Fig. 7

Combined treatment with NVP-BEZ235 or MAPK inhibitors increases induction of apoptosis. a Nuclear fragmentation of MM cells treated with either/and 500 nM NVP-BEZ235, 25 µM Piceatannol and 0.5 ng bortezomib. Nuclear fragmentation was determined by the method of Nicoletti and analysed by flow cytometry. In comparison to Piceatannol alone, a combination with the common anti-myeloma agent bortezomib exerts no further increase of nuclear fragmentation. The addition of NVP-BEZ235 (an orally bioavailable dual phosphatidylinositol 3-kinase/mammalian target of rapamycin inhibitor) to Syk inhibitors increased nuclear fragmentation. Statistical analysis showed, that the combination of NVP-BEZ235 and Piceatannol is significantly higher than each drug alone. This works predominantly for AMO-1 cells. Calculational significant results in U266 cells can only be observed when correlated to Piceatannol, but not to NVP-BEZ235 (see Additional file 1). Results are expressed as the mean of three panels per pattern. Results are from one experiment representative of three. DMSO was used as control. The significance is related to DMSO. ⁺P<1.000, *P < 0.1, **P < 0.01, ***P < 0.001. b–e Effects of Syk inhibition in combination with MAP-Kinase inhibitors are demonstrated. MM cell lines were incubated with 5 µM Bay61-3606 in addition to varying concentrations of U0126 (b), SP600125 (c), PD98059 (d) or SB202190 (e) alone as well as in combination. Combined treatment of Bay61-3606 with U0126 (a potent, selective inhibitor of MAP2K), SP600125 (a selective inhibitor of JNK), or PD98059 (an inhibitor of MAP2K/MEK) and SB203580 (a selective inhibitor of p38 MAPK) results in significant synergistic or additive effects. Results are expressed as the mean of three panels per pattern. Results are from one experiment representative of three. DMSO was used for negative control. The significance is related to DMSO. ⁺P<1.000, *P < 0.1, **P < 0.01, ***P < 0.001.