Study Of The Metastasis Suppression And The Immune Response Induced By Cooling And Heating Treatment On Breast Cancer

Breast cancer is the most common malignant tumor in women and metastasis isthe major cause of cancer-related death. Lumpectomy plus radiation or chemotherapyfor breast cancer in clinic has poor prognosis with high side effects and ignores thesystemic immune response. The ability of immunotherapy to induce an effectiveanti-tumor immunity is severely affected by tumor-induced immunosuppressivemicroenvironment. In recent years, thermal treatment via either freezing or heating, isgaining more interests because of its low invasiveness relatively, low cost and thestimulation of immune response. Combining both of liquid nitrogen (LN2) coolingand radiofrequency (RF) heating, a novel system of cooling and heating treatment hasbeen developed in our laboratory.In this study,4T1murine mammary carcinoma in female BALB/c mice wastreated by cooling and heating system. The therapeutic effect was evaluated and theinfluence on pulmonary metastasis after the treatment was observed by H&E staining.Then the changes of immune cells in spleen, peripheral blood and metastatic lungwere detected by flow cytometry. After that, immunofluorescence andimmunohistochemistry techniques were utilized to analyze the changes of immunecells, the necrotic cells and the release of Hsp70in the primary tumor. At last, theconcentration change of Hsp70in serum was determined by ELISA.The results showed that cooling and heating treatment enhanced the survival rateof tumor-bearing mice and inhibit the pulmonary metastasis significantly. Thereduction of immunosuppressive cell (MDSCs) level and the increase of effective Tcell in spleen, blood and lung proved that the treatment effectively alleviated theimmuno-suppressive microenvironment and induced a systemic anti-tumor immuneresponse against cancer. And the greatest extent of local tumor necrosis in tumortissue and the release of Hsp70from tumor to peripheral blood indicated a possiblemechanism through which the local thermal stimulation on the primary tumor wasextended to systemic immune response and the inhibition of pulmonary metastasis.