Role In Development Of Colorectal Cancer Research Articles

Expression levels of miR-143-3p and -424-5p in colorectal cancer and their clinical significance.

Colorectal cancer (CRC) is one of the most prevalent cancers and microRNAs are involved in colorectal carcinogenesis and progression. The role of our candidate microRNAs (miR-143-3p, -424-5p, -212-3p and -34a-3p) have been investigated in various cancers. The aim of the current study was to evaluate expression levels of microRNAs (miR-143-3p, -424-5p, -212-3p and -34a-3p) in the sera of patients with CRC in order to identify potential non-invasive biomarker for CRC and investigate the relationship between their expression and clinicopathological features of CRC. The serological expression of candidate microRNAs were measured in 124 participants, including 62 CRC patients and 62 healthy controls and the serum expression levels of candidate miRNAs were quantified by stemloop reverse transcriptionquantitative polymerase chain reaction. In the present study, results showed a significant upregulation expression level of miR-424-5p (P< 0.001) and decreased expression level of miR143-3p was observed in the sera of patients with CRC (P< 0.001). Receiver operating characteristic (ROC) curve analysis demonstrated the area of miR-424-5p and miR-143-3p under the ROC curve for CRC diagnosis were 0.703 and 0.724 respectively (P< 0.001). In addition, down expression of miR-143-3p was significantly associated with tumor size (P= 0.005) and lymph node metastasis (P= 0.020) in CRC patients. The present investigation suggested that low expression of miR-143-3p and increasing level of miR-424-5p in CRC patients may play an important role in development of CRC and they could function as potential non-invasive biomarkers for CRC.

Differential Responses of Colorectal Cancer Cell Lines to Enterococcus faecalis' Strains Isolated from Healthy Donors and Colorectal Cancer Patients.

The metabolites produced by the host’s gut microbiota have an important role in the maintenance of intestinal homeostasis, but can also act as toxins and induce DNA damage in colorectal epithelial cells increasing the colorectal cancer (CRC) chance. In this scenario, the impact of some of the components of the natural human gastrointestinal microbiota, such as Enterococcus faecalis (E. faecalis), at the onset of CRC progression remains controversial. Since under dysbiotic conditions it could turn into a pathogen, the aim of this study was to compare the effect of E. faecalis’ strains (isolated from CRC patients and healthy subjects’ stools) on the proliferation of different colorectal cells lines. First, we isolated and genotyping characterized the Enterococcus faecalis’ strains. Then, we analyzed the proliferation index (by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay) of three tumor and one normal intestinal cell lines, previously exposed to E. faecalis strains pre-cultured medium. Stool samples of CRC patients demonstrated a reduced frequency of E. faecalis compared to healthy subjects. In addition, the secreted metabolites of E. faecalis’ strains, isolated from healthy donors, decreased the human ileocecal adenocarcinoma cell line HCT-8 and human colon carcinoma cell line HCT-116 cell proliferation without effects on human colorectal adenocarcinoma cell line SW620 and on normal human diploid cell line CLR-1790. Notably, the metabolites of the strains isolated from CRC patients did not influence the cell growth of CRC cell lines. Our results demonstrated a new point of view in the investigation of E. faecalis’ role in CRC development, which raises awareness of the importance of not only associating the presence/absence of a unique microorganism, but also in defining the specific characteristics of the different investigated strains.

MTERFD1 promotes cell growth and irradiation resistance in colorectal cancer by upregulating interleukin-6 and interleukin-11.

