A MicroRNA signature associated with prognosis and progression in chronic lymphocytic leukemia

Prognostic Values of microRNAs in Colorectal Cancer

The functions of non-coding microRNAs (miRNAs) in tumorigenesis are just beginning to emerge. Previous studies from our laboratory have identified a number of miRNAs that were deregulated in colon cancer cell lines due to the deletion of the p53 tumor suppressor gene. In this study, the in vivo significance of some of these miRNAs was further evaluated using colorectal clinical samples. Ten miRNAs ( hsa-let-7b, hsa-let-7g, hsa-miR-15b, hsa-miR-181b, hsa-miR-191, hsa-miR-200c, hsa-miR-26a, hsa-miR-27a, hsa-miR-30a-5p and hsa-miR-30c) were evaluated for their potential prognostic value in colorectal cancer patients. Forty eight snap frozen clinical colorectal samples (24 colorectal cancer and 24 paired normal patient samples) with detailed clinical follow-up information were selected. The expression levels of 10 miRNAs were quantified via qRT-PCR analysis. The statistical significance of these markers for disease prognosis was evaluated using a two tailed paired Wilcoxon test. A Kaplan-Meier survival curve was generated followed by performing a Logrank test. Among the ten miRNAs, hsa-miR-15b (p = 0.0278), hsa-miR-181b (p = 0.0002), hsa-miR-191 (p = 0.0264) and hsa-miR-200c (p = 0.0017) were significantly over-expressed in tumors compared to normal colorectal samples. Kaplan-Meier survival analysis indicated that hsa-miR-200c was significantly associated with patient survival (p = 0.0122). The patients (n = 15) with higher hsa-miR-200c expression had a shorter survival time (median survival = 26 months) compared to patients (n = 9) with lower expression (median survival = 38 months). Sequencing analysis revealed that hsa-miR-181b (p = 0.0098) and hsa-miR-200c (p = 0.0322) expression were strongly associated with the mutation status of the p53 tumor suppressor gene. Some of these miRNAs may function as oncogenes due to their over-expression in tumors. hsa-miR-200c may be a potential novel prognostic factor in colorectal cancer.

TYRP1 mRNA goes fishing for miRNAs in melanoma

A variety of non-coding RNAs have been reported as endogenous sponges for cancer-modulating miRNAs. However, miRNA trapping by transcripts with protein-coding functions is less understood. The mRNA of TYRP1 is now found to sequester the tumour suppressor miR-16 on non-canonical miRNA response elements in melanoma, thereby promoting malignant growth.

Role of Melt Curve Analysis in Interpretation of Nutrigenomics' MicroRNA Expression Data

This article illustrates the importance of melt curve analysis (MCA) in interpretation of mild nutrogenomic micro(mi)RNA expression data, by measuring the magnitude of the expression of key miRNA molecules in stool of healthy human adults as molecular markers, following the intake of Pomegranate juice (PGJ), functional fermented sobya (FS), rich in potential probiotic lactobacilli, or their combination. Total small RNA was isolated from stool of 25 volunteers before and following a three-week dietary intervention trial. Expression of 88 miRNA genes was evaluated using Qiagen's 96 well plate RT2 miRNA qPCR arrays. Employing parallel coordinates plots, there was no observed significant separation for the gene expression (Cq) values, using Roche 480® PCR LightCycler instrument used in this study, and none of the miRNAs showed significant statistical expression after controlling for the false discovery rate. On the other hand, melting temperature profiles produced during PCR amplification run, found seven significant genes (miR-184, miR-203, miR-373, miR-124, miR-96, miR-373 and miR-301a), which separated candidate miRNAs that could function as novel molecular markers of relevance to oxidative stress and immunoglobulin function, for the intake of polyphenol (PP)-rich, functional fermented foods rich in lactobacilli (FS), or their combination. We elaborate on these data, and present a detailed review on use of melt curves for analyzing nutigenomic miRNA expression data, which initially appear to show no significant expressions, but are actually more subtle than this simplistic view, necessitating the understanding of the role of MCA for a comprehensive understanding of what the collective expression and MCA data collectively imply.

Identification of key miRNA-gene pairs in chronic lymphocytic leukemia through integrated analysis of mRNA and miRNA microarray

The aim of the present study was to explore the miRNA-Gene regulatory mechanism in chronic lymphocytic leukemia (CLL), and identify new targets for the therapy of CLL. The miRNA expression dataset GSE62137 and mRNA expression dataset GSE22529 were downloaded from National Center of Biotechnology Information Gene Expression Omnibus database. In CLL samples compared with normal B cell samples, differentially expressed miRNAs (DEMs) were identified via the GEO2R instrument of GEO and differentially expressed genes (DEGs) were obtained via the limma package of R. Functional enrichment analysis of the DEGs was performed via the Database for Annotation, Visualization and Integrated Discovery. The targets of the DEMs were identified based on the miRNAWalk platform. The overlaps between the DEGs and the targets of the DEMs were selected, and the miRNA-Gene regulatory network was constructed based on the overlaps and the corresponding DEMs. A total of 63 DEMs and 504 DEGs were identified in CLL samples compared with normal B cell samples. Eleven enriched functional clusters of the DEGs were obtained. 405 miRNA-Gene regulatory pairs were identified. The miRNA-Gene regulatory pairs contained 351 target genes of the DEMs, including 9 overlaps with the DEGs. A miRNA-Gene regulatory network was constructed. Bioinformatics methods could help us develop a better understanding of the molecular mechanism of CLL. MiRNAs may play a critical role in regulating the process of CLL. They may affect CLL by regulating the processes of immunoreactivity and protein degradation. Genes such as Neurogenic Locus Notch Homolog Protein 2, PR/SET domain 4 and A-kinase anchoring protein 12 may be their regulating targets in CLL.

Serum MicroRNA-150 Predicts Prognosis for Early-Stage Non-Small Cell Lung Cancer and Promotes Tumor Cell Proliferation by Targeting Tumor Suppressor Gene SRCIN1

This integrative multistage study was aimed to identify circulating microRNAs (miRNAs) as prognostic biomarkers and investigate the treatment target for early-stage non-small cell lung cancer (NSCLC) patients. In stage I-II NSCLC patients, we screened and validated the miRNA ratio signatures predictive of prognosis in serum. In tumor, we found that the expression of miR-150 in identified miRNA signatures was also associated with survival. Increased miR-150 expression promoted NSCLC cell proliferation and migration and vice versa. Specific mRNA cleavage sites targeted by endogenous miR-150 in 3' untranslated region (UTR) of SRCIN1 was identified by utilizing our recently developed novel Stem-Loop-Array reverse-transcription polymerase chain reaction (SLA-RT-PCR) assay. The blocking action of miR-150 resulted in repressed NSCLC cell growth in vitro and knockdown of miR-150 caused substantial tumor volume reduction in vivo. Our findings suggest that miR-150 binding on specific recognition sites in 3' UTR of tumor suppressor gene SRCIN1 present a potential therapeutic target for NSCLC.

