Tissues Of Colorectal Cancer Patients Research Articles

Differential Expression of miR-21, miR-23a, and miR-27a, and Their Diagnostic Significance in Egyptian Colorectal Cancer Patients.

Background: Colorectal cancer (CRC) rates are affected by genetics, ethnicity, and environmental factors; it is considered one of the most aggressive human malignancies with high mortality and morbidity rates worldwide due, in part, to its asymptomatic nature during the early stages of disease. Objective: Owing to the impact of microRNA (miRNA) dysregulation on CRC development and progression, this study was conducted to explore the expression levels of mir-21, -23a, and -27a in the sera and tissues of Egyptian CRC patients and to evaluate their diagnostic efficacy based on circulating levels. Methods: In the test phase, the relative expression levels of the studied miRNAs were evaluated in the sera of 70 participants (35 CRC patients and 35 healthy controls) using quantitative real-time-polymerase chain reaction and to verify their diagnostic value. The exploratory phase was designed to validate the tumor-derived trait by comparing the miRNA levels in the cancerous and adjacent noncancerous tissues. Results: The relative expression levels of the studied miRNAs were significantly upregulated in both serum and tumor tissues of the patients compared to their corresponding controls. In addition, significant positive correlations were found between the relative expression levels of the studied miRNAs in serum samples and their levels in the matched CRC tissues. The serum expression levels of mir-21 and -23a were more predictive of CRC than mir-27a. Conclusion: Circulating mir-21, -23a, and -27a expression levels appear to be valuable diagnostic biomarkers for CRC, especially when combined.

Evolution of Mutational Landscape and Tumor Immune-Microenvironment in Liver Oligo-Metastatic Colorectal Cancer.

Simple SummaryAbout 10% of colorectal cancer patients presents with oligo-metastatic disease. The aim of our study was to assess genetic and immunologic dynamics underlying the oligo-metastatic status, evaluating genotype-phenotype correlations in a clean and homogeneous clinical model of liver-limited metastatic colorectal cancer. We show that loss of KRAS and SMAD4 mutations characterizes the oligo-metastatic disease while a progressive mutational evolution (gain in KRAS, PI3KCA, BRAF and SMAD4) is observed in poly-metastatic evolving disease. Furthermore, high granzyme-B+ T-cells infiltration is found in oligo-metastatic lesions. This study can support innovative strategies to monitor clinical evolution and to induce regressive genetic trajectories in cancer.Genetic dynamics underlying cancer progression are largely unknown and several genes involved in highly prevalent illnesses (e.g., hypertension, obesity, and diabetes) strongly concur to cancer phenotype heterogeneity. To study genotype-phenotype relationships contributing to the mutational evolution of colorectal cancer (CRC) with a focus on liver metastases, we performed genome profiling on tumor tissues of CRC patients with liver metastatic disease and no co-morbidities. We studied 523 cancer-related genes and tumor-immune microenvironment characteristics in primary and matched metastatic tissues. We observed a loss of KRAS and SMAD4 alterations and a high granzyme-B+ T-cell infiltration when the disease did not progress. Conversely, gain in KRAS, PIK3CA and SMAD4 alterations and scarce granzyme-B+ T-cells infiltration were observed when the tumor evolved towards a poly-metastatic spread. These findings provide novel insights into the identification of tumor oligo-metastatic status, indicating that some genes are on a boundary line between these two clinical settings (oligo- vs. poly-metastatic CRC). We speculate that the identification of these genes and modification of their evolution could be a new approach for anti-cancer therapeutic strategies.

LncRNA LINC01116 Promotes the Development of Colorectal Cancer by Targeting miR-9-5p/STMN1.

PurposeThe aim was to research the role of LINC01116 in the prognosis of colorectal cancer (CRC) patients and development of colorectal cancer cells.MethodsIn total 62 colorectal cancer patient tissues and human CRC cell lines (OUMS23, SW116, SW480 and LOVO) were obtained for this study. SiLINC01116, miR-9-5p mimic, LINC01116, oe-STMN1 and their controls were transfected. The qRT-PCR method and Western blot were used to detect the levels of LINC01116, miR-9-5p and STMN1 in tissues and cells. CCK8 assay and flow cytometry were processed for proliferation and apoptosis, respectively. Transwell assay was undertaken to verify invasion and migration. Luciferase assay and pull down assay were processed to confirm the binding relationship among LINC01116, miR-9-5p and STMN1. Immunohistochemistry assay also detected the expression of STMN1. Kaplan–Meier survival curve was used to analyze patient survival rate. Pearson correlation analysis was used to evaluate the regulatory relationship between LINC01116, miR-9-5p and STMN1 in tissues.ResultsLINC01116 was expressed higher in CRC tissues and cells. Patients with higher expression of LINC01116 had worse prognosis. Knockdown of LINC01116 suppressed development of CRC cell. LINC01116 negatively regulated miR-9-5p, while MiR-9-5p was negatively related to STMN1. miR-9-5p mimic could rescue the effect of LINC01116, inhibit migration and invasion, and improve apoptosis of CRC cells. Oe-STMN1 could also rescue the effect of miR-9-5p on the development of colorectal cancer.ConclusionLINC01116 promoted the development of colorectal cancer via modulating miR-9-5p/STMN1 axis.

