Emerging roles of microRNAs in cancer

Discovery and therapeutic exploitation of Master Regulatory miRNAs in Glioblastoma

Glioblastoma is a fatal primary malignant brain tumor. Despite therapies involving surgical resection, chemotherapy, and radiation therapy, the average survival for glioblastoma patients remains at approximately 15 months. MicroRNAs (miRNAs) are short noncoding RNA molecules that regulate the expression of the majority of human genes. Numerous genes are concurrently deregulated in glioblastoma. Consequently, molecular monotherapies have failed to achieve improvements in clinical outcomes. Several lines of evidence suggest that simultaneous targeting of several deregulated molecules is required to achieve better therapies. However, the simultaneous targeting of several deregulated oncogenic drivers is severely limited by the fact that the drugs needed to target many deregulated molecules do not currently exist, and because combining several drugs in a clinical setting leads to an exponential increase in toxicity. We hypothesized that we can develop and use miRNA to simultaneously inhibit multiple deregulated genes for more efficacious glioblastoma therapies. The goal of this study was therefore to identify master regulatory microRNAs (miRNAs) and use them to simultaneously target multiple deregulated molecules for GBM therapy. We defined master regulatory miRNAs as those that target several deregulated genes in glioblastoma. To find master regulatory miRNAs, we first used PAR-CLIP screenings to identify all targets of all miRNAs in glioblastoma cells. We then analyzed TCGA tumor data to determine which of these targets are deregulated in human tumors. We developed and used an algorithm to rank these targets for significance in glioblastoma malignancy based on their magnitude of deregulation, frequency of deregulation, and correlation with patient survival. We then ranked the miRNAs for their capacity of targeting multiple glioblastoma-deregulated genes and therefore the potential to exhibit strong anti-tumor effects when delivered as therapy. Using this strategy, we selected two tumor suppressor master regulatory miRNAs, miR-340, miR-382 and an oncogenic master regulatory miRNA, miR-17. We validated the target genes of the miRNAs and showed that they form part of important glioblastoma regulatory pathways. We then showed that the miRNAs (miR-340 and miR-582) or the miR-17 inhibitor have strong inhibitory effects on glioblastoma cell growth, survival, invasion, stemness and in vivo tumor growth. Ultimately, we developed and successfully tested a new therapeutic approach to delivery miR-340 using MRI guided focused ultrasound and microbubbles (FUS-MB) and special brain penetrating nanoparticles (BPN). This approach resulted in a substantial reduction in tumor volume and prolongation of the survival of glioblastoma-bearing mice and can be translated into clinical trials. We therefore developed and successfully tested a novel strategy to discover and deliver miRNAs for glioblastoma and cancer therapy.

One Sentence Summary

We developed and used new computational, experimental, and therapeutic approaches to identify and therapeutically deliver master regulatory miRNAs to inhibit the growth of glioblastoma, the most common and deadly primary brain tumor.

Linking microRNA to metabolic reprogramming and gut microbiota in the pathogenesis of colorectal cancer (Review)

Colorectal cancer (CRC), an emerging public health concern, is one of the leading causes of cancer morbidity and mortality worldwide. An increasing body of evidence shows that dysfunction in metabolic reprogramming is a crucial characteristic of CRC progression. Specifically, metabolic reprogramming abnormalities in glucose, glutamine and lipid metabolism provide the tumour with energy and nutrients to support its rapid cell proliferation and survival. More recently, microRNAs (miRNAs) appear to be involved in the pathogenesis of CRC, including regulatory roles in energy metabolism. In addition, it has been revealed that dysbiosis in CRC might play a key role in impairing the host metabolic reprogramming processes, and while the exact interactions remain unclear, the link may lie with miRNAs. Hence, the aims of the current review include first, to delineate the metabolic reprogramming abnormalities in CRC; second, to explain how miRNAs mediate the aberrant regulations of CRC metabolic pathways; third, linking miRNAs with metabolic abnormalities and dysbiosis in CRC and finally, to discuss the roles of miRNAs as potential biomarkers.

Liquid biopsy for CNS lymphoma: CSF exosomes and CSF exosomal miR-15a, miR-21, miR-155, miR-210, and miR-19b are promising biomarkers for diagnosis

BACKGROUND

Central nervous system lymphoma (CNSL) is a devastating disease with a poor prognosis. Early diagnosis, monitoring of the treatment response, and outcome prediction carry the utmost importance in the management of patients with CNSL. Surgical biopsy is the gold standard for tissue diagnosis, however, this procedure has potential complications. Therefore, there is a need for a method that provides information about diagnosis and patient monitoring to avoid surgical risks. The study aimed to investigate potential diagnostic biomarkers for patients with CNSL.

METHODS AND RESULTS

Patients with secondary CNSL were included in this study. Serum and cerebrospinal fluid (CSF) samples were collected before treatment and after completion of the treatment. Cell-free DNA (cfDNA), exosomes, free and exosomal microRNA (miR)-15a, miR-21, miR-155, miR-210, and miR-19b in both serum and CSF were examined, and they were compared with the controls. Also, their levels before and after treatment were compared. Nine patients with the diagnosis of secondary CNSL were reviewed. cfDNA, miR-15a, and miR-155 in serum, and exosome in CSF were found to be significantly higher in CNSL patients compared to the controls. Exosomal miR-15a, miR-21, miR-155, miR-210, and miR-19b in CSF were found to be significantly higher in CNSL patients compared to controls, whereas their levels in serum were not significantly high.

CONCLUSIONS

Our findings suggested that exosomes and exosomal miR-15a, miR-21, miR-155, miR-210 and miR-19b in CSF would be promising biomarkers for the diagnosis of patients with CNSL. Further studies are needed to confirm our findings.

Up-Regulation of miR-625-5p Correlates with Suppressed Sox2, Increased Apoptosis, and Cell Cycle Arrest via The PI3K/AKT Signalling Pathway in Acute Myeloid Leukaemia

Background: Up-regulation of the microRNA-625 and abnormal expression of the Sox2 gene have been studied and seen in several tumors. Few reports have also shown the aberrant expression of miR-625 and Sox2 expression in various cancers. Several studies have also confirmed that phosphatidylinositol 3' -kinase /protein kinase B pathways regulate hematological malignancies, including Acute Myeloid Leukemia (AML). Thus, this study aimed to investigate the effects of mir-625 up-regulation on proliferation, apoptosis, and cell cycle by targeting the Sox2 gene via the downstream Akt signaling pathway and cell cycle regulators, such as p21, p27, and cyclin E in the KG-1 cell line. Materials and Methods: Cells obtained from the KG-1 cell line were cultured and transfected with plasmid DNA (miR-625) and scrambled as the control using the Lonza electroporation system. Flow cytometry was used to evaluate cell cycle, proliferation, and apoptosis. Relative gene expression was validated by qRT-PCR. All data were analyzed using graph pad prism 7.01 and REST 2009. Results: KG-1 cells transfected with the mir625-GFP construct showed decreased proliferation, increased apoptosis, and induced cell cycle arrest. Low levels of Sox2, p21, cyclin E, and up-regulation of p27 were confirmed and validated by qRT-PCR ( P < 0.05 ). Conclusion: MiR-625 can be a promising approach to aid in the treatment of AML. However, further studies are required in this field.

