Functional genomics of tumor suppressor miR-196b in T-cell acute lymphoblastic leukemia

MicroRNAs and the Diagnosis of Childhood Acute Lymphoblastic Leukemia: Systematic Review, Meta-Analysis and Re-Analysis with Novel Small RNA-Seq Tools

Simple Summary

MicroRNAs (miRNAs) have been under the spotlight for the last three decades. These non-coding RNAs seem to be dynamic regulators of mRNA stability and translation, in addition to interfering with transcription. Circulating miRNAs play a critical role in cell-to-cell interplay; therefore, they can serve as disease biomarkers. Meta-analysis of published data revealed that the CC genotype of rs4938723 in pri-miR-34b/c and the TT genotype of rs543412 in miR-100 confer protection against acute lymphoblastic leukemia (ALL) in children. Reanalysis of small RNA-seq data with novel tools identified significantly overexpressed members of the miR-128, miR-181, miR-130 and miR-17 families and significantly lower expression of miR-30, miR-24-2 and miR143~145 clusters, miR-574 and miR-618 in pediatric T-ALL cases compared with controls. Inconsistencies in methodology and study designs in most published material preclude reproducibility, and further cohort studies need to be conducted in order to empower novel tools, such as ALLSorts and RNAseqCNV.

Abstract

MicroRNAs (miRNAs) have been implicated in childhood acute lymphoblastic leukemia (ALL) pathogenesis. We performed a systematic review and meta-analysis of miRNA single-nucleotide polymorphisms (SNPs) in childhood ALL compared with healthy children, which revealed (i) that the CC genotype of rs4938723 in pri-miR-34b/c and the TT genotype of rs543412 in miR-100 confer protection against ALL occurrence in children; (ii) no significant association between rs2910164 genotypes in miR-146a and childhood ALL; and (iii) SNPs in DROSHA, miR-449b, miR-938, miR-3117 and miR-3689d-2 genes seem to be associated with susceptibility to B-ALL in childhood. A review of published literature on differential expression of miRNAs in children with ALL compared with controls revealed a significant upregulation of the miR-128 family, miR-130b, miR-155, miR-181 family, miR-210, miR-222, miR-363 and miR-708, along with significant downregulation of miR-143 and miR-148a, seem to have a definite role in childhood ALL development. MicroRNA signatures among childhood ALL subtypes, along with differential miRNA expression patterns between B-ALL and T-ALL cases, were scrutinized. With respect to T-ALL pediatric cases, we reanalyzed RNA-seq datasets with a robust and sensitive pipeline and confirmed the significant differential expression of hsa-miR-16-5p, hsa-miR-19b-3p, hsa-miR-92a-2-5p, hsa-miR-128-3p (ranked first), hsa-miR-130b-3p and -5p, hsa-miR-181a-5p, -2-3p and -3p, hsa-miR-181b-5p and -3p, hsa-miR-145-5p and hsa-miR-574-3p, as described in the literature, along with novel identified miRNAs.

Mechanism of Human Telomerase Reverse Transcriptase (hTERT) Regulation and Clinical Impacts in Leukemia

The proliferative capacity and continuous survival of cells are highly dependent on telomerase expression and the maintenance of telomere length. For this reason, elevated expression of telomerase has been identified in virtually all cancers, including leukemias; however, it should be noted that expression of telomerase is sometimes observed later in malignant development. This time point of activation is highly dependent on the type of leukemia and its causative factors. Many recent studies in this field have contributed to the elucidation of the mechanisms by which the various forms of leukemias increase telomerase activity. These include the dysregulation of telomerase reverse transcriptase (TERT) at various levels which include transcriptional, post-transcriptional, and post-translational stages. The pathways and biological molecules involved in these processes are also being deciphered with the advent of enabling technologies such as next-generation sequencing (NGS), ribonucleic acid sequencing (RNA-Seq), liquid chromatography-mass spectrometry (LCMS/MS), and many others. It has also been established that TERT possess diagnostic value as most adult cells do not express high levels of telomerase. Indeed, studies have shown that prognosis is not favorable in patients who have leukemias expressing high levels of telomerase. Recent research has indicated that targeting of this gene is able to control the survival of malignant cells and therefore offers a potential treatment for TERT-dependent leukemias. Here we review the mechanisms of hTERT regulation and deliberate their association in malignant states of leukemic cells. Further, we also cover the clinical implications of this gene including its use in diagnostic, prognostic, and therapeutic discoveries.

Could MicroRNAs Be Useful Tools to Improve the Diagnosis and Treatment of Rare Gynecological Cancers? A Brief Overview

Gynecological cancers pose an important public health issue, with a high incidence among women of all ages. Gynecological cancers such as malignant germ-cell tumors, sex-cord-stromal tumors, uterine sarcomas and carcinosarcomas, gestational trophoblastic neoplasia, vulvar carcinoma and melanoma of the female genital tract, are defined as rare with an annual incidence of <6 per 100,000 women. Rare gynecological cancers (RGCs) are associated with poor prognosis, and given the low incidence of each entity, there is the risk of delayed diagnosis due to clinical inexperience and limited therapeutic options. There has been a growing interest in the field of microRNAs (miRNAs), a class of small non-coding RNAs of ∼22 nucleotides in length, because of their potential to regulate diverse biological processes. miRNAs usually induce mRNA degradation and translational repression by interacting with the 3' untranslated region (3'-UTR) of target mRNAs, as well as other regions and gene promoters, as well as activating translation or regulating transcription under certain conditions. Recent research has revealed the enormous promise of miRNAs for improving the diagnosis, therapy and prognosis of all major gynecological cancers. However, to date, only a few studies have been performed on RGCs. In this review, we summarize the data currently available regarding RGCs.

