Humans ; Psoriasis ; etiology ; therapy ; Signal Transduction ; Vascular Endothelial Growth Factor Receptor-1 ; antagonists & inhibitors ; physiology ; Vascular Endothelial Growth Factor Receptor-2 ; antagonists & inhibitors ; physiology

The overall survival of patients with gastric cancer has increased markedly in Korea, even higher than those of developed nations in Western world. It is due to the virtue of Korean National Cancer Screening Program and nowadays more than half of patients are diagnosed at the early stage of gastric cancer. However, for patients with unresectable gastric cancer, the outcomes of traditional cytotoxic chemotherapy regimens stay at a median survival of 9-11 months. The knowledge of cancer biology and the data from gene expression profiling has explosively expanded. Alternations in the expression of receptor tyrosine kinases pathways including Human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), phosphatydyl inositol 3 kinase/mammalian target of rapamycin (PI3K/mTOR), hepatocyte growth factor receptor (HGFR/MET), and fibroblast growth factor receptor (FGFR) were proved to be critical in cancer cell survival and biological agents targeting those altered receptor tyrosine kinases, their ligands and downstream effector molecules are developed for anti-cancer purpose. Until now, only trastuzumab succeeded to significantly increase overall survival of patients with HER2 overexpressing gastric cancer. Other agents including bevacizumab, gefitinib, erlotinib, and lapatinib failed to achieve the efficacy in survival gain over standard chemotherapy. Insights about the variations between regions, races, and individuals call for the effort to find reliable predictive biomarkers for drug efficacy and to design finely stratified clinical trials. Compared to current treatment paradigms, it is hoped that molecularly targeted treatment along with conventional cytotoxic chemotherapy will lead to significant gains in survival.
Antineoplastic Agents/*therapeutic use ; Biological Markers/*metabolism ; Humans ; Molecular Targeted Therapy ; Receptor, Epidermal Growth Factor/antagonists & inhibitors/metabolism ; Receptor, erbB-2/antagonists & inhibitors/metabolism ; Stomach Neoplasms/*drug therapy/metabolism/pathology ; Vascular Endothelial Growth Factor A/antagonists & inhibitors/metabolism

The overall survival of patients with gastric cancer has increased markedly in Korea, even higher than those of developed nations in Western world. It is due to the virtue of Korean National Cancer Screening Program and nowadays more than half of patients are diagnosed at the early stage of gastric cancer. However, for patients with unresectable gastric cancer, the outcomes of traditional cytotoxic chemotherapy regimens stay at a median survival of 9-11 months. The knowledge of cancer biology and the data from gene expression profiling has explosively expanded. Alternations in the expression of receptor tyrosine kinases pathways including Human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), phosphatydyl inositol 3 kinase/mammalian target of rapamycin (PI3K/mTOR), hepatocyte growth factor receptor (HGFR/MET), and fibroblast growth factor receptor (FGFR) were proved to be critical in cancer cell survival and biological agents targeting those altered receptor tyrosine kinases, their ligands and downstream effector molecules are developed for anti-cancer purpose. Until now, only trastuzumab succeeded to significantly increase overall survival of patients with HER2 overexpressing gastric cancer. Other agents including bevacizumab, gefitinib, erlotinib, and lapatinib failed to achieve the efficacy in survival gain over standard chemotherapy. Insights about the variations between regions, races, and individuals call for the effort to find reliable predictive biomarkers for drug efficacy and to design finely stratified clinical trials. Compared to current treatment paradigms, it is hoped that molecularly targeted treatment along with conventional cytotoxic chemotherapy will lead to significant gains in survival.
Antineoplastic Agents/*therapeutic use ; Biological Markers/*metabolism ; Humans ; Molecular Targeted Therapy ; Receptor, Epidermal Growth Factor/antagonists & inhibitors/metabolism ; Receptor, erbB-2/antagonists & inhibitors/metabolism ; Stomach Neoplasms/*drug therapy/metabolism/pathology ; Vascular Endothelial Growth Factor A/antagonists & inhibitors/metabolism

OBJECTIVETo establish an in vitro homogeneous time-resolved fluorescence immunoassay method for high throughput screening of protein tyrosine kinase (PTK) inhibitors.

