pectins and Colonic-Neoplasms

The intake of dietary fibers has been associated with a reduction in the risk of colorectal cancer. Pectins - a class of dietary fibers - are polysaccharides that have a complex structure with a wide range of direct and indirect biological beneficial effects on humans. Direct effects include dilution of carcinogens, reduction in cholesterol levels, and interaction with immune cells. Indirect effects include the fermentation and production of short-chain fatty acids. All these biological effects have implications for colon cancer development; however, the exact mechanisms are not fully understood. In this review, we explore the clinical trials regarding dietary fibers and colorectal cancer, thus indicating the potential anti-cancer effects of pectins and modified pectins. We focused on the emerging biological effects of pectins through targeting colorectal cancer hallmark effects and the enabling characteristics. We provide an overview of the mechanisms for each hallmark capability and how the different pectins might exert that anti-cancer effect, such as induction of apoptosis, reduction in cancer cell proliferation and metastasis. The data compilation described herein can guide future clinical trials to investigate how to target specific pectin structures to act as an adjuvant in colon cancer treatment.

Topics: Colonic Neoplasms; Dietary Fiber; Fatty Acids, Volatile; Humans; Pectins; Polysaccharides

Colon cancer is one of the most prevalent diseases, and traditional chemotherapy has not been proven beneficial in its treatment. It ranks second in terms of mortality due to all cancers for all ages. Lack of selectivity and poor biodistribution are the biggest challenges in developing potential therapeutic agents for the treatment of colon cancer. Nanoparticles hold enormous prospects as an effective drug delivery system. The delivery systems employing the use of polymers, such as chitosan and pectin as carrier molecules, ensure the maximum absorption of the drug, reduce unwanted side effects and also offer protection to the therapeutic agent from quick clearance or degradation, thus allowing an increased amount of the drug to reach the target tissue or cells. In this systematic review of published literature, the author aimed to assess the role of chitosan and pectin as polymer-carriers in colon targeted delivery of drugs in colon cancer therapy. This review summarizes the various studies employing the use of chitosan and pectin in colon targeted drug delivery systems.

Topics: Antineoplastic Agents; Chitosan; Colon; Colonic Neoplasms; Drug Carriers; Drug Delivery Systems; Humans; Pectins; Tissue Distribution

Colon cancer is the fourth most common cancer globally with 639,000 deaths reported annually. Typical chemotherapy is provided by injection route to reduce tumor growth and metastasis. Recent research investigates the oral delivery profiles of chemotherapeutic agents. In comparison to injection, oral administration of drugs in the form of a colon-specific delivery system is expected to increase drug bioavailability at target site, reduce drug dose and systemic adverse effects. Pectin is suitable for use as colon-specific drug delivery vehicle as it is selectively digested by colonic microflora to release drug with minimal degradation in upper gastrointestinal tract. The present review examines the physicochemical attributes of formulation needed to retard drug release of pectin matrix prior to its arrival at colon, and evaluate the therapeutic value of pectin matrix in association with colon cancer. The review suggests that multi-particulate calcium pectinate matrix is an ideal carrier to orally deliver drugs for site-specific treatment of colon cancer as (1) crosslinking of pectin by calcium ions in a matrix negates drug release in upper gastrointestinal tract, (2) multi-particulate carrier has a slower transit and a higher contact time for drug action in colon than single-unit dosage form, and (3) both pectin and calcium have an indication to reduce the severity of colon cancer from the implication of diet and molecular biology studies. Pectin matrix demonstrates dual advantages as drug carrier and therapeutic for use in treatment of colon cancer.

Topics: Administration, Oral; Antineoplastic Agents; Colon; Colonic Neoplasms; Drug Carriers; Drug Delivery Systems; Humans; Pectins; Pharmaceutical Vehicles

Dietary fiber is described as the proportion of plant foods not digested in the human small intestine. Among the various kinds of pectin, apple pectin exerts a bacteriostatic action and therefore may change the composition of the intestinal flora. The diet supplemented with 20% apple pectin significantly decreased the number and the incidence of AOM-induced colon tumors in rats. The prostaglandin E2 (PGE2) level in the distal colonic mucosa and blood of portal vein was lower in rats fed 20% pectin than those fed the basal diet. The ability of apple pectin to decrease PGE2 was dose-dependent and those results suggest an anti-inflammatory effect in the bowel. Rats fed apple pectin showed a significantly lower incidence of hepatic metastasis than those fed the basal diet. To determine whether the anti-inflammatory effect of Lactobacillus on hepatic metastasis model same as apple pectin, Lactobacillus casei was selected. Metastatic nodules were significantly reduced, especially in the group receiving pretreatment. Apple pectic oligosaccharides with small molecular weights showed highly inhibitory effects on hypoxanthin-xanthin oxidase and ferrous sulfate-hydrogen peroxide. The scavenging activity of apple pectic oligosaccharides was suitable and accelerated at high temperatures (120 degrees C, 30 min.). Apple pectin and Lactobacillus have a scavenger effect in the intestinal digestion and portal circulation system as an anti-inflammatory food and have very important function for the prevention of hepatic metastasis.

Topics: Animals; Antioxidants; Colonic Neoplasms; Dietary Fiber; Dinoprostone; Free Radical Scavengers; Humans; Intestinal Mucosa; Lacticaseibacillus casei; Liver Neoplasms; Pectins; Rats; Rosales

The gastrointestinal tract contains a unique microecology. Microorganisms living in the mouth, stomach, and most importantly in the small and large intestines produce enzymes which help metabolize certain ingested foods, as well as maintain important body homeostatic mechanisms such as the bile salt enterohepatic circulation. Recent awareness of the importance of poorly digested foods such as cellulose, hemicellulose, pectins, and lignins, as well as selectively absorbed long-chain polysaccharides, has stressed the importance of the relationship of food to the microflora. This intestinal microecology has definite effects on the human host in cholesterol metabolism, glucose tolerance, and may explain such diseases as carcinoma. The exacting details of the intestinal microecology need further elaboration.

Topics: Bile Acids and Salts; Body Water; Calcium; Cellulose; Cholesterol, Dietary; Colon; Colonic Neoplasms; Diabetes Mellitus; Dietary Fiber; Digestive System; Food Analysis; Gastric Acid; Homeostasis; Humans; Iron Deficiencies; Japan; Pectins; Zinc

Intake of bulk vegetable material has diminished in the western countries considerably since the beginning of industrialisation. Lack of bulk substances is being held responsible lately for the increase of diseases of the gastrointestinal tract. It has been shown, that bulk materials increased stool weight and decreased gastrointestinal passage time; it is assumed, that they do have beneficial effects in the treatment of diverticulosis of the colon. It is still controversial, how bulk materials influence mineral metabolism, especially intestinal resorption of iron, calcium and other bivalent cations. Hypocholesterinemic effects of lignin and pectin, which form part of vegetable bulk food, are as yet not well defined. The question is still open, if bulk foods do have prophylactic effects in regard to carcinoma of the colon.

Topics: Anticholesteremic Agents; Bile Acids and Salts; Cellulose; Colonic Neoplasms; Dietary Fiber; Diverticulum; Humans; Lignin; Pectins; Peristalsis; Plants, Edible

It has been postulated that dietary fiber's protective effect against the development of colon cancer, diverticular disease, and atherosclerosis may be due to the adsorption and/or dilution of intestinal sterols such as bile acids and neural sterols and their bacterial metabolites by component(s) of fiber. Dietary fiber is made up of four major components-cellulose, hemicellulose, lignin, and pectin. There is evidence that hemicellulose and pectin may induce an increase in fecal bile acid excretion in man which may be accompanied by a decrease in serum cholesterol. Natural fibers, such as rolled oats, alfalfa, guar gum, and Bengal gram have been shown to have hypocholesterolemic properties of alfalfa, wheat straw, and some other fibers found considerable amounts of bile acids in vitro. On the other hand, wheat bran, oat hulls, and all the synthetic fibers tested bound only negligible amounts of bile acids under the same conditions. Vegetarians in the United States have lower plasma lipids and different plasma lipoprotein patterns than those of comparable control populations on regular mixed diet. They also have smaller daily fractional turnover rates of cholic acid and deoxycholic acid pool size. In addition, populations on a mixed Western diet, where the rate of large bowel cancer is high (North American, English, Scottish, etc.) degraded and excreted cholesterol and bile acid metabolites to a greater degree than populations where the rate of colon cancer is comparatively low (Ugandan, Japanese, etc). It cannot be denied that the fiber theory linking fiber deficiency with the development of colon cancer and other diseases, is simple, attractive and appears to be firmly based in common sense. When subjected to research studies, however, the situation appears much more complex than expected. Although some progress is being made, the data are often contradictory and confusing, probably due to lack of adequate documentation of fiber intake (e.g., use of dietary fiber instead of crude fiber) and/or the absence of detailed information on the chemistry of the fiber itself.

Topics: Adult; Bile Acids and Salts; Cellulose; Colonic Neoplasms; Diet, Vegetarian; Dietary Fiber; Digestion; Feces; Humans; Intestines; Lignin; Male; Pectins; Polysaccharides

The calcium pectinate (CaP) capsule, a novel, colon-specific delivery system, was designed and developed using 5-fluorouracil (5-FU) as a model drug. Technically, CaP capsules were prepared by dipping a glass or stainless steel rod successively into pectin and calcium chloride solutions, followed by subsequent air-drying and coating. In vitro studies showed that the release of 5-FU from CaP capsules markedly increased in the presence of rat cecal contents, and the release characteristic was mainly associated with some capsule parameters such as calcium content, shell thickness, and coat amount. Gamma scintigraphic studies demonstrated that CaP capsules could pass through the stomach and small intestine intact and could release drug in colon. The 5-FU releasing characteristics acquired both from in vitro biomimic dissolution experiments and from healthy volunteers indicated that the newly developed CaP capsule possessed the ideal colon-specific drug delivery characteristic.

Topics: Administration, Oral; Adult; Animals; Antineoplastic Agents; Capsules; Cecum; Colon; Colonic Neoplasms; Drug Delivery Systems; Fluorouracil; Humans; Male; Pectins; Radionuclide Imaging; Rats; Solubility

Colorectal cancer was inducted in Wister rats using titanium dioxide nanoparticles (TiO

Topics: Animals; Apoptosis; Cell Line, Tumor; Colonic Neoplasms; Curcumin; Dimethylhydrazines; Fluorouracil; Pectins; Rats; Rats, Wistar; Spectroscopy, Fourier Transform Infrared; Titanium

Colon cancer is a most common malignant cancer in digestive system, and it is prone to develop resistance to the commonly used chemotherapy drugs, leading to local recurrence and metastasis. Paris saponin VII (PSVII) could not only inhibit the proliferation of colon cancer cells but also effectively induce apoptosis of drug-resistant colon cancer cells and reduce the metastasis of drug-resistant colon cancer cells as well. However, PSVII was insoluble in water and fat. It displayed no selective distribution in body and could cause severe hemolysis. Herein, colon cancer targeting calcium phosphate nanoparticles were developed to carry PSVII to treat drug-resistant colon cancer.. PSVII carboxymethyl-β-cyclodextrin inclusion compound was successfully encapsulated in colon cancer targeting calcium phosphate nanoparticles (PSVII@MCP-CaP) by using modified citrus pectin as stabilizer agent and colon cancer cell targeting moiety. PSVII@MCP-CaP significantly reduced the hemolysis of PSVII. Moreover, by specific accumulating in orthotopic drug-resistant colon cancer tissue, PSVII@MCP-CaP markedly inhibited the growth of orthotopic drug-resistant colon cancer in nude mice. PSVII@MCP-CaP promoted the apoptosis of drug-resistant colon cancer cells through mitochondria-mediated apoptosis pathway. Moreover, PSVII@MCP-CaP significantly inhibited the invasion and migration of drug-resistant colon cancer cells by increasing E-cadherin protein expression and reducing N-cadherin and MMP-9 protein expression.. PSVII@MCP-CaP has great potential in the treatment of drug-resistant colon cancer. This study also explores a new method to prepare active targeting calcium phosphate nanoparticles loaded with a fat and water insoluble compound in water.

