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Updated: Jul 23, 2026
Rat Mesentery Angiogenesis Assay
Published on: June 18, 2011
Evaluation of endostatin antiangiogenesis gene therapy in vitro and in vivo
1Canji Inc., San Diego, California 92121, USA. xiaomei.jin@canji.com@
Abstract:
Progressive growth and metastasis of solid tumors require angiogenesis, or the formation of new blood vessels. Endostatin is a 20-kDa carboxy-terminal fragment of collagen XVIII that has been shown to inhibit endothelial cell proliferation and tumor angiogenesis. Replication-deficient recombinant adenovirus (rAd) vectors were constructed, which encoded secreted forms of human and mouse endostatin (HECB and MECB, respectively), and, as a control, human alkaline phosphatase (APCB). Accumulation of endostatin was demonstrated in supernatants of cultured cells infected with the endostatin rAds. These supernatants disrupted tubule formation, inhibited migration and proliferation, and induced apoptosis in human dermal vascular endothelial cells or human vascular endothelial cells. Endostatin-containing supernatants had no effect on the proliferation of MidT2-1 mouse mammary tumor cells in vitro. A pharmacokinetic study of MECB in immunocompetent FVB mice demonstrated a 10-fold increase of serum endostatin concentrations 3 days after intravenous administration of 1x10(10) particles of this rAd (215-257 ng/mL compared to 12-38 ng/mL in control rAd-treated mice). Intravenous administration of MECB reduced b-FGF stimulated angiogenesis into Matrigel plugs by 38%. Intratumoral MECB inhibited growth of MidT2-1 syngeneic mammary tumors in FVB mice, but had minimal impact on the growth of MDA-MB-231 human breast tumors in SCID mice. Intravenous therapy with MECB also initially inhibited growth of MidT2-1 tumors, but this activity was subsequently blocked by induced anti-rAd antibodies. In summary, endostatin gene therapy effectively suppressed angiogenic processes in vitro and in vivo in several model systems.
Insights
Endostatin gene therapy using recombinant adenovirus vectors effectively inhibited tumor angiogenesis in vitro and in vivo. This approach suppressed endothelial cell proliferation and tumor growth in preclinical models.
Area of Science:
- Oncology
- Gene Therapy
- Vascular Biology
Background:
- Tumor growth and metastasis depend on angiogenesis, the formation of new blood vessels.
- Endostatin, a fragment of collagen XVIII, inhibits endothelial cell proliferation and angiogenesis.
- Recombinant adenovirus (rAd) vectors offer a platform for gene delivery.
Purpose of the Study:
- To evaluate the efficacy of endostatin gene therapy in suppressing tumor angiogenesis and growth.
- To construct and characterize rAd vectors encoding secreted forms of human and mouse endostatin.
- To assess the in vitro and in vivo anti-angiogenic and anti-tumor effects of endostatin gene therapy.
Main Methods:
- Construction of replication-deficient rAd vectors encoding human (HECB) and mouse (MECB) endostatin, and a control (APCB).
- In vitro assessment of endostatin-containing supernatants on endothelial cell functions (tubule formation, migration, proliferation, apoptosis).
- In vivo studies in mice, including pharmacokinetic analysis, Matrigel plug assay for angiogenesis, and evaluation of tumor growth inhibition (syngeneic and xenograft models).
Main Results:
- Endostatin rAds led to accumulation of secreted endostatin, which inhibited endothelial cell proliferation, migration, tubule formation, and induced apoptosis in vitro.
- Intravenous MECB administration increased serum endostatin levels and reduced b-FGF-stimulated angiogenesis in Matrigel plugs by 38%.
- Intratumoral MECB inhibited syngeneic mouse mammary tumor growth but had minimal effect on human breast tumors. Intravenous therapy showed initial inhibition of mouse tumor growth, later blocked by anti-rAd antibodies.
Conclusions:
- Endostatin gene therapy delivered via rAd vectors demonstrates significant potential for suppressing angiogenic processes.
- The study validates endostatin's anti-angiogenic properties and the feasibility of gene therapy for cancer treatment.
- Further research is warranted to overcome challenges like immune responses against vectors for sustained therapeutic effects.
