MicroRNA-sensitive oncolytic measles viruses for cancer-specific vector tropism

Mol Ther. 2011 Jun;19(6):1097-106. doi: 10.1038/mt.2011.55. Epub 2011 Apr 5.

Abstract

Oncolytic measles viruses (MV) derived from the live attenuated vaccine strain have been engineered for increased tumor-cell specificity, and are currently under investigation in clinical trials including a phase I study for glioblastoma multiforme (GBM). Recent preclinical studies have shown that the cellular tropism of several viruses can be controlled by inserting microRNA-target sequences into their genomes, thereby inhibiting spread in tissues expressing cognate microRNAs. Since neuron-specific microRNA-7 is downregulated in gliomas but highly expressed in normal brain tissue, we engineered a microRNA-sensitive virus containing target sites for microRNA-7 in the 3'-untranslated region of the viral fusion gene. In presence of microRNA-7 this modification inhibits translation of envelope proteins, restricts viral spread, and progeny production. Even though highly attenuated in presence of microRNA-7, this virus retained full efficacy against glioblastoma xenografts. Furthermore, microRNA-mediated inhibition protected genetically modified mice susceptible to MV infection from a potentially lethal intracerebral challenge. Importantly, endogenous microRNA-7 expression in primary human brain resections tightly restricted replication and spread of microRNA-sensitive virus. This is proof-of-concept that tropism restriction by tissue-specific microRNAs can be adapted to oncolytic MV to regulate viral replication and gene expression to maximize tumor specificity without compromising oncolytic efficacy.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain Neoplasms / therapy
  • Cell Line
  • Cell Line, Tumor
  • Cell Survival / genetics
  • Cell Survival / physiology*
  • Chlorocebus aethiops
  • Female
  • Genetic Vectors / genetics
  • Glioblastoma / therapy
  • Glioma / therapy
  • Humans
  • Immunoblotting
  • In Vitro Techniques
  • Measles virus / genetics*
  • Measles virus / physiology
  • Mice
  • Mice, Inbred NOD
  • Mice, SCID
  • MicroRNAs / genetics*
  • Oncolytic Virotherapy
  • Oncolytic Viruses / genetics
  • Oncolytic Viruses / physiology*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Vero Cells
  • Xenograft Model Antitumor Assays

Substances

  • MicroRNAs