MicroRNA-212 inhibits the metastasis of nasopharyngeal carcinoma by targeting SOX4

MiRNA signatures in nasopharyngeal carcinoma: molecular mechanisms and therapeutic perspectives

Nasopharyngeal carcinoma (NPC) is a prevalent cancerous tumor that affects the head and neck region. Recent studies have provided compelling evidence indicating the significant involvement of microRNAs (miRNAs) in the development and progression of NPC. This review aims to present a comprehensive summary of the current knowledge regarding miRNA signatures in NPC, encompassing their expression patterns, molecular mechanisms, and potential therapeutic implications. Initially, the article outlines the aberrant expression of miRNAs in NPC and elucidates their roles in tumor initiation, invasion, and metastasis. Subsequently, the underlying molecular mechanisms of miRNA-mediated regulation of NPC-associated signaling pathways are discussed. Additionally, the review highlights the potential clinical applications of miRNAs as diagnostic and prognostic biomarkers, as well as their therapeutic potential in NPC treatment. In conclusion, this review underscores the critical involvement of miRNAs in NPC pathogenesis and underscores their promise as novel therapeutic targets for combating this devastating disease.

Precision medicine in nasopharyngeal carcinoma: comprehensive review of past, present, and future prospect

Nasopharyngeal carcinoma (NPC) is an aggressive malignancy with high propensity for lymphatic spread and distant metastasis. It is prominent as an endemic malignancy in Southern China and Southeast Asia regions. Studies on NPC pathogenesis mechanism in the past decades such as through Epstein Barr Virus (EBV) infection and oncogenic molecular aberrations have explored several potential targets for therapy and diagnosis. The EBV infection introduces oncoviral proteins that consequently hyperactivate many promitotic pathways and block cell-death inducers. EBV infection is so prevalent in NPC patients such that EBV serological tests were used to diagnose and screen NPC patients. On the other hand, as the downstream effectors of oncogenic mechanisms, the promitotic pathways can potentially be exploited therapeutically. With the apparent heterogeneity and distinct molecular aberrations of NPC tumor, the focus has turned into a more personalized treatment in NPC. Herein in this comprehensive review, we depict the current status of screening, diagnosis, treatment, and prevention in NPC. Subsequently, based on the limitations on those aspects, we look at their potential improvements in moving towards the path of precision medicine. The importance of recent advances on the key molecular aberration involved in pathogenesis of NPC for precision medicine progression has also been reported in the present review. Besides, the challenge and future outlook of NPC management will also be highlighted.

SOX4 as a potential therapeutic target for pathological cardiac hypertrophy

Pathological cardiac hypertrophy can lead to heart failure, making its prevention crucial. SOX4, a SOX transcription factor, regulates tissue growth and development, although its role in pathological cardiac hypertrophy is unclear. We found that the SOX4 expression was elevated in hypertrophic hearts and angiotensin II (Ang II)-treated neonatal rat cardiomyocytes (NRCMs), and knocking down the SOX4 expression in NRCMs and mouse hearts significantly reduced the hypertrophic response. Mechanistically, SOX4 can bind to the SIRT3 promoter, inhibit SIRT3 transcription and expression, and thus affect downstream MnSOD acetylation levels, leading to abnormal increases in ROS and oxidative stress levels and promoting the occurrence of cardiac hypertrophy. In conclusion, this study identified a new role for SOX4 in regulating cardiac hypertrophy, and decreasing SOX4 expression may be a potential treatment for pathological cardiac hypertrophy.

MiR-212 value in prognosis and diagnosis of cancer and its association with patient characteristics: a systematic review and meta-analysis

Background

Delayed cancer diagnosis and inefficient cancer prognosis determination are problems faced in cancer diagnosis and treatment. MicroRNAs (miRs), especially miR-212, have shown a promise in cancer diagnosis and prognosis. Herein, we performed a systematic review and meta-analysis to assess the prognostic and diagnostic value of miR-212 level in cancer and evaluated its association with patient characteristics.

Methods

A fully electronic literature search using related keywords was performed in PubMed, Scopus, Web of Science, Embase, and ScienceDirect databases by June 6, 2021, with no time or language restriction. Meta-analysis was performed to pool survival prognosis data using hazard ratio (HR), association using odds ratio (OR), and diagnostic data using sensitivity, specificity, and diagnostic odds ratio (DOR). Sub-group analysis and meta-regression were performed as appropriate.