Quantitative evaluation of MSI testing using NGS detects the imperceptible microsatellite changed caused by MSH6 deficiency.

Microsatellite instability (MSI) is an effective biomarker for diagnosing Lynch syndrome (LS) and predicting the responsiveness of cancer therapy. MSI testing is conventionally performed by capillary electrophoresis, and MSI status is judged by visual assessment of allele size change. Here, we attempted to develop a quantitative evaluation model of MSI using next-generation sequencing (NGS). Microsatellite markers were analyzed in tumor and non-tumor tissues of colorectal cancer patients by NGS after a single multiplex polymerase chain reaction amplification. The read counts corresponding to microsatellite loci lengths were calculated independently of mapping against a reference genome, and their distribution was digitized by weighted mean. Weighted mean differences between tumor and non-tumor samples with different MSI status were assessed, and cut-off values for each marker in the discovery cohort were determined. Each microsatellite maker was defined as unstable if the weighted mean difference was greater than the cut-off value. In the discovery cohort, the evaluation model demonstrated sensitivity and specificity of 100% for all markers. In the validation cohort, MSI status determined by the new model was consistent with the outcome of the conventional method in 29/30 cases (97%). The single inconsistent case was classified as low-frequency MSI by the conventional method but considered MSI-high by NGS. Genetic testing for mismatch repair genes revealed a pathogenic variant in MSH6 in the discordant case. We successfully developed a quantitative evaluation method for determining MSI status using NGS. This is a robust and sensitive method and could improve LS diagnosis.

Potential Role of PDGFRβ-Associated THBS4 in Colorectal Cancer Development.

Simple SummaryWe found increased levels of THBS4 and PDGFRb in tumor tissues compared to normal tissues of colon cancer patients. The relationship and the cause of the increase in these proteins had to be determined. Therefore, we performed several experiments and confirmed that excessive PDGFRb stimulation induces the THBS4 secretion through the intracellular Ca2+ signaling proteins. Our data show the possibility of post-translational modification of THBS4 by PDGFRb stimulation as there was no significant change in the THBS4 mRNA.Colorectal cancer is a significant cause of death since it frequently metastasizes to several organs such as the lung or liver. Tumor development is affected by various factors, including a tumor microenvironment, which may be an essential factor that leads to tumor growth, proliferation, invasion, and metastasis. In the tumor microenvironment, abnormal changes in various growth factors, enzymes, and cytokines can wield a strong influence on cancer. Thrombospondin-4 (THBS4), which is an extracellular matrix protein, also plays essential roles in the tumor microenvironment and mediates angiogenesis by transforming growth factor-β (TGFβ) signaling. Platelet-derived growth factor receptor β (PDGFRβ), which is a receptor tyrosine kinase and is also a downstream signal of TGFβ, is associated with invasion and metastasis in colorectal cancer. We identified that PDGFRβ and THBS4 are overexpressed in tumor tissues of colorectal cancer patients, and that PDGF-D expression increased after TGFβ treatment in the colon cancer cell line DLD-1. TGFβ and PDGF-D increased cellular THBS4 protein levels and secretion but did not increase THBS4 mRNA levels. This response was further confirmed by the inositol 1,4,5-triphosphate receptor (IP3R) and stromal interaction molecule 1 (STIM1) blockade as well as the PDGFRβ blockade. We propose that the PDGFRβ signal leads to a modification of the incomplete form of THBS4 to its complete form through IP3R, STIM1, and Ca2+-signal proteins, which further induces THBS4 secretion. Additionally, we identified that DLD-1 cell-conditioned medium stimulated with PDGF-D promotes adhesion, migration, and proliferation of colon myofibroblast CCD-18co cells, and this effect was intensified in the presence of thrombin. These findings suggest that excessive PDGFRβ signaling due to increased TGFβ and PDGF-D in colorectal tumors leads to over-secretion of THBS4 and proliferative tumor development.

