Chemoprevention Of Colon Cancer Research Articles

Chemoprevention of Colon Cancer by DFMO, Sulindac, and NO-Sulindac Administered Individually or in Combinations in F344 Rats.

Non-steroidal anti-inflammatory drugs (NSAIDs) are promising colorectal cancer (CRC) chemopreventive drugs; however, to overcome NSAIDs' associated side effects, there is a need to develop safer and efficacious approaches. The present study was designed to evaluate (i) the efficacy of nitric-oxide releasing (NO)-Sulindac as compared to Sulindac; (ii) whether NO-Sulindac is superior to Sulindac in enhancing low-dose difluoromethylornithine (DFMO)-induced chemopreventive efficacy, and (iii) assessing the key biomarkers associated with colon tumor inhibition by these combinations. In F344 rats, colonic tumors were induced by azoxymethane (AOM). At the adenoma stage (13 weeks post AOM), groups of rats were fed the experimental diets containing 0 ppm, 500 ppm DFMO, 150 ppm Sulindac, and 200 ppm NO-Sulindac, individually or in combinations, for 36 weeks. Colon tumors were evaluated histopathologically and assayed for expression levels of proliferative, apoptotic, and inflammatory markers. Results suggest that (except for NO-Sulindac alone), DFMO, Sulindac individually, and DFMO combined with Sulindac or NO-Sulindac significantly suppressed AOM-induced adenocarcinoma incidence and multiplicities. DFMO and Sulindac suppressed adenocarcinoma multiplicity by 63% (p < 0.0001) and 51% (p < 0.0011), respectively, whereas NO-Sulindac had a modest effect (22.8%, p = 0.09). Combinations of DFMO plus Sulindac or NO-Sulindac suppressed adenocarcinoma incidence (60%, p < 0.0001; 50% p < 0.0004), and multiplicity (81%, p < 0.0001; 62%, p < 0.0001). Rats that were fed the combination of DFMO plus Sulindac showed significant inhibition of tumor cell proliferation and induction of apoptosis. In addition, enhancement of p21, Bax, and caspases; downregulation of Ki-67, VEGF, and β-catenin; and modulation of iNOS, COX-2, and ODC activities in colonic tumors were observed. These observations show that a lower-dose of DFMO and Sulindac significantly enhanced CRC chemopreventive efficacy when compared to NO-Sulindac alone, and the combination of DFMO and NO-Sulindac was modestly efficacious as compared to DFMO alone.

A Non-Systemic Phosphodiesterase-5 Inhibitor Suppresses Colon Proliferation in Mice.

Phosphodiesterase-5 inhibitors (PDE5i) are under investigation for repurposing for colon cancer prevention. A drawback to conventional PDE5i are their side-effects and drug-drug interactions. We designed an analog of the prototypical PDE5i sildenafil by replacing the methyl group on the piperazine ring with malonic acid to reduce lipophilicity, and measured its entry into the circulation and effects on colon epithelium. This modification did not affect pharmacology as malonyl-sildenafil had a similar IC50 to sildenafil but exhibited an almost 20-fold reduced EC50 for increasing cellular cGMP. Using an LC-MS/MS approach, malonyl-sildenafil was negligible in mouse plasma after oral administration but was detected at high levels in the feces. No bioactive metabolites of malonyl-sildenafil were detected in the circulation by measuring interactions with isosorbide mononitrate. The treatment of mice with malonyl-sildenafil in the drinking water resulted in a suppression of proliferation in the colon epithelium that is consistent with results previously published for mice treated with PDE5i. A carboxylic-acid-containing analog of sildenafil prohibits the systemic delivery of the compound but maintains sufficient penetration into the colon epithelium to suppress proliferation. This highlights a novel approach to generating a first-in-class drug for colon cancer chemoprevention.

Santin (5,7-Dihydroxy-3,6,4'-Trimetoxy-Flavone) Enhances TRAIL-Mediated Apoptosis in Colon Cancer Cells.

