MiR-21, miR-34a, miR-198 and miR-217 as diagnostic and prognostic biomarkers for chronic pancreatitis and pancreatic ductal adenocarcinoma

The role of diagnostic, prognostic, and predictive biomarkers in the management of early pancreatic cancer

Despite modern advances in cancer medicine, pancreatic cancer survival remains unchanged at just 12%. For the small proportion of patients diagnosed with 'early' (upfront or borderline resectable) disease, recurrences are common, and many recur soon after surgery. Whilst chemotherapy has been shown to increase survival in this cohort, the morbidity of surgery renders many candidates unsuitable for adjuvant treatment. Due to this, and the success of upfront chemotherapy in the advanced setting, use of neoadjuvant chemotherapy has been introduced in patients with upfront or borderline resectable disease. Randomized controlled trials have been conducted to compare upfront surgery to neoadjuvant chemotherapy in this patient cohort, opinions on the ideal upfront treatment approach are divided. This lack of consensus has highlighted the need for biomarkers to assist in clinical decision making. This review analyses the potential diagnostic, prognostic and predictive biomarkers that may assist in the diagnosis and management of early (upfront and borderline resectable) pancreatic cancer.

Circulatory miRNAs as Correlates of Elevated Intra-Pancreatic Fat Deposition in a Mixed Ethnic Female Cohort: The TOFI_Asia Study

Ectopic lipid accumulation, including intra-pancreatic fat deposition (IPFD), exacerbates type 2 diabetes risk in susceptible individuals. Dysregulated circulating microRNAs (miRNAs) have been identified as correlating with clinical measures of pancreatitis, pancreatic cancer and type 1 diabetes. The aim of the current study was therefore to examine the association between circulating abundances of candidate miRNAs, IPFD and liver fat deposition as quantified using magnetic resonance imaging (MRI) and spectroscopy (MRS). Asian Chinese (n = 34; BMI = 26.7 ± 4.2 kg/m2) and European Caucasian (n = 34; BMI = 28.0 ± 4.5 kg/m2) females from the TOFI_Asia cohort underwent MRI and MRS analysis of pancreas (MR-%IPFD) and liver fat (MR-%liver fat), respectively, to quantify ectopic lipid deposition. Plasma miRNA abundances of a subset of circulatory miRNAs associated with IPFD and liver fat deposition were quantified by qRT-PCR. miR-21-3p and miR-320a-5p correlated with MR-%IPFD, plasma insulin and HOMA2-IR, but not MR-%liver fat. MR-%IPFD remained associated with decreasing miR-21-3p abundance following multivariate regression analysis. miR-21-3p and miR-320a were demonstrated to be negatively correlated with MR-%IPFD, independent of ethnicity. For miR-21-3p, this relationship persists with the inclusion of MR-%liver fat in the model, suggesting the potential for a wider application as a specific circulatory correlate of IPFD.

Circulating MicroRNAs as Noninvasive Diagnostic and Prognostic Biomarkers in Pancreatic Cancer: A Review

Pancreatic cancer (PC) is one of the most lethal human cancers. Currently, most PC cases are diagnosed at an already advanced stage. Early detection of PC is critical to improving survival rates. Therefore, there is an urgent need to identify biomarkers for the early detection of PC. Recently, circulating miRNAs in whole blood and other body fluids have been reported as promising biomarkers for the early detection of various cancers, including PC. Furthermore, due to minimal invasiveness and technical availability, circulating miRNAs hold promise for further wide usage. As a potential novel molecular marker, circulating miRNAs not only represent promising noninvasive diagnostic and prognostic tools but could also improve the evaluation of tumor classification, metastasis, and curative effect. The purpose of this review is to outline the available information regarding circulating miRNAs as biomarkers for the early detection of PC.

Clinical Value of Circulating microRNAs in Diagnosis and Prognosis of Pancreatic Cancer: A Systematic Review

Pancreatic cancer (PC) is one of the most common cancers and has a high mortality rate due to high invasiveness and rapid progression. Microribonucleic acid (microRNA) plays an essential role in diagnosing PC in the early stages, which improves the five-year survival rate. This systematic review aims to highlight the different subtypes of serum and plasma microRNAs and panel-based assays of microRNAs and how they play a crucial role in the diagnosis and prognosis of PC as a high-sensitive and specific novel biomarker. Following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020 guidelines, an in-depth search was performed by using regular keywords and major Medical Subject Heading (MeSH) keywords in PubMed (MEDLINE), PubMed Central, Google Scholar, Science Direct, and Cochrane Library for articles related to this topic and published between 2013 and 2023, up to April 18, 2023. Further eligibility criteria and quality assessment tools were employed to assess the risk of bias, and 13 articles were finalized to be used in this review. The chosen articles included five cross-sectional studies, six systematic reviews and meta-analyses, and two literature reviews. This review provides strong evidence of the usage of microRNA for early diagnosis. It can also be used to exclude differential diagnoses of other diseases, and its prognostic value for determining metastasis and therapeutic efficacy in PC patients. Also, combining microRNA panels with carbohydrate antigen 19.9 (CA19-9) improves the sensitivity and specificity of microRNA as a biomarker.

Exploring the key genetic association between chronic pancreatitis and pancreatic ductal adenocarcinoma through integrated bioinformatics

Background: Pancreatic ductal adenocarcinoma (PDAC) develops rapidly and has a poor prognosis. It has been demonstrated that pancreatic ductal adenocarcinoma and chronic pancreatitis (CP) have a close connection. However, the underlying mechanisms for chronic pancreatitis transforming into pancreatic ductal adenocarcinoma are still unclear. The purpose of this study was to identify real hub genes in the development of chronic pancreatitis and pancreatic ductal adenocarcinoma. Methods: RNA-seq data of chronic pancreatitis and pancreatic ductal adenocarcinoma were downloaded from the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA) was performed to construct a gene co-expression network between chronic pancreatitis and pancreatic ductal adenocarcinoma. GEO2R and a Venn diagram were used to identify differentially expressed genes. Then visualized networks were constructed with ClueGO, and modules of PPI network were calculated by MCODE plugin. Further validation of the results was carried out in two additional cohorts. Analyses of CEL-coexpressed genes and regulators including miRNAs and transcription factors were performed by using the corresponding online web tool. Finally, the influence of CEL in the tumor immune microenvironment (TIME) was assessed by immune contextual analysis. Results: With the help of WGCNA and GEO2R, four co-expression modules and six hub genes were identified, respectively. ClueGO enrichment analysis and MCODE cluster analysis revealed that the dysfunctional transport of nutrients and trace elements might contribute to chronic pancreatitis and pancreatic ductal adenocarcinoma development. The real hub gene CEL was identified with a markedly low expression in pancreatic ductal adenocarcinoma in external validation sets. According to the miRNA-gene network construction, hsa-miR-198 may be the key miRNA. A strong correlation exists between CEL and TIME after an evaluation of the influence of CEL in TIME. Conclusion: Our study revealed the dysfunctional transport of nutrients and trace elements may be common pathogenesis of pancreatic ductal adenocarcinoma and chronic pancreatitis. Examination on these common pathways and real hub genes may shed light on the underlying mechanism.

Expression of Selected miRNAs in Normal and Cancer-Associated Fibroblasts and in BxPc3 and MIA PaCa-2 Cell Lines of Pancreatic Ductal Adenocarcinoma

Therapy for pancreatic ductal adenocarcinoma remains challenging, and the chances of a complete cure are very limited. As in other types of cancer, the expression and role of miRNAs in controlling the biological properties of this type of tumor have been extensively studied. A better insight into miRNA biology seems critical to refining diagnostics and improving their therapeutic potential. In this study, we focused on the expression of miR-21, -96, -196a, -210, and -217 in normal fibroblasts, cancer-associated fibroblasts prepared from a ductal adenocarcinoma of the pancreas, and pancreatic carcinoma cell lines. We compared these data with miRNAs in homogenates of paraffin-embedded sections from normal pancreatic tissues. In cancer-associated fibroblasts and cancer cell lines, miRNAs differed significantly from the normal tissue. In detail, miR-21 and -210 were significantly upregulated, while miR-217 was downregulated. Similar transcription profiles were earlier reported in cancer-associated fibroblasts exposed to hypoxia. However, the cells in our study were cultured under normoxic conditions. We also noted a relation to IL-6 production. In conclusion, cultured cancer-associated fibroblasts and carcinoma cells reflect miR-21 and -210 expression similarly to the cancer tissue samples harvested from the patients.

