Lung cancer is a leading cause of death worldwide, with only a fraction of patients responding to immunotherapy. The correlation between increased T-cell infiltration and positive patient outcomes has motivated the search for therapeutics promoting T-cell infiltration. While transwell and spheroid platforms have been employed, these models lack flow and endothelial barriers, and cannot faithfully model T-cell adhesion, extravasation, and migration through 3D tissue. Presented here is a 3D chemotaxis assay, in a lung tumor-on-chip model with 3D endothelium (LToC-Endo), to address this need. The described assay consists of a HUVEC-derived vascular tubule cultured under rocking flow, through which T-cells are added; a collagenous stromal barrier, through which T-cells migrate; and a chemoattractant/tumor (HCC0827 or NCI-H520) compartment. Here, activated T-cells extravasate and migrate in response to gradients of rhCXCL11 and rhCXCL12. Adopting a T-cell activation protocol with a rest period enables proliferative burst prior to introducing T-cells into chips and enhances assay sensitivity. In addition, incorporating this rest recovers endothelial activation in response to rhCXCL12. As a final control, we show that blocking ICAM-1 interferes with T-cell adhesion and chemotaxis. This microphysiological system, which mimics in vivo stromal and vascular barriers, can be used to evaluate potentiation of immune chemotaxis into tumors while probing for vascular responses to potential therapeutics. Finally, we propose translational strategies by which this assay could be linked to preclinical and clinical models to support human dose prediction, personalized medicine, and the reduction, refinement, and replacement of animal models.
Keywords: chemotaxis; complex in vitro models; immune response; tumor microenvironment.