Engineered Multicellular Tumor Models for Preclinical Therapeutic Testing

Abstract

Cancer is the leading cause of death, globally. The diversity of treatment options for patients with various cancers has come about due to shrewd biological investigation and pre-clinical models affording researchers with the ability to test therapeutics before entering clinical trials. However, while the use of mouse models and 2D in vitro systems has enabled the discovery of oncogenic pathways and testing of chemo-/immunotherapies leading to clinical trials and FDA-approval, the overall response rates for several cancer therapies remains low. The use of pre-clinical models which do not recapitulate key elements of the tumor microenvironment that could potentiate response to therapeutics is one reason for this disparity. Thus, the development of engineered in vitro models of the tumor which preserve native elements of the patient tumor or can be incorporated with other cell types to enable heterotypic cell-cell interactions has seen a surge in academic research. These efforts have resulted in the generation of new three-dimensional (3D) tumor models such as spheroids and organoids. However, while these 3D tumor models can preserve genetic and structural architecture of the tumors from which they derive, the deployment of such models for precision medicine and the tunability to incorporate other TME cell types is limited.Thus, the goal of my research is to develop novel preclinical in vitro models that can be used for both precision medicine and investigations of the effects of differential TME on drug efficacy and immune cell infiltration. To this end, I report three key studies leveraging organoids and microfluidics. Firstly, I contributed to development of a microfluidics-enabled droplet organoid platform which can generate thousands of monodisperse Matrigel-in-oil emulsions containing single tumor cells from a variety of cancerous tissue. I further demonstrated the use of these micro-organospheres for precision medicine and as a potential asset for adoptive T cell therapy testing. I then sought to leverage microphysiological modeling of the vasculature to probe the effect of cancer-associated fibroblasts on microvasculature formation and functionality. These results have implications for the tumor microenvironment, which presents aberrant tumor vasculature limiting drug penetration and immune infiltration. Finally, I leverage both organoids and microvascular networks to create vascularized lung tumor organoids. This novel 3D in vitro system enables both drug testing and T cell infiltration studies utilizing the microfluidic architecture to spatially confine cells of interest and observe potential effects on T cell infiltration. Overall, this dissertation offers new developments in preclinical 3D models of the tumor, ranging from high-throughput to high complexity. These findings have the potential to be deployed in precision medicine settings as well as for biological investigation of the various TME cell types and physicochemical factors influencing T cell infiltration.