The role of the novel oncogene, mitochondrial transcription termination factor (MTERFD1), in human colorectal cancer (CRC) is unclear. Here, we report the role MTERFD1 in CRC. We conducted plasmid construction and transfection analyses, cell proliferation assays, apoptosis detection assays, ELISA, western blotting, and qRT-PCR using cell culture applications. MTERFD1 was upregulated in human and chemically induced mouse CRC tissues. In vitro functional assays showed that MTERFD1 overexpression promoted human CRC cell proliferation, whereas knockdown of endogenous MTERFD1 significantly enhanced apoptosis in these cells. MTERFD1 expression was positively linked to irradiation resistance in CRC cells. Furthermore, interleukin (IL)-6 and IL-11 were identified as the effector molecules of MTERFD1 in its oncogenic role and irradiation resistance in CRC cells. Our results demonstrated that MTERFD1 played an oncogenic role in CRC development and enhanced irradiation resistance by regulating IL-6 and IL-11 in CRC cells. MTERFD1 may serve as a potential prognostic and therapeutic marker for radiotherapy in CRC.

MiR-506 Suppresses Colorectal Cancer Development by Inhibiting Orphan Nuclear Receptor NR4A1 Expression.

NR4A1 acts as an oncogene and plays an important role in colorectal cancer development and progression, but little is known about the regulatory mechanism of NR4A1 expression. MicroRNA (miRNA) is involved in the progression of various tumors, affecting proliferation, apoptosis or migration. We aimed to elucidate whether miRNA regulates NR4A1 expression and determine its underlying significance in colorectal cancer. By using the TargetScan database, we identified a miR-506 binding site in the NR4A1 3'-UTR. Examination of colorectal cancer tissues and cells revealed that NR4A1 mRNA and protein were up-regulated, while miR-506 expression was down-regulated. Spearman correlation analysis revealed that expression of NR4A1 mRNA was negatively correlated with miR-506 levels in colorectal cancer tissue. Further studies indicated that miR-506 decreased NR4A1 expression through directly targeting the NR4A1 mRNA 3'-UTR. Functional experiments showed that rescue of NR4A1 expression in cells reversed the inhibitory effects of miR-506 on proliferation, migration and invasion of colorectal cancer cells. In conclusion, miR-506 acts as a tumor suppressor and inhibits proliferation, migration and invasion in colorectal cancer cells partly through decreasing NR4A1 expression.

Nitric oxide synthase inhibitors 1400W and L-NIO inhibit angiogenesis pathway of colorectal cancer

BackgroundIt has been widely accepted that angiogenesis plays fundamental roles in colorectal cancer development, and therapeutic targeting of this pathway has achieved promising outcome. Recent reports have highlighted the involvement of nitric oxide synthases (NOS) in the development of angiogenesis in cancer; however, the mechanism and therapeutic value of NOS inhibitors in colon cancer are largely unknown. ObjectiveIn this study, we investigated the effects and mechanism of the NOS inhibitors 1400W and L-NIO on the angiogenesis pathway in colorectal cancer cells. MethodsTwo colorectal cancer cell lines, HT 29 and HCT 116, were used for in vitro study. The expression of iNOS and eNOS in cells was knocked down via shRNA transfection. MTS assays and wound healing assays were performed to assess cell proliferation and migration after shRNA transfection or treatment with 1400W, L-NIO, and 5-fluorouracil. Human angiogenesis PCR arrays and proteome profiler human angiogenesis arrays were used to detect changes in key genes/proteins involved in modulating angiogenesis after 1400W and L-NIO treatment. ResultsKnockdown of iNOS and eNOS significantly inhibited colorectal cancer cell growth. Treatment with NOS inhibitors inhibited colorectal cancer cell growth and migration, and was associated with suppression of the expression of key genes/proteins involved in the angiogenesis pathway. In addition, the combined use of NOS inhibitors with 5-fluorouracil showed enhanced inhibition of cell proliferation and migration. ConclusionNOS inhibitors could suppress colorectal cancer cell growth and migration, likely via suppressing the angiogenesis pathway.

