Real-time PCR-based analysis of the human bile microRNAome identifies miR-9 as a potential diagnostic biomarker for biliary tract cancer

Extracellular vesicles in liver diseases

Extracellular vesicles (EVs) are membrane-bound vesicles that are released by cells into their extracellular environment, have selective enrichment of specific proteins and RNA, and can mediate intercellular communication. In this review we highlight recent observations of the role of EVs in liver injury, viral hepatitis, alcoholic or nonalcoholic liver disease, biliary tract disease, and liver cancers. Potential applications as markers of diseases or for therapeutic applications are outlined to emphasize the new opportunities that are arising from the study of EVs.

The Emerging Role of miRNAs and Their Clinical Implication in Biliary Tract Cancer

Biliary tract cancers are aggressive malignancies that include gallbladder cancer and tumors of intra- and extrahepatic ducts and have a poor prognosis. Surgical resection remains the main curative therapy. Nevertheless, numerous patients experience recurrence even after radical surgery. This scenario drives the research to identify biliary tract cancer biomarkers despite the limited progress that has been made. Recently, a large number of studies have demonstrated that deregulated expression of microRNAs is closely associated with cancer development and progression. In this review, we highlight the role and importance of microRNAs in biliary tract cancers with an emphasis on utilizing circulating microRNAs as potential biomarkers. Additionally, we report several single-nucleotide polymorphisms in microRNA genes that are associated with the susceptibility of biliary tract tumors.

Deregulated MicroRNAs in Biliary Tract Cancer: Functional Targets and Potential Biomarkers

Biliary tract cancer (BTC) is still a fatal disease with very poor prognosis. The lack of reliable biomarkers for early diagnosis and of effective therapeutic targets is a major demanding problem in diagnosis and management of BTC. Due to the clinically silent and asymptomatic characteristics of the tumor, most patients are diagnosed at an already advanced stage allowing only for a palliative therapeutic approach. MicroRNAs are small noncoding RNAs well known to regulate various cellular functions and pathologic events including the formation and progression of cancer. Over the last years, several studies have shed light on the role of microRNAs in BTC, making them potentially attractive therapeutic targets and candidates as biomarkers. In this review, we will focus on the role of oncogenic and tumor suppressor microRNAs and their direct targets in BTC. Furthermore, we summarize and discuss data that evaluate the diagnostic power of deregulated microRNAs as possible future biomarkers for BTC.

Diagnostic value of microRNAs as biomarkers for cholangiocarcinoma

BACKGROUND

It has been reported that microRNAs might serve as biomarkers for cholangiocarcinoma (CCA) detection, but their diagnostic accuracy are unclear and controversial.

AIM

To evaluate the diagnostic accuracy of microRNAs for CCA.

MATERIALS AND METHODS

PubMed, Embase, Web of Science and Cochrane Library were systematically searched to identify relevant articles by using the key words "cholangiocarcinoma" and "microRNA". The methodological quality of each study was assessed by QUADAS-2. According to the inclusive and exclusive criteria, 11 articles were identified and analyzed by Meta-disc software v.1.4 and STATA 12.0 software package.

RESULTS

11 articles with 430 CCA patients and 406 controls were identified. The results showed that the pooled sensitivity was 0.756 (95% CI: 0.693-0.810), specificity was 0.914 (95% CI: 0.861-0.947), positive likelihood ratio was 8.747 (95% CI: 5.320-14.381), negative likelihood ratio was 0.267 (95% CI: 0.208-0.341) and diagnostic odds ratio was 32.791 (95% CI: 17.327, 62.060). In addition, the area under the summary ROC cure (AUC) was 0.90 (95% CI: 0.87-0.93).

CONCLUSION

MicroRNAs have great potential as biomarkers for the diagnosis of CCA patients. However, the clinical application of microRNA assays for CCA diagnosis still needs further validation by more prospective studies.

Are circulating microRNAs peripheral biomarkers for Alzheimer's disease?

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by memory loss, multiple cognitive abnormalities and intellectual impairments. Currently, there are no drugs or agents that can delay and/or prevent the progression of disease in elderly individuals, and there are no peripheral biomarkers that can detect AD early in its pathogenesis. Research has focused on identifying biomarkers for AD so that treatment can be begun as soon as possible in order to restrict or prevent intellectual impairments, memory loss, and other cognitive abnormalities that are associated with the disease. One such potential biomarker is microRNAs that are found in circulatory biofluids, such as blood and blood components, serum and plasma. Blood and blood components are primary sources where miRNAs are released in either cell-free form and then bind to protein components, or are in an encapsulated form with microvesicle particles. Exosomal miRNAs are known to be stable in biofluids and can be detected by high throughput techniques, like microarray and RNA sequencing. In AD brain, enriched miRNAs encapsulated with exosomes crosses the blood brain barrier and secreted in the CSF and blood circulations. This review summarizes recent studies that have identified miRNAs in the blood, serum, plasma, exosomes, cerebral spinal fluids, and extracellular fluids as potential biomarkers of AD. Recent research has revealed only six miRNAs - miR-9, miR-125b, miR-146a, miR-181c, let-7g-5p, and miR-191-5p - that were reported by multiple investigators. Some studies analyzed the diagnostic potential of these six miRNAs through receiver operating curve analysis which indicates the significant area-under-curve values in different biofluid samples. miR-191-5p was found to have the maximum area-under-curve value (0.95) only in plasma and serum samples while smaller area-under-curve values were found for miR-125, miR-181c, miR-191-5p, miR-146a, and miR-9. This article shortlisted the promising miRNA candidates and discussed their diagnostic properties and cellular functions in order to search for potential biomarker for AD.

Polarized release of hepatic microRNAs into bile and serum in response to cellular injury and impaired liver function

BACKGROUND & AIMS

Extracellular microRNAs (miRNAs) in serum and bile are currently under intense investigation for biomarker purposes in liver disease. However, the directions and pathways by which miRNAs are released from hepatic cells remains largely unknown. Here, we investigated the release of hepatocyte and cholangiocyte-derived miRNAs (HDmiRs and CDmiRs) into blood and bile during various (patho)physiological hepatic conditions.

METHODS

MiRNA release was analysed using longitudinally collected tissue and paired bile and serum samples (n = 124) that were obtained from liver transplant recipients during follow-up.

RESULTS

Cell-type specificity of HDmiRs and CDmiRs was confirmed in liver and common bile duct biopsies (P < 0.001). Analysis of paired bile and serum samples showed up to 20-times higher miRNA-levels in bile compared to serum (P < 0.0001). Fractionation of bile showed the majority of miRNAs being present in the unpelletable supernatant, where protein conjunctions protect miRNAs against degradation (P < 0.0001). During episodes of liver injury and histologically proven rejection in liver transplant recipients, relative HDmiR-levels in bile decreased while its levels in serum increased (P ≤ 0.015). Simultaneously, relative CDmiR-levels in bile significantly increased, while their levels in serum decreased. Related to liver excretory function, a strong positive correlation was observed between HDmiR-122 levels and bilirubin excretion into bile (R = 0.694, P < 0.0001), whereas CDmiRs showed an inverse correlation (P < 0.05).

