Targeting CCR7-KMT2D enhances CAR-T cell efficacy by suppressing therapy-induced senescence in B-cell non-Hodgkin lymphoma

BACKGROUND: The efficacy of anti-CD19 Chimeric Antigen Receptor (CAR) T-cell therapy has been demonstrated in patients with relapsed or refractory B-cell non-Hodgkin lymphoma (B-NHL). However, therapy-induced senescence (TIS) has been identified as a novel resistance mechanism, potentially exacerbating immunosuppression and impairing CAR-T cell function. METHODS: Raji and SU-DHL-2 cells were treated with 40 nM doxorubicin (Dox) for 72 h to induce TIS, and CCR7 was inhibited with 10 µg/mL Cap-100. Cellular senescence was assessed by SA-β-Gal staining and flow cytometry; proliferation and apoptosis by CCK-8 and Annexin V/PI, respectively. CAR-T cytotoxicity was evaluated via flow cytometry. CCR7 expression on T cells from B-NHL patients and healthy controls was measured. Lentiviral transduction regulated CCR7 expression; protein expression and interactions were analyzed by Western blot and Co-IP. NF-κB and ARHGAP/RhoA pathways were inhibited using GS143 and Y27632, respectively. RESULTS: CCR7 overexpression enhanced SASP, while knockdown attenuated it. In the Dox-induced TIS model, KMT2D decreased, whereas H3K9me3, CCR7, and LGALS9 increased; CCR7 inhibition reversed these changes. Cap-100 improved CD19 CAR T killing by alleviating exhaustion in co-culture. Mechanistically, Cap-100 stabilized IκBα to inhibit NFκB, and inhibition of NFκB or ROCK reversed pro-senescence. Cap-100 reduced T cell proliferation but did not affect apoptosis or exhaustion. Clinically, CCR7 was lower on T cells from B NHL patients than healthy controls, and higher CCR7 correlated with better T cell quality. Transcriptomics showed Dox activated TIM3/Galectin 9 and PD- 1/PD-L1 pathways, while Dox + Cap-100 suppressed them. Co-IP confirmed interactions among CCR7, KMT2D, and LGALS9. Collectively, Dox induced TIS to upregulate CCR7, increasing SASP and LGALS9, which interacted with TIM-3, causing immune cell exhaustion and reducing killing efficiency; CCR7 blockade reversed this state and enhanced cytotoxicity. CONCLUSIONS: Our findings demonstrate that blockade of KMT2D-CCR7-mediated senescence enhances CD19 CAR-T cell anti-tumor activity in B-NHL.