Department of Respiratory Medicine, The First Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou 450000, China.
Department of Internal Medicine-Oncology, The First Affiliated Hospital, Zhengzhou University, China.
Biochem Biophys Res Commun. 2014 Feb 21;444(4):611-6. doi: 10.1016/j.bbrc.2014.01.103. Epub 2014 Jan 31.
It is reported that MicroRNA-503 (miR-503) regulates cell apoptosis, and thus modulates the resistance of non-small cell lung cancer cells (NSCLC) to cisplatin. However, the exact role of miR-503 in NSCLC remains unknown. In the present study, the level of miR-503 expression in NSCLC was evaluated using realtime PCR, and the DNA methylation status within miR-503 promoter was analyzed by Combined Bisulfite Restriction Analysis (COBRA) or bisulfite-treated DNA sequencing assays (BSP). We found that the expression of miR-503 was significantly decreased in NSCLC tissues compared to normal tissues. A statistically significant inverse association was found between miR-503 methylation status and expression of the miR-503 in tumor tissues (P<0.001), and expression of miR-503 was restored by the demethylating agent 5-aza-2'-deoxycytidine, suggesting that methylation was associated with the transcriptional silencing. Then, we show that miR-503 targets a homologous DNA region in the 3'-UTR region of the Fanconi anemia complementation group A protein (FANCA) gene and represses its expression at the transcriptional level. Taken together, our results suggest that miR-503 regulates the resistance of non-small cell lung cancer cells to cisplatin at least in part by targeting FANCA.
据报道，MicroRNA-503（miR-503）可调节细胞凋亡，从而调节非小细胞肺癌细胞（NSCLC）对顺铂的耐药性。然而，miR-503 在 NSCLC 中的确切作用尚不清楚。在本研究中，通过实时 PCR 评估 NSCLC 中 miR-503 的表达水平，并通过联合亚硫酸氢盐限制性分析（COBRA）或亚硫酸氢盐处理的 DNA 测序分析（BSP）分析 miR-503 启动子内的 DNA 甲基化状态。我们发现 miR-503 在 NSCLC 组织中的表达明显低于正常组织。miR-503 甲基化状态与肿瘤组织中 miR-503 的表达呈统计学显著负相关（P<0.001），并且去甲基化剂 5-aza-2'-脱氧胞苷可恢复 miR-503 的表达，表明甲基化与转录沉默有关。然后，我们表明 miR-503 靶向 Fanconi 贫血互补组 A 蛋白（FANCA）基因 3'-UTR 区域中的同源 DNA 区域，并在转录水平上抑制其表达。总之，我们的结果表明，miR-503 通过靶向 FANCA 至少部分调节非小细胞肺癌细胞对顺铂的耐药性。
