Mesalazine causes a mitotic arrest and induces caspase-dependent apoptosis in colon carcinoma cells

Phase IV Metabolism: Gut Microbial Metabolism of Common Gastrointestinal Drugs

Intestinal microbiota possess a plethora of biotransformation capabilities, which can modify medications, including their Phase I or II metabolites in a process termed "Phase IV" metabolism. Phase IV metabolism is emerging as a significant contributor to interindividual variability in drug responses. Here we present examples of gastrointestinal-relevant medications that are known to be subject to bacterial Phase IV metabolism and propose avenues to improve precision medicine by modulating these bacterial functions.

Colorectal cancer: Recent advances in management and treatment

Colorectal cancer (CRC) is the third most common cancer worldwide, and the second most common cause of cancer-related death. In 2020, the estimated number of deaths due to CRC was approximately 930000, accounting for 10% of all cancer deaths worldwide. Accordingly, there is a vast amount of ongoing research aiming to find new and improved treatment modalities for CRC that can potentially increase survival and decrease overall morbidity and mortality. Current management strategies for CRC include surgical procedures for resectable cases, and radiotherapy, chemotherapy, and immunotherapy, in addition to their combination, for non-resectable tumors. Despite these options, CRC remains incurable in 50% of cases. Nonetheless, significant improvements in research techniques have allowed for treatment approaches for CRC to be frequently updated, leading to the availability of new drugs and therapeutic strategies. This review summarizes the most recent therapeutic approaches for CRC, with special emphasis on new strategies that are currently being studied and have great potential to improve the prognosis and lifespan of patients with CRC.

Molecular Mechanisms of the Antitumor Effects of Mesalazine and Its Preventive Potential in Colorectal Cancer

Chemoprevention is one of the ways to fight colorectal cancer, which is a huge challenge in oncology. Numerous pieces of evidence indicate that chronic inflammation in the course of Crohn's disease or ulcerative colitis (UC) is a significant cancer risk factor. Epidemiologic studies suggest that long-term use of non-steroidal anti-inflammatory drugs (NSAIDs), including mesalazine, has beneficial effects on colitis-associated colorectal cancer. Mesalazine is a first-line therapy for UC and is also widely used for maintaining remission in UC. Data showed that mesalazine has antiproliferative properties associated with cyclooxygenase (COX) inhibition but can also act through COX-independent pathways. This review summarizes knowledge about mesalazine's molecular mechanisms of action and chemopreventive effect by which it could interfere with colorectal cancer cell proliferation and survival.

Drug Repurposing Strategies for Non-Cancer to Cancer Therapeutics

Global efforts invested for the prevention and treatment of cancer need to be repositioned to develop safe, effective, and economic anticancer therapeutics by adopting rational approaches of drug discovery. Drug repurposing is one of the established approaches to reposition old, clinically approved off patent noncancer drugs with known targets into newer indications. The literature review suggests key role of drug repurposing in the development of drugs intended for cancer as well as noncancer therapeutics. A wide category of noncancer drugs namely, drugs acting on CNS, anthelmintics, cardiovascular drugs, antimalarial drugs, anti-inflammatory drugs have come out with interesting outcomes during preclinical and clinical phases. In the present article a comprehensive overview of the current scenario of drug repurposing for the treatment of cancer has been focused. The details of some successful studies along with examples have been included followed by associated challenges.

Sodium salicylate and 5-aminosalicylic acid synergistically inhibit the growth of human colon cancer cells and mouse intestinal polyp-derived cells

As colon cancer is one of the most common cancers in the world, practical prevention strategies for colon cancer are needed. Recently, treatment with aspirin and/or 5-aminosalicylic acid-related agents was reported to reduce the number of intestinal polyps in patients with familial adenomatous polyposis. To evaluate the mechanism of aspirin and 5-aminosalicylic acid for suppressing the colon polyp growth, single and combined effects of 5-aminosalicylic acid and sodium salicylate (metabolite of aspirin) were tested in the two human colon cancer cells with different cyclooxygenase-2 expression levels and intestinal polyp-derived cells from familial adenomatous polyposis model mouse. The combination induced cell-cycle arrest at the G1 phase along with inhibition of cell growth and colony-forming ability in these cells. The combination reduced cyclin D1 via proteasomal degradation and activated retinoblastoma protein. The combination inhibited the colony-forming ability of mouse colonic mucosa cells by about 50% and the colony-forming ability of mouse intestinal polyp-derived cells by about 90%. The expression level of cyclin D1 in colon mucosa cells was lower than that in intestinal polyp-derived cells. These results suggest that this combination may be more effective in inhibiting cell growth of intestinal polyps through cyclin D1 down-regulation.

Mesalazine initiates an anti-oncogenic β-catenin / MUCDHL negative feed-back loop in colon cancer cells by cell-specific mechanisms

Chronic inflammation associated with intestinal architecture and barrier disruption puts patients with inflammatory bowel disease (IBD) at increased risk of developing colorectal cancer (CRC). Widely used to reduce flares of intestinal inflammation, 5-aminosalicylic acid derivatives (5-ASAs) such as mesalazine appear to also exert more direct mucosal healing and chemopreventive activities against CRC. The mechanisms underlying these activities are poorly understood and may involve the up-regulation of the cadherin-related gene MUCDHL (CDHR5). This atypical cadherin is emerging as a new actor of intestinal homeostasis and opposes colon tumorigenesis. Here, we showed that mesalazine increase mRNA levels of MUCDHL and of other genes involved in the intestinal barrier function in most intestinal cell lines. In addition, using gain / loss of function experiments (agonists, plasmid or siRNAs transfections), luciferase reporter genes and chromatin immunoprecipitation, we thoroughly investigated the molecular mechanisms triggered by mesalazine that lead to the up-regulation of MUCDHL expression. We found that basal transcription of MUCDHL in different CRC cell lines is regulated positively by CDX2 and negatively by β-catenin through a negative feed-back loop. However, mesalazine-stimulation of MUCDHL transcription is controlled by cell-specific mechanisms, involving either enhanced activation of CDX2 and PPAR-γ or repression of the β-catenin inhibitory effect. This work highlights the importance of the cellular and molecular context in the activity of mesalazine and suggests that its efficacy against CRC depends on the genetic alterations of transformed cells.

Combining repurposed drugs to treat colorectal cancer

The drug development process, especially of antineoplastic agents, has become increasingly costly and ineffective. Drug repurposing and drug combination are alternatives to de novo drug development, being low cost, rapid, and easy to apply. These strategies allow higher efficacy, decreased toxicity, and overcoming of drug resistance. The combination of antineoplastic agents is already being applied in cancer therapy, but the combination of repurposed drugs is still under-explored in pre- and clinical development. In this review, we provide a set of pharmacological concepts focusing on drug repurposing for treating colorectal cancer (CRC) and that are relevant for the application of new drug combinations against this disease.

Systems-level biomarkers identification and drug repositioning in colorectal cancer

Colorectal cancer (CRC) is the most commonly diagnosed fatal cancer in both women and men worldwide. CRC ranked second in mortality and third in incidence in 2020. It is difficult to diagnose CRC at an early stage as there are no clinical symptoms. Despite advances in molecular biology, only a limited number of biomarkers have been translated into routine clinical practice to predict risk, prognosis and response to treatment. In the last decades, systems biology approaches at the omics level have gained importance. Over the years, several biomarkers for CRC have been discovered in terms of disease diagnosis and prognosis. On the other hand, a few drugs are being developed and used in clinics for the treatment of CRC. However, the development of new drugs is very costly and time-consuming as the research and development takes about 10 years and more than $1 billion. Therefore, drug repositioning (DR) could save time and money by establishing new indications for existing drugs. In this review, we aim to provide an overview of biomarkers for the diagnosis and prognosis of CRC from the systems biology perspective and insights into DR approaches for the prevention or treatment of CRC.

