miR-31 targets ARID1A and enhances the oncogenicity and stemness of head and neck squamous cell carcinoma

Endometriosis-Associated Ovarian Cancer: From Molecular Pathologies to Clinical Relevance

Endometriosis is a chronic condition affecting reproductive-aged women, characterized by the growth of ectopic endometrial tissue. Despite being benign, endometriosis is associated with an increased risk of certain cancers, including endometriosis-associated ovarian cancer (EAOC). Ovarian cancer is rare, but more common in women with endometriosis, particularly endometrioid and clear-cell carcinomas. Factors such as hormonal imbalance, reproductive history, environmental exposures, and genetic predisposition contribute to the malignant transformation of endometriosis. Thus, understanding potential risk factors causing malignancy is crucial. Over the past few decades, various genetic mutations, microRNAs, as well as tumor microenvironmental factors have been identified, impacting pathways like PI3K/AKT/mTOR, DNA repair mechanisms, oxidative stress, and inflammation. Thus, this review aims to summarize molecular studies involved in EAOC pathogenesis as potential therapeutic targets. However, further research is needed to better understand the molecular and environmental factors driving EAOC development, to target the susceptibility of endometriotic lesions to malignant progression, and to identify effective therapeutic strategies.

[Advances in salivary exosomal miRNAs in head and neck squamous carcinoma]

Salivary exosomes are extracellular vesicles of 30-150 nm in diameter that exist in saliva and play an important role in substance exchange and signal transduction between cells, delivering the lipids, proteins and nucleic acids they carry to the recipient cells and regulating the physiological and pathological processes of the recipient cells. miRNA, as an important "cargo" in exosomes, is transported to the recipient cells and regulates the signaling pathways of the recipient cells, thus playing a regulatory role in disease progression. The miRNAs are transported to the recipient cells and regulate the signaling pathways of the recipient cells, thus playing a regulatory role in the progression of diseases. With the development of technological tools this year, numerous studies have revealed the important role of salivary exosomal miRNAs in the development of head and neck squamous carcinoma and the role of salivary exosomal miRNAs in the diagnosis and treatment of head and neck squamous carcinoma. This paper reviews the occurrence, treatment and prognosis of salivary exosomal miRNA in head and neck squamous carcinoma, and discusses the potential prospects and importance of salivary exosomal miRNA as a biomarker in the diagnosis of head and neck squamous carcinoma.

ARID1A loss is associated with increased NRF2 signaling in human head and neck squamous cell carcinomas

Prior to the next generation sequencing and characterization of the tumor genome landscape, mutations in the SWI/SNF chromatin remodeling complex and the KEAP1-NRF2 signaling pathway were underappreciated. While these two classes of mutations appeared to independently contribute to tumor development, recent reports have demonstrated a mechanistic link between these two regulatory mechanisms in specific cancer types and cell models. In this work, we expand upon these data by exploring the relationship between mutations in BAF and PBAF subunits of the SWI/SNF complex and activation of NRF2 signal transduction across many cancer types. ARID1A/B mutations were strongly associated with NRF2 transcriptional activity in head and neck squamous carcinomas (HNSC). Many additional tumor types showed significant association between NRF2 signaling and mutation of specific components of the SWI/SNF complex. Different effects of BAF and PBAF mutations on the polarity of NRF2 signaling were observed. Overall, our results support a context-dependent functional link between SWI/SNF and NRF2 mutations across human cancers and implicate ARID1A inactivation in HPV-negative HNSC in promoting tumor progression and survival through activation of the KEAP1-NRF2 signaling pathway. The tumor-specific effects of these mutations open a new area of study for how mutations in the KEAP1-NRF2 pathway and the SWI/SNF complex contribute to cancer.

miRNA Expression Profiles in Ovarian Endometriosis and Two Types of Ovarian Cancer-Endometriosis-Associated Ovarian Cancer and High-Grade Ovarian Cancer

Endometriosis-associated ovarian cancer (EOC) consisting of endometrioid cancer and clear-cell ovarian cancer could be promoted by many factors. miRNAs, which are small, non-coding molecules of RNA, are among them. The aim of this study was to detect miRNAs connected with the malignant transformation of endometriosis. FFPE (formalin-fixed, paraffin-embedded) samples of 135 patients operated on for endometriosis and different types of ovarian cancer (EOC and HGSOC-high-grade serous ovarian cancer) were studied. Healthy ovarian tissue was used as a control group. From the expression panel of 754 miRNAs, 7 were chosen for further tests according to their ROC (receiver operating characteristic) curves: miR-1-3p, miR-125b-1-3p, miR-31-3p, miR-200b-3p, miR-502-5p, miR-503-5p and miR-548d-5p. Furthermore, other potentially important clinical data were analysed, which included age, BMI, Ca-125 concentration, miscarriages and deliveries and concomitant diseases such as hypertension, type 2 diabetes and smoking. Among the miRNAs, miR200b-3p had the lowest expression in neoplastic tissues. miR31-3p had the highest expression in women without any lesions in the ovaries. miR-502-5p and miR-548-5p did not differ between the studied groups. The examined miRNA panel generally distinguished significantly normal ovarian tissue and endometriosis, normal ovarian tissue and cancer, and endometriosis and cancer. The malignant transformation of endometriosis is dependent on different factors. miRNA changes are among them. The studied miRNA panel described well the differences between endometriosis and EOC but had no potential to differentiate types of ovarian cancer according to their origin. Therefore, examination of a broader miRNA panel is needed and might prove itself advantageous in clinical practice.

miRNA in head and neck squamous cell carcinomas: promising but still distant future of personalized oncology

Head and neck squamous cell carcinoma is one of the most common and fatal cancers worldwide. Lack of appropriate preventive screening tests, late detection, and high heterogeneity of these tumors are the main reasons for the unsatisfactory effects of therapy and, consequently, unfavorable outcomes for patients. An opportunity to improve the quality of diagnostics and treatment of this group of cancers are microRNAs (miRNAs) - molecules with a great potential both as biomarkers and therapeutic targets. This review aims to present the characteristics of these short non-coding RNAs (ncRNAs) and summarize the current reports on their use in oncology focused on medical strategies tailored to patients' needs.