Results

Results of 28 studies on 1880 patients showed a poor cancer prognosis with high levels of miR-212 in pancreatic ductal adenocarcinoma (PDAC, HR = 2.451 [1.447–4.149]), and a poor cancer prognosis with low levels of miR-212 in other cancers (HR = 2.514 [2.162–2.923]). Higher alpha-fetoprotein (AFP) level and Edmondson-Steiner grade were factors associated with miR-212 low level incidence. Diagnostic odds ratio 10.688 (3.644–31.348) and SROC AUC of 0.84 confirmed high diagnostic performance of miR-212.

Conclusion

Our systematic review and meta-analysis results confirm miR-212 high value in cancer prognosis and diagnosis. High level of miR-212 showed poor prognosis in PDAC and low level of miR-212 showed poor prognosis in other cancers. in conclusion, miR-212 could be a novel potential biomarker in cancer diagnosis and prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02584-0.

MiR-212-3p functions as a tumor suppressor gene in group 3 medulloblastoma via targeting nuclear factor I/B (NFIB)

Haploinsufficiency of chromosome 17p and c-Myc amplification distinguish group 3 medulloblastomas which are associated with early metastasis, rapid recurrence, and swift mortality. Tumor suppressor genes on this locus have not been adequately characterized. We elucidated the role of miR-212-3p in the pathophysiology of group 3 tumors. First, we learned that miR-212-3p undergoes epigenetic silencing by histone modifications in group 3 tumors. Restoring its expression reduced cancer cell proliferation, migration, colony formation, and wound healing in vitro and attenuated tumor burden and improved survival in vivo. MiR-212-3p also triggered c-Myc destabilization and degradation, leading to elevated apoptosis. We then isolated an oncogenic target of miR-212-3p, i.e. NFIB, a nuclear transcription factor implicated in metastasis and recurrence in various cancers. Increased expression of NFIB was confirmed in group 3 tumors and associated with poor survival. NFIB silencing reduced cancer cell proliferation, migration, and invasion. Concurrently, reduced medullosphere formation and stem cell markers (Nanog, Oct4, Sox2, CD133) were noted. These results substantiate the tumor-suppressive role of miR-212-3p in group 3 MB and identify a novel oncogenic target implicated in metastasis and tumor recurrence.

Advances in research on microRNAs related to the invasion and metastasis of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC), which is associated with latent Epstein-Barr virus infection in most cases, is a unique epithelial malignancy arising from the nasopharyngeal mucosal lining. Accumulating evidence provides insights into the genetic and molecular aberrations that likely drive nasopharyngeal tumor development and progression. We review recent analyses of microRNAs (miRNAs), including Epstein-Barr virus-encoded miRNAs (EBV-encoded miRNAs) and dysregulated cellular miRNAs, that may be related to the metastasis of nasopharyngeal carcinoma. The studies summarized herein have greatly expanded our knowledge of the molecular biology of NPC involving miRNAs, and they may provide new biological targets for clinical diagnosis and reveal the potential of microRNA therapeutics. However, much information remains to be uncovered.

LncRNA SNHG12 regulates the miR-101-3p/CUL4B axis to mediate the proliferation, migration and invasion of non-small cell lung cancer

Mounting evidence has shown that long noncoding RNAs (lncRNAs) play critical roles in carcinogenesis and tumor progression. SNHG12 has been identified in multiple types of malignant tumors. However, the role of SNHG12 in human non-small cell lung cancer (NSCLC) is poorly characterized, and the relevant underlying mechanism remains unclear. The expression levels of SNHG12, miR-101-3p, and CUL4B in collected human NSCLC tumor tissues and NSCLC cell lines were tested via qRT-PCR. Then, NSCLC cellular proliferation, migration and invasion were determined, followed by MTT, scratch and Transwell assays. Dual-luciferase reporter assays and RNA pulldown assays were adopted to explore the target site. Moreover, western blotting was performed to detect the relevant protein expression concerning the CUL4B/PI3K/AKT pathway. This study clarified that SNHG12 knockdown significantly reduced proliferation, migration, invasion and EMT of NSCLC cells. Our data indicated that SNHG12 targeted and negatively regulated miR-101-3p, and this depletion reversed the inhibitory effect of si-SNHG12 on NSCLC cells. Furthermore, CUL4B was confirmed as a functional target of miR-101-3p, and its knockdown resulted in a strong alleviation of the NSLCL cell phenotype, which was enhanced by the silencing of miR-101-3p. Mechanistically, we found that SNHG12 regulated miR-101-3p to modulate the PI3K/AKT pathway mediated by CUL4B.These observations suggested that lncRNA SNHG12-mediated miR-101-3p downregulation regulated the malignant phenotype of NSCLC cells by targeting CUL4B through the PI3K/AKT pathway, which may present a path to novel therapeutic strategies for NSCLC therapy.

