The tumor suppressor miR-124 inhibits cell proliferation by targeting STAT3 and functions as a prognostic marker for postoperative NSCLC patients

Prospective study: expression levels of microRNA-7-3p and its target STAT3 in head and neck cancer

BACKGROUND

Head and neck cancer (HNC) is the seventh most prevalent type of cancer in the globe, and it encompasses a wide range of tumors that affect the oral, facial and neck region. Despite breakthroughs in treatment strategies, patients survival has not increased substantially in the last few decades. Therefore, there is need for quick and reliable biomarkers and therapeutic targets for the treatment of HNC. Interestingly, microRNAs (miRNAs) are a small non-coding RNAs (ncRNAs) that have a role in the post-transcriptional regulation of gene expression. Thus, the aim of the study is to evaluate the role of miR-7-3p in the HNC and normal tissues.

METHODS

A total of 25 HNC and normal tissues were collected from the Department of Oral and Maxillofacial Surgery, Saveetha Dental College and Hospitals. Bioinformatic tool (TargetScan) was used to predict the target for miR-7-3p. The tissue samples were processed for Hematoxylin and Eosin staining and following that total RNA was extracted and analyzed for expression studies using RT-qPCR.

RESULTS

The bioinformatic analysis of the current study have revealed that STAT3 is a direct target for miR-7-3p. The histopathological examination showed damaged epithelial cells and keratin pool formation was observed in HNC tissue. Our results have also revealed that the miR-7-3p levels were significantly reduced and STAT3 levels were significantly higher in the HNC tissues when compared to the normal tissues.

CONCLUSIONS

MiR-7-3p can be used as a prognostic, diagnostic biomarker and therapeutic target for the treatment of HNC.

Use of recombinant microRNAs as antimetabolites to inhibit human non-small cell lung cancer

During the development of therapeutic microRNAs (miRNAs or miRs), it is essential to define their pharmacological actions. Rather, miRNA research and therapy mainly use miRNA mimics synthesized in vitro. After experimental screening of unique recombinant miRNAs produced in vivo, three lead antiproliferative miRNAs against human NSCLC cells, miR-22-3p, miR-9-5p, and miR-218-5p, were revealed to target folate metabolism by bioinformatic analyses. Recombinant miR-22-3p, miR-9-5p, and miR-218-5p were shown to regulate key folate metabolic enzymes to inhibit folate metabolism and subsequently alter amino acid metabolome in NSCLC A549 and H1975 cells. Isotope tracing studies further confirmed the disruption of one-carbon transfer from serine to folate metabolites by all three miRNAs, inhibition of glucose uptake by miR-22-3p, and reduction of serine biosynthesis from glucose by miR-9-5p and -218-5p in NSCLC cells. With greater activities to interrupt NSCLC cell respiration, glycolysis, and colony formation than miR-9-5p and -218-5p, recombinant miR-22-3p was effective to reduce tumor growth in two NSCLC patient-derived xenograft mouse models without causing any toxicity. These results establish a common antifolate mechanism and differential actions on glucose uptake and metabolism for three lead anticancer miRNAs as well as antitumor efficacy for miR-22-3p nanomedicine, which shall provide insight into developing antimetabolite RNA therapies.

Hydrogen-rich saline alleviates cardiomyocyte apoptosis by reducing expression of calpain1 via miR-124-3p

AIMS

Molecular hydrogen has been exhibited a protective function in heart diseases. Our previous study demonstrated that hydrogen-rich saline (HRS) could scavenge free radicals selectively and alleviate the inflammatory response in the myocardial ischaemia/reperfusion (I/R) injury, but the underlying mechanism has not been fully clarified.

METHODS AND RESULTS

Adult (10 weeks) C57BL/6 male mice and neonatal rat cardiomyocytes were used to establish I/R and hypoxia/reoxygenation (H/R) injury models. I/R and H/R models were treated with HRS to classify the mechanisms of cardioproctective function. In this study, we found that miR-124-3p was significantly decreased in both I/R and H/R models, while it was partially ameliorated by HRS pretreatment. HRS treatment also alleviated ischaemia-induced apoptotic cell death and increased cell viability during I/R process, whereas silencing expression of miR-124-3p abolished this protective effect. In addition, we identified calpain1 as a direct target of miR-124-3p, and up-regulation of miR-124-3 produced both activity and expression of calpain1. It was also found that compared with the HRS group, overexpression of calpain1 increased caspase-3 activities, promoted cleaved-caspase3 and Bax protein expressions, and correspondingly decreased Bcl-2, further reducing cell viability. These results illustrated that calpain1 overexpression attenuated protective effect of HRS on cardiomyocytes in H/R model.

CONCLUSIONS

The present study showed a protective effect of HRS on I/R injury, which may be associated with miR-124-3p-calpain1 signalling pathway.

MicroRNA in lung cancer-a novel potential way for early diagnosis and therapy

Lung cancer is the most common cause of cancer-related deaths in the world. One of the reasons of poor prognosis and high mortality of lung cancer patients is the diagnosis of the disease in its advanced stage. Despite innovative diagnostic methods and multiple completed and ongoing clinical trials aiming at therapy improvement, no significant increase in patients' long-term survival has been noted over last decades. Patients would certainly benefit from early detection of lung cancer. Therefore, it is crucial to find new biomarkers that can help predict outcomes and tumor responses in order to maximize therapy effectiveness and avoid over- or under-treating patients with lung cancer. Nowadays, scientists' attention is mainly dedicated to so-called liquid biopsy, which is fully non-invasive and easily available method based on simple blood draw. Among common liquid biopsy elements, circulating tumor nucleic acids are worth mentioning. Epigenetic biomarkers, particularly miRNA expression, have several distinct features that make them promising prognostic markers. In this review, we described miRNA's involvement in tumorigenesis and present it as a predictor of cancer development and progression, potential indicator of treatment efficacy, and most importantly promising therapeutic target.

miR-124 as a Liquid Biopsy Prognostic Biomarker in Small Extracellular Vesicles from NSCLC Patients

Despite advances in non-small cell lung cancer (NSCLC) research, this is still the most common cancer type that has been diagnosed up to date. microRNAs have emerged as useful clinical biomarkers in both tissue and liquid biopsy. However, there are no reliable predictive biomarkers for clinical use. We evaluated the preclinical use of seven candidate miRNAs previously identified by our group. We collected a total of 120 prospective samples from 88 NSCLC patients. miRNA levels were analyzed via qRT-PCR from tissue and blood samples. miR-124 gene target prediction was performed using RNA sequencing data from our group and interrogating data from 2952 NSCLC patients from two public databases. We found higher levels of all seven miRNAs in tissue compared to plasma samples, except for miR-124. Our findings indicate that levels of miR-124, both free-circulating and within exosomes, are increased throughout the progression of the disease, suggesting its potential as a marker of disease progression in both advanced and early stages. Our bioinformatics approach identified KPNA4 and SPOCK1 as potential miR-124 targets in NSCLC. miR-124 levels can be used to identify early-stage NSCLC patients at higher risk of relapse.

Novel Histopathological Biomarkers in Prostate Cancer: Implications and Perspectives

Prostate cancer (PCa) is the second most frequently diagnosed cancer in men. Despite the significant progress in cancer diagnosis and treatment over the last few years, the approach to disease detection and therapy still does not include histopathological biomarkers. The dissemination of PCa is strictly related to the creation of a premetastatic niche, which can be detected by altered levels of specific biomarkers. To date, the risk factors for biochemical recurrence include lymph node status, prostate-specific antigen (PSA), PSA density (PSAD), body mass index (BMI), pathological Gleason score, seminal vesicle invasion, extraprostatic extension, and intraductal carcinoma. In the future, biomarkers might represent another prognostic factor, as discussed in many studies. In this review, we focus on histopathological biomarkers (particularly CD169 macrophages, neuropilin-1, cofilin-1, interleukin-17, signal transducer and activator of transcription protein 3 (STAT3), LIM domain kinase 1 (LIMK1), CD15, AMACR, prostate-specific membrane antigen (PSMA), Appl1, Sortilin, Syndecan-1, and p63) and their potential application in decision making regarding the prognosis and treatment of PCa patients. We refer to studies that found a correlation between the levels of biomarkers and tumor characteristics as well as clinical outcomes. We also hypothesize about the potential use of histopathological markers as a target for novel immunotherapeutic drugs or targeted radionuclide therapy, which may be used as adjuvant therapy in the future.

