miRNA Expression In Tumors Research Articles

Synthesis and Regulation of miRNA, Its Role in Oncogenesis, and Its Association with Colorectal Cancer Progression, Diagnosis, and Prognosis.

The dysfunction of several types of regulators, including miRNAs, has recently attracted scientific attention for their role in cancer-associated changes in gene expression. MiRNAs are small RNAs of ~22 nt in length that do not encode protein information but play an important role in post-transcriptional mRNA regulation. Studies have shown that miRNAs are involved in tumour progression, including cell proliferation, cell cycle, apoptosis, and tumour angiogenesis and invasion, and play a complex and important role in the regulation of tumourigenesis. The detection of selected miRNAs may help in the early detection of cancer cells, and monitoring changes in their expression profile may serve as a prognostic factor in the course of the disease or its treatment. MiRNAs may serve as diagnostic and prognostic biomarkers, as well as potential therapeutic targets for colorectal cancer. In recent years, there has been increasing evidence for an epigenetic interaction between DNA methylation and miRNA expression in tumours. This article provides an overview of selected miRNAs, which are more frequently expressed in colorectal cancer cells, suggesting an oncogenic nature.

Small RNA Deep Sequencing Uncovers microRNAs Associated with Hearing Loss in Vestibular Schwannoma.

To analyze the correlation between the miRNA expression profile in vestibular schwannoma (VS) tumor tissue and preoperative patient's hearing status, using the RNA-seq technique. Nineteen tumor samples were collected from patients operated for VS in a Tertiary Academic Center. Samples were classified into "good hearing" and "poor hearing" study group based on the results of audiometric studies. Tumor miRNA expression was analyzed using high-throughput RNA sequencing (RNA-seq) technique, using NovaSeq 6000 Illumina system. Functional analysis was performed with the use of DIANA miRpath v. 4.0 online tool. The most overexpressed miRNAs in VS samples derived from poor hearing patients belonged to miR 449a/b, miR 15/16-1, and hypoxamiR families. Functional analysis showed that the differentially expressed miRNAs regulate cellular pathways associated with hypoxia, adherence junction functions, and signaling pathways such as Hippo, FOXO, MAPK, and Wnt signaling pathway. Our study identified a specific miRNA expression profile in VS tumor tissues that correlates with hearing impairment. These results suggest potential new molecular mechanisms related to hearing loss in the course of VS. 3 (cohort study) Laryngoscope, 134:3778-3785, 2024.

High-throughput RNA sequencing identifies the miRNA expression profile, target genes, and molecular pathways contributing to growth of sporadic vestibular schwannomas.

To assess the differences in the miRNA expression profile between small (stage I Koos classification) and large solid vestibular schwannoma (VS) tumors, using the RNA-seq technique. Twenty tumor samples (10 small and 10 large tumors) were collected from patients operated for VS in a Tertiary Academic Center. Tumor miRNA expression was analyzed using high-throughput RNA sequencing (RNA-seq) technique, with NovaSeq 6000 Illumina system. Bioinformatics analysis was done using statistical software R. Gene enrichment and functional analysis was performed using miRTargetLink 2.0 and DIANA miRpath 3.0 online tools. We identified 9 differentially expressed miRNAs in large VS samples: miR-7, miR-142 (-3p and -5p), miR-155, miR-342, miR-1269, miR-4664, and miR-6503 were upregulated, whereas miR-204 was significantly down-regulated in comparison to small VS samples. Gene enrichment analysis showed that the most enriched target genes were SCD, TMEM43, LMNB2, JARID2, and CCND1. The most enriched functional pathways were associated with lipid metabolism, along with signaling pathways such as Hippo and FOXO signaling pathway. We identified a set of 9 miRNAs that are significantly deregulated in large VS in comparison to small, intracanalicular tumors. The functional enrichment analysis of these miRNAs suggests novel mechanisms, such as that lipid metabolism, as well as Hippo and FOxO signaling pathways that may play an important role in VS growth regulation.

Expression of AhR-regulated miRNAs in non-small cell lung cancer in smokers and never smokers.

