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Benelli R, Morini M, Brigati C, Noonan DM, Albini A. Angiostatin inhibits extracellular HIV-Tat-induced inflammatory angiogenesis. Int J Oncol 2003; 22:87-91. [PMID: 12469189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023] Open
Abstract
The HIV-Tat protein can be released extracellularly where it is able to recruit leukocytes and induce angiogenesis. These activities are mediated by the direct interaction of Tat with VEGFR2 on endothelial cells and chemokine receptors on leukocytes. We have recently shown that angiostatin, an anti-angiogenic peptide fragment of plasminogen, is able to inhibit the recruitment of neutrophils induced by bacterial fMLP and alpha chemokines both in vitro and in vivo. In vivo this was associated with an inhibition of the angiogenic response by angiostatin. These observations suggested that angiostatin could be a suitable inhibitor of Tat-induced angiogenesis, as it acts on both endothelial and neutrophil at the same time. In vitro, chemotaxis assays demonstrated that angiostatin inhibited Tat-induced chemotaxis of neutrophils with an inverse bell shaped profile. In vivo the injection of matrigel plugs containing Tat or its chemokine-like peptide (CysL24-51) caused the infiltration of neutrophils and a strong angiogenic response. Angiostatin completely blocked this inflammatory response, inhibiting the recruitment of inflammatory and endothelial cells inside the implant. Taken together, these results indicate that angiostatin can act as an inhibitor of both endothelial and neutrophil recruitment. As these cell types are also the targets of extracellularly released Tat, angiostatin could be used to contrast Tat-associated vasculopathies.
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Abstract
Angiogenesis is required for invasive tumor growth and metastasis and constitutes an important point in the control of cancer progression. Its inhibition may be a valuable new approach to cancer therapy. Avascular tumors are severely restricted in their growth potential because of the lack of a blood supply. For tumors to develop in size and metastatic potential they must make an "angiogenic switch" through perturbing the local balance of proangiogenic and antiangiogenic factors. Frequently, tumors overexpress proangiogenic factors, such as vascular endothelial growth factor, allowing them to make this angiogenic switch. Two strategies used in the development of antiangiogenic agents involve the inhibition of proangiogenic factors (eg, anti-vascular endothelial growth factor monoclonal antibodies) as well as therapy with endogenous inhibitors of angiogenesis, such as endostatin and angiostatin. Therapy with endogenous angiogenic inhibitors such as endostatin and angiostatin may reverse the angiogenic switch preventing growth of tumor vasculature. Preclinical studies have shown that endostatin effectively inhibits tumor growth and shrinks existing tumor blood vessels. Phase 1 clinical trials of endostatin and angiostatin are ongoing, and preliminary results show minimal toxicities.
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Li M, Huang X, Zhu Z, Zhao Q, Wong M, Gorelik E. The therapeutic efficacy of angiostatin against weakly- and highly-immunogenic 3LL tumors. In Vivo 2002; 16:577-82. [PMID: 12494903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
BACKGROUND Antiagiogenesis represents a promising approach to cancer therapy. We have previously demonstrated that the antitumor effects of endostatin, one of the most potent angiostatic agents, could be enhanced when combined with immunotherapy. Our current study evaluated whether anti-tumor immune response could also potentiate the therapuetic efficacy of another antiangiogenic drug, angiostatin. METHODS AND RESULTS Using Matrigel assay, we showed that our preparation of recombinant angiostatin possessed potent anti-angiogenic activity in vivo. The antitumor effects of recombinant angiostatin were tested against weakly-immunogenic 3LL Lewis lung carcinoma versus its highly immunogenic variant 3LL-C75. We showed that angiostatin inhibited the growth of 3LL-C75 more potently than that of 3LL tumor, suggesting that the host's immune response potentiates the antitumor effects of angiostatin. This conclusion was further supported by the finding that the antitumor activity of angiostatin against 3LL-C75 tumor was lower in immunodeficient nude mice in comparison with immunocompetent mice. Immunization of C57BL/6 mice with 3LL-C75 cells stimulated the antitumor immunity and inhibited the growth of parental 3LL tumor. Angiostatin treatment of immunized mice further enhanced the antitumor effect of tumor vaccination. CONCLUSION Antitumor immune response could complement the therapeutic efficacy of angiostatin.