Tumor Suppressive Effects of miR-124 and Its Function in Neuronal Development

MicroRNA-124 (miR-124) is strongly expressed in neurons, and its expression increases as neurons mature. Through DNA methylation in the miR-124 promoter region and adsorption of miR-124 by non-coding RNAs, miR-124 expression is known to be reduced in many cancer cells, especially with high malignancy. Recently, numerous studies have focused on miR-124 due to its promising tumor-suppressive effects; however, the overview of their results is unclear. We surveyed the tumor-suppressive effect of miR-124 in glial cell lineage cancers, which are the most frequently reported cancer types involving miR-124, and in lung, colon, liver, stomach, and breast cancers, which are the top five causes of cancer death. Reportedly, miR-124 not only inhibits proliferation and accelerates apoptosis, but also comprehensively suppresses tumor malignant transformation. Moreover, we found that miR-124 exerts its anti-tumor effects by regulating a wide range of target genes, most notably STAT3 and EZH2. In addition, when compared to the original role of miR-124 in neuronal development, we found that the miR-124 target genes that contribute to neuronal maturation share similarities with genes that cause cancer cell metastasis and epithelial-mesenchymal transition. We believe that the two apparently unrelated fields, cancer and neuronal development, can bring new discoveries to each other through the study of miR-124.

Tumor-Derived Exosomes Enriched by miRNA-124 Promote Anti-tumor Immune Response in CT-26 Tumor-Bearing Mice

Exosomes have been introduced as a new alternative delivery system for the transmission of small molecules. Tumor-derived exosomes (TEXs) not only contain tumor-associated antigens to stimulate antitumor immune responses but also act as natural carriers of microRNAs. The aim of the current study was to evaluate the efficacy of miR-124-3p-enriched TEX (TEXomiR) as cell-free vaccine in the induction of antitumor immune responses in a mouse model of colorectal cancer. Briefly, the exosomes were isolated from cultured CT-26 cell line, and modified calcium chloride method was used to deliver miR-124-3p mimic into the exosomes. We used a CT-26-induced BALB/c mouse model of colorectal cancer and analyzed the effect of TEXomiR on survival, tumor size, spleen and tumor-infiltrated lymphocytes, and splenocyte proliferation. Furthermore, intra-tumor regulatory T cells, cytotoxic activity of the splenocytes, and cytokine secretion was also evaluated to describe the anti-tumor immune response. When the tumor size reached 100 mm³, the mice were injected with TEXomiR, TEX, and/or phosphate-buffered saline (PBS) subcutaneously three times with 3-day interval, and then tumor size was monitored every 2 days. The in vitro results indicated that TEXs could efficiently deliver functional miR-124-3p mimic. The in vivo evaluation in tumor-bearing mice showed that treatment with TEXomiR can elicit a stronger anti-tumor immune response than unloaded TEX and PBS. Significant tumor growth inhibition and increased median survival time was achieved in tumor-bearing mice treated with TEXomiR. A significant decrease in CD4/CD8 and Treg/CD8 ratio in tumor tissue was demonstrated. Moreover, increased cytotoxicity and proliferation of splenocytes in the TEXomiR group compared to the TEX and PBS groups were identified. Taken together, our data demonstrated that tumor-derived exosomes efficiently deliver miR-124-3p mimic, and TEXomiR promotes anti-tumor immune responses.

Forsythoside A protects against lipopolysaccharide-induced acute lung injury through up-regulating microRNA-124

Acute lung injury (ALI) is a life-threatening disease without effective pharmacotherapies, so far. Forsythia suspensa is frequently used in the treatment of lung infection in traditional Chinese medicine. In search for natural anti-inflammatory components, the activity and the underlying mechanism of Forsythoside A (FA) from Forsythia suspensa were explored. In the present paper, BALB/c mice and murine RAW 264.7 cells were stimulated by LPS to establish inflammation models. Data showed that FA inhibited the production of TNF-α and IL-6 and the activation of STAT3 in LPS-stimulated RAW 264.7 cells. Additionally, FA increased the expression level of microRNA-124 (miR-124). Furthermore, the inhibitory effect of FA on STAT3 was counteracted by the treatment of miR-124 inhibitor. Critically, FA ameliorated LPS-induced ALI pathological damage, the increase in lung water content and inflammatory cytokine, cells infiltration and activation of the STAT3 signaling pathway in BALB/c mice. Meanwhile, FA up-regulated the expression of miR-124 in lungs, while administration with miR-124 inhibitor attenuated the protective effects of FA. Our results indicated that FA alleviates LPS-induced inflammation through up-regulating miR-124 in vitro and in vivo. These findings indicate the potential of FA and miR-124 in the treatment of ALI.

Regulatory Mechanism of MicroRNA-30b on Neonatal Hypoxic-Ischemic Encephalopathy (HIE)

OBJECTIVE

This study is to investigate the role of microRNA (miR)-30b in the pathogenesis of hypoxic-ischemic encephalopathy (HIE) in neonates.

METHODS

Totally 26 cases of neonatal HIE were included in this study. The protein expression levels of CD26P and PAI-1 were detected with ELISA. Serum levels of miR-30b and PAI-1 mRNA was measured by quantitative real-time PCR. Human brain microvascular endothelial cells (HBMECs) were cultured under hypoxic condition, and the intracellular expression levels of miR-30b and PAI-1 were evaluated. Dual-luciferase reporter assay was performed to confirm the interaction between miR-30b and PAI-1.

RESULTS

Compared with the control group, both the mRNA and protein expression levels of PAI-1 in the serum were up-regulated in the neonates with HIE, together with up-regulated serum CD26P levels. However, the serum expression level of miR-30b was down-regulated in neonatal HIE. In hypoxia-induced HBMECs, the mRNA and protein expression levels of PAI-1 were significantly up-regulated, while the miR-30b expression level was significantly down-regulated. Dual-luciferase reporter assay showed that PAI-1 was the direct target of miR-30b.

CONCLUSION

Neonatal HIE is accompanied with abnormal platelet activation, significantly up-regulated serum PAI-1 expression levels, and down-regulated miR-30b expression. MiR-30b might regulate the disease pathogenesis and immune responses via modulating PAI-1.

hUCB-MSC derived exosomal miR-124 promotes rat liver regeneration after partial hepatectomy via downregulating Foxg1

Liver regeneration after partial hepatectomy (PH) is a complex and well-orchestrated process involving multiple factors such as cytokines, growth factors, and signaling pathways. MicroRNAs (miRNAs) participate in various biological processes including liver regeneration after PH. In the current study, we investigated the expression and function of human umbilical cord blood mesenchymal stem cell (hUCB-MSC) derived exosomal miRNAs on liver regeneration using a rat PH model. We found that hUCB-MSC derived exosomes promoted rat liver regeneration and ameliorated liver injury after PH. MicroRNA microarray was performed to identify the differentially expressed miRNAs in hUCB-MSC derived exosomes involving in liver regeneration after PH. We demonstrated that hUCB-MSC derived exosomal miR-124 could promote liver regeneration and prevent against liver injury after PH in rats. Inhibition of miR-124 abrogated the protective role of hUCB-MSC derived exosome in rat liver regeneration after PH. In addition, we identified that transcription factor Foxg1 was a direct target of miR-124 and miR-124 promoted rat liver cell proliferation via suppressing Foxg1 expression. Furthermore, we demonstrated that hUCB-MSC derived exosomal miR-124 enhanced liver regeneration via inhibiting Foxg1 in rats after PH. In summary, our findings suggest that hUCB-MSC-derived exosomal miR-124 could promote rat liver regeneration after PH via downregulating Foxg1.

