodríguez-Escudero, Isabel; Stumpf, Miriam; Molina, María; Cid, Víctor J.; Pulido, Rafael

    2015-01-01

    Spatial regulation of the tumor suppressor PTEN is exerted through alternative plasma membrane, cytoplasmic, and nuclear subcellular locations. The N-terminal region of PTEN is important for the control of PTEN subcellular localization and function. It contains both an active nuclear localization signal (NLS) and an overlapping PIP2-binding motif (PBM) involved in plasma membrane targeting. We report a comprehensive mutational and functional analysis of the PTEN N-terminus, including a panel of tumor-related mutations at this region. Nuclear/cytoplasmic partitioning in mammalian cells and PIP3 phosphatase assays in reconstituted S. cerevisiae defined categories of PTEN N-terminal mutations with distinct PIP3 phosphatase and nuclear accumulation properties. Noticeably, most tumor-related mutations that lost PIP3 phosphatase activity also displayed impaired nuclear localization. Cell proliferation and soft-agar colony formation analysis in mammalian cells of mutations with distinctive nuclear accumulation and catalytic activity patterns suggested a contribution of both properties to PTEN tumor suppressor activity. Our functional dissection of the PTEN N-terminus provides the basis for a systematic analysis of tumor-related and experimentally engineered PTEN mutations. PMID:25875300

  11. Heparanase Overexpression Reduces Hepcidin Expression, Affects Iron Homeostasis and Alters the Response to Inflammation

    PubMed Central

    Asperti, Michela; Stuemler, Tanja; Poli, Maura; Gryzik, Magdalena; Lifshitz, Lena; Meyron-Holtz, Esther G.; Vlodavsky, Israel

    2016-01-01

    Hepcidin is the key regulator of systemic iron availability that acts by controlling the degradation of the iron exporter ferroportin. It is expressed mainly in the liver and regulated by iron, inflammation, erythropoiesis and hypoxia. The various agents that control its expression act mainly via the BMP6/SMAD signaling pathway. Among them are exogenous heparins, which are strong hepcidin repressors with a mechanism of action not fully understood but that may involve the competition with the structurally similar endogenous Heparan Sulfates (HS). To verify this hypothesis, we analyzed how the overexpression of heparanase, the HS degrading enzyme, modified hepcidin expression and iron homeostasis in hepatic cell lines and in transgenic mice. The results showed that transient and stable overexpression of heparanase in HepG2 cells caused a reduction of hepcidin expression and of SMAD5 phosphorylation. Interestingly, the clones showed also altered level of TfR1 and ferritin, indices of a modified iron homeostasis. The heparanase transgenic mice showed a low level of liver hepcidin, an increase of serum and liver iron with a decrease in spleen iron content. The hepcidin expression remained surprisingly low even after treatment with the inflammatory LPS. The finding that modification of HS structure mediated by heparanase overexpression affects hepcidin expression and iron homeostasis supports the hypothesis that HS participate in the mechanisms controlling hepcidin expression. PMID:27711215

  12. Ustilago maydis natural antisense transcript expression alters mRNA stability and pathogenesis

    PubMed Central

    Donaldson, Michael E; Saville, Barry J

    2013-01-01

    Ustilago maydis infection of Zea mays leads to the production of thick-walled diploid teliospores that are the dispersal agent for this pathogen. Transcriptome analyses of this model biotrophic basidiomycete fungus identified natural antisense transcripts (NATs) complementary to 247 open reading frames. The U. maydis NAT cDNAs were fully sequenced and annotated. Strand-specific RT-PCR screens confirmed expression and identified NATs preferentially expressed in the teliospore. Targeted screens revealed four U. maydis NATs that are conserved in a related fungus. Expression of NATs in haploid cells, where they are not naturally occurring, resulted in increased steady-state levels of some complementary mRNAs. The expression of one NAT, as-um02151, in haploid cells resulted in a twofold increase in complementary mRNA levels, the formation of sense–antisense double-stranded RNAs, and unchanged Um02151 protein levels. This led to a model for NAT function in the maintenance and expression of stored teliospore mRNAs. In testing this model by deletion of the regulatory region, it was determined that alteration in NAT expression resulted in decreased pathogenesis in both cob and seedling infections. This annotation and functional analysis supports multiple roles for U. maydis NATs in controlling gene expression and influencing pathogenesis. PMID:23650872

  13. Ustilago maydis natural antisense transcript expression alters mRNA stability and pathogenesis.

    PubMed

    Donaldson, Michael E; Saville, Barry J

    2013-07-01

    Ustilago maydis infection of Zea mays leads to the production of thick-walled diploid teliospores that are the dispersal agent for this pathogen. Transcriptome analyses of this model biotrophic basidiomycete fungus identified natural antisense transcripts (NATs) complementary to 247 open reading frames. The U. maydis NAT cDNAs were fully sequenced and annotated. Strand-specific RT-PCR screens confirmed expression and identified NATs preferentially expressed in the teliospore. Targeted screens revealed four U. maydis NATs that are conserved in a related fungus. Expression of NATs in haploid cells, where they are not naturally occurring, resulted in increased steady-state levels of some complementary mRNAs. The expression of one NAT, as-um02151, in haploid cells resulted in a twofold increase in complementary mRNA levels, the formation of sense-antisense double-stranded RNAs, and unchanged Um02151 protein levels. This led to a model for NAT function in the maintenance and expression of stored teliospore mRNAs. In testing this model by deletion of the regulatory region, it was determined that alteration in NAT expression resulted in decreased pathogenesis in both cob and seedling infections. This annotation and functional analysis supports multiple roles for U. maydis NATs in controlling gene expression and influencing pathogenesis.

