Dissecting the role of extra centrosomes-induced exosome secretion in PDAC microenvironment

尽管取得了进展，癌症仍然是医学上的一个严重挑战。胰腺癌尤其如此，其5年生存率<5%。这种高度侵袭性的行为部分是由纤维化引起的，纤维化在肿瘤周围形成障碍，阻碍药物输送和疗效。这种屏障是由肿瘤诱导的称为星状细胞的细胞群的变化引起的。因此，对抗胰腺癌中的纤维化被认为是治疗干预的重要领域。我们最近发现，一群癌细胞携带一种叫做中心体的细胞器的扩增，能够激活星状细胞。中心体扩增是一种存在于癌细胞中的畸变，在19世纪后期被描述为肿瘤发生的可能原因。我们现在知道，这些异常是人类肿瘤的共同特征，并且可以积极促进肿瘤形成。我们实验室发表的工作是第一个确定这些异常在影响周围细胞中的新功能（Arnandis等人，2018年）。这项工作表明，具有扩增的中心体的癌细胞在肿瘤发生中的作用比以前预期的更广泛，因为它可以交流和改变肿瘤内的其他细胞。特别是我们新的未发表的数据表明，具有额外中心体的癌细胞与胰腺星状细胞之间的这种通信导致它们的激活，这可能有助于PDAC中的纤维化。这是通过从具有额外中心体（外泌体）的细胞中释放小泡来介导的，外泌体中充满了指示星状细胞被激活的因子。因此，了解具有额外中心体的细胞如何激活星状细胞可以帮助理解纤维化并导致治疗胰腺癌患者的治疗策略。在这项研究中，我们的目标是确定中心体扩增如何诱导外泌体的释放，进而这些囊泡如何激活星状细胞。我们将使用多种方法的组合，包括活细胞成像，以确定负责外泌体释放的机制。此外，使用成熟的方法来识别这些外泌体中包含的因子，我们建议揭示负责星状细胞激活的分子。我们将使用模拟肿瘤中癌症和星状细胞之间相互作用的3-D培养模型来测试阻断所识别的因子是否可以防止星状细胞活化和纤维化。还将研究星状细胞中外来体诱导的信号传导的变化，以了解激活的机制。这对于识别胰腺肿瘤中星状细胞活化和纤维化的特征可能很重要，并将为识别潜在的治疗靶点以阻断纤维化提供另一个机会。最后，我们将使用小鼠模型在体内测试我们的发现。这将提供相关的临床前模型，以评估我们的研究结果和测试对治疗的反应的重要性。因此，我们的工作不仅有助于首次了解中心体扩增在肿瘤微环境中的作用，而且还可能对开发靶向纤维化治疗胰腺癌患者的治疗策略产生重大影响。

Despite progress, cancer is still a serious challenge in medicine. This is particularly true for pancreatic cancer, which has a dismal 5-year survival rate of <5%. This highly aggressive behaviour is cause in part caused by fibrosis, which forms a barrier around the tumour that hinders drug delivery and efficacy. This barrier is cause by changes in a cell population, named stellate cells, induced by the tumour. Combating fibrosis in pancreatic cancer is thus considered to be an important area for therapeutic intervention. We recently found that a population of cancer cells that carries amplification of a cellular organelle called centrosome is able to activate stellate cells. Centrosome amplification, an aberration that exists in cancer cells, was described in later 1800s as a possible cause of tumourigenesis. We now know that these abnormalities are a common feature of human tumours and can actively contribute to tumour formation. Published work from our lab was the first to identify a novel function of these abnormalities in influencing the surrounding cells (Arnandis et al., 2018). This work demonstrates that cancer cells with amplified centrosomes have a broader role in tumourigenesis than previously anticipated by communicating and changing other cells within tumours. In particular our new unpublished data shows that this communication between cancer cells with extra centrosomes and pancreatic stellate cells leads to their activation, which could contribute to fibrosis in PDAC. This is mediated via the release of small vesicles from cells with extra centrosomes, exosomes, that are packed with factors that will instruct stellate cells to become activated. Thus, understanding how cells with extra centrosomes activate stellate cells could help understanding fibrosis and lead to therapeutic strategies to treat pancreatic cancer patients.In this research proposal we aim to determine how centrosome amplification induces the release of exosomes and in turn how these vesicles activate stellate cells. We will use a combination of approaches, including live cell imaging, to identify the mechanisms responsible for exosome release. Furthermore, using well-established methods to identify the factors contained in these exosomes, we propose to uncover the molecules responsible for stellate cell activation. We will test if blocking the identified factors prevents stellate activation and fibrosis using 3-D culture models that mimic the interaction between cancer and stellate cells in tumours. Changes in signalling induced by exosomes in stellate cells will also be studied to understand the mechanisms of activate. This could be important to identify signatures of stellate cell activation and fibrosis in pancreatic tumours and will provide another opportunity to identify potential therapeutic targets to block fibrosis. Finally, we will use mouse models to test our findings in vivo. This will provide relevant pre-clinical models to assess the importance of our findings and test response to therapy. Thus, our work will not only contribute to understand for the first time the role of centrosomes amplification in tumour microenvironment but could also have a major impact in developing therapeutic strategies that target fibrosis to treat patients that suffer from pancreatic cancer.