Clemastine suppresses proneural glioblastoma stem cell growth

Glioblastoma (GBM) cells’ stemness-like features and lineage plasticity promote tumor progression. Here, we demonstrate that Clemastine, a drug for treating hay fever and allergy symptoms, effectively attenuated the stemness and suppressed the propagation of primary GBM cultures bearing PDGFRA amplification. We show that these effects of GBM cells were accompanied by altered gene expression profiling indicative of a more differentiated state of tumor cells, in resonating with Clemastine’s activity in promoting the differentiation of normal oligodendrocyte progenitors (OPCs) into mature oligodendrocyte. Functional assays for proteins that can be pharmacologically targeted by Clemastine, including histamine receptors, muscarinic receptors, and Emopamil binding protein (EBP), revealed the essential roles of these proteins in sustaining GBM cell propagation and suggested that Clemastine likely impairs tumor cells via targeting multiple pathways. Finally, we showed that a PDGFB-driven mouse glioma model, representing the proneural subtype GBMs, was similarly susceptible to Clemastine treatment. Collectively, these results identify pathways that are essential for maintaining the proneural progenitor features of GBMs, and suggest that non-oncology, low toxicity drugs with OPC differentiation promoting effects, such as Clemastine, can be exploited for targeting GBM cell’s progenitor property. a mouse GBM cell line was treated with vehcle control or clemastine or cw3388