Using patient-led genetics to identify new therapeutic targets in metastatic cholangiocarcinoma

胆管癌（CCA）包括一组异质性恶性肿瘤，可出现在胆道树的每一点。在世界范围内，CCA的发病率（约5:100,000）正在上升，CCA已经是第二大常见的原发性肝脏肿瘤，约占所有胃肠道癌症的3%。值得注意的是，在过去二十年中，欧洲登记的死亡人数增加了37%，这使CCA成为一个主要的健康、社会和经济负担。CCA通常在早期无症状，通常在晚期诊断，此时大多数患者有转移性疾病。这种情况极大地损害了主要基于手术或肝移植的潜在治疗选择，并明显影响到全世界所有卫生系统。此外，肿瘤复发的高风险和cca化疗耐药的升高导致预后不良。一线化疗包括吉西他滨和顺铂的联合，这是姑息性的，单独增加患者12个月的总生存期。CCA的发病机制在很大程度上仍不清楚。在分子水平上，CCA是一种遗传异质性疾病，虽然已经发现了少量驱动突变，但三分之一的患者不包含可治疗的突变，而对于其余三分之二的患者，针对这些突变的靶向治疗效果有限。提出的工作将检查转移性CCA的分子基础，并确定CCA的遗传多样性如何塑造多样化的肿瘤微环境。使用全外显子组测序将确定CCA患者来源的循环肿瘤细胞（CTC）中的候选“转移驱动”突变。将进行一种创新的体内CRISPR筛选方法，在小鼠中产生含有“转移驱动因素”突变的原发肿瘤，并评估这些驱动因素在体内启动CCA转移的潜力。我们将利用这些信息来确定不同的突变如何影响癌细胞和肿瘤微环境之间的相互作用，并最终使肿瘤变得易于转移。这项工作将大大增加我们对CCA功能遗传学的理解，并可能为未来治疗具有不同基因组谱的转移性CCA的新靶标途径的鉴定。此外，它有望确定广泛适用的转移原理，可以在其他癌症中进行测试。最终，通过了解基因变化如何相互作用来塑造肿瘤的结构，我们将更好地调节这些过程以获得治疗效果。

Cholangiocarcinoma (CCA) includes a heterogeneous group of malignancies that can emerge at every point of the biliary tree. Incidence (~5:100,000) is rising worldwide and CCA already represents the second most frequent primary liver tumour and ~3% of all gastrointestinal cancers. Noteworthy, a 37% increase in deaths were registered in Europe in the past two decades, which makes CCA a major health, social and economic burden. CCA is generally asymptomatic in early stages and is commonly diagnosed in advanced phases, when the majority of patients have metastatic disease. This circumstance extremely compromises the potential curative options mainly based on surgery or liver transplantation and clearly impacts on all the health systems worldwide. Moreover, the high risk of tumour recurrence and the elevated chemoresistance of CCAs contribute to poor prognosis. The first line chemotherapy includes the combination of gemcitabine and cisplatin, which is palliative and solely increases patients overall survival in 12 months. The etiopathogenesis of CCA remains largely unknown. At the molecular level, CCA is a genetically heterogeneous disease and whilst a small number of driver-mutations have been found, one-third of patients do not contain therapeutically actionable mutations and for the remaining two-thirds that do, targeted therapies against these mutations have limited efficacy. The proposed work will examine the molecular basis of metastatic CCA and determine how genetic diversity in CCA sculpts a diverse tumour microenvironment. Using whole exome sequencing candidate "metastatic driver" mutations in CCA patient-derived circulating tumour cells (CTC) will be identified. An innovative in vivo CRISPR screening method to generate primary tumours containing mutations in "metastatic drivers" in the mouse will be performed, and the potential of these drivers to initiate CCA metastasis in vivo will be assessed. We will use the information here to identify how distinct mutations affect the interactions between cancer cells and the tumour microenvironment, and ultimately allow a tumour to become permissive to metastasis. This work should substantially increase our understanding of the functional genetics in CCA, as well as the likely identification of novel target pathways for future therapeutic development in metastatic CCA with diverse genomic profiles. Furthermore, it is expected to identify broadly applicable principles of metastasis that can be tested in other cancers. Ultimately, by understanding how genetic changes interact to shape the architecture of a tumour, we will be better placed to modulate these processes for therapeutic benefit.