Adaptation of ehrlich ascites carcinoma cells to energy deprivation in vivo can be associated with heat shock protein accumulation

Kabakov, Alexander E.; Molotkov, A. O.; Budagova, Karina R.; Makarova, Yu. M.; Mosin, A.F.; Gabai, Vladimir L.

doi:10.1002/jcp.1041650102

Cited by 13 publications

(10 citation statements)

References 36 publications

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“…This heat shock model with the deletion mutant of HSP70 rather closely mimics the present situation with ATP depletion in HSP70-enriched H9c2 cells. Taking into account that HSP70 binds ADP much stronger than ATP (11,31,32) and the ATP/ADP ratio obviously declines in energy-deprived cells (15,18), it seems likely that under severe depletion of ATP in vivo, most (if not all) HSC70/HSP70 molecules are in the "ADP state." The latter is characterized as having a slower on-rate but also slower off-rate of substrate than HSP70 in the "ATP state."…”

Section: Discussionmentioning

confidence: 99%

Stressful preconditioning and HSP70 overexpression attenuate proteotoxicity of cellular ATP depletion

Kabakov

Budagova

Latchman

et al. 2002

American Journal of Physiology-Cell Physiology

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. Stressful preconditioning and HSP70 overexpression attenuate proteotoxicity of cellular ATP depletion. Am J Physiol Cell Physiol 283: C521-C534, 2002. First published March 27, 2002 10.1152/ ajpcell.00503.2001.-Rat H9c2 myoblasts were preconditioned by heat or metabolic stress followed by recovery under normal conditions. Cells were then subjected to severe ATP depletion, and stress-associated proteotoxicity was assessed on 1) the increase in a Triton X-100-insoluble component of total cellular protein and 2) the rate of inactivation and insolubilization of transfected luciferase with cytoplasmic or nuclear localization. Both heat and metabolic preconditioning elevated the intracellular heat shock protein 70 (HSP70) level and reduced cell death after sustained ATP depletion without affecting the rate and extent of ATP decrease. Each preconditioning attenuated the stress-induced insolubility among total cellular protein as well as the inactivation and insolubilization of cytoplasmic and nuclear luciferase. Transient overexpression of human HSP70 in cells also attenuated both the cytotoxic and proteotoxic effects of ATP depletion. Quercetin, a blocker of stress-responsive HSP expression, abolished the effects of stressful preconditioning but did not influence the effects of overexpressed HSP70. Analyses of the cellular fractions revealed that both the stress-preconditioned and HSP70-overexpressing cells retain the soluble pool of HSP70 longer during ATP depletion. Larger amounts of other proteins coimmunoprecipitated with excess HSP70 compared with control cells deprived of ATP. This is the first demonstration of positive correlation between chaperone activity within cells and their viability in the context of ischemia-like stress. chaperone; protein aggregation; metabolic stress; ischemic tolerance AT THE CELLULAR LEVEL, failing energy metabolism and ATP depletion are the earliest cell-damaging factors of ischemic insults. In vivo, severe depletion of ATP is a proteotoxic stress that leads to dysfunction, destabilization, and aggregation of many cellular proteins, including enzymes, ion pumps, and constituents of cytoskeletal and contractile structures (1,9,17,27). Sustained lack of ATP is obviously lethal for the cell.On the contrary, a transient (reversible) drop in cellular ATP can confer tolerance to the next energy-depriving exposure, with heat shock proteins (HSPs) being involved in such an adaptive response (reviewed in Ref. 17). The HSP-involving cellular response appears to contribute to delayed ischemic tolerance (the second window of protection) found after heat or ischemic preconditioning in the myocardium. Like high temperature, cellular ATP depletion activates the heat shock transcription factor 1 (HSF1) that afterward induces HSP expression in the recovering cells (4, 36). Most HSPs are molecular chaperones stabilizing protein molecules under heat shock conditions in vitro and in vivo, and the same chaperone activity may protect HSP-enriched cells in the case of other proteotoxic stresses, e.g....

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Section: Discussionmentioning

confidence: 99%

Stressful preconditioning and HSP70 overexpression attenuate proteotoxicity of cellular ATP depletion

Kabakov

Budagova

Latchman

et al. 2002

American Journal of Physiology-Cell Physiology

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“…Probably, tolerant cells enriched by Hsp70i can maintain the integrity of the cytoskeleton during ATP depletion [7][8][9][10] but no apparent ties between Hsp70 and microfilaments were revealed in ATP-deprived EC [2]. Nonetheless, the blocking action of quercetin indicates that the revealed effects of heat preconditioning on both Hsp27 and F-actin, and morphology of ATPdepleted EC are mediated by stress-inducible Hsp(s).…”