A12913 Role of (Pro)renin receptor in the pathogenesis of colorectal cancer

Objectives: Although constructive activating mutations of Wnt/β-catenin signaling pathway play an important role in colorectal cancer development, basal activation of canonical signaling with Wnt ligands is also essential for sufficient activation of β-catenin. The present study was performed to investigate the role of (pro)renin receptor ((P)RR) in the activation of Wnt/β-catenin pathway and pathogenesis of colorectal cancer. Methods: (P)RR inhibition was conducted by siRNA in cultured human colorectal cancer cells with constructive activating mutations in Wnt/β-catenin signaling pathway. (P)RR overexpression was conducted in cultured normal colon epithelial cells by vector transfection. Wnt signaling activity was measured using β-catenin reporter and dual luciferase assay. Cell proliferation was evaluated by WST-1 assay in vitro and subcutaneous tumor xenograft formation in vivo. Results: (P)RR expression was significantly increased in human cancer tissues and cultured cancer cell lines. Furthermore, positive relationship was observed between cancer tissue (P)RR expression and poorly-differentiated, advanced or early progressed cancer. (P)RR inhibition significantly attenuated Wnt/β-catenin pathway and proliferation of colorectal cancer cells both in vitro and vivo. On the other hand, (P)RR overexpression activated Wnt/β-catenin pathway and enhanced proliferation in normal colon epithelial cells. Conclusion: These data indicate that aberrant (P)RR expression promotes colorectal cancer development through the activation of Wnt/β-catenin signaling pathway despite of its constructive activating mutations.

Mesenchymal marker and LGR5 expression levels in circulating tumor cells correlate with colorectal cancer prognosis.

The presence of circulating tumor cells (CTCs) has been found to correlate with colorectal cancer (CRC) prognosis, whereas epithelial-mesenchymal transition (EMT) in CTCs has been found to be associated with CRC metastasis. LGR5 is a known target of Wnt signaling and plays an important role in CRC development. The aim of this study was to assess the clinical relevance of EMT and LGR5 expression in CTCs from CRC patients. Sixty-six CRC patients were included in this study. The detection and expression of EMT phenotypes in CTCs from these patients were assessed using CanPatrol™ CTC enrichment and mRNA in situ hybridization (ISH), respectively. LGR5 expression in the CTCs was assessed using mRNA ISH. CTCs were detected in 86.4% (57/66) of the CRC patients included. Both the numbers of total CTCs and of CTCs displaying a mesenchymal phenotype (M+ CTCs) were found to significantly correlate with advanced disease stages and the occurrence of metastasis (p < 0.05). An adjusted multivariate analysis also indicated that the number of M+ CTCs significantly correlated with the occurrence of metastasis (p = 0.031). Additionally, we found that a high LGR5 expression level significantly correlated with the occurrence of metastasis (p < 0.05). We also found that the presence of ≥ 6 CTCs or ≥ 3M+ CTCs per 5ml blood significantly correlated with disease progression (p < 0.05). Patients with ≥ 6 CTCs or ≥ 3M+ CTCs per 5ml blood were found to exhibit poorer progression-free survival (PFS) and overall survival (OS) rates (p < 0.05 in all cases). Using Cox regression analyses, we found that only total CTC numbers remained as independent prognostic factors for a worse PFS (p = 0.043). From our data we conclude that CTC numbers and EMT phenotypes may serve as prognostic markers for disease progression and metastasis in CRC patients. In addition, we conclude that LGR5 expression in CTCs may serve as a marker for CRC metastasis.

Impact of pigment epithelium-derived factor on colorectal cancer in vitro and in vivo.

Pigment epithelial derived factor (PEDF) is a secreted glycoprotein that is a non-inhibitory member of the serine protease inhibitor (serpin) family. PEDF exhibits multiple biological properties including neuroprotective, anti-angiogenic, and immune-modulating. Interestingly, PEDF exerts the inhibitory effects in cancers derived from certain tissues, including prostatic, ovarian, and pancreatic carcinomas. The current study aimed to elucidate its role in colorectal cancer development. PEDF expression in human colorectal cancer tissue was assessed using quantitative polymerase chain reaction (qPCR) and immunohistochemical staining (IHC). The effect of treatment with recombinant PEDF on cellular function was examined using in vitro functional assays. PEDF expression was downregulated in colorectal cancer cell tissue. Treatment with recombinant PEDF resulted in significant decreases in the rate of colorectal cancer cell migration and invasion and an increase in cellular adhesion in colorectal cancer cell lines examined. These results indicate that upregulation of PEDF expression may serve as a new strategy for further investigation of therapeutic relevance to the prevention of the metastatic spread of colorectal cancer.