TRAIL (Tumor necrosis factor-Related Apoptosis-Inducing Ligand) has the ability to selectively kill cancer cells without being toxic to normal cells. This endogenous ligand plays an important role in surveillance and anti-tumor immunity. However, numerous tumor cells are resistant to TRAIL-induced apoptosis. In this study, the apoptotic effect of santin in combination with TRAIL on colon cancer cells was examined. Flow cytometry was used to detect the apoptosis and expression of death receptors (TRAIL-R1/DR4 and TRAIL-R2/DR5). Mitochondrial membrane potential (ΔΨm) was evaluated by DePsipher staining with the use of fluorescence microscopy. We have shown for the first time that flavonoid santin synergizes with TRAIL to induce apoptosis in colon cancer cells. Santin induced TRAIL-mediated apoptosis through increased expression of death receptors TRAIL-R1 and TRAIL-R2 and augmented disruption of the mitochondrial membrane in SW480 and SW620 cancer cells. The obtained data may indicate the potential role of santin in colon cancer chemoprevention through the enhancement of TRAIL-mediated apoptosis.

Abstract 1417: A non-systemic phosphodiesterase-5 inhibitor for colon cancer prevention

Abstract Phosphodiesterase 5 inhibitors (PDE5i) are under investigation for potential repurposing as an intervention for colon cancer prevention. A drawback to conventional drugs in this class are drug-drug interactions and side-effects and that would be poorly tolerated when taken on a chronic basis for prevention. To address this issue we designed an analog of the prototypical PDE5i sildenafil by replacing the methyl group on the piperazine ring with malonic acid to reduce lipophilicity. This modification did not affect pharmacology as malonyl-sildenafil had an IC50 of 1.8 nM, but exhibited almost 100-fold reduced cell entry compared to sildenafil. Using an LC-MS/MS approach, malonyl-sildenafil was undetectable in mouse plasma 1 hour after gavage, even at a dose up to 36 mg/kg, but was readily detected in the feces collected 2-4 hours after administration. This contrasted with sildenafil that was detected in the plasma, but not in the feces. While sildenafil exhibited the established Cmax at 1-2 hr, malonyl sildenafil was not detected in the plasma up to 24 hr after an oral dose of 9 mg/kg, but continued to be shed at high levels in the feces for up to 8 hrs. Treatment of mice with malonyl-sildenafil in the drinking water for 8 days was well-tolerated, and resulted in a suppression of proliferation in the colon epithelium that is consistent with results published previously for mice treated with PDE5i. Taken together, the results demonstrate that a carboxylic acid-containing analog of sildenafil prohibits systemic delivery but maintains sufficient penetration into the colon epithelium to suppress proliferation. This highlights a novel approach to generate a first in class drug for colon cancer chemoprevention. Citation Format: Bianca N. Islam, Avelina Lee, Iryna Lebedyeva, Darren D. Browning. A non-systemic phosphodiesterase-5 inhibitor for colon cancer prevention [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1417.

Effects of dihydroartemisinin, a metabolite of artemisinin, on colon cancer chemoprevention and adaptive immune regulation.

Artemisinin (ART) is an anti-malaria natural compound with a moderate anticancer action. As a metabolite of ART, dihydroartemisinin (DHA) may have stronger anti-colorectal cancer (CRC) bioactivities. However, the effects of DHA and ART on CRC chemoprevention, including adaptive immune regulation, have not been systematically evaluated and compared. Coupled with a newly-established HPLC analytical method, enteric microbiome biotransformation was conducted to identify if the DHA is a gut microbial metabolite of ART. The anti-CRC potential of these compounds was compared using two different human CRC cell lines for cell cycle arrest, apoptotic induction, and anti-inflammation activities. Naive CD4+T cells were also obtained for testing the compounds on the differentiation of Treg, Th1 and Th17. Using compound extraction and analytical methods, we observed for the first time that ART completely converted into its metabolites by gut microbiome within 24h, but no DHA was detected. Although ART did not obviously influence cancer cell growth in the concentration tested, DHA very significantly inhibited the cancer cell growth at relatively low concentrations. DHA included G2/M cell cycle arrest via upregulation of cyclin A and apoptosis. Both ART and DHA downregulated the pro-inflammatory cytokine expression. The DHA significantly promoted Treg cell proliferation, while both ART and DHA inhibited Th1 and Th17 cell differentiation. As a metabolite of ART, DHA possessed stronger anti-CRC activities. The DHA significantly inhibited cell growth via cell cycle arrest, apoptosis induction and anti-inflammation actions. The adaptive immune regulation is a related mechanism of actions for the observed effects.

