title: Suppression of Aggrus/podoplanin-induced platelet aggregation and pulmonary metastasis by a single-chain antibody variable region fragment.
abstract: Almost all highly metastatic tumor cells possess high platelet aggregating abilities, thereby form large tumor cell-platelet aggregates in the microvasculature. Embolization of tumor cells in the microvasculature is considered to be the first step in metastasis to distant organs. We previously identified the platelet aggregation-inducing factor expressed on the surfaces of highly metastatic tumor cells and named as Aggrus. Aggrus was observed to be identical to the marker protein podoplanin (alternative names, T1α, OTS-8, and others). Aggrus is frequently overexpressed in several types of tumors and enhances platelet aggregation by interacting with the platelet receptor C-type lectin-like receptor 2 (CLEC-2). Here, we generated a novel single-chain antibody variable region fragment (scFv) by linking the variable regions of heavy and light chains of the neutralizing anti-human Aggrus monoclonal antibody MS-1 with a flexible peptide linker. Unfortunately, the generated KM10 scFv failed to suppress Aggrus-induced platelet aggregation in vitro. Therefore, we performed phage display screening and finally obtained a high-affinity scFv, K-11. K-11 scFv was able to suppress Aggrus-induced platelet aggregation in vitro. Moreover, K-11 scFv prevented the formation of pulmonary metastasis in vivo. These results suggest that K-11 scFv may be useful as metastasis inhibitory scFv and is expected to aid in the development of preclinical and clinical examinations of Aggrus-targeted cancer therapies.
authors.affiliation: Division of Experimental Chemotherapy, The Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31, Ariake, Koto-ku, Tokyo, 135-8550, Japan; Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa-shi, Chiba, 277-8561, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Miyata
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takagi
authors.forename: Shigeo
authors.initials: S
authors.lastname: Sato
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Morioka
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Shiba
authors.forename: Tamiko
authors.initials: T
authors.lastname: Minamisawa
authors.forename: Miho
authors.initials: M
authors.lastname: Takami
authors.forename: Naoya
authors.initials: N
authors.lastname: Fujita
mesh_terms: D000818:Animals; D058846:Antibodies, Monoclonal, Murine-Derived / Q000276:immunology / Q000494:pharmacology; D016466:CHO Cells; D045744:Cell Line, Tumor; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood* / Q000473:pathology / Q000556:secondary / Q000628:therapy*; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors* / Q000097:blood / Q000276:immunology; D008565:Membrane Proteins / Q000037:antagonists & inhibitors* / Q000097:blood / Q000276:immunology; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009362:Neoplasm Metastasis; D010974:Platelet Aggregation / Q000187:drug effects*; D011817:Rabbits; D057127:Single-Chain Antibodies / Q000276:immunology / Q000494:pharmacology*; D000098853:Podoplanin
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D057127:Single-Chain Antibodies; C117468:PDPN protein, human; D000098853:Podoplanin
keywords: Aggrus/podoplanin; phage display; platelet aggregation; scFv; tumor metastasis