The role of miR-145 in stem cell characteristics of human laryngeal squamous cell carcinoma Hep-2 cells

An insight into the associations between microRNA expression and mitochondrial functions in cancer cell and cancer stem cell

The self-renew ability of cancer stem cells (CSCs) continues to challenge our determination for accomplishing cancer therapy breakthrough. Ineffectiveness of current cancer therapies to eradicate CSCs has contributed to chemoresistance and tumor recurrence. Yet, the discoveries of highly effective therapies have not been thoroughly developed. Further insights into cancer metabolomics and gene-regulated mechanisms of mitochondria in CSCs can expedite the development of novel anticancer drugs. In cancer cells, the metabolism is reprogrammed from oxidative phosphorylation (OXPHOS) to glycolysis. This alteration allows the cancer cell to receive continuous energy supplies and avoid apoptosis. The pyruvate obtained from glycolysis produces acetyl-coenzyme A (Acetyl-CoA) via oxidative decarboxylation and enters the tricarboxylic acid cycle for adenosine triphosphate generation. Mitochondrial calcium ion (Ca²⁺) uptake is responsible for mitochondrial physiology regulation, and reduced uptake of Ca²⁺  inhibits apoptosis and enhances cell survival in cancer. There have been many discoveries of mitochondria-associated microRNAs (miRNAs) stimulating the metabolic alterations in mitochondria via gene regulation which promote cancer cell survival. These miRNAs are also found in CSCs where they regulate genes and activate different mechanisms to destroy the mitochondria and enhance CSCs survival. By targeting the miRNAs that induced mitochondrial destruction, the mitochondrial functions can be restored; thus, it triggers CSCs apoptosis and completely eliminates the CSCs. In general, this review article aims to address the associations between miRNAs with mitochondrial activities in cancer cells and cancer stem cells that support cancer cell survival and self-renewal.

Diagnostic and Prognostic Value of microRNAs in Patients with Laryngeal Cancer: A Systematic Review

Laryngeal squamous cell cancer (LSCC) is one of the most common malignant tumors of the head and neck region, with a poor survival rate (5-year overall survival 50-80%) as a consequence of an advanced-stage diagnosis and high recurrence rate. Tobacco smoking and alcohol abuse are the main risk factors of LSCC development. An early diagnosis of LSCC, a prompt detection of recurrence and a more precise monitoring of the efficacy of different treatment modalities are currently needed to reduce the mortality. Therefore, the identification of effective diagnostic and prognostic biomarkers for LSCC is crucial to guide disease management and improve clinical outcomes. In the past years, a dysregulated expression of small non-coding RNAs, including microRNAs (miRNAs), has been reported in many human cancers, including LSCC, and many miRNAs have been explored for their diagnostic and prognostic potential and proposed as biomarkers. We searched electronic databases for original papers that were focused on miRNAs and LSCC, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. According to the outcome, 566 articles were initially screened, of which 177 studies were selected and included in the analysis. In this systematic review, we provide an overview of the current literature on the function and the potential diagnostic and prognostic role of tissue and circulating miRNAs in LSCC.

Potentials of lncRNA-miRNA-mRNA networks as biomarkers for laryngeal squamous cell carcinoma

Chemoresistance, radioresistance, and facile spreading of laryngeal squamous cell carcinoma (LSCC) make the practically clinical treatment invalid. Such dismal outcome mainly originates from the lack of effective biomarkers which are highly desirable to understand the pathogenesis of LSCC, and strives to find promising novel biomarkers to improve early screening, effective treatment, and prognosis evaluation in LSCC. Recently, long non-coding RNAs (lncRNAs), a kind of non-coding RNAs longer than 200 nucleotides, can participate in the process of tumorigenesis and progression through many regulatory modalities, such as epigenetic transcriptional regulation and post-transcriptional regulation. Meanwhile, microRNAs (miRNAs, miRs), essentially involved in the post-transcriptional regulation of gene expression, are aberrantly expressed in cancer-related genomic regions or susceptible sites. An increasing number of studies have shown that lncRNAs are important regulators of miRNAs expression in LSCC, and that miRNAs can also target to regulate the expression of lncRNAs, and they can target to regulate downstream messenger RNAs (mRNAs) transcriptionally or post-transcriptionally, thereby affecting various physiopathological processes of LSCC. Complex cross-regulatory networks existing among lncRNAs, miRNAs, and mRNAs can regulate the tumorigenesis and development of LSCC. Such networks may become promising biomarkers and potential therapeutic targets in the research field of LSCC. In this review, we mainly summarize the latest research progress on the regulatory relationships among lncRNAs, miRNAs, and downstream mRNAs, and highlight the potential applications of lncRNA-miRNA-mRNA regulatory networks as biomarkers for the early diagnosis, epithelial-mesenchymal transition (EMT) process, chemoresistance, radioresistance, and prognosis of LSCC, aiming to provide important clues for understanding the pathogenesis of LSCC and developing new diagnostic and therapeutic strategies.

