Normal Colon Tissue Research Articles

Transcription factor forkhead box K1 regulates miR-32 expression and enhances cell proliferation in colorectal cancer.

Increased microRNA (miR)-32 expression in colorectal cancer (CRC) tissues enhances CRC cell proliferation, migration, invasion and attenuates CRC cell apoptosis by repressing the expression of phosphatase and tensin homolog (PTEN). Forkhead box K1 (FOXK1) was identified as a potential interacting transcription factor using DNA pull-down assays and mass spectrometry. The present study aimed to elucidate the role of FOXK1 in regulating miR-32 expression in CRC. The expressions of FOXK1, miR-32, transmembrane protein 245 gene (TMEM245) and PTEN were compared between CRC and normal colonic tissues. Levels of miR-32, TMEM245, PTEN and the proliferation and apoptosis of CRC cells were studied using FOXK1-overexpression or knockdown, or by simultaneously interfering with FOXK1 and miR-32 expression. Direct FOXK1 binding to the miR-32 promoter was verified using chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays. The results showed elevated FOXK1, miR-32 and TMEM245 expression, and significantly decreased PTEN expression in CRC, compared with normal colonic tissues. Correlations between the expressions of TMEM245 and miR-32, FOXK1 and miR-32, and FOXK1 and TMEM245 were positive and significant. FOXK1-knockdown led to decreased miR-32 and TMEM245 expression and increased PTEN expression, whereas FOXK1-overexpression had the opposite effect. Overexpressed FOXK1 promoted the malignancy of CRC cells in vitro by stimulating proliferation and reducing apoptosis; whereas FOXK1-depletion suppressed such malignancy and a miR-32 inhibitor partially reversed the effects of FOXK1. The results of ChIP and dual-luciferase reporter assays indicated that FOXK1 directly binds to the promoter of TMEM245/miR-32. Thus, the FOXK1-miR-32-PTEN signaling axis may play a crucial role in the pathogenesis and development of CRC.

GPR126 regulates colorectal cancer cell proliferation by mediating HDAC2 and GLI2 expression.

The G‐protein‐coupled receptor 126 (GPR126) may play an important role in tumor development, although its role remains poorly understood. We found that GPR126 had higher expression in most colorectal cancer cell lines than in normal colon epithelial cell lines, and higher expression levels in colorectal cancer tissues than in normal adjacent colon tissues. GPR126 knockdown induced by shRNA inhibited cell viability and colony formation in HT‐29, HCT116, and LoVo cells, decreased BrdU incorporation into newly synthesized proliferating HT‐29 cells, led to an arrest of cell cycle progression at the G1 phase in HCT‐116 and HT‐29 cells, and suppressed tumorigenesis of HT‐29, HCT116, and LoVo cells in nude mouse xenograft models. GPR126 knockdown engendered decreased transcription and translation of histone deacetylase 2 (HDAC2), previously implicated in the activation of GLI1 and GLI2 in the Hedgehog signaling pathway. Ectopic expression of HDAC2 in GPR126‐silenced cells restored cell viability and proliferation, GLI2 luciferase reporter activity, partially recovered GLI2 expression, and reduced the cell cycle arrest. HDAC2 regulated GLI2 expression and, along with GLI2, it bound to the PTCH1 promoter, as evidenced by a chip assay with HT‐29 cells. Purmorphamine, a hedgehog agonist, largely restored the cell viability and expression of GLI2 proteins in GPR126‐silenced HT‐29 cells, whereas GANT61, a hedgehog inhibitor, further enhanced the GPR126 knockdown‐induced inhibitory effects. Our findings demonstrate that GPR126 regulates colorectal cancer cell proliferation by mediating the expression of HDAC2 and GLI2, therefore it may represent a suitable therapeutic target for colorectal cancer treatment.

