Sulindac for polyposis of the colon

Uptake of Aspirin Chemoprevention in Patients With Lynch Syndrome

PURPOSE

Individuals with Lynch syndrome (LS) are at a high lifetime risk of colorectal cancer (CRC) and other cancers. Aspirin (ASA), a nonsteroidal anti-inflammatory drug (NSAID), has proven chemopreventive benefits in LS, with the CAPP2 randomized double-blind placebo-controlled trial demonstrating a 60% relative risk reduction for CRC among participants who adhered to ASA for 2 years or more. This study sought to characterize uptake of ASA/NSAIDs among individuals with LS and to understand factors associated with use.

METHODS

Individuals with LS were invited (June 2020-August 2022) to complete a one-time electronic survey about LS screening behaviors, uptake of ASA/NSAIDs, and current/emerging cancer prevention options. Participants were recruited from the Fox Chase Cancer Center (FCCC) Risk Assessment Program Registry and through a research invitation posted to two patient-facing LS advocacy websites.

RESULTS

Two hundred and ninety-six participants completed the survey including 116 (39.2%) from FCCC and 180 (60.8%) recruited via the Internet, including 14.9% non-US based individuals. Uptake of regular ASA or NSAIDs was modest at 34.8% and was even lower (25.7%) when focusing on individuals taking ASA or NSAIDs solely for chemoprevention of LS. More than half (55%) were taking <100 mg ASA daily. In multivariable modeling, lower perceived threat of LS (odds ratio [OR], 0.84 [95% CI, 0.72 to 0.98]), lower concern for side effects (OR, 0.86 [95% CI, 0.76 to 0.99]), and higher likelihood of recommending ASA/NSAIDs to family or a friend were all associated with ASA/NSAIDs use (OR, 1.70 [95% CI, 1.37 to 2.10]).

CONCLUSION

Uptake of ASA/NSAIDs chemoprevention is modest among individuals with LS. Patient perceptions of the pros and cons of ASA, more so than demographic and disease-related factors, were associated with chemoprevention uptake.

Chemoprevention in hereditary digestive neoplasia: A comprehensive review

Hereditary syndromes, such as familial adenomatous polyposis (FAP), MUTYH polyposis or Lynch syndrome, are particularly predisposing to the development of colorectal cancer. These situations have necessitated the development of adapted prevention strategies based largely on reinforced endoscopic surveillance and the search for complementary prevention strategies. This is the case for chemoprevention, which is the long-term administration of chemical agents limiting carcinogenesis, used as primary or secondary prophylaxis. The aim of this review is to present the available literature and the latest advances in chemoprevention in patients with FAP or MUTYH and other polyposis as well as in patients with Lynch syndrome. The main conclusions of the few available guidelines in these situations are also discussed.

The effect of sulindac on redox homeostasis and apoptosis-related proteins in melanotic and amelanotic cells

BACKGROUND

Non-steroidal anti-inflammatory drugs have been shown to inhibit the development of induced neoplasms. Our previous research demonstrated that the cytotoxicity of sulindac against melanoma cells is comparable to dacarbazine, the drug used in chemotherapy. The aim of this study was to investigate the mechanism of sulindac cytotoxicity on COLO 829 and C32 cell lines.

METHODS

The influence of sundilac on the activity of selected enzymes of the antioxidant system (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)) and the content of hydrogen peroxide as well as the level of proteins initiating (p53, Bax) and inhibiting (Bcl-2) apoptosis were measured in melanoma cells.

RESULTS

In melanotic melanoma cells, sulindac increased the activity of SOD and the content of H2O2 but decreased the activity of CAT and GPx. The level of p53 and Bax proteins rose but the content of Bcl-2 protein was lowered. Similar results were observed for dacarbazine. In amelanotic melanoma cells, sulindac did not cause an increase in the activity of measured enzymes or any significant changes in the level of apoptotic proteins.

CONCLUSION

The cytotoxic effect of sulindac in the COLO 829 cell line is connected to disturbed redox homeostasis by changing the activity of SOD, CAT, GPx, and level of H2O2. Sulindac also induces apoptosis by changing the ratio of the pro-apoptotic/anti-apoptotic protein. The presented studies indicate the possibility of developing target therapy against melanotic melanoma using sulindac.

Long-term chemoprevention in patients with adenomatous polyposis coli: an observational study

Prospective short-term studies on effectiveness of non-steroidal anti-inflammatory drugs (NSAIDs) point towards a decrease in the number and size of polyps. Effectiveness and safety in the prevention of progression in familial polyposis with NSAIDs in long-term use, which is the prerequisite for therapeutic evaluation in prospective studies, is unknown. The total absolute observation period of 54 patients under sulindac was 399 patient years with a mean of 7.4 (2-19) years per patient. 36 patients (66.7%) showed a fast decrease of polyp burden, 8 (14.8%) were slow responders, and 9 (16.7%) had stable disease; one patient had a slow progression. Upper gastrointestinal (GI) polyp burden remained stable in 47% patients, increased in 31%, and improved in 22%. Advanced adenomas were found in 8 patients only within the first 5 years of chemoprevention, no patient developed desmoid disease, anamnestically evaluated on every follow-up. There were no life-threatening side-effects. Dosage and delivery pattern were essential for effectiveness. This study provides evidence that chemoprevention with sulindac is effective and safe and can, either alone or in combination with other drugs, become a long-term management option in cases of adenomatous polyposis. These results justify further long-term prospective chemoprevention studies to elaborate treatment protocols and guidelines.

Limited Proteolysis of Cyclooxygenase-2 Enhances Cell Proliferation

Accumulating evidence suggests that the cyclooxygenase-2 (COX-2) enzyme has additional catalytic-independent functions. Here we show that COX-2 appears to be cleaved in mouse and human tumors, which led us to hypothesize that COX-2 proteolysis may play a role in cell proliferation. The data presented herein show that a K598R point mutation at the carboxyl-terminus of COX-2 causes the appearance of several COX-2 immunoreactive fragments in nuclear compartments, and significantly enhances cell proliferation. In contrast, insertion of additional mutations at the border of the membrane-binding and catalytic domains of K598R COX-2 blocks fragment formation and prevents the increase in proliferation. Transcriptomic analyses show that K598R COX-2 significantly affects the expression of genes involved in RNA metabolism, and subsequent proteomics suggest that it is associated with proteins that regulate mRNA processing. We observe a similar increase in proliferation by expressing just that catalytic domain of COX-2 (ΔNT- COX-2), which is completely devoid of catalytic activity in the absence of its other domains. Moreover, we show that the ΔNT- COX-2 protein also interacts in the nucleus with β-catenin, a central regulator of gene transcription. Together these data suggest that the cleavage products of COX-2 can affect cell proliferation by mechanisms that are independent of prostaglandin synthesis.

