In order to generate a pharmacophore model of integrin alphavbeta3 receptor antagonists and design lead compounds which have potent and selective activity against alphavbeta3 receptor with the help of this model. Thirty compounds (four categories) with highly inhibitory activity against the integrin alphavbeta3 receptor (IC50 < 110 nmol x L(-1)), amide, piperazine, piperidine, gamma-valerolactam as the intermediate junction, separately, were selected as a training set to construct a three-dimensional pharmacophore models of integrin alphavbeta3 receptor antagonists with the Catalyst software. The best pharmacophore model of integrin alphavbeta3 receptor antagonists with RMS = 0.73, Correl = 0.90, Weight = 1.17, Config = 14.00 is found out, which consisting of four features: a neg ionizable core (NI), two aliphatic hydrophobic core (HP) and an aromatic ring center (RA). Some new and easily obtained compounds with fine ADME properties and highly potent activity against alphavbeta3 receptor were designed with the new pharmacophore models.
Computer-Aided Design ; Drug Design ; Integrin alphaVbeta3 ; antagonists & inhibitors ; chemistry ; Models, Molecular ; Molecular Structure

Acetates ; chemistry ; Aminopyridines ; chemistry ; Angiogenesis Inhibitors ; chemistry ; Benzodiazepinones ; chemistry ; Humans ; Integrin alphaVbeta3 ; antagonists & inhibitors ; chemistry ; Ligands ; Molecular Structure ; Oligopeptides ; chemistry ; Peptides, Cyclic ; chemistry

OBJECTIVETo explore the design and activity determination of small molecular inhibitors of integrin alphavbeta3 through structure-based virtual screening.

METHODSBased on the crystal structure of integrin ctv33 extracellular segment in complex with an ARG-GLY-ASP ligand, docking procedure against the receptor binding domain was performed on 3D database. Integrin alphavbeta3-mediated cell adhesion assay was performed to assess the adhesion-inhibiting ability of the candidate compounds. Cell migration assay and capillary-structure-like formation inhibition assay were used to estimate the effects of the compounds on integrin alphavbeta3. Analysis of molecular graphics was carried out to deduce a probable binding model of compound with integrin alphavbeta3.

RESULTSFrom the top 1000 compounds with the best DOCK energy score, 50 compounds were selected for biological assay based on chemical and drug-like diversity. Seven of 50 compounds showed notable inhibition activity on cell adhesion, and two with half-maximum inhibition concentration (IC50) values less than 100 mol/L. The compound with best activity (1-37) showed high inhibitory activity in cell migration assay and capillary-structure-like formation inhibition assay. Molecular graphics analysis indicated that metal ion-dependent adhesion site (MIDAS) might be involved in the compound 1-37-mediated inhibition of ligand binding with integrin alphavbeta3.

CONCLUSIONSThrough virtual screening combined with biological assay, a promising lead compound was discovered to inhibit integrin alphavbeta3, which embodies the rational drug design with computation aid and brings a new thought and approach to find novel inhibitors of integrin.

Cell Adhesion ; drug effects ; Cell Movement ; drug effects ; Cells, Cultured ; Endothelial Cells ; drug effects ; physiology ; High-Throughput Screening Assays ; Humans ; Integrin alphaVbeta3 ; antagonists & inhibitors ; chemistry ; Neovascularization, Physiologic ; drug effects ; Quantitative Structure-Activity Relationship ; Umbilical Veins ; cytology

Integrins such as αvβ3, α5β1 play a key role in angiogenesis regulation, invasion and metastasis, inflammation, wound healing, etc. The up-regulation of integrin αvβ3 after cerebral ischemic stroke can promote angiogenesis, which in turn improves functional recovery. In addition, the integrin αvβ3 inhibitor can block the blood-brain barrier (BBB) leakage induced by vascular endothelial growth factor (VEGF) and also can reduce inflammatory reaction, decrease the deposition of fibrinogen. Other studies showed that integrin αvβ3 is not essential in revascularization. Therefore, the effect of integrin αvβ3 in the whole process of brain function recovery merits further study.
Animals ; Blood Vessels ; drug effects ; physiopathology ; Blood-Brain Barrier ; drug effects ; metabolism ; physiopathology ; Humans ; Integrin alphaVbeta3 ; antagonists & inhibitors ; metabolism ; Integrins ; metabolism ; Models, Biological ; Peptides, Cyclic ; pharmacology ; Stroke ; metabolism ; physiopathology ; Vascular Endothelial Growth Factor A ; metabolism

BACKGROUNDPeriostin originally designated osteoblast-specific factor 2 (OSF-2) is frequently found to be highly expressed in various types of human cancer cell lines in vitro and human cancer tissues in vivo. We proposed that periostin was a key factor during the process of proliferation and invasion in cancer cells. We investigated the effect of periostin on the function of human osteosarcoma cell line (U2OS), such as proliferation, apoptosis, invasion and the associated signal pathway.