CONCLUSION

During impaired excretory function and injury, the liver shows polarized release of extracellular HDmiRs and CDmiRs. This sheds new light on the biology of hepatic miRNA release which is relevant for the interpretation of hepatic miRNAs as biomarkers.

Circulating MicroRNAs as Biomarkers in Biliary Tract Cancers

Biliary tract cancers (BTCs) are a group of highly aggressive malignant tumors with a poor prognosis. The current diagnosis is based mainly on imaging and intraoperative exploration due to brush cytology havinga low sensitivity and the standard markers, such as carcinoembryonic antigen (CEA) and carbohydrate 19-9 (CA19-9), not having enough sensitivity nor specificity to be used in a differential diagnosis and early stage detection. Thus, better non-invasive methods that can distinguish between normal and pathological tissue are needed. MicroRNAs (miRNAs) are small, single-stranded non-coding RNA molecules of ~20–22 nucleotides that regulate relevant physiological mechanisms and can also be involved in carcinogenesis. Recent studies have demonstrated that miRNAs are detectable in multiple body fluids, showing great stability, either free or trapped in circulating microvesicles, such as exosomes. miRNAs are ideal biomarkers that may be used in screening and prognosis in biliary tract cancers, aiding also in the clinical decisions at different stages of cancer treatment. This review highlights the progress in the analysis of circulating miRNAs in serum, plasma and bile as potential diagnostic and prognostic markers of BTCs.

Lin28 and let-7: roles and regulation in liver diseases

The diagnosis and treatment of liver disease remain a major health concern worldwide because of the diverse etiologies of this disease. For this reason, new therapeutic targets are greatly needed to halt the progression of this damaging disease. Upon initiation of liver injury by viral infection, autoimmune disease or toxin, and/or hepatitis, chronic disease may develop, which can progress to cirrhosis, hepatocellular carcinoma (HCC), cholangiocarcinoma, liver failure, or death. The Lin28/lethal-7 (let-7) molecular switch has emerged as a central regulator of multiorgan injuries and cancer development. Lin28 is a stem cell marker vital to initiation or maintenance of a stem cell phenotype. Lin28 has not been extensively studied in the liver, despite its ability to induce tissue regeneration via reprogramming of oxidative enzymes in other tissues and its involvement with numerous upstream regulators and downstream targets in liver disease. Theoretically, overexpression of Lin28 in certain forms of liver disease could be a potential treatment that aids in liver regeneration. Alternatively, Lin28 has been implicated numerous times in the progression of diverse cancer types and is associated with increased severity of disease. In this case, Lin28 could be a potential inhibitory target to prevent malignant transformation in the liver. This review seeks to characterize the role of Lin28 in liver disease.

Circulating microRNAs as Potential Biomarkers in Non-Alcoholic Fatty Liver Disease and Hepatocellular Carcinoma

Obesity and metabolic syndrome are growing epidemics worldwide and greatly responsible for many liver diseases, including nonalcoholic fatty liver disease (NAFLD). NAFLD often progresses to cirrhosis, end-stage liver failure and hepatocellular carcinoma (HCC), the most common primary liver cancer and one of the leading causes for cancer-related deaths globally. Currently available tools for the diagnosis of NAFLD staging and progression towards HCC are largely invasive and of limited accuracy. In light of the need for more specific and sensitive noninvasive molecular markers, several studies have assessed the potential of circulating microRNAs (miRNAs) as biomarkers of liver injury and hepatocarcinogenesis. Indeed, extracellular miRNAs are very stable in the blood, can be easily quantitated and are differentially expressed in response to different pathophysiological conditions. Although standardization procedures and larger, independent studies are still necessary, miRNAs constitute promising, clinically-useful biomarkers for the NAFLD-HCC spectrum.

Cholangiocarcinoma: Current opinion on clinical practice diagnostic and therapeutic algorithms: A review of the literature and a long-standing experience of a referral center

In the oncology landscape, cholangiocarcinoma is a challenging disease in terms of both diagnosis and treatment. Besides anamnesis and clinical examination, a definitive diagnosis of cholangiocarcinoma should be supported by imaging techniques (US, CT, MRI) and invasive investigations (ERC or EUS with brushing and FNA or US or CT-guided biopsy) followed by pathological confirmation. Surgery is the main curative option, so resectability of the tumour should be promptly assessed. Moreover, jaundice must be evaluated at the outset because biliary tract decompression with drainage and stent placement may be required. If the patient is resectable, pre-operative assessment of postoperative liver function is mandatory. After a curative resection, an adjuvant therapy may be administered. Otherwise, in cases with macroscopic residual disease after surgery or locally recurrent or unresectable cholangiocarcinoma at the diagnosis, first-line chemotherapy is the preferred strategy, possibly associated with radiotherapy and/or locoregional treatments. As the diagnostic and therapeutic pathway for cholangiocarcinoma can be declined in different modalities, patients should be promptly referred to a multidisciplinary team in a tertiary centre, familiar with this rare but lethal disease. Hence, the aim of the present paper is to focus on diagnostic and therapeutic algorithms based on the common guidelines and also on the clinical practice of multispecialist expert groups.

MicroRNAs in cholangiopathies: Potential diagnostic and therapeutic tools

Cholangiopathies are the group of diseases targeting the bile duct epithelial cells (i.e. cholangiocytes). These disorders arise from different etiologies and represent a current diagnostic, prognostic and therapeutic challenge. Different molecular mechanisms participate in the development and progression of each type of biliary disease. However, microRNA deregulation is a common central event occurring in all of them that plays a key role in their pathogenesis. MicroRNAs are highly stable small non-coding RNAs present in cells, extracellular microvesicles and biofluids, representing valuable diagnostic tools and potential targets for therapy. In the following sections, the most novel and significant discoveries in this field are summarized and their potential clinical value is highlighted.

