Repurposing T-type calcium channel blocker lomerizine as a therapeutic strategy for glioblastoma
Toshiya Ichinose, Sho Tamai, Nozomi Hirai, Takashi Maejima, Kosuke Nambu, Hemragul Sabit, Shingo Tanaka, Masashi Kinoshita, Masahiko Kobayashi, Michihiro Mieda, Atsushi Hirao, Mitsutoshi Nakada
Toshiya Ichinose, Sho Tamai, Nozomi Hirai, Takashi Maejima, Kosuke Nambu, Hemragul Sabit, Shingo Tanaka, Masashi Kinoshita, Masahiko Kobayashi, Michihiro Mieda, Atsushi Hirao, Mitsutoshi Nakada
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Research Article Cell biology Oncology

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

Abstract

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.

Authors

Toshiya Ichinose, Sho Tamai, Nozomi Hirai, Takashi Maejima, Kosuke Nambu, Hemragul Sabit, Shingo Tanaka, Masashi Kinoshita, Masahiko Kobayashi, Michihiro Mieda, Atsushi Hirao, Mitsutoshi Nakada

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Figure 2

Lomerizine treatment induces apoptosis in glioma cell lines.

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Lomerizine treatment induces apoptosis in glioma cell lines. The effect ...
The effect of lomerizine on the induction of apoptosis was evaluated using immunofluorescence, annexin V assays, and Western blotting in vitro. (A) Representative images of nuclear staining of KGS01 with or without lomerizine treatment for 24 hours, using Hoechst 33258 (blue) and propidium iodide (PI) (red). Apoptotic cells are indicated as condensed chromatin, with both Hoechst 33258– and PI-positive cells (pink). Inset shows higher magnification image (5×) of double-stained apoptotic cells. Bar graphs revealing the average number of double-stained apoptotic cells per high-power field for all GICs (KGS01, KGS10, and KGS15) and their differentiated cell lines (DKGS01, DKGS10, and DKGS15). (B) All GICs (KGS01, KGS10, and KGS15) and their differentiated cell lines (DKGS01, DKGS10, and DKGS15) were incubated with DMSO or lomerizine (1 μM or 5 μM) for 24 hours and then analyzed for apoptosis using annexin V/PI staining assays. Representative flow cytometry dot plots of apoptosis. The graphs represent the percentages of total apoptotic cells, including both the early and late apoptotic cells after treatment with different concentrations of lomerizine. Data are presented as the mean ± SEM of triplicate experiments. (C) Western blot analysis revealing the expression of cleaved PARP and PARP in all GICs and their differentiated cell lines treated with lomerizine for 24 hours. β-Actin was used as a loading control. Scale bars: 100 μm (A). Bars represent mean values ± SD (A and B). Data were analyzed by 1-way ANOVA with Tukey’s multiple-comparison test. *P < 0.05, **P < 0.01, ***P < 0.005 vs. DMSO.