Overexpression of microRNA-124-5p sensitizes non-small cell lung cancer cells to treatment with 5-fluorouracil via AEG-1 regulation

Chemotherapeutic resistance represents a major obstacle for the treatment of patients with non-small cell lung cancer (NSCLC); however, the associated molecular mechanisms underpinning the development of resistance remain poorly characterized. In the current study, 5-fluorouracil (5-FU)-resistant A549 cells (A549/5-FU) were generated from A549 cells. Reverse transcription-quantitative PCR and western blotting were used to detect microRNA(miR)-124-5p and astrocyte elevated gene 1 (AEG-1) expression levels in cells and tumor tissues. In addition, the cytotoxic effect of 5-FU on the cells was determined using the Cell Counting Kit-8 assay, and the Dual-luciferase reporter assay was used to validate AEG-1 as a target gene of miR-124-5p. Transfection with a miR-124-5p mimic enhanced inhibition of cell viability induced by 5-FU in A549/5-FU cells, whereas miR-124-5p inhibitor transfection partially reversed 5-FU-induced cell viability inhibition in A549 and H1299 cells. A decrease in miR-124-5p expression level was observed in A549/5-FU cells compared with the parental A549 cells. Furthermore, AEG-1 was predicted as a target gene of miR-124-5p, and its expression was increased in A549/5-FU cells compared with A549 cells. Additionally, the upregulation of miR-124-5p was associated with lower expression levels of AEG-1 in A549/5-FU cells, compared with parental A549 cells. Moreover, the Dual-luciferase reporter assay confirmed the ability of miR-124-5p to bind directly to the 3'-untranslated region of AEG-1 mRNA. Notably, the overexpression of AEG-1 reversed the ability of the miR-124-5p mimic to increase the sensitivity of A549/5-FU cells to 5-FU treatment. Additionally, a significant negative correlation between miR-124-5p expression and AEG-1 mRNA levels was detected in 40 pairs of NSCLC tissues and their corresponding adjacent paracancerous tissues. The results of the present study indicated that miR-124-5p may regulate the chemotherapeutic sensitivity of NSCLC cells, and may therefore represent a promising biomarker or therapeutic target for patients with NSCLC.

A SNP in the 3'UTR of the porcine IGF-1 gene interacts with miR-new14 to affect IGF-1 expression, proliferation and apoptosis of PK-15 cells

The kidney of miniature pigs has been considered the most likely potential kidney source for patients needing kidney transplantation. Insulin-like growth factor 1 (IGF-1) is involved in regulating the growth of miniature pigs and inducing growth of kidneys. There are evidences showing that the SNPs in the 3'UTR of a gene may affect the gene expression by affecting the binding to a miRNA target site. In this study, one SNP (rs34142920) was screened in the IGF-1 3'UTR between 2 different body types of porcine breeds, Bama Xiang (BX) pigs, a miniature pig breed, and Large White (LW) pigs by sequencing. The secondary structure of the IGF-1 3'UTR mRNA containing the SNP in BX pigs is different from that of LW pigs. We then verified that there was a porcine miRNA (miR-new14) binding to this SNP in the 3'UTR of IGF-1 via cotransfecting the 3'UTR from the 2 breeds and miR-new14. We further found that the SNP downregulated mRNA and protein levels of IGF-1 by affecting the binding of miR-new14. To understand the function of miR-new14 in porcine kidney (PK-15) cells and its mechanism, cell proliferation and cell apoptosis assays were employed and results showed that proliferation viability of PK-15 cells was weakened and the apoptotic percentage of PK-15 cells was higher in the miR-new14 group. Porcine miRNA reduced the mRNA expression of AKT/ERK and protein levels of p-AKT/p-ERK. These results suggested that the expression of IGF-1 is influenced by this SNP and miR-new14 and that miR-new14 may suppress cell proliferation and promote cell apoptosis in PK-15 cells through regulating AKT and ERK signaling pathways, in which IGF-1 is involved.

MicroRNA124-IL6R Mediates the Effect of Nicotine in Inflammatory Bowel Disease by Shifting Th1/Th2 Balance Toward Th1

Epidemiological investigations have shown that smoking ameliorates ulcerative colitis (UC) but exacerbates Crohn's disease (CD), diseases that feature a Th2-mediated and Th1-mediated response, respectively. Cigarette extracts, especially nicotine, affect the Th1/Th2 balance. We previously reported that nicotine protects against mouse DSS colitis (similar to UC) by enhancing microRNA-124 (miR-124) expression. Intriguingly, elevation of miR-124 in CD is reported to aggravate the disease. Here we investigate the dual regulation of miR-124 in inflammatory bowel diseases (IBDs), which may explain the similar bidirectional regulation of tobacco. We found that overexpressed miR-124 protected against mouse DSS-induced colitis with a Th1 polarization in peripheral blood lymphocytes and colon tissues, which was also found in human peripheral blood lymphocytes. Conversely, miR-124 knockdown worsened DSS murine colitis with a Th2 polarization. Moreover, knockdown of miR-124 could eliminate the polarization toward Th1 after nicotine treatment, suggesting that miR-124 mediates the effect of nicotine on the Th1/Th2 balance. In addition, interference of IL-6R, which is a downstream target of miR-124, could remarkably weaken the Th1 polarization induced by miR-124. Taken together, these results suggest that nicotine shifts the balance of Th1/Th2 toward Th1 via a miR-124-mediated IL-6R pathway, which might explain its dual role in IBDs.

Circulating microRNA-590-5p functions as a liquid biopsy marker in non-small cell lung cancer

Despite the availability of various diagnostic procedures, a tissue biopsy is still indispensable for the routine diagnosis of lung cancer. However, inaccurate diagnoses can occur, leading to inefficient cancer management. In this context, use of circulating microRNAs (miRNAs) may serve as diagnostic tools as liquid biopsies, and as biomarkers to better understand the molecular mechanisms involved in the progression of cancer. We identified miR‐590‐5p as a potential prognostic marker in the progression of non‐small cell lung cancer (NSCLC). We were able to detect this miRNA in blood plasma samples of NSCLC patients through quantitative real‐time PCR. Our data showed an ~7.5‐fold downregulation of miR‐590‐5p in NSCLC patients compared to healthy controls, which correlated with several clinicopathological features. Further, overexpression of miR‐590‐5p led to decreased cell viability, proliferation, colony formation, migration, and invasion potential of lung cancer cells, whereas its knockdown showed the opposite effect. In addition, the levels of several proteins involved in the epithelial‐to‐mesenchymal transition negatively correlated with miR‐590‐5p levels in lung adenocarcinoma cells and tumors of NSCLC patients. Further, dual‐luciferase reporter assays identified STAT3 as a direct target of miR‐590‐5p, which negatively regulated STAT3 activation and its downstream signaling molecules (eg, Cyclin D1, c‐Myc, Vimentin, and β‐catenin) involved in tumorigenesis. Taken together, our study suggests that miR‐590‐5p functions as a tumor suppressor in NSCLC through regulating the STAT3 pathway, and may serve as a useful biomarker for the diagnosis/prognosis of NSCLC, and as a potential therapeutic target for the treatment of NSCLC.

MicroRNAs in non-small cell lung cancer: Gene regulation, impact on cancer cellular processes, and therapeutic potential

Lung cancer remains the most lethal cancer among men and women in the United States and worldwide. The majority of lung cancer cases are classified as non-small cell lung cancer (NSCLC). Developing new therapeutics on the basis of better understanding of NSCLC biology is critical to improve the treatment of NSCLC. MicroRNAs (miRNAs or miRs) are a superfamily of genome-derived, small noncoding RNAs that govern posttranscriptional gene expression in cells. Functional miRNAs are commonly dysregulated in NSCLC, caused by genomic deletion, methylation, or altered processing, which may lead to the changes of many cancer-related pathways and processes, such as growth and death signaling, metabolism, angiogenesis, cell cycle, and epithelial to mesenchymal transition, as well as sensitivity to current therapies. With the understanding of miRNA biology in NSCLC, there are growing interests in developing new therapeutic strategies, namely restoration of tumor suppressive miRNAs and inhibition of tumor promotive miRNAs, to combat against NSCLC. In this article, we provide an overview on the molecular features of NSCLC and current treatment options with a focus on pharmacotherapy and personalized medicine. By illustrating the roles of miRNAs in the control of NSCLC tumorigenesis and progression, we highlight the latest efforts in assessing miRNA-based therapies in animal models and discuss some critical challenges in developing RNA therapeutics.

Role of MicroRNA-124 as a Prognostic Factor in Multiple Neoplasms: A Meta-Analysis

Objective

MicroRNA-124 (miR-124) was revealed to be an attractive prognostic tumour biomarker in recent studies. However, the results remain inconclusive. Hence, this meta-analysis was carried out to clarify the precise predictive value of miR-124.

Materials and Methods

Relevant studies were searched in PubMed, EMBASE, Web of Science, and the Cochrane Library up to October 2018. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) were extracted from the selected studies.

Results

A total of 29 articles investigating the correlation between miR-124 expression and prognosis were initially identified. The pooled HR for overall survival (OS) of high miR-124 expression in multiple cancers was 0.55 (95%CI = 0.50–0.61). Disease-free survival (DFS)/progression-free survival (HR = 0.48, 95%CI = 0.38–0.61) revealed a protective role of increased miR-124 expression. Epigenetic hypermethylation of miR-124 mediated the silencing of its expression, which is correlated significantly with unfavourable survival (OS: HR = 2.06, 95%CI = 1.68–2.53; DFS/recurrence-free survival: HR = 2.77, 95%CI = 1.85–4.16).

