An improved isoprenylcysteine carboxylmethyltransferase inhibitor induces cancer cell death and attenuates tumor growth in vivo.

Journal Article (Journal Article)

Inhibitors of isoprenylcysteine carboxylmethyltransferase (Icmt) are promising anti-cancer agents, as modification by Icmt is an essential component of the protein prenylation pathway for a group of proteins that includes Ras GTPases. Cysmethynil, a prototypical indole-based inhibitor of Icmt, effectively inhibits tumor cell growth. However, the physical properties of cysmethynil, such as its low aqueous solubility, make it a poor candidate for clinical development. A novel amino-derivative of cysmethynil with superior physical properties and marked improvement in efficacy, termed compound 8.12, has recently been reported. We report here that Icmt (-/-) mouse embryonic fibroblasts (MEFs) are much more resistant to compound 8.12-induced cell death than their wild-type counterparts, providing evidence that the anti-proliferative effects of this compound are mediated through an Icmt specific mechanism. Treatment of PC3 prostate and HepG2 liver cancer cells with compound 8.12 resulted in pre-lamin A accumulation and Ras delocalization from the plasma membrane, both expected outcomes from inhibition of the Icmt-catalyzed carboxylmethylation. Treatment with compound 8.12 induced cell cycle arrest, autophagy and cell death, and abolished anchorage-independent colony formation. Consistent with its greater in vitro efficacy, compound 8.12 inhibited tumor growth with greater potency than cysmethynil in a xenograft mouse model. Further, a drug combination study identified synergistic antitumor efficacy of compound 8.12 and the epithelial growth factor receptor (EGFR)-inhibitor gefitinib, possibly through enhancement of autophagy. This study establishes compound 8.12 as a pharmacological inhibitor of Icmt that is an attractive candidate for further preclinical and clinical development.

Full Text

Duke Authors

Cited Authors

  • Lau, HY; Ramanujulu, PM; Guo, D; Yang, T; Wirawan, M; Casey, PJ; Go, M-L; Wang, M

Published Date

  • September 2014

Published In

Volume / Issue

  • 15 / 9

Start / End Page

  • 1280 - 1291

PubMed ID

  • 24971579

Pubmed Central ID

  • PMC4128870

Electronic International Standard Serial Number (EISSN)

  • 1555-8576

Digital Object Identifier (DOI)

  • 10.4161/cbt.29692


  • eng

Conference Location

  • United States