miR-25 promotes metastasis via targeting FBXW7 in esophageal squamous cell carcinoma

Role of Non-coding RNAs in the Response of Glioblastoma to Temozolomide

Chemotherapy and radiotherapy are widely used in clinical practice across the globe as cancer treatments. Intrinsic or acquired chemoresistance poses a significant problem for medical practitioners and researchers, causing tumor recurrence and metastasis. The most dangerous kind of malignant brain tumor is called glioblastoma multiforme (GBM) that often recurs following surgery. The most often used medication for treating GBM is temozolomide chemotherapy; however, most patients eventually become resistant. Researchers are studying preclinical models that accurately reflect human disease and can be used to speed up drug development to overcome chemoresistance in GBM. Non-coding RNAs (ncRNAs) have been shown to be substantial in regulating tumor development and facilitating treatment resistance in several cancers, such as GBM. In this work, we mentioned the mechanisms of how different ncRNAs (microRNAs, long non-coding RNAs, circular RNAs) can regulate temozolomide chemosensitivity in GBM. We also address the role of these ncRNAs encapsulated inside secreted exosomes.

FBXW7 affects autophagy through MCL1 in oral squamous cell carcinoma

BACKGROUND

Oral cancer is associated with high risk of morbidity and mortality. However, effective treatment for oral cancer is urgently required in clinics. In this study, we aimed to determine whether F-box/WD repeat-containing protein 7 (FBXW7), an essential tumor suppressor gene, can regulate autophagy and improve the prognosis in oral squamous cell carcinoma (OSCC).

METHODS

mRNA levels of FBXW7 and myeloid cell leukemia 1 (MCL-1) in OSCC tissues and adjacent normal tissues were measured by qRT-PCR. FBXW7 and MCL-1 were overexpressed in OSCC cell line using lentivirus containing FBXW7 and MCL-1, respectively. Protein expression was determined by Western blot.

RESULTS

The mRNA and protein levels of FBXW7 were decreased in patients with OSCC, whereas the mRNA and protein levels of MCL-1 were increased. Moreover, the mRNA coding for autophagy proteins was reduced in patients with OSCC. Additionally, it was found that overexpression of FBXW7 significantly reduced MCL-1 expression and upregulated autophagy-related proteins, including Beclin1, autophagy related 7, and microtubule-associated protein light chain 3.

CONCLUSION

Our results suggest that FBXW7 affects autophagy through MCL1 in OSCC.

Mir-25 Promotes Metastasis of Esophageal Cancer by Targeting BTG2

At present times, various kinds of literature have suggested the miR-25 acts as an oncogene in various types of human malignancies and until now, very less work has been performed pertaining to the role of miR-25 in esopharyngeal cancer. This study was performed to confirm that miR-25 is overexpressed in esophageal squamous cell carcinoma (ESCC) tumor tissue as a prognostic biomarker and to clarify the mechanism of miR-25. The expression levels of miR-25 and BTG2 were detected in esophageal squamous cell carcinoma tumor tissue. A stably knocked-down miR-25 cell line (miR-25KD) was established in esophageal squamous cell carcinoma cell lines. Moreover, a CCK-8 assay was performed for determining the role of miR-25 in proliferation. The Transwell assays were organized to detect metastasis. Later, a gene profiling study was carried out to identify the gene expression pertaining to tumor progression. The expression of miR-25 in the esophageal cancer tissues was much higher compared with that in paracarcinoma tissues (6.42±4.28 VS 3.36±2.63, p<0.001). A high level of miR-25 was identified to be correlated with postoperative metastasis (χ2=8.187, p =0.004). BTG2 levels were significantly lower in tumor tissues (3.24±2.79) than those in adjacent non-tumor tissues (1.96±1.56 VS 2.64±1.41, p<0.001). Negative signs of BTG2 were also associated with postoperative metastasis (χ2=7.766, p=0.005). Besides, BTG2-negative cancer tissues are often accompanied by increased miR-25 expression levels (χ2=18.379, p<0.001). Patients with high miR-25 levels were found with worse overall survival (OS) (χ2=6.906, p=0.009) and metastasis-free survival (MFS) (χ2=4.991, p=0.025). Patients with positive BTG2 had better OS (χ2=12.917, p <0.001) and MFS (χ2=14.173, p<0.001). Knockdown of miR-25 helped to inhibit the proliferation and metastatic ability of esophageal cancer cells. Also, MiR-25 inhibits the expression of BTG2 directly. Results also show that miR-25 also helps to suppress the expression of vimentin and increase the expressions of E-cadherin and BTG2. MiR-25 promotes ESCC progression by directly inhibiting the expression of BTG2. MiR-25 and BTG2 can be utilized as prognostic biomarkers.

