Platycodin D induces apoptotic cell death through PI3K/AKT and MAPK/ERK pathways and synergizes with venetoclax in acute myeloid leukemia

Acute myeloid leukemia (AML) is a highly heterogeneous and rapidly progressive hematopoietic neoplasm characterized by frequent relapses and variable prognoses. The development of new treatment options, therefore, is of crucial importance. Platycodin D (PD) is a triterpenoid saponin, extracted from the roots of the traditional Chinese herbal medicine Platycodon grandiflorum (Jacq.) A. DC., which has been reported to exhibit therapeutic potential against a broad range of cancers. Although the effects of PD on AML remain unclear, in the present study, we observed a concentration-dependent reduction in the viability of multiple human AML cell lines in response to treatment with PD. In addition to triggering mitochondria-dependent apoptosis via the upregulation of BAK and BIM, treatment with PD also induced cell cycle arrest at the G0/G1 phase. Western blot analyses revealed marked suppression of the phosphorylation of protein kinase B (AKT), glycogen synthase kinase-3β, ribosomal protein S6, and extracellular signal-regulated kinase (ERK) by PD, in turn implying the participation of the phosphoinositide 3-kinase (PI3K)/AKT and mitogen-activated protein kinase (MAPK)/ERK pathways. Pre-incubation with LY294002, MK2206, AR-A014418, or U0126 was consistently found to significantly aggravate PD-induced inhibition of viability. Additionally, PD combined with the B-cell lymphoma 2 (BCL2) inhibitor venetoclax elicited synergistically enhanced cytotoxic effects. The anti-leukemic activity of PD was further validated using primary samples from de novo AML patients. Given the results of the present study, PD may be a potent therapeutic candidate for the treatment of AML.

Platycodin D induces proliferation inhibition and mitochondrial apoptosis in diffuse large B-cell lymphoma

Patients with diffuse large B-cell lymphoma (DLBCL) have unsatisfactory outcomes especially when relapse occurs after initial chemotherapy. Platycodin D (PD), a triterpenoid saponin isolated from the root of Platycodon grandiflorum (Jacq.) A. DC., has demonstrated potent anti-cancer activities. So far, however, information regarding the effect of PD on malignant lymphoma remains unavailable. In the present study, we showed that PD dose-dependently inhibited the viability of a serial of established DLBCL cell lines representing different molecular subtypes, and their sensitivities to PD were comparable. Mitochondrial dysfunction and subsequent intrinsic apoptosis were induced by PD, as indicated by the loss of mitochondrial membrane potential and the increase in the percentage of Annexin Ⅴ positive cells. Mechanistically, PD treatment downregulated expression levels of anti-apoptotic proteins including MCL-1, BCL-2, and BCL-XL, while upregulated the expression level of pro-apoptotic protein BAK, followed by the cleavage of PARP. Moreover, PD synergistically enhanced the cytotoxicity of BCL-2 inhibitor venetoclax. In a SUDHL-4-derived xenograft mouse model, PD administration significantly constrained the tumor growth without obvious side effects. Therefore, our results provided new insights into the role of PD in lymphoma therapy.

Platycodin D inhibits the proliferation and migration of hypertrophic scar-derived fibroblasts and promotes apoptosis through a caspase-dependent pathway

Abnormal fibroblast proliferation and excessive extracellular matrix (ECM) deposition lead to the formation of hypertrophic scars (HSs). However, there is no satisfactory method to inhibit the occurrence and development of HSs. In our study, platycodin D (PD), a natural compound extracted from Platycodon grandiflorus, inhibited HSs formation both in vitro and in vivo. First, qRT-PCR and Western blot were used to confirm PD dose-dependently downregulated the expression of Col I, Col III and α-SMA in human hypertrophic scar-derived fibroblasts (HSFs) (p < 0.05). Second, cck-8, transwell and wound healing assays verified PD suppressed the proliferation (p < 0.05) and migration of HSFs (p < 0.05), and inhibited the differentiation of HSFs into myofibroblasts. Moreover, PD-induced HSFs apoptosis were analyzed by flow cytometry and the apoptosis was activated through a caspase-dependent pathway. The rabbit ear scar model was used to further confirm the inhibitory effect of PD on collagen and α-SMA deposition. Finally, Western blot analysis showed that PD reduced TGF-β RI expression (p < 0.05) and affected matrix metalloproteinase 2 (MMP2) protein levels (p < 0.05). In conclusion, our study showed that PD inhibited the proliferation and migration of HSFs by inhibiting fibrosis-related molecules and promoting apoptosis via a caspase-dependent pathway. The TGF-β/Smad pathway also mediated the inhibition of HSFs proliferation and HSFs differentiation into myofibroblasts. Therefore, PD is a potential therapeutic agent for HSs and other fibrotic diseases.

Platycodin D sensitizes KRAS-mutant colorectal cancer cells to cetuximab by inhibiting the PI3K/Akt signaling pathway

Cetuximab is a monoclonal antibody against epidermal growth factor receptor that blocks downstream signaling pathways of receptor tyrosine kinases, including Ras/Raf/MAPK and PI3K/Akt, thereby inhibiting tumor cell proliferation and inducing cancer cell apoptosis. Owing to KRAS mutations, the effectiveness of cetuximab is usually limited by intrinsic drug resistance. Continuous activation of the PI3K/Akt signaling pathway is another reason for cetuximab resistance. Platycodin-D, a bioactive compound isolated from the Chinese herb Platycodon grandiflorum, regulates Akt in different trends based on tissue types. To investigate whether platycodin-D can sensitize KRAS-mutant colorectal cancer cells to cetuximab by inhibiting the PI3K/Akt signaling pathway, HCT116 and LoVo cells were treated with cetuximab and platycodin-D. LY294002 and SC79 were used to regulate Akt to further evaluate whether platycodin-D sensitizes cells to cetuximab by inhibiting Akt. Our results confirmed that platycodin-D increased the cytotoxic effects of cetuximab, including inhibition of growth, migration, and invasion, via downregulation of PI3K and Akt phosphorylation in HCT116 and LoVo cells both in vitro and in vivo. Given these data, platycodin-D may sensitize KRAS-mutant colorectal cancer cells to cetuximab via inhibition of the PI3K/Akt signaling pathway.

Platycodon D-induced A549 cell apoptosis through RRM1-regulated p53/VEGF/MMP2 pathway

BACKGROUND

Lung cancer is one of the leading causes of cancer-related deaths worldwide. Platycodin D (PD), a major pharmacological constituent from the Chinese medicinal herb named Platycodonis Radix, has shown potent anti-tumor activity. Also, it is also reported that PD could inhibit cellular growth in the non-small-cell lung carcinoma (NSCLC) A549 cell line. However, the underlying mechanism is not fully clarified.

METHODS

Cell proliferation was measured by MTT assay. Annexin V and propidium iodide (PI) assay were employed to study the apoptosis effects of PD on A549 cells. Western blot analysis was used to evaluate protein expression. Also, we used a siRNA against p53, as well as a plasmid-based RRM1 over-expression to investigate their functions.

RESULTS

It demonstrated PD inhibited A549 cell proliferation in a dose- and time-dependent manner. Further investigations showed that PD induced cell apoptosis, which was supported by dose-dependent and time-dependent caspase-3 activation and p53/VEGF/MMP2 pathway regulation. Also, PD demonstrated the inhibition effect of ribonucleotide reductase M1 (RRM1), whose role in various tumors is contradictory. Remarkably, in this work, RRM1 overexpression in A549 cells could have a negative impact on the regulation of the p53/VEGF/MMP2 pathway induced by PD treatment. Note as well that RRM1 overexpression also attenuated cell apoptosis and inhibition of cell proliferation of A549 treated with PD.

CONCLUSION

The results suggested that PD could inhibit A549 cell proliferation and induce cell apoptosis by regulating p53/VEGF/MMP2 pathway, in which RRM1 plays an important role directly.

Immunometabolism modulation, a new trick of edible and medicinal plants in cancer treatment

The edible and medicinal plants (EMPs) are becoming an abundant source for cancer prevention and treatment since the natural and healthy trend for modern human beings. Currently, there are more than one hundred species of EMPs widely used and listed by the national health commission of China, and most of them indicate immune or metabolic regulation potential in cancer treatment with numerous studies over the past two decades. In the present review, we focused on the metabolic influence in immunocytes and tumor microenvironment, including immune response, immunosuppressive factors and cancer cells, discussing the immunometabolic potential of EMPs in cancer treatment. There are more than five hundred references collected and analyzed through retrieving pharmacological studies deposited in PubMed by medical subject headings and the corresponding names derived from pharmacopoeia of China as a sole criterion. Finally, the immunometabolism modulation of EMPs was sketch out implying an immunometabolic control in cancer treatment.

In vitro and in vivo evaluation of a water-in-oil microemulsion of platycodin D

Platycodin D (PD) is the active metabolite of Platycodon grandiflorum. The main purpose of this study was to develop and evaluate a water-in-oil (W/O) microemulsion formulation of PD (PD-ME). The PD-ME was successfully prepared by the water titration method at K m  = 2, to draw the pseudoternary phase diagrams. Physical characterization including the particle size, pH, refractive index, average viscosity, and polydispersity index (PDI) was performed. The in vivo characteristics were evaluated by intestinal permeability and pharmacokinetic studies. The optimized microemulsion formulation consisted of 100 mg/ml PD aqueous solution, soybean phospholipids, ethanol, and oleic acid (27:39:19:15, w/w). The average viscosity, pH, droplet size, PDI, and zeta potential of the PD-ME were 78.65 ± 0.13 cPa•s, 5.70 ± 0.05, 30.46 ± 0.20 nm, 0.33 ± 0.00, and -3.13 mV, respectively. The drug concentration of the PD-ME was 26.3 ± 0.6 mg/ml. The PD-ME showed significantly higher apparent permeability coefficients than PD (p < .01). The pharmacokinetic studies showed that the PD-ME had significantly higher values of T 1/2 (2.26-fold), AUC0-24h (area under the curve; 1.65-fold), and MRT0-24h (1.58-fold) than PD (p < .01). It can be seen that W/O ME presents a strategy with great promise for enhancing the intestinal permeability and better oral absorption of drugs with high polarity and poor permeability.

Terpenoids' anti-cancer effects: focus on autophagy

Terpenoids are the largest class of natural products, most of which are derived from plants. Amongst their numerous biological properties, their anti-tumor effects are of interest for they are extremely diverse which include anti-proliferative, apoptotic, anti-angiogenic, and anti-metastatic activities. Recently, several in vitro and in vivo studies have been dedicated to understanding the 'terpenoid induced autophagy' phenomenon in cancer cells. Light has already been shed on the intricacy of apoptosis and autophagy relationship. This latter crosstalk is driven by the delicate balance between activating or silencing of certain proteins whereby the outcome is expressed via interrelated signaling pathways. In this review, we focus on nine of the most studied terpenoids and on their cell death and autophagic activity. These terpenoids are grouped in three classes: sesquiterpenoid (artemisinin, parthenolide), diterpenoids (oridonin, triptolide), and triterpenoids (alisol, betulinic acid, oleanolic acid, platycodin D, and ursolic acid). We have selected these nine terpenoids among others as they belong to the different major classes of terpenoids and our extensive search of the literature indicated that they were the most studied in terms of autophagy in cancer. These terpenoids alone demonstrate the complexity by which these secondary metabolites induce autophagy via complex signaling pathways such as MAPK/ERK/JNK, PI3K/AKT/mTOR, AMPK, NF-kB, and reactive oxygen species. Moreover, induction of autophagy can be either destructive or protective in tumor cells. Nevertheless, should this phenomenon be well understood, we ought to be able to exploit it to create novel therapies and design more effective regimens in the management and treatment of cancer.

Effects of Platycodin D on apoptosis, migration, invasion and cell cycle arrest of gallbladder cancer cells

Platycodin D (PD) is a triterpenoid saponin that exists in the roots of Platycodonis. It exhibits evident growth inhibitory effects and potent cytotoxicity against multiple types of cancer. Gallbladder cancer (GBC) is the most common malignant disease of the biliary tract system. Patients with GBC usually have limited available treatment strategies and a poor prognosis. The present study investigated the antitumor effects of PD on human GBC cells in vitro and its underlying molecular mechanisms of action. The results indicated that PD, as assessed using MTT and colony forming assays, induced evident growth inhibition. Flow cytometry indicated that PD robustly induced apoptosis and blocked GBC cells at the G₂/M phase. Cell migration and invasion assays demonstrated that PD effectively inhibited the migratory and invasive abilities of GBC cell lines. Western blotting indicated that PD may initiate mitochondrial destruction in GBC cells through the JNK signaling pathway, thereby inducing apoptosis. The present results indicated that PD may exhibit antitumor effects by inducing apoptosis; inhibiting migration and invasion; and affecting the cell cycle in GBC cells. Therefore, PD has the potential to become a novel antitumor drug for GBC therapy.

The Pharmacological Effects and Health Benefits of Platycodon grandiflorus-A Medicine Food Homology Species

Platycodon grandiflorus is a widely used edible, traditional Chinese medicinal herb. It is rich in saponins, flavonoids, phenolic acids, and other compounds. It contains a large number of fatty acids such as linoleic acid (up to 63.24%), a variety of amino acids, vitamins, and multiple essential trace elements. P. grandiflorus has several biological applications, such as in hypotension, lipid reduction, atherosclerosis, inflammation, relieving cough and phlegm, promoting cholic acid secretion, and as an antioxidant. Further, P. grandiflorus is often used in the development of cold mixed vegetables, canned vegetables, preserved fruit, salted vegetables, and cosmetics in northeast China, South Korea, Japan, and Korea. In this paper, the active chemical components and the health benefits of P. grandiflorus have been reviewed, providing new ideas for the further development of nutraceutical products to prevent and manage chronic diseases.

Platycodin D inhibits platelet function and thrombus formation through inducing internalization of platelet glycoprotein receptors

Background

Platycodin D (PD) is one of the major bioactive components of the roots of Platycodon grandiflorum and possesses multiple biological and pharmacological properties, such as antiviral, anti-inflammatory, and anti-cancer activities. However, whether it affects platelet function remains unclear. This study aims to evaluate the role of PD in platelet function and thrombus formation.

Methods

Platelets were treated with PD followed by measuring platelet aggregation, activation, spreading, clot retraction, expression of glycoprotein receptors. Moreover, mice platelets were treated with PD and infused into wild-type mice for analysis of in vivo hemostasis and arterial thrombosis.

Results

Platycodin D treatment significantly inhibited platelet aggregation in response to collagen, ADP, arachidonic acid and epinephrine, reduced platelet P-selectin expression, integrin α_IIbβ₃ activation, spreading on fibrinogen as well as clot retraction, accompanied with decreased phosphorylation of Syk and PLCγ2 in collagen-related peptide or thrombin-stimulated platelets. Moreover, PD-treated mice platelets presented significantly impaired in vivo hemostasis and arterial thrombus formation. Interestingly, PD induced internalization of glycoprotein receptors α_IIbβ₃, GPIbα and GPVI. However, GM6001, cytochalasin D, BAPTA-AM and wortmannin did not prevent PD-induced internalization of receptors.

Conclusions

Our study demonstrates that PD inhibits platelet aggregation, activation and impairs hemostasis and arterial thrombosis, suggesting it might be a potent anti-thrombotic drug.

Non-apoptotic cell death in malignant tumor cells and natural compounds

Traditional cancer therapy is mainly targeting on enhancing cell apoptosis, however, it is well established that many cancer cells are chemo-resistant and defective in apoptosis induction. Therefore, it may have important therapeutic implications to exploit some novel natural compounds based on non-apoptotic programmed cell death. Currently, accumulating evidence shows that the compounds from nature source can induce non-apoptotic programmed cell death in cancer cells, and therefore these natural compounds have gained a great promise for the future anticancer therapeutics. In this review, we will concentrate our efforts on the latest developments regarding major forms of non-apoptotic programmed cell death--autophagic cell death, necroptosis, ferroptosis, pyroptosis, glutamoptosis and exosome-associated cell death. Our increased understanding of the role of natural compounds in regulating non-apoptotic programmed cell death will hopefully provide prospective strategies for cancer therapy.

Molecular cloning and characterization of the genes encoding the proteins of Zika virus

Zika virus (ZIKV) encodes a precursor protein (also called polyprotein) of about 3424 amino acids that is processed by proteases to generate 10 mature proteins and a small peptide. In the present study, we characterized the chemical features, suborganelle distribution and potential function of each protein using Flag-tagged protein expression system. Western blot analysis revealed the molecular weight of the proteins and the polymerization of E, NS1, and NS3 proteins. In addition, we performed multi-labeled fluorescent immunocytochemistry and subcellular fractionation to determine the subcellular localization of these proteins in host cells. We found that 1) the capsid protein colocalizes with 3 different cellular organelles: nucleoli, Golgi apparatus, and lipid droplet; NS2b and NS4a are associated with the Golgi apparatus; 2) the capsid and NS1proteins distribute in both cytoplasm and nucleus, NS5 is a nuclear protein; 3) NS3 protein colocalizes with tubulin and affects Lamin A; 4) Envelope, PrM, and NS2a proteins co-localize with the endoplasmic reticulum; 5) NS1 is associated with autophagosomes and NS4b is related to early endosome; 6) NS5 forms punctate structures in the nucleus that associate with splicing compartments shown by SC35, leading to reduction of SC35 protein level and trafficking of SC35 from the nucleus to the cytoplasm. These data suggest that ZIKV generates 10 functional viral proteins that exhibit distinctive subcellular distribution in host cells.

Platycodin D exerts anti-tumor efficacy in H22 tumor-bearing mice via improving immune function and inducing apoptosis

Platycodin D (PD), a major saponin derived and isolated from the roots of Platycodon grandiflorum, exerts potent growth inhibition and strong cytotoxicity against various cancer cell lines. However, the anti-tumor efficacy of PD on H22 hepatocellular carcinoma remains unknown. In the present study, we aimed to explore the anti-hepatoma activity in vivo and the underlying mechanism of PD in H22 tumor-bearing mice. The results revealed that PD could considerably suppress tumor growth with no significant side effects on immune organs and body weight. Further investigations showed that the levels of serum cytokines, including interferon gamma (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-2 (IL-2), were enhanced by PD administration. On the other hand, PD inhibited the production of vascular endothelial growth factor (VEGF) in serum of H22 tumor mice. Additionally, the observations from H&E and Hoechst 33258 staining results demonstrated that PD noticeably induced apoptosis in H22 hepatocellular carcinoma cells. Importantly, immunohistochemical analysis showed that PD treatment increased Bax expression and decreased Bcl-2 and VEGF expression of H22 tumor tissues in a dose-dependent manner. Taken together, the findings in the present investigation clearly demonstrated that the PD markedly suppressed the tumor growth of H22 transplanted tumor in vivo at least partly via improving the immune functions, inducing apoptosis, and inhibiting angiogenesis.

A platycoside-rich fraction from the root of Platycodon grandiflorum enhances cell death in A549 human lung carcinoma cells via mainly AMPK/mTOR/AKT signal-mediated autophagy induction

ETHNOPHARMACOLOGICAL RELEVANCE

The root of Platycodon grandiflorum (PG), commonly known as Kilkyong in Korea, Jiegeng in China, and Kikyo in Japan, has been extensively used as a traditional anti-inflammatory medicine in Asia for the treatment of respiratory conditions, such as bronchitis, asthma, and tonsillitis. Platycosides isolated from PG are especially well-known for their anti-cancer effects.

AIM OF THE STUDY

We investigated the involvement of autophagic cell death and other potential molecular mechanisms induced by the platycoside-containing butanol fraction of PG (PGB) in human lung carcinoma cells.

MATERIALS AND METHODS

PGB-induced growth inhibition and cell death were measured using a 5-diphenyl-tetrazolium bromide (MTT) assay. The effects of PGB on autophagy were determined by observing microtubule-associated protein 1 light chain 3 (LC3) redistribution with confocal microscopy. The PGB-mediated regulation of autophagy-associated proteins was investigated using Western blotting analysis. Furthermore, the anti-cancer mechanism of PGB was confirmed using chemical inhibitors. A high-performance liquid chromatography (HPLC)-DAD system was used to analyze the platycosides in PGB.

RESULTS

In A549 cells, PGB induced significant autophagic cell death. Specifically, PGB upregulated LC3-II in a time- and dose-dependent manner, and it redistributed LC3 via autophagosome formation in the cytoplasm. PGB treatment increased the phosphorylation of AMP-activated protein kinase (AMPK) and subsequently suppressed the AKT/mammalian target of the rapamycin (mTOR) pathway. Furthermore, PGB inhibited cell proliferation by regulating the mitogen-activated protein kinase (MAPK) pathways. In this study, six types of platycosides were identified in the PGB using HPLC.

CONCLUSIONS

PGB efficiently induced cancer cell death via autophagy and the modulation of the AMPK/mTOR/AKT and MAPK signaling pathways in A549 cells. Therefore, PGB may be an efficacious herbal anti-cancer therapy.

Platycodin D induced apoptosis and autophagy in PC-12 cells through mitochondrial dysfunction pathway

In this article, the in vitro cytotoxicity of platycodin D was evaluated in human PC-12, SGC-7901, BEL-7402, HeLa and A549 cancer cell lines. PC-12 cells were sensitive to platycodin D treatment, with an IC50 value of 13.5±1.2μM. Morphological and comet assays showed that platycodin D effectively induced apoptosis in PC-12 cells. Platycodin D increased the levels of reactive oxygen species (ROS) and induced a decrease in mitochondrial membrane potential. Platycodin D induced cell cycle arrest at the G0/G1 phase in the PC-12 cell line. Platycodin D can induce autophagy. In addition, platycodin D can down-regulate the expression of Bcl-2 and Bcl-x, and up-regulate the levels of Bid protein in the PC-12 cells. The results demonstrated that platycodin D induced PC-12 cell apoptosis through a ROS-mediated mitochondrial dysfunction pathway.

Platycodin D, a metabolite of Platycodin grandiflorum, inhibits highly metastatic MDA-MB-231 breast cancer growth in vitro and in vivo by targeting the MDM2 oncogene

The objective of the present study was to explore the in vitro and in vivo anticancer effects of Platycodin D (PD), derived from Platycodin grandiflorum, on highly metastatic MDA-MB-231 breast cancer cells. Using the MTT assay, we found that PD inhibited MDA-MB-231 cell growth in a concentration-dependent manner, with an IC50 value of 7.77±1.86 µM. Further studies showed that PD had anti-proliferative effects and induced cell cycle arrest in the G0/G1 phase. To explore the detailed mechanism(s) by which PD suppressed MDA-MB-231 cell growth, western blot analyses were used to detect the expression levels of proteins related to cell proliferation and survival. The data showed that PD decreased the expression of proteins related to the G0/G1 phases, downregulated the protein expression of MDM2, MDMX, and mutant p53, and increased the expression levels of p21 and p27 in vitro. We verified the effects of PD on the expression of MDM2, MDMX, mutant p53, p21 and p27 using a pcDNA3-Flag-MDM2 plasmid and MDM2 siRNA transfection, and found that PD inhibited MDA-MB-231 cell viability by targeting MDM2 and mutant p53. Compared with the corresponding parental cells, the cells with siRNA-MDM2 transfection had a greater decrease in cell viability and proliferation, while those with pcDNA3-MDM2 plasmid transfection did not show any increase in the effects of PD. We also established a MDA-MB-231 xenograft model in BALB/c nude mice, and found that PD significantly inhibited the growth of MDA-MB-231 xenograft tumors in these mice. The expression levels of various proteins in the tumor tissue exhibited changes similar to those observed in vitro. These findings indicate that PD exerted in vitro and in vivo anticancer effects against MDA-MB-231 breast cancer cells, that PD is a potential MDM2/MDMX inhibitor, and that the anticancer effects of PD were likely associated with its inhibition of these proteins. Our observations help to identify a mechanism by which PD functions as an anti-breast cancer agent.

Proteomic analysis of hepatocellular carcinoma HepG2 cells treated with platycodin D

Platycodin D (PD), a triterpenoid saponin isolated from Platycodonis Radix, is a famous Chinese herbal medicine that has been shown to have anti-proliferative effects in several cancer cell lines. The aim of this study was to determine the changes in cellular proteins after the treatment of hepatocellular carcinoma HepG2 cells with PD using proteomics approaches. The cell viability was determined using the MTT assay. The proteome was analyzed by two-dimensional difference gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Western blot analysis was used to confirm the expression of changed proteins. Our results showed that PD inhibited the proliferation of HepG2 cells in concentration- and time-dependent manners. Sixteen proteins were identified to be up-regulated in PD-treated HepG2 cells, including ATP5H, OXCT1, KRT9, CCDC40, ERP29, RCN1, ZNF175, HNRNPH1, HSP27, PA2G4, PHB, BANF1, TPM3, ECH1, LGALS1, and MYL6. Three proteins (i.e., RPS12, EMG1, and KRT1) decreased in HepG2 cells after treatment with PD. The changes in HSP27 and PHB were further confirmed by Western blotting. In conclusion, our results shed new lights on the mechanisms of action for the anti-cancer activity of PD.

Platycodin D Attenuates Airway Inflammation in a Mouse Model of Allergic Asthma by Regulation NF-κB Pathway

In this work, the anti-asthma potential of platycodin D (PLD) was studied by investigation of its effect to suppress airway inflammation, a murine model of asthma and the possible mechanisms. A total of 50 mice were randomly assigned to five experimental groups: control, ovalbumin (OVA), OVA+dexamethasone (2 mg/kg) and OVA+PLD (40, 80 mg/kg). Airway resistance (Raw) were measured; airway histological studies were evaluated by the hematoxylin and eosin (HE) staining; interleukin-4 (IL-4), interleukin-5(IL-5), and interleukin-13 in bronchoalveolar lavage fluid (BALF) were evaluated by enzyme-linked immunosorbent assay (ELISA); NF-κBp65, p-NF-κBp65, p-IKKα, IKKα, p-IKKβ, p-IкBα, and IкBα of airway were measured by Western blotting. Our study demonstrated that PLD inhibited OVA-induced increases in Raw and eosinophil count in airway; IL-4, IL-5, and IL-13 were recovered in BALF. Histological studies demonstrated that PLD substantially inhibited OVA-induced eosinophilia in airway tissue. Western blotting studies demonstrated that PLD substantially inhibited NF-κB pathway. These findings suggest that PLD may effectively ameliorate the progression of asthma and could be used as a therapy for patients with allergic asthma.

Platycodin D inhibits B16F10 melanoma metastasis via antiangiogenic activity

Platycodin D inhibits B16F10 melanoma metastasisviaantiangiogenic activity.

Killing cancer with platycodin D through multiple mechanisms

Cancer is a multi-faceted disease comprised of a combination of genetic, epigenetic, metabolic and signalling aberrations which severely disrupt the normal homoeostasis of cell growth and death. Rational developments of highly selective drugs which specifically block only one of the signalling pathways have been associated with limited therapeutic success. Multi-targeted prevention of cancer has emerged as a new paradigm for effective anti-cancer treatment. Platycodin D, a triterpenoid saponin, is one the major active components of the roots of Platycodon grandiflorum and possesses multiple biological and pharmacological properties including, anti-nociceptive, anti-atherosclerosis, antiviral, anti-inflammatory, anti-obesity, immunoregulatory, hepatoprotective and anti-tumour activities. Recently, the anti-cancer activity of platycodin D has been extensively studied. The purpose of this review was to give our perspectives on the current status of platycodin D and discuss its anti-cancer activity and molecular mechanisms which may help the further design and conduct of pre-clinical and clinical trials to develop it successfully into a potential lead drug for oncological therapy. Platycodin D has been shown to fight cancer by inducing apoptosis, cell cycle arrest, and autophagy and inhibiting angiogenesis, invasion and metastasis by targeting multiple signalling pathways which are frequently deregulated in cancers suggesting that this multi-target activity rather than a single effect may play an important role in developing platycodin D into potential anti-cancer drug.

Platycodin D induces apoptosis and triggers ERK- and JNK-mediated autophagy in human hepatocellular carcinoma BEL-7402 cells

AIM

Platycodin D, the main saponin isolated from Chinese herb Platycodonis Radix, exhibits anticancer activities against various cancer cell lines. Here we evaluated its anticancer action against human hepatocellular carcinoma cells in vitro and in vivo, and elucidated the relationship between platycodin D-induced apoptosis and autophagy.

METHODS

The viability of human hepatocellular carcinoma BEL-7402 cells was evaluated with MTT assay, and the apoptosis was examined using Annexin V/PI and Hoechst 33342 staining assays. Monodansylcadaverine (MDC) staining was used to label autophagic vacuoles. The proteins were detected using Western blot analysis. For studying its anticancer action in vivo, platycodin D (5 and 10 mg· kg(-1)·d(-1)) was intraperitoneally injected to BEL-7402-bearing mice for 21 days.

RESULTS

Platycodin D (5-40 μmol/L) inhibited the cell proliferation in vitro with IC50 values of 37.70±3.99, 24.30±2.30 and 19.70±2.36 μmol/L at 24, 48 and 72 h, respectively. Platycodin D (5-20 μmol/L) dose-dependently increased BEL-7402 cell apoptosis, increased the Bax/Bcl-2 ratio and the levels of cleaved PARP and cleaved caspase-3, and decreased the level of Bcl-2. Furthermore, platycodin D (5-20 μmol/L) induced autophagy in BEL-7402 cells, as evidenced by formation of cytoplasmic vacuoles, increased amounts of LC3-II, and increased numbers of MDC-positive cells. Pretreatment with the autophagy inhibitor chloroquine (5 μmol/L) or BAF (50 nmol/L) significantly enhanced platycodin D-induced proliferation inhibition and apoptosis. Moreover, platycodin D (20 μmol/L) activated the ERK and JNK pathways in BEL-7402 cells, and simultaneous blockage of the two pathways effectively suppressed platycodin D-induced autophagy and enhanced platycodin D-induced apoptosis. In BEL-7402-bearing mice, platycodin D (10 mg·kg(-1)•d(-1)) significantly reduced relative tumor volume with decreased body weight.

CONCLUSION

Platycodin D not only inhibits the proliferation of BEL-7402 cells but also suppresses BEL-7402 xenograft tumor growth. Platycodin D-induced cell proliferation inhibition and apoptosis are amplified by co-treatment with autophagy inhibitors.

Platycodin D induces tumor growth arrest by activating FOXO3a expression in prostate cancer in vitro and in vivo

Platycodin D (PD), a major saponin derived from Platycodin grandiflorum, exerted cytotoxicity against prostate cancer cell lines (PC3, DU145 and LNCaP cells) with IC₅₀ values in the range of 11.17 to 26.13μmol/L, whereas RWPE-1cells (a non-malignant human prostate epithelial cell line) were not significantly affected. A further study in these cell lines showed that PD could potently affect cell proliferation (indicated by the bromodeoxyuridine assay), induce cell apoptosis (determined by Annexin V-FITC flow cytometry) and cause cell cycle arrest (indicated by PI staining). After being treated with PD for 48 hours, DU145 and LNCaP cells were arrested in the G0 /G1 phase, and PC3 cells were arrested in the G2/M phase. A Western blotting analysis indicated that PD increased the expression of the FOXO3a transcription factor, decreased the expression of p-FOXO3a and MDM2 and increased the expression of FOXO-responsive genes, p21 and p27. MDM2 silencing (transiently by siRNA-MDM2) increased the PD-induced FOXO3a protein expression, while MDM2 overexpression (in cells transiently transfected with a pcDNA3-MDM2 plasmid) decreased the PD-induced expression of the FOXO3a protein. Moreover, PD dose-dependently inhibited the growth of PC3 xenograft tumors in BALB/c nude mice. A Western blotting analysis of the excised xenograft tumors indicated that similar changes in protein expression also occurred in vivo. These results suggest that PD exhibits significant activity against prostate cancer in vitro and in vivo. The FOXO3a transcription factor appears to be involved in the activity of PD. Together, all of these findings provide a basis for the future development of this agent for human prostate cancer therapy.

SAMHD1 Inhibits LINE-1 Retrotransposition by Promoting Stress Granule Formation

The SAM domain and HD domain containing protein 1 (SAMHD1) inhibits retroviruses, DNA viruses and long interspersed element 1 (LINE-1). Given that in dividing cells, SAMHD1 loses its antiviral function yet still potently restricts LINE-1, we propose that, instead of blocking viral DNA synthesis by virtue of its dNTP triphosphohydrolase activity, SAMHD1 may exploit a different mechanism to control LINE-1. Here, we report a new activity of SAMHD1 in promoting cellular stress granule assembly, which correlates with increased phosphorylation of eIF2α and diminished eIF4A/eIF4G interaction. This function of SAMHD1 enhances sequestration of LINE-1 RNP in stress granules and consequent blockade to LINE-1 retrotransposition. In support of this new mechanism of action, depletion of stress granule marker proteins G3BP1 or TIA1 abrogates stress granule formation and overcomes SAMHD1 inhibition of LINE-1. Together, these data reveal a new mechanism for SAMHD1 to control LINE-1 by activating cellular stress granule pathway.

