Gene therapy for pancreatic cancer using an adenovirus vector encoding soluble flt-1 vascular endothelial growth factor receptor.
BACKGROUND
Vascular endothelial growth factor (VEGF) plays an important role in tumor angiogenesis. The soluble form of flt-1 VEGF receptor inhibits VEGF activity in a dominant-negative manner.


OBJECTIVE
This study demonstrated the regional tumor suppression effect of adenovirus-mediated soluble flt-1 in human pancreatic cancer cells.


METHODS
The VEGF expression level was examined in nine cell lines. Panc-1 and PK-8 were used as lower- and higher-VEGF-producing cell lines, respectively. The in vitro proliferation of cancer cells infected with adenovirus vectors encoding soluble flt-1 (Adsflt) and control vectors (AdLacZ) was not different. To assess the in vivo tumor growth suppression, cancer cells were inoculated subcutaneously in SCID mice. Adsflt, AdLacZ, or vehicle was injected directly into the tumors. The early process of tumor angiogenesis in a dorsal skinfold chamber was monitored by intravital microscopy.


RESULTS
In both Panc-1 cells and PK-8 cells, the tumor growth of the Adsflt-treated group was significantly suppressed. The microvessel density, revealed by CD31 immunostaining, was also significantly lower in the Adsflt-treated group. Apoptosis index was higher in the Adsflt group. Immunofluorescence staining revealed the expression of VEGF not only in cancer cells but also in tumor stromal cells. Wild-type cells and AdLacZ-infected cells prompted strong tumor angiogenesis, whereas Adsflt-infected cells failed to exert such an effect.


CONCLUSIONS
These results indicate that antiangiogenic gene therapy using soluble flt-1 might be an effective approach for pancreatic cancer treatment.
Hoshida
Tohru
T
Division of Advanced Science and Technology, Tohoku University Graduate School of Medicine, Sendai, Japan.
Sunamura
Makoto
M
Duda
Dan G
DG
Egawa
Shinichi
S
Miyazaki
Shukichi
S
Shineha
Ryuzaburo
R
Hamada
Hirofumi
H
Ohtani
Haruo
H
Satomi
Susumu
S
Matsuno
Seiki
S
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000235:genetics; D001808:Blood Vessels / Q000737:chemistry / Q000473:pathology; D002455:Cell Division / Q000235:genetics; D016228:Endothelial Growth Factors / Q000235:genetics / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D008222:Lymphokines / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D016513:Mice, SCID; D009368:Neoplasm Transplantation; D009389:Neovascularization, Pathologic; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D012867:Skin / Q000098:blood supply; D012884:Skin Window Technique; D012995:Solubility; D014162:Transfection; D014407:Tumor Cells, Cultured; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D042442:Vascular Endothelial Growth Factors; D023041:Xenograft Model Antitumor Assays / Q000379:methods
D016228:Endothelial Growth Factors; D008222:Lymphokines; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011518:Proto-Oncogene Proteins; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D020794:Receptor Protein-Tyrosine Kinases; D040281:Vascular Endothelial Growth Factor Receptor-1