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ABSTRACT: Epigenetic modifications are important in tumorigenesis. The most frequent epigenetic phenomena in cancer are histone deacetylation and DNA hypermethylation, which lead to gene silencing, particularly of tumor suppressor genes. However, monotherapies with histone deacetylase (HDAC) or DNA methyltransferase (DNMT) inhibitors lack efficacy, hence there is a need to enhance their anticancer action in a safe and effective combination therapy. The present study investigated the epigenetic effects of the natural flavonolignan silibinin in a model of colon cancer progression, the primary adenocarcinoma cells SW480 and their derived metastatic cells SW620. Silibinin did not change the activity of HDACs, but it was able to significantly inhibit DNMT activity in both SW480 and SW620 cells. The clinically used HDAC inhibitor, suberoylanilide hydroxamic acid (SAHA), and the broad spectrum HDAC inhibitor, trichostatin A (TSA), combined with silibinin demonstrated synergistic effects on cell death induction, may be related to its DNMT inhibition properties. The present data suggest that treatments combining silibinin and HDAC inhibitors may represent a promising approach, given the non-toxic nature of silibinin and the fact that HDAC inhibitors selectively target cancer cells.
Oncology letters 04/2013; 5(4):1273-1277. · 0.11 Impact Factor
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ABSTRACT: The present study investigated the molecular mechanism of silibinin-induced antitumoral effects in hepatocarcinoma Hep-55.1C cells in vitro and in a hepatocarcinoma model in mice.
Cell death was analyzed by flow cytometry. The genetic expression of apoptotic and inflammatory biomarkers was assessed by quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR). Orthotopic grafting of Hep-55.1C cells into the liver of C57BL/6J mice was performed, and tumor growth was followed by micro-computed imaging.
Silibinin activated the extrinsic apoptotic pathway in Hep55.1C cells, as attested by the up-regulation of TNF-related apoptosis-inducing ligand (TRAIL) and TRAIL Death receptor 5 (DR5) transcripts, and by the activation of caspase-3 and -8. After grafting of Hep-55.1C cells into mouse liver, the oral administration of silibinin at 700 mg/kg body weight for four weeks caused a significant reduction of tumor growth, associated with the down-regulation of inflammatory components [matrix metalloproteinase -7 and -9, (MMP-7, MMP-9), Interleukin-1 beta (IL1β)], the up-regulation of apoptotic mediators (TRAIL, DR5), and caspase-3 activation.
Silibinin treatment exerted important anticarcinogenic effects, including the activation of TRAIL death receptor apoptotic signaling pathway in Hep-55.1C hepatocarcinoma cells, both in vitro and in hepatocarcinoma grafts in mice.
Anticancer research 07/2012; 32(7):2455-62. · 1.73 Impact Factor
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ABSTRACT: Silibinin, a flavonolignan, is the major active component of the milk thistle plant (Silybum marianum) and has been shown to possess anti-neoplastic properties. TNF-related apoptosis-inducing ligand (TRAIL) is a promising anti-cancer agent which selectively induces apoptosis in cancer cells. However, resistance to TRAIL-induced apoptosis is an important and frequent problem in cancer treatment. In this study, we investigated the effect of silibinin and TRAIL in an in vitro model of human colon cancer progression, consisting of primary colon tumor cells (SW480) and their derived TRAIL-resistant metastatic cells (SW620). We showed by flow cytometry that silibinin and TRAIL synergistically induced cell death in the two cell lines. Up-regulation of death receptor 4 (DR4) and DR5 by silibinin was shown by RT-PCR and by flow cytometry. Human recombinant DR5/Fc chimera protein that has a dominant-negative effect by competing with the endogenous receptors abrogated cell death induced by silibinin and TRAIL, demonstrating the activation of the death receptor pathway. Synergistic activation of caspase-3, -8, and -9 by silibinin and TRAIL was shown by colorimetric assays. When caspase inhibitors were used, cell death was blocked. Furthermore, silibinin and TRAIL potentiated activation of the mitochondrial apoptotic pathway and down-regulated the anti-apoptotic proteins Mcl-1 and XIAP. The involvement of XIAP in sensitization of the two cell lines to TRAIL was demonstrated using the XIAP inhibitor embelin. These findings demonstrate the synergistic action of silibinin and TRAIL, suggesting chemopreventive and therapeutic potential which should be further explored.
