Role of the polypeptide N-acetylgalactosaminyltransferase 3 in ovarian cancer progression: possible implications in abnormal mucin O-glycosylation
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE52602 | GEO | 2014/05/22
SECONDARY ACCESSION(S): PRJNA229460
REPOSITORIES: GEO
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Project description:Previously, we have identified the polypeptide N-acetylgalactosaminyltransferase 3 (GALNT3) gene as notably hypomethylated in low-malignant potential (LMP) and high-grade (HG) serous epithelial ovarian tumors, compared to normal ovarian tissues. Here we show that GALNT3 is strongly overexpressed in both LMP and HG serous EOC tumors, thus suggesting that epigenetic mechanisms might be implicated in GALNT3 overexpression in serous epithelial ovarian cancer (EOC). Moreover, GALNT3 expression significantly correlated with shorter progression-free survival (PFS) periods in serous EOC patients with advanced disease. Knockdown of the GALNT3 expression in EOC cells led to sharp decrease of cell proliferation and induced S-phase cell cycle arrest. Additionally, GALNT3 suppression significantly inhibited EOC cell migration and invasion. Gene expression profiling and consecutive network and pathway analyses confirmed these findings, as numerous genes and pathways known previously to be implicated in ovarian tumorigenesis, including EOC tumor invasion and metastasis, were found to be downregulated upon GALNT3 suppression, while some tumor suppressor genes were induced. Moreover, GALNT3 downregulation was associated with reduced MUC1 protein expression in EOC cells, probably related to destabilization of the MUC1 protein due to lack of GALNT3 glycosylation activity.Taken together, our data are indicative for a strong oncogenic potential of the GALNT3 gene in advanced EOC and identify this transferase as a novel EOC biomarker and putative EOC therapeutic target. Our findings also suggest that GALNT3 overexpression might contribute to ovarian etiology through aberrant mucin O-glycosylation. To better understand the molecular mechanisms of GALNT3 gene action in ovarian cancer cells, we employed the Agilent Whole Human Genome microarrays, containing ~ 44,000 genes to identify global gene expression changes upon GALNT3 suppression in A2780s cells. We compared the gene expression of the previously selected clone shRNA- GALNT3-knockdown clones 1 & 2 (sh-cl1 & sh-cl2) against the corresponding control (ctrl) clone. The microarray experiments were performed in duplicates, as four hybridizations were carried out for the GALNT3-suppressing cell clones against the corresponding control, using a fluorescent dye reversal (dye-swap) technique.
2014-05-22 | E-GEOD-52602 | biostudies-arrayexpress
Project description:Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy, thus understanding molecular changes associated with EOC progression could lead to the identification of essential therapeutic targets. Glycosylation is a post-translational modification (PTM) that participates in major pathophysiology events, including tumorigenesis. Aberrant mucin-type or O-glycosylation in cancer is frequently attributed to altered expression of different N-acetylgalactosaminyltransferases (GalNAc-Ts). We have previously identified the N-acetylgalactosaminyltransferase 3 (GALNT3) gene as a potential EOC oncogene, possibly implicated in aberrant O-glycosylation in EOC cells. Literature reports are suggestive for genetic and functional redundancy between different GalNAc-Ts, and our previous data were indicative for an induction of the GALNT6 expression upon GALNT3 suppression in EOC cells. Here we show that GALNT3 gene knockout (KO) in the A2780s EOC cells leads to strong GALNT6 upregulation. Moreover, A2780s cell migration, invasion, proliferation and cell cycle analysis were significantly reduced in double GALNT3/T6 gene KO cells compared to single GALNT3 gene KO. Furthermore, MUC1 expression was downregulated in both GALNT3 KO and GALNT3/6 KO, with a more prominent decrease observed in the double KO clone. In vivo studies supported the observed functional redundancy imposed by GALNT6, as animals injected with double GALNT3/T6 KO EOC cell clones displayed a significant increase in survival rates compared to those injected with the control and the GALNT3 KO clones. Collectively our data strongly suggest for possible functional redundancy of the two GalNAc-Ts (GALNT3 and T6) in EOC, with the perspective to use both of these genes as EOC markers and/or therapeutic targets.
