Colorectal adenoma to carcinoma progression is accompanied by changes in gene expression associated with ageing, chromosomal instability, and fatty acid metabolism

Dietary silymarin supplementation enhances chemotherapy efficacy of capecitabine and irinotecan and mitigates hepatotoxicity in a mouse model of colon cancer

Background and purpose

The flavonoid silymarin (SMN) has shown promise due to its antioxidant, anti-inflammatory, and anticancer properties. SMN has been widely used in preclinical and clinical studies to treat various types of cancer, alone and with chemotherapy agents. Recent research suggests that SMN may increase conventional chemotherapy efficacy and reduce adverse effects. Herein, we investigated the therapeutic efficacy of SMN and its combination with capecitabine (CAP) and irinotecan (IRI) in a mouse model of colon cancer.

Experimental approach

Following 1,2 dimethylhydrazine-induced colon cancer, a modified diet supplemented with SMN (2500 ppm) and mono- and combined therapy of CAP and IRI was used. Serum samples were analyzed for lipid profile, liver function, and inflammatory cytokines. Oxidative stress and inflammation markers, including malondialdehyde (MDA), nitric oxide (NO), myeloperoxidase (MPO), superoxide dismutase (SOD), and glutathione peroxidase (GPx) were measured in colonic, hepatic, and circulatory samples. Colonic BAX and Bcl-2 levels were examined via western blotting and histopathological analysis of colon sections was conducted.

Findings/Results

SMN alone and combined with chemotherapeutic agents significantly mitigated the elevated inflammatory cytokines liver function enzyme levels, and hyperlipidemia. Furthermore, SMN supplementation with chemotherapy agents enhanced antioxidant activity and reduced lipid peroxidation and inflammatory markers. Significant upregulation of BAX and downregulation of Bcl-2 were observed. In addition, treatment regimens ameliorated carcinogen-induced polyp multiplicity, adenoma formation, dysplastic changes, and lymphocytic aggregation.

Conclusion and implications

Our results demonstrated that the potential anticancer properties of SMN could enhance chemotherapy efficacy and reduce carcinogen- and chemotherapy-induced hepatotoxicity.

Exploring the Mechanism of Canmei Formula in Preventing and Treating Recurrence of Colorectal Adenoma Based on Data Mining and Algorithm Prediction

BACKGROUND

The high incidence of recurrence and malignant transformation of colorectal adenoma (CRA) are current issues that need to be addressed in clinical practice. Canmei Formula (CMF) has shown promising results in the prevention and treatment, however, it lacks effective clinical data support and its mechanism of action is not fully elucidated.

OBJECTIVE

The aim of this study is to evaluate the clinical efficacy and safety of CMF in preventing and treating CRA, and to explore its effective chemical components and pharmacological mechanisms.

METHOD

A randomized controlled clinical trial was conducted, with patients diagnosed with CRA within 6 months as the study subjects. After randomization, the patients were divided into a treatment group (receiving CMF granules) or a control group (receiving berberine hydrochloride tablets). The one-year recurrence rate of CRA was used as the key efficacy indicator to assess the effectiveness of CMF in preventing and treating CRA. The chemical components of CMF were identified using the UFLC-Q-TOF-MS/MS combined system. Data mining and the wSDTNBI algorithm were combined to construct a differential expression gene (DEG) - CMF prediction target interaction network for CRA. The core targets of CMF in CRA prevention and treatment were identified through topological analysis, and validated using molecular docking and in vitro experiments.

RESULT

During the period from October 1 2021 to December 31 2023, a total of 228 participants were included in the study. After block randomization, 114 patients were assigned to each group. In the treatment group, 98 patients completed follow-up examinations, with 16 patients (14.0%) exhibiting shedding, Adenoma recurrence was identified in 24 (24.5%) patients through colonoscopy. In the control group, 99 cases completed the follow-up examination, while 15 cases (13.2%) were lost to follow-up. There were 45 cases (45.5%) experienced recurrence of adenomas. During the follow-up period, no cases of colorectal cancer or severe adverse reactions were reported. UFLC-QTOF-MS/MS identification was combined with traditional Chinese medicine database mining to obtain 192 active chemical components of Canmei Formula. Using the wSDTNBI algorithm, 1044 prediction targets were predicted, and 3308 differentially expressed genes of CRA were extracted from the TCGA database. Network topology analysis and bioinformatics analysis were performed on 164 intersecting core targets. Molecular docking and qPCR analysis revealed that CMF downregulates angiotensin II type 1 receptor (AT1R) and regulated interleukin-8 (CXCL8) and matrix metalloproteinase 13 (MMP13) within the REN/Ang II/AT1R axis of the renin-angiotensin signaling pathway, thereby preventing and treating CRA.

CONCLUSION

This small-scale randomized controlled clinical trial showed that CMF granules can safely and effectively reduce the risk of CRA recurrence. CMF prevents and treats colorectal adenomas by modulating the renin-angiotensin signaling pathway and the inflammatory response.

The Prognostic Impact of Adipophilin Expression on Long-Term Survival Following Liver Resection in Patients with Colorectal Liver Metastases

Background/Objectives: Adipophilin (ADP) is a protein associated with lipid droplets, and its expression is related to poor prognosis in certain cancers. However, its impact on the survival of patients with colorectal liver metastases (CRLMs) remains unclear. This study investigated the impact of ADP expression on long-term survival following hepatectomy in patients with CRLM. Methods: We retrospectively analyzed 102 consecutive patients who underwent hepatectomy between 2006 and 2022. ADP expression was examined in resected specimens through immunohistochemical staining using tissue microarrays. Long-term outcomes for ADP-positive (n = 51) and ADP-negative (n = 51) groups were compared with Kaplan-Meier survival analysis. Results: We found significantly decreased 5-year recurrence-free survival (RFS) and overall survival (OS) rates for ADP-positive patients relative to ADP-negative patients (29.4% versus 52.1%, respectively; p = 0.001 and 43.7% versus 72.2%, respectively; p = 0.003). Moreover, multivariate Cox hazards analysis demonstrated that patients with ADP-positive CRLM had a worse prognosis after hepatectomy than those with ADP-negative CRLM, as reflected by both RFS (HR 2.46, 95% CI 1.39-4.36, p = 0.002) and OS (HR: 2.89, 95% CI 1.43-5.85, p = 0.003). Conclusions: ADP expression had a significant prognostic impact on the survival of patients with CRLM following liver resection and may aid in optimal treatment planning.

Involvement of tumor immune microenvironment metabolic reprogramming in colorectal cancer progression, immune escape, and response to immunotherapy

Metabolic reprogramming is a k`ey hallmark of tumors, developed in response to hypoxia and nutrient deficiency during tumor progression. In both cancer and immune cells, there is a metabolic shift from oxidative phosphorylation (OXPHOS) to aerobic glycolysis, also known as the Warburg effect, which then leads to lactate acidification, increased lipid synthesis, and glutaminolysis. This reprogramming facilitates tumor immune evasion and, within the tumor microenvironment (TME), cancer and immune cells collaborate to create a suppressive tumor immune microenvironment (TIME). The growing interest in the metabolic reprogramming of the TME, particularly its significance in colorectal cancer (CRC)-one of the most prevalent cancers-has prompted us to explore this topic. CRC exhibits abnormal glycolysis, glutaminolysis, and increased lipid synthesis. Acidosis in CRC cells hampers the activity of anti-tumor immune cells and inhibits the phagocytosis of tumor-associated macrophages (TAMs), while nutrient deficiency promotes the development of regulatory T cells (Tregs) and M2-like macrophages. In CRC cells, activation of G-protein coupled receptor 81 (GPR81) signaling leads to overexpression of programmed death-ligand 1 (PD-L1) and reduces the antigen presentation capability of dendritic cells. Moreover, the genetic and epigenetic cell phenotype, along with the microbiota, significantly influence CRC metabolic reprogramming. Activating RAS mutations and overexpression of epidermal growth factor receptor (EGFR) occur in approximately 50% and 80% of patients, respectively, stimulating glycolysis and increasing levels of hypoxia-inducible factor 1 alpha (HIF-1α) and MYC proteins. Certain bacteria produce short-chain fatty acids (SCFAs), which activate CD8+ cells and genes involved in antigen processing and presentation, while other mechanisms support pro-tumor activities. The use of immune checkpoint inhibitors (ICIs) in selected CRC patients has shown promise, and the combination of these with drugs that inhibit aerobic glycolysis is currently being intensively researched to enhance the efficacy of immunotherapy.

National Trends in the Incidence of Sporadic Malignant Colorectal Polyps in Young Patients (20-49 Years): An 18-Year SEER Database Analysis

Background and Objectives: Conflicting guidelines exist for initiating average-risk colorectal cancer screening at the age of 45 years. The United States Preventive Services Task Force (USPSTF) changed its guidelines in 2021 to recommend initiating screening at 45 years due to an increasing incidence of young-onset colorectal cancer. However, the American College of Physicians (ACP) recently recommended not screening average-risk individuals between 45 and 49 years old. We aim to study the national trends in the incidence of sporadic malignant polyps (SMP) in patients from 20 to 49 years old. Materials and Methods: We analyzed the Surveillance, Epidemiology, and End Results database (2000-2017) on patients aged 20-49 years who underwent diagnostic colonoscopy with at least a single malignant sporadic colorectal polyp. Results: Of the 10,742 patients diagnosed with SMP, 42.9% were female. The mean age of incidence was 43.07 years (42.91-43.23, 95% CI). Approximately 50% of malignant polyps were diagnosed between 45 and 49 years of age, followed by 25-30% between 40 and 45. There was an upward trend in malignant polyps, with a decreased incidence of malignant villous adenomas and a rise in malignant adenomas and tubulovillous adenomas. Conclusions: Our findings suggest that almost half of the SMPs under 50 years occurred in individuals under age 45, younger than the current screening threshold recommended by the ACP. There has been an upward trend in malignant polyps in the last two decades. This reflects changes in tumor biology, and necessitates further research and support in the USPSTF guidelines to start screening at the age of 45 years.

