Prolactin/Stat5 and Androgen R1881 Coactivate Carboxypeptidase-D Gene in Breast Cancer Cells
Autor: | Samir Koirala, Catherine K.L. Too, Lynn Thomas |
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Rok vydání: | 2014 |
Předmět: |
medicine.medical_specialty
education Breast Neoplasms Interferon-gamma chemistry.chemical_compound Endocrinology Internal medicine Consensus Sequence STAT5 Transcription Factor medicine Transcriptional regulation Humans Cycloheximide Promoter Regions Genetic Molecular Biology Transcription factor STAT5 Original Research Protein Synthesis Inhibitors Regulation of gene expression Gene knockdown Base Sequence biology Metribolone Proteins General Medicine Molecular biology Prolactin Enzyme Activation Gene Expression Regulation Neoplastic Androgen receptor chemistry Receptors Androgen Enzyme Induction Androgens Dactinomycin MCF-7 Cells biology.protein STAT protein Female |
Zdroj: | Molecular Endocrinology. 28:331-343 |
ISSN: | 1944-9917 0888-8809 |
Popis: | Plasma membrane-bound carboxypeptidase-D (CPD) cleaves C-terminal arginine from extracellular substrates. In the cell, arginine is converted to nitric oxide (NO). We have reported that up-regulation of CPD mRNA/protein levels by 17β-estradiol and prolactin (PRL) in breast cancer cells, and by testosterone in prostate cancer cells, increased NO production and cell survival. The CPD promoter contains a consensus γ-interferon-activated sequence (GAS) and 3 putative androgen response elements (ARE.1, ARE.2, ARE.3) that could potentially bind PRL-activated transcription factor Stat5 (signal transducer and activator of transcription 5) and the liganded androgen receptor (AR), respectively. This study showed that synthetic androgen R1881 and PRL elevated CPD mRNA/protein levels in human MCF-7 and T47D breast cancer cells in a time-/dose-dependent manner. PRL/R1881-elevated CPD expression was blocked by actinomycin-D, and a CPD promoter construct containing these GAS and AREs was stimulated by PRL or R1881, indicating transcriptional regulation by both hormones. Luciferase reporter assays showed that GAS and the adjacent ARE.1 only were active. Mutation of GAS in the ΔGAS-CPD construct (ARE.1 intact) abolished CPD promoter activity in response to PRL and, surprisingly, to R1881 as well. ΔGAS-CPD promoter activity was restored by PRL+R1881 in combination, and enhanced by ectopic Stat5, but abolished by Stat5 gene knockdown. Chromatin immunoprecipitation analysis confirmed binding of activated Stat5 and liganded AR to GAS and ARE.1, respectively. Activated Stat5 also induced binding of unliganded AR to ARE.1, and liganded AR induced binding of unactivated Stat5 to GAS. In summary, PRL and R1881, acting through Stat5 and AR, act cooperatively to stimulate CPD gene transcription in breast cancer cells. |
Databáze: | OpenAIRE |
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