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The estrogen-related receptor α inverse agonist XCT 790 is a nanomolar mitochondrial uncoupler.

Eskiocak B, Ali A, White MA - Biochemistry (2014)

Bottom Line: Consistent with this, XCT 790 decreased mitochondrial membrane potential without affecting mitochondrial mass.Therefore, XCT 790 is a potent, fast-acting, mitochondrial uncoupler independent of its inhibition of ERRα.The biological activity together with structural features in common with the chemical uncouplers FCCP and CCCP indicates likely mode of action as a proton ionophore.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, University of Texas Southwestern Medical Center , Dallas, Texas 75390, United States.

ABSTRACT
XCT 790 is widely used to inhibit estrogen-related receptor α (ERRα) activity as an inverse agonist. Here, we report that XCT 790 potently activates AMP kinase (AMPK) in a dose-dependent and ERRα-independent manner, with active concentrations more than 25-fold below those typically used to perturb ERRα. AMPK activation is secondary to inhibition of energy production as XCT 790 rapidly depletes the pool of cellular ATP. A concomitant increase in oxygen consumption rates suggests uncoupling of the mitochondrial electron transport chain. Consistent with this, XCT 790 decreased mitochondrial membrane potential without affecting mitochondrial mass. Therefore, XCT 790 is a potent, fast-acting, mitochondrial uncoupler independent of its inhibition of ERRα. The biological activity together with structural features in common with the chemical uncouplers FCCP and CCCP indicates likely mode of action as a proton ionophore.

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Selective viability andsignaling perturbations by XCT 790. (A)Normalized cell viability of immortalized human colonic epithelialcells and colon cancer cell lines or (B) immortalized human melanocytesand melanoma cell lines 72 h after exposure to XCT 790 at the indicateddoses. Bars indicate means ± the standard deviation (N = 3). (C) Doubling of the populations of HEMn-LP, HEMn-LP(CDK4/hTERT), and HEMn-LP (E6/E7/hTERT) cells for the indicated times.(D and E) Whole cell lysates of MNT1 cells, exposed to XCT 790 for24 (D) or 1 h (E), were assessed for the accumulation of indicatedphosphorylated proteins.
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fig1: Selective viability andsignaling perturbations by XCT 790. (A)Normalized cell viability of immortalized human colonic epithelialcells and colon cancer cell lines or (B) immortalized human melanocytesand melanoma cell lines 72 h after exposure to XCT 790 at the indicateddoses. Bars indicate means ± the standard deviation (N = 3). (C) Doubling of the populations of HEMn-LP, HEMn-LP(CDK4/hTERT), and HEMn-LP (E6/E7/hTERT) cells for the indicated times.(D and E) Whole cell lysates of MNT1 cells, exposed to XCT 790 for24 (D) or 1 h (E), were assessed for the accumulation of indicatedphosphorylated proteins.

Mentions: Cells were lysedin 50 mM Tris (pH 6.8), 2% sodium dodecyl sulfate (SDS), and 10% glycerol.Samples were separated on SDS–polyacrylamide gels and transferredto polyvinylidene difluoride (PVDF) membranes for immunoblotting.AMP kinase (AMPK) activation was assessed by the accumulation of phosphorylatedAMPK at Thr170 and AMPK substrates: phosphorylated Raptor (S792),11 phosphorylated ULK1 (S555),12 and phosphorylated ACC (S79).13 Additionally, Raptor phosphorylation by AMPK inhibits mTOR activation,leading to decreased mTOR and p70 S6 kinase phosphorylation (Figures 1D,E and 3A).


The estrogen-related receptor α inverse agonist XCT 790 is a nanomolar mitochondrial uncoupler.

Eskiocak B, Ali A, White MA - Biochemistry (2014)

Selective viability andsignaling perturbations by XCT 790. (A)Normalized cell viability of immortalized human colonic epithelialcells and colon cancer cell lines or (B) immortalized human melanocytesand melanoma cell lines 72 h after exposure to XCT 790 at the indicateddoses. Bars indicate means ± the standard deviation (N = 3). (C) Doubling of the populations of HEMn-LP, HEMn-LP(CDK4/hTERT), and HEMn-LP (E6/E7/hTERT) cells for the indicated times.(D and E) Whole cell lysates of MNT1 cells, exposed to XCT 790 for24 (D) or 1 h (E), were assessed for the accumulation of indicatedphosphorylated proteins.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4116149&req=5

fig1: Selective viability andsignaling perturbations by XCT 790. (A)Normalized cell viability of immortalized human colonic epithelialcells and colon cancer cell lines or (B) immortalized human melanocytesand melanoma cell lines 72 h after exposure to XCT 790 at the indicateddoses. Bars indicate means ± the standard deviation (N = 3). (C) Doubling of the populations of HEMn-LP, HEMn-LP(CDK4/hTERT), and HEMn-LP (E6/E7/hTERT) cells for the indicated times.(D and E) Whole cell lysates of MNT1 cells, exposed to XCT 790 for24 (D) or 1 h (E), were assessed for the accumulation of indicatedphosphorylated proteins.
Mentions: Cells were lysedin 50 mM Tris (pH 6.8), 2% sodium dodecyl sulfate (SDS), and 10% glycerol.Samples were separated on SDS–polyacrylamide gels and transferredto polyvinylidene difluoride (PVDF) membranes for immunoblotting.AMP kinase (AMPK) activation was assessed by the accumulation of phosphorylatedAMPK at Thr170 and AMPK substrates: phosphorylated Raptor (S792),11 phosphorylated ULK1 (S555),12 and phosphorylated ACC (S79).13 Additionally, Raptor phosphorylation by AMPK inhibits mTOR activation,leading to decreased mTOR and p70 S6 kinase phosphorylation (Figures 1D,E and 3A).

Bottom Line: Consistent with this, XCT 790 decreased mitochondrial membrane potential without affecting mitochondrial mass.Therefore, XCT 790 is a potent, fast-acting, mitochondrial uncoupler independent of its inhibition of ERRα.The biological activity together with structural features in common with the chemical uncouplers FCCP and CCCP indicates likely mode of action as a proton ionophore.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, University of Texas Southwestern Medical Center , Dallas, Texas 75390, United States.

ABSTRACT
XCT 790 is widely used to inhibit estrogen-related receptor α (ERRα) activity as an inverse agonist. Here, we report that XCT 790 potently activates AMP kinase (AMPK) in a dose-dependent and ERRα-independent manner, with active concentrations more than 25-fold below those typically used to perturb ERRα. AMPK activation is secondary to inhibition of energy production as XCT 790 rapidly depletes the pool of cellular ATP. A concomitant increase in oxygen consumption rates suggests uncoupling of the mitochondrial electron transport chain. Consistent with this, XCT 790 decreased mitochondrial membrane potential without affecting mitochondrial mass. Therefore, XCT 790 is a potent, fast-acting, mitochondrial uncoupler independent of its inhibition of ERRα. The biological activity together with structural features in common with the chemical uncouplers FCCP and CCCP indicates likely mode of action as a proton ionophore.

Show MeSH
Related in: MedlinePlus