Department of Food Bioscience, College of Biomedical & Health Science, Konkuk University, Chungju 27478, Korea.
Department of Biomedical Chemistry, College of Biomedical & Health Science, Konkuk University, Chungju 27478, Korea.
Int J Mol Sci. 2019 Mar 3;20(5):1092. doi: 10.3390/ijms20051092.
Several reports have shown that thymoquinone (TQ) effectively attenuates angiogenesis in cancer cells, resulting in suppression of tumor growth. However, it is not yet clear whether TQ reduces hypoxia-inducible factor-1α (HIF-1α) expression in hypoxic cancer cells. Here, we found that TQ was a novel HIF-1α inhibitor through hypoxia response element (HRE)-luciferase assay-based large screening by using 502 natural compounds containing chemical library. TQ reduced HIF-1α protein levels in renal cancer cells; however, it did not affect the HIF-1α protein levels in the presence of proteasome inhibitor, MG132, indicating that the reduction effects of TQ on HIF-1α protein are mediated via the ubiquitination-proteasome dependent pathway. TQ boosted HIF-1α protein degradation, and the mechanism was revealed by inhibiting interaction between HSP90 and HIF-1α. TQ suppressed downstream genes of HIF-1α, indicating negative impact of TQ on HIF-1α transcriptional activities. In addition, TQ altered glucose, lactate, and ATP levels, leading to anaerobic metabolic disturbance. TQ induced apoptosis in hypoxic cancer cells as determined by crystal violet staining and flow cytometry for annexin V-stained cells. Taken together, we suggested that TQ is a potential anticancer agent targeting HIF-1α.
已有多项报告表明，百里醌（TQ）可有效抑制癌细胞的血管生成，从而抑制肿瘤生长。然而，TQ 是否能降低低氧癌细胞中缺氧诱导因子-1α（HIF-1α）的表达尚不清楚。在这里，我们通过基于缺氧反应元件（HRE）-荧光素酶检测的大型筛选，发现 TQ 是一种新型的 HIF-1α 抑制剂，该筛选使用了包含化学文库的 502 种天然化合物。TQ 降低了肾癌细胞中的 HIF-1α 蛋白水平；然而，当存在蛋白酶体抑制剂 MG132 时，它并不影响 HIF-1α 蛋白水平，这表明 TQ 对 HIF-1α 蛋白的降低作用是通过泛素化-蛋白酶体依赖途径介导的。TQ 促进了 HIF-1α 蛋白的降解，其机制是通过抑制 HSP90 与 HIF-1α 之间的相互作用来揭示的。TQ 抑制了 HIF-1α 的下游基因，表明 TQ 对 HIF-1α 转录活性有负面影响。此外，TQ 改变了葡萄糖、乳酸和 ATP 水平，导致无氧代谢紊乱。TQ 通过结晶紫染色和流式细胞术检测 Annexin V 染色细胞来诱导缺氧癌细胞凋亡。总之，我们认为 TQ 是一种潜在的靶向 HIF-1α 的抗癌药物。