Long interspersed element 1 (LINE-1 or L1) comprises 17% of human genome, and has played a major role in shaping the evolution of human genome. Approximately 100 copies of LINE-1 are still active in an average individual genome. Movement of these LINE-1 sequences to new loci in the genome has the potential of causing sporadic cases of disease. Among the multi-layered mechanisms by which the host controls LINE-1 activity is a group of host restriction factors including APOBEC3 proteins. SAMHD1 was known for the association of its mutations with the Aicardi-Goutieres syndrome (AGS), a congenital autoimmune disease. SAMHD1 was recently reported as a host restriction factor that inhibits a number of retroviruses and DNA viruses including human immunodeficiency virus type 1 (HIV-1) and herpes simplex virus 1 (HSV-1). Here, we demonstrate that SAMHD1 inhibits LINE-1 retrotransposition through promoting the sequestration of LINE-1 RNP within the cytoplasmic stress granules. SAMHD1 promotes the formation of large stress granules by inducing phosphorylation of eIF2α and disrupting eIF4A/eIF4G interaction. This is the first report describing the role of SAMHD1 in modulating the formation of stress granules. We envision that this function of SAMHD1 not only contributes to the inhibition of LINE-1, but also the restriction of various viruses.

Platycodin-D Induced Autophagy in Non-Small Cell Lung Cancer Cells via PI3K/Akt/mTOR and MAPK Signaling Pathways

Platycodin-D (PD) is an effective triterpene saponin extracted from the root of Platycodon grandiflorum which has been used clinically to treat pulmonary diseases in traditional Chinese medicine. Recently, it has been reported that PD has anti-tumor effects in various cancer models through the induction of apoptosis. However, whether PD induces autophagy in both cell lines and its molecular mechanisms have not been elucidated. Here, our present study confirmed that PD induced autophagy in both NCI-H460 and A549 cells via up-regulating the expression levels of Atg-3, Atg-7 and Beclin-1. Meanwhile, PD contributed to the up-regulation of LC3-II at both protein and mRNA levels. Further detection of the PI3K/Akt/mTOR signaling pathway compared to LY294002 (PI3K kinase inhibitor), RAP (mTOR kinase inhibitor) and insulin (an activator of PI3K/Akt/mTOR signaling pathway) showed that PD induced autophagy through inhibiting the pathway at p-Akt (Ser473), p-p70S6K (Thr389) and p-4EBP1 (Thr37/46) in both cell lines. Moreover, the examination of MAPK signaling pathway showed that PD treatment increased the phosphorylation of JNK and p38 MAPK, while decreased the phosphorylation of Erk1/2 in both cell lines. Additionally, the effects assessed with a panel of pharmacologic inhibitors, including U0126 (Erk1/2 kinase inhibitor), SP600125 (JNK kinase inhibitor) and SB203580 (p38 MAPK kinase inhibitor) suggested that the activation of JNK and p38 MAPK participated in PD-induced autophagy. Taken together, these findings suggested that PD induced autophagy in NCI-H460 and A549 cells through inhibiting PI3K/Akt/mTOR signaling pathway and activating JNK and p38 MAPK signaling pathways. Therefore, PD may be an alternative compound for NSCLC therapy.

Platycodin D induces apoptosis, and inhibits adhesion, migration and invasion in HepG2 hepatocellular carcinoma cells

BACKGROUND

Platycodin D (PD), a triterpenoid saponin isolated from the Chinese medicinal herb Platycodonis radix, possesses anti-cancer effects in several cancer cell lines. The aim of this study was to evaluate its anti- cancer activities in hepatocellular carcinoma cells.

MATERIALS AND METHODS

MTT and colony formation assays were performed to evaluate cell proliferation, along with flow cytometry and Western blotting for apoptosis. Cell adhesion was tested by observing cellular morphology under a microscope, while the transwell assay was employed to investigate the cell migration and invasion.

RESULTS

PD concentration-dependently inhibited cell proliferation in both HepG2 and Hep3B cells, and significantly suppressed colony formation and induced apoptosis in HepG2 cells. The protein levels of cleaved poly ADP-ribose polymerase (PARP) and Bax were up-regulated while that of survivin was down-regulated after treatment with PD. Moreover, PD not only obviously suppressed the adhesion of HepG2 cells to Matrigel, but also remarkably depressed their migration and invasion induced by 12-O-tetradecanoylphorbol 13-acetate (TPA).

CONCLUSIONS

PD presents anti-cancer potential in hepatocellular carcinoma cells via inducing apoptosis, and inhibiting cell adhesion, migration and invasion, indicating promising features as a lead compound for anti-cancer agent development.

Platycodin D from Platycodonis Radix enhances the anti-proliferative effects of doxorubicin on breast cancer MCF-7 and MDA-MB-231 cells

BACKGROUND

It has been demonstrated that platycodin D (PD) exhibits anti-cancer activities. This study aims to investigate the anti-proliferative effects of the combination of PD and doxorubicin (DOX) on human breast cancer cells (MCF-7 and MDA-MB-231 cells).

METHODS

The anti-proliferative effects of different dosages of PD, DOX, and PD + DOX on MCF-7 and MDA-MB-231 cells were determined by the MTT assay. The 10 μM PD, 5 μM DOX, and 10 μM PD + 5 μM DOX induced-protein expression of apoptosis-related molecules on MCF-7 and MDA-MB-231 cells were detected by western blot. The 10 μM PD, 5 μM DOX and 10 μM PD + 5 μM DOX-induced mitochondrial membrane potential changes on MCF-7 and MDA-MB-231 cells were stained with JC-1 before visual determination. The intracellular accumulations of DOX, induced by 10 μM PD, 5 μM DOX and 10 μM PD + 5 μM DOX, were detected by flow cytometry.

RESULTS

PD enhanced anti-cancer activities of DOX were observed in both MCF-7 and MDA-MB-231 cell lines. Compared with mono treatment, the combined treatment increased the protein expression of cleaved poly (ADP-ribose) polymerase and decreased the mitochondrial membrane potential. The combined treatment with PD did not obviously increase the accumulation of DOX in MCF-7 cells (1.66 ± 0.13 in DOX-treated group, and 1.69 ± 0.06 in PD + DOX-treated group, P = 0.76), but it significantly increased the accumulation of DOX in MDA-MB-231 cells (1.76 ± 0.17 in DOX-treated group, 2.09 ± 0.02 in PD + DOX-treated group, P = 0.027).

CONCLUSION

The combined treatment of DOX and PD exhibited stronger anti-proliferative effects on MCF-7 and MDA-MB-231 cells than DOX and PD treatment did.

The retroviral restriction ability of SAMHD1, but not its deoxynucleotide triphosphohydrolase activity, is regulated by phosphorylation

SAMHD1 is a cellular enzyme that depletes intracellular deoxynucleoside triphosphates (dNTPs) and inhibits the ability of retroviruses, notably HIV-1, to infect myeloid cells. Although SAMHD1 is expressed in both cycling and noncycling cells, the antiviral activity of SAMHD1 is limited to noncycling cells. We determined that SAMHD1 is phosphorylated on residue T592 in cycling cells but that this phosphorylation is lost when cells are in a noncycling state. Reverse genetic experiments revealed that SAMHD1 phosphorylated on residue T592 is unable to block retroviral infection, but this modification does not affect the ability of SAMHD1 to decrease cellular dNTP levels. SAMHD1 contains a target motif for cyclin-dependent kinase 1 (cdk1) ((592)TPQK(595)), and cdk1 activity is required for SAMHD1 phosphorylation. Collectively, these findings indicate that phosphorylation modulates the ability of SAMHD1 to block retroviral infection without affecting its ability to decrease cellular dNTP levels.