Identifying Key Genes for Nasopharyngeal Carcinoma by Prioritized Consensus Differentially Expressed Genes Caused by Aberrant Methylation

Background: Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus (EBV)-associated epithelial malignancy. Large-scale genetics or epigenetics studies of NPC have been relatively scarce and sporadic, and there are no effective targeted drugs for NPC. Integrative analysis of multiple different omics profiles has been proved to be an effective approach to shed new light on cancer.

Methods: We developed a pipeline to aggregate consensus differentially expressed genes (DEGs) from multiple expression datasets from different platforms. Integrated bioinformatics analysis of DNA methylation and gene expression was used to prioritize key genes in NPC. We explored the biological and clinical importance of key genes, combining differential co-expression analysis, network analysis of protein-protein and microRNA (miRNA)-target interactions, and pan-cancer survival analysis.

Results: We obtained 668 upregulated and 594 downregulated consensus DEGs, which enriched in the PI3K-AKT, NF-κB and immune-related pathways. In NPC, 98% of 3364 differentially methylated sites were hypermethylated. Actively expressed EBV gene EBNA1 was positively correlated with over-expressed genes coding DNA methyltransferase and Polycomb group proteins, suggesting that EBV infection may have an important role in the hypermethylation of NPC. Through integrated analysis of DNA methylation and mRNA and miRNA expression profiles, we prioritized 56 hypermethylated downregulated genes, including 7 tumor suppressor genes, and constructed a miRNA-target regulation network consisting of 12 hypermethylated miRNAs and 25 upregulated oncogenes. The promoter hypermethylation of PRKCB causing its downregulation was validated by experimental results and higher PRKCB expression was associated with longer overall survival in head-neck squamous cell carcinoma, suggesting the potential of PRKCB as a promising disease biomarker for NPC.

Conclusions: Our integrative analysis provides reliable key genes for candidate biomarkers for diagnosis and prognosis in NPC. Based on the combined evidence of promoter hypermethylation, expression up-regulation, and association with overall survival, genes such as SCUBE2, PRKCB, IKZF1, MAP4K1, and GATA6 could be promising novel diagnostic biomarkers, and miRNAs including MIR150, MIR152, and MIR34 could be candidate prognosis biomarkers.

Advances in targeted therapy mainly based on signal pathways for nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant epithelial carcinoma of the head and neck region which mainly distributes in southern China and Southeast Asia and has a crucial association with the Epstein-Barr virus. Based on epidemiological data, both incidence and mortality of NPC have significantly declined in recent decades grounded on the improvement of living standard and medical level in an endemic region, in particular, with the clinical use of individualized chemotherapy and intensity-modulated radiotherapy (IMRT) which profoundly contributes to the cure rate of NPC patients. To tackle the challenges including local recurrence and distant metastasis in the current NPC treatment, we discussed the implication of using targeted therapy against critical molecules in various signal pathways, and how they synergize with chemoradiotherapy in the NPC treatment. Combination treatment including targeted therapy and IMRT or concurrent chemoradiotherapy is presumably to be future options, which may reduce radiation or chemotherapy toxicities and open new avenues for the improvement of the expected functional outcome for patients with advanced NPC.

