The voltage-gated potassium channel KV1.3 is a transmembrane protein involved in numerous physiological functions and pathological conditions, including cancer progression. Therefore, it represents an important target for the development of anticancer therapies, as increased expression of KV1.3 has been observed in the majority of tumor types.
While plasma membrane KV1.3 channels are involved in cell proliferation, mitochondrial KV1.3 channels play a crucial role in the process of apoptosis. By synthesizing mitochondrial KV1.3 inhibitors we aim to selectively deliver the compounds into mitochondria, where they
will influence apoptotic pathways and consequently inhibit cancer progression.
In the master’s thesis we designed and synthesized new mitochondrial KV1.3 inhibitors based on the structure of the known KV1.3 inhibitor TVS-26. The core benzamide scaffold
was maintained and chemically modified to enable targeted delivery of the compound to the mitochondria. The synthesis involved multiple steps: firstly, we synthesized the benzamide scaffold and then attached linkers of various lengths with different functional groups. In the
final step, we attached a transport moiety, which is essential for the mitochondrial delivery
of the entire conjugate. Five final compounds were synthesized and their identity and purity were confirmed using nuclear magnetic resonance (NMR) spectroscopy, high-resolution mass spectrometry (HRMS), and high-performance liquid chromatography (HPLC).
The final compounds were biologically evaluated in the MCF-7 breast cancer cell line. All five final compounds exhibited cytotoxic activity. Among them, compounds 17 and 26, with
a tris(4-methoxyphenyl)phosphonium cation and linkers of different lengths, demonstrated the highest potency. Compound 26 showed the strongest activity, with an inhibitory concentration of 2.0 ± 0.8 μM, which may be attributed to the presence of the long, heptyl
linker. Compounds 16 and 25 displayed comparable, although slightly lower cytotoxic activity, whereas compound 8 was the least active. From these results we can conclude that
the appropriate lipophilicity contributes to the cytotoxic activity, because it facilitates the passage of the compound to the mitochondria, while the presence of a permanent cation enables its accumulation in the mitochondria. Based on the results obtained from biological evaluation in the MCF-7 cancer cell line, it would be reasonable to evaluate these compounds in additional cancer as well as in non-cancerous cell lines. The final results are promising
for the further development of mitochondrial KV1.3 inhibitors.
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