title: DNA interactions of 2-pyrrolinodoxorubicin, a distinctively more potent daunosamine-modified analogue of doxorubicin.
abstract: It was shown earlier that 2-pyrrolinodoxorubicin was 500-1000 times more active towards human and mouse cancer cells in vitro than parental doxorubicin. However, the biochemical factors responsible for such a large difference in potency between doxorubicin and 2-pyrrolinodoxorubicin are not clear at the molecular level. To provide this information, we have investigated in cell-free media by biochemical and biophysical methods interactions of both anthracyclines with DNA, effects of these interactions on activity of human topoisomerase II, human Bloom's syndrome helicase and prokaryotic T7 RNA polymerase, and the capability of these drugs to form DNA interstrand cross-links in formaldehyde-free medium. Experiments aimed at understanding the properties of double-helical DNA in the presence of doxorubicin and 2-pyrrolinodoxorubicin revealed only small differences in DNA modifications by these anthracyclines and resulting conformational alterations in DNA. Similarly, the ability of 2-pyrrolinodoxorubicin modifications of DNA to inhibit catalytic activity of topoisomerase II does not differ significantly from that of doxorubicin. On the other hand, we demonstrate that an important factor responsible for the markedly higher antiproliferative potency of DNA modifications by 2-pyrrolinodoxorubicin is capability of these modifications to inhibit downstream cellular processes which process DNA damaged by this drug and involve separation of complementary strands of DNA, such as DNA unwinding by helicases or RNA polymerases. In addition, the results are also consistent with the hypothesis that in particular the capability of 2-pyrrolinodoxorubicin to readily form DNA interstrand cross-links is responsible for inhibition of these processes in the cells treated with this analogue of doxorubicin.
authors.affiliation: Institute of Biophysics, Academy of Science of the Czech Republic, v.v.i., Kralovopolska 135, CZ-61265 Brno, Czech Republic.
authors.forename: Jana
authors.initials: J
authors.lastname: Stepankova
authors.forename: Martin
authors.initials: M
authors.lastname: Studenovsky
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Malina
authors.forename: Jana
authors.initials: J
authors.lastname: Kasparkova
authors.forename: Barbora
authors.initials: B
authors.lastname: Liskova
authors.forename: Olga
authors.initials: O
authors.lastname: Novakova
authors.forename: Karel
authors.initials: K
authors.lastname: Ulbrich
authors.forename: Viktor
authors.initials: V
authors.lastname: Brabec
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002474:Cell-Free System; D004247:DNA / Q000378:metabolism*; D018736:DNA Adducts; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D004317:Doxorubicin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006595:Hexosamines / Q000737:chemistry*; D006801:Humans; D051379:Mice; D015394:Molecular Structure; D011758:Pyrroles / Q000378:metabolism / Q000494:pharmacology; D059005:Topoisomerase II Inhibitors / Q000378:metabolism / Q000494:pharmacology; D014158:Transcription, Genetic
chemical_list: D000970:Antineoplastic Agents; D018736:DNA Adducts; D006595:Hexosamines; D011758:Pyrroles; D059005:Topoisomerase II Inhibitors; C098751:AN 204; C007217:daunosamine; D004317:Doxorubicin; D004247:DNA; D004250:DNA Topoisomerases, Type II