Stromal iodothyronine deiodinase 2 (DIO2) promotes the growth of intestinal tumors in ApcΔ716 mutant mice

Iodothyronine deiodinase 2 (DIO2) converts the prohormone thyroxine (T4) to bioactive T3 in peripheral tissues and thereby regulates local thyroid hormone (TH) levels. Although epidemiologic studies suggest the contribution of TH to the progression of colorectal cancer (CRC), the role of DIO2 in CRC remains elusive. Here we show that Dio2 is highly expressed in intestinal polyps of ApcΔ716 mice, a mouse model of familial adenomatous polyposis and early stage sporadic CRC. Laser capture microdissection and in situ hybridization analysis show almost exclusive expression of Dio2 in the stroma of ApcΔ716 polyps in the proximity of the COX-2-positive areas. Treatment with iopanoic acid, a deiodinase inhibitor, or chemical thyroidectomy suppresses tumor formation in ApcΔ716 mice, accompanied by reduced tumor cell proliferation and angiogenesis. Dio2 expression in ApcΔ716 polyps is strongly suppressed by treatment with the COX-2 inhibitor meloxicam. Analysis of The Cancer Genome Atlas data shows upregulation of DIO2 in CRC clinical samples and a close association of its expression pattern with the stromal component, consistently with almost exclusive expression of DIO2 in the stroma of human CRC as revealed by in situ hybridization. These results indicate essential roles of stromal DIO2 and thyroid hormone signaling in promoting the growth of intestinal tumors.

Chemoprevention in Patients with Peutz-Jeghers Syndrome: Lessons Learned

LESSONS LEARNED

Motivating patients to enroll in chemopreventive studies is challenging.Chemoprevention with toxic drugs is not feasible.

BACKGROUND

LKB1 mutations are the underlying genetic abnormality causing Peutz-Jeghers syndrome (PJS) and are a potential target for everolimus. In this phase II study, the efficacy of everolimus on polyp and tumor growth in PJS patients was investigated.

METHODS

Adult patients with a proven LKB1 mutation and who were suitable for everolimus treatment were included in two different PJS cohorts: (a) patients with unresectable malignancies and (b) patients with high-risk polyps. Treatment in both groups was oral everolimus, 10 mg daily. Response rates were primary endpoints for both cohorts.

RESULTS

Between October 2011 and April 2016, only two patients were enrolled, one in each cohort. A 49-year-old patient with advanced pancreatic cancer in cohort 1 was progressive after 2 months. A 52-year-old male patient in cohort 2 experienced severe toxicity and refused treatment after 4 months, even though endoscopy suggested stabilization of polyps. Adverse events included dental inflammations, mucositis, and rash. In 2016, the trial was aborted for lack of accrual, despite extensive accrual efforts in an area where PJS is highly prevalent and care is highly centralized.

CONCLUSION

Due to accrual problems, no conclusions can be drawn about the value of everolimus in PJS treatment, questioning the feasibility of this agent for chemoprevention.

Impact of Acetazolamide, a Carbonic Anhydrase Inhibitor, on the Development of Intestinal Polyps in Min Mice

Colorectal cancer is a common cancer worldwide. Carbonic anhydrase (CA) catalyzes the reversible conversion of carbon dioxide to bicarbonate ion and a proton, and its inhibitor is reported to reduce cancer cell proliferation and induce apoptosis. Therefore, we asked whether acetazolamide, a CA inhibitor, could inhibit intestinal carcinogenesis. Five-week-old male Apc-mutant mice, Min mice, were fed a AIN-76A diet containing 200 or 400 ppm acetazolamide. As a result, acetazolamide treatment reduced the total number of intestinal polyps by up to 50% compared to the control group. In addition, the acetazolamide-treated group had low cell proliferation and a high apoptosis ratio in the intestinal polyp epithelial cells. Moreover, the mRNA expression level of proinflammatory cytokines, such as IL-6, involved in the cell proliferation was decreased in the polyp part of the acetazolamide-treated group. Next, we examined the effects of acetazolamide on the activation of several transcriptional factors (AP-1, HIF, HSF, NF-κB, NRF2, p53, and STAT3) using a reporter gene assay in human colon cancer cells, Caco-2 cells. Among the examined transcriptional factors, NRF2 transcriptional activation was strongly induced. NRF2-targeting genes, γGCS, GPx1, HO-1, and NQO-1, were also elevated in the intestinal polyps of acetazolamide-treated Min mice. Our results suggested that CA is involved in intestinal carcinogenesis. Acetazolamide could inhibit polyp formation through suppressing local/general cytokine levels, i.e., IL-6, via NRF2 activation.

Lovastatin, but not orlistat, reduces intestinal polyp volume in an ApcMin/+ mouse model

The statins, inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCoAR) and orlistat, an inhibitor of fatty acid synthase (FAS), inhibit tumor cell growth by restricting cholesterol and fatty acid synthesis, respectively. We previously demonstrated that an omega (ω)-3 polyunsaturated fatty acid (PUFA)- or olive oil-enriched diet reduced the polyp number and volume in ApcMin/+ mice. This phenomenon was associated with a significant inhibition of FAS and HMGCoAR, as well as an increase in the estrogen receptor (ER)β/α ratio. Herein, we evaluated the effect of lovastatin and orlistat on polyp development and ER expression in ApcMin/+ mice, in order to confirm previous data obtained with ω‑3-PUFAs and olive oil. As expected, the use of lovastatin and orlistat significantly reduced HMGCoAR and FAS enzymatic activities and gene expression in colonic tissues, but did not affect the number of intestinal polyps, while there was a statistically significant reduction in polyp volume only in the mouse group treated with lovastatin. In the mice receiving orlistat, we observed a significant increase in cell proliferation in the polyp tissue, as well as enhanced expression of ERα. Moreover, the overexpression of ERα was associated with a statistically significant increase in PES1, Shh and Gli1 protein levels, considered ERα-related molecular targets.

Targeting cyclooxygenase-2 and the epidermal growth factor receptor for the prevention and treatment of intestinal cancer

Clinical and animal studies indicate a role for cyclooxygenase-2 (COX-2) and the epidermal growth factor receptor (EGFR) in the development and progression of intestinal polyps and cancers. Although this combination of enzyme inhibition has shown synergy in intestinal polyp and tumor models, the exact mechanism for these effects remains undefined. Therefore, we sought to define the molecular mechanisms through which this process occurs. We observed a significant reduction in the number and size of small intestinal polyps in APC(min+/-) mice treated with either celecoxib (a selective COX-2 inhibitor) or erlotinib (Tarceva, an EGFR inhibitor). However, in combination, there was an overall prevention in the formation of polyps by over 96%. Furthermore, we observed a 70% reduction of colorectal xenograft tumors in mice treated with the combination and microarray analysis revealed genes involved in cell cycle progression were negatively regulated. Although we did not observe significant changes in mRNAs of genes with known apoptotic function, there was a significant increase of apoptosis in tumors from animals treated with the combination. The inhibition of EGFR also induced the down-regulation of COX-2 and further inhibited prostaglandin E2 formation. We observed similar effects on the prevention of intestinal adenomas and reduction of xenograft tumor volume when nonselective COX inhibitors were used in combination with erlotinib. Together, these findings suggest that the inhibition of both COX-2 and EGFR may provide a better therapeutic strategy than either single agent through a combination of decreased cellular proliferation and prostaglandin signaling as well as increased apoptosis.

Inhibiting vascular endothelial growth factor receptor-2 signaling reduces tumor burden in the ApcMin/+ mouse model of early intestinal cancer

The Apc(Min/+) mouse model is a clinically relevant model of early intestinal cancer. We used AZD2171, an oral, highly potent and selective vascular endothelial growth factor (VEGF) signaling inhibitor, to investigate the role of VEGF receptor-2 (VEGFR-2) signaling in adenoma development and growth in Apc(Min/+) mice. AZD2171 (5 mg/kg body wt/day) was administered once daily for 28 days to 6-week-old (early-intervention) or 10-week-old (late intervention) mice. In the early-intervention study, AZD2171 reduced the number of macroscopic polyps in the small bowel and colon. Macropolyp diameter was lower in the small bowel, but remained unchanged in the colon. In animals receiving AZD2171, microscopic evaluation of the small intestine showed a significant reduction in the number of larger lesions. In the late-intervention study, AZD2171 treatment reduced macropolyp diameter (but not number) in the small intestine. Microscopic analysis revealed that AZD2171 significantly reduced the number of larger micropolyps in the small bowel, with no large micropolyps present in the colon. AZD2171 treatment had no effect on microvessel density or localization of beta-catenin staining in adenomas or non-tumor intestinal tissue, but significantly reduced the number of cells expressing VEGFR-2 mRNA. In conclusion, the effects of AZD2171 in the small intestine of Apc(Min/+) mice are consistent with an antiangiogenic mechanism of action, limiting growth of adenomas to < or =1 mm. These data also suggest that an early step in adenoma development may depend on VEGFR-2 signaling. Together, these results indicate that VEGFR-2 signaling may play key roles in the development and progression of intestinal adenomas.

Cancer chemoprevention of intestinal polyposis in ApcMin/+ mice by sulforaphane, a natural product derived from cruciferous vegetable

Sulforaphane (SFN) is an isothiocyanate that is present abundantly in widely consumed cruciferous vegetables and has a particularly high content in broccoli and cauliflower. It has been shown to be an effective inhibitor of some carcinogen-induced cancers in rodents. Here, we investigated the chemopreventive efficacy of SFN in the ApcMin/+ mouse model. ApcMin/+ mice were fed with diet supplemented with two different dose levels of SFN (300 and 600 p.p.m.) for 3 weeks. Our results clearly demonstrated that ApcMin/+ mice fed with SFN-supplemented diet developed significantly less and smaller polyps with higher apoptotic and lower proliferative indices in their small intestine, in a SFN dose-dependent manner. In addition, immunohistochemical (IHC) staining of the adenomas indicated that SFN significantly suppressed the expression of phosphorylated c-Jun N-terminal kinase (p-JNK), phosphorylated extracellular signal-regulated kinases (p-ERK) and phosphorylated-Akt (p-Akt), which were found to be highly expressed in the adenomas of ApcMin/+ mice. In contrast, expression of two important biomarkers of the Wnt signaling pathway, beta-catenin and cyclin-D1 was unaffected by SFN treatment. Measurement of SFN and its metabolite SFN-GSH in the small intestine using LC-MS indicates that the concentrations between 3 and 30 nmol/g are required to prevent, or retard adenoma formation in the gastrointestinal tract of ApcMin/+ mice.

