Proliferation and Differentiation of Bladder Epithelial Cells in Regeneration and Malignancy

项目总结/摘要 作为深入了解癌症发生和发展机制的策略，我们 研究了损伤后的增殖反应及其与恶性生长的关系， 一个主要的焦点。膀胱癌是男性中第四大最常见的癌症，女性中第十二大，并且是侵袭性的。 膀胱癌如果不治疗是致命的。局部手术切除后往往会复发：这 和高风险的进展一起需要不断监测，这是成本的主要因素， 膀胱癌治疗，这是所有癌症患者中最高的。 我们最近的研究表明，膀胱的基础Sonic hedgehog（Shh）表达细胞 上皮（尿路上皮）作为干细胞发挥功能，支持所有尿路上皮细胞的再增殖和更新 类型的膀胱损伤，如尿路感染（UTI）引起的。这种损伤反应是 由膀胱上皮基底干细胞产生的Shh蛋白增加触发，这反过来触发了 在基质的亚细胞中产生Wnt和Bmp蛋白;这些基质生态位信号反过来驱动 尿路上皮干细胞及其后代的增殖和分化。我们还发现嘘- 表达基底干细胞是最致命形式的膀胱癌，浸润性尿路上皮癌的起源细胞。 癌（IUC），并且对于其上皮限制的前体病变，原位癌（CIS）。 在上一个奖项期间，我们做出了令人惊讶的发现，CIS病变，虽然 局限于上皮细胞，可通过单个基底干的克隆性扩张而遍布整个尿道 细胞，表明CIS细胞的积极增殖性质。我们还发现Shh诱导的基质 促进终末尿路上皮分化的信号构成了膀胱癌进展的主要障碍， 局限于上皮的侵袭性疾病（CIS至IUC）。在目前的提案中，我们的目标是：（一）描述 组织动力学和调节基础的短暂与持续增殖状态的损伤反应， 与原位癌相比;（ii）识别控制膀胱癌终末分化的调节信号 上皮细胞;和（iii）表征分化丧失背后的遗传和表观遗传变化- 在从非侵入性疾病进展到侵入性疾病（CIS到IUC）期间诱导信号。 这项工作将为改善CIS的诊断提供基础，并可能提供抑制靶点。 CIS细胞的持续增殖状态。此外，这项工作可能为阻断 通过给予促分化信号（可能包括FDA- 批准的药物，如FK506和维甲酸，或通过阻断或逆转基础的变化， 分化信号的产生。这项工作可能会超越膀胱癌扩展到其他内胚层肿瘤。 恶性肿瘤，如胰腺导管腺癌和结肠腺癌，其中Shh诱导的 基质信号也抑制癌生长。

PROJECT SUMMARY/ABSTRACT As a strategy to gain insight into the mechanisms of cancer initiation and progression, we have studied the proliferative response to injury and its relationship to malignant growth, with the urinary bladder as a major focus. Bladder cancer is the fourth most prevalent cancer in men, twelfth in women, and invasive bladder cancer is uniformly lethal left untreated. Local surgical excision is often followed by recurrence: this and the high risk of progression together require constant monitoring, a major contributor to the cost of bladder cancer treatment, which is the highest per patient for any cancer. Our recent work has shown that basal Sonic hedgehog (Shh)-expressing cells of the bladder epithelium (urothelium) function as stem cells that support the repopulation and renewal of all urothelial cell types in response to bladder injury such as that caused by urinary tract infection (UTI). This injury response is triggered by increased Shh protein production from basal stem cells of bladder epithelium, which in turn triggers production of Wnt and Bmp proteins in subjacent cells of the stroma; these stromal niche signals in turn drive proliferation and differentiation of urothelial stem cells and their progeny. We also showed that Shh- expressing basal stem cells are the cell-of-origin for the most lethal form of bladder cancer, invasive urothelial carcinoma (IUC), and for its epithelially-confined precursor lesion, carcinoma in situ (CIS). During the previous award period we made the surprising discovery that the CIS lesion, although epithelially-confined, can spread throughout the entire urothelium by clonal expansion of a single basal stem cell, indicating the aggressively proliferative nature of CIS cells. We also found that Shh-induced stromal signals that promote terminal urothelial differentiation constitute the major barrier to progression from epithelially-confined to invasive disease (CIS to IUC). In the current proposal, we aim to: (i) characterize the tissue dynamics and regulatory basis of transient vs. persistent proliferative states in injury response as compared to carcinoma in situ; (ii) identify the regulatory signals that control terminal differentiation of bladder epithelial cells; and (iii) characterize the genetic and epigenetic changes underlying the loss of differentiation- inducing signals during progression from non-invasive to invasive disease (CIS to IUC). This work will provide the basis for improved diagnosis of CIS and may provide targets for suppression of the persistently proliferative state of CIS cells. In addition, this work may provide the basis for blocking progression to invasive disease by administration of pro-differentiation signals, potentially including FDA- approved drugs such as FK506 and retinoic acid, or by blocking or reversing the changes that underlie the loss of differentiation signal production. This work may extend beyond bladder cancer to other endodermal malignancies, such as pancreatic ductal adenocarcinoma and colon adenocarcinoma, in which Shh-induced stromal signals also restrain cancer growth.