褪黑素通过促凋亡协同增强顺铂对人喉癌细胞增殖的抑制作用

Melatonin synergistically enhances cisplatin-induced cell proliferation suppression of Hep-2 human laryngeal cancer cells by promoting apoptosis

目的:研究褪黑素(melatonin,MT)对人喉癌细胞增殖与凋亡的影响及MT增强人喉癌细胞对顺铂(cisplatin,DDP)治疗的敏感性。方法:采用不同质量浓度MT和DDP单独或联合处理Hep-2细胞;通过CCK-8法检测细胞增殖,流式细胞术检测细胞凋亡和细胞周期,采用两药相互作用指数(co-efficient of drug interaction,CDI)评估MT是否影响Hep-2细胞对DDP的敏感性。结果:CCK-8检测结果显示,单用MT或DDP可浓度依赖性抑制Hep-2细胞的增殖,MT可协同增强DDP对Hep-2细胞的增殖抑制作用(CDI<1)。流式细胞术检测细胞凋亡和细胞周期结果显示,MT可促进Hep-2细胞凋亡以及增加亚G1期细胞比例(P<0.01),MT可协同DDP促进Hep-2细胞凋亡[0.5 mmol/L MT联合20μg/ml DDP组的细胞凋亡率显著高于20μg/ml DDP组,(40.9±3.0)%vs(11.0±0.9)%,P<0.01]以及亚G1期细胞比例[0.5 mmol/L MT联合20μg/ml DDP组的亚G1期细胞比例显著高于20μg/ml DDP组,(73.0±2.4)%vs(40.4±3.0)%,P<0.01]。加入Caspase抑制剂Z-VAD-fmk可逆转MT和/或DDP对Hep-2细胞的增殖抑制作用和凋亡诱导作用(均P<0.01)。结论:MT能以Caspase依赖的方式诱导人喉癌细胞Hep-2的凋亡,从而协同增强DDP对细胞的增殖抑制作用。

Objective：Toinvestigate the effect of melatonin （MT） on humanlaryngeal cancercells and its ability to enhance the sensitivity of humanlaryngeal cancercells tocisplatin （DDP） treatment, this study was performed. Methods： Hep 2 human laryngeal cancer cells were treated with various concentrations of MT and/or DDP in vitro for various times. Then cells proliferation was detected by CCK 8 assays and cell apoptosis or cell cycle was assayed by flow cytometry. The co efficient of drug interaction （CDI） was used to evaluate whether MT could affect the sensitivity of Hep 2 cells to DDP. Results：It was demonstrated by CCK 8 assays that MT or DDP used alone inhibited the proliferation of Hep 2 cells in a dose dependent manner.Combined treatment with MT and DDP synergistically inhibited the proliferation of Hep 2 cells with the synergism between two drugs （CDI〈1）. Furthermore,flow cytometry results showed that MT promoted apoptotic cells and the proportion of cells in sub G1 phase in Hep 2 cells, and co treatment with MT and DDP increased apoptotic cells （the apoptotic rate of cells in the 0.5 mmol/L MT and 20 μg/ml DDP combination group was significantly higher than that in 20 μg/ml DDP group, ／[40.9±3.0／]% vs ／[11.0±09／]%, P〈0.01） and the proportion of cells in sub G1 phase （the proportion of cells in sub G1 phase in the 0.5 mmol/L MT and 20 μg/ml DDP combination group was significantly higher than that in 20 μg/ml DDP group, ／[73.0±2.4／]% vs ／[40.4±3.0／]%, P〈0.01）. Caspase inhibitor Z VAD fmk reversed the suppression of Hep 2 cell proliferation and the induction of Hep 2 cell apoptosis by MT and/or DDP （both P〈0.01）. Conclusions：Our findings demonstrate that melatonin can induce Hep 2 human laryngeal cancer cell apoptosis in caspase dependent manners, thereby synergistically enhancing the suppressive effects of cisplatin on human laryngealcancercellproliferation.