Related Experiment Video
Updated: Apr 7, 2026
Systems Biology of Metabolic Regulation by Estrogen Receptor Signaling in Breast Cancer
Published on: March 17, 2016
Phytoestrogens Modulate Breast Cancer Resistance Protein Expression and Function at the Blood-Cerebrospinal Fluid
Manjit Kaur1, Raj Kumar Singh Badhan
1Aston University, School of Life and Health Sciences, Aston Triangle, Birmingham.
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.
Insights
Phytoestrogens can modulate breast cancer resistance protein (BCRP/ABCG2) activity at the blood-cerebrospinal fluid barrier. This research identifies potential compounds to enhance drug delivery to the central nervous system (CNS).
Area of Science:
- Neuroscience
- Pharmacology
- Biochemistry
Background:
- Breast cancer resistance protein (BCRP/ABCG2) is a key efflux transporter at the blood-cerebrospinal fluid barrier (BCSFB).
- BCRP influences drug distribution into the central nervous system (CNS), impacting therapeutic efficacy.
- Existing BCRP inhibitors cause neurotoxicity, necessitating novel strategies for CNS drug delivery.
Purpose of the Study:
- To investigate phytoestrogens as modulators of BCRP expression and function at the BCSFB.
- To identify novel compounds for enhancing CNS drug delivery by targeting BCRP.
- To evaluate the potential of 18 compounds, primarily phytoestrogens, in an in vitro rat choroid plexus BCSFB model.
Main Methods:
- Cytotoxicity assessment (MTT assay) to determine non-toxic concentrations of modulators.
- Reverse-transcriptase PCR and confocal microscopy to confirm BCRP presence in Z310 cells.
- Assays for intracellular accumulation of Hoechst 33342, BCRP protein expression (western blotting), and functional activity in a membrane insert model.
Main Results:
- Most compounds exhibited high cellular viability IC50 (>148 µM).
- All tested phytoestrogens significantly increased intracellular accumulation of the BCRP substrate Hoechst 33342.
- Compounds modulated BCRP expression (0.16-2.5 fold change) and BCRP-mediated transport function at the BCSFB.
Conclusions:
- BCRP gene and protein expression were confirmed in Z310 cells.
- Phytoestrogen compounds demonstrate potential to modulate BCRP functionality at the BCSFB.
- These findings suggest a strategy for manipulating CNS drug disposition via BCRP modulation.
Related Concept Videos
02:59Cancer Prevention
Some...
02:38Mitogens and the Cell Cycle
01:23Factors Affecting Drug Distribution: Physiological Barriers
The capillary endothelial barrier allows only smaller molecules below 600 Da (Daltons) to pass through. It also restricts drugs like heparin that are bound to blood components, limiting their movement within the bloodstream.
The...