Hepatocyte growth factor differently influences Met-E-cadherin phosphorylation and downstream signaling pathway in two models of breast cells

Abstract

E-cadherins are implicated in cell adhesion, and also in cell signaling by associating with tyrosine kinase-receptors such as Met, the hepatocyte growth factor (HGF) receptor. Using two different cellular models, i.e. MCF-7 (breast carcinoma) and MCF-10 (immortalized mammary) cells, we studied the possible mechanism(s) by which E-cadherins modulate the signaling pathways downstream of Met, leading to beta-catenin-TCF transcriptional activity. In MCF-7, but not in MCF-10 cells, E-cadherins were remarkably associated with Met. Moreover, in MCF-7 cells both co-immunoprecipitation with anti-Met antibody and co-localization were increased by 30-min HGF treatment, which caused E-cadherin tyrosine phosphorylation. Also beta-catenin in the co-immunoprecipitate was phosphorylated by HGF, probably favoring TCF activation. Consistently, after HGF treatment, beta-catenin redistributed earlier in MCF-7 than in MCF-10 cells, with nuclear accumulation and activation of TOPFLASH gene reporter. Our results indicate a functional role of Met-E-cadherin interaction in MCF-7 cells through the amplification of the signaling downstream of HGF-Met triggering that involved c-Src and phosphoinositide-3-kinase activities.

PIPKIγi5 regulates the endosomal trafficking and degradation of E-cadherin

“…HGF is known to induce Src activation and E-cadherin endocytosis, ubiquitylation and degradation, leading to the characteristic depolarization and scattering of epithelial cells that is indicative of EMT (Cutrupi et al, 2000;Fujita et al, 2002;Giehl and Menke, 2008;Guarino et al, 2007;Matteucci et al, 2006;Palacios et al, 2005;Shelly and Herrera, 2002;Shen et al, 2008). Our data indicate that Y646 and Y649 in PIPKIci5 are crucial for regulating its association with SNX5.…”

c-Src/Histone Deacetylase 3 Interaction Is Crucial for Hepatocyte Growth Factor–Dependent Decrease of CXCR4 Expression in Highly Invasive Breast Tumor Cells

“…The perinuclear compartment includes the late endosomes/lysosomes, i.e., the major route for Met degradation after proteasome delivery, as well as the Golgi, corresponding to a recycling compartment or containing newly synthesized Met (41). A functional significance for internalized Met might be suggested in the regulation of signal transduction pathways and nuclear gene expression, as reported in MCF-7 cells by us and other authors under different experimental conditions (3,42).…”

“…Our data show that in breast neoplastic cells (MCF7) but not in normal epithelial cells (MCF-10), Met and E-cadherins coimmunoprecipitate and undergo coendocytosis after hepatocyte growth factor (HGF) treatment (3). The multifunctional cytokine HGF is the ligand for Met, and an increased autocrine HGF-Met signaling is a critical downstream function of c-Src -Stat3 pathway in mammalian tumorigenesis (5).…”

“…MCF-7 and MDA-MB231 cells (4 Â 10 4 ) were seeded on sterile coverslips, previously placed in 24-multiwell plates, and were allowed to attach (3). The cells were transfected at 70% to 80% of confluence with Srcwt expression vector or were starved and treated with HGF for 30 or 60 min.…”

“…Spatial and temporal control of the signals emanating from tyrosine kinase receptor Met depends on the diverse repertoire of recruited proximal signaling proteins (1) and is modulated by the partner proteins integrins and E-cadherins, differently expressed on the surface of normal and neoplastic cells in relation to their aggressiveness (2)(3)(4). Our data show that in breast neoplastic cells (MCF7) but not in normal epithelial cells (MCF-10), Met and E-cadherins coimmunoprecipitate and undergo coendocytosis after hepatocyte growth factor (HGF) treatment (3).…”