Engagement of integrinβ1 induces resistance of bladder cancer cells to mitomycin-C

Urology. 2012 Mar;79(3):638-43. doi: 10.1016/j.urology.2011.12.012.

Abstract

Objective: To identify whether integrinβ1 subunit is responsible for the resistance of bladder cancer cell to the therapeutic drug mitomycin-C (MMC), when grown on fibronectin (FN).

Materials and methods: The expression of integrinβ1 on bladder cancer T24 and 5637 cells was examined by the flow cytometer. The adhesion of cells to plates with the absence or presence of FN was determined. Analysis of apoptosis induced by MMC was assessed using the flow cytometer in combination with an integrinβ1-blocking antibody or siRNA targeting the coding region of integrinβ1. Western blot was used to study the expression change of integrinβ1 and its downstream molecules.

Results: Bladder cancer T24 and 5637 cells express high level of integrinβ1 (87.3% ± 2.3 and 90.1% ± 1.9, respectively). Cellular adhesion to FN was significantly reduced by the blocking of integrinβ1. Blocking or silencing of integrinβ1 significantly abolished the drug resistance of cells grown on FN to MMC (P <.05) and inhibited the activation of survival signals phosphoinositide-3 kinase (PI3-K)/Akt.

Conclusion: Integrinβ1-mediated cellular adhesion to FN confers drug resistance to MMC on bladder cancer cells. Knockdown of integrinβ1 may abolish the drug resistance phenotype and sensitize bladder cancer cells to MMC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibiotics, Antineoplastic / pharmacology*
  • Antibiotics, Antineoplastic / therapeutic use
  • Apoptosis / drug effects
  • Blotting, Western
  • Carcinoma, Transitional Cell / drug therapy
  • Carcinoma, Transitional Cell / physiopathology*
  • Caspase 10 / metabolism
  • Caspase 3 / metabolism
  • Cell Adhesion / drug effects
  • Cell Line, Tumor
  • Colorimetry
  • Culture Media
  • Cytoprotection / physiology
  • Drug Resistance, Neoplasm / physiology*
  • Fibronectins / metabolism
  • Flow Cytometry
  • Gene Knockdown Techniques
  • Gene Silencing
  • Humans
  • Integrin beta1 / genetics
  • Integrin beta1 / metabolism*
  • Mitomycin / pharmacology*
  • Mitomycin / therapeutic use
  • Signal Transduction / physiology
  • Transfection
  • Urinary Bladder Neoplasms / drug therapy
  • Urinary Bladder Neoplasms / physiopathology*

Substances

  • Antibiotics, Antineoplastic
  • Culture Media
  • Fibronectins
  • Integrin beta1
  • Mitomycin
  • Caspase 10
  • Caspase 3