N-acyl taurines are anti-proliferative in prostate cancer cells

Endocannabinoids have been implicated in cancer development and cause heterogenous effects in tumor cells, by inducing apoptosis, reducing migration, causing anti-angiogenic activity and alterations in the cell cycle resulting in growth arrest. Recently, several novel amides of fatty acids that are structurally related to endocannabinoids have been isolated from mammalian sources, although the functions of these fatty amides are not well studied. One group of these novel fatty acid amides are the N-acyl taurines (fatty acids conjugated to the amino acid taurine). This study examined if N-acyl taurines, specifically N-arachidonoyl taurine and N-oleoyl taurine could function in a similar way to endocannabinoids and result in cell cycle alterations or growth arrest in the human prostate adenocarcinoma cell line PC-3. PC-3 cells were treated with various concentrations of N-arachidonoyl taurine and N-oleoyl taurine and cell proliferation and viability was measured using resazurin and colony formation assays. Effects of N-acyl taurines on the cell cycle was measured using FACS analysis. Treatment with N-arachidonoyl taurine and N-oleoyl taurine resulted in a significant reduction in proliferation of PC-3 cells, even at concentrations as low as 1 μM. Treatment with N-oleoyl taurine resulted in an increased number of cells in the subG1 population, suggesting apoptosis, and a lower number of cells in S-phase of the cell cycle. In summary, our results show that novel biologically active lipids, the N-acyl taurines, result in reduced proliferation in PC-3 cells.