Immunohistochemical expression of \u03b2-catenin, Ki67, CD3 and CD18 in canine colorectal adenomas and adenocarcinomas

BackgroundInflammation is believed to influence human colorectal carcinogenesis and may have an impact on prognosis and survival. The mucosal immunophenotype in dogs with colorectal cancer is poorly described.The aim of this study was to investigate whether the density, distribution and grade of tumor-infiltrating immune cells (TIIs) are different in normal colonic tissue vs benign stages (adenomas) and malignant stages (adenocarcinomas) of canine colorectal carcinogenesis, and thus, whether they can be considered as prognostic factors in dogs.This retrospective case-control study was performed on formalin-fixed, paraffin-embedded tissue samples from dogs with histologically confirmed colorectal adenoma (n = 18) and adenocarcinoma (n = 13) collected from archived samples. The samples had been collected by colonoscopy, surgery or during postmortem examination. Healthy colonic tissue obtained post mortem from dogs euthanized for reasons not involving the gastrointestinal tract served as control tissue (n = 9).ResultsThe tumor samples had significantly lower numbers of CD3+ T-cells in the epithelium compared to controls (adenocarcinoma vs control, Kruskal-Wallis test, p = 0.0004, and adenoma vs control, p = 0.002). Adenomas had a significantly lower number of CD18+ cells in the lamina propria, compared to control samples (Kruskal-Wallis test, p = 0.008). Colonic samples from control dogs had uniform staining of β-catenin along the cell membrane of epithelial cells. Compared to normal colonic cells, the expression levels of cytoplasmic β-catenin were significantly higher in adenomas and adenocarcinomas (adenoma vs control Kruskal-Wallis test, p = 0.004, and adenocarcinoma vs control, p = 0.002). None of the control samples showed positive staining of β-catenin in the nucleus of colonic cells. In contrast, adenocarcinomas and adenomas showed moderate to strong staining of the cell nucleus. The nuclear β-catenin expression (signal strength and distribution) was significantly higher in adenomas compared to adenocarcinomas (Kruskal-Wallis test, p < 0.05).Conclusionsβ-catenin and Ki67 were not useful markers for demonstrating tumor progression from adenomas to adenocarcinomas. The lower presence of CD18 and CD3+ cells in colorectal tumors compared to controls indicates a reduced presence of histiocytes and T-cells, which may have implications for the pathogenesis and progression of colorectal cancer in dogs.

The cancer testis antigens CABYR-a/b and CABYR-c are expressed in a subset of colorectal cancers and hold promise as targets for specific immunotherapy.

Introduction: Calcium-binding tyrosine phosphorylation-regulated protein (CABYR) is expressed in the human germ line but not in adult human tissues, thus, it is considered a cancer testis protein. The aim of this study is to evaluate the CABYR isoforms: a/b and c mRNA expression in colorectal cancer (CRC) and to determine if these proteins hold promise as vaccine targets.Materials and Methods: CABYR mRNA expression in a set of normal human tissues, including the testis, were determined and compared using semi-quantitative PCR. As regards the tumor and normal mucosal samples from study patients, RNA was extracted and cDNA generated after which quantitative PCR was carried out. Analysis of CABYR protein expressions by immunohistochemistry in tumor and normal colon tissues was also performed.Results: A total of 47 paired CRC and normal tissue specimens were studied. The percent of patients with a relative expression ratio of malignant to normal (M/N) tissues over 1 was 70% for CABYR a/b and 72% for CABYR c. The percent with both a M/N ratio over 1 and expression levels over 0.1% of testis was 23.4% for CABYR-a/b and 25.5% for CABYR c. CABYR expression in tumors was further confirmed by immunohistochemistry.Conclusions: CABYR a/b and c hold promise as specific immunotherapy targets, however, a larger and more diverse group of tumors (Stage 1-4) needs to be assessed and evaluation of blood for anti-CABYR antibodies is needed to pursue this concept.

Integrated Bioinformatic Analysis of SARS-CoV-2 Infection Related Genes ACE2, BSG and TMPRSS2 in Aerodigestive Cancers.

