Cytokine production by blood cells and tumor samples and its coupling to microRNA expression in breast cancer patients

Abstract

Breast tumors show a complex structure and are highly heterogeneous. The study of cytokines, which exert great influence on tumor cells, and microRNAs, which, along with their influence on the proliferation and migration of neoplastic cells, may affect the work of cytokines, will contribute to a deeper understanding of pathological processes occurring in breast cancer. The aim of our work was to analyze the relationship of cytokine production with expression of miR-181a and miR-25in patients with invasive breast carcinoma of a non-specific type (IBC NST) with various molecular subtypes.Patients with IBC NST were divided into five subgroups according to the molecular genetics subtype of the tumor classified by immunohistochemical analysis of estrogen receptor (ER), progesterone (PR), epidermal growth factor 2 (HER2) and proliferation marker Ki-67. Using enzyme immunoassay, the concentration of 14 cytokines was determined in the supernatants of immunocompetent blood cells and tumors: IL-2, IL-6, IL-8, IL-10, IL-17, IL-18, IL-1β, IL-1ra, TNFα, IFNγ, G-CSF, GM-CSF, VEGF and MCP-1. The expression of miR-181a and miR-25 microRNAs isolated from the patients’ blood serum was evaluated using digital droplet polymerase chain reaction (ddPCR).In the luminal A subtype, cytokine concentrations and expression of miR-181a and miR-25 are significantly lower compared to other subtypes. Patients with the luminal B HER2-negative subtype were characterized by significantly increased expression of both studied microRNAs, especially when compared with the luminal A subtype. At the same time, patients with a triple negative molecular subtype, on the contrary, were characterized by high concentrations of cytokines in the supernatants of tumor samples and blood cells compared to   other subtypes. In the general group of patients with IBC NST, direct correlations were found between the expression of both studied microRNAs and the concentration of vascular endothelial growth factor (VEGF) in the supernatant of tumor samples, which may presume mutual interactions existing between miR-181a and miR-25, and the process of angiogenesis in the tumor.The levels of cytokines in blood supernatants and tumors in invasive breast carcinoma may vary, depending on distinct molecular subtypes of the tumor. Moreover, they also have direct links with the levels of miR-181a and miR-25 in blood serum. Particularly noteworthy were the results of measuring the cytokines and microRNAs concentrations in luminal A, luminal B HER2-negative and triple negative molecular subtypes.