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Peroxiredoxin-1 protects estrogen receptor [alpha] from oxidative stress-induced suppression and is a protein biomarker of favorable prognosis in breast cancer

Introduction Peroxiredoxin-1 (PRDX1) is a multifunctional protein, acting as a hydrogen peroxide (H.sub.2O.sub.2) 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...

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Published in:Breast cancer research : BCR 2014-07, Vol.16
Main Authors: O'Leary, Patrick C, Terrile, Marta, Bajor, Malgorzata, Gaj, Pawel, Hennessy, Bryan T, Mills, Gordon B, Zagozdzon, Agnieszka, O'Connor, Darran P, Brennan, Donal J, Connor, Kate, Li, Jane, Gonzalez-Angulo, Ana Maria, Sun, Han-Dong, Pu, Jian-Xin, Pontñn, Fredrik, Uhlñn, Mathias, Jirström, Karin, Nowis, Dominika A, Crown, John P, Zagozdzon, Radoslaw, Gallagher, William M
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Language:English
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Summary:Introduction Peroxiredoxin-1 (PRDX1) is a multifunctional protein, acting as a hydrogen peroxide (H.sub.2O.sub.2) 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 H.sub.2O.sub.2, 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 ER[alpha] protein was upregulated in PRDX1 high tumors. Exogenous H.sub.2O.sub.2 treatment decreased ER[alpha] protein levels in ER-positive cells. PRDX1 knockdown further sensitized cells to H.sub.2O.sub.2- and peroxynitrite-mediated effects, whilst PRDX1 overexpression protected against this response. Inhibition of PRDX1/2 antioxidant activity with adenanthin dramatically reduced ER[alpha] 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 ER[alpha] 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.
ISSN:1465-5411
DOI:10.1186/bcr3691