METHODSSpecific fluorescence signals at 670 and 612 nm were measured by multifunctional microplate reader when the fluorescence was emitted through a resonance energy transfer between fluorescent materials (EuK and XL-665). The inhibitory activity of Sunitinib, a standard PTK inhibitor, on vascular endothelia growth factor receptor 2 (VEGFR-2) kinase activity was investigated.

RESULTSA homogeneous time-resolved fluorescence immunoassay was established for high throughput screening of PTK inhibitor. In this system, the concentrations of VEGFR-2, adenosine triphosphate (ATP) and poly-peptide substrate were 5 ng/microl, 100 micromol/L and 1 micromol/L, respectively. Sunitinib inhibited VEGFR-2 kinase activity with an IC50 value of 86.7 nmol/L, which was close to the values tested using other methods.

CONCLUSIONThe homogeneous time-resolved fluorescence immunoassay we established can be easily used for high throughput screening of PTK inhibitors.

Fluoroimmunoassay ; methods ; High-Throughput Screening Assays ; methods ; Indoles ; pharmacology ; Peptides ; metabolism ; Phosphorylation ; drug effects ; Protein Kinase Inhibitors ; pharmacology ; Protein-Tyrosine Kinases ; antagonists & inhibitors ; metabolism ; Pyrroles ; pharmacology ; Time Factors ; Vascular Endothelial Growth Factor Receptor-2 ; antagonists & inhibitors ; metabolism

OBJECTIVE: Authors aimed to determine the targeting ability of vascular endothelial growth factor receptor 2 (VEGFR2)-conjugated quantum dots (QDs) in vitro, and apply it for a xenograft prostate cancer mouse model. MATERIALS AND METHODS: Conjugation reaction of QDs was performed by using the N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) and sulfo-(N-hydroxysulfosuccinimide) (Sulfo-NHS). The human umbilical vein cord endothelial cells (HUVECs) were incubated with QDs, conjugated with antiVGFR2, to see a specific binding in vitro. Fluorescent cell images were taken by a confocal microscope. The human prostate cancer cells (PC3) were injected to five nude mice on hind limbs to make the xenograft tumor model. QD-antiVEGFR2 antibody complex was injected into the tumor model and fluorescence measurements were performed at 1, 4, 9, 12, 15, and 24 hours after the injection. RESULTS: The specific interaction between HUVECs and QD-antiVEGFR2 antibody was clearly shown in vitro. The in vivo fluorescence image disclosed that there was an increased signal of tumor, 12 hours after the injection of QDs. CONCLUSION: By showing endothelial cells binding with QDs-antiVEGFR2 antibodyand an experimental application of the antibody for VEGFR2 imaging in the prostate cancer xenograft mouse model, we suggests that the antibody-conjugated QDs can be a potential imaging tool for angiogenesis of the cancer.
Animals ; Carbodiimides/pharmacology ; Cell Line, Tumor ; Disease Models, Animal ; Electrophoresis, Agar Gel ; Fluorescence ; Male ; Mice ; Mice, Nude ; Microscopy, Confocal ; Neovascularization, Pathologic/*pathology ; Prostatic Neoplasms/*pathology ; *Quantum Dots ; Succinimides/pharmacology ; Transplantation, Heterologous ; Vascular Endothelial Growth Factor Receptor-2/*antagonists & inhibitors