Solute carrier family 34 member 2 overexpression contributes to tumor growth and poor patient survival in colorectal cancer

Solute carrier family 34 member 2 (SLC34A2) is a well-known sodium-dependent phosphate transporter that has recently been linked to cancer development. However, its specific oncogenic role remains controversial in numerous human malignancies, and is currently unknown in colorectal cancer (CRC). Therefore, in this study we firstly used Oncomine database to determine its expression in cancer tissues and found it is overexpressed in thyroid, ovarian and renal cancer, while it is opposite in lung, breast and pancreas cancer. Using qRT-PCR and western blot, we then demonstrated its overexpression in CRC tissues as compared with adjacent normal tissues (n = 20). In a retrospective cohort enrolling 190 CRC patients, we proved its expression was significantly correlated with N stage. Furthermore, high SLC34A2 expression is associated with higher postoperative metastasis rate and serves as an independent adverse factor affecting patient prognosis. In subgroup analysis, SLC34A2 expression could stratify the patient prognosis in stage II and III CRC, but failed in stage IV CRC. In cellular assays in vitro, knockdown of SLC34A2 dramatically inhibited the proliferation and colony formation, induced the apoptosis and arrests the cell cycle progression of HCT-116 CRC cells. In cellular assays in vivo, knockdown of SLC34A2 significantly inhibited the growth of xenografts, decreasing Ki-67 and proliferating cell nuclear antigen (PCNA) expression and increasing apoptosis rate. Taken together, our study indicates SLC34A2 plays a crucial promoting role in CRC development and therefore has great potential to be further developed as a reliable biomarker for CRC diagnosis and treatment.

Omega-3 PUFA Loaded in Resveratrol-Based Solid Lipid Nanoparticles: Physicochemical Properties and Antineoplastic Activities in Human Colorectal Cancer Cells In Vitro.

New strategies are being investigated to ameliorate the efficacy and reduce the toxicity of the drugs currently used in colorectal cancer (CRC), one of the most common malignancies in the Western world. Data have been accumulated demonstrating that the antineoplastic therapies with either conventional or single-targeted drugs could take advantage from a combined treatment with omega-3 polyunsaturated fatty acids (omega-3 PUFA). These nutrients, shown to be safe at the dosage generally used in human trials, are able to modulate molecules involved in colon cancer cell growth and survival. They have also the potential to act against inflammation, which plays a critical role in CRC development, and to increase the anti-cancer immune response. In the present study, omega-3 PUFA were encapsulated in solid lipid nanoparticles (SLN) having a lipid matrix containing resveratrol esterified to stearic acid. Our aim was to increase the efficiency of the incorporation of these fatty acids into the cells and prevent their peroxidation and degradation. The Resveratrol-based SLN were characterized and investigated for their antioxidant activity. It was observed that the encapsulation of omega-3 PUFA into the SLN enhanced significantly their incorporation in human HT-29 CRC cells in vitro, and their growth inhibitory effects in these cancer cells, mainly by reducing cell proliferation.

Dietary Factors Modulate Colonic Tumorigenesis Through the Interaction of Gut Microbiota and Host Chloride Channels.

