MiR-34a suppresses HNSCC growth through modulating cell cycle arrest and senescence

Immune Escape Strategies in Head and Neck Cancer: Evade, Resist, Inhibit, Recruit

Head and neck cancers (HNCs) arise from the mucosal lining of the aerodigestive tract and are often associated with alcohol use, tobacco use, and/or human papillomavirus (HPV) infection. Over 600,000 new cases of HNC are diagnosed each year, making it the sixth most common cancer worldwide. Historically, treatments have included surgery, radiation, and chemotherapy, and while these treatments are still the backbone of current therapy, several immunotherapies have recently been approved by the Food and Drug Administration (FDA) for use in HNC. The role of the immune system in tumorigenesis and cancer progression has been explored since the early 20th century, eventually coalescing into the current three-phase model of cancer immunoediting. During each of the three phases-elimination, equilibrium, and escape-cancer cells develop and utilize multiple strategies to either reach or remain in the final phase, escape, at which point the tumor is able to grow and metastasize with little to no detrimental interference from the immune system. In this review, we summarize the many strategies used by HNC to escape the immune system, which include ways to evade immune detection, resist immune cell attacks, inhibit immune cell functions, and recruit pro-tumor immune cells.

MiR-34a functions as a tumor suppressor in oral cancer through the inhibition of the Axl/Akt/GSK-3β pathway

Background/purpose

Oral cancer is a prevalent malignancy affecting men globally. This study aimed to investigate the regulatory role of miR-34a in oral cancer cells through the Axl/Akt/glycogen synthase kinase-3β (GSK-3β) pathway and its impact on cellular malignancy.

Materials and methods

We examined the effects of miR-34a overexpression on the malignancy of oral cancer cells. Multiple oral cancer cell lines were assessed to determine the correlation between endogenous miR-34a and Axl levels. Transfection experiments with miR-34a were conducted to analyze its influence on Axl mRNA and protein expression. Luciferase reporter assays were performed to investigate miR-34a's modulation of Axl gene transcription. Manipulation of miR-34a expression was utilized to demonstrate its regulatory effects on oral cancer cells through the Axl/Akt/GSK-3β pathway.

Results

Overexpression of miR-34a significantly suppressed the malignancy of oral cancer cells. We observed an inverse correlation between endogenous miR-34a and Axl levels across multiple oral cancer cell lines. Transfection of miR-34a resulted in decreased Axl mRNA and protein expression, and luciferase reporter assays confirmed miR-34a-mediated modulation of Axl gene transcription. The study revealed regulatory effects of miR-34a on oral cancer cells through the Axl/Akt/GSK-3β pathway, leading to alterations in downstream target genes involved in cellular proliferation and tumorigenesis.

Conclusion

Our findings highlight the significance of the miR-34a/Axl/Akt/GSK-3β signaling axis in modulating the malignancy of oral cancer cells. Targeting miR-34a may hold therapeutic potential in oral cancer treatment, as manipulating its expression can attenuate the aggressive behavior of oral cancer cells via the Axl/Akt/GSK-3β pathway.

p53/MicroRNA-34 axis in cancer and beyond

Cancer is serious endangers human life. After a long period of research and accumulation, people's understanding of cancer and the corresponding treatment methods are constantly developing. p53 is an important tumor suppressor gene. With the more in-depth understanding of the structure and function of p53, the more importance of this tumor suppressor gene is realized in the process of inhibiting tumor formation. MicroRNAs (miRNAs) are important regulatory molecules with a length of about 22nucleotides (nt), which belong to non-coding RNA and play an important role in the occurrence and development of tumors. miR-34 is currently considered to be a master regulator of tumor suppression. The positive feedback regulatory network formed by p53 and miR-34 can inhibit the growth and metastasis of tumor cells and inhibit tumor stem cells. This review focuses on the latest progress of p53/miR-34 regulatory network, and discusses its application in tumor diagnosis and treatment.

