Restoring ciliogenesis as a novel approach to blocking breast cancer growth

项目摘要 初级纤毛是大多数静止和分化细胞表面的触角状结构， 对于转导生长控制所需的信号（包括Hedgehog（Hh）信号）至关重要。因此，委员会认为， 纤毛的丧失改变了对细胞外信号的反应性。许多癌症，包括乳腺癌，表现出近- 在致癌转化的早期阶段纤毛完全丧失。新战略迫切需要 需要治疗最致命的亚型，三阴性乳腺癌（TNBC）。TNBC不成比例地 在非洲裔美国人中观察到，因此代表了一个关键的健康差距。我们建议恢复 纤毛发生对乳腺癌细胞的作用将恢复生长抑制信号传导并阻断肿瘤生长。 我们的初步数据表明：（1）癌细胞可以再生纤毛;（2）单基因或药物 干预可导致癌细胞重新生长纤毛;和（3）纤毛重新生长抑制增殖。我们将 在这些发现的基础上，进行一项创新的功能性筛选，以确定限制基因表达的基因。 在乳腺癌细胞中的纤毛发生，并测试恢复纤毛发生是否限制体内肿瘤生长。 已确定的纤毛生成抑制剂将有助于阐明癌细胞 抑制纤毛生成，确定纤毛如何抑制乳腺细胞增殖，并首次测试， 逆转纤毛相关信号传导的丧失恢复了对转化的乳腺癌细胞的生长调节。 在目标1中，我们将进行一种新的全基因组筛选，以确定乳腺癌中纤毛发生的抑制剂。 先前的筛选已经鉴定了促进纤毛发生的调节剂。相比之下，我们的屏幕将识别负 纤毛装配的调节器。我们还将测试创新的假设，即纤毛的恢复组合 使用临床相关的纤毛信号传导抑制剂可以阻断肿瘤生长。在目标2中，我们将测试如何 恢复纤毛发生影响动物模型中的乳腺癌生长。这些研究将揭示 癌细胞限制纤毛发生，纤毛发生是癌细胞生物学中一个重要的、未回答的问题。成功 证明恢复纤毛发生抑制肿瘤生长将揭示一种新的策略， 针对乳腺癌，这可能适用于其他癌症类型。通过利用 Dynlacht和Reiter实验室的优势互补，我们将创新性地将联合收割机RNAi 筛选、最先进的纤毛分析和有机体癌症建模。虽然具有高度探索性，但在 根据R21的作用机制，探索促进纤毛生成和抑制乳腺癌的途径 生长将确定肿瘤避免生长控制的新方式，并可能建立一个新的范式， 治疗乳腺癌此外，为了解决癌症健康差距，我们将：（1）开始奠定 理解为什么TNBC不成比例地影响非洲裔美国人的机械基础和（2） 获取并表征原发性TNBC样品，以确定肿瘤纤毛形成或TNBC的表达， 纤毛发生的调节因子在不同种族人群中不同。 !

PROJECT SUMMARY The primary cilium, an antenna-like structure on the surface of most quiescent and differentiated cells, is essential for transducing signals required for growth control, including Hedgehog (Hh) signals. Consequently, loss of cilia alters responsiveness to extracellular cues. Many cancers, including breast cancer, exhibit near- complete loss of cilia during the early stages of oncogenic transformation. Novel strategies are urgently needed to treat the most lethal sub-type, triple-negative breast cancer (TNBC). TNBC is disproportionately observed in African-Americans and thus represents a key health disparity. We propose that restoring ciliogenesis to breast cancer cells will restore growth suppressive signaling and block tumor growth. Our preliminary data indicate that (1) cancer cells can regrow cilia; (2) single gene or pharmacological intervention can cause cancer cells to regrow cilia; and (3) ciliary regrowth inhibits proliferation. We will build on these findings by conducting an innovative functional screen to identify the genes that restrict ciliogenesis in breast cancer cells, and test whether restoring ciliogenesis limits tumor growth in vivo. The identified ciliogenesis inhibitors will help unravel the molecular mechanisms by which cancer cells suppress ciliogenesis, identify how cilia inhibit breast cell proliferation, and test, for the first time, whether reversing the loss of cilium-associated signaling restores growth regulation to transformed breast cancer cells. In Aim 1, we will perform a novel genome-wide screen to identify inhibitors of ciliogenesis in breast cancer. Prior screens have identified regulators that promote ciliogenesis. In contrast, our screen will identify negative regulators of cilium assembly. We will also test the innovative hypothesis that restoration of cilia in combination with use of clinically relevant inhibitors of ciliary signaling can block tumor growth. In Aim 2, we will test how restoring ciliogenesis impacts breast cancer growth in animal models. Together, these studies will reveal how cancer cells restrict ciliogenesis, an important, unanswered question in cancer cell biology. The successful demonstration that restoring ciliogenesis inhibits tumor growth will reveal a novel strategy for targeting breast cancer, which may be applicable to other cancer types. By taking advantage of the complementary strengths of the Dynlacht and Reiter laboratories, we will innovatively combine RNAi screening, state-of-the-art ciliary analysis, and organismal cancer modeling. While highly exploratory, in keeping with the R21 mechanism, discovering the means to promote ciliogenesis and restrain breast cancer growth will identify novel ways that tumors avoid growth control and may establish a novel paradigm for treating breast cancer. Furthermore, to address cancer health disparities, we will: (1) begin to lay the mechanistic foundation for understanding why TNBC disproportionately affects African-Americans and (2) acquire and characterize primary TNBC samples to determine whether tumor ciliation or expression of regulators of ciliogenesis differs in different ethnic populations. !