Randomized phase II trial of sulindac, atorvastatin, and prebiotic dietary fiber for colorectal cancer chemoprevention

Colorectal cancer and inulin supplementation: the good, the bad, and the unhelpful

The prebiotic inulin has been vaunted for its potential to reduce the risk of colorectal cancer. Inulin fermentation resulting in the production of short-chain fatty acids, primarily butyrate, has been reported to be associated with properties that are beneficial for gut health and has led to an increased consumption of inulin in the Western population through processed food and over-the-counter dietary supplements. However, in clinical trials, there is limited evidence of the efficacy of inulin in preventing colorectal cancer. Moreover, recent data suggest that improper inulin consumption may even be harmful for gastro-intestinal health under certain circumstances. The main objective of this review is to provide insight into the beneficial and potentially detrimental effects of inulin supplementation in the context of colorectal cancer prevention and enhancement of treatment efficacy.

Inulin-based formulations as an emerging therapeutic strategy for cancer: A comprehensive review

Cancer stands as the second leading cause of death in the United States (US). Most chemotherapeutic agents exhibit severe adverse effects that are attributed to exposure of drugs to off-target tissues, posing a significant challenge in cancer therapy management. In recent years, inulin, a naturally occurring prebiotic fiber has gained substantial attention for its potential in cancer treatment owing to its multitudinous health values. Its distinctive structure, stability, and nutritional properties position it as an effective adjuvant and carrier for drug delivery in cancer therapy. To address some of the above unmet clinical issues, this review summarizes the recent efforts towards the development of inulin-based nanomaterials and nanocomposites for healthcare applications with special emphasis on the multifunctional role of inulin in cancer therapy as a synergist, signaling molecule, immunomodulatory and anticarcinogenic molecule. Furthermore, the review provides a concise overview of ongoing clinical trials and observational studies associated with inulin-based therapy. In conclusion, the current review offers insights on the significant role of inulin interventions in exploring its potential as a therapeutic agent to treat cancer.

Efficacy and safety of probiotics, prebiotics, and synbiotics for the prevention of colorectal cancer and precancerous lesion in high-risk populations: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

Colorectal cancer (CRC) is highly prevalent worldwide and is a leading cause of cancer-related death. Probiotics, prebiotics, and synbiotics have recently attracted attention as preventive measures against colorectal neoplasms. We aimed to analyze the findings of randomized controlled trials (RCTs) on the effects of probiotics, prebiotics, and synbiotics in patients at a high risk of CRC, outlining the challenges and future prospects of using probiotics to prevent colorectal tumors and providing evidence for clinical physicians in particular.

METHODS

PubMed, EMBASE, and the Cochrane Library databases were searched for relevant studies published up to January 7, 2022. RCTs conducted on populations with a high risk of CRC who received probiotics, prebiotics or synbiotics in comparison with placebo, candidate agent or no treatment were included. The primary outcome was the incidence or recurrence of any colorectal neoplasms. Additional outcomes included their effects on the diversity of gut microbiota and relevant inflammatory biomarkers. Safety outcomes were also analyzed. Two authors independently screened and selected studies based on pre-specified eligible criteria, performed data extraction and risk-of-bias assessment independently.

RESULTS

Nine RCTs were included in the systematic review and meta-analysis. Probiotic supplementation significantly reduced adenoma incidence, but no significant benefit was observed in CRC incidence. Additionally, probiotics modulated gut microbiota and inflammatory biomarkers.

CONCLUSION

Probiotics may have beneficial effects in the prevention of CRC. More RCTs with larger sample sizes are warranted to further confirm these findings.

Inulin impacts tumorigenesis promotion by colibactin-producing Escherichia coli in ApcMin/+ mice

Introduction

The prebiotic inulin has previously shown both protective and tumor-promoting effects in colorectal cancer (CRC). These inconsistencies may be due to the gut microbial composition as several bacteria have been associated with CRC. Specifically, polyketide synthase-positive (pks+) Escherichia coli promotes carcinogenesis and facilitates CRC progression through the production of colibactin, a genotoxin that induces double-strand DNA breaks (DSBs). We investigated whether colibactin-producing Escherichia coli changed the protection conferred by inulin against tumor growth and progression using the Apc^Min/+ mouse model of CRC.

Methods

Mice received a 2% dextran sodium sulfate (DSS) solution followed by oral gavage with the murine pks + E. coli strain NC101 (EcNC101) and were fed a diet supplemented with 10% cellulose as control or 10% inulin for 4 weeks.

Results

Inulin supplementation led to increase EcNC101 colonization compared to mice receiving the control diet. The increased colonization of EcNC101 resulted in more DSBs, tumor burden, and tumor progression in Apc^Min/+ mice. The tumorigenic effect of EcN101 in Apc^Min/+ mice mediated by inulin was dependent on colibactin production. Pasteurized E. coli Nissle 1917 (EcN), a probiotic, suppressed the inulin-driven EcNC101 expansion and impacted tumor progression.

Discussion

Our results suggest that the presence of pks + E. coli influences the outcome of inulin supplementation in CRC and that microbiota-targeted interventions may mitigate this effect. Given the prevalence of pks + E. coli in both healthy and CRC populations and the importance of a fiber-rich diet, inulin supplementation in individuals colonized with pks + bacteria should be considered with caution.

Modulation of Gut Microbiota to Enhance Effect of Checkpoint Inhibitor Immunotherapy

Accumulating evidence demonstrated the crucial role of gut microbiota in many human diseases, including cancer. Checkpoint inhibitor therapy has emerged as a novel treatment and has been clinically accepted as a major therapeutic strategy for cancer. Gut microbiota is related to cancer and the effect of immune checkpoint inhibitors (ICIs), and supplement with specific bacterial species can restore or enhance the responses to the ICIs. Namely, specified bacteria can serve as the biomarkers for distinguishing the patient who will respond to ICIs and determine the effectiveness of ICIs, as well as predicting the efficacy of checkpoint inhibitor immunotherapy. Regardless of the significant findings, the relationship between gut microbiota and the effect of ICIs treatment needs a more thorough understanding to provide more effective therapeutic plans and reduce treatment complication. In this review, we summarized the role of gut microbiota played in immune system and cancer. We mainly focus on the relationship between gut microbiota and the checkpoint inhibitor immunotherapy.

Dysplastic Aberrant Crypt Foci: Biomarkers of Early Colorectal Neoplasia and Response to Preventive Intervention

The discovery of aberrant crypt foci (ACF) more than three decades ago not only enhanced our understanding of how colorectal tumors form, but provided new opportunities to detect lesions prior to adenoma development and intervene in the colorectal carcinogenesis process even earlier. Because not all ACF progress to neoplasia, it is important to stratify these lesions based on the presence of dysplasia and establish early detection methods and interventions that specifically target dysplastic ACF (microadenomas). Significant progress has been made in characterizing the morphology and genetics of dysplastic ACF in both preclinical models and humans. Image-based methods have been established and new techniques that utilize bioactivatable probes and capture histologic abnormalities in vivo are emerging for lesion detection. Successful identification of agents that target dysplastic ACF holds great promise for intervening even earlier in the carcinogenesis process to maximize tumor inhibition. Future preclinical and clinical prevention studies should give significant attention to assessing the utility of dysplastic ACF as the earliest identifiable biomarker of colorectal neoplasia and response to therapy.See all articles in this Special Collection Honoring Paul F. Engstrom, MD, Champion of Cancer Prevention.