2019-05-07 | GSE104861 | GEO
Project description:Previously, we have identified cytosolic form of the branched chain amino-acid transaminase 1 (BCAT1) as notably hypomethylated in low-malignant potential (LMP) and high-grade (HG) serous epithelial ovarian tumors, compared to normal ovarian tissues. Here we show that BCAT1 is strongly overexpressed in both LMP and HG serous EOC tumors, thus suggesting that epigenetic mechanisms might be implicated in BCAT1 overexpression in serous epithelial ovarian cancer (EOC). Knockdown of the BCAT1 expression in EOC cells led to sharp decrease of cell proliferation and induced S-phase cell cycle arrest. Additionally, BCAT1 suppression significantly inhibited EOC cell migration and invasion. Gene expression profiling and consecutive network and pathway analyses confirmed these findings, as numerous genes and pathways known previously to be implicated in ovarian tumorigenesis, including EOC tumor invasion and metastasis, were found to be downregulated upon BCAT1 suppression, while some tumor suppressor genes were induced. Taken together, our data are indicative for a strong oncogenic potential of the BCAT1 gene in advanced EOC and identify this transaminase as a novel EOC biomarker and putative EOC therapeutic target.
2015-10-01 | GSE64424 | GEO
Project description:Previously, we have identified cytosolic form of the grainyhead transcription factor 2 gene (GRHL2) as notably hypomethylated in low-malignant potential (LMP) and high-grade (HG) serous epithelial ovarian tumors, compared to normal ovarian tissues. Here we show that GRHL2 is strongly overexpressed in both LMP and HG serous EOC tumors, thus suggesting that epigenetic mechanisms might be implicated in GRHL2 overexpression in serous epithelial ovarian cancer (EOC). Knockdown of the GRHL2 expression in EOC cells led to sharp decrease of cell proliferation and induced G1-phase cell cycle arrest. Additionally, GRHL2 suppression significantly inhibited EOC cell migration and invasion. Gene expression profiling and consecutive network and pathway analyses confirmed these findings, as numerous genes and pathways known previously to be implicated in ovarian tumorigenesis, including EOC tumor invasion and metastasis, were found to be downregulated upon BCAT1 suppression, while some tumor suppressor genes were induced. Taken together, our data are indicative for a strong oncogenic potential of the GRHL2 gene in advanced EOC and identify this transaminase as a novel EOC biomarker and putative EOC therapeutic target.
2017-04-21 | GSE90132 | GEO
Project description:Low-grade serous ovarian carcinoma is believed to arise from serous borderline ovarian tumors, yet the progression from serous borderline tumors to low-grade serous ovarian carcinoma remains poorly understood. The purpose of this study was to identify differentially expressed genes between the two groups. Expression profiles were generated from 6 human ovarian surface epithelia (HOSE), 8 serous borderline ovarian tumors (SBOT), 13 low-grade serous ovarian carcinomas (LG), and 22 high-grade serous ovarian carcinomas (HG). The anterior gradient homolog 3 (AGR3) gene was found to be highly upregulated in serous borderline ovarian tumors; this finding was validated by real-time quantitative RT-PCR, Western blotting, and immunohistochemistry. Anti-AGR3 immunohistochemistry was performed on an additional 56 LG and 103 HG tissues and the results were correlated with clinical data. Expression profiling determined that 1254 genes were differentially expressed (P < 0.005) between SBOT, LG and HG tumors. Serous borderline ovarian tumors exhibited robust positive staining for AGR3, with a lower percentage of tumor cells stained in LG and HG. Immunofluorescence staining indicated that AGR3 expression was limited to ciliated cells. Tumor samples with a high percentage (>10%) of AGR3 positively stained tumor cells were associated with improved longer median survival in both the LG (P = 0.013) and HG (P = 0.008) serous ovarian carcinoma groups. The progression of serous borderline ovarian tumors to low-grade serous ovarian carcinoma may involve the de-differentiation of ciliated cells. AGR3 could serve as a prognostic marker for survival in patients with low-grade and high-grade serous ovarian carcinomas. Total RNA were extracted from microdissected human ovarian surface epithelia (HOSE, n=6), and microdissected serous borderline ovarian tumors (LMP, n=8), low-grade serous ovarian carcinomas (LGOSC, n=13), and 22 high-grade serous ovarian carcinomas (HGOSC, n=22). Gene Expression profiles were then generated with commercial GeneChip Human Genome U133 Plus 2.0 Array. dChip was used to identify significant differentially expressed genes between LMP/LGOSC and HGOSC
