PCNA and rheumatoid arthritis: In order to examine the rescue effect associated with the overexpression of sirt6 on the overexpression of PVT1 in RA-FLSs, the expression of TNF-α, IL-1β, IL-10, IL-4, Ki67, PCNA, Bcl-2, Bax and caspase-3 in the oe-PVT1-NC + oe-sirt6-NC, oe-PVT1 + oe-sirt6-NC and oe-PVT1 + oe-sirt6 groups was measured by ELISA, RT-qPCR, western blot analysis, EDU staining and flow cytometry to analyze the effect of PVT1 on RA-FLS proliferation, inflammation and apoptosis.