Role of microRNA dysregulation in childhood acute leukemias: Diagnostics, monitoring and therapeutics: A comprehensive review

MicroRNAs (miRNAs) are short noncoding RNAs that regulate the expression of genes by sequence-specific binding to mRNA to either promote or block its translation; they can also act as tumor suppressors (e.g., let-7b, miR-29a, miR-99, mir-100, miR-155, and miR-181) and/or oncogenes (e.g., miR-29a, miR-125b, miR-143-p3, mir-155, miR-181, miR-183, miR-196b, and miR-223) in childhood acute leukemia (AL). Differentially expressed miRNAs are important factors associated with the initiation and progression of AL. As shown in many studies, they can be used as noninvasive diagnostic and prognostic biomarkers, which are useful in monitoring early stages of AL development or during therapy (e.g., miR-125b, miR-146b, miR-181c, and miR-4786), accurate classification of different cellular or molecular AL subgroups (e.g., let-7b, miR-98, miR-100, miR-128b, and miR-223), and identification and development of new therapeutic agents (e.g., mir-10, miR-125b, miR-203, miR-210, miR-335). Specific miRNA patterns have also been described for commonly used AL therapy drugs (e.g., miR-125b and miR-223 for doxorubicin, miR-335 and miR-1208 for prednisolone, and miR-203 for imatinib), uncovering miRNAs that are associated with treatment response. In the current review, the role of miRNAs in the development, progression, and therapy monitoring of pediatric ALs will be presented and discussed.

miRNA deregulation in childhood acute lymphoblastic leukemia: a systematic review

Despite remarkable improvements in survival of childhood acute lymphoblastic leukemia (ALL), nonresponding or relapsing patients still represent one of the most frequent causes of death by disease in children. Accurate patient risk stratification based on genetic markers could increases survival rates. miRNAs can represent novel candidates with diagnostic, predictive and prognostic potential; however, many groups investigated their involvement with contradictory results. Aim: To clarify the role of miRNAs as biomarkers through a systematic review. Results: From a revision of 45 manuscripts, we found that miR-128 and miR-181 overexpression could represent markers for ALL diagnosis and underexpression of miR-708 and miR-99a could be markers for bad prognosis. Conclusion: These signatures could refine classification and risk stratification of patients and improve ALL outcome.

The role of microRNAs in acute lymphoblastic leukaemia: From biology to applications

MicroRNAs (miRNAs) that are characterized by small, noncoding RNA have an essential role in the pathogenesis of human diseases, including cancer. Furthermore, miRNAs, as a new paradigm of epigenetic regulators, play an important role in normal development and cellular function. This literature review summarizes the recurrent mechanism of gene regulation through miRNAs and, consequently, the impact of regulated genes on different cellular processes, including proliferation, metastasis, prognosis, and apoptosis. Additionally, what is important to note is that the expression of miRNAs in various cancer cells is different, and miRNAs have various target genes in various cancers. Accordingly, a proper understanding of gene regulation by miRNAs contributes to new perspectives in miRNA-based therapeutic strategies. SIGNIFICANCE OF THE STUDY: MiRNAs are considered as a crucial regulator of gene expression. The genes also play an important role in the expression of miRNAs; as a result, there is a relationship between them. In recent years, targeted therapy with miRNAs has been a significant challenge. Studying the mechanisms through which miRNAs regulate various cancer cell processes, including apoptosis, proliferation, and metastasis, is very critical in the treatment of cancer through miRNAs. Definitely, a proper understanding of the impacts of aberrant expression of miRNAs on cancer cell processes leads to new therapeutic strategies in the targeted therapy with miRNAs.

MicroRNAs and their involvement in T-ALL: A brief overview

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy in which the transformed clone is arrested during T-cell development. Several genetic and epigenetic events have been implicated in this transformation. MicroRNAs (miRNAs) are small, non-coding RNAs that primarily function as endogenous translational repressors of protein-coding genes. The involvement of miRNAs in the regulation of cancer progression is well-established, namely by down-regulating the expression of key oncogenes or tumor suppressors and thereby preventing or promoting tumorigenesis, respectively. Similar to other cancers, several miRNA genes have been identified and implicated in the context of T-ALL. In this review we focused on the most studied microRNAs associated with T-ALL pathogenesis.

miR-196b inhibits cell migration and invasion through targeting MAP3K1 in hydatidiform mole

MicroRNAs (miRNAs) are a class of small non-coding RNAs that are closely associated with carcinogenesis. Accumulating data indicate that miR-196b participates in the development of various types of cancers. However, the role of miR-196b in the formation of hydatidiform mole (HM) is still unclear. Our previous studies have demonstrated that miR-196b levels were decreased in JAR and BeWo cells and in HM tissue samples, as demonstrated by RT-PCR analysis. Furthermore, we discovered that overexpression of miR-196b in JAR and BeWo cells inhibited cellular proliferation, migration and invasion, as shown by Cell counting kit-8 (CCK-8) and transwell assays, respectively. Subsequently, we explored the interaction of miR-196b with its target gene in human choriocarcinoma cell lines. MAP3K1 is a target gene predicted by bioinformatic analysis that was previously shown to exhibit reduced expression levels following treatment with miR-196b in JAR and BeWo cells. We demonstrated that MAP3K1 was a direct target of miR-196b using the dual-luciferase reporter assay in Hela cells. In summary, the present study demonstrated that miR-196b suppressed proliferation, migration and invasion of human choriocarcinoma cells by inhibiting its transcriptional target MAP3K1. miR-196b and MAP3K1 may be considered potential targets for the clinical treatment of HM.