MicroRNAs role in telomere length maintenance and telomerase activity in tumor cells

MiRNAs, a class of non-coding RNA molecules, have emerged as critical modulators of telomere length and telomerase activity by finely tuning the expression of target genes (and not gene targets) within signaling pathways involved in telomere homeostasis. The primary objective of this systematic review was to compile and synthesize the existing body of knowledge on the role, association, and involvement of miRNAs in telomere length. Additionally, the review explored the regulation, function, and activation mechanism of the human telomerase reverse transcriptase (hTERT) gene and telomerase activity in tumor cells. A comprehensive analysis of 47 selected articles revealed 40 distinct miRNAs involved in these processes. These miRNAs were shown to exert their function, in both clinical cases and cell line models, either directly or indirectly, regulating hTERT and telomerase activity through distinct molecular mechanisms. The regulatory roles of these miRNAs significantly affected major cancer phenotypes, with outcomes largely dependent on the tissue type and the cellular actions within the tumor cells, whereby they functioned as oncogenes or tumor suppressors. These findings strongly support the pivotal role of miRNAs in modulating telomere length and telomerase activity, thereby contributing to the intricate and complex regulation of telomere homeostasis in tumor cells. Moreover, they emphasize the potential of targeting miRNAs and key regulatory genes as therapeutic strategies to disrupt cancer cell growth and promote senescence, offering promising avenues for novel cancer treatments.

Long noncoding RNA VPS9D1-AS1 promotes the progression of endometrial cancer via regulation of the miR-187-3p/S100A4 axis

VPS9D1-AS1 functions as an oncogene in many cancers. However, its role and potential mechanism in the progression of endometrial cancer (EC) are not fully understood. VPS9D1-AS1 levels in EC and adjacent normal tissues were investigated using the TCGA-UCEC cohort and 24 paired clinical samples. The roles of VPS9D1-AS1 and miR-187-3p in cell cycle, proliferation, and apoptosis were evaluated by loss- and gain-of-function experiments. In addition, the effect of VPS9D1-AS1 on tumor growth was further investigated in vivo. Rescue experiments were performed to investigate the involvement of the miR-187-3p/S100A4 axis in VPS9D1-AS1 knockdown-mediated antitumor effects. VPS9D1-AS1 was highly expressed in EC tissues. VPS9D1-AS1 knockdown, similar to miR-187-3p overexpression, significantly inhibited cell proliferation, inhibited colony formation, induced cell cycle arrest, and facilitated apoptosis of KLE cells. MiR-187-3p bound directly to VPS9D1-AS1 and the 3'UTR of S100A4. Furthermore, VPS9D1-AS1 negatively regulated miR-187-3p while positively regulating S100A4 expression in EC cells. MiR-187-3p knockdown or S100A4 overexpression partially reversed the tumor suppressive function of VPS9D1-AS1 knockdown. The results suggest that VPS9D1-AS1 affects EC progression by regulating the miR-187-3p/S100A4 axis. This may provide a promising therapeutic target to help treat EC.

Noncoding RNAs in B cell non-Hodgkins lymphoma

B-cell non-Hodgkins lymphomas (BCNHLs) are a category of B-cell cancers that show heterogeneity. These blood disorders are derived from different levels of B-cell maturity. Among NHL cases, ∼80-90 % are derived from B-cells. Recent studies have demonstrated that noncoding RNAs (ncRNAs) contribute to almost all parts of mechanisms and are essential in tumorigenesis, including B-cell non-Hodgkins lymphomas. The study of ncRNA dysregulations in B-cell lymphoma unravels important mysteries in lymphoma's molecular etiology. It seems also necessary for discovering novel trials as well as investigating the potential of ncRNAs as markers for their diagnosis and prognosis. In the current study, we summarize the role of ncRNAs involving miRNAs, long noncoding RNAs, as well as circular RNAs in the development or progression of BCNHLs.

Structure and Functions of HMGB3 Protein

HMGB3 protein belongs to the group of HMGB proteins from the superfamily of nuclear proteins with high electrophoretic mobility. HMGB proteins play an active part in almost all cellular processes associated with DNA-repair, replication, recombination, and transcription-and, additionally, can act as cytokines during infectious processes, inflammatory responses, and injuries. Although the structure and functions of HMGB1 and HMGB2 proteins have been intensively studied for decades, very little attention has been paid to HMGB3 until recently. In this review, we summarize the currently available data on the molecular structure, post-translational modifications, and biological functions of HMGB3, as well as the possible role of the ubiquitin-proteasome system-dependent HMGB3 degradation in tumor development.

Exploring of miR-155-5p, miR-181b-5p, and miR-454-3p Expressions in Circulating Cell-Free RNA: Insights from Peripheral Blood of Uveal Malignant Melanoma Patients

The identification of novel non-invasive biomarkers is imperative for the early diagnosis and monitoring of malignant melanoma. The objective of this study is to examine the expression levels of miR-155-5p, miR-181b-5p, and miR-454-3p in circulating cell-free RNA obtained from plasma samples of the 72 uveal malignant melanoma patients and to compare these levels with those of 72 healthy controls. The analysis showed that the expression level of the miR-181b-5p has increased 9.25 fold, and expression level of miR-155-5p has increased 6.67 fold, and miR-454-3p expression level has increased 4.14 fold in the patient group compared with the levels in the healthy control group (p = 0.005). It was found that the high expression levels of the three miRNAs were statistically significant in patients compared with in the healthy control group. The statistical evaluations between miRNA expression levels and clinical data showed that miR-155-5p had significant association with radiation therapy (p = 0.040), and miR-454-3p showed a significant association with smoking and alcohol use respectively (p = 0.009, and p = 0.026). The significantly elevated expression levels of miR-181b-5p, miR-155-5p, and miR-454-3p in the circulating cell-free RNA of plasma from uveal melanoma patients, in comparison to those in the healthy control group, suggest the potential usefulness of these biomarkers for both early diagnosis and disease monitoring. However, more extensive and future studies are needed to use these molecules in early diagnosis and disease monitoring.

RAS-RAF-miR-296-3p signaling axis increases Rad18 expression to augment radioresistance in pancreatic and thyroid cancers

Oncogenic RAS and RAF signaling has been implicated in contributing to radioresistance in pancreatic and thyroid cancers. In this study, we sought to better clarify molecular mechanisms contributing to this effect. We discovered that miRNA 296-3p (miR-296-3p) is significantly correlated with radiosensitivity in a panel of pancreatic cancer cells, and miR-296-3p is highly expressed in normal cells, but low in cancer cell lines. Elevated expression of miR-296-3p increases radiosensitization while decreasing the expression of the DNA repair enzyme RAD18 in both pancreatic and thyroid cancer cells. RAD18 is overexpressed in both pancreatic and thyroid tumors compared to matched normal controls, and high expression of RAD18 in tumors is associated with poor prognostic features. Modulating the expression of mutant KRAS in pancreatic cancer cells or mutant BRAF in thyroid cancer cells demonstrates a tight regulation of RAD18 expression in both cancer types. Depletion of RAD18 results in DNA damage and radiation-induced cell death. Importantly, RAD18 depletion in combination with radiotherapy results in marked and sustained tumor regression in KRAS mutant pancreatic cancer orthotopic tumors and BRAF mutant thyroid heterotopic tumors. Overall, our findings identify a novel coordinated RAS/RAF-miR-296-3p-RAD18 signaling network in pancreatic and thyroid cancer cells, which leads to enhanced radioresistance.

