miRNA-mediated Down-regulation Research Articles

A comprehensive analysis of spermatozoal RNA elements in idiopathic infertile males undergoing fertility treatment

Current approaches to diagnosing male infertility inadequately assess the complexity of the male gamete. Beyond the paternal haploid genome, spermatozoa also deliver coding and non-coding RNAs to the oocyte. While sperm-borne RNAs have demonstrated potential involvement in embryo development, the underlying mechanisms remain unclear. In this study, 47 sperm samples from normozoospermic males undergoing fertility treatment using donor oocytes were sequenced and analyzed to evaluate associations between sperm RNA elements (exon-sized sequences) and blastocyst progression. A total of 366 RNA elements (REs) were significantly associated with blastocyst rate (padj < 0.05), some of which were linked to genes related to critical developmental processes, including mitotic spindle formation and both ectoderm and mesoderm specification. Of note, 27 RE-associated RNAs are predicted targets of our previously reported list of developmentally significant miRNAs. Inverse RE-miRNA expression patterns were consistent with miRNA-mediated down-regulation. This study provides a comprehensive set of REs which differ by the patient’s ability to produce blastocysts. This knowledge can be leveraged to improve clinical screening of male infertility and ultimately reduce time to pregnancy.

MIRELLA: a mathematical model explains the effect of microRNA-mediated synthetic genes regulation on intracellular resource allocation.

Competition for intracellular resources, also known as gene expression burden, induces coupling between independently co-expressed genes, a detrimental effect on predictability and reliability of gene circuits in mammalian cells. We recently showed that microRNA (miRNA)-mediated target downregulation correlates with the upregulation of a co-expressed gene, and by exploiting miRNAs-based incoherent-feed-forward loops (iFFLs) we stabilise a gene of interest against burden. Considering these findings, we speculate that miRNA-mediated gene downregulation causes cellular resource redistribution. Despite the extensive use of miRNA in synthetic circuits regulation, this indirect effect was never reported before. Here we developed a synthetic genetic system that embeds miRNA regulation, and a mathematical model, MIRELLA, to unravel the miRNA (MI) RolE on intracellular resource aLLocAtion. We report that the link between miRNA-gene downregulation and independent genes upregulation is a result of the concerted action of ribosome redistribution and 'queueing-effect' on the RNA degradation pathway. Taken together, our results provide for the first time insights into the hidden regulatory interaction of miRNA-based synthetic networks, potentially relevant also in endogenous gene regulation. Our observations allow to define rules for complexity- and context-aware design of genetic circuits, in which transgenes co-expression can be modulated by tuning resource availability via number and location of miRNA target sites.

EBAG9 silencing exerts an immune checkpoint function without aggravating adverse effects

Chimeric antigen receptor (CAR) Tcells have revolutionized treatment of B cell malignancies. However, enhancing the efficacy of engineered Tcells without compromising their safety is warranted. The estrogen receptor-binding fragment-associated antigen 9 (EBAG9) inhibits release of cytolytic enzymes from cytotoxic T lymphocytes. Here, we examined the potency of EBAG9 silencing for the improvement of adoptive Tcell therapy. MicroRNA (miRNA)-mediated EBAG9 downregulation in transplanted cytolytic CD8+ Tcells (CTLs) from immunized mice improved their cytolytic competence in a tumor model. In tolerant female recipient mice that received organ transplants, a minor histocompatibility antigen was turned into a rejection antigen by Ebag9 deletion, indicating an immune checkpoint function for EBAG9. Considerably fewer EBAG9-silenced human CAR Tcells were needed for tumor growth control in a xenotransplantation model. Transcriptome profiling did not reveal additional risks regarding genotoxicity or aberrant differentiation. A single-step retrovirus transduction process links CAR or TCR expression with miRNA-mediated EBAG9 downregulation. Despite higher cytolytic efficacy, release of cytokines associated with cytokine release syndrome remains unaffected. Collectively, EBAG9 silencing enhances effector capacity of TCR- and CAR-engineered Tcells, results in improved tumor eradication, facilitates efficient manufacturing, and decreases the therapeutic dose.

MiRNA-Mediated Low Expression of EPHX3 Is Associated with Poor Prognosis and Tumor Immune Infiltration in Head and Neck Squamous Cell Carcinomas.

The aim of this study was to explore the regulatory role of epoxide hydrolase 3 (EPHX3) in head and neck squamous cell carcinoma (HNSCC) and to analyze its bioinformatic function, as well as, to screen and predict the miRNAs that can regulate EPHX3 expression in HNSCC. We examined the expression profile and prognostic potential of EPHX3 in TCGA and GTEX databases and performed functional enrichment analysis of EPHX3 using string database. Subsequently, we analyzed the regulatory role of miRNAs on EPHX3, including expression analysis, correlation analysis, and survival analysis. In addition, we also used TIMER to investigate the relationship among EPHX3 expression level, immune checkpoints, and immune infiltration in HNSCC. The results of data analysis after TGCA showed that EPHX3 is a key regulator of tumorigenesis in 13 cancers and can be used as a marker of poor prognosis in HNSCC patients. Bioinformatics analysis revealed that miR-4713-3p is a key miRNA of EPHX3 in HNSCC. Together, our findings indicate that EPHX3 exerts its anticancer effects by suppressing tumor immune checkpoint expression and immune cell infiltration. Overall, our data uncovered miRNA-mediated EPHX3 downregulation as a contributor to poor HNSCC prognosis and reduced tumor immune infiltration.

Paired miRNA and RNA sequencing provides a first insight into molecular defense mechanisms of Scapharca broughtonii during ostreid herpesvirus-1 infection

Ostreid herpesvirus 1 (OsHV-1) infection caused mortalities with relevant economic losses in bivalve aquaculture industry worldwide. Initially described as an oyster pathogen, OsHV-1 can infect other bivalve species, like the blood clam Scapharca broughtonii. However, at present, little is known about the molecular interactions during OsHV-1 infection in the blood clam. We produced paired miRNA and total RNA-seq data to investigate the blood clam transcriptional changes from 0 to 72 h after experimental infection with OsHV-1. High-throughput miRNA sequencing of 24 libraries revealed 580 conserved and 270 new blood clam miRNAs, whereas no genuine miRNA was identified for OsHV-1. Total 88–203 differently expressed miRNAs were identified per time point, mostly up-regulated and mainly targeting metabolic pathways. Most of the blood clam mRNAs, in contrast, were down-regulated up to 60 h post-injection, with the trend analysis revealing the activation of immune genes only when comparing the early and latest stage of infection. Taken together, paired short and long RNA data suggested a miRNA-mediated down-regulation of host metabolic and energetic processes as a possible antiviral strategy during early infection stages, whereas antiviral pathways appeared upregulated only at late infection.

Amylin-mediated regulation of LRP1 by miR-103/107 impairs β-amyloid efflux.

To determine whether systemic pancreatic amylin dyshomeostasis impairs the efflux of amyloid-β (Aβ) across the blood-brain barrier (BBB), we studied cerebral microvessels in humans and a rat model of pancreatic amylin dyshomeostasis, and evaluated the effect of human amylin in an in vitro BBB model. Brain sections from Alzheimer's Disease (AD) and cognitively unimpaired individuals were co-stained with anti-Aβ and anti-amylin antibodies. In vivo analyses of Aβ efflux across the BBB were carried out in aged rats that express amyloid-forming human amylin in pancreatic β-cells and littermates expressing non-amyloidogenic rat amylin. We also used an in vitro BBB model of Aβ transcytosis in which the endothelial cell monolayer was exposed to amylin-mediated stress to determine whether amylin stress downregulates LRP1, the Aβ efflux transporter. This allowed us to use pharmacology to rescue the endothelial LRP1 RESULT: In human AD brains, Aβ accumulation within the perivascular space frequently co-localizes with deposits of amylin in the vessel wall. In rats with pancreatic expression of amyloid-forming human amylin, the high blood levels of human amylin promote amylin deposition in brain capillaries, increase brain Aβ level, lower plasma-to-brain Aβ ratio and suppress expression of LRP1 protein. In vitro BBB model experiment revealed that amylin-induced stress downregulates LRP1 in endothelial cells through a miRNA-based translational repression mechanism. High blood human amylin levels cause cerebral microvascular dysfunction and interferes with Aβ efflux across the BBB through miRNA-mediated LRP1 downregulation. Lowering blood amylin level in early AD could improve Aβ clearance from the brain.

Landscape of tissue-specific RNA Editome provides insight into co-regulated and altered gene expression in pigs (Sus-scrofa)

ABSTRACT RNA editing generates genetic diversity in mammals by altering amino acid sequences, miRNA targeting site sequences, influencing the stability of targeted RNAs, and causing changes in gene expression. However, the extent to which RNA editing affect gene expression via modifying miRNA binding site remains unexplored. Here, we first profiled the dynamic A-to-I RNA editome across tissues of Duroc and Luchuan pigs. The RNA editing events at the miRNA binding sites were generated. The biological function of the differentially edited gene in skeletal muscle was further characterized in pig muscle-derived satellite cells. RNA editome analysis revealed a total of 171,909 A-to-I RNA editing sites (RESs), and examination of its features showed that these A-to-I editing sites were mainly located in SINE retrotransposons PRE-1/Pre0_SS element. Analysis of differentially edited sites (DESs) revealed a total of 4,552 DESs across tissues between Duroc and Luchuan pigs, and functional category enrichment analysis of differentially edited gene (DEG) sets highlighted a significant association and enrichment of tissue-developmental pathways including TGF-beta, PI3K-Akt, AMPK, and Wnt signaling pathways. Moreover, we found that RNA editing events at the miRNA binding sites in the 3′-UTR of HSPA12B mRNA could prevent the miRNA-mediated mRNA downregulation of HSPA12B in the muscle-derived satellite (MDS) cell, consistent with the results obtained from the Luchuan skeletal muscle. This study represents the most systematic attempt to characterize the significance of RNA editing in regulating gene expression, particularly in skeletal muscle, constituting a new layer of regulation to understand the genetic mechanisms behind phenotype variance in animals. Abbreviations: A-to-I: Adenosine-to-inosine; ADAR: Adenosine deaminase acting on RNA; RES: RNA editing site; DEG: Differentially edited gene; DES: Differentially edited site; FDR: False discovery rate; GO: Gene Ontology; KEGG: Kyoto Encyclopaedia of Genes and Genomes; MDS cell: musclederived satellite cell; RPKM: Reads per kilobase of exon model in a gene per million mapped reads; UTR: Untranslated coding regions

A distinct metabolic response characterizes sensitivity to EZH2 inhibition in multiple myeloma

Multiple myeloma (MM) is a heterogeneous haematological disease that remains clinically challenging. Increased activity of the epigenetic silencer EZH2 is a common feature in patients with poor prognosis. Previous findings have demonstrated that metabolic profiles can be sensitive markers for response to treatment in cancer. While EZH2 inhibition (EZH2i) has proven efficient in inducing cell death in a number of human MM cell lines, we hereby identified a subset of cell lines that despite a global loss of H3K27me3, remains viable after EZH2i. By coupling liquid chromatography-mass spectrometry with gene and miRNA expression profiling, we found that sensitivity to EZH2i correlated with distinct metabolic signatures resulting from a dysregulation of genes involved in methionine cycling. Specifically, EZH2i resulted in a miRNA-mediated downregulation of methionine cycling-associated genes in responsive cells. This induced metabolite accumulation and DNA damage, leading to G2 arrest and apoptosis. Altogether, we unveiled that sensitivity to EZH2i in human MM cell lines is associated with a specific metabolic and gene expression profile post-treatment.

A novel feedback loop between high MALAT-1 and low miR-200c-3p promotes cell migration and invasion in pancreatic ductal adenocarcinoma and is predictive of poor prognosis

BackgroundIt was demonstrated that long non-coding RNAs occupied an important position in tumor pathogenesis and progression. We have previously found that the metastasis-associated lung adenocarcinoma transcript 1 (MALAT-1) promotes cell proliferation and metastases in pancreatic ductal adenocarcinoma (PDAC). The present study was aimed to discuss the underlying mechanisms.MethodsBioinformatics method was used to identify the miRNA target of MALAT-1. Expressions of relative genes were assessed by quantitative real-time PCR and western blotting, respectively. Sulforhodamine B assay and Transwell assay were employed to detect cell proliferation, migration and invasion, respectively. Moreover, RNA immunoprecipitation was performed to determine whether RNA-induced silencing complex contained MALAT-1 and its potential binding miRNA. Luciferase assays was used to confirm potential binding site.ResultsBioinformatics search predicted that miR-200c-3p was a direct target of MALAT-1. Further, we found a reciprocal suppression between MALAT-1 and miR-200c-3p expression. In terms of mechanisms, high MALAT-1 and low miR-200c-3p may form a novel feedback loop. On the one hand, MALAT-1 functioned as a competing endogenous RNA to suppress miR-200c-3p expression, leading to upregulation of ZEB1 expression. On the other hand, miR-200c-3p inhibited the level of MALAT-1 expression was in a way similar to miRNA-mediated downregulation of target genes. Clinical data further indicated that MALAT-1 and ZEB1 expression was negatively correlated with miR-200c-3p transcript level of PDAC tissues. There was a positive correlation between MALAT-1 and ZEB1 level. MALAT-1 (high)/miR-200c-3p (low) correlated with shorter overall survival of PDAC patients. Multivariate analysis revealed that both MALAT-1 and miR-200c-3p levels were independent prognostic factors.ConclusionOur findings firstly revealed a novel feedback loop between high MALAT-1 and low miR-200c-3p. Targeting the feedback loop between high MALAT-1 and low miR-200c-3p will be a therapeutic strategy for PDAC.

Analysis of MicroRNA-mRNA Interactions in Stem Cell-Enriched Fraction of Oral Squamous Cell Carcinoma.

This study is an integrated analysis of the transcriptome profile microRNA (miRNA) and its experimentally validated mRNA targets differentially expressed in the tumorigenic stem-like fraction of oral squamous cell carcinoma (OSCC). We had previously reported the coexistence of multiple drug-resistant tumorigenic fractions, termed side population (SP1, SP2, and MP2), and a nontumorigenic fraction, termed main population (MP1), in oral cancer. These fractions displayed a self-renewal, regenerative potential and expressed known stemness-related cell surface markers despite functional differences. Flow cytometrically sorted pure fractions of SP1 and MP1 cells were subjected to differential expression analysis of both mRNAs and miRNAs. A significant upregulation of genes associated with inflammation, cell survival, cell proliferation, drug transporters, and antiapoptotic pathways, in addition to enhanced transcriptome reprogramming mediated by DNA–histone binding proteins and pattern recognition receptor-mediated signaling, was found to play a crucial role in the transformation of the nontumorigenic MP1 fraction to the tumorigenic SP1 fraction. We also identified several differentially expressed miRNAs that specifically target genes distinctive of tumorigenic SP1 fraction. miRNA-mediated downregulation of stemness-associated markers CD44 and CD147 and upregulation of CD151 may also account for the emergence and persistence of multiple tumorigenic stem cell fractions with varying degrees of malignancy. The phenotypic switch of cancer cells to stem-like OSCC cells mediated by transcriptomal regulation is effectual in addressing biological tumor heterogeneity and subsequent therapeutic resistance leading to a minimal residual disease (MRD) condition in oral cancer. A detailed study of the interplay of miRNAs, mRNA, and the cellular phases involved in the gradual transition of nontumorigenic cancer cells to tumorigenic stem-like cells in solid tumors would enable detection and development of a treatment regimen that targets and successfully eliminates multiple, drug-resistant fractions of cancer cells.

A miR-SNP biomarker linked to an increased lung cancer survival by miRNA-mediated down-regulation of FZD4 expression and Wnt signaling

Through a new hypothesis-driven and microRNA-pathway-based SNP (miR-SNP) association study we identified a novel miR-SNP (rs713065) in the 3′UTR region of FZD4 gene linked with decreased risk of death in early stage NSCLC patients. We determined biological function and mechanism of action of this FZD4-miR-SNP biomarker in a cellular platform. Our data suggest that FZD4-miR-SNP loci may significantly influence overall survival in NSCLC patients by specifically interacting with miR-204 and modulating FZD4 expression and cellular function in the Wnt-signaling-driven tumor progression. Our findings are bridging the gap between the discovery of epidemiological SNP biomarkers and their biological function and will enable us to develop novel therapeutic strategies that specifically target epigenetic markers in the oncogenic Wnt/FZD signaling pathways in NSCLC.

Bypassing miRNA-mediated gene regulation under drought stress: alternative splicing affects CSD1 gene expression.

The binding site for miR398 in an isoform of Cu/Zn superoxide dismutase (CSD1) is eliminated by alternative splicing to bypass miR398-mediated gene down-regulation under drought stress. MicroRNA (miRNA) binding sites (MBSs) are frequently interrupted by introns and therefore require proper splicing to generate functional MBSs in target transcripts. MBSs can also be excluded during splicing of pre-messenger RNA, leading to different regulation among isoforms. Previous studies have shown that levels of Cu/Zn superoxide dismutase (CSD) are down-regulated by miR398. In this study, sequences and transcript levels of peanut CSD1 isoforms (AhCSD1-1, AhCSD1-2.1, and AhCSD1-2.2) were analyzed under the drought stress. Results demonstrated that a miR398 binding site is eliminated in AhCSD1-2.2 as a consequence of alternative splicing, which bypasses miRNA-mediated down-regulation under drought stress. This alternative isoform was not only identified in peanut but also in soybean and Arabidopsis. In addition, transgenic Arabidopsis plants expressing AhCSD1 were more tolerant to osmotic stress. We hypothesize that the level of AhCSD1 is increased to allow diverse plant responses to overcome environmental challenges even in the presence of increased miR398 levels. These findings suggest that studies on the role of alternatively spliced MBSs affecting transcript levels are important for understanding plant stress responses.

MiR-380-5p-mediated repression of TEP1 and TSPYL5 interferes with telomerase activity and favours the emergence of an \u201cALT-like\u201d phenotype in diffuse malignant peritoneal mesothelioma cells

BackgroundUnderstanding the molecular/cellular underpinnings of diffuse malignant peritoneal mesothelioma (DMPM), a fatal malignancy with limited therapeutic options, is of utmost importance for the fruitful management of the disease. In this context, we previously found that telomerase activity (TA), which accounts for the limitless proliferative potential of cancer cells, is prognostic for disease relapse and cancer-related death in DMPM patients. Consequently, the identification of factors involved in telomerase activation/regulation may pave the way towards the development of novel therapeutic interventions for the disease. Here, the capability of miR-380-5p, a microRNA negligibly expressed in telomerase-positive DMPM clinical specimens, to interfere with telomerase-mediated telomere maintenance and, hence, with cancer cell growth was assessed on preclinical models of DMPM.MethodsDMPM cells were transfected with a miR-380-5p synthetic precursor, and the effects of miRNA replacement were evaluated in terms of growing capability, induction of apoptosis and interference with TA. Reiterated weekly transfections were also performed in order to analyse the phenotype arising upon prolonged miR-380-5p reconstitution in DMPM cells.ResultsThe ectopic expression of miR-380-5p elicited a remarkable inhibition of TA and resulted in DMPM cell growth impairment and apoptosis induction. In particular, we demonstrated for the first time that these effects were the result of a molecular circuitry converging on telomerase associated protein 1 (TEP1), where the miRNA was able to target the gene both directly in unconventional targeting modality and indirectly via p53 accumulation consequent to miRNA-mediated downregulation of testis-specific protein, Y-encoded-like 5 gene. Moreover, miR-380-5p did not cause telomere attrition and cell growth arrest in long-term DMPM transfectants, which in turn showed slightly elongated telomeres and molecular features (e.g. c-circle DNA and reduced expression levels of chromatin remodeler ATRX) resembling an alternative lengthening of telomeres (ALT) phenotype.ConclusionsmiR-380-5p interferes with TA in DMPM cells by targeting TEP1. Notably, in the long-term setting, miR-380-5p-mediated impairment of TA did not result in telomere attrition. Instead, a phenotype reminiscent of ALT emerged in DMPM cells as possible compensatory pathway that safeguards DMPM cell growth, an event that may be regarded as a potential resistance mechanism to anticancer therapies based on telomerase inhibitors.

MicroRNA-Mediated Down-Regulation of Apoptosis Signal-Regulating Kinase 1 (ASK1) Attenuates the Apoptosis of Human Mesenchymal Stem Cells (MSCs) Transplanted into Infarcted Heart.

