Dose-dependent inhibition of large intestinal cancer by inositol hexaphosphate in F344 rats

Safety Assessment of Polyol Phosphates as Used in Cosmetics

The Expert Panel for Cosmetic Ingredient Safety (Panel) reviewed the safety of 10 polyol phosphates. Some of the possible functions in cosmetics that are reported for this ingredient group are chelating agents, oral care agents, and skin conditioning agents. The Panel reviewed relevant data relating to the safety of these ingredients under the intended conditions of use in cosmetic formulations, and concluded that Sodium Phytate, Phytic Acid, Phytin, and Trisodium Inositol Triphosphate are safe in cosmetics in the present practices of use and concentration described in the safety assessment. The Panel also concluded that the data are insufficient to determine the safety of the following 6 ingredients as used in cosmetics: Disodium Glucose Phosphate, Manganese Fructose Diphosphate, Sodium Mannose Phosphate, Trisodium Fructose Diphosphate, Xylityl Phosphate, and Zinc Fructose Diphosphate.

Cellular and Molecular Activities of IP6 in Disease Prevention and Therapy

IP6 (phytic acid) is a naturally occurring compound in plant seeds and grains. It is a poly-phosphorylated inositol derivative that has been shown to exhibit many biological activities that accrue benefits in health and diseases (cancer, diabetes, renal lithiasis, cardiovascular diseases, etc.). IP6 has been shown to have several cellular and molecular activities associated with its potential role in disease prevention. These activities include anti-oxidant properties, chelation of metal ions, inhibition of inflammation, modulation of cell signaling pathways, and modulation of the activities of enzymes and hormones that are involved in carbohydrate and lipid metabolism. Studies have shown that IP6 has anti-oxidant properties and can scavenge free radicals known to cause cellular damage and contribute to the development of chronic diseases such as cancers and cardiovascular diseases, as well as diabetes mellitus. It has also been shown to possess anti-inflammatory properties that may modulate immune responses geared towards the prevention of inflammatory conditions. Moreover, IP6 exhibits anti-cancer properties through the induction of cell cycle arrest, promoting apoptosis and inhibiting cancer cell growth. Additionally, it has been shown to have anti-mutagenic properties, which reduce the risk of malignancies by preventing DNA damage and mutations. IP6 has also been reported to have a potential role in bone health. It inhibits bone resorption and promotes bone formation, which may help in the prevention of bone diseases such as osteoporosis. Overall, IP6's cellular and molecular activities make it a promising candidate for disease prevention. As reported in many studies, its anti-inflammatory, anti-oxidant, and anti-cancer properties support its inclusion as a dietary supplement that may protect against the development of chronic diseases. However, further studies are needed to understand the mechanisms of action of this dynamic molecule and its derivatives and determine the optimal doses and appropriate delivery methods for effective therapeutic use.

Impacts and Industrial Applications of Phytic Acid and Phytase

Phytic acid is an antinutritional compound that chelates P and essential divalent cations such as Fe, Ca, and Zn in cereals and major staple crops such as wheat, maize, rice, and sorghum. As a result, these cations cannot be absorbed by monogastric animals or humans: phytic acid has an inhibitory effect on nutrient uptake and its levels are negatively correlated with protein and starch digestibility. However, phytic acid can be degraded by the action of the enzyme phytase. Phytase plays important roles in the degradation of phytic acid and in increasing the nutritional quality of staple foods. Microbial phytase is a versatile enzyme that is beneficial for humans, animals, the environment, and the industry. In this review, we summarise the interaction of phytic acid with micronutrients, various approaches to enhancing the nutritional profile of staple foods by reducing the phytic acid content, and current knowledge of microbial-based phytase as a potential reducer of phytic acid.

Overview of Inositol and Inositol Phosphates on Chemoprevention of Colitis-Induced Carcinogenesis

Chronic inflammation is one of the most common and well-recognized risk factors for human cancer, including colon cancer. Inflammatory bowel disease (IBD) is defined as a longstanding idiopathic chronic active inflammatory process in the colon, including ulcerative colitis and Crohn's disease. Importantly, patients with IBD have a significantly increased risk for the development of colorectal carcinoma. Dietary inositol and its phosphates, as well as phospholipid derivatives, are well known to benefit human health in diverse pathologies including cancer prevention. Inositol phosphates including InsP3, InsP6, and other pyrophosphates, play important roles in cellular metabolic and signal transduction pathways involved in the control of cell proliferation, differentiation, RNA export, DNA repair, energy transduction, ATP regeneration, and numerous others. In the review, we highlight the biologic function and health effects of inositol and its phosphates including the nature and sources of these molecules, potential nutritional deficiencies, their biologic metabolism and function, and finally, their role in the prevention of colitis-induced carcinogenesis.

Inositol Hexaphosphate (IP6) and Colon Cancer: From Concepts and First Experiments to Clinical Application

Multiple human health-beneficial effects have been related to highly phosphorylated inositol hexaphosphate (IP6). This naturally occurring carbohydrate and its parent compound, myo-inositol (Ins), are abundantly present in plants, particularly in certain high-fiber diets, but also in mammalian cells, where they regulate important cellular functions. However, the striking and broad-spectrum anticancer activity of IP6, consistently demonstrated in different experimental models, has been in a spotlight of the scientific community dealing with the nutrition and cancer during the last several decades. First experiments were performed in colon cancer 30 years ago. Since then, it has been shown that IP6 reduces cell proliferation, induces apoptosis and differentiation of malignant cells with reversion to normal phenotype, affecting several critical molecular targets. Enhanced immunity and antioxidant properties also contribute to the tumor cell destruction. Although Ins possesses a modest anticancer potential, the best anticancer results were obtained from the combination of IP6 + Ins. Here we review the first experimental steps in colon cancer, when concepts and hypotheses were put together almost without real knowledge and present clinical studies, that were initiated in colon cancer patients. Available as a dietary supplement, IP6 + Ins has been shown to enhance the anticancer effect of conventional chemotherapy, controls cancer metastases, and improves quality of life in cancer patients. Emerging clinical and still vast amount of experimental data suggest its role either as an adjuvant or as an "alternative" to current chemotherapy for cancer.

