MicroRNA-98 and microRNA-214 post-transcriptionally regulate enhancer of zeste homolog 2 and inhibit migration and invasion in human esophageal squamous cell carcinoma

Treating human cancer by targeting EZH2

Enhancer of zeste homolog 2 (EZH2), an epigenetic regulator that primarily inhibits downstream gene expression by tri-methylating histone H3, which is usually overexpressed in tumors and participates in many processes such as tumor occurrence and development, invasion, migration, drug resistance, and anti-tumor immunity as an oncogene, making it an important biomarker in cancer therapy. Collectively, several transcription factors and RNAs cooperate to facilitate the elevated expression of EZH2 in cancer. Although the significance of blocking EZH2 in cancer for inhibiting cancer progression is widely recognized, the clinical application of EZH2 inhibitors continues to encounter numerous challenges. In this review, drawing upon our comprehensive understanding of the factual underpinnings of EZH2's role in cancer, we aim to clarify the crucial importance of targeting EZH2 in cancer treatment. Furthermore, we summarize the current research landscape surrounding targeted EZH2 inhibitors and offer insights into potential future applications of these inhibitors.

MicroRNA-98 as a novel diagnostic marker and therapeutic target in cancer patients

The progress of cancer treatment methods in the last decade has significantly reduced mortality rate among these patients. Nevertheless, cancer is still recognized as one of the main causes of human deaths. One of the main reasons for the high death rate in cancer patients is the late diagnosis in the advanced tumor stages. Therefore, it is necessary to investigate the molecular biology of tumor progressions in order to introduce early diagnostic markers. MicroRNAs (miRNAs) have an important role in regulating cellular processes associated with tumor progression. Due to the high stability of miRNAs in body fluids, they are widely used as non-invasive markers in the early tumor diagnosis. Since, deregulation of miR-98 has been reported in a wide range of cancers, we investigated the molecular mechanisms of miR-98 during tumor progression. It has been reported that miR-98 mainly inhibits the tumor growth by the modulation of transcription factors and signaling pathways. Therefore, miR-98 can be introduced as a tumor marker and therapeutic target among cancer patients.

miR-214-PTEN pathway is a potential mechanism for stress-induced immunosuppression affecting chicken immune response to avian influenza virus vaccine

Stress-induced immunosuppression (SIIS) is one of common problems in the intensive poultry industry, affecting the effect of vaccine immunization and leading to high incidences of diseases. In this study, the expression characteristics and regulatory mechanisms of miR-214 in the processes of SIIS and its influence on the immune response to avian influenza virus (AIV) vaccine in chicken were explored. The qRT-PCR results showed that serum circulating miR-214 was significantly differentially expressed (especially on 2, 5, and 28 days post immunization (dpi)) in the processes, so had the potential as a molecular marker. MiR-214 expressions from multiple tissues were closely associated with the changes in circulating miR-214 expression levels. MiR-214-PTEN regulatory network was a potential key regulatory mechanism for the heart, bursa of Fabricius, and glandular stomach to participate in the process of SIIS affecting AIV immune response. This study can provide references for further understanding of stress affecting immune response.

EZH2-mediated development of therapeutic resistance in cancer

Enhancer of zeste homolog 2 (EZH2) regulates gene expression and plays a definite role in cell proliferation, apoptosis, and senescence. Overexpression of EZH2 has been found in various human malignancies, including prostate, breast, and ovarian cancers, and is associated with increased metastasis and poor prognosis. EZH2 catalyzes trimethylation of lysine 27 of histone H3 (H3K27me3) as a canonical role in a PRC2-dependent manner. This mechanism silences various tumor suppressor genes through EZH2-mediated histone lysine methyltransferase activity. As a non-canonical role, EZH2 partners with other signaling molecules to undergo post-translational modification to orchestrate its function as a co-activator playing a critical role in cancer progression. Dysregulation of EZH2 has also been associated with therapeutic resistance in cancer cells. Given the role of EZH2 in promoting carcinogenesis and therapy resistance, both canonical and non-canonical EZH2 inhibitors have been used to combat multiple cancer types. Moreover, combining EZH2 inhibitors with other therapeutic modalities have shown to enhance the therapeutic efficacy and overcome potential resistance mechanisms in these cancerous cells. Therefore, targeting EZH2 through canonical and non-canonical modes appears to be a promising therapeutic strategy to enhance efficacy and overcome resistance in multiple cancers.

MicroRNAs: A novel signature in the metastasis of esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a malignant epithelial tumor, characterized by squamous cell differentiation, it is the sixth leading cause of cancer-related deaths globally. The increased mortality rate of ESCC patients is predominantly due to the advanced stage of the disease when discovered, coupled with higher risk of metastasis, which is an exceedingly malignant characteristic of cancer, frequently leading to a high mortality rate. Unfortunately, there is currently no specific and effective marker to predict and treat metastasis in ESCC. MicroRNAs (miRNAs) are a class of small non-coding RNA molecules, approximately 22 nucleotides in length. miRNAs are vital in modulating gene expression and serve pivotal regulatory roles in the occurrence, progression, and prognosis of cancer. Here, we have examined the literature to highlight the intimate correlations between miRNAs and ESCC metastasis, and show that ESCC metastasis is predominantly regulated or regulated by genetic and epigenetic factors. This review proposes a potential role for miRNAs as diagnostic and therapeutic biomarkers for metastasis in ESCC metastasis, with the ultimate aim of reducing the mortality rate among patients with ESCC.

The Expression Patterns and Implications of MALAT1, MANCR, PSMA3-AS1 and miR-101 in Esophageal Adenocarcinoma

Esophageal adenocarcinoma (EAC) is a malignant tumor with poorly understood molecular mechanisms. This study endeavors to elucidate how the long non-coding RNAs (lncRNAs) MALAT1, MANCR and PSMA3-AS1, as well as the microRNA miR-101, exhibit specific expression patterns in the pathogenesis and prognosis of EAC. A total of 50 EAC tissue samples (tumors and lymph nodes) and a control group comprising 26 healthy individuals were recruited. The samples underwent quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analyses. The relative expression levels of MALAT1, MANCR, PSMA3-AS1, and miR-101 were ascertained and correlated with various clinicopathological parameters including TNM staging, tumor characteristics (size and grade of the tumor) lymphatic invasion, disease-free (DFS) and overall survival (OS) of EAC patients. Quantitative analyses revealed that MALAT1 and MANCR were significantly upregulated in EAC tumors and positive lymph nodes when compared to control tissues (p < 0.05). Such dysregulations correlated positively with advanced lymphatic metastases and a higher N stage. DFS in the subgroup of patients with negative lymph nodes was higher in the setting of low-MANCR-expression patients compared to patients with high MANCR expression (p = 0.02). Conversely, miR-101 displayed a significant downregulation in EAC tumors and positive lymph nodes (p < 0.05), and correlated negatively with advanced tumor stage, lymphatic invasion and the grade of the tumor (p = 0.006). Also, patients with low miR-101 expression showed a tendency towards inferior overall survival. PSMA3-AS1 did not demonstrate statistically significant alterations (p > 0.05). This study reveals MALAT1, MANCR, and miR-101 as putative molecular markers for prognostic evaluation in EAC and suggests their involvement in EAC progression.

A thorough and current study of miR-214-related targets in cancer

Cancer is a complex genetic anomaly involving coding and non-coding transcript structural and expressive irregularities. A class of tiny non-coding RNAs known as microRNAs (miRNAs) regulates gene expression at the post-transcriptional level by binding only to messenger RNAs (mRNAs). Due to their capacity to target numerous genes, miRNAs have the potential to play a significant role in the development of tumors by controlling several biological processes, including angiogenesis, drug resistance, metastasis, apoptosis, proliferation, and drug resistance. According to several recent studies, miRNA-214 has been linked to the emergence and spread of tumors. The human genome's q24.3 arm contains the DNM3 gene, which is about 6 kb away and includes the microRNA-214. Its primary purpose was the induction of apoptosis in cancerous cells. The multifaceted and complex functions of miR-214 as a modulator in neoplastic conditions have been outlined in the current review.