Apoptosis 05/2012; 17(8):797-809. · 4.07 Impact Factor
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ABSTRACT: Silibinin, a flavonolignan isolated from the milk thistle plant (Silybum marianum), possesses anti-neoplastic properties. In vitro and in vivo studies have recently shown that silibinin inhibits the growth of colorectal cancer (CRC). The present study investigates the mechanisms of silibinin-induced cell death using an in vitro model of human colon cancer progression, consisting of primary tumor cells (SW480) and their derived metastatic cells (SW620) isolated from a metastasis of the same patient. Silibinin induced apoptotic cell death evidenced by DNA fragmentation and activation of caspase-3 in both cell lines. Silibinin enhanced the expression (protein and mRNA) of TNF-related apoptosis-inducing ligand (TRAIL) death receptors (DR4/DR5) at the cell surface in SW480 cells, and induced their expression in TRAIL-resistant SW620 cells normally not expressing DR4/DR5. Caspase-8 and -10 were activated demonstrating the involvement of the extrinsic apoptotic pathway in silibinin-treated SW480 and SW620 cells. The protein Bid was cleaved in SW480 cells indicating a cross-talk between extrinsic and intrinsic apoptotic pathway. We demonstrated that silibinin activated also the intrinsic apoptotic pathway in both cell lines, including the perturbation of the mitochondrial membrane potential, the release of cytochrome c into the cytosol and the activation of caspase-9. Simultaneously to apoptosis, silibinin triggered an autophagic response. The inhibition of autophagy with a specific inhibitor enhanced cell death, suggesting a cytoprotective function for autophagy in silibinin-treated cells. Taken together, our data show that silibinin initiated in SW480 and SW620 cells an autophagic-mediated survival response overwhelmed by the activation of both the extrinsic and intrinsic apoptotic pathways.
Apoptosis 07/2011; 16(10):1042-53. · 4.07 Impact Factor
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ABSTRACT: We previously reported that the chemopreventive agent lupulone induces apoptosis through activation of the extrinsic pathway via TRAIL DR4/DR5 death receptors overcoming SW620 cell resistance to TRAIL. However, the underlying molecular mechanisms remain unknown. Since the mitogen-activated protein kinases (MAPKs), Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) and p38 control fundamental cellular processes such as apoptosis, we determined the role of these MAPKs in lupulone-triggered apoptosis. We analyzed the effects of JNK, ERK and p38 MAPK inhibitors on lupulone-induced apoptosis by flow cytometry using specific antibodies and real-time RT-PCR. Our data showed that among the MAPKs, only p38 played a major role in lupulone-triggered apoptosis. In contrast to JNK and ERK inhibition, the specific inactivation of p38 inhibited the lupulone-triggered up-regulation of p53 and TRAIL-death receptor DR4/DR5 expression, and prevented DNA fragmentation. Lupulone treatment enhanced the expression of the anti-apoptotic Mcl-1 protein by 60% favoring the preservation of mitochondrial integrity. The inactivation of p38 initiated a 50% reduction in Mcl-1, Bcl-2 and Bax expression without changing the Mcl-1/Bax ratio suggesting that p38 was not involved in the protective effect of lupulone on mitochondria. Our data support the view that the lupulone-triggered enhanced expression of p38 plays a major role in the activation of p53 and of the TRAIL-death receptor apoptotic pathway in SW620 human colon cancer-derived metastatic cells.
Oncology Reports 07/2011; 26(1):109-14. · 1.84 Impact Factor
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ABSTRACT: By using the rat azoxymethane (AOM)-induced colon carcinogenesis model, which mirrors many clinical features of human colorectal cancer, we examined whether genetic changes occurring early in colonic mucosa are predictive of treatment efficacy. In the present study the administration of the chemopreventive agent lupulone over the course of 7 weeks postinitiation reduced the number of preneoplastic lesions in the colonic mucosa by 50%. At the molecular level we observed the downregulation of genes involved in the inflammatory response, including IL-1β and TNF-α, and of matrix metalloproteinase-7 gene and protein expression. We also observed a substantial upregulation of components of the innate immune system, α-defensin-5 and lipocalin 2. Lupulone induced the expression of apoptosis-related genes and caused a reversal of the B-cell lymphoma/leukemia 2 (Bcl-2; antiapoptotic) to Bcl-2 associated X protein (Bax; proapoptotic) transcript and protein ratios (Bcl-2/Bax > 1 in AOM controls and Bcl-2/Bax < 1 in lupulone-treated AOM rats). Here, we identify several target genes that could be considered early biomarkers of colon carcinogenesis and indicative of drug efficacy.
