Abstract B072: A novel selective glycolysis inhibitor, SGI-1553, targets adenosine kinase in advanced prostate cancer

Abstract Introduction: Prostate cancer (PCa) is the most commonly diagnosed cancer in men in the United States and the second leading cause of cancer related deaths. A new therapeutic strategy that can treat a large population of patients is necessary. One emerging direction is cancer metabolism; however, targeting metabolic pathways poses a toxicity risk due to these pathways being active in both benign and malignant cells. Prior studies demonstrate that more advanced stages of PCa are more dependent on glycolysis. We have developed a compound, SGI-1553, which selectively inhibits the early steps in glycolysis in prostate cancer cells and patient-derived xenografts (PDXs), but does not affect benign cells at therapeutic levels. However, the exact target of this compound was not known. The purpose of this study was to identify the target of SGI-1553. Methods: Lysates from LNCaP and LNCaP95 cells were treated with SGI-1553 or DMSO. Lysates were then exposed to increasing temperatures, digested, and run through mass spectrometry. Proteins showing a thermal shift in the denaturing temperature when exposed to SGI-1553 were identified. Protein crystallography of the lead target and compound were then performed. Enzyme assays of the recombinant target protein exposed to increasing doses of SGI-1553 were run. The target was knocked down in LNCaP and LNCaP95 cells using a shRNA lentiviral construct. RNA-seq on control and knockdown cells was then performed followed by GSEA pathway analysis. Results: Thermal shift mass spectrometry revealed that the target of SGI-1553 is adenosine kinase (ADK). Treatment with SGI-1553 resulted in a 5˚C thermal shift to the right for ADK when compared with DMSO. Crystallography of recombinant ADK with SGI-1553 demonstrated binding of SGI-1553 within the adenosine pocket of ADK. Enzyme assays of recombinant ADK showed increased activity of ADK above baseline with increasing concentrations of SGI-1553 (15-18% max increase). In shADK cells compared with control cells, GSEA analysis demonstrated upregulation of Myc targets-V1 and V2, E2F targets, and fatty acid metabolism; downregulation was seen in hypoxia and epithelial to mesenchymal transition pathways. These same pathways were up and downregulated in human PCa xenografts that were resistant to the effects of SGI-1553. Conclusion: SGI-1553 binds to and activates ADK in PCa cells that are responsive to the inhibitory growth effects of SGI-1553. shADK cells displayed similar regulation of pathways on GSEA analysis as human PDXs that are unresponsive to SGI-1553 in vivo. Adenosine kinase has numerous roles in cells including energy regulation, nucleotide pool regulation, and regulation of transmethylation. Our group is currently examining the effects of overexpressing and knocking down ADK expression in prostate cancer cell lines on glycolysis, proliferation, and methylation. Identifying ADK as the target and examining its biological effects in prostate cancer will allow us to use structure-guided drug development to create more potent compounds for use in prostate cancer therapy. Citation Format: Shihua Sun, Ilsa Coleman, Lyssa Weible, Kathryn Soriano Epilepsia, Mika Munari, Peter Nelson, Robert Moritz, Scott Lovell, Stephen Plymate, Wesley Van Voorhis, Kayode K. Ojo, Cynthia Sprenger. A novel selective glycolysis inhibitor, SGI-1553, targets adenosine kinase in advanced prostate cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Innovations in Prostate Cancer Research and Treatment; 2026 Jan 20-22; Philadelphia PA. Philadelphia (PA): AACR; Cancer Res 2026;86(2_Suppl):Abstract nr B072.