Decreased expression of miR-125b and miR-100 in oral cancer cells contributes to malignancy

Significance of microRNA-related variants in susceptibility to recurrence of oropharyngeal cancer patients after definitive radiotherapy

Common single nucleotide polymorphisms (SNPs) in miRNAs may affect miRNA functions and their target expression and thus may affect biological activities and cancer etiology as well as prognosis. Thus, we determined whether the 9 SNPs in microRNAs modify the risk of recurrence of squamous cell carcinoma of the oropharynx (SCCOP) in a cohort of 1008 patients. The log-rank test and multivariate Cox models were used to evaluate the associations. We found that the SNPs in the miRNA146, miRNA196, and Gemin3 were associated with a significantly reduced and increased risk of SCCOP recurrence after multivariate adjustment (aHR, 0.6, 95%CI, 0.4-0.9, aHR, 2.1, 95%CI, 1.6-2.8, and aHR, 0.6, 95%CI, 0.5-0.9, respectively). Furthermore, the similar effect of these 3 SNPs on SCCOP recurrence risk was found in HPV-positive SCCOP patients only. However, no significant associations were found for other SNPs. To evaluate the aggregate effects of these SNPs, we performed a combined risk genotype analysis. We found that, compared with the low-risk reference group with less than 4 risk genotypes, the medium-risk group with 4 or 5 risk genotypes exhibited a 1.7-fold (1.2-2.4) increased risk whereas the high-risk group with more than 5 risk genotypes exhibited a 3.0-fold (1.7-4.2) increased risk (P_trend < 0.001). Such combined effects were particularly pronounced in HPV-positive SCCOP patients. Taken together, this is the first study with a large cohort of SCCOP patients showing that miRNA-related genetic variants may modify risk of SCCOP recurrence individually and jointly. Larger studies are needed to validate these results.

Pre-miRNA variants as predictors of clinical outcome in patients with squamous cell carcinomas of the nonoropharynx

Functional polymorphisms of miRNAs may affect the function and target expression of miRNAs, which can, in turn, affect the biological activity, etiology, and prognosis of cancer. We hypothesized that four common polymorphisms in pre-miRNAs (hsa-mir-146a rs2910164 G > C, hsa-mir-196a2 rs11614913 C > T, hsa-mir-149 rs2292832 G > T, and hsa-mir-499 rs3746444 A > G) are associated with survival in SCCNOP. We used univariate and multivariable Cox models to evaluate the associations between the four polymorphisms and survival. We found that hsa-mir-149 rs2292832 and hsa-mir-499 rs3746444 had statistically significant associations with survival, but hsa-mir-146a rs2910164 and hsa-mir-196a2 rs11614913 did not. Patients having the hsa-mir-149 CC and hsa-mir-499 TT wild-type genotypes had significantly better overall, disease-specific, and disease-free survival compared with those who had the corresponding variant CT/TT and CT/CC genotypes, respectively. Furthermore, these genotypes were significantly associated with reduced risk of overall death, death owing to disease, and recurrence after adjustment for important prognostic confounders, indicating that these pre-miRNA polymorphisms may be prognostic biomarkers for SCCNOP. Moreover, the stratified analyses based on smoking status and treatment indicated that the effects of hsa-mir-149 and hsa-mir-499 polymorphisms on survival were more pronounced in ever smokers and patients treated with chemoradiation. Our findings support that the hsa-mir-149 rs2292832 and hsa-mir-499 rs3746444 polymorphisms play a significant role in the prognosis of SCCNOP, especially in smokers and patients treated with chemoradiation. Prospective studies with larger sample sizes are needed to confirm these findings.

"Omics" in oral cancer: New approaches for biomarker discovery

OBJECTIVES

In this review paper, we explored the application of "omics" approaches in the study of oral cancer (OC). It will provide a better understanding of how "omics" approaches may lead to novel biomarker molecules or molecular signatures with potential value in clinical practice. A future direction of "omics"-driven research in OC is also discussed.

METHODS

Studies on "omics"-based approaches [genomics/proteomics/transcriptomics/metabolomics] were investigated for differentiating oral squamous cell carcinoma,oral sub-mucous fibrosis, oral leukoplakia, oral lichen planus, oral erythroplakia from normal cases. Electronic databases viz., PubMed, Springer, and Google Scholar were searched.

RESULTS

One eighty-one studies were included in this review. The review shows that the fields of genomics, transcriptomics, proteomics, and metabolomics-based marker identification have implemented advanced tools to screen early changes in DNA, RNA, protein, and metabolite expression in OC population.

CONCLUSIONS

It may be concluded that despite advances in OC therapy, symptomatic presentation occurs at an advanced stage, where various curative treatment options become very limited. A molecular level study is essential for detecting an OC biomarker at an early stage. Modern "Omics" strategies can potentially make a major contribution to meet this need.

Systematic Analysis of Transcriptomic Profile of Renal Cell Carcinoma under Long-Term Hypoxia Using Next-Generation Sequencing and Bioinformatics

Patients with clear cell renal cell carcinoma (ccRCC) are often diagnosed with both von Hippel-Lindau (VHL) mutations and the constitutive activation of hypoxia-inducible factor-dependent signaling. In this study, we investigated the effects of long-term hypoxia in 786-O, a VHL-defective renal cell carcinoma cell line, to identify potential genes and microRNAs associated with tumor malignancy. The transcriptomic profiles of 786-O under normoxia, short-term hypoxia and long-term hypoxia were analyzed using next-generation sequencing. The results showed that long-term hypoxia promoted the ability of colony formation and transwell migration compared to normoxia. In addition, the differentially expressed genes induced by long-term hypoxia were involved in various biological processes including cell proliferation, the tumor necrosis factor signaling pathway, basal cell carcinoma and cancer pathways. The upregulated (L1CAM and FBN1) and downregulated (AUTS2, MAPT, AGT and USH1C) genes in 786-O under long-term hypoxia were also observed in clinical ccRCC samples along with malignant grade. The expressions of these genes were significantly correlated with survival outcomes in patients with renal cancer. We also found that long-term hypoxia in 786-O resulted in decreased expressions of hsa-mir-100 and hsa-mir-378 and this effect was also observed in samples of metastatic ccRCC compared to samples of non-metastatic ccRCC. These findings may provide a new direction for the study of potential molecular mechanisms associated with the progression of ccRCC.

A Looking-Glass of Non-coding RNAs in oral cancer

Oral cancer is a multifactorial pathology and is characterized by the lack of efficient treatment and accurate diagnostic tools. This is mainly due the late diagnosis; therefore, reliable biomarkers for the timely detection of the disease and patient stratification are required. Non-coding RNAs (ncRNAs) are key elements in the physiological and pathological processes of various cancers, which is also reflected in oral cancer development and progression. A better understanding of their role could give a more thorough perspective on the future treatment options for this cancer type. This review offers a glimpse into the ncRNA involvement in oral cancer, which can help the medical community tap into the world of ncRNAs and lay the ground for more powerful diagnostic, prognostic and treatment tools for oral cancer that will ultimately help build a brighter future for these patients.