5-Aminosalicylic acid inhibits stem cell function in human adenoma-derived cells: implications for chemoprophylaxis in colorectal tumorigenesis

Background

Most colorectal cancers (CRC) arise sporadically from precursor lesions: colonic polyps. Polyp resection prevents progression to CRC. Risk of future polyps is proportional to the number and size of polyps detected at screening, allowing identification of high-risk individuals who may benefit from effective chemoprophylaxis. We aimed to investigate the potential of 5-aminosalicylic acid (5-ASA), a medication used in the treatment of ulcerative colitis, as a possible preventative agent for sporadic CRC.

Methods

Human colorectal adenoma (PC/AA/C1, S/AN/C1 and S/RG/C2), transformed adenoma PC/AA/C1/SB10 and carcinoma cell lines (LS174T and SW620) were treated with 5-ASA. The effect on growth in two- and three-dimensional (3D) culture, β-catenin transcriptional activity and on cancer stemness properties of the cells were investigated.

Results

5-ASA was shown, in vitro, to inhibit the growth of adenoma cells and suppress β-catenin transcriptional activity. Downregulation of β-catenin was found to repress expression of stem cell marker LGR5 (leucine-rich G protein-coupled receptor-5) and functionally suppress stemness in human adenoma and carcinoma cells using 3D models of tumorigenesis.

Conclusions

5-ASA can suppress the cancer stem phenotype in adenoma-derived cells. Affordable and well-tolerated, 5-ASA is an outstanding candidate as a chemoprophylactic medication to reduce the risk of colorectal polyps and CRC in those at high risk.

Drug repurposing in oncology: Compounds, pathways, phenotypes and computational approaches for colorectal cancer

The strategy of using existing drugs originally developed for one disease to treat other indications has found success across medical fields. Such drug repurposing promises faster access of drugs to patients while reducing costs in the long and difficult process of drug development. However, the number of existing drugs and diseases, together with the heterogeneity of patients and diseases, notably including cancers, can make repurposing time consuming and inefficient. The key question we address is how to efficiently repurpose an existing drug to treat a given indication. As drug efficacy remains the main bottleneck for overall success, we discuss the need for machine-learning computational methods in combination with specific phenotypic studies along with mechanistic studies, chemical genetics and omics assays to successfully predict disease-drug pairs. Such a pipeline could be particularly important to cancer patients who face heterogeneous, recurrent and metastatic disease and need fast and personalized treatments. Here we focus on drug repurposing for colorectal cancer and describe selected therapeutics already repositioned for its prevention and/or treatment as well as potential candidates. We consider this review as a selective compilation of approaches and methodologies, and argue how, taken together, they could bring drug repurposing to the next level.

Effect of Long-Term Mesalamine Therapy on Cancer-Associated Gene Expression in Colonic Mucosa of Patients with Ulcerative Colitis

BACKGROUND

The role of 5-aminosalicylic acid (5-ASA or mesalamine) in the prevention of colorectal cancer in ulcerative colitis (UC) patients was reported, but the effect on molecular targets in UC colon mucosa is unknown.

AIM

This observational study evaluates gene expression levels of 5-ASA targets using serial colon biopsy specimens from UC patients undergoing long-term 5-ASA therapy.

METHODS

Transcript levels were compared between colonoscopic biopsy specimens collected from 62 patients at initial and final follow-up colonoscopy at 2-6 years. All patients had mild-to-moderate UC and were undergoing long-term 5-ASA maintenance. Stepwise multiple linear regression analyses were performed to correlate changes in transcript levels with therapeutic response (Mayo clinical score endoscopy and DAI and/or Nancy histopathology score) and nonclinical variables.

RESULTS

The transcript levels of colorectal carcinogenesis-associated known 5-ASA target genes were significantly reduced after prolonged 5-ASA therapy (P < 0.005-0.03). Multiple linear regression models predicted significant association between transcript levels of Ki-67, NF-kB (p65), PPARγ, COX-2 and IL-8, CDC25A, and CXCL10 with duration of drug (5-ASA) exposure (P ≤ 0.05). Ki-67, NF-kB (p65), and CXCL10 transcripts were also correlated with reduced endoscopy sub-score (P ≤ 0.05). COX-2, IL-8, CDC25A, and TNF transcripts strongly correlated with DAI sub-scores (P ≤ 0.05). Only COX-2 and IL-8 transcript levels correlated (P ≤ 0.05) with Nancy histological score.

CONCLUSION

This study provides molecular evidence of changes in carcinogenesis-related targets/pathways in colon tissue during long-term 5-ASA maintenance therapy that may contribute to the observed chemopreventive effects of 5-ASA in UC patients.

Combination of metformin and 5-aminosalicylic acid cooperates to decrease proliferation and induce apoptosis in colorectal cancer cell lines

BACKGROUND

The link between inflammation and cancer has been confirmed by the use of anti-inflammatory therapies in cancer prevention and treatment. 5-aminosalicylic acid (5-ASA) was shown to decrease the growth and survival of colorectal cancer (CRC) cells. Studies also revealed that metformin induced apoptosis in several cancer cell lines.

METHODS

We investigated the combinatory effect of 5-ASA and metformin on HCT-116 and Caco-2 CRC cell lines. Apoptotic markers were determined using western blotting. Expression of pro-inflammatory cytokines was determined by RT-PCR. Inflammatory transcription factors and metastatic markers were measured by ELISA.

RESULTS

Metformin enhanced CRC cell death induced by 5-ASA through significant increase in oxidative stress and activation of apoptotic machinery. Moreover, metformin enhanced the anti-inflammatory effect of 5-ASA by decreasing the gene expression of IL-1β, IL-6, COX-2 and TNF-α and its receptors; TNF-R1 and TNF-R2. Significant inhibition of activation of NF-κB and STAT3 transcription factors, and their downstream targets was also observed. Metformin also enhanced the inhibitory effect of 5-ASA on MMP-2 and MMP-9 enzyme activity, indicating a decrease in metastasis.

CONCLUSION

The current data demonstrate that metformin potentiates the antitumor effect of 5-ASA on CRC cells suggesting their potential use as an adjuvant treatment in CRC.

Si Shen Wan Regulates Phospholipase Cγ-1 and PI3K/Akt Signal in Colonic Mucosa from Rats with Colitis

The present study explored the feasible pathway of Si Shen Wan (SSW) in inhibiting apoptosis of intestinal epithelial cells (IECs) by observing activation of phospholipase Cγ-1 (PLC-γ1) and PI3K/Akt signal in colonic mucosa from rats with colitis. Experimental colitis was induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) in the Sprague-Dawley rats. After SSW was administrated for 7 days after TNBS infusion, western blot showed an increment in levels of PI3K, p-Akt, and IL-23 and a decrement in levels of PLC-γ1 and HSP70 in colonic mucosal injury induced by TNBS. Meanwhile, assessments by ELISA revealed an increment in concentrations of IL-2, IL-6, and IL-17 and a reduction in level of TGF-β after TNBS challenge. Impressively, treatment with SSW for 7 days significantly attenuated the expressions of PI3K and p-Akt and the secretion of IL-2, IL-6, IL-17, and IL-23 and promoted the activation of PLC-γ1, HSP70, and TGF-β. Our previous studies had demonstrated that SSW restored colonic mucosal ulcers by inhibiting apoptosis of IECs. The present study demonstrated that the effect of SSW on inhibiting apoptosis of IECs was realized probably by activation of PLC-γ1 and suppression of PI3K/Akt signal pathway.