The Analysis of Selected miRNAs and Target MDM2 Gene Expression in Oral Squamous Cell Carcinoma

MiRNAs could play an important role in tumorigenesis and progression. The oncoprotein MDM2 (murine double minute 2) was identified as a negative regulator of the tumour suppressor p53. This study aims to analyse the expression of the MDM2 target miRNA candidates (miR-3613-3p, miR-371b-5p and miR-3658) and the MDM2 gene in oral squamous cell carcinoma tumour and margin samples and their association with the selected socio-demographic and clinicopathological characteristics. The study group consisted of 50 patients. The miRNAs and MDM2 gene expression levels were assessed by qPCR. The expression analysis of the miRNAs showed the expression of only one of them, i.e., miR-3613-3p. We found no statistically significant differences in the miR-3613-3p expression in tumour samples compared to the margin samples. When analysing the effect of smoking on miR-3613-3p expression, we demonstrated a statistically significant difference between smokers and non-smokers. In addition, we showed an association between the miR-3613-3p expression level and some clinical parameters in tumour samples (T, N and G). Our study demonstrates that miR-3613-3p overexpression is involved in the tumour progression of OSCC. This indicates that miR-3613-3p possesses potential prognostic values.

Construct ceRNA Network and Risk Model of Breast Cancer Using Machine Learning Methods under the Mechanism of Cuproptosis

Breast cancer (BRCA) has an undesirable prognosis and is the second most common cancer among women after lung cancer. A novel mechanism of programmed cell death called cuproptosis is linked to the development and spread of tumor cells. However, the function of cuproptosis in BRCA remains unknown. To this date, no studies have used machine learning methods to screen for characteristic genes to explore the role of cuproptosis-related genes (CRGs) in breast cancer. Therefore, 14 cuproptosis-related characteristic genes (CRCGs) were discovered by the feature selection of 39 differentially expressed CRGs using the three machine learning methods LASSO, SVM-RFE, and random forest. Through the PPI network and immune infiltration analysis, we found that PRNP was the key CRCG. The miRTarBase, TargetScan, and miRDB databases were then used to identify hsa-miR-192-5p and hsa-miR-215-5p as the upstream miRNA of PRNP, and the upstream lncRNA, CARMN, was identified by the StarBase database. Thus, the mRNA PRNP/miRNA hsa-miR-192-5p and hsa-miR-215-5p/lncRNA CARMN ceRNA network was constructed. This ceRNA network, which has not been studied before, is extremely innovative. Furthermore, four cuproptosis-related lncRNAs (CRLs) were screened in TCGA-BRCA by univariate Cox, LASSO, and multivariate Cox regression analysis. The risk model was constructed by using these four CRLs, and the risk score = C9orf163 * (1.8365) + PHC2-AS1 * (-2.2985) + AC087741.1 * (-0.9504) + AL109824.1 * (0.6016). The ROC curve and C-index demonstrated the superior predictive capacity of the risk model, and the ROC curve demonstrated that the AUC of 1-, 3-, and 5-year OS in all samples was 0.721, 0.695, and 0.633, respectively. Finally, 50 prospective sensitive medicines were screened with the pRRophetic R package, among which 17-AAG may be a therapeutic agent for high-risk patients, while the other 49 medicines may be suitable for the treatment of low-risk patients. In conclusion, our study constructs a new ceRNA network and a novel risk model, which offer a theoretical foundation for the treatment of BRCA and will aid in improving the prognosis of BRCA.

Circulating miRNA as a Biomarker in Oral Cancer Liquid Biopsy

Oral cancer is currently challenging the healthcare system, with a high incidence among the population and a poor survival rate. One of the main focuses related to this malignancy is the urge to implement a viable approach for improving its early diagnosis. By introducing the use of liquid biopsy and the identification of potential biomarkers, aiming for a noninvasive approach, new advancements offer promising perspectives in the diagnosis of oral cancer. The present review discusses the potential of circulating miRNAs as oral cancer biomarkers identified in body fluids such as serum, plasma, and saliva samples of oral cancer patients. Existing results reveal an important implication of different miRNA expressions involved in the initiation, development, progression, and metastasis rate of oral malignancy. Liquid biomarkers can play a crucial role in the development of the concept of personalized medicine, providing a wide range of clinical applications and future targeted therapies.

Circulating tumor nucleic acids: biology, release mechanisms, and clinical relevance

BACKGROUND

Despite advances in early detection and therapies, cancer is still one of the most common causes of death worldwide. Since each tumor is unique, there is a need to implement personalized care and develop robust tools for monitoring treatment response to assess drug efficacy and prevent disease relapse.

MAIN BODY

Recent developments in liquid biopsies have enabled real-time noninvasive monitoring of tumor burden through the detection of molecules shed by tumors in the blood. These molecules include circulating tumor nucleic acids (ctNAs), comprising cell-free DNA or RNA molecules passively and/or actively released from tumor cells. Often highlighted for their diagnostic, predictive, and prognostic potential, these biomarkers possess valuable information about tumor characteristics and evolution. While circulating tumor DNA (ctDNA) has been in the spotlight for the last decade, less is known about circulating tumor RNA (ctRNA). There are unanswered questions about why some tumors shed high amounts of ctNAs while others have undetectable levels. Also, there are gaps in our understanding of associations between tumor evolution and ctNA characteristics and shedding kinetics. In this review, we summarize current knowledge about ctNA biology and release mechanisms and put this information into the context of tumor evolution and clinical utility.

CONCLUSIONS

A deeper understanding of the biology of ctDNA and ctRNA may inform the use of liquid biopsies in personalized medicine to improve cancer patient outcomes.

Overview of Computational and Experimental Methods to Identify Tissue-Specific MicroRNA Targets

As ubiquitous posttranscriptional regulators of gene expression, microRNAs (miRNAs) play key roles in cell physiology and function across taxa. In the last two decades, we have gained a good understanding about miRNA biogenesis pathways, modes of action, and consequences of miRNA-mediated gene regulation. More recently, research has focused on exploring causes for miRNA dysregulation, miRNA-mediated crosstalk between genes and signaling pathways, and the role of miRNAs in disease.This chapter discusses methods for the identification of miRNA-target interactions and causes for tissue-specific miRNA-target regulation. Computational approaches for predicting miRNA target sites and assessing tissue-specific target regulation are discussed. Moreover, there is an emphasis on features that affect miRNA target recognition and how high-throughput sequencing protocols can help in assessing miRNA-mediated gene regulation on a genome-wide scale. In addition, this chapter introduces some experimental approaches for the validation of miRNA targets as well as web-based resources sharing predicted and validated miRNA-target interactions.

MicroRNAs in esophageal squamous cell carcinoma: Application in prognosis, diagnosis, and drug delivery

MicroRNAs (miRNAs) play a vital role in various cell biology processes, including cancer formation. These small non-coding RNAs could function as diagnostic and prognostic markers. They may involve esophageal squamous cell carcinoma (ESCC) and distinctive miRNA expression profiles; they are also known as therapeutic targets in human diseases. Therefore, in this study, the function of miRNAs was reviewed regarding the prognosis and diagnosis of ESCC. The changes in miRNAs before and after cancer therapy and the effects of miRNAs on chemo-susceptibility patterns were also investigated. MiRNA delivery systems in ESCC were also highlighted, providing a perspective on how these systems can improve miRNA efficiency.