Deciphering the endometrial immune landscape of RIF during the window of implantation from cellular senescence by integrated bioinformatics analysis and machine learning

Recurrent implantation failure (RIF) is an extremely thorny issue in in-vitro fertilization (IVF)-embryo transfer (ET). However, its intricate etiology and pathological mechanisms are still unclear. Nowadays, there has been extensive interest in cellular senescence in RIF, and its involvement in endometrial immune characteristics during the window of implantation (WOI) has captured scholars' growing concerns. Therefore, this study aims to probe into the pathological mechanism of RIF from cellular senescence and investigate the correlation between cellular senescence and endometrial immune characteristics during WOI based on bioinformatics combined with machine learning strategy, so as to elucidate the underlying pathological mechanisms of RIF and to explore novel treatment strategies for RIF. Firstly, the gene sets of GSE26787 and GSE111974 from the Gene Expression Omnibus (GEO) database were included for the weighted gene correlation network analysis (WGCNA), from which we concluded that the genes of the core module were closely related to cell fate decision and immune regulation. Subsequently, we identified 25 cellular senescence-associated differentially expressed genes (DEGs) in RIF by intersecting DEGs with cellular senescence-associated genes from the Cell Senescence (CellAge) database. Moreover, functional enrichment analysis was conducted to further reveal the specific molecular mechanisms by which these molecules regulate cellular senescence and immune pathways. Then, eight signature genes were determined by the machine learning method of support vector machine-recursive feature elimination (SVM-RFE), random forest (RF), and artificial neural network (ANN), comprising LATS1, EHF, DUSP16, ADCK5, PATZ1, DEK, MAP2K1, and ETS2, which were also validated in the testing gene set (GSE106602). Furthermore, distinct immune microenvironment abnormalities in the RIF endometrium during WOI were comprehensively explored and validated in GSE106602, including infiltrating immunocytes, immune function, and the expression profiling of human leukocyte antigen (HLA) genes and immune checkpoint genes. Moreover, the correlation between the eight signature genes with the endometrial immune landscape of RIF was also evaluated. After that, two distinct subtypes with significantly distinct immune infiltration characteristics were identified by consensus clustering analysis based on the eight signature genes. Finally, a "KEGG pathway-RIF signature genes-immune landscape" association network was constructed to intuitively uncover their connection. In conclusion, this study demonstrated that cellular senescence might play a pushing role in the pathological mechanism of RIF, which might be closely related to its impact on the immune microenvironment during the WOI phase. The exploration of the molecular mechanism of cellular senescence in RIF is expected to bring new breakthroughs for disease diagnosis and treatment strategies.

Promising Biomarkers in Head and Neck Cancer: The Most Clinically Important miRNAs

Head and neck cancers (HNCs) comprise a heterogeneous group of tumors that extend from the oral cavity to the upper gastrointestinal tract. The principal etiologic factors for oral tumors include tobacco smoking and alcohol consumption, while human papillomavirus (HPV) infections have been accused of a high incidence of pharyngeal tumors. Accordingly, HPV detection has been extensively used to categorize carcinomas of the head and neck. The diverse nature of HNC highlights the necessity for novel, sensitive, and precise biomarkers for the prompt diagnosis of the disease, its successful monitoring, and the timely prognosis of patient clinical outcomes. In this context, the identification of certain microRNAs (miRNAs) and/or the detection of alterations in their expression patterns, in a variety of somatic fluids and tissues, could serve as valuable biomarkers for precision oncology. In the present review, we summarize some of the most frequently studied miRNAs (including miR-21, -375, -99, -34a, -200, -31, -125a/b, -196a/b, -9, -181a, -155, -146a, -23a, -16, -29, and let-7), their role as biomarkers, and their implication in HNC pathogenesis. Moreover, we designate the potential of given miRNAs and miRNA signatures as novel diagnostic and prognostic tools for successful patient stratification. Finally, we discuss the currently ongoing clinical trials that aim to identify the diagnostic, prognostic, or therapeutic utility of miRNAs in HNC.

