Development of 3D breast cancer models with human T cells expressing engineered MAIT cell receptors

Abstract

Immunotherapy has revolutionized cancer treatment with the advent of advanced cell engineering techniques aimed at targeted therapy with reduced systemic toxicity. However, understanding the underlying immune-cancer interactions require development of advanced three-dimensional (3D) models of human tissues. In this study, we developed proof-of-concept 3D tumor models with increasing complexity to study the cytotoxic responses of CD8+ T cells, genetically engineered to express mucosal-associated invariant T (MAIT) cell receptors, towards MDA-MB-231 breast cancer cells. Homotypic MDA-MB-231 and heterotypic MDA-MB-231/human dermal fibroblast (HDF) tumor spheroids were primed with precursor MAIT cell ligand 5-amino-6-D-ribitylaminouracil (5-ARU). Engineered T cells effectively eliminated tumors after a 3-day culture period, demonstrating that the engineered TCR recognized MR1 expressing tumor cells in the presence of 5-ARU. Tumor cell killing efficiency of engineered T cells were also assessed by encapsulating these cells in fibrin, mimicking a tumor extracellular matrix microenvironment. Expression of proinflammatory cytokines such as IFN, IL-13, CCL-3 indicated immune cell activation in all tumor models, post immunotherapy. Further, in corroborating the cytotoxic activity, we found that granzymes A and B were also upregulated, in homotypic as well as heterotypic tumors. Finally, a 3D bioprinted tumor model was employed to study the effect of localization of T cells with respect to tumors. T cells bioprinted proximal to the tumor had reduced invasion index and increased cytokine secretion, which indicated a paracrine mode of immune-cancer interaction. Development of 3D tumor-T cell platforms may enable studying the complex immune-cancer interactions and engineering MAIT cells for cell-based cancer immunotherapies.

Mucosal-associated invariant T cells in cancer: dual roles, complex interactions and therapeutic potential

“…Discrepancies in MR1 expression across various tumor cell lines and the resulting differences in MAIT cell response underscore the complexity of the immune system’s interaction with cancer. Utilization of 3D bioprinted tumor models to study the effect of localization and activation of MAIT cells within the 3D tumor tissue model could help elucidate and these complex interactions ( 99 ).…”

“…Furthermore, several studies demonstrated the potential for MAIT cells in solid tumor-targeting immunotherapies due to their natural ability to infiltrate tissue sites of chronic inflammation and their abundance in the tumor microenvironment ( 99 , 101 , 109 , 110 ). In this tumor environment, MAIT cells can also act as innate T cells with the potential to bridge innate and adaptive immune immunity, and can rapidly exert their effector functions upon activation without the requirement for clonal expansion, similar to innate immune ( 111 ) ( 112 ).…”

Opportunities and challenges to engineer 3D models of tumor-adaptive immune interactions

“…RNAseq analysis supported their hypothesis that the bioprinted model better mimicked the physiological environment (Figure 2C). To create a tumorimmune interaction model, Dey et al printed a ring of T cells into a collagen bath and deposited a single MDA-MB-231/human dermal fibroblast spheroid in the center (Figure 2D) (73). In each of the print designs, cancer cells migrated from the central spheroid and invaded into the collagen matrix.…”