COX-2 Inhibitors Decrease Expression of PD-L1 in Colon Tumors and Increase the Influx of Type I Tumor-infiltrating Lymphocytes.

Nonsteroidal anti-inflammatories (NSAID) are an essential component of any combination chemoprevention of colon cancer. We show NSAID treatment reduces PD-L1 expression on intestinal tumor cells. NSAID regulation of PD-L1 is dependent on COX-2 expression. These data underscore an important immunologic mechanism of action for NSAID in colon cancer prevention. See related Spotlight, p. 209.

Suppression of C-C chemokine receptor 1 is a key regulation for colon cancer chemoprevention in AOM/DSS mice by fucoxanthin

Fucoxanthin (Fx) has shown potential cancer chemopreventive functions in a carcinogenic murine azoxymethane/dextran sodium sulfate (AOM/DSS) model. However, the molecular mechanisms based on transcriptome profiles in vivo remain poorly understood. We investigated Fx-dependent alterations of the transcriptome with cancer-associated proteins in colorectal mucosal tissue obtained from AOM/DSS mice with or without Fx treatment. Fx administration (50 mg/kg body weight for 14 weeks) significantly prevented the onset of colorectal adenocarcinoma in AOM/DSS mice. A transcriptome analysis revealed that 11 signals, including adhesion, cell cycle, chemokine receptor, interleukin, MAPK, PI3K/AKT, p53, RAS, STAT, TGF-β, and Wnt were remarkably altered by Fx administration. In particular, chemokine (C-C motif) receptor 1 (Ccr1), which is contained in a gene set related to cytokine-cytokine receptor interactions, was the only significantly down-regulated gene after Fx administration for both 7 and 14 weeks. CCR1, AKT, Cyclin D1, and Smad2 were found to play central roles in the 11 signals shown above. Fx administration significantly down-regulated CCR1 (0.3- and 0.5-fold in mucosal crypts and lamina propria, respectively), pAKT(Ser473) (0.2-fold in mucosal crypts), Cyclin D1 (0.4-fold in mucosal crypts), and pSmad2(Ser465/467) (0.7-fold in mucosal crypts) compared with proteins in these tissues of control mice after Fx administration for 14 weeks. Our findings suggested that Fx exerts a chemopreventive effect in AOM/DSS mice through attenuation of CCR1 expression along with 11 cancer-associated signals.

Double w/o/w self-nano emulsifying drug delivery system of imatinib mesylate for colon cancer treatment

The aim of the research was to prepare & evaluate double w/o/w self-nano emulsifying drug delivery system (SNEDDS) of imatinib mesylate (IMT) and to investigates its anticancer activity against MDST8 human colon carcinoma cell lines. The self-nano emulsifying drug delivery system was prepared by the aqueous phase titration method. After the necessary screening, the optimized formulation (F-SEN-5) was characterized for surface morphology, using high-resolution transmission electron microscopy (Philips CM 120 BioTwin, U.S.A.). Furthermore, average droplet diameter (Δdm), polydispersity index (PDI), refractive index (Ri), viscosity (η), percentage transmittance (%T), percentage drug content (% DC), In-vitro drug release studies were measured for all the formulations; The optimized F-SEN-5 shows R2 = 0.9987, n (0.5 < n < 1.0) = 0.732, indicating the Korsmeyer-Peppas drug release model and anomalous transport. The higher drug release profile (99.42 ± 5.23%) at 60 min, higher transmittance (%) (98.56 ± 0.56%), low viscosity (28.67 ± 3.67cps), low PDI (0.078 ± 0.05), low average droplet diameter (47.56 ± 5.78 nm) at 2:1 Smix ratio. The in-vitro cytotoxicity (%) and IC50 value of F-SEN-5 while treating MDST8 human colon carcinoma cell lines were found to be 93.71 ± 8.11% and 15 µM. The formulation provides an additional 20% more efficiency than the free IMT drug. Overall, these findings suggested that double w/o/w nanoemulsions can be successfully used for SNEDDS of IMT for chemoprevention of colon cancer.

Monofloral Honeys as a Potential Source of Natural Antioxidants, Minerals and Medicine.