The relationship between KRAS gene mutation and intestinal flora in tumor tissues of colorectal cancer patients.

BackgroundColorectal cancer is among the most prominent malignant tumors endangering human health, with affected populations exhibiting an increasingly younger trend. The Kirsten ras (KRAS) gene acts as a crucial regulator in this disease and influences multiple signaling pathways. In the present study, the KRAS gene mutation-induced alteration of intestinal flora in colorectal cancer patients was explored, and the intestinal microbes that may be affected by the KRAS gene were examined to provide new insights into the diagnosis and treatment of colorectal cancer.MethodsDeoxyribonucleic acid (DNA) was extracted from 177 colorectal cancer patients in our hospital. The mutation of the KRAS gene was subsequently detected using real-time fluorescence quantitative polymerase chain reaction (qPCR), and survival analysis was performed. Moreover, genomic DNA was extracted from the fecal microbes in 30 of these patients, and the differences in the intestinal flora between mutation and non-mutation groups were evaluated using linear discriminant analysis (LDA) Effect size (LEfSe) analysis.ResultsKRAS gene mutation substantially affected the distant metastasis of colorectal cancer, and the survival prognosis in the non-mutation group was significantly superior compared to the mutation group. The mutation group had a notably higher prevalence of microbes including Roseburia, Parabacteroides, Metascardovia, Staphylococcus, Staphylococcaceae, and Bacillales than the non-mutation group. The presence of microbes in the non-mutation group, such as Clostridiales, Bacteroidetes, Lachnospiraceae, Coprococcus, and Ruminococcaceae was markedly higher than in the mutation group. Firmicutes were negatively correlated with the presence of Actinomyces and Bacteroidetes, while Bacteroidetes were positively associated with the level of Actinomyces.ConclusionsIn colorectal cancer, KRAS gene mutation can remarkably affect the survival prognosis and change the composition and abundance of intestinal flora, such as Roseburia, Parabacteroides, Metascardovia, Staphylococcus, and Bacillales, thereby influencing tumor development.

Comprehensive ceRNA network analysis and experimental studies identify an IGF2-AS/miR-150/IGF2 regulatory axis in colorectal cancer

Recently, a growing body of studies has demonstrated that long non-coding RNA (lncRNA) can act as microRNA (miRNA) sponges to regulate protein-coding gene expression and play essential roles in tumor initiation and progression. In the present study, we constructed a competitive endogenous RNA (ceRNA) network and identified potential regulatory axes in colorectal cancer (CRC) through both bioinformation and experimental validation. Firstly, we obtained differentially expressed (DE) lncRNAs, miRNAs, and mRNAs by analyzing the RNA expression profiles of CRC retrieved from The Cancer Genome Atlas (TCGA) database and CRC patients' data from affiliated Hospital of Jiangnan University, respectively. Then, we established a ceRNA regulatory network of CRC that includes 23 lncRNAs, 7 miRNAs and 244 mRNAs. To further identify these lncRNA-miRNA-mRNA regulatory axes which might play vital roles in CRC tumorigenesis and prognosis, we performed additional analyses using comprehensive bioinformatic methods. Several ceRNA regulatory axes, which consist of 2 lncRNAs, 2 miRNAs and 5 mRNAs, were obtained from the network. Finally, the interactions and correlations among these ceRNA networks were validated by experiments on CRC cell lines and clinical tumor tissues, and a potential IGF2-AS/miR-150/IGF2 axis that perfectly conform to the ceRNA theory was determined. According to the qRT-PCR results, miR-150 overexpression remarkably decreased IGF2-AS and IGF2 expression. Meanwhile, IGF2-AS expression was positively correlated with IGF2 expression in tumor tissue of CRC patients. Besides, dual luciferase reporter assays indicated that miR-150 could bound to IGF2-AS and the 3′UTR of and IGF2. In general, the constructed novel IGF2-AS/miR-150/IGF2 network might provide potential mechanisms of CRC development, and could act as a promising target for CRC treatment.

Increasing the expression of programmed death ligand 2 (PD-L2) but not 4-1BB ligand in colorectal cancer cells.

