Chemopreventive efficacy of inositol hexaphosphate against prostate tumor growth and progression in TRAMP mice

Transporter targeted-carnitine modified pectin-chitosan nanoparticles for inositol hexaphosphate delivery to the colon: An in silico and in vitro approach

Orally targeted delivery systems have attracted ample interest in colorectal cancer management. In this investigation, we developed Inositol hexaphosphate (IHP) loaded Tripolyphosphate (Tr) crosslinked Pectin (Pe) Chitosan (Ch) nanoparticles (IHP@Tr*Pe-Ch-NPs) and modified them with l-Carnitine (CE) (CE-IHP@Tr*Pe-Ch-NPs) to improve uptake in colon cells. The formulated CE-IHP@Tr*Pe-Ch-NPs displayed a monodisperse distribution with 219.3 ± 5.5 nm diameter and 30.17 mV surface charge. Cell-line studies revealed that CE-IHP@Tr*Pe-Ch-NPs exhibited excellent biocompatibility in J774.2 and decreased cell viability in DLD-1, HT-29, and MCF7 cell lines. More cell internalization was seen in HT-29 and MCF7 due to overexpression of the OCTN2 and ATB0,+ transporter (CE transporters) compared to DLD-1. The cell cycle profile, reactive oxygen species, apoptosis, and mitochondrial membrane potential assays were performed to explore the chemo-preventive mechanism of CE-IHP@Tr*Pe-Ch-NPs. Moreover, the in-silico docking studies revealed enhanced interactive behavior of CE-IHP@Tr*Pe-Ch-NPs, thereby proving their targeting ability. All the findings suggested that CE-IHP@Tr*Pe-Ch-NPs could be a promising drug delivery approach for colon cancer targeting.

Ethyl Pyruvate; from Liver Preservation Solutions University of Wisconsin (UW) Increases the Effectiveness of the Solution

BACKGROUND

The most important factor affecting the success rate of liver transplants is the preservation of the normal histologic and biochemical properties of the cells in the tissue taken. The study aimed to identify the possible increase in efficacy of ethyl pyruvate, which has a hepatoprotective effect, on the University of Wisconsin (UW) solution.

METHODS

Rats were randomly selected and divided into 4 groups. After a laparotomy, the small intestines were removed from the abdomen and the portal pedicle was identified. Arterial and venous circulation of the liver was interrupted. After the portal vein was cannulated (and the distal of the portal pedicle was ligated, the liver was perfused with a solution. Perfusion solution was selected as Ringer Lactate in Group 1. In group 2, UW solution was chosen as the perfusion solution. In Group 3, the perfusion solution was chosen as the UW solution, but ethyl pyruvate at a dose of 40 mg/kg was administered intraperitoneally to the experimental animals 30 minutes before hepatectomy. In Group 4, as a perfusion solution, a UW solution with 40 mg/kg dose of ethyl pyruvate added to it was used.

RESULTS

With TUNEL and Caspase-3 staining, a significant decrease was found in the apoptosis rates of Groups 2, 3, and 4 at the 12th hour post hepatectomy when compared with Group 1. When the morphometric liver sinusoid/parenchyma ratios and vena centralis diameters of the groups were examined, it was found that all preservation solutions containing the UW solution were more protective than the RL solution.

CONCLUSIONS

Ethyl pyruvate is regarded as a promising agent that can increase the effect of the UW solution on organ preservation solutions. Because this study is the first in literature to apply ethyl pyruvate in preservation solutions, additional studies with larger series and different doses are needed.

Crosslinked and PEGylated Pectin Chitosan Nanoparticles for Delivery of Phytic Acid to Colon

Polysaccharide-based nanoparticles (NPs) such as pectin/ chitosan (PN/CN) had always been of greatest interest because of their excellent solubility, biocompatibility, and higher suitability for oral drug delivery. This study employed blending-crosslinking of polymers (PN&CN) followed by emulsification-solvent evaporation to prepare and compare two sets of PEGylated NPs to deliver phytic acid (IP6) to colon orally as it has potential to manage colon cancer but fails to reach colon when ingested in pure form. The first set was crosslinked with Glutaraldehyde (GE) (GE*PN-CN-NPs) while the second set was crosslinked with sodium tripolyphosphate (TPP) (TPP*PN-CN-NPs). IP6-loaded-GE/TPP*PN-CN-NPs were optimized using a central composite design. Developed TPP*PN-CN-NPs had a smaller size (210.6±7.93nm) than GE*PN-CN-NPs (557.2±5.027nm). Prepared NPs showed <12% IP6 release at pH 1.2 whereas >80% release was observed at pH 7.4. Further, NPs were explored for cytocompatibility in J774.2 cell lines, cytotoxicity, and cellular uptake in HT-29 and DLD-1 cell lines. While exhibiting substantial cytotoxicity and cellular uptake in HT-29 and DLD-1, the NPs were deemedsafe in J774.2. The PEGylated-TPP*PN-CN-NPs showed time-dependent uptake in J774.2 cell lines. Conclusively, the employed NP development method successfully delivered IP6 to colon and may also open avenues for the oral delivery of other drugs to colon.

