1 Department of Urology, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, People's Republic of China.
2 Second Department of Internal Medicine, Cancer Hospital of Jiangxi Province, Nanchang, Jiangxi 330029, People's Republic of China.
Exp Biol Med (Maywood). 2017 Jun;242(12):1299-1305. doi: 10.1177/1535370217701625. Epub 2017 Apr 21.
Renal cell carcinoma (RCC) is a malignant tumor, which severely threatens human's life, moreover, the multi-drug resistance (MDR) under RCC undoubtedly strengthen the difficulties in the treatment. MiR-451 has been considered to play an important role in regulation of MDR in several cancers, but the role of it in MDR of RCC has not been explored. This study aims to explore the mechanism of miR-451 as a target to regulate chemotherapy resistance, which is crucial for further exploring novel therapy for RCC. Two human cell lines (ACHN and GRC-1) were performed in this study and adriamycin (ADM) was used to construct MDR cell lines. qRT-PCR was used to determine the mRNA expression of miR-451 and ATF-2. Weston blot was used to determine protein expression. MTT assay and flow cytometry were used for assessing cell viability and apoptosis, individually. Luciferase reporter assay was used to detect the targeting of miR-451 and ATF-2. Results presented that the expression of miR-451 was higher in low MDR cell line (ACHN) comparing with the high MDR cell line (GRC-1), while the expression of ATF-2 revealed an opposite results. MiR-451 targeted ATF-2 and regulated its expression. Overexpression of miR-451 strengthened drug resistance, decreased cell viability, and increased cell apoptosis of GRC-1 pretreated by ADM, while overexpressed ATF-2 reversed the effect induced by miR-451 overexpression. Then miR-451 knockdown improved drug susceptibility, decreased cell apoptosis, and increased cell viability of ACHN induced by ADM, however, ATF-2 suppression reversed the low rate of cell apoptosis and high rate of cell viability induced by miR-451 knockdown. Our results revealed that miR-451 regulates the drug resistance of RCC by targeting ATF-2 gene, which might be critical for overcoming MDR in RCC patients. Impact statement This is the first study to emphasize the expression of miR-451 on regulating multi-drug resistance (MDR) in renal cell carcinoma (RCC). Our study found that miR-451 regulates the drug resistance of RCC by targeting ATF-2, which might be critical for overcoming MDR in RCC patients. This study not only provides solid theory foundation for the clinical therapy, but also offers unique insights for the further RCC research. Furthermore, the study helps us to understand the mechanism of MDR, which was crucial for identifying the chemoresistance on several related tumors.
肾细胞癌 (RCC) 是一种恶性肿瘤，严重威胁着人类的生命，此外，RCC 中的多药耐药性 (MDR) 无疑增加了治疗的难度。miR-451 已被认为在几种癌症的 MDR 调节中发挥重要作用，但它在 RCC 的 MDR 中的作用尚未得到探索。本研究旨在探讨 miR-451 作为调节化疗耐药性的靶点的机制，这对于进一步探索 RCC 的新疗法至关重要。本研究使用两种人类细胞系 (ACHN 和 GRC-1) 并使用阿霉素 (ADM) 构建 MDR 细胞系。qRT-PCR 用于确定 miR-451 和 ATF-2 的 mRNA 表达。Western blot 用于确定蛋白表达。MTT 测定和流式细胞术分别用于评估细胞活力和细胞凋亡。荧光素酶报告基因检测用于检测 miR-451 和 ATF-2 的靶向关系。结果表明，低 MDR 细胞系 (ACHN) 中 miR-451 的表达高于高 MDR 细胞系 (GRC-1)，而 ATF-2 的表达则呈现相反的结果。miR-451 靶向 ATF-2 并调节其表达。过表达 miR-451 可增强 GRC-1 预先用 ADM 处理后的药物耐药性、降低细胞活力并增加细胞凋亡，而过表达 ATF-2 则逆转了 miR-451 过表达引起的作用。然后，miR-451 敲低可提高 ACHN 诱导的 ADM 敏感性、降低细胞凋亡并增加细胞活力，然而，ATF-2 抑制逆转了 miR-451 敲低诱导的低细胞凋亡率和高细胞活力率。我们的结果表明，miR-451 通过靶向 ATF-2 基因调节 RCC 的药物耐药性，这对于克服 RCC 患者的 MDR 可能至关重要。
