In contrast to the lack of evidence supporting the involvement of PI3K and Akt and MAPK signaling, ATP-competitive mTOR inhibition had a profound inhibitory effect on TGF-β1-induced collagen synthesis (with the most potent and selective compounds tested displaying an IC50 within the nanomolar range) in control and IPF fibroblasts. This evidence concerns the gene TGFB1 and idiopathic pulmonary fibrosis.