miR-203, a microRNA of multilayered epithelia, inhibits metastatic fitness in human squamous cell carcinoma. Homo sapiens

The colonization of distant organs by metastatic carcinoma cells underpins most human cancer-related deaths, including those from head and neck squamous cell carcinoma (HNSCC). We report that miR-203, a miRNA that promotes keratinocyte differentiation, is necessary and sufficient to inhibit multiple post-extravasation events during HNSCC lung metastasis, including initial survival/engraftment, escape from metastatic dormancy, and overt colonization in vivo. Restoration of miR-203 expression in established lung metastases reduces overall metastatic burden. Instead of promoting differentiation, miR-203 controls lung metastasis through direct targeting of genes involved in cytoskeletal dynamics (LASP1), ECM remodeling (SPARC), and cell metabolism (NUAK1). Expression of miR-203 and its downstream targets correlates with HNSCC overall survival outcomes, suggesting the therapeutic potential of targeting this signaling axis. Overall design: Total RNA (including small RNAs) was isolated from cultured cells stably infected in biological duplicate with either a scrambled control hairpin or miR-203. Samples were harvested in technical duplicate.