miR-20a enhances cisplatin resistance of human gastric cancer cell line by targeting NFKBIB. Tumour Biol. 2016;37:1261-1269. [PMID: 26286834 DOI: 10.1007/s13277-015-3921-1]

Aryl Hydrocarbon Receptor-Dependent miRNA-382-5p Mediates the Classical Pyroptosis Induced by Foodborne Benzo(a)pyrene through Targeting IκB in Liver

Benzo(a)pyrene (BaP), a carcinogen prevalent in high-temperature processed foods, activates the aryl hydrocarbon receptor (AhR) and induces liver pyroptotic injury. MicroRNAs regulate mRNA expression and are involved in BaP toxicity. In this study, we investigated the essential role of microRNA in BaP-induced pyroptosis. In vivo, BaP induces liver pyroptotic injury by activating AhR, which may be attributed to AhR's influence on microRNA expression. The miRNA-382-5p/Akt and miRNA-382-5p/IκB pairs were predicted to post-transcriptionally regulate pyroptosis. In vitro, miRNA-382-5p activates the classical NF-κB/NLRP3/Caspase-1 pyroptosis signaling pathway by targeting and inhibiting the IκB gene. Furthermore, AhR activation by BaP could promote the high expression of miRNA-382-5p, thereby upregulating the NF-κB/NLRP3/Caspase-1 pyroptosis signaling pathway. In summary, we established that the AhR-mediated miR-382-5p/NF-κB/NLRP3/Caspase-1 axis is a key driver of BaP-induced pyroptosis in hepatocytes and elucidated the underlying mechanisms. These findings provide a valuable theoretical basis for considering miRNA-382-5p as a potential target for preventing BaP toxicity.

Circulating non-coding RNAs as a tool for liquid biopsy in solid tumors

Solid tumors are significant causes of global mortality and morbidity. Recent research has primarily concentrated on finding pathology-specific molecules that can be acquired non-invasively and that can change as the disease progresses or in response to treatment. The focus of research has moved to RNA molecules that are either freely circulating in body fluids or bundled in microvesicles and exosomes because of their great stability in challenging environments, ease of accessibility, and changes in level in response to therapy. In this context, there are many non-coding RNAs that can be used for this purpose in liquid biopsies. Out of these, microRNAs have been extensively studied. However, there has been an increase of interest in studying long non-coding RNAs, piwi interacting RNAs, circular RNAs, and other small non-coding RNAs. In this article, an overview of the most researched circulating non-coding RNAs in solid tumors will be reviewed, along with a discussion of the significance of these molecules for early diagnosis, prognosis, and therapeutic targets. The publications analyzed were extracted from the PubMed database between 2008 and June 2024.

Dysregulation of miR-122, miR-574 and miR-375 in Egyptian patients with breast cancer

BACKGROUND

The early detection of breast cancer (BC) is receiving global attention, creating an urgent need for more sensitive and comprehensive strategies for preventive intervention, therapy assessment, and prognosis prediction. Aberrant expression of miRNAs has been observed in various malignancies and may be potential targets for therapy. Our study aims to examine the expression profiles of miR-375, miR-574-3p, and miR-122 in the sera of Egyptian women with BC, benign breast lesions, and a control group. We hope to determine if these miRNAs can serve as minimally invasive biomarkers for BC.

METHODS

This is a case-control study in which 77 patients with newly diagnosed BC, 20 patients with benign breast tumors, and 30 normal healthy subjects as controls were recruited from the outpatient clinic of the National Cancer Institute. The assessment of miRNAs was conducted using RT-PCR (Applied Biosystems).

RESULTS

The expression level of miRNA-122 was significantly upregulated in the BC group, while the expression levels of miRNA-574 and miRNA-375 showed significant downregulation in BC patients. Serum miR-122 and miRNA-375 were able to distinguish breast cancer from the benign and control groups in ROC curve analysis, with AUCs of 0.786 and 0.796, respectively. Our results also showed that serum miR-122 and miR-574 are significant predictor variables in the multivariate analysis, after adjusting for age.

CONCLUSIONS

Our findings suggest that miR-122 may act as an onco-microRNA, while miR-574 and miR-375 may have a main tumour suppressor role. The studied miRNAs may serve as minimally invasive biomarkers for cases of breast cancer and as promising potential therapeutic targets for breast cancer.

Advances in prognostic models for osteosarcoma risk

The risk prognosis model is a statistical model that uses a set of features to predict whether an individual will develop a specific disease or clinical outcome. It can be used in clinical practice to stratify disease severity and assess risk or prognosis. With the advancement of large-scale second-generation sequencing technology, along Prognosis models for osteosarcoma are increasingly being developed as large-scale second-generation sequencing technology advances and clinical and biological data becomes more abundant. This expansion greatly increases the number of prognostic models and candidate genes suitable for clinical use. This article will present the predictive effects and reliability of various prognosis models, serving as a reference for their evaluation and application.

Prognostic value of plasma microRNAs for non-small cell lung cancer based on data mining models

BACKGROUND

As biomarkers, microRNAs (miRNAs) are closely associated with the occurrence, progression, and prognosis of non-small cell lung cancer (NSCLC). However, the prognostic predictive value of miRNAs in NSCLC has rarely been explored. In this study, the value in prognosis prediction of NSCLC was mined based on data mining models using clinical data and plasma miRNAs biomarkers.

METHODS

A total of 69 patients were included in this prospective cohort study. After informed consent, they filled out questionnaires and had their peripheral blood collected. The expressions of plasma miRNAs were examined by quantitative polymerase chain reaction (qPCR). The Whitney U test was used to analyze non-normally distributed data. Kaplan-Meier was used to plot the survival curve, the log-rank test was used to compare with the overall survival curve, and the Cox proportional hazards model was used to screen the factors related to the prognosis of lung cancer. Data mining techniques were utilized to predict the prognostic status of patients.

RESULTS

We identified that smoking (HR = 2.406, 95% CI = 1.256-4.611), clinical stage III + IV (HR = 5.389, 95% CI = 2.290-12.684), the high expression group of miR-20a (HR = 4.420, 95% CI = 1.760-11.100), the high expression group of miR-197 (HR = 3.828, 95% CI = 1.778-8.245), the low expression group of miR-145 ( HR = 0.286, 95% CI = 0.116-0.709), and the low expression group of miR-30a (HR = 0.307, 95% CI = 0.133-0.706) was associated with worse prognosis. Among the five data mining models, the decision trees (DT) C5.0 model performs the best, with accuracy and Area Under Curve (AUC) of 93.75% and 0.929 (0.685, 0.997), respectively.

