Nutrient deprivation induces autophagy as well as apoptosis in Chinese hamster ovary cell culture

Hwang, Sun Ok; Lee, Gyun Min

doi:10.1002/bit.21589

Cited by 103 publications

(101 citation statements)

References 52 publications

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“…8 In addition, a protective role of autophagy has been reported in a model of TBI (specifically closedhead injury) in mice 16 and under conditions of nutrient depletion in cell culture. 23 In cardiac myocytes, enhancing autophagy was seen to protect against ischemia/reperfusion injury, 20 while in neonatal cerebral ischemia, inhibition of autophagy strongly reduced the lesion volume (by 46%), 49 similar to results reported in other studies. 10,49 In our autophagy model, we detected colocalization of neuronal and astrocyte markers with activated caspase-3, which is an inducer of apoptosis.…”

Section: Discussionsupporting

confidence: 83%

Acute spinal cord injury in rats should target activated autophagy

Hou

Zhang

Tang

2014

SPI

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Object Autophagy is a cellular mechanism of maintaining balance between protein synthesis and degradation; the latter can be induced by starvation and neurodegenerative disease. Spinal cord injury (SCI) induces necrosis and apoptosis. Autophagic flux has not yet been defined, especially the potential role of autophagy in relation to apoptosis in different tissue cells. The object of this study was to investigate the occurrence of autophagic flux and the potential role of autophagy and apoptosis post-SCI in rats. Methods Following creation of SCI in rats, activation of autophagic flux was detected at the protein (LC3, beclin1, and p62) and mRNA (beclin1) levels and on electron microscopy images. Distribution of LC3, colocalization of activated caspase-3, and changes in expression levels of bcl-2 and Bax were assessed to investigate the potential role of autophagy and apoptosis. Sprague-Dawley rats were used, and T9–10 hemitransection was performed. Expression levels of LC3, beclin1, p62, bcl-2, and Bax were assessed by Western blot analysis, and beclin1 mRNA levels were assessed by reverse transcription–polymerase chain reaction. Distribution of LC3 and colocalization of activated caspase-3 were analyzed by immunohistochemistry. Autophagosome formation was investigated by electron microscopy. Results The authors found a dramatic elevation in LC3 and beclin1 levels near the scar region. Using double staining, they observed that upregulation of LC3 started at 4 hours in neurons and at 3 days in astrocytes after SCI. Confocal images indicated that the percentage of neurons with apoptosis was reduced, while the percentage of astrocytes with apoptosis was high at 4 hours, 8 hours, and 1 day post-SCI but decreased sharply at 3 days. Electron microscopy images provided evidence of autophagosome formation. Elimination of p62 indicated occurrence of autophagic flux. Expression levels of bcl-2 and Bax were increased and decreased, respectively, near the injury site. Conclusions The results of this research demonstrated that autophagic flux is activated after SCI. Potentially, inhibition of apoptosis could be a target to promote neural recovery.

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Section: Discussionsupporting

confidence: 83%

Acute spinal cord injury in rats should target activated autophagy

Hou

Zhang

Tang

2014

SPI

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“…Taken together, these observations are in line with the concept suggested by Robey and Hay (2006). In addition to the potential role of mitochondria, evidence suggesting the involvement of the mTOR/S6K1 pathway in the induction of cell death upon glucose withdrawal has been reported (Hwang and Lee, 2008). Finally, deprivation of branched chain-amino acids (BCAA), but also of other amino acids (AA)), exerted a pro-apoptotic activity on HCC-1.2 cells; AAdeprivation and TGF-␤1 appear to act additively (Mayer et al, 2007).…”

Section: Autophagy: Response To Metabolic Challenges Link To Nutritisupporting

confidence: 89%

“…Glucose deprived medium is equivalent to RPMI1640 without glucose addition; a stock solution of 2-deoxyglucose (500 mM, Sigma D8375) was prepared in RPIMI1640 medium without glucose and added directly to the culture dish to obtain the final concentrations as indicated in the figure. reported to be induced in cardiomyocyte-derived H9c2 cells, human hepatoma cells (HepG2) and Chinese hamster-ovary (CHO)-derived cells (Aki et al, 2003;Byfield et al, 2005). Notably, death of CHO-cells triggered by glucose deprivation may result in autophagic as well as apoptotic pathways (Hwang and Lee, 2008).…”

