Comparison of the efficacy of 7-hydroxystaurosporine (UCN-01) and other staurosporine analogs to abrogate cisplatin-induced cell cycle arrest in human breast cancer cell lines

Biochem Pharmacol. 1999 Dec 1;58(11):1713-21. doi: 10.1016/s0006-2952(99)00258-0.


DNA-damaging agents such as cisplatin arrest cell cycle progression at either the G1, S, or G2 phase, although the G1 arrest is seen only in cells expressing the wild-type p53 tumor suppressor protein. Caffeine has been shown to abrogate the S and G2 arrest in p53-defective cells and to enhance cytotoxicity, but at concentrations too toxic to administer to humans. We have reported that 7-hydroxystaurosporine (UCN-01) also overcomes S and G2 phase arrest and enhances the cytotoxicity of cisplatin. We show here that UCN-01 at non-cytotoxic concentrations abrogated S and G2 arrest induced by cisplatin in two p53-defective human breast cancer cell lines. UCN-01 pushed the cells through S phase and mitosis, with subsequent apoptosis. Inhibition of mitosis with nocodazole reduced the apoptosis induced by UCN-01 plus cisplatin. Seven staurosporine analogs were compared for their ability to abrogate cell cycle arrest. Staurosporine was as effective as UCN-01 at abrogating S and G2 arrest, but the concentrations required were cytotoxic. K252a abrogated S phase arrest but failed to abrogate G2 arrest because alone it induced G2 arrest. Hence, K252a did not enhance cisplatin-induced cytotoxicity because it failed to push the cells through a lethal mitosis. None of the other analogs influenced cell cycle progression at the concentrations tested. Accordingly, UCN-01 was the only analog that overcame cell cycle arrest and enhanced the cytotoxicity of cisplatin while exhibiting no cytotoxicity of its own. Hence, UCN-01 remains the most promising candidate for testing clinically in combination with cisplatin.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alkaloids / pharmacology*
  • Antineoplastic Agents / pharmacology*
  • Breast Neoplasms
  • Cell Cycle / drug effects*
  • Cisplatin / antagonists & inhibitors
  • Cisplatin / pharmacology
  • Drug Interactions
  • Enzyme Inhibitors / pharmacology
  • Flow Cytometry
  • Humans
  • Staurosporine / analogs & derivatives
  • Staurosporine / pharmacology*
  • Tumor Cells, Cultured


  • Alkaloids
  • Antineoplastic Agents
  • Enzyme Inhibitors
  • 7-hydroxystaurosporine
  • Staurosporine
  • Cisplatin