CONCLUSION

The results showed that the high expression level of miR-20a and miR-197, the low expression level of miR-145 and miR-30a were strongly associated with poorer prognosis in NSCLC patients, and the DT C5.0 model may serve as a novel, accurate, method for predicting prognosis of NSCLC.

Mechanism of cisplatin resistance in gastric cancer and associated microRNAs

Gastric cancer (GC) is a common malignant tumor with high morbidity and mortality rates that seriously affects human health worldwide. Although surgery is currently the preferred clinical treatment for GC, chemotherapy remains the first choice for perioperative treatment, adjuvant therapy, and palliative care for patients with advanced GC. Cisplatin (DDP) is an antineoplastic agent that has been used clinically for decades, and it is the first-line chemotherapy for many solid tumors. However, the therapeutic efficacy of DDP is often limited by resistance and the complexity of its resistance mechanisms, which involve multiple proteins and signaling pathways. It is well documented that a variety of microRNAs (miRNAs) differentially expressed in DDP-resistant GC cells play important roles in regulating or reversing DDP resistance via various pathways. In this review, we first provide an introduction to the cytotoxicity and major resistance mechanisms of DDP in GC and then discuss the role and mechanism of miRNAs in regulating the DDP resistance process in GC cells. This work demonstrates the potential of relevant miRNAs to become diagnostic and prognostic biomarkers for gastric cancer and targets of action to enhance chemosensitivity and provides directions for future research.

Search for New Participants in the Pathogenesis of High-Grade Serous Ovarian Cancer with the Potential to Be Used as Diagnostic Molecules

Recent studies have attempted to develop molecular signatures of epithelial ovarian cancer (EOC) based on the quantitation of protein-coding and non-coding RNAs to predict disease prognosis. Due to the heterogeneity of EOC, none of the developed prognostic signatures were directly applied in clinical practice. Our work focuses on high-grade serous ovarian carcinoma (HGSOC) due to the highest mortality rate relative to other types of EOC. Using deep sequencing of small non-coding RNAs in combination with quantitative real-time PCR, we confirm the dualistic classification of epithelial ovarian cancers based on the miRNA signature of HGSOC (type 2), which differs from benign cystadenoma and borderline cystadenoma-precursors of low-grade serous ovarian carcinoma (type 1)-and identified two subtypes of HGSOC, which significantly differ in the level of expression of the progesterone receptor in the tumor tissue, the secretion of miR-16-5p, miR-17-5p, miR-93-5p, miR-20a-5p, the level of serum CA125, tumor size, surgical outcome (optimal or suboptimal cytoreduction), and response to chemotherapy. It was found that the combined determination of the level of miR-16-5p, miR-17-5p, miR-20a-5p, and miR-93-5p circulating in blood plasma of patients with primary HGSOC tumors makes it possible to predict optimal cytoreduction with 80.1% sensitivity and 70% specificity (p = 0.022, TPR = 0.8, FPR = 0.3), as well as complete response to adjuvant chemotherapy with 77.8% sensitivity and 90.9% specificity (p = 0.001, TPR = 0.78, FPR = 0.09). After the additional verification of the obtained data in a larger HGSOC patient cohort, the combined quantification of these four miRNAs is proposed to be used as a criterion for selecting patients either for primary cytoreduction or neoadjuvant chemotherapy followed by interval cytoreduction.

Dysregulation of Survivin-Targeting microRNAs in Autoimmune Diseases: New Perspectives for Novel Therapies

It has been well established that the etiopathogenesis of diverse autoimmune diseases is rooted in the autoreactive immune cells' excessively proliferative state and impaired apoptotic machinery. Survivin is an anti-apoptotic and mitotic factor that has sparked a considerable research interest in this field. Survivin overexpression has been shown to contribute significantly to the development of autoimmune diseases via autoreactive immune cell overproliferation and apoptotic dysregulation. Several microRNAs (miRNAs/miRs) have been discovered to be involved in survivin regulation, rendering the survivin-miRNA axis a perspective target for autoimmune disease therapy. In this review, we discuss the role of survivin as an immune regulator and a highly implicated protein in the pathogenesis of autoimmune diseases, the significance of survivin-targeting miRNAs in autoimmunity, and the feasibility of targeting the survivin-miRNA axis as a promising therapeutic option for autoimmune diseases.

MeCP2 Increases Cisplatin Resistance in Human Gastric Cancer through the Activation of the AKT Pathway by Facilitating PDK-1 Transcription

BACKGROUND

Increasing evidence indicates that an imbalance of oncogenes is implicated in chemotherapy resistance in cancers. Methyl-CpG binding protein 2 (MeCP2), which acts as a master epigenetic regulator of various gene expressions, is involved in the carcinogenesis and progression of gastric cancer. However, whether this vital role may participates in acquired cisplatin resistance in GC remains unknown.

OBJECTIVE

This study aimed to determine whether inhibition of MeCP2 expression could sensitize DDP-resistant GC cells to DDP and to elucidate its underlying molecular mechanism.

METHODS

qRT-PCR and western blotting were used to evaluate MeCP2 expression in GC DDP-resistant GC cells. Subsequently, cell viability, colony formation, cell cycle, cell apoptosis and tumorigenicity assays were performed to explore the role of MeCP2 in vitro and in vivo. Chromatin immunoprecipitation-qPCR and luciferase reporter assays were used to identify whether 3-phosphoinositide-dependent protein kinase 1 (PDK-1) is a direct target gene of MeCP2.

RESULTS

MeCP2 was upregulated in malignant DDP-resistant cells compared to that in non-DDP-resistant GC cells or normal gastric epithelial cells. MeCP2 knockdown increased the sensitivity of DDP-resistant GC cells to DDP, resulting in reduced cell growth, G0/G1 phase arrest and increased apoptosis, wheras MeCP2 overexpression attenuated DDP sensitivity of DDP-resistant GC cells. In addition, MeCP2 knockdown enhanced DDP sensitivity in tumors in vivo. MeCP2 elevated PDK-1 expression by binding to its CpG sites in promoter regions, and inhibition of PDK-1 reversed the inductive effect of MeCP2 overexpression on DDP resistance in GC cells.

CONCLUSION

These findings indicate that silencing MeCP2 may potentiate DDP induced cell death, providing a promising therapeutic strategy for GC.

Mechanisms of Action And Clinical Implications of MicroRNAs in the Drug Resistance of Gastric Cancer

Gastric cancer (GC) is one of the most common malignant tumors of digestive systems worldwide, with high recurrence and mortality. Chemotherapy is still the standard treatment option for GC and can effectively improve the survival and life quality of GC patients. However, with the emergence of drug resistance, the clinical application of chemotherapeutic agents has been seriously restricted in GC patients. Although the mechanisms of drug resistance have been broadly investigated, they are still largely unknown. MicroRNAs (miRNAs) are a large group of small non-coding RNAs (ncRNAs) widely involved in the occurrence and progression of many cancer types, including GC. An increasing amount of evidence suggests that miRNAs may play crucial roles in the development of drug resistance by regulating some drug resistance-related proteins as well as gene expression. Some also exhibit great potential as novel biomarkers for predicting drug response to chemotherapy and therapeutic targets for GC patients. In this review, we systematically summarize recent advances in miRNAs and focus on their molecular mechanisms in the development of drug resistance in GC progression. We also highlight the potential of drug resistance-related miRNAs as biomarkers and therapeutic targets for GC patients.

LncRNA HLA Complex Group 11 Knockdown Alleviates Cisplatin Resistance in Gastric Cancer by Targeting the miR-144-3p/UBE2D1 Axis

OBJECTIVE

Cisplatin (DDP) treatment is one of the most predominant chemotherapeutic strategies for patients with gastric cancer (GC). LncRNA noncoding RNA HLA complex group 11 (lncRNA HCG11) has been confirmed to promote GC progression. This study attempted to investigate the underlying molecular mechanism of HCG11 in DDP resistance of GC.

METHODS

qRT-PCR was performed to evaluate the expression of HCG11, microRNA-144-3p (miR-144-3p), and ubiquitin-conjugating enzyme E2 D1 (UBE2D1) in GC. The correlation between HCG11 and clinicopathological features of GC patients was assessed. DDP-resistant GC cells and their parental cells were cultured in different concentrations of DDP. The role of HCG11 for the viability and the half maximal inhibitory concentration (IC50) of DDP in DDP-resistant GC cells was determined by MTT assay. Then, the invasion of DDP-resistant GC cells was measured by transwell assay. Next, a dual-luciferase reporter assay was used to confirm the interactions among HCG11, miR-144-3p, and UBE2D1 in GC.

RESULTS

The expression of HCG11 and UBE2D1 was elevated in tumor tissues of GC patients, but miR-144-3p was declined. HCG11 expression was elevated in DDP-resistant GC patients and is strongly correlated with DDP sensitivity and World Health Organization grade in GC patients. HCG11 knockdown reduced the viability, IC50 of DDP, and invasion of DDP-resistant GC cells. Additionally, HCG11 targeted miR-144-3p and miR-144-3p further targeted UBE2D1. Feedback experiments indicated that low expression of miR-144-3p or overexpression of UBE2D1 mitigated the inhibitory effect of HCG11 depletion on DDP resistance of GC cells.

CONCLUSION

HCG11 knockdown attenuated DDP resistance of GC cells through via miR-144-3p/UBE2D1 axis, affording a novel therapeutic strategy for GC.

MicroRNAs as the critical regulators of cisplatin resistance in gastric tumor cells

Combined chemotherapeutic treatment is the method of choice for advanced and metastatic gastric tumors. However, resistance to chemotherapeutic agents is one of the main challenges for the efficient gastric cancer (GC) treatment. Cisplatin (CDDP) is used as an important regimen of chemotherapy for GC which induces cytotoxicity by interfering with DNA replication in cancer cells and inducing their apoptosis. Majority of patients experience cisplatin-resistance which is correlated with tumor metastasis and relapse. Moreover, prolonged and high-dose cisplatin administrations cause serious side effects such as nephrotoxicity, ototoxicity, and anemia. Since, there is a high rate of recurrence after CDDP treatment in GC patients; it is required to clarify the molecular mechanisms associated with CDDP resistance to introduce novel therapeutic methods. There are various cell and molecular processes associated with multidrug resistance (MDR) including drug efflux, detoxification, DNA repair ability, apoptosis alteration, signaling pathways, and epithelial-mesenchymal transition (EMT). MicroRNAs are a class of endogenous non-coding RNAs involved in chemo resistance of GC cells through regulation of all of the MDR mechanisms. In present review we have summarized all of the miRNAs associated with cisplatin resistance based on their target genes and molecular mechanisms in gastric tumor cells. This review paves the way of introducing a miRNA-based panel of prognostic markers to improve the efficacy of chemotherapy and clinical outcomes in GC patients. It was observed that miRNAs are mainly involved in cisplatin response of gastric tumor cells via regulation of signaling pathways, autophagy, and apoptosis.

LncRNAs and miRNAs participate in determination of sensitivity of cancer cells to cisplatin

Cisplatin is an extensively used chemotherapeutic substance for various types of human malignancies including sarcomas, carcinomas and lymphomas. Yet, the vast application of this drug is hampered by the emergence of chemoresistance in some treated patients. Several mechanisms such as degradation of the membrane transporters by cisplatin have been implicated in the pathogenesis of this event. Recent researches have also indicated the role of long non-coding RNAs (lncRNAs) as well as micoRNAs (miRNAs) in the emergence of resistance to cisplatin in several cancer types. For instance, up-regulation of miR-21 has been associated with resistance to this agent in ovarian cancer, oral squamous cell cancer, gastric malignancy and non-small cell lung cancer (NSCLC). On the other hand, down-regulation of miR-218 has been implicated in emergence of chemoresistance in breast cancer and esophageal squamous cell carcinoma. MALAT1 is implicated in the chemoresistance of bladder cancer cells, NSCLC, gastric cancer and cervical cancer. Most notably, the expression profile of resistance-associated miRNAs and lncRNAs can predict overall survival of cancer patients. Mechanistic assays have revealed that interference with expression of some miRNAs and lncRNAs can reverse the resistance phenotype in cancer cells. In this paper, we review the scientific writings on the role of lncRNAs and miRNAs in the evolution of chemoresistance to cisplatin in cancer cells.

Non-coding RNAs underlying chemoresistance in gastric cancer

BACKGROUND

Gastric cancer (GC) is a major health issue in the Western world. Current clinical imperatives for this disease include the identification of more effective biomarkers to detect GC at early stages and enhance the prevention and treatment of metastatic and chemoresistant GC. The advent of non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs) and long-non coding RNAs (lncRNAs), has led to a better understanding of the mechanisms by which GC cells acquire features of therapy resistance. ncRNAs play critical roles in normal physiology, but their dysregulation has been detected in a variety of cancers, including GC. A subset of ncRNAs is GC-specific, implying their potential application as biomarkers and/or therapeutic targets. Hence, evaluating the specific functions of ncRNAs will help to expand novel treatment options for GC.

CONCLUSIONS

In this review, we summarize some of the well-known ncRNAs that play a role in the development and progression of GC. We also review the application of such ncRNAs in clinical diagnostics and trials as potential biomarkers. Obviously, a deeper understanding of the biology and function of ncRNAs underlying chemoresistance can broaden horizons toward the development of personalized therapy against GC.

Salvianolic acid B suppresses EMT and apoptosis to lessen drug resistance through AKT/mTOR in gastric cancer cells

The drug resistance of tumor cells greatly reduces the efficacy of chemotherapy drugs in gastric cancer. Salvianolic acid B (Sal-B) is considered as a chemopreventive agent which suppresses oxidative stress and apoptosis. Therefore, the study aims to clarify the mechanism of Sal-B in drug-resistant gastric cancer cells. CCK8 assay analyzed cell viabilities after GES1, AGS and AGS/DDP cells were respectively treated by Sal-B of different concentration or after AGS/DDP cells were disposed by cisplatin (DDP) in different concentration. The colony formation, ROS generation, apoptosis, migration, invasion and EMT marker proteins were respectively analyzed through formation assay, ROS kits, TUNNEL staining, Wound healing, Transwell assays and Western blot. The results demonstrated that Sal-B acted alone or in synergy with DDP to reduce cell viabilities, initiate ROS generation, promote cell apoptosis, as well as decrease migration, invasion and EMT in AGS and AGS/DDP cells. AKT activator and mTOR activator significantly reversed the above effects of Sal-B. Collectively, Sal-B regulated proliferation, EMT and apoptosis to reduce the resistance to DDP via AKT/mTOR pathway in DDP-resistant gastric cancer cells. Sal-B could be a potential anti-drug resistance agent to chemotherapy in gastric cancer.

Function and mechanisms of microRNA-20a in colorectal cancer

Colorectal cancer (CRC) is the third most common malignancy and the second leading cause of cancer-associated mortality worldwide. CRC currently has no specific biomarkers to promote its diagnosis and treatment and the underlying mechanisms regulating its pathogenesis have not yet been determined. MicroRNAs (miRs) are small, non-coding RNAs that exhibit regulatory functions and have been demonstrated to serve a crucial role in the post-transcriptional regulatory processes of gene expression that is associated with cell physiology and disease progression. Recently, abnormal miR-20a expression has been identified in a number of cancers types and this has become a novel focus within cancer research. High levels of miR-20a expression have been identified in CRC tissues, serum and plasma. In a recent study, miR-20a was indicated to be present in feces and to exhibit a high sensitivity to CRC. Therefore, miR-20a may be used as a marker for CRC and an indicator that can prevent the invasive examination of patients with this disease. Changes in the expression of miR-20a during chemotherapy can be used as a biomarker for monitoring resistance to treatment. In conclusion, miR-20a exhibits the potential for clinical application as a novel diagnostic biomarker and therapeutic target for use in patients with CRC. The present study focused on the role and mechanisms of miR-20a in CRC.

Non-coding RNA in drug resistance of gastric cancer

Gastric cancer (GC) is the third leading cause of cancer-related mortality worldwide. The poorly prognosis and survival of GC are due to diagnose in an advanced, non-curable stage and with a limited response to chemotherapy. The acquisition of drug resistance accounts for the majority of therapy failure of chemotherapy in GC patients. Although the mechanisms of anticancer drug resistance have been broadly studied, the regulation of these mechanisms has not been completely understood. Accumulating evidence has recently highlighted the role of non-coding RNAs (ncRNAs), including long non-coding RNAs and microRNAs, in the development and maintenance of drug resistance due to their regulatory features in specific genes involved in the chemoresistant phenotype of GC. We review the literature on ncRNAs in drug resistance of GC. This review summarizes the current knowledge about the ncRNAs’ characteristics, their regulation of the genes involved in chemoresistance and their potential as targeted therapies for personalized treatment in resistant GC.

Nuclear KIT induces a NFKBIB-RELA-KIT autoregulatory loop in imatinib-resistant gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are frequently driven by auto-activated, mutant KIT and have durable response to KIT tyrosine kinase inhibitor. However, acquired resistance is an increasing clinical issue in GIST patients receiving front-line imatinib therapy. Our previous studies showed the colocalization of KIT with DAPI-stained nuclei in GIST cells without knowing the role of nuclear KIT in GIST tumorigenesis. In this article, we first identified the binding of nuclear KIT to the promoter of NFKB inhibitor beta (NFKBIB) by chromatin immunoprecipitation (ChIP) sequencing and ChIP assays, which was accompanied with enhanced NFKBIB protein expression in GIST cells. Clinically, high NCCN risk GISTs had significantly higher mean expression levels of nuclear phospho-KIT and NFKBIB as compared with those of intermediate or low/very low-risk GISTs. Conversely, downregulation of NFKBIB by siRNA led to RELA nuclear translocation that could bind to the KIT promoter region and subsequently reduced KIT transcription/expression and the viability of GIST cells. These findings were further confirmed by either RELA overexpression or NFKB/RELA inducer, valproic acid, treatment to result in reduced KIT expression and relative cell viability of imatinib-resistant GIST cells. Combining valproic acid with imatinib showed significantly better growth inhibitory effects on imatinib-resistant GIST48 and GIST430 cells in vitro, and in the GIST430 animal xenograft model. Taken together, these results demonstrate the existence of a nuclear KIT-driven NFKBIB-RELA-KIT autoregulatory loop in GIST tumorigenesis, which are potential targets for developing combination therapy to overcome imatinib-resistant of KIT-expressing GISTs.

Induction/reversal of drug resistance in gastric cancer by non-coding RNAs (Review)

Gastric cancer (GC) is one of the most prevalent and malignant types of cancer worldwide. In China, it is the second most common type of cancer and the malignancy with the highest incidence and mortality rate. Chemotherapy for GC is not always effective due to the development of drug resistance. Drug resistance, which is frequently observed in GC, undermines the success rate of chemotherapy and the survival of patients with GC. The dysregulation of non‑coding RNAs (ncRNAs), primarily microRNAs (miRNAs or miRs) and long non‑coding RNAs (lncRNAs), is involved in the development of GC drug resistance via numerous mechanisms. These mechanisms contribute to the involvement of a large and complex network of ncRNAs in drug resistance. In this review, we focus on and summarize the latest research on the specific mechanisms of action of miRNAs and lncRNAs that modulate drug resistance in GC. In addition, we discuss future prospects and clinical applications of ncRNAs as potential targeted therapies against the chemoresistance of GC.

