Isocostunolide inhibited glioma stem cell by suppression proliferation and inducing caspase dependent apoptosis

Glioblastoma multiform (GBM) is a highly aggressive brain tumor with poor life expectancy, and glioma stem cells (GSCs) are a small population of tumor cells existed in GBM, in which GSCs response to drive GBM recurrence, invasion and contribute to the anti-cancer resistance. GSCs have been identified and developed as a therapeutic target for GBM and can be used in drugs screening. Isocostunolide is a natural sesquiterpenoid and contained abundant resource in medicinal plants, but the anti-cancer efficacies of it against GSCs are still unexplored. In this investigation, the anti-tumor activity of isocostunolide against GSCs was investigated and the result demonstrated that it inhibited the growth of GSCs (GSC-3#, GSC-12#, GSC-18#) significantly with an IC₅₀ value of 2.80μg/ml, 2.61μg/ml, 1.07μg/ml, respectively. In further mechanism study, isocostunolide inhibited GSCs cell proliferation, induced GSCs apoptosis significantly, as well as increased the proportion of the cleavage of caspase-3. The result suggested that isocostunolide induced GSCs apoptosis via the caspase dependent apoptotic pathway. Moreover, isocostunolide damaged GSCs colony formation capacity significantly and exhibited the anti-cancer efficacy against GSCs in vitro.