USP1 and neoplasm: It was demonstrated that circ‐USP1 knockdown combined with miR‐194‐5p overexpression significantly increased the apoptosis rate of U87 glioma cells induced by Dox, compared with the circ‐USP1 knockdown or miR‐194‐5p overexpression alone, suggesting that the treatment of circ‐USP1 and miR‐194‐5p in combination could enhance Dox‐induced anti‐tumour effect by promoting its penetrating capability across BTB.