Ouabain Mediates Integrin Switch in Human Lung Cancer Cells

Background: Physiological effects of ouabain, an endogenous human hormone, are being intensively investigated. However, its role in regulation of integrin pattern in lung cancer is largely unknown. The switching in the expression pattern of integrins is recognized as an important factor facilitating metastasis of several cancers. Materials and Methods: Cytotoxicity and proliferative effects of ouabain on H460 lung cancer cells were evaluated by the MTT assay. The levels of integrin proteins in response to ouabain were determined by western blotting. Anchorage-independent growth and migration behaviors were performed by the wound healing assay and colony formation assay, respectively. Results: Herein, the results suggested that exposure of the lung cancer cells to physiological concentrations of ouabain significantly altered the level of integrins. Ouabain suppressed integrin alpha(4), alpha(5), alpha(v), beta(3) and beta(4), whereas it had no significant effect on integrin beta(1) and beta(4). According to the switch patterns of integrins, ouabain treatment resulted in a dramatic reduction of cell colony size and inhibition of cancer cell migration. However, ouabain-induced integrin switch had only a slight effect on chemotherapeutic drug susceptibility. Conclusion: Ouabain may have a role in suppressing cancer metastasis via integrin regulation.