miR-26a-5p Inhibit Gastric Cancer Cell Proliferation and Invasion Through Mediated Wnt5a

BRD4 expression and its regulatory interaction with miR-26a-3p, DLG5-AS1, and JMJD1C-AS1 lncRNAs in gastric cancer progression

Gastric cancer remains a significant health challenge despite advancements in diagnosis and treatment. Early detection is critical to reducing mortality, necessitating the investigation of molecular mechanisms underlying gastric cancer progression. This study focuses on BRD4 expression and its correlation with miR-26a-3p, DLG5-AS1, and JMJD1C-AS1 lncRNAs in gastric cancer. Analysis of The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets revealed significant upregulation of BRD4 in gastric cancer tissues compared to normal tissues, correlating negatively with miR-26a-3p and positively with DLG5-AS1 and JMJD1C-AS1 lncRNAs. Quantitative RT-PCR confirmed these findings in 25 gastric cancer tissue samples and 25 normal samples. BRD4's overexpression was associated with reduced survival rates and older patient age. MiR-26a-3p, a known tumor suppressor, showed decreased expression in gastric cancer tissues, with ROC analysis suggesting it, alongside BRD4, as a potential diagnostic biomarker. Additionally, bioinformatics predicted miR-26a-3p's interaction with BRD4 mRNA. Upregulated lncRNAs DLG5-AS1 and JMJD1C-AS1 likely act as competing endogenous RNAs, sponging miR-26a-3p, thus promoting BRD4 dysregulation. These lncRNAs have not been previously studied in gastric cancer. The findings propose a novel BRD4/lncRNA/miRNA regulatory axis in gastric cancer, highlighting the potential of BRD4, DLG5-AS1, and JMJD1C-AS1 as biomarkers for early diagnosis. Further studies with larger sample sizes and in vivo and in vitro experiments are needed to elucidate this regulatory mechanism's role in gastric cancer progression.

PXMP4 promotes gastric cancer cell epithelial-mesenchymal transition via the PI3K/AKT signaling pathway

BACKGROUND

Peroxisomal membrane protein 4 (PXMP4), a member of the peroxisome membrane protein PXMP2/4 family, participates in the progression of several malignant cancers. Nevertheless, the effect of PXMP4 in the development of gastric cancer (GC) is still unknown. As a result, the focus of this investigation was to elucidate the potential mechanisms of PXMP4 in GC.

METHODS AND RESULTS

Firstly, bioinformatics analysis results showed higher expression of PXMP4 in GC tissues. Secondly, clinical analysis of 57 patients with GC revealed correlations between PXMP4 expression and differentiation, depth of invasion, as well as TNM stage. Furthermore, individuals with elevated PXMP4 expression in GC exhibited an unfavorable prognosis. In vitro data showed the involvement of knockdown/overexpression of PXMP4 in the proliferation, invasion, and migration of GC cells, and triggering the epithelial-mesenchymal transition (EMT) of GC cells through the activation of the PI3K/AKT signaling pathway. LY294002, a PI3K/AKT inhibitor, inhibited the expression of PI3K/AKT-related proteins but did not affect the expression of PXMP4.

CONCLUSIONS

These findings indicate that PXMP4 potentially functions as an upstream molecule in the PI3K/AKT pathway, governing the EMT process in GC.

MicroRNA-26a alleviates tubulointerstitial fibrosis in diabetic kidney disease by targeting PAR4

Our previous study found that miR-26a alleviates aldosterone-induced tubulointerstitial fibrosis (TIF). However, the effect of miR-26a on TIF in diabetic kidney disease (DKD) remains unclear. This study clarifies the role and possible mechanism of exogenous miR-26a in controlling the progression of TIF in DKD models. Firstly, we showed that miR-26a was markedly decreased in type 2 diabetic db/db mice and mouse tubular epithelial cells (mTECs) treated with high glucose (HG, 30 mM) using RT-qPCR. We then used adeno-associated virus carrying miR-26a and adenovirus miR-26a to enhance the expression of miR-26a in vivo and in vitro. Overexpressing miR-26a alleviated the TIF in db/db mice and the extracellular matrix (ECM) deposition in HG-stimulated mTECs. These protective effects were caused by reducing expression of protease-activated receptor 4 (PAR4), which involved in multiple pro-fibrotic pathways. The rescue of PAR4 expression reversed the anti-fibrosis activity of miR-26a. We conclude that miR-26a alleviates TIF in DKD models by directly targeting PAR4, which may provide a novel molecular strategy for DKD therapy.

