Extract of the sea cucumber, Holothuria scabra, induces apoptosis in human glioblastoma cell lines

Abstract

Background: Glioblastoma is the most aggressive primary brain tumor resistant to conventional treatment, and has a frequent recurrence. Holothuria scabra is the most widely consumed sea cucumber in Thailand and Asian countries. Sea cucumber extracts have valuable bioactive ingredients that are utilized in Chinese traditional medicine for several therapeutic measures including anti-cancer. In this study, we aimed to test the anticancer activity of H. scabra body wall extract in ethyl acetate fraction against two human glioblastoma cell lines A172 and U87MG.

Material and methods: The anticancer effect of the ethyl acetate fraction of body wall extracts from H. scabra (HSBWEA) was tested against two human glioblastoma cell lines A172 and U87MG to determine cell viability, apoptotic cell analysis, mitochondrial membrane potentials, nuclear condensation and expression of apoptotic molecules. The bioactive compound in the extract was characterized by LC-MS/MS.

Results: The extract exhibited strong cytotoxic effect to A172 and U87MG cells with IC50 4.23 and 4.46 mg/ml, respectively. The extract also induced both early and late stages of apoptosis, loss of mitochondrial membrane potentials and nuclear condensation and fragmentation. After treatment with the extract for 24 h, the cells expressed increasing amounts of a pro-apoptotic Bax and caspase-3 while an anti-apoptotic Bcl-2 was decreased in a concentration-dependent manner. The major bioactive components in this extract are triterpene glycosides similar to those described previously in H. scabra as well as in other related sea cucumber species.

Conclusions: The crude extract from the body wall of H. scabra exhibited anticancer activity against human glioblastoma cells through the mitochondrial-mediated apoptotic pathway, and the compounds in the extract might be a novel candidate for anti-glioblastoma.