Emerging Role of Non-Coding RNAs in Senescence

Senescence is defined as a gradual weakening of functional features of a living organism. Cellular senescence is a process that is principally aimed to remove undesirable cells by prompting tissue remodeling. This process is also regarded as a defense mechanism induced by cellular damage. In the course of oncogenesis, senescence can limit tumor progression. However, senescence participates in the pathoetiology of several disorders such as fibrotic disorders, vascular disorders, diabetes, renal disorders and sarcopenia. Recent studies have revealed contribution of different classes of non-coding RNAs in the cellular senescence. Long non-coding RNAs, microRNAs and circular RNAs are three classes of these transcripts whose contributions in this process have been more investigated. In the current review, we summarize the available literature on the impact of these transcripts in the cellular senescence.

High density lipoprotein nanoparticle as delivery system for radio-sensitising miRNA: An investigation in 2D/3D head and neck cancer models

Radiotherapy is one of the main treatment options for head and neck cancer patients. However, its clinical efficacy is hindered by both radiation induced side effects and radio-resistance. Radio-sensitising approaches with acceptable toxicity are being actively investigated. Among these, RNA therapeutics have great potentials as radio-sensitisers owing to their ability to target pathways specific to radio-resistance. However, their clinical translation is challenging due to delivery issues. Herein, we report the application of high-density lipoprotein nanoparticle (HDL NPs) as a biocompatible delivery system for a well-established radio-sensitising RNA, miR-34a. A simple/fast microfluidic based technique was used to prepare miR-34a-HDL NPs. Profiling of the radiation response in the UM-SCC-1 head and neck cancer cell line confirmed reduced metabolic activity and increased radiation induced apoptosis upon treatment with miR-34a-HDL NPs. The radio-sensitising properties of miR-34a-HDL NPs were further confirmed in a more biologically relevant co-culture spheroid model of head and neck cancer. Increased apoptotic activity and disrupted cell cycle were induced by miR-34a delivered by HDL NPs. The enhanced radio-biologic effects observed in both 2D and 3D models confirmed the utility of HDL NPs as an efficient delivery system for radio-sensitising RNA.

Epigenetic Regulation of Glycosylation

Expression of glycosylation-related genes (or glycogenes) is strictly regulated by transcription factors and epigenetic processes, both in normal and in pathological conditions. In fact, glycosylation is an essential mechanism through which proteins and lipids are modified to perform a variety of biological events, to adapt to environment, and to interact with microorganisms.Many glycogenes with a role in normal development are epigenetically regulated. Essential studies were performed in the brain, where expression of glycogenes like MGAT5B, B4GALNT1, and ST8Sia1 are under the control of histone modifications, and in the immune system, where expression of FUT7 is regulated by both DNA methylation and histone modifications. At present, epigenetic regulation of glycosylation is still poorly described under physiological conditions, since the majority of the studies were focused on cancer. In fact, virtually all types of cancers display aberrant glycosylation, because of both genetic and epigenetic modifications on glycogenes. This is also true for many other diseases, such as inflammatory bowel disease, diabetes, systemic lupus erythematosus, IgA nephropathy, multiple sclerosis, and cardiovascular diseases.A deeper knowledge in epigenetic regulation of glycogenes is essential, since research in this field could be helpful in finding novel and personalized therapeutics.

