Cytochrome c release is upstream to activation of caspase-9, caspase-8, and caspase-3 in the enhanced apoptosis of anaplastic thyroid cancer cells induced by manumycin and paclitaxel

J Clin Endocrinol Metab. 2001 Oct;86(10):4731-40. doi: 10.1210/jcem.86.10.7860.

Abstract

We previously demonstrated that the combination of a farnesyltransferase inhibitor, manumycin A, and paclitaxel had a synergistic antineoplastic effect on anaplastic thyroid cancer. In this study we investigated the apoptosis pathway involved. In ARO and KAT-4 cells, manumycin- plus paclitaxel-induced DNA fragmentation was blocked by the inhibitors of caspase-9, caspase-8, and caspase-3. The drug combination enhanced the activation of caspase-9, caspase-8, and caspase-3 and cytochrome c release into the cytosol. Cytochrome c release was not affected by the inhibitors of caspase-9, caspase-8 and caspase-3. In a cell-free reconstitution assay, DNA fragmentation occurred after incubating nuclei purified from untreated KAT-4 cells with deoxy-ATP, exogenous cytochrome c and S-100 extracts from control KAT-4 cells, and also after incubation of purified KAT-4 nuclei with S-100 extracts from KAT-4 cells treated with manumycin-plus-paclitaxel. In both cases, the DNA fragmentation was blocked by the inhibitors of caspase-9, caspase-8 and caspase-3. We concluded that the cytochrome c release was upstream of the activation of caspase-9, caspase-8, and caspase-3 in the enhanced apoptosis of anaplastic thyroid cancer cells treated with manumycin plus paclitaxel, and that the interaction between manumycin and paclitaxel occurred at or upstream of cytochrome c in the apoptosis regulatory pathway in anaplastic thyroid cancer cells.

Publication types

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

MeSH terms

  • Antineoplastic Agents, Phytogenic / administration & dosage*
  • Apoptosis / drug effects*
  • Caspase 3
  • Caspase 8
  • Caspase 9
  • Caspases / metabolism*
  • Cytochrome c Group / metabolism*
  • Cytosol / enzymology
  • DNA Fragmentation / drug effects
  • Enzyme Activation / drug effects
  • Enzyme Inhibitors / administration & dosage*
  • Humans
  • Paclitaxel / administration & dosage*
  • Polyenes / administration & dosage*
  • Polyunsaturated Alkamides
  • Thyroid Neoplasms / drug therapy*
  • Thyroid Neoplasms / enzymology
  • Thyroid Neoplasms / pathology
  • Tumor Cells, Cultured

Substances

  • Antineoplastic Agents, Phytogenic
  • Cytochrome c Group
  • Enzyme Inhibitors
  • Polyenes
  • Polyunsaturated Alkamides
  • CASP3 protein, human
  • CASP8 protein, human
  • CASP9 protein, human
  • Caspase 3
  • Caspase 8
  • Caspase 9
  • Caspases
  • manumycin
  • Paclitaxel