The deposition of extracellular matrix (ECM) is a defining feature of pancreatic ductal adenocarcinoma (PDA), where ECM signaling can promote cancer cell survival and epithelial plasticity programs. However, ECM signaling can also limit PDA tumor growth by producing cytotoxic levels of reactive oxygen species. For example, excess fibronectin stimulation of ␣5␤1 integrin on stromal cells in PDA results in reduced angiogenesis and increased tumor cell apoptosis because of oxidative stress. Fibulin-5 (Fbln5) is a matricellular protein that blocks fibronectin-integrin interaction and thus directly limits ECMdriven reactive oxygen species production and supports PDA progression. Compared with normal pancreatic tissue, Fbln5 is expressed abundantly in the stroma of PDA; however, the mechanisms underlying the stimulation of Fbln5 expression in PDA are undefined. Using in vitro and in vivo approaches, we report that hypoxia triggers Fbln5 expression in a TGF-␤-and PI3K-dependent manner. Pharmacologic inhibition of TGF-␤ receptor, PI3K, or protein kinase B (AKT) was found to block hypoxia-induced Fbln5 expression in mouse embryonic fibroblasts and 3T3 fibroblasts. Moreover, tumor-associated fibroblasts from mouse PDA were also responsive to TGF-␤ receptor and PI3K/AKT inhibition with regard to suppression of Fbln5. In genetically engineered mouse models of PDA, therapy-induced hypoxia elevated Fbln5 expression, whereas pharmacologic inhibition of TGF-␤ signaling reduced Fbln5 expression. These findings offer insight into the signaling axis that induces Fbln5 expression in PDA and a potential strategy to block its production.The maintenance of solid tumors relies heavily on cues received from the surrounding environment. The ECM 2 is composed of structural proteins such as FN and collagen, which promote signaling through integrins and receptor tyrosine kinases (1, 2). ECM signaling is modulated by matricellular proteins, which regulate ECM-cell interactions without serving a direct structural function (3-5). The composition of the ECM is dynamic and varies between tumors and tumor types, contributing to intra-and intertumor heterogeneity, which presents challenges for effective therapeutic strategies. Furthermore, mouse studies have revealed anti-and pro-tumorigenic functions for ECM (5-7). In addition to ECM, stromal cells, including endothelial cells, immune cells, and fibroblasts, are present in the tumor microenvironment. These cells contribute to tumor growth, invasion, and chemoresponse (8 -10).During tumor progression, cancer cells release factors that maintain a microenvironment conducive for growth. For example, TGF-␤ is a cytokine expressed in many cancers that enhances the expression of multiple ECM molecules, including but not limited to FN, collagen, elastin, and fibulins (11-13). Fbln5 is a 448-amino acid secretory glycoprotein of the fibulin family of matricellular proteins. Fbln5 is unique among its members as it contains an RGD-integrin binding domain and can ligate a number of integrins (14). Fbln5 is ex...

Animal treatment can benefit from advances made in human health care, yet the technology can be cost prohibitive. This article discusses a sampling of high–tech wound dressings that can be used in veterinary practice. It also presents the simple and effective methodology for obtaining free medical supplies from acute care facilities.

Elevated levels of TGF-β are a negative prognostic indicator for patients diagnosed with pancreatic cancer; as a result the TGF-β pathway is an attractive target for therapy. However, clinical application of pharmacologic inhibition of TGF-β remains challenging because TGF-β has tumor suppressor functions in many epithelial malignancies including pancreatic cancer. In fact, direct neutralization of TGF-β promotes tumor progression of genetic murine models of pancreatic cancer. Here we report that neutralizing the activity of murine TGF-β receptor 2 using a monoclonal antibody (2G8) has potent anti-metastatic activity in orthotopic human tumor xenografts, syngenic tumors and a genetic model of pancreatic cancer. 2G8 induced an anti-metastatic stromal phenotype by increasing pro-inflammatory macrophages and NK cells and concomitantly decreasing anti-inflammatory macrophages, MDSCs and activated fibroblasts. These stromal specific changes resulted in tumor cell epithelial differentiation and a potent reduction in metastases. We conclude that TGF-β signaling within stromal cells participates directly in tumor cell phenotype and pancreatic cancer progression. Thus, strategies that inhibit TGF-β dependent effector functions of stromal cells could be efficacious for the therapy of pancreatic tumors. This abstract is also presented as Poster A38. Citation Format: Katherine T. Ostapoff, Bercin Kutluk Cenik, Miao Wang, Risheng Ye, Xiaohing Xu, Desiree Nugent, Michelle Hagopian, Mary Topalovski, Lee B. Rivera, Kyla D. Carroll, Rolf A. Brekken. Neutralizing the activity of murine TGF-β receptor 2 promotes a differentiated tumor cell phenotype and inhibits pancreatic cancer metastasis. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr PR07. doi:10.1158/1538-7445.CHTME14-PR07