Pharmacogenomics of cancer chemopreventive isothiocyanate compound sulforaphane in the intestinal polyps of ApcMin/+ mice

Sulforaphane (SFN) is an isothiocyanate that is present in widely consumed vegetables. Previous studies have shown that SFN is effective in preventing carcinogenesis induced by carcinogens in rodents. Recently it was found that SFN could also suppress the growth of intestinal polyps in the ApcMin/+ mouse. In the present study, the acute effect of SFN on the gene expression profile in small intestinal polyps of ApcMin/+ mice using Affymetrix microarray was performed. SFN is a strong inducer for phase II drug metabolizing enzymes, which is believed to contribute to its chemopreventive properties. However, the results show that genes involved in apoptosis, cell growth and maintenance rather than the predicted phase II genes were modulated. The proapoptotic genes including MBD4, TNFR-7 and TNF (ligand)-11 were up-regulated while pro-survival genes including cyclin-D2, integrin-beta1 and Wnt-9A were down-regulated. Interestingly, two genes potentially involved in colorectal carcinogenesis, 15-LOX and COX-2 were found to be increased and decreased, respectively. In conclusion, the results show, for the first time, that chemopreventive agents such as SFN regulate different set of genes involving apoptosis, cell growth/maintenance and inflammation in the small intestinal polyps of ApcMin/+ mice, which could contribute to the overall chemopreventive pharmacological effects.

In vivo fluorescence diagnostics and photodynamic therapy of gastrointestinal superficial polyps with aminolevulinic acid. A clinical and spectroscopic study

In the present study initial results of clinical study related to the treatment of patients having different types of precancerous lesions in the area of esophagus, stomach and intestine by photodynamic therapy (PDT) based on aminolevulinic acid (ALA-PDT) are reported. The procedure was performed by laser fibre system with the light guides introduced through biopsy channel of an endoscope. In addition, in vivo fluorescent diagnostics and spectral analyses of biopsies were performed. Each patient had a positive response to therapy. In two cases there was a total response and in other five cases more than sixty percent of suspected area was removed. Additionally, sigilocellular carcinoma of stomach was revealed in one case. It appears from the results of this study, that the treatment of precancerous lesions with ALA-PDT could be successful treatment modality.

Topical budesonide for treating giant rectal pseudopolyposis

Pseudopolyps are a frequent finding in the course of inflammatory bowel disease. They are non-neoplastic lesions resulting from a regenerative and healing process that leaves inflamed colonic mucosa in polypoid configuration. Data about their management is lacking. "Giant" pseudopolyps can be mistaken for adenocarcinomas and, as they rarely regress with medical management alone, a surgical resection is often required. A case ofgiantpseudopolyposis treated non-surgically, in a patient with concomitant ulcerative colitis and chronic hepatitis B, is reported, representing a co-morbidity complicating an eventual conservative treatment. The clinical implementation of topical budesonide was originally tested, resulting in clinical, endoscopic and histological remission. Budesonide seems a promising therapy for IBD, particularly when a comorbidity with viral hepatitis exist.

Potential off-label use of infliximab in autoimmune and non-autoimmune diseases: a review

TNF-alpha is a crucial cytokine in the establishment and maintenance of inflammation in multiple autoimmune and non-autoimmune disorders. A number of large placebo-controlled trials have shown that infliximab, a chimeric monoclonal antibody against TNF-alpha, is effective and well-tolerated in patients with Crohn's disease and rheumatoid arthritis (RA) and has become a widely used treatment for these diseases. More recent controlled trials have also shown the effectiveness of TNF-alpha blockers in psoriasis, psoriatic arthritis, and ankylosing spondylitis. The results of clinical trials, open-label studies, and case studies indicate that TNF inhibitors (alone or in combination with other protocols) look very promising for the treatment of a variety of other conditions, including uveitis, sarcoidosis, Sjögren's syndrome (SS), Behcet's syndrome, vasculitis, and graft versus host disease. There is a rationale for using TNF blockade even in systemic lupus erythematosus, a prototype of autoantibody-mediated disease, and a pilot study seems to confirm this potential effective approach. The neutralisation of TNF might therefore play a role in the treatment of many autoimmune and non-autoimmune disorders other than Crohn's disease or RA. We here review the current and prospective roles of infliximab in the treatment of autoimmune diseases and other conditions that do not currently have FDA or EMEA approval.

Chemoprevention of colorectal cancer

Colorectal cancer is a disease with a high mortality rate and it has been increasing in prevalence worldwide. Chemoprevention, as well as primary and secondary prevention, for colorectal cancer have attracted much attention. Many chemopreventive trials have been performed, and several agents, including nonsteroidal antiinflammatory drugs, such as aspirin and sulindac, cyclooxygenase-2 selective inhibitors, such as celecoxib, vitamin D, folate, and calcium, have been shown to have some effect. In these chemopreventive trials, the targeted lesions used for evaluation were mainly polyps. However, the chemopreventive effects of some agents on polyps may require several years to evaluate. Further, larger polyps may not be susceptible to chemopreventive agents. Aberrant crypt foci (ACF) are tiny lesions at the earliest stage of colorectal carcinogenesis, which consist of large, thick crypts identified by dense, methylene blue staining. We succeeded in identifying human ACF in situ using magnifying endoscopy and found that the number of ACF, particularly dysplastic ACF, increased significantly from normal subjects to adenoma patients and then to cancer patients. We also found that the number, size, and dysplastic features of ACF are significantly correlated with the number of adenomas in adenoma patients. Thus, it was surmised that ACF are precursor lesions of the adenoma-carcinoma sequence in humans and that ACF may be the most appropriate lesions as targets for chemoprevention. We have shown that the number of ACF was significantly reduced in patients treated with sulindac. We are currently proceeding with a randomized, double-blind, chemopreventive trial targeting ACF.

