Circulating levels of the miRNAs, miR-194, and miR-29b, as clinically useful biomarkers for colorectal cancer

The potential of miR-29 in modulating tumor angiogenesis: a comprehensive review

MicroRNAs (miRNAs) are a class of short non-coding RNAs that play a crucial role in the post-transcriptional regulation of gene expression. They are associated with various biological processes related to tumors. Among the numerous miRNAs, miR-29 has garnered attention for its role in regulating tumor angiogenesis. In numerous human tumors, miR-29 has been demonstrated to negatively correlate with the capacity for angiogenesis and the degree of malignancy, as well as with the expression levels of pro-angiogenic factors such as vascular endothelial growth factor vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and matrix metalloproteinase (MMP)-2. Multiple studies, utilizing techniques like dual-luciferase reporter assays, have confirmed that miR-29 directly targets the 3'-untranslated region (UTR) of mRNAs for VEGF, PDGF, and MMP-2. Extensive investigations involving tumor cell lines and animal models have shown that the overexpression of miR-29, achieved through miRNA transfection or the introduction of miRNA mimics, effectively inhibits angiogenesis by upregulating these pro-angiogenic factors. Conversely, downregulation of miR-29 using specific inhibitors promotes angiogenesis. While small molecule inhibitors and antibodies targeting VEGF constitute a primary strategy in anti-angiogenesis therapies, miR-29's ability to target multiple pro-angiogenic molecules positions it as a promising candidate for future therapeutic interventions, especially with ongoing advancements in nucleic acid drug design and delivery systems.

Advances in microRNAs as Emerging Biomarkers for Colorectal Cancer Early Detection and Diagnosis

Colorectal cancer (CRC) remains the second most common cause of cancer-related mortality worldwide, necessitating advancements in early detection and innovative treatment strategies. MicroRNAs (miRNAs), small non-coding RNAs involved in gene regulation, have emerged as crucial players in the pathogenesis of CRC. This review synthesizes the latest findings on miRNA deregulated in precancerous lesions and in CRC. By examining the deregulation patterns of miRNAs across different stages of CRC development, this review highlights their potential as diagnostic tools. We specifically analyse the roles and diagnostic relevance of four miRNAs-miR-15b, miR-21, miR-31, and miR-146a-that consistently exhibit altered expression in CRC. The current knowledge of their role in key oncogenic pathways, drug resistance, and clinical relevance is discussed. Despite challenges posed by the heterogeneity of the research findings on miRNA deregulation and their role in CRC, integrating miRNA diagnostics into current screening methods holds promise for enhancing personalized medicine approaches. This review emphasizes the transformative potential of miRNAs in CRC diagnosis, paving the way for improved patient outcomes and novel therapeutic paradigms.

Serum miR-215-5p, miR-192-5p and miR-378a-5p as novel diagnostic biomarkers for periampullary adenocarcinoma

OBJECTIVE

MicroRNAs (miRNAs) are present in human serum in a stable form. Circulating miRNAs are increasingly recognized as promising biomarkers for early cancer detection. The aim of this study was to identify serum miRNAs as biomarkers for periampullary adenocarcinoma (PAC).

PATIENTS AND METHODS

68 patients with PAC and 50 healthy controls (HCs) subjects were recruited in this study. The expression levels of 11 selected miRNAs were determined in serum samples using the SYBR-green quantitative reverse transcription polymerase chain reaction (qRT-PCR) method. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic potential of serum miRNAs.

RESULTS

The expression levels of three miRNAs (miR-215-5p, miR-192-5p, and miR-378a-5p) were significantly upregulated in the serum samples derived from the PAC patients compared with those from the HC (p < 0.001). The ROC analysis showed that all three significantly altered miRNAs (miR-215-5p, miR-192-5p, and miR-378a-5p) could potentially discriminate patients with PAC from HC with AUC value of 0.771 (95% CI: 0.684-0.843), 0.877 (95% CI: 0.799-0.927) and 0.768 (95% CI: 0.674-0.853) respectively. Further comparisons showed that these three serum miRNAs (miR-215-5p, miR-192-5p, and miR-378a-5p) can strongly discriminate early-stage PAC patients from HC with an AUC value of 0.802 (95% CI: 0.719-0.886), 0.870 (95% CI: 0.793-0.974) and 0.793 (95% CI: 0.706-0.880) respectively, may aid in early detection of PAC.

CONCLUSIONS

Taken together, our findings demonstrated that these three serum miRNAs (miR-215-5p, miR-192-5p, and miR-378a-5p) may serve as noninvasive biomarkers for the early detection of PAC.

Comparison of the diagnostic value of various microRNAs in blood for colorectal cancer: a systematic review and network meta-analysis

BACKGROUND

Despite the existence of numerous studies investigating the diagnostic potential of blood microRNAs for colorectal cancer, the microRNAs under consideration vary widely, and comparative analysis of their diagnostic value is lacking. Consequently, this systematic review aims to identify the most effective microRNA blood tumor markers to enhance clinical decision-making in colorectal cancer screening.

METHOD

A comprehensive search of databases, including PubMed, Embase, Web of Science, Scopus, and Cochrane, was conducted to identify case‒control or cohort studies that examined the diagnostic value of peripheral blood microRNAs in colorectal cancer. Studies were included if they provided sensitivity and specificity data, were published in English and were available between January 1, 2000, and February 10, 2023. The Critical Appraisal Skills Programme (CASP) checklist was employed for quality assessment. A Bayesian network meta-analysis was performed to estimate combined risk ratios (RRs) and 95% confidence intervals (CIs), with results presented via rankograms. This study is registered with the International Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY), 202,380,092.

RESULTS

From an initial pool of 2254 records, 79 met the inclusion criteria, encompassing a total of 90 microRNAs. The seven most frequently studied microRNAs (43 records) were selected for inclusion, all of which demonstrated moderate to high quality. miR-23, miR-92, and miR-21 exhibited the highest sensitivity and accuracy, outperforming traditional tumor markers CA19-9 and CEA in terms of RR values and 95% CI for both sensitivity and accuracy. With the exception of miR-17, no significant difference was observed between each microRNA and CA19-9 and CEA in terms of specificity.

CONCLUSIONS

Among the most extensively researched blood microRNAs, miR-23, miR-92, and miR-21 demonstrated superior diagnostic value for colorectal cancer due to their exceptional sensitivity and accuracy. This systematic review and network meta-analysis may serve as a valuable reference for the clinical selection of microRNAs as tumor biomarkers.

Pathogenesis and biomarkers of colorectal cancer by epigenetic alteration

Colorectal cancer (CRC) ranks third in cancer incidence and stands as the second leading cause of cancer-related deaths globally. CRC tumorigenesis results from a cumulative set of genetic and epigenetic alterations, disrupting cancer-regulatory processes like cell proliferation, metabolism, angiogenesis, cell death, invasion, and metastasis. Key epigenetic modifications observed in cancers encompass abnormal DNA methylation, atypical histone modifications, and irregularities in noncoding RNAs, such as microRNAs and long noncoding RNAs. The advancement in genomic technologies has positioned these genetic and epigenetic shifts as potential clinical biomarkers for CRC patients. This review concisely covers the fundamental principles of CRC-associated epigenetic changes, and examines in detail their emerging role as biomarkers for early detection, prognosis, and treatment response prediction.

