Aberrant miRNA promoter methylation and EMT‐involving miRNAs in breast cancer metastasis: Diagnosis and therapeutic implications

Bidirectional crosstalk between the epithelial-mesenchymal transition and immunotherapy: A bibliometric study

Immunotherapy has recently attracted considerable attention. However, currently, a thorough analysis of the trends associated with the epithelial-mesenchymal transition (EMT) and immunotherapy is lacking. In this study, we used bibliometric tools to provide a comprehensive overview of the progress in EMT-immunotherapy research. A total of 1,302 articles related to EMT and immunotherapy were retrieved from the Web of Science Core Collection (WOSCC). The analysis indicated that in terms of the volume of research, China was the most productive country (49.07%, 639), followed by the United States (16.89%, 220) and Italy (3.6%, 47). The United States was the most influential country according to the frequency of citations and citation burstiness. The results also suggested that Frontiers in Immunotherapy can be considered as the most influential journal with respect to the number of articles and impact factors. "Immune infiltration," "bioinformatics analysis," "traditional Chinese medicine," "gene signature," and "ferroptosis" were found to be emerging keywords in EMT-immunotherapy research. These findings point to potential new directions that can deepen our understanding of the mechanisms underlying the combined effects of immunotherapy and EMT and help develop strategies for improving immunotherapy.

MiR-371-5p regulates trophoblast cell proliferation, migration, and invasion by directly targeting ZNF516

Despite its prevalence, preeclampsia (PE) remains unclear as to its etiology. Here, we aimed to investigate the mechanisms regulating differences in the gene expression of zinc-finger protein 516 (ZNF516) in the placenta. The expression of the placental ZNF516 gene and its association with critical clinical markers were verified, and a rigorous correlation analysis was conducted. With a dual-luciferase reporter gene assay, microRNA targeting the ZNF516 gene was predicted and confirmed. Finally, the molecular processes associated with ZNF516 were explored via microarray and bioinformatic analyses. In hypoxic conditions, miR-371-5p expression was reduced, resulting in ZNF516 expression being induced. Moreover, ZNF516 was shown to hinder trophoblast cell migration and invasion while enhancing trophoblast cell death in various in vitro cellular assays, such as cell counting kit-8, colony formation, wound healing, and Transwell assays. Our findings reveal a new regulatory network facilitated by ZNF516. ZNF516 overexpression inhibits trophoblast growth, movement, and penetration, potentially causing problems with placenta formation with the help of miR-371-5p suppression.

IL-6 regulates epithelial ovarian cancer EMT, invasion, and metastasis by modulating Let-7c and miR-200c through the STAT3/HIF-1α pathway

Interleukin-6 (IL-6) and hypoxia-inducible factor-1α (HIF-1α) play important roles in epithelial-mesenchymal transformation (EMT) and tumor development. Previous studies have demonstrated that IL-6 promotes EMT, invasion, and metastasis in epithelial ovarian cancer (EOC) cells by activating the STAT3/HIF-1α pathway. MicroRNA (miRNA) is non-coding small RNAs that also play an important role in tumor development. Notably, Let-7 and miR-200 families are prominently altered in EOC. However, whether IL-6 regulates the expression of Let-7 and miR-200 families through the STAT3/HIF-1α signaling to induce EMT in EOC remains poorly understood. In this study, we conducted in vitro and in vivo investigations using two EOC cell lines, SKOV3, and OVCAR3 cells. Our findings demonstrate that IL-6 down-regulates the mRNA levels of Let-7c and miR-200c while up-regulating their target genes HMGA2 and ZEB1 through the STAT3/HIF-1α signaling in EOC cells and in vivo. Additionally, to explore the regulatory role of HIF-1α on miRNAs, both exogenous HIF blockers YC-1 and endogenous high expression or inhibition of HIF-1α can be utilized. Both approaches can confirm that the downstream molecule HIF-1α inhibits the expression and function of Let-7c and miR-200c. Further mechanistic research revealed that the overexpression of Let-7c or miR-200c can reverse the malignant evolution of EOC cells induced by IL-6, including EMT, invasion, and metastasis. Consequently, our results suggest that IL-6 regulates the expression of Let-7c and miR-200c through the STAT3/HIF-1α pathway, thereby promoting EMT, invasion, and metastasis in EOC cells.

Construction of a prognostic model based on genome-wide methylation analysis of miRNAs for hepatocellular carcinoma

Aim: Using the methylation level of miRNA genes to develop a prognostic model for patients with hepatocellular carcinoma (HCC). Materials & methods: least absolute shrinkage and selection operator and multivariate Cox regression analyses were performed to develop a prognostic model. One miRNA in the model was selected for verification. Results: A prognostic model was developed using eight miRNAs. The areas under the curve for predicting overall survival at 1, 3 and 5 years were 0.75, 0.81 and 0.81. miR-223 was found to be hypomethylated in 160 HCC tissues, and its methylation level was associated with Barcelona Clinic Liver Cancer stages and the prognosis of patients with HCC. Conclusion: The prognostic model based on miRNA methylation levels has the capability to partially forecast the prognosis of patients with HCC.

NPHS2-6 drives cervical squamous cell carcinoma (CSCC) progression via hsa-miR-1323/SMC1B axis to activate PI3K-Akt pathway

PURPOSE

A substantial amount of evidence demonstrates suggests that long non-coding RNAs (lncRNAs) play a key role in the progression of various malignancies, cervical squamous cell carcinoma (CSCC) included. In our study, we deeply investigated the role and molecular mechanism of lncRNA NPHS2-6 in CSCC.

METHODS

The expression level of gene and protein expression were measured by qRT-PCR and western blot. To test the cell proliferation and cell metastasis ability, we carried out the CCK-8 experiment, clone formation assay, transwell assay and wound healing, respectively. The interactivity among NPHS2-6, miR-1323 and SMC1B were co demonstrated using the bioinformatics tool, dual-luciferase reporter system, and RNA pulldown assay. The subcutaneous tumor model of nude mice was established to verify the results of previous studies at the in vivo. NPHS2-6 was upregulated in CSCC tissues and cells.

RESULTS

NPHS2-6 deficiency significantly inhibited CSCC cell growth and EMT in vitro. In addition, NPHS2-6 deficiency also inhibited the growth of CSCC xenograft tumors in mice in vivo. Importantly, NPHS2-6 was a competing endogenous RNA (ceRNA) to increases SMC1B levels by binding to miR-1323, leading to activate the PI3K/Akt pathway, thereby exacerbating tumorigenesis of CSCC.

CONCLUSIONS

In conclusion, NPHS2-6/miR-1323/SMC1B/PI3K/Akt signaling accelerates the progression of CSCC, providing a new direction for the treatment strategy of CSCC.

EV-miRNA-Mediated Intercellular Communication in the Breast Tumor Microenvironment

Cancer research has prioritized the study of the tumor microenvironment (TME) as a crucial area of investigation. Understanding the communication between tumor cells and the various cell types within the TME has become a focal point. Bidirectional communication processes between these cells support cellular transformation, as well as the survival, invasion, and metastatic dissemination of tumor cells. Extracellular vesicles are lipid bilayer structures secreted by cells that emerge as important mediators of this cell-to-cell communication. EVs transfer their molecular cargo, including proteins and nucleic acids, and particularly microRNAs, which play critical roles in intercellular communication. Tumor-derived EVs, for example, can promote angiogenesis and enhance endothelial permeability by delivering specific miRNAs. Moreover, adipocytes, a significant component of the breast stroma, exhibit high EV secretory activity, which can then modulate metabolic processes, promoting the growth, proliferation, and migration of tumor cells. Comprehensive studies investigating the involvement of EVs and their miRNA cargo in the TME, as well as their underlying mechanisms driving tumoral capacities, are necessary for a deeper understanding of these complex interactions. Such knowledge holds promise for the development of novel diagnostic and therapeutic strategies in cancer treatment.

