RESUMO
BACKGROUND: Curcumin has been isolated from the rhizomes of Curcuma longa. Over the years, it has shown outstanding therapeutic potential in various human disorders, including cancers. OBJECTIVE: The aim is to study curcumin's effects on the apoptosis signaling pathway in the head and neck squamous cell carcinoma (HNSCC) cell line HN5. METHODS: The cytotoxicity of curcumin on HN5 cells were assessed. In addition, HN5 cells were also treated with curcumin to evaluate its effect on the caspase-8, -9, Bcl-2, Bax, and Stat3 gene expressions. RESULTS: The results exhibited that cell viability reduced following curcumin treatment in a concentration- dependent manner. Curcumin treatment caused decreased expression of Bcl2, with simultaneous upregulation of the Bax/Bcl2 ratio. Curcumin increased caspase-9 expression, did not affect caspase-8, and decreased Stat3 expression. The induction of the mitochondria-dependent apoptosis pathway of curcumin happened by modulating the expression of Bcl2 and Bax genes, resulting in the caspase-9 activation. Furthermore, curcumin decreased the expression of the Stat3 in HN-5 cells. CONCLUSIONS: In conclusion, curcumin showed marked anticancer effects in the HN-5 cell line by modulating Stat-3; Bax/Bcl-2 expression in vitro.