Molecular Characterization of elF4B

弥漫性大B细胞淋巴瘤（DLBCL）代表非霍奇金淋巴瘤（NHL）的最常见亚型， 约占美国所有新确诊病例的40%。尽管相对成功， 前期R-CHOP治疗，复发/难治性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分子靶点的动力，以改善 成果。其中两个重连了脂肪酸合成酶（FATCH）和LKB 1（肝激酶）的代谢基因签名 B1）和蛋白质翻译机器组件正在成为治疗的假定候选者。 DLBCL的干预。在几个独立实验室的可靠数据的支持下， 分子、代谢特征，如脂肪酸代谢的扰动和LKB 1信号转导的缺失 与DLBCL存活率和潜在的淋巴瘤发生机制相关。然而，有限的成功， 由于药理学的局限性，靶向FXR和LKB 1的临床和临床前竞技场已经促使 研究人员确定下游效应物，提供可供选择的可采取行动的候选物， 抑制异质性DLCBL肿瘤生长。值得一提的是，来自我们实验室的令人兴奋的初步数据确定了eIF 4 B （真核起始因子4 B），一种关键的翻译机制组分，被增强的FGFAP激活， 活动人们普遍认为，不受调节的FXR活性与多药耐药性密切相关， 在R-CHOP耐药疾病患者中观察到显著特征。此外，我们还报告说， DLBCL改变的代谢组中的必需酶）直接调节PI 3 K/S6激酶介导的USP 11 （泛素特异性蛋白酶11）驱动的eIF 4 B活性，其增强DLBCL中的癌基因表达。 不幸的是，没有可用的小鼠模型来描述它们在B细胞中的生理作用， 发育和体内平衡。从我们早期发表的工作中提出的另一个关键问题是询问 与eIF 4 B泛素化机制相关的分子伴侣。初步调查结果显示， PARK 2作为潜在的E3连接酶，聚泛素化eIF 4 B。进一步扩大了我们对重新连接的 代谢对eIF 4 B驱动的翻译的影响，我们发现LKB 1磷酸化eIF 4 B，阻碍eIF 4 B- 敏感基因表达为了深入研究这些发现，我们将采取以下三项具体措施 目的：具体目的1：确定PARK 2在eIF 4 B和DLBCL的多聚泛素化中的分子作用 增殖，特异性目的2：确定LKB 1活性对eIF 4 B依赖性翻译的影响， 具体目标3：确定eIF 4 B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eIF 4 B在DLBCL中的功能重要性，我们将扩大我们的研究范围。 通过使用工程小鼠表征eIF 4 B在B细胞中的生理输入来理解机制 模型，并将其与其他临床相关的致癌驱动因子（Myc）交叉，以评估其贡献 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- 和转基因/过表达），以建立初步的体内证据，这将建立 eIF 4 B表达在B细胞淋巴瘤发生中的病理生理学影响。此外，使用分子，细胞， 和体内工具，我们的目标是验证我们提出的推定的E3连接酶，PARK 2，和能量激酶， LKB 1，影响eIF 4 B功能。有趣的是，我们注意到PARK 2和 DLBCL数据集中的LKB 1表达。我们预计，拟议的研究将阐明功能 以及在B-淋巴瘤的个体发育和病理生理学中eIF 4 B依赖和独立作用的分子事件。 细胞此外，与PARK 2和LKB 1相关的分子研究将显著增强我们对 这种重要的转录后/翻译机制调节eIF 4 B驱动的淋巴瘤发生。 最终，这些实验的成功完成将导致新的识别和验证。 DLBCL和相关淋巴恶性肿瘤中的可操作分子靶标。

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.