  14. Ustilago maydis natural antisense transcript expression alters mRNA stability and pathogenesis.

    PubMed

    Donaldson, Michael E; Saville, Barry J

    2013-07-01

    Ustilago maydis infection of Zea mays leads to the production of thick-walled diploid teliospores that are the dispersal agent for this pathogen. Transcriptome analyses of this model biotrophic basidiomycete fungus identified natural antisense transcripts (NATs) complementary to 247 open reading frames. The U. maydis NAT cDNAs were fully sequenced and annotated. Strand-specific RT-PCR screens confirmed expression and identified NATs preferentially expressed in the teliospore. Targeted screens revealed four U. maydis NATs that are conserved in a related fungus. Expression of NATs in haploid cells, where they are not naturally occurring, resulted in increased steady-state levels of some complementary mRNAs. The expression of one NAT, as-um02151, in haploid cells resulted in a twofold increase in complementary mRNA levels, the formation of sense-antisense double-stranded RNAs, and unchanged Um02151 protein levels. This led to a model for NAT function in the maintenance and expression of stored teliospore mRNAs. In testing this model by deletion of the regulatory region, it was determined that alteration in NAT expression resulted in decreased pathogenesis in both cob and seedling infections. This annotation and functional analysis supports multiple roles for U. maydis NATs in controlling gene expression and influencing pathogenesis. PMID:23650872

  15. Vitamin A facilitates enteric nervous system precursor migration by reducing Pten accumulation

    PubMed Central

    Fu, Ming; Sato, Yoshiharu; Lyons-Warren, Ariel; Zhang, Bin; Kane, Maureen A.; Napoli, Joseph L.; Heuckeroth, Robert O.

    2010-01-01

    Hirschsprung disease is a serious disorder of enteric nervous system (ENS) development caused by the failure of ENS precursor migration into the distal bowel. We now demonstrate that retinoic acid (RA) is crucial for GDNF-induced ENS precursor migration, cell polarization and lamellipodia formation, and that vitamin A depletion causes distal bowel aganglionosis in serum retinol-binding-protein-deficient (Rbp4–/–) mice. Ret heterozygosity increases the incidence and severity of distal bowel aganglionosis induced by vitamin A deficiency in Rbp4–/– animals. Furthermore, RA reduces phosphatase and tensin homolog (Pten) accumulation in migrating cells, whereas Pten overexpression slows ENS precursor migration. Collectively, these data support the hypothesis that vitamin A deficiency is a non-genetic risk factor that increases Hirschsprung disease penetrance and expressivity, suggesting that some cases of Hirschsprung disease might be preventable by optimizing maternal nutrition. PMID:20110328

  16. Oestradiol and progesterone differentially alter cytoskeletal protein expression and flame cell morphology in Taenia crassiceps.

    PubMed

    Ambrosio, Javier R; Ostoa-Saloma, Pedro; Palacios-Arreola, M Isabel; Ruíz-Rosado, Azucena; Sánchez-Orellana, Pedro L; Reynoso-Ducoing, Olivia; Nava-Castro, Karen E; Martínez-Velázquez, Nancy; Escobedo, Galileo; Ibarra-Coronado, Elizabeth G; Valverde-Islas, Laura; Morales-Montor, Jorge

    2014-09-01

    We examined the effects of oestradiol (E2) and progesterone (P4) on cytoskeletal protein expression in the helminth Taenia crassiceps - specifically actin, tubulin and myosin. These proteins assemble into flame cells, which constitute the parasite excretory system. Total protein extracts were obtained from E2- and P4-treated T. crassiceps cysticerci and untreated controls, and analysed by one- and two-dimensional protein electrophoresis, flow cytometry, immunofluorescence and videomicroscopy. Exposure of T. crassiceps cysticerci to E2 and P4 induced differential protein expression patterns compared with untreated controls. Changes in actin, tubulin and myosin expression were confirmed by flow cytometry of parasite cells and immunofluorescence. In addition, parasite morphology was altered in response to E2 and P4 versus controls. Flame cells were primarily affected at the level of the ciliary tuft, in association with the changes in actin, tubulin and myosin. We conclude that oestradiol and progesterone act directly on T. crassiceps cysticerci, altering actin, tubulin and myosin expression and thus affecting the assembly and function of flame cells. Our results increase our understanding of several aspects of the molecular crosstalk between host and parasite, which might be useful in designing anthelmintic drugs that exclusively impair parasitic proteins which mediate cell signaling and pathogenic reproduction and establishment.

  17. A not cytotoxic nickel concentration alters the expression of neuronal differentiation markers in NT2 cells.

    PubMed

    Ceci, Claudia; Barbaccia, Maria Luisa; Pistritto, Giuseppa

    2015-03-01

    Nickel, a known occupational/environmental hazard, may cross the placenta and reach appreciable concentrations in various fetal organs, including the brain. The aim of this study was to investigate whether nickel interferes with the process of neuronal differentiation. Following a 4 week treatment with retinoic acid (10μM), the human teratocarcinoma-derived NTera2/D1 cell line (NT2 cells) terminally differentiate into neurons which recapitulate many features of human fetal neurons. The continuous exposure of the differentiating NT2 cells to a not cytotoxic nickel concentration (10μM) increased the expression of specific neuronal differentiation markers such as neural cell adhesion molecule (NCAM) and microtubule associated protein 2 (MAP2). Furthermore, nickel exposure increased the expression of hypoxia-inducible-factor-1α (HIF-1α) and induced the activation of the AKT/PKB kinase pathway, as shown by the increase of P(Ser-9)-GSK-3β, the inactive form of glycogen synthase kinase-3β (GSK-3β). Intriguingly, by the end of the fourth week the expression of tyrosine hydroxylase (TH) protein, a marker of dopaminergic neurons, was lower in nickel-treated than in control cultures. Thus, likely by partially mimicking hypoxic conditions, a not-cytotoxic nickel concentration appears to alter the process of neuronal differentiation and hinder the expression of the dopaminergic neuronal phenotype. Taken together, these results suggest that nickel, by altering normal brain development, may increase susceptibility to neuro-psychopathology later in life.

