Fig. 2

CircPLPP4 expression level is associated with poor prognosis in OC patients and silencing of circPLPP4 facilitate CDDP sensitivity of OC cells. A Representative sections of circPLPP4 in 166 OC tissues using in situ hybridization. B The distribution of circPLPP4 in Platinum resistant and Platinum sensitive patient specimens detected by in situ hybridization (ISH). χ2 test was used. C circPLPP4 is remarkably relevant with the response status of chemotherapy. χ2 test was used. D Kaplan–Meier analysis of 5-year Relapse-free survival (RFS) in OC patients stratifed by low and high circPLPP4 levels (n = 166, log-rank test). HR, hazard ratio. E Multivariate Cox regression analysis to assess the significance of the correlation between circPLPP4 expression signature and OS in the presence of other important clinical variables. G, H ISH analysis of circPLPP4 expression in OC tissues (92 Platinum sensitive OC patients and 72 Platinum resistant OC patients). I Staining index of circPLPP4 in 166 OC tissues (92 Platinum sensitive OC patients and 72 Platinum resistant OC patients). J qRT-PCR analysis of circPLPP4 and linear PLPP4 expression in the indicated OC cells. GAPDH act as a control. K MTT cell viability assay of CDDP in the indicated cells. K, L Representative images and quantification of colony number of the indicated cells. (M) Western blot analysis shows apoptotic proteins in the indicated cells (GAPDH was selected as the loading control). N Western blotting analysis of level of γ-H2AX and BRCA1 in the indicated cells. (GAPDH was acted as the loading control). O FACS analysis of Annexin V / PI staining (left) and quantification (right) of indicated cells treated with vehicle or CDDP (5 μM) after 24 h. P Representative images (left) and quantification (right) of γ-H2AX in the indicated OC cells treated with CDDP (5 μM) after 24 h. * P < 0.05, ** P < 0.01, *** P < 0.001, **** P < 0.0001, ns indicates no significance. Each error bar represents the mean ± SD of three independent experiments