Fellner, Stephan and Bauer, Björn and Miller, David S. and Schaffrick, Martina and Fankhänel, Martina and Spruß, Thilo and Bernhardt, Günther and Graeff, Claudia and Färber, Lothar and Gschaidmeier, Harald and Buschauer, Armin and Fricker, Gert (2002) Transport of paclitaxel (Taxol) across the blood-brain barrier in vitro and in vivo. The Journal of Clinical Investigation 110 (9), pp. 1309-1318.
|PDF - Published Version|
Paclitaxel concentrations in the brain are very low after intravenous injection. Since paclitaxel is excluded from some tumors by p-glycoprotein (p-gp), the same mechanism may prevent entry into the brain. In vitro, paclitaxel transport was examined in capillaries from rat brains by confocal microscopy using BODIPY Fl-paclitaxel. Western blots and immunostaining demonstrated apical expression of p-gp in isolated endothelial cells, vessels, and tissue. Secretion of BODIPY Fl-paclitaxel into capillary lumens was specific and energy-dependent. Steady state luminal fluorescence significantly exceeded cellular fluorescence and was reduced by NaCN, paclitaxel, and SDZ PSC-833 (valspodar), a p-gp blocker. Leukotriene C4 (LTC4), an Mrp2-substrate, had no effect. Luminal accumulation of NBDL-cyclosporin, a p-gp substrate, was inhibited by paclitaxel. In vivo, paclitaxel levels in the brain, liver, kidney, and plasma of nude mice were determined after intravenous injection. Co-administration of valspodar led to increased paclitaxel levels in brains compared to monotherapy. Therapeutic relevance was proven for nude mice with implanted intracerebral human U-118 MG glioblastoma. Whereas paclitaxel did not affect tumor volume, co-administration of paclitaxel (intravenous) and PSC833 (peroral) reduced tumor volume by 90%. Thus, p-gp is an important obstacle preventing paclitaxel entry into the brain, and inhibition of this transporter allows the drug to reach sensitive tumors within the CNS.
|Institutions:||Chemistry and Pharmacy > Institute of Pharmacy > Pharmaceutical/Medicinal Chemistry II (Prof. Buschauer)|
|Subjects:||500 Science > 570 Life sciences|
600 Technology > 610 Medical sciences Medicine
|Refereed:||Yes, this version has been refereed|
|Created at the University of Regensburg:||Yes|
|Owner:||Prof. Armin Buschauer|
|Deposited On:||21 Feb 2008 10:33|
|Last Modified:||18 Nov 2013 13:51|