Current advances in detecting genetic and epigenetic biomarkers of colorectal cancer

Colorectal carcinoma (CRC) is the third most common cancer in terms of diagnosis and the second in terms of mortality. Recent studies have shown that various proteins, extracellular vesicles (i.e., exosomes), specific genetic variants, gene transcripts, cell-free DNA (cfDNA), circulating tumor DNA (ctDNA), microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and altered epigenetic patterns, can be used to detect, and assess the prognosis of CRC. Over the last decade, a plethora of conventional methodologies (e.g., polymerase chain reaction [PCR], direct sequencing, enzyme-linked immunosorbent assay [ELISA], microarray, in situ hybridization) as well as advanced analytical methodologies (e.g., microfluidics, electrochemical biosensors, surface-enhanced Raman spectroscopy [SERS]) have been developed for analyzing genetic and epigenetic biomarkers using both optical and non-optical tools. Despite these methodologies, no gold standard detection method has yet been implemented that can analyze CRC with high specificity and sensitivity in an inexpensive, simple, and time-efficient manner. Moreover, until now, no study has critically reviewed the advantages and limitations of these methodologies. Here, an overview of the most used genetic and epigenetic biomarkers for CRC and their detection methods are discussed. Furthermore, a summary of the major biological, technical, and clinical challenges and advantages/limitations of existing techniques is also presented.

Modulation of miR-146b Expression during Aging and the Impact of Physical Activity on Its Expression and Chondrogenic Progenitors

The finding of molecules associated with aging is important for the prevention of chronic degenerative diseases and for longevity strategies. MicroRNAs (miRNAs) are post-transcriptional regulators involved in many biological processes and miR-146b-5p has been shown to be involved in different degenerative diseases. However, miR-146b-5p modulation has not been evaluated in mesenchymal stem cells (MSCs) commitment or during aging. Therefore, the modulation of miR-146b-5p in the commitment and differentiation of mesenchymal cells as well as during maturation and aging in zebrafish model were analyzed. In addition, circulating miR-146b-5p was evaluated in human subjects at different age ranges. Thus, the role of physical activity in the modulation of miR-146b-5p was also investigated. To achieve these aims, RT (real-time)-PCR, Western blot, cell transfections, and three-dimensional (3D) culture techniques were applied. Our findings show that miR-146b-5p expression drives MSCs to adipogenic differentiation and increases during zebrafish maturation and aging. In addition, miR-146b-5p expression is higher in females compared to males and it is associated with the aging in humans. Interestingly, we also observed that the physical activity of walking downregulates circulating miR-146b-5p levels in human females and increases the number of chondroprogenitors. In conclusion, miR-146b-5p can be considered an age-related marker and can represent a useful marker for identifying strategies, such as physical activity, aimed at counteracting the degenerative processes of aging.

Cross-Kingdom Interaction of miRNAs and Gut Microbiota with Non-Invasive Diagnostic and Therapeutic Implications in Colorectal Cancer

Colorectal cancer (CRC) has one of the highest incidences among all types of malignant diseases, affecting millions of people worldwide. It shows slow progression, making it preventable. However, this is not the case due to shortcomings in its diagnostic and management procedure and a lack of effective non-invasive biomarkers for screening. Here, we discuss CRC-associated microRNAs (miRNAs) and gut microbial species with potential as CRC diagnostic and therapy biomarkers. We provide rich evidence of cross-kingdom miRNA-mediated interactions between the host and gut microbiome. miRNAs have emerged with the ability to shape the composition and dynamics of gut microbiota. Intestinal microbes can uptake miRNAs, which in turn influence microbial growth and provide the ability to regulate the abundance of various microbial species. In the context of CRC, targeting miRNAs could aid in manipulating the balance of the microbiota. Our findings suggest the need for correlation analysis between the composition of the gut microbiome and the miRNA expression profile.

Down-regulated MiRNA 29-b as a diagnostic marker in colorectal cancer and its correlation with ETV4 and Cyclin D1 immunohistochemical expression

BACKGROUND

Colorectal cancer (CRC) is the most common malignant tumor of the gastrointestinal tract with unfavorable prognosis. Therefore, novel biomarkers that may be used for new diagnostic strategies and drug-targeting therapy should be developed.

OBJECTIVES

To investigate the expression of miR-29b in CRC and its association with ETV4 and cyclin D1 expression. Moreover, the current work aims to investigate the association between them and the clinicopathological features of CRC.

METHODS

The expression of miR-29b and ETV4 (by qRT-PCR) and ETV4 and cyclin D1 (immunohistochemistry) was investigated in 65 cases of colon cancer and surrounding healthy tissues.

RESULTS

MiR-29b down-regulated and ETV4 and Cyclin D1 up-regulated significantly in colon cancer tissues compared to normal nearby colonic tissues. In addition, significant associations between ETV4 and cyclin D1 expressions and progressive stage and lymph node (LN) metastasis (P< 0.001 for each) were found. Furthermore, there was a negative correlation between miR-29b gene expression and ETV4 gene expression (r=-0.298, P<0.016).

CONCLUSION

Down-regulation of miR-29b and over-expression of ETV4 and cyclin D1 may be utilized as early diagnostic marker for development of colon cancer. ETV4 and cyclin D1 correlate with poor prognostic indicators and considered as a possible target for therapy in colon cancer.

Investigating the Role of Circulating miRNAs as Biomarkers in Colorectal Cancer: An Epidemiological Systematic Review

Colorectal cancer (CRC) is one of the most common cancers worldwide. Primary and secondary preventions are key to reducing the global burden. MicroRNAs (miRNAs) are a group of small non-coding RNA molecules, which seem to have a role either as tumor suppressor genes or oncogenes and to be related to cancer risk factors, such as obesity and inflammation. We conducted a systematic review and meta-analysis to identify circulating miRNAs related to CRC diagnosis that could be selected as biomarkers in a meet-in-the-middle analysis. Forty-four studies were included in the systematic review and nine studies in the meta-analysis. The pooled sensitivity and specificity of miR-21 for CRC diagnosis were 77% (95% CI: 69–84) and 82% (95% CI: 70–90), respectively, with an AUC of 0.86 (95% CI: 0.82–0.88). Several miRNAs were found to be dysregulated, distinguishing patients with CRC from healthy controls. However, little consistency was present across the included studies, making it challenging to identify specific miRNAs, which were consistently validated. Understanding the mechanisms by which miRNAs become biologically embedded in cancer initiation and promotion may help better understand cancer pathways to develop more effective prevention strategies and therapy approaches.

Mir-29b in Breast Cancer: A Promising Target for Therapeutic Approaches

The miR-29 family comprises miR-29a, miR-29b, and miR-29c, and these molecules play crucial and partially overlapped functions in solid tumors, in which the different isoforms are variously de-regulated and mainly correlated with tumor suppression. miR-29b is the most expressed family member in cancer, in which it is involved in regulating gene expression at both transcriptional and post-transcriptional levels. This review focuses on the role of miR-29b in breast cancer, in which it plays a controversial role as tumor suppressor or onco-miRNA. Here we have highlighted the dual effect of miR-29b on breast tumor features, which depend on the prevailing function of this miRNA, on the mature miR-29b evaluated, and on the breast tumor characteristics. Remarkably, the analyzed miR-29b form emerged as a crucial element in the results obtained by various research groups, as the most abundant miR-29b-3p and the less expressed miR-29b1-5p seem to play distinct roles in breast tumors with different phenotypes. Of particular interest are the data showing that miR-29b1-5p counteracts cell proliferation and migration and reduces stemness in breast tumor cells with a triple negative phenotype. Even if further studies are required to define exactly the role of each miR-29b, our review highlights its possible implication in phenotype-specific management of breast tumors.

Epigenetic Alteration in Colorectal Cancer: A Biomarker for Diagnostic and Therapeutic Application

Colorectal cancer (CRC) is the leading cause of cancer death worldwide. A crucial process that initiates and progresses CRC is various epigenetic and genetic changes occurring in colon epithelial cells. Recently, huge progress has been made to understand cancer epigenetics, especially regarding DNA methylation changes, histone modifications, dysregulation of miRNAs and noncoding RNAs. In the "epigenome" of colon cancer, abnormal methylation of genes that cause gene alterations or expression of miRNA has been reported in nearly all CRC; these findings can be encountered in the average CRC methylome. Epigenetic changes, known as driving events, are assumed to play a dominant part in CRC. Furthermore, as epigenetic changes in CRC become properly understood, these changes are being established as clinical biomarkers for therapeutic and diagnostic purposes. Progression in this area indicates that epigenetic changes will often be utilized in the future to prevent and treat CRC.

