Current understanding of the functional roles of aberrantly expressed microRNAs in esophageal cancer

The role of microRNA-21 (miR-21) in pathogenesis, diagnosis, and prognosis of gastrointestinal cancers: A review

MicroRNAs (miRNAs) are small non-coding RNAs regulating the expression of several target genes. miRNAs play a significant role in cancer biology, as they can downregulate their corresponding target genes by impeding the translation of mRNA (at the mRNA level) as well as degrading mRNAs by binding to the 3'-untranslated (UTR) regions (at the protein level). miRNAs may be employed as cancer biomarkers. Therefore, miRNAs are widely investigated for early detection of cancers which can lead to improved survival rates and quality of life. This is particularly important in the case of gastrointestinal cancers, where early detection of the disease could substantially impact patients' survival. MicroRNA-21 (miR-21 or miRNA-21) is one of the most frequently researched miRNAs, where it is involved in the pathophysiology of cancer and the downregulation of several tumor suppressor genes. In gastrointestinal cancers, miR-21 regulates phosphatase and tensin homolog (PTEN), programmed cell death 4 (PDCD4), mothers against decapentaplegic homolog 7 (SMAD7), phosphatidylinositol 3-kinase /protein kinase B (PI3K/AKT), matrix metalloproteinases (MMPs), β-catenin, tropomyosin 1, maspin, and ras homolog gene family member B (RHOB). In this review, we investigate the functions of miR-21 in pathogenesis and its applications as a diagnostic and prognostic cancer biomarker in four different gastrointestinal cancers, including colorectal cancer (CRC), pancreatic cancer (PC), gastric cancer (GC), and esophageal cancer (EC).

Targeting Autophagy for Developing New Therapeutic Strategy in Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) is a prevalent cause of low back pain. IVDD is characterized by abnormal expression of extracellular matrix components such as collagen and aggrecan. In addition, it results in dysfunctional growth, senescence, and death of intervertebral cells. The biological pathways involved in the development and progression of IVDD are not fully understood. Therefore, a better understanding of the molecular mechanisms underlying IVDD could aid in the development of strategies for prevention and treatment. Autophagy is a cellular process that removes damaged proteins and dysfunctional organelles, and its dysfunction is linked to a variety of diseases, including IVDD and osteoarthritis. In this review, we describe recent research findings on the role of autophagy in IVDD pathogenesis and highlight autophagy-targeting molecules which can be exploited to treat IVDD. Many studies exhibit that autophagy protects against and postpones disc degeneration. Further research is needed to determine whether autophagy is required for cell integrity in intervertebral discs and to establish autophagy as a viable therapeutic target for IVDD.

The Use of miRNAs in Predicting Response to Neoadjuvant Therapy in Oesophageal Cancer

Oesophageal cancer (OC) is the ninth most common cancer worldwide. Patients receive neoadjuvant therapy (NAT) as standard of care, but less than 20% of patients with oesophageal adenocarcinoma (OAC) or a third of oesophageal squamous cell carcinoma (OSCC) patients, obtain a clinically meaningful response. Developing a method of determining a patient's response to NAT before treatment will allow rational treatment decisions to be made, thus improving patient outcome and quality of life. (1) Background: To determine the use and accuracy of microRNAs as biomarkers of response to NAT in patients with OAC or OSCC. (2) Methods: MEDLINE, EMBASE, Web of Science and the Cochrane library were searched to identify studies investigating microRNAs in treatment naïve biopsies to predict response to NAT in OC patients. (3) Results: A panel of 20 microRNAs were identified as predictors of good or poor response to NAT, from 15 studies. Specifically, miR-99b, miR-451 and miR-505 showed the strongest ability to predict response in OAC patients along with miR-193b in OSCC patients. (4) Conclusions: MicroRNAs are valuable biomarkers of response to NAT in OC. Research is needed to understand the effects different types of chemotherapy and chemoradiotherapy have on the predictive value of microRNAs; studies also require greater standardization in how response is defined.

Role of Annexin A1 in Squamous Cell Lung Cancer Progression

Lung cancer remains the primary cause of cancer-related death worldwide, and its molecular mechanisms of tumor progression need further characterization to improve the clinical management of affected patients. The role of Annexin A1 (ANXA1) in tumorigenesis and cancer progression in general and especially in lung cancer remains to be controversial and seems to be highly tissue specific and inconsistent among tumor initiation, progression, and metastasis. In the current study, we investigated ANXA1 expression in 81 squamous cell lung cancer (SQCLC), 86 pulmonary adenocarcinoma (AC), and 30 small cell lung cancer (SCLC) patient-derived tissue samples and its prognostic impact on patient's survival. Mechanistically, we analyzed the impact of ANXA1 expression on proliferation and migration of SQCLC cell lines using CRISPR-Cas9 and mammalian overexpression vectors. Strong expression of ANXA1 was significantly correlated to longer overall survival only in SQCLC patients (P = 0.019). Overexpression of ANXA1 promoted proliferation in SQCLC cell lines but suppressed their migration, while knockout of ANXA1 promoted cell migration and suppressed proliferation. In conclusion, ANXA1 expression might elongate patients' survival by inhibiting tumor cell migration and subsequent metastasis.

