Adaptogenic flower buds exert cancer preventive effects by enhancing the SCFA-producers, strengthening the epithelial tight junction complex and immune responses.

Microbiome therapy has attracted a keen interest from both research and business sectors. Our lab has been applying this "second genome" platform to assess the functionality of herbal medicines with fulfilling results. In this study, we applied this platform to assess the potential cancer-preventive effects of three selected adaptogenic plants. The flower buds from these plants were used to constitute Preparations SL and FSP according to the receipts of two commonly consumed Chinese medicinal decoctions for gastrointestinal discomfort. Preparation SL contains Sophorae japonica and Lonicerae Japonicae, and Preparation FSP contains Sophorae japonica and Gardenia Jasminoides. SL and FSP extracts significantly (p < 0.001) lowered the polyp burden, as well as the expressions of oncogenic signaling molecules, such as MAPK/ERK, PI3K/AKT, and STAT3 in ApcMin/+ mice. The inflamed gut was alleviated by shifting M1 to M2 macrophage phenotypes and the associated immune cytokines. The other remarkable change was on the extracellular tight junction protein complex, where the occludin, ZO-1, ICAM-1, E-cadherin were significantly (p < 0.05) upregulated while the N-cadherin and ß-catenin were downregulated in the treated mice. The above physiological changes in the gut epithelial barrier were companied with the changes in gut microbiome. The 16S Sequencing data revealed a marked decrease in the potential pathogens (especially Helicobacter species and hydrogen sulfide producing-bacteria) and the increase in beneficial bacteria (especially for species from the genera of Akkermansia, Barnesiella, Coprococcus, Lachnoclostridium, and Ruminococcus). The majority of which were the short-chain fatty acids (SCFAs) producers. Meanwhile SCFAs-sensing G protein-coupled receptors (GPCRs), including GPR41, GPR43, and GPR109a were also significantly upregulated. In a recent report, we proved that the bacteria-derived SCFAs plays an essential role to the anti-cancer effects of the mushroom polysaccharides and saponins in ApcMin/+ mice. In this study, we further demonstrated that butyrate treatment could enhance the extracellular tight junction protein complex as effective as the treatments with SL and FSP to the ApcMin/+ mice. Our findings provide strong evidence of the vital role of the SCFA-producers and their metabolites to the cancer-preventive properties of the SL and FSP preparations.

The REMOTE-control system: a system for reversible and tunable control of endogenous gene expression in mice.

We report here a robust, tunable, and reversible transcription control system for endogenous genes. The REMOTE-control system (Reversible Manipulation of Transcription at Endogenous loci) employs enhanced lac repression and tet activation systems. With this approach, we show in mouse embryonic stem cells that endogenous Dnmt1 gene transcription could be up- or downregulated in a tunable, inducible, and reversible manner across nearly two orders of magnitude. Transcriptional repression of Dnmt1 by REMOTE-control was potent enough to cause embryonic lethality in mice, reminiscent of a genetic knockout of Dnmt1 and could substantially suppress intestinal polyp formation when applied to an ApcMin model. Binding by the enhanced lac repressor was sufficiently tight to allow strong attenuation of transcriptional elongation, even at operators located many kilobases downstream of the transcription start site and to produce invariably tight repression of all of the strong viral/mammalian promoters tested. Our approach of targeting tet transcriptional activators to the endogenous Dnmt1 promoter resulted in robust upregulation of this highly expressed housekeeping gene. Our system provides exquisite control of the level, timing, and cell-type specificity of endogenous gene expression, and the potency and versatility of the system will enable high resolution in vivo functional analyses.

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.

A metagenomic study of the preventive effect of Lactobacillus rhamnosus GG on intestinal polyp formation in ApcMin/+ mice.

