Expression and identification of recombinant P-selectin and P-selectin glycoprotein ligand-1 / 生理学报

P-selectin, one of the membrane proteins, expresses on platelet and endothelia and interacts with P-selectin glycoprotein ligand-1 (PSGL-1) on leukocyte membrane. This interaction mediates leukocytes rolling on endothelial membrane and then induces leukocyte recruitment to the site of infection or tissue injury. In the present study, we constructed the recombinant wild type human P-selectin, its calcium-binding sites mutants and recombinant PSGL-1-globulin (PSGL-1-Rg). They expressed in Sf9 cells by using the baculovirus expression system and were purified by TalonTM metal or Protein A affinity chromatography. The results showed that the recombinant PSGL-1-Rg interacted with recombinant wild type P-selectin and two P-selectin mutants with 2 calcium-binding sites mutation respectively, but could not bind to the P-selectin mutant with all 4 calcium-binding sites mutation. Therefore, we verified the importance of P-selectin calcium-binding sites for its interaction with PSGL-1.

Inhibition of bFGF gene expression and tumor angiogenesis of orthotopic implantation of human gastric carcinoma by N-desulfated heparin / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the effect of N-desulfated heparin on tumor metastasis, tumor angiogenesis and basic fibroblast growth factor(bFGF) gene expression of orthotopically implanted human gastric carcinoma in NOD-SCID mice.</p><p><b>METHODS</b>Human gastric cancer SGC-7901 tissues were orthotopically implanted into the stomach of the NOD-SCID mice. Twenty mice were randomly divided into two groups which received either intravenous injection of 0.9% NaCl solution(0.9%NaCl solution group) or 10 mg/kg N-desulfated heparin (N-desulfated heparin group) twice a week for three weeks. Mice were sacrificed six weeks after tumor implantation. Tissues from stomach and other organs were obtained for histopathological evaluation. The intratumoral microvessel density (MVD) in tumor was evaluated immunohistochemically. Real time PCR was used to detect bFGF mRNA expression.</p><p><b>RESULTS</b>The tumor metastasis rates were 9/10 in 0.9% NaCl solution group and 2/10 in N-desulfated heparin group(P<0.05).MVD was 9.1+/-3.4 in 0.9% NaCl solution group and 4.7+/-1.8 in N-desulfated heparin group (t=3.617,P<0.05). bFGF mRNA expression was lower in N-desulfated heparin group(2.60+/-0.56%)than that in 0.9% NaCl solution group(30.65+/-6.84%).</p><p><b>CONCLUSION</b>N-desulfated heparin can inhibit the metastasis of gastric cancer through inhibiting tumor bFGF gene expression and tumor angiogenesis with no obvious anticoagulant activity.</p>