MicroRNA expression profiles differentiate chronic pain condition subtypes

Chronic pain is a significant health care problem, ineffectively treated because of its unclear etiology and heterogeneous clinical presentation. Emerging evidence demonstrates that microRNAs (miRNAs) regulate the expression of pain-relevant genes, yet little is known about their role in chronic pain. Here, we evaluate the relationship among pain, psychological characteristics, plasma cytokines, and whole blood miRNAs in 22 healthy controls (HCs); 33 subjects with chronic pelvic pain (vestibulodynia, VBD); and 23 subjects with VBD and irritable bowel syndrome (VBD + IBS). VBD subjects were similar to HCs in self-reported pain, psychological profiles, and remote bodily pain. VBD + IBS subjects reported decreased health and function; and an increase in headaches, somatization, and remote bodily pain. Furthermore, VBD subjects exhibited a balance in proinflammatory and anti-inflammatory cytokines, whereas VBD + IBS subjects failed to exhibit a compensatory increase in anti-inflammatory cytokines. VBD subjects differed from controls in expression of 10 miRNAs of predicted importance for pain and estrogen signaling. VBD + IBS subjects differed from controls in expression of 11 miRNAs of predicted importance for pain, cell physiology, and insulin signaling. miRNA expression was correlated with pain-relevant phenotypes and cytokine levels. These results suggest that miRNAs represent a valuable tool for differentiating VBD subtypes (localized pain with apparent peripheral neurosensory disruption vs widespread pain with a central sensory contribution) that may require different treatment approaches.

Primary Sclerosing Cholangitis as a Premalignant Biliary Tract Disease: Surveillance and Management

Primary sclerosing cholangitis (PSC) is a premalignant biliary tract disease that confers a significant risk for the development of cholangiocarcinoma (CCA). The chronic biliary tract inflammation of PSC promotes pro-oncogenic processes such as cellular proliferation, induction of DNA damage, alterations of the extracellular matrix, and cholestasis. The diagnosis of malignancy in PSC can be challenging because inflammation-related changes in PSC may produce dominant biliary tract strictures mimicking CCA. Biomarkers such as detection of methylated genes in biliary specimens represent noninvasive techniques that may discriminate malignant biliary ductal changes from PSC strictures. However, conventional cytology and advanced cytologic techniques such as fluorescence in situ hybridization for polysomy remain the practice standard for diagnosing CCA in PSC. Curative treatment options of malignancy arising in PSC are limited. For a subset of patients selected by using stringent criteria, liver transplantation after neoadjuvant chemoradiation is a potential curative therapy. However, most patients have advanced malignancy at the time of diagnosis. Advances directed at identifying high-risk patients, early cancer detection, and development of chemopreventive strategies will be essential to better manage the cancer risk in this premalignant disease. A better understanding of dysplasia definition and especially its natural history is also needed in this disease. Herein, we review recent developments in our understanding of the risk factors, pathogenic mechanisms of PSC associated with CCA, as well as advances in early detection and therapies.

MicroRNAs in Serum and Bile of Patients with Primary Sclerosing Cholangitis and/or Cholangiocarcinoma

BACKGROUND AND AIM

Patients with primary sclerosing cholangitis (PSC) are at high risk for the development of cholangiocarcinoma (CC). Analysis of micro ribonucleic acid (MiRNA) patterns is an evolving research field in biliary pathophysiology with potential value in diagnosis and therapy. Our aim was to evaluate miRNA patterns in serum and bile of patients with PSC and/or CC.

METHODS

Serum and bile from consecutive patients with PSC (n = 40 (serum), n = 52 (bile)), CC (n = 31 (serum), n = 19 (bile)) and patients with CC complicating PSC (PSC/CC) (n = 12 (bile)) were analyzed in a cross-sectional study between 2009 and 2012. As additional control serum samples from healthy individuals were analyzed (n = 12). The miRNA levels in serum and bile were determined with global miRNA profiling and subsequent miRNA-specific polymerase chain reaction-mediated validation.

RESULTS

Serum analysis revealed significant differences for miR-1281 (p = 0.001), miR-126 (p = 0.001), miR-26a (p = 0.001), miR-30b (p = 0.001) and miR-122 (p = 0.034) between patients with PSC and patients with CC. All validated miRNAs were significantly lower in healthy individuals. MiR-412 (p = 0.001), miR-640 (p = 0.001), miR-1537 (p = 0.003) and miR-3189 (p = 0.001) were significantly different between patients with PSC and PSC/CC in bile.

CONCLUSIONS

Patients with PSC and/or CC have distinct miRNA profiles in serum and bile. Furthermore, miRNA concentrations are different in bile of patients with CC on top of PSC indicating the potential diagnostic value of these miRNAs.

Determination of the potential bioavailability of plant microRNAs using a simulated human digestion process

SCOPE

The "dietary xenomiR hypothesis" proposes that microRNAs (miRNAs) in foodstuffs survive transit through the mammalian gastrointestinal tract and pass into cells intact to affect gene regulation. However, debate continues as to whether dietary intake poses a feasible route for such exogenous gene regulators. Understanding on miRNA levels during pretreatments of human diet is essential to test their bioavailability during digestion. This study makes the novel first use of an in vitro method to eliminate the inherent complexities and variability of in vivo approaches used to test this hypothesis.

METHODS AND RESULTS

Plant miRNA levels in soybean and rice were measured during storage, processing, cooking, and early digestion using real-time PCR. We have demonstrated for the first time that storage, processing, and cooking does not abolish the plant miRNAs present in the foodstuffs. In addition, utilizing a simulated human digestion system revealed significant plant miRNA bioavailability after early stage digestion for 75 min. Attenuation of plant messenger RNA and synthetic miRNA was observed under these conditions.

CONCLUSION

Even after an extensive pretreatment, plant-derived miRNA, delivered by typical dietary ingestion, has a robustness that could make them bioavailable for uptake during early digestion. The potential benefit of these regulatory molecules in pharma nutrition could be explored further.

MicroRNAs in the Cholangiopathies: Pathogenesis, Diagnosis, and Treatment

The cholangiopathies are a group of liver diseases resulting from different etiologies but with the cholangiocyte as the primary target. As a group, the cholangiopathies result in significant morbidity and mortality and represent one of the main indications for liver transplant in both children and adults. Contributing to this situation is the absence of a thorough understanding of their pathogenesis and a lack of adequate diagnostic and prognostic biomarkers. MicroRNAs are small non-coding RNAs that modify gene expression post-transcriptionally. They have been implicated in the pathogenesis of many diseases, including the cholangiopathies. Thus, in this review we provide an overview of the literature on miRNAs in the cholangiopathies and discuss future research directions.

Genetic alteration regulated by microRNAs in biliary tract cancers

Biliary tract cancers (BTCs) constitute a relatively rare but highly malignant class of tumors with poor prognosis including gallbladder cancer, intra- and extra-hepatic cholangiocarcinoma. Recently, accumulated evidences have demonstrated that deregulated expression of microRNAs (miRNAs) is closely associated with the development, invasion, metastasis and prognosis of different cancers including BTCs. MiRNAs comprise an endogenously expressed and highly evolutionarily conserved group of small, non-coding, single-stranded RNAs which negatively regulate target genes expression by means of combining with 3' untranslated region (UTR) of corresponding mRNAs at the post-transcriptional level with significant roles in various fundamental cellular procedures including cell proliferation, differentiation, migration, cell cycle control and apoptosis. Recent studies have indicated that miRNAs could function as novel tumor-promoting genes or tumor suppressor genes to act as potential therapeutic targets in anticancer treatment because the genetic alteration regulated by miRNAs could result in tumorigenesis and tumor inhibition. Anomalous miRNAs expression patterns, acting as phenotypic signatures of distinct cancers, are promising to be used as diagnostic, prognostic, predictive biomarkers. In this review, we summarize the current findings from the studies about potential genetic alteration regulated by miRNAs and their roles in BTCs.

