Fig. 6: MCM7 mediates the effects of circKIF18A on NPC senescence under oxidative stress.

a The CCK-8 assay showed the effects of circKIF18A and sh-MCM7 on NPC viability (n = 3, three different donors; *P < 0.05; **P < 0.01). b The EdU assay revealed that MCM7 mediated the effects of circKIF18A on proliferation in H₂O₂-treated NPCs (n = 5, five different donors; scale bar: 50 μm). c and d SA-β-gal staining assay of NPCs transfected with or without circKIF18A and sh-MCM7 lentiviruses under oxidative stress (n = 3, three different donors for three individual experiments; *P < 0.05, **P < 0.01; scale bar: 50 μm). e and f MCM7 knockdown promoted G0/G1 arrest, which was rescued by circKIF18A overexpression, in NPCs under oxidative stress (n = 3, three different donors; *P < 0.05; **P < 0.01). g The protein levels of aggrecan, collagen II, MMP-13, and MMP-3 in NPCs transfected with circKIF18A, sh-MCM7, and empty lentiviruses were determined using western blotting (n = 3, three different donors). h The qRT-PCR assay showed the effects of MCM7 on the mRNA expression of ACAN, COL2A1, MMP13 and MMP3 in circKIF18A-overexpressing NPCs (n = 3, three different donors for three individual experiments; NS, no significance; *P < 0.05; **P < 0.01). i The protein levels of p53, p21, and p16 were measured using western blotting. NPCs were stably transfected with circKIF18A, sh-MCM7, and empty lentiviruses (n = 3, three different donors). j Western blot assays showed the effects of MCM7 on the protein levels of cyclin D1, CDK4, p-RB and RB in NPCs treated as described above (n = 3, three different donors). k The effect of p53 knockdown on the p21 level in sh-circKIF18A NPCs (n = 3, three different donors). l and m Representative images of the DCFH-DA staining assay in NPCs with circKIF18A overexpression or MCM7 knockdown under oxidative stress (n = 5, five different donors; NS no significance. Scale bar: 20 μm). All data are presented as the mean ± SD values.