Abstract 7200: Non-cytotoxic inhibition of nuclear encoded mitochondrial protein MAGMAS resensitize treatment resistant prostate cancer cells to taxane therapy

Abstract Metastatic prostate cancer (PCa) is the leading cause of PCa-associated deaths and one of the leading causes of cancer mortality in men. Novel therapeutics, such as Prostate Specific Membrane Antigen (PSMA) ligand therapy, are emerging as effective treatment strategies for metastatic prostate cancer. However, most men succumb to Metastatic Castration Resistant Prostate Cancer (mCRPC) due to treatment resistance. MAGMAS, a 13. 8 kDa mitochondrial protein, imports nuclear-encoded mitochondrial proteins into the mitochondrial matrix. MAGMAS is overexpressed in several aggressive tumors, such as breast cancer, glioblastoma, and prostate cancer. When overexpressed, MAGMAS plays a role as a cytoprotective protein by acting as a reactive oxygen species (ROS) scavenger that maintains sufficient ROS levels to promote cell proliferation but below the threshold levels that could lead to apoptosis. This study was designed to investigate the pro-survival and therapy-resistance functions of MAGMAS in treatment-resistant PCa cells. Predictively, we observed that the docetaxel (DTX) -resistant PC3-DR and DU145-DR PCa cell lines expressed significantly higher levels of MAGMAS compared to their drug-sensitive parental cell lines. We hypothesized that inhibiting Magmas reduces the aggressive properties of highly proliferative DTX-resistant metastatic PCa cell lines and re-sensitizes them to DTX. MAGMAS knockdown in DTX-resistant PC3 and DU145 cells in the presence of increasing DTX treatments enhanced sensitivity to DTX. Consistent with these results, pharmacological inhibition of MAGMAS with the novel BT#9 inhibitor in combination with increasing DTX concentrations also enhanced sensitivity to DTX in these cell lines. Additional studies using cell migration/invasion assays and tumor-sphere formation assays are underway to further establish MAGMAS as a potential therapeutic target to attenuate the aggressive properties of chemo-resistant PCa cells. Lastly, we will investigate the diagnostic potential of MAGMAS as a biomarker for advanced PCa and BT#9 as an imaging/therapeutic-specific agent for treatment-resistant tumors. Citation Format: Alfonso Duran, Kristen Whitley, Krystal Santiago, Adil Mohammed, Carlos Casiano, Bhaskar Das, Frankis Almaguel. Non-cytotoxic inhibition of nuclear encoded mitochondrial protein MAGMAS resensitize treatment resistant prostate cancer cells to taxane therapy abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 7200.