title: Development of beta-lapachone prodrugs for therapy against human cancer cells with elevated NAD(P)H:quinone oxidoreductase 1 levels.
abstract: beta-Lapachone, an o-naphthoquinone, induces a novel caspase- and p53-independent apoptotic pathway dependent on NAD(P)H:quinone oxidoreductase 1 (NQO1). NQO1 reduces beta-lapachone to an unstable hydroquinone that rapidly undergoes a two-step oxidation back to the parent compound, perpetuating a futile redox cycle. A deficiency or inhibition of NQO1 rendered cells resistant to beta-lapachone. Thus, beta-lapachone has great potential for the treatment of specific cancers with elevated NQO1 levels (e.g., breast, non-small cell lung, pancreatic, colon, and prostate cancers). We report the development of mono(arylimino) derivatives of beta-lapachone as potential prodrugs. These derivatives are relatively nontoxic and not substrates for NQO1 when initially diluted in water. In solution, however, they undergo hydrolytic conversion to beta-lapachone at rates dependent on the electron-withdrawing strength of their substituent groups and pH of the diluent. NQO1 enzyme assays, UV-visible spectrophotometry, high-performance liquid chromatography-electrospray ionization-mass spectrometry, and nuclear magnetic resonance analyses confirmed and monitored conversion of each derivative to beta-lapachone. Once converted, beta-lapachone derivatives caused NQO1-dependent, mu-calpain-mediated cell death in human cancer cells identical to that caused by beta-lapachone. Interestingly, coadministration of N-acetyl-l-cysteine, prevented derivative-induced cytotoxicity but did not affect beta-lapachone lethality. Nuclear magnetic resonance analyses indicated that prevention of beta-lapachone derivative cytotoxicity was the result of direct modification of these derivatives by N-acetyl-l-cysteine, preventing their conversion to beta-lapachone. The use of beta-lapachone mono(arylimino) prodrug derivatives, or more specifically a derivative converted in a tumor-specific manner (i.e., in the acidic local environment of the tumor tissue), should reduce normal tissue toxicity while eliciting tumor-selective cell killing by NQO1 bioactivation.
authors.affiliation: Laboratory of Molecular Stress Responses, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Reinicke
authors.forename: Erik A
authors.initials: EA
authors.lastname: Bey
authors.forename: Melissa S
authors.initials: MS
authors.lastname: Bentle
authors.forename: John J
authors.initials: JJ
authors.lastname: Pink
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Ingalls
authors.forename: Charles L
authors.initials: CL
authors.lastname: Hoppel
authors.forename: Rosana I
authors.initials: RI
authors.lastname: Misico
authors.forename: Gisela M
authors.initials: GM
authors.lastname: Arzac
authors.forename: Gerardo
authors.initials: G
authors.lastname: Burton
authors.forename: William G
authors.initials: WG
authors.lastname: Bornmann
authors.forename: Damon
authors.initials: D
authors.lastname: Sutton
authors.forename: Jinming
authors.initials: J
authors.lastname: Gao
authors.forename: David A
authors.initials: DA
authors.lastname: Boothman
mesh_terms: D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000378:metabolism*; D009285:Naphthoquinones / Q000737:chemistry / Q000494:pharmacology*; D009369:Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology; D011355:Prodrugs / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet; D013329:Structure-Activity Relationship
chemical_list: D009285:Naphthoquinones; D011355:Prodrugs; C014638:beta-lapachone; D016660:NAD(P)H Dehydrogenase (Quinone); C447479:NQO1 protein, human