Sulphureuine B, a drimane type sesquiterpenoid isolated from Laetiporus sulphureus induces apoptosis in glioma cells

A drimane type sesquiterpenoids, sulphureuine B was isolated from the edible mushroom Laetiporus sulphureus and its antiproliferative properties were investigated using U-87MG glioma cells. It was observed that sulphureuine B-induced apoptosis in U-87MG cells and the mechanisms involved are endoplasmic reticulum stress, mitochondrial and death receptor mediated pathways. Endoplasmic reticulum stress was identified from the results of enormous cytoplasmic vacuolation, CHOP elevation and caspase-12 cleavage. Further, we found that treatment of sulphureuine B-induced PERK, IRE1 alpha, and ATF6 alpha activations. In addition, sulphureuine B-induced Bcl-2 downregulation, cleavage of PARP, and caspase-8 activation were also affected. All these experimental results clearly revealed that sulphureuine B-induced apoptosis mediated through endoplasmic reticulum stress, mitochondrial, and death receptor signaling pathways.