Stem Cell-Derived Exosomes, Autophagy, Extracellular Matrix Turnover, and miRNAs in Cardiac Regeneration during Stem Cell Therapy

Stem cell therapy (SCT) raises the hope for cardiac regeneration in ischemic hearts. However, underlying molecular mechanisms for repair of dead myocardium by SCT in the ischemic heart is poorly understood. Growing evidences suggest that cardiac matrix stiffness and differential expressions of miRNAs play a crucial role in stem cell survival and differentiation. However, their roles on transplanted stem cells, for myocardial repair of the ischemic heart, remain unclear. Transplanted stem cells may act in an autocrine and/or paracrine manner to regenerate the dead myocardium. Paracrine mediators such as stem cell-derived exosomes are emerging as a novel therapeutic strategy to overcome some of the limitations of SCT. These exosomes carry microRNAs (miRNAs) that may regulate stem cell differentiation into a specific lineage. MicroRNAs may also contribute to stiffness of surrounding matrix by regulating extracellular matrix (ECM) turnover. The survival of transplanted stem cell depends on its autophagic process that maintains cellular homeostasis. Therefore, exosomes, miRNAs, extracellular matrix turnover, and autophagy may have an integral role in improving the efficacy of SCT. This review elaborates the specific roles of these regulatory components on cardiac regeneration in the ischemic heart during SCT.

miRNAs: Important Targets for Oral Cancer Pain Research

Pain is a symptom shared by an incredible number of diseases. It is also one of the primary conditions that prompt individuals to seek medical treatment. Head and neck squamous cell carcinoma (HNSCC) corresponds to a heterogeneous disease that may arise from many distinct structures of a large, highly complex, and intricate region. HNSCC affects a great number of patients worldwide and is directly associated with chronic pain, which is especially prominent during the advanced stages of oral squamous cell carcinoma (OSCC), an anatomical and clinical subtype that corresponds to the great majority oral cancers. Although the cellular and molecular bases of oral cancer pain have not been fully established yet, the results of recent studies suggest that different epigenetic mechanisms may contribute to this process. For instance, there is strong scientific evidence that microRNAs (miRNAs), small RNA molecules that do not encode proteins, might act by regulating the mechanisms underlying cancer-related pain. Among the miRNAs that could possibly interfere in pain-signaling pathways, miR-125b, miR-181, and miR-339 emerge as some of the most promising candidates. In fact, such molecules apparently contribute to inflammatory pain. Moreover, these molecules possibly influence the activity of endogenous pain control systems (e.g., opioidergic and serotonergic systems), which could ultimately result in peripheral and central sensitization, central nervous system (CNS) phenomena innately associated with chronic pain. This review paper focuses on the current scientific knowledge regarding the involvement of miRNAs in cancer pain, with special attention dedicated to OSCC-related pain.

Differential expression and androgen regulation of microRNAs and metalloprotease 13 in breast cancer cells

MicroRNA molecules (miRNAs) play important roles in regulating cell behavior. The expression of certain miRNAs has been shown to be regulated by the androgen receptor (AR), which seems to have a critical role in the tumorigenic process of breast cancer. The differential expression of 84 miRNAs was first examined in three breast cancer cell lines: the luminal MCF-7 and T47D cells and the molecular apocrine MDA-MB-453 cells. Analysis of basal expression of miRNAs revealed that each cell line had distinct miRNA expression where let-7a and -7b were markers of MDA-MB-453 cells, whereas miR-205 was a marker for the luminal cell lines. Treating the cells with the AR agonist, CI-4AS-1, resulted in unique alterations in the expression of specific miRNA among the three cell lines. Particularly, the expression of miR-100 and miR-125 was reduced in MDA-MB-453 cells by five and three folds, respectively. This effect was simultaneous with AR-induced increase in the expression and extracellular release of metalloprotease-13 (MMP13). Transfection of cells with either miR-100 or miR-125b negated the induction of MMP13 release. Additionally, AR activation induced a morphological alteration of MDA-MB-453 cells, which was blocked by miR-125b only. Collectively, these data indicate that AR may control the biological behavior of breast cancer cells and protein expression via miRNAs.

Animal Models to Study MicroRNA Function

The discovery of the microRNAs, lin-4 and let-7 as critical mediators of normal development in Caenorhabditis elegans and their conservation throughout evolution has spearheaded research toward identifying novel roles of microRNAs in other cellular processes. To accurately elucidate these fundamental functions, especially in the context of an intact organism, various microRNA transgenic models have been generated and evaluated. Transgenic C. elegans (worms), Drosophila melanogaster (flies), Danio rerio (zebrafish), and Mus musculus (mouse) have contributed immensely toward uncovering the roles of multiple microRNAs in cellular processes such as proliferation, differentiation, and apoptosis, pathways that are severely altered in human diseases such as cancer. The simple model organisms, C. elegans, D. melanogaster, and D. rerio, do not develop cancers but have proved to be convenient systesm in microRNA research, especially in characterizing the microRNA biogenesis machinery which is often dysregulated during human tumorigenesis. The microRNA-dependent events delineated via these simple in vivo systems have been further verified in vitro, and in more complex models of cancers, such as M. musculus. The focus of this review is to provide an overview of the important contributions made in the microRNA field using model organisms. The simple model systems provided the basis for the importance of microRNAs in normal cellular physiology, while the more complex animal systems provided evidence for the role of microRNAs dysregulation in cancers. Highlights include an overview of the various strategies used to generate transgenic organisms and a review of the use of transgenic mice for evaluating preclinical efficacy of microRNA-based cancer therapeutics.

Association between polymorphisms in pre-miRNA genes and risk of oral squamous cell cancer in a Chinese population

Background

MicroRNAs play important roles in the development of human cancers. This case-control study is to evaluate the roles of the polymorphisms in pre-miRNAs on risk of oral cancer in a Chinese population.

Methods

The genotypes of three polymorphisms were determined in 340 patients with oral squamous cell cancer and 340 healthy controls who were frequency matched for age and sex. Odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated to assess the association. All analyses were performed using the SPSS software. 3.154() 0.001.

Results

For miR-499 rs3746444, individuals carrying homozygous CC genotype had increased risks of oral cancer compared with the homozygous wild TT genotype (adjusted OR was 3.154, 95%CI was 1.555–6.397, P value was 0.001). The C allele of miR-499 rs3746444 was associated with a higher risk of oral cancer with significant odds ratio of 1.453. In the stratified analyses by sex, the associations between miR-499 rs3746444 and miR-146a rs2910164 polymorphisms with the susceptibility of oral squamous cell cancer were significant in males. However, with 1/4 as many subjects there were no significant associations between the three polymorphisms and oral cancer risks in females. The joint effects of miRNA polymorphisms and smoking on the risk of OSCC were analyzed and the results suggested that the association between microRNA genetic variants and OSCC risk was modified by smoking.

Conclusions

These findings suggest that miR-499 rs3746444 and miR-146a rs2910164 polymorphisms may contribute to genetic susceptibility to oral squamous cell cancer.

MicroRNA-125b targeted STAT3 to inhibit laryngeal squamous cell carcinoma cell growth and motility

A majority of studies have indicated that microRNA-125b (miR-125b) is aberrantly expressed in various types of cancer. However, there are no studies on the expression and function of miR-125b in human laryngeal squamous cell carcinoma (LSCC). In the present study, miR-125b expression in LSCC sample tissues, corresponding adjacent non-neoplastic tissues, LSCC cell lines and a normal human keratinocyte cell line was measured using the reverse transcription-quantitative polymerase chain reaction. Following transfection with miR-125b mimics, the Cell Counting Kit-8, cell migration, cell invasion, western blotting and dual-luciferase reporter assays were performed on LSCC cell lines. According to the results, miR-125b was observed to be significantly downregulated in LSCC, and its expression was significantly associated with clinical stage and alcohol history. miR-125b was also observed to decrease cell growth, migration and invasion in LSCC cells by directly targeting signal transducer and activator of transcription 3. The results of the present study suggested that miR-125b may be a potential treatment target of LSCC in the future.

Comparison of microRNA profiles between benign and malignant salivary gland tumors in tissue, blood and saliva samples: a prospective, case-control study

INTRODUCTION

Salivary gland tumors (SGTs) are rare head and neck malignancies consisting of a spectrum of tumors with different biological behaviors.

OBJECTIVE

In this study we aimed to find out differential expression of microRNA profiles between benign and malignant SGTs.

METHODS

We investigated the possible role of 95 microRNAs in the 20 patients with salivary gland tumors with comparison of 17 patients without malignancy or salivary gland diseases. Sixteen of the tumors were benign (seven pleomorphic adenomas, nine Warthin tumors), four of them were malignant (two squamous cell carcinomas, one high grade mucoepidermoid carcinoma, one adenocarcinoma). Serum and saliva samples were collected from both patients and control group. Tissue samples of tumor masses were also collected from patient group.

