Tetrandrine inhibits activation of rat hepatic stellate cells stimulated by transforming growth factor-beta in vitro via up-regulation of Smad 7

Tetrandrine: a review of its anticancer potentials, clinical settings, pharmacokinetics and drug delivery systems

OBJECTIVES

Tetrandrine, a natural bisbenzylisoquinoline alkaloid, possesses promising anticancer activities on diverse tumours. This review provides systematically organized information on cancers of tetrandrine in vivo and in vitro, discuss the related molecular mechanisms and put forward some new insights for the future investigations.

KEY FINDINGS

Anticancer activities of tetrandrine have been reported comprehensively, including lung cancer, colon cancer, bladder cancer, prostate cancer, ovarian cancer, gastric cancer, breast cancer, pancreatic cancer, cervical cancer and liver cancer. The potential molecular mechanisms corresponding to the anticancer activities of tetrandrine might be related to induce cancer cell apoptosis, autophagy and cell cycle arrest, inhibit cell proliferation, migration and invasion, ameliorate metastasis and suppress tumour cell growth. Pharmaceutical applications of tetrandrine combined with nanoparticle delivery system including liposomes, microspheres and nanoparticles with better therapeutic efficiency have been designed and applied encapsulate tetrandrine to enhance its stability and efficacy in cancer treatment.

SUMMARY

Tetrandrine was proven to have definite antitumour activities. However, the safety, bioavailability and pharmacokinetic parameter studies on tetrandrine are very limited in animal models, especially in clinical settings. Our present review on anticancer potentials of tetrandrine would be necessary and highly beneficial for providing guidelines and directions for further research of tetrandrine.

Targeting Hepatic Stellate Cells for the Treatment of Liver Fibrosis by Natural Products: Is It the Dawning of a New Era?

Liver fibrosis is a progressive liver damage condition that is worth studying widely. It is important to target and alleviate the disease at an early stage before turning into later cirrhosis or liver cancer. There are currently no direct medicines targeting the attenuation or reversal of liver fibrosis, and so there is an urgent need to look into this area. Traditional Chinese Medicine has a long history in using herbal medicines to treat liver diseases including fibrosis. It is time to integrate the ancient wisdom with modern science and technology to look for the best solution to the disease. In this review, the principal concept of the pathology of liver fibrosis will be described, and then some of the single compounds isolated from herbal medicines, including salvianolic acids, oxymatrine, curcumin, tetrandrine, etc. will be discussed from their effects to the molecular mechanism behind. Molecular targets of the compounds are analyzed by network pharmacology approach, and TGFβ/SMAD was identified as the most common pathway. This review serves to summarize the current findings of herbal medicines combining with modern medicines in the area of fibrosis. It hopefully provides insights in further pharmaceutical research directions.

Identification of Hepatoprotective Constituents in Limonium tetragonum and Development of Simultaneous Analysis Method using High-performance Liquid Chromatography

Background:

Limonium tetragonum, a naturally salt-tolerant halophyte, has been studied recently and is of much interest to researchers due to its potent antioxidant and hepatoprotective activities.

Objective:

In the present study, we attempted to elucidate bioactive compounds from ethyl acetate (EtOAc) soluble fraction of L. tetragonum extract. Furthermore, the simultaneous analysis method of bioactive EtOAc fraction of L. tetragonum has been developed using high-performance liquid chromatography (HPLC).

Materials and Methods:

Thirteen compounds have been successfully isolated from EtOAc fraction of L. tetragonum, and the structures of 1–13 were elucidated by extensive one-dimensional and two-dimensional spectroscopic methods including ¹H-NMR, ¹³C-NMR, ¹H-¹H COSY, heteronuclear single quantum coherence, heteronuclear multiple bond correlation, and nuclear Overhauser effect spectroscopy. Hepatoprotection of the isolated compounds against liver fibrosis was evaluated by measuring inhibition on hepatic stellate cells (HSCs) undergoing proliferation.

