Modulation Of miRNAs Research Articles

Identification of Differentially Expressed miRNAs in Colorado Potato Beetles (Leptinotarsa decemlineata (Say)) Exposed to Imidacloprid.

The Colorado potato beetle (Leptinotarsa decemlineata (Say)) is a significant pest of potato plants that has been controlled for more than two decades by neonicotinoid imidacloprid. L. decemlineata can develop resistance to this agent even though the molecular mechanisms underlying this resistance are not well characterized. MicroRNAs (miRNAs) are short ribonucleic acids that have been linked to response to various insecticides in several insect models. Unfortunately, the information is lacking regarding differentially expressed miRNAs following imidacloprid treatment in L. decemlineata. In this study, next-generation sequencing and quantitative real-time polymerase chain reaction (qRT-PCR) were used to identify modulated miRNAs in imidacloprid-treated versus untreated L. decemlineata. This approach identified 33 differentially expressed miRNAs between the two experimental conditions. Of interest, miR-282 and miR-989, miRNAs previously shown to be modulated by imidacloprid in other insects, and miR-100, a miRNA associated with regulation of cytochrome P450 expression, were significantly modulated in imidacloprid-treated beetles. Overall, this work presents the first report of a miRNA signature associated with imidacloprid exposure in L. decemlineata using a high-throughput approach. It also reveals interesting miRNA candidates that potentially underly imidacloprid response in this insect pest.

Epigenetics of bone diseases

Histone deacetylation, DNA methylation, and micro-RNAs (miRNAs) are the three main epigenetic mechanisms that regulate gene expression. All the physiological processes involved in bone remodeling are tightly regulated by epigenetic factors. This review discusses the main epigenetic modifications seen in tumoral and non-tumoral bone diseases, with emphasis on miRNAs. The role for epigenetic modifications of gene expression in the most common bone diseases is illustrated by drawing on the latest publications in the field. In multifactorial bone diseases such as osteoporosis, many epigenetic biomarkers, either alone or in combination, have been associated with bone mineral density or suggested to predict osteoporotic fractures. In addition, treatments designed to modulate bone remodeling by selectively targeting the function of specific miRNAs are being evaluated. Advances in the understanding of epigenetic regulation shed new light on the pathophysiology of other non-tumoral bone diseases, including genetic conditions inherited on a Mendelian basis. Finally, in the area of primary and metastatic bone tumors, the last few years have witnessed considerable progress in elucidating the epigenetic regulation of oncogenesis and its local interactions with bone tissue. These new data may allow the development of epigenetic outcome predictors, which are in very high demand, and of innovative therapeutic agents acting via miRNA modulation.

Influence of miR-7a and miR-24-3p on the SOX18 transcript in lung adenocarcinoma

The molecular pathogenesis of the development of non-small cell lung carcinomas (NSCLCs) is extremely complex. Understanding the molecular basis of the development of this malignant tumor may enable the use of targeted therapy, which may result in a better treatment outome for these patients. Adenocarcinoma (AC) is the most common NSCLC subtype, equally common among smokers and non-smokers, and its pathogenesis remains unknown. The SOX18 protein is an important protein that plays a role in the development of blood and lymphatic vessels during the process of embryogenesis. Recent studies have also shown that the SOX18 protein may play a significant role in tumors, including lung cancers. In the present study, we analyzed the expression of the SOX18 protein and the mRNA level in postoperative samples of AC and non-malignant lung tissues (NMLTs), and a disparity in both levels was observed. Based on our previous observations that miR-7a and miR-24-3p are able to modulate SOX18 expression in NSCLC, the main aim of this study was to verify the miRNA modulation of the SOX18 transcript with the use of the MirTrap System in established lung cancer cell lines NCI-H1703, NCI-H522 and A549. The SOX18 mRNA expression level was significantly lower in AC than that noted in the NMLTs (P<0.0001). However, the protein levels were higher in AC cases compared to levels noted in the NMLTs (P<0.0001). Additionally, correlations between the RQ values of SOX18 in NMLT and AC cases (r=0.8195, P=0.0001), and between miR-7a and miR24-3p in AC cases (r=0.4344, P=0.0016), were noted. In conclusion, we confirmed that miR-7a and miR-24-3p are more highly expressed in NMLTs than in the AC samples, and that they modulate the SOX18 transcript in NSCLC cells.

