[Effect of lidamycin on mitochondria initiated apoptotic pathway in human cancer cells].
Although enediyne antibiotic lidamycin ( LDM) is a potent inducer of apoptosis, the underlying mechanisms of its apoptotic functions remain to be explored. Here, we aim to elucidate its possible mechanisms in mitochondria initiated apoptotic pathway involved in human BEL-7402 and MCF-7 cells. Cytochrome c released from mitchondria to cytosol fraction was detected by Western blotting. p53 and Bax, Bcl-2 expressions were detected by Western blotting and RT-PCR. MTT assay was used to detect cytotoxicity of LDM with or without caspase inhibitor z-VAD-fmk. After the BEL-7402 cells were exposed to 0. 1 micromol x L(-1) LDM within 6 h, the increase of cytochrome c in the cytosol and decrease in the mitochondria were observed when compared with untreated cells. The expression of Bax, an important proapoptotic member of the Bcl-2 family, increased gradually in the BEL-7402 cells after exposure to LDM of 0. 1 micromol x L (-1) for 2, 6, and 9 h, separately, while Bcl-2 increased at 2 and 6 h, and decreased at 9 h after LDM treatment. Enhanced protein expressions were parallel with respective increased mRNA level for Bax only, but not p53. Caspase inhibitor may inhibit partially the killing effects induced by LDM. Therefore we conclude that the rapid activation of mitochondrial pathway induced by LDM in tumor cells might contribute to its highly potent cytotoxicities.
Qiu
Qiang
Q
Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
Wang
Zhen
Z
Jiang
Jian-ming
JM
Li
Dian-dong
DD
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000617:Aminoglycosides / Q000494:pharmacology*; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000378:metabolism; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D053281:Enediynes / Q000494:pharmacology*; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000235:genetics; D051028:bcl-2-Associated X Protein / Q000096:biosynthesis / Q000235:genetics
D000590:Amino Acid Chloromethyl Ketones; D000617:Aminoglycosides; D000903:Antibiotics, Antineoplastic; D061945:Caspase Inhibitors; D053281:Enediynes; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C058024:C 1027; D045304:Cytochromes c; D020169:Caspases