Evaluation of miR-21 and miR-375 as prognostic biomarkers in oesophageal cancer in high-risk areas in China

Possible Role of miR-375-3p in Cervical Lymph Node Metastasis of Oral Squamous Cell Carcinoma

No clinically useful predictors of latent cervical lymph node metastasis (LNM) in early oral squamous cell carcinoma (OSCC) are available. In this study, we focused on the microRNAs (miRNAs) involved in the expression of numerous genes and explored those associated with latent cervical LNM in early OSCC (eOSCC). First, microarray and RT-PCR analyses revealed a significant downregulation of miR-375-3p expression in primary eOSCC tissues with latent cervical LNM. Next, we examined the effects of miR-375-3p mimics on the growth and migration of four human OSCC cell lines that do not express miR-375-3p. The overexpression of miR-375-3p significantly suppressed the cell proliferation and migration of human OSCC cells in vitro. Furthermore, miR-375-3p mimics markedly inhibited the subcutaneously xenografted human OSCC tumors. Finally, we found the genes involved in the PI3K-AKT pathway and cell migration as target gene candidates of miR-375-3p in human OSCC cells. These findings suggest that miR-375-3p functions as a tumor suppressive-miRNA in OSCC and may serve as a potential biomarker for the prediction of latent cervical LNM in eOSCC and a useful therapeutic target to suppress OSCC progression.

Downregulation of SLC3A2 mediates immune evasion and accelerates metastasis in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a common malignancy originating from oral mucosal tissue. OSCC cells employ immune evasion strategies to avoid immune attacks, but research on inhibiting immune evasion and delaying OSCC progression is limited. This study aimed to investigate how SLC3A2 downregulation mediates immune evasion and promotes metastasis in OSCC through bioinformatics analysis and cell experiments. Gene enrichment analysis was performed using human double sulphur death-related genes from the GSEA database. Differentially expressed genes were selected from the GEO database. Diagnostic models were constructed and validated using gene expression datasets. Immune infiltration and function were analysed through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Cell experiments were conducted to evaluate the impact of SLC3A2 on immune response in OSCC. Ten double sulphur death-related genes were identified, with SLC3A2 and SLC7A11 being enriched in tongue squamous cell carcinoma-related diseases. Differential expression analysis revealed five genes (SLC3A2, SLC7A11, RPN1, GYS1 and NDUFS1) of diagnostic significance. GO analysis showed enrichment in amino acid import and transmembrane transport, while KEGG pathway analysis highlighted enrichment in ferroptosis, diabetic cardiomyopathy, and Starch and sucrose metabolism. Experimental verification confirmed higher SLC3A2 expression in OSCC cells. Overexpression of SLC3A2 inhibited cell proliferation and reduced PD-1 and CTLA-4 expression. Reduced SLC3A2 expression in OSCC promotes immune evasion and tumour progression by impairing T lymphocyte function. This study provides insights into targeted regulation of SLC3A2 expression for immune response-based therapies in OSCC.

Cellular zinc metabolism and zinc signaling: from biological functions to diseases and therapeutic targets

Zinc metabolism at the cellular level is critical for many biological processes in the body. A key observation is the disruption of cellular homeostasis, often coinciding with disease progression. As an essential factor in maintaining cellular equilibrium, cellular zinc has been increasingly spotlighted in the context of disease development. Extensive research suggests zinc's involvement in promoting malignancy and invasion in cancer cells, despite its low tissue concentration. This has led to a growing body of literature investigating zinc's cellular metabolism, particularly the functions of zinc transporters and storage mechanisms during cancer progression. Zinc transportation is under the control of two major transporter families: SLC30 (ZnT) for the excretion of zinc and SLC39 (ZIP) for the zinc intake. Additionally, the storage of this essential element is predominantly mediated by metallothioneins (MTs). This review consolidates knowledge on the critical functions of cellular zinc signaling and underscores potential molecular pathways linking zinc metabolism to disease progression, with a special focus on cancer. We also compile a summary of clinical trials involving zinc ions. Given the main localization of zinc transporters at the cell membrane, the potential for targeted therapies, including small molecules and monoclonal antibodies, offers promising avenues for future exploration.