The Role of miR-29s in Human Cancers—An Update

MicroRNAs (miRNAs) are small non-coding RNAs that directly bind to the 3’ untranslated region (3’-UTR) of the target mRNAs to inhibit their expression. The miRNA-29s (miR-29s) are suggested to be either tumor suppressors or oncogenic miRNAs that are strongly dysregulated in various types of cancer. Their dysregulation alters the expression of their target genes, thereby exerting influence on different cellular pathways including cell proliferation, apoptosis, migration, and invasion, thereby contributing to carcinogenesis. In the present review, we aimed to provide an overview of the current knowledge on the miR-29s biological network and its functions in cancer, as well as its current and potential applications as a diagnostic and prognostic biomarker and/or a therapeutic target in major types of human cancer.

miR‑29b‑3p inhibits 22Rv1 prostate cancer cell proliferation through the YWHAE/BCL‑2 regulatory axis

Prostate cancer (PCa) is one of the most common malignant tumours in the world and seriously affects health of men. Studies have shown that microRNA (miR)-29b-3p and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein epsilon (YWHAE) play important roles in influencing the proliferation and apoptosis of PCa cells. However, the molecular mechanism of miR-29b-3p and YWHAE in the proliferation and apoptosis of PCa cells remains unclear. In the present study, bioinformatics as well as in vivo and in vitro experiments were used to predict and verify the targeting relationship between YWHAE and mir-29B-3p and investigate the potential roles of YWHAE and mir-29b-3p in the proliferation and apoptosis of 22RV1 cells. Using bioinformatics and a double luciferase system assay, it was confirmed that miR-29b-3p can target YWHAE 3′untranslated region and affect the expression of YWHAE, suggesting that miR-29b-3p may be a potential miRNA of YWHAE. Reverse transcription-quantitative PCR, Cell Counting Kit-8, Transwell and cell scratch assays showed that miR-29b-3p significantly inhibited the proliferation, invasion and migration of 22Rv1 cells (P<0.01). Rescue experiments demonstrated that YWHAE gene introduction reversed the inhibitory effect of miR-29b-3p on 22Rv1 cells. Western blotting revealed that the upregulation of miR-29b-3p inhibited YWHAE expression, resulting in a very significant decrease in the ratio of p-BAD/BAD and full-length caspase 3/cleaved caspase 3 (P<0.01) and an extremely significant increase in the ratio of BAX/BCL-2 (P<0.01). A tumourigenesis test in nude mice in vivo confirmed that the upregulation of miR-29b-3p inhibited tumour growth by targeting YWHAE. The present experiments confirmed that miR-29b-3p plays a tumour suppressor role in 22Rv1 PCa cells, and the YWHAE/BCL-2 regulatory axis plays a vital role in miR-29b-3p regulating the proliferation and apoptosis of 22Rv1 cells. These results may provide a theoretical basis for the diagnosis and targeted treatment of PCa.

Serum miR-373-3p and miR-194-5p Are Associated with Early Tumor Progression during FOLFIRINOX Treatment in Pancreatic Cancer Patients: A Prospective Multicenter Study

In this study, we explored the predictive value of serum microRNA (miRNA) expression for early tumor progression during FOLFIRINOX chemotherapy and its association with overall survival (OS) in patients with pancreatic ductal adenocarcinoma (PDAC). A total of 132 PDAC patients of all disease stages were included in this study, of whom 25% showed progressive disease during FOLFIRINOX according to the RECIST criteria. MiRNA expression was analyzed in serum collected before the start and after one cycle of chemotherapy. In the discovery cohort (n = 12), a 352-miRNA RT-qPCR panel was used. In the validation cohorts (total n = 120), miRNA expression was detected using individual RT-qPCR miRNA primers. Before the start of FOLFIRINOX, serum miR-373-3p expression was higher in patients with progressive disease compared to patients with disease control after FOLFIRINOX (Log2 fold difference (FD) 0.88, p = 0.006). MiR-194-5p expression after one cycle of FOLFIRINOX was lower in patients with progressive disease (Log2 FD -0.29, p = 0.044). Both miRNAs were predictors of early tumor progression in a multivariable model including disease stage and baseline CA19-9 level (miR-373-3p odds ratio (OR) 3.99, 95% CI 1.10-14.49; miR-194-5p OR 0.91, 95% CI 0.83-0.99). MiR-373-3p and miR-194-5p did not show an association with OS after adjustment for disease stage, baseline CA19-9, and chemotherapy response. In conclusion, high serum miR-373-3p before the start and low serum miR-194-5p after one cycle are associated with early tumor progression during FOLFIRINOX.

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.

Advances in Early Detection of Colorectal Cancer: A Focus on Non-invasive Biomarkers

BACKGROUND

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide. Currently, colonoscopy remains the gold standard diagnostic test for CRC detection. Nonetheless, this technique is invasive and expensive. Remarkable ongoing strategies are focusing on the development of affordable methods to diagnose CRC at earlier stages. The introduction of suitable noninvasive, sensitive and specified diagnostic tests for early CRC detection by employing biomarker analysis seems to be a fundamental need to reduce the numbers of unnecessary colonoscopies. In this review, we provide an overview of single- and multi-panel biomarkers (Genomic markers, transcriptome markers, proteomic markers, inflammatory markers, and microbiome markers) encompassing noninvasive tests in blood and stool for early CRC detection.

METHODS

A bibliographic search using PubMed/Medline, Web of Science, and EBSCOhost databases was performed to find relevant published studies over the last 6 years. Forty-three pertinent studies were included in this review.

RESULTS

The primary outcome highlights the sensitivity and specificity of single diagnostic biomarkers studied in blood or stool. The secondary outcome reveals the sensitivity and specificity of the biomarkers panel (combinations) in blood or stool. While some markers show better performance, others are not suitable for screening purposes.

CONCLUSION

There is a need to adjust experimental and analytical tests that can interfere with a robust result to replace or supplement those markers that are currently in use. Nevertheless, robust verification and validation with large clinical cohorts are needed for successful noninvasive tests that can fulfill the role of colonoscopy.

Overexpression of microRNA-29b inhibits epithelial-mesenchymal transition and angiogenesis of colorectal cancer through the ETV4/ERK/EGFR axis

BACKGROUND

Recent studies have reported the involvement of microRNA-29 (miR-29) family members in human cancers through their ability to regulate cellular functions. The present study investigated biological function of miR-29b in colorectal cancer (CRC).

METHODS

CRC tissues and adjacent normal tissues were collected and the expression of ETV4 and miR-29b in the tissues were identified. The relationship between ETV4 and miR-29b or ETV4 expression and the EGFR promoter was identified using dual-luciferase reporter gene and CHIP assays. The proliferation, invasion, migration, and apoptosis of CRC HCT116 cells were assayed using MTT assay, Scratch test, Transwell assay, and flow cytometry, respectively. Also, expression of epithelial-mesenchymal transition (EMT) markers, angiogenic factors, and vasculogenic mimicry formation were evaluated using RT-qPCR and Western blot.

RESULTS

ETV4 was upregulated, while miR-29b expression was decreased in CRC tissues. ETV4 was identified as a target gene of miR-29b, which in turn inactivated the ERK signaling pathway by targeting ETV4 and inhibiting EGFR transcription. Transfection with miR-29b mimic, siRNA-ETV4, or ERK signaling pathway inhibitor U0126 increased expression of E-cadherin and TSP-1, and CRC cell apoptosis, yet reduced expression of ERK1/2, MMP-2, MMP-9, Vimentin, and VEGF, as well as inhibiting EMT, angiogenesis, and CRC cell migration and invasion. The EMT, angiogenesis and cancer progression induced by miR-29b inhibitor were reversed by siRNA-mediated ETV4 silencing.

