Abstract 4727: Exploring glycosylation as a barrier to drug therapy in lymphoma: unlocking new therapeutic potential

Background: Lymphoma, a cancer more common in younger males, poses challenges in developing treatments with precise target selectivity. Mucin, a glycosylated protein overexpressed in tumor cells, forms a barrier shown elsewhere to impede drug effects. For example, we previously demonstrated in pancreatic cancer models that the inhibition of mucin glycosylation improved treatment outcomes in vitro and in vivo. This approach remains unexplored in lymphoma. This study examines the extent to which mucin glycosylation impacts the intracellular uptake and effectiveness of lymphoma therapeutics in vitro. We hypothesize that glycosylation functions as a cellular barrier limiting cellular access to model agents and subsequent drug effects. Methods: The U-937 human lymphoma cell line (ATCC CRL-1593.2) was cultured in RPMI-1640 medium supplemented with 5% fetal bovine serum (FBS). Cells were seeded in 24-well plates and exposed to a glycosylation inhibitor (benzyl-α-GalNAc). After a required incubation period, the cells were exposed to a fluorescently tagged anti-MUC1 antibody (used to probe the degree of cell access to molecular entities in the presence and absence of the glycation mesh). Antibody uptake was analyzed using a fluorescent microplate reader. The functional drug effects of pre-exposing U-937 cells to the glycosylation inhibitor were initially assessed through cell viability experiments (using Quadcount™), with follow-up studies using a fluorometric assay. Results: At 1 hour, cells that were pre-exposed to the glycosylation inhibitor demonstrated significantly higher uptake of the anti-MUC1 antibody compared to untreated cells (p = 0.0266), suggesting enhanced drug delivery in the early stages. Future studies will investigate whether the uptake is time-dependent, favoring prolonged cellular exposure to the antibody. Preliminary data shows that the pre-exposure of U-937 cells to benzyl-α-GalNAc enhanced the effect of imatinib significantly when compared to imatinib alone (P= 0.0240). The impact of cellular glycosylation on the effect of additional therapeutic agents is currently under investigation. Conclusions: Targeting mucin glycosylation with benzyl-α-GalNAc enhanced anti-MUC1 antibody uptake. The improved cell kill observed with the inhibitor-imatinib combination further underscores the promise of this strategy in overcoming drug resistance in lymphoma. Citation Format: Shayan Mosaffa, Thao Nguyen, Nasr Issa, Robert B. Campbell. Exploring glycosylation as a barrier to drug therapy in lymphoma: unlocking new therapeutic potential [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4727.