tetracycline and Carcinoma--Giant-Cell

To establish a tetracycline-regulated expression model and to determine and verify whether a specific point mutant type p53 minigene, containing an Arg-->Leu substitution at amino acid 172, possesses a suppressing effect on human lung cancer.. The tumor suppressing effects of inducing apoptosis and inhibition of the formation of G418 resistant colonies of the specific point mutated p53 minigene in a structural expression vector on a human cancer cell line PG with preexisting dominant negative p53 were preliminarily verified. Then the specific p53 minigene was sub-cloned into a tetracycline-transactivative controlled expression vector pBPSTR1 by gene recombination methods. Through LipofectaMINE, the vector was transfected into PG cells under the presence of tetracycline (1.0 mg/ml), and the transfectants were screened in the selecting medium containing 1.5 micrograms/ml puromycin, the p53 minigene expression and tumor suppressing effects were studied dynamically in presence/absence (1.0/0 mg/ml) of tetracycline.. The specific mutant p53 minigenes had a stronger tumor suppressing effect than wild type p53 minigene on colony formation and transient expression could induce PG cell apoptosis (P < 0.05). The tetracycline transactivative p53 minigene-regulated transgene model was successfully established. When tetracycline was absent, a large amount of apoptosis cells in transgenic passage colonies could be detected. Therefore the tumor suppressing effects were further verified.. The specific point mutant p53 minigene may be a good candidate for cancer gene therapy. The tetracycline transactivative response promoter was found to be a good regulator of down stream gene expression, this may be useful in future gene therapy.

Topics: Animals; Apoptosis; Carcinoma, Giant Cell; Gene Expression Regulation, Neoplastic; Genes, p53; Genetic Therapy; Humans; Lung Neoplasms; Mice; Mice, Nude; Point Mutation; Tetracycline; Transcriptional Activation; Tumor Cells, Cultured