The RNA-Binding and RNA-Melting Activities of the Multifunctional Protein Nucleobindin 1

Nucleobindin 1 (NUCB1) is a ubiquitous multidomain protein that belongs to the EF-hand Ca2+-binding superfamily. NUCB1 interacts with Galphai3 protein, cyclooxygenase, amyloid precursor protein, and lipids. It is involved in stress response and human diseases. In addition, this protein is a transcription factor that binds to the DNA E-box motif. Using surface plasmon resonance and molecular beacon approaches, we first showed the RNA binding and RNA melting activities of NUCB1. We suggest that NUCB1 could induce local changes in structured RNAs via binding to the GGAUAU loop sequence. Our results demonstrate the importance of the multidomain structure of NUCB1 for its RNA-chaperone activity in vitro.

Mutual interaction of lncRNAs and epigenetics: focusing on cancer

Long noncoding RNAs are characterized as noncoding transcripts longer than 200 nucleotides in response to a variety of functions within the cells. They are involved in almost all cellular mechanisms so as epigenetics. Given that epigenetics is an important phenomenon, which participates in the biology of complex diseases, many valuable studies have been performed to demonstrate the control status of lncRNAs and epigenetics. DNA methylation and histone modifications as epigenetic mechanisms can regulate the expression of lncRNAs by affecting their coding genes. Reciprocally, the three-dimensional structure of lncRNAs could mechanistically control the activity of epigenetic-related enzymes. Dysregulation in the mutual interaction between epigenetics and lncRNAs is one of the hallmarks of cancer. These mechanisms are either directly or indirectly involved in various cancer properties such as proliferation, apoptosis, invasion, and metastasis. For instance, lncRNA HOTAIR plays a role in regulating the expression of many genes by interacting with epigenetic factors such as DNA methyltransferases and EZH2, and thus plays a role in the initiation and progression of various cancers. Conversely, the expression of this lncRNA is also controlled by epigenetic factors. Therefore, focusing on this reciprocated interaction can apply to cancer management and the identification of prognostic, diagnostic, and druggable targets. In the current review, we discuss the reciprocal relationship between lncRNAs and epigenetic mechanisms to promote or prevent cancer progression and find new potent biomarkers and targets for cancer diagnosis and therapy.

DNA methylation-induced ablation of miR-133a accelerates cancer aggressiveness in glioma through upregulating peroxisome proliferator-activated receptor γ

Emerging evidences suggest that miRNAs can be used as theranostic biomarkers for multiple cancers, including glioma. Thus, identification of novel miRNAs for glioma treatment and prognosis becomes necessary and urgent. Here, by analyzing miRNA expression profiles in the glioma and para-cancer tissues by miRNA microarray and verified by RT-PCR, we found that miR-133a was significantly downregulated in the cancerous tissues, and patients with low-expressed miR-133a levels predicted an unfavorable prognosis. The following functional experiments confirmed that overexpression of miR-133a restrained cell proliferation and colony formation abilities, and induced cell cycle arrest to restrain cancer progression in glioma cells. Then, the underlying mechanisms were uncovered, and the peroxisome proliferator-activated receptor γ (PPARγ, PPARG) was verified as the downstream target of miR-133a. Mechanistically, miR-133a negatively regulated PPARG expressions by binding to its 3' untranslated regions (3'UTR). The following rescuing experiments evidenced that miR-133a overexpression-induced anti-cancer effects in glioma cells were abrogated by upregulating PPARγ. Interestingly, we noticed that the promoter region of miR-133a was hypermethylated, and removal of DNA methylation by 5-Azacytidine (AZA) significantly increased the expression levels of miR-133a in glioma cells. Taken together, we concluded that DNA-methylation-induced miR-133a silence contributed to cancer progression in glioma through upregulating PPARγ, and firstly identified the DNA-methylation-regulated miR-133a/PPARG axis as the novel indicators for glioma treatment and prognosis.

The contributing factors of resistance or sensitivity to epigenetic drugs in the treatment of AML

Drug resistance is the drug-effectiveness reduction in treatment and is a serious problem in oncology and infections. In oncology, drug resistance is a complicated process resulting from enhancing the function of a pump that transports drugs out of tumor cells, or acquiring mutations in drug target. Surprisingly, most drugs are very effective in the early stages, but the response to the drug wears off over time and resistance eventually develops. Drug resistance is caused by genetic and epigenetic changes that affect cancer cells and the tumor environment. The study of inherited changes in the phenotype without changes in the DNA sequence is called epigenetics. Because of reversible changes in epigenetics, they are an attractive target for therapy. Some of these epigenetic drugs are effective in treating cancers like acute myeloid leukemia (AML), which is characterized by the accumulation and proliferation of immature hematopoietic cells in the blood and bone marrow. In this article, we outlined the various contributing factors involved in resistance or sensitivity to epigenetic drugs in the treatment of AML.

CRISPR/Cas9 application in cancer therapy: a pioneering genome editing tool

The progress of genetic engineering in the 1970s brought about a paradigm shift in genome editing technology. The clustered regularly interspaced short palindromic repeats/CRISPR associated protein 9 (CRISPR/Cas9) system is a flexible means to target and modify particular DNA sequences in the genome. Several applications of CRISPR/Cas9 are presently being studied in cancer biology and oncology to provide vigorous site-specific gene editing to enhance its biological and clinical uses. CRISPR's flexibility and ease of use have enabled the prompt achievement of almost any preferred alteration with greater efficiency and lower cost than preceding modalities. Also, CRISPR/Cas9 technology has recently been applied to improve the safety and efficacy of chimeric antigen receptor (CAR)-T cell therapies and defeat tumor cell resistance to conventional treatments such as chemotherapy and radiotherapy. The current review summarizes the application of CRISPR/Cas9 in cancer therapy. We also discuss the present obstacles and contemplate future possibilities in this context.

Elucidating miRNA Function in Cancer Biology via the Molecular Genetics' Toolbox

Micro-RNA (miRNAs) are short non-coding RNAs of about 18-20 nucleotides in length and are implicated in many cellular processes including proliferation, development, differentiation, apoptosis and cell signaling. Furthermore, it is well known that miRNA expression is frequently dysregulated in many cancers. Therefore, this review will highlight the various mechanisms by which microRNAs are dysregulated in cancer. Further highlights include the abundance of molecular genetics tools that are currently available to study miRNA function as well as their advantages and disadvantages with a special focus on various CRISPR/Cas systems This review provides general workflows and some practical considerations when studying miRNA function thus enabling researchers to make informed decisions in regards to the appropriate molecular genetics tool to be utilized for their experiments.

Non-Coding RNAs in the Crosstalk between Breast Cancer Cells and Tumor-Associated Macrophages

Non-coding RNAs (ncRNAs) play a pivotal role in regulating the tumor microenvironment (TME) by controlling gene expression at multiple levels. In tumors, ncRNAs can mediate the crosstalk between cancer cells and other cells in the TME, such as immune cells, stromal cells, and endothelial cells, influencing tumor development and progression. Tumor-associated macrophages (TAMs) are among the most abundant inflammatory cells infiltrating solid cancers that promote tumorigenesis, and their infiltration correlates with a poor prognosis in many tumors. Cancer cells produce different ncRNAs that orchestrate TAM recruitment and polarization toward a tumor-promoting phenotype. Tumor-reprogrammed macrophages shape the TME by promoting angiogenesis and tissue remodeling, and suppressing the anti-tumor activity of adaptive immune cells. TAMs can also produce ncRNA molecules that boost cancer cell proliferation and direct their phenotype and metabolic changes facilitating cancer progression and metastasis. This review will focus on the crosstalk between cancer cells and TAMs mediated by microRNAs and long non-coding RNAs during breast cancer (BC) initiation and progression.