FBXW7 loss of function promotes esophageal squamous cell carcinoma progression via elevating MAP4 and ERK phosphorylation

BACKGROUND

Increasing evidence suggests that FBXW7 has a high frequency of mutations in esophageal squamous cell carcinoma (ESCC). However, the function of FBXW7, especially the mutations, is not clear. This study was designed to investigate the functional significance of FBXW7 loss of function and underlying mechanism in ESCC.

METHODS

Immunofluorescence was applied to clarify the localization and main isoform of FBXW7 in ESCC cells. Sanger sequencing were performed to explore mutations of FBXW7 in ESCC tissues. Proliferation, colony, invasion and migration assays were performed to examine the functional roles of FBXW7 in ESCC cells in vitro and in vivo. Real-time RT-PCR, immunoblotting, GST-pulldown, LC-MS/MS and co-immunoprecipitation assay were used to explore the molecular mechanism underlying the actions of FBXW7 functional inactivation in ESCC cells. Immunohistochemical staining were used to explore the expression of FBXW7 and MAP4 in ESCC tissues.

RESULTS

The main FBXW7 isoform in ESCC cells was the β transcript in the cytoplasm. Functional inactivation of FBXW7 led to activation of the MAPK signaling pathway and upregulation of the downstream MMP3 and VEGFA, which enhanced tumor proliferation cell invasion and migration. Among the five mutation forms screened, S327X (X means truncated mutation) had an effect similar to the FBXW7 deficiency and led to the inactivation of FBXW7 in ESCC cells. Three other point mutations, S382F, D400N and R425C, attenuated but did not eliminate FBXW7 function. The other truncating mutation, S598X, which was located outside of the WD40 domain, revealed a tiny attenuation of FBXW7 in ESCC cells. Notably, MAP4 was identified as a potential target of FBXW7. The threonine T521 of MAP4, which was phosphorylated by CHEK1, played a key role in the FBXW7-related degradation system. Immunohistochemical staining indicated that FBXW7 loss of function was associated with tumor stage and shorter survival of patients with ESCC. Univariate and multivariate Cox proportional hazards regression analyses showed that high FBXW7 and low MAP4 was an independent prognostic indicator and prospective longer survival. Moreover, a combination regimen that included MK-8353 to inhibit the phosphorylation of ERK and bevacizumab to inhibit VEGFA produced potent inhibitory effects on the growth of FBXW7 inactivation xenograft tumors in vivo.

CONCLUSIONS

This study provided evidence that FBXW7 loss of function promoted ESCC via MAP4 overexpression and ERK phosphorylation, and this novel FBXW7/MAP4/ERK axis may be an efficient target for ESCC treatment.

Deciphering the CircRNA-Regulated Response of Western Honey Bee (Apis mellifera) Workers to Microsporidian Invasion