Smoking is a risk factor for non-small cell lung cancer (NSCLC). The most common subtypes of NSCLC are lung adenocarcinoma (LAC) and squamous cell carcinoma (SCC). The cigarette smoke contains aryl hydrocarbon receptor (AhR) ligands, such as benzo(a)pyrene (BaP). By activating the AhR, BaP can change the expression of many genes, including miRNA-encoding genes. In this study, we have evaluated the expression of few miRNAs potentially regulated by AhR (miR-21, -342, -93, -181a, -146a), as well as CYP1A1, a known AhR target gene, in lung tumor samples from smoking (n=40) and non-smoking (n=30) patients with LAC and from smoking patients with SCC (n=40). We have also collected macroscopically normal lung tissue >5 cm from the tumor margin. We compared the obtained data on the miRNA expression in tumors with data from The Cancer Genome Atlas (TCGA). We found that in 76.7% of non-smoking LAC patients, CYP1A1 mRNA was not detected in tumor and normal lung tissues, while in smoking patients, CYP1A1 expression was detected in tumors in almost half of the cases (47.5% for SCC and 42.5% for LAC). The expression profile of AhR-regulated miRNAs differed between LAC and SCC and depended on the smoking status. In LAC patients, the expression of oncogenic miRNA-21 and miRNA-93 in tumors was higher than in normal lung tissue from the same patients. However, in SCC patients from our sample, the levels of these miRNAs in tumor and non-transformed lung tissue did not differ significantly. The results of our studies and TCGA data indicate that the expression levels of miRNA-181a and miRNA-146a in LAC are associated with smoking: expression of these miRNAs was significantly lower in tumors of smokers. It is possible that their expression is regulated by AhR and AhRR (AhR repressor), and inhibition of AhR by AhRR leads to a decrease in miRNA expression in tumors of smoking patients. Overall, these results confirm that smoking has an effect on the miRNA expression profile. This should be taken into account when searching for new diagnostic and therapeutic targets for NSCLC.

Therapeutic Delivery of Tumor Suppressor miRNAs for Breast Cancer Treatment.

The death rate from breast cancer (BC) has dropped due to early detection and sophisticated therapeutic options, yet drug resistance and relapse remain barriers to effective, systematic treatment. Multiple mechanisms underlying miRNAs appear crucial in practically every aspect of cancer progression, including carcinogenesis, metastasis, and drug resistance, as evidenced by the elucidation of drug resistance. Non-coding RNAs called microRNAs (miRNAs) attach to complementary messenger RNAs and degrade them to inhibit the expression and translation to proteins. Evidence suggests that miRNAs play a vital role in developing numerous diseases, including cancer. They affect genes critical for cellular differentiation, proliferation, apoptosis, and metabolism. Recently studies have demonstrated that miRNAs serve as valuable biomarkers for BC. The contrast in the expression of miRNAs in normal tissue cells and tumors suggest that miRNAs are involved in breast cancer. The important aspect behind cancer etiology is the deregulation of miRNAs that can specifically influence cellular physiology. The main objective of this review is to emphasize the role and therapeutic capacity of tumor suppressor miRNAs in BC and the advancement in the delivery system that can deliver miRNAs specifically to cancerous cells. Various approaches are used to deliver these miRNAs to the cancer cells with the help of carrier molecules, like nanoparticles, poly D, L-lactic-co-glycolic acid (PLGA) particles, PEI polymers, modified extracellular vesicles, dendrimers, and liposomes. Additionally, we discuss advanced strategies of TS miRNA delivery techniques such as viral delivery, self-assembled RNA-triple-helix hydrogel drug delivery systems, and hyaluronic acid/protamine sulfate inter-polyelectrolyte complexes. Subsequently, we discuss challenges and prospects on TS miRNA therapeutic delivery in BC management so that miRNAs will become a routine technique in developing individualized patient profiles.

Mechanisms Controlling MicroRNA Expression in Tumor.

MicroRNAs (miRNAs) are widely present in many organisms and regulate the expression of genes in various biological processes such as cell differentiation, metabolism, and development. Numerous studies have shown that miRNAs are abnormally expressed in tumor tissues and are closely associated with tumorigenesis. MiRNA-based cancer gene therapy has consistently shown promising anti-tumor effects and is recognized as a new field in cancer treatment. So far, some clinical trials involving the treatment of malignancies have been carried out; however, studies of miRNA-based cancer gene therapy are still proceeding slowly. Therefore, furthering our understanding of the regulatory mechanisms of miRNA can bring substantial benefits to the development of miRNA-based gene therapy or other combination therapies and the clinical outcome of patients with cancer. Recent studies have revealed that the aberrant expression of miRNA in tumors is associated with promoter sequence mutation, epigenetic alteration, aberrant RNA modification, etc., showing the complexity of aberrant expression mechanisms of miRNA in tumors. In this paper, we systematically summarized the regulation mechanisms of miRNA expression in tumors, with the aim of providing assistance in the subsequent elucidation of the role of miRNA in tumorigenesis and the development of new strategies for tumor prevention and treatment.

