title: Effects of naringin on cytosine arabinoside (Ara-C)-induced cytotoxicity and apoptosis in P388 cells.
abstract: Naringin (NG), a flavonoid in grapefruit and citrus, has been reported to exhibit antioxidant effects and pharmacological actions. Recently, we have reported that NG suppressed the cytotoxicity and apoptosis induced by H(2)O(2), a typical pro-oxidant, in mouse leukemia P388 cells. Cytosine arabinoside (1-beta-d-arabinofuranosylcytosine; Ara-C) is the most important antimetabolite chemotherapeutic drug used for acute leukemia. It has been suggested that Ara-C-induced cytotoxicity is caused by apoptosis, which is mediated by reactive oxygen species (ROS). In this study, we examined the effect of NG on the cytotoxicity and apoptosis in mouse leukemia P388 cells treated with Ara-C. Ara-C caused cytotoxicity in a concentration and time-dependent manner in the cells. N-Acetyl-L-cysteine (NAC), cystamine (CysA) or a reduced form of glutathione (GSH), typical antioxidants significantly blocked Ara-C-induced cytotoxicity. Similarly, Ara-C-induced cell death was completely prevented by NG. NG strongly reduced ROS production caused by Ara-C in the cells. NG slightly increased the activities of antioxidant enzymes, catalase and glutathione peroxidase. Ara-C caused apoptosis with nuclear morphological change and DNA fragmentation. NG remarkably attenuated the Ara-C-induced apoptosis. NG completely blocked the DNA damage caused by Ara-C treatment at 6 h using the Comet assay. Our data suggest that NG reduces Ara-C-induced oxidative stress through both an inhibition of the generation of ROS production and an increase in antioxidant enzyme activities. Consequently, NG blocked apoptosis caused by Ara-C-induced oxidative stress, resulting in the inhibition of the cytotoxicity of Ara-C.
authors.affiliation: Department of Pharmacology and Toxicology, Cancer Research Institute, Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba, Sendai 981-8558, Japan. syu-kan@tohoku-pharm.ac.jp
authors.forename: Syu-Ichi
authors.initials: S
authors.lastname: Kanno
authors.forename: Ai
authors.initials: A
authors.lastname: Shouji
authors.forename: Riki
authors.initials: R
authors.lastname: Hirata
authors.forename: Keiko
authors.initials: K
authors.lastname: Asou
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ishikawa
mesh_terms: D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002374:Catalase / Q000096:biosynthesis; D002467:Cell Nucleus / Q000187:drug effects / Q000648:ultrastructure; D020552:Comet Assay; D003561:Cytarabine / Q000494:pharmacology*; D053938:DNA Fragmentation / Q000187:drug effects; D044950:Flavanones / Q000494:pharmacology*; D005979:Glutathione Peroxidase / Q000096:biosynthesis; D007941:Leukemia P388 / Q000188:drug therapy* / Q000473:pathology; D051379:Mice; D008856:Microscopy, Fluorescence; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase / Q000096:biosynthesis; D013778:Tetrazolium Salts; D013844:Thiazoles
chemical_list: D000964:Antimetabolites, Antineoplastic; D000975:Antioxidants; D044950:Flavanones; D017382:Reactive Oxygen Species; D013778:Tetrazolium Salts; D013844:Thiazoles; D003561:Cytarabine; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; C022616:thiazolyl blue; C005274:naringin