Background:Flavonoids are natural compounds with antioxidant, anticarcinogenic, and anti-inflammatory effects.Aims:To determine the cytotoxic effects of flavonoids and drug resistance related to P-gp on K562 human chronic myeloid leukemia cells. We also aimed to evaluate the therapeutic potential of imatinib and flavonoid combinations.Study Design:Cell culture study.Methods:In this study, K562 cells were treated with apigenin, luteolin, 5-desmethyl sinensetin and the anticancer drug imatinib mesylate. The effect of flavonoids on K562 cell proliferation was detected using the 3-(4,5-dimethylthiazolyl)2,5‑diphenyl‑tetrazolium bromide assay. Concentrations of apigenin, luteolin, and 5-desmethyl sinensetin ranging from 25 to 200 μM and of imatinib from 5 to 50 μM administered for 72 h were studied. Apoptosis/necrosis and P-gp activity were measured using flow cytometry. The combined effects of different concentrations of flavonoids with imatinib were evaluated according to combination index values calculated using CompuSyn software.Results:In our study, the IC50 values for apigenin, luteolin, and 5-desmethyl sinensetin were found to be 140 μM, 100 μM, and >200 μM, respectively. Luteolin (100 μM) had the highest cytotoxic activity of these flavonoids. These results were statistically significant (p<0.05). Among the flavonoids studied, the combination of luteolin and imatinib was the most effective and is therefore recommended for its cytotoxic activity in the K562 cell line. After 72 h of incubation at their respective IC50 concentrations, all flavonoids were associated with an apoptosis rate of approximately 50%. P-glycoprotein activity was increased in all groups. Combination treatment may provide better outcomes in terms of cytotoxicity and thus reduce the dosages of imatinib used.Conclusion:The combination of some flavonoids and imatinib mesylate may increase the cytotoxic effect; However, the antagonistic effect should be considered in combined use on k562 cells.

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Nine iron(III) complexes, [Fe(L)Cl], were synthesized starting from S-alkylthiosemicarbazones and some substituted aldehydes. The L ligands formed by template condensation are N 2 O 2-chelating structures and named N 1acetylacetone-N 4-R-salicylidene-S-alkyl-thiosemicarbazidato (L 2−) where alkyl = methyl, propyl, or allyl and R = 3-methoxy, 4-methoxy, or 3,5-dichloro. The complexes were characterized using elemental analysis, IR, and ESI-MS. X-ray diffraction analysis of complex Fe8 (as a representative sample) indicated a square pyramid environment of the iron ion. The cytotoxicity performances of the complexes were determined using chronic myelogenous leukemia (K562), Burkitt's lymphoma (P3HR1), and T-cell leukemia (JURKAT) cell lines. For comparison, the noncancerous cell lines, human umbilical vein endothelial (HUVEC) and diploid fibroblast (3T3), and imatinib as positive control were included in the study. MTT results revealed that complexes Fe2, Fe5, Fe7, and Fe8 with methoxy (OCH 3) substituent have remarkable cytotoxic effects on K562 and P3HR1 cells at relatively low concentrations in the ranges of 4.81-14.05 and 5.61-11.98 μM, respectively. The radical scavenging activities of the complexes were measured for DPPH, superoxide anion (O 2 •−), hydroxyl (•OH) radicals, and hydrogen peroxide (H 2 O 2). Complexes Fe2, Fe3, Fe5, and Fe8, which exhibited selective cytotoxicity, were able to compete also with vitamin E in terms of ROS scavenging activities.

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Background: Flavonoids are natural compounds with antioxidant, anticarcinogenic, and anti-inflammatory effects. Aims: To determine the cytotoxic effects of flavonoids and drug resistance related to P-gp on K562 human chronic myeloid leukemia cells. We also aimed to evaluate the therapeutic potential of imatinib and flavonoid combinations. Study Design: Cell culture study. Methods: In this study, K562 cells were treated with apigenin, luteolin, 5-desmethyl sinensetin and the anticancer drug imatinib mesylate. The effect of flavonoids on K562 cell proliferation was detected using the 3-(4,5-dimethylthiazolyl)2,5-diphenyl-tetrazolium bromide assay. Concentrations of apigenin, luteolin, and 5-desmethyl sinensetin ranging from 25 to 200 μM and of imatinib from 5 to 50 μM administered for 72 h were studied. Apoptosis/necrosis and P-gp activity were measured using flow cytometry. The combined effects of different concentrations of flavonoids with imatinib were evaluated according to combination index values calculated using CompuSyn software. Results: In our study, the IC 50 values for apigenin, luteolin, and 5-desmethyl sinensetin were found to be 140 μM, 100 μM, and >200 μM, respectively. Luteolin (100 μM) had the highest cytotoxic activity of these flavonoids. These results were statistically significant (p<0.05). Among the flavonoids studied, the combination of luteolin and imatinib was the most effective and is therefore recommended for its cytotoxic activity in the K562 cell line. After 72 h of incubation at their respective IC 50 concentrations, all flavonoids were associated with an apoptosis rate of approximately 50%. P-glycoprotein activity was increased in all groups. Combination treatment may provide better outcomes in terms of cytotoxicity and thus reduce the dosages of imatinib used. Conclusion: The combination of some flavonoids and imatinib mesylate may increase the cytotoxic effect; However, the antagonistic effect should be considered in combined use on k562 cells.

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