Abstract 402: Aneuploidy-associated SQLE gain promotes prostate cancer aggressiveness by altering lipid metabolism

Abstract Prostate cancer (PCa) is the second leading cause of cancer-related death in men in the US. Epidemiology studies on primary PCa cohorts in Physicians' Health Study and Health Professionals Follow-up Study (PHS and HPFS) have shown that high levels of whole-genome aneuploidy, featured by imbalanced chromosome numbers, correlate with lethal progression in PCa. However, details of the mechanisms of how aneuploidy drives PCa aggressiveness are still unclear. Here, we used the case of chromosome 8q (chr 8q, the long arm of chr 8) gain to study aneuploidy-associated prostatic malignancies. Chr 8q gains are the most frequent gain events that occur in approximately 23% of PCa cases. By using the PHS and HPFS cohorts, we modeled the increased expression of each gene located on chr 8q, for predicting the risks for lethal progression, and obtained each corresponding gene’s odds ratio (OR). By ranking the ORs, we revealed that a cholesterol biosynthesis gene, squalene monooxygenase (SQLE), is one of the top associators with lethal progression, amongst all chr 8q genes. SQLE plays a pivotal role in cholesterol synthesis. Previous lymphoma studies have shown that loss of SQLE contributes to cholesterol auxotrophy, and squalene build-up protects against oxidative cell death. In our experimental study, we have used normal and cancerous TMPRSS2-ERG-driven organoid models and found that over-expression of SQLE promotes formation of invasive structures and proliferation in cancer organoids. Interestingly, overexpression of SQLE decreased the protein levels of TMPRSS2-ERG, which appeared to be independent of androgen receptor levels. We also utilized the TMPRSS2-ERG positive VCaP cell line, which harbors gains of SQLE gene copies. We found that knocking down SQLE expression significantly upregulated ERG protein levels. Our recent study has shown that ERG (or other ETS) positive prostate cancers have a strong correlation with downregulation of fatty acid metabolism signature. We speculate that gain of SQLE can drive aggressiveness of prostate cancer by modulating lipid metabolism for growth and migration. Inhibition of SQLE could translate to better clinical outcomes regarding prostate cancer lethality. Citation Format: Thomas Walter Janas, Xiaofeng A. Su, Konrad H. Stopsack, Daniel R. Schmidt, Duanduan Ma, Zhe Li, Kathryn L. Penny, Tamara L. Lotan, Lorelei A. Mucci, Matthew G. Vander Heiden, Elise DeArment, Angelika Amon, Paul A. Scheet. Aneuploidy-associated SQLE gain promotes prostate cancer aggressiveness by altering lipid metabolism [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(6_Suppl):Abstract nr 402.