Laboratory methods to decipher epigenetic signatures: a comparative review

Epigenetics refers to nucleotide sequence-independent events, and heritable changes, including DNA methylation and histone modification (as the two main processes), contributing to the phenotypic features of the cell. Both genetics and epigenetics contribute to determining the outcome of regulatory gene expression systems. Indeed, the flexibility of epigenetic effects and stability of genetic coding lead to gene regulation complexity in response signals. Since some epigenetic changes are significant in abnormalities such as cancers and neurodegenerative diseases, the initial changes, dynamic and reversible properties, and diagnostic potential of epigenomic phenomena are subject to epigenome-wide association studies (EWAS) for therapeutic aims. Based on recent studies, methodological developments are necessary to improve epigenetic research. As a result, several methods have been developed to explore epigenetic alterations at low, medium, and high scales, focusing on DNA methylation and histone modification detection. In this research field, bisulfite-, enzyme sensitivity- and antibody specificity-based techniques are used for DNA methylation, whereas histone modifications are gained based on antibody recognition. This review provides a mechanism-based understanding and comparative overview of the most common techniques for detecting the status of epigenetic effects, including DNA methylation and histone modifications, for applicable approaches from low- to high-throughput scales.

The related miRNAs involved in doxorubicin resistance or sensitivity of various cancers: an update

Doxorubicin (DOX) is an effective chemotherapy agent against a wide variety of tumors. However, intrinsic or acquired resistance diminishes the sensitivity of cancer cells to DOX, which leads to a cancer relapse and treatment failure. Resolutions to this challenge includes identification of the molecular pathways underlying DOX sensitivity/resistance and the development of innovative techniques to boost DOX sensitivity. DOX is classified as a Topoisomerase II poison, which is cytotoxic to rapidly dividing tumor cells. Molecular mechanisms responsible for DOX resistance include effective DNA repair and resumption of cell proliferation, deregulated development of cancer stem cell and epithelial to mesenchymal transition, and modulation of programmed cell death. MicroRNAs (miRNAs) have been shown to potentiate the reversal of DOX resistance as they have gene-specific regulatory functions in DOX-responsive molecular pathways. Identifying the dysregulation patterns of miRNAs for specific tumors following treatment with DOX facilitates the development of novel combination therapies, such as nanoparticles harboring miRNA or miRNA inhibitors to eventually prevent DOX-induced chemoresistance. In this article, we summarize recent findings on the role of miRNAs underlying DOX sensitivity/resistance molecular pathways. Also, we provide latest strategies for utilizing deregulated miRNA patterns as biomarkers or miRNAs as tools to overcome chemoresistance and enhance patient's response to DOX treatment.

MicroRNA-3935 promotes human trophoblast cell epithelial-mesenchymal transition through tumor necrosis factor receptor-associated factor 6/regulator of G protein signaling 2 axis

BACKGROUND

Insufficient migration and invasion during trophoblast epithelial-mesenchymal transition (EMT) results in the occurrence and development of preeclampsia (PE), and our previous study has screened 52 miRNAs, whose expression levels are altered in the placental samples from PE patients, compared with the normal group. Among those, miR-3935 is one of the miRNAs being most significantly down-regulated, indicating its involvement in PE. However, the exact effect and molecular mechanisms remain unknown.

METHODS

In the present study, we investigate the roles and underlying mechanisms of miR-3935 in trophoblast EMT by use of the human extra-villous trophoblast cell line HTR-8/SVneo as well as human placental tissues and maternal blood samples obtained from 15 women with normal pregnancies and 15 women with PE. Experimental methods include transfection, quantitative reverse transcription-PCR (qRT-PCR), western blot, immunofluorescence staining, dual-luciferase assays, in vitro invasion and migration assays, RNA-Seq analysis, bisulfite sequencing and immunohistochemistry staining.

RESULTS

MiR-3935 expression is significantly decreased in both placentas and peripheral blood specimens of PE, and functionally, miR-3935 promotes EMT of trophoblast cells. Mechanistically, TRAF6 is identified to be a direct target of miR-3935 and TRAF6 exerts its negative effect on EMT of trophoblast cells by inhibition of RGS2, which down-regulates the methylation status of promoter of CDH1 gene that encodes E-Cadherin protein through induction of ALKBH1, resulting in increase of E-Cadherin and subsequently insufficient trophoblast EMT.

CONCLUSIONS

Together these results uncover a hitherto uncharacterized role of miR-3935/TRAF6/RGS2 axis in the function of human trophoblasts, which may pinpoint the molecular pathogenesis of PE and may be a prognostic biomarker and therapeutic target for such obstetrical diseases as PE.

Magic and mystery of microRNA-32

MicroRNAs (miRNAs) are a group of endogenous, small (∼22 nts in length) noncoding RNA molecules that function specifically by base pairing with the mRNA of genes and regulate gene expression at the post-transcriptional level. Alterations in miR-32 expression have been found in numerous diseases and shown to play a vital role in cell proliferation, apoptosis, oncogenesis, invasion, metastasis and drug resistance. MiR-32 has been documented as an oncomiR in the majority of related studies but has been also verified as a tumour suppressor miRNA in conflicting reports. Moreover, it has a crucial role in metabolic and cardiovascular disorders. This review provides an in-depth look into the most recent finding regarding miR-32, which is involved in the expression, regulation and functions in different diseases, especially tumours. Additionally, this review outlines novel findings suggesting that miR-32 may be useful as a noninvasive biomarker and as a targeted therapeutic in several diseases.

Epigenetic Regulation of Breast Cancer Stem Cells Contributing to Carcinogenesis and Therapeutic Implications

Globally, breast cancer has remained the most commonly diagnosed cancer and the leading cause of cancer death among women. Breast cancer is a highly heterogeneous and phenotypically diverse group of diseases, which require different selection of treatments. Breast cancer stem cells (BCSCs), a small subset of cancer cells with stem cell-like properties, play essential roles in breast cancer progression, recurrence, metastasis, chemoresistance and treatments. Epigenetics is defined as inheritable changes in gene expression without alteration in DNA sequence. Epigenetic regulation includes DNA methylation and demethylation, as well as histone modifications. Aberrant epigenetic regulation results in carcinogenesis. In this review, the mechanism of epigenetic regulation involved in carcinogenesis, therapeutic resistance and metastasis of BCSCs will be discussed, and finally, the therapies targeting these biomarkers will be presented.

Recent progress of graphene oxide-based multifunctional nanomaterials for cancer treatment

Background

In the last decade, graphene oxide-based nanomaterials, such as graphene oxide (GO) and reduced graphene oxide (rGO), have attracted more and more attention in the field of biomedicine. Due to the versatile surface functionalization, ultra-high surface area, and excellent biocompatibility of graphene oxide-based nanomaterials, which hold better promise for potential applications than among other nanomaterials in biomedical fields including drug/gene delivery, biomolecules detection, tissue engineering, especially in cancer treatment.

Results

Here, we review the recent progress of graphene oxide-based multifunctional nanomaterials for cancer treatment. A comprehensive and in-depth depiction of unique property of graphene oxide-based multifunctional nanomaterials is first interpreted, with particular descriptions about the suitability for applying in cancer therapy. Afterward, recently emerging representative applications of graphene oxide-based multifunctional nanomaterials in antitumor therapy, including as an ideal carrier for drugs/genes, phototherapy, and bioimaging, are systematically summarized. Then, the biosafety of the graphene oxide-based multifunctional nanomaterials is reviewed.

Conclusions

Finally, the conclusions and perspectives on further advancing the graphene oxide-based multifunctional nanomaterials toward potential and versatile development for fundamental researches and nanomedicine are proposed.

