Kerr, I. D. | Search bioRxiv

bioRxiv2024

Tackling Anticancer Drug Resistance and Endosomal Escape in Aggressive Brain Tumors Using Bioelectronics

Chemotherapy resistance and endosomal entrapment, controlled by intracellular trafficking processes, are major factor in treatment failure. Here, we test the hypothesis that external electrical stimulus can be used to modulate intracellular trafficking of chemotherapeutic drugs in most common malignant brain tumors in childhood (medulloblastoma) and gold nanoparticles (GNPs) in adulthood (glioblastoma). We demonstrate that application of alternating current (AC) with frequencies ranging from KHz-MHz and low strength (1 V/cm) lead to killing of cisplatin and vincristine resistant (mediated by extracellular vesicles) medulloblastoma cell lines. On the other hand, in primary glioblastoma cells high frequency AC (MHz) regulated the endosomal escape of GNPs. No significant effect on the viability of the control medulloblastoma cells (resistant cells cultured in drug free media and non-resistant cells) and glioblastoma cells after AC treatment confirmed targeting of intracellular trafficking process. This work supports future application of AC in drug delivery and brain cancer therapy.

pharmacology and toxicology↗

bioRxiv2023

A time-resolved Forster resonance energy transfer assay to investigate inhibitor binding to ABCG2

The human ATP-binding cassette (ABC) transporter, ABCG2 is responsible for multidrug resistance in some tumours. Detailed knowledge of its activity is crucial for understanding drug transport and resistance in cancer, and has implications for wider pharmacokinetics. The binding of substrates and inhibitors is a key stage in the transport cycle of ABCG2. Here, we describe a novel binding assay using a high affinity fluorescent inhibitor based on Ko143 and time-resolved Forster resonance energy transfer (TR-FRET) to measure saturation binding to ABCG2. This binding is displaced by Ko143 and other known ABCG2 ligands, and is sensitive to the addition of AMP-PNP, a non-hydrolysable ATP analogue. This assay complements the arsenal of methods for determining drug:ABCG2 interactions and has the possibility of being adaptable for other multidrug pumps. HighlightsO_LIABCG2 is a multidrug pump which moves between states having low or high affinity for substrates and inhibitors C_LIO_LIWe introduce a time-resolved Forster resonance energy transfer assay to measure interaction of substrates and inhibitors to ABCG2 C_LIO_LIWe confirm that NBD dimerization is associated with a switch from a high to a low affinity site for an ABCG2 inhibitor C_LI

biochemistry↗