Abstract
Doxorubicin delivery to the brain is often restricted because of the poor transport of this therapeutic molecule through the blood-brain barrier (BBB). To overcome this problem, we have recently developed a technology, Pep:trans, based on short natural-derived peptides that are able to cross efficiently the BBB without compromising its integrity. In this study, we have used the in situ mouse brain perfusion method to evaluate the brain uptake of free and vectorized doxorubicin. Doxorubicin was coupled covalently to small peptide vectors:l-SynB1 (18 amino acids), l-SynB3 (10 amino acids), and its enantio form d-SynB3. We first confirmed the very low brain uptake of free radiolabeled doxorubicin, which is most likely due to the efflux activity of the P-glycoprotein at the level of the BBB. Vectorization with either l-SynB1,l-SynB3, or d-SynB3 significantly increased the brain uptake of doxorubicin (about 30-fold). We also investigated the mechanism of transport of vectorized doxorubicin. We show that vectorized doxorubicin uses a saturable transport mechanism to cross the BBB. The effect of poly(l-lysine) and protamine, endocytosis inhibitors, on the transport across the brain was also investigated. Both inhibitors reduced the brain uptake of vectorized doxorubicin in a dose-dependent manner. These studies indicate that the transport of vectorized doxorubicin appears to occur via an adsorptive-mediated endocytosis.
Footnotes
-
Send reprint requests to: Jamal Temsamani, Synt:em, Parc Scientifique Georges Besse, 30000 Nı̂mes, France. E-mail:jtemsamani{at}syntem.com
-
This study was supported partly by the Anvar Languedoc Roussillon.
- Abbreviations:
- BBB
- blood-brain barrier
- HPLC
- high performance liquid chromatography
- TFA
- trifluoroacetic acid
- dox
- doxorubicin
- DMF
- dimethylformamide
- P-gp
- P-glycoprotein
- Received July 6, 2000.
- Accepted September 22, 2000.
- The American Society for Pharmacology and Experimental Therapeutics
JPET articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|