WILD TYPE p53 STIMULATES VINCRISTINE-INDUCED APOPTOSIS

Recent studies indicate that wild-type p53 can trigger cell apoptosis induced by many chemotherapeutic agents which induce DNA damage or cause disruptions of DNA metabolism, such as ADM, 5-FU, VP-16 and radiation. We introduced the wild-type p53 gene into a MDR cell line KB_V200 in which the endogenous p53 was found to be rearranged. By G418 selection and Northern blot analysis, a G418-resistant clone named KB_V200-p53 was obtained which continuously expressed the exogenous wild-type p53 mRNA After treatment with Vincritine(VCR), the wild type p53-expression cells presented typical morphology characteristic of apoptosis analysed under electron and fluorescence microscopes. Flow cytometer analysis showed that the KB_V200-p53 cells were more readily undergo apoptosis than their parental cells KB_V200 After treatment with VCR 600 nmol·L^-1 for 24 h, the apoptotic percentage of KB_V200-p53 and KB_V200 cells was about 42.4% and 8.4%, respectively. This result indicates that wild-type p53 stimulates VCRinduced apoptosis in KB_V200 cells.