RESULTS

Among studied microRNAs miR-21, miR-23a, miR-27a, miR-223, miR-125b, miR-126, miR-146a, miR-30e were down regulated in the benign group compared to control group in the serum samples (p-values are 0.04, 0.00005, 0.00005, 0.0022, 0.031, 0.00008, 0.044, and 0.0007, respectively). When tissue samples were studied miR-21, miR-31, miR-199a-5p, miR-146b, miR-345 were up-regulated in the malignant group compared to benign group (p values are 0.006, 0.02, 0.013, 0.013, 0.041, respectively). miR-30e showed statistically significant up-regulation in malignant tumor group's plasma samples compared to benign group (p=0.034). There was no statistically significant difference in saliva samples between groups.

CONCLUSION

Our results showed that different microRNAs may play role in salivary tumor pathogenesis according to biological behavior. Although there was no difference in saliva samples between groups, according to tissue and serum samples miR-21 and 30e may have an important role; since they were down-regulated in benign tumors whereas up-regulated in malignant ones.

Impact of microRNA dynamics on cancer hallmarks: An oral cancer scenario

MicroRNAs are endogenous small noncoding RNAs that negatively regulate gene expression at posttranscriptional level. The discovery of microRNAs has identified a new layer of gene regulation mechanisms, which play a pivotal role in development as well as in various cellular processes, such as proliferation, differentiation, cell growth, and cell death. Deregulated microRNA expression favors acquisition of cancer hallmark traits as well as transforms the tumor microenvironment, leading to tumor development and progression. Many recent studies have revealed altered expression of microRNAs in oral carcinoma with several microRNAs shown to have key biological role in tumorigenesis functioning either as tumor suppressors or as tumor promoters. MicroRNA expression levels correlate with clinicopathological variables and have a diagnostic and prognostic value in oral carcinoma. For these reasons, microRNA has been a hot topic in oral cancer research for the last few years. In this review, we attempt to summarize the present understanding of microRNA deregulation in oral carcinoma, their role in acquiring cancer hallmarks, and their potential diagnostic and prognostic value for oral cancer management.

Lower Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Promotes the Proliferation and Migration of Endometrial Carcinoma

BACKGROUND The incidence and death rates of endometrial cancer are alarmingly increasing. The diagnosis and treatment of endometrial cancer is crucial to decreasing mortality. Cystic fibrosis transmembrane conductance regulator (CFTR) belongs to the adenosine triphosphate (ATP)-binding cassette transporter family and plays an essential role in anion regulation and tissue homeostasis of various epithelia. This study explored the expression of CFTR in endometrial carcinoma and the role of CFTR in proliferation and migration of endometrial carcinoma cells. MATERIAL AND METHODS Immunohistochemistry and real-time (RT)-PCR were used to test the expression of CFTR in normal endometrium and endometrial carcinoma. CFTR inhibitor was used to restrain the expression of CFTR on the endometrial carcinoma, the effects on the proliferation and migration of endometrial carcinoma cells were also studied. RT-PCR was performed to test the expression of mir-125b after restraining CFTR. Proliferation and migration capability of endometrial carcinoma cells were detected after transfection of endometrial carcinoma cells with mir-125b mimic. RESULTS Compared with cells from normal endometrium, the expression of CFTR was significantly upregulated in endometrial carcinoma cells. After adding CFTR(inh)172, the capability for proliferation and transfer of endometrial carcinoma cells was strengthened, the expression of mir-125b was reduced, and after transfection with mir-125b mimics entering the endometrial carcinoma cells, the ability of the proliferation and transfer of endometrial carcinoma cells was also reduced. CONCLUSIONS The high expression of CFTR in the endometrial carcinoma cells played a pivotal role in restraining the proliferation and transfer of endometrial carcinoma cells.

Roles of FGFR in oral carcinogenesis

Fibroblast growth factor receptors (FGFRs) play essential roles in organ development during the embryonic period, and regulate tissue repair in adults. Accumulating evidence suggests that alterations in FGFR signalling are involved in diverse types of cancer. In this review, we focus on aberrant regulation of FGFRs in pathogenesis of oral squamous cell carcinoma (OSCC), including altered expression and subcellular location, aberrant isoform splicing and mutations. We also provide an overview of oncogenic roles of each FGFR and its downstream signalling pathways in regulating OSCC cell proliferation and metastasis. Finally, we discuss potential application of FGFRs as anti-cancer targets in the preclinical environment and in clinical practice.

Prognostic significance of microRNA-100 in solid tumors: an updated meta-analysis

Objective

The aim of this study was to identify prognostic significance of microRNA-100 (miR-100) in solid tumor.

Methods

Literature search was conducted in databases such as PubMed, Embase, and Web of Science, using the following words “(microRNA-100 OR miR-100 OR mir100) AND (tumor OR neoplasm OR cancer OR carcinoma OR malignancy).” The search was updated up until July 10, 2016. Newcastle–Ottawa scale was used to evaluate the quality of studies. Pooled hazard ratio (HR) with 95% confidence interval (CI) for patients’ survival was calculated by using a fixed-effects or a random-effects model on the basis of heterogeneity. Subgroup analysis, sensitive analysis, and meta-regression were used to investigate the sources of heterogeneity. Publication bias was evaluated by using Begg’s and Egger’s tests.

Results

A total of 16 articles with 1,501 patients were included in the present meta-analysis. It was demonstrated that a lower expression of miR-100 plays a negative role in the overall survival (OS) of patients with solid tumor (HR =1.92; 95% CI =1.25–2.94). In addition, the association between miR-100 and prognosis was also revealed in the following subgroups: non-small-cell lung cancer (NSCLC; HR =2.46; 95% CI =1.98–3.06), epithelial ovarian cancer (EOC; HR =2.29, 95% CI =1.72–3.04), and bladder cancer (BC; HR =4.14, 95% CI =1.85–9.27).

Conclusion

This meta-analysis indicates that lower expression of miR-100 is related to poorer OS in patients with solid tumor, especially in those with NSCLC, EOC, and BC. MiR-100 is a promising prognosis predictor and may be a potential target for therapy in the future.

Elevated microRNA-125b levels predict a worse prognosis in HER2-positive breast cancer patients

Breast cancer, the second most common cancer worldwide, is the leading cause of cancer-associated mortality in women, accounting for ~15% of all cancer-associated mortalities in women. The development, local invasion and metastasis of breast cancer are associated with the dysregulation and mutation of numerous genes and epigenetic mechanisms, including coding RNA and non-coding RNA, such as microRNAs (miRs/miRNAs). Previous studies have shown a dual-faced role of miR-125b in breast cancer. In the present study, a total of 221 paraffin-embedded breast cancer and 49 paraffin-embedded non-cancerous breast tissue samples were collected. In situ hybridization was used to analyze the expression of miR-125b in the breast cancer tissues. Spearman's rank correlation analysis was used to analyze the expression correlation between miR-125b and human epidermal growth factor 2 (HER2). The overall survival estimates over time were calculated using the Kaplan-Meier method with log-rank test. It was found that miR-125b expression was significantly increased in the breast cancer tissues compared with that in the non-cancerous tissues, and high miR-125b expression indicated a poor prognosis in the breast cancer patients. In addition, miR-125b expression was positively correlated with HER2, but not with progesterone receptor and estrogen receptor. Notably, high miR-125b expression was significantly correlated with tumor size and Tumor-Node-Metastasis stage in the HER2-positive breast cancer patients, along with a poor prognosis. The present study provides clinical data to confirm the oncogenic potential of miR-125b, particularly in HER2-positive human breast cancer. Thus, identification of miR-125b may be a potential molecular biomarker for the prediction of clinical outcomes in breast cancer patients, particularly HER2-positive cases that will receive paclitaxel-based neoadjuvant chemotherapy.

Lymph node or perineural invasion is associated with low miR-15a, miR-34c and miR-199b levels in head and neck squamous cell carcinoma

Background

MicroRNAs (miRNAs or miRs) are post-transcriptional regulators of eukaryotic cells and knowledge of differences in miR levels may provide new approaches to diagnosis and therapy.

