Fibrosis-Protease Cross-Talk Regulating Pancreatic Cancer Invasion

描述（由申请人提供）：胰腺导管腺癌（Pancreatic ductal adenocarmicoma， PDAC）目前是美国癌症相关死亡的第四大原因，诊断后的中位生存期不到6个月，而5年无病生存期不到5%。较差的预后是由于在诊断时疾病阶段相对较晚，大约80%的患者表现为局部侵袭性或转移性疾病。PDAC与肿瘤周围强烈的纤维化反应有关，称为结缔组织增生反应。该反应由间质细胞外基质（ECM）组成，主要是I型胶原，以及增殖的成纤维细胞。然而，胰腺导管细胞、间质ECM和间质成纤维细胞之间的功能相互作用尚不清楚。根据NCI胰腺癌进展审查小组的说法，“需要更好地了解基质形成的基本机制，它与胰腺癌细胞的相互作用以及它在胰腺癌发病机制中的作用”。我们已经证明胰腺成纤维细胞沉积的细胞外基质促进TGF-？PDAC细胞中MT1-MMP的表达随之升高[Ottaviano等，Cancer Research, 2006]。我们的初步数据还表明，MT1-MMP增加cyclin D1表达，增强p38 MAPK信号，促进富胶原微环境中的生长。此外，我们的初步数据表明，使用转基因小鼠模型胰腺中MT1- MMP的表达会增加纤维化。综上所述，这些数据支持了我们的中心假设，即I型胶原、TGF-？1和MT1-MMP有助于PDAC的侵袭性表型：促结缔组织增生反应促进TGF-？1的表达和信号通路增加MT1-MMP的表达，但这反过来又导致纤维化扩大和TGF-？1信号和MT1-MMP的表达，从而增强PDAC的侵袭和转移。Aim 1中提出的实验旨在了解扩增环的前半部分(纤维化？TGF - ?1 ?MT1-MMP)通过阐明ECM，特别是I型胶原，增加TGF-？1和MT1-MMP在PDAC细胞中的表达。在目标2中，我们将检查扩增环的后半部分(MT1- MMP ？通过使用器官型、原位和转基因胰腺癌模型，阐明MT1-MMP在富含胶原的微环境中促进纤维化和促进胰腺肿瘤生长的机制。我们提出这些研究的基本原理是，一旦纤维化反应和PDAC细胞之间的串扰机制被完全确定，这些信息可能最终导致新的治疗策略，从而降低胰腺癌的发病率和死亡率。公共卫生相关性：胰腺导管腺癌（PDAC）的死亡率相对较高，主要是因为大约80%的患者在诊断时存在局部侵袭性或转移性疾病。PDAC通常与肿瘤周围富含胶原蛋白的强烈纤维化区（称为结缔组织增生反应）有关。虽然结缔组织增生反应可能是PDAC局部侵袭发展的重要前兆，也可能是转移的前兆，但促成这些过程的确切机制目前尚不清楚。本应用程序的目的是描述促纤维组织增生反应促进PDAC进展的分子机制，一旦纤维化反应和PDAC细胞之间的串扰机制被完全确定，我们预测这将导致新的治疗策略，从而降低胰腺癌的发病率和死亡率。

DESCRIPTION (provided by applicant): Pancreatic ductal adenocarcinoma (PDAC) is currently the fourth leading cause of cancer-related death in the U. S. The median survival time after diagnosis is less than 6 months, while 5-year disease-free survival is less than 5%. Poor outcome is attributed to the relatively advanced stage of disease at time of diagnosis, with approximately 80% of patients presenting with locally aggressive or metastatic disease. PDAC is associated with an intense fibrotic reaction around the tumor known as desmoplastic reaction. This reaction is composed of interstitial extracellular matrix (ECM), predominantly type I collagen, together with proliferating fibroblastic cells. However, the functional interactions among the pancreatic ductal cells, the interstitial ECM and the stromal fibroblasts are poorly understood. According to the NCI Pancreatic Cancer Progress Review Group 'a better understanding is needed of the basic mechanisms involved in the development of the stroma, its interaction with the pancreatic cancer cells and its role in the pathogenesis of pancreatic cancer'. We have demonstrated that extracellular matrix deposited by pancreatic fibroblasts promotes TGF-?1 expression by PDAC cells followed by increased MT1-MMP expression [Ottaviano AJ et al, Cancer Research 2006]. Our preliminary data also indicate that MT1-MMP increases cyclin D1 expression and enhances p38 MAPK signaling to promote growth in collagen-rich microenvironment. Moreover, our preliminary data suggest that expression of MT1- MMP in the pancreas using a transgenic mouse model increases fibrosis. Together these data support our central hypothesis that a feed-forward amplification loop involving cross-talk between type I collagen, TGF-?1 and MT1-MMP contributes to the aggressive phenotype of PDAC: the desmoplastic reaction promotes TGF-?1 expression and signaling to increase MT1-MMP expression, but this in turn contributes to expanded fibrosis and a further increase in TGF-?1 signaling and MT1-MMP expression, thus enhancing PDAC invasion and metastasis. Experiments proposed in Aim 1 have been designed to understand the first half of the amplification loop (fibrosis ? TGF-?1 ? MT1-MMP) by elucidating the mechanism by which the ECM, in particular type I collagen, increases TGF-?1 and MT1-MMP expression by PDAC cells. In Aim 2 we will examine the second half of the amplification loop (MT1- MMP ? fibrosis and growth in 3D collagen) by elucidating the mechanism by which MT1-MMP promotes fibrosis and facilitates pancreatic tumor growth in a collagen-rich microenvironment using organotypic, orthotopic and transgenic models of pancreatic cancer. Our rationale for these proposed studies is that once the mechanism of cross-talk between the fibrotic reaction and PDAC cells is fully determined, this information may ultimately lead to new treatment strategies that reduce the morbidity and mortality of pancreatic cancer. PUBLIC HEALTH RELEVANCE: The relatively high mortality resulting from pancreatic ductal adenocarcinoma (PDAC) is largely due to the fact that approximately 80% of patients present with locally invasive or metastatic disease at the time of diagnosis. PDAC is frequently associated with an intense area of collagen-rich fibrosis surrounding the tumor known as the desmoplastic reaction. While the desmoplastic reaction is likely an important precursor to the development of PDAC local invasion, and perhaps metastases as well, the precise mechanisms that contribute to these processes are currently not well understood. The objective of this application is to delineate the molecular mechanisms by which desmoplastic reaction contributes to PDAC progression, and once the mechanism of cross-talk between the fibrotic reaction and PDAC cells is fully determined, we predict that this will lead to new treatment strategies that reduce the morbidity and mortality of pancreatic cancer.