Loss of SNAIL regulated miR-128-2 on chromosome 3p22.3 targets multiple stem cell factors to promote transformation of mammary epithelial cells

Empagliflozin drives ferroptosis in anoikis-resistant cells by activating miR-128-3p dependent pathway and inhibiting CD98hc in breast cancer

A tumour suppressor miRNA, miR-128-3p, is widely involved in various biological processes and has been found to get downregulated in breast cancer patients. We previously published that ectopically expressed miR-128-3p suppressed migration, invasion, cell cycle arrest, and breast cancer stem cells. In the present study, we explored the role of Empagliflozin (EMPA) as a miR-128-3p functionality-mimicking drug in inducing ferroptosis by inhibiting CD98hc. Given that CD98hc is one of the proteins critical in triggering ferroptosis, we confirmed that miR-128-3p and EMPA inhibited SP1, leading to inhibition of CD98hc expression. Further, transfection with siCD98hc, miR-128-3p mimics, and inhibitors was performed to assess their involvement in the ferroptosis of anoikis-resistant cells. We proved that anoikis-resistant cells possess high ROS and iron levels. Further, miR-128-3p and EMPA treatments induced ferroptosis by inhibiting GSH and enzymatic activity of GPX4 and also induced lipid peroxidation. Moreover, EMPA suppressed bioluminescence of 4T1-Red-FLuc induced thoracic cavity, peritoneal tumour burden and lung nodules in an in-vivo metastatic model of breast cancer. Collectively, we revealed that EMPA sensitized the ECM detached cells to ferroptosis by synergically activating miR-128-3p and lowering the levels of SP1 and CD98hc, making it a potential adjunct drug for breast cancer chemotherapy.

MicroRNA in cardiometabolic health and disease: The perspectives of sex, gender and personalised medicine

BACKGROUND

Personalized medicine represents a novel and integrative approach that focuses on an individual's genetics and epigenetics, precision medicine, lifestyle and exposures as key players of health status and disease phenotypes.

METHODS

In this narrative review, we aim to carefully discuss the current knowledge on gender disparities in cardiometabolic diseases, and we consider the sex- specific expression of miRNAs and their role as promising tool in precision medicine.

RESULTS

Personalised medicine overcomes the restricted care of patient based on a binomial sex approach, by enriching itself with a holistic and dynamic gender integration. Recognized as a major worldwide health emergency, cardiometabolic disorders continue to rise, impacting on health systems and requiring more effective and targeted strategies. Several sex and gender drivers might affect the onset and progression of cardiometabolic disorders in males and females at multiple levels. In this respect, distinct contribution of genetic and epigenetic mechanisms, molecular and physiological pathways, sex hormones, visceral fat and subcutaneous fat and lifestyle lead to differences in disease burden and outcomes in males and females.

CONCLUSIONS

Sex and gender play a pivotal role in precision medicine because the influence the physiology of each individual and the way they interact with environment from intrauterine life.

Unraveling the Potential of miRNAs from CSCs as an Emerging Clinical Tool for Breast Cancer Diagnosis and Prognosis

Breast cancer (BC) is the most diagnosed cancer in women and the second most common cancer globally. Significant advances in BC research have led to improved early detection and effective therapies. One of the key challenges in BC is the presence of BC stem cells (BCSCs). This small subpopulation within the tumor possesses unique characteristics, including tumor-initiating capabilities, contributes to treatment resistance, and plays a role in cancer recurrence and metastasis. In recent years, microRNAs (miRNAs) have emerged as potential regulators of BCSCs, which can modulate gene expression and influence cellular processes like BCSCs' self-renewal, differentiation, and tumor-promoting pathways. Understanding the miRNA signatures of BCSCs holds great promise for improving BC diagnosis and prognosis. By targeting BCSCs and their associated miRNAs, researchers aim to develop more effective and personalized treatment strategies that may offer better outcomes for BC patients, minimizing tumor recurrence and metastasis. In conclusion, the investigation of miRNAs as regulators of BCSCs opens new directions for advancing BC research through the use of bioinformatics and the development of innovative therapeutic approaches. This review summarizes the most recent and innovative studies and clinical trials on the role of BCSCs miRNAs as potential tools for early diagnosis, prognosis, and resistance.

Empagliflozin mediated miR-128-3p upregulation promotes differentiation of hypoxic cancer stem-like cells in breast cancer

AIMS

The hsa-miR-128-3p expression is downregulated in advanced breast cancer patients. Empagliflozin (EMPA) is an anti-diabetic drug with anticancer potential. The present study investigated the effect of EMPA on cancer cell differentiation by acting as a miR-128-3p mimicking drug in breast cancer.

MAIN METHODS

Our results first demonstrate SP1 and PKM2 as the downstream effectors of hsa-miR-128-3p. Further, transfection with siPKM2, miR-128-3p mimics, and inhibitors was performed to assess their involvement in cancer stemness using flow cytometry. Further, EMPA as miR-128-3p mimicking drug was screened and explored on cancer cell differentiation. Then, we treated the 4T1-Red-FLuc allograft breast tumor with EMPA to assess its inhibitory potential toward tumor growth using IVIS® Spectrum. Immunohistochemistry was performed to evaluate cancer cell differentiation and cell proliferation.

KEY FINDINGS

We found that hsa-miR-128-3p is the upstream regulator of SP1 and PKM2 in hypoxic breast cancer cells. Overexpression of miR-128-3p with mimics downregulate SP1 and PKM2, whereas miR-128-3p inhibitor shows an opposite effect. The enhanced expression of miR-128-3p and PKM2 knockdown diminishes hypoxia-induced CD44 expression and enhance CD44⁺/CD24⁺ differentiated cells. We also identified EMPA as the miR-128-3p mimicking drug that can enhance the differentiated cell population. Further, EMPA suppressed in vivo tumor growth, lung metastasis, tumor bioluminescence, and cell proliferation. Therefore, EMPA abrogates breast cancer stemness by inactivating SP1 and PKM2 via enhanced miR-128-3p expression.

SIGNIFICANCE

EMPA could be a promising drug in combination with other chemotherapeutic drugs in advanced breast cancer.

Paracrine secretion of IL8 by breast cancer stem cells promotes therapeutic resistance and metastasis of the bulk tumor cells

BACKGROUND

Breast tumors consist of heterogeneous cellular subpopulations that differ in molecular properties and functional attributes. Cancer stem cells (CSCs) play pivotal roles in cancer therapeutic failure and metastasis. However, it remains indeterminate how CSCs determine the progression of the bulk cancer cell population.

METHODS

Co-culture systems in vitro and co-implantation systems in vivo were designed to characterize the interactions between breast cancer stem cells (BCSCs) and bulk cancer cells. RNA sequencing was performed to study the functional and mechanistic implications of the BCSC secretome on bulk cancer cells. A cytokine antibody array was employed to screen the differentially secreted cytokines in the BCSC secretome. Tail vein injection metastatic models and orthotopic xenograft models were applied to study the therapeutic potential of targeting IL8.

RESULTS

We identified that the BCSC secretome potentiated estrogen receptor (ER) activity in the bulk cancer cell population. The BCSC secretome rendered the bulk cancer cell population resistant to anti-estrogen and CDK4/6 inhibitor therapy; as well as increased the metastatic burden attributable to bulk cancer cells. Screening of the BCSC secretome identified IL8 as a pivotal factor that potentiated ERα activity, endowed tamoxifen resistance and enhanced metastatic burden by regulation of bulk cancer cell behavior. Pharmacological inhibition of IL8 increased the efficacy of fulvestrant and/or palbociclib by reversing tamoxifen resistance and abrogated metastatic burden.

CONCLUSION

Taken together, this study delineates the mechanism by which BCSCs determine the therapeutic response and metastasis of bulk cancer cells; and thereby suggests potential therapeutic strategies to ameliorate breast cancer outcomes. Video Abstract.