Prevention of colorectal cancer through the use of COX-2 selective inhibitors

Colorectal cancer is a major cause of morbidity and mortality accounting for an estimated 550,000 deaths annually worldwide. Colonic neoplasia develops in a stepwise fashion progressing from normal mucosa to adenomatous polyps to carcinoma, a process that takes years, thereby providing a prime opportunity for intervention. Although early detection by fecal occult blood testing and sigmoidoscopy can decrease the risk of cancer-related death by 20-30%, most persons never undergo appropriate screening. Population-based studies have previously determined that long-term ingestion of aspirin or other nonsteroidal antiinflammatory drugs (NSAIDs) leads to a 40-50% reduction in mortality. from colorectal cancer. These observational studies fueled subsequent mechanistic investigations that led to the identification of a molecular target, cyclooxygenase-2 (COX-2). COX-2 has tumor-promoting properties. Expression of COX-2 is virtually undetectable in normal intestinal mucosa, but is increased in approximately 50% of colonic adenomas and in 90% of colorectal carcinomas. Experimental studies in mice have revealed that genetic ablation or pharmacologic inhibition of COX-2 attenuates the number and size of intestinal polyps that develop in animals harboring a mutation in Apc, which confers an increased risk for intestinal neoplasia. Recent clinical studies using specific COX-2 inhibitors have shown that these compounds can: (1) reduce intestinal polyp burden in patients with familial adenomatous polyposis; (2) prevent the occurrence and/ or recurrence of colorectal adenomas and cancers; and (3) negatively regulate angiogenesis in colorectal cancer liver metastases. Compared to nonselective NSAIDs, COX-2 specific inhibitors cause substantially fewer gastrointestinal side effects. These findings indicate that a widely used and relatively safe class of drugs may represent a viable and effective anticancer strategy for a disease that causes over a half-million deaths per year.

A rare case of multiple lymphomatous polyposis with widespread involvement of the gastrointestinal tract

Multiple lymphomatous polyposis (MLP) is an uncommon type of primary non-Hodgkin gastrointestinal (GI) B-cell lymphoma characterized by the presence of multiple polyps along the GI tract. Malignant cells of MLP have mantle cell characteristics and thus are considered to be the counterpart of the mantle cell lymphoma (MCL) in the GI tract. Since 1961, no more than 70 well-documented cases have been published. We report the case of 53-year-old man diagnosed as having MLP. The patient presented with diffuse abdominal pain, chronic lower GI bleeding, peripheral lymphadenopathy, and weight loss. The lymphomatous polyps extended from the esophagus to the rectum, with bone marrow infiltration. Immunohistologic findings were characteristic of MCL. The patient was treated with a combined cyclophosphamide, vincristine, and prednisone chemotherapy regimen, resulting in a partial response.

Suppression of intestinal polyposis in Mdr1-deficient ApcMin/+ mice

Aberrant transactivation of a certain set of target genes by the beta-catenin and T-cell factor/lymphoid enhancer factor complex has been considered crucial for the initiation of intestinal tumorigenesis. The human multidrug resistance (MDR)1 (ABCB1) gene contains multiple beta-catenin-T-cell factor4-binding elements in its promoter and is one of the immediate targets of the complex. In the current study, we have further substantiated the biological involvement of MDR1 in intestinal tumorigenesis based on the following evidence: (a) aberrant induction of the Mdr1a (Abcb1a) gene product, P-glycoprotein, associated with nuclear accumulation of the beta-catenin protein, was observed even in nascent microscopic adenomas of Min mice; (b) Mdr1-deficient Min (Apc(Min/+)Mdr1a/b(-/-)) mice developed significantly fewer intestinal polyps than did Apc(Min/+)Mdr1a/b(+/+) mice; and (c) Inhibitors of P-glycoprotein, verapamil, and cyclosporin A had a suppressive effect on the in vitro polypoid growth of IEC6 expressing stabilized (DeltaN89) beta-catenin protein. Inhibitors of P-glycoprotein may be included in a novel class of chemopreventive agents against colorectal carcinogenesis.

Pharmacological management of Cronkhite-Canada syndrome

Cronkhite-Canada syndrome (CCS) is a rare, non-inherited gastrointestinal polyposis syndrome associated with characteristic ectodermal abnormalities. A number of potentially life-threatening complications including malnutrition, gastrointestinal bleeding and infection may occur in affected patients and CCS is fatal in many cases. The optimal therapy for CCS is not known but several treatment options have been described. Nutritional support, antibiotics, corticosteroids, anabolic steroids, histamine-receptor antagonists and surgical treatment have all been used with varying degrees of success. Unfortunately, controlled therapeutic trials have not been possible because of the rarity of the disease. Most recently, a combination regimen using histamine-receptor antagonists, cromolyn sodium, prednisone and suppressive antibiotics has been described. The reported treatment options and rates of success are reviewed.