CD105 is regulated by hsa-miR-1287 and its expression is inversely correlated with osteopotential in SHED

A more accurate understanding of the molecular mechanisms and signaling pathways underpinning human mesenchymal stem cell (MSC) plasticity and differentiation properties is pivotal for accomplishing solid and diligent translation of MSC-based experimental therapeutics and clinical trials to broad clinical practice. In addition, this knowledge enables selection of MSC subpopulations with increased differentiation potential and/or use of exogenous factors to boost this potential. Here, we report that CD105 (ENG) is a predictive biomarker of osteogenic potential in two types of MSCs: stem cells from human exfoliated deciduous teeth (SHED) and human adipose-derived stem cells (hASC). We also validate that CD105 can be used to select and enrich for subpopulations of SHED and hASC with higher in vitro osteogenic potential. In addition, we show that hsa-mir-1287 regulates CD105 expression, and propose that fine-tuning hsa-mir-1287 levels could be used to control osteopotential in SHED. These findings provide better discernment of the molecular bases behind MSC osteogenic plasticity and open up new perspectives to leverage osteogenic potential in MSCs by modulation of a specific miRNA.

Curcumin and Lung Cancer: the Role of microRNAs.

Lung cancer is one of the most common types of cancer worldwide and is characterized by a poor prognosis, related to both late diagnosis and lack of effective treatments. In the last years, microRNAs (miRNAs) have been demonstrated to have an important role in tumor microenvironment and immune regulation. These RNAs can be categorized into tumor-suppressor genes, such as let-7 family and miR-34, and oncogenes such as miR-221 and miR-222. Curcumin is a bioactive polyphenol that is documented to have promising anticancer activity, and to be well tolerated in humans. The present review aims to gather available evidence on the involvement of mRNAs in the therapeutic effects of curcumin against lung cancer. The anti-cancer properties of curcumin against lung cancer have been shown in both cellular and experimental models and are mediated by modulation of several molecular targets that regulate the expression of transcription factors, inflammatory cytokines, enzymes, growth factors, receptors, adhesion molecules, antiapoptotic proteins, and cell cycle proteins, leading to cell apoptosis, inhibition of cell proliferation and migration, and also chemo- and radio-sensitization of lung cancer cells. Recent studies have documented that pharmacological effects of curcumin in lung cancer are also mediated by modulation of several miRNAs, such as downregulation of oncogenic miR-21 and upregulation of oncosuppressive miR-192-5p and miR-215. Further studies are necessary to explore this very promising field and the link between regulation of oncogenic and tumor-suppressive miRNAs and putative anti-cancer properties of curcumin.

Systems genetics identifies a co-regulated module of liver microRNAs associated with plasma LDL cholesterol in murine diet-induced dyslipidemia.

Chronically altered levels of circulating lipids, termed dyslipidemia, is a significant risk factor for a number of metabolic and cardiovascular morbidities. MicroRNAs (miRNAs) have emerged as important regulators of lipid balance, have been implicated in dyslipidemia, and have been proposed as candidate therapeutic targets in lipid-related disorders including atherosclerosis. A major limitation of most murine studies of miRNAs in lipid metabolic disorders is that they have been performed in just one (or very few) inbred strains, such as C57BL/6. Moreover, although individual miRNAs have been associated with lipid phenotypes, it is well understood that miRNAs likely work together in functional modules. To address these limitations, we implemented a systems genetics strategy using the Diversity Outbred (DO) mouse population. Specifically, we performed gene and miRNA expression profiling in the livers from ~300 genetically distinct DO mice after 18 wk on either a high-fat/high-cholesterol diet or a high-protein diet. Large-scale correlative analysis of these data with a wide range of cardio-metabolic end points revealed a co-regulated module of miRNAs significantly associated with circulating low-density lipoprotein cholesterol (LDL-C) levels. The hubs of this module were identified as miR-199a, miR-181b, miR-27a, miR-21_-_1, and miR-24. In sum, we demonstrate that a high-fat/high-cholesterol diet robustly rewires the miRNA regulatory network, and we identify a small group of co-regulated miRNAs that may exert coordinated effects to control circulating LDL-C.

Micro-RNAs, Exercise and Cellular Plasticity in Humans: The Impact of Dietary Factors and Hypoxia

Physical exercise is a stress that modulates a plethora of cellular mechanisms to promote morphological and metabolic adaptations. Substantial efforts have been made to better understand the modulation of pathways involved in cell plasticity during exercise, but human explorations may be limited because invasive procedures are often required. In recent years, minimally invasive methods for the analysis of microRNAs (miRNAs) modulation in response to exercise have been developed. miRNAs are small molecules that belong to a family of non-coding RNAs. miRNAs have a significant biological impact as they control more than 60% of human genome by targeting specific messenger RNAs. Recent studies conducted in human showed that miRNAs are detectable in a variety of biological fluids such as serum, plasma, saliva, urine and tears. Both endurance and strength exercises modulate the expression of miRNAs coding for actors involved in several cellular processes related to training adaptation. In this review, we discuss recent advances on the development of methods for miRNAs detection and the impact of acute and chronic exercise on their modulation in humans. We especially highlight the most recent studies on the factors that can impact miRNAs modulation during exercise, including the mode of exercise, the nutritional status, the use of ergogenic aids, and hypoxic exposure, and present recent findings on the potential to use miRNAs as biomarkers for anti-doping control. We finally discuss the importance of considering recent data on organelle turnover-related pathways, and current limitations in order to encourage further investigations on this area.

High-throughput screening uncovers miRNAs enhancing glioblastoma cell susceptibility to tyrosine kinase inhibitors.

Glioblastoma (GBM) is a deadly and therapy resistant malignant brain tumour, characterized by an aggressive and diffuse growth pattern, which prevents complete surgical resection. Despite advances in the identification of genomic and molecular alterations that fuel the tumour, average patient survival post-diagnosis remains very low (∼14.6-months). In addition to being highly heterogeneous, GBM tumour cells exhibit high adaptive capacity to targeted molecular therapies owing to an established network of signalling cascades with functional redundancy, which provides them with robust compensatory survival mechanisms. Here, we investigated whether a multimodal strategy combining multitargeted tyrosine kinase inhibitors (MTKIs) and microRNA (miRNA) modulation could overcome the signalling pathway redundancy in GBM and, hence, promote tumour cell death. By performing a high-throughput screening, we identified a myriad of miRNAs, including those belonging to the miR-302-3p/372-3p/373-3p/520-3p family, which coordinately act with the MTKI sunitinib to decrease GBM cell viability. Two members of this family, hsa-miRNA-302a-3p and hsa-miRNA-520 b, were found to modulate the expression of receptor tyrosine kinase mediators (including AKT1, PIK3CA and SOS1) in U87 and DBTRG human GBM cells. Importantly, administration of mimics of these miRNAs with sunitinib or axitinib resulted in decreased tumour cell proliferation and enhanced cell death, whereas no significant effect was observed when coupling miRNA modulation with temozolomide, the first-line drug for GBM therapy. Overall, our results provide evidence that combining the 'horizontal' inhibition of signalling pathways promoted by MTKIs with the 'vertical' inhibition of the downstream signalling cascade promoted by hsa-miR-302a-3p and hsa-miR-520 b constitutes a promising approach towards GBM treatment.

