smenospongine and Multiple-Myeloma

Abnormal up-regulation of β-catenin expression is associated with the development and progression of multiple myeloma and is thus a potential therapeutic target. Here, we screened cell-based natural compounds and identified smenospongidine, a metabolite isolated from a marine sponge, as an antagonist of the Wnt/β-catenin signaling pathway. Smenospongidine promoted the degradation of intracellular β-catenin that accumulated via Wnt3a or 6-bromoindirubin-3'-oxime, an inhibitor of glycogen synthase kinase-3β. Consistently, smenospongidine down-regulated β-catenin expression and repressed the levels of β-catenin/T cell factor-dependent genes such as axin2, c-myc, and cyclin D1 in RPMI-8226 multiple myeloma cells. Smenospongidine suppressed proliferation and significantly induced apoptosis in RPMI-8266 cells. In addition, smenospongidine-induced β-catenin degradation was mediated by up-regulating CCAAT/enhancer-binding protein homologous protein (CHOP). These findings indicate that smenospongidine exerts its anti-proliferative activity by blocking the Wnt/β-catenin signaling pathway and may be a potential chemotherapeutic agent against multiple myeloma.

Topics: Animals; Antineoplastic Agents; Apoptosis; beta Catenin; CCAAT-Enhancer-Binding Protein-beta; Cell Proliferation; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Humans; Molecular Structure; Multiple Myeloma; Porifera; Quinones; Sesquiterpenes; Structure-Activity Relationship; Tumor Cells, Cultured