The effects of selected drugs and dietary compounds on proliferation and apoptosis in colorectal carcinoma

Like many malignancies, the development of colorectal carcinoma (CRC) can be considered as an imbalance between the compromised process of programmed cell death (apoptosis) and excessive, uncontrolled proliferation. Several mutations and epigenetic alterations are acquired during colorectal carcinogenesis. These are responsible for the cell cycle regulation, cellular sensitivity to pro- and antiapoptotic factors, cell proliferation, angiogenesis, invasiveness, as well as metastatic potential. The molecular alterations, along with their morphological expressions, have been recognised in detail, and most of the CRC cases can be attributed to either adenoma-carcinoma or serrated neoplasia pathways: in the first, the antiapoptotic features prevail; while in the second, the proliferative activity is of the utmost importance. The aim of the work is to discuss the influence of selected drugs and dietary compounds on the proliferation and apoptosis in CRC.

DUOX2 and DUOXA2 form the predominant enzyme system capable of producing the reactive oxygen species H2O2 in active ulcerative colitis and are modulated by 5-aminosalicylic acid

BACKGROUND

NADPH oxidase-derived reactive oxygen species, such as H2O2, are part of the intestinal innate immune system but may drive carcinogenesis through DNA damage. We sought to identify the predominant enzyme system capable of producing H2O2 in active ulcerative colitis and assess whether it is affected by 5-aminosalicylic acid (5-ASA).

METHODS

We studied human mucosal biopsies by expression arrays, quantitative real-time polymerase chain reaction for NADPH oxidase family members, in situ hybridization (DUOX2 and DUOXA2) and immunofluorescence for DUOX, 8-OHdG (DNA damage), and γH2AX (DNA damage response) and sought effects of 5-ASA on ex vivo cultured biopsies and cultured rectal cancer cells.

RESULTS

DUOX2 with maturation partner DUOXA2 forms the predominant system for H2O2 production in human colon and is upregulated in active colitis. DUOX2 in situ is exclusively epithelial, varies between and within individual crypts, and increases near inflammation. 8-OHdG and γH2AX were observed in damaged crypt epithelium. 5-ASA upregulated DUOX2 and DUOXA2 levels in the setting of active versus quiescent disease and altered DUOX2 expression in cultured biopsies. Ingenuity pathway analysis confirmed that inflammation status and 5-ASA increase expression of DUOX2 and DUOXA2. An epithelial cell model confirmed that cultured cancer cells expressed DUOX protein and produced H2O2 in response to hypoxia and 5-ASA exposure.

CONCLUSIONS

Both DUOX2 and DUOXA2 expression are involved specifically in inflammation and are regulated on a crypt-by-crypt basis in ulcerative colitis tissues. Synergy between inflammation, hypoxia, and 5-ASA to increase H2O2 production could explain how 5-ASA supports innate defense, although potentially increasing the burden of DNA damage.

The 5-aminosalicylic acid antineoplastic effect in the intestine is mediated by PPARγ

Epidemiological evidences suggested that 5-aminosalicylic acid (5-ASA) therapy may prevent the development of colorectal cancer in inflammatory bowel disease patients. Our aim is to investigate whether peroxisome proliferator-activated receptor-γ (PPARγ) mediates the antineoplastic effects of 5-ASA. HT-29 and Caco-2 cells were treated by 5-ASA, rosiglitazone (PPARγ ligand) or etoposide (anticarcinogenic drug). Epithelial cell growth, proliferation and apoptosis were assessed by cell count, Ki-67 staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, respectively. The antineoplastic effect of 5-ASA was evaluated in a xenograft tumor model in SCID mice and in azoxymethane (AOM)-induced colon carcinogenesis in A/JOlaHsd mice. The role of PPARγ was examined by administration of PPARγ antagonist, GW9662 and in PPAR knockdown cells. Compared with untreated cells, treatment of HT-29 cells by 5-ASA inhibited significantly cell growth and cell proliferation (respectively, 60% and 63%) and induced apoptosis in 75% of cells. These effects were abolished by co-treatment with GW9662 and blunted in PPAR knockdown cells. Contrarily to etoposide, similar inhibitory effects of GW9662 were obtained in HT-29 cells treated with rosiglitazone. In the xenograft model, GW9662 abolished the therapeutic effect of 5-ASA, which decreased tumor weight and volume by 80% in SCID mice compared with untreated mice. In A/JOlaHsd mice, 5-ASA suppressed colon carcinogenesis by decreasing the number of aberrant crypt foci (75%) and aberrant crypts (22%) induced by AOM treatment with an absence of 5-ASA response after GW9662 administration. In conclusion, 5-ASA exerts potent antineoplastic effects that are mediated through PPARγ. These data provide new rational for designing more effective and safe antineoplastic PPARγ ligands with topical effects.

The new prophylactic strategy for colon cancer in inflammatory bowel disease by modulating microbiota

It is well understood that intestinal microbiota play an important role in the pathogenesis of inflammatory bowel disease (IBD). In addition, IBD patients are well known to have a higher risk of developing colon cancer due to chronic inflammation. Recent evidence suggests that manipulation of microbiota improves the clinical outcome of patients with IBD and may reduce onset of colon cancer without obvious toxicity. This review summarizes the current experimental and clinical knowledge about the role of intestinal microbiota in IBD and colon cancer, and the nutraceutical therapy for colon cancer.

Higher apoptosis index and proliferation index in colonocytes of patients with ulcerative colitis in remission

Ulcerative colitis (UC) is a inflammatory disease of large bowel. The amount of people suffering from UC increases from year to year. Pathogenesis of this affection is still not entirely clear. Mechanisms of proliferation and apoptosis in colonocytes in the course of the disease are defected.

THE AIM OF THE STUDY

was to assess the rate of proliferation and intensity of apoptosis in colonocytes in patients with diagnose UC.

MATERIAL AND METHODS

Colon pathological samples taken from patients with diagnosed ulceraive colitis were examined. Patients were in both clinical and endoscopic remission and were treated with mesalazin. They were patient of Department of General and Colorectal Surgery. To estimate proliferation index dye with monoclonal antibody against Ki67. To determine apoptosis level immunohistochemistry with antybody against Bax was used.

RESULTS

Average Ki-67 in the test group was 42,13%, the largest value amounted to 57% and the lowest of 33%. Average value of Bax was 1.47 and ranged between 0-3. High index of bax appear not only in the bottom of the crypt, but also at their outlet.

CONCLUSIONS

In ulecerative colitis genetic and immunological disturbances occur despite treatment. Mesalazine acting only on certain routes associated with the UC holds the remission, without, however "the molecular remission". Thus, it appears that the results of our research are another proof of the necessary caution in weaning support treatment.

Colorectal cancer chemoprevention by mesalazine and its derivatives

Patients with inflammatory bowel disease (IBD) face an increased lifetime risk of developing colorectal cancer (CRC). Independent factors associated with increased risk include long disease duration, extensive colonic involvement, young age at onset of IBD, severity of inflammation, primary sclerosing cholangitis, backwash ileitis, and a family history of CRC, thus emphasising the role of intestinal inflammation as an underlying mechanism. This notion is also supported by the demonstration that the use of certain drugs used to attenuate the ongoing mucosal inflammation, such as mesalazine, seems to associate with a reduced incidence of colitis-associated CRC. In the last decade, work from many laboratories has contributed to delineate the mechanisms by which mesalazine alters CRC cell behaviour. In this paper, we review the available experimental data supporting the ability of mesalazine and its derivatives to interfere with intracellular signals involved in CRC cell growth.

