Modification of uptake and subcellular distribution of doxorubicin by N-acylhydrazone residues as visualised by intrinsic fluorescence

Abstract

Purpose: Doxorubicin (1) is commonly used in the treatment of a wide range of cancers. Some N-acylhydrazones of 1 were previously found to have an improved tumour and organ selectivity. In order to clarify the molecular basis for this effect, the cellular uptake into various cancer cells and the localisation in PtK 2 potoroo kidney cells of 1 and its N-acylhydrazones derived from heptadecanoic acid (2) and 11-(menthoxycarbonyl)undecanoic acid (3) were studied drawing on their intrinsic fluorescence.

Mitochondrial-Targeting Nitrooxy-doxorubicin: A New Approach To Overcome Drug Resistance

“…In keeping with our observation on the mitochondrial localization of NitDOX, it has been reported that synthetic acyl-conjugated DOXs, more hydrophobic than the parental drug, are more uptaken by drug-resistant cells and display a cytosolic rather than a nuclear localization. 35 Also, the level of ABC transporters in subcellular compartments, which is highly variable and cell type-dependent, 36−38 strongly affects the intracellular distribution of anthracyclines. In our model, the rate of nitration and extrusion activity of Pgp/ABCB1, MRP1/ABCC1, and BCRP/ABCG2 did not appear to underlie the nuclear-cytosolic partition of DOX and NitDOX.…”

Utilizing inherent fluorescence of therapeutics to analyze real-time uptake and multi-parametric effector kinetics

“…Commonly, the cellular uptake of drugs is quantified by indirect methods such as analyzing the remaining amount of drug in the supernatant of treated cultures [7]. As we have observed a Doxorubicin-induced dose dependent cellular fluorescence increase by flow cytometry, we demonstrate that a direct and precise quantification of cell-bound Doxorubicin is possible.…”

“…The drug has an inherent fluorescence frequently used in a variety of different assays [2,7]. Here we use Doxorubicin as the principle model substance.…”

“…As we have observed a Doxorubicin-induced dose dependent cellular fluorescence increase by flow cytometry, we demonstrate that a direct and precise quantification of cell-bound Doxorubicin is possible. Furthermore, the Doxorubicin fluorescence remaining in the supernatant after 20 min was quantified [7], and the calculated uptake correlated directly with the increase in fluorescence for each respective Doxorubicin concentrations applied. The obtained results prove that the direct measurements of cellular fluorescence described are consistent with the indirect measurements obtained from data for the reduction of fluorescence measured in the supernatants, at least for 0.3-2.4 lM Doxorubicin doses (Fig.…”

“…As such, they exhibit complex structures with many delocalized electrons and many, for example Doxorubicin [4] and Camptothecin [5], possess inherent fluorescence, a valuable trait most often neglected. Current methods in the analysis of drug uptake include assays using radioactively labeled compounds [6], limited fluorescence microscopy [2] or measuring residual amounts of drug remaining in the supernatant after cell treatment [7]. These assays, besides being labor-intensive and time consuming, measure uptake indirectly using multiple samples in order to gain a limited endpoint-based kinetic analysis precluding any kind of multi-parametric co-analysis of effects caused by drug uptake.…”