DNA Binding and Topoisomerase I Poisoning Activities of Novel Disaccharide Indolocarbazoles

Abstract

The antibiotics AT2433-A1 and AT2433-B1 are two indolocarbazole diglycosides related to the antitumor drug rebeccamycin known to stabilize topoisomerase I-DNA complexes. This structural analogy prompted us to explore the binding of four indolocarbazole diglycosides with DNA and their capacity to interfere with the DNA cleavage-reunion reaction catalyzed by topoisomerase I. The molecular basis of the drug interaction with double-stranded DNA and with purified chromatin, with particular emphasis on the role of the carbohydrate moiety, was investigated by means of complementary spectroscopic techniques, including surface plasmon resonance and electric linear dichroism. We compared the DNA binding properties, sequence recognition, and effects on topoisomerase I-mediated DNA relaxation and cleavage of AT2433-A1 bearing a 2,4-dideoxy-4-methylamino-L-xylose residue, its dechlorinated analog AT2433-B1, the diastereoisomer iso-AT2433-B1 with an inverted aminosugar residue, and compounds 5H-indolo [2,3-a]pyrrolo [3,4-c]carbazole-5,7(6H)-dione, 12-␤-D-glucopyranosyl-12,13-dihydro-6-methyl (JDC-108) and 5H-indolo[2,3-a]pyrrolo[3, 4-c]carbazole-5,7(6H)-dione, 12-(6-O-␣-D-galacto-pyranosyl-␤-Dglucopyranosyl)-12,13-dihydro-6-methyl (JDC-277) with an uncharged mono-and disaccharide, respectively. The two antibiotics AT2433-A1 and AT2433-B1 proved to be highly cytotoxic to leukemia cells and this may be a consequence of their tight intercalative binding to DNA, preferentially into GC-rich sequences as inferred from DNase I footprinting studies and surface plasmon resonance measurements. Like the diastereoisomer iso-AT2433-B1, they have no inhibitory effect on topoisomerase I, in contrast to the uncharged diglycoside JDC-277, which stimulates DNA cleavage by the enzyme mainly at TG sites, as observed with camptothecin. Cytotoxicity measurements with CEM and CEM/C2 human leukemia cell lines sensitive and resistant to camptothecin, respectively, also suggested that topoisomerase I contributes, at least partially, to the mechanism of action of the neutral diglycoside JDC-277 but not to that of the cationic AT2433 compounds. Together, the results indicate that sequence-selective DNA interaction and topoisomerase I inhibition is controlled to a large extent by the stereochemistry of the diglycoside moiety.

A Novel Small Molecular Weight Compound with a Carbazole Structure That Demonstrates Potent Human Immunodeficiency Virus Type-1 Integrase Inhibitory Activity

“…As compounds with three or four fused aromatic ring structures have been reported to demonstrate intercalative activity (Fukui & Tanaka, 1996;Dziegielewski et al, 2002), we initially suspected that our carbazole derivatives also have intercalative activities, penetrating and disturbing target dsDNA, resulting in pseudo strandtransfer inhibition. Indeed, several carbazole derivatives have been recognized to demonstrate intercalative activity (Facompre et al, 2002;Long et al, 2002). We confirmed that actinomycin D, which is a well-known intercalator (Ross et al, 1979;Wilson & Jones, 1982), demonstrated strand-transfer inhibition in our assay (data not shown).…”

“…Other carbazole derivatives have demonstrated various other activities, such as topoisomerase inhibition (Marotto et al, 2002;Facompre et al, 2002;Carrasco et al, 2001), hypotensive activity (Furusaki et al, 1982), platelet aggregation inhibition (Oka et al, 1986), and anti-fungal activity (Sunthitikawinsakul et al, 2003). In this report we present another possible activity of carbazole derivatives, that of HIV-1 integrase inhibitor.…”

Naphtho[2,3-f]indole-5,10-dione aminoalkyl derivatives: A new class of topoisomerase I inhibitors

“…2, a), they were separated by electrophoresis with EB in gel and buffer. The open circular form migrated slower under these conditions (accumulation of this form indicates specificity of inhibition of DNA relaxation) [3]. Comparison of rows without inhibitors and with 10 and 100 μM camptothecine showed accumulation of the open circular form indicating specificity of inhibition (Fig.…”

Synthesis, Biological Evaluation, and Molecular Modeling Studies of Rebeccamycin Analogues Modified in the Carbohydrate Moiety

“…Interestingly, these compounds have no inhibitory effect on top1 in contrast to the uncharged diglycoside JDC-277, which stimulates DNA cleavage at TG sites as observed with camptothecin. [23][24][25] All these results indicate that the diglycosidic portion represents the primary structural determinant for DNA binding and sequence selectivity of these compounds.…”