Cancer Prevention by Natural Products Introduced into the Diet-Selected Cyclitols

Cancer is now the second leading cause of death worldwide. It is estimated that every year, approximately 9.6 million people die of oncologic diseases. The most common origins of malignancy are the lungs, breasts, and colorectum. Even though in recent years, many new drugs and therapeutic options have been introduced, there are still no safe, effective chemopreventive agents. Cyclitols seem poised to improve this situation. There is a body of evidence that suggests that their supplementation can decrease the incidence of colorectal cancer, lower the risk of metastasis occurrence, lower the proliferation index, induce apoptosis in malignant cells, enhance natural killer (NK) cell activity, protect cells from free radical damage, and induce positive molecular changes, as well as reduce the side effects of anticancer treatments such as chemotherapy or surgery. Cyclitol supplementation appears to be both safe and well-tolerated. This review focuses on presenting, in a comprehensive way, the currently available knowledge regarding the use of cyclitols in the treatment of different malignancies, particularly in lung, breast, colorectal, and prostate cancers.

New options of cancer treatment employing InsP6

Many mechanistic studies have been performed to analyze the cellular functions of the highly phosphorylated molecule inositol hexakisphosphate (InsP₆) in health and disease. While the physiological intracellular functions are well described, the mechanism of potential pharmacological effects on cancer cell proliferation is still controversial. There are numerous studies demonstrating that a high InsP₆ concentration (≥75 µM) inhibits growth of cancer cells in vitro and in vivo. Thus, there is no doubt that InsP₆ exhibits anticancer activity but the mechanism underlying the cellular effects of extracellular InsP₆ on cancer cells is far from being understood. In addition, studies on the inhibitory effect of InsP₆ on cancer progression in animal models ignore aspects of its bioavailability. Here, we review and critically discuss the uptake mechanism and the intracellular involvement in signaling pathways of InsP₆ in cancer cells. We take into account the controversial findings on InsP₆ plasma concentration, which is a critical aspect of pharmacological accessibility of InsP₆ for cancer treatment. Further, we discuss novel findings with respect to the effect of InsP₆ on normal and immune cells as well as on platelet aggregate size. Our goal is to stimulate further mechanistic studies into novel directions considering previously disregarded aspects of InsP₆. Only when we fully understand the mechanism underlying the anticancer activity of InsP₆ novel and more efficient treatment options can be developed.

The effect of combined inositol hexakisphosphate and inositol supplement in streptozotocin-induced type 2 diabetic rats

Inositol hexakisphosphate (IP6) and inositol both regulate insulin secretion, but their combined use in the management of diabetes deserves investigation. The combined effects of IP6 and inositol supplementation were investigated in streptozotocin-induced type 2 diabetic rats. The following groups of rats were studied for 8 weeks: non-diabetic control, non-diabetic high-fat diet control, diabetic untreated, diabetic rats treated with the combination of IP6 and inositol (650 mg/kg bw) and diabetic rats treated with glibenclamide (10 mg/kg bw). High-fat diet and streptozotocin were used to induce type 2 diabetes mellitus in Sprague-Dawley rats. Body weight, blood glucose, glycated haemoglobin, insulin, serum leptin, HOMA-insulin resistance scores, intestinal amylase activity, serum and faecal lipids and food and fluid consumption were measured. Treatment with the combination significantly reduced blood glucose (306 ± 53 mg/dl) and insulin resistance score (1.93 ± 0.45) compared with diabetic controls (522 ± 24 mg/dl and 5.1 ± 0.69 respectively). Serum leptin (2.8 ± 0.6 ng/dl) and faecal triglycerides (108 ± 8 mg/dl) were significantly increased in rats treated with the combination compared with the diabetic control (1.8 ± 0.06 ng/dl and 86 ± 4 mg/dl). Serum triglyceride (47 ± 5.1 mg/dl), total cholesterol (98 ± 3.2 mg/dl) and food intake (26 ± 0.3 g) were significantly reduced by 45%, 25% and 25%, respectively, in rats treated with the combination compared with the diabetic control. Inositol and IP6 combined supplementation may be effective in the management of type 2 diabetes mellitus and related metabolic disorders by regulating some aspects of lipid and carbohydrate metabolism.

Extracellular Mipp1 Activity Confers Migratory Advantage to Epithelial Cells during Collective Migration

Multiple inositol polyphosphate phosphatase (Mipp), a highly conserved but poorly understood histidine phosphatase, dephosphorylates higher-order IPs (IP4-IP6) to IP3. To gain insight into the biological roles of these enzymes, we have characterized Drosophila mipp1. mipp1 is dynamically expressed in the embryonic trachea, specifically in the leading cells of migrating branches at late stages, where Mipp1 localizes to the plasma membrane and filopodia. FGF signaling activates mipp1 expression in these cells, where extensive filopodia form to drive migration and elongation by cell intercalation. We show that Mipp1 facilitates formation and/or stabilization of filopodia in leading cells through its extracellular activity. mipp1 loss decreases filopodia number, whereas mipp1 overexpression increases filopodia number in a phosphatase-activity-dependent manner. Importantly, expression of Mipp1 gives cells a migratory advantage for the lead position in elongating tracheal branches. Altogether, these findings suggest that extracellular pools of inositol polyphosphates affect cell behavior during development.

Suppression of β-catenin and cyclooxygenase-2 expression and cell proliferation in azoxymethane-induced colonic cancer in rats by rice bran phytic acid (PA)

BACKGROUND

Phytic acid (PA) is a polyphosphorylated carbohydrate that can be found in high amounts in most cereals, legumes, nut oil, seeds and soy beans. It has been suggested to play a significant role in inhibition of colorectal cancer. This study was conducted to investigate expression changes of β-catenin and cyclooxygenase-2 (COX-2) and cell proliferation in the adenoma-carcinoma sequence after treatment with rice bran PA by immunocytochemistry.

