OBJECTIVETo 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 (CdCl(2)).

METHODSThe 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 CdCl(2) solution with both reverse transcription PCR technique and sensitive fluorescent quantitative PCR assay.

RESULTSCompared 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 CdCl(2) (5 micromol/L); 7.1 times, 6.8 times and 14.8 times respectively in the middle dosage group of CdCl(2) (10 micromol/L); 3.6 times, 3.0 times and 9.1 times respectively in high of dose of CdCl(2) (15 micromol/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.

CONCLUSIONThere 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.