The Connection between the Toxicity of Anthracyclines and Their Ability to Modulate the P-Glycoprotein-Mediated Transport in A549, HepG2, and MCF-7 Cells

Multidrug resistance (MDR) is a major obstacle to the successful chemotherapy of solid tumors. We compared the resistance of the most popular solid tumors, breast adenocarcinoma (MCF-7 cell line) and nonsmall cell lung (A549 cell line) hepatocellular liver carcinoma (HepG2 cells), to aclarubicin (ACL) and doxorubicin (DOX). This research aimed at determining the relation between the toxicity of ACL and DOX, their cell accumulation, and then effect on P-glycoprotein functionality. ACL is more cytotoxic for tumor cells compared to DOX. The intracellular concentration of drugs in cancer cells was dependent on the dose of the drugs and the time of incubation. The P-gp inhibitor Verapamil (V) increased DOX accumulation in all tested cell lines. By contrast, the intracellular level of ACL was not affected by this modifying agent. The assessment of the uptake of 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazolocarbocyanine iodide (JC-1) or Rhodamine 123 (R123) allows the evaluation of the different influence of drugs on P-gp activity which is in agreement with the estimation of expression measured by MDR-1 shift assay. These data suggest that ACL is less P-gp dependent than DOX and consequently may be used in a clinical setting to increase treatment efficacy in resistant human tumors

Transport of organic anions by multidrug resistance-associated protein in the erythrocyte.

The active transport of oxidized glutathione and glutathione S-conjugates has been demonstrated for the first time in erythrocytes and this cell remained the main subject of research on the "glutathione S-conjugate pump" for years. Further studies identified the "glutathione S-conjugate pump" as multidrug resistance-associated protein (MRP). Even though cells overexpressing MRP and isolated MRP provide useful information on MRP structure and function, the erythrocyte remains an interesting model cell for studies of MRP1 in its natural environment, including the substrate specificity and ATPase activity of the protein

Development of Half-Sandwich Ru, Os, Rh, and Ir Complexes Bearing the Pyridine-2-ylmethanimine Bidentate Ligand Derived from 7-Chloroquinazolin-4(3H)-one with Enhanced Antiproliferative Activity.

Kinesin spindle protein (KSP) inhibitors are one of the most promising anticancer agents developed in recent years. Herein, we report the synthesis of ispinesib-core pyridine derivative conjugates, which are potent KSP inhibitors, with half-sandwich complexes of ruthenium, osmium, rhodium, and iridium. Conjugation of 7-chloroquinazolin-4(3H)-one with the pyridine-2-ylmethylimine group and the organometallic moiety resulted in up to a 36-fold increased cytotoxicity with IC50 values in the micromolar and nanomolar range also toward drug-resistant cells. All studied conjugates increased the percentage of cells in the G2/M phase, simultaneously decreasing the number of cells in the G1/G0 phase, suggesting mitotic arrest. Additionally, ruthenium derivatives were able to generate reactive oxygen species (ROS); however, no significant influence of the organometallic moiety on KSP inhibition was observed, which suggests that conjugation of a KSP inhibitor with the organometallic moiety modulates its mechanism of action

Ferrocene-Biotin Conjugates: Synthesis, Structure, Cytotoxic Activity and Interaction with Avidin

Friedel–Crafts acylation of ferrocene with d‐biotin, d‐homobiotin and d‐desthiobiotin gave ferrocenyl ketones. These compounds were diastereoselectively reduced to the corresponding alcohols using (R)‐ and (S)‐Me‐CBS‐oxazaborolidine–borane complexes as reducing agents. The alcohols were further transformed into azido and finally to amino derivatives with retention of configuration, as confirmed by X‐ray crystallography. Ferrocenylbiotin alcohols smoothly underwent dehydration to (E)‐alkenes as the major isomers by heating in diluted acetic acid. The synthesized compounds retained high affinity for avidin. They also exhibited high cytotoxicity toward cancer cells expressing various levels of sodium‐dependent multivitamin transporter (SMVT) in the absence of biotin in the medium, whereas the presence of free biotin decreased their antiproliferative activity. This revealed that these biotin–ferrocene conjugates might be used as biologically active agents against cancer cells, although there was no clear relationship between their cytotoxicity and cellular SMVT level