Various forms of mutant p53 confer sensitivity to cisplatin and doxorubicin in bladder cancer cells

Purposes: The nature of p53 mutation has been reported to affect cellular responses to chemotherapy. We characterized the impact of p53 mutations on drug resistance in bladder cancer cells. Materials and Methods: Various human p53 mutants (V143A, V173L, H179Q, N247I and R273H) were introduced to the TCC-SUP bladder carcinoma cell line to establish stable transfectants. The expression of mutant p53 was demonstrated by reverse transcriptase-polymerase chain reaction and immunocytochemical analysis. The sensitivity to cisplatin and doxorubicin in these transfectants was determined by trypan blue exclusion. Cell death mediated by cisplatin and doxorubicin was characterized by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling analysis, Hoechst 33258 staining and annexin-V binding assay. Results: The expression of all forms of mutant p53 protein except p53His273 enhanced sensitivity to cisplatin and doxorubicin. The chemosensitivity of p53His273 transfectants is similar to that of parental TCC-SUP and control transfectants. Cisplatin induced cell death undergoes apoptosis, as demonstrated by Hoechst staining, annexin-V assay and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling, respectively. In contrast, doxorubicin induced cell death probably occurs through a nonapoptotic pathway. Conclusions: These results indicated that the nature of p53 mutations may affect the cellular response to anticancer drugs and many forms of mutant p53 protein may enhance chemosensitivity through apoptotic or nonapoptotic pathways in bladder cancer cells.