A mixture of trans, trans conjugated linoleic acid induces apoptosis in MCF-7 human breast cancer cells with reciprocal expression of Bax and Bcl-2.
The growth inhibitory effect of a mixture of trans, trans conjugated linoleic acid isomers (t, t CLA) was investigated in a human breast cancer cell line, MCF-7, with references to c9, t11 CLA, t10, c12 CLA, and linoleic acid. The t, t CLA treatment effectively induced a cytotoxic effect in a time-dependent (0-6 days) and concentration-dependent (0-40 microM) manner, as compared to the reference and control treatments. The apoptotic parameters were measured on cells treated with 40 microM t, t CLA for 4 days. The occurrence of the characteristic morphological changes and DNA fragmentation confirmed apoptosis. The t, t CLA treatment led to an increase in the level of p53 tumor suppressor protein and Bax protein, but suppressed the expression of Bcl-2 protein. In addition, cytochrome c was released from the mitochondria into the cytosol, and the activation of caspase-3 led to the cleavage of poly(ADP-ribose) polymerase (PARP). Moreover, the composition of the linoleic and arachidonic acids was decreased in cellular membranes. These findings suggest that incorporation of t, t CLA in the membrane induces a mitochondria-mediated apoptosis that can enhance the antiproliferative effect of t, t CLA in MCF-7 cells.
Division of Applied Life Sciences (BK21), Graduate School, Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 660-701, Republic of Korea.
Mohammad A
MA
Islam
Young S
YS
Kim
Wook J
WJ
Jang
Seon M
SM
Lee
Hoon G
HG
Kim
So Y
SY
Kim
Jeong O
JO
Kim
Yeong L
YL
Ha
D017209:Apoptosis / Q000187:drug effects*; D001943:Breast Neoplasms; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000378:metabolism; D053938:DNA Fragmentation; D006801:Humans; D044243:Linoleic Acids, Conjugated / Q000494:pharmacology*; D008928:Mitochondria / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis*; D051028:bcl-2-Associated X Protein / Q000032:analysis*
D044243:Linoleic Acids, Conjugated; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D045304:Cytochromes c