DNA binding and antiproliferative activity toward human carcinoma cells of copper(ii) and zinc(ii) complexes of a 2,5-diphenyl[1,3,4]oxadiazole derivative
2012; Royal Society of Chemistry; Volume: 41; Issue: 15 Linguagem: Inglês
10.1039/c2dt11759b
ISSN1477-9234
AutoresAlessio Terenzi, Mirco Fanelli, Gianluca Ambrosi, Stefano Amatori, Vieri Fusi, Luca Giorgi, Vincenzo Turco Liveri, Giampaolo Barone,
Tópico(s)Synthesis and Characterization of Heterocyclic Compounds
ResumoThe interaction of calf thymus DNA with [CuL(ClO4)]ClO4·H2O (1) and [ZnLBr]Br·H2O (2) (L = 9,12,15,18,27,28-hexaaza-29-oxatetracyclo[24.2.1.02,7.020,25]enneicosa-2,4,6,20,22,24,26,281-octaene) dicationic complexes in aqueous solution at neutral pH, was investigated by variable-temperature UV-vis absorption, circular dichroism and fluorescence spectroscopy. The values of the DNA-binding constants of these complexes, determined by competitive binding spectrofluorimetric titrations of ethidium bromide (EB)–DNA solutions, are (6.7 ± 0.5) × 106 M−1 for CuL2+ and (4.7 ± 0.5) × 105 M−1 for ZnL2+. These data together with a through analysis of the spectroscopic behaviour consistently suggest that both compounds are effective DNA binders. Interestingly, the DNA-binding strength of these complexes has been found to be correlated to their in vitro cytotoxic activity toward human breast carcinoma cells, although the complex with lower DNA-binding affinity is more active. In fact, biological studies showed that when the compounds are delivered through the cell membrane by a lipidic carrier, the cell survival is sensibly reduced, up to 58% with 1 and to 31% with 2.
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