Indomethacin impairs mitochondrial dynamics by activating the PKCζ–p38–DRP1 pathway and inducing apoptosis in gastric cancer and normal mucosal cells

Abstract

The subcellular mechanism by which nonsteroidal anti-inflammatory drugs (NSAIDs) induce apoptosis in gastric cancer and normal mucosal cells is elusive because of the diverse cyclooxygenase-independent effects of these drugs. Using human gastric carcinoma cells (AGSs) and a rat gastric injury model, here we report that the NSAID indomethacin activates the protein kinase Cζ (PKCζ)–p38 MAPK (p38)–dynamin-related protein 1 (DRP1) pathway and thereby disrupts the physiological balance of mitochondrial dynamics by promoting mitochondrial hyper-fission and dysfunction leading to apoptosis. Notably, DRP1 knockdown or SB203580-induced p38 inhibition reduced indomethacin-induced damage to AGSs. Indomethacin impaired mitochondrial dynamics by promoting fissogenic activation and mitochondrial recruitment of DRP1 and down-regulating fusogenic optic atrophy 1 (OPA1) and mitofusins in rat gastric mucosa. Consistent with OPA1 maintaining cristae architecture, its down-regulation resulted in EM-detectable cristae deformity. Deregulated mitochondrial dynamics resulting in defective mitochondria were evident from enhanced Parkin expression and mitochondrial proteome ubiquitination. Indomethacin ultimately induced mitochondrial metabolic and bioenergetic crises in the rat stomach, indicated by compromised fatty acid oxidation, reduced complex I– associated electron transport chain activity, and ATP depletion. Interestingly, Mdivi-1, a fission-preventing mito-protective drug, reversed indomethacin-induced DRP1 phosphorylation on Ser-616, mitochondrial proteome ubiquitination, and mitochondrial metabolic crisis. Mdivi-1 also prevented indomethacin-induced mitochondrial macromolecular damage, caspase activation, mucosal inflammation, and gastric mucosal injury. Our results identify mitochondrial hyper-fission as a critical and common subcellular event triggered by indomethacin that promotes apoptosis in both gastric cancer and normal mucosal cells, thereby contributing to mucosal injury.

The prospective curative role of lipoxin A4 in induced gastric ulcer in rats: Possible involvement of mitochondrial dynamics signaling pathway

“…IND administration promoted a state of mitochondrial hyperfission as confirmed, in these results, by significant increase of Drp1 expression with significant decrease of Mfn2 expression. This was matched with a previous study showed that IND enhanced mitochondrial Drp1 . It was observed, in our results, that LXA 4 treatment significantly corrected the mitochondrial imbalance as established by significant decrease of the mitochondrial Drp1 expression and increase of Mfn2 expression.…”

“…This was consistent with previous reports . The apoptosis caused by IND might be explained by its effect on mitochondrial dynamics with subsequent increase of oxidative stress, or explained by the mitochondrial ROS generation that leads to cell death and apoptosis . It was reported that increased mitochondrial imbalance, hyperfission, and oxidative stress lead to activation of apoptotic pathways .…”

“…As shown in the results of this work, IND impaired some mitochondrial functions, as evidenced by significant reduction of ΔΨm, ETC complex‐I with concomitant elevation of mitochondrial ROS. These results were concurrent with other previous researches . Mitochondria are considered main source of ROS production with subsequent oxidative stress and apoptosis in the gastric mucosa …”

“…Also, it has been reported that NSAIDs might cause apoptosis of the gastric mucosa . A previous study has been demonstrated that NSAIDs can cause damage of the gastric mucosa via alteration of the mitochondrial dynamics with subsequent stimulation of mitochondrial hyperfission …”

Endoplasmic Reticulum Stress Contributes to Indomethacin-Induced Glioma Apoptosis

“…Nonselective COX inhibitor indomethacin has a profound pro-apoptotic effect on malignancy through ER stress, mitogen-activated protein kinase (MAPK), Akt, β-catenin, C/EBP Homologous Protein (CHOP), AMP-activated protein kinase (AMPK), or Aurora B kinase [19][20][21][22][23]. Findings of in vitro and in vivo studies further indicate the anti-neoplastic effects of indomethacin against glioma, involving growth inhibition, differentiation, and apoptosis [21,[24][25][26][27][28][29].…”