Antibody blockade of the Cripto CFC domain suppresses tumor cell growth in vivo
Heather B. Adkins, … , David Salomon, Michele Sanicola
Heather B. Adkins, … , David Salomon, Michele Sanicola
Published August 15, 2003
Citation Information: J Clin Invest. 2003;112(4):575-587. https://doi.org/10.1172/JCI17788.
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Article Oncology

Antibody blockade of the Cripto CFC domain suppresses tumor cell growth in vivo

Abstract

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-β ligand Nodal. We report, for the first time to our knowledge, that Cripto can directly bind to another TGF-β 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.

Authors

Heather B. Adkins, Caterina Bianco, Susan G. Schiffer, Paul Rayhorn, Mohammad Zafari, Anne E. Cheung, Olivia Orozco, Dian Olson, Antonella De Luca, Ling Ling Chen, Konrad Miatkowski, Chris Benjamin, Nicola Normanno, Kevin P. Williams, Matthew Jarpe, Doreen LePage, David Salomon, Michele Sanicola

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Figure 1

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(a) Diagram of mature hCr protein: N-terminal tip (black), N-terminal re...
(a) Diagram of mature hCr protein: N-terminal tip (black), N-terminal region (blue), EGF-like domain (red), and CFC domain (green). Amino acid 169 is N-terminal to the GPI-linkage site. Asterisks indicate positions of mutants described in Table 1. (b) Western blot of Cripto expressed in CHO cells (recombinant) or endogenously expressed in NCCIT and GEO tumor cell lines using A10.B2.18. (c) Immunofluorescent staining of cell surface Cripto on human breast tumor tissue with A10.B2.18 (left) or control antibody 1E6 (right). (d) Immunohistochemical staining of tumor sections with anti-Cripto mAb’s A10.B2.18 (breast and NCCIT) and B3.F6.17 (colon and GEO) or mouse IgG as a negative control. Color variations result from the use of different substrates, either Vector NovaRED or DAB substrate kits (Vector Laboratories Inc.).