Anisomycin induces glioma cell death via down-regulation of PP2A catalytic subunit in vitro

Aim: To examine the effects of anisomycin on glioma cells and the related mechanisms in vitro. Methods: The U251 and U87 human glioblastoma cell lines were tested. The growth of the cells was analyzed using a CCK-8 cell viability assay. Apoptosis was detected using a flow cytometry assay. The expression of proteins and phosphorylated kinases was detected using Western blotting. Results: Treatment of U251 and U87 cells with anisomycin (0.01-8 mu mol/L) inhibited the cell growth in time-and concentration-dependent manners (the IC50 values at 48 h were 0.233+/-0.021 and 0.192+/-0.018 mu mol/L, respectively). Anisomycin (4 mu mol/L) caused 21.5%+/-2.2% and 25.3%+/-3.1% of apoptosis proportion, respectively, in U251 and U87 cells. In the two cell lines, anisomycin (4 mu mol/L) activated p38 MAPK and JNK, and inactivated ERK1/2. However, neither the p38 MAPK inhibitor SB203580 (10 mu mol/L) nor the JNK inhibitor SP600125 (10 mu mol/L) prevented anisomycin-induced cell death. On the other hand, anisomycin (4 mu mol/L) reduced the level of PP2A/C subunit (catalytic subunit) in a time-dependent manner in the two cell lines. Treatment of the two cell lines with the PP2A inhibitor okadaic acid (100 nmol/L) caused marked cell death. Conclusion: Anisomycin induces glioma cell death via down-regulation of PP2A catalytic subunit. The regulation of PP2A/C exression by anisomycin provides a clue to further study on its role in glioma therapy.