Suppression of Sox4 protects against myocardial ischemic injury by reduction of cardiac apoptosis in mice

Sox4 participates in the progression of embryo development and regulation of apoptosis in tumors. However, the effect and mechanism of Sox4 in myocardial infarction (MI) remains unclear. Therefore, we aimed at examining the role and molecular mechanism of Sox4 in the process of cardiomyocytes apoptosis during MI. The expression of Sox4 were obviously increased both in MI mice and in neonatal mouse cardiomyocytes treated with H₂ O₂ . Overexpression of Sox4 promoted cardiomyocyte apoptosis with or without H₂ O₂ , whereas knocking down of Sox4 alleviated H₂ O₂ -induced apoptosis in cardiomyocytes. Furthermore, silencing Sox4 by AAV-9 carried short hairpin RNA targeting Sox4 (AAV-9-sh-Sox4) markedly decreased cardiac infarct area, imprfoved cardiac dysfunction, and reversed apoptosis in MI mice. Mechanistically, there is a potential Sox4-binding site in the promoter region of Bim, and forced expression of Sox4 significantly promoted Bim expression in cultured cardiomyocytes with or without H₂ O₂ , whereas knocking down of Sox4 inhibited the expression of Bim. Further studies showed that silencing Bim attenuated Sox4-induced apoptosis in cardiomyocytes, indicating that Sox4 promoted cardiomyocytes apoptosis through regulation of Bim expression, which can be used as a potential therapeutic target for MI.

MiR-34c downregulation leads to SOX4 overexpression and cisplatin resistance in nasopharyngeal carcinoma

Background

A major cause of disease-related death in nasopharyngeal carcinoma (NPC) is the development of distant metastasis (DM) despite combination chemoradiotherapy treatment. We previously identified and validated a four microRNA (miRNA) signature that is prognostic for DM. In this study, characterization of a key component of this signature, miR-34c, revealed its role in chemotherapy resistance.

Methods

Two hundred forty-six NPC patient biopsy samples were subject to comprehensive miRNA profiling and immunohistochemistry (IHC). Two human normal nasopharyngeal cell lines (immortalized; NP69 and NP460), as well as the NPC cell line C666–1, were used for miR-34c gain-of-function and loss-of-function experiments. Signaling pathways were assessed using quantitative real-time PCR (qRT-PCR) and Western blot. Cell viability was measured using the ATPlite assay.

Results

MiR-34c was downregulated in NPC patient samples, and confirmed in vitro to directly target SOX4, a master regulator of epithelial-to-mesenchymal transition (EMT). MiR-34c downregulation triggered EMT-representative changes in NP69 and NP460 whereby Snail, ZEB1, CDH2, and SOX2 were upregulated, while Claudin-1 and CDH1 were downregulated. Phenotypically, inhibition of miR-34c led to cisplatin resistance, whereas miR-34c over-expression sensitized NPC cells to cisplatin. TGFβ1 decreased miR-34c and increased SOX4 expression in vitro. The TGFβ receptor 1 inhibitor SB431542 reduced SOX4 expression and increased cisplatin sensitivity. Finally, IHC revealed that lower SOX4 expression was associated with improved overall survival in chemotherapy-treated NPC patients.

Conclusion

miR-34c is downregulated in NPC. Repression of miR-34c was shown to increase SOX4 expression, which leads to cisplatin resistance, while TGFβ1 was found to repress miR-34c expression. Taken together, our study demonstrates that inhibition of the TGFβ1 pathway could be a strategy to restore cisplatin sensitivity in NPC.

MiR-30e-5p inhibits the migration and invasion of nasopharyngeal carcinoma via regulating the expression of MTA1

The study explored the effect of miR-30e-5p on nasopharyngeal carcinoma (NPC). MiR-30e-5p levels in NPC cancer and adjacent normal samples, in metastatic and non-metastatic cancer samples of NPC, and in NP69 cell and five NPC cell lines were determined by quantitative real-time polymerase chain reaction (qRT-PCR). The relationship between miR-30e-5p and MTA1 was confirmed by dual-luciferase reporter assay, Western blot and qRT-PCR. The viability, migration and invasion of 5-8F and 6-10B cells were determined by CCK-8, scratch test and transwell assays, respectively. The levels of migration-related proteins (vimentin and Snail) and invasion-related proteins (MMP2 and MMP3) in NPC cells were detected by Western blot. The results showed that low expression of miR-30e-5p was associated with HNSC cancer, NPC, metastasis of NPC and NPC cell lines. Overexpressed miR-30e-5p in HNSC cancer and NPC was predictive of a better prognosis of patients. In addition, the viability, migration and invasion were reduced by up-regulating miR-30e-5p in 5-8F cells, but promoted by down-regulated miR-30e-5p in 6-10B cells. MiR-30e-5p reversed the migration and invasion of NPC cells regulated by MTA1, and inhibited migration and invasion of NPC cells via regulating MTA1 expression.