Crosstalk between Tumor-Associated Macrophages and MicroRNAs: A Key Role in Tumor Microenvironment

As an in-depth understanding of immunotherapy continues to grow, current anticancer therapy research is increasingly focused on the tumor microenvironment (TME). MicroRNAs (miRNAs) play crucial roles in the regulation of genetic information and expression and mediate interactions between tumor cells and components in the TME, such as tumor-associated macrophages (macrophages). Macrophages are abundant in the TME, and their different polarization directions can promote or inhibit tumor growth and progression. By regulating biological behaviors, such as macrophage recruitment, infiltration, and polarization, miRNAs can affect various molecular pathways to regulate tumor progression and treatment response. In this review, we discuss in detail the effects of macrophages on tumors and the multifaceted effects of miRNAs on macrophages. We also discuss the potential clinical applications and prospects of targeted therapy based on miRNAs, novel clinical biomarkers, and drug delivery systems.

The role of macrophage subtypes and exosomes in immunomodulation

Macrophages are influential members of the innate immune system that can be reversibly polarized by different microenvironment signals. Cell polarization leads to a wide range of features, involving the migration, development, and organization of the cells. There is mounting evidence that macrophage polarization plays a key role in the initiation and development of a wide range of diseases. This study aims to give an overview of macrophage polarization, their different subtypes, and the importance of alternatively activated M2 macrophage and classically activated M1 macrophage in immune responses and pathological conditions. This review provides insight on the role of exosomes in M1/M2-like macrophage polarization and their potential as a promising therapeutic candidate.

OncomiRs as noncoding RNAs having functions in cancer: Their role in immune suppression and clinical implications

Currently, microRNAs have been established as central players in tumorigenesis, but above all, they have opened an important door for our understanding of immune and tumor cell communication. This dialog is largely due to onco-miR transfer from tumor cells to cells of the tumor microenvironment by exosome. This review outlines recent advances regarding the role of oncomiRs in enhancing cancer and how they modulate the cancer-related immune response in the tumor immune microenvironment.

MicroRNAs (miRNAs) are a type of noncoding RNA that are important posttranscriptional regulators of messenger RNA (mRNA) translation into proteins. By regulating gene expression, miRNAs enhance or inhibit cancer development and participate in several cancer biological processes, including proliferation, invasion metastasis, angiogenesis, chemoresistance and immune escape. Consistent with their widespread effects, miRNAs have been categorized as oncogenes (oncomiRs) or tumor suppressor (TS) miRNAs. MiRNAs that promote tumor growth, called oncomiRs, inhibit messenger RNAs of TS genes and are therefore overexpressed in cancer. In contrast, TS miRNAs inhibit oncogene messenger RNAs and are therefore underexpressed in cancer. Endogenous miRNAs regulate different cellular pathways in all cell types. Therefore, they are not only key modulators in cancer cells but also in the cells constituting their microenvironments. Recently, it was shown that miRNAs are also involved in intercellular communication. Indeed, miRNAs can be transferred from one cell type to another where they regulate targeted gene expression. The primary carriers for the transfer of miRNAs from one cell to another are exosomes. Exosomes are currently considered the primary carriers for communication between the tumor and its surrounding stromal cells to support cancer progression and drive immune suppression. Exosome and miRNAs are seen by many as a hope for developing a new class of targeted therapy. This review outlines recent advances in understanding the role of oncomiRs in enhancing cancer and how they promote its aggressive characteristics and deeply discusses the role of oncomiRs in suppressing the anticancer immune response in its microenvironment. Additionally, further understanding the mechanism of oncomiR-related immune suppression will facilitate the use of miRNAs as biomarkers for impaired antitumor immune function, making them ideal immunotherapy targets.

Contributions of Circulating microRNAs for Early Detection of Lung Cancer

There is unmet need to develop circulating biomarkers that would enable earlier interception of lung cancer when more effective treatment options are available. Here, a set of 30 miRNAs, selected from a review of the published literature were assessed for their predictive performance in identifying lung cancer cases in the pre-diagnostic setting. The 30 miRNAs were assayed using sera collected from 102 individuals diagnosed with lung cancer within one year following blood draw and 212 controls matched for age, sex, and smoking status. The additive performance of top-performing miRNA candidates in combination with a previously validated four-protein marker panel (4MP) consisting of the precursor form of surfactant protein B (Pro-SFTPB), cancer antigen 125 (CA125), carcinoembryonic antigen (CEA) and cytokeratin-19 fragment (CYFRA21-1) was additionally assessed. Of the 30 miRNAs evaluated, five (miR-320a-3p, miR-210-3p, miR-92a-3p, miR-21-5p, and miR-140-3p) were statistically significantly (Wilcoxon rank sum test p < 0.05) elevated in case sera compared to controls, with individual AUCs ranging from 0.57−0.62. Compared to the 4MP alone, the combination of 3-miRNAs + 4MP improved sensitivity at 95% specificity by 19.1% ((95% CI of difference 0.0−28.6); two-sided p: 0.006). Our findings demonstrate utility for miRNAs for early detection of lung cancer in combination with a four-protein marker panel.

Liquid Biopsy and Circulating Biomarkers for the Diagnosis of Precancerous and Cancerous Oral Lesions

Oral cancer is one of the most common malignancies worldwide, accounting for 2% of all cases annually and 1.8% of all cancer deaths. To date, tissue biopsy and histopathological analyses are the gold standard methods for the diagnosis of oral cancers. However, oral cancer is generally diagnosed at advanced stages with a consequent poor 5-year survival (~50%) due to limited screening programs and inefficient physical examination strategies. To address these limitations, liquid biopsy is recently emerging as a novel minimally invasive tool for the early identification of tumors as well as for the evaluation of tumor heterogeneity and prognosis of patients. Several studies have demonstrated that liquid biopsy in oral cancer could be useful for the detection of circulating biomarkers including circulating tumor DNA (ctDNA), microRNAs (miRNAs), proteins, and exosomes, thus improving diagnostic strategies and paving the way to personalized medicine. However, the application of liquid biopsy in oral cancer is still limited and further studies are needed to better clarify its clinical impact. The present manuscript aims to provide an updated overview of the potential use of liquid biopsy as an additional tool for the management of oral lesions by describing the available methodologies and the most promising biomarkers.

Lower expression of KAI1 as a biomarker of poor survival prognosis of melanoma combined with colorectal cancer metastasis

Objective

This study aimed to investigate the correlation between KAI1 (CD82) and miR-633 expression and prognosis and survival time of patients with melanoma combined with colorectal cancer (CRC).

Methods

Clinical and follow-up data of melanoma and CRC patients were recorded, and the expression levels of KAI1 and miR-633 were detected. Pearson chi-square tests and Spearman correlation coefficient were used to analyze the relationship between prognosis and related parameters in these patients. Cox proportional risk regression and receiver operating characteristic curve analyses were used.

