As an apoptosis indicator, CHR plus TMZ treatment also increased cleavage of PARP1 (which plays a critical role in DNA repair) (D'Amours et al., 2001), aligning with previous findings that CHR inhibits PARP in colorectal cancer (Lin et al., 2018) and hepatocellular carcinoma (Xu et al., 2017). Here, PARP1 is linked to hepatocellular carcinoma.