Immune checkpoint (ICP) molecules modulate the immune response by either inducing or preventing T cell activation. Over-expression of some ICPs on malignant cells has been shown to regulate anti-tumor immune responses. We aimed to investigate the expression levels of two immune checkpoint molecules which have not been studied extensively in patients with colorectal cancer (CRC). Programmed Death Ligand 2 (co-inhibitory) and 4-1BB ligand (co-stimulatory) were assessed in tumor tissues of CRC patients compared to the adjacent normal tissues. Following tissue excision during surgical operation from 21 CRC patients, RNA extraction, cDNA synthesis and semi-quantitative real-time PCR were done for measuring the expressions of PD-L2 and 4-1BBL genes. In protein level, indirect immunohistochemistery (IHC) was performed on tissue sections. We revealed that PD-L2 was expressed in about 81% CRCs and insignificantly correlated with the tumor differentiation grade. Although a 3.25-fold change in the gene expression of PD-L2 was found in tumor tissues compared to the adjacent normal tissues (P = 0.005), but decreased level of 4-1BBL in counterpart tissues was not significant. Our results were confirmed by IHC for PDL-2 (P = 0.02) and 4-1BBL, however it was not statistically significant for the latter one. Although not significant, we could find an association between the elevated expression of PD-L2 and the tumor differentiation grade. Increased expression of negative regulator of the anti-tumor immune responses like PD-L2, as a prominent way of tumor escape, can be considered for cancer immunotherapy approaches in CRC patients using blocking monoclonal antibodies.

Plastin 1 drives metastasis of colorectal cancer through the IQGAP1/Rac1/ERK pathway.

Tumor metastasis is the dominant cause of death in colorectal cancer (CRC) patients, and it often involves dysregulation of various cytoskeletal proteins. Plastin 1 (PLS1) is an actin‐bundling protein that has been implicated in the structure of intestinal epithelial microvilli; however, its role in CRC metastasis has not yet been determined. In this study, we demonstrated that PLS1 is highly expressed in 33.3% (45/135) of CRC patients and is correlated with lymph node metastasis and poor survival. In in vitro and in vivo experiments, PLS1 induced the migration and invasion of CRC cells and the metastases to the liver and lung in mice. Moreover, the expressions of key factors for CRC metastases, matrix metalloproteinase (MMP) 9 and 2, were enhanced by PLS1, which was dependent on phosphorylating ERK1/2 activated by IQGAP1/Rac1 signaling. The connection between these signals and PLS1 was further confirmed in CRC tissues of patients and the metastatic nodules from a mouse model. These findings suggest that PLS1 promotes CRC metastasis through the IQGAP1/Rac1/ERK pathway. Targeting PLS1 may provide a potential approach to inhibit the metastasis of CRC cells.

LINC00657 promotes colorectal cancer stem-like cell invasion by functioning as a miR-203a sponge

Recently, the role of long non-coding RNAs (lncRNAs) in regulating multiple cancer types has attracted increasing interest because of their involvement in cell metastasis in different cancer types. Previous studies indicated that LINC00657 may work as an oncogene in gastric and colon cancer. However, the functional role and mechanistic action of LINC00657 on colorectal cancer (CRC) remains unknown. Therefore, in this study, the role of LINC00657 in CRC was evaluated. Our results showed that LINC00657 was enriched in CRC stem-like cells (CSCs) and significantly promoted CSCs invasion ability. LINC00657 expression resulted frequently up-regulated in CRC patient tissue, and high expression of LINC00657 was correlated with an advanced clinical stage, lymph node metastasis, distant metastasis and poor overall survival of CRC patients. Furthermore, LINC00657 worked as a competing endogenous RNA (ceRNA) for miR-203a, antagonizing its function as a tumor suppressor and leading to the de-repression of CSCs invasion. Collectively, our observations revealed that LINC00657 is involved in CRC invasion by acting as a competing endogenous RNA. Thus, LINC00657 may serve as a potential prognostic factor and/or therapeutic target for CRC.

Th17 cells inhibit CD8+ T cell migration by systematically downregulating CXCR3 expression via IL-17A/STAT3 in advanced-stage colorectal cancer patients

