Antoniolli Martina, Solovey Maria, Hildebrand Johannes Adrian, Freyholdt Tabea, Strobl Carolin Dorothea, Bararia Deepak, Keay William David, Adolph Louisa, Heide Michael, Passerini Verena, Winter Lis, Wange Lucas, Enard Wolfgang, Thieme Susanne, Blum Helmut, Rudelius Martina, Mergner Julia, Ludwig Christina, Bultmann Sebastian, Schmidt-Supprian Marc, Leonhardt Heinrich, Subklewe Marion, von Bergwelt-Baildon Michael, Colomé-Tatché Maria, Weigert Oliver
Laboratory for Experimental Leukemia and Lymphoma Research (ELLF), LMU University Hospital, Munich, Germany.
Department of Medicine III, LMU University Hospital, Munich, Germany.
Cell Death Differ. 2025 May;32(5):899-910. doi: 10.1038/s41418-025-01445-3. Epub 2025 Jan 23.
The cell death receptor FAS and its ligand (FASLG) play crucial roles in the selection of B cells during the germinal center (GC) reaction. Failure to eliminate potentially harmful B cells via FAS can lead to lymphoproliferation and the development of B cell malignancies. The classic form of follicular lymphoma (FL) is a prototypic GC-derived B cell malignancy, characterized by the t(14;18)(q32;q21)IGH::BCL2 translocation and overexpression of antiapoptotic BCL2. Additional alterations were shown to be clinically relevant, including mutations in ARID1A. ARID1A is part of the SWI/SNF nucleosome remodeling complex that regulates DNA accessibility ("openness"). However, the mechanism how ARID1A mutations contribute to FL pathogenesis remains unclear. We analyzed 151 FL biopsies of patients with advanced-stage disease at initial diagnosis and found that ARID1A mutations were recurrent and mainly disruptive, with an overall frequency of 18%. Additionally, we observed that ARID1A mutant FL showed significantly lower FAS protein expression in the FL tumor cell population. Functional experiments in BCL2-translocated lymphoma cells demonstrated that ARID1A is directly involved in the regulation of FAS, and ARID1A loss leads to decreased FAS protein and gene expression. However, ARID1A loss did not affect FAS promotor openness. Instead, we identified and experimentally validated a previously unknown co-transcriptional complex consisting of RUNX3 and ETS1 that regulates FAS expression, and ARID1A loss leads to reduced RUNX3 promotor openness and gene expression. The reduced FAS levels induced by ARID1A loss rendered lymphoma cells resistant to both soluble and T cell membrane-anchored FASLG-induced apoptosis, and significantly diminished CAR T cell killing in functional experiments. In summary, we have identified a functionally and clinically relevant mechanism how FL cells can escape FAS-dependent immune surveillance, which may also impact the efficacy of T cell-based therapies, including CAR T cells.
细胞死亡受体FAS及其配体（FASLG）在生发中心（GC）反应期间的B细胞选择中起关键作用。无法通过FAS消除潜在有害的B细胞会导致淋巴细胞增殖和B细胞恶性肿瘤的发展。经典型滤泡性淋巴瘤（FL）是一种典型的源自GC的B细胞恶性肿瘤，其特征为t(14;18)(q32;q21)IGH::BCL2易位和抗凋亡BCL2的过表达。其他改变也显示出与临床相关，包括ARID1A的突变。ARID1A是SWI/SNF核小体重塑复合体的一部分，该复合体调节DNA可及性（“开放性”）。然而，ARID1A突变如何促成FL发病机制仍不清楚。我们分析了151例初诊时处于晚期疾病患者的FL活检样本，发现ARID1A突变很常见且主要具有破坏性，总体频率为18%。此外，我们观察到ARID1A突变的FL在FL肿瘤细胞群体中FAS蛋白表达显著降低。在BCL2易位的淋巴瘤细胞中进行的功能实验表明，ARID1A直接参与FAS的调节，ARID1A缺失导致FAS蛋白和基因表达降低。然而，ARID1A缺失并不影响FAS启动子的开放性。相反，我们鉴定并通过实验验证了一种由RUNX3和ETS1组成的先前未知的共转录复合体，该复合体调节FAS表达，ARID1A缺失导致RUNX3启动子开放性和基因表达降低。ARID1A缺失诱导的FAS水平降低使淋巴瘤细胞对可溶性和T细胞膜锚定的FASLG诱导的凋亡均产生抗性，并在功能实验中显著降低了CAR T细胞的杀伤作用。总之，我们已经确定了FL细胞如何逃避FAS依赖性免疫监视的一种功能和临床相关机制，这也可能影响包括CAR T细胞在内的基于T细胞疗法的疗效。
