Investigation of the effect of betanin on Wnt/β-catenin and PI3K/AKT/mTOR signalling pathways in Saos-2 osteosarcoma cell line

Objective: This study aimed to determine the effect of red beet (Beta vulgaris) component betanin on Wnt/β-catenin and PI3K/AKT/mTOR signaling pathways in Saos-2 human osteosarcoma cells. Material and Methods: The osteosarcoma cell line Saos-2 was used in this study. In order to determine the effect of betanin on cell viability, a dose range of 25- 400 μM was applied and the cell viability was evaluated after 24- 48 hours using the MTT assay. The proliferation curve obtained as a function of time and dose was analysed to determine the appropriate dose for apoptosis and RT-PCR studies. Apoptosis was detected at these selected doses using the Muse Cell Analyzer with the Muse Annexin V Kit. Expression of genes in the PI3K/AKT/mTOR and Wnt/β-catenin signalling pathways was measured at the mRNA level using real-time PCR. Statistical analyses were performed using the independent sample t-test (p<0,05) in the IBM SPSS software (v25). Results: The dose of betanin that inhibited 50% of Saos-2 cells was 330 μM. Furthermore, betanin treatment was found to increase apoptosis in Saos-2 cells in a dose-dependent manner. In addition, betanin treatment significantly decreased PI3K, AKT, mTOR and β-catenin mRNA expression while significantly increasing GSK-3β mRNA expression. Conclusion: Betanine suppresses proliferation and induces apoptosis in osteosarcoma cells and may also induce tumour suppression in vitro via the Wnt/β-catenin and PI3K/AKT/mTOR signalling pathways. Keywords: Betanin, Osteosarcoma, Apoptosis, RT-PCR, PI3K/AKT/mTOR, Wnt/β-catenin.