A randomised, double blind, placebo controlled study of celecoxib, a selective cyclooxygenase 2 inhibitor, on duodenal polyposis in familial adenomatous polyposis

BACKGROUND

Non-selective cyclooxygenase (COX) inhibitors (non-steroidal anti-inflammatory drugs) inhibit large bowel carcinogenesis in patients with familial adenomatous polyposis (FAP). Their role in the duodenum of these patients is less certain. The disease modifying activity of specific COX-2 inhibitors has not been explored in humans.

PATIENTS AND METHODS

This was a randomised, double blind, placebo controlled study of celecoxib (100 mg twice daily (n=34) or 400 mg twice daily (n=32)) versus placebo (n=17), given orally twice daily for six months to patients with FAP. Efficacy was assessed qualitatively by blinded review of shuffled endoscopy videotapes comparing the extent of duodenal polyposis at entry and at six months and quantitatively by measurement of the percentage change in duodenal area covered by discrete and plaque-like adenomas from photographs of high and low density polyposis.

RESULTS

Shuffled and blinded video review showed a statistically significant effect of 400 mg twice daily celecoxib compared with placebo treatment (p=0.033) with all five independent observers scoring a beneficial effect. Overall, patients taking celecoxib 400 mg twice daily showed a 14.5% reduction in involved areas compared with a 1.4% for placebo (p=0.436). However, patients with clinically significant disease at baseline (greater than 5% covered by polyps) showed a 31% reduction in involved areas with celecoxib 400 mg twice daily compared with 8% on placebo (p=0.049).

CONCLUSIONS

A panel of five endoscopists found a significant reduction in duodenal polyposis after six months of treatment with celecoxib 400 mg twice daily. COX-2 inhibition may help this otherwise untreatable condition.

Medical management of Cronkhite-Canada syndrome

We report the case of a patient with Cronkhite-Canada syndrome (CCS) successfully treated with combination medical therapy. This rare, noninherited gastrointestinal polyposis syndrome is associated with characteristic ectodermal abnormalities. The etiology and pathogenesis of CCS are not known. No medical therapy has been shown to be consistently effective, and the disease is usually fatal. The patient described herein was successfully treated with a novel combination regimen consisting of H1- and H2-receptor antagonists, cromolyn sodium, prednisone, and suppressive antibiotics. This regimen has resulted in sustained improvement in symptoms, and follow-up endoscopy has shown regression of the diffuse polyposis. Our patient's response to such therapy may provide insight into the optimal treatment for CCS.

Cronkhite-Canada syndrome. A case of sustained partial-remission

A case of Cronkhite-Canada syndrome is described. Few cases have been published and in most patients the prognosis is poor. A variety of medical measures have been attempted in those in whom remission has been reported. In the patient presented here, a sustained partial-remission has been achieved with steroids.

Randomized, placebo-controlled trial of gastric acid-lowering therapy on duodenal polyposis and relative adduct labeling in familial adenomatous polyposis

PURPOSE

Bile has been implicated in the pathogenesis of duodenal polyps in patients with familial adenomatous polyposis. In vitro experiments have shown that familial adenomatous polyposis bile is capable of producing DNA adducts. This effect can be ameliorated by increasing the pH of the incubate. The aim of this double-blind randomized placebo-controlled trial was to examine the effect of oral ranitidine on duodenal polyposis in a group of patients with familial adenomatous polyposis.

METHODS

Twenty-six patients with familial adenomatous polyposis were randomly assigned to ranitidine 300 mg daily or placebo for six months after baseline endoscopy. Polyp counts were performed and biopsy specimens taken to detect DNA adducts by 32P-postlabeling.

RESULTS

No difference was seen in polyp numbers (P = 0.9) or relative adduct labeling (P = 0.7) after treatment with ranitidine or placebo.

DISCUSSION

Acid suppression therapy does not seem to improve duodenal polyposis despite in vitro findings. On the other hand, ranitidine does not exacerbate actual (or markers of) neoplasia in this highly tumor-prone condition.

Suppression of intestinal polyps in Msh2-deficient and non-Msh2-deficient multiple intestinal neoplasia mice by a specific cyclooxygenase-2 inhibitor and by a dual cyclooxygenase-1/2 inhibitor

Epidemiological studies suggest that nonsteroidal anti-inflammatory agents decrease the risk of colorectal cancer. This is believed to be mediated, at least in part, by inhibition of cyclooxygenase (COX) activity. There are two COX isoenzymes, namely the constitutively expressed COX-1 and the inducible COX-2. COX-2 is overexpressed in adenomas and colorectal cancers, and COX-2-specific inhibitors have been shown to inhibit intestinal polyps in Apc(Delta716) mice more effectively than dual COX-1/COX-2 inhibitors such as sulindac. Various Apc knockout mice, including the multiple intestinal neoplasia (Min) mouse and the Apc(Delta716) mouse, are limited by their lack of large numbers of colonic adenomas and aberrant crypt foci, the putative precursors of large-bowel polyps and cancers. Our DNA mismatch-repair-deficient Min mouse model (Apc+/-Msh2-/-) has genetic features of both familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer, and most importantly, rapidly develops numerous small- and large-bowel adenomas, as well as colonic aberrant crypt foci. The purpose of this study was to determine the effects of COX inhibitors on intestinal adenomas and colonic aberrant crypt foci in this accelerated polyposis, mismatch-repair-deficient Min mouse model, in addition to a standard Min mouse model. Weanling Apc+/-Msh2-/- and Min mice were fed diets containing no drug, sulindac, or a specific COX-2 inhibitor (MF-tricyclic). Apc+/-Msh2-/- and Min mice were sacrificed after 4 weeks and 5 months on diet, respectively. Apc+/-Msh2-/- mice treated with MF-tricyclic had significantly fewer small-bowel polyps (mean +/- SD, 178 +/- 29) compared with mice on sulindac (278 +/- 80), or control diet (341 +/- 43; P < 0.001). There was no difference in numbers of large-bowel polyps or aberrant crypt foci in mice in the three groups. MF-tricyclic was also effective in reducing both small- and large-bowel polyps in Min mice. Western analysis demonstrated COX-2 expression in both large- and small-bowel polyps from mice of both genotypes. This study demonstrates that a specific COX-2 inhibitor is effective in preventing small-bowel polyps in mismatch-repair-deficient Min mice and both small- and large-bowel polyps in standard Min mice. Therefore, specific COX-2 inhibitors may be useful as chemopreventive and therapeutic agents in humans at risk for colorectal neoplasia.