MATERIALS AND METHODS

Seventy-two male Sprague-Dawley rats were divided into 6 equal groups with 12 rats in each group. For cancer induction two intraperitoneal injections of azoxymethane (AOM) were given at 15 mg/kg bodyweight over a 2-weeks period. During the post initiation phase, two different concentrations of PA, 0.2% (w/v) and 0.5% (w/v) were administered in the diet.

RESULTS

Results of β-catenin, COX-2 expressions and cell proliferation of Ki-67 showed a significant contribution in colonic cancer progression. For β-catenin and COX-2 expression, there was a significant difference between groups at p<0.05. With Ki-67, there was a statistically significant lowering the proliferating index as compared to AOM alone (p<0.05). A significant positive correlation (p=0.01) was noted between COX-2 expression and proliferation. Total β-catenin also demonstrated a significant positive linear relationship with total COX-2 (p=0.044).

CONCLUSIONS

This study indicated potential value of PA extracted from rice bran in reducing colonic cancer risk in rats.

Pro-apoptotic effect of rice bran inositol hexaphosphate (IP6) on HT-29 colorectal cancer cells

Inositol hexaphosphate (IP₆), or phytic acid is a natural dietary ingredient and has been described as a “natural cancer fighter”, being an essential component of nutritional diets. The marked anti-cancer effect of IP₆ has resulted in our quest for an understanding of its mechanism of action. In particular, our data provided strong evidence for the induction of apoptotic cell death, which may be attributable to the up-regulation of Bax and down-regulation of Bcl-xl in favor of apoptosis. In addition, the up-regulation of caspase-3 and -8 expression and activation of both caspases may also contribute to the apoptotic cell death of human colorectal adenocarcinoma HT-29 cells when exposed to IP₆. Collectively, this present study has shown that rice bran IP₆ induces apoptosis, by regulating the pro- and anti-apoptotic markers; Bax and Bcl-xl and via the activation of caspase molecules (caspase-3 and -8).

Preventive inositol hexaphosphate extracted from rice bran inhibits colorectal cancer through involvement of Wnt/β-catenin and COX-2 pathways

Nutritional or dietary factors have drawn attention due to their potential as an effective chemopreventive agent, which is considered a more rational strategy in cancer treatment. This study was designed to evaluate the effect of IP₆ extracted from rice bran on azoxymethane- (AOM-) induced colorectal cancer (CRC) in rats. Initially, male Sprague Dawley rats were divided into 5 groups, with 6 rats in each group. The rats received two intraperitoneal (i.p.) injections of AOM in saline (15 mg/kg body weight) over a 2-week period to induce CRC. IP₆ was given in three concentrations, 0.2% (w/v), 0.5% (w/v), and 1.0% (w/v), via drinking water for 16 weeks. The deregulation of the Wnt/β-catenin signaling pathway and the expression of cyclooxygenase (COX)-2 have been implicated in colorectal tumorigenesis. β-Catenin and COX-2 expressions were analysed using the quantitative RT-PCR and Western blotting. Herein, we reported that the administration of IP₆ markedly suppressed the incidence of tumors when compared to the control. Interestingly, the administration of IP₆ had also markedly decreased β-catenin and COX-2 in colon tumors. Thus, the downregulation of β-catenin and COX-2 could play a role in inhibiting the CRC development induced by IP₆ and thereby act as a potent anticancer agent.

New hypotheses for the health-protective mechanisms of whole-grain cereals: what is beyond fibre?

Epidemiological studies have clearly shown that whole-grain cereals can protect against obesity, diabetes, CVD and cancers. The specific effects of food structure (increased satiety, reduced transit time and glycaemic response), fibre (improved faecal bulking and satiety, viscosity and SCFA production, and/or reduced glycaemic response) and Mg (better glycaemic homeostasis through increased insulin secretion), together with the antioxidant and anti-carcinogenic properties of numerous bioactive compounds, especially those in the bran and germ (minerals, trace elements, vitamins, carotenoids, polyphenols and alkylresorcinols), are today well-recognised mechanisms in this protection. Recent findings, the exhaustive listing of bioactive compounds found in whole-grain wheat, their content in whole-grain, bran and germ fractions and their estimated bioavailability, have led to new hypotheses. The involvement of polyphenols in cell signalling and gene regulation, and of sulfur compounds, lignin and phytic acid should be considered in antioxidant protection. Whole-grain wheat is also a rich source of methyl donors and lipotropes (methionine, betaine, choline, inositol and folates) that may be involved in cardiovascular and/or hepatic protection, lipid metabolism and DNA methylation. Potential protective effects of bound phenolic acids within the colon, of the B-complex vitamins on the nervous system and mental health, of oligosaccharides as prebiotics, of compounds associated with skeleton health, and of other compounds such as alpha-linolenic acid, policosanol, melatonin, phytosterols and para-aminobenzoic acid also deserve to be studied in more depth. Finally, benefits of nutrigenomics to study complex physiological effects of the 'whole-grain package', and the most promising ways for improving the nutritional quality of cereal products are discussed.

Anticarcinogenic efficacy of phytic acid extracted from rice bran on azoxymethane-induced colon carcinogenesis in rats

This study is carried out to determine the potential of phytic acid extracted from rice bran in the suppression of colon carcinogenesis induced by azoxymethane (AOM) in rats. Seventy-two male Sprague-Dawley rats were divided into 6 groups with 12 rats in each group. The intended rats for cancer treatment received two intraperitoneal injections of AOM in saline (15mg/kg bodyweight) over a 2-week period. The treatments of phytic acid were given in two concentrations: 0.2% (w/v) and 0.5% (w/v) during the post-initiation phase of carcinogenesis phase via drinking water. The colons of the animals were analyzed for detection and quantification of aberrant crypt foci (ACF) after 8 weeks of treatment. The finding showed treatment with 0.2% (w/v) extract phytic acid (EPA) gave the greatest reduction in the formation of ACF. In addition, phytic acid significantly suppressed the number of ACF in the distal, middle and proximal colon as compared to AOM alone (p<0.05). For the histological classification of ACF, treatment with 0.5% (w/v) commercial phytic acid (CPA) had the highest percentage (71%) of non-dysplastic ACF followed by treatment with 0.2% (w/v) EPA (61%). Administration of phytic acid also reduced the incidence and multiplicity of total tumors even though there were no significant differences between groups. In conclusion, this study found the potential value of phytic acid extracted from rice bran in reducing colon cancer risk in rats.