Results

Overall, 195 patients were included. KAI1 and miR-633 expression levels were significantly correlated with the prognosis of patients with melanoma combined with CRC. Spearman correlation analysis showed that the expression levels of KAI1 and miR-633 were significantly correlated with the prognosis of patients. Multivariate Cox regression analysis suggested that low expression levels of KAI1 and high expression levels of miR-633 indicated shorter survival time for patients.

Conclusions

KAI1 expression was significantly correlated with melanoma and CRC patient prognosis. When KAI1 expression levels were low, the patient survival time was poor.

Exosome-transmitted miR-3124-5p promotes cholangiocarcinoma development via targeting GDF11

Objective

Cholangiocarcinoma (CHOL) is a deadly cancer worldwide with limited available therapies. The aim of this study was to investigate key exosomal miRNAs and their functions in CHOL development.

Methods

Serum exosomes were isolated from patients with CHOL and healthy controls, followed by miRNA sequencing for identifying differentially expressed miRNAs (DEMs) and their functions. Then, the expression of key DEMs was experimentally validated in exosomes from clinical CHOL patients and CHOL cells. The effects of overexpression of key DEMs on CHOL cell migration and proliferation were investigated. A key exosomal DEM miR-3124-5p was identified. The effects of overexpression or knockdown of exosomal miR-3124-5p on the proliferation, migration, and angiogenesis of human umbilical vein endothelial cells (HUVECs) were investigated. Moreover, the function of exosomal miR-3124-5p on tumor growth in vivo was explored.

Results

A total of 632 exosomal DEMs were identified between CHOL and control samples. Target genes of DEMs were significantly enriched in pathways, such as the p53 signaling pathway. miR-3124-5p was upregulated in serum exosomes from CHOL patients and exosomes from CHOL cells, and overexpression of miR-3124-5p promoted RBE cell migration and viability. Moreover, overexpression of exosomal miR-3124-5p promoted the proliferation, migration, and angiogenesis of HUVECs, while knockdown of miR-3124-5p had the opposite effect. miR-3124-5p could target growth differentiation factor 11 (GDF11) and downregulate GDF11 expression. Furthermore, exosomal miR-3124-5p promoted tumor growth in vivo.

Conclusions

Our findings revealed that exosome-encapsulated miR-3124-5p promoted the malignant progression of CHOL by targeting GDF11. Exosomal miR-3124-5p and GDF11 could be promising biomarkers or therapeutic targets for CHOL.

Review: New horizons in retinoblastoma treatment: an updated review article

Retinoblastoma (Rb) is a rare childhood intraocular malignancy with an incidence rate of approximately 9000 children per year worldwide. The management of Rb is inherently complex and depends on several factors. The orders of priorities in the treatment of Rb are saving life, globe salvage and vision salvage. Rarity and the young age at diagnosis impede conducting randomized clinical trials (RCTs) for new therapeutic options, and therefore pre-RCTs studies are needed. This review provides an overview of advances in Rb treatment options, focusing on the emergence of new small molecules to treat Rb. Articles related to the management and treatments of Rb were searched in different databases. Several studies and animal models discussing recent advances in the treatment of Rb were included to have a better grasp of the biological mechanisms of Rb. Over the years, the principles of management and treatment of Rb have changed significantly. Innovations in targeted therapies and molecular biology have led to improved patient and ocular survival. However, there is still a need for further evaluation of the long-term effects of these new treatments.

The potential of B7-H6 as a therapeutic target in cancer immunotherapy

Immune checkpoints are vital molecules that regulate T-cell function by activation or inhibition. Among the immune checkpoint molecules, the B7-family proteins are significantly involved in the immune escape of tumor cells. By binding to inhibitory receptors, they can suppress T-cell-mediated immunity. B7-family proteins are found at various stages of tumor microenvironment formation and promote tumorigenesis and tumor progression. B7-H6 (encoded by gene NCR3LG1) is a prominent member of the family. It has unique immunogenic properties and is involved in natural killer (NK) cell immunosurveillance by binding to the NKp30 receptor. High B7-H6 expression in certain tumor types and shortage of or low expression in healthy cells - except in cases of inflammatory or microbial stimulation - have made the protein an attractive target of research activities in recent years. The avoidance of NK-mediated B7-H6 detection is a mechanism through which tumor cells escape immune surveillance. The stimulation of tumorigenesis occurs by suppressing caspase cascade initiation and anti-apoptosis activity stimulation via the STAT3 pathway. The B7-H6-NKp30 complex on the tumor membrane activates the NK cells and releases both tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ). B7-H6 is highly expressed in a wide range of tumor cells, including glioma, hematologic malignant tumors, and breast cancer cells. Clinical examination of cancer patients indicated that the expression of B7-H6 is related to distant metastasis status and permits postoperative prognosis. Because of its unique properties, B7-H6 has a high potential be utilized as a biological marker for cancer diagnosis and prognosis, as well as a target for novel treatment options.

Circulating MicroRNAs as Quantitative Biomarkers for Diagnosis and Prognosis of Uveal Melanoma

For uveal melanoma (UM) patients, it is significant to establish diagnosis and prognosis evaluation systems through imaging techniques. However, imaging examinations are short of quantitative biomarkers and it is difficult to finish early diagnosis of UM. In order to discover new molecular biomarkers for the diagnosis and prognostic evaluation of UM, six circulating miRNAs (mir-132-3p, mir-21-5p, mir-34a-5p, mir-126-3p, mir-199a-3p, mir-214-3p) were chosen as candidates for independent validation. Validation of these miRNAs was performed in a cohort of 20 patients, including 10 spindle-shaped melanoma and 10 epithelioid cell melanoma, and 10 healthy donors. Then 5 patients with metastatic UM were included to validate the performance of miRNAs in advanced UM. Serum levels of miRNAs were determined using quantitative real-time PCR. We confirmed significantly higher levels of three miRNAs in serum of UM patients in comparison to healthy controls, and miR-199a-3p had the best performance (p < 0.0001; AUC = 0.985). MiR-214-3p and miR-21-5p were significantly upregulated in serum of epithelioid cell melanoma patients compared to spindle-shaped melanoma patients and miR-132-3p and, conversely, were significantly downregulated in serum of epithelioid cell melanoma patients. MiR-21-5p shows their best performance (p < 0.0001; AUC = 0.980). Both miR-199a-3p and miR-21-5p showed great performance in advanced UM. Significantly higher levels of miR-21-5p (p < 0.001) were found in serum of metastatic UM patients compared to patients with localized spindle-shaped melanoma, and significantly higher levels of miR-199a-3p (p < 0.001) were detected in serum of metastatic UM patients compared to healthy controls. Our preliminary data indicate promising diagnostic utility of circulating miR-199a-3p and promising prognostic utility of circulating miR-21-5p in both early and advanced UM patients.

