Angiostatin Works as Immune Modulatory Molecules via Inhibition of Neutrophil Activation and Migration

Angiostatin is derived from enzymatic degradation of plasminogen and it has endogenous anti-angiogenic properties. Although tumor cells, macrophages, platelets, and neutrophils generate high amount of angiostatin, its expression is increased in inflammatory conditions. Moreover, angiostatin binds to integrin alpha(v)beta(3), ATP synthase, and angiomotin, which expressed on neutrophils. Activated neutrophils are essential to innate immune response, but also cause tissue damage through production of reactive oxygen species (ROS) and increase lifespan. In this article, it suggests several mechanism of angiostatin as immune regulator for neutrophils in inflammatory conditions; complex with integrin alpha(v)beta(3) and F(1)F(0) ATP synthase on lipid raft, attenuate polarization, and ROS production. These data provide possible exploit of double-edged role of neutrophils in acute inflammatory pathologies to preserve beneficial effect and minimize tissue damage.

Effect of yifei qinghua granule on VEGF, bFGF, angiostatin, and endostatin in Lewis lung cancer mice: an experimental study / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe the effect of Yifei Qinghua Granule (YQG) on vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), angiostatin, and endostatin in tumor tissue of Lewis Lung cancer mice, and to explore its anti-tumor mechanisms.</p><p><b>METHODS</b>Totally 70 C57BL/6 mice were randomly divided into the model group, the low, medium, and high dose YQG groups, the gefitinib group, the gefitinib plus medium dose YQG group, and the cyclophosphamide (CTX) group, 10 in each group. The models were established by subcutaneously injecting Lewis lung cancer cells from the right axilla of C57BL/6 mice. Mice in the model group were given with 0.4 mL pure water by gastrogavage, once daily. Mice in the low and medium dose YHG groups were given with YHG at the daily dose of 5 and 10 g/kg by gastrogavage, once daily. Those in the high dose YHG group were given with YHG at 10 g/kg by gastrogavage, twice daily. Those in the gefitinib group were given with gefitinib 100 mg/ kg by gastrogavage, once daily. Those in the gefitinib plus medium dose YHG group were given with gefitinib at 100 mg/kg by gastrogavage in the morning and YHG at 10 g/kg by gastrogavage in the afternoon. All medication was started from the 2nd day of inoculation, lasting 14 successive days. Those in the CTX group were given CTX at 60 mg/kg by peritoneal injection on the 3rd and the 7th day of the experiment. Mice were sacrificed at the fifteenth day of the experiment. Tumors were taken out. Expressions of VEGF, bFGF, angiostatin, and endostatin in the tumor tissue were detected using immunohistochemical assay.</p><p><b>RESULTS</b>Compared with the model group, the expression of VEGF significantly decreased, expressions of angiostatin and endostatin significantly increased in each group (P < 0.01). The expression of bFGF significantly decreased in the gefitinib group (P < 0.05). There was no statistical difference in VEGF among all groups (P > 0.05). The angiostatin expression was significantly higher in the CTX group than in the low dose YQG group (P < 0.01). The expression of endostatin was significantly higher in the high dose YQG group and the gefitinib plus medium dose YQG group than in the low and the medium dose YQG groups (P < 0.01). The expression of endostatin was significantly higher in the gefitinib plus medium dose YQG group than in the gefitinib group (P < 0.05).</p><p><b>CONCLUSION</b>The action mechanism of YQG in treating lung cancer might be achieved through reducing the expression of angiogenesis promoting factor VEGF and increasing expressions of angiogenesis inhibitors angiostatin and endostatin.</p>

Efeito da proteína Kint3-4 do plasminogênio humano no crescimento do tumor de Ehrlich / Kint3-4 protein from human plasminogen delays Ehrlich tumor growth in mice

