[Involvement of mitochondria apoptotic pathway in the manumycin inducing apoptosis of U937 and HL-60].
OBJECTIVE
To investigate the apoptosis induced by manumycin in U937 and HL-60 cell lines, and to explore the role of mitochondria apoptotic pathway in manumycin-inducing apoptosis.


METHODS
Leukemic cells line U937 and HL-60 were treated by manumycin at 2 micromol/L for different time. Apoptosis of leukemia cells was detected by flow cytometry. The cytosolic proteins were extracted using a digitonin buffer. The protein expression of cytochrome C, caspase-9, caspase-8, and caspase-3 were determined by western blot. Mitochondrial membrane potential was detected by JC-1.


RESULTS
In U937 and HL-60 cells, manumycin induced mitochondrial depolarization after 6 h treatment. The average red/green fluorescence ratios at 6 h were significantly (P < 0.01) lower than those at time 0, being 0.51 +/- 0.07 and 0.41 +/- 0.06 for control group respectively. Manumycin induced cytochrome C release from the mitochondria into the cytosol after 6 h treatment, and activated caspase-9, caspase-8, and caspase-3 after a 16h treatment. The broad-spectrum caspase-inhibitor Z-VAD-fmk at 50 micromol/L was able to inhibit caspase cleavage completely, but only reduced the manumycin-induced apoptosis rates by 51.69% and 56.47% in U937 and HL-60, respectively.


CONCLUSIONS
Manumycin induced apoptosis in U937 and HL-60 cell lines via mitochondria apoptotic pathway.
She
Miao-rong
MR
Department of Hematology, Guangdong Provincial People's Hospital, Guangzhou 510080, China.
Li
Jin-gao
JG
Du
Xin
X
Lin
Wei
W
Niu
Xin-qing
XQ
Guo
Kun-yuan
KY
D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D018922:HL-60 Cells; D006801:Humans; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D011090:Polyenes / Q000494:pharmacology*; D053284:Polyunsaturated Alkamides / Q000494:pharmacology*
D011090:Polyenes; D053284:Polyunsaturated Alkamides; D045304:Cytochromes c; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; C054474:manumycin