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

Therapeutic effect of 5-ASA and hesperidin-loaded chitosan/Eudragit® S100 nanoparticles as a pH-sensitive carrier for local targeted drug delivery in a rat model of ulcerative colitis

Ulcerative colitis (UC) is an idiopathic disease characterized by colonic mucosal tissue destruction secondary to an excessive immune response. We synthesized pH-sensitive cross-linked chitosan/Eudragit® S100 nanoparticles (EU S100/CS NPs) as carriers for 5-aminosalicylic acid (5-ASA) and hesperidin (HSP), then conducted in-vitro and in-vivo studies and evaluated the therapeutic effects. In-vitro analysis revealed that the 5-ASA-loaded EU S100/CS NPs and the HSP-loaded EU S100/CS NPs had smooth and curved surfaces and ranged in size between 250 and 300 nm, with a zeta potential of 32 to 34 mV. FTIR analysis demonstrated that the drugs were loaded on the nanoparticles without significant alterations. The loading capacity and encapsulation efficiency of loading 5-ASA onto EU S100/CS NPs were 25.13 % and 60.81 %, respectively. Regarding HSP, these values were 38.34 % and 77.84 %, respectively. Drug release did not occur in simulated gastric fluid (SGF), while a slow-release pattern was recorded for both drugs in simulated intestinal fluid (SIF). In-vivo macroscopic and histopathological examinations revealed that both NPs containing drugs significantly relieved the symptoms of acetic acid (AA)-induced UC in Wistar rats. We conclude that the synthesized pH-sensitive 5-ASA/EU S100/CS NPs and HSP/EU S100/CS NPs offer promise in treating UC.

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.

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.

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.

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.

Chemoprevention of colorectal cancer in ulcerative colitis: digging deep in current evidence

Patients with ulcerative colitis (UC) have an increased risk of developing colorectal cancer (CRC). Surveillance colonoscopy is currently recommended for patients with long-standing extensive colitis for reducing CRC risk. Chemoprevention is an attractive complementary strategy. Areas covered: Inflammation is a major determinant of CRC risk and is potentially modifiable. Reducing inflammation is supposed to reduce CRC risk. Several medications have been evaluated in this setting: 5-ASA, thiopurines, anti-TNFα agents and ursodeoxycholic acid (UCDA) in patients with associated primary sclerosing cholangitis (PSC). This review offers a critical evaluation of current evidence of the potential chemopreventive effect of such medications. Expert commentary: No randomized controlled trials have been performed and the available evidence come from observational studies. Although biological plausibility supports a chemopreventive role of the aforementioned agents, the overall evidence of efficacy is weak because of several methodological limitations of the studies. Indirect epidemiological evidence, biologic plausibility and results of meta-analyses reasonably support a potential chemopreventive effect of 5-ASA. Available evidence does not support a specific chemopreventive effect of purine analogues and anti-TNFα medications, despite their efficacy in the management of inflammatory bowel disease. Data addressing UDCA and folate supplementation are inconclusive. Limited data are available for statins.

Peroxisome proliferator-activated receptor-γ is downregulated in ulcerative colitis and is involved in experimental colitis-associated neoplasia

The aim of the present study was to evaluate the expression of peroxisome proliferator-activated receptor (PPAR)-γ in inflammatory bowel disease (IBD), and to also identify the association between PPAR-γ and the clinical features of patients with IBD. An azoxymethane (AOM)/dextran sodium sulfate (DSS) animal model of colitis-associated neoplasia was established to investigate the protective effect of 5-aminosalicylic acid (5-ASA) and to explore the changes in the expression of PPAR-γ during this process. A total of 66 specimens of colorectal tissue obtained from biopsy performed on IBD patients and 30 healthy control individuals were immunohistochemically stained for PPAR-γ. An AOM/DSS animal model of colitis-associated neoplasia was then established. Reverse transcription quantitative polymerase chain reaction was conducted and it was found that, compared with the control group and patients with Crohn's disease (CD), the expression of PPAR-γ in the intestinal tissue of patients with ulcerative colitis (UC) was significantly decreased (P=0.027 and 0.046, respectively). The expression of PPAR-γ was found to be negatively associated with the disease activity of UC and was not associated with the severity of disease, site of lesions or CD characteristics. Administration of 5-ASA decreased the colitis and tumor burden of colons. The expression level of PPAR-γ in the intestinal tissue was also increased in the AOM/DSS/5-ASA group compared with AOM/DSS group (P<0.001). PPAR-γ is an important factor in the pathogenesis of UC and colitis-associated cancer. The present study found that 5-ASA significantly alleviates the colitis and tumor burden in a mouse model of AOM/DSS-induced colitis-associated neoplasia, and promotes the expression of PPAR-γ in the intestinal tract.