Epigenetic changes induced by pathogenic Chlamydia spp

Chlamydia trachomatis, C. pneumoniae, and C. psittaci, the three Chlamydia species known to cause human disease, have been collectively linked to several pathologies, including conjunctivitis, trachoma, respiratory disease, acute and chronic urogenital infections and their complications, and psittacosis. In vitro, animal, and human studies also established additional correlations, such as between C. pneumoniae and atherosclerosis and between C. trachomatis and ovarian cancer. As part of their survival and pathogenesis strategies as obligate intracellular bacteria, Chlamydia spp. modulate all three major types of epigenetic changes, which include deoxyribonucleic acid (DNA) methylation, histone post-translational modifications, and microRNA-mediated gene silencing. Some of these epigenetic changes may be implicated in key aspects of pathogenesis, such as the ability of the Chlamydia spp. to induce epithelial-to-mesenchymal transition, interfere with DNA damage repair, suppress cholesterol efflux from infected macrophages, act as a co-factor in human papillomavirus (HPV)-mediated cervical cancer, prevent apoptosis, and preserve the integrity of mitochondrial networks in infected host cells. A better understanding of the individual and collective contribution of epigenetic changes to pathogenesis will enhance our knowledge about the biology of Chlamydia spp. and facilitate the development of novel therapies and biomarkers. Pathogenic Chlamydia spp. contribute to epigenetically-mediated gene expression changes in host cells by multiple mechanisms.

DNA methylation of miR-138 regulates cell proliferation and EMT in cervical cancer by targeting EZH2

BACKGROUND

Emerging evidence has identified miR-138 as a tumor suppressor that can suppress the proliferation of various cancers. Meanwhile, the cause of abnormal miR-138 expression in cervical cancer remains uncertain. This study clarified the mechanism by which miR-138 regulates proliferation, invasion, metastasis, and EMT in cervical cancer cells.

RESULTS

miR-138 expression in human cervical cancer and adjacent normal tissue was measured using qPCR. SiHa and C33A cells were used to determine the function of miR-138 via miR-138 mimic or inhibitor transfection, followed by wound healing, Cell Counting Kit-8, flow cytometry, and Transwell assays. Epithelial and mesenchymal marker expression was analyzed using Western blotting. DNA methylation in the miR-138 promoter was examined using bisulfite sequencing PCR. The downstream target genes of miR-138 were identified via bioinformatics analysis and luciferase reporter assays. A tumor xenograft model was employed to validate DNA methylation-induced miR-138 downregulation and tumor growth inhibition in cervical cancer in vivo. miR-138 levels were significantly lower in cervical cancer tissues than in adjacent control tissues. Furthermore, lower miR-138 expression and higher CpG methylation in the miR-138 promoter were identified in lymph node-positive metastatic cervical cancer tumors versus that in non-metastatic tumor tissues. Upon miR-138 overexpression, cell proliferation, metastasis, invasion, and EMT were suppressed. miR-138 agomir transfection and demethylating drug treatment significantly inhibited cervical tumor growth and EMT in tumor xenograft models. DNA methylation inhibited miR-138 transcription, and enhancer of zeste homolog 2 (EZH2) downregulation mediated the tumor suppressor function of miR-138 in cervical cancer.

CONCLUSION

We demonstrated that miR-138 suppresses tumor progression by targeting EZH2 in cervical cancer and uncovered the role of DNA methylation in the miR-138 promoter in its downregulation. These findings demonstrated the potential of miR-138 to predict disease metastasis and/or function as a therapeutic target in cervical cancer.

Liquid Biopsy in Squamous Cell Carcinoma of the Esophagus and of the Head and Neck

Squamous cell carcinomas of the esophagus (ESCC) and of the head and neck (HNSCC) are two neoplasms that share common risk factors and have the same embryological origin, but a very different prognosis, the 5-year survival of HNSCC being almost double (40–50%) compared to the 5-year survival of ESCC (20%). Current guidelines emphasize the importance of screening for ESCC in patients diagnosed with head and neck cancers. A liquid biopsy is a novel tool for diagnosis, prognostic stratification, and personalized therapy. Liquid biopsy biomarkers for these two malignancies could help both their early detection, facilitate residual disease identification, and provide prognosis information. The present systematic review of the literature was aimed at describing the liquid biopsy biomarkers present in these two malignancies, with an emphasis on potential clinical applications.

The role of miR-101 in esophageal and gastric cancer

miR-101 is downregulated in various types of cancer, leading to the notion that miR-101 acts as a suppressor in cancer cell progression. The comprehensive mechanisms underlying the effects of miR-101 and the exact role of miR-101 dysregulations in esophagogastric tumors have not been fully elucidated. This review aims to summarize all current knowledge on the association between miR-101 expression and esophagogastric malignancies and to clarify the pathogenetic pathways and the possible prognostic and therapeutic role of miR-101 in those cancer types. miR-101 seems to play crucial role in esophageal and gastric cancer biology and tumorigenesis. It could also be a promising novel diagnostic and therapeutic target, as well as it may serve as a significant predictive biomarker in esophagogastric cancer.

Roles of MicroRNAs in Esophageal Squamous Cell Carcinoma Pathogenesis

MicroRNAs (miRNAs) are 20-22 nucleotides long single-stranded noncoding RNAs. They regulate gene expression posttranscriptionally by base pairing with the complementary sequences in the 3'-untranslated region of their targeted mRNA. Aberrant expression of miRNAs leads to alterations in the expression of oncogenes and tumor suppressors, thereby affecting cellular growth, proliferation, apoptosis, motility, and invasion capacity of gastrointestinal cells, including cells of esophageal squamous cell carcinoma (ESCC). Thus, alterations in miRNAs expression associated with the pathogenesis and progression of ESCC. In addition, expression profiles of miRNAs correlated with various clinicopathological factors, including pathological stages, histological differentiation, invasion, metastasis of cancer, as well as survival rates and therapy response of patients with ESCC. Consequently, expression profiles of miRNAs could be useful as diagnostic, prognostic, and prediction biomarkers in ESCC. Herein, we describe the quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and microarray methods for detection and quantitate miRNAs in ESCC. In addition, we summarize the roles of miRNAs in ESCC pathogenesis, progression, and prognosis.

A preliminary study of micro-RNAs as minimally invasive biomarkers for the diagnosis of prostate cancer patients

Background

A prostate cancer diagnosis is based on biopsy sampling that is an invasive, expensive procedure, and doesn’t accurately represent multifocal disease.

Methods

To establish a model using plasma miRs to distinguish Prostate cancer patients from non-cancer controls, we enrolled 600 patients histologically diagnosed as having or not prostate cancer at biopsy. Two hundred ninety patients were eligible for the analysis. Samples were randomly divided into discovery and validation cohorts.

Results

NGS-miR-expression profiling revealed a miRs signature able to distinguish prostate cancer from non-cancer plasma samples. Of 51 miRs selected in the discovery cohort, we successfully validated 5 miRs (4732-3p, 98-5p, let-7a-5p, 26b-5p, and 21-5p) deregulated in prostate cancer samples compared to controls (p ≤ 0.05). Multivariate and ROC analyses show miR-26b-5p as a strong predictor of PCa, with an AUC of 0.89 (CI = 0.83–0.95;p < 0.001). Combining miRs 26b-5p and 98-5p, we developed a model that has the best predictive power in discriminating prostate cancer from non-cancer (AUC = 0.94; CI: 0,835-0,954).

To distinguish between low and high-grade prostate cancer, we found that miR-4732-3p levels were significantly higher; instead, miR-26b-5p and miR-98-5p levels were lower in low-grade compared to the high-grade group (p ≤ 0.05).

Combining miR-26b-5p and miR-4732-3p we have the highest diagnostic accuracy for high-grade prostate cancer patients, (AUC = 0.80; CI 0,69-0,873).

Conclusions

Noninvasive diagnostic tests may reduce the number of unnecessary prostate biopsies.

The 2-miRs-diagnostic model (miR-26b-5p and miR-98-5p) and the 2-miRs-grade model (miR-26b-5p and miR-4732-3p) are promising minimally invasive tools in prostate cancer clinical management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01875-0.

LncRNA FAM83A-AS1 promotes ESCC progression by regulating miR-214/CDC25B axis

Background: Recent researches have pinpointed that long non-coding RNA (lncRNA) was tightly related to the carcinogenesis. However, the function of lncRNA in esophageal cell squamous carcinoma (ESCC) remains to be explored. In the current study, we assessed the expression pattern and the biological function of FAM83A-AS1 in ESCC.

Methods: qRT-PCR was used to detect the expression of FAM83A-AS1, miR-214, and CDC25B expression in ESCC tissues and cell lines. CCK-8, transwell, apoptosis and cell cycle assays were performed to define the function of FAM83A-AS1 in ESCC cells. Furthermore, the regulation of miR-214 by FAM83A-AS1 was defined by qRT- PCR and rescue assays. In addition, the association between CDC25B, miR-214, CDC25B was confirmed by qRT-PCR.