MicroRNA-212 suppresses cell proliferation in nasopharyngeal carcinoma by targeting ELF3

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy of the head and neck that is prevalent in China. The present study investigated the molecular mechanisms of microRNA-212 (miR-212) and E74-like factor 3 (ELF3) in NPC cell lines and tissues. Using reverse transcription-quantitative PCR, the present study identified that miR-212 expression was downregulated in NPC cell lines and tissues. Furthermore, an elevated expression level of miR-212 was revealed to inhibit NPC cell proliferation, as determined using a cell counting kit-8 assay in vitro. ELF3 was identified as a direct target of miR-212 in NPC cells by a luciferase reporter assay. Additionally, the expression levels of miR-212 and ELF3 were negatively correlated in NPC tissues. The expression levels of ELF3 and miR-212 were associated with metastasis and TNM stage in patients with NPC. In summary, the present study indicated that miR-212 was downregulated in NPC and suppressed cell proliferation. This suggested that the miR-212/ELF3 axis may serve as a novel target for the diagnosis and treatment of NPC.

Downregulation of CLDN6 inhibits cell proliferation, migration, and invasion via regulating EGFR/AKT/mTOR signalling pathway in hepatocellular carcinoma

Accumulating evidence showed that the claudin-6 (CLDN6) expression was abnormal in many cancers, while its expression and biological functions in hepatocellular carcinoma (HCC) is still unclear. The present study demonstrated that CLDN6 was upregulated in HCC tissues compared with tumour-adjacent tissues. CLDN6 silencing was significantly inhibited proliferation, migration, and invasion of HepG2 cells. Meanwhile, downregulation of CLDN6 remarkably inhibited the activation of EGFR/AKT/mTOR signalling pathway. Interestingly, the effect of CLDN6 overexpression on HepG2 cell proliferation and invasion could be inhibited by EGFR/AKT/mTOR signalling pathway inhibitor (AG1478). SIGNIFICANCE OF THE STUDY: These findings suggested that CLDN6 may act as an oncogene in HCC and improve HepG2 cell proliferation, migration, and invasion may via EGFR/AKT/mTOR signalling pathway.

The functions and targets of miR-212 as a potential biomarker of cancer diagnosis and therapy

Cancer is a major health problem worldwide. An increasing number of researchers are studying the diagnosis, therapy and mechanisms underlying the development and progression of cancer. The study of noncoding RNA has attracted a lot of attention in recent years. It was found that frequent alterations of miRNA expression not only have various functions in cancer but also that miRNAs can act as clinical markers of diagnosis, stage and progression of cancer. MiR-212 is an important example of miRNAs involved in cancer. According to recent studies, miR-212 may serve as an oncogene or tumour suppressor by influencing different targets or pathways during the oncogenesis and the development and metastasis of cancer. Its deregulation may serve as a marker for the diagnosis or prognosis of cancer. In addition, it was recently reported that miR-212 was related to the sensitivity or resistance of cancer cells to chemotherapy or radiotherapy. Here, we summarize the current understanding of miR-212 functions in cancer by describing the relevant signalling pathways and targets. The role of miR-212 as a biomarker and its therapeutic potential in cancer is also described. The aim of this review was to identify new methods for the diagnosis and treatment of human cancers.

Prognostic Value of miRNAs in Head and Neck Cancers: A Comprehensive Systematic and Meta-Analysis

