Abstract A049: Sialic acid depletion leads to profound remodelling of glycocalyx architecture and mechanics in pancreatic cancer cells

Abstract Pancreatic cancer remains one of the most lethal malignancies due in part to issues with early detection and high levels of drug resistance. Partly to blame for these issues is the glycocalyx, an extracellular structure found on most cells that is aberrantly glycosylated and has overexpressed biopolymers in cancerous cells. In pancreatic cancer, this includes higher levels of mucin expression, increased sialylation, and more hyaluronic acid production. Of note regarding sialic acid, numerous studies suggest that aberrant sialylation can affect various pathways in cancer, including immune attenuation, enhanced metastasis, and altered apoptosis. Although there is considerable work detailing the biochemical role of these glycocalyx modifications in pancreatic cancer, we sought to understand their role in the architecture and mechanical properties of the tumor cell. The mechanical profiling of cells is an emerging field, yet the role of the glycocalyx from a mechanical standpoint remains less understood. To help elucidate these properties, we enzymatically degraded different components of the glycocalyx commonly found to be aberrantly expressed in pancreatic cancer (e.g., N-glycans, sialic acids, mucins, and hyaluronic acid) and visualized changes in the structure of the membrane via atomic force microscopy (AFM), confocal fluorescence microscopy and scanning electron microscopy. We observed a profound reduction in microvilli density and thickness that was the most consistent with sialic acid removal across all three cell lines investigated. Using AFM-based nanomechanical mapping, we investigated changes in cell surface mechanics and observed a significant reduction in the viscoelastic properties (elastic storage and viscous loss moduli) when removing sialic acid. This observation suggests that the cell surface softens and fluidizes in response to desialylation. Similarly, removal of mucins also led to reduced microvilli density, softening, and fluidization in pancreatic cells - to a degree that was matched by removal of sialic acids. Lastly, a glycomics study also revealed unique changes in the structure of N- and O-glycans, with significantly more heterogeneity in the structure of N-glycans on pancreatic cancer cells, and O-glycans showing a particularly higher degree of sialic acid deposition. Future studies will attempt to translate in vitro observations of de-glycosylation with patient tissue viscoelastic data to highlight the role of glycocalyx modulation at an intratumoral level to better understand chemo and immune therapy resistance, with the goal of determining the therapeutic potential of aberrant sialylation as a target for novel therapies. Citation Format: Andrew Massey, Krishna M. Manchuri, Stephen Behrman, Parastoo Azadi, Alexander Cartagena-Rivera. Sialic acid depletion leads to profound remodelling of glycocalyx architecture and mechanics in pancreatic cancer cells [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research—Emerging Science Driving Transformative Solutions; Boston, MA; 2025 Sep 28-Oct 1; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2025;85(18_Suppl_3):Abstract nr A049.