Background: vegetative diversity is based on different climate and geographical origins. In terms of beekeeping, herbal diversity is strongly correlated to the production of a wide variety of honey. Therefore, based on the existing plant diversity in each country, multiple honey varieties are produced with different health characteristics. While beekeeping potential and consumption preferences are reflected in products’ variety, this leads to an increase in the region’s economy and extensive export. In the last years, monofloral honey has gained interest from consumers and especially in the medicinal field due to the presence of phytochemicals which are directly linked to health benefits, wound healing, antioxidant, anticancer and anti-inflammatory activities. Scope and approach: this review aims to highlight the physicochemical properties, mineral profiles and antioxidant activities of selected monofloral honeys based on their botanical and geographical origin. Moreover, this review focuses on the intercorrelation between monofloral honey’s antioxidant compounds and in vitro and in vivo activities, focusing on the apoptosis and cell proliferation inhibition in various cell lines, with a final usage of honey as a potential therapeutic product in the fight towards reducing tumor growth. Key findings and conclusions: multiple studies have demonstrated that monofloral honeys have different physicochemical structures and bioactive compounds. Useful chemical markers to distinguish between monofloral honeys were evidenced, such as: 2-methoxybenzoic acid and trimethoxybenzoic acid are distinctive to Manuka honey while 4-methoxyphenylacetic acid is characteristic to Kanuka honey. Furthermore, resveratrol, epigallocatechin and pinostrobin are markers distinct to Sage honey, whereas carvacrol and thymol are found in Ziziphus honey. Due to their polyphenolic profile, monofloral honeys have significant antioxidant activity, as well as antidiabetic, antimicrobial and anticancer activities. It was demonstrated that Pine honey decreased the MDA and TBARS levels in liver, kidney, heart and brain tissues, whereas Malicia honey reduced the low-density lipoprotein level. Consumption of Clover, Acacia and Gelam honeys reduced the weight and adiposity, as well as trygliceride levels. Furthermore, the antiproliferative effect of chrysin, a natural flavone in Acacia honey, was demonstrated in human (A375) and murine (B16-F1) melanoma cell lines, whereas caffeic acid, a phenolic compound found in Kelulut honey, proves to be significant candidate in the chemoprevention of colon cancer. Based on these features, the use of hiney in the medicinal field (apitherapy), and the widespread usage of natural product consumption, is gaining interest by each year.

Piperlongumine targets NF-κB and its downstream signaling pathways to suppress tumor growth and metastatic potential in experimental colon cancer.

NF-κB is the principle transcription factor and plays the central role in orchestrating chronic inflammation by regulating levels of cytokines, chemokines and growth factors. Piperlongumine (PL), a major alkaloid in the fruit of Piper longum Linn. has gained worldwide attention for its anticancer properties, however, its mechanism of action in the chemoprevention of colon cancer has not been investigated yet. Therefore, the present study was designed to elucidate the underlying molecular mechanism of PL in preventing DMH/DSS induced experimental colon cancer in mice. In the current study well established DMH/DSS induced experimental colon cancer mouse model was used to demonstrate the chemopreventive potential of PL. The expression of NF-κB and its downstream target proteins was evaluated mainly through western blotting. In addition, CAM assay, immunohistochemical staining and gelatin zymography was used to show anti-angiogenic and anti-invasive potential of PL. Additionally, important tumor biomarkers such as TSA, LASA, LDH and IL-6 levels were also estimated. The results of current study showed that PL was capable to inhibit NF-κB activation as well as its nuclear translocation. PL administration to DMH/DSS treated mice also inhibited the NF-κB downstream signaling cascades such as including COX-2 pathway, JAK/STAT pathway, β-catenin, Notch signaling pathway, angiogenesis and epithelial to mesenchymal transition pathway. The findings of the present study have claimed PL as promising chemopreventive agent for colon cancer with pleiotropic action. The current study emphasizes that regular consumption of PL can be an effective approach in the prevention of colon cancer in humans.

Enhancement of chemopreventive properties of young green barley and chlorella extracts used together against colon cancer cells.

