Antibody blockade of the Cripto CFC domain suppresses tumor cell growth in vivo.
Cripto, a cell surface-associated protein belonging to the EGF-CFC family of growth factor-like molecules, is overexpressed in many human solid tumors, including 70-80% of breast and colon tumors, yet how it promotes cell transformation is unclear. During embryogenesis, Cripto complexes with Alk4 via its unique cysteine-rich CFC domain to facilitate signaling by the TGF-beta ligand Nodal. We report, for the first time to our knowledge, that Cripto can directly bind to another TGF-beta ligand, Activin B, and that Cripto overexpression blocks Activin B growth inhibition of breast cancer cells. This result suggests a novel mechanism for antagonizing Activin signaling that could promote tumorigenesis by deregulating growth homeostasis. We show that an anti-CFC domain antibody, A8.G3.5, both disrupts Cripto-Nodal signaling and reverses Cripto blockade of Activin B-induced growth suppression by blocking Cripto's association with either Alk4 or Activin B. In two xenograft models, testicular and colon cancer, A8.G3.5 inhibited tumor cell growth by up to 70%. Both Nodal and Activin B expression was found in the xenograft tumor, suggesting that either ligand could be promoting tumorigenesis. These data validate that functional blockade of Cripto inhibits tumor growth and highlight antibodies that block Cripto signaling mediated through its CFC domain as an important class of antibodies for further therapeutic development.
Adkins
Heather B
HB
Biogen Inc., 14 Cambridge Center, Cambridge, Massachusetts 02142, USA.
Bianco
Caterina
C
Schiffer
Susan G
SG
Rayhorn
Paul
P
Zafari
Mohammad
M
Cheung
Anne E
AE
Orozco
Olivia
O
Olson
Dian
D
De Luca
Antonella
A
Chen
Ling Ling
LL
Miatkowski
Konrad
K
Benjamin
Chris
C
Normanno
Nicola
N
Williams
Kevin P
KP
Jarpe
Matthew
M
LePage
Doreen
D
Salomon
David
D
Sanicola
Michele
M
D030201:Activin Receptors, Type I / Q000378:metabolism; D028341:Activins / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D001943:Breast Neoplasms / Q000473:pathology; D016466:CHO Cells; D002455:Cell Division; D002469:Cell Separation; D002471:Cell Transformation, Neoplastic; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D004815:Epidermal Growth Factor; D000939:Epitopes; D005434:Flow Cytometry; D058851:GPI-Linked Proteins; D006801:Humans; D015151:Immunoblotting; D007074:Immunoglobulin G / Q000378:metabolism; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D008297:Male; D008562:Membrane Glycoproteins; D051379:Mice; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000737:chemistry* / Q000276:immunology*; D009368:Neoplasm Transplantation; D055457:Nodal Protein; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011506:Proteins; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000378:metabolism; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000939:Epitopes; D058851:GPI-Linked Proteins; D007074:Immunoglobulin G; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D008562:Membrane Glycoproteins; C526007:NODAL protein, human; D009363:Neoplasm Proteins; D055457:Nodal Protein; C526008:Nodal protein, mouse; D011506:Proteins; D012333:RNA, Messenger; C070636:TDGF1 protein, human; C489450:Tdgf1 protein, mouse; D016212:Transforming Growth Factor beta; C044147:activin B; D028341:Activins; D004815:Epidermal Growth Factor; C425423:ACVR1 protein, human; C498932:ACVR1B protein, human; D030201:Activin Receptors, Type I; C498933:Acvr1b protein, mouse