DNA methylation of microRNA-124a is a potential risk marker of colitis-associated cancer in patients with ulcerative colitis

Promoter methylation levels of microRNA-124 in non-neoplastic rectal mucosa as a potential biomarker for ulcerative colitis-associated colorectal cancer in pediatric-onset patients

PURPOSE

To determine the methylation level of the miR-124 promoter in non-neoplastic rectal mucosa of patients with pediatric-onset ulcerative colitis (UC) to predict UC-associated colorectal cancer (UC-CRC).

METHODS

Between 2005 and 2017, non-neoplastic rectal tissue specimens were collected from 86 patients with UC, including 13 patients with UC-CRC; cancer tissues were obtained from the latter group. The methylation status of the miR-124 promoter was quantified using bisulfite pyrosequencing and compared between pediatric- and adult-onset UC patients.

RESULTS

Patients with pediatric-onset UC experienced a significantly shorter disease duration than those with adult-onset UC. The levels of miR-124 promoter methylation in non-neoplastic rectal mucosa were positively correlated with the age at the diagnosis and duration of UC. The rate of increase in miR-124 methylation was accelerated in patients with pediatric-onset UC compared to those with adult-onset UC. Furthermore, the miR-124 methylation levels in non-neoplastic rectal mucosa were significantly higher in patients with UC-CRC than in those with UC alone (P = 0.02). A receiver operating characteristic analysis revealed that miR-124 methylation in non-neoplastic tissue discriminated between patients with pediatric-onset UC with or without CRC.

CONCLUSION

miR-124 methylation in non-neoplastic rectal mucosa may be a useful biomarker for identifying patients with pediatric-onset UC who face the highest risk of developing UC-CRC.

Epigenetic and metabolic reprogramming in inflammatory bowel diseases: diagnostic and prognostic biomarkers in colorectal cancer

BACKGROUND AND AIM

"Inflammatory bowel disease" (IBD) is a chronic, relapsing inflammatory disease of the intestinal tract that typically begins at a young age and might transit to colorectal cancer (CRC). In this manuscript, we discussed the epigenetic and metabolic change to present a extensive view of IBDs transition to CRC. This study discusses the possible biomarkers for evaluating the condition of IBDs patients, especially before the transition to CRC.

RESEARCH APPROACH

We searched "PubMed" and "Google Scholar" using the keywords from 2000 to 2022.

DISCUSSION

In this manuscript, interesting titles associated with IBD and CRC are discussed to present a broad view regarding the epigenetic and metabolic reprogramming and the biomarkers.

CONCLUSION

Epigenetics can be the main reason in IBD transition to CRC, and Hypermethylation of several genes, such as VIM, OSM4, SEPT9, GATA4 and GATA5, NDRG4, BMP3, ITGA4 and plus hypomethylation of LINE1 can be used in IBD and CRC management. Epigenetic, metabolisms and microbiome-derived biomarkers, such as Linoleic acid and 12 hydroxy 8,10-octadecadienoic acid, Serum M2-pyruvate kinase and Six metabolic genes (NAT2, XDH, GPX3, AKR1C4, SPHK and ADCY5) expression are valuable biomarkers for early detection and transition to CRC condition. Some miRs, such as miR-31, miR-139-5p, miR -155, miR-17, miR-223, miR-370-3p, miR-31, miR -106a, miR -135b and miR-320 can be used as biomarkers to estimate IBD transition to CRC condition.

Microarchitectures of Barrett's esophagus associated with DNA methylation status

Aim: DNA methylation is involved in esophageal adenocarcinoma (EAC) and Barrett's esophagus (BE). Microarchitectures of on-neoplastic BE associated with DNA methylation status were examined using magnifying narrow-band imaging (NBI) endoscopy. Patients and methods: Using biopsies from non-neoplastic BE without cancer (n = 66; N group), with EAC (n = 27; ADJ group) and EAC tissue (n = 22; T group), methylation of N33, DPYS, SLC16A12, miR124a3 and miR34bc genes were quantified. Magnifying NBI features of non-neoplastic BE were classified according to their morphologies. Results: The ADJ and T groups presented higher DNA methylation compared with the N group. Magnifying NBI endoscopic features of non-neoplastic BE also correlated with DNA methylation as an independent factor. Conclusion: Microarchitectures of BE visualized by magnifying NBI endoscopy correlated with DNA methylation.

MicroRNA-29a and MicroRNA-124 as novel biomarkers for hepatocellular carcinoma

BACKGROUND

Numerous microRNAs (miRNAs) have been observed to be abnormally expressed in cancer. Therefore, miRNA signatures could be potential noninvasive diagnostic and prognostic biomarkers for hepatocellular carcinoma (HCC).

AIMS

To correlate miRNA-29a and miRNA-124 expression levels with the clinical features and survival rates of HCC patients.

METHODS

Serum miRNA expression in 150 samples (50 patients with HCC, 50 patients with liver cirrhosis, and 50 healthy controls) were quantified using real-time qRT-PCR.

RESULTS

The expression levels of serum miRNA-29a were higher and the levels of miRNA-124 were lower in patients with HCC than in patients with liver cirrhosis and controls. ROC curve analysis showed promising accuracy for both miRNAs in distinguishing patients with HCC from those with liver cirrhosis. Levels of miRNA-29a were related to tumor number, size, stage, and outcome, whereas levels of miRNA-124 were related to vascular invasion. The overall survival rate of patients with low miRNA-29a expression was significantly higher than that of patients with high expression. Additionally, the multivariate analysis identified miRNA-29a as an independent prognostic variable.

CONCLUSIONS

The investigated miRNAs showed acceptable accuracy in the diagnosis of HCC; therefore, both could be utilized as diagnostic biomarkers. Additionally, miRNA-29a could be used as a prognostic biomarker.

Effects of Kalimeris indica (L.) Sch Bip on colitis-associated colorectal cancer

Kalimeris indica (L.) Sch Bip (K. indica) is a plant of the genus Kalimeris in Asteraceae, and its whole herb can be used as medicine for the treatment of intestinal inflammatory diseases. But the mechanism is not clear. Therefore, this study was designed to explore the mechanism of K. indica (KI) in colitis-associated colorectal cancer. The expression levels of miR-31-5p and proinflammatory factors were detected using THP-1 and Caco2 cells in vitro. KI could rescue the upregulation of miR-31-5p induced by IL-6 and TNF-α in Caco2 and THP-1 cells. In LPS-stimulated PMA-differentiated THP-1 cells, KI restored miR-31-5p expression by downregulating the expression of IL-6 and TNF-α. C57BL/6 mice were used to construct CAC model through the induction of azoxymethane/dextran sulfate sodium. The successfully established CAC mice were treated with water extract of KI through intragastric administration for 5 weeks. The result showed that KI could significantly reduce the atypical hyperplasia in colon tissue, and inhibit the expression of proinflammatory factors such as IL-6, TNF, IL-11, IL-7, etc. At the same time, KI could restore the level of miR-31-5p in mice, and therefore the downstream LATS2 to inhibit the development of CAC. These above results indicate that KI is a potentially effective herb medicine to prevent CAC.

