Fig. 6

CircRNA-CREIT attenuated SG formation via the PKR/eIF2α axis. A PKR reversed the effects of circRNA-CREIT in promoting chemosensitivity. Cell viability was detected MTT assays. The IC50 and the 95% CI of cells with different treatments are shown. B Colony formation assays presenting the roles of PKR in mediating the functions of circRNA-CREIT. C Immunofluorescence staining for the SG marker EIF3A under DOX treatment (for 24 h). Representative images are shown and the percentage of cells with SGs and the number of SGs per cell were calculated. D Western blotting assay showing that circRNA-CREIT inhibited p-eIF2α expression and circRNA-CREIT knockdown increased p-eIF2α levels in TNBC cells. E Immunofluorescence staining for p-eIF2α after circRNA-CREIT overexpression or knockdown with or without DOX treatment (for 24 h). Quantitative analyses were performed using Image J, and the groups treated with empty vectors and PBS were used as controls. F Subcellular localization of RACK1 and endogenous SG markers EIF3A and EIF4G1 under DOX treatment. Cells were transfected with RACK1-pmCherry-C1 plasmids, treated with DOX for 24 h and subjected to immunofluorescence. Colocalization analysis for RACK1 and SG markers along the indicated line was performed by ImageJ. G Western blotting analysis of the co-IP assay showing that the interaction between RACK1 and MTK1 was blocked by DOX treatment. H Co-IP assay and the subsequent Western blotting assay verified that circRNA-CREIT restored the binding of RACK1 and MTK1. Scale bars = 20 μm. Three independent experiments were conducted for each result. *p < 0.05; **p < 0.01, ***p < 0.001 compared with the controls