Cross-sectional observational study: Investigation of zinc concentration in white patients with cancer

OBJECTIVES

Numerous studies describe the role of zinc in the immune system and metabolism. Zinc may influence the pathogenesis and prognosis of cancer. The aim of this study to determine the prevalence of zinc deficiency in patients with cancer. The study's primary objective was to evaluate the frequency of zinc deficiency in White patients with cancer and characterize the clinical factors predisposing individuals to decreased zinc concentration. The study also aimed to estimate the dose of zinc supplementation that would prevent deficiency.

METHODS

Retrospective data for this cross-sectional study were analyzed from 300 consecutive white patients diagnosed with neoplastic disease and admitted to a major oncology hospital for treatment. Zinc plasma concentration, nutritional status, body composition, and medical history of ailments and dysphagia were recorded. Supplementation was introduced in patients with zinc deficiency according to the local protocol. Zinc plasma levels were collected at follow-up visits.

RESULTS

Zinc deficiency was diagnosed in 68% of the patients. Poor nutritional status was significantly associated with zinc deficiency (low body mass index, weight loss, low albumin level). Low lean body mass (P = 0.003) and adipose tissue (P = 0.045) correlated with zinc deficiency. Patients with zinc deficiency reported dysphagia more frequently than those with normal zinc levels (18 versus 8%; P = 0.03). Squamous cell carcinoma was significantly associated with zinc deficiency (P = 0.043). Oral zinc supplementation resulted in reaching laboratory norms for plasma concentration in only 27% of patients with zinc deficiency and was not dependent on lower (10-15 mg) or higher (25-30 mg) dosing (P > 0.05).

CONCLUSIONS

Zinc deficiency is common in cachectic, malnourished patients with cancer. Nutritional guidelines for these patients should include screening for micronutrient deficiencies. Further studies are needed to determine the role, dosage, duration, and form of nutritional supplementation recommended for specific cancer diagnoses.

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.

MiR-423-5p is a novel endogenous control for the quantification of circulating miRNAs in human esophageal squamous cell carcinoma

Circulating miRNA expression is most commonly measured by qRT-PCR, however, the lack of a suitable endogenous control hinders people from evaluating the accurate changes in miRNA expression levels and developing the non-invasive biomarkers. In this study, we aimed to screen the specific, highly stable endogenous control in esophageal squamous cell carcinoma (ESCC) to overcome the obstacle. We selected "housekeeping" miRNAs according to the published database and initially acquired 21 miRNAs. Subsequently, we screened these miRNAs using GSE106817 and TCGA datasets according to specific inclusion criteria and evaluated the suitability of "candidate" miRNAs. Among these miRNAs, the average abundance of miR-423-5p was relatively high in serum. Notably, miR-423-5p expression in serum showed no significant difference between ESCC patients and healthy controls (n = 188, P = 0.29). Moreover, among these miRNAs, miR-423-5p was the most stable miRNA using the NormFinder algorithms. Overall, these results indicate that miR-423-5p, as a novel and optimal endogenous control, could be used to quantify circulating miRNAs in ESCC.

Prognostic value of micro-RNA 375, 133, 143, 145 in esophageal carcinoma: A systematic review and meta-analysis

Many studies have confirmed that micro-RNA (mir) is related to the prognosis of esophageal carcinoma (EC), suggesting the mir could be used to guide the therapeutic strategy of EC. Some of mir molecules are considered as favorable prognostic factors for EC. The purpose of our study is to evaluate the prognostic potential of mir-375, 133, 143, 145 in primary EC, we summarized all the results from available studies, aiming delineating the prognostic role of mir in EC. Relevant studies were identified by searching databases including Medline, Embase, Web of science, Cochrane Library. The studies which explored the prognostic value of mir-375, 133, 143, 145 expressions on survival outcomes in patients with EC were included in this study. The hazard ratios (HR) and their responding 95% confidence interval (CI) were also extracted. A total of 25 studies were collected, including 1260 patients, and the prognostic values of four mirs in EC were analyzed. Survival outcomes including overall survival (OS), progression-free survival (PFS) and disease-free survival (DFS) were used as the primary endpoint to evaluate the prognostic value of mir. The pooled analysis results showed that up-regulation of mir-375 indicated favorable OS (HR=0.50; 95%CI: 0.37-0.69; P<0.001). In addition, the up-regulation of mir-133 (HR=0.40, 95%CI: 0.24-0.65, P<0.001), 143 (HR=0.40, 95%CI: 0.21-0.76, P < 0.001) and 145 (HR=0.55, 95%CI: 0.34-0.90, P<0.001) are also proved as protected factors in EC. Therefore, our study demonstrated that these mirs may have the potential to be used as prognostic biomarkers for EC in clinical practice.