Stage-Specific Effect of Inositol Hexaphosphate on Cancer Stem Cell Pool during Growth and Progression of Prostate Tumorigenesis in TRAMP Model

Herein, we assessed the stage-specific efficacy of inositol hexaphosphate (IP6, phytic acid), a bioactive food component, on prostate cancer (PCa) growth and progression in a transgenic mouse model of prostate cancer (TRAMP). Starting at 4, 12, 20, and 30 weeks of age, male TRAMP mice were fed either regular drinking water or 2% IP6 in water for ~8-15 weeks. Pathological assessments at study endpoint indicated that tumor grade is arrested at earlier stages by IP6 treatment; IP6 also prevented progression to more advanced forms of the disease (~55-70% decrease in moderately and poorly differentiated adenocarcinoma incidence was observed in advanced stage TRAMP cohorts). Next, we determined whether the protective effects of IP6 are mediated via its effect on the expansion of the cancer stem cells (CSCs) pool; results indicated that the anti-PCa effects of IP6 are associated with its potential to eradicate the PCa CSC pool in TRAMP prostate tumors. Furthermore, in vitro assays corroborated the above findings as IP6 decreased the % of floating PC-3 prostaspheres (self-renewal of CSCs) by ~90%. Together, these findings suggest the multifaceted chemopreventive-translational potential of IP6 intervention in suppressing the growth and progression of PCa and controlling this malignancy at an early stage.

African nightshades (Solanum nigrum complex): The potential contribution to human nutrition and livelihoods in sub-Saharan Africa

Achieving zero hunger in sub-Saharan Africa (SSA) without minimizing postharvest losses of agricultural products is impossible. Therefore, a holistic approach is vital to end hunger, simultaneously improving food security, diversity, and livelihoods. This review focuses on the African nightshades (ANS) Solanum spp. contribution to improving food and nutrition security in SSA. Different parts of ANS are utilized as food and medicine; however, pests and diseases hinder ANS utilization. African nightshade is rich in micronutrients such as β-carotene, vitamins C and E, minerals (iron, calcium, and zinc), and dietary fiber. The leaves contain a high amount of nutrients than the berries. Proper utilization of ANS can contribute to ending hidden hunger, mainly in children and pregnant women. Literature shows that ANS contains antinutritional factors such as oxalate, phytate, nitrate, and alkaloids; however, their quantities are low to cause potential health effects. Several improved varieties with high yields, rich in nutrients, and low alkaloids have been developed in SSA. Various processing and preservation techniques such as cooking, drying, and fermentation are feasible techniques for value addition on ANS in SSA; moreover, most societies are yet to adopt them effectively. Furthermore, promoting value addition and commercialization of ANS is of importance and can create more jobs. Therefore, this review provides an overview of ANS production and challenges that hinder their utilization, possible solutions, and future research suggestions. This review concludes that ANS is an essential nutritious leafy vegetable for improving nutrition and livelihoods in SSA.

Review of the beneficial and anti-nutritional qualities of phytic acid, and procedures for removing it from food products

Phytic acid (PA) is the primary phosphorus reserve in cereals and legumes which serves the biosynthesis needs of growing tissues during germination. It is generally considered to be an anti-nutritional factor found in grains because it can bind to minerals, proteins, and starch, limiting their bioavailability. However, this same mineral binding property can also confer a number of health benefits such as reducing the risk of certain cancers, supporting heart health, and managing renal stones. In addition, the ability of PA to bind minerals allows it to be used in certain food quality applications such as stabilizing the green color of vegetables, preventing lipid peroxidation, and reducing enzymatic browning in fruits/vegetables. These beneficial properties create a potential for added-value applications in the utilization of PA in many new areas. Many possible processing techniques for the preparation of raw materials in the food industry can be used to reduce the concentration of PA in foods to mitigate its anti-nutritional effects. In turn, the recovered PA by-products could be available for novel uses. In this review, a general overview of the beneficial and anti-nutritional effects of PA will be discussed and then dephytinization methods will be explained.

Broad Spectrum Anticancer Activity of Myo-Inositol and Inositol Hexakisphosphate

Inositols (myo-inositol and inositol hexakisphosphate) exert a wide range of critical activities in both physiological and pathological settings. Deregulated inositol metabolism has been recorded in a number of diseases, including cancer, where inositol modulates different critical pathways. Inositols inhibit pRB phosphorylation, fostering the pRB/E2F complexes formation and blocking progression along the cell cycle. Inositols reduce PI3K levels, thus counteracting the activation of the PKC/RAS/ERK pathway downstream of PI3K activation. Upstream of that pathway, inositols disrupt the ligand interaction between FGF and its receptor as well as with the EGF-transduction processes involving IGF-II receptor and AP-1 complexes. Additionally, Akt activation is severely impaired upon inositol addition. Downregulation of both Akt and ERK leads consequently to NF-kB inhibition and reduced expression of inflammatory markers (COX-2 and PGE2). Remarkably, inositol-induced downregulation of presenilin-1 interferes with the epithelial-mesenchymal transition and reduces Wnt-activation, β-catenin translocation, Notch-1, N-cadherin, and SNAI1 release. Inositols interfere also with the cytoskeleton by upregulating Focal Adhesion Kinase and E-cadherin and decreasing Fascin and Cofilin, two main components of pseudopodia, leading hence to invasiveness impairment. This effect is reinforced by the inositol-induced inhibition on metalloproteinases and ROCK1/2 release. Overall, these effects enable inositols to remodel the cytoskeleton architecture.

N-Ethyl-N-nitrosourea-induced transplacental lung tumor development and its control: molecular modulations for tumor susceptibility in a mouse model

The development of lung tumors after transplacental N-ethyl-N-nitrosourea (ENU) exposure has been demonstrated in Swiss and Balb/c mice F1 mice.