Vairimorpha ceranae is a widespread fungal parasite of adult honey bees that leads to a serious disease called nosemosis. Circular RNAs (circRNAs) are newly discovered non-coding RNAs (ncRNAs) that regulate biological processes such as immune defense and development. Here, 8199 and 8711 circRNAs were predicted from the midguts of Apis mellifera ligustica workers at 7 d (Am7T) and 10 d (Am10T) after inoculation (dpi) with V. ceranae spores. In combination with transcriptome data from corresponding uninoculated midguts (Am7CK and Am10CK), 4464 circRNAs were found to be shared by these four groups. Additionally, 16 circRNAs were highly conserved among A. m. ligustica, Apis cerana cerana, and Homo sapiens. In the Am7CK vs. Am7T (Am10CK vs. Am10T) comparison group, 168 (306) differentially expressed circRNAs (DEcircRNAs) were identified. RT-qPCR results showed that the expression trend of eight DEcircRNAs was consistent with that in the transcriptome datasets. The source genes of DEcircRNAs in Am7CK vs. Am7T (Am10CK vs. Am10T) were engaged in 27 (35) GO functional terms, including 1 (1) immunity-associated terms. Moreover, the aforementioned source genes were involved in three cellular immune-related pathways. Moreover, 86 (178) DEcircRNAs in workers' midguts at 7 (10) dpi could interact with 75 (103) miRNAs, further targeting 215 (305) mRNAs. These targets were associated with cellular renewal, cellular structure, carbohydrate and energy metabolism, and cellular and humoral immunity. Findings in the present study unraveled the mechanism underlying circRNA-mediated immune responses of western honey bee workers to V. ceranae invasion, but also provided new insights into host-microsporidian interaction during nosemosis.

Implications of FBXW7 in Neurodevelopment and Neurodegeneration: Molecular Mechanisms and Therapeutic Potential

The ubiquitin-proteasome system (UPS) mediated protein degradation is crucial to maintain quantitive and functional homeostasis of diverse proteins. Balanced cellular protein homeostasis controlled by UPS is fundamental to normal neurological functions while impairment of UPS can also lead to some neurodevelopmental and neurodegenerative disorders. Functioning as the substrate recognition component of the SCF-type E3 ubiquitin ligase, FBXW7 is essential to multiple aspects of cellular processes via targeting a wide range of substrates for proteasome-mediated degradation. Accumulated evidence shows that FBXW7 is fundamental to neurological functions and especially implicated in neurodevelopment and the nosogenesis of neurodegeneration. In this review, we describe general features of FBXW7 gene and proteins, and mainly present recent findings that highlight the vital roles and molecular mechanisms of FBXW7 in neurodevelopment such as neurogenesis, myelination and cerebral vasculogenesis and in the pathogenesis of some typical neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease and Huntington’s disease. Additionally, we also provide a prospect on focusing FBXW7 as a potential therapeutic target to rescue neurodevelopmental and neurodegenerative impairment.

Exosomal transfer of miR‑25‑3p promotes the proliferation and temozolomide resistance of glioblastoma cells by targeting FBXW7

Intrinsic or acquired resistance to temozolomide (TMZ) is a frequent occurrence in patients with glioblastoma (GBM). Accumulating evidence has indicated that the exosomal transfer of proteins and RNAs may confer TMZ resistance to recipient cells; however, the potential molecular mechanisms are not fully understood. Thus, the aim of the present study was to elucidate the possible role of exosomal microRNAs (miRNAs/miRs) in the acquired resistance to TMZ in GBM. A TMZ-resistant GBM cell line (A172R) was used, and exosomes derived from A172R cells were extracted. Exosomal miR-25-3p was identified as a miRNA associated with TMZ resistance. The potential functions of exosomal miR-25-3p were evaluated by reverse transcription-quantitative PCR, as well as cell viability, colony formation and soft agar assay, flow cytometry, western blot analysis, BrdU incorporation assay, tumor xenograft formation, luciferase reporter assay and RNA immunoprecipitation. It was found that A172R-derived exosomes promoted the proliferation and TMZ resistance of sensitive GBM cells. Moreover, miR-25-3p epxression was upregulated in the exosomes of A172R cells and in serum samples of patients with GBM treated with TMZ. The depletion of exosomal miR-25-3p partially abrogated the effects induced by the transfer of exosomes from A172R cells. By contrast, miR-25-3p overexpression facilitated the proliferation and TMZ resistance of sensitive GBM cells. F-box and WD repeat domain-containing-7 (FBXW7) was identified as a direct target of miR-25-3p. FBXW7 knockdown promoted the proliferation and TMZ resistance of GBM cells. Furthermore, the exosomal transfer of miR-25-3p promoted c-Myc and cyclin E expression by downregulating FBXW7. Our results provided a novel insight into exosomal microRNAs in acquired TMZ resistance of GBM cells. Besides, exosomal miR-25-3p might be a potential prognostic marker for GBM patients.

