Local mechanobiological disruption in solid tumor-driven vascular permeability: A competition between mechanical vs chemical stimuli

The tumor microenvironment imposes complex biochemical and biomechanical constraints on microvasculature, contributing to aberrant tumor blood vessels, characterized by abnormal endothelial proliferation, disrupted cell-to-cell junctions and increased permeability. While vascular normalization strategies have traditionally focused on biochemical modulation, the role of mechanical forces in endothelial dysfunction remains unclear. Here, we used a microfluidic platform to dissect the mechanobiological impact of two distinct solid tumor models -pancreatic ductal adenocarcinoma (PANC-1) and lung adenocarcinoma (A549)-on three-dimensional embedded endothelial vessels. Our findings reveal that PANC-1 spheroids exert significant mechanical forces, expanding vessel diameter and disrupting endothelial barrier integrity via cellular contractility. Conversely, A549 spheroids contribute to vascular destabilization through biochemical modulation, primarily via extracellular matrix degradation and inflammatory secretomes, leading to an altered and heterogeneous endothelial permeability. Proteomic analysis of both tumor cell lines highlights distinct pathways involved in endothelial remodeling: cytoskeletal alterations and consequent stresses in pancreatic ductal adenocarcinoma, while extracellular matrix remodeling and pro-inflammatory microenvironment are found in lung adenocarcinoma. These insights underscore the necessity of tumor-specific vascular normalization strategies, combining mechanobiological and biochemical approaches to restore endothelial barrier function. Our locally controlled microfluidic approach provides a versatile platform for evaluating innovative therapeutic strategies targeting tumor-specific vasculature. STATEMENT OF SIGNIFICANCE: This study highlights the often-overlooked role of tumor-derived mechanical forces in vascular dysfunction. Within the tumor microenvironment, different tumor types disrupt the endothelial barrier through distinct, tumor-specific mechanisms, leading to varied patterns of vessel instability. Using confocal microscopy, we achieved spatially resolved analysis of local endothelial barrier damage, distinguishing focal from diffuse permeability changes. A 3D microfluidic platform was developed to replicate tumor endothelium interactions, combining live imaging, morphometric and biochemical assays, and proteomic profiling. This integrative model offers a versatile tool for evaluating drug responses under controlled mechanochemical conditions, supporting the development of personalized vascular-targeted therapies.