Mechanism of action of the SETD5 protein methyltransferase in pancreatic ductal adenocarcinoma.

胰腺癌是一种毁灭性的疾病，尽管在过去30年中进行了深入的研究，但胰腺癌的5年生存率仍然很低。这主要是由于诊断较晚和治疗方案无效。虽然针对Ras信号传导途径激酶的靶向疗法在体外和体内显示出有希望的效果，但由于高毒性、低功效和治疗抗性的发展，它们在临床试验中仍然基本上无效。赖氨酸甲基转移酶（KMTs），进行翻译后修饰，已成为潜在的关键调控癌症途径。与在肿瘤发生中具有明确作用的蛋白激酶等酶相比，KMT酶导致癌症的机制知之甚少。该研究的总体目标是阐明新发现的甲基转移酶（SETD 5）在胰腺癌发生中的生物学功能，并开发一种新的联合治疗方法，该方法显示协同效应，从而降低药物剂量，更好的耐受性和降低的治疗抗性。首先，我将在已建立的胰腺癌小鼠模型中分析SETD 5在癌症发生和癌前病变进展中的作用。接下来，将评估SETD 5在肿瘤维持中的功能。我将在KRAS突变胰腺癌细胞系中删除或过表达SETD 5，并分析SETD 5是否影响增殖、细胞死亡、迁移、侵袭或转移扩散。使用一个创新的小鼠模型，其中SetD 5将被删除时，胰腺肿瘤已经发展，我将调查的功能，SETD 5在癌症维持在体内。存活率和肿瘤负荷以及组织分析将证明SETD 5消融是否在这些小鼠中产生有益的表型。将在体内分析MEK 1/2和SET D5组合疗法的协同作用。这些实验将揭示SETD 5是否具有临床相关功能，以及已经发展为胰腺癌的患者是否会从抑制SETD 5中受益。为了找到SETD 5靶点并阐明其生物学功能，我将进行组蛋白肽微阵列，然后进行体外甲基转移酶测定。RNA测序以及染色质IP将揭示哪些基因在SETD 5丢失后受到差异调节，哪些启动子区域受到SETD 5结合的影响。随后使用CRISPR/Cas9技术进行的基因组编辑将用于验证所鉴定的SETD 5靶标的生物学意义。这些发现将提供关于SETD 5功能的新知识，并将允许在体内快速分析SETD 5靶标。这项研究将为甲基转移酶在胰腺癌的发展和治疗中的作用提供实质性的新见解，并可能有助于确定新的有希望的候选治疗靶点。因此，这项研究将有力地推动癌症生物学和信号传导领域的发展。

Pancreatic cancer is a devastating disease and despite intensive research during the last 30 years, the 5-year survival rate of pancreatic cancer remains constantly low. This is primarily due to the late diagnosis and due to ineffective therapy options. While targeted therapies directed against kinases of the Ras signaling pathway have shown promising effects in vitro and in vivo they remained largely ineffective in clinical trials due to high toxicity, low efficacy and development of therapy resistance. Lysine methyltransferases (KMTs), which perform posttranslational modifications, have emerged as potential key regulators of cancer pathways. In comparison to enzymes like protein kinases that have well-established roles in tumorigenesis, the mechanisms by which KMTs enzymes contribute to cancer are poorly understood.The overall goal of the study is to elucidate the biological function of a newly identified methyltransferase (SETD5) in pancreatic carcinogenesis and to develop a new combination therapy that shows synergistic effects that will result in lower doses of drugs, better tolerance and reduced therapy resistance. First, I will analyze the role of SETD5 in cancer initiation and progression of precancerous lesions in an established mouse model of pancreatic cancer. Next, the function of SETD5 in tumor maintenance will be assessed. I will delete or overexpress SETD5 in KRAS mutant pancreatic cancer cell lines and analyze if SETD5 impacts proliferation, cell death, migration, invasion or metastatic spread. Using an innovative mouse model in which SetD5 will be deleted when pancreatic tumors have already developed, I will investigate the function of SETD5 in cancer maintenance in vivo. Survival and tumor burden as well as analysis of the tissue will demonstrate if SETD5 ablation results in a beneficial phenotype in these mice. Synergistic effects of a MEK1/2 and SETD5 combination therapy will be analyzed in vivo. These experiments will reveal if SETD5 has a clinically relevant function and if patients who already have developed pancreatic cancer would benefit from inhibiting SETD5. To find SETD5 targets and elucidate its biological function, I will perform a Histone Peptide Microarray followed by in vitro methyltransferase assays. RNA sequencing as well as chromatin IP will reveal which genes are differentially regulated upon SETD5 loss and which promoter regions are affected by SETD5 binding. Subsequent genome editing using the CRISPR/Cas9 technique will be used to validate the biological significance of the identified SETD5 targets. These findings will provide new knowledge of SETD5 function and will allow to analyze SETD5 targets quickly in vivo. This study will provide substantial new insights into the role of methyltransferases in the development and therapy of pancreatic cancer and might help to identify new promising candidate therapeutic targets. Thereby, this study will strongly advance the fields of cancer biology and signaling.