CONCLUSIONS

miR-29b suppresses angiogenesis and EMT in CRC via the ETV4/ERK/EGFR axis.

Rola miRNA w rozwoju wybranych nowotworów – potencjalne zastosowanie w diagnostyce*

MikroRNA (miRNA) są małymi cząsteczkami kwasu rybonukleinowego, które mimo że nie podlegają procesowi translacji, pełnią ważną funkcję regulacyjną w komórkach eukariotycznych. Ich fizjologiczną funkcją jest utrzymywanie homeostazy komórek. Zaburzona ekspresja miRNA może spowodować rozwój wielu chorób, w tym chorób nowotworowych. Działanie miRNA polega na hamowaniu tworzenia się białek, w tym białek o właściwościach onkogennych i antyonkogennych. Mutacje w miejscach kodowania miRNA mogą prowadzić do nadmiernego lub zmniejszonego wytwarzania wspomnianych białek. Odkrycie miRNA i poznanie ich roli w komórce otworzyło nowe możliwości dla diagnostyki chorób nowotworowych. Zmiany poziomu odpowiednich miRNA, w krwiobiegu lub innych płynach ustrojowych, mogą być markerem diagnostycznym chorób. Diagnostyka onkologiczna mogłaby przebiegać na podstawie badań profilu miRNA pacjenta i porównania go z opracowanymi wcześniej profilami zmian miRNA powiązanymi z występowaniem danego rodzaju choroby nowotworowej. Informacja o zmianach profilu miRNA podstawowych w regulacji ekspresji genów związanych z procesami nowotworzenia, mogłaby się przyczynić do opracowania terapii eksperymentalnych opartych na przywróceniu pierwotnego poziomu miRNA w komórkach, a tym samym, na przywróceniu prawidłowej regulacji ekspresji genów. Coraz nowsze metody wyciszania i włączania ekspresji miRNA mogą w przyszłości zaowocować skutecznymi rozwiązaniami terapeutycznymi.

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.

MicroRNA-29b-3p enhances radiosensitivity through modulating WISP1-mediated mitochondrial apoptosis in prostate cancer cells

Radiotherapy is frequently applied for clinically localized prostate cancer while its efficacy could be significantly hindered by radioresistance. MicroRNAs (miRNAs) are important regulators in mediating cellular responses to ionizing radiation (IR), and strongly associate with radiosensitivity in many cancers. In this study, enhancement of radiosensitivity by miR-29b-3p was demonstrated in prostate cancer cell line LNCaP in vitro. Results showed that miR-29b-3p expression was significantly upregulated in response to IR from both X-rays and carbon ion irradiations. Knockdown of miR-29b-3p resulted in radioresistance while overexpression of miR-29b-3p led to increased radiosensitivity (showing reduced cell viability, suppressed cell proliferation and decreased colony formation). In addition, miR-29b-3p was found to directly target Wnt1-inducible-signaling protein 1 (WISP1). Inhibition of WISP1 facilitated the mitochondrial apoptosis pathway through suppressing Bcl-XL expression while activating caspase-3 and poly (ADP-ribose) polymerase (PARP). The results indicated that miR-29b-3p was a radiosensitizing miRNAs and could enhance radiosensitivity of LNCaP cells by targeting WISP1. These findings suggested a novel treatment to overcome radioresistance in prostate cancer patients, especially those with higher levels of the WISP1 expression.

MicroRNA-29a functions as a tumor suppressor through targeting STAT3 in laryngeal squamous cell carcinoma

Laryngeal squamous cell carcinoma (LSCC) is a common head and neck cancer with high mortality in developing countries. A comprehensive understanding of the molecular mechanisms of tumor progression in laryngeal cancer is needed for new treatment strategies. MicroRNA-29a has been emerged as a critical miRNA in various cancers, and shown to regulate multiple oncogenic processes. In this study, we investigated the tumor suppressive role of miRNA-29a in laryngeal squamous cell carcinoma. We performed cell-based functional analysis after overexpression of miR-29a in AMC-HN-8 and HEP2 cells in vitro. It turned out that ectopic expression of miR-29a significantly inhibited cell proliferation, invasion, and migration in two LSCC cell lines (AMC-HN-8 and Hep2) in vitro. Further downstream target analysis by western blotting and luciferease reporter assay showed that overexpression of miR-29a significantly downregulated expression of STAT3, and STAT3 is a putative direct target of miR-29a in LSCC. In addition, the tumor suppressive function of miR-29a can be abrogated by forced expression of STAT3. Taken together, our data suggest that miR-29a functions as a tumor suppressor through targeting STAT3 in laryngeal squamous cell carcinoma.

miRNAs in Health and Disease: A Focus on the Breast Cancer Metastatic Cascade towards the Brain

MicroRNAs (miRNAs) are small non-coding RNAs that mainly act by binding to target genes to regulate their expression. Due to the multitude of genes regulated by miRNAs they have been subject of extensive research in the past few years. This state-of-the-art review summarizes the current knowledge about miRNAs and illustrates their role as powerful regulators of physiological processes. Moreover, it highlights their aberrant expression in disease, including specific cancer types and the differential hosting-metastases preferences that influence several steps of tumorigenesis. Considering the incidence of breast cancer and that the metastatic disease is presently the major cause of death in women, emphasis is put in the role of miRNAs in breast cancer and in the regulation of the different steps of the metastatic cascade. Furthermore, we depict their involvement in the cascade of events underlying breast cancer brain metastasis formation and development. Collectively, this review shall contribute to a better understanding of the uniqueness of the biologic roles of miRNAs in these processes, to the awareness of miRNAs as new and reliable biomarkers and/or of therapeutic targets, which can change the landscape of a poor prognosis and low survival rates condition of advanced breast cancer patients.

Functional mechanisms of miR-192 family in cancer

By growing research on the mechanisms and functions of microRNAs (miRNAs, miRs), the role of these noncoding RNAs gained more attention in healthcare. Due to the remarkable regulatory role of miRNAs, any dysregulation in their expression causes cellular functional impairment. In recent years, it has become increasingly apparent that these small molecules contribute to development, cell differentiation, proliferation, apoptosis, and tumor growth. In many studies, the miR-192 family has been suggested as a potential prognostic and diagnostic biomarker and even as a possible therapeutic target for several cancers. However, the mechanistic effects of the miR-192 family on cancer cells are still controversial. Here, we have reviewed each family member of the miR-192 including miR-192, miR-194, and miR-215, and discussed their mechanistic roles in various cancers.

MicroRNAs in Colon and Rectal Cancer - Novel Biomarkers from Diagnosis to Therapy

Colorectal cancer (CRC) is one of the most common cancers and a significant cause of tumor- related deaths worldwide. Traditional biomarkers, such as CEA and CA199, are not sensitive enough to provide useful information for early diagnosis and treatment and are rather used to track the clinical progression of the disease. There is growing evidence that microRNAs (miRNA) are potentially superior to traditional biomarkers as promising non-invasive biomarkers for the timely diagnosis and prediction of prognosis or treatment response in the management of CRC. In this review, the latest studies on the dysregulation of miRNAs expression in CRC and the potential for miRNAs to serve as biomarkers were collected. Given the limitations of miRNA, as discussed in this paper, its clinical applications as a diagnostic biomarker should be limited to use in combination with other biomarkers. Further research is necessary to elucidate the clinical applications of miRNA in therapy for CRC.