Overview of the role and action mechanism of microRNA-128 in viral infections

Recently in vivo and in vitro studies have provided evidence establishing the significance of microRNAs (miRNAs) in both physiological and pathological conditions. In this regard, the role of miRNA-128 (miR-128) in health and diseases has been found, and its critical regulatory role in the context of some viral diseases has been recently identified. For instance, it has been found that miR-128 can serve as an antiviral mediator and significantly limit the replication and dissemination of human immunodeficiency virus type 1 (HIV-1). Besides, it has been noted that poliovirus receptor-related 4 (PVRL4) is post-transcriptionally regulated by miR-128, representing possible miRNA targets that can modulate measles virus infection. Of note, the downregulation of seminal exosomes eca-miR-128 is associated with the long-term persistence of Equine arteritis virus (EAV) in the reproductive tract, and this particular miRNA is a putative regulator of chemokine ligand 16 (C-X-C motif) as determined by target prediction analysis. In this review, the latest information on the role and action mechanism of miR-128 in viral infections will be summarized and discussed in detail.

primiReference: a reference for analysis of primary-microRNA expression in single-nucleus sequencing data

Single-nucleus RNA-sequencing technology has revolutionized understanding of nuanced changes in gene expression between cell types within tissues. Unfortunately, our understanding of regulatory RNAs, such as microRNAs (miRNAs), is limited through both single-cell and single-nucleus techniques due to the short length of miRNAs in the cytoplasm and the incomplete reference of longer primary miRNA (pri-miRNA) transcripts in the nucleus. We build a custom reference to align and count pri-miRNA sequences in single-nucleus data. Using young and aged subventricular zone (SVZ) nuclei, we show differential expression of pri-miRNAs targeting genes involved in neural stem cells (NSC) differentiation in the aged SVZ. Furthermore, using wild-type and 5XFAD mouse model cortex nuclei, to validate the use of primiReference, we find cell-type-specific expression of pri-miRNAs known to be involved in Alzheimer's disease (AD). pri-miRNAs likely contribute to NSC dysregulation with age and AD pathology. primiReference is paramount in capturing a global profile of gene expression and regulation in single-nucleus data and can provide key insights into cell-type-specific expression of pri-miRNAs, paving the way for future studies of regulation and pathway dysregulation. By looking at pri-miRNA abundance and transcriptional differences, regulation of gene expression by miRNAs in disease and aging can be further explored.

Targeting specificity protein 1 with miR-128-3p overcomes TGF-β1 mediated epithelial-mesenchymal transition in breast cancer: An in vitro study

BACKGROUND

Specificity protein 1 (SP1) was found to play a critical role in the regulation of TGF-β1 driven epithelial-mesenchymal transition (EMT). Recent clinical findings demonstrated a significant drop in the expression of miR-128-3p with the cancer progression in breast cancer patients. However, the impact of miR-128-3p on the SP1 expression in breast cancer remains unknown. Herein, we evaluated the role of miR-128-3p mimics in suppressing EMT of breast cancer cell lines by regulating the TGF-β1/SP1 axis.

METHODS

miR-128-3p interaction with SP1 was detected by in silico tools and dual-luciferase reporter assay. qPCR, western blot, and immunocytochemistry experiments were conducted for determining the expression levels of miR-128-3p and EMT markers with and without the treatment of miR-128-3p mimics. Further, to understand the effect of miR-128-3p mimics on cancer progression, experiments such as wound healing assay, transwell assay, adhesion assay, and cell cycle analysis were performed.

RESULTS

A significant inverse relation between SP1 and miR-128-3p levels was found in MCF-7 and MDA-MB-231 cell lines. miR-128-3p overexpression impeded the SP1 mediated EMT markers in TGF-β1 stimulated cells by inhibiting the SP1 nuclear function. Further, treatment with miR-128-3p mimics significantly reduced the migration, invasion and spreading capability of TGF-β1 stimulated cells. Flow cytometry results showed the impeding role of miR-128-3p on the cell cycle progression.

CONCLUSIONS

Upregulated miR-128-3p inhibited SP1, thereby limiting the TGF-β1 induced EMT in MCF-7 and MDA-MB-231 cell lines for the first time. This study may pave the path to explore novel miRNA therapeutics for eradicating advanced breast cancer cases.

The role of epigenetic modifications in drug resistance and treatment of breast cancer

Background

Breast cancer is defined as a biological and molecular heterogeneous disorder that originates from breast cells. Genetic predisposition is the most important factor giving rise to this malignancy. The most notable mutations in breast cancer occur in the BRCA1 and BRCA2 genes. Owing to disease heterogeneity, lack of therapeutic target, anti-cancer drug resistance, residual disease, and recurrence, researchers are faced with challenges in developing strategies to treat patients with breast cancer.

Results

It has recently been reported that epigenetic processes such as DNA methylation and histone modification, as well as microRNAs (miRNAs), have potently contributed to the pathophysiology, diagnosis, and treatment of breast cancer. These observations have persuaded researchers to move their therapeutic approaches beyond the genetic framework toward the epigenetic concept.

Conclusion

Herein we discuss the molecular and epigenetic mechanisms underlying breast cancer progression and resistance as well as various aspects of epigenetic-based therapies as monotherapy and combined with immunotherapy.

microRNAs in cancer chemoresistance: The sword and the shield

Cancer is a multifactorial disease and one of the leading causes of mortality worldwide. Cancer cells develop multiple strategies to reduce drug sensitivity and eventually lead to chemoresistance. Chemoresistance is initiated either by intrinsic factors or due to the prolonged use of chemotherapeutics as acquired resistance. Further, chemoresistance is also one of the major reasons behind tumor recurrence and metastasis. Therefore, overcoming chemoresistance is one of the primary challenges in cancer therapy. Several mechanisms are involved in chemoresistance. Among them, the key role of ABC transporters and tumor microenvironment have been well studied. Recently, microRNAs (miRNAs) regulation in tumor development, metastasis, and chemotherapy has got wider interest due to its role in regulating genes involved in cancer progression and therapy. Noncoding RNAs, including miRNAs, have been associated with the regulation of tumor-suppressor and tumor-promoter genes. Further, miRNA can also be used as a reliable diagnostic and prognostic marker to predict the stage and types of cancer. Recent evidences have revealed that miRNAs regulation also influences the function of drug transporters and the tumor microenvironment, which affects chemosensitivity to cancer cells. Therefore, miRNAs can be a promising target to reverse back chemosensitivity in cancer cells. This review comprehensively discusses the mechanisms involved in cancer chemoresistance and its regulation by miRNAs.

Mechanism of ARPP21 antagonistic intron miR-128 on neurological function repair after stroke

OBJECTIVE

Stroke is a cerebrovascular disorder that often causes neurological function defects. ARPP21 is a conserved host gene of miR-128 controlling neurodevelopmental functions. This study investigated the mechanism of ARPP21 antagonistic intron miR-128 on neurological function repair after stroke.

METHODS

Expressions of ARPP21 and miR-128 in stroke patients were detected. The mouse neurons and astrocytes were cultured in vitro and treated with oxygen-glucose deprivation (OGD). The OGD-treated cells were transfected with pc-ARPP21 and miR-128 mimic. The proliferation of astrocytes, and the apoptosis of neurons and astrocytes were detected, and inflammatory factors of astrocytes were measured. The binding relationship between miR-128 and CREB1 was verified. The rat model of middle cerebral artery occlusion (MCAO) was established. ARPP21 expression in model rats was detected. The effects of pc-ARPP21 on neuron injury, brain edema volume, and cerebral infarct in rats were observed.

RESULTS

ARPP21 expression was downregulated and miR-128 expression was upregulated in stroke patients. pc-ARPP21 facilitated the proliferation of astrocytes and inhibited apoptosis of neurons and astrocytes, and reduced inflammation of astrocytes. miR-128 mimic could reverse these effects of pc-ARPP21 on neurons and astrocytes. miR-128 targeted CREB1 and reduced BDNF secretion. In vitro experiments confirmed that ARPP21 expression was decreased in MCAO rats, and pc-ARPP21 promoted neurological function repair after stroke.

CONCLUSION

ARPP21 upregulated CREB1 and BDNF expressions by antagonizing miR-128, thus inhibiting neuronal apoptosis and promoting neurological function repair after stroke. This study may offer a novel target for the management of stroke.