Epigenetic Regulation of Glycosylation in Cancer and Other Diseases

In the last few decades, the newly emerging field of epigenetic regulation of glycosylation acquired more importance because it is unraveling physiological and pathological mechanisms related to glycan functions. Glycosylation is a complex process in which proteins and lipids are modified by the attachment of monosaccharides. The main actors in this kind of modification are the glycoenzymes, which are translated from glycosylation-related genes (or glycogenes). The expression of glycogenes is regulated by transcription factors and epigenetic mechanisms (mainly DNA methylation, histone acetylation and noncoding RNAs). This review focuses only on these last ones, in relation to cancer and other diseases, such as inflammatory bowel disease and IgA1 nephropathy. In fact, it is clear that a deeper knowledge in the fine-tuning of glycogenes is essential for acquiring new insights in the glycan field, especially if this could be useful for finding novel and personalized therapeutics.

Down-regulation of the tumor suppressor miR-34a contributes to head and neck cancer by up-regulating the MET oncogene and modulating tumor immune evasion

BACKGROUND

MicroRNAs (miRs) have been shown to play an important role in tumorigenesis, including in head and neck squamous cell carcinoma (HNSCC). The miR-34 family is thought to play a role in tumor suppression, but the exact mechanism of their action in HNSCC is not well understood. Moreover, the impact of chromosomal changes and mutation status on miR-34a expression remains unknown.

METHODS

Differential expression of miR-34a, MET, and genomic alterations were assessed in the Cancer Genome Atlas (TCGA) datasets as well as in primary HNSCC and adjacent normal tissue. The biological functions of miR-34a in HNSCC were investigated in samples derived from primary human tumors and HNSCC cell lines. The expression of MET was evaluated using immunohistochemistry, and the molecular interaction of miR-34a and MET were demonstrated by RNA pulldown, RNA immunoprecipitation, luciferase reporter assay, and rescue experiments. Lastly, locked nucleic acid (LNA) miRs in mouse xenograft models were used to evaluate the clinical relevance of miR-34a in HNSCC tumor growth and modulation of the tumor microenvironment in vivo.

RESULTS

Chromosome arm 1p loss and P53 mutations are both associated with lower levels of miR-34a. In HNSCC, miR-34a acts as a tumor suppressor and physically interacts with and functionally targets the proto-oncogene MET. Our studies found that miR-34a suppresses HNSCC carcinogenesis, at least in part, by downregulating MET, consequently inhibiting HNSCC proliferation. Consistent with these findings, administration of LNA-miR-34a in an in vivo model of HNSCC leads to diminished HNSCC cell proliferation and tumor burden in vitro and in vivo, represses expression of genes involved in epithelial-mesenchymal transition, and negates the oncogenic effect of MET in mouse tumors. Consistently, LNA-miR-34a induced a decreased number of immunosuppressive PDL1-expressing tumor-associated macrophages in the tumor microenvironment. In HNSCC patient samples, higher levels of miR-34a are significantly associated with a higher frequency of Th1 cells and CD8 naïve T cells.

CONCLUSIONS

Our results demonstrate that miR-34a directly targets MET and maintains anti-tumor immune activity. We propose miR-34a as a potential new therapeutic approach for HNSCC.

Saturated Fatty Acids Promote Hepatocytic Senecence through Regulation of miR-34a/Cyclin-Dependent Kinase 6

SCOPE

Obesity increases intracellular lipid accumulation in hepatocytes, which can induce non-alcoholic fatty liver disease (NAFLD). With progression of NAFLD, a sizable fraction of patients develop non-alcoholic steatohepatitis (NASH), eventually leading to cirrhosis and hepatocellular carcinoma (HCC). The mechanism involved in obesity-induced NAFLD remains unclear. Free fatty acids and high-fat diets, which induce hepatocyte senescence, are major risk factors for NAFLD. Therefore in this study, the mechanism of lipotoxicity-induced hepatocyte senescence is investigated.

