Dong Tenghui, Zhang Meiying, Dong Yan, Herman James G, van Engeland Manon, Zhong Guanglin, Guo Mingzhou
Department of Gastroenterology and Hepatology, Chinese PLA General Hospital, Beijing 100853, China.
Medical College of NanKai University, Tianjin 300071, China.
Discov Med. 2015 Nov;20(111):261-71.
Breast cancer is a leading cause of death among females worldwide. However, the mechanisms of breast cancer remain largely unclear. RASSF10 is frequently methylated in certain types of human cancers. To understand the mechanism of RASSF10 in breast cancer, samples of breast cancer cell lines, primary cancer, breast tissue adjacent to cancer, and normal breast tissue were investigated in this study. Methylation specific PCR (MSP), flow cytometry, western blot, and siRNA knockdown assay were used. Complete methylation was found in MCF7, MDA-MB-435, and MDA-MB-468 cells, partial methylation was found in ZR75-1 cells, and unmethylation was revealed in SKBR3 cells. Loss of RASSF10 expression was found in MCF7, MDA-MB-435, and MDA-MB-468 cells, and high expression of RASSF10 was found in ZR75-1 and SKBR3 cells. The expression of RASSF10 was induced by 5-aza-2'-deoxycytidine (5-Aza) in MCF7, MDA-MB-435, and MDA-MB-468 cells. RASSF10 methylation was found in 77.8% (49/63) of primary breast cancer and 17.8% (8/45) of adjacent tissue samples. No methylation was found in normal breast tissue samples. Restoration of RASSF10 expression inhibited cell proliferation and induced G2/M phase arrest in MCF7 and MDA-MB-468 cells. RASSF10 sensitized these cells to docetaxel. RASSF10 induced apoptosis and activated P53 signaling in breast cancer cells. In conclusion, RASSF10 is frequently methylated in human breast cancer and infrequently in adjacent tissue samples. RASSF10 methylation may serve as an early detective marker. The expression of RASSF10 is regulated by promoter region methylation. Since restoration of RASSF10 expression sensitized breast cancer cells to docetaxel, RASSF10 methylation is a potential docetaxel resistant marker. RASSF10 suppresses breast cancer growth by activating P53 signaling.
乳腺癌是全球女性死亡的主要原因之一。然而，乳腺癌的发病机制在很大程度上仍不清楚。RASSF10在某些类型的人类癌症中经常发生甲基化。为了了解RASSF10在乳腺癌中的作用机制，本研究对乳腺癌细胞系、原发性癌、癌旁乳腺组织和正常乳腺组织样本进行了研究。采用甲基化特异性PCR（MSP）、流式细胞术、蛋白质免疫印迹法和小干扰RNA敲低实验。结果发现，MCF7、MDA-MB-435和MDA-MB-468细胞中存在完全甲基化，ZR75-1细胞中存在部分甲基化，SKBR3细胞中未发现甲基化。MCF7、MDA-MB-435和MDA-MB-468细胞中发现RASSF10表达缺失，ZR75-1和SKBR3细胞中发现RASSF10高表达。5-氮杂-2'-脱氧胞苷（5-aza）可诱导MCF7、MDA-MB-435和MDA-MB-468细胞中RASSF10的表达。原发性乳腺癌样本中77.8%（49/63）和癌旁组织样本中17.8%（8/45）发现RASSF10甲基化。正常乳腺组织样本中未发现甲基化。RASSF10表达的恢复抑制了MCF7和MDA-MB-468细胞的增殖并诱导了G2/M期阻滞。RASSF10使这些细胞对多西他赛敏感。RASSF10诱导乳腺癌细胞凋亡并激活P53信号通路。总之，RASSF10在人类乳腺癌中经常发生甲基化，而在癌旁组织样本中较少发生。RASSF10甲基化可能作为一种早期检测标志物。RASSF10的表达受启动子区域甲基化的调控。由于RASSF10表达的恢复使乳腺癌细胞对多西他赛敏感，RASSF10甲基化是一种潜在的多西他赛耐药标志物。RASSF10通过激活P53信号通路抑制乳腺癌生长。
