Biochemical and Biophysical Research Communications, Vol.331, No.2, 648-657, 2005
Increased BNip3 and decreased mutant p53 in cisplatin-sensitive PDT-resistant HT29 cells
We have reported previously the isolation of three photodynamic therapy (PDT)-resistant human colon carcinoma HT29 cell lines that shorn increased expression of the Hsp27 and BNip3 protein and a decreased expression of the mutant p53 protein compared to parental HT29 cells. Since Mutant p53 and increased expression of Hsp27 liar c been associated with resistance to various chemotherapeutic agents. whereas BNip3 is a potent inducer of apoptosis, we were interested in determining whether these PDT-resistant cells were cross-resistant to other cytotoxic agents. We report here that the PDT-resistant HT29 cell lines showed a significant increase in cisplatin sensitivity and an increase in both Spontaneous and cisplatin-induced apoptosis compared to parental HT29 cells. In addition. the cisplatin sensitivity of the PDT-resistant HT29 variants and several other clonal variants of HT29 cells correlated with increased BNip3 and decreased mutant p53 protein levels. but not Hsp27 protein levels, © 2005 Elsevicr Inc. All rights reserved.