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Dabrosin C, Gyorffy S, Margetts P, Ross C, Gauldie J. Therapeutic effect of angiostatin gene transfer in a murine model of endometriosis. THE AMERICAN JOURNAL OF PATHOLOGY 2002; 161:909-18. [PMID: 12213719 PMCID: PMC1867254 DOI: 10.1016/s0002-9440(10)64251-4] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Endometriosis, the growth of ectopic endometrial tissue, is a chronic recurrent disease affecting 10% of the female population causing dyspareunia, pelvic pain, dysmenorrhea, and infertility. Suppression of ovarian activity is the cornerstone of medical therapy with limited benefit and severe adverse effects. Angiogenesis plays a major role in the development of endometriosis suggesting that anti-angiogenic therapy would offer a new therapeutic approach. We report successful treatment of endometriosis in estrogen-supplemented ovariectomized mice by transient overexpression (6 to 10 days of duration) of the gene for a natural angiogenesis inhibitor angiostatin, delivered to the peritoneum by a replication-deficient adenovirus vector (AdAngiostatin). Established endometriosis was eradicated in 14 of 14 AdAngiostatin-treated animals, whereas 11 of 13 control animals showed full disease development. Administered to normal cycling mice for the same transient period, AdAngiostatin caused impaired ovarian function with suppressed corpus luteum development, decreased production of estradiol and progesterone, decreased ovarian and uterine weight, and increased body weight. AdAngiostatin treatment lowered the levels of sex steroids but did not induce total castration. Gene therapy with angiogenic inhibitors is a highly effective treatment for endometriosis, even in a host with preserved estrogen levels. However, local or targeted delivery of the gene must be considered to avoid prolonged systemic effects and impaired ovarian function.
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Ambati BK, Joussen AM, Ambati J, Moromizato Y, Guha C, Javaherian K, Gillies S, O'Reilly MS, Adamis AP. Angiostatin inhibits and regresses corneal neovascularization. ARCHIVES OF OPHTHALMOLOGY (CHICAGO, ILL. : 1960) 2002; 120:1063-8. [PMID: 12149060 DOI: 10.1001/archopht.120.8.1063] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
OBJECTIVE To determine the ability of angiostatin and the angiostatin-producing low-metastatic (LM) clone of Lewis lung carcinoma (LLC) to inhibit and regress corneal neovascularization, as compared with the non-angiostatin-producing high-metastatic (HM) clone. METHODS Three groups of C57BL6/J mice underwent chemical and mechanical denudation of corneal and limbal epithelium. One group remained tumor free while the other 2 were implanted with LLC cells (either the HM or LM clones) subcutaneously the day before, 2 weeks after, or 4 weeks after denudation. Corneas were harvested 2 weeks after tumor implantation (at 2, 4, and 6 weeks after denudation for tumor-free mice). Neovascularization was quantified by CD31 immunostaining. In a second experiment, recombinant angiostatin was delivered continuously for 2 weeks via an osmotic pump in mice with established corneal neovascularization. RESULTS The mean percentages of neovascularized corneal area in mice 2 weeks after LM-LLC implantation were 4.6%, 3.7%, and 37.0%, at 2, 4, and 6 weeks after scraping, respectively. In contrast, in the mice implanted with HM-LLC, the corresponding values were 45.4% (P =.01), 90.1% (P =.03), and 80.3% (P =.005). For tumor-free mice, the corresponding values were 62.0% (P =.003), 68.9% (P =.03), and 59.3% (P =.06). Mice implanted with angiostatin pumps had a 37.7% neovascularized corneal area 2 weeks after implantation and 4 weeks after scraping while mice implanted with sham pumps had 60.5% (P =.007). CONCLUSION Angiostatin inhibits and regresses corneal neovascularization induced by mechanical and alkali corneal injury. CLINICAL RELEVANCE This appears to be the first evidence of biologically induced regression of corneal neovascularization, and the first direct demonstration of angiostatin-induced regression of neovascularization in any tissue.
