Fig. 4

MPPa-PDT activates RhoA via the mevalonate pathway, in turn driving YAP activation. a YAP expression and RhoA expression were highly positively correlated in OS samples (r = 0.667, P < 0.001). b, c Total RhoA and active RhoA (RhoA-GTP) expression in HOS and MG63 cells was assessed by the GTPase assay and western blotting at 12 h post-MPPa-PDT. d, e RhoA expression was assessed via qPCR in OS cells following RhoA lentivirus infection. f–i RhoA protein levels in OS cells following RhoA knockdown or overexpression were assessed via Western blotting. j–m Changes in RhoA protein levels following RhoA knockdown or overexpression were assessed via Western blotting. n, o HMGCR protein levels were assessed via Western blotting in HOS and MG63 cells at 12 h post-MPPa-PDT treatment. p, q HOS and MG63 cells were treated with mevalonate (200 mM) for 6 h, simvastatin (4 mM for HOS, 8 mM for MG63) for 24 h, or CCG-1423 (5 μm) for 48 h, after which protein expression was assessed via Western blotting. r, s HOS and MG63 cells were treated with mevalonate (200 mM) for 6 h, simvastatin (4 mM for HOS, 8 mM for MG63) for 24 h, or CCG-1423 (5 μm) for 48 h, after which a GTPase assay revealed changes in levels of active RhoA, with total RhoA serving as a normalization control. Experiments were repeated in triplicate. GAPDH served as a normalization control in all Western blotting assays unless otherwise noted. * P < 0.05 **P < 0.01 ***P < 0.001