Evaluation of circulating miR-216a and miR-217 as biomarkers of pancreatic damage in the L-arginine-induced acute pancreatitis mouse model

We investigated the usefulness of circulating miR-216a-5p and miR-217-5p that are pancreas-enriched micro RNAs (miRNAs) as biomarkers of acute pancreatic damage, and compared them with conventional pancreatic biomarkers in L-arginine-induced acute pancreatitis mouse model. As the results, amylase and lipase levels apparently increased and peaked on Day 3 when acute pancreatitis including acinar cell degeneration/necrosis and inflammatory cell infiltration reached its peak. In contrast, miR-216a-5p and miR-217-5p increased from Day 1 when histopathological findings in the acinar cells were limited to decreased zymogen granules, and the increases in ratios were much higher than those of amylase and lipase. The miRNAs remained at high levels until Day 5 when the pseudo-tubular complex and replacement of inflammatory cells and fibrotic cells were apparent instead of necrosis, whereas amylase and lipase levels decreased to the control levels. Furthermore, we examined the relationship between biomarker levels and histopathological degeneration/necrosis scores in the acinar cells. miR-216a-5p and miR-217-5p levels increased depending on the score of degeneration/necrosis, and all individual miRNAs exceeded the control levels from a score of 2 (focal necrosis), whereas all individual amylase and lipase levels exceeded the control levels at scores of 4 (lobular necrosis) and 3 (sublobular necrosis), respectively. In conclusion, we demonstrated that circulating miR-216a-5p and miR-217-5p could detect pancreatic damage earlier with greater magnitude, and the sensitivity to detect acinar cell degeneration/necrosis was superior to that of conventional biomarkers in the L-arginine-induced acute pancreatitis mouse model.

MicroRNAs as Indicators of Malignancy in Pancreatic Ductal Adenocarcinoma (PDAC) and Cystic Pancreatic Lesions

The dysregulation of microRNAs has recently been associated with cancer development and progression in pancreatic ductal adenocarcinoma (PDAC) and cystic pancreatic lesions. In solid pancreatic tumor tissue, the dysregulation of miR-146, miR-196a/b, miR-198, miR-217, miR-409, and miR-490, as well as miR-1290 has been investigated in tumor biopsies of patients with PDAC and was reported to predict cancer presence. However, the value of the predictive biomarkers may further be increased during clinical conditions suggesting cancer development such as hyperinsulinemia or onset of diabetes. In this specific context, the dysregulation of miR-486 and miR-196 in tumors has been observed in the tumor tissue of PDAC patients with newly diagnosed diabetes mellitus. Moreover, miR-1256 is dysregulated in pancreatic cancer, possibly due to the interaction with long non-coding RNA molecules that seem to affect cell-cycle control and diabetes manifestation in PDAC patients, and, thus, these three markers may be of special or “sentinel value”. In blood samples, Next-generation sequencing (NGS) has also identified a set of microRNAs (miR-20a, miR-31-5p, miR-24, miR-25, miR-99a, miR-185, and miR-191) that seem to differentiate patients with pancreatic cancer remarkably from healthy controls, but limited data exist in this context regarding the prediction of cancer presences and outcomes. In contrast to solid pancreatic tumors, in cystic pancreatic cancer lesions, as well as premalignant lesions (such as intraductal papillary neoplasia (IPMN) or mucinous-cystic adenomatous cysts (MCAC)), the dysregulation of a completely different expression panel of miR-31-5p, miR-483-5p, miR-99a-5p, and miR-375 has been found to be of high clinical value in differentiating benign from malignant lesions. Interestingly, signal transduction pathways associated with miR-dysregulation seem to be entirely different in patients with pancreatic cysts when compared to PDAC. Overall, the determination of these different dysregulation “panels” in solid tumors, pancreatic cysts, obtained via fine-needle aspirate biopsies and/or in blood samples at the onset or during the treatment of pancreatic diseases, seems to be a reasonable candidate approach for predicting cancer presence, cancer development, and even therapy responses.

The promising role and prognostic value of miR-198 in human diseases

The importance of microRNAs (miRNAs or miRs) has attracted more and more attention. MiRNA is an approximately 22-nucleotide, single-stranded, non-coding RNA molecule that affects the expression of downstream target genes. MiRNAs regulate the occurrence and development of human diseases. The objective of this article is to explore the abnormal expression of miR-198 in a variety of human diseases. The relationships between abnormally expressed miR-198 and clinicopathological characteristics are also summarized. Its roles in various diseases and potential molecular mechanisms include involvement in many biological processes, such as cell cycle regulation, proliferation, invasion, migration, apoptosis, and drug resistance. The potential value of miR-198 for disease diagnosis, treatment, and especially, prognosis, are discussed. More in-depth research on miRNA will support the conversion from basic research to clinical applications of this molecule.

Non-coding RNAs underlying the pathophysiological links between type 2 diabetes and pancreatic cancer: A systematic review

Type 2 diabetes is known as a risk factor for pancreatic cancer (PC). Various genetic and environmental factors cause both these global chronic diseases. The mechanisms that define their relationships are complex and poorly understood. Recent studies have implicated that metabolic abnormalities, including hyperglycemia and hyperinsulinemia, could lead to cell damage responses, cell transformation, and increased cancer risk. Hence, these kinds of abnormalities following molecular events could be essential to develop our understanding of this complicated link. Among different molecular events, focusing on shared signaling pathways including metabolic (PI3K/Akt/mTOR) and mitogenic (MAPK) pathways in addition to regulatory mechanisms of gene expression such as those involved in non-coding RNAs (miRNAs, circRNAs, and lncRNAs) could be considered as powerful tools to describe this association. A better understanding of the molecular mechanisms involved in the development of type 2 diabetes and pancreatic cancer would help us to find a new research area for developing therapeutic and preventive strategies. For this purpose, in this review, we focused on the shared molecular events resulting in type 2 diabetes and pancreatic cancer. First, a comprehensive literature review was performed to determine similar molecular pathways and non-coding RNAs; then, the final results were discussed in more detail.

Emerging role and function of miR-198 in human health and diseases

Ever since their discovery, microRNAs (miRNAs/miRs) have astonished us by the plethora of processes they regulate, and thus adding another dimension to the gene regulation. They have been implicated in several diseases affecting cardiovascular, neurodegenerative, hepatic, autoimmune and inflammatory functions. A primate specific exonic miRNA, miR-198 has been vastly studied during the past decade, and shown to have a critical role in wound healing. The aberrant expression of miR-198 was first reported in schizophrenia, linking it to neural development. Later, its dysregulation and tumor suppressive role was reported in hepatocellular carcinoma. However, this was just a beginning, and after which there was an explosion of reports linking miR-198 deregulation to cancers and other ailments. The first target to be identified for miR-198 was Cyclin T1 in monocytes affecting HIV1 replication. Depending on the type of cancer, miR-198 has been shown to function either as a tumor suppressor or an oncomir. Interestingly, miR-198 is not only known to regulate multiple targets and pathways, but also is itself regulated by several circular RNAs and long-non-coding RNAs, highlighting a complex regulatory network. This review highlights the currently understood mechanism and regulation of miR-198 in different diseases, and its possible diagnostic and therapeutic potential.

Blood small extracellular vesicles derived miRNAs to differentiate pancreatic ductal adenocarcinoma from chronic pancreatitis

BACKGROUND

The differential diagnosis of pancreatic ductal adenocarcinoma (PDAC) from chronic pancreatitis (CP) is clinically challenging due to a lack of minimally invasive diagnosis methods. MicroRNAs (miRNAs) derived from small extracellular vesicles (EVs) in the blood have been reported as a promising diagnosis biomarker for various types of cancer. However, blood small EV miRNA signatures and their diagnostic value to differentiate between PDAC and CP remain to be determined.

METHODS

In this study, 107 patients with PDAC or CP were recruited, and 90 patients were finally enrolled for a training cohort (n = 48) and test cohort (n = 42). Small RNA sequencing was used to assess the expression of blood small EV miRNAs in these patients.

RESULTS

The linear model from the differentially expressed blood small EV miR-95-3p divided by miR-26b-5p showed an average sensitivity of 84.1% and an average specificity of 96.6% to identify PDAC from CP in the training cohort and the test cohort, respectively. When the model was combined with serum carbohydrate antigen 19-9 (CA19-9), the average sensitivity increased to 96.5%, and the average specificity remained at 96.4% of both cohorts, which demonstrated the best performance of all the published biomarkers for distinguishing between PDAC and CP. The causal analysis performed using the Bayesian network demonstrated that miR-95-3p was associated with a "consequence" of "cancer" and miR-26b-5p as a "cause" of "pancreatitis." A subgroup analysis revealed that blood small EV miR-335-5p/miR-340-5p could predict metastases in both cohorts and was associated with an overall survival (p = 0.020).

CONCLUSIONS

This study indicated that blood small EV miR-95-3p/miR-26b-5p and its combination with serum levels of CA19-9 could separate PDAC from CP, and miR-335-5p/miR-340-5p was identified to associate with PDAC metastasis and poor prognosis. These results suggested the potentiality of blood small EV miRNAs as differential diagnosis and metastases biomarkers of PDAC.

