Down-regulation of p16 and MGMT promotes the anti-proliferative and pro-apoptotic effects of 5-Aza-dC and radiation on cervical cancer cells
Down-regulation of p16 and MGMT promotes the anti-proliferative and pro-apoptotic effects of 5-Aza-dC and radiation on cervical cancer cells
复制标题
DOI：
10.1002/cbf.3282
复制
发表时间：
2017-12-01
影响因子：
3.6
通讯作者：
Wu, Yi-long
中科院分区：
文献类型：
--
作者：
Chen, Guan-di;Qian, De-ying;Wu, Yi-long
宫颈癌是女性生殖系统最常见的恶性肿瘤之一。因此，研究宫颈癌发生、发展的分子机制至关重要。在这项研究中，我们用5-aza-2-脱氧胞苷（5-Aza-dC）刺激宫颈癌细胞，发现这种处理抑制细胞增殖并诱导细胞凋亡；此外，p16 和 O-6-甲基鸟嘌呤-DNA 甲基转移酶 (MGMT) 的甲基化被逆转，尽管它们的表达受到抑制。 5-Aza-dC 抑制 E6 和 E7 表达并上调 p53、p21 和 Rb 表达。转染针对p16和MGMT的siRNA的细胞以及用5-Aza-dC刺激的细胞均停滞在S期，并且p53、p21和Rb的表达上调更显着。然而，当细胞转染针对p16和MGMT的siRNA后用5-Aza-dC刺激时，增殖显着下降，并且处于亚G1峰和S期的细胞百分比显着增加，表明细胞凋亡显着增加。但 E6 和 E7 过度表达可以挽救观察到的增殖效应。此外，X射线辐射导致细胞停滞在G2/M期，但用p16和MGMT靶向的siRNA转染后进行X射线辐射的细胞表现出增殖显着下降，并向亚G1峰移动，也表明细胞凋亡增强。此外，当 MGMT 表达下调时，5-Aza-dC 和 X 射线辐射的影响最为明显。因此，p16 和 MGMT 表达的下调增强了 5-Aza-dC 和 X 射线辐射的抗增殖作用。这一发现可能为宫颈癌的治疗提供新思路。
Cervical cancer is one of the most common malignancies of the female reproductive system. Therefore, it is critical to investigate the molecular mechanisms involved in the development and progression of cervical cancer. In this study, we stimulated cervical cancer cells with 5-aza-2-deoxycytidine (5-Aza-dC) and found that this treatment inhibited cell proliferation and induced apoptosis; additionally, methylation of p16 and O-6-methylguanine-DNA methyltransferase (MGMT) was reversed, although their expression was suppressed. 5-Aza-dC inhibited E6 and E7 expression and up-regulated p53, p21, and Rb expression. Cells transfected with siRNAs targeting p16 and MGMT as well as cells stimulated with 5-Aza-dC were arrested in S phase, and the expression of p53, p21, and Rb was up-regulated more significantly. However, when cells were stimulated with 5-Aza-dC after transfection with siRNAs targeting p16 and MGMT, proliferation decreased significantly, and the percentage of cells in the sub-G1 peak and in S phase was significantly increased, suggesting a marked increase in apoptosis. But E6 and E7 overexpression could rescue the observed effects in proliferation. Furthermore, X-ray radiation caused cells to arrest in G2/M phase, but cells transfected with p16- and MGMT-targeted siRNAs followed by X-ray radiation exhibited a significant decrease in proliferation and were shifted toward the sub-G1 peak, also indicating enhanced apoptosis. In addition, the effects of 5-Aza-dC and X-ray radiation were most pronounced when MGMT expression was down-regulated. Therefore, down-regulation of p16 and MGMT expression enhances the anti-proliferative effects of 5-Aza-dC and X-ray radiation. This discovery may provide novel ideas for the treatment of cervical cancer.