NHERF1/EBP50 as a Target for Modulation of MRP Function in HepG2 Cells

• Main Authors: Atsushi Kawase (Author), Miho Hirosoko (Author), Yuka Sugihara (Author), Yunosuke Koyama (Author), Ayaka Fukae (Author), Hiroaki Shimada (Author), Masahiro Iwaki (Author)
• Format: Book
• Published: MDPI AG, 2021-03-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

As increased expression and activities of efflux transporters (ETs) often cause drug resistance in cancers, we tried modulating ET activity in cancer cells, using scaffold proteins such as ezrin/radixin/moesin (ERM) proteins, and Na⁺/H⁺ exchanger regulatory factor-1 (NHERF1)/ERM-binding phosphoprotein of 50 kDa (<i>EBP50</i>). To see whether EBP50 modulated ET activities in human liver cancer HepG2 cells, we used <i>EBP50</i> siRNA and a designed TAT-PDZ1 peptide. The <i>EBP50</i> knockdown (<i>EBP50^KD</i>) cells had significantly higher intracellular accumulations of Rho123 and carboxy-dichlorofluorescein (CDF), but not H33342 (i.e., the respective substrates of P-glycoprotein (P-gp), multidrug resistance-associated protein (MRP), and breast cancer resistance protein (BCRP)), compared with control HepG2, suggesting that <i>EBP50</i> knockdown in HepG2 cells decreased activity of P-gp and MRP but not BCRP. Treatment with TAT-PDZ1 peptide (>1 pM) resulted in significantly higher CDF accumulation in HepG2 cells, which persisted for ≥180 min after TAT-PDZ1 peptide treatment. These results imply that EBP50 can modulate ET activities. To our knowledge, this is the first report on using a competitive peptide to modulate interactions between MRP and EBP50.

Item Description

10.3390/ph14030239
1424-8247