Pathology International 02/2011; 61(2):80-7. · 1.62 Impact Factor
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ABSTRACT: The nuclear factor-kappaB (NF-NF-κ) has been shown to upregulate pro-apoptotic mediators such as TRAIL-DR4/-DR5 receptors and the p53 transcription factor depending on the type of stimulus and the cell type involved. Previously, apple procyanidins (Pcy) have been shown to upregulate the expression of TRAIL-DR4/-DR5 and thereby overcoming the resistance of human colon cancer-derived metastatic SW620 cells to TRAIL.
NF-κB and p53 were investigated for their involvement in the Pcy-triggered apoptosis of human derived-metastatic colon cancer (SW620) cells.
Cell death, p53, TRAIL-DR4/-DR5 proteins were analyzed by flow cytometry. DR4/DR5 mRNA was analyzed by RT-PCR in real time. Activated p50/p65 and p53 forms were studied by ELISA and immunoblotting
Pcy-triggered cell death was prevented by specific inhibitors of NF-κB and of p53: amino-4-(4-phenoxy-phenylethylamino) quinazoline (QNZ) and pifithrin α (Pα), respectively. QNZ and Pα inhibited the Pcy-dependent activation of TRAIL-DR4/-DR5 death receptors. However, the upregulation of TRAIL-DR4 by Pcy was significantly decreased only when NF-κB and p53 inhibitors were used in combination; this effect was not observed with a single inhibitor. This effect was not observed for TRAIL-DR5 and suggested that the expression of each TRAIL-death receptor may be regulated differently.
These data suggested that NF-κB and p53 are partially required in Pcy-triggered apoptosis of SW620 cells by up-regulating the expression of TRAIL-DR4/-DR5. In addition, the ratio between TRAIL-DR4/-DR5 may be a determining factor in the activation of TRAIL-death receptor mediated apoptosis.
Biomédica: revista del Instituto Nacional de Salud 12/2010; 30(4):577-86. · 0.55 Impact Factor
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ABSTRACT: The rat azoxymethane (AOM)-induced colon carcinogenesis model provides useful information for understanding human colorectal neoplasia. Here, we used the AOM model to measure the gene expression profiles of biomarkers related to tumor progression. We assessed tumor progression stages by computed tomographic (CT) colonography. Messenger RNAs were isolated from tumors and mucosal samples, and gene expression levels were assessed by real-time quantitative polymerase chain reaction (PCR). We show that early stages of tumor progression are associated with an upregulation of matrix metalloproteinase-7 (MMP-7) and of genes involved in the inflammatory response, including interleukin (IL1beta) and tumor necrosis factor-alpha (TNFalpha). The ratio of B-cell lymphoma/leukemia 2 (Bcl-2)-associated X proteins (Bax) to Bcl-2 transcript (proapototic/antiapoptotic signals) is elevated in early stages of tumor progression (Bax/Bcl-2 >1) and reversed in more advanced stages of tumor development (Bax/Bcl-2 <1). These changes are associated with the reduced expression of TNF-related apoptosis-inducing ligand (TRAIL)-death receptor 5 (DR5) and FAS (also known as CD95) apoptotic receptors. Advanced stages of tumor development are characterized by an increase in MMP-9 expression associated with the upregulation of components of the innate immune system: alpha-defensin 5 (DEF-5) and neutrophil gelatinase-associated lipocalin (NGAL). The identification of specific gene expression profiles that correlate with tumor progression stages, as reported in the present study, may represent an important step in evaluating potential chemopreventive and/or chemotherapeutic agents prior to initiating clinical trials.