Ulcerative colitis impairs the acylethanolamide-based anti-inflammatory system reversal by 5-aminosalicylic acid and glucocorticoids

Studies in animal models and humans suggest anti-inflammatory roles on the N-acylethanolamide (NAE)-peroxisome proliferators activated receptor alpha (PPARα) system in inflammatory bowel diseases. However, the presence and function of NAE-PPARα signaling system in the ulcerative colitis (UC) of humans remain unknown as well as its response to active anti-inflammatory therapies such as 5-aminosalicylic acid (5-ASA) and glucocorticoids. Expression of PPARα receptor and PPARα ligands-biosynthetic (NAPE-PLD) and -degrading (FAAH and NAAA) enzymes were analyzed in untreated active and 5-ASA/glucocorticoids/immunomodulators-treated quiescent UC patients compared to healthy human colonic tissue by RT-PCR and immunohistochemical analyses. PPARα, NAAA, NAPE-PLD and FAAH showed differential distributions in the colonic epithelium, lamina propria, smooth muscle and enteric plexus. Gene expression analysis indicated a decrease of PPARα, PPARγ and NAAA, and an increase of FAAH and iNOS in the active colitis mucosa. Immunohistochemical expression in active colitis epithelium confirmed a PPARα decrease, but showed a sharp NAAA increase and a NAPE-PLD decrease, which were partially restored to control levels after treatment. We also characterized the immune cells of the UC mucosa infiltrate. We detected a decreased number of NAAA-positive and an increased number of FAAH-positive immune cells in active UC, which were partially restored to control levels after treatment. NAE-PPARα signaling system is impaired during active UC and 5-ASA/glucocorticoids treatment restored its normal expression. Since 5-ASA actions may work through PPARα and glucocorticoids through NAE-producing/degrading enzymes, the use of PPARα agonists or FAAH/NAAA blockers that increases endogenous PPARα ligands may yield similar therapeutics advantages.

Chemopreventive effects of NSAIDs as inhibitors of cyclooxygenase-2 and inducers of apoptosis in experimental lung carcinogenesis

Roles of cyclooxygenase (COX) enzyme and intrinsic pathway of apoptosis have been explored for the chemopreventive effects of non-steroidal anti-inflammatory drugs (NSAIDs) on 9,10-dimethyl benz(a)anthracene (DMBA)-induced lung cancer in rat model. 16 weeks after the administration of DMBA, morphological analysis revealed the occurrences of tumours and lesions, which were regressed considerably with the co-administration of indomethacin and etoricoxib, the two NSAIDs under investigation. DMBA group was marked by hyperplasia and dysplasia as observed by histological examination, and these features were corrected to a large extent by the two NSAIDs. Elevated levels of COX-2 were seen in the DMBA group, the enzyme responsible for prostaglandin synthesis during inflammation and cancer, whilst the expression of the constitutive isoform, COX-1, was equally expressed in all the groups. Apoptosis was quantified by studying the activities of apaf-1, caspase-9, and 3 by immunofluorescence and western blots. Their activities were found to diminish in the DMBA-treated animals as compared to the other groups. Fluorescent co-staining of the isolated broncho-alveolar lavage cells showed reduced number of apoptotic cells in the DMBA group, indicating decrease in apoptosis after carcinogen administration. The present results thus suggest that the mechanism of cancer chemoprevention of NSAIDs may include the suppression of COX-2 and the induction of apoptosis.

Acute sensitization of colon cancer cells to inflammatory cytokines by prophase arrest

Understanding how colon cancer cells survive within the inflammatory milieu of a tumor, and developing approaches that increase their sensitivity to inflammatory cytokines, may ultimately lead to novel approaches for colon cancer therapy and prevention. Analysis of a number of chemopreventive and therapeutic agents reveal that HDAC inhibitors are particularly adept at sensitizing colon cancer cells TNF or TRAIL mediated apoptosis. In vivo data are consistent with an interaction between SAHA and TNF in inducing apoptosis, as AOM-induced colon tumors express elevated levels of TNF and are more sensitive to SAHA administration. Cell cycle analysis and time-lapse imaging indicated a close correspondence between SAHA-induced prophase arrest and TNF or TRAIL-induced apoptosis. Prophase arrest induced by the Aurora kinase inhibitor VX680 likewise sensitized cells to TNF and TRAIL, with siRNA analysis pointing to Aurora kinase A (and not Aurora kinase B) as being the relevant target for this sensitization. We propose that agents that promote prophase arrest may help sensitize cancer cells to TNF and other inflammatory cytokines. We also discuss how circumvention of an early mitotic checkpoint may facilitate cancer cell survival in the inflammatory micro-environment of the tumor.

The influence of 5-aminosalicylic acid on the progression of colorectal adenomas via the β-catenin signaling pathway

Surveillance colonoscopy is an important strategy for prevention of colorectal cancer. 5-aminosalicylate (ASA) (mesalazine) is discussed as a chemopreventive agent as it reduces the cancer risk in ulcerative colitis patients. The current study analyses the effect of 5-ASA on Wnt/β-catenin signaling in vitro and in vivo in colon epithelial cells. The effect of 5-ASA was determined using a β-catenin/T-cell factor (TCF)-reporter assay and by western blotting in cultured colon cancer cells. Formalin fixed paraffin embedded material from 227 polyps removed from a subgroup of 56 patients, who participated in a randomized placebo-controlled 3-year prevention trial with 5-ASA was evaluated according to histomorphological characteristics and expression of β-catenin and target genes Cox2, cyclin D1 and E-cadherin as well as ornithine decarboxylase (ODC). Patients were grouped into a low-risk and a high-risk group according to the number of adenomas at initial colonoscopy. ß-catenin/TCF signaling activity was significantly reduced by 5-ASA treatment possibly through a reduction in ß-catenin levels. Moreover, 5-ASA significantly reduced ß-catenin levels and nuclear localization in patients' adenomas. In addition, 5-ASA also significantly changed expression of the downstream targets Cox2, cyclin D1 and E-cadherin, correlating with ß-catenin status. Moreover, 5-ASA significantly reduced levels of ODC in vivo. Expression of p53 was unaltered by the 5-ASA treatment. Our study shows a significant in vitro and long-term in vivo effect of 5-ASA on ß-catenin signaling as a key signaling pathway in the development of colorectal adenoma. Therefore, we suggest the use of 5-ASA as a promising drug for prevention of sporadic colorectal carcinoma.

Current management of inflammatory bowel disease and colorectal cancer

INFLAMMATORY BOWEL DISEASES (IBDS) CAN BE DIVIDED INTO TWO MAJOR DISORDERS: ulcerative colitis and Crohn's disease. Although IBD-associated colorectal cancer (IBD-CRC) accounts for only 1-2% of all cases of colorectal cancer, IBD with colon involvement is among the top three high-risk conditions for colorectal cancer. Today, colorectal cancer accounts for approximately 10-15% of all deaths among IBD patients. Indeed, patients with IBD colitis are six times more likely to develop colorectal cancer than the general population and have a higher frequency of multiple synchronous colorectal cancers. Since IBD-CRC was first described in 1925, the colon remains the primary site of neoplasms in IBD patients today. Ulcerative colitis-associated colorectal cancer is most common in the rectum and sigmoid colon, whereas Crohn's disease-associated colorectal cancer is evenly distributed between the different colon segments. Chemoprevention of colorectal cancer remains an important goal, and colonoscopy surveillance programs are critical to early detection in these patients. Newer methods, such as chromoendoscopy, are currently being investigated as complementary techniques to enhance early detection of dysplasia and cancer in this high-risk population. We present a comprehensive review of the relationship between inflammatory bowel disease and colorectal cancer. Major themes covered include risk factors for IBD-CRC and the molecular pathobiology of progression from dysplasia to cancer, endoscopic surveillance and new methods for early detection of dysplasia, approaches to prevention of IBD-CRC, and current recommendations and controversies regarding the treatment of dysplasia. In particular, disagreement has arisen over optimal management of low-grade dysplasia, with some IBD experts now advocating close colonoscopic surveillance of patients with low-grade dysplasia rather then total colectomy.

