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Aim: The BRCA1 promoter is hypermethylated in ovarian cancer patients. We postulated that this hypermethylation might be involved in ovarian cancer progression. Methods: To confirm our hypothesis, tissue and serum samples were collected from ovarian carcinoma patients and categorized according to tumor stage. Healthy or benign ovarian disease tissue samples and corresponding serum samples were used as controls. Breast and ovarian cancer susceptibility gene 1 (BRCA1) promoter methylation levels were detected by real-time polymerase chain reaction (PCR). Real-time PCR was also used to evaluate BRCA1 gene expression, and Western blot was performed to assay the expression of BRCA1 protein. Results: BRCA1 showed hypomethylation in 30 normal ovarian and 30 benign ovarian tumors, but showed hypermethylation or methylation in ovarian cancer patients. There was also a significant difference in the BRCA1 promoter methylation levels between different ovarian cancer stages. Compared to stage I and the control groups, there were higher BRCA1 promoter methylation frequencies in stage II and III ovarian cancers. BRCA1 methylation correlated with the loss of BRCA1 expression. BRCA1 promoter in stage I tumors showed hypomethylated. Conclusion: Promoter hypermethylation may act as a biomarker for sporadic ovarian cancer progression, but is unlikely to be helpful in the early diagnosis of ovarian cancer. [ABSTRACT FROM AUTHOR]

Methylation is an important silencing mechanism of breast and ovarian cancer susceptibility gene 1 ( BRCA1) expression in sporadic ovarian cancer. However, the role of BRCA1 methylation in chemotherapy in sporadic ovarian cancer and the related pathways have not been understood completely. This study has determined the roles of BRCA1 hypermethylation in chemotherapy of sporadic ovarian cancer and its related signaling pathways. We used bisulfite sequencing, real-time polymerase chain reaction, and western blotting to check the methylation state and expression levels of BRCA1 of the following cell lines: platinum-sensitive human ovarian cancer cell line COC1, platinum-resistant cell line COC1/DDP, SKOV-3, and 5-Aza-dC treated COC1. The cisplatin sensitivity of ovarian cancer cells was examined by MTS (methyl-thiazol tetrazolium) assay. Tumorigenicity in vivo and DDP-based chemosensitivity were compared among the above cells. Phosphatidylinositol 3′-kinase (PI3K)–Akt pathway activation in ovarian cancer cells was studied by western blotting. The frequency of BRCA1 methylation in the COC1 cell line was higher than in COC1/DDP and SKOV-3 cell lines, whereas the mRNA and protein expression of BRCA1 were lower than in the COC1/DDP and SKOV-3 cell lines. DNA demethylation decreased the chemosensitivity of COC1 cells and partially increased the expression levels of BRCA1. The activation of the PI3K-Akt pathway was low in ovarian cancer cells. Our results indicate that hypermethylation of BRCA1 might play an important role in the chemosensitivity of ovarian cancer, and that the PI3K–Akt pathway is not involved in this response. ( Cancer Sci 2010) [ABSTRACT FROM AUTHOR]

The regulatory mechanism of endometrial carcinoma and the signal transduction pathways involved in hormone action are poorly defined. It has become apparent that the G protein-coupled receptor (GPR) 30 mediates the non-genomic signaling of 17β-estradiol (E2). Here we show that GPR30 is highly expressed in endometrial cancer tissues and cancer cell lines and positively regulates cell proliferation and invasion. GPR30 expression was detected in 50 human endometrial carcinomas. The transcription level of GPR30 was significantly higher in the tissue of endometrial carcinoma than in normal endometrium ( P < 0.05). Immunohistochemical assays revealed that the positive expression rate of GPR30 protein in endometrial carcinoma tissue (35/50, 70%) was statistically higher than in normal endometrium tissue (8/30, 26.67%) (χ2 = 14.16, P = 0.0002). GPR30 overexpression was correlated with high-grade endometrial carcinoma. GPR30 expression was also found in two human endometrial cancer cell lines: RL95-2 (estrogen receptor positive) and KLE (estrogen receptor negative). The roles of GPR30 in proliferative and invasive responses to E2 and G1, a non-steroidal GPR30-specific agonist, in RL95-2 and KLE cell lines were then explored. We showed that E2 and G1 could initiate the MAPK/ERK mitogen-activated protein kinase pathway in both cell lines. What's more, E2 and G1 promoted KLE and RL95-2 proliferation and stimulated matrix metalloproteinase production and activity via the GPR30-mediated MEK/ERK mitogen-activated protein kinase pathway, as well as increased interleukin-6 secretion. These findings suggest that GPR30-mediated non-genomic signaling could play an important role in endometrial cancer. ( Cancer Sci 2009; 100: 1051–1061) [ABSTRACT FROM AUTHOR]