title: Antitumor agents. 1. Synthesis, biological evaluation, and molecular modeling of 5H-pyrido[3,2-a]phenoxazin-5-one, a compound with potent antiproliferative activity.
abstract: The iminoquinone is an important moiety of a large number of antineoplastic drugs and plays a significant role in the nucleus of actinomycins, powerful, highly toxic, natural antibiotics that target DNA as intercalating agents. A series of polycyclic iminoquinonic compounds, 2-amino-3H-phenoxazin-3-one (1), 2-amino-1,9-diacetyl-3H-phenoxazin-3-one (2), 2-acetylamino-3H-phenoxazin-3-one (3), 3H-phenoxazin-3-one (4), 5H-pyrido[3,2-a]phenoxazin-5-one (5), and 5H-pyrido[3,2-a]phenothiazin-5-one (6), strictly related to the actinomycin chromophore, were synthesized for developing new anticancer intercalating drugs. The antiproliferative activity of these compounds, evaluated against representative human liquid and solid neoplastic cell lines, showed that 5 and its isoster 6 were the most active compounds inhibiting cell proliferation in a submicromolar range. Compound 5 was also evaluated against KB subclones (KBMDR, KB7D, and KBV20C), which overexpress the MDR1/P-glycoprotein drug efflux pump responsible for drug resistance. All the above KB subclones did not show altered sensitivity to the antiproliferative activity of 5. UV-vis and (1)H NMR spectroscopy experiments support the phenoxazinone 5/DNA binding. Molecular mechanics methods were used to build a three-dimensional model of the 5/[d(GAAGCTTC)]2 complex. Electrostatic interactions between the hydrogen of the positively charged pyridine nitrogen of 5 and the negatively charged oxygen atoms (O4' and O5') of the cytosine C5 residue together with stacking forces contribute to the high antiproliferative activity. The metal(II)-assisted synthesis procedure of 5 is described, and the formation mechanism is proposed.
authors.affiliation: Dipartimento di Chimica Organica e Biochimica and Dipartimento di Chimica, Università di Napoli "Federico II", Via Cynthia 6, Monte Sant'Angelo, I-80126 Napoli, Italy. bologne@unina.it
authors.forename: Adele
authors.initials: A
authors.lastname: Bolognese
authors.forename: Gaetano
authors.initials: G
authors.lastname: Correale
authors.forename: Michele
authors.initials: M
authors.lastname: Manfra
authors.forename: Antonio
authors.initials: A
authors.lastname: Lavecchia
authors.forename: Orazio
authors.initials: O
authors.lastname: Mazzoni
authors.forename: Ettore
authors.initials: E
authors.lastname: Novellino
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Barone
authors.forename: Alessandra
authors.initials: A
authors.lastname: Pani
authors.forename: Enzo
authors.initials: E
authors.lastname: Tramontano
authors.forename: Paolo
authors.initials: P
authors.lastname: La Colla
authors.forename: Chiara
authors.initials: C
authors.lastname: Murgioni
authors.forename: Ilaria
authors.initials: I
authors.lastname: Serra
authors.forename: Giovanna
authors.initials: G
authors.lastname: Setzu
authors.forename: Roberta
authors.initials: R
authors.lastname: Loddo
mesh_terms: D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D004247:DNA / Q000737:chemistry; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D007364:Intercalating Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010078:Oxazines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D013056:Spectrophotometry, Ultraviolet; D013329:Structure-Activity Relationship; D013844:Thiazoles / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: C469559:5H-pyrido(3,2-a)phenoxazin-5-one; D000970:Antineoplastic Agents; D007364:Intercalating Agents; D010078:Oxazines; D013844:Thiazoles; D004247:DNA