Inflammatory bowel disease: a model of chronic inflammation-induced cancer

Chronic inflammation is a well-recognized risk factor for the development of human cancer. Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, is a typical longstanding inflammatory disease of the colon with increased risk for the development of colorectal carcinoma. Several molecular events involved in chronic inflammatory process may contribute to multistage progression of human cancer development, including the overproduction of reactive oxygen and nitrogen species, overproduction/activation of key arachidonic acid metabolites and cytokines/growth factors, and immunity system dysfunction. Multiple animal models of IBD have been established, and in general, these models can be mainly categorized into chemically induced, genetically engineered (transgenic or gene knock-out), spontaneous, and adoptive transferring animal models. This chapter mainly focuses on (1) epidemiologic and molecular evidence on IBD and risk of colorectal cancer, (2) molecular pathogenesis of IBD-induced carcinogenesis, and (3) modeling of IBD-induced carcinogenesis in rodents and its application.

Separation and identification of enzymatically prepared dephosphorylated products of myo-inositolhexakisphosphate using LC-MS

LC-MS technique described here is a new way for the separation and direct determination of UV-Vis insensitive inositol phosphates (InsP(2)-InsP(6)). This circumvents the need of radioisotopic labeling and post-column derivatization techniques. The method involves separation of various enzymatically dephosphorylated derivatives of InsP(6) on C(18)-column using MeOH/H(2)O (30:70 v/v) and their identification using electron spray ionization MS in positive ion mode (+pESI-MS). The LC-MS studies revealed that the purified phytase from Aspergillus niger van Teighem hydrolyzes InsP(6 )in a sequential manner leading to InsP(2 )(InsP(2) x 2Na, t(R) 4.4-4.54 min, base peak m/z 382.9) as the end product.

Molecular mechanism of inositol hexaphosphate-mediated apoptosis in human malignant glioblastoma T98G cells

Glioblastoma is the deadliest brain tumor in humans. Current therapies are mostly ineffective and new agents need to be explored for controlling this devastating disease. Inositol hexaphosphate (IP6) is a phytochemical that is widely found in corns, cereals, nuts, and high fiber-content foods. Previous studies demonstrated anti-cancer properties of IP6 in several in vitro and in vivo tumor models. However, therapeutic efficacy of IP6 has not yet been evaluated in glioblastoma. Here, we explored the molecular mechanism of action of IP6 in human malignant glioblastoma T98G cells. The viability of T98G cells decreased following treatment with increasing doses of IP6. T98G cells exposed to 0.25, 0.5, and 1 mM IP6 for 24 h showed morphological and biochemical features of apoptosis. Western blotting indicated changes in expression of Bax and Bcl-2 proteins resulting in an increase in Bax:Bcl-2 ratio and upregulation of cytosolic levels of cytochrome c and Smac/Diablo, suggesting involvement of mitochondria-dependent caspase cascade in apoptosis. IP6 downregulated cell survival factors such as baculovirus inhibitor-of-apoptosis repeat containing-2 (BIRC-2) protein and telomerase to promote apoptosis. Upregulation of calpain and caspase-9 occurred in course of apoptosis. Increased activities of calpain and caspase-3 cleaved 270 kD alpha-spectrin at specific sites generating 145 kD spectrin break down product (SBDP) and 120 kD SBDP, respectively. Increased caspase-3 activity also cleaved inhibitor of caspase-3-activated DNase and poly(ADP-ribose) polymerase. Collectively, our results demonstrated that IP6 down regulated the survival factors BIRC-2 and telomerase and upregulated calpain and caspase-3 activities for apoptosis in T98G cells.

Anti-angiogenic properties of myo-inositol trispyrophosphate in ovo and growth reduction of implanted glioma

We investigate here the anti-angiogenic properties of the synthetic compound myo-inositol trispyrophosphate (ITPP). By increasing oxy-haemoglobin dissociation, ITPP has the potential to counteract the effects of hypoxia, a critical regulator of angiogenesis and cancer progression. ITPP inhibited angiogenesis of the chorioallantoic membrane (CAM), as analyzed with an original program dedicated to automated quantification of angiogenesis in this model. ITPP also markedly reduced tumor progression and angiogenesis in an experimental model of U87 glioma cell nodules grafted onto the CAM. These results point out the potential of ITPP for the development of a new class of anti-angiogenic and anti-cancer compounds.

Protection against cancer by dietary IP6 and inositol

Inositol hexaphosphate (IP(6)) is a naturally occurring polyphosphorylated carbohydrate, abundantly present in many plant sources and in certain high-fiber diets, such as cereals and legumes. In addition to being found in plants, IP(6) is contained in almost all mammalian cells, although in much smaller amounts, where it is important in regulating vital cellular functions such as signal transduction, cell proliferation, and differentiation. For a long time IP(6) has been recognized as a natural antioxidant. Recently IP(6) has received much attention for its role in cancer prevention and control of experimental tumor growth, progression, and metastasis. In addition, IP(6) possesses other significant benefits for human health, such as the ability to enhance immune system, prevent pathological calcification and kidney stone formation, lower elevated serum cholesterol, and reduce pathological platelet activity. In this review we show the efficacy and discuss some of the molecular mechanisms that govern the action of this dietary agent. Exogenously administered IP(6) is rapidly taken up into cells and dephosphorylated to lower inositol phosphates, which further affect signal transduction pathways resulting in cell cycle arrest. A striking anticancer action of IP(6) was demonstrated in different experimental models. In addition to reducing cell proliferation, IP(6) also induces differentiation of malignant cells. Enhanced immunity and antioxidant properties also contribute to tumor cell destruction. Preliminary studies in humans show that IP(6) and inositol, the precursor molecule of IP(6), appear to enhance the anticancer effect of conventional chemotherapy, control cancer metastases, and improve quality of life. Because it is abundantly present in regular diet, efficiently absorbed from the gastrointestinal tract, and safe, IP(6) + inositol holds great promise in our strategies for cancer prevention and therapy. There is clearly enough evidence to justify the initiation of full-scale clinical trials in humans.