Results: Here, we discovered that FAM83A-AS1 was strongly expressed in ESCC tissues. FAM83A-AS1 abundance was associated with TNM stages and the differentiation grade of ESCC patients. The receiver operating characteristic curve (ROC) analysis indicated the high accuracy of FAM83A-AS1 in ESCC diagnosis. Functionally, inhibiting FAM83A-AS1 repressed cell proliferation, migration, and invasion in ESCC. In addition, we found that FAM83A-AS1 accelerated the cell cycle while inhibited cell apoptosis. Mechanistically, we found that FAM83A-AS1 regulated miR-214 expression, and there was a negative correlation between miR-214 and FAM83A-AS1 in ESCC. Rescue assay indicated that miR-214 could impair the suppressing effect of cell migration induced by FAM83A-AS1 depletion. Furthermore, CDC25B was a direct target of miR-214, and FAM83A-AS1 enhanced CDC25B expression while miR-214 positively CDC25B expression in ESCC.

Conclusions: Collectively, we concluded that FAM83A-AS1 facilitated ESCC progression by regulating the miR-214/CDC25B axis. Our study showed FAM83A-AS1 may act as a promising target for ESCC diagnosis and therapy.

LncRNA MIR205HG Drives Esophageal Squamous Cell Carcinoma Progression by Regulating miR-214/SOX4 Axis

Background

Esophageal squamous cell carcinoma (ESCC) is a common and fatal malignancy, which has posed a great challenge to public health, especially in China. Dysregulation of long non-coding RNAs is involved in the occurrence, development, invasion, and metastasis of multiple cancers including ESCC. However, little is known about the function of MIR205HG in ESCC.

Methods

We used qRT-PCR to detect the expression level of MIR205HG, miR-214, and SOX4 in human ESCC tissues and cell lines. Loss-of-functional assays were performed to test the impact of MIR205HG on cell proliferation, metastasis, and apoptosis process via CCK-8, transwell, and flow cell cytometry assays. Additionally, the downstream molecular mechanism of MIR205HG in ESCC was explored.

Results

Here, we found MIR205HG was substantially up-regulated in ESCC, and there was a positive correlation between MIR205HG expression and tumor size and lymphatic metastasis of ESCC patients. Inhibition of MIR205HG attenuated cell proliferation, migration, and invasion. Silencing MIR205HG increased G1 phase cell counts and decreased S phase cell counts, along with increased apoptotic cell populations. Notably, the rescue assays indicated that miR-214 could partly reverse the influence of MIR205HG on ESCC cell migration. We also found that SOX4 was a direct target mRNA of miR-214, and MIR205HG could act as a molecular sponge to regulate SOX4 expression in ESCC.

Conclusion

Taken together, our findings demonstrate that MIR205HG promotes ESCC progression by regulating the miR-214/SOX4 axis. MIR205HG may be a novel candidate target for ESCC diagnosis and therapy.

The microRNA cluster miR-214/miR-3120 prevents tumor cell switching from an epithelial to a mesenchymal-like phenotype and inhibits autophagy in gallbladder cancer

Tumor cells switch from an epithelial to a mesenchymal-like phenotype, which represents a key hallmark of human cancer metastasis, including gallbladder cancer (GBC). A large set of microRNAs (miRNAs/miRs) have been studied to elucidate their functions in initiating or inhibiting this phenotypic switching in GBC cells. In this paper, we attempted to identify the expression pattern of the miR-214/-3120 cluster and its mode of action in the context of GBC, with a specific focus being placed on their effects on EMT and autophagy in GBC cells. Human GBC cells GBC-SD were assayed for their migration, invasion, and autophagy using the Transwell chamber system, MDC staining, and transmission electron microscopy. The tumorigenicity and metastatic behavior of GBC-SD cells were tested in nude mice. The expression of EMT- and autophagy-specific markers (E-cadherin, N-cadherin, vimentin, ATG5, LC3II/LC3I, and Beclin1) was analyzed in cultured GBC-SD cells and in human GBC-SD xenografts. The E2F3 luciferase reporter activity in the presence of miR-214/-3120 was evaluated by a dual luciferase assay. The miR-214/-3120 was downregulated in GBC. Exogenous miR-214/-3120 inhibited the phenotypic switching of GBC cells from epithelial to mesenchymal, prevented autophagy, and suppressed the tumorigenicity and metastatic behavior of GBC-SD cells in vitro and in vivo. E2F3 was demonstrated to be the target gene of miR-214/-3120, and its knockdown in part mimicked the effect of miR-214/-3120 on the EMT, autophagy, tumorigenicity, and metastatic behavior of GBC-SD cells. These results demonstrated that the miR-214/-3120 cluster blocks the process of EMT and autophagy to limit GBC metastasis by repressing E2F3 expression.

Aberrantly upregulated FAM83H-AS1 facilitates malignant progression of esophageal squamous cell carcinoma

The biological roles of the newly identified long non-coding RNA family with sequence similarity 83 member H antisense 1 (FAM83H-AS1) in esophageal squamous cell carcinoma (ESCC) have remained largely elusive. In the present study, it was determined that, in comparison with paired para-tumorous tissues or normal esophageal epithelial cells, FAM83H-AS1 expression in cancer tissues and cell lines was markedly upregulated. Furthermore, FAM83H-AS1 expression was significantly elevated in patients with ESCC and lymph node metastasis or a late TNM stage, while no association with any other clinicopathological characteristics was detected. Furthermore, the overall and disease-free survival, as assessed by the Kaplan-Meier method, were significantly shortened in patients with high FAM83H-AS1 expression. A functional study then uncovered that knockdown of FAM83H-AS1 significantly suppressed the proliferation and migration of ESCC cells. The present results suggested that FAM83H-AS1 may facilitate the malignant progression of ESCC and may be utilized as a prognostic predictor and possibly a novel therapeutic target in ESCC that warrants further exploration.

Regulating Methylation at H3K27: A Trick or Treat for Cancer Cell Plasticity

Properly timed addition and removal of histone 3 lysine 27 tri-methylation (H3K27me3) is critical for enabling proper differentiation throughout all stages of development and, likewise, can guide carcinoma cells into altered differentiation states which correspond to poor prognoses and treatment evasion. In early embryonic stages, H3K27me3 is invoked to silence genes and restrict cell fate. Not surprisingly, mutation or altered functionality in the enzymes that regulate this pathway results in aberrant methylation or demethylation that can lead to malignancy. Likewise, changes in expression or activity of these enzymes impact cellular plasticity, metastasis, and treatment evasion. This review focuses on current knowledge regarding methylation and de-methylation of H3K27 in cancer initiation and cancer cell plasticity.

Carcinogenic roles and therapeutic effects of EZH2 in gynecological cancers

Enhancer of Zeste Homolog 2 (EZH2) is highly expressed in kinds of malignant tumors and related to tumor occurrence, development, and prognosis. EZH2 is the catalytic subunit of the polycomb repressive complex 2 (PRC2), which promotes cell proliferation, migration, and invasion by epigenetic regulation of anti-tumor gene. It can activate numerous tumor-associated signaling pathways and interfere with DNA damage repair. In recent years, large amounts of studies have shown that EZH2 is closely related to gynecologic-related malignancies and can be used as a potential target gene for the treatment of gynecological-related malignancies. This review summarizes the oncogenic function of EZH2 and introduces the recent advances in the development of EZH2 inhibitors. On this basis, future research prospect of EZH2 is proposed.

In silico prediction of potential miRNA-disease association using an integrative bioinformatics approach based on kernel fusion

Accumulating experimental evidence has demonstrated that microRNAs (miRNAs) have a huge impact on numerous critical biological processes and they are associated with different complex human diseases. Nevertheless, the task to predict potential miRNAs related to diseases remains difficult. In this paper, we developed a Kernel Fusion-based Regularized Least Squares for MiRNA-Disease Association prediction model (KFRLSMDA), which applied kernel fusion technique to fuse similarity matrices and then utilized regularized least squares to predict potential miRNA-disease associations. To prove the effectiveness of KFRLSMDA, we adopted leave-one-out cross-validation (LOOCV) and 5-fold cross-validation and then compared KFRLSMDA with 10 previous computational models (MaxFlow, MiRAI, MIDP, RKNNMDA, MCMDA, HGIMDA, RLSMDA, HDMP, WBSMDA and RWRMDA). Outperforming other models, KFRLSMDA achieved AUCs of 0.9246 in global LOOCV, 0.8243 in local LOOCV and average AUC of 0.9175 ± 0.0008 in 5-fold cross-validation. In addition, respectively, 96%, 100% and 90% of the top 50 potential miRNAs for breast neoplasms, colon neoplasms and oesophageal neoplasms were confirmed by experimental discoveries. We also predicted potential miRNAs related to hepatocellular cancer by removing all known related miRNAs of this cancer and 98% of the top 50 potential miRNAs were verified. Furthermore, we predicted potential miRNAs related to lymphoma using the data set in the old version of the HMDD database and 80% of the top 50 potential miRNAs were confirmed. Therefore, it can be concluded that KFRLSMDA has reliable prediction performance.

