In vivo RNAi screening identifies a mechanism of sorafenib resistance in liver cancer

Nat Med. 2014 Oct;20(10):1138-46. doi: 10.1038/nm.3679. Epub 2014 Sep 14.

Abstract

In solid tumors, resistance to therapy inevitably develops upon treatment with cytotoxic drugs or molecularly targeted therapies. Here, we describe a system that enables pooled shRNA screening directly in mouse hepatocellular carcinomas (HCC) in vivo to identify genes likely to be involved in therapy resistance. Using a focused shRNA library targeting genes located within focal genomic amplifications of human HCC, we screened for genes whose inhibition increased the therapeutic efficacy of the multikinase inhibitor sorafenib. Both shRNA-mediated and pharmacological silencing of Mapk14 (p38α) were found to sensitize mouse HCC to sorafenib therapy and prolong survival by abrogating Mapk14-dependent activation of Mek-Erk and Atf2 signaling. Elevated Mapk14-Atf2 signaling predicted poor response to sorafenib therapy in human HCC, and sorafenib resistance of p-Mapk14-expressing HCC cells could be reverted by silencing Mapk14. Our results suggest that a combination of sorafenib and Mapk14 blockade is a promising approach to overcoming therapy resistance of human HCC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activating Transcription Factor 2 / metabolism
  • Animals
  • Antineoplastic Agents / pharmacology*
  • Carcinoma, Hepatocellular / drug therapy
  • Carcinoma, Hepatocellular / genetics
  • Carcinoma, Hepatocellular / metabolism
  • Drug Resistance, Neoplasm / genetics
  • Female
  • Humans
  • Liver Neoplasms / drug therapy
  • Liver Neoplasms / genetics
  • Liver Neoplasms / metabolism
  • Liver Neoplasms, Experimental / drug therapy*
  • Liver Neoplasms, Experimental / genetics*
  • Liver Neoplasms, Experimental / metabolism
  • MAP Kinase Signaling System / drug effects
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mitogen-Activated Protein Kinase 14 / antagonists & inhibitors*
  • Mitogen-Activated Protein Kinase 14 / genetics*
  • Mitogen-Activated Protein Kinase 14 / metabolism
  • Niacinamide / analogs & derivatives*
  • Niacinamide / pharmacology
  • Phenylurea Compounds / pharmacology*
  • Protein Kinase Inhibitors / pharmacology
  • RNA Interference
  • RNA, Small Interfering / genetics
  • Signal Transduction
  • Sorafenib
  • Xenograft Model Antitumor Assays

Substances

  • Activating Transcription Factor 2
  • Antineoplastic Agents
  • Atf2 protein, mouse
  • Phenylurea Compounds
  • Protein Kinase Inhibitors
  • RNA, Small Interfering
  • Niacinamide
  • Sorafenib
  • Mitogen-Activated Protein Kinase 14