A human cytokine/single-chain antibody fusion protein for simultaneous delivery of GM-CSF and IL-2 to Ep-CAM overexpressing tumor cells.
Pro-inflammatory cytokines regulate the growth, differentiation, and activation of immune cells and can play a role in antitumor responses. GM-CSF and IL-2 induce tumor rejection in animal models when expressed by tumor cells, and IL-2 is used for the treatment of melanoma and renal cell cancer. However, high doses of GM-CSF and IL-2 are associated with severe side effects in cancer patients. We generated a dual cytokine fusion protein for simultaneous targeted delivery of human GM-CSF and IL-2 to human tumors. The fusion protein is based on a heterodimeric core structure formed by human CH1 and C kappa domains (heterominibody) with C-terminally fused human cytokines and N-terminally fused human single-chain Ab fragments (scFv) specific for the tumor-associated surface antigen epithelial cell adhesion molecule (Ep-CAM). The dual cytokine heterominibody (DCH) was well expressed and secreted by CHO cells, preserved the specific proliferative activities of the two cytokines, and showed Ep-CAM-specific binding to tumor cells. DCH induced potent tumor cell lysis in vitro by two distinct mechanisms. One was activating PBMCs to lyse tumor cells, which was superior to cytotoxicity induced by equimolar ratios of free recombinant human IL-2 and GM-CSF. The other mechanism was redirected lysis, as seen with isolated human T cells, which was solely dependent on the IL-2 fusion part. The therapeutic principle of dual cytokine targeting may warrant in vivo testing of murine-specific analogues in appropriate mouse models and further preclinical development of the less immunogenic, human cytokine- and human Ep-CAM-specific DCH molecule described here.
Micromet AG, Staffelseestr. 2, 81477 Munich, Germany.
Juergen M
JM
Schanzer
Patrick A
PA
Baeuerle
Torsten
T
Dreier
Peter
P
Kufer
D000818:Animals; D000906:Antibodies / Q000008:administration & dosage; D000951:Antigens, Neoplasm / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000276:immunology; D016466:CHO Cells; D015815:Cell Adhesion Molecules / Q000008:administration & dosage / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D045744:Cell Line, Tumor; D006224:Cricetinae; D003602:Cytotoxicity, Immunologic; D004195:Disease Models, Animal; D004338:Drug Combinations; D016503:Drug Delivery Systems; D004591:Electrophoresis, Polyacrylamide Gel; D000071858:Epithelial Cell Adhesion Molecule; D004847:Epithelial Cells / Q000737:chemistry / Q000166:cytology; D014644:Genetic Variation; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000008:administration & dosage* / Q000235:genetics; D006801:Humans; D007376:Interleukin-2 / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000235:genetics; D011994:Recombinant Proteins; D013601:T-Lymphocytes / Q000276:immunology
D000906:Antibodies; D000951:Antigens, Neoplasm; D000970:Antineoplastic Agents; D015815:Cell Adhesion Molecules; D004338:Drug Combinations; C499379:EPCAM protein, human; D000071858:Epithelial Cell Adhesion Molecule; D007376:Interleukin-2; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; C082598:aldesleukin