In vitro mechanism study of microtubule assembly inhibition by cis-dichlorodiammine-platinum(II)

Biochem Pharmacol. 1986 Feb 1;35(3):371-5. doi: 10.1016/0006-2952(86)90207-8.

Abstract

The inhibitions of microtubule protein (MTP) and tubulin 6S polymerizations by cis-dichlorodiammine-platinum(II) (CDDP) have been investigated by turbidity measurements and electron microscopy. For 2.5 X 10(-4) M CDDP after 40 min contact time at 27 degrees, the inhibition was 60% for MTP (1.2 mg/ml) and nearly 90% for tubulin 6S (1.2 mg/ml). Microtubules were not present after a 1 hr contact time at 27 degrees with 2.5 X 10(-4) M CDDP. Free sulfhydryl group determinations with 5,5'-dithio-bis-(2-nitrobenzoate) (DTNB) showed that 20.10 (+/- 0.05) sulfhydryl groups were found per tubulin dimer. In the presence of excess CDDP, this number was reduced to 17.74 (+/- 0.05) after a 1 hr contact time at 27 degrees. By using CDDP-tubulin dialysis assays, the CDDP-tubulin complex formation was found to be an irreversible reaction through a covalent binding at the sulfhydryl group sites. By the DEAE filter paper method, CDDP was shown to slightly decrease vinca-alkaloid and colchicine bindings to tubulin likely by inducing a conformational change of the protein.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cisplatin / pharmacology*
  • Colchicine / metabolism
  • Cysteine / metabolism
  • In Vitro Techniques
  • Macromolecular Substances
  • Microscopy, Electron
  • Microtubule Proteins / metabolism*
  • Microtubules / drug effects*
  • Protein Binding / drug effects
  • Swine
  • Tubulin / metabolism
  • Vinca Alkaloids / metabolism

Substances

  • Macromolecular Substances
  • Microtubule Proteins
  • Tubulin
  • Vinca Alkaloids
  • Cysteine
  • Cisplatin
  • Colchicine