Fusobacterium nucleatum-positive colorectal cancer

Colorectal cancer (CRC) is an important threat to human health and the fourth leading cause of mortality worldwide. Accumulating evidence indicates that the composition of the intestinal flora is associated with the occurrence of CRC. Fusobacterium nucleatum (Fn), one of the highly enriched bacteria in CRC tissues, invades the mucosa with adhesion factors and virulence proteins, interacts with the host immune system and promotes the occurrence and development of CRC and chemoresistance. Fn infection is prevalent in human colorectal carcinoma, although the infection rate varies in different regions. Fn may be used as a prognostic indicator of CRC. It is important to understand the multi-pathway carcinogenic mechanisms associated with CRC in order to develop novel antibacterial drugs against Fn. The current review summarizes the role of Fn and relevant research concerning CRC published in recent years, focusing on Fn infection in CRC, pathogenesis of Fn, Fn-positive CRC treatment, screening and prevention strategies against Fn-positive CRC.

Role of epigenetics in transformation of inflammation into colorectal cancer

Molecular mechanisms associated with inflammation-promoted tumorigenesis have become an important topic in cancer research. Various abnormal epigenetic changes, including DNA methylation, histone modification, chromatin remodeling, and noncoding RNA regulation, occur during the transformation of chronic inflammation into colorectal cancer (CRC). These changes not only accelerate transformation but also lead to cancer progression and metastasis by activating carcinogenic signaling pathways. The NF-κB and STAT3 signaling pathways play a particularly important role in the transformation of inflammation into CRC, and both are critical to cellular signal transduction and constantly activated in cancer by various abnormal changes including epigenetics. The NF-κB and STAT3 signals contribute to the microenvironment for tumorigenesis through secretion of a large number of pro-inflammatory cytokines and their crosstalk in the nucleus makes it even more difficult to treat CRC. Compared with gene mutation that is irreversible, epigenetic inheritance is reversible or can be altered by the intervention. Therefore, understanding the role of epigenetic inheritance in the inflammation-cancer transformation may elucidate the pathogenesis of CRC and promote the development of innovative drugs targeting transformation to prevent and treat this malignancy. This review summarizes the literature on the roles of epigenetic mechanisms in the occurrence and development of inflammation-induced CRC. Exploring the role of epigenetics in the transformation of inflammation into CRC may help stimulate futures studies on the role of molecular therapy in CRC.

Molecular Markers for Colorectal Cancer

Colorectal cancers develop through at least 3 major pathways, including chromosomal instability, mismatch repair, and methylator phenotype. These pathways can coexist in a single individual and occur in both sporadic and inherited colorectal cancers. In spite of the unique molecular and genetic signatures of colorectal cancers, nonspecific chemotherapy based on the antineoplastic effects of 5-fluorouracil is the cornerstone of therapy for stage III and some stage II disease. Techniques to recognize colorectal cancer at the molecular level have facilitated development of new signature drugs designed to inhibit the unique pathways of colorectal cancer growth and immunity.

Cancer Cell-Autonomous Parainflammation Mimics Immune Cell Infiltration

Parainflammation is a unique variant of inflammation, characterized by epithelial-autonomous activation of inflammatory response. Parainflammation has been shown to strongly promote mouse gut tumorigenesis upon p53 loss. In a recent study, we explored the prevalence of parainflammation in human cancer and determined its relationship to certain molecular and clinical parameters affecting treatment and prognosis. Parainflammation can be identified from a 40-gene signature and is found in both carcinoma cell lines and a variety of primary tumors, independently of tumor microenvironment. Here, we discuss the implications of our findings in analyses of tumor microenvironment, suggesting that as tumor cell gene expression may often mimic immune and inflammatory infiltration, caution should be applied when interpreting tumor expression data. We also address the connection between parainflammation and prevalence of p53 mutations in specific types of tumors, and cancer prevention by regular usage of NSAIDs. We suggest that parainflammation may serve as a novel biomarker for screening patients who may particularly benefit from NSAID treatment. Cancer Res; 77(14); 3740-4. ©2017 AACR.

The protein kinase promiscuities in the cancer-preventive mechanisms of NSAIDs

NSAIDs have been observed to have cancer-preventive properties, but the actual mechanism is elusive. We hypothesize that NSAIDs might have an effect through common pathways and targets of anticancer drugs by exploiting promiscuities of anticancer drug targets. Here, we have explored NSAIDs by their structural and pharmacophoric similarities with small anticancer molecules. In-silico analyses have shown a strong similarity between NSAIDs and protein kinase (PK) inhibitors. The calculated affinities of NSAIDs were found to be lower than the affinities of anticancer drugs, but higher than the affinities of compounds that are not specific to PKs. The competitive inhibition model suggests that PK might be inhibited by around 10%, which was confirmed by biochemical screening of some NSAIDs against PKs. NSAIDs did not affect all PKs universally, but had specificities for certain sets of PKs, which differed according to the NSAID. The study revealed potentially new features and mechanisms of NSAIDs that are useful in explaining their role in cancer prevention, which might lead to clinically significant breakthroughs in the future.

Inflammatory networks underlying colorectal cancer

Inflammation is emerging as one of the hallmarks of cancer, yet its role in most tumors remains unclear. Whereas a minority of solid tumors are associated with overt inflammation, long-term treatment with non-steroidal anti-inflammatory drugs is remarkably effective in reducing cancer rate and death. This indicates that inflammation might have many as-yet-unrecognized facets, among which an indolent course might be far more prevalent than previously appreciated. In this Review, we explore the various inflammatory processes underlying the development and progression of colorectal cancer and discuss anti-inflammatory means for its prevention and treatment.

Use of NSAIDs for the Chemoprevention of Colorectal Cancer

OBJECTIVE:

To discuss the role of nonsteroidal antiinflammatory drugs (NSAIDs) in the chemoprevention of colorectal cancer.

DATA SOURCES:

A MEDLINE search (1966–May 2003) was performed to identify key literature. Search items included, but were not limited to, NSAIDs, colorectal cancer, chemoprevention, cyclooxygenase-2 (COX-2)–specific inhibitors, and familial adenomatous polyposis (FAP).

STUDY SELECTION AND DATA EXTRACTION:

The search included experimental (in vitro and animal models) and clinical studies evaluating the use of NSAIDs for the chemoprevention of colorectal cancer. The MEDLINE search was supplemented by references from selected articles.

DATA SYNTHESIS:

Numerous experimental, epidemiologic, and clinical studies suggest that NSAIDs have promise as anticancer agents. The mechanism by which NSAIDs lead to decreased colon carcinogenesis is not fully understood, but may involve restoration of apoptosis and inhibition of prostaglandin-mediated angiogenesis. Compelling evidence from many observational studies has consistently documented a 40–50% reduction in the risk of adenomatous polyps, colorectal cancer incidence, and mortality in patients using NSAIDs. Recent randomized, controlled trials have demonstrated a benefit with aspirin in reducing the rate of development of new or recurrent adenomas in high-risk patients. In addition, randomized studies using sulindac and celecoxib in patients with FAP have documented significant regression of existing adenomatous polyps.

CONCLUSIONS:

Inhibition of COX-2 is an example of a targeted approach to the chemoprevention of colorectal cancer. However, controversy exists about the safety, efficacy, and optimal treatment regimen of NSAIDs as long-term chemopreventive agents in the general population. Ongoing studies in high-risk patients with both selective and nonselective COX inhibitors will provide important information in the area of colorectal chemoprevention, but clinical trials' use of adenomas as surrogate markers for chemoprevention trials makes their application to the general population limited.

In vitro antiproliferative activity of 2,3-dihydroxy-9,10-anthraquinone induced apoptosis against COLO320 cells through cytochrome c release caspase mediated pathway with PI3K/AKT and COX-2 inhibition

The present study investigated the anticancer activity of 2,3-dihydroxy-9,10-anthraquinone against different cancer cells such as MCF-7, COLO320, HepG-2, Skov-3, MOLM-14, NB-4, CEM, K562, Jurkat, HL-60, U937, IM-9 and Vero. 2,3-dihydroxy-9,10-anthraquinone showed good antiproliferative activity against COLO320 cells when compared to other tested cells. The cytotoxicity results showed 79.8% activity at the dose of 2.07 μM with IC50 value of 0.13 μM at 24 h in COLO320 cells. So we chose COLO320 cells for further anticancer studies. mRNA expression was confirmed by qPCR analysis using SYBR green method. Treatment with 2,3-dihydroxy-9,10-anthraquinone was found to trigger intrinsic apoptotic pathway as indicated by down regulation of Bcl-2, Bcl-xl; up regulation of Bim, Bax, Bad; release of cytochrome c and pro-caspases cleaving to caspases. Furthermore, 2,3-dihydroxy-9,10-anthraquinone stopped at G0/G1 phase with modulation in protein levels of cyclins. On the other hand PI3K/AKT signaling plays an important role in cell metabolism. We found that 2,3-dihydroxy-9,10-anthraquinone inhibits PI3K/AKT activity after treatment. Also, COX-2 enzyme plays a major role in colorectal cancer. Our results showed that the treatment significantly reduced COX-2 enzyme in COLO320 cells. These results indicated antiproliferative activity of 2,3-dihydroxy-9,10-anthraquinone involving apoptotic pathways, mitochondrial functions, cell cycle checkpoint and controlling the over expression genes during the colorectal cancer. Molecular docking studies showed that the compound bound stably to the active sites of Bcl-2, COX-2, PI3K and AKT. This is the first report of anticancer mechanism involving 2,3-dihydroxy-9,10-anthraquinone in COLO320 cells. The present results might provide helpful suggestions for the design of antitumor drugs toward colorectal cancer treatment.

Regression of Colonic Adenomas After Treatment With Sulindac in Familial Adenomatous Polyposis: A Case With a 2-Year Follow-up Without a Prophylactic Colectomy

Familial adenomatous polyposis (FAP) is an autosomal dominant disorder characterized by hundreds of colorectal adenomatous polyps that progress to colorectal cancer. Management of patients with FAP is with a total colectomy. Chemopreventive strategies have been studied in FAP patients in an effort to delay the development of adenomas in the upper and the lower gastrointestinal tract and to prevent recurrence of adenomas in the retained rectum of patients after prophylactic surgery. Sulindac, a nonsteroidal anti-inflammatory drug, causes regression of colorectal adenomas in the retained rectal segment of FAP patients. However, evidence regarding long-term use of this therapy and its effect on the intact colon has been insufficient. We report a case in which the long-term use of sulindac was effective in reducing the size and the number of colonic polyps in patients with FAP without a prophylactic colectomy and polypectomy; we also present a review of the literature.

The discovery and development of cyclooxygenase-2 inhibitors as potential anticancer therapies

INTRODUCTION

In the past, clinical studies had demonstrated that aspirin and NSAIDs reduce the risk of colorectal cancer. After the discovery of selective prostaglandin-endoperoxide synthase 2 (PTGS2) inhibitors, the further beneficial effects of celecoxib and some other related structures (coxibs) have been demonstrated in both in vivo and in vitro studies.

AREAS COVERED

The authors illustrate the role of prostaglandins following the overexpression of PTGS2 (COX-2) in signaling pathways. The authors elucidate the role of coxibs in cell proliferation, apoptosis, angiogenesis and multi-drug resistance and discuss the molecular mechanisms involved. The authors also present the strong evidence related to the usefulness of coxibs in several cancer cell lines.

EXPERT OPINION

There have been a number of PTGS2 (COX-2) selective inhibitors suggested as potential anticancer therapies. In recent years, the development of nanotechnology has also had an impact on chemotherapy. Indeed, nanoparticles of cytotoxic drug carriers have demonstrated potential through their accumulation in cancer cells, and targeting these nanoparticles has been under evaluation. This area could be opened up for coxib development as they are potentially important targets in cancer cells. Further research using celecoxib as a co-drug with PTGS2-overexpressed and PTGS2-independent cancer is still needed.