Reciprocal interplays between MicroRNAs and pluripotency transcription factors in dictating stemness features in human cancers

The interplay between microRNAs (miRNAs) and pluripotency transcription factors (TFs) orchestrates the acquisition of cancer stem cell (CSC) features during the course of malignant transformation, rendering them essential cancer cell dependencies and therapeutic vulnerabilities. In this review, we discuss emerging themes in tumor heterogeneity, including the clonal evolution and the CSC models and their implications in resistance to cancer therapies, and then provide thorough coverage on the roles played by key TFs in maintaining normal and malignant stem cell pluripotency and plasticity. In addition, we discuss the reciprocal interactions between miRNAs and MYC, OCT4, NANOG, SOX2, and KLF4 pluripotency TFs and their contributions to tumorigenesis. We provide our view on the potential to interfere with key miRNA-TF networks through the use of RNA-based therapeutics as single agents or in combination with other therapeutic strategies, to abrogate the CSC state and render tumor cells more responsive to standard and targeted therapies.

Global microRNA expression profile in laryngeal carcinoma unveils new prognostic biomarkers and novel insights into field cancerization

Laryngeal carcinoma is still a worldwide burden that has shown no significant improvement during the last few decades regarding definitive treatment strategies. The lack of suitable biomarkers for personalized treatment protocols and delineating field cancerization prevents further progress in clinical outcomes. In the light of this perspective, MicroRNAs could be promising biomarkers both in terms of diagnostic and prognostic value. The aim of this prospective study is to find strong prognostic microRNA biomarkers for advanced laryngeal carcinoma and molecular signatures of field cancerization. Sixty patients were enrolled and four samples were collected from each patient: tumor surface and depth, peritumor normal mucosa, and control distant laryngeal mucosa. Initially, a global microRNA profile was conducted in twelve patients from the whole cohort and subsequently, we validated a selected group of 12 microRNAs with RT-qPCR. The follow-up period was 24 months (SD ± 13 months). Microarray expression profile revealed 59 dysregulated microRNAs. The validated expression levels of miR-93-5p (χ²(2) = 4.68, log-rank p = 0.03), miR-144-3p (χ²(2) = 4.53, log-rank p = 0.03) and miR-210-3p (χ²(2) = 4.53, log-rank p = 0.03) in tumor samples exhibited strong association with recurrence-free survival as higher expression levels of these genes predict worse outcome. Tumor suppressor genes miR-144-3p (mean rank 1.58 vs 2.14 vs 2.29, p = 0.000) and miR-145-5p (mean rank 1.57 vs 2.15 vs 2.28, p = 0.000) were significantly dysregulated in peritumor mucosa with a pattern of expression consistent with paired tumor samples thus revealing a signature of field cancerization in laryngeal carcinoma. Additionally, miR-1260b, miR-21-3p, miR-31-3p and miR-31-5p were strongly associated with tumor grade. Our study reports the first global microRNA profile specifically in advanced laryngeal carcinoma that includes survival analysis and investigates the molecular signature of field cancerization. We report two strong biomarkers of field cancerization and three predictors for recurrence in advance stage laryngeal cancer.

Epithelial-to-Mesenchymal Transition in Metastasis: Focus on Laryngeal Carcinoma

In epithelial neoplasms, such as laryngeal carcinoma, the survival indexes deteriorate abruptly when the tumor becomes metastatic. A molecular phenomenon that normally appears during embryogenesis, epithelial-to-mesenchymal transition (EMT), is reactivated at the initial stage of metastasis when tumor cells invade the adjacent stroma. The hallmarks of this phenomenon are the abolishment of the epithelial and acquisition of mesenchymal traits by tumor cells which enhance their migratory capacity. EMT signaling is mediated by complex molecular pathways that regulate the expression of crucial molecules contributing to the tumor’s metastatic potential. Effectors of EMT include loss of adhesion, cytoskeleton remodeling, evasion of apoptosis and immune surveillance, upregulation of metalloproteinases, neovascularization, acquisition of stem-cell properties, and the activation of tumor stroma. However, the current approach to EMT involves a holistic model that incorporates the acquisition of potentials beyond mesenchymal transition. As EMT is inevitably associated with a reverse mesenchymal-to-epithelial transition (MET), a model of partial EMT is currently accepted, signifying the cell plasticity associated with invasion and metastasis. In this review, we identify the cumulative evidence which suggests that various aspects of EMT theory apply to laryngeal carcinoma, a tumor of significant morbidity and mortality, introducing novel molecular targets with prognostic and therapeutic potential.

MicroRNAs regulating SOX2 in cancer progression and therapy response

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

miR-145-5p as a predictive biomarker for breast cancer stemness by computational clinical investigation

BACKGROUND

Breast tumors enriched with breast cancer stem cells (BCSCs), play a crucial role in metastasis and tumor relapse. Hence, targeting BCSCs may lead to efficacious breast cancer therapy. BCSCs have a unique expression of stemness markers, including Nanog, POU5F1, SOX2, and CD44, which play a vital role in cancer stem cell properties. However, the regulation of microRNAs (miRNAs)-mediated cancer stem cell marker expressions is largely unclear.

METHODS

MIENTURNET was used to predict miRNA-target interactions. miR-TV, UALCAN and GEPIA databases were used to analyze the expression of miR-145-5p and SOX2. Survival analysis was obtained by cBioportal, KM plotter and Breast Cancer Gene-Expression Miner. RNAComposer was used to perform miRNA-mRNA duplex prediction. In vitro mRNA and miRNA analysis was performed by qRT-PCR.