Aberrant methylation of miR-124 upregulates DNMT3B in colorectal cancer to accelerate invasion and migration

The dysregulation of microRNA expression is significantly associated with the initiation and development of CRC. miR-124 is markedly downregulated in colorectal cancer. In the present study, the effects of methylation, over expression and downregulation of miR-124 and its target gene DNMT3B on the proliferation, migration and invasion of colorectal cell line were investigated. The promoter methylation status of miR-124 in the CRC was investigated by methylation specific PCR (MSP). The potential role of miR-124 expression in CRC cells was investigated using the demethylation reagent 5-Aza-CdR and transfection of miR-124 mimic/antimir. MSP revealed that miR-124 promoter region was hypermethylated, result in its significant downregulation in tumour tissues. We showed miR-124 expression was upregulated following 5-AZA-CdR treatment. Transfected Hct-116 cell line with miR-124 leads to decreased DNMT3B expression, cell proliferation, migration and invasion of HCT-116. In conclusion, our data indicate that miR-124 suppress colorectal cancer proliferation, migration and invasion through downregulating DNMT3B level.

Dysregulation of miR-1-3p: An Early Event in Colitis-Associated Dysplasia

Detection of colorectal dysplasia during surveillance colonoscopy remains the best method of determining risk for colitis-associated colorectal cancer (CAC). miRNAs (miRs) show great promise as tissue-specific biomarkers of neoplasia. The goal of this study was to explore the miR expression profile of precancerous dysplastic lesions in the AOM/DSS mouse model and identify early molecular changes associated with CAC. Epithelial cells were laser-microdissected from the colonic mucosa (inflamed versus dysplastic) of mice with AOM/DSS-induced colitis. A miR signature that can distinguish inflamed non-neoplastic mucosa from dysplasia was identified. Bioinformatic analyses led to the discovery of associated miR gene targets and enriched pathways and supported the construction of a network interaction map. miR-1a-3p was one of the miRs with the highest number of predicted targets, including Cdk6. Interestingly, miR-1a-3p and Cdk6 were down- and up-regulated in dysplastic lesions, respectively. Transfection of HCT116 and RKO cells with miR-1a-3p mimics induced apoptosis and cell cycle arrest in G1, suggesting its biological function. A slight reduction in the level of CDK6 transcripts was also observed in cells transfected with miR-1. These data provide novel insight into the early molecular alterations that accompany the development of CAC and identify a miR signature that represents a promising biomarker for the early detection of colitis-associated dysplasia.

DNA methylation changes and inflammaging in aging-associated diseases

Aging as an inevitable phenomenon is associated with pervasive changes in physiological functions. There is a relationship between aging and the increase of several chronic diseases. Most age-related disorders are accompanied by an underlying chronic inflammatory state, as demonstrated by local infiltration of inflammatory cells and greater levels of proinflammatory cytokines in the bloodstream. Within inflammaging, many epigenetic events, especially DNA methylation, change. During the aging process, due to aberrations of DNA methylation, biological processes are disrupted, leading to the emergence or progression of a variety of human diseases, including cancer, neurodegenerative disorders, cardiovascular disease and diabetes. The focus of this review is on DNA methylation, which is involved in inflammaging-related activities, and how its dysregulation leads to human disorders.

MicroRNA Methylome Signature and Their Functional Roles in Colorectal Cancer Diagnosis, Prognosis, and Chemoresistance

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. Despite significant advances in the diagnostic services and patient care, several gaps remain to be addressed, from early detection, to identifying prognostic variables, effective treatment for the metastatic disease, and the implementation of tailored treatment strategies. MicroRNAs, the short non-coding RNA species, are deregulated in CRC and play a significant role in the occurrence and progression. Nevertheless, microRNA research has historically been based on expression levels to determine its biological significance. The exact mechanism underpinning microRNA deregulation in cancer has yet to be elucidated, but several studies have demonstrated that epigenetic mechanisms play important roles in the regulation of microRNA expression, particularly DNA methylation. However, the methylation profiles of microRNAs remain unknown in CRC patients. Methylation is the next major paradigm shift in cancer detection since large-scale epigenetic alterations are potentially better in identifying and classifying cancers at an earlier stage than somatic mutations. This review aims to provide insight into the current state of understanding of microRNA methylation in CRC. The new knowledge from this study can be utilized for personalized health diagnostics, disease prediction, and monitoring of treatment.

From inflammatory bowel disease to colorectal cancer: what's the role of miRNAs?

Inflammatory Bowel Disease (IBD) is a chronic inflammatory disease with relapse and remission periods. Ulcerative colitis and Crohn's disease are two major forms of the disease. IBD imposes a lot of sufferings on the patient and has many consequences; however, the most important is the increased risk of colorectal cancer, especially in patients with Ulcerative colitis. This risk is increased with increasing the duration of disease, thus preventing the progression of IBD to cancer is very important. Therefore, it is necessary to know the details of events contributed to the progression of IBD to cancer. In recent years, the importance of miRNAs as small molecules with 20-22 nucleotides has been recognized in pathophysiology of many diseases, in which IBD and colorectal cancer have not been excluded. As a result, the effectiveness of these small molecules as therapeutic target is hopefully confirmed. This paper has reviewed the related studies and findings about the role of miRNAs in the course of events that promote the progression of IBD to colorectal carcinoma, as well as a review about the effectiveness of some of these miRNAs as therapeutic targets.

MicroRNA expression in inflammatory bowel disease-associated colorectal cancer

MicroRNAs (miRNAs) are non-coding RNA molecules composed of 19–25 nucleotides that regulate gene expression and play a central role in the regulation of several immune-mediated disorders, including inflammatory bowel diseases (IBD). IBD, represented by ulcerative colitis and Crohn’s disease, is characterized by chronic intestinal inflammation associated with an increased risk of colorectal cancer (CRC). CRC is one of the most prevalent tumors in the world, and its main risk factors are obesity, physical inactivity, smoking, alcoholism, advanced age, and some eating habits, in addition to chronic intestinal inflammatory processes and the use of immunosuppressants administered to IBD patients. Recent studies have identified miRNAs associated with an increased risk of developing CRC in this population. The identification of miRNAs involved in this tumorigenic process could be useful to stratify cancer risk development for patients with IBD and to monitor and assess prognosis. Thus, the present review aimed to summarize the role of miRNAs as biomarkers for the diagnosis and prognosis of IBD-associated CRC. In the future, therapies based on miRNA modulation could be used both in clinical practice to achieve remission of the disease and restore the quality of life for patients with IBD, and to identify the patients with IBD at high risk for tumor development.

Construction of methylation-associated nomogram for predicting the recurrence-free survival risk of stage I-III lung adenocarcinoma

Aim: The aim of our study was to investigate a methylation-associated predictor for prognosis in patients with stage I-III lung adenocarcinoma (LUAD). Methods: A DNA methylation-based signature was developed via univariate, least absolute shrinkage and selection operator and multivariate Cox regression models. Results: We identified a 14-site methylation signature that was correlated with recurrence-free survival of stage I-III lung adenocarcinoma patients. By receiver operating characteristic analysis, we showed the high ability of the 14-site methylation signature for predicting recurrence-free survival. In addition, the nomogram result showed a satisfactory predictive value. Conclusion: We successfully identified a DNA methylation-associated nomogram which can predict recurrence-free survival in patients with stage I-III lung adenocarcinoma.