AIMS: To investigate the in vivo effects of Lactobacillus rhamnosus GG (LGG) on intestinal polyp development and the interaction between this single-organism probiotic and the gut microbiota therein. METHODS AND RESULTS: The ApcMin/+ mouse model was used to study the potential preventive effect of LGG on intestinal polyposis, while shotgun metagenomic sequencing was employed to characterize both taxonomic and functional changes within the gut microbial community. We found that the progression of intestinal polyps in the control group altered the community functional profile remarkably despite small variation in the taxonomic diversity. In comparison, the consumption of LGG helped maintain the overall functional potential and taxonomic profile in the resident microbes, thereby leading to a 25% decrease of total polyp counts. Furthermore, we found that LGG enriched those microbes or microbial activities related to short-chain fatty acid production (e.g. Roseburia and Coprococcus), as well as suppressed the ones that can lead to inflammation (e.g. Bilophila wadsworthia). CONCLUSIONS: Our study using shotgun metagenomics highlights how single probiotic LGG may exert its beneficial effects and decrease polyp formation in mice by maintaining gut microbial functionality. SIGNIFICANCE AND IMPACT OF THE STUDY: This probiotic intervention targeting microbiota may be used in conjugation with other dietary supplements or drugs as part of prevention strategies for early-stage colon cancer, after further clinical validations in human.

Chemoprevention of polyp recurrence with curcumin followed by silibinin in a case of multiple colorectal adenomas.

Chemoprevention is a practical approach to reduce the risk of various cancers including colorectal cancer (CRC). The goal is to reduce the incidence of pre-neoplastic adenomatous polyps and prevent its progression to CRC. Curcumin and silibinin prevent intestinal polyp formation in mice. Curcumin sensitizes silymarin to exert synergistic anticancer activity in colon cancer cells. Patients presenting with multiple colorectal adenomatous polyps (MCRA) have a high lifetime risk for CRC. We present a 57-year-old man with MCRA, without deleterious germline APC or MYH mutations. Our patient had 54 polyps in the first colonoscopy, most of 3 to 8 mm and one of 20 mm with high grade dysplasia / adenocarcinoma. Four subsequent colonoscopies showed continuous development of adenomatous polyps treated by polypectomy for the most part and some with heat. After the treatment with curcumin for 3 months and a half followed by silibinin for 9 months, we find many less polyps than in the previous colonoscopies, going from the finding of 40 adenomas of 3-6 mm in the pre-treatment colonoscopy to 3 polyps after treatment.

Olive oil and omega-3 polyunsaturated fatty acids suppress intestinal polyp growth by modulating the apoptotic process in ApcMin/+ mice.

The promotion and progression of carcinogenesis are susceptible to nutritional interventions aimed at counteracting cancer development. Lipid metabolism is essential in the onset and progression of tumors and for cancer cell survival. In this study, we tested the effects of diets enriched with natural compounds, such as olive oil and salmon oil, in mice that spontaneously develop intestinal polyps (Apc(Min/+) mice). For this purpose, we evaluated polyp number and volume, intestinal mucosa proliferation/apoptosis, estrogen receptors (ERs) expression, fatty acid synthase and 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase gene expression and enzymatic activity. Compared with the standard diet, the salmon oil-enriched diet, containing a high percentage of omega-3 polyunsaturated fatty acids, and, to a lesser extent, olive oil-enriched diet reduced polyp number and volume through a reduction of proliferation and a marked proapoptotic effect. These biological effects were mediated by an inhibition of fatty acid synthase and HMGCoA reductase gene expression and activity and an increase of ERß/ERα ratio. Our findings suggest that a proper dietary lifestyle could contribute to primary cancer prevention.

A role for the epidermal growth factor receptor signaling in development of intestinal serrated polyps in mice and humans.

