Synergistic cytotoxicity of cisplatin and topotecan or SN-38 in a panel of eight solid-tumor cell lines in vitro

Cancer Chemother Pharmacol. 1998;41(4):307-16. doi: 10.1007/s002800050744.


The cytotoxicity of cisplatin alone and in combination with topotecan (TPT) or SN-38, two novel topoisomerase I (topo I) inhibitors, was determined in a panel of eight well-characterized human solid-tumor cell lines. Interactions between cisplatin and these topo I inhibitors were investigated using three different administration schedules: (1) simultaneous incubation (C + T and C + S), (2) cisplatin followed by TPT or SN-38 (C --> T and C --> S), and (3) TPT or SN-38 followed by cisplatin (T --> C and S --> C). Median-effect analysis revealed synergistic cytotoxicity in seven of the eight cell lines used. In addition, a significant schedule-dependent synergistic cytotoxicity was found in three of the cell lines used, with C --> T (or C --> S) being the most active schedule. The formation and repair of total cisplatin-DNA adducts in the IGROV-1 ovarian cancer cell line and its cisplatin-resistant subline IGROV(CDDP) was not significantly affected by TPT on simultaneous incubation. In contrast, the number of cisplatin-DNA interstrand cross-links detected in the IGROV-1 and IGROV(CDDP) lines at certain time points was significantly lower after coincubation of the cells with TPT. Assessment of the cell-cycle distribution revealed an accumulation of cells in the G2/M phase after exposure to cisplatin. After exposure to TPT a different pattern was observed that was cell-type-specific and dependent upon the TPT concentration. Although up to 4-fold differences in topo I activity were observed in this panel of cell lines, these differences did not appear to be related to the synergy observed between cisplatin and TPT or SN-38. The observed synergy may at least partly be explained by the increased retention of cisplatin-DNA interstrand cross-links in the presence of topo I inhibitors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Combined Chemotherapy Protocols / adverse effects*
  • Antineoplastic Combined Chemotherapy Protocols / pharmacology
  • Camptothecin / adverse effects
  • Camptothecin / analogs & derivatives*
  • Camptothecin / pharmacology
  • Cisplatin / adverse effects*
  • Cisplatin / pharmacology
  • DNA Adducts / pharmacology*
  • Drug Administration Schedule
  • Drug Synergism
  • Humans
  • In Vitro Techniques
  • Irinotecan
  • Topotecan / adverse effects*
  • Topotecan / pharmacology
  • Tumor Cells, Cultured / drug effects


  • DNA Adducts
  • Irinotecan
  • Topotecan
  • Cisplatin
  • Camptothecin