Young green barley and chlorella are listed as a panacea for a whole range of disorders, including diabetes, cardiovascular disease, infections, and hypercholesterolaemia. The first reports have appeared presenting the anticancer properties of these products. The present study is an attempt to extend this knowledge with particular emphasis on the possibility of using young green barley, chlorella, and their combination in colon cancer chemoprevention. Extracts of young green barley (YB) and chlorella (CH), as well as their combination MIX (YB+CH; 1:1), were examined. The influence of the extracts on viability and proliferation of human colon epithelial CCD841 CoN cells was analyzed by LDH and MTT assays. Anticancer properties of extracts were screened on human colon adenocarcinoma cell line HT-29 by MTT and BrdU assays. Changes in cells morphology in response to extracts were investigated after May-Grünwald-Giemsa staining. Extracts used together or separately did not affect the viability and proliferation of CCD841 CoN cells. Simultaneously, YB, CH and MIX inhibited proliferation of HT-29 cells in a dose-dependent manner. Furthermore changes in the morphology of HT-29 cells treated with YB, CH and MIX suggested necrosis induction. Performed studies also revealed that MIX induced a stronger antiproliferative effect than their individual ingredients; however, the discovered enhancement of anticancer properties was weaker than the sum of the effects of YB and CH creating MIX. The study demonstrates great chemopreventive properties of young green barley and chlorella water extracts and their combination in in vitro model of colon cancer. The anticancer properties of the investigated extracts were significantly enhanced after combining, without an increase of their toxicity against normal cells.

Targeting the aryl hydrocarbon receptor in stem cells to improve the use of food as medicine.

Intestinal stem cells, the most rapidly proliferating adult stem cells, are exquisitely sensitive to extrinsic dietary factors. Uncontrolled regulation of intestinal stem cells is closely linked to colon tumorigenesis. This review focuses on how dietary and microbial derived cues regulate intestinal stem cell functionality and colon tumorigenesis in mouse models by targeting the aryl hydrocarbon receptor (AhR). AhR, a ligand activated transcription factor, can integrate environmental, dietary and microbial cues to modulate intestinal stem cell proliferation, differentiation and their microenvironment, affecting colon cancer risk. Modulation of AhR activity is associated with many chronic diseases, including inflammatory bowel diseases where AhR expression is protective. AhR signaling controls the maintenance and differentiation of intestinal stem cells, influences local niche factors, and plays a protective role in colon tumorigenesis. Mounting evidence suggests that extrinsic nutritional/dietary cues which modulate AhR signaling may be a promising approach to colon cancer chemoprevention.

Abstract 4755: Chemoprevention and pharmacokinetics study using Gasdermin D knock out induced colon cancer model mouse treated with FAS inhibitors

Abstract (Introduction) It is well known that cancer cell harness different metabolic pathway from normal cells more efficiently. Recent studies indicate disorder of lipid metabolism has happen even in the benign cell, and that cause to be malignancy. Our research group focus attention on irregular accumulation of fatty acid in cancer cells. This time, we analysis several studies using Gasdermin D knock out induced colon cancer model mouse treated with FAS inhibitors. 1) metabolism analysis for mouse colon cancer. 2) Colon cancer treatment and chemoprevention by FAS inhibitor 3)Pharmacokinetics status of FAS inhibitor (colon cancer model mouse) Gasdermin D (GSDM D), pylotosis key factor, knockout mouse treat with AOM and DSS. 3month after all mouse has several big tumors (patent in Japan 2016-69775) (Result) 1) There are Many famous long chain fatty acids in cancer tissue. And also Very Long Chain Fatty Acid (:VLCFA) can detected by this analysis. 2) C75 and Kampo (include Berberine) can decrease tumor number and size. And they has chemoprevention effects, too. 3) Almost 40% FAS activity can reduce by everyday FAS inhibitor treatment. (Conclusion) AS metabolic disorders seem to induce colon cancer carcinogenesis, this target therapy can work for that prevention and treatment. Citation Format: Hajime Orita, Hyeoncheol Lee, Toshiyuki Kobayashi, Tetsu Fukunaga. Chemoprevention and pharmacokinetics study using Gasdermin D knock out induced colon cancer model mouse treated with FAS inhibitors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4755.