Phytic acid modulates in vitro IL-8 and IL-6 release from colonic epithelial cells stimulated with LPS and IL-1beta

Phytic acid (PA), a major fiber-associated component of wheat bran and legumes, is physiologically present in the human large gut. The aim of this study was to examine the role of PA in immunologic function of intestinal epithelial cells by analyzing its effect on interleukin (IL)-8 and IL-6 secretion by colonocytes and its role in the response of these cells to bacterial lipopolysaccharides (LPS) and IL-1beta. The human colon cell line Caco-2 was exposed to LPS isolated from two strains of Desulfovibrio desulfuricans, wild intestinal and type soil strains, as well as to LPS from E. coli. Cells were also treated with IL-1beta and with a combination of LPS and IL-1beta. PA had a suppressive effect on IL-8 basal release and it dose dependently reduced IL-8 secretion by colonocytes stimulated with LPS and IL-1beta. On the contrary, PA increased constitutive IL-6 secretion and exhibited differentiated effects on LPS responsiveness of cells depending on its concentration and LPS origin. PA was also an efficient down-regulator of IL-6 secretion stimulated by binary actions of LPS and IL-1beta. The ability of PA to modulate IL-8 and IL-6 release suggests that PA present in the intestinal milieu may exert immunoregulatory effects on colonic epithelium under physiological conditions or during microbe-induced infection/inflammation in order to maintain the colonic mucosa in a noninflammatory state or to counteract infection.

Inositol hexaphosphate (IP6): a novel treatment for pancreatic cancer

BACKGROUND

Inositol hexaphosphate (IP6) is a naturally occurring polyphosphorylated carbohydrate found in food sources high in fiber content. IP6 has been reported to have significant inhibitory effects against a variety of primary tumors including breast and colon. The effects of IP6 have not been evaluated in pancreatic cancer. We hypothesized that IP6 would significantly inhibit cell growth and increase the apoptotic rate of pancreatic cancer in vitro.

MATERIALS AND METHODS

Two pancreatic cancer cell lines (MIAPACA and PANC1) were cultured using standard techniques and treated with IP6 at doses of 0.5, 1.0, and 5.0 mm. Cell viability was measured by MTT at 24 and 72 h. Apoptosis was evaluated by Annexin V-FITC and results calculated using FACS analysis. Statistical analysis was performed by ANOVA.

RESULTS

Significant reductions (P < 0.01) in cellular proliferation were observed with all IP6 concentrations tested in both cell lines and at both time points. Reductions in cell proliferation ranged from 37.1 to 91.5%. IP6 increased early and late apoptotic activity (P < 0.01).

CONCLUSIONS

Treatment of pancreatic cancer with the common dietary polyphosphorylated carbohydrate IP6 significantly decreased cellular growth and increased apoptosis. Our findings suggest that IP6 has the potential to become an effective adjunct for pancreatic cancer treatment. Further in vivo and human studies are needed to evaluate safety and clinical utility of this agent in patients with pancreatic cancer.

Cellular formation of DNA and RNA and the relationship to tumour cell development

A hypothesis concerning the mode of formation of the components of DNA and RNA in living cells is described. This is based on the reversible hydration and dehydration of polyphosphoric acids in the cell. It is shown that formation of DNA in the cell directs reacting chemicals from the outer membrane of the cell towards the centre leading to the conclusion that all cells operate in the same manner. Cell products are therefore a function of the nature and concentration of chemicals in the source of supply. The origin of tumour cells is proposed as the formation of distorted nuclei. Suggestions are advanced as to means of correcting this situation.

Cancer inhibition by inositol hexaphosphate (IP6) and inositol: from laboratory to clinic

Inositol hexaphosphate (IP6) is a naturally occurring polyphosphorylated carbohydrate that is present in substantial amounts in almost all plant and mammalian cells. It was recently recognized to possess multiple biological functions. A striking anticancer effect of IP6 was demonstrated in different experimental models. Inositol is also a natural constituent possessing moderate anticancer activity. The most consistent and best anticancer results were obtained from the combination of IP6 plus inositol. In addition to reducing cell proliferation, IP6 increases differentiation of malignant cells, often resulting in a reversion to normal phenotype. Exogenously administered IP6 is rapidly taken into the cells and dephosphorylated to lower-phosphate inositol phosphates, which further interfere with signal transduction pathways and cell cycle arrest. Enhanced immunity and antioxidant properties can also contribute to tumor cell destruction. However, the molecular mechanisms underlying this anticancer action are not fully understood. Because it is abundantly present in regular diet, efficiently absorbed from the gastrointestinal tract, and safe, IP6 holds great promise in our strategies for the prevention and treatment of cancer. IP6 plus inositol enhances the anticancer effect of conventional chemotherapy, controls cancer metastases, and improves the quality of life, as shown in a pilot clinical trial. The data strongly argue for the use of IP6 plus inositol in our strategies for cancer prevention and treatment. However, the effectiveness and safety of IP6 plus inositol at therapeutic doses needs to be determined in phase I and phase II clinical trials in humans.