BackgroundCD8+ T cell trafficking to the tumor site is essential for effective colorectal cancer (CRC) immunotherapy. However, the mechanism underlying CD8+ T cell infiltration in colorectal tumor tissues is not fully understood. In the present study, we investigated CD8+ T cell infiltration in CRC tissues and the role of chemokine–chemokine receptor signaling in regulation of T cell recruitment.MethodsWe screened chemokines and cytokines in healthy donor and CRC tissues from early- and advanced-stage patients using multiplex assays and PCR screening. We also utilized transcription factor activation profiling arrays and established a xenograft mouse model.ResultsCompared with tumor tissues of early-stage CRC patients, CD8+ T cell density was lower in advanced-stage tumor tissues. PCR screening showed that CXCL10 levels were significantly increased in advanced-stage tumor tissues. CXCR3 (the receptor of CXCL10) expression on CD8+ T cells was lower in the peripheral blood of advanced-stage patients. The migratory ability of CD8+ T cells to CXCL10 depended on CXCR3 expression. Multiplex arrays showed that IL-17A was increased in advanced-stage patient sera, which markedly downregulated CXCR3 expression via activating STAT3 signaling and reduced CD8+ T cell migration. Similar results were found after CD8+ T cells were treated with Th17 cell supernatant. Adding anti-IL-17A or the STAT3 inhibitor, Stattic, rescued these effects in vitro and in vivo. Moreover, survival analysis showed that patients with low CD8 and CXCR3 expression and high IL-17A levels had significantly worse prognosis.ConclusionsCD8+ T cell infiltration in advanced-stage tumor was systematically inhibited by Th17 cells via IL-17A/STAT3/CXCR3 axis. Our findings indicate that the T cell infiltration in the tumor microenvironment may be improved by inhibiting STAT3 signaling.

DNA methylation signatures predicting liver metastasis of colorectal cancer: A proof-of-concept pilot study.

e16080 Background: Liver metastasis (LIM) is the leading cause of death in colorectal cancer (CRC) patients. Early detection of LIM may improve outcome in CRC patients. The aim of this study was to evaluate the feasibility of predicting LIM of CRC using methylation profiles. Methods: We performed Roche targeted (~5.5 million methylation sites) bisulfite sequencing of matched primary, metastatic and their adjacent normal tissue samples from 5 CRC patients with LIM, 5 patients with lung metastasis (LUM) and 8 patients without metastasis in the training cohort (n = 48 samples). Differential methylation regions (DMR) of LUM were identified and a predictive model was developed. The model was further validated in primary tumor sample from nine patients (6 with LIM). Results: By comparing primary tumor vs adjacent normal tissues and metastatic tumor vs adjacent normal tissues in CRC patients with LIM, we identified 28954 common DMRs which indicating the methylation characteristic of CRC with LIM. Similarly, 16187 DMRs were identified in patients with LUM. 9179 DMRs are shared in both LIM and LUM comparisons which should be the common characteristic of CRC tumor tissue regardless of the location of metastasis. 7008 DMRs are LUM specific and 19775 DMRs are LIM specific. In order to predict LIM in primary, early changes in LIM specific DMRs should be identified. Hence, we further selected 4134 DMRs by chossing significantly differentically methylated regions between LIM primary tissues and LUM primary tissues. To increase the ability of distinguishing LIM from other normal tissues and non-matastasis CRC tumors, 1215 DMRs were finally selected which also showed increasing or decreasing trend of methylation level through the progression of CRC. The final 1215 biomarkers were used to construct a random forest model using methlylation profile of 5 CRC patients with LIM as positive training data and 5 CRC patients with LUM as well as 8 patients without metastasis as negative training data. Through the feature recursive elimination method, one methylation site (chr8.72468901-72469000) was identified with ROC of 0.9 in the training dataset. The predictive model was validated in an independent dataset which is composed of 6 patients with LIM and 3 patients without metastasis, and achieved an AUC of 0.87. Conclusions: Our findings demonstrate the utility of methylation biomarkers for the molecular characterization of metastatic precursors, with implications for prediction and early detection of liver metastasis in CRC.

Copy number variation and expression of CT-genes in patients with colorectal cancer.

e16104 Background: Cancer-testis antigens (CTAs) can be used for immunotherapeutic approaches and early detection of malignant tumors. Despite numerous studies of CTA expression in various tumors, including colon tumors, the mechanisms of transcriptional activity regulation in colorectal cancer (CRC) remain poorly studied. One of the possible mechanisms of regulation of gene expression is a change in their copy number (CNV). The aim of the study was to analyze the changes in the copy number and expression of CT-genes in patients with CRC. Methods: Tumor and normal colon tissues of 81 patients were used in the study. DNA was isolated by phenol-chloroform extraction. RNA was isolated by the Chomczynski&Sacchi method (2006). The REVERTA-L reagent kit was used for the cDNA synthesis. Determination of expression and copy number of 16 CT genes ( MAGE-A1, -A2, -A3, -A4, MAGE-B1, -B2, GAGE-1, -3, -4, MAGEC1, BAGE, XAGE3, NYESO1, SSX2, SCP1, PRAME1) was performed using the Real-Time qPCR method (reference genes - GAPDH and GUSB). Differences were evaluated using the Mann-Whitney test, correlation analysis - using Spearman's rank correlation coefficient (r). Results: An analysis of CT-gene expression and CNV in tumor and normal colon tissues (n = 81) revealed a statistically significant (p < 0.05) difference between these parameters in tumor tissue relative to normal one: for MAGEB1 an increase of 2.0 and 2.7 times, GAGE3 an increase of 2.0 and 2.5 times, GAGE4 decreased by 5.0 and 6.8 times, BAGE decreased by 2.4 and 1.7 times, SSX2 increased by 1.8 and 2.1 times, SCP1 increased copy number by 4.4 times and PRAME1 increased expression and copy number by 2.9 and 2.3 times, respectively. When comparing CNV and expression of 16 CT genes, a positive correlation was observed (r = 0.875). Conclusions: Thus, the aberrant expression of MAGEB1, GAGE3, GAGE4, BAGE, SSX2 and PRAME1 found in the tumor tissue of CRC patients depends on the copy number of these CT-genes.

