Anti-SLC7A11 monoclonal antibody Inhibits Tumor Progression through a Janus-faced Effect on CD4+ and CD8+ T Cells in Colorectal Cancer

While chimeric antigen receptor T cell therapy has demonstrated significant efficacy in treating hematological malignancies, its application in solid tumors remains challenging. A primary factor contributing to the limited efficacy of CAR-T cells in solid tumors is the dysfunction of CD8+ T cells, which is often a result of exhaustion. However, emerging evidence suggests that modulating cellular metabolism holds promise for enhancing the functionality of CD8+ T cells. An experimental model of CD8⁺ T cell exhaustion was established, followed by RNA sequencing to profile the expression of SLC family genes, which are implicated in metabolic regulation and CD8⁺ T cell differentiation. Monoclonal antibodies were generated using hybridoma technology and subsequently humanized. The effects of antibody treatment on CD8⁺ T cell differentiation and exhaustion were assessed via flow cytometry and western blotting. To evaluate therapeutic efficacy, cell-derived xenograft models of colorectal and breast cancer were established, and the combined effect of the antibody with CAR-T cells was examined. Furthermore, CRISPR/Cas9-mediated gene-edited mouse models were generated, and single-cell sequencing was performed to monitor changes in tumor burden and the differentiation status of tumor-infiltrating CD8⁺ T cells. RNA sequencing analysis revealed that SLC7A11 was significantly upregulated in exhausted CD8⁺ T cells. A monoclonal antibody specifically targeting SLC7A11 was generated, and its binding affinity was rigorously validated. Functional studies demonstrated that inhibition of SLC7A11 promoted the expansion of CD8⁺ T stem cell memory cells and attenuated the exhausted phenotype. In vivo studies further showed that anti-SLC7A11 treatment enhanced the antitumor efficacy of CAR-T cells. The effects were mediated through the suppression of cystine uptake via SLC7A11 inhibition, thereby modulating the GCN2-eIF2α-SLC1A5 signaling axis. Restricting cystine uptake enhances the efficacy of CD8+ CAR-T cells and alleviates tumor burden.