Quantification of PRL/Stat5 signaling with a novel pGL4-CISH reporter.
BACKGROUND
Elevations of serum prolactin (PRL) are associated with an increased risk for breast cancer. PRL signaling through its prolactin receptor (PRLr) involves the Jak2/Stat5 pathway. Luciferase-based reporter assays have been widely used to evaluate the activity of this pathway. However, the existing reporters are often not sensitive enough to monitor the effect of PRL in this pathway.


RESULTS
In this study, a new biologically relevant reporter, pGL4-CISH, was generated to study the PRL/Jak2/Stat5 signaling pathway. The sensitivity of pGL4-CISH to detect PRL was superior to that of several other commonly utilized Stat5-responsive reporters. Interestingly, the enhanced function pGL4-CISH was restricted to the estrogen receptor positive (ER+) human breast cancer cell lines T47D and MCF7, but not in the ER-MDA-231, BT-474, or MCF10A cell lines. Overexpression of Stat5 further enhanced the effect of PRL on pGL4-CISH.


CONCLUSIONS
These studies demonstrate that pGL4-CISH is a novel and sensitive reporter for assessing the activity of the PRL/Stat5 signaling pathway in the ER+ human breast cancer cells.
Fang
Feng
F
Department of Pathology, Northwestern University, Chicago, Illinois 60611 USA. f-fang@northwestern.edu
Antico
Giovanni
G
Zheng
Jiamao
J
Clevenger
Charles V
CV
D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D020869:Gene Expression Profiling / Q000379:methods*; D017930:Genes, Reporter / Q000235:genetics; D006801:Humans; D011388:Prolactin / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D050799:STAT5 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction; D050826:Suppressor of Cytokine Signaling Proteins / Q000235:genetics / Q000378:metabolism*
D011388:Prolactin; D011960:Receptors, Estrogen; D011993:Recombinant Fusion Proteins; D050799:STAT5 Transcription Factor; D050826:Suppressor of Cytokine Signaling Proteins