HER2 monoclonal antibodies that do not interfere with receptor heterodimerization-mediated signaling induce effective internalization and represent valuable components for rational antibody-drug conjugate design.
The human epidermal growth factor receptor (HER)2 provides an excellent target for selective delivery of cytotoxic drugs to tumor cells by antibody-drug conjugates (ADC) as has been clinically validated by ado-trastuzumab emtansine (Kadcyla(TM)). While selecting a suitable antibody for an ADC approach often takes specificity and efficient antibody-target complex internalization into account, the characteristics of the optimal antibody candidate remain poorly understood. We studied a large panel of human HER2 antibodies to identify the characteristics that make them most suitable for an ADC approach. As a model toxin, amenable to in vitro high-throughput screening, we employed Pseudomonas exotoxin A (ETA') fused to an anti-kappa light chain domain antibody. Cytotoxicity induced by HER2 antibodies, which were thus non-covalently linked to ETA', was assessed for high and low HER2 expressing tumor cell lines and correlated with internalization and downmodulation of HER2 antibody-target complexes. Our results demonstrate that HER2 antibodies that do not inhibit heterodimerization of HER2 with related ErbB receptors internalize more efficiently and show greater ETA'-mediated cytotoxicity than antibodies that do inhibit such heterodimerization. Moreover, stimulation with ErbB ligand significantly enhanced ADC-mediated tumor kill by antibodies that do not inhibit HER2 heterodimerization. This suggests that the formation of HER2/ErbB-heterodimers enhances ADC internalization and subsequent killing of tumor cells. Our study indicates that selecting HER2 ADCs that allow piggybacking of HER2 onto other ErbB receptors provides an attractive strategy for increasing ADC delivery and tumor cell killing capacity to both high and low HER2 expressing tumor cells.
Genmab; Utrecht, the Netherlands.
Bart E C G
BE
de Goeij
Division of Stem Cell Transplantation and Immunotherapy; 2nd Department of Medicine; Christian-Albrechts-University; Kiel, Germany.
Matthias
M
Peipp
Genmab; Utrecht, the Netherlands.
Simone
S
de Haij
Genmab; Utrecht, the Netherlands.
Edward N
EN
van den Brink
Division of Stem Cell Transplantation and Immunotherapy; 2nd Department of Medicine; Christian-Albrechts-University; Kiel, Germany.
Christian
C
Kellner
Genmab; Utrecht, the Netherlands.
Thilo
T
Riedl
Genmab; Utrecht, the Netherlands.
Rob
R
de Jong
Genmab; Utrecht, the Netherlands.
Tom
T
Vink
Genmab; Utrecht, the Netherlands.
Kristin
K
Strumane
Genmab; Utrecht, the Netherlands.
Wim K
WK
Bleeker
Genmab; Utrecht, the Netherlands.
Paul W H I
PW
Parren
D061067:Antibodies, Monoclonal, Humanized / Q000494:pharmacology / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000276:immunology / Q000628:therapy*; D045744:Cell Line, Tumor; D019281:Dimerization; D015195:Drug Design; D004705:Endocytosis; D004815:Epidermal Growth Factor / Q000378:metabolism; D005260:Female; D006801:Humans; D007167:Immunotherapy / Q000379:methods*; D000922:Immunotoxins / Q000627:therapeutic use; D011940:Receptor Aggregation / Q000187:drug effects; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology; D015398:Signal Transduction / Q000187:drug effects; D000068878:Trastuzumab
D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D004815:Epidermal Growth Factor; D000922:Immunotoxins; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C508053:ERBB2 protein, human
HER2; Pseudomonasexotoxin A; antibody-drug conjugate; cancer; monoclonal antibody