METHODSA human PGCsi/U6 promoter-driven DNA template was adopted to induce short hairpin RNA (shRNA)-triggered RNA interference (RNAi) to block periostin gene expression in the cell line U2OS. U2OS cells were divided into three groups: cells transfected with phosphate buffered saline as control group (the U2OS group), cells transfected with pGCsi as negative control group (the NC group) and cells transfected with periostin/pGCsi as experimental group (the pGCsi-periostin group). Then, transfection efficiency of cell was observed under fluorescent microscope. The expressions of periostin and the related genes in cells were detected by reverse transcription polymerase chain reaction and Western Blotting. Cell viability was determined using the methyl-thiazolyl tetrazolium bromide (MTT) quantitative colorimetric assay. The invasion and migration capability of cells were tested by transwell plates with or without extracellular matrix gel. Furthermore, the changes of cell cycle and apoptosis were analyzed by flow cytometry.

RESULTSThe transfection efficiency of periostin/pGCsi to U2OS cells was about 70% - 80%. When compared with the NC group, the levels of mRNA and protein of periostin in the pGCsi-periostin group decreased by 82% (F = 564.71, P < 0.001) and 58% (F = 341.51, P < 0.001), respectively. Meantime, the earlier apoptosis value increased by 417% (F = 28.69, P < 0.001). The percentage of S phase pGCsi-periostin cells decreased by 21% (F = 47.00, P < 0.001), however, that of G0 - G1 phase cells increased by 12% (F = 14.50, P < 0.001). The capability of migration and invasion reduced by 41% (F = 17.79, P < 0.001) and 72% (F = 197.08, P < 0.001), respectively. The cell proliferation in the pGCsi-periostin group decreased by 59% and 72% at 48 and 120 hours after transfection, respectively. The mRNA expressions of transforming growth factor-β and vascular endothelial growth factor decreased by 17% (F = 73.99, P < 0.001) and 47% (F = 30.25, P < 0.001), respectively. A tendency of lower focal adhesion kinase (FAK) was shown in pGCsi-periostin cells but without any statistically significant difference. Otherwise the expression of p-FAK in those cells had markedly decreased by 21% (F = 16.81, P < 0.001).

CONCLUSIONSRNAi against periostin can effectively down-regulate periostin gene expression. Periostin increases the hyperplasia and invasion of cancer cells. Periostin might be involved in and served as a tumor promoter gene in the pathogenesis of osteosarcoma.

Apoptosis ; Bone Neoplasms ; etiology ; pathology ; Cell Adhesion Molecules ; antagonists & inhibitors ; genetics ; physiology ; Cell Cycle ; Cell Line, Tumor ; Cell Proliferation ; Focal Adhesion Protein-Tyrosine Kinases ; metabolism ; Humans ; Integrin alphaVbeta3 ; physiology ; Neoplasm Invasiveness ; Osteosarcoma ; etiology ; pathology ; Phosphorylation ; RNA Interference ; Transfection

Binding of viruses to cell surface molecules is an essential step in viral infection. In vitro studies suggested that the alpha v beta3 integrin receptor is the epithelial cell receptor for Hantaan virus (HTNV). Whether beta3 is in vivo the only or central cellular receptor for HTNV infection is not known. To investigate the role of beta3 integrin for cellular entry of HTNV, we established an HTNV infection model in newborn murine pups. Infected pups died at an average age of 14.2 +/- 1.1 days with high levels of viral antigen detected in their brain, lung, and kidney. Pre-injection of blocking monoclonal antibodies (mAb) specific for either beta3 or av prolonged survival significantly to a maximal average survival of 19.7 +/- 1.5 days (P<0.01) and 18.4 +/- 0.9 days (P<0.01), respectively. XT-199, a chemical blocker of the alpha v beta3 receptor also prolonged survival to 19.5 +/- 1.3 days (P<0.01). In contrast to these receptor blockades, anti-HTNV antibody was not only able to prolong survival, but 20% of infected pups achieved long-term survival. An anti-murine beta1 antibody comparatively prolonged survival (19.0 +/- 1.2 days), suggesting that HTNV infection is partly mediated through integrin beta1 receptors as well as through beta3 receptors in vivo. Our data demonstrate that the beta3 receptor is important for HTNV infection in vivo, but also suggest that HTNV may utilize additional receptors beyond beta3 for cellular entry within an organism.
Animals ; Animals, Newborn ; Antibodies, Monoclonal/therapeutic use ; Antigens, CD29/metabolism ; Hantaan virus/*metabolism/pathogenicity ; Hemorrhagic Fever with Renal Syndrome/mortality/*virology ; Imidazoles/pharmacology ; Integrin alphaV/metabolism ; Integrin alphaVbeta3/antagonists & inhibitors ; Integrin beta3/*metabolism ; Mice ; Receptors, Virus/*metabolism ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, P.H.S.