Activation of Cyclic Adenosine Monophosphate Pathway Increases the Sensitivity of Cancer Cells to the Oncolytic Virus M1

Mol Ther. 2016 Feb;24(1):156-65. doi: 10.1038/mt.2015.172. Epub 2015 Sep 16.


Oncolytic virotherapy is a novel and emerging treatment modality that uses replication-competent viruses to destroy cancer cells. Although diverse cancer cell types are sensitive to oncolytic viruses, one of the major challenges of oncolytic virotherapy is that the sensitivity to oncolysis ranges among different cancer cell types. Furthermore, the underlying mechanism of action is not fully understood. Here, we report that activation of cyclic adenosine monophosphate (cAMP) signaling significantly sensitizes refractory cancer cells to alphavirus M1 in vitro, in vivo, and ex vivo. We find that activation of the cAMP signaling pathway inhibits M1-induced expression of antiviral factors in refractory cancer cells, leading to prolonged and severe endoplasmic reticulum (ER) stress, and cell apoptosis. We also demonstrate that M1-mediated oncolysis, which is enhanced by cAMP signaling, involves the factor, exchange protein directly activated by cAMP 1 (Epac1), but not the classical cAMP-dependent protein kinase A (PKA). Taken together, cAMP/Epac1 signaling pathway activation inhibits antiviral factors and improves responsiveness of refractory cancer cells to M1-mediated virotherapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alphavirus / genetics*
  • Animals
  • Apoptosis
  • Cell Line, Tumor
  • Colforsin / administration & dosage*
  • Colforsin / pharmacology
  • Cyclic AMP / metabolism*
  • Endoplasmic Reticulum Stress / drug effects
  • Guanine Nucleotide Exchange Factors / genetics
  • HCT116 Cells
  • Humans
  • Mice
  • Neoplasms / genetics
  • Neoplasms / therapy*
  • Oncolytic Virotherapy
  • Oncolytic Viruses / genetics
  • Signal Transduction / drug effects*


  • Epac protein, mouse
  • Guanine Nucleotide Exchange Factors
  • Colforsin
  • Cyclic AMP