miR-26a is a Key Therapeutic Target with Enormous Potential in the Diagnosis and Prognosis of Human Disease

MicroRNA-26a (miR-26a) belongs to small non-coding regulatory RNA molecules emerging as fundamental post-transcriptional regulators inhibiting gene expression that plays vital roles in various processes of human diseases such as depression, renal ischemia and reperfusion injury, liver injury and some refractory cancer. In this review, we expound on the results of studies about miR-26a with emphasis on its function in animal models or in vitro cell culture to simulate the most common human disease in the clinic. Furthermore, we also illustrate the underlying mechanisms of miR-26a in strengthening the antitumor activity of antineoplastic drugs. Importantly, dysregulation of miR-26a has been related to many chronic and malignant diseases, especially in neurological disorders in the brain such as depression and neurodegenerative diseases as well as cancers such as papillary thyroid carcinoma, hepatocellular carcinoma and so on. It follows that miR-26a has a strong possibility to be a potential therapeutic target for the treatment of neurological disorders and cancers. Although the research of miRNAs has made great progress in the last few decades, much is yet to be discovered, especially regarding their underlying mechanisms and roles in the complex diseases of humans. Consequently, miR-26a has been analyzed in chronic and malignant diseases, and we discuss the dysregulation of miR-26a and functional roles in the development and pathogenesis of these diseases, which is very helpful for understanding their mechanisms as new biomarkers for diagnosing and curing diseases in the near future.

Transcriptionally regulated miR-26a-5p may act as BRCAness in Triple-Negative Breast Cancer

BACKGROUND

DNA damage and DNA damage repair (DDR) are important therapeutic targets for triple-negative breast cancer (TNBC), a subtype with limited chemotherapy efficiency and poor outcome. However, the role of microRNAs in the therapy is emerging. In this study, we explored whether miR-26a-5p could act as BRCAness and enhance chemotherapy sensitivity in TNBC.

METHODS

Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to detect the expression of miR-26a-5p in breast cancer tissues and cell lines. CCK-8 was used to measure drug sensitivity in concentration gradient and time gradient. Comet assay was used to detect DNA damage. Flow cytometry was performed to examine apoptosis. Moreover, we used western blot and immunofluorescence to detect biomarkers. Luciferase reporter assay was performed to verify the combination of miR-26a-5p and 3'UTR of target gene. Hormone deprivation and stimulation assay were used to validate the effect of hormone receptors on the expression of miR-26a-5p. Chromatin immunoprecipitation (ChIP) assays were used to verify the binding sites of ER-a or PR with the promoter of miR-26a-5p. Animal experiments were performed to the effect of miR-26a-5p on Cisplatin treatment.

RESULTS

The expression of miR-26a-5p was significantly downregulated in TNBC. Overexpressing miR-26a-5p enhanced the Cisplatin-induced DNA damage and following apoptosis. Interestingly, miR-26a-5p promoted the expression of Fas without Cisplatin stimulating. It suggested that miR-26a-5p provided a hypersensitivity state of death receptor apoptosis and promoted the Cisplatin sensitivity of TNBC cells in vitro and in vivo. Besides, miR-26a-5p negatively regulated the expression of BARD1 and NABP1 and resulted in homologous recombination repair defect (HRD). Notably, overexpressing miR-26a-5p not only facilitated the Olaparib sensitivity of TNBC cells but also the combination of Cisplatin and Olaparib. Furthermore, hormone receptors functioned as transcription factors in the expression of miR-26a-5p, which explained the reasons that miR-26a-5p expressed lowest in TNBC.

CONCLUSIONS

Taken together, we reveal the important role of miR-26a-5p in Cisplatin sensitivity and highlight its new mechanism in DNA damage and synthetic lethal.

lncRNA NEAT1 mediates LPS-induced pyroptosis of BEAS-2B cells via targeting miR-26a-5p/ROCK1 axis

