Tubeimoside I

Tubeimoside I(Lobatoside-H) is an extract from Chinese herbal medicine Bolbostemma paniculatum (MAXIM.) FRANQUET (Cucurbitaceae) has been shown as a potent anti-tumor agent for a variety of human cancers. IC50 value: Target: Anticancer natural compound in vitro: TBMS I inhibited the proliferation of both HepG2 and L-02 cells in a dose- and time-dependent manner, but HepG2 cells appeared more sensitive to the agent. When exposed to TBMS I for 24, 48 and 72 h, IC50 for HepG2 cells versus L-02 cells were 15.5 vs. 23.1, 11.7 vs. 16.2, 9.2 vs. 13.1 (μM, p<0.01), respectively. TBMS I induced cell shrinkage, nuclear condensation and fragmentation, cell cycle arrest at the G2/M phase, mitochondrial membrane disruption, release of cytochrome c from the mitochondria, activation of caspase 3 and 9, and shifting Bax/Bcl-2 ratio from being anti-apoptotic to pro-apoptotic, all indicative of initiation and progression of apoptosis involving mitochondrial dysfunction [1]. TBMS1-induced molecular events were related to mitochondria-induced intrinsic apoptosis and P21-cyclin B1/cdc2 complex-related G2/M cell cycle arrest [2]. TBMS1 combined with CDDP promoted cell apoptosis, decreased proliferation activity and increased cytosolic Ca2+ levels. Bcl-2 protein expression was down-regulated but Bax was up-regulated. Moreover, GST-π mRNA and protein expression were decreased. TBMS1 reduced the resistance of the cells to CDDP-induced cytotoxicity [4]. Treatment with TBMS1 resulted in dose- and time-dependent inhibition of proliferation, led to arrest in phase G2/M of the cell cycle and increased the levels of intracellular Ca2?. Furthermore, TBMS1 up-regulated the levels of the glucose-regulated protein 78/immunoglobuin heavy chain binding protein (GRP78/Bip), C/EBP homologous protein (CHOP), Bax, and cleaved caspase-3 and down-regulated the levels of Bcl-2 [5]. in vivo: TBMS1 significantly inhibited the production of the pro-inflammatory cytokines, TNF-α, IL-6 and IL-1β in vitro and in vivo. Pretreatment with TBMS1 markedly attenuated the development of pulmonary edema, histological severities and inflammatory cells infiltration in mice with ALI [3].

References:
[1]. Wang Y, et al. Natural plant extract tubeimoside I promotes apoptosis-mediated cell death in cultured human hepatoma (HepG2) cells. Biol Pharm Bull. 2011;34(6):831-8. [2]. Xu Y, et al. Intrinsic apoptotic pathway and G2/M cell cycle arrest involved in tubeimoside I-induced EC109 cell death. Chin J Cancer Res. 2013 Jun;25(3):312-21. [3]. Wu Q, et al. Tubeimoside-1 attenuates LPS-induced inflammation in RAW 264.7 macrophages and mouse models. Immunopharmacol Immunotoxicol. 2013 Aug;35(4):514-23. [4]. Liu HZ, et al. Tubeimoside I sensitizes cisplatin in cisplatin-resistant human ovarian cancer cells (A2780/DDP) through down-regulation of ERK and up-regulation of p38 signaling pathways. Mol Med Rep. 2011 Sep-Oct;4(5):985-92. [5]. Chen WJ, et al. Tubeimoside-1 induces G2/M phase arrest and apoptosis in SKOV-3 cells through increase of intracellular Ca2+ and caspase-dependent signaling pathways. Int J Oncol. 2012 Feb;40(2):535-43.

Role of mitochondria and mitochondrial cytochrome c in tubeimoside I-mediated apoptosis of human cervical carcinoma HeLa cell line.[Pubmed:16172906]

Cancer Chemother Pharmacol. 2006 Feb;57(3):389-99.

BACKGROUND: Tubeimoside I (TBMS1), a triterpenoid saponin, isolated from the tubers of Bolbostemma paniculatum, showed potent antitumor and antitumor-promoting effects. The objective of this study is to investigate the role of mitochondria and mitochondria cytochrome c in TBMS1-mediated apoptosis of human cervical carcinoma HeLa cell line. METHODS: Viability of HeLa cells was measured by MTT assay. Apoptotic induction by TBMS1 was determined by fluorescence microscopy, flow cytometry and gel electrophoresis of fragmented DNA. Mitochondrial transmembrane potential (Deltapsim) was assayed by flow cytometry. Cytochrome c (Cyt c) was detected by Western blotting. RESULTS: The results showed that Cyclosporin A (CsA) partly protected HeLa cells from growth inhibitory effect of TBMS1, and partly countered the ability of TBMS1 to rapidly induce apoptosis in HeLa cells, and that TBMS1 decreased Deltapsim and induced Cyt c release by a mechanism inhibited by CsA, and that TBMS1 induced apoptosis of HeLa cells dose-dependently in accordance with increase of cytosolic Cyt c. CONCLUSIONS: TBMS1 opens the permeability transition (PT) pore, thereby decreasing Deltapsim, releasing Cyt c from mitochondria, and further causing a series of events consistent with established mechanistic models of apoptosis.

