Evaluation of human pancreatic RNase as effector molecule in a therapeutic antibody platform.
Human antibody-ribonuclease (RNase) fusion proteins, referred to as immunoRNases, have been proposed as an alternative to heterologous immunotoxins, without their immunogenicity and unspecific toxicity issues. In this study, we investigated if human pancreatic RNase will be suitable as effector component in a therapeutic antibody development platform. We generated several fusion proteins consisting of tumor-specific human immunoglobulins (IgGs) and human pancreatic RNase. Transient mammalian cell production was efficient and IgG-RNases were purified to homogeneity. Antigen binding was comparable to the parental antibodies and RNase catalytic activity was retained even in the presence of 50-fold molar excess of human cytosolic RNase inhibitor (RI). Serum stability, cell binding and internalization of IgG-RNases were comparable to the parental IgGs. Despite these promising properties, none of the IgG-RNases revealed significant inhibition of tumor cell growth in vitro even when targeting different antigens putatively employing different endocytotic pathways. The introduction of different linkers containing endosomal protease cleavage sites into the IgG-RNase did not enhance cytotoxicity. Similarly, RI evasive human pancreatic RNase variants mediated only small inhibiting effects on tumor cell growth at high concentrations, potentially reflecting inefficient cytosolic translocation. Taken together, human pancreatic RNase and variants did not prove to be generally suitable as effector component for a therapeutic antibody drug development platform.
University of Braunschweig; Institute of Biochemistry, Biotechnology and Bioinformatics; Braunschweig, Germany.
Thomas
T
Schirrmann
University of Braunschweig; Institute of Biochemistry, Biotechnology and Bioinformatics; Braunschweig, Germany.
André
A
Frenzel
Bayer Healthcare AG; Global Biologics; Wuppertal, Germany.
Lars
L
Linden
Bayer Healthcare AG; Global Biologics; Wuppertal, Germany.
Beatrix
B
Stelte-Ludwig
Bayer HealthCare AG; Therapeutic Research Group Oncology & Gynecological Therapies; Berlin, Germany.
Jörg
J
Willuda
Bayer Healthcare AG; Global Biologics; Wuppertal, Germany.
Axel
A
Harrenga
University of Braunschweig; Institute of Biochemistry, Biotechnology and Bioinformatics; Braunschweig, Germany.
Stefan
S
Dübel
Bayer Healthcare AG; Global Biologics; Wuppertal, Germany.
Beate
B
Müller-Tiemann
Bayer Healthcare AG; Global Biologics; Wuppertal, Germany.
Mark
M
Trautwein
D000230:Adenocarcinoma / Q000188:drug therapy* / Q000276:immunology; D017151:Antibodies, Catalytic / Q000235:genetics / Q000378:metabolism*; D000951:Antigens, Neoplasm / Q000276:immunology; D048708:Cell Growth Processes / Q000187:drug effects; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D004705:Endocytosis; D057809:HEK293 Cells; D019073:HT29 Cells; D006801:Humans; D007074:Immunoglobulin G / Q000235:genetics / Q000378:metabolism*; D007167:Immunotherapy / Q000379:methods* / Q000639:trends; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000276:immunology; D058990:Molecular Targeted Therapy; D010179:Pancreas / Q000201:enzymology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism*; D012260:Ribonucleases / Q000235:genetics / Q000378:metabolism*
D017151:Antibodies, Catalytic; D000951:Antigens, Neoplasm; D007074:Immunoglobulin G; D011993:Recombinant Fusion Proteins; D012260:Ribonucleases
IgG; RNase inhibitor; antibodies; cancer therapy; human pancreatic RNase; immunoRNase; immunoglobulin