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Murota SI. [Opening to the age of regenerative medicine--the mechanism of angiogenesis]. KOKUBYO GAKKAI ZASSHI. THE JOURNAL OF THE STOMATOLOGICAL SOCIETY, JAPAN 2002; 69:81-8. [PMID: 12136664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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Watts P, Suresh P, Mezer E, Ells A, Albisetti M, Bajzar L, Marzinotto V, Andrew M, Massicotle P, Rootman D. Effective treatment of ligneous conjunctivitis with topical plasminogen. Am J Ophthalmol 2002; 133:451-5. [PMID: 11931777 DOI: 10.1016/s0002-9394(01)01433-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE The etiology of ligneous conjunctivitis is now known to be due to an underlying type 1 plasminogen deficiency. We hereby report the clinical features of three cases and their response to topically administered plasminogen. DESIGN Observational case series. METHODS Two Caucasian females aged 5 years and an 18-month male of north African descent presented with a membranous conjunctivitis, which recurred after surgical excision. Case 1 presented before the association with plasminogen deficiency was known with a bilateral chronic membranous mucopurulent conjunctivitis from the age of 14 months associated with bronchiolitis and gingival hyperplasia. A diagnosis of ligneous conjunctivitis was entertained and a number of drops were instituted. At the age of 4 years plasminogen levels were ordered. Case 2 presented at the age of 4 years with a unilateral chronic membranous conjunctivitis. Plasminogen levels were requested as soon as a diagnosis of ligneous conjunctivitis was suspected. Case 3 was born with congenital hydrocephalus. Conjunctivitis was treated with antibiotics from the age of 1 month. He presented to the eye clinic at the age of 5 months when a clinical diagnosis of ligneous conjunctivitis was entertained and treated with a number of medications. Plasminogen levels were available at 9 months of age. RESULTS The two female patients returned plasminogen levels of 0.25 U/ml and 0.3 U/ml, well below the normal level of 0.7-1.0 U/ml. Functional plasminogen levels in the male infant were not recordable with plasminogen antigen levels of 0.125 U/ml (normal range, 0.52-1.82). All cases have responded well to excision of the membranes and institution of topical plasminogen drops. There has been no recurrence with more than 12 months' follow-up. CONCLUSIONS With the knowledge of the etiology of ligneous conjunctivitis, efforts are underway to identify the best method of delivery of plasminogen. Topical plasminogen concentrate from fresh frozen plasma holds promise as the definitive treatment for this chronic membranous conjunctivitis
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van Dam FSAM, Renckens CNM. [Information about cancer treatment and the media]. NEDERLANDS TIJDSCHRIFT VOOR GENEESKUNDE 2002; 146:524-5. [PMID: 11925804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
A 'hopeful' development in cancer treatment (angiostatin) was reported in the Dutch press, which led to considerable disquiet amongst patients. There were no scientific articles that warranted this press publication. It has previously been stated that it is unethical for medical researchers to inform the press about treatments which have not been scrutinized by the medical community. The press on the other hand, should maintain a more responsible attitude toward medical claims and double-check medical information, even when it comes from renowned medical researchers. The main distinction between mainstream medicine and medical quackery is that the former is based on the results of controlled published research. When physicians propagate results in the popular press that have not been critically evaluated by the medical community, the distinction between quackery and mainstream medicine is undermined.
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Abstract
Ovarian cancer claims the lives of more women in North America each year than all other gynecologic malignancies combined. Despite the high initial response rates of patients with advanced ovarian cancer to aggressive primary surgical debulking followed by combination chemotherapy, the majority of patients will ultimately develop disease recurrence. The high risk of relapse and nearly guaranteed incurability after relapse is due to genetic instability and a high mutation rate of neoplastic cells that together allow for a high risk of selection for drug resistance. Given the seemingly insurmountable obstacle that acquired drug resistance presents in a setting of minimal, often undetectable, residual tumor burden in women with ovarian cancer, antiangiogenic-targeted therapies offer an attractive strategy for enhanced long-term disease-free survival. The past decade has witnessed a substantial proliferation in our knowledge regarding tumor angiogenesis, which has spurred interest in antiangiogenesis drug development. Current clinical trials are evaluating these agents in a variety of solid tumors, including ovarian cancer. Preliminary work has provided hope that the addition of antiangiogenic therapies may be incorporated into the treatment of women afflicted with ovarian cancer and may translate into enhanced survival.