INTRODUCTION AND OBJECTIVE: Kint3-4 protein, originated from a genetic recombination of K1-3 and K1-4 human plasminogen segments, is recognized for its antiangiogenic and anti-inflammatory potential. This study aimed to evaluate the effect of Kint3-4 protein on tumor development in Swiss mice previously inoculated with Ehrlich tumor cells. METHODS: The protein fragment was obtained from Pichia pastoris cloning and transformation. After tumor cell inoculation three different protocols were used to assess tumor growth: beginning (0-6 days), peak (0-12 days) and after peak (0-18 days). We analyzed tumor growth, histomorphological characteristics and immunohistochemistry by use of CDC47 (cellular proliferation marker) and CD31 (blood vessel marker). RESULTS: Animals treated with Kint3-4 protein (150 µg/kg/48 h) showed lower tumor growth in all protocols. Based on histological assessment, inflammation and tumor areas were also reduced. Moreover, both the lowest rate of tumor cell proliferation and low microvessel density were observed in animals treated with Kint3-4 protein compared with the untreated control group. CONCLUSION: The effect of Kint3-4 recombinant protein on tumor angiogenesis and control of malignant cell proliferation enhances the prospects of its use in clinical and antiangiogenic treatment.

INTRODUÇÃO E OBJETIVO: A proteína Kint3-4 originou-se a partir de uma recombinação genética dos segmentos K1-3 e K1--4 do plasminogênio humano e é reconhecida por seu potencial anti-inflamatório e antiangiogênico. Este estudo teve como objetivo avaliar o efeito da proteína Kint3-4 no desenvolvimento de tumores em camundongos inoculados com células do tumor de Ehrlich. MÉTODOS: O fragmento de proteína foi obtido por uma técnica de clonagem e transformação de Pichia pastoris. Três diferentes protocolos foram avaliados após a inoculação das células tumorais: no início (0-6 dias), no pico (0-12 dias) e após o pico (0-18 dias) de crescimento do tumor. Foram analisados o crescimento do tumor e as características histomorfológica e imuno-histoquímica com CDC47 (marcador de proliferação celular) e CD31 (marcador de vasos sanguíneos). RESULTADOS: Os animais tratados com a proteína Kint3-4 (150 µg/kg/48 h) nos três diferentes protocolos apresentaram menor crescimento do tumor. Áreas de inflamação e tumor também foram reduzidas, avaliadas por exame histológico. Além disso, a menor taxa de proliferação das células tumorais e a baixa densidade de microvasos foram observadas nos animais tratados com proteína Kint3-4 em comparação com o grupocontrole. CONCLUSÃO: A participação da proteína recombinante Kint3-4 na angiogênese tumoral e no controle da proliferação de células malignas abre perspectivas para seu uso no tratamento clínico como antiangiogênico.

The cloning expression, purification and activity of human angiostatin K (1-3) gene / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To clone the sequence of human Angiostatin cDNA and obtain the protein of recombinant angiostatin for further development.</p><p><b>METHODS</b>Fresh human liver tissue was used for the extraction of total RNA and amplified the Angiostatin cDNA through RT-PCR method . After the recombinant plasmid pET30a-Angiostatin was constructed and confirmed, it was transduced into Rosetta (DE3). Then the transformation was used for fermentation and induced expression. The protein was identified by Western Blot and purified by Ni-NTA affinity chromatography.</p><p><b>RESULTS</b>The sequence of human Angiostatin cDNA was identical with genebank. Angiostatin (K1-3) was expressed and purified. The target protein made up 30% of the total bacterial protein. The purity is above 90%.</p><p><b>CONCLUSION</b>Angiostatin K (1-3) can be reached using fusion vector pET30a. The product have the biological activity.</p>

Observation of the changes in ventral prostatic microcirculation in castrated rats / 中华男科学杂志

