Targeting the Unique Paracaspase MALT1 to Overcome Ibrutinib Resistance in Relapsed/Refractory MCL Patients

摘要 套细胞淋巴瘤(MCL)是一种尚未治愈的侵袭性B细胞恶性肿瘤。两者都是单一疗法 Bruton‘s酪氨酸激酶抑制剂ibrutinib和BH3模拟BCL2抑制剂ventoclax联合使用 已被证明是治疗MCL的有效选择。然而，接受治疗的患者中只有21% 单一疗法伊布鲁替尼或万乃馨和71%接受联合治疗的患者达到了 完整的回应。此外，单耐药和双耐药经常出现。因此，当务之急是 未得到满足的需要，以克服对这些药物的耐药性，并研究替代治疗方案。构造性核因子- κB的激活是MCL的一个标志。事实上，110例MCL患者样本的下一代测序分析 研究发现，NF-κB信号通路中的基因突变率最高(29%)，表明 核因子-κB信号转导在多囊卵巢癌伊布鲁替尼耐药中的作用通过整个转录测序，我们 显示黏膜相关淋巴组织转化蛋白(MALT1)过表达 对伊布鲁替尼耐药和伊布鲁替尼-维奈替克双重耐药的MCL细胞过度活跃。Malt1是独一无二的 在人类基因组中，它在NF-κB信号转导中起关键作用，提示MALT1. 可能是克服伊布鲁替尼耐药和伊布鲁替尼-维奈替克双重耐药的潜在治疗靶点 没有明显的偏离目标的副作用。事实上，MI-2，一种MALT1抑制剂，已经被证明选择性地靶向 活化B细胞样弥漫性大B细胞淋巴瘤和慢性淋巴细胞白血病中MALT1的表达我们的预赛 数据显示，MI-2对耐药的MCL细胞和耐药的MCL细胞有很强的杀伤作用。 解决MALT1导致治疗耐药的潜在机制以及靶向 MALT1可以克服伊布鲁替尼耐药和伊布鲁替尼-维奈替克双重耐药，我们的目标是：1)确定 MI-2单独或联合用药对MCL细胞株、原发MCL患者的疗效 2)MALT1介导的MCL疾病发生机制的研究 MALT1临床突变株体外导入MCL细胞的进展及伊布鲁替尼-维奈替克耐药性； 3)确定单独靶向MALT1或与其他靶点(S)联合治疗伊布鲁替尼-维奈替克的疗效 体内耐药采用MCL PDX小鼠模型。成功完成拟议的研究将提供 强有力的证据表明MALT1在MCL恶性肿瘤和治疗耐药中的作用以及如何 靶向独特的副天冬氨酸酶MALT1可能克服伊布鲁替尼耐药和伊布鲁替尼-维尼托克拉克斯双重耐药 耐药，最终导致临床策略治疗伊布鲁替尼和/或万乃馨-难治性/复发性MCL 病人。

SUMMARY Mantle cell lymphoma (MCL) is an aggressive B-cell malignancy that is not yet curable. Both as monotherapies and in combination, the Bruton's tyrosine kinase inhibitor ibrutinib and the BH3 mimetic BCL2 inhibitor venetoclax have proven to be effective treatment options for MCL. However, only 21% of patients who received monotherapies ibrutinib or venetoclax and 71% of patients who received the combined therapy achieved a complete response. Furthermore, mono- and dual resistance frequently develops. Therefore, there is an urgent unmet need to overcome resistance to these agents and to study alternative treatment options. Constitutive NF- κB activation is a hallmark of MCL. Indeed, next generation sequencing analysis of 110 MCL patient samples revealed that genes in the NF-κB signaling pathway had the highest mutation rate (29%), indicating the significant contribution of NF-κB signaling to ibrutinib resistance in MCL. Through whole transcriptomic sequencing, we showed that mucosa-associated lymphoid tissue transformation protein (MALT1) is overexpressed and hyperactive in ibrutinib-resistant and ibrutinib-venetoclax dual-resistant MCL cells. MALT1 is a unique paracaspase within the human genome, and it plays a crucial role in NF-κB signaling, suggesting that MALT1 may be a potential therapeutic target to overcome ibrutinib resistance and ibrutinib-venetoclax dual-resistance without significant off-target side effects. Indeed, MI-2, a MALT1 inhibitor, has been shown to selectively target MALT1 in activated B-cell-like diffuse large B-cell lymphoma and chronic lymphocytic leukemia. Our preliminary data show that MI-2 is highly potent in killing ibrutinib-resistant and ibrutinib-venetoclax dual-resistant MCL cells. To address the underlying mechanisms by which MALT1 contributes to therapeutic resistance and how targeting MALT1 can overcome ibrutinib resistance and ibrutinib-venetoclax dual resistance, we aim to 1) determine the efficacy of MI-2 as a single agent or in combination with other agents in MCL cell lines, primary MCL patient samples, and PDX models in vitro; 2) characterize MALT1-mediated mechanisms underlying MCL disease progression and ibrutinib-venetoclax resistance by introducing MALT1 clinical mutants into MCL cells in vitro; and 3) determine the efficacy of targeting MALT1 alone or with other target(s) to overcome ibrutinib-venetoclax resistance in vivo using MCL PDX mouse models. Successful completion of the proposed study will provide strong evidence demonstrating the role of MALT1 in MCL malignancy and therapeutic resistance and how targeting the unique paracaspase MALT1 may overcome ibrutinib resistance and ibrutinib-venetoclax dual resistance, ultimately leading to clinical strategies to treat ibrutinib and/or venetoclax-refractory/relapsed MCL patients.