High levels of microRNA-21 in the stroma of colorectal cancers predict short disease-free survival in stage II colon cancer patients. Clin Exp Metastasis. 2011;28:27-38. [PMID: 21069438 PMCID: PMC2998639 DOI: 10.1007/s10585-010-9355-7]

The Encapsulation Strategies for Targeted Delivery of Probiotics in Preventing and Treating Colorectal Cancer: A Review

Colorectal cancer (CRC) ranks as the third most prevalent cancer worldwide. It is associated with imbalanced gut microbiota. Probiotics can help restore this balance, potentially reducing the risk of CRC. However, the hostile environment and constant changes in the gastrointestinal tract pose significant challenges to the efficient delivery of probiotics to the colon. Traditional delivery methods are often insufficient due to their low viability and lack of targeting. To address these challenges, researchers are increasingly focusing on innovative encapsulation technologies. One such approach is single-cell encapsulation, which involves applying nanocoatings to individual probiotic cells. This technique can improve their resistance to the harsh gastrointestinal environment, enhance mucosal adhesion, and facilitate targeted release, thereby increasing the effectiveness of probiotic delivery. This article reviews the latest developments in probiotic encapsulation methods for targeted CRC treatment, emphasizing the potential benefits of emerging single-cell encapsulation techniques. It also analyzes and compares the advantages and disadvantages of current encapsulation technologies. Furthermore, it elucidates the underlying mechanisms through which probiotics can prevent and treat CRC, evaluates the efficacy and safety of probiotics in CRC treatment and adjuvant therapy, and discusses future directions and potential challenges in the targeted delivery of probiotics for CRC treatment and prevention.

MicroRNAs in the Diagnosis of Digestive Diseases: A Comprehensive Review

MicroRNAs (miRNAs) have emerged as crucial regulators in digestive pathologies, including inflammatory bowel disease (miR-31, miR-155, and miR-21), colorectal cancer (miR-21, miR-598, and miR-494), and non-alcoholic fatty liver disease (miR-21, miR-192, and miR-122). Their capacity to modulate gene expression at the post-transcriptional level makes them highly promising candidates for biomarkers and therapeutic interventions. However, despite considerable progress, their clinical application remains challenging. Research has shown that miRNA expression is highly dynamic, varying across patients, disease stages, and different intestinal regions. Their dual function as both oncogenes and tumor suppressors further complicates their therapeutic use, as targeting miRNAs may yield unpredictable effects. Additionally, while miRNA-based therapies hold great potential, significant hurdles persist, including off-target effects, immune activation, and inefficiencies in delivery methods. The intricate interplay between miRNAs and gut microbiota adds another layer of complexity, influencing disease mechanisms and treatment responses. This review examined the role of miRNAs in digestive pathologies, emphasizing their diagnostic and therapeutic potential. While they offer new avenues for disease management, unresolved challenges underscore the need for further research to refine their clinical application.

Identification of miR-141 as a Regulator of Epidermal Homeostasis

MicroRNAs, small endogenous noncoding RNAs, are involved in the regulation of epidermal homeostasis. Among them, miR-203 was the most described and expressed in human epidermis, promoting keratinocyte (KC) differentiation by repressing genes involved in proliferation. To identify other microRNAs involved in this process, the miRNomes of normal human KCs cultured in monolayer (2-dimensional) or in 3-dimensional reconstructed skin were compared. Besides miR-203, miR-141 was one of the most expressed microRNAs in 3-dimensional culture and was overexpressed in 3-dimensional versus 2-dimensional condition, that is, during KC differentiation. Functional experiments revealed that, mostly expressed in the basal layer, miR-141 decreased KC proliferation and clonogenicity while promoting differentiation. Target prediction algorithm coupled with transcriptomic data of KCs overexpressing miR-141 as well as 3' untranslated region luciferase assays highlighted CCND2 mRNA as a direct target of miR-141, leading to its downregulation by miR-141 overexpression. Finally, CCND2 silencing decreased KC proliferation and induced differentiation, revealing that miR-141 action was mediated by CCND2. MiR-141 features were also compared with those of miR-203 in parallel experiments. Although miR-141 displayed functions similar to those of miR-203, it exhibited different localization and targets, suggesting a joint participation of miR-141 and miR-203 in engaging and maintaining KC toward differentiation, respectively.

The Regulation of MicroRNA-21 by Interleukin-6 and Its Role in the Development of Fibrosis in Endometriotic Lesions

Endometriosis is one of the most common causes of chronic pelvic pain and infertility that affects 10% of women of reproductive age. It is currently defined as the presence of endometrial epithelial and stromal cells at ectopic sites; however, advances in endometriosis research have some authors believing that endometriosis should be re-defined as "a fibrotic condition in which endometrial stroma and epithelium can be identified". microRNAs (miRNAs) are regulatory molecules that potentially play a role in endometriotic lesion development. There is evidence that suggests that miRNAs, including microRNA-21 (miR-21), participate in fibrotic processes in different organs, including the heart, kidney, liver and lungs. The objective of this study was to understand the role of miR-21 and the mechanisms that can contribute to the development of fibrosis by determining how IL-6 regulates miR-21 expression and how this miRNA regulates the transforming growth factor beta (TGF-β) signaling pathway to promote fibrosis. We investigated the expression of miR-21 in the baboon and mouse model of endometriosis and its correlation with fibrosis. We demonstrated that inflammation and fibrosis are present at a very early stage of endometriosis and that the inflammatory environment in the peritoneal cavity, which includes interleukin 6 (IL-6), can regulate the expression of miR-21 in vitro and in vivo.

Sensitive Multiplexed MicroRNA Spatial Profiling and Data Classification Framework Applied to Murine Breast Tumors

MicroRNAs (miRNAs) are small RNAs that are often dysregulated in many diseases, including cancers. They are highly tissue-specific and stable, thus, making them particularly useful as biomarkers. As the spatial transcriptomics field advances, protocols that enable highly sensitive and spatially resolved detection become necessary to maximize the information gained from samples. This is especially true of miRNAs where the location their expression within tissue can provide prognostic value with regard to patient outcome. Equally as important as detection are ways to assess and visualize the miRNA's spatial information in order to leverage the power of spatial transcriptomics over that of traditional nonspatial bulk assays. We present a highly sensitive methodology that simultaneously quantitates and spatially detects seven miRNAs in situ on formalin-fixed paraffin-embedded tissue sections. This method utilizes rolling circle amplification (RCA) in conjunction with a dual scanning approach in nanoliter well arrays with embedded hydrogel posts. The hydrogel posts are functionalized with DNA probes that enable the detection of miRNAs across a large dynamic range (4 orders of magnitude) and a limit of detection of 0.17 zeptomoles (1.7 × 10-4 attomoles). We applied our methodology coupled with a data analysis pipeline to K14-Cre Brca1f/fTp53f/f murine breast tumors to showcase the information gained from this approach.

Current evidence regarding the cellular mechanisms associated with cancer progression due to cardiovascular diseases

Several large cohort studies in cardiovascular disease (CVD) patients have shown an increased incidence of cancer. Previous studies in a myocardial infarction (MI) mouse model reported increased colon, breast, and lung cancer growth. The potential mechanisms could be due to secreted cardiokines and micro-RNAs from pathological hearts and immune cell reprogramming. A study in a MI-induced heart failure (HF) mouse demonstrated an increase in cardiac expression of SerpinA3, resulting in an enhanced proliferation of colon cancer cells. In MI-induced HF mice with lung cancer, the attenuation of tumor sensitivity to ferroptosis via the secretion of miR-22-3p from cardiomyocytes was demonstrated. In MI mice with breast cancer, immune cell reprogramming toward the immunosuppressive state was shown. However, a study in mice with renal cancer reported no impact of MI on tumor growth. In addition to MI, cardiac hypertrophy was shown to promote the growth of breast and lung cancer. The cardiokine potentially involved, periostin, was increased in the cardiac tissue and serum of a cardiac hypertrophy model, and was reported to increase breast cancer cell proliferation. Since the concept that CVD could influence the initiation and progression of several types of cancer is quite new and challenging regarding future therapeutic and preventive strategies, further studies are needed to elucidate the potential underlying mechanisms which will enable more effective risk stratification and development of potential therapeutic interventions to prevent cancer in CVD patients.