Artesunate Inhibits the Development of Esophageal Cancer by Targeting HK1 to Reduce Glycolysis Levels in Areas With Zinc Deficiency

Esophageal cancer (EC) threatens many lives in China, especially in areas with high incidences of EC. Our previous studies proved that zinc deficiency (ZD) promotes the cell cycle, thus promoting the progression of EC in areas with a high incidence of EC. Artesunate could inhibit the cell cycle, thereby inhibiting the progression of EC. In this study, we first demonstrated the mechanism by which artesunate inhibits EC in vitro and then demonstrated that artesunate could reverse the ZD-promoted progression of EC before EC occurred in vivo. The results showed that artesunate could inhibit the cell cycle, metastasis, and glycolysis of EC cells. Artesunate could target HK1, promote HK1 degradation, and reduce the levels of HIF-1α and PKM2 expression, which are key glycolysis enzymes. The in vivo results showed that ZD could increase the expression of HK1 and increase the incidence of EC. Artesunate reduced the incidence of EC and decreased the level of HK1 expression before EC occurred. Artesunate has an anti-EC effect by inhibiting aerobic glycolysis and has the potential to be a drug that prevents EC in areas with a high risk of EC.

BAG2 mediates coelomocyte apoptosis in Vibrio splendidus challenged sea cucumber Apostichopus japonicus

MicroRNAs (miRNAs) are closely related to the occurrence, development, and immune response of diseases. BCL2-associated athanogene 2 (BAG2) is a member of the BAG family that functions in diverse cellular processes, including cell death, differentiation, and cell division. In this study, we cloned the cDNA full-length of sea cucumber (Apostichopus japonicus) BAG2 (AjBAG2) and confirmed it is an anti-apoptotic protein in vitro and in vivo during Vibrio splendidus infection. Moreover, we identified a perfect complementarity between miR-375 and the 3'-untranslated region (UTR) sequence of AjBAG2. The miR-375 expression decreased the luciferase activity dose-dependently when co-transfected with the AjBAG2 3'-UTR-luciferase reporter containing the miR-375 target site in epithelioma papulosum cyprini (EPC) cells. This inhibition was partially recovered by a miR-375 specific inhibitor. The mRNA and protein levels of AjBAG2 were opposite to that of coelomocytes in challenged sea cucumber when treated with miR-375 mimics or inhibitors. Additionally, miR-375 expression induced coelomocytes apoptosis and blocked the anti-apoptotic activity of AjBAG2. Our data demonstrated that AjBAG2 is an anti-apoptotic protein during V. splendidus infection and this function can be inhibited by miR-375 in sea cucumbers.

MicroRNA-375: potential cancer suppressor and therapeutic drug

MiR-375 is a conserved noncoding RNA that is known to be involved in tumor cell proliferation, migration, and drug resistance. Previous studies have shown that miR-375 affects the epithelial-mesenchymal transition (EMT) of human tumor cells via some key transcription factors, such as Yes-associated protein 1 (YAP1), Specificity protein 1 (SP1) and signaling pathways (Wnt signaling pathway, nuclear factor κB (NF-κB) pathway and transforming growth factor β (TGF-β) signaling pathway) and is vital for the development of cancer. Additionally, recent studies have identified microRNA (miRNA) delivery system carriers for improved in vivo transportation of miR-375 to specific sites. Here, we discussed the role of miR-375 in different types of cancers, as well as molecular mechanisms, and analyzed the potential of miR-375 as a molecular biomarker and therapeutic target to improve the efficiency of clinical diagnosis of cancer.