<p><b>OBJECTIVE</b>Castrated rats exhibit significant shrinkage of the ventral prostate and apoptosis of prostatic cells, which can be attributed to the reduced blood supply to the prostate. But what causes the blood decrease in the prostate remains unknown. This study aims to explore the molecular mechanism of the changes in the microcirculation of the ventral prostate of rats following castration.</p><p><b>METHODS</b>We randomized 24 male adult rats into 6 groups of equal number, and collected their ventral prostates at 0, 1/2, 1, 2, 3 and 7 d, respectively, after castration. Then we observed the changes of the microvessels under the transmission electron microscope, detected the apoptosis of endothelial cells by TUNEL, and determined the expressions of VEGF, endostatin, angiostatin and angiopoietin-2 by Western blot.</p><p><b>RESULTS</b>The castrated rats showed dramatic changes in the microvessels of the ventral prostate, obvious apoptosis of the endothelial cells, down-regulated expression of VEGF, and up-regulated expressions of endostatin and angiostatin, while angiopoietin-2 remained unchanged.</p><p><b>CONCLUSION</b>The decreased level of VEGF and increased levels of endostatin and angiostatin might underlie the mechanism of the changes in the microcirculation of the ventral prostate of rats following castration.</p>

Treatment of intraperitoneal implanted human ovarian carcinoma of nude mice by angiostatin gene and chemotherapy in vivo / 中国医学科学院学报

<p><b>OBJECTIVE</b>To observe the effects of angiostatin gene combined with chemotherapy on implanted human ovarian carcinoma of nude mouse.</p><p><b>METHODS</b>The mice were randomly divided into four groups after 7 days of the intraperitoneal injection of tumor cells (4 x 10(6)), and injected respectively with empty plasmid pcDNA3.0, angiostatin plasmid, cisplatin, and angiostatin plasmid + cisplatin. For combinational treatment, reagents were delivered in a timed fashion, where angiostatin plasmid was injected first, followed by cisplatin 24h later. The tumor samples were prepared to be used in the examinations of the expression of angiostatin with immunohistochemistry, of MVD in the tumor with immunohistochemistry, and of cell apoptosis with TUNEL staining.</p><p><b>RESULTS</b>Tumor growth and ascites formation were inhibited in all 3 groups except for the control group. The therapeutic effectiveness in the combined group was more significant than in the other two groups. In this group, MVD (32.5 +/- 4.3) was the lowest and apoptosis index (5.12 +/- 0.63) was the highest (P < 0.01).</p><p><b>CONCLUSIONS</b>Angiostatin gene therapy combined with chemotherapy has a synergistic effect on the inhibition of ovarian cancer angiogenesis and ascites formation. Combining multiple therapies to treat ovarian cancer is an effective strategy.</p>

Relationship between changes of serum concentrations of antiangiogenic factors and disease progression in patients of pancreatic carcinoma / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the relationship between TSP-1, Angiostatin and Endostatin serum concentrations and progression of pancreatic adenocarcinoma.</p><p><b>METHODS</b>Fifty-six patients with suspected pancreatic cancer were enrolled in the study and divided into resectable group (n = 32) and unresectable group (n = 24) according to evaluation and staging with dual phase helical CT. Histopathologic examinations included postoperative final pathology and preoperative fine needle biopsies. Peripheral blood concentrations of antiangiogenic factors Angiostatin, Endostatin and TSP-1 were detected by using ELISA methods, selecting samples of health people as a control.</p><p><b>RESULTS</b>Serum concentrations of antiangiogenic factors in pancreatic cancer group were significantly higher than those in health group (P < 0.01). Serum concentrations of Endostatin, Angiostatin and TSP-1 were significantly increased in unresectable group, and highly expressed in patients whom tumor sizes were greater than 2 cm and tumor invaded peripancreatic great vessels (P < 0.05). After operation, serum concentrations of Endostatin, Angiostatin and TSP-1 significantly decreased (P < 0.05). There were no significant difference between I, II stage group and III, IV group.</p><p><b>CONCLUSIONS</b>Detection of serum concentrations of antiangiogenic factors may be used to evaluate the resectability of pancreatic cancer and may play important roles in growth, invasion and metastasis of pancreatic cancer.</p>

Inhibitory effect of combined transfection of p53 and AS genes on K562 cell proliferation / 中国实验血液学杂志