Amifostine enhances the antioxidant and hepatoprotective effects of UW and HTK preservation solutions

AIM: To investigate whether amifostine contributes to the antioxidant and cytoprotective effects of histidine-tryptophan-ketoglutarate (HTK) and University of Wisconsin (UW) preservation solutions.

METHODS: Forty-eight Sprague Dawley male rats were equally divided into six groups: (1) ringer Lactate (RL) group; (2) RL + amifostine (RL + A) group; (3) HTK group; (4) HTK + A group; (5) UW group; and (6) UW + A group. Rats in the RL + A, HTK + A and UW + A groups were administered amifostine intraperitoneally at a dose of 200 mg/kg prior to laparotomy. The RL group was perfused with RL into the portal vein. The RL + A group were perfused with RL into the portal vein after amifostine administration. The HTK group received an HTK perfusion while the HTK + A group received an HTK perfusion after administration of amifostine. The UW group received a perfusion of UW, while the UW + A group received a UW perfusion after amifostine administration. Liver biopsy was performed to investigate histopathological, immunochemical [transferase mediated dUTP nick end labeling (TUNEL), inducible nitric oxide syntetase (iNOS)] and ultrastructural alterations. Biochemical alterations were determined by examining levels of alanine aminotransferase, alkaline phosphatase and nitric oxide in the perfusion fluid.

RESULTS: Pathological sinusoidal dilatation and centrilobular hydropic alteration were significantly lower in the groups that received amifostine prior to preservation solution perfusion. Although the best results were obtained in the UW + A group, we did not observe a statistically significant difference between the UW + A and HTK + A groups. iNOS grades were significantly lower in the amifostine groups 12 h after treatment. When the amifostine groups were compared against each other, the iNOS grades obtained from the UW + A and HTK + A groups were similar while the RL + A group had a much poorer score. TUNEL assays demonstrated a lower apoptosis ratio in the amifostine groups than in the non-amifostine groups 12 h after treatment. No statistically significant difference was observed between the UW + A and HTK + A groups for apoptosis. Cellular ultrastructure was best preserved in the UW + A and HTK + A groups.

CONCLUSION: Here, we show that preoperative administration of a single dose of amifostine is sufficient to minimize the preservation damage in hepatic cells.

Involvement of epigenetics and microRNA-29b in the urethane induced inception and establishment of mouse lung tumors

Epigenetic changes are correlated with tumor development showing aberrations in DNA methylation and histone modifications. To find the early changes, we evaluated the epigenetic events from early to late stage of the urethane induced lung tumor development in mouse model and tried to correlate the molecular events with the progression of tumor. We addressed the hypothesis by examining the tumor development, status of DNMTs, HDACs and MBDs, DNA methylation and expression of microRNA-29b during 1 to 36 weeks after urethane exposure that included the period before and after the tumor appearance. Tumors did not appear after 1 or 4 weeks but well defined tumors appeared after 12 weeks and larger tumors appeared at 36 weeks which was prevented by IP6. DNMT1, DNMT3a and DNMT3b were upregulated after urethane exposure at the time of no tumor till the tumor developed and showed its upregulated functional activity. DNMTs are shown to be the targets of microRNA-29b and we showed that microRNA-29b was downregulated in the line of DNMT upregulation. HDAC, the histone modifier, also showed progressive upregulation. Periodic increase in methyl binding proteins, MBD2, supported the expression of gene silencing pathways in terms of the downregulation of tumor suppressor genes, p16 and MLH1. All these molecular alterations were protected in the presence of IP6. Our results showed that the key steps of epigenetics, DNMTs, mir29b, and HDAC1, are altered both before and after the development of tumors.

Inositol hexaphosphate inhibits tumor growth, vascularity, and metabolism in TRAMP mice: a multiparametric magnetic resonance study

Herein, employing anatomical and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI), we evaluated noninvasively, the in vivo, chemopreventive efficacy of inositol hexaphosphate (IP6), a major constituent of high-fiber diets, against prostate tumor growth and progression in transgenic adenocarcinoma of the mouse prostate (TRAMP) model. Male TRAMP mice, beginning at 4 weeks of age, were fed with 1%, 2%, or 4% (w/v) IP6 in drinking water or only drinking water till 28 weeks of age and monitored using MRI over the course of study. Longitudinal assessment of prostate volumes by conventional MRI and tumor vascularity by gadolinium-based DCE-MRI showed a profound reduction in tumor size, partly due to antiangiogenic effects by IP6 treatment. As potential mechanisms of IP6 efficacy, decrease in the expression of glucose transporter GLUT-4 protein together with an increase in levels of phospho-AMP-activated kinase (AMPK(Th172)) were observed in prostate tissues of mice from IP6 fed-groups, suggesting that IP6 is interfering with the metabolic events occurring in TRAMP prostate. Investigative metabolomics study using quantitative high-resolution (1)H-NMR on prostate tissue extracts showed that IP6 significantly decreased glucose metabolism and membrane phospholipid synthesis, in addition to causing an increase in myoinositol levels in the prostate. Together, these findings show that oral IP6 supplement blocks growth and angiogenesis of prostate cancer in the TRAMP model in conjunction with metabolic events involved in tumor sustenance. This results in energy deprivation within the tumor, suggesting a practical and translational potential of IP6 treatment in suppressing growth and progression of prostate cancer in humans.