High Diagnostic and Prognostic Value of miRNAs Compared with the Carcinoembryonic Antigen as a Traditional Tumor Marker

A significant challenge in cancer detection and treatment is early diagnosis and accurate prognosis of the disease that enables effective therapies and interventions to improve the patient's condition. Up to now, many parts of research have tended to focus on the carcinoembryonic antigen (CEA) to detect cancers and estimate the survival rates of patients with multiple cancer types, including colorectal, breast, non-small cell lung, and pancreas cancer. Limited sensitivity and specificity of this traditional tumor marker make it an inappropriate biomarker to diagnose cancer, especially in the early stages, while several lines of research have introduced miRNAs as reliable indicators of tumor initiation, development, and therapy response. Indeed, miRNAs have unique properties that provide considerable benefits, such as discriminating benign diseases from malignancies, prediction of cancer possibility and progress, checking sensitivity to treatment, and initial detection of tumors. This review summarizes the relationships between miRNAs and CEA, the diagnostic significance of CEA in combination with miRNAs, and the distinct advantages of miRNAs over CEA as tumor biomarkers. Advancement in our current understanding of miRNAs is essential to discover new and effective biomarkers for diagnostic, prognostic, and therapeutic goals of cancer patients.

Forsythoside A protects against lipopolysaccharide-induced acute lung injury through up-regulating microRNA-124

Acute lung injury (ALI) is a life-threatening disease without effective pharmacotherapies, so far. Forsythia suspensa is frequently used in the treatment of lung infection in traditional Chinese medicine. In search for natural anti-inflammatory components, the activity and the underlying mechanism of Forsythoside A (FA) from Forsythia suspensa were explored. In the present paper, BALB/c mice and murine RAW 264.7 cells were stimulated by LPS to establish inflammation models. Data showed that FA inhibited the production of TNF-α and IL-6 and the activation of STAT3 in LPS-stimulated RAW 264.7 cells. Additionally, FA increased the expression level of microRNA-124 (miR-124). Furthermore, the inhibitory effect of FA on STAT3 was counteracted by the treatment of miR-124 inhibitor. Critically, FA ameliorated LPS-induced ALI pathological damage, the increase in lung water content and inflammatory cytokine, cells infiltration and activation of the STAT3 signaling pathway in BALB/c mice. Meanwhile, FA up-regulated the expression of miR-124 in lungs, while administration with miR-124 inhibitor attenuated the protective effects of FA. Our results indicated that FA alleviates LPS-induced inflammation through up-regulating miR-124 in vitro and in vivo. These findings indicate the potential of FA and miR-124 in the treatment of ALI.

Dissecting miRNA signature in colorectal cancer progression and metastasis

Colorectal cancer (CRC) is the third most common cancer and leading cause of cancer related deaths worldwide. Despite recent advancements in surgical and molecular targeted therapies that improved the therapeutic efficacy in CRC, the 5 years survival rate of CRC patients still remains frustratingly poor. Accumulated evidences indicate that microRNAs (miRNAs) play a crucial role in the progression and metastasis of CRC. Dysregulated miRNAs are closely associated with cancerous phenotypes (e.g. enhanced proliferative and invasive ability, evasion of apoptosis, cell cycle aberration, and promotion of angiogenesis) by regulating their target genes. In this review, we provide an updated overview of tumor suppressive and oncogenic miRNAs, circulatory miRNAs, and the possible causes of dysregulated miRNAs in CRC. In addition, we discuss the important functions of miRNAs in drug resistance of CRC.

Genomic variants associated with the number and diameter of muscle fibers in pigs as revealed by a genome-wide association study

Muscle fiber characteristics comprise a set of complex traits that influence the meat quality and lean meat production of livestock. However, the genetic and biological mechanisms regulating muscle fiber characteristics are largely unknown in pigs. Based on a genome-wide association study (GWAS) performed on 421 Large White × Min pig F2 individuals presenting well-characterized phenotypes, this work aimed to detect genome variations and candidate genes for five muscle fiber characteristics: percentage of type I fibers (FIB1P), percentage of type IIA fibers (FIB2AP), percentage of type IIB fibers (FIB2BP), diameter of muscle fibers (DIAMF) and number of muscle fibers per unit area (NUMMF). The GWAS used the Illumina Porcine SNP60K genotypic data, which were analyzed by a mixed model. Seven and 10 single nucleotide polymorphisms (SNPs) were significantly associated with DIAMF and NUMMF, respectively (P < 1.10E-06); no SNP was significantly associated with FIB1P, FIB2AP or FIB2B. For DIAMF, the significant SNPs on chromosome 4 were located in the previously reported quantitative trait loci (QTL) interval. Because the significant SNPs on chromosome 6 were not mapped in the previously reported QTL interval, a putative novel QTL was suggested for this locus. None of the previously reported QTL intervals on chromosomes 6 and 14 harbored significant SNPs for NUMMF; thus, new potential QTLs on these two chromosomes are suggested in the present work. The most significant SNPs associated with DIAMF (ALGA0025682) and NUMMF (MARC0046984) explained 12.02% and 11.59% of the phenotypic variation of these traits, respectively. In addition, both SNPs were validated as associated with DIAMF and NUMMF in Beijing Black pigs (P < 0.01). Some candidate genes or non-coding RNAs, such as solute carrier family 44 member 5 and miR-124a-1 for DIAMF, and coiled-coil serine rich protein 2 for NUMMF, were identified based on their close location to the significant SNPs. This study revealed some genome-wide association variants for muscle fiber characteristics, and it provides valuable information to discover the genetic mechanisms controlling these traits in pigs.

Extract of Ilex rotunda Thunb alleviates experimental colitis-associated cancer via suppressing inflammation-induced miR-31-5p/YAP overexpression

BACKGROUND

Ilex rotunda Thunb is a traditional medicine used in China treating colitis clinically. Triterpenoids is one of its main components. However, the detailed pharmacological activity and the component responsible for its clinical effects are still elusive.

PURPOSE

To test the in vivo colitis-associated cancer (CAC) preventive effect of the water fraction extracted from the roots of I. rotunda, and to evaluate its microRNA (miRNA)-related mechanism.

STUDY DESIGN AND METHODS

Male or female C57BL/6 mice (12 weeks of age) were used to construct the azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced CAC. 12.5 mg/kg and 25.0 mg/kg of the standardized water extract of I. rotunda (WIR), being equal to 4.29 and 8.58 g of the raw medicine respectively, were adopted to treat the AOM/DSS-induced CAC from the fourth week and continued for 5 weeks. Mice were killed two weeks after the end of the last round of DSS by cervical dislocation.