Abstract 2978: Cyclic GMP-independent inhibition of colon cancer cell growth by phosphodiesterase inhibitors

Abstract There is growing interest in the potential use of phosphodiesterase (PDE) inhibitors for colon cancer chemoprevention, but the tumor suppressive mechanism is not understood. The present study has tested the idea that PDE inhibitors can suppress growth and promote apoptosis of colon cancer cell lines by increasing cGMP and activating cGMP-dependent protein kinase (PKG). Treatment of LS174T, Caco2, and HCT116 colon cancer cells with membrane permeable 8Br-cGMP had no effect on cell proliferation or viability. Endogenous PKG was undetectable in any of these cells using phosphorylation of the PKG substrate vasodilator-stimulated phosphoprotein (VASP) as a readout. Ectopic expression of PKG2 conferred modest inhibition of proliferation by cGMP treatment (15-25% over 3 days), but did not affect cell viability. The lack of effect of cGMP on colon cancer proliferation is incongruous with many reported effects of PDE inhibitors. To understand the reason for the discrepant observations, colon cancer cells were treated with sildenafil, PF-0447943, and TAK-063 that are specific inhibitors of the cGMP-targeting PDE5, 9, 10a (respectively). At clinically unachievable concentrations exceeding 10μM, all of these drugs reduced proliferation to various degrees in the different cell lines. TAK-063 was the most effective, and the only one that reduced cell viability. Notably, growth-inhibition by the PDE inhibitors was independent of PKG expression, and surprisingly, none of them increased cGMP levels. The inability of the PDE inhibitors to increase cGMP was due to the lack of endogenous cGMP generation, because treatment with the guanylyl-cyclase C agonist linaclotide conferred a robust cGMP response to a physiological dose of sildenafil (1µM). The growth inhibitor effects of high, non-physiological levels of PDE inhibitors is likely due to off-target effects, but apart from a transient inhibition of the ERK pathway, no common mechanism was identified. Taken together, these results refute the idea that cGMP elevating agents prevent colon carcinogenesis by inhibiting cancer cell growth, and support the inhibition of tumor initiation as a more likely mechanism. Citation Format: Bianca N. Islam, Yali Hou, Namratha Mylarapu, Kaylin A. Browning, Kenneth J. Vega, Darren D. Browning. Cyclic GMP-independent inhibition of colon cancer cell growth by phosphodiesterase inhibitors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2978.

Role of Using Nonsteroidal Anti-Inflammatory Drugs in Chemoprevention of Colon Cancer in Patients With Inflammatory Bowel Disease.

The process of inflammation occurs due to inflammatory mediators, including prostaglandins, cytokines, and tumor necrosis factor (TNF). All these mediators activate the process of tumorigenesis and dysplasia, leading to colitis-associated cancer. Several drugs used to decrease these mediators will help in the treatment of acute attacks and also help in prolonged remissions of the disease by using nonsteroidal anti-inflammatory drugs (NSAIDs), steroids, and biological factors. Reducing these inflammatory mediators also have a role in chemoprevention and prevent progression to colorectal carcinoma. The most researched drugs in this process of chemoprevention are NSAIDs as it has both cyclooxygenase-2 (COX-2) inhibitory and non-inhibitory effects. These drugs should be taken for a long time and in large doses to reach this effect, which puts the patient at risk for various side effects. Researchers will need to do more research in the future to find the lowest effective dose that can reach the chemopreventive effect. We used database Pubmed as the main source for data search and extracted articles exploring the relationship between NSAIDs and their role in chemoprevention of colorectal carcinoma in inflammatory bowel disease (IBD) patients. We chose 23 studies which included seven review articles. We found that inflammatory mediators have a key role in colitis-associated cancer.