Panax ginseng C.A. Meyer (Rg3) Ameliorates Gastric Precancerous Lesions in Atp4a-/- Mice via Inhibition of Glycolysis through PI3K/AKT/miRNA-21 Pathway

Gastric cancer, one of the most common types of cancers, develops over a series of consecutive histopathological stages. As such, the analysis and research of the gastric precancerous lesions (GPLs) play an important role in preventing the occurrence of gastric cancer. Ginsenoside Rg3 (Rg3), an herbal medicine, plays an important role in the prevention and treatment of various cancers. Studies have demonstrated a correlation between glycolysis and gastric cancer progression. Herein, the aim of the present study was to clarify the potential role for glycolysis pathogenesis in Rg3-treated GPL in Atp4a^−/− mice. The GPL mice model showed chronic gastritis, intestinal metaplasia, and more atypical hyperplasia in gastric mucosa. According to the results of HE and AB-PAS staining, it could be confirmed that GPL mice were obviously reversed by Rg3. Additionally, the increased protein levels of PI3K, AKT, mTOR, HIF-1α, LDHA, and HK-II, which are crucial factors for evaluating GPL in the aspect of glycolysis pathogenesis in the model group, were downregulated by Rg3. Meanwhile, the miRNA-21 expression was decreased and upregulated by Rg3. Furthermore, the increased gene levels of Bcl-2 and caspase-3 were attenuated in Rg3-treated GPL mice. In conclusion, the findings of this study imply that abnormal glycolysis in GPL mice was relieved by Rg3 via regulation of the expressions of PI3K, AKT, mTOR, HIF-1α, LDHA, HK-II, and miRNA-21. Rg3 is an effective supplement for GPL treatment and can be harnessed to inhibit proliferation and induce apoptosis of GPL cells.

Up-Regulation of MicroRNA-21 Indicates Poor Prognosis and Promotes Cell Proliferation in Esophageal Squamous Cell Carcinoma via Upregulation of lncRNA SNHG1

Introduction

MicroRNA-21 (miRNA-21) and lncRNA SNHG1 (small nucleolar RNA host gene 1) are known to be aberrantly upregulated and promote tumor progression in various cancers. Nevertheless, very few studies have determined the roles of tissue and circulating miRNA-21 and SNHG1 in ESCC patients. Particularly, knowledge about the characteristics of miRNA-21 and SNHG1 expression and their correlations with survival rates, as well as their interaction with each other remains inadequate in ESCC.

Methods

Thse expression level of miRNA-21 and SNHG1 of tissues, serum and cell lines were detected by qRT-PCR, and the characteristics of their expression and clinicopathology were analyzed. Then, the diagnostic and prognosis value of serum and tissue miRNA-21 and SNHG1 were evaluated, respectively. In addition, the interaction with each other between miRNA-21 and SNHG1, as well as the effect on ESCC cell proliferation were further clarified.

Results

The expression level of miRNA-21 and SNHG1 are significantly upregulated in tissues, serum and cell lines of ESCC, and tissue miRNA-21 and SNHG1 significantly correlates with lymph node metastasis, TNM stage, tumor size, and poor overall survival in ESCC patients. The receiver operating characteristic (ROC) curves show that areas under the ROC curve (AUC) for serum miRNA-21 and SNHG1 are 0.928 and 0.850, respectively. Pearson correlation coefficient indicated that the expression levels of miRNA-21 and SNHG1 in frozen cancerous tissues are significantly associated with their respective serum levels. Further, Cox univariate and multivariate analyses reveal that miRNA-21 and SNHG1 are independent prognostic factors for overall survival (OS) and disease-free survival (DFS) in ESCC patients. In addition, our in vitro data revealed a novel regulatory pathway, in which miRNA-21 is probably a unidirectional upstream positive regulator of SNHG1 in ESCC cells, and the interaction between miRNA-21 and SNHG1 plays an important role in the proliferation of ESCC cells.

Discussion

In summary, our data show that SNHG1 may be a novel downstream target of miRNA-21 and not vice versa in ESCC cells and contributes significantly toward the proliferation of ESCC cells. These findings suggest that miRNA-21 and SNHG1 may serve as potential diagnostic, prognostic biomarkers and therapeutic targets for ESCC patients.

miR-760 exerts an antioncogenic effect in esophageal squamous cell carcinoma by negatively driving fat metabolism via targeting c-Myc

miR-760 is downregulated in various human tumors, and fat metabolism disorder correlates with tumor progression, especially anomalism of key fat metabolic enzymes that are positively modulated by c-Myc. The aim of our study is to elucidate the presumptive molecular mechanisms of miR-760-mediated esophageal squamous cell carcinoma (ESCC) cell function and to assess the therapeutic significance of miR-760 in ESCC patients. Quantitative real-time PCR (RT-qPCR) analysis indicated that miR-760 was significantly downexpressed in ESCC tissues and cell lines. Cell counting kit-8 (CCK-8) assay, colony formation assay, transwell assay, and flow cytometry denoted that induced ectopic overexpression of miR-760 dramatically inhibited ESCC cells proliferation, attenuated migration, and invasion facilitated apoptosis in vitro. Mechanistically, c-Myc predicted using bioinformatics was identified as a potential target gene of miR-760 by luciferase reporter assay. Furthermore, mRNA and protein expression levels of c-Myc and key fat metabolic enzymes were downregulated with miR-760 mimics. The above investigation results, responsible for the antineoplastic properties of miR-760 in ESCC, preliminarily highlighted that the hypothetical signal amongst miR-760, c-Myc, and key fat metabolic enzymes may develop a novel diagnostic marker, therapeutic target, and independent prognostic indicator.