How to Navigate the Treatment Spectrum from Multimodality Therapy to Observation Alone for ductal carcinoma in situ

DCIS detection has increased dramatically since the introduction of screening mammography. Current guidance concordant care recommends surgical intervention for all patients with DCIS, followed by radiation and/or endocrine therapy for some. Adjuvant therapies after surgical excision have reduced recurrence rates but not breast cancer mortality. Given the lack of evidence of current treatment regimens and the morbidity associated with these treatments, there is concern that DCIS is over-treated. Active surveillance may be a favorable alternative for selected patients and is currently being investigated through four international clinical trials.

Molecular basis of RNA-binding and autoregulation by the cancer-associated splicing factor RBM39

Pharmacologic depletion of RNA-binding motif 39 (RBM39) using aryl sulfonamides represents a promising anti-cancer therapy but requires high levels of the adaptor protein DCAF15. Consequently, novel approaches to deplete RBM39 in an DCAF15-independent manner are required. Here, we uncover that RBM39 autoregulates via the inclusion of a poison exon into its own pre-mRNA and identify the cis-acting elements that govern this regulation. We also determine the NMR solution structures of RBM39's tandem RNA recognition motifs (RRM1 and RRM2) bound to their respective RNA targets, revealing how RRM1 recognises RNA stem loops whereas RRM2 binds specifically to single-stranded N(G/U)NUUUG. Our results support a model where RRM2 selects the 3'-splice site of a poison exon and the RRM3 and RS domain stabilise the U2 snRNP at the branchpoint. Our work provides molecular insights into RBM39-dependent 3'-splice site selection and constitutes a solid basis to design alternative anti-cancer therapies.

Endoscopic Submucosal Dissection, Endoscopic Mucosal Resection, and Transanal Minimally Invasive Surgery for the Management of Rectal and Anorectal Lesions: A Narrative Review

Endoscopic submucosal dissection (ESD), endoscopic mucosal resection (EMR), and transanal minimally invasive surgery (TAMIS) are modern techniques that now play a crucial role in the treatment of colorectal lesions. ESD is a minimally invasive endoscopic procedure that allows for the resection of lesions of any size in a single piece, with clear advantages regarding oncological outcomes and recurrences. However, it is a complex technique, requiring high endoscopic skills, expertise, and specialized training, with higher rates of adverse events expected compared with EMR. EMR is another endoscopic technique used to remove superficial gastrointestinal tumors, particularly those that are limited to the mucosal layer. It is a faster and more accessible procedure, with fewer adverse events, although it only allows for an en-bloc resection of lesions measuring 15-20 mm. TAMIS is a minimally invasive surgical technique used to remove rectal tumors, involving the insertion of a single-port device through the anus, allowing for a better visualization and removal of the tumor with minimal disruption. This article reviews the current applications and evidence regarding these techniques, in search for the most adequate treatment for the removal of lesions in the rectum and anorectal junction, as these locations possess distinct characteristics that demand a more specific approach.

The Expression Pattern of Bcl-2 and Bax in the Tumor and Stromal Cells in Colorectal Carcinoma

Background and objectives: The epithelial and stromal tissues both play a role in the progression of colorectal cancer (CRC). The aim of this study was to assess the expression of anti-apoptotic Bcl-2 and pro-apoptotic Bax in the epithelium as well as the lamina propria of normal colonic controls, low-grade tumor samples and high-grade tumor samples. Materials and Methods: A total of 60 samples consisting of both normal colonic and carcinoma samples was collected from the Department of Pathology, Cytology and Forensic Medicine, University Hospital Center, Split from January 2020 to December 2021. The expression of Bcl-2 and Bax markers was semi-quantitatively and quantitatively evaluated by recording immunofluorescence stain intensity and by counting stained cells in the lamina propria and epithelium. Analysis of positive cells was performed using the Mann-Whitney test. Results: In all samples, Bcl-2 was significantly more expressed in the lamina propria when compared with the epithelium. Bax was significantly more expressed in the epithelium of normal and low-grade cancer samples when compared with their respective laminae propriae. The percentage of Bcl-2-positive cells in lamina propria is about two times lower in high-grade CRC and about three times lower in low-grade CRC in comparison with healthy controls. Contrary to this, the percentage of Bax-positive cells was greater in the epithelium of low-grade CRC in comparison with healthy control and high-grade CRC. Conclusions: Our study provides a new insight into Bcl-2 and Bax expression pattern in CRC. Evaluation of Bcl-2 expression in the lamina propria and Bax expression in the epithelium could provide important information for colorectal cancer prognosis as well as potential treatment strategies.

Network Pharmacology and Molecular Docking on the Molecular Mechanism of Jiawei-Huang Lian-Gan Jiang Decoction in the Treatment of Colorectal Adenomas

Purpose

Jiawei-Huang Lian-Gan Jiang decoction (JWHLGJD) was developed to treat and prevent the patients with colorectal adenomas (CRA) in China. This study is aimed to discover JWHLGJD's active compounds and demonstrate mechanisms of JWHLGJD against CRA through network pharmacology and molecular docking techniques.

Methods

All the components of JWHLGJD were retrieved from the pharmacology database of Traditional Chinese Medicine Systems Pharmacology (TCMSP). The GeneCards database, the Online Mendelian Inheritance in Man database (OMIM), the DrugBank database, and PharmGKB were used to obtain the genes matching the targets. Cytoscape created the compound-target network. The network of target protein-protein interactions (PPI) was constructed using the STRING database. Gene Ontology (GO) functional and the Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathways involved in the targets were analyzed by using the DAVID database. Cytoscape created the component-target-pathway (C-T-P) network. AutoDock Vina software was used to verify the molecular docking of JWHLGJD components and key targets. Core genes linked with survival and tumor microenvironment were analyzed through the Kaplan–Meier plotter and TIMER 2.0 databases, respectively.

Results

Compound-target network mainly contained 38 compounds and 130 targets of the JWHLGJD associated with CRA. TP53, MAPK1, JUN, HSP90AA1, and AKT1 were identified as core targets by the PPI network. KEGG pathway shows that the pathways in cancer, lipids, and atherosclerosis, PI3K-Akt signaling pathway and MAPK signaling pathway, are the most relevant pathways to CRA. The C-T-P network suggests that the active component in JWHLGJD is capable of regulating target genes of these related pathways. The results of molecular docking showed that berberine and stigmasterol were the top two compounds of JWHLGJD, which had high affinity with TP53 and MAPK1, respectively. And, MAPK1 exerted a more significant effect on the prognosis of adenocarcinoma, for it was highly associated with various immune cells.

Conclusion

Findings in this study provided light on JWHLGJD's active components, prospective targets, and molecular mechanism. It also gave a potential way to uncovering the scientific underpinning and therapeutic mechanism of traditional Chinese medicine (TCM) formulas.

Discovery of Long Non-Coding RNA MALAT1 Amplification in Precancerous Colorectal Lesions

A colorectal adenoma, an aberrantly growing tissue, arises from the intestinal epithelium and is considered as precursor of colorectal cancer (CRC). In this study, we investigated structural and numerical chromosomal aberrations in adenomas, hypothesizing that chromosomal instability (CIN) occurs early in adenomas. We applied array comparative genomic hybridization (aCGH) to fresh frozen colorectal adenomas and their adjacent mucosa from 16 patients who underwent colonoscopy examination. In our study, histologically similar colorectal adenomas showed wide variability in chromosomal instability. Based on the obtained results, we further stratified patients into four distinct groups. The first group showed the gain of MALAT1 and TALAM1, long non-coding RNAs (lncRNAs). The second group involved patients with numerous microdeletions. The third group consisted of patients with a disrupted karyotype. The fourth group of patients did not show any CIN in adenomas. Overall, we identified frequent losses in genes, such as TSC2, COL1A1, NOTCH1, MIR4673, and GNAS, and gene gain containing MALAT1 and TALAM1. Since long non-coding RNA MALAT1 is associated with cancer cell metastasis and migration, its gene amplification represents an important event for adenoma development.

Genetic Study of Chemokine Ligand 1 in Colorectal Carcinoma using Quantitative Real-Time PCR

Background: Carcinoma of colon is one of the prevalence carcinoma in the world and it is the most important cause of death in Western countries. The disease process is multifactorial; with etiology include inflammatory conditions of the digestive tract, environmental liableness and genetic factors. Chemokine Ligand1 was share in several mechanisms such as inflammatory process, chemo attraction, and others. Objective: The current study was conducted to analyze gene expression level of chemokine ligand 1 in colonic carcinoma and to deliberate the participant of it as genetic factors in its evolving and prognosis. Material and method: Chemokine Ligand1 gene expression level was evaluated in formalin-fixed, paraffin embedded tissue blocks that is retrospectively collected from 40 patients (8 women and 32 men) with carcinoma, and 40 patients of normal colonic tissues as control specimen by using Real-Time PCR. Results: The expression of Chemokine ligand 1 gene were established as 12.4112 folds in carcinoma specimen in relation to control tissue (1.3492).  Chemokine ligand 1 genes were found to be over-expressed in advanced stage tumors and elderly patients. Conclusions: Chemokine ligand1 can be considered as a recent biomarker and the possibility to use it as therapeutic target in the treatment of colonic carcinoma.