Construction of a Nine-MicroRNA-Based Signature to Predict the Overall Survival of Esophageal Cancer Patients

BACKGROUND

Esophageal cancer (EC) is a common malignant tumor. MicroRNAs (miRNAs) play a key role in the occurrence and metastasis and are closely related to the prognosis of EC. Therefore, it will provide a powerful tool to predict the overall survival (OS) of EC patients based on miRNAs expression in EC tissues and blood samples.

METHODS

Five independent databases, TCGA, GSE106817, GSE113486, GSE122497, and GSE112264, were used to construct nine-miRna signature and nomograms for prognosis. The bioinformatics analysis was used to predict the enrichment pathways of targets.

RESULTS

A total of 132 overexpressed miRNAs and 23 suppressed miRNAs showed significant differential expression in both EC serum and tissue samples compared with normal samples. We also showed that nine miRNAs were related to the prognosis of EC. Higher levels of miR-15a-5p, miR-92a-3p, miR-92a-1-5p, miR-590-5p, miR-324-5p, miR-25-3p, miR-181b-5p, miR-421, and miR-93-5p were correlated to the shorter survival time in patients with EC. In addition, we constructed a risk prediction model based on the levels of nine differentially expressed miRNAs (DEMs) and found that the OS time of EC patients with high-risk score was shorter than that of EC patients with low-risk score. Furthermore, our results showed that the risk prediction scores of EC samples were higher than those of normal samples. Finally, the area under the curve (AUC) was used to analyze the risk characteristics of EC and normal controls. By calculating the AUC and the calibration curve, the RNA signature showed a good performance. Bioinformatics analysis showed that nine DEMs were associated with several crucial signaling, including p53, FoxO, PI3K-Akt, HIF-1, and TORC1 signaling. Finally, 14 messenger RNAs (mRNAs) were identified as hub targets of nine miRNAs, including BTRC, SIAH1, RNF138, CDC27, NEDD4L, MKRN1, RLIM, FBXO11, RNF34, MYLIP, FBXW7, RNF4, UBE3C, and RNF111. TCGA dataset validation showed that these hub targets were significantly differently expressed in EC tissues compared with normal samples.

CONCLUSION

We have constructed maps and nomograms of nine-miRna risk signals associated with EC prognosis. Bioinformatics analysis revealed that nine DEMs were associated with several crucial signaling, including p53, FoxO, PI3K-Akt, HIF-1, and TORC1 signaling, in EC. We think that this study will provide clinicians with an effective decision-making tool.

Clinical significance of miR-1298 in cervical cancer and its biological function in vitro

Cervical cancer is one of the most malignant tumors in women. miR-1298 was reported to be abnormally expressed and serve crucial role in tumorigenesis of several types of cancer; however, the role of miR-1298 in cervical cancer remains unknown. The present study aimed to evaluate the clinical and biological significance of miR-1298 in cervical cancer. To do so, the expression level of miR-1298 in cervical cancer tissues and cells was evaluated by reverse transcription quantitative PCR. Kaplan-Meier survival analysis and Cox regression analysis were used to explore the prognostic significance of miR-1298 in patients with cervical cancer. Cell Counting Kit-8 and Transwell migration and invasion assays were used to evaluate the effect of miR-1298 on the proliferative, migratory and invasive abilities of cervical cancer cells, respectively. The expression of miR-1298 was lower in cancer tissues and cells compared with normal tissues and cells. Furthermore, miR-1298 expression was associated with lymph node metastasis, tumor diameter and staging from the International Federation of Gynecology and Obstetrics. In addition, patients with low miR-1298 expression had poorer overall survival. These findings suggested that miR-1298 may be considered as an independent prognostic factor for patients with cervical cancer. Furthermore, the results demonstrated that miR-1298 knockdown could promote tumor cell proliferation and migratory and invasive abilities. In addition, nucleus accumbens-associated 1 (NACC1) was demonstrated to be a direct target of miR-1298. Taken together, these findings indicated that miR-1298 overexpression may be considered as a prognostic biomarker for cervical cancer and that miR-1298 may play an inhibitor role in cervical cancer by targeting NACC1.