Methylation Status of Gene Bodies of Selected microRNA Genes Associated with Neoplastic Transformation in Equine Sarcoids

Horses are of great importance in recreation, livestock production, as working animals in poorly developed countries, and for equine-assisted therapy. Equine sarcoids belong to the most commonly diagnosed tumors in this species. They may cause discomfort, pain, and can lead to the permanent impairment of motor function. The molecular bases of their formation are still under investigation. Our previous studies revealed altered microRNA (miRNA) expression and DNA methylation levels in sarcoid tumors. Abnormal patterns of methylation may be responsible for changes in gene expression levels, including microRNAs. Recently, the DNA methylation of gene bodies has also been shown to have an impact on gene expression. Thus, the aim of the study was to investigate the methylation pattern of gene bodies of chosen miRNAs identified in sarcoid tissue (miR-101, miR-10b, miR-200a, and miR-338-3p), which have also been established to play roles in neoplastic transformation. To this end, we applied qRT-PCR, Bisulfite Sequencing PCR (BSP), and Mquant methods. As a result, we identified the statistically significant downregulation of pri-mir-101-1, pri-mir-10b, and pri-mir-200a in the sarcoid samples in comparison to the control. The DNA methylation analysis revealed their hypermethylation. This suggests that DNA methylation may be one mechanism responsible for the downregulation of theses miRNAs. However, the identified differences in the methylation levels are not very high, which implies that other mechanisms may also underlie the downregulation of the expression of these miRNAs in equine sarcoids. For the first time, the results obtained shed light on microRNA expression regulation by gene body methylation in equine sarcoids and provide bases for further deeper studies on other mechanisms influencing the miRNA repertoire.

Pan-cancer analysis of microRNA expression profiles highlights microRNAs enriched in normal body cells as effective suppressors of multiple tumor types: A study based on TCGA database

BackgroundMicroRNAs (miRNAs) are frequently deregulated in various types of cancer. While antisense oligonucleotides are used to block oncomiRs, delivery of tumour-suppressive miRNAs holds great potential as a potent anti-cancer strategy. Here, we aim to determine, and functionally analyse, miRNAs that are lowly expressed in various types of tumour but abundantly expressed in multiple normal tissues.MethodsThe miRNA sequencing data of 14 cancer types were downloaded from the TCGA dataset. Significant differences in miRNA expression between tumor and normal samples were calculated using limma package (R programming). An adjusted p value < 0.05 was used to compare normal versus tumor miRNA expression profiles. The predicted gene targets were obtained using TargetScan, miRanda, and miRDB and then subjected to gene ontology analysis using Enrichr. Only GO terms with an adjusted p < 0.05 were considered statistically significant. All data from wet-lab experiments (cell viability assays and flow cytometry) were expressed as means ± SEM, and their differences were analyzed using GraphPad Prism software (Student’s t test, p < 0.05).ResultsBy compiling all publicly available miRNA profiling data from The Cancer Genome Atlas (TCGA) Pan-Cancer Project, we reveal a small set of tumour-suppressing miRNAs (which we designate as ’normomiRs’) that are highly expressed in 14 types of normal tissues but poorly expressed in corresponding tumour tissues. Interestingly, muscle-enriched miRNAs (e.g. miR-133a/b and miR-206) and miRNAs from DLK1-DIO3 locus (e.g. miR-381 and miR-411) constitute a large fraction of the normomiRs. Moreover, we define that the CCCGU motif is absent in the oncomiRs’ seed sequences but present in a fraction of tumour-suppressive miRNAs. Finally, the gain of function of candidate normomiRs across several cancer cell types indicates that miR-206 and miR-381 exert the most potent inhibition on multiple cancer types in vitro.ConclusionOur results reveal a pan-cancer set of tumour-suppressing miRNAs and highlight the potential of miRNA-replacement therapies for targeting multiple types of tumour.

Abstract P5-13-26: The future of HER2-positive breast cancer patients might be written in miRNAs: An exploratory analysis from the NeoALTTO study

