Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2014 Jul 10;16(4):R79.
doi: 10.1186/bcr3691.

Peroxiredoxin-1 Protects Estrogen Receptor α From Oxidative Stress-Induced Suppression and Is a Protein Biomarker of Favorable Prognosis in Breast Cancer

Free PMC article

Peroxiredoxin-1 Protects Estrogen Receptor α From Oxidative Stress-Induced Suppression and Is a Protein Biomarker of Favorable Prognosis in Breast Cancer

Patrick C O'Leary et al. Breast Cancer Res. .
Free PMC article

Abstract

Introduction: Peroxiredoxin-1 (PRDX1) is a multifunctional protein, acting as a hydrogen peroxide (H2O2) scavenger, molecular chaperone and immune modulator. Although differential PRDX1 expression has been described in many tumors, the potential role of PRDX1 in breast cancer remains highly ambiguous. Using a comprehensive antibody-based proteomics approach, we interrogated PRDX1 protein as a putative biomarker in estrogen receptor (ER)-positive breast cancer.

Methods: An anti-PRDX1 antibody was validated in breast cancer cell lines using immunoblotting, immunohistochemistry and reverse phase protein array (RPPA) technology. PRDX1 protein expression was evaluated in two independent breast cancer cohorts, represented on a screening RPPA (n = 712) and a validation tissue microarray (n = 498). In vitro assays were performed exploring the functional contribution of PRDX1, with oxidative stress conditions mimicked via treatment with H2O2, peroxynitrite, or adenanthin, a PRDX1/2 inhibitor.

Results: In ER-positive cases, high PRDX1 protein expression is a biomarker of improved prognosis across both cohorts. In the validation cohort, high PRDX1 expression was an independent predictor of improved relapse-free survival (hazard ratio (HR) = 0.62, 95% confidence interval (CI) = 0.40 to 0.96, P = 0.032), breast cancer-specific survival (HR = 0.44, 95% CI = 0.24 to 0.79, P = 0.006) and overall survival (HR = 0.61, 95% CI = 0.44 to 0.85, P = 0.004). RPPA screening of cancer signaling proteins showed that ERα protein was upregulated in PRDX1 high tumors. Exogenous H2O2 treatment decreased ERα protein levels in ER-positive cells. PRDX1 knockdown further sensitized cells to H2O2- and peroxynitrite-mediated effects, whilst PRDX1 overexpression protected against this response. Inhibition of PRDX1/2 antioxidant activity with adenanthin dramatically reduced ERα levels in breast cancer cells.

Conclusions: PRDX1 is shown to be an independent predictor of improved outcomes in ER-positive breast cancer. Through its antioxidant function, PRDX1 may prevent oxidative stress-mediated ERα loss, thereby potentially contributing to maintenance of an ER-positive phenotype in mammary tumors. These results for the first time imply a close connection between biological activity of PRDX1 and regulation of estrogen-mediated signaling in breast cancer.

