Five-lipoxygenase-activating protein inhibitor MK-886 induces apoptosis in gastric cancer through upregulation of p27kip1 and bax.
OBJECTIVE
Products of the arachidonic acid metabolizing enzyme, 5-lipoxygenase (5-LOX), stimulate the growth of several cancer types. Inhibitors of 5-LOX and 5-LOX-activating protein (FLAP) induce apoptosis in some cancer cells. Here, the authors investigated the effect of a FLAP inhibitor, MK-886, on the inhibition of proliferation and induction of apoptosis in gastric cancer.


METHODS
Cell proliferation in gastric cancer cells was measured using an 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide assay. Apoptosis was measured using acridine orange staining and flow cytometry. Protein expression of apoptosis-related genes p53, p21waf1, p27kip1, bcl-2 families, cytochrome c, and the caspases were examined using Western blotting. Caspase-3 activity was measured using colorimetric assay of substrate cleavage.


RESULTS
MK-886 inhibited cell growth in a dose- and time-dependent manner. Apoptosis was induced in gastric cancer cells and was characterized by upregulation of p27kip1 and bax, with release of cytochrome c from mitochondria into cytosol, which initiated caspase-3 activation. Specific caspase-3 inhibitors partially blocked MK-886-induced apoptosis.


CONCLUSIONS
The present results suggest that MK-886 induces apoptosis in gastric cancer cells through upregulation of p27kip1 and bax, and that MK-886 is a potentially useful drug in gastric cancer prevention and therapy.
Fan
Xiao Ming
XM
Department of Medicine, Fudan University Affiliated Jinshan Hospital, Shanghai, China.
Tu
Shui Ping
SP
Lam
Shiu Kum
SK
Wang
Wei Ping
WP
Wu
Jing
J
Wong
Wai Man
WM
Yuen
Man Fung
MF
Lin
Marie Chia Mi
MC
Kung
Hsiange Fu
HF
Wong
Benjamin Chun-Yu
BC
D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000378:metabolism*; D050760:Cyclin-Dependent Kinase Inhibitor p27; D045304:Cytochromes c / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2; D013274:Stomach Neoplasms / Q000276:immunology*; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D015854:Up-Regulation; D051028:bcl-2-Associated X Protein; D002722:Chlorobenzenes
D020169:Caspases; D018797:Cell Cycle Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D045304:Cytochromes c; D007211:Indoles; D016859:Lipoxygenase Inhibitors; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D025521:Tumor Suppressor Proteins; D051028:bcl-2-Associated X Protein; C494826:BAX protein, human; C060893:MK-886; D002722:Chlorobenzenes