MicroRNA aberrances in head and neck cancer: pathogenetic and clinical significance

A pilot study to evaluate the expression of microRNA‑let‑7a in patients with intestinal‑type sinonasal adenocarcinoma

Despite its histological resemblance to colorectal adenocarcinoma, there is little information about the molecular events involved in the pathogenesis of intestinal-type sinonasal adenocarcinoma (ITAC). The present study investigated the possible role and clinical value of microRNA (miR)-let-7a, a head and neck squamous cell carcinoma-related miR, in a well-characterized and homogeneous cohort of patients with ethmoidal ITAC associated with occupational exposure, treated by primary surgery. miR-let-7a expression levels were analyzed in 23 pairs of ethmoidal ITAC and adjacent normal formalin-fixed paraffin-embedded tissues by reverse transcription-quantitative PCR. The expression was evaluated in tumor and healthy tissues according to: Tumor grade (G) of differentiation and extension, and pTNM stage, and presence/absence of recurrence. Comparisons within and between groups were performed using two-tailed Student's paired t-test and one-way ANOVA with Tukey's post hoc test. P<0.05 was considered to indicate a statistically significant difference. miR-let-7a expression in ethmoidal ITAC tissues was significantly lower than that in adjacent normal tissues (P<0.05; mean expression level ± SD, 1.452707±1.4367189 vs. 4.094017±2.7465375). miR expression varied with pT stage. miR-let-7a was downregulated (P<0.05) in advanced stages (pT3-pT4) compared with earlier stages (pT1-pT2). Furthermore, downregulation of miR-let-7a in ITAC was associated with poorly-differentiated (G3) cancer (P<0.05). No other associations were observed between miR-let-7a expression and the other clinicopathological parameters, including disease-free survival. In conclusion, downregulation of miR-let-7a in ITAC was associated with advanced-stage (pT3 and pT4) and poorly-differentiated (G3) disease, suggesting that the mutation of this gene, combined with additional genetic events, could serve a role in ITAC pathogenesis.

miRNAs, Mesenchymal Stromal Cells and Major Neoplastic and Inflammatory Skin Diseases: A Page Being Written: A Systematic Review

Micro RNAs (miRNAs) are a type of non-coding RNA (ncRNA) and typically interact with specific target mRNAs through complementary base pairing, affecting their translation and/or stability. MiRNAs regulate nearly all cellular functions, including the cell fate of mesenchymal stromal cells (MSCs). It is now accepted that various pathologies arise at the stem level, and, in this scenario, the role played by miRNAs in the fate of MSCs becomes of primary concern. Here we have considered the existing literature in the field of miRNAs, MSCs and skin diseases, classified as inflammatory (such as psoriasis and atopic dermatitis-AD) and neoplastic (melanoma and non-melanoma-skin-cancer including squamous cell and basal cell carcinoma) diseases. In this scoping review article, the evidence recovered indicates that this topic has attracted attention, but it is still a matter of opinion. A protocol for this review was registered in PROSPERO with the registration number "CRD42023420245". According to the different skin disorders and to the specific cellular mechanisms considered (cancer stem cells, extracellular vesicles, inflammation), miRNAs may play a pro- or anti-inflammatory, as well as a tumor suppressive, or supporting, role, indicating a complex regulation of their function. It is evident that the mode of action of miRNAs is more than a switch on-off, and all the observed effects of their dysregulated expression must be checked in a detailed analysis of the targeted proteins. The involvement of miRNAs has been studied mainly for squamous cell carcinoma and melanoma, and much less in psoriasis and AD; different mechanisms have been considered, such as miRNAs included in extracellular vesicles derived both from MSCs or tumor cells, miRNAs involved in cancer stem cells formation, up to miRNAs as candidates to be new therapeutic tools.

Osteogenic and Adipogenic Differentiation Potential of Oral Cancer Stem Cells May Offer New Treatment Modalities

(1) Treatment failure of oral squamous cell carcinoma (OSCC) is generally due to the development of therapeutic resistance caused by the existence of cancer stem cells (CSCs), a small cell subpopulation with marked self-renewal and differentiation capacity. Micro RNAs, notably miRNA-21, appear to play an important role in OSCC carcinogenesis. Our objectives were to explore the multipotency of oral CSCs by estimating their differentiation capacity and assessing the effects of differentiation on stemness, apoptosis, and several miRNAs' expression. (2) A commercially available OSCC cell line (SCC25) and five primary OSCC cultures generated from tumor tissues obtained from five OSCC patients were used in the experiments. Cells harboring CD44, a CSC marker, were magnetically separated from the heterogeneous tumor cell populations. The CD44⁺ cells were then subjected to osteogenic and adipogenic induction, and the specific staining was used for differentiation confirmation. The kinetics of the differentiation process was evaluated by qPCR analysis of osteogenic (Bone Morphogenetic Protein-BMP4, Runt-related Transcription Factor 2-RUNX2, Alkaline Phosphatase-ALP) and adipogenic (Fibroblast Activation Protein Alpha-FAP, LIPIN, Peroxisome Proliferator-activated Receptor Gamma-PPARG) markers on days 0, 7, 14, and 21. Embryonic markers (Octamer-binding Transcription Factor 4-OCT4, Sex Determining Region Y Box 2-SOX2, and NANOG) and micro RNAs (miRNA-21, miRNA-133, and miRNA-491) were also correspondingly evaluated by qPCR. An Annexin V assay was used to assess the potential cytotoxic effects of the differentiation process. (3) Following differentiation, the levels of markers for the osteo/adipo lineages showed a gradual increase from day 0 to day 21 in the CD44⁺ cultures, while stemness markers and cell viability decreased. The oncogenic miRNA-21 also followed the same pattern of gradual decrease along the differentiation process, while tumor suppressor miRNA-133 and miRNA-491 levels increased. (4) Following induction, the CSCs acquired the characteristics of the differentiated cells. This was accompanied by loss of stemness properties, a decrease of the oncogenic and concomitant, and an increase of tumor suppressor micro RNAs.

The Prognostic Role of miR-31 in Head and Neck Squamous Cell Carcinoma: Systematic Review and Meta-Analysis with Trial Sequential Analysis

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide with high recurrence, metastasis, and poor treatment outcome. Prognostic survival biomarkers can be a valid tool for assessing a patient's life expectancy and directing therapy toward specific targets. Recent studies have reported microRNA (miR) might play a critical role in regulating different types of cancer. The main miR used as a diagnostic and prognostic biomarker and reported in the scientific literature for HNSCC is miR-21. Other miRs have been investigated to a lesser extent (miR-99a, miR-99b, miR-100, miR-143, miR-155, miR-7, miR-424, miR-183), but among these, the one that has attracted major interest is the miR-31.

METHODS

The systematic review was conducted following the PRISMA guidelines using electronic databases, such as PubMed, Scopus, and the Cochrane Central Register of Controlled Trials, with the use of combinations of keywords, such as miR-31 AND HNSCC, microRNA AND HNSCC, and miR-31. The meta-analysis was performed using the RevMan 5.41 software (Cochrane Collaboration, Copenhagen, Denmark).

RESULTS

This search produced 721 records, which, after the elimination of duplicates and the application of the inclusion and exclusion criteria, led to 4 articles. The meta-analysis was conducted by applying fixed-effects models, given the low rate of heterogeneity (I2 = 40%). The results of the meta-analysis report an aggregate hazard ratio (HR) for the overall survival (OS), between the highest and lowest miR-31 expression, of 1.59, with the relative intervals of confidence (1.22 2.07). Heterogeneity was evaluated through Chi2 = 5.04 df = 3 (p = 0.17) and the Higgins index I2 = 40; testing for the overall effect was Z = 3.44 (p = 0.00006). The forest plot shows us a worsening HR value of OS, in relation to the elevated expression of miR-31.

CONCLUSIONS

In conclusion, the data resulting from the current meta-analysis suggest that miR-31 is associated with the prognosis of patients with HNSCC and that elevated miR-31 expression could predict a poor prognosis in patients with this type of neoplasm.

Identification of key miRNAs and targeted genes involved in the progression of oral squamous cell carcinoma

Background/purpose

Oral squamous cell carcinoma (OSCC) is one of the most common types of head and neck squamous cell carcinoma. Accurate biomarkers are needed for early diagnosis and prognosis of OSCC. MicroRNAs (miRNAs) have shown great values in different types of cancers including OSCC. However, most of the miRNAs involved in the development of OSCC remain uncovered. This study aimed to identify hub miRNAs and mRNAs in OSCC.

