Phytoestrogens Modulate Breast Cancer Resistance Protein Expression and Function at the Blood-Cerebrospinal Fluid Barrier

Authors

  • Manjit Kaur Aston University, School of Life and Health Sciences, Aston Triangle, Birmingham
  • Raj Kumar Singh Badhan Aston University, School of Life and Health Sciences, Aston Triangle, Birmingham http://orcid.org/0000-0002-0904-9324

DOI:

https://doi.org/10.18433/J3P31K

Abstract

PURPOSE: Breast cancer resistance protein (BCRP/ABCG2) is a drug efflux transporter expressed at the blood cerebrospinal fluid barrier (BCSFB), and influences distribution of drugs into the central nervous systems (CNS). Current inhibitors have failed clinically due to neurotoxicity. Novel approaches are needed to identify new modulators to enhance CNS delivery. This study examines 18 compounds (mainly phytoestrogens) as modulators of the expression/function of BCRP in an in vitro rat choroid plexus BCSFB model.   METHODS:  Modulators were initially subject to cytotoxicity (MTT) assessment to determine optimal non-toxic concentrations. Reverse-transcriptase PCR and confocal microscopy were used to identify the presence of BCRP in Z310 cells. Thereafter modulation of the intracellular accumulation of the fluorescent BCRP probe substrate Hoechst 33342 (H33342), changes in protein expression of BCRP (western blotting) and the functional activity of BCRP (membrane insert model) were assessed under modulator exposure. RESULTS: A 24 hour cytotoxicity assay (0.001 µM-1000 µM) demonstrated the majority of modulators possessed a cellular viability IC50 > 148 µM. Intracellular accumulation of H33342 was significantly increased in the presence of the known BCRP inhibitor Ko143 and, following a 24 hour pre-incubation, all modulators demonstrated statistically significant increases in H33342 accumulation (P < 0.001), when compared to control and Ko143. After a 24 hour pre-incubation with modulators alone, a 0.16-2.5 -fold change in BCRP expression was observed for test compounds. The functional consequences of this were confirmed in a permeable insert model of the BCSFB which demonstrated that 17-β-estradiol, naringin and silymarin (down-regulators) and baicalin (up-regulator) can modulate BCRP-mediated transport function at the BCSFB. CONCLUSION: We have successfully confirmed the gene and protein expression of BCRP in Z310 cells and demonstrated the potential for phytoestrogen modulators to influence the functionality of BCRP at the BCSFB and thereby potentially allowing manipulation of CNS drug disposition.

 

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Author Biographies

Manjit Kaur, Aston University, School of Life and Health Sciences, Aston Triangle, Birmingham

School of Life and Health Sciences, Aston Pharmacy School.

PhD Student

Raj Kumar Singh Badhan, Aston University, School of Life and Health Sciences, Aston Triangle, Birmingham

School of Life and Health Sciences, Aston Pharmacy School.

Lecturer in Pharmacokinetics

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Published

2015-05-06

How to Cite

Kaur, M., & Badhan, R. K. S. (2015). Phytoestrogens Modulate Breast Cancer Resistance Protein Expression and Function at the Blood-Cerebrospinal Fluid Barrier. Journal of Pharmacy & Pharmaceutical Sciences, 18(2), 132–154. https://doi.org/10.18433/J3P31K

Issue

Section

Pharmaceutical Sciences; Review Articles