BackgroundCancer patients are more vulnerable to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection than the general population, with lung epithelial cells or enterocytes being the main targets. However, the expressions of SARS-CoV-2 entry-related genes in aerodigestive cancers have not been fully elucidated.MethodsIn this study, the expressions of SARS-CoV-2 receptors and cofactors, including angiotensin I-converting enzyme 2 (ACE2), basigin (BSG) and transmembrane serine protease 2 (TMPRSS2), were comprehensively assessed. We compared BSG and TMPRSS2 expressions between aerodigestive cancers and matched normal tissues through Gene Expression Profiling Interactive Analysis 2 (GEPIA2). Furthermore, expressions in healthy colon tissues at different anatomical locations were explored using the Genotype-Tissue Expression (GTEx) dataset. In addition, expressions among different tumor stages and the prognostic values were detected through GEPIA2. Moreover, the correlation between gene expression and immune infiltration was explored via Tumor Immune Estimation Resource (TIMER). Finally, expressions in primary colorectal cancer (CRC), lung metastasis and liver metastasis were investigated using the Gene Expression Omnibus (GEO) dataset GSE41258.ResultsSimilar to ACE2, TMPRSS2 and BSG were also highly expressed in the digestive tracts. Intriguingly, BSG/TMPRSS2 expression in adjacent normal colon tissue or lung tissue was higher than that in corresponding healthy tissue, whereas they varied not among different tumor stages and correlated not with prognosis in aerodigestive cancers. Moreover, ACE2 was expressed at higher levels in lung metastases from CRC than in normal lung tissues.ConclusionSARS-CoV-2 entry genes were highly expressed in CRC, and we reported for the first time higher expression of ACE2 in lung metastases from CRC than in normal lung, indicating that these patients may be more susceptible to extrapulmonary or pulmonary SARS-CoV-2 infection. Since our study is a bioinformatic analysis, further experimental evidences and clinical data are urgently needed.

SK4 oncochannels regulate calcium entry and promote cell migration in KRAS-mutated colorectal cancer

BackgroundColorectal cancer (CRC) metastases are the main cause of CRC mortality. Intracellular Ca2+ regulates cell migration and invasion, key factors for metastases. Ca2+ also activates Ca2+-dependent potassium channels which in turn affect Ca2+ driving force. We have previously reported that the expression of the Ca2+ activated potassium channel KCNN4 (SK4) is higher in CRC primary tumors compared to normal tissues. Here, we aimed to investigate the role of SK4 in the physiology of CRC. ResultsSK4 protein expression is enhanced in CRC tissues compared to normal colon tissues, with a higher level of KCNN4 in CRC patients with KRAS mutations. At the cellular level, we found that SK4 regulates the membrane potential of HCT116 cells. We also found that its inhibition reduced store operated Ca2+ entry (SOCE) and constitutive Ca2+ entry (CCE), while reducing cell migration. We also found that the activity of SK4 is linked to resistance pathways such as KRAS mutation and the expression of NRF2 and HIF-1α. In addition, the pharmacological inhibition of SK4 reduced intracellular reactive oxygen species (ROS) production, NRF2 expression and HIF1α stabilization. ConclusionOur results suggest that SK4 contributes to colorectal cancer cell migration and invasion by modulating both Ca2+ entry and ROS regulation. Therefore, SK4 could be a potential target to reduce metastasis in KRAS-mutated CRC.

