Are better islet cell precursors generated by epithelial-to-mesenchymal transition?

To generate cells for replacement therapy for patients with diabetes, preclinical research is being conducted to establish in vitro systems that generate large numbers of human islets of Langerhans (or insulin-expressing beta cells). Based on the concept that undifferentiated precursor cells can expand exponentially and then be induced to differentiate into mature cells, researchers are using islet (or beta cell) precursor cells for this purpose. The cells being used include embryonic stem cells, bone marrow-derived stem cells, pancreatic stem cells and cells derived from epithelial-to-mesenchymal transition of insulin-expressing cells. Transdifferentiation of another epithelial cell type is being studied also. Herein, we review our data of epithelial-to-mesenchymal-to-epithelial transition of human insulin-expressing cells and present our hypothesis that precursor cells obtained from insulin-expressing cells by epithelial-to-mesenchymal transition, after expansion, more easily differentiate into insulin-expressing cells (by mesenchymal-to-epithelial transition) than other precursor cells or by transdifferentiation.