[F31] LARP1-Driven Control of Ribosomal Biogenesis Alters Translation in CAR T cells

Description

PROJECT SUMMARY. Chimeric Antigen Receptor T cell (CAR T) has been highly effective in treating hematological malignancies. Despite clinical benefits, CAR T cells efficacy is limited by poor persistence, which results in non-durable therapeutic responses in patients particularly with solid tumors due to the presence of an immunosuppressive and metabolically challenging tumor microenvironment. Our lab has identified the transcription factor FOXO1 enhances CAR T persistence and antitumor efficacy in vivo. FOXO1 overexpression also induces gene expression signatures of ribosomal biogenesis and global translation. Recent data from our lab has also shown that these gene signatures are enriched in pre-manufactured CAR T products that persist in patients, highlighting the link between persistence and control of translational machinery. However, the specific factors and signaling pathways that regulate ribosomal biology and mRNA translation in CAR T and how these pathways control CAR T antitumor activity remains unknown. To this end, I have uncovered a role for the ubiquitously expressed RNA- binding protein, LARP1, in dictating CAR T biology. LARP1 deletion in human CAR T increases CAR T expansion and rates of global translation upon antigen encounter. LARP1 deletion also enhances CAR T effector molecule production and control of tumor growth in vitro, indicating LARP1 as a promising target for strengthening CAR T therapies. My central hypothesis is that that LARP1 governs human CAR T differentiation and antitumor activity by altering the CAR T translatome. In Aim 1, I propose to determine the biochemical mechanism by which LARP1 controls ribosomal biogenesis. I hypothesize that constitutive LARP1-controlled expression of translational machinery drives both increased rates of ribosomal biogenesis and selective translation of effector molecules upon restimulation. I will evaluate this by overexpressing LARP1 in human CAR T and performing assays for global translation rates, ribosomal concentration, and bulk RNA-seq on actively translated mRNAs. In Aim 2, I will test the efficacy of LARP1 KO CAR T in vivo using liquid leukemia and solid osteosarcoma tumor models commonly utilized by my lab. I expect that LARP1 deletion will enhance both CAR T persistence and antitumor activity in both solid and liquid tumors. Given our established approaches for reprogramming CAR T cells, affiliations with two leading institutions for CAR T cell therapy, and carefully curated mentorship plan, I am well equipped and supported to complete the proposed work. Together, the findings of this work will describe a novel role for LARP1 as well as ribosomal biogenesis and global translation in CAR T persistence and antitumor activity and has potential to drive a new line of CAR T engineering focused on protein synthesis. Istituzione: UNIVERSITY OF PENNSYLVANIA PI: Oishi Bardhan Progetto: 1F31CA318731-01

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Source: reporter.nih.gov