MicroRNA-25 Exerts an Oncogenic Function by Regulating the Ubiquitin Ligase Fbxw7 in Hepatocellular Carcinoma

BACKGROUND

MicroRNA (miRNA) expression abnormalities are implicated in tumor progression. Previous reports have indicated that microRNA-25 (miR-25) acts as a tumor suppressor or oncogene in diverse cancers. However, its molecular mechanisms in hepatocellular carcinoma (HCC) are still unclear. F-box and WD repeat domain 7 (Fbxw7) is a critical tumor suppressor and is one of the most important deregulated proteins of the ubiquitin-proteasome system in cancer. Our objective was to elucidate the role of miR-25 and Fbxw7 in HCC and to clarify the mechanism by which Fbxw7 is regulated.

METHODS

Fbxw7 expression was estimated in 210 fixed paraffin-embedded HCC samples by immunohistochemistry, and miR-25 expression was evaluated in 142 frozen HCC tissue samples by quantitative real-time PCR. Oncogenic functions of miR-25 and its role in the regulation of Fbxw7 expression were assayed in vitro.

RESULTS

miR-25 was overexpressed in HCC tissue compared with adjacent normal tissue and significantly correlated with a poorer prognosis. Moreover, it was inversely correlated with Fbxw7 expression in HCC tissues. Furthermore, miR-25 inhibition significantly reduced the proliferation, migration, and invasion of HCC cells in vitro.

CONCLUSION

miR-25 may promote tumor progression in HCC patients by repression of Fbxw7 and could serve as a promising molecular target for HCC treatment.

Identification of miR‑25‑3p as a tumor biomarker: Regulation of cellular functions via TOB1 in breast cancer

Breast cancer is the most common cancer in women and is one of the three most common malignancies worldwide. Serum microRNAs (miRNAs/miRs) are ideal biomarkers for tumor diagnosis and prognosis due to their specific biological characteristics. In several different types of cancer, miRNAs are associated with cell migration and invasion. In the present study, miR‑25‑3p expression levels were detected in tissue and serum samples derived from patients with breast cancer, and the diagnostic and prognostic value of miR‑25‑3p in breast cancer was evaluated. Cellular function assays were performed to evaluate the role of miR‑25‑3p in breast cancer. Moreover, dual‑luciferase reporter assays and western blotting were performed to investigate the target of miR‑25‑3p. miR‑25‑3p expression was upregulated in breast cancer tissue and serum samples compared with normal breast tissue and serum samples. Patients with breast cancer with high serum miR‑25‑3p levels were more likely to have lymph node metastasis compared with those with low serum miR‑25‑3p levels. The area under the curve for miR‑25‑3p in the diagnosis of breast cancer was 0.748, with 57.1% sensitivity and 95.0% specificity. Moreover, the Kaplan‑Meier survival curves demonstrated that patients with breast cancer with a low expression of serum miR‑25‑3p had a higher overall survival rate compared with patients with a high serum miR‑25‑3p expression. miR‑25‑3p knockdown suppressed breast cancer cell proliferation and invasion, and transducer of ERBB2, 1 (TOB1) was identified as a potential target gene regulated by miR‑25‑3p. Therefore, the present study suggested that miR‑25‑3p regulated cellular functions via TOB1 in breast cancer; therefore, miR‑25‑3p may serve as a breast cancer biomarker.

Silencing of methyltransferase-like 3 inhibits oesophageal squamous cell carcinoma

Methyltransferase-like 3 (METTL3) is a methyltransferase responsible for N6-methyladenosine mRNA modifications, which has been demonstrated to serve oncogenic roles in various types of cancer; however, the exact function of METTL3 in oesophageal squamous cell carcinoma (ESCC) has not been determined. The present study aimed to explore the regulatory role of METTL3 in ESCC. In the present study, reverse transcription-quantitative PCR and western blotting were used to examine mRNA and protein expression, CCK-8 assays and flow cytometry were used to determine cellular viability and apoptosis, and wound healing and Transwell assays were conducted to study cellular migration and invasion. The expression levels of METTL3 were significantly higher in ESCC tissues and cell lines compared with adjacent non-tumour tissues and the normal oesophageal epithelial cell line HET-1A, respectively. Increased METTL3 expression was associated with an advanced clinical stage of ESCC and poorer prognosis. Furthermore, the genetic knockdown of METTL3 using small interfering RNA significantly suppressed ESCC growth, invasion and migration in vitro, and induced cellular apoptosis, in addition to reducing the phosphorylation levels of PI3K and AKT. In conclusion, the present study demonstrated that the upregulation of METTL3 promoted ESCC progression, and that inhibition of METTL3 significantly suppressed the malignant phenotypes of ESCC cells, at least in part, by downregulating PI3K/AKT signalling activity. Thus, it is suggested that METTL3 may be a promising therapeutic target for ESCC.

