Polyunsaturated fatty acids (PUFAs) have tumoricidal action, though the exact mechanism of their action is not clear. The results of the present study showed that of all the
fatty acids tested,
linoleic acid (LA) and α-
linolenic acid (ALA) were the most effective in suppressing the growth of normal gastric cells (GES1) at 180 and 200 μM, while gastric
carcinoma cells (MGC and SGC) were inhibited at 200 μM.
Arachidonic acid (AA) suppressed the growth of GES1, MGC and SGC cells and lower concentrations (120 and 160 μM) of AA were more effective against gastric
carcinoma (MGC and SGC) cells compared to normal gastric cells (GES1). Paradoxically, both eicosapentaenoic (EPA) and docosahexaenoic (DHA)
acids though are more unsaturated than AA, were less effective compared with LA, ALA and AA in suppressing the growth of both normal and
cancer cells. At the concentration used,
methotrexate showed much less growth suppressive action compared to all the
fatty acids tested. PUFAs-treated cells showed accumulation of lipid droplets. A close association was noted between apoptosis and
lipid peroxides formed compared to the ability of normal and
tumor cells to generate ROS (
reactive oxygen species) and induce SOD (
superoxide dismutase activity) in response to
fatty acids tested and
methotrexate. Both normal and
tumor cells generated
lipoxin A4 (
LXA4) in response to supplementation of
fatty acids and
methotrexate though no significant correlation was noted between their ability to induce apoptosis and
LXA4 formed. These results suggest that PUFAs induced apoptosis of normal gastric and gastric
carcinoma cells could, partly, be attributed to lipid peroxidation process.