Involvement Of E-selectin Research Articles

E-selectin: Its Role in Cancer and Potential as a Biomarker

The involvement of E-selectin in cancer has long been recognized based on histopathological studies, and the important role of E-selectin in cancer progression and metastasis was further reinforced by a number of basic researches. Both the solid state and soluble forms of E-selectin have been tested as a possible biomarker for different cancer types for detection as well as for monitoring. While a number of studies have suggested the potential usefulness of E-selectin as a biomarker, the results from clinical trials are somewhat controversial and it has not been translated into clinical utility. It appears that the use of E-selectin as a single biomarker for diagnosis and prognosis may require more careful evaluation. The utility of E-selectin as a biomarker in conjunction with other biomarkers that are relevant to the biological cascade for E-selectin or are critical for patient prognosis may open up a new venue to further establish E-selectin as a cancer biomarker.

Involvement of E-selectin in recruitment of endothelial progenitor cells and angiogenesis in ischemic muscle

AbstractE-selectin plays critical roles in tethering leukocytes to endothelial cells (ECs). We studied the role of E-selectin in endothelial progenitor cell (EPC) homing and vasculogenesis. After ischemia, the expression of E-selectin on ECs peaked 6 to 12 hours and returned to baseline at 24 hours, whereas the level of soluble E-selectin (sE-selectin) in serum increased over 24 hours and remained high at day 7. Mouse bone marrow–derived EPCs expressed not only E-selectin but also its ligand. Homing of circulating EPCs to ischemic limb was significantly impaired in E-selectin knock-out mice, as well as wild-type mice pretreated with blocking antibody against E-selectin, which was rescued by local sE-selectin injection. Mechanism for this is that sE-selectin stimulated not only ECs to express ICAM-1, but also EPCs to secrete interleukin-8 (IL-8), leading to enhanced migration and incorporation to ECs capillary formation. In therapeutic aspect, local treatment with sE-selectin enhanced efficacy of EPC transplantation for vasculogenesis and salvage of ischemic limb. Conversely, when E-selectin was knocked down by E-selectin small interfering RNA, blood flow recovery after EPC transplantation was significantly impaired. But this impaired vasculogenesis was rescued by sE-selectin. In conclusion, these data demonstrate E-selectin is a pivotal molecule for EPCs' homing to ischemic limb and vasculogenesis.

Especially Polymorphonuclear Leukocytes, but also Monomorphonuclear Leukocytes, Roll Spontaneously in Venules of Intact Rat Skin: Involvement of E-Selectin

White blood cells roll spontaneously in venules of intact, noninflamed rat skin. We investigated noninvasively in two experimental series which leukocyte subtypes participate in this phenomenon and the possible involvement of E-selectin. Male Lewis rats were anesthetized with sodium pentobarbital, and intravital video microscopy was performed on postcapillary venules in the nail-fold of a hind leg. In series 1 acridine yellow was infused for 15 min (50 mg per kg intravenously) to stain the leukocyte nuclei in situ. With the use of fluorescence microscopy rolling leukocytes could be classified unequivocally as polymorphonuclear (granulocytes) or monomorphonuclear (lymphocytes/monocytes) by the shape of their nucleus. Irrespective of vessel depth beneath the skin surface (25-45 microm), most identified rolling leukocytes were classified as granulocytes (72%-100%; median 89%). This percentage was independent of total rolling leukocyte flux, systemic leukocyte count, or their in vitro differentiation pattern. In series 2, rats were treated with either a synthetic, highly selective E-selectin blocking peptide or a control peptide (intravenously, 12 mg peptide per kg bolus, followed by 50 mg per kg per h). E-selectin blockade significantly reduced the leukocyte rolling level to about 50% of baseline (p <0.01), whereas the rolling velocity increased (p <0.01); the control peptide had no effect. In summary, most of the leukocytes rolling spontaneously in postcapillary venules of intact rat skin are granulocytes, despite the absence of an acute inflammatory reaction. One of the adhesion molecules involved in this phenomenon is E-selectin.

Adhesion Molecule Expression and Endothelial Cell Activation in Cutaneous Leukocytoclastic Vasculitis

