Tumor angiogenesis is a complicated process in which VEGF and the members of Ang family have been proposed to play an important role. Ang family is the only vascular growth factor family including activators and inhibitors. They can all bind with specific tyrosine kinase receptor Tie-2 and participate in angiogenesis. Vascular endothelial growth factor (VEGF) is secreted by tumor cells and coordinates with Ang to promote angiogenesis. Further research on the structure and functional mechanism of VEGF and Ang will contribute to develop a new type of antiangiogenesis medicine, which might have good perspect in clinical practice. In this paper, the structure and action mechanism of Ang family and its receptor Tie-2, the application of Ang family and Tie in tumor therapy, and the synergic mechanism between Ang and VEGF were summarized.
Angiogenesis Inhibitors ; pharmacology ; Angiopoietin-2 ; pharmacology ; Animals ; Drug Synergism ; Humans ; Neoplasms ; blood supply ; Neovascularization, Pathologic ; prevention & control ; Vascular Endothelial Growth Factors ; pharmacology

OBJECTIVETo establish an implanted model of human colonic carcinoma on chick embryo, and to study the effects of anti-angiopoietin-2 antibody on its vascularization.

METHODSThe human colonic adenocarcinoma cell line HT-29 was transplanted on the chick embryo's chorioallantoic membrane(CAM), and the angiogenesis characteristics were observed by stero-microscope, light microscope and immunohistochemistry. Furthermore, the effects of anti-angiopoietin-2 antibody on angiogenesis and tumor growth were also investigated.

RESULTSThree to seven days after HT-29 cell line was implanted into CAM, tumors grew rapidly and new blood vessels grew toward tumors. Five days after anti-angiopoietin-2 antibody was given, the number of blood vessels in anti-angiopoietin-2 antibody group was significantly down-regulated than that in tumor control group observed by stero-microscope (37.2+/-4.6 vs 56.8+/-7.4, P<0.01), but was up-regulated than that in normal control group (37.2+/-4.6 vs 9.6+/-2.4, P<0.01). Microvessel density(MVD) in anti-angiopoietin-2 antibody group was much lower than that in tumor control group by histological examination (9.6+/-2.4 vs 20.2+/-5.8, P<0.01).

CONCLUSIONAngiopoietin-2 antibody is able to inhibit the angiogenesis induced by colorectal cancer cell line HT-29 obviously. The anti-angiopoietin-2 antibody may be potentially useful for clinical treatment of colonic carcinoma.

Angiopoietin-2 ; immunology ; Animals ; Antibodies, Monoclonal ; pharmacology ; Chick Embryo ; Colonic Neoplasms ; blood supply ; HT29 Cells ; drug effects ; Humans ; Neoplasm Transplantation ; Neovascularization, Pathologic

Objective To explore the effect and mechanism of penehyclidine hydrochloride (PHCD) on vascular endothelial injury in septic rats. Methods Fifty male SD rats were randomly divided into control group, lipopolysaccharide (LPS) induced sepsis group (model group), low dose PHCD (0.3 mg/kg) group, medium dose PHCD (1.0 mg/kg) group and high dose PHCD (3.0 mg/kg) groups, ten mice for each group. Normal saline was injected into the tail vein of the control group, and 10 mg/kg lipopolysaccharide (LPS) was injected into the tail vein of the rats in other groups to prepare the sepsis rat models. After the models were successfully established, low, medium and high doses (0.3, 1.0, 3.0 mg/kg) of PHCD solution were injected into the tail vein of the rats of corresponding groups. Wet/dry mass ratio (W/D) of lung tissue of rats in each group was measured, and ELISA was used to assay interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), IL-6 content and rat plasma angiopoietin 2 (Ang2) content in bronchoalveolar lavage fluid (BALF). HE staining was used to observe the pathological changes of lung tissues. Immunohistochemical staining was used to observe the expression of Ang2 in the right lung tissues. Western blot analysis was performed to detect Ang2 and vascular endothelial cadherin (VE-cadherin) protein in lung tissues. Results Compared with the control group, the W/D ratio of the lung tissues of rats in the model group and the contents of IL-1β, IL-6 and TNF-α in BALF were significantly increased; the lung tissues showed obvious pathological damage, with up-regulation of Ang2 expression and down-regulation of VE-Cadherin expression. Compared with the model group, the W/D ratio of the lung tissues of rats in three PHCD treatment groups and the contents of IL-1β, IL-6 and TNF-α in BALF were significantly reduced; the pathological damage of lung tissue was significantly reduced, with down-regulation of Ang2 expression and up-regulation of VE-cadherin expression. Conclusion PHCD can reduce LPS-induced lung inflammation in rats with sepsis by regulating the Ang2/VE-Cadherin pathway, thereby improving vascular endothelial injury.
Rats ; Mice ; Animals ; Male ; Lipopolysaccharides/metabolism* ; Tumor Necrosis Factor-alpha/metabolism* ; Angiopoietin-2/pharmacology* ; Interleukin-6/metabolism* ; Rats, Sprague-Dawley ; Lung ; Acute Lung Injury/metabolism* ; Sepsis/metabolism*