Accounting for Preinvasive Conditions in Analysis of Invasive Cancer Risk: Application to Breast Cancer

BACKGROUND

Preinvasive cancer conditions are often actively treated to minimize progression to life-threatening invasive cancers, but this creates challenges for analysis of invasive cancer risk. Conventional methods of treating preinvasive conditions as censoring events or targeting at the composite outcome could both lead to bias.

METHODS

We propose two solutions: one that provides exact estimates of risk based on distributional assumptions about progression, and one that provides risk bounds corresponding to extreme cases of no or complete progression. We compare these approaches through simulations and an analysis of the Sister Study data in the context of ductal carcinoma in situ (DCIS) and invasive breast cancer.

RESULTS

Simulations suggested important biases with conventional approaches, whereas the proposed estimate is consistent when progression parameters are correctly specified, and the risk bounds are robust in all scenarios. With Sister Study, the estimated lifetime risks for invasive breast cancer are 0.220 and 0.269 with DCIS censored or combined. Without detailed progression information, a sensitivity analysis suggested lifetime risk falls between the bounds of 0.214 and 0.269 across assumptions of 10%-95% of DCIS patients progressing to invasive cancer in an average of 1-10 years.

CONCLUSIONS

When estimating invasive cancer risk while preinvasive conditions are actively treated, it is important to consider the implied assumptions and potential biases of conventional approaches. Although still not perfect, we proposed two practical solutions that provide improved understanding of the underlying mechanism of invasive cancer.

Transcriptomic and Proteomic Study on the High-Fat Diet Combined With AOM/DSS-Induced Adenomatous Polyps in Mice

Objective

To screen and identify molecular targets and bacteria genus leading to adenomatous polyps in mouse induced by high-fat diet (HFD) +AOM/DSS using omics technology.

Methods

The molecular targets of colorectal adenoma disease were obtained from the GeneCards and OMIM database. The SPF C57BL mice were randomly divided into blank (Control) and AOM/DSS+HFD colorectal adenoma model (ADH) groups. The ADH model group was intraperitoneally injected with AOM reagent. Then, mice were given with 2.5% DSS (in free drinking water) and high-fat diet to establish the mouse model. During this period, the changes of physical signs of mice in each group were observed. After the end of modeling, HE staining was used to evaluate the histopathological change of mice. The differentially expressed genes and proteins in the Control group and ADH group were detected by RNA-seq transcriptome sequencing and Tandem Mass Tags (TMT) quantitative proteomics. The histological results were analyzed by intersection with the intestinal adenoma molecular targets obtained from the database. Moreover, the changes of intestinal flora in the two groups were examined. The correlation between targets and differential bacteria was analyzed and verified by Parallel Reaction Monitoring (PRM) to comprehensively evaluate the mouse model of adenomatous polyp induced by AOM/DSS+HFD.

Results

The general condition and histopathological results of mice confirmed that the ADH mouse model was successfully established and tubular adenoma was formed. A total of 604 genes and 42 proteins related to intestinal adenoma were obtained by histological analysis and database intersection analysis. The intestinal microflora of ADH mice was different from that of normal mice, and the constituents and abundance of intestinal flora were similar to those of human intestinal adenoma. GATA4 and LHPP were selected as potential pathological markers of the model mice by correlation analysis of targets and intestinal flora. The results of PRM verification were highly consistent with the results of RNA-Seq transcriptome sequencing and TMT analysis.

Conclusion

The pathological results, molecular pathological markers and the changes of intestinal flora suggest that the mouse ADH model is ideal for studying the transformation of inflammatory cancer. The ADH model will be helpful for understanding the occurrence and development of human colorectal cancer at the transcriptomic and proteomic level.

Screening of radiotracer for diagnosis of colorectal cancer liver metastasis based on MACC1-SPON2

Background

Metastasis-associated in colon cancer 1 (MACC1) and Spondin2 (SPON2) are newly discovered oncogenes, but little is known about their role in colorectal cancer(CRC) liver metastases. PET has become an important molecular imaging technology due to its high sensitivity and quantifiability. In particular, its targeted, specific molecular probes can detect biological behaviors. This study was designed to evaluate the different biological properties of ¹⁸F-FDG, ¹⁸F-FLT, and ¹⁸F-FMISO PET. The value of the CRC liver metastasis model explores the correlation and potential mechanisms of three tracers uptakes with tumor-related biological characteristics.

Methods

Human CRC cell lines(LoVo and HCT8), were cultured for in vitro radionuclide uptake experiments to compare the molecular imaging features of colorectal cancer cells with different metastatic potentials. Two kinds of cells were injected into the spleen of nude mice to establish a liver metastasis model. After the tumor formation, three kinds of tracer PET images were performed to evaluate the characteristics of live PET imaging of high and low liver metastasis colorectal cancer models. The expression levels of MACC1 and SPON2 in tissues were detected by immunohistochemistry and Western blot. Correlation between tracer uptake and expression of MACC1 and SPON2 in liver metastases was assessed by linear regression analysis.

Results

The uptake rate of in vitro three tracers uptake experiments was LoVo > HCT8. Micro-PET scan showed no significant difference between the ¹⁸F-FDG SUV values of the two cells (P > 0.05); there was significant difference between the ¹⁸F-FLT and ¹⁸F-FMISO SUV values (P < 0.05). All in vivo FLT and FMISO SUV values were significantly higher in LoVo tumors than in HCT8 tumors. The results of Western blot and immunohistochemistry showed that the expression levels of MACC1 and SPON2 in LoVo liver metastasis were higher than those in HCT8 (P < 0.05). The ¹⁸F-FLT SUVmax ratio was significantly correlated with the expression of MACC1 and SPON2 in hepatic metastases (r = 0.737, P = 0.0026; r = 0.842, P = 0.0002). The ¹⁸F-FMISO SUVmax ratio was only significantly correlated with the expression of MACC1 in hepatic metastasis (r = 0.770, P = 0.0013).

Conclusions

Early screening with ¹⁸F-FLT and ¹⁸F-FMISO tracers has important clinical value for the efficient diagnosis and treatment of colorectal cancer liver metastases.

Metabolic Reprogramming of Colorectal Cancer Cells and the Microenvironment: Implication for Therapy

Colorectal carcinoma (CRC) is one of the most frequently diagnosed carcinomas and one of the leading causes of cancer-related death worldwide. Metabolic reprogramming, a hallmark of cancer, is closely related to the initiation and progression of carcinomas, including CRC. Accumulating evidence shows that activation of oncogenic pathways and loss of tumor suppressor genes regulate the metabolic reprogramming that is mainly involved in glycolysis, glutaminolysis, one-carbon metabolism and lipid metabolism. The abnormal metabolic program provides tumor cells with abundant energy, nutrients and redox requirements to support their malignant growth and metastasis, which is accompanied by impaired metabolic flexibility in the tumor microenvironment (TME) and dysbiosis of the gut microbiota. The metabolic crosstalk between the tumor cells, the components of the TME and the intestinal microbiota further facilitates CRC cell proliferation, invasion and metastasis and leads to therapy resistance. Hence, to target the dysregulated tumor metabolism, the TME and the gut microbiota, novel preventive and therapeutic applications are required. In this review, the dysregulation of metabolic programs, molecular pathways, the TME and the intestinal microbiota in CRC is addressed. Possible therapeutic strategies, including metabolic inhibition and immune therapy in CRC, as well as modulation of the aberrant intestinal microbiota, are discussed.

Identification and Validation of New Cancer Stem Cell-Related Genes and Their Regulatory microRNAs in Colorectal Cancerogenesis

Significant progress has been made in the last decade in our understanding of the pathogenetic mechanisms of colorectal cancer (CRC). Cancer stem cells (CSC) have gained much attention and are now believed to play a crucial role in the pathogenesis of various cancers, including CRC. In the current study, we validated gene expression of four genes related to CSC, L1TD1, SLITRK6, ST6GALNAC1 and TCEA3, identified in a previous bioinformatics analysis. Using bioinformatics, potential miRNA-target gene correlations were prioritized. In total, 70 formalin-fixed paraffin-embedded biopsy samples from 47 patients with adenoma, adenoma with early carcinoma and CRC without and with lymph node metastases were included. The expression of selected genes and microRNAs (miRNAs) was evaluated using quantitative PCR. Differential expression of all investigated genes and four of six prioritized miRNAs (hsa-miR-199a-3p, hsa-miR-335-5p, hsa-miR-425-5p, hsa-miR-1225-3p, hsa-miR-1233-3p and hsa-miR-1303) was found in at least one group of CRC cancerogenesis. L1TD1, SLITRK6, miR-1233-3p and miR-1225-3p were correlated to the level of malignancy. A negative correlation between miR-199a-3p and its predicted target SLITRK6 was observed, showing potential for further experimental validation in CRC. Our results provide further evidence that CSC-related genes and their regulatory miRNAs are involved in CRC development and progression and suggest that some them, particularly miR-199a-3p and its SLITRK6 target gene, are promising for further validation in CRC.

Identification of key candidate genes and pathways associated with colorectal aberrant crypt foci-to-adenoma-to-carcinoma progression

AIM

The present study aimed to detect key candidate genes and pathways involved in colorectal aberrant crypt foci-to-adenoma-to-carcinoma progression.

