氯化镉诱发16HBE细胞系恶性转化过程中TIF3 p36的变化

Expression change of TIF3 p36 at different stages of human bronchial epithelial cells transformed and induced by cadmium chloride

目的探讨氯化镉诱发人支气管上皮细胞(16HBE)恶性转化过程中不同阶段蛋白翻译起始因子(TIF3)p36mRNA表达水平的变化,为进一步阐明氯化镉的分子致癌机制提供线索。方法应用逆转录-聚合酶链式反应(RT-PCR)技术,以及敏感先进的Taqman荧光定量PCR方法,检测并分析氯化镉诱发16HBE恶性转化不同阶段即转化期间细胞、转化细胞和成瘤细胞的TIF3 p36 mRNA表达量的变化。结果相对于非转化对照细胞(16HBE),氯化镉诱发恶性转化不同阶段细胞(转化期间细胞、转化细胞和成瘤细胞)的TIF3 p36 mRNA基因表达水平均明显升高(P＜0．01或P＜0．05),其中低剂量组(5μmol/L)所转化的各阶段细胞的eIF3 p36 mRNA平均表达量分别是对照细胞的3．1、5．9和9．9倍,中剂量组(10μmol/L)的各阶段转化细胞的TIF3平均表达量分别是对照细胞的7．1、6．8和14．8倍,高剂量组(15μmol/L)的各阶段转化细胞的TIF3 p36平均表达量分别是对照细胞的3．6、3．0和9．1倍。这些不同剂量组的研究结果提示,eIF3 p36的异常表达量与氯化镉诱发16HBE细胞恶变程度之间有正相关关系,但与镉的剂量无关。结论氯化镉在诱发16HBE细胞恶变过程中,存在明显的蛋白翻译启动因子eIF3 p36异常表达现象,其表达水平与细胞的恶变程度密切相关,这可能是氯化镉诱发人细胞肿瘤的重要分子致癌机制之一。

Objective To explore the molecular mechanisms potentially responsible for carcinogenesis due to cadmium by detecting expression change of the translation initiation factor 3（TIF3 p36） in those malignant transformation of human bronchial epithelial cell lines（16HBE） induced by cadmium chloride（CdCl2）. Methods The expression changes of TIF3 p36 were detected and analyzed at different stages of malignant cells（semi transformed cells, transformed cells and tumorigenic cells） induced by CdCl2 solution with both reverse transcription PCR technique and sensitive fluorescent quantitative PCR assay. Results Compared with non-transformed human bronchial epithelial cells, the results of fluorescent quantitative PCR assay showed that the semi-transformed cells, transformed cells and tumorigenic cells all expressed higher levels of TIF3 p36 mRNA（ P 〈 0.01 or P 〈 0.05 ）. As compared with the control cells, the TIF3 expressions at different stages of malignant transformation were 3.1 times, 5.9 times and 9.9 times higher respectively in the low dosage group of CdCl2 （5 μmol/L）;7.1 times, 6.8 times and 14.8 times respectively in the middle dosage group of CdCl2（10 μmol/L）;3.6 times,3.0 times and 9. 1 times respectively in high of dose of CdCl2（ 15 μmol/L）.These results showed that there was the positive correlation between overexpression levels of TIF3 p36 mRNA and the malignant degree of the cells, but they were not related to the dosages of cadmium. Conclusion There is significantly abnormal overexpression of TIF3 gene during malignant transformation of human bronchial epithelial cell line induced by cadmium chloride, and the TIF3 expression is associated with the malignant degree of the cells, which may be one of molecular mechanisms potentially responsible for the carcinogenesis due to cadmium.