2011-03-04 | E-GEOD-27651 | biostudies-arrayexpress
Project description:Epithelial ovarian cancer (EOC) accounts for 4% of all cancers in women and is the leading cause of death from gynecologic malignancies. It is well established that cancer invasion and metastasis still represent the major causes of the failure of cancer treatment. Previously, we identified the mannose receptor LY75 (DEC205/CD205) gene as notably hypomethylated in high-grade (HG) serous epithelial ovarian tumors, compared to normal ovarian tissues. LY75 has been identified as a putative antigen-uptake receptor, which is expressed abundantly on dendritic cells, which are specialist antigen presenting cells to T lymphocytes for the initiation of an immune response. The implication of LY75 in EOC tumorigenesis is currently unknown. Here we show that LY75 is strongly overexpressed in HG serous EOC tumors as compared to normal ovarian tissue. Importantly, shRNA-mediated LY75 knockout in the mesenchymal EOC cells (SKOV3) led to mesenchymal to epithelial transition (MET), associated with overexpression of epithelial markers E-cadherin and EPCAM and loss of expression of mesenchymal markers Fibronectin, N-cadherin Snail1 and Twist1. In addition, LY75 suppression significantly inhibited EOC cell migration and invasion in vitro. However, LY75 knockdown led to enhanced tumor cell dissemination and significantly increased lethality in vivo, in xenograft model of advanced peritoneal EOC. Thus, our findings indicate that LY75 could play an essential role in the mesenchymal-to-epithelial transition (MET) of EOC cells and support the hypothesis that, while epithelial-to-mesenchymal transition (EMT) enables the invasiveness of tumor cells, a MET-associated epithelial phenotype could be essential for their metastatic colonization.
2016-04-01 | GSE74711 | GEO
Project description:Epithelial ovarian cancer (EOC) accounts for 4% of all cancers in women and is the leading cause of death from gynecologic malignancies. It is well established that cancer invasion and metastasis still represent the major causes of the failure of cancer treatment. Previously, we identified the mannose receptor LY75 (DEC205/CD205) gene as notably hypomethylated in high-grade (HG) serous epithelial ovarian tumors, compared to normal ovarian tissues. LY75 has been identified as a putative antigen-uptake receptor, which is expressed abundantly on dendritic cells, which are specialist antigen presenting cells to T lymphocytes for the initiation of an immune response. The implication of LY75 in EOC tumorigenesis is currently unknown. Here we show that LY75 is strongly overexpressed in HG serous EOC tumors as compared to normal ovarian tissue. Importantly, shRNA-mediated LY75 knockout in the mesenchymal EOC cells (SKOV3) led to mesenchymal to epithelial transition (MET), associated with overexpression of epithelial markers E-cadherin and EPCAM and loss of expression of mesenchymal markers Fibronectin, N-cadherin Snail1 and Twist1. In addition, LY75 suppression significantly inhibited EOC cell migration and invasion in vitro. However, LY75 knockdown led to enhanced tumor cell dissemination and significantly increased lethality in vivo, in xenograft model of advanced peritoneal EOC. Thus, our findings indicate that LY75 could play an essential role in the mesenchymal-to-epithelial transition (MET) of EOC cells and support the hypothesis that, while epithelial-to-mesenchymal transition (EMT) enables the invasiveness of tumor cells, a MET-associated epithelial phenotype could be essential for their metastatic colonization. To better understand the molecular mechanisms of LY75 gene action in epithelial ovarian cancer (EOC), we employed the Agilent Whole Human Genome microarrays, containing ~ 44,000 genes to identify global gene expression changes upon LY75 suppression in SKOV3 EOC cells. We compared the gene expression of the previously selected shRNA-mediated LY75-knockdown clones sh-S3 and sh-S6 against the corresponding control (ctrl) clone. The microarray experiments were performed in duplicates, as two hybridizations were carried out for each of the LY75-suppressing cell clone against the corresponding control, using a fluorescent dye reversal (dye-swap) technique.
