Enhancement of cisplatin-induced cytotoxicity by ROCK inhibitor through suppression of focal adhesion kinase-independent mechanism in lung carcinoma cells

Int J Oncol. 2003 Oct;23(4):1079-85.

Abstract

Intracellular signaling through Rho-associated coiled-coil forming kinase (ROCK) is a target of antimetastatic therapy and is proposed to be involved in carcinogenesis. Focal adhesion kinase (FAK) functions downstream of ROCK and participates in anti-apoptotic signaling. We hypothesized that a specific ROCK inhibitor, Y-27632, may exert a pro-apoptotic effect in combination with anticancer agents through the suppression of FAK. A549 lung carcinoma cells were treated with Y-27632 and cisplatin. The simultaneous combination did not exert any additional effect, whereas sequential treatment, in which cisplatin followed Y-27632, enhanced cytotoxicity in concentration- and time-dependent manner. Y-27632 did not suppress tyrosine phosphorylation of FAK in A549-FAK, the active form of FAK expressing A549 cells, as observed in parental cells. Nevertheless, the pretreatment of A549-FAK cells with Y-27632 still enhanced cisplatin-induced cytotoxicity. It was concluded that the ROCK inhibitor enhances cisplatin-induced cytotoxicity through FAK suppression-independent mechanism(s). These observations raise the possibility that the inhibition of the ROCK-mediated signal enhances the effect of anti-cancer agents in addition to its antimetastatic property.

MeSH terms

  • Amides / pharmacology
  • Blotting, Western
  • Carcinoma / drug therapy*
  • Cell Line, Tumor
  • Cisplatin / pharmacology*
  • Dose-Response Relationship, Drug
  • Enzyme Inhibitors / pharmacology
  • Flow Cytometry
  • Focal Adhesion Kinase 1
  • Focal Adhesion Protein-Tyrosine Kinases
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Lung Neoplasms / drug therapy*
  • Neoplasm Metastasis
  • Phosphorylation
  • Plasmids / metabolism
  • Precipitin Tests
  • Protein Serine-Threonine Kinases / antagonists & inhibitors*
  • Protein Serine-Threonine Kinases / pharmacology*
  • Protein-Tyrosine Kinases / antagonists & inhibitors*
  • Pyridines / pharmacology
  • Signal Transduction
  • Time Factors
  • Transfection
  • Tyrosine / metabolism
  • rho-Associated Kinases

Substances

  • Amides
  • Enzyme Inhibitors
  • Intracellular Signaling Peptides and Proteins
  • Pyridines
  • Y 27632
  • Tyrosine
  • Protein-Tyrosine Kinases
  • Focal Adhesion Kinase 1
  • Focal Adhesion Protein-Tyrosine Kinases
  • PTK2 protein, human
  • Protein Serine-Threonine Kinases
  • rho-Associated Kinases
  • Cisplatin