Circulating microRNA-92a-3p in colorectal cancer: a review

The role of tumor-associated fibroblast-derived exosomes in chemotherapy resistance of colorectal cancer and its application prospect

Colorectal cancer (CRC) is the second most common malignant tumor in the world. With its increasing incidence and younger age trend, its impact on human health has been paid more and more attention. Currently, we have a variety of chemotherapy drugs that can be used to treat colorectal cancer. However, the drug resistance of colorectal cancer has become a significant factor affecting its cure rate. Some studies have reported that exosomes are related to the occurrence of drug resistance. However, the exact mechanism is not precise. Therefore, we focused on the role of cancer associated-fibroblast-derived (CAFs-derived) exosomes in colorectal progression. It was found that cancer cells transmit information through exosome interaction and induce chemotherapy resistance by promoting epithelial-mesenchymal transition (EMT), up-regulating the Wnt/β-catenin signaling pathway, transforming growth factor-β1 (TGF-β1) pathway, promoting angiogenesis and other possible molecular mechanisms. In addition, in terms of clinical significance and therapeutic strategies, we explore the clinical relevance of CAFs-derived exosomes in colorectal cancer patients and their potential as potential biomarkers for predicting chemotherapy response. We also provide a new possible direction for overcoming chemotherapy resistance in colorectal cancer by targeting CAFs-derived exosomes.

Noncoding RNA (ncRNA)-mediated regulation of TLRs: critical regulator of inflammation in tumor microenvironment

Toll-like receptors (TLRs) are central components of the innate immune system as they recognize molecular patterns associated with pathogens and cellular damage and initiate immune responses using MyD88- and TRIF-dependent pathways. In contrast to being very useful for immune defense, dysregulated TLR signaling may be involved in diseases, such as cancer and autoimmune conditions. In cancer, TLRs create an environment that supports tumorigenesis and growth. In addition to this, a class of multifunctional noncoding RNAs (ncRNAs), including miRNAs, lncRNAs, and circRNAs, regulate gene expression without encoding proteins. MiRNAs regulate gene expression in a fine-tuned manner, while lncRNAs and circRNAs do so via diverse mechanisms. Notably, these ncRNAs interact, where lncRNAs and circRNAs function as competing endogenous RNAs and ceRNA, affecting miRNA activity. This interaction has a vital role in cancer pathology, in influencing that of various oncogenes and tumor suppressors in the tumor microenvironment; hence, modulation of ncRNAs could also be a great promising therapeutic approach. In this context, interplay between TLRs and ncRNAs is of paramount importance as they influence various parameters of the tumor microenvironment. TLR signaling works upon the expression of ncRNAs, while ncRNAs work back to regulate TLR signaling in return. An example of this includes miRNA targeting of components of the TLR; lncRNAs induced by TLR signaling possibly would favor tumor progression. Pharmacological interventions directed toward inhibiting these TLR pathways could be the model to halt malignancy by hampering pro-tumor inflammation and boosting immune responses against neoplasms. Hence, the review will highlight the complicated contrast of ncRNAs and TLRs within human cancer. By connecting the mechanisms, the researchers may study more about tumorigenesis and gather up new, innovative notions regarding therapeutic targeting.

Cancer-specific risk prediction with a serum microRNA signature

We recently derived and validated a serum-based microRNA risk score (miR-score) that predicted colorectal cancer (CRC) occurrence with very high accuracy within 14 years of follow-up in a population-based cohort study from Germany (ESTHER cohort). Here, we aimed to evaluate associations of the CRC-specific miR-score with the risk of developing other common cancers, including female breast cancer (BC), lung cancer (LC), and prostate cancer (PC), in the ESTHER cohort. MicroRNAs (miRNAs) were profiled by quantitative real-time PCR in serum samples collected at baseline from randomly selected incident cases of BC (n = 90), LC (n = 88), and PC (n = 93) and participants without diagnosis of CRC, LC, BC, or PC (controls, n = 181) until the end of the 17-year follow-up. Multivariate logistic regression models were used to evaluate the associations of the miR-score with BC, LC, and PC incidence. The miR-score showed strong inverse associations with BC and LC incidence [odds ratio per 1 standard deviation increase: 0.60 (95% confidence interval [CI] 0.43-0.82), p = 0.0017, and 0.64 (95% CI 0.48-0.84),p = 0.0015, respectively]. Associations with PC were not statistically significant but pointed in the positive direction. Our study highlights the potential of serum-based miRNA biomarkers for cancer-specific risk prediction. Further large cohort studies aiming to investigate, validate, and optimize the use of circulating miRNA signatures for cancer risk assessment are warranted.

