Chelerythrine and dihydrochelerythrine induce G1 phase arrest and bimodal cell death in human leukemia HL-60 cells.
A quaternary benzo[c]phenanthridine alkaloid chelerythrine displays a wide range of biological activities including cytotoxicity to normal and cancer cells. In contrast, less is known about the biological activity of dihydrochelerythrine, a product of chelerythrine reduction. We examined the cytotoxicity of chelerythrine and dihydrochelerythrine in human promyelocytic leukemia HL-60 cells. After 4h of treatment, chelerythrine induced a dose-dependent decrease in the cell viability with IC50 of 2.6 microM as shown by MTT reduction assay. Dihydrochelerythrine appeared to be less cytotoxic since the viability of cells exposed to 20 microM dihydrochelerythrine for 24h was reduced only to 53%. Decrease in the viability induced by both alkaloids was accompanied by apoptotic events including the dissipation of mitochondrial membrane potential, activation of caspase-9 and -3, and appearance of cells with sub-G1 DNA. Moreover, chelerythrine, but not dihydrochelerythrine, elevated the activity of caspase-8. A dose-dependent induction of apoptosis and necrosis by chelerythrine and dihydrochelerythrine was confirmed by annexin V/propidium iodide dual staining flow cytometry. Besides, both alkaloids were found to induce accumulation of HL-60 cells in G1 phase of the cell cycle. We conclude that both chelerythrine and dihydrochelerythrine affect cell cycle distribution, activate mitochondrial apoptotic pathway, and induce apoptosis and necrosis in HL-60 cells.
Vrba
Jirí
J
Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Hnevotínská 3, 775 15 Olomouc, Czech Republic. vrbambv@seznam.cz <vrbambv@seznam.cz>
Dolezel
Petr
P
Vicar
Jaroslav
J
Modrianský
Martin
M
Ulrichová
Jitka
J
D000470:Alkaloids / Q000008:administration & dosage / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D053119:Benzophenanthridines / Q000008:administration & dosage / Q000494:pharmacology*; D020169:Caspases / Q000187:drug effects / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D004273:DNA, Neoplasm / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D016193:G1 Phase / Q000187:drug effects; D018922:HL-60 Cells; D006801:Humans; D020128:Inhibitory Concentration 50; D015473:Leukemia, Promyelocytic, Acute / Q000188:drug therapy / Q000473:pathology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D013997:Time Factors
D000470:Alkaloids; D000970:Antineoplastic Agents; D053119:Benzophenanthridines; D004273:DNA, Neoplasm; C524982:dihydrochelerythrine; C016299:chelerythrine; D020169:Caspases