  18. Analysis of microdissected neurons by 18O mass spectrometry reveals altered protein expression in Alzheimer's disease

    PubMed Central

    Hashimoto, Masakazu; Bogdanovic, Nenad; Nakagawa, Hiroyuki; Volkmann, Inga; Aoki, Mikio; Winblad, Bengt; Sakai, Jun; Tjernberg, Lars O

    2012-01-01

    Abstract It is evident that the symptoms of Alzheimer's disease (AD) are derived from severe neuronal damage, and especially pyramidal neurons in the hippocampus are affected pathologically. Here, we analysed the proteome of hippocampal neurons, isolated from post-mortem brains by laser capture microdissection. By using 18O labelling and mass spectrometry, the relative expression levels of 150 proteins in AD and controls were estimated. Many of the identified proteins are involved in transcription and nucleotide binding, glycolysis, heat-shock response, microtubule stabilization, axonal transport or inflammation. The proteins showing the most altered expression in AD were selected for immunohistochemical analysis. These analyses confirmed the altered expression levels, and showed in many AD cases a pathological pattern. For comparison, we also analysed hippocampal sections by Western blot. The expression levels found by this method showed poor correlation with the neuron-specific analysis. Hence, we conclude that cell-specific proteome analysis reveals differences in the proteome that cannot be detected by bulk analysis. PMID:21883897

  19. Variance of gene expression identifies altered network constraints in neurological disease.

    PubMed

    Mar, Jessica C; Matigian, Nicholas A; Mackay-Sim, Alan; Mellick, George D; Sue, Carolyn M; Silburn, Peter A; McGrath, John J; Quackenbush, John; Wells, Christine A

    2011-08-01

    Gene expression analysis has become a ubiquitous tool for studying a wide range of human diseases. In a typical analysis we compare distinct phenotypic groups and attempt to identify genes that are, on average, significantly different between them. Here we describe an innovative approach to the analysis of gene expression data, one that identifies differences in expression variance between groups as an informative metric of the group phenotype. We find that genes with different expression variance profiles are not randomly distributed across cell signaling networks. Genes with low-expression variance, or higher constraint, are significantly more connected to other network members and tend to function as core members of signal transduction pathways. Genes with higher expression variance have fewer network connections and also tend to sit on the periphery of the cell. Using neural stem cells derived from patients suffering from Schizophrenia (SZ), Parkinson's disease (PD), and a healthy control group, we find marked differences in expression variance in cell signaling pathways that shed new light on potential mechanisms associated with these diverse neurological disorders. In particular, we find that expression variance of core networks in the SZ patient group was considerably constrained, while in contrast the PD patient group demonstrated much greater variance than expected. One hypothesis is that diminished variance in SZ patients corresponds to an increased degree of constraint in these pathways and a corresponding reduction in robustness of the stem cell networks. These results underscore the role that variation plays in biological systems and suggest that analysis of expression variance is far more important in disease than previously recognized. Furthermore, modeling patterns of variability in gene expression could fundamentally alter the way in which we think about how cellular networks are affected by disease processes.

  20. Altered gene expression profiles in the hippocampus and prefrontal cortex of type 2 diabetic rats

    PubMed Central

    2012-01-01

    Background There has been an increasing body of epidemiologic and biochemical evidence implying the role of cerebral insulin resistance in Alzheimer-type dementia. For a better understanding of the insulin effect on the central nervous system, we performed microarray-based global gene expression profiling in the hippocampus, striatum and prefrontal cortex of streptozotocin-induced and spontaneously diabetic Goto-Kakizaki rats as model animals for type 1 and type 2 diabetes, respectively. Results Following pathway analysis and validation of gene lists by real-time polymerase chain reaction, 30 genes from the hippocampus, such as the inhibitory neuropeptide galanin, synuclein gamma and uncoupling protein 2, and 22 genes from the prefrontal cortex, e.g. galanin receptor 2, protein kinase C gamma and epsilon, ABCA1 (ATP-Binding Cassette A1), CD47 (Cluster of Differentiation 47) and the RET (Rearranged During Transfection) protooncogene, were found to exhibit altered expression levels in type 2 diabetic model animals in comparison to non-diabetic control animals. These gene lists proved to be partly overlapping and encompassed genes related to neurotransmission, lipid metabolism, neuronal development, insulin secretion, oxidative damage and DNA repair. On the other hand, no significant alterations were found in the transcriptomes of the corpus striatum in the same animals. Changes in the cerebral gene expression profiles seemed to be specific for the type 2 diabetic model, as no such alterations were found in streptozotocin-treated animals. Conclusions According to our knowledge this is the first characterization of the whole-genome expression changes of specific brain regions in a diabetic model. Our findings shed light on the complex role of insulin signaling in fine-tuning brain functions, and provide further experimental evidence in support of the recently elaborated theory of type 3 diabetes. PMID:22369239

  1. Persistent Alterations of Gene Expression Profiling of Human Peripheral Blood Mononuclear Cells From Smokers

    PubMed Central

    Weng, Daniel Y.; Chen, Jinguo; Taslim, Cenny; Hsu, Ping-Ching; Marian, Catalin; David, Sean P.; Loffredo, Christopher A.; Shields, Peter G.

    2016-01-01

    The number of validated biomarkers of tobacco smoke exposure is limited, and none exist for tobacco-related cancer. Additional biomarkers for smoke, effects on cellular systems in vivo are needed to improve early detection of lung cancer, and to assist the Food and Drug Administration in regulating exposures to tobacco products. We assessed the effects of smoking on the gene expression using human cell cultures and blood from a cross-sectional study. We profiled global transcriptional changes in cultured smokers’ peripheral blood mononuclear cells (PBMCs) treated with cigarette smoke condensate (CSC) in vitro (n = 7) and from well-characterized smokers’ blood (n = 36). ANOVA with adjustment for covariates and Pearson correlation were used for statistical analysis in this study. CSC in vitro altered the expression of 1 178 genes (177 genes with > 1.5-fold-change) at P < 0.05. In vivo, PBMCs of heavy and light smokers differed for 614 genes (29 with > 1.5-fold-change) at P < 0.05 (309 remaining significant after adjustment for age, race, and gender). Forty-one genes were persistently altered both in vitro and in vivo, 22 having the same expression pattern reported for non-small cell lung cancer. Our data provides evidence that persistent alterations of gene expression in vitro and in vivo may relate to carcinogenic effects of cigarette smoke, and the identified genes may serve as potential biomarkers for cancer. The use of an in vitro model to corroborate results from human studies provides a novel way to understand human exposure and effect. PMID:26294040

