Merck

Re-evaluation of cytostatic therapies for meningiomas in vitro.

Journal of cancer research and clinical oncology (2014-05-13)
Annette Wilisch-Neumann, Doreen Pachow, Maren Wallesch, Astrid Petermann, Frank D Böhmer, Elmar Kirches, Christian Mawrin
ABSTRACT

The purpose was to re-evaluate in cell culture models the therapeutic usefulness of some discussed chemotherapies or targeted therapies for meningiomas with a special emphasis on the role of the neurofibromatosis type 2 (NF2) tumor suppressor, which had been neglected so far. In addition, the study intended to evaluate a potential benefit from a treatment with drugs which are well established in other fields of medicine and have been linked recently with tumor disease by epidemiological studies. Meningioma cell lines corresponding to various subtypes and pairs of syngenic meningioma cell lines with or without shRNA-induced NF2 knockdown were analyzed for their dose-dependent response to the drugs in microtiter tetrazolium assays, BrdU assays and for selected cases in ELISAs measuring nucleosome liberation to specifically separate cell death from pure inhibition of cell proliferation. We confirmed a moderate efficacy of hydroxyurea (HU) in clinically relevant concentrations. Under appropriate dosing, we neither detected major responses to the alkylating compound temozolomide nor to various drugs targeting membrane receptors or enzymes (tamoxifen, erlotinib, mifepristone, losartan, metformin and verapamil). Only concentrations far beyond achievable serum levels generated significant effects with the exception of losartan, which showed no effects at all. Chemosensitivity varied markedly among meningioma cell lines. Importantly, cells with NF2 loss exhibited a significantly higher induction of cell death by HU. Alternative chemotherapeutic or targeted approaches besides HU have still to be evaluated in further studies, and the role of NF2 must be taken into account.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Tamoxifen citrate salt, ≥99%
Sigma-Aldrich
(±)-Verapamil hydrochloride, ≥99% (titration), powder
Supelco
Metformin hydrochloride, Pharmaceutical Secondary Standard; Certified Reference Material
Supelco
(±)-Verapamil hydrochloride, Pharmaceutical Secondary Standard; Certified Reference Material
Losartan potassium, European Pharmacopoeia (EP) Reference Standard
Sigma-Aldrich
1,1-Dimethylbiguanide hydrochloride, 97%
Supelco
Losartan potassium, analytical standard
Supelco
Verapamil hydrochloride solution, 1.0 mg/mL in methanol (as free base), ampule of 1 mL, certified reference material, Cerilliant®
Tamoxifen citrate for performance test, European Pharmacopoeia (EP) Reference Standard
Sigma-Aldrich
Mifepristone, ≥98%
Sigma-Aldrich
Hydroxyurea, 98%, powder
Sigma-Aldrich
Temozolomide, ≥98% (HPLC)
Supelco
Temozolomide, VETRANAL®, analytical standard
Sigma-Aldrich
Tamoxifen, ≥99%
Supelco
Tamoxifen, analytical standard
Verapamil hydrochloride, European Pharmacopoeia (EP) Reference Standard
Supelco
Temozolomide, Pharmaceutical Secondary Standard; Certified Reference Material
Tamoxifen citrate, European Pharmacopoeia (EP) Reference Standard
Supelco
Temozolomide, VETRANAL®, analytical standard