Effect of caffeic acid phenethyl ester on proliferation and apoptosis of hepatic stellate cells in vitro

Gellan-Based Hydrogel as a Drug Delivery System for Caffeic Acid Phenethyl Ester in the Treatment of Oral Candida albicans Infections

Candida albicans can cause various types of oral infections, mainly associated with denture stomatitis. Conventional therapy has been linked to high recurrence, toxicity, and fungal resistance, necessitating the search for new drugs and delivery systems. In this study, caffeic acid phenethyl ester (CAPE) and gellan gum (GG) were studied as an antifungal agent and carrier system, respectively. First, we observed that different GG formulations (0.6 to 1.0% wt/vol) were able to incorporate and release CAPE, reaching a controlled and prolonged release over 180 min at 1.0% of GG. CAPE-GG formulations exhibited antifungal activity at CAPE concentrations ranging from 128 to >512 µg/mL. Furthermore, CAPE-GG formulations significantly decreased the fungal viability of C. albicans biofilms at short times (12 h), mainly at 1.0% of GG (p < 0.001). C. albicans protease activity was also reduced after 12 h of treatment with CAPE-GG formulations (p < 0.001). Importantly, CAPE was not cytotoxic to human keratinocytes, and CAPE-GG formulations at 1.0% decreased the fungal burden (p = 0.0087) and suppressed inflammation in a rat model of denture stomatitis. Altogether, these results indicate that GG is a promising delivery system for CAPE, showing effective activity against C. albicans and potential to be used in the treatment of denture stomatitis.

Cloning of STC-1 and analysis of its differential expression in Hezuo pig

The purpose of this study was to examine STC-1's structure, function, and differential expression in large and miniature pigs. We cloned the Hezuo pig's coding sequence, compared its homology, and used bioinformatics to assess the structure. RT-qPCR and Western blot were used to detect the expression in ten tissues of Hezuo pig and Landrace pig. The results showed that Hezuo pig was most closely related to Capra hircus and most distantly related to Danio rerio. The protein STC-1 has a signal peptide and its secondary structure is dominated by the alpha helix. The mRNA expression in the spleen, duodenum, jejunum, and stomach of Hezuo pigs was higher than that of Landrace pigs. And except for heart and duodenum, expression of the protein in Hezuo pig was higher than in another. In conclusion, STC-1 is highly conserved among different breeds of pigs, and the expression and distribution of its mRNA and protein are different in large and miniature pigs. This work can lay the foundation for future study into the mechanism of action of STC-1 in Hezuo pigs and the enhancement of breeding in miniature pigs.

Caffeic acid phenethyl ester up-regulates antioxidant levels in hepatic stellate cell line T6 via an Nrf2-mediated mitogen activated protein kinases pathway

AIM

To investigate the antioxidant effect of caffeic acid phenethyl ester (CAPE) in hepatic stellate cell-T6 (HSC-T6) cells cultured in vitro and the potential mechanisms.

METHODS

HSC-T6 cells were cultured in vitro and treated with various concentrations of CAPE for 24, 48 and 72 h, respectively. Cell proliferation was investigated using the MTT assay, and cell ultrastructural alterations were observed by transmission electron microscopy. Flow cytometry was employed to investigate the effects of CAPE on apoptosis and the levels of reactive oxygen species in HSC-T6 cells cultured in vitro. An enzyme immunoassay instrument was used to evaluate antioxidant enzyme expression. The effect on α-smooth muscle actin was shown using immunofluorescence. Gene and protein levels of Nrf2, related factors, and mitogen activated protein kinases (MAPKs), in HSC-T6 cells were detected using RT-PCR and Western blot, respectively.

RESULTS

CAPE inhibited the proliferation and activation of HSC-T6 cells cultured in vitro. CAPE increased the antioxidant levels and the translocation of Nrf2 from the cytoplasm to the nucleus in HSC-T6 cells. Moreover, the phosphorylation of MAPKs in cells decreased in response to CAPE. Interestingly, CAPE-induced oxidative stress in the cells was significantly attenuated by pretreatment with MAPKs inhibitors.