3D Cell Culture-Based Global miRNA Expression Analysis Reveals miR-142-5p as a Theranostic Biomarker of Rectal Cancer Following Neoadjuvant Long-Course Treatment

Altered expression of miRNAs in tumor tissue encourages the translation of this specific molecular pattern into clinical practice. However, the establishment of a selective biomarker signature for many tumor types remains an inextricable challenge. For this purpose, a preclinical experimental design, which could maintain a fast and sensitive discovery of potential biomarkers, is in demand. The present study suggests that the approach of 3D cell cultures as a preclinical cancer model that is characterized to mimic a natural tumor environment maintained in solid tumors could successfully be employed for the biomarker discovery and validation. Subsequently, in this study, we investigated an environment-dependent miRNA expression changes in colorectal adenocarcinoma DLD1 and HT29 cell lines using next-generation sequencing (NGS) technology. We detected a subset of 16 miRNAs differentially expressed in both cell lines cultivated in multicellular spheroids compared to expression levels in cells grown in 2D. Furthermore, results of in silico miRNA target analysis showed that miRNAs, which were differentially expressed in both cell lines grown in MCS, are involved in the regulation of molecular mechanisms implicated in cell adhesion, cell-ECM interaction, and gap junction pathways. In addition, integrins and platelet-derived growth factor receptors were determined to be the most significant target genes of deregulated miRNAs, which was concordant with the environment-dependent gene expression changes validated by RT-qPCR. Our results revealed that 3D microenvironment-dependent deregulation of miRNA expression in CRC cells potentially triggers essential molecular mechanisms predominantly including the regulation of cell adhesion, cell-cell, and cell-ECM interactions important in CRC initiation and development. Finally, we demonstrated increased levels of selected miR-142-5p in rectum tumor tissue samples after neoadjuvant long course treatment compared to miR-142-5p expression levels in tumor biopsy samples collected before the therapy. Remarkably, the elevation of miR-142-5p expression remained in tumor samples compared to adjacent normal rectum tissue as well. Therefore, the current study provides valuable insights into the molecular miRNA machinery of CRC and proposes a potential miRNA signature for the assessment of CRC in further clinical research.

Downregulation of circulating miR 802-5p and miR 194-5p and upregulation of brain MEF2C along breast cancer brain metastasization

Breast cancer brain metastases (BCBMs) have been underinvestigated despite their high incidence and poor outcome. MicroRNAs (miRNAs), and particularly circulating miRNAs, regulate multiple cellular functions, and their deregulation has been reported in different types of cancer and metastasis. However, their signature in plasma along brain metastasis development and their relevant targets remain undetermined. Here, we used a mouse model of BCBM and next‐generation sequencing (NGS) to establish the alterations in circulating miRNAs during brain metastasis formation and development. We further performed bioinformatics analysis to identify their targets with relevance in the metastatic process. We additionally analyzed human resected brain metastasis samples of breast cancer patients for target expression validation. Breast cancer cells were injected in the carotid artery of mice to preferentially induce metastasis in the brain, and samples were collected at different timepoints (5 h, 3, 7, and 10 days) to follow metastasis development in the brain and in peripheral organs. Metastases were detected from 7 days onwards, mainly in the brain. NGS revealed a deregulation of circulating miRNA profile during BCBM progression, rising from 18% at 3 days to 30% at 10 days following malignant cells’ injection. Work was focused on those altered prior to metastasis detection, among which were miR‐802‐5p and miR‐194‐5p, whose downregulation was validated by qPCR. Using targetscan and diana tools, the transcription factor myocyte enhancer factor 2C (MEF2C) was identified as a target for both miRNAs, and its expression was increasingly observed in malignant cells along brain metastasis development. Its upregulation was also observed in peritumoral astrocytes pointing to a role of MEF2C in the crosstalk between tumor cells and astrocytes. MEF2C expression was also observed in human BCBM, validating the observation in mouse. Collectively, downregulation of circulating miR‐802‐5p and miR‐194‐5p appears as a precocious event in BCBM and MEF2C emerges as a new player in brain metastasis development.

The Diagnostic Value of MicroRNAs as a Biomarker for Hepatocellular Carcinoma: A Meta-Analysis

BACKGROUND

Recently, the role of microRNAs (miRNAs) in diagnosing cancer has been attracted increasing attention. However, few miRNAs have been applied in clinical practice. The purpose of this study was to evaluate the diagnostic efficacy of miRNAs for hepatocellular carcinoma (HCC) at early stages clinically.

METHODS

A literature search was carried out using PubMed, Web of Science, and EMBASE databases. We explored the diagnostic value of miRNAs in distinguishing HCC from healthy individuals. The quality assessment was performed in Review Manager 5.3 software. The overall sensitivity and specificity and 95% confidence intervals (CIs) were obtained with random-effects models through Stata 14.0 software. And heterogeneity was assessed using Q test and I 2 statistics. Meta-regression and subgroup analyses were conducted based on the sample, nation, quality of studies, and miRNA profiling. The publication bias was evaluated through Deeks' funnel plot.

RESULTS

A total of 34 studies, involving in 2747 HCC patients and 2053 healthy individuals, met the inclusion criteria in the 33 included literature studies. In the summary receiver operating characteristic (sROC) curve, AUC was 0.92 (95% CI, 0.90-0.94), with 0.84 (95% CI, 0.79-0.88) sensitivity and 0.87 (95% CI, 0.83-0.90) specificity. There was no publication bias (P=0.48).

CONCLUSION

miRNAs in vivo can be acted as a potential diagnostic biomarker for HCC, which can facilitate the early diagnosis of HCC in clinical practice.

Roles of microRNAs as non-invasive biomarker and therapeutic target in colorectal cancer

MicroRNAs are endogenous, short non-coding RNA molecules that function as critical regulators of various biological processes. There is a strong functional evidence linking the involvement of dysregulated miRNAs to the occurrence, development and progression of colorectal cancer. Studies indicate that while overexpression of oncomiRs, and repression of tumor suppressor miRNAs tends to drive the overall tumorigenic process, the global picture of aberrant miRNA expression in colorectal cancer can classify the disease into multiple molecular phenotypes. Moreover, the expression pattern of miRNAs in colorectal cancer make them viable disease determinants as well as potential therapeutic targets. Through this review, we will summarize the importance of miRNAs in the etiology and progression of colorectal cancer. Specifically, we will explore the key role played by these RNA molecules as likely therapeutic avenues and the strategies presently available to target them. Finally, we will investigate the role of miRNAs as potential non-invasive diagnostic and prognostic biomarkers in colorectal cancer.

Integrated analyses of microRNA-29 family and the related combination biomarkers demonstrate their widespread influence on risk, recurrence, metastasis and survival outcome in colorectal cancer

Background

Emerging evidence has revealed miR-29 family as promising biomarkers for colorectal cancer (CRC), but their biomarker potential and molecular mechanisms remain poorly understood.

Methods

We performed a comprehensive meta-analysis to evaluate the biomarker performance of individual miR-29 and the related miRNA combination biomarkers. Meanwhile, we conducted an integrative bioinformatics analysis to unfold the underlying biological function of miR-29 and their relationship with CRC.

Results

Using miR-29 expression to diagnose CRC produced 0.82 area under the curve, 70% sensitivity and 81% specificity while the combination biomarkers based on miR-29 enhanced the diagnostic power with an AUC of 0.86, a sensitivity of 78% and a specificity of 91%. For the prognosis evaluation, patients with higher expression of miR-29 had better survival outcome (pooled HR 0.78; 95% CI 0.56–1.07). In addition, miR-29 has also been identified as potential biomarker for predicting recurrence and metastasis in CRC. Then the genes regulated by the miR-29 family were retrieved and found closely associated with the molecular pathogenesis of CRC according to the gene ontology and pathway analysis. Furthermore, hub nodes and significant modules were identified from the protein–protein interaction network constructed with miR-29 family targets, which were also confirmed highly involved in the establishment and development of CRC.

Conclusions

Current evidences suggest miR-29 family may become promising biomarkers for risk, recurrence, metastasis and survival outcome of CRC. Meanwhile our data highlight the potential clinical use of miRNA combination biomarkers. Nevertheless, further prospective studies are warranted before the application of the useful biomarkers in the clinical.

