CHOP is a key regulator of ER stress-induced apoptosis. It
regulates gene expression by forming hetero-dimers with other
proteins from the C/EBP family or other transcription factors,
acting as an activator or inhibitor of gene transcription [43]. In
response to ER stress, DNA damage or other stress conditions,
CHOP is induced to drive cell apoptosis by a variety of
mechanisms including induction of oxidative stress and down-
regulation of the anti-apoptotic protein Bcl2 [44]. The role of
CHOP in fucoidan-induced cell apoptosis in MDA-MB-231 and
HCT116 cells was verified by the fact that CHOP knockdown
prevented DNA damage and cell death from fucoidan treatment.
Therefore, the fucoidan-induced CHOP is responsible for
fucoidan-induced cell apoptosis. Fucoidan treatment may result
in the excessive phosphorylation of eIF2a to activate CHOP for
the induction of cell apoptosis in cancer cells