Cyanine 5-huwentoxin-IV as a novel imaging probe to detect hNav1.7 channel overexpressed in non-small cell lung cancer

Currently, tools for detecting cancer cells belonging to the non-small cell lung cancer (NSCLC) are lacking. As overexpression of human voltage-gated sodium channel subtype 1.7 (hNa_v1.7) channels was identified as a promising marker in NSCLC, we investigated whether huwentoxin-IV (HwTx-IV), known to interact preferentially with this sodium channel subtype at nanomolar concentrations, may serve as a practical tool for detecting NSCLC. To achieve this goal, we coupled HwTx-IV to the cyanine 5 fluorophore and evaluated the potential of cyanine 5-HwTx-IV (Cy5-HwTx-IV) as an imaging agent to improve the detection of this cancer type. Increased messager ribonucleic acid (mRNA) expression levels of hNa_v1.7 were confirmed in the A549 and H460 NSCLC cell lines, but not in the Beas-2B healthy lung cell line. Moreover, electrophysiological recordings validated the presence of functional hNa_v1.7 in the metastatic H460 cell line, the recorded Na⁺ current in this cell line being completely abolished in the presence of nanomolar concentrations of Cy5-HwTx-IV and HwTx-IV. In contrast, functional hNa_v1.7 was not detected in the non-metastatic A549 and healthy lung Beas-2B cell lines. Finally, confocal laser scanning microscopy allowed localisation of hNa_v1.7 at the plasma membranes of cells labelled with Cy5-HwTx-IV. In conclusion, this work establishes Cy5-HwTx-IV as a promising tool for NSCLC imaging, thereby enhancing diagnostic precision for this cancer type.