However, only the treatment of ESCC cells with MLN4924 at the concentration ≥ 25 μM led to cell apoptosis confirmed by alterations in cell morphology and cleavage of PARP1 (proteins including poly(ADP-ribose) polymerase-1) in an 89 kDa fragment (Figure S3). Here, PARP1 is linked to esophageal squamous cell carcinoma.