Restoration of miR-23a expression by chidamide sensitizes CML cells to imatinib treatment with concomitant downregulation of CRYAB

MicroRNAs (miRNAs) are involved in various processes from the initiation and development of cancers, including chronic myeloid leukemia (CML). In this report, we aimed to investigate the roles of miR-23a in the regulation of imatinib mesylate (IM) sensitivity in CML cells and the possible mechanisms involved in this process. We demonstrated that the expression of miR-23a was markedly low in bone marrow mononuclear cells from patients in whom IM treatment had failed and imatinib-resistant K562/G01 cells when compared to patients with optimal responses and imatinib-sensitive K562 cells, respectively. Overexpression of miR-23a was shown to induce apoptosis of K562/G01 cells and sensitize these cells to imatinib treatment. With the aid of bioinformatics analysis, we revealed that CRYAB could be a potential downstream effector of miR-23a, contributing to miR-23a-mediated IM resistance. We also observed that the expression of CRYAB was inversely correlated with miR-23a expression in CML cell lines and patient samples. Importantly, chidamide upregulated miR-23a expression and reversed the IM resistance of CML cells. Together, these findings strongly suggest that miR-23a acts as a tumor suppressor by downregulating CRYAB expression. Restoration of miR-23a by chidamide may therefore have a therapeutic effect in controlling the sensitivity of CML cells to imatinib.

Interactions between miRNAs and Double-Strand Breaks DNA Repair Genes, Pursuing a Fine-Tuning of Repair

The repair of DNA damage is a crucial process for the correct maintenance of genetic information, thus, allowing the proper functioning of cells. Among the different types of lesions occurring in DNA, double-strand breaks (DSBs) are considered the most harmful type of lesion, which can result in significant loss of genetic information, leading to diseases, such as cancer. DSB repair occurs through two main mechanisms, called non-homologous end joining (NHEJ) and homologous recombination repair (HRR). There is evidence showing that miRNAs play an important role in the regulation of genes acting in NHEJ and HRR mechanisms, either through direct complementary binding to mRNA targets, thus, repressing translation, or by targeting other genes involved in the transcription and activity of DSB repair genes. Therefore, alteration of miRNA expression has an impact on the ability of cells to repair DSBs, which, in turn, affects cancer therapy sensitivity. This latter gives account of the importance of miRNAs as regulators of NHEJ and HRR and places them as a promising target to improve cancer therapy. Here, we review recent reports demonstrating an association between miRNAs and genes involved in NHEJ and HRR. We employed the Web of Science search query TS (“gene official symbol/gene aliases*” AND “miRNA/microRNA/miR-”) and focused on articles published in the last decade, between 2010 and 2021. We also performed a data analysis to represent miRNA–mRNA validated interactions from TarBase v.8, in order to offer an updated overview about the role of miRNAs as regulators of DSB repair.

The role of Exosomal miRNAs in cancer

Exosomal miRNAs have attracted much attention due to their critical role in regulating genes and the altered expression of miRNAs in virtually all cancers affecting humans (Sun et al. in Mol Cancer 17(1):14, 2018). Exosomal miRNAs modulate processes that interfere with cancer immunity and microenvironment, and are significantly involved in tumor growth, invasion, metastasis, angiogenesis and drug resistance. Fully investigating the detailed mechanism of miRNAs in the occurrence and development of various cancers could help not only in the treatment of cancers but also in the prevention of malignant diseases. The current review highlighted recently published advances regarding cancer-derived exosomes, e.g., sorting and delivery mechanisms for RNAs. Exosomal miRNAs that modulate cancer cell-to-cell communication, impacting tumor growth, angiogenesis, metastasis and multiple biological features, were discussed. Finally, the potential role of exosomal miRNAs as diagnostic and prognostic molecular markers was summarized, as well as their usefulness in detecting cancer resistance to therapeutic agents.

Novel approaches in cancer treatment: preclinical and clinical development of small non-coding RNA therapeutics

Short or small interfering RNAs (siRNAs) and microRNA (miRNAs) are molecules similar in size and function able to inhibit gene expression based on their complementarity with mRNA sequences, inducing the degradation of the transcript or the inhibition of their translation.

siRNAs bind specifically to a single gene location by sequence complementarity and regulate gene expression by specifically targeting transcription units via posttranscriptional gene silencing. miRNAs can regulate the expression of different gene targets through their imperfect base pairing.

This process - known as RNA interference (RNAi) - modulates transcription in order to maintain a correct physiological environment, playing a role in almost the totality of the cellular pathways.

siRNAs have been evolutionary evolved for the protection of genome integrity in response to exogenous and invasive nucleic acids such as transgenes or transposons. Artificial siRNAs are widely used in molecular biology for transient silencing of genes of interest. This strategy allows to inhibit the expression of any target protein of known sequence and is currently used for the treatment of different human diseases including cancer.

Modifications and rearrangements in gene regions encoding for miRNAs have been found in cancer cells, and specific miRNA expression profiles characterize the developmental lineage and the differentiation state of the tumor. miRNAs with different expression patterns in tumors have been reported as oncogenes (oncomirs) or tumor-suppressors (anti-oncomirs). RNA modulation has become important in cancer research not only for development of early and easy diagnosis tools but also as a promising novel therapeutic approach.

Despite the emerging discoveries supporting the role of miRNAs in carcinogenesis and their and siRNAs possible use in therapy, a series of concerns regarding their development, delivery and side effects have arisen.

In this review we report the biology of miRNAs and siRNAs in relation to cancer summarizing the recent methods described to use them as novel therapeutic drugs and methods to specifically deliver them to cancer cells and overcome the limitations in the use of these molecules.

Expression of miRNA-601 and PD-L1 among Iranian Patients with Lung Cancer and Their Relationship with Smoking and Mycoplasma Infection

OBJECTIVE

microRNAs (miRNAs) are highly conserved noncoding RNA molecules that mainly function to regulate gene expressions, and have a significant role in tumourigenesis. Programmed cell death-ligand 1 (PD-L1) is a major co-inhibitory checkpoint signal that controls T cell activities, maintains peripheral tolerance and is contribute to the development of cancer. The aim of this study is to examine miRNA-601 and PD-L1 gene expression in patients with non-small-cell lung cancer (NSCLC) and its relation with Mycoplasma infection.

MATERIALS AND METHODS

In this case-control study, respiratory secretions and blood samples were collected from 80 healthy people and 80 NSCLC patients. The expression levels of miRNA-601 and PD-L1 were evaluated using real-time polymerase chain reaction (qRT-PCR). The presence of Mycoplasma species in respiratory secretions was detected by biochemical assays and PCR.

RESULTS

There was no significant difference in the expression level of miRNA-601 between control and patients with tumour stage I, but miRNA-601 expression was significantly downregulated in patients with tumour stages II, III, and IV (P<0.05). A significant, negative relationship was found between miRNA-601 expression and tumour stage (P<0.001). Overexpression of PD-L1 was found in all of the disease stages. PCR results showed the presence of Mycoplasma pneumoniae (M. pneumoniae) in respiratory secretions from patients with stages III and IV NSCLC. We observed that 72% of patients with stages III and IV NSCLC had a positive smoking history and 65.3% were positive for Mycoplasma.

CONCLUSION

Serum miRNA-601 may act as a potential noninvasive biomarker for lung cancer and Mycoplasma infection prognosis.

Antisense oligonucleotides for Alzheimer's disease therapy: from the mRNA to miRNA paradigm

Alzheimer's disease (AD) represents a particular therapeutic challenge because its aetiology is very complex, with dynamic progression from preclinical to clinical stages. Several potential therapeutic targets and strategies were tested for AD, in over 2000 clinical trials, but no disease-modifying therapy exists. This failure indicates that AD, as a multifactorial disease, may require multi-targeted approaches and the delivery of therapeutic molecules to the right place and at the right disease stage. Opportunities to meet the challenges of AD therapy appear to come from recent progress in knowledge and methodological advances in the design, synthesis, and targeting of brain mRNA and microRNA with synthetic antisense oligonucleotides (ASOs). Several types of ASOs allow the utilisation of different mechanisms of posttranscriptional regulation and offer enhanced effects over alternative therapeutics. This article reviews ASO-based approaches and targets in preclinical and clinical trials for AD, and presents the future perspective on ASO therapies for AD.