The actin-bundling protein fascin is overexpressed in inflammatory bowel disease and may be important in tissue repair

BACKGROUND

Fascin is associated with increased cell motility in colorectal tumours but is absent from the normal colonic epithelium. We examined the expression of fascin in inflammatory bowel disease (IBD) and its location at regions undergoing restitution and regeneration. Tissue repair is essential for disease remission and we sought to determine the effects of therapeutic modalities on fascin expression and function using an in vitro model.

METHODS

Immunohistochemistry was performed on colonic tissue from IBD patients to determine changes in fascin expression and distribution. A human colorectal epithelial cell line was treated with 5-aminosalicylate (a common treatment for IBD), or sodium butyrate to determine the effect on fascin expression and cell motility.

RESULTS

Fascin overexpression was observed in both ulcerative colitis and Crohn's colitis and expression correlated with disease severity. Immunoreactivity was more intense and widespread in Crohn's compared to ulcerative colitis. Interestingly, highly expressing foci were consistently observed at the edges of ulcers where flattened, motile epithelial cells are actively involved in restitution, and also in areas of mucosal regeneration.5-aminosalicylate reduced fascin expression in colorectal epithelial cells and inhibited their motility. Conversely, sodium butyrate increased fascin expression and stimulated cell motility in the same cells.

CONCLUSIONS

Our data shows that fascin is overexpressed in inflammatory bowel disease and its location is indicative of a role in tissue repair. Our in vitro studies show that different therapeutic modalities may have converse effects on fascin expression and may have significant consequences for disease remission and the clinical management of IBD.

The position of the amino group on the benzene ring is critical for mesalamine's improvement of replication fidelity

BACKGROUND

Individuals with ulcerative colitis are at high risk of developing colitis-associated cancer. 5-Aminosalicylate (5-ASA) protects from cancer by its antiinflammatory activity as well as by altering cell growth, inducing apoptosis, and reducing replication errors. So far neither 5-ASA's structural specificity nor its pharmacophore group have been identified. Here we compared 5-ASA with its analogs (4-ASA and 3-ASA) and its metabolite N-acetyl-5-ASA (NAc-5-ASA).

METHODS

Superoxide scavenging was analyzed by lucigenin-amplified chemiluminescence. Cell growth, cell cycle distribution, and replication fidelity at a (CA)13 microsatellite were measured in HCT116 and HT29 colon epithelial cells by MTT and flow cytometry. Nuclear protein extracts were blotted for replication protein A (RPA), claspin, p53, and p53(Ser15).

RESULTS

All compounds inhibited the growth of colon epithelial cells at a similar level and displayed potent scavenging properties, with 3-ASA being the most active, followed by 5-ASA, 4-ASA, and NAc-5-ASA. Besides 5-ASA, only 4-ASA caused an increase in the S-phase population (56%-69% and 49%-62% in HCT116 and HT29 cells, respectively). This was accompanied by nuclear recruitment of replication proteins RPA and claspin as well as phosphorylation of p53(Ser15), both of which were weaker or absent with 3-ASA or NAc-5-ASA. 5-ASA was the only compound that lowered mutations at a (CA)13 microsatellite.

CONCLUSIONS

5-ASA shares its growth inhibitory and superoxide scavenging properties with its structural analogs and metabolite, but the position of the amino group is critical for reducing replication errors.

Mesalazine reduces mutations in transforming growth factor beta receptor II and activin type II receptor by improvement of replication fidelity in mononucleotide repeats

PURPOSE

Mesalazine (5-aminosalicylic acid, 5-ASA) has chemopreventive properties in colitis-associated cancer. In vitro, it improves replication fidelity at (CA)13 microsatellites independent of mismatch repair proficiency. Therefore, 5-ASA might be advantageous in patients with hereditary nonpolyposis colorectal cancer. At this point, however, it is uncertain whether this improvement of replication fidelity is specific for (CA)13 repetitive sequences. Here, we tested the effect of 5-ASA on replication fidelity in mononucleotide, dinucleotide, and tetranucleotide repeats.

EXPERIMENTAL DESIGN

HCT116 and HCT116+chr3 cells were transfected with pIREShyg2-EGFP reporter plasmids harboring the following microsatellites: A10, G10, (CA)13, (CA)26, (AAAG)17, poly-A tracts, and their flanking sequences of transforming growth factor beta receptor II (TGFBR2; A10) and activin type II receptor (ACVR2; A8). Stably transfected single-cell clones were selected, characterized by Southern blotting, sorted into six-well plates, and cultured with or without 5-ASA. Frameshift mutations that shift the enhanced green fluorescence protein into its proper reading frame were quantified by flow cytometry.

RESULTS

In HCT116, 5-ASA reduced the mutant fraction at (CA)13 by 48.3%, at A10 by 35.6-43.6%, at G10 by 74.9-83.6%, and at (AAAG)17 by 37.6-44.4%. Similar results were observed in hMLH1-proficient HCT116+chr3 cells. Moreover, the presence of 5-ASA significantly reduced mutations in TGFBR2 (A10) and ACVR2 (A8) by 39.9% and 46.2%, respectively.

CONCLUSIONS

5-ASA increases replication fidelity in mononucleotide, dinucleotide, and tetranucleotide repeats and reduces mutations in tumor suppressor genes TGFBR2 and ACVR2, a finding that may provoke in vivo studies for the prevention of colorectal cancer in hereditary nonpolyposis colorectal cancer.

5-aminosalicylic acid interferes in the cell cycle of colorectal cancer cells and induces cell death modes

INTRODUCTION

Epidemiological data suggests that 5-aminosalicylic acid (5-ASA), a nonsteroidal antiinflammatory drug used in the treatment of inflammatory bowel diseases, prevents colorectal cancer development in these patients, although the mechanisms remain incompletely understood.

METHODS AND RESULTS

Here we report that 5-ASA prevents growth of several colorectal cancer cell lines by interfering in the cell cycle, i.e., an S-phase and G2/M phase arrest, dependent on 5-ASA dosage and concentration, together with an increased mitotic index. In addition, prolonged cell cycle arrest by repeated 5-ASA treatment induced apoptosis and caused abnormal spindle organization leading to mitotic catastrophe, another form of cell death.

CONCLUSION

These observations illustrate that 5-ASA has chemopreventive and chemotherapeutic properties.

Mesalazine inhibits the beta-catenin signalling pathway acting through the upregulation of mu-protocadherin gene in colo-rectal cancer cells

BACKGROUND

Several reports indicate that mesalazine (5-aminosalicylic acid, 5-ASA) is a promising candidate for the chemoprevention of colo-rectal cancer because of its ability to reach the purpose avoiding the unwanted side effects usually associated with prolonged administration of nonsteroidal anti-inflammatory drugs. This activity of 5-ASA is probably the consequence of a number of effects determined on colo-rectal cancer cells, consisting of reduced proliferation, increased apoptosis and activation of cell cycle checkpoints and DNA repair processes. A recent observation has suggested that inhibition of beta-catenin signalling could induce these cellular effects.

