MicroRNA-224 aggrevates tumor growth and progression by targeting mTOR in gastric cancer

The strict regulation of HIF-1α by non-coding RNAs: new insight towards proliferation, metastasis, and therapeutic resistance strategies

The hypoxic environment is prominently witnessed in most solid tumors and is associated with the promotion of cell proliferation, epithelial-mesenchymal transition (EMT), angiogenesis, metabolic reprogramming, therapeutic resistance, and metastasis of tumor cells. All the effects are mediated by the expression of a transcription factor hypoxia-inducible factor-1α (HIF-1α). HIF-1α transcriptionally modulates the expression of genes responsible for all the aforementioned functions. The stability of HIF-1α is regulated by many proteins and non-coding RNAs (ncRNAs). In this article, we have critically discussed the crucial role of ncRNAs [such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), Piwi-interacting RNAs (piRNAs), and transfer RNA (tRNA)-derived small RNAs (tsRNAs)] in the regulation of stability and expression of HIF-1α. We have comprehensively discussed the molecular mechanisms and relationship of HIF-1α with each type of ncRNA in either promotion or repression of human cancers and therapeutic resistance. We have also elaborated on ncRNAs that are in clinical examination for the treatment of cancers. Overall, the majority of aspects concerning the relationship between HIF-1α and ncRNAs have been discussed in this article.

The role of microRNA-induced apoptosis in diverse radioresistant cancers

Resistance to cancer radiotherapy is one of the biggest concerns for success in treating and preventing recurrent disease. Malignant tumors may develop when they block genetic mutations associated with apoptosis or abnormal expression of apoptosis; Tumor treatment may induce the expression of apoptosis-related genes to promote tumor cell apoptosis. MicroRNAs have been shown to contribute to forecasting prognosis, distinguishing between cancer subtypes, and affecting treatment outcomes in cancer. Constraining these miRNAs may be an attractive treatment strategy to help overcome radiation resistance. The delivery of these future treatments is still challenging due to the excess downstream targets that each miRNA can control. Understanding the role of miRNAs brings us one step closer to attaining patient treatment and improving patient outcomes. This review summarized the current information on the role of microRNA-induced apoptosis in determining the radiosensitivity of various cancers.

Silencing of integrin subunit α3 inhibits the proliferation, invasion, migration and autophagy of esophageal squamous cell carcinoma cells

Esophageal squamous cell carcinoma (ESCC) is a deadly disease that seriously affects global public health. The aim of the present study was to explore the role of integrin subunit α3 (ITGA3) in ESCC and investigate its detailed molecular mechanisms. Using reverse transcription–quantitative PCR (RT-qPCR) and western blotting, the mRNA and protein expression of ITGA3 in cell lines was detected. In addition, a series of cellular biological experiments, including Cell Counting Kit-8, wound-healing, Transwell and TUNEL assays, were used to evaluate proliferation, migration, invasion and apoptosis, respectively. Furthermore, western blotting was used to measure the expression of corresponding proteins. ITGA3 was found to be upregulated in ESCC cell lines (ECA109 and TE1). It was also found that ITGA3 silencing inhibited the proliferation, migration, invasion and autophagy of ECA109 and TE1 cells but promoted their apoptosis. In addition, ITGA3 silencing was found to inhibit the FAK/PI3K/AKT signaling pathway. In conclusion, ITGA3 knockdown suppressed cell proliferation, invasion, migration and autophagy in ECA109 and TE1 cells, suggesting that ITGA3 may be a potential therapeutic target for the treatment of ESCC.