Materials and methods

We explored the roles of key miRNAs, target genes and their relationships in OSCC using an integrated bioinformatics approach. Initially, Two OSCC microarray datasets from the Gene Expression Omnibus database were obtained to analyze miRNA expression. MiRNA-targeted mRNAs were acquired, and gene ontology/kyoto encyclopedia of genes and genomes analyses were performed. Thereafter, we constructed a protein–protein interaction (PPI) network to identify hub genes and a miRNA-mRNA interaction network was used to identify key miRNAs. Furthermore, differential gene expression and Kaplan–Meier Plotter survival analysis was performed to evaluate their potential clinical application values.

Results

Four upregulated, two downregulated miRNAs and 608 target genes of the differentially expressed miRNAs were identified. The PPI and miRNA-mRNA interaction networks highlighted 10 hub genes and two key miRNAs, and pathway analyses showed their correlative involvement in tumorigenesis-related processes. Of these miRNAs and genes, miR-125b, β-actin, vinculin and histone deacetylase 1 were correlated with overall survival (P < 0.05).

Conclusion

These findings indicate that miR-21 and miR-125b, associated with the 10 hub genes, jointly participate in OSCC tumorigenesis, offering insight into the molecular mechanisms underlying OSCC as potential targets for early diagnosis, treatment and prognosis.

Circ_0005033 is an oncogene in laryngeal squamous cell carcinoma and regulates cell progression and Cisplatin sensitivity via miR-107/IGF1R axis

Transcriptome expression profiles of laryngeal squamous cell carcinoma (LSCC) are altered, and we aimed to investigate expression and role of hsa_circ_0005033 (circ_0005033), microRNA (miR)-107 and insulin-like growth factor 1 receptor (IGF1R) in LSCC. Real-time PCR, western blotting and immunohistochemistry detected RNA and protein expression levels. Functional assays were performed using MTT assay, EdU assay, apoptosis assay, flow cytometry, Transwell assay, and xenograft tumor model. Direct interaction was predicted by Starbase algorithm and validated by dual-luciferase reporter assay and RNA immunoprecipitation. Expression of circ_0005033 was substantially upregulated in LSCC tissues and cells, and allied with miR-107 downregulation and IGF1R upregulation. Circ_0005033 showed a closed-loop structure and long half-life. Essentially, circ_0005033 and IGF1R were competing endogenous RNAs for miR-107 via target binding. Silencing circ_0005033 facilitated apoptosis rate and lowered cell viability, proliferation, migration and invasion of LSCC cells, as well as delayed xenograft tumor growth. Allied with that, cleaved-caspase 3/8/9 expression was elevated via death receptor-mediated and mitochondrial pathways, and expression of matrix metalloproteinase-2 (MMP2), MMP9, cyclin D1 and proliferating cell nuclear antigen was decreased. Moreover, Cisplatin-induced inhibition of cell viability was exacerbated by inhibiting circ_0005033. These functional effects of circ_0005033 depression were consistent with those of miR-107 overexpression. Furthermore, depleting miR-107 and restoring IGF1R abated the effects of circ_0005033 knockdown and miR-107 overexpression, respectively. Circ_0005033 was oncogenic in LSCC by regulating cell progression and Cisplatin sensitivity at least via miR-107/IGF1R axis.

MiRNome analysis identifying miR-205 and miR-449a as biomarkers of disease progression in intestinal-type sinonasal adenocarcinoma

BACKGROUND

Patients with intestinal-type sinonasal adenocarcinoma (ITAC) have an unfavorable prognosis, and new diagnostic and therapeutic approaches are needed to improve clinical management.

METHODS

Next-generation sequencing-based miRNome analysis was performed on 43 ITAC patients who underwent surgical resection, and microRNA (miRNA) data were obtained from 35 cases. Four miRNAs were identified, and their expression levels were detected by reverse-transcription quantitative polymerase chain reaction and related to the relevant patient outcome. Overall survival and disease-free survival rates were evaluated through the Kaplan-Meier method and log-rank test, and multivariate analysis was performed by means of Cox proportional hazard analysis.

RESULTS

High levels of miR-205 and miR-34c/miR-449 cluster expression were associated with an increased recurrence risk and, therefore, a worse prognosis. Multivariate analysis confirmed that miR-205 and miR-449 were significant prognostic predictors.

CONCLUSIONS

A high expression of miR-205 and miR-449 is independent predictors of poor survival for ITAC patients.

Systemic Investigation Identifying Salivary miR-196b as a Promising Biomarker for Early Detection of Head-Neck Cancer and Oral Precancer Lesions

Background: Liquid biopsy is a rapidly growing field, for it may provide a minimally invasive way to acquire pathological data for personalized medicine. This study developed a systemic strategy to discover an effective salivary biomarker for early detection of patients with head-neck squamous carcinoma (HNSC) and oral precancer lesion (OPC). Methods: A total of 10 miRNAs were examined in parallel with multiple independent cohorts. These included a training set of salivary samples from HNSC patients, the TCGA-HNSC and GSE31277 cohorts to differentiate miRNAs between tumor and normal tissues, and groups of salivary samples from healthy individuals, patients with HNSC and OPC. Results: The combined results from the salivary training set and the TCGA-HNSC cohort showed that four miRNAs (miR-148b, miR-155, miR-196b, and miR-31) consistently increased in HNSC patients. Further integration with the GSE31277 cohort, two miRNAs (miR-31 and miR-196b) maintained at high significances. Further assessment showed that salivary miR-196b was a prominent diagnostic biomarker, as it remarkably discriminated between healthy individuals and patients with HNSC (p < 0.0001, AUC = 0.767, OR = 5.64) or OPC (p < 0.0001, AUC = 0.979, OR = 459). Conclusion: Salivary miR-196b could be an excellent biomarker for diagnosing OPC and early detection of HNSC. This molecule may be used for early screening high-risk groups of HNSC.

The upregulation of oncogenic miRNAs in swabbed samples obtained from oral premalignant and malignant lesions

OBJECTIVES

Oncogenic miRNAs upregulated in OSCC play a range of versatile roles in oral carcinogenesis. Oral potentially malignant disorders (OPMDs) are the antecedent lesions to oral squamous carcinoma (OSCC) and they require a definitive diagnosis and early intervention. This study hypothesizes the presence of aberrant oncogenic miRNA expression in swabbed oral lesions.

MATERIALS AND METHODS

The expression of miR-21, miR-31, miR-134, miR-146a, and miR-211 in swabbed samples from 36 dysplastic or hyperplastic OPMDs and 10 OSCCs, relative to respective normal mucosa within the same patient, is analyzed with qRT-PCR to develop a diagnosis.

RESULTS

Upregulation of all tested miRNAs in OPMD and OSCC samples comparing to controls is found to have occurred. Receiver operating characteristics curve analysis shows that miR-31 gives the best diagnostic accuracy of 0.91 when differentiating OPMD/OSCC from controls. An analysis of miR-134 and miR-211 expression allows the discrimination of the dysplastic state associated with OPMD, while the use of expression of the combined miRNAs further improves the analytical performances when identifying the dysplastic state. The concordant upregulation of miR-21, miR-31, and miR-146a is found to occur during an early stage of OSCC carcinogenesis.

CONCLUSION

This study demonstrates the upregulation of multiple oncogenic miRNAs in swabbed OPMD and OSCC samples. miRNA expression in swabbed collectives enables the differentiation between normal mucosa and OPMD/OSCC, independent of their histopathological severity.

CLINICAL RELEVANCE

This conventional and convenient sampling tool, when coupled with an assessment of miR-31 expression, would seem to be an adjuvant approach to the diagnosis of OPMD and OSCC.

Knockdown circular RNA circGFRA1 inhibits glioma cell proliferation and migration by upregulating microRNA-99a

Glioma is the most widespread and malignant brain tumor in the central nervous system of adult, causing multiple cancer-associated deaths worldwide. Here, we identified the impact of circGFRA1 on glioma, and aimed to uncover the underlying molecular mechanism. The expression of circGFRA1 of glioma specimens was evaluated by using quantitative reverse transcription PCR. Cell viability, proliferation, colony formation, apoptosis and migration were estimated utilizing CCK-8, EdU staining, colony formation assay, TUNEL staining and Transwell assay, respectively. Bioinformatics analysis, luciferase assay and RNA co-immunoprecipitation was utilized for verification of direct binding between circGFRA1 and miR-99a. Western blot was applied to investigate protein expression in U251 cells. The results showed that circGFRA1 expression was overexpressed in glioma specimens. Knockdown circGFRA1 declined viability, colony formation, proliferation and migrative potential, but enhanced U251 cell apoptosis. Moreover, circGFRA1 acts as a microRNA sponge for miR-99a. Furthermore, miR-99a was involved in the circGFRA1-regulated glioma cell behaviors. Silencing circGFRA1 reduced p/t-AKT, p/t-FOXO1 and p/t-mTOR expression levels via upregulating miR-99a expression. In conclusion, our study demonstrated that knockdown circGFRA1 inhibits glioma cell proliferation and migration by upregulating microRNA-99a.