Methods

The present study measured the levels of nine miRs in head and neck squamous cell carcinomas (HNSCC) and determined whether clinical pathological features are associated with differences in miR levels. SET (I2PP2A) and PTEN protein levels were also measured, since their levels can be regulated by miR-199b and miR-21, respectively. Nine miRs (miR-15a, miR-21, miR-29b, miR-34c, miR-100, miR-125b, miR-137, miR-133b and miR-199b) were measured by real time qRT-PCR in HNSCC samples from 32 patients and eight resection margins. SET (I2PP2A) and PTEN protein levels were estimated by immunohistochemistry in paired HNSCC tissues and their matched resection margins.

Results

In HNSCC, the presence of lymph node invasion was associated with low miR-15a, miR-34c and miR-199b levels, whereas the presence of perineural invasion was associated with low miR-199b levels. In addition, miR-21 levels were high whereas miR-100 and miR-125b levels were low in HNSCC compared to the resection margins. When HNSCC line HN12, with or without knockdown of SET, were transfected with miR-34c inhibitor or miR-34c mimic, the miR-34c inhibitor increased cell invasion capacity while miR-34c mimic decreased the cell invasion.

Conclusions

We showed that the levels of specific miRs in tumor tissue can provide insight into the maintenance and progression of HNSCC.

General significance

MiRNAs are up- or down-regulated during cancer development and progression; they can be prognosis markers and therapeutic targets in HNSCC.

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Association between miR-15a, miR-34c and miR-199b levels and lymph node metastasis in HNSCC.

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miR-199b is reduced while SET protein is accumulated in HNSCC.

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Levels of miR-34c control invasion in HNSCC.

miR-100 antagonism triggers apoptosis by inhibiting ubiquitination-mediated p53 degradation

During tumourigenesis, p53 functions as 'the guardian of the genome' because p53-dependent apoptosis strongly regulates the fate of cancer cells. Therefore, p53 regulation must be sensitive and accurate. p53 activity is regulated through its ubiquitination and deubiquitination. However, the role of microRNA in ubiquitin-mediated p53 degradation has not been previously studied. Our previous studies indicated that miR-100 is required for apoptosis. In the current study, the mechanism of p53 protein ubiquitination mediated by miR-100 was characterized. An analysis of primary tumour samples from gastric cancer patients showed a significant correlation between miR-100 upregulation and primary human gastric tumourigenesis and progression. The in vivo and in vitro data indicated that miR-100 antagonism specifically induced the apoptosis of poorly differentiated gastric cancer cells but not non-cancerous gastric cells, indicating that miR-100 has a crucial role in regulating the progression of gastric tumours. In the regulation of p53-dependent apoptosis, miR-100 antagonism inhibited ubiquitin-mediated p53 protein degradation by activating RNF144B, an E3 ubiquitination ligase. Consequently, the miR-100-RNF144B-pirh2-p53-dependent pathway was initiated. Our findings highlight a novel mechanism of ubiquitin-mediated p53 protein degradation in apoptosis.

A restricted signature of serum miRNAs distinguishes glioblastoma from lower grade gliomas

Background

Malignant gliomas are the most common primary brain tumors in adults and challenging cancers for diagnosis and treatment. They remain a disease for which non-invasive, diagnostic and/or prognostic novel biomarkers are highly desirable. Altered microRNA (miRNA) profiles have been observed in tumor tissues and biological fluids. To date only a small set of circulating/serum miRNA is found to be differentially expressed in brain tumors compared to normal controls.

Here a restricted signature of circulating/serum miRNA including miR-15b*,-23a, −99a, −125b, −133a, −150*, −197, −340, −497, −548b-5p and let-7c were investigated as potential non-invasive biomarkers in the diagnosis of glioma patients.

Methods

Serum and tissues miRNAs expression in patients with brain cancers (n = 30) and healthy controls (n = 15) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Relative expression was calculated using the comparative Ct method. Statistical significance (p ≤ 0,05) was determined using the Mann–Whitney rank sum and Fisher’s exact test. Diagnostic accuracy of miRNAs in distinguishing glioblastoma multiforme (GBM) from lower grade cancer was assessed by the Receiver Operating Characteristic (ROC) curve analysis.

To validate the role of the identified miRNAs in cancer a comprehensive literature search was conducted using PubMed, Web of Science (Core Collection) and Scopus databases.

Results

We observed a decrease of miR-497 and miR-125b serum levels depending on tumor stages with reduced level in GBM than lower grade tumors. The ROC curve analysis distinguishing GBM from lower grade cases yielded an area under the curve (AUC) of 0.87 (95 % confidence interval (CI) = 0.712–1) and of 0.75 (95 % CI = 0.533–0.967) for miR-497 and -125b, respectively. GBM patients are more likely to show a miR-497 and -125b down-regulation than the lower grade group (p = 0.002 and p = 0.024, respectively). These results were subsequently compared with evidence from 19 studies included in the final systematic review.

Conclusions

Although multiple biomarkers are currently leveraged in the clinic to detect specific cancer types, no such standard blood biomolecules are used as yet in gliomas. Our data suggest that serum miR-497 and -125b could be a novel diagnostic markers with good perspectives for future clinical applications in patients with glioma.

Comparison of the miRNA profiles in HPV-positive and HPV-negative tonsillar tumors and a model system of human keratinocyte clones

BACKGROUND

Better insights into the molecular changes involved in virus-associated and -independent head and neck cancer may advance our knowledge of HNC carcinogenesis and identify critical disease biomarkers. Here we aimed to characterize the expression profiles in a matched set of well-characterized HPV-dependent and HPV-independent tonsillar tumors and equivalent immortalized keratinocyte clones to define potential and clinically relevant biomarkers of HNC of different etiology.

METHODS

Fresh frozen tonsillar cancer tissues were analyzed together with non-malignant tonsillar tissues and compared with cervical tumors and normal cervical tissues. Furthermore, relative miRNAs abundance levels of primary and immortalized human keratinocyte clones were evaluated. The global quantitation of miRNA gene abundance was performed using a TaqMan Low Density Array system. The confirmation of differentially expressed miRNAs was performed on a set of formalin-fixed paraffin-embedded tumor samples enriched for the tumor cell fraction by macrodissection.

RESULTS

We defined 46 upregulated and 31 downregulated miRNAs characteristic for the HPV-positive tonsillar tumors and 42 upregulated miRNAs and 42 downregulated miRNAs characteristic for HPV-independent tumors. In comparison with the expression profiles in cervical tumors, we defined miR-141-3p, miR-15b-5p, miR-200a-3p, miR-302c-3p, and miR-9-5p as specific for HPV induced malignancies. MiR-335-5p, miR-579-3p, and miR-126-5p were shared by the expression profiles of HPV-positive tonsillar tumors and of the HPV immortalized keratinocyte clones, whereas miR-328-3p, miR-34c-3p, and miR-885-5p were shared by the miRNA profiles of HPV-negative tonsillar tumors and the HPV-negative keratinocytes.

CONCLUSIONS

We identified the miRNAs characteristic for HPV-induced tumors and tonsillar tumors of different etiology, and the results were compared with those of the model system. Our report presents the basis for further investigations leading to the identification of clinically relevant diagnostic and/or therapeutic biomarkers for tumors of viral and non-viral etiology.