Involvement of STAT3, NF-κB and associated downstream molecules before and after the onset of urethane induced lung tumors in mouse

Here we have shown the alteration of transcription factors STAT3, NF-κB and downstream associated molecules much before the appearance of lung tumor and their response to antitumor agent, inositol hexaphosphate. Histological examination revealed the pathophysiology of the lung tissues and the onset or progression of tumor from 4 or 9 to 24 weeks in terms of tumor volume and the number. Over expression of NF-κB (p50/Rel A), COX-2, STAT3, pSTAT3 (Tyr 705), IL-6 and cyclin D1 also progressed from the time of no tumor to the time of tumor appearance and was reduced in mice drinking 2%IP6. We suggest that the alterations of STAT3, NF-κB and downstream associated molecules are critical in the development of lung tumors and can be exploited as possible mechanisms after the exposure. Status of these altered genes before the tumor development suggests their possible use as targets for the tumor control in the predisposed conditions.

The effect of inositol hexaphosphate on the expression of selected metalloproteinases and their tissue inhibitors in IL-1β-stimulated colon cancer cells

INTRODUCTION

Matrix metalloproteinases (MMPs) have repeatedly been shown to play a very active role in extracellular matrix degradation associated with tumor invasion and metastasis. Tissue inhibitors of MMPs (TIMPs) are well-known for their ability to inhibit MMP activity thereby inhibiting malignant progression. Inositol hexaphosphate (IP6 phytic acid) has been recognized to have both preventive and therapeutic effects against various cancers including that of colon. In in vitro studies, IP6 has been demonstrated to inhibit cancer cell adhesion and migration. In the present study, the effect of IP6 on the expression of MMP and TIMP genes was evaluated in unstimulated and IL-1β-stimulated colon cancer cell line Caco-2.

MATERIALS AND METHODS

Real-time QRT-PCR was used to validate the transcription level of selected MMP and TIMP genes in Caco-2 cells after treatment with 1 ng/ml of IL-1β, 2.5 mM of IP6, and both for 6, 12, and 24 h.

RESULTS

Stimulation of cells with IL-1β only resulted in an overexpression of MMP and their TIMP mRNAs. A significant decrease in MMP-13, MMP-3, MMP-2, and TIMP-1 basal expression was achieved by IP6. IP6 was also an efficient downregulator of MMP-1, MMP-9, and TIMP-2 genes transcription stimulated by IL-1β in 6 h lasting culture. After 12 h, IL-1β-induced MMP-2 mRNA expression was significantly reduced by IP6.

CONCLUSION

Proinflammatory cytokine IL-1β upregulates MMP and TIMP mRNAs expression in colon cancer epithelial cells Caco-2. IP6 (2.5 mM) influences constitutive expression of both MMP and TIMP genes and downregulates IL-1β stimulated transcription of some of these genes. IP6 exerts its anti-metastatic activity through modulation of MMP and TIMP genes expression to prevent cancer cell migration and invasion.

Pharmacokinetics and tissue distribution of inositol hexaphosphate in C.B17 SCID mice bearing human breast cancer xenografts

Inositol hexaphosphate (IP(6)) is effective in preclinical cancer prevention and chemotherapy. In addition to cancer, IP(6) has many other beneficial effects for human health, such as reduction in risk of developing cardiovascular disease and diabetes and inhibition of kidney stone formation. Studies presented here describe the pharmacokinetics, tissue distribution, and metabolism of IP(6) following intravenous (IV) or per os (PO) administration to mice. SCID mice bearing MDA-MB-231 xenografts were treated with 20 mg/kg IP(6) (3 μCi per mouse [(14)C]-uniformly ring-labeled IP(6)) and euthanized at various times after IP(6) treatment. Plasma and tissues were analyzed for [(14)C]-IP(6) and metabolites by high-performance liquid chromatography with radioactivity detection. Following IV administration of IP(6), plasma IP(6) concentrations peaked at 5 minutes and were detectable until 45 minutes. Liver IP(6) concentrations were more than 10-fold higher than plasma concentrations, whereas other normal tissue concentrations were similar to plasma. Only inositol was detected in xenografts. After PO administration, IP(6) was detected in liver; but only inositol was detectable in other tissues. After both IV and PO administration, exogenous IP(6) was rapidly dephosphorylated to inositol; however, alterations in endogenous IPs were not examined.

Novel inhibitors of AKT: assessment of a different approach targeting the pleckstrin homology domain

Protein kinase B/AKT plays a central role in cancer. The serine/threonine kinase is overexpressed or constitutively active in many cancers and has been validated as a therapeutic target for cancer treatment. However, targeting the kinase activity has revealed itself to be a challenge due to non-selectivity of the compounds towards other kinases. This review summarizes other approaches scientists have developed to inhibit the activity and function of AKT. They consist in targeting the pleckstrin homology (PH) domain of AKT. Indeed, upon the generation of 3-phosphorylated phosphatidylinositol phosphates (PI3Ps) by PI3-kinase (PI3K), AKT translocates from the cytosol to the plasma membrane and binds to the PI3Ps via its PH domain. Thus, several analogs of PI3Ps (PI Analogs or PIAs), alkylphospholipids (APLs), such as edelfosine or inositol phophates (IPs) have been described that inhibit the binding of the PH domain to PI3Ps. Recent allostertic inhibitors and small molecules that do not bind the kinase domain but affect the kinase activity of AKT, presumably by interacting with the PH domain, have been also identified. Finally, several drug screening studies spawned novel chemical scaffolds that bind the PH domain of AKT. Together, these approaches have been more or less sucessfull in vitro and to some extent translated in preclinical studies. Several of these new AKT PH domain inhibitors exhibit promising anti-tumor activity in mouse models and some of them show synergy with ionizing radiation and chemotherapy. Early clinical trials have started and results will attest to the validity and efficacy of such approaches in the near future.

