KMT2D links TGF-β signaling to noncanonical activin pathway and regulates pancreatic cancer cell plasticity
Menée à l'aide de lignées cellulaires de cancer du pancréas, de sphéroïdes, de modèles murins et d'échantillons tumoraux issus de patients, cette étude met en évidence un mécanisme par lequel le facteur TGF-bêta, en favorisant l'expression de l'activine A via la perte d'expression de la méthyltransférase KMT2D, facilite la progression tumorale et le processus métastatique
Although KMT2D, also known as MLL2, is known to play an essential role in development, differentiation, and tumor suppression, its role in pancreatic cancer development is not well understood. Here, we discovered a novel signaling axis mediated by KMT2D, which links TGF-bêta to the activin A pathway. We found that TGF-bêta upregulates a microRNA, miR-147b, which in turn leads to post-transcriptional silencing of KMT2D. Loss of KMT2D induces the expression and secretion of activin A, which activates a noncanonical p38 MAPK-mediated pathway to modulate cancer cell plasticity, promote a mesenchymal phenotype, and enhance tumor invasion and metastasis in mice. We observed a decreased KMT2D expression in human primary and metastatic pancreatic cancer. Furthermore, inhibition or knockdown of activin A reversed the protumoral role of KMT2D loss. These findings support a tumor-suppressive role of KMT2D in pancreatic cancer and identify miR-147b and activin A as novel therapeutic targets.