Natural killer cells are crucial for the efficacy of Icon (factor VII/human IgG1 Fc) immunotherapy in human tongue cancer.

Abstract

BACKGROUND:

Icon is a novel, dual neovascular- and cancer cell-targeting immunotherapeutic agent and has shown efficacy in the treatment of cancer, wet form macular degeneration and endometriosis. However, its underlying mechanism remains to be investigated. The objective of this study is to elucidate the mechanism of Icon immunotherapy in cancer using a squamous carcinoma human tongue cancer line TCA8113 in vitro and in vivo in severe combined immunodeficiency (SCID) mice.

RESULTS:

We showed that Icon, as a chimeric factor VII and human IgG1 Fc immunoconjugate, could separately induce murine natural killer (NK) cells and activate complement to kill TCA8113 cancer cells in vitro via antibody dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). However, Icon-NK ADCC had a significantly stronger effect than that of Icon-CDC. Moreover, Icon could completely eradicate established human tongue tumour xenografts in vivo in the CB-17 strain of SCID mice that have functional NK cells at a normal level, whereas it was less effective in SCID/Beige mice that do not have functional NK cells.

CONCLUSIONS:

We conclude that NK cells are crucial for the efficacy of Icon immunotherapy in the treatment of cancer. The results also suggest that impaired NK level/activity could contribute to the resistance to therapeutic antibodies that are currently under investigation in preclinical and clinical studies.

• Authors: Zhiwei Hu, Jing Li
• Journal: BMC immunology (BMC Immunol) Vol. 11 Pg. 49 (Oct 12 2010) ISSN: 1471-2172 [Electronic] England
• PMID: 20939894 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Immunoglobulin Fc Fragments
• Recombinant Fusion Proteins
• Factor VII

Topics

• Animals
• Antibody-Dependent Cell Cytotoxicity (drug effects)
• Carcinoma, Squamous Cell (drug therapy, immunology)
• Cell Line, Tumor
• Complement Activation (drug effects)
• Cytotoxicity, Immunologic (drug effects)
• Factor VII (genetics, metabolism)
• Humans
• Immunoglobulin Fc Fragments (genetics, metabolism)
• Immunotherapy
• Killer Cells, Natural (drug effects, immunology, metabolism, pathology)
• Lymphocyte Activation (drug effects)
• Mice
• Mice, SCID
• Neoplasm Transplantation
• Recombinant Fusion Proteins (administration & dosage, genetics, metabolism)
• Tongue Neoplasms (drug therapy, immunology)