Toxicity and structure-activity relationship (SAR) of α,β-dehydroamino acids against human cancer cell lines

Abstract A library of N -protected dehydroamino acids, namely dehydroalanine, dehydroaminobutyric acid and dehydrophenylalanine derivatives, was screened in three human cancer cell lines [(lung (A549), gastric (AGS) and neuroblastoma (SH-SY5Y)] in order to characterize their toxicological profile and identify new molecules with potential anticancer activity. Results showed N -protected dehydrophenylalanine and dehydroaminobutyric acid derivatives have no or low toxicity for all tested cell lines. The N -protected dehydroalanines exhibit significant toxic effects and the AGS and SH-SY5Y cells were significantly more vulnerable than A549 cells. Four α,β-dehydroalanine derivatives, with IC 50 50 concentrations, were able to induce apoptosis in both AGS and SH-SY5Y cell lines. In both cell lines, loss of mitochondrial membrane potential (ΔΨm) was found and caspase activity was increased, namely endoplasmic reticulum-resident caspase-4 in AGS cells and caspase-3/7 in SH-SY5Y cells. When evaluated in a non-cancer cell line, the molecules displayed no to low toxicity, thus suggesting some degree of selectivity for cancer cells. The results indicate that α,β-dehydroalanine derivatives can be considered a future resource of compounds able to work as anticancer drugs.