Intrinsic apoptotic pathway and G2/M cell cycle arrest involved in tubeimoside I-induced EC109 cell death.[Pubmed:23825908]

Chin J Cancer Res. 2013 Jun;25(3):312-21.

OBJECTIVE: Squamous esophageal carcinoma is highly prevalent in developing countries, especially in China. Tu Bei Mu (TBM), a traditional folk medicine, has been used to treat esophageal squamous cell carcinoma (ESCC) for a long term. Tubeimoside I (TBMS1) is the main component of TBM, exhibiting great anticancer potential. In this study, we investigated the mechanism of TBMS1 cytotoxic effect on EC109 cells. METHODS: Comparative nuclear proteomic approach was applied in the current study and we identified several altered protein spots. Further biochemical studies were carried out to detect the mitochondrial membrane potential, cell cycle and corresponding proteins' expression and location. RESULTS: Subcellular proteomic study in the nucleus from EC109 cells revealed that altered proteins were associated with mitochondrial function and cell proliferation. Further biochemical studies showed that TBMS1-induced molecular events were related to mitochondria-induced intrinsic apoptosis and P21-cyclin B1/cdc2 complex-related G2/M cell cycle arrest. CONCLUSIONS: Considering the conventional application of TBM in esophageal cancer, TBMS1 therefore may have a great potential as a chemotherapeutic drug candidate for ESCC.

Anti-microtubule activity of tubeimoside I and its colchicine binding site of tubulin.[Pubmed:18030471]

Cancer Chemother Pharmacol. 2008 Sep;62(4):559-68.

BACKGROUND: Tubeimoside I (TBMS1) was isolated from the tubers of Bolbostemma paniculatum (Maxim.) Franquet. TBMS1 shows potent anti-tumor activity. The present study was conducted to investigate the anti-microtubule role of TBMS1 and its binding site of tubulin. METHODS: Cell growth inhibition was measured by MTT after treatment with TBMS1. Uptake kinetics of TBMS1 by human nasopharyngeal carcinoma CNE-2Z cell line (CNE-2Z) was assayed by HPLC. Microtubule protein (MTP) was prepared from porcine brain through two cycles of polymerization-depolymerization in a high molarity buffer. Inhibition of MTP polymerization induced by TBMS1 was determined by a turbidity measurement and a sedimentation assay; the interactions of TBMS1 with tubulin within CNE-2Z cells were investigated by immunofluorescence microscopy and immunoblotting. TBMS1 was tested for its ability to inhibit binding of known tubulin ligands through competitive binding assay. RESULTS: TBMS1 displayed growth inhibitory activity against CNE-2Z cells with IC(50) value of 16.7 microM for 72 h. HPLC analysis of TBMS1 uptake by CNE-2Z cells displayed the initial slow TBMS1 uptake and then gradually reaching an maximum uptake near 18 h. CNE-2Z cells treated with TBMS1 (25 microM, 3 h) were sufficient to cause the microtubular network disruption. Immunoblot analysis showed that the proportion of cytosolic tubulin of cells treated with TBMS1 increased in a time- and concentration-dependent manner. TBMS1 did not inhibit the binding of vinblastine to tubulin. Colchicine binding to tubulin was inhibited in the presence of TBMS1. CONCLUSIONS: TBMS1 is an anti-microtubule agent, and its binding site of tubulin is the colchicine binding site of tubulin.

Cytotoxicity of tubeimoside I in human choriocarcinoma JEG-3 cells by induction of cytochrome c release and apoptosis via the mitochondrial-related signaling pathway.[Pubmed:21687933]

Int J Mol Med. 2011 Oct;28(4):579-87.

Mitochondria play important roles in the intrinsic pathways that trigger apoptosis. Anticancer chemotherapies eliminate cancer cells mainly through the induction of apoptosis. In the present study, we investigated the mechanism of the cytotoxic effects of Tubeimoside I (TBMS1) on the human choriocarcinoma cell line (JEG-3). Choriocarcinoma is one of the most common malignant tumors in the reproductive system. TBMS1, a triterpenoid saponin, isolated from the tubers of Bolbostemma paniculatum (Maxim) Franquet (Cucurbitaceae), showed potent antitumor effects. However, the potential roles of TBMS1 in the treatment of choriocarcinoma remain unknown. In the present study, we examined the effects of TBMS1 on JEG-3 cells. TBMS1 displayed strong growth inhibitory effects on JEG-3 cell growth. In addition, TBMS1 treatment with TBMS1 led to marked cell apoptosis, significant cell cycle arrest at G2 phase and decrease in mitochondrial transmembrane potential (DeltaPsim). Cytochrome c was released from the mitochondria and caspase-3 expression was enhanced. Furthermore, TBMS1 induced the up-regulation of Bcl-2 associated X protein (Bax) expression, down-regulation of Bcl-2 expression, inhibition of nuclear factor-kappa-B (NF-kappaB) function and impacted the phosphorylation of p38 mitogen-activated protein kinase (p38/MAPK), extracellular signal-regulated kinases (ERK)1/2 and protein kinase B (Akt). Taken together, our findings suggest that TBMS1 is an efficient apoptosis-inducing agent for choriocarcinoma cells, which exerts its effects, at least partially, by the induction of mitochondrial dysfunction and regulation of the p38/MAPK, ERK1/2 and PI3K/Akt signaling pathways.

Natural plant extract tubeimoside I promotes apoptosis-mediated cell death in cultured human hepatoma (HepG2) cells.[Pubmed:21628880]

Biol Pharm Bull. 2011;34(6):831-8.

Tubeimoside I (TBMS I), an extract from Chinese herbal medicine Bolbostemma paniculatum (MAXIM.) FRANQUET (Cucurbitaceae) has been shown as a potent anti-tumor agent for a variety of human cancers, but yet to be evaluated for hepatoma that is highly prevalent in Eastern Asian countries including China. Here, we examined in vitro the cytotoxic effects of TBMS I on human hepatoma (HepG2) and normal liver (L-02) cell lines. We also investigated TBMS I-induced molecular events related to apoptosis in HepG2 cells. The results show that TBMS I inhibited the proliferation of both HepG2 and L-02 cells in a dose- and time-dependent manner, but HepG2 cells appeared more sensitive to the agent. When exposed to TBMS I for 24, 48 and 72 h, IC(5)(0) for HepG2 cells versus L-02 cells were 15.5 vs. 23.1, 11.7 vs. 16.2, 9.2 vs. 13.1 (microM, p<0.01), respectively. TBMS I induced cell shrinkage, nuclear condensation and fragmentation, cell cycle arrest at the G2/M phase, mitochondrial membrane disruption, release of cytochrome c from the mitochondria, activation of caspase 3 and 9, and shifting Bax/Bcl-2 ratio from being anti-apoptotic to pro-apoptotic, all indicative of initiation and progression of apoptosis involving mitochondrial dysfunction. Taken together, these results indicate for the first time that TBMS I potently inhibited growth in HepG2 cells by mediating a cascade of apoptosis signaling pathways. Considering its sensitivity of HepG2 cells, preferential distribution in the liver and natural product origin, TBMS I therefore may have a great potential as a chemotherapeutic drug candidate for hepatoma.

Tubeimoside I sensitizes cisplatin in cisplatin-resistant human ovarian cancer cells (A2780/DDP) through down-regulation of ERK and up-regulation of p38 signaling pathways.[Pubmed:21687949]

Mol Med Rep. 2011 Sep-Oct;4(5):985-92.

Cisplatin (CDDP) is a major chemotherapeutic drug used in the treatment of human ovarian cancer. Tubeimoside I (TBMS1) has also shown potent antitumor and antitumor-promoting effects, and may offer a promising new approach in the effective treatment of CDDP-resistant human ovarian cancers. This study aimed to investigate the effect of TBMS1 in sensitizing CDDP in CDDP-resistant human ovarian cancer cells (A2780/DDP). A variety of methods were employed to measure cell apoptosis, p38, ERK1/2 and glutathione S-transferase (GST)-pi expressions. It was found that TBMS1 combined with CDDP promoted cell apoptosis, decreased proliferation activity and increased cytosolic Ca2+ levels. Bcl-2 protein expression was down-regulated but Bax was up-regulated. Moreover, GST-pi mRNA and protein expression were decreased. TBMS1 reduced the resistance of the cells to CDDP-induced cytotoxicity. Both the p38 inhibitor (SB203580) and the ERK1/2 inhibitor (PD98059) effectively blocked this effect. These results suggest that TBMS1 can effectively sensitize CDDP in CDDP-resistant human ovarian cancer cells through the down-regulation of the ERK1/2 and the up-regulation of the p38 signaling pathways.