Epithelial-mesenchymal transition mediates anoikis resistance and enhances invasion in pleural effusion-derived human lung cancer cells

Epithelial-mesenchymal transition (EMT) is implicated in cancer pathological processes, particularly cancer invasion and metastasis. The present study demonstrated that EMT was critical for the metastasic potential of lung cancer cells isolated from a patient. P1 primary lung cancer cells were found to exhibit increased anoikis resistance compared with established A549, H23 and H460 lung cancer cells. Results of migration and invasion assays revealed that the invasion capability of P1 and A549 cells was higher than that of H23 and H460 cells. However, the migration of P1 cells was similar to that of H23 and H460 cells while A549 demonstrated a superior migrating ability. Western blot analysis indicated that while E-cadherin levels in all lung cancer cells were identified as comparable, P1 cells expressed the highest levels of N-cadherin. In the present study, detachment of cells was demonstrated for the first time to stimulate further transition of E-cadherin to N-cadherin. In addition, this obervation was more pronounced in P1 cells. These observations highlight the importance of EMT in cancer metastasis. In order to study the effect of ethnicity on cancer cell behavior, in the future a large number of Thai patient-derived cell lines must be analyzed.