MicroRNA-298 Reverses Multidrug Resistance to Antiepileptic Drugs by Suppressing MDR1/P-gp Expression in vitro.

Yangmei Xie,Xiaolin Deng,Yinghui Chen,Ming Wang,Yiye Shao

doi:10.3389/fnins.2018.00602

Abstract

P-glycoprotein (P-gp), a critical multidrug transporter, recognizes and transports various antiepileptic drugs (AEDs) through the blood-brain barrier (BBB). This may decrease the concentrations of AEDs in brain tissues and cause multidrug resistance (MDR) in patients with refractory epilepsy. Compelling evidence indicates that microRNAs (miRNAs) modulate MDR in various cancers by regulating P-gp expression. Furthermore, a previous study showed that miR-298 mediates MDR in breast cancer cells by downregulating P-gp expression. Based on the therapeutic results obtained from tumor cells, we aimed to determine whether miR-298 reverses MDR to AEDs by regulating P-gp expression in the BBB. We first established different drug-resistant cell lines, including PHT-resistant HBMECs (human brain microvascular endothelial cells) and doxorubicin (DOX)-resistant U87-MG (human malignant glioma) cells, by inducing P-gp overexpression. Quantitative real-time PCR (qRT-PCR) analysis revealed reduced expression of miR-298 in both HBMEC/PHT and U87-MG/DOX cells, and the luciferase reporter assay identified the direct binding of miR-298 to the 3′-untranslated region (3′-UTR) of P-gp. Moreover, ectopic expression of miR-298 downregulated P-gp expression at the mRNA and protein levels, thereby increasing the intracellular accumulation of AEDs in drug-resistant HBMEC/PHT and U87-MG/DOX cells. Thus, our findings suggest that miR-298 reverses MDR to AEDs by inhibiting P-gp expression, suggesting a potential target for overcoming MDR in refractory epilepsy.

Highlights

Epilepsy is one of the most common neurological disorders, affecting approximately 50 million people worldwide (Henshall et al, 2016)
Epidemiological data indicate that approximately 30% of patients with epilepsy exhibit a poor response to a variety of antiepileptic drugs (AEDs), these drugs differ in their pharmacodynamics, pharmacological mechanisms and interaction potential
Overexpression of ATP-binding cassette (ABC) efflux transporters in the blood-brain barrier (BBB) contributes to multidrug resistance (MDR) in various central nervous system (CNS) diseases (Miller, 2015)

Summary

Introduction

Epilepsy is one of the most common neurological disorders, affecting approximately 50 million people worldwide (Henshall et al, 2016). Epilepsy is mainly treated with antiepileptic drugs (AEDs). Epidemiological data indicate that approximately 30% of patients with epilepsy exhibit a poor response to a variety of AEDs, these drugs differ in their pharmacodynamics, pharmacological mechanisms and interaction potential. Patients exhibiting multidrug resistance (MDR) subsequently develop refractory epilepsy (Kwan and Brodie, 2000; Kwan et al, 2010) and suffer from severe psychosocial problems, intellectual dysfunction, a reduced quality of life, and even increased morbidity and mortality (French, 2007). In the past few decades, MicroRNA-298 Reverses MDR to AEDs several mechanisms of refractory epilepsy have been proposed, including the pharmacokinetic hypothesis, the neural network hypothesis, the seizure severity hypothesis, the gene variant hypothesis, and the transporter hypothesis (Tang et al, 2017). The transporter hypothesis is the most widely accepted and investigated theory (Potschka, 2012)

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