Non-Coding RNAs in Oral Cancer: Emerging Roles and Clinical Applications

Oral cancer (OC) is among the most prevalent cancers in the world. Certain geographical areas are disproportionately affected by OC cases due to the regional differences in dietary habits, tobacco and alcohol consumption. However, conventional therapeutic methods do not yield satisfying treatment outcomes. Thus, there is an urgent need to understand the disease process and to develop diagnostic and therapeutic strategies for OC. In this review, we discuss the role of various types of ncRNAs in OC, and their promising clinical implications as prognostic or diagnostic markers and therapeutic targets. MicroRNA (miRNA), long ncRNA (lncRNA), circular RNA (circRNA), PIWI-interacting RNA (piRNA), and small nucleolar RNA (snoRNA) are the major ncRNA types whose involvement in OC are emerging. Dysregulated expression of ncRNAs, particularly miRNAs, lncRNAs, and circRNAs, are linked with the initiation, progression, as well as therapy resistance of OC via modulation in a series of cellular pathways through epigenetic, transcriptional, post-transcriptional, and translational modifications. Differential expressions of miRNAs and lncRNAs in blood, saliva or extracellular vesicles have indicated potential diagnostic and prognostic importance. In this review, we have summarized all the promising aspects of ncRNAs in the management of OC.

Genomic landscape and gene expression profiles of feline oral squamous cell carcinoma

Feline oral squamous cell carcinoma (FOSCC) is a cancer of the squamous cell lining in the oral cavity and represents up to 80% of all oral cancers in cats, with a poor prognosis. We have used whole exome sequencing (WES) and RNA sequencing of the tumor to discover somatic mutations and gene expression changes that may be associated with FOSCC occurrence. FOSCC offers a potential comparative model to study human head and neck squamous cell carcinoma (HNSCC) due to its similar spontaneous formation, and morphological and histological features. In this first study using WES to identify somatic mutations in feline cancer, we have identified tumor-associated gene mutations in six cats with FOSCC and found some overlap with identified recurrently mutated genes observed in HNSCC. Four samples each had mutations in TP53, a common mutation in all cancers, but each was unique. Mutations in other cellular growth control genes were also found such as KAT2B and ARID1A. Enrichment analysis of FOSCC gene expression profiles suggests a molecular similarity to human OSCC as well, including alterations in epithelial to mesenchymal transition and IL6/JAK/STAT pathways. In this preliminary study, we present exome and transcriptome results that further our understanding of FOSCC.

Mutual Regulation of ncRNAs and Chromatin Remodeling Complexes in Normal and Pathological Conditions

Chromatin remodeling is the one of the main epigenetic mechanisms of gene expression regulation both in normal cells and in pathological conditions. In recent years, a growing number of investigations have confirmed that epigenetic regulators are tightly connected and form a comprehensive network of regulatory pathways and feedback loops. Genes encoding protein subunits of chromatin remodeling complexes are often mutated and change their expression in diseases, as well as non-coding RNAs (ncRNAs). Moreover, different mechanisms of their mutual regulation have already been described. Further understanding of these processes may help apply their clinical potential for establishment of the diagnosis, prognosis, and treatment of the diseases. The therapeutic targeting of the chromatin structure has many limitations because of the complexity of its regulation, with the involvement of a large number of genes, proteins, non-coding transcripts, and other intermediary molecules. However, several successful strategies have been proposed to target subunits of chromatin remodeling complexes and genes encoding them, as well as the ncRNAs that regulate the operation of these complexes and direct them to the target gene regions. In our review, we focus on chromatin remodeling complexes and ncRNAs, their mutual regulation, role in cellular processes and potential clinical application.

Circulating miRNA as a Biomarker in Oral Cancer Liquid Biopsy

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

Younus P, Venugopal A, Suresh Babu HW, Ajay E, Sanjana M, Arul N, Balachandar V. A new insight into the diverse facets of microRNA-31 in oral squamous cell carcinoma

Background

Micro-RNAs (miRNAs) have been reported as an emerging biomarker in many cancer types. They are used as diagnostic and prognostic biomarkers and could be considered therapeutic targets in treating the same.

Main body

Studies have proven that miRNAs play an essential role in molecular cancer pathophysiology, including oral squamous cell carcinoma. Distinct expression profiles of different miRNAs have been demonstrated in oral squamous cell carcinoma. Among the miRNAs, the miR-31 has strong potential as a unique biomarker in head and neck squamous cell carcinoma, and the increased expression was correlated to a poor clinical outcome with a likely contribution to oral carcinogenesis.

Short conclusion

The recent research on different aspects of miR-31 as a biomarker and also its potential application in the development of therapy for oral squamous cell carcinoma has been focused in this review.

Graphical abstract

A Novel Bayesian Framework Infers Driver Activation States and Reveals Pathway-Oriented Molecular Subtypes in Head and Neck Cancer

Head and neck squamous cell cancer (HNSCC) is an aggressive cancer resulting from heterogeneous causes. To reveal the underlying drivers and signaling mechanisms of different HNSCC tumors, we developed a novel Bayesian framework to identify drivers of individual tumors and infer the states of driver proteins in cellular signaling system in HNSCC tumors. First, we systematically identify causal relationships between somatic genome alterations (SGAs) and differentially expressed genes (DEGs) for each TCGA HNSCC tumor using the tumor-specific causal inference (TCI) model. Then, we generalize the most statistically significant driver SGAs and their regulated DEGs in TCGA HNSCC cohort. Finally, we develop machine learning models that combine genomic and transcriptomic data to infer the protein functional activation states of driver SGAs in tumors, which enable us to represent a tumor in the space of cellular signaling systems. We discovered four mechanism-oriented subtypes of HNSCC, which show distinguished patterns of activation state of HNSCC driver proteins, and importantly, this subtyping is orthogonal to previously reported transcriptomic-based molecular subtyping of HNSCC. Further, our analysis revealed driver proteins that are likely involved in oncogenic processes induced by HPV infection, even though they are not perturbed by genomic alterations in HPV+ tumors.

The meta-signature guided investigation of miRNA candidates as potential biomarkers of oral cancer

OBJECTIVES

This study aimed to experimentally validate dysregulated expression of miRNA candidates selected through updated meta-analysis of most commonly deregulated miRNAs in oral cancer and to explore their diagnostic and prognostic potential.

MATERIALS AND METHODS

Five miRNAs (miR-31-3p, miR-135b-5p, miR-18a-5p, miR-30a-5p, miR-139-5p) from updated meta-signature were selected for validation by qRT-PCR method in 35 oral cancer clinical specimens and adjacent non-cancerous tissue.