RESULTS

The chemical analysis of WIR revealed the presence of 21 compounds. The syringing and caffeic acid (1-hydroxyl-4-O-β-D-glucopyranosylprenyl)-ester are the main components of WIR, counting for 8.27% and 5.71% of the water extract respectively. The levels of miR-31-5p were up-regulated in both thp1 and Caco2 cells (p < 0.05) stimulated by either IL-6 or TNF-α, and WIR could restore miR-31-5p levels in the IL-6/TNF-α-stimulated thp-1 and Caco2 cells. Furthermore, WIR decreased TNF-α and IL-6 levels in PMA-differentiated thp-1 cells stimulated by LPS via NF-κB pathway (p < 0.05), suggesting that WIR could restore miR-31-5p expression via down-regulating IL-6 and TNF-α levels. In vivo study showed that oral administration of WIR (25 mg/kg) produced a significant inhibition on the atypical hyperplasia, as well as the release and the expression of IL-6 and TNF-α in the colon tissue. The in vivo transcription of other pro-inflammatory mediators such as iNOS, IL-11, and IL-17A were also attenuated by WIR administration (25 mg/kg, p < 0.05). Meanwhile, WIR (25 mg/kg) restored the miR-31-5p level which was up-regulated in the CAC model group, and ectopic expressions of the miR-31-5p down-stream LATS2 and YAP genes in the hippo pathway were also modulated by the WIR (25 mg/kg) treatment.

CONCLUSION

The present study suggests that WIR exerts intestinal anti-inflammatory and CAC preventive effects in an experimental CAC mouse model. The CAC preventive effect can be attributed to the suppression of hippo pathway activated by the inflammatory cytokines, indicating that WIR can be potentially used as an herbal product for CAC prevention. Therefore, there is an emergent need for further evaluation of the main components in WIR to determine the definite bioactive component responsible for the CAC preventive activity.

MicroRNA-124: An emerging therapeutic target in cancer

MicroRNAs (miRNAs) are noncoding single‐stranded RNAs, approximately 20‐24 nucleotides in length, known as powerful posttranscriptional regulators. miRNAs play important regulatory roles in cellular processes by changing messenger RNA expression and are widely involved in human diseases, including tumors. It has been reported in the literature that miRNAs have a precise role in cell proliferation, programmed cell death, differentiation, and expression of coding genes. MicroRNA‐124 (miR‐124) has reduced exparession in various human neoplasms and is believed to be related to the occurrence, development, and prognosis of malignant tumors. In our review, we focus on the specific molecular functions of miR‐124 and the downstream gene targets in major cancers, which provide preclinical evidence for the treatment of human cancer. Although some obstacles exist, miR‐124 is still attracting intensive research focus as a promising and effective anticancer weapon.

Hypermethylation-mediated inactivation of miR-124 predicts poor prognosis and promotes tumor growth at least partially through targeting EZH2/H3K27me3 in ESCC

Accumulating evidences indicated that some microRNAs (miRNAs) play a critical role during the carcinogenesis. In the present study, we found that miR-124 is down-regulated in esophageal squamous cell carcinoma (ESCC) tissues. Three miR-124 encoding genes, including mir-124-1, mir-124-2, and mir-124-3, harboring CpG islands undergo methylation-mediated miR-124 inactivation in ESCC tissues. The methylation status of all these three genes was negatively associated with the expression of miR-124. The low expression of miR-124 and the hypermethylation of mir-124-1 and mir-124-3 were associated with the clinico-pathological parameters indicating the poor prognosis. In addition, promoter methylation of all three genes plus low expression of miR-124 was the independent poor prognostic marker for ESCC patients. In conclusion, miR-124 may function as a tumor suppressive miRNA, and hypermethylation-mediated inactivation of miR-124 may be useful for a poor prognostic marker for ESCC patients.

miR-124, a potential therapeutic target in colorectal cancer

Recently, miR-124 has been regarded as a critical modulator of colorectal cancer. We here summarize the studies on the role and mechanism of miR-124 in colorectal cancer. They indicate that miR-124 is methylated during carcinogenesis and functions as a tumor-suppressor in colorectal cancer. miR-124 might serve as a potential diagnostic biomarker and therapeutic target in colorectal cancer in the foreseeable future.

Epigenetic Regulation by lncRNAs: An Overview Focused on UCA1 in Colorectal Cancer

Colorectal cancers have become the second leading cause of cancer-related deaths. In particular, acquired chemoresistance and metastatic lesions occurring in colorectal cancer are a major challenge for chemotherapy treatment. Accumulating evidence shows that long non-coding (lncRNAs) are involved in the initiation, progression, and metastasis of cancer. We here discuss the epigenetic mechanisms through which lncRNAs regulate gene expression in cancer cells. In the second part of this review, we focus on the role of lncRNA Urothelial Cancer Associated 1 (UCA1) to integrate research in different types of cancer in order to decipher its putative function and mechanism of regulation in colorectal cancer cells. UCA1 is highly expressed in cancer cells and mediates transcriptional regulation on an epigenetic level through the interaction with chromatin modifiers, by direct regulation via chromatin looping and/or by sponging the action of a diversity of miRNAs. Furthermore, we discuss the role of UCA1 in the regulation of cell cycle progression and its relation to chemoresistance in colorectal cancer cells.

Relevance of MicroRNAs as Potential Diagnostic and Prognostic Markers in Colorectal Cancer

Colorectal cancer (CRC) is currently the third and the second most common cancer in men and in women, respectively. Every year, more than one million new CRC cases and more than half a million deaths are reported worldwide. The majority of new cases occur in developed countries. Current screening methods have significant limitations. Therefore, a lot of scientific effort is put into the development of new diagnostic biomarkers of CRC. Currently used prognostic markers are also limited in assessing the effectiveness of CRC therapy. MicroRNAs (miRNAs) are a promising subject of research especially since single miRNA can recognize a variety of different mRNA transcripts. MiRNAs have important roles in epigenetic regulation of basic cellular processes, such as proliferation, apoptosis, differentiation, and migration, and may serve as potential oncogenes or tumor suppressors during cancer development. Indeed, in a large variety of human tumors, including CRC, significant distortions in miRNA expression profiles have been observed. Thus, the use of miRNAs as diagnostic and prognostic biomarkers in cancer, particularly in CRC, appears to be an inevitable consequence of the advancement in oncology and gastroenterology. Here, we review the literature to discuss the potential usefulness of selected miRNAs as diagnostic and prognostic biomarkers in CRC.

An Overview of Molecular Profiles in Ulcerative Colitis-Related Cancer

Ulcerative colitis (UC) is an independent risk factor of colorectal cancer (CRC). Both genetic and epigentic events induce a unique molecular profile during the development from UC to UC-related CRC (UCRC). These molecular changes play varied roles in DNA repair, immune response, cell metabolism, and interaction with the microbiota during the carcinogenesis process. This review will systmatically discuss the molecular characteristics of UCRC and point out the future perspectives in this research field.

Comprehensive Assessment of the Relationship Between MicroRNA-124 and the Prognostic Significance of Cancer

BACKGROUND

Numerous studies have demonstrated the presence of microRNA-124 abnormalities involving gene expression, methylation, and single nucleotide polymorphism (SNP) in multiple and diverse cancers, but the prognostic value of these abnormalities in cancer remains inconclusive.

OBJECTIVE

The aim of this study is to determine the prognostic value of miR-124 in cancer.

METHODS

We scrutinized the electronic databases and estimate the association between miR-124 expression, methylation and single nucleotide polymorphisms (SNPs), and prognosis in cancers. The pooled hazard ratios with 95% confidence intervals (CIs) for overall survival (OS), and disease-free survival/recurrence-free survival (RFS)/progression-free survival (PFS) were calculated to estimate the effects of miR-124 expression, methylation, and SNPs on cancer prognosis. The Quality in Prognosis Studies and Newcastle-Ottawa Scale were utilized to assess the quality of included studies.

RESULTS

A total of 20 studies involving 3,574 participants were analyzed in evidence synthesis. Our findings showed that the low expression of miR-124 was significantly associated with poor OS (HR = 2.37, 95% CI: 1.91-2.94, P = 0.00; HR = 3.10, 95% CI: 2.04-4.70, P = 0.00) and PFS/RFS (HR = 2.21, 95% CI: 1.50-3.26, P = 0.00; HR = 2.12, 95% CI: 1.20-3.74, P = 0.00). The hyper-methylation of miR-124 was associated with poor OS (HR = 2.09, 95% CI: 1.48-2.95, P = 0.00) and PFS (HR = 3.70, 95% CI: 1.72-7.97, P = 0.00) (Table 3). The patients carrying with Allele C of miR-124 rs5315649 had a worse OS (HR = 1.50, 95% CI: 1.09-2.07, P = 0.00) and PFS (HR = 1.67, 95% CI: 1.20-2.33, P = 0.00) than the carriers with Allele G.

CONCLUSION

The low expression and hyper-methylation of miR-124 was strongly associated with poor prognosis, and genetic variations of miR-124 rs531564 affected prognosis in cancer patients.

Early detection of ulcerative colitis-associated colorectal cancer

Colitis-associated colorectal cancer (CACC) is one of the most serious complications of inflammatory bowel disease (IBD), particularly in ulcerative colitis (UC); it accounts for approximately 15% of all-causes mortality among IBD patients. Because CACC shows a worse prognosis and higher mortality than sporadic colorectal cancer, early detection is critical. Colonoscopy is primarily recommended for surveillance and several advanced endoscopic imaging techniques are emerging. In addition, recent studies have reported on attempts to develop clinically relevant biomarkers for surveillance using various biosamples, which may become high-performance screening tools in the future, so the best approach and technique for cancer surveillance in long-standing UC patients remain under debate. This review gives a comprehensive description and summary about what progress has been made in terms of early CACC detection.

A Panel of Methylated MicroRNA Biomarkers for Identifying High-Risk Patients With Ulcerative Colitis-Associated Colorectal Cancer

BACKGROUND & AIMS

Methylation of specific microRNAs (miRNAs) often occurs in an age-dependent manner, as a field defect in some instances, and may be an early event in colitis-associated carcinogenesis. We aimed to determine whether specific mRNA signature patterns (MIR1, MIR9, MIR124, MIR137, MIR34B/C) could be used to identify patients with ulcerative colitis (UC) who are at increased risk for colorectal neoplasia.

METHODS

We obtained 387 colorectal tissue specimens collected from 238 patients with UC (152 without neoplasia, 17 with dysplasia, and 69 with UC-associated colorectal cancer [UC-CRC]), from 2 independent cohorts in Japan between 2005 and 2015. We quantified methylation of miRNAs by bisulfite pyrosequencing analysis. We analyzed clinical data to determine whether miRNA methylation patterns were associated with age, location, or segment of the colorectum (cecum, transverse colon, and rectum). Differences in tissue miRNA methylation and expression levels were compared among samples and associated with cancer risk using the Wilcoxon, Mann-Whitney, and Kruskal-Wallis tests as appropriate. We performed a validation study of samples from 90 patients without UC and 61 patients with UC-associated dysplasia or cancer to confirm the association between specific methylation patterns of miRNAs in non-tumor rectal mucosa from patients with UC at risk of UC-CRC.

RESULTS

Among patients with UC without neoplasia, rectal tissues had significantly higher levels of methylation levels of MIR1, MIR9, MIR124, and MIR137 than in proximal mucosa; levels of methylation were associated with age and duration of UC in rectal mucosa. Methylation of all miRNAs was significantly higher in samples from patients with dysplasia or CRC compared with samples from patients without neoplasia. Receiver operating characteristic analysis revealed that methylation levels of miRNAs in rectal mucosa accurately differentiated patients with CRC from those without. Methylation of MIR137 in rectal mucosa was an independent risk factor for UC-CRC. Methylation patterns of a set of miRNAs (panel) could discriminate discriminate UC patients with or without dysplasia or CRC in the evaluation cohort (area under the curve, 0.81) and the validation cohort (area under the curve, 0.78).

CONCLUSIONS

In evaluation and validation cohorts, we found specific miRNAs to be methylated in rectal mucosal samples from patients with UC with dysplasia or CRC compared with patients without neoplasms. This pattern also associated with patient age and might be used to identify patients with UC at greatest risk for developing UC-CRC. Our findings provide evidence for a field defect in rectal mucosa from patients with UC-CRC.

Pyrosequencing quantified methylation level of miR-124 predicts shorter survival for patients with myelodysplastic syndrome

Background

Aberrant CpG island methylation has been increasingly recognized as a common event in myelodysplastic syndrome (MDS). To date, most of the previous studies of miR-124 in MDS have focused on epigenetic changes and little is known about the underlying mechanism through which miR-124 regulates CDK6 expression.

Results

In the present study, we employed pyrosequencing analysis to quantify the methylation levels of upstream regions of the miR-124 genes (miR-124-1, miR-124-2 and miR-124-3) in 56 primary MDS patients. We found the three miR-124 genes were methylated in MDS patients. Univariate analysis revealed that the World Health Organization (WHO) classification, marrow blast count, karyotype, International Prognostic Scoring System (IPSS), mean corpuscular volume, as well as high methylation of miR-124-1, miR-124-2 and miR-124-3 were significantly related to overall survival. In leukaemia-free survival, patients who were older and had an advanced WHO classification, high marrow blast counts, high IPSS risk and high methylation of miR-124-1 and miR-124-2 progressed rapidly to acute myeloid leukaemia. Multivariate analysis demonstrated that high methylation of miR-124-3 was an independent factor of overall survival. Median survival of patients with high miR-124-3 methylation was significantly shorter (7.6 months) than patients with low methylation (32.7 months; P = 0.010). A functional study revealed that silencing of miR-124 resulted in upregulation of its target gene, cyclin dependent kinase CDK6, which in turn promoted cell proliferation in the MDS cell line SKM-1.

Conclusions

High methylation of miR-124-3 predicts shorter survival for patients with MDS, which may be a useful prognostic marker in MDS.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-017-0388-5) contains supplementary material, which is available to authorized users.

miR-152 regulated glioma cell proliferation and apoptosis via Runx2 mediated by DNMT1

BACKGROUND

Aberrant DNA methylation is associated with tumor onset and progression. Study has verified that the DNA methylation of miR-152 was mediated in many tumors, but whether it involved in glioblastomas was still unclear.

METHODS

This study enrolled 20 patients with glioma to analyze the expression pattern of miR-152. Real-time PCR and western blot were used to detect the mRNA or protein expression level, respectively. The relationship between miR-152 and runx2 was detected by Luciferase reporter assay. The methylation level of miR-152 was determined by methylation-specific PCR. Cell proliferation and apoptosis were detected by MTT and Annexin-FITC/PI assay.

RESULTS

The expression of miR-152 was down-regulated while the expression of DNMT1 was up-regulated in both glioma tissue and cell lines. MiR-152 was hypermethylated and its expression was negatively correlated with DNMT in glioma cell lines. DNMT1 knockdown promoted the expression of miR-152, however, DNMT1 overexpression suppressed the expression of miR-152. MiR-152 overexpression promoted glioma cell apoptosis while miR-152 knockdown promoted cell proliferation. MiR-152 targets Runx2 to regulate its expression, Runx2 overexpression abolished the effects of miR-152 overexpression.

CONCLUSION

MiR-152 regulated cell proliferation and apoptosis of glioma mediated by Runx2, while the mechanism of down regulated miR-152 in glioma tissues and cells was its hypermethylation.

Role of MiRNAs in Inflammatory Bowel Disease

Inflammatory bowel diseases (IBD), mainly including Crohn's disease and ulcerative colitis, are characterized by chronic inflammation of the gastrointestinal tract. Despite improvements in detection, drug treatment and surgery, the pathogenesis of IBD has not been clarified. A number of miRNAs have been found to be involved in the initiation, development and progression of IBD, and they may have the potential to be used as biomarkers and therapeutic targets. Here, we have summarized the recent advances about the roles of miRNAs in IBD and analyzed the contribution of miRNAs to general diagnosis, differential diagnosis and activity judgment of IBD. Furthermore, we have also elaborated the promising role of miRNAs in IBD-related cancer prevention and prognosis prediction.

Identification of miR‑124a as a novel diagnostic and prognostic biomarker in non‑small cell lung cancer for chemotherapy

Previous studies have suggested that dysregulation of microRNA (miR) −124a is associated with various types of human cancer. However, there are few studies reporting the level of miR-124a expression in non-small cell lung cancer (NSCLC). The present study investigated the association between miR-124a and NSCLC by analyzing the differential expression of miR-124a in NSCLC using the GEO database, as well as subsequently performing reverse transcription-quantitative polymerase chain reaction analysis on 160 NSCLC biopsies, 32 of which were paired with adjacent normal tissues. The results indicated that mir-124a expression levels were decreased in NSCLC tumor biopsies compared with adjacent normal tissues. The overall survival (OS) in patients with a high expression of miR-124a was prolonged relative to patients with low expression of miR-124a. The expression levels of miR-124a were associated with clinical characteristics, including lymph-node metastasis, tumor differentiation, tumor node metastasis (TNM) stage and diameter. Frequently, lymph-node metastasis, TNM stage, diameter and lack of chemotherapy have been associated with a worse prognosis in patients. In addition, the present study identified that high expression of miR-124awith chemotherapy may increase OS. In conclusion, the current study demonstrated that miR-124a was downregulated in NSCLC, and miR-124a was a potential prognostic tumor biomarker response to chemotherapy.

DNA Methylation Mediated Down-Regulation of miR-370 Regulates Cell Growth through Activation of the Wnt/β-Catenin Signaling Pathway in Human Osteosarcoma Cells

MicroRNA-370 (miR-370) has been observed to act as a tumor suppressor through the targeting of different proteins in a variety of tumors. Our previous study indicated that miR-370 was able to target forkhead box protein M1 (FOXM1) to inhibit cell growth and metastasis in human osteosarcoma cells. In this study, we reported that FOXM1 interacted with β-catenin in vitro and in vivo. Similar to FOXM1, critical components of the Wnt signaling pathway, including β-catenin, c-Myc, and Cyclin D1, were also highly expressed in different human osteosarcoma cells lines. Pharmacological inhibition of FOXM1 or β-catenin but not of c-Myc was associated with the increased expression of miR-370. Ectopic expression of miR-370 inhibited the downstream signaling of β-catenin. Moreover, osteosarcoma cells treated with 5-AZA-2'-deoxycytidine (AZA), a DNA methylation inhibitor, exhibited increased levels of miR-370 and decreased levels of β-catenin downstream targets, which resulted in inhibition of cell proliferation and colony formation ability. In conclusion, our results supported a model in which the DNA methylation-mediated down-regulation of miR-370 reduced its inhibitory effect on FOXM1, thereby promoting FOXM1-β-catenin interaction and activating the Wnt/β-Catenin signaling pathway in human osteosarcoma cells.

Serum and tissue markers in colorectal cancer: State of art

Colorectal cancer (CRC) represents one of the most commonly diagnosed cancers worldwide. It is the second leading cause of cancer death in Western Countries. In the last decade, the survival of patients with metastatic CRC has improved dramatically. Due to the advent of new drugs (irinotecan and oxaliplatin) and target therapies (i.e. bevacizumab, cetuximab, panitumab, aflibercept and regorafenib), the median overall survival has risen from about 12 mo in the mid nineties to 30 mo recently. Molecular studies have recently widened the opportunity for testing new possible markers, but actually, only few markers can be recommended for practical use in clinic. In the next future, the hope is to have a complete panel of clinical biomarkers to use in every setting of CRC disease, and at the same time: 1) to receive information about prognostic significance by their expression and 2) to be oriented in the choice of the adequate treatment. Moreover, molecular analyses have shown that the natural history of all CRCs is not the same. Individual patients with same stage tumors may have different long-term prognosis and response to therapy. In addition, some prognostic variables are likely to be more important than others. Here we review the role of serum and tissue markers according to the recently published English literature. This paper is an extension of the article "Biological and clinical markers in colorectal cancer: state of art" by Cappellani A published in Jan 2010.

Reciprocal regulation between microRNAs and epigenetic machinery in colorectal cancer

Epigenetics encompasses changes in DNA methylation, histone and chromatin structure, and non-coding RNAs, specifically microRNA (miRNA) expression. Recent advances in the rapidly evolving field of colorectal cancer (CRC) epigenetics have revealed a complicated network of reciprocal interconnections between miRNAs and other epigenetic machinery. On the one hand, miRNA expression may be regulated by epigenetic mechanisms including DNA methylation and histone modifications. However, miRNAs may affect the epigenetic machinery by directly targeting its enzymatic components. In this study, we focus on the colorectal miRNA expression profile and further illustrate the reciprocal regulation in CRC, with the aim of offering new insights into the strategies of combatting the disease.

Comprehensive DNA Methylation Profiling of Inflammatory Mucosa in Ulcerative Colitis

INTRODUCTION

Aberrant DNA methylation frequently occurs in the inflammatory mucosa in ulcerative colitis (UC) and is involved in UC-related tumorigenesis. We performed comprehensive DNA methylation profiling of the promoter regions of the inflamed rectal mucosae of patients with UC.

DESIGN

The methylation status of the promoter CpG islands (CGIs) of 45 cancer/inflammation or age-related candidate genes and the LINE1 repetitive element were examined in the colonic mucosae of 84 cancer-free patients with UC by bisulfite pyrosequencing. Methylation status of selected genes (DPYS, N33, MIR1247, GSTP1, and SOX11) was also determined in 14 neoplastic lesions (5 with high-grade dysplasia and 9 with carcinoma) and 8 adjacent tissues derived from 12 patients. An Infinium HumanMethylation450 BeadChip array was used to characterize the methylation status of >450,000 CpG sites for 10 patients with UC.

RESULTS

Clustering analysis based on the methylation status of the candidate genes clearly distinguished the inflammatory samples from the noninflammatory samples. The hypermethylation of the promoter CGIs strongly correlated with increased disease duration, which is a known risk factor for the development of colon cancer. Genome-wide methylation analyses revealed a high rate of hypermethylation in the severe phenotype of UC, particularly at the CGIs. Exclusively hypermethylated promoter CGIs in the severe phenotypes were significantly related to genes involved in biosynthetic processes, the regulation of metabolic processes, and nitrogen compound metabolic processes.

CONCLUSION

Our findings suggest the potential utility of DNA methylation as a molecular marker and therapeutic target for UC-related tumorigenesis.

Epigenetic silencing of miR-124 prevents spermine oxidase regulation: implications for Helicobacter pylori-induced gastric cancer

Chronic inflammation contributes to the development of various forms of cancer. The polyamine catabolic enzyme spermine oxidase (SMOX) is induced in chronic inflammatory conditions, including Helicobacter pylori-associated gastritis, where its production of hydrogen peroxide contributes to DNA damage and subsequent tumorigenesis. MicroRNA expression levels are also altered in inflammatory conditions; specifically, the tumor suppressor miR-124 becomes silenced by DNA methylation. We sought to determine if this repression of miR-124 is associated with elevated SMOX activity and concluded that miR-124 is indeed a negative regulator of SMOX. In gastric adenocarcinoma cells harboring highly methylated and silenced mir-124 gene loci, 5-azacytidine treatment allowed miR-124 re-expression and decreased SMOX expression. Overexpression of an exogenous miR-124-3p mimic repressed SMOX mRNA and protein expression as well as H2O2 production by >50% within 24 h. Reporter assays indicated that direct interaction of miR-124 with the 3'-untranslated region of SMOX mRNA contributes to this negative regulation. Importantly, overexpression of miR-124 before infection with H. pylori prevented the induction of SMOX believed to contribute to inflammation-associated tumorigenesis. Compelling human in vivo data from H. pylori-positive gastritis tissues indicated that the mir-124 gene loci are more heavily methylated in a Colombian population characterized by elevated SMOX expression and a high risk for gastric cancer. Furthermore, the degree of mir-124 methylation significantly correlated with SMOX expression throughout the population. These results indicate a protective role for miR-124 through the inhibition of SMOX-mediated DNA damage in the etiology of H. pylori-associated gastric cancer.

miRNA-124 in Immune System and Immune Disorders

In recent years, miR-124 has emerged as a critical modulator of immunity and inflammation. Here, we summarize studies on the function and mechanism of miR-124 in the immune system and immunity-related diseases. They indicated that miR-124 exerts a crucial role in the development of immune system, regulation of immune responses, and inflammatory disorders. It is evident that miR-124 may serve as an informative diagnostic biomarker and therapeutic target in the future.

Novel evidence for an oncogenic role of microRNA-21 in colitis-associated colorectal cancer

OBJECTIVE

miR-21 was found to be overexpressed in the colon tissues and serum of patients with UC and colorectal cancer (CRC); however, the exact roles of miR-21 in colitis-associated CRC remain unclear. The aim of our study was to investigate the biological mechanisms of miR-21 in colitis-associated colon cancer (CAC).

DESIGN

miR-21 expression was examined in the tumours of 62 patients with CRC from China and 37 colitis-associated neoplastic tissues from Japan and Austria. The biological functions of miR-21 were studied using a series of in vitro, in vivo and clinical approaches.

RESULTS

miR-21 levels were markedly upregulated in the tumours of 62 patients with CRC, 22 patients with CAC, and in a mouse model of CAC. Following azoxymethane and dextran sulfate sodium intervention, miR-21-knockout mice showed reduced expression of proinflammatory and procarcinogenic cytokines (interleukin (IL) 6, IL-23, IL-17A and IL-21) and a decrease in the size and number of tumours compared with the control mouse group. The absence of miR-21 resulted in the reduced expression of Ki67 and the attenuated proliferation of tumour cells with a simultaneous increase in E-cadherin and decrease in β-catenin and SOX9 in the tumours of CAC mice. Furthermore, the absence of miR-21 increased the expression of its target gene PDCD4 and subsequently modulated nuclear factor (NF)-κB activation. Meanwhile, miR-21 loss reduced STAT3 and Bcl-2 activation, causing an increase in the apoptosis of tumour cells in CAC mice.

CONCLUSIONS

These observations provide novel evidence for miR-21 blockade to be a key strategy in reducing CAC.

MicroRNA-145 functions as a tumor suppressor by targeting matrix metalloproteinase 11 and Rab GTPase family 27a in triple-negative breast cancer

Although increasing evidence has documented that microRNA-145 (miR-145) acts as a tumor suppressor in breast cancer, its exact role in triple-negative breast cancer (TNBC) remains poorly defined. In this study, the expression of miR-145 in human TNBC cells and samples from 30 patients was analyzed by stem-loop real-time PCR. We found that miR-145 was significantly downregulated in TNBC tissues and cells. Upregulating miR-145 in HCC1937 cells dramatically suppressed cell proliferation and induced G1-phase arrest, whereas MDA-MB-231 cells did not show growth inhibition. MiR-145 exhibited an inhibitory role in cell invasion through the post-transcriptional regulation of the novel targets MMP11 and Rab27a in TNBC cells. Additionally, miR-145 silencing could be reversed by 5-aza-2'-deoxycytidine (DAC). These results demonstrated that miR-145 has an inhibitory role in TNBC malignancy by targeting MMP11 and Rab27a, which might be potential therapeutic and diagnostic targets for TNBC.

MicroRNAs as diagnostic and prognostic biomarkers in colorectal cancer

MicroRNAs (miRNAs) are key regulators involved in various tumors. They regulate cell cycle, apoptosis and cancer stemness, metastasis and chemoresistance by controlling their target gene expressions. Here, we mainly discuss the potential uses of miRNAs in colorectal cancer (CRC) diagnosis. We also shed light on the important corresponding miRNA targets and on the major regulators of miRNAs. Furthermore, we discuss miRNA activity in assessing the prognosis and recurrence of CRC as well as in modulating responsiveness to chemotherapy. Based on the various pro-oncogenic/anti-oncogenic roles of miRNAs, the advantages of a therapeutic strategy based on the delivery of miRNA mimics are also mentioned. Together, miRNA seems to be an excellent tool for effectively monitoring and targeting CRC.

