An EMILIN1-Negative Microenvironment Promotes Tumor Cell Proliferation and Lymph Node Invasion

Abstract

The evidence that EMILIN1 (Elastic Microfibril Interface Located proteIN) deficiency in Emilin1 À/À mice caused dermal and epidermal hyperproliferation and an abnormal lymphatic phenotype prompted us to hypothesize the involvement of this extracellular matrix component in tumor development and in lymphatic metastasis. Using the 12-dimethylbenz(a)anthracene/12-O-tetradecanoylphorbol-13-acetate (DMBA/TPA) two-stage model of skin carcinogenesis, we found that Emilin1 À/À mice presented an accelerated formation, a higher incidence, and the development of a larger number of tumors compared with their wild-type littermates. EMILIN1-negative tumors showed more Ki67-positive proliferating cells and higher levels of pErk1/2. In these tumors, PTEN expression was lower. Emilin1 À/À mice displayed enhanced lymphangiogenesis both in the tumor and in the sentinel lymph nodes. Accordingly, tumor growth and lymph node metastasis of transplanted syngenic tumors were also increased in Emilin1 À/À mice. In vitro transmigration assays through lymphatic endothelial cells showed that EMILIN1 deficiency greatly facilitated tumor cell trafficking. Overall, these data established that EMILIN1 exerts a protective role in tumor growth, in tumor lymphatic vessel formation, as well as in metastatic spread to lymph nodes and reinforced the importance of its presence in the microenvironment to determine the tumor phenotype. Cancer Prev Res; 5(9); 1131-43. Ó2012 AACR.

TGF-β mediates early angiogenesis and latent fibrosis in an Emilin1-deficient mouse model of aortic valve disease

“…This results in elastases in the valve interstitium and migration of circulating hematopoietic (or non-resident) cells from either the newly formed valve neovasculature, which is not present until the aged stage, or the disrupted endothelium. There were areas of endothelial disruption around the edges of the Emilin1 −/− aortic valve (data not shown), which is consistent with previous findings (Zanetti et al, 2004; Danussi et al, 2012). Previous evidence suggests that activation of the phosphorylated Erk1/2 pathway is a crucial modifier in elastase-mediated diseases (Preston et al, 2002; Ghosh et al, 2012).…”

“…Constitutive phosphorylated Smad2/3 upregulation might result in early VIC activation, increased elastolytic activity, proliferation and provisional angiogenesis, whereas progressive phosphorylated Erk1/2 upregulation (or a cumulative threshold of both canonical and non-canonical TGF-β signaling) might result in late myofibroblast activation that results in fibrosis and inflammation, consistent with previous reports (Hutcheson et al, 2013). Previous reports have shown robust activation of phosphorylated Erk1/2 and proliferation in Emilin1 −/− fibroblast cells that is mediated through a PTEN-dependent pathway (Danussi et al, 2011; Danussi et al, 2012). However, in the current study, PTEN levels were unaltered despite Erk1/2 activation and increased proliferation in Emilin1 −/− valves, consistent with a role for activated non-canonical TGF-β signaling in aortic valve tissue.…”

“…Emilin1 (elastin microfibril interface-located protein) is an elastin- and fibulin-5-binding protein that is necessary for elastogenesis and inhibits transforming growth factor β (TGF-β) signaling (Zanetti et al, 2004; Zacchigna et al, 2006). In addition, fibroblasts, keratinocytes and lymphatic endothelial cells in Emilin1-deficient mice demonstrate increased proliferation due to absent Emilin1-integrin interactions (Danussi et al, 2011; Danussi et al, 2012). Importantly, Emilin1 is expressed in the developing and mature heart valves (Braghetta et al, 2002; Angel et al, 2011; Votteler et al, 2013), and Emilin1 deficiency results in EFF and TGF-β activation in the aorta.…”

EMILIN1/α9β1 Integrin Interaction Is Crucial in Lymphatic Valve Formation and Maintenance

“…Mouse lymphangioma endothelial cells (LAECs) were isolated following the procedure previously described (14). The cells were immortalized by means of simian virus 40 (SV40) infection (20).…”

Neutrophil elastase cleavage of the gC1q domain impairs the EMILIN1-α4β1 integrin interaction, cell adhesion and anti-proliferative activity

“…EMILIN1 is strongly expressed in the blood and lymphatic vessels and in the connective tissues of a wide variety of organs10111213. It is involved via the EMI domain in the maintenance of blood vascular cell morphology and function14; in addition, EMILIN1 promotes adhesion and migration1516 and controls cell proliferation1317 through its gC1q domain. So far, among the gC1q domains of several other ECM components, EMILIN1 gC1q is the only one capable of interacting with the α4β1 integrin15161718, which is predominantly expressed on the surface of hemopoietic cells, working as a receptor to allow adhesion to blood vessel wall19 or extracellular matrix constituents20.…”