gms | German Medical Science

Objective: Treatment of aggressive meningiomas is still challenging for a couple of reasons, including

1.

high rate of recurrence of higher-grade meningiomas,

2.

impossible total resection and

3.

a lack of effective chemotherapies.

To address this urgent need for more successful treatments of aggressive meningiomas, we tested 147 FDA-approved antineoplastic drugs on two different meningioma cell lines Ben-Men-1 (WHO°I) and NCH93 (WHO°III).

Methods: Cell proliferation was assessed by crystal violet assay or manual counting. The wound healing assay was performed with IC50 values of each drug. Pictures were taken at 0 and 12h after treatment. For colony formation assay, the cells were treated for 48h with IC50 values and thereafter, drugs were washed off and the cells were seeded into a 10 cm dish. After an incubation period of 10d, colonies were then stained with crystal violet and manually counted. For flow cytometry, cells were treated with 10xIC50 and stained with PI and annexin V after 24 and 48h, respectively.

Results: The impact of FDA-approved drugs on tumor cell proliferation was assessed in a high-throughput 386-well format and revealed Bortezomib (BTZ), Carfilzomib (CFZ), Omacetaxine (HHT), Paclitaxel (PTX) and Ponatinib (POT) as the top 5 most effective drugs. Dose-curve analysis revealed IC50 values of these drugs in Ben-Men-1 and NCH93 cell lines in the nM and lower µM range as follows: BTZ 16.2 and 5.7 nM, CFZ 4.8 and 2.6 nM, HHT 5.0 and 8.9 nM, PTX 2.6 and 1.9 µM, and POT 278 and 206 nM, respectively. Drug concentrations of IC50 and 10xIC50 values lead to an average inhibition of proliferation of both cell lines by up to 90% after 48h (P<.001). Furthermore, migration was reduced with all tested drugs by up to 60% after 12h (P<.05). Additionally, BTZ, CFZ and PTX significantly impaired the formation of colonies in both cell lines (P<.001). The impact of the drugs on cell cycle and apoptosis was analyzed by flow cytometry. Especially BTZ, CFZ and PTX resulted in a G2/M arrest of treated cells (P<.001) and subsequently, all drugs induced apoptosis after 48h, whereof BTZ led to the most pronounced effect by up to 80% apoptotic cells (P<.001).

Conclusion: In conclusion, we identified five potent drugs for the treatment of aggressive meningiomas by applying a high-throughput drug screening of 147 FDA-approved antineoplastic drugs. Functional testing revealed profound effects of all tested drugs on proliferation, migration, cell cycle, colony formation and on the induction of apoptosis.