Graphic abstract

The expression of miR-513c and miR-3163 was downregulated in tumor tissues compared with normal adjacent tissue of patients with breast cancer

BACKGROUND

Breast cancer (BC) is the most invasive cancer with different subtypes that its metabolism is unique compared with normal cells. Glutamine is considered critical nutrition that many cancer cells, particularly BC cells, are dependent on it for growth and proliferation. Therefore, targeting glutamine metabolism, especially enzymes that are related to this pathway, can be beneficial to design anti-cancer agents. Recent evidence has shown that microRNAs (miRNAs), with a short length and single-strand properties, play a prominent role in regulating the genes related to glutamine metabolism, which may control the development of cancer.

METHODS

In silico analysis confirmed that miR-513c and miR-3163 might be involved in glutamine metabolism. The expression level of these two miRNAs was evaluated in eighty BC tissues and normal adjacent tissues. Furthermore, GSE38167, GSE38867, GSE42128, GSE45666, and GSE53179 were employed from gene expression omnibus (GEO). The Limma package was utilized to identify differentially expressed miRNAs (DEMs) of mentioned datasets to evaluate miR-513c and miR-3163 expression. Further, in silico analysis was utilized to predict the potential biological processes and molecular pathways of miR-513c and miR-3163, based on their target genes.

RESULTS

In silico studies revealed top categories of biological processes and cellular pathways that might play a critical role in metabolism reprogramming and cancer development and were target genes for miR-513c and miR-3163. The current study showed that miR-513c (p value = 0.02062 and FC =  - 2.3801) and miR-3163 (p value = 0.02034 and FC =  - 2.3792) were downregulated in tumor tissues compared to normal adjacent tissues. The analysis of GEO microarray datasets showed that miR-513c was downregulated in GSE38167, GSE38867, GSE42128, GSE45666 and GSE53179, whereas there was a significant downregulation of miR-3163 in only two studies, including GSE38867 and GSE42128 that they were in accordance with our experimental results. Furthermore, the subgroup analysis did not show any substantial relationship between expression levels of these two miRNAs and factors such as age, family history of cancer, and abortion history.

CONCLUSION

MiR-513c and miR-3163 were downregulated in BC tissues, which might serve as tumor suppressors. They are suggested as potential therapeutic targets for patients with BC.

Calycosin inhibits breast cancer cell migration and invasion by suppressing EMT via BATF/TGF-β1

In this study, we investigated the effects of calycosin on breast cancer cell progression and their underlying mechanisms. Calycosin dose- and time-dependently inhibited proliferation, migration, and invasion by T47D and MCF-7 breast cancer cells by downregulating basic leucine zipper ATF-like transcription factor (BATF) expression. Moreover, BATF promoted breast cancer cell migration and invasiveness by increasing TGFβ1 mRNA and protein levels. Bioinformatics analysis, dual luciferase reporter assays, and chromatin immunoprecipitation assays confirmed the presence of BATF-binding sites in the promoter sequence of TGFβ1 gene. Calycosin treatment inhibited epithelial-mesenchymal transition (EMT) of breast cancer cells by significantly increasing E-cadherin levels and decreasing N-cadherin, Vimentin, CD147, MMP-2, and MMP-9 levels through downregulation of BATF and TGFβ1. TGFβ1 knockdown reduced the migration and invasiveness of BATF-overexpressing breast cancer cells, whereas incubation with TGFβ1 enhanced the migration and invasiveness of calycosin-treated breast cancer cells. Our findings demonstrated that calycosin inhibited EMT and progression of breast cancer cells by suppressing BATF/TGFβ1 signaling. This suggests calycosin would be a promising therapeutic option for breast cancer patients.

Cancer stem cell-targeted therapeutic approaches for overcoming trastuzumab resistance in HER2-positive breast cancer

Application of the anti-HER2 drug trastuzumab has significantly improved the prognosis of patients with the HER2-positive subtype of breast cancer. However, 50% of patients with HER2 amplification relapse due to trastuzumab resistance. Accumulating evidence indicates that breast cancer is driven by a small subset of cancer-initiating cells or breast cancer stem cells (BCSCs), which have the capacity to self-renew and differentiate to regenerate the tumor cell hierarchy. Increasing data suggest that BCSCs are resistant to conventional therapy, including chemotherapy, radiotherapy, and endocrine therapy, which drives distant metastasis and breast cancer relapse. In recent years, the trastuzumab resistance of breast cancer has been closely related to the prevalence of BCSCs. Here, our primary focus is to discuss the role of epithelial-mesenchymal transition (EMT) of BCSCs in the setting of trastuzumab resistance and approaches of reducing or eradicating BCSCs in HER2-positive breast cancer.

LncRNA-miRNA axes in breast cancer: Novel points of interaction for strategic attack

Therapeutic effectiveness in breast cancer can be limited by the underlying mechanisms of pathogenesis, including epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs) and drug resistance. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are master regulators of gene expression and are functionally important mediators in these mechanisms of pathogenesis. Intricate crosstalks between these non-coding RNAs form complex regulatory networks of post-transcriptional gene regulation. Depending on the specific lncRNA/miRNA interaction, the lncRNA-miRNA axis can have tumor suppressor or oncogenic effects, thus defining the lncRNA-miRNA axis is important for determining targetability. Herein, we summarize the current literature describing lncRNA-miRNA interactions that are critical in the molecular mechanisms that regulate EMT, CSCs and drug resistance in breast cancer. Further, we review both the well-studied and potential novel mechanisms of lncRNA-miRNA interactions in breast cancer.

Comprehensive upstream and downstream regulatory analyses identify miR-675-3p as a potential prognostic biomarker in melanoma

This study assessed miR-675-3p-related regulatory mechanisms in melanoma and the clinical relevance of such regulatory activities. We downloaded miRNA mature strand expression RNA-Seq, phenotypic, and DNA methylation data pertaining to the TCGA Melanoma cohort. Differentially expressed miRNAs (DEMs) between metastatic and primary melanoma patient tissues were then identified, and miR-675-3p expression in melanoma patient peripheral blood was confirmed using the GSE20994 GEO dataset, while its expression in melanoma cell lines was evaluated via qRT-RCR. The clinical and prognostic implications of miR-675-3p in melanoma were assessed, and miR-675-3p target genes were identified using bioinformatics tools. Functional roles of this miRNA were explored via Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. We identified 3 and 22 miRNAs that were up- and downregulated, respectively, in metastatic melanoma samples relative to primary melanoma samples. Upregulation of miR-675-3p was associated with poorer overall patient survival, tumor histologic grade, and Clark's level. Consistently, miR-675-3p was also overexpressed in the peripheral blood of melanoma patients relative to healthy controls, and in melanoma cell lines relative to control cells. Gene regulatory networks indicated that 32 transcription factors control miR-675-3p expression, and that it, in turn, regulates 10 target genes. KEGG analyses indicated that these genes were associated with cell cycle, transcriptional misregulation in cancer, TGF-beta signaling, and HIF-1 signaling pathways. Gain-of-function assays revealed that miR-675-3p could promote cell proliferation via accelerating cell cycle progression. Western blotting results indicated that miR-675-3p could active TGF-beta and HIF-1 signaling. Through upstream and downstream analyses of miR-675-3p-related regulatory activity, we confirmed that this miRNA participates in key melanoma-related processes and offers value as a prognostic biomarker in melanoma patients.

Role of Exosomes in the Progression, Diagnosis, and Treatment of Gliomas

Gliomas are the most common primary malignant brain tumors associated with a low survival rate. Even after surgery, radiotherapy, and chemotherapy, gliomas still have a poor prognosis. Extracellular vesicles are a heterogeneous group of cell-derived membranous structures. Exosomes are a type of extracellular vesicles, their size ranges from 30 nm to 100 nm. Recent studies have proved that glioma cells could release numerous exosomes; therefore, exosomes have gained increasing attention in glioma-related research.

