[Apoptosis-inducing effect of carbazole alkaloid (HY-1) in human erythroleukemia K562 cells].
OBJECTIVE
To investigate apoptosis-inducing effect and its mechanisms of HY-1, a carbazole alkaloid, on human erythroleukemia K562 cells.


METHODS
Cell proliferation was detected by sulforhodamine B (SRB) assay after treated with HY-1 at indicated doses. Cell cycle analysis was performed by flow cytometry, mitochondria membrane voltage change was assessed by rhodamine 123 staining, annexin V-PI apoptosis detecting kit and DNA agarose gel electrophoresis were used to identify apoptosis-inducing effect of HY-1. The alterations of apoptosis-relating proteins were detected by Western blot.


RESULTS
The IC(50) of HY-1 in K562 cells was (29.05 +/- 0.90) micromol/L by SRB assay. HY-1 had significant apoptotic inducing effect on K562 cells in a dose- and time-dependent manner as verified by appearance of Sub-G(1) peak on histogram of flow cytometry analysis, reduction of mitochondria membrane voltage, appearance of double positive cell group in Annexin V-PI apoptosis detecting test, and remarkable DNA ladder. The expression of cytosolic cytochrome c was apparently increased. Pro-caspase-9, pro-caspase-3 and PARP were all cleaved to active segments. There was no change in the expression of caspase-8.


CONCLUSIONS
HY-1 exerts its anticancer activity through triggering apoptosis of K562 cells by mitochondria-activating pathways.
Cai
Ying
Y
Tianjin Institute for Biomedicinal Research, Tianjin, 300384, China.
Cai
Bing
B
Cui
Cheng-bin
CB
Zhang
Dong-yun
DY
Han
Bing
B
Wang
Yuan-guo
YG
Wang
Min-wei
MW
D000470:Alkaloids / Q000302:isolation & purification / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002227:Carbazoles / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D020014:K562 Cells; D008928:Mitochondria / Q000378:metabolism; D027821:Rutaceae / Q000737:chemistry*
D000470:Alkaloids; D000972:Antineoplastic Agents, Phytogenic; D002227:Carbazoles; C041514:carbazole