Comparison of hexadecylphosphocholine with fish oil as an antitumor agent.

Hexadecylphosphocholine (HePC) reduced the growth of the human mammary tumor, MX-1, in the athymic nude mouse similar to the fish oil, MaxEPA. When used together, HePC and MaxEPA were additive towards reducing tumor growth. An unsaturated alkylphosphocholine mixture, ShisoPC, was not as effective as HePC in reducing tumor growth. MaxEPA reduced tumor PGE2 levels greater than 90%, while HePC and the ShisoPC only reduced tumor PGE2 40-60% with HePC being slightly better than ShisoPC. MaxEPA markedly increased the cellular omega 3 fatty acids and decreased 20:4 omega 6, the substrate for PGE2. HePC did not alter the tumor fatty acid composition, but it significantly lowered the total fatty acid concentration of the tumor by about 47%. In addition, phosphatidylcholine and sphingomyelin decreased in tumors from animals treated with HePC, and alterations in other phospholipids also were noted. These data suggest that different mechanisms exist for HePC and fish oil in reducing tumor growth.