RESULTS

Updated meta-analysis has identified 13 most commonly deregulated miRNAs in oral cancer. Seven miRNAs were consistently up-regulated (miR-21-5p, miR-31-3p, miR-135b-5p, miR-31-5p, miR-424-5p, miR-18a-5p, miR-21-3p), while five were down-regulated (miR-139-5p, miR-30a-3p, miR-375-3p, miR-376c-3p, miR-30a-5p). Increased expression of miR-31-3p, miR-135b-5p, as well as decreased expression of miR-139-5p and miR-30a-5p were confirmed in oral cancer compared to adjacent non-cancerous tissue. A three-miRNAs combination (miR-31-3p, miR-139-5p, miR-30a-5p) gave the most promising diagnostic potential for discriminating oral cancer from non-cancerous tissue (AUC: 0.780 (95% CI: 0.673-0.886), p<0.0005, sensitivity 94.3%, specificity 51.4%). High expression of miR-135b-5p, miR-18a-5p and miR-30a-5p was associated with poor survival (p=0.003, p=0.048, p=0.016, respectively).

CONCLUSION

miR-31-3p, miR-139-5p, miR-30a-5p panel was confirmed as a potential diagnostic biomarker when distinguishing oral cancer from non-cancerous tissue. miR-135b-5p, miR-18a-5p and miR-30a-5p might serve as potential biomarkers of poor survival of oral cancer patients.

Salivary miR-31-5p, miR-345-3p, and miR-424-3p Are Reliable Biomarkers in Patients with Oral Squamous Cell Carcinoma

If not detected early, oral squamous cell carcinoma (OSCC) has very poor prognosis, emphasizing the need for reliable early diagnostics. Saliva is considered a promising surrogate biosample for OSCC detection, because it comes into contact with many cells of the tumor mass, providing a comprehensive sampling of tumor-specific biomolecules. Although several protein- and RNA-based salivary biomarkers have been proposed for the detection of OSCC, the results of the studies show large differences. Our goal was to clarify which salivary microRNAs (miRNA) show reliably high expression in the saliva of OSCC patients, to be used as cancer-specific biomarkers, and potentially as early diagnostic biomarkers. Based on a detailed literature search, we selected six miRNAs commonly overexpressed in OSCC, and analyzed their expression in saliva samples of cancer patients and controls by real-time quantitative PCR. Our results suggest that miR-345 and miR-31-5p are consistently upregulated salivary biomarkers for OSCC, and a three-miRNA panel of miR-345, miR-31-5p, and miR-424-3p can distinguish cancer and control patients with high sensitivity.

The Connection between MicroRNAs and Oral Cancer Pathogenesis: Emerging Biomarkers in Oral Cancer Management

Oral cancer is a common human malignancy that still maintains an elevated mortality rate despite scientific progress. Tumorigenesis is driven by altered gene expression patterns of proto-oncogenes and tumor-suppressor genes. MicroRNAs, a class of short non-coding RNAs involved in gene regulation, seem to play important roles in oral cancer development, progression, and tumor microenvironment modulation. As properties of microRNAs render them stable in diverse liquid biopsies, together with their differential expression signature in cancer cells, these features place microRNAs at the top of promising biomarkers for diagnostic and prognostic values. In this review, we highlight eight expression levels and functions of the most relevant microRNAs involved in oral cancer development, progression, and microenvironment sustainability. Furthermore, we emphasize the potential of using these small RNA species as non-invasive biomarkers for the early detection of oral cancerous lesions. Conclusively, we highlight the perspectives and limitations of microRNAs as novel diagnostic tools, as well as therapeutic models.

miR-31-NUMB Cascade Modulates Monocarboxylate Transporters to Increase Oncogenicity and Lactate Production of Oral Carcinoma Cells

Oral squamous cell carcinoma (OSCC) is among the leading causes of cancer-associated death worldwide. miR-31 is an oncogenic miRNA in OSCC. NUMB is an adaptor protein capable of suppressing malignant transformation. Disruption of the miR-31-NUMB regulatory axis has been demonstrated in malignancies. Mitochondrial dysfunction and adaptation to glycolytic respiration are frequent events in malignancies. Monocarboxylate transporters (MCTs) function to facilitate lactate flux in highly glycolytic cells. Upregulation of MCT1 and MCT4 has been shown to be a prognostic factor of OSCC. Here, we reported that miR-31-NUMB can modulate glycolysis in OSCC. Using the CRISPR/Cas9 gene editing strategy, we identified increases in oncogenic phenotypes, MCT1 and MCT4 expression, lactate production, and glycolytic respiration in NUMB-deleted OSCC subclones. Transfection of the Numb1 or Numb4 isoform reversed the oncogenic induction elicited by NUMB deletion. This study also showed, for the first time, that NUMB4 binds MCT1 and MCT4 and that this binding increases their ubiquitination, which may decrease their abundance in cell lysates. The disruptions in oncogenicity and metabolism associated with miR-31 deletion and NUMB deletion were partially rescued by MCT1/MCT4 expression or knockdown. This study demonstrated that NUMB is a novel binding partner of MCT1 and MCT4 and that the miR-31-NUMB-MCT1/MCT4 regulatory cascade is present in oral carcinoma.

MicroRNAs regulating SOX2 in cancer progression and therapy response

The proliferation, metastasis and therapy response of tumour cells are tightly regulated by interaction among various signalling networks. The microRNAs (miRNAs) can bind to 3'-UTR of mRNA and down-regulate expression of target gene. The miRNAs target various molecular pathways in regulating biological events such as apoptosis, differentiation, angiogenesis and migration. The aberrant expression of miRNAs occurs in cancers and they have both tumour-suppressor and tumour-promoting functions. On the contrary, SOX proteins are capable of binding to DNA and regulating gene expression. SOX2 is a well-known member of SOX family that its overexpression in different cancers to ensure progression and stemness. The present review focuses on modulatory impact of miRNAs on SOX2 in affecting growth, migration and therapy response of cancers. The lncRNAs and circRNAs can function as upstream mediators of miRNA/SOX2 axis in cancers. In addition, NF-κB, TNF-α and SOX17 are among other molecular pathways regulating miRNA/SOX2 axis in cancer. Noteworthy, anti-cancer compounds including bufalin and ovatodiolide are suggested to regulate miRNA/SOX2 axis in cancers. The translation of current findings to clinical course can pave the way to effective treatment of cancer patients and improve their prognosis.

