A novel anti-EGFR monoclonal antibody inhibiting tumor cell growth by recognizing different epitopes from cetuximab.
The epidermal growth factor receptor (EGFR) overexpressed in many epithelial tumors is an attractive target for tumor therapy since numerous blocking agents of EGFR signaling have proven their anti-tumor activity. Here we report a novel monoclonal antibody (mAb), A13, which was generated from mice immunized with human cervical carcinoma A431 cells. In addition to binding to soluble EGFR with affinity of K(D) approximately 5.8nM, mAb A13 specifically bound to a variety of tumor cells and human placenta tissues expressing EGFR. A13 efficiently inhibited both EGF-dependant EGFR tyrosine phosphorylation in cervical and breast tumor cells and also in vitro colony formation of EGFR-overexpressing lung tumors. Competition and sandwich ELISAs, competitive surface plasmon resonance, and domain-level epitope mapping analyses demonstrated that mAb A13 competitively bound to the domain III (amino acids 302-503) of EGFR with EGF, but recognized distinct epitopes from those of cetuximab (Erbitux). Our results demonstrated that anti-EGFR mAb A13 interfered with EGFR proliferation signaling by blocking EGF binding to EGFR with different epitopes from those of cetuximab, suggesting that combination therapies of mAb A13 with cetuximab may prove beneficial for anti-tumor therapy.
Hong
Kwang-Won
KW
Central Research Center, Green Cross Corp., Bojung-dong, Giheung-gu, Yongin City, Gyunggi-Do, Republic of Korea.
Kim
Chang-Goo
CG
Lee
Seung-Hyun
SH
Chang
Ki-Hwan
KH
Shin
Yong Won
YW
Ryoo
Kyung-Hwan
KH
Kim
Se-Ho
SH
Kim
Yong-Sung
YS
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized; D001483:Base Sequence; D001666:Binding Sites, Antibody; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D000068818:Cetuximab; D004815:Epidermal Growth Factor / Q000378:metabolism; D018604:Epitope Mapping; D000939:Epitopes / Q000276:immunology*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000276:immunology / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D010766:Phosphorylation; D002583:Uterine Cervical Neoplasms / Q000276:immunology
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000939:Epitopes; D004815:Epidermal Growth Factor; C512478:EGFR protein, human; D066246:ErbB Receptors; D000068818:Cetuximab