Effect of a propolis extract and caffeic acid phenethyl ester on formation of aberrant crypt foci and tumors in the rat colon

Inhibitory effect of caffeic acid phenethyl ester on the growth of SW480 colorectal tumor cells involves β-catenin associated signaling pathway down-regulation

AIM: To study the anti-tumor effect of caffeic acid phenethyl ester (CAPE) and the influence of CAPE on β-catenin associated signaling pathway in SW480 colorectal cancer (CRC) cells.

METHODS: SW480 cells were treated with CAPE at serial concentrations. The proliferative status of cells was measured by methabenzthiazuron (MTT) assay. Cell cycle and cell apoptosis were analyzed using flow cytometry (FCM). Western blotting assay was used to evaluate the protein level of β-catenin, c-myc and cyclinD1. β-catenin localization was determined by indirect immunofluorescence.

RESULTS: CAPE displayed a strong inhibitory effect in a significant dose- and time-dependent manner on SW480 cell growth. FCM analysis showed that the ratio of G0 /G1 phase cells increased, S phase ratio decreased and apoptosis rate increased after SW480 cells were exposed to CAPE for 24 h. Pretreatment of SW480 cells with CAPE significantly suppressed β-catenin, c-myc and cyclinD1 protein expression. CAPE treatment was associated with decreased accumulation of β-catenin protein in nucleus and cytoplasm, and concurrently increased its accumulation on the surface of cell membrane.

CONCLUSION: CAPE can inhibit SW480 cell proliferation by inducing cell cycle arrest and apoptosis. Decreased β-catenin and the associated signaling pathway target gene expression may mediate the anti-tumor effects of CAPE.

A review of the effects and mechanisms of polyphenolics in cancer

This paper is a comprehensive review of the effects of bioactive polyphenolic compounds commonly found in many fruits and vegetables on cancer. These include the pheniolic acids, anthocyanins, catechins, stilbenes and several other flavonoids. We have attempted to compile information from most of the major studies in this area into one source. The review encompasses the occurrence and bioavailability of the polyphenolics, the in vitro and in vivo evidence for their effects on cancer, both positive and negative, and the various mechanisms by which the chemicals may exert their effects. Although most of the work done to date indicates a chemopreventative activity of these compounds, there are some studies that show cancer-inducing or no effects. There are several common mechanisms by which these chemicals exert their effects that could be conducive to additive, synergistic, or antagonistic interactions. These include effects on cellular differentiation, proliferation, and apoptosis, effects on proteins and enzymes that are involved in these processes at a molecular level, and other various effects through altered immune function and chemical metabolism.

Assessment of the Anti-Genotoxic, Anti-Proliferative, and Anti-Metastatic Potential of Crude Watercress Extract in Human Colon Cancer Cells

Although it is known to be a rich source of the putative anti-cancer chemicals isothiocyanates, watercress has not been extensively studied for its cancer preventing properties. The aim of this study was to investigate the potential chemoprotective effects of crude watercress extract toward three important stages in the carcinogenic process, namely initiation, proliferation, and metastasis (invasion) using established in vitro models. HT29 cells were used to investigate the protective effects of the extract on DNA damage and the cell cycle. The extract was not genotoxic but inhibited DNA damage induced by two of the three genotoxins used, namely hydrogen peroxide and fecal water, indicating the potential to inhibit initiation. It also caused an accumulation of cells in the S phase of the cell cycle indicating (possible) cell cycle delay at this stage. The extract was shown to significantly inhibit invasion of HT115 cells through matrigel. Component analysis was also carried out in an attempt to determine the major phytochemicals present in both watercress leaves and the crude extract. In conclusion, the watercress extract proved to be significantly protective against the three stages of the carcinogenesis process investigated.

Caffeic acid phenethyl ester (CAPE) attenuates cerebral vasospasm after experimental subarachnoidal haemorrhage by increasing brain nitric oxide levels

BACKGROUND

Cerebral vasospasm, a medical complication of aneurysmal subarachnoid hemorrhage (SAH), is associated with high morbidity and mortality rates, even after the aneurysm has been secured surgically or endovascularly. Evidence accumulated during the last decade suggest that scavenging a vasodilator, nitric oxide (NO), by superoxide anions (O(2)(-)), and activating a strong vasoconstructor, protein kinase C (PKC), are the two most important mechanisms in the pathogenesis of vasospasm. Our aim in this study was to determine whether caffeic acid phenethyl ester (CAPE), a non-toxic oxygen free radical scavenger, prevents vasospasm in an experimental rat model of SAH.