The role of inflammation in colon cancer

Colorectal cancer (CRC) is the one of the leading causes of cancer-related deaths in the world. CRC is responsible for more than 600,000 deaths annually and incidence rates are increasing in most of the developing countries. Epidemiological and laboratory investigations suggest that environmental factors such as western style dietary habits, tobacco-smoking, and lack of physical activities are considered as risks for CRC. Molecular pathobiology of CRC implicates pro-inflammatory conditions to promote the tumor malignant progression, invasion, and metastasis. It is well known that patients with inflammatory bowel disease are at higher risk of CRC. Many evidences exist reiterating the link between Inflammation and CRC. Inflammation involves interaction between various immune cells, inflammatory cells, chemokines, cytokines, and pro-inflammatory mediators, such as cyclooxygenase (COX) and lipoxygenase (LOX) pathways, which may lead to signaling towards, tumor cell proliferation, growth, and invasion. Thus, this review will focus on mechanisms by which pro-inflammatory mediators and reactive oxygen/nitrogen species play a role in promoting CRC. Based on these mechanisms, various preventive strategies, involving anti-inflammatory agents, such as COX inhibitors, COX-LOX inhibitors, iNOS inhibitors, natural supplements/agents, and synthetic agents, that blocks the inflammatory pathways and suppress CRC are discussed in this review.

Nonsteroidal anti-inflammatory drug sulindac sulfide suppresses structural protein Nesprin-2 expression in colorectal cancer cells

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) are well known for treating inflammatory disease and have been reported to have anti-tumorigenic effects. Their mechanisms are not fully understood, but both cyclooxygenase (COX) dependent and independent pathways are involved. Our goal was to shed further light on COX-independent activity.

METHODS

Human colorectal cancer cells were observed under differential interference contrast microscopy (DICM), fluorescent microscopy, and micro-impedance measurement. Microarray analysis was performed using HCT-116 cells treated with sulindac sulfide (SS). PCR and Western blots were performed to confirm the microarray data and immunohistochemistry was performed to screen for Nesprin-2 expression. Micro-impedance was repeating including Nesprin-2 knock-down by siRNA.

RESULTS

HCT-116 cells treated with SS showed dramatic morphological changes under DICM and fluorescent microscopy, as well as weakened cellular adhesion as measured by micro-impedance. Nesprin-2 was selected from two independent microarrays, based on its novelty in relation to cancer and its role in cell organization. SS diminished Nesprin-2 mRNA expression as assessed by reverse transcriptase and real time PCR. Various other NSAIDs were also tested and demonstrated that inhibition of Nesprin-2 mRNA was not unique to SS. Additionally, immunohistochemistry showed higher levels of Nesprin-2 in many tumors in comparison with normal tissues. Further micro-impedance experiments on cells with reduced Nesprin-2 expression showed a proportional loss of cellular adhesion.

CONCLUSIONS

Nesprin-2 is down-regulated by NSAIDs and highly expressed in many cancers.

GENERAL SIGNIFICANCE

Our data suggest that Nesprin-2 may be a potential novel oncogene in human cancer cells and NSAIDs could decrease its expression.

COX-Independent Mechanisms of Cancer Chemoprevention by Anti-Inflammatory Drugs

Epidemiological and clinical studies suggest that non-steroidal anti-inflammatory drugs (NSAIDs), including cyclooxygenase (COX)-2 selective inhibitors, reduce the risk of developing cancer. Experimental studies in human cancer cell lines and rodent models of carcinogenesis support these observations by providing strong evidence for the antineoplastic properties of NSAIDs. The involvement of COX-2 in tumorigenesis and its overexpression in various cancer tissues suggest that inhibition of COX-2 is responsible for the chemopreventive efficacy of these agents. However, the precise mechanisms by which NSAIDs exert their antiproliferative effects are still a matter of debate. Numerous other studies have shown that NSAIDs can act through COX-independent mechanisms. This review provides a detailed description of the major COX-independent molecular targets of NSAIDs and discusses how these targets may be involved in their anticancer effects. Toxicities resulting from COX inhibition and the suppression of prostaglandin synthesis preclude the long-term use of NSAIDs for cancer chemoprevention. Furthermore, chemopreventive efficacy is incomplete and treatment often leads to the development of resistance. Identification of alternative NSAID targets and elucidation of the biochemical processes by which they inhibit tumor growth could lead to the development of safer and more efficacious drugs for cancer chemoprevention.

11β-Hydroxysteroid Dehydrogenase Type II is a Potential Target for Prevention of Colorectal Tumorigenesis

Colorectal cancer (CRC) is a leading cause of cancer death, yet primary prevention remains the best approach to reducing overall morbidity and mortality. There is a clear molecular link between cyclooxygenase-2 (COX-2)-derived prostaglandin E₂ (PGE₂) production and CRC progression. Although selective COX-2 inhibitors as well as non-steroidal anti-inflammatory drugs (NSAIDs) reduce the number and sizes of colonic adenomas, increased cardiovascular risks of selective COX-2 inhibitors and increased gastrointestinal side-effects of NSAIDs limit their use in chemoprevention of CRC. Glucocorticoids induce apoptosis and are endogenous, potent COX-2 inhibitors. Glucocorticoids have been used for the treatment of hematologic malignancies, but not for solid tumors due to adverse side-effects such as immunosuppression and osteoporosis. In tissues, glucocorticoid actions are down-regulated by t y p e 2 1 1 β-hydroxysteroid dehydrogenase (11βHSD2), and inhibition of 11βHSD2 activity will elevate intracellular active glucocorticoid to levels that effectively suppress COX-2 expression. Both COX-2 and 11βHSD2 increase in Apc^+/min mouse intestinal adenomas and human colonic adenomas and either pharmacologic or genetic 11βHSD2 inhibition leads to decreases in COX-2-mediated PGE₂ production in tumors and prevents adenoma formation, tumor growth, and metastasis. 11βHSD2 inhibition may represent a novel approach for CRC chemoprevention by increasing tumor cell intracellular glucocorticoid activity, which in turn inhibits tumor growth by suppressing the COX-2-derived PGE₂ pathway, as well as other pathways, without potential side-effects relating to chronic application of COX-2 inhibitors, NSAIDs and glucocorticoids.