RESULTS

It was observed that miR-145-5p was the common miRNA targeting stemness markers. miR-145-5p expression was found to be lower in breast cancer patients compared to healthy subjects. Based on survival analysis, low expression of miR-145-5p and high expression of SOX2 led to a poor overall survival rate in breast cancer patients. Pathway enrichment analysis indicated that SOX2 was highly enriched with transcription factors. Moreover, SOX2 expression level was also upregulated in axillary metastatic lymph nodules. Further, in vitro ectopic expression of miR-145-5p by its mimic downregulated the SOX2 expression compared to the control mimic. Overall, SOX2 was a direct target for miR-145-5p as per the binding and minimal-free energy.

CONCLUSIONS

In this study, miR-145-5p targeting SOX2 was identified as a potential predictive biomarker for breast cancer stemness.

Potential prognostic markers and significant lncRNA-mRNA co-expression pairs in laryngeal squamous cell carcinoma

lncRNA-mRNA co-expression pairs and prognostic markers related to the development of laryngeal squamous cell carcinoma (LSCC) were investigated. The lncRNA and mRNA expression data of LSCC in GSE84957 and RNA-seq data of 112 LSCC samples from TCGA database were used. Differentially expressed genes (DEGs) and lncRNAs (DE-lncRNAs) between LSCC and para-cancer tissues were identified. Co-expression analysis of DEGs and DE-lncRNA was conducted. Protein-protein interaction network for co-expressed DEGs of top 25 DE-lncRNA was constructed, followed by survival analysis for key nodes in co-expression network. Finally, expressions of several DE-lncRNAs and DEGs were verified using qRT-PCR. The lncRNA-mRNA network showed that ANKRD20A5P, C21orf15, CYP4F35P, LOC_I2_011146, XLOC_006053, XLOC_I2_003881, and LOC100506027 were highlighted in network. Some DEGs, including FUT7, PADI1, PPL, ARHGAP40, MUC21, and CEACAM1, were co-expressed with above lncRNAs. Survival analysis showed that PLOD1, GLT25D1, and KIF22 were significantly associated with prognosis. qRT-PCR results showed that the expressions of MUC21, CEACAM1, FUT7, PADI1, PPL, ARHGAP40, ANKRD20A5P, C21orf15, CYP4F35P, XLOC_I2_003881, LOC_I2_011146, and XLOC_006053 were downregulated, whereas the expression of LOC100506027 was upregulated in LSCC tissues. PLOD1, GLT25D1, and KIF22 may be potential prognostic markers in the development of LSCC. C21orf15-MUC21/CEACAM1/FUT7/PADI1/PPL/ARHGAP40 are potential lncRNA-mRNA pairs that play significant roles in the development of LSCC.

Current research advances in microRNA-mediated regulation of Krüppel-like factor 4 in cancer: a narrative review

Objective

The purpose of this study was to investigate the miRNAs and related mechanisms that regulates KLF4 in different cancers. Furthermore, we summarized the potential targets of miRNAs regulating the KLF4 pathway in cancer research.

Background

MiRNAs are single-stranded, endogenous non-coding small RNAs, some of which are related to human cancers. miRNAs carry out post-transcriptional gene regulation through translation inhibition and degradation of target messenger RNAs (mRNAs) via complementarily pairing with their 3' untranslated regions. KLF4 is an important transcription factor with complex involvement in cancer. Increasing evidence shows that miRNAs are dysregulated in cancer and can regulate cancer-related signaling pathways, thereby affecting tumor progression.

Methods

Systematic scientific literature searches were undertaken on PubMed using the following terms: "miRNAs and KLF4", "KLF4 and cancer", "miRNAs and cancer", and "miRNAs, KLF4 and cancer". Relevant papers were retrieved and further results were found by reviewing related papers and the references of the retrieved papers. We then conducted a narrative overview of the literature to summarize the results of the papers.

Conclusions

The role of KLF4 in cancer varies in a context-dependent manner. KLF4-regulating miRNAs in different tumors include miR-124, miR-9-5p, miR-10b, miR-18a, miR-25-3p, miR-10b, miR-92a, miR-103, miR-155, miR-135b-5p, miR-32-5p, miR-148-3p, miR-152-3p, miR-10b, miR-25, miR-3120-5p, miR-7, miR-1233-3p, miR-10b, miR-145, miR-139-5p, miR-16, miR-152, miR-375, and miR-145.

MicroRNA-145 transcriptionally regulates Semaphorin 3A expression in prostate cancer cells

Prostate cancer (PCa) is one of the most prevalent cancer types among males. Differential expression of microRNAs is associated with various cancers including PCa. Although mature microRNAs are preferentially located in the cytoplasm, several studies identified mature human microRNAs in purified nuclei and miR-145 has been found to be predominantly expressed in the nuclei of benign tissues compared to tumor lesions. However, the nuclear functions of miR-145 are yet limited. Here, we aimed at investigating the inductive role of miR-145 on the expression of Semaphorin 3A (SEMA3A) in PCa cell lines. To study the regulatory potential of miR-145 in the transcriptional level in PCa, we overexpressed miR-145 in PC3 and DU145 cells, and confirmed its upregulation by quantitative-real-time-PCR. Then we investigated the tumor suppressor potential of miR-145 upon inducing SEMA3A expression using cell viability assay, western blot analysis, Chromatin Immunoprecipitation assay and luciferase reporter assay. Our results revealed that p53, miR-145, and SEMA3A expressions are significantly downregulated in PC3 and DU145 cells compared to nontumorigenic prostate epithelial PNT1a cells. miR-145 overexpression in PCa cells induced the expression of SEMA3A at both messenger RNA and protein levels. Furthermore, increased miR-145 expression enriched RNA Pol-II antibody on the promoter of SEMA3A and induced luciferase activity controlled by SEMA3A promoter. In this study, we showed that the functions of miR-145 are not limited to gene silencing, and found that it may lead to changes in gene expression in the transcriptional level.