Inhibitory effect of microRNA-21 on pathways and mechanisms involved in cardiac fibrosis development

Cardiac fibrosis is a pivotal cardiovascular disease (CVD) process and represents a notable health concern worldwide. While the complex mechanisms underlying CVD have been widely investigated, recent research has highlighted microRNA-21's (miR-21) role in cardiac fibrosis pathogenesis. In this narrative review, we explore the molecular interactions, focusing on the role of miR-21 in contributing to cardiac fibrosis. Various signaling pathways, such as the RAAS, TGF-β, IL-6, IL-1, ERK, PI3K-Akt, and PTEN pathways, besides dysregulation in fibroblast activity, matrix metalloproteinases (MMPs), and tissue inhibitors of MMPs cause cardiac fibrosis. Besides, miR-21 in growth factor secretion, apoptosis, and endothelial-to-mesenchymal transition play crucial roles. miR-21 capacity regulatory function presents promising insights for cardiac fibrosis. Moreover, this review discusses numerous approaches to control miR-21 expression, including antisense oligonucleotides, anti-miR-21 compounds, and Notch signaling modulation, all novel methods of cardiac fibrosis inhibition. In summary, this narrative review aims to assess the molecular mechanisms of cardiac fibrosis and its essential miR-21 function.

Identification and functional validation of SRC and RAPGEF1 as new direct targets of miR-203, involved in regulation of epidermal homeostasis

The epidermis is mostly composed of keratinocytes and forms a protecting barrier against external aggressions and dehydration. Epidermal homeostasis is maintained by a fine-tuned balance between keratinocyte proliferation and differentiation. In the regulation of this process, the keratinocyte-specific miR-203 microRNA is of the outmost importance as it promotes differentiation, notably by directly targeting and down-regulating mRNA expression of genes involved in keratinocyte proliferation, such as ΔNp63, Skp2 and Msi2. We aimed at identifying new miR-203 targets involved in the regulation of keratinocyte proliferation/differentiation balance. To this end, a transcriptome analysis of human primary keratinocytes overexpressing miR-203 was performed and revealed that miR-203 overexpression inhibited functions like proliferation, mitosis and cell cycling, and activated differentiation, apoptosis and cell death. Among the down-regulated genes, 24 putative target mRNAs were identified and 8 of them were related to proliferation. We demonstrated that SRC and RAPGEF1 were direct targets of miR-203. Moreover, both were down-regulated during epidermal morphogenesis in a 3D reconstructed skin model, while miR-203 was up-regulated. Finally silencing experiments showed that SRC or RAPGEF1 contributed to keratinocyte proliferation and regulated their differentiation. Preliminary results suggest their involvement in skin carcinoma hyperproliferation. Altogether this data indicates that RAPGEF1 and SRC could be new mediators of miR-203 in epidermal homeostasis regulation.

Role of miR-21 in the diagnosis of colorectal cancer: Meta-analysis and bioinformatics

Advanced colorectal cancer (CRC) has a bad prognosis and is challenging to cure. Therefore, there is an urgent need for an effective early diagnosis marker. MicroRNA-21 (miR-21) regulates the expression of multiple cancer target genes. The objective of this study was to assess the diagnostic role of miR-21 in CRC.A meta-analysis of PubMed, Cochrane Library, EMBASE, and Web of Science databases was performed with a carefully designed search strategy to identify records related to the diagnostic role of miR-21 in CRC. TCGA data was used to search for different microRNAs in colorectal cancer samples and surrounding tissues. In addition, potential target genes for miR-21 were predicted and evaluated by functional analysis. We conducted a meta-analysis for 10 studies, including 728 blood samples of patients with CRC and 472 healthy controls. The combined sensitivity and specificity of miR-21 to diagnose colorectal cancer were 0.79 (95% CI: 0.67-0.87) and 0.92 (95% CI: 0.85-0.96), respectively. The combined positive likelihood ratio (PLR) was 10.20 (95% CI: 4.8-21.5), the combined negative likelihood ratio (NLR) was 0.23 (95% CI: 0.14-0.37), the diagnostic odds ratio (DOR) was 45.00 (95% CI:15-132), the area under the summary receiver operating characteristic curve (SROC) for the included studies was 0.93(95%CI: 0.91-0.95). Simultaneously, TCGA data showed that miR-21 was a differential microRNA in colorectal cancer tissues and adjacent tissues, and it was an up-regulated gene. After verification by three databases, 48 target genes of miR-21 were obtained. Through GO enrichment analysis, it was found that the target genes were mainly distributed in the fiber center, the molecular function was mainly focused on cytokine receptor binding, and the biological process was mainly focused on ubiquitin-dependent protein catabolism mediated by the proteasome. KEGG pathway analysis showed that the target genes were mainly distributed in tumor pathways.

Two oncomiRs, miR-182-5p and miR-103a-3p, Involved in Intravenous Leiomyomatosis

Leiomyomas, also referred to as fibroids, belong to the most common type of benign tumors developing in the myometrium of the uterus. Intravenous leiomyomatosis (IVL) tends to be regarded as a rare type of uterine leiomyoma. IVL tumors are characterized by muscle cell masses developing within the uterine and extrauterine venous system. The underlying mechanism responsible for the proliferation of these lesions is still unknown. The aim of the study was to investigate the expression of the two epigenetic factors, oncomiRs miR-182-5p and miR-103a-3p, in intravenous leiomyomatosis. This study was divided into two stages: initially, miR-182-5p and miR-103a-3p expression was assessed in samples coming from intravenous leiomyomatosis localized in myometrium (group I, n = 6), intravenous leiomyomatosis beyond the uterus (group II; n = 5), and the control group, i.e., intramural leiomyomas (group III; n = 9). The expression level of miR-182-5p was significantly higher in samples coming from intravenous leiomyomatosis (group I and group II) as compared to the control group (p = 0.029 and p = 0.024, respectively). In the second part of the study, the expression levels of the studied oncomiRs were compared between seven samples delivered from one woman during a four-year observation. The long-term follow-up of one patient demonstrated significantly elevated levels of both studied oncomiRs in intravenous leiomyomatosis in comparison to intramural leiomyoma samples.

Expression of Selected miRNAs in Normal and Cancer-Associated Fibroblasts and in BxPc3 and MIA PaCa-2 Cell Lines of Pancreatic Ductal Adenocarcinoma

Therapy for pancreatic ductal adenocarcinoma remains challenging, and the chances of a complete cure are very limited. As in other types of cancer, the expression and role of miRNAs in controlling the biological properties of this type of tumor have been extensively studied. A better insight into miRNA biology seems critical to refining diagnostics and improving their therapeutic potential. In this study, we focused on the expression of miR-21, -96, -196a, -210, and -217 in normal fibroblasts, cancer-associated fibroblasts prepared from a ductal adenocarcinoma of the pancreas, and pancreatic carcinoma cell lines. We compared these data with miRNAs in homogenates of paraffin-embedded sections from normal pancreatic tissues. In cancer-associated fibroblasts and cancer cell lines, miRNAs differed significantly from the normal tissue. In detail, miR-21 and -210 were significantly upregulated, while miR-217 was downregulated. Similar transcription profiles were earlier reported in cancer-associated fibroblasts exposed to hypoxia. However, the cells in our study were cultured under normoxic conditions. We also noted a relation to IL-6 production. In conclusion, cultured cancer-associated fibroblasts and carcinoma cells reflect miR-21 and -210 expression similarly to the cancer tissue samples harvested from the patients.

