Exploiting the epithelial-to-mesenchymal transition for the differentiation of cancer stem cells

项目摘要 大约15-20%的乳腺癌患者属于基底细胞样类型，这代表了一种不同的亚型 其特征是肿瘤更具侵袭性，预后较差。死于这些 癌由疾病向远处的转移性扩散和治疗抗性引起， 导致癌症复发为更难控制的侵袭性形式。这两个属性 是由于它们的细胞异质性，这种异质性通过各种机制产生，包括克隆进化， 以及癌症干细胞（CSC）的存在。上皮细胞向间质细胞转化（EMT）是一个程序， 我们已经证明它是产生具有CSC样特性的细胞的原因。 我们目前的建议旨在通过诱导间充质干细胞向间充质干细胞分化， 上皮转化（MET）。为了做到这一点，我们进行了筛选，以确定能够 诱导上皮细胞/非CSC状态的标志--E-钙粘蛋白的转录， 间充质/CSC样。通过这种筛选，我们确定了毛喉素，cAMP的激活剂，能够诱导 E-钙粘蛋白转录和间充质/CSC向更良性上皮状态的逆转。通过 本研究旨在揭示cAMP升高剂诱导MET的机制 通过完整表征信号传导的重要下游组分，即蛋白激酶A， (PKA)及其下游底物。我们还旨在了解发生的表观遗传重编程 在通过组蛋白修饰酶PHF 2的功能激活PKA之后。这两个 这些组成部分将解决CSC可以分化为使它们呈现出某种状态的机制 对化疗剂如阿霉素治疗高度敏感。 尽管经过二十多年的研究，我们仍然缺乏特异性靶向CSC的能力。通过学习 磷酸二酯酶和G蛋白偶联受体（GPCR）调节cAMP水平，我的目标是 开发特异性诱导CSC分化的方法，这些分化可以转化为治疗效用。

Project Summary About 15-20% of breast cancer patients fall under the basal-like category, which represent a diverse subtype that is characterized by tumors that are more aggressive conferring poor prognosis. Deaths from these carcinomas result from metastatic spread of the disease to distant sites and from therapeutic resistance, which results in the relapse of cancers into more aggressive forms that are difficult to contain. Both these properties are attributed to their cellular heterogeneity that arises through various mechanisms including clonal evolution and the presence of cancer stem cells (CSCs). The epithelial-to-mesenchymal transition (EMT) is one program that we have shown to be responsible for the generation of cells that have CSC-like properties. Our current proposal aims to induce differentiation of these CSCs through the induction of a mesenchymal-to- epithelial transition (MET). To do this, we carried out a screen to identify compounds that are capable of inducing the transcription of E-cadherin, a hallmark of the epithelial/non-CSC state, in cells that are more mesenchymal/CSC-like. Through this screen we identified Forskolin, an activator of cAMP, to be able to induce E-cadherin transcription and a reversion of the mesenchymal/CSCs to a more benign epithelial state. Through this proposal we aim to uncover the mechanism by which cAMP-elevating agents are able to induce an MET by complete characterization of the essential downstream components of signalling, namely Protein Kinase A (PKA) and its downstream substrates. We also aim to understand the epigenetic reprogramming that occurs following activation of PKA through the functions of the histone-modifying enzyme PHF2. Both these components will address the mechanisms by which CSCs can be differentiated to a state that renders them highly sensitive to treatment with chemotherapeutic agents such as doxorubicin. Despite over two decades of research, our ability to specifically target CSCs is still lacking. Through the study of Phosphodiesterases and G-Protein Coupled Receptors (GPCRs) that modulate cAMP levels, I aim to develop ways to specifically induce differentiation of CSCs that can be translated for therapeutic utility.