  2. Altered Gene Expression Pattern in Peripheral Blood Mononuclear Cells in Patients with Acute Myocardial Infarction

    PubMed Central

    Kiliszek, Marek; Burzynska, Beata; Michalak, Marcin; Gora, Monika; Winkler, Aleksandra; Maciejak, Agata; Leszczynska, Agata; Gajda, Ewa; Kochanowski, Janusz; Opolski, Grzegorz

    2012-01-01

    Background Despite a substantial progress in diagnosis and therapy, acute myocardial infarction (MI) is a major cause of mortality in the general population. A novel insight into the pathophysiology of myocardial infarction obtained by studying gene expression should help to discover novel biomarkers of MI and to suggest novel strategies of therapy. The aim of our study was to establish gene expression patterns in leukocytes from acute myocardial infarction patients. Methods and Results Twenty-eight patients with ST-segment elevation myocardial infarction (STEMI) were included. The blood was collected on the 1st day of myocardial infarction, after 4–6 days, and after 6 months. Control group comprised 14 patients with stable coronary artery disease, without history of myocardial infarction. Gene expression analysis was performed with Affymetrix Human Gene 1.0 ST microarrays and GCS3000 TG system. Lists of genes showing altered expression levels (fold change >1.5, p<0.05) were submitted to Ingenuity Pathway Analysis. Gene lists from each group were examined for canonical pathways and molecular and cellular functions. Comparing acute phase of MI with the same patients after 6 months (stable phase) and with control group we found 24 genes with changed expression. In canonical analysis three pathways were highlighted: signaling of PPAR (peroxisome proliferator-activated receptor), IL-10 and IL-6 (interleukin 10 and 6). Conclusions In the acute phase of STEMI, dozens of genes from several pathways linked with lipid/glucose metabolism, platelet function and atherosclerotic plaque stability show altered expression. Up-regulation of SOCS3 and FAM20 genes in the first days of myocardial infarction is observed in the vast majority of patients. PMID:23185530

  3. Inhalation of Ultrafine Particles Alters Blood Leukocyte Expression of Adhesion Molecules in Humans

    PubMed Central

    Frampton, Mark W.; Stewart, Judith C.; Oberdörster, Günter; Morrow, Paul E.; Chalupa, David; Pietropaoli, Anthony P.; Frasier, Lauren M.; Speers, Donna M.; Cox, Christopher; Huang, Li-Shan; Utell, Mark J.

    2006-01-01

    Ultrafine particles (UFPs; aerodynamic diameter < 100 nm) may contribute to the respiratory and cardiovascular morbidity and mortality associated with particulate air pollution. We tested the hypothesis that inhalation of carbon UFPs has vascular effects in healthy and asthmatic subjects, detectable as alterations in blood leukocyte expression of adhesion molecules. Healthy subjects inhaled filtered air and freshly generated elemental carbon particles (count median diameter ~ 25 nm, geometric standard deviation ~ 1.6), for 2 hr, in three separate protocols: 10 μg/m3 at rest, 10 and 25 μg/m3 with exercise, and 50 μg/m3 with exercise. In a fourth protocol, subjects with asthma inhaled air and 10 μg/m3 UFPs with exercise. Peripheral venous blood was obtained before and at intervals after exposure, and leukocyte expression of surface markers was quantitated using multiparameter flow cytometry. In healthy subjects, particle exposure with exercise reduced expression of adhesion molecules CD54 and CD18 on monocytes and CD18 and CD49d on granulocytes. There were also concentration-related reductions in blood monocytes, basophils, and eosinophils and increased lymphocyte expression of the activation marker CD25. In subjects with asthma, exposure with exercise to 10 μg/m3 UFPs reduced expression of CD11b on monocytes and eosinophils and CD54 on granulocytes. Particle exposure also reduced the percentage of CD4+ T cells, basophils, and eosinophils. Inhalation of elemental carbon UFPs alters peripheral blood leukocyte distribution and expression of adhesion molecules, in a pattern consistent with increased retention of leukocytes in the pulmonary vascular bed. PMID:16393658

  4. Neonatal Bisphenol A exposure alters sexually dimorphic gene expression in the postnatal rat hypothalamus.

    PubMed

    Cao, Jinyan; Mickens, Jillian A; McCaffrey, Katherine A; Leyrer, Stephanie M; Patisaul, Heather B

    2012-01-01

    Developmental exposure to Bisphenol A (BPA), a component of polycarbonate and epoxy resins, has been purported to adversely impact reproductive function in female rodents. Because neonatal life is a critical window for the sexual dimorphic organization of the hypothalamic-pituitary-gonadal (HPG) axis, interference with this process could underlie compromised adult reproductive physiology. The goal of the present study was to determine if neonatal BPA exposure interferes with sex specific gene expression of estrogen receptor alpha (ERα), ER beta (ERβ) and kisspeptin (Kiss1) in the anterior and mediobasal hypothalamus. Long Evans (LE) neonatal rats were exposed to vehicle, 10μg estradiol benzoate (EB), 50mg/kg BPA or 50μg/kg BPA by subcutaneous injection daily from postnatal day 0 (PND 0) to PND 2. Gene expression was assessed by in situ hybridization on PNDs 4 and 10. Within the anterior hypothalamus ERα expression was augmented by BPA in PND 4 females, then fell to male-typical levels by PND 10. ERβ expression was not altered by BPA on PND 4, but significantly decreased or eliminated in both sexes by PND 10. Kiss1 expression was diminished by BPA in the anterior hypothalamus, especially in females. There were no significant impacts of BPA in the mediobasal hypothalamus. Collectively, BPA effects did not mirror those of EB. The results show that neonatal hypothalamic ER and Kiss1 expression is sensitive to BPA exposure. This disruption may alter sexually dimorphic hypothalamic organization and underlie adult reproductive deficiencies. Additionally, the discordant effects of EB and BPA indicate that BPA likely disrupts hypothalamic organization by a mechanism other than simply acting as an estrogen mimic.