Circulating microRNAs as Promising Biomarkers in Colorectal Cancer

Colorectal cancer (CRC) is one of the most common cancers and a leading cause of cancer-related deaths worldwide. Despite numerous advances in therapeutic approaches, this cancer has a poor prognosis when it is diagnosed at late stages. Therefore, the scientific effort is nowadays directed towards the development of new non-invasive and dynamic biomarkers to improve the survival expectancy of CRC patients. In this sense, deregulated expression of many miRNAs has been shown to play an important role for CRC carcinogenesis and dissemination. Noticeably, an increasing number of studies highlight that circulating miRNAs, including those traveling inside exosomes or those released by tumor cells into circulation, constitute a promising tool for early detection, prognosis and therapy selection of CRC. Therefore, in this review we focus on the clinical potential of blood circulating miRNAs as emerging biomarkers with high value to improve the clinical management of CRC patients, providing a deep and complete perspective of the realities and challenges to translate these biomarkers to the clinical context.

Therapeutic Delivery of miR-29b Enhances Radiosensitivity in Cervical Cancer

Radioresistant cervical cancer is likely to give rise to local recurrence, distant metastatic relapse, and decreased survival rates. Recent studies revealed microRNA mediated regulation of tumor aggressiveness and metastasis; however, whether specific microRNAs regulate tumor radioresistance and can be exploited as radiosensitizing agents remains unclear. Here, we find that miR-29b could promote radiosensitivity in radioresistant subpopulations of cervical cancer cells. Notably, therapeutic delivery of miR-29b mimics via R11-SSPEI nanoparticle, whose specificity has been proved by our previous studies, can sensitize the tumor to radiation in a xenograft model. Mechanistically, we reveal a novel function of miR-29b in regulating intracellular reactive oxygen species signaling and explore a potential application for its use in combination with therapies known to increase oxidative stress such as radiation. Moreover, miR-29b inhibits DNA damage repair by targeting phosphate and tension homology deleted on chromsome ten (PTEN), and overexpression of PTEN could partially rescue miR-29b-mediated homologous recombination (HR)-DNA damage repair and increase radiosensitivity. These findings identify miR-29b as a radiosensitizing microRNA and reveal a new therapeutic strategy for radioresistant tumors.

Circulating Noncoding RNAs Have a Promising Future Acting as Novel Biomarkers for Colorectal Cancer

Colorectal cancer (CRC) is one of the most common malignant tumors worldwide, causing a large number of cancer-related deaths each year. Patients are usually diagnosed at advanced and incurable stages due to the lack of suitable screening methods for early detection. Noncoding RNAs (ncRNAs), including small and long noncoding RNAs (lncRNA), are known to have significant regulatory functions, and accumulating evidence suggests that circulating ncRNAs have potential applications as noninvasive biomarkers for diagnosing CRC, evaluating its prognosis, or predicting chemosensitivity in the general population. In this review, we summarize the origins of circulating ncRNAs and provide details of single and multiple circulating ncRNAs that might have roles as diagnostic and prognostic biomarkers in CRC. We end by discussing circulating ncRNAs that may distinguish patients with resistance to chemotherapy.

Plasma Level of MicroRNAs, MiR-107, MiR-194 and MiR-210 as Potential Biomarkers for Diagnosis Intestinal-Type Gastric Cancer in Human

Background:

Timely and sensitive diagnosis of gastric cancer is crucial for efficient treatment and survival of the patients. microRNAs have been considered as diagnostic biomarkers in different type of cancers including gastric cancer. In the present study, the expression profile of four microRNAs, miR-103, miR-107, miR-194 and miR-210 were evaluated in patients with intestinal-type of gastric cancer (IGC) in order to assess their diagnosis utility as noninvasive biomarkers.

Methods:

A total number of 100 plasma samples from patients with gastric cancer and healthy controls were obtained and total RNA was extracted using a commercial monophasic solution of phenol and guanidium thiocyanate. Reverse transcription (RT) reactions were performed by specific stem-loop RT primers and M-MuLV RT-enzyme. The expression patterns of microRNAs were assessed using reverse transcription quantitative real-time PCR (RT-qPCR) method and the expression of SNORD47 RNA was used as the reference for normalization.

Results:

The results indicate that the plasma levels of miR-107, miR-194, and miR-210 were significantly lower in patients. Receiver operating characteristic (ROC) curve analysis showed that the patients could be distinguished from healthy individuals at the cutoff levels of 0.504, 0.266, and 0.394 of miR-107, miR-194, and miR-210, respectively. On the other hand, the expression levels of these miRNAs were not significantly different in different clinicopathological stages of the disease.

Conclusion:

These findings suggest that the plasma levels of miR-107, miR-194 and miR-210 were downregulated in patients with ICG and propose these molecules as potential non-invasive biomarkers for detection of IGC.

Genetic and molecular origins of colorectal Cancer among the Iranians: an update

BACKGROUND

Colorectal cancer (CRC) is one the leading causes of cancer related deaths among Iranians. Despite the various progresses in new therapeutic methods, it has still a low rate of survival. This high ratio of mortality is mainly related to the late diagnosis, in which the patients refer for treatment in advanced stages of tumor. MAIN BODY: colorectal cancer progression is largely associated with molecular and genetic bases. Although Iran has a high ratio of CRC mortality, there is not an efficient genetic panel for detection and prognosis. Therefore, it is critical to introduce new diagnostic markers with ability to detect in early stages.

CONCLUSION

Present review summarizes all of the genetic and epigenetic factors which are reported in CRC until now among the Iranian patients to pave the way of incorporation of new ethnic specific markers into the clinical practice and development of new targeted therapeutic methods.

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.

MicroRNAs, long noncoding RNAs, and circular RNAs: potential tumor biomarkers and targets for colorectal cancer

Noncoding RNAs (ncRNAs) can be divided into microRNAs (miRNAs), long noncoding RNAs (lncRNAs), circular RNAs (circRNAs), pRNAs, and tRNAs. Traditionally, miRNAs exert their biological function mainly through the inhibition of translation via the induction of target RNA transcript degradation. lncRNAs and circRNAs were once considered to have no potential to code proteins. Here, we will review the current knowledge on ncRNAs in relation to their origins, characteristics, and functions. We will also review how ncRNAs work as competitive endogenous RNA, gene transcription and expression regulators, and RNA-binding protein sponges in colorectal cancer (CRC). Notably, except for the abovementioned mechanisms, recent advances revealed that lncRNAs can also act as the precursor of miRNAs, and a small portion of lncRNAs and circRNAs was verified to have the potential to code proteins, providing new evidence for the significance of ncRNAs in CRC tumorigenesis and development.

Systematic review of blood diagnostic markers in colorectal cancer

The purpose of this systematic review was to compare the diagnostic ability of blood markers for colorectal cancer (CRC). A systematic review of the literature for diagnostic blood markers for primary human colorectal cancer over the last 5 years was performed. The primary outcome was to assess the diagnostic ability of these markers in diagnosing colorectal cancer. The secondary outcome was to see whether the marker was compared to other markers. The tertiary outcome was to assess diagnostic ability in early versus late CRC, including stage IV disease. We identified 51 studies (29 prospective, 14 retrospective, and 8 meta-analyses). The markers were divided in broadly four groups: nucleic acids (RNA/DNA/messenger RNA/microRNAs), cytokines, antibodies, and proteins. The most promising circulating markers identified among the nucleid acids were NEAT_v2 non-coding RNA, SDC2 methylated DNA, and SEPT9 methylated DNA. The most promising cytokine to detect CRC was interleukin 8, and the most promising circulating proteins were CA11-19 glycoprotein and DC-SIGN/DC-SIGNR. Sensitivities of these markers for detecting primary colorectal carcinoma ranged from 70 to 98% and specificities from 84 to 98.7%. The best studied blood marker was SEPT9 methylated DNA, which showed great variability with sensitivities ranging from 48.2 to 95.6% and specificities from 80 to 98.9%, making its clinical applicability challenging. If combined with fecal immunochemical test (FIT), the sensitivity improved from 78 to 94% in detecting CRC. Methylated SEPT9, methylated SDC2, and -SIGN/DC-SIGNR protein had better sensitivity and specificity than CEA or CA 19-9. With the exception of SEPT9 which is currently being implemented as a screening test for CRC all other markers lacked reproducibility and standardization and were studied in relatively small population samples.