MicroRNAs in mesenteric lymph and plasma during acute pancreatitis

OBJECTIVE

To isolate microRNAs (miRNAs) from mesenteric lymph (ML) and peripheral blood and identify those that change with experimental acute pancreatitis (AP). To assess identified AP-associated miRNAs in patient plasma to evaluate them as clinical biomarkers of AP.

BACKGROUND

miRNAs, small non-protein-coding molecules that regulate gene expression, are present in many biological fluids. They are increasingly interesting as biomarkers of disease and as novel signaling molecules in pathogenesis.

METHODS

Affymetrix miRNA profiling was performed on ML collected from 3 groups of rats with either mild or moderate taurocholate-induced AP and sham controls. Quantitative reverse transcription-polymerase chain reaction was used to validate selected miRNAs in matched rat lymph and plasma and then measured in patients with mild or moderate AP and in healthy volunteers.

RESULTS

Eighty-five miRNAs were detectable in rat ML, and many were abundant in all animals irrespective of the presence of AP. Seven miRNAs, comprising miR-375, -217, -148a, -216a, -122, -214, and -138, were increased in ML from rats with AP (P < 0.01). Their abundance also altered with disease severity. miRNAs miR-217, -375, -122, and -148a were also increased in matched rat plasma samples by quantitative reverse transcription-polymerase chain reaction. In the clinical studies, plasma miR-216a was significantly increased in both mild and moderate AP.

CONCLUSIONS

This study is the first to demonstrate both the presence of circulating miRNAs in lymph and the alteration of specific miRNAs in AP. Furthermore, these miRNAs alter in rat and human AP plasma and have potential to be explored as novel biomarkers of pancreatitis.

MicroRNAs in alcoholic liver disease

Alcoholic liver disease (ALD) is characterized by hepatocyte damage, inflammatory cell activation and increased intestinal permeability leading to the clinical manifestations of alcoholic hepatitis. Selected members of the family of microRNAs are affected by alcohol, resulting in an abnormal miRNA profile in the liver and circulation in ALD. Increasing evidence suggests that mRNAs that regulate inflammation, lipid metabolism and promote cancer are affected by excessive alcohol administration in mouse models of ALD. This communication highlights recent findings in miRNA expression and functions as they relate to the pathogenesis of ALD. The cell-specific distribution of miRNAs, as well as the significance of circulating extracellular miRNAs, is discussed as potential biomarkers. Finally, the prospects of miRNA-based therapies are evaluated in ALD.

MicroRNAs and benign biliary tract diseases

Cholangiocytes, the epithelial cells lining the biliary tree, represent only a small portion of the total liver cell population (3-5%), but they are responsible for the secretion of up to 40% of total daily bile volume. In addition, cholangiocytes are the target of a diverse group of liver diseases affecting the biliary tract, the cholangiopathies; for most of these conditions, the pathological mechanisms are unclear. MicroRNAs (miRNAs) are small, noncoding RNAs that posttranscriptionally regulate gene expression. Thus, it is not surprising that altered miRNA profiles underlie the dysregulation of several proteins involved in the pathobiology of the cholangiopathies, as well as showing promise as diagnostic and prognostic tools. Here the authors review recent work relevant to the role of miRNAs in the etiopathogenesis of several of the cholangiopathies (i.e., fibroinflammatory cholangiopathies and polycystic liver diseases), discuss their value as prognostic and diagnostic tools, and provide suggestions for further research.

MicroRNAs in alcoholic liver disease

Alcoholic liver disease (ALD) is characterized by hepatocyte damage, inflammatory cell activation and increased intestinal permeability leading to the clinical manifestations of alcoholic hepatitis. Selected members of the family of microRNAs are affected by alcohol, resulting in an abnormal miRNA profile in the liver and circulation in ALD. Increasing evidence suggests that mRNAs that regulate inflammation, lipid metabolism and promote cancer are affected by excessive alcohol administration in mouse models of ALD. This communication highlights recent findings in miRNA expression and functions as they relate to the pathogenesis of ALD. The cell-specific distribution of miRNAs, as well as the significance of circulating extracellular miRNAs, is discussed as potential biomarkers. Finally, the prospects of miRNA-based therapies are evaluated in ALD.

Diagnostic Relevance of microRNAs in Other Body Fluids Including Urine, Feces, and Saliva

Beside blood-borne circulating miRNAs, miRNAs have been identified in other body fluid and excrements including stool, bile, saliva, and urine. Given the direct link of these body fluids to certain organs, their analysis for potential diagnostic miRNA markers is plausible. Several independent findings underline the potential utility of stool-derived miRNAs in the diagnosis of colorectal and pancreatic cancer. Given the difficulties in the diagnosis of cholangiocellular cancer, biliary miRNAs might be envisaged as useful markers. Several miRNAs have been identified in the saliva that could be associated with diseases, including tumors of the oral cavity. The urinary pool of miRNAs could be exploited for the diagnosis of urinary tract diseases and some appear to enable early diagnosis. In this chapter, we present findings supporting the potential diagnostic utility of fecal, biliary, salivary, and urinary miRNAs focusing mostly on tumors.

MicroRNA-9 as a novel prognostic biomarker in human laryngeal squamous cell carcinoma

In the present study, we aimed to detect microRNA-9 (miR-9) expression level and its clinical significance in laryngeal squamous cell carcinomas (LSCC). 103 patients who were diagnosed with LSCC and treated between March 2010 and June 2013 were enrolled in this study. Expression levels of miR-9 were detected by real-time quantitative RT-PCR assay. Survival curves were estimated using the Kaplan-Meier method, and differences between them were evaluated by the log-rank test. Cox proportional hazard regression test was used to estimate univariate and multivariate hazard ratios for prognosis. We found that miR-9 levels were significantly higher in LSCC tissues compared with matched non-cancerous tissues [4.55 (164-6.75) vs. 2.07 (0.89-2.65), P < 0.05]. The level of miR-9 in LSCC was strongly correlated with tumor differentiation (P = 0.031), thyroid cartilage invasion (P = 0.024), lymph node metastasis (P = 0.009) and clinical TNM stage (P = 0.011). The log-rank test showed that the survival time was significantly different between groups with high and low expression of miR-9 (Log Rank test, P = 0.014). Furthermore, Cox regression multivariate analysis demonstrated that miR-9 expression was an independent prognostic factor of outcomes in patients with LSCC after tumour resection (HR = 3.18, 95% CI = 2.19-11.91, P = 0.012). In conclusion, miR-9 expression was up-regulated in LSCC and was significantly associated with the progression and poorer prognosis of LSCC. Therefore, it might be utilized as a useful prognostic biomarker for LSCC.