Head and Neck Cancer (HNC) is the sixth most common type of cancer across the globe, with more than 300,000 deaths each year, globally. However, there are currently no standardised molecular markers that assist in determining HNC prognosis. The literature for this systematic review and meta-analysis were sourced from multiple bibliographic databases. This review followed PRISMA guidelines. The Hazard Ratio (HR) was selected as the effect size metric to independently assess overall survival (OS), disease-free survival (DFS), and prognosis. Subgroup analysis was performed for individual highly represented miRNA. A total of 6843 patients across 50 studies were included in the systematic review and 34 studies were included in the meta-analysis. Studies across 12 countries were assessed, with China representing 36.7% of all included studies. The analysis of the survival endpoints of OS and DFS were conducted separately, with the overall pooled effect size (HR) for each being 1.825 (95% CI 1.527–2.181; p < 0.05) and 2.596 (95% CI 1.917–3.515; p < 0.05), respectively. Subgroup analysis was conducted for impact of miR-21, 200b, 155, 18a, 34c-5p, 125b, 20a and 375 on OS, and miR-21 and 34a on DFS. The pooled results were found to be statistically significant for both OS and DFS. The meta-analysis indicated that miRNA alterations can account for an 82.5% decrease in OS probability and a 159.6% decrease in DFS probability. These results indicate that miRNAs have potential clinical value as prognostic biomarkers in HNC, with miR-21, 125b, 34c-5p and 18a, in particular, showing great potential as prognostic molecular markers. Further large scale cohort studies focusing on these miRNAs are recommended to verify the clinical utility of these markers individually and/or in combination.

Isoliquiritigenin suppresses the proliferation and induced apoptosis via miR-32/LATS2/Wnt in nasopharyngeal carcinoma

Nasopharyngeal Carcinoma is limited by the various severe side-effects and surgery is rarely performed. Iosliquiritigenin has a series of biological activities, such as antiviral, anti-free radical and antitumor. However, the role and underlying mechanism of isoliquiritigenin in nasopharyngeal carcinoma have not been understood yet. Herein, the results revealed that isoliquiritigenin could inhibit cell proliferation in nasopharyngeal carcinoma cell lines, including C666-1 and CNE2, in both Cell Counting Kit-8 (CCK-8) and 5-Ethynyl-2'-deoxyuridine (EdU) assay. In addition, isoliquiritigenin promoted nasopharyngeal carcinoma cell apoptosis, with the up-regulations of Bax, Caspase-3 and Caspase-9 and the down-regulation of Bcl-2. Meanwhile, isoliquiritigenin suppressed nasopharyngeal carcinoma cells migration and invasion with the down-regulation of matrix metalloproteinases (MMP)-2 and MMP-9. Furthermore, the expression of miR-32 was up-regulated in the nasopharyngeal carcinoma tissues, while isoliquiritigenin could significantly down-regulate the expression of miR-32. And over-expression of miR-32 promoted the nasopharyngeal carcinoma cells growth, migration and invasion, and suppressed apoptosis. However, isoliquiritigenin treatment dramatically inhibited the effect of miR-32. Besides, luciferase reporter assay confirmed that large tumor suppressor 2 (LATS2) was a direct target of miR-32. And isoliquiritigenin increased the expression of LATS2, while silencing of LATS2 promoted the nasopharyngeal carcinoma cells growth. Moreover, western blotting discovered that isoliquiritigenin inhibited nasopharyngeal carcinoma cells growth via Wnt signaling pathway. Finally, CNE2 cells transplanted xenografts tumor model in nude mice were performed and it suggested that isoliquiritigenin could inhibit the development of xenografts nude mice, along with the decrease of tumor volume and the expression of miR-32 and LATS2. Overall, isoliquiritigenin was confirmed to be a potent anti-nasopharyngeal carcinoma compound both in vitro and in vivo, and accomplished by regulation of miR-32/LATS2/Wnt.

miR-212 regulated by HIF-1α promotes the progression of pancreatic cancer

MicroRNA-212 (miR-212) is dysregulated in numerous tissues and cancer types and serves a role in the progression of human cancer. However, the function and mechanism of miR-212 in the development of pancreatic ductal adenocarcinoma (PDAC) remain unknown, particularly in a hypoxic microenvironment. In the present study, miR-212 expression was observed to be significantly upregulated in PDAC tissues compared with normal tissues. Clinical data analysis indicated that miR-212 was positively associated with a large tumor size, Tumor-Node-Metastasis stage, lymph node metastasis and vessel invasion, and influenced the overall survival time. Notably, there was a positive association between the expression of hypoxia-inducible factor-1α (HIF-1α) and miR-212 in vivo and in vitro in hypoxic conditions. Mechanistically, HIF-1α bound directly to a hypoxia response element in the miR-212 promoter region and activated miR-212 expression in PDAC cells. Collectively, these results demonstrated that HIF-1α positively regulated miR-212 expression and resulted in PDAC progression.