METHODS AND RESULTS

The mice are fed a high-fat diet (HFD) and BNL CL.2 cells are treated with palmitate acid (PA) to establish in vivo and in vitro models of lipotoxicity, respectively. SA-β-gal staining is used to analyze the positively stained senescent hepatocytes. The results show that both PA and HFD induce cellular senescence. Real-time-PCR quantitative analysis reveals that miR-34a is significantly upregulated in the liver tissues of the HFD mice and in the PA-treated BNL CL.2 cells. Western blotting analysis shows that cyclin-dependent kinase inhibitor 1 (CDKN1, also known as p21) is upregulated, while cyclin-dependent kinase 6 (CDK6) is downregulated. Further investigation of the mechanism reveals that CDK6 is a target of miR-34a, which binds to the 3' UTR of CDK6 and inhibits its expression.

CONCLUSION

The findings reveal that miR-34a is upregulated in a high-fat environment in the liver, and induces hepatocyte senescence by targeting CDK6. The miR-34a-CDK6 signaling axis may promote NAFLD development in a high-fat environment and therefore represents a potential target for NAFLD therapy.

Sweet Control: MicroRNA Regulation of the Glycome

Glycosylation is a sophisticated informational system that controls specific biological functions at the cellular and organismal level. Dysregulation of glycosylation may underlie some of the most complex and common diseases of the modern era. In the past 5 years, microRNAs have come to the forefront as a critical regulator of the glycome. Herein, we review the current literature on miRNA regulation of glycosylation and how this work may point to a new way to identify the biological importance of glycosylation enzymes.

Senescence Induction by Combined Ionizing Radiation and DNA Damage Response Inhibitors in Head and Neck Squamous Cell Carcinoma Cells

DNA damage response inhibitors (DDRi) may selectively enhance the inactivation of tumor cells in combination with ionizing radiation (IR). The induction of senescence may be the key mechanism of tumor cell inactivation in this combinatorial treatment. In the current study the effect of combined IR with DDRi on the induction of senescence was studied in head and neck squamous cell carcinoma (HNSCC) cells with different human papilloma virus (HPV) status. The integrity of homologous recombination (HR) was assessed in two HPV positive, two HPV negative HNSCC, and two healthy fibroblast cell cultures. Cells were treated with the DDRi CC-115 (DNA-dependent protein kinase, DNA-pK; dual mammalian target of rapamycin, mTor), VE-822 (ATR; ataxia telangiectasia and Rad3-related kinase), and AZD0156 (ATM; ataxia telangiectasia mutated kinase) combined with IR. Effects on senescence, apoptosis, necrosis, and cell cycle were analyzed by flow cytometry. The fibroblast cell lines generally tolerated IR or combined treatment better than the tumor cell lines. The ATM and ATR inhibitors were effectively inducing senescence when combined with IR. The DNA-PK inhibitor was not an important inductor of senescence. HPV status and HR activity had a limited influence on the efficacy of DDRi. Induction of senescence and necrosis varied individually among the cell lines due to molecular heterogeneity and the involvement of DNA damage response pathways in senescence induction.

Multifunctional Roles of miR-34a in Cancer: A Review with the Emphasis on Head and Neck Squamous Cell Carcinoma and Thyroid Cancer with Clinical Implications

MiR-34a belongs to the class of small non-coding regulatory RNAs and functions as a tumor suppressor. Under physiological conditions, miR-34a has an inhibitory effect on all processes related to cell proliferation by targeting many proto-oncogenes and silencing them on the post-transcriptional level. However, deregulation of miR-34a was shown to play important roles in tumorigenesis and processes associated with cancer progression, such as tumor-associated epithelial-mesenchymal transition, invasion, and metastasis. Moreover, further understanding of miR-34a molecular mechanisms in cancer are indispensable for the development of effective diagnosis and treatments. In this review, we summarized the current knowledge on miR-34a functions in human disease with an emphasis on its regulation and dysregulation, its role in human cancer, specifically head and neck squamous carcinoma and thyroid cancer, and emerging role as a disease diagnostic and prognostic biomarker and the novel therapeutic target in oncology.

