Previous studies showed that gamma-linolenic acid (GLA, 18: 3 omega-6), arachidonic acid (AA, 20:4 omega -6), eicosapentaenoic acid (EPA, 20: 5 omega -3) and docosahexaenoic acid (DHA, 22:6 omega -3) have selective tumoricidal action. In the present study, it was observed that dihomo-gamma-linolenic acid (DGLA) and AA, EPA and DHA have cytotoxic action on both vincristine-sensitive (KB-3-1) and resistant (KB-ChR-8-5) cancer cells in vitro that appeared to be a free-radical dependent process but not due to the formation of prostaglandins, leukotrienes and thromboxanes.

Uptake of vincristine and fatty acids was higher while their efflux was lower in KB-3-1 cells compared with KB-ChR-8-5 cells, suggesting that drug resistant cells have an effective efflux pump. GLA, DGLA, AA, EPA and DHA enhanced the uptake and decreased efflux in both drug-sensitive and drug-resistant cells and augmented the susceptibility of tumor cells especially, of drug-resistant cells to the cytotoxic action of vincristine.

These results suggest that certain polyunsaturated fatty acids have tumoricidal action and are capable of enhancing the cytotoxic action of anti-cancer drugs specifically, on drug-resistant cells by enhancing drug uptake and reducing its efflux.

Thus, polyunsaturated fatty acids either by themselves or in combination with chemotherapeutic drugs have the potential as anti-cancer molecules.

PMID: 21917129

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