The role of circulating miRNAs and CA19-9 in pancreatic cancer diagnosis

Diagnosis and treatment of pancreatic ductal adenocarcinoma (PA) remains a challenge in clinical practice. The aim of this study was to assess the role of microRNAs (miRNAs-21, -23a, -100, -107, -181c, -210) in plasma and tissue as possible biomarkers in the diagnosis of PA. Samples of plasma (PAp-n = 13), pancreatic tumors (PAt-n = 18), peritumoral regions (PPT-n = 9) were collected from patients during the surgical procedure. The control group consisted of samples from patients submitted to pancreatic surgery for trauma or cadaveric organs (PC-n = 7) and healthy volunteers donated blood (PCp-n = 6). The expression profile of microRNAs was measured in all groups using RT-PCR, serum CA19-9 levels were determined in PA and PC. In tissue samples, there was a difference in the expression of miRNAs-21, -210 (p < 0.05) across the PAt, PC and PPT groups. The PAp showed overexpression of miRNAs-181c, -210 (p < 0.05) when compared to PCp. The combination of miRNAs-21, -210 tissue expression and serum CA19-9 showed 100% accuracy in the diagnosis of PA, as well as miR-181c expression in the plasma (PApxPCp). The expression of microRNAs in plasma proved to be a promising tool for a noninvasive detection test for PA, as well as further studies will evaluate the utility of microRNAs expression as biomarkers for prognostic and response to therapy in PA.

Identification of differentially expressed microRNAs in primary esophageal achalasia by next-generation sequencing

Molecular knowledge regarding the primary esophageal achalasia is essential for the early diagnosis and treatment of this neurodegenerative motility disorder. Therefore, there is a need to find the main microRNAs (miRNAs) contributing to the mechanisms of achalasia. This study was conducted to determine some patterns of deregulated miRNAs in achalasia. This case-control study was performed on 52 patients with achalasia and 50 nonachalasia controls. The miRNA expression profiling was conducted on the esophageal tissue samples using the next-generation sequencing (NGS). Differential expression of miRNAs was analyzed by the edgeR software. The selected dysregulated miRNAs were additionally confirmed using the quantitative reverse transcription polymerase chain reaction (qRT-PCR). Fifteen miRNAs were identified that were significantly altered in the tissues of the patients with achalasia. Among them, three miRNAs including miR-133a-5p, miR-143-3p, and miR-6507-5p were upregulated. Also, six miRNAs including miR-215-5p, miR-216a-5p, miR-216b-5p, miR-217, miR-7641 and miR-194-5p were downregulated significantly. The predicted targets for the dysregulated miRNAs showed significant disease-associated pathways like neuronal cell apoptosis, neuromuscular balance, nerve growth factor signaling, and immune response regulation. Further analysis using qRT-PCR showed significant down-regulation of hsa-miR-217 (p-value = 0.004) in achalasia tissue. Our results may serve as a basis for more future functional studies to investigate the role of candidate miRNAs in the etiology of achalasia and their application in the diagnosis and probably treatment of the disease.

The comprehensive landscape of miR-34a in cancer research

MicroRNA-34 (miR-34) plays central roles in human diseases, especially cancers. Inactivation of miR-34 is detected in cancer cell lines and tumor tissues versus normal controls, implying its potential tumor-suppressive effect. Clinically, miR-34 has been identified as promising prognostic indicators for various cancers. In fact, members of the miR-34 family, especially miR-34a, have been convincingly proved to affect almost the whole cancer progression process. Here, a total of 512 (miR-34a, 10/21), 85 (miR-34b, 10/16), and 114 (miR-34c, 10/14) putative targets of miR-34a/b/c are predicted by at least ten miRNA databases, respectively. These targets are further analyzed in gene ontology (GO), KEGG pathway, and the Reactome pathway dataset. The results suggest their involvement in the regulation of signal transduction, macromolecule metabolism, and protein modification. Also, the targets are implicated in critical signaling pathways, such as MAPK, Notch, Wnt, PI3K/AKT, p53, and Ras, as well as apoptosis, cell cycle, and EMT-related pathways. Moreover, the upstream regulators of miR-34a, mainly including transcription factors (TFs), lncRNAs, and DNA methylation, will be summarized. Meanwhile, the potential TF upstream of miR-34a/b/c will be predicted by PROMO, JASPAR, Animal TFDB 3.0, and GeneCard databases. Notably, miR-34a is an attractive target for certain cancers. In fact, miR-34a-based systemic delivery combined with chemotherapy or radiotherapy can more effectively control tumor progression. Collectively, this review will provide a panorama for miR-34a in cancer research.

Improving Gemcitabine Sensitivity in Pancreatic Cancer Cells by Restoring miRNA-217 Levels

Chemoresistance is a major problem in the therapeutic management of pancreatic cancer, concurring to poor clinical outcome. A number of mechanisms have been proposed to explain resistance to gemcitabine, a standard of care for this malignancy, among which is included aberrant miRNA expression. In the current study, we investigated the role of miR-217, which is strongly down-regulated in cancerous, compared to normal, pancreatic tissues or cells, in sensitizing human pancreatic cancer cell lines to this drug. The low expression of miR-217 in pancreatic cancer patients was confirmed in two gene expression datasets (GSE41372 and GSE60980), and the prognostic value of two target genes (ANLN and TRPS1), was estimated on clinical data from the Tumor Cancer Genome Atlas (TCGA). Transfecting miR-217 mimic in pancreatic cancer cells reduced viability, enhanced apoptosis, and affected cell cycle by promoting a S phase arrest in gemcitabine-treated cells. Moreover, in drug-exposed cells subjected to miR-217 forced expression, a down-regulation for several genes involved in cancer drug resistance was observed, many of which are cell cycle regulators, such as CCND1, CCNE1, CDK2, CDKN1A, CDKN1B, while others, such as ARNT, BRCA1, BRCA2, ELK1, EGFR, ERBB4, and RARA are involved in proliferation and cell cycle progression. Our results support the notion that miR-217 enhances pancreatic cancer sensitivity to gemcitabine, mainly impairing cell cycle progression.

Non-coding RNA biomarkers in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies, which is usually diagnosed at an advanced stage. The late disease diagnosis, the limited availability of effective therapeutic interventions and lack of robust diagnostic biomarkers, are some of the primary reasons for the dismal 5-year survival rates (∼8%) in patients with PDAC. The pancreatic cancer develops through accumulation of a series of genomic and epigenomic alterations which lead to the transformation of normal pancreatic epithelium into an invasive carcinoma - a process that can take up to 15-20 years to develop, from the occurrence of first initiating mutational event. These facts highlight a unique window of opportunity for the earlier detection of PDAC, which could allow timely disease interception and improvement in the overall survival outcomes in patients suffering from this fatal malignancy. Non-coding RNAs (ncRNAs) have been recognized to play a central role in PDAC pathogenesis and are emerging as attractive candidates for biomarker development in various cancers, including PDAC. More specifically, the ncRNAs play a pivotal role in PDAC biology as they affect tumor growth, migration, and invasion by regulating cellular processes including cell cycle, apoptosis, and epithelial-mesenchymal transition. In this review, we focus on three types of well-established ncRNAs - microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) - and discuss their potential as diagnostic, prognostic and predictive biomarkers in PDAC.

Prognostic value of microRNAs in pancreatic cancer: a meta-analysis

BACKGROUND

The prognostic impact of microRNA (miRNA) expression levels in pancreatic cancer (PC) has been estimated for years, but the outcomes are controversial and heterogeneous. Therefore, we comprehensively reviewed the evidence collected on miRNA expression in PC to determine this effect.

RESULTS

PC patients with high miR-21 (HR=2.61, 95%CI=1.68-4.04), miR-451a (HR=2.23, 95%CI=1.23-4.04) or miR-1290 (HR=1.43, 95%CI=1.04-1.95) levels in blood had significantly poorer OS (P<0.05). Furthermore, PC patients with high miR-10b (HR=1.73, 95%CI=1.09-2.76), miR-17-5p (HR=1.91, 95%CI=1.30-2.80), miR-21 (HR=1.90, 95%CI=1.61-2.25), miR-23a (HR=2.18, 95%CI=1.52-3.13), miR-155 (HR=2.22, 95%CI=1.27-3.88), miR-203 (HR=1.65, 95%CI=1.14-2.40), miR-221 (HR=1.72, 95%CI=1.08-2.74), miR-222 levels (HR=1.72, 95%CI=1.02-2.91) or low miR-29c (HR=1.39, 95%CI=1.08-1.79), miR-126 (HR=1.55, 95%CI=1.23-1.95), miR-218 (HR=2.62, 95%CI=1.41-4.88) levels in tissues had significantly shorter OS (P<0.05).

