Hippo signaling pathway in liver and pancreas: the potential drug target for tumor therapy.

Cell behaviors, including proliferation, differentiation and apoptosis, are intricately controlled during organ development and tissue regeneration. In the past 9 years, the Hippo signaling pathway has been delineated to play critical roles in organ size control, tissue regeneration and tumorigenesis through regulating cell behaviors. In mammals, the core modules of the Hippo signaling pathway include the MST1/2-LATS1/2 kinase cascade and the transcriptional co-activators YAP/TAZ.

[Regulation of differentiation of mesenchymal stem cells by the Hippo pathway effectors TAZ/YAP].

Mesenchymal stem cells (MSCs) are pluripotent cells which can differentiate into several distinct lineages, such as chondrocytes, adipocytes and myofibers. It has been reported that the lineage-specific transcriptional factors including Runt related transcription factor 2 (RUNX2), Peroxisome proliferator-activator receptor gamma (PPARgamma) and Myogenic differentiation 1 (MyoD) may play key regulatory roles among the differentiation of MSCs. Recently, researches have confirmed that the Hippo pathway impacts the differentiation fates of MSCs through regulating the activity of line- age-specific transcription factors by the Hippo pathway effectors Tafazzin (TAZ) and/or Yes-associated protein (YAP).

miR-375 inhibits proliferation of mouse pancreatic progenitor cells by targeting YAP1.

Background/aims: The Hippo signaling pathway regulates expansion and differentiation of stem cells and tissue progenitor cells during organ development and tissue regeneration. Previous studies have shown that YAP1, a potent effector of the Hippo signaling pathway, plays a crucial role in pancreas development, but the function of YAP1 in pancreatic progenitor cells is less known.

Methods: The spatio-temporal expression pattern of YAP1 in mouse developing pancreata was detected by in situ hybridization.