MicroRNAs: A novel potential biomarker for diagnosis and therapy in patients with non-small cell lung cancer

BACKGROUND

Lung cancer is still one of the most serious causes of cancer-related deaths all over the world. MicroRNAs (miRNAs) are defined as small non-coding RNAs which could play a pivotal role in post-transcriptional regulation of gene expression. Increasing evidence demonstrated dysregulation of miRNA expression associates with the development and progression of NSCLC.

AIMS

To emphasize a variety of tissue-specific miRNAs, circulating miRNAs and miRNA-derived exosomes could be used as potential diagnostic and therapeutic biomarkers in NSCLC patients.

MATERIALS & METHODS

In the current review, we paid attention to the significant discoveries of preclinical and clinical studies, which performed on tissue-specific miRNA, circulating miRNA and exosomal miRNA. The related studies were obtained through a systematic search of Pubmed, Web of Science, Embase.

RESULTS

A variety of tissue-specific miRNAs and circulating miRNAs with high sensitivity and specificity which could be used as potential diagnostic and therapeutic biomarkers in NSCLC patients. In addition, we emphasize that the miRNA-derived exosomes become novel diagnostic biomarkers potentially in these patients with NSCLC.

CONCLUSION

MiRNAs have emerged as non-coding RNAs, which have potential to be candidates for the diagnosis and therapy of NSCLC.

Urinary cell microRNA-based prognostic classifier for non-muscle invasive bladder cancer

Current prognostic tools for non-muscle invasive bladder cancer (NMIBC) do not have enough discriminative capacity to predict the risk of tumour progression. This study aimed to identify urinary cell microRNAs that may be useful as non-invasive predictive biomarkers of tumour progression in NMIBC patients. To this end, 210 urine samples from NMIBC patients were included in the study. RNA was extracted from urinary cells and expression of 8 microRNAs, previously described by our group, was analysed by quantitative PCR. A tumour progression predicting model was developed by Cox regression analysis and validated by bootstrapping. Regression analysis identified miR-140-5p and miR-92a-3p as independent predictors of tumour progression. The risk score derived from the model containing these two microRNAs was able to discriminate between two groups with a highly significant different probability of tumour progression (HR, 5.204; p<0.001) which was maintained when patients were stratified according to tumour risk. The algorithm was also able to identify two groups with different cancer-specific survival (HR, 3.879; p=0.021). Although the data needs to be externally validated, miRNA analysis in urine appears to be a valuable prognostic tool in NMIBC patients.

Microenvironment regulates the expression of miR-21 and tumor suppressor genes PTEN, PIAS3 and PDCD4 through ZAP-70 in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) cells are highly dependent on microenvironment, being the BCR pathway one key player in this crosstalk. Among proteins participating, ZAP-70 enhances response to microenvironmental stimuli. MicroRNA-21 (miR-21) is overexpressed in diverse neoplasias including CLL, where it has been associated to refractoriness to fludarabine and to shorter time to progression and survival. To further elucidate the role of ZAP-70 in the biology of CLL, we studied its involvement in miR-21 regulation. MiR-21 expression was higher in CLL cells with high ZAP-70. Ectopic expression of ZAP-70 induced transcription of miR-21 via MAPK and STAT3, which subsequently induced downregulation of tumor suppressors targeted by miR-21. The co-culture of primary CLL cells mimicking the microenvironment induced ZAP-70 and miR-21 expression, as well as downregulation of miR-21 targets. Interestingly, the increase in miR-21 after co-culture was significantly impaired by ibrutinib, indicating that the BCR signaling pathway is involved in its regulation. Finally, survival of CLL cells induced by the co-culture correlated with miR-21 upregulation. In conclusion, stimuli from the microenvironment regulate miR-21 and its targeted tumor suppressor genes via a signaling pathway involving ZAP-70, thus contributing to the cytoprotection offered by the microenvironment particularly observed in CLL cells expressing ZAP-70.

Erythroleukemia-historical perspectives and recent advances in diagnosis and management

Acute erythroleukemia is a rare form of acute myeloid leukemia recognized by its distinct phenotypic attribute of erythroblastic proliferation. After a century of its descriptive history, many diagnostic, prognostic, and therapeutic implications relating to this unique leukemia subset remain uncertain. The rarity of the disease and the simultaneous involvement of its associated myeloid compartment have complicated in vitro studies of human erythroleukemia cell lines. Although murine and cell line erythroleukemia models have provided valuable insights into pathophysiology, translation of these concepts into treatment are not forthcoming. Integration of knowledge gained through a careful study of these models with more recent data emerging from molecular characterization will help elucidate key mechanistic pathways and provide a much needed framework that accounts for erythroid lineage-specific attributes. In this article, we discuss the evolving diagnostic concept of erythroleukemia, translational aspects of its pathophysiology, and promising therapeutic targets through an appraisal of the current literature.

The role of a new class of long noncoding RNAs transcribed from ultraconserved regions in cancer

Ultraconserved regions (UCRs) represent a relatively new class of non-coding genomic sequences highly conserved between human, rat and mouse genomes. These regions can reside within exons of protein-coding genes, despite the vast majority of them localizes within introns or intergenic regions. Several studies have undoubtedly demonstrated that most of these regions are actively transcribed in normal cells/tissues, where they contribute to regulate many cellular processes. Interestingly, these non-coding RNAs exhibit aberrant expression levels in human cancer cells and their expression profiles have been used as prognostic factors in human malignancies, as well as to unambiguously distinguish among distinct cancer types. In this review, we first describe their identification, then we provide some updated information about their genomic localization and classification. More importantly, we discuss about the available literature describing an overview of the mechanisms through which some transcribed UCRs (T-UCR) contribute to cancer progression or to the metastatic spread. To date, the interplay between T-UCRs and microRNAs is the most convincing evidence linking T-UCRs and tumorigenesis. The limitations of these studies and the future challenges to be addressed in order to understand the biological role of T-UCRs are also discussed herein. We envision that future efforts are needed to convincingly include this class of ncRNAs in the growing area of cancer therapeutics.

Unique microRNA expression in the colonic mucosa during chronic HIV-1 infection

OBJECTIVE

Chronic HIV-1 infection leads to widespread inflammation and immune dysregulation. The gastrointestinal mucosa, a primary site for HIV-1 replication, is thought to play a significant role in this response. MicroRNAs (miRs) are small noncoding RNAs that regulate gene expression, including immune activation and inflammation. Here we investigate miR expression and function in the colonic mucosa during HIV-1 infection.

DESIGN AND METHODS

Using miR profiling, we examined miR expression in the colonic mucosa of HIV-infected patients. These miRs were further parsed to identify those that most likely function in HIV-related inflammation. Using bioinformatics tools, we identified potential target genes which were confirmed using in-vitro functional testing.

RESULTS

We identified 12 miRs that were differentially expressed in the colonic mucosa of HIV-infected patients with high versus undetectable plasma viral concentrations. Of these, both miR-26a and miR-29a were downregulated in untreated HIV-1 infection, yet not in the colonic mucosa from inflammatory bowel disease. This downregulation occurs within the first hours after infection. These miRs were further shown to directly target IL-6 and STAT3, respectively, with similar changes confirmed in an ex-vivo explant infection model.

