P5: Dissection of KMT9 biology in urothelial carcinoma

表观遗传的作家，如组蛋白甲基转移酶在生理和病理的控制中发挥关键作用。我们的预备数据建立了组蛋白甲基转移酶KMT 9的生物学相关性，并将KMT 9鉴定为膀胱癌治疗干预的有希望的靶点。我们解决了KMT 9的晶体结构，实施了结构指导的KMT 9抑制剂计划，并开发了药物样小分子KMT 9抑制剂（KMT 9 i）。KMT 9 i显示出对所有目前已知的SET结构域和7-β链组蛋白甲基转移酶的选择性，在生物化学和细胞测定中的高效力，并且严重损害膀胱癌细胞的生长。为了促进KMT 9抑制的途径在膀胱癌中的临床I期测试，我们建议使用小鼠遗传学和小分子KMT 9抑制剂来联合收割机体内分析，以询问体内和类器官培养系统中膀胱癌遗传学的特定方面。这种详细的分析将大大提高我们对KMT 9在膀胱癌中功能的理解，并提供KMT 9作用的全面观点。特别是，我们将揭示KMT 9对致癌的PTEN信号传导和TP 53的细胞周期调控的影响。因此，我们的目的是（1）在体外和体内评估Pten/Trp 53缺失（Pten/Trp 53 KO）膀胱癌模型中Kmt 9-α丢失（KMT 9 KO）和抑制（KMT 9 i）的治疗潜力。此外，我们建议（2）解剖和KMT 9在正常膀胱和尿路上皮癌中作用的不同机制基础。与其他UcarE小组的合作将使我们能够将小鼠研究中的发现转化为人类膀胱癌样本，类器官和细胞系，并对我们的KMT 9抑制剂进行广泛的临床前测试。该建议将拓宽我们对KMT 9抑制用于治疗干预的效用的知识和观点，并提供对KMT 9生物学的高级机制理解。

Epigenetic writers such as histone methyltransferases play key roles in the control of physiology and pathology. Our preparatory data establish the biological relevance of the histone methyltransferases KMT9 and identify KMT9 as a promising target for therapeutic intervention of bladder cancer. We solved the crystal structure of KMT9, implemented a structure-guided KMT9 inhibitor programme and developed drug-like small molecule KMT9 inhibitors (KMT9i). KMT9i display selectivity against all currently known SET-domain and 7-beta-strand histone methyltransferases, high potency in biochemical and cellular assays, and severely impair growth of bladder cancer cells. To promote the path of KMT9 inhibition to clinical phase I testing in bladder cancer, we propose to combine in vivo analyses using mouse genetics and small-molecule KMT9 inhibitors to interrogate specific aspects of the genetics of bladder cancer in vivo and in organoid culture systems. This detailed analysis will greatly enhance our understanding of KMT9 function in bladder cancer and provide a comprehensive view of KMT9 action. In particular, we will uncover the impact of KMT9 on oncogenic PTEN signalling and cell cycle regulation by TP53. Consequently, we aim (1) to evaluate the therapeutic potential of Kmt9-alpha loss (KMT9 KO) and inhibition (KMT9i) in the Pten/Trp53 deletion (Pten/Trp53 KO) bladder cancer model in vitro and in vivo. Furthermore, we propose (2) to dissect and the different mechanistic underpinnings of KMT9 action in normal bladder and urothelial carcinoma. Collaborations with the other UcarE groups will allow us to translate the findings made in our mouse studies to human bladder cancer samples, organoids and cell lines, as well as to carry out extensive pre-clinical testing of our KMT9 inhibitors. This proposal will broaden our knowledge and the perspectives on the utility of KMT9 inhibition for therapeutic intervention and provide advanced mechanistic understanding of KMT9 biology.