title: 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.
abstract: Subamolide B is a butanolide isolated from Cinnamomum subavenium, a medicinal plant traditionally used to treat various ailments including carcinomatous swelling. We herein reported for the first time that subamolide B potently induced cytotoxicity against diverse human skin cancer cell lines while sparing nonmalignant cells. Mechanistic studies on human cutaneous squamous cell carcinoma (SCC) cell line SCC12 highlighted the involvement of apoptosis in subamolide B-induced cytotoxicity, as evidenced by the activation of caspases-8, -9, -4, and -3, the increase in annexin V-positive population, and the partial restoration of cell viability by cotreatment with the pan-caspase inhibitor z-VAD-fmk. Additionally, subamolide B evoked cell death pathways mediated by FasL/Fas, mitochondria, and endoplasmic reticulum (ER) stress, as supported by subamolide B-induced FasL upregulation, BCL-2 suppression/cytosolic release of cytochrome c, and UPR activation/CHOP upregulation, respectively. Noteworthy, ectopic expression of c-FLIPL or dominant-negative mutant of FADD failed to impair subamolide B-induced cytotoxicity, whereas BCL-2 overexpression or CHOP depletion greatly rescued subamolide B-stimulated cells. Collectively, these results underscored the central role of mitochondrial and CHOP-mediated cell death pathways in subamolide B-induced cytotoxicity. Our findings further implicate the potential of subamolide B for cutaneous SCC therapy or as a lead compound for developing novel chemotherapeutic agents.
authors.affiliation: Institute of Biomedical Sciences, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40227, Taiwan.
authors.forename: Shu-Yi
authors.initials: SY
authors.lastname: Yang
authors.forename: Hui-Min
authors.initials: HM
authors.lastname: Wang
authors.forename: Tai-Wen
authors.initials: TW
authors.lastname: Wu
authors.forename: Yi-Ju
authors.initials: YJ
authors.lastname: Chen
authors.forename: Jeng-Jer
authors.initials: JJ
authors.lastname: Shieh
authors.forename: Ju-Hwa
authors.initials: JH
authors.lastname: Lin
authors.forename: Tsing-Fen
authors.initials: TF
authors.lastname: Ho
authors.forename: Ren-Jie
authors.initials: RJ
authors.lastname: Luo
authors.forename: Chung-Yi
authors.initials: CY
authors.lastname: Chen
authors.forename: Chia-Che
authors.initials: CC
authors.lastname: Chang