CONCLUSION

miR-26a and miR-29a levels are decreased in the colonic mucosa during chronic HIV-1 infection, and this change may be initiated during acute infection. Both miRs de-repress the IL-6/STAT3 signaling pathway, which could contribute to increased inflammation during infection. These miRs may represent novel therapeutic targets for HIV-1-associated inflammation in the colonic mucosa.

Translational applications of microRNAs in cancer, and therapeutic implications

The search for targeted novel therapies for cancer is ongoing. MicroRNAs (miRNAs) display a number of characteristics making them an attractive and realisable option. In this review, we explore these applications, ranging from diagnostics, prognostics, disease surveillance, to being a primary therapy or a tool to sensitise patients to treatment modalities such as chemotherapy and radiotherapy. We take a particular perspective towards miRNAs and their impact on rare cancers. Advancement in the delivery of miRNAs, from viral vectors and liposomal delivery to nanoparticle based, has led to a number of pre-clinical and clinical applications for microRNA cancer therapeutics. This is promising, especially in the setting of rare cancers.

MicroRNAs, a subpopulation of regulators, are involved in breast cancer progression through regulating breast cancer stem cells

Cancer stem cells (CSCs; also known as tumor-initiating cells) are essential effectors of tumor progression due to their self-renewal capacity, differentiation potential, tumorigenic ability and resistance to chemotherapy, all of which contribute to cancer relapse, metastasis and a poor prognosis. Breast cancer stem cells (BCSCs) have been identified to be involved in the processes of BC initiation, growth and recurrence. MicroRNAs (miRNAs) are a class of non-coding small RNAs of 19-23 nucleotides in length that regulate gene expression at the post-transcriptional level through various mechanisms, and serve critical roles in cancer progression. miRNAs have been demonstrated to elicit effects on BCSCs characteristics via the targeting of oncogenes or tumor suppressor genes. The present study focused on the effect of miRNAs on BCSC, including BCSC formation, self-renewal and differentiation, by which miRNAs may inhibit BCSC invasion and metastasis, modulate clonogenicity and tumorigenicity of BCSCs as well as regulate chemotherapy resistance to BC. Through an improved understanding of the association between BCSCs and miRNAs, a novel and safer therapeutic target for BC may be identified.

Expression Levels and Clinical Significance of miR-21-5p, miR-let-7a, and miR-34c-5p in Laryngeal Squamous Cell Carcinoma

Objective

Altered microRNAs (miRNAs) expression has been found in many cancer types, including laryngeal squamous cell carcinoma (LSCC). The aim of this study was to determine the role and clinical value of three LSCC-related miRs, such as miR-21-5p, miR-let-7a, and miR-34c-5p in a homogeneous cohort of patients with primary LSCC treated by primary surgery.

Methods

Expression levels of miR-21-5p, miR-let-7a, and miR-34c-5p were detected in 43 pairs of LSCC and adjacent normal tissues by reverse-transcription quantitative PCR. Overall survival and disease-free survival were evaluated using the Kaplan–Meier method, and multivariate analysis was performed using the Cox proportional hazard analysis.

Results

miR-21-5p is significantly upregulated, while miR-let-7a is significantly downregulated in LSCC tumor tissues compared with the corresponding adjacent normal tissues. The downregulation of miR-34c-5p expression significantly correlated with a shorter disease-free survival and, in the multivariate analysis, low miR-34c-5p expression was associated with an increased risk of recurrence.

Conclusions

miR-21-5p, miR-let-7a, and miR-34c-5p seem to play a critical role in LSCC carcinogenesis and might have a diagnostic and prognostic clinical value. The miR-let-7a levels could have a predictive role for lymph node metastases and miR-34c-5p might be a promising biomarker of patient outcome.

miRNAs and ovarian cancer: An overview

Ovarian cancer (OC) is the sixth most common cancer in women globally. However, even with the advances in detection and therapeutics it still represents the most dangerous gynecologic malignancy in women of the industrialized countries. The discovery of micro-RNAs (miRNA), a small noncoding RNA molecule targeting multiple mRNAs and regulation of gene expression by triggering translation repression and/or RNA degradation, has revealed the existence of a new array for regulation of genes involved in cancer. This review summarizes the current knowledge regarding the role of miRNAs expression in OC. It also provides information about potential clinical relevance of circulating miRNAs for OC diagnosis, prognosis, and therapeutics. The identification of functional targets for miRNAs represents a major obstacle in our understanding of microRNA function in OC, but significant progress is being made. The better understanding of the role of microRNA expression in ovarian cancer may provide new array for the detection, diagnosis, and therapy of the OC.

STAT3 is required for MiR-17-5p-mediated sensitization to chemotherapy-induced apoptosis in breast cancer cells

Signal transducer and activator of transcription 3 (STAT3) controls cell survival, growth, migration, and invasion. Here, we observed that STAT3 exerted anti-apoptotic effects in breast cancer cells. On the other hand, miR-17-5p induced apoptosis in breast cancer cells, and overexpression of miR-17-5p sensitized MCF-7 cells to paclitaxel-induced apoptosis via STAT3. Overexpression of STAT3 in MCF-7 cells decreased paclitaxel-induced apoptosis, but STAT3 knockout abolished the miR-17-5p-induced increases in apoptosis. Finally, miR-17-5p promoted apoptosis by increasing p53 expression, which was inhibited by STAT3. These results demonstrate a novel pathway via which miR-17-5p inhibits STAT3 and increases p53 expression to promote apoptosis in breast cancer cells.

microRNA-375 inhibits colorectal cancer cells proliferation by downregulating JAK2/STAT3 and MAP3K8/ERK signaling pathways

MicroRNA-375 is involved in many types of alimentary system cancers. Our previous studies showed that microRNA-375 was significantly down-regulated in carcinoma tissues compared with para-carcinoma tissues, which strongly indicates that microRNA-375 might suppress the occurrence and development of colorectal cancer. However, the mechanism underlying the microRNA-375 regulation in colorectal cancer remains unclear. In this study, we first sorted out jak2, map3k8 and atg7 as microRNA-375 targeted genes from multiple databases, and found that jak2, map3k8 and their downstream genes stat3 and erk were up-regulated in carcinoma tissues. Secondly, we over-expressed microRNA-375 in colorectal cancer cell lines (HCT116, Caco2 and HT29). Our results showed that in microRNA-375 over-expressing cells, JAK2/STAT3 and MAP3K8/ERK proteins were down-regulated, cell proliferation was inhibited, cell migration rate did not change. There was no significant difference on ATG7 expression between the control group and microRNA-375 over-expressing HT29/Caco2 cells, whereas microRNA-375 down-regulated ATG7 specifically in HCT116 cells. Finally, we demonstrated that expressing microRNA-375 suppressed tumor formation in nude mice. In conclusion, microRNA-375 might function as a tumor-repressive gene to inhibit cell proliferation, mainly through targeting both JAK2/STAT3 and MAP3K8/ERK signaling pathways in colorectal cancer. These findings suggest miR-375 as a promising diagnostic marker and a therapeutic drug for colorectal cancer.

