Antiproliferative effect and apoptotic response in vitro of human melanomacells to liposomes containing the ribosome-inactivating protein luffin

The present study describes the liposome-mediated delivery of the type 1 ri bosome-inactivating protein luffin to human melanoma cells in vitro. Luffin from Luffa cylindrica seeds has been successfully incorporated into lecith in/cholesterol and lecithin/cholesterol/dicetylphosphate negatively charged liposomes. The exposure of melanoma cells to the two types of liposomes re sulted in the inhibition of protein synthesis and cell growth; apoptotic ce ll death was verified by means of TUNEL reaction and quantitation of cytoso lic oligonucleosome-bound DNA. The toxicity of encapsulated luffin varied w ith the lipid composition of the vesicles; the strongest effect was observe d with lecithin/cholesterol liposomes. These results identify liposome-inco rporated luffin as a possible alternative to immunotoxins for the treatment of human melanoma in situ. (C) 1999 Elsevier Science B.V. All rights reser ved.