MicroRNAs and Long Noncoding RNAs as Novel Therapeutic Targets in Estrogen Receptor-Positive Breast and Ovarian Cancers

Aromatase inhibitors (AIs) such as anastrozole, letrozole, and exemestane have shown to prevent metastasis and angiogenesis in estrogen receptor (ER)-positive breast and ovarian tumors. They function primarily by reducing estrogen production in ER-positive post-menopausal breast and ovarian cancer patients. Unfortunately, current AI-based therapies often have detrimental side-effects, along with acquired resistance, with increased cancer recurrence. Thus, there is an urgent need to identify novel AIs with fewer side effects and improved therapeutic efficacies. In this regard, we and others have recently suggested noncoding RNAs (ncRNAs), specifically microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), as potential molecular targets for utilization in modulating cancer hallmarks and overcoming drug resistance in several cancers, including ER-positive breast and ovarian cancer. Herein, we describe the disruptive functions of several miRNAs and lncRNAs seen in dysregulated cancer metabolism, with a focus on the gene encoding for aromatase (CYP19A1 gene) and estrogen synthesis as a novel therapeutic approach for treating ER-positive breast and ovarian cancers. Furthermore, we discuss the oncogenic and tumor-suppressive roles of several miRNAs (oncogenic miRNAs: MIR125b, MIR155, MIR221/222, MIR128, MIR2052HG, and MIR224; tumor-suppressive miRNAs: Lethal-7f, MIR27B, MIR378, and MIR98) and an oncogenic lncRNA (MIR2052HG) in aromatase-dependent cancers via transcriptional regulation of the CYP19A1 gene. Additionally, we discuss the potential effects of dysregulated miRNAs and lncRNAs on the regulation of critical oncogenic molecules, such as signal transducer, and activator of transcription 3, β-catenin, and integrins. The overall goal of this review is to stimulate further research in this area and to facilitate the development of ncRNA-based approaches for more efficacious treatments of ER-positive breast and ovarian cancer patients, with a slight emphasis on associated treatment–delivery mechanisms.

MicroRNA Regulation of Breast Cancer Stemness

Recent advances in our understanding of breast cancer have demonstrated that cancer stem-like cells (CSCs, also known as tumor-initiating cell (TICs)) are central for progression and recurrence. CSCs are a small subpopulation of cells present in breast tumors that contribute to growth, metastasis, therapy resistance, and recurrence, leading to poor clinical outcome. Data have shown that cancer cells can gain characteristics of CSCs, or stemness, through alterations in key signaling pathways. The dysregulation of miRNA expression and signaling have been well-documented in cancer, and recent studies have shown that miRNAs are associated with breast cancer initiation, progression, and recurrence through regulating CSC characteristics. More specifically, miRNAs directly target central signaling nodes within pathways that can drive the formation, maintenance, and even inhibition of the CSC population. This review aims to summarize these research findings specifically in the context of breast cancer. This review also discusses miRNAs as biomarkers and promising clinical therapeutics, and presents a comprehensive summary of currently validated targets involved in CSC-specific signaling pathways in breast cancer.

Targeting the Sonic Hedgehog Pathway to Suppress the Expression of the Cancer Stem Cell (CSC)-Related Transcription Factors and CSC-Driven Thyroid Tumor Growth

Simple Summary

Poorly differentiated and anaplastic thyroid cancers respond poorly to surgery, radiation, and hormone therapy. Cancer stem cells play an important role in tumor growth, drug resistance, and recurrence. This study focuses on how the sonic hedgehog (Shh) pathway maintains thyroid cancer stem cell self-renewal and whether it can be targeted for anticancer therapy. The authors report that the Shh pathway regulates the expression of BMI1 and SOX2, two genes involved in stem cell self-renewal, and that targeting the Shh pathway has little effect on thyroid tumor xenografts but can inhibit the growth of tumor xenografts derived from thyroid cancer stem cells. This study advances the knowledge on how thyroid cancer stem cells regenerate and highlights the potential therapeutic values of targeting the Shh pathway.

Abstract

The sonic hedgehog (Shh) pathway plays important roles in tumorigenesis, tumor growth, drug resistance, and metastasis. We and others have reported earlier that this pathway is highly activated in thyroid cancer. However, its role in thyroid cancer stem cell (CSC) self-renewal and tumor development remains incompletely understood. B lymphoma Mo-MLV insertion region 1 homolog (BMI1) and SRY-Box Transcription Factor 2 (SOX2) are two CSC-related transcription factors that have been implicated in promoting CSC self-renewal. The objective of our current investigation was to determine the role of the Shh pathway in regulating BMI1 and SOX2 expression in thyroid cancer and promoting thyroid tumor growth and development. Here we report that inhibition of the Shh pathway by Gli1 siRNA or by cyclopamine and GANT61 reduced BMI1 and SOX2 expression in SW1736 and KAT-18 cells, two anaplastic thyroid cancer cell lines. The opposite results were obtained in cells overexpressing Gli1 or its downstream transcription factor Snail. The Shh pathway regulated SOX2 and BMI1 expression at a transcriptional and post-transcriptional level, respectively. GANT61 treatment suppressed the growth of SW1736 CSC-derived tumor xenografts but did not significantly inhibit the growth of tumors grown from bulk tumor cells. Clinicopathological analyses of thyroid tumor specimens by immunohistochemical (IHC) staining revealed that BMI1 and SOX2 were highly expressed in thyroid cancer and correlated with Gli1 expression. Our study provides evidence that activation of the Shh pathway leads to increased BMI1 and SOX2 expression in thyroid cancer and promotes thyroid CSC-driven tumor initiation. Targeting the Shh pathway may have therapeutic value for treating thyroid cancer and preventing recurrence.

A hybrid systems biology and systems pharmacology investigation of Zingerone's effects on reconstructed human epidermal tissues

Background

As individuals live longer, elderly populations can be expected to face issues. This pattern urges researchers to investigate the aging concept further to produce successful anti-aging agents. In the current study, the effects of Zingerone (a natural compound) on epidermal tissues were analyzed using a bioinformatics approach.

Methods

For this purpose, we chose the GEO dataset GSE133338 to carry out the systems biology and systems pharmacology approaches, ranging from identifying the differentially expressed genes to analyzing the gene ontology, determining similar structures of Zingerone and their features (i.e., anti-oxidant, anti-inflammatory, and skin disorders), constructing the gene-chemicals network, analyzing gene-disease relationships, and validating significant genes through the evidence presented in the literature.

Results

The post-processing of the microarray dataset identified thirteen essential genes among control and Zingerone-treated samples. The procedure revealed various structurally similar chemical and herbal compounds with possible skin-related effects. Additionally, we studied the relationships of differentially expressed genes with skin-related diseases and validated their direct connections with skin disorders the evidence available in the literature. Also, the analysis of the microarray profiling dataset revealed the critical role of interleukins as a part of the cytokines family on skin aging progress.

Conclusions

Zingerone, and potentially any constituents of Zingerone (e.g., their similar compound scan functionality), can be used as therapeutic agents in managing skin disorders such as skin aging. However, the beneficial effects of Zingerone should be assessed in other models (i.e., human or animal) in future studies.

Connecting the Missing Dots: ncRNAs as Critical Regulators of Therapeutic Susceptibility in Breast Cancer

Whether acquired or de novo, drug resistance remains a significant hurdle in achieving therapeutic success in breast cancer (BC). Thus, there is an urge to find reliable biomarkers that will help in predicting the therapeutic response. Stable and easily accessible molecules such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are regarded as valuable prognostic biomarkers and therapeutic targets since they act as crucial regulators of the various mechanisms involved in BC drug resistance. Here, we reviewed the current literature on ncRNAs as mediators of resistance to systemic therapies in BC. Interestingly, upon integrating data results from individual studies, we concluded that miR-221, miR-222, miR-451, Urothelial Carcinoma Associated 1 (UCA1), and Growth arrest-specific 5 (GAS5) are strong candidates as prognostic biomarkers and therapeutic targets since they are regulating multiple drug resistance phenotypes in BC. However, further research around their clinical implications is needed to validate and integrate them into therapeutic applications. Therefore, we believe that our review may provide relevant evidence for the selection of novel therapeutic targets and prognostic biomarkers for BC and will serve as a foundation for future translational research in the field.

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.

The regulatory mechanism and biological significance of the Snail-miR590-VEGFR-NRP1 axis in the angiogenesis, growth and metastasis of gastric cancer

Vascular endothelial growth factor receptor (VEGFR) and neuropilins (NRPs), a co-receptor of VEGF, play a key role in the formation and development of blood vessels and in tumour growth and metastasis. However, whether VEGFR1/2 and NRP1 are regulated by the same upstream mechanism is unclear, especially in gastric cancer. We used prediction tools to detect miRNAs that may simultaneously regulate VEGFR1/2 and NRP1, and we finally determined that miR-590 can simultaneously regulate VEGFR1/2 and NRP1 in gastric cancer. We discovered that miR-590 was downregulated in gastric cancer tissues and cell lines, and this was related to the dysregulation of the transcription factor SNAIL. In addition, the overexpression of miR-590 inhibits the migration, invasion, proliferation and D-MVA levels of gastric cancer cells in vivo and in vitro by targeting VEGFR1/2 and NRP1. We also demonstrated that miR-590 may be a useful marker for the prognosis of gastric cancer with Kaplan–Meier survival analysis. Since the epithelial-to-mesenchymal transition (EMT) is an important mechanism of tumour invasion and metastasis and VEGFR1/2 and NRP1 can promote the occurrence of EMT, we speculated that miR-590 can regulate the occurrence of EMT. Immunoblot and immunofluorescence analyses confirmed that the overexpression of miR-590 can inhibit the EMT in gastric cancer cells. Since SNAIL is also a mesenchymal marker, our results revealed a new, positive feedback loop. As a transcription factor, SNAIL inhibits the expression of miR-590, thereby upregulating the expression levels of NRP1 and VEGFR1/2; this leads to the development of EMT in gastric cancer and the upregulation of SNAIL.