Long noncoding RNA PVT1 promotes tumour progression via the miR-128/ZEB1 axis and predicts poor prognosis in esophageal cancer

PURPOSE

To confirm the value of PVT1 as a prognostic marker both in tumour tissue and serum of patients with esophageal cancer and clarify the mechanism.

METHODS

This study analyzed data obtained from 76 patients who were surgically treated from January 1, 2015, to December 31, 2016, and received a pathological diagnosis of ESCC. PVT1 levels in tumour tissue and serum were detected by qRT-PCR. Patient data were extracted from medical records, and follow-up evaluations were performed. The roles of PVT1 in proliferation, migration and invasion were by CCK-8 and Transwell in stable knockdown PVT1 cell lines. Signal pathways PVT1 promotes esophageal cancer were detected by qRT-PCR and western blot.

RESULTS

PVT1 was overexpression in esophageal cancer tissues and high levels of PVT1 were correlated with lymphatic metastasis, high TNM stage and postoperative metastasis. High levels of PVT1 in tissues were correlated with worse metastasis-free survival (MFS) (HR: 2.578, 95% CI: 1.369-4.853). High level of PVT1 in serum was correlated with postoperative metastasis. High levels of PVT1 in serum were correlated with worse overall survival (OS) (HR: 2.124, 95% CI: 1.078-4.186) and worse MFS (HR: 2.786, 95% CI: 1.557-4.985). Knockdown of PVT1 decreased the cell proliferation, migration and invasion abilities of esophageal cancer cell lines. The expression of ZEB1 was significantly downregulated, and the expression of E-cadherin was increased by the knockdown of PVT1. Knockdown of miR-128 restored the altered proliferation, migration and invasion and the expression of ZEB1 and E-cadherin caused by knockdown of PVT1.

CONCLUSIONS

High levels of PVT1 in serum were correlated with postoperative metastasis and a poor prognosis. PVT1 promoted ESCC progression via the miR-128/ZEB1/E-cadherin axis.

Correlation of plasma miR-21 and miR-93 with radiotherapy and chemotherapy efficacy and prognosis in patients with esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the main causes of human death. It is usually already in middle or advanced stage when diagnosed due to its hidden symptoms in early stage. Therefore, patients have already lost the best surgical timing when diagnosed. Radiotherapy and chemotherapy are standard treatment methods for ESCC clinically, but the efficacy and prognosis of patients from them are still unsatisfactory. Therefore, it is of great clinical significance to seek for biomarkers that can predict the radiotherapy and chemotherapy response and prognosis of ESCC patients.

AIM

To explore the clinical value of plasma miR-21 and miR-93 in ESCC.

METHODS

A total of 128 ESCC patients admitted to the First Affiliated Hospital of Zhenzhou University were enrolled as a study group and treated with concurrent radiotherapy and chemotherapy, and other 45 healthy people during the same period were enrolled as a control group. The expression of plasma miR-21 and miR-93 was determined using quantitative real-time polymerase chain reaction, and the correlation of expression of plasma miR-21 and miR-93 with clinical pathological parameters about the patients was analyzed. The receiver operating characteristic (ROC) curve was adopted to assess the diagnostic value of plasma miR-21 and miR-93 for clinical pathological features of ESCC patients, the Logistic regression analysis adopted to analyze the risk factors for radiotherapy and chemotherapy efficacy in ESCC patients, and the Cox regression analysis to identify the prognostic factors for ESCC patients.

RESULTS

The study group showed significantly higher relative expression of plasma miR-21 and miR-93 than the control group (P < 0.01). The area under the ROC curve (AUC) of plasma miR-21 for diagnosing T stage, N stage, M stage, and pathological differentiation of ESCC was 0.819, 0.758, 0.824, and 0.725, respectively, and that of plasma miR-93 for diagnosing T stage, N stage, and M stage of ESCC was 0.827, 0.815, and 0.814, respectively. The AUC of combined plasma miR-21 and miR-93 for predicting radiotherapy and chemotherapy efficacy before radiotherapy and chemotherapy was 0.894, and the AUCs of them for predicting the 3-year overall survival (OS) were 0.861 and 0.807, respectively. T stage (P < 0.05), M stage (P < 0.05), miR-21(P < 0.01), and miR-93 (P < 0.05) were independent risk factors for radiotherapy and chemotherapy efficacy, and T stage (P < 0.01), N stage (P < 0.05), M stage (P < 0.01), miR-21 (P < 0.01), and miR-93 (P < 0.01) were independent prognostic factors for ESCC patients.