Acute lung injury (ALI) is an adverse disease of the respiratory system, and one of its prevalent causes is sepsis induction. Cell pyroptosis facilitates the progression of ALI and lncRNAs play critical roles in ALI. Thus, this research seeks to investigate the specific mechanism of NEAT1 in sepsis-ALI.BEAS-2B cells were exposed to lipopolysaccharide (LPS) to construct a cell model of sepsis-induced ALI. The gene and protein expression were assessed using qRT-PCR and western blot. Cell viability was identified by CCK-8. Cell death was discovered using PI staining. The secretion of IL-1β and IL-18 was examined using ELISA. The interconnections among NEAT1, miR-26a-5p, and ROCK1 were confirmed using starbase, luciferase assay, and RIP.LPS treatment augmented NEAT1 and ROCK1 levels while mitigating miR-26a-5p level in BEAS-2B cells. Additionally, LPS treatment facilitated cell death and cell pyroptosis, whereas NEAT1 silencing could reverse these effects in BEAS-2B cells. Mechanistically, NEAT1 positively mediated ROCK1 expression by targeting miR-26a-5p. Furthermore, miR-26a-5p inhibitor offset NEAT1 depletion-mediated suppressive effects on cell death and cell pyroptosis. ROCK1 upregulation decreased the inhibitory impacts produced by miR-26a-5p overexpression on cell death and cell pyroptosis. Our outcomes demonstrated NEAT1 could reinforce LPS-induced cell death and cell pyroptosis by repressing the miR-26a-5p/ROCK1 axis, thereby worsening ALI caused by sepsis. Our data indicated NEAT1, miR-26a-5p, and ROCK1 might be biomarkers and target genes for relieving sepsis-induced ALI.

Knockdown of Long Noncoding RNA LINC00240 Inhibits Esophageal Cancer Progression by Regulating miR-26a-5p

Background

Esophageal cancer is the most prevalent digestive system tumor. Due to a lack of characteristic symptoms and early diagnosis, a confirmed esophageal cancer is typically detected at a progressively harmful stage. Therefore, it is critical to investigate the molecular mechanisms governing the formation and progression of esophageal cancer in order to identify new treatment targets for esophageal cancer early detection.

Methods

We first screened the differentially expressed gene LINC00240 in the TCGA database. Multivariate analysis and Cox regression were performed, and a nomogram was constructed for internal validation. The correlation between LINC00240 and immune cells was analyzed using the TIMER database. The possible mechanism of action was explored through GSEA enrichment analysis. Then, in 43 esophageal cancer tissues, paracancour tissues, and cell lines, the LINC00240 expression was found. Transwell assays, CCK-8, and clone formation assays were utilized to assess the impact of LINC00240 on the metastasis of esophageal cancer cells. The binding activity of LINC00240 to downstream miRNAs was assessed using the luciferase reporter gene.

Results

TCGA database showed that LINC00240 expression was increased in cancer tissues compared to adjacent tissues. The C-index of the nomogram is 0.712 (0.666-0.758), and the prediction model has good accuracy. According to the TIMER database, the LINC00240 expression is linked to immune infiltration and may be crucial in encouraging the immune escape of tumor cells. Gene enrichment analysis depicts that LINC00240 could influence the biological events of esophageal cancer by taking part in pathways such as affecting the cell cycle. LINC00240 expression was substantially greater in the plasma of esophageal cancer patients (3.94 ± 1.55) than in the normal control group (2.13 ± 0.89). Plasma expression of LINC00240 was linked to the degree of differentiation (P=0.0345) and TNM stage (P=0.0409). Knocked down LINC00240 inhibited esophageal cancer cells proliferation, lone formation, and invasion. LINC00240 might bind itself to miR-26a-5p and influence its expression. MiR-26a-5p inhibitor can dramatically limit the ability of LINC00240 knockdown on plate colony formation and relocation of esophageal cancerous cells was demonstrated in colony formation and migration experiments.

Conclusion

LINC00240 expression is elevated in esophageal cancerous tissues, and knocking down LINC00240 decreases esophageal cancer cell proliferation, clone formation, invasion, and migration via miR-26a-5p. As a result, LINC00240 could be a novel target for esophageal cancer patients' early diagnosis and treatment.

MiR-26a-5p regulates proliferation, apoptosis, migration and invasion via inhibiting hydroxysteroid dehydrogenase like-2 in cervical cancer cell

Background

Evidences have indicated that miR-26a-5p regulates the malignant properties of various tumor cells. However, the influences of miR-26a-5p on proliferation, apoptosis and invasion are still vague in the cervical cancer (CC) cells.

Methods

The miRNA microarray and real-time quantitative PCR (RT-qPCR) analysis were utilized to detect the expression of miR-26a-5p in the patients with CC. Kaplan–Meier plotter was performed to evaluate the overall survival (OS) of the patients with CC. The CCK-8, flow cytometry, transwell and wound healing analyses were respectively used to analyze proliferation, migration and invasion in the CC cells. RT-qPCR, western blot and IHC analysis were executed to measure the expression of hydroxysteroid dehydrogenase like-2 (HSDL2) in the patients with CC. Bioinformatics and luciferase reporter assay were carried out to verify the relationship of miR-26a-5p and HSDL2.

