miR-145 inhibits invasion of bladder cancer cells by targeting PAK1

Urol Oncol. 2014 Aug;32(6):846-54. doi: 10.1016/j.urolonc.2014.01.003. Epub 2014 Jun 20.


Objectives: MicroRNAs play important roles in cancer. In many cancers, miR-145 acts as a tumor suppressor, and it is down-regulated in bladder cancer. In the present study, we explored the modulation of oncogenic gene PAK1 by miR-145 in bladder cancer.

Material and methods: Expression of miR-145 was detected in bladder cancer tissues and cell lines by quantitative real-time polymerase chain reaction. Through the bioinformatics approach, PAK1 has been predicted to be a direct target of miR-145 and was confirmed by the PAK1 messenger RNA 3'-untranslated region luciferase activity assay. To investigate whether miR-145 regulates PAK1 expression, it was overexpressed in J82 and T24 bladder cancer cells. In 10 paired bladder normal and tumor tissues, we determined the relationship between miR-145 and PAK1 through quantitative real-time polymerase chain reaction and western blot. By using transwell invasion assay and western blotting analysis, we investigated the effects of miR-145 and PAK1 on bladder cancer cell invasion and expression of invasion marker genes.

Results: The level of miR-145 decreases and PAK1 protein expression up-regulates in bladder cancer tissue, as compared with the paired normal bladder tissue. Moreover, miR-145 directly targets PAK1 in bladder cancer cells. The level of miR-145 negatively correlates with PAK1 protein expression in bladder cancer. In addition, PAK1 promotes invasion and enhances the expression and activity of MMP-9, whereas miR-145 inhibits bladder cancer cell invasion and expressions of PAK1 and MMP-9.

Conclusions: Our results indicate that miR-145 inhibits bladder cancer cell invasion, at least partly through targeting PAK1. Restoration or replacement of miR-145 could be an efficient approach to inhibit PAK1 and bladder cancer development in the tumor therapy.

Keywords: Bladder cancer; Invasion; MMP-9; PAK1; miR-145.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 5' Untranslated Regions / genetics
  • Adult
  • Aged
  • Base Sequence
  • Blotting, Western
  • Cell Line, Tumor
  • Female
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Male
  • Matrix Metalloproteinase 9 / genetics
  • Matrix Metalloproteinase 9 / metabolism
  • MicroRNAs / genetics*
  • Microscopy, Confocal
  • Middle Aged
  • Neoplasm Invasiveness
  • RNA Interference
  • Reverse Transcriptase Polymerase Chain Reaction
  • Urinary Bladder Neoplasms / genetics*
  • Urinary Bladder Neoplasms / metabolism
  • Urinary Bladder Neoplasms / pathology
  • p21-Activated Kinases / genetics*
  • p21-Activated Kinases / metabolism


  • 5' Untranslated Regions
  • MIRN145 microRNA, human
  • MicroRNAs
  • PAK1 protein, human
  • p21-Activated Kinases
  • Matrix Metalloproteinase 9