Prognostic implications of microRNA-21 overexpression in pancreatic ductal adenocarcinoma: an international multicenter study of 686 patients

Despite progress in genomic characterization, no single prognostic marker that can be evaluated using an easy-to-perform and relatively inexpensive method is available for pancreatic ductal adenocarcinoma (PDAC). MicroRNAs, which are stable, tumor- and tissue-specific molecules, are potentially ideal biomarkers, and we established an inter-laboratory validated method to investigate miR-21 as a prognostic biomarker in PDAC. The study samples of PDAC patients were recruited from a test cohort of Glasgow (n = 189) and three validation cohorts of Pisa (n = 69), Sydney (n = 249), and International Cancer Genome Consortium (ICGC) (n = 249). Tissue microarrays were used for miR-21 staining by chromogenic in situ hybridization (CISH). The patients were subdivided into no/low and high miR-21 staining groups using a specific histoscore. Furthermore, miR-21 staining was evaluated against clinicopathological variables and follow-up data by Fisher/log-rank test and Cox proportional models. The prognostic variables found to be significant in univariate analysis (P value < 0.10) were included in multivariate analysis in a backward-stepwise fashion. MiR-21 expression was cytoplasmic, with more consistent staining in the malignant ductal epithelium than in the stroma. The expression of miR-21 was significantly associated with tumor size and lymph node metastasis, whereas no association was observed with other clinicopathological variables. High miR-21 staining (histoscore ≥ 45 [median score]) was an independent predictor of survival in the Glasgow test cohort (HR 2.37, 95% CI: 1.42-3.96, P < 0.0001) and three validation cohorts (Pisa, HR 2.03, 95% CI: 1.21-3.39, P = 0.007; Sydney, HR 2.58, 95% CI (1.21-3.39), P < 0.0001; and ICGC, HR 3.34, 95% CI: 2.07-5.84, P = 0.002) when adjusted for clinical variables in a multivariate model. In comparison to the patients with low miR-21, the patients with high miR-21 expression had significant increase in OS as they benefit from gemcitabine-based adjuvant chemotherapy (Glasgow 16.5 months [with chemotherapy] vs 10.5 months [without chemotherapy]); Sydney 25.0 vs 10.6; ICGC 25.2 vs 11.9. These results indicated that miR-21 is a predictor of survival, prompting prospective trials. Evaluation of miR-21 offers new opportunities for the stratification of patients with PDAC and might facilitate the implementation of clinical management and therapeutic interventions for this devastating disease.

Diagnostic role of circulating MiR-21 in colorectal cancer: a update meta-analysis

AIM

MicroRNA-21 is an oncogenic miRNA that modulates the expression of multiple cancer-related target genes. We conducted this meta-analysis to assess diagnostic role of circulating miR-21 in CRC, hoping to choose the best biomarker in CRC diagnosis.

METHODS

We searched the PubMed, CNKI and WanFang database to identify records related to diagnostic role of circulating miR-21 in CRC. The search words were "microRNA-21", "miRNA-21", "colorectal cancer", "colorectal carcinoma" and "diagnosis". The searched articles were published before 14th July 2020.

RESULTS

We got 18 studies to conduct this meta-analysis including 1129 blood specimens of CRC patients and 951 control specimens. The meta-analysis showed that the pooled sensitivity and specificity of circulating miR-21 for CRC diagnosis were 77% (95% CI, 70-82) and 83% (95% CI, 78-88). The combined positive likelihood ratio (PLR) was 4.20 (95% CI, 3.12-5.66) and the combined negative likelihood ratio(NLR) was 0.30 (95% CI, 0.23-0.38). The diagnostic odds ratio (DOR) was 16.48 (95% CI 10.09-26.91) and the area under the summary receiver operating characteristic curve (SROC) for the included studies was 0.87(95%CI, 0.84-0.90).

CONCLUSION

Our meta-analysis results suggest that circulating miR-21 has a potential diagnostic value with moderate sensitivity and good specificity for CRC.

microRNA-based diagnostic and therapeutic applications in cancer medicine

It has been almost two decades since the first link between microRNAs and cancer was established. In the ensuing years, this abundant class of short noncoding regulatory RNAs has been studied in virtually all cancer types. This tremendously large body of research has generated innovative technological advances for detection of microRNAs in tissue and bodily fluids, identified the diagnostic, prognostic, and/or predictive value of individual microRNAs or microRNA signatures as potential biomarkers for patient management, shed light on regulatory mechanisms of RNA-RNA interactions that modulate gene expression, uncovered cell-autonomous and cell-to-cell communication roles of specific microRNAs, and developed a battery of viral and nonviral delivery approaches for therapeutic intervention. Despite these intense and prolific research efforts in preclinical and clinical settings, there are a limited number of microRNA-based applications that have been incorporated into clinical practice. We review recent literature and ongoing clinical trials that highlight most promising approaches and standing challenges to translate these findings into viable microRNA-based clinical tools for cancer medicine. This article is categorized under: RNA in Disease and Development > RNA in Disease.

microRNAs: Small molecules with a large impact on colorectal cancer

Colorectal cancer (CRC) accounts for one of the main cancer-related mortality and morbidity worldwide. The molecular mechanisms of CRC development have been broadly investigated and, over the last decade, it has become evident that aberrant transcription of microRNAs (miRNAs), a class of small, noncoding RNA molecules, has a significant role in the inception and promotion of CRC. In the involved tissues of CRC, the transcription profile of miRNAs is modulated, and their expression templates are related with prognosis, diagnosis, and treatment outcomes. Here, in the current review, we attempted to discuss the latest information regarding the aberrantly expressed miRNAs in CRC and the advantages of utilizing miRNAs as biomarkers for early diagnosis and prognosis of CRC as well as potential therapeutic application. The effect of miRNAs involved in various signaling pathways, primarily p53, EGFR, Wnt, and TGF-β pathways, was clarified.

MiR-21 in the Cancers of the Digestive System and Its Potential Role as a Diagnostic, Predictive, and Therapeutic Biomarker

MicroRNAs (miRNAs) are small non-coding RNAs. They can regulate the expression of their target genes, and thus, their dysregulation significantly contributes to the development of cancer. Growing evidence suggests that miRNAs could be used as cancer biomarkers. As an oncogenic miRNA, the roles of miR-21 as a diagnostic and prognostic biomarker, and its therapeutic applications have been extensively studied. In this review, the roles of miR-21 are first demonstrated via its different molecular networks. Then, a comprehensive review on the potential targets and the current applications as a diagnostic and prognostic cancer biomarker and the therapeutic roles of miR-21 in six different cancers in the digestive system is provided. Lastly, a brief discussion on the challenges for the use of miR-21 as a therapeutic tool for these cancers is added.

Regulation of microRNA-21 expression by natural products in cancer

Natural products have been of much interest in research studies owing to their wide pharmacological applications, chemical diversity, low side effects, and multitarget activities. Examples of these compounds include matrine, sulforaphane, silibinin, curcumin, berberin, resveratrol, and quercetin. Some of the present anticancer drugs, such as taxol, vincristine, vinblastine, and doxorubicin are also derived from natural products. The anti-carcinogenic effects of these products are partly mediated through modulation of microRNA-21 (miR-21) expression. To date, numerous downstream targets of miR-21 have been recognized, which include phosphatase and tensin homolog (PTEN), ras homolog gene family member B (RHOB), phosphoinositide 3-kinase/protein kinase B (PI3K/Akt), programmed cell death 4 (PDCD4), signal transducer and activator of transcription (STAT)-3, and nuclear factor kappa B (NF-κB) pathways. These signaling pathways, their regulation by oncomiR-21 in cancer, and the modulating impact of natural products are the main focus of this review.

MicroRNA In Situ Hybridization in Paraffin-Embedded Cultured Cells

MicroRNA-21 (miR-21) is one of the most abundant microRNAs in cancer tissues and is considered a strong prognostic biomarker. In situ hybridization (ISH) analyses using locked nucleic acid (LNA) probes have shown that miR-21 is expressed in stromal fibroblastic cells and in subsets of cancer cells. Image analysis of the miR-21 ISH signal has shown that increased expression estimate is associated with poor prognosis in colon cancer. However, assessment of the ISH signal by image analysis to obtain quantitative estimates has been done in retrospective studies without normalization of the expression estimates to reference parameters. The ISH signal output is sensitive to several experimental parameters, including hybridization temperature, probe concentration, and pretreatment, and therefore improved standardized procedures are warranted. We considered the use of paraffin-embedded cultured cells (PECCs) as reference standards that potentially can accompany staining of clinical cancer samples. We found that the cancer cell lines HT-29, CACO-2, and HeLa cells express miR-21 when measured by ISH, and used those cell lines to obtain PECCs. In this methods chapter we present a fixation and embedding procedure to obtain PECCs suitable for microRNA ISH and a double-fluorescence protocol to stain microRNAs together with protein markers in the PECCs.

