Abstract
Resistance mechanisms in brain tumors, such as medulloblastoma and glioblastoma, frequently involve the entrapment of chemotherapeutic agents within endosomes and the extracellular expulsion of drugs. These barriers to effective treatment are exacerbated in nanotechnology-based drug delivery systems, where therapeutic nanoparticles often remain confined within endosomes, thus diminishing their therapeutic efficacy. Addressing this challenge necessitates the development of novel strategies to enhance the efficiency of cancer therapies. This study tests the hypothesis that external electrical stimuli can modulate intracellular trafficking of chemotherapeutic drugs in common malignant brain tumors in children (medulloblastoma) and adults (glioblastoma) by using gold nanoparticles (GNPs). In our experiments, alternating current (AC) stimulation ranging from 1 kHz to 5 MHz and at a strength of 1 V/cm significantly reduced cell viability in drug-resistant medulloblastoma and enhanced delivery of GNPs in glioblastoma. Low-frequency AC resulted in a 50% increase in apoptosis compared to controls and an 8-fold increase in cell death in cisplatin-resistant medulloblastoma cells, accompanied by a substantial reduction in EC50 from 2.5 to 0.3 μM. Similarly, vincristine-resistant cells demonstrated a 4-fold enhancement in drug sensitivity. Furthermore, high-frequency AC facilitated a significant increase from 20 to 75% in the endosomal escape of GNPs in glioblastoma cells. These findings underscore the potential of AC to selectively disrupt cancer cell resistance mechanisms and bolster the efficacy of nanoparticle-based therapies. The results indicate the effectiveness of AC stimulation in circumventing the limitations inherent in current nanotechnology-based drug delivery systems but also illustrates its transformative potential for treating aggressive, drug-resistant brain tumors.