Figures

Figure 1
Figure 1
Validation of the PRDX1 antibody specificity using immunoblotting, RPPA and IHC platforms. (A) Immunoblotting shows a discrete signal, the intensity of which correlates with PRDX1 knockdown/overexpression across recombinant ZR-75-1 cell lines (V5-tagged PRDX1 protein runs at 25 kDa, with native protein at 22 kDa). (B) Correlation between Western blotting densitometry and RPPA log2 expression values from recombinant ZR-75-1 cell lines protein lysates. (C) Immunoblotting, (D) cell pellet arrays (upper panels: DAB and hematoxylin staining; lower panel: DAB staining only) and (E) automated analysis scoring from recombinant SKBR3 breast cancer cell lines (automated scoring includes data from cells stained with PRDX1 antibody or PBS-T only control). (F) Representation of tissue cores and associated mark-up images after automated analysis (x40 magnification). (G) Example of PRDX1 cytoplasmic staining. (ns: non-significant; **P <0.01; ***P <0.001). IHC, immunohistochemistry; PBS-T, phosphate-buffered saline with 0.1% Tween-20; PRDX1, peroxiredoxin 1; RPPA, reverse phase protein arrays.
Figure 2
Figure 2
Prognostic value of PRDX1 protein in ER-positive breast tumors on an RPPA cohort (cohort 1). Kaplan-Meier analysis showing associations between (A) RFS, (B) BCSS and (C) OS with high/low PRDX1 expression stratified by the median. The overall and ER + cohorts are shown. Significant log-rank P values are in italic (P <0.05). BCSS, breast cancer-specific survival; ER, estrogen receptor; PRDX1, peroxiredoxin 1; OS, overall survival; RFS, recurrence-free survival; RPPA, reverse phase protein arrays.
Figure 3
Figure 3
Prognostic value of PRDX1 protein in primary ER-positive breast tumors on an independent TMA (cohort 2). Kaplan-Meier analysis showing associations between (A) RFS, (B) BCSS and (C) OS with high/low PRDX1 expression stratified by the median. The overall and ER + cohorts are shown. Significant P values are in italic (P <0.05). BCSS, breast cancer-specific survival; ER, estrogen receptor; OS, overall survival; PRDX1, peroxiredoxin 1; RFS, recurrence-free survival; TMA, tissue microarray.
Figure 4
Figure 4
PRDX1 protein expression and correlation with cancer-signaling proteins in ER-positive tumors from the TCGA RPPA cohort (cohort 3). (A) ERα protein distribution across all breast tumors as measured by RPPA. The threshold for ER-negative and -positive cases was < -1.9 and > -1.4 of the log2 transformed signal, respectively. (B) PRDX1 protein distribution across the ER-positive cohort (n = 289). (C) Differentially expressed proteins between the upper and lower quartiles of PRDX1 protein expression (quartile size: n = 72) in ER-positive tumors. ERα and Claudin-7 are upregulated while Collagen-VI, pT202/pY204-MAPK and HSP70 are downregulated in PRDX1 high tumors. These proteins are selected based on the adjusted P value <0.05 and FCabs <0.67 or >1.5. ER, estrogen receptor; PRDX1, peroxiredoxin 1; RPPA, reverse phase protein arrays; TCGA, The Cancer Genome Atlas.
Figure 5
Figure 5
Effect of PRDX1 knockdown and overexpression on the response of ERα protein expression following induction of oxidative stress in breast cancer cells. (A) PRDX1 knockdown sensitizes these ER-positive cells to H2O2-mediated ERα protein suppression while overexpression allows the cells resistance to this suppression. (B) PRDX1 knockdown sensitizes these cells to the concurrent phosphorylation of Akt at Serine-473 after treatment with increasing concentrations of H2O2, while it does not markedly alter expression of E-cadherin or phosphorylation of ERK1/2 after treatment with increasing concentrations of H2O2 for 16 hours. (C) PRDX1 knockdown sensitizes the cells to peroxynitrite-induced suppression of ERα and phosphorylation of Akt. (D) Inhibition of the antioxidant activity of PRDX1 using adenanthin suppresses ERα levels in ZR-75-1 and T47D cells, with gradual PRDX1 monomer formation. All treatments were 16 hours in duration. (Comp: complete medium only; DegPer: degraded peroxynitrite). ER, estrogen receptor; H2O2, hydrogen peroxide; PRDX1, peroxiredoxin 1.

Similar articles

See all similar articles

Cited by 22 articles

See all "Cited by" articles

References

    1. Gough DR, Cotter TG. Hydrogen peroxide: a Jekyll and Hyde signalling molecule. Cell Death Dis. 2011;2:e213. doi: 10.1038/cddis.2011.96. - DOI - PMC - PubMed
    1. Forman HJ, Maiorino M, Ursini F. Signaling functions of reactive oxygen species. Biochemistry. 2010;49:835–842. doi: 10.1021/bi9020378. - DOI - PMC - PubMed
    1. Rhee SG, Kang SW, Jeong W, Chang TS, Yang KS, Woo HA. Intracellular messenger function of hydrogen peroxide and its regulation by peroxiredoxins. Curr Opin Cell Biol. 2005;17:183–189. doi: 10.1016/j.ceb.2005.02.004. - DOI - PubMed
    1. Jang HH, Lee KO, Chi YH, Jung BG, Park SK, Park JH, Lee JR, Lee SS, Moon JC, Yun JW, Choi YO, Kim WY, Kang JS, Cheong GW, Yun DJ, Rhee SG, Cho MJ, Lee SY. Two enzymes in one; two yeast peroxiredoxins display oxidative stress-dependent switching from a peroxidase to a molecular chaperone function. Cell. 2004;117:625–635. doi: 10.1016/j.cell.2004.05.002. - DOI - PubMed
    1. Turner-Ivey B, Manevich Y, Schulte J, Kistner-Griffin E, Jezierska-Drutel A, Liu Y, Neumann CA. Role for Prdx1 as a specific sensor in redox-regulated senescence in breast cancer. Oncogene. 2013;32:5302–5314. doi: 10.1038/onc.2012.624. - DOI - PMC - PubMed

Publication types

Feedback