Downregulation of MicroRNA-551b Correlates With Dissemination of Human Oral Squamous Cell Carcinoma

PURPOSE

Altered expression of microRNAs contributes to invasion and metastasis of many human cancers; however, the importance of microRNAs in head and neck cancers remains to be elucidated. In this study, we examined whether altered microRNA (miR)-551b expression correlated with invasive phenotypes of human oral squamous cell carcinoma (OSCC) in vivo and in vitro.

MATERIALS AND METHODS

Real-time polymerase chain reaction was used to detect the expression level of miR-551b in 71 OSCC tissues with lymph node metastasis and 50 nonmetastatic OSCC tissues. We also constructed miR-551b mimic-transfected cell lines HN4 and HN12. The effects of overexpressing miR-551b on the proliferation, migration, and invasion of OSCC cells were examined using Cell Counting Kit 8 (Dojindo, Kumamoto, Japan), plate clone formation, wound healing, and Transwell invasion experiments (Corning, Corning, NY). The association between clinical pathologic parameters and the expression level of miR-551b was analyzed using Kaplan-Meier survival analysis.

RESULTS

The expression of miR-551b measured 0.33 ± 0.11 in the 71 OSCC tissues with lymph node metastasis versus 0.54 ± 0.06 in the 50 tissues with non-lymph node metastasis (P = .021). Regarding OSCC patients, the expression of miR-551b negatively correlated with patients' overall survival (P = .035). The ectopic expression of miR-551b inhibited the invasion and migration of OSCC cells.

CONCLUSIONS

This is the first report showing that reduced miR-551b expression may be an event leading to OSCC invasion and metastasis.

MicroRNA-139 is a predictor of prostate cancer recurrence and inhibits growth and migration of prostate cancer cells through cell cycle arrest and targeting IGF1R and AXL

BACKGROUND

We previously identified a panel of five microRNAs (miRNAs) associated with biochemical recurrence and metastasis following prostatectomy from prostate cancer patients using next-generation sequencing-based whole miRNome sequencing and quantitative polymerase chain reaction-based validation analysis. In this study, we examined the mechanism of action of miR-139-5p, one of the downregulated miRNAs identified in the panel.

METHODS

Using a cohort of 585 patients treated with radical prostatectomy, we examined the prognostic significance of miR-139 (dichotomized around the median) using the Kaplan-Meier method and Cox proportional hazard models. We validated these results using The Cancer Genome Atlas (TCGA) data. We created cell lines that overexpressed miR-139 to confirm its targets as well as examine pathways through which miR-139 may function using cell-based assays.

RESULTS

Low miR-139 expression was significantly associated with a variety of prognostic factors in prostate cancer, including Gleason score, pathologic stage, margin positivity, and lymph node status. MiR-139 expression was associated with prognosis: the cumulative incidence of biochemical recurrence and metastasis were significantly lower among patients with high miR-139 expression (P = .0004 and .038, respectively). Validation in the TCGA data set showed a significant association between dichotomized miR-139 expression and biochemical recurrence (odds ratio, 0.52; 95% confidence interval, 0.33-0.82). Overexpression of miR-139 in prostate cancer cells led to a significant reduction in cell proliferation and migration compared with control cells, with cells arrested in G2 of cell cycle. IGF1R and AXL were identified as potential targets of miR-139 based on multiple miRNA-binding sites in 3'-untranslated regions of both the genes and their association with prostate cancer growth pathways. Luciferase assays verified AXL and IGF1R as direct targets of miR-139. Furthermore, immunoblotting of prostate cancer cells demonstrated IGF1R and AXL protein expression were inhibited by miR-139 treatment, which was reversed by the addition of miR-139 antagomir. Examination of the molecular mechanism of growth inhibition by miR-139 revealed the downregulation of activated AKT and cyclin D1, with upregulation of the CDK inhibitor p21.

CONCLUSIONS

miR-139 is associated with improved prognosis in patients with localized prostate cancer, which may be mediated through downregulation of IGF1R and/or AXL and associated signaling pathway components.