Role of microRNAs in the anticancer effects of the flavonoid luteolin: a systematic review

Flavonoids, a broad class of polyphenolic compounds, can potentially have several therapeutic properties in human diseases, including protective effects against oxidative stress, inflammation, cardiovascular disease, diabetes, neurodegenerative disorders, and cancers. Luteolin as a member of flavonoids has been found to exhibit several anticancer properties mainly through cell apoptosis induction, inhibition of invasion, cell proliferation, network formation, and migration. Recent studies have revealed that phytochemicals such as luteolin may exert therapeutic properties through microRNAs (miRNAs or miRs), which have been emerged as important molecules in cancer biology in recent years. miRNAs, as a class of noncoding RNAs, have several important roles in cancer progression or regression. In this review, we aimed to summarize and discuss the role of miRNAs in the luteolin effects on different cancers. This review can be in line with the studies, which have shown that miRNAs may be potential therapeutic targets in cancer treatment.

miR-224-5p Contained in Urinary Extracellular Vesicles Regulates PD-L1 Expression by Inhibiting Cyclin D1 in Renal Cell Carcinoma Cells

The abundant miRNAs in urinary extracellular vesicles (EVs) represent ideal reservoirs for biomarker discovery, especially in renal cell carcinoma (RCC). However, the content and biological functions of microRNAs contained in urinary EVs in RCC remain ambiguous. In this study, urinary EVs were isolated and characterized from RCC patients and healthy volunteers. Differentially expressed microRNAs in urinary EVs were screened by small RNA sequencing. The target gene and biological functions of selected microRNAs were investigated through multifaceted methods. Results indicated that miR-224-5p was significantly upregulated in urinary EVs of RCC patients compared to healthy volunteers. The overexpression of miR-224-5p inhibited RCC cell proliferation and induced cell cycle arrest. The gene CCND1 encoding cyclin D1 was identified as a direct target of miR-224-5p via prediction and validation. Moreover, the invasive and metastatic abilities of RCC cells were enhanced by miR-224-5p. Interestingly, miR-224-5p also increased the stability of PD-L1 protein by inhibiting CCND1. This effect could be transmitted via EVs and further promoted the resistance of RCC cells to T cell-dependent toxicity. In summary, urinary EVs containing miR-224-5p were identified as a potential biomarker in RCC. Regulation of PD-L1 protein expression by miR-224-5p through suppressing CCND1 elucidates new roles of miR-224-5p in RCC progression.

LINC00619 restricts gastric cancer progression by preventing microRNA-224-5p-mediated inhibition of OPCML

Several long intergenic noncoding RNAs (lincRNAs) have been linked to carcinogenesis; however, little is known about the role of LINC00619 in gastric cancer (GC). LINC00619 was identified among differentially expressed lncRNAs linked to gastric cancer based on microarray analysis and its relationships with miR-224-5p and opioid binding protein/cell adhesion molecule-like gene (OPCML) were investigated. LINC00619, miR-224-5p, and OPCML expression were measured in GC tissues and cells. Ectopic expression and depletion experiments were conducted to assess the effects of LINC00619, miR-224-5p and OPCML on cell proliferation, invasion, migration and apoptosis as well as their effects on the expression of apoptosis- and metastasis-related genes (Bcl-2, Bax, MMP-2 and MMP-9). Tumorigenicity in the nude mice was also examined. Gastric cancer was characterized by downregulation of LINC00619 and OPCML and upregulation of miR-224-5p. Additionally, we found that miR-224-5p could interact with both LINC00619 and OPCML. Upregulation of LINC00619, which binds to miR-224-5p, led to decreased miR-224-5p expression while increasing the expression of OPCML, a target gene of miR-224-5p. Overexpression of LINC00619 or OPCML or downregulation of miR-224-5p suppressed cell proliferation, invasion, migration and tumorigenicity while promoting apoptosis in GC. Our results indicated that LINC00619 functions as a tumor suppressor in GC by impairing miR-224-5p-mediated inhibition of OPCML.