Prognostic miRNA classifiers in t cell acute lymphoblastic leukemia: Study protocol for a systematic review and meta-analysis of observational clinical studies

BACKGROUND

The prognostic value of microRNA (miRNA) expression in T-cell acute lymphoblastic leukemia (T-ALL) has generated significant research interest in recent years. However, most diagnostic and prognostic studies with regards to miRNA expression have been focused on combined B cell and T cell lymphoblastic leukemia. There are very few studies reporting the prognostic effects of miRNA expression on T-ALL. Therefore, a pioneer systematic review and meta-analysis was proposed to explore the possibilities of miRNAs as viable prognostic markers in T-ALL. This study is intended to be useful as a guideline for future research into drug evaluation and targeting miRNA as a biomarker for the treatment and prognosis of T-ALL.

METHODS

The systematic review will be reported according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. The study search will be conducted by using Cochrane, EMBASE, Medline, Science Direct, and SCOPUS bibliographic databases. The reference lists of included studies will be manually searched to further bolster the search results. A combination of keywords will be used to search the databases.

DISCUSSION

To explore the effect of miRNA on prognosis, forest plots will be generated to assess pooled HR and 95% CI. Upregulation, downregulation, and deregulation of specific miRNAs will be individually noted and used to extrapolate patient prognosis when associated with risk factors involved in T-ALL. Subgroup analysis will be carried out to analyze the effect of deregulation of miRNA expression on patient prognosis. A fixed or random-effects model of meta-analysis will be used depending upon between-study heterogeneity. This systematic review and meta-analysis will identify and synthesize evidence to determine the prognosis of miRNA in T-ALL and suggest the possible miRNA from meta-analysis results to predict as a biomarker for further detection and treatment of T-ALL.

Prognostic impact of miR-196a/b expression in adult acute myeloid leukaemia: a single-centre, retrospective cohort study

Objective

The prognostic effect of miR-196a/b expression in adult patients with leukaemia remains unclear. This study aimed to determine whether miR-196a/b expression can serve as a prognostic factor for patients with acute myeloid leukaemia.

Methods

We enrolled 124 patients with acute myeloid leukaemia. We measured miR-196a/b expression by real-time reverse transcription-polymerase chain reaction. We classified patients into high and low expression groups based on the median expression value. Cox regression analyses were carried out to assess the prognostic significance of miR-196a/b expression in the context of well-established predictors.

Results

Patients with high miR-196a/b expression were older in age, and had higher white blood cell and platelet counts than did patients with low miR-196a/b expression. Patients with high miR-196a/b expression were associated with the French–American–British classification M5 subtype and with the presence of nucleophosmin and FLT3 internal tandem duplication mutations, but were not associated with the favourable karyotype risk subgroup. Moreover, patients with high miR-196a/b expression had a shorter event-free survival rate compared with those with low miR-196a/b expression in univariate and multivariate analyses.

Conclusion

High miR-196a/b expression is associated with poor event-free survival.

MicroRNA-196b enhances the radiosensitivity of SNU-638 gastric cancer cells by targeting RAD23B

Gastric cancer is characterized by resistance to ionizing radiation. The development of resistance to radiotherapy in gastric cancer patients is one of the obstacles to effective radiotherapy. MicroRNAs are small well-conserved non-coding RNA species that regulate post-transcriptional activation. Our study aimed to investigate the role of miR-196b in radiation-induced gastric cancer. In the present study, we found that miR-196b expression was significantly reduced following radiation. The ectopic miR-196b expression sensitized SNU-638 gastric cancer cells and increased γ-H2AX foci upon radiation treatment. Bioinformatics analysis suggested that the DNA repair protein RAD23B was a putative target gene of miR-196b. Overexpression of miR-196b suppressed RAD23B expression in SNU-638 cells. Reporter assays further showed that miR-196b inhibited RAD23B 3'-UTR luciferase activity. Knockdown of RAD23B by small interfering RNA transfection closely mimicked the outcomes of miR-196b transfection, leading to impaired DNA damage repair in gastric cancer cells. Our results show that miR-196b improved radiosensitivity of SNU-638 cells by targeting RAD23B. Our data indicate that miR-196b is a potential target to enhance the effect of radiation treatment on gastric cancer cells. These findings will provide evidence for a new therapeutic target in radiotherapy.

