Cancer is a major public health concern and, along with cardiovascular diseases, remains the leading cause of death in the developed world. In order to discover a therapeutic strategy that would target a broad spectrum of cancer diseases, scientists have focused on the acidic tumor microenvironment, a hallmark of cancer cells. The voltage-gated proton channel HV1 plays a key role in regulation of intracellular pH. Since changes in pH balance are closely related to cancer development and metastasis, the HV1 channel presents a promising anticancer therapeutic target, as well as a potential predictor of cancer incidence and prognosis. Voltage-gated proton channels are ion channels highly selective for protons, located in the cell membrane. Two major types of inhibitors of these channels have been identified, zinc ions and guanidine derivatives.
The aim of this master's thesis was to synthesize and evaluate new inhibitors of the HV1 channel with a 5-phenyl-2-aminoimidazole scaffold. When designing new inhibitors, we focused on the optimization of the compounds NZ-49 and GHK-21, which were discovered at the Department of Pharmaceutical Chemistry of the Faculty of Pharmacy. Six new potential inhibitors of the voltage-gated proton channel HV1 were synthesized according to the established four-step synthetic procedure. For the synthesis, we selected those compounds that best complemented the structure-activity relationship of previously synthesized compounds from this structural class. The identity and purity of the synthesized compounds were evaluated using nuclear magnetic resonance spectroscopy, infrared spectroscopy, mass spectrometry and high-resolution liquid chromatography. We determined the biological effects of the prepared inhibitors. For this, we used the electrophysiological patch-clamp method on CHO cells expressing the voltage-gated proton channel HV1. The efficiency of the inhibitors was expressed as a proportion of the remaining current fraction through the channel. All five biologically tested compounds were effective at a concentration of 50 µM, as they reduced the flow of protons through the HV1 channel by 48 to 80 %. Compound 19 with a benzyloxy substituent at the para position proved to be the most potent inhibitor. It reduced the flow of protons by 80 % and thus more strongly than compound NZ-49, which served as our starting compound. The biological effectiveness of the other four compounds was slightly weaker, as they inhibited the proton flux by 48-61 %.
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