ELEVATED ADENOMATOUS POLYPOSIS COLI IN GOBLET CELLS IS ASSOCIATED WITH INFLAMMATION IN MOUSE AND HUMAN COLON

Adenomatous Polyposis Coli (APC) functions as an essential colon tumor suppressor. Roles for APC in other disease states such as Inflammatory Bowel Disease (IBD) remain less defined. In the process of characterizing Apc protein in gastrointestinal tissues from human patients with active IBD, we found a subset of goblet cells with elevated Apc staining intensity. While normal colon tissue was only sparsely populated with these “APChigh” goblet cells, tissue from patients with Ulcerative Colitis and Crohn’s Disease contained entire regions where almost every goblet cell was APChigh. In the descending colon, the APChigh goblet cells were prominent in patients with active Ulcerative Colitis but were mostly lacking in normal samples. In mice, APChigh cells were observed only in the small intestines and proximal/medial colons. Upon induction of colitis with Dextran Sodium Sulfate (DSS), the APChigh goblet cells remained in the proximal and medial colon, but also appeared in the distal colon. To better understand the link between APC expression, goblet cells, and inflammation, cultured human colon cells derived from normal tissue were depleted of APC and RNAseq analysis was performed. APC depletion resulted in reduced expression of mRNAs encoding IL1 signaling pathway components IL1b and IL1R, known regulators of Muc2 expression. Muc2 is the main constituent of goblet cell mucus, which is secreted to form a protective barrier for the epithelial cells lining the large intestine. We found that treating cancer cells lacking wild-type APC with IL1b resulted in increased IL1R and MUC2 expression. Induction of full-length APC in these cells led to a similar phenotype. Combining IL1β treatment with APC induction led to an increase of MUC2 expression greater than expected for additive affects, suggesting that APC sensitized these cells to IL1 signaling. These results illuminate a novel role for APC in goblet cells under conditions of inflammation. We postulate that the higher amount of APC in a subset of goblet cells might sensitize them to IL-1 signaling. During times of inflammation, such as active Ulcerative Colitis, goblet cells with higher APC levels would be more sensitive to IL-1-induced MUC2 expression than other goblet cells, perhaps protecting the intestinal lining from further barrier breaches.

CMTM6 and PD-L1 coexpression is associated with an active immune microenvironment and a favorable prognosis in colorectal cancer

BackgroundCKLF-like MARVEL transmembrane domain-containing 6 (CMTM6), a programmed death-ligand 1 (PD-L1) regulator, is widely expressed in various tumors and regulates the immune microenvironment. However, its prognostic value remains controversial, and...

The Importance of Sex in the Discovery of Colorectal Cancer Prognostic Biomarkers.

Colorectal cancer (CRC) is the third leading cause of cancer deaths. Advances within bioinformatics, such as machine learning, can improve biomarker discovery and ultimately improve CRC survival rates. There are clear sex differences in CRC characteristics, but the impact of sex has not been considered with regards to CRC biomarkers. Our aim here was to investigate sex differences in the transcriptome of a normal colon and CRC, and between paired normal and tumor tissue. Next, we attempted to identify CRC diagnostic and prognostic biomarkers and investigate if they are sex-specific. We collected paired normal and tumor tissue, performed RNA-seq, and applied feature selection in combination with machine learning to identify the top CRC diagnostic biomarkers. We used The Cancer Genome Atlas (TCGA) data to identify sex-specific CRC diagnostic biomarkers and performed an overall survival analysis to identify sex-specific prognostic biomarkers. We found transcriptomic sex differences in both the normal colon tissue and in CRC. Forty-four of the top-ranked biomarkers were sex-specific and 20 biomarkers showed a sex-specific prognostic value. Our data show the importance of sex in the discovery of CRC biomarkers. We propose 20 sex-specific CRC prognostic biomarkers, including ESM1, GUCA2A, and VWA2 for males and CLDN1 and FUT1 for females.

Metabolic Alteration in Plasma and Biopsies From Patients With IBD.

