Oncolytic effects of a novel influenza A virus expressing interleukin-15 from the NS reading frame

PLoS One. 2012;7(5):e36506. doi: 10.1371/journal.pone.0036506. Epub 2012 May 1.

Abstract

Oncolytic influenza A viruses with deleted NS1 gene (delNS1) replicate selectively in tumour cells with defective interferon response and/or activated Ras/Raf/MEK/ERK signalling pathway. To develop a delNS1 virus with specific immunostimulatory properties, we used an optimised technology to insert the interleukin-15 (IL-15) coding sequence into the viral NS gene segment (delNS1-IL-15). DelNS1 and delNS1-IL-15 exerted similar oncolytic effects. Both viruses replicated and caused caspase-dependent apoptosis in interferon-defective melanoma cells. Virus replication was required for their oncolytic activity. Cisplatin enhanced the oncolytic activity of delNS1 viruses. The cytotoxic drug increased delNS1 replication and delNS1-induced caspase-dependent apoptosis. Interference with MEK/ERK signalling by RNAi-mediated depletion or the MEK inhibitor U0126 did not affect the oncolytic effects of the delNS1 viruses. In oncolysis sensitive melanoma cells, delNS1-IL-15 (but not delNS1) infection resulted in the production of IL-15 levels ranging from 70 to 1140 pg/mL in the cell culture supernatants. The supernatants of delNS1-IL-15-infected (but not of delNS1-infected) melanoma cells induced primary human natural killer cell-mediated lysis of non-infected tumour cells. In conclusion, we constructed a novel oncolytic influenza virus that combines the oncolytic activity of delNS1 viruses with immunostimulatory properties through production of functional IL-15. Moreover, we showed that the oncolytic activity of delNS1 viruses can be enhanced in combination with cytotoxic anti-cancer drugs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Chloromethyl Ketones / pharmacology
  • Animals
  • Antineoplastic Agents / pharmacology
  • Apoptosis / drug effects
  • Blotting, Western
  • Caspase Inhibitors
  • Caspases / metabolism
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Cells, Cultured
  • Chlorocebus aethiops
  • Cisplatin / pharmacology
  • Cysteine Proteinase Inhibitors / pharmacology
  • Gene Deletion
  • Humans
  • Influenza A Virus, H1N1 Subtype / genetics*
  • Influenza A Virus, H1N1 Subtype / growth & development
  • Interleukin-15 / genetics*
  • Interleukin-15 / metabolism
  • Melanoma / genetics
  • Melanoma / pathology
  • Melanoma / virology
  • Mitogen-Activated Protein Kinase 1 / genetics
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3 / genetics
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • Oncolytic Viruses / genetics*
  • Oncolytic Viruses / growth & development
  • RNA Interference
  • Vero Cells
  • Viral Nonstructural Proteins / genetics*
  • Virus Replication / drug effects

Substances

  • Amino Acid Chloromethyl Ketones
  • Antineoplastic Agents
  • Caspase Inhibitors
  • Cysteine Proteinase Inhibitors
  • Interleukin-15
  • Viral Nonstructural Proteins
  • benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone
  • MAPK1 protein, human
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Caspases
  • Cisplatin