DDIT3 and colorectal carcinoma: The co-treatment of CRC cell lines with the chemical chaperone 4-phenyl butyric acid (4-PBA)—a compound known to alleviate ER stress—reduced CHOP nuclear localization, and significantly rescued spiperone-induced cell death, suggesting that ER stress and CHOP activity are directly involved in spiperone’s cytotoxicity (Figure 9a–c).