Randomized Phase II Trial of Polyphenon E versus Placebo in Patients at High Risk of Recurrent Colonic Neoplasia

Polyphenon E (Poly E) is a green tea polyphenol preparation whose most active component is epigallocatechin gallate (EGCG). We studied the cancer preventive efficacy and safety of Poly E in subjects with rectal aberrant crypt foci (ACF), which represent putative precursors of colorectal cancers. Eligible subjects had prior colorectal advanced adenomas or cancers, and had ≥5 rectal ACF at a preregistration chromoendoscopy. Subjects (N = 39) were randomized to 6 months of oral Poly E (780 mg EGCG) daily or placebo. Baseline characteristics were similar by treatment arm (all P >0.41); 32 of 39 (82%) subjects completed 6 months of treatment. The primary endpoint was percent reduction in rectal ACF at chromoendoscopy comparing before and after treatment. Among 32 subjects (15 Poly E, 17 placebo), percent change in rectal ACF number (baseline vs. 6 months) did not differ significantly between study arms (3.7% difference of means; P = 0.28); total ACF burden was also similar (-2.3% difference of means; P = 0.83). Adenoma recurrence rates at 6 months were similar by arm (P > 0.35). Total drug received did not differ significantly by study arm; 31 (79%) subjects received ≥70% of prescribed Poly E. Poly E was well tolerated and adverse events (AE) did not differ significantly by arm. One subject on placebo had two grade 3 AEs; one subject had grade 2 hepatic transaminase elevations attributed to treatment. In conclusion, Poly E for 6 months did not significantly reduce rectal ACF number relative to placebo. Poly E was well tolerated and without significant toxicity at the dose studied. PREVENTION RELEVANCE: We report a chemoprevention trial of polyphenon E in subjects at high risk of colorectal cancer. The results show that polyphenon E was well tolerated, but did not significantly reduce the number of rectal aberrant crypt foci, a surrogate endpoint biomarker of colorectal cancer.

Radiotherapy and the gut microbiome: facts and fiction

An ever-growing body of evidence has linked the gut microbiome with both the effectiveness and the toxicity of cancer therapies. Radiotherapy is an effective way to treat tumors, although large variations exist among patients in tumor radio-responsiveness and in the incidence and severity of radiotherapy-induced side effects. Relatively little is known about whether and how the microbiome regulates the response to radiotherapy. Gut microbiota may be an important player in modulating “hot” versus “cold” tumor microenvironment, ultimately affecting treatment efficacy. The interaction of the gut microbiome and radiotherapy is a bidirectional function, in that radiotherapy can disrupt the microbiome and those disruptions can influence the effectiveness of the anticancer treatments. Limited data have shown that interactions between the radiation and the microbiome can have positive effects on oncotherapy. On the other hand, exposure to ionizing radiation leads to changes in the gut microbiome that contribute to radiation enteropathy. The gut microbiome can influence radiation-induced gastrointestinal mucositis through two mechanisms including translocation and dysbiosis. We propose that the gut microbiome can be modified to maximize the response to treatment and minimize adverse effects through the use of personalized probiotics, prebiotics, or fecal microbial transplantation. 16S rRNA sequencing is the most commonly used approach to investigate distribution and diversity of gut microbiome between individuals though it only identifies bacteria level other than strain level. The functional gut microbiome can be studied using methods involving metagenomics, metatranscriptomics, metaproteomics, as well as metabolomics. Multiple ‘-omic’ approaches can be applied simultaneously to the same sample to obtain integrated results. That said, challenges and remaining unknowns in the future that persist at this time include the mechanisms by which the gut microbiome affects radiosensitivity, interactions between the gut microbiome and combination treatments, the role of the gut microbiome with regard to predictive and prognostic biomarkers, the need for multi “-omic” approach for in-depth exploration of functional changes and their effects on host-microbiome interactions, and interactions between gut microbiome, microbial metabolites and immune microenvironment.

Efficacy and safety profile of statins in patients with cancer: a systematic review of randomised controlled trials

PURPOSE

A growing body of preclinical and observational research suggests that statins have potential as a therapeutic strategy in patients with cancer. This systematic review of randomised controlled trials (RCTs) in patients with solid tumours aimed to determine the efficacy of statin therapy on mortality outcomes, their safety profile and the risk of bias of included studies.

METHODS

Full-text articles comparing statin therapy versus control in solid tumours and reporting mortality outcomes were identified from Medline and Embase from conception to February 2020. A systematic review with qualitative (primarily) and quantitative synthesis was conducted. This systematic review was prospectively registered (Prospero registration CRD42018116364).

RESULTS

Eleven trials of 2165 patients were included. Primary tumour sites investigated included lung, colorectal, gastro-oesophageal, pancreatic and liver. Most trials recruited patients with advanced malignancy and used sub-maximal statin doses for relatively short durations. Aside from one trial which demonstrated benefit with allocation to pravastatin 40 mg in hepatocellular carcinoma, the remaining ten trials did not demonstrate efficacy with statins. The pooled hazard ratio for all-cause mortality with allocation to pravastatin in patients with hepatocellular carcinoma in two trials was 0.69 (95% confidence interval CI 0.30-1.61). Study estimates were imprecise. There were no clinically important differences in statin-related adverse events between groups. Overall, included trials were deemed low risk of bias.

CONCLUSION

The trial evidence is not sufficiently robust to confirm or refute the efficacy and safety of statins in patients with solid malignant tumours. Study and patient characteristics may explain this uncertainty. The potential role of high-dose statins in adjuvant settings deserves further research.

Non-Digestible Carbohydrate and the Risk of Colorectal Neoplasia: A Systematic Review

Non-digestible carbohydrate (NDC) is a fiber that can be fermented into short chain fatty acids (SCFAs) in gut, represented by resistant starch (RS) and inulin. Colorectal cancer (CRC) is one of the most common malignant cancer. Pre-clinical studies have reported that NDC can produce SCFAs to protect the gut epithelium, which is associated with prevention of CRC, but this role in clinical trails is controversial. In this review, we discusses whether RS and inulin should be offered to cancer/precancerous patients or healthy subjects to decrease their risk of CRC. A multiple database search was conducted for studies published on RS/inulin supplementation as a chemopreventive method from 1989 to 2019. The meta-analysis showed the total SCFAs and butyrate concentrations (P = 0.84; P = 0.79), and excretions (P = 0.55; P = 0.63) in feces did not increase significantly after RS/inulin supplementation. Only two studies reported that RS/inulin inhibit the proliferation of large bowel epithelial, whereas 15 studies showed that it does not decrease the risk of neoplasia. RS/inulin restored the promotion of tumor risk factors in two studies and did not in four studies. Notably, the other four studies showed that RS increases pro-tumorigenesis mechanisms. The clinical evidences consistently show that RS/inulin is ineffective for preventing colorectal neoplasia.

Efficacy of Difluoromethylornithine and Aspirin for Treatment of Adenomas and Aberrant Crypt Foci in Patients with Prior Advanced Colorectal Neoplasms

Difluoromethylornithine (DFMO), an inhibitor of polyamine synthesis, was shown to act synergistically with a NSAID for chemoprevention of colorectal neoplasia. We determined the efficacy and safety of DFMO plus aspirin for prevention of colorectal adenomas and regression of rectal aberrant crypt foci (ACF) in patients with prior advanced adenomas or cancer. A double-blinded, placebo-controlled trial was performed in 104 subjects (age 46-83) randomized (1:1) to receive daily DFMO (500 mg orally) plus aspirin (325 mg) or matched placebos for one year. All polyps were removed at baseline. Adenoma number (primary endpoint) and rectal ACF (index cluster and total) were evaluated at a one year colonoscopy. ACF were identified by chromoendoscopy. Toxicity was monitored, including audiometry. Eighty-seven subjects were evaluable for adenomas or ACF modulation (n = 62). At one year of treatment, adenomas were detected in 16 (38.1%) subjects in the DFMO plus aspirin arm (n = 42) versus 18 (40.9%) in the placebo arm (n = 44; P = 0.790); advanced adenomas were similar (n = 3/arm). DFMO plus aspirin was associated with a statistically significant reduction in the median number of rectal ACF compared with placebo (P = 0.036). Total rectal ACF burden was also reduced in the treatment versus the placebo arm relative to baseline (74% vs. 45%, P = 0.020). No increase in adverse events, including ototoxicity, was observed in the treatment versus placebo arms. While adenoma recurrence was not significantly reduced by one year of DFMO plus aspirin, the drug combination significantly reduced rectal ACF number consistent with a chemopreventive effect.