Topics: Animals; Antineoplastic Agents; Apoptosis; Calcium Phosphates; Cell Proliferation; Colonic Neoplasms; Drug Resistance, Neoplasm; Mice; Mice, Nude; Nanoparticle Drug Delivery System; Nanoparticles; Pectins; Saponins

The biological activity of apple pectin extracted conventionally or enzymatically using endo-xylanase and endo-cellulase, was tested in vitro. The analyses were performerd in tetraplicates and the statistical significance of the differences were assessed using ANOVA, Tukey post hoc and LSD (the least significant difference) tests. Multivariate regression analysis was applied to determine the structural components that have a crucial importance for antioxidant and antitumor properties of pectins. The pectins extracted by enzymes contained up to four times more ferulic acid and showed twice as great ability to neutralize free radicals and Fe(III) reduction. The antiradical potential positively correlated with phenols, fucose and rhamnose content. In the assays performed on HT-29 human adenocarcinoma and B16F10 melanoma cell cultures, the "green" pectins, contrary to acid isolated ones, exhibited remarkable anti-neoplastic potential while being nontoxic to nontransformed L929 cell line. The pectins in the dose of 1 mg/mL were capable of inhibiting adhesion (max 23.1%), proliferation (max 40.4%), invasion (max 76.9%) and anchorage-independent growth (max 90%) of HT-29 cells (significance level

Topics: Antineoplastic Agents; Antioxidants; Apoptosis; Cell Proliferation; Cellulase; Colonic Neoplasms; Endo-1,4-beta Xylanases; Humans; Malus; Melanoma; Pectins; Tumor Cells, Cultured

The water-soluble fractions of pectin extracted from the pulp of ripe papayas have already been found to exert positive effects on cancer cell cultures. However, the mechanisms that lead to these beneficial effects and the pectin characteristics that exert these effects are still not well understood. Characteristics such as molecular size, monosaccharide composition and structural conformation are known as polysaccharide factors that can cause alterations in cellular response. During fruit ripening, a major polysaccharide solubilization, depolymerization, and chemical modification occur. The aims of this work are to fractionate the pectin extracted from the pulp of papayas at two stages of ripening (fourth and ninth day after harvesting) into uronic and neutral fractions and to test them for the inhibition of human recombinant galectin-3 and the inhibition of colon cancer cell growth. The structures of the fractions were chemically characterized, and the uronic fraction extracted from the fourth day after harvesting presented the best biological effects across different concentrations in both galectin-3 inhibition and viability assays. The results obtained may help to establish a relationship between the chemical structures of papaya pectins and the positive in vitro biological effects, such as inhibiting cancer cell growth.

Topics: Blood Proteins; Carica; Cell Proliferation; Cell Survival; Cell Wall; Colonic Neoplasms; Down-Regulation; Galectins; Gene Expression Regulation, Neoplastic; HCT116 Cells; HT29 Cells; Humans; Pectins; Polysaccharides; Uronic Acids

Two modified citrus pectins, MCP4 and MCP10, were prepared by UV/H

Topics: Acids; Alkalies; Anti-Inflammatory Agents; Antineoplastic Agents; Caco-2 Cells; Colonic Neoplasms; Humans; Hydrogen Peroxide; In Vitro Techniques; Inflammation; Inflammation Mediators; Pectins; Ultraviolet Rays

Fruits are a prime source of nutrients, bioactive compounds, and dietary fibers. Some products available on the Brazilian market use fruit by-products and claim to have useful effects on human health due to their dietary fiber content. The study aimed to extract and purify the total (28-47 w/w yield) and soluble dietary fiber (4-7 w/w yield) from jaboticaba, papaya, and plum commercial flours sold in Brazil and to study the in vitro biological effects of the fractions. The purified water-soluble fractions consisted mainly of pectin-derived oligosaccharides (5-15 KDa molecular weight) with a negligible content of polyphenols, protein, ashes, and starch. Jaboticaba sample was 95% galacturonic acid while plum and papaya samples were 40% galacturonic acid and 40% galactose (mol%), approximately. The samples were tested for recombinant human galectin-3 inhibition and changes in the cell viability of human colorectal cancer cells. Only the jaboticaba sample inhibited galectin-3 and decreased HCT116 cell viability after 48 h of treatment (p ≤ 0.01) while the plum sample decreased the cell viability after 24 h treatment (p ≤ 0.05). The results obtained in this study demonstrate the relationship between the structure of the soluble fibers extracted from jaboticaba flour and the possible beneficial effects of their consumption.

Topics: Brazil; Cell Line, Tumor; Colonic Neoplasms; Flour; Fruit; Galectin 3; Humans; Pectins

In the present study, we successfully developed a cetuximab-conjugated modified citrus pectin-chitosan nanoparticles for targeted delivery of curcumin (Cet-MCPCNPs) for the treatment of colorectal cancer. In vitro analyses revealed that nanoparticles were spherical with size of 249.33 ± 5.15 nm, a decent encapsulation efficiency (68.43 ± 2.4%) and a 'smart' drug release profile. 61.37 ± 0.70% of cetuximab was adsorbed to the surface of the nanoparticles. Cellular uptake studies displayed enhanced internalization of Cet-MCPCNPs in Caco-2 (EGFR +ve) cells, which ultimately resulted in a significant reduction in cancer cell propagation. The cell cycle analysis indicated that Cet- MCPCNPs induced cell death in enhanced percentage of Caco-2 cells by undergoing cell cycle arrest in the G2/M phase. These data suggest that Cet-MCPCNPs represent a new and promising targeting approach for the treatment of colorectal cancer.

Topics: Antineoplastic Agents; Caco-2 Cells; Cell Cycle Checkpoints; Cell Line, Tumor; Cetuximab; Chitosan; Colonic Neoplasms; Curcumin; Drug Delivery Systems; Drug Liberation; G2 Phase Cell Cycle Checkpoints; HCT116 Cells; Humans; Nanoparticles; Pectins

Colorectal cancer has an overexpression of galectin-3 that is related to cancer progression. A decreased risk of colon cancer can be related to consumption of dietary fibers, but the entire mechanism by which this protection occurs remains unclear. Pectin is a type of dietary fiber that possesses β-galactosides and can bind and inhibit galectin-3-mediated effects. Papaya fruit has a massive cell wall disassembling during ripening that naturally changes its pectin structure. Our work shows that different points in the ripening time of papaya fruit exhibit pectins (chelate-soluble fractions; CSF) that can or cannot inhibit galectin-3. The fraction that inhibits galectin-3 (3CSF) also diminishes the proliferation of colon cancer cell lines, and it is derived from an intermediate point of papaya ripening. Therefore, we related this to a papaya pectin structure-dependent effect, and the papaya fruit seems to have a pectin structure that is promising in decreasing the risk of colon cancer development.

Topics: Animals; Carbon-13 Magnetic Resonance Spectroscopy; Carica; Cell Proliferation; Cell Survival; Chelating Agents; Colonic Neoplasms; Fruit; Galectin 3; HCT116 Cells; Hemagglutination; HT29 Cells; Humans; Molecular Weight; Pectins; Proton Magnetic Resonance Spectroscopy; Rabbits; Solubility; Time Factors

To examine the anti-metastatic activities of polysaccharides in broccoli, purified polysaccharides (BCE-I, -II, and -III) were isolated by fractionation of broccoli enzyme extracts and subsequent ethanol precipitation. BCE-I mainly consisted of galactose and arabinose, whereas BCE-II mainly consisted of galacturonic acid and rhamnose, and BCE-III mainly consisted of rhamnose and galactose. Of the three fractions, stimulation of murine peritoneal macrophages by BCE-I showed the greatest enhancement of tumor necrosis factor-α, interleukin (IL)-12, and IL-6 secretion. In addition, intravenous (i.v.) administration of BCE-I enhanced the lethal activity of natural killer (NK) cells on YAC-1 tumor cells significantly and dose-dependently in an

Topics: Animals; Antineoplastic Agents, Phytogenic; Brassica; Colonic Neoplasms; Female; Humans; Immunity, Innate; Interleukin-12; Interleukin-6; Killer Cells, Natural; Lung Neoplasms; Macrophage Activation; Macrophages, Peritoneal; Mice; Mice, Inbred BALB C; Neoplasm Metastasis; Pectins; Plant Extracts; Polysaccharides

Curcumin, the active ingredient of the rhizome curcuma longa has been extensively studied as an anticancer agent for various types of tumours. However, its efficacy as an anticancer agent is restricted due to poor absorption from the gastrointestinal tract, rapid metabolism and degradation in acidic medium. In the present study, we encapsulated curcumin in chitosan-pectinate nanoparticulate system (CUR-CS-PEC-NPs) for deployment of curcumin to the colon, whereby curcumin is protected against degradative effects in the upper digestive tract, and hence, maintaining its anticancer properties until colon arrival. The CUR-CS-PEC-NPs was taken up by HT-29 colorectal cancer cells which ultimately resulted in a significant reduction in cancer cell propagation. The anti-proliferative effect of the encapsulated curcumin was similar to that of free curcumin at equivalent doses which confirms that the encapsulation process did not impede the anticancer activity of curcumin. The oral bioavailability (C

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Line; Cell Survival; Chitosan; Colonic Neoplasms; Curcumin; Drug Carriers; Drug Liberation; Drug Stability; Humans; Male; Nanoparticles; Pectins; Rats, Sprague-Dawley

Green cincau (

Topics: Anticarcinogenic Agents; Apoptosis; Caco-2 Cells; Cell Differentiation; Cell Survival; Cellulose; Colonic Neoplasms; Dietary Fiber; Fatty Acids, Volatile; Feces; Fermentation; Gastrointestinal Microbiome; Gram-Negative Aerobic Bacteria; Gram-Positive Bacteria; Humans; Indonesia; Inulin; Lamiaceae; Pectins; Plant Extracts; Plant Leaves; Prebiotics

