Biology subjects

Levine, L. S.

Publications and source records attributed to Levine, L. S..

3 recordsLinked to original sources

bioRxiv2023

Enhancing CAR-T Cell Metabolism to Overcome Hypoxic Conditions in the Brain Tumor Microenvironment

The efficacy of chimeric antigen receptor (CAR)-T therapy has been limited against brain tumors to date. CAR-T cells infiltrating syngeneic intracerebral SB28-EGFRvIII glioma revealed impaired mitochondrial ATP production and a markedly hypoxic status compared to ones migrating to subcutaneous tumors. Drug screenings to improve metabolic states of T cells under hypoxic conditions led us to evaluate the combination of AMPK activator Metformin and the mTOR inhibitor Rapamycin (Met+Rap). Met+Rap-pretreated mouse CAR-T cells showed activated PPAR-gamma coactivator 1 (PGC-1) through mTOR inhibition and AMPK activation, and a higher level of mitochondrial spare respiratory capacity than those pretreated with individual drugs or without pretreatment. Moreover, Met+Rap-pretreated CAR-T cells demonstrated persistent and effective anti-glioma cytotoxic activities in the hypoxic condition. Furthermore, a single intravenous infusion of Met+Rap-pretreated CAR-T cells significantly extended the survival of mice bearing intracerebral SB28-EGFRvIII gliomas. Mass cytometric analyses highlighted increased glioma-infiltrating CAR-T cells in the Met+Rap group with fewer Ly6c+ CD11b+ monocytic myeloid-derived suppressor cells in the tumors. Finally, human CAR-T cells pretreated with Met+Rap recapitulated the observations with murine CAR-T cells, demonstrating improved functions in vitro hypoxic conditions. These findings advocate for translational and clinical exploration of Met+Rap-pretreated CAR-T cells in human trials.

immunology↗

bioRxiv2022

T cell-instructed inflammation drives immune checkpoint inhibitor therapy resistance

Resistance to immune checkpoint inhibitors (ICIs) is common, even in tumors with T cell infiltration. We thus investigated consequences of ICI-induced T cell infiltration in the microenvironment of resistant tumors. T cells increased in ICI-resistant tumors following treatment as did neutrophils, in contrast to ICI-responsive tumors. Resistant tumors were distinguished by high expression of IL-1 Receptor 1 (IL1R1), enabling a synergistic response to IL-1 and TNF to induce G-CSF, CXCL1, and CXCL2 via NF-{kappa}B signaling, supporting neutrophils. Perturbation of this inflammatory resistance circuit sensitized tumors to ICIs. Paradoxically, T cells drove this resistance circuit via TNF both in vitro and in vivo. Evidence of this inflammatory resistance circuit and its impact also translated to human cancers. These data support a novel mechanism of ICI resistance, wherein treatment-induced T cell activity can drive resistance in tumors responsive to IL-1 and TNF, with important therapeutic implications. Statement of SignificanceAlthough T cell-infiltrated cancers are frequently resistant to immune checkpoint inhibitor therapies, mechanisms of resistance beyond T cell exhaustion remain unclear. Here, we reveal the functional significance of tumor- infiltrating T cells in resistant tumors, which surprisingly instruct immunosuppressive inflammation in mouse and human cancers responsive to IL-1 and TNF.

immunology↗

bioRxiv2020

Single-cell metabolic analysis by mass cytometry reveals distinct transitional states of CD8 T cell differentiation

Memory T cells conventionally rely on oxidative phosphorylation and short-lived effector T cells on glycolysis. Here, we investigate how T cells arrive at these states during an immune response. In order to understand the metabolic state of rare, early activated T cells, we adapted mass cytometry to quantify metabolic regulators at single-cell resolution in parallel with cell signaling, proliferation, and effector function. We interrogated CD8 T cell activation in vitro as well as the trajectory of CD8 T cells responding to Listeria monocytogenes infection, a well-characterized in vivo model for studies of T cell differentiation. This approach revealed a unique metabolic state in early activated T cells characterized by maximal expression of glycolytic and oxidative metabolic proteins. Peak utilization of both pathways was confirmed by extracellular flux analysis. Cells in this transient state were most abundant five days post-infection before rapidly downregulating metabolic protein expression. This approach should be useful for mechanistic investigations of metabolic regulation of immune responses.

immunology↗