Results

The expression of miR-26a-5p was downregulated and low expression of miR-26a-5p indicated a poor OS in patients with CC. Overexpression of miR-26a-5p significantly inhibited proliferation, migration and invasion, accelerated apoptosis in the Hela and C33A cells. The expression of HSDL2 was upregulated, and negatively correlated with miR-26a-5p in the patients with CC. HSDL2 was directly targeted by miR-26a-5p and rescue experiments displayed that HSDL2 partially abolished proliferation, apoptosis, migration, and invasion induced by miR-26a-5p in CC cells.

Conclusions

MiR-26a-5p alleviated progression of CC by suppressing proliferation, migration and invasion, promoting apoptosis through downregulating HSDL2.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09970-x.

MiR-26a-5p as a useful therapeutic target for upper tract urothelial carcinoma by regulating WNT5A/β-catenin signaling

The role of miRNAs in cancer and their possible function as therapeutic agents are interesting and needed further investigation. The miR-26a-5p had been demonstrated as a tumor suppressor in various cancers. However, the importance of miR-26a-5p regulation in upper tract urothelial carcinoma (UTUC) remains unclear. Here, we aimed to explore the miR-26a-5p expression in UTUC tissues and to identify its regulatory targets and signal network involved in UTUC tumorigenesis. The miR-26a-5p expression was validated by quantitative real-time polymerase chain reaction (qPCR) using renal pelvis tissue samples from 22 patients who were diagnosed with UTUC and 64 cases of renal pelvis tissue microarray using in situ hybridization staining. BFTC-909 UTUC cells were used to examine the effects of miR-26a-5p genetic delivery on proliferation, migration and expression of epithelial-to-mesenchymal transition (EMT) markers. MiR-26a-5p was significantly down-regulated in UTUC tumors compared to adjacent normal tissue and was decreased with histological grades. Moreover, restoration of miR-26a-5p showed inhibition effects on proliferation and migration of BFTC-909 cells. In addition, miR-26a-5p delivery regulated the EMT marker expression and inhibited WNT5A/β-catenin signaling and expression of downstream molecules including NF-κB and MMP-9 in BFTC-909 cells. This study demonstrated that miR-26a-5p restoration may reverse EMT process and regulate WNT5A/β-catenin signaling in UTUC cells. Further studies warranted to explore the potential roles in biomarkers for diagnostics and prognosis, as well as novel therapeutics targets for UTUC treatment.

Identification of lncRNA/circRNA-miRNA-mRNA ceRNA Network as Biomarkers for Hepatocellular Carcinoma

Background: Hepatocellular carcinoma (HCC) accounts for the majority of liver cancer, with the incidence and mortality rates increasing every year. Despite the improvement of clinical management, substantial challenges remain due to its high recurrence rates and short survival period. This study aimed to identify potential diagnostic and prognostic biomarkers in HCC through bioinformatic analysis.

Methods: Datasets from GEO and TCGA databases were used for the bioinformatic analysis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were carried out by WebGestalt website and clusterProfiler package of R. The STRING database and Cytoscape software were used to establish the protein-protein interaction (PPI) network. The GEPIA website was used to perform expression analyses of the genes. The miRDB, miRWalk, and TargetScan were employed to predict miRNAs and the expression levels of the predicted miRNAs were explored via OncomiR database. LncRNAs were predicted in the StarBase and LncBase while circRNA prediction was performed by the circBank. ROC curve analysis and Kaplan-Meier (KM) survival analysis were performed to evaluate the diagnostic and prognostic value of the gene expression, respectively.

Results: A total of 327 upregulated and 422 downregulated overlapping DEGs were identified between HCC tissues and noncancerous liver tissues. The PPI network was constructed with 89 nodes and 178 edges and eight hub genes were selected to predict upstream miRNAs and ceRNAs. A lncRNA/circRNA-miRNA-mRNA network was successfully constructed based on the ceRNA hypothesis, including five lncRNAs (DLGAP1-AS1, GAS5, LINC00665, TYMSOS, and ZFAS1), six circRNAs (hsa_circ_0003209, hsa_circ_0008128, hsa_circ_0020396, hsa_circ_0030051, hsa_circ_0034049, and hsa_circ_0082333), eight miRNAs (hsa-miR-150-5p, hsa-miR-19b-3p, hsa-miR-23b-3p, hsa-miR-26a-5p, hsa-miR-651-5p, hsa-miR-10a-5p, hsa-miR-214-5p and hsa-miR-486-5p), and five mRNAs (CDC6, GINS1, MCM4, MCM6, and MCM7). The ceRNA network can promote HCC progression via cell cycle, DNA replication, and other pathways. Clinical diagnostic and survival analyses demonstrated that the ZFAS1/hsa-miR-150-5p/GINS1 ceRNA regulatory axis had a high diagnostic and prognostic value.

