[Effect of (-)-epigallocatechin-3-gallate and 5-AZA-CdR on expression of X-linked inhibitor of apoptosis protein-associated factor 1 in human leukemia HL-60 and K562 cells].
OBJECTIVE
To study the expression of X-linked inhibitor of apoptosis protein (XIAP)-associated factor 1 (Xaf1) in human leukemia HL-60 and K562 cells treated with interferon alpha (INFalpha) and the demethylating agent 5-AZA-CdR, and observe the synergetic antitumor effect of Xaf1 inducer and (-)-epigallocatechin-3-gallate (EGCG).


METHODS
Human leukemia HL-60 and K562 cells were treated for 48 h with 1000 U/ml INFalpha and different doses of 5-AZA-CdR, and the mRNA expressions of both Xaf1 and XIAP were measured by RT-PCR. The leukemia cells were also treated with the optimal Xaf1 inducer in combination with EGCG, after which flow cytometry was employed to examine the changes in the members of the Bcl-2 family, mitochondrial transmembrane potential and apoptosis.


RESULTS
As the dose increased, 5-AZA-CdR dose-dependently up-regulated the mRNA expression of Xaf1 in HL-60 and K562 cells; INFalpha treatment also resulted in increased Xaf1 expression, but 5 micromol/L 5-AZA-CdR showed the most potent effect. Neither INFalpha nor 5-AZA-CdR caused significant changes in XIAP expression. Combined treatment with 5-AZA-CdR and EGCG altered the expressions of Bcl-2 (Bcl-xl) and Bax in HL-60 and K562 cells, decreased the mitochondrial transmembrane potential and induced cell apoposis, and the two agents exhibited obvious synergistic effect.


CONCLUSIONS
INFalpha and 5-AZA-CdR can induce Xaf1 mRNA expressions in HL-60 and K562 cells, and the effect of 5-AZA-CdR was dose-dependent. 5-AZA-CdR and EGCG induces apoptosis of leukemia cells in vitro, and they exhibits obvious synergetic effects.
Huang
Yun-yan
YY
Department of Pediatrics, College of Clinical Medicine, Guangdong Pharmaceutical University, Guangzhou 510006, China. yyhuang586@126.com
Xia
Yan
Y
Guo
Hai-xia
HX
Li
Wen-yi
WY
D048868:Adaptor Proteins, Signal Transducing; D016588:Anticarcinogenic Agents / Q000494:pharmacology; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D004357:Drug Synergism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D018922:HL-60 Cells; D006801:Humans; D016898:Interferon-alpha; D047908:Intracellular Signaling Peptides and Proteins; D020014:K562 Cells; D009363:Neoplasm Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D015854:Up-Regulation; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D016588:Anticarcinogenic Agents; D000964:Antimetabolites, Antineoplastic; D051017:Apoptosis Regulatory Proteins; D016898:Interferon-alpha; D047908:Intracellular Signaling Peptides and Proteins; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D051636:X-Linked Inhibitor of Apoptosis Protein; C417551:XAF1 protein, human; D051028:bcl-2-Associated X Protein; D002392:Catechin; C045651:epigallocatechin gallate; D001374:Azacitidine