BACKGROUND

Although colorectal cancer (CRC) is the third most common type of cancer, the involved signaling pathways and driver-genes remain largely unclear. CRC begins with the malignant transformation of precancerous lesions including aberrant crypt foci (ACF) and benign adenomatous polyp or adenoma.

METHODS

A list of formerly reported ACF, adenoma, and CRC-associated proteins was obtained from GeneCards, and then the data in online David Bioinformatics Resources was analyzed. The protein-protein interactions were surveyed utilizing String database and Cytoscape software. After hubs and bottlenecks were recognized, the key genes and pathways were identified through different bioinformatics analysis.

RESULTS

The most important pathways associated with colorectal aberrant crypt foci-to-adenoma progression were attributed to "pathways in cancer" and "chemokine signaling pathway" and those in adenoma-to-carcinoma progression were related to "pathways in cancer," "chemokine signaling pathway," and "Ras signaling pathway." The genes participating in these pathways are key ones. Furthermore, PRKACB, CUL2, and GSK3B were significant as the seed in the clusters related to adenoma and GNB1, RALBP1, ROCK1, and IKBKG in the clusters related to cancer.

CONCLUSION

The key candidate genes and pathways in progress CRC formed precursor lesions were identified by integrated bioinformatics analysis. The results could lead to a better understanding of the cause and underlying molecular events as well as detection of therapeutic targets for CRC.

Screening for Colorectal Cancer

Colorectal cancer screening is essential to detect and remove premalignant lesions to prevent the development of colorectal cancer. Multiple screening modalities are available, including colonoscopy and stool-based testing. Colonoscopy remains the gold standard for detection and removal of premalignant colorectal lesions. Screening guidelines by the American Cancer Society now recommend initiating screening for all average-risk adults at 45 years old. Family history of colorectal cancer, other cancers, and advanced colon polyps are strong risk factors that must be considered in order to implement earlier testing. Epidemiologic studies continue to show disparities in colorectal cancer incidence and mortality and wide variability in screening rates.

Metabolomic Markers of Colorectal Tumor With Different Clinicopathological Features

Background: Colorectal cancer (CRC) is the result of complex interactions between the tumor's molecular profile and metabolites produced by its microenvironment. Despite recent studies identifying CRC molecular subtypes, a metabolite classification system is still lacking. We aimed to explore the distinct phenotypes and subtypes of CRC at the metabolite level.

Methods: We conducted an untargeted metabolomics analysis of 51 paired tumor tissues and adjacent mucosa using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry. Multivariate analysis including principal component analysis, orthogonal partial least squares discriminant analysis and heat maps, univariate analysis, and pathway analysis were used to identify potential metabolite phenotypes of CRC. Unsupervised consensus clustering was used to identify robust metabolite subtypes, and evaluated their clinical relevance.

Results: A total of 173 metabolites (including nucleotides, carbohydrates, free fatty acids, and choline) were identified between CRC tumor tissue and adjacent mucosa. We found that lipid metabolism was closely related to the occurrence and progression of CRC. In particular, CRC tissues could be divided into three subtypes, and statistically significant correlations between different subtypes and clinical prognosis were observed.

Conclusions: CRC tumor tissue exhibits distinct metabolite phenotypes. Metabolite differences between subtypes may provide a basis and direction for further clinical individualized treatment planning.

Silencing or inhibition of H3K79 methyltransferase DOT1L induces cell cycle arrest by epigenetically modulating c-Myc expression in colorectal cancer

BACKGROUND

Epigenetic regulations play pivotal roles in tumorigenesis and cancer development. Disruptor of telomeric silencing-1-like (DOT1L), also known as KMT4, is the only identified histone methyltransferase that catalyzes the mono-, di-, and tri-methylation of lysine 79 histone 3 (H3K79). However, little is known about the effect of H3K79 methylation on the modulation of colorectal cancer (CRC) development.

METHODS

DOT1L expression profiles in different subgroups of CRC tissues and its clinical significances were analyzed from some online datasheets. DOT1L in CRC cell lines was silenced by either lentivirus-mediated knockdown or inhibited by its specific inhibitor, EPZ004777. Then cell proliferation was detected by MTT assay, BrdU assay, and soft agar assay; cell cycle was detected by cytometry; and tumorigenicity was detected by using nude mice xenograft models. Clinical co-expression was analyzed between DOT1L and c-Myc. Chromatin immunoprecipitation (ChIP) assay was used to determine whether the translation of c-Myc was epigenetically regulated by H3K79me2 induced by DOT1L. c-Myc overexpression was used to rescue the cell cycle arrest and tumor growth induced by DOT1L silencing or inhibition in CRC.

RESULTS

We found that DOT1L was highly expressed in colorectal cancer and was negatively related to the prognosis of patients with CRC. Silencing or inhibition of DOT1L blocked cell proliferation, BrdU incorporation, self-renewal capability in vitro, and tumorigenicity in vivo. Besides, inhibition or silencing of DOT1L also induced cell cycle arrest at S phase, as well as decreased the expression of CDK2 and Cyclin A2. Furthermore, in the clinical databases of CRC, we found that the expression of DOT1L was positively correlated with that of c-Myc, a major regulator in the upstream of cell cycle-related factors. Besides, c-Myc expression was downregulated after DOT1L knockdown and c-Myc restoration rescued decrease of cell proliferation, BrdU corporation, self-renewal capability, cell cycle progression in vitro and tumorigenicity in vivo induced by DOT1L silencing. Then we found that H3K79 methylation was decreased after DOT1L knockdown. ChIP assay showed that H3K79me2 was enriched on the - 682~+ 284 region of c-Myc promoter, and the enrichment was decreased after DOT1L inhibition.

CONCLUSIONS

Our results show that DOT1L epigenetically promotes the transcription of c-Myc via H3K79me2. DOT1L silencing or inhibition induces cell cycle arrest at S phase. DOT1L is a potential marker for colorectal cancer and EPZ004777 may be a potential drug for the treatment of colorectal cancer.

Molecular characterization of colorectal adenomas reveals POFUT1 as a candidate driver of tumor progression

Removal of colorectal adenomas is an effective strategy to reduce colorectal cancer (CRC) mortality rates. However, as only a minority of adenomas progress to cancer, such strategies may lead to overtreatment. The present study aimed to characterize adenomas by in‐depth molecular profiling, to obtain insights into altered biology associated with the colorectal adenoma‐to‐carcinoma progression. We obtained low‐coverage whole genome sequencing, RNA sequencing and tandem mass spectrometry data for 30 CRCs, 30 adenomas and 18 normal adjacent colon samples. These data were used for DNA copy number aberrations profiling, differential expression, gene set enrichment and gene‐dosage effect analysis. Protein expression was independently validated by immunohistochemistry on tissue microarrays and in patient‐derived colorectal adenoma organoids. Stroma percentage was determined by digital image analysis of tissue sections. Twenty‐four out of 30 adenomas could be unambiguously classified as high risk (n = 9) or low risk (n = 15) of progressing to cancer, based on DNA copy number profiles. Biological processes more prevalent in high‐risk than low‐risk adenomas were related to proliferation, tumor microenvironment and Notch, Wnt, PI3K/AKT/mTOR and Hedgehog signaling, while metabolic processes and protein secretion were enriched in low‐risk adenomas. DNA copy number driven gene‐dosage effect in high‐risk adenomas and cancers was observed for POFUT1, RPRD1B and EIF6. Increased POFUT1 expression in high‐risk adenomas was validated in tissue samples and organoids. High POFUT1 expression was also associated with Notch signaling enrichment and with decreased goblet cells differentiation. In‐depth molecular characterization of colorectal adenomas revealed POFUT1 and Notch signaling as potential drivers of tumor progression.

What's new?

Removal of colorectal adenomas is an effective strategy to reduce colorectal cancer (CRC) mortality rates. However, as only a minority of adenomas progress to cancer, such strategies may lead to overtreatment. While high‐risk adenomas, defined by specific DNA copy number aberrations, have an increased risk of progression, the mechanisms underlying colorectal adenoma‐to‐carcinoma progression remain unclear. This molecular characterization of colorectal adenomas, CRCs, and normal adjacent colon samples demonstrates that biological processes inherent to CRC are already more active in high‐risk adenomas compared to low‐risk adenomas. Moreover, the findings highlight POFUT1 and Notch signaling as potential drivers of colorectal tumor development.

Adenoma Detection before and after the age of 50: a retrospective analysis of Lebanese outpatients

Background and aim

Colorectal cancer (CRC) has an increased impact on the Lebanese population’s morbidity and mortality. This study evaluated the situation of adenoma detection in an outpatient clinic in Lebanon.

Patients and methods

918 patients underwent colonoscopy over a period of 24 months by a qualified physician. Biopsy results were divided into normal versus abnormal colonic tissue, which was further subdivided into number of polyps and cancer.

Results

Out of 918 individuals included, 82 cases of Crohn’s colitis (8.93%) and 22 cases of ulcerative colitis (2.39%) were identified. A total of 42 cases of CRC (4.58%) and 188 cases of adenomatous polyps (20.48%) were identified. The data show that age >50 years and male gender significantly correlate with increased incidence of precancerous and cancerous polyps. Further exploring the results by age groups and gender, detection of adenomatous polyps in women aged 40–49 (8.33%) was significantly different from their female counterparts aged ≥50 years old (25.26%) (p<0.01). However, no statistical difference between detection of adenomas was found between men aged 40–49 (33.33%) and their male counterparts aged ≥50 years old (37.5%) (p=0.6).

