Ca²⁺‐independent caspase‐3 but not Ca²⁺‐dependent caspase‐2 activation induced by oxidative stress leads to SH‐SY5Y human neuroblastoma cell apoptosis

Abstract

Continuous and long-lasting exposure to tert-butylhydroperoxide (t-BOOH) increased the number of apoptotic SH-SY5Y human neuroblastoma cells both in the presence and in the absence of the intracellular Ca(2+) ion chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA). In addition, t-BOOH exposure induced activation of CPP32, as demonstrated by poly-(ADP-ribose) polymerase (PARP) cleavage, and of ICH-1L caspases. Exposure to t-BOOH also induced a time-dependent release of cytochrome c. Interestingly, in the presence of BAPTA, CPP32 activation still occurred, whereas ICH-1L activation was blocked. Ac-DEVD-CHO, an inhibitor of CPP32 activity, prevented the appearance of apoptotic cells, whereas the inhibitor of ICH-1L activity Z-VDVAD-FMK did not. Collectively, these findings demonstrate that in SH-SY5Y neuroblastoma cells exposure to continuous and long-lasting oxidative stress induced activation of caspase-3 that was independent of intracellular Ca(2+) ion concentration ([Ca(2+)](i)) elevation but led to cell apoptosis. In contrast, caspase-2 activation was dependent on [Ca(2+)](i) increase but did not result in apoptosis.

Up-Regulation and Increased Activity of KV3.4 Channels and Their Accessory Subunit MinK-Related Peptide 2 Induced by Amyloid Peptide Are Involved in Apoptotic Neuronal Death

“…These findings are in accordance with other experiments carried out with rhodaminate-phalloidin, a selective actin fluorescence staining, which revealed that A␤ 1-42 causes a cytoskeletal rearrangement (Pannaccione et al, 2005). In addition, hippocampal neurons and NGF-differentiated PC-12 cells expressing increased K V 3.4 immunoreactivity showed an apoptotic nuclear process, as revealed by caspase-3 activation (Amoroso et al, 2002;Tamagno et al, 2006) and by Hoechst 33258-monitored abnormal nuclear morphology, thus suggesting a possible link between the enhanced expression and function of this K ϩ channel and the neurotoxic consequences prompted by A␤ exposure. That the exposure to A␤ fragments may alter the properties of K ϩ currents in mammalian neurons (Jalonen et al, 1997;Colom et al, 1998;Yu et al, 1998;Jhamandas et al, 2001;Ramsden et al, 2001;Pannaccione et al, 2005) and therefore may cause an increase in cell death as a result of a decrease in cytoplasmic K ϩ concentrations (Bortner et al, 1997;Hughes and Cidlowski, 1999) has already been reported.…”

“…Cells were washed in PBS and collected by gentle scraping in ice-cold lysis buffer to detect K V 3.4, K V 3.3, and MIRP2 proteins (Secondo et al, 2003) or immunoprecipitation assay buffer to detect caspase-3 protein expressions (Amoroso et al, 2002). Both lysis buffers contained Protease Inhibitor Cocktail II (Roche Diagnostics, Monza, Italy).…”

Tryptanthrin Protects Hepatocytes against Oxidative Stress <i>via</i> Activation of the Extracellular Signal-Regulated Kinase/NF-E2-Related Factor 2 Pathway

“…tBHP is frequently employed as an oxidative stress inducer, which induces damage to lipids and DNA. 3,4) In this study, tBHP caused apoptotic death in hepatocytes through dysfunction of MMP and ROS production. However, pre-treatment with tryptanthrin inhibited tBHPinduced cell death, alteration of MMP, and production of ROS.…”

“…3,4) Therefore, the effects of tryptanthrin on tBHP-induced cytotoxicity were examined in this study. MTT assay was conducted to test whether or not tryptanthrin prevents tBHP-mediated cytotoxicity.…”

Melatonin attenuates apoptosis and mitochondrial depolarization levels in hypoxic conditions of SH-SY5Y neuronal cells induced by cobalt chloride (CoCl2)

“…In addition to these results regarding oxidative stress findings, apoptosis seemed to occur concomitantly. After these studies, Amoroso et al (2002) determined that t-BOOH, an oxidative stress inducer, triggered caspase-2 and -3 activation in SH-SY5Y neuronal cells. Our findings also support these data; we determined that oxidative stress triggered caspase-3 and -9 activation in SH-SY5Y neuronal cells.…”