Abstract Importance. Neoadjuvant therapy with dual HER2 blockade improved pathological complete response (pCR) rate. Nevertheless, it would be desirable to identify patients exquisitely responsive to single agent trastuzumab to minimize or avoid overtreatment. Objective. To evaluate the predictive and prognostic value of basal primary tumor miRNA expression profile within the trastuzumab arm of the NeoALTTO study.Design, Setting and Participants. RNA samples from baseline biopsies were randomized into training (n =45) and testing (n =47) sets. After normalization, miRNAs associated with Event-free survival (EFS) and pCR were identified by univariate analysis. Multivariate models were implemented to generate specific signatures which were first confirmed, and then analyzed according to other clinical and pathological variables.Main outcomes and measures. Association between miRNA expression and pCR and/or EFS.Results. We identified a prognostic signature including hsa-miR-153-3p (HR 1.831, 95%CI: 1.34-2.50) and hsa-miR-219a-5p (HR 0.629, 95%CI: 0.50 - 0.78). For two additional miRNAs (miR-215-5p and miR-30c-2-3p), we found a statistically significant interaction term with pCR (p.interaction: 0.017 and 0.038, respectively). Besides, a two-miRNA signature was predictive of pCR (hsa-miR-31-3p, OR 0.70, 95%CI: 0.53 - 0.92, and hsa-miR-382-3p, OR: 1.39, 95%CI: 1.01 -1.91). Notably, the performance of this predictive miRNA signature resembled that of the genomic classifiers PAM50 and TRAR, and did not improve when the extended models were fitted.Conclusions and relevance. Analysis of primary tumor tissue miRNAs holds the potential of a parsimonious tool to identify patients with differential clinical outcomes after trastuzumab based neoadjuvant therapy. Trial registration. ClinicalTrials.gov Identifier: NCT00553358. Table 1.MiRNAs associated with EFS. Results of the univariate Cox regression model- training set.miRNAsHR95% CIhsa-miR-12000.671(0.512; 0.879)ahsa-miR-1238-3p0.669(0.543; 0.826)ahsa-miR-12650.839(0.705; 0.997)ahsa-miR-129-5p0.785(0.628; 0.980)ahsa-miR-153-3p1.412(1.026; 1.943)ahsa-miR-15390.826(0.697; 0.979)ahsa-miR-1908-5p0.796(0.648; 0.978)ahsa-miR-205-5p0.737(0.553; 0.982)hsa-miR-219a-5p0.787(0.627; 0.989)ahsa-miR-25-5p0.566(0.391; 0.819)ahsa-miR-3000.581(0.399; 0.845)ahsa-miR-382-3p0.791(0.636; 0.985)ahsa-miR-4920.774(0.635; 0.944)ahsa-miR-519a-3p0.834(0.696; 0.998)ahsa-miR-551b-5p0.666(0.452; 0.981)ahsa-miR-5830.727(0.549; 0.963)ahsa-miR-6001.373(1.03; 1.829)ahsa-miR-6260.819(0.673; 0.998)ahsa-miR-651-5p0.611(0.382; 0.977)hsa-miR-7610.845(0.721; 0.991)ahsa-miR-891b0.658(0.479; 0.904)ahsa-miR-92a-2-5p0.787(0.637; 0.971)ahsa-miR-937-3p0.748(0.578; 0.967)aHR, Hazard Ratio; CI, Confidence Intervala microRNAs retained its statistically significance (at 10%) also when normalized for the overall mean. Table 2.MiRNAs associated with pCR. Results of the univariate logistic model - training set.miRNAsOR95% CIhsa-miR-132-3p0.410(0.169; 0.991)ahsa-miR-23b-5p0.520(0.316; 0.856)ahsa-miR-31-3p0.566(0.351; 0.912)ahsa-miR-31-5p0.508(0.291; 0.887)ahsa-miR-330-3p0.501(0.251; 0.999)hsa-miR-34b-3p0.673(0.474; 0.956)ahsa-miR-382-3p1.392(1.006; 1.925)ahsa-miR-548j-5p1.702(1.090; 2.658)aOR, Odds Ratio; CI, Confidence Interval. a microRNAs retained its statistically significance (at 10%) also when normalized for the overall mean. 2 Citation Format: Marilena Valeria Iorio, Sara Pizzamiglio, Giulia Cosentino, Chiara M Ciniselli, Loris De Cecco, Alessandra Cataldo, Ilaria Plantamura, Tiziana Triulzi, Sarra El-abed, Yingbo Wang, Mohammed Bajji, Paolo Nuciforo, Jens Huober, Susan Ellard, David Rimm, Andrea Gombos, Mariagrazia Daidone, Paolo Verderio, Elda Tagliabue, Serena Di Cosimo. The future of HER2-positive breast cancer patients might be written in miRNAs: An exploratory analysis from the NeoALTTO study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-13-26.