Inositol hexaphosphate (IP6) enhances the anti-proliferative effects of adriamycin and tamoxifen in breast cancer

The current treatment of breast carcinomas recognizes the importance of combination therapy in order to increase efficacy and decrease side effects of conventional chemotherapy. Inositol hexaphosphate (IP6), a naturally occurring polyphosphorylated carbohydrate, has shown a significant anti-cancer effect in various in vivo and in vitro models, including breast cancer. In this study, we investigated the in vitro growth inhibitory activity of IP6 in combination with adriamycin or tamoxifen, against three human breast cancer cell lines: estrogen receptor (ER) alpha-positive MCF-7, ER alpha-negative MDA-MB 231 and adriamycin-resistant MCF-7 (MCF-7/Adr) using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Much lower concentrations of IP6 were required after 96 h of treatment to inhibit the growth of MCF-7/Adr cells than MCF-7 cells; the IC50 for MCF-7/Adr cells was 1.26 mM compared to 4.18 mM for MCF-7 cells. The ER-negative MDA-MB 231 cells were also highly sensitive to IP6 with IC50 being 1.32 mM. To determine the effects of IP6 in combination with either adriamycin or tamoxifen, the median effect principle and Webb's fraction method were used to determine the combination index (CI) and the statistical differences. Growth suppression was markedly increased when IP6 was administered prior to the addition of adriamycin, especially against MCF-7 cells (CI = 0.175 and p < 0.0001). Synergism was also observed when IP6 was administered after tamoxifen in all three cell lines studied (CI = 0.343, 0.701 and 0.819; p < 0.0001, p = 0.0003 and 0.0241 for MCF-7/Adr, MCF-7 and MDA-MB 231, respectively). The growth of primary culture of breast cancer cells from patients was inhibited by IP6 with LC50 values ranging from 0.91 to 5.75 mM (n = 10). Our data not only confirm that IP6 alone inhibits the growth of breast cancer cells; but it also acts synergistically with adriamycin or tamoxifen, being particularly effective against ER alpha-negative cells and adriamycin-resistant cell lines.

Phytic acid (IP6), novel broad spectrum anti-neoplastic agent: a systematic review

INTRODUCTION

Phytic acid or IP6 has been extensively studied in animals and is being promoted as an anti-cancer agent in health food stores. It is naturally found in legumes, wheat bran, and soy foods. It is believed to be the active ingredient that gives these substances their cancer fighting abilities. Proposed mechanisms of action include gene alteration, enhanced immunity, and anti-oxidant properties.

METHODS

A Medline search from 1966 to May 2002 using the keywords phytic acid and cancer, and limiting the search to the subheadings of therapeutic uses, prevention, and adverse effects revealed 28 studies. These studies were included in the review.

RESULTS

A great majority of the studies were done in animals and showed that phytic acid had anti-neoplastic properties in breast, colon, liver, leukemia, prostate, sarcomas, and skin cancer. There were no human studies. Side effects included chelation of multivalent cations, and an increase in bladder and renal papillomas. This increase in papilloma formation only occurred with the sodium salt of phytic acid. It did not occur with either the potassium or magnesium salts.

CONCLUSIONS

There is a large body of animal evidence to show that phytic acid may have a role in both the prevention and treatment of many forms of cancer. There is clearly enough evidence to justify the initiation of Phase I and Phase II clinical trials in humans.

Pathway of dephosphorylation of myo-inositol hexakisphosphate by phytases of legume seeds

Using a combination of high-performance ion chromatography analysis and kinetic studies, the pathway of dephosphorylation of myo-inositol hexakisphosphate by the phytases purified from faba bean and lupine seeds, respectively, was established. The data demonstrate that the legume seed phytases under investigation dephosphorylate myo-inositol hexakisphosphate in a stereospecific way. The phytase from faba bean seeds and the phytase LP2 from lupine seeds degrade phytate by sequential removal of phosphate groups via D-Ins(1,2,3,5,6)P(5), D-Ins(1,2,5,6)P(4), D-Ins(1,2,6)P(3), and D-Ins(1,2)P(2) to finally Ins(2)P, whereas the phytases LP11 and LP12 from lupine seeds generate the final degradation product Ins(2)P via D-Ins(1,2,4,5,6)P(5), D-Ins(1,2,5,6)P(4), D-Ins(1,2,6)P(3), and D-Ins(1,2)P(2).

The pathway of dephosphorylation of myo-inositol hexakisphosphate by phytate-degrading enzymes of different Bacillus spp

The pathway of dephosphorylation of myo-inositol hexakisphosphate by the phytate-degrading enzymes of Bacillus subtilis 168, Bacillus amyloliquefaciens ATCC 15841, and Bacillus amyloliquefaciens 45 was established using a combination of high-performance ion chromatography analysis and kinetic studies. The data demonstrate that all the Bacillus phytate-degrading enzymes under investigation dephosphorylate myo-inositol hexakisphosphate by sequential removal of phosphate groups via two independent routes; the routes proceed via D-Ins(1,2,4,5,6)P5 to Ins(2,4,5,6)P4 to finally Ins(2,4,6)P3 or D-Ins(2,5,6)P3 and via D-Ins(1,2,4,5,6)P5 to D-Ins(1,2,5,6)P4 to finally D-Ins(1,2,6)P3. The resulting myo-inositol trisphosphate D-Ins(1,2,6)P3 was degraded via D-Ins(2,6)P2 to finally Ins(2)P after prolonged incubation times in combination with increased enzyme concentration.

Anti‐cancer function of phytic acid

Summary Inositol hexaphosphate (InsP6 a.k.a. phytic acid or IP6) is ubiquitous. In the plant kingdom it is particularly abundant in cereals and legumes; in much smaller amounts IP6 and its lower phosphorylated forms (IP1−5) are contained in most mammalian cells, where they are important in regulating vital cellular functions. Both in vivo and in vitro experiments have demonstrated striking anticancer (preventive as well as therapeutic) effects of IP6. Inositol also is anti‐carcinogenic, albeit to a lesser extent; it acts synergistically IP6 in inhibiting cancer. In addition to reduction in cell proliferation, IP6 increases differentiation of malignant cells often resulting in reversion to the normal phenotype. IP6 is quickly absorbed from the rat stomach and upper intestine and distributed as inositol and IP1. In vitro, it is instantaneously taken up by malignant cells undergoing variable dephosphorylation to inositol and IP1−5, pointing towards their role in mediating the action of IP6. In humans, IP6 has recently been detected in urine, plasma and other biological fluids; the levels fluctuating with ingestion or deprivation of IP6 or IP6‐rich diet. As IP6 is high in high‐fibre diets, these also may explain, at least in part, the epidemiological observation showing the association of ingesting high‐fibre diets with a lower incidence of certain cancers. Along with safety, the reproducible efficacy of IP6 and inositol in the prevention of cancer in laboratory animals warrant their inclusion in our strategies for cancer prevention and perhaps therapy in humans. Aside from the anticancer action, IP6 and inositol also have numerous other health benefits. All these facts of normal physiological presence of IP6 in our body the level of which fluctuates with intake, association of an IP6‐rich diet with low incidence of several diseases and vice versa, and finally reversal of some of these conditions, at least in part, by IP6 supplementation strongly argue in favour of its inclusion as an essential nutrient or perhaps a vitamin.

