BACKGROUND: Retinoids represent a potentially useful class of drugs in the chemoprevention and treatment of cancer, due to their ability to regulate cell proliferation and differentiation. However, there is controversy in the literature about the effects of all-trans retinoic acid (ATRA) in non- small cell lung cancer (NSCLC). In this study we examined the effects of ATRA on apoptotic death in NSCLC. MATERIALS AND METHODS: Cell proliferation was determined by thymidine incorporation in cultured NSCLC cells. DNA fragmentation was measured in NSCLC cell lines as a marker of apoptosis. The expression of keratinocyte transglutaminase and cytokeratin 10 were measured as markers of squamous differentiation. RESULTS: ATRA inhibited cell proliferation, and induced markers of both apoptosis and squamous differentiation after 24-48 hrs of treatment. CONCLUSIONS: These results indicate the possibility of the early growth-inhibitory and apoptotic effects of ATRA in NSCLC which may result in selection of ATRA-resistant cells.
BACKGROUND:Retinoids represent a potentially useful class of drugs in the chemoprevention and treatment of cancer, due to their ability to regulate cell proliferation and differentiation. However, there is controversy in the literature about the effects of all-trans retinoic acid (ATRA) in non- small cell lung cancer (NSCLC). In this study we examined the effects of ATRA on apoptotic death in NSCLC. MATERIALS AND METHODS: Cell proliferation was determined by thymidine incorporation in cultured NSCLC cells. DNA fragmentation was measured in NSCLC cell lines as a marker of apoptosis. The expression of keratinocyte transglutaminase and cytokeratin 10 were measured as markers of squamous differentiation. RESULTS:ATRA inhibited cell proliferation, and induced markers of both apoptosis and squamous differentiation after 24-48 hrs of treatment. CONCLUSIONS: These results indicate the possibility of the early growth-inhibitory and apoptotic effects of ATRA in NSCLC which may result in selection of ATRA-resistant cells.