Intratumoral administration of endostatin plasmid inhibits vascular growth and perfusion in MCa-4 murine mammary carcinomas.
Endostatin, a fragment of the COOH-terminal domain of mouse collagen XVIII is a recently demonstrated endogenous inhibitor of tumor angiogenesis and endothelial cell growth. Antiangiogenic therapy with endostatin in animals requires multiple and prolonged administration of the protein. Gene therapy could provide an alternative approach to continuous local delivery of this antiangiogenic factor in vivo. Established MCa-4 murine mammary carcinomas, grown in immunodeficient mice, were treated with intratumoral injection of endostatin plasmid at 7-day intervals. At the time of sacrifice, 14 days after the first injection, endostatin-treated tumor weights were 51% of controls (P < 0.01). Tumor growth inhibition was accompanied by a marked reduction in total vascular density. Specifically, computerized image analysis showed a 18-21% increase in the median distances between tumor cells and both the nearest anatomical (CD31-stained) vessel [48.1 +/- 3.8 versus 38.3 +/- 1.6 microm (P < 0.05)] and the nearest tumor-specific (CD105-stained) vessel [48.5 +/- 1.5 versus 39.8 +/- 1.5 microm (P < 0.01)]. An increased apoptotic index of tumor cells in endostatin-treated tumors [3.2 +/- 0.5% versus 1.9 +/- 0.3% (P < 0.05)] was observed in conjunction with a significant decrease in tumor perfused vessels (DiOC7 staining), and an increase in tumor cell hypoxia (EF5 staining). Hypoxia resulting from endostatin therapy most likely caused a compensatory increase of in situ vascular endothelial growth factor (VEGF) and VEGF receptor mRNA expression. Increased immunoreactivity of endostatin staining in endostatin-treated tumors was also associated with an increased thrombospondin-1 staining [1.12 +/- 0.16 versus 2.44 +/- 0.35]. Our data suggest that intratumoral delivery of the endostatin gene efficiently suppresses murine mammary carcinoma growth and support the potential utility of the endostatin gene for cancer therapy.
Ding
I
I
Departments of Radiation Oncology, University of Rochester School of Medicine, New York 14642, USA.
Sun
J Z
JZ
Fenton
B
B
Liu
W M
WM
Kimsely
P
P
Okunieff
P
P
Min
W
W
D000818:Animals; D015703:Antigens, CD; D003094:Collagen / Q000235:genetics*; D043170:Collagen Type XVIII; D000071063:Endoglin; D043169:Endostatins; D016228:Endothelial Growth Factors / Q000235:genetics; D005260:Female; D005456:Fluorescent Dyes; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D015316:Genetic Therapy; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D015552:Injections, Intralesional; D008222:Lymphokines / Q000235:genetics; D008325:Mammary Neoplasms, Experimental / Q000098:blood supply / Q000473:pathology / Q000628:therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000517:prevention & control*; D010446:Peptide Fragments / Q000235:genetics*; D010957:Plasmids / Q000008:administration & dosage* / Q000235:genetics; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics; D011956:Receptors, Cell Surface; D017978:Receptors, Growth Factor / Q000235:genetics; D040262:Receptors, Vascular Endothelial Growth Factor; D016896:Treatment Outcome; D014407:Tumor Cells, Cultured; D019010:Vascular Cell Adhesion Molecule-1 / Q000032:analysis; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D015703:Antigens, CD; D043170:Collagen Type XVIII; C064206:ENG protein, human; D000071063:Endoglin; D043169:Endostatins; D016228:Endothelial Growth Factors; D005456:Fluorescent Dyes; D008222:Lymphokines; D010446:Peptide Fragments; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D017978:Receptors, Growth Factor; D019010:Vascular Cell Adhesion Molecule-1; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D003094:Collagen; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor