Cancers:
Cervical, colon, liver, lung, ovarian, liver, breast, hepatocellular
Action: Anti-angiogenic, anti-metastatic, chemo-sensitizer, pro-oxidative, cell-cycle arrest
T cell-mediated autoimmune, induces apoptosis, immune regulating, radio-sensitizer
Induces Apoptosis
Long dan xie gan tang, a well known Chinese herbal formulation, is commonly used by patients with chronic liver disease in China. Accumulated anecdotal evidence suggests that Long dan tang may have beneficial effects in patients with hepatocellular carcinoma. Long dan tang is comprised of five herbs: Gentiana root, Scutellaria root, Gardenia fruit, Alisma rhizome, and Bupleurum root. The cytotoxic effects of compounds from the five major ingredients isolated from the above plants, i.e. gentiopicroside, baicalein, geniposide, alisol B acetate and saikosaponin-d, respectively, on human hepatoma Hep3B cells, were investigated.
Annexin V immunofluorescence detection, DNA fragmentation assays and FACScan analysis of propidium iodide-staining cells showed that gentiopicroside, baicalein, and geniposide had little effect, whereas alisol B acetate and saikosaponin-d profoundly induced apoptosis in Hep3B cells. Alisol B acetate, but not saikosaponin-d, induced G2/M arrest of the cell-cycle as well as a significant increase in caspase-3 activity. Interestingly, baicalein by itself induced an increase in H(2)O(2) generation and the subsequent NF-kappaB activation; furthermore, it effectively inhibited the transforming growth factor-beta(1) (TGF-beta(1))-induced caspase-3 activation and cell apoptosis.
Results suggest that alisol B acetate and saikosaponin-d induced cell apoptosis through the caspase-3-dependent and -independent pathways, respectively. Instead of inducing apoptosis, baicalein inhibits TGF-beta(1)-induced apoptosis via increase in cellular H(2)O(2) formation and NF-kappaB activation in human hepatoma Hep3B cells (Chou, Pan, Teng & Guh, 2003).
Breast
Saikosaponin-A treatment of MDA-MB-231 for 3 hours and of MCF-7 cells for 2 hours, respectively, caused an obvious increase in the sub G1 population of cell-cycles.
Apoptosis in MDA-MB-231 cells was independent of the p53/p21 pathway mechanism and was accompanied by an increased ratio of Bax to Bcl-2 and c-myc levels and activation of caspase-3. In contrast, apoptosis of MCF-7 cells may have been initiated by the Bcl-2 family of proteins and involved p53/p21 dependent pathway mechanism, and was accompanied by an increased level of c-myc protein. The apoptosis of both MDA-MB-231 and MCF-7 cells showed a difference worthy of further research (Chen, Chang, Chung, & Chen, 2003).
Hepatocellular Carcinoma
The signaling pathway mediating induction of p15(INK4b) and p16(INK4a) during HepG2 growth inhibition triggered by the phorbol ester tumor promoter TPA (12-O-tetradecanoylphorbol 13-acetate) and the Chinese herbal compund Saikosaponin A was investigated.
Expressions of proto-oncogene c-jun, junB and c-fos were induced by TPA and Saikosaponin A between 30 minutes to 6 hours of treatment. Pre-treatment of 20 microg/ml PD98059, an inhibitor of MEK (the upstream kinase of ERK), prevents the TPA and Saikosaponin A triggered HepG2 growth inhibition by 50% and 30%, respectively. In addition, AP-1 DNA-binding assay, using non-isotopic capillary electrophoresis and laser-induced fluorescence (CE/LIF), demonstrated that the AP-1-related DNA-binding activity was significantly induced by TPA and Saikosaponin A, which can be reduced by PD98059 pre-treatment.
Results suggest that activation of ERK, together with its downstream transcriptional machinery, mediated p15(INK4b) and p16(INK4a) expression that led to HepG2 growth inhibition (Wen-Sheng, 2003).
The effects of Saikosaponin D (SSd) on syndecan-2, matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases-2 (TIMP-2) in livers of rats with hepatocellular carcinoma (HCC) was investigated.
The model group had more malignant nodules than the SSd group. Model-group HCC cells were grade III; SSd-group HCC cells were grades I-II. Controls showed normal hepatic cell phenotypes and no syndecan-2+ staining. Syndecan-2+ staining was greater in the model group (35.2%, P < or = 0.001) than in controls or the SSd group (16.5%, P < or = 0.001). The model group had more intense MMP-2+ staining than controls (0.37 vs 0.27, P< or =0.01) or the SSd group (0.31 vs 0.37, P< or =0.05); and higher MMP-13+ staining (72.55%) than in controls (12.55%, P< or =0.001) and SSd group (20.18%, P< or =0.01).
The model group also had more TIMP-2+ staining (57.2%) than controls (20.9%, P< or =0.001) and SSd group (22.7%, P< or=0.001). Controls and SSd group showed no difference in TIMP-2+ rates.
SSd inhibited HCC development, and downregulated expression of syndecan-2, MMP-2, MMP-13 and TIMP-2 in rat HCC liver tissue (Jia et al., 2012).
T Cell-mediated Autoimmune
Saikosaponin-d (Ssd) is a triterpene saponin derived from the medicinal plant, Bupleurum falcatum L. (Umbelliferae). Previous findings showed that Ssd exhibits a variety of pharmacological and immunomodulatory activities including anti-inflammatory, anti-bacterial, anti-viral and anti-cancer effects.