  5. Altered Protein Composition and Gene Expression in Strabismic Human Extraocular Muscles and Tendons

    PubMed Central

    Agarwal, Andrea B.; Feng, Cheng-Yuan; Altick, Amy L.; Quilici, David R.; Wen, Dan; Johnson, L. Alan; von Bartheld, Christopher S.

    2016-01-01

    Purpose To determine whether structural protein composition and expression of key regulatory genes are altered in strabismic human extraocular muscles. Methods Samples from strabismic horizontal extraocular muscles were obtained during strabismus surgery and compared with normal muscles from organ donors. We used proteomics, standard and customized PCR arrays, and microarrays to identify changes in major structural proteins and changes in gene expression. We focused on muscle and connective tissue and its control by enzymes, growth factors, and cytokines. Results Strabismic muscles showed downregulation of myosins, tropomyosins, troponins, and titin. Expression of collagens and regulators of collagen synthesis and degradation, the collagenase matrix metalloproteinase (MMP)2 and its inhibitors, tissue inhibitor of metalloproteinase (TIMP)1 and TIMP2, was upregulated, along with tumor necrosis factor (TNF), TNF receptors, and connective tissue growth factor (CTGF), as well as proteoglycans. Growth factors controlling extracellular matrix (ECM) were also upregulated. Among 410 signaling genes examined by PCR arrays, molecules with downregulation in the strabismic phenotype included GDNF, NRG1, and PAX7; CTGF, CXCR4, NPY1R, TNF, NTRK1, and NTRK2 were upregulated. Signaling molecules known to control extraocular muscle plasticity were predominantly expressed in the tendon rather than the muscle component. The two horizontal muscles, medial and lateral rectus, displayed similar changes in protein and gene expression, and no obvious effect of age. Conclusions Quantification of proteins and gene expression showed significant differences in the composition of extraocular muscles of strabismic patients with respect to important motor proteins, elements of the ECM, and connective tissue. Therefore, our study supports the emerging view that the molecular composition of strabismic muscles is substantially altered. PMID:27768799

  6. Levonorgestrel enhances spermatogenesis suppression by testosterone with greater alteration in testicular gene expression in men.

    PubMed

    Lue, YanHe; Wang, Christina; Cui, YuGui; Wang, XingHai; Sha, JiaHao; Zhou, ZuoMin; Xu, Jun; Wang, Charles; Hikim, Amiya P Sinha; Swerdloff, Ronald S

    2009-03-01

    Prior studies have demonstrated that combined treatment of testosterone with a progestin induces a more rapid and greater suppression of spermatogenesis than testosterone treatment alone. We hypothesized that the suppressive effects of the combination of testosterone undecanoate (TU) injections plus oral levonorgestrel (LNG) on spermatogenesis may be mediated through a greater perturbation of testicular gene expression than TU alone. To test this hypothesis, we performed open testicular biopsy on 12 different adult healthy subjects: 1) four healthy men as controls; 2) four men 2 wk after TU treatment; and 3) four men 2 wk after TU + LNG administration. RNA isolated from biopsies was used for DNA microarray using the Affymetrix Human Genome U133 Plus 2.0 oligonucleotide microarrays. Gene expression with >or=2-fold changes (P < 0.05) compared with control was analyzed using the National Institutes of Health Database for Annotation, Visualization, and Integrated Discovery 2008 resource. The TU treatment altered the gene expression in 109 transcripts, whereas TU + LNG altered the gene expression in 207 transcripts compared with control. Both TU and TU + LNG administration suppressed gene expression of insulin-like 3; cytochrome P450, family 17, subfamily A1 in Leydig cells; and inhibin alpha in Sertoli cells; they increased proapoptotic transcripts BCL2-like 14, insulin-like growth factor-binding protein 3; and they decreased X-linked inhibitor of apoptosis protein. In comparison with TU treatment alone, TU + LNG treatment upregulated insulin-like 6 and relaxin 1, and downregulated RNA-binding protein transcripts. We conclude that TU + LNG administration induces more changes in testicular gene expression than TU alone. This exploratory study provided a novel and valuable database to study the mechanisms of action of hormonal regulation of spermatogenesis in men and identified testicular-specific molecules that may serve as potential targets for male contraceptive

  7. Alteration of Connective Tissue Growth Factor (CTGF) Expression in Orbital Fibroblasts from Patients with Graves’ Ophthalmopathy

    PubMed Central

    Chang, Pei-Chen; Wei, Yau-Huei

    2015-01-01

    Graves’ ophthalmopathy (GO) is a disfiguring and sometimes blinding disease, which is characterized by inflammation and swelling of orbital tissues, with fibrosis and adipogenesis being predominant features. The aim of this study is to investigate whether the expression levels of fibrosis-related genes, especially that of connective tissue growth factor (CTGF), are altered in orbital fibroblasts of patients with GO. The role of oxidative stress in the regulation of CTGF expression in GO orbital fibroblasts is also examined. By a SYBR Green-based real time quantitative PCR (RT-QPCR), we demonstrated that the mRNA expression levels of fibronectin, apolipoprotein J, and CTGF in cultured orbital fibroblasts from patients with GO were significantly higher than those of age-matched normal controls (p = 0.007, 0.037, and 0.002, respectively). In addition, the protein expression levels of fibronectin, apolipoprotein J, and CTGF analyzed by Western blot were also significantly higher in GO orbital fibroblasts (p = 0.046, 0.032, and 0.008, respectively) as compared with the control. Furthermore, after treatment of orbital fibroblasts with a sub-lethal dose of hydrogen peroxide (200 μM H2O2), we found that the H2O2-induced increase of CTGF expression was more pronounced in the GO orbital fibroblasts as compared with those in normal controls (20% vs. 7%, p = 0.007). Importantly, pre-incubation with antioxidants including N-acetylcysteine (NAC) and vitamin C, respectively, resulted in significant attenuation of the induction of CTGF in GO orbital fibroblasts in response to H2O2 (p = 0.004 and 0.015, respectively). Taken together, we suggest that oxidative stress plays a role in the alteration of the expression of CTGF in GO orbital fibroblasts that may contribute to the pathogenesis and progression of GO. Antioxidants may be used in combination with the therapeutic agents for effective treatment of GO. PMID:26599235