MicroRNA-145 targets in cancer and the cardiovascular system: evidence for common signaling pathways

miRNAs are small regulatory RNAs which govern gene expression post-transcriptionally by primarily binding to the 3'-UTR of mRNA target genes. miR-145 is a well-studied miRNA that has been implicated in controlling a range of biological processes. miR-145 is expressed in a variety of tissues and cell types and acts as a tumor-suppressor by regulating target gene signaling pathways involved in different aspects of tumor growth and progression. There is also strong evidence that highlights the important functions of miR-145 in the cardiovascular system. Here, we review the mechanisms of miR-145 in tumorigenesis and cancer progression and compare and contrast with the roles of miR-145 in cardiovascular development and disease. We discuss the important targets of miR-145 in cancer and their possible link to the cardiovascular system.

The P53/microRNA network: A potential tumor suppressor with a role in anticancer therapy

MicroRNAs (miRNAs) are endogenous and small non-coding RNAs that have been identified as mediators of tumor suppression as well as stress responses mediated by p53 suppressors. MiRNAs may act as tumor suppressors under certain conditions. MiRNAs regulated by p53 may control the expression of processes such as cell cycle progression, cell survival, and angiogenesis. P53 activity and expression are also controlled by miRNA; consequently alterations in the p53-miRNA network may be essential for tumor initiation and progression. Future studies on the p53-miRNA network presumably would find it helpful in diagnostic and therapeutic approaches or as tools for various cancers.

Dysregulated microRNAs in laryngeal cancer: a comprehensive meta-analysis using a robust rank aggregation approach

We need a reasonable method of compiling data from different studies regarding the expression of microRNA (miRNA) in laryngeal squamous cell carcinoma (LSCC). The robust rank aggregation method was used to integrate the rank lists of miRNAs from 11 studies. The enrichment analysis was performed on target genes of meta-signature miRNAs. The Cancer Genome Atlas database was used to confirm the results of meta-analysis. Three meta-signature miRNAs (miR-21-5p, miR-196a-5p and miR-145-5p) were obtained. All three miRNAs could be prognostic for LSCC. The enrichment analysis showed that these miRNAs were associated significantly with multiple cancer-related signaling pathways. The robust rank aggregation approach is an effective way to identify important miRNAs from different studies. All identified miRNAs could be candidates for LSCC diagnostic and prognostic biomarkers.

miR-331-3p suppresses cell invasion and migration in colorectal carcinoma by directly targeting NRP2

Colorectal carcinoma (CRC) is a common tumor of the digestive system with poor prognosis. Studies have shown that aberrant microRNA (miRNA) expression can affect CRC progression by regulating target genes. In the present study, we investigated the functional roles and potential mechanisms of miR-331-3p in CRC. The expression of miR-331-3p and neuropilin-2 (NRP2) in CRC was detected by RT-qPCR. Then, Transwell assays were conducted to investigate the influence of miR-331-3p on CRC cell invasion and migration abilities. Luciferase reporter assays were performed to determine the target gene of miR-331-3p. It was found that miR-331-3p expression was notably declined in CRC and inversely correlated with the NRP2 expression. miR-331-3p upregulation significantly inhibited CRC cell invasion and migration. Additionally, western blot analysis demonstrated that miR-331-3p restoration evidently suppressed CRC cell EMT. Moreover, NRP2 was conformed to be a novel target of miR-331-3p and knockdown of NRP2 partially inversed the effects of the miR-331-3p inhibitor on cell invasion and migration. These results suggested that miR-331-3p exerted tumor suppressive roles in CRC by targeting NRP2 and miR-331-3p/NRP2 may serve as a potential therapy for CRC.

lncRNA TMEM51-AS1 and RUSC1-AS1 function as ceRNAs for induction of laryngeal squamous cell carcinoma and prediction of prognosis

BACKGROUND

Long non-coding RNAs (lncRNAs) can function as competing endogenous RNAs (ceRNAs) to interact with miRNAs to regulate target genes and promote cancer initiation and progression. The expression of lncRNAs and miRNAs can be epigenetically regulated. The goal of this study was to construct an lncRNA-miRNA-mRNA ceRNA network in laryngeal squamous cell carcinoma (LSCC) and reveal their methylation patterns, which was not investigated previously.

METHODS

Microarray datasets available from the Gene Expression Omnibus database were used to identify differentially expressed lncRNAs (DELs), miRNAs (DEMs), and genes (DEGs) between LSCC and controls, which were then overlapped with differentially methylated regions (DMRs). The ceRNA network was established by screening the interaction relationships between miRNAs and lncRNAs/mRNAs by corresponding databases. TCGA database was used to identify prognostic biomarkers.

