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Growth Inhibition of Osteosarcoma Cell MG‐63 by a Mixture of trans,trans Conjugated Linoleic Acid Isomers: Possible Mechanistic Actions
Author(s) -
Kim Y.S.,
Cerbo R.M.,
Hah C.K.,
Bahn K.N.,
Kim J.O.,
Ha Y.L.
Publication year - 2007
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1750-3841.2007.00584.x
Subject(s) - apoptosis , conjugated linoleic acid , dna fragmentation , cell cycle , cytochrome c , linoleic acid , cell growth , chemistry , cytotoxic t cell , arachidonic acid , poly adp ribose polymerase , microbiology and biotechnology , biology , biochemistry , dna , programmed cell death , enzyme , polymerase , fatty acid , in vitro
The growth inhibitory effect of a mixture of t,t conjugated linoleic acid isomers ( t,t CLA) was investigated in the human osteosarcoma cell MG‐63, with references to c 9, t 11 and t 10, c 12 CLA isomers. The t,t CLA effectively induced a cytotoxic effect in a time‐dependent (0 to 6 d) and concentration‐dependent (0 to 40 μM) manner, as compared to the reference and control treatments. The apoptosis and cell cycle related parameters were measured on the cells treated with 40 μM t,t CLA for 4 d. Flow cytometric analysis revealed that the t,t CLA treatment effectively increased the proportion of apoptotic cells with a low DNA content (sub G0/G1) and a marked loss of cells from the G0/G1 phase of the cell cycle, relative to other treatments. The occurrence of the characteristic morphological changes and DNA fragmentation confirmed the apoptosis. The level of Bax protein was increased, whereas the Bcl‐2 expression was reduced. 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 linoleic and arachidonic acids in membrane was decreased by increase in t,t CLA. These findings suggest that t,t CLA incorporation in membrane activates a mitochondria‐mediated apoptosis pathway that can enhance the antiproliferative effect of t,t CLA in the osteosarcoma cells.