MiR-15a/16 deficiency enhances anti-tumor immunity of glioma-infiltrating CD8+ T cells through targeting mTOR

MiR-15a/16, a miRNA cluster located at chromosome 13q14, has been reported to act as an immune regulator in inflammatory disorders besides its aberrant expression in cancers. However, little is known about its regulation in tumor-infiltrating immune cells. In our study, using an orthotropic GL261 mouse glioma model, we found that miR-15a/16 deficiency in host inhibited tumor growth and prolonged mice survival, which might be associated with the accumulation of tumor-infiltrating CD8+ T cells. More importantly, tumor-infiltrating CD8+ T cells without miR-15a/16 showed lower expression of PD-1, Tim-3 and LAG-3, and stronger secretion of IFN-γ, IL-2 and TNF-α than WT tumor-infiltrating CD8+ T cells. Also, our in vitro experiments further confirmed that miR-15a/16^-/- CD8+ T displayed higher active phenotypes, more cytokines secretion and faster expansion, compared to WT CD8+ T cells. Mechanismly, mTOR was identified as a target gene of miR-15a/16 to negatively regulate the activation of CD8+ T cells. Taken together, these data suggest that miR-15a/16 deficiency resists the exhaustion and maintains the activation of glioma-infiltrating CD8+ T cells to alleviate glioma progression via targeting mTOR. Our findings provide evidence for the potential immunotherapy through targeting miR-15a/16 in tumor-infiltrating immune cells.

MicroRNAs and Cancer: A Long Story for Short RNAs

More than six decades ago Watson and Crick published the chemical structure of DNA. This discovery revolutionized our approach to medical science and opened new perspectives for the diagnosis and treatment of many diseases including cancer. Since then, progress in molecular biology, together with the rapid advance of technologies, allowed to clone hundreds of protein-coding genes that were found mutated in all types of cancer. Normal and aberrant gene functions, interactions, and mechanisms of mutations were studied to identify the intricate network of pathways leading to cancer. With the acknowledgment of the genetic nature of cancer, new diagnostic, prognostic, and therapeutic strategies have been attempted and developed, but very few have found their way in the clinical field. In an effort to identify new translational targets, another great discovery has changed our way to look at genes and their functions. MicroRNAs have been the first noncoding genes involved in cancer. This review is a brief chronological history of microRNAs and cancer. Through the work of few of the greatest scientists of our times, this chapter describes the discovery of microRNAs from C. elegans to their debut in cancer and in the medical field, the concurrent development of technologies, and their future translational applications. The purpose was to share the exciting path that lead to one of the most important discoveries in cancer genetics in the past 20 years.

MicroRNA: an important regulator in acute myeloid leukemia

MicroRNAs (miRNAs) are a general class of endogenous non-coding RNAs with a length of 22 nucleotides, widely existing in diverse species and playing important roles in malignancies initiation and progression. MiRNAs are essential to many in vivo biological processes such as cell proliferation, apoptosis, immune response, and tumorigenesis. Significant progress till date has been made in understanding the roles of microRNAs in normal hematopoiesis and hematopoietic malignant diseases. In this review, we summarize the particular signatures of microRNAs in acute myeloid leukemia (AML) patients with specific karyotype and the clinical significance of microRNAs in early diagnosis and treatment. MicroRNAs hypermethylation was also proved to correlate with the pathogenesis of AML. However, the target genes and exact pathways of microRNAs participating in these processes are still unknown and more efforts need to be made in the near future.

Anti-leukemic activity of microRNA-26a in a chronic lymphocytic leukemia mouse model

Dysregulation of microRNAs (miRNAs) plays an important role in the pathogenesis of chronic lymphocytic leukemia (CLL). The Eμ-TCL1 transgenic mouse develops a form of leukemia that is similar to the aggressive type of human B-CLL, and this valuable model has been widely used for testing novel therapeutic approaches. Here, we adopted this model to investigate the potential effects of miR-26a, miR-130an and antimiR-155 in CLL therapy. Improved delivery of miRNA molecules into CLL cells was obtained by developing a novel system based on lipid nanoparticles conjugated with an anti-CD38 monoclonal antibody. This methodology has proven to be highly effective in delivering miRNA molecules into leukemic cells. Short- and long-term experiments showed that miR-26a, miR-130a and anti-miR-155 increased apoptosis after in vitro and in vivo treatment. Of this miRNA panel, miR-26a was the most effective in reducing leukemic cell expansion. Following long-term treatment, apoptosis was readily detectable by analyzing cleavage of PARP and caspase-7. These effects could be directly attributed to miR-26a, as confirmed by significant downregulation of its proven targets, namely cyclin-dependent kinase 6 and Mcl1. The results of this study are relevant to two distinct areas. The first is related to the design of a technical strategy and to the selection of CD38 as a molecular target on CLL cells, both consenting efficient and specific intracellular transfer of miRNA. The original scientific finding inferred from the above approach is that miR-26a can elicit in vivo anti-leukemic activities mediated by increased apoptosis.

microRNAs in Cancer Susceptibility

microRNAs (miRNAs) are a small RNA species without protein-coding potential. However, they are key modulators of protein translation. Many studies have linked miRNAs with cancer initiation, progression, diagnosis, and prognosis, and recent studies have also linked them with cancer etiology and susceptibility, especially through single-nucleotide polymorphisms (SNPs). This review discusses some of the recent advances in miRNA-SNP literature-including SNPs in miRNA genes, miRNA target sites, and the processing machinery. In addition, we highlight some emerging areas of interest, including isomiRs and non-3'UTR focused miRNA-binding mechanisms that could provide further novel insight into the relationship between miR-SNPs and cancer. Finally, we note that additional epidemiological and experimental research is needed to close the gap in our understanding of the genotype-phenotype relationship between miRNA-SNPs and cancer.

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.

Tumor-derived exosomes modulate PD-L1 expression in monocytes

In chronic lymphocytic leukemia (CLL), monocytes and macrophages are skewed toward protumorigenic phenotypes, including the release of tumor-supportive cytokines and the expression of immunosuppressive molecules such as programmed cell death 1 ligand 1 (PD-L1). To understand the mechanism driving protumorigenic skewing in CLL, we evaluated the role of tumor cell-derived exosomes in the cross-talk with monocytes. We carried out RNA sequencing and proteome analyses of CLL-derived exosomes and identified noncoding Y RNA hY4 as a highly abundant RNA species that is enriched in exosomes from plasma of CLL patients compared with healthy donor samples. Transfer of CLL-derived exosomes or hY4 alone to monocytes resulted in key CLL-associated phenotypes, including the release of cytokines, such as C-C motif chemokine ligand 2 (CCL2), CCL4, and interleukin-6, and the expression of PD-L1. These responses were abolished in Toll-like receptor 7 (TLR7)-deficient monocytes, suggesting exosomal hY4 as a driver of TLR7 signaling. Pharmacologic inhibition of endosomal TLR signaling resulted in a substantially reduced activation of monocytes in vitro and attenuated CLL development in vivo. Our results indicate that exosome-mediated transfer of noncoding RNAs to monocytes contributes to cancer-related inflammation and concurrent immune escape via PD-L1 expression.

