Reprimo对H460非小细胞肺癌细胞的放射增敏作用及机制研究
首发时间:2019-01-09
摘要:Reprimo(RPRM)是从受到X射线照射后的小鼠成纤维细胞中被首次分离发现。目前认为,RPRM作为一个受DNA损伤诱导激活并依赖p53的抑癌基因,通过引发细胞周期阻滞、抑制细胞增殖和迁移、促进细胞凋亡等多重机制参与调控细胞生长和肿瘤细胞迁移。越来越多的研究表明,在包括胃癌、结直肠癌、乳腺癌和垂体腺瘤等众多癌症中,由于RPRM启动子的高度甲基化,导致其在肿瘤组织中低表达甚至缺失,从而促进肿瘤细胞的增殖和迁移。然而,其发生机制尚不清楚。本例研究发现高表达RPRM的肿瘤细胞其放射敏感性显著增加,具体表现在肿瘤细胞克隆形成率降低。与此同时,高表达RPRM的肿瘤细胞受照后DNA双链断裂更严重且修复能力下降,提示RPRM参与调控DNA损伤修复通路。进一步研究发现,高表达RPRM的细胞受照后其ATM蛋白表达水平明显降低,受其影响,磷酸化的ATM以及其下游的γ-H2AX、RAD51、p53等DNA损伤修复相关蛋白表达水平也显著降低。综上所述,RPRM通过抑制DNA损伤修复通路最上游的ATM的活性进而抑制DNA损伤修复通路的激活,从而增加肿瘤细胞的放射敏感性。
关键词: RPRM DNA损伤应答反应 放射敏感性 非小细胞肺癌细胞 ATM
For information in English, please click here
A novel role of Reprimo in the radiosensitivity of H460 non-small-cell lung cancer cells
Abstract:Reprimo, a gene firstly isolated from X-irradiated cells by Takahashi et al., has been identified as a novel tumor suppressor gene. It has been found that RPRM is involved in the regulation of cell proliferation and migration via mechanisms such as inducing cell cycle arrest, inhibiting cell proliferation and migration, enhancing apoptosis, etc. Moreover, It has been reported that the promoter hypermethylation of Reprimo correlates with its dysfunction in some cancer types such as gastric, colorectal, breast and pituitary cancer, suggesting its role in the initiation, progression and metastasis of cancer. However, the studies on the relevant signaling pathways of RPRM are still very limited. For example, although Reprimo can be induced by DNA damage, and the activation is dependent on p53, it is unclear whether RPRM plays a role in the DNA damage response (DDR) and the radiosensitivity of cancer cells. In this study, we found that when RPRM was overexpressed in H460 cell line, the cells became more sensitive to X-rays, manifest as reduced colony formation and increased micronucleus formation, suggesting an important role of Reprimo in radiosensitivity of non-small-cell lung cancer cells. Furthermore, using comet assay we demonstrated that there was more residue DNA damage in cells overexpressing Reprimo at different times after irradiation, indicating that RPRM overexpression promoted IR-induced DNA damage and inhibited the DNA damage repair in irradiated cells. In addition, ATM phosphorylation was found to be inhibited in RPRM overexpressed H460 cells, for which the reduced expression of ATM might be responsible. In consistent with the inhibition of ATM activation, the down-stream DDR related protein such as Rad51, γ-H2AX and p53 etc. were also suppressed in response to X-irradiation in RPRM overexpressed H460 cells. These data suggested that RPRM might play an important inhibitory role in DDR via down-regulating ATM. In summary, our results revealed a novel role of RPRM in the radiosensitivity and DDR in non-small-cell lung cancer cells, which involved its novel down-regulatory effect on ATM.
Keywords: RPRM DNA damage response Radiosensitivity NSCLC ATM
引用
No.****
动态公开评议
共计0人参与
勘误表
Reprimo对H460非小细胞肺癌细胞的放射增敏作用及机制研究
评论
全部评论0/1000