Predicting associations between microRNAs and target genes in breast cancer by bioinformatics analyses

Breast cancer is the leading type of cancer among females. However, the association between microRNAs (miRNAs) and target genes in breast tumorigenesis is poorly studied. The original data set GSE26659 was downloaded from the Gene Expression Omnibus, and then the differentially expressed miRNAs among 77 breast cancer patients and 17 controls were identified using the Limma package in R software. Furthermore, breast cancer-related differentially expressed miRNAs were selected from a human miRNA disease database and their target genes were selected from five miRNA databases. Then, functional analysis was performed for the target genes followed by construction of a miRNA-target gene network. A total of 34 differentially expressed miRNAs were identified, including 13 breast cancer-related miRNAs. Moreover, the target genes of the 13 miRNAs were significantly enriched in regulation of transcription (P=7.43E-09) and pathways related to cancer (P=3.33E-11). Finally, eight upregulated miRNAs (including hsa-miR-425) and five downregulated miRNAs (including hsa-miR-143, hsa-miR-145 and hsa-miR-125b) were identified in the miRNA-target gene network. In conclusion, using bioinformatics approaches, we demonstrate that the changes in regulation of transcription and cancer pathways may play significant roles in the process of breast cancerogenesis. Differentially expressed miRNAs and their target genes may be new targets for breast cancer therapy.

miRNAs Signature in Head and Neck Squamous Cell Carcinoma Metastasis: A Literature Review

STATEMENT OF THE PROBLEM

Head and neck cancers include epithelial tumors arising in the oral cavity, pharynx, larynx, paranasal sinuses, and nasal cavity. Metastasis is a hallmark of cancer. MicroRNAs (miRNAs) are endogenous small non-coding RNAs involved in cell proliferation, development, differentiation and metastasis. It is believed that miRNA alterations correlate with initiation and progression of cancer cell proliferation or inhibition of tumorigenesis. Moreover, miRNAs have different roles in development, progression, and metastasis of head and neck squamous cell carcinoma (HNSCC). Altered expression of miRNAs could be novel molecular biomarkers for the definite diagnosis of cancer, metastatic site, cancer stage, and its progression.

PURPOSE

The purpose of this review was to provide a comprehensive literature review of the role of miRNAs in head and neck cancer metastasis.

SEARCH STRATEGY

A relevant English literature search in PubMed, ScienceDirect, and Google Scholar was performed. The keywords 'miRNA', 'head and neck', and 'cancer' were searched in title and abstract of publications; limited from 1990 to 2015. The inclusion criterion was the role of miRNAs in cancer metastasis. The exclusion criterion was the other functions of miRNAs in cancers. Out of 15221 articles, the full texts of 442 articles were retrieved and only 133 articles met the inclusion criteria.

CONCLUSION

Despite the advances in cancer treatment, the mortality rate of HNSCC is still high. The potential application of miRNAs for cancer therapy has been demonstrated in many studies; miRNAs function as either tumor suppressor or oncogene. The recognition of metastamir and their targets may lead to better understanding of HNSCC oncogenesis, and consequently, development of new therapeutic strategies which is a necessity in cancer treatment. Development of therapeutic agents based on miRNAs is a promising target.

The role and expression of miR-100 and miR-203 profile as prognostic markers in epithelial ovarian cancer

PURPOSE

The present study was aimed to evaluate the clinical significance of miR-100 and miR-203 in epithelial ovarian cancer (EOC) patients.

METHODS

The expression levels of miR-100/203 in EOC tissue and adjacent non-cancerous samples were determined by real-time RT-PCR. Associations between miRNAs expressions and various clinicopathological characteristics were analyzed. Survival rate was determined with Kaplan-Meier and statistically analyzed with the log-rank method between groups. Survival data were evaluated through multivariate. Cox regression analysis.

FINDINGS

Our findings showed that miR-100 was significantly down-regulated in EOC tissue specimens than in adjacent non-cancerous tissues. The expression level of miR-203 was significantly higher in EOC tissues compared to adjacent non-cancerous tissues. Decreased expression of miR-100 was strongly associated with high FIGO stage (P=0.012). The high expression of miR-203 was significantly correlated with advanced FIGO stage (p=0.006), advanced histological grade (p=0.03). Kaplan-Meier analysis and log-rank test have suggested that EOC patients with down-regulated miR-100 expression and up-regulated miR-203 expression have shorter overall survival when compared with patients with other expression groups (log-rank test P<0.001). Multivariate Cox proportional hazards model indicated that the status of miR-100 and miR-203 expression levels were independent predictor of overall survival in patients with EOC.

CONCLUSION

Decreased expression and increased expression of miR-100 and miR-203 may be correlated with progression and poor prognosis of EOC.

MiR-744 functions as a proto-oncogene in nasopharyngeal carcinoma progression and metastasis via transcriptional control of ARHGAP5

Nasopharyngeal carcinoma (NPC) is a highly invasive and metastasis-prone epithelial cancer. The paucity of effective treatment strategies for recurrent and metastatic NPC is the major cause for stagnating survival rate of NPC. Therefore, it's urgent to understand the molecular mechanisms underlying NPC progression and identify novel avenues for targeted therapy. It has emerged recently that microRNAs are potential pro-tumorigenic or tumor-suppressive factors that participate in oncogenesis. In this study, we found that miR-744 expression was upregulated in NPC specimens compared to nasopharyngeal epithelium (NPE) tissue, and miR- 744 upregulation was significantly associated with TNM stage, tumorigenesis and metastasis. Functional studies revealed that miR-744 acts as a novel tumor promotor in NPC. Moreover, we determined that miR-744 targets ARHGAP5 (Rho GTPase activating protein 5), a protumorigenic gene, by directly interacting with its promoter and thereby regulating its expression at transcriptional level. Reintroduction of ARHGAP5 resembled the effects of miR-744 and silencing of ARHGAP5 clearly abrogated miR-744-induced enhancement of cell migration and invasion. High level of ARHGAP5 was positively correlated with that of miR-744 and with advanced stages of NPC, as well as with lymph node metastasis. Taken together, these data reveal for the first time that miR-744 exerts its proto-oncogenic function by directly targeting ARHGAP5 promoter. This newly identified miR-744/ARHGAP5 pathway provides further insight into the progression and metastasis of NPC and indicates potential novel therapeutic targets for NPC.

miR-125b inhibits keratinocyte proliferation and promotes keratinocyte apoptosis in oral lichen planus by targeting MMP-2 expression through PI3K/Akt/mTOR pathway

Oral lichen planus (OLP) is a chronic inflammatory mucosal disease that involves the degeneration of keratinocytes. However, the etiology and mechanisms of OLP pathogenesis have not been fully elucidated. In this study, we used keratinocytes HaCaT stimulated with lipopolysaccharide (LPS) to mimic a local OLP immune environment, and investigated the regulatory role of miR-125b in keratinocyte proliferation and apoptosis under OLP conditions. Immunohistochemical analysis and quantitative real-time PCR (qRT-PCR) assay showed that MMP-2 expression was up-regulated and miR-125b expression was down-regulated in both OLP mucosa tissues and LPS-incubated HaCaT cells. Western blot analysis indicated that miR-125b overexpression suppressed LPS-induced MMP-2 expression in HaCaT cells. Molecularly, our results confirmed that MMP-2 is a target gene of miR-125b in HaCaT cells. The effect of miR-125b on cell proliferation was revealed by CCK-8 assay, BrdU assay and cell cycle analysis, which illustrated that miR-125b overexpression impeded LPS-induced HaCaT cell proliferation. Flow cytometry analysis further demonstrated that miR-125b overexpression promoted HaCaT cell apoptosis. Moreover, these effects were involved in PI3K/Akt/mTOR activation, as miR-125b overexpression inhibited LPS-enhanced expression of p-Akt and p-mTOR proteins. Taken together, these data confirm that miR-125b might inhibit keratinocyte proliferation and promote keratinocyte apoptosis in OLP pathogenesis by targeting MMP-2 through PI3K/Akt/mTOR pathway.