METHODS

Twenty eight rats (225-250 g) were divided into four groups equally: group 1, control group; group 2, SAH group; group 3, SAH plus placebo group; and group 4, SAH plus CAPE group. We used double haemorrhage method for SAH groups. Starting 6h after SAH, 10 micromol/kg CAPE or an equal volume of 0.9% saline were administered by intraperitoneal injection twice daily for 5 days to SAH plus CAPE and SAH plus placebo groups, respectively. CAPE or 0.9% saline injections were continued up to 5th day after SAH. Rats were sacrificed on the 5th day. Brain sections at the level of the pons were examined by light microscopy. Measurements were made for the cross-sectional areas of the lumen and the vessel wall (intimae plus media) of basilar artery by a micrometer. The levels of malondialdehyde (MDA), reduced glutathione (GSH), and nitric oxide (NO) were measured in rat brain tissue.

RESULTS

Administration of CAPE significantly attenuated the vasoconstriction of the basilar artery. There were marked narrowing in the lumens of and thickening in the walls of basilar arteries in the SAH, and the SAH plus placebo compared with CAPE group (p < 0.001). We also observed that CAPE administration significantly decreased the tissue level of MDA, while significantly increased the tissue levels of GSH, NO in the SAH plus CAPE group compared to only SAH group, p < 0.05.

CONCLUSIONS

Our results indicate that CAPE is effective in attenuating delayed cerebral vasoconstriction following experimental SAH. Our findings also suggest that the elevation of lipid peroxidation and reduction of NO bioavailability, resulting from the generation and the interaction of free radicals, have a significant role in the pathogenesis of vasospasm after SAH.

Evaluation of Manisa propolis effect on leukemia cell line by telomerase activity

Propolis is a resinous substance which is used by bees to repair and maintain their hives. It has more than 180 compounds including flavonoids, phenolic acids and its esters which have anti-inflammatory, antibacterial, antiviral, immunomodulatory, antioxidant and antiproliferative effects. Propolis is shown to inhibit cell division and protein synthesis. However the exact mechanism underlying antitumor effect is not clearly described. On the other hand progressive telomere shortening to a critical level results with senescence of normal cells by inducing apoptosis and telomerase prevents erosion of telomeres. In this study we aimed to evaluate hTERT ratios in propolis-treated T-cell acute lymphoblastic leukemia (CCFR-CEM) cell line. Cell counts and cell viability of propolis-treated and propolis-free T-cell acute lymphoblastic leukemia (CCFR-CEM) cell line were assessed by trypan blue dye exclusion test and MTT assay. The LightCycler instrument was used (online real-time PCR) for the quantification of hTERT in CCFR-CEM cell line. The hTERT ratio significantly decreased 60 and 93% after 24 and 72 h respectively compared to the initial value of the cells incubated with propolis. It had almost no cytotoxic effect and caused 30, 30, 22 and 12% decrease in cell counts after 24, 48, 72 and 96 h respectively which is statistically significant. In conclusion propolis may show antitumor and apoptotic effect via inhibiting telomerase expression besides the mechanisms which have been described previously.

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.

Effect of caffeic acid phenethyl ester on proliferation and apoptosis of colorectal cancer cells in vitro

AIM: To study the effect of caffeic acid phenethyl ester (CAPE) on proliferation, cell cycle, apoptosis and expression of β-catenin in cultured human colorectal cancer (CRC) cell line HCT116.

METHODS: HCT116 cells were treated with CAPE at serial concentrations of 80, 40, 20, 10, 5, 2.5 mg/L. The proliferative status of HCT116 cells was measured by using methaben-zthiazuron (MTT) assay. Cell cycle was analyzed by using flow cytometry (FCM) with propidium iodide (PI) labeling method. The rate of apoptosis was detected by using FCM with annexin V-FITC and PI double labeling method. β-catenin levels were determined by Western blotting. β-catenin localization in HCT116 was determined by indirect immunofluorescence.

RESULTS: After HCT116 cells were exposed to CAPE (80, 40, 20, 10, 5, and 2.5 mg/L) for 24, 48, 72, 96 h, CAPE displayed a strong growth inhibitory effect in a dose- and time-dependent manner against HCT116 cells. FCM analysis showed that the ratio of G₀/G₁ phase cells increased, S phase ratio decreased and apoptosis rate increased after HCT116 cells were exposed to CAPE (10, 5, and 2.5 mg/L) for 24 h. CAPE treatment was associated with decreased cytoplasmic β-catenin, nuclear β-catenin and a concurrent increase in β-catenin protein expression at cell-cell junctions.