The role of hypoxia in the tumor microenvironment and development of cancer stem cell: a novel approach to developing treatment

Hypoxia is a common feature of solid tumors, and develops because of the rapid growth of the tumor that outstrips the oxygen supply, and impaired blood flow due to the formation of abnormal blood vessels supplying the tumor. It has been reported that tumor hypoxia can: activate angiogenesis, thereby enhancing invasiveness and risk of metastasis; increase survival of tumor, as well as suppress anti-tumor immunity and hamper the therapeutic response. Hypoxia mediates these effects by several potential mechanisms: altering gene expression, the activation of oncogenes, inactivation of suppressor genes, reducing genomic stability and clonal selection. We have reviewed the effects of hypoxia on tumor biology and the possible strategiesto manage the hypoxic tumor microenvironment (TME), highlighting the potential use of cancer stem cells in tumor treatment.

Cerina: systematic circRNA functional annotation based on integrative analysis of ceRNA interactions

Circular RNAs, a family of covalently circularized RNAs with tissue-specific expression, were recently demonstrated to play important roles in mammalian biology. Regardless of extensive research to predict, quantify, and annotate circRNAs, our understanding of their functions is still in its infancy. In this study, we developed a novel computational tool: Competing Endogenous RNA for INtegrative Annotations (Cerina), to predict biological functions of circRNAs based on the competing endogenous RNA model. Pareto Frontier Analysis was employed to integrate ENCODE mRNA/miRNA data with predicted microRNA response elements to prioritize tissue-specific ceRNA interactions. Using data from several circRNA-disease databases, we demonstrated that Cerina significantly improved the functional relevance of the prioritized ceRNA interactions by several folds, in terms of precision and recall. Proof-of-concept studies on human cancers and cardiovascular diseases further showcased the efficacy of Cerina on predicting potential circRNA functions in human diseases.

Differential expression of microRNAs in the hippocampi of male and female rodents after chronic alcohol administration

Background

Women are more vulnerable than men to the neurotoxicity and severe brain damage caused by chronic heavy alcohol use. In addition, brain damage due to chronic heavy alcohol use may be associated with sex-dependent epigenetic modifications. This study aimed to identify microRNAs (miRNAs) and their target genes that are differentially expressed in the hippocampi of male and female animal models in response to alcohol.

Methods

After chronic alcohol administration (3~3.5 g/kg/day) in male (control, n = 10; alcohol, n = 12) or female (control, n = 10; alcohol, n = 12) Sprague-Dawley rats for 6 weeks, we measured body weights and doublecortin (DCX; a neurogenesis marker) concentrations and analyzed up- or downregulated miRNAs using GeneChip miRNA 4.0 arrays. The differentially expressed miRNAs and their putative target genes were validated by RT-qPCR.

Results

Alcohol attenuated body weight gain only in the male group. On the other hand, alcohol led to increased serum AST in female rats and decreased serum total cholesterol concentrations in male rats. The expression of DCX was significantly reduced in the hippocampi of male alcohol-treated rats. Nine miRNAs were significantly up- or downregulated in male alcohol-treated rats, including upregulation of miR-125a-3p, let-7a-5p, and miR-3541, and downregulation of their target genes (Prdm5, Suv39h1, Ptprz1, Mapk9, Ing4, Wt1, Nkx3-1, Dab2ip, Rnf152, Ripk1, Lin28a, Apbb3, Nras, and Acvr1c). On the other hand, 7 miRNAs were significantly up- or downregulated in alcohol-treated female rats, including downregulation of miR-881-3p and miR-504 and upregulation of their target genes (Naa50, Clock, Cbfb, Arih1, Ube2g1, and Gng7).

Conclusions

These results suggest that chronic heavy alcohol use produces sex-dependent effects on neurogenesis and miRNA expression in the hippocampus and that sex differences should be considered when developing miRNA biomarkers to diagnose or treat alcoholics.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-020-00342-3.

Imaging-Genomic Study of Head and Neck Squamous Cell Carcinoma: Associations Between Radiomic Phenotypes and Genomic Mechanisms via Integration of The Cancer Genome Atlas and The Cancer Imaging Archive

PURPOSE

Recent data suggest that imaging radiomic features of a tumor could be indicative of important genomic biomarkers. Understanding the relationship between radiomic and genomic features is important for basic cancer research and future patient care. We performed a comprehensive study to discover the imaginggenomic associations in head and neck squamous cell carcinoma (HNSCC) and explore the potential of predicting tumor genomic alternations using radiomic features.

METHODS

Our retrospective study integrated whole-genome multiomics data from The Cancer Genome Atlas with matched computed tomography imaging data from The Cancer Imaging Archive for the same set of 126 patients with HNSCC. Linear regression and gene set enrichment analysis were used to identify statistically significant associations between radiomic imaging and genomic features. Random forest classifier was used to predict the status of two key HNSCC molecular biomarkers, human papillomavirus and disruptive TP53 mutation, on the basis of radiomic features.

RESULTS

Widespread and statistically significant associations were discovered between genomic features (including microRNA expression, somatic mutations, and transcriptional activity, copy number variations, and promoter region DNA methylation changes of pathways) and radiomic features characterizing the size, shape, and texture of tumor. Prediction of human papillomavirus and TP53 mutation status using radiomic features achieved areas under the receiver operating characteristic curve of 0.71 and 0.641, respectively.

CONCLUSION

Our exploratory study suggests that radiomic features are associated with genomic characteristics at multiple molecular layers in HNSCC and provides justification for continued development of radiomics as biomarkers for relevant genomic alterations in HNSCC.

Emerging molecular functions of microRNA-124: Cancer pathology and therapeutic implications

MicroRNAs are characterized as small, single-stranded, non-coding RNA molecules that bind to their target mRNA to prevent protein synthesis. MicroRNAs regulate various normal processes; however, they are aberrantly regulated in many cancers. They control the expression of various genes, including cancer-related genes. This causes microRNAs to be considered as a good target for further investigations for designing novel therapeutic strategies. Since miR124 is known for some time already, it has a tumor-suppressing role in various cancers. Numerous studies indicate its definite roles in malignant processes such as epithelial-to-mesenchymal transition, cell cycle arrest, metastasis, cancer stem cell formation and induction of apoptosis. However, some studies have indicated a dual role for miR-124 in oncogenic processes like autophagy and multi-drug resistance. In this article, we will review recent researches on the biological functions and clinical implications of miR-124. Subsequently, we will discuss future perspectives in terms of the roles of this miRNA in cancers.

The let-7 family of microRNAs suppresses immune evasion in head and neck squamous cell carcinoma by promoting PD-L1 degradation

Background

Accumulation of immunosuppressive protein programmed death-ligand 1 (PD-L1) has been documented in several cancers and contributes to the evasion of the host immune system. However, cancer cell-intrinsic signaling-dependent control of PD-L1 expression remains to be elucidated. Herein, we aimed to identify the let-7 family of microRNAs as candidates that up-regulate tumor cell PD-L1 expression and mediates immune evasion of head and neck squamous cell carcinoma (HNSCC).

Methods

The expression of let-7 family and PD-L1 was quantified in HNSCC tissues and adjacent normal tissues. PD-L1 degradation was evaluated in HNSCC cells in response to elevated expressions of let-7a or let-7b. The regulation of let-7 family on PD-L1 degradation through a mechanism involving T-cell factor-4 (TCF-4) control of β-catenin/STT3 pathway was evaluated. Immune recognition of HNSCC in vivo was examined in subcutaneous tumor-bearing C3H mice in the presence of let-7a/b and/or CTLA-4 antibody.