MicroRNA-145 as ideal biomarker for the diagnosis of various carcinomas

Increasing evidences indicated that microRNAs (miRNAs) can serve as a noninvasive biomarker with a high sensitivity and specificity for the early diagnosis of various cancers, among which, microRNA-145 (miRNA-145, miR-145) was verified to have strong relationship to irregular apoptosis, thus making it useful in the early detection of cancers. However, contradictory results on its diagnostic accuracy and reliability are still existed in individual studies. Therefore, we conducted this meta-analysis of the relevant published literatures to systematically evaluate the diagnostic value of miR-145 in the prediction of cancers. The sensitivity and specificity of the included studies were used to construct the summary receiver operator characteristic (SROC) curve and calculate the area under the SROC curve (AUC). All analyses were performed using the STATA 12.0 software. Thirteen studies from nine articles were involved in our meta-analysis. The pooled parameters calculated from all studies are as follows: sensitivity, 0.71 (95% confidence interval (CI) 0.59-0.81); specificity, 0.75 (95% CI 0.66-0.83); positive likelihood ratio (PLR), 2.9 (95% CI 1.9-4.4); negative likelihood ratio (NLR), 0.38 (95% CI 0.25-0.58); and diagnostic odds ratio (DOR), 8 (95% CI 3-17). In addition, subgroup analyses based on ethnicity suggested that miR-145 as a biomarker on the detection of cancers for Caucasian population showed a higher sensitivity and specificity than for Asian population. In conclusion, the current meta-analysis showed that miR-145 holds a high accuracy in distinguishing cancer patients from healthy controls with noninvasiveness and high efficiency. However, large-scale prospective studies and additional improvements are urgently needed to confirm our findings and its utilization for routine clinical diagnosis in future.

MicroRNA-145: a potent tumour suppressor that regulates multiple cellular pathways

MicroRNAs are endogenous, small (18-25 nucleotides) non-coding RNAs, which regulate genes expression by directly binding to the 3'-untranslated regions of the target messenger RNAs. Emerging evidence shows that alteration of microRNAs is involved in cancer development. MicroRNA-145 is commonly down-regulated in many types of cancer, regulating various cellular processes, such as the cell cycle, proliferation, apoptosis and invasion, by targeting multiple oncogenes. This review aims to summarize the recent published literature on the role of microRNA-145 in regulating tumourigenesis and progression, and explore its potential for cancer diagnosis, prognosis and treatment.

The ins and outs of microRNAs as biomarkers in liver disease and transplantation

Ongoing research is being conducted in the field of transplantation to discover novel, noninvasive biomarkers for assessment of graft quality before transplantation and monitoring of graft injury after transplantation. MicroRNAs (miRNAs) are among the most promising in this field. MiRNAs are small noncoding RNAs that function as important regulators of gene expression in response to cellular stress and disease. An advantage that makes miRNAs attractive candidates for biomarker research is their fast release from cells in response to stress and injury, which can occur via different routes. In the context of liver transplantation (LT), noninvasive measurement and stability of extracellular miRNAs in blood, bile, and graft perfusates has been linked to cell-type specific injury and early graft outcome following LT. Furthermore, specific intrahepatic miRNA expression patterns have been associated with graft survival and recurrent disease, like hepatitis C virus-related fibrosis and hepatocellular carcinoma. Therefore, miRNAs with strong predictive value and high sensitivity and specificity might be successfully applied to assess hepatic injury and to diagnose (recurrent) liver disease before, during and after LT. In this review, the current features and future prospects of miRNAs as biomarkers in and out of the liver are discussed.

Comparative secretome analysis of cholangiocarcinoma cell line in three-dimensional culture

Cholangiocarcinoma (CCA) is a lethal malignancy which occurs with relatively high incidence in Thailand. This cancer is often difficult to diagnose and associated with high mortality. The secretome, containing the secreted proteins from cells, are potentially useful as biomarkers of cancers. Since three-dimensional (3D) cell culture may mimic growth characteristics and microenvironment of solid tumors in vivo better than monolayer culture, we have developed culture of CCA in natural collagen-based scaffold, to enable analysis of the secretome by 2DE. Our results indicated that CCA growth in 3D environment alters cell shape significantly and enhances extracellular matrix deposition. Interestingly, more secreted proteins were detected from 3D culture compared to monolayer culture. Secretome analysis using 2DE coupled with LC-MS/MS demonstrated 10 secreted proteins uniquely found in 3D culture. Moreover, 25 proteins were enriched in 3D culture compared to monolayer culture, including 14-3-3 σ, triosephosphate isomerase, phosphoglycerate mutase 1, α-enolase, and L-plastin. Immunoblotting was used to confirm the presence of L-plastin in conditioned media of CCA and of hepatocellular carcinoma (HCC) cell lines. The results revealed that L-plastin, an actin bundling protein, was uniquely expressed only in the CCA cell line and could be a promising biomarker for differential diagnosis of CCA compared to HCC.

Biomarkers to assess graft quality during conventional and machine preservation in liver transplantation

A global rising organ shortage necessitates the use of extended criteria donors (ECD) for liver transplantation (LT). However, poor preservation and extensive ischemic injury of ECD grafts have been recognized as important factors associated with primary non-function, early allograft dysfunction, and biliary complications after LT. In order to prevent for these ischemia-related complications, machine perfusion (MP) has gained interest as a technique to optimize preservation of grafts and to provide the opportunity to assess graft quality by screening for extensive ischemic injury. For this purpose, however, objective surrogate biomarkers are required which can be easily determined at time of graft preservation and the various techniques of MP. This review provides an overview and evaluation of biomarkers that have been investigated for the assessment of graft quality and viability testing during different types of MP. Moreover, studies regarding conventional graft preservation by static cold storage (SCS) were screened to identify biomarkers that correlated with either allograft dysfunction or biliary complications after LT and which could potentially be applied as predictive markers during MP. The pros and cons of the different biomaterials that are available for biomarker research during graft preservation are discussed, accompanied with suggestions for future research. Though many studies are currently still in the experimental setting or of low evidence level due to small cohort sizes, the biomarkers presented in this review provide a useful handle to monitor recovery of ECD grafts during clinical MP in the near future.

MicroRNAs in Cholangiopathies

Cholangiocytes, the cells lining bile ducts, comprise a small fraction of the total cellular component of the liver, yet perform the essential role of bile modification and transport of biliary and blood constituents. Cholangiopathies are a diverse group of biliary disorders with the cholangiocyte as the target cell; the etiopathogenesis of most cholangiopathies remains obscure. MicroRNAs are small non-coding RNAs that post-transcriptionally regulate gene expression. These small RNAs may not only be involved in the etiopathogenesis of disease, but are showing promise as diagnostic and prognostic tools. In this brief review, we summarize recent work regarding the role of microRNAs in the etiopathogenesis of several cholangiopathies, and discuss their utility as prognostic and diagnostic tools.