Chemoprevention of Colon Cancer by Dietary Intake of Sulforaphane

BackgroundSulforaphane (SFN), a phytochemical compound, which belongs to isothiocyanates family found in abundance in broccoli sprouts, potently induces a variety of antioxidant enzymes via NF‐E2‐related factor 2‐Kelch‐like ECH‐associated protein 1‐mediated pathway, thereby protects cells from injury induced by various kinds of oxidative stresses. We have previously shown that SFN protects gastric mucosa from oxidative injury induced by H. pyloriinfection. SFN also down‐regulates histone deacetylase (HDAC) activity, thereby induces apoptosis and inhibits proliferation of tumor cells in variety of tissues. On the other hand, colon cancer has been increasing in Japan. Since numerous epidemiological studies have shown that colon cancer is inversely associated with intake of anti‐oxidant vegetables, we examined if daily intake of SFN prevents colon tumorigenesis in mice, and in human subjects.Methods1. Effects of SFN on Colonic tumorigenesis in Mice Treated with Chemical Carcinogen: Effects of SFN on colonic tumorigenesis were examined in the ICR male mice, pretreated with a chemical carcinogen, azoxymethane (AOM) (15 mg/kg). The mice treated with AOM for 3 or 6 times were fed for 8 or 24 weeks with or without sulforaphane glucosinolates (SGS: 2,200 ppm/kg/day), which is a precursor of SFN. Effects of SGS treatment on formation of the microscopic aberrant crypt foci (ACF), and the macroscopic tumors in colonic mucosa were evaluated. 2. Effects of SFN on formation of Colonic ACF in patients with colonic adenoma: Effects of intake of raw broccoli sprouts (BS), 50 g/day, which contains 220 mg SGS every other day, for 6 months on changes in the number of ACF in rectal mucosa was examined by colonoscopy in patients with colonic adenoma. 3. Effects of SFN on intestinal microbiota in human subjects: Effects of dietary intake of raw BS, 20 g/day, which contains 88 mg SGS every other day, for 2 weeks on intestinal microbiota in healthy volunteers was assessed by measuring composition of stool bacteria, using a method of terminal restriction fragment length polymorphism flora analysis. In human studies, alfalfa sprouts, which contains no SFN was used as a placebo control.Results1. Daily administration of SGS suppressed formation of microscopic ACF and macroscopic colonic tumors in the AOM‐pretreated mice in vivo. 2. Intake of BS for 6 months tended to decrease the number of colonic ACF in patients with colonic adenoma. 3. Intake of BS for 2 weeks increased percentages of Bifidobacterium and Clostridium XVIa, which has been shown to enhance protection of colonic mucosa by increasing butyrate production in colonic lumen.Conclusions1. Daily intake of SFN affords chemoprotection against colonic tumors in the mice treated with a chemical carcinogen. 2. The present study further suggests that, in addition to previously reported mechanisms, changes in the intestinal microbiota by SFN intake may also play a role in chemoprevention against colon cancer. Further studies are required to prove this possibility.Support or Funding InformationThis study was supported in part by Murakami Farm Inc., Japan.

Schizandrin A exhibits potent anticancer activity in colorectal cancer cells by inhibiting heat shock factor 1.

Heat shock factor 1 (HSF1) is a powerful multifaceted oncogenic modifier that plays a role in maintaining the protein balance of cancer cells under various stresses. In recent studies, there have been reports of increased expression of HSF1 in colorectal cancer (CRC) cells, and the depletion of the HSF1 gene knockdown has inhibited colon cancer growth both in vivo and in vitro. Therefore, HSF1 is a promising target for colon cancer treatment and chemoprevention. In the present study, we found that Schizandrin A (Sch A) significantly inhibited the growth of CRC cell lines by inducing cell cycle arrest, apoptosis and death. Through HSE luciferase reporter assay and quantitative PCR (qPCR), we identified Sch A as a novel HSF1 inhibitor. In addition, Sch A could effectively inhibit the induction of HSF1 target proteins such as heat-shock protein (HSP) 70 (HSP70) and HSP27, whether in heat shock or normal temperature culture. In the Surface Plasmon Resonance (SPR) experiment, Sch A showed moderate affinity with HSF1, further confirming that Sch A might be a direct HSF1 inhibitor. The molecular docking and molecular dynamic simulation results of HSF1/Sch A suggested that Sch A formed key hydrogen bond and hydrophobic interactions with HSF1, which may contribute to its potent HSF1 inhibition. These findings provide clues for the design of novel HSF1 inhibitors and drug candidates for colon cancer treatment.

The Effect of Aqueous Extract of Ocimum gratissium (Linn) on 1, 2 - Dimethyl Hydrazine induced Colon Cancer in Male Wistar Rats

