Abstract:
Epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor
2 (VEGFR2) are receptor tyrosine kinases known to play critical roles in the development
and progression of tumors. Based on the cross-talk between EGFR and VEGFR2 signal
pathways, we designed and produced a bispecific diabody (bDAb) targeting both EGFR and
VEGFR2 simultaneously. The bispecific molecule (EK-02) demonstrated that it could bind to
HUVEC (VEGFR2 high-expressing) and A431 (EGFR overexpressing) cells. Additionally,
similar to the parental antibodies, it was able to inhibit proliferation and migration, and
induced apoptosis in these cells (HUVECs and A431), demonstrating that it had retained the
functional properties of its parental antibodies. Furthermore, the efficacy of EK-02 was eval-
uated using the human colon adenocarcinoma cell line HT29 (VEGFR2 and EGFR coex-
pressing). In vitro assay showed that EK-02 could bind to HT29 cells, restrain cell growth
and migration, and induce apoptosis with enhanced efficacy compared to both parental anti-
bodies. Further, it inhibited the neovascularization and tumor formation on an HT29 cell
bearing chicken chorioallantoic membrane (CAM) tumor model in vivo. In conclusion, these
data suggest that the novel bDAb (EK-02) has antiangiogenesis and antitumor capacity both
in vitro and in vivo, and can possibly be used as cotargeted therapy for the treatment of
C 2016 American Institute of Chemical Engi-
EGFR and VEGFR2 overexpressing tumors. V
neers Biotechnol. Prog., 32:294–302, 2016
Keywords: epidermal growth factor receptor (EGFR), vascular endothelial growth factor
receptor 2 (VEGFR2), bispecific diabody (bDAb), single-chain fragment (scFv), antiangio-
genesis, antitumor
