title: Analysis of the DNA damage produced by a platinum-acridine antitumor agent and its effects in NCI-H460 lung cancer cells.
abstract: High-performance liquid chromatography in conjunction with electrospray mass spectrometry (LC-ESMS) was used to structurally characterize the adducts formed by the platinum-acridine agent [PtCl(en)(N-(2-(acridin-9-ylamino)ethyl)-N-methylpropionimidamide)](NO(3))(2) (compound 1) in cell-free DNA. Compound 1 forms monofunctional adducts exclusively with guanine, based on the fragments identified in enzymatic digests (dG*, dGMP*, dApG*, and dTpG*, where the asterisk denotes bound drug). The time course of accumulation and DNA adduct formation of compound 1 and the clinical drug cisplatin in NCI-H460 lung cancer cells at physiologically relevant drug concentrations (0.1 μM) was studied by inductively-coupled plasma mass spectrometry (ICP-MS). Compound 1 accumulates rapidly in cells and reaches intracellular levels of up to 60-fold higher than those determined for cisplatin. The hybrid agent shows unusually high DNA binding levels: while cisplatin adducts form at a maximum frequency of 5 adducts per 10(6) nucleotides, compound 1 produces 25 adducts per 10(6) nucleotides after only 3 h of continuous incubation with the lung cancer cells. The high overall levels of compound 1 in the cells and in cellular DNA over the entire 12-h treatment period translate into a rapid decrease in cell viability. Possible implications of these findings for the mechanism of action of compound 1 and the agent's potential to overcome tumor resistance to cisplatin are discussed.
authors.affiliation: Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina 27109, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Qiao
authors.forename: Alexandra E
authors.initials: AE
authors.lastname: Zeitany
authors.forename: Marcus W
authors.initials: MW
authors.lastname: Wright
authors.forename: Amal S
authors.initials: AS
authors.lastname: Essader
authors.forename: Keith E
authors.initials: KE
authors.lastname: Levine
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Kucera
authors.forename: Ulrich
authors.initials: U
authors.lastname: Bierbach
mesh_terms: D000166:Acridines / Q000737:chemistry / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002474:Cell-Free System; D002851:Chromatography, High Pressure Liquid; D056148:Chromatography, Reverse-Phase; D002945:Cisplatin / Q000737:chemistry / Q000494:pharmacology; D018736:DNA Adducts / Q000737:chemistry / Q000378:metabolism; D004249:DNA Damage; D004273:DNA, Neoplasm / Q000378:metabolism; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D010984:Platinum / Q000737:chemistry / Q000494:pharmacology*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000166:Acridines; D000970:Antineoplastic Agents; D018736:DNA Adducts; D004273:DNA, Neoplasm; D010984:Platinum; D002945:Cisplatin