School of Public Health, China Medical University, No. 77 Puhe Road, Shenbei New District, Shenyang, Liaoning, P. R. China110122.
Metallomics. 2018 Nov 14;10(11):1607-1617. doi: 10.1039/c8mt00251g.
Chronic exposure to high levels of arsenic has been associated with high risks for many cancers, including renal cell carcinoma (RCC). However the underlying mechanisms are not clear. In the present study, chronic arsenite exposure (2 μM or 5 μM, 30 weeks) induced malignant transformation of HK-2 human renal epithelial cells as indicated by elevated colony formation (6.2- and 5.4-fold increase, respectively), secreted MMP-9 activity (10.1- and 11.3-fold increase, respectively) and proliferation rate (1.2- and 1.3-fold increase in 72 h, respectively). Lipid accumulation, typical of clear cell RCC, was observed in arsenic-transformed (As-TM) cells. Overexpression of hypoxia-inducible factor 2α (HIF2α) and suppression of carnitine palmitoyltransferase 1A (CPT1A) were found at the level of mRNA (1.5- and 0.49-fold of control, respectively) and protein (4.0- and 0.28-fold of control, respectively) after exposure to 2 μM arsenite for 20 weeks. Silencing of HIF2α significantly attenuated arsenite-induced malignant phenotypes and lipid accumulation. Inactivation of Von Hippel-Lindau (VHL) and impaired protein degradation of HIF2α were not found in As-TM cells. Expression of miR-182-5p and miR-802 in As-TM cells was 42.4% and 54.0% of control, respectively (p < 0.05). The levels of mRNA and protein of HIF2α were increased 2.4 folds and 1.6 folds of negative control in response to the miR-182-5p inhibitor, respectively, but decreased to 58.1% and 50.1% of negative control in response to miR-182-5p mimics, respectively. No significant alteration was observed in HIF2α expression when miR-802 was silenced. Our data provide further evidence for the carcinogenic role of arsenic in the kidney. Moreover, the miR-182-5p/HIF2α pathway is indicated to be involved in malignant transformation of human renal epithelial cells under arsenite exposure.
慢性暴露于高水平砷与许多癌症（包括肾细胞癌）的高风险有关。然而，其潜在机制尚不清楚。在本研究中，慢性亚砷酸盐暴露（2 μM 或 5 μM，30 周）诱导 HK-2 人肾小管上皮细胞发生恶性转化，表现为集落形成率升高（分别增加 6.2 倍和 5.4 倍）、分泌的 MMP-9 活性升高（分别增加 10.1 倍和 11.3 倍）和增殖率升高（72 小时分别增加 1.2 倍和 1.3 倍）。砷转化（As-TM）细胞中观察到典型的透明细胞肾细胞癌的脂质积累。在暴露于 2 μM 亚砷酸盐 20 周后，发现缺氧诱导因子 2α（HIF2α）的 mRNA（分别为对照的 1.5 倍和 0.49 倍）和蛋白（分别为对照的 4.0 倍和 0.28 倍）表达过度，肉碱棕榈酰转移酶 1A（CPT1A）表达受到抑制。沉默 HIF2α 可显著减弱亚砷酸盐诱导的恶性表型和脂质积累。在 As-TM 细胞中未发现 Von Hippel-Lindau（VHL）失活和 HIF2α 蛋白降解受损。As-TM 细胞中 miR-182-5p 和 miR-802 的表达分别为对照的 42.4%和 54.0%（p<0.05）。miR-182-5p 抑制剂使 HIF2α 的 mRNA 和蛋白水平分别增加 2.4 倍和 1.6 倍，而 miR-182-5p 模拟物使 HIF2α 的水平分别降低至阴性对照的 58.1%和 50.1%。沉默 miR-802 时，HIF2α 的表达没有明显改变。我们的数据为砷在肾脏中的致癌作用提供了进一步的证据。此外，miR-182-5p/HIF2α 通路表明在亚砷酸盐暴露下参与人肾小管上皮细胞的恶性转化。