Efficacy of dimethylaminoparthenolide and sulindac in combination with gemcitabine in a genetically engineered mouse model of pancreatic cancer

OBJECTIVES

Pancreatic cancer remains one of the deadliest diseases, with limited surgical and treatment options. Two targets of interest include the transcription factor nuclear factor-κB and cyclooxygenase-2, which are constitutively activated and overexpressed, respectively, in human pancreatic adenocarcinoma. We have previously shown that dimethylaminoparthenolide (DMAPT), a bioavailable nuclear factor-κB inhibitor, and the cyclooxygenase inhibitors sulindac and celecoxib have potential chemotherapeutic efficacy. The current study evaluates the efficacy of intervention with DMAPT and sulindac in the LSL-Kras(G12D);Pdx-1-Cre genetically engineered mouse model. Gemcitabine, traditionally a chemotherapeutic agent, has relatively low toxicity; thus, combinations with low-dose gemcitabine were also explored.

METHODS

LSL-Kras(G12D);Pdx-1-Cre mice at 7 months of age were randomized into placebo, DMAPT (40 mg/kg per day), sulindac (20 mg/kg per day), gemcitabine (50 mg/kg twice weekly), and combination treatment groups. After 3 months of treatment, the mice were killed.

RESULTS

The percentage of normal pancreatic ducts was significantly increased by the combinations of DMAPT/sulindac, DMAPT/gemcitabine, sulindac/gemcitabine, and DMAPT/sulindac/gemcitabine compared to placebo. Additionally, the percentage of mouse pancreatic intraepithelial neoplasia-2 lesions was significantly decreased by DMAPT/gemcitabine.

CONCLUSIONS

Intervention with DMAPT and sulindac in combination with gemcitabine may delay or prevent progression of premalignant pancreatic lesions in the LSL-Kras(G12D);Pdx-1-Cre mouse model of pancreatic cancer.

Multifaceted roles of PGE2 in inflammation and cancer

Prostaglandin E(2) (PGE(2)) is a bioactive lipid that elicits a wide range of biological effects associated with inflammation and cancer. PGE(2) exerts diverse effects on cell proliferation, apoptosis, angiogenesis, inflammation, and immune surveillance. This review concentrates primarily on gastrointestinal cancers, where the actions of PGE(2) are most prominent, most likely due to the constant exposure to dietary and environmental insults and the intrinsic role of PGE(2) in tissue homeostasis. A discussion of recent efforts to elucidate the complex and interconnected pathways that link PGE(2) signaling with inflammation and cancer is provided, supported by the abundant literature showing a protective effect of NSAIDs and the therapeutic efficacy of targeting mPGES-1 or EP receptors for cancer prevention. However, suppressing PGE(2) formation as a means of providing chemoprotection against all cancers may not ultimately be tenable, undoubtedly the situation for patients with inflammatory bowel disease. Future studies to fully understand the complex role of PGE(2) in both inflammation and cancer will be required to develop novel strategies for cancer prevention that are both effective and safe.

In silico predicative studies for cytotoxic potential of NSAIDs using self-organizing molecular field analysis

Antiproliferative potential of nonsteroidal anti-inflammatory drugs (NSAIDs) has generated an immense interest among the scientific fraternity to assess its broader role in the chemoprevention of colon cancer. Due to serious adverse events associated with the chemotherapy, NSAIDs have been exploited as adjuvants to synergize the cytotoxic potential of conventional chemotherapeutic agents at low-dose regimens. The present investigation has been focused on in silico model generation for in vitro cytotoxicity activity of the clinically active NSAIDs using self-organizing molecular field analysis (SOMFA) studies. A statistically validated robust model for a diverse group of NSAIDs having flexibility in structure and cytotoxicity activity was obtained using SOMFA. The statistical measures having good cross-validated correlation coefficient r (2) (cv) (.8291), noncross-validated correlation coefficient r (2) values (.8686), and high F test value (41.8722) proved significance in the generated model. Analysis of 3-dimensional quantitative structure activity relationship (3D-QSAR) models through electrostatic and shape grids provided additional valuable information regarding shape and electrostatic potential influence on in vitro cytotoxicity profile. The analysis of SOMFA results provided a better insight about the generation of molecular architecture of novel NSAIDs yet to be synthesized, with optimum in vitro cytotoxicity activity and improved therapeutic profile.

Colorectal cancer chemoprevention: is this the future of colorectal cancer prevention?

Colorectal cancer (CRC) is presently one of the most common causes of cancer-related death in our setting and affects a great number of people each year. Screening strategies are commonly used but they do not seem enough to avoid CRC development or prevent completely its mortality. Because of this fact other prevention strategies have gained interest in recent years. Chemoprevention seems to be an attractive option in this setting and several drugs have been studied in this field. This review is focused on salicylates, nonsteroidal anti-inflammatory drugs (NSAIDs) and cycloxygenase-2 inhibitors (COXIBs), whose mechanism of action could be directly related to colon cancer chemoprevention.

Cyclooxygenase- and lipoxygenase-mediated DNA damage

Cancer is a disease of aging, and so with the increasing age of the US population, the incidence of cancer is also increasing. Furthermore the global burden of cancer continues to increase largely because of aging and growth of the world population together with increasing smoking rates in economically developing countries. Tumor formation is critically dependent upon two processes--initiation and progression. The initiation step is mediated by DNA damage, which causes activating mutations in proto-oncogenes and inactivation of tumor suppressor genes in many cancers. This is then thought to facilitate tumor progression and metastasis. Cyclooxygenase-2 (COX-2) is upregulated at an early stage in tumorigenesis and has been implicated as an important mediator of proliferation through the increased formation of bioactive arachidonic acid (AA) metabolites such as prostaglandin E(2). Significantly, we have found that COX-2-mediated AA metabolism also results in the formation of heptanone-etheno (Hε)-DNA adducts. Furthermore, we showed that the Hε-DNA adducts arose from the reaction of DNA with the lipid hydroperoxide-derived bifunctional electrophile, 4-oxo-2(E)-nonenal (ONE). Similarly, 5-lipoxoygenase-mediated AA metabolism also results in the formation of ONE-derived DNA adducts. The resulting Hε-DNA adducts are highly mutagenic in mammalian cell lines suggesting that these pathways could be (in part) responsible for the somatic mutations observed in tumorigenesis. As approximately 80% of cancers arise from somatic mutations, this provides an additional link between the upregulation of COX-2 and tumorigenesis.

