Targeting Voltage-Gated Potassium Channels in Breast Cancer: Mechanistic Insights into 4-Aminopyridine-Induced Cell Death

Cancer has recently been proposed as a type of channelopathy due to the aberrant expression of various ion channels. Voltage-gated potassium (K+) channels (VGKCs) are notably upregulated during tumor proliferation, while voltage-gated sodium (Na+) channels are predominantly associated with the invasive stage of cancer progression. Among these, the Kv10.1 channel has been found to be overexpressed in breast cancer, making it a promising therapeutic target. 4-Aminopyridine (4-AP), a non-selective voltage-gated potassium channel blocker, has emerged as a potential novel agent for breast cancer treatment. In this study, we aimed to elucidate the mechanism of action of 4-aminopyridine in breast cancer cells. To investigate the involvement of various cell death pathways, cycloheximide (CHX) (a paraptosis inhibitor), Z-VAD-FMK (a pan-caspase inhibitor), and 2-Aminoethoxydiphenyl borate (2-APB) (a phosphoinositide 3-kinase [PI3K] inhibitor) were employed. Experiments were conducted using the MCF-7 human breast cancer cell line and the L929 mouse fibroblast cell line as a healthy control. Assessments included cell viability assays, intracellular calcium (Ca2+) and K+ concentration measurements, and plasma membrane potential analysis. Our findings aim to contribute to the understanding of the therapeutic potential and cellular effects of VGKC blockers, particularly 4-aminopyridine, in breast cancer treatment strategies.