Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 50 5 2021 04 30 1037 1047 Abolfazl Fattah Research Center for Health Sciences and Technologies, Semnan University of Medical Sciences, Semnan, Iran Ali Morovati Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran Zahra Niknam Student Research Committee, Department of Clinical Biochemistry, Faculty of Medicine, Ahvaz Jundishapor University of Medical Sci-ences, Ahvaz, Iran Ladan Mashouri Department of Genetics, Faculty of Sciences, Shahrekord University, Shahrekord, Iran Amirhooman Asadi Veterinary Medicine, Faculty of Veterinary Medicine, Karaj Branch, Islamic Azad University, Karaj, Iran Shirin Tvangar Rizi Department of Biology, Faculty of Basic Sciences, Lorestan University, Khorramabad, Iran Mojtaba Abbasi 1. Veterinary Medicine, Faculty of Veterinary Medicine, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran 2. Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran Fatemeh Shakeri Nursing and Midwifery Department, Jahrom University of Medical Sciences, Jahrom, Iran Omid Abazari Department of Clinical Biochemistry, School of Medicine, Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran 2019 07 07 2019 11 03 Background: Piperine is a natural compound obtained from the Piper nigrum that exhibits anti-proliferative and anti-cancer activity in cancer cell lines. We analyzed the cytotoxic effect of piperine combined with cisplatin compound in the human MCF-7 breast cancer cell line and the underlying mechanism. Methods: The present in vitro study was performed on MCF-7 cell line in Jahrom University of Medical Sciences between, Jahrom, Iran from 2016 to 2017. Cultured MCF-7 cells were seeded into four groups: a control group (untreated group), a group treated with cisplatin, a group treated with piperine and a group treated with cisplatin and piperine. Cell viability was analyzed using the MTT assay method. Flow c-ytometric analysis was investigated for apoptosis. The mRNA and protein expression of the apoptotic regulators p53, Bcl-2, Bax, caspase 3 and caspase 9 were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting analysis. Results: Piperine (20 and 30 µM) in combination with cisplatin (5, 10 and 15 µM) for 24 h synergistically inhibited cell viability of MCF-7 breast cancer cells more than piperine and cisplatin used alone. Synergistic anti-breast cancer activities cisplatin (5 µM) and piperine (20 µM) were via inducing apoptosis. Piperine (20 µM) and cisplatin (5 µM) for 24 h induce apoptosis strongly through reduction of Bcl-2 and increase of caspase 3, p53, caspase 9, and Bax. Conclusion: Piperine in combination with cisplatin could trigger p53-mediated apoptosis more effective than cisplatin alone in MCF-7 breast cancer cells, reducing the toxic dose of cisplatin used in cancer chemotherapy. https://ijph.tums.ac.ir/index.php/ijph/article/view/17693 https://ijph.tums.ac.ir/index.php/ijph/article/download/17693/7232