title: Increased BNip3 and decreased mutant p53 in cisplatin-sensitive PDT-resistant HT29 cells.
abstract: We have reported previously the isolation of three photodynamic therapy (PDT)-resistant human colon carcinoma HT29 cell lines that show 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 have 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.
authors.affiliation: Department of Biology, McMaster University, Hamilton, Ont., Canada.
authors.forename: Natalie
authors.initials: N
authors.lastname: Zacal
authors.forename: Myrna
authors.initials: M
authors.lastname: Espiritu
authors.forename: Gurmit
authors.initials: G
authors.lastname: Singh
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Rainbow
mesh_terms: D000199:Actins / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D016158:Genes, p53 / Q000235:genetics; D055551:HSP27 Heat-Shock Proteins; D019073:HT29 Cells; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D018832:Molecular Chaperones; D009154:Mutation / Q000235:genetics*; D009363:Neoplasm Proteins / Q000378:metabolism; D010778:Photochemotherapy; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000378:metabolism*
chemical_list: D000199:Actins; C090121:BNIP3 protein, human; D055551:HSP27 Heat-Shock Proteins; C057725:HSPB1 protein, human; D006360:Heat-Shock Proteins; D008565:Membrane Proteins; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; D002945:Cisplatin