LncRNA MIR31HG Drives Oncogenicity by Inhibiting the Limb-Bud and Heart Development Gene (LBH) during Oral Carcinoma

The miR-31 host gene (MIR31HG) encodes a long non-coding RNA (LncRNA) that harbors miR-31 in its intron 2; miR-31 promotes malignant neoplastic progression. Overexpression of MIR31HG and of miR-31 occurs during oral squamous cell carcinoma (OSCC). However, the downstream effectors modulated by MIR31HG during OSCC pathogenesis remain unclear. The present study identifies up-regulation of MIR31HG expression during the potentially premalignant disorder stage of oral carcinogenesis. The potential of MIR31HG to enhance oncogenicity and to activate Wnt and FAK was identified when there was exogenous MIR31HG expression in OSCC cells. Furthermore, OSCC cell subclones with MIR31HG deleted were established using a Crispr/Cas9 strategy. RNA sequencing data obtained from cells expressing MIR31HG, cells with MIR31HG deleted and cells with miR-31 deleted identified 17 candidate genes that seem to be modulated by MIR31HG in OSCC cells. A TCGA database algorithm pinpointed MMP1, BMP2 and Limb-Bud and Heart development (LBH) as effector genes controlled by MIR31HG during OSCC. Exogenous LBH expression decreases tumor cell invasiveness, while knockdown of LBH reverses the oncogenic suppression present in MIR31HG deletion subclones. The study provides novel insights demonstrating the contribution of the MIR31HG-LBH cascade to oral carcinogenesis.

Endothelial Progenitor Cells Dysfunctions and Cardiometabolic Disorders: From Mechanisms to Therapeutic Approaches

Metabolic syndrome (MetS) is a cluster of several disorders, such as hypertension, central obesity, dyslipidemia, hyperglycemia, insulin resistance and non-alcoholic fatty liver disease. Despite health policies based on the promotion of physical exercise, the reduction of calorie intake and the consumption of healthy food, there is still a global rise in the incidence and prevalence of MetS in the world. This phenomenon can partly be explained by the fact that adverse events in the perinatal period can increase the susceptibility to develop cardiometabolic diseases in adulthood. Individuals born after intrauterine growth restriction (IUGR) are particularly at risk of developing cardiovascular diseases (CVD) and metabolic disorders later in life. It has been shown that alterations in the structural and functional integrity of the endothelium can lead to the development of cardiometabolic diseases. The endothelial progenitor cells (EPCs) are circulating components of the endothelium playing a major role in vascular homeostasis. An association has been found between the maintenance of endothelial structure and function by EPCs and their ability to differentiate and repair damaged endothelial tissue. In this narrative review, we explore the alterations of EPCs observed in individuals with cardiometabolic disorders, describe some mechanisms related to such dysfunction and propose some therapeutical approaches to reverse the EPCs dysfunction.

Aberrant Expression of microRNA Clusters in Head and Neck Cancer Development and Progression: Current and Future Translational Impacts

MicroRNAs are small non-coding RNAs known to negative regulate endogenous genes. Some microRNAs have high sequence conservation and localize as clusters in the genome. Their coordination is regulated by simple genetic and epigenetic events mechanism. In cells, single microRNAs can regulate multiple genes and microRNA clusters contain multiple microRNAs. MicroRNAs can be differentially expressed and act as oncogenic or tumor suppressor microRNAs, which are based on the roles of microRNA-regulated genes. It is vital to understand their effects, regulation, and various biological functions under both normal and disease conditions. Head and neck squamous cell carcinomas are some of the leading causes of cancer-related deaths worldwide and are regulated by many factors, including the dysregulation of microRNAs and their clusters. In disease stages, microRNA clusters can potentially control every field of oncogenic function, including growth, proliferation, apoptosis, migration, and intercellular commutation. Furthermore, microRNA clusters are regulated by genetic mutations or translocations, transcription factors, and epigenetic modifications. Additionally, microRNA clusters harbor the potential to act therapeutically against cancer in the future. Here, we review recent advances in microRNA cluster research, especially relative to head and neck cancers, and discuss their regulation and biological functions under pathological conditions as well as translational applications.

microRNAs deregulation in head and neck squamous cell carcinoma

Head and neck (HN) squamous cell carcinoma (SCC) is the eighth most common human cancer worldwide. Besides tobacco and alcohol consumption, genetic and epigenetic alterations play an important role in HNSCC occurrence and progression. microRNAs (miRNAs) are small noncoding RNAs that regulate cell cycle, proliferation, development, differentiation, and apoptosis by interfering in gene expression. Expression profiling of miRNAs showed that some miRNAs are upregulated or downregulated in tumor cells when compared with the normal cells. The present review focuses on the role of miRNAs deregulations in HNSCC, enrolled in risk, development, outcome, and therapy sensitivity. Moreover, the influence of single nucleotide variants in miRNAs target sites, miRNAs seed sites, and miRNAs-processing genes in HNSCC was also revised. Due to its potential for cancer diagnosis, progression, and as a therapeutic target, miRNAs may bring new perspectives in HNSCC understanding and therapy, especially for those patients with no or insufficient treatment options.

MicroRNA profile in the squamous cell carcinoma: prognostic and diagnostic roles

Head and neck squamous cell carcinomas (HNSCCs) are human malignancies associated with both genetic and environmental factors. MicroRNAs (miRNAs) as a group of small non-coding RNAs have prominent roles in the development of this kind of cancer. Expressions of several miRNAs have been demonstrated to be increased in HNSCC samples vs. non-malignant tissues. In silico prediction tools and functional analyses have confirmed the function of some miRNAs in the modulation of cancer-associated targets, thus indicating these miRNAs as onco-miRs. Moreover, numerous miRNAs have been down-regulated in HNSCC samples. Their targets mostly enhance cell proliferation or inhibit apoptosis. miRNAs signature has practical implications in the diagnosis, staging, and management of HNSC. Most notably, numerous miRNAs have been shown to alter response of tumor cells to anti-cancer drugs such as cisplatin and doxorubicin. Circulating levels of these small transcripts have been suggested as promising biomarkers for diagnosis of HNSCC. In the present manuscript, we sum up the available literature regarding the miRNAs signature in HNSCC and their role as diagnostic/prognostic biomarkers.

Remodeling of the ARID1A tumor suppressor

In recent years, AT-rich interactive domain-containing protein 1A (ARID1A) has been widely accepted as a bona fide tumor suppressor due to its essential role in preventing tumorigenesis and tumor progression in both mouse and human contexts. ARID1A shows high mutation frequencies in both cancers and preneoplastic lesions. The loss of ARID1A expression in cancer cells leads to increases in cell proliferation, invasion and migration and reductions in cell apoptosis and chemosensitivity. The tumor-suppressive role of ARID1A is mainly attributed to its regulation of gene transcription, which can be induced either directly by chromatin remodeling or indirectly by affecting histone modifications. ARID1A also acts independently of its cardinal transcription-regulating mechanisms, which include interfering with protein-protein interactions. Interestingly, nonmutational mechanisms, such as regulation by DNA hypermethylation, microRNAs, and ubiquitinases/deubiquitinases, have provided another perspective on ARID1A inactivation in cancer. Since the critical tumor-suppressive role of ARID1A has been revealed, several studies have attempted to identify synthetic lethal targets with ARID1A mutation/inactivation as an alternative strategy for cancer treatment.