MicroRNAs as potential liquid biopsy biomarkers in colorectal cancer: A systematic review

Emerging evidence has demonstrated the feasibility of circulating miRNAs as robust non-invasive biomarkers for the diagnosis in colorectal cancer. The use of circulating miRNAs for the early detection of colorectal cancer (CRC) is of particular interest as it can offer a potential complementary approach to screening colonoscopy. However, the development of circulating miRNAs as "liquid biopsy" biomarkers for development into clinical screening tests has been hampered by several issues. In this article, we summarize the status of this field for the clinical utilization of miRNA biomarkers as liquid biopsies in colorectal cancer (CRC) and discuss their applications as screening tests for patients with colorectal adenoma (CRA) and CRC. Herein, we undertook a systematic search for citations in PubMed and the Cochrane Database from January 1, 2002 through December 31, 2017 as electronic sources for this study. All published studies were screened with no restriction on language, date, or country. We used database-specific combinations of the following index terms and text words, including: microRNA, colorectal cancer, serum, plasma, and exosomes. Based upon these searches, we summarize the progress and salient features of the current state of knowledge of miRNA diagnostic biomarkers in CRC, and focuses on the articles that attempt to optimize ideal methodologies to further advance their as liquid biopsies for clinical use. We conclude that the field of noncoding RNAs, particularly for the clinical use of miRNAs as liquid biopsy assays is maturing rapidly, and it is highly promising that these genomic signatures will likely be developed into clinically-viable tests for the early detection and clinical management of patients with colorectal cancer in the not so distant future.

Prognostic value of microRNAs in colorectal cancer: a meta-analysis

Background

Numerous studies have shown that miRNA levels are closely related to the survival time of patients with colon, rectal, or colorectal cancer (CRC). However, the outcomes of different investigations have been inconsistent. Accordingly, a meta-analysis was conducted to study associations among the three types of cancers.

Materials and methods

Studies published in English that estimated the expression levels of miRNAs with survival curves in CRC were identified until May 20, 2017 by online searches in PubMed, Embase, Web of Science, and the Cochrane Library by two independent authors. Pooled HRs with 95% CIs were used to estimate the correlation between miRNA expression and overall survival.

Results

A total of 63 relevant articles regarding 13 different miRNAs, with 10,254 patients were ultimately included. CRC patients with high expression of blood miR141 (HR 2.52, 95% CI 1.68-3.77), tissue miR21 (HR 1.31, 95% CI 1.12-1.53), miR181a (HR 1.52, 95% CI 1.26-1.83), or miR224 (HR 2.12, 95% CI 1.04-4.34), or low expression of tissue miR126 (HR 1.55, 95% CI 1.24-1.93) had significantly poor overall survival (P<0.05).

Conclusion

In general, blood miR141 and tissue miR21, miR181a, miR224, and miR126 had significant prognostic value. Among these, blood miR141 and tissue miR224 were strong biomarkers of prognosis for CRC.

Identification of a circulating microRNA signature to distinguish recurrence in breast cancer patients

There is an urgent need for novel noninvasive prognostic biomarkers for monitoring the recurrence of breast cancer. The purpose of this study is to identify circulating microRNAs that can predict breast cancer recurrence. We conducted a microRNA profiling experiment in serum samples from 48 breast cancer patients using Exiqon miRCURY microRNA RT-PCR panels. Significantly differentiated miRNAs for recurrence in the discovery profiling were further validated in an independent set of sera from 20 patients with breast cancer recurrences and 22 patients without recurrences. We identified seven miRNAs that were differentially expressed between breast cancer patients with and without recurrences, including four miRNAs upregulated (miR-21-5p, miR-375, miR-205-5p, and miR-194-5p) and three miRNAs downregulated (miR-382-5p, miR-376c-3p, and miR-411-5p) for recurrent patients. Using penalized logistic regression, we built a 7-miRNA signature for breast cancer recurrence, which had an excellent discriminating capacity (concordance index=0.914). This signature was significantly associated with recurrence after adjusting for known prognostic factors, and it was applicable to both hormone-receptor positive (concordance index=0.890) and triple-negative breast cancers (concordance index=0.942). We also found the 7-miRNA signature were reliably measured across different runs of PCR experiments (intra-class correlation coefficient=0.780) and the signature was significantly higher in breast cancer patients with recurrence than healthy controls (p=1.1×10⁻⁵). In conclusion, circulating miRNAs are promising biomarkers and the signature may be developed into a minimally invasive multi-marker blood test for continuously monitoring the recurrence of breast cancer. It should be further validated for different subtypes of breast cancers in longitudinal studies.

Secretory microRNAs as biomarkers of cancer

MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression predominantly by inhibiting transcription and/or promoting degradation of target mRNAs also in addition to being involved in non-canonical mechanisms regulating transcription, translation and cell signaling processes. Extracellular secretory miRNAs, either in complex with specific proteins or encapsulated in microvesicles called exosomes, are transported between cells as means of intercellular communication. Secretory miRNAs in circulation remain functional after delivery to recipient cells, regulating target genes and their corresponding signaling pathways. Cancer cell secreted miRNA-mediated intercellular communication affects physiological processes associated with the disease, such as, angiogenesis, metabolic reprogramming, immune modulation, metastasis, and chemo-resistance. Given the stability of miRNAs in body fluids and their well-documented roles in deregulating cancer-relevant genetic pathways, there is considerable interest in developing secretory miRNAs as liquid biopsy biomarkers for detection, diagnosis and prognostication of cancer. In this review, we discuss salient features of miRNA biogenesis, secretion and function in cancer as well as the current state of secretory miRNA isolation and profiling methods. Furthermore, we discuss the challenges and opportunities of secretory miRNA biomarker assay development, which need to be addressed for clinical applications.

Overexpression of miR-194 Reverses HMGA2-driven Signatures in Colorectal Cancer

Colorectal cancer (CRC) is one of the leading causes of cancer death worldwide with increasing incidence and mortality in developed countries. Oncogenes and microRNAs regulate key signaling pathways in CRC and are known to be deregulated. Oncogenic transcriptional regulator high-mobility group AT-hook 2 (HMGA2) participates in the transformation of several cancers including CRC and exhibits strong correlation with poor prognosis and distal metastasis. Evidence of HMGA2 and its co-regulated miRs contributing to tumor progression remains to be clarified.

METHODS

We performed gene-set enrichment analysis on the expression profiles of 70 CRC patients and revealed HMGA2 correlated genes that are targeted by several miRs including miR-194. To eliminate the oncogenic effects in HMGA2-driven CRC, we re-expressed miR-194 and found that miR-194 functions as a tumor suppressor by reducing cell proliferation and tumor growth in vitro and in vivo.

RESULTS

As a direct upstream inhibitory regulator of miR-194, overexpression of HMGA2 reduced miR-194 expression and biological activity, whereas re-expressing miR-194 in cells with high levels of HMGA2 impaired the effects of HMGA2, compromising cell survival, the epithelial-mesenchymal transition process, and drug resistance.

CONCLUSION

Our findings demonstrate that novel molecular correlations can be discovered by revisiting transcriptome profiles. We uncover that miR-194 is as important as HMGA2, and both coordinately regulate the oncogenesis of CRC with inverted behaviors, revealing alternative molecular therapeutics for CRC patients with high HMGA2 expression.