BACKGROUNDAngiopoietin-1 (Ang-1) is an endothelial-specific growth factor that can promote angiogenesis. Studies demonstrated that Ang-1 can inhibit apoptosis of umbilical endothelial cells, but so far little is known about its effects on apoptosis of microvascular endothelial cells. With the apoptotic model of murine-cerebral-derived microvascular endothelial cells (bEnd.3) induced by serum-free culture, we attempted to clarify the molecular mechanism of bEnd.3 apoptosis, particularly its relation to cytochrome C (Cyt C).

METHODSThe cultured microvascular endothelial cell strain, bEnd.3 cell, was employed. An apoptotic model of bEnd.3 was established by serum-free culture. Flow cytometry after Annexin labeling and PI staining were used to assess the apoptotic effects of Ang-1 on bEnd.3, and the expression of Bax/Bcl-2, caspase 8, caspase 3, and Cyt C were detected with Western blotting and ELISA.

RESULTSThe apoptotic rate of bEnd.3 cells after stimulation with Ang-1 (100 ng/L) in serum-free medium was significantly higher than that in control group. Ang-1 inhibited early-stage apoptosis more than late-stage apoptosis provided by propidium iodide (PI) and AnnexinV double staining. The inhibition of Ang-1 on bEnd.3 cell apoptosis was strengthened with the increase in concentration (0 - 400 ng/ml). Ang-1 could decrease the expression of Bax, caspase3 and 8, and increase that of Bcl-2. The results of ELISA indicated that Ang-1 significantly decreased CytC content in cytoplasm and increase that in mitochondria.

CONCLUSIONSAng-1 could inhibit bEnd.3 apoptosis induced by serum-free medium culture. The apoptosis was associated with decreased Bax expression, increased Bcl-2 expression, which result in Cyt C transferring from mitochondria to cytoplasm, and then caspases activation are reduced and cell apoptosis is suppressed.

Angiopoietin-1 ; pharmacology ; Animals ; Annexin A5 ; analysis ; Apoptosis ; drug effects ; Caspase 3 ; Caspase 8 ; Caspases ; analysis ; Cells, Cultured ; Cytochromes c ; physiology ; Endothelial Cells ; cytology ; drug effects ; Mice ; Microcirculation ; drug effects ; bcl-2-Associated X Protein ; analysis

Acute graft-versus-host disease (aGVHD) is a serious complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the mechanisms of aGVHD are not well understood. We aim to investigate the roles of the three angiogenic factors: angiopoietin-1 (Ang-1), Ang-2 and vascular endothelial growth factor (VEGF) in the development of aGVHD. Twenty-one patients who underwent allo-HSCT were included in our study. The dynamic changes of Ang-1, Ang-2 and VEGF were monitored in patients before and after allo-HSCT. In vitro, endothelial cells (ECs) were treated with TNF-β in the presence or absence of Ang-1, and then the Ang-2 level in the cell culture medium and the tubule formation by ECs were evaluated. After allo-HSCT, Ang-1, Ang-2 and VEGF all exhibited significant variation, suggesting these factors might be involved in the endothelial damage in transplantation. Patients with aGVHD had lower Ang-1 level at day 7 but higher Ang-2 level at day 21 than those without aGVHD, implying that Ang-1 may play a protective role in early phase yet Ang-2 is a promotion factor to aGVHD. In vitro, TNF-β promoted the release of Ang-2 by ECs and impaired tubule formation of ECs, which were both weakened by Ang-1, suggesting that Ang-1 may play a protective role in aGVHD by influencing the secretion of Ang-2, consistent with our in vivo tests. It is concluded that monitoring changes of these factors following allo-HSCT might help to identify patients at a high risk for aGVHD.
Acute Disease ; Adolescent ; Adult ; Angiogenesis Inducing Agents ; immunology ; metabolism ; pharmacology ; Angiopoietin-1 ; genetics ; immunology ; pharmacology ; Angiopoietin-2 ; genetics ; immunology ; pharmacology ; Antineoplastic Agents ; therapeutic use ; Female ; Gene Expression Regulation, Neoplastic ; Graft vs Host Disease ; genetics ; immunology ; pathology ; Hematopoietic Stem Cell Transplantation ; Human Umbilical Vein Endothelial Cells ; cytology ; drug effects ; immunology ; Humans ; Leukemia, Myeloid ; genetics ; immunology ; pathology ; therapy ; Lymphoma, Non-Hodgkin ; genetics ; immunology ; pathology ; therapy ; Male ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; genetics ; immunology ; pathology ; therapy ; Retrospective Studies ; Signal Transduction ; Transplantation, Homologous ; Tumor Necrosis Factor-alpha ; pharmacology ; Vascular Endothelial Growth Factor A ; genetics ; immunology