Recent studies have confirmed the importance of extracellular vesicles, particularly exosomes, in the development of brain tumors, including gliomas. Exosomes mediate intercellular communication in the tumor microenvironment by transporting biomolecules (proteins, lipids, deoxyribonucleic acid, and ribonucleic acid); thereby playing a prominent role in tumor proliferation, differentiation, metastasis, and resistance to chemotherapy or radiation. Given their nanoscale size, exosomes can traverse the blood-brain barrier and promote tumor progression by modifying the tumor microenvironment. Based on their structural and functional characteristics, exosomes are demonstrating their value not only as diagnostic and prognostic markers, but also as tools in therapies specifically targeting glioma cells.

Therefore, exosomes are a promising therapeutic target for the diagnosis, prognosis, and treatment of malignant gliomas. More research will be needed before exosomes can be used in clinical applications. Here, we describe the exosomes, their morphology, and their roles in the diagnosis and progression of gliomas. In addition, we discuss the potential of exosomes as a therapeutic target/drug delivery system for patients with gliomas.

Effect of lncRNA WT1-AS regulating WT1 on oxidative stress injury and apoptosis of neurons in Alzheimer's disease via inhibition of the miR-375/SIX4 axis

Objective: To study the effect of lncRNA WT1-AS on oxidative stress injury (OSI) and apoptosis of neurons in Alzheimer's disease (AD) and its specific mechanisms related to the microRNA-375 (miR-375)/SIX4 axis and WT1 expression.

Results: After bioinformatic prediction, WT1-AS was found to be downregulated in Aβ_25-35treated SH-SY5Y cells, and WT1-AS overexpression inhibited WT1 expression. WT1 could target miR-375 to promote its expression. miR-375 bound to SIX4, and miR-375 overexpression inhibited SIX4 expression. WT1-AS inhibited OSI and apoptosis, while WT1 and miR-375 overexpression or SIX4 silencing reversed the WT1-AS effect on OSI and apoptosis. In vivo experiments revealed that WT1-AS improved learning/memory abilities and inhibited OSI and apoptosis in AD mice.

Conclusion: Overexpression of WT1-AS can inhibit the miR-375/SIX4 axis, OSI and neuronal apoptosis in AD by inhibiting WT1 expression.

Methods: Related lncRNAs were identified, and miR-375 downstream targets were predicted. WT1-AS, WT1, miR-375 and SIX4 expression was detected in a cell model induced by Aβ_25-35. The binding of WT1 with miR-375 and that of miR-375 with SIX4 were further confirmed. Adenosine triphosphate (ATP), reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and lactate dehydrogenase (LDH) activities, and apoptosis levels were tested after mitochondrial membrane potential observation. Learning/memory abilities and neuronal apoptosis were tested in a mouse model.

LNA Inhibitor in microRNA miR-23b as a Potential Anti-proliferative Option in Human Hepatocellular Carcinoma

PURPOSE

Dysregulation of microRNAs (miRNAs) has been shown to be involved in the pathogenesis and progression of many malignancies. Human hepatocellular carcinoma (HCC) is one of the most common cancers worldwide and the third cause of cancer-related deaths. Recent data suggest that microRNA-23b (miR-23b) is significantly high in different types of cancer, specifically human hepatocellular carcinoma. Locked nucleic acid (LNA)-modified oligonucleotides have recently been suggested as a novel approach for targeting miRNAs as antisense-based gene silencing. The aim of this study was to explore the functional role of LNA-anti-miR-23b in a HepG2 (hepatocarcinoma) cell line.

METHODS

HepG2 cells were transfected with LNA-anti-miR-23b for 24, 48, and 72 h. Quantitative real-time reverse transcriptase-PCR (qRT-PCR) was performed to assess miR-23b expression by LNA-anti-miR-23b. The viability of the cells was evaluated by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay.

RESULTS

LNA-anti-miR-23b was successfully transfected into human HepG2 cells and suppressed the miR-23b. LNA-anti-miR-23b reduced the invasive behaviors of HepG2 cells after 24 h, compared to untreated cells and scrambled LNA-transfected cells, and this effect was more pronounced after 72 h.

CONCLUSIONS

Our findings suggest that inhibition of miR-23b could be used as a novel approach in inhibition of HCC proliferation.

Significant association of PKM2 and NQO1 proteins with poor prognosis in breast cancer

Pyruvate kinase M2 (PKM2) and NAD(P)H:quinone oxidoreductase-1 (NQO1) have been known to play significant functions in tumorigenesis and development. The association between PKM2 and NQO1 in breast cancer continues, however, to be unclear. In the present study, according to UALCAN and GEPIA database, the mRNA levels of PKM2 and NQO1 in breast primary tumor were significantly higher compared to normal breast tissue. Consonant with these findings, increased expression of both PKM2 and NQO1 were detected in clinical samples and BC cell lines. More importantly, consolidated high expression of NQO1 and PKM2 were obtained to be related with worse clinical stage, relapse, shorter relapse free survival (RFS), and poorer overall survival (OS) in human breast cancer. We subsequently found that knockdown of NQO1 reduced the protein level of PKM2 significantly. Moreover, deletion of PKM2 significantly reduced colony formation, migration and invasion of BC cells. A positive correlation between PKM2 and NQO1 expression was identified by immunohistochemical analyses of 108 specimens of breast cancer patients (rs = 0.60, P = 0.00). Finally, endogenous Co-IP demonstrated that PKM2 and NQO1 interact in breast cancer cells. The results of this study suggest that the correlation between NQO1 and PKM2 might play a critical role during breast tumourigenesis and serve as novel diagnostic biomarkers for breast cancer.

One-step isothermal RNA detection with LNA-modified MNAzymes chaperoned by cationic copolymer

RNA detection permits early diagnosis of several infectious diseases and cancers, which prevent propagation of diseases and improve treatment efficacy. However, standard technique for RNA detection such as reverse transcription-quantitative polymerase chain reaction has complicated procedure and requires well-trained personnel and specialized lab equipment. These shortcomings limit the application for point-of-care analysis which is critical for rapid and effective disease management. The multicomponent nucleic acid enzymes (MNAzymes) are one of the promising biosensors for simple, isothermal and enzyme-free RNA detection. Herein, we demonstrate simple yet effective strategies that significantly enhance analytical performance of MNAzymes. The addition of the cationic copolymer and structural modification of MNAzyme significantly enhanced selectivity and activity of MNAzymes by 250 fold and 2,700 fold, respectively. The highly simplified RNA detection system achieved a detection limit of 73 fM target concentration without additional amplification. The robustness of MNAzyme in the presence of non-target RNA was also improved. Our finding opens up a route toward the development of an alternative rapid, sensitive, isothermal, and protein-free RNA diagnostic tool, which expected to be of great clinical significance.

Downregulation of miR-205 contributes to epithelial-mesenchymal transition and invasion in triple-negative breast cancer by targeting HMGB1-RAGE signaling pathway

Our aim was to study the regulatory molecule networks involved in the epithelial-to-mesenchymal transition and thus promoting the early onset of metastasis in triple-negative breast cancer (TNBC). Forty pairs of human TNBC and their adjacent normal breast tissues were analyzed by real-time PCR and immunochemistry to demonstrate the correlation between the miR-205 expression and clinicopathological characteristics. In vitro, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, cell migration, and invasion assay were used to detect the cell growth and invasive ability of TNBC cells after upregulation or downregulation of miR-205 expression. Luciferase reporter assay was used to confirm the potential target directly influenced by miR-205. Our results showed that miR-205 abnormal expression may be involved and associated with the biological traits of TNBC. Ectopic expression of miR-205 not only inhibited cell growth, but also suppressed migration and invasion of mesenchymal-like TNBC cells. In addition, we found that overexpression of miR-205 significantly suppressed HMGB1 by binding its 3′-untranslated region, and that miR-205 was inversely correlated with the expression of HMGB1 and RAGE in cell lines and clinical samples. Our study illustrated that miR-205 was a tumor suppressor in TNBC, which attenuated the viability and the acquisition of the epithelial-to-mesenchymal transition phenotype TNBC cells at least partially exerted through targeting of HMGB1–RAGE signaling pathway.