PURPOSE: Hypoxia-inducible factor-1alpha (HIF-1alpha) increases transcription of the vascular endothelial growth factor (VEGF) gene. Inhibition of VEGF abolishes VEGF mediated induction of HIF-1alpha. Recent reports suggested that HIF-1alpha also mediated the induction of class III beta-tubulin (TUBB3) in hypoxia. TUBB3 confers resistance to taxanes. Inhibition of VEGF may decrease the expression of HIF-1alpha and TUBB3. This study was undertaken to investigate the roles of vascular endothelial growth factor receptor (VEGFR) in gastric cancer cell behavior and to identify methods to overcome paclitaxel resistance in vitro. MATERIALS AND METHODS: The protein expression levels of HIF-1alpha and TUBB3 were measured in human gastric cancer cell lines (AGS) under normoxic and hypoxic conditions. The relationship between TUBB3 and paclitaxel resistance was assessed with small interfering TUBB3 RNA. AGS cells were treated with anti-VEGFR-1, anti-VEGFR-2, placental growth factor (PlGF), bevacizuamb, and paclitaxel. RESULTS: Hypoxia induced paclitaxel resistance was decreased by knockdown of TUBB3. Induction of HIF-1alpha and TUBB3 in AGS is VEGFR-1 mediated and PlGF dependent. Hypoxia-dependent upregulation of HIF-1alpha and TUBB3 was reduced in response to paclitaxel treatment. Expressions of HIF-1alpha and TUBB3 were most decreased when AGS cells were treated with a combination of paclitaxel and anti-VEGFR-1. AGS cell cytotoxicity was most increased in response to paclitaxel, anti-VEGFR-1, and anti-VEGFR-2. CONCLUSION: We suggest that blockade of VEGFR-1 and VEGFR-2 enhances paclitaxel sensitivity in TUBB3-expressing gastric cancer cells.
Angiogenesis Inhibitors/pharmacology ; Antibodies, Monoclonal, Humanized/pharmacology ; Antineoplastic Agents, Phytogenic/*pharmacology ; Cell Hypoxia ; Cell Line, Tumor ; *Drug Resistance, Neoplasm ; Gene Expression Regulation, Neoplastic/drug effects ; Gene Knockdown Techniques ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism ; Paclitaxel/*pharmacology ; Pregnancy Proteins/pharmacology ; Stomach Neoplasms/drug therapy/genetics ; Tubulin/genetics/metabolism ; Vascular Endothelial Growth Factor Receptor-1/antagonists & inhibitors/*physiology ; Vascular Endothelial Growth Factor Receptor-2/antagonists & inhibitors/*physiology

The purpose of this study was to devise an expanded ischemic flap model and to investigate the role of AMD-3100 (Plerixafor, chemokine receptor 4 inhibitor) in this model by confirming its effect on mobilization of stem cells from the bone marrow. Male Sprague-Dawley rats were used as an animal research model. The mobilization of stem cells from the bone marrow was confirmed in the AMD-3100-treated group. The fractions of endothelial progenitor cells (EPC) and the vascular endothelial growth factor receptor (VEGFR) 2+ cells in the peripheral blood were increased in groups treated with AMD-3100. The expression of vascular endothelial growth factor (VEGF) was increased in response to expansion or AMD injection. The expression of stromal cell derived factor (SDF)-1 and VEGFR2 were increased only in unexpanded flap treated with AMD-3100. Treatment with AMD-3100 increased both the number and area of blood vessels. However, there were no statistically significant differences in the survival area or physiologic microcirculation in rats from the other groups. This endogenous neovascularization induced by AMD-3100 may be a result of the increase in both the area and number of vessels, as well as paracrine augmentation of the expression of VEGF and EPCs. However, the presence of a tissue expander under the flap could block the neovascularization between the flap and the recipient regardless of AMD-3100 treatment and expansion.
Animals ; Anti-HIV Agents/pharmacology ; Bone Marrow Cells/cytology ; Chemokine CXCL12/biosynthesis ; Endothelial Progenitor Cells/*cytology ; Hematopoietic Stem Cells/*cytology ; Heterocyclic Compounds/*pharmacology ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism ; Male ; Neovascularization, Physiologic ; Nitric Oxide Synthase Type III/metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, CXCR4/antagonists & inhibitors ; Surgical Flaps/*blood supply/surgery ; Tissue Expansion/*methods ; Vascular Endothelial Growth Factor A/biosynthesis ; Vascular Endothelial Growth Factor Receptor-2/biosynthesis/metabolism

