Oxoazabenzo[de]anthracenes conjugated to amino acids: synthesis and evaluation as DNA-binding antitumor agents.
We report the synthesis of an original series of oxoazabenzo[de]anthracenes conjugated to an amino acid: Ala, Phe, Pro, Lys, or Gly (4a-e, respectively). The compounds, derived from 1,8-dihydroxyanthracene-9,10-dione, were studied for DNA binding and cytotoxicity. Melting temperature, fluorescence quenching, and surface plasmon resonance methods all indicated that the lysine derivative 4d binds to DNA much more strongly that the Pro, Ala, and Gly conjugates whereas the Phe analogue showed the lowest DNA binding capacity. These compounds form intercalation complexes with DNA, as judged from electric linear dichroism and topoisomerase I-based DNA unwinding experiments. Preferential binding of 4d to defined sequences such as 5'-CTAAAGG and 5'-ATGC was evidenced by DNase I footprinting. This Lys conjugate was found to be over 20 times more cytotoxic to CEM human leukemia cells than the other conjugates, with an IC50 in the submicromolar range. A high antiproliferative activity, likely attributable to the enhanced DNA binding capacity, is maintained despite the incapacity of the compound to stabilize topoisomerase-DNA covalent complexes. The cell cycle effects of 4d consisted in an S phase accumulation of cells coupled with a pro-apoptotic action (appearance of hypodiploid sub-G1 cells) which were confirmed by measuring the inhibition of BrdU incorporation into DNA and labeling of phosphatidylserine residues with annexin V-FITC by means of flow cytometry. Altogether, the work provides interesting structure-activity relationships in the oxoazabenzo[de]anthracene-amino acid conjugate series and identifies the lysine derivative 4d as a promising candidate for further in vivo evaluation and drug design.
Dias
Nathalie
N
INSERM U-524 et Laboratoire de Pharmacologie Antitumorale du Centre Oscar Lambret, IRCL, 59045 Lille, France.
Goossens
Jean-François
JF
Baldeyrou
Brigitte
B
Lansiaux
Amélie
A
Colson
Pierre
P
Di Salvo
Alberto
A
Bernal
Jeanne
J
Turnbull
Agnes
A
Mincher
David J
DJ
Bailly
Christian
C
D000596:Amino Acids / Q000737:chemistry*; D000873:Anthracenes / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001973:Bromodeoxyuridine; D002453:Cell Cycle; D045744:Cell Line, Tumor; D004247:DNA / Q000187:drug effects*; D018983:DNA Footprinting; D004354:Drug Screening Assays, Antitumor; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry / Q000379:methods*; D013050:Spectrometry, Fluorescence; D020349:Surface Plasmon Resonance; D059004:Topoisomerase I Inhibitors
D000596:Amino Acids; D000873:Anthracenes; D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D059004:Topoisomerase I Inhibitors; D004247:DNA; D001973:Bromodeoxyuridine