Section: Autophagy: Response To Metabolic Challenges Link To Nutritimentioning

confidence: 99%

Cell death and autophagy: Cytokines, drugs, and nutritional factors

Bursch¹,

Karwan²,

Mayer³

et al. 2008

Toxicology

119

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Cells may use multiple pathways to commit suicide. In certain contexts, dying cells generate large amounts of autophagic vacuoles and clear large proportions of their cytoplasm, before they finally die, as exemplified by the treatment of human mammary carcinoma cells with the anti-estrogen tamoxifen (TAM, <= 1 mu M). Protein analysis during autophagic cell death revealed distinct proteins of the nuclear fraction including CST-pi and some proteasomal subunit constituents to be affected during autophagic cell death. Depending on the functional status of caspase-3, MCF-7 cells may switch between autophagic and apoptotic features of cell death [Fazi, B., Bursch, W., Fimia, G.M., Nardacci R., Piacentini, M., Di Sano, F., Piredda. L., 2008. Fenretinide induces autophagic cell death in caspase-defective breast cancer cells. Autophagy 4(4), 435-441]. Furthermore, the self-destruction of MCF-7 cells was found to be completed by phagocytosis of cell residues [Petrovski, G., Zahuczky, G., Katona, K., Vereb, G., Martinet. W., Nemes, Z., Bursch, W., Fesus, L., 2007. Clearance of dying autophagic cells of different origin by professional and non-professional phagocytes. Cell Death Diff. 14 (6),1117-1128]. Autophagy also constitutes a cell's strategy of defense upon cell damage by eliminating damaged bulk proteins/organelles. This biological condition may be exemplified by the treatment of MCF-7 cells with a necrogenic TAM-dose (10 mu M), resulting in the lysis of almost all cells within 24 h. However, a transient (1 h) challenge of MCF-7 cells with the same dose allowed the recovery of cells involving autophagy. Enrichment of chaperones in the insoluble cytoplasmic protein fraction indicated the formation of aggresomes, a potential trigger for autophagy. In a further experimental model HL60 cells were treated with TAM, causing dose-dependent distinct responses: 1-5 mu M TAM, autophagy predominant; 7-9 mu M, apoptosis predominant; 15 mu M, necrosis. These phenomena might be attributed to the degree of cell damage caused by tamoxifen, either by generating ROS, increasing membrane fluidity or forming DNA-adducts. Finally, autophagy constitutes a cell's major adaptive (survival) strategy in response to metabolic challenges such as glucose or amino acid deprivation, or starvation in general. Notably, the role of autophagy appears not to be restricted to nutrient recycling in order to maintain energy supply of cells and to adapt cell(organ) size to given physiological needs. For instance, using a newly established hepatoma cell line HCC-1.2, amino acid and glucose deprivation revealed a pro-apoptotic activity, additive to TGF-beta 1.The proapoptotic action of glucose deprivation was antagonized by 2-deoxyglucose, possibly by stabilizing the mitochondrial membrane involving the action of hexokinase II. These observations suggest that signaling cascades steering autophagy appear to provide links to those regulating cell number. Taken together, our data exemplify that a given cell may flexibly respond to type and degree of (micro)envir...

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“…11 Loss of glutamine influx may inhibit glutathione, nucleotide, and amino acid synthesis resulting in the induction of autophagy or apoptosis. 70 Normal cells may be resistant to the effects of resveratrol because the compound activates stress response networks that efficiently downregulate metabolic pathways. These networks may be lost or disabled with malignant transformation.…”

Section: Discussionmentioning

confidence: 99%

A metabolic perturbation by U0126 identifies a role for glutamine in resveratrol-induced cell death

Freeman

Kim

Lisanti

et al. 2011

Cancer Biology & Therapy

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Recent evidence has identified substantial overlap between metabolic and oncogenic biochemical pathways, suggesting novel approaches to cancer intervention. For example, cholesterol lowering statins and the antidiabetes medication metformin both act as chemopreventive agents in prostate and other cancers. The natural compound resveratrol has similar properties: increasing insulin sensitivity, suppressing adipogenesis, and inducing apoptotic death of cancer cells in vitro. However, in vivo tumor xenografts acquire resistance to resveratrol by an unknown mechanism, while mouse models of metabolic disorders respond more consistently to the compound. Here we demonstrate that castrationresistant human prostate cancer C4-2 cells are more sensitive to resveratrol-induced apoptosis than isogenic androgendependent LNCaP cells. The MEK inhibitor U0126 antagonized resveratrol-induced apoptosis in C4-2 cells, but this effect was not seen with other MEK inhibitors. U0126 was found to inhibit mitochondrial function and shift cells to aerobic glycolysis independently of MEK. Mitochondrial activity of U0126 arose through decomposition, producing both mitochondrial fluorescence and cyanide, a known inhibitor of complex IV. Applying U0126 mitochondrial inhibition to C4-2 cell apoptosis, we tested the possibility that glutamine supplementation of citric acid cycle intermediate aketoglutarate may be involved. Suppression of the conversion of glutamate to a-ketoglutarate antagonized resveratrolinduced death in C4-2 cells. A similar effect was also seen by reducing extracellular glutamine concentration in the culture medium, suggesting that resveratrol-induced death is dependent on glutamine metabolism, a process frequently dysregulated in cancer. Further work on resveratrol and metabolism in cancer is warranted to ascertain if the glutamine dependence has clinical implications.

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Nutrient deprivation induces autophagy as well as apoptosis in Chinese hamster ovary cell culture

Cited by 103 publications

References 52 publications

Acute spinal cord injury in rats should target activated autophagy

Acute spinal cord injury in rats should target activated autophagy

Cell death and autophagy: Cytokines, drugs, and nutritional factors

A metabolic perturbation by U0126 identifies a role for glutamine in resveratrol-induced cell death

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