Summary. Mesenchymal stem cell (MSC)-dependent biological effects in the tumor microenvironment mainly rely on the activity of MSC-sourced microRNAs (MSC-miRNAs) which modulate protein synthesis in target tumor cells, endothelial cells and tumor-infiltrated immune cells, regulating their phenotype and function. Several MSC-sourced miRNAs (miR-221, miR-23b, miR-21-5p, miR-222/223, miR-15a miR-424, miR-30b, miR-30c) possess tumor-promoting properties and are able to enhance viability, invasiveness and metastatic potential of malignant cells, induce proliferation and sprouting of tumor endothelial cells and suppress effector functions of cytotoxic tumor-infiltrated immune cells, crucially contributing to the rapid growth and progression of tumor tissue. On the contrary, MSCs also produce “anti-tumorigenic” miRNAs (miR-100, miR-222-3p, miR-146b miR-302a, miR-338-5p, miR-100-5p and miR-1246) which suppress tumor growth and progression by: up-regulating expression of chemo-resistance-related genes in tumor cells, by suppressing neo-angiogenesis and by inducing generation of tumorotoxic phenotypes in tumor-infiltrated lympho-cytes. In this review article, we summarize the current knowledge about molecular mechanisms that are responsible for MSC-miRNA-dependent alterations of intracellular signaling in tumor and immune cells and we discuss different insights regarding the therapeutic potential of MSC-derived miRNAs in cancer treatment. Histol Histopathol 38, 1373-1379 (2023)

Key words: Mesenchymal stem cells, MicroRNAs, Tumor, Angiogenesis, Anti-tumor immunity

DOI: 10.14670/HH-18-633

©The Author(s) 2023. Open Access. This article is licensed under a Creative Commons CC-BY International License.