AP1-Luc/EF1α-mCherry Reporter Cell Line - PANC-1

AP-1 is a dimeric transcription factor composed of proteins from the Jun, Fos, ATF, and MAF families, capable of binding to TRE elements within the promoters of target genes. It serves as a convergence point for the RAS-MAPK, JNK, and PKC signaling cascades. Upon induction by growth factors, phorbol esters, or inflammatory cytokines, AP-1 activates a suite of genes—such as MMP1, MMP9, VEGFA, IL8, and CCND1—that drive cell proliferation, matrix remodeling, and invasion. The AP1-Luc/EF1α-mCherry reporter cell line is derived from PANC-1, a human pancreatic ductal adenocarcinoma cell line established from the pancreatic duct of a 56-year-old male, which harbors KRAS G12D and TP53 R273H mutations. In this reporter line, multiple AP-1 response elements drive the expression of the firefly luciferase gene, while an EF1α promoter drives the constitutive expression of an mCherry marker and a puromycin resistance gene. The resulting red fluorescent signal allows for the monitoring of cell number, independent of signaling pathway activity.

Because the oncogenic KRAS mutation keeps the AP-1 signaling pathway—specifically the MEK-ERK branch—constitutively active in this cellular context, this cell line is primarily used to measure AP-1 activity levels in pancreatic cancer cells and to screen for drugs targeting this signaling cascade. A typical experimental workflow involves stimulating the cells with agents such as EGF, TGF-α, PMA, TNF-α, or serum, followed by testing inhibitors of MEK or JNK, or compounds targeting KRAS and ERK, to assess their ability to reduce the fluorescent signal. It is well-established that in PANC-1 cells, TGF-α-induced AP-1 activation is dependent on MEK-1 and Ras. This reporter cell line can also be used to study the functions of FOSL1 and c-Jun, as well as to screen for natural products with anti-invasive activity. By utilizing the mCherry channel as an internal reference, the cell line is well-suited for experiments in 96-well or 384-well plates, eliminating the need for transient transfection across different drug dosages or during cell passage.