O28 Importance of pro-inflammatory immune lymphocyte Th17 in antitumoral properties of resveratrol, a polyphenol of wine

Numerous epidemiological studies show that various polyphenols may protect against various diseases such as vascular diseases, cancers and inflammatory pathologies. One of the best known is the polyphenol resveratrol which is a trans-3,4’,5-trihydroxystilbene, which appears to be of great interest in the prevention of these pathologies. We have recently shown that resveratrol can prevent carcinogenesis via an anti-inflammatory action through a modulation of miRNA. This inflammation could also promote tumoral progression through a modulation of the immune response. Thus, the objectives of this study were to evaluate the potential effect of resveratrol in the immune response in mice with melanoma. Our results highlight that resveratrol modulates differentiation of lymphocytes Th17, which exerts protumoral activity via interleukin-17 production. Indeed, naive CD4 T cells derived from C57BL/6 mice displayed reduced capability to differentiate into Th17 cells in vitro after resveratrol treatment. Moreover in a mouse model of melanoma (B16F10), resveratrol prevented tumor growth and angiogenesis in an IL-17-dependent manner. This phenomenon could be due to a strong inhibition of the expression of the Th17-specific transcription factor Rorc. This work brings a new mechanism by which resveratrol prevents cancer related inflammation through a modulation of the immune cells and interleukin production. Acknowledgements This work is supported by the Regional Council of Burgundy and the Ligue Interregional Grand-Est contre le Cancer.

NF-κB mediated miR-130a modulation in lung microvascular cell remodeling: Implication in pulmonary hypertension

Pulmonary arterial hypertension (PAH) is a progressive pulmonary vascular disease which is associated with pulmonary arterial endothelial cells (PAEC) dysfunction and pulmonary arterial smooth muscle cells proliferation. Moreover, inflammation is contributing a critical role in EC dysfunction and remains elusive. Nuclear factor-kappa B (NF-κB) is a master transcriptional regulator in various cardiovascular pathologies; but, NF-κB's role in EC dysfunction in unknown. Our previous study using cardiac and lung specific IκBα mutant mice (3M and IKBM) showed that PAH induced right ventricular hypertrophy (RVH) was prevented in monocrotaline (MCT) treated 3M and IKBM mice, compared to the wild-type mice. Recently, microRNAs (miRNAs) have emerged as a new class of post-transcriptional regulators in vascular remodeling; but, NF-κB regulated miRNA modulation in EC dysfunction is unknown. Using miRNA array analysis, we identified miR-130a which is upregulated in MCT-induced PAH mouse model, as a possible candidate to study. We showed that overexpressing miR-130a in lung microvascular endothelial cells (MVEC) promoted activation of α-smooth muscle actin, a critical component in endothelial-to-mesenchymal transition in EC remodeling. In this study, we demonstrated that bone morphogenetic protein receptor 2 (BMPR2) was a target for miR-130a and miR-130a was regulated by NF-κB which controlled apoptosis and vascular genes in MVEC. The findings reveal that NF-κB-mediated miR-130a modulation is critical in lung vascular remodeling.

Modulation of let-7 miRNAs controls the differentiation of effector CD8 T cells

The differentiation of naive CD8 T cells into effector cytotoxic T lymphocytes upon antigen stimulation is necessary for successful antiviral, and antitumor immune responses. Here, using a mouse model, we describe a dual role for the let-7 microRNAs in the regulation of CD8 T cell responses, where maintenance of the naive phenotype in CD8 T cells requires high levels of let-7 expression, while generation of cytotoxic T lymphocytes depends upon T cell receptor-mediated let-7 downregulation. Decrease of let-7 expression in activated T cells enhances clonal expansion and the acquisition of effector function through derepression of the let-7 targets, including Myc and Eomesodermin. Ultimately, we have identified a novel let-7-mediated mechanism, which acts as a molecular brake controlling the magnitude of CD8 T cell responses.