CONCLUSION

CAPE inhibits cell proliferation and up-regulates the antioxidant levels in HSC-T6 cells partly through the Nrf2-MAPKs signaling pathway.

The pro-fibrotic properties of transforming growth factor on human fibroblasts are counteracted by caffeic acid by inhibiting myofibroblast formation and collagen synthesis

Fibrosis is a chronic disorder affecting many organs. A universal process in fibrosis is the formation of myofibroblasts and the subsequent collagen deposition by these cells. Transforming growth factor beta1 (TGFβ1) plays a major role in the formation of myofibroblasts, e.g. by activating fibroblasts. Currently, no treatments are available to circumvent fibrosis. Caffeic acid phenethyl ester (CAPE) shows a broad spectrum of biological activities, including anti-fibrotic properties in vivo in mice and rats. However, little is known about the direct effects of CAPE on fibroblasts. We have tested whether CAPE is able to suppress myofibroblast formation and collagen formation of human dermal and lung fibroblasts exposed to TGFβ1, and found that this was indeed the case. In fact, the formation of myofibroblasts by TGFβ1 and subsequent collagen formation was completely abolished by CAPE. The same was observed for fibronectin and tenascin C. The lack of myofibroblast formation is likely due to the suppression of GLI1 and GLI2 expression by CAPE because of diminished nuclear SMAD2/3 levels. Post-treatment with CAPE after myofibroblast formation even resulted in a partial reversal of myofibroblasts into fibroblasts and/or reduction in collagen formation. Major discrepancies were seen between mRNA levels of collagen type I and cells stained positive for collagen, underlining the need for protein data in fibrosis studies to make reliable conclusions.

Selective inhibition of activated stellate cells and protection from carbon tetrachloride-induced liver injury in rats by a new PPARgamma agonist KR62776

Activated hepatic stellate cells (HSC) are the primary source of extracellular matrix proteins found in liver fibrosis/cirrhosis patients. Therefore, the prevention of HSC activation is an important strategy for treating severe liver injury. This study examined the effects of KR62776, a new peroxisome proliferator-activated receptor gamma (PPARgamma) agonist, on the rate of cell proliferation and expression of alpha-smooth muscle actin (alpha-SMA) in rat hepatic stellate HSC-T6 cells. In addition, its effects on the liver damage induced by carbon tetrachloride were investigated. KR62776 caused the apoptosis of activated HSC-T6 cells with the concomitant decrease in the alpha-smooth muscle actin levels in a time- and concentration-dependent manner. However, KR62776 did not cause the apoptosis of human HepG2 and rat McARH7777 hepatoma cells, suggesting that KR62776 has a specific effect on stellate cells. KR62776 increased the levels of Gadd45, p27, p21 and PPARgamma proteins but decreased the cell cyclerelated proteins, such as cdk2, cyclin B and cyclin D1. These changes were reversed by BADGE, a specific PPARgamma antagonist, indicating that the effects of KR62776 are, at least in part, PPARgamma-dependent. In addition, KR62776 administration showed some protection against carbon tetrachloride-induced hepatocellular damage in rats. Overall, these results suggest that KR62776 may have potential in the chemoprevention of liver fibrosis/cirrhosis.

Taurocholate feeding to bile duct ligated rats prevents caffeic acid-induced bile duct damage by changes in cholangiocyte VEGF expression

Cholangiocytes are the target cells in cholestatic models of ductal hyperplasia including bile duct ligation (BDL). We have shown that: (i) cholangiocytes express VEGFR-2 and VEGFR-3; (ii) VEGF-A and VEGF-C stimulate cholangiocyte proliferation via an autocrine mechanism; and (iii) chronic administration of VEGF-A prevents cholangiocyte damage induced by hepatic artery ligation. Caffeic acid phenethyl ester (CAPE) induces growth inhibition in different cells. Taurocholic acid (TC) protects cholangiocytes against injury induced by parasympathetic or sympathetic denervation. The aims of this study were to determine if: (i) CAPE induces bile duct damage; and (ii) TC prevents CAPE-induced bile duct damage by increasing cholangiocyte VEGF expression.

