RNA-seq analysis of A549 cells harboring Smad3 R104K A105P mutation.

Transforming growth factor-beta (TGF-beta) transmits signals that facilitate cancer progression. Especially, epithelial-mesenchymal transition (EMT) induced by TGF-beta is considered to crucially contribute to the malignant phenotype of cancer cells. Here we report that the EMT-associated cellular responses induced by TGF-beta are mediated through distinct signaling pathways that diverge at Smad3; cell motility and epithelial marker downregulation are Smad3-dependent while mesenchymal marker induction is not. Furthermore, using a chimeric protein approach in SMAD3 knockout A549 cells, we found that the beta 4 region in the MH1 domain of Smad3 is indispensable for TGF-beta–induced cell motility, but not for epithelial marker downregulation. A transcriptome analysis was performed using A549 cells expressing Smad3 mutant of the MH1 domain. RNA-seq analyses were performed in wild type- and mutant Smad3 (R104K A105P)-expressing A549 lung adenocarcinoma cells stimulated with TGF-beta.