Effect of mouse p53 minigene on lung cancer cells with different 172 structures regulated by tetracycline

Objective To investigate the effect of mouse 172 wild type p53(Arg), pseudo wild mutant type p53(Arg→Leu) and mutant type p53(Arg→His) induced by absence of tetracycline on the growth of PG cell line. Methods Three variant types of p53 minigene were sub cloned by gene recombination into an expression vector which was controlled by tetracycline. Through LipofectAMINE, the vectors were transfected into p53 defective PG(248CGG→CTT) cells, and the transfectants were screened in the selecting medium containing puromycin. Tumor suppressing effects were studied by MTT absorption, flow cytometry and Western blotting. Results Wild type p53 and pseudo wild mutant type p53 could lead cells to decrease their growth rates, arrest cell cycle and transactivation of p21 WAF1 . Mutant type p53 was defective in tumor suppression. Conclusion Wild type p53 and pseudo wild type p53 may inhibit cell growth and induce cell cycle arrest. Some p53 variants such as 172 Arg→Leu can still retain the tumor suppression function of the wild type.