In this paper, pectin was cross-linked by a coupling reaction with either thioglycolic acid or cystamine dihydrochloride to form thiolated pectins. The thiolated pectins were then coupled with doxorubicin (DOX) derivative to obtain thiolated pectin-DOX conjugates by two different methods, disulfide bond formation and disulfide bond exchange. The disulfide bond exchange method provided a simple, fast, and efficient approach for synthesis of thiolated pectin-DOX conjugates, compared to the disulfide bond formation. Characteristics, physicochemical properties, and morphology of thiolated pectins and thiolated pectin-DOX conjugates were determined. DOX content in thiolated pectin-DOX conjugates using low methoxy pectin was found to be higher than that using high methoxy pectin. The in vitro anticancer activity of thiolated pectin-DOX conjugates was significantly higher than that of free DOX, in mouse colon carcinoma and human bone osteosarcoma cells, but insignificantly different from that of free DOX, in human prostate cancer cells. Due to their promising anticancer activity in mouse colon carcinoma cells, the thiolated pectin-DOX conjugates might be suitable for building drug platform for colorectal cancer-targeted delivery of DOX.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Colonic Neoplasms; Cross-Linking Reagents; Doxorubicin; Drug Carriers; Humans; Male; Mice; Osteosarcoma; Pectins; Sulfhydryl Compounds

The aim of this study was to characterize a polysaccharide found in citrus peels with an anti-metastatic property. CPE-II was purified by the pectinase digestion of citrus peels. During in vivo lung metastasis of Colon26-M3.1, administration of 10μg of CPE-II per mouse showed 81.3% inhibition of metastasis. CPE-II consists of 15 different monosaccharides and 22 different glycosyl linkages, characteristic of rhamnogalacturonan II (RG-II). The primary structure was elucidated based on sugar composition, methylation analysis, oligosaccharide analysis, and sequencing using GC, GC-MS, LC-MS, and ESI-MS/MS analyses. Sequential degradation using partial acid hydrolysis indicated that CPE-II contained Rhap-(1→5)-Kdo, Araf-(1→5)-Dha, an AceA-containing nonasaccharide, and an uronic acid-rich oligosaccharide in addition to an α-(1→4)-galacturono-oligosaccharide main chain. The molecular weight of CPE-II was observed to decrease from 9 to 5kDa at a pH value of <2.0, as observed by HPSEC. Thus, we propose that the anti-metastatic CPE-II is primarily present as an RG-II dimer.

Topics: Animals; Antineoplastic Agents, Phytogenic; Carbohydrate Conformation; Cell Line, Tumor; Citrus; Colonic Neoplasms; Female; Fruit; Lung Neoplasms; Mice, Inbred BALB C; Neoplasm Transplantation; Pectins; Polygalacturonase

Colon cancer is one of the most common internal malignancies, and conventional chemotherapy is not effective in its treatment. Nanoparticles hold tremendous potential as an effective drug delivery system. The physicochemical properties of β-lactoglobulin, the main whey protein of cow's milk, such as its stability at low pH, its resistance to gastric protease, and its ability to bind hydrophobic ligands, give it potential for transporting drugs specifically for colon cancer. In the present research, β-lactoglobulin-pectin nanoparticles were designed to transfer a newly synthesized, anticancer platinum complex (bipyridine ethyl dithiocarbamate Pt(II) nitrate), to the colon. The effects of multiple factors on the size and the colloidal stability of the nanoparticles were studied using dynamic light scattering and scanning electron microscopy techniques. Results showed that the best particle size and highest colloidal stability were obtained in phosphate buffer, pH 4.5, with 0.5 mg/mL β-lactoglobulin and 0.025-0.05wt% pectin. The drug release profile in simulated gastrointestinal conditions demonstrated that β-lactoglobulin with a secondary coating is stable in acidic conditions but is able to release its cargo at pH 7. Hence, these nanoparticles have potential to serve as novel and effective vehicles for oral drug delivery preparations.

Topics: Administration, Oral; Antineoplastic Agents; Cell Line, Tumor; Colonic Neoplasms; Humans; Hydrogen-Ion Concentration; Lactoglobulins; Microscopy, Electron, Scanning; Nanoparticles; Osmolar Concentration; Particle Size; Pectins; Platinum

New pectin derivative (Pec-MA) was obtained in specific reaction conditions. The presence of maleoyl groups in Pec-MA structure was confirmed by (1)H NMR and FTIR spectroscopy. The substitution degree of Pec-MA (DS=24%) was determined by (1)H NMR. The properties of Pec-MA were investigated through WAXS, TGA/DTG, SEM and zeta potential techniques. The Pec-MA presented amorphous characteristics and higher-thermal stability compared to raw pectin (Pec). In addition, considerable morphological differences between Pec-MA and Pec were observed by SEM. The cytotoxic effect on the Caco-2 cells showed that the Pec-MA significantly inhibited the growth of colon cancer cells whereas the Pec-MA does not show any cytotoxic effect on the VERO healthy cells. This result opens new perspectives for the manufacture of biomaterials based on Pec with anti-tumor properties.

Topics: Animals; Antineoplastic Agents; Caco-2 Cells; Cell Proliferation; Cell Survival; Chlorocebus aethiops; Colonic Neoplasms; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Humans; Molecular Structure; Pectins; Structure-Activity Relationship; Vero Cells

Increased intake of probiotic dietary fibre reduces colonic cancer risk. Modified citrus pectin (MCP) requires optimal bioactivity to inhibit galectin-3 (GAL-3) and vascular endothelial growth factor (VEGF). This study evaluated the preventative effect of modified pectin alginate (MCPA) probiotic microbeads on azoxymethane (AOM)-induced colonic carcinogenesis in Balb/c mice.. Optimization of AOM dose duration: 10-15 mg/kg was administered for 2-4 weeks. The optimal AOM dose was initiated prior to intake of MCPA, alginate probiotic (AP) microbeads and MCP in Balb/c mice for 16 weeks; samples were analyzed for colonic histopathology and immunohistochemistry.. AOM at 15 mg/kg for 4 weeks induced optimal GAL-3 and VEGF immunostaining. Furthermore, MCPA treatment reduced GAL-3 expression in the colon of AOM-treated mice compared to MCP.. MCPA probiotic microbeads increase bioactivity and chemopreventative effect against pre-cancerous colonic lesions and adenocarcinoma through inhibition of GAL-3 and VEGF in the Balb/c mouse model of colonic carcinogenesis.

Topics: Alginates; Animals; Azoxymethane; Carcinogenesis; Chemoprevention; Colon; Colonic Neoplasms; Disease Models, Animal; Galectins; Glucuronic Acid; Hexuronic Acids; Immunohistochemistry; Male; Mice, Inbred BALB C; Pectins; Probiotics; Vascular Endothelial Growth Factor A

Pectin modified with pH, heat or enzymes, has previously been shown to exhibit anti-cancer activity. However, the structural requirements for modified pectin bioactivity have rarely been addressed. In this study several pectin extracts representing different structural components of pectin were assessed for effects against colon cancer cells. Rhamnogalacturonan I (RGI) extracts reduced proliferation of DLD1 and HCT116 colon cancer cells in a dose- and time-dependent manner. RGI reduced ICAM1 gene expression and siRNA-mediated knockdown of ICAM1 expression decreased cell proliferation providing a potential novel mechanism for the anti-cancer activity of pectin. Structural analysis of bioactive and non-bioactive RGIs suggested that a homogalacturonan component is maybe essential for the anti-proliferative activity, furthering the understanding of the structural requirements for pectin bioactivity.

Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Colonic Neoplasms; HCT116 Cells; Humans; Intercellular Adhesion Molecule-1; Magnetic Resonance Spectroscopy; Pectins; RNA Interference; RNA, Small Interfering

We have shown that dietary fish oil is protective against experimentally induced colon cancer, and the protective effect is enhanced by coadministration of pectin. However, the underlying mechanisms have not been fully elucidated. We hypothesized that fish oil with butyrate, a pectin fermentation product, protects against colon cancer initiation by decreasing cell proliferation and increasing differentiation and apoptosis through a p27(Kip1)-mediated mechanism. Rats were provided diets of corn or fish oil, with/without butyrate, and terminated 12, 24, or 48 hours after azoxymethane (AOM) injection. Proliferation (Ki-67), differentiation (Dolichos Biflorus Agglutinin), apoptosis (TUNEL), and p27(Kip1) (cell-cycle mediator) were measured in the same cell within crypts in order to examine the coordination of cell cycle as a function of diet. DNA damage (N(7)-methylguanine) was determined by quantitative IHC analysis. Dietary fish oil decreased DNA damage by 19% (P = 0.001) and proliferation by 50% (P = 0.003) and increased differentiation by 56% (P = 0.039) compared with corn oil. When combined with butyrate, fish oil enhanced apoptosis 24 hours after AOM injection compared with a corn oil/butyrate diet (P = 0.039). There was an inverse relationship between crypt height and apoptosis in the fish oil/butyrate group (r = -0.53, P = 0.040). The corn oil/butyrate group showed a positive correlation between p27(Kip1) expression and proliferation (r = 0.61, P = 0.035). These results indicate the in vivo effect of butyrate on apoptosis and proliferation is dependent on dietary lipid source. These results demonstrate the presence of an early coordinated colonocyte response by which fish oil and butyrate protects against colon tumorigenesis.

Topics: Animals; Apoptosis; Azoxymethane; Butyrates; Cell Differentiation; Cell Proliferation; Colon; Colonic Neoplasms; Corn Oil; Cyclin-Dependent Kinase Inhibitor p27; Dietary Fats, Unsaturated; DNA Damage; Fermentation; Fish Oils; Humans; Immunohistochemistry; In Situ Nick-End Labeling; Ki-67 Antigen; Male; Pectins; Rats; Rats, Sprague-Dawley

Calcium, phytic acid, polyphenols and fiber are major inhibitors of iron absorption and they could be found in excess in some diets, thereby altering or modifying the iron nutrition status. The purpose of this study is to evaluate the effect of calcium, tannic acid, phytic acid, and pectin over iron uptake, using an in vitro model of epithelial cells (Caco-2 cell line). Caco-2 cells were incubated with iron (10-30 μM) with or without CaCl2 (500 and 1,000 μM) for 24 h. Then, cells were challenged with phytic acid (50-150 μM); pectin (50-150 nM) or tannic acid (100-500 μM) for another 24 h. Finally, (55)Fe (10 μM) uptake was determined. Iron dialyzability was studied using an in vitro digestion method. Iron uptake in cells pre-incubated with 20 and 30 μM Fe was inhibited by CaCl2 (500 μM). Iron uptake decreased in cells cultured with tannic acid (300 μM) and CaCl2 (500-1,000 μM) (two-way ANOVA, p = 0.002). Phytic acid also decreased iron uptake mainly when cells were treated with CaCl2 (1,000 μM) (two-way ANOVA; p < 0.05). Pectin slightly decreased iron uptake (p = NS). Iron dialyzability decreased when iron was mixed with CaCl2 and phytic or tannic acid (T test p < 0.0001, for both) but not when mixed with pectin. Phytic acid combined with calcium is a strong iron uptake inhibitor. Pectin slightly decreased iron uptake with or without calcium. Tannic acid showed an unexpected behavior, inducing an increase on iron uptake, despite its low Fe dialyzability.