In recent decades, the association among diet, gut microbiota, and the risk of colorectal cancer (CRC) has been established. Gut microbiota and associated metabolites, such as bile acids and butyrate, are now known to play a key role in CRC development. The aim of this study is to identify that the progression to CRC is influenced by cholic acid, sodium butyrate, a high-fat diet, or different dose of dihydromyricetin (DMY) interacted with gut microbiota. An AOM/DSS (azoxymethan/dextran sodium sulfate) model is established to study the gut microbiota compsition before and after tumor formation during colitis-induced tumorigenesis. All above dietary factors profoundly influence the composition of gut microbiota and host colonic tumorigenesis. In addition, mice with DMY-modified initial microbiota display different degrees of chemically induced tumorigenesis. Mechanism analysis reveals that gut microbiota-associated chloride channels participated in colon tumorigenesis. Gut microbiota changes occur in the hyperproliferative stage before tumor formation. Gut microbiota and host chloride channels, both of which are regulated by dietary factors, are associated with CRC development.

The controversial role of Enterococcus faecalis in colorectal cancer.

Colorectal cancer (CRC) is a complex and widespread disease, currently ranked as the third most frequent cancer worldwide. It is well known that the gut microbiota has an essential role in the initiation and promotion of different cancer types, particularly gastrointestinal tumors. In fact, bacteria can trigger chronic inflammation of the gastric mucosal, which can induce irreversible changes to intestinal epithelial cells, thus predisposing individuals to cancer. Some bacterial strains, such as Helicobacter pylori, Streptococcus bovis, Bacteroides fragilis, Clostridium septicum and Fusobacterium spp. have a well established role in CRC development. However, the role of Enterococcus faecalis still remains controversial. While part of the literature suggests a harmful role, other papers reported E. faecalis as an important probiotic microorganism, with great applicability in food products. In this review we have examined the vast majority of published data about E. faecalis either in CRC development or concerning its protective role. Our analysis should provide some answers regarding the controversial role of E. faecalis in CRC.

An Integrated Approach for Identification of Functionally Similar MicroRNAs in Colorectal Cancer.

Colorectal cancer (CRC) is one of the most prevalent cancers around the globe. However, the molecular reasons for pathogenesis of CRC are still poorly understood. Recently, the role of microRNAs or miRNAs in the initiation and progression of CRC has been studied. MicroRNAs are small, endogenous noncoding RNAs found in plants, animals, and some viruses, which function in RNA silencing and posttranscriptional regulation of gene expression. Their role in CRC development is studied and they are found to be potential biomarkers in diagnosis and treatment of CRC. Therefore, identification of functionally similar CRC related miRNAs may help in the development of a prognostic tool. In this regard, this paper presents a new algorithm, called μSim. It is an integrative approach for identification of functionally similar miRNAs associated with CRC. It integrates judiciously the information of miRNA expression data and miRNA-miRNA functionally synergistic network data. The functional similarity is calculated based on both miRNA expression data and miRNA-miRNA functionally synergistic network data. The effectiveness of the proposed method in comparison to other related methods is shown on four CRC miRNA data sets. The proposed method selected more significant miRNAs related to CRC as compared to other related methods.

MicroRNA-552 promotes tumor cell proliferation and migration by directly targeting DACH1 via the Wnt/β-catenin signaling pathway in colorectal cancer.

The purpose of the present study was to analyze the crucial role of microRNAs (miRNAs/miRs) involved in the proliferation and migration of colorectal cancer (CRC) and to investigate their underlying mechanisms. The present study discusses the expression and function of miR-552 in CRC. The expression level of miR-552 in CRC cells and tissues was observed, and it was suggested that the high expression of miR-552 accelerated the proliferation and migration of CRC cells in vitro. Notably, a result of the present study was that the cell fate determination factor Dachshund family transcription factor 1 (DACH1) was identified as a direct target of miR-552. Suppressing miR-552 expression in CRC cells increased endogenous DACH1 mRNA and protein levels, which was negatively correlated with miR-552. DACH1 performs an important role in the development of a number of neoplasms, and has the ability to regulate the Wnt/β-catenin signaling pathway as a novel predictive and diagnostic biomarker. Accordingly, it was concluded that miR-552 exerted a tumor-promoting role in CRC development by targeting DACH1, which may contribute to the increase in the rates of CRC proliferation and migration. miR-552 may serve as a potential diagnostic and prognostic biomarker for CRC.

