title: Effect of p53 status on sensitivity to platinum complexes in a human ovarian cancer cell line.
abstract: Wild-type p53 is frequently mutated in late-stage ovarian cancer and has been proposed as a determinant of cisplatin chemosensitivity. We have therefore established a human ovarian cancer cell line differing only in p53 status and characterized its response after treatment with different platinum complexes. The wild-type p53-expressing cell line A2780 was stably transfected with HPV-16 E6 (E6) or an empty vector (VC) as control. Parental A2780 and VC had similar cisplatin sensitivities, whereas E6 was 3- to 4-fold more sensitive as measured by sulforhodamine B and clonogenic assay. E6 was 2- to 3-fold more sensitive to transplatin and the novel cisplatin analog ZD0473 than VC, whereas the trans-platinum analog JM335 was approximately equitoxic. Platinum uptake was similar for all of the cell lines after cisplatin. The removal of platinum-DNA adducts, as measured by atomic absorption spectroscopy, was reduced in E6 compared with VC after cisplatin but similar after JM335. After 10 microM cisplatin, the G(1) population (0-96 h) was reduced in E6 cells compared with VC, whereas the S phase (8-48 h) and G(2) phase (48-96 h) were increased. Similar proportions of VC and E6 cells died by apoptosis, as detected by annexin V binding, but more E6 cells died by necrosis relative to VC. Our results suggest that the loss of functional p53 can increase cisplatin cytotoxicity in A2780, with loss of G(1)/S checkpoint control and decreased cisplatin-DNA adduct repair, but these effects can be circumvented by the use of JM335, which forms different DNA-platinum adducts.
authors.affiliation: Cancer Research Campaign Centre for Cancer Therapeutics, Institute of Cancer Research, Sutton, Surrey, United Kingdom.
authors.forename: K E
authors.initials: KE
authors.lastname: Pestell
authors.forename: S M
authors.initials: SM
authors.lastname: Hobbs
authors.forename: J C
authors.initials: JC
authors.lastname: Titley
authors.forename: L R
authors.initials: LR
authors.lastname: Kelland
authors.forename: M I
authors.initials: MI
authors.lastname: Walton
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology; D018736:DNA Adducts; D004260:DNA Repair / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D005260:Female; D006801:Humans; D009944:Organoplatinum Compounds / Q000494:pharmacology; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D017671:Platinum Compounds / Q000494:pharmacology*; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D018736:DNA Adducts; C089656:JM 335; D009944:Organoplatinum Compounds; D017671:Platinum Compounds; D016159:Tumor Suppressor Protein p53; D002945:Cisplatin