Expression and prognostic value of mRNAs in lower grade glioma with MGMT promoter methylated

Due to the varied overall survival (OS), limited studies focus on the factors that affect the prognosis for lower grade glioma patients (LGGs) with MGMT promoter methylated. A total of 579 samples (TCGA LGGs 456; CGGA LGGs 123) were included to identify potential genes for LGGs with MGMT promoter methylated. All bioinformatics analyses were conducted using SPSS software and GraphPad Prism 6. Based on COX regression analysis, we established a four-gene signature (ALDOC, APOBEC3C, ANXA1 and ARPP21) and divided LGGs into two groups based on median risk score. The OS of LGGs in high risk group was shorter than low risk group (P < 0.0001). Furthermore, the OS in high risk group were shorter than low risk group in Grade II and III, respectively (P = 0.0003; P = 0.0104). It showed that the signature was an independent prognosis factor on multivariate Cox regression analysis (P = 0.033). Patients in high group tended to displayed high grade (GIII), IDH1 wild type and mesenchymal subtype preference. Four-gene signature was discovered for LGGs with MGMT promoter methylated. Our findings suggested that the four genes could serve as prognostic biomarkers.

miR-128-3p Is a Novel Regulator of Vascular Smooth Muscle Cell Phenotypic Switch and Vascular Diseases

RATIONALE

MicroRNAs (miRNAs, miRs) are small noncoding RNAs that modulate gene expression by negatively regulating translation of target genes. Although the role of several miRNAs in vascular smooth muscle cells (VSMCs) has been extensively characterized, the function of miRNA-128-3p (miR-128) is still unknown.

OBJECTIVE

To determine if miR-128 modulates VSMC phenotype and to define the underlying mechanisms.

METHODS AND RESULTS

We screened for miRNAs whose expression is modulated by an altered DNA methylation status in VSMCs, and among the hits, we selected miR-128. We found that miR-128 was expressed in various tissues, primary murine cells, and pathological murine and human vascular specimens. Through gain- and loss-of-function approaches, we determined that miR-128 affects VSMC proliferation, migration, differentiation, and contractility. The alterations of those properties were dependent upon epigenetic regulation of key VSMC differentiation genes; notably, Kruppel-like factor 4 was found to be a direct target of miR-128 and able to modulate the methylation status of the pivotal VSMC gene myosin heavy chain 11 (Myh11). Finally, in vivo lentiviral delivery of miR-128 prevented intimal hyperplasia in a mouse model of carotid restenosis without modifying vital cardiovascular parameters.

CONCLUSION

miR-128 is a critical modulator of VSMCs and is regulated by epigenetic modifications upon stress. Its modulation in the context of disease could be exploited for therapeutic purposes.

Amygdala-Based Altered miRNome and Epigenetic Contribution of miR-128-3p in Conferring Susceptibility to Depression-Like Behavior via Wnt Signaling

BACKGROUND

Recent studies suggest that microRNAs (miRNAs) can participate in depression pathogenesis by altering a host of genes that are critical in corticolimbic functioning. The present study focuses on examining whether alterations in the miRNA network in the amygdala are associated with susceptibility or resiliency to develop depression-like behavior in rats.

METHODS

Amygdala-specific altered miRNA transcriptomics were determined in a rat depression model following next-generation sequencing method. Target prediction analyses (cis- and trans) and qPCR-based assays were performed to decipher the functional role of altered miRNAs. miRNA-specific target interaction was determined using in vitro transfection assay in neuroblastoma cell line. miRNA-specific findings from the rat in vivo model were further replicated in postmortem amygdala of major depressive disorder (MDD) subjects.

RESULTS

Changes in miRNome identified 17 significantly upregulated and 8 significantly downregulated miRNAs in amygdala of learned helpless (LH) compared with nonlearned helpless rats. Prediction analysis showed that the majority of the upregulated miRNAs had target genes enriched for the Wnt signaling pathway. Among altered miRNAs, upregulated miR-128-3p was identified as a top hit based on statistical significance and magnitude of change in LH rats. Target validation showed significant downregulation of Wnt signaling genes in amygdala of LH rats. A discernable increase in expression of amygdalar miR-128-3p along with significant downregulation of key target genes from Wnt signaling (WNT5B, DVL, and LEF1) was noted in MDD subjects. Overexpression of miR-128-3p in a cellular model lead to a marked decrease in the expression of Dvl1 and Lef1 genes, confirming them as validated targets of miR-128-3p. Additional evidence suggested that the amygdala-specific diminished expression of transcriptional repressor Snai1 could be potentially linked to induced miR-128-2 expression in LH rats. Furthermore, an amygdala-specific posttranscriptional switching mechanism could be active between miR-128-3p and RNA binding protein Arpp21 to gain control over their target genes such as Lef1.

CONCLUSION

Our study suggests that in amygdala a specific set of miRNAs may play an important role in depression susceptibility, which could potentially be mediated through Wnt signaling.

Interplay among SNAIL Transcription Factor, MicroRNAs, Long Non-Coding RNAs, and Circular RNAs in the Regulation of Tumor Growth and Metastasis

SNAIL (SNAI1) is a zinc finger transcription factor that binds to E-box sequences and regulates the expression of genes. It usually acts as a gene repressor, but it may also activate the expression of genes. SNAIL plays a key role in the regulation of epithelial to mesenchymal transition, which is the main mechanism responsible for the progression and metastasis of epithelial tumors. Nevertheless, it also regulates different processes that are responsible for tumor growth, such as the activity of cancer stem cells, the control of cell metabolism, and the regulation of differentiation. Different proteins and microRNAs may regulate the SNAIL level, and SNAIL may be an important regulator of microRNA expression as well. The interplay among SNAIL, microRNAs, long non-coding RNAs, and circular RNAs is a key event in the regulation of tumor growth and metastasis. This review for the first time discusses different types of regulation between SNAIL and non-coding RNAs with a focus on feedback loops and the role of competitive RNA. Understanding these mechanisms may help develop novel therapeutic strategies against cancer based on microRNAs.

Prediction of clusters of miRNA binding sites in mRNA candidate genes of breast cancer subtypes

The development of breast cancer (BC) subtypes is controlled by distinct sets of candidate genes, and the expression of these genes is regulated by the binding of their mRNAs with miRNAs. Predicting miRNA associations and target genes is thus essential when studying breast cancer. The MirTarget program identifies the initiation of miRNA binding to mRNA, the localization of miRNA binding sites in mRNA regions, and the free energy from the binding of all miRNA nucleotides with mRNA. Candidate gene mRNAs have clusters (miRNA binding sites with overlapping nucleotide sequences). mRNAs of EPOR, MAZ and NISCH candidate genes of the HER2 subtype have clusters, and there are four clusters in mRNAs of MAZ, BRCA2 and CDK6 genes. Candidate genes of the triple-negative subtype are targets for multiple miRNAs. There are 11 sites in CBL mRNA, five sites in MMP2 mRNA, and RAB5A mRNA contains two clusters in each of the three sites. In SFN mRNA, there are two clusters in three sites, and one cluster in 21 sites. Candidate genes of luminal A and B subtypes are targets for miRNAs: there are 21 sites in FOXA1 mRNA and 15 sites in HMGA2 mRNA. There are clusters of five sites in mRNAs of ITGB1 and SOX4 genes. Clusters of eight sites and 10 sites are identified in mRNAs of SMAD3 and TGFB1 genes, respectively. Organizing miRNA binding sites into clusters reduces the proportion of nucleotide binding sites in mRNAs. This overlapping of miRNA binding sites creates a competition among miRNAs for a binding site. From 6,272 miRNAs studied, only 29 miRNAs from miRBase and 88 novel miRNAs had binding sites in clusters of target gene mRNA in breast cancer. We propose using associations of miRNAs and their target genes as markers in breast cancer subtype diagnosis.