CONCLUSION: CAPE could inhibit HCT116 cell proliferation and induce cell cycle arrest and apoptosis. Decreased β-catenin protein expression may mediate the anti-proliferative effects of CAPE.

Inhibition of cyclooxygenase-2 expression and restoration of gap junction intercellular communication in H-ras-transformed rat liver epithelial cells by caffeic acid phenethyl ester

One of the most frequent defects in human cancers is the uncontrolled activation of the ras signaling pathways. Increased expression of cyclooxygenase-2 (COX-2) and inhibition of gap junction intercellular communication (GJIC) have been frequently observed in several forms of human malignancies. The present study investigated the effects of caffeic acid phenethyl ester (CAPE), a chemopreventive phytochemical derived from honey propolis, on COX-2 expression and GJIC in Harvey-ras-transformed WB-F344 rat liver epithelial cells (H-ras WB cells). H-ras induced COX-2 expression in WB-F344 rat liver epithelial cells (WB cells). H-ras WB cells also exhibited complete inhibition of GJIC and predominant unphosphorylation of connexin 43 (Cx43), a major protein modulating GJIC. CAPE significantly inhibited the constitutive expression of COX-2 and restored the disrupted GJIC through the phosphorylation of Cx43 at a concentration of 12.5 microM in H-ras WB cells. Although the molecular basis for the cancer chemopreventive activity of CAPE is not completely understood, several studies suggest that CAPE is a potent and specific inhibitor of the transcription factor nuclear factor kappaB (NF-kappaB) activation. We also found that CAPE significantly inhibited H-ras-induced NF-kappaB DNA-binding activity without affecting the activation of extracellular signal-regulated kinase and p38 mitogen-activated protein kinase, which are major intracellular molecules involved in the Ras signaling pathways. In conclusion, CAPE may exert cancer chemopreventive effects through the inhibition of COX-2 expression and the restoration of disrupted GJIC induced by H-ras, possibly by targeting NF-kappaB.

Chilean propolis: antioxidant activity and antiproliferative action in human tumor cell lines

Propolis, a natural product derived from plant resins collected by honeybees, has been used for thousands of years in traditional medicine all over the world. The composition of the propolis depends upon the vegetation of the area from where it was collected and on the bee species. In this study, we investigated the antioxidant activity of a propolis sample, provided by NATURANDES-CHILE, collected in a temperate region of central Chile. In addition, this natural compound was tested for its antiproliferative capacity on KB (human mouth epidermoid carcinoma cells), Caco-2 (colon adenocarcinoma cells) and DU-145 (androgen-insensitive prostate cancer cells) human tumor cell lines. Results showed that this Chilean propolis sample exhibits interesting biological properties, correlated with its chemical composition and expressed by its capacity to scavenge free radicals and to inhibit tumor cell growth.

Cytotoxicity of phenolic acid phenethyl esters on oral cancer cells

Many phenolic acid phenethyl esters possess diverse biological effects including anti-cancer activity. A series of 14 derivatives were synthesized for the evaluation of their cytotoxic effect on oral cancer cells. These derivatives were tested by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric and trypan blue dye exclusion assay on the growth of oral squamous cell carcinoma (SAS), oral epidermoid carcinoma-Meng 1 (OEC-M1), and normal human oral fibroblast (NHOF) cells, respectively. Caffeic acid phenethyl esters, 3a (CAPE), and 3b, 3c, and 3d showed cytotoxic effects on the SAS and OEC-M1 cell lines, but not the NHOF cell line at a 5-100 microM dose range. Flow cytometric analysis showed that 3c caused OEC-M1 cell arrest at G2/M phase. Such differential effects on representative cancer and normal cells suggested these compounds might be useful in oral cancer chemotherapy.

Oral flavonoid supplementation attenuates atherosclerosis development in apolipoprotein E-deficient mice

OBJECTIVE

Caffeic acid phenethyl ester (CAPE), a natural flavonoid, specifically blocks activation of nuclear factor-kappaB (NF-kappaB). We examined the effects of oral CAPE supplementation on atherogenesis in apolipoprotein E-deficient (apoE-/-) mice.

METHODS AND RESULTS

Ten-week-old male apoE-/- mice were supplemented orally with CAPE (30 mg/kg body weight) for 12 weeks. At the end of administration, atherosclerosis progression, NF-kappaB activity, gene expression profiling by microarray analysis, and oxidative stress were studied. Treatment of apoE-/- mice with CAPE significantly reduced aortic atherosclerosis, NF-kappaB activity, and expression of NF-kappaB-related genes in the aorta. Moreover, expression of other gene clusters such as basic transcription factors, growth factors, cytokines, cell adhesion proteins, and extracellular matrix were also significantly reduced by treatment with CAPE. Plasma isoprostane level in apoE-/- mice was also significantly reduced by CAPE.

