Abstract C022: T cell movement through complex obstacles presented by the microenvironment of pancreatic tumor spheroids

Abstract

Abstract Immunotherapy has emerged as a promising approach for treating pancreatic cancer, however its efficacy against solid tumors has been largely limited. In order to be effective, cell-based immunotherapies are required to be in close proximity with the target cancerous cells. However, owing to its dense desmoplastic stroma, many regions of a pancreatic tumor, have areas within the tumor volumes that exclude anti-tumor immune cells. Therefore, we need to define mechanisms used by therapeutic T cells to navigate effectively in some tumor regions and the barriers that limit their infiltration and distribution in other regions of the tumor microenvironment (TME). In this work, we have advanced our knowledge of T cell migration and infiltration through complex TMEs by analyzing T cell dynamics in 3D engineered in vitro environments that can replicate key TME features of pancreatic ductal adenocarcinoma (PDA). Using our state-of the-art imaging techniques with multiphoton excitation (MPE) and second harmonic generation (SHG), we have monitored the migration of engineered human mesothelin reactive CAR-T cells through fibrous microenvironments and their interactions with pancreatic tumor spheroids. Quantitative analysis of interactions between CAR-T cells and carcinoma cells, in terms of velocity, directionality and mean square displacement (MSD) were performed, with the aim of utilizing these phenotypes as “design criteria” for the development of more effective engineered T cell therapies. The therapeutic efficacy of engineered T cells was also evaluated in standard 2D killing assays and then new 3D assays of increased complexity, both of which revealed mesothelin specific cancer cell death. Overall, we are starting to define the physical and molecular mechanisms that result in resistance to immunotherapy against pancreatic cancer, and we anticipate that our work will be applicable to other solid tumors with similar challenges and address key unanswered question in cancer biology. Citation Format: Shambojit Roy, Zhongming Chen, Guhan Qian, Paolo P. Provenzano. T cell movement through complex obstacles presented by the microenvironment of pancreatic tumor spheroids [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr C022.