Inflammatory bowel diseases (IBD) are chronic inflammatory disorders of the gastrointestinal tract, with periods of latency alternating with phases of exacerbation, and include 2 forms: Crohn disease (CD) and ulcerative colitis (UC). Although the etiology of IBD is still unclear, the identification and understanding of pathophysiological mechanisms underlying IBD could reveal newly targeted intestinal alterations and determine therapeutic approaches. In this study, by using gas chromatography-mass spectrometry, we characterized plasma and biopsies from the metabolomics profiles of patients with IBD compared with those of a control group. The results showed a different metabolomics profile between patients with CD (n = 50) and patients with UC (n = 82) compared with the control group (n = 51). Multivariate statistical analysis of the identified metabolites in CD and UC showed changes in energetic metabolism, and lactic acid and ornithine in particular were altered in both plasma and colon biopsies. Moreover, metabolic changes were evidenced between the normal ileum and colon tissues. These differences disappeared when we compared the inflamed ileum and colon tissues, suggesting a common metabolism. This study showed how the metabolomics profile could be a potential tool to identify intestinal alterations associated with IBD and may have application in precision medicine and for better defining the pathogenesis of the disease.

Detection of colorectal cancer using a small molecular fluorescent probe targeted against c-Met

Colorectal cancer (CRC), a highly heterogeneous genetic disease, is currently the second leading cause of cancer-related deaths worldwide. This malignant cancer is typically preceded by the development of precancerous lesions, which are challenging to distinguish their subtle morphologic changes. Molecular-based fluorescence imaging can effectively identify lesion targets to enhance image contrast and improve the detection of early neoplasia comparing to conventional wide-light screening endoscopy. C-Met has been identified as overexpressed in CRC advanced stage and has been suggested as a validated potential theranostic target. Herein, we developed a new small molecular fluorescence probe, namely Crizotinib-PEG4-MPA, specifically binds to c-Met in CRC cells and colitis-associated cancer adenoma. In vitro binding studies confirmed the specificity and selectively of Crizotinib-PEG4-MPA against c-Met, the corresponding apparent equilibrium dissociation constants (Kd) was 3.86 μM for Crizotinib-PEG4-MPA. Additionally, the probe was carried out to c-Met positive tumor-bearing mice in vivo to explore the diagnostic potential clinical value, the method used a randomized block design to cluster mice into groups and found the tumor/normal signal ratio value up to 4.23 (95% confidence interval (CI) 4.07–4.39) at 6 h. More importantly, Crizotinib-PEG4-MPA was used to detect the occurrence of the colon adenoma and the in vivo imaging results showed the mean fluorescence intensity of the CAC colon is significantly higher than that in the normal group (P < 0.001). Furthermore, the immunofluorescence signals of biopsies samples demonstrated the probe indeed targets the c-Met and possesses the property to distinguish colon adenoma from normal colon tissue. Altogether, this novel fluorescence probe, with excellent C-met-targeting ability, has a substantial potential to serve as a widely available in vivo tracer for the early diagnosis and monitoring of colorectal cancer.

RNA binding protein PUM1 promotes colon cancer cell proliferation and migration

Colon cancer is the third leading cause of death worldwide and sixth in India, where it is the cause of 5.8% of the total deaths. Pumilio-1 (PUM1) is an RNA binding protein whose regulatory role is by binding to the consensus 5′UGUANAUA3′ sequence on the 3′UTR of the mRNA targets and post-transcriptionally repressing their expression. This study is the first of its kind to report the expression or function of PUM1 in colon cancer. We found that PUM1 mRNA expression is high in primary and metastatic colon cancer cell lines when compared to the normal colon cell line. Immunohistochemistry analysis showed similar trend wherein compared to the normal colon tissue, PUM1 was found to be overexpressed in both adenocarcinoma and in metastatic carcinoma. This confirms the role of PUM1 in colon cancer progression. PUM1 overexpression study in HCT116 revealed that cells transfected with PUM1 plasmid show an increased rate of proliferation, migration and colony formation. Overexpressing PUM1 increases the number and size of spheroids indicating the role of PUM1 in maintaining cancer stem cells. Overall, this is the first study that has shown the role of PUM1 in colon cancer development.