Results:

Compounds 1–13 were identified as gallincin (1), apigenin-3-O-β-D-galactopyranoside (2), quercetin (3), quercetin-3-O-β-D-galactopyranoside (4), (−)-epigallocatechin (5), (−)-epigallocatechin-3-gallate (6), (−)-epigallocatechin-3-(3″-O-methyl) gallate (7), myricetin-3-O-β-D-galactopyranoside (8), myricetin-3-O-(6″-O-galloyl)-β-D-galactopyranoside (9), myricetin-3-O-α-L-rhamnopyranoside (10), myricetin-3-O-(2″-O-galloyl)-α-L-rhamnopyranoside (11), myricetin-3-O-(3″-O-galloyl)-α-L-rhamnopyranoside (12), and myricetin-3-O-α-L-arabinopyranoside (13), respectively. All compounds except for 4, 8, and 10 are reported for the first time from this plant.

Conclusion:

Myricetin glycosides which possess galloyl substituent (9, 11, and 12) showed most potent inhibitory effects on the proliferation of HSCs.

SUMMARY

In the present study, we have successfully isolated 13 compounds from bioactive fraction of Limonium tetragonum. The structures of compounds isolated have been fully elucidated, and hepatoprotective activities of compounds against liver fibrosis were evaluated by measuring inhibition on hepatic stellate cells undergoing proliferation. Furthermore, the simultaneous analysis method of bioactive ethyl acetate fraction of L. tetragonum has been developed using HPLC. Ten compounds identified herein are reported for the first time from this plant.

Abbreviations used: HSQC: Heteronuclear single quantum coherence; HMBC: Heteronuclear multiple bond correlation; NOESY: Nuclear Overhauser effect spectroscopy; EGCG: Epigallocatechin-3-gallate; EGC: Epigallocatechin; HSC: Hepatic stellate cell; MTT: 3-(4,5-dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide.

Tetrandrine induces lipid accumulation through blockade of autophagy in a hepatic stellate cell line

Macroautophagy, or autophagy, is a cellular response in which unnecessary cytoplasmic components, including lipids and organelles, are self-degraded. Recent studies closely related autophagy to activation of hepatic stellate cells (HSCs), a process critical in the pathogenesis of liver fibrosis. During HSC activation, cytoplasmic lipid droplets (LDs) are degraded as autophagic cargo, and then cells express fibrogenic genes. Thus, inhibition of autophagy in HSCs is a potential therapeutic approach for attenuating liver fibrosis. We found that tetrandrine, a bisbenzylisoquinoline alkaloid isolated from Stephania tetrandra, induced lipid accumulation, a phenotype associated with quiescent HSCs, through blockade of autophagy in the rat-derived HSC line HSC-T6. Tetrandrine inhibited autophagic flux without affecting lysosomal function. A phenotypic comparison using siRNA knockdown suggested that tetrandrine may target regulators, involved in fusion between autophagosomes and lysosomes (e.g., syntaxin 17). Moreover, perilipin 1, an LD-coated protein, co-localized specifically with LC3, a marker protein for autophagosomes, in tetrandrine-treated HSC-T6 cells. This suggests a potential role for perilipin 1 in autophagy-mediated LD degradation in HSCs. Our results identified tetrandrine as a potential tool for prevention and treatment of HSC activation.

Antifibrotic compounds from Liriodendron tulipifera attenuating HSC-T6 proliferation and TNF-α production in RAW264.7 cells