The role of epigenetics and non-coding RNAs in autophagy: A new perspective for thorough understanding

Autophagy is a major self-degradative intracellular process required for the maintenance of homeostasis and promotion of survival in response to starvation. It plays critical roles in a large variety of physiological and pathological processes. On the other hand, aberrant regulation of autophagy can lead to various cancers and neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and Crohn's disease. Emerging evidence strongly supports that epigenetic signatures, related non-coding RNA profiles, and their cross-talking are significantly associated with the control of autophagic responses. Therefore, it may be helpful and promising to manage autophagic processes by finding valuable markers and therapeutic approaches. Although there is a great deal of information on the components of autophagy in the cytoplasm, the molecular basis of the epigenetic regulation of autophagy has not been completely elucidated. In this review, we highlight recent research on epigenetic changes through the expression of autophagy-related genes (ATGs), which regulate autophagy, DNA methylation, histone modifications as well as non-coding RNAs, including long non-coding RNAs (lncRNAs), microRNAs (miRNAs) and their relationship with human diseases, that play key roles in causing autophagy-related diseases.

Machine Learning-Based Ensemble Recursive Feature Selection of Circulating miRNAs for Cancer Tumor Classification

Circulating microRNAs (miRNA) are small noncoding RNA molecules that can be detected in bodily fluids without the need for major invasive procedures on patients. miRNAs have shown great promise as biomarkers for tumors to both assess their presence and to predict their type and subtype. Recently, thanks to the availability of miRNAs datasets, machine learning techniques have been successfully applied to tumor classification. The results, however, are difficult to assess and interpret by medical experts because the algorithms exploit information from thousands of miRNAs. In this work, we propose a novel technique that aims at reducing the necessary information to the smallest possible set of circulating miRNAs. The dimensionality reduction achieved reflects a very important first step in a potential, clinically actionable, circulating miRNA-based precision medicine pipeline. While it is currently under discussion whether this first step can be taken, we demonstrate here that it is possible to perform classification tasks by exploiting a recursive feature elimination procedure that integrates a heterogeneous ensemble of high-quality, state-of-the-art classifiers on circulating miRNAs. Heterogeneous ensembles can compensate inherent biases of classifiers by using different classification algorithms. Selecting features then further eliminates biases emerging from using data from different studies or batches, yielding more robust and reliable outcomes. The proposed approach is first tested on a tumor classification problem in order to separate 10 different types of cancer, with samples collected over 10 different clinical trials, and later is assessed on a cancer subtype classification task, with the aim to distinguish triple negative breast cancer from other subtypes of breast cancer. Overall, the presented methodology proves to be effective and compares favorably to other state-of-the-art feature selection methods.

ZNF281-miR-543 Feedback Loop Regulates Transforming Growth Factor-β-Induced Breast Cancer Metastasis

Breast cancer is the most common malignancy, and metastasis is the main cause of cancer-associated mortality in women worldwide. Transforming growth factor-β (TGF-β) signaling, an inducer of epithelial-to-mesenchymal transition (EMT), plays an important role in breast cancer metastasis. Abnormal expression of miR-543 is associated with tumorigenesis and progression of various human cancers; however, the knowledge about the role of miR-543 in breast cancer metastasis is still unknown. In this study, we demonstrated that miR-543 inhibits the EMT-like phenotype and TGF-β-induced breast cancer metastasis both in vitro and in vivo by targeting ZNF281. ZNF281 transactivates the EMT-related transcription factor ZEB1 and Snail. Furthermore, both ZEB1 and Snail can transcriptionally suppress miR-543 expression. Taken together, our data uncover the ZNF281-miR-543 feedback loop and provide a mechanism to extend the understanding of TGF-β network complexity.

Abnormal DNA methylation patterns in patients with infection‑caused leukocytopenia based on methylation microarrays

The present study aimed to investigate the association between gene methylation and leukocytopenia from the perspective of gene regulation. A total of 30 patients confirmed as having post-infection leukocytopenia at People's Hospital of Xinjiang Uygur Autonomous Region between January 2016 and June 2017 were successively recruited as the leukocytopenia group; 30 patients with post-infection leukocytosis were enrolled as the leukocytosis group. In addition, 30 healthy volunteers who received a health examination at the hospital during the same period were included as the normal control group. In each group, four individuals were randomly selected for whole genome methylation screening. After selection of key methylation sites, the remaining samples in each group were used for verification using matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The levels of serum complement factors C3 and C5 in the leukocytopenia group were significantly lower than those in the other two groups (P<0.05). According to whole-genome DNA methylation detection, 66 and 27 methylation loci may be associated with leukocytopenia and leukocytosis, respectively. Most of these abnormal loci are located on chromosomes 2, 6, 7, 1, 17 and 11. The rates of WW domain containing E3 ubiquitin protein ligase 2 gene methylation at cytosine-phosphate-guanine (CpG)_1, CpG_5/6 and CpG_7 in the leukocytopenia group were higher than in the other two groups (P<0.05); the rate of AKT2 CpG_1 methylation was higher in the leukocytopenia group than in the other two groups (P<0.05); the rate of calcium-binding atopy-related autoantigen 1 gene CpG_2 methylation was higher in the leukocytosis group than in the normal control group (P<0.05); and the rate of NADPH oxidase 5 gene CpG_3 methylation was higher in the leukocytosis group than in the normal control group (P<0.05). Chemotactic factor secretion and cell migration abnormalities, ubiquitination modification disorders and reduced oxidative burst may participate in infection-complicated leukocytopenia. The results of this study shed new light on the molecular biological mechanisms of infection-complicated leukocytopenia and provide novel avenues for diagnosis and treatment.

Tumor Suppressor microRNA-138 Suppresses Low-Grade Glioma Development and Metastasis via Regulating IGF2BP2

Background

Low-grade gliomas (LGG), approximately constitute one-third of all types of gliomas, are prone to relapse and metastasis. MicroRNA-138 (miR-138) is reported to be dysregulated in diverse human tumors and mainly function as a tumor suppressor. In this study, we analyzed the expression profile and function of miR-138 in LGG.

Methods

Quantitative PCR (qPCR) and public database bioinformatics analysis were performed to determine the miR-138 levels in LGG. MiR-138 overexpression in LGG cells was achieved by miR-138 mimics transfection. Cell proliferation was assessed by CCK8, EdU and colony formation assays. Cell invasion and migration were analyzed by transwell and wound-healing assays. Xenograft model was employed to study the role of miR-138 in LGG growth in vivo. The target of miR-138 was validated by multiple methods, such as luciferase reporter assay, RT-qPCR and Western blot. Bioinformatics analysis was conducted to explore the molecular mechanisms by which miR-138 contributed to LGG progression.

Results

miR-138 was significantly downregulated in LGG tumor tissues and low expression of miR-138 was significantly associated with poor prognosis as well as relapse and metastasis in LGG patients. Functional analysis indicated that ectopic miR-138 expression suppressed LGG cell growth and invasive phenotype in vitro, and inhibited tumor development in vivo. Moreover, miR-138 directly targeted and repressed insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2) by targeting the 3ʹ-UTR of IGF2BP2, inhibiting epithelial to mesenchymal transition (EMT) to attenuate LGG aggressiveness. In addition, we found that elevated IGF2BP2 expression correlates with poor survival of LGG patients.