Assessment of salivary miRNA, clinical, and demographic characterization in colorectal cancer diagnosis

AIM

Colorectal cancer (CRC), as the third most frequent malignancy in the world, is the fourth major cause of cancer-related mortality. Its early detection contributes significantly to a reduction in mortality. The objective of this case-control research was to analyze the salivary expression of microRNA-29a (miR-29a) and microRNA-92a (miR-92a), and also to consider demographic, clinical, and nutritional habits for differentiation between CRC patients and healthy controls, especially in the early stages.

METHOD

A standard checklist was used to obtain the demographic information, clinical features, and dietary habits of the case and control groups. Samplings of whole unstimulated saliva samples were obtained from 33 healthy persons and 42 CRC patients. Through real-time PCR, statistical analyses, and machine learning analyses, miR-29a and miR-92a salivary expression levels were evaluated.

RESULTS

The mean salivary expression of miR-92a and miR-29a in CRC patients was significantly higher than in healthy controls (p < 0.001). The area under the receiver operating characteristic curve for miR-92a and miR-29a salivary biomarkers was 0.947 and 0.978, respectively. The sensitivity and specificity values for miR-92a were 95.24 % and 84.85 %, respectively, whereas sensitivity and specificity for miR-29a were equal to 95.20 % and 87.88 %, respectively. Multiple logistic regressions considering demographics, clinical features, and nutritional habits led to values of 95.35 % and 96.88 % as sensitivity and specificity, respectively, and machine learning analysis led to values of 88.89 % and 86.67 % as sensitivity and specificity, respectively.

CONCLUSION

CRC could be accurately diagnosed based on miR-92a and miR-29a levels in saliva. Statistical analysis and machine learning might develop cost-effective models for the distinction of CRC using a noninvasive technique.

Genomic and Transcriptomic Research in the Discovery and Application of Colorectal Cancer Circulating Markers

Colorectal cancer (CRC) is the most frequently occurring malignancy in the world. However, the mortality from CRC can be reduced through early diagnostics, selection of the most effective treatment, observation of the therapy success, and the earliest possible diagnosis of recurrences. A comprehensive analysis of genetic and epigenetic factors contributing to the CRC development is needed to refine diagnostic, therapeutic, and preventive strategies and to ensure appropriate decision making in managing specific CRC cases. The liquid biopsy approach utilizing circulating markers has demonstrated its good performance as a tool to detect the changes in the molecular pathways associated with various cancers. In this review, we attempted to brief the main tendencies in the development of circulating DNA and RNA-based markers in CRC such as cancer-associated DNA mutations, DNA methylation changes, and non-coding RNA expression shifts. Attention is devoted to the existing circulating nucleic acid-based CRC markers, the possibility of their application in clinical practice today, and their future improvement. Approaches to the discovery and verification of new markers are described, and the existing problems and potential solutions for them are highlighted.

Lynch Syndrome Biopathology and Treatment: The Potential Role of microRNAs in Clinical Practice

Lynch syndrome (LS), also known as Hereditary Non-Polyposis Colorectal Cancer (HNPCC), is an autosomal dominant cancer syndrome which causes about 2-3% of cases of colorectal carcinoma. The development of LS is due to the genetic and epigenetic inactivation of genes involved in the DNA mismatch repair (MMR) system, causing an epiphenomenon known as microsatellite instability (MSI). Despite the fact that the genetics of the vast majority of MSI-positive (MSI+) cancers can be explained, the etiology of this specific subset is still poorly understood. As a possible new mechanism, it has been recently demonstrated that the overexpression of certain microRNAs (miRNAs, miRs), such as miR-155, miR-21, miR-137, can induce MSI or modulate the expression of the genes involved in LS pathogenesis. MiRNAs are small RNA molecules that regulate gene expression at the post-transcriptional level by playing a critical role in the modulation of key oncogenic pathways. Increasing evidence of the link between MSI and miRNAs in LS prompted a deeper investigation into the miRNome involved in these diseases. In this regard, in this study, we discuss the emerging role of miRNAs as crucial players in the onset and progression of LS as well as their potential use as disease biomarkers and therapeutic targets in the current view of precision medicine.

