A fibronectin scaffold approach to bispecific inhibitors of epidermal growth factor receptor and insulin-like growth factor-I receptor

作者：Emanuel Stuart L; Engle Linda J; Chao Ginger; Zhu Rong Rong; Cao Carolyn; Lin Zheng; Yamniuk Aaron; Ho**ach Jennifer; Brown Jennifer; Fitzpatrick Elizabeth; Gokemeijer Jochem; Morin Paul; Morse Brent; Carvajal Irvith M; Fabrizio David; Wright Martin C; Das Gupta Ruchira; Gosselin Michael; Cataldo Daniel; Ryseck Rolf P; Doyle Michael L; Wong Tai W; Camphausen Raymond T; Cload Sharon T; Marsh H Nicholas; Gottardis Marco M; Furfine Eric S^*

来源：mAbs, 2011, 3(1): 38-48.

DOI：10.4161/mabs.3.1.14168

• Adnectin
• biologics
• EGFR
• IGF-IR
• bispecific

Engineered domains of human fibronectin (Adnectins (TM)) were used to generate a bispecific Adnectin targeting epidermal growth factor receptor (EGFR) and insulin-like growth factor-I receptor (IGF-IR), two transmembrane receptors that mediate proliferative and survival cell signaling in cancer. Single-domain Adnectins that specifically bind EGFR or IGF-IR were generated using mRNA display with a library containing as many as 10(13) Adnectin variants. mRNA display was also used to optimize lead Adnectin affinities, resulting in clones that inhibited EGFR phosphorylation at 7 to 38 nM compared to 2.6 mu M for the parental clone. Individual optimized Adnectins specific for blocking either EGFR or IGF-IR signaling were engineered into a single protein (El-Tandem Adnectin). The El-Tandems inhibited phosphorylation of EGFR and IGF-IR, induced receptor degradation and inhibited down-stream cell signaling and proliferation of human cancer cell lines (A431, H292, BxPC3 and RH41) with IC(50) values ranging from 0.1 to 113 nM. Although Adnectins bound to EGFR at a site distinct from those of anti-EGFR antibodies cetuximab, panitumumab and nimotuzumab, like the antibodies, the anti-EGFR Adnectins blocked the binding of EGF to EGFR. PEGylated El-Tandem inhibited the growth of both EGFR and IGF-IR driven human tumor xenografts, induced degradation of EGFR and reduced EGFR phosphorylation in tumors. These results demonstrate efficient engineering of bispecific Adnectins with high potency and desired specificity. The bispecificity may improve biological activity compared to monospecific biologics as tumor growth is driven by multiple growth factors. Our results illustrate a technological advancement for constructing multi-specific biologics in cancer therapy.

• 出版日期2011-2