Background Colon cancer is one of the leading causes of cancer death world-wide. There is a steady increase in incidence over the past four decades in developing countries. This has been partly attributed to increasingly low intake of vegetables among other causes. Aims Therefore this study aims to evaluate the protective effect of aqueous extract of Ocimumgratissimum (OG) leaves (a staple vegetable) on experimental model of colon carcinogenesis induced with 1, 2 Dimethylhydrazine (DMH). This is compared with celecoxib (a cyclooxygenase-2 inhibitor) which is used in the chemoprevention of colon cancer. Methods Sixty adult male Wistar rats were randomly divided into six groups: A to F, n=10. Group A was the normal control, Group B was given only DMH weekly for 16 weeks,Groups C, D and E were given graded doses of OG for two weeks prior to cancer induction by DMH. After which both OG and DMH were given for 16weeks. Group F received celecoxib daily for two weeks prior to cancer induction. Colonic wall was analysed grossly, histologically and biochemically. The induced lesions were staged investigated and staged using Duke’s Staging method. Results The result showed tumour incidence in groups B and C while no evidence of primary colonic tumour was observed in groups A, D, E and F. There was a dose dependent increase in the goblet cell count in the groups treated with OG with group E being statistically higher than group F. There was a significant reduction in collagen staining intensity (F = 129.74, p &lt; 0.0001) for the colonic wall in group B when compared to other groups. There was a decreased nucleo-cytoplasmic ratio in groups C, D, E and F when compared to group B. There was a significant increase in the concentration of nitric oxide and prostaglandin E2in group B when compared to other groups D, E and F. Conclusion In conclusion, this research showed a protective effect of Ocimumgratissimum leaves on 1, 2-dimethylhydrazine-induced colon cancer which further corroborated its ethno-medicinal use.

Djulis (Chenopodium Formosanum) Prevents Colon Carcinogenesis via Regulating Antioxidative and Apoptotic Pathways in Rats

Djulis is a cereal crop rich in polyphenols and dietary fiber that may have nutraceutical activity to prevent colon cancer. This study was designed to examine the preventive effect of djulis on colon carcinogenesis in rats treated with 1,2-dimethylhydrazine (DMH). Rats were fed different AIN-93G-based diets: groups N and DMH were fed AIN-93G diet and groups LD, MD, and HD were fed AIN-93G diet containing 5, 10, and 20% djulis, respectively. All rats except for group N were injected with DMH to induce colon carcinogenesis. After 10 weeks, rats were sacrificed and colon and liver tissues were collected for analysis. The results showed that djulis-treated rats had significantly lower numbers of colonic preneoplastic lesions, aberrant crypt foci (ACF), sialomucin-producing (SIM)-ACF, and mucin-depleted foci. Djulis treatment increased superoxide dismutase and catalase activities in colon and liver. Djulis also reduced p53, Bcl-2, and proliferating cell nuclear antigen expressions and increased Bax and caspase-9 expressions. Besides, phenolic compounds and flavonoids were found rich in djulis. These results demonstrate the chemopreventive effect of djulis on carcinogen-induced colon carcinogenesis via regulating antioxidative and apoptotic pathways in rats. Djulis may have the potential to be developed as a valuable cereal product for chemoprevention of colon cancer.

Sulforaphane-induced epigenetic regulation of Nrf2 expression by DNA methyltransferase in human Caco-2 cells.

The present study aimed to investigate the mechanism underlying sulforaphane-mediated epigenetic regulation of nuclear factor-erythroid derived 2-like 2 (Nrf2) expression in human colon cancer. Proteins were extracted from normal Caco-2 cells using sulforaphane and 5-aza-2'-deoxycytidine (5-Aza) combined with trichostatin A (TSA). The mRNA and protein expression levels and activity of DNA methyltransferase 1 (DNMT1) were determined. Methylation-specific polymerase chain reaction and bisulfite genomic sequencing were also used to measure the methylation levels of CpG sites in the Nrf2 promoter region. Nrf2 expression was measured using reverse transcription-quantitative PCR and western blot analysis. The results demonstrated that sulforaphane did not affect DNMT1 mRNA expression levels. DNMT1 protein expression was inhibited by sulforaphane and 5-Aza co-treatment with TSA. Nrf2 promoter methylation decreased significantly in the sulforaphane group compared with the control group. Nrf2 promoter methylation level in the 5-Aza+TSA group was the lowest among all groups. Nrf2 mRNA levels exhibited significant differences between the sulforaphane-treated and control groups, as well as between the 5-Aza+TSA and control groups, and the sulforaphane-treated and 5-Aza+TSA groups. Nrf2 protein expression was also inhibited by sulforaphane, as well as 5-Aza co-treatment with TSA. The results revealed that sulforaphane may promote demethylation of the Nrf2 promoter region to increase activation of Nrf2, which induces chemoprevention of colon cancer.