Abstract B040: Combined treatment and metabolomics reveal mechanism underlying the synergy of ribitol and shikonin against breast cancer

Abstract Background: Breast cancer is the most common cancer and one of the leading causes of cancer-related death. Current treatments are often associated with severe side effects, and cancer cells often develop resistance. Therefore, it is imperative to identify new treatment options. In the present study, we investigated whether the metabolite ribitol enhances cytotoxic effect of shikonin against breast cancer in vitro. Methods: Here, we screened a panel of small molecules targeting energy metabolism against breast cancer. Cell viability and synergistic studies on breast cancer cells was evaluated by ATP CellTiter-Glo assay. Growth of cancer cells was monitored by MuviCyte™ live-cell Imaging System. Apoptosis was analyzed by Real time glo annexin-V assay and western blotting. Finally, we applied global untargeted metabolomic analysis after ribitol and shikonin treatment for mechanism of synergy. Results: The results revealed that the combination of ribitol and shikonin has significant synergistic effect when compared to shikonin alone on MCF-7 cells. A significant (p<0.01) increase in percentage (56%) of apoptotic cells was detected in combined treatment group compared to 16%, 38% in the ribitol and shikonin single-treatment group, respectively. The combined ribitol and shikonin treatment leads to arrest of cell proliferation (40%) significantly (p<0.01) compared to untreated cells and induction of apoptosis by up-regulation of p53 (p<0.05) and down-regulated expression of c-Myc (p<0.01), Bcl-xL (p<0.001) and Mcl-1(p<0.05). Data from metabolomic analysis support the notion that inhibition of Warburg effect is involved in shikonin-induced cell death which is likely further enhanced by dysregulated glycolysis and TCA cycle afflicted by ribitol treatment. Conclusion: The present study demonstrates that the metabolite ribitol enhances cytotoxic effect mediated by shikonin against breast cancer in vitro. Citation Format: Ravi Doddapaneni. Combined treatment and metabolomics reveal mechanism underlying the synergy of ribitol and shikonin against breast cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2025 Oct 22-26; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2025;24(10 Suppl):Abstract nr B040.