piR-4447944 promotes androgen-independent growth of PCa cells by targeting NEFH. A, The NEFH protein level was restored by co-transfection with NEFH-overexpression (NEFHoe) plasmid in piR-4447944-overexpressed LNCaP cells and 22Rv1 cells. Statistical histograms were shown in the right panel. B-D, Restoration of NEFH expression attenuated the enhanced androgen-independent growth of PCa cells induced by piR-4447944 under CS-FBS conditions, as indicated by CCK8 assay (B), EdU incorporation assay (C) and cell cycle assay (D). The cell proliferation index was calculated as (S+G2/M)/(G0/G1+S+G2/M) x 100%. Results are presented as mean ± SD. *p < 0.05; **p < 0.01, ***p < 0.001, ****p < 0.0001. Data were obtained from at least three independent experiments.