Conclusion

Within the limitations of this study, the incidence of CRC and adenomatous polyps falls in the high range compared with international studies. Furthermore, symptomatic male patients aged 40–49 appear to exhibit detection rates of adenomas similar to their counterparts aged ≥50 years old. Subjects younger than 50 years underwent diagnostic rather than screening colonoscopy, which introduces some selection bias. Nevertheless, these findings can serve as a basis for further studies.

Metabolomic alterations and chromosomal instability status in gastric cancer

AIM

To explore the correlation of metabolomics profiles of gastric cancer (GC) with its chromosomal instability (CIN) status.

METHODS

Nineteen GC patients were classified as CIN and non-CIN type by The Cancer Genome Atlas Research Group system, based on 409 oncogenes and tumor suppressor genes sequenced. The aqueous metabolites of the GC tumor and its surrounding adjacent healthy tissues were identified through liquid chromatography-mass spectrometry. Groups were compared by defining variable importance in projection score of > 1.2, a fold change value or its reciprocal of > 1.2, and a P value of < 0.05 as a significant difference.

RESULTS

In total, twelve men and seven women were enrolled, with a median age of 66 years (range, 47-87 years). The numbers of gene alterations in the CIN GC group were significantly higher than those in the non-CIN GC (32-218 vs 2-17; P < 0.0005). Compared with the adjacent healthy tissues, GC tumors demonstrated significantly higher aspartic acid, citicoline, glutamic acid, oxidized glutathione, succinyladenosine, and uridine diphosphate-N-acetylglucosamine levels, but significantly lower butyrylcarnitine, glutathione hydroxyhexanoycarnitine, inosinic acid, isovalerylcarnitine, and threonine levels (all P < 0.05). CIN tumors contained significantly higher phosphocholine and uridine 5'-monophosphate levels but significantly lower beta-citryl-L-glutamic acid levels than did non-CIN tumors (all P < 0.05). CIN GC tumors demonstrated additional altered pathways involving alanine, aspartate, and glutamate metabolism, glyoxylate and dicarboxylate metabolism, histidine metabolism, and phenylalanine, tyrosine, and tryptophan biosynthesis.

CONCLUSION

Metabolomic profiles of GC tumors and the adjacent healthy tissue are distinct, and the CIN status is associated with downstream metabolic alterations in GC.

Consensus molecular subtype classification of colorectal adenomas

Consensus molecular subtyping is an RNA expression‐based classification system for colorectal cancer (CRC). Genomic alterations accumulate during CRC pathogenesis, including the premalignant adenoma stage, leading to changes in RNA expression. Only a minority of adenomas progress to malignancies, a transition that is associated with specific DNA copy number aberrations or microsatellite instability (MSI). We aimed to investigate whether colorectal adenomas can already be stratified into consensus molecular subtype (CMS) classes, and whether specific CMS classes are related to the presence of specific DNA copy number aberrations associated with progression to malignancy. RNA sequencing was performed on 62 adenomas and 59 CRCs. MSI status was determined with polymerase chain reaction‐based methodology. DNA copy number was assessed by low‐coverage DNA sequencing (n = 30) or array‐comparative genomic hybridisation (n = 32). Adenomas were classified into CMS classes together with CRCs from the study cohort and from The Cancer Genome Atlas (n = 556), by use of the established CMS classifier. As a result, 54 of 62 (87%) adenomas were classified according to the CMS. The CMS3 ‘metabolic subtype’, which was least common among CRCs, was most prevalent among adenomas (n = 45; 73%). One of the two adenomas showing MSI was classified as CMS1 (2%), the ‘MSI immune’ subtype. Eight adenomas (13%) were classified as the ‘canonical’ CMS2. No adenomas were classified as the ‘mesenchymal’ CMS4, consistent with the fact that adenomas lack invasion‐associated stroma. The distribution of the CMS classes among adenomas was confirmed in an independent series. CMS3 was enriched with adenomas at low risk of progressing to CRC, whereas relatively more high‐risk adenomas were observed in CMS2. We conclude that adenomas can be stratified into the CMS classes. Considering that CMS1 and CMS2 expression signatures may mark adenomas at increased risk of progression, the distribution of the CMS classes among adenomas is consistent with the proportion of adenomas expected to progress to CRC. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Clinically Relevant Anti-Inflammatory Agents for Chemoprevention of Colorectal Cancer: New Perspectives

Substantial efforts are underway for prevention of early stages or recurrence of colorectal cancers (CRC) or new polyp formation by chemoprevention strategies. Several epidemiological, clinical and preclinical studies to date have supported the chemopreventive potentials of several targeted drug classes including non-steroidal anti-inflammatory drugs (NSAIDs) (aspirin, naproxen, sulindac, celecoxib, and licofelone), statins and other natural agents—both individually, and in combinations. Most preclinical trials although were efficacious, only few agents entered clinical trials and have been proven to be potential chemopreventive agents for colon cancer. However, there are limitations for these agents that hinder their approval by the food and drug administration for chemoprevention use in high-risk individuals and in patients with early stages of CRC. In this review, we update the recent advancement in pre-clinical and clinical development of selected anti-inflammatory agents (aspirin, naproxen, sulindac, celecoxib, and licofelone) and their combinations for further development as novel colon cancer chemopreventive drugs. We provide further new perspectives from this old research, and insights into precision medicine strategies to overcome unwanted side-effects and overcoming strategies for colon cancer chemoprevention.

Bioinformatics Analysis Reveals Most Prominent Gene Candidates to Distinguish Colorectal Adenoma from Adenocarcinoma

Colorectal cancer (CRC) is one of the leading causes of death by cancer worldwide. Bowel cancer screening programs enable us to detect early lesions and improve the prognosis of patients with CRC. However, they also generate a significant number of problematic polyps, e.g., adenomas with epithelial misplacement (pseudoinvasion) which can mimic early adenocarcinoma. Therefore, biomarkers that would enable us to distinguish between adenoma with epithelial misplacement (pseudoinvasion) and adenoma with early adenocarcinomas (true invasion) are needed. We hypothesized that the former are genetically similar to adenoma and the latter to adenocarcinoma and we used bioinformatics approach to search for candidate genes that might be potentially used to distinguish between the two lesions. We used publicly available data from Gene Expression Omnibus database and we analyzed gene expression profiles of 252 samples of normal mucosa, colorectal adenoma, and carcinoma. In total, we analyzed 122 colorectal adenomas, 59 colorectal carcinomas, and 62 normal mucosa samples. We have identified 16 genes with differential expression in carcinoma compared to adenoma: COL12A1, COL1A2, COL3A1, DCN, PLAU, SPARC, SPON2, SPP1, SULF1, FADS1, G0S2, EPHA4, KIAA1324, L1TD1, PCKS1, and C11orf96. In conclusion, our in silico analysis revealed 16 candidate genes with different expression patterns in adenoma compared to carcinoma, which might be used to discriminate between these two lesions.

Aurora kinase A localises to mitochondria to control organelle dynamics and energy production

Many epithelial cancers show cell cycle dysfunction tightly correlated with the overexpression of the serine/threonine kinase Aurora A (AURKA). Its role in mitotic progression has been extensively characterised, and evidence for new AURKA functions emerges. Here, we reveal that AURKA is located and imported in mitochondria in several human cancer cell lines. Mitochondrial AURKA impacts on two organelle functions: mitochondrial dynamics and energy production. When AURKA is expressed at endogenous levels during interphase, it induces mitochondrial fragmentation independently from RALA. Conversely, AURKA enhances mitochondrial fusion and ATP production when it is over-expressed. We demonstrate that AURKA directly regulates mitochondrial functions and that AURKA over-expression promotes metabolic reprogramming by increasing mitochondrial interconnectivity. Our work paves the way to anti-cancer therapeutics based on the simultaneous targeting of mitochondrial functions and AURKA inhibition.

Structures called mitochondria power cells by turning oxygen and sugar into chemical energy. Each cell can have thousands of mitochondria, which work together to supply changing energy demands. They can fuse together or break apart, forming networks that change size and produce different amounts of energy. Getting the balance right is crucial; if energy levels are too low, the cell will not be able to grow and divide. If energy levels are too high, the cell can grow at a faster rate, which can contribute to the cell becoming cancerous.

Although we know that mitochondria provide energy, it is not clear how they communicate to fine-tune the supply. Some clues come from cancer cells that seem dependent on their mitochondria for survival. In these cells, levels of a protein called AURKA are higher than normal. AURKA helps cells to divide, and it interacts with many different proteins. This complexity makes it difficult to work out exactly what AURKA does, but it is possible that it plays a role in energy supply.

Bertolin et al. have now investigated whether mitochondria use AURKA to communicate inside human breast cancer cells. Tagging AURKA proteins with a fluorescent marker revealed that it accumulates inside mitochondria. Once it gets there, AURKA changes the shape of the mitochondria, which has dramatic effects on their capacity to produce energy. At normal levels, AURKA causes the mitochondria to fragment, breaking apart into smaller pieces. This maintains their energy output at a normal level. If AURKA levels are too high, the mitochondria fuse together and produce more energy. This means AURKA could help to fuel fast-growing cancer cells.

Current drugs that aim to treat cancer by blocking the activity of AURKA show poor results. This is partly due to the fact that the protein has so many different roles in the cell. Finding that AURKA affects mitochondria is the first step in understanding one of its unknown roles. It also suggests the possibility of developing new drugs to change how mitochondria make energy in cancer cells that contain high levels of AURKA.

