Use of antifibronectin agents to target fibrosis in mammary cancer

描述（由申请人提供）：摘要致密乳腺组织产生肿瘤的可能性是非致密组织的4-5倍，使得高达三分之一的所有乳腺癌起源于乳房X线摄影致密组织。乳腺密度增加是由于细胞外基质（ECM）成分，特别是胶原蛋白和纤连蛋白（FN）沉积的显著增加。最近在小鼠模型中的研究表明，增加的胶原密度促进乳腺肿瘤的形成和进展。FN是一种血清和细胞外基质糖蛋白，其沉积到纤维状结构中先于并控制所研究的各种系统中的胶原纤维形成。纤维连接蛋白的沉积，并通过募集产生促纤维化细胞因子的免疫和炎性细胞来促进炎症和纤维化。纤连蛋白也是新血管形成的关键组分，新血管形成是肿瘤生长的重要组分。与可以自组装的胶原相反，FN原纤维形成受到细胞表面分子的严格控制。我们假设FN组装可能是一种 药物靶点，并可能创造机会，以调节随后的胶原蛋白沉积。我们假设FN基质组装的抑制剂将减少乳腺癌进展过程中观察到的纤维化，并将减少肿瘤进展。我们的目标是确定FN组装的小分子抑制剂，其可用作治疗剂以降低乳腺癌的发病率、致瘤性和/或转移。将测试两种类型的抑制剂。第一种类型的抑制剂是来自化脓性链球菌的肽，称为FUD的功能性上游结构域，我们已经广泛表征为FN组装的有效和特异性抑制剂。其他人已经在心血管重塑的小鼠模型中使用FUD，其中它抑制FN和胶原蛋白组装、白细胞浸润和损伤部位的炎症。第二种类型的抑制剂是通过使用我们开发的FN组装测定的中试高通量筛选鉴定的小分子。我们选择了三种由此产生的抑制剂在乳腺癌的胶原密集小鼠模型中进行测试，并建议表征和测试在Broad Institute（剑桥，MA）进行的更大筛选产生的新型抑制剂。提出了两个具体目的：1）确定FN沉积是否影响小鼠中胶原致密乳腺癌的致瘤性; 2）鉴定和表征来自Broad Institute高通量筛选的破坏FN纤维形成的新小分子，以确定其在小鼠乳腺癌模型中阻断纤维化和肿瘤进展的功效。所提出的工作是新颖的和重要的，因为即使已经确定胶原蛋白排列和纤维化伴随肿瘤进展，但胶原蛋白和细胞外基质沉积的控制在肿瘤治疗中尚未被确定为“可药物化的”。我们的团队结合了胶原致密乳腺癌动物模型所需的专业知识，获得小分子筛选和最先进的活体成像技术，以确定可能开发成乳腺癌治疗药物的相关探针。

DESCRIPTION (provided by applicant): Abstract Dense mammary tissues are 4-5 times more likely to generate tumors than non-dense tissues, such that up to a third of all breast cancers originate in mammographically dense tissue. Increased breast density arises from a significant increase in deposition of extracellular matrix (ECM) constituents, in particular, collagen and fibronectin (FN). Recent studies in murine models have shown that increased collagen density promotes mammary tumor formation and progression. FN is a serum and extracellular matrix glycoprotein whose deposition into fibrillar structures precedes and controls collagen fibril formation in a variety of systems studied. Deposition of fibronectin and contributes to inflammation and fibrosis by recruitment of immune and inflammatory cells that produce pro-fibrotic cytokines. Fibronectin is also a critical component of neo- vascularization, an important component in tumor growth. In contrast to collagen, which can self-assemble, FN fibrillogenesis is tightly controlled by molecules at cell surfaces. We postulate that FN assembly is potentially a drug target and may create an opportunity to regulate subsequent collagen deposition. We hypothesize that inhibitors of FN matrix assembly will diminish fibrosis observed during breast carcinoma progression, and will decrease tumor progression. Our objective is to identify small molecule inhibitors of FN assembly that may be utilized as therapeutics to decrease breast carcinoma incidence, tumorigenicity, and/or metastasis. Two types of inhibitors will be tested. The first type of inhibitor is a peptide derived from Streptococcus pyogenes, termed FUD for Functional Upstream Domain, which we have characterized extensively as a potent and specific inhibitor of FN assembly. Others have utilized FUD in a murine model of cardiovascular remodeling where it inhibited FN and collagen assembly, leukocyte infiltration and inflammation at the injured site. The second type of inhibitors are small molecules identified through a pilot high throughput screen using a FN assembly assay we developed. We chose three of the resulting inhibitors to test in collagen-dense murine models of mammary carcinoma and propose to characterize and test novel inhibitors resulting from a larger screen to take place at the Broad Institute (Cambridge, MA). Two Specific Aims are proposed: 1) Determine if FN deposition affects tumorigenicity of collagen-dense breast carcinomas in mice; 2) Identify and characterize new small molecules that disrupt FN fibrillogenesis derived from High Throughput Screening at the Broad Institute for their efficacy in blocking fibrosis and tumor progression in mouse mammary carcinoma models. The proposed work is novel and significant in that, even though it is well established that collagen alignment and fibrosis accompany tumor progression, the control of collagen and extracellular matrix deposition has not been identified as "druggable" in the treatment of tumors. Our group combines the needed expertise in collagen dense mammary carcinoma animal models, access to small molecule screening, and state-of-the art intravital imaging technology to identify relevant probes to be potentially developed into therapeutics against breast cancer.