International Journal of Oncology 06/2010; 36(6):1485-90. · 2.40 Impact Factor
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ABSTRACT: The SW480 cell line is derived from a human colon adenocarcinoma, and SW620 cells are derived from a lymph node metastasis of the same patient. We have previously shown that lupulone induces apoptosis in SW480 cells, through a cross talk between the TRAIL-death receptor pathway and the mitochondrial apoptotic pathway. In SW620 cells, lupulone induced apoptosis only through TRAIL-death receptor activation. Both cell lines exhibit the same p53 mutations. Because p53 plays a central role in the response to cellular stresses by upregulating the transcription of several genes controlling apoptosis, we aimed to study the involvement of p53 on lupulone-triggered apoptosis. Our data show that in SW620 cells, lupulone upregulated p53 gene expression and caused a cloistering of p53 in the nucleus, allowing p53 to play a proapoptotic role by activating the TRAIL-death receptor pathway. In contrast, in lupulone-treated SW480 cells, p53 was translocated to the cytoplasm where it initiated a survival response associated with the up-regulation of antiapoptotic Bcl-2 and Mcl-1 proteins in an attempt to preserve mitochondrial integrity. These prosurvival effects of p53 in lupulone-treated SW480 cells were reversed by pifithrin-α, an inhibitor of p53 function, which caused a blocking of p53 in the nucleus leading to the down-regulation of Bcl-2 and Mcl-1, the up-regulation of proapoptotic Bax protein and TRAIL-death receptors leading to enhanced cell death. Our data support different functions of the same mutated p53 in colon adenocarcinoma and derived metastatic cells in response to the chemopreventive agent lupulone.
Translational oncology 01/2010; 3(5):286-92. · 3.40 Impact Factor
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ABSTRACT: Flavonoids are polyphenolic compounds able to favour cholesterol-lipid-raft formation and control cell signaling pathways by targeting receptors at the cell surface. Procyanidins (Pcy) are oligomeric and polymeric flavonoids formed by catechins and epicatechins monomers trigger apoptosis by activating TRAIL-death receptors in human colon adenocarcinoma SW480 cells. Here, we investigated whether the apoptotic process triggered by apple procyanidins involving the up-regulation of TRAIL-death receptors DR4/DR5 at the cell surface was dependent on cell membrane lipid-raft formation. We report that Pcy-induced apoptosis was enhanced in presence of nystatin, a cholesterol-sequestering compound inhibiting lipid-raft formation, without changing DR4/DR5 receptor expression. Treatment of SW480 cells with TRAIL caused a 3.5-fold increased level of caveolin together with a 2- to 2.5-fold increased amount of DR4/DR5 proteins in lipid rafts. Pcy-treatment did not induce any alteration in the expression of DR4/DR5 proteins as well as of caveolin present in lipid-raft fractions. Pcy induced an activation of TRAIL-death receptor-mediated apoptosis by a mechanism independent of lipid-raft formation. These results highlight the potential of Pcy as a direct activator of TRAIL-death receptors in cell membrane even in the absence of lipid rafts.
Biochemical and Biophysical Research Communications 09/2009; 388(2):372-6. · 2.48 Impact Factor
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ABSTRACT: Our study aimed to compare death signalling pathways triggered by lupulone in TRAIL-sensitive human colon cancer cells (SW480) and in their derived TRAIL-resistant metastatic cells (SW620). Lupulone (40 microg/ml) up-regulated expression of TRAIL DR4/DR5 death receptors at the cell surface of both cell lines, even in the absence of exogenous TRAIL ligand. Cell death induced by lupulone was inhibited in SW480 and SW620 cells exposed to blocking anti-DR4/DR5 antibodies. In SW480 cells, lupulone triggered cell death through a cross-talk between TRAIL-DR4/DR5 and the mitochondrial (intrinsic) pathways involving caspase-8 activation and Bid protein cleavage. As a consequence mitochondrial cytochrome c was released into the cytosol and activation of caspases-9 and -3 was observed. In the metastatic SW620 cells, lupulone restored the sensibility of these cells to TRAIL ligand and activated the extrinsic apoptotic pathway via DR4/DR5 death receptors and the involvement of the caspase-8/caspase-3 cascade. The demonstration that lupulone is able to activate TRAIL-death signalling pathways even in TRAIL resistant cancer cells highlights the potential of this natural compound for cancer prevention and therapy.
