Early Colon Carcinogenesis Research Articles

Characterization of Extractable and Non-Extractable Phenols and Betalains in Berrycactus (Myrtillocactus geometrizans) and Its Chemoprotective Effect in Early Stage of Colon Cancer In Vivo.

This research identified the bioactive compounds and antioxidant capacity of the extractable (EP) and non-extractable (NEP) polyphenol fractions of berrycactus (BC). Additionally, the effects of BC and its residue (BCR) on preventing AOM/DSS-induced early colon carcinogenesis were evaluated in vivo. Male Sprague Dawley rats were randomly assigned to six groups (n = 12/group): healthy control (C), AOM/DSS, BC, BCR, BC+AOM/DSS, and BCR+AOM/DSS. NEP was obtained through acid hydrolysis using H2SO4 and HCl (1 M or 4 M). The HCl-NEP fraction exhibited the highest total phenolic and flavonoid content, while condensed tannins were more abundant in the H2SO4-NEP fraction. A total of 33 polyphenols were identified by UPLC-QTOF-MSE in both EP and NEP, some of which were novel to BC. Both NEP hydrolysates demonstrated significant total antioxidant capacity (TEAC), with HCl-NEP exhibiting the highest ORAC values. The BC+AOM/DSS and BCR+AOM/DSS groups exhibited fewer aberrant crypt foci (p < 0.05), reduced colonic epithelial injury, and presented lower fecal β-glucuronidase activity, when compared to AOM/DSS group. No differences in butyric acid concentrations were observed between groups. This study presents novel bioactive compounds in EP and NEP from BC that contribute to chemopreventive effects in early colon carcinogenesis, while reducing fecal β-glucuronidase activity and preserving colonic mucosal integrity.

The Interplay among Wnt/β-catenin Family Members in Colorectal Adenomas and Surrounding Tissues.

The colorectal adenoma undergoes neoplastic progression via the normal epithelium-adenoma-adenocarcinoma sequence as reported in the Vogelgram. The hazard of developing a tumor is deeply associated with the number and size of adenomas and their subtype. Adenomatous polyps are histologically categorized as follows: approximately 80-90% are tubular, 5-15% are villous, and 5-10% are tubular/villous. Given the higher risk of a malignant transformation observed in tubular/villous adenomas, patients diagnosed with adenomatous polyposis are at an improved risk of developing CRC. The Wnt/β-catenin pathway plays a key role in the onset of colorectal adenoma; in particular, intestinal cells first acquire loss-of-function mutations in the APC gene that induce the formation of adenomas. Wnt/β-catenin pathway APC, Wnt3a, Wnt5a, LEF1, and BCL9 genes and protein expression analyses were conducted by qRT-PCR and western blot in 68 colonic samples (polyps and adjacent mucosa) from 41 patients, of which 17 were affected by FAP. Ten normal colonic mucosal samples were collected from 10 healthy donors. In this study, both the APC gene and protein were less expressed in the colon tumor compared to the adjacent colonic mucosa. Conversely, the activated β-catenin was more expressed in polyps than in the adjacent mucosa. All results confirmed the literature data on carcinomas. A statistically significant correlation between Wnt3a and BCL9 both in polyps and in the adjacent mucosa underlines that the canonical Wnt pathway is activated in early colon carcinogenesis and that the adjacent mucosa is already altered. This is the first study analyzing the difference in expression of the Wnt/β-catenin pathway in human colorectal adenomas. Understanding the progression from adenomas to colorectal carcinomas is essential for the development of new therapeutic strategies and improving clinical outcomes with the use of APC and β-catenin as biomarkers.

Arthrospira (Spirulina) platensis feeding reduces the early stage of chemically induced rat colon carcinogenesis.