RESULTS

Five DELs (downregulated: TMEM51-AS1, SND1-IT1; upregulated: HCP5, RUSC1-AS1, LINC00324) and no DEMs were overlapped with the DMRs, but only a negative relationship occurred in the expression and methylation level of TMEM51-AS1. Five DELs could interact with 11 DEMs to regulate 242 DEGs, which was used to construct the ceRNA network, including TMEM51-AS1-miR-106b-SNX21/ TRAPPC10, LINC00324/RUSC1-AS1-miR-16-SPRY4/MICAL2/ SLC39A14, RUSC1-AS1-miR-10-SCG5 and RUSC1-AS1-miR-7-ZFP1 ceRNAs axes. Univariate Cox regression analysis showed RUSC1-AS1 and SNX21 were associated with overall survival (OS); LINC00324, miR-7 and ZFP1 correlated with recurrence-free survival (RFS); miR-16, miR-10, SCG5, SPRY4, MICAL2 and SLC39A14 were both OS and RFS-related. Furthermore, TRAPPC10 and SLC39A14 were identified as independent OS prognostic factors by multivariate Cox regression analysis.

CONCLUSION

DNA methylation-mediated TMEM51-AS1 and non-methylation-mediated RUSC1-AS1 may function as ceRNAs for induction of LSCC. They and their ceRNA axis genes (particularly TMEM51-AS1-miR-106b-TRAPPC10; RUSC1-AS1-miR-16-SLC39A14) may be potentially important prognostic biomarkers for LSCC.

Expression and clinical significance of miRNA-145 and miRNA-218 in laryngeal cancer

Expression of miRNA-145 and miRNA-218 in serum of patients with laryngeal cancer and the relationship between them and the clinicopathological parameters and prognosis were investigated. The clinical medical records of 132 patients with laryngeal cancer, who were admitted to Guangdong Second Provincial General Hospital from February 2009 to March 2014, were retrospectively analyzed and comprised the study group. The data of physical examinations of 56 healthy volunteers who took physical examinations in the same hospital comprised the control group. RT-qPCR was used to detect the expression levels of miRNA-145 and miRNA-218 in serum of the patients in the two groups. According to the relative expression levels of miRNA-145 and miRNA-218 in serum of the patients in the study group on the day when they left hospital, the study group was divided into the high expression group (n=73 patients) and the low expression group (n=59 patients). The patients received a 48-month follow-up visit and their survival condition was recorded and the Kaplan-Meier was used to carry out the survival analysis. The expression levels of miRNA-145 and miRNA-218 in serum of the patients in the study group were lower than those in the control group (P<0.05). The median survival time of the patients in the high expression group was 30 months while the median survival time of the patients in the low expression group was 26 months. The expression levels of miRNA-145 and miRNA-218 in serum of patients with laryngeal cancer decreased, the higher the expression levels of miRNA-145 and miRNA-218 in serum of patients with laryngeal cancer were, the better the prognosis was. miRNA-145 and miRNA-218 were used as indicators of assessing the prognosis of patients with laryngeal cancer.

miR-145-5p Suppresses Breast Cancer Progression by Inhibiting SOX2

BACKGROUND

In this study, we aimed to investigate the expression and clinical significance of miR-145-5p and its tumor-suppressive effect in breast cancer patients.

METHODS

We used luciferase reporter assay, real-time quantitative reverse transcription polymerase chain reaction and Western blot to identify sex-determining region Y-box2 (SOX2) as the target gene of miR-145-5p. Their expression levels in breast cancer tissues (n = 122) were detected by real-time quantitative polymerase chain reaction. We also applied 3-(4,5-dimethyl- 2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay and flow cytometry to reveal the effect of miR-145-5p on proliferation in breast cancer.

RESULTS

miR-145-5p expression is downregulated in breast cancer tissues and negatively correlated with SOX2 expression. Decreased miR-145-5p expression was significantly associated with larger tumor size, distal metastasis, higher Ki67 expression level, and shorter overall survival. miR-145-5p inhibits breast cancer cell proliferation via targeting SOX2, and multivariate regression showed that both miR-145-5p and SOX2 were unfavorable prognostic factors.

CONCLUSIONS

miR-145-5p played a suppressive role in the proliferation of breast cancer cells by targeting SOX2, and miR-145-5p is a putative biomarker for risk assessment in patients with breast cancer.