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Margetts PJ, Gyorffy S, Kolb M, Yu L, Hoff CM, Holmes CJ, Gauldie J. Antiangiogenic and antifibrotic gene therapy in a chronic infusion model of peritoneal dialysis in rats. J Am Soc Nephrol 2002; 13:721-728. [PMID: 11856777 DOI: 10.1681/asn.v133721] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
To identify the relative importance of peritoneal fibrosis and angiogenesis in peritoneal membrane dysfunction, adenoviral mediated gene transfer of angiostatin, a recognized angiogenesis inhibitor, and decorin, a transforming growth factor-beta-inhibiting proteoglycan, were used in a daily infusion model of peritoneal dialysis. A peritoneal catheter and subcutaneous port were inserted in rats. Five and fourteen d after insertion, adenovirus-expressing angiostatin, decorin, or AdDL70, a null control virus, were administered. Daily infusion of 4.25% Baxter Dianeal was initiated 7 d after catheter insertion and continued until day 35. Three initial doses of lipopolysaccharide were administered on days 8, 10, and 12 to promote an inflammatory response. Net ultrafiltration was used as a measure of membrane function, and peritoneum-associated vasculature and mesenteric collagen content was quantified. Ultrafiltration dysfunction, angiogenesis, and fibrosis were observed in daily infusion control animals. Animals treated with AdAngiostatin demonstrated an improvement in net ultrafiltration (-3.1 versus -7.8 ml for control animals; P = 0.0004) with a significant reduction in vessel density. AdDecorin-treated animals showed a reduction in mesenteric collagen content (1.8 versus 2.9 microg/mg; P = 0.04); however, AdDecorin treatment had no effect on net ultrafiltration. In a rodent model of peritoneal membrane failure, net ultrafiltration was significantly improved and peritoneal-associated blood vessels were significantly reduced by using adenovirus-mediated gene transfer of angiostatin. Decorin, a transforming growth factor-beta-inhibiting proteoglycan, reduced collagen content but did not affect net ultrafiltration. Improvement in the function of the peritoneum as a dialysis membrane after treatment with angiostatin has implications for treatment of peritoneal membrane dysfunction seen in patients on long-term dialysis.
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Uthman I, Al-Kutoubi A, Sawaya J. Recurrent venous thrombosis in Behçet's disease: successful endovascular treatment with thrombolysis and stent. Clin Rheumatol 2002; 20:267-9. [PMID: 11529634 DOI: 10.1007/pl00011202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We report the case of a patient with Behçet's disease (BD) and recurrent venous thrombosis in the right subclavian vein, successfully treated with balloon dilatation and the insertion of a Wallstent. Subsequent follow up at 6 months showed no evidence of reocclusion. Endovascular stents should be considered as a possible interventional modality in BD patients with aneurysms or recurrent venous or arterial thrombosis.
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Ma HI, Lin SZ, Chiang YH, Li J, Chen SL, Tsao YP, Xiao X. Intratumoral gene therapy of malignant brain tumor in a rat model with angiostatin delivered by adeno-associated viral (AAV) vector. Gene Ther 2002; 9:2-11. [PMID: 11850717 DOI: 10.1038/sj.gt.3301616] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2001] [Accepted: 10/11/2001] [Indexed: 01/29/2023]
Abstract
We have utilized a recombinant adeno-associated viral (AAV) vector carrying the angiostatin gene as an anti-angiogenesis strategy to treat the malignant brain tumor in a C6 glioma/Wistar rat model. Angiostatin, as a potent angiogenesis inhibitor, shows high promises as an anti-cancer drug through the inhibition of tumor neovessel formation. However, sustained in vivo protein delivery is required to achieve the therapeutic effects. The AAV vector has been proven to be able to deliver sustained and high-level gene expression in vivo, and therefore, is well suited to such a purpose. In this study, we implanted 5 x 10(5) C6 glioma cells into the rat brain 7 days before gene therapy. Intratumoral injection of a high-titer AAV-angiostatin vector has rendered efficacious tumor suppression and resulted in long-term survival in 40% of the treated rats, whereas the control AAV-GFP vector did not have any therapeutic benefits. In addition, we have investigated the combined gene therapy of an adenoviral vector carrying the suicidal thymidine kinase gene along with the AAV-angiostatin vector. The combined therapy offered the best tumor-suppressive effects and increased long-term survival to 55% in the treated rats. Our study has demonstrated the potential of using AAV as a safe and effective vector for anti-angiogenic gene therapy of brain tumors.
