Radiotherapy is one of the most common and effective treatments for localized
cancer. However,
radiotherapy kills
tumor cells while causing damage to surrounding normal cells. Enhancing the radiation sensitivity of
tumor cells and reducing the radiation damage to normal cells is a difficult problem. Here, we find that the expression of a human
microRNA (
miRNA), hsa-miR-222, is upregulated in response to ionizing radiation. TargetScan analysis shows that the
3' UTR of CD47 is potentially targeted by miR-222. This prediction was validated by
luciferase reporter and mutation assays. It was demonstrated that miR-222 negatively regulates CD47 expression at
mRNA and
protein levels, and overexpression of the miR-222 enhances
cancer cell radiosensitivity by the CD47-pERK pathway in
cancer cells. Our findings enrich the complex relationship between
miRNA and CD47 in irradiation stress and shed light on the potential of
miRNAs both for direct
cancer therapeutics and as tools to sensitize
tumor cells to
radiotherapy.