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 2
Apoptosis is partly responsible for subamolide B-induced SCC12 cell death. ((a), (b)) Subamolide B induces dose- and time-dependent proteolytic processing/activation of caspases-8, -9, -4, and -3. SCC12 cells were treated with subamolide B (0~20 μM) for 24 h (a) or treated with 20 μM of subamolide B for indicated length of time (b), followed by immunoblot analysis of caspase activation revealed by the status of proteolytic processing of PARP and procaspases-8, -9, -4, and -3. β-tubulin was used as the loading control. ((c), (d)) Caspase activities and hence apoptosis induction represent a mechanism of action of subamolide B-induced SCC12 cell death. Subamolide B (20 μM) was used to treat SCC12 cells for 24 h without or with cotreatment of the pan-caspase inhibitor z-VAD-fmk (20 μM). Cells were then revealed by Annexin-V/Propidium iodide (PI) double staining using flow cytometry analysis. The levels of apoptotic cells were indicated as the percentage of all cell populations as shown in (d). ***.