Stem cell therapy using adult stem cells, such as mesenchymal stem cells (MSCs) has produced some promising results in treating the damaged heart. However, the low survival rate of MSCs after transplantation is still one of the crucial factors that limit the therapeutic effect of stem cells. In the damaged heart, oxidative stress due to reactive oxygen species (ROS) production can cause the death of transplanted MSCs. Apoptosis signal-regulating kinase 1 (ASK1) has been implicated in the development of oxidative stress-related pathologic conditions. Thus, we hypothesized that down-regulation of ASK1 in human MSCs (hMSCs) might attenuate the post-transplantation death of MSCs. To test this hypothesis, we screened microRNAs (miRNAs) based on a miRNA-target prediction database and empirical data and investigated the anti-apoptotic effect of selected miRNAs on human adipose-derived stem cells (hASCs) and on rat myocardial infarction (MI) models. Our data indicated that miRNA-301a most significantly suppressed ASK1 expression in hASCs. Apoptosis-related genes were significantly down-regulated in miRNA-301a-enriched hASCs exposed to hypoxic conditions. Taken together, these data show that miRNA-mediated down-regulation of ASK1 protects MSCs during post-transplantation, leading to an increase in the efficacy of MSC-based cell therapy.

Epstein–Barr virus microRNAs reduce immune surveillance by virus-specific CD8+ T cells

Infection with Epstein-Barr virus (EBV) affects most humans worldwide and persists life-long in the presence of robust virus-specific T-cell responses. In both immunocompromised and some immunocompetent people, EBV causes several cancers and lymphoproliferative diseases. EBV transforms B cells in vitro and encodes at least 44 microRNAs (miRNAs), most of which are expressed in EBV-transformed B cells, but their functions are largely unknown. Recently, we showed that EBV miRNAs inhibit CD4+ T-cell responses to infected B cells by targeting IL-12, MHC class II, and lysosomal proteases. Here we investigated whether EBV miRNAs also counteract surveillance by CD8+ T cells. We have found that EBV miRNAs strongly inhibit recognition and killing of infected B cells by EBV-specific CD8+ T cells through multiple mechanisms. EBV miRNAs directly target the peptide transporter subunit TAP2 and reduce levels of the TAP1 subunit, MHC class I molecules, and EBNA1, a protein expressed in most forms of EBV latency and a target of EBV-specific CD8+ T cells. Moreover, miRNA-mediated down-regulation of the cytokine IL-12 decreases the recognition of infected cells by EBV-specific CD8+ T cells. Thus, EBV miRNAs use multiple, distinct pathways, allowing the virus to evade surveillance not only by CD4+ but also by antiviral CD8+ T cells.

Abstract 1999: Regulation of the oncogenic, invasion-promoting transcription factor myeloid zinc finger-1 (MZF1) in breast cancer by microRNAs

Abstract INTRODUCTION: Myeloid Zinc Finger 1 (MZF1) is a transcription factor that is normally involved in myeloid differentiation. MZF1 can also be found in epithelial cancers, where it functions as an invasion and metastasis promoting oncogene. MZF1 is a central node of the invasive signaling network activated by HER2/ErbB2 in breast cancer, where MZF1 mobilizes and activates lysosomes and increases the expression of cysteine cathepsin B to promote invasion and metastasis. Thus, maintaining the sufficient expression level of MZF1 is important for the invasive signaling of breast cancer cells. RESULTS AND EXPERIMETAL PROCHEDURES: Here we show that MZF1 is essential for the invasion of breast cancer cells in 3-dimensional cultures. We also describe a possible mechanism that regulates MZF1 levels in breast cancer. By using available micro-RNA (miRNA) binding site prediction programs (www.microrna.org/), specific microRNA mimics, corresponding miRNA inhibitors e.g. locked nucleic acids, luciferase reporter assays, immunofluorescense, quantitative PCR and 3-dimensional invasion assays we show that some breast cancer specific miRNAs can regulate MZF1 RNA and protein levels and revert the malignant and invasive cellular phenotype of breast cancer cells by altering the invasion promoting functions of lysosomes. These results are supported by the analysis of breast cancer patient data from the cancer genome atlas (http://cancergenome.nih.gov) showing that MZF1 expression correlates negatively with the expression of the identified miRNAs, when using data collected from over 600 primary breast cancer tumors. SUMMARY: This study shows that MZF1 is an oncogene whose sufficient expression levels are central for breast cancer cell invasion and whose specific miRNA-mediated downregulation can inhibit breast cancer malignancy by modifying the expression of its lysosomal target genes. CONCLUSION: Cancer-associated upregulation of MZF1 increases the breast cancer malignancy. Thus finding ways to downregulate MZF1 expression or inhibit its activity can be beneficial for breast cancer therapy. Citation Format: Tuula Kallunki, Siri A. Tvingsholm, Knut K. Bundgaard Clemmensen, Ditte M. Brix, Bo Rafn, José Moreira, Lisa Frankel, Anders Lund, Riku Louhimo, Sampsa Hautaniemi, Irina Gromova, Marja Jäättelä. Regulation of the oncogenic, invasion-promoting transcription factor myeloid zinc finger-1 (MZF1) in breast cancer by microRNAs. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1999.