CircPCMTD1 Acts as the Sponge of miR-224-5p to Promote Glioma Progression

Glioma is the most common malignant tumor of the central nervous system with high morbidity and mortality. Circular RNAs (circRNAs) are abundant non-coding RNAs, which contribute to tumor progression by competing with other endogenous RNAs such as microRNA (miRNA). MiRNA are a class of small non-coding RNAs, which interrupt the translation of target mRNAs. CircPCMTD1 (hsa-circ-0001801) is a newly discovered circRNA that was found to be significantly upregulated in glioma. However, its function is unclear. In this study, circPCMTD1 upregulation promoted the cell viability, migration and invasion dramatically, while the inhibition of circPCMTD1 led to a significant reduction of tumor growth in vivo. MiRNAs microarray analyses on circPCMTD1 silencing models in U251 and U118MG cells were performed, and the results suggested that circPCMTD1 knockdown could upregulate the expression of miR-224-5p and downregulate the expression of mTOR, one of miR-224-5p targets, in both cell lines. According to the prediction from circular RNA interactome and Targetscan, there was a complementary sequence in circPCMTD1 for miR-224-5p. Dual-luciferase reporter assay demonstrated that circPCMTD1 were targets of miR-224-5p. RIP assay was also performed to further confirm their directly interaction. Overexpression of miR-224-5p inhibited the viability and proliferation, migration, and invasion of U251 and U118MG glioma cells. In conclusion, circPCMTD1 could contribute to the promotion of glioma progression, and it may serve as the sponge of miR-224-5p to exert its function.

KRT15, INHBA, MATN3, and AGT are aberrantly methylated and differentially expressed in gastric cancer and associated with prognosis

AIM

The present study aims to identify aberrantly methylated and differentially expressed genes (DEGs) in gastric cancer (GC) and explore their potential role in the carcinogenesis and development of GC.

METHODS

The original RNA-Seq, clinical information and Illumina Human Methylation 27 Chip data associated with GC were downloaded from The Cancer Genome Atlas (TCGA) database using the gdc-client tool. The DEGs and aberrantly methylated genes (AMGs) were screened with edgeR and limma package in R, respectively. The cut-off criteria for DEG identification were P < 0.05 and fold change (FC) >2.0, and for AMG identification were P < 0.05 and |t|>2.0. Genes which were both DEGs and AMGs were considered to be regulated by aberrant DNA methylation in GC. The common genes were used for further functional enrichment analysis in the categories of cellular component, molecular function, biological process and biological pathway.

RESULTS

In total 465 genes including 336 down-regulated genes with hyper-methylation (DGs-Hyper) and 129 up-regulated genes with hypo-methylation (UGs-Hypo) were identified. Cellular component analysis showed that these genes were mainly expressed in the cytoplasm and plasma membrane. Molecular function and biological process analysis indicated that the genes primarily participate in cell communication, signal transduction, cell growth/maintenance and function as transcription factors, receptor, cell adhesion molecules, and transmembrane receptor protein tyrosine kinases. Biological pathway analysis revealed that the genes are involved in some crucial pathways including epithelial-to-mesenchymal transition, IL3-mediated signaling, mTOR signaling, VEGF/VEGFR and c-Met signaling. KRT15, INHBA, MATN3, and AGT are significantly associated with the prognosis of GC patients.

CONCLUSION

Our study identified several DEGs regulated by aberrant DNA methylation in GC. The mechanism of DNA methylation in the carcinogenesis and development of GC could be further explored in these genes, especially KRT15, INHBA, MATN3, and AGT.

miR-92b-3p-TSC1 axis is critical for mTOR signaling-mediated vascular smooth muscle cell proliferation induced by hypoxia

Pulmonary artery smooth muscle cells (PASMCs) undergo proliferation by the mammalian target of rapamycin (mTOR) signaling pathway under hypoxia. Hypoxia induces expression of a specific set of microRNAs (miRNAs) in a variety of cell types. We integrated genomic analyses of both small non-coding RNA and coding transcripts using next-generation sequencing (NGS)-based RNA sequencing with the molecular mechanism of the mTOR signaling pathway in hypoxic PASMCs. These analyses revealed hypoxia-induced miR-92b-3p as a potent regulator of the mTOR signaling pathway. We demonstrated that miR-92b-3p directly targets the 3′-UTR of a negative regulator in the mTOR signaling pathway, TSC1. mTOR signaling and consequent cell proliferation were promoted by enforced expression of miR-92b-3p but inhibited by knocking down endogenous miR-92b-3p. Furthermore, inhibition of miR-92b-3p attenuated hypoxia-induced proliferation of vascular smooth muscle cells (VSMCs). Therefore, this study elucidates a novel role of miR-92b-3p as a hypoxamir in the regulation of the mTOR signaling pathway and the pathological VSMC proliferative response under hypoxia. These findings will help us better understand the miRNA-mediated molecular mechanism of the proliferative response of hypoxic VSMCs through the mTOR signaling pathway.