MicroRNA‑329 serves a tumor suppressive role in colorectal cancer by directly targeting transforming growth factor beta‑1

Colorectal cancer (CRC) is the third most common type of diagnosed cancer and the fourth leading cause of cancer‑associated mortalities worldwide. Increasing studies have demonstrated that the deregulation of microRNAs (miRNAs or miRs) is associated with the occurrence and development of multiple types of human cancer, including CRC. miR‑329 has been identified to be downregulated in various types of cancer; however, its expression pattern, functions and mechanisms in CRC remain unclear. The present study demonstrated that miR‑329 was lowly expressed in CRC tissue samples and cell lines. Low expression of miR‑329 was correlated with tumor‑node‑metastasis stage and lymph node metastasis in patients with CRC. In vitro experiments revealed that resumption expression of miR‑329 suppressed cell proliferation and invasion in CRC. Furthermore, the results of the present study indicated that miR‑329 targets transforming growth factor‑β1 (TGF‑β1) directly in vitro. TGF‑β1 was demonstrated to be upregulated in CRC tissue samples and inversely correlated with miR‑329 expression. Upregulation of TGF‑β1 was able to partially counteract the antitumor roles of miR‑329 on CRC cell proliferation and invasion. The results of the current study revealed that miR‑329 suppresses CRC cell proliferation and invasion through targeting TGF‑β1, thus suggesting that targeting miR‑329/TGF‑β1 may provide a novel effective therapeutic approach for the treatment of patients with CRC.

Polymorphisms in Non-coding RNA Genes and Their Targets Sites as Risk Factors of Sporadic Colorectal Cancer

Colorectal cancer (CRC) is a complex disease that develops as a consequence of both genetic and environmental risk factors in interplay with epigenetic mechanisms, such as microRNAs (miRNAs). CRC cases are predominantly sporadic in which the disease develops with no apparent hereditary syndrome. The last decade has seen the progress of genome-wide association studies (GWAS) that allowed the discovery of several genetic regions and variants associated with weak effects on sporadic CRC. Collectively these variants may enable a more accurate prediction of an individual's risk to the disease and its prognosis. However, the number of variants contributing to CRC is still not fully explored.SNPs in genes encoding the miRNA sequence or in 3'UTR regions of the corresponding binding sites may affect miRNA transcription, miRNA processing, and/or the fidelity of the miRNA-mRNA interaction. These variants could plausibly impact miRNA expression and target mRNA translation into proteins critical for cellular integrity, differentiation, and proliferation.In the present chapter, we describe the different aspects of variations related to miRNAs and other non-coding RNAs (ncRNAs) and evidence from studies investigating these candidate genetic alterations in support to their role in CRC development and progression.

Exportin 1 (XPO1) inhibition leads to restoration of tumor suppressor miR-145 and consequent suppression of pancreatic cancer cell proliferation and migration

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer related deaths in the United States with a majority of these patients dying from aggressively invasive and metastatic disease. There is growing evidence that suggests an important role for microRNAs (miRNAs) in the pathobiology of aggressive PDAC. In this study, we found that the expression of miR-145 was significantly lower in PDAC cells when compared to normal pancreatic duct epithelial cells. Here we show that inhibition of the nuclear exporter protein exportin 1 (XPO1; also known as chromosome maintenance region 1 [CRM1]) by siRNA knockdown or by the Selective Inhibitor of Nuclear Export (SINE) compound (KPT-330; selinexor) increases miR-145 expression in PDAC cells resulting in the decreased cell proliferation and migration capacities. A similar result was obtained with forced expression of miR-145 in PDAC cells. To this end, SINE compound treatment mediated the down-regulation of known miR-145 targets genes including EGFR, MMP1, MT-MMP, c-Myc, Pak4 and Sox-2. In addition, selinexor induced the expression of two important tumor suppressive miRNAs miR-34c and let-7d leading to the up-regulation of p21^WAF1. These results are the first to report that targeted inhibition of the nuclear export machinery could restore tumor suppressive miRNAs in PDAC that warrants further clinical investigations.

Preliminary data on microRNA expression profiles in a group of South African patients diagnosed with chronic myeloid leukaemia

Micro-ribonucleic acids (miRNAs) are small functional non-coding RNAs that downregulate gene expression at the post-transcriptional level. Abnormal expression of specific miRNAs has been recorded in chronic lymphocytic leukaemia, other non-Hodgkin B-cell lymphomas, lung cancer and chronic myeloid leukaemia (CML). The aim of this study was to compare miRNA expression profiles among patients with newly diagnosed CML, those on established therapy with imatinib mesylate, and healthy individuals. The expression of 88 miRNAs was evaluated in a total of nine samples divided into three groups: Group 1 comprised three samples collected from newly diagnosed CML patients; group 2 consisted of three samples collected from patients on therapy; the remaining three samples were collected from healthy volunteers (control group). Total RNA was extracted from whole blood and reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) was performed on the LightCycler® 480 platform using Human Serum & Plasma miRNA PCR Arrays. In group 1, only SNORD44 was downregulated, while hsa-miR-372 and hsa-miR-375 were found to be significantly upregulated compared with the control group. By contrast, 49 miRNAs were significantly upregulated in group 2 compared with the control group. miRNAs hsa-miR-106b, hsa-miR-21, hsa-miR-221, hsa-miR-10a, hsa-miR-193a-5p and hsa-miR-30e were expressed in group 2. Therefore, miRNA expression profiles differed between the two patient groups.

Prognostic value of the MicroRNA-29 family in multiple human cancers: A meta-analysis and systematic review

MicroRNAs (miRNAs) in cancer development have attracted much attention in recent years. miR-29 is known to critically affect cancer progression by functioning as a tumor suppressor. However, it may also act as an oncogene under certain situations. The prognostic value of the miR-29 family in cancer progression is still under debate and reported results are inconsistent. Therefore, we reported here a meta-analysis and systematic review to analyze the prognostic role of the miR-29 family in cancer. We screened 20 published studies and calculated pooled hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) for overall survival (OS) or disease-free survival/recurrence-free survival (DFS/RFS). Our results showed that a low or absent expression of miR-29 family was significantly associated with poor OS (HR, 1.57; 95%CI, 1.18-2.08), and inferior to 5-year DFS/RFS (HR, 1.89; 95%CI, 1.47-2.44). Analysis of individual miR-29 subtypes indicated that the low expression of miR-29a/b/c subtypes correlated with poor 5-year OS (miR-29a: HR, 1.99; 95%CI, 1.41-2.80; miR-29b: HR, 1.60; 95%CI, 1.18-2.17; miR-29c: HR, 1.69; 95%CI, 1.00-2.86), as well as poor 5-year DFS/RFS (miR-29b: HR, 1.70; 95%CI, 1.27-2.27). Ethnicity analysis demonstrated Asian patients with low expression of miR-29 were significantly correlated with poor OS (HR, 1.61; 95%CI, 1.16-2.23) and 5-year DFS/RFS (HR, 2.03; 95%CI, 1.50-2.74). Taken together, our analysis indicates that the low expression of miR-29 is associated with aggressiveness and poor prognosis of malignant neoplasms. More importantly, miR-29 might serve as a key biomarker for predicting the recurrence and progression of human cancers.

