PEG chains increase aspermatogenic and antitumor activity of RNase A and BS-RNase enzymes.
RNase A (bovine pancreatic ribonuclease) and BS-RNase (bovine seminal ribonuclease) are monomeric and dimeric enzymes, respectively, with aspermatogenic and antitumor activities. While the aspermatogenic and, in some experimental situations, the antitumor effects of the RNase A are only minor, the activity of BS-RNase in these phenomena is very significant. These differences can be annulled by means of conjugation of the enzymes with PEG (polyethylene glycol) chains. Aspermatogenic activity was studied histologically following subcutaneous injections of RNase A and BS-RNase conjugates in ICR mice, and the antitumor activity in athymic nude mice with growing human melanoma with i.p. injection of these conjugated ribonucleases. The experiments proved that RNase A, when conjugated to PEG, produced identical aspermatogenic and antitumour effects as BS-RNase conjugated to this polymer. Immunogenicity of RNase A and BS-RNase did not change substantially after the conjugation with PEG polymers. Binding of produced antibodies to both ribonucleases attached to PEG, however, was substantially reduced.
Matousek
Josef
J
Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Libechov 27721, Czech Republic. matousek@iapg.cas.cz
Poucková
Pavla
P
Soucek
Josef
J
Skvor
Jirí
J
D000818:Animals; D000917:Antibody Formation / Q000187:drug effects; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D000988:Antispermatogenic Agents / Q000737:chemistry / Q000494:pharmacology*; D002417:Cattle; D004354:Drug Screening Assays, Antitumor; D004722:Endoribonucleases / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D007274:Injections, Intraperitoneal; D007279:Injections, Subcutaneous; D008297:Male; D008546:Melanoma, Experimental / Q000188:drug therapy; D051379:Mice; D008813:Mice, Inbred ICR; D008819:Mice, Nude; D011092:Polyethylene Glycols / Q000737:chemistry*; D012259:Ribonuclease, Pancreatic / Q000737:chemistry / Q000494:pharmacology*; D012661:Semen / Q000737:chemistry; D013091:Spermatogenesis / Q000187:drug effects; D013737:Testis / Q000187:drug effects
D000970:Antineoplastic Agents; D000988:Antispermatogenic Agents; D011092:Polyethylene Glycols; D004722:Endoribonucleases; C032523:ribonuclease SPL; D012259:Ribonuclease, Pancreatic