MiR-125b Regulates Primordial Follicle Assembly by Targeting Activin Receptor Type 2a in Neonatal Mouse Ovary

The establishment of the primordial follicle pool is crucial for fertility in mammalian females, and the interruption of overall micro-RNA production byDicer1conditional knockout in the female reproductive system results in infertility. However, there are few reports about the functions of individual micro-RNA in regulating primordial follicle assembly. The present study aimed to investigate the function of miR-125b, which is conserved and preferentially expressed in mammalian ovary during primordial follicle assembly. Detection of miR-125b in the developing mouse ovaries by real-time PCR and in situ hybridization showed that it was highly expressed perinatally and specifically located in the ovarian somatic cells. MiR-125b overexpression blocked the process of primordial follicle assembly in cultured newborn mouse ovaries, while its knockdown promoted this process. Further studies showed that miR-125b regulated the activin/Smad2 signaling in neonatal mouse ovary by directly targeting the 3'-untranslated region of activin receptor type 2a (Acvr2a). Overexpression of miR-125b in neonatal mouse ovary suppressed theAcvr2aprotein level, attenuating activin/Smad2 signaling, while knockdown of miR-125b showed the opposite effects. In addition, recombinant human activin A (rh-ActA) down-regulated miR-125b in the neonatal mouse ovary. Overexpression of miR-125b attenuated the promoting effects of rh-ActA on primordial follicle assembly. Taken together, these data suggest that miR-125b blocks the process of primordial follicle assembly, and miR-125b may play this role by regulating the expression ofAcvr2ain the activin/Smad2 signaling pathway.

[The role of microRNAs in head and neck squamous cell carcinoma : Biomarkers for prognosis, therapy selection, and novel therapeutics]

Despite recent advances in radiochemotherapy, treatment of locally advanced head and neck squamous cell carcinoma is still challenging, and survival rates have improved only slightly. This is due to the high frequency of metastases and local and/or regional tumor recurrences that have acquired radio- or chemoresistance. MiRNAs regulate diverse processes in tumorigenesis, metastasis, and therapy resistance in head and neck squamous cell carcinoma. Hence, miRNAs are highly valued in biomarker studies. Establishment of the miRNA profiles of oropharyngeal tumors enables personalized treatment selection, since expression of distinct miRNAs can predict the response to two different radiochemotherapy regimens. Development of novel miRNA therapeutics has a high clinical potential for further improving treatment of cancerous disease. The use of nanoparticles with distinct surface modifications as miRNA vectors permits prolonged bioavailability, high efficacy in tumor targeting, and low toxicity. Nevertheless, the efficacy of miRNA therapy has only been shown in animal models to date.

The role of miRNAs in cutaneous squamous cell carcinoma

MicroRNAs (miRs) are small, noncoding RNAs that negatively regulate gene expressions at posttranscriptional level. Each miR can control hundreds of gene targets and play important roles in various biological and pathological processes such as hematopoiesis, organogenesis, cell apoptosis and proliferation. Aberrant miR expression contributes to initiation and cell progression of cancers. Accumulating studies have found that miRs play a significant role in cutaneous squamous cell carcinoma (cSCC). Deregulations of miRs may contribute to cSCC carcinogenesis is through acting as oncogenic or tumour suppressive miRs. In this study, we summarized the recent data available on cSCC‐associated miRs. In particular, we will discuss the contribution of miR to the initiation and progression of cSCCs. Although there are many obstacles to be overcome, clinical use of miRs as biomarkers for diagnosis, prediction of prognosis and target for therapies, will be a promising area in the future with more expression and functional role of miRs revealed.

Genome-wide screen identified let-7c/miR-99a/miR-125b regulating tumor progression and stem-like properties in cholangiocarcinoma

Cholangiocarcinoma (CCA), which is a poor prognosis malignancy that arises from the malignant transformation of cholangiocytes, is associated with chronic inflammation of the biliary epithelium. Thus far, the molecular mechanisms of the origin and neoplastic processes of CCA that are promoted by inflammation are still unclear and need to be fully elucidated. Here using small RNA sequencing to determine the microRNA (miRNA) expression profiles in CCA, we found that let-7c, miR-99a and miR-125b, which are three miRNAs of the same cluster, were downregulated in CCA and targeted interleukin 6 (IL-6), IL-6R and type 1 insulin-like growth factor, which are important cytokines and receptors of the IL-6/signal transducer and activator 3 (STAT3) pathway and have key roles in inflammation and CCA initiation. We also found that enforced expression of let-7c, miR-99a or miR-125b could reduce the activity of STAT3 and further suppress CCA tumorigenicity in vivo and inhibit the migration and invasion of CCA cells in vitro. Surprisingly, let-7c/miR-99a/miR-125b cluster also significantly decreased the ability of CCA cells for cancer stem cell-like mammosphere generation by downregulating CD133 and CD44, which suggests the pivotal roles of let-7c, miR-99a and miR-125b in CCA by regulating both inflammation and stem-like properties. Our findings showed potential links between miRNAs and inflammation, and provide a potential treatment strategy for developing an miRNA-based therapy via IL-6/STAT3 targeting for CCA.

Clinical implications of epigenetic regulation in oral cancer

Oral cancer is a high incidence cancer which is of major public health concern in India being the most common cancer in males and fifth most common cancer in females in India, contributing to 26% of the global oral cancer burden. The major risk factors of oral cancer are tobacco, alcohol and high risk Human Papilloma Virus type 16/18. However, only 3-12% of the high risk individuals with dysplasia develop oral cancer. Thus, individual genomic variants representing the genomic constitution and epigenetic alterations play a critical role in the development of oral cancer. Extensive epigenetic studies on the molecular lesions including oncogenes, tumor suppressor genes, genes associated with apoptosis, DNA damage repair have been reported. The current review highlights epigenetic regulation with a focus on molecular biomarkers and epidrug therapy in oral cancer. Epigenetic regulation by hypermethylation, histone modifications and specific microRNAs are often associated with early events and advanced stages in oral cancer, and thus indicate epidrug therapy for intervention. The presence of epigenetic marks in oral lesions, cancers and tumor associated mucosa emphasizes indications as biomarkers and epidrugs with therapeutic potential for better patient management.

MiR-125b promotes cell migration and invasion by targeting PPP1CA-Rb signal pathways in gastric cancer, resulting in a poor prognosis

BACKGROUND

MiR-125b functions as an oncogene in many cancers; however, its clinical significance and molecular mechanism in gastric cancers have never been sufficiently investigated. Here, we elucidated the functions and molecular regulated pathways of MiR-125b in gastric cancer.

METHODS

We investigated MiR-125b expression in fresh tissues from 50 gastric cancer patients and 6 gastric cancer cell lines using RT-PCR, and explored its prognostic value by hybridizing MiR-125b in situ for 300 clinical gastric tumor tissues with pathological diagnosis and clinical parameters. The effects of MiR-125b on gastric cancer cells and downstream target genes and proteins were analyzed by MTT, transwell assay, RT-PCR, and western blot on the basis of silencing MiR-125b in vitro. Luciferase reporter plasmid was constructed to demonstrate MiR-125b's direct target.

RESULTS

MiR-125b was upregulated in gastric cancer tissues and cell lines, and significantly promoted cellular proliferation, migration, and invasion by downregulating the expression of PPP1CA and upregulating Rb phosphorylation. MiR-125b expression was significantly correlated with tumor size and depth of invasion, lymph nodes, distant metastasis, and TNM stage. The high-MiR-125b-expression group had a significantly poorer prognosis than the low-expression group (P < 0.05) in stages I, II, and III, and the 5-year survival rate in of the high-expression group was significantly lower than that of the low-expression group.

CONCLUSIONS

MiR-125b functions as an oncogene by targeting downregulated PPP1CA and upregulated Rb phosphorylation in gastric cancer. MiR-125b not only promotes cellular proliferation, migration, and invasion in vitro, but also acts as an independent prognostic factor in gastric cancer.

By promoting cell differentiation, miR-100 sensitizes basal-like breast cancer stem cells to hormonal therapy

Basal-like breast cancer is an aggressive tumor subtype with a poor response to conventional therapies. Tumor formation and relapse are sustained by a cell subset of Breast Cancer Stem Cells (BrCSCs). Here we show that miR-100 inhibits maintenance and expansion of BrCSCs in basal-like cancer through Polo-like kinase1 (Plk1) down-regulation. Moreover, miR-100 favors BrCSC differentiation, converting a basal like phenotype into luminal. It induces the expression of a functional estrogen receptor (ER) and renders basal-like BrCSCs responsive to hormonal therapy. The key role played by miR-100 in breast cancer free-survival is confirmed by the analysis of a cohort of patients' tumors, which shows that low expression of miR-100 is a negative prognostic factor and is associated with gene signatures of high grade undifferentiated tumors. Our findings indicate a new possible therapeutic strategy, which could make aggressive breast cancers responsive to standard treatments.