AIM

To characterize better the capacity of 5-ASA to inhibit the beta-catenin signalling pathway.

METHODS

Genes belonging to the beta-catenin signalling pathway were analysed in colo-rectal cancer cell lines treated with 5-ASA using a combination of laboratory assays that are able to detect their phenotypic expression and functional activity.

RESULTS

The results obtained indicated that 5-ASA induces the expression of a protein called mu-protocadherin that belongs to the cadherin superfamily and is able to sequester beta-catenin on the plasmatic membrane of treated cells hampering its function.

CONCLUSION

These findings suggest that mu-protocadherin might be employed as a biological marker to monitor the chemopreventive efficacy of 5-ASA.

In vivo effects of mesalazine or E. coli Nissle 1917 on microsatellite instability in ulcerative colitis

BACKGROUND

Microsatellite instability (MSI) occurs in chronically inflamed colorectal tissue and may evolve to colitis-associated cancer. In vitro data suggest that mesalazine (5-ASA) improves MSI.

AIM

To analyse the changes in MSI in 156 distal colonic biopsies of 39 patients with ulcerative colitis that had been treated within a randomized, double-blind trial comparing 5-ASA with E. coli Nissle (EcN).

METHODS

Two biopsies had been collected before and after 1 year of treatment. MSI testing was performed using a panel of eight markers, including 3 dinucleotide and 5 mononucleotide repeats.

RESULTS

No MSI was observed with any of the mono-repeats, and among dinucleotide repeats, only D5S346 (maps to APC) and D17S250 (p53) were consistently informative. Overall, 31/156 (20%) biopsies displayed MSI. After 1 year, 3/11 patients displayed MSI improvement [change to microsatellite stability (MSS); 1 on 5-ASA, 2 on EcN] at D5S346 and 4/11 showed MSI worsening (change from MSS to MSI; all 5-ASA). For D17S250, the corresponding data were for 3/9 patients (2 on 5-ASA, 1 on EcN) and 2/9 (both on 5-ASA), respectively.

CONCLUSIONS

In the set of biopsies taken from patients treated with 1.5 g 5-ASA for 1 year, there was no improvement in the prevalence of MSI in the distal colon.

Influence of standard treatment on ileal and colonic antimicrobial defensin expression in active Crohn's disease

BACKGROUND

Crohn's Disease (CD), a chronic intestinal inflammation, is currently treated primarily by therapeutics which are directed against inflammatory responses. Recent findings though suggest a central role of the innate immune barrier in the pathophysiology. Important factors providing this barrier are antimicrobial peptides like the alpha- and beta-defensins. Little is known about in vivo effects of common drugs on their expression.

AIM

To analyse the influence of corticosteroids, azathioprine and aminosalicylate treatment on ileal and colonic antimicrobial peptides in active CD and also assess the role of inflammation.

METHODS

We measured the expression of antimicrobial peptides and pro-inflammatory cytokines in 75 patients with active CD.

RESULTS

Ileal and colonic alpha- and beta-defensins as well as LL37 remained unaffected by corticosteroids, azathioprine or aminosalicylate treatment. Additionally, we did not observe a negative coherency between Paneth cell alpha-defensins and any measured cytokines. HBD2 and LL37 unlike HBD1 levels were linked to inflammatory cytokines and increased in highly inflamed samples.

CONCLUSIONS

Current oral drug treatment seems to have no major effect on the expression of antimicrobial peptides. In contrast to HBD2 and LL37, ileal levels of HD5 and HD6 and colonic HBD1 level are independent of current inflammation. Innovative drugs should aim to strengthen protective innate immunity.

Cost effectiveness of ulcerative colitis surveillance in the setting of 5-aminosalicylates

OBJECTIVES

Colorectal cancer (CRC) is a feared complication of chronic ulcerative colitis (UC). Annual endoscopic surveillance is recommended for the detection of early neoplasia. 5-Aminosalicylates (5-ASAs) may prevent some UC-associated CRC. Therefore, in patients prescribed 5-ASAs for maintenance of remission, annual surveillance might be overly burdensome and inefficient. We aimed to determine the ideal frequency of surveillance in patients with UC maintained on 5-ASAs.

METHODS

We performed systematic reviews of the literature, and created a Markov computer model simulating a cohort of 35-year-old men with chronic UC, followed until the age of 90 years. Twenty-two strategies were modeled: natural history (no 5-ASA or surveillance), surveillance without 5-ASA at intervals of 1-10 years, 5-ASA plus surveillance every 1-10 years, and 5-ASA alone. The primary outcome was the ideal interval of surveillance in the setting of 5-ASA maintenance, assuming a third-party payer was willing to pay $100,000 for each quality-adjusted life-year (QALY) gained.

RESULTS

In the natural history strategy, the CRC incidence was 30%. Without 5-ASA, annual surveillance was the ideal strategy, preventing 89% of CRC and costing $69,100 per QALY gained compared with surveillance every 2 years. 5-ASA alone prevented 49% of CRC. In the setting of 5-ASA, surveillance every 3 years was ideal, preventing 87% of CRC. 5-ASA with surveillance every 2 years cost an additional $147,500 per QALY gained, and 5-ASA with annual surveillance cost nearly $1 million additional per QALY gained compared with every 2 years. In Monte Carlo simulations, surveillance every 2 years or less often was ideal in 95% of simulations.

CONCLUSIONS

If 5-ASA is efficacious chemoprevention for UC-associated CRC, endoscopic surveillance might be safely performed every 2 years or less often. Such practice could decrease burdens to patients and on endoscopic resources with a minimal decrease in quality-adjusted length of life, because 5-ASA with annual surveillance may cost nearly $1 million per additional QALY gained.

NC2213: a novel methionine aminopeptidase 2 inhibitor in human colon cancer HT29 cells

Methionine aminopeptidase 2 (MetAP2) is a bifunctional protein that plays a critical role in the regulation of post-translational processing and protein synthesis. MetAP2 is overexpressed in human colon cancer. In this report we screened various MetAP2 inhibitors and treated HT29 cells with various concentrations of compounds. We evaluated the expression of MetAP2 and pp60c-src expressions in HT29 cells. In addition we also carried out the cell proliferation and cell cycle analysis in the MetAP2 inhibitor-treated HT29 cells. The cell cycle analysis of HT29 treated with 1.0 microM of NC2213 showed an arrest in the G2 phase followed by an induction in the percentage of cells undergoing apoptosis in the sub-G1 phase. Western blot analysis revealed that the MetAP2 expression was dose-dependently decreased when the HT29 cells were treated with the 3,5-bis(benzylidene)-4-piperidone derivative (NC2213). In addition, phosphorylation of Src, a myristoylated oncoprotein was significantly decreased by 1.0 microM of NC2213 as revealed by Western blot analysis. Furthermore, NC2213 also inhibits the expression of pp60c-src in HT29 cells. Interestingly, this compound also inhibits the phosphorylation at Tyr416 of pp60c-src while increasing the phosphorylation at Tyr527 of pp60c-src. NC2213 inhibits the growth of HT29 cells by inducing apoptosis and might be useful for the treatment of human colon cancer.

