Molecular Characterization of elF4B

弥漫性大B细胞淋巴瘤(DLBCL)是最常见的非霍奇金淋巴瘤(NHL)亚型， 约占美国所有新诊断病例的40%。尽管相对成功的是 前期R-CHOP治疗、复发/难治病例的频繁发生以及治疗的局限性 患有共病的患者提供了发现新的可操作的分子靶点以改善病情的动力 结果。其中两个重新连接的代谢基因信号是脂肪酸合成酶(FASN)和LKB1(肝激酶 1)和蛋白质翻译机械组件正在成为治疗的假定候选者 对DLBCL的干预。在来自几个独立实验室的可靠数据的支持下，识别唯一的 分子代谢特征，如脂肪酸代谢紊乱和LKB1信号缺失 与DLBCL的生存和潜在的淋巴瘤发生机制有关(S)。然而，在以下方面的成功有限 由于药物的局限性，以FASN和LKB1为靶点的临床和临床前领域已被激发 调查人员识别下游效应器，为可操作的替代候选者提供适用性 抑制异种DLCBL肿瘤生长。需要指出的是，来自我们实验室的令人兴奋的初步数据确定了eIF4B (真核细胞起始因子4B)，一个关键的翻译机械组件，被增强的FASN激活 活动。人们普遍认为，FASN活性不受调控与多药耐药密切相关， 在R-CHOP抵抗疾病患者中观察到显著的特征。此外，我们还报告了FASN(An DLBCL改变代谢产物中的必需酶直接调节PI3K/S6Kinase介导的USP11 (泛素特异性蛋白酶11)驱动eIF4B活性，从而增强DLBCL中癌基因的表达。 不幸的是，目前还没有可用的小鼠模型来描述它们在B细胞中的生理作用 发展和动态平衡。从我们先前发表的作品中提出的另一个关键问题是询问 与eIF4B泛素化机制相关的分子伙伴。初步调查结果显示 PARK2作为潜在的E3连接酶，泛素化eIF4B。进一步扩大了我们对重新布线的观察 代谢对eIF4B驱动的翻译的影响，我们发现LKB1使eIF4B磷酸化，阻碍eIF4B- 敏感基因表达。为了深入解决这些发现，我们将进行以下三项具体工作 目的：特定目标1：确定PARK2在eIF4B和DLBCL多泛素化中的分子作用 增殖，特定目标2：确定LKB1活性对eIF4B依赖的翻译和 特异性目标3：确定eIF4B在B细胞中的分子依赖性。虽然我们已经获得了 令人信服的基于细胞的数据证明了eIF4B在DLBCL中的功能重要性，我们将扩展我们的 利用工程化小鼠研究eIF4B在B细胞中的生理输入机制 模型，并将它们与其他临床相关的致癌驱动因素(Myc)进行交叉，以评估它们的贡献 与淋巴瘤的发展和进展有关。我们已经合成了互补的小鼠模型(敲击- Out和转基因/过表达)来建立体内初步证据，这将建立 EIF4B表达在B细胞淋巴瘤发生中的病理生理影响此外，使用分子、细胞、 在活体工具中，我们的目标是验证我们提出的推定的E3连接酶，PARK2，和能量学激酶， LKB1，影响eIF4B功能。有趣的是，我们注意到PARK2和PARK2之间存在显著正相关 DLBCL数据集中的LKB1表达式。我们预计，拟议的研究将阐明功能 以及eIF4B依赖和独立的分子事件在B细胞的个体发育和病理生理中的作用 细胞。此外，与PARK2和LKB1相关的分子研究将显著增强我们对 这一关键的转录后/翻译机制(S)调控eIF4B驱动的淋巴肿大。 最终，这些实验的成功完成将导致对小说的识别和验证 DLBCL及相关淋巴系统恶性肿瘤的可操作分子靶点S。

Diffuse large B-cell lymphoma (DLBCL) represents the most common subtype of non-Hodgkin lymphoma (NHL), accounting for about 40% of all newly diagnosed cases in the United States. Despite the relative success of upfront R-CHOP therapy, the frequent occurrence of relapsed/refractory cases and the limitations to treating patients with co-morbidities has provided the impetus to discover novel actionable molecular targets to improve outcomes. Two of these rewired metabolic gene signatures of fatty acid synthase (FASN) & LKB1 (Liver Kinase B1) and the protein translational machinery components are emerging as putative candidates for therapeutic intervention in DLBCL. Supported by robust data from several independent laboratories, identification of unique molecular, metabolic signatures such as perturbation in fatty acid metabolism and depletion of LKB1 signaling are associated with DLBCL survival and underlying lymphomagenic mechanism(s). However, limited success in the clinical and pre-clinical arena targeting FASN and LKB1 due to pharmacological limitations has motivated investigators to identify downstream effectors, providing alternative actionable candidates with applicability in suppressing heterogenous DLCBL tumor growth. To point, exciting preliminary data from our lab identified eIF4B (Eukaryotic initiation factor 4B), a critical translational machinery component, is activated by enhanced FASN activity. It is broadly accepted that unregulated FASN activity is strongly correlated with multi-drug resistance, a prominent feature observed in patients with R-CHOP resistant disease. Further, we reported that FASN (an essential enzyme in the altered metabolome of DLBCL) directly regulates PI3K/S6Kinase mediated USP11 (Ubiquitin Specific Protease 11) driven eIF4B activity, which enhances oncogene expression in DLBCL. Unfortunately, there are no available murine models to delineate their physiological roles in B-cell development and homeostasis. Another critical question raised from our earlier published work was interrogating the molecular partners associated with the eIF4B ubiquitination machinery. Preliminary findings revealed PARK2 as a potential E3 Ligase, polyubiquitinating eIF4B. Further expanding our observation of the rewired metabolic impact on eIF4B driven translation, we found that LKB1 phosphorylates eIF4B, hindering eIF4B- sensitive gene expression. To address these findings in-depth, we will pursue the following three specific aims: Specific Aim 1: Define the molecular role of PARK2 in polyubiquitination of eIF4B and DLBCL proliferation, Specific Aim 2: Determine the impact of LKB1 activity on eIF4B-dependent translation and Specific Aim 3: Determine the molecular dependence of eIF4B in B-cells. While we have acquired compelling cell-based data demonstrating the functional importance of eIF4B in DLBCL, we will expand our mechanistic understanding by characterizing the physiological inputs of eIF4B in B-cells using engineered mouse models as well as crossing them with other clinically relevant oncogenic drivers (Myc) to assess their contribution to the development and progression of lymphomas. We have synthesized complementary mouse models (knock- out and transgenic/overexpression) to establish prima facia in vivo evidence, which will establish the pathophysiological impact of eIF4B expression in B-cell lymphomagenesis. Further, using molecular, cellular, and in vivo tools, we aim to validate how our proposed putative E3 ligase, PARK2, and the energetics kinase, LKB1, impact eIF4B functionality. Interestingly, we noted a significant positive correlation between PARK2 and LKB1 expression in the DLBCL dataset. We anticipate that the proposed studies will shed light on the functional and molecular events of eIF4B-dependent and independent roles in the ontogeny and pathophysiology of B- cells. In addition, molecular studies related to PARK2 and LKB1 will significantly enhance our understanding of this crucial post-transcriptional/translational mechanism(s) regulating eIF4B-driven lymphomagenesis. Ultimately, the successful completion of these experiments will lead to the identification and validation of novel actionable molecular target(s) in DLBCL and related lymphoid malignancies.