14-3-3ζ targeting induced senescence in Hep-2 laryngeal cancer cell through deneddylation of Cullin1 in the Skp1-Cullin-F-box protein complex

Objectives

Despite of the aberrant expression of 14‐3‐3ζ in head and neck squamous cell carcinoma (HNSCC), little is known about the role of 14‐3‐3ζ in the regulation of senescence in HNSCC. This study was performed to investigate whether 14‐3‐3ζ is implicated in senescence evasion of Hep‐2 laryngeal cancer cells.

Methods

The expression of 14‐3‐3ζ was suppressed using RNA interference strategy. Senescence induction was determined by senescence‐associated β‐galactosidase staining and the numbers of promyelocytic leukaemia nuclear body. Real‐time PCR, western blotting and immunohistochemistry were applied for the expression of corresponding proteins. Xenograft experiment was performed to show in vivo effect of 14‐3‐3ζ silencing on tumour growth.

Results

14‐3‐3ζ silencing significantly induced senescence phenotypes via 27 accumulations. Subsequently, we demonstrated that p27 accumulation is linked to inactivation of SCF^Skp2 complex activity, probably due to the deneddylation of cullin‐1 (Cul‐1) as follows. (a) Neddylated Cul‐1 is decreased by 14‐3‐3ζ silencing. (b) Blocking neddylation using MLN4924 reproduces senescence phenotypes. (c) Knockdown of CSN5, which functions as a deneddylase, was shown to restore the senescence phenotypes induced by 14‐3‐3ζ depletion. Finally, we demonstrated that 14‐3‐3ζ depletion effectively hindered the proliferation of Hep‐2 cells implanted into nude mice.

Conclusion

14‐3‐3ζ negatively regulates senescence in Hep‐2 cells, suggesting that 14‐3‐3ζ targeting may serve to suppress the expansion of laryngeal cancer via induction of senescence through the Cul‐1/SCF^Skp2/p27 axis.

MicroRNA-transcription factor network analysis reveals miRNAs cooperatively suppress RORA in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) represents over 90% of oral cancer incidence, while its mechanisms of tumorigenesis remain poorly characterized. In this study, we applied RNA-seq and microRNA-seq methodologies in four pairs of cancer and adjacent normal tissues to profile the contribution of miRNAs to tumorigenesis-altered functional pathways by constructing a comprehensive miRNA-mediated mRNA regulatory network. There were 213 differentially expressed (DE) miRNAs and 2172 DE mRNAs with the involvement of negative miRNA-mRNA interactions identified by at least two pairs of cancerous tissues. GO analysis revealed that the upregulated microRNAs significantly contributed to a global down-regulation of a number of transcription factors (TFs) in OSCC. Among the negative regulatory networks between the selected miRNAs (133) and TFs (167), circadian rhythm genes (RORA, RORB, RORC, and CLOCK) simultaneously regulated by multiple microRNAs were of particular interest. For instance, RORA transcript was predicted to be targeted by 25 co-upregulated miRNAs, of which, miR-503-5p, miR-450b-5p, miR-27a-3p, miR-181a-5p and miR-183-5p were further validated to directly target RORA, resulting in a stronger effect on RORA suppression together. In addition, we showed that the mRNA and protein expression levels of RORα were significantly decreased in most OSCC samples, associated with advanced clinical stage and poor prognosis. RORα significantly suppressed the proliferation of OSCC cells in vitro and in vivo. Attenuated RORα decreased p53 protein expression and suppressed p53 phosphorylation activity. Altogether, our results strongly suggest the importance of the role of miRNAs in regulating the activity of circadian rhythm-related TFs network during OSCC tumorigenesis, and provide further clues to understand the clinical link between circadian rhythm and cancer therapy.