  8. Ethanol-related alterations in gene expression patterns in the developing murine hippocampus.

    PubMed

    Mandal, Chanchal; Park, Kyoung Sun; Jung, Kyoung Hwa; Chai, Young Gyu

    2015-08-01

    It is well known that consuming alcohol prior to and during pregnancy can cause harm to the developing fetus. Fetal alcohol spectrum disorder is a term commonly used to describe a range of disabilities that may arise from prenatal alcohol exposure such as fetal alcohol syndrome, partial fetal alcohol syndrome, alcohol-related neurodevelopmental disorders, and alcohol-related birth defects. Here, we report that maternal binge alcohol consumption alters several important genes that are involved in nervous system development in the mouse hippocampus at embryonic day 18. Microarray analysis revealed that Nova1, Ntng1, Gal, Neurog2, Neurod2, and Fezf2 gene expressions are altered in the fetal hippocampus. Pathway analysis also revealed the association of the calcium signaling pathway in addition to other pathways with the differentially expressed genes during early brain development. Alteration of such important genes and dynamics of the signaling pathways may cause neurodevelopmental disorders. Our findings offer insight into the molecular mechanism involved in neurodevelopmental disorders associated with alcohol-related defects.

  9. Ethanol-related alterations in gene expression patterns in the developing murine hippocampus.

    PubMed

    Mandal, Chanchal; Park, Kyoung Sun; Jung, Kyoung Hwa; Chai, Young Gyu

    2015-08-01

    It is well known that consuming alcohol prior to and during pregnancy can cause harm to the developing fetus. Fetal alcohol spectrum disorder is a term commonly used to describe a range of disabilities that may arise from prenatal alcohol exposure such as fetal alcohol syndrome, partial fetal alcohol syndrome, alcohol-related neurodevelopmental disorders, and alcohol-related birth defects. Here, we report that maternal binge alcohol consumption alters several important genes that are involved in nervous system development in the mouse hippocampus at embryonic day 18. Microarray analysis revealed that Nova1, Ntng1, Gal, Neurog2, Neurod2, and Fezf2 gene expressions are altered in the fetal hippocampus. Pathway analysis also revealed the association of the calcium signaling pathway in addition to other pathways with the differentially expressed genes during early brain development. Alteration of such important genes and dynamics of the signaling pathways may cause neurodevelopmental disorders. Our findings offer insight into the molecular mechanism involved in neurodevelopmental disorders associated with alcohol-related defects. PMID:26063602

  10. Systems biology reveals new strategies for personalizing cancer medicine and confirms the role of PTEN in resistance to trastuzumab.

    PubMed

    Faratian, Dana; Goltsov, Alexey; Lebedeva, Galina; Sorokin, Anatoly; Moodie, Stuart; Mullen, Peter; Kay, Charlene; Um, In Hwa; Langdon, Simon; Goryanin, Igor; Harrison, David J

    2009-08-15

    Resistance to targeted cancer therapies such as trastuzumab is a frequent clinical problem not solely because of insufficient expression of HER2 receptor but also because of the overriding activation states of cell signaling pathways. Systems biology approaches lend themselves to rapid in silico testing of factors, which may confer resistance to targeted therapies. Inthis study, we aimed to develop a new kinetic model that could be interrogated to predict resistance to receptor tyrosine kinase (RTK) inhibitor therapies and directly test predictions in vitro and in clinical samples. The new mathematical model included RTK inhibitor antibody binding, HER2/HER3 dimerization and inhibition, AKT/mitogen-activated protein kinase cross-talk, and the regulatory properties of PTEN. The model was parameterized using quantitative phosphoprotein expression data from cancer cell lines using reverse-phase protein microarrays. Quantitative PTEN protein expression was found to be the key determinant of resistance to anti-HER2 therapy in silico, which was predictive of unseen experiments in vitro using the PTEN inhibitor bp(V). When measured in cancer cell lines, PTEN expression predicts sensitivity to anti-HER2 therapy; furthermore, this quantitative measurement is more predictive of response (relative risk, 3.0; 95% confidence interval, 1.6-5.5; P < 0.0001) than other pathway components taken in isolation and when tested by multivariate analysis in a cohort of 122 breast cancers treated with trastuzumab. For the first time, a systems biology approach has successfully been used to stratify patients for personalized therapy in cancer and is further compelling evidence that PTEN, appropriately measured in the clinical setting, refines clinical decision making in patients treated with anti-HER2 therapies.

  11. Simulated microgravity alters the expression of key genes involved in fracture healing

    NASA Astrophysics Data System (ADS)

    McCabe, N. Patrick; Androjna, Caroline; Hill, Esther; Globus, Ruth K.; Midura, Ronald J.

    2013-11-01

    Fracture healing in animal models has been shown to be altered in both ground based analogs of spaceflight and in those exposed to actual spaceflight. The molecular mechanisms behind altered fracture healing as a result of chronic exposure to microgravity remain to be elucidated. This study investigates temporal gene expression of multiple factors involved in secondary fracture healing, specifically those integral to the development of a soft tissue callus and the transition to that of hard tissue. Skeletally mature female rats were subjected to a 4 week period of simulated microgravity and then underwent a closed femoral fracture procedure. Thereafter, they were reintroduced to the microgravity and allowed to heal for a 1 or 2 week period. A synchronous group of weight bearing rats was used as a normal fracture healing control. Utilizing Real-Time quantitative PCR on mRNA from fracture callus tissue, we found significant reductions in the levels of transcripts associated with angiogenesis, chondrogenesis, and osteogenesis. These data suggest an altered fracture healing process in a simulated microgravity environment, and these alterations begin early in the healing process. These findings may provide mechanistic insight towards developing countermeasure protocols to mitigate these adaptations.

