Direct evaluation of intracellular accumulation of free and polymer-bound anthracyclines

Abstract

Nanoparticulate carriers of anthracyclines are being developed with the aim of improving the pharmacokinetic or pharmacodynamic behavior of these drugs. To understand how the drug reaches its nuclear targets, we have developed two methods that allow the quantification of the interaction between an anthracycline and cellular DNA: (1) by direct evaluation of the quenching of anthracycline fluorescence due to the intercalation of the drug into DNA and (2) by the measurement of Hoechst 33258 fluorescence associated with its displacement from DNA-binding sites for which it competes with the anthracycline. We show that the intracellular accumulation and DNA binding of doxorubicin encapsulated in polyisohexylcyanoacrylate nanospheres (dox-NS) and of daunorubicin bound to polyglutamic acid are reduced by 30%-40% in comparison with those obtained for free doxorubicin (dox) and daunorubicin, respectively. The results obtained with dox or NS-dox are not modified by prior incubation with either of these compounds. The two methods yielded similar results, and we conclude that either technique is applicable to the evaluation of the interaction of carrier-bound anthracyclines with cellular DNA.

Molecular requirements for doxorubicin-mediated death in murine oocytes

“…This would rule out the possibility that quenching of DXR fluorescence, a concern in the present studies, was not due to the interaction of the chemotherapeutic drug with lipids or other molecules in the intracellular environment. 30 The observations we made using fluorescence microscopy in the present experiments also indicate that, the cytoplasm and chromosomal DNA of both DXR-sensitive (WT) and -resistant (ASMase-null) oocytes are primary targets for DXR. Moreover, early interference with either DXR uptake or DNA retention is crucial for the prevention of DNA damage induced by DXR.…”

The endocytic pathway and therapeutic efficiency of doxorubicin conjugated cholesterol-derived polymers

“…17 One of the many approaches to overcome these limitations and enhance the efficacy of DOX is by utilizing polymers as drug carriers. Various polyanions such as polyglutamate; 18 polyaspartate, 19 poly(acrylic acid), 20,21 γ-polyglutamic acid, 22 block ionomers of aspartate, benzyl glutamate 23 and benzyl aspartate 24 with poly-(ethylene oxide) have demonstrated encouraging results in terms of binding and delivering DOX into targeted cells and tissues. Consequently, anionic poly(methacrylic acid-co-cholesteryl methacrylate) P(MAA-co-CMA) copolymer series -comprised of enriched electrostatic binding abilities and pHresponsive/membrane disruptive properties -were investigated as potential DOX carriers.…”

Polyanionic carbohydrate doxorubicin–dextran nanocomplex as a delivery system for anticancer drugs: in vitro analysis and evaluations

“…24,25 DOX possesses positive charge and has been studied for its complexation with various anionic polymers such as poly(acrylic acid), 26,27 γ-polyglutamic acid, 28 polyaspartate, 24,29 polyglutamate, 30 block ionomers of aspartate, benzyl aspartate, [31][32][33][34] benzyl glutamate, 29 and polyethylene oxide. These polyanions form polyelectrolyte complexes with DOX.…”