MicroRNA profiling in a case-control study of African American women with uterine serous carcinoma

ObjectiveUterine serous carcinoma (USC) is an aggressive subtype of endometrial cancer associated with worse survival outcomes in African American (AA) patients. This study evaluated tumor miRNA expression by race, clinical and tumor characteristics, and survival outcomes. MethodsFFPE tumor tissue from hysterectomy specimens was identified for 29 AA cases. Case matching was performed by computer-based random assignment in a 1:1 ratio with Caucasian controls based on age, stage and histologic subtype (pure vs. mixed). RNA was extracted from 77 specimens (54 tumors and 23 matched normal endometrium). MicroRNA array profiling was performed by microRNA Hi-Power Labeling (Hy3/Hy5) and hybridization to miRCURY LNA microRNA Array 7th Gen. ResultsClinical and treatment characteristics were similar for cases and controls, although use of adjuvant radiation was less common in African Americans (p = 0.03). Of 968 miRNAs analyzed, 649 were differentially expressed in normal endometrium vs. tumor. When compared by race, histologic subtype, stage or presence of LVI, no differentially expressed miRNAs were identified. In patients with disease recurrence at 3 years, the three most upregulated miRNAs were miR-1, miR-21-5p and miR-223. Of these, increased miR-223 expression (>median) was associated with worse OS (p = 0.0496) in an independent dataset (TCGA dataset) comprising of 140 patients with USC (mixed or pure serous). After adjusting for age, ethnicity and BMI, upregulation of miR-223 remained risk factor for death (adjusted HR 2.87, 95% CI 1.00–8.27). ConclusionsMiRNA profiling did not identify biological differences between AA and Caucasian patients with USC. Upregulation of miR-223 may be a prognostic factor in USC.

EXTH-41. THE microRNA miR-138 MAY BE RESPONSIBLE FOR SOME OF THE EFFECTS OF METABOLIC KETOSIS ON MALIGNANT GLIOMA

Abstract We and others have demonstrated that altering metabolism through the use of a ketogenic diet (KD) has numerous effects in mouse models of malignant glioma including slowed growth, reduced hypoxia and angiogenesis, enhanced survival and potentiation of the effects of radiation and chemotherapy. These effects are recapitulated in vitro when the ketone β-hydroxybutyrate (BHB) is added to mouse and human malignant glioma cells grown under high glucose conditions. BHB has been demonstrated to be an epigenetic modifier, providing a potential mechanism for the pluripotent effects of ketones even in the presence of high glucose. Therefore, we have analyzed alterations in microRNA (miRNA) expression in tumors and cells treated with a KD or BHB, respectively. MicroRNAs are short, single-stranded, noncoding RNAs that posttranscriptionally control gene expression. Each miRNA can affect the expression of many genes and they are implicated in all hallmarks of cancer. We found a number of miRNAs deregulated in tumor tissue from mice fed a KD, particularly mmu-miR-138 which was increased over 30-fold relative to tumors from mice fed a standard diet. MiR-138 is involved in a variety of anti-tumor effects that correlate with our data from KD treated gliomas. We have shown that ketones radiosensitize glioma cells, potentially through a reduction in DNA damage repair. MiR-138 has been shown to reduce the expression of H2AX which plays a key role in sensing and repairing DNA damage. Hypoxia inducible factor-1α (HIF-1α) is also a target of miR-138, and we have demonstrated a reduction in hypoxia, angiogenesis and the expression of HIF-1α in tumors from mice fed a KD. Furthermore, when we genetically engineered tumor cells to express miR-138 and injected them into mice, only necrotic tumor foci were found. Thus, we suggest that miR-138 is an important regulatory mechanism for the anti-tumor actions of metabolic ketosis in glioma.

Development of Prediction Model Including MicroRNA Expression for Sentinel Lymph Node Metastasis in ER-Positive and HER2-Negative Breast Cancer.

The aim of our study is to find microRNAs (miRNAs) associated with sentinel lymph node metastasis (SLNM) and to develop a prediction model for SLNM in ER-positive and HER2-negative (ER+/HER2-) breast cancer. In the present study, only ER+/HER2- primary breast cancer was considered. The discovery set for SLNM-associated miRNAs included 10 tumors with and 10 tumors without SLNM. The training and validation sets both included 100 tumors. miRNA expression in tumors was examined comprehensively by miRNA microarray in the discovery set and by droplet digital PCR in the training and validation sets. In the discovery set, miR-98, miR-22, and miR-223 were found to be significantly (P < 0.001, fold-change > 2.5) associated with SLNM. In the training set, we constructed the prediction model for SLNM using miR-98, tumor size, and lymphovascular invasion (LVI) with high accuracy (AUC, 0.877). The accuracy of this prediction model was confirmed in the validation set (AUC, 0.883), and it outperformed the conventional Memorial Sloan Kettering Cancer Center nomogram. In situ hybridization revealed the localization of miR-98 expression in tumor cells. We developed a prediction model consisting of miR-98, tumor size, and LVI for SLNM with high accuracy in ER+/HER2- breast cancer. This model might help decide the indication for SLN biopsy in this subtype.