Results demonstrated that Ssd not only suppressed OKT3/CD28-costimulated human T cell proliferation, it also inhibited PMA, PMA/Ionomycin and Con A-induced mouse T cell activation in vitro. The inhibitory effect of Ssd on PMA-induced T cell activation was associated with down-regulation of NF-kappaB signaling through suppression of IKK and Akt activities. In addition, Ssd suppressed both DNA binding activity and the nuclear translocation of NF-AT and activator protein 1 (AP-1) of the PMA/Ionomycin-stimulated T cells. The cell surface markers, such as IL-2 receptor (CD25), were also down-regulated along with decreased production of pro-inflammatory cytokines of IL-6, TNF-alpha and IFN-gamma.
Results indicate that the NF-kappaB, NF-AT and AP-1 (c-Fos) signaling pathways are involved in the T cell inhibition evoked by Ssd. Ssd could be a potential candidate for further study in treating T cell-mediated autoimmune conditions (Wong, Zhou, Cheung, Li, & Liu, 2009).
Cervical Cancer
Saikosaponin-a and -d, two naturally occurring compounds derived from Bupleurum radix, have been shown to exert anti-cancer activity in several cancer cell lines. However, the effect of a combination of saikosaponins with chemotherapeutic drugs have never been addressed. Investigated as to whether these two saikosaponins have chemo-sensitization effect on cisplatin-induced cancer cell cytotoxicity was carried out.
Two cervical cancer cell lines, HeLa and Siha, an ovarian cancer cell line, SKOV3, and a non-small-cell lung cancer cell line, A549, were treated with saikosaponins or cisplatin individually or in combination. Cell death was quantitatively detected by the release of lactate dehydrogenase (LDH) using a cytotoxicity detection kit. Cellular ROS was analyzed by flow cytometry. Apoptosis was evaluated by AO/EB staining, flow cytometry after Anexin V and PI staining, and Western blot for caspase activation. ROS scavengers and caspase inhibitor were used to determine the roles of ROS and apoptosis in the effects of saikosaponins on cisplatin-induced cell death.
Both saikosaponin-a and -d sensitized cancer cells to cisplatin-induced cell death in a dose-dependent manner, which was accompanied with induction of reactive oxygen species (ROS) accumulation.
Results suggest that saikosaponins sensitize cancer cells to cisplatin through ROS-mediated apoptosis, and the combination of saikosaponins with cisplatin could be an effective therapeutic strategy (Wang et al., 2010).
Colon Cancer
Saikosaponin-a (SSa)-induced apoptosis of HCC cells was associated with proteolytic activation of caspase-9, caspase-3, and PARP cleavages and decreased levels of IAP family members, such as XIAP and c-IAP-2, but not of survivin. SSa treatment also enhanced the activities of caspase-2 and caspase-8, Bid cleavage, and the conformational activation of Bax. Moreover, inhibition of caspase-2 activation by the pharmacological inhibitor z-VDVAD-fmk, or by knockdown of protein levels using a si-RNA, suppressed SSa-induced caspase-8 activation, Bid cleavage, and the conformational activation of Bax. Although caspase-8 is an initiator caspase like caspase-2, the inhibition of caspase-8 activation by knockdown using a si-RNA did not suppress SSa-induced caspase-2 activation.
Results suggest that sequential activation of caspase-2 and caspase-8 is a critical step in SSa-induced apoptosis (Kim & Hong, 2011).
Immune Regulating
Tumor necrosis factor-alpha (TNF- α ) was reported as an anti-cancer therapy due to its cytotoxic effect against an array of tumor cells. However, its undesirable responses of TNF- α on activating NF- κB signaling and pro-metastatic property limit its clinical application in treating cancers. Therefore, sensitizing agents capable of overcoming this undesirable effect must be valuable for facilitating the usage of TNF- α -mediated apoptosis therapy for cancer patients. Previously, saikosaponin-d (Ssd), a triterpene saponin derived from the medicinal plant, Bupleurum falcatum L. (Umbelliferae), exhibited a variety of pharmacological activities such as anti-inflammatory, anti-bacterial, anti-viral and anti-cancer.
Investigation found that Ssd could potentially inhibit activated T lymphocytes via suppression of NF- κ B, NF-AT and AP-1 signaling. Ssd significantly potentiated TNF- α -mediated cell death in HeLa and HepG2 cancer cells via suppression of TNF- α -induced NF- κ B activation and its target genes expression involving cancer cell proliferation, invasion, angiogenesis and survival. Also, Ssd revealed a significant potency in abolishing TNF- α -induced cancer cell invasion and angiogenesis in HUVECs while inducing apoptosis via enhancing the loss of mitochondrial membrane potential in HeLa cells.
Collectively, findings indicate that Ssd has significant potential to be developed as a combined adjuvant remedy with TNF- α for cancer patients (Wong et al., 2013).
Radio-sensitizer
Saikosaponin-d (SSd), a monomer terpenoid purified from the Chinese herbal drug Radix bupleuri, has multiple effects, including anti-cancer properties. Treatment with SSd alone and radiation alone inhibited cell growth and increased apoptosis rate at the concentration used. These effects were enhanced when SSd was combined with radiation. Moreover, SSd potentiated the effects of radiation to induce G0/G1 arrest in SMMC-7721 hepatocellular carcinoma cells, and reduced the G2/M-phase population under hypoxia. SSd potentiates the effects of radiation on SMMC-7721 cells; thus, it is a promising radio-sensitizer. The radio-sensitizing effect of SSd may contribute to its effect on the G0/G1 and G2/M checkpoints of the cell-cycle (Wang et al., 2013).
References