2016-04-01 | E-GEOD-74711 | biostudies-arrayexpress
Project description:Objective: Ovarian tumors of low-malignant potential (LMP) and low-grade serous ovarian carcinomas are thought to represent different stages on a tumorigenic continuum and to develop along pathways distinct from that of high-grade serous ovarian carcinoma. Past studies have utilized gene expression profiles to support this theory. The objective of the current study was to identify new genes whose expression profiles in LMP ovarian tumors and low-grade ovarian carcinomas differ from that in high-grade ovarian carcinomas. Methods: We used RNA from 3 normal human ovarian surface epithelia (HOSE) and from 10 low-grade and 10 high-grade serous ovarian carcinoma samples to perform gene expression profiling. Using real-time reverse-transcription polymerase chain reaction (RT-PCR), we evaluated changes in PAX2 mRNA expression in cDNA created from RNA extracted from an independent set of ovarian tissue samples (7 LMP tumors and 17 low-grade and 23 high-grade serous carcinomas). We also examined PAX2 expression using Western blot analysis of protein extracted from a set of ovarian LMP and low- and high-grade carcinoma tissue samples. Additionally, we used immunohistochemistry (IHC) to validate PAX2 overexpression in a third independent set of paraffin ovarian tissue sections from 17 LMP tumors and 16 low- and 257 high-grade carcinomas. Results: Gene profiling revealed higher expression of PAX2 in low-grade than in high-grade ovarian carcinomas. Real-time RT-PCR demonstrated a statistically significant difference in median PAX2 mRNA expression, expressed as fold change, among ovarian LMP tumor (1837.38), low-grade (183.12), and high-grade (3.72) carcinoma samples (p=0.015). Western blot analysis revealed strong PAX2 expression in ovarian LMP and low-grade carcinoma samples but no PAX2 protein expression in high-grade carcinomas. On IHC, more LMP tumor and low-grade carcinoma samples expressed moderate to high levels of PAX2 than did high-grade ovarian carcinoma samples. The numbers of samples with strong nuclear staining was significantly higher for ovarian LMP tumors (10 of 17, p<0.001) and low-grade serous carcinomas (10 of 16, p<0.001) than for high-grade carcinomas (27 of 257). Discussion: Our identification and validation of higher PAX2 expression in ovarian LMP tumors and low-grade serous carcinomas than in high-grade carcinomas supports the two-tiered hypothesis that the first two are on a continuum and are distinct from high-grade ovarian carcinomas. PAX2 may represent a potential biomarker and future therapeutic target for individualizing chemotherapy for ovarian LMP tumors and low-grade carcinomas in the future. Experiment Overall Design: We used RNA from 3 normal human ovarian surface epithelia (HOSE) and from 10 low-grade and 10 high-grade serous ovarian carcinoma samples to perform gene expression profiling. Using real-time reverse-transcription polymerase chain reaction (RT-PCR), we evaluated changes in PAX2 mRNA expression in cDNA created from RNA extracted from an independent set of ovarian tissue samples (7 LMP tumors and 17 low-grade and 23 high-grade serous carcinomas). We also examined PAX2 expression using Western blot analysis of protein extracted from a set of ovarian LMP and low- and high-grade carcinoma tissue samples. Additionally, we used immunohistochemistry (IHC) to validate PAX2 overexpression in a third independent set of paraffin ovarian tissue sections from 17 LMP tumors and 16 low- and 257 high-grade carcinomas.