Promoter Methylation-Regulated miR-145-5p Inhibits Laryngeal Squamous Cell Carcinoma Progression by Targeting FSCN1

Laryngeal squamous cell carcinoma (LSCC) is a common form of head and neck cancer with poor prognosis. However, the mechanism underlying the pathogenesis of LSCC remains unclear. Here, we demonstrated increased expression of fascin actin-bundling protein 1 (FSCN1) and decreased expression of microRNA-145-5p (miR-145-5p) in a clinical cohort of LSCC. Luciferase assay revealed that miR-145-5p is a negative regulator of FSCN1. Importantly, low miR-145-5p expression was correlated with TNM (tumor, node, metastasis) status and metastasis. Moreover, cases with low miR-145-5p/high FSCN1 expression showed poor prognosis, and these characteristics together served as independent prognostic indicators of survival. Gain- and loss-of-function studies showed that miR-145-5p overexpression or FSCN1 knockdown inhibited LSCC migration, invasion, and growth by suppressing the epithelial-mesenchymal transition along with inducing cell-cycle arrest and apoptosis. Additionally, hypermethylation of the miR-145-5p promoter suggested that repression of miR-145-5p arises through epigenetic inactivation. LSCC tumor growth in vivo could be inhibited by using miR-145-5p agomir or FSCN1 small interfering RNA (siRNA), which highlights the potential for clinical translation. Collectively, our findings indicate that miR-145-5p plays critical roles in inhibiting the progression of LSCC by suppressing FSCN1. Both miR-145-5p and FSCN1 are important potential prognostic markers and therapeutic targets for LSCC.

Long non-coding RNA AFAP1-AS1/miR-320a/RBPJ axis regulates laryngeal carcinoma cell stemness and chemoresistance

AFAP1-AS1 is a long non-coding RNA that is associated with tumorigenesis and poor prognosis in a variety of cancers. We have been suggested that AFAP1-AS1 increases tumorigenesis in laryngeal carcinoma specifically by enhancing stemness and chemoresistance. We assessed AFAP1-AS1 expression in human laryngeal specimens, paired adjacent normal tissues and human HEp-2 cells. Indeed, we found not only that AFAP1-AS1 was up-regulated in laryngeal carcinoma specimens and cells, but also that stemness-associated genes were overexpressed. Silencing of AFAP1-AS1 promoted HEp-2 cell chemoresistance under cisplatin treatment. Expression of AFAP1-AS1 was increased in drug-resistant Hep-2 cells. We then probed the mechanism of AFAP1-AS1 activity and determined that miR-320a was a potential molecular target of AFAP1-AS1. Luciferase reporter and qRT-PCR assays of AFAP1-AS1 and miR-320a levels in human specimens and cell cultures indicated that AFAP1-AS1 negatively regulates miR-320a. To discover the molecular mechanism of miR-320a, we again used the DIANA Tools algorithm to predict its genetic target, RBPJ. After cloning the 3'-untranslated regions (3'-UTR) of RBPJ into a luciferase reporter, we determined that miR-320a did in fact reduce RBPJ mRNA and protein levels. Ultimately, we determined that AFAP1-AS1 increases RBPJ expression by negatively regulating miR-320a and RBPJ overexpression rescues stemness and chemoresistance inhibited by AFAP1-AS1 silencing. Taken together, these results suggest that AFAP1-AS1 can serve as a prognostic biomarker in laryngeal carcinoma and that miR-320a has the potential to improve standard therapeutic approaches to the disease, especially for cases in which cancer cell stemness and drug resistance present significant barriers to effective treatment.

MiRNA-mRNA crosstalk in laryngeal squamous cell carcinoma based on the TCGA database

BACKGROUND

The functional characterization of non-coding microRNAs (miRNAs) has been shown to be associated with the pathophysiology of the disease, but it is still a challenging task to elucidate the pathogenesis of microRNAs and disease. In addition, the understanding of the role of miRNAs in the development of LSCC still needs further exploration.

MATERIALS AND METHODS

In this study, to identify miRNAs that play a key role in LSCC, we analyzed miRNA and mRNA sequence data from 162 LSCC samples from the TCGA database, and screened specific miRNAs and mRNAs by differential gene expression analysis. And then, construct a differentially expressed miRNAs and mRNAs interaction network.

RESULTS

In our investigation, 23 miRNAs (P < 0.01, log2FoldChange > 2) and 331 mRNAs (P < 0.01, log2FoldChange > 4) were identified differentially expressed in LSCC and reduced the number of loosely linked miRNAs and mRNAs according to appropriate thresholds. Finally, 13 miRNAs and 35 mRNAs were enriched in a network.

CONCLUSIONS

Our study provides the most comprehensive information on the expression of miRNAs in LSCC and identifies the known oncogenic miRNAs (such as miR-163a), as well as aberrant expression of novel miRNAs involved in cell regulation and metabolic defects that occur during development of LSCC.

Analysis of gene expression profiling variations induced by hsa‑miR‑145‑5p‑overexpression in laryngeal squamous cell carcinoma cell line Tu‑177

