PT  - JOURNAL ARTICLE
AU  - GABRIELLA SPENGLER
AU  - MIGUEL VIVEIROS
AU  - MARTA MARTINS
AU  - LILIANA RODRIGUES
AU  - ANA MARTINS
AU  - JOZSEF MOLNAR
AU  - ISABEL COUTO
AU  - LEONARD AMARAL
TI  - Demonstration of the Activity of P-glycoprotein by a Semi-automated Fluorometric Method
DP  - 2009 Jun 01
TA  - Anticancer Research
PG  - 2173--2177
VI  - 29
IP  - 6
4099  - http://ar.iiarjournals.org/content/29/6/2173.short
4100  - http://ar.iiarjournals.org/content/29/6/2173.full
SO  - Anticancer Res2009 Jun 01; 29
AB  - Background: We have developed a semi-automated fluorometric method that utilizes ethidium bromide (EB), a common substrate of bacterial efflux pumps. The method is sufficiently sensitive to characterize the efflux pump systems of bacteria. Because EB is also recognized and extruded by ATP-binding cassette (ABC) transporters and these have similarity to P-glycoprotein (P-gp), the method has been extended for the evaluation of agents that can inhibit the extrusion of EB on a real-time basis by mouse lymphoma cells containing the human ABCB1 (mdr1) gene. Materials and Methods: Monitoring of uptake and extrusion of EB was assessed using the Rotor-Gene™ 3000 (Corbett Research) under different conditions. Results: Whereas extrusion of EB took place readily, the addition of known inhibitors of efflux pumps (verapamil, reserpine) caused retention of EB. Conclusion: This method is inexpensive and allows the detection of neoplastic cells with increased efflux activity as well as the screening of large numbers of compounds for inhibition of the P-gp.