Long noncoding RNA Linc00460 promotes breast cancer progression by regulating the miR-489-5p/FGF7/AKT axis

Purpose: Evidence indicates that long noncoding RNAs (lncRNA) possess important roles in various cellular processes and that dysregulation of lncRNAs promotes tumor progression. However, the expression patterns and biological functions of many specific lncRNAs in breast cancer remain to be determined. Methods: Quantitative real-time polymerase chain reaction was performed to detect Linc00460, miR-489-5p and FGF7 expression. Protein levels were determined using Western blot. MTT and colony formation assay were used to measure cell proliferation. Transwell assays were conducted to determine cell migration and invasion. Luciferase reporter assays were carried out to assess the interaction between miR-489-5p and Linc00460 or FGF7. Biotin pull-down assay was used to detect the direct interaction between miR-489-5p and Linc00460. In vivo experiments were performed to measure tumor formation and lung metastasis. Results: We demonstrated that lncRNA Linc00460 was upregulated in breast cancer, and its expression level was positively associated with lymphatic metastasis and poor overall survival. Forced expression of Linc00460 increased, whereas Linc00460 silencing decreased, breast cancer cell viability, migration and invasion both in vitro and in vivo. Linc00460 was identified as a direct target of miR-489-5p, which further targeted FGF7 and exerted oncogenic functions in breast cancer. Mechanistically, Linc00460 served as a competing endogenous RNA of FGF-7 mRNA by sponging miR-489-5p, resulting in upregulated FGF7 expression and AKT activity. Notably, forced expression of miR-489-5p abrogated Linc00460-mediated oncogenic behavior and activation of the FGF7-AKT pathway in breast cancer cells. Conclusion: We have demonstrated that Linc00460 promotes breast cancer progression partly through the miR-489-5p/FGF7/AKT axis.

Amplification of hsa-miR-191/425 locus promotes breast cancer proliferation and metastasis by targeting DICER1

The dysregulation of micro RNAs (miRNAs) is a crucial characteristic of human cancers. Herein, we observed frequent amplification of the MIR191/425 locus in breast cancer, which is correlated with poor survival outcome. We demonstrated that the miR-191/425 cluster binds the 3' untranslated region of the DICER1 transcript and posttranscriptionally represses DICER1 expression, thereby impairing global miRNAs biogenesis. Functionally, the forced expression of miR-191 or miR-425 stimulated the proliferation, survival, migration and invasion of breast cancer cells, whereas the inhibition of miR-191 or miR-425 suppressed these oncogenic behaviors of breast cancer cells, in a manner dependent on miR-191/425-mediated downregulation of DICER1. Furthermore, the miR-191/425 cluster promoted breast tumor growth, invasion and metastasis in vivo. The let-7 family of miRNAs was downregulated upon forced expression of miR-191 or miR-425, with a corresponding increase in the levels of let-7 target, high-mobility group AT-hook 2 (HMGA2). The forced expression of let-7 partially abrogated the miR-191/425-mediated oncogenic effects in breast cancer cells, suggestive of let-7 as a downstream effector of the miR-191/425-DICER1 axis. Collectively, we proposed that the inhibition of global miRNA processing, through miR-191/425-mediated downregulation of DICER1, promotes breast cancer progression.

Loss of Estrogen-Regulated MIR135A1 at 3p21.1 Promotes Tamoxifen Resistance in Breast Cancer

The dysregulation of miRNAs has been increasingly recognized as a critical mediator of cancer development and progression. Here, we show that frequent deletion of the MIR135A1 locus is associated with poor prognosis in primary breast cancer. Forced expression of miR-135a decreased breast cancer progression, while inhibition of miR-135a with a specific miRNA sponge elicited opposing effects, suggestive of a tumor suppressive role of miR-135a in breast cancer. Estrogen receptor alpha (ERα) bound the promoter of MIR135A1 for its transcriptional activation, whereas tamoxifen treatment inhibited expression of miR-135a in ERα+ breast cancer cells. miR-135a directly targeted ESR1, ESRRA, and NCOA1, forming a negative feedback loop to inhibit ERα signaling. This regulatory feedback between miR-135a and ERα demonstrated that miR-135a regulated the response to tamoxifen. The tamoxifen-mediated decrease in miR-135a expression increased the expression of miR-135a targets to reduce tamoxifen sensitivity. Consistently, miR-135a expression was downregulated in ERα+ breast cancer cells with acquired tamoxifen resistance, while forced expression of miR-135a partially resensitized these cells to tamoxifen. Tamoxifen resistance mediated by the loss of miR-135a was shown to be partially dependent on the activation of the ERK1/2 and AKT pathways by miR-135a-targeted genes. Taken together, these results indicate that deletion of the MIR135A1 locus and decreased miR-135a expression promote ERα+ breast cancer progression and tamoxifen resistance.Significance: Loss of miR-135a in breast cancer disrupts an estrogen receptor-induced negative feedback loop, perpetuating disease progression and resistance to therapy.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/17/4915/F1.large.jpg Cancer Res; 78(17); 4915-28. ©2018 AACR.

TGFβ1 regulates HGF-induced cell migration and hepatocyte growth factor receptor MET expression via C-ets-1 and miR-128-3p in basal-like breast cancer

Breast cancer is the most common cancer in women worldwide. The tumor microenvironment contributes to tumor progression by inducing cell dissemination from the primary tumor and metastasis. TGFβ signaling is involved in breast cancer progression and is specifically elevated during metastatic transformation in aggressive breast cancer. In this study, we performed genomewide correlation analysis of TGFBR2 expression in a panel of 51 breast cancer cell lines and identified that MET is coregulated with TGFBR2. This correlation was confirmed at the protein level in breast cancer cell lines and human tumor tissues. Flow cytometric analysis of luminal and basal‐like breast cancer cell lines and examination of 801 tumor specimens from a prospective cohort of breast cancer patients using reverse phase protein arrays revealed that expression of TGFBR2 and MET is increased in basal‐like breast cancer cell lines, as well as in triple‐negative breast cancer tumor tissues, compared to other subtypes. Using real‐time cell analysis technology, we demonstrated that TGFβ1 triggered hepatocyte growth factor (HGF)‐induced and MET‐dependent migration in vitro. Bioinformatic analysis predicted that TGFβ1 induces expression of C‐ets‐1 as a candidate transcription factor regulating MET expression. Indeed, TGFβ1‐induced expression of ETS1 and breast cancer cell migration was blocked by knockdown of ETS1. Further, we identified that MET is a direct target of miR‐128‐3p and that this miRNA is negatively regulated by TGFβ1. Overexpression of miR‐128‐3p reduced MET expression and abrogated HGF‐induced cell migration of invasive breast cancer cells. In conclusion, we have identified that TGFβ1 regulates HGF‐induced and MET‐mediated cell migration, through positive regulation of C‐ets‐1 and negative regulation of miR‐128‐3p expression in basal‐like breast cancer cell lines and in triple‐negative breast cancer tissue.

Effects of miRNAs on functions of breast cancer stem cells and treatment of breast cancer

Breast cancer is one of the most common malignancies for women, which accounts for 30% of all female malignancies. The formation of breast cancer stem cells (BCSCs) is attributed to the acquisition of stemness of tumor cells. With self-renewal potential, these stem cells are insensitive to either radiotherapy or chemotherapy but are significant in regulating tumor behaviors and drug resistance. MicroRNA (miRNA) is a kind of noncoding small RNA for negatively regulating gene expressions. Research findings suggest that many miRNAs specifically regulate the expression of target genes and signal pathways of BCSCs. They play an important role in self-renewal, growth, and metastasis of breast cancer cells as potential targets for treating breast cancer. These signal pathways include phosphatase and tensin homolog deleted on chromosome 10-phosphatidylinositol 3-kinase/Akt, Wnt/β-catenin, Notch, and so on. This paper reviews the progress of research about miRNAs in self-renewal, metastasis, epithelial-mesenchymal transition and metastasis, mediation of resistance to chemotherapies, and treatment of breast cancer.