Circulatory miR-98-5p levels are deregulated during diabetes and it inhibits proliferation and promotes apoptosis by targeting PPP1R15B in keratinocytes

Although deregulated circulatory miRNA signatures during diabetes have been identified for some years now, the effects of such miRNAs on several target tissues are not yet thoroughly investigated. The skin that is nourished by components present in the circulation exhibits several notable abnormal features during diabetes. We, therefore, hypothesized that such altered circulatory miRNA levels might be critical in the onset and progression of impaired skin health during diabetes. RNA sequencing from blood samples of normal and type 2 diabetic human subjects identified 9 upregulated and 19 downregulated miRNAs. miR-98-5p was significantly downregulated and its overexpression down-regulated PPP1R15B levels in HaCaT cells and this was prevented by the miR-98-5p inhibitor. This was validated in human primary epidermal keratinocytes and further supported by a dual reporter luciferase assay of the PPP1R15B 3'UTR where miR-98-5p significantly decreased the luciferase activity which was prevented in the presence of the miRNA inhibitor and by mutation in the miRNA binding site. By targeting PPP1R15B, miR-98-5p increases levels of p-eIF2α, BiP and CHOP. Consequently, there was induction of apoptosis accompanied with decreased proliferation in the presence of miR-98-5p. Conversely, miR-98-5p inhibition alone inhibited apoptosis and promoted proliferation. Taken together, our data suggest that by targeting PPP1R15B, miR-98-5p induces apoptosis and decreases proliferation. As opposed to this since circulatory miR-98-5p levels are decreased in diabetes, we believe that this decrease in the circulation that feeds the skin layers might be a major contributor of hyperproliferation as seen in the skin during diabetes.Abbreviations: miRNAs: MicroRNAs; PPP1R15B: PPP1R15B: Protein Phosphatase 1 Regulatory Subunit 15B; TGFβR1: Transforming Growth Factor Beta Receptor 1; ER: Endoplasmic Reticulum; Bip: Binding Immunoglobulin Protein; Chop: CCAAT-enhancer-binding protein homologous protein; p-eIF2α: Eukaryotic Translation Initiation Factor 2a; Bax: Bcl2-associated X protein; Bcl-2: B-cell CLL/lymphoma 2; PCNA: Proliferating Cell Nuclear Antigen; K5: Cytokeratin 5; qRT-PCR: Quantitative Real-Time PCR; ESCC: Oesophageal squamous cell carcinoma; HCC: Hepatocellular carcinoma; CTHRC1: Collagen triple helix repeat containing 1; SALL4: Sal-like protein 4; TNFα: Tumour Necrosis Factor alpha; PGC-1β: Peroxisome Profilerator-activated receptor-γ coactivator-1β; IGF2BP1: Insulin-like growth factor 2 mRNA binding protein 1.

Involvement of noncoding RNAs in epigenetic modifications of esophageal cancer

Esophageal cancer (EC) is a serious digestive malignancy and is a leading cause of cancer-related mortality. Apart from genetic mutations, many epigenetic alterations including DNA methylation and histone modifications associated with chromatin remodeling have been identified in the regulation of gene expression in EC. Recently, noncoding RNAs, and mainly lncRNAs and miRNAs, have been revealed to be involved in the epigenetic regulation of EC. In this review, we focus on describing new insights on epigenetic processes associated with noncoding RNAs, which have been characterized to be responsible for the development and progression of EC.

MicroRNA-214 targets PTK6 to inhibit tumorigenic potential and increase drug sensitivity of prostate cancer cells

Prostate cancer is the most commonly diagnosed cancer in men with African American men disproportionally suffering from the burden of this disease. Biomarkers that could discriminate indolent from aggressive and drug resistance disease are lacking. MicroRNAs are small non-coding RNAs that affect numerous physiological and pathological processes, including cancer development and have been suggested as biomarkers and therapeutic targets. In the present study, we investigated the role of miR-214 on prostate cancer cell survival/migration/invasion, cell cycle regulation, and apoptosis. miR-214 was differentially expressed between Caucasian and African American prostate cancer cells. Importantly, miR-214 overexpression in prostate cancer cells induced apoptosis, inhibiting cell proliferation and colony forming ability. miR-214 expression in prostate cancer cells also inhibited cell migration and 3D spheroid invasion. Mechanistically, miR-214 inhibited prostate cancer cell proliferation by targeting protein tyrosine kinase 6 (PTK6). Restoration of PTK6 expression attenuated the inhibitory effect of miR-214 on cell proliferation. Moreover, simultaneous inhibition of PTK6 by ibrutinib and miR-214 significantly reduced cell proliferation/survival. Our data indicates that miR-214 could act as a tumor suppressor in prostate cancer and could potentially be utilized as a biomarker and therapeutic target.

MicroRNA‑214 suppresses the viability, migration and invasion of human colorectal carcinoma cells via targeting transglutaminase 2

Colorectal carcinoma (CRC) is a common malignancy of the digestive tract. MicroRNA (miR)-214 is considered a key hub that controls tumor networks; therefore, the effects of miR-214 on CRC were examined and its target gene was investigated in this study. The expression levels of transglutaminase 2 (TGM2) and miR-214 were detected in CRC and adjacent normal tissues by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting, and luciferase activity was analyzed by dual luciferase reporter analysis. In addition, cell viability, invasion and migration were measured by Cell Counting kit-8 and Transwell assays, respectively. The expression levels of epithelial-mesenchymal transition-related proteins, and phosphoinositide-3 kinase (PI3K)/protein kinase B (Akt) signaling-associated factors were detected using RT-qPCR and western blotting. The results demonstrated that miR-214 expression was downregulated in CRC tissue, whereas TGM2 expression was upregulated. According to TargetScan prediction, miR-214 possesses a binding site to TGM2. In addition, transfection with miR-214 mimics markedly suppressed the viability of LoVo cells. miR-214 overexpression also inhibited cell invasion and migration by increasing E-cadherin and tissue inhibitor of metalloproteinases-2 expression, and decreasing matrix metalloproteinase (MMP)-2 and MMP-9 expression. Furthermore, miR-214 downregulated phosphorylation of PI3K and Akt; however, the expression levels of total PI3K and Akt were not affected by miR-214. In conclusion, this study indicated that TGM2 was a target gene of miR-214, and a negative correlation between miR-214 and TGM2 expression was determined in CRC. Notably, miR-214 markedly suppressed the viability, invasion and migration of CRC cells, which may be associated with a downregulation in PI3K/Akt signaling. These findings suggested that miR-214 may be considered a novel target for the treatment of CRC.

Down-regulation of microRNA-98 promoted apoptosis of TNF-α stimulated human fibroblast-like synoviocytes via up-regulating IL-10

In this study, we constructed a tumor necrosis factor α (TNF-α)-induced synovial cell inflammatory model using human synoviocytes (HS) cell line to explore the function of miR-98 in rheumatoid arthritis (RA). miR-98 mimics or miR-98 inhibitor were transfected into HS cells to up-regulate or down-regulate the expression of miR-98. The proliferation and apoptosis of HS cells were determined using CCK8 assay and flow cytometry, respectively. TargetScan website was utilized to predict the targets of miR-98. Luciferase assay was carried out to verify that IL-10 is a target of miR-98. Western blot was performed to analyze the expression of IL-10, apoptosis-related and NF-κB signaling pathway-related proteins. Our results demonstrated that the expression of miR-98 was up-regulated in HS cells stimulated by TNF-α. Down-regulation of miR-98 by inhibitor in TNF-α-stimulated HS cells dramatically inhibited cell proliferation and promoted cell apoptosis compared with the miR-98 inhibitor NC group. The protein expression of Bcl-2 was declined while the levels of Bax and Bim were increased by miR-98 inhibitor in TNF-α-stimulated HS cells. IL-10 was predicted and verified as a target of miR-98. qRT-PCR and western blot results revealed that the level of IL-10 was negatively regulated by miR-98. Finally, we identified that down-regulation of miR-98 reduced the expression level of p-p65 and p-IκBα in TNF-α-stimulated HS cells. In summary, our present study demonstrated that down-regulation of miR-98 inhibited the proliferation and promoted the apoptosis of TNF-α-stimulated HS partly by targeting IL-10 and regulating NF-κB signaling pathway, insinuating miR-98 as a candidate biomarker in RA.

