Cytotoxic effects of grape seed oils on cancer cells

Grape seed oils represent a natural resource of considerable interest due to their content of bioactive compounds and their role in environmental sustainability, as they are sourced from the winemaking industry’s by-products. Red (RGSO) and white (WGSO) grape seed oils have previously proved to improve glucose uptake and utilization by cultured liver cells (1), a process closely linked to cellular metabolism and proliferation. Given the growing interest in utilizing natural substances for the prevention and treatment of chronic diseases, including cancer, we examined the potential cytotoxic impact of RGSO and WGSO on HepG2 (human hepatocellular carcinoma) and CaCo-2 (human colorectal adenocarcinoma) cells, the latter also induced to spontaneous differentiation in vitro. Specifically, our work aimed to evaluate the potential involvement of apoptosis and impaired autophagic flux. Dose-response curves revealed that, unlike WGSO, RGSO exerted cytotoxic effects selectively on CaCo-2 cells, while the viability of differentiated CaCo-2 cells remained unaffected by either oil at all tested concentrations. Responsive cells were, subsequently, treated with the oils at their respective IC50 values. Live cell flow cytometry was employed to determine the proportion of cells positive for acridine orange, DCHF-DA, FITC-AnnexinV and propidium iodide. Western blot analysis was performed to quantify the expression levels of apoptotic regulators (Bax, Bcl-2, and Bcl-XL), autophagic markers (Beclin-1, p62, LC3-I and LC3-II), and cytoprotective proteins (Hsp60 and Hsp90). Overall, these findings indicate that RGSO and WGSO exert distinct death-promoting effects in cancer cells, primarily through reactive oxygen species generation and modulation of the autophagic pathway, highlighting their potential relevance as a source of bioactive compounds in metabolism-related anticancer research.