Effect of inulin-type fructans in patients undergoing cancer treatments: A systematic review

Background and Objective

Current studies give us inconsistent results regarding the inulin consumption in cancer patients. The results of to-date studies are summarized in this systematic review.

Methods

Web of Science (Science citation index expanded), PubMed (Medline), Embase and CENTRAL Science direct, Google scholar, Scopus and Cochrane were searched. Cochrane Collaboration's 'Risk of Bias' tool was used to assess the quality of included articles.

Results

Our search yielded 2652 studies after the elimination of duplicates. Three randomized controlled trials (RCTs), reporting results from 197 patients, were eligible for inclusion in the present systematic review. Risk of bias in these studies was assessed as high and moderate.

Conclusion

The available evidence is inconclusive regarding the effect of inulin and oligofructose on cancer outcomes. Nonetheless, possible inulin positive effects including improved stool consistency after abdomen radiotherapy and increased stool butyrate content which is involved in controlling tumor cells proliferation and apoptosis should not be denied. Further research is needed in this area before strong conclusions can be drawn.

Chemoprevention of Colorectal Cancer by Dietary Compounds

Colorectal cancer is one of the leading causes of death, and the third most diagnosed type of cancer, worldwide. It is most common amongst men and women over 50 years old. Risk factors include smoking, alcohol, diet, physical inactivity, genetics, alterations in gut microbiota, and associated pathologies (diabetes, obesity, chronic inflammatory bowel diseases). This review will discuss, in detail, the chemopreventive properties of some dietary compounds (phenolic compounds, carotenoids, iridoids, nitrogen compounds, organosulfur compounds, phytosterols, essential oil compounds, polyunsaturated fatty acids and dietary fiber) against colorectal cancer. We present recent data, focusing on in vitro, laboratory animals and clinical trials with the previously mentioned compounds. The chemopreventive properties of the dietary compounds involve multiple molecular and biochemical mechanisms of action, such as inhibition of cell growth, inhibition of tumor initiation, inhibition of adhesion, migration and angiogenesis, apoptosis, interaction with gut microbiota, regulation of cellular signal transduction pathways and xenobiotic metabolizing enzymes, etc. Moreover, this review will also focus on the natural dietary compounds' bioavailability, their synergistic protective effect, as well as the association with conventional therapy. Dietary natural compounds play a major role in colorectal chemoprevention and continuous research in this field is needed.

Intestinal microbiota: a novel perspective in colorectal cancer biotherapeutics

It is believed that genetic factors, immune system dysfunction, chronic inflammation, and intestinal microbiota (IM) dysbiosis contribute to the pathogenesis of colorectal cancer (CRC). The beneficial role played by the direct regulation of IM in inflammatory bowel disease treatment is identified by the decreased growth of harmful bacteria and the increased production of anti-inflammatory factors. Interestingly, gut microbiota has been proven to inhibit tumor formation and progression in inflammation/carcinogen-induced CRC mouse models. Recently, evidence has indicated that IM is involved in the negative regulation of tumor immune response in tumor microenvironment, which then abolishes or accelerates anticancer immunotherapy in several tumor animals. In clinical trials, a benefit of IM-based CRC therapies in improving the intestinal immunity balance, epithelial barrier function, and quality of life has been reported. Meanwhile, specific microbiota signature can modulate host's sensitivity to chemo-/radiotherapy and the prognosis of CRC patients. In this review, we aim to 1) summarize the potential methods of IM-based therapeutics according to the recent results; 2) explore its roles and underlying mechanisms in combination with other therapies, especially in biotherapeutics; 3) discuss its safety, deficiency, and future perspectives.

Differential preventive activity of sulindac and atorvastatin in Apc+/Min-FCCCmice with or without colorectal adenomas

OBJECTIVE

The response of subjects to preventive intervention is heterogeneous. The goal of this study was to determine if the efficacy of a chemopreventive agent differs in non-tumour-bearing animals versus those with colorectal tumours. Sulindac and/or atorvastatin was administered to Apc^+/Min-FCCC mice with known tumour-bearing status at treatment initiation.

DESIGN

Male mice (6-8 weeks old) underwent colonoscopy and received control chow or chow with sulindac (300 ppm), atorvastatin (100 ppm) or sulindac/atorvastatin. Tissues were collected from mice treated for 14 weeks (histopathology) or 7 days (gene expression). Cell cycle analyses were performed on SW480 colon carcinoma cells treated with sulindac, atorvastatin or both.

RESULTS

The multiplicity of colorectal adenomas in untreated mice bearing tumours at baseline was 3.6-fold higher than that of mice that were tumour free at baseline (P=0.002). Atorvastatin completely inhibited the formation of microadenomas in mice that were tumour free at baseline (P=0.018) and altered the expression of genes associated with stem/progenitor cells. Treatment of tumour-bearing mice with sulindac/atorvastatin led to a 43% reduction in the multiplicity of colorectal adenomas versus untreated tumour-bearing mice (P=0.049). Sulindac/atorvastatin increased the expression of Hoxb13 and Rprm significantly, suggesting the importance of cell cycle regulation in tumour inhibition. Treatment of SW480 cells with sulindac/atorvastatin led to cell cycle arrest (G0/G1).

CONCLUSIONS

The tumour status of animals at treatment initiation dictates response to therapeutic intervention. Atorvastatin eliminated microadenomas in tumour-free mice. The tumour inhibition observed with Sul/Atorva in tumour-bearing mice was greater than that achieved with each agent.

Association between Nonsteroidal Anti-Inflammatory Drugs and Colorectal Cancer: A Population-Based Case-Control Study

Background: COX-2 overexpression may contribute to colorectal cancer occurrence. Aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce colorectal cancer recurrence, but the efficacy of primary prevention in Asian populations is still elusive. Thus, we examined the primary preventive efficacy of aspirin and NSAIDs on colorectal cancer incidence in Taiwan.Methods: A nested case-control study was conducted using the National Health Insurance Research Database (NHIRD) in Taiwan. We identified patients with diagnosis of colorectal cancer from 2005 to 2013 in the Registry of Catastrophic Illness Patient Database. We selected patients without colorectal cancer from the Longitudinal Health Insurance Database as the controls and matched them with cases. NSAID exposure was defined as at least two prescriptions 13 to 48 months prior to the index date. Conditional logistic regression models were performed to evaluate the association between NSAID use and colorectal cancer.Results: A total of 65,208 colorectal cancer cases and 65,208 matched controls were identified. Patients with aspirin use had a lower risk of colorectal cancer compared with nonusers [adjusted OR (AOR) = 0.94, 95% confidence interval (CI) = 0.90-0.99]. NSAID use was associated with lower incidence of colorectal cancer (AOR = 0.96; 95% CI = 0.92-1.00). When examining colon or rectal cancer, similar decreased risks were observed. Patients taking more cumulative days of NSAIDs use tended to experience a more protective effect on colorectal cancer, but no dose-response effects were noted.Conclusions: Aspirin and NSAIDs were associated with a reduced risk of colorectal cancer development among a study cohort in an Asian population.Impact: This study provided a possible chemoprevention for colorectal cancer in an Asian population. Cancer Epidemiol Biomarkers Prev; 27(7); 737-45. ©2018 AACR.

Statistical controversies in clinical research: Value of adverse events relatedness to study treatment: analyses of data from randomized double-blind placebo-controlled clinical trials

Background

Collection and reporting of adverse events (AEs) and their relatedness to study treatment, known commonly as attribution, in clinical trials is mandated by regulatory agencies (the National Cancer Institute and the Food and Drug Administration). Attribution is assigned by the treating physician using judgment based on various factors including patient's baseline status, disease history, and comorbidity as well as knowledge about the safety profile of the study treatments. We evaluate the patterns of AE attribution (unrelated, unlikely, possibly, probably, and definitely related to the treatment) in treatment, symptom intervention (cancer patients) and cancer prevention (participants at high risk for cancer) setting.

