Ex vivo therapy of malignant melanomas transplanted into organotypic brain slice cultures using inhibitors of histone deacetylases
Disease progression in patients suffering from malignant melanomas is often determined by metastatic spreading into brain parenchyma. Systemic chemotherapy regimens are, therefore, mandatory for successful treatment. Most recently, inhibitors of histone deacetylases (HDACi) have been shown to significantly inhibit melanoma progression. Here, mouse as well as human melanoma cells were transplanted into rodent hippocampal slice cultures in order to translate and microscopically confirm promising in vitro chemotherapeutic propensities of HDACi within the organotypic brain environment. In our ex vivo model, tumor progression was significantly inhibited by administration of low micromolar concentrations of second generation HDACi MS-275 over a period of 8 days. In contrast, HDACi treatment with suberoylanilide hydroxamic acid was less efficient ex vivo, although both compounds were successful in the treatment of tumor cell monolayer cultures. Protein levels of the cell cycle inhibitor p21WAF1 were significantly increased after HDACi treatment, which points to enhanced G1 arrest of tumor cells as confirmed by cytofluorometric analysis. Considering the ability of MS-275 to cross the blood–brain barrier, our experimental model identifies the benzamide MS-275 as a promising therapeutic compound for targeting epigenetic chromatin modulation as systemic treatment of metastatic melanomas.
KeywordsMS-275 Valproic acid SAHA M344 Hippocampus p21 Melanoma metastases
We kindly acknowledge Dr P. Rohwer, Nikolaus-Fiebiger-Center of Molecular Medicine, University of Erlangen-Nuremberg for assistance with fluorescence tumor cell sorting. We thank Tajana Jungbauer, Ina Jeske, Silke Gutmann and Birte Rings for technical support.
- 13.Fournel M, Trachy-Bourget MC, Yan PT, Kalita A, Bonfils C, Beaulieu C, Frechette S, Leit S, Abou-Khalil E, Woo SH, Delorme D, MacLeod AR, Besterman JM, Li Z (2002) Sulfonamide anilides, a novel class of histone deacetylase inhibitors, are antiproliferative against human tumors. Cancer Res 62:4325–4330PubMedGoogle Scholar
- 21.Hockly E, Richon VM, Woodman B, Smith DL, Zhou X, Rosa E, Sathasivam K, Ghazi-Noori S, Mahal A, Lowden PA, Steffan JS, Marsh JL, Thompson LM, Lewis CM, Marks PA, Bates GP (2003) Suberoylanilide hydroxamic acid, a histone deacetylase inhibitor, ameliorates motor deficits in a mouse model of Huntington’s disease. Proc Natl Acad Sci USA 100:2041–2046PubMedCrossRefGoogle Scholar
- 22.Hu E, Dul E, Sung CM, Chen Z, Kirkpatrick R, Zhang GF, Johanson K, Liu R, Lago A, Hofmann G, Macarron R, de los Frailes M, Perez P, Krawiec J, Winkler J, Jaye M (2003) Identification of novel isoform-selective inhibitors within class I histone deacetylases. J Pharmacol Exp Ther 307:720–728PubMedCrossRefGoogle Scholar
- 43.Sambrook J, Russell DW (2001) Molecular cloning. In: Introducing cloned genes into cultured mammalian cells. CSHL Press, Cold Spring HarbourGoogle Scholar
- 45.Stein TD, Anders NJ, DeCarli C, Chan SL, Mattson MP, Johnson JA (2004) Neutralization of transthyretin reverses the neuroprotective effects of secreted amyloid precursor protein (APP) in APPSW mice resulting in tau phosphorylation and loss of hippocampal neurons: support for the amyloid hypothesis. J Neurosci 24:7707–7717PubMedCrossRefGoogle Scholar
- 48.Wisinski KB (2003) A phase I study of an oral histone deacetylase inhibitor, MS-275 in patients with refractory solid tumors and lymphomas. Proc Am Soc Clin Oncol 22:802Google Scholar