MicroRNA-7 targets IGF1R (insulin-like growth factor 1 receptor) in tongue squamous cell carcinoma cells

Biochem J. 2010 Nov 15;432(1):199-205. doi: 10.1042/BJ20100859.

Abstract

miR-7 (microRNA-7) has been characterized as a tumour suppressor in several human cancers. It targets a number of proto-oncogenes that contribute to cell proliferation and survival. However, the mechanism(s) by which miR-7 suppresses tumorigenesis in TSCC (tongue squamous cell carcinoma) is unknown. The present bioinformatics analysis revealed that IGF1R (insulin-like growth factor 1 receptor) mRNA is a potential target for miR-7. Ectopic transfection of miR-7 led to a significant reduction in IGF1R at both the mRNA and protein levels in TSCC cells. Knockdown of miR-7 in TSCC cells enhanced IGF1R expression. Direct targeting of miR-7 to three candidate binding sequences located in the 3'-untranslated region of IGF1R mRNA was confirmed using luciferase-reporter-gene assays. The miR-7-mediated down-regulation of IGF1R expression attenuated the IGF1 (insulin-like growth factor 1)-induced activation of Akt (protein kinase B) in TSCC cell lines, which in turn resulted in a reduction in cell proliferation and cell-cycle arrest, and an enhanced apoptotic rate. Taken together, the present results demonstrated that miR-7 regulates the IGF1R/Akt signalling pathway by post-transcriptional regulation of IGF1R. Our results indicate that miR-7 plays an important role in TSCC and may serve as a novel therapeutic target for TSCC patients.

Publication types

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

MeSH terms

  • 3' Untranslated Regions / genetics
  • Apoptosis / drug effects
  • Base Sequence
  • Binding Sites / genetics
  • Blotting, Western
  • Carcinoma, Squamous Cell / genetics
  • Carcinoma, Squamous Cell / metabolism
  • Carcinoma, Squamous Cell / pathology
  • Cell Cycle / drug effects
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Down-Regulation*
  • Enzyme Activation / drug effects
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Insulin-Like Growth Factor I / pharmacology
  • Luciferases / genetics
  • Luciferases / metabolism
  • MicroRNAs / genetics*
  • Proto-Oncogene Proteins c-akt / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Receptor, IGF Type 1 / genetics*
  • Receptor, IGF Type 1 / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tongue Neoplasms / genetics
  • Tongue Neoplasms / metabolism
  • Tongue Neoplasms / pathology
  • Transfection

Substances

  • 3' Untranslated Regions
  • MIRN7 microRNA, human
  • MicroRNAs
  • RNA, Messenger
  • Insulin-Like Growth Factor I
  • Luciferases
  • Receptor, IGF Type 1
  • Proto-Oncogene Proteins c-akt