The inhibition of hepatic stellate cell (HSC) proliferation has been considered as an effective therapeutic target for the treatment of liver fibrosis. The methanolic extract of Liriodendron tulipifera showed significant inhibitory activity against the proliferation of HSCs. Bioactivity-guided isolation afforded twelve compounds including (-)-sesamin (1), (-)-syringaresinol (2), (+)-dihydrodehydrodiconiferyl alcohol (3), salvinal (4), (+)-guaiacylglycerol-8-O-4'-dihydroconiferyl ether (5), (±)-guaiacylglycerol-8-O-4'-sinapyl alcohol ether (6), tanegool (7), (+)-5,5'-dimethoxy-7-oxolariciresinol (8), 3-hydroxy-4-methoxyacetophenone (9), 4-acetoxymethylphenol (10), (-)-paramicholide (11), and blumenol A (12). Among the compounds isolated, 2, 3 and 4 significantly attenuated the proliferation of the activated HSC-T6 cells. The maximal dose of these compounds, however, showed no cytotoxicity in primary cultured rat hepatocytes. Collagen deposition in the activated HSC-T6 cells was reduced by 2, 3 and 4. Also, the increased production of the pro-inflammatory cytokine tumor necrosis factor (TNF)-α induced by lipopolysaccharide was decreased by 3 and 4 in RAW264.7 macrophage cells. Collectively, (-)-syringaresinol (2), (+)-dihydrodehydrodiconiferyl alcohol (3), and salvinal (4) isolated from L. tulipifera leaves and twigs exhibited selective antifibrotic activities toward the activated HSCs and suppressed TNF-α production in RAW264.7 macrophages. These compounds may be useful candidates for developing therapeutic agents for the prevention and treatment of hepatic fibrosis.

Hepatoprotective effects of Limonium tetragonum, edible medicinal halophyte growing near seashores

Background:

During the process of hepatic fibrosis, the activation of hepatic stellate cells (HSCs) is responsible for the increased formation and reduced degradation of extracellular matrix in the liver. By employing the hepatic stellate cell line, HSC-T6, it was found that the methanol extract of Limonium tetragonum, a halophyte living in salt marsh near south and western seashores of Korea significantly inhibited the proliferation of HSC-T6 cells.

Objective:

In the present study, we attempted to investigate the antifibrotic effects of the mathanolic extract of L. tetragonum (MELT) in the activated HSC-T6 cells.

Materials and Methods:

The proliferation of HSC-T6 was stimulated by culturing environment or platelet-derived growth factor (PDGF-BB) insult, and then the inhibitory activities of MELT were measured.

Results:

It was found that MELT suppressed the proliferation of the activated HSC-T6 in concentration- and time-dependent manners. The increased collagen deposition in the activated HSC-T6 cells was also decreased by the treatment of MELT. The maximal dose of MELT, however, had little effect on primary cultured rat hepatocytes. Wlammatory cytokine, tumor necrosis factor alpha (TNF-α) produced by lipopolysaccharide-stimulated RAW264.7 macrophages was inhibited by MELT.

Conclusion:

Collectively, the above results demonstrated that MELT suppressed HSCs proliferation but not in hepatocytes, implying that L. tetragonum may be useful candidates for developing therapeutic agents for the prevention and treatment of hepatic fibrosis.

Precision-cut liver slices as a model for the early onset of liver fibrosis to test antifibrotic drugs

Induction of fibrosis during prolonged culture of precision-cut liver slices (PCLS) was reported. In this study, the use of rat PCLS was investigated to further characterize the mechanism of early onset of fibrosis in this model and the effects of antifibrotic compounds. Rat PCLS were incubated for 48h, viability was assessed by ATP and gene expression of PDGF-B and TGF-β1 and the fibrosis markers Hsp47, αSma and Pcol1A1 and collagen1 protein expressions were determined. The effects of the antifibrotic drugs imatinib, sorafenib and sunitinib, PDGF-pathway inhibitors, and perindopril, valproic acid, rosmarinic acid, tetrandrine and pirfenidone, TGFβ-pathway inhibitors, were determined. After 48h of incubation, viability of the PCLS was maintained and gene expression of PDGF-B was increased while TGF-β1 was not changed. Hsp47, αSma and Pcol1A1 gene expressions were significantly elevated in PCLS after 48h, which was further increased by PDGF-BB and TGF-β1. The increased gene expression of fibrosis markers was inhibited by all three PDGF-inhibitors, while TGFβ-inhibitors showed marginal effects. The protein expression of collagen 1 was inhibited by imatinib, perindopril, tetrandrine and pirfenidone. In conclusion, the increased gene expression of PDGF-B and the down-regulation of fibrosis markers by PDGF-pathway inhibitors, together with the absence of elevated TGF-β1 gene expression and the limited effect of the TGFβ-pathway inhibitors, indicated the predominance of the PDGF pathway in the early onset of fibrosis in PCLS. PCLS appear a useful model for research of the early onset of fibrosis and for testing of antifibrotic drugs acting on the PDGF pathway.