The SNAIL/miR-128 axis regulated growth, invasion, metastasis, and epithelial-to-mesenchymal transition of gastric cancer

miR-128 is expressed in various tumors, but its expression and function in gastric cancer have not been defined. Thus, the goal of this study was to characterize miR-128 in gastric cancer. We found first that miR-128 is down-regulated in gastric cancer cell lines and tissues, and this dysregulation is correlated with DNA methylation and the transcription factor SNAIL. Using prediction tools, western blotting, and luciferase reporter assays, we found that Bmi-1 was the direct target of miR-128. Additionally, overexpression of miR-128 inhibited gastric cancer cell migration, invasion, and proliferation by targeting Bmi-1 in vitro and in vivo. We also documented, with receiver operating characteristic curves and Kaplan-Meier survival analysis, that miR-128 and Bmi-1 may be useful markers for diagnosing and estimating the prognosis of gastric cancer patients. As the epithelial-to-mesenchymal transition is an important mechanism associated with cancer invasion and metastasis, we inferred that miR-128 could regulate this mechanism in gastric cancer. In fact, we found that miR-128 could reverse epithelial-to-mesenchymal transition induced by Bmi-1 via the PI3K/AKT pathway. Because SNAIL also acts as a mesenchymal marker, our findings identified a novel positive feedback loop in which the transcription factor SNAIL curbs the expression of miR-128, and then down-regulated miR-128 promotes the expression of Bmi-1; finally, overexpression of Bmi-1 drives the epithelial-to-mesenchymal transition process via the PI3K/AKT pathway, and the expression of SNAIL is up-regulated.

Novel prognostic and predictive microRNA targets for triple-negative breast cancer

Triple-negative breast cancers (TNBCs) account for ∼25% of all invasive carcinomas and represent a large subset of aggressive, high-grade tumors. Despite current research focused on understanding the genetic landscape of TNBCs, reliable prognostic and predictive biomarkers remain limited. Although dysregulated microRNAs (miRNAs) have emerged as key players in many cancer types, the role of miRNAs in TNBC disease progression is unclear. We performed miRNA profiling of 51 TNBCs by next-generation sequencing to reveal differentially expressed miRNAs. A total of 228 miRNAs were identified. Three miRNAs (miR-224-5p, miR-375, and miR-205-5p) separated the tumors based on basal status. Six miRNAs (high let-7d-3p, miR-203b-5p, and miR-324-5p; low miR-30a-3p, miR-30a-5p, and miR-199a-5p) were significantly associated with decreased overall survival (OS) and 5 miRNAs (high let-7d-3p; low miR-30a-3p, miR-30a-5p, miR-30c-5p, and miR-128-3p) with decreased relapse-free survival (RFS). On multivariate analysis, high expression of let-7d-3p and low expression of miR-30a were independent predictors of decreased OS and RFS. High expression of miR-95-3p was significantly associated with decreased OS and RFS in patients treated with anthracycline-based chemotherapy. Five miRNAs (let-7d-3p, miR-30a-3p, miR-30c-5p, miR-128-3p, and miR-95-3p) were validated by quantitative RT-PCR. Our findings unveil novel prognostic and predictive miRNA targets for TNBC, including a miRNA signature that predicts patient response to anthracycline-based chemotherapy. This may improve clinical management and/or lead to the development of novel therapies.-Turashvili, G., Lightbody, E. D., Tyryshkin, K., SenGupta, S. K., Elliott, B. E., Madarnas, Y., Ghaffari, A., Day, A., Nicol, C. J. B. Novel prognostic and predictive microRNA targets for triple-negative breast cancer.

miR128-1 inhibits the growth of glioblastoma multiforme and glioma stem-like cells via targeting BMI1 and E2F3

MicroRNA128-1 (miR128-1), as a brain-specific miRNA, is downregulated in glioblastoma multiforme (GBM) and closely associated with the progression of GBM. However, the underlying molecular mechanism of the downregulation and its role in the regulation of tumorigenesis and anticancer drug resistance in GBM remains largely unknown. In the current study,we found that miR128-1 was downregulated in GBM and glioma stem-like cells (GSCs). Intriguingly, treatment with the DNA methylation inhibitors 5-Aza-CdR (Aza) and 4-phenylbutyric acid (PBA) resulted in miR128-1 upregulation in both GBM cells and GSCs. Either forced expression of miR128-1 or Aza/PBA treatment inhibited tumor cell proliferation, migration and invasion in vitro. Moreover, overexpression of miR128-1 inhibited the growth of transplant tumor in vivo. BMI1 and E2F3 were found to be direct targets of miR128-1 and downregulated by miR128-1 in vitro and in vivo. Our results revealed a mechanism of methylation that controls miR128-1 expression in GBM cells and GSCs and indicate miR128-1 could function as a tumor suppressor in GBM by negatively regulating tumor cell proliferation, invasion and self-renewal through direct targeting BMI1 and E2F3. Our findings suggest that DNA methylation inhibitors are potential agents for GBM treatment by upregulating miR-128-1.

miR-128 Regulates Genes Associated with Inflammation and Fibrosis of Rat Kidney Cells In Vitro

microRNAs (miRNAs) regulate diverse cellular functions and signaling pathways via inhibiting the expression of their target genes. Given that miR-128 mediates mitogen-activated protein kinase signaling and production of reactive oxygen species and pro-inflammatory chemokines in various types of cells and tissues, and that miR-128 is differentially expressed in aged and diseased kidneys, we hypothesized that miR-128 may play key roles in kidney inflammation. Hence, in this study, we evaluated the biological effects of miR-128 in normal rat kidney (NRK) cells in vitro. Our results revealed that overexpression of miR-128 enhanced expression of genes associated with inflammation, pro-inflammatory cytokines and fibrosis in NRK cells. The recent reports showing that expression of miR-128 is increased in liver and lung fibrosis, together with the findings in this study, suggest that miR-128 may be a pro-fibrotic miRNA that regulates fibrosis in various tissues. Anat Rec, 301:913-921, 2018. © 2017 Wiley Periodicals, Inc.

MicroRNA miR-128 represses LINE-1 (L1) retrotransposition by down-regulating the nuclear import factor TNPO1

Repetitive elements, including LINE-1 (L1), comprise approximately half of the human genome. These elements can potentially destabilize the genome by initiating their own replication and reintegration into new sites (retrotransposition). In somatic cells, transcription of L1 elements is repressed by distinct molecular mechanisms, including DNA methylation and histone modifications, to repress transcription. Under conditions of hypomethylation (e.g. in tumor cells), a window of opportunity for L1 derepression arises, and additional restriction mechanisms become crucial. We recently demonstrated that the microRNA miR-128 represses L1 activity by directly binding to L1 ORF2 RNA. In this study, we tested whether miR-128 can also control L1 activity by repressing cellular proteins important for L1 retrotransposition. We found that miR-128 targets the 3' UTR of nuclear import factor transportin 1 (TNPO1) mRNA. Manipulation of miR-128 and TNPO1 levels demonstrated that induction or depletion of TNPO1 affects L1 retrotransposition and nuclear import of an L1-ribonucleoprotein complex (using L1-encoded ORF1p as a proxy for L1-ribonucleoprotein complexes). Moreover, TNPO1 overexpression partially reversed the repressive effect of miR-128 on L1 retrotransposition. Our study represents the first description of a protein factor involved in nuclear import of the L1 element and demonstrates that miR-128 controls L1 activity in somatic cells through two independent mechanisms: direct binding to L1 RNA and regulation of a cellular factor necessary for L1 nuclear import and retrotransposition.

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

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

Knockdown of miR-128a induces Lin28a expression and reverts myeloid differentiation blockage in acute myeloid leukemia

Lin28A is a highly conserved RNA-binding protein that concurs to control the balance between stemness and differentiation in several tissue lineages. Here, we report the role of miR-128a/Lin28A axis in blocking cell differentiation in acute myeloid leukemia (AML), a genetically heterogeneous disease characterized by abnormally controlled proliferation of myeloid progenitor cells accompanied by partial or total inability to undergo terminal differentiation. First, we found Lin28A underexpressed in blast cells from AML patients and AML cell lines as compared with CD34+ normal precursors. In vitro transfection of Lin28A in NPM1-mutated OCI-AML3 cell line significantly triggered cell-cycle arrest and myeloid differentiation, with increased expression of macrophage associate genes (EGR2, ZFP36 and ANXA1). Furthermore, miR-128a, a negative regulator of Lin28A, was found overexpressed in AML cells compared with normal precursors, especially in acute promyelocytic leukemia (APL) and in ‘AML with maturation’ (according to 2016 WHO classification of myeloid neoplasms and acute leukemia). Its forced overexpression by lentiviral infection in OCI-AML3 downregulated Lin28A with ensuing repression of macrophage-oriented differentiation. Finally, knockdown of miR-128a in OCI-AML3 and in APL/AML leukemic cells (by transfection and lentiviral infection, respectively) induced myeloid cell differentiation and increased expression of Lin28A, EGR2, ZFP36 and ANXA1, reverting myeloid differentiation blockage. In conclusion, our findings revealed a new mechanism for AML differentiation blockage, suggesting new strategies for AML therapy based upon miR-128a inhibition.