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Hori T, Ido A, Tsubouchi H. [Tumor dormancy therapy for hepatocellular carcinoma]. NIHON RINSHO. JAPANESE JOURNAL OF CLINICAL MEDICINE 2001; 59 Suppl 6:824-8. [PMID: 11762064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
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Riedel F, Hörmann K. [Anti-angiogenesis - a therapy concept in the treatment of head and neck carcinomas? A review]. Laryngorhinootologie 2001; 80:535-41. [PMID: 11555787 DOI: 10.1055/s-2001-17090] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
BACKGROUND Head and neck squamous cell carcinoma (HNSCC) is an aggressive malignancy that is now the sixth most common neoplasm in the world. Despite numerous advances in treatment, the long-term survival has remained the same for the last 25 years. Angiogenesis has been shown to be important for HNSCC tumour growth and metastasis. Therefore, inhibitors of angiogenesis are a new class of anti-neoplastic substances that might be a powerful complement to conventional therapy in HNSCC. MATERIAL AND METHODS The role of angiogenesis in HNSCC as well as preclinical and clinical trials concerning inhibitors of tumor-angiogenesis are discussed here. RESULTS Many of the investigated angiogenesis inhibitors demonstrated anti-tumor effects in preclinical and clinical trials. In a few cases, partial remission was observed. CONCLUSIONS Anti-angiogenic therapy will undoubtly have the potential to change standard tumor therapies. Some anti-angiogenic substances appear to be promising candidates for a clinical use in the therapy of HNSCC.
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Fan X, Guo X, Han B. [Vascular growth and non-small cell lung cancer]. ZHONGHUA JIE HE HE HU XI ZA ZHI = ZHONGHUA JIEHE HE HUXI ZAZHI = CHINESE JOURNAL OF TUBERCULOSIS AND RESPIRATORY DISEASES 2001; 24:499-502. [PMID: 11718044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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Matsumoto G, Ohmi Y, Shindo J. Angiostatin gene therapy inhibits the growth of murine squamous cell carcinoma in vivo. Oral Oncol 2001; 37:369-78. [PMID: 11337270 DOI: 10.1016/s1368-8375(00)00100-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Tumor growth is an angiogenesis-dependent process and therapeutic strategies aimed at inhibiting angiogenesis are theoretically attractive. Angiostatin has been shown to potently inhibit endothelial proliferation in vitro and tumor growth in vivo. We now show that a shift in the balance of tumor angiogenesis by gene transfer of a cDNA coding for mouse angiostatin into mouse squamous cell carcinoma NRS-1 and SCC-VII cells suppresses tumor growth in vivo. The inhibition of an angiostatin-transfected tumor was accompanied by a marked reduction in vascularity and the presence of many apoptotic tumor cells. However, transfected-angiostatin cDNA does not affect the expression of the vascular endothelial growth factor (VEGF) and VEGF-R2 in the vascular endothelium. The inhibition mechanisms of neovascularization may be mediated independent of VEGF:VEGF-R2 complex. Our data may provide a useful approach for human oral cancer therapy by gene therapy with angiostatin.
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MESH Headings
- Angiostatins
- Animals
- Apoptosis/physiology
- Blotting, Northern/methods
- Blotting, Western/methods
- Carcinoma, Squamous Cell/blood supply
- Carcinoma, Squamous Cell/genetics
- Carcinoma, Squamous Cell/therapy
- DNA, Complementary
- Endothelial Growth Factors/metabolism
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Female
- Gene Transfer Techniques
- Genetic Therapy/methods
- Lymphokines/metabolism
- Mice
- Mice, Inbred C3H
- Peptide Fragments/genetics
- Peptide Fragments/therapeutic use
- Plasminogen/genetics
- Plasminogen/therapeutic use
- Platelet Endothelial Cell Adhesion Molecule-1/metabolism
- Polymerase Chain Reaction/methods
- Receptor Protein-Tyrosine Kinases/metabolism
- Receptors, Growth Factor/metabolism
- Receptors, Vascular Endothelial Growth Factor
- Tumor Cells, Cultured
- Vascular Endothelial Growth Factor A
- Vascular Endothelial Growth Factors
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Ono M, Kuwano M. [Tumor angiogenesis and tumor angiogenesis inhibitors]. Gan To Kagaku Ryoho 2001; 28:584-90. [PMID: 11383205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
It is important to survey the molecular targets which are involved in tumor angiogenesis for the development of antiangiogenic agents as one of the cancer therapy. This article is meant to review the recent molecular targets of tumor angiogenesis and the molecular mechanism of antiangiogenic agents in human clinical trials.