Sesquiterpene lactones from the roots of Lindera strychnifolia

Phytochemical investigation of the roots of Lindera strychnifolia resulted in the isolation of seven sesquiterpene lactones named linderolide G-M (1-7), together with twelve known sesquiterpenes. The structures and relative configurations of 1-7 were determined through spectroscopic observations, and the absolute configurations were defined by CD analysis. Linderolide G (1) and lindestrene (16) showed cytotoxicity against HSC-T6 hepatic stellate cells.

Antifibrotic effect of N-acetyl-seryl-aspartyl-lysyl-proline on bile duct ligation induced liver fibrosis in rats

AIM: To investigate the preventive effect of N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) on bile duct ligation (BDL)-induced liver fibrosis in rats.

METHODS: Liver fibrosis in rats was induced by BDL and AcSDKP was infused subcutaneously for 2 wk via a osmotic minipump (Alzet 2ML4) immediately after BDL operation. After scarifying, serum and liver specimens were collected. Hematoxylin and eosin staining, Sirius red staining, enzyme linked immunosorbent assay, Western blot or real-time polymerase chain reaction were used to determinate liver functions, histological alterations, collagen deposition, mRNA expression of markers for fibroblasts, transforming growth factor-β1 (TGF-β1) and bone morphogenetic protein-7 (BMP-7).

RESULTS: When compared to model rats, chronic exogenous AcSDKP infusion suppressed profibrogenic TGF-β1 signaling, α-smooth muscle actin positivity (α-SMA), fibroblast specific protein-1 (FSP-1) staining and collagen gene expression. Col I, Col III, matrix metalloproteinase-2, tissue inhibitors of metalloproteinase-1 and tissue inhibitors of metalloproteinase-2 mRNA expressions were all significantly downregulated by AcSDKP infusion (2.02 ± 1.10 vs 14.16 ± 6.50, 2.02 ± 0.45 vs 10.00 ± 3.35, 2.91 ± 0.30 vs 7.83 ± 1.10, 4.64 ± 1.25 vs 18.52 ± 7.61, 0.46 ± 0.16 vs 0.34 ± 0.12, respectively, P < 0.05). Chronic exogenous AcSDKP infusion attenuated BDL-induced liver injury, inflammation and fibrosis. BDL caused a remarkable increase in alanine transaminase, aspartate transaminase, total bilirubin, and prothrombin time, all of which were reduced by AcSDKP infusion. Mast cells, collagen accumulation, α-SMA, TGF-β1, FSP-1 and BMP-7 increased. The histological appearance of liver specimens was also improved.

CONCLUSION: Infusion of exogenous AcSDKP attenuated BDL-induced fibrosis in the rat liver. Preservation of AcSDKP may be a useful therapeutic approach in the management of liver fibrosis.

Role of chymase in the pathogenesis of experimental liver fibrosis in rats

AIM: To investigate the role of chymase in the pathogenesis of dimethylnitrosamine (DMN)-induced liver fibrosis in rats.

METHODS: Thirty male Wistar rats were randomly divided into three groups. The model group was administered with 10% DMN. The interventional group was given soybean trypsin inhibitor (SBTI) after induction of liver fibrosis with DMN. The normal group was given normal sodium. Liver histological and ultramicroscopic changes were observed, and serum indices for liver fibrosis, serum transforming growth factor β1 (TGF-β1) and hepatic chymase-like activity were measured at the end of the experiment.

RESULTS: Compared to the model group, the interventional group had narrower fiber separation and showed no typical pseudo-lobule. Transmission electron microscopy demonstrated that hepatic cell damage in the interventional group was lessened significantly as compared to that in the model group, and only scattered collagen fiber was observed in the sinus hepaticus. Serum levels of HA, LN, PC III, C IV, TGF-β1 and hepatic chymase-like activity in the interventional group were significantly lower than those in the model group (all P < 0.05).