Chemoprevention in familial adenomatous polyposis

Familial adenomatous polyposis (FAP) predictably leads to adenomas and eventual adenocarcinomas in the lower gastrointestinal tract and less frequently, the upper gastrointestinal tract. Chemopreventive strategies have been studied in FAP patients to delay the development of adenomas in the upper and lower gastrointestinal tract, as well as to prevent recurrence of adenomas in the retained rectum of patients after prophylactic surgery with colectomy and ileorectal anastamosis (IRA). The nonsteroidal anti-inflammatory drug (NSAID) sulindac and selective cyclooxygenase-2 (COX-2) inhibitor celecoxib reduce polyposis of the retained rectum after colectomy with IRA. Reports of cardiovascular risks of some NSAIDs and selective COX-2 inhibitors have led to promising studies of lower doses in combination with ursodeoxycholic acid, statin, and difluoromethylornithine. Curcumin and eicosapentaenoic acid show efficacy in small clinical trials of FAP chemoprevention. This article will review the concept of chemoprevention and the current clinical literature in FAP chemoprevention.

Regulation of endothelial cell functions by basement membrane- and arachidonic acid-derived products

Angiogenesis, the formation of new blood vessels from preexisting vasculature, is required for normal physiological as well as pathological events. The angiogenic process requires endothelial cells to proliferate, migrate, and undergo tubulogenesis. These multistep processes necessitate secretion of pro-angiogenic growth factors, activation of specific intracellular signaling, and interaction of endothelial cells with basement membrane (BM) extracellular matrix components. The generation and release of angiogenic molecules are highly regulated and are influenced by numerous factors, including BM-derived fragments, proteolytic enzymes, as well as metabolites of arachidonic acid (AA). The interactions between these key modulators of angiogenesis is extremely complex, as AA metabolites can regulate the synthesis of soluble angiogenic factors, BM components, as well as enzymes capable of cleaving BM components, which result in the generation of pro- and/or anti-angiogenic products. Furthermore, some BM-derived fragments can alter the expression of AA-converting enzymes and consequently the synthesis of angiogenic factors. In this review we describe the relationship between BM components and AA metabolites with respect to the regulation of endothelial cell functions in health and disease.

Cyclo-oxygenase-2 expression in photon-radiated and non-radiated uveal melanomas

PURPOSE

To determine and compare cyclo-oxygenase-2 (COX-2) expression in photon-radiated and non-radiated malignant uveal melanomas and to analyse the correlation between COX-2 expression and prognosis.

METHODS

Immunohistochemical staining for COX-2 was performed on 21 uveal melanomas that were endoresected after prior stereotactic radiotherapy with photons and on 22 tumours that were treated by endoresection without prior radiotherapy. COX-2 staining was further analysed in respect to cell type, maximal prominence, time interval between radiotherapy and surgery, apoptotic index (AI), proliferative index (PI) and the development of metastatic disease.

RESULTS

There was no difference in COX-2 expression between radiated and non-radiated melanomas (P>0.15). COX-2 staining correlated with neither the tumour prominence (P>0.40) nor the AI or the PI (both P>0.35). Tumours with high COX-2 expression were significantly more likely to develop metastasis (P=0.022).

CONCLUSION

Radiotherapy with photons does not induce COX-2 expression in malignant melanomas of the uvea. But high COX-2 expression may be a marker for poor prognosis.

Primary prevention of colorectal cancer

Colorectal cancer has been strongly associated with a Western lifestyle. In the past several decades, much has been learned about the dietary, lifestyle, and medication risk factors for this malignancy. Although there is controversy about the role of specific nutritional factors, consideration of dietary pattern as a whole appears useful for formulating recommendations. For example, several studies have shown that high intake of red and processed meats, highly refined grains and starches, and sugars is related to increased risk of colorectal cancer. Replacing these factors with poultry, fish, and plant sources as the primary source of protein; unsaturated fats as the primary source of fat; and unrefined grains, legumes and fruits as the primary source of carbohydrates is likely to lower risk of colorectal cancer. Although a role for supplements, including vitamin D, folate, and vitamin B6, remains uncertain, calcium supplementation is likely to be at least modestly beneficial. With respect to lifestyle, compelling evidence indicates that avoidance of smoking and heavy alcohol use, prevention of weight gain, and maintenance of a reasonable level of physical activity are associated with markedly lower risks of colorectal cancer. Medications such as aspirin and nonsteroidal anti-inflammatory drugs and postmenopausal hormones for women are associated with substantial reductions in colorectal cancer risk, though their utility is affected by associated risks. Taken together, modifications in diet and lifestyle should substantially reduce the risk of colorectal cancer and could complement screening in reducing colorectal cancer incidence.

Inherited cancer syndromes in children and young adults

Geneticists estimate that 5% to 10% of all cancers diagnosed in the pediatric age range occur in children born with a genetic mutation that directly increases their lifetime risk for neoplasia. However, despite the fact that only a fraction of cancers in children occur as a result of an identified inherited predisposition, characterizing genetic mutations responsible for increased cancer risk in such syndromes has resulted in a profound understanding of relevant molecular pathways involved in carcinogenesis and/or resistance to neoplasia. Importantly, because most cancer predisposition syndromes result in an increased risk of a small number of defined malignancies, personalized prophylactic surveillance and preventive measures can be implemented in affected patients. Lastly, many of the same genetic targets identified from cancer-prone families are mechanistically involved in the majority of sporadic cancers in adults and children, thereby underscoring the clinical relevance of knowledge gained from these defined syndromes and introducing novel therapeutic opportunities to the broader oncologic community. This review highlights the clinical and genetic features of many of the known constitutional genetic syndromes that predispose to malignancy in children and young adults.