The present study aimed to investigate the variations of the gene network and biological functions induced by hsa‑miR‑145‑5p in the laryngeal squamous cell carcinoma (LSCC) cell line Tu‑177. A hsa‑miR‑145‑5p‑overexpressed Tu‑177 cell model was established, and the gene expression microarray data of miR‑145‑5p‑overexpressed cells and negative control (NC) cells were analyzed. The differentially expressed genes (DEGs) between two groups were identified, and their potential functions were predicted by functional enrichment analysis. Furthermore, the targets of miR‑145‑5p were identified from the DEGs, and their potential functions and protein‑protein interactions (PPIs) were analyzed. The mRNA expressions of acetyl‑CoA carboxylase β (ACACB), fibroblast growth factor receptor 1 (FGFR1), protein phosphatase 3 catalytic subunit a (PPP3CA) and spleen associated tyrosine kinase (SYK), were analyzed via quantitative polymerase chain reaction. A total of 1,501 upregulated and 887 downregulated genes were identified in the hsa‑miR‑145‑5p‑overexpressed Tu‑177 cells, compared with the NC cells. Of these DEGs, 164 upregulated and 221 downregulated genes were predicted to be targeted by hsa‑miR‑145‑5p. The upregulated target genes were primarily associated with functions of immunity, whereas the downregulated target genes were significantly enriched in the p53 signaling pathway. In the PPI network consisting of 267 target genes, the upregulated ACACB had the greatest degree and interacted with downregulated genes including PPP3CA and SYK, in addition to upregulated genes, including FGFR1. The mRNA expressions of ACACB and FGFR1were markedly enhanced in miR‑145‑5p‑overexpressed Tu‑177 cells, whereas overexpressing miR‑145‑5p significantly reduced mRNA expression of PPP3CA and SYK. hsa‑miR‑145‑5p may exhibit an anticancer role in LSCC via regulating multiple cell processes, including cell proliferation and invasion, fatty acid metabolism, immunity and p53 signaling pathway. These findings provide novel information for the future investigation of miR‑145‑5p functions in LSCC.

Ribonucleic acid interference knockdown of IL-6 enhances the efficacy of cisplatin in laryngeal cancer stem cells by down-regulating the IL-6/STAT3/HIF1 pathway

Background

Cisplatin has been used in the treatment of many cancers, including laryngeal cancer; however, its efficacy can be reduced due to the development of drug resistance. This study aimed to investigate whether interleukin-6 (IL-6) knockdown may enhance the efficacy of cisplatin in laryngeal cancer stem cells (CSC) and the potential involvement of the signal transducer and activator of transcription 3 (STAT3) and hypoxia-inducible factor 1 (HIF1) in this effect.

Methods

The ALDH+ and CD44+ CSC in Hep2 human laryngeal squamous cancer cells were identified by the fluorescence-activated cell sorting technique. IL-6, STAT3 and HIF1 mRNA and protein expressions were examined with quantitative real-time polymerase chain reaction and Western blot, respectively. Cell proliferation was measured by MTT assay. Tumorigenicity was measured by a colony formation assay and invasion was determined by a cell invasion assay. Apoptotic cells were counted by flow cytometry. Immunohistochemistry was performed to detect immunoreactive IL-6, STAT3 and HIF1 cells in xenografts.

Results

The mRNA and protein levels of IL-6, STAT3 and HIF1 were significantly increased in Hep2-CSC as compared with those from Hep2 cells. Application of siRNA-IL-6 to knockdown IL-6 resulted in significantly decreased IL-6, STAT3 and HIF1 mRNA and protein levels. IL-6 knockdown reduced cell proliferation, tumorigenicity and invasion and increased apoptosis within CSC. Enhanced degrees of suppression in these parameters were observed when IL-6 knockdown was combined with cisplatin in these CSC. Results from the xenograft study showed that the combination of IL-6 knockdown and cisplatin further inhibited the growth of xenografts as compared with that obtained in the cisplatin-injected group alone. Immunoreactive IL-6, STAT3 and HIF1 cell numbers were markedly reduced in IL-6 knockdown tumor tissues. IL-6, STAT3 and HIF1 immunoreactive cell counts were further reduced in tissue where IL-6 knockdown was combined with cisplatin treatment as compared with tissue receiving cisplatin alone.

Conclusions

IL-6 knockdown can increase chemo-drug efficacy of cisplatin, inhibit tumor growth and reduce the potential for tumor recurrence and metastasis in laryngeal cancer. The IL-6/STAT3/HIF1 pathway may represent an important target for investigating therapeutic strategies for the treatment of laryngeal cancer.

Krüppel-like factor 4 contributes to the pathogenesis of mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive subtype of B-cell non-Hodgkin lymphoma (NHL) with poor prognosis. Krüppel-like factor 4 (KLF4) has been reported as a bi-regulator in malignancies, but little is known about its role in MCL. Here, we showed that KLF4 was downregulated in three MCL cell lines and lymph nodes from MCL patients, which resulted in a negative prognosis. We also found that the regulation of KLF4 could inhibit the proliferation and induce apoptosis of Jeko-1 cells. The lentivirally over-expressed KLF4 protein was found bind to β-catenin and could inhibit downstream molecules such as cyclinD1 and c-Myc. Furthermore, 5-azacytidine could decrease the expression of methyltransferase-1 (DNMT-1) and restore the KLF4 expression in MCL cell lines, indicating that methylation might play an important role in the downregulation of KLF4. KLF4 may be a potential therapeutic target as a tumor suppressor in MCL.

