Fig. 2

PP2A is inhibited in MM and FTY720 reactivates it. a Quantification of PP2A activity in indicated MM and HM cells was performed using a PP2A-specific enzymatic activity assay. Results are expressed as percentage of PP2A activity, as compared to PP2A activity detected in HM cells. Mean and SD of 3 replicates of a representative experiment, out of three performed, are given. b Representative western blot analysis of PP2A, SET and CIP2A protein levels in 6 human MM cell lines and 3 HM cultures. Levels of α-tubulin were detected as loading control. c Quantification of PP2A activity in indicated MM cells 24 h after treatment with 6 µM FTY720 or vehicle. Results are expressed as percentage of PP2A activity normalized to vehicle control, for each cell line separately. Means and SD of 3 replicates of a representative experiment, out of three performed, are given. d PP2A was immunoprecipitated from MILL and PHI cell cultures untreated or treated with FTY720 (6 µM) or vehicle for 8 and 24 h. Immunoprecipitates were probed with anti-SET antibody (upper panel) and anti-PP2A antibody, as loading control (lower panel). Relative densitometric analysis data, for SET protein levels, normalized to PP2A protein levels, are shown