The Effects of Platycodin D, a Saponin Purified from Platycodi Radix, on Collagen-Induced DBA/1J Mouse Rheumatoid Arthritis

The object of this study is to observe the effects of platycodin D, a saponin purified from Platycodi Radix, on mice collagen-induced arthritis (CIA). A daily dose of 200, 100, and 50 mg/kg platycodin D was administered orally to male DBA/1J mice for 40 days after initial collagen immunization. To ascertain the effects administering the collagen booster, CIA-related features (including body weight, poly-arthritis, knee and paw thickness, and paw weight increase) was measured from histopathological changes in the spleen, left popliteal lymph node, third digit, and the knee joint regions. CIA-related bone and cartilage damage improved significantly in the platycodin D-administered CIA mice. Additionally, myeloperoxidase (MPO) levels in the paw were reduced in platycodin D-treated CIA mice compared to CIA control groups. The level of malondialdehyde (MDA), an indicator of oxidative stress, decreased in a dose-dependent manner in the platycodin D group. Finally, the production of IL-6 and TNF-α, involved in rheumatoid arthritis pathogenesis, was suppressed by treatment with platycodin D. Taken together, these results suggest that platycodin D is a promising new effective antirheumatoid arthritis agent, exerting anti-inflammatory, antioxidative and immunomodulatory effects in CIA mice.

Research Progress on Natural Triterpenoid Saponins in the Chemoprevention and Chemotherapy of Cancer

Triterpenoid saponins are glycosides with remarkable structural and bioactive diversity. They are becoming increasingly significant in the treatment of cancer due to their efficacy and safety. This chapter provides an update on the sources, pharmacological effects, structure-activity relationships, and clinical studies of anticancer triterpenoid saponins with a particular focus on the molecular mechanisms underlying their therapeutic properties. The correlative references and study reports described were collected through PubMed. The anticancer triterpenoid saponins enable the inhibition of cancer formation and progression by modulating multiple signaling targets related to cellular proliferation, apoptosis, autophagy, metastasis, angiogenesis, inflammation, oxidative stress, multidrug resistance, cancer stem cells, and microRNAs. This review provides new insights into the molecular basis of triterpenoid saponins in the chemoprevention and chemotherapy of cancer.

Evaluation of the spermicidal and contraceptive activity of Platycodin D, a Saponin from Platycodon grandiflorum

BACKGROUND

The extract of Platycodon grandiflorum has been reported to have effective spermicidal activity. This study was designed to evaluate the spermicidal and contraceptive activity, as well as the safety, of Platycodin D (PD), a major saponin in Platycodon grandiflorum.

METHODS

Using the computer-aided sperm analysis (CASA) test criteria, the sperm-immobilizing activity of PD was studied using highly motile human sperm. The sperm viability was assessed by fluorescent staining using SYBR-14 (living sperm) and propidium iodide (dead sperm). The sperm membrane integrity was assessed by evaluating the hypo-osmotic swelling (HOS) and examinations by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The in vivo contraceptive efficacy was evaluated in rats using post-intrauterine PD application. The comet assay was employed to determine whether PD caused DNA damage in the sperm. Vaginal biopsies were also performed to determine whether the PD gel induced vaginal inflammation.

RESULTS

A dose-dependent effect of PD on the sperm motility and viability was observed. The maximum spermicidal effect was observed with a 0.25 mM concentration of PD. More than 70% of the PD-treated sperm lost their HOS responsiveness at a concentration of 0.20 mM PD, indicating that PD caused injury to the sperm plasma membrane. TEM and SEM revealed significant damage to both the head and tail membranes of the sperm. PD decreased the fertility to zero in rats, was non-DNA damaging and was not harmful to the vaginal tissue in the rats.

CONCLUSION

PD has significant spermicidal activity that should be explored in further studies.

Single oral dose toxicity test of platycodin d, a saponin from platycodin radix in mice

The object of this study was to evaluate the single oral dose toxicity of platycodin D, a saponin from the root of Platycodon grandiflorum in male and female mice. Platycodin D was administered to female and male mice as an oral dose of 2000, 1000, 500, 250 and 125 mg/kg (body wt.). Animals were monitored for the mortality and changes in body weight, clinical signs and gross observation during 14 days after treatment, upon necropsy, organ weight and histopathology of 14 principle organs were examined. As the results, no platycodin D treatment related mortalities, clinical signs, changes on the body and organ weights, gross and histopathological observations against 14 principle organs were detected up to 2000 mg/kg in both female and male mice. Therefore, LD₅₀ (50% lethal dose) and approximate LD of playtcodin D after single oral treatment in female and male mice were considered over 2000 mg/kg - the limited dosages recommended by KFDA Guidelines [2009-116, 2009], respectively.

Oldhamianoside II, a new triterpenoid saponin, prevents tumor growth via inducing cell apoptosis and inhibiting angiogenesis

Oldhamianoside II is a new triterpenoid saponin that was isolated from the roots of Gypsophila oldhamiana. The present study aims to investigate the potential inhibitory activity of oldhamianoside II on tumor growth using an S180 tumor implantation mouse model. Oldhamianoside II at doses of 5.0 and 10.0 mg/kg was given with intraperitoneal injection for 10 days following subcutaneous inoculation of S180 tumor cells in anterior flank of mice. The tumor growth, the cell apoptosis, the microvessel density (MVD) in S180 tumors, the tumor cell viability, the tubular formation in vitro, and migration of tumor cells were examined. The expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and cyclooxygenase-2 (COX-2) was determined to analyze the associated mechanisms. The results showed that oldhamianoside II potently inhibited tumor cell viability in vitro. In addition, oldhamianoside II delayed tumor growth in anterior flank, induced S180 cell apoptosis, and reduced the MVD. Oldhamianoside II was also demonstrated to decrease the number of tubular structure and vessel formation in HUVEC cultures and chick embryo chorioallantoic membrane (CAM) model, respectively. Further study indicated that oldhamianoside II reduced the expression of VEGF, bFGF, and COX-2 in tumor sections. Moreover, oldhamianoside II inhibited the activity of migration and penetration to Matrigel of SGC7901 tumor cells in scratch wound and transwell chamber. In conclusion, our work defines oldhamianoside II, a new triterpenoid saponin, as a novel compound that can effectively inhibit S180 tumor growth, induce tumor cell apoptosis, prevent tumor angiogenesis, and inhibit cancer cell migration, suggesting that oldhamianoside II is a potential drug candidate for the treatment of cancer and for the prevention of metastasis.

