Fig. 1: Mesothelial cells induce the growth of OvCa cells.

A A schematic model of OvCa cells cocultured with primary mesothelial cells in a transwell plate (co-culture, top) or cultured in mesothelial cells-conditioned media (CM) (bottom). B SKOV3 and OVCAR3 cells were co-cultured with mesothelial cells or incubated with mesothelial cell-derived conditioned medium (Meso-CM) in the co-culture transwell system for the indicated time periods followed by trypan blue staining and counting cells. SKOV3 and OVCAR3 cells alone served as control. Error bar represent Mean +/- SD; ns - not significant; *P < 0.05, **P < 0.01, ***P < 0.001 by ANOVA for repeated measures. C OvCa cells were cultured in the conditioned medium with a different ratio of culture medium and supernatants from mesothelial cells (ratios 1:1, 1:2, 1:4, 2:1, and total supernatants from the mesothelial cell culture, respectively) followed by quantitation of cells. Error bar represent Mean SD + /-, *P < 0.05 by repeated measures of ANOVA. D OVCAR3 and SKOV3 cells were used for immunofluorescence staining of Ki-67 on day 5 (post-culture) in the indicated three groups. The bar graph below shows the quantification of the proportion of Ki-67-positive cells in each group. Scale bar 100 μm, Error bar represent Mean +/- SD; *P < 0.05, **P < 0.01 by one-way ANOVA. E Matrigel invasion assay of SKOV3 and OVCAR3 cells in the indicated three groups. Scale bar 100 μm, n = 3. The graph below represents the quantification of the number of invaded cells per field, Error bar represents Mean +/- SD; *P < 0.05, **P < 0.01 by one-way ANOVA. F Assessment of the effect of Meso-CM or mesothelial cell co-culture on the sensitivity of SKOV3 and OVCAR3 cells to cisplatin. Cell viability is normalized to the untreated control group and statistical analysis was compared with SKOV3 and OVCAR3 monoculture group (n = 3), Error bar represents Mean +/- SD; ns= not significant, *P < 0.05, **P < 0.01 by one-way ANOVA. G SKOV3 and OVCAR3 cells were treated with the indicated concentrations of cisplatin for 48 hours and the proportion of apoptotic cells was determined by Annexin V-PI flow cytometry. Quantification of percentages of apoptotic cells in the indicated groups. Each group was statistically analyzed and compared to the untreated control group (n = 3), Error bar represents Mean +/- SD; *P < 0.05, **P < 0.01 by one-way ANOVA. H Effects of mesothelial cell co-culture on cisplatin treatment resistance of SKOV3 cells in vivo. SKOV3 cells were either cultured alone or were co-cultured with human mesothelial cells in vitro, and then were injected subcutaneously into immunocompromised mice. Once tumors were palpable, mice were treated with cisplatin (5 mg/kg body weight) or DMSO twice a week for 3 cycles. Representative of resected tumor images and tumor weight (bar graph) at the end point is shown (n = 1, 2, 3 mice per group). ns = not significant; ***P < 0.01 by two-way ANOVA. Data in the figure represent average and +/-SEM; P- values were determined using the Student’s t-test unless otherwise indicated.