Materials and methods

Nine multicenter placebo-controlled trials (two treatment, two symptom intervention, and five cancer prevention) were analysed separately (2155 patients). Frequency and severity of AEs were summarized by arm. Attribution and percentage of repeated AEs whose attribution changed overtime were summarized for the placebo arms. Percentage of physician over- or under-reporting of AE relatedness was calculated for the treatment arms using the placebo arm as the reference.

Results

Across all trials and settings, a very high proportion of AEs reported as related to treatment were classified as possibly related, a significant proportion of AEs in the placebo arm were incorrectly reported as related to treatment, and clinician-reported attribution over-estimated the rate of AEs related to treatment. Fatigue, nausea, vomiting, diarrhea, constipation, and neurosensory were the common AEs that were over reported by clinician as related to treatment.

Conclusions

These analyses demonstrate that assigning causality to AE is a complex and difficult process that produces unreliable and subjective data. In randomized double-blind placebo-controlled trials where data are available to objectively assess relatedness of AE to treatment, attribution assignment should be eliminated.

Multicenter, Phase III, Randomized, Double-Blind, Placebo-Controlled Trial of Pravastatin Added to First-Line Standard Chemotherapy in Small-Cell Lung Cancer (LUNGSTAR)

Purpose Treating small-cell lung cancer (SCLC) remains a therapeutic challenge. Experimental studies show that statins exert additive effects with agents, such as cisplatin, to impair tumor growth, and observational studies suggest that statins combined with anticancer therapies delay relapse and prolong life in several cancer types. To our knowledge, we report the first large, randomized, placebo-controlled, double-blind trial of a statin with standard-of-care for patients with cancer, specifically SCLC. Patients and Methods Patients with confirmed SCLC (limited or extensive disease) and performance status 0 to 3 were randomly assigned to receive daily pravastatin 40 mg or placebo, combined with up to six cycles of etoposide plus cisplatin or carboplatin every 3 weeks, until disease progression or intolerable toxicity. Primary end point was overall survival (OS), and secondary end points were progression-free survival (PFS), response rate, and toxicity. Results Eight hundred forty-six patients from 91 United Kingdom hospitals were recruited. The median age of recruited patients was 64 years of age, 43% had limited disease, and 57% had extensive disease. There were 758 deaths and 787 PFS events. No benefit was found for pravastatin, either in all patients or in several subgroups. For pravastatin versus placebo, the 2-year OS rate was 13.2% (95% CI, 10.0 to 16.7) versus 14.1% (95% CI, 10.9 to 17.7), respectively, with a hazard ratio of 1.01 (95% CI, 0.88 to 1.16; P = .90. The median OS was 10.7 months v 10.6 months, respectively. The median PFS was 7.7 months v 7.3 months, respectively. The median OS (pravastatin v placebo) was 14.6 months in both groups for limited disease and 9.1 months versus 8.8 months, respectively, for extensive disease. Adverse events were similar between groups. Conclusion Pravastatin 40 mg combined with standard SCLC therapy, although safe, does not benefit patients. Our conclusions are the same as those found in all four much smaller, randomized, placebo-controlled trials specifically designed to evaluate statin therapy in patients with cancer.

Dietary fibre for the prevention of recurrent colorectal adenomas and carcinomas

BACKGROUND

This is an update of the Cochrane review published in 2002.Colorectal cancer (CRC) is a major cause of morbidity and mortality in industrialised countries. Experimental evidence has supported the hypothesis that dietary fibre may protect against the development of CRC, although epidemiologic data have been inconclusive.

OBJECTIVES

To assess the effect of dietary fibre on the recurrence of colorectal adenomatous polyps in people with a known history of adenomatous polyps and on the incidence of CRC compared to placebo. Further, to identify the reported incidence of adverse effects, such as abdominal pain or diarrhoea, that resulted from the fibre intervention.

SEARCH METHODS

We identified randomised controlled trials (RCTs) from Cochrane Colorectal Cancer's Specialised Register, CENTRAL, MEDLINE and Embase (search date, 4 April 2016). We also searched ClinicalTrials.gov and WHO International Trials Registry Platform on October 2016.

SELECTION CRITERIA

We included RCTs or quasi-RCTs. The population were those having a history of adenomatous polyps, but no previous history of CRC, and repeated visualisation of the colon/rectum after at least two-years' follow-up. Dietary fibre was the intervention. The primary outcomes were the number of participants with: 1. at least one adenoma, 2. more than one adenoma, 3. at least one adenoma greater than or equal to 1 cm, or 4. a new diagnosis of CRC. The secondary outcome was the number of adverse events.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data, assessed trial quality and resolved discrepancies by consensus. We used risk ratios (RR) and risk difference (RD) with 95% confidence intervals (CI) to measure the effect. If statistical significance was reached, we reported the number needed to treat for an additional beneficial outcome (NNTB) or harmful outcome (NNTH). We combined the study data using the fixed-effect model if it was clinically, methodologically, and statistically reasonable.

MAIN RESULTS

We included seven studies, of which five studies with 4798 participants provided data for analyses in this review. The mean ages of the participants ranged from 56 to 66 years. All participants had a history of adenomas, which had been removed to achieve a polyp-free colon at baseline. The interventions were wheat bran fibre, ispaghula husk, or a comprehensive dietary intervention with high fibre whole food sources alone or in combination. The comparators were low-fibre (2 to 3 g per day), placebo, or a regular diet. The combined data showed no statistically significant difference between the intervention and control groups for the number of participants with at least one adenoma (5 RCTs, n = 3641, RR 1.04, 95% CI 0.95 to 1.13, low-quality evidence), more than one adenoma (2 RCTs, n = 2542, RR 1.06, 95% CI 0.94 to 1.20, low-quality evidence), or at least one adenoma 1 cm or greater (4 RCTs, n = 3224, RR 0.99, 95% CI 0.82 to 1.20, low-quality evidence) at three to four years. The results on the number of participants diagnosed with colorectal cancer favoured the control group over the dietary fibre group (2 RCTS, n = 2794, RR 2.70, 95% CI 1.07 to 6.85, low-quality evidence). After 8 years of comprehensive dietary intervention, no statistically significant difference was found in the number of participants with at least one recurrent adenoma (1 RCT, n = 1905, RR 0.97, 95% CI 0.78 to 1.20), or with more than one adenoma (1 RCT, n = 1905, RR 0.89, 95% CI 0.64 to 1.24). More participants given ispaghula husk group had at least one recurrent adenoma than the control group (1 RCT, n = 376, RR 1.45, 95% CI 1.01 to 2.08). Other analyses by types of fibre intervention were not statistically significant. The overall dropout rate was over 16% in these trials with no reasons given for these losses. Sensitivity analysis incorporating these missing data shows that none of the results can be considered as robust; when the large numbers of participants lost to follow-up were assumed to have had an event or not, the results changed sufficiently to alter the conclusions that we would draw. Therefore, the reliability of the findings may have been compromised by these missing data (attrition bias) and should be interpreted with caution.

AUTHORS' CONCLUSIONS

There is a lack of evidence from existing RCTs to suggest that increased dietary fibre intake will reduce the recurrence of adenomatous polyps in those with a history of adenomatous polyps within a two to eight year period. However, these results may be unreliable and should be interpreted cautiously, not only because of the high rate of loss to follow-up, but also because adenomatous polyp is a surrogate outcome for the unobserved true endpoint CRC. Longer-term trials with higher dietary fibre levels are needed to enable confident conclusion.