Topics: Adenocarcinoma; Analysis of Variance; Caco-2 Cells; Calcium; Calcium Chloride; Colonic Neoplasms; Dose-Response Relationship, Drug; Humans; Intestinal Absorption; Iron; Models, Biological; Pectins; Phytic Acid; Tannins

In situ coating of 5-fluorouracil pellets by ethylcellulose and pectin powder mixture (8:3 weight ratio) in capsule at simulated gastrointestinal media provides colon-specific drug release in vitro. This study probes into pharmacodynamic and pharmacokinetic profiles of intra-capsular pellets coated in vivo in rats with reference to their site-specific drug release outcomes. The pellets were prepared by extrusion-spheronization technique. In vitro drug content, drug release, in vivo pharmacokinetics, local colonic drug content, tumor, aberrant crypt foci, systemic hematology and clinical chemistry profiles of coated and uncoated pellets were examined against unprocessed drug. In vivo pellet coating led to reduced drug bioavailability and enhanced drug accumulation at colon (179.13 μg 5-FU/g rat colon content vs 4.66 μg/g of conventional in vitro film-coated pellets at 15 mg/kg dose). The in vivo coated pellets reduced tumor number and size, through reforming tubular epithelium with basement membrane and restricting expression of cancer from adenoma to adenocarcinoma. Unlike uncoated pellets and unprocessed drug, the coated pellets eliminated aberrant crypt foci which represented a putative preneoplastic lesion in colon cancer. They did not inflict additional systemic toxicity. In vivo pellet coating to orally target 5-fluorouracil delivery at cancerous colon is a feasible therapeutic treatment approach.

Topics: Aberrant Crypt Foci; Adenocarcinoma; Adenoma; Administration, Oral; Animals; Antimetabolites, Antineoplastic; Biological Availability; Cellulose; Chemistry, Pharmaceutical; Colonic Neoplasms; Dimethylhydrazines; Drug Delivery Systems; Feasibility Studies; Female; Fluorouracil; Pectins; Powders; Rats, Sprague-Dawley; Solubility; Tablets, Enteric-Coated; Technology, Pharmaceutical; Tumor Burden

A polysaccharide fraction, HBE-III, was successfully purified in a high yield (40.4%) from its crude polysaccharide (HBE-0) which was prepared from pectinase hydrolysates of the peels of the Korean Citrus Hallabong. In experimental lung metastasis studies of Colon 26-M3.1 carcinoma cells, prophylactic administration of HBE-III significantly inhibited lung metastasis in a dose-dependent manner. In an in vitro cytotoxicity analysis, HBE-III (up to 1000 μg/mL) did not affect the growth of Colon 26-M3.1 cells and normal cells. HBE-III enhanced production of IL-6 and IL-12 by murine peritoneal macrophages. In an assay for natural killer (NK) cell activity, HBE-III (1000 μg/mouse, i.v.) significantly augmented NK cytotoxicity against Yac-1 tumor cells. The depletion of NK cells by injection of mouse anti-asialo GM1 serum abolished the inhibitory effect of HBE-III on lung metastasis of Colon 26-M3.1 cells. These data suggest that HBE-III may inhibit tumor metastasis via activation of macrophages and NK cells.

Topics: Animals; Antineoplastic Agents, Phytogenic; Cell Line; Cell Line, Tumor; Citrus; Colon; Colonic Neoplasms; Female; Hydrolysis; Interleukin-12; Interleukin-6; Killer Cells, Natural; Lung; Lung Neoplasms; Mice; Mice, Inbred BALB C; Neoplasm Metastasis; Pectins; Polysaccharides

Many efforts have been made to improve the targeting and potential applications of oral drug delivery systems. In this paper, we have demonstrated and investigated how biopolymer nanocapsules can be used as a novel oral drug delivery system for metal-based drug delivery in colon cancer therapy. In this work, β-lactoglobulin nanocapsules containing oxali-palladium were chosen to be synthesized and investigated for the use in colon cancer therapy. These nanocapsules were fabricated in three different pHs (3, 4.5 and 7) and investigated both in the presence and absence of low methoxyl pectin. The results obtained from these experiments indicated that the soluble and stable β-lactoglobulin nanocapsules which contained oxali-palladium had the ability to be formed at a size smaller than 200 nm when in the presence of low methoxyl pectin and at pH 4.5. The in vitro release data indicated that the maximum release occurs at pH 7.0 and 7.5. There lease mechanism demonstrated an anomalous diffusion with a predominant contribution from erosion. Finally, it can be concluded that the β-LG nanocapsules containing oxali-palladium complexed with low methoxyl pectin can be a very promising candidate for the use in oral drug delivery for colon cancer treatment.

Topics: Administration, Oral; Antineoplastic Agents; Colonic Neoplasms; Drug Carriers; Drug Liberation; Hydrogen-Ion Concentration; Kinetics; Lactoglobulins; Nanocapsules; Palladium; Particle Size; Pectins; Temperature; Thermodynamics

Hyaluronan-cisplatin conjugate nanoparticles (HCNPs) were chosen as colon-targeting drug-delivery carriers due to the observation that a variety of malignant tumors overexpress hyaluronan receptors. HCNPs were prepared by mixing cisplatin with a hyaluronan solution, followed by dialysis to remove trace elements. The cells treated with HCNPs showed significantly lower viability than those treated with cisplatin alone. HCNPs were entrapped in Eudragit S100-coated pectinate/alginate microbeads (PAMs) by using an electrospray method and a polyelectrolyte multilayer-coating technique in aqueous solution. The release profile of HCNPs from Eudragit S100-coated HCNP-PAMs was pH-dependent. The percentage of 24-hour drug release was approximately 25.1% and 39.7% in pH 1.2 and pH 4.5 media, respectively. However, the percentage of drug released quickly rose to 75.6% at pH 7.4. Moreover, the result of an in vivo nephrotoxicity study demonstrated that Eudragit S100-coated HCNP-PAMs treatment could mitigate the nephrotoxicity that resulted from cisplatin. From these results, it can be concluded that Eudragit S100-coated HCNP-PAMs are promising carriers for colon-specific drug delivery.

Topics: Alginates; Animals; Body Weight; Cell Survival; Cisplatin; Colonic Neoplasms; Glucuronic Acid; HCT116 Cells; Hexuronic Acids; Humans; Hyaluronic Acid; Male; Microspheres; Nanoconjugates; Pectins; Polymethacrylic Acids; Rats; Rats, Wistar

Pectin is an important dietary component of all fruits and vegetables. Some pectins have been shown to inhibit cancer cell growth, but the effective structures and mechanisms have remained unclear. In this study, we investigated the effects of four structurally distinct pectins on human colon cancer HT-29 cells and the possible mechanisms accounting for the actions. The proliferation inhibitory effect was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Flow cytometry was used to visualize the cell cycle distribution. An reverse transcription polymerase chain reaction (RT-PCR)-based assay was utilized to detect mRNA levels of the proteins related to cell cycle arrest. The data showed that the rhamnogalacturonan I domain-rich pectin from potato inhibited the proliferation of HT-29 cells and induced significant G2/M cell cycle arrest. This inhibitory effect was due to the down-regulation of cyclin B1 and cyclin-dependent kinase 1 expression, but not p21(WAF1/CIP1) expression. The results suggested that the rhamnogalacturonan I domain might relate to the anticancer activity of pectin.

Topics: Antineoplastic Agents, Phytogenic; Cell Cycle Checkpoints; Cell Cycle Proteins; Cell Proliferation; Colon; Colonic Neoplasms; Down-Regulation; HT29 Cells; Humans; Pectins; Phytotherapy; Plant Preparations; RNA, Messenger; Solanum tuberosum

To study the effects of oxaliplatin combined with low-molecular-weight citrus pectin (LCP) on cell proliferation and apoptosis in human colon carcinoma cell line HT29 in vitro.. Effects of oxaliplatin alone and oxaliplatin combined with LCP on HT29 cells proliferation were determined by MTT. Coefficient of drug interaction (CDI) was calculated. Influence of oxaliplatin alone and oxaliplatin combined with LCP on HT29 cell apoptosis was determined by fluorescence activated cell sorting (FACS). Protein expression change of procaspase-3, 8, 9, PARP was examined by Western blotting.. Both oxaliplatin alone and oxaliplatin combined with LCP could suppress HT29 cell proliferation in both dose- and time-dependent manner. The inhibitory effect of oxaliplatin combined with LCP on HT29 cell proliferation was more significant (P<0.01) with a CDI less than 1. FACS analysis showed that oxaliplatin alone and combination therapy could increase the apoptosis proportion of HT29 cells. After the drug treatment for 6, 24, and 48 hours, the apoptosis rate of oxaliplatin alone group was (9.76±0.47)%, (20.45±0.74)%, (28.70±3.29)%, and apoptotic rate of the combination group was (20.63±0.69)%, (34.35±1.02)%, (49.47±3.04)%, respectively, which was significantly higher as compared to oxaliplatin alone (P<0.01). Both oxaliplatin alone and combination therapy down-regulated expressions of procaspase-3, 9, and PARP protein. Procaspase-3, 9, PARP protein expression in combination group decreased more significantly, while procaspase-8 expression was not significantly different between the two groups.. LCP can enhance the ability of oxaliplatin to inhibit cell proliferation and induce apoptosis, which may be associated with the activation of mitochondrial apoptosis pathway.

Topics: Apoptosis; Cell Proliferation; Colonic Neoplasms; HT29 Cells; Humans; Organoplatinum Compounds; Oxaliplatin; Pectins

We have demonstrated that diets containing fish oil and pectin (FO/P) reduce colon tumor incidence relative to control (corn oil and cellulose [CO/C]) in part by inducing apoptosis of DNA-damaged colon cells. Relative to FO/P, CO/C promotes colonocyte expression of the antiapoptotic modulator, Bcl-2, and Bcl-2 promoter methylation is altered in colon cancer. To determine if FO/P, compared with CO/C, limits Bcl-2 expression by enhancing promoter methylation in colon tumors, we examined Bcl-2 promoter methylation, mRNA levels, colonocyte apoptosis and colon tumor incidence in azoxymethane (AOM)-injected rats. Rats were provided diets containing FO/P or CO/C, and were terminated 16 and 34 weeks after AOM injection. DNA isolated from paraformaldehyde-fixed colon tumors and uninvolved tissue was bisulfite modified and amplified by quantitative reverese transcriptase-polymerase chain reaction to assess DNA methylation in Bcl-2 cytosine-guanosine islands. FO/P increased Bcl-2 promoter methylation (P = 0.009) in tumor tissues and colonocyte apoptosis (P = 0.020) relative to CO/C. An inverse correlation between Bcl-2 DNA methylation and Bcl-2 mRNA levels was observed in the tumors. We conclude that dietary FO/P promotes apoptosis in part by enhancing Bcl-2 promoter methylation. These Bcl-2 promoter methylation responses, measured in vivo, contribute to our understanding of the mechanisms involved in chemoprevention of colon cancer by diets containing FO/P.