Results

The let-7 family were significantly down-regulated in the context of HNSCC, sharing a negative correlation with PD-L1 expression. Glycosylated PD-L1 was detected in HNSCC cells, which was reduced by let-7a/b over-expression. TCF-4, the target of let-7a/b, activated the β-catenin/STT3 pathway and promoted PD-L1 degradation. In vivo analysis demonstrated that let-7a/b over-expression potentiated anticancer immunotherapy by CTLA-4 blockade.

Conclusions

Taken together, our findings highlight targeting let-7 family as a potential strategy to enhance immune checkpoint therapy for HNSCC.

MicroRNA targeting by quercetin in cancer treatment and chemoprotection

A growing number of evidences from clinical and preclinical studies have shown that dysregulation of microRNA (miRNA) function contributes to the progression of cancer and thus miRNA can be an effective target in therapy. Dietary phytochemicals, such as quercetin, are natural products that have potential anti-cancer properties due to their proven antioxidant, anti-inflammatory, and anti-proliferative effects. Available experimental studies indicate that quercetin could modulate multiple cancer-relevant miRNAs including let-7, miR-21, miR-146a and miR-155, thereby inhibiting cancer initiation and development. This paper reviews the data supporting the use of quercetin for miRNA-mediated chemopreventive and therapeutic strategies in various cancers, with the aim to comprehensively understand its health-promoting benefits and pharmacological potential. Integration of technology platforms for miRNAs biomarker and drug discovery is also presented.

Role of miRNA-Regulated Cancer Stem Cells in the Pathogenesis of Human Malignancies

Recent biomedical discoveries have revolutionized the concept and understanding of carcinogenesis, a complex and multistep phenomenon which involves accretion of genetic, epigenetic, biochemical, and histological changes, with special reference to MicroRNAs (miRNAs) and cancer stem cells (CSCs). miRNAs are small noncoding molecules known to regulate expression of more than 60% of the human genes, and their aberrant expression has been associated with the pathogenesis of human cancers and the regulation of stemness features of CSCs. CSCs are the small population of cells present in human malignancies well-known for cancer resistance, relapse, tumorigenesis, and poor clinical outcome which compels the development of novel and effective therapeutic protocols for better clinical outcome. Interestingly, the role of miRNAs in maintaining and regulating the functioning of CSCs through targeting various oncogenic signaling pathways, such as Notch, wingless (WNT)/β-Catenin, janus kinases/ signal transducer and activator of transcription (JAK/STAT), phosphatidylinositol 3-kinase/ protein kinase B (PI3/AKT), and nuclear factor kappa-light-chain-enhancer of activated B (NF-kB), is critical and poses a huge challenge to cancer treatment. Based on recent findings, here, we have documented the regulatory action or the underlying mechanisms of how miRNAs affect the signaling pathways attributed to stemness features of CSCs, such as self-renewal, differentiation, epithelial to mesenchymal transition (EMT), metastasis, resistance and recurrence etc., associated with the pathogenesis of various types of human malignancies including colorectal cancer, lung cancer, breast cancer, head and neck cancer, prostate cancer, liver cancer, etc. We also shed light on the fact that the targeted attenuation of deregulated functioning of miRNA related to stemness in human carcinogenesis could be a viable approach for cancer treatment.

miR-31-5p Is a Potential Circulating Biomarker and Therapeutic Target for Oral Cancer

MicroRNAs have been proposed as novel biomarkers for the diagnosis and treatment of many types of cancer. The levels of five candidate microRNAs (miRNAs) (miR-99a-5p, miR-31-5p, miR-138-5p, miR-21-5p, and miR-375-3p) in sera from oral cancer patients and paired tumor and normal tissues were detected by real-time qPCR. The diagnostic power of these miRNAs was analyzed by receiver operating characteristic (ROC) curves. Patient-derived xenograft (PDX) models of oral cancer were established and utilized to verify the potential therapeutic effect of miR-31-5p. Candidate miRNAs were screened from our previous studies and verified in 11 paired oral cancer and adjacent normal tissues. Only serum miR-31-5p levels were significantly different between oral cancer patients and healthy controls and between pre- and postoperative patients. Based on the logistic regression model, this panel of five miRNAs distinguished oral cancer patients from healthy control, with an area under the ROC curve (AUC) of 0.776 (sensitivity = 76.8% and specificity = 73.6%). Furthermore, a miR-31-5p mimic enhanced the proliferation of normal epithelial cells, and antagomiR-31-5p inhibited the proliferation of oral cancer cells in vitro. In vivo, antagomiR-31-5p significantly inhibited tumor growth in oral cancer PDX models. Our findings suggest that circulating miR-31-5p might act as an independent biomarker for oral cancer diagnosis and could serve as a therapeutic target for oral cancer.

MicroRNA-16 functions as a tumor-suppressor gene in oral squamous cell carcinoma by targeting AKT3 and BCL2L2

Aberrant expressions of microRNAs have been reported to be strongly associated with the progression and prognosis of various tumors, including oral squamous cell carcinoma (OSCC). Recent studies on miRNA expression profiling have suggested that microRNA-16 (miR-16) may be dysregulated in OSCC. However, the tumorigenic roles and mechanisms of miR-16 in OSCC are still largely unknown. In this study, we demonstrated that miR-16 was specifically downregulated in both OSCC patients and cancer cell lines. In addition, functional roles of miR-16 in vitro suggested that the miR-16 mimic inhibited cell proliferation and induced apoptosis, whereas miR-16 inhibitor displayed the opposite effects. Luciferase reporter assay and correlation analysis showed that AKT3 and BCL2L2 were directly targeted by miR-16 and were inversely expressed with miR-16 in OSCC. Moreover, restoration of AKT3 and BCL2L2 expression could partially reverse the cell proliferation inhibition and apoptosis induction caused by miR-16. In xenograft nude mice, miR-16 mimics decreased the expression of AKT3 and BCL2L2 and reduced the tumors volumes and weights, whereas the miR-16 inhibitor exhibited adverse effects in the derived xenografts. In conclusion, the findings suggested that miR-16 functions as a tumor suppressor miRNA to inhibit cell proliferation and induce apoptosis in OSCC through decreasing the oncogenes AKT3 and BCL2L2 and that miR-16 could be a potential therapeutic target for OSCC.

Epithelial-mesenchymal transition and microRNAs: Challenges and future perspectives in oral cancer

BACKGROUND

Head and neck cancer is the sixth most common cancer worldwide, with oral squamous cell carcinoma (OSCC) being the most representative type. OSCC is a public health problem with high morbidity and poor survival rate. Epithelial-mesenchymal transition is emerging as a hallmark in OSCC.

METHODS

In this study, we described the role of microRNAs in epithelial-mesenchymal transition regulation in OSCC based on a PubMed search using articles published in English between January 1, 2010, and January 31, 2018.

RESULTS

MicroRNA's regulatory networks seem to be a hallmark of epithelial-mesenchymal transition in OSCC pathophysiology becoming a growing challenge to design new studies and strategies from biology to clinical applications.

CONCLUSION

Therefore, we propose that targeting therapies to epithelial-mesenchymal transition-type cells, namely, coordinating microRNAs and/or hydrophobic drugs, such as conventional therapy, could be a promising strategy to improve the outcomes of patients with OSCC.

MiR-124 acts as a tumor suppressor by inhibiting the expression of sphingosine kinase 1 and its downstream signaling in head and neck squamous cell carcinoma

By analyzing the expression profile of microRNAs in head and neck squamous cell carcinomas (HNSCC), we found that the expression level of miR-124 was 4.59-fold lower in tumors than in normal tissues. To understand its functions, we generated a miR-124-expressing subline (JHU-22^miR124) and a mock vector-transfected subline (JHU-22^vec) by transfecting the mimic of miR-124 into JHU-22 cancer cells. Restored expression of miR-124 in JHU-22^miR124 cells led to reduced cell proliferation, delayed colony formation, and decreased tumor growth, indicating a tumor-suppressive effect of miR-124. Subsequent target search revealed that the 3′-UTR of SphK1 mRNA carries a complementary site for the seed region of miR-124. SphK1 was also detected to be overexpressed in HNSCC cell lines, but down-expressed in JHU-22^miR124 cells and tumor xenografts. These results suggest that SphK1 is a target of miR-124. To confirm this finding, we constructed a 3′-UTR-Luc-SphK1 vector and a binding site-mutated luciferase reporter vector. Co-transfection of 3′-UTR-Luc-SphK1 with miR-124 expression vector exhibited a 9-fold decrease in luciferase activity compared with mutated vector, suggesting that miR-124 inhibits SphK1 activity directly. Further studies on downstream signaling demonstrated accumulation of ceramide, increased expression of the pro-apoptotic Bax, BAD and PARP, decreased expression of the anti-apoptotic Bcl-2 and Bcl-xL, and enhanced expression of cytochrome c and caspase proteins in JHU-22^miR124 compared with JHU-22^vec cells and tumor xenografts. We conclude that miR-124 acts as a tumor suppressor in HNSCC by directly inhibiting SphK1 activity and its downstream signals.