To investigate the sequential expression of adhesion molecules on endothelium and inflammatory cells in cutaneous leukocytoclastic vasculitis, and the relation of these adhesive molecules with clinical and histologic variables. An immunohistochemical analysis (streptavidin-biotin-peroxidase technique) of 42 vasculitic lesions of up to 96 hours was performed using a panel of monoclonal antibodies specific for different adhesion molecules. Twenty normal skin samples and 3 perilesional specimens served as control samples. A clinical protocol was also performed, and patients were followed up for 1 to 5 years. A clinicopathologic research unit of a university hospital. Forty-two patients, 21 women and 21 men, aged 22 to 79 years, with cutaneous leukocytoclastic vasculitis. Three skin biopsy specimens of vasculitic lesions from each patient were obtained for histopathologic examination on paraffin, direct immunofluorescence, and immunohistochemical analysis on cryostatic tissue sections. The histologic characteristics and the immunohistochemical-stained specimens were evaluated by 3 independent investigators, using a semiquantitative method. Increased endothelial expression of very late activation antigen-1, HLA-DR, and intercellular adhesion molecule-1 was observed. The induction of E-selectin expression was more marked in recent lesions (P < .001) and correlated with the proportion of infiltrating neutrophils (P = .03). Endothelial expression of vascular cell adhesion molecule-1 was restricted to developed lesions. Most infiltrating cells were neutrophils expressing Mac-1. In 1 patient, lymphocyte function associated antigen-1 expression was also up-regulated. No significant increase in CD3, CD8, or CD71 immunoreactivity was found. An up-regulation of perivascular cells expressing HLA-DR and vascular cell adhesion molecule-1 was observed in vasculitic lesions. This cellular staining correlated with long-term evolution of the disease (P = .04). Adhesion molecules are sequentially upregulated in cutaneous leukocytoclastic vasculitis. The results of this study support the possible involvement of E-selectin in mediating recruitment of neutrophils expressing Mac-1.

Tumor necrosis factor induces E-selectin production in splanchnic artery occlusion shock

Splanchnic arteries were clamped for 45 min to induce splanchnic artery occlusion (SAO) shock in anesthetized rats. Sham-operated animals were used as controls. Survival time, serum tumor necrosis factor-alpha (TNF-alpha), white blood cell (WBC) count, mean arterial blood pressure, myeloperoxidase (MPO) activity, and serum levels of soluble E-selectin (sE-selectin) were investigated. SAO-shocked rats exhibited decreased survival time (95 +/- 11 min, whereas sham-shocked rats survived for > 5 h), reduced mean arterial blood pressure, increased serum levels of TNF-alpha (185 +/- 8 U/ml) and MPO activity in the ileum (0.11 +/- 0.03 U x 10(-3)/g tissue) and lung (1.5 +/- 0.4 U x 10(-3)/g tissue), leukopenia, and enhanced serum levels of sE-selectin. Furthermore SAO-shocked rats showed histological alterations in the ileum and lung. Administration of cloricromene (2 mg/kg i.v.), an inhibitor of TNF-alpha, significantly increased survival time (225 +/- 10 min), decreased serum levels of TNF-alpha and sE-selectin, reduced leukopenia and MPO activity in the ileum (0.035 +/- 0.003 U x 10(-3)/g tissue) and lung (0.3 +/- 0.005 U x 10(-3)/g tissue), improved the cardiovascular changes, and reduced the histological changes in the ileum and lung. Finally, an anti-E-selectin antibody protected rats against SAO shock. Our findings are consistent with an involvement of E-selectin, "in vivo," in the pathogenesis of SAO shock.

CD36 Induction on Human Monocytes upon Adhesion to Tumor Necrosis Factor-activated Endothelial Cells

Cell adhesion between circulating monocytes and the endothelium is a critical component of vascular thromboregulation and atherogenesis. The biochemical and genetic consequences of adhesion are poorly understood. We have found that monocyte surface expression of CD36, an integral membrane receptor for thrombospondin, collagen, and oxidized low density lipoprotein, increased dramatically upon adhesion to tumor necrosis factor-activated human umbilical vein endothelial cells (HUVEC). Expression was assessed by indirect immunofluorescence microscopy and immunoblotting using monoclonal antibodies to CD36. Steady-state CD36 mRNA levels, detected by RNase protection assay, also showed a similar pattern of up-regulation. To verify the adhesion dependence of the observed phenomenon, monocytes were co-cultured with tumor necrosis factor-activated HUVEC in a transwell apparatus that physically separated monocytes from the endothelial cells. Under these conditions, no increase in CD36 expression was detected, demonstrating that the enhanced monocyte CD36 expression observed is not due to soluble factors released by HUVEC. To characterize the specific adhesion molecules involved in the process, co-culture assays were performed on murine L cells transfected with either human E-selectin or intercellular adhesion molecule-1 cDNAs. A dramatic increase in CD36 mRNA was seen upon monocyte adhesion to E-selectin-transfected L cells compared with adhesion to intercellular adhesion molecule-1 or control transfectants. Furthermore, monoclonal antibodies to E-selectin inhibited the adhesion-dependent up-regulation of CD36 mRNA induced by transfected L cells or cytokine-activated endothelial cells. These findings demonstrate adhesion-dependent gene regulation of monocyte CD36 and suggest the possible involvement of E-selectin in initiating this process.