Metformin's Modulatory Effects on miRNAs Function in Cancer Stem Cells-A Systematic Review.

Cancer stem cells (CSCs) have been reported in various hematopoietic and solid tumors, therefore, are considered to promote cancer progression, metastasis, recurrence and drug resistance. However, regulation of CSCs at the molecular level is not fully understood. microRNAs (miRNAs) have been identified as key regulators of CSCs by modulating their major functions: self-renewal capacity, invasion, migration and proliferation. Various studies suggest that metformin, an anti-diabetic drug, has an anti-tumor activity but its precise mechanism of action has not been understood. The present article was written in accordance to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. We systematically reviewed evidence for metformin’s ability to eradicate CSCs through modulating the expression of miRNAs in various solid tumors. PubMed and MEDLINE were searched from January 1990 to January 2020 for in vitro studies. Two authors independently selected and reviewed articles according to predefined eligibility criteria and assessed risk of bias of included studies. Four papers met the inclusion criteria and presented low risk bias. All of the included studies reported a suppression of CSCs’ major function after metformin dosage. Moreover, it was showed that metformin anti-tumor mechanism of action is based on regulation of miRNAs expression. Metformin inhibited cell survival, clonogenicity, wound-healing capacity, sphere formation and promotes chemosensitivity of tumor cells. Due to the small number of publications, aforementioned evidences are limited but may be consider as background for clinical studies.

DNA Methylation Influences miRNA Expression in Gonadotroph Pituitary Tumors.

microRNAs are involved in pathogenesis of cancer. DNA methylation plays a role in transcription of miRNA-encoding genes and may contribute to changed miRNA expression in tumors. This issue was not investigated in pituitary neuroendocrine tumors (PitNETs) previously. DNA methylation patterns, assessed with HumanMethylation450K arrays in 34 PitNETs and five normal pituitaries, were used to determine differentially methylated CpGs located at miRNA genes. It showed aberrant methylation in regions encoding for 131 miRNAs. DNA methylation data and matched miRNA expression profiles, determined with next-generation sequencing (NGS) of small RNAs, were correlated in 15 PitNETs. This showed relationship between methylation and expression levels for 12 miRNAs. DNA methylation and expression levels of three of them (MIR145, MIR21, and MIR184) were determined in the independent group of 80 tumors with pyrosequencing and qRT-PCR and results confirmed both aberrant methylation in PitNETs and correlation between methylation and expression. Additionally, in silico target prediction was combined with analysis of established miRNA profiles and matched mRNA expression pattern, assessed with amplicon-based NGS to indicate putative target genes of epigenetically deregulated miRNAs. This study reveals aberrant DNA methylation in miRNA-encoding genes in gonadotroph PitNETs. Methylation changes affect expression level of miRNAs that regulate putative target genes with tumorigenesis-relevant functions.

Peripheral circulation miRNA expression of pediatric brain tumors and its relation to tumor miRNA expression levels.

Micro RNAs (miRNAs) in peripheral biofluids (e.g., blood, saliva, urine) have been investigated as potential sources of diagnostic and prognostic information for a variety of tumor types, including pediatric brain tumors. While significant predictive associations have been identified between unique serum miRNA concentrations and some pediatric brain tumors, it is unclear whether serum miRNA abnormalities in pediatric brain tumor patients are representative of miRNA alterations in the tumor tissue compartment or whether they represent host tissue reactions to the presence of a brain tumor. The authors sought to identify whether serum miRNA changes in pediatric brain tumor patient sera could be explained by miRNA alterations within their tumors. Matched serum and tissue samples were taken from a cohort of pediatric brain tumor patients (juvenile pilocytic astrocytoma [JPA] = 3, medulloblastoma = 4, ependymoma = 3), and unmatched control samples (n = 5) were acquired from control pediatric patients without oncological diagnoses. Extracted RNAs were tested within an array of 84 miRNAs previously noted to be relevant in a variety of brain tumors. miR-26a-5p correlated strongly in JPA patients within both the serum and tumor tissue samples (R2 = 0.951, p = 0.046), and serum levels were highly predictive of JPA (area under the curve = 0.751, p = 0.027). No other miRNAs that were significantly correlated between biological compartments were significantly associated with brain tumor type. In total, 15 of 84 tested miRNAs in JPA patients, 14 of 84 tested miRNAs in ependymoma patients, and 4 of 84 tested miRNAs in medulloblastoma patients were significantly, positively correlated between serum and tumor tissue compartments (R2 > 0.950, p < 0.05). The majority of miRNA changes in pediatric brain tumor patient sera that are significantly associated with the presence of a brain tumor do not correlate with brain tumor miRNA expression levels. This suggests that peripheral miRNA changes within pediatric brain tumor patients likely derive from tissues other than the tumors themselves.

