In vitro anticancer activity of a pentacyclic triterpenoid via the mitochondrial pathway in bone-invasive oral squamous cell carcinoma

CONTEXT: Oral cancer is the most dreadful cancer worldwide with a 5-year survival rate of approximately 50%. Anticancer therapies such as chemotherapy and radiotherapy result in severe side effects. AIM: We aimed to evaluate the in vitro anticancer activity of Asiatic acid (AA) on bone-invasive oral squamous cell carcinoma (BHY) cell line. SETTINGS AND DESIGN: This was an in vitro laboratory setting. MATERIALS AND METHODS: BHY cell lines were used for the experiment. Confocal microscopy was used to observe cellular alterations. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to determine the IC50 concentration of AA and flow cytometry to analyze the percentage of cells in each phase of the cell cycle post treatment. Immunoblot assays and semiquantitative reverse transcriptase-polymerase chain reaction (rt-PCR) were used to study the expression level of genes involved. STATISTICAL ANALYSIS USED: Student's t-test and one-way analysis of variance were used for statistical analysis. RESULTS: IC50 concentration of AA was 15.6 μM. On flow cytometry analysis, treatment with 15.6 μM and 31.25 μM of AA for 24 h increased the percentage of cells in the G2/M phase to 45.63% and 53.12%, respectively, compared to 9.62% in control group. Immunoblot analysis and semiquantitative rt-PCR demonstrated an upregulation of p53, cyclin-dependent kinase inhibitors (p21 and p27), caspase-3, caspase-9, cytochrome c and Bax in a time-dependent manner and downregulation of cyclins and anti-apoptotic protein Bcl-2 (**P < 0.05, ***P < 0.001 versus control) post AA treatment. CONCLUSION: AA induces apoptosis via the mitochondrial-dependent pathway and causes cell cycle arrest at the G2/M phase in BHY cell line.