Lobe-specific lineages of carcinogenesis in the transgenic adenocarcinoma of mouse prostate and their responses to chemopreventive selenium

BACKGROUND

The transgenic adenocarcinoma of mouse prostate (TRAMP) model is by far the most practical transgenic model for preclinical prostate cancer chemoprevention studies. It is critical to characterize the prostate lobe-specificity of lesion lineages to consolidate the advantages of this model and minimize its limitations for chemoprevention studies.

METHODS

We dissected dorsolateral (DLP), ventral (VP), and anterior prostate (AP) lobes, and macroscopic tumors from 90 male C57BL/6J TRAMP mice at 22-24 weeks of age (WOA) and analyzed lesions by histological, biochemical and proteomic approaches. To determine whether methylseleninic acid (MSeA) led to a deletion of initiated cells, we gave oral MSeA to TRAMP mice from 5 to 23 WOA or from 5 to 15 WOA and analyzed lesions at 23 WOA.

RESULTS

All tumors (n = 18) were T-antigen(+), synaptophysin (SYP)(+), androgen-receptor(-), and E-cadherin(-) poorly differentiated neuroendocrine carcinomas (NE-Ca). They were traceable most frequently to VP (66.7%) and rarely to DLP (11.1%) and AP (5.6%) with an estimated life-time incidence of 1 out of 3 mice. In DLP, epithelial lesions ranged from mild-to-severe atypical hyperplasia, with T-antigen(+), SYP(-), androgen-receptor(+), and E-cadherin(+). Proteomic profiling revealed many molecular differences between VP and DLP. In MSeA experiment, 6 out of 19 (31.5%) mice developed NE-Ca in the control group, only 2 in each MSeA group of 17-18 mice (11.1-11.8%) bore a detectable NE-Ca.

CONCLUSION

The C57BL/6J TRAMP mouse represents at least two lineages of prostate carcinogenesis. Chemoprevention studies should incorporate this knowledge for efficacy assessment and molecular target validations.

Melatonin, a novel Sirt1 inhibitor, imparts antiproliferative effects against prostate cancer in vitro in culture and in vivo in TRAMP model

We recently demonstrated that Sirt1, a NAD(+) -dependent histone deacetylase, was overexpressed in prostate cancer (PCa) and its inhibition resulted in a significant antiproliferative response in human PCa cells. Studies have suggested a link between Sirt1 and circadian rhythms, the disruption of which has been linked to cancer. Interestingly, a decreased production of the pineal melatonin has been shown to deregulate the circadian rhythm machinery and increase cancer risk. Furthermore, disruption in melatonin production and circadian rhythmicity has been associated with aging. Here, we challenged our hypothesis that melatonin will impart antiproliferative response against PCa via inhibiting Sirt1. We demonstrated that melatonin significantly inhibited Sirt1 protein and activity in vitro in multiple human PCa cell lines, and melatonin-mediated Sirt1 inhibition was accompanied with a significant decrease in the proliferative potential of PCa cells, but not of normal cells. Forced overexpression of Sirt1 partially rescued the PCa cells from melatonin's antiproliferative effects, suggesting that Sirt1 is a direct target of melatonin. Employing transgenic adenocarcinoma of mouse prostate (TRAMP) mice, we also demonstrated that oral administration of melatonin, at human-achievable doses, significantly inhibited PCa tumorigenesis as shown by decreases in (i) prostate and genitourinary weight, (ii) serum insulin-like growth factor-1 (IGF-1)/IGF-binding protein-3 (IGFBP3) ratio, (iii) mRNA and protein levels of the proliferation markers (PCNA, Ki-67). This anti-PCa response was accompanied with a significant decrease in Sirt1 in TRAMP prostate. Our data identified melatonin as a novel inhibitor of Sirt1 and suggest that melatonin can inhibit PCa growth via Sirt1 inhibition.

Changes in cellular levels of inositol polyphosphates during apoptosis

Accumulations of higher inositol polyphosphates, diphosphoinositol polyphosphates or pyrophosphates, have been implicated to mediate cellular apoptosis. Whether cellular levels of lower inositol phosphates (lower than inositol hexakisphosphates) change during apoptosis is not known, although these inositol phosphates are known to play crucial roles in a number of cellular signaling processes including calcium mobilization. Therefore, in this study, we have examined changes in cellular levels of inositol phosphates following metabolic labeling of these compounds by [(3)H]myo-inositol and induction of apoptosis. The levels of inositol mono- and bis-phosphates were increased, whereas the levels of inositol tris- and tetrakis-phosphates decreased significantly with an increasing rate of apoptosis induced by etoposide in a dose-dependent manner. NaF treatment, which increased the rate of apoptosis in a time- and dose-dependent manner, also increased the levels of inositol mono- and bis-phosphates and drastically reduced the levels of inositol tris- and tetrakis-phosphates. Prior treatment with antimycin A, a strategy used to reverse the NaF-induced accumulations of higher InsPs, partially reduced the effects of NaF on apoptosis as well as the levels of lower InsPs. Taken together, our results suggest that cellular levels of lower InsPs are altered during apoptosis.