Conclusion

miR-138 may function as a tumor inhibitor by directly inhibiting IGF2BP2 and suppressing EMT in the progression of LGG.

Modification of miRNA Expression through plant extracts and compounds against breast cancer: Mechanism and translational significance

BACKGROUND

Cancer is hyper-proliferative, multi-factorial and multi-step, heterogeneous group of molecular disorders. It is the second most reported disease after heart diseases. Breast carcinoma is the foremost death causing disease in female population worldwide. Cancer can be controlled by regulating the gene expression. Current therapeutic options are associated with severe side effects and are expensive for the people living in under-developed countries. Plant derived substances have potential application against different diseases like cancer, inflammation and viral infections.

HYPOTHESIS

The mechanism of action of the medicinal plants is largely unknown. Targeting gene network and miRNA using medicinal plants could help in improving the therapeutic options against cancer.

METHODS

The literature from 135 articles was reviewed by using PubMed, google scholar, Science direct to find out the plants and plant-based compounds against breast cancer and also the studies reporting their mechanistic route of action both at coding and noncoding RNA levels.

RESULTS

Natural products act as selective inhibitors of the cancerous cells by targeting oncogenes and tumor suppressor genes or altering miRNA expression. Natural compounds like EGCG from tea, Genistein from fava beans, curcumin from turmeric, DIM found in cruciferous, Resveratrol a polyphenol and Quercetin a flavonoid is found in various plants have been studied for their anticancer activity. The EGCG was found to inhibit proliferative activity by modulating miR-16 and miR-21. Similarly, DIM was found to down regulate miR-92a which results to modulate NFkB and stops cancer development. Another plant-based compound Glyceollins found to upregulate miR-181c and miR-181d having role in tumor suppression. It also found to regulate miR-22, 29b and c, miR-30d, 34a and 195. Quercetin having anti-cancer activity induce the apoptosis through regulating miR-16, 26b, 34a, let-7g, 125a and miR-605 and reduce the miRNA expression like miR-146a/b, 503 and 194 which are involved in metastasis.

CONCLUSION

Targeting miRNA expression using natural plant extracts can have a reverse effect on cell proliferation; turning on and off tumor-inducing and suppressing genes. It can be efficiently adopted as an adjuvant with the conventional form of therapies to increase their efficacy against cancer progression.

MiR-765 functions as a tumour suppressor and eliminates lipids in clear cell renal cell carcinoma by downregulating PLP2

Background

Lipid accumulation has been highlighted in cancer development and progression, but the exact mechanism remains unclear in renal cell carcinoma (RCC). MicroRNAs (miRNAs) have been confirmed to participate in the pathological processes of cancers, including tumour occurrence and inhibition. However, the role and mechanism of miR-765 have not been elucidated in clear cell renal cell carcinoma (ccRCC).

Methods

Using The Cancer Genome Atlas (TCGA) database and qRT-PCR, we investigated differences in miR-765 and proteolipid protein 2 (PLP2) expression, as well as their clinical relevance. To investigate the function of miR-765 and PLP2 in ccRCC, we performed in vitro and in vivo experiments to explore their biological functions in ccRCC.

Findings

In this study, we showed that miR-765 was upregulated in the plasma of ccRCC patients after tumour resection. Consistently, ccRCC tissues had low expression of miR-765 when compared with corresponding non-cancerous tissues. Overexpression of miR-765 suppressed cell proliferation and metastasis in vitro and in vivo. Mechanistic studies demonstrated that PLP2 was a direct target gene of miR-765. PLP2 was highly expressed in ccRCC tissues, and high PLP2 levels were positively correlated with higher tumour stage and grade and poor prognosis. PLP2 expression was negatively correlated with the miR-765 level in patient samples. We further showed that PLP2 restrained the cell metastasis and proliferation induced by miR-765 and reduced the lipid-eliminating effects of miR-765 in renal cancer cells.

Interpretation

Our findings suggest that miR-765 may function as a tumour suppressor and eliminate lipids in clear cell renal cell carcinoma by targeting PLP2.

Funding

This work was funded the grants from the National Natural Scientific Foundation of China (Grant No. 81672528, 81672524, 81602218, 31741032, 81902588).

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

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

MiR-942 regulates the function of breast cancer cell by targeting FOXA2

MicroRNA (MiR)-942 regulates the development of a variety of tumors, however, its function in breast cancer (BCa) has been less reported. Therefore, the present study investigated the regulatory effects of miR-942 on BCa cells. The expression of miR-942 in whole blood samples and BCa cell lines was detected by quantitative real-time (qRT)-PCR. Direct target gene for miR-942 was confirmed by dual-luciferase reporter assay. FOXA2 expression in adjacent tissues was detected by qRT-PCR. The effects of miR-942, or miR-942 with FOXA2, on the cell viability, proliferation, apoptosis, migration and invasion of BCa cells were determined by cell counting kit-8 (CCK-8), colony formation assay, flow cytometry, wound scratch and Transwell, respectively. The levels of N-Cadherin, E-Cadherin and Snail were determined by Western blot. Kaplan-Meier was used to explore the relationship among the expressions of miR-942 and FOXA2 and the prognosis of BCa patients. MiR-942 had high expressed in BCa, while its low expression significantly suppressed the cell viability, proliferation, migration and invasion of BCa, but increased cell apoptosis. Down-regulation of N-Cadherin and Snail and up-regulation of E-Cadherin were also induced by low-expression of miR-942. FOXA2, which was proved as the direct target gene for miR-942 and was low-expressed in BCa, partially reversed the effect of overexpressed miR-942 on promoting cell viability, proliferation, migration and invasion, and suppressed cell apoptosis. A lower survival rate was observed in BCa patients with a high expression of miR-942 and a low expression of FOXA2. MiR-942 promoted the progression of BCa by down-regulating the expression of FOXA2.

MiR-142-3p functions as a tumor suppressor by targeting RAC1/PAK1 pathway in breast cancer

MicroRNA-142-3p (miR-142-3p) was previously investigated in various cancers, whereas, it's role in breast cancer (BC) remains far from understood. In this study, we found that miR-142-3p was markedly decreased both in cell lines and BC tumor tissues. Elevated miR-142-3p expression suppressed growth and metastasis of BC cell lines via gain-of-function assay in vitro and in vivo. Mechanistically, miR-142-3p could regulate the ras-related C3 botulinum toxin substrate 1 (RAC1) expression in protein level, which simultaneously suppressed the epithelial-to-mesenchymal transition related protein levels and the activity of PAK1 phosphorylation, respectively. In addition, rescue experiments revealed RAC1 overexpression could reverse tumor-suppressive role of miR-142-3p. Our results showed miR-142-3p could function as a tumor suppressor via targeting RAC1/PAK1 pathway in BC, suggesting a potent therapeutic target for BC treatment.

Novel and Alternative Targets Against Breast Cancer Stemness to Combat Chemoresistance

Breast cancer stem cells (BCSCs) play a vital role in tumor progression and metastasis. They are heterogeneous and inherently radio- and chemoresistant. They have the ability to self-renew and differentiate into non-BCSCs. These determinants of BCSCs including the plasticity between the mesenchymal and epithelial phenotypes often leads to minimal residual disease (MRD), tumor relapse, and therapy failure. By studying the resistance mechanisms in BCSCs, a combinatorial therapy can be formulated to co-target BCSCs and bulk tumor cells. This review addresses breast cancer stemness and molecular underpinnings of how the cancer stemness can lead to pharmacological resistance. This might occur through rewiring of signaling pathways and modulated expression of various targets that support survival and self-renewal, clonogenicity, and multi-lineage differentiation into heterogeneous bulk tumor cells following chemotherapy. We explore emerging novel and alternative molecular targets against BC stemness and chemoresistance involving survival, drug efflux, metabolism, proliferation, cell migration, invasion, and metastasis. Strategic targeting of such vulnerabilities in BCSCs may overcome the chemoresistance and increase the longevity of the metastatic breast cancer patients.

