Figure 4

Inhibition of PP2A is essential for CIP2A-induced proliferation and Dex therapy. (a) MM.1R or U266 cells were transfected with a CIP2A siRNA, and PP2A activity was measured by PP2A phosphatase assay 48 h after transfection. (b) MM.1R or U266 cells were transfected with 100 nM CIP2A or negative control (NC) siRNA, and total protein was isolated 48 h after transfection and then subjected to western blot analysis. (c) MM.1R cells were transfected with CIP2A siRNA alone or in combination with 10 nM okadaic acid (OA) for 12, 24 and 48 h; cell viability was evaluated using a hemoatocytometer. (d) MM.1R cells were transfected with 100 nM CIP2A. And, 48 h after transfection, the cells were treated with Dex (3 μM) and/or OA (10 nM), and then subjected to CCK-8 to detect the proliferation. (e, f) MM.1R or U266 cells were transfected with CIP2A siRNA alone or in combination with 10 nM OA for 48 h. Whole-cell extracts were prepared and examined by western blot using indicated antibodies. *P<0.05, **P<0.01.