Insights into HER2 signaling from step-by-step optimization of anti-HER2 antibodies.
HER2, a ligand-free tyrosine kinase receptor of the HER family, is frequently overexpressed in breast cancer. The anti-HER2 antibody trastuzumab has shown significant clinical benefits in metastatic breast cancer; however, resistance to trastuzumab is common. The development of monoclonal antibodies that have complementary mechanisms of action results in a more comprehensive blockade of ErbB2 signaling, especially HER2/HER3 signaling. Use of such antibodies may have clinical benefits if these antibodies can become widely accepted. Here, we describe a novel anti-HER2 antibody, hHERmAb-F0178C1, which was isolated from a screen of a phage display library. A step-by-step optimization method was employed to maximize the inhibitory effect of this anti-HER2 antibody. Crystallographic analysis was used to determine the three-dimensional structure to 3.5 Å resolution, confirming that the epitope of this antibody is in domain III of HER2. Moreover, this novel anti-HER2 antibody exhibits superior efficacy in blocking HER2/HER3 heterodimerization and signaling, and its use in combination with pertuzumab has a synergistic effect. Characterization of this antibody revealed the important role of a ligand binding site within domain III of HER2. The results of this study clearly indicate the unique potential of hHERmAb-F0178C1, and its complementary inhibition effect on HER2/HER3 signaling warrants its consideration as a promising clinical treatment.
Central Laboratory; Navy General Hospital; Beijing, PR China; Cancer Center; PLA General Hospital; PLA Postgraduate School of Medicine; Beijing, PR China.
Wenyan
W
Fu
Central Laboratory; Navy General Hospital; Beijing, PR China.
Yuxiao
Y
Wang
Department of Ultrasound in Medicine; Navy General Hospital; Beijing, PR China.
Yunshan
Y
Zhang
Central Laboratory; Navy General Hospital; Beijing, PR China.
Lijuan
L
Xiong
Department of Biochemistry; Norman Institute for Cancer Research; Toronto, ON CA.
Hiroaki
H
Takeda
Central Laboratory; Navy General Hospital; Beijing, PR China.
Li
L
Ding
The Department of Laboratory Medicine; State Grid Beijing Electric Power Hospital; Beijing, PR China.
Qunfang
Q
Xu
Central Laboratory; Navy General Hospital; Beijing, PR China.
Lidong
L
He
Beijing Institute of Radiation Medicine; Beijing, PR China.
Wenlong
W
Tan
Department of Molecular Oncology; Norman Institute for Cancer Research; Toronto, ON CA.
Augus N
AN
Bethune
Central Laboratory; Navy General Hospital; Beijing, PR China.
Lijun
L
Zhou
D000818:Animals; D061067:Antibodies, Monoclonal, Humanized / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D000912:Antibodies, Neoplasm / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000276:immunology / Q000494:pharmacology; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000276:immunology / Q000473:pathology; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D015202:Protein Engineering / Q000379:methods; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000276:immunology; D020893:Receptor, ErbB-3 / Q000276:immunology; D015398:Signal Transduction / Q000187:drug effects* / Q000276:immunology; D000068878:Trastuzumab
D061067:Antibodies, Monoclonal, Humanized; D000912:Antibodies, Neoplasm; D000970:Antineoplastic Agents; D018719:Erb-b2 Receptor Tyrosine Kinases; D020893:Receptor, ErbB-3; D000068878:Trastuzumab; C508053:ERBB2 protein, human; C581292:ERBB3 protein, human; C485206:pertuzumab
HER2; breast cancer; crystal structure; transmembrane signal transduction; trastuzumab resistance