Signalling pathways in the induction of proteasome expression by proteolysis-inducing factor in murine myotubes

Wyke, Stacey M.; Khal, Jwan; Tisdale, Michael J.

doi:10.1016/j.cellsig.2004.05.015

Cited by 22 publications

(20 citation statements)

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“…Activation of protein kinase C (PKC) is also important in activation of NADPH oxidase and has been shown to be essential in the PIF-induced expression of the ubiquitin-proteasome pathway, through activation of NFB (243). Activation of PKC could arise directly from AA, but most likely involves conversion of AA by 15-lipoxygenase (15-LOX) to 15-hydroxyeicosatetraenoic acid (15-HETE), since inhibitors of 15-LOX have been shown to attenuate muscle atrophy in a murine cachexia model (288). AA has been shown to induce direct interaction between the NADPH oxidase subunits p47 phox and p22 phox , while phosphorylation of p47 phox by PKC partly replaces the effect of AA (211).…”

Section: Apoptosis In Skeletal Musclementioning

confidence: 99%

Mechanisms of Cancer Cachexia

Tisdale

2009

Physiological Reviews

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Up to 50% of cancer patients suffer from a progressive atrophy of adipose tissue and skeletal muscle, called cachexia, resulting in weight loss, a reduced quality of life, and a shortened survival time. Anorexia often accompanies cachexia, but appears not to be responsible for the tissue loss, particularly lean body mass. An increased resting energy expenditure is seen, possibly arising from an increased thermogenesis in skeletal muscle due to an increased expression of uncoupling protein, and increased operation of the Cori cycle. Loss of adipose tissue is due to an increased lipolysis by tumor or host products. Loss of skeletal muscle in cachexia results from a depression in protein synthesis combined with an increase in protein degradation. The increase in protein degradation may include both increased activity of the ubiquitin-proteasome pathway and lysosomes. The decrease in protein synthesis is due to a reduced level of the initiation factor 4F, decreased elongation, and decreased binding of methionyl-tRNA to the 40S ribosomal subunit through increased phosphorylation of eIF2 on the α-subunit by activation of the dsRNA-dependent protein kinase, which also increases expression of the ubiquitin-proteasome pathway through activation of NFκB. Tumor factors such as proteolysis-inducing factor and host factors such as tumor necrosis factor-α, angiotensin II, and glucocorticoids can all induce muscle atrophy. Knowledge of the mechanisms of tissue destruction in cachexia should improve methods of treatment.

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Section: Apoptosis In Skeletal Musclementioning

confidence: 99%

Mechanisms of Cancer Cachexia

Tisdale

2009

Physiological Reviews

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994

1,061

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“…PKC activation is also critical for PIF-triggered activation of NF-κB, though whether it is sufficient for this activation is not clear. 128,129 It now is well known that diets high in EPA-rich fish oil can have a favorable impact on cancer cachexia, both in tumor-bearing rodents and in human patients. Tisdale has examined the impact of EPA on PIFstimulated murine myotubes in vitro.…”

Section: Preventing Cachexiamentioning

confidence: 99%

Toward a Core Nutraceutical Program for Cancer Management

McCarty

Block

2006

Integr Cancer Ther

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As previously suggested, it may be feasible to impede tumorevoked angiogenesis with a nutraceutical program composed of glycine, fish oil, epigallocatechin-3-gallate, selenium, and silymarin, complemented by a low-fat vegan diet, exercise training, and, if feasible, a salicylate and the drug tetrathiomolybdate. It is now proposed that the scope of this program be expanded to address additional common needs of cancer patients: blocking the process of metastasis; boosting the cytotoxic capacity of innate immune defenses (natural killer [NK] cells); preventing cachexia, thromboembolism, and tumor-induced osteolysis; and maintaining optimal micronutrient status. Modified citrus pectin, a galectin-3 antagonist, has impressive antimetastatic potential. Mushroom β-glucans and probiotic lactobacilli can amplify NK activity via stimulatory effects on macrophages. Selenium, β-carotene, and glutamine can also increase the number and/or cytotoxic activity of NK cells. Cachectic loss of muscle mass can be opposed by fish oil, glutamine, and β-hydroxy-β-methylbutyrate. Fish oil, policosanol, and vitamin D may have potential for control of osteolysis. High-dose aspirin or salicylates, by preventing NF-κB activation, can be expected to aid prevention of metastasis and cachexia while down-regulating osteolysis, but their impacts on innate immune defenses will not be entirely favorable. A nutritional insurance formula crafted for the special needs of cancer patients can be included in this regimen. To minimize patient inconvenience, this complex core nutraceutical program could be configured as an oil product, a powder, and a capsule product, with the nutritional insurance formula provided in tablets. It would be of interest to test this program in nude mouse xenograft models.