Section: Discussionmentioning

confidence: 99%

“…It is well known that non-lethal heat shock induces in mammalian cells the Hsp-mediated resistance to ATP depletion or ischemia, or anoxia (reviewed in [2]), though the machinery of this cross-tolerance remains to be clarified. Probably, tolerant cells enriched by Hsp70i can maintain the integrity of the cytoskeleton during ATP depletion [7][8][9][10] but no apparent ties between Hsp70 and microfilaments were revealed in ATP-deprived EC [2]. Nonetheless, the blocking action of quercetin indicates that the revealed effects of heat preconditioning on both Hsp27 and F-actin, and morphology of ATPdepleted EC are mediated by stress-inducible Hsp(s).…”

Section: Discussionmentioning

confidence: 99%

“…To prevent protein dephosphorylation under ATP depletion we used PP inhibitors sodium orthovanadate, okadaic acid and cantharidin, two latter being known to block Hsp27 dephosphorylation in vivo [20,25]. In parallel, we elevated the Hsp content in EC by heat preconditioning; herein we looked for development of the cytoskeletal tolerance to lack of ATP as it was demonstrated for other cells [7][8][9][10]. The main goal of the present work was to reveal the expected relation between the Hsp27 phosphorylation, the F-actin stability, and the level of Hsp expression in the context of ATP depletion.…”

Section: Introductionmentioning

confidence: 99%

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Protein phosphatase inhibitors and heat preconditioning prevent Hsp27 dephosphorylation, F‐actin disruption and deterioration of morphology in ATP‐depleted endothelial cells

Loktionova

Kabakov

1998

FEBS Letters

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The vascular endothelium response to ischemic depletion of ATP was studied in vitro. Endothelial cells (EC) cultured from human aorta or umbilical vein were incubated in a glucose-free medium containing CCCP or rotenone. Such blockade of energy metabolism caused a drop in ATP, destruction of actin filaments, morphological changes, and eventually disintegration of EC monolayer within 2-2.5 h. While ATP fell and F-actin collapsed, the 27-kDa heat shock protein (Hsp27) lost basal phosphorylation and became Triton X-100-insoluble forming granules inside the cell nuclei. Protein phosphatase (PP) inhibitors (okadaic acid, cantharidin, sodium orthovanadate) did not delay the ATP decrease in energydeprived EC but arrested both the alterations in the Hsp27 status and the changes for the worse in F-actin and cell morphology. Similarly, the Hsp27 dephosphorylation/insolubilization/granulation and the cytoskeletal and morphological disturbances resulting from lack of ATP were suppressed in heat-preconditioned (thermotolerant) cultures, this effect being sensitive to quercetin, a blocker of Hsp induction. The longer preservation of the cytosolic pool of phosphorylated Hsp27 during ATP depletion in the PP inhibitor-treated or thermotolerant EC correlated with the acquired resistance of F-actin and morphology. These data suggest that PP inhibitors as well as heatinducible Hsp(s) can protect ischemia-stressed cells by preventing the ATP loss-provoked protein dephosphorylation and breakdown of the actin cytoskeleton.

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“…Likewise, it is not quite understood whether the mechanisms of Hsp27-mediated cytoprotection are common under different stresses. Almost no data are available on the behaviour of the small stress proteins in ATP-depleted cells, while a possible protective role for Hsp27 during energy starvation has already been discussed [19,20].…”

Section: Introductionmentioning

confidence: 99%

Distinct effects of heat shock and ATP depletion on distribution and isoform patterns of human Hsp27 in endothelial cells

et al. 1996

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To study the cytoprotective capacity of Hsp27 under various cellular stresses, we compared the effects of heating and energy deprivation on its distribution and isoform composition. Cultured endothelial cells from human aorta or umbilical vein were subjected to heat shock (45°C) and ATP-depleting metabolic stress (CCCP or rotenone in a glucose-free medium). Both exposures led to the translocation of Hsp27 into the Triton X-100-insoluble cellular fraction, whereas the immunofluorescent Hsp27 pattern was characteristic for each stress employed. Heating (5-30 min) caused unexpected association of Hsp27 with thick bundles of actin microf'daments (stress fibers). ATP depletion within 30-120 min resulted in the appearance of Hsp27-containing compact granules in the nucleus. The insolubilization and relocallzation of Hsp27 were reversible in both cases. The stress-induced shifts in the Hsp27 isoform spectrum indicate an increase in phosphorylation of Hsp27 in heat-shocked cells and its dephosphorylation in ATP-depleted cells. We suggest that these stresses diversely affect the phosphorylation status of endothelial Hsp27, thus altering its localization, supramolecular organization and functional activity toward actin.

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Adaptation of ehrlich ascites carcinoma cells to energy deprivation in vivo can be associated with heat shock protein accumulation

Cited by 13 publications

References 36 publications

Stressful preconditioning and HSP70 overexpression attenuate proteotoxicity of cellular ATP depletion

Stressful preconditioning and HSP70 overexpression attenuate proteotoxicity of cellular ATP depletion

Protein phosphatase inhibitors and heat preconditioning prevent Hsp27 dephosphorylation, F‐actin disruption and deterioration of morphology in ATP‐depleted endothelial cells

Distinct effects of heat shock and ATP depletion on distribution and isoform patterns of human Hsp27 in endothelial cells

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