TGFB1 and lung adenocarcinoma: The team further found that Tan IIA inhibits SiO2-induced expression of TGF-β1 and its downstream p-Smad3 in human lung adenocarcinoma cell line (A549) and human bronchial epithelial cell (HBE) cells, upregulates the expression level of Smad7, and increases the expression of Nrf2, HO-1, and NQO-1, thereby inhibiting the TGF-β1/Smad signaling pathway and EMT (Feng et al., 2020).