CONCLUSION

MiR-21 and miR-93 can be adopted as effective biomarkers for predicting radiotherapy and chemotherapy efficacy in ESCC and the 3-year OS of ESCC patients.

Formononetin: A Review of Its Anticancer Potentials and Mechanisms

Cancer, a complex yet common disease, is caused by uncontrolled cell division and abnormal cell growth due to a variety of gene mutations. Seeking effective treatments for cancer is a major research focus, as the incidence of cancer is on the rise and drug resistance to existing anti-cancer drugs is major concern. Natural products have the potential to yield unique molecules and combinations of substances that may be effective against cancer with relatively low toxicity/better side effect profile compared to standard anticancer therapy. Drug discovery work with natural products has demonstrated that natural compounds display a wide range of biological activities correlating to anticancer effects. In this review, we discuss formononetin (C₁₆H₁₂O₄), which originates mainly from red clovers and the Chinese herb Astragalus membranaceus. The compound comes from a class of 7-hydroisoflavones with a substitution of methoxy group at position 4. Formononetin elicits antitumorigenic properties in vitro and in vivo by modulating numerous signaling pathways to induce cell apoptosis (by intrinsic pathway involving Bax, Bcl-2, and caspase-3 proteins) and cell cycle arrest (by regulating mediators like cyclin A, cyclin B1, and cyclin D1), suppress cell proliferation [by signal transducer and activator of transcription (STAT) activation, phosphatidylinositol 3-kinase/protein kinase-B (PI3K/AKT), and mitogen-activated protein kinase (MAPK) signaling pathway], and inhibit cell invasion [by regulating growth factors vascular endothelial growth factor (VEGF) and Fibroblast growth factor 2 (FGF2), and matrix metalloproteinase (MMP)-2 and MMP-9 proteins]. Co-treatment with other chemotherapy drugs such as bortezomib, LY2940002, U0126, sunitinib, epirubicin, doxorubicin, temozolomide, and metformin enhances the anticancer potential of both formononetin and the respective drugs through synergistic effect. Compiling the evidence thus far highlights the potential of formononetin to be a promising candidate for chemoprevention and chemotherapy.

The microRNA-375 as a potentially promising biomarker to predict the prognosis of patients with head and neck or esophageal squamous cell carcinoma: a meta-analysis

BACKGROUND

The prognostic value of microRNA-375 (miR-375) expression in squamous cell carcinoma (SCC) had been reported in the previous studies; however, the results remain inconsistent. This study was performed to investigate the prognostic significance of miR-375 expression in SCC based on all eligible evidences.

METHODS

Relevant studies were identified by searching PubMed, Embace, Medline, Cochrane Library, and China Biology Medicine disk. Survival outcome including overall survival (OS) and other survival outcomes were used as the primary endpoint to evaluate the prognostic outcome of patients with SCC. All statistical analyses were performed in RevMan software version 5.3 and STATA software version 14.1. Furthermore, the quality of included studies was assessed by The Newcastle-Ottawa Scale.

RESULTS

In total, 13 studies, including 1340 patients, met the inclusion criteria for our meta-analysis. The pooled analysis results indicated that downregulation of miR-375 significantly predicted poor OS (HR 1.58, 95% CI 1.34-1.88, P < 0.001). Downregulated miR-375 was also correlated with the other survival outcomes. Subgroup analysis based on tumor type found that lower expression of miR-375 was significantly related with poor OS in patients with esophageal squamous cell carcinoma (ESCC) (HR 1.58, 95% CI 1.29-1.94, P < 0.001) and head and neck squamous cell carcinoma (HNSCC) (HR 1.59, 95% CI 1.16-2.18, P = 0.004).

CONCLUSIONS

This meta-analysis demonstrated that the downexpression of miR-375 was significantly correlated with poor OS in patients with SCCs and indicated the potential clinical use of miR-375 as a molecular biomarker, particularly in assessing prognosis for patients with ESCC and HNSCC.