Conclusions

Taken together, our results suggest that miR-124 plays an antioncogenic role in various tumors, such as lung cancer and colorectal cancer. If methylation of miR-124 could be prevented, progression and metastasis would be improved; thus, miR-124 may be a promising biomarker and novel therapeutic target. Further large-scale studies are needed to confirm this possible effect.

miR-124 Functions As A Melanoma Tumor Suppressor By Targeting RACK1

Background

miRNAs are small noncoding RNAs that function as posttranscriptional regulators during development and disease. Aberrant expression of miRNAs has been associated with various types of malignant tumors. Decreased levels of miR-124 have been observed in human cancers. RACK1 is a scaffold protein that acts as an oncogene in various human cancers. The association between miR-124 and RACK1 in melanoma has not been characterized.

Materials and methods

Real-time quantitative PCR was used to analyze RACK1 and miR-124 expression in melanoma tissue and cell lines. Dual-Luciferase reporter assay was performed to evaluate the effect of miR-124 inhibition on RACK1 expression. The effects of miR-124 on RACK1 in melanoma cell lines were evaluated using Western blot analysis and immunocytochemical staining. Wound-healing, transwell, and MTT assays, and annexin V-fluorescein isothiocyanate/propidium iodide followed by flow cytometry were used to evaluate the effects of miR-124 on RACK1-mediated proliferation, migration, invasion, and apoptosis of melanoma cells.

Results

The expression of miR-124 in melanoma tissue was lower than that in normal skin tissue, and the expression of RACK1 was higher in melanoma tissue than that in normal skin tissue. Analysis using Dual-Luciferase reporter assay showed that RACK1 was a direct target of miR-124. Western blot and immunocytochemical staining showed that the expression of RACK1 was significantly inhibited by miR-124 in both A375 and A875 melanoma cells. Furthermore, the results of functional experiments showed that degradation of RACK1 by miR-124 inhibited proliferation, migration, and invasion of melanoma cells, and promoted melanoma cell apoptosis.

Conclusion

The results suggested that miR-124 affected melanoma cells by directly targeting RACK1. miR-124 and RACK1 may be biomarkers for clinical diagnosis, and prognostic factors of human melanoma. Furthermore, miR-124 and RACK1 may be targets for the treatment of melanoma.

Overexpression of LIMD2 promotes the progression of non-small cell lung cancer

LIM domain containing 2 (LIMD2) is a small LIM-only protein that has been demonstrated to promote tumor progression; however, the expression and function of LIMD2 in non-small cell lung cancer (NSCLC) has not previously been reported. In the present study, reverse transcription-quantitative PCR and western blot analysis were conducted to examine the mRNA and protein expression levels of LIMD2. Cell Counting Kit-8, Transwell and wound-healing assays were performed in order to examine cell proliferation, invasion and migration, respectively. The data revealed that the LIMD2 expression levels were significantly increased in NSCLC tissues and cell lines, compared with adjacent non-tumor tissues and normal lung epithelial cells, respectively. In addition, the high expression of LIMD2 was significantly associated with lymph node metastasis, distant metastasis and advanced clinical stage in NSCLC. The patients with NSCLC with a high expression of LIMD2 exhibited shorter survival times than those with low LIMD2 expression. The knockdown of LIMD2 caused remarkable decreases in NSCLC cell proliferation, migration and invasion. Bioinformatics analysis and luciferase reporter gene assay data further confirmed that LIMD2 was a direct target gene of microRNA-124 (miR-124), a well-known tumor suppressor in NSCLC. The expression of LIMD2 was negatively regulated by miR-124 in NSCLC cells. In addition, miR-124 was downregulated in NSCLC tissues compared with adjacent non-tumor tissues, and an inverse correlation was observed between the expression of LIMD2 and miR-124 in NSCLC tissues. In conclusion, the present study demonstrates that LIMD2 serves an oncogenic role in NSCLC, suggesting that it may be used as a potential therapeutic target for the treatment of NSCLC.

High-intensity focused ultrasound inhibits invasion and metastasis of colon cancer cells by enhancing microRNA-124-mediated suppression of STAT3

Metastasis is the primary contributor to colorectal cancer mortality. High‐intensity focused ultrasound (HIFU) is an emerging technology for tumor therapy that exerts its effects through tumor ablation, mechanical disruption, and enhancement of immune responses. However, it remains unclear whether HIFU can influence tumor metastasis. Here, we examined the effect of HIFU on tumor metastasis of colorectal cancer cells and the underlying mechanisms. HIFU was observed to inhibit migration of HCT‐116 cells in vitro and suppress lung metastasis in a mouse model of colon cancer. In addition, HIFU up‐regulated microRNA (miR) ‐124 expression, which inhibited the activation of signal transducer and activator of transcription 3 (STAT3) and inhibited migration of HCT‐116 cells. Treatment with an inhibitor of miR‐124 reversed the effect of HIFU on cell migration. In conclusion, our results suggest that HIFU exerts anti‐metastatic effects in colon cancer, and this effect is possibly mediated via up‐regulation of miR‐124 and subsequent miR‐124‐mediated STAT3 suppression.

MicroRNA in Lung Cancer Metastasis

Tumor metastasis is a hallmark of cancer, with distant metastasis frequently developing in lung cancer, even at initial diagnosis, resulting in poor prognosis and high mortality. However, available biomarkers cannot reliably predict cancer spreading sites. The metastatic cascade involves highly complicated processes including invasion, migration, angiogenesis, and epithelial-to-mesenchymal transition that are tightly controlled by various genetic expression modalities along with interaction between cancer cells and the extracellular matrix. In particular, microRNAs (miRNAs), a group of small non-coding RNAs, can influence the transcriptional and post-transcriptional processes, with dysregulation of miRNA expression contributing to the regulation of cancer metastasis. Nevertheless, although miRNA-targeted therapy is widely studied in vitro and in vivo, this strategy currently affords limited feasibility and a few miRNA-targeted therapies for lung cancer have entered into clinical trials to date. Advances in understanding the molecular mechanism of metastasis will thus provide additional potential targets for lung cancer treatment. This review discusses the current research related to the role of miRNAs in lung cancer invasion and metastasis, with a particular focus on the different metastatic lesions and potential miRNA-targeted treatments for lung cancer with the expectation that further exploration of miRNA-targeted therapy may establish a new spectrum of lung cancer treatments.

Epigenetic alterations caused by aflatoxin b1: a public health risk in the induction of hepatocellular carcinoma

Aflatoxin B1 (AFB1) is currently the most commonly studied mycotoxin due to its great toxicity, its distribution in a wide variety of foods such as grains and cereals and its involvement in the development of + (hepatocellular carcinoma; HCC). HCC is one of the main types of liver cancer, and has become a serious public health problem, due to its high incidence mainly in Southeast Asia and Africa. Studies show that AFB1 acts in synergy with other risk factors such as hepatitis B and C virus leading to the development of HCC through genetic and epigenetic modifications. The genetic modifications begin in the liver through the biomorphic AFB1, the AFB1-exo-8.9-Epoxy active, which interacts with DNA to form adducts of AFB1-DNA. These adducts induce mutation in codon 249, mediated by a transversion of G-T in the p53 tumor suppressor gene, causing HCC. Thus, this review provides an overview of the evidence for AFB1-induced epigenetic alterations and the potential mechanisms involved in the development of HCC, focusing on a critical analysis of the importance of severe legislation in the detection of aflatoxins.

miRNA‑135a regulates Hut78 cell proliferation via the GATA‑3/TOX signaling pathway

The present study investigated the role of microRNA‑135a (miR‑135a) in cutaneous T‑cell lymphoma (CTCL) proliferation. Compared with the normal T lymphocyte control cell line, the mRNA and protein levels of GATA binding protein 3 (GATA‑3) were markedly increased in the Hut78 cell line and miR‑135a was markedly decreased (P<0.05). Based on bioinformatics, the target gene of miR‑135a was identified as GATA‑3. Dual luciferase and pre‑miR‑135a assays showed that miR‑135a regulated the translation of GATA‑3. In addition, the overexpression of miR‑135a mimics decreased the protein levels of GATA‑3 and thymocyte selection‑associated high mobility group box (TOX). The substantially increased mRNA and protein levels of GATA‑3 may be associated with the downregulation of miR‑135a, leading to T‑cell deregulation and proliferation through GATA‑3/TOX regulation and subsequently causing CTCL.

miR-124 and miR-142 enhance cisplatin sensitivity of non-small cell lung cancer cells through repressing autophagy via directly targeting SIRT1

