Fig. 4.
TGF-β activated several transcription factors to modulate EMT: upon activation of the TGF-β signaling via Smad or non-Smad pathways (MAPK, RhoA and PI3P), several transcription factors such as basic helix-loop-helix factors (bHLH) as well zinc finger factors can be activated. E-cadherin is commonly repressed by these transcription factors (as shown by round and oval structures bound onto the DNA in the nucleus) by promoting E-cadherin gene silencing, thus activating EMT. These transcription factors can be activated by several external stimulations other than TGF-β, such as Wnt, integrin, stress, BMPs and activins, interferons and number of growth factors [such as epidermal growth factors (EFG), HGF, PDGF and IGF]. It is quite intriguing.