Most effective colon cancer chemopreventive agents in rats: a systematic review of aberrant crypt foci and tumor data, ranked by potency

Potential chemopreventive agents for colorectal cancer are assessed in rodents. We speculated that the magnitude of the effect is meaningful and ranked all published agents according to their potency. Data were gathered systematically from 137 articles with the aberrant crypt foci (ACF) end point and from 146 articles with the tumor end point. The potency of each agent to reduce the number of ACF is listed in one table and the potency of each agent to reduce the tumor incidence in another table. Both tables are shown in this review and on a website with sorting abilities (http://www.inra.fr/reseau-nacre/sci-memb/corpet/indexan.html). Potency was estimated as the ratio of the value in control rats to the value in treated rats. From each article, only the most potent agent was kept, except in articles reporting the effect of more than seven agents. Among the 186 agents in the ACF table, the median agent reduced the number of ACF by one-half. The most potent agents to reduce azoxymethane-induced ACF were Pluronic, polyethylene glycol, perilla oil with beta-carotene, and sulindac sulfide. Among the 160 agents in the tumor table, the median agent reduced the tumor incidence in rats by one-half. The most potent agents to reduce the incidence of azoxymethane-induced tumors were celecoxib, a protease inhibitor from soy, difluoromethylornithine with piroxicam, polyethylene glycol, and a thiosulfonate. For the 57 agents present in both tables, a significant correlation (r) was found between the potencies against ACF and tumors (r = 0.45, P < 0.001); without celecoxib, a major outlying point in the correlation, r = 0.68 (P < 0.001, n = 56). In conclusion, this review gathers most known chemopreventive agents, ranks the most promising agents against colon carcinogenesis in rats or mice, and further supports the use of ACF as a surrogate end point for tumors in rats.

Stereospecificity of myo-inositol hexakisphosphate dephosphorylation by a phytate-degrading enzyme of Escherichia coli

Using a combination of high-performance ion chromatography analysis and kinetic studies, the stereospecificity of myo-inositol hexakisphosphate dephosphorylation by the phytate-degrading enzyme P2 of Escherichia coli was established. High-performance ion chromatography revealed that the phytate-degrading enzyme P2 of E. coli degrades myo-inositol hexakisphosphate by stepwise dephosphorylation via D/L-Ins(1,2,3,4,5)P(5), D/L-Ins(2,3,4,5)P(4), D/L-Ins(2,4,5)P(3) or D/L-Ins(1,2,4)P(3), D/L-Ins(1,2)P(2) or Ins(2, 5)P(2) or D/L-Ins(4,5)P(2) to finally Ins(2)P or Ins(5)P. Kinetic parameters for myo-inositol pentakisphosphate hydrolysis by E. coli and wheat phytase, respectively, showed that the myo-inositol pentakisphosphate intermediate produced either by the phytate-degrading enzyme of wheat or E. coli are not identical. The absolute configuration of the myo-inositol pentakisphosphate isomer produced by the E. coli enzyme was determined by taking into consideration that wheat phytase produces predominantly the D-Ins(1, 2,3,5,6)P(5) isomer (Lim, P.E., Tate, M.E., 1973. The phytases: II. Properties of phytase fraction F(1) and F(2) from wheat bran and the myo-inositol phosphates produced by fraction F(2). Biochim. Biophys. Acta 302, 326-328). The data demonstrate that the phytate-degrading enzyme P2 of E. coli dephosphorylates myo-inositol hexakisphosphate in a stereospecific way by sequential removal of phosphate groups via D-Ins(1,2,3,4,5)P(5), D-Ins(2,3,4,5)P(4), D-Ins(2,4,5)P(3), Ins(2,5)P(2) to finally Ins(2)P (notation 6/1/3/4/5).

Protective effect of phytic acid on oxidative DNA damage with reference to cancer chemoprevention

Phytic acid (myo-inositol hexaphosphate) is one of the most promising cancer chemopreventive agents. We investigated the mechanism by which phytic acid expresses preventive action to cancer. Phytic acid inhibited the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine in cultured cells treated with an H2O2-generating system, although it did not scavenge H2O2. Site-specific DNA damage by H2O2 and Cu(II) at GG and GGG sequences was inhibited by phytic acid, but not by myo-inositol. Phytic acid alone did not cause DNA damage and thus, it should not act as a prooxidant. We conclude that phytic acid acts as an antioxidant to inhibit the generation of reactive oxygen species from H2O2 by chelating metals, resulting in chemoprevention of cancer.

Stereospecificity of myo-inositol hexakisphosphate dephosphorylation by a phytate-degrading enzyme of baker's yeast

During food processing such as baking, phytate is dephosphorylated to produce degradation products, such as myo-inositol pentakis-, tetrakis-, tris-, bis-, and monophosphates. Certain myo-inositol phosphates have been proposed to have positive effects on human health. The position of the phosphate groups on the myo-inositol ring is thereby of great significance for their physiological functions. Using a combination of high-performance ion chromatography analysis and kinetic studies the stereospecificity of myo-inositol hexakisphosphate dephosphorylation by a phytate-degrading enzyme from baker's yeast (Saccharomyces cerevisiae) was established. The data demonstrate that the phytate-degrading enzyme from baker's yeast dephosphorylates myo-inositol hexakisphosphate in a stereospecific way by sequential removal of phosphate groups via D-Ins(1,2,4,5,6)P(5), D-Ins(1,2,5,6)P(4), D-Ins(1,2,6)P(3), D-Ins(1,2)P(2), to finally Ins(2)P (notation 3/4/5/6/1). Knowledge of the absolute stereochemical specificity of the baker's yeast phytase allows use of the enzyme to produce defined myo-inositol phosphates for kinetic and physiological studies.