Mucosal microRNAs relate to age and severity of disease in ulcerative colitis

Despite significant evidence that the expression of several microRNAs (miRNAs) impacts disease activity in patients with ulcerative colitis (UC), it remains unknown if the more severe disease phenotype seen in pediatric onset UC can be explained by an altered miRNA expression. In this study, we assessed the relationship between miRNA expression, age, and disease severity in pediatric and adult patients with UC. Using RT-qPCR, we analyzed the expression of miR-21, miR-31, miR-126, miR-142 and miR-155 in paraffin embedded rectum biopsies from 30 pediatric and 30 adult-onset UC patients. We found that lesions from adult patients had significantly higher expression levels of miR-21 compared to pediatric patients and that the expression levels of miR-31 (all patients) and miR-155 (pediatric patients only) correlated inversely with histological assessed disease severity. Using in situ hybridization followed by image analysis, the expression level estimates of miR-21 and miR-126 correlated with histological assessed disease severity. In conclusion, we found that the expression of miRNAs depends on the age of the patient and/or the severity of the disease, suggesting that miRNAs may contribute to the regulation of inflammation in UC and could be useful biomarkers in the surveillance of disease severity.

Stem cells as therapeutic targets in colorectal cancer

Colorectal cancer continues to represent a significant burden on public health as the second highest cause of cancer mortality, when men and women are combined, in the US. About 50% of patients either present with late-stage metastatic disease, or develop metastatic recurrences, and ultimately die. In turn, this mortality largely reflects cancer stem cells, tumor-initiating cells that are responsible for cancer progression, drug resistance, recurrence and metastasis. This review summarizes the unique properties of colorectal cancer stem cells, and the emerging strategies by which they can be selectively targeted as a therapeutic approach to eradicating this disease.

Prognostic Value of MicroRNAs in Stage II Colorectal Cancer Patients: A Systematic Review and Meta-Analysis

BACKGROUND

We performed a systematic review and meta-analysis to identify and underline multiple microRNAs (miRNAs) as biomarkers of disease prognosis in stage II colorectal cancer (CRC) patients.

METHODS AND ANALYSIS

This systematic review and meta-analysis study was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The required articles were collected from online bibliographic databases from January 2011 to November 2019 with multiple permutation keywords. Quantitative data synthesis was based on a meta-analysis with pooled data to observe and analyse the outcome measures and effect estimates by using the random effect model. The subgroup analysis was performed from demographic characteristics and the available data.

RESULTS

Eighteen articles were included in this study, 16 of which were incorporated for meta-analysis to examine the stage II CRC prognosis with up- and downregulated miRNA expressions. The pooled hazard ratio (HR) for death in stage II CRC patients was 1.90 (95% confidence interval 1.63-2.211), with a significant p value. A subgroup analysis based on up- or downregulated miRNA expression individually and any deregulated miRNA was also associated with a worse prognosis. The subgroup analysis included parameters such as age, gender, stage II and III combined patients' survival and the repetitive miRNAs (miR21, miR215, miR143-5p, miR106a and miR145) individually.

CONCLUSION

MicroRNAs play a significant role in determining prognosis in stage II CRC patients, with upregulation of miR21, miR215, miR143-5p and miR106a, in particular, portending a worse prognosis. These miRNAs could be considered for further evaluation as biomarkers of prognosis and to guide the decision to administer adjuvant chemotherapy.

Metabolic Reprogramming of Fibroblasts as Therapeutic Target in Rheumatoid Arthritis and Cancer: Deciphering Key Mechanisms Using Computational Systems Biology Approaches

Fibroblasts, the most abundant cells in the connective tissue, are key modulators of the extracellular matrix (ECM) composition. These spindle-shaped cells are capable of synthesizing various extracellular matrix proteins and collagen. They also provide the structural framework (stroma) for tissues and play a pivotal role in the wound healing process. While they are maintainers of the ECM turnover and regulate several physiological processes, they can also undergo transformations responding to certain stimuli and display aggressive phenotypes that contribute to disease pathophysiology. In this review, we focus on the metabolic pathways of glucose and highlight metabolic reprogramming as a critical event that contributes to the transition of fibroblasts from quiescent to activated and aggressive cells. We also cover the emerging evidence that allows us to draw parallels between fibroblasts in autoimmune disorders and more specifically in rheumatoid arthritis and cancer. We link the metabolic changes of fibroblasts to the toxic environment created by the disease condition and discuss how targeting of metabolic reprogramming could be employed in the treatment of such diseases. Lastly, we discuss Systems Biology approaches, and more specifically, computational modeling, as a means to elucidate pathogenetic mechanisms and accelerate the identification of novel therapeutic targets.

An alternative miRISC targets a cancer-associated coding sequence mutation in FOXL2

Recent evidence suggests that animal microRNAs (miRNAs) can target coding sequences (CDSs); however, the pathophysiological importance of such targeting remains unknown. Here, we show that a somatic heterozygous missense mutation (c.402C>G; p.C134W) in FOXL2, a feature shared by virtually all adult-type granulosa cell tumors (AGCTs), introduces a target site for miR-1236, which causes haploinsufficiency of the tumor-suppressor FOXL2. This miR-1236-mediated selective degradation of the variant FOXL2 mRNA is preferentially conducted by a distinct miRNA-loaded RNA-induced silencing complex (miRISC) directed by the Argonaute3 (AGO3) and DHX9 proteins. In both patients and a mouse model of AGCT, abundance of the inversely regulated variant FOXL2 with miR-1236 levels is highly correlated with malignant features of AGCT. Our study provides a molecular basis for understanding the conserved FOXL2 CDS mutation-mediated etiology of AGCT, revealing the existence of a previously unidentified mechanism of miRNA-targeting disease-associated mutations in the CDS by forming a non-canonical miRISC.

miR-588 is a prognostic marker in gastric cancer

In an effort to identify a novel microRNA (miRNA) as a gastric cancer (GC) treatment target and prognostic biomarker, we surveyed The Cancer Genome Atlas database and found that miR-588 expression is low in GC tissues. This was confirmed by real-time reverse transcription polymerase chain reaction assays of GC patient plasma samples and SGC7901 and MNK28 cells. A constructed miRNA-mRNA network showed that CXCL5, CXCL9, and CXCL10 are target genes of miR-588. Analysis of the miRWalk database revealed that miR-588 directly binds to CXCL5 and CXCL9. Overexpression of miR-588 reduced GC cell proliferation in vitro and in vivo. High expression of miR-588 inhibited Ki-67 expression in vivo. The FunRich database also showed that CXCL5, CXCL9, and CXCL10 are involved in immune responses, while the Database of Immune Cell Expression showed they are differentially expressed in CD8+ T cells. High expression of CXCL9 and CXCL10 correlated positively with infiltrating levels of CD4+ T and CD8+ T cells in stomach adenocarcinoma. High expression of miR-588, CXCL5, CXCL9, and CXCL10 was associated with prolonged survival of GC patients. These findings indicate that miR-588 is a biomarker for tumor-associated immune infiltration and a prognostic marker in GC patients.

An alternative miRISC targets a cancer-associated coding sequence mutation in FOXL2

Recent evidence suggests that animal microRNAs (miRNAs) can target coding sequences (CDSs); however, the pathophysiological importance of such targeting remains unknown. Here, we show that a somatic heterozygous missense mutation (c.402C>G; p.C134W) in FOXL2, a feature shared by virtually all adult-type granulosa cell tumors (AGCTs), introduces a target site for miR-1236, which causes haploinsufficiency of the tumor-suppressor FOXL2. This miR-1236-mediated selective degradation of the variant FOXL2 mRNA is preferentially conducted by a distinct miRNA-loaded RNA-induced silencing complex (miRISC) directed by the Argonaute3 (AGO3) and DHX9 proteins. In both patients and a mouse model of AGCT, abundance of the inversely regulated variant FOXL2 with miR-1236 levels is highly correlated with malignant features of AGCT. Our study provides a molecular basis for understanding the conserved FOXL2 CDS mutation-mediated etiology of AGCT, revealing the existence of a previously unidentified mechanism of miRNA-targeting disease-associated mutations in the CDS by forming a non-canonical miRISC.

Potential of miR-21 to Predict Incomplete Response to Chemoradiotherapy in Rectal Adenocarcinoma

Background: Patients with locally advanced rectal adenocarcinoma (LARC) are treated with neoadjuvant chemoradiotherapy (CRT). However, biomarkers for patient selection are lacking, and the association between miRNA expression and treatment response and oncological outcomes is unclear.