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“…Exogenous provision of the 5-LOX product LTB 4 enhances myoblast proliferation/ differentiation during myogenesis (48). On the other hand, the 15-LOX product 15-HETE has been implicated in mediating the skeletal muscle protein degradation response to the cata-bolic proteolysis-inducing factor (43,57,59). The collective role of the diverse and opposing effects of individual eicosanoids on muscle cell biology in physiological states of skeletal muscle hypertrophy and atrophy remains unclear.…”

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Arachidonic acid supplementation enhances in vitro skeletal muscle cell growth via a COX-2-dependent pathway

Markworth

Cameron‐Smith

2013

American Journal of Physiology-Cell Physiology

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[e.g., prostaglandins (PGs), leukotrienes, and hydroxyeicosatetraenoic acids] has been implicated in skeletal muscle cell growth and development. The collective role of AA-derived metabolites in physiological states of skeletal muscle growth/atrophy remains unclear. The present study aimed to determine the direct effect of free AA supplementation and subsequent eicosanoid biosynthesis on skeletal myocyte growth in vitro. C2C12 (mouse) skeletal myocytes induced to differentiate with supplemental AA exhibited dose-dependent increases in the size, myonuclear content, and protein accretion of developing myotubes, independent of changes in cell density or the rate/extent of myogenic differentiation. Nonselective (indomethacin) or cyclooxygenase 2 (COX-2)-selective (NS-398) nonsteroidal anti-inflammatory drugs blunted basal myogenesis, an effect that was amplified in the presence of supplemental free AA substrate. The stimulatory effects of AA persisted in preexisting myotubes via a COX-2-dependent (NS-389-sensitive) pathway, specifically implying dependency on downstream PG biosynthesis. AAstimulated growth was associated with markedly increased secretion of PGF 2␣ and PGE2; however, incubation of myocytes with PG-rich conditioned medium failed to mimic the effects of direct AA supplementation. In vitro AA supplementation stimulates PG release and skeletal muscle cell hypertrophy via a COX-2-dependent pathway. arachidonic acid; C2C12; growth; nonsteroidal anti-inflammatory drug; skeletal muscle ARACHIDONIC ACID (AA) is a polyunsaturated -6 fatty acid [20:4(6)], present in the diet, that is incorporated into cell membrane phospholipids (PLs) (19). Dietary change elicits rapid alterations in PL fatty acid composition, with supplemental AA increasing plasma PL abundance within days (42). In response to cellular perturbation (e.g., mechanical trauma, cytokines, or growth factors), AA is cleaved from PL molecules via the action of the enzyme PLA 2 . Free intracellular AA serves as a key transient cell-signaling intermediate, undergoing rapid enzymatic conversion to a diverse array of inflammatory autocrine/paracrine eicosanoid lipid mediators. Parallel cyclooxygenase (COX-1/COX-2) and lipoxygenase (5-LOX/ 12-LOX/15-LOX) pathways catalyze the oxidation of AA to ultimately produce the PGs (PGD 2 , PGE 2 , PGF 2␣ , PGI 2 , and thromboxane A 2 ) and the leukotriene (LT)/lipoxin (LX) families of eicosanoids, respectively. Nonsteroidal anti-inflammatory drugs (NSAIDs) are thought to exert their anti-inflammatory, analgesic, and antipyretic action, specifically by inhibition of the COX branch of the AA pathway, indicative of a central role of PG species in mediating the inflammatory response.Skeletal muscle cells express the COX genes COX-1 and COX-2 (49) and locally synthesize/release AA-derived PGs, including PGD 2 (56), PGE 2 /PGF 2␣ (33,40,41,54), and PGI 2 (2). NSAID treatment is associated with deleterious effects on adaptive skeletal muscle growth/regeneration (3, 4, 31, 39 -41, 46), consistent with the inflammatory res...

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Signalling pathways in the induction of proteasome expression by proteolysis-inducing factor in murine myotubes

Cited by 22 publications

References 19 publications

Mechanisms of Cancer Cachexia

Mechanisms of Cancer Cachexia

Toward a Core Nutraceutical Program for Cancer Management

Arachidonic acid supplementation enhances in vitro skeletal muscle cell growth via a COX-2-dependent pathway

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