Circulating microRNA as a marker for predicting liver disease progression in patients with chronic hepatitis B

INTRODUCTION

Hepatitis B virus (HBV) constitutes an important risk factor for cirrhosis and hepatocellular carcinoma (HCC). The link between circulating microRNAs and HBV has been previously reported, although not as a marker of liver disease progression in chronic hepatitis B (CHB). The aim of this study was to characterize miRNA expression profiles between CHB with and without cirrhosis or HCC.

METHODS:

A total of 12 subjects were recruited in this study. We employed an Affymetrix Gene Chip miRNA 3.0 Array to provide universal miRNA coverage. We compared microRNA expression profiles between CHB with and without cirrhosis/HCC to discover possible prognostic markers associated with the progression of CHB.

RESULTS:

Our results indicated 8 differently expressed microRNAs, of which miRNA-935, miRNA-342, miRNA-339, miRNA-4508, miRNA-3615, and miRNA-3200 were up-regulated, whereas miRNA-182 and miRNA-4485 were down-regulated in patients with CHB who progressed to cirrhosis/HCC as compared to those without progression.

CONCLUSIONS:

We demonstrated the differential expression of miRNA-935, miRNA-342, miRNA-339, miRNA-4508, miRNA-3615, miRNA-3200, miRNA-182, and miRNA-4485 between patients with HBV without cirrhosis/HCC and those who had progressed to these more severe conditions. These miRNAs may serve as novel and non-invasive prognostic markers for early detection of CHB-infected patients who are at risk of progression to cirrhosis and/or HCC.

Regulation of Autophagy by MiRNAs and Their Emerging Roles in Tumorigenesis and Cancer Treatment

Autophagy is a conserved catabolic process for the degradation and recycling of cytosolic components or organelles through a lysosome-dependent pathway. Autophagy can be induced in response to multiple stress conditions, such as nutrient deprivation, hypoxia, energy depletion, etc. As a result, autophagy can regulate many biological processes, including cell survival, metabolism, differentiation, senescence, and cell death. MicroRNAs (MiRNAs) are small noncoding molecules that regulate gene expression by silencing mRNA targets. MiRNA dysregulation exhibits great regulatory potential during organismal development, hematopoiesis, immunity, cell proliferation and death, and autophagy. Recently, increasing studies have linked MiRNAs to autophagic regulation during cancer initiation and development. Although the relationship between MiRNAs and autophagy is quite complicated and has not been well elucidated, MiRNAs may underlie key aspects of autophagy and cancer biology. Increasing evidence shows that MiRNAs play important roles as both oncogenic MiRNAs and tumor suppressive MiRNAs in cancer initiation and development. Thus, understanding the novel relationship between MiRNAs and autophagy may allow us to develop promising cancer biomarkers and therapeutic targets.

MicroRNA-320 inhibits cell proliferation, migration and invasion in retinoblastoma by targeting specificity protein 1

Research into the expression and function of microRNAs (miRNAs/miR) in human cancer has provided novel insights into the molecular mechanisms underlying carcinogenesis and cancer progression. Aberrant miRNA expression has been reported in retinoblastoma (RB) and several other types of human cancer. The present study demonstrated that miR‑320 is significantly downregulated in RB tissues and cell lines. Furthermore, overexpression of miR‑320 was demonstrated to inhibit proliferation, migration and invasion of RB cells. Bioinformatic analysis identified specificity protein 1 (SP1) as a potential target gene of miR‑320. Luciferase reporter assay confirmed that the SP1 3'‑untranslated region contains a direct binding site for miR‑320, and restoration of miR‑320 expression decreased the mRNA and protein expression levels of SP1. Notably, SP1 silencing induced a similar effect on the proliferation, migration and invasion of RB cells as that observed with miR‑320 overexpression, further supporting the hypothesis that SP1 is a direct functional target of miR‑320 in RB. In conclusion, these findings indicate that miR‑320 may be an effective therapeutic target for the treatment of RB.

Significance of Inactivated Genes in Leukemia: Pathogenesis and Prognosis

Epigenetic and genetic alterations are two mechanisms participating in leukemia, which can inactivate genes involved in leukemia pathogenesis or progression. The purpose of this review was to introduce various inactivated genes and evaluate their possible role in leukemia pathogenesis and prognosis. By searching the mesh words "Gene, Silencing AND Leukemia" in PubMed website, relevant English articles dealt with human subjects as of 2000 were included in this study. Gene inactivation in leukemia is largely mediated by promoter's hypermethylation of gene involving in cellular functions such as cell cycle, apoptosis, and gene transcription. Inactivated genes, such as ASPP1, TP53, IKZF1 and P15, may correlate with poor prognosis in acute lymphoid leukemia (ALL), chronic lymphoid leukemia (CLL), chronic myelogenous leukemia (CML) and acute myeloid leukemia (AML), respectively. Gene inactivation may play a considerable role in leukemia pathogenesis and prognosis, which can be considered as complementary diagnostic tests to differentiate different leukemia types, determine leukemia prognosis, and also detect response to therapy. In general, this review showed some genes inactivated only in leukemia (with differences between B-ALL, T-ALL, CLL, AML and CML). These differences could be of interest as an additional tool to better categorize leukemia types. Furthermore; based on inactivated genes, a diverse classification of Leukemias could represent a powerful method to address a targeted therapy of the patients, in order to minimize side effects of conventional therapies and to enhance new drug strategies.

The effects of microRNAs on glucocorticoid responsiveness

PURPOSE

Glucocorticoids (GCs) are of wide usage in the clinical treatment of lymphoblastic malignancies such as acute lymphoblastic leukemia. However, individually distinctive responsiveness to the GC therapy may attenuate their clinical efficacy, and more reliable predictor for GC resistance is still eagerly needed. Recent studies indicate that microRNAs (miRNAs), which demonstrate regulatory functions targeting mRNAs during the post-transcription, involved in the regulation of GCs sensitivity through several mechanisms, especially adjusting the magnitude of GC receptors (GRs), which mediates the cellular effects of GCs and plays a pivotal role in GCs sensitivity, inspiring that special miRNAs pattern could serve as the biomarkers to predict GC sensitivity and bring forth potential strategies for overcoming drug resistance. In this review, we discuss related miRNAs and their diverse effects exerted on multifaceted complexity of GCs responsiveness for further exploiting the molecular mechanism of GC resistance and future construction of the molecular diagnostic method and reverse GC resistance.

METHODS

We have reviewed and searched for eligible literature relating to the effects of microRNAs on GC responsiveness from systematic PubMed searches.

RESULTS

GC response can be mediated by miRNAs through influence on GC signaling pathway, leading to diverse glucocorticoid responsiveness. Mutations in miRNA gene also influence GC response. As well, GCs regulate the function of several miRNAs, and suggesting a bidirectional influence among them.