  12. Progressive alterations of cytokeratin expressions in the process of chronic arsenism.

    PubMed

    Yu, H S; Chiou, K S; Chen, G S; Yang, R C; Chang, S F

    1993-12-01

    Recent studies of an endemic occurrence of chronic arsenism in a limited area on the southwest coast of Taiwan are focusing on its cytokeratin analysis in hopes of tracing the disease's biochemical expression. Specimens were obtained from uninvolved skin and arsenical cancers including Bowen's disease, basal cell carcinoma, and squamous cell carcinoma. In this study, we used two-dimensional polyacrylamide gel electrophoresis to analyse cytokeratin expression. Progressive alterations in cytokeratin expression were found in various skin lesions. These include an expression of K16 in the uninvolved skin; K16 and K6 in Bowen's disease; and K16, K6 and K17 in squamous cell carcinoma and basal cell carcinoma. In addition, we found that the K1 isoelectric variants shifted to more acidic forms with the complete absence of K1 in basal cell carcinoma. K16 expression in uninvolved skin indicates that it is nevertheless in a hyperproliferative status. K17 was expressed in squamous cell carcinoma and basal cell carcinoma, but not in Bowen's disease. The progressive impairment of phosphorylation of K1 and K2 in the process of chronic arsenism provides us with a suitable model for studying the biological significance of phosphorylation in intermediate filaments during chemical carcinogenesis.

  13. Preliminary evidence of phenytoin-induced alterations in embryonic gene expression in a mouse model.

    PubMed

    Musselman, A C; Bennett, G D; Greer, K A; Eberwine, J H; Finnell, R H

    1994-01-01

    SWV mouse embryos collected on gestational days (GD) 9:12 and 10:00 following chronic in utero exposure to teratogenic concentrations of phenytoin were utilized for in situ transcription studies of gene expression. The substrate cDNA obtained from the frozen embryo sections was amplified into radiolabelled antisense RNA (RT/aRNA) and used as a probe to screen a panel of 20 cDNA clones representing genes that are important regulators of craniofacial and neural development. The magnitude of alteration in gene expression following phenytoin treatment was determined densitometrically by changes in the hybridization intensity of the aRNA probes to the cDNA clones immobilized to the slot blots. We found that both Wnt-1 and the calcium channel gene were developmentally regulated, as their level of expression decreased significantly between the two collection times. Phenytoin treatment produced a significant downregulation in the level of expression for 25% of the genes examined in the GD 9:12 embryos, including the growth factors TGF-beta and NT3, the proto-oncogene Wnt-1, the nicotinic receptor, and the voltage sensitive calcium channel gene. Additional changes in the coordinate expression of several of the growth and transcription factors were observed at both gestational timepoints. The application of RT/aRNA technology has extended our appreciation of the normal patterns of gene expression during craniofacial and neural development, and provided the first demonstration of multiple coordinate changes in transcription patterns following teratogenic insult.

  14. Manipulation of BK channel expression is sufficient to alter auditory hair cell thresholds in larval zebrafish

    PubMed Central

    Rohmann, Kevin N.; Tripp, Joel A.; Genova, Rachel M.; Bass, Andrew H.

    2014-01-01

    Non-mammalian vertebrates rely on electrical resonance for frequency tuning in auditory hair cells. A key component of the resonance exhibited by these cells is an outward calcium-activated potassium current that flows through large-conductance calcium-activated potassium (BK) channels. Previous work in midshipman fish (Porichthys notatus) has shown that BK expression correlates with seasonal changes in hearing sensitivity and that pharmacologically blocking these channels replicates the natural decreases in sensitivity during the winter non-reproductive season. To test the hypothesis that reducing BK channel function is sufficient to change auditory thresholds in fish, morpholino oligonucleotides (MOs) were used in larval zebrafish (Danio rerio) to alter expression of slo1a and slo1b, duplicate genes coding for the pore-forming α-subunits of BK channels. Following MO injection, microphonic potentials were recorded from the inner ear of larvae. Quantitative real-time PCR was then used to determine the MO effect on slo1a and slo1b expression in these same fish. Knockdown of either slo1a or slo1b resulted in disrupted gene expression and increased auditory thresholds across the same range of frequencies of natural auditory plasticity observed in midshipman. We conclude that interference with the normal expression of individual slo1 genes is sufficient to increase auditory thresholds in zebrafish larvae and that changes in BK channel expression are a direct mechanism for regulation of peripheral hearing sensitivity among fishes. PMID:24803460

  15. Consistently altered expression of gene sets in postmortem brains of individuals with major psychiatric disorders

    PubMed Central

    Darby, M M; Yolken, R H; Sabunciyan, S

    2016-01-01

    The measurement of gene expression in postmortem brain is an important tool for understanding the pathogenesis of serious psychiatric disorders. We hypothesized that major molecular deficits associated with psychiatric disease would affect the entire brain, and such deficits may be shared across disorders. We performed RNA sequencing and quantified gene expression in the hippocampus of 100 brains in the Stanley Array Collection followed by replication in the orbitofrontal cortex of 57 brains in the Stanley Neuropathology Consortium. We then identified genes and canonical pathway gene sets with significantly altered expression in schizophrenia and bipolar disorder in the hippocampus and in schizophrenia, bipolar disorder and major depression in the orbitofrontal cortex. Although expression of individual genes varied, gene sets were significantly enriched in both of the brain regions, and many of these were consistent across diagnostic groups. Further examination of core gene sets with consistently increased or decreased expression in both of the brain regions and across target disorders revealed that ribosomal genes are overexpressed while genes involved in neuronal processes, GABAergic signaling, endocytosis and antigen processing have predominantly decreased expression in affected individuals compared to controls without a psychiatric disorder. Our results highlight pathways of central importance to psychiatric health and emphasize messenger RNA processing and protein synthesis as potential therapeutic targets for all three of the disorders. PMID:27622934