Baseline Expression of Exosomal miR-92a-3p and miR-221-3p Could Predict the Response to First-Line Chemotherapy and Survival in Metastatic Colorectal Cancer

The status of predictive biomarkers in metastatic colorectal cancer is currently underdeveloped. Our study aimed to investigate the predictive value of six circulating exosomal miRNAs derived from plasma (miR-92a-3p, miR-143-3p, miR-146a-5p, miR-221-3p, miR-484, and miR-486-5p) for chemosensitivity, resistance patterns, and survival. Thirty-one metastatic colorectal cancer patients were selected before receiving first-line irinotecan- or oxaliplatin-based chemotherapy. Blood samples were harvested at baseline and 4-6 months after the initiation of chemotherapy. The levels of exosomal expression for each miRNA were analyzed by qPCR. Our results for patients receiving first-line FOLFOX showed significantly higher baseline levels of miR-92a-3p (p = 0.007 **), miR-146a-5p (p = 0.036 *), miR-221-3p (p = 0.047 *), and miR-484 (p = 0.009 **) in non-responders (NR) vs. responders (R). Of these, miR-92a-3p (AUC = 0.735), miR-221-3p (AUC = 0.774), and miR-484 (AUC = 0.725) demonstrated a predictive ability to discriminate responses from non-responses, regardless of the therapy used. Moreover, Cox regression analysis indicated that higher expression levels of miR-92a-3p (p = 0.008 **), miR-143-3p (p = 0.009 **), miR-221-3p (p = 0.016 *), and miR-486-5p (p = 0.019 *) at baseline were associated with worse overall survival, while patients expressing higher baseline miR-92a-3p (p = 0.003 **) and miR-486-5p (p = 0.003 **) had lower rates of progression-free survival. No predictive values for candidate microRNAs were found for the post-chemotherapy period. In line with these findings, we conclude that the increased baseline exosomal expression of miR-92a-3p and miR-221-3p seems to predict a lack of response to chemotherapy and lower OS. However, further prospective studies on more patients are needed before drawing practice-changing conclusions.

miR‑519d‑3p released by human blastocysts negatively regulates endometrial epithelial cell adhesion by targeting HIF1α

Successful embryo implantation requires a competent embryo, a receptive endometrium and synchronized communication between them. The selection of embryos with the highest implantation potential remains a challenge in the field of assisted reproductive technology. Moreover, little is known about the precise molecular mechanisms underlying embryo‑endometrium crosstalk. MicroRNAs (miRNAs/miRs) have been detected in the spent embryo culture medium (SCM); however, their functions at the preimplantation stage remain unclear. In the present study, human SCM samples were collected during in vitro fertilization/intracytoplasmic sperm injection‑embryo transfer and divided into implanted and not‑implanted groups according to the clinical pregnancy outcomes. Total RNA was extracted and six miRNAs (miR‑372‑3p, miR‑373‑3p, miR‑516b‑5p, miR‑517a‑3p, miR‑519d‑3p and miR‑520a‑3p) were selected for reverse transcription‑quantitative PCR (RT‑qPCR) analysis. The results revealed that miR‑372‑3p and miR‑519d‑3p were markedly increased in SCM from blastocysts that failed to implant compared with in blastocysts that implanted. The receiver operating characteristic curve analysis revealed that miR‑519d‑3p was superior to miR‑372‑3p in predicting pregnancy outcomes. In vitro miRNA uptake and cell adhesion assays were performed to determine whether miR‑519d‑3p could be taken up by endometrial epithelial cells and to examine the biological roles of miR‑519d‑3p after internalization. Potential targets of miR‑519d‑3p were verified using a dual‑luciferase reporter system. The results demonstrated that miR‑519d‑3p was taken up by human endometrial epithelial cells and that it may inhibit embryo adhesion by targeting HIF1α. Using RT‑qPCR, western blot analysis and flow cytometry assay, HIF1α was shown to inhibit the biosynthesis of fucosyltransferase 7 and sialyl‑Lewis X (sLe^x), a cell‑surface oligosaccharide that serves an important role in embryonic apposition and adhesion. In addition, a mouse model was established and the results suggested that miR‑519d‑3p overexpression hampered embryo implantation in vivo. Taken together, miRNAs in SCM may serve as novel biomarkers for embryo quality. Furthermore, miR‑519d‑3p was shown to mediate embryo‑endometrium crosstalk and to negatively regulate embryo implantation by targeting HIF1α/FUT7/sLe^x pathway.

