High-throughput screening of Sirtuin family of genes in breast cancer.

Mammalian Sirtuins have been shown to perform distinct cellular functions and deregulated expression of these genes was reported to be involved in the development of various malignancies including breast cancer. An increasing number of evidence indicates that Sirtuins have both tumor promoter and tumor suppressor functions. However, the roles of Sirtuins have not been well-reported in breast cancer. In the present study, quantitative expression levels of Sirtuins (SIRT1-7) in breast cancer patients and breast cancer cell lines (MCF-7 and SKBR3) and control cell line (CRL-4010) were assessed by using a high-throughput real-time PCR method. As a result, Sirtuins were found to be differentially expressed in breast cancer tissues and cancer cell lines. Particularly, expressions of SIRT1 and SIRT4 were found to be significantly down-regulated in breast cancer tissues and SKBR3 breast cancer cells. In contrast, SIRT2, SIRT3, and SIRT5 genes were shown to be up-regulated in our study. Although SIRT6 and SIRT7 were also up-regulated in breast cancer tissues, these expression changes were statistically insignificant. Additionally, SIRT2, SIRT3, SIRT5, SIRT6 and SIRT7 were found to be differentially expressed in breast cancer cell lines. Yet, these changes were not well-correlated with tissue expression levels. In conclusion, Sirtuin family of genes shows differential expressions in breast cancer tissues and cells and SIRT1 and SIRT4 seem to play key tumor suppressor roles in breast cancer development. Herein, we report expression levels of Sirtuin family of genes in both breast cancer tissues and cancer cell lines simultaneously.