Inhibitory effects of quinolones on pro- and eucaryotic DNA topoisomerases I and II

Abstract

As a means of gaining information on the selectivity of quinolone antibacterial agents, we examined their effect on four topoisomerases, topoisomerases I and H purified from Eschenichia coli and calf thymus. The inhibition of supercoiling and relaxation activities was monitored by using the classical gel electrophoresis assay. Eight quinolones were assayed by using the four enzymes. Gyrase was much more sensitive to quinolones than the other topoisomerases which can therefore be inhibited by moderate concentrations of certain quinolones. No good correlation was observed between the activity on gyrase and on the other enzymes, since the ratio varied from 15 to more than 8,500. On the contrary, there was a good correlation between early inhibition of DNA synthesis, inhibition of gyrase, and MICs.The new fluoroquinolones are strongly bactericidal agents, effective against a broad spectrum of gram-positive and gram-negative bacteria (10,11,17). Their activity is due to the inhibition of bacterial DNA synthesis (38), resulting from inhibition of DNA gyrase (16,32). DNA gyrase belongs to a class of enzymes known as topoisomerases (13,15,29,(42)(43)(44), enzymes that play a crucial role in catalyzing the topological interconversions necessary for DNA replication, transcription, and recombination in procaryotic and eucaryotic cells. These enzymes are the targets of numerous antibacterial and antitumor agents (4,15). While the details of the drug-DNA-topoisomerase interaction are not yet fully elucidated (36), it seems clear that, in the presence of the drug, a complex is formed between enzyme and DNA which, upon exposure to a denaturing agent, results in cleavage of one or both DNA strands (4,26,30,32, 33,37). This irreversible formation of DNA strand breakage induces a sequence of events that leads ultimately to cell death. Recently published data (18,19,24,27,34) MATERIALS AND METHODSChemicals. Nalidixic acid (Winthrop), pefloxacin (mesylate; Roger Bellon), ofloxacin (Hoechst), and ciprofloxacin (chlorhydrate; Bayer) were obtained from their manufacturers in France. BMY 33315, BMY 40062, and BMY 40068 were synthesized by Bristol-Myers France (5, 6, 7) and were 7-piperazynyl-6-fluoro-1-(1,1-dimethylethyl)-1,4-dihydro-4-oxo-1,8-naphtyridine-3-carboxylic acid and its 7-[(1R,4R)-2,5-diaza bicyclo[2.2.1]heptanyl] and 7-(3-amino-1-pyrrolidinyl) derivatives, respectively. CP 67015 was kindly given by Pfizer and was 7-pyridinyl-6,8-difluoro-1-ethyl-1,4-dihydro-4-oxo-pyridine-3-carboxylic acid (24) was added, followed, after 2 min at 37°C, by 1.5 ml of ice cold 10% trichloroacetic acid. The tubes were kept in ice for 30 min and filtered on Whatman GF/C glass fiber filters which were washed twice with 2.5 ml of ice-cold 2.5% trichloroacetic acid and then with ethanol, dried, and counted.

Comparison of inhibition of Escherichia coli topoisomerase IV by quinolones with DNA gyrase inhibition

“…The quinolones were less active against topoisomerase IV decatenation than against DNA gyrase supercoiling. Nevertheless, quinolone activity was still considerably greater against topoisomerase IV decatenation than against topoisomerase I or topoisomerase III relaxation (2,25). The IC50 for NA against topoisomerase IV decatenation was eight times higher than the IC50 for DNA gyrase supercoiling.…”

Purification and inhibition by quinolones of DNA gyrases from Mycobacterium avium, Mycobacterium smegmatis and Mycobacterium fortuitum bv. peregrinum

“…The DNA gyrase supercoiling activity was assessed by measuring the conversion of relaxed plasmid pBR322 DNA to the supercoiled form, as described previously (Bazile et al, 1992 ;Revel-Viravau et al, 1996). The relaxed pBR322 DNA was prepared from the supercoiled form (Boehringer Mannheim) by treatment with prokaryotic topoisomerase I (Eurogentec), as described previously (Moreau et al, 1990).…”

Coral-mucus-associated Vibrio integrons in the Great Barrier Reef: genomic hotspots for environmental adaptation

“…Furthermore, DNA topoisomerase I, present in all bacteria (Forterre et al, 2007) and responsible for removal of excess transcriptionally induced negative DNA supercoiling (Viard and de la Tour, 2007) is sensitive to a few known antibiotics. Even though DNA gyrase is considered the primary target of quinolones from E. coli, some of these have been shown to inhibit the relaxation activity of E. coli topoisomerase I (Tabary et al, 1987;Moreau et al, 1990;Tse-Dinh, 2009). …”