The miRNA Profile of Inflammatory Colorectal Tumors Identify TGF-β as a Companion Target for Checkpoint Blockade Immunotherapy

Extrinsic factors such as expression of PD-L1 (programmed dealth-ligand 1) in the tumor microenvironment (TME) have been shown to correlate with responses to checkpoint blockade therapy. More recently two intrinsic factors related to tumor genetics, microsatellite instability (MSI), and tumor mutation burden (TMB), have been linked to high response rates to checkpoint blockade drugs. These response rates led to the first tissue-agnostic approval of any cancer therapy by the FDA for the treatment of metastatic, MSI-H tumors with anti-PD-1 immunotherapy. But there are still very few studies focusing on the association of miRNAs with immune therapy through checkpoint inhibitors. Our team sought to explore the biology of such tumors further and suggest potential companion therapeutics to current checkpoint inhibitors. Analysis by Pearson Correlation revealed 41 total miRNAs correlated with mutation burden, 62 miRNAs correlated with MSI, and 17 miRNAs correlated with PD-L1 expression. Three miRNAs were correlated with all three of these tumor features as well as M1 macrophage polarization. No miRNAs in any group were associated with overall survival. TGF-β was predicted to be influenced by these three miRNAs (p = 0.008). Exploring miRNA targets as companions to treatment by immune checkpoint blockade revealed three potential miRNA targets predicted to impact TGF-β. M1 macrophage polarization state was also associated with tumors predicted to respond to therapy by immune checkpoint blockade.

Expression of miR-31 in saliva-liquid biopsy in patients with oral squamous cell carcinoma

OBJECTIVES

Oral squamous cell carcinoma (OSCC) is a commonly reported cancer in men and is second only to breast cancer in women in Pakistan.. Investigations for identifying biomarkers of OSCC are essential for diagnostic, therapeutic, or prognostic significance. This study aims to examine the miR-31 expression in the pre- and post-operative OSCC patients and correlate this expression with clinicopathological characteristics.

METHODS

Patients with histopathologically confirmed OSCC who had undergone surgical resections of tumours were recruited. A total of 40 saliva samples (pre- and post-operative) were collected from 19 patients and two healthy individuals. Levels of salivary miR-31 expressions were examined through quantitative reverse transcription polymerase chain reaction.

RESULTS

The salivary miR-31 expression was significantly higher in the preoperative patients than in postoperative patients (p < 0.001). However, no significant correlation had been found between the salivary miR-31 expression and clinicopathological characteristics (p > 0.05).

CONCLUSION

Our data suggest that miR-31 can be used as an adjunct non-invasive marker to monitor surgery outcomes during postoperative follow-up in patients with OSCC.

Identification of clinical trait-related small RNA biomarkers with weighted gene co-expression network analysis for personalized medicine in endocervical adenocarcinoma

Endocervical adenocarcinoma (EAC) is an aggressive type of endocervical cancer. At present, molecular research on EAC mainly focuses on the genome and mRNA transcriptome, the investigation of small RNAs in EAC has not been fully described. Here, we systematically explored small RNAs in 14 EAC patients with different subtypes using small RNA sequencing. MiRNAs and tRNA-derived RNAs (tDRs) accounted for the majority of mapped reads and the total number of miRNAs and tDRs maintained a relative balance. To explore the correlations between small RNAs expression and EAC with different clinical characteristics, we performed the weighted gene co-expression network analysis (WGCNA) and screened for hub small RNAs. From the key modules, we identified 9 small RNAs that were significantly related to clinical characteristics in EAC patients. Gene ontology and pathway analyses revealed that these molecules were involved in the pathogenesis of EAC. Our work provided new insights into EAC pathogenesis and successfully identified several small RNAs as candidate biomarkers for diagnosis and prognosis of EAC.

The tumor suppressor miR-642a-5p targets Wilms Tumor 1 gene and cell-cycle progression in prostate cancer

RNA-based therapeutics are emerging as innovative options for cancer treatment, with microRNAs being attractive targets for therapy development. We previously implicated microRNA-642a-5p (miR-642a-5p) as a tumor suppressor in prostate cancer (PCa), and here we characterize its mode of action, using 22Rv1 PCa cells. In an in vivo xenograft tumor model, miR-642a-5p induced a significant decrease in tumor growth, compared to negative control. Using RNA-Sequencing, we identified gene targets of miR-642a-5p which were enriched for gene sets controlling cell cycle; downregulated genes included Wilms Tumor 1 gene (WT1), NUAK1, RASSF3 and SKP2; and upregulated genes included IGFBP3 and GPS2. Analysis of PCa patient datasets showed a higher expression of WT1, NUAK1, RASSF3 and SKP2; and a lower expression of GPS2 and IGFBP3 in PCa tissue compared to non-malignant prostate tissue. We confirmed the prostatic oncogene WT1, as a direct target of miR-642a-5p, and treatment of 22Rv1 and LNCaP PCa cells with WT1 siRNA or a small molecule inhibitor of WT1 reduced cell proliferation. Taken together, these data provide insight into the molecular mechanisms by which miR-642a-5p acts as a tumor suppressor in PCa, an effect partially mediated by regulating genes involved in cell cycle control; and restoration of miR-642-5p in PCa could represent a novel therapeutic approach.

miR-27b-3p a Negative Regulator of DSB-DNA Repair

Understanding the regulation of DNA repair mechanisms is of utmost importance to identify altered cellular processes that lead to diseases such as cancer through genomic instability. In this sense, miRNAs have shown a crucial role. Specifically, miR-27b-3 biogenesis has been shown to be induced in response to DNA damage, suggesting that this microRNA has a role in DNA repair. In this work, we show that the overexpression of miR-27b-3p reduces the ability of cells to repair DNA lesions, mainly double-stranded breaks (DSB), and causes the deregulation of genes involved in homologous recombination repair (HRR), base excision repair (BER), and the cell cycle. DNA damage was induced in BALB/c-3T3 cells, which overexpress miR-27b-3p, using xenobiotic agents with specific mechanisms of action that challenge different repair mechanisms to determine their reparative capacity. In addition, we evaluated the expression of 84 DNA damage signaling and repair genes and performed pathway enrichment analysis to identify altered cellular processes. Taken together, our results indicate that miR-27b-3p acts as a negative regulator of DNA repair when overexpressed.

A panel of miRNAs as prognostic markers for African-American patients with triple negative breast cancer

BACKGROUND

To investigate the global expression profile of miRNAs, their impact on cellular signaling pathways, and their association with poor prognostic parameters in African-American (AA) patients with triple negative breast cancer (TNBC).

METHODS

Twenty-five samples of AA TNBC patients were profiled for global miRNA expression and stratified considering three clinical-pathological parameters: tumor size, lymph node (LN), and recurrence (REC) status. Differential miRNA expression analysis was performed for each parameter, and their discriminatory power was determined by Receiver Operating Characteristic (ROC) curve analysis. KMplotter was assessed to determine the association of the miRNAs with survival, and functional enrichment analysis to determine the main affected pathways and miRNA/mRNA target interactions.