Differential expression of micro-RNA in tumor and non-tumor tissues of patients with colorectal cancer.

e13516 Background: The colorectal cancer (CRC) incidence is steadily increasing. Moreover, the problem of its early diagnosis remains unresolved due to the low specificity of known tumor markers, and the problem of creating new therapeutic approaches is due to the lack of a complete understanding of the mechanisms of regulation of gene expression in this oncopathology. The study of micro-RNAs (short non-coding RNAs that regulate gene expression) can be the solution to both problems. The aim of the study was to analyze micro-RNA differential expression in the tumor and non-tumor tissues of CRC patients. Methods: 5 patients with CRC (colon adenocarcinoma, G2) were selected for the multiple parallel micro-RNA sequencing. The mirVana miRNA Isolation Kit protocol was used to isolate small RNA fractions. The miRNA library was prepared using the TruSeq Small RNASample Preparation Kit. Sequencing of the nucleotide sequences of cDNA libraries was performed using a MiSeq (Illumina, USA). The copy numbers of micro-RNA were determined by comparing the nucleotide sequence of the sequenced molecules in each sample with the known nucleotide sequences of micro-RNA presented in the databases. When analyzing the differential expression of micro-RNA, the DESeq2 method implemented in R medium was used. Results: Six differentially expressed micro-RNAs were detected (p < 0.05): 2 that decrease expression (hsa-miR-143-3p,hsa-miR-26a-5p) and 4 increase expression in the tumor relative to non-tumor (hsa-miR-25-3p, hsa-miR-92a-3p, hsa-miR-21-5p, hsa-let-7i-5p). The highest level of expression in both tumor and non-tumor tissue was observed for hsa-miR-143-3p, the lowest one for hsa-let-7i-5p. Moreover, the largest difference in micro-RNA expression in tumor tissue relative to non-tumor was shown for hsa-miR-92a-3p (4.5 times, p = 0.02), the smallest for hsa-miR-143-3p (2.4 times, p = 0.04). For miRNAs that differentially changed their expression, a search was made for target genes using the miRWalk 3.0 database. 14573 target genes were found, of which 3346 were for hypo-expressed micro-RNAs and 11228 for hyper-expressed micro-RNAs. Conclusions: Sequencing revealed 6 differentially expressed micro-RNAs (hsa-miR-143-3p, hsa-miR-26a-5p, hsa-miR-25-3p, hsa-miR-92a-3p, hsa-miR-21-5p, hsa-let-7i-5p) in the tumor tissue is relatively non-tumor tissues of the colon. The data obtained expand the understanding of the mechanisms of gene regulation in the context of this oncopathology and may possibly become the basis for highly specific tumor markers panel.

Metabolomics profiling of visceral and abdominal subcutaneous adipose tissue in colorectal cancer patients: results from the ColoCare study.

Underlying mechanisms of the relationship between body fatness and colorectal cancer remain unclear. This study investigated associations of circulating metabolites with visceral (VFA), abdominal subcutaneous (SFA), and total fat area (TFA) in colorectal cancer patients. Pre-surgery plasma samples from 212 patients (stage I-IV) from the ColoCare Study were used to perform targeted metabolomics. VFA, SFA, and TFA were quantified by computed tomography scans. Partial correlation and linear regression analyses of VFA, SFA, and TFA with metabolites were computed and corrected for multiple testing. Cox proportional hazards were used to assess 2-year survival. In patients with metastatic tumors, SFA and TFA were statistically significantly inversely associated with 16 glycerophospholipids (SFA: pFDR range 0.017-0.049; TFA: pFDR range 0.029-0.048), while VFA was not. Doubling of ten of the aforementioned glycerophospholipids was associated with increased risk of death in patients with metastatic tumors, but not in patients with non-metastatic tumors (phet range: 0.00044-0.049). Doubling of PC ae C34:0 was associated with ninefold increased risk of death in metastatic tumors (Hazard Ratio [HR], 9.05; 95% confidence interval [CI] 2.17-37.80); an inverse association was observed in non-metastatic tumors (HR 0.17; 95% CI 0.04-0.87; phet = 0.00044). These data provide initial evidence that glycerophospholipids in metastatic colorectal cancer are uniquely associated with subcutaneous adiposity, and may impact overall survival.