Human bile contains microRNA-laden extracellular vesicles that can be used for cholangiocarcinoma diagnosis

Cholangiocarcinoma (CCA) presents significant diagnostic challenges, resulting in late patient diagnosis and poor survival rates. Primary sclerosing cholangitis (PSC) patients pose a particularly difficult clinical dilemma because they harbor chronic biliary strictures that are difficult to distinguish from CCA. MicroRNAs (miRs) have recently emerged as a valuable class of diagnostic markers; however, thus far, neither extracellular vesicles (EVs) nor miRs within EVs have been investigated in human bile. We aimed to comprehensively characterize human biliary EVs, including their miR content. We have established the presence of extracellular vesicles in human bile. In addition, we have demonstrated that human biliary EVs contain abundant miR species, which are stable and therefore amenable to the development of disease marker panels. Furthermore, we have characterized the protein content, size, numbers, and size distribution of human biliary EVs. Utilizing multivariate organization of combinatorial alterations (MOCA), we defined a novel biliary vesicle miR-based panel for CCA diagnosis that demonstrated a sensitivity of 67% and specificity of 96%. Importantly, our control group contained 13 PSC patients, 16 with biliary obstruction of varying etiologies (including benign biliary stricture, papillary stenosis, choledocholithiasis, extrinsic compression from pancreatic cysts, and cholangitis), and 3 with bile leak syndromes. Clinically, these types of patients present with a biliary obstructive clinical picture that could be confused with CCA.

CONCLUSION

These findings establish the importance of using extracellular vesicles, rather than whole bile, for developing miR-based disease markers in bile. Finally, we report on the development of a novel bile-based CCA diagnostic panel that is stable, reproducible, and has potential clinical utility.

MiR-302c inhibits tumor growth of hepatocellular carcinoma by suppressing the endothelial-mesenchymal transition of endothelial cells

Endothelial cells (ECs) are critical for angiogenesis, and microRNA plays important roles in this process. In this study, we investigated the function and mechanism of miR-302c in the process of endothelial-mesenchymal transition (EndMT) in ECs. When miR-302c was overexpressed in HUVECs, the motility of the HUVECs was weakened; the expression levels of EndMT markers were also changed: vascular endothelial (VE)-cadherin was up-regulated, whereas β-catenin, FSP1, and α-SMA were down-regulated. Further in vivo and in vitro experiments showed that the growth of HCC was inhibited when co-cultured or co-injected with HUVECs overexpressing miR-302c. On the contrary, when miR-302c was suppressed in HUVECs, the opposite results were observed. Reporter assays showed that miR-302c inhibited metadherin (MTDH) expression through directly binding to its 3'UTR. In addition, compared to ECs isolated from normal liver tissues of HCC patients, ECs isolated from tumor tissues expressed markedly low levels of miR-302c but high levels of MTDH. These results suggest that EC-specific miR-302c suppresses tumor growth in HCC through MTDH-mediated inhibition of EndMT. MTDH and miR-302c might provide a new strategy for anti-angiogenic therapy in HCC.

MicroRNA-9 expression is a prognostic biomarker in patients with osteosarcoma

BACKGROUND

The purpose of the present study was to examine the expression levels of microRNA-9 (miR-9) in osteosarcoma tissues and normal bone tissues, and investigate the relationships between miR-9 expression, clinicopathological features and the prognosis of patients with osteosarcoma.

METHODS

The expression levels of miR-9 in osteosarcoma tissues and corresponding non-cancerous tissues were detected using a real-time quantitative assay. Differences in patient survival were determined using the Kaplan-Meier method and a log-rank test. A Cox proportional hazards regression analysis was used for univariate and multivariate analyses of prognostic values.

RESULTS

Compared to non-cancerous bone tissues, the expression levels of miR-9 in osteosarcoma tissues were significantly elevated (P < 0.001). We found that the expression level of miR-9 was significantly associated with tumor size (P = 0.011), clinical stage (P = 0.009) and distant metastasis (P < 0.001). The Kaplan-Meier curve showed that patients with low miR-9 expression survived significantly longer than patients with high miR-9 expression (P = 0.0017). Multivariate analysis suggested that miR-9 expression level (P = 0.002) is an independent prognostic factors for overall survival.

CONCLUSIONS

The findings of our study suggest that increased miR-9 expression has a strong correlation with the aggressive progression of osteosarcoma and its overexpression is a statistically significant risk factor affecting overall survival, suggesting that increased miR-9 expression could be a valuable marker of tumor progression and for prognosis of osteosarcoma.

MicroRNAs in the bile of patients with biliary strictures after liver transplantation

Biliary complications after liver transplantation remain a major cause of morbidity and reduced graft survival. Ischemic-type biliary lesions (ITBLs) are common and difficult to treat. The pathophysiology of ITBLs remains unclear, and diagnostic markers are still missing. The analysis of microRNA (miRNA) profiles is an evolving field in hepatology. Our aim was to identify specific miRNA patterns in the bile of patients with ITBLs after liver transplantation. Liver transplant patients with biliary complications were included in a cross-sectional study. Patients with ITBLs (n = 37), anastomotic strictures (ASs; n = 39), and bile duct stones (BDSs; n = 12) were compared. Patients with ITBLs were categorized by disease severity. The miRNA concentrations in bile were determined with global miRNA profiling and subsequent miRNA-specific polymerase chain reaction-mediated validation. The concentrations of microRNA 517a (miR-517a), miR-892a, and miR-106a* in bile were increased for patients with ITBLs versus patients with ASs or BDSs (P < 0.05). Categorization by ITBL severity showed higher median concentrations in patients with intrahepatic and extrahepatic strictures (P > 0.05). miR-210, miR-337-5p, miR-577, and miR-329 displayed no statistical differences. In conclusion, miR-517a, miR-892a, and miR-106a* are increased in the bile fluid of patients with ITBLs versus patients with ASs or BDSs. An analysis of miRNA profiles may be useful in the diagnosis and management of patients with ITBLs. Future studies are needed to prove the potential prognostic value of these miRNAs.

[Potential relevance of microRNAs in the diagnostics of inflammatory bowel diseases]

Inflammatory bowel diseases are chronic inflammatory disorders characterized by relapses and remissions. Several factors have been suggested to participate in their development, although their detailed pathogenesis still remains largely unknown. MicroRNAs are single strained, non-coding RNAs, consisting of 18-25 nucleotides that regulate gene expression at the posttranscriptional level. Aberrant expression of microRNAs has been found in several malignant tumors. Recently the role of microRNAs in the pathogenesis of inflammatory-autoimmune disorders (such as inflammatory bowel disease) is being intensively investigated. Beside their pathogenic roles, microRNAs can also be exploited as diagnostic markers, especially in cases where the interpretation of histological data is difficult. In this review the authors discuss recent findings in the field of microRNAs in the diagnosis and pathogenesis of inflammatory bowel diseases.

