Characterization of the cell growth inhibitory effects of a novel DNA-intercalating bipyridyl-thiourea-Pt(II) complex in cisplatin-sensitive and -resistant human ovarian cancer cells.
The cellular effects of a novel DNA-intercalating agent, the bipyridyl complex of platinum(II) with diphenyl thiourea, [Pt(bipy)(Ph(2)-tu)(2)]Cl(2), has been analyzed in the cisplatin (cDDP)-sensitive human ovarian carcinoma cell line, 2008, and its -resistant variant, C13* cells, in which the highest accumulation and cytotoxicity was found among six related bipyridyl thiourea complexes. We also show here that this complex causes reactive oxygen species to form and inhibits topoisomerase II activity to a greater extent in the sensitive than in the resistant line. The impairment of this enzyme led to DNA damage, as shown by the comet assay. As a consequence, cell cycle distribution has also been greatly perturbed in both lines. Morphological analysis revealed deep cellular derangement with the presence of cellular masses, together with increased membrane permeability and depolarization of the mitochondrial membrane. Some of these effects, sometimes differentially evident between the two cell lines, might also be related to the decrease of total cell magnesium content caused by this thiourea complex both in sensitive and resistant cells, though the basal content of this ion was higher in the cDDP-resistant line. Altogether these results suggest that this compound exerts its cytotoxicity by mechanisms partly mediated by the resistance phenotype. In particular, cDDP-sensitive cells were affected mostly by impairing topoisomerase II activity and by increasing membrane permeability and the formation of reactive oxygen species; conversely, mitochondrial impairment appeared to play the most important role in the action of complex F in resistant cells.
Marverti
Gaetano
G
Dipartimento di Scienze Biomediche, Sezione di Chimica Biologica, Università di Modena e Reggio Emilia, Via Campi 287, 41100, Modena, Italy. gaetano.marverti@unimore.it
Ligabue
Alessio
A
Montanari
Monica
M
Guerrieri
Davide
D
Cusumano
Matteo
M
Di Pietro
Maria Letizia
ML
Troiano
Leonarda
L
Di Vono
Elena
E
Iotti
Stefano
S
Farruggia
Giovanna
G
Wolf
Federica
F
Monti
Maria Giuseppina
MG
Frassineti
Chiara
C
D015082:2,2'-Dipyridyl / Q000737:chemistry / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D002459:Cell Fusion; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D004273:DNA, Neoplasm / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D004354:Drug Screening Assays, Antitumor; D005260:Female; D006801:Humans; D007364:Intercalating Agents / Q000737:chemistry / Q000494:pharmacology*; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009944:Organoplatinum Compounds / Q000737:chemistry / Q000494:pharmacology*; D010051:Ovarian Neoplasms / Q000201:enzymology / Q000473:pathology*; D017382:Reactive Oxygen Species / Q000378:metabolism
D004273:DNA, Neoplasm; D007364:Intercalating Agents; D009944:Organoplatinum Compounds; D017382:Reactive Oxygen Species; D015082:2,2'-Dipyridyl; D004250:DNA Topoisomerases, Type II; D008274:Magnesium; D002945:Cisplatin