Tumor miRNA expression profile is related to vestibular schwannoma growth rate.

Our objective was to investigate if the tumor microRNA (miRNA) expression profile was related to tumor growth rate. Growth-related miRNAs might be potential targets for future therapeutic intervention. Tumor tissue was sampled during surgery of patients with a sporadic vestibular schwannoma. Tumor growth rate was determined by tumor measurement on the two latest pre-operative MRI scans. Tumor miRNA expression was analyzed using the Affymetrix Gene Chip® protocol, and CEL files were generated using GeneChip® Command Console® Software and normalized using Partek Genomics Suite 6.5. The CEL files were analyzed using the statistical software program R. Principal component analysis, affected gene ontology analysis, and analysis of miRNA expression fold changes were used for analysis of potential relations between miRNA expression profile and tumor growth rate. Tumor miRNA expression is related to the growth rate of sporadic vestibular schwannomas. Rapid tumor growth is associated with deregulation of several miRNAs, including upregulation of miR-29abc, miR-19, miR-340-5p, miR-21, and miR-221 and downregulation of miR-744 and let-7b. Gene ontologies affected by the deregulated miRNAs included neuron development and differentiation, gene silencing, and negative regulation of various biological processes, including cellular and intracellular signaling and metabolism.

Phthalate Exposures and MicroRNA Expression in Uterine Fibroids: The FORGE Study

Phthalates are associated with multiple, adverse reproductive outcomes including increased risk of uterine leiomyoma (fibroids). Phthalates can interact with epigenetic modifications including microRNAs (miRNAs), which help regulate processes crucial to fibroid pathogenesis. However, no prior study has examined the influence of phthalates on miRNA expression in fibroid tumors. We conducted a preliminary, cross-sectional study to examine the associations between phthalate exposures and miRNA expression levels in fibroid tumors and to explore potential effect modification by race/ethnicity. We quantified expression levels of 754 miRNAs in fibroid tumor samples and analyzed spot urine samples for phthalate metabolites collected from 45 pre-menopausal women undergoing surgery for fibroid treatment at an academic hospital. Associations between miRNA levels in fibroids and phthalate biomarkers were evaluated using linear regression adjusting for age, race/ethnicity, and body mass index (BMI). Statistical tests were adjusted for multiple comparisons. We also performed in silico Ingenuity Pathway Analysis to identify the biological pathways that are regulated by phthalate-associated miRNAs. Mono-hydroxybutyl phthalate and mono(2-ethyl-5-hydroxyhexyl) phthalate were positively associated with miR-10a-5p (β = 0.76, 95% CI = [0.40, 1.11]) and miR-577 (β = 1.06, 95% CI = [0.53, 1.59]), respectively. A total of 8 phthalate-miRNA associations varied by race/ethnicity (qinteraction < 0.10). Pathway analysis revealed that mRNA gene targets of phthalate-associated miRNAs were significantly associated with multiple fibroid-related processes including angiogenesis, apoptosis, and proliferation of connective tissues. Collectively, these data suggest that exposures to some phthalates are associated with miRNA in fibroids, and that associations may vary by race/ethnicity. Validation of these findings may provide insight into mechanisms underlying associations between phthalates and fibroids and contribute to novel hypotheses regarding racial/ethnic disparities in fibroids.

Expression of selected microRNAs in pancreatic ductal adenocarcinoma: is there a relation to tumor morphology, progression and patient's outcome?

