Cutaneous T-Cell Lymphoma (CTCL) Cell Line-Derived Extracellular Vesicles Contain HERV-W-Encoded Fusogenic Syncytin-1

Non peer reviewe

Cellular analysis of the action of epigenetics drugs and probes

Small molecule drugs and probes are important tools in drug discovery, pharmacology, and cell biology. This is of course also true for epigenetic inhibitors. Important examples for the use of established epigenetic inhibitors are the study of the mechanistic role of a certain target in a cellular setting or the modulation of a certain phenotype in an approach that aims towards therapeutic application. Alternatively, cellular testing may aim at the validation of a new epigenetic inhibitor in drug discovery approaches. Cellular and eventually animal models provide powerful tools for these different approaches but certain caveats have to be recognized and taken into account. This involves both the selectivity of the pharmacological tool as well as the specificity and the robustness of the cellular system. In this article, we present an overview of different methods that are used to profile and screen for epigenetic agents and comment on their limitations. We describe not only diverse successful case studies of screening approaches using different assay formats, but also some problematic cases, critically discussing selected applications of these systems

Nitroreductase-Mediated Release of Inhibitors of Lysine-Specific Demethylase 1 (LSD1) from Prodrugs in Transfected Acute Myeloid Leukaemia Cells

Lysine-specific demethylase 1 (LSD1) has evolved as a promising therapeutic target for cancer treatment, especially in acute myeloid leukaemia (AML). To approach the challenge of site-specific LSD1 inhibition, we developed an enzyme-prodrug system with the bacterial nitroreductase NfsB (NTR) that was expressed in the virally transfected AML cell line THP1-NTR+. The cellular activity of the NTR was proven with a new luminescent NTR probe. We synthesised a diverse set of nitroaromatic prodrugs that by design do not affect LSD1 and are reduced by the NTR to release an active LSD1 inhibitor. The 2-nitroimidazolyl prodrug (1f) of a potent LSD1 inhibitor emerged as one of the best prodrug candidates with a pronounced selectivity window between wild-type and transfected NTR+ cells. Our prodrugs are selectively activated and release the LSD1 inhibitor locally in turn blocking colony formation. This system may be applied in future targeting approaches to reach tissue- or organ-type-specific inhibition of LSD1.<br /

Soft drug-inhibitors for the epigenetic targets Lysine-Specific Demethylase 1 (LSD1) and Histone Deacetylases (HDACs)

Epigenetic modulators such as Lysine-specific Demethylase 1 (LSD1) and Histone Deacetylases (HDACs), are drug targets for cancer, neuropsychiatric disease or inflammation but inhibitors of these enzymes exhibit considerable side effects. For a potential local treatment with reduced systemic toxicity, we present here soft drug candidates as new LSD1 and HDAC inhibitors. A soft drug is a compound that is degraded in vivo to less active metabolites, after having achieved its therapeutic function. This has been successfully applied for corticosteroids in the clinic but soft drugs targeting epigenetic enzymes are scarce, with the HDAC inhibitor remetinostat being the only example. We have developed new methyl ester containing inhibitors targeting LSD1 respectively HDACs and compared the biological activity of these to their respective carboxylic acids cleavage products. In vitro activity assays, cellular experiments, and a stability assay identified potent HDAC and LSD1 soft drug candidates that are superior to their corresponding carboxylic acids in cellular models