Upregulation of cervical carcinoma expressed PCNA regulatory long non-coding RNA promotes esophageal squamous cell carcinoma progression

Cervical carcinoma expressed PCNA regulatory long non-coding (lnc)RNA (CCEPR) has recently been reported to play oncogenic roles in some common types of human cancer. However, the clinical significance of CCEPR mRNA expression levels in esophageal squamous cell carcinoma (ESCC) and the exact function of CCEPR in regulating the malignant phenotypes of ESCC cells have not been previously investigated. In the present study, CCEPR mRNA expression level was upregulated in ESCC tissues and cell lines, and overexpression of CCEPR was associated with advanced TNM stage, lymph node metastasis, and poor prognosis in ESCC. In vitro experiments showed that silencing CCEPR mRNA expression levels significantly suppressed the proliferation, migration, and invasion of ESCC cells, while inducing ESCC cell apoptosis. Furthermore, inhibition of CCEPR decreased the protein expression levels of matrix metalloproteinase (MMP)2 and MMP9 and inhibited epithelial-mesenchymal transition in ESCC cells. In conclusion, the results showed that CCEPR plays an oncogenic role in ESCC and suggests that CCEPR could be used as a potential therapeutic target for ESCC treatment.

Recent insight into the role of FBXW7 as a tumor suppressor

FBXW7 (also known as Fbw7, Sel10, hCDC4, or hAgo) is a tumor suppressor and the most frequently mutated member of the F-box protein family in human cancers. FBXW7 functions as the substrate recognition component of an SCF-type E3 ubiquitin ligase. It specifically controls the proteasome-mediated degradation of many oncoproteins such as c-MYC, NOTCH, KLF5, cyclin E, c-JUN, and MCL1. In this review, we summarize the molecular and biological features of FBXW7 and its substrates as well as the impact of mutations of FBXW7 on cancer development. We also address the clinical potential of anticancer therapy targeting FBXW7.

MicroRNA-1298 is downregulated in non-small cell lung cancer and suppresses tumor progression in tumor cells

BACKGROUND

MicroRNAs (miRNAs) have been reported to serve pivotal roles in tumorigenesis. This study sough to assess the expression and clinical significance of microRNA-1298 (miR-1298) in patients with non-small cell lung cancer (NSCLC), and explore the functional role of miR-1298 in tumorigenesis.

METHODS

One hundred and twenty-one NSCLC patients were recruited in this study. The expression of miR-1298 was estimated using quantitative real-time PCR. Kaplan-Meier survival curves and Cox regression analysis were used to evaluate the prognostic value of miR-1298. Gain- and loss-of-function experiments were preformed to explore the biological function of miR-1298 in NSCLC cells.

RESULTS

Expression levels of miR-1298 were downregulated in NSCLC tissues and cells compared with the corresponding normal controls. The decreased expression of miR-1298 was associated with patients' lymph node metastasis and TNM stage. The low expression of miR-1298 predicted poor overall survival and served as an independent prognostic indicator in NSCLC patients. According to the cell experiments, NSCLC cell proliferation, migration and invasion were inhibited by the overexpression of miR-1298.

