The voltage-gated proton channel HV1 is responsible for the passive efflux of protons. It contributes to pH homeostasis in neurons, phagocytes, muscle and epithelial cells and to the regulation of the production of reactive oxygen species in phagocytes. The voltage-gated proton channel HV1 can be overexpressed in certain cancers such as breast cancer, colon cancer and B-cell leukemia. Selective inhibition of the proton channel has an antiproliferative effect on cancer cells and slows down their metastasis. Several proton channel HV1 inhibitors have already been discovered, but none of them has been approved for use in medicine.
In this Master’s thesis we have prepared proton channel HV1 inhibitors with a 2-aminoimidazole scaffold. The compounds are analogues of NZ-49, a compound previously prepared by researchers from the Department of Pharmaceutical Chemistry at the Faculty of Pharmacy, University of Ljubljana. We have prepared four final compounds with 2-aminoimidazole scaffold and 1,3-, 1,4-, 1,3,4- substituted benzyl fragment. The 2-aminoimidazole fragment remained unchanged as its importance for channel inhibition was proven previously. We investigated the identity and purity of the final compounds using nuclear magnetic resonance (NMR), high resolution mass spectrometry (HRMS) and ultra high performance liquid chromatography (UHPLC). The prepared final compounds were tested biologically using the electrophysical patch-clamp method on CHO cells expressing human HV1. The results were calculated as remaining current fraction (RCF). All tested compounds showed an inhibitory effect with RCF values between 0.15 and 0.26. Compound 14 with a 1,3-substituted benzyl ring with a trifluoromethyl group in the meta position showed the most potent inhibitory activity (RCF = 0.15). A dose-response experiment was performed for compound 14, which confirmed the concentration-dependent inhibition of the HV1 channel. The final results are promising for the further development of HV1 inhibitors with 2-aminoimidazole scaffold.
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