Gastric cancer overexpressing the human epidermal growth factor 2 (HER2) protein has a poor outcome, although a combination of chemotherapy and the anti-HER2 antibody trastuzumab has been approved for the treatment of advanced gastric cancer. Vascular endothelial growth factor (VEGF) expression in gastric cancer is correlated with recurrence and poor prognosis; however, the anti-VEGF antibody bevacizumab has shown limited efficacy against gastric cancer in clinical trials. In this study, we evaluated the antitumor effects of trastuzumab; VEGF-Trap binding to VEGF-A, VEGF-B and placental growth factor (PlGF); and a combination of trastuzumab and VEGF-Trap in a gastric cancer xenograft model. Although trastuzumab and VEGF-Trap each moderately inhibited tumor growth, the combination of these agents exerted greater inhibition compared with either agent alone. Immunohistochemical analyses indicated that the reduction in tumor growth was associated with decreased proliferation and increased apoptosis of tumor cells and decreased tumor vascular density. The combined treatment resulted in fewer proliferating tumor cells, more apoptotic cells and reduced tumor vascular density compared with treatment with trastuzumab or VEGF-Trap alone, indicating that trastuzumab and VEGF-Trap had additive inhibitory effects on the tumor growth and angiogenesis of the gastric cancer xenografts. These data suggest that trastuzumab in combination with VEGF-Trap may represent an effective approach to treating HER2-overexpressing gastric cancer.
Animals ; Antibodies, Monoclonal, Humanized/administration & dosage/*therapeutic use ; Antineoplastic Combined Chemotherapy Protocols/*therapeutic use ; Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Humans ; Mice ; Mice, Inbred BALB C ; Neovascularization, Pathologic/drug therapy ; Receptor, erbB-2/*antagonists & inhibitors ; Receptors, Vascular Endothelial Growth Factor/administration & dosage/*therapeutic use ; Recombinant Fusion Proteins/administration & dosage/*therapeutic use ; Stomach Neoplasms/*drug therapy/pathology ; Vascular Endothelial Growth Factor A/antagonists & inhibitors ; Xenograft Model Antitumor Assays

BACKGROUND AND OBJECTIVEStudies have shown that nitric oxide (NO) derived from endothelial nitric oxide synthase (eNOS) is expressed widely in tumor tissues and regulates tumor angiogenesis. However, the results are controversial. This study was to investigate the effect of NO on tumor angiogenesis and its mechanism.

METHODSC57BL/6 mice inoculated with Lewis lung cancer cells were randomly divided into three groups. Mice in the NO group were inoculated with lung cancer cells transfected with eNOS gene, mice in the L-NAME group with L-NAME, an eNOS antagonist, and mice in the control group with normal saline. Plasma concentration of NO and the number of endothelial progenitor cells (EPCs) in peripheral blood were detected . Tumor vessel density, CD133+ cells, and the expression of VEGF-VEGFR in tumor tissues were also measured.

RESULTSFour weeks after inoculation of Lewis cells, tumor volume was significantly larger in control group [ (3022 +/- 401) mm(3)] than in the L-NAME group [ (1204 +/-97) ) mm(3)] and in the eNOS group [(1824 +/- 239) mm(3)] (P<0.01). eNOS protein and NO production increased significantly in Lewis lung cancer cells transfected with eNOS gene. But the number of CD133-positive cells and vessel density in tumors were significantly lower in the eNOS group than in the control group [(48+/-19) / HPF vs. ( 103 +/- 27)/ HPF, (19+/- 7) HPF vs. (31 +/- 9) HPF, P<0.05]. The number of EPCs in peripheral blood was not statistically different between each group. The levels of NO in blood and tumor tissue significantly decreased after the treatment of L-NAME, while the tumor vessel density reduced to 12+/- 5/ HPF (P<0.01, vs. the control group; P<0.05, vs the eNOS transfected group). The number of EPCs in blood and that of CD133-positive cells in tumor tissue were significantly smaller in the L-NAME group than in the control group (P<0.05).

