title: TGFβ-induced invasion of prostate cancer cells is promoted by c-Jun-dependent transcriptional activation of Snail1.
abstract: High levels of transforming growth factor-β (TGFβ) correlate with poor prognosis for patients with prostate cancer and other cancers. TGFβ is a multifunctional cytokine and crucial regulator of cell fate, such as epithelial to mesenchymal transition (EMT), which is implicated in cancer invasion and progression. TGFβ conveys its signals upon binding to type I and type II serine/threonine kinase receptors (TβRI/II); phosphorylation of Smad2 and Smad3 promotes their association with Smad4, which regulates expression of targets genes, such as Smad7, p21, and c-Jun. TGFβ also activates the ubiquitin ligase tumor necrosis factor receptor-associated factor 6 (TRAF6), which associates with TβRI and activates the p38 mitogen-activated protein kinase (MAPK) pathway. Snail1 is a key transcription factor, induced by TGFβ that promotes migration and invasion of cancer cells. In this study, we have identified a novel binding site for c-Jun in the promoter of the Snail1 gene and report that the activation of the TGFβ-TRAF6-p38 MAPK pathway promotes both c-Jun expression and its activation via p38α-dependent phosphorylation of c-Jun at Ser63. The TRAF6-dependent activation of p38 also leads to increased stability of c-Jun, due to p38-dependent inactivation of glycogen synthase kinase (GSK) 3β by phosphorylation at Ser9. Thus, our findings elucidate a novel role for the p38 MAPK pathway in stimulated cells, leading to activation of c-Jun and its binding to the promoter of Snail1, thereby triggering motility and invasiveness of aggressive human prostate cancer cells.
authors.affiliation: a Ludwig Institute for Cancer Research; Science for Life Laboratory; Uppsala University; Uppsala, Sweden.
authors.forename: Noopur
authors.initials: N
authors.lastname: Thakur
authors.forename: Shyam Kumar
authors.initials: SK
authors.lastname: Gudey
authors.forename: Anders
authors.initials: A
authors.lastname: Marcusson
authors.forename: Jing Yi
authors.initials: JY
authors.lastname: Fu
authors.forename: Anders
authors.initials: A
authors.lastname: Bergh
authors.forename: Carl-Henrik
authors.initials: CH
authors.lastname: Heldin
authors.forename: Marene
authors.initials: M
authors.lastname: Landström
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics / Q000473:pathology; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D008297:Male; D009361:Neoplasm Invasiveness / Q000235:genetics; D011401:Promoter Regions, Genetic; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000473:pathology*; D012694:Serine / Q000378:metabolism; D000071250:Snail Family Transcription Factors; D048029:TNF Receptor-Associated Factor 6 / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation; D016212:Transforming Growth Factor beta / Q000378:metabolism*
chemical_list: C000604407:SNAI1 protein, human; D000071250:Snail Family Transcription Factors; D048029:TNF Receptor-Associated Factor 6; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D012694:Serine; D048031:JNK Mitogen-Activated Protein Kinases
keywords: Smads; Snail1; TGFβ; TRAF6; c-Jun; invasion; p38 MAPK; prostate cancer