Pancreatic ductal adenocarcinoma (PDAC) remains a disease with extremely poor prognosis and limited effective available treatment. Differential expression of miRNAs isolated from tumor tissue has been proposed as a marker for tumor diagnosis, progression, and prognosis. Nevertheless, the prognostic value of miRNAs expression in PDACs for patient outcome still remains unclear. Expression of 7 selected miRNAs, isolated from FFPE samples of 54 PDAC patients, was quantified using RT-qPCR. The relationship of miRNA expression levels with tumor histology, clinicopathological characteristics, patient overall survival (OS), and progress-free survival (PFS), was subsequently evaluated. Overexpression of miR-21, miR-155, and miR-210 was observed in PDACs (up to 72.62, 232.36, and 181.38-fold, respectively), in comparison with non-neoplastic tissues. On the other hand, miR-96 and miR-217 were significantly downregulated in PDACs (up to one hundred times). No differences were, however, noticed between cancer and normal tissues for the expression levels of miR-148a and miR-196a. On the other hand, expression levels of all 7 miRNAs failed to demonstrate a significant correlation with parameters of tumor progression, such as tumor stage, grade, nodal involvement, perineural, and vascular invasion. The positive correlation of miR-210 levels was, however, observed with patient age (ρ=0.35). Additionally, miR-148a and miR-217 expressions have shown a positive association with tubular tumor growth pattern (ρ=0.39; ρ=0.28). The negative correlation of miR-148a values was also demonstrated with dissociative growth pattern and nuclear atypia (ρ=-0.30; ρ=-0.27). Finally, no statistically significant correlation could be demonstrated with the expression levels of all 7 tested miRNAs and PDAC patient survival; neither for OS nor for PFS (p>0.05). Our data have confirmed abnormal miRNAs expression in PDACs in comparison with adjacent non-neoplastic tissue. On the other hand, no correlation was discovered between miRNA expression and parameters of tumor progression. We have found a significant association between histologic tumor growth patterns and miRNA expression, making this work the first study, which analyses this aspect of PDAC. Finally, in our group of patients, no relationship of miRNA levels and patient prognosis could be demonstrated. Therefore, further investigation is required to evaluate the predictive and prognostic potential of miRNAs in a clinical setting.

Defining fallopiantube-derived miRNA cancer signatures.

BackgroundMicroRNAs have recently emerged as promising circulating biomarkers in diverse cancer types, including ovarian cancer. We utilized conditional, doxycycline‐induced fallopian tube (FT)‐derived cancer models to identify changes in miRNA expression in tumors and plasma, and further validated the murine findings in high‐grade ovarian cancer patient samples.MethodsWe analyzed 566 biologically informative miRNAs in doxycycline‐induced FT and metastatic tumors as well as plasma samples derived from murine models bearing inactivation of Brca, Tp53, and Pten genes. We identified miRNAs that showed a consistent pattern of dysregulated expression and validated our results in human patient serum samples.ResultsWe identified six miRNAs that were significantly dysregulated in doxycycline‐induced FTs (P < .05) and 130 miRNAs differentially regulated in metastases compared to normal fallopian tissues (P < .05). Furthermore, we validated miR‐21a‐5p, miR‐146a‐5p, and miR‐126a‐3p as dysregulated in both murine doxycycline‐induced FT and metastatic tumors, as well as in murine plasma and patient serum samples.ConclusionsIn summary, we identified changes in miRNA expression that potentially accompany tumor development in murine models driven by commonly found genetic alterations in cancer patients. Further studies are required to test both the function of these miRNAs in driving the disease and their utility as potential biomarkers for diagnosis and/or disease progression.

Serum miR-182 is a predictive biomarker for dichotomization of risk of hepatocellular carcinoma in rats.

Exploration of animal models leads to discoveries that can reveal candidate biomarkers for translation to human populations. Herein, a model of hepatocarcinogenesis and protection was used in which rats treated with aflatoxin (AFB1 ) daily for 28 days (200 µg/kg BW) developed tumors compared with rats completely protected from tumors by concurrent administration of the chemoprotective agent, 1-[2-cyano-3-,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Im). Differential expression of miRNAs in tumors (AFB1 ) and nontumor (AFB1 + CDDO-Im) bearing livers and their levels in sera over the life-course of the animals was determined. miRNA transcriptome analysis identified 17 miRNAs significantly upregulated at greater than five-fold in the tumors. The ten most dysregulated miRNAs judged by fold-change and biological significance were selected for further study, including liver-specific miR-122-5p. Validation of sequencing results by real-time PCR confirmed the upregulation of the majority of these miRNAs in tumors, including miR-182, as well as miR-224-5p as the most dysregulated of these miRNAs (over 400-fold). The longitudinal analysis of levels of miR-182 in sera demonstrated significant and persistent increases (5.13-fold; 95% CI: 4.59-5.70). The increase in miR-182 was detected months before any clinical symptoms were present in the animals. By the terminal time point of the study, in addition to elevated levels of serum miR-182, serum miR-122-5p was also found to be increased (>1.5-fold) in animals that developed hepatocarcinomas. Thus, using the data from an unbiased discovery approach of the tissue findings, serum miR-182 was found to track across the complex, multistage process of hepatocarcinogenesis opening an opportunity for translation to human populations.