CPUL1 is a TrxR inhibitor, which shows proliferation-inhibitory and anti-metastatic activity against A549 cells. CPUL1 influences EMT (epithelial-mesenchymal transition) via inducing ROS-mediated ERK/JNK signaling by inhibiting TrxR1 enzyme activity. CPUL1 in combination with α-Lipoic Acid or Dithiodipropionic acid is more effective.