Cyclamin, a Natural 13,28-Epoxy Triterpenoid Saponin, Synergistically Enhances the Cytotoxicity of Chemotherapeutic Drugs in Human Liver Cancer Cells but Not Non-Neoplastic Liver Cells

Abstract

In this study, a diverse set of triterpenoid saponins was evaluated to assess their chemosensitizing activity in two human liver cancer cells (Bel-7402 and HepG2) and non-neoplastic HL-7702 liver cells. Cyclamin, a 13,28-epoxy oleanane-type triterpenoid saponin from Ardisia japonica, was identified as a potent chemosensitizer. A low cytotoxic level of cyclamin synergistically enhances the growth inhibitory effect of 5-fluorouracil (from 41.3 ± 1.1 % to 64.5 ± 2.3 %), cisplatin (from 57.1 ± 1.5 % to 79.6 ± 2.7 %), and epirubicin (from 62.6 ± 1.2 % to 74.9 ± 1.8 %) on Bel-7402 cells, but not HL-7702 cells. Flow cytometric analysis shows that cyclamin synergistically enhances the apoptosis and cell cycle arrest induction effects of 5-fluorouracil by 69.4 % and 22.2 %, respectively. The mechanism of action could be through the activation of caspase-3, -8, and -9, the upregulation of cyclin-dependent kinase 2, the cell division cycle 25 homolog A expression level, or the Bax/B-cell lymphoma 2 ratio. Furthermore, a lactate dehydrogenase release assay demonstrated that cyclamin markedly increases the membrane permeability of Bel-7402 cells, which may also contribute to the mechanism of the chemosensitizing activity of cyclamin. These findings indicate the potential usefulness of cyclamin for the chemoprevention and treatment of liver cancer.

Key words

Ardisia japonica - Myrsinaceae - cyclamin - chemosensitizer - liver cancer - permeability - cytotoxicity

• References

• 1 Jemal A, Bray F, Center MM, Ferlay J, Ward E, Forman D. Global cancer statistics. CA Cancer J Clin 2011; 61: 69-90
• 2 Rahbari NN, Mehrabi A, Mollberg NM, Muller SA, Koch M, Büchler MW, Weitz J. Hepatocellular carcinoma: current management and perspectives for the future. Ann Surg 2011; 253: 453-469
• 3 Sarkar FH, Li Y. Using chemopreventive agents to enhance the efficacy of cancer therapy. Cancer Res 2006; 66: 3347-3350
• 4 Dorai T, Aggarwal BB. Role of chemopreventive agents in cancer therapy. Cancer Lett 2004; 215: 129-140
• 5 Caliş T, Satana ME, Yürüker A, Kelican P, Demirdamar R, Alaçam R, Tanker N, Rüegger H, Sticher O. Triterpene saponins from Cyclamen mirabile and their biological activities. J Nat Prod 1997; 60: 315-318
• 6 Liu DL, Wang NL, Zhang X, Gao H, Yao XS. Two new triterpenoid saponins from Ardisia crenata . J Asian Nat Prod Res 2007; 9: 119-127
• 7 Foubert K, Theunis M, Apers S, Vlietinck AJ, Pieters L. Chemistry, distribution and biological activities of 13, 28-epoxy-oleanane saponins from the plant families Myrsinaceae and Primulaceae. Curr Org Chem 2008; 12: 629-642
• 8 Chang X, Li W, Jia Z, Satou T, Fushiya S, Koike K. Biologically active triterpenoid saponins from Ardisia japonica . J Nat Prod 2007; 70: 179-187
• 9 Liang D, Hao ZY, Zhang GJ, Zhang QJ, Chen RY, Yu DQ. Cytotoxic triterpenoid saponins from Lysimachia clethroides . J Nat Prod 2010; 74: 2128-2136
• 10 Mu LH, Huang CL, Zhou WB, Guo DH, Liu P. Methanolysis of triterpenoid saponin from Ardisia gigantifolia Stapf. and structure-activity relationship study against cancer cells. Bioorg Med Chem Lett 2013; 23: 6073-6078
• 11 Zhang CX, Zhang DM, Chen MF, Guan SY, Yao JH, He XX, Lei LF, Zhong Y, Wang ZF, Ye WC. Antiproliferative triterpenoid saponins from the stem of Psychotria sp. Planta Med 2013; 79: 978-986
• 12 Li Q, Li W, Hui LP, Zhao CY, He L, Koike K. 13, 28-Epoxy triterpenoid saponins from Ardisia japonica selectively inhibit proliferation of liver cancer cells without affecting normal liver cells. Bioorg Med Chem Lett 2012; 22: 6120-6125
• 13 Chou TC, Talalay P. Quantitative analysis of dose-effect relationships: the combined effects of multiple drugs or enzyme inhibitors. Adv Enzyme Regul 1984; 22: 27-55
• 14 Green DR. Apoptotic pathways: paper wraps stone blunts scissors. Cell 2000; 102: 1-4
• 15 Ming ZJ, Hua Y, Qiu YH, Cao L, Zhang XG. Synergistic effects of β-aescin and 5-fluorouracil in human hepatocellular carcinoma SMMC-7721 cells. Phytomedicine 2010; 17: 575-580
• 16 Sandhu C, Donovan J, Bhattacharya N, Stampfer M, Worland P, Slingerland J. Reduction of Cdc25A contributes to cyclin E1-Cdk2 inhibition at senescence in human mammary epithelial cells. Oncogene 2000; 19: 5314-5323
• 17 Seeman P, Cheng D, Iles GH. Structure of membrane holes in osmotic and saponin hemolysis. J Cell Biol 1973; 56: 519-527
• 18 Seeman P. Ultrastructure of membrane lesions in immune lysis, osmotic lysis and drug-induced lysis. Fed Proc 1974; 33: 2116-2124
• 19 Gaidi G, Correia M, Chauffert B, Beltramo JL, Wagner H, Lacaille-Dubois MA. Saponins-mediated potentiation of cisplatin accumulation and cytotoxicity in human colon cancer cells. Planta Med 2002; 68: 70-72
• 20 Francis G, Kerem Z, Makkar HP, Becker K. The biological action of saponins in animal systems: a review. Br J Nutr 2002; 88: 587-605
• 21 Bachran C, Sutherland M, Heisler I, Hebestreit P, Melzig MF, Fuchs H. The saponin-mediated enhanced uptake of targeted saporin-based drugs is strongly dependent on the saponin structure. Exp Biol Med 2006; 231: 412-420