Protective effect of microRNA-224 on acute lower extremity ischemia through activation of the mTOR signaling pathway via CHOP in mice

Acute lower extremity ischemia (ALEXI) is known worldwide as an urgent condition, occurring when there is an abrupt interruption in blood flow into an extremity. This study aims to investigate whether microRNA-224 (miR-224) affects the ALEXI mice and the underlying mechanism. The miR-224 expression and C/EBP homologous protein (CHOP), mammalian target of rapamycin (mTOR), translation initiation factor 4E-binding protein 1 (4E-BP1), and phosphoprotein 70 ribosomal protein S6 kinase (p70S6K) messenger RNA (mRNA), as well as protein expressions, were determined. The target gene of miR-224 was also verified by using a luciferase reporter gene assay. The vascular endothelial cells from the ALEXI mice were transfected with miR-224 mimics, miR-224 inhibitors, or small-interfering RNA against CHOP. Cell proliferation was assessed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The cell cycle distribution along with the cell apoptosis were both evaluated by using a flow cytometry. The muscle fibers of the lower extremities found in the ALEXI mice were evidently swollen and rounded, presenting with a remarkably narrowed gap. The positive CHOP expression increased in ALEXI mice than normal mice, while the miR-224 expression and mTOR, 4E-BP1, and p70S6K mRNA, as well as the protein expression, decreased. Luciferase reporter gene assay validated that the miR-224 gene directly targeted CHOP. MiR-224 facilitated cell proliferation but inhibited cell apoptosis; by contrast, CHOP increased cell apoptosis. Moreover, the cells transfected along with miR-224 mimic exhibited a lower CHOP expression as well as increased mTOR, 4E-BP1, and p70S6K expression. Our study provided evidence that miR-224 could alleviate the occurrence and development of ALEXI in mice through activation of the mTOR signaling pathway by downregulating CHOP.

Luteolin exerts an anticancer effect on gastric cancer cells through multiple signaling pathways and regulating miRNAs

Accumulating studies confirmed that luteolin, a common dietary flavonoid which is widely distributed in plants and has diverse beneficial biological function, including anti-oxidant, anti-inflammation and anticancer properties. However, the detail mechanisms of luteolin on GC are poorly understood. Here, we investigated the anticancer effect of luteolin in GC cells in vitro and in vivo. Luteolin reduced the cell viability in a time and dose-dependent manner. Luteolin significantly inhibited cell cycle progress, colony formation, proliferation, migration, invasion and promoted apoptosis in vitro and in vivo. Luteolin also regulated these biological effects associated regulators. Mechanically, luteolin treatment regulated Notch1, PI3K, AKT, mTOR, ERK, STAT3 and P38 signaling pathways and modulated a series of miRNAs expression. These findings provide novel insight into the molecular function of luteolin which suggest its potential as a therapeutic agent for human GC.

miR-224 enhances invasion and metastasis by targeting HOXD10 in non-small cell lung cancer cells

Increasing number of studies have indicated aberrant microRNA (miRNA) expression could affect normal biological progress in non-small cell lung cancer (NSCLC) cells. This study was performed to evaluate the biologic functions of microRNA-224 (miR-224) in NSCLC. Real-time PCR was performed to evaluate the expression of miR-224 and Homeobox D10 (HOXD10) in NSCLC cell lines and tissues. Transwell assays were performed to investigate the function of miR-224 on NSCLC cell migration and invasion. Moreover, western blotting and luciferase assays were used to investigate HOXD10 as miR-224 downstream targets. miR-224 is increased in NSCLC metastatic tissues and cell lines. Increased miR-224 expression promoted NSCLC cell migration and invasion, while low miR-224 expression suppressed NSCLC cell migration and invasion. Furthermore, HOXD10 was targeted directly by miR-224 in NSCLC cells. Moreover, we found that HOXD10 was a functional target and influenced tumour-inductive functions of miR-224 on progression of NSCLC. These findings suggest that miR-224 may be used in the treatment of NSCLC. Targeting this novel strategy, miR-224/HOXD10 axis may be helpful as promising biomarker and therapeutic method to control NSCLC cell metastasis.

