Fig. 5

Palbociclib treatment suppressed GBM tumorigenesis and M2 polarization. a Cell viability assay of palbociclib in TMZ-R and TMZ-S cells. Palbociclib exerted a potent inhibitory effect on cell viability in both TMZ-R and TMZ-S cells with estimated IC50 values of 1.0 μM and 0.5 μM respectively. Palbociclib treatment significantly reduced the colony (b) and neurosphere (c) forming ability in both TMZ-R and TMZ-S cells. d Real-time PCR analysis showed that lncSNHG15-silencing (upper panel) and palbociclib treatment (bottom panel) rendered TMZ-R cells incapable of promoting M2 polarization in macrophages. M1 markers, IFN-γ and TNF-α, were increased while M2 markers CD163 and CD206 were decreased. e Similarly, co-culturing TMZ-R cells with lncSNHG15-silenced (upper panel) or treated with palbociclib (bottom panel) decreased M2 cytokines (IL-6 and TGF-β) and increased M1 cytokines (IFN-γ and TNF-α) secreted by the GAMs