MicroRNA in gastrointestinal cancer: a step closer to reality

Despite significant strides in understanding molecular pathogenesis of cancer, gastrointestinal malignancy (gastric, colorectal, pancreatic, and liver) still ranks among the leading causes of cancer-related mortality and morbidity worldwide. One of the key clinical challenges in effectively reducing disease burden associated with gastrointestinal neoplasia stems from late diagnosis, underscoring the need for early detection, risk assessment, and intervention. Currently available screening approaches are inadequate, and the development of accurate noninvasive molecular biomarkers is very much needed, microRNAs (miRNAs) are short (20-24 nucleotides in length) noncoding RNAs that have emerged as important translational gene regulators in cancer cells. In contrast to genetic markers, miRNAs have a cancer-specific expression pattern. They are present in a remarkably stable form and can be detected in a wide variety of body fluids including blood and feces. These properties make them attractive cancer biomarker targets. Although development of miRNA biomarkers is still in its early stages, burgeoning evidence supports their potential use for development as markers for early detection, prognosis, and prediction of disease recurrence and therapeutic outcome in gastrointestinal cancers. In the future, it is likely that miRNA biomarkers will revolutionize personalized medicine and mitigate disease burden associated with gastrointestinal cancers.

MicroRNAs and cholestatic liver diseases

PURPOSE OF REVIEW

To highlight the increasing evidence supporting the concept that microRNAs (miRNAs) are involved in the cause and pathogenesis of cholestatic liver disorders.

RECENT FINDINGS

miRNAs play a key role in maintaining bile acid homeostasis and modulating pathological processes associated to liver cholestasis, such as proliferation, apoptosis, fibrosis and cancer. Changes in the expression level of specific miRNAs have been reported in serum, peripheral blood mononuclear cells or liver tissue from patients suffering from chronic cholestatic liver diseases, such as primary biliary cirrhosis.

SUMMARY

Although our understanding regarding the role of miRNAs in the development and progression of cholestatic liver diseases is still limited, in the present review, we have revised and discussed the recent information that has emerged on the role of miRNAs in the secretory function of the liver under physiological and pathological conditions. This has led to suggest their potential usefulness as biomarkers for the diagnosis and monitoring of cholestatic liver diseases, as well as tools for the development of novel therapeutic strategies.

Sensitivity of alternative testing for pancreaticobiliary cancer: a 10-y review of the literature

BACKGROUND

Biliary strictures present a diagnostic challenge to differentiate benign disease from hepatopancreaticobiliary (HPB) malignancies. Endoscopic retrograde cholangiopancreatography cytology is commonly performed in these patients; however, its sensitivity for diagnosis of HPB malignancy is poor (41.6%). Many adjunctive tests have been investigated to improve the sensitivity of HPB biopsies. To determine the best tests available, however, we reviewed the literature and performed a comparative analysis of all recently investigated tests and their sensitivities.

METHODS

A PubMed search identified articles published between 2003 and 2014, describing alternate methods for diagnosing HPB malignancies, reported sensitivity, final pathology, and had data available online. Meta-analysis was conducted for tests with multiple articles. Tests with the highest sensitivity and specificities were reported.

RESULTS

A total of 77 studies were identified. Meta-analysis was performed on the sensitivity of EUS-FNA (74.2%), fluorescence in situ hybridization (54.2%), immunostain of insulin-like growth factor 2 mRNA-binding Protein 3 (IMP3; 80.4%), IMP3 + cytology (86.4%), K homology domain containing protein overexpressed in cancer (KOC; 85.9%), S100P (77.8%), serum CA19-9 (69.3%), and K-ras mutations (47.0%) to detect malignancy. Ultimately, 12 tests were identified with superior sensitivity (85.3%-100%) and specificities (81.6%-100%) including stricture scrapping, brush sectioning, IMP3 stain + cytology, IMP3+S100A4, bile carcinoembryonic cell adhesion molecule 6 protein (±CA19-9), bile micro RNA (miRNA)-135b, serum miRNA-RNU2-1f, serum miRNA-21 (+CA19-9), peripheral blood mononuclear cells miRNA-27a-3p (+CA19-9), serum miRNA-16 + miRNA-196a (+CA19-9), peripheral blood mononuclear cells mRNAs h-TERT + CK20 + CEA + C-MET.

CONCLUSIONS

We recommend immunostaining with a panel of IMP3+KOC + S100A4 + cytology to achieve maximum sensitivity and specificity from HPB biopsies. One biliary protein (carcinoembryonic cell adhesion molecule 6) and several RNAs (bile and blood) offer exceptional sensitivity and specificity and should be tested prospectively in larger populations. Overall, this review identifies several tests to improve the sensitivity of diagnostic algorithms to identify HPB malignancies.

Risk miRNA screening of ovarian cancer based on miRNA functional synergistic network

Background

miRNAs are proved to have causal roles in tumorgenesis involving various types of human cancers, but the mechanism is not clear. We aimed to explore the effect of miRNAs on the development of ovarian cancer and the underlying mechanism.

Methods

The miRNA expression profile GSE31801 was downloaded from GEO (Gene Expression Omnibus) database. Firstly, the differentially expressed miRNAs were screened. Target genes of the miRNAs were collected from TargetScan, PicTar, miRanda, and DIANA-microT database, then the miRNA-miRNA co-regulating network was constructed using miRNA pairs with common regulated target genes. Next, the functional modules in the network were studied, the miRNA pairs regulated at least one modules were enriched to form the miRNA functional synergistic network (MFSN).

Results

Risk miRNA were selected in MFSN according to the topological structure. Transcript factors (TFs) in MFSN were identified, followed by the miRNA-transcript factor networks construction. Totally, 42 up- and 61 down-regulated differentially expressed miRNAs were identified, of which 68 formed 2292 miRNA pairs in the miRNA-miRNA co-regulating network. GO: 0007268 (synaptic transmission) and GO: 0019226 (transmission of nerve impulse) were the two common functions of miRNAs in MFSN, and hsa-miR-579 (36), hsa-miR-942 (31), hsa-miR-105 (31), hsa-miR-150 (34), and hsa-miR-27a* (32) were selected as the hub nodes in MFSN.

Conclusions

In all, 17 TFs, including CREM, ERG, and CREB1 were screened as the cancer related TFs in MFSN. Other TFs, such as BIN1, FOXN3, FOXK1, FOXP2, and ESRRG with high degrees may be inhibited in ovarian cancer. MFSN gave us a new shed light on the mechanism studies in ovarian cancer.