BACKGROUND & AIMS: Epithelial cancers can be initiated by activating mutations in components of the mitogen-activated protein kinase signaling pathway such as v-raf murine sarcoma viral oncogene homolog B1 (BRAF), v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS), or epidermal growth factor receptor (EGFR). Human intestinal serrated polyps are a heterogeneous group of benign lesions, but some progress to colorectal cancer. Tumors that arise from these polyps frequently contain activating mutations in BRAF or KRAS, but little is known about the role of EGFR activation in their development. METHODS: Polyp samples were obtained from adults during screening colonoscopies at Mount Sinai Hospital in New York. We measured levels of EGFR protein and phosphorylation in human serrated polyps by immunohistochemical and immunoblot analyses. We generated transgenic mice that express the ligand for EGFR, Heparin-binding EGF-like growth factor (HB-EGF), in the intestine. RESULTS: EGFR and the extracellular-regulated kinases (ERK)1/2 were phosphorylated in serrated areas of human hyperplastic polyps (HPPs), sessile serrated adenomas, and traditional serrated adenomas. EGFR and ERK1/2 were phosphorylated in the absence of KRAS or BRAF activating mutations in a subset of HPP. Transgenic expression of the EGFR ligand HB-EGF in the intestines of mice promoted development of small cecal serrated polyps. Mice that expressed a combination of HB-EGF and US28 (a constitutively active, G-protein-coupled receptor that increases processing of HB-EGF from the membrane) rapidly developed large cecal serrated polyps. These polyps were similar to HPPs and had increased phosphorylation of EGFR and ERK1/2 within the serrated epithelium. Administration of pharmacologic inhibitors of EGFR or MAPK to these transgenic mice significantly reduced polyp development. CONCLUSIONS: Activation of EGFR signaling in the intestine of mice promotes development of serrated polyps. EGFR signaling also is activated in human HPPs, sessile serrated adenomas, and traditional serrated adenomas.

Chemopreventive effect of ERß-Selective agonist on intestinal tumorigenesis in Apc(Min/+) mice.

Epidemiological and experimental evidence suggests that estrogen replacement therapy reduces the risk of colon cancer in postmenopausal women. Estrogen receptor beta (ERß) is thought to be the principal mediator of the estrogen effect in the colon. Recent studies by our team suggested positive regulation of the transforming growth factor (TGF)ß pathway by estrogen in mice colonocytes. We therefore wanted to investigate the effects of ERß agonist treatment on intestinal tumorigenesis in Apc(Min/+) mice. Weaned Apc(Min/+) mice were injected subcutaneously three times a week for 12 wk with vehicle or ERß-selective agonist, diarylpropionitrile (DPN, 5 mg/kg). DPN administration resulted in a significant reduction in small intestinal polyp multiplicity in both Apc(Min/+) male and female mice. Furthermore, the mean diameter of small intestinal polyps was lower in DPN-treated than vehicle-treated males, along with lower BrdU incorporation indices in jejunal and colon epithelial cells of both sexes. DPN treatment also increased apoptosis in colon epithelium as measured by TUNEL assay and cleaved caspase 3 quantification. The effect of DPN on various components of the TGFß pathway was also studied in colonocytes. DPN treatment increased expression of TGFß1 and TGFß3 transcripts, levels of nuclear and phosphorylated Smad2 as well as p27 cell-cycle inhibitor, a TGFß pathway target gene. Our results demonstrate that DPN treatment reduces intestinal tumorigenesis in Apc(Min/+) mice. Furthermore, we suggest that positive regulation of the TGFß pathway by ERß activation could contribute to the protective role of estrogen in intestinal tumor development.

Quercetin's effects on intestinal polyp multiplicity and macrophage number in the Apc(Min/+) mouse.

Numerous in vitro studies argue for quercetin's chemopreventive potential in colon cancer; however, experimental studies in rodents are limited. Macrophages play a role in tumorigenesis, but the effects of quercetin on macrophage infiltration in colon cancer is unknown. We examined the effects of quercetin on intestinal polyp multiplicity and macrophage number in Apc(Min/+) mice. Apc(Min/+) mice were assigned to placebo or quercetin (n = 8/group) groups. Mice were given a placebo or quercetin (0.02%) diet from 4-20 wk of age, after which intestines were analyzed for polyp number and size in the small intestine (Sections 1-4) and colon (Section 5) and for macrophage number in the small intestine (Sections 1 and 3). Spleen weight was determined as a marker of systemic inflammation. Quercetin decreased total intestinal polyps by 67% (P < 0.05). Specifically, quercetin reduced intestinal polyps in categories >2 mm (69%) and 1-2 mm (79%; P < 0.05), and in Sections 2 (75%), 3 (80%), and 4 (79%; P < 0.05). Quercetin also decreased macrophage number in Sections 1 (57%) and 3 (81%), and spleen weight (P < 0.05). These data suggest that quercetin can reduce polyp number and size distribution in the Apc(Min/+) mouse and that these effects may be related to a reduction in macrophage infiltration.

Inhibition of the mTORC1 pathway suppresses intestinal polyp formation and reduces mortality in ApcDelta716 mice.