The low phytic acid1-241 (lpa1-241) maize mutation alters the accumulation of anthocyanin pigment in the kernel

The lpa1 mutations in maize are caused by lesions in the ZmMRP4 (multidrug resistance-associated proteins 4) gene. In previous studies (Raboy et al. in Plant Physiol 124:355-368, 2000; Pilu et al. in Theor Appl Genet 107:980-987, 2003a; Shi et al. Nat Biotechnol 25:930-937, 2007), several mutations have been isolated in this locus causing a reduction of phytic acid (myo-inositol-1,2,3,4,5,6-hexakisphosphate, or InsP(6)) content and an equivalent increasing of free phosphate. In particular, the lpa1-241 mutation causes a reduction of up to 90% of phytic acid, associated with strong pleiotropic effects on the whole plant. In this work, we show, for the first time to our knowledge, an interaction between the accumulation of anthocyanin pigments in the kernel and the lpa mutations. In fact the lpa1-241 mutant accumulates a higher level of anthocyanins as compared to wild type either in the embryo (about 3.8-fold) or in the aleurone layer (about 0.3-fold) in a genotype able to accumulate anthocyanin. Furthermore, we demonstrate that these pigments are mislocalised in the cytoplasm, conferring a blue pigmentation of the scutellum, because of the neutral/basic pH of this cellular compartment. As a matter of fact, the propionate treatment, causing a specific acidification of the cytoplasm, restored the red pigmentation of the scutellum in the mutant and expression analysis showed a reduction of ZmMRP3 anthocyanins' transporter gene expression. On the whole, these data strongly suggest a possible interaction between the lpa mutation and anthocyanin accumulation and compartmentalisation in the kernel.

Efficacy of IP6 + inositol in the treatment of breast cancer patients receiving chemotherapy: prospective, randomized, pilot clinical study

Background

Prospective, randomized, pilot clinical study was conducted to evaluate the beneficial effects of inositol hexaphosphate (IP₆) + Inositol in breast cancer patients treated with adjuvant therapy.

Patients and methods

Patients with invasive ductal breast cancer where polychemotherapy was indicated were monitored in the period from 2005-2007. Fourteen patients in the same stage of ductal invasive breast cancer were involved in the study, divided in two randomized groups. One group was subjected to take IP₆ + Inositol while the other group was taking placebo. In both groups of patients the same laboratory parameters were monitored. When the treatment was finished, all patients have filled questionnaires QLQ C30 and QLQ-BR23 to determine the quality of life.

Results

Patients receiving chemotherapy, along with IP₆ + Inositol did not have cytopenia, drop in leukocyte and platelet counts. Red blood cell counts and tumor markers were unaltered in both groups. However, patients who took IP₆ + Inositol had significantly better quality of life (p = 0.05) and functional status (p = 0.0003) and were able to perform their daily activities.

Conclusion

IP₆ + Inositol as an adjunctive therapy is valuable help in ameliorating the side effects and preserving quality of life among the patients treated with chemotherapy.

Effect of phytic acid on suicidal erythrocyte death

Phytic acid, an anticarcinogenic food component, stimulates apoptosis of tumor cells. Similar to apoptosis, human erythrocytes may undergo suicidal death or eryptosis, characterized by cell membrane scrambling and cell shrinkage. Triggers of eryptosis include energy depletion. Phytate intake could cause anemia, an effect attributed to iron complexation. The present experiments explored whether phytic acid influences eryptosis. Supernatant hemoglobin concentration was determined to reveal hemolysis, annexin V-binding in FACS analysis was utilized to identify erythrocytes with scrambled cell membrane, forward scatter in FACS analysis was taken as a measure of cell volume, and a luciferin-luciferase assay was employed to determine erythrocyte ATP content. As a result, phytic acid (>or=1 mM) did not lead to significant hemolysis, but significantly increased the percentage of annexin V-binding erythrocytes, significantly decreased forward scatter, and significantly decreased cellular ATP content. In conclusion, phytic acid stimulates suicidal human erythrocyte death, an effect paralleling its proapoptotic effect on nucleated cells.

Inositol hexaphosphate downregulates both constitutive and ligand-induced mitogenic and cell survival signaling, and causes caspase-mediated apoptotic death of human prostate carcinoma PC-3 cells

Constitutively active mitogenic and prosurvival signaling cascades due to aberrant expression and interaction of growth factors and their receptors are well documented in human prostate cancer (PCa). Epidermal growth factor (EGF) and insulin-like growth factor-1 (IGF-1) are potent mitogens that regulate proliferation and survival of PCa cells via autocrine and paracrine loops involving both mitogen-activated protein kinase (MAPK)- and Akt-mediated signaling. Accordingly, here we assessed the effect of inositol hexaphosphate (IP6) on constitutive and ligand (EGF and IGF-1)-induced biological responses and associated signaling cascades in advanced and androgen-independent human PCa PC-3 cells. Treatment of PC-3 cells with 2 mM IP6 strongly inhibited both growth and proliferation and decreased cell viability; similar effects were also observed in other human PCa DU145 and LNCaP cells. IP6 also caused a strong apoptotic death of PC-3 cells together with caspase 3 and PARP cleavage. Mechanistic studies showed that biological effects of IP6 were associated with inhibition of both constitutive and ligand-induced Akt phosphorylation together with a decrease in total Akt levels, but a differential inhibitory effect on MAPKs extra cellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal protein kinase (JNK1/2), and p38 under constitutive and ligand-activated conditions. Under similar condition, IP6 also inhibited AP-1 DNA-binding activity and decreased nuclear levels of both phospho and total c-Fos and c-Jun. Together, these findings for the first time establish IP6 efficacy in inhibiting aberrant EGF receptor (EGFR) or IGF-1 receptor (IGF-1R) pathway-mediated sustained growth promoting and survival signaling cascades in advanced and androgen-independent human PCa PC-3 cells, which might have translational implications in advanced human PCa control and management.

