Fig. 2

Schematic of the mechanism of miR-34 in EMT. There are two feedback loops. One is the miR-34a-p53 loop, they reinforce each other to regulate EMT. Another loop consists of miR-34a, IL-6R and STAT3, the decrease of miR-34a in cancer can induce the expression of IL-6R which increases the activity of STAT3, meanwhile STAT3 further represses miR-34a expression. Among this process, IL-6R is essential for EMT. Interestingly, p53 connects this two important loops. In addition, miR-34a regulates EMT via some vital EMT-EFs, such as SNAIL, ZEB and SLUG. Furthermore, some EMT-associated signal pathways are also the agencies between miR-34a and EMT. For example, miR-34a inhibits the expression of NOTCH and JAG1 to regulate the NOTCH pathway, the WNT pathway also is represses by miR-34a via decreasing the expression of β-catenin, LEF1 and WNT, miR-34a also can reduces the activity of TGF-β/SMAD pathway by suppressing the expression of TGF-βR1, SMAD4 and p-SMAD3. Through these essential signal pathways, miR-34a achieves the modulation of EMT