Crystal structure of methyl 2-hy-droxy-5-[(4-oxo-4,5-di-hydro-1,3-thia-zol-2-yl)amino]benzoate

The title compound, C11H10N2O4S, crystallized with two independent mol-ecules (A and B) in the asymmetric unit. They differ primarily in the rotational orientation of the five-membered heterocyclic ring. In mol-ecule A this ring is inclined to the benzene ring by 48.17 (8)°, while in mol-ecule B the same dihedral angle is 23.07 (8)°. In each mol-ecule there is an intra-molecular O-H⋯O hydrogen bond involving the adjacent hydroxyl group and the ester carbonyl O atom. In the crystal, the A mol-ecules are linked via pairs of N-H⋯N hydrogen bonds, forming inversion dimers. These dimers are linked to the B mol-ecules via N-H.·O, C-H⋯O and C-H⋯S hydrogen bonds forming corrugated sheets lying parallel to (102).

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.

Mechanisms of action of non-steroidal anti-inflammatory drugs (NSAIDs) and mesalazine in the chemoprevention of colorectal cancer

Colorectal cancer (CRC) is the third most common malignant neoplasm worldwide. Although conclusive evidence is still lacking, epidemiologic studies suggest that long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) has chemopreventive properties against CRC. Similarly, regular consumption of mesalazine, a drug structurally related to NSAIDs, seems to reduce the risk of CRC in patients with ulcerative colitis. These observations are supported by a large body of experimental data showing the ability of such drugs to inhibit multiple pathways that sustain colon carcinogenesis. This review summarizes the current information on the molecular mechanisms by which NSAIDs and mesalazine could interfere with CRC cell growth and survival.

Mechanisms of action of non-steroidal anti-inflammatory drugs (NSAIDs) and mesalazine in the chemoprevention of colorectal cancer

Colorectal cancer (CRC) is the third most common malignant neoplasm worldwide. Although conclusive evidence is still lacking, epidemiologic studies suggest that long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) has chemopreventive properties against CRC. Similarly, regular consumption of mesalazine, a drug structurally related to NSAIDs, seems to reduce the risk of CRC in patients with ulcerative colitis. These observations are supported by a large body of experimental data showing the ability of such drugs to inhibit multiple pathways that sustain colon carcinogenesis. This review summarizes the current information on the molecular mechanisms by which NSAIDs and mesalazine could interfere with CRC cell growth and survival.

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.

Mesalamine in the treatment and maintenance of remission of ulcerative colitis

Ulcerative colitis (UC) is a chronic disease of the GI tract that is characterized by mucosal inflammation in the colon. Mesalamine (mesalazine) is a 5-aminosalicylic acid compound that is the first-line treatment for patients with mild-to-moderate UC. There are multiple formulations of mesalamine available, primarily differentiated by their means of delivering active mesalamine to the colon. Mesalamine has been demonstrated in randomized controlled trials to induce both clinical response and remission, and maintain clinical remission, in these patients. It has few serious adverse effects and is generally well tolerated by patients. The main areas of uncertainty with use of mesalamine in patients with UC center on the optimal dose for induction of response, how to maintain patient adherence and the role of mesalamine in cancer chemoprophylaxis. Generic forms of mesalamine have yet to be approved by regulatory bodies in the USA.

