The Effect of Sirtuin 2 (Sirt2) Overexpressing Bone Marrow Mesenchymal Stem Cells on the Growth of Human Epidermal Growth Factor Receptor 2 (Her-2) Breast Cancer Cells and Its Mechanism

Our study investigates the effect of high expression of Sirt2 in MSCs (MSCs-Sirt2) on Her-2 breast cancer cell proliferation. A mouse subcutaneous xenograft tumor model was established and MSCssirt2 analysis was performed on nude mice. TUNEL staining, flow cytometry, western-blot, real-time PCR and immunohistochemistry were used to detect cancer cell apoptosis. The number of NK cells infiltrated by flow cytometry detected the tumor tissue of tumor-bearing mice, and its killing activity on tumor-bearing mice was detected by isotope labeling and release method. The levels of TNF-α, IFN-γ, IL-8, IL-6 and IL-10 were detected by ELISA. Caspase-3 level was decreased in the MSCs group ( P <0.01) while increased in the MSCs-sirt2 group ( P <0.001). However, PCNA expression showed an opposite profile in the Her-2 group and MSCs-sirt2 group compared to Caspase-3 level ( P <0.01). The tumor volume and weight in the MSCs-sirt2 group was significantly reduced ( P < 0.01), while increased in the MSCs group significantly ( P < 0.05). The number of Ki-67-positive tumor cells in MSCs-sirt2 group was significantly reduced ( P <0.01) and increased in MSCs group ( P < 0.001) with oppositive number of TUNEL-positive tumor cells in the MSCs-sirt2 group and MSCs group ( P <0.01). IFN-γ level showed an upward trend ( P <0.001). The NK cell toxicity of MSCs-Sirt2 group was significantly higher ( P <0.001). MSCs-Sirt2 has an inhibitory effect on Her-2 breast cancer cell growth by enhancing the local inflammatory response of NK cells.