Chronic cyclooxygenase-2 inhibition promotes myofibroblast-associated intestinal fibrosis

Anti-inflammatory drugs prevent intestinal tumor formation, an activity related to their ability to inhibit inflammatory pathway signaling in the target tissue. We previously showed that treatment of Min/(+) mice with the selective cyclooxygenase-2 (COX-2) inhibitor celecoxib induced rapid tumor regression; however, drug-resistant tumors appeared with long-term treatment. In this study, we investigated whole-tissue changes in inflammatory signaling by studying constituents of the tissue stroma and extracellular matrix. We found that celecoxib resistance was associated with changes in factors regulating autocrine transforming growth factor-beta (TGFbeta) signaling. Chronic drug treatment expanded the population of bone marrow-derived CD34(+) vimentin(+) alphaSMA(-) myofibroblast precursors and alphaSMA(+) vimentin(+) F4/80(-) myofibroblasts in the lamina propria and submucosa, providing a source of increased TGFbeta and COX-2 expression. Membrane constituents regulating TGFbeta availability, including syndecan-1 and heparanase-1, were also modified by chronic treatment in a manner promoting increased TGFbeta signaling. Finally, long-term celecoxib treatment induced tissue fibrosis, as indicated by increased expression of collagen, fibronectin, and laminin in the basement membrane. We conclude that chronic COX-2 inhibition alters TGFbeta signaling in the intestinal mucosa, producing conditions consistent with chronic inflammation.

Cellular and molecular pathways linking inflammation and cancer

Several experimental and epidemiological evidence indicate that, irrespective of the trigger for the development (chronic infection/inflammation or genetic alteration), a "smouldering" inflammation is associated with the most of, if not all, tumours and supports their progression. Several evidence have highlighted that tumours promote a constant influx of myelomonocytic cells that express inflammatory mediators supporting pro-tumoral functions. Myelomonocytic cells are key orchestrators of cancer-related inflammation associated with proliferation and survival of malignant cells, subversion of adaptive immune response, angiogenesis, stroma remodelling and metastasis formation. Although the connection between inflammation and cancer is unequivocal the mechanistic basis of such association are largely unknown. Recent advances in the understanding of the cellular and molecular pathways involved in cancer-related inflammation as well as their potential relevance as diagnostic, prognostic and therapeutic targets are herein discussed.

Five-year efficacy and safety analysis of the Adenoma Prevention with Celecoxib Trial

The Adenoma Prevention with Celecoxib Trial examined the efficacy and safety of the cyclooxygenase (Cox)-2 inhibitor, celecoxib, for sporadic colorectal adenoma prevention in patients at high risk for colorectal cancer. The trial randomized 2,035 subjects to receive either placebo, celecoxib 200 mg twice daily, or celecoxib 400 mg twice daily. The primary study safety and efficacy analyses involved 3 years of treatment. The results showed significant antitumor effect but also indicated increased cardiovascular adverse events in patients treated with celecoxib compared with placebo. A total of 933 patients participated in an extension of the Adenoma Prevention with Celecoxib Trial, with a planned total treatment and surveillance duration of 5 years. Study medication was stopped early, resulting in a median treatment duration of 3.1 years for those with a year 5 colonoscopy. Patients treated on the placebo arm had a cumulative adenoma incidence of 68.4% over 5 years of observation. This figure was 59.0% (P < 0.0001) for those receiving low-dose celecoxib, and 60.1% (P < 0.0001) for those receiving high-dose celecoxib. The cumulative incidence of advanced adenomas over 5 years was 21.3% of those taking placebo, 12.5% (P < 0.0001) of those taking low dose celecoxib and 15.8% (P < 0.0001) of those taking high-dose celecoxib. Investigator reported treatment emergent adverse events were similar across all treatment groups for categories including renal and hypertensive events and gastrointestinal ulceration and hemorrhage events. For a category composed of cardiovascular and thrombotic events, the risk relative to placebo was 1.6 (95% confidence interval, 1.0, 2.5) for those using 200 mg twice daily celecoxib and 1.9 (95% confidence interval, 1.2, 3.1) for those using 400 mg twice daily celecoxib. Secondary analysis showed an interaction between a baseline history of atherosclerotic heart disease and study drug use with respect to cardiovascular and thrombotic adverse events (P = 0.004). These results confirm the inhibitory effect of celecoxib on colorectal adenoma formation, and provide additional safety data indicating an elevated risk for cardiovascular and thrombotic adverse events, particularly for patients with preexisting atherosclerotic heart disease.

NSAIDs and colorectal cancer prevention

This article discusses the merits and limits of nonsteroidal antiinflammatory drugs (NSAIDs), including cyclooxygenase (COX)-2 inhibitors, for colorectal cancer prevention. The suppressive effect of NSAIDs on colorectal tumors has been recognized since as early as 1981. The chemopreventive effect of NSAIDs on colorectal tumors in relationship to the inhibition of prostaglandin synthesis is reviewed first. Then, the results of a randomized double-blind clinical test that examined the regressive effect of a COX-2-specific inhibitor on adenoma of familial adenomatous polyposis (FAP) are presented. Other similar trials are also reviewed. The clinical guideline for the use of aspirin, NSAIDs, and COX-2 inhibitors for primary prevention of colorectal cancer that was prepared for the U.S Preventive Services Task Force is introduced. These results suggest that a higher dose of COX-2 inhibitors has a suppressive effect on adenoma of the colon and rectum, although a moderate clinical dose of COX-2 inhibitors does not induce clinically effective suppression of adenoma. In the future, NSAIDs may be tried in combination with other materials to prevent colorectal cancer.

Prognostic and therapeutic implications of Apc mutations in colorectal cancer

The adenomatous polyposis coli gene (Apc) is mutated in most colorectal cancers. The multifunctional character of the Apc protein in the regulation of beta-catenin-mediated gene transcription and cytoskeletal proteins has been well described. An important question is how this protein affects the behaviour of cells within a tumour and how its mutational status influences the prognosis for these tumours. Here we provide an overview of the functions of Apc and examine how this information can be used in the prognosis and development of directed therapy in colorectal cancer.