METHODS

Normal and BDL rats (immediately after surgery) were fed 1% TC or control diet in the absence/presence of daily IP injections of CAPE (10 mg/Kg BW). One week later, we evaluated: (i) cholangiocyte apoptosis, proliferation and ductal mass in liver sections; (ii) functional activity by measuring secretin-stimulated bile and bicarbonate secretion; and (iii) VEGF-A/C and VEGFR-2/R-3 expression in liver sections. In vitro, BDL cholangiocytes were exposed to CAPE (40 microM) in the absence/presence of TC (40 microM) with and without pretreatment with VEGF receptor inhibitors before evaluating cholangiocyte apoptosis and proliferation.

RESULTS

Chronic CAPE administration to BDL rats increased cholangiocyte apoptosis and decreased ductal mass. This effect was associated with reduced expression of VEGF-A, VEGF-C, VEGFR-2 and VEGFR-3. In vivo, TC feeding partly prevented CAPE-induced changes in cholangiocyte apoptosis and growth and loss of ductal secretion. The protective effect of TC was associated with enhanced VEGF-A, VEGF-C, VEGFR-2 and VEGFR-3. In vitro, TC partially prevented CAPE-induced increases in apoptosis and decreases in cholangiocyte proliferation. These changes were reversed by pretreatment with VEGF-receptor inhibitors.

CONCLUSION

Manipulation of cholangiocyte VEGF expression by bile acids may be important in preventing the impairment of cholangiocyte proliferation by exogenous agents.

A single dose of caffeic acid phenethyl ester prevents initiation in a medium-term rat hepatocarcinogenesis model

AIM: To study of the effect of caffeic acid phenethyl ester (CAPE) on the initiation period in a medium-term assay of hepatocarcinogenesis.

METHODS: Male Wistar rats were subjected to a carcinogenic treatment (CT) and sacrificed at 25^th d; altered hepatic foci (AHF) were generated efficiently. To a second group of rats a single 20 mg/kg doses of CAPE was given 12 h before initiation with CT and were sacrificed at 25^th d. We evaluated the expression of preneoplastic markers as γ-glutamyltranspeptidase (GGT) and glutathione S-transferase type pi protein (GSTp) by histochemistry, RT-PCR and Western blot analyses, respectively. We measured thiobarbituric acid reactive substances (TBARS) in homogenates of liver and used Unscheduled DNA Synthesis (UDS) assay by incorporation of [³H] thymidine (³HdT) in primary hepatocyte cultures (PHC).

RESULTS: At 25^th d after CT CAPE reduced the observed increase of GGT⁺AHF by 84% and liver expression of ggt mRNA by 100%. In case of the GSTp protein, the level was reduced by 90%. As indicative of oxidative stress generated by diethylnitrosamine (DEN) 12 h after its administration, we detected a 68% increase of TBARS. When CAPE was administered before DEN, it completely protected from liver TBARS induction. To have an indication of the sole effect of CAPE on initiation, two carcinogens were tested in a UDS assay in PHC, we used methyl-n-nitrosoguanidine as a direct carcinogen and DEN, as indirect carcinogen. In this assay, genotoxic damage caused by carcinogens was abolished at 5μM CAPE concentration.

CONCLUSION: Our results demonstrated that CAPE possesses anti-genotoxic and antineoplastic capabilities, by an anti-oxidative and free-radical scavenging mechanism.