Topics: Animals; Apoptosis; Azo Compounds; Colonic Neoplasms; Diet; DNA Methylation; DNA, Neoplasm; Fish Oils; Gene Expression Regulation, Neoplastic; Male; Neoplasms, Experimental; Pectins; Promoter Regions, Genetic; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; RNA, Messenger; RNA, Neoplasm

We have demonstrated that fish oil- and pectin-containing (FO/P) diets protect against colon cancer compared with corn oil and cellulose (CO/C) by upregulating apoptosis and suppressing proliferation. To elucidate the mechanisms whereby FO/P diets induce apoptosis and suppress proliferation during the tumorigenic process, we analyzed the temporal gene expression profiles from exfoliated rat colonocytes. Rats consumed diets containing FO/P or CO/C and were injected with azoxymethane (AOM; 2 times, 15 mg/kg body weight, subcutaneously). Feces collected at initiation (24 h after AOM injection) and at aberrant crypt foci (ACF) (7 wk postinjection) and tumor (28 wk postinjection) stages of colon cancer were used for poly (A)+ RNA extraction. Gene expression signatures were determined using Codelink arrays. Changes in phenotypes (ACF, apoptosis, proliferation, and tumor incidence) were measured to establish the regulatory controls contributing to the chemoprotective effects of FO/P. At initiation, FO/P downregulated the expression of 3 genes involved with cell adhesion and enhanced apoptosis compared with CO/C. At the ACF stage, the expression of genes involved in cell cycle regulation was modulated by FO/P and the zone of proliferation was reduced in FO/P rats compared with CO/C rats. FO/P also increased apoptosis and the expression of genes that promote apoptosis at the tumor endpoint compared with CO/C. We conclude that the effects of chemotherapeutic diets on epithelial cell gene expression can be monitored noninvasively throughout the tumorigenic process and that a FO/P diet is chemoprotective in part due to its ability to affect expression of genes involved in apoptosis and cell cycle regulation throughout all stages of tumorigenesis.

Topics: Animals; Azoxymethane; Cell Cycle; Cell Proliferation; Colonic Neoplasms; Diet; Dietary Fats, Unsaturated; Dietary Sucrose; Enterocytes; Feces; Fish Oils; Gene Expression Profiling; Male; Oligonucleotide Array Sequence Analysis; Pectins; Rats; Rats, Sprague-Dawley; RNA, Messenger

Currently, colon-specific drug delivery systems have been investigated for drugs that can exert their bioactivities in the colon. In this study, Eudragit® S100 coated calcium pectinate microsphere, a pH-dependent and enzyme-dependent system, as colon-specific delivery carrier for curcumin was investigated. Curcumin-loaded calcium pectinate microspheres were prepared by emulsification-linkage method, and the preparation technology was optimised by uniform experimental design. The morphology of microspheres was observed under scanning electron microscopy. Interactions between drug and polymers were investigated with differential scanning calorimetry (DSC) and X-ray diffraction. In vitro drug release studies were performed in simulated colonic fluid in the presence of Pectinex Ultra SP-L or 1% (w/v) rat caecal content, and the results indicated that the release of curcumin was significantly increased in the presence of 1% (w/v) rat caecal contents. It could be concluded that Eudragit® S100 coated calcium pectinate microsphere was a potential carrier for colon delivery of curcumin.

Topics: Animals; Antineoplastic Agents; Calorimetry, Differential Scanning; Cecum; Coated Materials, Biocompatible; Colon; Colonic Neoplasms; Curcumin; Drug Delivery Systems; Microscopy, Electron, Scanning; Microspheres; Pectins; Polymethacrylic Acids; Rats; X-Ray Diffraction

We have hypothesized that dietary modulation of intestinal non-coding RNA [microRNA (miRNA)] expression may contribute to the chemoprotective effects of nutritional bioactives (fish oil and pectin). To fully understand the effects of these agents on the expression of miRNAs, Sprague-Dawley rats were fed diets containing corn oil or fish oil with pectin or cellulose and injected with azoxymethane (AOM, a colon-specific carcinogen) or saline (control). Real-time polymerase chain reaction using miRNA-specific primers and Taq Man probes was carried out to quantify effects on miRNA expression in colonic mucosa. From 368 mature miRNAs assayed, at an early stage of cancer progression (10 week post AOM injection), let-7d, miR-15b, miR-107, miR-191 and miR-324-5p were significantly (P < 0.05) affected by diet x carcinogen interactions. Overall, fish oil fed animals exhibited the smallest number of differentially expressed miRNAs (AOM versus saline treatment). With respect to the tumor stage (34 week post AOM injection), 46 miRNAs were dysregulated in adenocarcinomas compared with normal mucosa from saline-injected animals. Of the 27 miRNAs expressed at higher (P < 0.05) levels in tumors, miR-34a, 132, 223 and 224 were overexpressed at >10-fold. In contrast, the expression levels of miR-192, 194, 215 and 375 were dramatically reduced (< or = 0.32-fold) in adenocarcinomas. These results demonstrate for the first time the utility of the rat AOM model and the novel role of fish oil in protecting the colon from carcinogen-induced miRNA dysregulation.

Topics: Adenocarcinoma; Animals; Azoxymethane; Carcinogens; Colon; Colonic Neoplasms; Epigenesis, Genetic; Fatty Acids, Unsaturated; Fish Oils; Gene Expression Profiling; Male; MicroRNAs; Pectins; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction

To observe the expression of galectin-3 in the liver metastasis of colon cancer in mice and the inhibitory effect of modified citrus pectin (MCP) on galectin-3 expression.. Seventy-five Balb/c mice were randomized into 5 groups, namely the negative control, positive control, low-concentration MCP, moderate-concentration MCP and high-concentration MCP groups. CT26 colon cancer cells were injected into the subcapsule of the mouse spleen to establish liver metastasis models of colon cancer, but the mice in the negative control group received no tumor cell injection. MCP was added into the drinking water of the mice at the concentrations of 0, 1.0%, 2.5% and 5.0% (m/V). The liver metastasis was observed 3 weeks after tumor cell inoculation. Enzyme-linked immunosorbent assay was performed to determine the serum galectin-3 level. A tissue microarray of the liver metastasis was prepared for immunohistochemical detection of galectin-3 expression in the liver metastasis.. In the positive control, low-, moderate- and high-concentration MCP groups, the rates of liver metastasis were 100%, 80%, 73.3% and 60%, respectively. The number of liver metastases in high-concentration MCP group was significantly smaller than that in the positive control group (P<0.05). In the 4 groups with tumor cell inoculation, the median volume of the primary lesions in the spleen was 1.51, 0.93, 0.77 and 0.70 cm(3), respectively, which were significantly smaller in the moderate- and high-concentration MCP groups than in the positive control group (P<0.05). The serum galectin-3 level in the positive control group and MCP-treated groups were significantly higher than that in the negative control group (P<0.01), but similar between the positive control group and the MCP-treated groups (P>0.05). In the positive control and the MCP-treated groups, the expression of galectin-3 in the liver metastases showed no significant differences (P>0.05).. The expression of galetin-3 is significantly increased in the liver metastasis of colon cancer, and MCP can effectively inhibit the liver metastasis.

Topics: Animals; Cell Line, Tumor; Citrus; Colonic Neoplasms; Female; Galectin 3; Immunohistochemistry; Liver Neoplasms; Mice; Mice, Inbred BALB C; Pectins; Phytotherapy; Random Allocation

To discuss the expression of glactin-3 in liver metastasis of colon cancer and its inhibition by modified citrus pectin (MCP) in mice.. Seventy-five Balb/c mice were randomly divided into negative control group (n = 15), positive control group (n = 15), low MCP concentration group (n = 15), middle MCP concentration group (n = 15) and high MCP concentration group (n = 15). CT26 colon cancer cells were injected into the subcapsule of mouse spleen in positive control group, low, middle and high MCP concentrations groups, except in negative control, to set up a colon cancer liver metastasis model. The concentration of MCP in drinking water was 0.0%, 0.0%, 1.0%, 2.5% and 5.0% (wt/vol), respectively. Liver metastasis of colon cancer was observed after 3 wk. Enzyme-linked immunosorbent assay (ELISA) was used to detect the concentration of galectin-3 in serum. Expression of galectin-3 in liver metastasis was detected by immunohistochemistry.. Except for the negative group, the percentage of liver metastasis in the other 4 groups was 100%, 80%, 73.3% and 60%, respectively. The number of liver metastases in high MCP concentration group was significantly less than that in positive control group (P = 0.008). Except for the negative group, the median volume of implanted spleen tumor in the other 4 groups was 1.51 cm(3), 0.93 cm(3), 0.77 cm(3) and 0.70 cm(3), respectively. The volume of implanted tumor in middle and high MCP concentration groups was significantly smaller than that in positive control group (P = 0.019; P = 0.003). The concentration of serum galectin-3 in positive control and MCP treatment groups was significantly higher than that in the negative control group. However, there was no significant difference between them. Except for the negative control group, the expression of galectin-3 in liver metastases of the other 4 groups showed no significant difference.. Expression of galetin-3 increases significantly in liver metastasis of colon cancer, which can be effectively inhibited by MCP.

Topics: Animals; Cell Adhesion; Cell Aggregation; Cell Line, Tumor; Citrus; Colonic Neoplasms; Disease Models, Animal; Female; Galectin 3; Liver Neoplasms; Mice; Mice, Inbred BALB C; Pectins; Phytotherapy; Plant Extracts; Splenic Neoplasms

We have shown that dietary fish oil and pectin (FP) protects against radiation-enhanced colon cancer by upregulating apoptosis in colonic mucosa. To investigate the mechanism of action, we provided rats (n = 40) with diets containing the combination of FP or corn oil and cellulose (CC) prior to exposure to 1 Gy, 1 GeV/nucleon Fe-ion. All rats were injected with a colon-specific carcinogen, azoxymethane (AOM; 15 mg/kg), 10 and 17 days after irradiation. Levels of colonocyte apoptosis, prostaglandin E(2) (PGE(2)), PGE(3), microsomal prostaglandin E synthase-2 (mPGES-2), total beta-catenin, nuclear beta-catenin staining (%) and peroxisome proliferator-activated receptor delta (PPARdelta) expression were quantified 31 weeks after the last AOM injection. FP induced a higher (P < 0.01) apoptotic index in both treatment groups, which was associated with suppression (P < 0.05) of antiapoptotic mediators in the cyclooxygenase (COX) pathway (mPGES-2 and PGE(2)) and the Wnt/beta-catenin pathway [total beta-catenin and nuclear beta-catenin staining (%); P < 0.01] compared with the CC diet. Downregulation of COX and Wnt/beta-catenin pathways was associated with a concurrent suppression (P < 0.05) of PPARdelta levels in FP-fed rats. In addition, colonic mucosa from FP animals contained (P < 0.05) a proapoptotic, eicosapentaenoic acid-derived COX metabolite, PGE(3). These results indicate that FP enhances colonocyte apoptosis in AOM-alone and irradiated AOM rats, in part through the suppression of PPARdelta and PGE(2) and elevation of PGE(3). These data suggest that the dietary FP combination may be used as a possible countermeasure to colon carcinogenesis, as apoptosis is enhanced even when colonocytes are exposed to radiation and/or an alkylating agent.

