scholarly journals Nur77 promotes cigarette smoke‑induced autophagic cell death by increasing the dissociation of Bcl2 from Beclin-1

Author(s):  
Huiping Qin ◽  
Feng Gao ◽  
Yanni Wang ◽  
Bin Huang ◽  
Ling Peng ◽  
...  
Author(s):  
Tae Woo Kim

AbstractPrevious reports suggested that cinnamaldehyde (CA), the bioactive ingredient in Cinnamomum cassia, can suppress tumor growth, migratory, and invasive abilities. However, the role and molecular mechanisms of CA in GC are not completely understood. In the present study, we found that CA-induced ER stress and cell death via the PERK–CHOP axis and Ca2+ release in GC cells. Inhibition of ER stress using specific–siRNA blocked CA-induced cell death. Interestingly, CA treatment resulted in autophagic cell death by inducing Beclin-1, ATG5, and LC3B expression and by inhibiting p62 expression whereas autophagy inhibition suppressed CA-induced cell death. We showed that CA induces the inhibition of G9a and the activation of LC3B. Moreover, CA inhibited G9a binding on Beclin-1 and LC3B promoter. Overall, these results suggested that CA regulates the PERK–CHOP signaling, and G9a inhibition activates autophagic cell death via ER stress in GC cells.


2016 ◽  
Vol 38 (3) ◽  
pp. 1063-1074 ◽  
Author(s):  
Jin Fan ◽  
Yuwen Liu ◽  
Jian Yin ◽  
Qingqing Li ◽  
Yiming Li ◽  
...  

Background/Aims: The purpose of this study was to investigate the role of autophagy in oxygen-glucose-deprivation/reoxygenation (OGD/R) injury in rat neurons. Methods and results: Cortical neurons were isolated from Sprague-Dawley rats and identified by immunofluorescence. The cortical neurons were randomly assigned to one of four groups: control group (I), experimental group (OGD/R group, II), JNK inhibitor pretreatment group (III) and JNK inhibitor pretreatment + OGD/R group (IV). Neuronal cell viability significantly decreased after 6h and 12h of reoxygenation in Group IV (P < 0.05). Electron microscopy showed the presence of many autophagic vacuoles and the formation of autolysosomes in the neurons; the number of autophagic vacuoles decreased transiently at 6h, while a new autophagic flux and a large number of empty autophagic vacuoles were observed at 12h. In Group IV, a large number of autophagic vacuoles were present at 0.5h and 2h of reoxygenation, which gradually decreased with increasing reoxygenation time. No significant differences in the expression of the LC3II protein were detected between the Group II and IV prior to 6h of reoxygenation, and LC3II expression showed an overall rise-decline pattern. However, LC3II protein expression increased in Group II at 12h of reoxygenation, whereas a continuous decline was observed in Group IV. The levels of phosphorylated JNK and Bcl-2 and the expression of Beclin-1 increased gradually as the reoxygenation time going in Group II, whereas they increased at 12h of reoxygenation in Group IV (P < 0.05). In addition, progressive dissociation of the Bcl-2/Beclin-1 complex was observed in the Group II, while JNK inhibitor suppressed this dissociation. Conclusion: The regulation of the JNK/Bcl-2/Beclin-1 signaling pathway may be one of the mechanisms underlying the OGD/R-induced autophagic cell death of neurons.


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