卵巢亮細胞癌中腫瘤抑制基因SFRP基因啟動子甲基化之分析

Analysis of the methylation status of the SFRP genes in ovarian clear cell carcinoma

蘇立欣(Li-Hsin Su)

指導教授 ： 張淑芬

臺北醫學大學/醫學院/醫學科學研究所/碩士(2009年)

摘要

腫瘤抑制基因啟動子高度甲基化是造成基因不正常表現的機制之一。SFRPs (secreted frizzled-related proteins) 是細胞外的分子能拮抗Wnt訊息傳遞。本研究針對在台灣發生率佔卵巢癌12%的卵巢亮細胞癌探討SFRP基因群啟動子甲基化的情形以了解此種癌症形成的分子機制。結果顯示SFRP5基因啟動子甲基化在卵巢亮細胞癌檢體中的比例為42% (5/12) ，在卵巢亮細胞癌細胞株的比例為100% (5/5) ，但於良性卵巢囊腫檢體的比例為0% (0/15) ，漿液性卵巢癌檢體的比例為20% (3/15) 。而SFRP1啟動子只有在40% (2/5) 的卵巢亮細胞癌細胞株呈現甲基化的情形，於卵巢亮細胞癌檢體、良性卵巢囊腫檢體及漿液性卵巢癌檢體SFRP1啟動子都是沒有甲基化。以正常淋巴球細胞中的SFRP5表現量為基準，在測試的卵巢亮細胞癌細胞株中有80% (4/5) 有SFRP5的表現。且以去甲基藥物5’-aza-2’-deoxycytidine (5-aza-dC) 處理十五天後，SFRP5的mRNA在卵巢亮細胞癌細胞株中有60% (3/5) 會上升。SFRP1在卵巢亮細胞癌細胞株有40% (2/5) 是沒有表現，但在去甲基藥物處理十五天後，SFRP1的表現量並無差異。此外，實驗結果也顯示加入去甲基藥物，可以抑制卵巢亮細胞癌細胞株的生長速度 (cell proliferation) 及移行能力 (migration) 。

關鍵字

卵巢亮細胞癌 ； SFRP5 ； 細胞生長速度 ； 細胞移行

並列摘要

Tumor suppressor genes are known to be inactivated by epigenetic modifications including promoter methylation. Secreted frizzled-related proteins (SFRPs) are extracellular signaling molecules that antagonize the Wnt signaling pathway. Ovarian clear cell carcinoma constitutes 12% of surface epithelial ovarian cancer in Taiwan. However, the role of SFRP genes in ovarian clear cell carcinoma molecular mechanism remains unknown. We investigated the SFRP1 and SFRP5 promoter status and demonstrated that SFRP5 gene promoter was methylated in 42% (5/12) ovarian clear cell carcinoma tissues and in 100% (5/5) ovarian clear cell carcinoma cell lines, compared with 0% (0/15) benign ovarian cyst and 20% (3/15) serous ovarian carcinoma tissues. And the SFRP1 gene promoter methylated only in 40% (2/5) ovarian clear cell carcinoma cell lines. Our results show that endogenous SFRP5 mRNA expression can be detected in four (80%) of the five ovarian clear cell carcinoma cell lines and is higher than that detected in normal lymphocytes. Treatment with the demethylating agent 5-aza-2'- deoxycytidine for 15 days rescued SFRP5 mRNA expression (60%, 3/5). Endogeous SFRP1 mRNA expression is absent in two (40%) of the five ovarian clear cell carcinoma cell lines. But treatment with the demethylating agent did not rescue SFRP1 mRNA expression nor restore SFRP1 promoter methylation atatus. We also find that suppressed ovarian cell carcinoma cell growth and migration ability.

並列關鍵字

ovarian clear cell carcinoma ； SFRP5 ； cell proliferation ； migration

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