Colorectal cancer is the third most diagnosed cancer worldwide and linked to dietary/lifestyle factors. Arthrospira (Spirulina) platensis (AP) contains bioactive compounds with beneficial effects in vivo/in vitro. We evaluated the effects of AP feeding against 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis. Male Sprague Dawley rats were given subcutaneous injections of DMH (4 × 40 mg/kg body weight) (G1-G3) or vehicle (G4-G5) twice a week (weeks 3-4). During weeks 1-4, animals were fed a diet containing 1 % (G2) or 2 % (G3-G4) AP powder (w/w). After this period, all groups received a balanced diet until week 12. Some animals were euthanised after the last DMH injection (week 4) for histological, immunohistochemical (Ki-67, γ-H2AX and caspase-3) and molecular analyses (real time-PCR for 91 genes), while other animals were euthanised at week 12 for preneoplastic aberrant crypt foci (ACF) analysis. Both AP treatments (G2-G3) significantly decreased the DMH-induced increase in γ-H2AX (DNA damage) and caspase 3 (DNA damage-induced cell death) in colonic crypts at week 4. In addition, Cyp2e1 (Drug metabolism), Notch1, Notch2 and Jag1 genes (Notch pathway) and Atm, Wee1, Chek2, Mgmt, Ogg1 and Xrcc6 genes (DNA repair) were also down-regulated by 2 % AP feeding (G3) at week 4. A significant reduction in ACF development was observed in both AP-treated groups (G2-G3) at week 12. In conclusion, findings indicate that AP feeding reduced acute colonic damage after DMH, resulting in fewer preneoplastic lesions. Our study provided mechanistic insights on dietary AP-preventive effects against early colon carcinogenesis.

Anticarcinogenic activity of methanol extract of Melastoma malabathricum leaves is attributed to the presence of phenolics compounds and the activation of endogenous antioxidant system

Melastoma malabathricum (M. malabathricum) extracts have been reported to exert various pharmacological activities including antioxidants, anti-inflammatory and antiproliferative activities. The objective of the present study was to determine the anticarcinogenic activity of its methanol extract (MEMM) against the azoxymethane (AOM)-induced early colon carcinogenesis in rats. Rats were randomly assigned to five groups (n=6) namely normal control, negative control, and treatment (50, 250 or 500 mg/kg of MEMM) groups. Colon tissues were harvested for histopathological analysis and endogenous antioxidant system determination. MEMM was also subjected to HPLC analysis. Findings showed that MEMM significantly (p&lt;0.05) reversed the AOM-induced carcinogenicity by: i) reducing the formation of aberrant crypt foci (ACF) in colon tissues, and; ii) enhancing the endogenous antioxidant activity (catalase, superoxide dismutase and glutathione peroxidase). Moreover, various phenolics has been identified in MEMM. In conclusion, MEMM exerts the in vivo anticarcinogenic activity via the activation of endogenous antioxidant system and synergistic action of phenolics.

Chemoprevention of DMH-Induced Early Colon Carcinogenesis in Male BALB/c Mice by Administration of Lactobacillus Paracasei DTA81.

We evaluated the effects of the probiotic candidate Lactobacillus paracasei DTA81 (DTA81) on liver oxidative stress, colonic cytokine profile, and gut microbiota in mice with induced early colon carcinogenesis (CRC) by 1,2-dimethylhydrazine (DMH). Animals were divided into four different groups (n = 6) and received the following treatments via orogastric gavage for 8 weeks: Group skim milk (GSM): 300 mg/freeze-dried skim milk/day; Group L. paracasei DTA81 (DTA81): 3 × 109 colony-forming units (CFU)/day; Group Lactobacillus rhamnosus GG (LGG): 3 × 109 CFU/day; Group non-intervention (GNI): 0.1 mL/water/day. A single DMH dose (20 mg/kg body weight) was injected intraperitoneally (i.p), weekly, in all animals (seven applications in total). At the end of the experimental period, DTA81 intake reduced hepatic levels of carbonyl protein and malondialdehyde (MDA). Moreover, low levels of the pro-inflammatory cytokines Interleukin-6 (IL-6) and IL-17, as well as a reduced expression level of the proliferating cell nuclear antigen (PCNA) were observed in colonic homogenates. Lastly, animals who received DTA81 showed an intestinal enrichment of the genus Ruminiclostridium and increased concentrations of caecal acetic acid and total short-chain fatty acids. In conclusion, this study indicates that the administration of the probiotic candidate DTA81 can have beneficial effects on the initial stages of CRC development.