The roles of microRNAs in the stemness of oral cancer cells

Oral cancer (OC), which is the most common form of head and neck cancers, has one of the lowest (~50%) overall 5-year survival rates. The main reasons for this high mortality rate are diagnosis of OC in advanced stages in most patients and spread to distant organs via lymph node metastasis. Many studies have shown that a small population of cells within the tumor plays vital roles in the initiation, progression, and metastasis of the tumor, resistance to chemotherapeutic agents, and recurrence. These cells, identified as cancer stem cells (CSCs), are the main reasons for the failure of current treatment modalities. Deregulated expressions of microRNAs are closely related to tumor prognosis, metastasis and drug resistance. In addition, microRNAs play important roles in regulating the functions of CSCs. Until now, the roles of microRNAs in the acquisition and maintenance of OC stemness have not been elucidated in detail yet. Here in this review, we summarized significant findings and the latest literature to better understand the involvement of CSCs in association with dysregulated microRNAs in oral carcinogenesis. Possible roles of these microRNAs in acquisition and maintenance of CSCs features during OC pathogenesis were summarized.

Decreased lncRNA, TINCR, promotes growth of colorectal carcinoma through upregulating microRNA-31

Abnormal expression in terminal differentiation-induced noncoding RNA (TINCR), a long non-coding RNA (lncRNA), has been reported in different human cancers, including colorectal carcinoma (CRC). Moreover, the molecular mechanisms that underlie the effects of TINCR on CRC remain unclear. Here, by a set of bioinformatics studies, we found that microRNA-31 (miR-31), the oncogenic miRNA that robustly upregulates in CRC, was a sponge miRNA for TINCR. TINCR and miR-31 levels were inversely correlated in both CRC tissues and CRC cell lines. Luciferase reporter assay revealed a specific binding site on TINCR for miR-31. Suppression of TINCR promoted CRC cell growth and migration in vitro, while overexpression of TINCR inhibited CRC cell growth and migration in vitro. TINCR depletion increased tumor xenograft growth in vivo, while TINCR overexpression inhibited it. Together, our study suggests that re-expressing TINCR may suppress invasive outgrowth of CRC through miR-31.

Expression of NANOG and Its Regulation in Oral Squamous Cell Carcinoma

Background

Results of previous studies suggest that NANOG may be an important prognostic biomarker in oral squamous cell carcinoma (OSCC), but there are contradictory results regarding NANOG expression patterns on mRNA and protein levels, and the mechanisms of its regulation are poorly understood. Our aim was to analyze the expression and diagnostic significance of NANOG in OSCC, and the possible mechanisms of its regulation, i.e., protein regulators on mRNA level (OCT4, SOX2, KLF4, AGR2, and NOTCH1), methylation status, copy number variation, and regulatory miRNAs, miR-145, miR-335, miR-150, miR-34a, miR-128, and miR-27a.

Methods

Our study included 120 patients with OSCC. Expression of NANOG protein and mRNA was analyzed using immunohistochemistry and qPCR. Expression of regulatory factors, miRNAs, and copy number variation was performed using qPCR. Methylation status of NANOG promoter was determined using PCR and Sanger sequencing.

Results

We detected upregulation of NANOG and OCT4 and downregulation of NOTCH1 and AGR2 mRNA in OSCC with lymph node metastases compared to OSCC without lymph node metastases. We observed a strong positive correlation between mRNAs of NANOG and those of its protein regulators OCT4, SOX2, NOTCH1, AGR2, and KLF4. The expression of NANOG was in positive correlation with the expression of miR-34a. There was also a correlation between T status of OSCC and the expression of miR-335 and miR-150 and a correlation of miR-150 with the N status of T2 OSCC. NANOG promoter methylation and copy number variation were only observed in a small proportion of samples.

Conclusions

Our findings confirm the diagnostic significance of NANOG in OSCC and provide information on NANOG expression patterns on both mRNA and protein levels. They also suggest that protein regulators and microRNAs might play a crucial role, whereas methylation of its promoter and copy number variation probably have a minor role in the regulation of NANOG expression in OSCC.

Epigenetic Modifications in Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common human malignancy in the world, with high mortality and poor prognosis for patients. Among the risk factors are tobacco and alcohol intake, human papilloma virus, and also genetic and epigenetic modifications. Many studies show that epigenetic events play an important role in HNSCC development and progression, including DNA methylation, chromatin remodeling, histone posttranslational covalent modifications, and effects of non-coding RNA. Epigenetic modifications may influence silencing of tumor suppressor genes by promoter hypermethylation, regulate transcription by microRNAs and changes in chromatin structure, or induce genome instability through hypomethylation. Moreover, getting to better understand aberrant patterns of methylation may provide biomarkers for early detection and diagnosis, while knowledge about target genes of microRNAs may improve the therapy of HNSCC and extend overall survival. The aim of this review is to present recent studies which demonstrate the role of epigenetic regulation in the development of HNSCC.

Overexpression of the Oral Mucosa-Specific microRNA-31 Promotes Skin Wound Closure

Wounds within the oral mucosa are known to heal more rapidly than skin wounds. Recent studies suggest that differences in the microRNAome profiles may underlie the exceptional healing that occurs in oral mucosa. Here, we test whether skin wound-healing can be accelerating by increasing the levels of oral mucosa-specific microRNAs. A panel of 57 differentially expressed high expresser microRNAs were identified based on our previously published miR-seq dataset of paired skin and oral mucosal wound-healing [Sci. Rep. (2019) 9:7160]. These microRNAs were further grouped into 5 clusters based on their expression patterns, and their differential expression was confirmed by TaqMan-based quantification of LCM-captured epithelial cells from the wound edges. Of these 5 clusters, Cluster IV (consisting of 8 microRNAs, including miR-31) is most intriguing due to its tissue-specific expression pattern and temporal changes during wound-healing. The in vitro functional assays show that ectopic transfection of miR-31 consistently enhanced keratinocyte proliferation and migration. In vivo, miR-31 mimic treatment led to a statistically significant acceleration of wound closure. Our results demonstrate that wound-healing can be enhanced in skin through the overexpression of microRNAs that are highly expressed in the privileged healing response of the oral mucosa.