Inositol hexaphosphate suppresses growth and induces apoptosis in prostate carcinoma cells in culture and nude mouse xenograft: PI3K-Akt pathway as potential target

Constitutive activation of phosphoinositide 3-kinase (PI3K)-Akt pathway transmits growth-regulatory signals that play a central role in promoting survival, proliferation, and angiogenesis in human prostate cancer cells. Here, we assessed the efficacy of inositol hexaphosphate (IP6) against invasive human prostate cancer PC-3 and C4-2B cells and regulation of PI3K-Akt pathway. IP6 treatment of cells suppressed proliferation, induced apoptosis along with caspase-3 and poly(ADP-ribose) polymerase (PARP) cleavage, and inhibited constitutive activation of Akt and its upstream regulators PI3K, phosphoinositide-dependent kinase-1 and integrin-linked kinase-1 (ILK1). Downstream of Akt, IP6 inhibited the phosphorylation of glycogen synthase kinase-3alpha/beta at Ser(21/9) and consequently reduced cyclin D1 expression. Efficacy studies employing PC-3 tumor xenograft growth in nude mice showed that 2% (w/v) IP6 feeding in drinking water inhibits tumor growth and weight by 52% to 59% (P < 0.001). Immunohistochemical analysis of xenografts showed that IP6 significantly reduces the expression of molecules associated with cell survival/proliferation (ILK1, phosphorylated Akt, cyclin D1, and proliferating cell nuclear antigen) and angiogenesis (platelet endothelial cell adhesion molecule-1 or CD31, vascular endothelial growth factor, endothelial nitric oxide synthase, and hypoxia-inducible factor-1alpha) together with an increase in apoptotic markers (cleaved caspase-3 and PARP). These findings suggest that, by targeting the PI3K-ILK1-Akt pathway, IP6 suppresses cell survival, proliferation, and angiogenesis but induces death in prostate cancer cells, which might have translational potential in preventing and controlling the growth of advanced and aggressive prostate cancer for which conventional chemotherapy is not effective.

Retinoid metabolism and ALDH1A2 (RALDH2) expression are altered in the transgenic adenocarcinoma mouse prostate model

Retinoids, which include vitamin A (retinol) and metabolites such as retinoic acid, can inhibit tumor growth and reverse carcinogenesis in animal models of prostate cancer. We analyzed retinoid signaling and metabolism in the TRAMP (transgenic adenocarcinoma mouse prostate) model. We detected increased retinol and retinyl esters in prostates pooled from 24 to 36 week TRAMP transgenic positive mice compared to nontransgenic littermates by HPLC. We used quantitative RT-PCR to measure transcripts for genes involved in retinoid signaling and metabolism, including ALDH1A1, ALDH1A2, ALDH1A3, CYP26A1, LRAT, and RARbeta(2), in prostate tissue from TRAMP positive (+) and age-matched littermate control mice ranging from 18 to 36 weeks. Transcript levels of ALDH1A1, a putative stem cell marker, were decreased in ventral and lateral lobes of prostates from TRAMP mice compared to age-matched, nontransgenic mice. ALDH1A2 (RALDH2) mRNA levels in dorsal and anterior lobes of TRAMP+ mice were lower than in age-matched (24 week) nontransgenic mice. We detected lower RARbeta(2) mRNA levels in dorsal prostate lobes of 36 week TRAMP mice relative to nontransgenic mice. We detected high levels of ALDH1A2 protein in the cytoplasm and nucleus in nontransgenic murine prostate paraffin sections, and lower ALDH1A2 protein levels in all prostate lobes of TRAMP mice compared to nontransgenic mice by immunohistochemistry. We also detected much lower cytoplasmic ALDH1A2 protein levels in all human prostate cancer paraffin sections stained (19 total) relative to normal human prostate tissue on the same sections. Our data indicate that this reduction in ALDH1A2 protein is an early event in human prostate cancer.

Methyl-selenium compounds inhibit prostate carcinogenesis in the transgenic adenocarcinoma of mouse prostate model with survival benefit

Chemoprevention of prostate cancer by second-generation selenium compounds in reference to selenomethionine holds strong promise to deal with the disease at the root. Here we used the transgenic adenocarcinoma mouse prostate (TRAMP) model to establish the efficacy of methylseleninic acid (MSeA) and methylselenocysteine (MSeC) against prostate carcinogenesis and to characterize potential mechanisms. Eight-week-old male TRAMP mice (C57B/6 background) were given a daily oral dose of water, MSeA, or MSeC at 3 mg Se/kg body weight and were euthanized at either 18 or 26 weeks of age. By 18 weeks of age, the genitourinary tract and dorsolateral prostate weights for the MSeA- and MSeC-treated groups were lower than for the control (P < 0.01). At 26 weeks, 4 of 10 control mice had genitourinary weight >2 g, and only 1 of 10 in each of the Se groups did. The efficacy was accompanied by delayed lesion progression, increased apoptosis, and decreased proliferation without appreciable changes of T-antigen expression in the dorsolateral prostate of Se-treated mice and decreased serum insulin-like growth factor I when compared with control mice. In another experiment, giving MSeA to TRAMP mice from 10 or 16 weeks of age increased their survival to 50 weeks of age, and delayed the death due to synaptophysin-positive neuroendocrine carcinomas and synaptophysin-negative prostate lesions and seminal vesicle hypertrophy. Wild-type mice receiving MSeA from 10 weeks did not exhibit decreased body weight or genitourinary weight or increased serum alanine aminotransferase compared with the control mice. Therefore, these selenium compounds may effectively inhibit this model of prostate cancer carcinogenesis.