Objectives: To investigate miRNAs as predictors of response to neoadjuvant CRT and its association with oncological outcomes.

Methods: This retrospective study analyzed miRNA expression (miR-16, miR-21, miR-135b, miR-145, and miR-335) in pre- and post-chemoradiation rectal adenocarcinoma tissue and non-neoplastic mucosa in 91 patients treated with neoadjuvant CRT (50.4 Gy) and proctectomy. Two groups were defined: a pathological complete responders group (tumor regression grade—TRG 0) and a pathological incomplete responders group (TRG 1, 2, and 3).

Results: miR-21 and miR-135b were upregulated in tumor tissue of incomplete responders comparing with non-neoplastic tissue (p = 0.008 and p < 0.0001, respectively). Multivariate analysis showed significant association between miR-21 in pre-CRT tumor tissue and response, with a 3.67 odds ratio (OR) of incomplete response in patients with higher miR-21 levels (p = 0.04). Although with no significance, patients treated with 5-fluorouracil (5-FU) presented reduced odds of incomplete response compared with those treated with capecitabine (OR = 0.19; 95% confidence interval (CI) 0.03–1.12, p = 0.05). Moreover, significant differences were seen in overall survival (OS) in relation to clinical TNM stage (p = 0.0004), cT (p = 0.0001), presence of distant disease (p = 0.002), mesorectal tumor deposits (p = 0.003), and tumor regression grade (p = 0.04).

Conclusion: miR-21 may predict response to CRT in rectal cancer (RC).

MicroRNA Biomarkers in IBD-Differential Diagnosis and Prediction of Colitis-Associated Cancer

Inflammatory bowel disease (IBD) includes Crohn's disease (CD) and ulcerative colitis (UC). These are chronic autoimmune diseases of unknown etiology affecting the gastrointestinal tract. The IBD population includes a heterogeneous group of patients with varying disease courses requiring personalized treatment protocols. The complexity of the disease often delays the diagnosis and the initiation of appropriate treatments. In a subset of patients, IBD leads to colitis-associated cancer (CAC). MicroRNAs are single-stranded regulatory noncoding RNAs of 18 to 22 nucleotides with putative roles in the pathogenesis of IBD and colorectal cancer. They have been explored as biomarkers and therapeutic targets. Both tissue-derived and circulating microRNAs have emerged as promising biomarkers in the differential diagnosis and in the prognosis of disease severity of IBD as well as predictive biomarkers in drug resistance. In addition, knowledge of the cellular localization of differentially expressed microRNAs is a prerequisite for deciphering the biological role of these important epigenetic regulators and the cellular localization may even contribute to an alternative repertoire of biomarkers. In this review, we discuss findings based on RT-qPCR, microarray profiling, next generation sequencing and in situ hybridization of microRNA biomarkers identified in the circulation and in tissue biopsies.

Evaluation of Tissue and Circulating miR-21 as Potential Biomarker of Response to Chemoradiotherapy in Rectal Cancer

Response to chemoradiotherapy (CRT) in patients with locally advanced rectal cancer (RC) is quite variable and it is urgent to find predictive biomarkers of response. We investigated miR-21 as tissue and plasma biomarker of response to CRT in a prospective cohort of RC patients; The expression of miR-21 was analyzed in pre- and post-CRT rectal tissue and plasma in 37 patients with RC. Two groups were defined: Pathological responders (TRG 0, 1 and 2) and non-responders (TRG 3). The association between miR-21, clinical and oncological outcomes was assessed; miR-21 was upregulated in tumor tissue and we found increased odds of overexpression in pre-CRT tumor tissue (OR: 1.63; 95% CI: 0.40-6.63, p = 0.498) and pre-CRT plasma (OR: 1.79; 95% CI: 0.45-7.19, p = 0.414) of non-responders. The overall recurrence risk increased with miR-21 overexpression in pre-CRT tumor tissue (HR: 2.175, p = 0.37); Significantly higher miR-21 expression is observed in tumor tissue comparing with non-neoplastic. Increased odds of non-response is reported in patients expressing higher miR-21, although without statistical significance. This is one of the first studies on circulating miR-21 as a potential biomarker of response to CRT in RC patients.

Myeloid-Derived Suppressor Cells in Colorectal Cancer

Colorectal cancer (CRC) remains one of the most common malignancies diagnosed worldwide. The pathogenesis of CRC is complex and involves, among others, accumulation of genetic predispositions and epigenetic factors, dietary habits, alterations in gut microbiota, and lack of physical activity. A growing body of evidence suggests that immune cells play different roles in CRC, comprising both pro- and anti-tumorigenic functions. Immunosuppression observed during cancer development and progression is a result of the orchestration of many cell types, including myeloid-derived suppressor cells (MDSCs). MDSCs, along with other cells, stimulate tumor growth, angiogenesis, and formation of metastases. This article focuses on MDSCs in relation to their role in the initiation and progression of CRC. Possible forms of immunotherapies targeting MDSCs in CRC are also discussed.

Tumor Tissue MIR92a and Plasma MIRs21 and 29a as Predictive Biomarkers Associated with Clinicopathological Features and Surgical Resection in a Prospective Study on Colorectal Cancer Patients

Cancer-related microRNAs (miRNAs) are emerging as non-invasive biomarkers for colorectal cancer (CRC). This study aimed to analyze the correlation between the levels of tissue and plasma miRNAs and clinicopathological characteristics and surgical resection. This study was a prospective study of CRC patients who underwent surgery. Forty-four sample pairs of tissue and plasma were analyzed. The miRNA levels were evaluated by RT-qPCR. The level of tumor tissue MIR92a showed a significant difference in CRC with lymph node metastasis, stage ≥ III, and high lymphatic invasion. In preoperative plasma, there were significant differences in CRC with stage ≥ III (MIR29a) and perineural invasion (MIR21). In multivariate analysis of lymphatic invasion, the levels of both preoperative plasma MIR29a and tumor tissue MIR92a showed significant differences. Furthermore, in cases with higher plasma miRNA level, the levels of plasma MIRs21 and 29a were significantly decreased after the operation. In this study, there were significant differences in miRNAs levels with respect to the sample type, clinicopathological features, and surgical resection. The levels of tumor tissue MIR92a and preoperative plasma MIR29a may have the potential as a biomarker for prognosis. The plasma MIRs21 and 29a level has the potential to be a predictive biomarker for treatment efficacy.

MicroRNA-132 regulates salt-dependent steady-state renin levels in mice

The body's salt and fluid balance is regulated by the renin-angiotensin-aldosterone system. Generation of prostaglandin-E2 (PGE2) in a cyclo-oxygenase-2 (COX-2)-dependent manner in the macula densa, the salt-sensing cells of the kidney, plays a dominant role in renin regulation. Here we show that miR-132 directly targets Cox-2 and affects subsequent PGE2 and renin levels. MiR-132 is induced and reduced by low- and high salt treatment, respectively, in a p38- and ERK1/2-independent and CREB- and salt inducible kinase-dependent manner. Silencing of miR-132 in mice increases macula densa COX-2 expression and elevates PGE2 and renin levels, which are abrogated by the selective COX-2-inhibitor Celecoxib. Furthermore, a low or high salt diet induces and reduces macula densa miR-132 expression, while low salt diet combined with silencing miR-132 further increases renin levels. Taken together, we demonstrate a posttranscriptional regulatory role for salt-dependent miR-132 in fine-tuning the steady-state levels of renin.

Associations Between miRNAs and Two Different Cancers: Breast and Colon

Objective

Screening approaches using microRNAs (miRNAs) have been gaining increased attention owing to their potential applications in the diagnosis, prognosis, and monitoring of cancer, because aberrant miRNA expression plays a role in the development and advancement of malignancies. The objectives of this study were to characterize mir21, miR31, mir143, mir145, and control RNU43, which are differentially expressed in peripheral blood mononuclear cells (PBMCs) of breast and colorectal cancer patients, compared to that in controls and to establish whether this is specific to breast and colon cancer for use as tumor markers.

Methods

Thirty newly diagnosed patients with breast cancer and 30 patients with colorectal cancer were enrolled together with 30 healthy controls. PBMCs were isolated from venous blood samples of individuals. Next, miRNA expression analysis was performed by a two-step method of reverse transcription and qPCR.