Conclusion: These results revealed that cell cycle and DNA replication pathway could be potential pathways to participate in HCC development. The ceRNA network is expected to provide potential biomarkers and therapeutic targets for HCC management, especially the ZFAS1/hsa-miR-150-5p/GINS1 regulatory axis.

Oxidative Stress and Inflammation in Cardiovascular Diseases and Cancer: Role of Non-coding RNAs

High oxidative stress, Th1/Th17 immune response, M1 macrophage inflammation, and cell death are associated with cardiovascular diseases. Controlled oxidative stress, Th2/Treg anti-tumor immune response, M2 macrophage inflammation, and survival are associated with cancer. MiR-21 protects against cardiovascular diseases but may induce tumor growth by retaining the anti-inflammatory M2 macrophage and Treg phenotypes and inhibiting apoptosis. Down-regulation of let-7, miR-1, miR-9, miR-16, miR-20a, miR-22a, miR-23a, miR-24a, miR-26a, miR-29, miR-30a, miR-34a, miR-124, miR-128, miR-130a, miR-133, miR-140, miR-143-145, miR-150, miR-153, miR-181a, miR-378, and miR-383 may aid cancer cells to escape from stresses. Upregulation of miR-146 and miR-223 may reduce anti-tumor immune response together with miR-21 that also protects against apoptosis. MiR-155 and silencing of let-7e, miR-125, and miR-126 increase anti-tumor immune response. MiR expression depends on oxidative stress, cytokines, MYC, and TGF-β, and expression of silencing lncRNAs and circ-RNAs. However, one lncRNA or circ-RNA may have opposite effects by targeting several miRs. For example, PVT1 induces apoptosis by targeting miR-16a and miR-30a but inhibits apoptosis by silencing miR-17. In addition, levels of a non-coding RNA in a cell type depend not only on expression in that cell type but also on an exchange of microvesicles between cell types and tumors. Although we got more insight into the function of a growing number of individual non-coding RNAs, overall, we do not know enough how several of them interact in functional networks and how their expression changes at different stages of disease progression.

miR-26a-5p protects against drug-induced liver injury via targeting bid

BACKGROUNDS

miR-26a-5p is a short noncoding RNA that is abnormally expressed in drug-induced liver injury (DILI), but its pathophysiologic role in the mechanism of disease in DILI is still vague.

METHODS

The expression of miR-26a-5p, viability of hepatic stellate cells (HSCs) proliferation, and apoptosis were explored via real-time PCR, CCK-8 assay, Tunel fluorescence, and flow cytometry. The expression of Bid was detected via Western blot assays, real-time PCR, and immunofluorescence. The apoptosis-associated proteins were determined through Western blot. The interaction between miR-26a-5p and Bid was measured via Dual luciferase reporter assay.

RESULTS

miR-26a-5p expression was greatly decreased in HSCs and serum treated with azithromycin, simvastatin and diclofenac sodium, respectively. Hepatocyte viability was largely suppressed while hepatocyte apoptosis was markedly increased in DILI. Correspondingly, the apoptosis-associated proteins including Bid, caspase-8 and cytochrome C in HSCs were significantly upregulated when treated with either of these drugs. Moreover, miR-26a-5p interacted with Bid, and hepatocyte proliferation and apoptosis influenced by miR-26a-5p mimics were obviously reversed when co-treated with overexpressed Bid plasmids.

CONCLUSIONS

miR-26a-5p played a protective role against DILI via targeting Bid.