Trial endpoints for drug approval in oncology: Chemoprevention

As with other drugs, new drug applications for marketing approval of chemopreventive drugs must include data from adequate and well-controlled clinical trials that demonstrate effectiveness and safety for the intended use. This article summarizes the regulatory requirements for traditional marketing approval, as well as for approval under the accelerated approval regulations. Unlike traditional approval, accelerated approval is based on a surrogate endpoint that is reasonably likely to predict clinical benefit. Discussions with the Food and Drug Administration (FDA) regarding the validity of trial endpoints that may serve as surrogates for clinical benefit for accelerated approval should take place as early as possible in drug development. Meetings with the FDA to discuss these issues may be requested throughout the clinical development of a new drug.

Cronkhite Canada syndrome

Cronkhite Canada syndrome is an acquired non-familial syndrome characterised by diffuse gastrointestinal polyposis with alopecia nail dystrophy and hyperpigmentation. There is chronic diarrhoea and protein losing enteropathy. The etiology of this syndrome remains obscure. The rarity of the case prompts this case report.

Preliminary clinical observations on the use of piroxicam in the management of rectal tubulopapillary polyps

Rectal tubulopapillary polyps were diagnosed in eight dogs following proctoscopy and mucosal pinch biopsy. Histological examination of the pinch biopsies revealed evidence of malignant transformation in three of the cases. The remaining cases were diagnosed as benign polyps. Inflammatory changes were observed in four cases. Seven dogs were treated with piroxicam suppositories and one with oral piroxicam. All dogs were re-examined after four to six weeks of piroxicam therapy and the extent of haematochezia, tenesmus and faecal mucus production was reduced in all cases. The owners of seven of the dogs considered the improvement in clinical signs to be good or excellent. Cases with and without evidence of inflammation responded equally well. This finding supports the hypothesis that piroxicam has an antineoplastic effect due to apoptosis and alteration in the cell cycle. Medical management with piroxicam may provide a non-invasive treatment option for dogs with rectal polyp formation in which surgical treatment is likely to be associated with complications such as incontinence, infection and wound breakdown, or where the owner declines such treatment.

Chemopreventive effects of dietary folate on intestinal polyps in Apc+/-Msh2-/- mice

Epidemiological and animal studies (reviewed in Y. I. Kim, J. Nutr. Biochemistry, 10: 66-88, 1999; J. B. Mason and T. Levesque, Oncology, 10: 1727-1743, 1996) suggest that dietary folate intake is inversely related to the risk of colorectal cancer. However, the optimal timing of folate intervention and mechanisms by which folate modulates colorectal carcinogenesis have not been clearly established. A recently developed murine model of intestinal tumorigenesis, which carries a heterozygous mutation in the Apc gene and a null mutation in the Msh2 gene (Apc+/-Msh2-/-), was used to determine the effect of dietary folate on intestinal tumorigenesis. Apc+/- Msh2-/- mice were randomized to receive either 0 or 8 mg of folate/kg diet starting at either 3 or 6 weeks of age. The 3- and 6-week diet starts represent intervention before and after the establishment of neoplastic foci, respectively. At 11 weeks of age, mice were killed, and the small intestines and colons were analyzed for adenomas and aberrant crypt foci (ACF). Serum folate concentrations were determined by a standard microbiological assay. Genomic DNA methylation was assessed by in vitro [3H]methyl incorporation into hepatic DNA and by a methyl-sensitive restriction digestion method. Microsatellite instability was determined in matched normal and polyp DNA from the small intestine and colon at 5 loci. Serum folate concentrations accurately reflected dietary folate levels (P < 0.005). Folate supplementation, started before the establishment of neoplastic foci, significantly decreased the number of small intestinal adenomas (by 2.7-fold; P = 0.004) and colonic ACF (by 2.8-fold; P = 0.028) and colonic adenomas (by 2.8-fold; P = 0.1) compared with a moderate degree of folate deficiency. In contrast, a moderately folate-deficient diet, started after the establishment of neoplastic foci, significantly reduced the number of small intestinal adenomas (by 4.2-fold; P = 0.001) but had no effect on colonic ACF and adenomas compared with folate supplementation. Genomic DNA methylation and microsatellite instability do not seem to play a major role in folate-modulated intestinal and colonic tumorigenesis in this model. In conclusion, in this murine model, dietary folate supplementation significantly protects against small intestinal and colorectal tumorigenesis if it is provided before the establishment of neoplastic foci However, if it is provided after the establishment of neoplastic foci, dietary folate seems to have an opposite effect. These data suggest that the timing of folate intervention is critical in providing an effective and safe chemopreventive effect on intestinal tumorigenesis. Notwithstanding the limitations associated with this model, our data suggest that the optimal timing of folate intervention must be established before folate supplementation can be used as a safe chemopreventive agent against colorectal cancer.

