Fig 2: Circ_0002360 regulated DDP resistance in A549/DDP xenograft mice by miR-6751-3p/ZNF300 axis. A549/DDP xenograft model of the DDP + sh-NC or DDP + sh-circ_0002360 group was established in mice. (a–c) Tumor volume (a) and weight (b,c) were measured. (d) Circ_0002360, miR-6751-3p and ZNF300 levels in tissues were examined by RT-qPCR. (e) ZNF300, MRP1 and p-gp protein detection was performed by western blot. (f) IHC assay was used for protein analysis of Ki67 and ZNF300 in tumor tissues. *p < 0.05

Fig 3: Circ_0002360 acted in DDP‐resistant lung cancer cells via upregulating ZNF300. Transfection of sh‐NC, sh‐circ_0002360, sh‐circ_0002360 + vector and sh‐circ_0002360 + ZNF300 was performed in A549/DDP and H1299/DDP cells. (a) IC50 of DDP was determined through CCK‐8 assay. (b,c) The proliferation ability was examined through colony formation assay (b) and EdU assay (c). (d) The migration potential was analyzed through transwell assay. (e,f) Cell apoptosis was assessed through flow cytometry (e) and caspase 3 activity (f). (g,h) MRP1, P‐gp and Bax levels were detected through western blot. *p < 0.05

Fig 4: ZNF300 downregulation inhibited DDP resistance and lung cancer progression. A549/DDP and H1299/DDP cells were performed with transfection of sh-NC or sh-ZNF300. (a) RT-qPCR was conducted for ZNF300 protein detection. (b) CCK-8 assay was conducted for measuring the IC50 of DDP. (c,d) Colony formation assay (c) and EdU assay (d) were conducted for proliferation examination. (e) Transwell assay was conducted for assessment of migration. (g,h) Flow cytometry (g) and caspase 3 activity (h) were conducted for determination of apoptosis. (i,j) Western blot was conducted for protein analysis of MRP1, P-gp and Bax. *p < 0.05

Fig 5: Silencing circ_0002360 reduced DDP resistance and suppressed malignant phenotypes of DDP-resistant lung cancer cells. A549/DDP and H1299/DDP cells were transfected with sh-NC or sh-circ_0002360. (a) RT-qPCR was applied to determine the circ_0002360 and RUNX1 levels. (b) A CCK-8 assay examined IC50 of DDP. (c,d) Colony formation assay (c) and EdU assay (d) were applied to analyze cell proliferation. (e) Transwell assay was applied to evaluate cell migration. (g,h) Flow cytometry (g) and caspase 3 activity (h) were applied to assess cell apoptosis. (i,j) Western blot was applied to measure the protein levels of MRP1, P-gp and Bax. *p < 0.05