Development of a miRNA-seq based prognostic signature in lung adenocarcinoma

Background

We utilized miRNAs expression and clinical data to develop a prognostic signature for patients with lung adenocarcinoma, with respect to their overall survival, to identify high-risk subjects based on their miRNA genomic profile.

Methods

MiRNA expressions based on miRNA sequencing and clinical data of lung adenocarcinoma patients (n = 479) from the Cancer Genome Atlas were randomly partitioned into non-overlapping Model (n = 320) and Test (n = 159) sets, respectively, for model estimation and validation.

Results

Among the ten miRNAs identified using the univariate Cox analysis, six from miR-8, miR-181, miR-326, miR-375, miR-99a, and miR-10, families showed improvement of the overall survival chance, while two miRNAs from miR-582 and miR-584 families showed a worsening of survival chances. The final prognostic signature was developed with five miRNAs—miR-375, miR-582-3p, miR-326, miR-181c-5p, and miR-99a-5p—utilizing a stepwise variable selection procedure. Using the KEGG pathway analysis, we found potential evidence supporting their significance in multiple cancer pathways, including non-small cell lung cancer. We defined two risk groups with a score calculated using the Cox regression coefficients. The five-year survival rates for the low-risk group was approximately 48.76% (95% CI = (36.15, 63.93)); however, it was as low as 7.50% (95% CI = (2.34, 24.01)) for the high-risk group. Furthermore, we demonstrated the effect of the genomic profile using the miRNA signature, quantifying survival rates for hypothetical subjects in different pathological stages of cancer.

Conclusions

The proposed prognostic signature can be used as a reliable tool for identifying high-risk subjects regarding survival based on their miRNA genomic profile.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5206-8) contains supplementary material, which is available to authorized users.

Identification of miR-375 as a potential prognostic biomarker for esophageal squamous cell cancer: A bioinformatics analysis based on TCGA and meta-analysis

Accumulating evidence has demonstrated that aberrantly expressed miRNAs in cancer tissues regulated various cellular processes related to carcinogenesis. The present study aimed to identify the differentially expressed miRNAs between esophageal squamous cell cancer (ESCC) and adjacent normal esophageal tissue (ANET). In our present study, we identified 129 differentially expressed miRNAs between ESCC and ANET by analyzing high-throughput miRNA data downloaded from TCGA database. After investigating the prognostic value of the 129 differential expressed miRNAs, eight miRNAs were found to be associated with prognosis of patients with ESCC. The clinical significance and bio-function of miR-375 was further examined. We performed Gene Set Enrichment Analysis (GSEA) to identify the top three gene sets that significantly altered between the patients with miR-375 low expression and high expression. In order to explore the mechanism of the development and progression of ESCC, the role of miR-375 in ESCC and its four candidate target genes was examined. At last, we performed a meta-analysis to verify the prognostic value of miR-375 in ESCC. In conclusion, our findings suggest that miR-375 serves as a promising independent prognostic factor for ESCC and function as a tumor suppressor.

MicroRNA‑21 regulates the biological behavior of esophageal squamous cell carcinoma by targeting RASA1

MicroRNA‑21 (miR‑21) has been revealed to play a crucial role in regulating the biological behavior, including proliferation, migration, invasion and metastasis in certain cancers. However, its role in esophageal squamous cell carcinoma (ESCC) has yet to be elucidated. Based on the data of GSE13937 downloaded from Gene Expression Omnibus (GEO) database, miR‑21 was revealed to be one of the top 20 differentially expressed (DE) miRNAs screened using the Morpheus online tool. RAS p21 protein activator 1 (RASA1) was predicted as the target gene of miR‑21 using the predicting software and was combined with miR‑21 using the luciferase reporter assay. Its relative expression was significantly decreased, however, miR‑21 was increased in the tumor tissues compared to the normal adjacent tissues in patients with ESCC as determined by quantitative polymerase chain reaction (q‑PCR). Furthermore, overexpression of miR‑21 (mimic) could significantly decrease the gene level of RASA1. Conversely, downregulation of miR‑21 (inhibitor) significantly increased the gene level of RASA1, while downregulation of RASA1 (siRASA1) markedly increased the gene expression of miR‑21. Notably, the expression of Snail and vimentin were significantly increased by upregulation of miR‑21 and downregulation of RASA1. Transwell results revealed that miR‑21 and RASA1 regulated proliferation, migration and invasion in ESCC cells. In an in vivo model, miR‑21 inhibitor (antagomir) could inhibit tumor growth. In conclusion, miR‑21 regulated cell proliferation, migration, invasion and tumor growth of ESCC by directly targeting RASA1, which may have been achieved via regulation of Snail and vimentin. Anti‑miR‑21 revealed an antitumor effect. Thus, it may be considered as a possible target for ESCC therapy.

