Feature of Experimental Breast Cancer Induced by Intermammary Administration of N-Methyl-N-Nitrosourea in Wistar Rat

Abstract

Abstract. Breast cancer is the leading cause of cancer death in women worldwide due to the complicated etiology involving both genetic and environmental factors. BC was induced by N-Methyl-N-Nitrosourea administration intermammary in Wistar female. Studied frequency of development of NMU-induced BC, phenotype of BC cells, phenotype of MSC from mammary gland tissue, quantity and quality of immunocompetent cells, expression of miRNAs, hormone levels and cytokines were done for estimate sensitivity to chemotherapy.We showed that MNU-induced BC developed in 90%, immunohistochemical similar to human luminal A type of BC with higher proliferation activity. We estimated significantly increased count of BC-MSC with CD45+CD90-, and CD45+CD90+, and CD45-CD90+ phenotype in animal with MNU-induced BC. Chemotherapy caused changes in quality and quantity of immunocompetent cells, decrease of prolactin and luteinizing hormone levels, and some changes in expression of pro-oncogenic or tumor-suppressing miRNAs. In MNU-induced BC animal were observed increased serum levels of pro-inflammatory cytokines. In regional lymph nodes found increased count of macrophages and presence of tumor cells. Intermammary administration of NMU possessed to breast cancer development with similarities to human luminal B phenotype. This MNU-induced breast cancer may serve as a model to study efficiency of chemotherapy.