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

miR-31 is oncogenic for head and neck squamous cell carcinoma (HNSCC). Proteins containing the AT-rich interacting domain (ARID) modulate the accessibility of chromatin to the transcription machinery needed for gene expression. In this study, we showed that miR-31 was able to target ARID1A in HNSCC. HNSCC tumors had an inverse miR-31 and ARID1A expression. miR-31 associated oncogenicities were rescued by ARID1A expression in HNSCC cells. Furthermore, ARID1A repressed the stemness properties and transcriptional activity of Nanog/OCT4/Sox2/EpCAM via the protein's affinity for AT-rich sites within promoters. HNSCC patients with tumors having high level of miR-31 expression and high levels of Nanog/OCT4/Sox2/EpCAM expression, together with low level of ARID1A expression, were found to have the worst survival. This study provides novel mechanistic clues demonstrating that miR-31 inhibits ARID1A and that this enriches the oncogenicity and stemness of HNSCC.

Up-regulation of miR-187 modulates the advances of oral carcinoma by targeting BARX2 tumor suppressor

Oral squamous cell carcinoma (OSCC) is one of the most common cancers worldwide. Aberrations in miRNA regulation are known to play important roles in OSCC pathogenesis. miR-187 was shown to be up-regulated in head and neck malignancies in our previous screening. This study further investigated the oncogenic potential, clinical implications, and targets of miR-187 in OSCC. We observed that miR-187 increased oncogenicity, particularly migration, of OSCC cells. miR-187 expression increased the xenografic tumorigenicity and metastasis in mice. In addition, metastatic human OSCC had higher miR-187 expression than did non-metastatic tumors. Through vigorous screening, we confirmed BarH-like Homeobox 2 (BARX2) gene as an miR-187 target. BARX2 expression suppressed the migration, invasion, anchorage-independent colony formation, and orthotopic tumorigenesis of OSCC cells. The migratory phenotype and neck metastasis induced by miR-187 was rescued by BARX2 expression. BARX2 expression was down-regulated in the vast majority of OSCC, and this down-regulation was particularly conspicuous in tumors with advanced nodal metastasis. In addition, plasma miR-187 was significantly higher in OSCC patients than in normal individuals. This study highlights the roles of miR-187-BARX2 in driving the carcinogenesis of OSCC. The results suggest that miR-187 is a potential serological marker for OSCC and that targeting of miR-187 might prove effective in attenuating nodal metastasis.

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

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

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

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

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

MicroRNA-196a-5p is a potential prognostic marker of delayed lymph node metastasis in early-stage tongue squamous cell carcinoma

MicroRNAs (miRs) are expected to serve as prognostic tools for cancer. However, many miRs have been reported as prognostic markers of recurrence or metastasis in oral squamous cell carcinoma patients. We aimed to determine the prognostic markers in early-stage tongue squamous cell carcinoma (TSCC). Based on previous studies, we hypothesized that miR-10a, 10b, 196a-5p, 196a-3p, and 196b were prognostic markers and we retrospectively performed miR expression analyses using formalin-fixed paraffin-embedded sections of surgical specimens. Total RNA was isolated from cancer tissues and adjacent normal tissue as control, and samples were collected by laser-capture microdissection. After cDNA synthesis, reverse transcription-quantitative polymerase chain reaction was performed. Statistical analyses for patient clinicopathological characteristics, recurrence/metastasis, and survival rates were performed to discern their relationships with miR expression levels, and the 2^−ΔΔCq method was used. miR-196a-5p levels were significantly upregulated in early-stage TSCC, particularly in the lymph node metastasis (LNM) group. The LNM-free survival rate in the low miR-196a-5p ΔΔCq value regulation group was found to be lower than that in the high ΔΔCq value regulation group (P=0.0079). Receiver operating characteristic analysis of ΔΔCq values revealed that miR-196a-5p had a P-value=0.0025, area under the curve=0.740, and a cut-off value=−0.875 for distinguishing LNM. To our knowledge, this is the first study to examine LNM-related miRs in early-stage TSCC as well as miRs and ‘delayed LNM’ in head and neck cancer. miR-196a-5p upregulation may predict delayed LNM. Our data serve as a foundation for future studies to evaluate miR levels and facilitate the prediction of delayed LNM during early-stage TSCC, which prevent metastasis when combined with close follow-up and aggressive adjuvant therapy or elective neck dissection. Moreover, our data will serve as a foundation for future studies to evaluate whether miR-196a-5p can serve as a therapeutic marker for preventing metastasis.

Deregulation of selected microRNAs in sinonasal carcinoma: Value of miR-21 as prognostic biomarker in sinonasal squamous cell carcinoma

BACKGROUND

Tumors occurring in the sinonasal area are characterized by unfavorable outcome due to difficult diagnosis, treatment, and prognosis of the disease corresponding with the anatomic complexity of the area.

METHODS

We used quantitative real-time polymerase chain reaction (PCR) to compare relative expression of miR-21, miR-141, and miR-200c in 70 formalin-fixed, paraffin-embedded samples of sinonasal carcinoma tissue (majority of squamous cell carcinoma [SCC] samples) with 17 control samples of sinonasal tissue.

RESULTS

Our data showed significant upregulation of miR-21 in sinonasal cancer tissue. Expression levels of miR-141 and miR-200c were below detectable levels in both sinonasal cancer samples and healthy tissue. Kaplan-Meier analysis with log-rank survival showed that patients with SCC with high expression of miR-21 (highest quartile) had impaired survival close to reaching statistical significance (P = .0630).

CONCLUSION

Our results suggest that miR-21 upregulation is involved in tumorigenesis of sinonasal carcinoma and that it is associated with poor prognosis. Thus, miR-21 could be used as a valuable prognostic biomarker.

Expression Levels and Clinical Significance of miR-21-5p, miR-let-7a, and miR-34c-5p in Laryngeal Squamous Cell Carcinoma

Objective

Altered microRNAs (miRNAs) expression has been found in many cancer types, including laryngeal squamous cell carcinoma (LSCC). The aim of this study was to determine the role and clinical value of three LSCC-related miRs, such as miR-21-5p, miR-let-7a, and miR-34c-5p in a homogeneous cohort of patients with primary LSCC treated by primary surgery.

Methods

Expression levels of miR-21-5p, miR-let-7a, and miR-34c-5p were detected in 43 pairs of LSCC and adjacent normal tissues by reverse-transcription quantitative PCR. Overall survival and disease-free survival were evaluated using the Kaplan–Meier method, and multivariate analysis was performed using the Cox proportional hazard analysis.

Results

miR-21-5p is significantly upregulated, while miR-let-7a is significantly downregulated in LSCC tumor tissues compared with the corresponding adjacent normal tissues. The downregulation of miR-34c-5p expression significantly correlated with a shorter disease-free survival and, in the multivariate analysis, low miR-34c-5p expression was associated with an increased risk of recurrence.

Conclusions

miR-21-5p, miR-let-7a, and miR-34c-5p seem to play a critical role in LSCC carcinogenesis and might have a diagnostic and prognostic clinical value. The miR-let-7a levels could have a predictive role for lymph node metastases and miR-34c-5p might be a promising biomarker of patient outcome.

miR-375 Regulates Invasion-Related Proteins Vimentin and L-Plastin

Invasion is a hallmark of advanced head and neck squamous cell carcinoma (HNSCC). We previously determined that low relative miR-375 expression was associated with poor patient prognosis. HNSCC cells with increased miR-375 expression have lower invasive properties and impaired invadopodium activity. Using stable isotope labeling with amino acids in cell culture and reverse-phase liquid chromatography mass spectrometry, we assessed the impact of miR-375 expression on protein levels in UM-SCC-1 cells. Increased miR-375 expression was associated with down-regulation of proteins involved in cellular assembly and organization, death and survival, and movement. Two invasion-associated proteins, vimentin and L-plastin, were strongly down-regulated by miR-375. Luciferase reporter assays demonstrated that high miR-375 expression reduced vimentin promoter activity, suggesting that vimentin is an indirect target of miR-375. Runt-related transcription factor 1 (RUNX1) is a potential miR-375 direct target, and its knockdown reduced vimentin and L-plastin expression. Data in The Cancer Genome Atlas HNSCC database showed a significant inverse correlation between miR-375 expression and RUNX1, vimentin, and L-plastin RNA expression. These clinical correlations validate our in vitro model findings and support a mechanism in which miR-375 suppresses RUNX1 levels, resulting in reduced vimentin and L-plastin expression. Furthermore, knockdown of RUNX1, L-plastin, and vimentin resulted in significant reductions in cell invasion in vitro, indicating the functional significance of miR-375 regulation of specific proteins involved in HNSCC invasion.