Abstract 416: NF-kB-Mir-23a-27a: a Critical Modulator in Post-myocardial Infarction Remodeling

Myocardial infarction (MI) is one of the leading causes of death around the world. Myocardial ischemia contributes to the development of MI and initiates cardiomyocyte (CM) apoptosis, myofibroblasts differentiation, fibrosis and left ventricle (LV) remodeling leading to cardiac dysfunction. Previously, we have demonstrated the direct involvement of miRNAs (a new class of post-translational regulator) and NF-κB in LV remodeling. However, NF-κB-mediated miRNA modulation and miRNA/gene networks in post-MI remodeling remain elusive. Furthermore, with an emerging interest to combine cell transplantation with gene therapy, mesenchymal stem cells (MSC) are considered most beneficial of the stem cells in regenerative medicine. We have a paucity of data in genetically modified MSC on their mobilization within infarcted myocardium. We identified a panel of novel dysregulated miRNAs in the wild type (WT) mice subjected to MI using conventional miRNA array. These miRNAs were restored in cardiac-specific IκBα triple-mutant mice (3M, resistant to NF-κB activation) mice indicated NF-κB-dependent regulation. Among them, miR-23a and miR-27a were significantly upregulated in MI. Our study has identified PPARγ-GSK3β-Bcl 2 -axis, a bona-fide target for miR-23a/-27a after unbiased in vitro screening. Our hypothesis is that NF-κB-dependent miR-23a/-27a is a pathogenic niche, exacerbates post-MI remodeling through several target pathways; and inhibition of NF-κB, miR-23a/-27a and transplantation of 3M-MSC mitigates the cardiac damage and abrogates the cardiac damage by restoring PPARγ-GSK3β-Bcl 2 -axis. Inhibition of NF-κB normalized miR-23a/-27a expression and reduced CM death in hypoxia/ reoxygenation (H/R) model. Our data also indicated that miR-23a is a key regulator in simulated H/R-induced injury. Inhibition of miR-23a showed reduction of cell death and improved mitochondrial function in H/R model. Interestingly, 3M-MSC showed significant reduction in apoptosis, inflammation and oxidative stress in H/R-induced CM injury, compared to WT-MSC. Our findings conclude that miR-23a/-27a could be a triggering factor and 3M-MSC provides a better protection in post-MI remodelling indicate new mechanistic information for therapeutic benefit.

Abstract 106: microRNA-33a Regulates Myocardin Expression and Attenuates Cardiac Remodeling in Renal Artery Ligation Model of Heart Failure

Myocardin (MYOCD), a cardiac specific transcriptional co-activator is up-regulated in heart failure (HF). Up-regulation of MYOCD expression has been proposed to be an important adaptive response in cardiac remodelling. However, molecular mechanisms contributing to increased cardiac MYOCD expression in HF are not known. The goal of this study was to identify microRNA(s) regulating cardiac MYOCD expression and to study the effect of cardiac modulation of MYOCD specific miRNA in an animal model of HF. miRNA(s) targeting MYOCD were identified using in silico approach and validated by 3’-UTR luciferase reporter assay. Cardiac expression of miRNA was measured in endomyocardial biopsies from idiopathic DCM (IDCM) patients, renal artery ligation rat model of HF (RAL) and in Ang II treated cardiomyocytes by real-time PCR. miRNA-33a, miRNA-33b, miRNA-139 and miRNA-542 were identified with MYOCD as putative target. Cardiac expression of miRNA-33a and miRNA-33b was significantly decreased, whereas expression of miRNA-139 and miRNA-542 was not altered in IDCM. miRNA-33a expression was also decreased in RAL and in Ang II treated cardiomyocytes. Luciferase assay confirmed MYOCD as target gene for miRNA-33a. miRNA-33a overexpression significantly decreased expression of MYOCD, ANP and fibrotic genes in Ang II treated cardiomyocytes. Cardiac specific delivery of miRNA-33a, using a homing peptide conjugated siRNA, attenuated cardiac hypertrophy and fibrosis, decreased expression of ANP, β-MHC and fibrotic genes and ameliorated the impaired diastolic dysfunction in RAL. Our results provide the first evidence that miRNA-33a regulates MYOCD expression and cardiac specific augmentation of miRNA-33a attenuated cardiac remodelling and partially restored left ventricular function. Our results suggest miR-33a as a potential therapeutic target in reversal of cardiac remodelling and improvement in heart function in HF.