Dynamic liquid biopsy components as predictive and prognostic biomarkers in colorectal cancer

Colorectal cancer (CRC) is one of the most common cancers worldwide. The diagnosis, prognosis and therapeutic monitoring of CRC depends largely on tissue biopsy. However, due to tumor heterogeneity and limitations such as invasiveness, high cost and limited applicability in longitudinal monitoring, liquid biopsy has gathered immense attention in CRC. Liquid biopsy has several advantages over tissue biopsy including ease of sampling, effective monitoring, and longitudinal assessment of treatment dynamics. Furthermore, the importance of liquid biopsy is signified by approval of several liquid biopsy assays by regulatory bodies indicating the powerful approach of liquid biopsy for comprehensive CRC screening, diagnostic and prognostics. Several liquid biopsy biomarkers such as novel components of the microbiome, non-coding RNAs, extracellular vesicles and circulating tumor DNA are extensively being researched for their role in CRC management. Majority of these components have shown promising results on their clinical application in CRC including early detection, observe tumor heterogeneity for treatment and response, prediction of metastases and relapse and detection of minimal residual disease. Therefore, in this review, we aim to provide updated information on various novel liquid biopsy markers such as a) oral microbiota related bacterial network b) gut microbiome-associated serum metabolites c) PIWI-interacting RNAs (piRNAs), microRNA(miRNAs), Long non-coding RNAs (lncRNAs), circular RNAs (circRNAs) and d) circulating tumor DNAs (ctDNA) and circulating tumor cells (CTC) for their role in disease diagnosis, prognosis, treatment monitoring and their applicability for personalized management of CRC.

miRNAs in Cancer (Review of Literature)

MicroRNAs (miRNAs) are short, noncoding, single-stranded RNA molecules that regulate gene expression at the post-transcriptional level by binding to mRNAs. miRNAs affect the course of processes of fundamental importance for the proper functioning of the organism. These processes include cell division, proliferation, differentiation, cell apoptosis and the formation of blood vessels. Altered expression of individual miRNAs has been shown in numerous cancers, which may indicate the oncogenic or suppressor potential of the molecules in question. This paper discusses the current knowledge about the possibility of using miRNA as a diagnostic marker and a potential target in modern anticancer therapies.

miR-92a promotes cervical cancer cell proliferation, invasion, and migration by directly targeting PIK3R1

OBJECTIVE

To clarify the role of miR-92a in regulating the malignant progression of cervical cancer and its specific molecular mechanism.

METHODS

qRT-PCR was used to detect the differential expression of miR-92a in cervical cancer and adjacent tissues. The effects of overexpression of miR-92a on the proliferation, migration, and invasion of HeLa and SiHa cells were tested. Luciferase assays and rescue experiments were used to investigate the regulatory mechanism of miR-92a on its downstream gene PIK3R1 and their interaction in the progression of cervical cancer.

RESULTS

miR-92a was significantly up-regulated in cervical cancer tissues. Overexpression of miR-92a significantly increased the ability of cervical cancer cells to proliferate, migrate, and invade. PIK3R1 was identified as a downstream gene of miR-92a. In cervical cancer tissues, PIK3R1 was found to be down-regulated and negatively correlated with the level of miR-92a. Overexpression of PIK3R1 reversed the promotional effect of overexpressed miR-92a on the proliferation, migration, and invasion of cervical cancer.

CONCLUSION

miR-92a is up-regulated in cervical cancer tissues. miR-92a promotes the malignant development of cervical cancer by negatively regulating PIK3R1.