ELEVATED ADENOMATOUS POLYPOSIS COLI IN GOBLET CELLS IS ASSOCIATED WITH INFLAMMATION IN MOUSE AND HUMAN COLON

Abstract Adenomatous Polyposis Coli (APC) functions as an essential colon tumor suppressor. Roles for APC in other disease states such as Inflammatory Bowel Disease (IBD) remain less defined. In the process of characterizing Apc protein in gastrointestinal tissues from human patients with active IBD, we found a subset of goblet cells with elevated Apc staining intensity. While normal colon tissue was only sparsely populated with these “APChigh” goblet cells, tissue from patients with Ulcerative Colitis and Crohn’s Disease contained entire regions where almost every goblet cell was APChigh. In the descending colon, the APChigh goblet cells were prominent in patients with active Ulcerative Colitis but were mostly lacking in normal samples. In mice, APChigh cells were observed only in the small intestines and proximal/medial colons. Upon induction of colitis with Dextran Sodium Sulfate (DSS), the APChigh goblet cells remained in the proximal and medial colon, but also appeared in the distal colon. To better understand the link between APC expression, goblet cells, and inflammation, cultured human colon cells derived from normal tissue were depleted of APC and RNAseq analysis was performed. APC depletion resulted in reduced expression of mRNAs encoding IL1 signaling pathway components IL1b and IL1R, known regulators of Muc2 expression. Muc2 is the main constituent of goblet cell mucus, which is secreted to form a protective barrier for the epithelial cells lining the large intestine. We found that treating cancer cells lacking wild-type APC with IL1b resulted in increased IL1R and MUC2 expression. Induction of full-length APC in these cells led to a similar phenotype. Combining IL1β treatment with APC induction led to an increase of MUC2 expression greater than expected for additive affects, suggesting that APC sensitized these cells to IL1 signaling. These results illuminate a novel role for APC in goblet cells under conditions of inflammation. We postulate that the higher amount of APC in a subset of goblet cells might sensitize them to IL-1 signaling. During times of inflammation, such as active Ulcerative Colitis, goblet cells with higher APC levels would be more sensitive to IL-1-induced MUC2 expression than other goblet cells, perhaps protecting the intestinal lining from further barrier breaches.

Tumor-Infiltrating Lymphoid Cells in Colorectal Cancer Patients with Varying Disease Stages and Microsatellite Instability-High/Stable Tumors.

Immune checkpoint inhibition is an effective anti-cancer therapeutic approach but has shown limited efficacy in treating colorectal cancer (CRC) patients. Importantly, immune constituents of the tumor microenvironment (TME) can influence therapy response and cancer progression. We investigated the expression of immune checkpoints (ICs) on lymphoid populations within the CRC TME and compared with cells from normal colon tissues using samples from 50 patients with varying disease stages. We found that the levels of B cells, T cells, and NK cells were similar, IC-expressing CD4+ and CD4+CD8+ double positive T cells were higher, while CD8+ T cells and CD4−CD8− double negative T cells were significantly lower in CRC tumors. Notably, patients with mismatch-repair deficiency/microsatellite instability-high tumors had higher levels of IC-expressing CD4+ and CD8+ T cells than patients with proficient MMR and microsatellite stable tumors. Lastly, The Cancer Genome Atlas Colon Adenocarcinoma datasets showed associations between low expression of selective genes and poorer progression-free interval. Our findings highlight differential expression of ICs on lymphoid cells in CRC tumors in the era of cancer immunotherapy, which at present is solely approved for anti-PD-1 therapy in patients with dMMR/MSI-H tumors. Further investigations into their functionality have potentials for deciphering resistance mechanisms to IC inhibition.