CONCLUSIONS

It is possible and necessary that miRNAs serve as stable biomarkers and GC resistant patients would benefit from an effective and early screening test.

IFI16 reduced expression is correlated with unfavorable outcome in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults. Its clinical course is typically indolent; however, based on a series of pathobiological, clinical, genetic, and phenotypic parameters, patient survival varies from less than 5 to more than 20 years. In this paper, we show for the first time that the expression of the interferon-inducible DNA sensor IFI16, a member of the PYHIN protein family involved in proliferation inhibition and apoptosis regulation, is associated with the clinical outcome in CLL. We studied 99 CLLs cases by immunohistochemistry and 10 CLLs cases by gene expression profiling. We found quite variable degrees of IFI16 expression among CLLs cases. Noteworthy, we observed that a reduced IFI16 expression was associated with a very poor survival, but only in cases with ZAP70/CD38 expression. Furthermore, we found that IFI16 expression was associated with a specific gene expression signature. As IFI16 can be easily detected by immunohistochemistry or flow cytometry, it may become a part of phenotypic screening in CLL patients if its prognostic role is confirmed in independent series.

A mutation in porcine pre-miR-15b alters the biogenesis of MiR-15b\16-1 cluster and strand selection of MiR-15b

MicroRNAs (miRNAs) are small non-coding RNAs that are involved in translational regulation of the messenger RNA molecules. Sequence variations in the genes encoding miRNAs could influence their biogenesis and function. MiR-15b plays an important role in cellular proliferation, apoptosis and the cell cycle. Here, we report the identification of a C58T mutation in porcine pre-miR-15b. Through in vitro and in vivo experiments, we determined that this mutation blocks the transition from pri-miRNA to pre-miRNA, alters the strand selection between miR-15b-5p and miR-15b-3p, and obstructs biogenesis of the downstream miR-16-1. These results serve to highlight the importance of miRNA mutations and their impacts on miRNA biogenesis.

Genetic variation and RNA structure regulate microRNA biogenesis

MiRNA biogenesis is highly regulated at the post-transcriptional level; however, the role of sequence and secondary RNA structure in this process has not been extensively studied. A single G to A substitution present in the terminal loop of pri-mir-30c-1 in breast and gastric cancer patients had been previously described to result in increased levels of mature miRNA. Here, we report that this genetic variant directly affects Drosha-mediated processing of pri-mir-30c-1 in vitro and in cultured cells. Structural analysis of this variant revealed an altered RNA structure that facilitates the interaction with SRSF3, an SR protein family member that promotes pri-miRNA processing. Our results are compatible with a model whereby a genetic variant in pri-mir-30c-1 leads to a secondary RNA structure rearrangement that facilitates binding of SRSF3 resulting in increased levels of miR-30c. These data highlight that primary sequence determinants and RNA structure are key regulators of miRNA biogenesis.

Prognostic role of circulating exosomal miRNAs in multiple myeloma

Exosomes, secreted by several cell types, including cancer cells, can be isolated from the peripheral blood and have been shown to be powerful markers of disease progression in cancer. In this study, we examined the prognostic significance of circulating exosomal microRNAs (miRNAs) in multiple myeloma (MM). A cohort of 156 patients with newly diagnosed MM, uniformly treated and followed, was studied. Circulating exosomal miRNAs were isolated and used to perform a small RNA sequencing analysis on 10 samples and a quantitative reverse transcription polymerase chain reaction (qRT-PCR) array on 156 samples. We studied the relationship between miRNA levels and patient outcomes, including progression-free survival (PFS) and overall survival (OS). We identified miRNAs as the most predominant small RNAs present in exosomes isolated from the serum of patients with MM and healthy controls by small RNA sequencing of circulating exosomes. We then analyzed exosomes isolated from serum samples of 156 patients using a qRT-PCR array for 22 miRNAs. Two of these miRNAs, let-7b and miR-18a, were significantly associated with both PFS and OS in the univariate analysis and were still statistically significant after adjusting for the International Staging System and adverse cytogenetics in the multivariate analysis. Our findings support the use of circulating exosomal miRNAs to improve the identification of patients with newly diagnosed MM with poor outcomes. The results require further validation in other independent prospective MM cohorts.

microRNA-497 overexpression decreases proliferation, migration and invasion of human retinoblastoma cells via targeting vascular endothelial growth factor A

The expression level and roles of microRNA-497 (miR-497) have been frequently reported in previous studies on cancer. However, its expression, function and associated molecular mechanisms in retinoblastoma remain unknown. In the present study, miR-497 expression levels in human retinoblastoma tissues, normal retinal tissues and retinoblastoma cell lines were determined using reverse transcription-quantitative polymerase chain reaction. In addition, a Cell Counting Kit-8 assay, cell migration assay, cell invasion assay, western blot analysis and Dual-Luciferase reporter assay were used to explore the expression, functions and molecular mechanisms of miR-497 in human retinoblastoma. It was demonstrated that miR-497 was significantly downregulated in retinoblastoma tissues and cell lines compared with normal retinal tissues. Ectopic expression of miR-497 decreased the proliferation, migration and invasion of retinoblastoma cells. Furthermore, VEGFA was verified as a potential direct target of miR-497 in vitro. Taken together, the results indicate that miR-497 functions as a tumor suppressor in the carcinogenesis and progression of retinoblastoma via targeting VEGFA. miR-497 should be investigated as a potential therapeutic target for the treatment of retinoblastoma.

A Macro View of MicroRNAs: The Discovery of MicroRNAs and Their Role in Hematopoiesis and Hematologic Disease

MicroRNAs (MiRNAs) are a class of endogenously encoded ~22 nucleotide, noncoding, single-stranded RNAs that contribute to development, body planning, stem cell differentiation, and tissue identity through posttranscriptional regulation and degradation of transcripts. Given their importance, it is predictable that dysregulation of MiRNAs, which target a wide variety of transcripts, can result in malignant transformation. In this review, we explore the discovery of MiRNAs, their mechanism of action, and the tools that aid in their discovery and study. Strikingly, many of the studies that have expanded our understanding of the contributions of MiRNAs to normal physiology and in the development of diseases have come from studies in the hematopoietic system and hematologic malignancies, with some of the earliest identified functions for mammalian MiRNAs coming from observations made in leukemias. So, with a special focus on the hematologic system, we will discuss how MiRNAs contribute to differentiation of stem cells and how dysregulation of MiRNAs contributes to the development of malignancy, by providing examples of specific MiRNAs that function as oncogenes or tumor suppressors, as well as of defects in MiRNA processing. Finally, we will discuss the promise of MiRNA-based therapeutics and challenges for the future study of disease-causing MiRNAs.

