title: Rapid generation of hydrogen peroxide contributes to the complex cell death induction by the angucycline antibiotic landomycin E.
abstract: Landomycin E (LE) is an angucycline antibiotic produced by Streptomyces globisporus. Previously, we have shown a broad anticancer activity of LE which is, in contrast to the structurally related and clinically used anthracycline doxorubicin (Dx), only mildly affected by multidrug resistance-mediated drug efflux. In the present study, cellular and molecular mechanisms underlying the anticancer activity of landomycin E towards Jurkat T-cell leukemia cells were dissected focusing on the involvement of radical oxygen species (ROS). LE-induced apoptosis distinctly differed in several aspects from the one induced by Dx. Rapid generation of both extracellular and cell-derived hydrogen peroxide already at one hour drug exposure was observed in case of LE but not found before 24h for Dx. In contrast, Dx but not LE induced production of superoxide radicals. Mitochondrial damage, as revealed by JC-1 staining, was weakly enhanced already at 3h LE treatment and increased significantly with time. Accordingly, activation of the intrinsic apoptosis pathway initiator caspase-9 was not detectable before 12h exposure. In contrast, cleavage of the down-stream caspase substrate PARP-1 was clearly induced already at the three hour time point. Out of all caspases tested, only activation of effector caspase-7 was induced at this early time points paralleling the LE-induced oxidative burst. Accordingly, this massive cleavage of caspase-7 at early time points was inhibitable by the radical scavenger N-acetylcysteine (NAC). Additionally, only simultaneous inhibition of multiple caspases reduced LE-induced apoptosis. Specific scavengers of both H2O2and OH•effectively decreased LE-induced ROS production, but only partially inhibited LE-induced apoptosis. In contrast, NAC efficiently blocked both parameters. Summarizing, rapid H2O2generation and a complex caspase activation pattern contribute to the antileukemic effects of LE. As superoxide generation is considered as the main cardiotoxic mechanism of Dx, LE might represent a better tolerable drug candidate for further (pre)clinical development.
authors.affiliation: Institute of Cell Biology NAS of Ukraine, Lviv, Ukraine.
authors.forename: Rostyslav R
authors.initials: RR
authors.lastname: Panchuk
authors.affiliation: Institute of Cell Biology NAS of Ukraine, Lviv, Ukraine.
authors.forename: Lilya V
authors.initials: LV
authors.lastname: Lehka
authors.affiliation: Institute of Inorganic Chemistry, University of Vienna, Vienna, Austria.
authors.forename: Alessio
authors.initials: A
authors.lastname: Terenzi
authors.affiliation: D.K. Zabolotny Institute of Microbiology and Virology NAS of Ukraine, Lviv, Ukaine.
authors.forename: Bohdan P
authors.initials: BP
authors.lastname: Matselyukh
authors.affiliation: University of Kentucky, College of Pharmacy, Lexington, USA.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rohr
authors.affiliation: University of Kentucky, College of Pharmacy, Lexington, USA.
authors.forename: Amit K
authors.initials: AK
authors.lastname: Jha
authors.affiliation: University of Kentucky, College of Pharmacy, Lexington, USA.
authors.forename: Theresa
authors.initials: T
authors.lastname: Downey
authors.affiliation: Danylo Halytsky Lviv National Medical University, Lviv, Ukraine.
authors.forename: Iryna J
authors.initials: IJ
authors.lastname: Kril
authors.affiliation: Institute of Cancer Research and Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria.
authors.forename: Irene
authors.initials: I
authors.lastname: Herbacek
authors.affiliation: Institute of Cancer Research and Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria.
authors.forename: Sushilla
authors.initials: S
authors.lastname: van Schoonhoven
authors.affiliation: Institute of Cancer Research and Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria.
authors.forename: Petra
authors.initials: P
authors.lastname: Heffeter
authors.affiliation: Institute of Cell Biology NAS of Ukraine, Lviv, Ukraine. Electronic address: stoika@cellbiol.lviv.ua.
authors.forename: Rostyslav S
authors.initials: RS
authors.lastname: Stoika
authors.affiliation: Institute of Cancer Research and Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria. Electronic address: walter.berger@meduniwien.ac.at.
authors.forename: Walter
authors.initials: W
authors.lastname: Berger
mesh_terms: D000111:Acetylcysteine / Q000008:administration & dosage; D000617:Aminoglycosides / Q000008:administration & dosage*; D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage*; D017209:Apoptosis / Q000187:drug effects; D053179:Caspase 7 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D004317:Doxorubicin / Q000008:administration & dosage; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D019169:Jurkat Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D007938:Leukemia / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008928:Mitochondria / Q000187:drug effects / Q000473:pathology; D018384:Oxidative Stress / Q000187:drug effects*; D000071137:Poly (ADP-Ribose) Polymerase-1 / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013302:Streptomyces / Q000737:chemistry; D013481:Superoxides / Q000633:toxicity
chemical_list: D000617:Aminoglycosides; D000903:Antibiotics, Antineoplastic; D017382:Reactive Oxygen Species; C113593:landomycin E; D013481:Superoxides; D004317:Doxorubicin; D006861:Hydrogen Peroxide; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D053179:Caspase 7; D053453:Caspase 9; D000111:Acetylcysteine
keywords: Anticancer drugs; Apoptosis; Hydrogen peroxide; Landomycin E; Multi-drug resistance; N-acetylcysteine; Reactive oxygen species; Superoxide radicals