MiR-20a, a novel promising biomarker to predict prognosis in human cancer: a meta-analysis

Background

Recently, microRNA-20a (miR-20a) has been reported to influence the clinical features and may have prognostic value in human cancers. The present meta-analysis assessed the prognostic role of miR-20a in various carcinomas.

Methods

Literature searches of seven electronic databases were performed for eligible articles of the prognostic role of miR-20a in human cancers. Hazard ratios (HR) for overall survival (OS), disease free survival (DFS), progression-free survival (PFS) as well as their 95% confidence intervals (95%CIs) were used to assess the influence of miR-20a expression on patient prognosis. Odds ratio (OR) and 95%CIs were applied to evaluate the correlation between miR-20a expression and clinicopathological characteristics.

Results

Based on the OS analyzed by log rank tests, there was a significant association between miR-20a levels and OS by fixed effects model. By subgroup analyses, the significance was also observed in the studies of specimen derived from blood and gastrointestinal cancer group. The independent prognostic role of miR-20a expression for the OS was observed significantly by fixed effects model. In addition, we observed significant association between miR-20a expression levels and DFS of log rank tests, DFS of cox regression. Significant relation of gender/differentiation and the expression level of miR-20a was identified.

Conclusions

Base on the findings, the elevated miR-20a expression level is related to poor prognosis of gastrointestinal cancer patients. As for other types of carcinomas, the results are still not stable and more studies are required to further identify miR-20a prognostic values. In addition, miR-20a expression level is relatively higher in women than that in men, and increased miR-20a expression level is linked to poor tumor differentiation.

Change of Circulating and Tissue-Based miR-20a in Human Cancers and Associated Prognostic Implication: A Systematic Review and Meta-Analysis

Background

Previous literatures have investigated the change of miR-20a expression level in the progression of multiple cancers and its influence on patients' survival outcome, but results of now-available evidence are inconsistent.

Objective

To elucidate the prognostic value of circulating and tissue-based miR-20a for patients with various cancers.

Methods

A systematic search and review of eligible publications were carried out in three electronic databases including the Cochrane Library, PubMed, and Embase, and the methodological quality of included studies was assessed according to Newcastle-Ottawa Scale (NOS). Hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) for overall survival (OS), recurrence-free survival (RFS), disease-free survival (DFS), and progressive-free survival (PFS) of each study were pooled using a random effect model.

Results

In total, 24 studies involving 4186 samples of multiple cancers published in 20 articles were included in the statistical analysis. As for circulating miR-20a, five kinds of cancers containing gastric cancer, lymphoma, glioblastoma, prostate cancer, and non-small-cell lung cancer reported upregulated level in patients compared with normal healthy control, and overexpressed circulating miR-20a could confer an unfavorable factor for OS (HR = 1.71, 95% CIs: 1.43 -2.04, p < 0.01) and DFS (HR = 1.90, 95% CIs: 1.45-2.49, p < 0.01). As for tissue-based samples, 6 kinds of malignancies including colorectal cancer, salivary adenoid cystic carcinoma, gallbladder carcinoma, colon cancer, gastrointestinal cancer, and alveolar rhabdomyosarcoma revealed upregulated miR-20a expression level compared with paired nontumorous tissue, of which high expression of miR-20a was significantly associated with poor OS (HR = 2.74, 95% CIs: 1.38-5.42, p < 0.01) and DFS (HR = 2.68, 95% CIs: 1.32-5.45, p < 0.01); meanwhile, other 5 tumors containing breast cancer, cutaneous squamous cell carcinoma, hepatocellular carcinoma, oral squamous cell carcinoma, and epithelial ovarian cancer demonstrated downregulated miR-20a expression level compared with benign tissue, of which low miR-20a expression was significantly related to shorter OS (HR = 3.48, 95% CIs: 2.00-6.06, p < 0.01) and PFS/RFS (HR = 4.05, 95% CIs: 2.89-5.66, p < 0.01).

Conclusion

Change of circulating and tissue-based miR-20a expression possesses vital prognostic implication for human cancers. Augmented expression of circulating miR-20a predicts poor survival outcome for patients with cancers. Tissue-based miR-20a level may be upregulated or downregulated depending on cancer types; in the former condition, high expression of tissue miR-20a is a risk factor for unfavorable prognosis and in the latter condition low expression of tissue miR-20a is associated with shorter survival.

Increased expression of microRNAs, miR-20a and miR-326 in PBMCs of patients with type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disorder which is characterized by autoimmune attack on β cells of pancreas and lack of insulin. The involvement of microRNAs (miRNAs) in the development of immune system and their differential expression in various autoimmune diseases including T1D have been well established. In this study, the association between expression levels of miR-20a, miR-326 and T1D were evaluated. The expression levels of miR-20a and miR-326 were measured in the PBMCs of 21 T1D patients and 16 healthy controls using qPCR method. In silico analysis was also performed on targetome of miR-20a and miR-326. Both miR-20a (p value: 0.015) and miR-326 (p value: 0.005) were upregulated in the PBMCs of T1D patients compared to healthy controls. Furthermore, different dysregulated miR326-mRNA and miR20a-mRNA interactions were also suggested using integrative computational analysis. The expression level of miR-20a and miR-326 indicates significant association with T1D which suggests the possible regulatory effects of these non-coding RNAs in T1D.

MicroRNAs as non-invasive diagnostic biomarkers for gastric cancer: Current insights and future perspectives

Non-invasive diagnostic biomarkers may contribute to an early identification of gastric cancer (GC) and improve the clinical management. Unfortunately, no sensitive and specific screening biomarkers are available yet and the currently available approaches are limited by the nature of the disease. GC is a heterogenic disease with various distinct genetic and epigenetic events that occur during the multifactorial cascade of carcinogenesis. MicroRNAs (miRNAs) are commonly deregulated in gastric mucosa during the Helicobacter pylori infection and in stepwise manner from chronic gastritis, through preneoplastic conditions such as atrophic gastritis and intestinal metaplasia, to early dysplasia and invasive cancer. Identification of miRNAs in blood in 2008 led to a great interest on miRNA-based diagnostic, prognostic biomarkers in GC. In this review, we provide the most recent systematic review on the existing studies related to miRNAs as diagnostic biomarkers for GC. Here, we systematically evaluate 75 studies related to differential expression of circulating miRNAs in GC patients and provide novel view on various heterogenic aspects of the existing data and summarize the methodological differences. Finally, we highlight several important aspects crucial to improve the future translational and clinical research in the field.

