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ERβ1: characterization, prognosis, and evaluation of treatment strategies in ERα-positive and -negative breast cancer.

Reese JM, Suman VJ, Subramaniam M, Wu X, Negron V, Gingery A, Pitel KS, Shah SS, Cunliffe HE, McCullough AE, Pockaj BA, Couch FJ, Olson JE, Reynolds C, Lingle WL, Spelsberg TC, Goetz MP, Ingle JN, Hawse JR - BMC Cancer (2014)

Bottom Line: The role and clinical value of ERβ1 expression is controversial and recent data demonstrates that many ERβ antibodies are insensitive and/or non-specific.However, in the absence of ERα expression, ERβ-specific agonists potently inhibited cell proliferation rates while anti-estrogenic therapies were ineffective.However, the efficacy of SERMs and ERβ-specific agonists differ as a function of ERα expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Mayo Clinic, 16-01B Guggenheim Building, 200 First St, SW, Rochester, MN 55905, USA. hawse.john@mayo.edu.

ABSTRACT

Background: The role and clinical value of ERβ1 expression is controversial and recent data demonstrates that many ERβ antibodies are insensitive and/or non-specific. Therefore, we sought to comprehensively characterize ERβ1 expression across all sub-types of breast cancer using a validated antibody and determine the roles of this receptor in mediating response to multiple forms of endocrine therapy both in the presence and absence of ERα expression.

Methods: Nuclear and cytoplasmic expression patterns of ERβ1 were analyzed in three patient cohorts, including a retrospective analysis of a prospective adjuvant tamoxifen study and a triple negative breast cancer cohort. To investigate the utility of therapeutically targeting ERβ1, we generated multiple ERβ1 expressing cell model systems and determined their proliferative responses following anti-estrogenic or ERβ-specific agonist exposure.

Results: Nuclear ERβ1 was shown to be expressed across all major sub-types of breast cancer, including 25% of triple negative breast cancers and 33% of ER-positive tumors, and was associated with significantly improved outcomes in ERα-positive tamoxifen-treated patients. In agreement with these observations, ERβ1 expression sensitized ERα-positive breast cancer cells to the anti-cancer effects of selective estrogen receptor modulators (SERMs). However, in the absence of ERα expression, ERβ-specific agonists potently inhibited cell proliferation rates while anti-estrogenic therapies were ineffective.

Conclusions: Using a validated antibody, we have confirmed that nuclear ERβ1 expression is commonly present in breast cancer and is prognostic in tamoxifen-treated patients. Using multiple breast cancer cell lines, ERβ appears to be a novel therapeutic target. However, the efficacy of SERMs and ERβ-specific agonists differ as a function of ERα expression.

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Related in: MedlinePlus

Effects of anti-estrogenic (A) and ERβ agonist (B) treatment on the proliferation rates of MDA-MB-231-ERβ1 and Hs578t-ERβ1 cells. Crystal violet assays were used to determine proliferation rates following indicated treatments for 12 days. P-values < 0.05 were considered to be statistically significant. *Denotes significant difference between indicated treatment and vehicle control treated cells and # between indicated treatment and estrogen treated cells.
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Fig5: Effects of anti-estrogenic (A) and ERβ agonist (B) treatment on the proliferation rates of MDA-MB-231-ERβ1 and Hs578t-ERβ1 cells. Crystal violet assays were used to determine proliferation rates following indicated treatments for 12 days. P-values < 0.05 were considered to be statistically significant. *Denotes significant difference between indicated treatment and vehicle control treated cells and # between indicated treatment and estrogen treated cells.

Mentions: We next performed a series of proliferation assays to determine which therapeutic strategies may be most effective for the treatment of ERβ1 positive TNBC. Interestingly, estrogen treatment (1 nM) was shown to substantially inhibit the proliferation rates of MDA-MB-231-ERβ1 cells (Figure 5), an effect that was not observed in the absence of doxycycline (data not shown). The addition of multiple anti-estrogens significantly reversed the inhibitory effect of estrogen in MDA-MB-231-ERβ1 cells (Figure 5A). In order to ensure that these effects were not unique to the MD-MB-231 cell line, identical assays were performed using Hs578T-ERβ1 expressing cells [8]. Estrogen treatment significantly repressed proliferation of Hs578T-ERβ1 cells, effects that were reversed following the addition of endoxifen, 4HT or ICI (Figure 5A). Similar responses were observed in the MDA-MB-231-ERβ1 clonal cell line #12 (Additional file 3: Figure S3A).Figure 5


ERβ1: characterization, prognosis, and evaluation of treatment strategies in ERα-positive and -negative breast cancer.