Topics: Alprostadil; Animals; Apoptosis; Colon; Colonic Neoplasms; Dietary Fats; Dinoprostone; Fish Oils; Intestinal Mucosa; Male; Neoplasms, Radiation-Induced; Pectins; PPAR delta; Rats; Rats, Sprague-Dawley

The role of dietary components in cancer progression and metastasis is an emerging field of clinical importance. Many stages of cancer progression involve carbohydrate-mediated recognition processes. We therefore studied the effects of high pH- and temperature-modified citrus pectin (MCP), a nondigestible, water-soluble polysaccharide fiber derived from citrus fruit that specifically inhibits the carbohydrate-binding protein galectin-3, on tumor growth and metastasis in vivo and on galectin-3-mediated functions in vitro.. In vivo tumor growth, angiogenesis, and metastasis were studied in athymic mice that had been fed with MCP in their drinking water and then injected orthotopically with human breast carcinoma cells (MDA-MB-435) into the mammary fat pad region or with human colon carcinoma cells (LSLiM6) into the cecum. Galectin-3-mediated functions during tumor angiogenesis in vitro were studied by assessing the effect of MCP on capillary tube formation by human umbilical vein endothelial cells (HUVECs) in Matrigel. The effects of MCP on galectin-3-induced HUVEC chemotaxis and on HUVEC binding to MDA-MB-435 cells in vitro were studied using Boyden chamber and labeling assays, respectively. The data were analyzed by two-sided Student's t test or Fisher's protected least-significant-difference test.. Tumor growth, angiogenesis, and spontaneous metastasis in vivo were statistically significantly reduced in mice fed MCP. In vitro, MCP inhibited HUVEC morphogenesis (capillary tube formation) in a dose-dependent manner. In vitro, MCP inhibited the binding of galectin-3 to HUVECs: At concentrations of 0.1% and 0.25%, MCP inhibited the binding of galectin-3 (10 micro g/mL) to HUVECs by 72.1% (P =.038) and 95.8% (P =.025), respectively, and at a concentration of 0.25% it inhibited the binding of galectin-3 (1 micro g/mL) to HUVECs by 100% (P =.032). MCP blocked chemotaxis of HUVECs toward galectin-3 in a dose-dependent manner, reducing it by 68% at 0.005% (P<.001) and inhibiting it completely at 0.1% (P<.001). Finally, MCP also inhibited adhesion of MDA-MB-435 cells, which express galectin-3, to HUVECs in a dose-dependent manner.. MCP, given orally, inhibits carbohydrate-mediated tumor growth, angiogenesis, and metastasis in vivo, presumably via its effects on galectin-3 function. These data stress the importance of dietary carbohydrate compounds as agents for the prevention and/or treatment of cancer.

Topics: Adenocarcinoma; Administration, Oral; Animals; Antineoplastic Agents, Phytogenic; Blotting, Western; Breast Neoplasms; Chemotaxis; Citrus; Colonic Neoplasms; Disease Progression; Dose-Response Relationship, Drug; Endothelium, Vascular; Fluorescent Antibody Technique, Indirect; Galectin 3; Immunohistochemistry; Mice; Mice, Nude; Neoplasm Metastasis; Neoplasm Transplantation; Neoplasms; Neovascularization, Pathologic; Pectins; Recombinant Proteins; Tumor Cells, Cultured; Umbilical Veins

The number of colorectal tumors per mouse induced by 1,2-dimethylhydrazine in transgenic (Tg) mice carrying human c-Ha-ras genes was significantly reduced by ingestion of apple pectin (AP) or a culture condensate of Bifidobacterium longum(MB) compared with a control diet and non-Tg mice. However, there were no differences in the composition of fecal flora, water content, beta-glucuronidase and beta-glucosidase activities, and concentrations of organic acids and putrefactive products in the feces between the AP or MB diet and the control diet, or between the Tg mice and non-Tg mice. The concentration of secondary bile acids in the MB diet group was higher than that in the control group. These results suggested that there was no relationship between prevention of colorectal tumors in Tg mice and the AP or MB diet, or improvement of the intestinal environment due to these functional foods.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; beta-Glucosidase; Bifidobacterium; Colonic Neoplasms; Colorectal Neoplasms; Feces; Female; Fruit; Genes, ras; Glucuronidase; Humans; Male; Mice; Mice, Inbred Strains; Mice, Transgenic; Pectins; Rectal Neoplasms

We have recently demonstrated that overexpression of PKC beta(II) renders transgenic mice more susceptible to carcinogen-induced colonic hyperproliferation and aberrant crypt foci formation. In order to further investigate the ability of PKC beta(II) to modulate colonocyte cytokinetics, we determined the localization of PKC beta(II) with respect to cell proliferation and apoptosis along the entire colonic crypt axis following carcinogen and diet manipulation. Rats were provided diets containing either corn oil [containing n-6 polyunsaturated fatty acids (PUFA)] or fish oil (containing n-3 PUFA), cellulose (non-fermentable fiber) or pectin (fermentable fiber) and injected with azoxymethane (AOM) or saline. After 16 weeks, an intermediate time point when no macroscopic tumors are detected, colonic sections were utilized for immunohistochemical image analysis and immunoblotting. Cell proliferation was measured by incorporation of bromodeoxyuridine into DNA and apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling. In the distal colon, PKC beta(II) staining was localized to the upper portion of the crypt. In comparison, proximal crypts had more (P < 0.05) staining in the lower tertile. AOM enhanced (P < 0.05) PKC beta(II) expression in all regions of the distal colonic crypt (upper, middle and lower tertiles). There was also an interaction (P < 0.05) between dietary fat and fiber on PKC beta(II) expression (corn/pectin > fish/cellulose, fish/pectin > corn/cellulose) in all regions of the distal colonic crypt. With respect to colonic cell kinetics, proliferation paralleled the increase in PKC beta(II) expression in carcinogen-treated animals. In contrast, apoptosis at the lumenal surface was inversely proportional to PKC beta(II) expression in the upper tertile. These results suggest that an elevation in PKC beta(II) expression along the crypt axis in the distal colon is linked to enhancement of cell proliferation and suppression of apoptosis, predictive intermediate biomarkers of tumor development. Therefore, select dietary factors may confer protection against colon carcinogenesis in part by blocking carcinogen-induced PKC beta(II) expression.

Topics: Animals; Apoptosis; Azoxymethane; Carcinogens; Cell Cycle; Cell Division; Cellulose; Colon; Colonic Neoplasms; Corn Oil; Diet; Fatty Acids, Omega-3; Immunohistochemistry; Isoenzymes; Male; Pectins; Precancerous Conditions; Protein Kinase C; Protein Kinase C beta; Rats; Rats, Sprague-Dawley; Subcellular Fractions

The colonic crypt contains highly proliferative cells in its base and differentiated cells on its luminal surface. Carcinogenesis significantly affects this orderly cellular distribution. The aims of this study were: i) to examine the expression of apoptosis-related proteins along the crypt-lumen axis during 1, 2-dimethylhydrazine (DMH)-induced carcinogenesis, ii) to assess whether a diet supplemented with the soluble fiber pectin affects those parameters, in comparison to non-carcinogen-treated rats and in relation to rats fed a standard diet and treated with DMH. The pectin-enriched diet induced upregulation of active caspase-1 subunit (20 kDa) and of caspase-3 precursor in DMH-treated rats. Pectin enhanced caspase-3 activity in all colonocyte populations, in both non-DMH and DMH-treated rats. The luminal colonocytes exhibited higher caspase-3 activity than proliferative colonocytes of rats fed a standard diet in non-DMH and DMH-treated rats, whereas in pectin-fed non-DMH-treated rats, equal activity was measured among all colonocyte populations. In the DMH-treated rats, the cleaved poly(ADP-ribose) polymerase subunit (89 kDa) was detected in luminal colonocytes of rats fed pectin and was higher than in rats fed the standard diet. Bak was equally expressed in isolated colonocytes from rats of both dietary groups treated with DMH and in the normal rats fed pectin, whereas in the non-DMH-treated rats fed a standard diet, higher expression was obtained in differentiated colonocytes. In the DMH-treated rats, Bcl-2 expression was lower in all colonocytes harvested from rats fed pectin, relative to rats fed the standard diet. Apoptotic index in the DMH-treated groups was higher in rats receiving the pectin diet compared with the standard diet in both the differentiated cell populations and the proliferating colonocytes. Average tumor number and volume per rat were lower in rats fed pectin. These findings indicate that dietary fibers regulate expression, function and distribution of apoptotic-related proteins in the crypt during colon carcinogenesis, changes that probably induce a reduction in tumor volume. We assume that butyrate, produced following fermentation of pectin, may play a key role in these effects.

Topics: 1,2-Dimethylhydrazine; Animals; Apoptosis; bcl-2 Homologous Antagonist-Killer Protein; Blotting, Western; Carcinogens; Caspase 1; Caspase 3; Caspases; Colonic Neoplasms; Dietary Carbohydrates; Energy Intake; Male; Membrane Proteins; Pectins; Poly(ADP-ribose) Polymerases; Proteins; Proto-Oncogene Proteins c-bcl-2; Rats

The present study was aimed at evaluating the effect of high intracolonic butyrate concentrations, either through fermentation of a soluble fiber-enriched diet or via intracolonic butyrate instillation, on colon cancer in a chemically induced (dimethylhydrazine) rat model. The effects were tested in four groups of dimethylhydrazine-treated rats: (i) rats fed a standard diet, (ii) rats fed a diet enriched with 15% citrus pectin, a soluble fiber that ferments and produces a high concentration of intracolonic butyrate, (iii) rats fed a standard diet and intrarectally instilled with a sodium butyrate solution (50 mM), (iv) rats fed a standard diet and intrarectally instilled with sodium butyrate vehicle solution (100 mM NaCl). The apoptotic index in the distal colon of rats fed pectin was higher than in colonic tissue from rats fed a standard diet. The expression of caspase-1, a cysteine protease implicated in the regulation of programmed cell death, as detected by both Northern and Western analysis, showed the highest mRNA and protein levels in colonic tissue from rats intrarectally instilled with butyrate. Immunohistology confirmed the Western blot findings. Expression of the cleaved poly(ADP-ribose) polymerase product, a downstream nuclear substrate for caspase-3 in the apoptotic pathway, was elevated in both the pectin-fed and butyrate-instilled groups. Expression of the antiapoptotic protein Bcl-2 was significantly reduced following pectin feeding as well as butyrate instillation. The highest expression of Bcl-2 was observed in tumor tissue. A marked reduction in aberrant crypt number was observed in colonic tissue obtained from both the pectin-fed and butyrate-instilled groups relative to rats from the standard diet group. The average tumor volume per rat in both the pectin-fed and butyrate-instilled groups was significantly lower than in rats from the standard diet and the sodium butyrate vehicle-instilled groups. We conclude that high butyrate levels, either instilled or obtained following fermentation of soluble dietary fibers, inhibit early and late events in colon tumorigenesis by controlling the transcription expression and activity of key proteins involved in the apoptotic cascade.

Topics: 1,2-Dimethylhydrazine; Animals; Apoptosis; Blotting, Northern; Blotting, Western; Body Weight; Butyrates; Caspase 1; Colon; Colonic Neoplasms; Diet; Immunohistochemistry; In Situ Nick-End Labeling; Isobutyrates; Male; Models, Biological; Mutagens; Neoplasms; Pectins; Poly(ADP-ribose) Polymerases; Rats; RNA, Messenger; Time Factors

The health benefits of fruits and vegetables have been the subject of numerous investigations over many years. Two natural substances, quercetin (a flavonoid) and citrus pectin (a polysaccharide found in the cell wall of plants) are of particular interest to cancer researchers. Two modified versions of these substances - quercetin chalcone (QC) and a pH-modified citrus pectin (MCP) - are the focus of this study. Previous research has confirmed that quercetin exhibits antitumor properties, likely due to immune stimulation, free radical scavenging, alteration of the mitotic cycle in tumor cells, gene expression modification, anti-angiogenesis activity, or apoptosis induction, or a combination of these effects. MCP has inhibited metastases in animal studies of prostate cancer and melanoma. To date, no study has demonstrated a reduction in solid tumor growth with MCP, and there is no research into the antitumor effect of QC. This study examines the effects of MCP and QC on the size and weight of colon-25 tumors implanted in balb-c mice. Fifty mice were orally administered either 1 ml distilled water (controls), low-dose QC (0.8 mg/ml), high-dose QC (1.6 mg/ml), low-dose MCP (0. 8 mg/ml) or high-dose MCP (1.6 mg/ml) on a daily basis, beginning the first day of tumor palpation (usually eight days post-implantation). A significant reduction in tumor size was noted at day 20 in all groups compared to controls. The groups given low-dose QC and MCP had a 29-percent (NS) and 38-percent (p<0.02) decrease in size, respectively. The high-dose groups had an even more impressive reduction in size; 65 percent in the QC group and 70 percent in the mice given MCP (both p<0.001). This is the first evidence that MCP can reduce the growth of solid primary tumors, and the first research showing QC has antitumor activity. Additional research on these substances and their effect on human cancers is warranted.