Loss of ARID1A Expression Correlates With Tumor Differentiation and Tumor Progression Stage in Pancreatic Ductal Adenocarcinoma

Mutations in the AT-rich interactive domain 1A gene, which encodes a subunit of the Switch/Sucrose nonfermentable chromatin remodeling complex, can result in loss of protein expression and are associated with different cancers. Here, we used immunohistochemistry to investigate the significance of AT-rich interactive domain 1A loss in 73 pancreatic ductal adenocarcinoma cases with paired paracancerous normal pancreatic tissues. The relationship between levels of the AT-rich interactive domain 1A protein product, BAF250a, and clinicopathological parameters in the 73 pancreatic cancer specimens was also analyzed. We found that the expression of AT-rich interactive domain 1A in normal pancreatic tissue was higher than that in tumor tissue. Loss of AT-rich interactive domain 1A expression in pancreatic tumors was associated with tumor differentiation (P = .002) and tumor stage (P = .048). Meanwhile, BAF250a protein levels were not related to lymph node metastasis, distant metastasis, sex, or age and were not associated with survival. Transfection of the pancreatic cancer cell lines AsPC-1 and PANC-1 with small-interfering RNA specific for AT-rich interactive domain 1A resulted in elevated messenger RNA and protein expression levels of B-cell lymphoma-2 (Bcl-2), CyclinD1, and Kirsten rat sarcoma viral oncogene (KRAS). The AT-rich interactive domain 1A expression level in the cells was increased following microRNA-31 (miR-31) inhibitor transfection. Our data provide additional evidence that AT-rich interactive domain 1A might function as a tumor suppressor gene in pancreatic carcinogenesis.

A Study on the Correlations of the miR-31 Expression with the Pathogenesis and Prognosis of Head and Neck Squamous Cell Carcinoma

OBJECTIVE

To investigate the correlations of miR-31 expression with cell proliferation, invasion, and prognosis of patients with head and neck squamous cell carcinoma (HNSCC).

METHODS

The expression of miR-31 in human laryngeal cancer TU686 cells, human nasopharyngeal carcinoma CNE-2 cells, and normal human oral keratinocyte (NHOK) epithelial cells was detected via quantitative real-time polymerase chain reaction (qRT-PCR). The effects of miR-31 on the proliferation and invasion of HNSCC cells were explored through transfecting miR-31 analogs (miR-31 mimics) and miR-31 inhibitors (anti-miR-31). qRT-PCR was applied to detect the expressions of miR-31 in 56 cases of HNSCC tumor tissues and tumor-adjacent normal tissues. The correlation of miR-31 expression with pathological parameters and survival prognosis of HNSCC patients was also analyzed.

RESULTS

The expressions of miR-31 in TU686 and CNE-2 cell lines were significantly higher than that in NHOK cells (p < 0.01). Compared with those in the negative control group, the proliferation and invasion abilities of cells transfected with miR-31 mimics were notably enhanced (p < 0.01), and those of cells transfected with anti-miR-31 were significantly reduced (p < 0.01). In addition, miR-31 mimics significantly reduced ARID1A expression (p < 0.01) and anti-miR-31 increased its expression (p < 0.05). The expression of miR-31 in tumor tissues of HNSCC patients was remarkably higher than that in tumor-adjacent normal tissues (p < 0.01). This, together with clinical data analysis, revealed that the expression of miR-31 was associated with tumor differentiation, metastasis, and staging of patients, and the survival period of patients with lowly expressed miR-31 was longer.

CONCLUSIONS

The highly expressed miR-31 can stimulate the proliferation and invasion of HNSCC cells, closely correlated with tumor differentiation, metastasis, and staging of patients. Patients with lowly expressed miR-31 have a longer survival period. Therefore, miR-31 expression can be taken as a crucial reference indicator for the prognosis of HNSCC patients.

MiR-31 is a potential biomarker for diagnosis of head and neck squamous cell carcinoma

MicroRNAs (miRNAs) play important roles in the development of head and neck squamous cell carcinoma (HNSCC). However, their potential clinical value as biomarkers remains poorly known. The aim of this study was to assess the association between tissue/serum miR-31 expression levels and prognosis of HNSCC. In this clinical study, tumor samples were obtained from 118 patients with HNSCC and 48 patients with oral epithelial dysplasia, and blood samples were collected from all the HNSCC cases and 60 normal controls. The expression levels of tissue/serum miR-31 were measured by real-time PCR. Chi-square test was used to evaluate the correlation between tissue/serum miR-31 and clinical parameters of HNSCC. Survival curves were constructed using the Kaplan-Meier method and log-rank test. Multivariate Cox regression analyses were used to estimate independent predictors of survival for HNSCC. Our findings showed that tissue miR-31 levels in HNSCC tumor specimens exhibited higher than that in oral epithelial dysplasia samples and normal tissues. Oral epithelial dysplasia with higher expression of miR-31 was more prone to progress into HNSCC. Likewise, serum miR-31 expression in HNSCC patients was markedly increased in compared to normal controls. Moreover, serum miR-31 performed well to distinguish HNSCC subjects from controls. In addition, increased tissue/serum miR-31 expression was positively correlated with poor clinical variables and dismal prognosis. Finally, tissue miR-31 was confirmed to be an independent prognostic factor for HNSCC. Taken together, miR-31 had strong potential as a promising biomarker in HNSCC detection.

Predicting the Presence of Oral Squamous Cell Carcinoma Using Commonly Dysregulated MicroRNA in Oral Swirls

Oral swirls are a noninvasive, rapidly collected source of salivary microRNA (miRNA) potentially useful in the early detection of disease states, particularly oral squamous cell carcinoma (OSCC). The aim of this study was to predict the presence of OSCC using a panel of OSCC-related dysregulated miRNA found in oral swirls, identified jointly in data from formalin-fixed paraffin-embedded (FFPE) and fresh-frozen specimens. Next-generation sequencing (NGS) was used to determine miRNA fold changes in FFPE OSCC specimens relative to histologically normal epithelium. These data were placed with NGS of fresh-frozen tissue data of The Cancer Genome Atlas database to select a panel of commonly dysregulated miRNA. This panel was then analyzed by RT-qPCR in RNA extracted from oral swirls collected from 30 patients with OSCC and 30 controls. Upregulation of miR-31 and miR-21 and downregulation of miR-99a, let-7c, miR-125b, and miR-100 were found between OSCC and controls in both FFPE and fresh-frozen samples. These miRNAs were studied in a training set of 15 OSCC versus 15 control oral swirls to develop a dysregulation score [AUC, 0.95; 95% confidence interval (CI), 0.88-1.03] and classification tree. A test cohort of 15 OSCC versus 15 control oral swirls yielded a dysregulation score AUC of 0.86 (95% CI, 0.79-1.00) with the classification tree identifying 100% (15/15) of OSCC and 67% (10/15) of controls. This study debuts the use of OSCC-associated miRNA, commonly dysregulated in both FFPE and frozen specimens, in oral swirls to indicate the presence of OSCC with high accuracy. Cancer Prev Res; 11(8); 491-502. ©2018 AACR.

