GPCRs: novel targets in cancer-associated fibroblasts

描述（由申请人提供）：胰腺癌，特别是胰腺导管腺癌（PDAC），是美国癌症死亡的第四大原因，5年生存率约为5%。这种不良存活率的一个关键因素是PDAC的广泛结缔组织增生（丰富的纤维化基质），这可能使手术切除肿瘤变得困难，并可能限制治疗药物进入肿瘤细胞。癌相关成纤维细胞（CAF），肌纤维母细胞样细胞，产生细胞外基质蛋白，是负责结缔组织增生的PDAC。胰腺星状细胞（PSC）和成纤维细胞（PF）是CAF的关键祖细胞。阻断CAFs的表达和活性可能有助于PDAC的治疗和预后。该提案假设G蛋白偶联受体（GPCR）是胰腺CAF的一个重要但尚未充分研究的方面，并且可能是治疗胰腺癌的新靶点。GPCR是细胞表面信号受体的最大家族（占人类基因组的3%），并调节许多生理过程。作为质膜蛋白，GPCR可从细胞外空间进入; GPCR在细胞类型和组织上选择性表达，并在配体相互作用因子中显示特异性，这有助于解释为什么GPCR是约30%的当前治疗药物的靶标，尽管不是肿瘤学中的靶标。该R21旨在通过鉴定、定量和验证人胰腺CAF的GPCR表达，以及通过评估CAF选择性表达的GPCR的治疗潜力（与PSC和PF相比）来实现变革。该项目使用患者来源的胰腺CAF作为模型，并将使用几种基因组策略：一种GPCR组学方法来定量所有非化学感受性GPCR的基因表达，使用RNA干扰敲低CAF表达的GPCR，并鉴定介导关键功能反应和获得性免疫应答的GPCR。通过使用正常的胰腺成纤维细胞或胰腺星状细胞进行功能研究，并通过以下方法试图重现CAF的纤维化表型：增强PSC和PF中GPCR的表达。目标是使用基因组方法来鉴定GPCR作为胰腺癌治疗的潜在靶点，通过其阻断CAF表达和促纤维化活性的能力。我们将采用的策略-GPCR基因家族成员的GPCRomics以及该家族成员在人类疾病中（在这种情况下，在胰腺癌相关成纤维细胞中）的功能获得和功能丧失研究-是一种新的策略，应该很容易适用于其他癌症和其他疾病环境中的CAF。此外，该提议的另一个新的和临床上重要的方面是其开始努力测试CAF（特别是胰腺CAF）上的GPCR可能是迫切需要新疗法的疾病的可药物化靶标的想法。

DESCRIPTION (provided by applicant): Pancreatic cancer, in particular pancreatic ductal adenocarcinoma (PDAC), is the fourth leading cause of cancer death in the U.S. and has a 5-year survival of ~ 5%. A key contributor to this poor survival is the extensive desmoplasia (abundant fibrotic stroma) of PDAC, which can make it difficult to surgically remove the tumor and can limit access of therapeutic drugs to the tumor cells. Cancer-associated fibroblasts (CAFs), myofibroblast-like cells that produce extracellular matrix proteins, are responsible for the desmoplasia in PDAC. Pancreatic stellate cells (PSCs) and fibroblasts (PFs) are key progenitors of CAFs. Blocking the expression and activity of CAFs may be a means to improve the therapy and prognosis of PDAC. This proposal posits that G-protein-coupled receptors (GPCRs) are an important, understudied aspect of pancreatic CAFs and may be novel targets for the treatment of pancreatic cancer. GPCRs are the largest family of cell surface signaling receptors (3% of the human genome) and regulate many physiological processes. As plasma membrane proteins, GPCRs are accessible from the extracellular space; GPCRs are selectively expressed on cell types and tissues and show specificity in ligand interaction-factors that help explain why GPCRs are the targets for ~30% of current therapeutic agents albeit not in oncology. This R21 seeks to be transformative by identifying, quantifying and validating the expression of GPCRs by human pancreatic CAFs, and by assessing the therapeutic potential of GPCRs selectively expressed by CAFs (compared to PSCs and PFs). The project uses patient-derived pancreatic CAFs as a model and will use several genomic strategies: a GPCRomic approach to quantify gene expression of all non-chemosensory GPCRs, use of RNA interference knockdown GPCRs expressed by CAFs and identify the GPCRs that mediate key functional responses and gain-of-function studies by using normal pancreatic fibroblasts or pancreatic stellate cells and seeking to recapitulate the fibrotic phenotype of CAFs by enhancing expression of GPCRs in PSCs and PFs. The goal is to use genomic approaches to identify GPCRs as potential targets for the treatment of pancreatic cancer through their ability to block expression and pro-fibrotic activity of CAFs. The strategy that we will employ- GPCRomics of members of the GPCR gene family and gain of function and loss of function studies with members of this family in a human disease (in this case, in pancreatic cancer-associated fibroblasts)-is a novel one that should be readily applicable to CAFs in other cancers and to other disease settings. In addition, a further novel and clinically important aspect of this proposl is its initiation of efforts to test the idea that GPCRs on CAFs (in particular pancreatic CAFs) may be druggable targets for a disease that is in desperate need of new therapies.