The role and regulation of hepatic stellate cell apoptosis in reversal of liver fibrosis

Liver fibrosis and its end-stage disease cirrhosis are major world health problems arising from chronic injury of the liver by a variety of etiological factors including viruses, alcohol and drug abuse, the metabolic syndrome, autoimmune disease and hereditary disorders of metabolism. Fibrosis is a progressive pathological process in which wound-healing myofibroblasts of the liver respond to injury by promoting replacement of the normal hepatic tissue with a scar-like matrix composed of cross-linked collagen. Until recently it was believed that this process was irreversible. However emerging experimental and clinical evidence is starting to show that even cirrhosis is potentially reversible. Key to this is the discovery that reversion of fibrosis is accompanied by clearance of hepatic stellate cells (HSC) by apoptosis. Furthermore, proof-of-concept studies in rodents have demonstrated that experimental augmentation of HSC apoptosis will promote the resolution of fibrosis. Consequently there is now considerable interest in determining the molecular events that regulate HSC apoptosis and the discovery of drugs that will stimulate HSC apoptosis in a selective manner. This review will consider the regulatory role played by growth factors (e.g. NGF, IGF-1, TGFbeta), death receptor ligands (TRAIL, FAS), components and regulators of extracellular matrix (integrins, collagen, matrix metalloproteinases and their tissue inhibitors) and signal transduction proteins and transcription factors (Rho/Rho kinase, Jun N-terminal Kinase (JNK), IkappaKinase (IKK), NF-kappa B). The potential for known pharmacological agents such as gliotoxin, sulfasalazine, benzodiazepine ligands, curcumin and tanshinone I to induce HSC apoptosis and therefore to be used therapeutically will be explored.

Antiproliferation and radiosensitization of caffeic acid phenethyl ester on human medulloblastoma cells

PURPOSE

To investigate antiproliferative and radiosensitizing effects of caffeic acid phenethyl ester (CAPE) on medulloblastoma (MB) Daoy cells.

METHODS AND MATERIALS

Daoy cells were treated with CAPE in different concentrations and assessed for cell viability, apoptosis, cell cycles, cyclin B1 expressions, radiosensitization and chemosensitization. Human astroglia SVGp12 cells were treated with CAPE to present the possible protection or complication effects in normal tissues.

RESULTS

CAPE inhibited the growth of Daoy cells in a time- and concentration-dependent manner in MTT and Trypan blue exclusion assays. Flow cytometry revealed that CAPE significantly decreased G2/M fraction, and increased the S phase fraction. Western blot demonstrated a down-regulated cyclin B1 protein expression. Pretreatment with CAPE markedly decreased the viability of irradiated Daoy cells. The sensitizer enhancement ratios (SERs) were increased in CAPE-treated Daoy cells. CAPE in doxorubicin and cisplatin did not show chemosensitizing effect.

CONCLUSIONS

These findings demonstrate the antiproliferative and radiosensitizing effects of CAPE for Daoy cells, which might bring improvement to the treatment of MB. For clinical application, in vivo models are expected.

Caffeic acid phenethyl ester (CAPE) prevents transformation of human cells by arsenite (As) and suppresses growth of As-transformed cells

Recent evidence suggests that inflammatory cytokines and growth factors contribute to arsenite (As)-induced human carcinogenesis. We investigated the expression of inflammatory cytokine mRNAs during the transformation process induced by chronic As exposure in non-tumorigenic human osteogenic sarcoma (N-HOS) cells using gene arrays, and results were confirmed by RT-PCR and protein arrays. Caffeic acid phenethyl ester (CAPE), a naturally occurring immunomodulating agent, was used to evaluate the role of inflammatory factors in the process of As-mediated N-HOS cell transformation and in As-transformed HOS (AsT-HOS) cells. We found that an 8-week continuous exposure of N-HOS to 0.3 microM arsenite resulted in HOS cell transformation. That exposure also caused substantial decreases in inflammatory cytokine mRNAs, such as interleukin (IL) IL-1alpha, IL-2, IL-8, IL-18, MCP-1, TGF-beta2, and TNF-alpha, while it increased c-jun mRNA in a time-dependent manner. Co-incubation of N-HOS with As and CAPE (0.5-2.5 microM) prevented As-mediated declines in cytokine mRNAs in the co-treated cells, as well as their transformation to anchorage independence, while it caused decreases in c-jun mRNA. CAPE (up to 10 microM) had no effect on growth of N-HOS cells. However, CAPE (1-10 microM) treatment of AsT-HOS cells inhibited cell growth, induced cell cycle G2/M arrest, and triggered apoptosis, accompanied by changes in cytokine gene expression, as well as decreases in cyclin B1 and cdc2 abundance. Resveratrol (RV) and (-)(.) epigallocatechin gallate (EGCG), preventive agents present in grapes and green tea, respectively, induced similar changes in AsT-HOS cell growth but required much higher doses than CAPE to cause 50% growth arrest (<2.5 microM CAPE versus 25 microM RV or 50 microM EGCG). Overall, our findings suggest that inflammatory cytokines play an important role in the suppressive effects of CAPE on As-induced cell transformation and in the selective cytotoxicity of CAPE to As-transformed HOS cells.