RESULTS

A panel of eight, 23 and 27 miRNAs were associated with tumor size, LN, and REC status, respectively. Combined ROC analysis of two (miR-2117, and miR-378c), seven (let-7f-5p, miR-1255b-5p, miR-1268b, miR-200c-3p, miR-520d, miR-527, and miR-518a-5p), and three (miR-1200, miR-1249-3p, and miR-1271-3p) miRNAs showed a robust discriminatory power based on tumor size (AUC = 0.917), LN (AUC = 0.945) and REC (AUC = 0.981) status, respectively. Enrichment pathway analysis revealed their involvement in proteoglycans and glycan and cancer-associated pathways. Eight miRNAs with deregulated expressions in patients with large tumor size, positive LN metastasis, and recurrence were significantly associated with lower survival rates. Finally, the construction of miRNA/mRNA networks based in experimentally validated mRNA targets, revealed nodes of critical cancer genes, such as AKT1, BCL2, CDKN1A, EZR and PTEN.

CONCLUSIONS

Altogether, our data indicate that miRNA deregulated expression is a relevant biological factor that can be associated with the poor prognosis in TNBC of AA patients, by conferring to their TNBC cells aggressive phenotypes that are reflected in the clinical characteristics evaluated in this study.

Circular RNA circSP3 promotes hepatocellular carcinoma growth by sponging microRNA-198 and upregulating cyclin-dependent kinase 4

As a new class of endogenous noncoding RNAs, circular RNAs (circRNAs), have been found to influence cell development and function by sponging microRNAs. MicroRNA (miR)-198 is downregulated in various cancers, including hepatocellular carcinoma (HCC). We therefore searched for dysregulated circRNAs that could sponge miR-198 in HCC. By analyzing relevant circRNA databases (circBase, TargetScan and CircInteractome), we found that the miR-198-binding circRNA hsa_circSP3 is upregulated in HCC. CircSP3 expression correlated negatively with miR-198 expression in HCC tissues. Dual luciferase reporter assays indicated that circSP3 bound to miR-198. CircSP3 overexpression in HCC cells induced expression of cyclin-dependent kinase 4, a target gene of miR-198. Silencing circSP3 inhibited HCC cell proliferation and migration by downregulating cyclin-dependent kinase 4, whereas inhibiting miR-198 reversed those effects. In vivo experiments confirmed that circSP3 promoted xenograft tumor growth. These data suggest that circSP3 may be a novel biomarker for HCC.

MicroRNA-199-3p targets Sp1 transcription factor to regulate proliferation and epithelial to mesenchymal transition of human lung cancer cells

The present study was undertaken to study the function of miRNA-199-3p in the regulation of human lung cancer growth and metastasis. The results showed significant (P < 0.05) downregulation of miRNA-199-3p in lung cancer tissues and cell lines. Overexpression of miR-197 caused considerable inhibition of the viability and colony formation of the lung cancer cells. The inhibition of proliferation was found to be due to the arrest of the SK-LU-1 lung cancer cells. At the G2/M phase of the cell cycle. In silico analysis and subsequent the dual-luciferase assays showed that miR-199-3p targets Sp1 at molecular. The expression of Sp1 was significantly (P < 0.05) upregulated in lung cancer cells and tissues. Nonetheless, miR-199-3p overexpression could cause post-transcriptional suppression of Sp1. Silencing of Sp1suppress the proliferation of SK-LU-1 lung cancer cells. However, overexpression Sp1 transcription factor prevents the tumor-suppressive effects of miR-199-3p on lung cancer cells. Additionally, miR-199-3p was found to suppresses the migration, invasion and epithelial-to-mesenchymal transition of human lung cancer cells. Summing up, miRNA-199-3p/SP1 axis controls the growth and metastasis of SK-LU-1 lung cancer cells.

Integrated bioinformatics analysis revealed the regulation of angiogenesis by tumor cells in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer mortality, metastasis accounts for most of the cases. Angiogenesis plays an important role in cancer metastasis, but how tumor cells affect the function of endothelial cells by dictating their microRNA (miRNA) expression remains largely unknown.

Differentially expressed miRNAs (DEMs) were identified through dataset downloaded from the Gene Expression Omnibus (GEO) database and analyzed by GEO2R. We then used online tools to obtain potential targets of candidate miRNAs and functional enrichment analysis, as well as the protein-protein interaction (PPI). Finally, the function of miR-302c-3p was validated through in vitro assay.

In the current study, we found that HCC cells altered miRNA expression profiles of human umbilical vein endothelial cells (HUVECs) and miR-302c-3p was the most down-regulated miRNA in HUVECs when they were co-cultured with HCC-LM3 cells. Functional enrichment analysis of the candidate targets revealed that these genes were involved in epigenetic regulation of gene expression, in particular, cytosine methylation. In addition, PPI network demonstrated distinct roles of genes targeted by miR-302c-3p. Importantly, inhibition of angiogenesis, migration and permeability by the most down-regulated miR-302c-3p in HUVECs was confirmed in vitro. These findings brought us novel insight into the regulation of angiogenesis by HCC cells and provided potential targets for the development of therapeutic strategies.

Circular RNAs as novel potential biomarkers for pancreatic cancer

Pancreatic cancer (PaCa) is the fourth leading cause of cancer-related deaths in the United States, and the vast majority of these malignancies are pancreatic ductal adenocarcinomas (PDAC), but there is still a lack of early detection biomarkers for PaCa. Unlike linear RNAs, circRNAs form covalently closed continuous loops and can act as mammalian gene regulators. They may be diagnostic or predictive biomarkers for some tumors, also be novel potential therapeutic targets in different diseases. This review focuses on (1) the biogenesis of circRNAs, RNA binding proteins (RBPs) and complementary sequences of circRNAs; (2) the characteristics of circRNAs which allow them to interact with miRNAs; (3) the roles of circRNAs playing in the regulation of gene expression, cell behavior and cancer, and their potential role as novel biomarkers and therapeutic targets in pancreatic cancer.

hsa-miR-7-5p suppresses proliferation, migration and promotes apoptosis in hepatocellular carcinoma cell lines by inhibiting SPC24 expression

Emerging evidence suggests that microRNAs (miRNAs) participate in hepatocellular carcinoma (HCC) progression. Nevertheless, the mechanism of miR-7-5p in HCC cells has not been researched. In the research, the underlying biological function of miR-7-5p and SPC24 in HCC was explored. qRT-PCR was performed to measure the miR-7-5p and SPC24 level in HCC tissues and cells. The effect of miR-7-5p on HCC progression was detected by performing CCK-8, BrdU, and transwell assay. The relationship between miR-7-5p and SPC24 was determined using luciferase and RNA pull-down assays. Our findings showed that miR-7-5p was downregulated in HCC whereas SPC24 was upregulated in HCC. It was also showed that miR-7-5p upregulation restricted malignant behaviors of HCC cells, but this inhibitory effect of miR-7-5p could be relieved by its target gene SPC24. In conclusion, this research suggested that by inhibiting SPC24, miR-7-5p could act as a tumor inhibitory factor in HCC.