Role of the METTL13 Lysine Methyltransferase in Signaling and Cancer

摘要 我们的首要目标是更好地理解细胞翻译后修饰(PTM)的作用 癌症中的蛋白质，其基本假设是催化添加或移除 这些PTM是癌症的候选治疗靶点。而像蛋白激酶这样的酶已经 在癌症中被广泛研究的新类别的酶最近已成为潜在的癌症靶点。在……里面 特别是，人类蛋白质组中预计存在100多个赖氨酸甲基转移酶(Kmt)。 其中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专一性 这些酶仍然是未知的。特别是，七人大家庭中的绝大多数β的功能- 链KMT尚不为人所知。这里要检验的一个中心假设是，揭示这些 孤儿KMT可能在蛋白质赖氨酸甲基化信号和癌症生物学之间提供新的联系。 在这里，我们关注候选的KMT METTL13(甲基转移酶样蛋白13)作为潜在的关键 肿瘤发生的调节因子。METTL13基因在许多癌症中被扩增，并且METTL13基因的mRNA过度表达。 在不同肿瘤类型中的表达，包括几种均与METTL13的表达呈负相关 病人存活率。然而，METTL13是一种孤立的酶，知道任何潜在的底物和 这种蛋白质在细胞和体内的整体作用方式尚不清楚。根据初步观察，我们 假设METTL13上调蛋白质翻译以促进肿瘤发生。 在目标1中，我们表征了METTL13的生理催化活性以及它的分子功能。 METTL13在体外对eEF1A活性和细胞蛋白质合成的调节作用。我们还将调查 METTL13和甲基化的eEF1A相互作用伙伴以及这些通路如何相交影响癌症 细胞表型。目标2的目的是阐明METTL13在致癌KRAS驱动的肿瘤中的作用。 我们将检验这一假设，即METTL13通过其甲基化活性，与KRAS信号合作，以 用小鼠胰腺导管模型促进体内癌细胞的无限扩增 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(PDX)模型研究METTL13在人体组织中的致瘤作用。 我们将评估METTL13缺失对体内蛋白质翻译的影响。最后，我们将发掘潜力 METTL13消融与细胞存活和生长途径抑制剂联合应用的协同作用 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.