人支气管上皮细胞恶性转化中凋亡敏感性及bcl-2的变化

Alteration of apoptotic susceptibility and bcl-2 gene in malignant transformation of human bronchial epithelial cells

目的：揭示细胞凋亡敏感性在人癌细胞体外恶性转化动态过程中的变化。方法：用已获部分恶 性的ＳＶ４０Ｔ转染的人支气管上皮细胞系Ｍ为材料，通过凋亡ＴＤＴ原位标记、染色体ＦＩＳＨ、ＲＮＡ及蛋白检测等技 术，研究同一株细胞恶性转化过程中凋亡及ｂｃｌ－２、Ｐ５３基因的变化。结果：恶性转化的Ｍ后代细胞较未转化的 Ｍ前代细胞对顺铂诱发细胞凋亡现象不敏感；ｂｃｌ－２基因的转录和表达在Ｍ后代细胞明显高于Ｍ前代细胞，而 且在皿细胞恶性转化进程中呈积累现象；Ｐ５３蛋白在Ｍ前、后代细胞均表达。结论：ｂｃｌ－２过表达使细胞对凋亡 敏感性下降在人支气管上皮细胞恶性转化中起重要作用；Ｐ５３蛋白的灭活不是此ＳＶ４０Ｔ转染细胞恶性转化进程 中ｂｃｌ－２表达积累的主要原因。

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.