Functional characterization of an scFv-Fc antibody that immunotherapeutically targets the common cancer cell surface proteoglycan CSPG4.
Cell surface chondroitin sulfate proteoglycan 4 (CSPG4) is an attractive target for antibody-based cancer immunotherapy because of its role in tumor cell biology, its high expression on malignant cells including cancer-initiating cells, and its restricted distribution in normal tissues. The clinical use of CSPG4 has been hampered by the lack of a CSPG4-specific chimeric, humanized, or fully human monoclonal antibody. To overcome this limitation, we generated a CSPG4-specific fully human single-chain antibody termed scFv-FcC21 and characterized its specificity and antitumor activity. Viable CSPG4(+) melanoma cells were used in a screen of a human scFv phage display library that included CDR3 engineered to optimize antibody binding sites. The scFv antibody isolated was then recombinantly engineered with a human immunoglobulin G1 Fc region to construct the fully human antibody scFv-FcC21, which recognized tumors of neuroectodermal origin, various types of carcinomas, mesotheliomas, and sarcomas as well as myeloid leukemias. scFv-FcC21 inhibited in vitro growth and migration of tumor cells and in vivo growth of human tumor xenografts. These effects were mediated by inhibition of the activation of extracellular signal-regulated kinase and focal adhesion kinase signaling pathways that are critical for tumor cell growth and migration, respectively. Our findings define the CSPG4-specific fully human scFv-FcC21 antibody as a candidate therapeutic agent to target the many types of tumors that express CSPG4.
University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213, USA.
Xinhui
X
Wang
Akihiro
A
Katayama
Yangyang
Y
Wang
Ling
L
Yu
Elvira
E
Favoino
Koichi
K
Sakakura
Alessandra
A
Favole
Takahiro
T
Tsuchikawa
Susan
S
Silver
Simon C
SC
Watkins
Toshiro
T
Kageshita
Soldano
S
Ferrone
D000818:Animals; D000918:Antibody Specificity / Q000276:immunology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D000939:Epitopes / Q000276:immunology / Q000378:metabolism; D005260:Female; D006801:Humans; D015151:Immunoblotting; D007167:Immunotherapy / Q000379:methods*; D008175:Lung Neoplasms / Q000276:immunology / Q000517:prevention & control / Q000556:secondary; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008545:Melanoma / Q000276:immunology / Q000473:pathology / Q000628:therapy; D051379:Mice; D016513:Mice, SCID; D018613:Microscopy, Confocal; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009369:Neoplasms / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D019151:Peptide Library; D011485:Protein Binding / Q000276:immunology; D011509:Proteoglycans / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D057127:Single-Chain Antibodies / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use*; D016019:Survival Analysis; D023041:Xenograft Model Antitumor Assays; D000099158:Proteoglycan 4
D000939:Epitopes; D020928:Mitogen-Activated Protein Kinases; D019151:Peptide Library; D011509:Proteoglycans; D057127:Single-Chain Antibodies; C419197:PRG4 protein, human; D000099158:Proteoglycan 4