The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that regulates cell growth via mTOR complex 1 (mTORC1), whose activation has been implicated in many human cancers. However, mTORC1's status in gastrointestinal tumors has not been characterized thoroughly. We have found that the mTORC1 pathway is activated with increased expression of the mTOR protein in intestinal polyps of the Apc(Delta716) heterozygous mutant mouse, a model for human familial adenomatous polyposis. An 8-week treatment with RAD001 (everolimus) suppressed the mTORC1 activity in these polyps and inhibited proliferation of the adenoma cells as well as tumor angiogenesis, which significantly reduced not only the number of polyps but also their size. beta-Catenin knockdown in the colon cancer cell lines reduced the mTOR level and thereby inhibited the mTORC1 signaling. These results suggest that the Wnt signaling contributes to mTORC1 activation through the increased level of mTOR and that the activation plays important roles in the intestinal polyp formation and growth. Indeed, long-term RAD001 treatment significantly reduced mortality of the Apc(Delta716) mice. Thus, we propose that the mTOR inhibitors may be efficacious for therapy and prevention of colonic adenomas and cancers with Wnt signaling activation.

Eicosapentaenoic acid reduces rectal polyp number and size in familial adenomatous polyposis.

OBJECTIVE: The omega-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA) has anticolorectal cancer activity in vitro and in preclinical models. The present study tested whether a novel, enteric-coated formulation of EPA, as the free fatty acid (EPA-FFA), has chemopreventative efficacy in patients with familial adenomatous polyposis (FAP), in a randomised, double-blind, placebo-controlled trial. METHODS: Patients undergoing endoscopic surveillance of their retained rectum postcolectomy were randomised to EPA-FFA (SLA Pharma) 2 g daily or placebo for 6 months. The number and size of polyps in an area of mucosa defined by a tattoo were determined before and after intervention. Global rectal polyp burden was scored (-1, 0, +1) by examination of video endoscopy records. Mucosal fatty acid content was measured by gas chromatography-mass spectrometry. RESULTS: 55 patients with FAP were evaluated by an intention-to-treat analysis (EPA-FFA 28, placebo 27). Treatment with EPA-FFA for 6 months was associated with a mean 22.4% (95% CI 5.1% to 39.6%) reduction in polyp number (p=0.012) and a 29.8% (3.6% to 56.1%) decrease in the sum of polyp diameters (p=0.027). Global polyp burden worsened over 6 months in the placebo group (-0.34) unlike the EPA-FFA group (+0.09, difference 0.42 (0.10-0.75), p=0.011). EPA-FFA treatment led to a mean 2.6-fold increase in mucosal EPA levels (p=0.018 compared with placebo). EPA-FFA was well tolerated with an incidence of adverse events similar to placebo. CONCLUSIONS: EPA-FFA has chemopreventative efficacy in FAP, to a degree similar to that previously observed with selective cyclo-oxygenase-2 inhibitors. EPA holds promise as a colorectal cancer chemoprevention agent with a favourable safety profile.

Sunitinib malate inhibits intestinal tumor development in male ApcMin/+ mice by down-regulating inflammation-related factors with suppressing ß-cateinin/c-Myc pathway and re-balancing Bcl-6 and Caspase-3.

Sunitinib is a tyrosine kinase inhibitor for many tumors. Inflammation is one of the most important factors in the development of intestinal tumors. Many inflammation-related factors are regulated by tyrosine kinase receptors. It is reasonable to hypothesize that sunitinib can regulate the development of intestinal tumors by regulating the expression and/or activity of inflammation-related factors. Here, ApcMin/+ male mouse model was used to investigate the effect and mechanism of sunitinib malate against intestinal cancer. Results show that compared to vehicle, after sunitinib malate treatment, overall survival of ApcMin/+ mice was lengthened up to 25 days, with a gain of body weight, reduction of spleen/body weight index, and RBC, WBC and HGC regulated to normal levels of wild type mice, and a number of polyps no less than 1 mm significantly reduced. Meanwhile, in the intestines, the nuclear ß-Catenin protein and c-Myc mRNA were both down-regulated, and Bcl-6 was significantly reduced with Caspase-3 up regulated. Furthermore, inflammation-related factors including IL-6, TNF-α, IL-1α, IL-1ß and IFN-γ were down-regulated at mRNA levels in the intestines. These results suggest that sunitinib malate can significantly improve the survival status and inhibit intestinal tumor development in male ApcMin/+ mice, through inhibiting inflammation-related factors, while suppressing ß-cateinin/c-Myc pathway and re-balancing protein levels of Bcl-6 and Caspase-3.