CONCLUSION: Chymase participates in the development of liver fibrosis possibly by direct or indirect induction of TGF-β1 and may be a promising therapy target for hepatic fibrosis.

Cortex Dictamni extract induces apoptosis of activated hepatic stellate cells via STAT1 and attenuates liver fibrosis in mice

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional Chinese medicines, Cortex Dictamni is prescribed for the treatment of a variety of inflammatory diseases such as acute rheumatoid arthritis, skin inflammation and jaundice.

AIM OF THE STUDY

This study was designed to investigate the effect of ethanol extract of Cortex Dictamni on treatment of hepatic fibrosis and its possible mechanisms.

MATERIALS AND METHODS

The in vivo effect of Cortex Dictamni extract (CDE) was evaluated by measuring histological changes and collagen content in CCl(4)-indcued hepatic fibrosis mice. Viability, apoptosis and protein expression of hepatic stellate cells (HSC) were analyzed by MTT, Annexin V staining and Western blot respectively.

RESULTS

CDE alleviated CCl(4)-induced hepatic fibrosis in mice and showed a much stronger inhibition of cell viability in activated HSC cell line HSC-T6 than that in normal hepatocyte L02 cells. Furthermore, CDE induced apoptosis of HSC-T6 cells associated with increased expressions of cleaved PARP and cleaved caspase-3. Interestingly, CDE activated STAT1 in HSC-T6 cells and the effect of CDE on apoptosis of HSC-T6 cells could be neutralized using JAK/STAT1 signaling inhibitor AG490.

CONCLUSIONS

These findings suggest that CDE possesses anti-fibrosis activity with selectively induction of activated HSC apoptosis via activating STAT1, which might be a novel strategy for hepatic fibrosis therapy.

The genus Stephania (Menispermaceae): chemical and pharmacological perspectives

The plants of the genus Stephania (Menispermaceae) are widely distributed, and have long been used in folk medicine for the treatment of various ailments such as asthma, tuberculosis, dysentery, hyperglycemia, malaria, cancer and fever. Over 150 alkaloids together with flavonoids, lignans, steroids, terpenoids and coumarins have been identified in the genus, and many of these have been evaluated for biological activity. This review presents comprehensive information on the chemistry and pharmacology of the genus together with the traditional uses of many of its plants. In addition, this review discusses the structure-activity relationship of different compounds as well as recent developments and the scope for future research in this aspect.

Prevention of in vitro hepatic stellate cells activation by the adenosine derivative compound IFC305

We have previously shown that adenosine and the aspartate salt of adenosine (IFC305) reverse pre-established CCl(4)-induced cirrhosis in rats. However, their molecular mechanism of action is not clearly understood. Hepatic stellate cells (HSC) play a pivotal role in liver fibrogenesis leading to cirrhosis, mainly through their activation, changing from a quiescent adipogenic state to a proliferative myofibrogenic condition. Therefore, we decided to investigate the effect of IFC305 on primary cultured rat HSC. Our results reveal that this compound suppressed the activation of HSC, as demonstrated by the maintenance of a quiescent cell morphology, including lipid droplets content, inhibition of α-smooth muscle actin (α-SMA) and collagen α1(I) expression, and up-regulation of MMP-13, Smad7, and PPARγ expression, three key antifibrogenic genes. Furthermore, IFC305 was able to repress the platelet-derived growth factor (PDGF)-induced proliferation of HSC. This inhibition was independent of adenosine receptors stimulation; instead, IFC305 was incorporated into cells by adenosine transporters and converted to AMP by adenosine kinase. On the other hand, addition of pyrimidine ribonucleoside as uridine reversed the suppressive effect of IFC305 on the proliferation and activation of HSC, suggesting that intracellular pyrimidine starvation would be involved in the molecular mechanism of action of IFC305. In conclusion, IFC305 inhibits HSC activation and maintains their quiescence in vitro; these results could explain in part the antifibrotic liver beneficial effect previously described for this compound on the animal model.