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Meneses PI, Hajjar KA, Berns KI, Duvoisin RM. Recombinant angiostatin prevents retinal neovascularization in a murine proliferative retinopathy model. Gene Ther 2001; 8:646-8. [PMID: 11320411 DOI: 10.1038/sj.gt.3301423] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2000] [Accepted: 12/20/2000] [Indexed: 11/08/2022]
Abstract
Retinal neovascularization is central to the pathogenesis of proliferative diabetic retinopathy, the leading cause of blindness among the middle-aged population. Angiostatin, a proteolytic fragment of plasminogen is one of the most promising inhibitors of angiogenesis currently in clinical trials. Here we show that recombinant angiostatin can inhibit retinal neovascularization in a mouse model of proliferative retinopathy. Because proliferative diabetic retinopathy is a recurrent disease, effective therapy will need to be sustained. Recombinant adeno-associated viruses permit long-term expression of transfected genes; however, they can only accommodate a small insert sequence. Thus, we engineered and tested a shortened recombinant angiostatin derivative containing a signal sequence to permit secretion. Recombinant protein was purified from the medium of transfected HEK293 cells and injected subcutaneously into treated animals. The retinal vasculature was analyzed in retinal flat mounts and using immunohistochemically stained sections. Both methods demonstrate that this short, secreted form of angiostatin is effective in reducing the development of blood vessels in a nontumor environment and has therapeutic potential for neovascular retinopathies such as diabetic retinopathy, retinopathy of prematurity, retinal vein occlusion and, possibly, age-related macular degeneration.
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Abstract
The study of angiogenesis, and the promise of angiogenesis inhibition as a means of cancer therapy, has dramatically accelerated in the last several years. The discovery and publication of angiostatin by O'Reilly and colleagues in Judah Folkman's lab in 1994 has greatly contributed to this progress. Angiostatin is a kringle-containing fragment of plasminogen, which is a potent inhibitor of angiogenesis in vivo, and selectively inhibits endothelial cell proliferation and migration in vitro. There have been a number of proposed proteolytic mechanisms by which plasminogen is cleaved to form angiostatin, and the resulting cleavage products contain different NH2 and COOH termini of the angiostatin. Therefore, it is possible that there are more than one angiostatin isoforms (or angiostatin-related proteins) which occur in one or more normal or pathophysiological situations. It is also possible that some of the proteolytic processes which can convert plasminogen to angiostatin-like proteins are simply laboratory artifacts. Angiostatin-related proteins exert potent endothelial cell inhibitory activity, including the induction of apoptosis, and inhibition of migration, and the intact kringle structures are believed to be necessary for the antiangiogenic activity. Efforts are now underway to translate the understanding of the biology of angiostatin to clinical practice, which includes phase 1 clinical trials with recombinant angiostatin K1-3 (kringles 1-3) as well as phase 1 trials of an Angiostatin Cocktail, which induces the direct in vivo conversion of plasminogen to angiostatin 4.5 (kringles 1-4, plus most of kringle 5). The translation of the basic science of angiostatin and angiostatin-related proteins to clinical trial promises to provide an important new tool in the treatment of cancer by inhibition of angiogenesis.
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Abstract
Considerable progress has been made in the understanding of the molecular structure and mechanistic aspects of Angiostatin and Endostatin, endogenous angiogenesis inhibitors that have been shown to regress tumors in murine models. The growing body of literature surrounding these molecules and on the efficacy of these proteins is in part due to the ability to generate these proteins in recombinant systems as well characterized molecules. Recombinant human Angiostatin and Endostatin are in Phase I trials, following the manufacture of clinical grade material at large scale. This review highlights the recent advances made on understanding the structure and function of Angiostatin and Endostatin.