This study was aimed to investigate the inhibitory effect of combined transfection of p53 and angiostatin (AS) genes on K562 cells and to explore its mechanism. pVTRIO2-hp53-hAS was transfected into K562 cells with lipofectamine 2000, RT-PCR was used to determine the expression of gene of interest in transfected cells, MTT growth curve and flow cytometry were used to analyze the cell cycle for observation biological changes of cells, the cellular immunochemistry assay was used to observe the expression differences between VEGF, Bcl-2 and Bax proteins. The results indicated that the genes of interest have been transfected and stably expressed, the increase of K562 with genes of interest was slower than that without genes of interest (p<0.05). And the increase of K562 in double gene group was slower than that in p53 and AS groups (0.264+/-0.011 at last day A290 nm; 0.652+/-0.039 at last day A290 nm; 0.604+/-0.017 at last day A290 nm respectively) (p<0.05). After transfection, the expressions of VEGF and Bcl-2 protein decreased, but the expressions of Bax increased. It is concluded that the combined transfection of p53 and AS genes into K562 cells shows more notable and powerful inhibition on proliferation than those transfected with single one gene. The synergistic mechanism of p53 and AS genes may be commonly influenced the pathway of Bcl-2 and Bax expression.

Constitutive expression of human angiostatin in Pichia pastoris using glycerol as only carbon source / 生物工程学报

Carbon source plays an important role in the constitutive expression of foreign proteins in Pichia pastoris. In present study, glucose , glycerol , methanol and oil acid, was used respectively as the only carbon source to constitutively express hAS in Pichia pastoris GS115 (pGAP9K-AS)in shaking flask. The result shows that oleic acid is the best (163 mg/L) compared with glycerol (83mg/L), glucose (76 mg/L)and methanol (57 mg/L). Since oleic acid is insoluble in water, glycerol was used as the carbon source in the high-density cell culture of GS115 (pGAP9K-AS) in a 30 liter bioreactor and 169 mg/L of angiostatin was obtained after 48h of culture. The expressed angiostatin is immunologically active as shown by Western blotting. The recombinant hAS inhibits bFGF induced CAM angiogenesis and suppresses the growth of B16 melanoma in C57BL/6J mice. The tumor inhibition rate is 90% after 12 days of treatment. Statistics analysis revealed that the tumor volume difference of mice between the hAS group and PBS group is prominent (P < 0.01).

Fusion expression and identification of angiostatin and endostatin in E. coli BL21(DE3) / 生物医学工程学杂志

Angiostatin(AS) and endostatin(ES) are both potent endogenous angiogenesis inhibitors, and the combination of AS and ES has been shown to have synergistic antiangiogenic effects. Here we report the fusion protein AS-ES expressed in E. coli which has antiangiogenic effects. At first, AS and ES genes were cloned respectively through RT-PCR, then fusion gene was made through gene splicing ,finally pET-42 (b)/AS-ES expression plasmid was constructed and transduced in E. coli BL21 (DE3). Target protein was in form of inclusion body,the rate of expression was about 14%, and MW about 65KD. Western blotting assay showed expressed protein had specific immune reaction to both the antibodies of AS and ES. The expressed protein which was refolded and purified through heparin affinity chromatography had antiangiogenic effect to vessels on chicken embryo chorioallantoic membrane. The results show that fusion protein AS-ES was expressed successfully in E. coli, and the expressed protein,which was renatured and purified, had immuno-reactivity to anti-AS and anti-ES in Western blotting and angiogenesis inhibition activity.

