Abstract LB014: Carbon monoxide induced PERK regulated autophagy reprograms anti-tumor T cells with robust immunometabolic phenotype

Abstract

Abstract Mitochondria and Endoplasmic reticulum (ER) share structural and functional networks to maintain cellular homeostasis and activate well-orchestrated signaling processes to shape cells' fate and function. While persistent ER stress (ERS) response leads to mitochondrial collapse, moderate ERS condition drives mitochondrial biogenesis and function. So far, various strategies have been tested to enhance the mitochondrial function in T cells to improve their anti-tumor potential. However, strategies targeting ER-Mitochondria crosstalk (by employing moderate ERS condition) to boost the anti-tumor T cell function have not been exploited yet. Thus, in the present study, we used carbon monoxide (CO), a short-lived gaseous molecule, to test if engaging moderate ERS conditions can improve T cells mitochondrial biogenesis, function, and anti-tumor therapeutic efficacy. Using melanoma antigen gp100 reactive T cells, we identify that CO induced transient activation of ERS sensor ‘protein kinase R-like endoplasmic reticulum kinase (PERK)’ dramatically increase anti-tumor T cell function. Furthermore, mechanistically we found that CO-induced PERK activation temporarily halts protein translation and induces protective autophagy (that includes mitophagy). To get further insight into how CO treatment kinetically regulates autophagic activity in T cells, we used LC3-GFP to differentiate between the cells that prepare themselves to undergo active autophagy (LC3-GFPpos) and those that fail to enter into the process (LC3-GFPneg). Using Ag-specific LC3-GFP expressing T cells, we demonstrate that LC3-GFPpos T cells show robust anti-tumor potential. Moreover, LC3-GFPneg shows a T regulatory-like phenotype, harbors dysfunctional mitochondria, and accumulates abnormal metabolite content. These anomalous ratios of metabolites render the cells with a hypermethylated state and distinct epigenetic profile limiting their anti-tumor activity. Overall, this preclinical data highlights that ERS-mediated activation of autophagy pathways modifies the mitochondrial function and epigenetically reprogram the T cells towards a superior anti-tumor phenotype and can be therapeutically translated to achieve robust tumor control in adoptive transfer therapies. Citation Format: Paramita Chakraborty, Rasesh Y. Parikh, Seungho Choi, Meenal Mehrotra, Eduardo N. Maldonado, Hongjun Wang, J. Alan Diehl, Vamsi K. Gangaraju, Shikhar Mehrotra. Carbon monoxide induced PERK regulated autophagy reprograms anti-tumor T cells with robust immunometabolic phenotype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB014.