Aspirin, salicylates, and cancer.

Evidence from a wide range of sources suggests that individuals taking aspirin and related non-steroidal anti-inflammatory drugs have reduced risk of large bowel cancer. Work in animals supports cancer reduction with aspirin, but no long-term randomised clinical trials exist in human beings, and randomisation would be ethically unacceptable because vascular protection would have to be denied to a proportion of the participants. However, opportunistic trials of aspirin, designed to test vascular protection, provide some evidence of a reduction in cancer, but only after at least 10 years. We summarise evidence for the potential benefit of aspirin and natural salicylates in cancer prevention. Possible mechanisms of action and directions for further work are discussed, and implications for clinical practice are considered.

Natural Killer T-Cell Agonist α-Galactosylceramide and PD-1 Blockade Synergize to Reduce Tumor Development in a Preclinical Model of Colon Cancer.

Murine and human invariant natural killer T (iNKT) lymphocytes are activated by α-galactosylceramide (α-GalCer) presented on CD1d. α-GalCer was first described as a lipid that had strong anti-metastatic effects in a mouse melanoma model, and it has subsequently been shown to induce efficient iNKT cell dependent tumor immunity in several tumor models. We have shown that α-GalCer treatment leads to a weak reduction of polyp burden in the autochthonous ApcMin/+ mouse model for human colon cancer, however this treatment resulted in upregulation of the inhibitory receptor PD-1 on iNKT cells. While anti-PD-1 treatment can prevent immune-suppression in other cancer types, human colon cancer is generally resistant to this treatment. Here we have used the ApcMin/+ model to investigate whether a combined treatment with α-GalCer and PD-1 blockade results in improved effects on polyp development. We find that PD-1 expression was high on T cells in polyps and lamina propria (LP) of ApcMin/+ mice compared to polyp free Apc+/+ littermates. Anti-PD-1 treatment alone promoted Tbet expression in iNKT cells and CD4 T cells, but did not significantly reduce polyp numbers. However, the combined treatment with anti-PD-1 and α-GalCer had synergistic effects, resulting in highly significant reduction of polyp numbers in the small and large intestine. Addition of PD-1 blockade to α-GalCer treatment prevented loss of iNKT cells that were skewed towards a TH1-like iNKT1 phenotype specifically in polyps. It also resulted in TH1 skewing and increased granzyme B expression of CD4 T cells. Taken together this demonstrates that a combination of immune stimulation targeting iNKT cells and checkpoint blockade may be a promising approach to develop for improved tumor immunotherapy.

Traditional Processed Meat Products Re-designed Towards Inulin-rich Functional Foods Reduce Polyps in Two Colorectal Cancer Animal Models.

Inulin-rich foods exert a prebiotic effect, as this polysaccharide is able to enhance beneficial colon microbiota populations, giving rise to the in situ production of short-chain fatty acids (SCFAs) such as propionic and butyric acids. These SCFAs are potent preventive agents against colorectal cancer due to their histone deacetylases inhibitory properties, which induce apoptosis in tumor colonocytes. As colorectal cancer is the fourth most common neoplasia in Europe with 28.2 new cases per 100,000 inhabitants, a cost-effective preventive strategy has been tested in this work by redesigning common porcine meat products (chorizo sausages and cooked ham) consumed by a substantial proportion of the population towards potential colorectal cancer preventive functional foods. In order to test the preventive effect of these inulin-rich meat products against colorectal cancer, an animal model (Rattus norvegicus F344) was used, involving two doses of azoxymethane (10 mg/kg) and two treatments with dextran sodium sulfate (DSS) during a 20-week assay period. Control feed, control sausages, functional sausages (15.7% inulin), control cooked ham and functional cooked ham (10% inulin) were used to feed the corresponding animal cohorts. Then, the animals were sacrificed and their digestive tract tissues were analyzed. The results showed a statistically significant 49% reduction in the number of colon polyps in the functional meat products cohorts with respect to the control meat products animals, as well as an increase in the cecum weight (an indicator of a diet rich in prebiotic fiber), a 51.8% increase in colon propionate production, a 39.1% increase in colon butyrate concentrations, and a reduction in the number of hyperplastic Peyer's patches. Metagenomics studies also demonstrated colon microbiota differences, revealing a significant increase in Bacteroidetes populations in the functional meat products (mainly due to an increase in Bacteroidaceae and Prevotellaceae families, which include prominent propionate producers), together with a reduction in Firmicutes (especially due to lower Lachnospiraceae populations). However, functional meat products showed a remarkable increase in the anti-inflammatory and fiber-fermentative Blautia genus, which belongs to this Lachnospiraceae family. The functional meat products cohorts also presented a reduction in important pro-inflammatory bacterial populations, such as those of the genus Desulfovibrio and Bilophila. These results were corroborated in a genetic animal model of CRC (F344/NSlc-Apc1588/kyo) that produced similar results. Therefore, processed meat products can be redesigned towards functional prebiotic foods of interest as a cost-effective dietary strategy for preventing colorectal cancer in human populations.