Apoptosis 09/2008; 13(10):1232-42. · 4.07 Impact Factor
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ABSTRACT: The bitter acids of hops (Humulus lupulus L.) mainly consist of humulones or alpha-acids and lupulones or beta-acids. We aimed to evaluate the antiproliferative mechanisms of lupulones on a human metastatic colon carcinoma-derived cell line (SW620 cells) and to assess their chemopreventive effects in a model of colon carcinogenesis. SW620 cell growth was inhibited by 70% after a 48 h exposure to lupulones (40 microg/ml). Lupulones up-regulated the expression of Fas receptor (Fas) and Fas ligand (FasL) as well as TNF-related apoptosis inducing ligand (TRAIL)-R1 (DR4) and -R2 (DR5) receptor proteins, suggesting the involvement of Fas and TRAIL receptors-mediated pathways in lupulone-induced apoptosis. Lupulones also increased the mitochondrial membrane permeability. Colon carcinogenesis was initiated in Wistar rats by intra-peritoneal injections of azoxymethane (AOM), once a week for 2 weeks. One week after the last injection, rats received lupulones (0.001 or 0.005%) in drinking water, and AOM-control rats received the excipient. After 7 months of treatment, the colon of rats receiving 0.001 and 0.005% lupulones showed, respectively, a 30 and a 50% reduction (P < 0.05) of the number of preneoplastic lesions (aberrant crypt foci). In addition, we observed a drastic reduction (70-80%) of the total number of tumors in the colon of rats treated with lupulones when compared with the AOM control group. Lupulones induced apoptosis in SW620 colon-derived metastatic cells by activating both Fas and TRAIL death receptor signaling pathways, and antagonize at a low dose (4 mg/kg/day) colon cancer development. These observations suggest the use of lupulones for colon cancer chemoprevention trials.
Carcinogenesis 07/2007; 28(7):1575-81. · 5.70 Impact Factor
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ABSTRACT: We reported previously that 7beta-hydroxysitosterol and 7beta-hydroxycholesterol induced apoptosis in Caco-2 cells. Apoptosis caused by 7beta-hydroxysitosterol but not by 7beta-hydroxycholesterol was related to a caspase-dependent process. In the present report, we compared the effects of both compounds on mitochondria integrity and on various modulators of apoptosis. When Caco-2 cells were exposed to both hydroxysterols, no changes in Bcl-2 and Bax expressions were detected indicating a Bcl-2/Bax-independent cell death pathway, whereas loss of mitochondrial membrane potential and cytochrome c release were observed. Endonuclease G expression and enhanced production of reactive oxygen species were detected in 7beta-hydroxycholesterol treated cells, but not with 7beta-hydroxysitosterol. Loss of mitochondrial membrane potential and cell death produced by both hydroxysterols were prevented by vitamin C. Lysosomal membrane integrity was altered with both hydroxysterols, but 7beta-hydroxysitosterol was significantly more active on than 7beta-hydroxycholesterol. Both hydroxysterols induced apoptosis by mitochondrial membrane permeabilization. However, 7beta-hydroxycholesterol exhibited a specific enhancement of oxidative stress and of endonuclease G expression despite its closely related chemical structure with 7beta-hydroxysitosterol. The two hydroxysterols exhibit different lipophilic properties which may explain their different biological effects.
APOPTOSIS 02/2007; 12(1):87-96. · 4.79 Impact Factor
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ABSTRACT: 7beta-OHsitosterol and 7beta-OHcholesterol are natural compounds of plant and animal cells with high structural similarity. Recently it was reported that both compounds induced apoptosis on human colon cancer cells by targeting different signalling pathways. Our study aimed at comparing their effects on polyamine metabolism and its relation to apoptosis. When human colon cancer cells were exposed to 7beta-OHsitosterol and to 7beta-OHcholesterol at concentrations inhibiting growth by the same degree, both compounds caused a reduction of polyamine biosynthetic enzyme activity, of the polyamine pools, and an increase of N1-acetylspermidine concentration indicating the enhancement of polyamine catabolism. Exogenous putrescine did not prevent cell death caused by 7beta-OHsitosterol, whereas 7beta-OHcholesterol-induced apoptosis was inhibited. MDL 72527, an inhibitor of polyamine oxidase, an enzyme of the polyamine catabolic pathway, potentiated the antiproliferative effects of 7beta-OHcholesterol by increasing the N1-acetylspermidine pool and enhanced the accumulation of apoptotic cells. In contrast, MDL 72527 did not change the apoptosis rate and the N1-acetylspermidine content in cells treated with 7beta-OHsitosterol. These data indicate that polyamine metabolic perturbations triggered by 7beta-OHcholesterol but not by 7beta-OHsitosterol are related to cell death.
