title: In vitro biochemical and pharmacological evaluation of a novel cytotoxic dinuclear platinum(II) complex with 3-amino-5-methyl-5-phenylhydantoin.
abstract: An in vitro pharmacological evaluation of a novel dinuclear platinum complex ([KL(2)](2)[Pt(2)I(6)], where L is 3-amino-5-methyl-5-phenylhydantoin; Ad-1) was carried out. The cytotoxicity of [KL(2)](2)[Pt(2)I(6)] against human tumor cell lines was assessed using the MTT [-3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide] assay. The complex exerted concentration-dependent cytotoxic effects that were comparable or even superior to that of cisplatin. Moreover, the novel complex retained significant activity against CaCo-2 and Neuro-2A cells, which showed primary resistance to cisplatin. As evidenced by the rising level of genomic DNA fragmentation following treatment with [KL(2)](2)[Pt(2)I(6)], the cytotoxic effects are at least partly mediated by induction of apoptosis. The DNA binding of [KL(2)](2)[Pt(2)I(6)] and cisplatin were assessed using a 40-base fragment, whereby the present GG-motif is the recognition sequence of the nuclease BamH1. The DNA platination was determined after BamH1 treatment, 5% PAGE, and ethidium bromide staining. Cisplatin completely inhibited the BamH1-mediated fragmentation of the target DNA molecule. [KL(2)](2)[Pt(2)I(6)] also significantly inhibited the fragmentation of the target DNA sequence. The platination induced by [KL(2)](2)[Pt(2)I(6)] was better repaired by the nucleotide excision repair than the cisplatin lesions. As evidenced by electrophoresis mobility shift assay, the Ad-1-modified DNA was efficiently recognized and bound by the high mobility group box (HMGB)-1 protein, a member of the HMG domain proteins, which implies that the latter are most probably important for the cytotoxicity mode of action of this agent.
authors.affiliation: Department of Pharmacology, Pharmacotherapy and Toxicology, Medical University-Sofia, Sofia, Bulgaria.
authors.forename: Georgi Ts
authors.initials: GTs
authors.lastname: Momekov
authors.forename: Iva
authors.initials: I
authors.lastname: Ugrinova
authors.forename: Evdokia A
authors.initials: EA
authors.lastname: Pasheva
authors.forename: Adriana G
authors.initials: AG
authors.lastname: Bakalova
authors.forename: Hristo Pl
authors.initials: HP
authors.lastname: Varbanov
authors.forename: Dilyan V
authors.initials: DV
authors.lastname: Ferdinandov
authors.forename: Darvin Sl
authors.initials: DS
authors.lastname: Ivanov
authors.forename: Spiro M
authors.initials: SM
authors.lastname: Konstantinov
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D018938:Caco-2 Cells; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology; D053938:DNA Fragmentation / Q000187:drug effects; D004260:DNA Repair; D004273:DNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D024202:Electrophoretic Mobility Shift Assay; D018922:HL-60 Cells; D024243:HMGB1 Protein / Q000378:metabolism; D006801:Humans; D006827:Hydantoins / Q000737:chemistry / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D020014:K562 Cells; D015394:Molecular Structure; D009944:Organoplatinum Compounds / Q000737:chemistry / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects
chemical_list: C543701:3-amino-5-methyl-5-phenylhydantoin; D000970:Antineoplastic Agents; D004273:DNA, Neoplasm; D024243:HMGB1 Protein; D006827:Hydantoins; D009944:Organoplatinum Compounds; D002945:Cisplatin