Cigarette smoke and chewing tobacco alter expression of different sets of miRNAs in oral keratinocytes

Carcinogenic effect of tobacco in oral cancer is through chewing and/or smoking. Significant differences exist in development of oral cancer between tobacco users and non-users. However, molecular alterations induced by different forms of tobacco are yet to be fully elucidated. We developed cellular models of chronic exposure to chewing tobacco and cigarette smoke using immortalized oral keratinocytes. Chronic exposure to tobacco resulted in increased cell scattering and invasiveness in immortalized oral keratinocytes. miRNA sequencing using Illumina HiSeq 2500 resulted in the identification of 10 significantly dysregulated miRNAs (4 fold; p ≤ 0.05) in chewing tobacco treated cells and 6 in cigarette smoke exposed cells. We integrated this data with global proteomic data and identified 36 protein targets that showed inverse expression pattern in chewing tobacco treated cells and 16 protein targets that showed inverse expression in smoke exposed cells. In addition, we identified 6 novel miRNAs in chewing tobacco treated cells and 18 novel miRNAs in smoke exposed cells. Integrative analysis of dysregulated miRNAs and their targets indicates that signaling mechanisms leading to oncogenic transformation are distinct between both forms of tobacco. Our study demonstrates alterations in miRNA expression in oral cells in response to two frequently used forms of tobacco.

MiR-31 regulates the function of diabetic endothelial progenitor cells by targeting Satb2

Endothelial malfunctions in patients with diabetes are known to result in vascular diseases, and endothelial progenitor cells (EPCs) are indispensable for the functional preservation of the vascular endothelium. MicroRNA-31 (miR-31) has been found to be able to modulate the differentiation of stem cells. However, it is still unclear how miR-31 functions in diabetic EPCs. The aim of this study was to investigate how miR-31 regulates diabetic EPC function. In the current study, miR-31 expression was compared between normal and diabetic EPCs. Satb2 was recognized as a functionally related target of miR-31 in EPCs according to computational prediction. We also explored the role of miR-31 in terms of its anti-apoptotic effects. A remarkable elevation in miR-31 expression was found in diabetic EPCs, and this elevated expression resulted in suppressed cell proliferation under high glucose. It was also found that miR-31 targets Satb2, leading to the anti-apoptotic effect and maintenance of the functions of EPCs. Furthermore, knockdown of Satb2 exhibited an inhibitory effect on proliferation and migration of EPCs in both healthy and diabetic subjects, which showed the same trend as miR-31 overexpression. Conversely, overexpression of Satb2 showed the opposite effect. Moreover, overexpression of Satb2 attenuated the miR-31-induced migration and colony-forming ability reduction and apoptosis induction of EPCs in both healthy and diabetic subjects. In diabetic EPCs, elevated glucose level was found to up-regulate miR-31 expression, which in turn enhanced the malfunction and death of EPCs. In conclusion, our results indicate that up-regulation of miR-31 may underlie endothelial dysfunction in diabetes by targeting Satb2.

Targeting of miR-31/96/182 to the Numb gene during head and neck oncogenesis

BACKGROUND

MicroRNAs (miRNAs) play crucial roles in head and neck squamous cell carcinoma (HNSCC). This study investigates whether miR-31, miR-96, and miR-182 are involved in targeting Numb during HNSCC.

METHODS

The expression of miR-31/96/182 in tumor tissues was analyzed. Reporter assay, knockdown, expression, and oncogenic analysis were carried out in cell lines.

RESULTS

Upregulation of miR-31/96/182 was detected in tumor tissues. In addition, advanced tumors showed higher expression levels of these miRNAs. The expression of these miRNAs was upregulated after treatment with areca ingredients (P < .01 or P < .001). These miRNAs directly targeted the 3' untranslated region (UTR) sequence of the Numb gene. An increased migration and invasion of HNSCC cells was associated with the exogenous expression of miR-31/96/182 (P < .01 or P < .001), and this was reverted by expression of Numb.

CONCLUSION

This study provides new evidence demonstrating that there is frequent and concordant upregulation of miR-31, miR-96, and miR-182 during HNSCC and these miRNAs co-target Numb.

Circulating miR-31 as an effective biomarker for detection and prognosis of human cancer: a meta-analysis

PURPOSE

Circulating miR-31 was found to be associated with cancers detection and prognosis. The present meta-analysis aimed to explore the effect of circulating miR-31 on cancer detection and prognosis.

METHOD

The studies were accessed using multiple databases. RevMan5.3, Meta-DiSc 1.4, and STATA14.0 were used to estimate the pooled effects, heterogeneity among studies, and publication bias.

RESULTS

A total of 14 studies with 1397 cancer patients and 1039 controls were included. For the 12 prognostic tests, the adjusted pooled-AUC was 0.79 (95% CI: 0.73-0.86) as the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odd ratio (DOR) from 10 tests was 0.79 (95% CI: 0.76-0.82), 0.79 (95% CI: 0.76-0.82), 3.81 (95% CI: 2.90-5.01), 0.26 (95% CI: 0.20-0.35), and 16.81 (95% CI: 9.67-29.25), respectively. For the 5 prognosis analyses, the pooled HR (hazard ratio) of overall survival (OS) was 1.55 (95% CI 1.30-1.86) for high versus low circulating miR-31 expression. However, high expression of circulating miR-31 did not significantly increase the risk of poor differentiation (pooled OR=1.39, 95% CI: 0.56-3.47) and LNM (pooled OR=3.46, 95% CI: 0.96-12.42) in lung cancer.

CONCLUSION

Circulating miR-31 is an effective biomarker and could be used as a component of miRs signature for cancer detection and prognosis surveillance.

Tissue and serum microRNA profile of oral squamous cell carcinoma patients

Head and neck cancer is characterized by malignant tumors arising from the epithelium covering the upper aerodigestive tract, and the majority of these epithelial malignancies are squamous cell carcinomas (SCCs) of the oral cavity (OSCCs). The aim of the current work was to identify miRNAs regulated in OSCC cancerous tissue when compared to a healthy adjacent tissue and to verify the presence of the same miRNAs in the circulation of these patients. For that serum samples and biopsies of healthy and tumor tissues were collected from five patients diagnosed with OSCC of the oral cavity, RNA was extracted from these samples and microRNAs libraries were prepared and sequenced. A total 255 miRNAs were identified in tissue and 381 different miRNAs were identified in serum samples. When comparing the miRNA expression between tumor and healthy tissue we identified 48 miRNAs (25 down- and 23 up-regulated) that were differentially expressed (FDR < 0.05). From these 48 differentially expressed miRNAs in tissue, 30 miRNAs were also found in the serum of the same patients. hsa-miR-32-5p was up-regulated in tumor compared to healthy tissue in our study, and was previously shown to be up-regulated in the serum of OSCC patients. Therefore, this suggests that miRNAs can be used as potential non-invasive biomarkers of OSCC.