Upregulation of miR-375 inhibits human liver cancer cell growth by modulating cell proliferation and apoptosis via targeting ErbB2

microRNAs (miRNA/miRs) are a class of small non-coding RNAs; they serve important biological roles in tumorigenesis through the regulation of oncogene expression, and they may be used for the diagnosis and treatment of human cancer. miR-375 was identified to exhibit abnormal expression levels in a number of types of tumor; however, the biological role of miR-375 in human hepatocellular carcinoma (HCC) remains incompletely characterized. The present study investigated the expression of miR-375 in human HCC tissues and human liver cancer cell lines; results from a reverse transcription quantitative polymerase chain reaction analysis indicated that the expression of miR-375 was significantly decreased in tissues and live cancer cell lines, compared with normal tissues and PHH cells. Additional studies demonstrated that the upregulation of miR-375 inhibited human liver cancer cell growth via regulation of cell apoptosis. It was also revealed that the receptor tyrosine-protein kinase erbB-2 (ErbB2) gene was a direct target gene of miR-375, and that the regulation of ErbB2 was associated with the human liver cancer growth. Therefore, the present study demonstrated that miR-375 was expressed at low levels both in human HCC tissues and cell line, compared with normal tissues and PHH cells, and that the induction of miR-375 expression may regulate human liver cancer cell function through targeting the ErbB2 gene, which may potentially improve the diagnosis and treatment of patients with HCC in the future.

Avicularin reversed multidrug-resistance in human gastric cancer through enhancing Bax and BOK expressions

5-Fluorouracil (5-Fu) and cisplatin (DDP) as important therapies in treatment of human gastric cancer have been widely determined. However, the therapeutic effects are usually hampered due to drug resistance or toxicity at high concentrations for application. Avicularin (AL, quercetin-3-α-l-arabinofuranoside), a bio-active flavonol isolated from a number of plants, has been reported to display diverse pharmacological properties. In this study, we explored the hypothesis by which AL reversed 5-Fu or DDP resistance in gastric cancer and the underlying molecular mechanism. Here, in vitro, the drug-resistant cancer cells were incubated to AL or DDP alone or the combination of AL and DDP. Then, MTT, colony formation, Hoechst 33258, flow cytometry and western blot analysis were used to investigate the effects of AL in the regulation of drug-resistance gastric cancer cells. The results indicated that AL treatment markedly re-sensitizes the drug resistant cells (SGC-7901/5-Fu and SGC-7901/DDP) to cytotoxicity of 5-Fu or DDP. Molecular mechanism analysis indicated that AL and DDP combination treatment enhanced apoptosis in SGC-7901/DDP cells, accompanied with the up-regulation of cleaved Caspase-3 and PARP, as well as the activation of pro-apoptotic signals, including Bax and BOK. Significantly, down regulation of Bax or BOK expressions using Bax siRNA or BOK siRNA decreased the inhibitory role of DDP in apoptosis of SGC-7901/DDP cells pretreated with AL, demonstrating that AL-reversed DDP resistance was associated with Bax and BOK expression. In vivo, AL and DDP combination significantly reduced gastric tumor growth. Immunohistochemical analysis indicated that co-treatment of AL and DDP significantly induced apoptosis, and reduced tumor cell proliferation in tumor tissue samples. Furthermore, we also found that the Bax, BOK, cleaved Caspase-3 and PARP expression in tumor tissues were highly induced by AL and DDP co-treatment. Together, our findings may provide a novel combination therapeutic strategy in treatment of human gastric cancer.

Circulating microRNAs from the miR-106a-363 cluster on chromosome X as novel diagnostic biomarkers for breast cancer

PURPOSE

Novel noninvasive biomarkers with high sensitivity and specificity for the diagnosis of breast cancer (BC) are urgently needed in clinics. The aim of this study was to explore whether miRNAs from the miR-106a-363 cluster can be detected in the circulation of BC patients and whether these miRNAs can serve as potential diagnostic biomarkers.

METHODS

The expression of 12 miRNAs from the miR-106a-363 cluster was evaluated using qRT-PCR in 400 plasma samples (from 200 BC patients and 200 healthy controls (HCs)) and 406 serum samples (from 204 BC patients and 202 HCs) via a three-phase study. The identified miRNAs were further examined in tissues (32 paired breast tissues), plasma exosomes (from 32 BC patients and 32 HCs), and serum exosomes (from 32 BC patients and 32 HCs).

RESULTS

Upregulated levels of four plasma miRNAs (miR-106a-3p, miR-106a-5p, miR-20b-5p, and miR-92a-2-5p) and four serum miRNAs (miR-106a-5p, miR-19b-3p, miR-20b-5p, and miR-92a-3p) were identified and validated in BC. A plasma 4-miRNA panel and a serum 4-miRNA panel were constructed to discriminate BC patients from HCs. The areas under the receiver-operating characteristic curves of the plasma panel were 0.880, 0.902, and 0.858, and those of the serum panel were 0.910, 0.974, and 0.949 for the training, testing, and external validation phases, respectively. Two overlapping miRNAs (miR-106a-5p and miR-20b-5p) were consistently upregulated in BC tissues. Except for the expression of the plasma-derived exosomal miR-20b-5p, the expression patterns of exosomal miRNAs were concordant between plasma and serum, indicating the potential use of exosomal miRNAs as biomarkers.

CONCLUSION

We identified four plasma miRNAs and four serum miRNAs from the miR-106a-363 cluster as promising novel biomarkers for the diagnosis of BC.

MicroRNA Roles in the Nuclear Factor Kappa B Signaling Pathway in Cancer

Nuclear factor kappa B (NF-κB) is a pluripotent and crucial dimer transcription factor that orchestrates various physiological and pathological processes, especially cell proliferation, inflammation, and cancer development and progression. NF-κB expression is transient and tightly regulated in normal cells, but it is activated in cancer cells. Recently, numerous studies have demonstrated microRNAs (miRNAs) play a vital role in the NF-κB signaling pathway and NF-κB-associated immune responses, radioresistance and drug resistance of cancer, some acting as inhibitors and the others as activators. Although it is still in infancy, targeting NF-κB or the NF-κB signaling pathway by miRNAs is becoming a promising strategy of cancer treatment.

