The study aimed to evaluate the anticancer potential of hinokitiol in treating oral cancer by using in vitro models and examining its interaction with the Pim-1 protein through in silico methods. Hinokitiol was applied to KB-1 oral squamous carcinoma cells, where the half-maximal inhibitory concentrations (IC50) was determined. Morphologic changes in treated cells were observed using phase contrast microscopy, while acridine orange/ethidium bromide (AO/EB) staining was used to assess nuclear changes and apoptosis. Flow cytometry was employed to analyze the cell-cycle progression. Given the high expression of Pim-1 in oral squamous carcinoma cells, molecular docking and simulation were performed to evaluate hinokitiol's binding affinity and stability with the Pim-1 protein. To compare its effects, hinokitiol was also tested on non-cancerous pre-adipocytes (3T3-L1), providing insights into its selective cytotoxicity between healthy and cancerous cells. Hinokitiol treatment resulted in cytotoxic effects on KB-1 oral squamous carcinoma cells, with an IC50 of 30 µg/mL after 24 and 48 hs of exposure. Morphologic studies showed reduced cell population and density. In contrast, hinokitiol exhibited lower toxicity and caused fewer morphological changes in non-cancerous 3T3-L1 pre-adipocytes. Apoptosis was confirmed through acridine orange/ethidium bromide staining, while flow cytometry revealed cell-cycle arrest in the Synthesis phase (S) and Gap 2 phase/ Mitosis Phase (G2/M) phases. Molecular docking showed strong binding of hinokitiol to Pim-1, and simulations confirmed the interaction's stability. These findings suggest hinokitiol selectively targets cancer cells and effectively inhibit Pim-1, supporting its potential as an oral cancer treatment.
Keywords: Hinokitiol; Molecular dynamics; Oral cancer; Pim-1.
© 2024. The Author(s), under exclusive licence to The Society of The Nippon Dental University.