Diclofenac-Induced Apoptosis in the Neuroblastoma Cell Line SH-SY5Y: Possible Involvement of the Mitochondrial Superoxide Dismutase

Francesca Cecere,Mariorosario Masullo,Pasquale Grimaldi,Immacolata Castellano,Claudia Zappelli,Emmanuele De Vendittis,Francesco Albano,Maria Rosaria Ruocco,Annarita Iuliano

doi:10.1155/2010/801726

Abstract

Diclofenac, a nonsteroidal anti-inflammatory drug, induces apoptosis on the neuroblastoma cell line SH-SY5Y through a mitochondrial dysfunction, affecting some antioxidant mechanisms. Indeed, the time- and dose-dependent increase of apoptosis is associated to an early enhancement of the reactive oxygen species (ROS). Mitochondrial superoxide dismutase (SOD2) plays a crucial role in the defence against ROS, thus protecting against several apoptotic stimuli. Diclofenac decreased the protein levels and the enzymatic activity of SOD2, without any significant impairment of the corresponding mRNA levels in the SH-SY5Y extracts. When cells were incubated with an archaeal exogenous thioredoxin, an attenuation of the diclofenac-induced apoptosis was observed, together with an increase of SOD2 protein levels. Furthermore, diclofenac impaired the mitochondrial membrane potential, leading to a release of cytochrome c. These data suggest that mitochondria are involved in the diclofenac-induced apoptosis of SH-SY5Y cells and point to a possible role of SOD2 in this process.

Highlights

Reactive oxygen species (ROS), normally produced during the aerobic metabolism, function as second messengers involved in many cellular functions
In this paper we describe the effects of diclofenac on cultures of the neuroblastoma cell line SH-SY5Y, extending to this neuronal cell our knowledge on the possible toxicity of this drug, already reported for gastric, hepatic, or renal cells
We present evidence that diclofenac induces apoptosis through a modulation of the mitochondrial function, associated to an alteration of the redox homeostasis

Summary

Introduction

Reactive oxygen species (ROS), normally produced during the aerobic metabolism, function as second messengers involved in many cellular functions. On the other hand, when ROS level increases because of oxidant treatments and/or defective antioxidant systems, these highly reactive compounds and radicals become dangerous toxic agents. Diclofenac, a nonsteroidal anti-inflammatory drug (NSAID) widely used in clinical therapeutics, has cytotoxic effects and induces apoptosis in many cultured cell lines [3, 4]. This behaviour is common even to other NSAIDs and some anticancer agents. ROS are involved in the diclofenac-induced apoptosis of cultured gastric cells as well as in nephrotoxicity in vivo [9, 10]; an oxidative injury causes the mitochondrial permeability transition in diclofenac-treated hepatocytes [11]. The molecular mechanisms underlying the induction of apoptosis by diclofenac have not been clarified in neuronal cells

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