Microfluidic cell sorting by stiffness to examine heterogenic responses of cancer cells to chemotherapy

Cancers consist of a heterogeneous populations of cells that may respond differently to treatment through drug-resistant sub-populations. The scarcity of these resistant sub-populations makes it challenging to understand how to counter their resistance. We report a label-free microfluidic approach to separate cancer cells treated with chemotherapy into sub-populations enriched in chemoresistant and chemosensitive cells based on the differences in cellular stiffness. The sorting approach enabled analysis of the molecular distinctions between resistant and sensitive cells. Consequently, the role of multiple mechanisms of drug resistance was identified, including decreased sensitivity to apoptosis, enhanced metabolism, and extrusion of drugs, and, for the first time, the role of estrogen receptor in drug resistance of leukemia cells. To validate these findings, several inhibitors for the identified resistance pathways were tested with chemotherapy to increase cytotoxicity sevenfold. Thus, microfluidic sorting can identify molecular mechanisms of drug resistance to examine heterogeneous responses of cancers to therapies.

Clinical evaluation of circulating miR-548a-3p and -20a expression in malignant pleural mesothelioma patients

AIM

miRNAs may act as promising diagnostic and prognostic biomarkers of mesothelioma. This study integrates serum  miR-548a-3p and miR-20a expression based on in silico data analysis followed by clinical validation in malignant mesothelioma patients (malignant pleural mesothelioma [MPM]).

PATIENTS & METHODS

Serum miR-548a-3p and  miR-20a level was assessed in the serum of patients with MPM, chronic asbestos exposure and healthy volunteers by quantitative real-time PCR.

RESULTS

The expression of serum miR-548a-3p and  miR-20a was positive in 91.6 and 96.7% MPM patients, respectively. Both miRNAs were able to segregate between cases and controls. The sensitivity of the combined chosen serum miRNAs reached 100% in the diagnosis of MPM.

CONCLUSION

The current work revealed that sera miR-548a-3p and miR-20a may serve as promising novel diagnostic tools for MPM.

Long non-coding RNA LINC00261 sensitizes human colon cancer cells to cisplatin therapy

Colon cancer is one of the most common digestive tumors. The present study aimed to explore the functional role, as well as the underlying mechanism of long non-coding RNA LINC00261 in colon cancer. Expression of LINC00261 was analyzed in colon cancer cell lines and human normal cell lines. Acquired resistance cell lines were then built and the acquired resistance efficiency was detected by evaluating cell viability. Thereafter, the effects of LINC00261 overexpression on cisplatin-resistant colon cancer cells were measured, as well as cell apoptosis, viability, migration, and invasion. Subsequently, we investigated the interaction of LINC00261 and β-catenin. The results showed that the LINC00261 gene was down-regulated in colon cancer cell lines and tissues, and in cisplatin-resistant cells. LINC00261 overexpression might relieve cisplatin resistance of colon cancer cells via promoting cell apoptosis, and inhibiting cell viability, migration, and invasion. Moreover, LINC00261 might down-regulate nuclear β-catenin through restraining β-catenin from cytoplasm into nuclei or it could also promote β-catenin degradation and inhibit activation of Wnt pathway. Finally, LINC00261 reduced cisplatin resistance of colon cancer in vivo and enhanced the anti-colon cancer effect of cisplatin through reducing tumor volume and weight.

Downregulation of microRNA-196a inhibits human liver cancer cell proliferation and invasion by targeting FOXO1

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer in adults and effective therapy for human liver cancer remains a difficult clinical concern. Researchers have demonstrated that microRNAs play important roles in the tumorigenesis and tumor progression of human liver cancer; therefore, regulation of microRNAs may be a new strategy for HCC therapy. MicroRNA-196a (miR-196a) has been reported to be overexpressed in many types of cancers. However, the regulatory effects of miR-196a in human liver cancer are not fully understood. In the present study, we found that miR-196a was overexpressed in human liver cancer cells compared to that observed in normal liver cells. MTT and colony formation assays indicated that downregulation of miR-196a inhibited liver cancer cell proliferation which was due to the induction of cell apoptosis. A mouse model demonstrated that downregulation of miR-196a also inhibited human liver cancer cell migration and invasion in vivo. Further study indicated that FOXO1 is a direct target of miR-196a, and inhibition of FOXO1 promoted human liver cancer cell growth. Taken together, the present study demonstrated that the expression of miR-196a in human liver cancer cells was upregulated; downregulation of miR-196a regulated human liver cancer cell biological functions which could benefit the clinical therapy of human liver cancer in the future.

Upregulation of miRNA-4776 in Influenza Virus Infected Bronchial Epithelial Cells Is Associated with Downregulation of NFKBIB and Increased Viral Survival

Influenza A virus (IAV) infection remains a significant cause of morbidity and mortality worldwide. One key transcription factor that is activated upon IAV infection is nuclear factor Kappa B (NF-κB). NF-κB regulation involves the inhibitor proteins NF-κB inhibitor beta (NFKBIB), (also known as IκB β), which form complexes with NF-κB to sequester it in the cytoplasm. In this study, microarray data showed differential expression of several microRNAs (miRNAs) on exposure to IAV. Target scan analysis revealed that miR-4776, miR-4514 and miR-4742 potentially target NFKBIB messenger RNA (mRNA). Time-course analysis of primary bronchial epithelial cells (HBEpCs) showed that miR-4776 expression is increased within 1 h of infection, followed by its downregulation 4 h post-exposure to IAV. NFKBIB upregulation of miR-4776 correlated with a decrease in NFKBIB expression within 1 h of infection and a subsequent increase in NFKBIB expression 4 h post-infection. In addition, miRNA ago-immunoprecipitation studies and the three prime untranslated region (3' UTR) luciferase assay confirmed that miR-4776 targets NFKBIB mRNA. Furthermore, uninfected HBEpCs transfected with miR-4776 mimic showed decreased expression of NFKBIB mRNA. Overexpression of NFKBIB protein in IAV infected cells led to lower levels of IAV. Taken together, our data suggest that miRNA-4776 modulates IAV production in infected cells through NFKBIB expression, possibly through the modulation of NF-κB.

A panel of microRNA signature in serum for colorectal cancer diagnosis

Dysregulated expression of specific microRNAs (miRNAs) in serum has been recognised as promising diagnostic biomarkers for colorectal cancer (CRC). In the initial screening phase, a total of 32 differentially expressed miRNAs were selected by quantitative reverse transcription polymerase chain reaction (qRT-PCR) based Exiqon panel with 3 CRC pool samples and 1 normal control (NC) pool. Using qRT-PCR, selected serum miRNAs were further confirmed in training (30 CRC VS. 30 NCs) and testing stages (136 CRC VS. 90 NCs). We identified that serum levels of miR-19a-3p, miR-21-5p and miR-425-5p were significantly higher in patients with CRC than in NCs. The areas under the receiver operating characteristic (ROC) curve of the three-miRNA panel were 0.86, 0.74 and 0.87 for the training, testing and the external validation stages (30 CRC VS. 18 NCs), respectively. Significantly, elevated expression of the three miRNAs was also observed in CRC tissues (n = 24). Furthermore, the expression levels of the three miRNAs were significantly elevated in exosomes from CRC serum samples (n = 10). In conclusion, we identified a serum three-miRNA panel for the diagnosis of CRC.

