Transfection with anti-p65 intrabody suppresses invasion and angiogenesis in glioma cells by blocking nuclear factor-kappaB transcriptional activity.
OBJECTIVE
The strategy of intracellular antibodies to neutralize the function of target proteins has been widely developed for cancer research. This study used an intrabody against p65 subunit to prevent nuclear factor kappaB (NF-kappaB) transcriptional activity in glioma cells and to inhibit the expression of its target genes involved in the invasion and angiogenesis of human gliomas.


METHODS
A single-chain fragment of antibody variable region (scFv) against p65 was prepared using phage display technique. We then prepared an anti-p65 intrabody construct (pFv/nu) by cloning the scFv-encoding sequence into the mammalian nuclear-targeting vector, pCMV/myc/nuc.


RESULTS
p65 expression in human glioma cells (U251 and] U87) transfected with pFv/nu was significantly decreased. We showed that NF-kappaB nuclear translocation and its DNA binding activity were blocked via intrabody transfection in electrophoretic mobility shift assays and the inhibition of NF-kappaB activity in nucleus resulted in the decreasing expression and bioactivity of matrix metalloproteinase-9, urokinase-type plasminogen activator receptor, urokinase-type plasminogen activator, and vascular endothelial growth factor. The intrabody transfected glioma cells showed a markedly lower level of invasion in Matrigel invasion assay. The capillary-like structure formation of endothelial cells was also repressed by coculture with the intrabody transfected glioma cells or exposure to their conditional medium. Intrabody transfection neither induced apoptosis nor altered cell proliferation in U251 and U87 cells as compared with the control vector pCMV/nu. After the injection of pFv/nu-transfected glioma cells, preestablished tumors were almost completely regressed when compared with mock, pCMV/nu, and pGFP/nu.


CONCLUSIONS
Blocking NF-kappaB activity via the nuclear intrabody expression might be a potential approach for cancer therapy.
Li
Liang
L
Program of Cancer Biology, Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, Illinois 61605, USA.
Gondi
Christopher S
CS
Dinh
Dzung H
DH
Olivero
William C
WC
Gujrati
Meena
M
Rao
Jasti S
JS
D000595:Amino Acid Sequence; D000906:Antibodies / Q000276:immunology* / Q000378:metabolism; D000918:Antibody Specificity; D001483:Base Sequence; D015153:Blotting, Western; D001932:Brain Neoplasms / Q000276:immunology* / Q000378:metabolism; D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D024202:Electrophoretic Mobility Shift Assay; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D005910:Glioma / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000235:genetics; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000276:immunology; D009361:Neoplasm Invasiveness / Q000517:prevention & control*; D009389:Neovascularization, Pathologic / Q000517:prevention & control*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051996:Transcription Factor RelA / Q000037:antagonists & inhibitors* / Q000276:immunology; D014158:Transcription, Genetic; D014162:Transfection
D000906:Antibodies; D007135:Immunoglobulin Variable Region; D016328:NF-kappa B; C498143:RELA protein, human; D051996:Transcription Factor RelA