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CPT-B1
Welcome! You must be here because you’ve heard the buzz about CPT-B1, the first of the CellPort Technologies® cell lines from Absorption Systems. Hopefully you will learn all you want to know about CPT-B1 on this page, but if not please contact Absorption Systems and we’ll be happy to help. Check back often…we will continue to post the latest information on this and other CellPort Technologies cell lines.
View the new ebook, Transporter Reference Guide .
You may be aware that, prior to the introduction of CPT-B1, there was an unmet need for a definitive human BCRP assay system. Researchers all over the world are jumping on the bandwagon.
Absorption Systems Video Trailers
We created CPT-B1 by using RNA interference to knock down the expression of BCRP in a stable clone of human Caco-2 cells. Go to our Literature page to see posters that we presented on this topic at various scientific meetings. One poster was also presented as an assay tutorial in the February 15, 2008 issue of Genetic Engineering and Biotechnology News (GEN).
Based on quantitative PCR, expression of BCRP mRNA in CPT-B1 is reduced greater than 90% relative to control cells:
BCRP function is also greatly reduced:
We use CPT-B1 in two different applications:
- As a standalone model to identify and characterize P-gp substrates, without interference by BCRP (unlike wild-type Caco-2 cells). To identify P-gp substrates, we run bidirectional transport assays with test compounds in the presence and absence of cyclosporine A (CsA), a P-gp inhibitor. P-gp substrates have a high efflux ratio in the absence of CsA and an efflux ratio near 1 in the presence of CsA.
- In combination with wild-type Caco-2 cells to identify BCRP substrates. We run bidirectional transport assays with both CellPort Pgp and wild-type Caco-2 cells in parallel. BCRP substrates have a higher efflux ratio in wild-type cells (which express BCRP) than in CellPort Pgp (in which BCRP expression has been knocked down substantially).
Features of CellPort pgp:
- It is a human epithelial cell line (the FDA is interested in human protein-drug interactions)
- Human P-gp is expressed at a high level
- Human BCRP expression and function are reduced
- It is phenotypically stable
- Assay format is the same format specified in the 2006 FDA Draft Guidance on Drug Interaction Studies1
- For identifying and characterizing P-gp substrates, it is a cleaner model than either Caco-2 (lower BCRP activity) or MDR1-MDCK (no canine P-gp).
View the new ebook, Transporter Reference Guide .
Want to know how you can get your hands on CPT-B1? Contact Absorption Systems . We look forward to hearing from you.
View our overview video on drug transporters, including an introduction to CellPort Technologies™.
1FDA draft guidance on drug interaction studies: http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/UCM072101.pdf
Related Literature
This assay is used to determine the P-gp interaction with a test compound using CellPort™ CPT-B1 BCRP-knockdown cell monolayers in both the presence and the absence of a P-gp inhibitor.
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This assay is used to determine the BCRP interaction with a test compound using CellPort™ CPT-B1 BCRP-knockdown cell monolayers and wild-type Caco-2 cell monolayers.
Click Here to Download
Brochures
A unique, more definitive test system for identifying BCRP and P-gp substrates
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Services and products based on the novel, proprietary CellPort Technologies
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Introduction to CellPort Technologies, a more definitive drug transporter assay system
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In vitro testing to identify P-gp substrates, inhibitors and inducers
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