miR-140-5p inhibits cell proliferation and invasion in colorectal carcinoma by targeting SOX4

MicroRNAs (miRNAs) have been reported to influence the occurrence and development of colorectal carcinoma (CRC). In the current research, we explored miR-140-5p function in CRC. In addition, the molecular mechanisms of miR-140-5p/SOX4 axis for CRC were investigated. The miR-140-5p and SOX4 expression levels were evaluated via RT-qPCR or western blot analysis. The MTT and Transwell assay assessed cell proliferation and invasion. Luciferase assay confirmed that miR-140-5p directly targeted SOX4. Moreover, the results showed that miR-140-5p expression was obviously declined in CRC. The low expression of miR-140-5p was related to tumor stage or metastasis. The miR-140-5p overexpression suppressed cell proliferation and invasion in CRC. Moreover, miR-140-5p was identified to directly target SOX4 and the SOX4 expression was increased in CRC. In addition, the high expression of SOX4 promoted cell proliferation and invasion in CRC. The inhibiting effect of miR-140-5p on SOX4 was identified for CRC, and it inhibited the proliferation and invasion. The novel miR-140-5p/SOX4 axis may provide a new therapy for CRC.

The regulatory network of nasopharyngeal carcinoma metastasis with a focus on EBV, lncRNAs and miRNAs

Metastasis of nasopharyngeal carcinoma (NPC) remains a main cause of death for NPC patients even though great advances have been made in therapeutic approaches. An in-depth study into the molecular mechanisms of NPC metastasis will help us combat NPC. Epstein-Barr virus (EBV) infection is an evident feature of nonkeratinizing NPC and is strongly associated with tumor metastasis. Recently, long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) have become a hot topic of research due to their epigenetic regulatory roles in NPC metastasis. The EBV products, lncRNAs and miRNAs can target each other and share several common signaling pathways, which form an interconnected, complex molecular regulatory network. In this review, we discuss the features of this regulatory network and summarize the molecular mechanisms of NPC metastasis, focusing on EBV, lncRNAs and miRNAs with updated knowledge.

Knockdown of BRCC3 exerts an anti‑tumor effect on cervical cancer in vitro

Cervical cancer is a serious malignancy that affects the health of females. In the present study, the association between breast cancer type 1 susceptibility protein/breast cancer type 2 susceptibility protein-containing complex subunit 3 (BRCC3) and cervical cancer was investigated. Reverse transcription-quantitative polymerase chain reaction and western blotting were performed to determine BRCC3 mRNA and protein expression levels in cervical cancer tissues and cells, in addition to the expression levels of proteins associated with the epithelial-mesenchymal transition (EMT) process in HeLa and SiHa cells. Cell Counting Kit-8, Transwell and wound healing assays were performed to determine the cell viability, invasion and migration abilities of cervical cancer cells, respectively. The results of the present study revealed that BRCC3 expression was significantly increased in cervical cancer tissues, which was also revealed to be associated with the clinical stages and pathological grades of cervical cancer exhibited by patients, in addition to the survival time. Furthermore, BRCC3 expression levels were enhanced in HeLa, SiHa and C-33A cervical cancer cells. BRCC3 interference in HeLa and SiHa cells was revealed to suppress cell viability, invasion and migration abilities via upregulation of E-cadherin expression levels and downregulation of Vimentin, matrix metalloproteinase (MMP)-2, MMP-9, snail family transcriptional repressor (Snai)1 and Snai2 expression levels. In conclusion, the expression levels of BRCC3 were revealed to be increased in cervical cancer tissues, which were positively associated with clinical features of cervical cancer. Furthermore, BRCC3 interference inhibited the cell viability, invasion and migration abilities of HeLa and SiHa cells via regulation of EMT progression and expression levels of Snai family members. In addition, the results of the present study suggested that BRCC3 represents an oncogene associated with cervical cancer, and may also represent a novel therapeutic biomarker for the diagnosis, treatment and prognosis of patients with cervical cancer.

