Abstract
We previously developed the "immunogene" approach toward cancer gene therapy using epidermal growth factor receptor (EGFR)-mediated endocytosis. Here, we describe an improved immunogene system, in which the antigen-binding (Fab) fragments of the monoclonal antibody (Ab) B4G7 against the human EGFR were conjugated with poly-L-lysine to form a gene delivery vehicle (designated Fab "immunoporter"). Within 12 hours, the β-galactosidase (β-gal) gene was transferred via the Fab immunoporter to virtually all of the nuclei of human squamous carcinoma A431 cells that overproduce the EGFR, and the β-gal enzyme activity was detected within 24 hours and retained for more than 3 days. The β-gal gene was not transferred into human and mouse cells that were deficient in EGFRs, but it was delivered if those mouse cells were transformed with human EGFR genes. β-gal gene transfer via the Fab immunoporter was inhibited by pretreatment with excess amounts of the Fab fragment. The transfer efficiency of the β-gal gene to A431 cells via the Fab immunoporter was ∼2%, which is as high as the lipofection method and 20- to 100-fold higher than the whole Ab immunoporter. The transfer of the herpes simplex virus thymidine kinase gene into A431 tumor cells as a form of the thymidine kinase/Fab immunogene was successful, and subsequent treatment with ganciclovir induced remarkable suicide effects which conferred 1000-fold higher drug sensitivity. Thus, the Fab immunogene was substantially improved with regard to the whole Ab immunogene and could be used as a potent gene transfer vehicle for the in vivo targeting of EGFR-hyperproducing tumor cells.
Original language | English |
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Pages (from-to) | 357-364 |
Number of pages | 8 |
Journal | Cancer Gene Therapy |
Volume | 5 |
Issue number | 6 |
Publication status | Published - 1998 |
Keywords
- Anti-epidermal growth factor receptor antibody
- Endocytosis
- Fab
- Immunogene
- Suicide gene
ASJC Scopus subject areas
- Molecular Medicine
- Molecular Biology
- Cancer Research