Preservation of basal AcSDKP attenuates carbon tetrachloride-induced fibrosis in the rat liver

BACKGROUND & AIMS

N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) is an endogenous tetrapeptide which has antifibrogenic effects at physiological concentrations in various tissues. AcSDKP is produced locally in the liver, however, little is known about its biological effect in this organ. We hypothesize that basal levels of endogenous AcSDKP decrease during the development of liver fibrosis and preservation of basal AcSDKP attenuates liver fibrosis.

METHODS

Endogenous levels of AcSDKP in the liver were measured by enzyme immunoassay after 2, 6, and 10 weeks of carbon tetrachloride (CCl(4))-induced liver fibrosis in rats. Subcutaneous osmotic pump infusion of vehicle or AcSDKP (800 microg/kg/day) was administered to CCl(4)-treated rats for 8 weeks to study the effect of exogenous AcSDKP on liver fibrosis. The effect of AcSDKP on profibrogenic properties of hepatic stellate cells was studied in vitro.

RESULTS

Endogenous AcSDKP was significantly decreased in the liver of CCl(4)-treated rats. Chronic AcSDKP infusion preserved basal levels of AcSDKP and reduced liver injury, inflammation, fibrosis, and profibrogenic transforming growth factor-beta signaling. This was demonstrated by decreased aminotransferase serum levels, CD45 positive cells, collagen accumulation, alpha-smooth muscle actin positivity, transforming growth factor-beta1, phosphorylated Smad2/3 protein, increased bone morphogenetic protein-7, and phosphorylated Smad1/5/8. Further, AcSDKP exerts antifibrogenic effects on hepatic stellate cells (HSCs) by downregulation of HSC activation in vitro.

CONCLUSIONS

Maintaining physiological levels of AcSDKP is critical in negatively regulating the development of fibrosis in chronic liver injury. Preservation of AcSDKP may be a useful therapeutic approach in the management of liver fibrosis.

Role of small ubiquitin-related modifier-1 in the pathogenesis of hepatic fibrosis in rats

AIM: To observe the changes in the expression of small ubiquitin-related modifier-1 (SUMO-1) during the formation of hepatic fibrosis in rats and to investigate the role of SUMO-1 in the pathogenesis of hepatic fibrosis.

METHODS: Ninety male Sprague-Dawley rats were divided into two groups: model group and control group. The model group was subcutaneously injected with 40% carbon tetrachloride at a dose of 0.3 mL/100 g of body weight, while the control group was given equivalent volume of normal saline. Liver tissue samples were taken at weeks 2, 4, 6, 8, 10 and 12 after carbon tetrachloride injection. Hepatic fibrosis was pathologically evaluated. The expression of SUMO-1 mRNA and protein in liver tissue was detected by RT-PCR and Western blot, respectively.

RESULTS: During the formation of hepatic fibrosis, the expression of SUMO-1 mRNA was gradually up-regulated from week 2 to 12 (0.725 ± 0.017, 0.786 ± 0.018, 0.803 ± 0.023, 0.831 ± 0.020, 0.863 ± 0.016 and 0.892 ± 0.008, respectively; P < 0.01). Similarly, SUMO-1 protein expression was also gradually up-regulated from week 2 to 12 (0.810 ± 0.059, 0.873 ± 0.049, 0.923 ± 0.055, 0.959 ± 0.032, 0.988 ± 0.011 and 0.998 ± 0.004, respectively; P < 0.01).

CONCLUSION: The expression of both SUMO-1 mRNA and protein is gradually up-regulated during the formation of hepatic fibrosis, suggesting an important role of SUMO-1 in the pathogenesis of hepatic fibrosis.