High-dose chemotherapy and autologous transplantation in lymphomatous polyposis in second remission: three case reports and literature review

Lymphomatous polyposis is a rare primary gastrointestinal lymphoma. It morphologically and immunohistochemically resembles mantle cell lymphoma, with which it shares a disappointing response rate and duration following conventional anthracyclin-containing combination chemotherapy, with a short median survival and virtually no long-term survivors. We report the use of high-dose chemotherapy with autologous stem cell transplantation in second partial remission in three patients with lymphomatous polyposis treated at the Royal Marsden Hospital. All patients achieved a complete response, and one patient remains well and disease-free 64 months following transplantation and 76 months after diagnosis.

Cronkhite-Canada syndrome: report of two cases, biopsy findings in the associated alopecia, and a new treatment option

Two patients with Cronkhite-Canada syndrome (CCS) are reported, both of whom had diffuse alopecia, nail and skin changes, gastrointestinal polyposis, diarrhea, and wasting. A scalp biopsy was performed in one patient, and the specimen showed a marked noninflammatory loss of follicular units, miniaturization of the hair shafts, markedly dilated follicles, and a heavy deposition of glycosaminoglycans in the reticular dermis. This patient responded to prednisone therapy. The other patient was found to have elevated gastric acid levels and responded to ranitidine therapy. The conditions of both patients are now in remission two and six years later, respectively. Our patients have shown a temporally related remission of disease during treatment with prednisone and ranitidine, suggesting that each agent may be effective in CCS. However, randomized placebo-controlled trials are needed to prove the efficacy of these therapies. Further investigation of the histopathologic features of the associated alopecia may determine its cause.

[Polyposis of the gastrointestinal tract as a manifestation of diffuse follicular lymphatic hyperplasia]

HISTORY AND ADMISSION FINDINGS

A 21-year-old previously healthy Turkish man who had been living in Germany for 15 years was admitted because of worsening cramp-like abdominal pain with nausea, vomiting and watery diarrhoea. Palpation elicited diffuse muscular guarding over the entire abdomen and a mass of about 8 cm in the right lower abdomen.

INVESTIGATIONS

Abnormal laboratory results were erythrocyte sedimentation rate (55 mm), C-reactive protein (6.2 mg/dl), total bilirubin (2.1 mg/dl), creatine kinase (137 U/l) and thymidine kinase (5.5 U/l). There was a slight leucocytosis (13,700/microliter) and mild anaemia (haemoglobin 13.4 g/dl) with a normal differential count. Listeria ivanovii was repeatedly cultured from stool. Ultrasonography and computed tomography of the abdomen demonstrated a 6 cm mass in the right lower abdomen, splenomegaly (15.5 x 5 cm) and several lymphomas, up to 1.8 cm in diameter. Endoscopy revealed dense, in part grass-like, polyps, 3 to 6 mm deep, in the mucosa from the terminal ileum to the rectum, and to a lesser extent also in the duodenum. Histological examination of the polyps demonstrated diffuse follicular hyperplasia without evidence of malignancy.

TREATMENT AND COURSE

On antibiotic treatment with ofloxacin (2 x 400 mg intravenously) the symptoms quickly regressed, but the endoscopic findings remained unchanged.

CONCLUSION

Diffuse follicular lymphatic hyperplasia manifested itself in this patient as diffuse gastrointestinal polyposis. Listeria ivanovii cannot be ruled out as a causative factor.

Sulindac for periampullary polyps in FAP patients

BACKGROUND

Gastro-duodenal polyps develop in up to 90% of familial adenomatous polyposis (FAP) patients and periampullary carcinoma is one of the most common extra-colonic malignancies in this syndrome. Periampullary adenomas have been shown to be precursor lesions to periampullary carcinoma. Sulindac, a non-steroidal anti-inflammatory drug, has been reported to cause regression of rectal polyps in FAP patients, however its role in periampullary polyp regression is unclear.

METHODS

In May 1993, a prospective study was begun to evaluate the role of sulindac in prevention of polyp recurrence after resection of large (> 1 cm) duodenal polyps in FAP patients. Eight patients, mean age 50 years (range 35 to 65), with documented large periampullary polyps were placed on sulindac 150 mg twice daily. Prior to enrollment, all patients had their large polyps removed from the periampullary region by interventional endoscopy or by surgery. All patients had multiple small residual duodenal polyps. Follow-up was performed by one experienced endoscopist with a side-viewing video endoscope. Endoscopy was performed 6 monthly. Median follow-up time was 17.5 months (range 10 to 24 months).

RESULTS

In 3 patients, sulindac was discontinued due to side effects: abdominal cramps (n = 2) and upper G-I bleeding (n = 1). None of the patients had regression of small periampullary polyps. In addition, one patient developed an invasive periampullary carcinoma while on sulindac and 3 patients developed large recurrent periampullary polyps requiring further treatment.