Mesalamine suppresses the expression of TC22, a novel tropomyosin isoform associated with colonic neoplasia

Although a protective role for mesalamine against colon cancer in ulcerative colitis has been shown epidemiologically, its molecular mechanism is unknown. We cloned and sequenced a novel human tropomyosin (hTM) isoform, TC22, which is an alternatively spliced variant of normal epithelial hTM isoform 5 (hTM5), identical apart from 25 C-terminal amino acids. TC22 is expressed in 100% of colorectal carcinoma but is not expressed in normal colon epithelial cells. To explore a molecular mechanism of chemoprevention, we examined the effect of mesalamine on TC22 expression using LS180 colon cancer cells. Expression of hTM5 and TC22 was investigated at the protein and gene levels by fluorescence-activated cell sorting and real-time reverse transcription-polymerase chain reaction. Small interference RNA (siRNA) against the TC22 variant were transfected into LS180 colon cancer cells, reducing protein and transcript levels by 45 to 50%. Mesalamine or sulfasalazine (2 mM), but not sulfapyridine, significantly (p < 0.02-0.006) reduced the expression of the TC22 transcript and significantly (p < 0.05 to <0.0002) reduced the expression of TC22 protein in a dose-dependent and reversible manner. Rosiglitazone, a specific peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist, similarly and significantly (p < 0.002) reduced TC22 protein expression. A polymerase chain reaction array of 84 cancer-related genes performed on TC22 siRNA-transfected cells demonstrated a significant (more than two times) change in targets involved in apoptosis, adhesion, angiogenesis, and tissue remodeling. We conclude that mesalamine, sulfasalazine, and rosiglitazone significantly reduced the cellular expression of TC22, implicating PPARgamma in this modulation. Similar suppression of TC22 by siRNA produced gene level changes on several critical carcinogenic pathways. These findings suggest a novel antineoplastic molecular effect of mesalamine.

5-Aminosalicylic acid inhibits TGF-beta1 signalling in colorectal cancer cells

The transforming growth factor-beta (TGF-beta) pathway is an important pathway in the initiation and progression of colorectal cancer. We aimed to determine the effects of 5-aminosalicylic acid (5-ASA) on TGF-beta signalling in colorectal cancer cells in vitro. 5-ASA inhibited TGF-beta1 signalling in HCT116 cells and colonic fibroblasts, as judged by a TGF-beta-specific reporter gene assay, plasminogen activator inhibitor-1 mRNA and protein levels, fibroblast trans-differentiation, Smad3 phosphorylation and nuclear translocation. We conclude that 5-ASA inhibits TGF-beta1 signalling in colorectal cancer cells, and might be a potent adjuvant therapeutic drug, interfering with aberrant TGF-beta signalling in colorectal cancer.

5-Aminosalicylic acid inhibits colitis-associated but not sporadic colorectal neoplasia in a novel conditional Apc mouse model

Genetic predisposition, life-style habits and inflammatory bowel diseases (IBD)-related colitis are a main risk factor for colorectal cancer (CRC). 5-Aminosalicylic acid (5-ASA, mesalazine) is a mainstay therapy in IBD and believed to reduce the risk for developing CRC. We aimed to determine the ability of 5-ASA enemas to inhibit the development of sporadic and colitis-related neoplasia in mice. FabplCre;Apc(15lox/+) mice, which spontaneously develop sporadic colorectal tumours, were treated at 5 weeks of age with 5-ASA or placebo enemas for 3 weeks and examined for colorectal tumourigenesis at 8 weeks of age. Colitis-related tumour development was investigated in these mice by administration of dextran sodium sulphate, inducing intestinal inflammation and accelerating colorectal tumourigenesis, combined with treatment of 5-ASA or placebo enemas during and/or after colitis induction. 5-ASA significantly reduced colitis-accelerated neoplasia development by 50%, from 19.4 +/- 2.7 to 9.4 +/- 2.4 (mean tumour numbers +/- SEM, P = 0.02), in the distal part of the large intestine covered by the enema. 5-ASA was only effective when given during and/or after the intestinal inflammatory period. 5-ASA did not reduce, however, sporadic neoplasia development in the FabplCre;Apc(15lox/+) mice. 5-ASA tended to reduce proliferation of epithelial cells in the colitis-associated colorectal tumours but not in the sporadic colorectal tumours. In conclusion, 5-ASA medication inhibits the development of colitis-associated tumours in FabplCre;Apc(15lox/+) mice when administered during and/or after the induction of inflammation. 5-ASA does not reduce, however, sporadic tumour development in this mouse model.

Systematic review: does concurrent therapy with 5-ASA and immunomodulators in inflammatory bowel disease improve outcomes?

BACKGROUND

With greater use of immunomodulators in inflammatory bowel disease (IBD), it is uncertain whether concurrent therapy with both 5-aminosalicylic acid [5-ASA, mesalazine (mesalamine)] and an immunomodulator is necessary.

AIM

To determine whether concurrent therapy with both 5-ASA and immunomodulator(s) improves outcomes in IBD.

METHODS

Systematic review with search terms 'azathioprine, 6-mercaptopurine, thiopurine(s), 5 aminosalicylic acid, mesalazine, inflammatory bowel disease, ulcerative colitis, Crohn's disease, immunosuppressant(s), immunomodulator and methotrexate' in November 2007 to identify clinical trials on concurrent 5-ASA and immunomodulator therapy.

RESULTS

Two small controlled studies were found. Neither showed a benefit on disease control beyond immunomodulator monotherapy. Potential pharmacological interactions exist between 5-ASA and thiopurines. Whilst circumstantial, epidemiological and laboratory evidence suggests that 5-ASA may assist colorectal cancer (CRC) chemoprevention, it may simply be via anti-inflammatory effects. With changes in practice, ethical issues and the long lead-time needed to demonstrate or disprove an effect, no clinical studies can/will directly answer this. The costs of avoiding one CRC in IBD may be as low as 153 times the annual cost of 5-ASA therapy.

CONCLUSIONS

It is unclear whether concurrent 5-ASA and immunomodulator therapy improves outcomes of disease control, drug toxicity or compliance. Concurrent therapy of 5-ASA and immunomodulators may decrease CRC risk at 'acceptable' cost.

Combined treatment of Caco-2 cells with butyrate and mesalazine inhibits cell proliferation and reduces Survivin protein level

There is epidemiological evidence, that mesalazine can inhibit colon cancer development by affecting proliferation and apoptosis. Several studies suggest that supplementary intake of butyrate may yield to improved efficacy of mesalazine. However, the underlying molecular mechanisms of such interaction remain unknown. This study addressed the combinatory effect of both substances on the growth of Caco-2 cells. Challenging of cells with mesalazine and butyrate provoked a time-dependent decrease in both cell counts and proliferation. Co-treatment with the substances could further intensify these effects. The growth-inhibitory action of mesalazine and butyrate was accompanied by a significant increase in caspase-3 activity, cleavage of PARP and caspase-8, while decreasing the expression of Xiap and Survivin simultaneously. Co-incubation of both substances exaggerated effects on all examined apoptosis-regulatory proteins except for Xiap. Our data demonstrate that co-treatment of mesalazine and butyrate evoked additive effects on inhibition of cell growth and induction of apoptosis in Caco-2 cells.

5-aminosalicylic acid inhibits colitis-associated colorectal dysplasias in the mouse model of azoxymethane/dextran sulfate sodium-induced colitis

BACKGROUND

The impact of the antiinflammatory agent 5-aminosalicylic acid (5-ASA) on the risk for colitis-associated colorectal cancer remains controversial. The chemopreventive activity of 5-ASA was evaluated in the Swiss Webster model of azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colitis-associated neoplasia.