Methylation‑associated silencing of miR‑128 promotes the development of esophageal cancer by targeting COX‑2 in areas with a high incidence of esophageal cancer

Esophageal cancer is one of the most common cancer types in the world, with a widely varying incidence between different regions. Zinc deficiency (ZD) is very common in high‑risk areas for esophageal cancer. Dietary ZD is reported to be associated with esophageal squamous cell carcinoma (ESCC). In the current study, the effects of ZD on tumorigenesis and expression of inflammatory factors were investigated in mice. It was identified that a ZD diet advanced ESCC and increased the expression of cyclooxygenase‑2 (COX‑2) prior to the occurrence of ESCC in mice. ZD significantly enhanced DNA methyltransferase (DNMT) activity and increased the expression of DNMT1 and DNMT3B. Furthermore, the expression of miR‑128 was downregulated by methylation, and COX‑2, a direct target of miR‑128, was upregulated with the reduction in miR‑128. Upregulation of miR‑128 inhibited the cell cycle, proliferation and metastasis, and the expression of COX‑2, cyclin D1 and retinoblastoma protein (Rb). Furthermore, the relative expression level of miR‑128 was negatively associated with COX‑2 in ESCC tissues. Collectively, these findings indicate that methylation‑associated silencing of miR‑128 promotes the development of esophageal cancer through upregulation of the expression of cyclin D1 and Rb by targeting COX‑2 in ZD regions with a high incidence of esophageal cancer.

Prognostic significance of miR-21 and PDCD4 in patients with stage II esophageal carcinoma after surgical resection

Many studies have shown that randomized clinical trial with long-term follow-up found no improvement in stage II esophageal carcinoma (EC) patients receiving preoperative neoadjuvant chemoradiotherapy or chemotherapy treatment, this limitation underscored the urgent need for novel and reliable biomarkers for prognosis and prediction in stage II EC. miR-21 is frequently over-expressed while programmed cell death 4 (PDCD4) is often down-regulated in solid tumors. This study aimed to investigate the clinicopathological and prognostic significance of miR-21 and PDCD4 expression and to elucidate any correlation between miR-21 and PDCD4 expression in stage II EC patients. The expression level of miR-21 was up-regulated while the PDCD4 protein was down-regulated in stage II EC tissues compared with the adjacent non-cancerous tissues. Analyses of the clinicopathological parameters indicated that miR-21 expression was associated with differentiation grade, T stage, and N stage. PDCD4 protein expression was associated with T stage, N stage, and tumor size. The univariate linear regression analysis suggested a significant negative correlation between miR-21 and PDCD4 expression. The Kaplan-Meier curve showed that high miR-21 expression or low PDCD4 expression predicted poor progression-free survival (PFS) and overall survival (OS) of patients with stag II EC. In conclusion, both up-regulated miR-21 and down-regulated PDCD4 expression were associated with the aggressive progression and poor prognosis of stage II EC. miR-21 and PDCD4 might be potential biomarkers of tumor progression and indicators of prognosis of stag II EC.

MiR-375: A prospective regulator in medullary thyroid cancer based on microarray data and bioinformatics analyses

BACKGROUND

This research aims to investigate the prospective molecular mechanism of miR-375 in Medullary Thyroid Cancer (MTC).

MATERIAL AND METHODS

The expression level of miR-375 in MTC was explored with microarray data from Gene Expression Omnibus (GEO). To gather the putative target genes of miR-375, we selected eligible datasets in GEO, in which antagomir-375 and premir-375 were transfected to provide the miR-375-related genes. Subsequently, we attained the intersection of the results of GEO microarray data and 12 online target genes prediction database as the prospective target genes. Furthermore, we conducted in silico analysis including gene ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways annotations and Protein-Protein Interactions (PPI) analysis to provide an overview of the function of miR-375 in MTC. Finally, data from The Cancer Genome Atlas (TCGA) and The Human Protein Atlas (THPA) were used for a validation.