Connection between inflammation and carcinogenesis in gastrointestinal tract: Focus on TGF-β signaling

Inflammation is a primary defense process against various extracellular stimuli, such as viruses, pathogens, foods, and environmental pollutants. When cells respond to stimuli for short periods of time, it results in acute or physiological inflammation. However, if the stimulation is sustained for longer time or a pathological state occurs, it is known as chronic or pathological inflammation. Several studies have shown that tumorigenesis in the gastrointestinal (GI) tract is closely associated with chronic inflammation, for which abnormal cellular alterations that accompany chronic inflammation such as oxidative stresses, gene mutations, epigenetic changes, and inflammatory cytokines, are shared with carcinogenic processes, which forms a critical cross-link between chronic inflammation and carcinogenesis. Transforming growth factor (TGF)-β is a multi-potent cytokine that plays an important role in regulation of cell growth, apoptosis and differentiation. Most importantly, TGF-β is a strong anti-inflammatory cytokine that regulates the development of effector cells. TGF-β has a suppressive effect on carcinogenesis under normal conditions by inhibiting abnormal cell growth, but on the other hand, many GI cancers originate from uncontrolled cell growth and differentiation by genetic loss of TGF-β signaling molecules or perturbation of TGF-β adaptors. Once a tumor has developed, TGF-β exerts a promoting effect on the tumor itself and stromal cells to enhance cell growth, alter the responsiveness of tumor cells to stimulate invasion and metastasis, and inhibited immune surveillance. Therefore, novel development of therapeutic agents to inhibit TGF-β-induced progression of tumor and to retain its growth inhibitory activities, in addition to anti-inflammatory actions, could be useful in oncology. In this review, we discuss the role of TGF-β in inflammation and carcinogenesis of the GI tract related to abnormal TGF-β signaling.

Proanthocyanidin derived from the leaves of Vaccinium virgatum suppresses platelet-derived growth factor-induced proliferation of the human hepatic stellate cell line LI90

AIM

Hepatic stellate cell (HSC) proliferation plays a pivotal role in liver fibrogenesis, and agents that suppress HSC activation, including platelet-derived growth factor (PDGF)-induced HSC proliferation, are good candidates for antifibrogenic therapies. In this report, we use the LI90 HSC line to elucidate the antifibrogenic effects of proanthocyanidin derived from the leaves of Vaccinium virgatum.

METHODS

Proanthocyanidin (PAC) was extracted from the leaves of blueberry V. virgatum (BB-PAC), grape seeds (GS-PAC) and Croton lechleri (CL-PAC). These extracts were examined for their effects on PDGF-BB-induced LI90 cell proliferation and DNA synthesis. Extracellular signal-regulated kinase (ERK) and Akt phosphorylation and PDGF receptor-beta (PDGFR-beta) expression were evaluated by western blot analysis.

RESULTS

BB-PAC potently suppressed PDGF-BB-induced proliferation and DNA synthesis of LI90 cells. BB-PAC also suppressed PDGF-BB-induced DNA synthesis in primary cultured rat HSC. Moreover, GS-PAC and CL-PAC suppressed PDGF-BB-induced DNA synthesis in LI90 cells. In contrast, the monomeric PAC catechin and epicatechin and dimeric PAC procyanidin B2 only slightly suppressed PDGF-BB-induced DNA synthesis. Western blot analysis showed that BB-PAC completely or partially inhibited PDGF-BB-induced ERK and Akt phosphorylation, respectively. In addition, BB-PAC partially inhibited the PDGF-BB-induced degradation of PDGFR-beta.

CONCLUSION

Our results suggest that BB-PAC suppresses activated HSC by inhibiting the PDGF signaling pathway. In addition, these results provide novel findings that may facilitate the development of antifibrogenic agents.

Smad7 overexpression inhibits TGF-β1-stimulated procollagen α1 (III) expression in cultured hepatic stellate cells

AIM: To investigate the effects of Smad7 overexpression on transforming growth factor-β1 (TGF-β1)-stimulated procollagen α1 (III) expression in cultured hepatic stellate cells (HSC-T6).

METHODS: Cultured HSC-T6 cells were divided into six groups: normal control group, TGF-β1 group, vehicle plasmid group, Smad7 plasmid group, TGF-β1 plus vehicle plasmid group, and TGF-β1 plus Smad7 plasmid group. Smad7 plasmid and vehicle plasmid were transfected into HSC-T6 cells with FuGENE 6 Reagent. Forty-eight hours after transfection, the expression level of procollagen α1 (III) mRNA was determined by reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-PCR.