Interaction between polymorphisms in aspirin metabolic pathways, regular aspirin use and colorectal cancer risk: A case-control study in unselected white European populations

Regular aspirin use is associated with reduced risk of colorectal cancer (CRC). Variation in aspirin's chemoprevention efficacy has been attributed to the presence of single nucleotide polymorphisms (SNPs). We conducted a meta-analysis using two large population-based case-control datasets, the UK-Leeds Colorectal Cancer Study Group and the NIH-Colon Cancer Family Registry, having a combined total of 3325 cases and 2262 controls. The aim was to assess 42 candidate SNPs in 15 genes whose association with colorectal cancer risk was putatively modified by aspirin use, in the literature. Log odds ratios (ORs) and standard errors were estimated for each dataset separately using logistic regression adjusting for age, sex and study site, and dataset-specific results were combined using random effects meta-analysis. Meta-analysis showed association between SNPs rs6983267, rs11694911 and rs2302615 with CRC risk reduction (All P<0.05). Association for SNP rs6983267 in the CCAT2 gene only was noteworthy after multiple test correction (P = 0.001). Site-specific analysis showed association between SNPs rs1799853 and rs2302615 with reduced colon cancer risk only (P = 0.01 and P = 0.004, respectively), however neither reached significance threshold following multiple test correction. Meta-analysis of SNPs rs2070959 and rs1105879 in UGT1A6 gene showed interaction between aspirin use and CRC risk (Pinteraction = 0.01 and 0.02, respectively); stratification by aspirin use showed an association for decreased CRC risk for aspirin users having a wild-type genotype (rs2070959 OR = 0.77, 95% CI = 0.68-0.86; rs1105879 OR = 0.77 95% CI = 0.69-0.86) compared to variant allele cariers. The direction of the interaction however is in contrast to that published in studies on colorectal adenomas. Both SNPs showed potential site-specific interaction with aspirin use and colon cancer risk only (Pinteraction = 0.006 and 0.008, respectively), with the direction of association similar to that observed for CRC. Additionally, they showed interaction between any non-steroidal anti-inflammatory drugs (including aspirin) use and CRC risk (Pinteraction = 0.01 for both). All gene x environment (GxE) interactions however were not significant after multiple test correction. Candidate gene investigation indicated no evidence of GxE interaction between genetic variants in genes involved in aspirin pathways, regular aspirin use and colorectal cancer risk.

Lumican and versican protein expression are associated with colorectal adenoma-to-carcinoma progression

Background

One prominent event associated with colorectal adenoma-to-carcinoma progression is genomic instability. Approximately 85% of colorectal cancer cases exhibit chromosomal instability characterized by accumulation of chromosome copy number aberrations (CNAs). Adenomas with gain of chromosome 8q, 13q, and/or 20q are at high risk of progression to cancer. Tumor progression is also associated with expansion of the extracellular matrix (ECM) and the activation of non-malignant cells within the tumor stroma. The glycoproteins versican and lumican are overexpressed at the mRNA level in colon carcinomas compared to adenomas, and are associated with the formation of tumor stroma.

Purpose

The aim of this study was to characterize versican and lumican protein expression in tumor progression and investigate their association with CNAs commonly associated with adenoma-to-carcinoma progression.

Methods

Tissue microarrays were constructed with colon adenomas and carcinomas that were characterized for MSI-status and DNA copy number gains of chromosomes 8q, 13q and 20q. Sections were immunohistochemically stained for lumican and versican. Protein expression levels were evaluated using digitized slides, and scores were finally dichotomized into a positive or negative score per sample.

Results

Lumican and versican expression were both observed in neoplastic cells and in the tumor stroma of colon adenomas and carcinomas. Lumican expression was more frequently present in epithelial cells of carcinomas than adenomas (49% versus 18%; P = 0.0001) and in high-risk adenomas and carcinomas combined compared to low-risk adenomas (43% versus 16%; P = 0.005). Versican staining in the tumor stroma was more often present in high-risk adenomas combined with carcinomas compared to low-risk adenomas (57% versus 36%; P = 0.03) and was associated with the presence of gain of 13q (71% versus 44%; P = 0.04).

Conclusion

Epithelial lumican and stromal versican protein expression are increased during colorectal adenoma-to-carcinoma progression.

Lifestyle and Sporadic Colorectal Cancer in India

BACKGROUND

The study evaluated the patient, lifestyle and tumor profile in patients undergoing upfront surgery for sporadic colorectal cancer (CRC) in Indian population.

MATERIALS AND METHODS

One hundred consecutive patients were included. Details related to their demographic profile, habits, signs and symptoms, tumor profile, further treatment and follow up were recorded.

RESULTS

The majority of the patients had colonic cancer (68%), advanced tumor stage 3 and 4 (46%), moderately differentiated tumors (70%) with absence of lymphatic invasion (60%) and metastasis (90%). Correlations between tumor location and abdominal pain (p-value 0.002), bleeding per rectum (p-value <0.001), difficulty in micturition (p-value 0.012) and constipation (p-value 0.007) were found to be statistically significant. Abdominal pain was more frequently reported in patients with metastasis (p-value 0.031). Loss of weight statistically correlated with absence of lymphatic invasion (p-value 0.047). Associations between tumor stage and alcohol intake (p-value 0.050) and non vegetarian diet (p-value 0.006); lymphatic invasion and intake of spicy food (p-value 0.040) and non vegetarian diet (p-value 0.001) and metastasis and alcohol intake (p-value 0.041) were also observed. Age and tumor grade were also correlated (p-value 0.020).

CONCLUSIONS

Minimizing the adverse lifestyle factors can help in reducing the overall incidence of CRC in the Indian population.

Expressions of TIMP-1, COX-2 and MMP-7 in Colon Polyp and Colon Cancer

Objective

We aimed to investigate the relationship of expression of matrix metalloproteinase-7 (MMP-7), tissue inhibitor of metalloproteinase-1 (TIMP-1) and cyclooxygenase-2 (COX-2) in colon cancer and its predecessor colon polyp.

Materials and methods

This study included 29 patients with colon polyp, 19 patients with colon cancer and 65 healthy control subjects. The expressions of MMP-7, TIMP-1 and COX-2 were investigated by real time-polymerase chain reaction (RT-PCR).

Results

The expressions of TIMP-1, COX-2 and MMP-7 levels were significantly higher in polyp tissue compared to normal tissue (p = 0.024, p < 0.001, p = 0.009, respectively). Expression of TIMP-1, COX-2 and MMP-7 in cancer tissues were higher than both normal tissue and polyp tissue (p = 0.009 and p = 0.001; p < 0.001 and p < 0.001; p = 0.029 and p = 0.008, respectively). In the cancer group, no significant relationship was detected between metastasis and MMP-7, TIMP-1 and COX-2 expressions (p > 0.05). In the polyp tissues, no significant relationship was detected between the histologic type and size of polyps and MMP-7, TIMP-1 and COX-2 levels (p > 0.05). The areas under the receiver operating characteristic (ROC) curve for the cancer group were 0.821 for TIMP-1, 0.888 for COX-2, and 0.880 for MMP-7 (p = 0 < 0.001).

Conclusion

A role and implication of expressions of MMP-7, COX-2 and TIMP-1 in colon cancer is predicted.

How to cite this article

Bengi G, Keles D, Topalak Ö, Yalçin M, Kiyak R, Oktay G. Expressions of TIMP-1, COX-2 and MMP-7 in Colon Polyp and Colon Cancer. Euroasian J Hepato-Gastroenterol 2015;5(2):74-79.

Dissecting characteristics and dynamics of differentially expressed proteins during multistage carcinogenesis of human colorectal cancer

AIM: To discover novel biomarkers for early diagnosis, prognosis or treatment of human colorectal cancer.

METHODS: iTRAQ 2D LC-MS/MS analysis was used to identify differentially expressed proteins (DEPs) in the human colonic epithelial carcinogenic process using laser capture microdissection-purified colonic epithelial cells from normal colon, adenoma, carcinoma in situ and invasive carcinoma tissues.

RESULTS: A total of 326 DEPs were identified, and four DEPs (DMBT1, S100A9, Galectin-10, and S100A8) with progressive alteration in the carcinogenic process were further validated by immunohistochemistry. The DEPs were involved in multiple biological processes including cell cycle, cell adhesion, translation, mRNA processing, and protein synthesis. Some of the DEPs involved in cellular process such as “translation” and “mRNA splicing” were progressively up-regulated, while some DEPs involved in other processes such as “metabolism” and “cell response to stress” was progressively down-regulated. Other proteins with up- or down-regulation at certain stages of carcinogenesis may play various roles at different stages of the colorectal carcinogenic process.

CONCLUSION: These findings give insights into our understanding of the mechanisms of colorectal carcinogenesis and provide clues for further investigation of carcinogenesis and identification of biomarkers.

Upregulation of spondin-2 predicts poor survival of colorectal carcinoma patients

Colorectal cancer (CRC) is the third and second most common cancer in males and females worldwide, respectively. Spondin-2 is a conserved secreted extracellular matrix protein and a candidate cancer biomarker. Here we found that Spondin-2 mRNA was upregulated in CRC tissues using quantitative RT-PCR and data-mining of public Oncomine microarray datasets. Spondin-2 protein was increased in CRC tissues, as revealed by immunohistochemistry analyses of two tissue microarrays containing 180 cases. Spondin-2 gene expression was significantly associated with CRC stage, T stage, M stage and Dukes stage, while its protein was associated with age and M stage. Kaplan-Meier analysis revealed that the upregulated Spondin-2 mRNA and protein predicted poor prognosis of CRC patients. Univariate and multivariate Cox regression analyses indicated that grade, recurrence, N stage and high Spondin-2 were independent predictors of overall survival of CRC patients. ELISA revealed that plasma Spondin-2 was upregulated in CRC and dropped after surgery. Receiver operating characteristic curve analysis demonstrated that plasma Spondin-2 has superior predictive performance for CRC with an area under the curve of 0.959 and the best sensitivity/specificity of 100%/90%. Furthermore, ectopic expression of Spondin-2 enhanced colon cancer cell proliferation. Spondin-2 could be an independent diagnostic and prognostic biomarker of colon cancer.

