Linoleic Acid-Induced Growth Inhibition of Human Gastric Epithelial Adenocarcinoma AGS Cells is Associated with Down-Regulation of Prostaglandin E2 Synthesis and Telomerase Activity

BACKGROUND Linoleic acid is the most abundant polyunsaturated fatty acid in human nutrition and found in most vegetable oils and certain food products. In the present study, we investigated the effects of linoleic acid on the growth of human epithelial adenocarcinoma AGS cells. METHODS MTT assay, flow cytometry, RT-PCR and Western-blot analyses were used to investigate the effects and underlying mechanisms of linoleic acid on AGS cells. The effects of this compound were also tested on prostaglandin E2 (PGE2) production and telomerase activity. RESULTS Our data indicated that growth inhibition of AGS cells by linoleic acid treatment was associated with induction of apoptosis. Linoleic acid treatment decreased the expression levels of the cyclooxygenase (COX)-2 mRNA and protein without causing significant changes in the COX-1 levels, which was correlated with the inhibition of PGE2 synthesis. Linoleic acid treatment also decreased the expression of human telomerase reverse transcriptase (hTERT), a main determinant of the telomerase enzymatic activity, and activity of telomerase, with inhibiting the expression of c-myc in a concentration-dependent manner. CONCLUSIONS Taken together, our results indicate that linoleic acid inhibits the production of PGE2 and activity of telomerase by suppressing COX-2 and hTERT expression.