Characterization of ATM gene expression and evaluation of Reactive Oxygen Species in Silibinin-treated SKBR3 cells

Abstract Background Reactive Oxygen Species (ROS) are the small, unstable and highly reactive species, having DNA oxidizing ability. Oxidation of the DNA’s purine and pyrimidine bases can lead to single or double strands in this macromolecule. In this situation, the ATM molecule, a serine-threonine kinase, targets several proteins for phosphorylation, which causes the cell cycle to stop and the DNA damage repair begins. It has previously been proven that natural polyphenols have the cancer inhibiting properties due to their high efficacy and low side effects. Silibinin is the main herbal and medical ingredient in Milk Thistle ( Silybum marianum ) is a polyphenol flavonolignan, which has been widely considered as an antioxidant and anticancer agent. The purpose of the present study was to investigate the ATM gene expression and measurement of reactive oxygen species (ROS) in SKBR3 cell line, treated with Silibinin. Materials and Methods At first, the SKBR3 cell line was cultured in RPMI1640 culture medium and MTT assay was carried out to evaluate the Silibinin cytotoxicity. Flow Cytometry was carried out for cell cycle analysis, apoptotic induction, and ROS detection. While, Real Time PCR was used to evaluate the ATM gene expression in the Silibinin-treated and un-treated SKBR3 cells. Results Present results have shown that 150 µ M Silibinin had the most significant cytotoxicity and apoptotic induction influence after the treatment period of 48 h. Flow cytometry data have shown that Silibinin induced considerable amount of apoptosis and caused cell cycle arrest at G1/S phase and induced production of ROS. Real-time PCR results have revealed that Silibinin increased the ATM expression in SKBR3 cell line. Conclusion Silibinin causes increased ATM gene expression by inducing ROS production, which initiates cell cycle arrest and apoptotic induction in SKBR3 cells line.