Different levels of let-7d expression modulate response of FaDu cells to irradiation and chemotherapeutics

The implication of the let-7 family in cancer development is multifaceted. The family acts as tumor suppressor miRNA although overexpression of let-7 has also been described in many types of cancer, including head and neck squamous cell carcinoma (HNSCC). The aim of this study includes whether different expression levels of let-7d has an influence on chemo- and radiosensitivity. FaDu cell line models with a gradually increased level of let-7d (models from A to E) were generated with the lentiviral system. Expression levels of pluripotency, chemo-radioresistance/apoptosis, and targets of mRNAs were analyzed by real-time reverse transcription-PCR (qRT-PCR). Radiosensitivity was analyzed using a clonogenic assay after irradiation. Response to cisplatin, 5-FU, doxorubicin, and paclitaxel was done with MTT assay. Statistically significant decrease of K-RAS (p = 0.0369) and CASPASE3 (p = 0.0342) were observed with the growing expression level of let-7d. Cisplatin, 5-FU and doxorubicin caused similar decreased of cell survival with the increase of let-7d level (p = 0.004, post-trend p = 0.046; p = 0.004, post trend p = 0.0005 and p<0.0001, post trend p = 0.0001, respectively). All models were resistant to paclitaxel, irrespective of let-7d expression levels. Only two of the generated models (A and C) were radiosensitive (p = 0.0002). Conclusion: the above results indicated that the level of let-7d expression is an important factor for cell response to irradiation and chemotherapeutics.

Salivary miR-93 and miR-200a as post-radiotherapy biomarkers in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma is the 6th most malignant tumor entity worldwide and has exhibited a 5-year mortality of approximately 50% for the last fifty years. For the therapy monitoring and successful management of this tumor entity new and easily accessible biomarkers are greatly needed. The aim of the study was to determine whether and to what extent microRNAs, a class of small regulatory RNAs, are detectable in saliva post-radiation therapy. The expression and feasibility as therapy monitoring marker of the microRNAs were analyzed by RT-qPCR in 83 saliva samples from 33 patients collected at several time points pre-, during and post-radiotherapy treatment. Ten head and neck squamous cell carcinoma- or radiation-associated microRNAs (miR-93, miR-125a, miR-142-3p, miR-200a, miR-203, miR-213, let-7a, let-7b, let-7g and let-7i) were analyzed. All were detectable to a different extent in the saliva of the patients. miR-93 and miR-200a were significantly higher expressed 12 months post-radiotherapy than at baseline (p=0.047 and p=0.036). These results point towards miR-93 and miR-200a as biomarkers for the treatment monitoring post-radiation of head and neck squamous cell carcinoma.

Downregulation of miR-377 Promotes Oral Squamous Cell Carcinoma Growth and Migration by Targeting HDAC9

microRNAs are the post-transcriptional regulators implicated in the initiation and progression of various cancer types, including oral squamous cell carcinoma (OSCC). Here, we investigated the role of miR-377 in OSCC tumorigenesis. miR-377 expression was reduced in OSCC samples and cell line (UPCI-SCC-116), and was associated with patient survival. In vitro restoration of miR-377 repressed cell growth, induced apoptosis, and reduced cell migration. We identified HDAC9 as a target of miR-377 and found miR-377 to regulate HDAC9 and its pro-apoptotic target, NR4A1/Nur77. Our findings show that miR-377 targets HDAC9 pathway in OSCC, suggesting that miR-377-HDAC9 axis may provide a novel therapeutic target for OSCC therapy.

Downregulation of miR-1 enhances tumorigenicity and invasiveness in oral squamous cell carcinomas

BACKGROUND/PURPOSE

Cumulative evidence suggest that microRNAs (miRNAs) function as biosignatures of oral squamous cell carcinomas (OSCC). However, the functional roles of miR-1 as well as its downstream targets in the regulation of tumorigenicity in OSCC remain unclear.

METHODS

miRNAs RT-PCR analysis was performed to identify miR-1 as a putative candidate on mediating invasiveness of OSCC cells. Consequently, we elucidated the tumorigenicity of OSCC cells with miR-1 downregulation or overexpression, respectively. Finally, miR-1 on OSCC tumor tissues was examined.

RESULTS

miR-1 levels were significantly downregulated in the malignant OSCC cells. Overexpression of miR-1 significantly reduced migration/invasiveness of OSCC cells. In addition, overexpression of miR-1 decreased cancer stem cells properties. Conversely, downregulation of miR-1 promotes migration and invasiveness in OSCC cells. We have shown that miR-1 is able to target Slug, suppressing their expression. Clinically, lower miR-1 expression was found in patients with advanced nodal metastasis OSCC.

CONCLUSION

miR-1 as novel biosignatures in OSCC lymph node metastatic patients, supporting the development of novel strategies for OSCC treatment.

Identification of microRNA profile specific to cancer stem-like cells directly isolated from human larynx cancer specimens

Background

Emerging evidences proposed that microRNAs are associated with regulation of distinct physio-pathological processes including development of normal stem cells and carcinogenesis. In this study we aimed to investigate microRNA profile of cancer stem-like cells (CSLCs) isolated form freshly resected larynx cancer (LCa) tissue samples.

Methods

CD133 positive (CD133⁺) stem-like cells were isolated from freshly resected LCa tumor specimens. MicroRNA profile of 12 pair of CD133⁺ and CD133⁻ cells was determined using microRNA microarray and differential expressions of selvected microRNAs were validated by quantitative real time PCR (qRT-PCR).

Results

MicroRNA profiling of CD133⁺ and CD133⁻ LCa samples with microarray revealed that miR-26b, miR-203, miR-200c, and miR-363-3p were significantly downregulated and miR-1825 was upregulated in CD133⁺ larynx CSLCs. qRT-PCR analysis in a total of 25 CD133⁺/CD133⁻ sample pairs confirmed the altered expressions of these five microRNAs. Expressions of miR-26b, miR-200c, and miR-203 were significantly correlated with miR-363-3p, miR-203, and miR-363-3p expressions, respectively. Furthermore, in silico analysis revealed that these microRNAs target both cancer and stem-cell associated signaling pathways.

Conclusions

Our results showed that certain microRNAs in CD133⁺ cells could be used as cancer stem cell markers. Based on these results, we propose that this panel of microRNAs might carry crucial roles in LCa pathogenesis through regulating stem cell properties of tumor cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2863-3) contains supplementary material, which is available to authorized users.

MicroRNA-211 Enhances the Oncogenicity of Carcinogen-Induced Oral Carcinoma by Repressing TCF12 and Increasing Antioxidant Activity

miR-211 expression in human oral squamous cell carcinoma (OSCC) has been implicated in poor patient survival. To investigate the oncogenic roles of miR-211, we generated K14-EGFP-miR-211 transgenic mice tagged with GFP. Induction of oral carcinogenesis in transgenic mice using 4-nitroquinoline 1-oxide (4NQO) resulted in more extensive and severe tongue tumorigenesis compared with control animals. We found that 4NQO and arecoline upregulated miR-211 expression in OSCC cells. In silico and experimental evidence further revealed that miR-211 directly targeted transcription factor 12 (TCF12), which mediated suppressor activities in OSCC cells and was drastically downregulated in tumor tissues. We used GeneChip analysis and bioinformatic algorithms to identify transcriptional targets of TCF12 and confirmed through reporter and ChIP assays that family with sequence similarity 213, member A (FAM213A), a peroxiredoxin-like antioxidative protein, was repressed transcriptionally by TCF12. FAM213A silencing in OSCC cells diminished oncogenic activity, reduced the ALDH1-positive cell population, and increased reactive oxygen species. TCF12 and FAM213A expression was correlated inversely in head and neck carcinoma samples according to The Cancer Genome Atlas. OSCC patients bearing tumors with high FAM213A expression tended to have worse survival. Furthermore, 4NQO treatment downregulated TCF12 and upregulated FAM213A by modulating miR-211 both in vitro and in vivo Overall, our findings develop a mouse model that recapitulates the molecular and histopathologic alterations of human OSCC pathogenesis and highlight a new miRNA-mediated oncogenic mechanism. Cancer Res; 76(16); 4872-86. ©2016 AACR.