STK39 enhances the progression of Cholangiocarcinoma via PI3K/AKT pathway

Serine/threonine kinase 39 (STK39) is overexpressed in various tumor tissues and plays an essential role in tumor progression. In this study, we investigated the clinical value, as well as the potential functions and mechanisms of STK39 in cholangiocarcinoma (CCA). The results showed that STK39 was overexpressed in CCA and negatively associated with the prognosis of patients with CCA. Functionally, STK39 knockdown suppressed cell proliferation, migration, and invasion, while STK39 overexpression facilitated tumor aggressiveness. The tumor-promoting effects of STK39 in CCA were also validated by in vivo experiments. Mechanistically, RNA-seq analysis identified that STK39 enhanced the progression of CCA by activating PI3K/AKT signaling pathway. Furthermore, overexpression of STK39 could induce gemcitabine resistance in CCA cells. Moreover, the increased expression of STK39 may be mediated by the dysregulation of miR-26a-5p. In summary, STK39 could be served as a valuable prognostic candidate and a potential therapeutic target of CCA.

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STK39 was overexpressed in CCA, negatively associated with the prognosis of patients with CCA

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STK39 knockdown suppressed cell proliferation and invasion. STK39 overexpression facilitated tumor aggressiveness

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STK39 mediates oncogenic effects on CCA cells by activating the PI3K/AKT signaling pathway

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STK39 reduces CCA sensitivity to gemcitabine. Increased expression of STK39 may be mediated by dysregulation of miR-26a-5p

A Set of 17 microRNAs Common for Brain and Cerebrospinal Fluid Differentiates Primary Central Nervous System Lymphoma from Non-Malignant Brain Tumors

The diagnosis of primary central nervous system (CNS) lymphoma, which is predominantly of the diffuse large B-cell lymphoma type (CNS DLBCL), is challenging. MicroRNAs (miRs) are gene expression-regulating non-coding RNAs that are potential biomarkers. We aimed to distinguish miR expression patterns differentiating CNS DLBCL and non-malignant CNS diseases with tumor presentation (n-ML). Next generation sequencing-based miR profiling of cerebrospinal fluids (CSFs) and brain tumors was performed. Sample source-specific (CSF vs. brain tumor) miR patterns were revealed. Even so, a set of 17 miRs differentiating CNS DLBCL from n-ML, no matter if assessed in CSF or in a tumor, was identified. Along with the results of pathway analyses, this suggests their pathogenic role in CNS DLBCL. A combination of just four of those miRs (miR-16-5p, miR-21-5p, miR-92a-3p, and miR-423-5p), assessed in CSFs, discriminated CNS DLBCL from n-ML samples with 100% specificity and 67.0% sensitivity. Analyses of paired CSF-tumor samples from patients with CNS DLBCL showed significantly lower CSF levels of miR-26a, and higher CSF levels of miR-15a-5p, miR-15b-5p, miR-19a-3p, miR-106b-3p, miR-221-3p, and miR-423-5p. Noteworthy, the same miRs belonged to the abovementioned set differentiating CNS DLBCL from non-malignant CNS diseases. Our results not only add to the basic knowledge, but also hold significant translational potential.

Silencing the lncRNA NORAD inhibits EMT of head and neck squamous cell carcinoma stem cells via miR‑26a‑5p

Cancer stem cells are closely associated with tumor metastasis or recurrence. According to previous literature reports, microRNA (miR)‑26a has an inhibitory effect on head and neck squamous cell carcinoma (HNSCC), and the long non‑coding RNA (lncRNA) non‑coding RNA activated by DNA damage (NORAD) has been found to interact with miR‑26a‑5p. The present study aimed to investigate the regulation and mechanism of NORAD and miR‑26a‑5p in the epithelial‑mesenchymal transition (EMT) of HNSCC stem cells. An ALDEFLUOR stem cell detection kit, a flow cytometer, a self‑renewal ability test and western blotting were used to sort and identify HNSCC stem cells. The ENCORI website and a dual‑luciferase assay were used to assess the relationship between genes. The mRNA and protein expression levels of NORAD, miR‑26a‑5p and EMT‑related genes were detected via reverse transcription‑quantitative PCR and western blotting. Functional experiments (MTT assay, flow cytometry, wound healing assay and Transwell assay) were conducted to analyze the effects of NORAD and miR‑26a‑5p on HNSCC stem cells. The successfully sorted aldehyde dehydrogenase (ALDH)⁺ cells had a self‑renewal capacity and displayed upregulated expression levels of CD44, Oct‑4 and Nanog. NORAD knockdown, achieved using small interfering (si)RNA, downregulated the expression levels of tumor markers in ALDH⁺ cells. siNORAD inhibited cell vitality, migration and invasion, as well as promoted apoptosis, increased the expression of epithelial cell markers and decreased the expression of interstitial cell markers in HNSCC stem cells. miR‑26a‑5p was a downstream gene of NORAD, and knockdown of miR‑26a‑5p partially offset the regulatory effect of siNORAD on HNSCC stem cells. Collectively, the present study demonstrated that NORAD knockdown attenuated the migration, invasion and EMT of HNSCC stem cells via miR‑26a‑5p.

