METHODS: Gastric cancer cells MKN45 were cultured under 1% oxygen hypoxia and conventional air conditions. An intervention group with the addition of the chemotherapeutic drug 5-FU was also established. The proliferation and apoptosis of gastric cancer cells under different oxygen conditions and intervention groups were detected using the cell counting kit-8 (CCK-8) method, JC-1 mitochondrial membrane potential assay, and Annexin-V/PI double staining method. Cell cycle changes were detected by flow cytometry, and mitochondrial changes were detected using electron microscopy.
RESULTS: In the absence of 5-FU intervention, compared with the normoxia group, the hypoxia group showed higher rates of early and late apoptosis and higher cell death rates as indicated by the JC-1 mitochondrial membrane potential assay, Annexin-V/PI double staining, and CCK-8 results. Flow cytometry results showed that the cell cycle was arrested in the G0/G1 phase without progression. Electron microscopy revealed more severe mitochondrial destruction. However, with 5-FU intervention, the hypoxia group showed lower apoptosis rates, more cell cycle progression, and less mitochondrial destruction compared with the normoxia group.
CONCLUSIONS: Hypoxic environments promote apoptosis and even death in gastric cancer cells, but hypoxia counteracts the efficacy of the chemotherapeutic drug 5-FU, which may contribute to 5-FU chemotherapy resistance.
目的: 缺氧是造成胃癌化学治疗(以下简称“化疗”)耐药的重要原因,但目前对单纯缺氧环境下胃癌的生长情况了解甚少,本研究通过观察缺氧对胃癌细胞生长的影响,探讨缺氧环境中胃癌细胞对化疗药物5-氟尿嘧啶(5-fluorouracil,5-FU)的反应。方法: 设置缺氧(1%氧气)及常规空气环境,将胃癌细胞MKN45分别置于上述环境中培养,同时设立化疗药物5-FU干预组。采用细胞计数试剂盒-8(cell counting kit-8,CCK-8)法、JC-1线粒体膜电位法及Annexin-V/PI双染法检测不同氧含量环境中、不同干预组胃癌细胞的增殖及凋亡情况,流式细胞术检测细胞周期的改变,在电镜下观察细胞线粒体变化情况。结果: 不加5-FU干预的情况下,缺氧组与常氧组相比,JC-1线粒体膜电位法、Annexin-V/PI双染法及CCK-8检测结果显示胃癌细胞早期凋亡、晚期凋亡率更高,细胞死亡率更高;流式细胞术检测结果显示细胞周期被阻止在G0/G1期,不进展;电镜结果显示线粒体破坏更严重。而在加入5-FU干预的情况下,缺氧组与常氧组相比,凋亡率低,细胞周期更易进展,线粒体破坏更少。结论: 缺氧环境促进胃癌细胞凋亡甚至死亡,但是缺氧环境对化疗药物5-FU的起效产生反作用,可能是造成5-FU化疗耐药的因素。.