Development of a Novel ECAD-EmGFP Reporter Line for Pancreatic Cancer MET Study and Drug Discovery

World-wide, metastasis continues to be the leading cause of death in cancer patients. Although epithelial-to-mesenchymal transition (EMT) and mesenchymal-to-epithelial transition (MET) have been implicated in the progression of cancer metastasis and drug resistance, their mechanistic pathway and specific role in disease progression is not fully understood. As such, the development of a reporter line that enables the real-time monitoring of the changing status of cells will not only aid in dissecting the EMT/MET pathway in the research field, but could also become a robust platform for new cancer drug development.

E-cadherin, an adhesion protein expressed in epithelial cells, is upregulated in pancreatic cancer cells during MET and is associated with an increase in tight junctions and apico-basal polarity, as well as a change in morphology. Here, we developed a novel PANC-1 ECAD-EmGFP reporter line using CRISPR/Cas9 genome-editing technology. In this cell line, the emerald green fluorescent protein (EmGFP) reporter was incorporated into the last exon of the endogenous E-cadherin gene, enabling real-time monitoring of MET status in live cells. The ECAD-EmGFP knock-in allele was confirmed at genomic, transcriptional, and translational levels. Functional data revealed that miRNA-200 treatment induced the increased expression of ECAD-EmGFP, and decreased expression of Snail, a transcription factor associated with mesenchymal traits. These changes in marker gene expression, as well as the decrease in invasive capacity upon induction, suggest that cells have undergone MET. This cell line is a valuable tool for dissecting the molecular mechanisms underlying EMT and MET and for evaluating or screening compounds targeting EMT and MET in pancreatic cancer.