CONCLUSION

All the data indicated that the downregulation of miR-1298 predicts poor prognosis of NSCLC, and the overexpression of miR-1298 in NSCLC cells leads to inhibited tumorigenesis. The aberrant miR-1298 may serve as a novel biomarker and therapeutic target in NSCLC.

miR-25-3p promotes glioma cell proliferation and migration by targeting FBXW7 and DKK3

MicroRNAs (miRs) serve important roles in glioma. However, the underlying molecular mechanism of miR-25 in glioma progression remains largely unknown; therefore, it was investigated in the present study. RT-qPCR analysis revealed that miR-25 expression levels were markedly increased in human glioma tissue and glioma cell lines compared with normal brain tissues and normal human astrocytes, respectively. miR-25 upregulation exhibited an association with glioma progression, and the knockdown of miR-25 significantly inhibited glioma cell proliferation and migration. F-box and WD repeat domain containing 7 (FBXW7) and dickkopf WNT signaling pathway inhibitor 3 (DKK3) were identified as target genes of miR-25. FBXW7 and DKK3 expression levels were significantly downregulated in glioma tissue samples compared with normal brain tissue, and their expression levels were negatively regulated by miR-25 expression in glioma cells. Furthermore, inhibition of FBXW7 and DKK3 expression suppressed the miR-25-induced effects on glioma cell proliferation and migration. The findings of the present study suggest that miR-25 may promote glioma cell proliferation and migration by inhibiting the expression of FBXW7 and DKK3. Therefore, miR-25 may serve as a promising molecular target for the treatment of glioma.

F-box/WD-40 repeat-containing protein 7: A potential target in the progression and treatment of gastrointestinal malignancy

Cancer is a principal cause of human morbidity and mortality, with gastrointestinal malignancies, in particular, resulting in a marked number of tumor-associated mortalities. The progression of gastrointestinal malignancy is regulated by a variety of aberrantly expressed proteins, a number of which facilitate tumor progression, whereas, others function as tumor suppressors. The detection of such proteins not only contributes to the early diagnosis of cancer, they may additionally serve as potential therapeutic targets. In normal tissues, numerous proteins encoded by proto-oncoproteins are degraded by ubiquitylation enzymes, consisting of F-box/WD-40 repeat-containing protein 7 (Fbw7) and other proteins, thus avoiding tumorigenesis and maintaining homeostasis. In tumor tissues, the downregulation of Fbw7, caused by various factors, leads to disorders in ubiquitinase synthesis, which may induce tumor progression and chemoresistance, particularly in gastrointestinal malignancy. Therefore, an in-depth study of the regulatory mechanisms involved in disorders of Fbw7 expression and the role of Fbw7 in chemoresistance of gastrointestinal tumors may suggest improvements for early diagnostic screening and targeted therapy.

Prognostic Value of MicroRNAs in Esophageal Carcinoma: A Meta-Analysis

Background

Numerous articles have reported that abnormal expression levels of microRNAs (miRNAs) are related to the survival times of esophageal carcinoma (EC) patients, which contains esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC). Nevertheless, there has not been a comprehensive meta-analysis to assess the accurate prognostic value of miRNAs in EC.

Methods

Studies published in English up to April 12, 2018 that evaluated the correlation of the expression levels of miRNAs with overall survival (OS) in EC were identified by online searches in PubMed, EMBASE, Web of Science, and the Cochrane Database of Systematic Reviews performed by two independent authors. The pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were used to estimate the correlation between OS and miRNA expression. HR ≥ 2 was considered cutoff for considering the miRNA as prognostic candidate.

Results

Forty-four pertinent articles with 22 miRNAs and 4310 EC patients were ultimately included. EC patients with tissue expression levels of high miR-21 or low miR-133a (HR = 2.48, 95% CI = 1.50–4.12), miR-133b (HR = 2.15, 95% CI = 1.27–3.62), miR-138 (HR = 2.27, 95% CI = 1.68–3.08), miR-203 (HR = 2.83, 95% CI = 1.35–5.95), miR-375 and miR-655 (HR = 2.66, 95% CI = 1.16–6.12) had significantly poorer OS (P < 0.05). In addition, EC patients with blood expression levels of high miR-21 (HR = 2.19, 95% CI = 1.31–3.68) and miR-223 had significantly shorter OS (P < 0.05).

Conclusions

In conclusion, tissue expression levels of miR-21, miR-133a, miR-133b, miR-138, miR-203, miR-375, and miR-655 and blood expression levels of miR-21 and miR-223 demonstrate significant prognostic value. Among them, the expression levels of miR-133a, miR-133b, miR-138, miR-203, and miR-655 in tissue and the expression level of miR-21 in blood are potential prognostic candidates for predicting OS in EC.