scholarly journals Receptor-interacting Protein 1 Increases Chemoresistance by Maintaining Inhibitor of Apoptosis Protein Levels and Reducing Reactive Oxygen Species through a microRNA-146a-mediated Catalase Pathway

2014 ◽  
Vol 289 (9) ◽  
pp. 5654-5663 ◽  
Author(s):  
Qiong Wang ◽  
Wenshu Chen ◽  
Lang Bai ◽  
Wenjie Chen ◽  
Mabel T. Padilla ◽  
...  
2021 ◽  
Vol 20 (1) ◽  
pp. 76-83
Author(s):  
Chi-Sen Chang ◽  
Yuh-Chiang Shen ◽  
Chi-Wen Juan ◽  
Chia-Lin Chang ◽  
Po-Kai Lin

The neuroprotective mechanisms of Crataegus pinnatifida extracts and crataegolic acid were studied using paraquat induced cytotoxicity in PC12 cells. C. pinnatifida extracts were prepared using hexane, ethyl acetate, and 95% ethanol. Additionally, crataegolic acid (also known as maslinic acid) was found in C. pinnatifida extracts. Assessment methods included the examinations of cytotoxicity, intracellular reactive oxygen species and calcium changes, activity of caspase-3 and α-synuclein, apoptotic cell death, and the expression levels of the B-cell lymphoma 2 (Bcl-2) and BCL2-associated X (Bax) proteins to investigate the neuroprotective mechanisms of C. pinnatifida extracts and its active component, crataegolic acid. The three extracts and crataegolic acid exhibited potent neuroprotective actions against paraquat induced PC12 cell apoptosis at 5–20µg/mL and 80–100µM concentrations, respectively. The key protective mechanisms included decreasing cell apoptosis, upregulating Bcl-2 protein levels, and downregulating Bax protein levels. The 95% ethanol extract also decreased paraquat induced reactive oxygen species production, calcium overloading, and caspase-3 and α-synuclein activities. The beneficial effects of these extracts could be explained by the active component, crataegolic acid that also inhibited paraquat-induced apoptosis through the suppression of reactive oxygen species generation and the caspase-3 signaling pathway.


Author(s):  
Li Hu ◽  
Li-Li Li ◽  
Zhi-Guo Lin ◽  
Zhi-Chao Jiang ◽  
Hong-Xing Li ◽  
...  

The potassium (K+) channel plays an important role in the cell cycle and proliferation of tumor cells, while its role in brain glioma cells and the signaling pathways remains unclear. We used tetraethylammonium (TEA), a nonselective antagonist of big conductance K+ channels, to block K+ channels in glioma cells, and antioxidant N-acetyl-l-cysteine (NAC) to inhibit production of intracellular reactive oxygen species (ROS). TEA showed an antiproliferation effect on C6 and U87 glioma cells in a time-dependent manner, which was accompanied by an increased intracellular ROS level. Antioxidant NAC pretreatment reversed TEA-mediated antiproliferation and restored ROS level. TEA treatment also caused significant increases in mRNA and protein levels of tumor-suppressor proteins p53 and p21, and the upregulation was attenuated by pretreatment of NAC. Our results suggest that K+ channel activity significantly contributes to brain glioma cell proliferation via increasing ROS, and it might be an upstream factor triggering the activation of the p53/p21Cip1-dependent signaling pathway, consequently leading to glioma cell cycle arrest.


Antioxidants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 773
Author(s):  
Maribel Escoll ◽  
Diego Lastra ◽  
Natalia Robledinos-Antón ◽  
Francisco Wandosell ◽  
Inés María Antón ◽  
...  

Due to their high metabolic rate, tumor cells produce exacerbated levels of reactive oxygen species that need to be under control. Wiskott–Aldrich syndrome protein (WASP)-interacting protein (WIP) is a scaffold protein with multiple yet poorly understood functions that participates in tumor progression and promotes cancer cell survival. However, its participation in the control of oxidative stress has not been addressed yet. We show that WIP depletion increases the levels of reactive oxygen species and reduces the levels of transcription factor NRF2, the master regulator of redox homeostasis. We found that WIP stabilizes NRF2 by restraining the activity of its main NRF2 repressor, the E3 ligase adapter KEAP1, because the overexpression of a NRF2ΔETGE mutant that is resistant to targeted proteasome degradation by KEAP1 or the knock-down of KEAP1 maintains NRF2 levels in the absence of WIP. Mechanistically, we show that the increased KEAP1 activity in WIP-depleted cells is not due to the protection of KEAP1 from autophagic degradation, but is dependent on the organization of the Actin cytoskeleton, probably through binding between KEAP1 and F-Actin. Our study provides a new role of WIP in maintaining the oxidant tolerance of cancer cells that may have therapeutic implications.


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