  16. Consistently altered expression of gene sets in postmortem brains of individuals with major psychiatric disorders.

    PubMed

    Darby, M M; Yolken, R H; Sabunciyan, S

    2016-01-01

    The measurement of gene expression in postmortem brain is an important tool for understanding the pathogenesis of serious psychiatric disorders. We hypothesized that major molecular deficits associated with psychiatric disease would affect the entire brain, and such deficits may be shared across disorders. We performed RNA sequencing and quantified gene expression in the hippocampus of 100 brains in the Stanley Array Collection followed by replication in the orbitofrontal cortex of 57 brains in the Stanley Neuropathology Consortium. We then identified genes and canonical pathway gene sets with significantly altered expression in schizophrenia and bipolar disorder in the hippocampus and in schizophrenia, bipolar disorder and major depression in the orbitofrontal cortex. Although expression of individual genes varied, gene sets were significantly enriched in both of the brain regions, and many of these were consistent across diagnostic groups. Further examination of core gene sets with consistently increased or decreased expression in both of the brain regions and across target disorders revealed that ribosomal genes are overexpressed while genes involved in neuronal processes, GABAergic signaling, endocytosis and antigen processing have predominantly decreased expression in affected individuals compared to controls without a psychiatric disorder. Our results highlight pathways of central importance to psychiatric health and emphasize messenger RNA processing and protein synthesis as potential therapeutic targets for all three of the disorders. PMID:27622934

  17. Expression of serotonin 5-HT(2A) receptors in the human cerebellum and alterations in schizophrenia.

    PubMed

    Eastwood, S L; Burnet, P W; Gittins, R; Baker, K; Harrison, P J

    2001-11-01

    The occurrence of human cerebellar serotonin 5-HT(2A) receptors (5-HT(2A)R) is equivocal and their status in schizophrenia unknown. Using a range of techniques, we investigated cerebellar 5-HT(2A)R expression in 16 healthy subjects and 16 subjects with schizophrenia. Immunocytochemistry with a monoclonal antibody showed labelling of Purkinje cell bodies and dendrites, as well as putative astrocytes. Western blots showed a major band at approximately 45 kDa. Receptor autoradiography and homogenate binding with [(3)H]ketanserin revealed cerebellar 5-HT(2A)R binding sites present at levels approximately a third of that in prefrontal cortex. 5-HT(2A)R mRNA was detected by reverse transcriptase-polymerase chain reaction, with higher relative levels in men than women. Several aspects of 5-HT(2A)R expression were altered in schizophrenia. 5-HT(2A)R immunoreactivity in Purkinje cells was partially redistributed from soma to dendrites and was increased in white matter. 5-HT(2A)R mRNA was decreased in the male patients. 5-HT(2A)R measured by dot blots and [(3)H]ketanserin binding (B(max) and K(d)) were not significantly altered in schizophrenia. These data show that 5-HT(2A)R gene products (mRNA, protein, binding sites) are expressed in the human cerebellum at nonnegligible levels; this bears upon 5-HT(2A)R imaging studies which use the cerebellum as a reference region. 5-HT(2A)R expression is altered in schizophrenia; the shift of 5-HT(2A)R from soma to dendrites is noteworthy since atypical antipsychotics have the opposite effect. Finally, the results emphasise that expression of a receptor gene is a mutifaceted process. Measurement of multiple parameters is necessary to give a clear picture of the normal situation and to show the profile of alterations in a disease. PMID:11574947

  18. PTEN deficiency promotes macrophage infiltration and hypersensitivity of prostate cancer to IAP antagonist/radiation combination therapy.

    PubMed

    Armstrong, Chris W D; Maxwell, Pamela J; Ong, Chee Wee; Redmond, Kelly M; McCann, Christopher; Neisen, Jessica; Ward, George A; Chessari, Gianni; Johnson, Christopher; Crawford, Nyree T; LaBonte, Melissa J; Prise, Kevin M; Robson, Tracy; Salto-Tellez, Manuel; Longley, Daniel B; Waugh, David J J

    2016-02-16

    PTEN loss is prognostic for patient relapse post-radiotherapy in prostate cancer (CaP). Infiltration of tumor-associated macrophages (TAMs) is associated with reduced disease-free survival following radical prostatectomy. However, the association between PTEN loss, TAM infiltration and radiotherapy response of CaP cells remains to be evaluated. Immunohistochemical and molecular analysis of surgically-resected Gleason 7 tumors confirmed that PTEN loss correlated with increased CXCL8 expression and macrophage infiltration. However PTEN status had no discernable correlation with expression of other inflammatory markers by CaP cells, including TNF-α. In vitro, exposure to conditioned media harvested from irradiated PTEN null CaP cells induced chemotaxis of macrophage-like THP-1 cells, a response partially attenuated by CXCL8 inhibition. Co-culture with THP-1 cells resulted in a modest reduction in the radio-sensitivity of DU145 cells. Cytokine profiling revealed constitutive secretion of TNF-α from CaP cells irrespective of PTEN status and IR-induced TNF-α secretion from THP-1 cells. THP-1-derived TNF-α increased NFκB pro-survival activity and elevated expression of anti-apoptotic proteins including cellular inhibitor of apoptosis protein-1 (cIAP-1) in CaP cells, which could be attenuated by pre-treatment with a TNF-α neutralizing antibody. Treatment with a novel IAP antagonist, AT-IAP, decreased basal and TNF-α-induced cIAP-1 expression in CaP cells, switched TNF-α signaling from pro-survival to pro-apoptotic and increased radiation sensitivity of CaP cells in co-culture with THP-1 cells. We conclude that targeting cIAP-1 can overcome apoptosis resistance of CaP cells and is an ideal approach to exploit high TNF-α signals within the TAM-rich microenvironment of PTEN-deficient CaP cells to enhance response to radiotherapy.

  19. PTEN deficiency promotes macrophage infiltration and hypersensitivity of prostate cancer to IAP antagonist/radiation combination therapy

    PubMed Central

    Armstrong, Chris W.D.; Maxwell, Pamela J.; Ong, Chee Wee; Redmond, Kelly M.; McCann, Christopher; Neisen, Jessica; Ward, George A.; Chessari, Gianni; Johnson, Christopher; Crawford, Nyree T.; LaBonte, Melissa J.; Prise, Kevin M.; Robson, Tracy; Salto-Tellez, Manuel; Longley, Daniel B.; Waugh, David J.J.

    2016-01-01

    PTEN loss is p