BCMA CAR-T Cell(Xuzhou Medical University)

Glutamine dependence of cancer cells reduces local glutamine availability, which hinders antitumor T-cell functionality and facilitates immune evasion. We thus speculated that glutamine deprivation might be limiting efficacy of chimeric antigen receptor (CAR) T-cell therapies in patients with cancer. We have seen that antigen-specific T cells are unable to proliferate or produce interferon gamma (IFN-γ) in response to antigen stimulation when glutamine concentration is limited. Using multiple myeloma (MM) as a glutamine-dependent disease model, we found that murine CAR T cells selectively targeting B-cell maturation antigen (Bcma) in MM cells were sensitive to glutamine deprivation. However, CAR T cells engineered to increase glutamine uptake by expression of the glutamine transporter Asct2 exhibited enhanced proliferation and responsiveness to antigen stimulation, increased production of IFN-γ, and heightened cytotoxic activity, even under conditions of low glutamine concentration. Mechanistically, Asct2 overexpression reprogrammed the metabolic fitness of CAR T cells by upregulating the mechanistic target of rapamycin complex 1 gene signature, modifying the solute carrier transporter repertoire, and improving both basal oxygen consumption rate and glycolytic function, thereby enhancing CAR T-cell persistence in vivo. Accordingly, expression of Asct2 increased the efficacy of Bcma-CAR T cells in syngeneic and genetically engineered mouse models of MM, which prolonged mouse survival. In patients, higher-level expression of ASCT2 by MM cells predicted poor outcome to combined immunotherapy and BCMA-CAR T-cell therapy. Our results indicate that reprogramming glutamine metabolism may enhance antitumor CAR T-cell functionality in MM. This approach may also be effective for other cancers that depend on glutamine as a key energy source and metabolic hallmark.

While most patients initially respond to CAR-T cell treatment, responses often are not durable and subsequent lines of immunotherapy show diminishing success. In this study, we investigated the co-evolutionary dynamics between CAR-T cells and the immune microenvironment in myeloma patients undergoing anti-BCMA CAR-T cell therapy at single-cell resolution. Our findings highlight the transformative impact of CAR-T cell treatment on the endogenous T cell landscape. We identify a novel transitional CD8 + T cell population that is predictive of poor treatment outcomes. The emergence of this population coincides with the depletion of the endogenous T cell repertoire and compositional evolution of functional T cell subsets. These changes in the endogenous T cell compartment induced by CAR-T cell therapy may contribute to inadequate immune capacity and tumor control. Our findings highlight the potential of targeting TIM3/GAL9 interactions to mitigate T cell exhaustion, apoptosis and lack of persistence, offering promising avenues for optimizing T cell-based cancer immunotherapies. We provide a framework for assessing and manipulating the ‘mileage’ of the immune system as predictive marker and therapeutic opportunity to prevent repeated immunotherapies from becoming increasingly less successful, even when targeting distinct antigens.