Abstract 5721: Genome-wide discovery and identification of a novel microrna signature for recurrence prediction in colorectal cancer

Abstract Purpose: Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. In 2016, there were estimated 95,270 newly diagnosed CRC cases, and 49,190 deaths from this disease in the United States. Survival of patients is closely associated with the tumor stage at the time of diagnosis as 5-year relative survival rates range from 65% for all stages, 90% for localized primary tumor, 71% for regional metastasis and 13% for distant metastasis. Post-surgery, adjuvant therapy is only recommended to those with high risk stage II, as well as stage III and IV tumors. However, approximately 40-50% of the patients undergo curative surgery only and 20-30% that are treated with adjuvant chemotherapy, eventually relapse and experience a metastatic disease and eventual death. The current gold standard TNM (Tumor, Node, Metastasis) staging for determining the prognosis of CRC patients remains inadequate at identification of high-risk stage II and III patients that have a high potential of developing tumor recurrence. MicroRNAs (miRNAs) play an important role in CRC development and are emerging as important disease biomarkers. Therefore, in this study we sought to determine the prognostic potential of the miRNAs using a systematic, genome-wide biomarker discovery approach, followed by validation of biomarkers in multiple patient cohorts Experimental design: Three independent publicly available genome-wide miRNA expression datasets were used for miRNA biomarker discovery (n=158) and validation (n=109 and n=40) of this miRNA signature for recurrence prediction in stage II and III CRC using multivariate Cox regression analysis. The eight gene miRNA signature discovered from the genome-wide analysis was analytically validated in two independent patient cohorts (n=127 and n=96) using Taqman-based RT-PCR assays. Results: The genome-wide comprehensive analysis led to the identification of an eight gene miRNA classifier that significantly predicted recurrence free survival (RFS) in training (log-rank p=0.003) and two independent validation cohorts (log-rank p&amp;lt;0.0001 and p=0.002). The RT-PCR based training and validation of the eight gene classifier in two independent clinical cohorts significantly associated with poor prognosis in stage II and III CRC patients (log-rank p&amp;lt;0.004 and p&amp;lt;0.0001). Multivariate analyses performed in these two patient cohorts revealed that the eight gene miRNA classifier served as an independent predictor of poor prognosis in stage II and III CRC patients. Conclusions: In conclusion, we have identified a novel miRNA-based classifier, which is robustly predictive of poor prognosis in patents with stage II/III CRC, and might facilitate identification and stratification of high-risk patients that are candidates for adjuvant chemotherapy and clinical surveillance. Citation Format: Raju Kandimalla, Feng Gao, Naoki Takahashi, Yasuhide Yamada, Takatoshi Matsuyama, Toshiyaki Ishikawa, Xin Wang, Ajay Goel. Genome-wide discovery and identification of a novel microrna signature for recurrence prediction in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5721. doi:10.1158/1538-7445.AM2017-5721

Serrated Polyps of Colon and Rectum: a Clinicopathologic Review.

In the past decade, there have been significant changes in the classification and nomenclature of colorectal polyps. Previously, only two groups of lesions were widely recognized, the adenoma and the hyperplastic polyp. Adenomas were considered the only precursor of colorectal cancer, and hyperplastic polyps were considered innocent with no malignant potential. However, recent discoveries about molecular pathways of colorectal cancers have significantly changed our understanding of these neoplasms. Serrated polyps-previously uniformly called hyperplastic polyps-are now known to comprise a heterogeneous family of neoplasms united by their characteristic saw tooth morphology but differing in many important ways, including their malignant potential and molecular profile. This group of neoplasms includes both hyperplastic polyps and the more recently recognized serrated adenomas. Serrated adenomas can be subdivided into the traditional serrated adenoma and the sessile serrated adenoma/polyp. Both of these lesions show characteristic molecular changes, which differ from traditional colorectal adenomatous polyps. In this review, we will discuss the morphologic features of serrated colorectal lesions, the molecular alterations that characterize them, and their role in colorectal cancer development. The English literature regarding the new nomenclature will be reviewed and the key diagnostic points will be recorded. This large group of polyps has recently been better classified which needs specific attention by pathologists, gastroenterologists and even surgeons.