Results

The expression levels of miR-143 and miR-31 were significantly decreased, whereas the expression levels of miR-145 and miR-21 were significantly increased in breast cancer patients compared to those in healthy subjects. Moreover, the expression levels of miR-143, miR-145, and miR-21 were significantly increased and, in contrast, the changes in the expression levels of miR-31 were not statistically significant in colon cancer compared to those in healthy subjects. miR-21 exhibited the highest increase in both breast and colon cancers. There was a weak positive correlation between miR-145 and CA-15.3 in patients with breast cancer (r = 0.451; p = 0.012). miR-143 was positively correlated with the TNM stage in colon cancer patients (r = 0.568; p = 0.001).

Conclusion

A biomarker panel composed of miR-21, miR-31, miR-143, and miR-145 in PBMC may provide a new diagnostic approach for the early detection of breast and colon cancer. As miR-21 expression was found to be the highest among all the miRNAs evaluated, it may represent a new tumor biomarker and a candidate therapeutic drug or gene target in colon and breast cancer.

Identifying a new microRNA signature as a prognostic biomarker in colon cancer

BACKGROUND

The aim was to identify a novel prognostic miRNA signature for colon cancer (CC) in silico.

METHODS

Data on the expression of miRNAs and relevant clinical information for 407 patients were obtained from The Cancer Genome Atlas (TCGA), and the samples were randomly split into a validation set (n = 203) and training set (n = 204). The differential expression of miRNAs between normal tissues and patients with CC was analyzed. We detected a miRNA expression signature in the training dataset by using a Cox proportional hazard regression model. Then, we verified the signature in the validation set. Association of the miRNA signature with overall survival was assessed in the validation cohort and combined cohort by log-rank test and based on Kaplan-Meier curves. The receiver operating characteristic and disease-free survival analyses were performed to evaluate the miRNA signature of CC in the combined cohort. Multivariate and univariate Cox analyses related to survival for the miRNA signature were performed, and a nomogram was built as a prognostic model for CC. To explore the function of target genes of the miRNA signature, Gene Ontology analysis and Kyoto Encyclopedia of Genes and Genomes pathway analysis were used.

RESULTS

Between the matched normal tissues and colon cancer tissues, 267 differentially expressed miRNAs were detected, and a single-factor CoxPH model showed that 13 miRNAs were related to overall survival in the training cohort. Then, a five-miRNA signature was identified using a CoxPH regression model with multiple factors. The five-miRNA signature had significant prognostic value in the training cohort and was validated in the validation cohort and combined cohort. A total of 193 target genes of the miRNA signature were identified. According to the results of functional analysis of the target genes, the signaling pathways MAPK, AMPK and PI3K-Akt, focal adhesion, and microRNAs in cancer were remarkably enriched.

CONCLUSION

A five-miRNA signature had increased prognostic value for CC, which may provide important biological insights for the discovery and development of molecular predictors to improve the prognosis of patients with CC.

MicroRNAs expression profiling in Egyptian colorectal cancer patients

Egypt has increased incidence and high rate of early onset colorectal cancer (CRC). This study aimed to profile the expression levels of 84 circulating microRNAs (miRNAs) in Egyptian CRC patients and to evaluate the diagnostic accuracy of some selected miRNAs as diagnostic biomarkers for CRC patients. A total of 129 subjects (84 CRC patients and 45 healthy controls) were enrolled in two independent sample sets: the screening set (39 subjects) and the validation set (90 subjects). The expression profiles of 84 miRNAs were studied by miRNA PCR array in the screening set. Then four miRNAs (let-7c, 21, 26a, 146a) were selected to be studied by quantitative real-time PCR in the validation set. The PCR array results revealed significant up regulation of 20 miRNAs and downregulation of two miRNAs in CRC patients compared to the healthy subjects. Moreover, the expression levels of the four selected miRNAs were significantly higher in CRC serum samples than controls. The ROC analysis revealed that miRNAs (let-7c, 21, 26a and 146a) can effectively discriminate between CRC patients and the controls. The combination of the four miRNAs showed AUC of 0.950 (95% CI [0.898-1.002], p = .001). However, the combination of miR-21 and miR-26a showed the best diagnostic accuracy with AUC of 0.953 (95% CI [0.908-0.999], p = .001). The current data suggest that miRNAs (let-7c, 21, 26a, 146a) could play an important role in CRC development and they can be used as diagnostic biomarkers for CRC.

Spatial and phenotypic characterization of pancreatic cancer-associated fibroblasts after neoadjuvant treatment

Pancreatic ductal adenocarcinoma (PC) is characterized by a highly fibrotic desmoplastic stroma. Subtypes of cancer-associated fibroblasts (CAFs) have been identified in chemotherapy-naïve PC (CTN-PC), but their precise functions are still unclear. Our knowledge regarding the properties of CAFs in the regressive stroma after neoadjuvant treatment (NAT) of PC (NAT-PC) is particularly limited. We aimed to examine the marker phenotypic properties of CAFs in the regressive stroma of PC. Surgical specimens from patients with CTN-PC (n=10) and NAT-PC (n=10) were included. Juxtatumoural, peripheral, lobular, septal, peripancreatic, and regressive stromal compartments were manually outlined using digital imaging analysis (DIA) for area quantification. The compartment-specific expression of CD271, cytoglobin, DOG-1, miR-21, osteonectin, PDGF-Rβ, and tenascin C was evaluated by immunohistochemistry or in situ hybridization, using manual scoring and automated DIA. The area fraction of the regressive stroma was significantly higher in NAT-PC than in CTN-PC (P=0.0002). CD271 (P<0.01), cytoglobin (P<0.05), DOG1 (P<0.05), miR-21 (P<0.05), and tenascin C (P<0.05) exhibited significant differences in their expression profiles between the juxtatumoural compared to the peripheral and regressive stroma. PDGF-Rβ expression was significantly higher in juxtatumoural than in peripheral CAFs (P<0.05). Our data provide further support of the concept of stromal heterogeneity and phenotypic different CAF subtypes in PC. CAFs in the regressive stroma of NAT-PC show a marker phenotype similar to some (namely, peripheral) and different from other (namely, juxtatumoural) previously defined CAF subtypes. It may be hypothesized that phenotypic CAF subtypes, at least in part, also may share functional properties. Studies examining the precise functional characteristics of CAF subtypes in PC are needed.

miRNAs derived from cancer-associated fibroblasts in colorectal cancer

Currently, the incidence of colorectal cancer (CRC) is increasing across the world. The cancer stroma exerts an impact on the spread, invasion and chemoresistance of CRC. The tumor microenvironment involves a complex interaction between cancer cells and stromal cells, for example, cancer-associated fibroblasts (CAFs). CAFs can promote neoplastic angiogenesis and tumor development in CRC. Mounting evidence suggests that many miRNAs are overexpressed (miR-21, miR-329, miR-181a, miR-199a, miR-382 and miR-215) in CRC CAFs, and these miRNAs can influence the spread, invasiveness and chemoresistance in neighboring tumor cells via paracrine signaling. Herein, we summarize the pathogenic roles of miRNAs and CAFs in CRC. Moreover, for first time, we highlight the miRNAs derived from CRC-associated CAFs and their roles in CRC pathogenesis.

Co-staining of microRNAs and their target proteins by miRNA in situ hybridization and immunohistofluorescence on prostate cancer tissue microarrays

The co-expression of miRNAs and their target proteins was studied on tissue microarrays from different prostate cancer (PCa) patients. PCa of primary Gleason pattern 4 (GP4), lymph node metastases of GP4, distant metastases, and normal tissue from the transitional and peripheral zones were co-stained by fluorescent miRNA in situ hybridization (miRisH) and protein immunohistofluorescence (IHF). The miRNAs and corresponding target proteins include the pairs miR-145/ERG, miR-143/uPAR, and miR-375/SEC23A. The fluorescence-stained and scanned tissue microarrays (TMAs) were evaluated by experienced uropathologists. The pair miR-145/ERG showed an exclusive staining for miR-145 in the nuclei of stromal cells, both in tumor and normal tissue, and for ERG in the cytoplasm with/without co-expression in the nucleus of tumor cells. The pair miR-143/uPAR revealed a clear distinction between miR-143 in the nuclei of stromal cells and uPAR staining in the cytoplasm of tumor cells. Metastases (lymph node and distant) however, showed tumor cells with cytoplasmic staining for miR-143/uPAR. In normal tissues, beside the nuclei of the stroma cells, gland cells could also express miR-143 and uPAR in the cytoplasm. miR-375 showed particular staining in the nucleoli of GP4 and metastatic samples, suggesting that nucleoli play a special role in sequestering proteins and miRNAs. Combined miRisH/IHF allows for the study of miRNA expression patterns and their target proteins at the single-cell level.

