Related Experiment Video
Updated: Oct 8, 2026
Methods to Study Mrp4-containing Macromolecular Complexes in the Regulation of Fibroblast Migration
Published on: May 19, 2016
Detection of MRP functional activity: calcein AM but not BCECF AM as a Multidrug Resistance-related Protein (MRP1)
D P Olson1, B J Taylor, S P Ivy
1Center for Cancer and Blood Disorders, Children's National Medical Center, Washington, DC, USA. Dolson3@bics.bwh.harvard.edu
Abstract:
Resistance to anticancer drugs has been attributed to an array of cellular changes. The multidrug resistance-related protein (MRP1) is an efflux pump whose overexpression confers resistance to several classes of drugs, such as the anthracyclines, epipodophyllotoxins, and vinca alkaloids. These drugs are mainstays in cancer therapy. MRP1 overexpression is hypothesized to be a causative agent of clinical treatment failure. Consistently accurate methods for detecting this protein are necessary to further understand its biology and delineate its possible clinical relevance. Flow cytometric analysis of multidrug resistance (MDR) is a valuable method to evaluate both antigen expression and function. Using flow cytometry, we assayed MRP1 functional activity in pediatric leukemic blasts and an array of MDR+ and WT cell lines. We conclude that calcein AM, when used in a retention assay with MRP1-specific modulators, is able to reliably detect MRP functional activity. 2'-7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF AM) transport is not indicative of MRP1 overexpression. .
Insights
Calcein AM retention assays reliably detect functional multidrug resistance-related protein 1 (MRP1) activity. This flow cytometry method accurately measures MRP1 function, crucial for understanding cancer drug resistance.
Area of Science:
- Biochemistry
- Molecular Biology
- Oncology
Background:
- Multidrug resistance-related protein 1 (MRP1) overexpression is a key factor in anticancer drug resistance.
- MRP1 efflux pump activity contributes to treatment failure in various cancers.
- Accurate methods to detect MRP1 are vital for clinical relevance and biological understanding.
Purpose of the Study:
- To evaluate flow cytometry for assessing MRP1 functional activity.
- To validate calcein AM retention assay for MRP1 functional detection.
- To determine if 2'-7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF AM) transport indicates MRP1 overexpression.
Main Methods:
- Flow cytometry was used to assay MRP1 functional activity.
- Calcein AM retention assay was employed with MRP1-specific modulators.
- Pediatric leukemic blasts and various cell lines (MDR+ and WT) were analyzed.
Main Results:
- Calcein AM retention assay reliably detects MRP1 functional activity.
- MRP1-specific modulators confirmed the assay's specificity.
- BCECF AM transport was found not to be indicative of MRP1 overexpression.
Conclusions:
- Calcein AM retention assay is a dependable method for measuring MRP1 functional activity.
- This assay can aid in understanding MRP1's role in cancer drug resistance.
- BCECF AM assay is unsuitable for detecting MRP1 overexpression.
