EMT or MET, This is the question
The process of Epithelial-Mesenchymal Transition(EMT) and its reverse process, Mesenchymal-Epithelial Transition(MET), have been under intense research during last decade. Various results suggest their implication in development, disease and cancer metastasis. However new studies point to yet another properties of these processes.
Mani et al. in their elegant study, which was published in Cell journal, demonstrated that cancer cells that have undergone EMT show stem cell properties. These results imply that epithelial cells that lose epithelial characteristic, as a direct consequence of EMT program, are more amenable to become stem cells or stem-like cells.
But in papers from Li et al and Samavarchi-Tehrani et al published recently in Cell Stem Cell journal, they cleverly demonstrated that the first and the limiting step in the process of induced pluripotent stem cell (iPSC) formation from fibroblasts is set of events that closely resembles that of MET. In fact the authors thoughtfully predict that epithelial cells are more amenable to become stem cells in comparison to mesenchymal fibroblasts cells.
This contradiction may stem from the fact, that these two study are very different in context and nature. However it would be very interesting to understand the molecular mechanism of each context conducive to stem cell traits.