Effect of inositol hexaphosphate on the development of UVB-induced skin tumors in SKH1 hairless mice

Inositol hexaphosphate (IP6) is a naturally occurring polyphosphorylated carbohydrate that is abundant in many plants and in various high-fiber foods, such as cereals and legumes. IP6 has a striking, broad-spectrum anticancer activity in various in vitro and animal models, in which it interferes with key pathways in malignancy to inhibit cell proliferation, cell-cycle progression, metastasis, invasion, and angiogenesis and to induce apoptosis. In this study, we investigated the protective effects of IP6 in drinking water on the incidence of UVB-induced skin cancer in the SKH1 (Crl: SKH1-hr) mouse model. One group of 15 mice received 2% IP6 in drinking water and UVB exposure, and the other group (n = 15) received UVB exposure only. All mice in both groups were fed an IP6-deficient diet (AIN 76A). The treatment group started receiving 2% IP6 in the drinking water 3 d before irradiation. Mice were irradiated 3 times each week, starting at a dose of 1.5 kJ/m2, with weekly increases in increments of 1.5 kJ/m2 to a final dose of 7.5 kJ/m2. Tumor formation was monitored until the week 31. IP6 in drinking water significantly decreased tumor incidence by 5-fold and tumor multiplicity by 4-fold. These results show that IP6 has an antiphotocarcinogenic effect and can protect against UVB-induced tumor formation.

Role of inositol polyphosphates in programmed cell death

The role of inositol polyphosphates (InsPs) in the mediation of cellular apoptosis was investigated in mouse MC3T3 osteoblastic cell line. Extracellular administration of InsP(4), InsP(5), and InsP(6) increased apoptosis in a dose-dependent manner. InsP(6) was more potent than InsP(5) and InsP(4) in promoting apoptosis. Inositol hexasulfate (InsS(6)), a structural analog of InsP(6), was used to determine specificity of InsP(6)-induced apoptosis as measured by acridine orange/ethidium bromide, flow cytometry, and DNA degradation. In order to study the effects of endogenous InsPs on apoptosis, we used NaF and antimycin A as treatment agents to manipulate intracellular levels of InsPs. NaF is known to increase levels of higher InsPs by inhibiting InsPs phosphatases, a process that is reversed by antimycin A because InsPs kinases are inhibited as a result of depletion of cellular ATP pools. Apoptosis was induced in MC3T3 cells in a NaF dose- and time-dependent manner. Approximately 50% apoptosis was observed at 1 mM NaF in 8 h. Prior treatment with 10 microM antimycin A for 30 min significantly reduced the NaF-induced apoptosis as compared with its control. Additionally, we measured changes in AKT phosphorylation, cleavage of caspase-3 and caspase-9, and release of cytochrome C from mitochondria into cytosol. These changes coincided with total cellular InsPs under similar conditions. The data indicated that NaF-induced changes in apoptotic markers could be due to an increased endogenous InsPs that were partially reversed by antimycin A treatment.

p21/Cip1 and p27/Kip1 Are essential molecular targets of inositol hexaphosphate for its antitumor efficacy against prostate cancer

Inositol hexaphosphate (IP6) causes G(1) arrest and increases cyclin-dependent kinase inhibitors p21/Cip1 and p27/Kip1 protein levels in human prostate cancer (PCa) DU145 cells lacking functional p53. However, whether cyclin-dependent kinase inhibitor I induction by IP6 plays any role in its antitumor efficacy is unknown. Herein, we observed that either p21 or p27 knockdown by small interfering RNA has no considerable effect on IP6-induced G(1) arrest, growth inhibition, and death in DU145 cells; however, the simultaneous knockdown of both p21 and p27 reversed the effects of IP6. To further confirm these findings both in vitro and in vivo, we generated DU145 cell variants with knockdown levels of p21 (DU-p21), p27 (DU-p27), or both (DU-p21+p27) via retroviral transduction of respective short hairpin RNAs. Knocking down p21 or p27 individually did not alter IP6-caused cell growth inhibition and G(1) arrest; however, their simultaneous ablation completely reversed the effects of IP6. In tumor xenograft studies, IP6 (2% w/v, in drinking water) caused a comparable reduction in tumor volume (40-46%) and tumor cell proliferation (26-28%) in DU-EV (control), DU-p21, and DU-p27 tumors but lost most of its effect in DU-p21+p27 tumors. IP6-caused apoptosis also occurred in a Cip/Kip-dependent manner because DU-p21+p27 cells were completely resistant to IP6-induced apoptosis both in cell culture and xenograft. Together, these results provide evidence, for the first time, of the critical role of p21 and p27 in mediating the anticancer efficacy of IP6, and suggest their redundant role in the antiproliferative and proapoptotic effects of IP6 in p53-lacking human PCa cells, both in vitro and in vivo.