RESULTS

Up-regulation could be confirmed with the data from GSE40807. GEO dataset GSE67742 provided 10,596 miR-375-related genes, while 12 online prediction databases showed that 3352 target genes appeared no less than four times. Finally, the intersection of the two groups of genes included 1132 prospective targets. In aspect of functional annotation, negative regulation of transcription from RNA polymerase II promoter (P=9.83E-06), golgi membrane (P=9.98E-05) and pathway of protein binding (P=3.63E-07) were highlighted as the most enriched terms with GO analysis. With regards to PPI network, 162 hub genes that interacted with no less than 10 other different genes was visualized, among which PI3K/Akt signaling pathway was the most enriched pathway as assessed by KEGG. Furthermore, two genes (JAK2 and NGFR) in PI3K/Akt signaling pathway showed down-regulated patterns in both mRNA and protein levels.

CONCLUSION

The higher expression level of miR-375 might play a pivotal role in the tumorigenesis of MTC via targeting multiple key pathways, especially PI3K/Akt pathway. However, the exact molecular mechanism of miR-375 needs to be verified with in-depth investigation in the future.

Research progress on the relationship between zinc deficiency, related microRNAs, and esophageal carcinoma

Esophageal cancer (EC) is a common malignant tumor of the gastrointestinal tract with a high incidence in China. Zinc (Zn) deficiency is a key risk factor for the occurrence and development of EC and affects progression by regulating microRNA (miRNA, miR) expression. In addition, the dysregulation of miRNAs is accompanied by the dysregulation of their target genes in EC. In this paper, we review the potential molecular mechanisms between Zn deficiency and EC with the aim of providing new strategies and methods for early diagnosis, targeted therapy, and prognostic evaluation.

Analysis of the function of microRNA-375 in humans using bioinformatics

MicroRNA-375 (miR-375) is expressed at low levels in many types of solid tumor, particularly in gastrointestinal tumors. It is considered to be important in the development of cancer and certain diseases. Thus, more detailed knowledge is required on the particular functions of miR-375. miRs function by regulating target genes. Therefore, in the current study, miRWalk (which includes the data from 10 prediction software programs) was used to predict the target genes of miR-375. The genes, which were co-predicted using five different software programs were further analyzed using Database for Annotation, Visualization and Integrated Discovery online software [including gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis]. Subsequently, the online tool, Search Tool for the Retrieval of Interacting Genes, was used to analyze the protein-protein interaction and construct modules using Cytoscape. The result demonstrated 6,574 predicted genes, 1,325 of which were co-predicted. The GO analysis result indicated that, in biological processes, the co-predicted genes were significantly enriched in the regulation of nervous system development and cell differentiation, and the highest enrichment of molecular function was ion binding. In KEGG analysis, the genes were enriched in the Hippo signaling pathway, glutamatergic synapse, circadian entrainment and the phosphoinositide 3-kinase (PI3K)-Akt signaling pathway. The top 10 hub proteins were mechanistic target of rapamycin, PH domain and leucine rich repeat protein phosphatase 1, ubiquitously transcribed tetratricopeptide repeat containing, Y-linked, histone deacetylase 2, F-box and leucine rich repeat protein 19, KIT proto-oncogene receptor tyrosine kinase, angiotensinogen, Janus kinase 2, fibroblast growth factor 2 and RNA polymerase II subunit A. These proteins predominantly regulate the development and progression of cancer, hypertension, essential thrombocythemia and inflammation. The genes in the top seven modules selected were identified to be primarily enriched in chemokines, extracellular matrix-receptor interaction, focal adhesion, the PI3K-Akt signaling pathway, amoebiasis and protein processing signaling pathway. Thus, the target genes and hub proteins that were predicted in the current study were identified to be important in regulating the development and progression of cancer and certain diseases. Furthermore, they present potential novel biomarkers for tumor diagnosis and candidate targets for treatment, and indicate that further research is required to establish the functions of miR-375.