Overexpression of miR-98 attenuates neuropathic pain development via targeting STAT3 in CCI rat models

MicroRNA (miRNA) are significant regulators of neuropathic pain development and neuroinflammation can contribute a lot to the progression of neuropathic pain. Recently, miR-98 has been reported to be involved in various diseases. However, little is known about the role of miR-98 in neuropathic pain development and neuroinflammation. Therefore, our study was aimed to investigate the function of miR-98 in neuropathic pain via establishing a rat model using chronic constriction injury (CCI) of the sciatic nerve. Here, we observed that miR-98 was downregulated in CCI rat models. Overexpression of miR-9 was able to inhibit neuropathic pain progression. Recently, STAT3 has been reported to serve a key role in various processes, including inflammation. Interestingly, our study indicated that STAT3 was dramatically upregulated and activated in CCI rats. By using informatics analysis, STAT3 was predicted as a direct target of miR-98 and the direct correlation was confirmed. Then, miR-98 was overexpressed in CCI rats and it was found that miR-98 was able to repress neuropathic pain development via inhibiting the neuroinflammation. As displayed, interleukin 6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α) expression was obviously induced in CCI rats, while miR-98 reduced their protein levels. Finally, we found that overexpression of STAT3 reversed the inhibitory effect of miR-98 on neuropathic pain development. Taken these together, we reported that overexpression of miR-98 attenuated neuropathic pain development via targeting STAT3 in CCI rat models.

Overexpression of microRNA-98 inhibits cell proliferation and promotes cell apoptosis via claudin-1 in human colorectal carcinoma

Colorectal carcinoma (CRC) is a major cause of cancer-related deaths worldwide, and investigations on novel targets are imperative. MiR-98 has been reported to act as a tumor suppressor in several cancers. To evaluate miR-98 as a novel anticancer molecule for CRC, examinations to validate whether miR-98 conferred an inhibiting effect on proliferation, migration, and invasion were performed. The microarray-based gene expression profiling involving CRC was used to identify the differentially expressed genes. The potential relationship between miR-98 and CLDN1 was analyzed by cell experimentation. Then, the CRC cells were transfected with miR-98 mimic or miR-98 inhibitor to investigate the potential effect of miR-98 overexpression and depletion on CRC cell proliferation, migration, invasion, and apoptosis. The expressions of CLDN1, Bcl-2 associated protein x (Bax), runt-related transcription factor 3 (RUNX3), B-cell lymphoma 2 (Bcl-2), C-myc, and proliferating cell nuclear antigen (PCNA) were determined. The downregulated miR-98 along with an upregulated CLDN1 was observed in CRC, in which miR-98 could target to regulate CLDN1. The overexpression of miR-98 or silencing of CLDN1 was shown to increase the expression of Bax and RUNX3 along with promoted cell apoptosis and arrested cells in G1 phase, while decreasing the expression of CLDN1, Bcl-2, C-myc, and PCNA with suppressed proliferation, migration, and invasion. Collectively, the current study supports the notion that miR-98 plays an inhibitory role in human CRC cell proliferation, migration, and invasion and act as a contributor for cell apoptosis by downregulating CLDN1. The current study highlights a potential future strategy to help prevent the development of CRC.

Circular RNA ATXN7 is upregulated in non-small cell lung cancer and promotes disease progression

Circular RNAs (circRNAs) are a class of endogenous non-coding RNAs that is generated from back-splicing, and is characterized by a covalent closed loop without 3′ and 5′ ends. Recently, the biological function of circRNAs has received increasing attention; however, studies on circRNAs in non-small cell lung cancer (NSCLC) have rarely been reported. In the present study, the expression profiles of circRNAs in NSCLC were investigated, and the association between the circular RNA ATXN7 (circATXN7) expression level and clinicopathological characteristics of patients with NSCLC was assessed. In addition, the effects of circATXN7 on cell proliferation and invasion were examined. The results revealed that circATXN7 was upregulated in 45 NSCLC tissues compared with its expression in non-tumor tissues. However, there was no marked difference between the expression level of circATXN7 and the majority of the examined clinicopathological characteristics. It was also observed that the survival time of patients with high circATXN7 levels was shorter compared with that of patients with low circATXN7 levels, although the difference was not statistically significant (P>0.05). Furthermore, silencing of circATXN7 by small interfering RNA inhibited the proliferation and invasion of NSCLC cells in vitro. Taken together, the present study was the first to identify that circATXN7 was upregulated in NSCLC tumor tissues. Furthermore, the downregulation of circATXN7 markedly inhibited the proliferation and invasion abilities of NSCLC cells.

Assessment of miR-98-5p, miR-152-3p, miR-326 and miR-4289 Expression as Biomarker for Prostate Cancer Diagnosis

Prostate cancer (PCa) is one of the most commonly diagnosed cancers worldwide, accounting for almost 1 in 5 new cancer diagnoses in the US alone. The current non-invasive biomarker prostate specific antigen (PSA) has lately been presented with many limitations, such as low specificity and often associated with over-diagnosis. The dysregulation of miRNAs in cancer has been widely reported and it has often been shown to be specific, sensitive and stable, suggesting miRNAs could be a potential specific biomarker for the disease. Previously, we identified four miRNAs that are significantly upregulated in plasma from PCa patients when compared to healthy controls: miR-98-5p, miR-152-3p, miR-326 and miR-4289. This panel showed high specificity and sensitivity in detecting PCa (area under the curve (AUC) = 0.88). To investigate the specificity of these miRNAs as biomarkers for PCa, we undertook an in depth analysis on these miRNAs in cancer from the existing literature and data. Additionally, we explored their prognostic value found in the literature when available. Most studies showed these miRNAs are downregulated in cancer and this is often associated with cancer progression and poorer overall survival rate. These results suggest our four miRNA signatures could potentially become a specific PCa diagnostic tool of which prognostic potential should also be explored.

Epigenetic Regulation of EMT (Epithelial to Mesenchymal Transition) and Tumor Aggressiveness: A View on Paradoxical Roles of KDM6B and EZH2

EMT (epithelial to mesenchymal transition) is a plastic phenomenon involved in metastasis formation. Its plasticity is conferred in a great part by its epigenetic regulation. It has been reported that the trimethylation of lysine 27 histone H3 (H3K27me3) was a master regulator of EMT through two antagonist enzymes that regulate this mark, the methyltransferase EZH2 (enhancer of zeste homolog 2) and the lysine demethylase KDM6B (lysine femethylase 6B). Here we report that EZH2 and KDM6B are overexpressed in numerous cancers and involved in the aggressive phenotype and EMT in various cell lines by regulating a specific subset of genes. The first paradoxical role of these enzymes is that they are antagonistic, but both involved in cancer aggressiveness and EMT. The second paradoxical role of EZH2 and KDM6B during EMT and cancer aggressiveness is that they are also inactivated or under-expressed in some cancer types and linked to epithelial phenotypes in other cancer cell lines. We also report that new cancer therapeutic strategies are targeting KDM6B and EZH2, but the specificity of these treatments may be increased by learning more about the mechanisms of action of these enzymes and their specific partners or target genes in different cancer types.

Identification of miRNA profiling in prediction of tumor recurrence and progress and bioinformatics analysis for patients with primary esophageal cancer: Study based on TCGA database

OBJECT

This study focused on the identification of prognostic miRNAs for the prediction of tumor recurrence and progress in esophageal cancer.

METHODS

MiRNA profiling and clinical characteristics of esophageal cancer patients was downloaded from the TCGA database. Univariate analysis was performed to select potential prognostic miRNAs and covariates. LASSO based logistic regression was conducted to identify the prognostic miRNAs given covariates. Bioinformatics analysis including gene ontology, disease ontology and pathway enrichment analysis were performed. A nomogram was generated based on multivariate logistic regression to illustrate the association between the identified miRNAs and the risk of tumor recurrence and progress.