Modeling the effect of temperature and pH on activity of enzymes: the case of phytases

In this study, the behavior of enzyme activity as a function of pH and temperature is modeled on the basis of fundamental considerations. A formulation is developed that includes the activation of enzymes with increasing temperatures and the deactivation of enzymes at higher temperature, together with the effect of protonation and hydroxylation on activity at various constant pH levels. The model is calibrated and validated against an extensive set of experimental data on phytases from seven different origins. The percentage variance accounted for (R(2)(adj)), obtained by statistical nonlinear regression analysis on all data sets, was shown to range from 97.6% to 99.5%. The equilibrium constant of protonation and hydroxylation proved to be independent of temperature.

The role of phytic acid in legumes: antinutrient or beneficial function?

This review describes the present state of knowledge about phytic acid (phytate), which is often present in legume seeds. The antinutritional effects of phytic acid primarily relate to the strong chelating associated with its six reactive phosphate groups. Its ability to complex with proteins and particularly with minerals has been a subject of investigation from chemical and nutritional viewpoints. The hydrolysis of phytate into inositol and phosphates or phosphoric acid occurs as a result of phytase or nonenzymatic cleavage. Enzymes capable of hydrolysing phytates are widely distributed in micro-organisms, plants and animals. Phytases act in a stepwise manner to catalyse the hydrolysis of phytic acid. To reduce or eliminate the chelating ability of phytate, dephosphorylation of hexa- and penta-phosphate forms is essential since a high degree of phosphorylation is necessary to bind minerals. There are several methods of decreasing the inhibitory effect of phytic acid on mineral absorption (cooking, germination, fermentation, soaking, autolysis). Nevertheless, inositol hexaphosphate is receiving increased attention owing to its role in cancer prevention and/or therapy and its hypocholesterolaemic effect.

Dietary factors in human colorectal cancer

Colorectal cancer is a significant cause of mortality in Western societies. The progression of the disease from normal colonic epithelium to the acquisition of the malignant phenotype is accompanied by numerous genetic and epigenetic alterations. Compelling experimental and epidemiological evidence indicates that diet and nutrition are key factors in the modulation of colorectal cancer. A salient case in point is the recent observation that a dietary regimen based on a Western-style diet provokes in the rodent colon the appearance of preneoplastic lesions in the absence of any genotoxic insult. This review mainly describes dietary factors that inhibit the development and progression of colorectal cancer. Much is unknown about the precise mechanisms of action of chemically disparate nutrients and how they interfere with the development and progression of this disease. Current knowledge about this important issue is summarized. We believe that continuing scrutiny and precise assessment of the benefits (and potential risks) of nutrients in the treatment and prevention of colorectal cancer will prove significant to controlling this devastating disease.

Dietary and chemopreventive strategies

Dietary and chemopreventive strategies may be used to stem the development of human cancer. This emerging field has increasing potential for influencing cancer incidence rates in defined high-risk groups and the general population. Colorectal cancer in particular, although the fourth most common cancer in the world, due to its temporal nature is amenable to both dietary and chemopreventive strategies. This chapter does not attempt to be all-embracing, but to serve its purpose will concentrate on major natural components of the diet and chemical additions that may be added to it, i.e. non-steroidal anti-inflammatory drugs, which by a common mechanism may reduce risk and recurrence of colorectal cancer.

Modulatory influence of arecoline on the phytic acid-altered hepatic biotransformation system enzymes, sulfhydryl content and lipid peroxidation in a murine system

The potential of arecoline alkaloid, by direct or translactational exposure, to modify the chemopreventive efficacy of phytic acid, via modulation of hepatic biotransformation system enzymes and antioxidant defence mechanism, was assessed in a murine system. Phytic acid (500 or 1000 mg/kg b.w. per day) induced a statistically significant increase in the hepatic levels of glutathione S-transferase (GST) and sulfhydryl (-SH) in murine females and suckling neonates. The elevated levels of hepatic cytochrome b5 (Cyt. b5), cytochrome P-450 (Cyt. P-450) and the depleted level of malondialdehyde (MDA) were observed in the lactating mice. Arecoline (20 mg/kg b.w. per day) alone did not modulate the hepatic GST and -SH levels although it induced a statistically significant increase in the levels of Cyt. b5, Cyt. P-450 and MDA in the murine system. Phytic acid-modulated hepatic levels of phase II components were depressed whereas phase I enzymes and lipid peroxides were further elevated by arecoline-plus-phytic acid treatment. The implications of direct or translactational modulation in the competing potential pathways of biotransformation system enzymes in the process of chemical carcinogenesis are discussed.

Colon tumor promotion: is it a selective process? Effects of cholate, phytate, and food restriction in rats on proliferation and apoptosis in normal and aberrant crypts

Promotion would suppose the selection of initiated cells. We tested the selection of aberrant crypt cells by cholic acid, a colon cancer promoter, and the effect of protectors, phytate and food restriction. After an azoxymethane injection, rats were allocated to a control diet, or to supplements of cholic acid, sodium phytate, or to a 50% food restriction. The proliferation and apoptosis of 1200 crypts were assessed, after immuno-staining for BrdU. Cholic acid increased the proliferation of aberrant crypts but not of normal crypts. Phytate and food restriction decreased the proliferation of normal crypts, but not of aberrant crypts. Apoptosis was not affected by diets. Results support the hypothesis that cholic acid can select initiated cells in the colon.