The effects of nutritional interventions on recurrence in survivors of colorectal adenomas and cancer: a systematic review of randomised controlled trials

BACKGROUND/OBJECTIVES

Nutrition and dietary supplementation may modulate outcomes in colorectal cancer (CRC) survivors. However, no recent systematic review has focused on randomised controlled trials (RCTs). The aim of this systematic review was to examine the effects of nutritional RCTs in survivors of colorectal adenomas and cancer.

SUBJECTS/METHODS

Medline, Embase, Scopus, Web of Science and the Cochrane Library were searched to identify research between April 2006 and January 2014. The primary outcomes were colorectal adenoma and cancer recurrence. Each included study was assessed for risk of bias. A meta-analysis using a random-effects model was performed, in which two or more RCTs investigated the same dietary intervention.

RESULTS

Eight completed RCTs, all in colorectal adenoma survivors, were identified, with four investigating the effect of folic acid. A meta-analysis of the four folic acid RCTs showed no statistically significant effect of folic acid on colorectal adenoma recurrence (relative risks=0.93; 95% confidence interval: 0.69, 1.25). The impact of the remaining completed RCTs, investigating antioxidant supplementation, green tea extract, prebiotic fibre and phytooestrogens/insoluble fibre, could not be reliably estimated because of the limited number and heterogeneity of the interventions. In addition, three heterogeneous ongoing RCTs were identified, investigating green tea (n=1) and eicosapentaenoic acid (n=1) in colorectal adenoma survivors and dietary modifications (n=1) in CRC survivors in remission.

CONCLUSIONS

Overall, this systematic review highlights the need for further research, especially in CRC survivors, as we identified no completed and only one ongoing RCT in this population.

Effect of nutritional diet improvement on the digestive system of intensive care unit patients

AIM: To investigate the effect of improvement of nutritional diet on the digestive system of intensive care unit (ICU) patients.

METHODS: One hundred and twenty-six ICU patients treated from January and December 2014 at our hospital were randomly divided into an observation group and a control group, with 63 cases in each group. All cases received early enteral nutrition through a nasogastric tube. Nutrition was used in the control group, while an improved nutritional diet, which mixed Sanku compound nutrition and protein nutrition at 2:1, was used in the observation group. The incidences of gastrointestinal complications such as diarrhea, constipation, and gastric retention, score of gastrointestinal function and patient's

satisfaction were compared between the two groups.

RESULTS: The incidences of diarrhea, constipation, and gastric retention after nasal feeding in the observation group were significantly lower than those in the control group (P < 0.05). The scores of gastrointestinal function on 3 and 7 d after nasal feeding in the observation group were significantly lower than those in the control group (P < 0.05). The patients' satisfaction and total satisfaction rate in the observation group were significantly better than those in the control group (P < 0.05).

CONCLUSION: Nutritional diet improvement in ICU patients could significantly reduce the risk of gastrointestinal dysfunction, promote the recovery of digestive system function, and improve the patients' satisfaction.

Association between factors associated with colorectal cancer and rectal aberrant crypt foci in humans

Aberrant crypt foci (ACF) are regarded as potential biomarkers for colorectal cancer (CRC), and have been used as such in recent early-phase chemoprevention trials. However, the associations between the presence of ACF and other factors associated with the development of CRC, such as lifestyle factors, medication use and comorbid medical conditions, remain unknown. Thus, the present retrospective, large, cross-sectional study was conducted to evaluate the potential usefulness of ACF as a surrogate biomarker of CRC. Total colonoscopy was performed and the number of rectal ACF was counted in a total of 902 subjects. A retrospective review of the medical records of the study subjects was performed, and the factors associated with the increased prevalence of ACF was investigated using univariate and multivariate logistic regression analyses. The analysis results identified older age [odds ratio (OR), 9.24; 95% confidence interval (CI), 4.80-17.8; P<0.01], smoking habit (OR, 1.78; 95% CI, 1.20-2.63; P<0.01) and use of insulin (OR, 9.97; 95% CI, 1.28-77.5; P=0.03) as significant independent risk factors associated with the increased prevalence of ACF, regardless of the presence/absence of colon tumors. In addition, it was revealed that the prevalence and number of ACF, and the Ki-67 labeling indices of the colonic epithelial cells were significantly higher in diabetic patients receiving insulin therapy than in those not receiving insulin therapy (P<0.01, P=0.03 and P=0.01, respectively). In conclusion, the potential usefulness of ACF as a surrogate biomarker of CRC was confirmed, although useful data could not be obtained on candidate chemopreventive agents. These results indicated that insulin can enhance colonic epithelial proliferative activity and induce the formation of ACF, thereby possibly triggering CRC development.

Effects of glutamine and valsartan on the brain natriuretic peptide and N-terminal pro-B-type natriuretic peptide of patients with chronic heart failure

OBJECTIVE

To analyze the effects of glutamine and valsartan on the brain natriuretic peptide (BNP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) of patients with chronic heart failure (CHF).

METHODS

A total of 140 CHF patients were divided into a treatment group and a control group by random drawing, and were subjected to standard anti-heart failure treatment and administered with valsartan. Besides, the treatment group was also intravenously transfused glutamine. The treatment lasted eight weeks.

RESULTS

The overall efficacy of treatment group and control group were 98.6% and 90.0% respectively, with a statistically significant difference (P<0.05). The two groups had significantly increased left ventricular ejection fractions as well as significantly decreased left ventricular end-diastolic volumes and left ventricular end-diastolic dimensions after treatments (P<0.05) compared with those before. There were also inter-group differences between these values (P<0.05). After treatment, the levels of BNP, NT-proBNP and CD8(+) in both groups significantly decreased (P<0.05), whereas those of CD4(+) significantly increased (P<0.05). The two groups also had significantly different values (P<0.05).

CONCLUSION

Glutamine in combination with valsartan enhanced the therapeutic effects by improving cardiac function, which may be associated with decreased expressions of BNP and NT-proBNP and beneficial effects of glutamine on immune function.

Statins are potential anticancerous agents (review)

Statins are inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), which is a rate-limiting enzyme in the mevalonate pathway. The pleiotropic effects of statins may be mediated by the inhibition of downstream products such as small GTP-binding proteins, Rho, Ras and Rac whose localization and function are dependent on isoprenylation. Preclinical studies of statins in different cancer cell lines and animal models showed antiproliferative, pro‑apoptotic and anti-invasive effects. Notably, statins showed targeted action in cancerous cell lines compared to normal cells. Previous studies have also shown the synergistic effects of statins with chemotherapeutic agents and radiotherapy. This effect of statins was also observed in chemotherapeutic-resistant tumors. Statins were reported to sensitize the cells to radiation by arresting them in the late G1 phase of the cell cycle. Similarly, population-based studies also demonstrated a chemopreventive and survival benefit of statins in various types of cancers. However, this benefit has yet to be proven in clinical trials. The inter-individual variation in response to statins may be contributed to many genetic and non-genetic factors, including single-nucleotide polymorphisms in HMGCR gene and the overexpression of heterogeneous nuclear ribonucleoprotein A1, which was reported to reduce HMGCR enzyme activity. However, more studies with large phase III randomized controlled trials in cancer patients should be conducted to establish the effect of stains in cancer prevention and treatment.

Statins in oncological research: from experimental studies to clinical practice

Statins, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors are commonly used drugs in the treatment of dyslipidemias, primarily raised cholesterol. Recently, many epidemiological and preclinical studies pointed to anti-tumor properties of statins, including anti-proliferative activities, apoptosis, decreased angiogenesis and metastasis. These processes play an important role in carcinogenesis and, therefore, the role of statins in cancer disease is being seriously discussed among oncologists. Anti-neoplastic properties of statins combined with an acceptable toxicity profile in the majority of individuals support their further development as anti-tumor drugs. The mechanism of action, current preclinical studies and clinical efficacy of statins are reviewed in this paper. Moreover, promising results have been reported regarding the statins' efficacy in some cancer types, especially in esophageal and colorectal cancers, and hepatocellular carcinoma. Statins' hepatotoxicity has traditionally represented an obstacle to the prescription of this class of drugs and this issue is also discussed in this review.