Suberoylanilide hydroxamic acid inhibits growth of head and neck cancer cell lines by reactivation of tumor suppressor microRNAs

BACKGROUND

microRNAs negatively regulate gene expression at the post-transcriptional level. Mounting evidence shows that miR expression is deregulated in human cancers including head and neck squamous cell carcinoma (HNSCC). Epigenetically silenced tumor suppressor miRs may be re-expressed upon treatment with histone deacetylases inhibitors. Suberoylanilide Hydroxamic Acid (SAHA) is a histone deacetylase inhibitor that is currently being investigated in clinical trials for HNSCC. We hypothesized that SAHA will re-express a set of tumor suppressor miRs and enhance the efficacy of cisplatin and radiation in HNSCC.

RESULTS

In this study, miR expression profile was utilized to identify the tumor suppressor miRs that are re-expressed following SAHA treatment in HNSCC. Our data demonstrated that two tumor suppressor miRs, miR-107 and miR-138, were significantly up-regulated in CAL27 and SCC25 cell lines, following SAHA treatment. In addition to this, treatment with SAHA in a dose dependent manner significantly inhibited the cell proliferation, cell migration, and anchorage dependent clonogenic survival in CAL27 and SCC25 cell lines, respectively. Further, the expression of several oncogenes, PKCε, HIF1β, CDK6, and RhoC were down regulated in response to SAHA treatment. Additionally, we demonstrated that the combination treatment with SAHA and a chemotherapeutic drug cisplatin caused a significant reduction of cell growth compared to the single agent treatment.

CONCLUSION

Our data indicate that SAHA treatment results in reactivation of the silenced tumor suppressor miRs. Furthermore, this study emphasizes the usefulness of this drug as a novel combination therapy for HNSCC patients.

miR-372 inhibits p62 in head and neck squamous cell carcinoma in vitro and in vivo

Here we showed that exogenous miR-372 expression and knockdown of p62 (sequestosome1 or SQSTM1), both increased migration of head and neck squamous cell carcinoma (HNSCC) cells. p62 induced phase II detoxification enzyme NADPH quinone oxidoreductase 1 (NQO1), which decreased ROS levels and cell migration. Also, miR-372 decreased p62 during hypoxia, thus increasing cell migration. Levels of miR-372 and p62 inversely correlated in human HNSCC tissues. Plasma levels of miR-372 was associated with advanced tumor stage and patient mortality. Both plasma and salivary miR-372 levels were decreased after tumor resection. We conclude that miR-372 decreases p62, thus increasing ROS and motility in HNSCC cells.

Expression of stem cell-regulating miRNAs in oral cavity and oropharynx squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common tumor worldwide and is histologically heterogeneous. Studies have demonstrated the presence of stem cell markers in HNSCC, and microRNAs (miRNAs) have emerged as powerful regulators of differentiation, controlling the self-renewal of stem cells. miRNAs are non-coding RNA molecules that regulate gene expression post-transcriptionally. Many miRNAs have been described as regulators of stem cells in different types of cancer.

METHODS

We have analyzed the expression of let-7a, miR-34, miR-125b, miR-138, miR-145, miR-183, miR-200b, miR-203, and miR-205 by real-time RT-PCR (qPCR), in 35 oral cavity and oropharynx squamous cell carcinoma (SCC) samples and 10 non-neoplastic oral mucosa controls, to determine possible associations between the expression of these miRNAs and clinical and pathological features of these tumors.

RESULTS

We observed downregulation of miR-200b and miR-203 in 60.0% and 71.4% of the samples, respectively. Upregulation of miR-138 and miR-183 was observed in 50.0% of the samples. Downregulation of let-7a was associated with perineural invasion. Upregulation of miR-138, miRNA-145, and miR-205 was associated with advanced tumor stages, vascular invasion, and lymph node metastasis, respectively.

CONCLUSIONS

Our study provides evidence of the expression of miRNAs associated with stem cell regulation in oral cavity and oropharynx SCC and the association of these miRNAs with clinical and pathological features of these tumors.

Concise review: custodians of the transcriptome: how microRNAs guard stemness in squamous epithelia

At the core of every dynamic epithelium resides a population of carefully regulated stem cells ensuring its maintenance and balance. The complex mammalian epidermis is no exception to this rule. The last decade has delivered a wealth of knowledge regarding the biology of adult stem cells, but questions still remain regarding the intricate details of their function and maintenance. To help address these gaps, we turn to the small, single-stranded RNA molecules known as microRNAs. Since their discovery, microRNAs have provided us with novel insights and ground-breaking impulses to enhance our understanding of the biological sciences. Due to their unique role in post-transcriptional regulation, microRNAs are essential to cutaneous biology as well as the epidermal stem cell. By serving as buffers to balance between epithelial stemness, proliferation, and differentiation, microRNAs play essential roles in the maintenance of cutaneous stem cells and their transition out of the stem cell compartment. Following an updated overview of microRNA biology, we summarize the current knowledge of the role of microRNAs in cutaneous stem cells, focusing on three major players that have dominated the recent literature: miR-205, miR-203, and miR-125b. We then review clinical applications, discussing the potential of microRNAs as therapeutic targets in regenerative and oncological stem cell-based medicine.

MicroRNA-31 upregulation predicts increased risk of progression of oral potentially malignant disorder

OBJECTIVES

MicroRNAs (miRNAs, miRs) have shown diagnostic and prognostic potential for oral cancer but their role in oral potentially malignant disorder (OPMD) has been less investigated. We aimed to assess whether miR-21 and miR-31, two of the most relevant miRNAs in oral cancer, are useful as prognostic factors for OPMD progression.

MATERIALS AND METHODS

miR-21 and miR-31 in 20 saliva samples and 46 tissue samples from patients with OPMD (mean follow-up of 820days) were analyzed by quantitative reverse transcription PCR and in situ hybridization, respectively. The log-rank test, receiver operating characteristic curve, and Kaplan-Meier disease free survival analysis were used to assess the correlation between miRNA levels and OPMD progression.

RESULTS

Significantly increased salivary miR-21 and miR-31 expression (P=0.003 and P<0.001, respectively) was observed in patients with OPMD compared to control individuals. Patients with recurrent OPMD and/or malignant transformation exhibited a further augmented expression of miR-31, but not miR-21, in the epithelium. Furthermore, increased miR-31 expression as well as epithelial dysplasia is an independent risk factor for OPMD progression as demonstrated in Cox-proportional hazard model (HR: 8.43, P<0.05, 95%CI: 1.04 to 68.03).

CONCLUSIONS

Salivary miR-21 and miR-31 are applicable as useful OPMD screening tools. Epithelial dysplasia and miR-31 up-regulation synergistically predict the increased incidence of recurrence and/or malignant transformation in patients with OPMD. Detection of miR-31 expression is an adjuvant method for screening of high-risk OPMD.

Similar Squamous Cell Carcinoma Epithelium microRNA Expression in Never Smokers and Ever Smokers

The incidence of oral tumors in patients who never used mutagenic agents such as tobacco is increasing. In an effort to better understand these tumors we studied microRNA (miRNA) expression in tumor epithelium of never tobacco users, tumor epithelium of ever tobacco users, and nonpathological control oral epithelium. A comparison of levels among 372 miRNAs in 12 never tobacco users with oral squamous cell carcinoma (OSCC) versus 10 healthy controls was made using the reverse transcription quantitative polymerase chain reaction. A similar analysis was done with 8 ever tobacco users with OSCC. These comparisons revealed miR-10b-5p, miR-196a-5p, and miR-31-5p as enriched in the tumor epithelium in OSCC of both never and ever tobacco users. Examination of The Cancer Genome Atlas (TCGA) project miRNA data on 305 OSCCs and 30 controls revealed 100% of those miRNAs enriched in never smoker OSCCs in this patient group were also enriched in ever smoker OSCCs. Nonsupervised clustering of TCGA OSCCs was suggestive of two or four subgroups of tumors based on miRNA levels with limited evidence for differences in tobacco exposure among the groups. Results from both patient groups together stress the importance of miR196a-5p in OSCC malignancy in both never and ever smokers, and emphasize the overall similarity of miRNA expression in OSCCs in these two risk groups. It implies that there may be great similarity in etiology of OSCC in never and ever smokers and that classifying OSCC based on tobacco exposure may not be helpful in the clinic.

