Capsaicin Targets tNOX (ENOX2) to Inhibit G1 Cyclin/CDK Complex, as Assessed by the Cellular Thermal Shift Assay (CETSA)
Capsaicin Targets tNOX (ENOX2) to Inhibit G1 Cyclin/CDK Complex, as Assessed by the Cellular Thermal Shift Assay (CETSA)
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DOI：
10.3390/cells8101275
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发表时间：
2019-10-01
期刊：
影响因子：
6
通讯作者：
Lin, Ming-Hung
中科院分区：
文献类型：
--
作者：
Islam, Atikul;Su, Ally J.;Lin, Ming-Hung
辣椒素（8-甲基-N-香草基-6-壬酰胺）是红辣椒中的活性成分，被用作化学预防剂，对癌细胞显示出良好的细胞毒性。越来越多的证据表明，辣椒素优先抑制肿瘤相关的NADH氧化酶（tNOX，ENOX 2），这是普遍表达的癌症，但不是在非转化细胞。这通过诱导细胞凋亡来减弱癌细胞生长。辣椒素介导的tNOX抑制最近显示出延长细胞周期。然而，这种调节的分子事件尚未被调查。在本研究中，我们使用了细胞热位移试验（CETSA）来检测辣椒素的“目标接合”及其对细胞周期进程的影响。我们的研究结果表明，辣椒素与tNOX结合并触发tNOX的蛋白酶体降解，从而导致NAD（+）依赖性SIRT 1脱乙酰酶的抑制。最终，c-Myc和p53的乙酰化水平增强，这抑制了G1期细胞周期蛋白/细胞周期蛋白依赖性激酶复合物的激活，并触发癌细胞的细胞周期停滞。当tNOX在非癌细胞中过表达时获得的结果验证了其在细胞周期进程中的重要性。这些发现为tNOX的调节作用和辣椒素在调节膀胱癌细胞的细胞周期中的抗增殖特性提供了第一个分子见解。
Capsaicin (8-methyl-N-vanillyl-6-noneamide), which is an active component in red chili peppers, is used as a chemopreventive agent that shows favorable cytotoxicity against cancer cells. Accumulating evidence indicates that capsaicin preferentially inhibits a tumor-associated NADH oxidase (tNOX, ENOX2) that is ubiquitously expressed in cancer but not in non-transformed cells. This attenuates cancer cell growth by inducing apoptosis. The capsaicin-mediated inhibition of tNOX was recently shown to prolong the cell cycle. However, the molecular events underlying this regulation have not yet been investigated. In the present study, we used a cellular thermal shift assay (CETSA) to detect "target engagement" of capsaicin and its consequent impact on cell cycle progression. Our results indicated that capsaicin engaged with tNOX and triggered the proteasomal degradation of tNOX, which leads to the inhibition of NAD(+)-dependent SIRT1 deacetylase. Ultimately, the acetylation levels of c-Myc and p53 were enhanced, which suppressed the activation of G1 cyclin/Cyclin-dependent kinase complexes and triggered cell cycle arrest in cancer cells. The results obtained when tNOX was overexpressed in non-cancer cells validated its importance in cell cycle progression. These findings provide the first molecular insights into the regulatory role of tNOX and the anti-proliferative property of capsaicin in regulating the cell cycle of bladder cancer cells.