The adaptor protein Shc integrates growth factor and ECM signaling during postnatal angiogenesis

Abstract

IntroductionAngiogenesis, the sprouting and growth of new blood vessels from preexisting vasculature, is critical for wound healing and in diseases such as rheumatoid arthritis, diabetes, and cancer. 1 Angiogenesis is a highly coordinated tissue-remodeling process activated by proangiogenic growth factors such as VEGF, the expression of which is up-regulated in hypoxic or cancer cells. VEGF receptors expressed on the endothelial cell (EC) surface become activated when bound to the VEGF ligand, initiating signaling cascades that lead to EC proliferation, migration, survival, and tube formation. 2 Basement membrane deposition and mechanical cues from the ECM transmitted via integrins also participate to coordinate vessel sprouting and remodeling in conjunction with the VEGF signaling pathway. 3 Given their transmembrane structure, ability to form associations with adaptor molecules, and ability to bind to extracellular ligands, VEGF receptors and integrins are well positioned to serve as functional hubs during the angiogenic process. 4 Adaptor proteins, which have no catalytic activity but instead promote protein-protein interactions, are important regulators of signaling pathways downstream of activated cell-surface receptors. 5 The prototypical adaptor protein Shc is an evolutionarily conserved, ubiquitously expressed protein that was originally described as an oncogene because of its participation in the activation of Ras and MAPKs downstream of a multitude of receptors for various growth factors, cytokines, and hormones. 6,7 Shc is expressed as 3 isoforms of 46, 52, and 66 kDa, all of which are products of the same gene, Shc1. 8,9 Global knockout of Shc1 in mice causes embryonic lethality at embryonic day 11.5. 10 These embryos exhibit severe defects in the cardiovascular system, including defective heart development and vessel remodeling. More detailed gene-targeting work has shown that the expression of the PTB domain of Shc specifically in cardiomyocytes is critical for midgestational heart development and embryonic life. 11 Conditional knockout strategies have shown that Shc is also important for the proper development/function of other organs such as skeletal muscle, 11 brain, 12 cardiomyocytes, 13 and thymocytes, 14 because tissue-specific deletion of Shc resulted in living but underdeveloped mice. To address the role of Shc in angiogenesis in vivo, we studied loss of Shc function using morpholino (MO) antisense technology in zebrafish. In addition, we used the Tie2-Cre transgene to generate mice null for Shc in ECs and some hematopoietic cells. 15 Surprisingly, these mice survived through development, enabling us to investigate the role of Shc in postnatal angiogenesis. We show herein that Shc is required for proper angiogenesis in vivo in both the zebrafish and mouse. Mechanistically, Shc is required for transmitting signals downstream of 2 major angiogenic signaling hubs, VEGFR-2 and integrins. Methods Zebrafish MO injectionTwo splice-blocking MOs targeting the zebrafish ortholog of Shc1 (accession nu...

The G Protein-Coupled Estrogen Receptor-1, GPER-1, Promotes Fibrillogenesis via a Shc-Dependent Pathway Resulting in Anchorage-Independent Growth

“…Further support for integrin α5β1 and Shc as an integration point in growth factor responsiveness and ECM signaling is demonstrated by the report that vascular endothelial cells coordinate FN-dependent adhesivity and vEGF receptor activation [66]. Similar to the work by Sweet and colleagues in vascular cells [66], we show that Shc is required for enhanced adhesion of breast cancer cells to FN-coated substrata, but not collagen (Fig. 3).…”

“…Our work presented here provides additional support for this idea by showing that GPER-1 mediates enhanced integrin α5β1-Shc-dependent adhesivity and further supports the concept that integrin α5β1 and Shc form a signaling node that regulates FN matrix assembly and the release of membrane-tethered HB-EGF by SKBR3 breast cancer cells [44]. Further support for integrin α5β1 and Shc as an integration point in growth factor responsiveness and ECM signaling is demonstrated by the report that vascular endothelial cells coordinate FN-dependent adhesivity and vEGF receptor activation [66]. Similar to the work by Sweet and colleagues in vascular cells [66], we show that Shc is required for enhanced adhesion of breast cancer cells to FN-coated substrata, but not collagen (Fig.…”

Targeting SHCBP1 Inhibits Cell Proliferation in Human Hepatocellular Carcinoma Cells

“…Shc SH2 domain serves an important function as a target point to tyrosine kinases receptor activation. Shc proteins can activate tyrosine kinases receptor via tyrosine phosphorylated (Tomilov et al, 2011;Tomilov et al, 2011;Sweet et al, 2012).The association of SHCBP1 with Shc via a novel phosphotyrosine independent interaction with the Shc SH2 domain. SHCBP1 was identified by its interaction with SHC, which is involved in FGF signaling (Schmandt et al 1999).…”

Cardiac contraction activates endocardial Notch signaling to modulate chamber maturation in zebrafish

“…MLECs were prepared as described previously (Sweet et al, 2012). MLECs at passage 38-45 were cultured on gelatin-coated plastic tissue culture plates and maintained in DMEM (Gibco, 11995), 10% fetal bovine serum (Sigma), 1% penicillin-streptomycin (Gibco), 1% non-essential amino acids (Gibco) and 0.009% β-mercaptoethanol.…”