Fig. 5
The tumour-promoting effect of MSCs on OC via the PAF/PAFR pathway in vivo. a The tumour volume was determined in mice, and the data represent the average (+SD). Student’s t-test was used to compare tumour sizes among the different groups; p < 0.05 indicates a statistically significant difference. MSCs alone were not tumourigenic, while they significantly promoted the growth of SKOV3-derived subcutaneous tumours. The PAFR antagonist WEB2086 blocked this effect. Compared with the SKOV3 + WEB2086 group, the SKOV3 + MSC + WEB2086 group exhibited a significantly larger tumour volume, indicating that the PAFR inhibitor could not completely inhibit the tumour-promoting effect of MSCs. The following row contains representative photographs of mice injected with (from left to right) 1. LS: MSCs/RFP, RS: MSCs/RFP; 2. LS: SKOV3 cells, RS: SKOV3 cells; 3. LS: SKOV3 cells, RS: SKOV3 cells + MSCs/RFP (1:2); and 4. LS: SKOV3 cells, RS: SKOV3 + MSCs/RFP (1:2), treated with WEB2086 at 1 mg/kg.d by intraperitoneal injection for 2 weeks. b High PAFR expression in tumour tissue from mice injected with SKOV3 cells verified by IFC (20×). c Frozen sections were stained with DAPI and observed under a confocal microscope. MSCs/RFP could be visualised in the tumour stroma in the co-injection groups. HE-stained frozen tumour sections were photographed under a microscope (20× or 40×). d After MSC injection, the concentration of PAF in the tumour site was significantly higher than that in peripheral blood; a 10-fold upregulation of PAF was observed when MSCs and SKOV3 cells were co-injected at a ratio of 2:1 compared with that when SKOV3 cells were injected alone. e The weight of mice was recorded 3 times per week. Mice in the WEB2086 group had higher weights than did mice in the DMSO group (SKOV3 + MSC)