Interactions between anticancer active platinum complexes and non-coding RNAs/microRNAs

Platinum(II) complexes such as cisplatin, carboplatin and oxaliplatin are clinically approved for the therapy of various solid tumors. Challenging pathogenic properties of cancer cells and the response of cancers towards platinum-based drugs are strongly influenced by non-coding small RNA molecules, the microRNAs (miRNAs). Both increased platinum activity and formation of tumor resistance towards platinum drugs are controlled by miRNAs. This review gives an overview of the interactions between platinum-based drugs and miRNAs, and their influence on platinum activity in various cancer types is discussed.

Serum miR-20a is a promising biomarker for gastric cancer

Gastric cancer (GC) is a common type of cancer, particularly in China. Numerous studies have demonstrated that circulating microRNAs (miRNAs) have potential applications as noninvasive biomarkers for cancer diagnosis and prognosis. Microarray-based serum miRNA profiling was performed on the serum of 12 paired pre- and post-operative GC patients to screen differentially expressed serum miRNAs. Twelve different serum miRNAs between pre- and post-operative GC patients were identified. Those miRNAs were verified by real-time quantitative polymerase chain reaction in 110 paired pre- and post-operative serum samples from 55 GC patients. miR-20a was confirmed and demonstrated potential as a GC-associated biomarker. Furthermore, the levels of serum miR-20a were significantly different between GC, nasopharyngeal cancer, colorectal carcinoma, breast cancer and non-cancerous controls. In addition, it was found that serum miR-20a levels correlated with age, tumor stage, differentiated degree and lymph node metastasis in GC. Survival analysis indicated that GC patients with elevated levels of serum miR-20a had poor survival. Thus, serum miR-20a may serve as a molecular marker for diagnosis, evaluating therapeutic efficacy and prognosis, as well as monitoring recurrence in GC patients.

Upregulation of microRNA-34a enhances the DDP sensitivity of gastric cancer cells by modulating proliferation and apoptosis via targeting MET

Cisplatin (DDP) based chemotherapy is still the main strategy of human gastric cancer (GC) treatment. However, drug resistance is a major obstacle for DDP chemotherapy. Recent studies indicated that the resistance could be modulated by the regulation of dysregulated microRNAs (miRs). Previous study also found miR-34a was associated with cell proliferation and apoptosis in human GC; however, the relationship between miR-34a and DDP resistance still remains unexplored. The purpose of this study was to investigate whether miR-34a is associated with DDP resistance in human GC cells. Our study found that the expression of miR-34a was significantly decreased in DDP resistance human GC tissues and DDP resistance human GC SGC7901/DDP cells compared with normal GC tissues and cells. Upregulation of miR-34a enhanced the DDP sensitivity of SGC7901/DDP cells to DDP through the inhibition of cell proliferation and induction of cell apoptosis; on the other hand downregulation of miR-34a could weaken the DDP sensitivity of SGC7901 cells to DDP. Further study found that MET was a direct target of miR-34a and the regulation of MET could affect the DDP sensitivity of SGC7901/DDP cells. Moreover, our study also indicated that up-regulation of miR-34a could decrease the expression of MET in SGC7901/DDP cells. Therefore, our findings suggested miR-34a could modulate human gastric cancer cell DDP sensitivity by regulation of cell proliferation and apoptosis via targeting MET, potentially benefiting human GC treatment in the future.

Emerging Role of miRNAs in the Drug Resistance of Gastric Cancer

Gastric cancer is the third leading cause of cancer mortality worldwide. Unfortunately, most gastric cancer cases are diagnosed in an advanced, non-curable stage and with a limited response to chemotherapy. Drug resistance is one of the most important causes of therapy failure in gastric cancer patients. Although the mechanisms of drug resistance have been broadly studied, the regulation of these mechanisms has not been completely understood. Accumulating evidence has recently highlighted the role of microRNAs in the development and maintenance of drug resistance due to their regulatory features in specific genes involved in the chemoresistant phenotype of malignancies, including gastric cancer. This review summarizes the current knowledge about the miRNAs’ characteristics, their regulation of the genes involved in chemoresistance and their potential as targeted therapies for personalized treatment in resistant gastric cancer.

The Regulatory Roles of MicroRNAs in Bone Remodeling and Perspectives as Biomarkers in Osteoporosis

MicroRNAs are involved in many cellular and molecular activities and played important roles in many biological and pathological processes, such as tissue formation, cancer development, diabetes, neurodegenerative diseases, and cardiovascular diseases. Recently, it has been reported that microRNAs can modulate the differentiation and activities of osteoblasts and osteoclasts, the key cells that are involved in bone remodeling process. Meanwhile, the results from our and other research groups showed that the expression profiles of microRNAs in the serum and bone tissues are significantly different in postmenopausal women with or without fractures compared to the control. Therefore, it can be postulated that microRNAs might play important roles in bone remodeling and that they are very likely to be involved in the pathological process of postmenopausal osteoporosis. In this review, we will present the updated research on the regulatory roles of microRNAs in osteoblasts and osteoclasts and the expression profiles of microRNAs in osteoporosis and osteoporotic fracture patients. The perspective of serum microRNAs as novel biomarkers in bone loss disorders such as osteoporosis has also been discussed.

Decreased miR-198 expression and its prognostic significance in human gastric cancer

Background

MicroRNAs (miRNAs) have been proved to play important roles in the tumorigenesis and development of human gastric cancer (GC). Our study aims to investigate the expression and clinical significance of miR-198 in GC patients.

Methods

Quantitative real-time polymerase chain reaction (RT-PCR) was performed to evaluate miR-198 levels in 106 pairs of GC specimens and adjacent noncancerous tissues. Then, the associations of miR-198 expression with clinicopathological factors and patient’s survival were determined.

Results

The expression levels of miR-198 in GC tissues were significantly lower than those in corresponding noncancerous tissues (p < 0.01). Decreased miR-198 expression was significantly associated with larger tumor size, deeper invasion depth, positive lymph node metastasis, advanced tumor-node-metastasis (TNM) stage, and shorter overall survival. Moreover, multivariate regression analysis identified low miR-198 expression as an independent predictor of poor survival.

Conclusions

These findings suggested that miR-198 downregulation may be associated with progression of GC and that this miR may be an independent prognostic marker for GC patients.