Learning from Embryogenesis-A Comparative Expression Analysis in Melanoblast Differentiation and Tumorigenesis Reveals miRNAs Driving Melanoma Development

Malignant melanoma is one of the most dangerous tumor types due to its high metastasis rates and a steadily increasing incidence. During tumorigenesis, the molecular processes of embryonic development, exemplified by epithelial-mesenchymal transition (EMT), are often reactivated. For melanoma development, the exact molecular differences between melanoblasts, melanocytes, and melanoma cells are not completely understood. In this study, we aimed to identify microRNAs (miRNAs) that promote melanoma tumorigenesis and progression, based on an in vitro model of normal human epidermal melanocyte (NHEM) de-differentiation into melanoblast-like cells (MBrCs). Using miRNA-sequencing and differential expression analysis, we demonstrated in this study that a majority of miRNAs have an almost equal expression level in NHEMs and MBrCs but are significantly differentially regulated in primary tumor- and metastasis-derived melanoma cell lines. Further, a target gene analysis of strongly regulated but functionally unknown miRNAs yielded the implication of those miRNAs in many important cellular pathways driving malignancy. We hypothesize that many of the miRNAs discovered in our study are key drivers of melanoma development as they account for the tumorigenic potential that differentiates melanoma cells from proliferating or migrating embryonic cells.

miRNA-218-5p increases cell sensitivity by inhibiting PRKDC activity in radiation-resistant lung carcinoma cells

BACKGROUND

Non-small cell lung carcinoma (NSCLC) is a malignancy with the highest mortality rate. Currently, surgery combined with radiotherapy is the first choice in the clinical treatment of lung carcinoma (LC); however, long-term radiotherapy leads to radiation resistance in patients, resulting in treatment failure.

METHODS

In this study, a new microRNA-218-5p (miRNA-218-5p) was identified, and its function in LC was investigated.

RESULTS

Reverse transcription quantitative polymerase chain reaction (RT-qPCR) results revealed that miRNA-218-5p was downregulated in LC. Overexpression or inhibition of miRNA-218-5p in LC and targeted binding of protein kinase, DNA-activated, catalytic polypeptide (PRKDC) to miRNA-218-5p were confirmed by comprehensive bioinformatic analysis. Exosomes from A549 and H1299 cells were cocultured with miRNA-218-5p and then cotransfected into radiation-resistant A549R and H1299R cells; the proliferation of radiation-resistant LC cells was found to be effectively inhibited and apoptosis was induced. Overexpression of miRNA-218-5p and X-irradiation could enhance the radiosensitivity of LC cells. Exogenous miRNA-218-5p derived from A549 and H1299 cells could be transfected into radiation-resistant LC cells and could inhibit PRKDC expression, thus accelerating DNA damage, apoptosis, and radiation sensitization of LC cells.

CONCLUSIONS

miRNA-218-5p could induce apoptosis and enhance the radiosensitivity of LC cells through regulatory activities, thus suggesting its application as a potential target for LC treatment.

MicroRNA-26a inhibits cell proliferation and invasion by targeting FAM98A in breast cancer

MicroRNAs (miRNAs/miRs) play key roles in cancer progression. Extensive research has revealed that miR-26a is abnormally expressed and functions as a tumor suppressor in numerous types of cancer. Thus, the present study was undertaken to investigate the regulatory role and potential mechanism of action of miR-26a in breast cancer. Furthermore, the present study aimed to examine the alterations in miR-26a expression and its effects on human breast cancer cells. Reverse transcription-quantitative PCR was conducted to assess the differences in miR-26a expression between human breast cancer and normal breast specimens. A Cell Counting Kit-8 assay and cloning experiments were used to detect cell proliferation and clone formation. Wound healing and Transwell assays were performed to examine cell migration and invasion. A luciferase activity experiment was utilized to validate the association between miR-26a and family with sequence similarity 98 member A (FAM98A). Western blotting was conducted to detect the protein expression levels of FAM98A, sonic hedgehog signaling molecule (SHH), smoothened, frizzled class receptor (SMO) and GLI family zinc finger 1 (GLI1). The results indicated that miR-26a expression was decreased in breast carcinoma tissues and cell lines. Moreover, overexpression of miR-26a significantly suppressed cell proliferation, clone formation ability and metastasis, and it sensitized breast cancer cells to docetaxel. It was demonstrated that miR-26a directly targeted FAM98A, and that FAM98A, SHH, SMO and GLI1 expression levels were decreased in cells transfected with miR-26a mimics. Collectively, the results of the present study suggested that miR-26a negatively regulated the expression of FAM98A, indicating that it may play a key role in the suppression of breast carcinogenesis.