Prevalence of pks-positive Escherichia coli in Japanese patients with or without colorectal cancer

BackgroundRecent studies show that some Escherichia coli strains possessing a gene cluster named the pks island might have a causative role in the development of human colorectal cancer (CRC). In several reports from Europe, they are found more prevalently in colon tissue specimens derived from CRC patients compared to those from controls. In this study we sought to clarify the difference in pks prevalence between CRC patients and non-CRC controls in the Japanese population, by using non-invasive sample collection technique during colonoscopy.MethodsColonic lavage samples were collected during diagnostic colonoscopy, and bacterial DNA within each sample was extracted. Fecal DNA samples were then examined for pks island genes using conventional qualitative PCR and real-time quantitative PCR. In some patients biopsy samples were also collected in the same session of colonoscopy, and the correlation between the pks status of the colonic lavage sample and the biopsy sample of the same patients was evaluated.ResultsTwelve out of thirteen patients (92%) showed the same pks status by colonic lavage sample and biopsy sample, suggesting the usefulness of colonic lavage samples as a surrogate for biopsy samples. A total of 98 colonic lavage samples were collected, which included 35 from CRC patients, 37 from adenoma patients, and 26 from controls. The pks-positive bacterial DNA was detected in 43, 51, and 46% of colonic lavage samples from CRC, adenoma, and control patients, respectively, and there was no significant difference among diseases. Real-time quantitative PCR showed no significant difference in the relative concentrations of pks-positive bacterial DNA among diseases. Age, gender, location of CRC, CRC staging, or k-ras gene status was not associated with pks prevalence.ConclusionsAlthough the method of collecting fecal DNA from colonic lavage samples was safe and technically feasible, factors other than pks-positive bacteria appear to play more important roles in CRC development in this cohort.

CDK5 functions as a tumor promoter in human colorectal cancer via modulating the ERK5-AP-1 axis.

Abnormal expression of cyclin-dependent kinase 5 (CDK5) has been found in several human cancers, whereas the role of CDK5 in the malignant development of colorectal cancer (CRC) has not been well characterized. Here we investigated the role of CDK5 in CRC and found that its expression was much higher in CRC tissues than that in normal tissues with a higher expression level of CDK5 closely correlating to advanced American Joint Committee on Cancer (AJCC) stage, poor differentiation, increased tumor size and poor prognosis of CRC. Biological function experiments showed that CDK5 regulated CRC cell proliferation and metastasis ability. Whole-genome microarray analysis, co-immunoprecipitation, in vitro kinase assay, western blotting, luciferase reporter assays and electrophoretic mobility shift assay (EMSA) showed that CDK5 could directly phosphorylate ERK5 at threonine (Thr) 732 and finally modulate the oncogenic ERK5–AP-1 axis. Further researches showed that CDK5–ERK5–AP-1 axis could promote progression of CRC carcinogenesis and had a significant correlation in human CRC samples. In summary, this study revealed the functional and mechanistic links between CDK5 and the oncogenic ERK5–AP-1 signaling pathway in the pathogenesis of CRC. These findings suggest that CDK5 has an important role in CRC development and may serve as a potential therapeutic target for CRC.

