Effect of p53 status on sensitivity to platinum complexes in a human ovarian cancer cell line

Mol Pharmacol. 2000 Mar;57(3):503-11. doi: 10.1124/mol.57.3.503.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Cell Cycle / drug effects
  • Cisplatin / pharmacology
  • DNA Adducts
  • DNA Repair / drug effects
  • Drug Screening Assays, Antitumor
  • Female
  • Humans
  • Organoplatinum Compounds / pharmacology
  • Ovarian Neoplasms / drug therapy*
  • Ovarian Neoplasms / metabolism
  • Platinum Compounds / pharmacology*
  • Transfection
  • Tumor Cells, Cultured
  • Tumor Suppressor Protein p53 / drug effects
  • Tumor Suppressor Protein p53 / metabolism*

Substances

  • Antineoplastic Agents
  • DNA Adducts
  • JM 335
  • Organoplatinum Compounds
  • Platinum Compounds
  • Tumor Suppressor Protein p53
  • Cisplatin