title: Nuphar lutea thioalkaloids inhibit the nuclear factor kappaB pathway, potentiate apoptosis and are synergistic with cisplatin and etoposide.
abstract: We screened thirty-four methanolic plant extracts for inhibition of the constitutive nuclear factor kappaB (NFkappaB) activity by a NFkappaB-luciferase reporter gene assay. Strong inhibition of NFkappaB activity was found in extracts of leaf and rhizome from Nuphar lutea L. SM. (Nuphar). The inhibitory action was narrowed down to a mixture of thionupharidines and/or thionuphlutidines that were identified in chromatography fractions by one- and two-dimensional NMR analysis. Dimeric sesquiterpene thioalkaloids were identified as the major components of the mixture. The Nuphar alkaloids mixture (NUP) showed a dose dependent inhibition of NFkappaB activity in a luciferase reporter gene assay as well as reduction of nuclear NFkappaB subunits expression as tested by western blots and immunohistochemistry. Decreased DNA binding was demonstrated in electro mobility shift assays. NUP inhibited both inducible and constitutive NFkappaB activation and affected the canonical and alternative pathways. Suppression of NFkappaB was not cell type specific. Induction of apoptosis by the alkaloid mixture was demonstrated by time-dependent and dose-dependent cleavage of procaspase-9 and PARP. Synergistic cytotoxicity of the active mixture with cisplatin and etoposide was demonstrated. Overall, our results show that NUP inhibits the NFkappaB pathway and acts as a sensitizer to conventional chemotherapy, enabling the search for its specific target and application against cancer and inflammation.
authors.affiliation: Dept. of Microbiology and Immunology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel.
authors.forename: Janet
authors.initials: J
authors.lastname: Ozer
authors.forename: Nadav
authors.initials: N
authors.lastname: Eisner
authors.forename: Elena
authors.initials: E
authors.lastname: Ostrozhenkova
authors.forename: Adelbert
authors.initials: A
authors.lastname: Bacher
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Eisenreich
authors.forename: Daniel
authors.initials: D
authors.lastname: Benharroch
authors.forename: Avi
authors.initials: A
authors.lastname: Golan-Goldhirsh
authors.forename: Jacob
authors.initials: J
authors.lastname: Gopas
mesh_terms: D000470:Alkaloids / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000008:administration & dosage / Q000494:pharmacology*; D004357:Drug Synergism; D005047:Etoposide / Q000008:administration & dosage / Q000494:pharmacology*; D006689:Hodgkin Disease / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D000432:Methanol / Q000737:chemistry; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000378:metabolism; D031654:Nuphar / Q000737:chemistry*; D010936:Plant Extracts / Q000008:administration & dosage / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D013438:Sulfhydryl Compounds / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: D000470:Alkaloids; D016328:NF-kappa B; D010936:Plant Extracts; D013438:Sulfhydryl Compounds; D005047:Etoposide; D002945:Cisplatin; D000432:Methanol