Probing the chemoprevention potential of the antidepressant fluoxetine combined with epigallocatechin gallate or kaempferol in rats with induced early stage colon carcinogenesis

The enhanced chemopreventive action against 1,2 Dimethylhydrazine (DMH)-induced preneoplastic lesion in rats could be achieved via simultaneous administration of the antidepressant fluoxetine (FLX) with two natural polyphenolic compounds viz., kaempferol (KMP) and/or epigallocatechin-gallate (EGCG). The obtained results revealed that single FLX pre-treatment possess a significant apoptotic effect by increasing the activity of serum and colon tissue caspase 3. It also attenuated the DMH driven increase in, colon tissue MDA, NO, PCNA and COX-2 expression as well as serum and colon tissue β-catenin, with a decrease in the multiplicity of ACF and number of MPLs. The combination of FLX with either KMP or EGCG improved the antioxidant, anti-inflammatory and antiproliferating activities but with higher apoptotic activity in case of KMP. Eventually, histopathological assessment of colon tissues exposed that while sole pre-treatment can improve DMH-induced hyperplasia with only moderate inflammatory infiltration, tissues from the combined pre-treatment regimens groups exhibited almost a normal colonic architecture with slight submucosal edema. The study proved that single FLX administration prior to DMH exerts a chemopreventive effect and that the investigated combined pre-treatment regimens demonstrated more potent chemopreventive and antiproliferative actions.

Administration of Metabiotics Extracted From Probiotic Lactobacillus rhamnosus MD 14 Inhibit Experimental Colorectal Carcinogenesis by Targeting Wnt/β-Catenin Pathway.

Background and Objective: The cellular microenvironment, diet, and lifestyle play a key role in the occurrence of colorectal cancer. Due to its rising trend, attempts are being made to devise novel biointerventions as adjunct to conventional therapies to prevent this deadly disease. “Metabiotics,” the beneficial metabolic signatures of probiotics are emerging as potential anticancer agent due to their ability to alter metabolic processes in the gut lumen and reduce the severity of colon carcinogenesis. Although beneficial attributes of metabiotics have been elucidated in vitro, yet their anticancer mechanism in vivo needs to be explored. Thus, the present study was performed to envisage anticancer potential of metabiotic extract obtained from indigenous probiotic, Lactobacillus rhamnosus MD 14, in early experimental colon carcinogenesis.Materials and Methods: Sprague–Dawley rats were daily administered with low, medium, and high dose of metabiotic extract orally along with a single dose of weekly intraperitoneal injection of 1,2-dimethylhydrazine up to 6 weeks and monitored for the markers of early colon carcinogenesis.Results: It was observed that the medium dose of metabiotic extract attenuated early colon carcinogenesis by reducing fecal procarcinogenic enzymes, oxidants, aberrant crypt foci, vis-à-vis downregulating oncogenes [K-ras, β-catenin, Cox-2, nuclear factor kappa B (NF-κB)] and upregulating tumor suppressor p53 gene leading to almost normal colon histology.Conclusions: It can be suggested that metabiotics modulate experimental colorectal cancer and could be used as a promising alternative of probiotics, particularly in immunocompromised individuals.

Probiotic Lactobacillus rhamnosus modulates the gut microbiome composition attenuates preneoplastic colorectal Aberrant crypt foci

Lactobacillus rhamnosus (LGG) is well documented strain with wide clinical applications. We investigated herein the possible protection role of LGG in against early preneoplastic colon carcinogenesis Aberrant crypt foci (ACF) in rat model. Sprague Dawley rats were pre-treated with or without LGG via oral gavage, followed by ACF induction with Dimethylhydrazine (DMH). LGG treated groups showed significant decrease in total number of ACF’s, and increased Bax, P53, and Caspase-3 proteins expression with significant attenuation of NFkB, Cox2 and β catenin expression compared to DMH group. Serum cytokines array revealed significant elevation of IL-2, IL-6, and IFN-γ, and attenuated level of IL-10 in LGG+DMH treated animals. Finally, the 16S rRNA fecal microbiome genomic analysis showed that LGG alters the gut microbiome structure, composition and functions at phylum, family and genus level. Collectively, LGG reduces colon ACFs incidence and multiplicity via inhibition of pro-carcinogenesis biomarkers and modulate the gut microbiome.

