Adenovirus expressing dual c-Met-specific shRNA exhibits potent antitumor effect through autophagic cell death accompanied by senescence-like phenotypes in glioblastoma cells

Oncotarget. 2015 Feb 28;6(6):4051-65. doi: 10.18632/oncotarget.3018.

Abstract

c-Met, a cognate receptor tyrosine kinase of hepatocyte growth factor, is overexpressed and/or mutated in number of tumors. Therefore, abrogation of c-Met signaling may serve as potential therapeutic targets. In this study, we generated Ads expressing single shRNA specific to c-Met (shMet) (dl/shMet4 and dl/shMet5) or dual shRNAs specific to c-Met (dl/shMet4+5); and examined the therapeutic potential of these newly engineered Ads in targeting c-Met, and delineated their mechanism of action in vitro and in vivo. Ads expressing shMet induced knock-down in c-Met, and phenotypically resulted in autophagy-like features including appearance of membranousvacuoles, formation of acidic vesicular organelles, and cleavage and recruitment of microtubule-associated protein1 light chain 3 to autophagosomes. Ads expressing shMet also suppressed Akt phosphorylation and increased number of senescence-related gene products including SM22, TGase II, and PAI-1. These changes resulted in inhibition of cell proliferation and G2/M arrest of U343 cells. In vivo, intratumoral injection with dl/shMet4+5 resulted in a significant reduction of tumor growth with corresponding increasing overall survival. Histopathological analysis of these treated tumors revealed that Atg5 was highly up-regulated, indicating the therapeutic induction of autophagy. In sum, these results reveal that autophagic cell death induced by shMet-expressing Ads provide a novel strategy for targeting c-Met-expressing tumors through non-apoptotic mechanism of cell death.

Publication types

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

MeSH terms

  • Adenoviridae / genetics
  • Animals
  • Autophagy / genetics
  • Brain Neoplasms / genetics
  • Brain Neoplasms / pathology
  • Brain Neoplasms / therapy*
  • Cell Line, Tumor
  • Gene Knockdown Techniques / methods
  • Genetic Therapy / methods*
  • Glioblastoma / genetics
  • Glioblastoma / pathology
  • Glioblastoma / therapy*
  • Humans
  • Male
  • Mice
  • Mice, Nude
  • Phenotype
  • Proto-Oncogene Proteins c-met / deficiency
  • Proto-Oncogene Proteins c-met / genetics*
  • Proto-Oncogene Proteins c-met / metabolism
  • RNA, Small Interfering / administration & dosage*
  • RNA, Small Interfering / biosynthesis
  • RNA, Small Interfering / genetics
  • Signal Transduction
  • Xenograft Model Antitumor Assays

Substances

  • RNA, Small Interfering
  • MET protein, human
  • Proto-Oncogene Proteins c-met