Tehran University of Medical Sciences Basic & Clinical Cancer Research 2228-6527 11 1 2019 01 02 5 15 EN Nassim Faridi Department of Clinical Biochemistry, Faculty of Medical Sciences, Tarbiat Modares University Tehran, Iran Hamid Heidarzadeh Department of Clinical Biochemistry, Faculty of Medical Sciences, Tarbiat Modares University Tehran, Iran Mohammad Ali Mohagheghi Cancer Research Center of Cancer Institute, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran S. Zahra Bathaie Department of Clinical Biochemistry, Faculty of Medical Sciences, Tarbiat Modares University Tehran, Iran 2018 09 12 2018 12 16 Background: Saffron carotenoids have been known as powerful phytochemicals in breast cancer treatment. The purpose of this study was to investigate the anti-cancer properties of an important saffron carotenoid, crocin, on BT-474 which is a known HER2+ breast cancer cell line. Methods: The effect of crocin on cell viability was investigated using MTT assay. Apoptosis induction was studied via flow cytometry and Western blotting of caspase-9 and cleaved caspase-9. Involvement of unfolded protein response (UPR) was also investigated via RT-PCR study of the XBP1 gene. Results: The results showed that crocin treatment decreases the viability of BT-474 cells and induces early and late apoptosis in these cells. The mechanism of crocin action was through the induction of caspase-9 expression and cleavage. Furthermore, we found that crocin induced XBP1 gene splicing in these cells. Conclusion: The present study provides important evidence that crocin induces apoptosis in BT-474 cells. In addition, the activation of UPR may play a role in the anticancer effects of crocin. https://bccr.tums.ac.ir/index.php/bccrj/article/view/302