Abstract 4969: Enhancing the efficacy of small molecule inhibitor of TRIP13 in prostate cancer using thymoquinone

Abstract Prostate cancer (PCa) is one of the leading causes of cancer-related death in men worldwide. Chemotherapy is effective in the early management of PCa; long-term use activates drug efflux pumps, resulting in resistance and recurrence. In this context, finding the genetic changes causing PCa development could significantly alter therapeutic results. The approach has been to search for specific molecular targets for the selective elimination of cancer cells. Small molecule inhibitor drugs have successfully targeted cancer cell growth and metastasis promotion. Still, small molecule inhibitors bind to multiple molecular targets, including cell surface receptors and other intracellular proteins, thus increasing the risk of toxicity and having a short life span. Therefore, it is crucial to identify new anti-cancer agents that work with small molecule inhibitors to target cancer cells while preventing normal cells. It has been reported that overexpression of the Thyroid hormone receptor interactor 13 (TRIP13) gene, a critical mitosis regulator, plays a role in many cancers. Our analysis using UALCAN (ualcan.path.uab.edu) showed overexpression of TRIP13 in PCa and it plays a role in PCa biology. When TRIP13 is overexpressed, it phosphorylates EGFR and activates a downstream pathway, making cancer cells more aggressive. Recently, DCZ0415, a small molecule TRIP13 inhibitor, was reported to prevent cell proliferation and invasion in several malignancies. Nevertheless, the therapeutic targeting of TRIP13 driving PCa is not well understood. In this study, we demonstrated Thymoquinone (TQ), a natural compound with multifaceted chemo-preventive potential and anti-cancer agent, could reinforce the effect of DCZ0415 in PCa cell lines (DU145 and PC3). PCa cells were treated with TQ or DCZ0415 alone or combined, followed by cell viability (MTT assay) to determine the optimal IC50 values. In a western blot, RT-qPCR analysis, and flow cytometry assays, the combined drug treatment was most effective in blocking TRIP13, inhibiting cell proliferation, and inducing apoptosis. Furthermore, this study determines the combination can upregulate the expression of cell cycle inhibitor (p21WAF1/CIP1), which, in turn, inhibits the expression of CDK4/Cyclin D1 complex, resulting the cell cycle arrest. In addition, TQ, in combination, downregulates the activation of EGFR-dependent PI3K/Akt-1/ERK1/2 and epithelial-mesenchymal transition (EMT) pathways in both cell lines. In conclusion, these findings show thymoquinone's potential to improve DCZ0415 effectiveness and suggest a new promising anti-cancer strategy for treating patients with prostate cancer. Citation Format: Santosh K. Singh, Manoj K. Mishra, Sooryanarayana Varambally, Rajesh Singh. Enhancing the efficacy of small molecule inhibitor of TRIP13 in prostate cancer using thymoquinone. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4969.