Department of Healthcare Administration, College of Medical and Health Science, Asia University, Taichung, Taiwan; School of Dentistry, College of Dentistry, China Medical University, Taichung, Taiwan.
Division of Oral Diagnosis and Family Dentistry, School of Dentistry, National Defense Medical Center, Taipei, Taiwan; School of Dentistry, College of Dentistry, China Medical University, Taichung, Taiwan.
J Formos Med Assoc. 2021 Jan;120(1 Pt 3):668-678. doi: 10.1016/j.jfma.2020.07.037. Epub 2020 Aug 13.
BACKGROUND/PURPOSE: Arecoline, the major alkaloid of areca nut, is known to induce reactive oxygen species (ROS) and DNA damage during oral cancer progression. This study aim to evaluate whether melatonin, an antioxidant, supported or repressed the arecoline-induced carcinogenesis phenotypes in oral squamous cell carcinoma (OSCC).
The cytotoxicity of arecoline or melatonin treatment alone and their co-treatment in the OSCC cell line OEC-M1 were analyzed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The cell cycle, cell death, and total ROS production were analyzed using flow cytometer. The protein expression was determined using western blot analysis. The genotoxicity and mutation rate were determined using micronucleus assay and hypoxanthine phosphoribosyl transferase (HPRT) forward mutation assay, respectively, in CHO-K1 cells. The ataxia telangiectasia mutated (ATM) promoter activity and DNA repair ability were determined through reporter assay.
The result showed that both the arecoline and melatonin induced ROS production and antioxidant enzymes expression. Melatonin treatment enhanced arecoline-induced ROS production, cytotoxicity, G2/M phase arrest, and cell apoptosis in OSCC cells. On the other hand, melatonin treatment activated DNA repair activity to reverse arecoline-induced DNA damage and mutation.
These results indicated that melatonin is a potential chemopreventive agent for betel quid chewers to prevent OSCC initiation and progression.
背景/目的：已知槟榔中的主要生物碱槟榔碱在口腔癌进展过程中会诱导活性氧（ROS）和 DNA 损伤。本研究旨在评估抗氧化剂褪黑素是否支持或抑制槟榔碱诱导的口腔鳞状细胞癌（OSCC）致癌表型。
使用 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐（MTT）测定法分析槟榔碱或褪黑素单独处理以及它们在 OSCC 细胞系 OEC-M1 中的共同处理的细胞毒性。使用流式细胞仪分析细胞周期、细胞死亡和总 ROS 产生。使用 Western blot 分析测定蛋白表达。使用微核试验和次黄嘌呤鸟嘌呤磷酸核糖转移酶（HPRT）正向突变试验分别在 CHO-K1 细胞中测定遗传毒性和突变率。通过报告试验测定共济失调毛细血管扩张突变（ATM）启动子活性和 DNA 修复能力。
结果表明，槟榔碱和褪黑素均诱导 ROS 产生和抗氧化酶表达。褪黑素处理增强了 OSCC 细胞中槟榔碱诱导的 ROS 产生、细胞毒性、G2/M 期阻滞和细胞凋亡。另一方面，褪黑素处理激活了 DNA 修复活性，以逆转槟榔碱诱导的 DNA 损伤和突变。
这些结果表明，褪黑素可能是槟榔咀嚼者预防 OSCC 发生和进展的潜在化学预防剂。
