Stat3 inhibits WTX expression through up-regulation of microRNA-370 in Wilms tumor.

Wilms tumor (WT) is a genetically heterogeneous childhood kidney tumor. Several genetic mutations have been identified in WT patients, including inactivation of WTX, somatic stabilizing CTNNB1, and p53 mutations. However, the molecular mechanisms in tumorigenesis remain largely unexplored. Stat3 is a transcription factor that can promote oncogenesis. Stat3 activation is commonly viewed as crucial for multiple tumor proliferation and metastasis. We show that Stat3 is highly activated in Wilms tumor tissues compared to those in adjacent tissues. IL-6 treatment or transfection of a constitutively activated Stat3 in G401 cells promotes cell proliferation. At the molecular level, we further elucidate that Stat3 inhibits WTX expression through up-regulation of microRNA-370. Our results suggest that Stat3/miR-370/WTX regulatory axis might be a critical mechanism in Wilms tumor cells.