Honokiol-induced apoptosis and autophagy in glioblastoma multiforme cells

Honokiol, a hydroxylated biphenyl compound isolated from the Chinese herb Magnolia officinalis, has been reported to have Anticancer activities in a variety of Cancer cell lines. The present study aimed to evaluate the Anticancer effect and possible molecular mechanisms of honokiol in a glioblastoma multiforme (GBM) cell line. The Anticancer activities of honokiol were investigated in the DBTRG-05MG GBM cell line. The effect of honokiol on cell growth was determined using a sulforhodamine B assay. Flow cytometry and immunoblotting were used to measure honokiol-induced Apoptosis (programmed cell death type I) and Autophagy (programmed cell death type II). Honokiol was observed to reduce DBTRG-05MG cell viability in a dose-dependent manner. At a dose of 50 μM, honokiol markedly decreased the expression of Rb protein and led to the cleavage of poly(ADP-ribose) polymerase and Bcl-xL to promote Apoptosis in the Cancer cells. In addition, markers of Autophagy, including Beclin-1 and LC3-II, were also significantly increased. In addition to Apoptosis, honokiol was also able to induce Autophagy in the DBTRG-05MG cells. The mechanisms that are responsible for the correlation between honokiol-induced Apoptosis and Autophagy require further investigation. Such efforts may provide a potential strategy for improving the clinical outcome of GBM treatment.