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Acetaminophen potentiates staurosporine-induced death in a human neuroblastoma cell line.

ABSTRACT: BACKGROUND AND PURPOSE: Neuroblastoma is the most common solid tumour in infants characterized by a high resistance to apoptosis. Recently, the cyclo-oxygenase pathway has been considered a potential target in the treatment of different kinds of tumours. The aim of the present work was to investigate a possible relationship between cyclo-oxygenase pathway and stauroporine-induced apoptosis in the neuroblastoma cell line SH-SY5Y. EXPERIMENTAL APPROACH: Cellular viability was measured by release of LDH. DNA fragmentation was visualized by electrophoresis on agarose gel containing ethidium bromide. Cyclo-oxygenase activity was measured in microsomal fractions obtained from cells by quantification of its final product PGE2 by RIA. Caspase-3 activity was measured fluorimetrically and Western blot analysis was performed to assess cytochrome c expression. KEY RESULTS: We have found that staurosporine (500 nM) induced cellular death in a time-dependent manner in SH-SY5Y human neuroblastoma cells. Cyclo-oxygenase enzymatic activity was present in SH-SY5Y human neuroblastoma cells under basal conditions and pharmacological experiments using COX inhibitors indicate that cyclo-oxygenase-1 and cyclo-oxygenase-3 are the active isoforms in these cells. Co-incubation of SH-SY5Y cells with staurosporine (500 nM) and acetaminophen for 24 h potentiated staurosporine-mediated cellular death in a concentration-dependent manner. This process is mediated by an increase in cytochrome c release and caspase 3 activation and is prevented by N-acetylcysteine or the superoxide dismutase mimetic, MnTBAP. CONCLUSIONS AND IMPLICATIONS: Acetaminophen potentiates staurosporine-mediated neuroblastoma cell death. The mechanism of action of acetaminophen seems to be related to production of reactive oxygen species and decreased intracellular glutathione levels.

SUBMITTER: Posadas I

PROVIDER: S-EPMC2189768 | biostudies-other | 2007 Mar

REPOSITORIES: biostudies-other

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Project description:Acetaminophen (APAP) is a safe analgesic antipyretic drug at prescribed doses. Its overdose, however, can cause life-threatening liver damage. Though, involvement of oxidative stress is widely acknowledged in APAP-induced hepatocellular death, the mechanism of this increased oxidative stress and the associated alterations in Ca(2+) homeostasis are still unclear. Among members of transient receptor potential (TRP) channels activated in response to oxidative stress, we here identify that redox-sensitive TRPV1, TRPC1, TRPM2, and TRPM7 channels underlie Ca(2+) entry and downstream cellular damages induced by APAP in human hepatoma (HepG2) cells. Our data indicate that APAP treatment of HepG2 cells resulted in increased reactive oxygen species (ROS) production, glutathione (GSH) depletion, and Ca(2+) entry leading to increased apoptotic cell death. These responses were significantly suppressed by pretreatment with the ROS scavengers N-acetyl-L-cysteine (NAC) and 4,5-dihydroxy-1,3-benzene disulfonic acid disodium salt monohydrate (Tiron), and also by preincubation of cells with the glutathione inducer Dimethylfumarate (DMF). TRP subtype-targeted pharmacological blockers and siRNAs strategy revealed that suppression of either TRPV1, TRPC1, TRPM2, or TRPM7 reduced APAP-induced ROS formation, Ca(2+) influx, and cell death; the effects of suppression of TRPV1 or TRPC1, known to be activated by oxidative cysteine modifications, were stronger than those of TRPM2 or TRPM7. Interestingly, TRPV1 and TRPC1 were labeled by the cysteine-selective modification reagent, 5,5'-dithiobis (2-nitrobenzoic acid)-2biotin (DTNB-2Bio), and this was attenuated by pretreatment with APAP, suggesting that APAP and/or its oxidized metabolites act directly on the modification target cysteine residues of TRPV1 and TRPC1 proteins. In human liver tissue, TRPV1, TRPC1, TRPM2, and TRPM7 channels transcripts were localized mainly to hepatocytes and Kupffer cells. Our findings strongly suggest that APAP-induced Ca(2+) entry and subsequent hepatocellular death are regulated by multiple redox-activated cation channels, among which TRPV1 and TRPC1 play a prominent role.