T-cell acute lymphoblastic leukemia from miRNA perspective: Basic concepts, experimental approaches, and potential biomarkers

T-cell acute lymphoblastic leukemia (T-ALL) is a rare, aggressive and heterogeneous malignancy originating from T-cell precursors. The mechanisms of T-ALL pathogenesis related to non-protein coding part of the genome are currently intensively studied. miRNAs are short, non-coding molecules acting as negative regulators of gene expression which shape phenotype of cells in a complex and context-specific manner. miRNAs may act as oncogenes or tumor suppressors; several miRNAs have been related to drug resistance and treatment response in various malignancies. Here we present the review of the state-of-the-art knowledge on the role of miRNAs in T-ALL pathogenesis, with detailed overview of the studies reporting on miRNAs with oncogenic and tumor suppressor potential. We discuss whether miRNAs might be considered candidate biomarkers of prognosis in T-ALL and leukemia subtype-specific markers. We also describe experimental approaches and a typical workflow applied in research on the involvement of miRNAs in oncogenesis.

Circulating microRNA124-3p, microRNA9-3p and microRNA196b-5p may be potential signatures for differential diagnosis of thyroid nodules

It is important to develop an effective auxiliary approach to distinguish papillary thyroid carcinoma (PTC) from benign nodules because a considerable proportion cannot be identified by fine-needle aspiration cytology at present, resulting in unnecessary thyroidectomy. Circulating miRNAs are potential biomarkers for differential diagnosis of tumors. We aimed to investigate the dysregulation of circulating miRNAs in PTC and evaluate the diagnostic value for differentiation of PTC from benign nodules. We first assessed the expression of miRNAs in patients with PTC, patients with benign nodules and healthy controls using a miRCURY LNA Array (n = 3 for each group). Expression of circulating miR-124-3p, miR-9-3p and miR-5691 was significantly up-regulated, while miR-4701 and miR-196b-5p were down-regulated in PTC patients. The dysregulation of miR-124-3p, miR-9-3p, miR-4701 and miR-196b-5p was further validated by qRT-PCR in fifty participants from each group. The expression of circulating miR-124-3p and miR-9-3p was significantly up-regulated in PTC patients. Both miR-124-3p and miR-9-3p could distinguish PTC from benign nodules with high sensitivity and specificity. There were no significant differences in the expression of circulating miR-4701 and miR-196b-5p between PTC patients and healthy controls. Nevertheless, patients with benign nodules showed a higher level of miR-196b-5p compared with that of PTC patients and healthy controls. ROC analysis indicated that miR-196b-5p had a good diagnostic value for differentiation of benign nodules from PTC. Our study suggested that miR-124-3p, miR-9-3p and miR-196b-5p may be potential signatures for differential diagnosis of thyroid nodules in eastern coastal areas of China.

Dysregulation of Mir-196b in Head and Neck Cancers Leads to Pleiotropic Effects in the Tumor Cells and Surrounding Stromal Fibroblasts

The miR-196 family members have been found dysregulated in different cancers. Therefore, they have been proposed as promising biomarkers and therapeutic targets. This study is the first to investigate the role of miR-196b in the development and progression of head and neck squamous cell carcinomas (HNSCC), and also the impact on the surrounding tumor microenvironment. Increased miR-196b levels were detected in 95% of primary tumors and precancerous lesions, although no significant differences were observed between non-progressing versus progressing dysplasias. Furthermore, increased levels of both miR-196a and miR-196b were successfully detected in saliva samples from HNSCC patients. The functional consequences of altered miR-196 expression were investigated in both HNSCC cell lines and cancer-associated fibroblasts (CAFs) by transfection with specific pre-miR precursors. Results showed that both miR-196a and miR-196b elicit cell-specific responses in target genes and downstream regulatory pathways, and have a distinctive impact on cell proliferation, migration and invasion. These data reveal the early occurrence and prevalence of miR-196b dysregulation in HNSCC tumorigenesis, suggesting its utility for early diagnosis and/or disease surveillance and also as a non-invasive biomarker in saliva. The pleiotropic effects of miR-196a/b in HNSCC cell subpopulations and surrounding CAFs may complicate a possible therapeutic application.

Aberrant DNA hypomethylation of miR-196b contributes to migration and invasion of oral cancer

MicroRNAs (miRs) are a class of small endogenous non-coding RNAs of ~21-24 nucleotides in length. Previous studies have indicated that miR-196b has either an oncogenic or tumor-suppressive function in various types of cancer. However, the biological role of miR-196b in oral squamous cell carcinoma (OSCC) remains unclear. In the present study, the expression levels of miR-196b were examined in oral cancer tissues and corresponding adjacent normal tissues from 69 OSCC patients using stem-loop reverse transcription-quantitative polymerase chain reaction. The results indicated that miR-196b was significantly overexpressed in OSCC tissues compared with the corresponding adjacent normal tissue samples (64 of 69, 92.7%, P<0.001). Analysis of the methylation status of the miR-196b gene indicated more frequent hypomethylation of the CpG islands located upstream of the miR-196b gene in the OSCC tissues than in the adjacent normal tissues (32 of 69, 46.3%), and the methylation status of miR-196b correlated inversely with its expression levels. Furthermore, the unmethylated status of the miR-196b promoter correlated with poor disease-specific survival in OSCC patients (P=0.035). Functional analysis revealed that ectopic miR-196b expression promoted oral cancer cell migration and invasion abilities, and that silencing of miR-196b could abrogate in vitro migration and invasion of oral cancer cells. Collectively, the present findings indicate that the epigenetic regulation of miR-196b expression plays a crucial role in modulating cell migration and invasion during OSCC progression, and thus may serve as a potential prognosis marker or therapeutic target for OSCC.