SPON2, a newly identified target gene of MACC1, drives colorectal cancer metastasis in mice and is prognostic for colorectal cancer patient survival

MACC1 (metastasis associated in colon cancer 1) is a prognostic biomarker for tumor progression, metastasis and survival of a variety of solid cancers including colorectal cancer (CRC). Here we aimed to identify the MACC1-induced transcriptome and key players mediating the MACC1-induced effects in CRC. We performed microarray analyses using CRC cells ectopically overexpressing MACC1. We identified more than 1300 genes at least twofold differentially expressed, including the gene SPON2 (Spondin 2) as 90-fold upregulated transcriptional target of MACC1. MACC1-dependent SPON2 expression regulation was validated on mRNA and protein levels in MACC1 high (endogenously or ectopically) and low (endogenously or by knockdown) expressing cells. Chromatin immunoprecipitation analysis demonstrated the binding of MACC1 to the gene promoter of SPON2. In cell culture, ectopic SPON2 overexpression induced cell viability, migration, invasion and colony formation in endogenously MACC1 and SPON2 low expressing cells, whereas SPON2 knockdown reduced proliferative, migratory and invasive abilities in CRC cells with high endogenous MACC1 and SPON2 expression. In intrasplenically transplanted NOD/SCID mice, metastasis induction was analyzed with control or SPON2-overexpressing CRC cells. Tumors with SPON2 overexpression induced liver metastasis (vs control animals without any metastases, P=0.0036). In CRC patients, SPON2 expression was determined in primary tumors (stages I-III), and survival time was analyzed by Kaplan-Meier method. CRC patients with high SPON2 expressing primary tumors demonstrated 8 months shorter metastasis-free survival (MFS) compared with patients with low SPON2 levels (P=0.053). Combining high levels of SPON2 and MACC1 improved the identification of high-risk patients with a 20-month shorter MFS vs patients with low biomarker expression. In summary, SPON2 is a transcriptional target of the metastasis gene MACC1. SPON2 induces cell motility in vitro and CRC metastasis in mice. In patients, SPON2 serves as prognostic indicator for CRC metastasis and survival, and might represent a promising target for therapeutic approaches.

Therapeutic potential of cyclooxygenase-3 inhibitors in the management of glioblastoma

In this study we investigated the expression of COX-1, COX-2 and COX-3 mRNA in C6 glioblastoma and normal brain tissues and the effects of acetaminophen, indomethacin or metamizole treatments on the development of C6 glioblastoma in relation with COX inhibition. Glioblastoma cells were inoculated intracerebrally into frontal lobe of adult male Wistar albino rats. 10 days after inoculation, rats were treated with 150 mg/kg acetaminophen, 10 mg/kg indomethacin or 150 mg/kg metamizole. The tumor size was measured histologically and total RNA was isolated from tumor or normal brain tissue and mRNA levels of COX isoforms were determined by qRT-PCR. Our results showed the presence of COX-1, COX-2 and COX-3 expressions in both C6 glioblastoma and normal brain tissues. In tumor tissues COX-3 expression was significantly higher than normal brain tissue (p < 0.05) while there was no significant difference in COX-1 and COX-2 expressions. Acetaminophen and indomethacin decreased the tumor size by 71 and 43 % by inhibiting COX-3 mRNA expression around 87 and 91 % respectively. For the first time our study proposes a possible relationship between COX-3 mRNA expression and C6 glioblastoma development. We also suggested that the inhibition of COX-3 enzyme may be responsible for decrease in tumor size in part, the mechanism by which acetaminophen and indomethacin decreased rat C6 glioblastoma growth. However, the molecular events responsible for COX-3 effects on tumor development are still unresolved as these drugs exert their anti-cancer effect via both COX-3 dependent and independent mechanisms.

Association of ITGA2 C807T polymorphism with risk of colorectal adenoma and colorectal cancer

AIM: To evaluate the impact of the ITGA2 C807T gene polymorphism on the risk of colorectal adenoma (CRA) and colorectal cancer (CRC) in a Chinese Han population.

METHODS: A hospital-based case-control study was conducted, including 95 healthy controls, 48 patients with CRA and 89 patients with CRC. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Association of the genotypes with the clinical and pathological features of CRC was evaluated.

RESULTS: The frequencies of the genotypes and alleles in CRC were significantly different from those of controls, but there were no significant differences between CRA and controls. Compared with individuals with the wild type genotype CC, subjects with the variant genotypes (CT + TT) had a significantly higher risk of CRA and CRC. In stratified analyses, the elevated CRC risk was especially evident in older individuals, females, smokers, drinkers, well-educated subjects, mental workers and urban subjects. However, no correlation was observed between CRA patients and controls in stratified analyses. When stratified by clinicopathological features such as lesion distribution, pathology subtype, tumor size, differentiation degree, depth of invasion, lymph node metastasis and Duke's stage in patients with CRC, no associations were observed in the polymorphism distributions.

CONCLUSION: The ITGA2 C807T polymorphism may be associated with an increased risk of CRA and CRC.

Molecular mechanism of anticancer effect of Sclerotium rolfsii lectin in HT29 cells involves differential expression of genes associated with multiple signaling pathways: A microarray analysis

Sclerotium rolfsii lectin (SRL) is a lectin isolated from fungus S. rolfsii and has high binding specificity toward the oncofetal Thomsen-Friedenreich carbohydrate antigen (Galβ1-3GalNAc-α-O-Ser/Thr, T or TF), which is expressed in more than 90% of human cancers. Our previous studies have shown that binding of SRL to human colon, breast and ovarian cancer cells induces cell apoptosis in vitro and suppresses tumor growth in vivo. This study investigated the SRL-mediated cell signaling in human colon cancer HT29 cells by mRNA and miRNA microarrays. It was found that SRL treatment results in altered expression of several hundred molecules including mitogen-activated protein kinase (MAPK) and c-JUN-associated, apoptosis-associated and cell cycle and DNA replication-associated signaling molecules. Pathway analysis using GeneSpring 12.6.1 revealed that SRL treatment induces changes of MAPK and c-JUN-associated signaling pathways as early as 2 h while changes of cell cycle, DNA replication and apoptosis pathways were significantly affected only after 24 h. A significant change of cell miRNA expression was also observed after 12 h treatment of the cells with SRL. These changes were further validated by quantitative real time polymerase chain reaction and immunoblotting. This study thus suggests that the presence of SRL affects multiple signaling pathways in cancer cells with early effects on cell proliferation pathways associated with MAPK and c-JUN, followed by miRNA-associated cell activity and apoptosis. This provides insight information into the molecular mechanism of the anticancer activity of this fungal lectin.

Absolute Proteome Analysis of Colorectal Mucosa, Adenoma, and Cancer Reveals Drastic Changes in Fatty Acid Metabolism and Plasma Membrane Transporters

Colorectal cancer is a leading cause of cancer-related death. It develops from normal enterocytes, through a benign adenoma stage, into the cancer and finally into the metastatic form. We previously compared the proteomes of normal colorectal enterocytes, cancer and nodal metastasis to a depth of 8100 proteins and found extensive quantitative remodeling between normal and cancer tissues but not cancer and metastasis (Wiśniewski et al. PMID 22968445). Here we utilize advances in the proteomic workflow to perform an in depth analysis of the normal tissue (N), the adenoma (A), and the cancer (C). Absolute proteomics of 10 000 proteins per patient from microdissected formalin-fixed and paraffin-embedded clinical material established a quantitative protein repository of the disease. Between N and A, 23% of all proteins changed significantly, 17.8% from A to C and 21.6% from N to C. Together with principal component analysis of the patient groups, this suggests that N, A, and C are equidistant but not on one developmental line. Our proteomics approach allowed us to assess changes in varied cell size, the composition of different subcellular components, and alterations in basic biological processes including the energy metabolism, plasma membrane transport, DNA replication, and transcription. This revealed several-fold higher concentrations of enzymes in fatty acid metabolism in C compared with N, and unexpectedly, the same held true of plasma membrane transporters.

EZH2 dependent H3K27me3 is involved in epigenetic silencing of ID4 in prostate cancer

Inhibitor of DNA binding/differentiation protein 4 (ID4) is dominant negative helix loop helix transcriptional regulator is epigenetically silenced due to promoter hyper-methylation in many cancers including prostate. However, the underlying mechanism involved in epigenetic silencing of ID4 is not known. Here, we demonstrate that ID4 promoter methylation is initiated by EZH2 dependent tri-methylation of histone 3 at lysine 27 (H3K27me3). ID4 expressing (LNCaP) and non-expressing (DU145 and C81) prostate cancer cell lines were used to investigate EZH2, H3K27me3 and DNMT1 enrichment on ID4 promoter by Chromatin immuno-precipitation (ChIP). Enrichment of EZH2, H3K27Me3 and DNMT1 in DU145 and C81 cell lines compared to ID4 expressing LNCaP cell line. Knockdown of EZH2 in DU145 cell line led to re-expression of ID4 and decrease in enrichment of EZH2, H3K27Me3 and DNMT1 demonstrating that ID4 is regulated in an EZH2 dependent manner. ChIP data on prostate cancer tissue specimens and cell lines suggested EZH2 occupancy and H3K27Me3 marks on the ID4 promoter. Collectively, our data indicate a PRC2 dependent mechanism in ID4 promoter silencing in prostate cancer through recruitment of EZH2 and a corresponding increase in H3K27Me3. Increased EZH2 but decreased ID4 expression in prostate cancer strongly supports this model.