CNHK200-hA-a gene-viral therapeutic system and its antitumor effect on lung cancer / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To develop a novel vector system, which combines the advantages of the gene therapy, antiangiogenic therapy and virus therapy, and to observe its effect on lung cancer.</p><p><b>METHODS</b>Human angiostatin gene hA(k1-5) was inserted into the genome of the replicative virus specific for the tumor cells by virus recombination technology. The expression of hA(k1-5), its effect on tumor growth in vitro and in vivo were studied.</p><p><b>RESULTS</b>A new kind of gene-viral vector system, designated as CNHK200-hA(k1-5), in which the E1b55 000 gene was deleted but the E1a gene of adenovirus preserved, was constructed. The novel vector system possessed the same property as the replicative virus ONYX-015, which replicates in p53- tumor cells but not in normal cells, thus specifically kills tumor cells. In vitro, CNHK200-hA and Ad-hA both could kill A549 tumor cells but the latter needed 100 times more MOI to achieve the same amplitude of cell killing. In vivo, the therapeutic effect of CNHK200-hA on human lung cancer A549 xenograft in nude mice was significantly better than that of Ad-hA and that of tumor-replicative virus ONYX-015.</p><p><b>CONCLUSION</b>CNHK200-hA(k1-5), a novel vector is constructed in which the angiostatin gene is inserted into the genome of the replicative adenovirus cytotoxic to p53-negative tumor cells. It has the advantages of specific tumor targeting, high level gene expression in tumor cells, and potent tumoricidal activity.</p>

The Role of Angiostatin, Vascular Endothelial Growth Factor, Matrix Metalloproteinase 9 and 12 in the Angiogenesis of Hepatocellular Carcinoma / 대한간학회지

BACKGROUND/AIMS: Tumor angiogenesis, a major requirement for tumor growth and metastasis, is regulated by pro- and anti-angiogenic factors. Hepatocellular carcinoma (HCC) has become a common malignant tumor worldwide. It is characterized by a high vascularity. METHODS: We studied the immunohistochemical expression of angiostatin, vascular endothelial cell growth factor (VEGF), matrix metalloproteinase (MMP)-9 and MMP-12, and the relationship between these results and the microvessel density (MVD) in 48 HCC specimens. To determine whether HCC cells express angiostatin per se, we examined the expression of angiostatin, MMP-9 and MMP-12 by Western blotting in four HCC cell lines. RESULTS: Expression of angiostatin and MMP-12 (but not MMP-9) were strongly correlated with decreased MVD in HCCs (P=0.006, P=0.038, respectively). VEGF positive tumors showed a significantly higher MVD than VEGF negative tumors (P=0.01). We divided the 48 cases into the following four groups: group A, angiostatin (+), MMP-9 or -12 (+), and VEGF (-); group B, angiostatin (-) and VEGF (-); group C, angiostatin (+), MMP-9 or -12 (+), and VEGF (+); group D, angiostatin (-) and VEGF (+). There was a significant correlation with MVD among these groups (P<0.001). Angiostatin was detected by Western blotting in 2 out of 4 HCC cell lines and was associated with plasminogen and MMP expression. CONCLUSIONS: These results indicate that angiogenesis in HCC is a complex process involving multiple factors including angiostatin, VEGF, and MMP. Our results suggest that angiostatin is generated by MMP-mediated proteolysis of plasminogen in HCC cells.

The study of biological properties of gliomas / 中国医学科学院学报

In order to explore the new methods of biological treatment of human gliomas, this project is to study the biological properties of gliomas from four different aspects, the results show that there is a IL-6 autocrine loop in human gliomas and the growth of gliomas will be inhibited when the autocrine loop is broken. There is a magnificent predominant expression of Th2 cytokines in human gliomas and human glioma cells, the switching of Th2 to Th1 can inhibit the proliferation of glioma cells. The dosage of 100 micrograms/ml of erythromycin is the best of therapeutic effect. Angiostatin can not only inhibit the vascular endothelial growth, but also have the inhibitory role on the growth of glioma cells in vivo. The above studies have provided some new ideas and will be very helpful for the treatment of glioma patients.

Feeding of mixed-carbon-resource during the expression phase in cultivation of recombinant Pichia pastoris expressing angiostatin / 生物工程学报

