The Effect of Endurance Training on MiR-155 Expression, STAT3 Gene Expression, and Interleukin 6 Protein in Mice with Breast Cancer

Endurance training has an important role in the prevention and adjuvant therapy of breast cancer. The aim of the present study was to investigate the role of endurance training on miR-155 expression, signal transducer and activator of transcription-3 (STAT3) gene expression, and interleukin 6 (IL-6) protein in breast cancer tumor in mice. In this study, 16 female Balb/C mice were randomly divided into exercise-tumor (ET) and rest-tumor (RT) groups. The mice were oriented in the environment and one million estrogen-dependent breast cancer cells (MC4L2) were injected into each mouse. Subsequently, the ET group performed endurance exercise, 5 days per week for 6 weeks. Tumor volume was measured by a digital caliper weekly. Finally, the mice were sacrificed and tumor tissue was removed and kept in -70°C. Then, RNA was extracted by the Trizol protocol and complementary DNA (cDNA) was synthesized according to guidelines of the Kit Company. Consequently, the real-time PCR method was performed and data was collected. Significant differences were observed between the ET and RT groups in the STAT3 gene expression, miR-155 expression, and IL-6 protein (P < 0.05). These results were consistent with tumor growth rate. Exercise can reduce miR-155 expression, STAT3 gene expression, and IL-6 protein in tumor tissue. Due to the reduction in miR-155 expression, STAT3 gene expression, and IL-6 protein in the ET group, it can be claimed that endurance training can be used as adjuvant therapy by decreasing of oncogenic and inflammation factors.