In vitro treatment of triple-negative breast cancer cells with an extract from the Coriolus versicolor mushroom changes macrophage properties related to tumourigenesis.

Macrophages, the most abundant cells that participate in tumour progression, are the subject of a number of anticancer therapy approaches. Our previous results revealed that an extract of the fungus Coriolus versicolor (CV) has anti-cancer and immunomodulatory properties. The aim of the present study was to investigate whether CV extract-treated triple-negative breast cancer (TNBC) cells can release factors that can reprogram macrophages from pro-tumourigenic to anti-cancer subtypes. RAW 264.7 macrophages were cultured in a conditioned medium (CM) from non-treated 4T1 breast cancer cells (CM-NT) or CV extract-stimulated cells (CM-CV). After treatment, the following macrophage properties were evaluated: cell viability; M1/M2 phenotype (enzyme activities: iNOS and arginase 1; and expression of CD molecules: CD80 and CD163); cytokine concentrations: IL-6, TNF-α, IL-10, TGF-β, MCP-1 and VEGF; migration level; and ROS production. The results revealed that, compared with normal cells, TNBC cells stimulated with CV extract create a microenvironment that promotes a decrease in macrophage viability and migration, intracellular ROS production, and pro-angiogenic cytokine production (VEGF and MCP-1). Moreover, CM-CV decreased the expression of M2 macrophage markers (arginase 1 and CD163; IL-10 and TGF-β) but upregulated the expression of M1 cell markers (iNOS and CD80; IL-6 and TNF-α). We concluded that CV extract modifies the tumour microenvironment and changes macrophage polarisation toward functioning as an anti-tumour agent. Therefore, it is promising to use in the treatment of TNBC-associated macrophages.