A recombinant strain of Pichia pastoris with a phenotype of Muts was used to produce angiostatin in a 5-L fermentor. The methanol utilization ability of the present strain was weak, which resulted in extremely low growth rate and angiostatin productivity during the expression phase with methanol as the sole carbon source. To enhance the cell density and angiostatin expression level, mixed-carbon-source of glycerol-methanol was used in the expression phase. The methanol concentration was well controlled at 5 g/L by a methanol sensor and control system, and glycerol was continuously fed into the fermentor to achieve a higher cell density. 120 g/L of cells and 39 mg/L of angiostatin were reached at the end of fermentation which lasted 110 h. The mean specific cell growth rate in the expression phase was 0.01 h(-1), and the mean specific angiostatin productivity was 0.006 mg/(g x h). According to the data obtained in several runs of fermentation in which glycerol was fed at different rates, a higher mean specific angiostatin productivity was reached at the mean specific cell growth rate of 0.012 h(-1). To avoid the repression of angiostatin expression caused by residual glycerol and ethanol accumulation due to overfeeding of glycerol, glycerol addition was controlled to produce continuous oscillations in dissolved oxygen, because the change of dissolved oxygen concentration could deliver the information of available carbon source in the fermentation broth. Controlled glycerol feeding also avoided the problem of oxygen limitation brought by high cell density, and thus decreased the cooling requirement of the fermentor. Cell density reached 150 g/L at the end of fermentation, and angiostatin level reached 108 mg/L after an expression period of 96 h when the mean specific growth rate was maintained at 0.012 h(-1) by using the glycerol feeding strategy to result in the oscillations in dissolved oxygen. The mean specific angiostatin productivity was improved to 0.02 mg/(g x h). The apparent cell yield on glycerol and methanol were respectively 0.69 g/g and 0.93 g/g, higher than those in the fermentation without using the feeding strategy with dissolved oxygen as the indicator of metabolism.

Inhibitory effects of murine angiostatin on implant carcinoma of nude mouse / 中华外科杂志

<p><b>OBJECTIVE</b>To study the effects of murine angiostatin, which was transfected into the human hepatocellular cancer cell line SMMC-7721, on the implant carcinoma of nude mouse.</p><p><b>METHODS</b>The human hepatocellular cancer cell line SMMC-7721, which could express murine angiostatin gene stably, was constructed. The animals were divided into three groups: SMMC-7721 cell was implanted into control group, SMMC-7721/pcDNA3.1 (+) cell was implanted into vector group, and SMMC-7721/pcDNA3.1-mAST cell was implanted into angiostatin group. The carcinoma volume, weight, and microvessel density (MVD) of each group were compared.</p><p><b>RESULTS</b>The implant carcinoma volume in 35 days was (3 538.1 +/- 643.3) mm(3), (3 128.5 +/- 546.6) mm(3), and (755.8 +/- 198.2) mm(3) in the control group, vector group, and angiostatin group. The carcinoma weight of the control group, vector group, and angiostatin group was (6.0 +/- 0.7) g, (5.9 +/- 0.5) g, (2.1 +/- 0.5) g, respectively. The carcinoma MVD was 52.2 +/- 6.6, 49.4 +/- 7.0, and 25.5 +/- 4.1 accordingly. The carcinoma volume, weight, and MVD of the angiostatin group were significantly smaller than those of the control group and vector group (P < 0.01). The inhibitory rate of carcinoma reached 78.6%.</p><p><b>CONCLUSIONS</b>Nude mouse experiments showed that the tumorigenic capacity of cells transfected had been reduced greatly, and that the carcinoma volume, weight and MVD were significantly lower than those of the control group. We conclude that angiostatin inhibits the growth of carcinoma by its inhibition of carcinoma angiogenesis.</p>

Expression of Angiostatin Using DNA-Based Semliki Forest Virus Replicon

Angiogenesis is recognized as a critical factor in the growth of tumor cells and plays a key role in the tumor metastasis. Recent studies for antiangiogenic substances are getting popular. The angiostatin, one of the antiangiogenic substances, leads to the increased apoptosis of the tumor cells by inhibiting the neovascularization of the tumor. The angiostatin was identified as the internal fragments of the plasminogen which has no antiangiogenic activity. By hydrolysis of the plasminogen, the angiostatin can be produced. In this study, we constructed the SFV-derived DNA vector by employing the cytomegalovirus immediate early enhancer/ promoter (CMV). This vector makes it possible to transfect the cells with DNA without the in vitro transcription process. The C-myc epitope and polyhistidine residue sequences were placed in downstream of the angiostatin gene to make it eligible to detect the expressed protein. The murine Ig kappa-chain V-J2-C signal sequence was placed in upstream to secrete the expressed protein from the cells. We confirmed the expression of angiostatin in the BHK-21 cells using DNA-based SFV replicon.

