Limits...
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: 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.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

Effects of anti-estrogenic (A) and ERβ agonist (B) treatment on the proliferation rates of MCF7 and MCF7-ERβ1 expressing 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
getmorefigures.php?uid=PMC4196114&req=5

Fig3: Effects of anti-estrogenic (A) and ERβ agonist (B) treatment on the proliferation rates of MCF7 and MCF7-ERβ1 expressing 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: Based on the observation that ERβ1 expression is associated with lower rates of recurrence in ERα positive breast cancer, we sought to further characterize the effects of multiple targeted therapies using a breast cancer cell line designed to mimic this tumor sub-type. Therefore, we utilized parental and ERβ1-expressing MCF7 cells previously developed in our laboratory [12]. As a first step, we analyzed the role of ERβ1 in mediating the pro-proliferative effects of 17-beta estradiol (estrogen) and the anti-proliferative effects of anti-estrogenic compounds. As expected, estrogen treatment was shown to induce proliferation in both cell lines; however, the magnitude of induction was decreased in ERβ1 expressing cells (Figure 3A). Tamoxifen had no effect on estrogen-induced proliferation rates regardless of ERβ1 expression (Figure 3A). Interestingly, a low dose (10 nM) of 4HT increased the proliferation rate of parental MCF7 cells above that of estrogen treatment alone, an effect that was not observed in cells expressing ERβ1 (Figure 3A). Higher doses (100 nM) of endoxifen and 4HT, as well as a low dose (10 nM) of ICI, resulted in almost complete blockade of estrogen-induced proliferation in ERβ1-expressing cells but not in parental cells expressing only ERα (Figure 3A).Figure 3


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 MCF7 and MCF7-ERβ1 expressing 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

Fig3: Effects of anti-estrogenic (A) and ERβ agonist (B) treatment on the proliferation rates of MCF7 and MCF7-ERβ1 expressing 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: Based on the observation that ERβ1 expression is associated with lower rates of recurrence in ERα positive breast cancer, we sought to further characterize the effects of multiple targeted therapies using a breast cancer cell line designed to mimic this tumor sub-type. Therefore, we utilized parental and ERβ1-expressing MCF7 cells previously developed in our laboratory [12]. As a first step, we analyzed the role of ERβ1 in mediating the pro-proliferative effects of 17-beta estradiol (estrogen) and the anti-proliferative effects of anti-estrogenic compounds. As expected, estrogen treatment was shown to induce proliferation in both cell lines; however, the magnitude of induction was decreased in ERβ1 expressing cells (Figure 3A). Tamoxifen had no effect on estrogen-induced proliferation rates regardless of ERβ1 expression (Figure 3A). Interestingly, a low dose (10 nM) of 4HT increased the proliferation rate of parental MCF7 cells above that of estrogen treatment alone, an effect that was not observed in cells expressing ERβ1 (Figure 3A). Higher doses (100 nM) of endoxifen and 4HT, as well as a low dose (10 nM) of ICI, resulted in almost complete blockade of estrogen-induced proliferation in ERβ1-expressing cells but not in parental cells expressing only ERα (Figure 3A).Figure 3

Bottom Line: 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.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