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Mol Carcinog. 2017 Oct;56(10):2290-2300. doi: 10.1002/mc.22684. Epub 2017 Jun 30.

UCP2 upregulation promotes PLCγ-1 signaling during skin cell transformation.

Author information

1
Department of Pharmacology, Toxicology and Neuroscience, LSU Health Sciences Center in Shreveport, Shreveport, Louisiana.
2
Department of Pathology, LSU Health Sciences Center in Shreveport, Shreveport, Louisiana.
3
Feist-Weiller Cancer Center, LSU Health Sciences Center in Shreveport, Shreveport, Louisiana.
4
Department of Anatomy and Cell Biology, LSU Health Sciences Center in Shreveport, Shreveport, Louisiana.

Abstract

Uncoupling protein 2 (UCP2), whose physiological role is to decrease mitochondrial membrane potential and reactive oxygen species (ROS) production, is often overexpressed in human cancers. UCP2 upregulation has recently been proposed as a novel survival mechanism for cancer cells. However, until now, how exactly UCP2 promotes tumorigenesis remains inconclusive. Based on a widely used skin cell transformation model, our data demonstrated that UCP2 differentially regulated ROS. UCP2 upregulation decreased superoxide whereas it increased hydrogen peroxide production with concomitant increase in the expression and activity of manganese superoxide dismutase (MnSOD), the primary mitochondrial antioxidant enzyme. Furthermore, hydrogen peroxide was responsible for induction of lipid peroxidation, and PLCγ-1 activation in UCP2 overexpressed cells. Additionally, PLCγ-1 activation enhanced skin cell transformation, and pharmacological, and siRNA mediated inhibition of PLCγ-1, markedly reduced colony formation, and 3D cell growth. Moreover, hydrogen peroxide scavenger, catalase, suppressed lipid peroxidation, and dampened PLCγ-1 activity. Taken together, our data suggest that (i) UCP2 is an important regulator of mitochondrial redox status and lipid signaling; (ii) hydrogen peroxide might mediate UCP2's tumor promoting activity; and (iii) pharmacological disruption of PLCγ-1 and/or hydrogen peroxide may have clinical utility for UCP2 overexpressed cancers.

KEYWORDS:

PLCγ-1; UCP2; oxidative stress; skin cell transformation

PMID:
28574619
PMCID:
PMC5582995
DOI:
10.1002/mc.22684
[Indexed for MEDLINE]
Free PMC Article

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