Follicular Lymphoma-associated BTK Mutations are Inactivating Resulting in Augmented AKT Activation.
Follicular Lymphoma-associated BTK Mutations are Inactivating Resulting in Augmented AKT Activation.
复制标题
滤泡性淋巴瘤相关BTK突变失活导致AKT活化增强
DOI：
10.1158/1078-0432.ccr-20-3741
复制
发表时间：
2021-04-15
期刊：
影响因子：
--
通讯作者：
Malek SN
中科院分区：
文献类型：
--
作者：
Hu N;Wang F;Sun T;Xu Z;Zhang J;Bernard D;Xu S;Wang S;Kaminski M;Devata S;Phillips T;Malek SN
根据最近在滤泡性淋巴瘤(FL)中发现的Bruton酪氨酸激酶(BTK)突变，我们研究了它们的功能特性。我们在139例FL和11例转化FL患者中发现了7%的新的体细胞BTK突变，这些患者都没有接受过B细胞受体(BCR)靶向药物的治疗。我们将WT和突变型BTK基因重组到各种基因工程淋巴瘤细胞系中。我们测量了BCR在工程细胞系和原代人类FL B细胞中诱导的信号转导事件。我们发现，所有的BTK突变体都破坏了BTK蛋白的稳定，一些突变产生了BTK激酶死亡的突变体。PLCγ2是Btk的底物，但btk突变体不改变PLCγ2的磷酸化。相反，我们发现BTK突变体在抗免疫球蛋白(IG)处理的重组淋巴瘤细胞系中诱导了夸大的AKT磷酸化表型。ShRNA介导的BTK在原代人类非恶性淋巴结来源的B细胞中的表达下调导致了抗IG诱导的AKT的强烈激活，同样，使用基于伊布鲁替尼的蛋白水解靶向嵌合体(PROTAC)的细胞系中BTK蛋白的降解也是如此。最后，通过对携带WT或突变型BTK的原代人FL B细胞的分析，我们检测到所有FL B细胞，包括所有BTK突变型FL，表面IG交联后AKT磷酸化水平升高。用PI3Kδ抑制剂预处理可使bcr交联后的蛋白酪氨酸氨基转移酶磷酸化增强。总之，我们的数据揭示了FL相关BTK突变的新的意想不到的特性，对FL的靶向治疗开发具有直接的意义。
Based on the recent discovery of mutations in Bruton’s tyrosine kinase (BTK) in Follicular Lymphoma (FL), we studied their functional properties. We identified novel somatic BTK mutations in 7% of a combined total of 139 FL and 11 transformed FL cases, none of which had received prior treatment with B cell receptor (BCR) targeted drugs. We reconstituted WT and mutant BTK into various engineered lymphoma cell lines. We measured BCR-induced signal transduction events in engineered cell lines and primary human FL B cells. We uncovered that all BTK mutants destabilized the BTK protein and some created BTK kinase-dead mutants. The PLCγ2 is a substrate of BTK but the BTK mutants did not alter PLCγ2 phosphorylation. Instead, we discovered that BTK mutants induced an exaggerated AKT phosphorylation phenotype in anti-immunoglobulin (IG) treated recombinant lymphoma cell lines. The shRNA-mediated knock-down of BTK expression in primary human non-malignant lymph node-derived B cells resulted in strong anti-IG-induced AKT activation, as did the degradation of BTK protein in cells lines using ibrutinib-based proteolysis targeting chimera (PROTAC). Finally, through analyses of primary human FL B cells carrying WT or mutant BTK, we detected elevated AKT phosphorylation following surface IG crosslinking in all FL B cells, including all BTK mutant FL. The augmented AKT phosphorylation following BCR crosslinking could be abrogated by pre-treatment with a PI3Kδ inhibitor. Altogether, our data uncover novel unexpected properties of FL-associated BTK mutations with direct implications for targeted therapy development in FL.