Long non-coding RNAs in B-cell malignancies: a comprehensive overview

B-cell malignancies constitute a large part of hematological neoplasias. They represent a heterogeneous group of diseases, including Hodgkin's lymphoma, most non-Hodgkin's lymphomas (NHL), some leukemias and myelomas. B-cell malignancies reflect defined stages of normal B-cell differentiation and this represents the major basis for their classification. Long non-coding RNAs (lncRNAs) are non-protein-coding transcripts longer than 200 nucleotides, for which many recent studies have demonstrated a function in regulating gene expression, cell biology and carcinogenesis. Deregulated expression levels of lncRNAs have been observed in various types of cancers including hematological malignancies. The involvement of lncRNAs in cancer initiation and progression and their attractive features both as biomarker and for therapeutic research are becoming increasingly evident. In this review, we summarize the recent literature to highlight the status of the knowledge of lncRNAs role in normal B-cell development and in the pathogenesis of B-cell tumors.

Plasma Viral miRNAs Indicate a High Prevalence of Occult Viral Infections

Prevalence of Kaposi sarcoma-associated herpesvirus (KSHV/HHV-8) varies greatly in different populations. We hypothesized that the actual prevalence of KSHV/HHV8 infection in humans is underestimated by the currently available serological tests. We analyzed four independent patient cohorts with post-surgical or post-chemotherapy sepsis, chronic lymphocytic leukemia and post-surgical patients with abdominal surgical interventions. Levels of specific KSHV-encoded miRNAs were measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and KSHV/HHV-8 IgG were measured by immunoassay. We also measured specific miRNAs from Epstein Barr Virus (EBV), a virus closely related to KSHV/HHV-8, and determined the EBV serological status by ELISA for Epstein-Barr nuclear antigen 1 (EBNA-1) IgG. Finally, we identified the viral miRNAs by in situ hybridization (ISH) in bone marrow cells. In training/validation settings using independent multi-institutional cohorts of 300 plasma samples, we identified in 78.50% of the samples detectable expression of at least one of the three tested KSHV-miRNAs by RT-qPCR, while only 27.57% of samples were found to be seropositive for KSHV/HHV-8 IgG (P < 0.001). The prevalence of KSHV infection based on miRNAs qPCR is significantly higher than the prevalence determined by seropositivity, and this is more obvious for immuno-depressed patients. Plasma viral miRNAs quantification proved that EBV infection is ubiquitous. Measurement of viral miRNAs by qPCR has the potential to become the “gold” standard method to detect certain viral infections in clinical practice.

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There is no agreement on a standard assay to detect the true prevalence of Kaposi sarcoma-associated herpesvirus (KSHV) infection.

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Measurement of the viral miRNAs in plasma by RT-qPCR allows a direct and accurate assessment of viral infection.

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Measurement of the viral miRNAs in plasma by RT-qPCR shows prevalence of KSHV infection in immuno-depressed patients.

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Measurement of plasma viral miRNAs for viral infection assessment has the potential to become a “gold” standard method in the clinical practice.

Chronic viral infections represent risk factors for diseases and development of infection-related complications. There is no agreement on a standard assay to detect the true prevalence of Kaposi sarcoma-associated herpesvirus (KSHV) infection. The current method used in the clinical practice (ELISA-test) identifies a great geographic variation in KSHV seroprevalence and may underestimate the true-prevalence of KSHV infection. Here we showed that detection of plasma viral miRNAs levels for the identification of viral infection (e.g., KSHV, Epstein-Bar virus or EBV) is more accurate than the current method for detection of virus-derived antigen, especially in patients with low number of immune cells.

Cell-Cycle-Targeting MicroRNAs as Therapeutic Tools against Refractory Cancers

Cyclins and cyclin-dependent kinases (CDKs) are hyperactivated in numerous human tumors. To identify means of interfering with cyclins/CDKs, we performed nine genome-wide screens for human microRNAs (miRNAs) directly regulating cell-cycle proteins. We uncovered a distinct class of miRNAs that target nearly all cyclins/CDKs, which are very effective in inhibiting cancer cell proliferation. By profiling the response of over 120 human cancer cell lines, we derived an expression-based algorithm that can predict the response of tumors to cell-cycle-targeting miRNAs. Using systemic administration of nanoparticle-formulated miRNAs, we inhibited tumor progression in seven mouse xenograft models, including three treatment-refractory patient-derived tumors, without affecting normal tissues. Our results highlight the utility of using cell-cycle-targeting miRNAs for treatment of refractory cancer types.

Chronic lymphocytic leukemia: A prognostic model comprising only two biomarkers (IGHV mutational status and FISH cytogenetics) separates patients with different outcome and simplifies the CLL-IPI

Rai and Binet staging systems are important to predict the outcome of patients with chronic lymphocytic leukemia (CLL) but do not reflect the biologic diversity of the disease nor predict response to therapy, which ultimately shape patients' outcome. We devised a biomarkers-only CLL prognostic system based on the two most important prognostic parameters in CLL (i.e., IGHV mutational status and fluorescence in situ hybridization [FISH] cytogenetics), separating three different risk groups: (1) low-risk (mutated IGHV + no adverse FISH cytogenetics [del(17p), del(11q)]); (2) intermediate-risk (either unmutated IGHV or adverse FISH cytogenetics) and (3) high-risk (unmutated IGHV + adverse FISH cytogenetics). In 524 unselected subjects with CLL, the 10-year overall survival was 82% (95% CI 76%-88%), 52% (45%-62%), and 27% (17%-42%) for the low-, intermediate-, and high-risk groups, respectively. Patients with low-risk comprised around 50% of the series and had a life expectancy comparable to the general population. The prognostic model was fully validated in two independent cohorts, including 417 patients representative of general CLL population and 337 patients with Binet stage A CLL. The model had a similar discriminatory value as the CLL-IPI. Moreover, it applied to all patients with CLL independently of age, and separated patients with different risk within Rai or Binet clinical stages. The biomarkers-only CLL prognostic system presented here simplifies the CLL-IPI and could be useful in daily practice and to stratify patients in clinical trials.

Exosomes and Exosomal MicroRNAs in Prostate Cancer Radiation Therapy

Despite current risk stratification systems using traditional clinicopathologic factors, many localized and locally advanced prostate cancers fail radical treatment (ie, radical prostatectomy, radiation therapy with or without androgen deprivation therapy). Therefore, a pressing need exists for enhanced methods of disease stratification through novel prognostic and predictive tools that can reliably be applied in clinical practice. Exosomes are 50- to 150-nm small vesicles released by cancer cells that reflect the genetic and nongenetic materials of parent cancer cells. Cancer cells can contain distinct sets of microRNA profiles, the expression of which can change owing to stress such as radiation therapy. These alterations or distinctions in contents allow exosomes to be used as prognostic and/or predictive biomarkers and to monitor the treatment response. Additionally, microRNAs have been shown to influence multiple processes in prostate tumorigenesis, including cell proliferation, induction of apoptosis, migration, oncogene inhibition, and radioresistance. Thus, comparative exosomal microRNA profiling at different levels could help portray tumor aggressiveness and response to radiation therapy. Although technical challenges persist in exosome isolation and characterization, recent improvements in microRNA profiling have evolved toward in-depth analyses of the exosomal cargo and its functions. We have reviewed the role of exosomes and exosomal microRNAs in biologic processes of prostate cancer progression and radiation therapy response, with a particular focus on the development of clinical assays for treatment personalization.