Artificial miRNA-mediated down-regulation of two monolignoid biosynthetic genes (C3H and F5H) cause reduction in lignin content in jute.

Artificial microRNAs (amiRNA) provide a new feature in the gene silencing era. Concomitantly, reducing the amount of lignin in fiber-yielding plants such as jute holds significant commercial and environmental potential, since this amount is inversely proportional to the quality of the fiber. The present study aimed at reducing the lignin content in jute, by introducing amiRNA based vectors for down-regulation of two monolignoid biosynthetic genes of jute, coumarate 3-hydroxylase (C3H) and ferulate 5-hydroxylase (F5H). The transgenic lines of F5H-amiRNA and C3H-amiRNA showed a reduced level of gene expression, which resulted in about 25% reduction in acid insoluble lignin content for whole stem and 12-15% reduction in fiber lignin as compared to the non-transgenic plants. The results indicate successful F5H-amiRNA and C3H-amiRNA transgenesis for lignin reduction in jute. This is likely to have far-reaching commercial implications and economic acceleration for jute producing countries.

MicroRNA regulation of F-box proteins and its role in cancer.

MicroRNAs (miRNAs) are small endogenous non-coding RNAs, which play critical roles in cancer development by suppressing gene expression at the post-transcriptional level. In general, oncogenic miRNAs are upregulated in cancer, while miRNAs that act as tumor suppressors are downregulated, leading to decreased expression of tumor suppressors and upregulated oncogene expression, respectively. F-box proteins function as the substrate-recognition components of the SKP1-CUL1-F-box (SCF)-ubiquitin ligase complex for the degradation of their protein targets by the ubiquitin-proteasome system. Therefore F-box proteins and miRNAs both negatively regulate target gene expression post-transcriptionally. Since each miRNA is capable of fine-tuning the expression of multiple target genes, multiple F-box proteins may be suppressed by the same miRNA. Meanwhile, one F-box proteins could be regulated by several miRNAs in different cancer types. In this review, we will focus on miRNA-mediated downregulation of various F-box proteins, the resulting stabilization of F-box protein substrates and the impact of these processes on human malignancies. We provide insight into how the miRNA: F-box protein axis may regulate cancer progression and metastasis. We also consider the broader role of F-box proteins in the regulation of pathways that are independent of the ubiquitin ligase complex and how that impacts on oncogenesis. The area of miRNAs and the F-box proteins that they regulate in cancer is an emerging field and will inform new strategies in cancer treatment.

Data supporting the role of the non-glycosylated isoform of MIC26 in determining cristae morphology.

Membrane architecture is crucially important for mitochondrial function and integrity. The MICOS complex is located at crista junctions and determines cristae membrane morphology and the formation of crista junctions. Here we provide data of the bona fide MICOS subunit MIC26 for determining cristae morphology. MiRNA-mediated downregulation of MIC26 results in higher protein levels of MIC27 and in lower levels of Mic10. Using a miRNA-resistant form to MIC26 we show that this effect is specific to MIC26. Our data further demonstrate that depletion of MIC26 primarily affects the level of the 22 kDa mitochondrial isoform of MIC26 but not the amount of the secreted 55 kDa isoform of MIC26. Depletion of MIC27, however, increases secretion of the latter isoform. Overexpression of a myc-tagged version of MIC26 resulted in altered cristae morphology with swollen and partly vesicular cristae-structures.