International Journal of Oncology 01/2007; 29(6):1549-54. · 2.40 Impact Factor
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ABSTRACT: Apple procyanidins have chemopreventive properties in a model of colon cancer, they affect intracellular signalling pathways, and trigger apoptosis in a human adenocarcinoma-derived metastatic cell line (SW620). In the present study we investigated relationships between procyanidin-induced alterations in polyamine metabolism and apoptotic effects. Apple procyanidins diminish the activities of ornithine decarboxylase and S-adenosyl-L-methionine decarboxylase, key enzymes of polyamine biosynthesis, and they induce spermidine/spermine N(1)-acetyltransferase, which initiates retroconversion of poly-amines. As a consequence of the enzymatic changes polyamine concentrations are diminished, and N(1)-acetyl-polyamines accumulate in SW620 cells. In contrast with expectations MDL 72527, an inactivator of polyamine oxidase (PAO), improved the anti-proliferative effect of procyanidins, and caused an increase of the proportion of apoptotic cells, although it prevented the formation of hydrogen peroxide and 3-acetamidopropanal, the cytotoxic products of PAO-catalysed degradation of N(1)-acetylspermidine and N1-acetylspermine. Addition of 500 microM N1-acetylspermidine to the culture medium in the presence of procyanidins mimicked the effect of MDL 72527. Therefore we presume that the enhanced procyanidin-triggered apoptosis by MDL 72527 is mediated by the accumulation of N(1)-acetyl-polyamines. The observation that apple procyanidins enhance polyamine catabolism and reduce polyamine biosynthesis activity similar to known inducers of SSAT, without sharing their toxicity, and the potentiation of these effects by low concentrations of MDL 72527 suggests apple procyanidins for chemopreventive and therapeutic interventions.
International Journal of Oncology 09/2006; 29(2):423-8. · 2.40 Impact Factor
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ABSTRACT: MDL 72527 (N1,N4-di-2,3-butadienyl-1,4-butanediamine) is a selective inactivator of polyamine oxidase with therapeutic potential. However, the development of lethal toxic effects due to prevention of spermine degradation is a considerable disadvantage of the compound. Since the cytotoxicity of MDL 72527 was postulated to be independent of its anti-polyamine oxidase activity, its cytotoxicity to cancer cells was compared with that of a close analogue that is devoid of structural features enabling mechanism-based inactivation of polyamine oxidase. N1,N4-di-n-butyl-1,4-butanediamine proved to be a cytotoxic agent of considerable potency, which induces mainly non-apoptotic cell death, whereas MDL 72527 causes under identical conditions both, apoptotic and non-apoptotic cell death. The sensitivity of cells to both compounds is presumably dependent of their glutathione content.
International Journal of Oncology 01/2006; 27(6):1669-76. · 2.40 Impact Factor
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ABSTRACT: Apples contain several classes of polyphenols: monomers (catechins, epicatechins) and oligomers/polymers, such as the procyanidins. Our aim was (i) to study anti-proliferative mechanisms on human metastatic colon carcinoma (SW620 cells) of apple polyphenol fractions (monomers or procyanidins) and (ii) to evaluate their anti-carcinogenic properties in vivo. Two polyphenol-enriched fractions were isolated from apples. Fraction non-procyanidins contained 73% phenolic monomers and no procyanidins, while fraction procyanidins contained 78% procyanidins and no monomers. Inhibition of SW620 cell growth was only observed with fraction P (IC50 = 45 microg/ml). After a 24-h exposure of cells to fraction P, protein kinase C activity was inhibited by 70% and a significant increase in extracellular signal-regulated kinases 1 and 2 and c-jun N-terminal kinases expression was observed together with the down-regulation of polyamine biosynthesis and the activation of caspase-3. Colon carcinogenesis was induced in rats by intraperitoneal injections of azoxymethane, once a week for 2 weeks. Seven days after the last injection, Wistar rats received fraction P (0.01%) dissolved in drinking water. After 6 weeks of treatment, the colon of rats receiving procyanidins showed a significant (P < 0.01) reduction of the number of preneoplastic lesions when compared with controls receiving water. The total number of hyperproliferative crypts and of aberrant crypt foci was reduced by 50% in rats receiving 0.01% apple procyanidins in their drinking water. Our results show that apple procyanidins alter intracellular signaling pathways, polyamine biosynthesis and trigger apoptosis in tumor cells. These compounds antagonize cancer promotion in vivo. In contrast with absorbable drugs, these natural, non toxic, dietary constituents reach the colon where they are able to exert their antitumor effects.