RESULTS

A total of 1881 miRNAs and 10 clinical characteristics were obtained from TCGA database. 18 miRNAs were finally identified in which 6 miRNAs were identified for the first time to be associated with the tumor recurrence and progress of esophageal cancer given covariates. Bioinformatics analysis suggested that the identified miRNAs were associated with the tumor recurrence and progress of esophageal cancer. The association between identified miRNAs and risk of tumor recurrence and progress were presented in a nomogram.

CONCLUSION

The 6 newly identified miRNAs may be potential biomarkers for the prediction of tumor recurrence and progress of esophageal cancer.

Stabilization of miRNAs in esophageal cancer contributes to radioresistance and limits efficacy of therapy

The five-year survival rate of esophageal cancer patients is less than 20%. This may be due to increased resistance (acquired or intrinsic) of tumor cells to chemo/radiotherapies, often caused by aberrant cell cycle, deregulated apoptosis, increases in growth factor signaling pathways, and/or changes in the proteome network. In addition, deregulation in non-coding RNA-mediated signaling pathways may contribute to resistance to therapies. At the molecular level, these resistance factors have now been linked to various microRNA (miRNAs), which have recently been shown to control cell development, differentiation and neoplasia. The increased stability and dysregulated expression of miRNAs have been associated with increased resistance to various therapies in several cancers, including esophageal cancer. Therefore, miRNAs represent the next generation of molecules with tremendous potential as biomarkers and therapeutic targets. However, detailed studies on miRNA-based therapeutic interventions are still in their infancy. Hence, in this review, we have summarized the current status of microRNAs in dictating the resistance/sensitivity of tumor cells to chemotherapy and radiotherapy. In addition, we have discussed various strategies to increase radiosensitivity, including targeted therapy, and the use of miRNAs as radiosensitive/radioresistance biomarkers for esophageal cancer in the clinical setting.

Role of miR-214 in modulating proliferation and invasion of human colon cancer SW620 cells

This study investigated the role of miR-214 in modulating proliferation and invasion of human colon cancer SW620 cells. Fifty-five patients with colon cancer who were treated in China-Japan Union Hospital of Jilin University from March 2014 to March 2015 were enrolled into this study. Their cancer and corresponding paracancerous tissues were collected and the expression levels of miR-214 were determined by RT-qPCR. A miR-214 expression vector was constructed. SW620 cells were transfected with the miR-214 expression vector and a blank vector. Cells transfected with the miR-214 expression vector were assigned to the miR-214 positive group and cells transfected with the blank vector were assigned to the miR-214 negative group. Cell proliferation, invasion and apoptosis were assessed by MTT assay, Transwell migration assay and TUNEL apoptosis assay, respectively. The RT-qPCR results showed that the expression level of miR-214 in colon cancer tissue, as well as in miR-214 negative cells, was significantly lower than that in paracancerous tissue (P<0.05 for both). In cell comparison, the expression level of miR-214 in the miR-214 positive group was significantly higher than that in the miR-214 negative group (0.483±0.001 vs. 0.172±0.001; P<0.05). The proliferation level of SW620 cells in the miR-214 positive group was lower than that in the miR-214 negative group (P<0.05). The Transwell migration assay indicated that there were less cells penetrating the membrane in the miR-214 positive group than in the miR-214 negative group (P<0.05). In addition, The apoptosis rate of cells in the miR-214 negative group was significantly lower than that in the miR-214 positive group (P<0.05). Finally, the low expression of miR-214 was found in colon cancer, indicating that miR-214 is a cancer suppressor playing an opposing role in colon cancer onset and progression. Therefore, miR-214 can promote apoptosis of colon cancer cells SW620 by inhibiting their proliferation and invasion.

miR-214 regulates papillary thyroid carcinoma cell proliferation and metastasis by targeting PSMD10

MicroRNAs (miRNAs) have important effects on cancer occurrence and development by adjusting gene expression. The aim of the present study was to examine the role of miR-214 in papillary thyroid carcinoma cell proliferation and metastasis, and its molecular mechanisms. miR-214 was demonstrated to be markedly downregulated in papillary thyroid carcinoma tissues and cells compared with normal, and this was significantly associated with lymph node metastasis, tumor size and TNM stage. Upregulation of miR-214 significantly decreased cell proliferation, and promoted cell apoptosis and cell cycle arrest in papillary thyroid carcinoma cell lines in vitro. By contrast, downregulation of miR-214 resulted in the opposite effects. In addition, miR-214 mimics significantly decreased papillary thyroid carcinoma cell migration and invasion, which was correlated with decreased expression levels of matrix metallopeptidase (MMP)-2 and MMP-9. Restoration of miR-214 expression in papillary thyroid carcinoma cells decreased the activities associated with epithelial-mesenchymal transition (EMT). Furthermore, proteasome 26S subunit non-ATPase 10 (PSMD10) was predicted to be a target of miR-214. Experimental results demonstrated that miR-214 negatively regulated PSMD10 expression by targeting its 3′ untranslated region directly. Knockdown of PSMD10 reduced papillary thyroid carcinoma cell clone formation, migration and invasion, most likely by repressing glycogen synthase kinase (GSK)-3β/β-catenin and AKT signaling. Finally, a negative correlation was observed between the expression levels of miR-214 and PSMD10 in papillary thyroid carcinoma tissues. Taken together, these data suggested that miR-214 might be a candidate target for the treatment of papillary thyroid carcinoma.

Circ0043898 acts as a tumor inhibitor and performs regulatory effect on the inhibition of esophageal carcinoma

Objective: The study aimed to investigate candidate circular RNAs (circRNAs) in regulating the pathogenic process of esophageal carcinoma. Methods: Specimens were collected from the patients with esophageal carcinoma. Total RNA was purified and treated with RNase R followed by RNA-seq in the purpose of screening the circRNAs in significant differentially expression. The expression level of the screened circRNAs were further validated using RT-PCR. The circular structure of the circRNA was validated with divergent and convergent primers. Overexpression vector was prepared in the purpose of raising the expression level of circ0043898 in the ECA-109 and Kyse-520 cells. The cell colony assay and MTS assay were conducted to determine the capacity of cell proliferation. Chamber assays were applied to determine the capacity of cell migration and invasion while flowcytometry was applied to determine the cell cycle and cell apoptosis. In vivo animal assay was conducted by injecting the cells to the chest of the mice. RNA-seq was performed followed by GO and KEGG study to further verify the regulation mechanism of circ0043898. Results: circ0043898 was validated that down-regulated expressed in the specimens from the patients with esophageal carcinoma. The cell assays proved that overexpression of circ0043898 can obviously inhibit the cell proliferation, cell migration and invasion and induce cell apoptosis and death in the cancerous cells. The in vivo animal study also suggested that the circ0043898 performed inhibitory functions on oncogenesis. The RNA-seq presented the potential regulation mechanism of circ0043898. Histone H3 and BMI1 were presented significantly differential expression in both ECA-109 and Kyse-520 cells, indicating they might be the targets of circ0043898. Conclusion: circ0043898 is presented as tumor inhibitor and could be a candidate biomarker in the therapeutic target and diagnosis of esophageal carcinoma.

COL1A1: A potential therapeutic target for colorectal cancer expressing wild-type or mutant KRAS

Colorectal cancer (CRC) treatment primarily relies on chemotherapy along with surgery, radiotherapy and, more recently, targeted therapy at the late stages. However, chemotherapeutic drugs have high cytotoxicity, and the similarity between the effects of these drugs on cancerous and healthy cells limits their wider use in clinical settings. Targeted monoclonal antibody treatment may compensate for this deficiency. Epidermal growth factor receptor (EGFR)-targeted drugs have a positive effect on CRC with intact KRAS proto-oncogene GTPase (KRAS or KRAS^WT), but may be ineffective or harmful in patients with KRAS mutations (KRAS^MUT). Therefore, it is important to identify drug target genes that are uniformly effective with regards to KRAS^WT and KRAS^MUT CRC. The present study performed gene expression analysis, and identified 294 genes upregulated in KRAS^WT and KRAS^MUT CRC samples. Collagen type I α 1 (COL1A1) was identified as the hub gene through STRING and Cytoscape analyses. Consistent with results obtained from Oncomine, a cancer microarray database and web-based data-mining platform, it was demonstrated that the expression of COL1A1 was significantly upregulated in CRC tissues and cell lines regardless of KRAS status. Inhibition of COL1A1 in KRAS^WT and KRAS^MUT CRC cell lines significantly decreased cell proliferation and invasion. In addition, increased COL1A1 expression in CRC was significantly associated with serosal invasion, lymph metastases and hematogenous metastases. Taken together, the findings of the present study indicated that COL1A1 may serve as a candidate diagnostic biomarker and a promising therapeutic target for CRC.

