Isolation and Characterization of a Monobody with a Fibronectin Domain III Scaffold That Specifically Binds EphA2.

Autor: Seung-Hwan Park, Sukho Park, Dong-Yeon Kim, Ayoung Pyo, Richard H Kimura, Ataya Sathirachinda, Hyon E Choy, Jung-Joon Min, Sanjiv Sam Gambhir, Yeongjin Hong
Jazyk: angličtina
Rok vydání: 2015
Předmět:
Zdroj: PLoS ONE, Vol 10, Iss 7, p e0132976 (2015)
Druh dokumentu: article
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0132976
Popis: Monobodies are binding scaffold proteins originating from a human fibronectin domain III (Fn3) scaffold that can be easily engineered with specificity and affinity. Human EphA2 (hEphA2) is an early detection marker protein for various tumors including lung, breast, and colon cancer. In this study, we isolated two hEphA2-specific monobodies (E1 and E10) by screening a yeast surface display library. They showed the same amino acid sequence except in the DE loop and had high affinity (~2 nM Kd) against hEphA2. E1 bound only hEphA2 and mEphA2, although it bound hEphA2 with an affinity 2-fold higher than that of mEphA2. However, E10 also bound the mEphA6 and mEphA8 homologs as well as hEphA2 and mEphA2. Thus, E1 but not E10 was highly specific for hEphA2. E1 specifically bound human cells and xenograft tumor tissues expressing hEphA on the cell surface. In vivo optical imaging showed strong targeting of Cy5.5-labeled E1 to mouse tumor tissue induced by PC3 cells, a human prostate cancer cell line that expresses a high level of hEphA2. In conclusion, the highly specific monobody E1 is useful as a hEphA2 probe candidate for in vivo diagnosis and therapy.
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