Specific microRNAs as novel biomarkers for combination chemotherapy resistance detection of colon adenocarcinoma

Background and objectives

Colon cancer is a frequently occurring primary malignant tumor. Chemotherapy can reduce the risk of local and distant relapse. Therefore, it is very important to find new biomarkers that can predict chemoresistance and help in individuate treatment decision.

Design and setting

Retrospective analysis of 126 patients, who were treated at our department between June 2010 and December 2014.

Patients and methods

In this study, we examined the expression levels of 1200 human miRNAs in colon cancer tissues, using laser capture microdissection and microRNA profiling arrays. A validation study was done to corroborate a subset of the results, including expression levels of miR-4299, miR-196b, miR-324-5p, miR-455-3p and miR-939, through analyzing stage IV colon adenocarcinoma tissues (not responding and responding to the chemotherapy) with laser capture microdissection and quantitative real-time PCR. We analyze the relationship between the expression levels of these miRNAs and the survival rate of colon cancer patients by Kaplan–Meier method.

Results

We found that miR-4299 and -196b have significant diagnostic value in chemoresistant colon cancer. MiR-4299 yielded an AUC (the areas under the ROC curve) of 0.810 and miR-196b yielded an AUC of 0.726 in discriminating chemoresistant colon cancer from controls. Combined with ROC analyses of these 2 miRNAs revealed an elevated AUC of 0.877 with 71.4 % sensitivity and 95.5 % specificity in discriminating chemoresistant colon cancer. The low level of miR-4299 expression and the high level of -196b expression are significantly correlated with better survival of colon cancer patients.

Discussion

These data suggest that miR-4299 and -196b have strong potential as novel biomarkers for chemoresistance detection of colon cancer.

MicroRNA 196B regulates FAS-mediated apoptosis in colorectal cancer cells

Using miRNA microarray analysis, we identified 31 miRNAs that were significantly up-regulated or down-regulated in colon cancer tissues. We chose MIR196B, which was specifically up-regulated in colon cancer, for further study. We identified 18 putative MIR196B target genes by comparing between the mRNAs down-regulated in MIR196B-overexpressed cells and the assumed MIR196B target genes predicted by public bioinformatics tools. The association between MIR196B and FAS was verified in this study. FAS expression was constitutively elevated in normal human colorectal tissues. However, its expression was often reduced in human colorectal cancer. The decrease in FAS expression could be responsible for the reduction of apoptosis in colorectal cancer cells. In colorectal cancer tissue, we showed that MIR196B up-regulation was mutually followed by down regulation of FAS expression. We also showed that MIR196B directly repressed FAS expression in colorectal cells. Furthermore, anti-MIR196B up-regulated FAS expression and increased apoptosis in colorectal cancer cell lines. Our results suggest that the up-regulation of MIR196B modulates apoptosis in colorectal cancer cells by partially repressing FAS expression and that anti-MIR196B could be a potential candidate as an anti-cancer drug in colorectal cancer therapy.

The functional role of microRNA in acute lymphoblastic leukemia: relevance for diagnosis, differential diagnosis, prognosis, and therapy

MicroRNAs (miRNAs), a new class of noncoding RNAs, which can hybridize to target messenger RNAs and regulate their expression posttranscriptionally, express differentially in distinct stages of lymphopoiesis and influence the direction of lymphoid precursor maturation. Hence, there is aberrant expression of miRNAs involved in malignant lymphopoiesis, and these aberrations can be used as signatures of acute lymphoblastic leukemia (ALL) with different subtypes. In addition, changes in the expression of several miRNAs may have functional relevance with leukemogenesis or drug resistance. As a result, the reversal of the expression of these miRNAs may alleviate the disease to some extent and improve clinical outcomes. However, among the studies of miRNAs, there are still some problems that need to be solved to understand the function of miRNAs in ALL more thoroughly.

MicroRNA expression profile in colorectal cancer

AIM: To examine the expression of microRNAs (miRNAs) in colorectal cancer (CRC) and adjacent tissues by miRNA gene microarray, determine some cellular functions and molecular pathways targeted by these differentially expressed miRNAs, and discuss the clinical significance of differential miRNA expression profile in CRC.

METHODS: Surgical CRC and adjacent tissues were collected from 11 CRC patients and frozen immediately. For microarray analysis, the AFFX miRNA biochip was used. Total RNA was isolated from samples and expression of miRNAs was analyzed. Of the screened differentially expressed miRNAs, miR-31, miR-105 and miR-196b, which were strongly up-regulated in CRC, were selected for validation by real-time PCR using 53 CRC and 15 adjacent tissues. The relationships between the differential expression of these miRNAs and clinical and pathological characteristics were analyzed.

RESULTS: MiRNA expression in CRC and adjacent normal tissues had obvious differences. A total of 25 miRNAs that were significantly differentially expressed in CRC were screened (P < 0.001), of which 15 were up-regulated and 10 down-regulated. MiR-31 expression was significantly correlated with CRC pathological type (P < 0.01) and clinical stage (P < 0.05), but not with lymph node metastasis or distant metastasis (P > 0.05). MiR-105 was positively correlated with pathologic classification, clinical stage, lymph node metastasis and distant metastasis (P < 0.05). MiR-196b was significantly correlated with pathological classification (P < 0.05), but not with lymph node metastasis, distant metastasis or clinical stage (P > 0.05).