Human salivary microRNAs in Cancer

Circulating microRNAs (miRNAs) have emerged as excellent candidates for cancer biomarkers. Several recent studies have highlighted the potential use of saliva for the identification of miRNAs as novel biomarkers, which represents a great opportunity to improve diagnosis and monitor general health and disease. This review summarises the mechanisms of miRNAs deregulation in cancer, the value of targeting them with a therapeutic intention and the evidence of the potential clinical use of miRNAs expressed in saliva for the detection of different cancer types. We also provide a comprehensive review of the different methods for normalising the levels of specific miRNAs present in saliva, as this is a critical step in their analysis, and the challenge to validate salivary miRNAs as a reality to manage cancer patients.

Determination of absolute expression profiles using multiplexed miRNA analysis

Accurate measurement of miRNA expression is critical to understanding their role in gene expression as well as their application as disease biomarkers. Correct identification of changes in miRNA expression rests on reliable normalization to account for biological and technological variance between samples. Ligo-miR is a multiplex assay designed to rapidly measure absolute miRNA copy numbers, thus reducing dependence on biological controls. It uses a simple 2-step ligation process to generate length coded products that can be quantified using a variety of DNA sizing methods. We demonstrate Ligo-miR's ability to quantify miRNA expression down to 20 copies per cell sensitivity, accurately discriminate between closely related miRNA, and reliably measure differential changes as small as 1.2-fold. Then, benchmarking studies were performed to show the high correlation between Ligo-miR, microarray, and TaqMan qRT-PCR. Finally, Ligo-miR was used to determine copy number profiles in a number of breast, esophageal, and pancreatic cell lines and to demonstrate the utility of copy number analysis for providing layered insight into expression profile changes.

Differential role of microRNAs in the pathogenesis and treatment of Esophageal cancer

Esophageal cancer (EC) is the most invasive disease associated with inclusive poor prognosis. EC usually is found as either adenocarcinoma (EAC) or squamous cell carcinomas (ESCC). ESCC forms in squamous cells and highly occurs in the upper third of the esophagus. EAC appears in glandular cells and ordinarily develops in the lower one third of the esophagus near the stomach. Barrett's esophagus (BE) is a metaplastic precursor of EAC. There is a persistent need for improving our understanding of the molecular basis of this disease. MicroRNAs (miRNAs) demonstrate an uncovered class of small, non-coding RNAs that can negatively regulate the protein coding gene, and are associated with approximately all known physiological and pathological processes, especially cancer. MiRNAs can affect cancer pathogenesis, playing a crucial role as either oncogenes or tumor suppressors. The recent emergence of observations on the role of miRNAs in cancer and their functions has induced many investigations to examine their relevance to esophageal cancer. In esophageal cancer, miRNA dysregulation plays a crucial role in cancer prognosis and in patients' responsiveness to neo-adjuvant and adjuvant therapies. In this review, the oncogenic, tumor suppressive, and drug resistance related roles of miRNAs, and their involvement in the pathogenesis and treatment of esophageal cancer were summarized.

MicroRNA-200b suppresses cell invasion and metastasis by inhibiting the epithelial-mesenchymal transition in cervical carcinoma

The expression of microRNA (miR)-200b is suppressed in numerous tumor types, leading to epithelial-mesenchymal transition, which enables solid tissue epithelial cancers to invade and metastasize. The present study assessed the role of miR-200b in cervical cancer with the aim of clarifying the underlying pathophysiological mechanisms and to identify potential strategies for its prevention and treatment of cervical cancer. Reverse‑transcription quantitative PCR revealed that miR‑200b was downregulated in invasive cervical carcinoma tissues compared with that in normal adjacent tissues. A Transwell migration assay indicated that transfection of cervical cancer cells with miR‑200b mimics significantly inhibited their migratory potential, while migration was enhanced in cells transfected with miR‑200b inhibitor. Furthermore, western blot analysis indicated a negative correlation between miR‑200b and mesenchymal marker vimentin as well as matrix metalloproteinase‑9, which has a key role in tumor invasion and metastasis. In addition, a positive correlation between miR‑200b and the epithelial marker E‑cadherin was revealed by western blot and immunofluorescence. The results of the present study suggested that miR‑200b suppressed the migratory potential of cervical carcinoma cells and therefore their ability to metastasize by inhibiting the epithelial-mesenchymal transition, which may be utilized for the treatment of cervical cancer.