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CELLULAR AND MOLECULAR
Fusion Protein Induces HER2/neu Signaling and Facilitates Repair of Injured EpitheliaDepartment of Microbiology, Immunology and Molecular Genetics (T.-H.H., S.L.M.) and the Molecular Biology Institute (S.L.M.), University of California, Los Angeles, Los Angeles, California
Tumor necrosis factor (TNF)-
genetically fused to the carboxyl terminus of a single-chain Fv (ScFv) antibody specific for the human HER2/neu (anti-HER2/neu ScFv-TNF-
) forms a homotrimeric structure that retains both TNF-
activity and the ability to bind HER2/neu. In contrast to anti-HER2/neu IgG3, anti-HER2/neu ScFv-TNF-
induces potent HER2/neu signaling, activating the downstream mitogen-activated protein kinase (MAPK) and Akt pathways in SKBR3 cells. Activation of MAPK and Akt by anti-HER2/neu ScFv-TNF-
inhibited the apoptosis of SKBR3 cells induced by actinomycin D. Remarkably, anti-HER2/neu ScFv-TNF-
facilitated the repair of injured epithelia. Accelerated wound healing required binding to HER2/neu but not TNF-
activity since anti-HER2/neu ScFv-TNF-
(S147Y), containing a mutant TNF-
with significantly decreased biological activity, demonstrated equivalent ability to facilitate wound healing and soluble HER2/neu inhibited the effect. These results suggest that trimeric anti-HER2/neu ScFv has the potential to facilitate wound healing. In addition, fusion with TNF-
provides a novel approach to producing polymeric antibodies.
Address correspondence to: Dr. Tzu-Hsuan Huang, Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Box 951489, Los Angeles, CA 90095-1489. E-mail: thhhuang{at}ucla.edu