Topics: Administration, Oral; Animals; Citrus; Colonic Neoplasms; Female; Male; Mice; Mice, Inbred BALB C; Neoplasm Transplantation; Pectins; Phytotherapy; Quercetin

Short chain fatty acids (SCFA) are considered to be beneficial fermentation products in the gut by exerting trophic effects in non-transformed colon cells and by slowing proliferation and enhancing differentiation in colonic tumour cells. We have studied the further effects of SCFA on cellular events of early carcinogenesis, genotoxicity and cytotoxicity in rat distal colon cells. Cytotoxicity was assessed by measuring trypan blue exclusion and by determining the H2O2-induced changes in intracellular calcium concentration ([Ca2+]i) using a fluorospectrophotometer and the calcium-sensitive fluorescent dye Fura-2. The microgel electrophoresis technique (COMET assay) was used to assess oxidative DNA damage. Individual SCFA and physiological SCFA mixtures were investigated for their potential to prevent DNA and cell damage induced by H2O2. For this, freshly isolated colon cells were treated with H2O2 (100-500 microM) and 6.25 mM SCFA. We have found 100-500 microM H2O2 to cause a fast initial increase in [Ca2+]i, whereafter the levels gradually further increased. Addition of SCFA did not affect [Ca2+]i nor did it reduce the H2O2-induced increase in [Ca2+]i. Butyrate and acetate were able to reduce the induction of DNA damage by 100, 200 and 500 microM H2O2, respectively. In contrast, i-butyrate and propionate were ineffective. The degree of reduction of DNA damage for the two protective SCFA was similar. Physiological mixtures containing acetate, propionate and butyrate in ratios of 41:21:38 or 75:15:10 that are expected to arise in the colon after fermentation of resistant starches and pectin, respectively, did not show significant antigenotoxic effects. The major difference between butyrate and acetate, on one hand, and i-butyrate and propionate, on the other hand, is that the former compounds are utilized best as energy sources by the colon cells. Therefore, our results on antigenotoxicity coupled with the findings on [Ca2+]i homeostasis indicate that molecular effects on the energy system render these non-transformed, freshly isolated colon cells to be less susceptible to H2O2.

Topics: Acetates; Animals; Butyrates; Calcimycin; Calcium; Cell Differentiation; Cell Division; Cells, Cultured; Colon; Colonic Neoplasms; Dietary Carbohydrates; Dietary Fiber; DNA Damage; Energy Metabolism; Fatty Acids; Fermentation; Hydrogen Peroxide; Ionophores; Oxidation-Reduction; Oxidative Stress; Pectins; Propionates; Rats; Starch

Alterations in ATP production, intracellular energy levels and mitochondrial function have been shown to trigger cytokinetic events in vitro, including inhibition of cell division, abnormal or blocked differentiation and inhibition of apoptosis. Changes in colonic cytokinetics are directly related to colon tumorigenesis but alterations in energy metabolism during the tumorigenic process have never been reported. We conducted a 2 x 2 x 3 factorial design study in 120 male Sprague-Dawley rats with two diets (pectin or cellulose-supplemented), two injected subgroups (with or without the carcinogen azoxymethane, AOM) and three termination time points (6, 16 and 36 wk post-second injection). Colonocytes were isolated and incubated with their primary energy substrates (radiolabeled butyrate, glucose, glutamine and beta-hydroxybutyrate) for 60 min. Production of lactate, ketone bodies and CO2 were determined. At 6 wk, there were no significant differences in metabolism among treatments. In contrast, at 16 wk, AOM-injected rats had dramatically lower rates of CO2 production (P < 0.001) from both glucose and butyrate and lower rates of lactate and ketone body production than their saline counterparts. At 36 wk, when tumors developed, the depressed production of lactate and ketone bodies seen in AOM-injected rats at 16 wk returned to control values. However, in AOM-injected rats, CO2 production from glucose and butyrate remained depressed. Cellulose feeding resulted in decreased oxidation of glucose, butyrate and glutamine and an increased production of ketone bodies from butyrate by colonocytes compared with pectin feeding at 36 wk. We conclude that colonocyte energy metabolism differs in AOM-injected rats vs. saline controls and changes during tumorigenesis, and suggest a relationship between intracellular energy status and changes in cell kinetics. This is the first report that such a relationship may exist in vivo.

Topics: 3-Hydroxybutyric Acid; Animals; Azoxymethane; Butyrates; Butyric Acid; Carcinogens; Cellulose; Colon; Colonic Neoplasms; Diet; Energy Metabolism; Glucose; Glutamine; Hydroxybutyrates; Ketone Bodies; Kinetics; Lactic Acid; Male; Oxidation-Reduction; Pectins; Rats; Rats, Sprague-Dawley

An analysis of viable bacterial populations enumerated on carbohydrate selective media was used to simulate the colonic environment in vitro and determine if differential media could detect significant microbial shifts due to dietary fiber source, dietary fat source, and carcinogen. Male Sprague-Dawley rats were provided with either pectin or cellulose as a fiber source, either corn or fish oil as a source of fatty acids, and injected with either azoxymethane (AOM), a gastrointestinal carcinogen, or saline in a 2 x 2 x 2 factorial design. At 6 and 10 mo of age, fresh feces were collected, homogenized in anaerobic buffer and anaerobically plated onto differential media. Diets containing pectin supported more anaerobes at 6 mo of age (P < 0.01) than diets containing cellulose. Rats injected with AOM and consuming either pectin or corn oil supported more anaerobes at 10 mo of age (P < 0.05) than rats injected with saline and consuming the same diets. Rats consuming cellulose and receiving AOM but not expressing tumors possessed larger anaerobic populations at 10 mo of age (P < 0.05) than rats consuming cellulose, injected with AOM and expressing tumors. These effects show that gastrointestinal bacterial populations, as measured by carbohydrate specific media, respond to dietary changes such as dietary fiber source, and thus may play a key role in the etiology of colon cancer.

Topics: Aging; Animals; Anti-Infective Agents, Local; Azoxymethane; Bacteria; Carcinogens; Cellulose; Cetrimonium; Cetrimonium Compounds; Colon; Colonic Neoplasms; Colony Count, Microbial; Coloring Agents; Congo Red; Corn Oil; Culture Media; Dietary Fats; Dietary Fiber; Feces; Fish Oils; Male; Pectins; Rats; Rats, Sprague-Dawley

Pectin is a partially methoxylated polymer of galacturonic acid obtained from fruits. Among pectin, apple pectin exerts stronger bacteriostatical action on Staphylococcus aureus, Streptococcus faecalis, Pseudomonas aeruginosa and Escherichia coli in comparison with citrus pectin. In this study, we used water-soluble methoxylated pectin from apple. The diet, supplemented by 20% apple pectin, significantly decreased the number of tumors and the incidence of colon tumor. PGE2 level in distal colonic mucosa in 20% apple pectin fed rats were lower than those in basal diet fed rats. Fecal beta-glucuronidase activities in the apple pectin fed group, which has been considered a key enzyme for the final activation of Dimethylhydrazine metabolism to carcinogens in the colonic lumen, were signifieantly lower than those in control group at initiation stage of carcinogenesis. In the case the concentrations of beta-glueosidase and azoreductase were also decreased. The effect of apple pectin on the colon carcinogenesis may partially depend on PGE, concentration decrease in colonic mucosa and on the type of pectin, also related to fecal enzyme activities.

Topics: Animals; Anticarcinogenic Agents; Citrus; Colonic Neoplasms; Dinoprostone; Drug Screening Assays, Antitumor; Feces; Fruit; Glucuronidase; Male; NADH, NADPH Oxidoreductases; Neoplasms, Experimental; Nitroreductases; Pectins; Rats; Tryptophanase

Because of the potential significance of colonic bacteria in colon carcinogenesis, we investigated the effect of pectin of different types on fecal bacterial enzymes (beta-glucuronidase, beta-glucosidase and tryptophanase) at various periods of time after feeding rats with pectin-containing diets during azoxymethane-induced colon carcinogenesis. The diet supplemented with 20% apple pectin or 20% citrus pectin decreased the multiplicity of colon tumors, and the number of tumors was significantly decreased in the group fed apple pectin. The incidence of colon tumors in the apple pectin group was lower than that in the control group. The mean tumor size was similar among the three groups. Apple pectin feeding decreased fecal beta-glucosidase and tryptophanase levels. Furthermore, a significant decrease in the activity of beta-glucuronidase was observed in the apple pectin group during the initiation phase. These findings suggest that the protective effect of pectin on colon carcinogenesis may be dependent on the type of pectin and be related to the decrease of beta-glucuronidase activity in the initiation stage of carcinogenesis.

Topics: Adenocarcinoma; Animals; Azoxymethane; beta-Glucosidase; Body Weight; Carcinoma, Signet Ring Cell; Colonic Neoplasms; Feces; Fruit; Glucuronidase; Male; Pectins; Rats; Tryptophanase

The effects of specific dietary interventions on incidence of carcinogen-induced cancer and on cryptal cell proliferation in areas of the colon located either over aggregates of lymphoid nodules (ALN) or away from ALN was investigated. Groups of dimethylhydrazine (DMH) treated rats or non-DMH-treated rats were fed a basal AIN-76 diet less fiber of any type, or the basal fiber free diet supplemented with 10% pectin and with 5%, 10%, or 20% corn oil. The adenocarcinoma (AC) incidence was determined in regions of the colon, i.e. ascending, descending, descending over the ALN and descending away from the ALN. The results indicate that: (i) factors associated with ALN promote AC formation, (ii) dietary modifications (addition of pectin and of 20% corn oil to the diet) each cause significant site specific suppression of AC incidence, (iii) DMH-treatment rendered crypts non-responsive to the suppression of cryptal cell proliferation which occurred in the rats not treated with DMH (suggestive of a DMH-induced loss in the regulation of cell proliferation) and (iv) reduction of AC incidence was not always accompanied by reduction in crypt cell proliferation. Studies of intervention procedures designed to prevent colon cancer should take into account the colon site specific tumorigenic response to the preventive agent and should not rely on a single biomarker to predict the efficacy of the intervention.

