A Ribosome-Inactivating Protein Principle from Hairy Roots and Seeds of Luffa cylindrica (L) Roem and its Cytotoxicity on Melanotic and Amelanotic Melanoma Cell Lines

Abstract

Single-chain ribosome-inactivating proteins (sc-RIP) are plant proteins that deadenylate ribosomal RNA at a specific site corresponding to A4324 of 28S r-RNA; they are therefore highly specific RNA N-glycosidases. RIPs have been studied as potential tumor cytotoxic agents, both in their native form and after conjugation with monoclonal antibodies. This study tested the sc-RIP extracts from the seeds and hairy root tissue cultures of Luffa cylindrica (established by transformation with Agrobacterium rhizogenes strain 1855) for inhibitory effects on the growth of in vitro melanotic and amelanotic human melanoma cell lines. Crude extracts from hairy roots and seeds inhibited protein synthesis in a reaction mixture containing an in vitro translation system based on rabbit reticulocyte lysate. Inhibitory activity increased during the hairy root culture period, reaching a maximum value in the stationary phase. Growth was inhibited in melanotic and amelanotic melanoma cells exposed to crude extracts from hairy roots and seeds of Luffa cylindrica for 24, 48 and 72 h.