STAT3 Responsive Luciferase Reporter HepG2 Stable Cell Line is derived from human liver cancer, and stably express firefly luciferase reporter gene under the control of the STAT3 response element.  This cell line is an ideal cellular model for monitoring the activation of JAK-STAT receptor signaling pathway triggered by stimuli treatment, enforced gene expression and gene knockdown.
 
STAT3 is activated in response to various cytokines and growth factors including IL-6 and OSM. The activation of STAT3 results in formation of STAT3 homodimers and STAT3/STAT1 heterodimers that translocate to the cell nucleus and induce transcription of genes by binding to the consensus element on the promoter region of target genes associated with cell growth and apoptosis. Signosis has established and launched the STAT3 Luciferase Reporter HepG2 Stable Cell Line, which can be used as a reporter system for monitoring the activation of Stat3 triggered by stimuli treatment, enforced gene expression and gene knockdown.
 
The cell line was established by transfection using a pTA-Stat3-luciferase reporter vector, which contains 4 repeats of Stat3 binding sites, a minimal promoter upstream of the firefly luciferase coding region, along with hygromycin expression vector followed by hygromycin selection. The hygromycin resistant clones were subsequently screened for oncostatin induced luciferase activity. The clone with the highest fold induction (10 fold) was selected and expanded to produce this stable cell line.
 
Principle behind TF luciferase reporter. TF luciferase reporter stable cell line utilizes artificial promoter constructs to drive luciferase expression. The promoter region can consists of multiple repeats of a cis-element TF binding site, a DNA fragment from the promoter region of a known TF downstream gene, or a DNA fragment containing putative/known TF binding sites. There are several ways that a TF can be activated, such as through extracellular stimuli or through intracellular signaling pathways. Once activated, the TF translocates to the nucleus and often interacts with relevant co-factors to drive gene expression. Once luciferase is expressed, it can generate light in an enzymatic assay and the amount of light measured is positively correlated with the level of TF activation.