timosaponin-aiii and Liver-Neoplasms

As high cholesterol level has been reported to be associated with cancer cell growth and cholesterol is vulnerable to oxidation, the conventional liposomes including cholesterol in the formulation seem to be challenged. Timosaponin AIII (TAIII), as a steroid saponin from. The synergistic effects of DOX and TAIII were explored on HCC cells and the tumor inhibition rate of TAIII-based liposomes carrying DOX was evaluated on both subcutaneous and orthotopic transplantation tumor models. TAIII-based multifunctional liposomes were characterized.. Synergistic HCC cytotoxicity was achieved at molar ratios of 1:1, 1:2 and 1:4 of DOX/TAIII. TAIII-based liposomes carrying a low DOX dose of 2 mg/kg exhibited significantly enhanced antitumor activity than 5 mg/kg of DOX without detected cardiotoxicity on both subcutaneous and orthotopic transplantation tumor models. TAIII-based liposomes were characterized with smaller size than cholesterol liposomes but exhibited favorable stability. Mild hyperthermia generated by laser irradiation accelerated the release of DOX and TAIII from liposomes at tumor site, and cell permeability of TAIII enhanced uptake of DOX in HCC cells.. The innovative application of TAIII working as bilayer stabilizer and chemotherapeutic drug affords a stable multifunctional liposomal delivery system for synergistic therapy against HCC, which may be referred for the development of other types of saponins with similar property.

Topics: Carcinoma, Hepatocellular; Cell Line, Tumor; Humans; Liposomes; Liver Neoplasms; Saponins; Steroids

Timosaponin A-III (TSA-III), a saponin isolated from the rhizome of Anemarrhena asphodeloides, exhibits potent cytotoxicity and has the potential to be developed as an anticancer agent. However, the molecular mechanism underlying the anticancer activity of TSA-III has not been fully elucidated. In this study, the apoptotic effects of TSA-III were investigated in HepG2 cells. Treatment with TSA-III significantly inhibited cell growth in a concentration- and time-dependent manner by inducing apoptosis in HepG2 cells. This induction was associated with increased fluorescence intensity of Annexin V-FITC, activation of caspases, and altered expression of inhibitor of apoptosis protein (IAP) family members. In addition, TSA-III mediated mitochondrial dysfunction with the release of HtrA2/Omi, Smac/Diablo, and cytochrome c. These findings suggest that TSA-III induces mitochondria-mediated and caspase-dependent apoptosis in HepG2 cells by altering expression of the IAP family. Thus, TSA-III could possibly be used to treat other types of cancer with similar pathologic mechanisms.

Topics: Anemarrhena; Antineoplastic Agents, Phytogenic; Apoptosis; Apoptosis Regulatory Proteins; Carcinoma, Hepatocellular; Caspases; Cell Culture Techniques; Cell Differentiation; Cell Proliferation; Cell Survival; Cytochromes c; Cytosol; Dose-Response Relationship, Drug; Hep G2 Cells; Humans; Liver Neoplasms; Mitochondria, Liver; Protein Transport; Rhizome; Saponins; Steroids

Inducing tumor cell death is one of the major therapeutic strategies in treating cancer. The aim of this study is to investigate the mechanism underlying the involvement of autophagy in cell death induced by timosaponin AIII (TAIII). Cell viability was determined by MTT and cologenic assay; apoptosis was determined by flow cytometry and TUNEL assay; autophagy was examined by immunoblotting and immunofluorescence; ubiquitination was detected by co-immunoprecipitation; mRNA expression was detected by real-time PCR; and determination of necrotic cell death was approached with LDH assay. The in vivo tumor growth inhibition was determined by xenograft model. TAIII exhibits potent cytotoxicity on human hepatocellular carcinoma (HCC) cells without severe hepatic toxicity. TAIII induced caspase-dependent apoptosis in HCC, and the induction of apoptosis was attributed to the inhibition of TAIII on XIAP expression. Repressing XIAP expression allowed cell tolerance toward the treatment with TAIII. The suppression of XIAP by TAIII is under post-transcriptional control and independent of proteasomal-driven proteolysis. Instead, TAIII-induced AMPKα/mTOR-dependent autophagy was responsible for XIAP suppression and triggered the XIAP heading lysosomal degradation pathway. Ubiquitination of IAPs is required for the autophagic degradation induced by TAIII. Blockade of autophagy turns on the switch of necrotic cell death in TAIII-treated cells. Timosaponin AIII induces HCC cell apoptosis through a p53-independent mechanism involving XIAP degradation through autophagy-lysosomal pathway. The possibility of developing TAIII as a new anti-tumor agent is worth considering.

Topics: AMP-Activated Protein Kinases; Animals; Apoptosis; Autophagy; Carcinoma, Hepatocellular; Caspases; Cell Proliferation; Enzyme Activation; Hep G2 Cells; Humans; Liver Neoplasms; Mice; Necrosis; Proteolysis; Saponins; Steroids; Ubiquitination; X-Linked Inhibitor of Apoptosis Protein