Significance of microRNA expression in body fluids in the diagnosis of gastrointestinal tumors

MicroRNAs are small, non-coding, single strained RNAs that regulate gene expression at the posttranscriptional level. They are involved in all major aspects of cellular functions, such as cell cycle, differentiation, migration, apoptosis etc. The role of microRNAs as potential biomarkers of several malignant diseases is being intensively investigated, since they can be found in the body fluids, too, besides their usual intracellular localisation. MicroRNAs have been detected in blood, saliva, stool, breast milk, urine, bile etc. In this review the authors discuss recent findings in the field of microRNAs in stool, bile and saliva, underlying their potential significance in the diagnosis of gastrointestinal tumors. Orv. Hetil., 2014, 155(1), 11–15.

A review of the clinical diagnosis and therapy of cholangiocarcinoma

Cholangiocarcinoma (CCA) is the second most common primary hepatic malignancy worldwide. The incidence of intrahepatic CCA is increasing, whereas that of extrahepatic CCA is decreasing. This review looks at the new advances that have been made in the management of CCA, based on a PubMed and Science Citation Index search of results from randomized controlled trials, reviews, and cohort, prospective and retrospective studies. Aggressive interventional approaches and new histopathological techniques have been developed to make a histological diagnosis in patients with high risk factors or suspected CCA. Resectability of the tumour can now be assessed using multiple radiological imaging studies; the main prognostic factor after surgery is a histologically negative resection margin. Biliary drainage and/or portal vein embolization may be performed before extended radical resection, or liver transplantation may be undertaken in combination with neoadjuvant chemotherapy or chemoradiotherapy. Though many advances have been made in the management of CCA, the standard modality of treatment has not yet been established. This review focuses on the clinical options for different stages of CCA.

Predictive value of miR-9 as a potential biomarker for nasopharyngeal carcinoma metastasis

Background:

Nasopharyngeal carcinoma (NPC) has a distinctive geographic distribution and is characterised by its strong tendency of metastasis. We aimed to examine the microRNA (miRNA) expression profiles in plasma samples of NPC patients to explore their clinical significance in disease development and progression.

Methods:

This study was divided into four steps: (1) confirmation of differentially expressed miRNAs using microarray analysis and quantitative PCR validation; (2) comparison of plasma miR-9 levels during NPC progression; (3) evaluation of the predictive performance of plasma miR-9 as a biomarker for NPC metastasis; and (4) comparison of plasma miR-9 levels between pre- and post-treatment samples.

Results:

Plasma microarray profiling identified 33 differentially expressed miRNAs between NPC patients and healthy volunteers. The significantly declined level of miR-9 in NPC patients was confirmed through two-stage validation. The low level of plasma miR-9 was significantly correlated with worse lymphatic invasion and advanced TNM stage. The plasma miR-9 could distinguish locoregional from metastatic NPC cases with a high sensitivity and specificity. Furthermore, the plasma miR-9 level was significantly elevated in post-treatment plasma compared with those pre-treatment samples.

Conclusion:

Our study reports that plasma miR-9 may serve as a useful biomarker to predict NPC metastasis and to monitor tumour dynamics.

MicroRNA profiles in graft preservation solution are predictive of ischemic-type biliary lesions after liver transplantation

BACKGROUND & AIMS

Ischemic-type biliary lesions (ITBL) are the second most common cause of graft loss after liver transplantation. Though the exact pathophysiology of ITBL is unknown, bile duct injury during graft preservation is considered to be a major cause. Here we investigated whether the release of cholangiocyte-derived microRNAs (CDmiRs) during graft preservation is predictive of the development of ITBL after liver transplantation.

METHODS

Graft preservation solutions (perfusates) and paired liver biopsies collected at the end of cold ischemia were analysed by RT-qPCR for CDmiR-30e, CDmiR-222, and CDmiR-296 and hepatocyte-derived miRNAs (HDmiRs) HDmiR-122 and HDmiR-148a. MicroRNAs in perfusates were evaluated on their stability by incubation and fractionation experiments. MicroRNA profiles in perfusates from grafts that developed ITBL (n=20) and grafts without biliary strictures (n=37) were compared.

RESULTS

MicroRNAs in perfusates were proven to be stable and protected against degradation by interacting proteins. Ratios between HDmiRs/CDmiRs were significantly higher in perfusates obtained from grafts that developed ITBL (p<0.01) and were identified as an independent risk factor by multivariate analysis (p<0.01, HR: 6.89). The discriminative power of HDmiRs/CDmiRs in perfusates was validated by analysis of separate brain death- (DBD) and cardiac death donors (DBD; p ≤ 0.016) and was superior to expression in liver biopsies (C=0.77 in perfusates vs. C<0.50 in biopsies).

CONCLUSIONS

This study demonstrates that differential release of CDmiRs during graft preservation is predictive of the development of ITBL after liver transplantation. This provides new evidence for the link between graft-related bile duct injury and the risk for later development of ITBL.

miR-9 regulation of BRCA1 and ovarian cancer sensitivity to cisplatin and PARP inhibition

BACKGROUND

Expression of BRCA1 is commonly decreased in sporadic ovarian cancer, and this is associated with platinum sensitivity and favorable prognosis. However, multiple mechanisms underlying low BRCA1 expression are not fully understood.

METHODS

A bioinformatics-driven microRNA (miR) library screening was used to identify miRs that regulate BRCA1 expression. The effects of miR-9 on cisplatin (cDDP) and PARP inhibitor sensitivity were measured in ovarian cancer cells and C13* xenograft mice (n = 6 per group). The roles of miR-9 on prognosis were assessed in a cohort of ovarian cancer patients (n = 113) with Kaplan-Meier and Cox proportional hazards analyses. All statistical tests were two-sided.

RESULTS

Reverse miR library screening revealed that miR-9 reduced the normalized luciferase activity to 60.3% (95% confidence interval [CI] = 52.0% to 68.5%; P < .001). miR-9 bound directly to the 3'-UTR of BRCA1 and downregulated BRCA1 expression in ovarian cancer cells. Treatment with miR-9 agomiR sensitized BRCA1-proficient C13* xenograft tumors to cisplatin and AG014699. In serous ovarian cancer, higher levels of miR-9 were inversely correlated with BRCA1 expression (Spearman rank correlation: R (2) = 0.379; P = .003). Patients with higher levels of miR-9 had better chemotherapy response, platinum sensitivity, and longer progression-free survival (PFS) (high vs low miR-9 expression: median PFS = 26.4 months, 95% CI = 13.8 to 39.0 months vs median PFS = 15.4 months, 95% CI = 6.8 to 23.9 months, P = .01).

CONCLUSIONS

miR-9 mediates the downregulation of BRCA1 and impedes DNA damage repair in ovarian cancer. miR-9 may improve chemotherapeutic efficacy by increasing the sensitivity of cancer cells to DNA damage and may impact ovarian cancer therapy.