Probiotics (Lactobacillus acidophilus and Lactobacillus rhamnosus GG) in Conjunction with Celecoxib (selective COX-2 inhibitor) Modulated DMH-Induced Early Experimental Colon Carcinogenesis

Epidemiological and experimental observations have shown that nonsteroidal anti-inflammatory drugs especially selective cyclooxygenase-2 (COX-2) inhibitors and probiotics reduce the incidence risk of colon cancer. Therefore, the present study was designed to assess the prophylactic potentials of probiotics (Lactobacillus acidophilus and Lactobacillus rhamnosus GG) in conjunction with celecoxib, a selective cox-2 inhibitor in 1,2 dimethylhydrazine dihydrochloride (DMH)-induced experimental colon carcinogenesis, a well-established, well appreciated and widely used model for colorectal cancer that shares many similarities to human sporadic colorectal cancer with respect to response to some promotional and preventive agents. More specifically, it was observed that L. rhamnosus GG + celecoxib + DMH-treated animals had significantly reduced aberrant crypt foci (ACF) count and the expression of procarcinogenic molecular markers (β-catenin, NF-κB, and COX-2) in early experimental colon carcinogenesis compared with probiotic-DMH, celecoxib-DMH or DMH-treated animals. This is the first ever such study to demonstrate that probiotic in conjunction with celecoxib can be opted as an alternate prophylactic strategy in highly susceptible individuals to reduce both the incidence and severity of the life style diseases as prevention is better than cure.

Higher Order Chromatin Modulator Cohesin SA1 Is an Early Biomarker for Colon Carcinogenesis: Race-Specific Implications.

Alterations in high order chromatin, with concomitant modulation in gene expression, are one of the earliest events in the development of colorectal cancer. Cohesins are a family of proteins that modulate high-order chromatin, although the role in colorectal cancer remains incompletely understood. We, therefore, assessed the role of cohesin SA1 in colorectal cancer biology and as a biomarker focusing in particular on the increased incidence/mortality of colorectal cancer among African-Americans. Immunohistochemistry on tissue arrays revealed dramatically decreased SA1 expression in both adenomas (62%; P = 0.001) and adenocarcinomas (75%; P = 0.0001). RT-PCR performed in endoscopically normal rectal biopsies (n = 78) revealed a profound decrease in SA1 expression in adenoma-harboring patients (field carcinogenesis) compared with those who were neoplasia-free (47%; P = 0.03). From a racial perspective, colorectal cancer tissues from Caucasians had 56% higher SA1 expression than in African-Americans. This was mirrored in field carcinogenesis where healthy Caucasians expressed more SA1 at baseline compared with matched African-American subjects (73%; P = 0.003). However, as a biomarker for colorectal cancer risk, the diagnostic performance as assessed by area under ROC curve was greater in African-Americans (AUROC = 0.724) than in Caucasians (AUROC = 0.585). From a biologic perspective, SA1 modulation of high-order chromatin was demonstrated with both biophotonic (nanocytology) and chromatin accessibility [micrococcal nuclease (MNase)] assays in SA1-knockdown HT29 colorectal cancer cells. The functional consequences were underscored by increased proliferation (WST-1; P = 0.0002, colony formation; P = 0.001) in the SA1-knockdown HT29 cells. These results provide the first evidence indicating a tumor suppressor role of SA1 in early colon carcinogenesis and as a risk stratification biomarker giving potential insights into biologic basis of racial disparities in colorectal cancer. Cancer Prev Res; 9(11); 844-54. ©2016 AACR.

Abstract 845: Diet stamps on bugs: early life dietary energy intake impacts gut microbiota

