Subamolide B Isolated from Medicinal Plant Cinnamomum subavenium Induces Cytotoxicity in Human Cutaneous Squamous Cell Carcinoma Cells through Mitochondrial and CHOP-Dependent Cell Death Pathways
Figure 4
Subamolide B activates the intrinsic (mitochondrial) apoptosis pathway. (a) Subamolide B dose-dependently downregulates BCL-2. SCC12 cells treated with subamolide B (0~20 μM) for 24 h were assessed for the levels of prosurvival BCL-2, BCL-xL, and proapoptotic BAX using immunoblot analysis. β-tubulin was used as the loading control. The density of each subamolide B-treated immunoblot signal was presented as the ratio to that of drug-untreated controls. (b) Subamolide B induces cytochrome c release to the cytosol. SCC12 cells treated with subamolide B (0~20 μM) for 24 h were fractionated into the mitochondrial and cytosolic fractions. The levels of cytochrome c in each fraction were then revealed by immunoblotting. The levels of COX-4 and β-tubulin were the loading controls for the mitochondrial and cytosolic fractions, respectively. Sub-B: subamolide B.
