Fig. 6.

DKK3 promotes aggressive behaviours in CAFs via YAP/TAZ. a Western blots showing β-catenin, YAP, TAZ, pY416-Src (pSRC), pS19-MLC2 (pMLC2) and Tubulin in CAF1 following transfection with control (siCtr), β-catenin (siβcat; smart-pool) or YAP/TAZ (siY/T; smart-pool) siRNAs. b Tukey boxplot shows gel contraction of CAF1 transfected as in (a); n = 8 gels except for siY/T that n = 6. c Tukey boxplot shows invasion index (3D invasion) measured from TS1 spheroids obtained after 3D co-culture with CAF1 transfected as in (a); n > 32 individual spheroids out of 3 independent experiments. d Representative images of end-point TS1 (red) MOT co-culture with CAF1 transfected as in (a). Scale bar, 100 µm. Graph shows the area of colonies. Bars represent mean ± SEM (n = 570 or more colonies from at least 3 independent experiments). e Tukey boxplot shows gel contraction index of CAF-WT or CAF-KO.9 stably expressing empty vector (empty) or constitutive active YAP mutant (YAP^S5A); n = 7 gels or more. f Representative images of end-point TS1 (red) MOT co-culture with CAF-KO.9 stably expressing empty vector (empty) or YAP^S5A. Scale bar, 100 µm. Tukey boxplot shows the area of colonies; n = 28 or more colonies from at least 3 independent experiments. g Western blot showing levels of pY416-Src (pSRC), pS19-MLC2 (pMLC2) and Gapdh in CAF-WT or CAF-KO.9 stably expressing empty vector (KO.9), DKK3 (KO.9-REC), or YAP^S5A. h Schematic diagram showing the model integrating our findings. HSF1 in CAFs upregulates DKK3 which in turn potentiates YAP/TAZ and β-catenin signalling. YAP promotes actomyosin contractility leading to ECM remodelling and cancer cell growth and invasion. The role of β-catenin is still undetermined. i Western blots show Hsf1, non-phospho (active) β-catenin (Ser33/37/Thr41), β-catenin, YAP, TAZ, pS19-MLC2 (pMLC2) and Tubulin in murine CAF1 and CAF5 after transfection with control (siCtr) or Hsf1 (smart-pool) siRNAs. j Graph shows gel contraction of CAF-WT, CAF-KO.9-REC and CAF-KO.9-YAP^S5A after transfection with control (siCtr) or Hsf1 (smart-pool) siRNAs. Bars represent mean ± SEM (n = 3 or more). A dashed red line indicates the average contraction by KO.9 CAFs. For all graphs, *P < 0.05; **P < 0.01; ***P < 0.001; #P < 0.0001; n.s., non-significant