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Updated: Aug 8, 2026
Profiling of Estrogen-regulated MicroRNAs in Breast Cancer Cells
Published on: February 21, 2014
Cloning of estrogen-regulated messenger RNA sequences from human breast cancer cells
Abstract:
A complementary DNA library was constructed from RNA of estrogen-stimulated MCF-7 cells and screened for estrogen-regulated sequences. Four different messenger RNA sequences of varying abundance were isolated. Two of the sequences (pNR-3 and pNR-4) were induced approximately 2-fold, while the other two (pNR-1 and pNR-2) were induced at least 8-fold. The induction of both pNR-1 and pNR-2 requires similar physiological concentrations of estradiol and is near maximal at 10(-10) M. An increase in the levels of the RNAs is seen after 30 min of estrogen treatment, but pNR-1 reaches its maximal concentration faster than pNR-2. pNR-1 and pNR-2 were not expressed in all human breast cancer cell lines tested. pNR-1 was expressed and regulated by estrogen in the estrogen receptor-positive cell lines, MCF-7, T-47D, and ZR 75, whereas pNR-2 was not expressed in the T-47D cell line. pNR-1 and pNR-2 were not detected in two estrogen receptor-negative cell lines (BT20 and HBL 100). As the proliferation of the MCF-7, T47D, and ZR 75 cell lines is stimulated by estradiol, pNR-1 may provide a useful marker of hormone-responsive breast cancer.
Insights
Researchers identified two key estrogen-regulated RNA sequences, pNR-1 and pNR-2, in breast cancer cells. pNR-1 shows promise as a marker for hormone-responsive breast cancer due to its strong regulation by estradiol.
Area of Science:
- Molecular Biology
- Genetics
- Oncology
Background:
- Estrogen plays a crucial role in the proliferation of many breast cancers.
- Identifying estrogen-regulated genes is vital for understanding hormone-dependent cancer progression and developing targeted therapies.
Purpose of the Study:
- To identify and characterize novel estrogen-regulated messenger RNA (mRNA) sequences in human breast cancer cells.
- To evaluate the potential of these sequences as biomarkers for hormone-responsive breast cancer.
Main Methods:
- Construction of a complementary DNA (cDNA) library from estrogen-stimulated MCF-7 cells.
- Screening the library for estrogen-regulated sequences using hybridization techniques.
- Quantification of mRNA levels and assessment of expression patterns in various human breast cancer cell lines.
Main Results:
- Four estrogen-regulated mRNA sequences (pNR-1, pNR-2, pNR-3, pNR-4) were isolated.
- pNR-1 and pNR-2 exhibited significant induction (at least 8-fold) by estradiol at physiological concentrations (near maximal at 10(-10) M).
- pNR-1 and pNR-2 showed differential expression across breast cancer cell lines; pNR-1 was regulated by estrogen in estrogen receptor-positive lines (MCF-7, T-47D, ZR 75), while pNR-2 was not expressed in T-47D cells and neither were detected in estrogen receptor-negative lines (BT20, HBL 100).
Conclusions:
- pNR-1 and pNR-2 are novel estrogen-regulated genes in breast cancer cells.
- pNR-1 demonstrates specific expression and regulation in hormone-responsive breast cancer cell lines, suggesting its potential as a biomarker for predicting response to endocrine therapy.
