Alexander Cartagena-Rivera, Ph.D., Tenure-Track Investigator, Chief of the Section on Mechanobiology National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health

Speaker:

Alexander Cartagena-Rivera, Ph.D.

Tenure-Track Investigator, Chief of the Section on Mechanobiology

National Institute of Biomedical Imaging and Bioengineering

National Institutes of Health

Faculty Host: Ryan Stowers

Title: Aberrant glycosylation regulates membrane surface architecture and viscoelasticity of pancreatic cancer cells

Abstract: 

The cellular glycocalyx plays a crucial role in making pancreatic cancer one of the deadliest malignancies globally. It complicates early detection and reduces the effectiveness of conventional therapies. In pancreatic cancer, the components of the glycocalyx are often upregulated or abnormally glycosylated, promoting tumor progression through immune evasion, enhanced metastasis, and drug resistance. While these biochemical effects are known, the biophysical impact of the glycocalyx on cancer cells is less understood. In our study, we explored the structural and biomechanical effects of modifying the glycocalyx architecture in pancreatic cancer cells using various chemical compounds. We employed a recently developed Atomic Force Microscopy nanomechanical mapping method to visualize cellular mechanical heterogeneities in a high spatiotemporal context. Our new approach allows for the viscoelastic inversion of high-resolution spatiotemporal data at rates which are orders of magnitude faster (more than 37,386-fold) than optimizing a traditional rheological model for each pixel. Then, we investigated the architectural and biophysical effects of glycocalyx architectural modulation in pancreatic cancer cells. Perturbations of hyaluronic
acid (HA), sialic acid (SA), mucins, and N-glycans through enzymatic treatments led to significant architectural remodeling of the cell surface. Interestingly, removal of SA and mucins resulted in a softer and more fluid cell surface, while removal of HA softened and increased viscosity. In addition, preliminary cytokine expression results suggested that SA removal leads to a pronounced pro-inflammatory response (IL-2, IL-8, INF-γ among others) of human cytotoxic CD8+ T Lymphocytes, greater than removing other glycocalyx components. 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 SA deposition. Our findings suggest that the glycocalyx of human pancreatic ductal adenocarcinoma cells fundamentally regulate extracellular surface architecture, mechanical properties, composition, and function, thereby promoting tumor progression and metastasis by acting as a physical barrier to antitumor responses.

Bio:

Dr. Alexander X. Cartagena-Rivera received a Ph.D. in Mechanical Engineering from Purdue
University in 2014. Dr. Cartagena-Rivera joined the National Institute of Biomedical Imaging and
Bioengineering at the National Institutes of Health as an Earl Stadtman Tenure-Track
Investigator position in 2019. He is now chief of NIBIB’s Section on Mechanobiology, where he
and his lab staff continue work on understanding cellular and tissue molecular-mechanical
regulation and development of advanced atomic force microscopy technologies for cancer
biology and hearing research.