MiR-429 inhibits oral squamous cell carcinoma growth by targeting ZEB1

BACKGROUND

Oral squamous cell carcinoma (OSCC) is the sixth most common human malignancy worldwide. To develop new therapeutics requires elucidation of the underlying mechanism of OSCC pathogenesis. The role of miR-429 in OSCC remains unknown.

MATERIAL/METHODS

The level of miR-429 and ZEB1 in OSCC tissues and cell lines was measured by qRT-PCR. MiR-429 was down-regulated by miRNAs antisense oligonucleotides (ASO) transfection and up-regulated by miRNAs mimics. Cell proliferation was analyzed by MTT assay. Cell apoptosis was revealed by FACS analysis. Targeted genes were predicted by a bioinformatics algorithm and confirmed by a dual luciferase reporter assay.

RESULTS

MiR-429 was down-regulated in OSCC tissues, and miR-429 overexpression inhibited OSCC cell lines growth and vice versa. Further, we found that miR-429 could inhibit zinc finger E-boxbinding homeobox 1 (ZEB1) expression, and that miR-429 and ZEB1 expression in OSCC tissues were negatively correlated.

CONCLUSIONS

Our data demonstrate the tumor suppressor role of miR-429 in OSCC, and may provide a potential therapeutic target that warrants further investigation.

MicroRNAs in adrenal tumors: relevance for pathogenesis, diagnosis, and therapy

Several lines of evidence support the relevance of microRNAs in both adrenocortical and adrenomedullary (pheochromocytomas) tumors. Significantly differentially expressed microRNAs have been described among benign and malignant adrenocortical tumors and different forms of pheochromocytomas that might affect different pathogenic pathways. MicroRNAs can be exploited as markers of malignancy or disease recurrence. Besides tissue microRNAs, novel data show that microRNAs are released in body fluids, and blood-borne microRNAs can be envisaged as minimally invasive markers of malignancy or prognosis. MicroRNAs might even serve as treatment targets that could expand the rather-limited therapeutic repertoire in the field of adrenal tumors. In this review, we present a critical synopsis of the recent observations made in the field of adrenal tumor-associated microRNAs regarding their pathogenic, diagnostic, and potential therapeutic relevance.

miR-125b can enhance skin tumor initiation and promote malignant progression by repressing differentiation and prolonging cell survival

Zhang et al. show that miR-125b is abundantly expressed, particularly at early stages of malignant progression to squamous cell carcinoma. When elevated in normal murine epidermis, miR-125b promotes tumor initiation and contributes to malignant progression. mir-125b directly represses stress-responsive MAPK genes and indirectly prolongs activated EGFR signaling by repressing Vps4B, encoding a protein implicated in negatively regulating the endosomal sorting complexes that are necessary for the recycling of active EGFR.

Previously, we identified miR-125b as a key regulator of the undifferentiated state of hair follicle stem cells. Here, we show that in both mice and humans, miR-125b is abundantly expressed, particularly at early stages of malignant progression to squamous cell carcinoma (SCC), the second most prevalent cancer worldwide. Moreover, when elevated in normal murine epidermis, miR-125b promotes tumor initiation and contributes to malignant progression. We further show that miR-125b can confer “oncomiR addiction” in early stage malignant progenitors by delaying their differentiation and favoring an SCC cancer stem cell (CSC)-like transcriptional program. To understand how, we systematically identified and validated miR125b targets that are specifically associated with tumors that are dependent on miR-125b. Through molecular and genetic analysis of these targets, we uncovered new insights underlying miR-125b’s oncogenic function. Specifically, we show that, on the one hand, mir-125b directly represses stress-responsive MAP kinase genes and associated signaling. On the other hand, it indirectly prolongs activated (phosphorylated) EGFR signaling by repressing Vps4b (vacuolar protein-sorting 4 homolog B), encoding a protein implicated in negatively regulating the endosomal sorting complexes that are necessary for the recycling of active EGFR. Together, these findings illuminate miR-125b as an important microRNA regulator that is shared between normal skin progenitors and their early malignant counterparts.

The involvement of miR-100 in bladder urothelial carcinogenesis changing the expression levels of mRNA and proteins of genes related to cell proliferation, survival, apoptosis and chromosomal stability

Introduction

MicroRNAs (miRNA) are small non-coding RNAs that play an important role in the control of gene expression by inhibiting protein translation or promoting messenger RNA degradation. Today, miRNAs have been shown to be involved in various physiological and pathological cellular processes, including cancer, where they can act as oncogenes or tumor suppressor genes. Recently, lowered expression of miR-100, resulting in upregulation of FGFR3, has been correlated with low-grade, non-invasive bladder urothelial cancer, as an alternative oncogenesis pathway to the typical FGFR3 gene mutation. Our aim is to analyze the role of miR-100 in bladder cancer cell lines in controlling the expression of some of its possible target genes, including FGFR3 and its relationship with proliferation, apoptosis and DNA ploidy.

Methods

The bladder cancer cell lines RT4 and T24 were transfected with pre-miR 100, anti-miR 100 and their respective controls using a lipid-based formulation. After transfection mRNA and protein levels of its supposed target genes THAP2, BAZ2A, mTOR, SMARCA5 and FGFR3 were analyzed by quantitative real time polymerase chain reaction (qRT-PCR) and western blotting. Cell proliferation, apoptosis and DNA ploidy were analyzed by flow cytometry. For statistical analysis, a t-test was applied, p < 0.05 was considered significant.

Results

After miR-100 transfection, there was a significant reduction in the mRNA of mTOR (p = 0.006), SMARCA5 (p = 0.007) and BAZ2A (p = 0.029) in RT4, mTOR (p = 0.023) and SMARCA5 (p = 0.015) in T24. There was a reduction in the expression of all proteins, variable from 22.5% to 57.1% in both cell lines. In T24 miR-100 promoted an increase in cell proliferation and anti-miR 100 promoted apoptosis characterizing miR-100 as an oncomiR in this cell line representative of a high-grade urothelial carcinoma.

Conclusion

miR-100 transfection reduces expression of BAZ2A, mTOR and SMARCA5 mRNA and protein in BC cell lines. miR-100 would be classified as an oncomiR in T24 cells representative of high grade urothelial carcinoma promoting increase in cell proliferation and reduction in apoptosis. The knowledge of miRNA role in tumors will allow their use as tumor markers and targets for new therapies.

MiRNA in bladder carcinogenesis: A review

Bladder cancer (BC) is the second urological malignancy in incidence, currently being one of the most neoplasms studied with profile and biology poorly defined. In the world, BC is responsible by about 386000 new cases and 150000 deaths annually with considerable economic impact and high costs for health systems. After its discovery more than 20 years, micro RNAs (miRNAs) have been recognized as molecules that work specifically in post-transcriptional control in majority of eukaryote genomes. MiRNAs are a family of small non-coding RNAs of 19-25 nucleotides in length, expressed in a wide variety of organisms, comprising plants, worms and mammals, including humans. They have a fundamental role in physiological and pathological processes in organs and tissues in a context-dependent manner. This review brings new roles of protective and oncogenic miRNAs linked to carcinogenesis of urothelial carcinoma of the bladder, and associated with behavior of disease. Many studies have demonstrated promising roles of miRNAs working as diagnostic and prognostic biomarkers or involved in target therapies, consolidating miRNAs as crucial players in human cancer. This review allowed a reflection about the true functions of miRNAs in bladder carcinogenesis. Not only by their wide capacities of action, but also by abilities in define the cell date. The future of anti-tumor target therapies will be based not in one, but in groups of miRNAs working together in several steps of carcinogenic process, being able to identify the disease, predicting behavior and effectively treat bladder cancer.

