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Updated: Mar 20, 2026
Detecting the Ligand-binding Domain Dimerization Activity of Estrogen Receptor Alpha Using the Mammalian Two-Hybrid Assay
Published on: December 19, 2018
Dicer expression in estrogen receptor-positive versus triple-negative breast cancer: an antibody comparison
Nicole S Spoelstra1, Diana M Cittelly1, Jessica L Christenson1
1Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045.
Abstract:
Dicer is an RNase III enzyme responsible for cleaving double-stranded RNAs into small interfering RNAs and microRNAs, which either target messenger RNA transcripts for degradation or inhibit translation. Dicer protein levels have been examined in breast cancer with contradictory results. Our goal was to resolve whether Dicer levels differ in breast cancer versus normal breast epithelium and between estrogen receptor-α-positive (ER+) or estrogen receptor-α-negative (ER-) primary breast cancers. We compared 3 different Dicer antibodies: Abcam 4A6, Abcam ab5818, and Sigma HPA000694, using immunohistochemistry and Western blot analyses. All 3 Dicer antibodies detected higher levels of Dicer in ER+ breast cancer cell lines versus ER-, and all 3 recognized exogenous overexpressed Dicer. In clinical specimens, all 3 antibodies detected higher Dicer in ER+ breast cancers versus triple-negative breast cancer (TNBC) but had very different staining patterns by immunohistochemistry on the same tumor samples. Using the optimal antibody, ab5818, selected for its sensitivity and specificity, Dicer protein expression was significantly higher in ER+ versus TNBC clinical specimens of primary tumor (P<.0001, unpaired t test). Dicer was also significantly higher in adjacent normal breast epithelium versus TNBC (P<.0001, paired t test; n=18 pairs). Differences in antibody performance may explain contrasting results observed in the literature regarding Dicer protein in breast cancer. If Dicer becomes more clinically relevant as a prognostic indicator, further antibody optimization and standardization will be critical.
Insights
Dicer protein levels are higher in estrogen receptor-positive (ER+) breast cancers compared to triple-negative breast cancer (TNBC). Antibody choice significantly impacts Dicer detection in breast cancer research.
Area of Science:
- Molecular Biology
- Oncology
- Biochemistry
Background:
- Dicer, an RNase III enzyme, processes double-stranded RNAs into small RNAs regulating gene expression.
- Previous studies show conflicting Dicer protein levels in breast cancer.
- Estrogen receptor status (ER+ vs. ER-) is a key factor in breast cancer classification.
Purpose of the Study:
- To determine if Dicer protein levels differ between breast cancer and normal breast tissue.
- To investigate Dicer levels in estrogen receptor-positive (ER+) versus estrogen receptor-α-negative (ER-) primary breast cancers.
- To evaluate and compare the performance of three different Dicer antibodies.
Main Methods:
- Immunohistochemistry and Western blot analyses were used to compare Dicer protein expression.
- Three distinct Dicer antibodies (Abcam 4A6, Abcam ab5818, Sigma HPA000694) were evaluated.
- Dicer expression was assessed in breast cancer cell lines and clinical specimens, including adjacent normal tissue.
Main Results:
- All three antibodies detected higher Dicer levels in ER+ cell lines versus ER- cell lines.
- Significant differences in Dicer protein expression were observed between ER+ and triple-negative breast cancer (TNBC) clinical specimens.
- Dicer protein expression was significantly higher in ER+ primary tumors and adjacent normal breast epithelium compared to TNBC.
Conclusions:
- Antibody variability can explain discrepancies in published Dicer protein levels in breast cancer.
- Dicer protein expression is significantly elevated in ER+ breast cancer and adjacent normal tissue compared to TNBC.
- Standardization and optimization of Dicer antibodies are crucial for its potential clinical utility as a prognostic marker.
