EZH2 INHIBITION ENHANCES T CELL IMMUNOTHERAPIES BY INDUCING LYMPHOMA IMMUNOGENICITY AND IMPROVING T CELL FUNCTION (CUT&RUN). EZH2 INHIBITION ENHANCES T CELL IMMUNOTHERAPIES BY INDUCING LYMPHOMA IMMUNOGENICITY AND IMPROVING T CELL FUNCTION (CUT&RUN)

While T cell immunotherapies have demonstrated effectiveness in a subset of patients with diffuse large B cell lymphoma (DLBCL) and follicular lymphoma (FL), they are currently administered without guidance regarding whether the underlying biology or immunology is conducive to a durable response. Moreover, mechanisms explaining CAR-T resistance in B cell lymphomas remain largely unknown, and suitable systems to study lymphomas are currently unavailable, making it infeasible. To address these unmet needs, we developed syngeneic animal models reflecting the genetics, epigenetics, and immunology of human FL and DLBCL. We show that treatment of these models with EZH2 inhibitors reprogrammed them to re-express T cell engagement genes and rendered them highly immunogenic. Notably, EZH2 inhibitors did not exhibit deleterious effects on T cells. Instead, they promoted a memory CAR CD8 phenotype and reduced exhaustion, resulting in a superior elimination of lymphoma B cells and decreased tumor burden. Intravital 2-photon imaging of transformed FL bearing mice showed that EZH2 inhibition increased the recruitment of CAR-T into the tumor microenvironment and enhanced the quality of interactions with lymphoma cells, leading to increased killing. Therefore, inhibition of EZH2 enhances CAR-T cell activity through direct effects on CAR-T cells, in addition to rendering lymphoma B cells immunogenic. This offers an innovative approach for enhancing the prognosis of patients with refractory B cell lymphomas, and is currently under evaluation in a clinical trial (NCT05934838) Overall design: CUT&RUN in tFL cell line model, PDX samples

尽管T细胞免疫疗法在弥漫性大B细胞淋巴瘤（diffuse large B cell lymphoma, DLBCL）与滤泡性淋巴瘤（follicular lymphoma, FL）的部分患者中已展现出临床疗效，但目前给药时并无相关指南可用于判断患者的内在生物学或免疫学特征是否有利于获得持久应答。此外，B细胞淋巴瘤中嵌合抗原受体T细胞（Chimeric Antigen Receptor T Cell, CAR-T）耐药的相关机制仍未完全阐明，且当前缺乏合适的淋巴瘤研究模型，导致相关研究难以推进。为解决这些未被满足的临床需求，我们构建了可模拟人类滤泡性淋巴瘤（follicular lymphoma, FL）与弥漫性大B细胞淋巴瘤（diffuse large B cell lymphoma, DLBCL）的遗传学、表观遗传学及免疫学特征的同基因动物模型。研究发现，利用EZH2（Enhancer of Zeste Homolog 2, EZH2）抑制剂处理此类模型后，可使其重激活T细胞结合相关基因的表达，进而显著增强其免疫原性。值得注意的是，EZH2抑制剂并未对T细胞产生有害影响；相反，其可促进记忆性CAR-CD8+ T细胞表型的形成，并减轻细胞耗竭，从而更高效地清除淋巴瘤B细胞，降低肿瘤负荷。对携带转化型滤泡性淋巴瘤（transformed follicular lymphoma, tFL）的小鼠进行活体双光子成像（intravital 2-photon imaging）结果显示，EZH2抑制可增加CAR-T细胞向肿瘤微环境的募集，并增强其与淋巴瘤细胞的相互作用质量，进而提升杀伤效果。综上，EZH2抑制除了可使淋巴瘤B细胞获得免疫原性之外，还可通过直接作用于CAR-T细胞来增强其抗肿瘤活性。这一策略为改善难治性B细胞淋巴瘤患者的预后提供了创新路径，目前已在一项临床试验（NCT05934838）中开展评估。整体实验设计：转化型滤泡性淋巴瘤细胞系模型的CUT&RUN（Cleavage Under Targets and Release Using Nuclease）实验、患者来源异种移植模型（Patient-Derived Xenograft, PDX）样本