2009-06-08 | E-GEOD-14001 | biostudies-arrayexpress
Project description:Objective: Ovarian tumors of low-malignant potential (LMP) and low-grade serous ovarian carcinomas are thought to represent different stages on a tumorigenic continuum and to develop along pathways distinct from that of high-grade serous ovarian carcinoma. Past studies have utilized gene expression profiles to support this theory. The objective of the current study was to identify new genes whose expression profiles in LMP ovarian tumors and low-grade ovarian carcinomas differ from that in high-grade ovarian carcinomas. Methods: We used RNA from 3 normal human ovarian surface epithelia (HOSE) and from 10 low-grade and 10 high-grade serous ovarian carcinoma samples to perform gene expression profiling. Using real-time reverse-transcription polymerase chain reaction (RT-PCR), we evaluated changes in PAX2 mRNA expression in cDNA created from RNA extracted from an independent set of ovarian tissue samples (7 LMP tumors and 17 low-grade and 23 high-grade serous carcinomas). We also examined PAX2 expression using Western blot analysis of protein extracted from a set of ovarian LMP and low- and high-grade carcinoma tissue samples. Additionally, we used immunohistochemistry (IHC) to validate PAX2 overexpression in a third independent set of paraffin ovarian tissue sections from 17 LMP tumors and 16 low- and 257 high-grade carcinomas. Results: Gene profiling revealed higher expression of PAX2 in low-grade than in high-grade ovarian carcinomas. Real-time RT-PCR demonstrated a statistically significant difference in median PAX2 mRNA expression, expressed as fold change, among ovarian LMP tumor (1837.38), low-grade (183.12), and high-grade (3.72) carcinoma samples (p=0.015). Western blot analysis revealed strong PAX2 expression in ovarian LMP and low-grade carcinoma samples but no PAX2 protein expression in high-grade carcinomas. On IHC, more LMP tumor and low-grade carcinoma samples expressed moderate to high levels of PAX2 than did high-grade ovarian carcinoma samples. The numbers of samples with strong nuclear staining was significantly higher for ovarian LMP tumors (10 of 17, p<0.001) and low-grade serous carcinomas (10 of 16, p<0.001) than for high-grade carcinomas (27 of 257). Discussion: Our identification and validation of higher PAX2 expression in ovarian LMP tumors and low-grade serous carcinomas than in high-grade carcinomas supports the two-tiered hypothesis that the first two are on a continuum and are distinct from high-grade ovarian carcinomas. PAX2 may represent a potential biomarker and future therapeutic target for individualizing chemotherapy for ovarian LMP tumors and low-grade carcinomas in the future.
2009-05-31 | GSE14001 | GEO
Project description:We profile expression in serous epithelial ovarian carcinomas to assess the possibility of an miRNA signature associated with chemoresistance. Resistance to the available therapies is one of the main causes of low survival of patients with advanced epithelial ovarian cancer, thus representing an emergency in oncology. Here, we profiled miRNA expression in 86 naïve serous epithelial ovarian carcinomas (EOCs) to assess the possibility of miRNAs associated with chemoresistance. We identified 23 miRNAs associated with chemoresistance, of which three (miR-484, miR-642 and miR-217) were confirmed in the validation set (112 independent patients). The study of miR-484 role demonstrated that it regulated the chemoresistance of EOC cells acting not on cancer cells but on tumor vasculature. In particular, miR-484 is produced and secreted by chemosensitive EOC, therefore regulating the production of VEGFB by cancer cells and the expression of VEGFR2 in endothelial cells. Overall, we demonstrated that a three-miR signature can classify the response to chemotherapy and that chemoresistance in EOC relays, at least in part, on the control of tumor angiogenesis, indicating new options in the treatment of these patients. We analyzed tumor samples (<5% of normal tissue) from FFPE blocks of 86 patients with serous ovarian carcinomas.
2013-05-17 | E-GEOD-43867 | biostudies-arrayexpress