CONCLUSION: Differentially expressed miRNAs exist in CRC, and these miRNAs may become potential molecular targets for diagnosis and treatment of CRC. High expression of miR-31, miR-105 and miR-196b is related to the pathological classification of CRC.

OncomiR-196 promotes an invasive phenotype in oral cancer through the NME4-JNK-TIMP1-MMP signaling pathway

Background

MicroRNA-196 (miR-196), which is highly up-regulated in oral cancer cells, has been reported to be aberrantly expressed in several cancers; however, the significance of miR-196 in oral cancer has not yet been addressed.

Methods

Cellular functions in response to miR-196 modulation were examined, including cell growth, migration, invasion and radio/chemosensitivity. Algorithm-based studies were used to identify the regulatory target of miR-196. The miR-196 target gene and downstream molecular mechanisms were confirmed by RT-qPCR, western blot, luciferase reporter and confocal microscopy analyses. miR-196 expression was determined in paired cancer and adjacent normal tissues from oral cancer patients.

Results

Both miR-196a and miR-196b were highly over-expressed in the cancer tissue and correlated with lymph node metastasis (P = 0.001 and P = 0.006, respectively). Functionally, miR-196 actively promoted cell migration and invasion without affecting cell growth. Mechanistically, miR-196 performed it's their function by inhibiting NME4 expression and further activating p-JNK, suppressing TIMP1, and augmenting MMP1/9.

Conclusion

miR-196 contributes to oral cancer by promoting cell migration and invasion. Clinically, miR-196a/b was significantly over-expressed in the cancer tissues and correlated with lymph node metastasis. Thus, our findings provide new knowledge of the underlying mechanism of cancer metastasis. miR-196 may serve as a promising marker for better oral cancer management.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-4598-13-218) contains supplementary material, which is available to authorized users.

miR-449a and CDK6 in gastric carcinoma

The present study aimed to identify the association between microRNA (miR/miRNA)-449a, the cyclin-dependent kinase (CDK)6 protein and gastric carcinoma, and discuss the effect of miR-449a on the expression of the CDK6 protein. Quantitative (q)PCR and western blot analysis were used to analyze the expression of the miR-449a and the CDK6 protein in gastric carcinoma and tumor-adjacent normal tissues. The real-time cell analyzer and the DAPI staining test were used to monitor the different miR-449a levels regulating the proliferation and apoptosis of the MGC-803 cell line. Immunofluorescence and western blot analyses were used to detect the expression level of the CDK6 protein in the cells of the miR-449a upregulation and downregulation groups, and a control group. A scratch test was used to study the effects of miR-449a expression on migration and invasion. It was found that the expression of miR-449a was downregulated and the expression of CDK6 protein was upregulated in gastric carcinoma tissue. The level of MGC-803 cell proliferation was decreased and the apoptosis level was increased by the upregulation of miR-449a expression, and the opposite effect was shown by the downregulation of expression. The expression of the CDK6 protein in the MGC-803 cells was downregulated by upregulating the expression of miR-449a. The distance of the scratch was shortened markedly after 12 h by downregulating the expression of miR-449a in the MGC-803 cells. The present study identified that a lower expression level of miR-449 and a higher expression level of CDK6 may contribute to the occurrence and development of gastric cancer. Furthermore, it was shown that miR-449a is able to regulate the expression of the CDK6 protein.

Targeted therapy in gastric cancer: personalizing cancer treatment based on patient genome

Gastric cancer is the second leading cause of cancer-related deaths worldwide. Conventional cytotoxic chemotherapy has limited efficacy for metastatic gastric cancer, with an overall survival of approximately ten months. Recent advances in high-throughput technologies have enabled the implementation of personalized cancer therapy for high-risk patients. The use of such high-throughput technologies, including microarray and next generation sequencing, have promoted the discovery of novel targets that offer new treatment strategies for patients lacking other therapeutic options. Many molecular pathways are currently under investigation as therapeutic targets in gastric cancer, including those related to the epidermal growth factor receptor family, the mesenchymal-epithelial transition factor axis, and the phosphatidylinositol 3-kinase-AKT-mammalian target of rapamycin factors. Advances in molecular diagnostic tools further support the discovery of new molecular targets. Limitations exist, however; not all patients can be tested for biomarkers, and numerous challenges hamper implementation of targeted therapy in clinical settings. Indeed, the scale of tumor genomic profiling is rapidly outpacing our ability to appropriately synthesize all the information in order to optimally refine patient care. Therefore, clinicians must continue to educate themselves regarding new tools and frameworks, and to utilize multidisciplinary team science, comprised of oncologists, geneticists, pathologists, biologists and bioinformaticians, to successfully implement this genomic approach therapeutically.

Overexpression of miR-196b and HOXA10 characterize a poor-prognosis gastric cancer subtype

AIM: To identify molecular biologic differences between two gastric adenocarcinoma subgroups presenting different prognoses through the analysis of microRNA and protein expression.