VEGFA links self-renewal and metastasis by inducing Sox2 to repress miR-452, driving Slug

Cancer stem cells (CSC) appear to have increased metastatic potential, but mechanisms underlying this are poorly defined. Here we show that VEGFA induction of Sox2 promotes EMT and tumor metastasis. In breast lines and primary cancer culture, VEGFA rapidly upregulates SOX2 expression, leading to SNAI2 induction, EMT, increased invasion and metastasis. We show Sox2 downregulates miR-452, which acts as a novel metastasis suppressor to directly target the SNAI2 3′-untranslated region (3′-UTR). VEGFA stimulates Sox2- and Slug-dependent cell invasion. VEGFA increases lung metastasis in vivo, and this is abrogated by miR-452 overexpression. Furthermore, SNAI2 transduction rescues metastasis suppression by miR-452. Thus, in addition to its angiogenic action, VEGFA upregulates Sox2 to drive stem cell expansion, together with miR-452 loss and Slug upregulation, providing a novel mechanism whereby cancer stem cells acquire metastatic potential. Prior work showed EMT transcription factor overexpression upregulates CSC. Present work indicates that stemness and metastasis are a two-way street: Sox2, a major mediator of CSC self-renewal, also governs the metastatic process.

NR2F2 inhibits Smad7 expression and promotes TGF-β-dependent epithelial-mesenchymal transition of CRC via transactivation of miR-21

Metastasis is one of the most decisive factors influencing CRC patient prognosis and current studies suggest that a molecular mechanism known as EMT broadly regulates cancer metastasis. NR2F2 is a key molecule in the development of CRC, but the roles and underlying mechanisms of NR2F2 in TGF-β induced EMT in CRC remain largely unknown. In the current study, we were interested to examine the role of NR2F2 in the TGF-β-induced EMT in CRC. Here, we found NR2F2 was upregulated in CRC cells and promotes TGF-β-induced EMT in CRC. Using comparative miRNA profiling TGF-β pre-treated CRC cells in which NR2F2 had been knocked down with that of control cells, we identified miR-21 as a commonly downregulated miRNA in HT29 cells treated with TGF-β and NR2F2 siRNA, and its downregulation inhibiting migration and invasion of CRC cells. Moreover, we found NR2F2 could transcriptional activated miR-21 expression by binding to miR-21 promoter in HT29 by ChIP and luciferase assay. In the last, our data demonstrated that Smad7 was the direct target of miR-21 in CRC cells. Thus, NR2F2 could promote TGF-β-induced EMT and inhibit Smad7 expression via transactivation of miR-21, and NR2F2 may be a new common therapeutic target for CRC.

MiR-128b is down-regulated in gastric cancer and negatively regulates tumour cell viability by targeting PDK1/Akt/NF-κB axis

Gastric cancer (GC) is the fourth most prevalent type of cancer worldwide, which is usually caused by the interaction between environmental and genetic factors, or epigenetic aspects. Referring to the non-coding RNAs, miR-128b has been reported to be associated with many tumour cases, and exerts distinct functions in different types of cancers. However, the function of miR-128b in GC onset and progression largely remains unknown. In the present study, we found that miR-128b expression was down-regulated in tissues from 18 GC patients and 3 carcinoma cell lines. In turn, over-expression of miR-128b suppressed GC cell proliferation, invasion and promoted apoptosis. Moreover, miR-128b was predicted to bind the 3'UTR of PDK1 gene using bioinformatic target-screening tools. Accordingly, ectopic expression of miR-128b inhibited the PDK1 expression at both transcriptional and post-transcriptional levels, and furthermore, the expression of gene tailed by the 3'UTR of PDK1 gene was significantly decreased in a dualluciferase reporter assay, suggesting that PDK1 was a direct target of miR-128b in GC cells. In the conditon of miR- 128b over-expression, we also observed spontaneous inactivation of the Akt/NF-κB signalling, implying PDK1 was a potential regulator of this pathway. In conclusion, our study shed some novel light on miR-128b-PDK1/Akt/NF-κB axis on GC progression.

The Inhibition of microRNA-128 on IGF-1-Activating mTOR Signaling Involves in Temozolomide-Induced Glioma Cell Apoptotic Death

Temozolomide (TMZ), an alkylating agent of the imidazotetrazine series, is a first-line chemotherapeutic drug used in the clinical therapy of glioblastoma multiforme, the most common and high-grade primary glioma in adults. Micro (mi)RNAs, which are small noncoding RNAs, post-transcriptionally regulate gene expressions and are involved in gliomagenesis. However, no studies have reported relationships between TMZ and miRNA gene regulation. We investigated TMZ-mediated miRNA profiles and its molecular mechanisms underlying the induction of glioma cell death. By performing miRNA microarray and bioinformatics analyses, we observed that expression of 248 miRNAs was altered, including five significantly upregulated and 17 significantly downregulated miRNAs, in TMZ-treated U87MG cells. miR-128 expression levels were lower in different glioma cells and strongly associated with poor survival. TMZ treatment significantly upregulated miR-128 expression. TMZ significantly enhanced miR-128-1 promoter activity and transcriptionally regulated miR-128 levels through c-Jun N-terminal kinase 2/c-Jun pathways. The overexpression and knockdown of miR-128 expression significantly affected TMZ-mediated cell viability and apoptosis-related protein expression. Furthermore, the overexpression of miR-128 alone enhanced apoptotic death of glioma cells through caspase-3/9 activation, poly(ADP ribose) polymerase degradation, reactive oxygen species generation, mitochondrial membrane potential loss, and non-protective autophagy formation. Finally, we identified that key members in mammalian target of rapamycin (mTOR) signaling including mTOR, rapamycin-insensitive companion of mTOR, insulin-like growth factor 1, and PIK3R1, but not PDK1, were direct target genes of miR-128. TMZ inhibited mTOR signaling through miR-128 regulation. These results indicate that miR-128-inhibited mTOR signaling is involved in TMZ-mediated cytotoxicity. Our findings may provide a better understanding of cytotoxic mechanisms of TMZ involved in glioblastoma development.

MiR-31 and miR-128 regulates poliovirus receptor-related 4 mediated measles virus infectivity in tumors

Oncolytic measles virus strains are currently being evaluated in several clinical trials, as a promising novel oncolytic platform. Poliovirus receptor-related 4 (PVRL4) was recently identified as a potent measles virus (MV) receptor; however, its regulation is not yet understood. Increased levels of PVRL4 protein were observed in cell membrane, cytoplasm and nuclei of glioblastoma, breast and ovarian tumor clinical samples with no significant change in PVRL4 mRNA levels in glioblastoma and breast cancer compared with their corresponding control samples, suggesting that PVRL4 is likely post-transcriptionally regulated. Therefore, we sought to investigate the potential role of miRNAs in PVRL4 regulation and thus MV infectivity. We demonstrated that miR-31 and miR-128 can bind to the 3'UTR of PVRL4 and decrease PVRL4 levels while anti-miR-31/128 increase PVRL4 levels suggesting that PVRL4 is miRNA targeted. Furthermore, miR-31/128 expression levels were down-regulated in glioblastoma and breast tumor samples and showed significant negative correlations with PVRL4 levels. Infection with an MV strain that exclusively utilizes PVRL4 as its receptor showed that over-expression of miR-31/128 decreases MV infectivity while inhibition of the respective miRNAs via anti-miRs increase MV infectivity and reduce tumor size in mouse xenograft models of glioblastoma, breast and ovarian cancer. Additionally, miR-128 levels showed significant correlations with MV infection and in vivo anti-tumor effect, while MV infection increased miR-31 expression and thereby contributed to the observed decrease in PVRL4 levels. This study suggests that PVRL4 is post-transcriptionally regulated by miR-128 and miR-31 and harbors possible miRNA targets that could modulate MV infectivity and in turn enhance MV based oncolytic therapeutic strategies.

Leukemia inhibitory factor promotes EMT through STAT3-dependent miR-21 induction

Leukemia inhibitory factor (LIF) is a multi-function cytokine. Its role in cancer is not well-understood. Recent studies including ours show that LIF is frequently overexpressed in many types of human tumors and promotes the progression and metastasis of tumors. However, the underlying mechanism of LIF's promoting effects on tumor progression and metastasis is poorly defined. Epithelial-mesenchymal transition (EMT) plays an important role in tumor metastasis. This study reports that LIF promotes EMT in human tumor cells. Overexpression of LIF promotes tumor cells to acquire mesenchymal features, including morphological changes of cells from epithelial-like to mesenchymal-like, increased expression levels of mesenchymal markers and decreased expression of epithelial markers. Knockdown of endogenous LIF reverses EMT in cancer cells. We further identified that LIF induces the expression of microRNA-21 (miR-21), which in turn mediates the promoting effect of LIF on EMT. LIF induces miR-21 expression through the activation of STAT3. Importantly, blocking miR-21 function greatly abolished the promoting effect of LIF on EMT and the migration ability of cancer cells. Taken together, results from this study identified an important function and a novel underlying mechanism of LIF in EMT and tumor metastasis.