RESULTS: Compared with the normal control group and the vehicle plasmid group, the expression levels of Smad7 mRNA increased significantly in the Smad7 plasmid group and the TGF-β1 plus Smad7 plasmid group (t = 59.43, 59.41, 54.27 and 54.25, respectively; all t > t_0.01 and all P < 0.01). Although there were no significant differences in the expression levels of procollagen α1 (III) mRNA between the Smad7 plasmid group and the normal control group or the vehicle plasmid group (t = 1.25 and 1.27, respectively; both t < t_0.05 and both P > 0.05), the expression level of procollagen α1 (III) mRNA in the TGF-β1 plus Smad7 plasmid group was significantly lower than those in the TGF-β1 group and the TGF-β1 plus vehicle plasmid group (t = 103.8 and 45.7, respectively; both t > t_0.01 and both P < 0.01).

CONCLUSION: Overexpression of Smad7 inhibits the expression of procollagen α1 (III) stimulated by exogenous TGF-β1 in cultured hepatic stellate cells.

Chinese medicines as a resource for liver fibrosis treatment

Liver fibrosis is a condition of abnormal proliferation of connective tissue due to various types of chronic liver injury often caused by viral infection and chemicals. Effective therapies against liver fibrosis are still limited. In this review, we focus on research on Chinese medicines against liver fibrosis in three categories, namely pure compounds, composite formulae and combination treatment using single compounds with composite formulae or conventional medicines. Action mechanisms of the anti-fibrosis Chinese medicines, clinical application, herbal adverse events and quality control are also reviewed. Evidence indicates that some Chinese medicines are clinically effective on liver fibrosis. Strict quality control such as research to identify and monitor the manufacturing of Chinese medicines enables reliable pharmacological, clinical and in-depth mechanism studies. Further experiments and clinical trials should be carried out on the platforms that conform to international standards.

Antiproliferative activity of triterpenoids from Eclipta prostrata on hepatic stellate cells

Hepatic stellate cells (HSCs) have been known to play a key role in the pathogenesis of liver fibrosis. In the course of screening antifibrotic activity of natural products employing HSC-T6, a rat hepatic stellate cell line as an in vitro assay system, the methanolic extract of aerial parts of Eclipta prostrata L. showed significant inhibitory activity on HSCs proliferation. Activity-guided fractionation led to the isolation of five oleanane-type triterpenoids, echinocystic acid (1), eclalbasaponin II (2), eclalbasaponin V (3), eclalbasaponin I (4) and eclalbasaponin III (5), which are all echinocystic acid derivatives. Among the five echinocystic acid derivatives isolated, echinocystic acid (1) and eclalbasaponin II (2) significantly inhibited the proliferation of HSCs in dose- and time-dependent manners. Our present study also suggests the importance of free carboxylic acid at C-28 position in echinocystic acid derivatives for the antifibrotic activity. Taken together, antifibrotic activity of E. prostrata and its triterpenoids might suggest the therapeutic potentials against liver fibrosis.

Preparation and characterization of solid lipid nanoparticles loaded traditional chinese medicine

Ultrasonication was employed to prepare solid lipid nanoparticles (SLN). The model traditional Chinese medicine, tetrandrine (TET), was incorporated into SLN. The TET-loaded SLN (TET-SLN) were spherical in the photograph of transmission electron microscope (TEM). The particle size measured by laser diffraction (LD) was found to be 157.3+/-8.2nm. Zeta potential analyzer suggested the zeta potential of TET-SLN was -29.36+/-3.68mV in distilled water. The entrapment efficiency (EE%) was determined with the sephadex gel chromatogram and high-performance liquid chromatogram (HPLC), and up to 90.59% of TET was incorporated. Stability evaluation showed relatively long-term stability with only slight particle growth (P>0.05) after storage at room temperature for 4 weeks. Therefore, ultrasonication is demonstrated to be a simple, available and effective method to prepare high quality SLN loaded traditional Chinese medicine.