Clinical significance of miR-34a expression in thyroid diseases - an 18F-FDG PET-CT study

Purpose

To evaluate the possible roles of miR-34a expression in thyroid lesions, to unravel the correlation between fluorodeoxyglucose (FDG) uptake and miR-34a expression and moreover, to discover the underlying mechanisms by which miR-34a regulates FDG avidity.

Methods

We retrospectively reviewed 75 patients with pathology-confirmed thyroid diseases who underwent ¹⁸F-FDG positron emission tomography/computed tomography (PET/CT) within 3 months before undergoing thyroid surgery and miR-34a analysis from June 2012 to July 2017. ¹⁸F-FDG uptake of thyroid lesions was also analyzed semiquantitatively using maximum standardized uptake value (SUVmax). The association between miR-34a expression and clinicopathological variables (age, sex, TNM stage, histopathology, lesion numbers, location and ¹⁸F-FDG avidity) was investigated. When there were multiple lesions in thyroid bed, only the one with the highest ¹⁸F-FDG uptake was analyzed. Next, we inhibited the miR-34a expression in TPC-1 cells and detected the expression of glucose transporter 1 (GLUT1) mRNA and protein.

Results

In the patients cohort, miR-34a was upregulated in those with malignant thyroid diseases compared with benign lesions. The expression of miR-34a was associated with tumor stages, histopathological types and SUVmax. There was an inverse relationship between miR-34a expression and SUVmax in patients with thyroid diseases (Spearman correlation coefficient = −0.553, P < 0.0001). With an SUVmax of 4.3 as the threshold, sensitivity and specificity of the prediction of miR-34a expression (low or high) were 70% and 94.3%, respectively. The area under the receiver operating characteristic curve was 0.843 (95% confidence interval: 0.749, 0.936; P = 0.001). Inhibiting miR-34a in TPC-1 cells significantly increased GLUT1 mRNA and protein expression.

Conclusion

miR-34a expression was upregulated in thyroid lesions, negatively correlated with SUVmax and can be predicted by FDG SUVmax. In addition, miR-34a may regulate FDG avidity via targeting GLUT1.

Simultaneous overexpression of miR-126 and miR-34a induces a superior antitumor efficacy in pancreatic adenocarcinoma

Background

Pancreatic adenocarcinoma (PAC) is one of the most fatal cancers due to its high degree of malignancy, increasing incidence, high mortality, and unsatisfactory treatment efficacy. Evidence has suggested that numerous microRNAs (miRNAs), including miR-126 and miR-34a, have potent tumor-suppressing effects on PAC, implicating a possible application of miRNA in tumor therapy. However, the therapeutic effect of a single miRNA on pancreatic cancer is limited.

Methods

We simultaneously delivered miR-126 and miR-34a into PAC cells by a carcinoembryonic antigen promoter-driven oncolytic adenovirus (AdCEAp-miR126/34a), and examined the antitumor efficacy of the therapeutic system in in vitro and in vivo experiments.

Results

In vitro cytological experiments found that the expression levels of miR-126 and miR-34a were specifically increased in the AdCEAp-miR126/34a-infected PAC cells, and the antitumor efficacy was enhanced in aspects of cancer cell viability, migration, invasion, and apoptosis, by synergistically combining the antitumor effects of overexpressed miR-126 and miR-34a and the oncolytic effect of viral replication specifically in PAC cells. The expression levels of miR-126 target genes (vascular endothelial growth factor-A and SOX2) and miR-34a target genes (cyclin D1, E2F1, and Bcl-2) were markedly decreased in the PAC cells after being infected with AdCEAp-miR126/34a. Notable suppression of the therapeutic system on tumor growth was also proven in established PAC xenograft tumor models in nude mice, which demonstrated that the combination of miR-126 and miR-34a exerts more effective antitumor outcomes than a single miRNA.

Conclusion

The therapeutic system co-expressing miR-126 and miR-34a mediated by oncolytic adenovirus is a promising system for PAC target therapy.