CONCLUSIONS

In summary, blood miR-21, miR-451a, miR-1290 and tissue miR-10b, miR-17-5p, miR-21, miR-23a, miR-29c, miR-126, miR-155, miR-203, miR-218, miR-221, miR-222 had significant prognostic value.

METHODS

We searched PubMed, EMBASE, Web of Science and Cochrane Database of Systematic Reviews to recognize eligible studies, and 57 studies comprising 5445 PC patients and 15 miRNAs were included to evaluate the associations between miRNA expression levels and overall survival (OS) up to June 1, 2019. Summary hazard ratios (HR) with 95% confidence intervals (CI) were calculated to assess the effect.

microRNAs targeting cellular cholesterol: implications for combating anticancer drug resistance

Over sixty percent of all mammalian protein-coding genes are estimated to be regulated by microRNAs (miRNAs), and unsurprisingly miRNA dysregulation has been linked with cancer. Aberrant miRNA expression in cancer cells has been linked with tumourigenesis and drug resistance. In the past decade, increasing number of studies have demonstrated that cholesterol accumulation fuels tumour growth and contributes to drug resistance, therefore, miRNAs controlling cholesterol metabolism and homeostasis are obvious hypothetical targets for investigating their role in cholesterol-mediated drug resistance in cancer. In this review, we have collated published evidences to consolidate this hypothesis and have scrutinized it by utilizing computational tools to explore the role of miRNAs in cholesterol-mediated drug resistance in breast cancer cells. We found that hsa-miR-128 and hsa-miR-223 regulate genes mediating lipid signalling and cholesterol metabolism, cancer drug resistance and breast cancer genes. The analysis demonstrates that targeting these miRNAs in cancer cells presents an opportunity for developing new strategies to combat anticancer drug resistance.

Extracellular vesicles microRNA analysis in type 1 autoimmune pancreatitis: Increased expression of microRNA-21

BACKGROUND

The molecular basis of type 1 autoimmune pancreatitis (AIP) remains unclear. Recent attention on the role of extracellular vesicles microRNA (EV miRNA) in immune homeostasis has prompted us to perform an extensive miRNA screening of serum-derived EV in AIP.

METHODS

EV miRNA expression was analyzed using microarrays in AIP, chronic pancreatitis (CP), and healthy adult (HC) samples (n = 10 from each group). Differences in signals, > 3 or <1/3 times, represented significant differences in expression. Another cohort of AIP (n = 14), CP (n = 10), and HC (n = 10) samples of EV miRNA was analyzed using reverse-transcription polymerase chain reaction (RT-PCR). miRNA expression in pancreatic tissues was evaluated using in situ hybridization (ISH) in three additional subjects from each group.

RESULTS

Signals of eight miRNAs (miR-659-3p, -27a-3p, -99a-5p, -21-5p, -205-5p, -100-5p, -29c-3p, and -125b-1-3p) were significantly higher, while those of two miRNAs (miR-4252 and -5004-5p) were significantly lower in AIP than in HC. EV miR-21-5p was significantly up-regulated in AIP than in HC (P = 0.035) and CP (P = 0.048). The number of miR-21-5p positive inflammatory cells was significantly elevated in AIP than in CP (P = 0.014).

CONCLUSIONS

Circulating EVs exhibited altered miRNA expression patterns with elevated miR-21-5p in AIP when compared with those in HC and CP. miR-21-5p was highly expressed in pancreatic inflammatory cells in AIP. Our data suggests that miR-21-5p may be involved in the regulation of effector pathways in the pathophysiology of AIP, thus differentiating AIP from CP.

MicroRNAs Targeting MYC Expression: Trace of Hope for Pancreatic Cancer Therapy. A Systematic Review

Background

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignancies and a major health problem worldwide. There were no major advances in conventional treatments in inhibiting tumor progression and increasing patient survival time. In order to suppress mechanisms responsible for tumor cell development such as those with oncogenic roles, more advanced therapeutic strategies should be sought. One of the most important oncogenes of pancreatic cancer is the MYC gene. The overexpression of MYC can activate many tumorigenic processes such as cell proliferation and pancreatic cancer cell invasion. MiRNAs are important molecules that are confirmed by targeting mRNA transcripts to regulate the expression of the MYC gene. Therefore, restoring MYC-repressing miRNAs expression tends to be an effective method of treating MYC-driven cancers.

Objective

The purpose of this study was to identify all validated microRNAs targeting C-MYC expression to inhibit PDAC progression by conducting a systematic review.

Methods

In this systematic review study, the papers published between 2000 and 2020 in major online scientific databases including PubMed, Scopus, and Web of Science were screened, following inclusion and exclusion criteria. We extracted all the experimental studies that showed miRNAs could target the expression of the MYC gene in PDAC.

Results

Eight papers were selected from a total of 89 papers. We found that six miRNAs (Let-7a, miR-145, miR-34a, miR-375, miR-494, and miR-148a) among the selected studies were validated for targeting MYC gene and three of them confirmed Let-7a as a direct MYC expression regulator in PC cells. Finally, we summarized the latest shreds of evidence of experimentally validated miRNAs targeting the MYC gene with respect to PDAC’s therapeutic potential.

Conclusion

Restoring the expression of MYC-repressing miRNAs tends to be an effective way to treat MYC-driven cancers such as PDAC. Several miRNAs have been proposed to target this oncogene via bioinformatics tools, but only a few have been experimentally validated for pancreatic cancer cells and models. Further studies should be conducted to find the interaction network of miRNA-MYC to develop more successful therapeutic strategies for PC, using the synergistic effects of these miRNAs.

The Promising Role of miR-21 as a Cancer Biomarker and Its Importance in RNA-Based Therapeutics

MicroRNAs are small noncoding transcripts that posttranscriptionally regulate gene expression via base-pairing complementarity. Their role in cancer can be related to tumor suppression or oncogenic function. Moreover, they have been linked to processes recognized as hallmarks of cancer, such as apoptosis, invasion, metastasis, and proliferation. Particularly, one of the first oncomiRs found upregulated in a variety of cancers, such as gliomas, breast cancer, and colorectal cancer, was microRNA-21 (miR-21). Some of its target genes associated with cancer are PTEN (phosphatase and tensin homolog), PDCD4 (programmed cell death protein 4), RECK (reversion-inducing cysteine-rich protein with Kazal motifs), and STAT3 (signal transducer activator of transcription 3). As a result, miR-21 has been proposed as a plausible diagnostic and prognostic biomarker, as well as a therapeutic target for several types of cancer. Currently, research and clinical trials to inhibit miR-21 through anti-miR-21 oligonucleotides and ADM-21 are being conducted. As all of the evidence suggests, miR-21 is involved in carcinogenic processes; therefore, inhibiting it could have effects on more than one type of cancer. However, whether miR-21 can be used as a tissue-specific biomarker should be analyzed with caution. Consequently, the purpose of this review is to outline the available information and recent advances regarding miR-21 as a potential biomarker in the clinical setting and as a therapeutic target in cancer to highlight its importance in the era of precision medicine.

Correlation between FAK and EGF-Induced EMT in Colorectal Cancer Cells

Epithelial-mesenchymal transition (EMT) plays an important role in the invasion and metastasis of colorectal cancer, which is mediated by FAK and EGF. However, whether FAK participates in EMT in colorectal cancer cells through the EGF/EGFR signaling pathway remains unknown. The aim of this study was to investigate the effector mechanisms of FAK in the process of EGF-induced EMT in colorectal cancer cells and to determine whether miR-217 is involved in this process. Caco-2 cancer cells were routinely cultured with and without treatment with 100 ng/mL EGF, and changes in cell morphology were observed using an inverted microscope. In addition, a transwell assay was used to detect cell migration under the condition of EGF treatment. The expression of FAK, pFAK, E-cadherin, vimentin, and β actin was assessed by western blotting, and the expression of miR-217 was assessed using real-time PCR. We found that EGF induced EMT in colorectal cancer cells and enhanced cell migration and invasion ability. Moreover, FAK was involved in the EGF-induced EMT of colorectal cancer cells. EGF upregulated the expression of E-cadherin in colorectal cancer cells by activating FAK, and miR-217 was found to participate in EGF-induced EMT in colorectal cancer cells. Our findings indicate that EGF induces EMT in colorectal cancer cells by activating FAK, and miR-217 is involved in the EGF/FAK/E-cadherin signaling pathway.

