PhD Scientific Days 2026

Poster Session 3.J - Theoretical and Translational Medicine

Modulation of the endothelial barrier function during ICAM-1-mediated mechanotransduction

Name of the presenter

Harsányi, Laura

Institute/workplace of the presenter

Semmelweis University, Department of Biophysics and Radiation Biology

Authors

Laura Harsányi¹, Éva Gráczer¹, Katalin Pászty¹, Andrea Varga¹
1: Department of Biophysics and Radiation Biology, Semmelweis University

Text of the abstract

• Introduction: Dynamic changes of the barrier-maintaining endothelial adherens junctions (AJ) allow the passage of leukocytes in inflammation through the endothelial monolayer and cancer cells use the same route during metastasis. We found previously that the protein kinase BRAF contributes to the weakening of endothelial AJs, and this supports melanoma metastasis in mice.
• Aims: Our aim was to explore potential treatments converging on the actin cytoskeleton to strengthen the endothelial barrier under inflammatory conditions, which might reduce the likelihood of metastasis.
• Methods: Migrating cells exert forces on the endothelium through cell surface adhesion molecules, such as intercellular adhesion molecule ICAM-1. To study ICAM-1-mediated mechanotransduction, we applied ICAM-1-antibody-coated magnetic beads and exerted about 40 pN force on the endothelium by using a permanent magnet. Permeability of the endothelium was determined by quantifying the area of intercellular gaps. Endothelial cell-cell adhesions were analyzed by VE-cadherin and actin staining. Adhesion of HCT116 colon carcinoma cells to the endothelium was also determined.
• Results: We found that force exertion through ICAM-1 results in the reorganization of AJs and is accompanied by intercellular gap formation. Both changes were reduced either by using BRAF siRNA or a combination of a TPRV4 channel, an S1P2 receptor antagonist and an S1P1 receptor agonist. The size of apical filopodia on the endothelium was not increased in BRAF siRNA-treated endothelial monolayer upon mimicking the adhesion of cancer cells by using ICAM-1-antibody coated beads. The adhesion of HCT116 cells on the endothelium was reduced by both BRAF siRNA treatment and the application of the previously mentioned treatment combinations.
• Conclusions: Both endothelial BRAF knockdown and the concerted action on S1P receptors and TRPV4 channel reduced HCT116 colon cancer cell adhesion on the endothelium and strengthened the endothelial barrier.
• Funding: This research was supported by the SE250 Excellence PhD Scholarship.