Non-coding RNAs as a new dawn in tumor diagnosis

The current knowledge about non-coding RNAs (ncRNAs) as important regulators of gene expression in both physiological and pathological conditions, has been the main engine for the design of innovative platforms to finalize the pharmacological application of ncRNAs as either therapeutic tools or as molecular biomarkers in cancer. Biochemical alterations of cancer cells are, in fact, largely supported by ncRNA disregulation in the tumor site, which, in turn, reflects the cancer-associated specific modification of circulating ncRNA expression pattern. The aim of this review is to describe the state of the art of pre-clinical and clinical studies that analyze the involvement of miRNAs and lncRNAs in cancer-related processes, such as proliferation, invasion and metastases, giving emphasis to their functional role. A central node of our work has been also the examination of advantages and criticisms correlated with the clinical use of ncRNAs, taking into account the pressing need to refine the profiling methods aimed at identify novel diagnostic and prognostic markers and the request to optimize the delivery of such nucleic acids for a therapeutic use in an imminent future.

Systematic literature review and clinical validation of circulating microRNAs as diagnostic biomarkers for colorectal cancer

Because patients with colorectal cancer (CRC) are usually diagnosed at an advanced stage and current serum tumor markers have limited diagnostic efficacy, there is an urgent need to identify reliable diagnostic biomarkers. To better define the diagnostic potential of microRNAs (miRNAs) for CRC, we performed a comprehensive evaluation of reported circulating CRC miRNA markers. After a systematic literature review, we selected 30 candidate miRNAs and used quantitative real-time polymerase chain reaction to examine their expression in a training cohort of 120 plasma samples (CRC vs healthy controls (HC) = 60:60). Expression data was confirmed in a validation cohort of 160 plasma samples (CRC vs HC = 80:80). We ultimately identified 5 dysregulated circulating miRNAs (miR-15b, miR-17, miR-21, miR-26b, and miR-145), of which miR-21 and miR-26b proved to have the best diagnostic performance in the training and validation cohorts, respectively. Based on these results, we propose a novel blood-based diagnostic model, integrating 5 CRC-related miRNAs and serum carcinoembryonic antigen (CEA), which provides better diagnostic performance than the combined 5 miRNAs, CEA alone, or any single miRNA. We propose that the novel CRC diagnostic model presented here will be useful for overcoming the limitations faced by current non-invasive diagnostic strategies.

Genetic and epigenetic markers in colorectal cancer screening: recent advances

INTRODUCTION

Colorectal cancer (CRC) is a heterogenous disease which develops from benign intraepithelial lesions known as adenomas to malignant carcinomas. Acquired alterations in Wnt signaling, TGFβ, MAPK pathway genes and clonal propagation of altered cells are responsible for this transformation. Detection of adenomas or early stage cancer in asymptomatic patients and better prognostic and predictive markers is important for improving the clinical management of CRC. Area covered: In this review, the authors have evaluated the potential of genetic and epigenetic alterations as markers for early detection, prognosis and therapeutic predictive potential in the context of CRC. We have discussed molecular heterogeneity present in CRC and its correlation to prognosis and response to therapy. Expert commentary: Molecular marker based CRC screening methods still fail to gain trust of clinicians. Invasive screening methods, molecular heterogeneity, chemoresistance and low quality test samples are some key challenges which need to be addressed in the present context. New sequencing technologies and integrated omics data analysis of individual or population cohort results in GWAS. MPE studies following a GWAS could be future line of research to establish accurate correlations between CRC and its risk factors. This strategy would identify most reliable biomarkers for CRC screening and management.

Circulating miR-1826 in plasma correlates with circulating tumor cells and is a prognostic marker in colorectal cancer

Our previous study showed that miR-1826 was a newly identified oncogenic non-coding RNA in colorectal cancer. But the potential relationship between miR-1826 and tumor metastasis has not been fully elucidated. The purpose of this study was to evaluate the clinical significance of circulating miR-1826 and its possible associations with circulating tumor cells in colorectal cancer. Our results first found that serum miR-1826 was significantly upregulated in colorectal cancer patients, compared with that in healthy volunteers ( p = 0.003). Similar results were also found in colorectal cancer with distant metastasis ( p = 0.001) and advanced colorectal cancer ( p < 0.001) patients, respectively. Clinicopathological analysis implied that circulating miR-1826 was positively associated with pT stage ( p = 0.026), lymphatic metastasis ( p = 0.034), distant metastasis ( p = 0.012), and tumor-node-metastasis stage ( p = 0.020). Besides, our univariate and multivariate analyses demonstrated that high serum miR-1826 expression could act as a prognostic and independent factor for overall survival of colorectal cancer patients ( p < 0.05), which led to a poorer 5-year overall survival rate ( p = 0.025). The area under the curve value of circulating miR-1826 was up to 0.848 ± 0.043, which strongly suggested serum miR-1826 as an effective diagnostic biomarker in colorectal cancer patients ( p < 0.001). Our subsequent experiments demonstrated that patients with high level of circulating tumor cells showed a higher level of miR-1826 expression, compared with the circulating tumor cell-negative patients ( p = 0.011). Similar results also showed that the amount of circulating tumor cells in high miR-1826 group was significantly higher than that in low miR-1826 group ( p = 0.001). Furthermore, the relationship between serum miR-1826 and circulating tumor cells was analyzed using SPSS software and a significant logarithmic relationship was found, which meant that circulating miR-1826 closely correlated with the amount of circulating tumor cells in colorectal cancer patient serum ( r = 0.283, p < 0.01). Our findings strongly suggested that serum miR-1826 could serve as an effective and non-invasive biomarker for diagnosis and prognosis of colorectal cancer. Circulating miR-1826 may be an important target in colorectal cancer therapy.

Blood-based microRNAs as biomarkers for the diagnosis of colorectal cancer: a systematic review and meta-analysis

Background:

Colorectal cancer (CRC) is common and associated with significant mortality. Current screening methods for CRC lack patient compliance. microRNAs (miRNAs), identified in body fluids, are negative regulators of gene expression and are dysregulated in many cancers, including CRC. This paper summarises studies identifying blood-based miRNAs dysregulated in CRC compared with healthy controls in an attempt to evaluate their use as a screening tool for the diagnosis of CRC.

Methods:

A search of electronic databases (PubMed and EMBASE) and grey literature was performed between January 2002 and April 2016. Studies reporting plasma or serum miRNAs in the diagnosis of CRC compared with healthy controls were selected. Patient demographics, type of patient sample (serum or plasma), method of miRNA detection, type of normalisation, and the number of significantly dysregulated miRNAs identified were recorded. Statistical evaluation of dysregulated miRNAs using sensitivity, specificity, and area under the curve (AUC) was performed.

Results:

Thirty-four studies investigating plasma or serum miRNAs in the diagnosis of CRC were included. A total of 31 miRNAs were found to be either upregulated (n=17) or downregulated (n=14) in CRC cases as compared with controls. Fourteen studies identified panels of ⩾2 dysregulated miRNAs. The highest AUC, 0.943, was identified using a panel of 4 miRNAs with 83.3% sensitivity and 93.1% specificity. Meta-analysis of studies identifying a single dysregulated miRNA in CRC cases compared with controls was performed. Overall sensitivity and specificity of 28 individual miRNAs in the diagnosis of CRC were 76% (95% CI 72%–80%) and 76% (95% CI 72%–80%), respectively, indicating good discriminative ability of miRNAs as biomarkers for CRC. These data did not change with sensitivity analyses.

Conclusions:

Blood-based miRNAs distinguish patients with CRC from healthy controls with high sensitivity and specificity comparable to other common and invasive currently used screening methods for CRC. In future, miRNAs may be used as a relatively non-invasive blood-based marker for detection of CRC.