Expression of immune checkpoints and T cell exhaustion markers in early and advanced stages of colorectal cancer

Despite recent advances in colorectal cancer (CRC) treatment, a large proportion of patients show limited responses to therapies, especially in advanced stages. There is an urgent need to identify prognostic biomarkers and/or therapeutic targets in advanced stages, aiming to improve the efficacy of current treatments. We aimed to determine prognostic biomarkers in tumor tissue and circulation of CRC patients, with a special focus on T cell exhaustion markers. We found that mRNA levels of PD-1, TIM-3, CTLA-4, TIGIT, CD160, CD244, KLRG1, TOX2, TOX3, Ki-67, and PRDM1 were elevated in CRC tumor tissues. We also investigated differences in gene expression between early and advanced disease stages. We found that TOX and potentially TIM-3, CTLA-4, VISTA, TIGIT, KLRG1, TOX2, SIRT1, Ki-67, and Helios mRNA levels in tumor tissue were elevated in advanced disease stages, suggesting their potential roles in CRC progression. In contrast, PD-1 and CD160 levels in tumor tissue were downregulated in advanced stages. In the circulation of CRC patients, mRNA levels of PD-1, VISTA and LAG-3 were higher than those of healthy individuals. Moreover, in circulation, PD-1, CTLA-4 and TIGIT mRNA levels were reduced in advanced stages. Interestingly, levels of PD-1 in both tumor tissue and circulation were reduced in advanced stages, suggesting that targeting PD-1 in patients with advanced stages could be less effective. Altogether, these findings suggest some potential T cell exhaustion markers that could be utilized as prognostic biomarkers and/or therapeutic targets for CRC. However, further investigations and validations in larger cohorts are required to confirm these findings.

MicroRNA Binding Site Polymorphisms of the Long-Chain Noncoding RNA MALAT1 are Associated with Risk and Prognosis of Colorectal Cancer in Chinese Han Population

Background: The metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) gene's rs664589 locus is located within the binding site of the miRNA hsa-miR-194-5p for its cognate long-chain noncoding RNA (lncRNA) MALAT1. The aim of this study was to investigate the association between the rs664589 single nucleotide polymorphism (SNP) and the risk and prognosis of colorectal cancer (CRC) in the Chinese Han population. Methods: A cohort of 340 patients with CRC who underwent surgical resection and another group of 340 healthy subjects were enrolled in this study and analyzed for their rs664589 genotypes. In addition, quantitative real-time-polymerase chain reaction was used to detect the expression levels of the lncRNA MALAT1 and the hsa-miR-194-5p in cancer tissues and paracancerous normal tissues of CRC patients. Results: The risk of CRC in subjects carrying the G allele at the rs664589 locus in the 3' untranslated region of the MALAT1 gene was 1.81 times higher than for C allele carriers. The expression levels of the lncRNA MALAT1 in cancer tissues was significantly higher than that in paracancerous tissues, while the hsa-miR-194-5p expression level was significantly lower in cancerous tissues compared to cognate paracancerous tissues. The progression-free survival (PFS) rate for patients with the MALAT1 gene rs664589 locus GG genotype was significantly lower than that of CG genotype patients. Moreover, lncRNA MALAT1 inhibited the expression of hsa-miR-194-5p. Conclusion: The risk of CRC was relatively higher among MALAT1 rs664589 G allele carriers, and the CRC patients with a G allele had a lower PFS. The likely mechanism underlying these observations is that the rs664589 SNP affects the binding efficiency between the lncRNA MALAT1 and the miRNA has-miR-194-5p, although this awaits laboratory confirmation.