Up-regulation of miR-455-5p by the TGF-β-SMAD signalling axis promotes the proliferation of oral squamous cancer cells by targeting UBE2B

MicroRNAs (miRNAs) are involved in the tumourigenesis of various cancers by regulating their downstream targets. To identify the changes of miRNAs in oral squamous cell carcinoma (OSCC), we investigated the expression profiles of miRNAs in 40 pairs of OSCC specimens and their matched non-tumour epithelial tissues. Our data revealed higher miR-455-5p expression in the tumour tissues than in the normal tissues; the expression was also higher in oral cancer cell lines than in normal keratinocyte cell lines. MiR-455-5p knockdown reduced both the anchorage-independent growth and the proliferative ability of oral cancer cells, and these factors increased in miR-455-5p-overexpressing cells. Furthermore, by analysing the array data of patients with cancer and cell lines, we identified ubiquitin-conjugating enzyme E2B (UBE2B) as a target of miR-455-5p, and further validated this using 3'-untranslated region luciferase reporter assays and western blot analysis. We also demonstrated that UBE2B suppression rescued the impaired growth ability of miR-455-5p-knockdown cells. Furthermore, we observed that miR-455-5p expression was regulated, at least in part, by the transforming growth factor-β (TGF-β) pathway through the binding of SMAD3 to specific promoter regions. Notably, miR-455-5p expression was associated with the nodal status, stage, and overall survival in our patients, suggesting that miR-455-5p is a potential marker for predicting the prognosis of patients with oral cancer. In conclusion, we reveal that miR-455-5p expression is regulated by the TGF-β-dependent pathway, which subsequently leads to UBE2B down-regulation and contributes to oral cancer tumourigenesis. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

AurkA controls self-renewal of breast cancer-initiating cells promoting wnt3a stabilization through suppression of miR-128

AurkA overexpression was previously found in breast cancer and associated to its ability in controlling chromosome segregation during mitosis, however whether it may affect breast cancer cells, endorsed with stem properties (BCICs), is still unclear. Surprisingly, a strong correlation between AurkA expression and β-catenin localization in breast cancer tissues suggested a link between AurkA and Wnt signaling. In our study, AurkA knock-down reduced wnt3a mRNA and suppressed metastatic signature of MDA-MB-231 cells. As a consequence, the amount of BCICs and their migratory capability dramatically decreased. Conversely, wnt3a mRNA stabilization and increased CD44(+)/CD24(low/-) subpopulation was found in AurkA-overexpressing MCF7 cells. In vivo, AurkA-overexpressing primary breast cancer cells showed higher tumorigenic properties. Interestingly, we found that AurkA suppressed the expression of miR-128, inhibitor of wnt3a mRNA stabilization. Namely, miR-128 suppression realized after AurkA binding to Snail. Remarkably, a strong correlation between AurkA and miR-128 expression in breast cancer tissues confirmed our findings. This study provides novel insights into an undisclosed role for the kinase AurkA in self-renewal and migration of BCICs affecting response to cancer therapies, metastatic spread and recurrence. In addition, it suggests a new therapeutic strategy taking advantage of miR-128 to suppress AurkA-Wnt3a signaling.

BMI1: A Biomarker of Hematologic Malignancies

BMI1 oncogene is a catalytic member of epigenetic repressor polycomb group proteins. It plays a critical role in the regulation of gene expression pattern and consequently several cellular processes during development, including cell cycle progression, senescence, aging, apoptosis, angiogenesis, and importantly self-renewal of adult stem cells of several lineages. Preponderance of evidences indicates that deregulated expression of PcG protein BMI1 is associated with several human malignancies, cancer stem cell maintenance, and propagation. Importantly, overexpression of BMI1 correlates with therapy failure in cancer patients and tumor relapse. This review discusses the diverse mode of BMI1 regulation at transcriptional, posttranscriptional, and posttranslational levels as well as at various critical signaling pathways regulated by BMI1 activity. Furthermore, this review highlights the role of BMI1 as a biomarker and therapeutic target for several subtypes of hematologic malignancies and the importance to target this biomarker for therapeutic applications.

miR-128 regulates differentiation of hair follicle mesenchymal stem cells into smooth muscle cells by targeting SMAD2

Human hair follicle mesenchymal stem cells (hHFMSCs) are an important source of cardiovascular tissue engineering for their differentiation potential into smooth muscle cells (SMCs), yet the molecular pathways underlying such fate determination is unclear. MicroRNAs (miRNAs) are non-coding RNAs that play critical roles in cell differentiation. In present study, we found that miR-128 was remarkably decreased during the differentiation of hHFMSCs into SMCs induced by transforming growth factor-β1 (TGF-β1). Moreover, overexpression of miR-128 led to decreased expression of SMC cellular marker proteins, such as smooth muscle actin (SMA) and calponin, in TGF-β1-induced SMC differentiation. Further, we identified that miR-128 targeted the 3'-UTR of SMAD2 transcript for translational inhibition of SMAD2 protein, and knockdown of SMAD2 abrogated the promotional effect of antagomir-128 (miR-128 neutralizer) on SMC differentiation. These results suggest that miR-128 regulates the differentiation of hHFMSCs into SMCs via targeting SMAD2, a main transcription regulator in TGF-β signaling pathway involving SMC differentiation. The miR-128/SMAD2 axis could therefore be considered as a candidate target in tissue engineering and regenerative medicine for SMCs.

Transposable elements and miRNA: Regulation of genomic stability and plasticity

Transposable elements, the class of mobile DNA sequences that change their copies or positions within the genome have an ever increasing role in shaping the genetic and evolutionary landscape. Approximately half of the mammalian genome is composed of repetitive elements, including LINE-1 (L1) elements. Because of their ability to "copy and paste" into other regions of the genome, their activation represent an opportunity as well as a threat, as L1-induced mutations results in genomic instability and plasticity. On one hand L1 retrotransposition and integration fosters genomic diversity and on the other, de-repressed L1 functions as a driver of diseases such as cancer. The regulation of L1 is an area of intense research and novel epigenetic mechanisms have recently been discovered to now include DNA methylation, histone modifications, and miR-induced L1 silencing. During development, reprogramming and in transformed cells, specific classes of repetitive elements are upregulated, presumably due to the loss of epigenetic regulation in this process, increasing the risk of L1-induced mutations. Here we discuss how miR regulation of L1 activation fits into the complex picture of L1 repression in somatic cells and touch on some of the possible implications.

Breast cancer stem cells programs: enter the (non)-code

Breast tumors exhibit a hierarchical cellular organization driven by several subpopulations of cancer stem cells (CSCs). These breast CSC subpopulations are able to infinitely self-renew and to differentiate, giving rise to tumor heterogeneity. Accumulating evidence show that breast CSCs resist conventional therapies and i`nitiate tumor relapse. The development of anti-CSCs therapies may therefore greatly improve patient survival. A better elucidation of molecular circuitries involved in stemness would offer new relevant targets. Noncoding RNAs, especially microRNAs and long noncoding RNAs, are regulators of cell identity and are notably found deregulated in breast CSCs. This review will focus on noncoding RNAs involved in CSCs biology during breast cancer initiation, maintenance, therapeutic resistance and metastatic progression. Potential clinical applications using noncoding RNAs as biomarkers or therapies will be discussed.

A Perspective on the Role of microRNA-128 Regulation in Mental and Behavioral Disorders

MiRNAs are short, non-coding RNA molecules that regulate gene expression post-transcriptionally. Over the past decade, misregulated miRNA pathways have been associated with various diseases such as cancer, neurodegenerative diseases, and neurodevelopmental disorders. In this article, we aim to discuss the role played by miR-128 in neuropsychiatric disorders, and highlight potential target genes from an in silico analysis of predicted miR-128 targets. We also discuss the differences of target gene determination based on a bioinformatics or empirical approach. Using data from TargetScan and published reports, we narrowed the miR-128 target gene list to those that are known to be associated with neuropsychiatric disorders, and found that these genes can be classified into 29 gene clusters and are mostly enriched in cancer and MAPK signaling pathways. We also highlight some recent studies on several of the miR-128 targets which should be investigated further as potential candidate genes for therapeutic interventions.