mTOR signaling-related MicroRNAs and Cancer involvement

MicroRNAs (miRNAs) are a class of single-stranded RNAs, 18-23 nucleotides in length that regulate gene expression at the post-transcriptional level. Dysregulation of miRNAs has been closely associated with the development of cancer. In the process of tumorigenesis, mammalian target of rapamycin (mTOR) plays important roles, and the mTOR signaling pathway is aberrant in various types of human cancers, including non-small cell lung cancer (NSCLC), breast cancer, prostate cancer, as well as others. However, the relationship between miRNAs and the mTOR signaling pathway is indistinct. Herein, we not only summarize the progress of miRNAs and the mTOR signaling pathway in cancers, but also highlight their role in the diagnosis and treatment in the clinic.

Predictive relevance of miR-34a, miR-224 and miR-342 in patients with advanced squamous cell carcinoma of the lung undergoing palliative chemotherapy

Attributing to their pathophysiological role and stability in biological samples, microRNAs (miRNAs) have the potential to become valuable predictive markers for non-small cell lung cancer (NSCLC). Samples of biopsy tissue constitute suitable material for miRNA profiling with the aim of predicting the effect of palliative chemotherapy. The present study group included 81 patients (74 males, 7 females, all smokers or former smokers) with the squamous cell carcinoma (SCC) histological subtype of NSCLC at a late stage (3B or 4). All patients received palliative chemotherapy based on platinum derivatives in combination with paclitaxel or gemcitabine. The expression of 17 selected miRNAs was measured by reverse transcription-quantitative polymerase chain reaction in tumor tissue macrodissected from formalin-fixed paraffin-embedded (FFPE) tissue samples. To predict the effect of palliative chemotherapy, the association between gene expression levels and overall survival (OS) time was analyzed. From the 17 miRNAs of interest, low expression levels of miR-342 and high expression levels of miR-34a and miR-224 were associated with a reduced OS time in subgroups of patients based on smoking status and treatment modality. Using cluster analysis, associations between combinations of miR-34a, -224 and -342 expression levels with patient survival were identified. The present study revealed that patients with the simultaneous high expression of miR-224 and -342 had a similar prognostic outcome to those with the low expression of miR-224 and -342, which was significantly reduced, compared with patients exhibiting high expression of either miR-224 or miR-342 with low expression of the other. We hypothesize that the effect of a particular miRNA is dependent on the expression level of other members of the miRNA network. This finding appears to complicate survival analyses based on individual miRNAs as markers. In conclusion, the present study provides evidence that specific miRNAs were associated with OS time, which may be candidate predictors for the effectiveness of palliative treatment in SCC lung cancer patients. This objective can be better achieved by combining more markers together than by using individual miRNAs.

Prognostic value of microRNAs in gastric cancer: a meta-analysis

BACKGROUND

Previous articles have reported that expression levels of microRNAs (miRNAs) are associated with survival time of patients with gastric cancer (GC). A systematic review and meta-analysis was performed to study the outcome of it.

DESIGN

Meta-analysis.

METHODS

English studies estimating expression levels of miRNAs with any of survival curves in GC were identified up till March 19, 2017 through performing online searches in PubMed, EMBASE, Web of Science and Cochrane Database of Systematic Reviews by two authors independently. The pooled hazard ratios (HR) with 95% confidence intervals (CI) were used to estimate the correlation between miRNA expression and overall survival (OS).