Absence of ABCG2-mediated mucosal detoxification in patients with active inflammatory bowel disease is due to impeded protein folding

Xenotoxic damage in inflammatory diseases, including IBD (inflammatory bowel disease), is compounded by reduced activity of the xenobiotic transporter ABCG2 (ATP-binding-cassette G2) during the inflammatory state. An association between the activation of the unfolded protein response pathway and inflammation prompted us to investigate the possibility that reduced ABCG2 activity is causally linked to this response. To this end, we correlated expression of ABCG2 and the unfolded protein response marker GRP78 (glucose-regulated protein of 78 kDa) in colon biopsies from healthy individuals (n=9) and patients with inactive (n=67) or active (n=55) IBD, ischaemic colitis (n=10) or infectious colitis (n=14). In addition, tissue specimens throughout the small bowel from healthy individuals (n=27) and from patients with inactive (n=9) or active (n=25) Crohn's disease were co-stained for ABCG2 and GRP78. In all biopsies from patients with active inflammation, irrespective of the underlying disease, an absolute negative correlation was observed between epithelial ABCG2 expression and GRP78 expression, suggesting that inflammation-dependent activation of the unfolded protein response is responsible for suppression of ABCG2 function. The link between the unfolded protein response and functional ABCG2 expression was further corroborated by live imaging of ABCG2-expressing cells, which showed that various inflammatory mediators, including nitric oxide, activate the unfolded protein response and concomitantly reduce plasma membrane localization as well as transport function of ABCG2. Thus a novel mechanism for explaining xenobiotic stress during inflammation emerges in which intestinal inflammation activates the unfolded protein response, in turn abrogating defences against xenobiotic challenge by impairing ABCG2 expression and function.

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.

Pathogenesis and biomarkers of carcinogenesis in ulcerative colitis

One of the most serious complications of ulcerative colitis is the development of colorectal cancer. Screening patients with ulcerative colitis by standard histological examination of random intestinal biopsy samples might be inefficient as a method of cancer surveillance. This Review focuses on the current understanding of the pathogenesis of ulcerative colitis-associated colorectal cancer and how this knowledge can be transferred into patient management to assist clinicians and pathologists in identifying patients with ulcerative colitis who have an increased risk of colorectal cancer. Inflammation-driven mechanisms of DNA damage, including the generation and effects of reactive oxygen species, microsatellite instability, telomere shortening and chromosomal instability, are reviewed, as are the molecular responses to genomic stress. We also discuss how these mechanisms can be translated into usable biomarkers. Although progress has been made in the understanding of inflammation-driven carcinogenesis, markers based on these findings possess insufficient sensitivity or specificity to be usable as reliable biomarkers for risk of colorectal cancer development in patients with ulcerative colitis. However, screening for mutations in p53 could be relevant in the surveillance of patients with ulcerative colitis. Several other new biomarkers, including senescence markers and α-methylacyl-CoA-racemase, might be future candidates for preneoplastic markers in ulcerative colitis.

Role of organic anion-transporting polypeptides for cellular mesalazine (5-aminosalicylic acid) uptake

The therapeutic effects and metabolism of mesalazine (5-aminosalicylic acid) in patients with inflammatory bowel disease require intracellular accumulation of the drug in intestinal epithelial cells and hepatocytes. The molecular mechanisms of mesalazine uptake into cells have not been characterized so far. Using human embryonic kidney cells stably expressing uptake transporters of the organic anion-transporting polypeptide (OATP) family, which are expressed in human intestine and/or liver, we found that mesalazine uptake is mediated by OATP1B1, OATP1B3, and OATP2B1 but not by OATP1A2 and OATP4A1. Moreover, genetic variations (*1b, *5, *15) in the SLCO1B1 gene encoding OATP1B1 reduced the K(m) value for mesalazine uptake from 55.1 to 16.3, 24.3, and 32.4 μM, respectively, and the respective V(max) values. Finally, budesonide, cyclosporine, and rifampin were identified as inhibitors of OATP1B1-, OATP1B3-, and OATP2B1-meditated mesalazine uptake. These in vitro data indicate that OATP-mediated uptake and its modification by genetic factors and comedications may play a role for mesalazine effects.