Burkitt's lymphoma (BL) is a highly aggressive form of B-cell non-Hodgkin's lymphoma. The clinical outcome in children with BL has improved over the last years but the prognosis for adults is still poor, highlighting the need for novel treatment strategies. Here, we report that the combinational treatment with the Smac mimetic BV6 and TRAIL triggers necroptosis in BL when caspases are blocked by zVAD.fmk (TBZ treatment). The sensitivity of BL cells to TBZ correlates with MLKL expression. We demonstrate that necroptotic signaling critically depends on MLKL, since siRNA-induced knockdown and CRISPR/Cas9-mediated knockout of MLKL profoundly protect BL cells from TBZ-induced necroptosis. Conversely, MLKL overexpression in cell lines expressing low levels of MLKL leads to necroptosis induction, which can be rescued by pharmacological inhibitors, highlighting the important role of MLKL for necroptosis execution. Importantly, the methylation status analysis of the MLKL promoter reveals a correlation between methylation and MLKL expression. Thus, MLKL is epigenetically regulated in BL and might serve as a prognostic marker for treatment success of necroptosis-based therapies. These findings have crucial implications for the development of new treatment options for BL.

伯基特淋巴瘤 (BL) 是一种高度侵袭性的 B 细胞非霍奇金淋巴瘤。BL 儿童的临床结果在过去几年有所改善，但成人的预后仍然很差，这突出了对新治疗策略的需求。在这里，我们报告了当 caspase 被 zVAD.fmk（TBZ 治疗）阻断时，Smac 模拟 BV6 和 TRAIL 的联合治疗会触发 BL 中的坏死性凋亡。BL 细胞对 TBZ 的敏感性与 MLKL 表达相关。我们证明坏死性信号转导严重依赖于 MLKL，因为 siRNA 诱导的敲低和 CRISPR/Cas9 介导的 MLKL 敲除可极大地保护 BL 细胞免受 TBZ 诱导的坏死性凋亡。相反，在表达低水平 MLKL 的细胞系中 MLKL 过表达会导致坏死性凋亡诱导，这可以通过药理学抑制剂来挽救，强调 MLKL 在 necroptosis 执行中的重要作用。重要的是，MLKL 启动子的甲基化状态分析揭示了甲基化和 MLKL 表达之间的相关性。因此，MLKL 在 BL 中受到表观遗传调控，可能作为基于坏死性凋亡的疗法治疗成功的预后标志物。这些发现对开发新的 BL 治疗方案具有重要意义。