SUMMARY

In our experience, sulindac is of no significant benefit for the control of periampullary polyps in FAP. Effective medical treatment of these polyps is still lacking.

Prospective randomized study of sulindac versus calcium and calciferol for upper gastrointestinal polyps in familial adenomatous polyposis

Eighteen patients with familial adenomatous polyposis (FAP) who had previously undergone colectomy but had upper gastrointestinal polyps were studied in a double-blind randomized crossover trial comparing sulindac with calcium and calciferol. Sulindac produced a reduction in the crypt proliferation index in the gastric epithelium of patients but did not significantly affect duodenal mucosa. Calcium with calciferol did not have any effects on crypt proliferation index in patients with FAP.

Angioimmunoblastic lymphadenopathy: an etiology for gastrointestinal lymphomatous polyposis

We describe a case of angioimmunoblastic lymphadenopathy with multiple polyps of the gastrointestinal tract. The patient presented with fever, abdominal mass, ascites, diarrhea, generalized lymphadenopathy, anemia, and marked peripheral eosinophilia. She had multiple polyps in the colon, as well as in the stomach and duodenum. Histology of a colonic polyp showed involvement by angioimmunoblastic lymphadenopathy. The patient responded initially to combination chemotherapy, with total disappearance of polyps. However, she succumbed later to infections. Angioimmunoblastic lymphadenopathy, although rare, should be included as a cause of lymphomatous polyposis of the gastrointestinal tract.

[Malignant lymphomatous polyposis--a rare disease entity of malignant centrocytic lymphoma with characteristic endoscopic appearance]

It is considered as special gastrointestinal manifestation on the nodal centrocytic lymphoma of intermediate malignancy. We demonstrate a 77 years old male patient, who underwent colonoscopy because of rectal bleeding. We found the colonic mucosa dotted with small, flat, lentiform polyps. In the terminal ileum these polyps were much larger. No changes were seen in the esophagus. In the antrum we found flat elevations and in the duodenum again lentiform nodules. Presenting in stage IV of non-Hodgkin's lymphoma the patient was treated with five cycles of combined chemotherapy with prednimustin and mitroxanthrone without side effects. Restaging showed distinct remission of the disease with significant reduction of the mucosal alterations.

Multiple lymphomatous polyposis of the gut

Multiple lymphomatous polyposis is very rare. We report two cases affecting duodenum, small intestine and colon/rectum, both with extensive disease, making radical surgery impossible and chemotherapy the treatment of choice. One patient died 23 days after initial treatment of myocardial infiltration, and the other is still alive 21 months after initial treatment.

Randomized controlled trial of the effect of sulindac on duodenal and rectal polyposis and cell proliferation in patients with familial adenomatous polyposis

Twenty-four patients with familial adenomatous polyposis who had previously undergone prophylactic colectomy and had advanced duodenal polyposis were entered into a randomized trial to assess the effect of the non-steroidal anti-inflammatory drug sulindac on duodenal and rectal polyps. Polyp size and number were assessed by videotaped duodenoscopy (and rectoscopy in 14 patients) at entry and after 6 months of treatment; the tapes were compared by two assessors who were unaware of the randomization and the shuffled chronological order of the recordings. Mucosal cell proliferation was measured by in vitro incorporation of 5-bromo-2'-deoxyuridine. Sulindac therapy was associated with a reduction in epithelial cell proliferation in the duodenum (median labelling index (LI) 15.8 versus 14.4 per cent, P = 0.003) and a trend towards duodenal polyp regression (P = 0.12). In the rectum, cell proliferation showed a marked reduction (median LI 8.5 versus 7.4 per cent, P = 0.018), and significant (P = 0.01) polyp regression was seen. Rectal polyposis was less severe than that in the duodenum and responded more dramatically. Sulindac is a possible treatment for patients in whom rectal polyps have failed to show significant regression after ileorectal anastomosis and who are unsuitable for pouch surgery; it may be useful in early duodenal polyposis or as an adjunct after duodenal clearance.

Effects of vitamin antioxidant supplementation on cell kinetics of patients with adenomatous polyps

Colonic crypt cell proliferation is used as an indicator of risk of colorectal carcinoma. Subjects with adenomatous polyps and cancer have an increased cell proliferation and a shift of the proliferative zone towards the apex of the crypt. Epidemiological and in vitro studies have confirmed a link between vitamins A, E, C, beta-carotene, and colorectal cancer. In vitro bromodeoxyuridine immunohistochemical technique was used to assess the effect of daily oral supplementation with vitamin E (160 mg), vitamin C (750 mg), or beta-carotene (9 mg) on the colonic crypt cell proliferation in patients with adenomatous polyps (n = 40) compared with normal subjects with no colonic disease (n = 20). The patients were given supplementation for one month and colonic biopsy specimens were taken before and at the end of the trial. Patients with adenomatous polyps had a significantly higher mean labelling index per cent than controls (p < 0.001). Vitamin C or beta-carotene supplementation, however, significantly reduced the total proliferation (p < 0.005) whereas vitamin E supplementation had no effect on the colonic crypt cell proliferation. beta-carotene reduced cell proliferation at the base of the crypt only. Vitamin C reduced cell proliferation in all the crypt compartments from the apex to the base to those values seen in age and sex matched controls. These findings indicate that prolonged supplementation with vitamin C may reduce the recurrence of adenomatous polyps.