Background: Drug resistance is a major obstacle in the treatment of non-small cell lung cancer (NSCLC). Recently, miRNAs are reported to be involved in the drug resistance of NSCLC. The roles of miR-124 and miR-142 in the multidrug resistance of NSCLC cells have been reported. However, the underlying mechanism by which miR-124 and miR-142 regulate resistance to cisplatin (CDDP) remains unknown. Methods: The expressions of miR-124, miR-142 and sirtuin 1 (SIRT1) in CDDP-sensitive and CDDP-resistant NSCLC tissues and cells were detected by qRT-PCR and western blot. IC50 value and cell proliferation were determined by MTT assay. Apoptosis was assessed by flow cytometry analysis. Autophagy was evaluated by western blot analysis of the protein levels of LC3-I, LC3-II and p62, and FITC-LC3 punctate formation assay. The interaction between miR-124 or miR-142 and SIRT1 was determined by luciferase reporter, RNA immunoprecipitation (RIP) and western blot assays. A tumor xenograft was performed to further validate the role of miR-124 and miR-142 in the sensitivity of CDDP-resistant NSCLC to cisplatin. Results: miR-124 and miR-142 were downregulated, while SIRT1 was upregulated in CDDP-resistant NSCLC tissues and cells compared to CDDP-sensitive groups. Functionally, overexpression of miR-124 and miR-142 or SIRT1 silencing enhanced the CDDP sensitivity of H1299/CDDP cells via suppressing autophagy, as evidenced by the reduced LC3-II/LC3-I radio, elevated p62 protein, and suppressed FITC-LC3 punctate formation in H1299/CDDP cells. miR-124 and miR-142 were demonstrated to co-target SIRT1. Re-expression of SIRT1 overturned miR-124 and miR-142-mediated chemosensitivity in H1299/CDDP cells via triggering autophagy. Conclusion: miR-124 and miR-142 enhance the cytotoxic effect of CDDP through repressing autophagy via targeting SIRT1 in CDDP-resistant NSCLC cells.

Drug resistance is a major obstacle in the treatment of non-small cell lung cancer (NSCLC).

MiR-125b-1-3p Exerts Antitumor Functions in Lung Carcinoma Cells by Targeting S1PR1

Background

MicroRNAs (miRNAs) have been extensively studied over the decades and have been identified as potential molecular targets for cancer therapy. To date, many miRNAs have been found participating in the tumorigenesis of non-small cell lung cancer (NSCLC). The present study was designed to evaluate the functions of miR-125b-1-3p in NSCLC cells.

Methods

MiR-125b-1-3p expression was detected in tissue samples from 21 NSCLC patients and in NSCLC cell lines using the real-time polymerase chain reaction. A549 cell lines were transfected with a miR-125b-1-3p mimic or miR-125b-1-3p antisense. Cell counting kit-8, wound healing, Matrigel invasion assays, and flow cytometry were used to assess the effects of these transfections on cell growth, migration, invasion, and apoptosis, respectively. Western blotting was used to detect apoptosis-related proteins, expression of S1PR1, and the phosphorylation status of STAT3. Significant differences between groups were estimated using Student's t-test or a one-way analysis of variance.

Results

MiR-125b-1-3p was downregulated in NSCLC samples and cell lines. Overexpression of miR-125b-1-3p inhibited NSCLC cell proliferation (37.8 ± 9.1%, t = 3.191, P = 0.013), migration (42.3 ± 6.7%, t = 6.321, P = 0.003), and invasion (57.6 ± 11.3%, t = 4.112, P = 0.001) and simultaneously induced more NSCLC cell apoptosis (2.76 ± 0.78 folds, t = 3.772, P = 0.001). MiR-125b-1-3p antisense resulted in completely opposite results. S1PR1 was found as the target gene of miR-125b-1-3p. Overexpression of miR-125b-1-3p inhibited S1PR1 protein expression (27.4 ± 6.1% of control, t = 4.083, P = 0.007). In addition, S1PR1 siRNA decreased STAT3 phosphorylation (16.4 ± 0.14% of control, t = 3.023, P = 0.015), as in cells overexpressing miR-125b-1-3p (16.7 ± 0.17% of control, t = 4.162, P = 0.026).

Conclusion

Our results suggest that miR-125b-1-3p exerts antitumor functions in NSCLC cells by targeting S1PR1.

In vitro and in vivo superior radiosensitizing effect of berbamine for head and neck squamous cell carcinoma

Background

Berbamine (BBM), one of the bis-benzylisoquinoline products isolated from Berberis amurensis, has been demonstrated for its anticancer effect against leukemia, breast cancer, liver cancer, etc. There are some studies focusing on the chemosensitization effect of BBM. However, there is no report about whether BBM could enhance the anticancer effect of radiation, which made us to explore the possible radiosensitization effect of BBM.

Materials and methods

Here, in vitro cytotoxicity of BBM was evaluated on two kinds of head and neck squamous cancer cell lines. Clonogenic assay was performed to study the radiosensitization effect of BBM. Western blot was utilized to elucidate the possible mechanism underlying the radiosensitization effect.

Results

BBM effectively inhibited the growth of two kinds of cancer cells in a time- and dose-dependent manner. Radiation plus BBM led to significantly more reduction of the colony-forming ability of cancer cells when compared with radiation alone. BBM plus radiation led to the most reduction of STAT3 phosphorylation, followed by the significant decrease of the ratio of Bax/Bcl-2. In vivo study demonstrated that the combinational administration of BBM and radiation generated the most significant tumor-delaying effect among all of the treatment regimens.

Conclusion

We reported, in the current study, the potential role of BBM in not only treating cancer by itself but also offering a promising way to improve the efficacy of radiotherapy by inhibiting the activation of STAT3 and subsequently inducing the apoptosis of cancer.

Multidimensional communication of microRNAs and long non-coding RNAs in lung cancer

PURPOSE

Non-coding RNAs (ncRNAs) have been a hot topic for many years in the field of cancer research, especially miRNAs and lncRNAs. Because they play critical roles in regulating various cellular processes and are more often involved in tumorigenesis than protein-coding genes. But the cross talk between miRNAs and lncRNAs in cancer has been scarcely studied. This article aims to provide a retrospective review of the latest research on the link between miRNAs and lncRNAs in lung cancer and discusses their potential role as diagnostic biomarkers and therapeutic targets for lung cancer in clinical practice.

METHODS

We reviewed literatures about ncRNAs and lung cancer from PUBMED databases in this article.

RESULTS

As shown in our review, miRNAs and lncRNAs could represent underlying targets for diagnosis, therapy, prognosis, and drug resistence of lung cancer. By acting as ceRNAs, lncRNAs can competitively inhibit the expression levels of miRNAs, and the lncRNA/miRNA axis can contribute to tumorigenesis, metastasis, and mutidrug resistance in lung cancer via various classic signaling pathways or related proteins.

CONCLUSION

Based on present knowledge, ncRNAs may provide a novel perspective to understand the pathogenesis of lung cancer and could be candidates in screening of therapeutic targets for lung cancer.

miR-124 regulates STAT3-mediated cell proliferation, migration and apoptosis in bladder cancer

The etiology and pathogenesis of bladder cancer (BCa) is complex. MicroRNA (miRNA) has been implicated in BCa. Targeting of signal transducer and activator of transcription 3 (STAT3) by miR-124 to regulate tumorigenesis has been demonstrated in other types of cancer. In the present study, miR-124 levels were downregulated in the BCa T24 cell line and STAT3 was increased in BCa cell lines. Transfection of miR-124 mimics into T24 cells significantly inhibited STAT3 expression. A luciferase assay confirmed that miR-124 directly targeted the STAT3 3'untranslated region to inhibit STAT expression. Knockdown of STAT3 expression led to increased apoptosis of T24 cells and reduced tumor growth in vitro. The results demonstrated the molecular mechanisms and biological functions of the miR-124/STAT3 signal pathway at the cellular level and indicate the potential of miR-124 as a therapeutic target for BCa.

Comprehensive Assessment of the Relationship Between MicroRNA-124 and the Prognostic Significance of Cancer

BACKGROUND

Numerous studies have demonstrated the presence of microRNA-124 abnormalities involving gene expression, methylation, and single nucleotide polymorphism (SNP) in multiple and diverse cancers, but the prognostic value of these abnormalities in cancer remains inconclusive.

OBJECTIVE

The aim of this study is to determine the prognostic value of miR-124 in cancer.