Identification of a 4-miRNA signature as a potential prognostic biomarker for pancreatic adenocarcinoma

An microRNA (miRNA) signature to predict the clinical outcome of pancreatic adenocarcinoma (PAAD) is still lacking. In the current study, we aimed at identifying and evaluating a prognostic miRNA signature for patients with PAAD. The miRNA expression profile and the clinical information regarding patients with PAAD were recruited from The Cancer Genome Atlas database. Differentially expressed miRNAs were identified between normal and tumor samples. By means of survival analysis, a 4-miRNA signature for predicting patients' with PAAD overall survival (OS) was constructed. Receiver operating characteristic (ROC) analysis was applied to determine the efficiency of survival prediction. Furthermore, the biological function of the predicted miRNAs was evaluated using a bioinformatics approach. Four (hsa-mir-126, hsa-mir-3613, hsa-mir-424, and hsa-mir-4772) out of 17 differentially expressed miRNAs were associated to the OS of patients with PAAD. Moreover, the area under the curve (AUC) of the constructed 4-miRNA signature associated to patients' with PAAD 2-year survival was 0.789. The multivariate Cox's proportional hazards regression model suggested that this 4-miRNA signature was an independent prognostic factor of other clinical parameters in patients with PAAD. Further pathway enrichment analyses revealed that the miRNAs in the 4-miRNA signature might regulate genes that affect focal adhesion, Wnt signaling pathway, and PI3K-Akt signaling pathway. Thus, these findings indicated that the 4-miRNA signature might be an effective independent prognostic biomarker in the prediction of PAAD patients' survival.

Role of DNA methylation regulation of miR-130b expression in human lung cancer using bioinformatics analysis

MicroRNAs (miRNAs) are involved in various crucial biological processes including regulation of cell differentiation, proliferation, and migration, and are closely associated with tumor development. This study aimed to investigate miR-130b expression levels in lung cancer patient tissues. Two Gene Expression Omnibus (GEO) databases, including GSE48414 and GSE74190, and two The Cancer Genome Atlas (TCGA) databases including TCGA LUAD and TCGA LUSC, were accessed to obtain information for differential expression analysis and clinical-pathological correlation analysis. The results showed that miR-130b expression levels were significantly increased in lung cancer compared to normal tissues. Data also demonstrated that confounding factors such as tumor clinical stages and tumor invasion depth markedly affected miR-130b expression levels in cancer patients. A total of 169 target genes modified by miR-130b expression were identified by using 4 online websites for target gene prediction. Further enrichment analysis indicated that these 169 target genes were significantly enriched in several cancer-related biological processes and signaling pathways, including wound healing, cell proliferation, Wnt signaling, Ras signaling, and mTOR signaling. It was also of interest to examine the seven sites on the promoter region of miR-130b encoding gene in lung cancer patients and then compare methylation at these loci with miR-130b expression. The correlation analysis between encoding gene methylation and miR-130b expression in TCGA datasets revealed that decreased methylation in the promoter region was significantly associated with elevated miR-130b expression. This phenomenon was markedly dependent upon smoking history and clinical-pathological features. In conclusion, data indicated alterations in the methylation of DNA promoter region of miR-130b encoding gene were associated with disturbances in miR-130b expression in lung cancer patients suggesting that the DNA methylation process and miR-130b expression may serve as biomarkers for detection of lung cancer.

DNA-Methylation-Caused Downregulation of miR-30 Contributes to the High Expression of XPO1 and the Aggressive Growth of Tumors in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma is one of the most aggressive cancers, with high mortality in the United States. One of the important signal transduction proteins involved in the regulation of pancreatic cancer's aggressive progression is the nuclear export protein (XPO1). High expression of XPO1 has been found in pancreatic, lung, breast and other cancers and lymphomas with a poor prognosis of patients with tumors and high proliferative activity of cancer cells. Because XPO1 exports multiple tumor suppressor proteins simultaneously from the nucleus, the inhibition of XPO1 may retain multiple tumor suppressors in the nucleus, resulting in the suppression of cell proliferation and the induction of apoptosis in tumors. In this study, we found that the high expression of XPO1 in pancreatic cancer cells could be, in part, due to the methylation of the miR-30 gene, leading to the low expression level of the miR-30 family. By co-transfection of the XPO1 3'-UTR-Luc target vector with miR-30 mimic, we found that XPO1 is a direct target of the miR-30 family. We also observed that the enforced expression of the miR-30 family inhibited the expression of XPO1, resulting in the suppression of pancreatic cancer growth both in vitro and in vivo. These findings could help to design a novel therapeutic strategy for the treatment of pancreatic cancer by introducing miR-30 into cancer cells.

miR-665 expression predicts poor survival and promotes tumor metastasis by targeting NR4A3 in breast cancer

Cancer metastasis is the main cause of death in breast cancer (BC) patients. Therefore, prediction and treatment of metastasis is critical for enhancing the survival of BC patients. In this study, we aimed to identify biomarkers that can predict metastasis of BC and elucidate the underlying mechanism of the functional involvement of such markers in metastasis. miRNA expression profile was analyzed using a custom microarray system in 422 BC tissues. The relationship between the upregulated miR-665, metastasis and survival of BC was analyzed and verified in another set of 161 BC samples. The biological function of miR-665 in BC carcinogenesis was explored with in vitro and in vivo methods. The target gene of miR-665 and its signaling cascade were also analyzed. There are 399 differentially expressed miRNAs between BC and noncancerous tissues, of which miR-665 is the most upregulated miRNA in the BC tissues compared with non-tumor breast tissues (P < 0.001). The expression of miR-665 predicts metastasis and poor survival in 422 BC patients, which is verified in another 161 BC patients and 2323 BC cases from online databases. Ectopic miR-665 expression promotes epithelial–mesenchymal transition (EMT), proliferation, migration and invasion of BC cells, and increases tumor growth and metastasis of BC in mice. Bioinformatics, luciferase assay and other methods showed that nuclear receptor subfamily 4 group A member 3 (NR4A3) is a target of miR-665 in BC. Mechanistically, we demonstrated that miR-665 promotes EMT, invasion and metastasis of BC via inhibiting NR4A3 to activate MAPK/ERK kinase (MEK) signaling pathway. Our study demonstrates that miR-665 upregulation is associated with metastasis and poor survival in BC patients, and mechanistically, miR-665 enhances progression of BC via NR4A3/MEK signaling pathway. This study provides a new potential prognostic biomarker and therapeutic target for BC patients.

Interactive functions of microRNAs in the miR-23a-27a-24-2 cluster and the potential for targeted therapy in cancer

MicroRNAs (miRNAs) are small noncoding RNAs about 19-22 nucleotides in length. Growing evidence has reported the significant role of miRNAs in various cancer-associated biological processes, such as proliferation, differentiation, apoptosis, metabolism, invasion, metastasis, and drug resistance. However, most studies focus on the targets of some individual miRNAs; the interactive and global functions of diverse miRNAs are still unclear and the phenomenon of the gathering of miRNAs in clusters has always been ignored. On the other hand, the fact that a single miRNA may regulate many genes and that numerous mRNAs are regulated by the same miRNA also makes it imperative to further study the cooperating characteristics of miRNAs in cancer. MiR-23a-27a-24-2 is located in the human chromosome 9q22, forming three mature miRNAs: miR-23a, miR27a, and miR-24, which are expressed abnormally in many malignant tumors. This review aims to summarize the interactive functions of miRNAs in miR-23a-27a-24-2 clusters in cancer from the perspectives of the regulation network, tumor microenvironment, and targeted therapy.