S100P Expression via DNA Hypomethylation Promotes Cell Growth in the Sessile Serrated Adenoma/Polyp-Cancer Sequence

Background/Aims: Sessile serrated adenomas/polyps (SSA/Ps) are a putative precursor lesion of colon cancer. Although the relevance of DNA hypermethylation in the SSA/P-cancer sequence is well documented, the role of DNA hypomethylation is unknown. We investigated the biological relevance of DNA hypomethylation in the SSA/P-cancer sequence by using 3-dimensional organoids of SSA/P. Methods: We first analyzed hypomethylated genes using datasets from our previous DNA methylation array analysis on 7 SSA/P and 2 cancer in SSA/P specimens. Expression levels of hypomethylated genes in SSA/P specimens were determined by RT-PCR and immunohistochemistry. We established 3-dimensional SSA/P organoids and performed knockdown experiments using a lentiviral shRNA vector. DNA hypomethylation at CpG sites of the gene was quantitated by MassARRAY analysis. Results: The mean number of hypomethylated genes in SSA/P and cancer in SSA/P was 41.6 ± 27.5 and 214 ± 19.8, respectively, showing a stepwise increment in hypomethylation during the SSA/P-cancer sequence. S100P, S100α2, PKP3, and MUC2 were most commonly hypomethylated in SSA/P specimens. The mRNA and protein expression levels of S100P, S100α2, and MUC2 were significantly elevated in SSA/P compared with normal colon tissues, as revealed by RT-PCR and immunohistochemistry, respectively. Among these, mRNA and protein levels were highest for S100P. Knockdown of the S100P gene using a lentiviral shRNA vector in 3-dimensional SSA/P organoids inhibited cell growth by >50% (p < 0.01). The mean diameter of SSA/P organoids with S100P gene knockdown was significantly smaller compared with control organoids. MassARRAY analysis of DNA hypomethylation in the S100P gene revealed significant hypomethylation at specific CpG sites in intron 1, exon 1, and the 5′-flanking promoter region. Conclusion: These results suggest that DNA hypomethylation, including S100P hypomethylation, is supposedly associated with the SSA/P-cancer sequence. S100P overexpression via DNA hypomethylation plays an important role in promoting cell growth in the SSA/P-cancer sequence.

Association between Streptococcus gallolyticus and colorectal cancer in Mansoura University hospitals

ABSTRACT Streptococcus gallolyticus (S. gallolyticus) bacteria are associated with colorectal cancer and adenoma. About 25–80% of patients with S. bovis bacteremia have concomitant colorectal tumors. This case control study aimed to detect the prevalence of S. gallolyticus in colorectal cancer tissues of patients attending Gastrointestinal Surgery Center (GISC) for colonoscopy, determine the correlation with the endoscopic finding and identify risk factors for acquisition of S. gallolyticus. Case samples were colorectal cancer tissue, obtained from 48 colorectal cancer patients who performed colonoscopy before administration of chemotherapy, control samples were normal colonic tissue taken from 48 persons who performed colonoscopy for any reason other than colorectal cancer. For isolation and identification of S. gallolyticus, the samples were processed, seeded on bile esculin agar, suspected colonies were identified with Gram staining, catalase, and pyrolidonyl arylamindase test. Age was significantly older in cases compared to controls. Both gender and residence did not significantly differ between the study groups. Occupational contact with animals was significantly higher in cases compared to control. The prevalence of S. gallolyticus in colorectal cancer tissues was 35.4%. S. gallolyticus on the surface was positive in 64.6% of cases, versus only 18.8% of controls. On univariate analysis, diarrhea was a significant risk factor for having surface S. gallolyticus. No significant risk factors for colonizing S. gallolyticus in tissue were identified. The early detection of S. gallolyticus in cases of colorectal adenomas might be of high value in screening high risk groups for colorectal cancer.

Evaluation of EZH2 and ERRα in colorectal carcinoma: an immunohistochemical study.