METHODS

We scrutinized the electronic databases and estimate the association between miR-124 expression, methylation and single nucleotide polymorphisms (SNPs), and prognosis in cancers. The pooled hazard ratios with 95% confidence intervals (CIs) for overall survival (OS), and disease-free survival/recurrence-free survival (RFS)/progression-free survival (PFS) were calculated to estimate the effects of miR-124 expression, methylation, and SNPs on cancer prognosis. The Quality in Prognosis Studies and Newcastle-Ottawa Scale were utilized to assess the quality of included studies.

RESULTS

A total of 20 studies involving 3,574 participants were analyzed in evidence synthesis. Our findings showed that the low expression of miR-124 was significantly associated with poor OS (HR = 2.37, 95% CI: 1.91-2.94, P = 0.00; HR = 3.10, 95% CI: 2.04-4.70, P = 0.00) and PFS/RFS (HR = 2.21, 95% CI: 1.50-3.26, P = 0.00; HR = 2.12, 95% CI: 1.20-3.74, P = 0.00). The hyper-methylation of miR-124 was associated with poor OS (HR = 2.09, 95% CI: 1.48-2.95, P = 0.00) and PFS (HR = 3.70, 95% CI: 1.72-7.97, P = 0.00) (Table 3). The patients carrying with Allele C of miR-124 rs5315649 had a worse OS (HR = 1.50, 95% CI: 1.09-2.07, P = 0.00) and PFS (HR = 1.67, 95% CI: 1.20-2.33, P = 0.00) than the carriers with Allele G.

CONCLUSION

The low expression and hyper-methylation of miR-124 was strongly associated with poor prognosis, and genetic variations of miR-124 rs531564 affected prognosis in cancer patients.

Decreased expression of microRNA-214 contributes to imatinib mesylate resistance of chronic myeloid leukemia patients by upregulating ABCB1 gene expression

The aim of the present study was to determine the expression of adenosine triphosphate binding cassette subfamily B member 1 (ABCB1) gene and its protein P-glycoprotein (PGP) in bone marrow mononuclear cells from chronic myeloid leukemia (CML) patients with imatinib mesylate (IM) resistance, or IM-resistant CML K562 cells. In addition, the molecular mechanism of action of microRNA (miR)-214 on ABCB1 in IM resistance was investigated. A total of 26 CML patients with IM resistance were included in the present study. In addition, 31 CML patients who did not have IM resistance were included as the control group. Bone marrow was collected from all subjects. The K562R cell line, which is a K562 cell line with IM resistance, was used for cellular studies. Reverse transcription-quantitative polymerase chain reaction was used to determine the expression of ABCB1 mRNA and miR-214 in cells. Western blotting was employed to determine the expression of PGP. Dual luciferase reporter assay was carried out to identify interactions between ABCB1 mRNA and miR-214. MTT assay was used to determine the survival rate of cells. ABCB1 mRNA and PGP expression was upregulated in bone marrow mononuclear cells from CML patients with IM resistance. K562R cells had higher ABCB1 and PGP expression than K562 cells, potentially due to their different sensitivity to IM. Expression miR-214 was decreased in bone marrow mononuclear cells from patients with IM resistance and K562R cells. Notably, miR-214 was able to bind with the 3′-untranslated region, seed region of ABCB1 mRNA to regulate its expression. In addition, elevated expression of miR-214 restored IM sensitivity to K562R cells potentially by affecting ABCB1 expression. The present study demonstrated that upregulated expression of ABCB1 mRNA and PGP in bone marrow mononuclear cells from CML patients with IM resistance may be associated with the downregulation of miR-214. In addition, miR-214 may participate in the IM resistance of CML patients by regulating ABCB1 expression.

MicroRNA-124-3p represses cell growth and cell motility by targeting EphA2 in glioma

MiR-124-3p and EphA2 are aberrantly expressed in glioma tissue specimens. In the present study, we firstly investigated that miR-124-3p inhibits EphA2 expression mediated by binding its 3'-UTR to regulate the progression of human glioma. The U87MG and LN229 cells were transfected with miR-124-3p mimics and/or siRNA-EphA2, and then the role of miR-124-3p and EphA2 in the colony-formation, cell-cycle, migration and invasion of glioma cells in vitro were examined. Proteins involved in the epithelial-mesenchymal transition were examined using western blot. The results showed that miR-124-3p was significantly downregulated in glioma tissues, whereas a marked upregulation of EphA2 expression was found. Colony-formation and flow cytometry assays demonstrated that EphA2 downregulation or miR-124-3p mimics caused growth and cell-cycle inhibition in glioma. Transwell migration and invasion assays demonstrated that EphA2 downregulation or miR-124-3p mimics suppressed the migration and invasion of glioma cells. EphA2 downregulation or miR-124-3p mimics reduced the level of vimentin in U87MG and LN229 cells. In conclusion, miR-124-3p was found to suppress the growth, migration and invasion of glioma cells in vitro via EphA2. Furthermore, we validated miR-124-3p enforced its biological modulation via targeting EphA2 through the rescue experiment. Conclusively, our study proclaimed that miR-124-3p can counteract the malignant phenotypes of glioma cells by the inhibitory effect of the EphA2.

MicroRNA-218 inhibits the migration, epithelial-mesenchymal transition and cancer stem cell properties of prostate cancer cells

MicroRNA (miRNA) is a class of non-coding single-stranded RNA, able to regulate tumor-associated genes via binding the 3'-UTR of the target gene mRNA. Previous publications have demonstrated that miRNA-218 (miR-218) acts as a tumor-suppressive miRNA in various types of human cancer, including prostate cancer (PCa). However, the role of miR-218 in regulating PCa cell stemness and epithelial-mesenchymal transition remains unknown and requires further research. In the present study, it is demonstrated that miR-218 was downregulated in 2 PCa cell lines and could suppress cell migration, EMT and the exhibition of cancer stem cell-like properties. The expression of GLI family zinc finger 1 (Gli1) was inhibited by miR-218 overexpression, suggesting miR-218-suppression of Gli1 as a potential mechanism for the tumor-suppressive effect of miR-218. Overall, the results indicate that miR-218 served a critical role in the inhibition of PCa development. This may provide new insight for elucidating the mechanisms of PCa oncogenesis and suggests that miR-218 may be a novel therapeutic target for PCa.

MicroRNA-27a participates in the pathological process of depression in rats by regulating VEGFA

The present study aimed to determine the expression of vascular endothelial growth factor A (VEGFA) and microRNA (miRNA/miR)-27a in hippocampal tissues, and serum from a depression model of rats. In addition, the present study aimed to understand the mechanism of regulation of miR-27a in depression. A total of 40 male rats were selected, and divided into the control and depression model groups. The rats in the model group were subjected to 14 types of stimulations to model depression. By determining the body weight, syrup consumption rate and open field test score, the extent of depression in the rats was evaluated. Quantitative-polymerase chain reaction was used to determine the expression of VEGFA mRNA and miR-27a in hippocampal tissues, and serum. ELISA was used to measure the content of VEGFA protein in serum, while western blotting was employed to determine the expression of VEGFA protein in hippocampal tissues. A dual luciferase assay was carried out to identify the interactions between VEGFA mRNA and miR-27a. The rats in the depression model group showed depression symptoms and the depression model was successfully constructed. Rats with depression had lower VEGFA mRNA and protein expression in the hippocampus, and peripheral blood compared with the control group. Rats in the depression model group had reduced levels of miR-27a in the hippocampus and peripheral blood, which may be associated with the levels of VEGFA. miR-27a was able to bind with the 3′-untranslated region of VEGFA mRNA to regulate its expression. The present study demonstrated that miR-27a expression in hippocampal tissues and blood from rats with depression is upregulated, while the expression of VEGFA mRNA and protein is downregulated. miR-27a may participate in the pathological process of depression in rats by regulating VEGFA.