Abstract The complex and dynamic interactions between diet, gut microbiota (GM) structure and function, and colon carcinogenesis are only beginning to be elucidated. We examined the colonic microbiota and aberrant crypt foci (ACF) in C57BL/6N female mice fed various dietary interventions (control, energy restricted and high-fat) provided during two phases (initiation and progression) of azoxymethane (AOM)-induced early colon carcinogenesis. During progression (wks. 22- 60), a high-fat diet enhanced ACF formation compared to a control or energy restricted diet. In contrast, energy restriction during initiation phase (wks. 3-21) enhanced ACF burden at 60 weeks, regardless of the diet in progression phase. Alterations in GM structure during the initiation phase diet were partially maintained after changing diets during the progression phase. However, diet during the progression phase had major effects on the mucosal GM that energy restriction in progression phase increased Firmicutes and reduced Bacteroidetes compared to a high-fat diet, regardless of initiation phase diet, suggesting that diet may have both transient effects as well as a lasting impact on GM composition. Integration of early life and adult dietary impacts on the colonic microbial structure and function with host molecular processes involved in colon carcinogenesis will be key to defining preventive strategies. Citation Format: Jinyu Xu, Jeffrey Galley, Michael Bailey, Jennifer Thomas-Ahner, Steven Clinton, Susan Olivo-Marston. Diet stamps on bugs: early life dietary energy intake impacts gut microbiota. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 845.

Effects of oat soluble and insoluble β-glucan on 1,2-dimethylhydrazine-induced early colon carcinogenesis in mice

ABSTRACTThe study is aimed at studying the effects of soluble and insoluble oat β-glucan on colon carcinogenesis in mice. One hundred and twenty male Kunming mice were divided into normal control (NC), model control (MC), high doses (100 mg/kg body weight) of soluble (H-SOG) and insoluble β-glucan (H-IOG), and low doses (50 mg/kg body weight) of soluble (L-SOG) and insoluble β-glucan (L-IOG) groups. The mice except those in the NC group were given subcutaneous injections of DMH to induce colon cancer. The bile acid content was significantly reduced but the colonic short-chain fatty acid content was enhanced (p < .05) in mice administered β-glucan, moreover, the tumor cells apoptosis was significantly promoted (p < .05), compared to the MC group. The effect of high doses β-glucan was better than the low doses, but there is little difference between the SOG and IOG. Results suggested that both SOG and IOG exert favorable effects in preventing colon cancer in a doses-dependent manner while the specific mechanism maybe different.

The Impact of Dietary Energy Intake Early in Life on the Colonic Microbiota of Adult Mice.

The complex and dynamic interactions between diet, gut microbiota (GM) structure and function, and colon carcinogenesis are only beginning to be elucidated. We examined the colonic microbiota and aberrant crypt foci (ACF) in C57BL/6N female mice fed various dietary interventions (control, energy restricted and high-fat) provided during two phases (initiation and progression) of azoxymethane (AOM)-induced early colon carcinogenesis. During progression (wks. 22–60), a high-fat diet enhanced ACF formation compared to a control or energy restricted diet. In contrast, energy restriction during initiation phase (wks. 3–21) enhanced ACF burden at 60 weeks, regardless of the diet in progression phase. Alterations in GM structure during the initiation phase diet were partially maintained after changing diets during the progression phase. However, diet during the progression phase had major effects on the mucosal GM. Energy restriction in the progression phase increased Firmicutes and reduced Bacteroidetes compared to a high-fat diet, regardless of initiation phase diet, suggesting that diet may have both transient effects as well as a lasting impact on GM composition. Integration of early life and adult dietary impacts on the colonic microbial structure and function with host molecular processes involved in colon carcinogenesis will be key to defining preventive strategies.

Downregulation of Novel Tumor Suppressor Gene SA-1 in Early Colon Carcinogenesis Has a Predilection for Blacks: Potential Biological Underpinnings for Colorectal Cancer (CRC) Disparities

Downregulation of Novel Tumor Suppressor Gene SA-1 in Early Colon Carcinogenesis Has a Predilection for Blacks: Potential Biological Underpinnings for Colorectal Cancer (CRC) Disparities

Sa1911 Mitochondrial Alterations in Early Colon Carcinogenesis: Evidence for Warburg Effect in the Initiation of Colorectal Cancer (CRC) Carcinogenesis

