Engineering novel CAR-T cell therapy to overcome the cancer cell glycocalyx

Massachusetts General Hospital, Boston MA

Investigators

Abstract

Project Summary The cancer cell glycocalyx provides a major line of defense against detection and destruction by surveilling immune cells. By acting as a steric material barrier, the cancer cell glycocalyx can disrupt the close, intimate contact required for target engagement by effector immune cells. Cancer-associated cell-surface glycoproteins or glycans are highly upregulated in most breast cancer cells and glioblastoma. With the rapid advancement of immunotherapies and adoptive cell therapies for cancer, new strategies to disrupt or penetrate the glycocalyx barrier are needed for improved cancer immunotherapy, particularly for solid tumors. We recently found that cancer-associated mucins form a nanoscale shield, and even a 10-nanometer change in the glycocalyx thickness can significantly affect immune cell-mediated cytotoxicity. The long-term goal is to develop safe, effective CAR- T therapies for solid tumors. Thus, the overarching goal of this proposal is to develop new strategies to endow CAR-T cells that can bind to or penetrate the cancer-associated glycocalyx barrier in solid tumors. To attain the overall objective, we will pursue two specific aims: (1) Engineer CAR-T cells to strengthen the immune synapse by enhancing binding to the cancer cell glycocalyx and (2) Develop CAR-T cells that break through the cancer cell glycocalyx using cell-surface glycocalyx-editing (GE) enzymes and small-molecule inhibitors. In Aim 1, we will enhance CAR-T binding using two strategies: (i) Glyco-Bridge, an antigen receptor without an intracellular domain, and (ii) a leucine zipper-fused scFv approach (Zip-scFv). We hypothesize that Glyco-Bridge or Zip-scFv, will improve CAR-T activity by strengthening the immune synapse. In Aim 2, we will engineer CAR-T cells to express glycocalyx-editing enzymes on their membrane (GE-CART) to penetrate the barrier. We will also explore small-molecule inhibitors to reduce glycocalyx thickness and their synergy with CAR-T therapy. We hypothesize that GE enzymes or small-molecule inhibitors will reduce the glycocalyx, exposing tumor epitopes for more effective CAR-T recognition. These strategies aim to improve CAR-T therapy for solid tumors like breast cancer and glioblastoma by overcoming the glycocalyx barrier. To complete the aims, I have outlined a five-year career development plan that includes coursework, conferences, seminars, and structured mentoring in experimental design, glycomics, mouse modeling, CAR-T signaling, and clinical oncology. This plan is designed to acquire the necessary skills to perform my research and achieve my goal of becoming an independent investigator in both basic and translational research. This research is directly relevant to the mission of the NCI to conduct cancer research to advance scientific knowledge and help all people live longer healthier lives using immune cell therapies. Under the mentorship of Dr. Marcela Maus, a worldwide leader in cellular immunotherapy, I will conduct this research at Massachusetts General Hospital and benefit from the exceptional research and teaching environments provided by my scientific advisory committee, which includes Dana-Farber Cancer Institute, Beth Israel Deaconess Medical Center, Boston Children’s Hospital, and Massachusetts Institute of Technology.