The miR-124-p63 feedback loop modulates colorectal cancer growth

Among the diverse co-regulatory relationships between transcription factors (TFs) and microRNAs (miRNAs), feedback loops have received the most extensive research attention. The co-regulation of TFs and miRNAs plays an important role in colorectal cancer (CRC) growth. Here, we show that miR-124 can regulate two isoforms of p63, TAp63 and ΔNp63, via iASPP, while p63 modulates signal transducers and activators of transcription 1 (STAT1) expression by targeting miR-155. Moreover, STAT1 acts as a regulator of CRC growth by targeting miR-124. Taken together, these results reveal a feedback loop between miRNAs and TFs. This feedback loop comprises miR-124, iASPP, STAT1, miR-155, TAp63 and ΔNp63, which are essential for CRC growth. Moreover, this feedback loop is perturbed in human colon carcinomas, which suggests that the manipulation of this microRNA-TF feedback loop has therapeutic potential for CRC.

circHIPK3 regulates cell proliferation and migration by sponging miR-124 and regulating AQP3 expression in hepatocellular carcinoma

Noncoding RNAs plays an important role in hepatocellular carcinoma (HCC). Here, we show that miR-124 was downregulated in HCC tissues and that the ectopic expression of miR-124 inhibited the proliferation and migration of HCC cells. We proposed that aquaporin 3 (AQP3) is a direct target of miR-124. AQP3 was upregulated in HCC tissues and inversely correlated with miR-124 expression. The overexpression of miR-124 decreased AQP3 expression. Indeed, AQP3 overexpression promoted cell proliferation and migration, whereas miR-124 knockdown suppressed cell proliferation and migration. Furthermore, we found that circular RNA HIPK3 (circHIPK3) acted as a miR-124 sponge and regulated the expression of the miR-124 target gene AQP3. circHIPK3 was upregulated in HCC tissues and positively correlated with AQP3 expression. Thus, silencing circHIPK3 inhibited cell proliferation and migration by downregulating AQP3 expression. Moreover, miR-124 inhibition rescued circHIPK3 knockdown induced reduction in cell proliferation and migration, as well as AQP3 expression. In vivo experiments also confirmed that circHIPK3 regulated xenograft tumor growth via the miR-124-AQP3 axis. These observations indicate a possible novel therapeutic strategy involving circular RNAs in HCC.

Long non-coding RNA H19 suppresses retinoblastoma progression via counteracting miR-17-92 cluster

Long non-coding RNAs (lncRNAs) are frequently dysregulated and play important roles in many cancers. lncRNA H19 is one of the earliest discovered lncRNAs which has diverse roles in different cancers. However, the expression, roles, and action mechanisms of H19 in retinoblastoma are still largely unknown. In this study, we found that H19 is downregulated in retinoblastoma tissues and cell lines. Gain-of-function and loss-of-function assays showed that H19 inhibits retinoblastoma cell proliferation, induces retinoblastoma cell cycle arrest and cell apoptosis. Mechanistically, we identified seven miR-17-92 cluster binding sites on H19, and found that H19 directly bound to miR-17-92 cluster via these seven binding sites. Through binding to miR-17-92 cluster, H19 relieves the suppressing roles of miR-17-92 cluster on p21. Furthermore, H19 represses STAT3 activation induced by miR-17-92 cluster. Hence, our results revealed that H19 upregulates p21 expression, inhibits STAT3 phosphorylation, and downregulates the expression of STAT3 target genes BCL2, BCL2L1, and BIRC5. In addition, functional assays demonstrated that the mutation of miR-17-92 cluster binding sites on H19 abolished the proliferation inhibiting, cell cycle arrest and cell apoptosis inducing roles of H19 in retinoblastoma. In conclusion, our data suggested that H19 inhibits retinoblastoma progression via counteracting the roles of miR-17-92 cluster, and implied that enhancing the action of H19 may be a promising therapeutic strategy for retinoblastoma.

Prognostic role of STAT3 in solid tumors: a systematic review and meta-analysis

Accumulated studies have provided controversial evidences of the association between signal transducer and activator of transcription proteins 3 (STAT3) expression and survival of human solid tumors. To address this inconsistency, we performed a meta-analysis with 63 studies identified from PubMed, Medline and EBSCO. We found STAT3 overexpression was significantly associated with worse 3-year overall survival (OS) (OR = 2.06, 95% CI = 1.57 to 2.71, P < 0.00001) and 5-year OS (OR = 2.00, 95% CI = 1.53 to 2.63, P < 0.00001) of human solid tumors. Similar results were observed when disease free survival (DFS) were analyzed. Subgroup analysis showed that elevated STAT3 expression was associated with poor prognosis of gastric cancer, lung cancer, gliomas, hepatic cancer, osteosarcoma, prostate cancer, pancreatic cancer but better prognosis of breast cancer. The correlation between STAT3 and survival of solid tumors was related to its phosphorylated state. High expression level of STAT3 was also associated with advanced tumor stage. In conclusion, elevated STAT3 expression is associated with poor survival in most solid tumors. STAT3 is a valuable biomarker for prognosis prediction and a promising therapeutic target in human solid tumors.

MicroRNA-124-3p directly targets PDCD6 to inhibit metastasis in breast cancer

Breast cancer (BC) is the leading cause of cancer-associated mortality among women worldwide, with a poor 5-year survival rate, particularly among patients with metastatic BC. Previous studies have indicated that the dysregulation of microRNAs (miRNAs/miRs) is associated with carcinogenesis and metastasis. Thus, investigating the underlying molecular mechanisms by which miRNAs mediate their effects may aid in the improvement of BC treatment. In the present study, reverse transcription-quantitative polymerase chain reaction analyses were performed to investigate miR-124-3p expression in BC tissues. The expression of miR-124-3p was significantly decreased in primary BC tissues compared with that in adjacent non-tumor tissues. Downregulated miR-124-3p was correlated with lymph node metastasis and a low overall survival time. Wound-healing and Transwell assays revealed that MDA-MB-231 and MCF-7 cell motility was inhibited by miR-124-3p, but was promoted by a miR-124-3p inhibitor. Overexpression of miR-124-3p increased levels of E-cadherin, and decreased levels of N-cadherin and Vimentin, indicating that miR-124-3p inhibits the epithelial-mesenchymal transition. In addition, a bioinformatics analysis and subsequent in vitro experiments identified programmed cell death protein 6 (PDCD6) as a direct target of miR-124-3p. Restoration of PDCD6 expression impaired the metastasis inhibitor role of miR-124-3p by promoting cell invasion. Furthermore, the expression of miR-124-3p was inversely associated with PDCD6 mRNA levels in clinical breast tumors. Taken together, these data suggest that miR-124-3p inhibits tumor metastasis by inhibiting PDCD6 expression, and that the miR-124-3p/PDCD6 signaling axis may be a potential target for novel treatments in patients with advanced BC.

IL-1β-induced NF-κB activation down-regulates miR-506 expression to promotes osteosarcoma cell growth through JAG1

Nowadays, the role of miRNA in tumorigenesis has been largely reported. It was found that miR-506 might be associated with tumorigenesis of various cancers. The present study was aimed to investigate the character of miR-506 and some related factors in human osteosarcoma (OS) carcinogenesis. The expression level of miR-506 was downregulated in OS compared with the normal control group by RT-PCR, both in vivo and in vitro. In addition, IL-1β stimulation decreased the expression of miR-506. MiR-506 interfered with JAG1 gene transcription throughmiR-506 binding to the 3'-UTR region of JAG1 gene. Further siRNA strategy suggested that IL-1β may regulate miR-506 level via NF-κB, and then alter the JAG1 expression. Besides, the suppression of JAG1 by miR-506 inhibited OS cell proliferation. Taken together, our data indicate a process of NF-κB-induced miR-506 suppression and JAG1 upregulation upon IL-1β induction, which can be regarded as a new pathway for modulating cell proliferation via miR-506. It may be of clinical value in treating OS in the future.

Unique circulating microRNAs in relation to EGFR mutation status in Japanese smoker male with lung adenocarcinoma

The incidence of lung adenocarcinoma has been increasing recently in smokers. The molecular target therapy has been developed for lung adenocarcinoma patients harboring EGFR gene mutation. However, the treatment modalities for patients without mutation are currently limited. Thus, analysis of EGFR gene mutation status at early stage is important strategy to classify the patients for improving treatments and prognosis efficiently. This study aimed to identify microRNA (miRNA) signature in relation to mutation status in EGFR gene in early stage of lung adenocarcinoma male patients with smoking history. MiRNA profiles were assessed by microarray in paired plasma and tissue pooled from 10 EGFR wild type (EGFR-wt) and 10 EGFR mutated (EGFR-mut) patients. Expressions of selected miRNAs were verified further by real-time qRT-PCR in 83 plasma samples consisting of 55 EGFR-wt patients and 28 EGFR-mut patients and their correlation with clinicopathological parameters and EGFR gene mutation status were evaluated. We found that seven miRNAs (miR-16-5p, miR-23a-3p, miR-103a-3p, miR122-5p, miR-223-3p, miR-346 and miR-451a) were differentially expressed in stage I and stage I+II. Especially, miR-23a-3p was only miRNA shown higher expression in EGFR-wt patients than EGFR-mut patients. Thus, our findings could be useful non-invasive biomarkers to differentiate mutation status in EGFR gene in smoker lung adenocarcinoma male patients.

