Potencial terapêutico dos inibidores de Smoothened em Carcinoma Escamocelular Oral

Abstract

INTRODUCTION: Oral Squamous Cell Carcinoma (OSCC) is the most common malignant tumor of the head and neck. However, pharmacological inhibition of pathways related to OSCC tumorigenesis, such as Hedgehog (HH) pathway, has demonstrated minor progress. Interestingly, Smoothened (SMO) inhibition has been shown to be a promising therapeutic target in cancer. AIM: The aim of this study was to investigate the effects of vismodegib and itraconazole on HH genes expression (PTCH1, SMO and GLI1), cell cycle and cell death in OSCC cells. METHODS: Alamar Blue assay was used to assess citotoxicity of vismodegib and itraconazole on cancer cell lines after 72h treatment and additional treatments were perfomed in CAL27 for 6h, 12h, 24h, 48h and 72h. The expression of HH signaling components before and after treatment with vismodegib and itraconazole in both 25 and 50 μg/mL concentrations was evaluated by qPCR. Cell cycle and apoptosis were evaluated by the flow cytometer after 72h treatment with vismodegib and itraconazole (50 μg/mL). RESULTS: HH signaling was activated in OSCC cell lines CAL27, SCC4, SCC9 and HSC3. SMO inhibitors have not demonstrated promising citotoxicity in OSCC cells, however vismodegib and itraconazole (50 μg/mL) significantly reduced cell viability after 48h treatment. The expression of PTCH1, SMO and GLI1 was descreased after treatment with vismodegib and itraconazole for 24h. Furthermore, CAL27 cells exhibited alterations in morphology, cell size (FSC) and cell granulosity (SCC). An increase in Sub-G1 population was observed after treatment and both inhibitors induced apoptosis after 72h treatment. CONCLUSIONS: HH signaling is activated in OSCC cell lines. SMO inhibitors (vismodegib e itraconazole) reduced HH genes expression on CAL27 cells. Vismodegib and itraconazole reduced cell viability and changed cell morphology. Moreover, both inhibitors induced DNA fragmentation and apoptosis in CAL27 cells.