Enhanced Antitumor Activity against Melanoma Cancer Cells by Nitric Oxide Release and Photosensitized Generation of Singlet Oxygen from Ruthenium Complexes

MARCHESI, M. S. P.; LUNARDI, C. N.; DA SILVA, R. S.; RAMOS, L. C. B.; BARUFFI M. D.; BENDHACK, L. M.; CALLEJON, D.; SLEP, L. D.

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2016 vol. 5 p. 3592 - 3597

1434-1948

We have investigated the synergistic effect of nitric oxide and singlet oxygen originating from stimulated ruthenium complexes and their photodynamic action against a melanoma cancer cell line. In aqueous solution, the photosensitizer[Ru(NH3)5(pz)]2+ (I; pz = pyrazine) and the nitrosylruthenium complex trans-[RuCl([15]aneN4)NO]2+ (II; [15]aneN4 = 1,4,8,12-tetrazacyclopentadecane) can produce singlet oxygen and nitric oxide, respectively. The phototoxicity of complex I does not correlate with the singlet oxygen quantum yields unless it is mediated by nitric oxide release from complex II. This effect is around 70 and 50 % higher than the effect prompted by compounds I and II, respectively, in isolation in the presence of light. It was found that the number of hypodiploid cells in the melanoma cancer cells increased which indicates that a mixture of compounds I and II induces apoptosis of tumorigenic cell lines. Both singlet oxygen and nitric oxide produced by the ruthenium complexes enhance the photodynamic efficacy in melanoma cancer cells.