MicroRNAs and Inflammation in Colorectal Cancer

Colorectal cancers (CRC) are known to be related to inflammatory conditions, and inflammatory bowel diseases increase the relative risk for developing CRC. The use of anti-inflammatory drugs prevents the development of colorectal cancer.Several molecular mediators are connecting the pathways that are involved in inflammatory conditions and in carcinogenesis. By the way these pathways are tightly interwoven, with the consequence that a deregulation at the level of any of these molecular mediators can affect the others.MiRNAs are demonstrated to be deregulated in inflammatory bowel diseases and in colorectal cancer. Moreover, they target several molecular mediators that connect inflammation to cancer, and they are thus implicated in the route from inflammation to colorectal cancer.This chapter will focus on the miRNAs that are jointly deregulated in inflammatory bowel disease and in colorectal cancer. Their role on the regulation of the molecular mediators and pathways that link inflammation to cancer will be described.

Site-Specific MicroRNA Expression May Lead to Different Subtypes in Ulcerative Colitis

Background and Aim

Ulcerative Colitis (UC) is a type of inflammatory bowel disease, considered as an important disease of gastrointestinal tract having a huge impact on the health of the patient. Prolonged inflammation of colon in UC patients increases the risk of developing colorectal cancer. MiRNA are reported as a connecting link between inflammation and cancer. Differential miRNA expression is reported in Crohn’s disease (CD) patients involving various regions of the gastrointestinal tract. The current study was performed to dissect out the site specific miRNA expression in the colon biopsy samples of UC patients from Northern India.

Methods

Biopsy samples were collected from UC patients and healthy controls from Rectosigmoid Area (RS) and Ascending Colon (AC). MiRNA expression was compared between patients with RS and AC using a microarray platform. Differential expression was further validated by Real Time PCR analysis. Demographic and pathological data of UC -associated CRC patients was collected from the hospital database and analyzed for assessing the site of cancer.

Results

Upon analysis of data generated on a microarray platform and qRT PCR revealed that the expression of six miRNAs hsa-miR-146b-5p, hsa-miR-335-3p, hsa-miR-342-3p, hsa-miR-644b-3p, hsa-miR-491-3p, hsa-miR-4732-3p were downregulated in patients where RS was involved as compared to AC. The expression of hsa-miR-141-3p was upregulated in patients where RS region was involved as compared to AC. Analysis of the registered UC patient’s database from the hospital revealed that the site of CRC was predomimnantly the rectosigmoid region of the colon in most of the cases.

Conclusion

This is the first study to show the differential expression of miRNA involving different sites of colon in UC patients. Taking our data and previous reports into consideration, we propose that differential miRNA expression during UC perhaps contribute in the development of UC-associated CRC at the rectosigmoid area.

Longitudinal Study of DNA Methylation of Inflammatory Genes and Cancer Risk

BACKGROUND

Chronic inflammation plays a key role in cancer etiology. DNA methylation modification, one of the epigenetic mechanisms regulating gene expression, is considered a hallmark of cancer. Human and animal models have identified numerous links between DNA methylation and inflammatory biomarkers. Our objective was to prospectively and longitudinally examine associations between methylation of four inflammatory genes and cancer risk.

METHODS

We included 795 Normative Aging Study participants with blood drawn one to four times from 1999 to 2012 (median follow-up, 10.6 years). Promoter DNA methylation of IL6, ICAM-1, IFN, and TLR2 in blood leukocytes was measured using pyrosequencing at multiple CpG sites and averaged by gene for data analysis. We used Cox regression models to examine prospective associations of baseline and time-dependent methylation with cancer risk and compared mean methylation differences over time between cancer cases and cancer-free participants.

RESULTS

Baseline IFN hypermethylation was associated with all-cancer (HR, 1.49; P = 0.04) and prostate cancer incidence (HR, 1.69; P = 0.02). Baseline ICAM-1 and IL6 hypermethylation were associated with prostate cancer incidence (HR, 1.43; P = 0.02; HR, 0.70; P = 0.03, respectively). In our time-dependent analyses, IFN hypermethylation was associated with all-cancer (HR, 1.79; P = 0.007) and prostate cancer (HR, 1.57; P = 0.03) incidence; and ICAM-1 and IL6 hypermethylation were associated with prostate cancer incidence (HR, 1.39; P = 0.02; HR, 0.69; P = 0.03, respectively). We detected significant ICAM-1 hypermethylation in cancer cases (P = 0.0003) 10 to 13 years prediagnosis.

CONCLUSION

Hypermethylation of IFN and ICAM-1 may play important roles in early carcinogenesis, particularly that of prostate cancer.

IMPACT

These methylation changes could inform the development of early detection biomarkers and potential treatments of inflammation-related carcinogenesis.

MicroRNAs as Regulator of Signaling Networks in Metastatic Colon Cancer

MicroRNAs (miRNAs) are a class of small, noncoding RNA molecules capable of regulating gene expression translationally and/or transcriptionally. A large number of evidence have demonstrated that miRNAs have a functional role in both physiological and pathological processes by regulating the expression of their target genes. Recently, the functionalities of miRNAs in the initiation, progression, angiogenesis, metastasis, and chemoresistance of tumors have gained increasing attentions. Particularly, the alteration of miRNA profiles has been correlated with the transformation and metastasis of various cancers, including colon cancer. This paper reports the latest findings on miRNAs involved in different signaling networks leading to colon cancer metastasis, mainly focusing on miRNA profiling and their roles in PTEN/PI3K, EGFR, TGFβ, and p53 signaling pathways of metastatic colon cancer. The potential of miRNAs used as biomarkers in the diagnosis, prognosis, and therapeutic targets in colon cancer is also discussed.

Ulcerative colitis-associated colorectal cancer

The association between ulcerative colitis (UC) and colorectal cancer (CRC) has been acknowledged. One of the most serious and life threatening consequences of UC is the development of CRC (UC-CRC). UC-CRC patients are younger, more frequently have multiple cancerous lesions, and histologically show mucinous or signet ring cell carcinomas. The risk of CRC begins to increase 8 or 10 years after the diagnosis of UC. Risk factors for CRC with UC patients include young age at diagnosis, longer duration, greater anatomical extent of colonic involvement, the degree of inflammation, family history of CRC, and presence of primary sclerosing cholangitis. CRC on the ground of UC develop from non-dysplastic mucosa to indefinite dysplasia, low-grade dysplasia, high-grade dysplasia and finally to invasive adenocarcinoma. Colonoscopy surveillance programs are recommended to reduce the risk of CRC and mortality in UC. Genetic alterations might play a role in the development of UC-CRC. 5-aminosalicylates might represent a favorable therapeutic option for chemoprevention of CRC.