Reese JM, Suman VJ, Subramaniam M, Wu X, Negron V, Gingery A, Pitel KS, Shah SS, Cunliffe HE, McCullough AE, Pockaj BA, Couch FJ, Olson JE, Reynolds C, Lingle WL, Spelsberg TC, Goetz MP, Ingle JN, Hawse JR - BMC Cancer (2014)

Effects of anti-estrogenic (A) and ERβ agonist (B) treatment on the proliferation rates of MDA-MB-231-ERβ1 and Hs578t-ERβ1 cells. Crystal violet assays were used to determine proliferation rates following indicated treatments for 12 days. P-values < 0.05 were considered to be statistically significant. *Denotes significant difference between indicated treatment and vehicle control treated cells and # between indicated treatment and estrogen treated cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4196114&req=5

Fig5: Effects of anti-estrogenic (A) and ERβ agonist (B) treatment on the proliferation rates of MDA-MB-231-ERβ1 and Hs578t-ERβ1 cells. Crystal violet assays were used to determine proliferation rates following indicated treatments for 12 days. P-values < 0.05 were considered to be statistically significant. *Denotes significant difference between indicated treatment and vehicle control treated cells and # between indicated treatment and estrogen treated cells.
Mentions: We next performed a series of proliferation assays to determine which therapeutic strategies may be most effective for the treatment of ERβ1 positive TNBC. Interestingly, estrogen treatment (1 nM) was shown to substantially inhibit the proliferation rates of MDA-MB-231-ERβ1 cells (Figure 5), an effect that was not observed in the absence of doxycycline (data not shown). The addition of multiple anti-estrogens significantly reversed the inhibitory effect of estrogen in MDA-MB-231-ERβ1 cells (Figure 5A). In order to ensure that these effects were not unique to the MD-MB-231 cell line, identical assays were performed using Hs578T-ERβ1 expressing cells [8]. Estrogen treatment significantly repressed proliferation of Hs578T-ERβ1 cells, effects that were reversed following the addition of endoxifen, 4HT or ICI (Figure 5A). Similar responses were observed in the MDA-MB-231-ERβ1 clonal cell line #12 (Additional file 3: Figure S3A).Figure 5

Bottom Line: The role and clinical value of ERβ1 expression is controversial and recent data demonstrates that many ERβ antibodies are insensitive and/or non-specific.However, in the absence of ERα expression, ERβ-specific agonists potently inhibited cell proliferation rates while anti-estrogenic therapies were ineffective.However, the efficacy of SERMs and ERβ-specific agonists differ as a function of ERα expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Mayo Clinic, 16-01B Guggenheim Building, 200 First St, SW, Rochester, MN 55905, USA. hawse.john@mayo.edu.

ABSTRACT

Background: The role and clinical value of ERβ1 expression is controversial and recent data demonstrates that many ERβ antibodies are insensitive and/or non-specific. Therefore, we sought to comprehensively characterize ERβ1 expression across all sub-types of breast cancer using a validated antibody and determine the roles of this receptor in mediating response to multiple forms of endocrine therapy both in the presence and absence of ERα expression.

Methods: Nuclear and cytoplasmic expression patterns of ERβ1 were analyzed in three patient cohorts, including a retrospective analysis of a prospective adjuvant tamoxifen study and a triple negative breast cancer cohort. To investigate the utility of therapeutically targeting ERβ1, we generated multiple ERβ1 expressing cell model systems and determined their proliferative responses following anti-estrogenic or ERβ-specific agonist exposure.

Results: Nuclear ERβ1 was shown to be expressed across all major sub-types of breast cancer, including 25% of triple negative breast cancers and 33% of ER-positive tumors, and was associated with significantly improved outcomes in ERα-positive tamoxifen-treated patients. In agreement with these observations, ERβ1 expression sensitized ERα-positive breast cancer cells to the anti-cancer effects of selective estrogen receptor modulators (SERMs). However, in the absence of ERα expression, ERβ-specific agonists potently inhibited cell proliferation rates while anti-estrogenic therapies were ineffective.

Conclusions: Using a validated antibody, we have confirmed that nuclear ERβ1 expression is commonly present in breast cancer and is prognostic in tamoxifen-treated patients. Using multiple breast cancer cell lines, ERβ appears to be a novel therapeutic target. However, the efficacy of SERMs and ERβ-specific agonists differ as a function of ERα expression.

Show MeSH
Related in: MedlinePlus