Silencing of miR-182 is associated with modulation of tumorigenesis through apoptosis induction in an experimental model of colorectal cancer

BACKGROUND

miR-182-5p (miR-182) is an oncogenic microRNA (miRNA) found in different tumor types and one of the most up-regulated miRNA in colorectal cancer (CRC). Although this microRNA is expressed in the early steps of tumor development, its role in driving tumorigenesis is unclear.

METHODS

The effects of miR-182 silencing on transcriptomic profile were investigated using two CRC cell lines characterized by different in vivo biological behavior, the MICOL-14h-tert cell line (dormant upon transfer into immunodeficient hosts) and its tumorigenic variant, MICOL-14tum. Apoptosis was studied by annexin/PI staining and cleaved Caspase-3/PARP analysis. The effect of miR-182 silencing on the tumorigenic potential was addressed in a xenogeneic model of MICOL-14tum transplant.

RESULTS

Endogenous miR-182 expression was higher in MICOL-14tum than in MICOL-14h-tert cells. Interestingly, miR-182 silencing had a strong impact on gene expression profile, and the positive regulation of apoptotic process was one of the most affected pathways. Accordingly, annexin/PI staining and caspase-3/PARP activation demonstrated that miR-182 treatment significantly increased apoptosis, with a prominent effect in MICOL-14tum cells. Moreover, a significant modulation of the cell cycle profile was exerted by anti-miR-182 treatment only in MICOL-14tum cells, where a significant increase in the fraction of cells in G0/G1 phases was observed. Accordingly, a significant growth reduction and a less aggressive histological aspect were observed in tumor masses generated by in vivo transfer of anti-miR-182-treated MICOL-14tum cells into immunodeficient hosts.

CONCLUSIONS

Altogether, these data indicate that increased miR-182 expression may promote cell proliferation, suppress the apoptotic pathway and ultimately confer aggressive traits on CRC cells.

Combined MicroRNA In Situ Hybridization and Immunohistochemical Detection of Protein Markers

MicroRNAs are short (18-23 nucleotides) noncoding RNAs involved in posttranscriptional regulation of gene expression through their specific binding to the 3'UTR of mRNAs. MicroRNAs can be detected in tissues using specific locked nucleic acid (LNA)-enhanced probes. The characterization of microRNA expression in tissues by in situ detection is often crucial following a microRNA biomarker discovery phase in order to validate the candidate microRNA biomarker and allow better interpretation of its molecular functions and derived cellular interactions. The in situ hybridization data provides information about contextual distribution and cellular origin of the microRNA. By combining microRNA in situ hybridization with immunohistochemical staining of protein markers, it is possible to precisely characterize the microRNA-expressing cells and to identify the potential microRNA targets. This combined technology can also help to monitor changes in the level of potential microRNA targets in a therapeutic setting. In this chapter, we present a fluorescence-based detection method that allows the combination of microRNA in situ hybridization with immunohistochemical staining of one and, in this updated version of the paper, two protein markers detected with primary antibodies raised in the same host species.

miR-21: a promising biomarker for the early detection of colon cancer

Purpose

The aim of this study was to compare the expression of miR-21 gene in stages II-IV of formalin-fixed paraffin-embedded (FFPE) tissue in patients with colon cancer and introduce miR-21 as a potential molecular marker for detection of colon cancer in the early stages.

Introduction

Currently, identification of key molecules involved in the pathogenesis of cancer is one of the areas under consideration. miRNAs, are small RNAs which have been identified in many cancers. In this study, we investigated the expression of miR-21 in three pathologic stages in patients with colon cancer in the north of Iran.

Patients and methods

A total of 40 FFPE samples were obtained from patients with stages II, III, and IV from hospitals in Mazandaran and Golestan provinces. After extraction of RNA, treatment with DNase I and cDNA synthesis was performed and miR-21 expression was assessed by qPCR. Then, the data were analyzed using statistical software R (3.4.3).

Results

The expression of miR-21 in stage II was significantly different from stage IV. However, no significant difference was observed between the other stages. In stage II, the level of miR-21 expression was higher in men than women. Moreover, in the second pathological stage, miR-21 expression was reduced in patients with adjacent lymphoid tissue engagement. In addition, the expression of miR-21 in grade I was significantly higher than grade II.

Conclusion

The results of this study suggest that miR-21 can be a diagnostic marker for early stages of colon cancer, especially in men. It can also be considered as a good candidate for targeted treatment of colon cancer in the early stages of the disease. Furthermore, for the first time, we suggested that miR-21 can be a good molecular marker for classification of the stages of colon cancer.

MicroRNA in Acupuncture Studies: Does Small RNA Shed Light on the Biological Mechanism of Acupuncture?

MicroRNAs (miRNAs) are the main regulators of diverse physiological processes. Recently, miRNAs have emerged as significant players related to the effect of acupuncture although the biological mechanisms connecting the function of these miRNAs with the effect of acupuncture are not well understood. In animal models of various diseases, such as neurological disease, cardiovascular disease, myopathy, and pain, a number of miRNAs were altered after administration of electroacupuncture or manual acupuncture. Nonetheless, there are a limited number of studies published so far. This paper reviewed and discussed whether miRNAs could elucidate potential biological mechanism of acupuncture in the future studies.

Evaluation of bisphenol A exposure induced oxidative RNA damage by liquid chromatography-mass spectrometry

Highlighted evidence suggests the possible implication of bisphenol A (BPA) exposure on a variety of biological functions, such as DNA damage. Similar to DNA, exposed to BPA may also have potential risks to RNA damage due to its induction of reactive oxygen species. However, there are no related research reports about such health risks of BPA. Therefore, this work tried to investigate the BPA exposure induced oxidative RNA damage by detecting urinary nucleosides, the end-products of RNA metabolism. An ultra-high performance liquid chromatography-Orbitrap mass spectrometry method was applied to selectively and sensitively determine urinary nucleosides. As a result, 66 nucleosides were identified and the effects of BPA exposure on these nucleosides in rat urine samples were evaluated. The nucleosides showed different changing tendency along with different exposure dose of BPA. The strongest effect was observed in high does-exposure rats, indicating dose-response relationship between BPA-treatment and urinary nucleosides. Significant change of some nucleosides, including 8-oxoguanosine, was observed in the high-dose exposure group, suggesting obvious RNA damage to rats. To the best of our knowledge, it is the first study about the RNA damage induced by BPA exposure. The results provided a new perspective on the toxic effects of BPA exposure.

Co-Detection of miR-21 and TNF-α mRNA in Budding Cancer Cells in Colorectal Cancer

MicroRNA-21 (miR-21) is upregulated in many cancers including colon cancers and is a prognostic indicator of recurrence and poor prognosis. In colon cancers, miR-21 is highly expressed in stromal fibroblastic cells and more weakly in a subset of cancer cells, particularly budding cancer cells. Exploration of the expression of inflammatory markers in colon cancers revealed tumor necrosis factor alpha (TNF-α) mRNA expression at the invasive front of colon cancers. Surprisingly, a majority of the TNF-α mRNA expressing cells were found to be cancer cells and not inflammatory cells. Because miR-21 is positively involved in cell survival and TNF-α promotes necrosis, we found it interesting to analyze the presence of miR-21 in areas of TNF-α mRNA expression at the invasive front of colon cancers. For this purpose, we developed an automated procedure for the co-staining of miR-21, TNF-α mRNA and the cancer cell marker cytokeratin based on analysis of frozen colon cancer tissue samples (n = 4) with evident cancer cell budding. In all four cases, TNF-α mRNA was seen in a small subset of cancer cells at the invasive front. Evaluation of miR-21 and TNF-α mRNA expression was performed on digital slides obtained by confocal slide scanning microscopy. Both co-expression and lack of co-expression with miR-21 in the budding cancer cells was noted, suggesting non-correlated expression. miR-21 was more often seen in cancer cells than TNF-α mRNA. In conclusion, we report that miR-21 is not linked to expression of the pro-inflammatory cytokine TNF-α mRNA, but that miR-21 and TNF-α both take part in the cancer expansion at the invasive front of colon cancers. We hypothesize that miR-21 may protect both fibroblasts and cancer cells from cell death directed by TNF-α paracrine and autocrine activity.