Tumor Initiation Inhibition Through Inhibition COX-1 Activity of a Traditional Korean Herbal Prescription, Geiji-Bokryung-Hwan, in Human Hepatocarcinoma Cells

Some Korean and oriental herbal prescriptions used for a syndrome expressed as chest paralysis and heartache are thought to be effective for angina pectoris. We investigated the effects of an oriental medicinal prescription, Geiji-Bokryung-Hwan (GBH) consisting of herbs of Cinnamomi Ramulus, Poria Cocos Hoelen (Pachymae Fungus), Moutan Cortex Radicis, Paeoniae Radix, and Persicae Semen, on growth-inhibitory activity and cancer chemopreventive activity in assays representing three major stages of carcinogenesis. The GBH was found to act as an potent inhibitor of cyclooxygenase (COX)-1 only but not as COX-2 inhibitor. Furthermore, the extract mediated anti-inflammatory effects and inhibited COX-associated hydroperoxidase functions (anti-promotion activity). Inhibitory effect of the GBH on the growth of cancer cell lines such as HepG2 cell and Hep3B cell was shown. These data suggest that GBH extracts merit investigation as a potential cancer chemopreventive agent in humans, especially in hepatological cancers.

Pathophysiology, clinical presentation, and management of colon cancer

Colon cancer is believed to arise from two types of precursor polyps via two distinct pathways: conventional adenomas by the conventional adenoma-to-carcinoma sequence and serrated adenomas according to the serrated adenoma-to-carcinoma theory. Conventional adenomas arise from mutation of the APC gene; progression to colon cancer is a multistep process. The fundamental genetic defect in serrated adenomas is unknown. Environmental factors can increase the risk for colon cancer. Advanced colon cancer often presents with symptoms, but early colon cancer and premalignant adenomatous polyps commonly are asymptomatic, rendering them difficult to detect and providing the rationale for mass screening of adults over age 50.

Chemoprevention of Scutellaria bardata on human cancer cells and tumorigenesis in skin cancer

Scutellaria barbata D. Don (Lamiaceae) (SB) is a perennial herb, which is natively distributed throughout Korea and southern China. This herb is known in traditional Chinese medicine as Ban-Zhi-Lian and in traditional Korean medicine as Banjiryun. SB has been used as an antiinflammatory and antitumor agent. The SB showed strong growth-inhibitory activity and cancer chemopreventive activity in assays representing three major stages of carcinogenesis. The SB was found to act as an antimutagen; it mediated antiinflammatory effects; inhibited cyclooxygenase and hydroperoxidase functions (antipromotion activity). In addition, SB inhibited the development of preneoplastic lesions in carcinogen-treated mouse mammary glands in culture and inhibited tumorigenesis in a mouse skin cancer model. On the other hand, an inhibitory effect of SB on the growth of gynecological cancer cell lines such as HeLa cell and human ovary cancer (HOC) was shown. When HOC cells were treated with SB, the expression of cyclooxygenase-2 was inhibited. These data suggest that SB merits investigation as a potential cancer chemopreventive agent in humans, especially in gynecological cancers.

NSAIDs and cancer prevention: targets downstream of COX-2

Preclinical and clinical studies have clearly shown a benefit of nonsteroidal anti-inflammatory drug (NSAID) use in reducing cancer risk. However, the adverse gastrointestinal and cardiovascular side effects associated with NSAIDs and COX-2 selective inhibitors (coxibs) have provoked more scrutiny of the precise role of specific downstream mediators in the prostaglandin (PG) signaling cascade. NSAIDs and coxibs inhibit PG biosynthesis. One of the PGs produced at high levels in the tumor microenvironment is PGE(2), which is thought to play a major role in cancer progression. Thus, a better understanding of PGE(2) signaling could enable identification of novel and safer therapeutic targets downstream of the cyclooxygenase enzymes. We review the emerging molecular mechanisms by which COX-2-derived PGE(2) is involved in cancer progression and delineate potential opportunities for development of novel pharmacologic approaches utilizing this pathway.

Prevention of breast cancer: current state of the science and future opportunities

Despite significant progress in breast cancer treatment, mammary tumours still represent the second most frequent cause of cancer-related death in women in the US, with > 211,000 new cases in 2005; however, an expanding range of options for early diagnosis and more reliable risk assessment offers new alternatives for disease control by cancer prevention. Completed large studies with the classical selective estrogen receptor modulator (SERM) tamoxifen have demonstrated that preventing breast cancer pharmacologically is now possible. Novel SERMs, aromatase inhibitors and gonadotropin-releasing hormone agonists targeting hormonal pathways are being tested in clinical trials, revealing the potential for dramatic reductions in tumour incidence with minimal side effects; however, SERMs and aromatase inhibitors are effective only against estrogen receptor-positive tumours, thus chemopreventive drugs targeting other critical signalling pathways (such as retinoids, selective COX inhibitors and tyrosine kinase inhibitors) may provide a means to prevent estrogen receptor-negative breast cancer. In the future, hormonal and estrogen receptor-independent agents may be combined to prevent the development of all mammary tumours. This article reviews the current and novel strategies for breast cancer prevention.

Surveillance and management of upper gastrointestinal disease in Familial Adenomatous Polyposis

Almost all patients affected by Familial Adenomatous polyposis (FAP) will develop foregut as well as hindgut polyps, and following prophylactic colectomy duodenal cancer constitutes one of the leading causes of death in screened populations. Without prophylactic colectomy, FAP patients predictably develop colorectal cancer, but the lifetime risk of upper gastrointestinal cancer is lower, estimated at approximately 5%. Management of the upper gastrointestinal cancer risk is one of the greatest challenges facing clinicians involved in the care of Polyposis families, and with improved survival following prophylactic colectomy, the burden of foregut disease (particularly duodenal adenomatosis) will increase. Until recently, the value of upper gastrointestinal surveillance in FAP populations has been contentious, but with improved understanding of the natural history coupled with developments in surgery, interventional endoscopy and medical therapy, treatment algorithms for duodenal adenomatosis in FAP are becoming clearer.

The role of cyclooxygenase-2 and prostaglandins in colon cancer

The temporal association between loss of function of the tumor suppressor adenomatous polyposis coli (APC) and overexpression of cyclooxygenase 2 (COX-2) has been demonstrated in vivo and has led to the hypothesis that APC regulates COX-2 expression. This could potentially occur through a variety of mechanisms including the well-characterized ability of APC to negatively regulate Wnt signaling and decrease expression of target genes. However, recent findings suggest that the products of COX-2 elicit effects that occur upstream of the beta-catenin/TCF/LEF pathway. This review will focus on the regulation of COX-2 by APC and the interplay between COX-2 and the Wnt signaling pathway.