title: A high-affinity protein binder that blocks the IL-6/STAT3 signaling pathway effectively suppresses non-small cell lung cancer.
abstract: Interleukin-6 (IL-6) is a multifunctional cytokine that regulates immune responses for host defense and tumorigenic process. Upregulation of IL-6 is known to constitutively phosphorylate signal transducer and activator of transcription 3 (STAT3), leading to activation of multiple oncogene pathways and inflammatory cascade. Here, we present the development of a high-affinity protein binder, termed repebody, which effectively suppresses non-small cell lung cancer in vivo by blocking the IL-6/STAT3 signaling. We selected a repebody that prevents human IL-6 (hIL-6) from binding to its receptor by a competitive immunoassay, and modulated its binding affinity for hIL-6 up to a picomolar range by a modular approach that mimics the combinatorial assembly of diverse modules to form antigen-specific receptors in nature. The resulting repebody was highly specific for hIL-6, effectively inhibiting the STAT3 phosphorylation in a dose- and binding affinity-response manner in vitro. The repebody was shown to have a remarkable suppression effect on the growth of tumors and STAT3 phosphorylation in xenograft mice with non-small cell lung cancer by blocking the hIL-6/STAT3 signaling. Structural analysis of the repebody and IL-6 complex revealed that the repebody binds the site 2a of hIL-6, overlapping a number of epitope residues at site 2a with gp130, and consequently causes a steric hindrance to the formation of IL-6/IL-6Rα complex. Our results suggest that high-affinity repebody targeting the IL-6/STAT3 pathway can be developed as therapeutics for non-small cell lung cancer.
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea.
authors.forename: Joong-Jae
authors.initials: JJ
authors.lastname: Lee
authors.affiliation: Division of Magnetic Resonance Research, Korea Basic Science Institute, Cheongwon, Chungbuk, Korea.
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Microbiology, Chungnam National University College of Medicine, Daejeon, Korea; Current address: Department of Molecular and Life Sciences, College of Science and Technology, Hanyang University, Ansan, Korea.
authors.forename: Chul-Su
authors.initials: CS
authors.lastname: Yang
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea.
authors.forename: Hyun-Ho
authors.initials: HH
authors.lastname: Kyeong
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea.
authors.forename: Jung-Min
authors.initials: JM
authors.lastname: Choi
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea.
authors.forename: Da-Eun
authors.initials: DE
authors.lastname: Hwang
authors.affiliation: Department of Microbiology, Chungnam National University College of Medicine, Daejeon, Korea.
authors.forename: Jae-Min
authors.initials: JM
authors.lastname: Yuk
authors.affiliation: Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Korea.
authors.forename: Keunwan
authors.initials: K
authors.lastname: Park
authors.affiliation: Industrial Biotechnology and Bioenergy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea.
authors.forename: Yu Jung
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Industrial Biotechnology and Bioenergy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea.
authors.forename: Seung-Goo
authors.initials: SG
authors.lastname: Lee
authors.affiliation: Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Korea.
authors.forename: Dongsup
authors.initials: D
authors.lastname: Kim
authors.affiliation: Department of Microbiology, Chungnam National University College of Medicine, Daejeon, Korea. Electronic address: hayoungj@cnu.ac.kr.
authors.forename: Eun-Kyeong
authors.initials: EK
authors.lastname: Jo
authors.affiliation: Division of Magnetic Resonance Research, Korea Basic Science Institute, Cheongwon, Chungbuk, Korea. Electronic address: haekap@kbsi.re.kr.
authors.forename: Hae-Kap
authors.initials: HK
authors.lastname: Cheong
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea. Electronic address: hskim76@kaist.ac.kr.
authors.forename: Hak-Sung
authors.initials: HS
authors.lastname: Kim
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy* / Q000378:metabolism; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D015850:Interleukin-6; D050796:STAT3 Transcription Factor