METHODS

Mice were injected with AOM (7.4 mg/kg i.p.) and randomized to receive either vehicle or 5-ASA (75, 150, and 225 mg/kg) for the remainder of the study. DSS treatment began at 9 weeks of age and continued for 3 cycles. At the time of sacrifice (18 weeks of age), the entire colon and rectum were processed for histopathologic examination.

RESULTS

An inverse trend was observed between dose and multiplicity of colonic dysplasias in all drug-treated groups (P = 0.03), with animals receiving 75 mg/kg 5-ASA exhibiting 56% of the number of dysplasias of the AOM/DSS controls (mean +/- SEM: 7.6 +/- 1.4 and 13.6 +/- 2.7, respectively). Administration of 75 mg/kg 5-ASA decreased both the mean multiplicity of flat dysplasias (1.8 +/- 0.4 for drug-treated versus 5.6 +/- 1.2 for AOM/DSS control) and the burden of polypoid dysplasias (tumor burden: 6.7 +/- 2.7 for drug-treated versus 14.9 +/- 3.9 units for AOM/DSS controls) significantly (P = 0.002 and 0.04, respectively). Inflammation was least severe in the 75 mg/kg group, which exhibited the fewest number of colorectal tumors.

CONCLUSIONS

These data suggest that low-dose 5-ASA may be efficacious in preventing colitis-associated dysplasias and provide strong support for optimizing this therapy for the prevention of colonic neoplasms in patients with ulcerative colitis.

Effect of mesalazine on epithelial cell proliferation in colonic diverticular disease

BACKGROUND AND AIMS

Increased epithelial cell proliferation may be detected in diverticular disease, but antibiotics have failed in reducing it. We assess therefore the effect of mesalazine on epithelial cell proliferation in diverticular disease.

METHODS

A prospective study was conducted on 20 consecutive patients with a new endoscopic diagnosis of symptomatic uncomplicated diverticular disease. The patients were treated with mesalazine 1.6 mg/day for 1 year. The Ki-67 antigen index of the whole crypt and in the upper third was separately evaluated before and after starting the treatment.

RESULTS

Cell proliferation index was higher in diverticular disease patients than healthy controls both in the whole crypt (median 6.7%, range 2-9% vs. median 1.6%, range 1-3%, p=0.001) and in the upper third of the crypt (median 6.8%, range 2-8% vs. median 1.8%, range 1-3%, p=0.001). Cell proliferation decreased throughout the follow-up. In the whole crypt it was 6.7% at entry and 3.8% at the end of treatment (p<0.005), whereas it was 6.8% at entry and 2.9% at the end of treatment in the upper third of the crypt (p<0.005).

CONCLUSIONS

We found mesalazine effective in reducing the colonic cell proliferation in long-term treatment for colonic diverticular disease.

Molecular basis of the potential of mesalazine to prevent colorectal cancer

Patients with ulcerative colitis (UC) and Crohn's disease (CD) are at increased risk for developing colorectal cancer (CRC), and this is believed to be a result of chronic inflammation. Although conclusive evidence is still missing, both epidemiological and experimental observations suggest that certain drugs used to treat inflammation, such as mesalazine, can reduce the incidence of colitis-associated CRC. Therefore, in recent years, several studies have been conducted to dissect the mechanisms by which mesalazine interferes with CRC cell growth and survival. This review summarizes the current information on the molecular mechanisms that underlie the antineoplastic action of mesalazine.

PPARgamma is involved in mesalazine-mediated induction of apoptosis and inhibition of cell growth in colon cancer cells

PURPOSE

Mesalazine has been identified as a candidate chemopreventive agent in colon cancer prophylaxis because of its pro-apoptotic and anti-proliferative effects. However, the precise mechanisms of action are not entirely understood. The aim of our study was to investigate the involvement of peroxisome proliferator-activated receptor gamma (PPARgamma) in mesalazine's anticarcinogenic actions in colorectal cancer cells.

EXPERIMENTAL DESIGN

The effects of mesalazine on cell cycle distribution, cell count, proliferation and caspase-mediated apoptosis were examined in Caco-2, HT-29 and HCT-116 cells used as wild-type, dominant-negative PPARgamma mutant and empty vector cultures. We focused on caspase-3 activity, cleavage of poly(ADP-ribose) polymerase (PARP), caspase-8 and caspase-9, as well as on expression of survivin, X-linked inhibitor of apoptosis (Xiap), phosphatase and tensin homolog deleted from chromosome ten (PTEN) and c-Myc. Techniques employed included transfection assays, immunoblotting, flow cytometry analysis, colorimetric and fluorometric assays.

RESULTS

Mesalazine caused a time- and dose-dependent decrease in both cell growth and proliferation. Growth inhibition was accompanied by a G1/G0 arrest, a significant increase in PTEN, caspase-3 activity, cleavage of PARP and caspase-8, whereas the expressions of Xiap, survivin and c-Myc were decreased simultaneously. Cleavage of caspase-9 was not observed. Moreover, PPARgamma expression and activity were elevated. The growth-inhibitory effect of mesalazine was partially reduced in dominant-negative PPARgamma mutant cells, whereas the expression of c-Myc was not affected. Mesalazine-mediated increased caspase-3 activity, the expression of PTEN, cleavage of PARP and caspase-8 as well as reduced levels of survivin and Xiap were completely abolished in the PPARgamma mutant cell lines.

CONCLUSION

This study clearly demonstrates that mesalazine-mediated pro-apoptotic and anti-proliferative actions are regulated via PPARgamma-dependent and -independent pathways in colonocytes.

VSL#3 probiotic upregulates intestinal mucosal alkaline sphingomyelinase and reduces inflammation

BACKGROUND

Alkaline sphingomyelinase, an enzyme found exclusively in bile and the intestinal brush border, hydrolyzes sphingomyelin into ceramide, sphingosine and sphingosine-1-phosphate, thereby inducing epithelial apoptosis. Reduced levels of alkaline sphingomyelinase have been found in premalignant and malignant intestinal epithelia and in ulcerative colitis tissue. Probiotic bacteria can be a source of sphingomyelinase.

OBJECTIVE

To determine the effect of VSL#3 probiotic therapy on mucosal levels of alkaline sphingomyelinase, both in a mouse model of colitis and in patients with ulcerative colitis.

METHODS

Interleukin-10 gene-deficient (IL10KO) and wild type control mice were treated with VSL#3 (10(9) colony-forming units per day) for three weeks, after which alkaline sphingomyelinase activity was measured in ileal and colonic tissue. As well, 15 patients with ulcerative colitis were treated with VSL#3 (900 billion bacteria two times per day for five weeks). Alkaline sphingomyelinase activity was measured through biopsies and comparison of ulcerative colitis disease activity index scores obtained before and after treatment.

RESULTS

Lowered alkaline sphingomyelinase levels were seen in the colon (P=0.02) and ileum (P=0.04) of IL10KO mice, as compared with controls. Treatment of these mice with VSL#3 resulted in upregulation of mucosal alkaline sphingomyelinase activity in both the colon (P=0.04) and the ileum (P=0.01). VSL#3 treatment of human patients who had ulcerative colitis decreased mean (+/- SEM) ulcerative colitis disease activity index scores from 5.3+/-1.8946 to 0.70+/-0.34 (P=0.02) and increased mucosal alkaline sphingomyelinase activity.

CONCLUSION

Mucosal alkaline sphingomyelinase activity is reduced in the intestine of IL10KO mice with colitis and in humans with ulcerative colitis. VSL#3 probiotic therapy upregulates mucosal alkaline sphingomyelinase activity.