Peptides from Nme2 Are Preferentially Expressed By Chronic Phase CML Cells, Recognized By T Cells and Restricted By the Most Frequent HLA-Antigens

Nme2 (non metastasis protein 2) is a nucleoside diphosphate kinase that plays multiple roles in signalling and metabolism. We previously identified Nme2 as a tumor antigen in chronic myeloid leukaemia (CML) and found Nme2 protein over-expression to be a universal and specific feature of Bcr/Abl+ cells in chronic-phase of the disease. Nme2 up-regulation in Bcr/Abl+ cells is post-transcriptional and is reversed by TKI treatment. Furthermore, the IL-3 independence induced by Bcr/Abl transfection of Ba/F3 cells is also accompanied by Nme2 over-expression and is reversed by specific miRNA-mediated down-regulation of Nme2, suggesting that Nme2 contributes to Bcr/Abl driven leukemogenesis. Here, we have investigated the potential of Nme2 as a target for CML specific immunotherapy by assessing it’s antigenicity in common HLA backgrounds.Peripheral blood mononuclear cells (PBMCs) were obtained from 40 patients with CML and 24 healthy donors who carried the common HLA-A02 (n=21/7); A03 (n=12/8) and A24 (n=8/9) antigens. Together, these represent the most common HLA types in the Caucasian population. Samples were obtained before (n = 13) and after (n = 36) hematopoietic stem cell transplantation (HCT) and Nme2 specific cytotoxic T lymphocytes (CTL) were generated using artificial antigen presenting cells (aAPC) engineered to express both Nme2 and the appropriate HLA-A antigen. PBMC were primed with aAPC and then re-stimulated weekly. Following CD8+ T-cell selection on day 14, IFNγ production in response to Nme2 expressing stimulator cells was evaluated in Elispot assays. In addition Nme2 reactivity was investigated in peripheral blood cells of CML patients by Elispot assays at various time points up to 10 years after HCT.The frequency of Nme2 specific T cells was significantly higher in CML patients pre HCT (39.3 specific T cells/105 CD8+ cells, p=0.004) than in healthy donors (2.17 specific T cells/105 CD8+ cells). A further rise in specific T cell response was detected in CML patients post HCT (142 specific T cells/105 CD8+ cells, p=0.0006), with a significant increase being evident by day +50 after HCT. The subsequent activity varies, with a weakly pronounced second peak occurring around 3 years post-transplant. However, Nme2 specific T cells persisted over the entire observation period with a significant Nme2 specific T cell response still being detectable nearly 10 years post transplant. The highest Nme2 specific T cell activity was found in HLA-A03 positive patients (187 T cells/105 CD8+ cells) and the lowest in the HLA-A02 background (102 T cells/105 CD8+ cells, p=0.00001). Restriction by HLA-A24 was associated with an intermediate activity (141 Nme2 specific T cells/105 CD8+ cells). We identified 8 patients in which an increase of Bcr-Abl transcript level from 0% Bcr-Abl/Abl to a detectable amount (0.28%, range 0.001 to 5.017% Bcr-Abl/Abl) was observed. In all cases, a transient increase in Nme2 reactive T cells (2.7 fold, p=0.007) was associated with re-entry into molecular remission. Furthermore, Nme2 specific T cells were lower before relapse (88 T cells/105 CD8+ cells) than in patients with long lasting molecular remission (186 T cells/105 CD8+ cells, p=0.026).Finally, we successfully generated Nme2 specific CTLs from healthy donors (4/5) as well as from patients with CML who had received HCT (10/10). CTLs showed a mean expansion rate of 23 (healthy donors) to 30 fold (CML patients) and HLA class I restricted Nme2 specific recognition. Partially HLA matched, primary CML cells were targeted by these Nme2 specific CTLs (6/6), regardless of the presence of the T315I Bcr/Abl mutation that bestows resistance to tyrosine kinase inhibitors (TKI).In summary, we show here that Nme2 is a strong inducer of immune response in transplanted CML patients carrying common HLA class I alleles, implying that the immune response to Nme2 may be involved in the GvL effect post HCT. Our results suggest that Nme2 specific CTLs may be of therapeutic relevance in eradicating the residual leukemic cells after therapy with TKI or HCT. DisclosuresNo relevant conflicts of interest to declare.