Comparison of Native Aspirates and Cytological Smears Obtained by EUS-Guided Biopsies for Effective DNA/RNA Marker Testing in Pancreatic Cancer

We compare two types of pancreatic carcinoma samples obtained by EUS-guided fine needle biopsy (EUS-FNB) in terms of the success rates and clinical validity of analysis of two most commonly investigated DNA/RNA pancreatic cancer markers, KRAS mutations and miR-21 expression. 118 patients with pancreatic ductal adenocarcinoma underwent EUS-FNB. The collected sample was divided, one part was stored in a stabilizing solution as native aspirate (EUS-FNA) and second part was processed into the cytological smear (EUS-FNC). DNA/RNA extraction was followed by analysis of KRAS mutations and miR-21 expression. For both sample types, the yields of DNA/RNA extraction and success rates of KRAS mutation and miRNA expression were evaluated. Finally, the resulting KRAS mutation frequency and miR-21 prognostic role were compared to literature data from tissue resections. The overall amount of isolated DNA/RNA from EUS-FNC was lower compared to the EUS-FNA, average yield 10 ng vs 147 ng for DNA and average yield 164 vs. 642 ng for RNA, but the success rates for KRAS and miR-21 analysis was 100% for both sample types. The KRAS-mutant detection frequency in EUS-FNC was 12% higher than in EUS-FNA (90 vs 78%). The prognostic role of miR-21 was confirmed in EUS-FNC (p = 0.02), but did not reach statistical significance in EUS-FNA (p = 0.06). Although both types of EUS-FNB samples are suitable for DNA/RNA extraction and subsequent DNA mutation and miRNA expression analysis, reliable results with clinical validity were only obtained for EUS-FNC.

Clinical value of circular RNAs and autophagy-related miRNAs in the diagnosis and treatment of pancreatic cancer

BACKGROUND

Circular RNAs (circRNAs) are a special group of long-chain and non-coding RNAs characterized by a closed-loop structure without 3' and 5' polarity. In recent years, studies have demonstrated that circRNAs act as microRNA (miRNA) sponges to regulate the function of miRNAs. Increasing evidence indicates that circRNAs and targeted miRNAs are involved in the development, progression and metastasis of various cancers and drug resistance. A number of miRNAs are known to be associated with the pathogenesis, development and treatment of pancreatic cancer by regulating the autophagic activity.

DATA SOURCES

A comprehensive literature search was executed in PubMed and EMBASE using the medical subject headings (MeSH) terms "Pancreatic Neoplasms", "autophagy", "RNA, circular" and "microRNA". We also used text terms such as "diagnosis", "prognosis" and "biomarker" to supplement the results.

RESULTS

Autophagy-related miRNAs is closely related to pancreatic cancer. On basis of the retrieval results, we summarized the synthesis, features and functions of circRNAs and analyzed the association between autophagy-related miRNAs and pancreatic cancer.

CONCLUSIONS

circRNAs act as the miRNA sponges and there is an association between miRNAs and autophagy, which provides a new concept to broaden the knowledge about the mechanisms underlying the development, progression and metastasis of pancreatic cancer. Additionally, clinical value of circRNAs and autophagy-related miRNAs in the diagnosis and treatment of pancreatic cancer would be further verified with in-depth researches.

Are ENT1/ENT1, NOTCH3, and miR-21 Reliable Prognostic Biomarkers in Patients with Resected Pancreatic Adenocarcinoma Treated with Adjuvant Gemcitabine Monotherapy?

Evidence on equilibrative nucleoside transporter 1 (ENT1) and microRNA-21 (miR‑21) is not yet sufficiently convincing to consider them as prognostic biomarkers for patients with pancreatic ductal adenocarcinoma (PDAC). Here, we investigated the prognostic value of ENT1/ENT1, miR-21, and neurogenic locus homolog protein 3 gene (NOTCH3) in a well-defined cohort of resected patients treated with adjuvant gemcitabine chemotherapy (n = 69). Using a combination of gene expression quantification in microdissected tissue, immunohistochemistry, and univariate/multivariate statistical analyses we did not confirm association of ENT1/ENT1 and NOTCH3 with improved disease-specific survival (DSS). Low miR-21 was associated with longer DSS in patients with negative regional lymph nodes or primary tumor at stage 1 and 2. In addition, downregulation of ENT1 was observed in PDAC of patients with high ENT1 expression in normal pancreas, whereas NOTCH3 was upregulated in PDAC of patients with low NOTCH3 levels in normal pancreas. Tumor miR‑21 was upregulated irrespective of its expression in normal pancreas. Our data confirmed that patient stratification based on expression of ENT1/ENT1 or miR‑21 is not ready to be implemented into clinical decision-making processes. We also conclude that occurrence of ENT1 and NOTCH3 deregulation in PDAC is dependent on their expression in normal pancreas.

Knockout of Acinar Enriched microRNAs in Mice Promote Duct Formation But Not Pancreatic Cancer

The pancreatic acinar-enriched miR-216a, miR-216b and miR-217 are encoded within the miR217HG. These miRNAs have been purported to play a tumor suppressive role as their expression is reduced in both human and mouse pancreatic ductal adenocarcinoma (PDAC). To examine this possibility, we generated individual, germline knockout (KO) mice of miR-216a, miR-216b or miR-217. Unlike our previous study showing germline deletion of the miR217HG was embryonic lethal, CRISPR-Cas9 deleted portions of the 5' seed region of the miRNAs produced live births. To investigate possible phenotypes during pancreatic acinar ductal metaplasia (ADM), pancreatic acini from wild type and KO mice were plated on collagen and allowed to transdifferentiate over 4 days. Acini from each of the three miRNA KO mice produced greater numbers of ducts compared to controls. Evaluation of the gene expression during in vitro ADM demonstrated an increase in Krt19 and a reduction in acinar genes (Carboxypeptidase A1, Amylase2a) on day 4 of the transdifferentiation. Recovery was delayed for the miR-216a and miR-216b KOs following caerulein-induced acute pancreatitis. Also predominate in the caerulein treated miR-216a and miR-216b KO mice was the presence of pancreatic duct glands (PDGs). To further establish a phenotype, miRNA KO mice were crossed with EL-KRASG12D (EK) mice and followed up to 13 months of age. While all mice developed severe dysplasia and cystic papillary neoplasms, there existed no apparent phenotypic difference in the miRNA KO/EK mice compared to EK mice. Our data does not support a tumor suppressor role for miR-216a, miR-216b or miR-217 in PDAC and emphasizes the need for phenotypic evaluation of miRNAs in complex in vivo models beyond that performed using cell culture.

Clinical value of microRNA-198-5p downregulation in lung adenocarcinoma and its potential pathways

Lung adenocarcinoma (LUAD), the main subtype of non-small cell lung cancer, is known to be regulated by various microRNAs (miRs/miRNAs); however, the role of miR-198-5p in LUAD has not been clarified. In the present study, the clinical value of miR-198-5p in LUAD and its potential molecular mechanism was evaluated. miR-198-5p expression was examined by reverse transcription-quantitative PCR (RT-qPCR) in 101 paired LUAD and adjacent normal lung tissues. Subsequently, the miR-198-5p expression level was determined from microarray data from the Gene Expression Omnibus, ArrayExpress and by meta-analyses. Furthermore, the target mRNAs of miR-198-5p from 12 miRNA-mRNA predictive tools were intersected with The Cancer Genome Atlas (TCGA)-based differentially expressed genes. In addition, Gene Ontology annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were conducted to determine the possible mechanism of miR-198-5p in LUAD. The Search Tool for the Retrieval of Interacting Genes/Proteins database was employed to construct a protein-protein interaction network among the potential target genes of miR-198-5p. The results showed that miR-198-5p expression was lower in LUAD tissues than in adjacent non-cancerous lung tissues (4.469±2.495 vs. 5.301±2.502; P=0.015). Meta-analyses, including the data from the present study and online microarray data, also verified the downregulation of miR-198-5p in 584 cases of LUAD. The expression of miR-198-5p was associated with the age, blood vessel invasion, Tumor-Node-Metastasis stage, and lymph node metastasis of patients with LUAD and served as an independent prognostic factor for survival. The hub genes of miR-198-5p were upregulated in LUAD, according to TCGA and The Human Protein Atlas. For the KEGG pathway analysis, the most enriched KEGG pathway was the p53 signaling pathway (P=1.42×10⁻⁶). These findings indicated that the downregulation of miR-198-5p may play a pivotal role in the development of LUAD by targeting various signaling pathways.

Pre-operative Plasma miR-21-5p Is a Sensitive Biomarker and Independent Prognostic Factor in Patients with Pancreatic Ductal Adenocarcinoma Undergoing Surgical Resection

Blood plasma microRNAs (miRNAs) are emerging as a clinically useful tool for non-invasive detection and prognosis estimation in various cancer types including pancreatic ductal adenocarcinoma (PDAC). The aim of the present study was to provide an independent validation of circulating miRNAs identified in previous studies as diagnostic and/or prognostic biomarkers in PDAC. Based on the literature search, 6 miRNAs were chosen as candidates for independent validation; miR-21-5p, miR-375, miR-155, miR-17-5p, miR-126-5p and miR-1290. Validation of these miRNAs was performed in a cohort of 25 patients with PDAC undergoing surgical resection and 24 healthy donors. Plasma levels of miRNAs were determined using quantitative real-time PCR. We confirmed significantly higher levels of all tested miRNA in blood plasma of PDAC patients in comparison to healthy controls with miR-21-5p showing the highest analytical performance (p<0.001; AUC>0.99). Increased levels of miR-21-5p (p=0.045) and miR-375 (p=0.013) were significantly associated with overall survival. Multivariate analysis demonstrated that miR-21-5p is a significant unfavorable prognostic factor independent on other clinical variables including adjuvant chemotherapy (hazard ratio 2.95; 95% CI 1.06-8.18; p=0.038). Our preliminary data indicate promising diagnostic and prognostic utility of plasma miR-21-5p in PDAC patients.