Statin treatment reduces the risk of hepatocellular carcinoma but not colon cancer-results from a nationwide case-control study in Sweden

BACKGROUND

Several studies have indicated that statins may have anticarcinogenic effects. The aim of the present study was to investigate if statin treatment was associated with a reduced risk of hepatocellular carcinoma (HCC) or colon cancer.

METHODS

A nationwide case-control study was carried out in which all cases of HCC and colon cancer in the Swedish population above 40 years of age between 1 July 2006 and 31 December 2010 were identified in the Swedish Cancer Register. For every case, five controls were selected and matched on age and sex. Data on statin use was extracted from the Swedish Prescribed Drug Register. We estimated risks using conditional logistic regression and adjusted for educational level, concomitant medications and comorbidity.

RESULTS

Identified were 3994 cases of HCC and matched with 19.970 controls, and 21.143 cases of colon cancer were identified and matched with 105.715 controls. In the adjusted analysis, the odds ratio (OR) for HCC among statin users was 0.88 (95% confidence interval (CI) 0.81-0.96), and the OR for colon cancer was 1.04 (95%CI 1.00-1.08) compared with non-users.

CONCLUSION

Statin use was associated with a modest decreased risk of HCC but did not influence the risk of colon cancer. Future randomized placebo-controlled trials in HCC high-risk patients are warranted to further investigate the possible prophylactic effect of statins in HCC.

Deconstructing breast cancer cell biology and the mechanisms of multidrug resistance

Cancer complexity constantly challenges the way that clinicians manage breast cancer therapy. Tumor heterogeneity and intratumoral stroma characteristics allow cells with different phenotypes and deregulated apoptotic, proliferative and migration abilities to co-exist contributing to a disappointing therapeutic response. While new approaches are being associated with conventional chemotherapy, such as hormonal therapy or target monoclonal antibodies, recurrence and metastasization are still observed. Membrane transporters are the cell's first line of contact with anticancer drugs having a major role in multidrug resistance events. This structural-based activity enables the cell to be drug-resistant by decreasing drug intracellular concentration through an efflux-transport mechanism, mainly associated with overexpression of ATP-binding cassette (ABC) proteins. This review focuses on some of the important structural and biological properties of the malignant cell and tumor microenvironment, addressing the role of the membrane ABC transporters in therapeutic outcomes, and highlighting related molecular pathways that may represent meaningful target therapies.

Cancer, inflammation, and therapy: effects on cytochrome p450-mediated drug metabolism and implications for novel immunotherapeutic agents

Immune system activation through innate and adaptive systemic mechanisms is critical for protection from pathogens and other antigens. However, uncontrolled systemic inflammation may occur as a consequence of acute and chronic conditions and has multiple clinically relevant effects. Inflammation and cancer are fundamentally linked during development, invasion, and metastasis, yet, paradoxically, many cancers evade immune system detection. Components of cancer inflammation include chemokines, prostaglandins, and cytokines, and these have been shown to downregulate cytochrome P450 (CYP) enzyme activity. Recently, promising novel anticancer agents that upregulate immune responses have entered into clinical practice and have shown high response rates. These agents, either alone or in combinations, may cause systemic immune-related adverse events, with potential clinical implications for use of concurrent agents metabolized by CYP and other pathways. In this article, the authors focus on what is known about inflammation, cancer, and CYP-mediated drug metabolism; discuss clinical and pharmacologic data regarding novel immunomodulators; and consider their potential interactions with concurrent agents.

Clinical effects of glutamine and dietary fiber enhanced enteral nutrition in critically ill trauma patients

AIM: To explore the clinical effects of glutamine and dietary fiber enhanced enteral nutrition (EN) in critically ill trauma patients.

METHODS: Eighty-six patients with critically ill trauma were randomly divided into either an experiment group or a control group. Patients in both groups were treated by conventional EN. On the basis of conventional EN, the experiment group was additionally given glutamine (Gln) and soluble dietary fiber. The levels of heamoglobin (HGB), total serum protein (TP), albumin (ALB), CD4⁺, CD8⁺, CD4⁺/CD8⁺, IgA, IgG, IgM, fasting blood glucose (FBG), C-reactive protein (CRP) and the gastrointestinal adverse effects were compared between the two groups and between before and after treatment.

RESULTS: In both groups, the levels of HGB, TP, ALB, CD4⁺, CD4⁺/CD8⁺, IgA, IgG, and IgM were significantly higher (130.77 g/L ± 10.21 g/L vs 94.55 g/L ± 7.24 g/L, 67.87 g/L ± 2.21 g/L vs 50.95 g/L ± 10.23 g/L, 36.87 g/L ± 2.41 g/L vs 21.55 g/L ± 4.24 g/L, 50.02% ± 8.62% vs 42.19%± 9.52%, 2.37 ± 0.06 vs 1.61 ± 0.08, 3.32 g/L ± 0.67 g/L vs 2.20 g/L ± 0.69 g/L, 15.11 g/L ± 3.85 g/L vs 10.40 g/L ± 2.59 g/L, 1.79 g/L ± 0.45 g/L vs 1.39 g/L ± 0.49 g/L, 110.39 g/L ± 9.88 g/L vs 97.72 g/L ± 8.36 g/L, 59.39 g/L ± 3.00 g/L vs 40.77 g/L ± 3.06 g/L, 30.79 g/L ± 2.33 g/L vs 20.59 g/L ± 5.54 g/L, 46.22% ± 6.58% vs 41.44% ± 7.87%, 2.53 ± 0.06 vs 1.67 ± 0.07, 2.45 g/L ± 0.51 g/L vs 2.19 g/L ± 0.65 g/L, 12.24 g/L ± 3.82 g/L vs 10.48 g/L ± 3.03 g/L, 1.69 g/L ± 0.53 g/L vs 1.24 g/L ± 0.44 g/L; P < 0.05 or P < 0.01), and the levels of CD8⁺, FBG, and CRP were significantly lower (19.94% ± 2.66% vs 25.20% ± 5.27%, 8.11 mmol/L ± 2.06 mmol/L vs 14.57 mmol/L ± 2.12 mmol/L, 1.49 mg/L ± 0.39 mg/L vs 6.53 mg/L L ± 1.33 mg/L, 19.13% ± 2.15% vs 25.17% ± 3.32%, 10.79 mmol/L ± 1.33 mmol/L vs 14.64 mmol/L ± 2.31 mmol/L, 5.19 mg/L ± 2.11 mg/L vs 6.51 mg/L ± 1.44 mg/L; P < 0.05 or P < 0.01) after EN than before EN. After EN, the levels of HGB, TP, ALB, CD4⁺, IgA, and IgG in the experiment group were significantly higher than those in the control group (130.77 g/L ± 10.21 g/L vs 110.39 g/L ± 9.88 g/L, 67.87 g/L ± 2.21 g/L vs 59.39 g/L ± 3.00 g/L, 36.87 g/L ± 2.41 g/L vs 30.79 g/L ± 2.33 g/L, 50.02% ± 8.62% vs 46.22% ± 6.58%, 3.32 g/L ± 0.67 g/L vs 2.45 g/L ± 0.51 g/L, 15.11 g/L ± 3.85 g/L vs 12.24 g/L ± 3.82 g/L; P < 0.05 or P < 0.01), while the levels of FBG, CRP and the rate of constipation were significantly lower in the experiment group than in the control group (8.11 mmol/L ± 2.06 mmol/L vs 10.79 mmol/L ± 1.33 mmol/L, 1.49 mg/L ± 0.39 mg/L vs 5.19 mg/L ± 2.11 mg/L, 13.95% vs 30.23%; P < 0.05 or P < 0.01).