CONCLUSIONS

In apoE-/- mice, oral CAPE supplementation attenuates the atherosclerotic process. This may be attributable to direct inhibition of NF-kappaB in the lesion and reduction of systemic oxidative stress. In apoE-/- mice, oral caffeic acid phenethyl ester (CAPE) supplementation attenuates the atherosclerotic process and reduces NF-kappaB activity and expression of NF-kappaB-related genes in the aorta. This may be attributable to direct inhibition of NF-kappaB in the lesion and reduction of systemic oxidative stress.

Aberrant crypt foci and beta-catenin accumulated crypts; significance and roles for colorectal carcinogenesis

Preneoplastic or precancerous lesions in the large bowel have been characterized in terms of morphology and histochemical phenotype. However, the detailed histogenesis and relation of particular lesions to malignancies has not yet to be unequivocally clarified. Aberrant crypt foci (ACF), identified in whole-mount preparations of colonic mucosa in rodents and also recognized in human colon, are now frequently used as effective surrogate biomarkers for experimentally detection of chemopreventive agents against colorectal cancers, but the preneoplastic or precancerous nature of ACF in rodents and humans still remains inconclusive. Relatively recently, early appearing beta-catenin accumulated crypts (BCAC) have been described in en face preparations of colonic mucosa in rodents which differ from ACF in many features. BCAC are suggested to be premalignant rather than preneoplastic. The pathological significance of both lesions, including their advantages and disadvantages as surrogate end points for large bowel neoplasms, and roles in colorectal carcinogenesis are discussed here.

Inhibitirve effect of caffeic acid phenethyl ester on proliferation of human colorectal cancer cell line HCT116

AIM: To study the effect of caffeic acid phenethyl ester (CAPE) on proliferation, cell cycle, apoptosis in the cultured colorectal cancer cell line HCT116.

METHODS: HCT116 cells were treated with CAPE at serial concentrations of 80, 40, 20, 10, 5, and 2.5 mg/L. The proliferative status of HCT116 cells was measured by using methabenzthiazuron (MTT) assay. Cell cycle was analyzed by using flow cytometry (FCM) with propidium iodide (PI) labeling method. The rate of apoptosis was detected by using FCM with Annexin V-FITC and PI double labeling method.

RESULTS: After HCT116 cells were exposed to CAPE (80, 40, 20, 10, 5 and 2.5 mg/L) for 24, 48, 72 and 96 h, CAPE displayed a strong growth inhibitory effect on HCT116 cells in a dose-and time-dependent manner. FCM analysis showed that G0 /G1 phase rate increased, S phase rate decreased and apoptosis rate increased after HCT116 cells were exposed to CAPE (10, 5, and 2.5 mg/L) for 24 h, which were positively related to the concentration of CAPE.

CONCLUSION: CAPE can inhibit the proliferation of human colorectal cancer cell line HCT116, which is related to the cell cycle arrest and apoptosis.

Effect of propolis on human cartilage and chondrocytes

Propolis, a natural product derived from plant resins collected by the honeybees, has been used for thousands of years in folk medicine for several purposes. The extract that contains amino acids, phenolic acids, phenolic acid esters, flavonoids, cinnamic acid, terpenes and caffeic acid, possesses several biological activities such as anti-inflammatory, immunostimulatory, anti-viral and anti-bacterial. In this study, we assay the effects of propolis extract on the production of key molecules released during chronic inflammatory events as nitric oxide (NO) and glycosaminoglycans (GAGs) in cultures of human cartilaginous tissues and chondrocytes, stimulated with interleukin-1beta (IL-1beta). We observed that this natural compound and its active principle, caffeic acid phenethyl ester (CAPE), were able to contrast the harmful effects of IL-1beta. Our data clearly demonstrated the protective action of propolis in cartilage alteration, that appears greater than that elicited by indomethacin, commonly employed in joint diseases.

[A rare cause of neonatal exudative enteropathy: congenital Langerhans cell histiocytosis (histiocytosis X)]

A case of Langerhans cell histiocytosis is reported in a neonate. Intestinal involvement was especially diffuse and severe, presenting as a protein-losing enteropathy secondary to massive mucosal infiltration by histiocytic cells. The infant died at the age of 3 1/2 months despite therapy with corticosteroids and vinblastine then etoposide and interferon. Such an outcome confirmed the severity of forms with neonatal onset and digestive involvement.