The Role of EZH2 in Non-Muscle Invasive Bladder Cancer

膀胱癌是男性第四常见的癌症，对退伍军人和VHA来说是一个沉重的负担 由于吸烟和暴露于部署的高复发率和进展率- 相关致癌物质。近80%的膀胱癌不侵犯膀胱壁的肌肉(称为 肌肉浸润性膀胱癌(NMIBC)，但最具侵袭性的肿瘤将进展为肌肉 侵袭伴淋巴结转移导致30%的患者死亡。死亡的主要原因是 膀胱癌对治疗具有抵抗力，因为这些浸润性癌获得了细胞可塑性和干细胞- 就像房产一样。确定调节细胞分化这种侵袭性变化的机制 表型是癌症的一个标志，也是由基因突变和基因突变共同调节的分化的重大转变 表观遗传细胞重编程。我们研究的长期目标是研究分子和 表观遗传途径驱动膀胱癌的侵袭。通过了解这些机制，我们可能会开发出 膀胱癌患者合理而新颖的治疗方法。为了研究表观遗传机制， 有助于膀胱癌的侵袭和增殖作为一个可行的靶点，我们评估了组蛋白 Zust-2甲基转移酶增强子(EZH2)，作为多梳抑制物复合体-2(PRC-2)的一部分，在 膀胱癌。我们的初步数据显示，EZH2及其组蛋白靶标的表达增加， H3K27me3，在致癌物诱导的膀胱癌小鼠模型中。在多种膀胱癌细胞系中， 与未转化的尿路上皮细胞相比，EZH2的表达增加。PRC-2的不稳定 复合体可以阻止细胞增殖。与我们的发现一致，多个人类的生物信息学分析 膀胱癌数据库显示EZH2在浸润性膀胱癌中过表达，我们 在所有阶段的膀胱癌患者的肿瘤标本中都得到了证实。根据这些初步数据， 我们的中心假设是，EZH2通过引起组蛋白的全球变化来推动膀胱癌的侵袭 甲基化通过上皮细胞向侵袭性和干细胞样表型转变 间充质转化。因此，鉴于我们有希望的初步数据，我们建议调查我们的假设 具体目标如下：1)确定EZH2在膀胱癌发生发展中的作用；2) 研究EZH2基因在膀胱癌EMT、侵袭和干细胞基因中的异常甲基化；3) 评价EZH2治疗膀胱癌的药理抑制作用。目前，我们没有 膀胱癌的个性化遗传或表观遗传靶点和我们对非肌肉侵袭性的最佳治疗 膀胱癌已经40岁了。通过多学科协作，我们已经证明了可行性 用我们的方法。成功完成本提案中所述的研究将提供一个创新的 既研究膀胱癌侵袭机制又利用一种新的 治疗膀胱癌的方法。这些以EZH2为靶标的药物克服了细胞 并进行临床前研究，以便接触患有膀胱癌的退伍军人。

Bladder cancer is the fourth most common cancer in men and a significant burden for Veterans and the VHA due to the high frequency of recurrence and progression linked to smoking and exposure to deployment- related carcinogens. Nearly 80% of bladder cancers do not invade the muscle of the bladder wall (called “non- muscle invasive bladder cancer”, NMIBC) but the most aggressive of these tumors will progress to muscle invasion with lymph node metastasis resulting in death in 30% of patients. The primary cause of death from bladder cancer is resistance to therapy as these invasive carcinomas acquire cellular plasticity and stem cell- like properties. Identification of mechanisms that regulate this change in cellular differentiation This invasive phenotype is a hallmark of cancer and a major shift in differentiation regulated by both genetic mutations and epigenetic cellular reprogramming. The long-term goal of our research is to investigate the molecular and epigenetic pathways driving invasion of bladder cancer. By understanding these mechanisms, we may develop rational and novel therapeutics for patients with bladder cancer. To investigate the epigenetic mechanisms that contribute to invasion and proliferation as a feasible target for bladder cancer, we evaluated the histone methyltransferase Enhancer of Zeste-2 (EZH2), as part of the polycomb repressor complex-2 (PRC-2) in bladder cancer. Our preliminary data demonstrate increased expression of EZH2 and its histone target, H3K27me3, in a carcinogen-induced mouse model of bladder cancer. In multiple bladder cancer cell lines, EZH2 expression is increased compared to non-transformed urothelial cells. Destabilization of the PRC-2 complex stops cellular proliferation. Consistent with our findings, bioinformatics analysis of multiple human bladder cancer databases demonstrate that EZH2 is overexpressed in invasive bladder cancers, which we have confirmed in tumor specimens from patients with all stages of bladder cancer. Given this preliminary data, our central hypothesis is that EZH2 drives invasion of bladder cancer by causing global changes in histone methylation that shifts cellular identity to an invasive and stem cell-like phenotype via an epithelial to mesenchymal transition. Thus, given our promising preliminary data, we propose to investigate our hypothesis with the following Specific Aims: 1) Determine the role of EZH2 in bladder cancer initiation and progression; 2) Investigate aberrant histone methylation of EMT, invasive and stem cell genes by EZH2 in bladder cancer; 3) Evaluate pharmacologic inhibition of EZH2 as a treatment for bladder cancer. Currently, we have no personalized genetic or epigenetic targets for bladder cancer and our best therapy for non-muscle invasive bladder cancer is > 40 years old. Through multi-disciplinary collaboration we have demonstrated feasibility with our approach. Successful completion of the studies described in this proposal will provide an innovative approach to both investigate the mechanisms involved in the invasion of bladder cancer and utilize a novel therapeutic approach to treat bladder cancer. These EZH2-targeted agents overcome the challenge of cellular resistance and have pre-clinical investigations that will allow access to Veterans with bladder cancer.