Topics: Animals; Body Weight; Cell Division; Colonic Neoplasms; Corn Oil; Diet; Intestinal Mucosa; Male; Pectins; Rats; Rats, Sprague-Dawley

The effect of dietary supplementation with pectin and/or guar gum on 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis was studied using 120 male Sprague-Dawley rats. The rats were given a weekly injection of DMH for 8 weeks and were maintained on a basal fiber-free diet supplemented with 5% cellulose. The rats were then subdivided into four groups and kept on the basal fiber-free diet supplemented with either no fiber, 10% pectin, 10% guar gum or a combination of 5% pectin/5% guar gum for a period of 24 weeks. The 8 weeks of DMH administration were defined as the initiation stage of carcinogenesis and the next 24 weeks were defined as the promotional stage of carcinogenesis. Food and water were available ad libitum. The rats were killed 32 weeks after the start of the experiment and tumor incidence, location and frequency in the colon were determined. Other parameters measured were body weight and caloric intake. Dietary fiber supplementation with 10% pectin or with 10% guar gum but not with the combination of 5% pectin/5% guar gum (fed during the promotional stage of carcinogenesis), was found to suppress colon cancer incidence to a significant extent.

Topics: 1,2-Dimethylhydrazine; Adenocarcinoma; Animals; Carcinogens; Colonic Neoplasms; Dietary Fiber; Dimethylhydrazines; Energy Intake; Galactans; Male; Mannans; Pectins; Plant Gums; Rats; Rats, Inbred Strains

Seven-week-old Sprague-Dawley rats were fed a semipurified AIN76 diet and were given a weekly injection of the colon carcinogen 1,2-dimethylhydrazine for 8 weeks (initiation stage of carcinogenesis). The rats were divided into seven groups and each group of rats was placed on one of seven different modifications of the AIN76 diet for the next 24 weeks (promotional stage of carcinogenesis). The mean numbers of aberrant crypt foci/rat and the incidence of adenocarcinomas from some of the seven dietary groups were found to be significantly different. However, all attempts to show a significant correlation between the mean number of aberrant crypt foci/rat and the incidence of adenocarcinomas failed. Therefore, the number of aberrant crypt foci/rat cannot by itself be used as a reliable quantitative predictor (biomarker) of the efficacy of dietary intervention or of chemopreventive procedures on modulating the risk of developing colon cancer. This conclusion emphasizes the need for end point validation of potential cancer biomarkers before the biomarkers can be considered predictive of modulation of the risk for colon cancer.

Topics: Adenocarcinoma; Analysis of Variance; Animals; Colon; Colonic Neoplasms; Corn Oil; Diet; Dimethylhydrazines; Male; Pectins; Prognosis; Rats; Rats, Inbred Strains; Regression Analysis

The comparative effects of different fibers on colonic luminal pH, crypt cell proliferation, and colon carcinogenesis were studied in 120 male Sprague-Dawley rats. The animals were divided into five equal groups and fed either a basal fiber free diet or the basal diet supplemented with 10% pectin, cellulose or guar, or 20% oat bran for up to 30 weeks. 1,2-Dimethylhydrazine was given at 20 mg/kg body weight as a weekly s.c. injection for 12 weeks. Food intake and weight gain were similar in all diet groups. At sacrifice, in vivo pH measurements showed that compared to fiber free rats, all fibers significantly acidified large bowel luminal contents (P less than 0.05). In the guar group 62.5% of rats developed colonic tumors compared to 33.4% of the fiber free rats (P less than 0.05). The yield of proximal colonic adenocarcinomas in the oat bran, pectin, and guar groups was increased by 4.5 to 5 times over the fiber free level (P less than 0.05-0.025). Pectin and guar provided the greatest stimulus to cell proliferation. A lower luminal pH was associated with a higher tumor yield and increased epithelial cell proliferation. Thus, acidification of colonic contents by high fiber diets failed to inhibit rat colon carcinogenesis, while the consumption of soluble fibers, such as oat bran, pectin, and guar, was associated with enhancement of proximal colon carcinogenesis.

Topics: 1,2-Dimethylhydrazine; Adenocarcinoma; Animals; Cell Division; Cellulose; Colon; Colonic Neoplasms; Dietary Fiber; Dimethylhydrazines; Feces; Galactans; Hydrogen-Ion Concentration; Male; Mannans; Pectins; Plant Gums; Rats; Rats, Inbred Strains

The fecal microflora enzymes, beta-glucuronidase and beta-glucosidase, as well as fecal bacterial counts, were examined during colon carcinogenesis in rats administered parenteral 1,2-dimethylhydrazine and fed nutritionally equivalent diets free of fiber or containing one of three single sources of dietary fiber (cellulose, hemicellulose, and pectin). Whereas pectin-fed animals had increased fecal beta-glucuronidase activities, those fed cellulose and hemicellulose, two fibers protective in dimethylhydrazine colon neoplasia, had decreased activities. Although fecal bacterial counts were not significantly changed, similar differential changes in fecal beta-glucosidase activity were noted: cellulose but not pectin or hemicellulose feeding was associated with reduced activity. Although cellulose fiber may cause differing physiological effects resulting in a reduction in colonic neoplasia development in this experimental animal model, decreased bacterial metabolic enzyme activation of carcinogens or cocarcinogens may lead to diminished exposure of colonic cells to exogenous or endogenous mutagens.

Topics: Animals; beta-Glucosidase; Cellulose; Colon; Colonic Neoplasms; Dietary Fiber; Dimethylhydrazines; Feces; Glucosidases; Glucuronidase; Male; Pectins; Rats

The effect of 5% low-methoxylated pectin, high-methoxylated pectin, and guar gum on 1,2-dimethylhydrazine initiation of colon cancer was investigated using groups of 30 rats. The growth of the rats in the different groups was very similar to that of control group fed a fiber-free diet. Both kinds of pectin increased the multiplicity of color tumors, whereas guar gum did not significantly influence carcinogenesis. Bacterial beta-glucuronidase activity in feces and colonic content was the same in pectin-fed rats and controls but significantly lower in the guar gum group. Thus, it was not related to the number of tumors in each group.

Topics: Adenocarcinoma; Animals; Bacteria; Body Weight; Cellulose; Colonic Neoplasms; Dietary Fiber; Dimethylhydrazines; Feces; Glucuronidase; Male; Methylhydrazines; Pectins; Rats

The percent of the carcinogen 1,2-dimethylhydrazine (DMH) bound to a variety of fibers, such as wheat bran, corn bran, citrus pulp, citrus pectin, and alfalfa, was examined at pH values ranging from 1 to 12. The percent of DMH bound to wheat bran increased from 4% at PH 1 to 55% at pH 2 to 77% at pH 12. A sharp rise in carcinogen binding to corn bran occurred between pH 5% of the DMH was bound and pH 8 where 51% of the DMH was bound. The percent of DMH bound to dehydrated citrus pulp also increased as the pH increased with 10% binding observed at pH 1 and with 57% binding observed at pH 12. Between pH 2 and pH 7, the percent of DMH bound to pectin decreased from 60 to 11%. As the pH became more basic, the percent of DMH bound to pectin increased to 42% at pH 12. The sharpest rise in the percent of DMH bound to alfalfa meal occurred between pH 10.5 and pH 12.0. Results from this experiment showed that the affinity to various types of dietary fibers for the colon carcinogen DMH was differentially affected by pH. These results suggested that the protective effect of certain types of dietary fiber against chemically induced colon cancer my in part be attributed to enhanced carcinogen binding by dietary fiber in the colon.

Topics: Cellulose; Chemical Phenomena; Chemistry; Citrus; Colon; Colonic Neoplasms; Dietary Fiber; Dimethylhydrazines; Edible Grain; Humans; Hydrogen-Ion Concentration; Medicago sativa; Methylhydrazines; Pectins

The incidence, distribution, size, and histopathology of colonic tumors induced by parenteral administration of 1,2-dimethylhydrazine were examined in rats fed a chemically defined fiber-free diet or nutritionally and calorically equivalent diets containing either 4.5 or 9.0% purified cellulose or pectin. This double-blind study indicates that cellulose is protective against experimental colonic neoplasia. Although the precise mechanism for this protective effect remains to be elucidated, it was not cellulose dose dependent and appeared to depend on administration during injection of carcinogen. Furthermore, this study provides strong evidence that identical amounts of cellulose and pectin fed as the sole source of fiber in chemically defined diets exert strikingly different effects in relation to development of intestinal neoplasia in this animal model.

Topics: Adenocarcinoma; Animals; Cellulose; Colonic Neoplasms; Dietary Fiber; Dimethylhydrazines; Male; Neoplasms, Experimental; Pectins; Rats

The effect of dietary alfalfa, pectin, and wheat bran on colon carcinogenesis was studied in female inbred F344 rats. Weanling rats were fed semipurified diets containing 0 or 15% alfalfa, pectin, or wheat bran. At 7 weeks of age, all animals except controls were given azoxymethane (AOM) sc at a dose rate of 8 mg/kg body weight/week for 10 weeks or methylnitrosourea (MNU) intrarectally at a dose rate of 2 mg/rat twice a week for 3 weeks. The AOM-treated group was autopsied 40 weeks and the MNU-treated group 30 weeks after the first injection of the carcinogen. No tumors were observed in the colon or other organs of untreated rats fed the various diets. The animals fed the alfalfa diet and treated with MNU had a higher incidence of colon tumors than did those fed the control diet or the diets containing pectin or wheat bran. The incidence of MNU-induced colon tumors did not differ between the animals fed the control diet or the diets containing pectin or wheat bran. However, the incidence of AOM-induced colon tumors in rats fed diets containing pectin or wheat bran was lower than that in rats fed the control diet or the alfalfa diet. These results thus indicate that the effect of fiber in colon carcinogenesis depends on the type of fiber and, possibly, the fiber's mode of action.

Topics: Animals; Azoxymethane; Cellulose; Colonic Neoplasms; Dietary Fiber; Female; Medicago sativa; Methylnitrosourea; Neoplasms, Experimental; Pectins; Rats; Rats, Inbred F344; Triticum

Dietary plant fibre, or plantix, is thought to play a significant role in the pathogenesis of colon cancer in humans. It is a complex polymeric substance that has several distinct components resistant to hydrolysis by the digestive enzymes of humans. These components include cellulose, hemicelluloses, pectins, lignin, gums, mucilages and, in certain instances, algal polysaccharides. These polymers have different physicochemical properties, and recent evidence from experimental studies in animals treated with carcinogens suggests that some may exert protective effects in the intestine and others may enhance colon carcinogenesis. This review synthesizes information on the chemical composition, methods of analysis and physicochemical properties of dietary plant fibre and reviews available studies examining the role of fibre in colonic neoplasia in animals and humans.

Topics: Animals; Bile Acids and Salts; Cellulose; Colonic Neoplasms; Dietary Fiber; Dimethylhydrazines; Eukaryota; Humans; Lignin; Pectins; Polymers; Polysaccharides; Rats

Topics: Absorption; Arteriosclerosis; Bile Acids and Salts; Cellulose; Cholelithiasis; Cholesterol; Colonic Neoplasms; Constipation; Deoxycholic Acid; Dietary Fiber; Humans; Hypercholesterolemia; Intestinal Absorption; Lipid Metabolism; Lithocholic Acid; Pectins; Water

Topics: Bile Acids and Salts; Cellulose; Cholelithiasis; Cholesterol; Colonic Neoplasms; Constipation; Diet; Digestion; Diverticulum, Colon; Feces; Feeding Behavior; Gastrointestinal Diseases; Humans; Hypercholesterolemia; In Vitro Techniques; Intestinal Absorption; Lignin; Metabolic Diseases; Pectins