FasL基因表达对缺氧状态下直肠癌细胞增殖凋亡的影响

目的探讨直肠癌侵袭转移过程中FasL基因表达对细胞增殖凋亡的影响。方法采用北京军区总医院普通外科实验室构建的4组不同侵袭力的人直肠癌HR-8348细胞亚型HR-8348B、HR-8348L、HR-8348F和HR-8348As，并用化学缺氧法构建上述4组细胞的缺氧12h模型，以Western印迹法验证各组细胞内FasL蛋白的表达水平和缺氧状态下细胞内FasL蛋白的表达，流式细胞仪测定细胞周期分布并计算细胞增殖指数，四甲基偶氮唑盐（MTT）法测定细胞增殖能力改变并计算细胞抑制率，末端标记法（TUNEL）测定细胞凋亡状况。结果Western印迹显示FasL蛋白于40000处显色。常氧条件下HR-8348F细胞内FasL的表达水平显著高于HR-8348B、HR-8348L和HR-8348As（F=361.149。P〈0.01）；缺氧12h时各组细胞均生长良好，形态较常氧状态皱缩；HR-834F，细胞内FasL的表达水平仍显著高于其他3组（F=278.766，P〈0.01），但其自身常氧与缺氧状态下FasL的水平差异无统计学意义（t=1.762，P〉0.05）。缺氧12h后各组细胞增殖均受到抑制，HR-8348F细胞的增殖指数（60.43±3.72）显著高于HR-8348B（40.01±3.30）、HR-8348L（41.30±4.06）和HR-8348As（35.87±4.39）（F=39.477，P〈0.01），增殖抑制率（17.30±1.98）和凋亡指数（13.10±1.04）显著低于HR-8348B（33.70±4.33和21.60±1.31）、HR-8348L（34.20±3.92和20.10±1.15）、HR-8348As（38.00±4.55和23.90±1.23）细胞（F分别为28.811和76.462，P〈0.01）。结论缺氧环境中，直肠癌细胞FasL表达增强可导致细胞增殖加速、凋亡减少和侵袭能力增强。促进细胞对微环境缺氧的耐受。

Effect of FasL gene expression on proliferation and apoptosis of rectal carcinoma cells in hypoxia state

Objective To elucidate the effect of FasL gene expression on the proliferation and apoptosis of hypoxic rectal carcinoma cells. Methods The normoxic expression level of FasL in HR-8348 subtype cells (HR-8348B, HR-8348L, HR-8348F and HR-8348As) with different invasive power were verified by Western blot. Hypoxia models for HR-8348B, HR-8348L, HR-8348F and HR-8348As were constructed with chemical modeling, then the FasL levels in all groups at 12 h after hypoxia were quantitated by Western blot. Distribution of different cell life cycles was determined with flow cytometry. Cell reproductive activities were detected with MTT method, and cell apoptesis was assessed with TUNEL. Results FasL protein was pigmentized at the position of 40 000 by Western blot, and the expression level of FasL was significantly higher in HR-8348F cells than those in HR-8348B, HR-8348L and HR-8348As cells(F=361.149, P<0.01) in normoxia. At 12 h after hypoxia, the FasL level was also significantly higher in HR-8348F cells than those in other groups (F=278.766, P<0.01), but was not markedly different as compared to themselves in normoxia (t=1.762, P>0.05). The proliferation index was significantly higher in HR-8348F (60.43±3.72) than those in HR-8348B (40.01±3.30), HR-8348L (41.30±4.06) and HR-8348As cells (35.87±4.39), respectively (F=39.477, P<0.01). However, both inhibition rate of proliferation and apoptotic index were remarkably lower in HR-8348F (17.30±1.98 and 13.10±1.04) than those in HR-834B (33.70±4.33 and 21.60±1.31), HR-8348L (34.20±3.92 and 20.10±1.15), and HR-8348As (38.00±4.55 and 23.90±1.23), respectively (F=28.811 and 76.462, respectively, P<0.01). Conclusion The expression enhancement of intracellular FasL in rectal carcinoma in hypoxia can lead to accelerated proliferation and reduced apeptosis of cells, which will promote tumor cells to adapt microenvironmental hypoxia.