miR-155 knockout experiments. Two independent miR-155 knockout clones were generated in OCI-Ly7 cells by the CRISPR-Cas9 technology. Wild-type accounts for untransduced OCI-Ly7 cells, whereas control is an OCI-Ly7 population subjected to a sgRNA not targeting the human genome. (A) Cell proliferation was determined by the trypan blue exclusion method after 48 hours of growth in wild-type, control cells, and miR-155 knockout clones. (B) miR-155 expression detected by RT-qPCR. (C) Vincristine dose-response analysis using 0.0005 µg/mL, 0.001 µg/mL, and 0.0015 µg/mL. Drug response is illustrated as percentage of living cells related to the no-drug condition. (D) Detection of Wee1 protein by western blotting. β-actin was used as loading control and Ship-1, a validated target of miR-155,⁵³  as positive control. (E) Quantification of western blot bands. Ship-1 and Wee1 levels are depicted as relative to β-actin levels. (F) Chemical inhibition of Wee1 by MK-1775. Wild-type OCI-Ly7 cells were exposed to saline, 400 nM MK-1775, 0.0015 µg/mL vincristine or 400 nM MK-1175 and 0.0015 µg/mL vincristine for 48 hours, and the number of metabolically cells were determined by 3-(4,5 dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl)-2H-tetrazolium assay. Drug response is presented as the number of cells relative to the no-drug condition. MK, MK-1775; Vin, vincristine.