Cell-surface nucleolin is a signal transducing P-selectin binding protein for human colon carcinoma cells

Abstract

We have previously shown that P-selectin binding to Colo-320 human colon carcinoma cells induces specific activation of the α 5 β 1 integrin with a concomitant increase of cell adhesion and spreading on fibronectin substrates in a phosphatidylinositol 3-kinase (PI 3-K) and p38 MAPK-dependent manner. Here, we identified by affinity chromatography and characterized nucleolin as a P-selectin receptor on Colo-320 cells. Nucleolin mAb D3 significantly decreases the Colo-320 cell adhesion to immobilized P-selectin-IgG-Fc. Moreover, nucleolin becomes clustered at the external side of the plasma membrane of living, intact cells when bound to cross-linked P-selectin-IgG-Fc chimeric protein. We have also found P-selectin binding to Colo-320 cells induces tyrosine phosphorylation specifically of cell-surface nucleolin and formation of a signaling complex containing cell surface nucleolin, PI 3-K, and p38 MAPK. Using siRNA approaches, we have found that both P-selectin binding to Colo-320 cells and formation of the P-selectin-mediated p38 MAPK/ PI 3-K signaling complex require nucleolin expression. These results show that nucleolin (or a nucleolin-like protein) is a signaling receptor for P-selectin on Colo-320 cells and suggest a mechanism for linkage of nucleolin to P-selectin-induced signal transduction pathways that regulate the adhesion and the spreading of Colo-320 on fibronectin substrates.

Interplay between αvβ3 Integrin and Nucleolin Regulates Human Endothelial and Glioma Cell Migration

“…The latter has important roles in cell migration (41) and the remodeling of actin filaments induced by growth factors (42) and integrins (43), and is involved in PTN-induced endothelial cell migration (26). Both the regulation of nucleocytoplasmic shuttling of NCL by phosphorylation (44) and the reported physical interaction between NCL and PI3K (16,45), indicates a possible direct regulation of NCL by PI3K upon ␤ 3 Tyr 773 phosphorylation. Alternatively, PI3K may drive NCL membrane shuttling through regulation of other targets that interact with NCL.…”

“…Moreover, it binds a variety of ligands that play critical roles in tumorigenesis and angiogenesis, such as hepatocyte growth factor (13), endostatin (14), tumor homing peptide F3 (6), laminin (15), P-selectin (16), and midkine (17). We have recently shown that NCL interacts with the heparin-binding growth factor pleiotrophin (PTN) in both chorioallantoic membrane vessels and human endothelial cells.…”

RNA-binding protein nucleolin in disease

“…86,87 Cell-surface nucleolin also mediated signaling events such as calcium entry and calcium-regulated pathways, lipopolysaccharide-stimulated expression and secretion of TNFα and IL-1β and P-selectin-induced pathways that regulate cell adhesion and spreading. [88][89][90] Nucleolin was found to be the receptor of endostatin and peptides F3 and N6L. [91][92][93] Besides tumorigenesis, angiogenesis and signaling pathways, cell-surface nucleolin also participates in viral and bacterial infection.…”

Human anti-nucleolin recombinant immunoagent for cancer therapy

“…Altered NCL expression and localization results in oncogenic effects, such as stabilization of AKT, Bcl-2, Bcl-XL, and IL-2 mRNAs (9-11). Moreover, surface-NCL acts as a receptor for several oncogenic ligands (12)(13)(14)(15) and viruses (16). Recently, we reported that NCL has a critical protumorigenic function regulating the biogenesis of selected microRNAs (miRNAs), a class of noncoding single-stranded RNAs 19-22 nt in length (17) that regulate gene expression at the posttranscriptional level by targeting mRNAs in a sequence-specific manner (18).…”