MicroRNA‑122 acts as tumor suppressor by targeting TRIM29 and blocking the activity of PI3K/AKT signaling in nasopharyngeal carcinoma in vitro

Nasopharyngeal carcinoma (NPC) is endemic in the southern provinces of China and Southeast Asia. It has been reported that microRNA-122 (miR-122) and tripartite motif-containing protein 29 (TRIM29) serve important roles in many types of tumor. The present study aimed to evaluate the expression of miR-122 and TRIM29, and their clinical significance in NPC, and to examine the associated molecular mechanisms. It was observed that low expression of miR-122 and high expression of TRIM29 led to a low overall survival rate in patients with NPC, which was associated with tumor-node-metastasis (TNM) stage and distant metastasis of NPC. Low expression of miR-122 was correlated reciprocally with high expression of TRIM29 in NPC tissues, and the two were aggravated by radiation treatment in NPC cell lines. Through Cell Counting kit-8 and Transwell assays, miR-122 was demonstrated to be able to inhibit the proliferation, migration and invasion of NPC cells. Through reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analyses, the expression of metastasis-associated genes, including E-cadherin, metastatic tumor antigen 1, matrix metalloproteinase-2 and metalloproteinase inhibitor 2 were demonstrated to be regulated by miR-122 in NPC cells. Additionally, through a luciferase assay, RT-qPCR and western blot analysis, it was demonstrated that TRIM29 may be a direct target of miR-122. In addition, it was noted that miR-122 decreased the expression of phosphorylated (p) phosphatidylinositol 3-kinase (PI3K) and p-RAC-α serine/threonine-protein kinase (AKT). Collectively, the results of the present study demonstrated that miR-122 may exert its tumor suppressive role by targeting TRIM29 and inhibiting the activity of PI3K/AKT signaling. It was indicated that miR-122 and TRIM29 may be developed as biomarkers of NPC, and possible molecular targets for the prevention of metastasis in patients with NPC.

MicroRNA-212 Targets Mitogen-Activated Protein Kinase 1 to Inhibit Proliferation and Invasion of Prostate Cancer Cells

Prostate cancer (PCa) is the second most commonly diagnosed malignancy and the fifth leading cause of cancer-related deaths in males worldwide. MicroRNAs (miRNAs) may serve as important regulators in PCa occurrence and development. Therefore, understanding the expression and functions of PCa-related miRNAs may be beneficial for the identification of novel therapeutic methods for patients with PCa. In this study, miRNA-212 (miR-212) was evidently downregulated in PCa tissues and several PCa cell lines. Functional assays showed that the resumption of miR-212 expression attenuated cell proliferation and invasion and increased the apoptosis of PCa. In addition, mitogen-activated protein kinase 1 (MAPK1), a well-known oncogene, was identified as a novel target of miR-212 in PCa, as confirmed by bioinformatics, luciferase reporter assay, qRT-PCR, and Western blot analysis. Furthermore, MAPK1 expression was upregulated in PCa tissues and inversely correlated with miR-212 expression. Rescue experiments also demonstrated that restored MAPK1 expression reversed the tumor-suppressing effects of miR-212 on PCa cell proliferation, invasion, and apoptosis. In conclusion, miR-212 may exert tumor-suppressing roles in PCa by regulating MAPK1 and could be a novel therapeutic target for treatment of patients with this malignancy.

MicroRNA-212 activates hepatic stellate cells and promotes liver fibrosis via targeting SMAD7

There has been an increasing number of researches about microRNAs (miRNAs) in the progression of liver fibrosis from the point of their comprehensive functions in regulating the activation of hepatic stellate cells (HSCs). Among them, it has been reported that miR-212 is up-regulated in activated rat primary HSCs. However, its mechanism has not been determined yet. Here, we confirmed that the level of miR-212-3p was up-regulated in livers of carbon tetrachloride (CCl₄)-treated mice compared with the normal control, which is a classical model of chronically damaged fibrotic liver. In vitro, we demonstrated that TGF-β, a master fibrogenic cytokine, could induce the level of miR-212. In turn, overexpression of miR-212 could induce the activation marker of HSC including α-smooth muscle actin (α-SMA) and collagens by activating TGF-β signaling pathway. Furthermore, SMAD7, a dominant suppressor of TGF-β pathway, was identified as a direct target of miR-212-3p. Our results indicate that miR-212-3p facilitates the activation of HSCs and TGF-β pathway by targeting SMAD7, highlighting that it can be served as a novel biomarker or therapeutic target for liver fibrosis.