Fig. 5

MTX and DOX decrease mammalian sterile 20-like kinase 1 (MST1) expression by altering its protein stability. a Western blotting representative image of mammalian sterile 20-like kinase 1 (MST1) total protein level in MTX- or DOX-treated osteosarcoma cells. MST1 protein level was decreased by MTX and DOX. b The MST1 mRNA levels in the control and MTX- or DOX-treated osteosarcoma cells were monitored via real-time polymerase chain reaction using specific primers. The error bars represent mean ± SD. Compared with control (t test, n = 3), **P < 0.01. MST1 mRNA did not decrease after MTX or DOX treatments. c U2OS cells were treated with 100 μg/mL of cycloheximide for the indicated periods. The endogenous MST1 protein levels were determined by western blotting (upper panels), and relative MST1 protein levels were normalized to those of GAPDH (lower panels). The error bars represent mean ± SD. Compared with control (paired t test, n = 3), **P < 0.01.MST1 degradation was increased by MTX and DOX in U2OS cells. CHX cycloheximide