METHODS: Array technologies were used to generate 1146 microRNAs and 124 proteins expression profiles of samples from 60 patients with gastric cancer. For the integrative analysis, we used established mRNA expression data published in our previous study. Whole mRNA expression levels were acquired from microarray data for 60 identical gastric cancer patients. Two gastric adenocarcinoma subgroups with distinct mRNA expression profiles presented distinctly different prognoses. MicroRNA and protein expression patterns were compared between gastric cancer tissue and normal gastric tissue and between two different prognostic groups. Aberrantly expressed microRNA, associated mRNA, and protein in patients with poor-prognosis gastric cancer were validated by quantitative reverse transcription polymerase chain reaction and immunochemistry in independent patients.

RESULTS: We obtained the expression data of 1146 microRNAs and 124 cancer-related proteins. Four microRNAs were aberrantly expressed in the two prognostic groups and in cancer vs non-cancer tissues (P < 0.05). In the poor-prognosis group, miR-196b, miR-135b, and miR-93 were up-regulated and miR-29c* was down-regulated. miR-196b expression positively correlated with Homeobox A10 (HOXA10) expression (r = 0.726, P < 0.001), which was significantly increased in poor-prognosis patients (P < 0.001). Comparing gastric cancer with non-cancer tissues, 46/124 proteins showed differential expression (P < 0.05); COX2 (P < 0.001) and cyclin B1 (P = 0.017) were clearly over-expressed in the poor-prognosis group.

CONCLUSION: Co-activation of miR-196b and HOXA10 characterized a poor-prognosis subgroup of patients with gastric cancer. Elucidation of the biologic function of miR-196b and HOXA10 is warranted.

miR-196b targets c-myc and Bcl-2 expression, inhibits proliferation and induces apoptosis in endometriotic stromal cells

STUDY QUESTION

What is the global expression pattern of microRNAs (miRNAs) in endometriotic stromal cells and is miR-196b involved in the pathogenesis of endometriosis?

SUMMARY ANSWER

Several miRNAs are aberrantly expressed in endometriotic cyst stromal cells (ECSCs), including miR-196b whose expression is repressed in endometriotic stromal cells.

WHAT IS KNOWN ALREADY

Although, histologically, endometriotic tissues and normal proliferative endometrium are similar, a number of distinct molecular differences have been reported to date. The anti-apoptotic and excessive proliferative properties of endometriotic cells are considered to be involved in the development and progression of endometriosis.

STUDY DESIGN AND SIZE DURATION

ECSCs and normal endometrial stromal cells (NESCs) were isolated from ovarian endometriotic tissues and eutopic endometrial tissues, respectively and compared.

PARTICIPANTS/MATERIALS, SETTING AND METHODS

Aberrantly expressed miRNAs in ECSCs were identified by a global miRNA microarray technique. The roles of miR-196b in ECSC proliferation, apoptosis, and c-myc and B-cell lymphoma/leukemia (Bcl)-2 mRNA expression were investigated with precursor hsa-miR-196b transfection. The methylation status of the miR-196b gene in ECSCs and the effect of a DNA demethylating agent on miR-196b expression were also examined.

MAIN RESULTS AND THE ROLE OF CHANCE

miRNA microarray analysis identified eight down-regulated miRNAs (including miR-196b) and four up-regulated miRNAs in ECSCs. Compulsory expression of miR-196b directed the inhibition of proliferation and the induction of apoptosis in ECSCs. miR-196b was found to suppress c-myc and Bcl-2 mRNA expression in ECSCs, and there was a significant correlation between miR-196b and HOXA10 expression in ECSCs and NESCs. The miR-196b gene was hypermethylated in ECSCs when compared with NESCs, and the treatment with a DNA demethylating agent restored the expression of miR-196b in ECSCs.

LIMITATIONS AND REASONS FOR CAUTION

miRNA expression profiles were investigated only in the stromal component of ectopic and eutopic endometrium samples. In addition to miR-196b, the roles of other miRNAs aberrantly expressed in ECSCs should be examined.

WIDER IMPLICATIONS OF THE FINDINGS

The present findings suggest that aberrant miRNA expression plays an important role in the pathogenesis of endometriosis as a part of epigenetic mechanisms, that expression of miR-196b in ECSCs is repressed by DNA hypermethylation of the miR-196b gene and this repression may be involved in the development of proliferative and anti-apoptotic characteristics of endometriosis.

STUDY FUNDING

This work was supported in part by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (no. 20591920 to K.N. and no. 23592407 to H.N.) and The Uehara Memorial Foundation (to K.N.).

MicroRNA expression and activity in pediatric acute lymphoblastic leukemia (ALL)

Acute lymphoblastic leukemia (ALL) is the most common type of pediatric neoplasia. Highly heterogeneous, ALL includes several genetic subtypes with varying clinical outcome. Although, some features are well established as prognostic predictors, the details of the molecular mechanisms underlying different phenotypes are only beginning to emerge. Recently, microRNAs (miRNAs) have been shown to influence a range of physiological processes and, consequently, alterations in their expression and functions have been associated with the development of many cancers, including leukemia. This article aims to review the current state of knowledge of the role of miRNAs on the biology of childhood ALL, also including relevant findings from the adult leukemia literature.

Upregulation of miR-196b confers a poor prognosis in glioblastoma patients via inducing a proliferative phenotype

PURPOSE

To explore the expression pattern, prognostic value and functional role of miR-196b in glioblastoma (GBM) patients using large cohorts.