Formononetin ameliorates the drug resistance of Taxol resistant triple negative breast cancer by inhibiting autophagy

Characterized by autophagy-associated protein disorders, autophagy participates in Taxol resistance in triple negative breast cancer (TNBC). As an evolutionarily conserved serine/threonine protein kinase with complex signaling pathway, mammalian target of rapamycin (mTOR) can regulate various cellular functions by phosphorylation of its downstream target proteins after activation. A large number of references have demonstrated that mTOR signaling pathway is related to autophagy and apoptosis. Formononetin (FMNT) has anticancer properties against breast, prostate and colon cancers. This study aimed to explore the regulatory effect of FMNT/miR-199a-3p/mTOR pathway on Taxol resistance and autophagy in breast cancer (BC). MiR-199a-3p, mTOR, LC3 and other autophagy related proteins were detected in Taxol sensitive and Taxol resistant TNBC cell lines, which were MDA-MB-231 and MDA-MB-231/Taxol, respectively. Cell viability and toxicity were determined by CCK-8 and MTT assay, respectively. The therapeutic effect of FMNT was evaluated in xenotransplantation model of nude mice. MiR-199a-3p was more highly expressed in MDA-MB-231/Taxol than in MDA-MB-231, while mTOR and p-mTOR decreased in MDA-MB-231/Taxol in comparison with MDA-MB-231, and autophagy activation and drug resistance were enhanced. In MDA-MB-231/Taxol cell line, the role of FMNT was verified to inhibit high miR-199a-3p expression. In addition, the combination therapy of FMNT and Taxol was found to be more effective in inhibiting autophagy and drug resistance. Moreover, mTOR was the target of miR-199a-3p, which was confirmed by dual luciferase reporter (DLR) gene assay. Oral administration of FMNT reduced tumor volume after MDA-MB-231/Taxol injection in vivo. Moreover, oral administration of FMNT and Taxol suppressed autophagy and Taxol resistance by restoring mTOR protein level to that of the parent MDA-MB-231, suggesting that miR-199a-3p can severe as a new target to overcome Taxol resistance in TNBC.

Up-Regulation of miR-26a-5p Inhibits E2F7 to Regulate the Progression of Renal Carcinoma Cells

Background

Metastasis is the main cause of renal cell carcinoma (RCC) tumor death, and effective inhibition of RCC metastasis is an essential means to meliorate the prognosis of RCC patients. MicroRNAs (miRs) have been proved to be stable and important biomarkers for several malignancies. This study is therefore set out to explore the metastasis-related miR and its mechanism in RCC.

Methods

The expression of miR- 26a -5p in RCC was analyzed using the expression profile in the Cancer Genome Atlas (TCGA). MiR-26a-5p and E2F transcription factor 7 (E2F7) in RCC patients were detected by qRT-PCR. Cell Counting Kit-8 (CCK-8) was adopted to assess cell proliferation, Transwell was utilized to evaluate migration and invasion, and flow cytometry (FC) was used to determine apoptosis. Mouse cell-derived and patient-derived xenotransplantation models were established to evaluate the effect of miR-26a-5p on tumor growth and metastasis in vivo. The molecular mechanism of miR-26a-5p was analyzed by dual-luciferase reporter (DLR) gene analysis, qRT-PCR, and Western blot (WB) both in vivo and in vitro.

Results

MiR-26a-5p was reduced in renal carcinoma cells and may serve as a biomarker for renal cancer metastasis and prognosis. MiR-26a-5p up-regulation inhibited migration and invasion in renal cell lines and tumor metastasis in vivo. Bioinformatics target prediction and RNA-seq results showed that E2F7 was among the targets of miR-26a-5p and was significantly inhibited by miR-26a-5p in vivo and in vitro.

Conclusion

MiR-26a-5p presents low expression in RCC and promotes RCC cell apoptosis and prevents cells from proliferating and invading by targeting E2F7, which is a promising therapeutic target for RCC.