[Induction of apoptosis by proteasome inhibitor MG-132 in human erythroleukemia cell line K562].
OBJECTIVE
To investigate whether proteasome inhibitor MG-132 induces apoptosis of human erythroleukemia cell line K562 and possible mechanisms.


METHODS
K562 cells were incubated with RPMI 1640 and exposed to 0, 1, 5, 10, 15 micromol/L of MG-132 for 24 hrs, respectively. The apoptosis of cells were detected by fluorescence microscope, DNA fragments and flow cytometry. The NF-kappaB mRNA expression was quantified by reverse transcription-polymerase chain reaction (RT-PCR). Expression of NF-kappaB and caspase-3 was semiquantitatively analyzed with SABC techniques. Caspase-3 activities were measured with a colorimetric method.


RESULTS
The growth of K562 cells was inhibited and the apoptosis of the cells increased after MG-132 treatment in a dose-dependent manner. After 24 hrs of 15 micromol/L MG-132 treatment, the percentage of apoptotic cells (26.5+/-0.6%) increased significantly when compared with the untreated controls (1.2+/-0.1%) (P<0.01). MG-132 treatment decreased the mRNA and protein expression of NF-kappaB, and increased the protein expression of caspase-3.


CONCLUSIONS
MG-132 can induce apoptosis of human erythroleukemia cell line K562 through the down-regulation of NF-kappaB expression and up-regulation of caspase-3 expression.
Department of Pediatrics, Third Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China.
Xi-Ge
XG
Wang
Qing-Fei
QF
Hao
You-Cai
YC
Tang
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D020014:K562 Cells; D007976:Leupeptins / Q000494:pharmacology*; D016328:NF-kappa B; D061988:Proteasome Inhibitors; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000970:Antineoplastic Agents; D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D016328:NF-kappa B; D061988:Proteasome Inhibitors; D053148:Caspase 3; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde