Alteration of apoptotic susceptibility and bcl-2 gene in malignant transformation of human bronchial epithelial cells / 中国病理生理杂志

ABSTRACT

AIM: To demonstrate the susceptibility of cell apoptosis varies during the progress of cell malig- nant transformation from human being in vitro. METHODS: A SV40T - transfected human bronchial epithelial im- mortalized cell line (called M) was selected in this work, which has acquired some characteristics of malignant trans- formation at the later passage. The alterations of apoptosis and bcl- 2, P53 genes between early and later passage of M cells were investigated by means of TDT labeling in situ, chromosome FISH, RNA and protein testing, etc. RE- SULTS Incidence of apoptosis induced by cis - platin was significantly lower in later than in early passages of M. Levels of bcl - 2 mRNA and protein in later passages were higher than early passages of M, and overxpression of bcl -2 was accumulated following the development of cellular malignancy. P53 protein level was as high in early as in later passages. CONCLUSION: Overexpression of bcl - 2 decreases the cellular sensitivity to apoptotic inductors plays an important role during progress of carcinogenesis in human bronchial epithelial cancers. The inactivation of P53 protein in the SV40 - T transfected M cell line may be one of reasons of bcl - 2 overexpression, but not associated with the accumulation of bcl - 2 expressed level during cell transformation.