Background: There is emerging realization of the central role of metabolism in carcinogenesis with the Warburg effect (preferential utilization of glycolysis in normoxic environment) (e.g. Weinberg, Cell 2012). We have previously noted an increase in microvascular blood supply in the predysplastic colonic mucosa (field carcinogenesis) (Gut 2005, Gastro 2008, Clin Cancer Res 2009, Cancer Prev Res 2010) which may reflect altered metabolism, however molecular determinants remain unexplored. The role of mitochondria in CRC is well established in frank tumors with dysfunction reflected by increased fission leading to less efficient oxidative phosphorylation, enabling shunting of precursors for cell growth. However, the presence of mitochondrial dysfunction and Warburg effect in early colon carcinogenesis has yet been explored. Therefore, we chose to investigate potential mitochondrial changes in the pre-malignant colon. Methods: To investigate mitochondrial changes we incorporated both human and animal studies: For human studies we obtained biopsies from endoscopically normal rectal muscosa from 80 patients undergoing screening colonoscopies. Samples were processed for gDNA and RNA isolation. Real Time PCRwas conducted to assess mitochondrial mass, OPA-1, UCP2, and PKM2 expression. For animal experiments we utilized the Polypopsis in Rat Colon (Pirc) rat, which possesses an APC truncation, consistent with the initiating factor in ~80% of sporadic CRCs. 7 Pirc rats with age-matched controls were euthanized after 24 wks of age. Colons were excised from these animals to obtain colonic gDNA and RNA. Real Time PCR was conducted to assess mitochondrial mass, OPA-1 and UCP2 expression. Results: In patient biopsies, mitochondrial mass was shown to be upregulated with adenomal presence (~72% increase, p=0.05). Pirc rats were also shown to possess a 63.6% induction of mitochondrial mass (p=0.03). OPA-1 expression was upregulated in both patients with adenomas as well as Pirc rats (49%, p=0.05 and 67%, p<0.03 respectively). Induction of UCP2 was detected in patients with adenomas (99%, p<0.04) and in Pircs (101%, p=0.05). Interestingly, patients with lesions had a 80% increase in PKM2 (p=0.002), suggestive of a Warburg effect in early colon carcinogenesis. Conclusions: We demonstrate for the first time, that in the predysplastic mucosa there is profound metabolic alterations consistent with a Warburg effect. Specifically, we noted increased mitochondria mass (fission) which suppresses oxidative phosphorylation. Aside from structural alterations, electron transport system is further inhibited by overexpression of UCP2. Biologically, this provides insight into early metabolic events in colon carcinogenesis. Clinically, these insights may enable novel biomarkers for early detection and also a myriad of potentially druggable targets for chemoprevention.

Sa1960 Novel Epigenetic: Metabolic Axis in Early Colon Carcinogenesis and NSAIDs Resistance: Potential Role of Adipogenic Regulator PRDM16

Sa1960 Novel Epigenetic: Metabolic Axis in Early Colon Carcinogenesis and NSAIDs Resistance: Potential Role of Adipogenic Regulator PRDM16

Colonic mucosal fatty acid synthase as an early biomarker for colorectal neoplasia: modulation by obesity and gender.

We have previously reported that colonic pericryptal microvascular blood flow is augmented in the premalignant colonic epithelium, highlighting the increased metabolic demand of the proliferative epithelium as a marker of field carcinogenesis. However, its molecular basis is unexplored. In this study, we assessed the expression of a regulator of the "lipogenic switch," fatty acid synthase (FASN), in early colon carcinogenesis for its potential biomarker utility for concurrent neoplasia. FASN expression (IHC) in the colonic epithelium from azoxymethane and polyposis in rat colon (Pirc) models of colorectal cancer was studied. FASN mRNA expression from endoscopically normal rectal mucosa was evaluated and correlated with colonoscopic findings (pathologic confirmation of neoplasia). FASN expression progressively increased from premalignant to malignant stage in the azoxymethane model (1.9- to 2.5-fold; P < 0.0001) and was also higher in the adenomas compared with adjacent uninvolved mucosa (1.8- to 3.4-fold; P < 0.001) in the Pirc model. Furthermore, FASN was significantly overexpressed in rectal biopsies from patients harboring adenomas compared with those with no adenomas. These effects were accentuated in male (∼2-fold) and obese patients (1.4-fold compared with those with body mass index < 30). Overall, the performance of rectal FASN was excellent (AUROC of 0.81). FASN is altered in the premalignant colonic mucosa and may serve as a marker for colonic neoplasia present elsewhere. The enhanced effects in men and obesity may have implications for identifying patient subgroups at risk for early-onset neoplasia. These findings support the role of rectal FASN expression as a reliable biomarker of colonic neoplasia.