EXPERIMENTAL DESIGN

MiR-196b expression was measured using the Human v2.0 miRNA Expression BeadChip (Illumina) in 198 frozen glioma tissues. The expression levels of miR-196b were also validated in an independent cohort containing 128 formalin-fixed paraffin-embedded (FFPE) glioma samples using qRT-PCR. The presence of other molecular prognostic indicators was assessed centrally in the glioma samples. Whole genome gene profiling was performed to investigate the underlying biological behavior. MiR-196b functional analyses were performed in U87 and U251 cell lines.

RESULTS

The expression levels of miR-196b were inversely correlated with overall survival in GBM patients. Gene set enrichment analysis (GSEA) showed that the gene sets relating to cell cycle were significantly enriched in the cases with miR-196b overexpression. Functional analyses in U87 and U251 cells revealed that miR-196b was involved in cell proliferation.

CONCLUSIONS

MiR-196b is overexpressed and confers a poor prognosis via promoting cellular proliferation in GBM patients.

miR-196b directly targets both HOXA9/MEIS1 oncogenes and FAS tumour suppressor in MLL-rearranged leukaemia

HOXA9 and MEIS1 have essential oncogenic roles in mixed lineage leukaemia (MLL)-rearranged leukaemia. Here we show that they are direct targets of miRNA-196b, a microRNA (miRNA) located adjacent to and co-expressed with HOXA9, in MLL-rearranged leukaemic cells. Forced expression of miR-196b significantly delays MLL-fusion-mediated leukemogenesis in primary bone marrow transplantation through suppressing Hoxa9/Meis1 expression. However, ectopic expression of miR-196b results in more aggressive leukaemic phenotypes and causes much faster leukemogenesis in secondary transplantation than MLL fusion alone, likely through the further repression of Fas expression, a proapoptotic gene downregulated in MLL-rearranged leukaemia. Overexpression of FAS significantly inhibits leukemogenesis and reverses miR-196b-mediated phenotypes. Targeting Hoxa9/Meis1 and Fas by miR-196b is probably also important for normal haematopoiesis. Thus, our results uncover a previously unappreciated miRNA-regulation mechanism by which a single miRNA may target both oncogenes and tumour suppressors, simultaneously, or, sequentially, in tumourigenesis and normal development per cell differentiation, indicating that miRNA regulation is much more complex than previously thought.

Transcriptional regulation of miR-196b by ETS2 in gastric cancer cells

E26 transformation-specific sequence (ETS)-2 is a transcriptional modulator located on chromosome 21, alterations in its expression have been implicated with a reduced incidence of solid tumors in Down syndrome patients. MicroRNAs (miRNAs) are thought to participate in diverse biological functions; however, the regulation of miRNAs is not well characterized. Recently, we reported that miR-196b is highly expressed in gastric cancers. Herein, we demonstrate that miR-196b expression was significantly repressed by ETS2 during gastric cancer oncogenesis. We demonstrate that knockdown of endogenous ETS2 expression increases miR-196b expression. A genomic region between −751 and −824 bp upstream of the miR-196b transcriptional start site was found to be critical for the repression activity. This putative regulatory promoter region contains three potential ETS2-binding motifs. Mutations within the ETS2 binding sites blocked the repression activity of ETS2. Furthermore, knockdown of ETS2 or overexpression of miR-196b significantly induced migration and invasion in gastric cancer cells. In addition, alterations in ETS2 and miR-196b expression in gastric cancer cell lines affected the expression of epithelial–mesenchymal transition-related genes. The levels of vimentin, matrix metalloproteinase (MMP)-2 and MMP9 were drastically induced, but levels of E-cadherin were decreased in shETS2- or miR-196b-transfected cells. Our data indicate that ETS2 plays a key role in controlling the expression of miR-196b, and miR-196b may mediate the tumor suppressor effects of ETS2. We demonstrated that miR-196b was transcriptionally regulated by ETS2 and there was an inverse expression profile between miR-196b and ETS2 in clinical samples. This finding could be beneficial for the development of effective cancer diagnostic and alternative therapeutic strategies.

Differential miRNA expression in childhood acute lymphoblastic leukemia and association with clinical and biological features

The present study aimed to analyze the expression profile of the microRNAs previously described as associated with childhood ALL, miR-92a, miR-100, miR-125a-5p, miR-128a, miR-181b, miR-196b and let-7e, and their association with biological/prognostic features in 128 consecutive samples of childhood acute lymphoblastic leukemia (ALL) by quantitative real-time PCR. A significant association was observed between higher expression levels of miR-196b and T-ALL, miR-100 and patients with low white blood cell count at diagnosis and t(12;21) positive ALL. These findings suggest a potential activity of these microRNAs in pediatric ALL biology.

Macro-management of microRNAs in cell cycle progression of tumor cells and its implications in anti-cancer therapy

The cell cycle, which is precisely controlled by a number of regulators, including cyclins and cyclin-dependent kinases (CDKs), is crucial for the life cycle of mammals. Cell cycle dysregulation is implicated in many diseases, including cancer. Recently, compelling evidence has been found that microRNAs play important roles in the regulation of cell cycle progression by modulating the expression of cyclins, CDKs and other cell cycle regulators. Herein, the recent findings on the regulation of the cell cycle by microRNAs are summarized, and the potential implications of miRNAs in anti-cancer therapies are discussed.