Peritoneal expression of Matrilysin helps identify early post-operative recurrence of colorectal cancer

Recurrence of colorectal cancer (CRC) following a potentially curative resection is a challenging clinical problem. Matrix metalloproteinase-7 (MMP-7) is over-expressed by CRC cells and supposed to play a major role in CRC cell diffusion and metastasis. MMP-7 RNA expression was assessed by real-time PCR using specific primers in peritoneal washing fluid obtained during surgical procedure. After surgery, patients underwent a regular follow up for assessing recurrence. transcripts for MMP-7 were detected in 31/57 samples (54%). Patients were followed-up (range 20-48 months) for recurrence prevention. Recurrence was diagnosed in 6 out of 55 patients (11%) and two patients eventually died because of this. Notably, all the six patients who had relapsed were positive for MMP-7. Sensitivity and specificity of the test were 100% and 49% respectively. Data from patients have also been corroborated by computational approaches. Public available coloncarcinoma datasets have been employed to confirm MMP7 clinical impact on the disease. Interestingly, MMP-7 expression appeared correlated to Tgfb-1, and correlation of the two factors represented a poor prognostic factor. This study proposes positivity of MMP-7 in peritoneal cavity as a novel biomarker for predicting disease recurrence in patients with CRC.

Modeling colorectal cancer using CRISPR-Cas9-mediated engineering of human intestinal organoids

Human colorectal tumors bear recurrent mutations in genes encoding proteins operative in the WNT, MAPK, TGF-β, TP53 and PI3K pathways. Although these pathways influence intestinal stem cell niche signaling, the extent to which mutations in these pathways contribute to human colorectal carcinogenesis remains unclear. Here we use the CRISPR-Cas9 genome-editing system to introduce multiple such mutations into organoids derived from normal human intestinal epithelium. By modulating the culture conditions to mimic that of the intestinal niche, we selected isogenic organoids harboring mutations in the tumor suppressor genes APC, SMAD4 and TP53, and in the oncogenes KRAS and/or PIK3CA. Organoids engineered to express all five mutations grew independently of niche factors in vitro, and they formed tumors after implantation under the kidney subcapsule in mice. Although they formed micrometastases containing dormant tumor-initiating cells after injection into the spleen of mice, they failed to colonize in the liver. In contrast, engineered organoids derived from chromosome-instable human adenomas formed macrometastatic colonies. These results suggest that 'driver' pathway mutations enable stem cell maintenance in the hostile tumor microenvironment, but that additional molecular lesions are required for invasive behavior.

The SOCS-1 -1478CA/del polymorphism is not associated with colorectal cancer or age at onset in Turkish subjects

BACKGROUND

Suppressor of cytokine signaling (SOCS)-1 acts as a key regulator of many cytokine signaling pathways and its abnormal expression has been identified in several human malignancies, suggesting potential roles in carcinogenesis. The aim of this study was to investigate any association between the functional SOCS- 1 -1478CA>del polymorphism and colorectal cancer (CC) as well as age at onset in a Turkish clinical sample.

MATERIALS AND METHODS

A total of 122 subjects were enrolled in this case-control study (70 CC cases and 52 controls). The SOCS-1 -1478CA>del polymorphism was genotyped using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

The odds ratio of the del allele for CC relative to the CA allele was not significantly different between the groups (OR=0.71, 95% CI=0.41-1.22, p=0.27). This result did not change after adjustment for age and sex on multivariable regression analysis (OR=0.84, 95% CI=0.59-1.34, p=0.53). When the SOCS-1 -1478CA>del polymorphism was analyzed among CC patients in relation to the age at disease onset, we found no significant differences between subjects with the del/del, CA/del, and CA/CA genotypes.

CONCLUSIONS

The results of our study did not point towards a major role of the SOCS-1 -1478CA>del polymorphism in the pathogenesis of CC in Turkish subjects.

Transcriptional dynamics in colorectal carcinogenesis: new insights into the role of c-Myc and miR17 in benign to cancer transformation

Colorectal cancer develops in a sequential, evolutionary process, leading to a heterogenic tumor. Comprehensive molecular studies of colorectal cancer have been previously performed; still, the process of carcinogenesis is not fully understood. We utilized gene expression patterns from 94 samples including normal, adenoma, and adenocarcinoma colon biopsies and performed a coexpression network analysis to determine gene expression trajectories of 8,000 genes across carcinogenesis. We found that the majority of gene expression changes occur in the transition from normal tissue to adenoma. The upregulated genes, known to be involved in cellular proliferation, included c-Myc along with its targets. In a cellular model system, we show that physiologic upregulation of c-Myc can lead to cellular proliferation without DNA replication stress. Our analysis also found that carcinogenesis involves a progressive downregulation of genes that are markers of colonic tissue and propose that this reflects a perturbed differentiation of colon cells during carcinogenesis. The analysis of miRNAs targets pointed toward the involvement of miR17 in the regulation of colon cell differentiation. Finally, we found that copy-number variations (CNV) enriched in colon adenocarcinoma tend to occur in genes whose expression changes already in adenoma, with deletions occurring in genes downregulated and duplications in genes upregulated in adenomas. We suggest that the CNVs are selected to reinforce changes in gene expression, rather than initiate them. Together, these findings shed new light into the molecular processes that underlie the transformation of colon tissue from normal to cancer and add a temporal context that has been hitherto lacking.

A gene expression and pre-mRNA splicing signature that marks the adenoma-adenocarcinoma progression in colorectal cancer

It is widely accepted that most colorectal cancers (CRCs) arise from colorectal adenomas (CRAs), but transcriptomic data characterizing the progression from colorectal normal mucosa to adenoma, and then to adenocarcinoma are scarce. These transition steps were investigated using microarrays, both at the level of gene expression and alternative pre-mRNA splicing. Many genes and exons were abnormally expressed in CRAs, even more than in CRCs, as compared to normal mucosae. Known biological pathways involved in CRC were altered in CRA, but several new enriched pathways were also recognized, such as the complement and coagulation cascades. We also identified four intersectional transcriptional signatures that could distinguish CRAs from normal mucosae or CRCs, including a signature of 40 genes differentially deregulated in both CRA and CRC samples. A majority of these genes had been described in different cancers, including FBLN1 or INHBA, but only a few in CRC. Several of these changes were also observed at the protein level. In addition, 20% of these genes (i.e. CFH, CRYAB, DPT, FBLN1, ITIH5, NR3C2, SLIT3 and TIMP1) showed altered pre-mRNA splicing in CRAs. As a global variation occurring since the CRA stage, and maintained in CRC, the expression and splicing changes of this 40-gene set may mark the risk of cancer occurrence from analysis of CRA biopsies.

Mucinous adenocarcinoma of the umbilicus 8 years following anterior resection for villous adenoma of the rectum

We present the case of an 80-year-old retired consultant histopathologist who presented to us with a malignant umbilical mass 8years following resection of a sigmoid adenoma. The report details initial investigation and management of the umbilical mass and the subsequently discovered pelvic recurrence. Our conclusions of its origin, as a malignant transformation due to seeding of the original sigmoid adenoma, show the slow progression of some colorectal tumours; and the importance of obtaining a complete specimen intra-operatively.

Over-expression of COX-2 mRNA in colorectal cancer

BACKGROUND

Cyclooxygenase-2 (COX-2, PTGS2) is an enzyme involved in the synthesis of prostaglandins and thromboxanes, which are regulators of biologic processes such as inflammation, cell proliferation and angiogenesis. COX-2 over-expression was reported in many (pre) malignant tissues, but data strongly vary and seem to depend on the methodology used.

METHODS

Normal colorectal mucosa and paired cancerous tissue from 60 patients with colorectal cancer was investigated for the levels of COX-2 mRNA by real-time quantitative Polymerase Chain Reaction (qPCR). COX-2 levels were expressed relative to either: tissue weight or levels of the housekeeping genes beta-2 microglobulin (B2M) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH).

RESULTS

COX-2 mRNA levels, normalized with respect to tissue weight or mRNA levels of the housekeeping genes B2M or GAPDH, were over-expressed in 80%, 70% and 40% of the colorectal tumor tissues, as compared to the paired adjacent normal colorectal mucosa samples, respectively. Highest mRNA COX-2 ratios tumor/normal were measured when expressed per mg tissue (mean ratio 21.6). When normalized with respect to the housekeeping genes B2M or GAPDH, mean tumor/normal ratios were 16.1 and 7.5, respectively.

CONCLUSION

Expression of COX-2 mRNA levels per mg tissue is most simple in comparison to normalization with respect to the housekeeping genes B2M or GAPDH. Levels of COX-2 mRNA are found over-expressed in almost 80% of the colorectal tumors, compared to paired adjacent normal colorectal mucosa, suggesting a role of COX-2 as a potential biomarker for cancer risk, whereas inhibitors of COX-2 could be of value in chemoprevention of colon cancer.