Repurposing T-type calcium channel blocker lomerizine as a therapeutic strategy for glioblastoma.

Glioblastoma (GBM) is the most malignant primary brain tumor. The presence of glioma stem/initiating cells (GICs) is known to cause strong treatment resistance; therefore, GICs are a major target for GBM therapy, although there are no therapies targeting GICs clinically. To identify novel treatments for GBMs, we performed drug repurposing screening using GICs and identified the T-type calcium channel blocker lomerizine - a migraine prophylactic drug. Lomerizine inhibited proliferation, migration, invasion, and cell cycle progression and induced apoptosis in GICs and differentiated glioma cells. Lomerizine had antitumor effects by inactivating STAT3 in all cell lines. Furthermore, lomerizine also dephosphorylated AKT and ERK only in GICs and had strong tumor-suppressive ability. Lomerizine also reduced tumor volume and prolonged overall survival in vivo. Based on our data from in vitro and in vivo experiments, lomerizine has potential as a GBM therapeutic agent targeting both GICs and differentiated glioma cells and could benefit GBM patients.