RESULTS

Sixty-nine relevant articles about 26 miRNAs with 6148 patients were ultimately included. GC patients with high expression of miR-20b (HR=2.38, 95%CI=1.16-4.87), 21 (HR=1.77, 95%CI=1.01-3.08), 106b (HR=1.84, 95%CI=1.15-2.94), 196a (HR=2.66, 95%CI=1.94-3.63), 196b (HR=1.67, 95%CI=1.38-2.02), 214 (HR=1.84, 95%CI=1.27-2.67) or low expression of miR-125a (HR=2.06, 95%CI=1.26-3.37), 137 (HR=3.21, 95%CI=1.68-6.13), 141 (HR=2.47, 95%CI=1.34-4.56), 145 (HR=1.62, 95%CI=1.07-2.46), 146a (HR=2.60, 95%CI=1.63-4.13), 206 (HR=2.85, 95%CI=1.73-4.70), 218 (HR=2.61, 95%CI=1.74-3.92), 451 (HR=1.73, 95%CI=1.19-2.52), 486-5p (HR=2.45, 95%CI=1.65-3.65), 506 (HR=2.07, 95%CI=1.33-3.23) have significantly poor OS (P<0.05).

CONCLUSIONS

In summary, miR-20b, 21, 106b, 125a, 137, 141, 145, 146a, 196a, 196b, 206, 214, 218, 451, 486-5p and 506 demonstrate significantly prognostic value. Among them, miR-20b, 125a, 137, 141, 146a, 196a, 206, 218, 486-5p and 506 are strong biomarkers of prognosis in GC.

Tetramethylpyrazine inhibits prostate cancer progression by downregulation of forkhead box M1

Tetramethylpyrazine (TMP) has exhibited various anticancer effects. However, its ability to inhibit proliferation, migration, and invasion of prostate cancer (PCa) PC-3 cells is still unclear. In the present study, different concentrations of TMP were co-incubated with PC-3 cells. The pcDNA-FOXM1 plasmid was transfected into cells before treatment with 500 µg/l TMP. The proliferative, migratory and invasive abilities of PC-3 cells were tested by MTT assay, wound healing assay and colony formation assay. Western blotting was used to investigate the expression of FOXM1. We found that, compared with the control, the proliferative, migratory and invasive abilities of PC-3 cells were decreased after incubation with different concentrations of TMP (P<0.01). The expression of FOXM1 was decreased in TMP-treated PC-3 cells (P<0.01). In addition, overexpression of FOXM1 reversed TMP-mediated inhibition of proliferation, migration and invasion of PC-3 cells. We also found that TMP inhibited PCa growth in vivo in a dose-dependent manner. These results suggest that TMP inhibits PC-3 cell proliferation, migration and invasion by downregulation of FOXM1.

Tanshinone IIA suppresses gastric cancer cell proliferation and migration by downregulation of FOXM1

Tanshinone IIA (TSN) exhibits a variety of anticancer effects. However, whether it inhibits gastric cancer (GC) cell proliferation and migration and the mechanism remain unclear. In the present study, different concentrations of TSN were co-incubated with SGC-7901 cells. The pcDNA-FOXM1 or FOXM1-siRNA plasmid was transfected into cells before treatment with 5 µg/l TSN. The proliferation and migration abilities of the SGC-7901 cells were tested by MTT and wound healing assays. Western blotting was used to investigate the expression levels of P21, Ki-67, PCNA, MMP-2, MMP-9 and FOXM1. We found that compared with the control, the proliferation and migration abilities of the SGC-7901 cells were decreased after incubation with different concentrations of TSN in a dose-dependent manner (p<0.01). Moreover, the expression levels of Ki-67, PCAN, MMP-2, MMP-9 and FOXM1 were decreased, and P21 was increased in the TSN-treated SGC-7901 cells (p<0.01). In addition, downregulation of FOXM1 by FOXM1-siRNA had the same effect as TSN on SGC-7901 cells, and overexpression of FOXM1 partly abrogated TSN-mediated inhibition of SGC-7901 cell proliferation and migration. These results suggested that TSN inhibits SGC-7901 cell proliferation and migration by downregulation of FOXM1.