CONCLUSION: Glutamine and dietary fiber enhanced enteral nutrition can improve the nutritional status and immune function, promote the gastrointestinal vermicular motion, and thereby improve the gastrointestinal function.

Association between statin use and colorectal cancer risk: a meta-analysis of 42 studies

PURPOSE

There is a long-standing debate about whether statins have chemopreventive properties against colorectal cancer (CRC), but the results remain inconclusive. We therefore present a meta-analysis to investigate the association between statin use and risk of CRC.

METHODS

A comprehensive literature search was undertaken through July 2013 looking for eligible studies. Pooled relative risk (RR) estimates and 95 % confidence intervals (CIs) were used to calculate estimated effect.

RESULTS

Forty-two studies [18 case-control studies, 13 cohort studies, and 11 randomized controlled trials (RCTs)] were included in this analysis. Overall, statin use was associated with a modest reduction in the risk of CRC (RR = 0.90, 95 % CI 0.86-0.95). When the analyses were stratified into subgroups, a significant decreased association of CRC risk was observed in observational studies (RR = 0.89, 95 % CI 0.84-0.95), rectal cancer (RR = 0.81, 95 % CI 0.66-0.99), and lipophilic statin (RR = 0.88, 95 % CI 0.85-0.93), but not in RCTs (RR = 0.96, 95 % CI 0.85-1.08), colon cancer, and hydrophilic statin. However, long-term statin use (≥5 years) did not significantly affect the risk of CRC (RR = 0.96, 95 % CI 0.90-1.03). Cumulative meta-analysis showed that statin use significantly reduces the risk of CRC, which has been available between 2007 and 2013.

CONCLUSIONS

Our results suggest that statin use is associated with a modest reduced risk of CRC; apparent associations were found for lipophilic statin use. However, long-term statin use did not appear to significantly affect the risk of CRC.

Nutraceuticals for older people: facts, fictions and gaps in knowledge

In the last decades nutraceuticals have entered the health market as an easy and attractive means of preventing diseases. These products are of interest for an increasingly health-concerned society and may be especially relevant for preventing or delaying a number of age-related diseases, i.e. arthritis, cancer, metabolic and cardiovascular diseases, osteoporosis, cataracts, brain disorders, etc. Nutraceuticals are marketed in a variety of forms, composition and potential applications which have made their definition ambiguous and their use uncontrolled and poorly funded. Although epidemiological, animal and in vitro studies have given evidence of the potential benefits of some of these nutraceuticals or of their components, definitive proof of their effects in appropriate human clinical trials is still lacking in most cases, more critically among people above 65 years of age. We cover the well-established nutraceuticals (polyvitamins, omega-3 fatty acids, etc.) and will focus on many other 'novel' commercial nutraceuticals where the scientific evidence is more limited (food extracts, polyphenols, carotenoids, etc.). Solid scientific evidence has been reported only for a few nutraceuticals, which have some health claims approved by the European Food Safety Authority (EFSA). Further well-designed trials are needed to improve the current knowledge on the health benefits of nutraceuticals in the elderly. Overall, there are some facts, a lot of fiction and many gaps in the knowledge of nutraceutical benefits.

Fiber and prebiotics: mechanisms and health benefits

The health benefits of dietary fiber have long been appreciated. Higher intakes of dietary fiber are linked to less cardiovascular disease and fiber plays a role in gut health, with many effective laxatives actually isolated fiber sources. Higher intakes of fiber are linked to lower body weights. Only polysaccharides were included in dietary fiber originally, but more recent definitions have included oligosaccharides as dietary fiber, not based on their chemical measurement as dietary fiber by the accepted total dietary fiber (TDF) method, but on their physiological effects. Inulin, fructo-oligosaccharides, and other oligosaccharides are included as fiber in food labels in the US. Additionally, oligosaccharides are the best known "prebiotics", "a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microflora that confers benefits upon host well-bring and health." To date, all known and suspected prebiotics are carbohydrate compounds, primarily oligosaccharides, known to resist digestion in the human small intestine and reach the colon where they are fermented by the gut microflora. Studies have provided evidence that inulin and oligofructose (OF), lactulose, and resistant starch (RS) meet all aspects of the definition, including the stimulation of Bifidobacterium, a beneficial bacterial genus. Other isolated carbohydrates and carbohydrate-containing foods, including galactooligosaccharides (GOS), transgalactooligosaccharides (TOS), polydextrose, wheat dextrin, acacia gum, psyllium, banana, whole grain wheat, and whole grain corn also have prebiotic effects.

Statins and colorectal cancer

The 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, more commonly referred to as statins, comprise a family of lipid-lowering drugs that are prescribed on a global scale on account of their proven safety and efficacy in reducing mortality from cardiovascular disease. Beyond their potent pharmacologic inhibition of cholesterol biosynthesis, statins appear to have pleiotropic effects, including modulation of cell growth, apoptosis, and inflammation. Through modulation of these pathways, statins have the potential to influence a wide range of disease processes, including cancer. Much attention has focused on the association between statins and colorectal cancer, raising the prospect that these well-tolerated compounds could form the basis of future chemopreventive strategies. Herein, we review the epidemiologic, clinical, and preclinical data relevant to statins and colorectal neoplasia, and discuss the current status and future potential of statins as chemopreventive agents.

Effect of prebiotics on biomarkers of colorectal cancer in humans: a systematic review

Prebiotics may prevent colorectal cancer (CRC) development in humans by modifying the composition or activity of the colorectal microflora. Epidemiologic and animal studies have shown a reduction in CRC or CRC biomarkers after the administration of prebiotics. Studies using indirect chemical biomarkers of CRC in humans, however, gave mixed results. Recently, human studies measuring direct physical indices of CRC risk after prebiotic consumption have been published. The purpose of this review is to summarize those studies to provide recommendations for the use of prebiotics in CRC risk reduction. A PubMed search was conducted, revealing nine studies. One tested lactulose, two evaluated a blend of oligofructose and inulin, and six measured resistant starch. Lactulose reduced adenoma recurrence, while resistant starch had no effect on adenoma or CRC development. Crypt mitotic location, gene expression, and DNA methylation were somewhat improved after resistant starch consumption. No changes in cell proliferation and apoptosis, crypt morphology, or aberrant crypt foci were found. More human studies measuring physical changes to the gut are needed.

Sulindac sulfide--induced stimulation of eryptosis

BACKGROUND

Sulindac sulfide, a non-steroidal anti-inflammatory drug (NSAID), stimulates apoptosis of tumor cells and is thus effective against malignancy. In analogy to apoptosis of nucleated cells, erythrocytes may undergo eryptosis, an apoptosis-like suicidal erythrocyte death, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine-exposure at the cell surface. Stimulators of eryptosis include increase of cytosolic Ca(2+)-activity ([Ca(2+)](i)) and ceramide formation. The present study explored, whether sulindac sulfide stimulates eryptosis.

METHODS

[Ca(2+)](i) was estimated from Fluo-3 fluorescence, cell volume from forward scatter, phosphatidylserine-exposure from binding of fluorescent annexin-V, hemolysis from hemoglobin release, and ceramide abundance utilizing fluorescent antibodies.

RESULTS

A 48 h exposure to sulindac sulfide (≤ 20 µM) was followed by significant increase of [Ca(2+)](i), enhanced ceramide abundance, decreased forward scatter and increased percentage of annexin-V-binding erythrocytes. Sulindac sulfide triggered slight but significant hemolysis. Removal of extracellular Ca(2+) significantly blunted, but did not abrogate the effect of sulindac sulfide (20 µM) on annexin-V-binding.

CONCLUSION

Sulindac sulfide stimulates the suicidal death of erythrocytes or eryptosis, an effect paralleled by Ca(2+)-entry, ceramide formation, cell shrinkage and phosphatidylserine-exposure.