MiR-21-3p aggravates injury in rats with acute hemorrhagic necrotizing pancreatitis by activating TRP signaling pathway

To evaluate the expression and effect of miR-21-3p in pancreas and lung injury of acute hemorrhagic necrotizing pancreatitis (AHNP) rats. AHNP rat model was constructed via retrograde injection of 5% sodium taurocholate into biliary pancreatic duct. Then rats were divided into normal, sham, AHNP, mimics negative control (NC), miR-21-3p mimics, inhibitors NC, miR-21-3p inhibitors, miR-21-3p mimics + phosphate buffer saline and miR-21-3p mimics + Gd³⁺ groups (N = 10 in each group). The expression of miR-21-3p, TRP signaling pathway factor, apoptosis related protein and histology were studied in pancreatic and lung tissues. Apoptosis of pancreatic acinar cells was detected. Oxidative stress indexes were detected in lung tissues. The level of PaO₂ and PaCO₂ and the expression of amylase, lipase and inflammatory factors were detected in blood. Compared with normal and sham groups, the miR-21-3p expression was increased in pancreatic and lung tissues of AHNP rats. MiR-21-3p expression was successfully regulated. Down-regulated miR-21-3p promoted apoptosis of pancreatic acinar cells and restored its function in AHNP rats. Up-regulated miR-21-3p reduced the lung oxygenation function, promoted pathological damage, and aggravated oxidative stress injury in AHNP rats. Meanwhile, up-regulated miR-21-3p also promoted the expression of serum enzymes and inflammatory factors, and activated TRP signaling pathway in AHNP rats. And miR-21-3p aggravated pancreatitis and lung injury by activating transient receptor potential (TRP) signaling pathway in AHNP rats. miR-21-3p promoted the pancreatic injury, inhibited apoptosis of necrotic acinar cells and aggravated lung oxidative stress injury by activating TRP signaling pathway in AHNP rats.

The Use of Biomarkers in Early Diagnostics of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal solid malignancies with increasing incidence. The poor prognosis is due to the aggressive nature of the tumor, late detection, and the resistance to chemotherapy and radiotherapy. A radical surgery procedure is the only treatment that has been shown to improve the 5-year survival rate to 20-25%. However, the majority of patients (80-85%) are diagnosed with locally advanced or metastatic disease and just 15-20% patients are diagnosed in an early stage allowing them to undergo the potentially curative surgical resection. The early detection of PDAC without the use of invasive methods is challenging and discovery of a cost-effective biomarker with high specificity and sensitivity could significantly improve the treatment and survival in these patients. In this review, we summarize current and newly examined biomarkers in early PDAC detection.

A novel regulatory function for miR-217 targetedly suppressing fibronectin expression in keloid fibrogenesis

Fibronectin (FN) plays a critical role in the development and progression of keloid scarring (KS). In the present study, we hypothesized that a post-translational mechanism of microRNAs regulated the expression of FN in keloid scarring fibroblasts (KSFBs). Here, we collected 20 KS tissues and paired corresponding adjacent normal tissues from clinical patients and measured the expression of miRNA-217. First, by using PicTar, TargetScan and miRBase database, we found that miRNA-217 might be a regulator of FN in human species. Based on these hypotheses, the expression of miRNA-217 and FN in KS tissues was investigated. The results demonstrated that the expression of miRNA-217 was greatly suppressed, and FN was increased in KS tissues. Intriguingly, the expression levels of endogenous miRNA-217 negatively correlated with the FN mRNA levels (Pearson's correlation coefficient = -0.683, P < 0.001). In vitro, miRNA-217 could regulate FN through the predicted binding sites in its 3'-UTR. miRNA-217 played an impact on cell proliferation and apoptosis, thereby regulating KSFBs growth. Moreover, miRNA-217 gain-of function decreased FN, Col-1 and Col-3 protein expression, and miRNA-217 loss-of function increased FN, Col-1 and Col-3 protein expression in KSFBs. In conclusion, overexpressed miRNA-217 could inhibit KSFBs growth, and the underlying mechanism was mediated, at least partially, through the suppression of FN expression. But above all, miRNA-217 might play a potential therapeutic avenue for the treatment of keloid fibrogenesis.

Clinical value of miR-198-5p in lung squamous cell carcinoma assessed using microarray and RT-qPCR

Background

To examine the clinical value of miR-198-5p in lung squamous cell carcinoma (LUSC).

Methods

Gene Expression Omnibus (GEO) microarray datasets were used to explore the miR-198-5p expression and its diagnostic value in LUSC. Real-time reverse transcription quantitative polymerase chain reaction was used to evaluate the expression of miR-198-5p in 23 formalin-fixed, paraffin-embedded (FFPE) LUSC tissues and corresponding non-cancerous tissues. The correlation between miR-198-5p expression and clinic pathological features was assessed. Meanwhile, putative target messenger RNAs of miR-198-5p were identified based on the analysis of differentially expressed genes in the Cancer Genome Atlas (TCGA) and 12 miRNA prediction tools. Subsequently, the putative target genes were sent to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses.

Results

MiR-198-5p was low expressed in LUSC tissues. The combined standard mean difference (SMD) values of miR-198-5p expression based on GEO datasets were − 0.30 (95% confidence interval (CI) − 0.54, − 0.06) and − 0.39 (95% CI − 0.83, 0.05) using fixed effect model and random effect model, respectively. The sensitivity and specificity were not sufficiently high, as the area under the curve (AUC) was 0.7749 (Q* = 0.7143) based on summarized receiver operating characteristic (SROC) curves constructed using GEO datasets. Based on the in-house RT-qPCR, miR-198-5p expression was 4.3826 ± 1.7660 in LUSC tissues and 4.4522 ± 1.8263 in adjacent normal tissues (P = 0.885). The expression of miR-198-5p was significantly higher in patients with early TNM stages (I-II) than that in cases with advanced TNM stages (III-IV) (5.4400 ± 1.5277 vs 3.5690 ± 1.5228, P = 0.008). Continuous variable-based meta-analysis of GEO and PCR data displayed the SMD values of − 0.26 (95% CI − 0.48, − 0.04) and − 0.34 (95% CI − 0.71, 0.04) based on fixed and random effect models, respectively. As for the diagnostic value of miR-198-5p, the AUC based on the SROC curve using GEO and PCR data was 0.7351 (Q* = 0.6812). In total, 542 genes were identified as the targets of miR-198-5p. The most enriched Gene Ontology terms were epidermis development among biological processes, cell junction among cellular components, and protein dimerization activity among molecule functions. The pathway of non-small cell lung cancer was the most significant pathway identified using Kyoto Encyclopedia of Genes and Genomes analysis.

Conclusion

The expression of miR-198-5p is related to the TNM stage. Thus, miR-198-5p might play an important role via its target genes in LUSC.

The role of miRNAs in the diagnosis, chemoresistance, and prognosis of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains a very challenging malignancy with late presentation, metastatic potential, chemoresistance, and poor prognosis. Therefore, there is an urgent need for novel diagnostic and prognostic biomarkers. miRNAs are small noncoding RNAs that regulate the expression of multitude number of genes. Aberrant expression of miRNAs has been linked to the development of various malignancies, including PDAC. A series of miRNAs have been defined as holding promise for early diagnostics, as indicators of therapy resistance, and even as markers for prognosis in PDAC patients. In this review, we summarize the current knowledge on the role of miRNAs in diagnosis, chemoresistance, and prognosis in PDAC patients.

miR-21 expression and clinical outcome in locally advanced pancreatic cancer: exploratory analysis of the pancreatic cancer Erbitux, radiotherapy and UFT (PERU) trial

Background

Locally advanced pancreatic cancer (LAPC) is associated with high mortality, and biomarker-driven treatment approach is currently lacking. This study evaluated safety and efficacy of a combination approach of chemotherapy followed by chemo-radiotherapy (CRT) +/− cetuximab, and the prognostic role of miR-21 in patients with LAPC treated with a multimodality approach.

