Department of Zoology, West Bengal State University, Berunanpukuria, Malikapur, North-24 Parganas, Barasat, Kolkata 700126, West Bengal, India.
Department of Biophysics, Bose Institute, Centenary Campus P 1/12, C. I. T. Road, Scheme - VII (M) Kolkata 700054, West Bengal, India.
Chem Biol Interact. 2018 Apr 1;285:59-68. doi: 10.1016/j.cbi.2018.02.030. Epub 2018 Feb 24.
Cancer cells possess elevated ROS coupled with increased levels of antioxidant enzymes which render them resistant against cytotoxic chemotherapies. Therefore, an understanding of the interaction between key molecules involved in stress adaptive mechanisms is important to innovate strategies against cancer cell chemoresistance. Here, the lung adenocarcinoma cell line A549 with constitutively expressed Nrf2 was found to be more tolerant to HO (0.1, 0.2, 0.5 and 1 mM) than normal lung cell line L132 or p53 null lung cancer cell line H1299. Maximum cytoprotection was observed at 0.2 mM HO accompanied by a significant increase in p21, Nrf2 and antioxidant enzymes in A549 cells. The increased p21 expression was independent of p53 but dependent on Nrf2 as evident from qPCR, Western blotting and dual luciferase assays after silencing Nrf-2 and p53 genes. Highly conserved Nrf-2 binding sites were identified in p21 promoter by bioinformatics and homology modeling which was further confirmed by ChIP and reporter assay.
癌细胞具有高水平的 ROS 和抗氧化酶，这使它们对细胞毒性化疗药物具有抗性。因此，了解参与应激适应机制的关键分子之间的相互作用对于创新抗癌药物的耐药性策略非常重要。在这里，发现具有持续表达 Nrf2 的肺腺癌细胞系 A549 比正常肺细胞系 L132 或 p53 缺失肺癌细胞系 H1299 对 HO（0.1、0.2、0.5 和 1 mM）更耐受。在 0.2 mM HO 时观察到最大的细胞保护作用，同时 A549 细胞中的 p21、Nrf2 和抗氧化酶显著增加。增加的 p21 表达不依赖于 p53，但依赖于 Nrf2，这从沉默 Nrf-2 和 p53 基因后的 qPCR、Western blot 和双荧光素酶测定中可以明显看出。通过生物信息学和同源建模鉴定了 p21 启动子中的高度保守的 Nrf-2 结合位点，并通过 ChIP 和报告基因测定进一步证实了这一点。