Plasminogen activator inhibitor-1 (Pai-1) blockers suppress intestinal polyp formation in Min mice.

Obesity and hyperlipidemia are known to increase colorectal tumor risk. We noticed that Min mice, featuring a defect in the adenomatous polyposis coli (Apc) gene, develop intestinal polyps along with high serum triglyceride (TG) levels up to 10-fold those observed in wild-type mice. In these mice, messenger RNA (mRNA) expression of lipoprotein lipase, which catalyzes hydrolysis of TG, is downregulated. In the present study, we focused on adipocytokines, especially plasminogen activator inhibitor-1 (Pai-1), which is involved in hyperlipidemic status and may promote intestinal polyp formation in Min mice. Serum Pai-1 levels in the 15-week-old male Min mice were eight times higher than in wild-type mice and hepatic Pai-1 mRNA levels were 11-fold increased. In addition, Pai-1 immunostaining was strong in small intestinal epithelial cells of Min mice. Administration of a PAI-1 inhibitor, SK-216, at 25, 50 and 100 p.p.m. doses in the diet for 9 weeks reduced serum Pai-1 levels and hepatic Pai-1 mRNA levels of Min mice to the wild-type levels. Moreover, SK-216 at 50 and 100 p.p.m. significantly reduced total numbers of intestinal polyps to 64 and 56% of the untreated group value, respectively. Serum TG levels were also decreased by 43% at the dose of 100 p.p.m. Administration of 50 p.p.m. SK-116, another PAI-1 inhibitor, for 9 weeks similarly reduced serum Pai-1 levels and total numbers of intestinal polyps to 70% of the untreated group value. These results indicate that Pai-1 induction associated with hypertriglyceridemia may contribute to intestinal polyp formation with Apc deficiency, and PAI-1 could thus be a novel target for colorectal chemopreventive agents.

Metformin suppresses intestinal polyp growth in ApcMin/+ mice.

Metformin is a biguanide derivative that is widely used in the treatment of diabetes mellitus. One of the pharmacological targets of metformin is adenosine monophosphate-activated protein kinase (AMPK). We investigated the effect of metformin on the suppression of intestinal polyp formation in Apc(Min/+) mice. Administration of metformin (250 mg/kg) did not reduce the total number of intestinal polyp formations, but significantly reduced the number of intestinal polyp formations larger than 2 mm in diameter in Apc(Min/+) mice. To examine the indirect effect of metformin, the index of insulin resistance and serum lipid levels in Apc(Min/+) mice were assessed. These factors were not significantly attenuated by the treatment with metformin, indicating that the suppression of polyp growth is not due to the indirect drug action. The levels of tumor cell proliferation as determined by 5-bromodeoxyuridine and proliferating cell nuclear antigen immunohistochemical staining, and apoptosis, via transferase deoxytidyl uridine end labeling staining, in the polyps of metformin-treated mice were not significantly different in comparison to those of control mice. Gene expression of cyclin D1 and c-myc in intestinal polyps were also not significantly different between those two groups. In contrast, metformin activated AMPK in the intestinal polyps, resulting in the inhibition of the activation of mammalian target of rapamycin, which play important roles in the protein synthesis machinery. Metformin suppressed the polyp growth in Apc(Min/+) mice, suggesting that it may be a novel candidate as a chemopreventive agent for colorectal cancer.

