Anti-tumor Activity of the Type I PRMT Inhibitor, GSK3368715, Synergizes with PRMT5 Inhibition through MTAP Loss

Cancer Cell. 2019 Jul 8;36(1):100-114.e25. doi: 10.1016/j.ccell.2019.05.014. Epub 2019 Jun 27.

Abstract

Type I protein arginine methyltransferases (PRMTs) catalyze asymmetric dimethylation of arginines on proteins. Type I PRMTs and their substrates have been implicated in human cancers, suggesting inhibition of type I PRMTs may offer a therapeutic approach for oncology. The current report describes GSK3368715 (EPZ019997), a potent, reversible type I PRMT inhibitor with anti-tumor effects in human cancer models. Inhibition of PRMT5, the predominant type II PRMT, produces synergistic cancer cell growth inhibition when combined with GSK3368715. Interestingly, deletion of the methylthioadenosine phosphorylase gene (MTAP) results in accumulation of the metabolite 2-methylthioadenosine, an endogenous inhibitor of PRMT5, and correlates with sensitivity to GSK3368715 in cell lines. These data provide rationale to explore MTAP status as a biomarker strategy for patient selection.

Keywords: MTAP; PRMT5; Type I PRMT; arginine methylation; biomarker; cancer biology; post translational modifications; splicing.

MeSH terms

  • Alternative Splicing
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology*
  • Biomarkers
  • Cell Line, Tumor
  • Drug Synergism
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • Humans
  • Methylation
  • Models, Molecular
  • Molecular Conformation
  • Molecular Structure
  • Protein Binding
  • Protein-Arginine N-Methyltransferases / antagonists & inhibitors*
  • Protein-Arginine N-Methyltransferases / chemistry
  • Purine-Nucleoside Phosphorylase / deficiency*
  • Substrate Specificity

Substances

  • Antineoplastic Agents
  • Biomarkers
  • Enzyme Inhibitors
  • PRMT5 protein, human
  • Protein-Arginine N-Methyltransferases
  • Purine-Nucleoside Phosphorylase
  • 5'-methylthioadenosine phosphorylase