Abstract P005: SLC38A5 characterization and its tumor promoting role in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal and aggressive cancers. Based on the Human Protein Atlas database, solute carrier 38A5 (SLC38A5) is significantly upregulated in PDAC and correlates with poor patient survival. SLC38A5 is a Na+-coupled, electroneutral amino acid transporter that transports glutamine, serine, glycine, and methionine that are essential for glutaminolysis and one-carbon metabolism pathways on which cancer cells are dependent. Furthermore, SLC38A5 is a c-Myc target and induces macropinocytosis. Thus, these attributes of SLC38A5 in cancer cells makes it a favorable contribution to their tumor-promoting gene expression programs. Using real-time PCR and Western blotting, we validated the expression status of SLC38A5 in PDAC cell lines, patient derived xenografts (PDX), and organoids. Using radiolabeled serine uptake, we also confirmed that PDAC cell lines express functional SLC38A5. To investigate the tumor promoting role of SLC38A5, shRNA-mediated knockdown of SLC38A5 was performed in BxPC-3 and HPAF-II human PDAC cell lines. After validating SLC38A5 knockdown using real-time PCR and radiolabeled serine uptake, colony formation and transwell invasion assay were performed using the knockdown cells and non-targeting controls (NTC). Interestingly, SLC38A5 knockdown suppressed the colony formation ability as well as the invasion capacity in both cell lines, suggesting the tumor promoting role of SLC38A5. To extrapolate the in vitro data further, we performed subcutaneous xenograft using SLC38A5-silenced BxPC-3 and HPAF-II cells into the athymic nude mice. Interestingly, we found that SLC38A5 knockdown cells grew slower, as evidenced by smaller tumor weight, further validating our in vitro data. Our future work involves extrapolating these data in the KPC (Kras, p53, and PDX-1-Cre) spontaneous mouse model of PDAC and elucidating its mechanism of upregulation. Citation Format: Tyler J. Sniegowski, Vadivel Ganapathy1, Yangzom Bhutia. SLC38A5 characterization and its tumor promoting role in pancreatic ductal adenocarcinoma. [abstract]. In: Proceedings of the AACR Special Conference: Precision Prevention, Early Detection, and Interception of Cancer; 2022 Nov 17-19; Austin, TX. Philadelphia (PA): AACR; Can Prev Res 2023;16(1 Suppl): Abstract nr P005.