Comprehensive analysis of epigenetic pattern of long noncoding RNA loci in colorectal cancer

Colorectal cancer (CRC) is one of the most common and severe cancers worldwide. The occurrence of CRC is developed by accumulation of genetic and epigenetic alteration in colon cells. Work over the last decade has proposed that epigenetic changes such as DNA methylation, histone modification of protein coding genes play an important role in CRC development. However, the epigenetic pattern and features of lncRNAs in CRC were unclear. Here, we comprehensively analyze the patterns of DNA methylation, H3K4me3, H3K27me3 on both protein coding genes and lncRNAs. We found several interesting results which may help to discriminate the lncRNAs from protein coding genes. For example, the signals of DNA methylation and H3K4me3 are higher on protein coding genes than lncRNAs, but not for H3K27me3; the three epigenetic marks show different distribution on promoters, termination and across the whole gene between protein coding genes and lncRNAs, especially DNA methylation, which show regular signal tendency according to the principle of gene transcription. In addition, we further analyzed the affections of epigenetic marks on protein coding gene and lncRNA expression in HCT116 colon cell. Most of the results were consistent with the previous reports such as H3K27me3 is an repressive mark. Furthermore, we analyzed the relationships among the three epigenetic marks and found that DNA methylation and H3K4me3 were positively correlated in promoter and termination region for both protein coding genes and lncRNAs. In a word, our results will give a clue to further study the pathologies of CRC.

Abstract C16: Serological biomarkers reflecting collagen remodeling of the tumor microenvironment are elevated in metastatic colorectal cancer patients

Abstract Background: The local microenvironment of a tumor plays an important role in colorectal cancer development. One of the hallmarks of colorectal cancer is abnormal remodeling of the extracellular matrix within the tumor microenvironment resulting in increased collagen deposition (desmoplasia) and increased matrix metalloproteinase (MMP) activity. This leads to the release of protein degradation fragments into the circulation. We investigated the potential of disease relevant fragments of collagen type I, III and IV as novel serological biomarkers for colorectal cancer. Methods: The level of biomarkers reflecting MMP-mediated degradation of type I (C1M), type III (C3M) and type IV (C4M) collagen and the formation of type III (Pro-C3) collagen were measured in serum from patients diagnosed with colorectal cancer (n=196, stage I-IV), subjects with adenomas (n=99, low risk-high risk) and age matched healthy controls (n=99). The levels of the individual biomarkers were compared using ANCOVA to adjust for age and gender on normalized data. Area under the receiver operating characteristics (AUROC) and logistic regression modeling were carried out to evaluate the discriminative power of the biomarkers. Results: Circulating levels of C1M, C3M and Pro-C3 were significantly elevated in colorectal cancer patients compared to subjects with adenomas (C1M and Pro-C3: p&amp;lt;0.0001, C3M: p&amp;lt;0.01) and healthy controls (C1M and Pro-C3: p&amp;lt;0.01, C3M: p&amp;lt;0.05). When patients were stratified according to their stage, all four biomarkers were able to differentiate stage IV patients from all other stages, adenomas and healthy controls (p&amp;lt;0.05-0.0001). Pro-C3 and C1M had the highest diagnostic accuracy in relation to identifying metastatic tumors from non-metastatic tumors with an AUROC of 0.80 and 0.78, respectively. When all biomarkers were combined the diagnostic power was improved (AUROC=0.85). Conclusion: In the present study we showed that specific serum biomarkers, reflecting collagen remodeling in the tumor microenvironment, could separate metastatic colorectal cancer patients from non-metastatic patients with high diagnostic power. This suggests that ECM remodeling is a key event in colorectal cancer development and biomarkers reflecting altered disease pathogenesis may increase the understanding of disease mode of action and provide a clinical tool for stratifying and monitoring patients according to disease severity. Citation Format: Stephanie Nina Kehlet, Rebeca Sanz-Pamplona, Diana Julie Leeming, Morten Asser Karsdal, Victor Moreno. Serological biomarkers reflecting collagen remodeling of the tumor microenvironment are elevated in metastatic colorectal cancer patients. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr C16.