Antibody-onconase conjugates: cytotoxicity and intracellular routing.
Onconase, a member of the pancreatic ribonuclease A superfamily, is currently in Phase III clinical trials for treatment of unresectable malignant mesothelioma. The anticancer effect of onconase may relate to its intracellular target, a non-coding RNA. Some non-coding RNAs are aberrantly expressed in cancer cells. This discovery is creating new interest in drugs that target RNA. Conjugating onconase to agents that recognize tumor associated molecules further increases its potency and specificity. Analysis of onconase activity when directed to two different internalizing and one non-internalizing receptor reveals that the ideal targeting agents would rapidly enter lysosomal compartments before onconase escaped to the cytosol. Antibody-onconase conjugates are effective in preclinical models, cause little non-specific toxicities in mice and have favorable formulation properties. Understanding the reason for their potency coupled with understanding novel RNA-based mechanisms of tumor cell death will lead to improved variations of targeted onconase.
Rybak
S M
SM
Bionanomics, LLC, 411 Walnut Street, Green Cove Springs, FL 32043, USA. rybak@mindspring.com
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000276:immunology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000276:immunology / Q000494:pharmacology / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D016503:Drug Delivery Systems; D004705:Endocytosis / Q000187:drug effects*; D006801:Humans; D018796:Immunoconjugates / Q000008:administration & dosage / Q000276:immunology / Q000494:pharmacology / Q000627:therapeutic use*; D008826:Microbial Sensitivity Tests; D009369:Neoplasms / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism; D011990:Receptors, Transferrin / Q000276:immunology; D012260:Ribonucleases / Q000008:administration & dosage / Q000276:immunology / Q000494:pharmacology / Q000627:therapeutic use*; D051918:Sialic Acid Binding Ig-like Lectin 2 / Q000276:immunology
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000911:Antibodies, Monoclonal; D018796:Immunoconjugates; D011990:Receptors, Transferrin; D051918:Sialic Acid Binding Ig-like Lectin 2; D012260:Ribonucleases; C058703:ranpirnase