Fig. 4

Deletion of Pdgfrβ in Brca1-deficient tumor cells promotes cell death, induces MET, and suppresses tumorigenesis. a Primary p18^−/−;Brca1^MGKO tumor cells were transfected with Pdgfrβ CRISPR/Cas9 KO plasmids. Forty-eight hours later, GFP^neg and GFP^pos cells were sorted out and analyzed by western blot. b p18^−/−;Brca1^MGKO cells were transfected with Pdgfrβ CRISPR/Cas9 KO plasmids. After 48 h, annexin V-positive rate in Pdgfrβ WT (GFP^neg) and Pdgfrβ KO (GFP^pos) cells was determined by flow cytometry. c–e Primary p18^−/−;Brca1^MGKO tumor cells were transfected with Pdgfrβ CRISPR/Cas9 KO plasmids. Forty-eight hours later, FACS-sorted Pdgfrβ WT (GFP^neg) and Pdgfrβ KO (GFP^pos) cells were cultured and monitored for additional 7 days (c). The number of viable cells at day 5 and day 7 was counted (d), and the percentage of dead cells at day 7 were calculated (e). The asterisk (*) denotes a significance from Pdgfrβ WT and Pdgfrβ KO cells at day 5 or day 7. f Freshly sorted Pdgfrβ WT and KO p18^−/−;Brca1^MGKO tumor cells that were viable were transplanted into MFP of NSG mice. Four weeks later, regenerated tumor volumes were determined. Data are represented as mean ± SD of three tumors in each group. g, h Tumors generated from f were analyzed by western blot (g) and IHC (h). PS, ponceau staining. The insets show the enlarged cells that are representative. E-cad-positive cells are indicated by arrowheads