Ambivalent roles of miRNAs in cancer development via modulating tumor-associated innate immune cells

The tumor microenvironment (TME), comprising malignant and non-transformed cells like immune cells, endothelial cells, and cancer-associated fibroblasts, significantly affects tumor growth and progression. Tumor cells manipulate the TME by releasing chemokines and inhibitory cytokines, reprogramming surrounding cells to support their survival and evade immune detection. Innate immune cells within the TME play dual roles, either promoting or inhibiting tumor progression, impacting immunotherapy outcomes. Recent studies highlight the influence of innate immune cells in shaping the TME and the pivotal role of tumor-derived microRNAs (miRNAs) in modulating these cells. miRNAs regulate gene expression and enhance tumor immune evasion, angiogenesis, drug resistance, and invasion. Their tumor-specific expression patterns suggest potential as biomarkers and therapeutic targets. This study focuses on how miRNAs affect innate immune cells like macrophages, dendritic cells, myeloid-derived suppressor cells, and natural killer cells, contributing to immunosuppressive or immunogenic environments. Understanding miRNA-mediated interactions between cancer and immune cells opens new possibilities for improving targeted immunotherapy and advancing cancer treatments.