SOD1 and chronic obstructive pulmonary disease: The EC50 values for upregulation of TXNRD1 and SOD1 were 2.0 and 3.1 nM, respectively, for C4X_6665 in COPD patients, with higher values for CDDO (5.7 and 4.8 nM, respectively) and GSK7 (30.4 and 31.9 nM, respectively).