Downregulated miR-98-5p promotes PDAC proliferation and metastasis by reversely regulating MAP4K4

BACKGROUND

The aberrant expression of microRNAs (miRNAs) has emerged as important hallmarks of cancer. However, the molecular mechanisms underlying the differences of miRNA expression remain unclear. Many studies have reported that miR-98-5p plays vital functions in the development and progression of multiple cancers. However, its role in pancreatic ductal adenocarcinoma (PDAC) remains unknown.

METHODS

The expression of miR-98-5p and its specific target gene were determined in human PDAC specimens and cell lines by miRNA qRT-PCR, qRT-PCR and western blot. The effects of miR-98-5p depletion or ectopic expression on PDAC proliferation, migration and invasion were evaluated in vitro using CCK-8 proliferation assays, colony formation assays, wound healing assays and transwell assays. Furthermore, the in vivo effects were investigated using the mouse subcutaneous xenotransplantation and pancreatic tail xenotransplantation models. Luciferase reporter assays were employed to identify interactions between miR-98-5p and its specific target gene.

RESULTS

MiR-98-5p expression was significantly lower in cancerous tissues and associated with tumor size, TNM stage, lymph node metastasis and survival. Notably, a series of gain- and loss-of-function assays elucidated that miR-98-5p suppressed PDAC cell proliferation, migration and invasion both in vitro and in vivo. Luciferase reporter assays, western blot and qRT-PCR revealed MAP4K4 to be a direct target of miR-98-5p. The effects of ectopic miR-98-5p were rescued by MAP4K4 overexpression. In contrast, the effects of miR-98-5p depletion were impaired by MAP4K4 knockdown. Furthermore, miR-98-5p suppressed the MAPK/ERK signaling pathway through downregulation of MAP4K4. In addition, the expression level of miR-98-5p was negatively correlated with MAP4K4 expression in PDAC tissues and cell lines.

CONCLUSIONS

These results suggest that downregulation of miR-98-5p promotes tumor development by downregulation of MAP4K4 and inhibition of the downstream MAPK/ERK signaling, thus, highlighting the potential of miR-98-5p as a therapeutic target for PDAC.

EZH2 induces the expression of miR-1301 as a negative feedback control mechanism in triple negative breast cancer

Breast cancer is one of the most common malignancies in women. ERα, PR, and HER2 triple negative breast cancer (TNBC) is the current research focus because of the lack of effective targeted therapies. In our study, lentivirus systems were used to overexpress EZH2 and miR-1301 in TNBC cell lines. Western blot analysis and RT-qPCR were used to detect the protein and microRNA levels. The TCGA and Kaplan Meier plotter databases were used to analyze the EZH2 and miR-1301 expression levels in breast cancer. The effect of miR-1301 overexpression on cell proliferation, migration and colony formation were determined by using the sulforhodamine B (SRB) assay, wound healing assay and colony formation assay, respectively. Furthermore, an xenograft mouse model was used to investigate the function of miR-1301 overexpression in vivo. Finally, dual luciferase reporter assay was used to verify the binding site of EZH2 and miR-1301. We found that EZH2 induced the expression of miR-1301 in two TNBC cell lines, HCC1937 and HCC1806. Overexpression of miR-1301 suppressed TNBC cell proliferation, migration and colony formation, as well as the xenograft tumor growth in immunodeficient mice. Interestingly, miR-1301 inhibited the expression of EZH2 by binding to the 3'-UTR of EZH2 gene. These data suggest that EZH2 induces the expression of miR-1301 as a negative feedback control mechanism in TNBC.

Low serum miR-98 as an unfavorable prognostic biomarker in patients with non-small cell lung cancer

BACKGROUND

Blood-circulating miRNAs have been reported to act as potential biomarkers in various cancers including non-small cell lung cancer (NSCLC).

OBJECTIVE

This study was to assess serum miR-98 levels in NSCLC patients and explore its potential prognostic value.

METHODS

The relative expression levels of miR-98 were detected by quantitative RT-PCR in the sera of 127 NSCLC patients and 60 healthy controls.

RESULTS

Our results showed that serum miR-98 expression was down-regulated in NSCLC patients compared with healthy controls. Receiver operating characteristic (ROC) curve analysis suggested that serum miR-98 could be used as a potential marker in the diagnosis of NSCLC. In addition, decreased serum miR-98 was positively correlated with worse TNM stage, lymph node metastasis, as well as unfavorable overall survival. Multivariate Cox regression analysis confirmed that serum miR-98 expression was an independent prognostic factor for NSCLC.

CONCLUSIONS

Therefore, serum miR-98 might be useful as a promising biomarker for prognosis prediction of NSCLC.

Chaperonin-containing T‑complex protein 1 subunit 8 promotes cell migration and invasion in human esophageal squamous cell carcinoma by regulating α-actin and β-tubulin expression

The chaperonin-containing T‑complex protein 1 (CCT) has eight subunits, CCT 1-8, which are dysregulated in several types of cancer. To determine how subunit 8 (CCT8) influences the development of esophageal squamous cell carcinoma (ESCC), immunohistochemistry and western blot analysis were performed on 128 ESCC samples in the present study to measure the expression of CCT8. The prognostic value of CCT8 was analyzed using univariate and multivariate survival analyses. CCT8 knockdown in ESCC cells was performed and subsequently, the migration and invasion of ESCC cells was assessed. The results of immunohistochemistry and western blot analysis of ESCC tissue indicated that the expression of CCT8 in tumor tissues from patients with lymph node metastasis (LNM) was high whereas its expression in tissues from those without LNM was low. In addition, the overall survival rate of patients with high CCT8 expression was poor. It was demonstrated that CCT8 influenced the migration and invasion of ESCC cells by regulating α-actin and β-tubulin. Following CCT8 knockdown, cells were treated with cisplatin; it was demonstrated that α-actin and β-tubulin were downregulated and that cell apoptosis was enhanced. These data confirm that α-actin and β-tubulin are regulated by CCT8, and that increased CCT8 expression is associated with poor patient prognosis and cisplatin resistance in ESCC.

MicroRNA-1 suppresses proliferation, migration and invasion by targeting Notch2 in esophageal squamous cell carcinoma

MicroRNAs play an important role in the migration and invasion of tumors, and lower expression of microRNA-1 (miR-1) has been proven in a variety of malignant tumors, including esophageal squamous cell carcinoma (ESCC). In this study, we found that miR-1 expression levels in tumor tissues and preoperative serum from esophageal carcinoma patients were lower than those in non-tumorous tissues and healthy volunteers. miR-1 expression in tissues and plasma was closely related to invasion, lymph node metastasis and TNM staging. Additionally, miR-1 expression levels in tissues and plasma were positively correlated. miR-1 inhibited cell proliferation, migration and invasion. Overexpression of miR-1 in ESCC cells reduced Notch2 protein but not mRNA levels, whereas suppression of miR-1 led to an increase in Notch2 protein but not mRNA levels. A dual-luciferase experiment validated that Notch2 was a direct target of miR-1. Introducing Notch2 mRNA into cells over-expressing miR-1 partially abrogated the effects of miR-1 on migration and invasion. Further studies verified that miR-1 regulates EMT signalling pathways directly through Notch2. Therefore, these results confirm that, as a tumor suppressor gene, miR-1 may be a potential tumor marker for the early diagnosis of ESCC and a new drug target.

MicroRNAs in esophageal squamous cell carcinoma: Potential biomarkers and therapeutic targets

Esophageal cancer is a common cause of cancer-related deaths worldwide. Squamous cell carcinoma (SCC) is the major histological type of esophageal cancer in developing countries including China, and the prognosis is very poor. Many microRNAs are involved in several important biological and pathologic processes, and promote tumorigenesis. To better understand the prognostic and therapeutic roles of microRNAs in ESCC, we reviewed the diagnosis and prognosis associated oncogenic microRNAs (e.g. miR-21 and miR-17-92 cluster) and tumor suppressor microRNAs (e.g. miR-375, miR-133a and miR-133b), and diagnosis and prognosis associated oncogenic target genes (e.g. PDCD4 and CCND1) and tumor suppressor target genes (e.g. EZH2 and PDK1). We also summarized the prognostic microRNA and target gene pairs (e.g. miR-296 and CCND1, miR214 and EZH2). Taken together, our review highlights the opportunities and challenges for microRNAs in the molecular diagnosis and target therapy of ESCC.