Inhibition Effect of Angiostatin and Endostatin on Human Angiogenesis

PURPOSE: Angiogenesis is a critical determinant of tumor growth and the development of metastasis. Angiostatin and endostatin have been used in a variety of in vitro and in vivo animal models as effective inhibitors of angiogenesis. However, human angiostatin and endostatin have not been tested against an intact human tissue target in vitro to determine its ability to achieve an antiangiogenic response. We performed our study to determine if human angiostatin and endostatin would inhibit the development of an angiogenic response (initiation) and to determine the subsequent growth (angiogenic index) of human vessels in a dose-dependent manner with a human placental vein angiogenesis model (HPVAM). METHODS: We used full thickness human placental vein discs cultured in three-dimensional fibrin-thrombin clots with an overlay of liquid media. Human angiostatin and endostatin were evaluated in concentrations ranging from 10-9 M to 10-4 M. A positive control containing 20% fetal bovine serum and a negative control using heparin and hydrocortisone 21-phosphate were also tested. RESULTS: Human angiostatin did not inhibit the initiation of an angiogenic response and the subsequent development of the angiogenic response (angiogenic index) at any concentration. Human endostatin significantly inhibited the initiation rate of an angiogenic response at a concentration of 10-4 M (p<0.001) and the subsequent development of an angiogenic response (angiogenic index) from a concentrations of 10-5 M to 10-4 M (p<0.001, p<0.001, respectively). CONCLUSION: We conclude that a very high concentration of human endostatin can inhibit the angiogenic response in human vascular tissue and that human angiostatin will not inhibit angiogenesis of normal human blood vessels in vitroThese results suggest that human endostatin has a more powerful antiangiogenic effect than human angiostatin, but we need further investigations of human angiostatin against an intact human tissue target.

cDNA Cloning and Expression of Angiostatin, an Angiogenesis Inhibitor , from Human Liver Tissue mRNA / 대한암학회지

PURPOSE: Angiostatin, a 38 kDa internal fragment of plasminogen, is a potent inhibitor of angiogenesis. It blocks neovascularization and growth of primary and metastatic tumors in mice. To produce recombinant angiostatin protem comprising kringle 1-4 of plasminogen, we cloned the angiostatin cDNA from human liver tissue mRNA and expressed it in E. coli. MATERIALS AND METHODS: We cloned angiostatin cDNA from human liver tissue mRNA using reverse transcriptase polymerase chain reaction (RT-PCR) method. Cloned cDNA was ligated to pET22b (+) expression vector, transformed into E. coli stram BL21 (DE3) and expressed by IPTG induction. Recombinant human angiostatin protein was purified from the inclusion bodies of lysated bacterial pellet with 8 M urea solubilization, refolding, single step Lysine-Sepharose 4B affinity chromatography and 0.2 M E-aminocarproic acid elution. The anti-angiogenic activity of purified recombinant angiostatin was assayed with endothelial cell proliferation assay and chorioallantoic membrane assay (CAM). RESULTS: The identification of cloned angiostatin cDNA was confirmed by Southern hybridization and Pst I restriction enzyme digestion pattern. Angiostatin cDNA was expressed in E. coli, refolded in vitro and purified by Lysine Sepharose 4B affinity chromatography. The molecular weight of purified recombinant angiostatin was about 55 kDa on the SDS-PAGE. It inhibited the proliferation of bovine capillary endothelial (BCE) cells in vitro with a half-maximal inhibition concentration (ED50) of approximately 500 ng/mL. It also suppressed neovasculrization on the CAM assay. CONCLUSION: These results demonstrated that recombinant human angiostatin has similar function and biological activity compared with human angiostatin which is purified from porcine elastase digested human plasminogen fragment.