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Lu H, Zhang H, Wang Q, Yuan H, He W, Zhao Z, Li Y. Purification, refolding of hybrid hIFNgamma-kringle 5 expressed in Escherichia coli. Curr Microbiol 2001; 42:211-6. [PMID: 11270657 DOI: 10.1007/s002840010206] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The DNA sequence coding for plasminogen kringle 5 (pK5), an inhibitor of angiogenesis, was fused with that coding for interferon gamma and over-produced in the form of inactive inclusion bodies in E. coli. The amount of fusion protein was about 40% of total protein produced. The fusion protein contained in the inclusion bodies was solubilized in 8 M urea and purified by anion-exchange chromatography. We employed the orthogonal experimental design L16(4(5)) (5 factors, 4 levels, 16 experiments) procedure for researching the influence of denaturant, aggregation suppressor L-arginine, NaCl, pH, and glycine on the refolding procedure. Our results suggest that the presence of appropriate L-arginine, NaCl, and denaturant in the refolding buffer inhibits the aggregation of the fusion protein and increases the yield of renatured protein with biological activity. The refolded fusion protein, gammaIFN/pk5, has in vitro anti-endothelial cell proliferation activity.
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Scappaticci FA, Smith R, Pathak A, Schloss D, Lum B, Cao Y, Johnson F, Engleman EG, Nolan GP. Combination angiostatin and endostatin gene transfer induces synergistic antiangiogenic activity in vitro and antitumor efficacy in leukemia and solid tumors in mice. Mol Ther 2001; 3:186-96. [PMID: 11237675 DOI: 10.1006/mthe.2000.0243] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Angiostatin and endostatin are potent endothelial cell growth inhibitors that have been shown to inhibit angiogenesis in vivo and tumor growth in mice. However, tumor shrinkage requires chronic delivery of large doses of these proteins. Here we report synergistic antitumor activity and survival of animals when these factors are delivered in combination to tumors by retroviral gene transfer. We have demonstrated this efficacy in both murine leukemia and melanoma models. Complete loss of tumorigenicity was seen in 40% of the animals receiving tumors transduced by the combination of angiostatin and endostatin in the leukemia model. The synergy was also demonstrated in vitro on human umbilical vein endothelial cell differentiation and this antiangiogenic activity may suggest a mechanism for the antitumor activity in vivo. These findings imply separate pathways by which angiostatin and endostatin mediate their antiangiogenic effects. Together, these data suggest that a combination of antiangiogenic factors delivered by retroviral gene transfer may produce synergistic antitumor effects in both leukemia and solid tumors, thus avoiding long-term administration of recombinant proteins. The data also suggest that novel combinations of antiangiogenic factors delivered into tumors require further investigation as therapeutic modalities.
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Abstract
The formation of new blood vessels (angiogenesis) is crucial for the growth and persistence of primary solid tumors and their metastases. Furthermore, angiogenesis is also required for metastatic dissemination, since an increase in vascular density will allow easier access of tumor cells to the circulation. Induction of angiogenesis precedes the formation of malignant tumors, and increased vascularization seems to correlate with the invasive properties of tumors and thus with the malignant tumor phenotype. In the last few years, the discovery and characterization of tumor-derived angiogenesis modulators greatly contributed to our understanding of how tumors regulate angiogenesis. However, although angiogenesis appears to be a rate-limiting event in tumor growth and metastatic dissemination, a direct connection between the induction of angiogenesis and the progression to tumor malignancy is less well understood. In this review, we discuss the most recent observations concerning the modulation of angiogenesis and their implications in tumor progression, as well as their potential impact on cancer therapy.
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Bhat V, Jobe AH, Wert S, Jesmok GJ, Ikegami M. Plasminogen did not affect lung function in surfactant-treated preterm lambs. BIOLOGY OF THE NEONATE 2000; 78:212-9. [PMID: 11044771 DOI: 10.1159/000014273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Preterm infants with respiratory distress syndrome develop fibrin-rich hyaline membranes within the alveoli and have depressed fibrinolytic activity, which is thought to be due to a relative deficiency of plasminogen. Local fibrin deposition inhibits surfactant function and amplifies inflammation. We hypothesized that plasminogen administration to surfactant-treated preterm lambs would prevent fibrin-rich hyaline membrane formation, resulting in the amelioration of lung pathology and improved lung function. We randomly treated preterm lambs (gestational age 127-129 days) with either 16 mg of lysine-plasminogen (n = 10) or saline (n = 10), and ventilated them for 5 h. There were no significant differences in physiologic measurements of lung function (ventilation efficiency index, oxygenation index, dynamic compliance, quasi-static pressure volume curve), measures of lung injury (alveolar wash protein content and (125)I-albumin recovery) or surfactant pool size. The degree and extent of bronchiolar erosion and hyaline membrane formation were similar in the two groups. Plasminogen administration did not improve lung function or prevent hyaline membrane formation in surfactant-treated lambs.
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