Overexpression of Metastatic Related MicroRNAs, Mir-335 and Mir-10b, by Staphylococcal Enterotoxin B in the Metastatic Breast Cancer Cell Line

One of the advanced cancer therapy strategies is immune-stimulating compound based immunotherapy Staphylococcal enterotoxin B (SEB) is one of the potent superantigens, which can efficiently activate antitumor immune response to eradicate tumor growth and inhibit metastasis. Herein, we evaluated the effect of SEB on the expression of two master microRNAs, mir-335 and mir-10b, involved in metastasis. A metastatic breast cancer cell line MDA-MB231was treated with four differentconcentrations of SEB, including 10, 102, 103 and 104 ng/ml, for 24 and 48 hours. To identify the cytotoxic effect of SEB, treated cells were examined by MTT assay. The stem loop RT-PCR (TaqMan) was used to analyze the mir-335 and mir-10b expression. Results showed that SEB significantly increased the expression of mir-335 bothafter 24 and 48 hours (pv < 0.001 and pv < 0.05, respectively). No significant differences were found in the mir-10b expression. Moreover, our findings demonstrated no cytotoxic effect of SEB on the treated cells. Our results suggest that SEB probably induces its anti-metastatic effect via the expression regulation of the main genes which contributes to metastasis.