Abstract B025: A multi-omic, spatial approach using patient prostatectomies to identify actionable drug targets for combatting prostate cancer health disparities

Abstract

Abstract Prostate cancer (PC) is the most commonly diagnosed cancer among African American men (AA) and continues to be the largest difference in absolute incidence and cancer-specific deaths between AA and Caucasian men (CA). AA have a 70% higher incidence of PC than CA and over a 2 times higher mortality rate. Among men undergoing prostate biopsy In an equal access setting (i.e. the VA), AA are ~50% more likely to have PC and ~80% more likely to have high-grade PC than CA. The frequency of PC-associated genetic alterations and differences in oncogene expression in PCs is altered from CA and AA. While social economic status and environmental factors may play a role in PC health disparities, there are inherent genetic/molecular differences that account for the differences in PC outcomes between CA and AA. We sought to test our hypothesis that there is a subset of actionable gene products that are essential for enhanced PC progression in AA. A focused and clinically informed CRISPR knockout screen was conducted to identify and functionally validate race-specific actionable genes that contribute to the increased risks of fatal PC in AA. The CRISPR screen was designed leveraging a radical prostatectomy transcriptomic dataset from the Durham VA Medical Center that was linked with long-term clinical outcome data. This unique dataset consists of ~600-profiled radical prostatectomy samples of which over 50% were from AA patients. A Cox hazard analysis revealed differentially expressed genes (DEGs) which are positively associated with an increased risk of metastatic disease unique to AA PC patients. To identify drug-targetable genes, these DEGs were filtered against the drug-gene interaction database (DGIdb). This approach yielded 89 genes positively associated with an increased risk of metastatic outcome in AA and 236 genes in CA only. The CRISPR KO screen resulted in 19 genes significantly depleted genes. Of these 19 hits, 11 genes were genes associated with metastasis in AA, while 8 hits were CA genes, with 5 of 11 AA hits having documented small molecule inhibitors. To further prioritize our hits, we have conducted a spatial transcriptomic analysis of radical prostatectomy tissues from AA and CA PCs. By standard H and E staining these tumors look quite similar. But spatial analysis of AA compared to CA tissues revealed differences in immune cells and cells associated with the tumor microenvironment. This integrative multi-omic approach reveals new cell identities that may contribute to the aggressive pathogenicity of PC in AA compared to CA. CRISPR models and small molecule inhibitors of our top candidates will be used to investigate the druggability of these DEGs. This study lays the groundwork for potential therapeutics targeted toward PC in AA men. Citation Format: Felipe Segato Dezem, Aiza Akhtar, Arjumand Wanj, Sunyoung You, Hannah Chasteen, So Young Kim, Jasmine Plummer, Everardo Macias. A multi-omic, spatial approach using patient prostatectomies to identify actionable drug targets for combatting prostate cancer health disparities [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr B025.