Altered miR-21, miRNA-148a Expression in Relation to KRAS Mutation Status as Indicator of Adenoma-Carcinoma Transitional Pattern in Colorectal Adenoma and Carcinoma Lesions

Sporadic colorectal cancer (CRC) is a fatal disease, mostly known as the silent killer, due to the fact that this disease is asymptomatic before diagnosis in advanced stage. Screening and the early detection of CRC and colorectal adenoma (CRA) by non-aggressive molecular biomarkers' signature is useful for improvement of survival rate in CRC patients. To achieve such a goal, a better understanding of distinct molecular abnormalities as candidate biomarkers in CRC development is crucial. In this study, seventy-five archived FFPE CRC samples, including colorectal adenocarcinoma, adenomatous polyps (adenoma), and adjacent non-neoplastic mucosa were collected for the investigation by Sanger sequencing at the DNA level and by real-time PCR at the RNA level. The results of the KRAS mutational analysis have shown that the majority of somatic mutations in the KRAS affect only one codon, mainly codon 12(p.G12D) with low frequency in adenomas (13.3%) versus CRCs (36%). The results of dysregulated epigenetic changes of miR-21 clearly showed upregulation of expression in colorectal adenocarcinoma, compared to non-neoplastic mucosa, in colorectal adenoma vs non-neoplastic mucosa: (p < 0.001) and in CRC versus adenoma (p < 0.001); while miR-148a expression were significantly downregulated in CRC, compared to non-neoplastic mucosa, in colorectal adenoma vs non-neoplastic mucosa, and in adenoma vs CRC (p < 0.001). Our findings support the important role of miR-21 in stages I-II of CRC, and the KRAS G12D mutant, and differential miR-148a expression, in advanced stages of CRC.

Host⁻MicroRNA⁻Microbiota Interactions in Colorectal Cancer

Changes in gut microbiota composition have consistently been observed in patients with colorectal cancer (CRC). Yet, it is not entirely clear how the gut microbiota interacts with tumor cells. We know that tumor cells undergo a drastic change in energy metabolism, mediated by microRNAs (miRNAs), and that tumor-derived miRNAs affect the stromal and immune cell fractions of the tumor microenvironment. Recent studies suggest that host intestinal miRNAs can also affect the growth and composition of the gut microbiota. Our previous CRC studies showed a high-level of interconnectedness between host miRNAs and their microbiota. Considering all the evidence to date, we postulate that the altered nutrient composition and miRNA expression in the CRC microenvironment selectively exerts pressure on the surrounding microbiota, leading to alterations in its composition. In this review article, we present our current understanding of the role of miRNAs in mediating host–microbiota interactions in CRC.

SAV1, regulated by microRNA-21, suppresses tumor growth in colorectal cancer

This study investigated the role and action of the Salvador 1 protein (SAV1, also called WW45) in colorectal cancer (CRC). For this, CRC SW480 and HCT116 cells were infected with lentiviruses of SAV1 overexpression vector (lenti-SAV1) and SAV1 short hairpin RNA (sh-SAV1) to overexpress and silence SAV1 respectively, or transfected with microRNA-21 (miR-21) mimic to overexpress miR-21. Relative mRNA levels of SAV1 and relative miR-21 levels in CRC tissues or cells were detected. The effects of SAV1 and miR-21 on cell proliferation and apoptosis were evaluated using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and annexin V – fluorescein isothiocyanate (FITC) – propidium iodide (PI) flow cytometry, respectively. Our results revealed that SAV1 was downregulated in CRC tissues compared with the adjacent noncancerous tissues. Furthermore, SAV1 overexpression inhibited proliferation and promoted apoptosis in SW480 and HCT116 cells, whereas knockdown of SAV1 exerted the opposite effect. Additionally, the tumorigenesis of SW480 cells in xenografted mice was significantly inhibited by SAV1 overexpression but promoted by SAV1 knockdown. MiR-21 levels significantly and negatively correlated with SAV1 expression in CRC tissues. More importantly, miR-21 overexpression significantly abolished the SAV1-mediated inhibition of proliferation and stimulation of apoptosis of SW480. In conclusion, SAV1 suppresses tumor growth in CRC and is regulated by miR-21.

Validation of miRNA prognostic significance in stage II colorectal cancer: A protocol for systematic review and meta-analysis of observational clinical studies

BACKGROUND

Advances in early detection and treatment of colorectal cancer (CRC) has seen marked improvements in recent years. However, it is still the third leading cause of cancer-related deaths worldwide. Although there are studies reporting the significance of miRNAs in stage II colorectal cancer, there is no known comprehensive study utilising collective data from multiple published studies. Thus, this study will focus on performing a systematic review and meta-analysis using published data to identify and underline multiple miRNA targets, with regard to disease prognosis in stage II CRC patients.

METHODS

The systematic review will be reported according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, 2015 statement. The required articles will be obtained via a search of bibliographical databases such as Cochrane Library, EMBASE, MEDLINE, PubMed, and Web of Science. A set of keywords in multiple permutations will be used for the search. The reference lists of included studies will also be manually searched to further increase the robustness of the search results. The systematic review will primarily be done via a literary synthesis.

RESULTS

Quantitative data synthesis will be based on estimated effect across the studies with forest plots generated to observe pooled outcome measures. A fixed or random-effect model of meta-analysis will be used depending upon the heterogeneity observed between studies. Subgroup analysis will be carried out depending on the availability of sufficient clinical data.

CONCLUSION

Based on the systematic review and meta-analysis results of this study, the possible miRNAs could be predicted toward the prognosis of stage II colorectal cancer, and specific miRNAs may perhaps be considered as a biomarker and therapeutic target for this malignancy.

Circulating inflammation signature predicts overall survival and relapse-free survival in metastatic colorectal cancer

BACKGROUND

Metastatic colorectal cancer (mCRC) is a highly heterogeneous disease from a clinical, molecular, and immunological perspective. Current predictive models rely primarily in tissue based genetic analysis, which not always correlate with inflammatory response. Here we evaluated the role of a circulating inflammatory signature as a prognostic marker in mCRC.

METHODS

Two hundred eleven newly diagnosed patients with mCRC were enrolled in the study. One hundred twenty-one patients had unresectable metastases, whereas ninety patients had potentially resectable liver metastases at presentation. Analysis of miR-21, IL-6, and IL-8 in the plasma of peripheral blood was performed at baseline. Patients with high circulating levels of ≥2 of the three inflammation markers (miR-21, IL-6, and IL-8) were considered to have the "Inflammation phenotype-positive CISIG".

RESULTS

Positive CISIG was found in 39/90 (43%) and 50/121 (45%) patients in the resectable and unresectable cohort, respectively. In the resectable population the median relapse-free survival was 18.4 compared to 31.4 months (p = 0.001 HR 2.09, 95% CI 1.2-3.67) for positive vs. negative CISIG. In contrast, the individual components were not significant. In the same population the median overall survival was 46.2 compared to 66.0 months (p = 0.0003, HR 2.57, 95% CI 1.26-5.27) for positive vs. negative CISIG, but not significant for the individual components. In the unresectable population, the median overall survival was 13.5 compared to 25.0 months (p = 0.0008, HR 2.49, 95% CI 1.46-4.22) for positive vs. negative CISIG. IL-6 was independently prognostic with overall survival of 16.2 compared to 27.0 months (p = 0.004, HR 1.96, 95% CI 1.24-3.11) for high vs. low IL-6, but not the other components. Using a Cox regression model, we demonstrated that CISIG is an independent predictive marker of survival in patients with unresectable disease (HR 1.8, 95% CI 1.2, 2.8, p < 0.01).

CONCLUSION

In two different cohorts, we demonstrated that CISIG is a strong prognostic factor of relapse-free and overall survival of patients with mCRC. Based on these data, analysis of circulating inflammatory signaling can be complimentary to traditional molecular testing.