MiR-31-5p-ACOX1 Axis Enhances Tumorigenic Fitness in Oral Squamous Cell Carcinoma Via the Promigratory Prostaglandin E2

During neoplastic development, a multitude of changes in genome-encoded information are progressively selected to confer growth and survival advantages to tumor cells. microRNAs-mRNAs regulatory networks, given their role as a critical layer of robust gene expression control, are frequently altered in neoplasm. However, whether and how these gene perturbations impact metabolic homeostasis remains largely unresolved.

Methods: Through targeted miRNA expression screening, we uncovered an oral squamous cell carcinoma (OSCC)-associated miRNAome, among which miR-31-5p was identified based on extent of up-regulation, functional impact on OSCC cell migration and invasion, and direct regulation of the rate-limiting enzyme in peroxisomal β-oxidation, ACOX1.

Results: We further found that both miR-31-5p and ACOX1 underpin, in an antagonistic manner, the overall cellular lipidome profiles as well as the migratory and invasive abilities of OSCC cells. Interestingly, the extracellular levels of prostaglandin E2 (PGE2), a key substrate of ACOX1, were controlled by the miR-31-5p-ACOX1 axis, and were shown to positively influence the extent of cell motility in correlation with metastatic status. The promigratory effect of this metabolite was mediated by an elevation in EP1-ERK-MMP9 signaling. Of note, functional significance of this regulatory pathway was further corroborated by its clinicopathologically-correlated expression in OSCC patient specimens.

Conclusions: Collectively, our findings outlined a model whereby misregulated miR-31-5p-ACOX1 axis in tumor alters lipid metabolomes, consequently eliciting an intracellular signaling change to enhance cell motility. Our clinical analysis also unveiled PGE2 as a viable salivary biomarker for prognosticating oral cancer progression, further underscoring the importance of lipid metabolism in tumorigenesis.

miR-31 and miR-145 as Potential Non-Invasive Regulatory Biomarkers in Patients with Endometriosis

Objective

Endometriosis is a prevalent gynecologic disease affecting 10% of women in reproductive age. Endometriosis is diagnosed by laparoscopy that was followed by histologic confirmation. Early diagnosis will lead to a more effective treatment with much less morbidity. As miR-31 and miR-145 are shown to be directly or indirectly correlated to biological processes involved in endometriosis, the aim of this study was to examine the association of miR-31 and miR-145 expression in plasma with the presence of endometriosis.

Materials and Methods

In this case control study, the plasma samples of 55 patients with endometriosis and 23 women without endometriosis were collected, extracted and analyzed by real time quantitative polymerase chain reaction (qPCR) for the expression of miR-145 and miR-31.

Results

Our findings showed that miR-31 expression levels in stage 3 or 4 and stage 1 or 2 were significantly down- regulated (less than 0.01-fold, P<0.05), while the expression level of miR-145 was significantly up-regulated in women with endometriosis in stage 1 or 2.

Conclusion

Different cellular biological processes, such as differentiation, proliferation, mitochondrial function, reactive oxygen species (ROS) production, invasion and decidualization, are deregulated in endometriosis. miR-31 and miR-145 are microRNAs (miRNAs) with potential roles, as shown in pathologies like cancers. We found that miR- 31 was under-expressed in patients with endometriosis, while miR-145 was over-expressed in stage 1 or 2, indicating that they were relatively down-regulated in the more severe forms. Our findings suggested that these two miRNAs may be considered as potential biomarkers with probable implications in early diagnosis and even follow-up of patients with endometriosis.

A novel strategy to dissect endogenous gene transcriptional regulation in live cells

Gene transcription is a central tenet of biology, traditionally measured by RT-PCR, microarray, or more recently, RNA sequencing. However, these measurements only provide a snapshot of the state of gene transcription and only represent an overall readout of complex transcriptional networks that regulate gene expression. In this report, we describe a novel strategy to dissect endogenous gene transcription regulation in live cells by knocking in a reporter gene, EGFP, under the control of the endogenous gene promoter, using the ARID1A gene as an example. The ARID1A gene, encoding a subunit of the ATP-dependent chromatin remodeling complex SNF/SWI, has recently been identified as a tumor suppressor in multiple cancers. Despite studies that elucidate the mechanism of ARID1A's tumor suppressor function, little is known of the genes/events that regulate ARID1A expression. Using the HEK293 cells as a model, we discovered novel aspects of ARID1A transcription regulation in response to cell cycle progression, DNA damage, and microRNAs, exemplifying the potential of our strategy in providing new insight to the mechanism of gene transcription regulation. This strategy can be generalized to essentially any gene of interest, making it a powerful tool for the study of gene expression heterogeneity, especially in cancer cells, and a robust readout for high-throughput screening of agents that modulate gene transcription.

Klf4 inhibits tumor growth and metastasis by targeting microRNA-31 in human hepatocellular carcinoma

MicroRNAs (miRNAs or miRs) are short, endogenous non-coding RNA molecules, demonstrating abnormal expression in cancer initiation and progression. In this study, we profiled 18 differentially regulated miRNAs, including miRNA-31, using miRNA array. Kruppel (or Krüppel)-like factor 4 (Klf4) is a transcription factor and putative tumor suppressor. Both were found to be significantly downregulated in liver cancer tissues and cells. However, little is known about the correlation between Klf4 and miRNA-31 in hepatocellular carcinoma (HCC). The mRNA expression of Klf4 was decreased and inversely associated with the clinical stage, T classification and hepatitis B in patients with HCC, while the expression of miR-31 was lower (r=0.326, P=0.018). Using cell counting kit 8 (CCK8) and Transwell migration assays, we found that Klf4 and miR-31 inhibited the proliferation and metastasis of liver cancer cells. Moreover, we demonstrated that Klf4 directly binds to the promoter of miR-31 and activates its transcription. In vitro experiments confirmed that Klf4 regulated miR-31 and thereby inhibited HCC cell growth and metastasis. Taken together, our findings indicate that Klf4 directly regulates miR-31 in HCC. Thus, miR-31 may serve as a potential diagnostic marker and therapeutic target in HCC.