Abstract 5344: Rapid induction and progression of PhIP+DSS-induced colon carcinogenesis in CYP1A-humanized mice

Abstract 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), the most abundant heterocyclic amine generated from high temperature cooking of meat and fish, is metabolically activated by human cytochrome P450 (CYP)1A2 to a proximate carcinogen. Using CYP1A-humanized (hCYP1A) mice, previous study in our lab demonstrated that a single i.g. administration of PhIP (200mg/kg b.w.), followed by 1.5% Dextran Sodium Sulfate (DSS) in drinking water for 7 days, can rapidly induce tumors in the colon with 100% incidence. Multiple adenocarcinomas were observed with elevation of β-catenin, a key protein in the Wnt signaling pathway, as well as iNOS, COX-2, cyclin D1 and c-Myc. In the present study, we investigated the early stage colon carcinogenesis in the hCYP1A mice treated with PhIP (2x 100mg/kg b.w.) and DSS (4 days). After 4 days of DSS treatment, clinical manifestation such as weight loss, diarrhea, and bloody stools were observed. At day 1 after DSS cessation, we found severe damages to the colon epithelium with expansive crypt degeneration, ulcerations and inflammation. At days 3 and 7, we detected epithelial hyperplasia and dysplasia in addition to extensive ulcerations and inflammation. At days 11 and 17, we identified early adenoma and adenocarcinoma, respectively. Similar adenomatous lesions were not observed in hCYP1A mice treated with only DSS. Using immunohistochemistry, we detected strong nuclear staining of β-catenin, specifically within the early adenomas and adenocarcinomas. Further examination using Ki67 marker revealed strong nuclear staining in the adenomas and adenocarcinomas as well as areas of hyperplasia and dysplasia, indicating their high level of proliferation and generation. DNA sequencing revealed 96% of the PhIP+DSS induced colon tumors at week 10 carried a β-catenin mutation, particularly in the codon 32, 33, and 34. Altogether, we demonstrate the rapid induction and progression of colon tumorigenesis in hCYP1A mice, initiated by PhIP-induced Wnt dysregulation and promoted by DSS-induced colitis. (Supported by NIH grants F31CA168333, RO1CA120915 and RO1CA133021 as well as shared facilities funded by CA72720 and ES05022) Citation Format: Jayson X. Chen, Hong Wang, Guangxun Li, Anna Liu, Chung S. Yang. Rapid induction and progression of PhIP+DSS-induced colon carcinogenesis in CYP1A-humanized mice. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5344. doi:10.1158/1538-7445.AM2014-5344

Sa1927 SIRT 6: Linking Metabolic and Microvascular Alterations in Early Colon Carcinogenesis

Sa1927 SIRT 6: Linking Metabolic and Microvascular Alterations in Early Colon Carcinogenesis

Prebiotic Inulin Alters the Colonic Mass, pH, Microflora and Short Chain Fatty Acids in 1,2-Dimethylhydrazine Dihydrochloride Induced Early Colon Carcinogenesis in Male Laca Mice

Prebiotics have been found to have prophylactic potentials against colon cancer. Thus, the present study was designed to delineate the prophylactic role of prebiotics in experimental colon carcinogenesis. It was found that inulin+DMH-treated mice had significantly increased (p<0.05) body mass till 5th week and thereafter, decreased while in lactulose+DMH-treated mice the body mass increased significantly (p<0.05) from 5th week till end of experiment compared with DMH-only treated mice. Further, it was observed that mice belonging to inulin+DMH and lactulose+DMH-treated groups had significantly (p<0.05) higher lactobacilli counts compared with DMH-only-treated mice. It was also observed that inulin+DMH-treated mice had significantly (p<0.05) decreased colonic pH compared with lactulose +DMH treated mice while no significant difference was found in the colonic mass. Short chain fatty acid mainly butyric acid increased significantly (p<0.05) in inulin+DMH and lactulose+DMH-treated mice compared with DMH-only-treated mice. Thus, it can be concluded that probiotic inulin had better anticarcinogenic property than lactulose in reducing the DMH induced colonic alterations.