Fig. 2

Biological functions of RRM2 in prostate cancer. a qRT‒PCR suggested a notable overexpression of RRM2 in PCa tumor tissues. The expression of RRM2 was analyzed in 30 BPH tissues and 60 pairs of PCa and adjacent normal tissue samples by qRT‒PCR. b Expression of RRM2 was analyzed and compared between the low Gleason score group (n = 37) and the high Gleason score group (n = 23). c RRM2 is highly expressed in prostate tumor tissues with advanced Gleason scores. Representative images show RRM2 expression in BPH tissues and prostate tumor tissues by IHC staining. The staining intensity of RRM2 was scored as 0 to 5 (0: no staining, 1: very weak staining, 2: weak staining, 3: medium staining, 4: strong staining, 5: very strong staining). Magnification: 200X. d RRM2 expression was overexpressed or knocked down in PCa cell lines, and the CCK-8 assay showed the proliferation curve of the cells. e and f Cell proliferation was assessed by colony formation assay in RRM2 overexpression or knockdown PCa cell lines. g RRM knockdown inhibited the proliferation of PCa cells, as determined by EdU staining assay. RRM2 was knocked down in 22Rv1 and LNCaP cells, and after 48 h, the cells were subjected to EdU staining. Numbers of proliferative cells were counted by ImageJ. Red color indicates positively stained cells. Magnification: 100X. h RRM2 knockdown induced cell cycle arrest in G1 phase. The cell cycle was measured by FACS in control or RRM2 knockdown 22Rv1 and LNCaP cells. i IF staining assay suggested that RRM2 knockdown remarkably induced DBS in PCa cells after DTX treatment. γ-H2AX foci were measured by IF assay in control or RRM2 knockdown PCa cells 30 min or 24 h after DTX treatment (10 nM). Green indicates positively stained cells. Magnification: 200X. ns indicates not significant, * indicates p < 0.05, ** indicates p < 0.01