MiR137 is an androgen regulated repressor of an extended network of transcriptional coregulators

Androgens and the androgen receptor (AR) play crucial roles in male development and the pathogenesis and progression of prostate cancer (PCa). The AR functions as a ligand dependent transcription factor which recruits multiple enzymatically distinct epigenetic coregulators to facilitate transcriptional regulation in response to androgens. Over-expression of AR coregulators is implicated in cancer. We have shown that over-expression of KDM1A, an AR coregulator, contributes to PCa recurrence by promoting VEGFA expression. However the mechanism(s) whereby AR coregulators are increased in PCa remain poorly understood. In this study we show that the microRNA hsa-miR-137 (miR137) tumor suppressor regulates expression of an extended network of transcriptional coregulators including KDM1A/LSD1/AOF1, KDM2A/JHDM1A/FBXL11, KDM4A/JMJD2A, KDM5B JARID1B/PLU1, KDM7A/JHDM1D/PHF8, MED1/TRAP220/DRIP205 and NCoA2/SRC2/TIF2. We show that expression of miR137 is increased by androgen in LnCaP androgen PCa responsive cells and that the miR137 locus is epigenetically silenced in androgen LnCaP:C4-2 and PC3 independent PCa cells. In addition, we found that restoration of miR137 expression down-regulates expression of VEGFA, an AR target gene, which suggests a role of miR137 loss also in cancer angiogenesis. Finally we show functional inhibition of miR137 function enhanced androgen induction of PSA/KLK3 expression. Our data indicate that miR137 functions as an androgen regulated suppressor of androgen signaling by modulating expression of an extended network of transcriptional coregulators. Therefore, we propose that epigenetic silencing of miR137 is an important event in promoting androgen signaling during prostate carcinogenesis and progression.

The increase of oncogenic miRNA expression in tongue carcinogenesis of a mouse model

OBJECTIVES

This study investigated the oncogenic miRNA level in the tissue and biofluids in the Nitroquinoline 1-Oxide (4NQO)-induced mouse tongue carcinogenesis model for potential diagnostic or therapeutic application.

MATERIALS AND METHODS

The histological examination, immunohistochemistry, in situ hybridization, quantitative PCR analysis and bioinformatic algorithms were performed to unravel the signaling activation and miRNA expression in female murine samples.

RESULTS

The increase of miR-21 and miR-31 staining, and EGFR activation paralleled the severity of 4NQO-induced epithelial pathogenesis in tongue epithelium. A progressive increase of miR-21, miR-31 and miR-146a in both saliva and plasma samples was also noted. miR-31 was the earliest emerging miRNA in the saliva. The increase of plasma miR-146a, miR-184 and miR-372 was detectable early in the induction, and it was particularly eminent at the most advanced lesion state. The combined analysis of the multiple oncogenic miRNAs in the plasma signified a potent discriminative capacity between normal and pathological states. As the blockage of EGFR or AKT activation drastically reverted the miR-21, miR-31 and miR-146a expression induced by 4NQO in human oral carcinoma cell lines, the results implicated a mechanistic linkage of the oncogenic miRNAs' induction through EGFR/AKT activation.

CONCLUSIONS

In this study, we show the dysregulation of oncogenic miRNAs in murine tongue tumorigenesis, which simulates human counterparts. Increased multiple miRNAs in the biofluids may be valuable non-invasive markers in detecting oral carcinogenesis at an early stage. This animal model may also be useful for developing liquid biopsies and prevention strategies against oral carcinoma by abrogating EGFR or oncogenic miRNAs.

miR-19a and SOCS-1 expression in the differential diagnosis of laryngeal (glottic) verrucous squamous cell carcinoma

BACKGROUND

Laryngeal verrucous squamous cell carcinoma (VSCC) is a highly differentiated squamous cell carcinoma (SCC), the diagnosis of which can meet with many pitfalls: benign hyperplastic lesions and conventional SCC are the most important differential diagnoses. The microRNA miR-19a is overexpressed in many solid tumours and regulates the suppressor of cytokine signalling-1 (SOCS-1) expression.

AIMS

The main endpoints were to assess miR-19a and SOCS-1 expression in glottic VSCC, and the former's potential role in differentiating between glottic VSCC, conventional SCC and hyperplastic lesions.

METHODS

The expression of MiR-19a (by reverse transcription and quantitative real-time PCR) and SOCS-1 (by immunohistochemistry, rabbit polyclonal anti-SOCS-1 antibody) was assessed in 11 consecutive cases of glottic VSCC, 20 of papillary hyperplasia and 42 cases of conventional SCC.

RESULTS

Mean miR-19a expression was significantly higher (p = 0.000) in malignant glottic lesions (conventional SCC/VSCC) than in benign conditions. Significant differences in mean miR-19a expression also emerged between conventional SCC and papillary hyperplasia (p = 0.000), and between conventional SCC and VSCC (p = 0.03). miR-19a expression was not statistically associated with SOCS-1 immunoreactivity or immunostaining intensity in VSCC, conventional SCC or papillary hyperplasia.

CONCLUSIONS

Our preliminary outcomes suggest the utility of miR-19a in the challenging differential diagnosis of laryngeal VSCC. Although miR-19a has been found to regulate SOCS-1 expression, this evidence was not confirmed by this investigation.

MicroRNA-375 Suppresses Extracellular Matrix Degradation and Invadopodial Activity in Head and Neck Squamous Cell Carcinoma

CONTEXT

Head and neck squamous cell carcinoma (HNSCC) is a highly invasive cancer with an association with locoregional recurrence and lymph node metastasis. We have previously reported that low microRNA-375 (miR-375) expression levels correlate with poor patient survival, increased locoregional recurrence, and distant metastasis. Increasing miR-375 expression in HNSCC cell lines to levels found in normal cells results in suppressed invasive properties. HNSCC invasion is mediated in part by invadopodia-associated degradation of the extracellular matrix.

OBJECTIVE

To determine whether elevated miR-375 expression in HNSCC cell lines also affects invadopodia formation and activity.

DESIGN

For evaluation of the matrix degradation properties of the HNSCC lines, an invadopodial matrix degradation assay was used. The total protein levels of invadopodia-associated proteins were measured by Western blot analyses. Immunoprecipitation experiments were conducted to evaluate the tyrosine phosphorylation state of cortactin. Human protease arrays were used for the detection of the secreted proteases. Quantitative real time-polymerase chain reaction measurements were used to evaluate the messenger RNA (mRNA) expression of the commonly regulated proteases.

RESULTS

Increased miR-375 expression in HNSCC cells suppresses extracellular matrix degradation and reduces the number of mature invadopodia. Higher miR-375 expression does not reduce cellular levels of selected invadopodia-associated proteins, nor is tyrosine phosphorylation of cortactin altered. However, HNSCC cells with higher miR-375 expression had significant reductions in the mRNA expression levels and secreted levels of specific proteases.

CONCLUSIONS

MicroRNA-375 regulates invadopodia maturation and function potentially by suppressing the expression and secretion of proteases.

MicroRNA-34c-5p is related to recurrence in laryngeal squamous cell carcinoma

OBJECTIVES/HYPOTHESIS

Altered microRNA expression has been found in many cancer types, including laryngeal squamous cell carcinoma (LSCC). We investigated the association of LSCC-related miR-34c-5p with disease-free survival and overall survival.

STUDY DESIGN

Retrospective cohort study.

METHODS

Expression levels of miR-34c-5p were detected in 90 LSCC formalin-fixed paraffin-embedded tissues by reverse-transcription quantitative polymerase chain reaction. Overall survival and disease-free survival were evaluated using the Kaplan-Meier method, and multivariate analysis was performed using Cox proportional hazard analysis.

RESULTS

A downregulation of miR-34c-5p expression significantly correlated with worse disease-free and overall survival. In the multivariate analysis, low miR-34c-5p expression was associated with an increased risk of recurrence.

CONCLUSIONS

A downregulation of miR-34c-5p in LSCC is independently associated with unfavorable disease-free survival, suggesting that miR-34c-5p might be a promising marker for evaluating the risk of recurrences.

LEVEL OF EVIDENCE

NA.