CD44 enhances the epithelial-mesenchymal transition in association with colon cancer invasion

Abstract

Abstract. The metastatic process involves the migration and invasion of cancer cells throughout the body to produce secondary tumors at distant sites. Through of epithelial-mesenchymal transition (EMT), cancer cells employ developmental processes to gain migratory and invasive properties. CD44 is the transmembrane adhesion receptor for Hyaluronan (HA) and plays a central role in the remodeling and degradation of HA that leads to cell migration, as well as to cancer invasion and metastasis. CD44 is highly expressed in primary and metastatic colon cancer but lowly expressed in normal tissues. We evaluated the impact of CD44 on EMT and invasion of colon cancer cells. The functional role of CD44 in EMT was determined by the overexpression or knockdown of CD44. CD44 was overexpressed by transfection with plasmid-RT-PCR product and knockdown of CD44 by small hairpin RNA (shRNA)-mediated depletion of CD44 in SW480 colon cancer cells. Morphological changes were evaluated by confocal laser microscopy in the culture media. The expression of EMT markers (E-cadherin/N-cadherin/vimentin/fibronectin/actin/ MMPs) and CD44/EGFR/PI3K-Akt signaling were evaluated using western blotting. The influence of EMT in tumor biology was assessed with proliferation, migration and invasion assays. EMT changes increased in CD44-overexpressing SW480 cells and decreased in CD44 knockdown cells. CD44 activation induced expression of EGFR and activation of phosphatidylinositol 3' kinase (PI3K)/Akt and expression of glycogen synthase kinase-3 β (GSK-3β). In terms of EMT markers, CD44 downregulated E-cadherin expression, upregulated N-cadherin, α-actin, vimentin, fibronectin and MT1-MMP, and inhibited the formation of the membrane-associated E-cadherin-β-catenin complex, which resulted in cell invasion and migration.

TiHo-0906: a new feline mammary cancer cell line with molecular, morphological, and immunocytological characteristics of epithelial to mesenchymal transition

“…HMGA2 elicits EMT by activating a series of transcription factors 24,25 , while CD44 participates in the downregulation of E-cad commonly observed during EMT 12,28 . Immunohistochemically, there were no specific cross-reactivity of the HMGA2 selected antibody with feline tissue.…”

“…Therefore, EMT-derived cells are usually characterized by a higher HMGA2 expression 9,26 , loss or reduced expression of E-cadherin (E-cad), up-regulation of vimentin (Vim) 7,9 , and co-expression of epithelial markers (cytokeratins [CKs]) and mesenchymal markers (calponin [CALP], smooth muscle actin [SMA], and Vim) 7,27 . Other markers like CD44 participate in the downregulation of E-cad 12,28 . Consequently, EMT-derived cells are characterized by a higher CD44 expression 8,28 .…”

“…Other markers like CD44 participate in the downregulation of E-cad 12,28 . Consequently, EMT-derived cells are characterized by a higher CD44 expression 8,28 . The overexpression of this cell surface protein leads to enhanced cell migration, cancer invasion and metastasis 28 .…”

“…Consequently, EMT-derived cells are characterized by a higher CD44 expression 8,28 . The overexpression of this cell surface protein leads to enhanced cell migration, cancer invasion and metastasis 28 . Additionally, a higher CD44 expression in combination with other surface markers is used for CSCs identification 29,30 .…”

Hyaluronan Regulation of Endothelial Barrier Function in Cancer

“…We have reported that HMW-HA enhances EC barrier function (Singleton et al, 2006, 2010). The HA in the stroma of several cancers has been implicated in numerous processes including inhibition of apoptosis, stimulation of tumor cell proliferation, migration and invasion, epithelial mesenchymal transition, protection from immune cells, and regulation of intercellular space (Auvinen et al, 2013; Bollyky et al, 2009; Cho et al, 2012; Dickinson & Gerecht, 2010; Sironen et al, 2011; Tammi et al, 2008). Whether this stroma-associated HA also promotes resealing of new capillaries remains to be determined.…”