Patients and Methods

This was a randomised phase II trial in which patients with inoperable LAPC were offered gemcitabine and capecitabine (GEM-CAP) for 16 weeks. Patients with stable disease or response after GEM-CAP were randomised to capecitabine or UFT plus radiotherapy (RT) (A), or capecitabine or UFT plus cetuximab plus RT (B). The primary outcome of the study was overall survival (OS). Clinical outcome was compared according to baseline circulating miR-21 levels.

Results

17 patients were enrolled and treated with GEM-CAP, with 13 patients achieving disease control and being randomised to arms A (n:7) and B (n:6). After a median follow-up of 61.2 months, median progression free survival (PFS) was 10.4 months and 12.7 months, median OS was 15.8 months and 22.0 months in arms A and B respectively (p > 0.05). Patients with high baseline plasma miR-21 had worse PFS (3.5 vs. 12.7 months; p:0.032) and OS (5.1 vs 15.3 months; p:0.5) compared to patients with low miR-21. Circulating miR-21 levels reflected miR-21 expression within the tissues.

Conclusions

Addition of Cetuximab to CRT following induction chemotherapy did not improve survival. High miR-21 baseline plasma expression was associated with poor clinical outcome in LAPC patients treated with induction chemotherapy followed by chemo-radiotherapy.

Prognostic value of microRNA expression levels in pancreatic adenocarcinoma: a review of the literature

Background

Clinical and pathologic markers of prognosis and patterns of failure help guide clinicians in selecting patients for adjuvant therapy after surgical resection for pancreatic adenocarcinoma (PDAC). Recent studies have reported the prognostic utility of microRNA profiling in numerous malignancies. Here, we review and summarize the current literature regarding associations between microRNA expression and overall survival in PDAC patients.

Materials and Methods

We conducted a systematic search in the PubMed database to identify all primary research studies reporting prognostic associations between tumor and/or serum microRNA expression and overall survival in PDAC patients. Eligible articles were reviewed by the authors and relevant findings are summarized below.

Results

We found 53 publications that fit our search criteria. In total, 23 up-regulated and 49 down-regulated miRNAs have been associated with worse overall survival. MiR-21 is the most commonly reported miRNA, appearing in 19 publications, all of which report aberrant over-expression and association with shorter survival in PDAC. Other miRNAs that appear in multiple publications include miR-10b, −21, −34a, −155, −196a, −198, −200c, −203, −210, −218, −222, and −328. We summarize the preclinical and clinical data implicating these miRNAs in various molecular signaling pathways and cellular functions.

Conclusions

There is growing evidence that miRNA expression profiles have the potential to provide tumor-specific prognostic information to assist clinicians in more appropriately selecting patients for adjuvant therapy. These molecules are often aberrantly expressed and exhibit oncogenic and/or tumor suppressor functions in PDAC. Additional efforts to develop prognostic and predictive molecular signatures, and further elucidate miRNA mechanisms of action, are warranted.

MicroRNA-452 suppresses pancreatic cancer migration and invasion by directly targeting B-cell-specific Moloney murine leukemia virus insertion site 1

Pancreatic cancer, one of the most common cancers globally, is the fourth most common cause of cancer-associated mortality in the USA. The 5-year relative survival rate for patients with pancreatic cancer is ~5% and the median survival time is only 6 months. The poor prognosis is mainly due to early and aggressive local invasion and metastasis, as well as dissemination of the pancreatic cancer cells. The present study demonstrated that microRNA-452 (miR-452) was markedly downregulated in pancreatic cancer tissues, particularly in metastatic tumors and pancreatic cancer cell lines. Overexpression of miR-452 significantly inhibited migration and invasion in pancreatic cancer cells. In addition, the molecular mechanism underlying the inhibitory functions of miR-452 in pancreatic cancer was also investigated. The results indicated that B-cell-specific Moloney murine leukemia virus insertion site 1 (BMI1) was a direct target gene of miR-452 in pancreatic cancer. Overexpression of miR-452 inhibited the migration and invasion of pancreatic cancer, at least partially by knockdown of BMI1 expression. The results provided novel insight with potential therapeutic applications for the treatment of metastatic pancreatic cancer.

Identifying miRNA-mRNA regulation network of chronic pancreatitis based on the significant functional expression

BACKGROUND

The aim of this study was to explore the underlying molecular mechanism and potential molecular biomarkers of chronic pancreatitis (CP) and construct a miRNA-mRNA regulation network.

METHODS

To explore the involvement of miRNAs in CP, we downloaded the miRNA and mRNA expression profiles of CP patients and healthy controls and identified the differentially expressed miRNAs and genes. Functional analysis was conducted and significant pathways were utilized. Finally, the miRNA-mRNA regulation network of CP was constructed.

RESULTS

A total of 44 miRNA risk gene pathway relationships were identified, and a complex regulation network was constructed with 3 genes (ABL1, MYC, and ANAPC13) having the highest degree in affecting the network of CP. Importantly, 4 risk genes (NOTCH3, COX5A, THBS1, and KARS) and 1 risk miRNA (hsa-miR-324-5p) were identified with high prediction accuracy.

CONCLUSIONS

In conclusion, we analyzed miRNAs and mRNAs expression profiles in CP, 1 risk miRNA, and 4 risk genes were identified with high prediction accuracy as biomarkers of CP. Although further evaluation in clinical study is needed, our findings provide new insights into the pathogenesis of CP and may improve the diagnosis and therapy by identifying novel targets.

MicroRNA-21 as a prognostic biomarker in patients with pancreatic cancer - A systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review and meta-analysis is to summarize the current knowledge regarding microRNA-21 and to evaluate its prognostic impact in patients with pancreatic cancer.

METHODS

We conducted an electronic literature search to identify all published studies in PubMed/MEDLINE, Scopus and Google Scholar databases from 2000 until August 2016.

RESULTS

A total of 17 studies involving 1471 patients met the inclusion criteria for the quantitative synthesis. The microRNA-21 upregulation was significantly associated with poorer overall survival, disease-free survival, and progression-free survival. The subgroup analysis revealed that microRNA-21 overexpression has a significant higher prognostic value for patients who receive adjuvant chemotherapy. Increased microRNA-21 was associated with a statistically significant higher rate of metastatic lymph nodes and poorly differentiated tumors.

CONCLUSIONS

MicroRNA-21 upregulation in pancreatic cancer is associated with a significantly poorer overall survival, disease-free survival, and progression-free survival. MicroRNA-21 may be a useful prognostic biomarker, allowing stratification for chemotherapy administration, and being a component of precision medicine in patients with pancreatic cancer.

MicroRNA 217 inhibits cell proliferation and enhances chemosensitivity to doxorubicin in acute myeloid leukemia by targeting KRAS

Acute myeloid leukemia (AML) is a heterogeneous malignant disorder derived from the myeloid hematopoietic cells that accounts for ~80% of all adult acute leukemia. Numerous studies have shown that drug resistance not only exists against conventional chemotherapeutic drugs, but also limits the efficacy of new biological agents. Therefore, it is important to identify the mechanisms behind chemoresistance and seek therapeutic strategies to enhance efficacy in AML chemotherapy. MicroRNA (miR)-217 has been recognized as a tumor suppressor that is downregulated in various types of cancer, however the mechanisms behind the expression and function of miR-217 in AML have not yet been recognized. The expression of miR-217 was determined by quantitative polymerase chain reaction (qPCR). Following transfection with miR-217 mimics, an MTT assay, chemosensitivity assay, cell apoptosis assay and western blot analysis were performed in AML cell lines. Functional assays were also performed to explore the effects of endogenous Kirsten rat sarcoma viral oncogene homolog (KRAS) in AML. The results revealed that miR-217 was downregulated in patients with AML. Overexpression of miR-217 inhibited cellular proliferation and enhanced cell chemosensitivity to doxorubicin by the cell apoptosis pathway in AML cells. A dual-luciferase reporter assay demonstrated that KRAS was a direct target gene of miR-217 in vitro. qPCR and western blot analysis revealed that miR-217 negatively regulated KRAS protein expression, but had no impact on KRAS mRNA expression. Knockdown of KRAS expression markedly suppressed AML cellular proliferation, and enhanced cell chemosensitivity to doxorubicin via the cell apoptosis pathway. These findings indicate that miR-217 functions as a tumor suppressor in AML by directly targeting KRAS. Therefore, miR-217-based therapeutic strategies may provide a novel strategy for the enhancement of efficacy in the treatment of AML.

Overexpressions of miR-212 are associated with poor prognosis of patients with pancreatic ductal adenocarcinoma

BACKGROUND

The miR-212 was among the top differentially expressed miRNAs in pancreatic ductal adenocarcinoma (PDAC).

OBJECTIVE

The aim of this study was to investigate the expression of miR-212 in PDAC and evaluate its correlation with major clinicopathologic features and patients' survival.

