Superior activity of fusion protein scFvRit:sFasL over cotreatment with rituximab and Fas agonists.
The clinical efficacy of the CD20-specific chimeric monoclonal antibody rituximab is significantly hampered by intrinsic or acquired resistance to therapy. Rituximab activates antibody-dependent cellular cytotoxicity/complement-dependent cytotoxicity-dependent lysis but also induces apoptosis by cross-linking of its target antigen CD20. Recent reports indicate that this apoptotic activity of rituximab can be synergized by cotreatment with Fas agonists. Here, we report on a strategy designed to exploit and optimize the synergy between rituximab and Fas signaling by genetically fusing a rituximab-derived antibody fragment to soluble Fas ligand (sFasL). The resultant fusion protein, designated scFvRit:sFasL, potently induced CD20-restricted apoptosis in a panel of malignant B-cell lines (10 of 11) and primary patient-derived malignant B cells (two of two non-Hodgkin lymphoma and five of six B cell chronic lymphocytic leukemia). ScFvRit:sFasL efficiently activated CD20 and Fas apoptotic signaling, resulting in a far superior proapoptotic activity compared with cotreatment with rituximab and Fas agonists. ScFvRit:sFasL lacked activity toward normal human B cells and also lacked systemic toxicity in nude mice with no elevation of aspartate aminotransferase and alanine aminotransferase levels or liver caspase-3 activity. In conclusion, scFvRit:sFasL efficiently activates CD20 and Fas-apoptotic signaling and may be useful for the elimination of malignant B cells.
Bremer
Edwin
E
Groningen University Institute for Drug Exploration, Department of Pathology and Laboratory Medicine, University Medical Center Groningen, Groningen, the Netherlands.
ten Cate
Bram
B
Samplonius
Douwe F
DF
Mueller
Nicole
N
Wajant
Harald
H
Stel
Alja J
AJ
Chamuleau
Martine
M
van de Loosdrecht
Arjan A
AA
Stieglmaier
Julia
J
Fey
Georg H
GH
Helfrich
Wijnand
W
D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage*; D058846:Antibodies, Monoclonal, Murine-Derived; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001402:B-Lymphocytes / Q000187:drug effects; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D053222:Fas Ligand Protein / Q000819:agonists*; D005260:Female; D015316:Genetic Therapy / Q000009:adverse effects / Q000379:methods; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics / Q000628:therapy*; D008228:Lymphoma, Non-Hodgkin / Q000235:genetics / Q000628:therapy*; D008297:Male; D011993:Recombinant Fusion Proteins / Q000009:adverse effects / Q000235:genetics* / Q000627:therapeutic use*; D000069283:Rituximab; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D057127:Single-Chain Antibodies; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D011993:Recombinant Fusion Proteins; D057127:Single-Chain Antibodies; C526446:scFvRit-sFasL protein, human; D000069283:Rituximab