HGIMDA: Heterogeneous graph inference for miRNA-disease association prediction

Recently, microRNAs (miRNAs) have drawn more and more attentions because accumulating experimental studies have indicated miRNA could play critical roles in multiple biological processes as well as the development and progression of human complex diseases. Using the huge number of known heterogeneous biological datasets to predict potential associations between miRNAs and diseases is an important topic in the field of biology, medicine, and bioinformatics. In this study, considering the limitations in the previous computational methods, we developed the computational model of Heterogeneous Graph Inference for MiRNA-Disease Association prediction (HGIMDA) to uncover potential miRNA-disease associations by integrating miRNA functional similarity, disease semantic similarity, Gaussian interaction profile kernel similarity, and experimentally verified miRNA-disease associations into a heterogeneous graph. HGIMDA obtained AUCs of 0.8781 and 0.8077 based on global and local leave-one-out cross validation, respectively. Furthermore, HGIMDA was applied to three important human cancers for performance evaluation. As a result, 90% (Colon Neoplasms), 88% (Esophageal Neoplasms) and 88% (Kidney Neoplasms) of top 50 predicted miRNAs are confirmed by recent experiment reports. Furthermore, HGIMDA could be effectively applied to new diseases and new miRNAs without any known associations, which overcome the important limitations of many previous computational models.

Differential expression of microRNAs in the normal skin of the Han and Uyghur populations in Xinjiang Province

In this study, we investigated the expression of microRNAs (miRNAs) in the skin samples from the Han and Uyghur populations in Xinjiang, China. The miRNA levels of the normal skin samples from 10 individuals of Uyghur or Han were tested by microarray and the expression differentiations were compared. Among the 3100 probes for microarray, a total of 247 miRNAs were differentially expressed in the Han versus Uyghur population, including 76 upregulated miRNAs and 171 downregulated miRNAs. The most significantly upregulated miRNAs were miR-141-3p, miR-1915-5p, kshv-miR-K12-2-5p, and miR-222-3p. And the most significantly downregulated miRNAs included miR-1207-3p and miR-625-3p. We have confirmed the upregulation of miR-141-3p and miR-1915-5p by qRT-PCR. There were no statistical correlations in the expression of miR-141-3p or miR-1915-5p with the age or gender within each group. Interestingly, the differentially expressed miRNAs were enriched in some cancer-related pathways, such as p53, mitogen-activated protein kinase, and WNT signal pathways. Collectively, these dysregulated expressions of the miRNAs may provide a better understanding of the differences in the incidence and mortality of skin-related carcinoma between the Uyghur and Han populations in Xinjiang.

NEAT1 upregulates EGCG-induced CTR1 to enhance cisplatin sensitivity in lung cancer cells

Platinum-based drugs are the firstline of treatment for non-small cell lung cancer (NSCLC), but resistance to these drugs is a major obstacle to effective chemotherapy. Our previous study revealed that the green tea polyphenol, EGCG, induced cisplatin transporter CTR1 (copper transporter 1) and enhanced cisplatin sensitivity in ovarian cancer. In this study, we found that EGCG upregulated CTR1 and increased platinum accumulation in NSCLC (A549, H460 and H1299) cells, cDDP-resistant A549 cells and a nude mouse xenograft model. Cisplatin-induced inhibition of cell growth was enhanced by EGCG treatment in vitro and in vivo. MicroRNA hsa-mir-98-5p appears to suppress CTR1 gene expression, while long non-coding RNA (lncRNA) nuclear enriched abundant transcript 1 (NEAT1) appears to enhance it. Bioinformatics analysis showed that hsa-mir-98-5p has specific complementary binding sites for NEAT1. In addition, hsa-mir-98-5p was predicted to be a putative CTR1 target. NEAT1 may act as a competing endogenous lncRNA to upregulate EGCG-induced CTR1 by sponging hsa-mir-98-5p in NSCLC. Our findings reveal a novel mechanism how NEAT1 upregulates EGCG-induced CTR1 and enhances cisplatin sensitivity in vitro and in vivo, and suggest EGCG could serve as an effective adjuvant chemotherapeutic in lung cancer treatment.

Circular RNA hsa_circ_0003221 (circPTK2) promotes the proliferation and migration of bladder cancer cells

Emerging studies have shown that circular RNAs could be ideal biomarkers and even potential therapeutic targets for some tumors, including bladder cancer. However, only a few studies have investigated the circular RNAs in human bladder cancer. The key circular RNA molecules are closely related to bladder cancer and their roles remain largely unknown. Here, we investigated a novel circular RNA molecule, hsa-circ-0003221(circPTK2), which is differentially expressed in bladder carcinoma. Significant differential expression levels of circPTK2 were confirmed with quantitative PCR in 40 pairs of tissue and blood samples from patients with bladder carcinoma. Moreover, circPTK2 levels both in tissue and blood were significantly correlated with several clinicopathologic characteristics, including poor differentiation (P = 0.0103 in tissue, P = 0.024 in blood), N2-N3 lymph node metastasis (P = 0.0065 in tissue, P = 0.016 in blood), and T(II-III-IV) stage (P = 0.008 in tissue, P = 0.0003 in blood). Quantitative PCR results confirmed that circPTK2 is highly expressed in migrated cells separated by Transwell assay and in metastatic lymph nodes of tumors transplanted in nude mice. In vitro silence of circPTK2 by small interfering RNA inhibited the proliferation and migration of bladder cancer cells. On the contrary, circPTK2 overexpression promoted proliferation and migration. This study showed that circPTK2 promotes proliferation and migration of cells and may be a novel potential biomarker and therapeutic target for bladder cancer diagnosis and therapy.

MiR-98 inhibits malignant progression via targeting MTDH in squamous cell carcinoma of the head and neck

PURPOSE

MicroRNAs function through regulating specific target mRNA expression and then participate in the development and progression of diverse human cancers. MiR-98 shows aberrant expression and dysfunction in tumors. However, its clinical significance and exact role in squamous cell carcinoma of the head and neck (SCCHN) remain elusive.

METHODS

MiR-98 expression was examined by qRT-PCR and correlated with clinicopathological variables and prognosis in SCCHN patients. Effects of miR-98 on epithelial-mesenchymal transition (EMT) and the malignant phenotypes of SCCHN were studied. Finally, the role of target gene metadherin (MTDH) in miR-98 mediated effects were assayed.

RESULTS

Our results demonstrated that miR-98, as an endogenous inhibitor of MTDH via directly binding to its 3'-untranslated region (UTR) region, decreased significantly in SCCHN tissues. Decreased miR-98 expression was negatively correlated with T classification, clinical stage, lymph node metastasis and a shorter survival status in SCCHN patients. Loss-of-function and gain-of-function analyses confirmed that miR-98 inhibited cell proliferation, migration and invasion of SCCHN cells in vitro. Moreover, miR-98 repression led to increased MTDH expression and induced EMT alteration. Importantly, ectopic expression of MTDH partially reversed the effects caused by miR-98 overexpression.

CONCLUSIONS

Our study identifies that miR-98 serves as a suppressor in SCCHN progression via targeting oncogene MTDH.

A deep ensemble model to predict miRNA-disease association

Cumulative evidence from biological experiments has confirmed that microRNAs (miRNAs) are related to many types of human diseases through different biological processes. It is anticipated that precise miRNA-disease association prediction could not only help infer potential disease-related miRNA but also boost human diagnosis and disease prevention. Considering the limitations of previous computational models, a more effective computational model needs to be implemented to predict miRNA-disease associations. In this work, we first constructed a human miRNA-miRNA similarity network utilizing miRNA-miRNA functional similarity data and heterogeneous miRNA Gaussian interaction profile kernel similarities based on the assumption that similar miRNAs with similar functions tend to be associated with similar diseases, and vice versa. Then, we constructed disease-disease similarity using disease semantic information and heterogeneous disease-related interaction data. We proposed a deep ensemble model called DeepMDA that extracts high-level features from similarity information using stacked autoencoders and then predicts miRNA-disease associations by adopting a 3-layer neural network. In addition to five-fold cross-validation, we also proposed another cross-validation method to evaluate the performance of the model. The results show that the proposed model is superior to previous methods with high robustness.