Tenascin-C predicts poor outcomes for patients with colorectal cancer and drives cancer stemness via Hedgehog signaling pathway

BackgroundTenascin-C (TNC) is an extracellular matrix protein that is widely expressed in the stromal fibroblasts of various cancers. However, the roles of TNC in colorectal cancer (CRC) cells remain unclear.MethodsThe expression of TNC, cancer stem cell-like (CSC) and cell cycle markers, and Hedgehog (HH) signaling pathway genes were assessed in 100 paraffin embedded clinical CRC patient tissues using immunohistochemistry. The interaction between TNC and CSC marker or HH related genes in CRC cells were detected by immunofluorescence. Cell cycle distribution was measured by flow cytometry. Migration and invasion were evaluated by transwell assays. The expressions of TNC, CSC marker, and HH related proteins were analyzed by western blot.ResultsTNC expression was markedly upregulated in CRC tissues, and was associated with worse clinical outcomes. TNC overexpression was positively associated with CSC marker LSD1, cell cycle markers CDK4 and p16, and HH signaling pathway related genes SMO and GLI1 in clinical CRC tissue samples. TNC silencing downregulated the expression of the CSC marker LSD1, and the proliferation, migration, and invasion of CRC cells. Interestingly, the GLI1 inhibitor GANT61 strongly inhibited the expression of TNC in CRC cells.ConclusionsTNC may drive tumor progression and is involved in CSC properties via the HH signaling pathway. TNC has potential value in the evaluation of poor prognosis in CRC.

Oxidative Damage in Sporadic Colorectal Cancer: Molecular Mapping of Base Excision Repair Glycosylases in Colorectal Cancer Patients.

Oxidative stress with subsequent premutagenic oxidative DNA damage has been implicated in colorectal carcinogenesis. The repair of oxidative DNA damage is initiated by lesion-specific DNA glycosylases (hOGG1, NTH1, MUTYH). The direct evidence of the role of oxidative DNA damage and its repair is proven by hereditary syndromes (MUTYH-associated polyposis, NTHL1-associated tumor syndrome), where germline mutations cause loss-of-function in glycosylases of base excision repair, thus enabling the accumulation of oxidative DNA damage and leading to the adenoma-colorectal cancer transition. Unrepaired oxidative DNA damage often results in G:C>T:A mutations in tumor suppressor genes and proto-oncogenes and widespread occurrence of chromosomal copy-neutral loss of heterozygosity. However, the situation is more complicated in complex and heterogeneous disease, such as sporadic colorectal cancer. Here we summarized our current knowledge of the role of oxidative DNA damage and its repair on the onset, prognosis and treatment of sporadic colorectal cancer. Molecular and histological tumor heterogeneity was considered. Our study has also suggested an additional important source of oxidative DNA damage due to intestinal dysbiosis. The roles of base excision repair glycosylases (hOGG1, MUTYH) in tumor and adjacent mucosa tissues of colorectal cancer patients, particularly in the interplay with other factors (especially microenvironment), deserve further attention. Base excision repair characteristics determined in colorectal cancer tissues reflect, rather, a disease prognosis. Finally, we discuss the role of DNA repair in the treatment of colon cancer, since acquired or inherited defects in DNA repair pathways can be effectively used in therapy.

LncRNA ST8SIA6-AS1 promotes colorectal cancer cell proliferation, migration and invasion by regulating the miR-5195/PCBP2 axis.

Long non-coding RNAs (lncRNAs) have been reported to play a vital role in the development and progression of various cancers, including colorectal cancer (CRC). Although the dysregulation of lncRNA ST8SIA6-AS1 participates in the development of multiple malignancies, the underlying molecular mechanisms of ST8SIA6-AS1 in regulating CRC progression remain to be fully discovered. The expression level of lncRNA ST8SIA6-AS1 was examined in the tumor tissues and paracancerous tissues of CRC patients. Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was utilized to examine the expression levels of ST8SIA6-AS1, miR-5195, and Poly-(C) Binding Protein 2 (PCBP2). The protein expression level of PCBP2 was detected by Western blotting. MTT assay was performed to measure the proliferation of HCT-116 and SW480 cells. Cell migration and invasion abilities were measured by transwell assay. Luciferase reporter assay was used to examine the interaction between miR-5195 and ST8SIA6-AS1 or PCBP2. This study revealed that lncRNA ST8SIA6-AS1 was upregulated in CRC tissues and cells. Knockdown of ST8SIA6-AS1 inhibited proliferation, migration, and invasion of CRC cells. Moreover, ST8SIA6-AS1 was proved to inhibit miR-5195 expression by directly targeting miR-5195. In addition, it was demonstrated that overexpression of miR-5195 inhibited CRC progression. Furthermore, PCBP2 was shown to enhance sh-ST8SIA6-AS1 and miR-5195 mimics-attenuated cell proliferation, migration, and invasion by directly binding to miR-5195. Our study revealed that ST8SIA6-AS1 promoted CRC progression via the miR-5195/PCBP2 axis. This study may provide an improved understanding of the pathogenesis of CRC.