Use of caffeic acid phenethyl ester and cortisone may prevent proliferative vitreoretinopathy

PURPOSE: To investigate whether caffeic acid phenethyl ester (CAPE) and cortisone prevent proliferative vitreoretinopathy (PVR). METHODS: Twenty pigmented rabbits were used in this study. All rabbits except controls received an intravitreal injection of 0.15 ml (75,000 U) of platelet-rich plasma into their left eye. The animals were divided into four groups: group I was treated with intraperitoneal injection of 0.5 ml (15 micromol/kg) of CAPE for 3 days, group II received 0.15 ml (4 mg/kg) of intravitreal cortisone, group III received nothing (blank group), and group IV (control group) received only 1 ml of 1% ethanol intraperitoneally daily for 3 days. Proliferative changes were graded in a masked fashion by indirect ophthalmoscopy for a 15-day follow-up period. The malondialdehyde (MDA), reduced glutathione (GSH) and total nitrite (NO) levels were measured in the vitreous humor. RESULTS: The grades of PVR were B-C in group I, and C-D in group II. The PVR grade in the control group was C-D. The mean MDA level in group I (4.0+/-0.8 micromol/l) was significantly lower than in the blank group (6.0 micromol/l) (p < 0.05). The mean GSH level in group I (71.0+/-11.2 micromol/l) was significantly different than in the blank group (p < 0.05). The MDA and GSH levels in group II were 4.7+/-0.6 micromol/l and 53.8+/-7.8 micromol/l, respectively. Both these levels were not significantly different from the blank group (p > 0.05). The NO levels in both treatment groups were significantly lower than in the blank group (p < 0.001). CONCLUSION: These findings suggest an inhibitory effect of CAPE on PVR. The inhibitory effect was supported by lower MDA and NO with higher GSH levels in treatment groups than in the blank group. There was no detected significant effect of cortisone for preventing PVR experimentally.

Caffeic acid phenethyl ester protects kidneys against carbon tetrachloride toxicity in rats

Caffeic acid phenethyl ester (CAPE), an active component of propolis produced by honeybees, exhibits antioxidant and anti-inflammatory properties. The aim of this study was to investigate possible protective effects of CAPE on carbon tetrachloride (CCl4)-induced renal damage in rats. A total of 24 animals were divided into three equal groups: the control rats received pure olive oil subcutaneously, rats in the second group were injected with CCl4 (0.5 ml/kg, s.c. in olive oil) and rats in the third group were injected with CCl4 (0.5 ml/kg) plus CAPE (10 micromol/kg, i.p.) every other day for one month. At the end of the experimental period, the animals were sacrificed and blood samples were collected. Serum urea and creatinine levels and renal malondialdehyde (MDA) contents were determined. Histopathological examination of the kidney was also performed using light microscopic methods. It was found that kidney MDA levels were increased significantly following CCl4 exposure and this increase was significantly inhibited by CAPE treatment, while no significant changes were observed in serum urea and creatinine levels. CCl4 administration alone also caused histopathologically prominent damage in the kidney compared to the control group. Glomerular and tubular degeneration, interstitial mononuclear cell infiltration and fibrosis, and vascular congestion in the peritubular blood vessels were observed in the renal cortex. With exception of rare vascular congestions, these histopathological changes were disappeared in rats treated with CCl4 plus CAPE. In view of the present findings, it is suggested that CAPE protects kidneys against CCl4 toxicity.