OBJECTIVETo investigate the effect of RNA interference mediated angiopoietin-2 (ANG-2) gene silencing on human endometrial carcinoma cell line Ishikawa.

METHODSShort hairpin RNA (shRNA) targeting ANG-2 gene was designed and transfected into Ishikawa cells with Lipofectamine 2000. The mRNA and protein expression level of ANG-2, proliferation, morphological changes, apoptosis, cell cycle and invasive ability of the cells after transfection were analyzed.

RESULTSThe shRNA targeting the human ANG-2 gene effectively decreased the expression of ANG-2 on both mRNA and protein level, the proliferation inhibition rate of the Ishikawa cells was 63.11%, cell apoptosis was induced, and the cell cycle was arrested in G1 phase. The apoptotic rate of the Ishikawa cells in the transfected group was significantly higher, and the invasive ability was decreased markedly, than that of control groups.

CONCLUSIONThe shRNA targeting human ANG-2 gene could reduce ANG-2 expression, inhibit cellular growth and invasion in Ishikawa cells in vitro.

Angiopoietin-2 ; antagonists & inhibitors ; genetics ; Apoptosis ; drug effects ; genetics ; Cell Cycle ; drug effects ; genetics ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Endometrial Neoplasms ; genetics ; pathology ; Female ; Gene Expression ; drug effects ; Gene Expression Regulation, Neoplastic ; Gene Silencing ; drug effects ; physiology ; Humans ; Indicators and Reagents ; Lipids ; pharmacology ; RNA Interference ; RNA, Small Interfering ; genetics ; pharmacology ; Transfection ; Tumor Cells, Cultured

AIM(1) To investigate the mRNA expression of the key angiogenic growth factors in the grafts after transplantation. (2) To investigate the potential impact of danshen (Chinese traditional medicine) administration on grafts angiogenesis.

METHODSThe frozen-thawed ovarian tissue from aborted fetus were xenografted into the renal capsule of the nude mice, recovered 48 h, 7 d and 28 d after respectively. Either danshen or saline (as the control) was administered after transplantation.

RESULTSThe mRNA levels of VEGF showed a temporary raise in 48 h after transplantation, then decreased in one week, and no significant difference was fund between the control group and danshen group. Ang-2 was increased in 48 h after transplantation, when Danshen group was significantly higher than the control group (P < 0.05). The microvessel density significantly increased in all the tissues after transplantation. The control group peaked on day 7 after transplantation, while danshen group peaked in 48 h and kept correspondingly steady after that.

CONCLUSIONEarly angiogenesis began within 48 h after transplantation of the thawed human fetal ovarian tissue, and its microvessel density peaked within the first week after transplantation. Our results also suggested that the use of danshen injection in conjunction with transplantation could facilitate revascularization of the grafts.

Angiopoietin-2 ; genetics ; metabolism ; Animals ; Cryopreservation ; Drugs, Chinese Herbal ; pharmacology ; Female ; Fetal Tissue Transplantation ; methods ; Fetus ; Humans ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Neovascularization, Physiologic ; drug effects ; Ovarian Follicle ; cytology ; growth & development ; transplantation ; RNA, Messenger ; genetics ; metabolism ; Salvia miltiorrhiza ; chemistry ; Transplantation, Heterologous ; methods ; Vascular Endothelial Growth Factor A ; genetics ; metabolism