Combination chemoprevention of intestinal carcinogenesis in a murine model of familial adenomatous polyposis.

Familial adenomatous polyposis (FAP) is an autosomal dominantly inherited syndrome in humans. The Apc(Min/+) mouse, which expresses a mutant homolog of the adenomatous polyposis coli gene, is a model of FAP in humans. Treatment with the nonsteroidal anti-inflammatory drugs (NSAIDS) sulindac or celecoxib can suppress polyp development in FAP patients, but responses are generally transient and incomplete. Combination chemoprevention with the ornithine decarboxylase inhibitor difluoromethylornithine (DFMO) and either celecoxib or sulindac was evaluated in the Apc(Min/+) mouse. Combinations of DFMO and either NSAID reduced intestinal tumor number by more than 80% (P < 0.0001) compared to untreated controls. In addition to the dramatic reduction in tumor number, the combination of DFMO and sulindac reduced the development of high-grade intestinal adenomas compared to sulindac alone (P = 0.003). The fraction of high-grade intestinal adenomas remaining after treatment was similar for the combination of DFMO and celecoxib and celecoxib alone. Only combinations of DFMO plus sulindac reduced total intestinal polyamine contents compared to untreated mice. These data support the rationale for treatment of FAP patients postcolectomy with DFMO combined with either celecoxib or sulindac but indicate that sulindac may be more effective than celecoxib in reducing intestinal polyamine contents and the incidence of high-grade intestinal adenomas when combined with DFMO.

[Screening of colorectal neoplasm]. / Screening des kolorektalen Karzinoms.

In Germany approximately 29,000 people died of colorectal carcinoma (CRC) in 2002; the risk of getting CRC is 4-6% in Germany, rising with age from the 50th year of life. About one third of all people over 50 years of age have polyps with the potential for malignant transformation in the colorectum, which is a sufficiently high prevalence rate to justify screening. In contrast to most other cancer diseases, in the case of CRC it is possible to prevent the cancer and not only to detect it at an early stage. Application of the test for occult blood in persons between their 45th and 80th years can reduce the mortality of CRC by 14%. We can assume that already regular sigmoidoscopies with consistent performance of polypectomy when needed could reduce the incidence of CRC by 50-70%. There is no doubt that coloscopy is the technique of choice for secondary prevention, as it unites the possibility of complete diagnosis and treatment with a justifiably low level of risk. The economic advantages of an avoidance strategy compared with the treatment of CRC, which is certainly expensive, have been documented. On the basis of all the data reported, in the case of CRC preventive strategies can be emphatically recommended.

[Screening and surveillance for hereditary polyposis and non-polyposis syndromes with capsule endoscopy]. / Hereditaer intestinalis polyposis- és nem polyposisos szindrómák követése és szurése kapszulás endoszkópiával.

The hereditary polyposis syndromes and non-polyposis colorectal carcinoma have been considered as scarcely occurring but inheritable dominant autosomal syndromes. The increasing risk of small bowel carcinoma and prevention of obstruction and intussusception have been making frequent and acute surgical interventions unavoidably led to the necessity of screening and surveillance the patients. Earlier the diagnosis of these symptoms was difficult to establish because traditional radiological methods have a low yield for small polyps. Furthermore, small bowel is only partially accessible with traditional endoscopic techniques such as upper endoscopy, colonoscopy and push-enteroscopy. The "wireless" capsule endoscopy has opened the way then for the non-invasive and painless test of the entire small intestine. - Test results have been cumulated to justify the efficiency and safety of capsule endoscopy concerning the syndromes above. This method can be applied safely even consequently to repeatedly performed surgical interventions by low risk of capsule retention. As the results compared of the diagnosed familial adenomatous polyposis and of Peutz-Jeghers syndrome reflect on capsule endoscopy, its diagnostic sensitiveness is stated as significantly higher than the Barium-contrast X-Ray and MR-enterography. Nevertheless, determination of size and location of polyps has become more problematic when evaluating the test results.