Carcinogenesis 07/2005; 26(7):1291-5. · 5.70 Impact Factor
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ABSTRACT: We investigated on colon cancer cells the effect of geraniol on thymidylate synthase and thymidine kinase expression, two enzymes related to 5-fluorouracil cytotoxicity. The anti-tumoral efficacy of geraniol and 5-fluorouracil were also evaluated on TC-118 human tumors transplanted in Swiss nu/nu mice. Geraniol (150 microM) but not 5-fluorouracil caused a 2-fold reduction of thymidylate synthase and thymidine kinase expression in cancer cells. In nude mice, the combined administration of 5-fluorouracil (20 mg/kg) and geraniol (150 mg/kg) caused a 53% reduction of the tumor volume, whereas a 26% reduction was obtained with geraniol alone, 5-fluorouracil alone showed no effect.
Cancer Letters 12/2004; 215(1):53-9. · 4.24 Impact Factor
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ABSTRACT: When SW620 colon cancer-derived metastatic cells were exposed to nanomolar concentrations of Taxol, colchicine or (Z)-3,5,4'-trimethoxystilbene (R3), huge aneuploid, polynuclear cells survived the treatment. These cells released considerable amounts of the matrix metalloproteinase matrilysin (MMP-7), and tissue-type plasminogen activator (tPA) into the surrounding culture medium. MMP-7, and other proteolytic enzymes were highly expressed by these cells. In spite of their enormous size, the polyploid cells exhibited a considerable migratory capacity, as was demonstrated by their migration through an artificial basement membrane. While colchicine and R3-treated cells showed an inverse relationship between drug concentration and invasiveness, treatment with Taxol increased the capacity of the SW620 cells to penetrate through the membrane. The invasive capacity was not correlated with the induction and release of proteolytic enzymes. The idea that expression and release of proteolytic enzymes is a fundamental prerequisite of tumour cell invasiveness is generally accepted. The ability of the cells to respond to chemotactic signalling, and the filamentous structures of the cells, together with several cell adhesion factors, which are the basis of cell migration, are prerequisites of invasiveness. These factors are presumably different in the aneuploid cells produced by Taxol, colchicine and R3, and await scrutiny.
International Journal of Oncology 11/2004; 25(4):1039-48. · 2.40 Impact Factor
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Jordane Biarc,
Isabelle S Nguyen,
Annelise Pini, Francine Gossé,
Sophie Richert,
Danielle Thiersé,
Alain Van Dorsselaer,
Emmanuelle Leize-Wagner,
Francis Raul,
Jean-Paul Klein,
Marie Schöller-Guinard
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ABSTRACT: Several studies reported linkage between bacterial infections and carcinogenesis. Streptococcus bovis was traditionally considered as a lower grade pathogen frequently involved in bacteremia and endocarditis. This bacterium became important in human health as it was shown that 25-80% of patients who presented a S.bovis bacteremia had also a colorectal tumor. Moreover, in previous experiments, we demonstrated that S.bovis or S.bovis wall extracted antigens (WEA) were able to promote carcinogenesis in rats. The aim of the present study was: (i) to identify the S.bovis proteins responsible for in vitro pro-inflammatory properties; (ii) to purify them; (iii) to examine their ability to stimulate in vitro IL-8 and COX-2 expression by human colon cancer cells; and (iv) to assess in vivo their pro-carcinogenic potential in a rat model of colon carcinogenesis. The purified S300 fraction, as determined by proteomic analysis, contained 72 protein spots in two-dimensional gel electrophoresis representing 12 different proteins able to trigger human epithelial colonic Caco-2 cells and rat colonic mucosa to release CXC chemokines (human IL-8 or rat CINC/GRO) and prostaglandins E2, correlated with an in vitro over-expression of COX-2. Moreover, these proteins were highly effective in the promotion of pre-neoplastic lesions in azoxymethane-treated rats. In the presence of these proteins, Caco-2 cells exhibited enhanced phosphorylation of the three classes of MAP kinases. Our results show a relationship between the pro-inflammatory potential of S.bovis proteins and their pro-carcinogenic properties, confirming the linkage between inflammation and colon carcinogenesis. These data support the hypothesis that colonic bacteria can contribute to cancer development particularly in chronic infection/inflammation diseases where bacterial components may interfere with cell function.
Carcinogenesis 09/2004; 25(8):1477-84. · 5.70 Impact Factor
