In vitro activity: Midostaurin(pkc412) is a broad spectrum protein kinase inhibitor. Midostaurin(pkc412) interacts strongly with ATP binding sites of the conventional PKC-α, -β and -γ, PDGFRβ, VEGF-R2, VEGF-R1 and the cyclin-dependant kinase 1-cyclin B complex. Midostaurin(pkc412) inhibits the growth of various human and animal cell lines in vitro at similar submicromolar concentrations. Midostaurin(pkc412) also effectively inhibits the in vitro proliferation of glioblastoma and induced the accumulation of cells in G2/M and formation of giant nuclei with extensive fragmentation and apoptotic bodies. Midostaurin(pkc412) is able to reverse the p-glycoprotein-mediated multidrug resistance of tumor cells in vitro.

Kinase Assay: PKC412 is a multi-targeted protein kinase inhibitor which inhibits PKCα/β/γ, Syk, Flk-1, Akt, PKA, c-Kit, c-Fgr, c-Src, FLT3, PDFRβ and VEGFR1/2 with IC50 ranging from 16-500 nM.

Cell Assay: Midostaurin shows reversible inhibition of intracellular PKC activity with IC50 value of 0.5μM. Besides PKC, midostaurin inhibits the autophosphorylation of the receptors for PDGF, VEGF and stem cell factor with IC50 values of 80nM, 1μM and 30nM, respectively. Midostaurin also inhibits the FGF-induced c-fos transcription and MAPK activation. Moreover, midostaurin suppresses cell growth of different cell lines through inducing cell cycle arrest in G2/M and inducing apoptosis. Proliferation is determined by trypan blue dye exclusion test. Cells in suspension are seeded in six-well plates at a density of 1×105 cells/mL in the presence of different concentrations of PKC412 for 3 days. In control wells, DMSO instead of PKC412 is added. After the treatment, 10 μL of the cell suspension is mixed with 10 μL of 0.4% trypan blue, and alive cells are counted manually using a hemacytometer. Results are calculated as the percentage of the values measured when cells are grown in the absence of the reagent. All experiments are performed in triplicate.