Novel role of c-jun N-terminal kinase in regulating the initiation of cap-dependent translation

Int J Oncol. 2012 Feb;40(2):577-82. doi: 10.3892/ijo.2011.1252. Epub 2011 Nov 4.

Abstract

Initiation of protein translation by the 5' mRNA cap is a tightly regulated step in cell growth and proliferation. Aberrant activation of cap-dependent translation is a hallmark of many cancers including non-small cell lung cancer. The canonical signaling mechanisms leading to translation initiation include activation of the Akt/mTOR pathway in response to the presence of nutrients and growth factors. We have previously observed that inhibition of c-jun N-terminal kinase (JNK) leads to inactivation of cap-dependent translation in mesothelioma cells. Since JNK is involved in the genesis of non-small cell lung cancer (NSCLC), we hypothesized that JNK could also be involved in activating cap-dependent translation in NSCLC cells and could represent an alternative pathway regulating translation. In a series of NSCLC cell lines, inhibition of JNK using SP600125 resulted in inhibition of 4E-BP1 phosphorylation and a decrease in formation of the cap-dependent translation complex, eIF4F. Furthermore, we show that JNK-mediated inhibition of translation is independent of mTOR. Our data provide evidence that JNK is involved in the regulation of translation and has potential as a therapeutic target in NSCLC.

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Anthracenes / pharmacology
  • Apoptosis
  • Apoptosis Regulatory Proteins / metabolism
  • Carcinoma, Non-Small-Cell Lung / genetics
  • Carcinoma, Non-Small-Cell Lung / metabolism
  • Cell Cycle Proteins
  • Cell Line, Tumor
  • Cell Proliferation
  • Eukaryotic Initiation Factor-4G / metabolism
  • Humans
  • JNK Mitogen-Activated Protein Kinases / antagonists & inhibitors
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • JNK Mitogen-Activated Protein Kinases / physiology*
  • Nucleocytoplasmic Transport Proteins / metabolism
  • Phosphoproteins / metabolism
  • Phosphorylation
  • Protein Binding
  • Protein Biosynthesis*
  • RNA Caps / genetics*
  • RNA Caps / metabolism
  • Sirolimus / pharmacology
  • TOR Serine-Threonine Kinases / antagonists & inhibitors
  • TOR Serine-Threonine Kinases / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Anthracenes
  • Apoptosis Regulatory Proteins
  • Cell Cycle Proteins
  • EIF4EBP1 protein, human
  • EIF4ENIF1 protein, human
  • EIF4G1 protein, human
  • Eukaryotic Initiation Factor-4G
  • Nucleocytoplasmic Transport Proteins
  • Phosphoproteins
  • RNA Caps
  • pyrazolanthrone
  • MTOR protein, human
  • TOR Serine-Threonine Kinases
  • JNK Mitogen-Activated Protein Kinases
  • Sirolimus