The combined immunohistochemical evaluation of EZH2 (enhancer of zeste homolog 2) and ERRα (estrogen-related receptor α), in relation to clinicopathological prognostic factors and patients' outcome, has not been performed yet in colorectal carcinoma (CRC). In order to achieve this aim, 120 samples were extracted; 60 cases of CRC; and 60 samples from normal colonic tissue. Our study showed that 63.3% and 38.3% of CRC cases reveal high EZH2 and high ERRα nuclear expression, respectively. 6.6% and 8.3% of normal colonic mucosa samples express low EZH2 and low ERRα nuclear expression, respectively. High EZH2 and high ERRα expression correlate with late tumor stages (p = 0.001 each), high grade (p = 0.001, p = 0.009 respectively), positive lymph node involvement (p = 0.001, p = 0.002 respectively) and larger tumor size (p = 0.001 each). There is a moderate highly statistically significant agreement (κ = 0.467, p = 0.001) between EZH2 and ERRα immunohistochemical expression. By Kaplan Meier analysis, high EZH2 and high ERRα show statistically significant shorter overall survival, and progression free survival than cases with low EZH2 and low ERRα immunohistochemical expression, respectively. Thus, EZH2 and ERRα might serve as potential promising prognostic markers in CRC.

Immunohistochemical Assessment of Transthyretin Association with Colorectal Adenocarcinoma.

To explore the association of transthyretin (TRR) with colorectal cancer (CRC) development and progression. This study was conducted on 12 normal colorectal tissue samples, 15 colorectal adenomas, and 39 colorectal adenocarcinoma tissue specimens. TTR expression was assessed by immunohistochemistry, and the results were correlated to clinicopathological characteristics of CRC patients. TTR staining was detected in 16.7% (2/12) of normal colon tissues, 46.7% (7/15) of colorectal adenomas, and 89.7% (35/39) of colorectal adenocarcinoma tissues. TTR staining scores in normal colon tissues, adenoma, and adenocarcinoma were 0.58, 2.27, and 5.40, respectively. G3 grade adenocarcinoma had a higher TTR staining score compared with G2 and G1 grades (8.40, p = 0.0009). Lower TTR expression was significantly associated with metastasis (p = 0.043). TTR expression is positively correlated with adenoma to CRC progression. Thus, TTR has the potential to serve as a predictive marker in CRC.

Unraveling the genomic landscape of colorectal cancer through mutational signatures.

Colorectal cancer, along with most other cancer types, is driven by somatic mutations. Characteristic patterns of somatic mutations, known as mutational signatures, arise as a result of the activities of different mutational processes. Mutational signatures have diverse origins, including exogenous and endogenous sources. In the case of colorectal cancer, the analysis of mutational signatures has elucidated specific signatures for classically associated DNA repair deficiencies, namely mismatch repair (leading to microsatellite instability), base excision repair (due to MUTYH or NTHL1 mutations), and polymerase proofreading (due to POLE and POLD1 exonuclease domain mutations). Additional signatures also play a role in colorectal cancer, including those related to normal aging and those associated with gut microbiota, as well as a number of signatures with unknown etiologies. This chapter provides an overview of the current knowledge of mutational signatures, with a focus on colorectal cancer and on the recently reported signatures in physiologically normal and inflammatory bowel disease-affected somatic colon tissues.

Long noncoding RNA SH3PXD2A-AS1 promotes colorectal cancer progression by regulating p53-mediated gene transcription.

Long non-coding RNAs (lncRNAs) play key roles in various human cancers. We aimed to determine the key lncRNAs mediating colorectal cancer (CRC) progression. We identified some lncRNAs aberrantly expressed in CRC tissues by using lncRNA microarrays and demonstrated that SH3PXD2A-AS1 was one of the most highly overexpressed lncRNAs in CRC. We further aimed to explore the roles and possible molecular mechanisms of SH3PXD2A-AS1 in CRC. RNA ISH revealed that SH3PXD2A-AS1 was overexpressed in CRC compared with adjacent normal colon tissues and indicated poor prognosis in CRC. Functional analyses showed that SH3PXD2A-AS1 enhanced cell proliferation, angiogenesis, and metastasis. Mechanistically, SH3PXD2A-AS1 can directly interact with p53 protein and regulate p53-mediated gene transcription in CRC. We provided mechanistic insights into the regulation of SH3PXD2A-AS1 on p53-mediated gene transcription and suggested its potential as a new prognostic biomarker and target for the clinical management of CRC.