METHODS

Fluorescence in situ hybridization (FISH) was adopted to examine miRNA expression in 45 pancreatic cancer and 20 normal pancreatic tissues. The relationship of miR-212 expression with clinicopathologic parameters and clinical outcome was evaluated.

RESULTS

miR-212 was confirmed to have significantly higher expression in PDAC compared with normal pancreatic tissues (51.1% vs 10%, p< 0.01). High expression of miR-212 was significantly associated with tumor size (p = 0.048) and tumor stage (p = 0.023). Moreover, in univariant analysis, patients with high expression of miR-212 demonstrate significantly poorer overall survival (p= 0.02).

CONCLUSIONS

High expression of miR-212 in PDAC is associated with shorter overall survival. It may be not only a potential prognostic marker, but also a possible therapeutic target in PDAC.

Plasma microRNA192 in combination with serum CA19-9 as non-invasive prognostic biomarker in periampullary carcinoma

In this study, circulating microRNAs (miRNAs) are being investigated as non-invasive biomarkers for early diagnosis and prognosis of human cancers. Since the prognosis for pancreatobiliary subtype of periampullary carcinoma is poor, we assessed the prognostic relevance of miRNAs in combination with CA19-9 as noninvasive biomarker in periampullary carcinoma. Circulating miRNAs in plasma and serum CA19-9 were evaluated in periampullary carcinoma patients (n = 109) undergoing Whipple's pancreaticoduodenectomy and in healthy volunteers (n = 92). Tumour tissues were subjected to staging and subtyping prior to determining differentially expressed miRNAs in them by quantitative real-time polymerase chain reaction (qRT-PCR). Statistical analysis involved correlation, receiver operating characteristic, logistic regression, survival analyses and Cox-proportional regression. Of the three differentially expressed circulating miRNA, miRNA192 was significantly increased both in circulation and in tumour tissue and correlated with tumour stage and aggressiveness (r = 0.96, P < 0.0001). Area under the curve of circulating miRNA192 + CA19-9 combination was 0.877 (95% confidence interval, 0.72 to 0.96) for stage III and 0.92 (95% confidence interval, 0.77 to 0.88) for tumour aggressiveness. The combination was associated with poor survival (median: 22 months, P = 0.0008) in stage III patients. Cox-proportional regression analysis revealed prognostic importance of combination of circulating miR192 and CA19-9 (HR = 1.005, P = 0.0001) in periampullary carcinoma. In conclusion, combination of circulating miRNA192 with serum CA19-9 is a better prognostic biomarker than CA19-9 alone.

miR-198 functions as a tumor suppressor in breast cancer by targeting CUB domain-containing protein 1

The molecular mechanisms underlying the dysregulation of microRNAs (miRs) have been previously documented in breast cancer. miR-198 has been reported to be deregulated in several human cancers. However, the detailed effects of miR-198 on breast cancer progression remain unclear. Using quantitative polymerase chain reaction analysis, we demonstrated in the present study that miR-198 was downregulated in breast cancer tissues and cell lines, and that downregulation of miR-198 was significantly correlated with lymph node metastasis. Functional studies revealed that miR-198 inhibited cell proliferation and migration and promoted cell adhesion in aggressive breast cancer cells in vitro. In addition, we observed that CUB domain-containing protein 1 (CDCP1) was a direct target of miR-198, and that knockdown of CDCP1 inhibited cell proliferation and migration, and promoted cell adhesion, which was similar to the effects of overexpression of miR-198. Taken together, we provide evidence to characterize the role of miR-198/CDCP1 interaction in breast cancer, which may be useful in breast cancer therapy.

miR-216 and miR-217 expression is reduced in transgenic mouse models of pancreatic adenocarcinoma, knockout of miR-216/miR-217 host gene is embryonic lethal

Mice harboring a G12D activating Kras mutation are among the most heavily studied models in the field of pancreatic adenocarcinoma (PDAC) research. miRNAs are differentially expressed in PDAC from patients and mouse models of PDAC. To better understand the relationship that Kras activation has on miRNA expression, we profiled the expression of 629 miRNAs in RNA isolated from the pancreas of control, young, and old P48^+/Cre;LSL-KRAS^G12D as well as PDX-1-Cre;LSL-KRAS^G12D mice. One hundred of the differentially expressed miRNAs had increased expression in the advanced disease (old) P48^+/Cre;LSL-KRAS^G12D compared to wild-type mice. Interestingly, the expression of three miRNAs, miR-216a, miR-216b, and miR-217, located within a ∼30-kbp region on 11qA3.3, decreased with age (and phenotype severity) in these mice. miR-216/-217 expression was also evaluated in another acinar-specific ELa-Kras^G12D mouse model and was downregulated as well. As miR-216/-217 are acinar enriched, reduced in human PDAC and target KRAS, we hypothesized that they may maintain acinar differentiation or represent tumor suppressive miRNAs. To test this hypothesis, we deleted a 27.9-kbp region of 11qA3.3 containing the miR-216/-217 host gene in the mouse's germ line. We report that germ line deletion of this cluster is embryonic lethal in the mouse. We estimate that lethality occurs shortly after E9.5. qPCR analysis of the miR-216b and miR-217 expression in the heterozygous animals showed no difference in expression, suggesting haplosufficiency by some type of compensatory mechanism. We present the differential miRNA expression in Kras^G12D transgenic mice and report lethality from deletion of the miR-216/-217 host gene in the mouse's germ line.

The miRacle in Pancreatic Cancer by miRNAs: Tiny Angels or Devils in Disease Progression

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with increasing incidence and high mortality. Surgical resection is the only potentially curative treatment of patients with PDAC. Because of the late presentation of the disease, about 20 percent of patients are candidates for this treatment. The average survival of resected patients is between 12 and 20 months, with a high probability of relapse. Standard chemo and radiation therapies do not offer significant improvement of the survival of these patients. Furthermore, novel treatment options aimed at targeting oncogenes or growth factors in pancreatic cancer have proved unsuccessful. Thereby, identifying new biomarkers that can detect early stages of this disease is of critical importance. Among these biomarkers, microRNAs (miRNAs) have supplied a profitable recourse and become an attractive focus of research in PDAC. MiRNAs regulate many genes involved in the development of PDAC through mRNA degradation or translation inhibition. The possibility of intervention in the molecular mechanisms of miRNAs regulation could begin a new generation of PDAC therapies. This review summarizes the reports describing miRNAs involvement in cellular processes involving pancreatic carcinogenesis and their utility in diagnosis, survival and therapeutic potential in pancreatic cancer.

Serum microRNA-196 and microRNA-200 in pancreatic ductal adenocarcinoma of patients with diabetes mellitus

BACKGROUND/OBJECTIVES

Our aim was to compare expressions of 6 microRNAs (miRNAs) in patients with pancreatic ductal adenocarcinoma (PAC) and non-cancer patients, moreover according to the presence or absence of diabetes mellitus.

METHODS

Expressions of miRNA-192, -196, -200, -21, -30 and -423 were measured in 77 patients with PAC and 64 non-cancer patients (34 patients with type 2 DM and 30 control persons). 60 patients with PAC (78%) had DM or prediabetes and it was of new-onset (less than 2 years before the cancer diagnosis) in 44 out of them.

RESULTS

The expressions of all microRNAs were 1.4-3.7 times higher (significantly) in the PAC group compared to non-cancer patients. No difference was found between PAC diabetic and PAC non-diabetic patients. MicroRNA-200 was significantly higher in PAC patients with significant body weight loss against those without weight loss. Adding miRNA-196 and -200 to the current marker CA 19-9 improved the discriminative ability of the test (compared to CA 19-9 alone).

CONCLUSION

MicroRNA-196 and -200 could be used as additional markers in PAC diagnosis.

MicroRNA-198 inhibited tumorous behaviors of human osteosarcoma through directly targeting ROCK1

Osteosarcoma is an aggressive primary sarcoma of bone and occurs mainly in adolescents and young adults. The prognosis of OS remains poor, and most of them will die due to local relapse or metastases. The discovery of microRNAs provides a new possibility for the early diagnosis and treatment of OS. Thus, the aim of this study was to explore the expression and functions of microRNA-198 (miR-198) in osteosarcoma. The expression levels of miR-198 were determined by qRT-PCR in osteosarcoma tissues and cell lines. Cell proliferation assays, migration and invasion assays were adopted to investigate the effects of miR-198 on tumorous behaviors of osteosarcoma cells. The results showed that miR-198 expression levels were lower in osteosarcoma tissues and cell lines. In addition, low miR-198 expression levels were correlated with TNM stage and distant metastasis. After miR-198 mimics transfection, cell proliferation, migration and invasion were significantly suppressed in the osteosarcoma cells. Furthermore, ROCK1 was identified as a novel direct target of miR-198 in osteosarcoma. These findings suggested that miR-198 may act not only as a novel prognostic marker, but also as a potential target for molecular therapy of osteosarcoma.