MicroRNA100 inhibits self-renewal of breast cancer stem-like cells and breast tumor development

miRNAs are essential for self-renewal and differentiation of normal and malignant stem cells by regulating the expression of key stem cell regulatory genes. Here, we report evidence implicating the miR100 in self-renewal of cancer stem-like cells (CSC). We found that miR100 expression levels relate to the cellular differentiation state, with lowest expression in cells displaying stem cell markers. Utilizing a tetracycline-inducible lentivirus to elevate expression of miR100 in human cells, we found that increasing miR100 levels decreased the production of breast CSCs. This effect was correlated with an inhibition of cancer cell proliferation in vitro and in mouse tumor xenografts due to attenuated expression of the CSC regulatory genes SMARCA5, SMARCD1, and BMPR2. Furthermore, miR100 induction in breast CSCs immediately upon their orthotopic implantation or intracardiac injection completely blocked tumor growth and metastasis formation. Clinically, we observed a significant association between miR100 expression in breast cancer specimens and patient survival. Our results suggest that miR100 is required to direct CSC self-renewal and differentiation.

MicroRNAs - Biology and clinical applications

MicroRNAs are a highly conserved group of small, non-coding RNA molecules, which are 19-25 nucleotides in size. Previously thought to be evolutionary debris with no evident function, these small RNAs have been found to control gene expression primarily by silencing the gene. MicroRNAs are critical to cell physiology and development. They are also implicated in pathological processes such as autoimmune diseases, viral infections and carcinogenesis.

Cardio-miRNAs and onco-miRNAs: circulating miRNA-based diagnostics for non-cancerous and cancerous diseases

Cardiovascular diseases and cancers are the leading causes of morbidity and mortality in the world. MicroRNAs (miRNAs) are short non-coding RNAs that primarily repress target mRNAs. Here, miR-24, miR-125b, miR-195, and miR-214 were selected as representative cardio-miRs that are upregulated in human heart failure. To bridge the gap between miRNA studies in cardiology and oncology, the targets and functions of these miRNAs in cardiovascular diseases and cancers will be reviewed. ACVR1B, BCL2, BIM, eNOS, FGFR3, JPH2, MEN1, MYC, p16, and ST7L are miR-24 targets that have been experimentally validated in human cells. ARID3B, BAK1, BCL2, BMPR1B, ERBB2, FGFR2, IL6R, MUC1, SITR7, Smoothened, STAT3, TET2, and TP53 are representative miR-125b targets. ACVR2A, BCL2, CCND1, E2F3, GLUT3, MYB, RAF1, VEGF, WEE1, and WNT7A are representative miR-195 targets. BCL2L2, ß-catenin, BIM, CADM1, EZH2, FGFR1, NRAS, PTEN, TP53, and TWIST1 are representative miR-214 targets. miR-125b is a good cardio-miR that protects cardiomyocytes; miR-195 is a bad cardio-miR that elicits cardiomyopathy and heart failure; miR-24 and miR-214 are bi-functional cardio-miRs. By contrast, miR-24, miR-125b, miR-195, and miR-214 function as oncogenic or tumor suppressor miRNAs in a cancer (sub)type-dependent manner. Circulating miR-24 is elevated in diabetes, breast cancer and lung cancer. Circulating miR-195 is elevated in acute myocardial infarction, breast cancer, prostate cancer and colorectal adenoma. Circulating miR-125b and miR-214 are elevated in some cancers. Cardio-miRs and onco-miRs bear some similarities in functions and circulation profiles. miRNAs regulate WNT, FGF, Hedgehog and other signaling cascades that are involved in orchestration of embryogenesis and homeostasis as well as pathogenesis of human diseases. Because circulating miRNA profiles are modulated by genetic and environmental factors and are dysregulated by genetic and epigenetic alterations in somatic cells, circulating miRNA association studies (CMASs) within several thousands of cases each for common non-cancerous diseases and major cancers are necessary for miRNA-based diagnostics.

Prognostic marker microRNA-125b inhibits tumorigenic properties of hepatocellular carcinoma cells via suppressing tumorigenic molecule eIF5A2

BACKGROUND

MicroRNAs (miRNAs) belong to a group of small non-coding RNA with differential expression in tumors, including hepatocellular carcinoma (HCC).

AIM

This study investigates the involvement of miR-125b in HCC.

METHODS

Clinical analysis of miR-125b was performed using data derived from miRNA profiling and qPCR. Phenotypic changes of liver cell lines were examined after ectopic miR-125b expression. Lastly, bioinformatics analysis coupled with luciferase reporter assay was used to reveal the cellular target of miR-125b.

RESULTS

A down-regulation of miR-125b was found in HCC tumors and cultured cells. Patients having tumors with ≥twofold reduction in miR-125b compared to adjacent non-tumor tissues contributed to 23 out of 49 HCC cases (46.9 %), while this down-regulation was usually found in patients with tumor venous infiltration and recurrence. miR-125b expression was also negatively correlated with increased serum AFP level and poor overall survival of patients. Ectopic expression of miR-125b led to alleviated tumor phenotypes of HCC cells. Among the 110 bioinformatically predicated candidates, 31 of them negatively correlated with miR-125b in HCC tumors for which one of them named eukaryotic translation initiation factor 5A2 (eIF5A2), known also as a liver oncofetal molecule, was validated to be a direct target of miR-125b in HCC.

CONCLUSIONS

This study has evidenced for the negative correlation of tumor miR-125b expression with poor prognosis of HCC patients. Expression of miR-125b can reverse the tumorigenic properties of cultured HCC cells via suppressing the tumorigenic molecule eIF5A2, thus postulating restoration of miR-125b level as a way to counteract liver tumorigenesis.

Downregulation of microRNA-100 correlates with tumor progression and poor prognosis in colorectal cancer

Dysregulation of microRNA-100 (miR-100) has been shown to be involved in cancer tumorigenesis and progression of several cancer types. However, its expression patterns in tumors are controversial. The aim of this study was to investigate the expression and clinical significance of miR-100 in colorectal cancer (CRC). Quantitative real-time PCR was used to analyze the expression of miR-100 in 138 pairs of human CRC and adjacent normal tissues. The prognostic values of miR-100 in CRC were also analyzed. The results showed that the miR-100 expression was significantly downregulated in CRC tissues when compared to adjacent normal tissues (P<0.001). Also, low miR-100 expression was observed to be significantly correlated with larger tumor size (P=0.023), higher incidence of lymph node metastasis (P=0.009), and advanced TNM stage (P=0.016). More importantly, Kaplan-Meier analysis showed that CRC patients with low miR-100 expression tended to have shorter overall survival. In multivariate analysis stratified for known prognostic variables, low miR-100 expression was identified as an independent prognostic factor for overall survival. In conclusion, our data indicated for the first time that the downregulation of miR-100 was associated with advanced clinical features and poor prognosis of CRC patients, suggesting that miR-100 downregulation may serve as an unfavorable prognostic biomarker in CRC.

Expression profiling of exosomal miRNAs derived from human esophageal cancer cells by Solexa high-throughput sequencing

Cellular genetic materials, such as microRNAs (miRNAs), mRNAs and proteins, are packaged inside exosomes, small membrane vesicles of endocytic origin that are released into the extracellular environment. These cellular genetic materials can be delivered into recipient cells, where they exert their respective biological effects. However, the miRNA profiles and biological functions of exosomes secreted by cancer cells remain unknown. The present study explored the miRNA expression profile and distribution characteristics of exosomes derived from human esophageal cancer cells through Solexa high-throughput sequencing. Results showed that 56,421 (2.94%) unique sequences in cells and 7727 (0.63%) in exosomes matched known miRNAs. A total of 342 and 48 known miRNAs were identified in cells and exosomes, respectively. Moreover, 64 and 32 novel miRNAs were predicted in cells and exosomes, respectively. Significant differences in miRNA expression profiles were found between human esophageal cancer cells and exosomes. These findings provided new insights into the characteristics of miRNAs in exosomes derived from human esophageal cancer cells and the specific roles of miRNAs in intercellular communication mediated by exosomes in esophageal cancer.