Number of aberrant crypt foci in the rectum is a useful surrogate marker of colorectal adenoma recurrence

AIM

Endoscopic screening and removal of colorectal adenomas can reduce the incidence of colorectal cancer. However, given the possibility of adenoma recurrence, surveillance colonoscopy is currently recommended after the initial screening and removal of colorectal adenomas. Aberrant crypt foci (ACF) have been shown to serve as a reliable surrogate marker of colorectal carcinogenesis. In this study, the relationship between the number of ACF at the initial endoscopic polypectomy and the likelihood of colorectal adenoma recurrence after polypectomy were investigated.

METHODS

High-magnification chromoscopic colonoscopy was performed in 82 subjects who underwent endoscopic polypectomy to identify ACF in the lower rectum. Surveillance colonoscopy was then performed 3 years after the baseline polypectomy at Yokohama City University Hospital.

RESULTS

The number of ACF was greater in patients who showed adenoma recurrence (7.88 ± 6.35) than in those who did not (2.19 ± 2.95) (P < 0.001). Receiver-operating curve analysis showed that the number of ACF was a highly specific predictor of the risk of adenoma recurrence.

CONCLUSIONS

This is the first study conducted to investigate the relationship between the number of ACF after endoscopic polypectomy and the likelihood of recurrence of colorectal adenomas. These results suggest that the number of ACF is a useful predictor of the likelihood of colorectal adenoma recurrence.

Prebiotics and the health benefits of fiber: current regulatory status, future research, and goals

First defined in the mid-1990s, prebiotics, which alter the composition and activity of gastrointestinal (GI) microbiota to improve health and well-being, have generated scientific and consumer interest and regulatory debate. The Life Sciences Research Organization, Inc. (LSRO) held a workshop, Prebiotics and the Health Benefits of Fiber: Future Research and Goals, in February 2011 to assess the current state of the science and the international regulatory environment for prebiotics, identify research gaps, and create a strategy for future research. A developing body of evidence supports a role for prebiotics in reducing the risk and severity of GI infection and inflammation, including diarrhea, inflammatory bowel disease, and ulcerative colitis as well as bowel function disorders, including irritable bowel syndrome. Prebiotics also increase the bioavailability and uptake of minerals and data suggest that they reduce the risk of obesity by promoting satiety and weight loss. Additional research is needed to define the relationship between the consumption of different prebiotics and improvement of human health. New information derived from the characterization of the composition and function of different prebiotics as well as the interactions among and between gut microbiota and the human host would improve our understanding of the effects of prebiotics on health and disease and could assist in surmounting regulatory issues related to prebiotic use.

Chemoprevention of mouse lung and colon tumors by suberoylanilide hydroxamic acid and atorvastatin

Atorvastatin and suberoylanilide hydroxamic acid (SAHA) were evaluated for chemoprevention of mouse lung tumors. In Experiment 1, lung tumors were induced by vinyl carbamate in strain A/J mice followed by 500 mg/kg SAHA, 60 or 180 mg/kg atorvastatin, and combinations containing SAHA and atorvastatin administered in their diet. SAHA and both combinations, but not atorvastatin, decreased the multiplicity of lung tumors, including large adenomas and adenocarcinomas with the combinations demonstrating the greatest efficacy. In Experiment 2, lung tumors were induced by 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanol in strain A/J mice followed by 180 mg/kg atorvastatin, 500 mg/kg SAHA, or both drugs administered in the diet. SAHA and the combination of both drugs, but not atorvastatin alone, decreased the multiplicity of lung tumors and large tumors, with the combination demonstrating greater efficacy. In Experiment 3, lung tumors were induced by 1,2-dimethylhydrazine in Swiss-Webster mice followed by 160 mg/kg atorvastatin, 400 mg/kg SAHA, or a combination of both drugs administered in the diet. SAHA and the combination, but not atorvastatin, decreased the multiplicity of lung tumors with the combination demonstrating greater efficacy. The multiplicity of colon tumors was decreased by SAHA, atorvastatin, and the combination, without any significant difference in their efficacy. mRNA expression analysis of lung tumor bearing mice suggested that the enhanced chemopreventive activity of the combination is related to atorvastatin modulation of DNA repair, SAHA modulation of angiogenesis, and both drugs modulating invasion and metastasis pathways. Atorvastatin demonstrated chemoprevention activity as indicated by the enhancement of the efficacy of SAHA to prevent mouse lung tumors.

Pharmacology and cellular/molecular mechanisms of action of aspirin and non-aspirin NSAIDs in colorectal cancer

Colorectal cancer (CRC) and colorectal adenomas have in common a dysfunctional adenomatous polyposis coli suppressor gene (APC). This allows for activation of the oncogenic Wnt/β-catenin pathway, resulting in cytosolic accumulation of β-catenin, its translocation to the nucleus and action as a cofactor for stimulation of gene transcription. Pharmacological approaches of CRC-chemoprevention are focused to prevention of this β-catenin-mediated oncogenic signalling. Among upregulated genes in tumour tissue is COX-2 which synthesises large amounts of PGE(2). PGE(2) inhibits apoptosis, acts proinflammatory and immunosuppressive and stimulates tumour angiogenesis and proliferation. In addition, COX-2 causes oxidation (activation) of cocarcinogens. Aspirin and non-aspirin NSAIDs inhibit COX-2, subsequent PGE(2) formation and action by transcriptional and non-transcriptional mechanisms. These also include inhibition of generation of sphingosine-1-phosphate, an amplifier of these reactions and stimulation of NSAID-induced gene (NAG-1) which acts as an inhibitor. Aspirin additionally acetylates COX-2, resulting in generation of 'aspirin-triggered' lipoxins (ATL), a new class of anti-inflammatory/antitumour compounds. COX-1 inhibition might also contribute to antitumour effects of aspirin, for example at low-dose aspirin. Experimental evidence suggests additional COX independent actions of aspirin and non-aspirin NSAIDs on oncogenic signalling. This includes modifications of transcription factors (NFκB), induction of apoptosis and DNA stabilization. In comparison to non-aspirin NSAIDs (sulindac, indomethacin) and coxibs (celecoxib), aspirin has the advantage of concomitant antiplatelet effects while NSAIDs rather have a thrombogenic potential. Though these actions of aspirin have to be balanced against an increased bleeding tendency, aspirin is currently the most attractive candidate for clinical CRC chemoprevention. Open questions, such as dose, (minimum) duration of treatment and the individual risk/benefit ratio are subjects of prospective randomized trials which are underway.

Coxibs and other nonsteroidal anti-inflammatory drugs in animal models of cancer chemoprevention

Coxibs, including celecoxib, and other nonsteroidal anti-inflammatory drugs (NSAID), including aspirin, are among the most promising cancer chemopreventive agents in development today. This article examines the data on the efficacy of these agents in animal model studies of cancer prevention carried out by the authors. The studies evaluated here are restricted to our rodent models of colon/intestinal, bladder, and nonmelanoma skin cancer, in which celecoxib and other NSAIDs were administered as either cancer preventive or therapeutic agents. These studies may shed light on several questions. Is celecoxib unique compared with other NSAIDs, and if so, what implications would this have for human use? Are standard NSAIDs (which inhibit both COX-1 and COX-2) as effective as celecoxib in animal studies? Is the efficacy of celecoxib in particular or NSAIDs in general due to their off-target effects or to their effects on COX-1 and COX-2? What is the likely efficacy of low-dose aspirin? Some questions raised by human trials and epidemiology are discussed and related to our observations in animal model studies. We also discuss the problem of cardiovascular (CV) events associated with coxibs and certain other NSAIDs and whether results in animal models are predictive of efficacy in humans. On the basis of epidemiologic studies and its CV profile, aspirin seems to be the most promising NSAID for preventing human colorectal, bladder, and skin cancer, although the animal data for aspirin are less clear. A comprehensive understanding of the results of coxibs and other NSAIDs in animal studies may help inform and shape human trials of these commonly employed, relatively inexpensive, and highly effective compounds.