Identification and characterization of CD133+CD44+ cancer stem cells from human laryngeal squamous cell carcinoma cell lines

Background: Laryngeal squamous cell carcinoma ranks second among head and neck squamous-cell carcinomas. Cancer stem cells can support cancer growth and malignant behavior. Therefore, cancer stem cells isolated from laryngeal squamous cell carcinoma tissue could be used to investigate the initiation, progression, and treatment strategies of this cancer. Methods: We isolated CD133-CD44-, CD133-CD44+, CD133+CD44- and CD133+CD44+ cell populations from laryngeal squamous-cell carcinoma cell lines Hep2 and TU-177 by magnetic-activated cell sorting. Sphere formation, cell proliferation, migration, invasion, colony formation, resistance to radio- and chemotherapy, and in vivo tumorigenicity of these populations were evaluated. Moreover, we investigated the expression of the stem-cell markers (sex determining region Y)-box 2 (SOX2) and octamer-binding transcription factor 4 (OCT4) in CD133-CD44-, CD133-CD44+, CD133+CD44-, CD133+CD44+ cell populations and parental Hep2 and TU-177 cells. Results: As compared with CD133-CD44-, CD133-CD44+, CD133+CD44- populations and parental cells, CD133+CD44+ cells showed higher cell viability, migration and invasive capability and colony formation ability as well as stronger resistance to cisplatin and irradiation. Moreover, levels of SOX2 and OCT4 and tumorigenicity in nude mice were greater in CD133+CD44+ Hep2 and TU-177 cells than other cell populations and parental cells. Conclusion: The CD133+CD44+ population of laryngeal squamous-cell carcinoma Hep2 and TU-177 cells have stem cell properties and showed more malignant features than CD133+CD44- and CD133-CD44+ cell populations. CD133+CD44+ cancer stem cells may be a promising target for developing anticancer drugs and treatment strategies for laryngeal squamous cell carcinoma.

Dissecting the biological relationship between TCGA miRNA and mRNA sequencing data using MMiRNA-Viewer

Background

MicroRNAs (miRNA) are short nucleotides that interact with their target genes through 3′ untranslated regions (UTRs). The Cancer Genome Atlas (TCGA) harbors an increasing amount of cancer genome data for both tumor and normal samples. However, there are few visualization tools focusing on concurrently displaying important relationships and attributes between miRNAs and mRNAs of both cancer tumor and normal samples. Moreover, a deep investigation of miRNA-mRNA target and biological relationships across multiple cancer types by integrating web-based analysis has not been thoroughly conducted.

Results

We developed an interactive visualization tool called MMiRNA-Viewer that can concurrently present the co-relationships of expression between miRNA-mRNA pairs of both tumor and normal samples into a single graph. The input file of MMiRNA-Viewer contains the expression information including fold changes between normal and tumor samples for mRNAs and miRNAs, the correlation between mRNA and miRNA, and the predicted target relationship by a number of databases. Users can also load their own input data into MMiRNA-Viewer and visualize and compare detailed information about cancer-related gene expression changes, and also changes in the expression of transcription-regulating miRNAs.

To validate the MMiRNA-Viewer, eight types of TCGA cancer datasets with both normal and control samples were selected in this study and three filter steps were applied subsequently. We performed Gene Ontology (GO) analysis for genes available in final selected 238 pairs and also for genes in the top 5 % (95 percentile) for each of eight cancer types to report a significant number of genes involved in various biological functions and pathways. We also calculated various centrality measurement matrices for the largest connected component(s) in each of eight cancers and reported top genes and miRNAs with high centrality measurements.

Conclusions

With its user-friendly interface, dynamic visualization and advanced queries, we also believe MMiRNA-Viewer offers an intuitive approach for visualizing and elucidating co-relationships between miRNAs and mRNAs of both tumor and normal samples. We suggest that miRNA and mRNA pairs with opposite fold changes of their expression and with inverted correlation values between tumor and normal samples might be most relevant for explaining the decoupling of mRNAs and their targeting miRNAs in tumor samples for certain cancer types.

Electronic supplementary material

The online version of this article (doi:10.1186/s12859-016-1219-y) contains supplementary material, which is available to authorized users.

A Meta-Analysis: Identification of Common Mir-145 Target Genes that have Similar Behavior in Different GEO Datasets

BACKGROUND

MicroRNAs, which are small regulatory RNAs, post-transcriptionally regulate gene expression by binding 3'-UTR of their mRNA targets. Their deregulation has been shown to cause increased proliferation, migration, invasion, and apoptosis. miR-145, an important tumor supressor microRNA, has shown to be downregulated in many cancer types and has crucial roles in tumor initiation, progression, metastasis, invasion, recurrence, and chemo-radioresistance. Our aim is to investigate potential common target genes of miR-145, and to help understanding the underlying molecular pathways of tumor pathogenesis in association with those common target genes.

METHODS

Eight published microarray datasets, where targets of mir-145 were investigated in cell lines upon mir-145 over expression, were included into this study for meta-analysis. Inter group variabilities were assessed by box-plot analysis. Microarray datasets were analyzed using GEOquery package in Bioconducter 3.2 with R version 3.2.2 and two-way Hierarchical Clustering was used for gene expression data analysis.

RESULTS

Meta-analysis of different GEO datasets showed that UNG, FUCA2, DERA, GMFB, TF, and SNX2 were commonly downregulated genes, whereas MYL9 and TAGLN were found to be commonly upregulated upon mir-145 over expression in prostate, breast, esophageal, bladder cancer, and head and neck squamous cell carcinoma. Biological process, molecular function, and pathway analysis of these potential targets of mir-145 through functional enrichments in PPI network demonstrated that those genes are significantly involved in telomere maintenance, DNA binding and repair mechanisms.

CONCLUSION

As a conclusion, our results indicated that mir-145, through targeting its common potential targets, may significantly contribute to tumor pathogenesis in distinct cancer types and might serve as an important target for cancer therapy.