Yeh Yao-Tsung, Yeh Hua, Su Shu-Hui, Lin Jian-Sheng, Lee Kuo-Jui, Shyu Huey-Wen, Chen Zi-Feng, Huang Sheng-Yun, Su Shu-Jem
Department of Medical Laboratory Sciences and Biotechnology, School of Medicine and Health Sciences, Fooyin University, Kaohsiung City 83102, Taiwan.
Institute of Medical Sciences, College of Medicine, Tzu Chi University, Hualien, Taiwan.
Free Radic Biol Med. 2014 Sep;74:1-13. doi: 10.1016/j.freeradbiomed.2014.06.008. Epub 2014 Jun 19.
Phenethyl isothiocyanate (PEITC) is a naturally occurring cruciferous vegetable-derived compound that inhibits cell growth and induces apoptosis in oral cancer cells. However, the exact mechanism of PEITC action has not been fully elucidated. This study investigated the molecular mechanism and anticancer potential of PEITC in oral squamous cell carcinoma (OSCC) cells with various p53 statuses. PEITC inhibited the growth of OC2, SCC4, and SCC25 cells (functional p53 mutants) in a dose-dependent manner with low toxicity to normal cells. Treatment with PEITC induced reactive oxygen species production, nitric oxide generation, and GSH depletion and triggered DNA damage response as evidenced by flow cytometry, 8-OHdG formation, and comet assay. Furthermore, the subsequent activation of ATM, Chk2, and p53 as well as the increased expression of downstream proteins p21 and Bax resulted in a G2/M phase arrest by inhibiting Cdc25C, Cdc2, and cyclin B1. The PEITC-induced apoptotic cell death, following a diminished mitochondrial transmembrane potential, reduced the expression of Bcl-2 and Mcl-1, released mitochondrial cytochrome c, and activated caspase 3 and PARP cleavage. The p53 inhibitor pifithrin-α and the antioxidants N-acetylcysteine and glutathione (GSH) protected the cells from PEITC-mediated apoptosis. However, mito-TEMPO, catalase, apocynin, and L-NAME did not prevent PEITC-induced cell death, suggesting that PEITC induced G2/M phase arrest and apoptosis in oral cancer cells via a GSH redox stress and oxidative DNA damage-induced ATM-Chk2-p53-related pathway. These results provide new insights into the critical roles of both GSH redox stress and p53 in the regulation of PEITC-induced G2/M cell cycle arrest and apoptosis in OSCCs.
异硫氰酸苯乙酯（PEITC）是一种天然存在的源自十字花科蔬菜的化合物，可抑制口腔癌细胞的生长并诱导其凋亡。然而，PEITC作用的确切机制尚未完全阐明。本研究调查了PEITC在具有不同p53状态的口腔鳞状细胞癌（OSCC）细胞中的分子机制和抗癌潜力。PEITC以剂量依赖性方式抑制OC2、SCC4和SCC25细胞（功能性p53突变体）的生长，对正常细胞毒性较低。PEITC处理可诱导活性氧生成、一氧化氮产生和谷胱甘肽（GSH）消耗，并引发DNA损伤反应，流式细胞术、8-羟基脱氧鸟苷（8-OHdG）形成和彗星试验证明了这一点。此外，随后ATM、Chk2和p53的激活以及下游蛋白p21和Bax表达的增加，通过抑制细胞周期蛋白磷酸酶25C（Cdc25C）、细胞周期蛋白依赖性激酶2（Cdc2）和细胞周期蛋白B1导致G2/M期阻滞。PEITC诱导的凋亡细胞死亡，在线粒体跨膜电位降低后，降低了Bcl-2和髓细胞白血病-1（Mcl-1）的表达，释放了线粒体细胞色素c，并激活了半胱天冬酶3（caspase 3）和聚（ADP-核糖）聚合酶（PARP）裂解。p53抑制剂pifithrin-α以及抗氧化剂N-乙酰半胱氨酸和谷胱甘肽（GSH）可保护细胞免受PEITC介导的凋亡。然而，线粒体靶向抗氧化剂Mito-TEMPO、过氧化氢酶、阿朴吗啡和L-硝基精氨酸甲酯（L-NAME）并不能阻止PEITC诱导的细胞死亡，这表明PEITC通过GSH氧化还原应激和氧化DNA损伤诱导的ATM-Chk2-p53相关途径诱导口腔癌细胞的G2/M期阻滞和凋亡。这些结果为GSH氧化还原应激和p53在调节PEITC诱导的OSCCs中G2/M细胞周期阻滞和凋亡的关键作用提供了新的见解。
