Role of the METTL13 Lysine Methyltransferase in Signaling and Cancer

摘要 我们的首要目标是更好地了解细胞的翻译后修饰（PTM）的作用， 癌症中的蛋白质与潜在的假设，催化添加或去除的酶， 这些PTM是癌症的候选治疗靶点。虽然酶如蛋白激酶已经被广泛应用于 在癌症中进行了广泛的研究，最近出现了作为潜在癌症靶点的新类型的酶。在 特别地，超过100种赖氨酸甲基转移酶（KMT）被预测存在于人类蛋白质组中 并且许多与癌症病因学有关。然而，许多化合物的催化活性和底物特异性不高， 这些酶仍然是未知的。特别是，对于七个β-的大家族中的绝大多数都有作用 链KMT是未知。这里要检验的一个中心假设是， 孤儿KMT可能提供蛋白质赖氨酸甲基化信号传导和癌症生物学之间的新联系。 在这里，我们集中在候选人KMT胃L13（甲基转移酶样蛋白13）作为一个潜在的关键 肿瘤发生的调节因子。胃L13基因在许多癌症中扩增，并且胃L13 mRNA过度表达。 在不同的肿瘤类型中表达，包括几种肿瘤L13的表达与 患者生存率。然而，胃L13是一种孤儿酶，了解任何潜在的底物， 这种蛋白在细胞内和体内的总体作用模式是模糊的。根据初步观察，我们 假设胃L13上调蛋白质翻译以促进肿瘤发生。 在目的1中，我们表征了胃L13的生理催化活性和胃蛋白酶的分子功能。 胃L13在体外调节eEF1A活性和细胞蛋白质合成中的作用。我们亦会研究 胃L13和甲基化eEF1A相互作用伴侣以及这些途径如何交叉影响癌症 细胞表型目的2的目的是阐明胃L13在致癌KRAS驱动的肿瘤中的作用。 我们将检验这一假设，即胃L13通过其甲基化活性与KRAS信号传导合作， 使用胰腺导管的小鼠模型在体内促进癌细胞的无限扩增 腺癌和肺腺癌，其中RAS途径经常被激活。我们还将 使用患者来源的异种移植物（PDX）模型研究胃L13在人体组织中的致瘤作用。 我们将评估胃L13缺失对体内蛋白质翻译的影响。最后，我们将探索潜力 胃癌前病变中L13消融联合细胞存活和生长途径抑制剂的协同作用 胰腺癌和肺癌的临床模型。

ABSTRACT Our overarching goal is to better understand the role of post-translational modifications (PTMs) of cellular proteins in cancer with the underlying assumption that the enzymes that catalyze the addition or the removal of these PTMs are candidate therapeutic targets in cancer. While enzymes such as protein kinases have been extensively studied in cancer, new classes of enzymes have recently emerged as potential cancer targets. In particular, more than 100 lysine methyltransferases (KMTs) are predicted to be present in the human proteome and many are implicated in cancer etiology. However, the catalytic activity and substrate specificity for many of these enzymes remains unknown. In particular, functions for the vast majority of the large family of seven β- strand KMTs are not known. A central hypothesis to be tested here is that uncovering the activities of these orphan KMTs may provide new links between protein lysine methylation signaling and cancer biology. Here we focus on the candidate KMT METTL13 (Methyltransferase-like protein 13) as a potential critical regulator of tumorigenesis. The METTL13 gene is amplified in many cancers and METTL13 mRNA is over- expressed in diverse tumor types, including several were METTL13 expression negatively correlates with patient survival. However, METTL13 is an orphan enzyme and knowledge of any potential substrates and the overall mode of action of this protein in cells and in vivo is obscure. Based on preliminary observations, we hypothesize that METTL13 up-regulates protein translation to promote tumorigenesis. In Aim 1 we characterize the physiologic catalytic activity of METTL13 and the molecular functions of METTL13 in the regulation of eEF1A activity in vitro and in protein synthesis in cells. We will also investigate METTL13 and methylated eEF1A interacting partners and how these pathways intersect to influence cancer cell phenotypes. The goal of Aim 2 is to elucidate the role of METTL13 in tumors driven by oncogenic KRAS. We will test the hypothesis that METTL13, via its methylation activity, cooperates with KRAS signaling to promote the unlimited expansion of cancer cells in vivo using mouse models of pancreatic ductal adenocarcinoma and lung adenocarcinoma, in which the RAS pathway is frequently activated. We will also investigate the tumorigenic role of METTL13 in human tissue using patient-derived xenograft (PDX) models. We will assess the effects of METTL13 loss on protein translation in vivo. Finally, we will explore potential synergies of METTL13 ablation in combination with inhibitors of cell survival and growth pathways in pre- clinical models of pancreatic and lung cancers.