Investigating the cytotoxic effects of the venom proteome of two species of theViperidaefamily (Cerastes cerastesandCryptelytrops purpureomaculatus) from various habitats

Animal secretions are of great interest in terms of drug development due to their complex protein and peptide composition. Especially, in the field of therapeutic medications such as anti-cancer drugs snake venoms receive attention. In this study we report of two Viperidae species from various habitats with a particular focus on the cytotoxic potential along with the decomplexation of the venom proteome: the horned desert viper ( Cerastes cerastes ), native to desert regions of North Africa and the mangrove pit viper (Cryptelytrops purpureomaculatus), found in coastal forests of Southeast Asia. Initial cytotoxic screenings of the crude venoms revealed diverse activity, with the highest effect against SHSY5Y human glioblastoma carcinoma cells compared to other cancerous and non-cancerous cell lines. In-depth cytotoxicity studies of SHSY5Y cells with purified venom fractions revealed dimeric disintegrins from C. cerastes venom which exerted a high cytotoxic activity with IC 50 values from 0.11 to 0.58µM and the disintegrins-like effect on SHSY5Y morphology was observed due to cell detachment. Furthermore, two polyproline BPP-related peptides, one PLA 2 and a peptide-rich fraction were determined for C. purpureomaculatus with moderate IC 50 values between 3-51µM. Additionally, the decryption of the venom proteomes by snake venomic mass spectrometry and comparison of same species from different habitats revealed slight differences in the composition.