Platycodin D induces apoptosis in MCF-7 human breast cancer cells

Platycodin D (PD), a major constituent isolated from the root of Platycodon grandiflorum, has been suggested to possess anticancer activities, as indicated by its capabilities to induce mitotic arrest and apoptosis in several cancer cells. However, little is known of the underlying action mechanism. This study is the first to investigate the anticancer effect of PD in the human breast cancer cell, MCF-7. Our data showed that PD exhibited marked cell growth inhibition by inducing apoptosis. This induction was associated with activation of caspase-8 and -9 activities and poly(ADP-ribose) polymerase. PD triggered the mitochondrial apoptotic pathway, as indicated by up-regulation of levels of cellular Bax and down-regulation of levels of Bcl-2 and caspase-9 activation. We found that PD induced proteolytic activation of Bid, a member of the proapoptotic Bcl-2 family, implicating PD-induced apoptosis as possibly being functionally linked to a death receptor-mediated pathway. The PD treatment also was accompanied by an increase in cellular generation of reactive oxygen species, indicating that PD-induced apoptosis is likely to be mediated through mitochondrial dysfunction. In addition, we revealed that the mitogen-activated protein kinases, including extracellular signal-regulated kinase 1/2, c-Jun NH(2)-terminal kinase 1/2, and p38, which play important roles in apoptosis, were activated by treatment with PD. These results provide a basic mechanism for the anticancer properties of PD and suggest that PD is a promising candidate for chemotherapy and chemoprevention of breast cancer.

Chemical study and medical application of saponins as anti-cancer agents

Saponins are a group of naturally occurring plant glycosides, characterized by their strong foam-forming properties in aqueous solution. The presence of saponins has been reported in more than 100 families of plants out of which at least 150 kinds of natural saponins have been found to possess significant anti-cancer properties. There are more than 11 distinguished classes of saponins including dammaranes, tirucallanes, lupanes, hopanes, oleananes, taraxasteranes, ursanes, cycloartanes, lanostanes, cucurbitanes and steroids. Due to the great variability of their structures, saponins always display anti-tumorigenic effects through varieties of antitumor pathways. In addition, there are a large amount of saponins that still either remain to be trapped or studied in details by the medicinal chemists. This article reviews many such structures and their related chemistry along with the recent advances in understanding mechanism of action and structure-function relationships of saponins at the molecular and cellular levels. These aglycones have been described and their classification and distribution have been listed in the review. Some special saponins with strong antitumor effects have also been exhibited. Ginsenosides, belonging to dammaranes, have been found beneficial targeted on inhibition of tumor angiogenesis by suppressing its inducer in the endothelial cells of blood vessels, and then on prevention of adhering, invasion, and metastasis of tumor cells. Dioscin, one of the steroidal saponins, and its aglycone diosgenin also have been extensively studied on its antitumor effect by cell cycle arrest and apoptosis. Other important molecules discussed include oleanane saponins such as avicins, platycodons, saikosaponins, and soysaponins along with tubeimosides.

Arylthioindoles: Promising compounds against cancer cell proliferation

Drugs that are able to modulate the microtubule dynamics either by inhibiting tubulin polymerization or by blocking microtubule disassembly are of great interest in anti-cancer therapy; a number of them are currently applied in clinical development. Tubulin polymerization inhibitors, including arylthioindoles, are characterized by the presence of an indole nucleus and have been obtained from natural sources or prepared by semi-synthesis. We characterized the effect of 5-bromo-3-[(3,4,5-trimetoxyphenyl)thio]-1H-indole (RS 2518) on the metabolism of human cell lines derived from solid tumors. We found that this new compound impairs cell adhesion, arrests the cells in the G(2)/M cell cycle phase and inhibits cell proliferation, thus leading to apoptosis. The described effects of RS 2518 on cancer cells have led to its selection as a lead compound for further studies. Some analogues have been developed and tested on a panel of cancer cell lines.

Inhibitory effect of saponin fraction from Codonopsis lanceolata on immune cell-mediated inflammatory responses

Saponin components are known to be pharmaceutically, cosmetically and nutraceutically valuable principles found in various herbal medicine. In this study, we evaluated the inhibitory role of saponin fraction (SF), prepared from C. lanceolata, an ethnopharmacologically famous plant, on various inflammatory responses managed by monocytes, macrophages, lymphocytes and mast cells. SF clearly suppressed the release of nitric oxide (NO) and tumor necrosis factor (TNF)-alpha, but not prostaglandin E(2) (PGE(2)). While this fraction did not scavenge the reactivity of SNP-induced radicals in RAW264. 7 cells, it negatively modulated the phagocytic uptake of macrophages treated with FITC-dextran. Interestingly, SF completely diminished cell-cell adhesion events induced by both CD29 and CD43, but not cell-fibronectin adhesion. Concanavalin (Con) A [as well phytohemaglutinin A (PHA)]-induced proliferation of splenic lymphocytes as well as interferon (IFN)-gamma production were also clearly suppressed by SF treatment. Finally, SF also significantly blocked the degranulation process of mast cell line RBL-2H3 cell as assessed by DNP-BSA-induced beta-hexosaminidase activity. The anti-inflammatory activities of SF on NO production seemed to be due to inhibition of nuclear factor (NF)-kappaB activation signaling, since it blocked the phosphorylation of inhibitor of kappaB (IkappaB)alpha as well as inducible NO synthase (iNOS) expression. Therefore, these results suggest that SF may be considered as a promising herbal medicine with potent anti-inflammatory actions.

P38MAPK regulates caspase-3 by binding to caspase-3 in nucleus of human hepatoma Bel-7402 cells during anti-Fas antibody- and actinomycin D-induced apoptosis

Anti-Fas antibody- and actinomycin D (FA/AD) has been shown to have anti-tumor activity in some tumor cells. However, many of the molecular mechanism of FA/AD-induced apoptosis of human hepatoma Bel-7402 cells have not been fully clarified. In the present study, therefore, the effect of FA/AD in presence or absence of p38MAPK inhibitor SB203580 on the proliferation, apoptosis, p38MAPK, caspase-3, location of p38MAPK and caspase-3, and interaction between p38MAPK and caspase-3 in Bel-7402 cell was investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT), annexin V-FITC/propidium iodide (PI) double staining, electron microscopy, immunoblot, immunofluorescence and immunoprecipitation/immunoblot assay, respectively. We found that FA/AD significantly resulted in the inhibition of proliferation, induction of apoptosis, activation and up-regulation of p38MAPK, activation and up-regulation of caspase-3, translocation of p38MAPK and caspase-3 from cytosol to nucleus, and formation of p38MAPK/caspase-3 complex in Bel-7402 cells. In contrast, SB203580, a p38MAPK-specific inhibitor, apparently blocked induction of apoptosis, activation and up-regulation of p38MAPK, activation and up-regulation of caspase-3, and translocation of p38MAPK and caspase-3 from cytosol to nucleus in FA/AD-treated Bel-7402 cells. Taken together, we conclude that p38MAPK regulates caspase-3 by binding to caspase-3 in nucleus of Bel-7402 cells during FA/AD-induced apoptosis.