CONCLUSIONNo derived from eNOS inhibits angiogenesis and tumor growth, which may be due to its suppression on either the mobilization or homing of EPCs via VEGF binding to VEGFR.

AC133 Antigen ; Animals ; Antigens, CD ; metabolism ; Carcinoma, Lewis Lung ; blood supply ; metabolism ; pathology ; Cell Count ; Cells, Cultured ; Endothelium, Vascular ; pathology ; Enzyme Inhibitors ; pharmacology ; Female ; Glycoproteins ; metabolism ; Mice ; Mice, Inbred C57BL ; Microvessels ; pathology ; NG-Nitroarginine Methyl Ester ; pharmacology ; Neoplasm Transplantation ; Neovascularization, Pathologic ; Nitric Oxide ; blood ; metabolism ; Nitric Oxide Synthase Type III ; antagonists & inhibitors ; genetics ; metabolism ; Peptides ; metabolism ; Plasmids ; Random Allocation ; Stem Cells ; metabolism ; pathology ; Transfection ; Tumor Burden ; Vascular Endothelial Growth Factor A ; blood ; metabolism ; Vascular Endothelial Growth Factor Receptor-2 ; metabolism

OBJECTIVE: To visualize tumor angiogenesis using the MRI contrast agent, Gd-DTPA-anti-VEGF receptor 2 antibody conjugate, with a 4.7-Tesla MRI instrument in a mouse model. MATERIALS AND METHODS: We designed a tumor angiogenesis-targeting T1 contrast agent that was prepared by the bioconjugation of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) and an anti-vascular endothelial growth factor receptor-2 (VEGFR2) antibody. The specific binding of the agent complex to cells that express VEGFR2 was examined in cultured murine endothelial cells (MS-1 cells) with a 4.7-Tesla magnetic resonance imaging scanner. Angiogenesis-specific T1 enhancement was imaged with the Gd-DTPA-anti-VEGFR2 antibody conjugate using a CT-26 adenocarcinoma tumor model in eight mice. As a control, the use of the Gd-DTPA-anti-rat immunoglobulin G (Gd-DTPA-anti-rat IgG) was imaged with a tumor model in eight mice. Statistical significance was assessed using the Mann-Whitney test. Tumor tissue was examined by immunohistochemical analysis. RESULTS: The Gd-DTPA-anti-VEGFR2 antibody conjugate showed predominant binding to cultured endothelial cells that expressed a high level of VEGFR2. Signal enhancement was approximately three-fold for in vivo T1-weighted MR imaging with the use of the Gd-DTPA-anti-VEGFR2 antibody conjugate as compared with the Gd-DTPA-rat IgG in the mouse tumor model (p < 0.05). VEGFR2 expression in CT-26 tumor vessels was demonstrated using immunohistochemical staining. CONCLUSION: MR imaging using the Gd-DTPA-anti-VEGFR2 antibody conjugate as a contrast agent is useful in visualizing noninvasively tumor angiogenesis in a murine tumor model.
Adenocarcinoma/*pathology ; Animals ; Colonic Neoplasms/*pathology ; Contrast Media/chemistry/*diagnostic use ; Gadolinium DTPA/chemistry/*diagnostic use ; Immunoenzyme Techniques ; Magnetic Resonance Imaging/*methods ; Mice ; Mice, Nude ; Neovascularization, Pathologic/*diagnosis ; Rats ; Statistics, Nonparametric ; Tumor Cells, Cultured ; Vascular Endothelial Growth Factor Receptor-2/*antagonists & inhibitors/chemistry