Transcriptional profiling identifies TNS4 function in epithelial tubulogenesis

Hepatocyte growth factor (HGF) plays central roles in tubulogenesis and metastasis [1-4]. HGF treatment of Madin-Darby canine kidney (MDCK) cells grown as cysts in three-dimensional culture induces tubulogenesis [5, 6], which like most tubulogenic processes proceeds through distinct intermediate phases. Identification of genes associated with these phases is central to understanding the molecular mechanisms of tubulogensis; however, because of inefficient, asynchronous tubule formation, isolating such genes has been unfeasible. Here we developed a synchronous, efficient tubulogenesis system and used time-course transcriptional profiling to identify genes temporally regulated in developmental intermediates. Knockdown (KD) of tensin 4 (TNS4), a particularly highly upregulated gene, leads to a decrease in formation of extensions and tubules, two sequential intermediates in tubulogenesis. Exogenous expression of TNS4 marks invasive cells in an epithelial sheet. A mutation in the SH2 domain of TNS4 prevents the transition from extension formation to invasive migration during tubule formation and leads to increased basal activation of STAT3. Exogenous expression of a constitutively active STAT3 mimics the defect by the mutation. Our study highlights the role of the TNS4-STAT3 axis in epithelial sheet invasion and tubulogenesis.