title: Fusion protein based on Grb2-SH2 domain for cancer therapy.
abstract: Epidermal growth factor receptor (EGFR) is one of the very attractive targets for cancer therapy. In this study, we generated fusion proteins containing one or two Src-homology 2 (SH2) domains of growth factor receptor bound protein 2 (Grb2), which bind to phosphorylated EGFR, added with HIV-1 transactivating transcription for cell membrane penetration (termed TSF and TSSF, respectively). We examined if they can interfere Grb2-mediated signaling pathway and suppress tumor growth as expected from the lack of SH3 domain, which is necessary to intermediate EGFR-Grb2 cell signaling, in the fusion proteins. The transduction efficiency of TSSF was similar to that of TSF, but the binding activity of TSSF to EGFR was higher than that of TSF. Treatment of EGFR-overexpressing cells showed that TSSF decreased p42-ERK phosphorylation, while TSF did not. Both the proteins delayed cell growth but did not induce cell death in culture. TSSF also significantly suppressed tumor growth in vivo under consecutive administration. In conclusion, TSSF showed an ability to inhibit EGFR-Grb2 signaling and could have a potential to treat EGFR-activated cancer.
authors.affiliation: Molecular Imaging Center, National Institute of Radiological Sciences, Japan.
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Saito
authors.forename: Takako
authors.initials: T
authors.lastname: Furukawa
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Arano
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Fujibayashi
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Saga
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D051380:GRB2 Adaptor Protein / Q000235:genetics / Q000627:therapeutic use*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D009369:Neoplasms / Q000188:drug therapy* / Q000473:pathology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000627:therapeutic use*; D018909:src Homology Domains
chemical_list: D051380:GRB2 Adaptor Protein; D011993:Recombinant Fusion Proteins