The relationship between microRNAs and the STAT3-related signaling pathway in cancer

MicroRNAs are non-coding RNAs that regulate gene expression by targeting messenger RNA molecules in 3' untranslated region. Mounting evidence indicates that microRNAs regulate several factors to influence various biological activities that are related to carcinogenesis, including signal transducer and activator of transcription 3, which is a transcription factor that also acts as an oncogene. MicroRNAs influence signal transducer and activator of transcription 3 either by directly targeting or via other pathway components upstream or downstream of signal transducer and activator of transcription 3 such as Janus kinases, members of the suppressor of cytokine signaling family, and other genes that regulate cell proliferation, apoptosis, migration, invasion, and epithelial-mesenchymal transition. However, signal transducer and activator of transcription 3 activation changes the pattern of expression of microRNAs and mediates tumorigenesis. Moreover, the relationship between signal transducer and activator of transcription 3 and microRNAs varies among different kinds of cancers. A specific microRNA may act as an oncogene or tumor suppressor in different cancers, and microRNAs also directly or indirectly regulate signal transducer and activator of transcription 3 via pathways in the same cancers. In this review, we focus on the reciprocal regulation and roles of microRNAs and signal transducer and activator of transcription 3 in cancer, as well as describe current research progress on this relationship. A better understanding of this relationship may facilitate in the identification of targets for clinical therapeutics.

MicroRNA-124 suppresses proliferation and glycolysis in non-small cell lung cancer cells by targeting AKT-GLUT1/HKII

Non-small cell lung cancer accounts for 85% of all types of lung cancer and is the leading cause of worldwide cancer-associated mortalities. MiR-124 is epigenetically silenced in various types of cancer and plays important roles in tumor development and progression. MiR-124 was also significantly downregulated in non-small cell lung cancer patients. Glycolysis has been considered as a feature of cancer cells; hypoxia-inducible factor 1-alpha/beta and Akt are key enzymes in the regulation of glycolysis and energy metabolism in cancer cells. However, the role of miR-124 in non-small cell lung cancer cell proliferation, glycolysis, and energy metabolism remains unknown. In this research, cell proliferation was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; furthermore, glucose consumption and lactic acid production were assessed; adenosine triphosphate content and NAD⁺/NADH were also detected. These tests were conducted using the normal non-small cell lung cancer cell line A549, which was transfected variedly with miR-mimics, miR-124 mimics, miR-124 inhibitor, pc-DNA3.1(+)-AKT1, and pc-DNA3.1(+)-AKT2 plasmid. Here, we show that miR-124 overexpression directly decreased cell growth, glucose consumption, lactate production, and energy metabolism. MiR-124 also negatively regulates glycolysis rate-limiting enzymes, glucose transporter 1 and hexokinase II. Our results also showed that miR-124 negatively regulates AKT1 and AKT2 but no regulatory effect on hypoxia-inducible factor 1-alpha/beta. Overexpression of AKT reverses the inhibitory effect of miR-124 on cell proliferation and glycolytic metabolism in non-small cell lung cancer. AKT inhibition blocks miR-124 silencing-induced AKT1/2, glucose transporter 1, hexokinase II activation, cell proliferation, and glycolytic or energy metabolism changes. In summary, this study demonstrated that miR-124 is able to inhibit proliferation, glycolysis, and energy metabolism, potentially by targeting AKT1/2-glucose transporter 1/hexokinase II in non-small cell lung cancer cells.

Identification of miR‑124a as a novel diagnostic and prognostic biomarker in non‑small cell lung cancer for chemotherapy

Previous studies have suggested that dysregulation of microRNA (miR) −124a is associated with various types of human cancer. However, there are few studies reporting the level of miR-124a expression in non-small cell lung cancer (NSCLC). The present study investigated the association between miR-124a and NSCLC by analyzing the differential expression of miR-124a in NSCLC using the GEO database, as well as subsequently performing reverse transcription-quantitative polymerase chain reaction analysis on 160 NSCLC biopsies, 32 of which were paired with adjacent normal tissues. The results indicated that mir-124a expression levels were decreased in NSCLC tumor biopsies compared with adjacent normal tissues. The overall survival (OS) in patients with a high expression of miR-124a was prolonged relative to patients with low expression of miR-124a. The expression levels of miR-124a were associated with clinical characteristics, including lymph-node metastasis, tumor differentiation, tumor node metastasis (TNM) stage and diameter. Frequently, lymph-node metastasis, TNM stage, diameter and lack of chemotherapy have been associated with a worse prognosis in patients. In addition, the present study identified that high expression of miR-124awith chemotherapy may increase OS. In conclusion, the current study demonstrated that miR-124a was downregulated in NSCLC, and miR-124a was a potential prognostic tumor biomarker response to chemotherapy.

The microRNA miR-124 inhibits vascular smooth muscle cell proliferation by targeting S100 calcium-binding protein A4 (S100A4)

S100 calcium-binding protein A4 (S100A4) induces proliferation and migration of vascular smooth muscle cells (VSMCs). We aimed to find the microRNA regulating S100A4 expression. S100A4 transcripts are abruptly increased in the acute phase of carotid arterial injury 1 day later (at day 1) but gradually decreases at days 7 and 14. Bioinformatics analysis reveals that miR-124 targets S100A4. VSMC survival is attenuated by miR-124 mimic but increased by miR-124 inhibitor. miR-124 decreases immediately after carotid arterial injury but dramatically increases at days 7 and 14. miR-124 inhibitor-induced cell proliferation is blocked by S100A4 siRNA, whereas miR-124-induced cell death is recovered by S100A4. Our findings suggest that miR-124 is a novel regulator of VSMC proliferation and may play a role in the development of neointimal proliferation.

MicroRNA-124 regulates the radiosensitivity of non-small cell lung cancer cells by targeting TXNRD1

Radiation treatment remains one of the major modalities in the treatment of lung cancer. Although the majority of patients initially respond to treatment with radiation, resistance inevitably develops and leads to treatment failure. Therefore, the identification of the underlying molecular mechanisms of radiation resistance may facilitate the development of novel approaches for overcoming resistance, and enhance the efficacy of treatment with radiation in lung and other types of cancer. In the present study we established three radiation-resistant sub-cell lines derived from the radiation-sensitive lung cancer cell line HCC827. Using a polymerase chain reaction microRNA (miRNA) array, multiple miRNAs were identified to be markedly downregulated in radiation-resistant cells, including miRNA (miR)-124, miR-191 and miR-205. It was observed that overexpression of miR-124 sensitized the resistant cells to treatment with radiation and that thioredoxin reductase 1 (TXNRD1) is a novel target of miR-124. Furthermore, it was demonstrated that knockdown of TXNRD1 using small interfering RNA increased the basal level of reactive oxygen species and sensitized the cells to radiation treatment. The results of the present study demonstrated that multiple miRNAs are downregulated in radiation-resistant lung cancer cells and that downregulation of miR-124 mediates radiation resistance through the targeting of TXNRD1 mRNA expression. The present study revealed a novel molecular mechanism of miRNA-mediated radiation resistance and identified miR-124-regulated TXNRD1 as a novel therapeutic target for overcoming radiation resistance in the treatment of lung cancer.

miR-98 inhibits hepatocellular carcinoma cell proliferation via targeting EZH2 and suppressing Wnt/β-catenin signaling pathway

Hepatocellular carcinoma (HCC) is a highly aggressive solid malignancy in the word. Aberrant microRNA (miRNA) expression is involved in human diseases including cancer. In the current study, we explore the function of miR-98 in HCC cell proliferation. We found that expression level of miR-98 was significantly decreased in HCC tissues and cells lines compared with adjacent non-tumor issues and human hepatic cell line LO2. Increased expression of miR-98 suppressed HCC cell proliferation and arrested HCC cell cycle in G0/G1 phase. While, suppressed expression of miR-98 showed the opposite effect. Bioinformatics analysis revealed EZH2, a putative tumor promoter as a potential target of miR-98. Additionally, luciferase reporter assay revealed that miR-98 directly binds to the 3'-untranslated region (3'-UTR) of EZH2 mRNA. Furthermore, we demonstrated that miR-98 could reduce the Wnt/β-catenin signal pathway by suppressing EZH2 directly. Moreover, inhibition of EZH2 abrogated the effect of miR-98 inhibitor on HCC cell proliferation. Taken together, these results suggested that miR-98 functioned as a potential tumor suppressor by regulating Wnt/β-catenin signal pathway through direct suppression of EZH2 expression and might sever as a potential therapeutic target for HCC patients.