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This study evaluated the effect of electron beam irradiation on the cytotoxic activity of anthracycline antibiotics such as doxorubicin (DOX), epirubicin (EPI), and dunorubicin (DAU) in human acute lymphoblastic leukemia cell line CCRF-CEM and its multidrug-resistant variant CCRF-VCR1000 cell line characterized by the overexpression of ABCB1 gene. Drugs were irradiated at doses of 10 and 25 kGy. Data from EPR studies proved that the highest concentration of free radicals was found in DOX and that the number of stable free radicals is always greater after irradiation. In in vitro studies, a higher cytotoxic activity of irradiated DOX and EPI in multidrug-resistant CCRF-VCR1000 cells was observed. This tendency was maintained during the storage at 4 °C for 90 days. Changes in CCRF-CEM cells' viability were not dependent on the irradiation status and its dose and were only drug-concentration dependent in all measurement time points. It was proved that increased potency of 25 kGy e-beam irradiated drugs results from their enhanced proapoptotic activity. Apoptotic cell death observed in CCRF-VCR1000 cells treated with irradiated drugs was caspase-8, -9, and -3 dependent and related to the increased Bax/Bcl-2 ratio. No significant differences in the effects of irradiated and non-irradiated drugs on p53 and NFκB transcription factor level and their translocation to the nucleus were noted. Increased activity of the irradiated drugs was not dependent on ABCB1 level., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Background/aim: The ability of five formamidinodoxorubicins to induce apoptosis of MCF-7 breast cancer cells was tested. All these compounds were modified at C-3' and contain a formamidine group (-N=CH-NRR), with the rest of the cyclic secondary amine (HNRR) of a gradually increasing ring size., Materials and Methods: Cytotoxicity was assessed using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. To analyze apoptosis, double staining using fluorescence probes Hoechst 33258/propidium iodide (PI) and annexin V- Fluorescein isothiocyanate/PI was carried-out. Additionally, the TdT-mediated dUTP nick-end labelling test and activity of caspase 3 were determined., Results: The four tested derivatives displayed a significant increase in antiproliferative activity in comparison to doxorubicin. All of the tested derivatives induced caspase-dependent apoptosis of MCF-7 cells., Conclusion: DOX-F MOR and DOX-F PAZ analogs are more potent apoptosis inducers than doxorubicin., (Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Background/aim: Structural modifications of daunorubicin are an important way to change its anticancer activity. For this reason, formamidinodaunorubicins have been synthesized. The present study was undertaken to determine and compare the in vitro effects of daunorubicin and its new formamidine derivatives on human acute leukemia MOLT-4 and ML-1 cells., Materials and Methods: The experiments were performed on human acute lymphoblastic leukemia MOLT-4 cells and human acute myeloblastic leukemia ML-1 cells. The study was conducted using flow cytometry and light microscopy methods., Results: The various patterns of temporary changes in the cell cycle and DNA fragmentation, as well as the extent of mitotic catastrophe, apoptosis, and necrosis, were determined. The anti-leukemic activities of the new daunorubicin analogs were weaker than that of daunorubicin., Conclusion: The influence of these anthracyclines on cell-cycle progression, DNA damage, and induction of mitotic catastrophe and cell death depended on the agent and its concentration, the time interval after application, and the cell line used. The structural modifications of daunorubicin were responsible for the different cytotoxic effects of the two formamidinodaunorubicins., (Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Background/aim: The comparative effects of daunorubicin, and its new formamidine derivatives containing either a morpholine moiety (DAUFmor) or a hexamethyleneimine moiety (DAUFhex) in the amidine group, on induction of programmed cell death were determined., Materials and Methods: The experiments were performed on human acute lymphoblastic leukemia MOLT-4 cells and human acute myeloblastic leukemia ML-1 cells. The research was conducted using the flow cytometry annexin V-fluorescein (FITC)/propidium iodide (PI) method and tetramethylrhodamine ethyl ester (TMRE) assay., Results: The various patterns of temporary changes of early apoptotic cells, late apoptotic and necrotic cells, and in the frequency of the acute leukemia cells with high values of mitochondrial membrane potential (MMP) were found. Phosphatidylserine externalization, plasma membrane disruption, and changes in MMP occurring in the leukemia cells were dependent on the agent tested, its concentration, the time intervals after daunorubicin, DAUFmor, and DAUFhex application, and on the leukemia cell line used., Conclusion: The structural modifications of daunorubicin producing two new analogs, DAUFmor and DAUFhex, induced the different responses of MOLT-4 and ML-1 cells to triggering of programmed death.