Co-Expression Network and Pathway Analyses Reveal Important Modules of miRNAs Regulating Milk Yield and Component Traits

Co-expression network analyses provide insights into the molecular interactions underlying complex traits and diseases. In this study, co-expression network analysis was performed to detect expression patterns (modules or clusters) of microRNAs (miRNAs) during lactation, and to identify miRNA regulatory mechanisms for milk yield and component traits (fat, protein, somatic cell count (SCC), lactose, and milk urea nitrogen (MUN)) via miRNA target gene enrichment analysis. miRNA expression (713 miRNAs), and milk yield and components (Fat%, Protein%, lactose, SCC, MUN) data of nine cows at each of six different time points (day 30 (D30), D70, D130, D170, D230 and D290) of an entire lactation curve were used. Four modules or clusters (GREEN, BLUE, RED and TURQUOISE) of miRNAs were identified as important for milk yield and component traits. The GREEN and BLUE modules were significantly correlated (|r| > 0.5) with milk yield and lactose, respectively. The RED and TURQUOISE modules were significantly correlated (|r| > 0.5) with both SCC and lactose. In the GREEN module, three abundantly expressed miRNAs (miR-148a, miR-186 and miR-200a) were most significantly correlated to milk yield, and are probably the most important miRNAs for this trait. DDR1 and DDHX1 are hub genes for miRNA regulatory networks controlling milk yield, while HHEX is an important transcription regulator for these networks. miR-18a, miR-221/222 cluster, and transcription factors HOXA7, and NOTCH 3 and 4, are important for the regulation of lactose. miR-142, miR-146a, and miR-EIA17-14144 (a novel miRNA), and transcription factors in the SMAD family and MYB, are important for the regulation of SCC. Important signaling pathways enriched for target genes of miRNAs of significant modules, included protein kinase A and PTEN signaling for milk yield, eNOS and Noth signaling for lactose, and TGF β, HIPPO, Wnt/β-catenin and cell cycle signaling for SCC. Relevant enriched gene ontology (GO)-terms related to milk and mammary gland traits included cell differentiation, G-protein coupled receptor activity, and intracellular signaling transduction. Overall, this study uncovered regulatory networks in which miRNAs interacted with each other to regulate lactation traits.

Leptin induction following irradiation is a conserved feature in mammalian epithelial cells and tissues

Purpose: Leptin (LEP) is a peptide hormone with multiple physiological functions. Besides its systemic actions, it has important peripheral roles such as a mitogen action on keratinocytes following skin lesions. We previously showed that LEP mRNA is significantly induced in response to neutron irradiation in mouse skin and that the protein increases in the irradiated epidermis and in the related subcutaneous adipose tissue. In this work, we investigated the post-transcriptional regulation of LEP by miRNAs and the conservation of LEP’s role in radiation response in human cells.Methods: We used microarray analysis and real-time polymerase chain reaction (RT-PCR) to analyze modulation of miRNAs potentially targeting LEP in mouse skin following irradiation and bioinformatic analysis of transcriptome of irradiated human cell lines and cancer tissues from radiotherapy-treated patients to evaluate LEP expression.Results and conclusions: We show that a network of miRNAs potentially targeting LEP mRNA is modulated in irradiated mouse skin and that LEP itself is significantly modulated by irradiation in human epithelial cell lines and in breast cancer tissues from radiotherapy-treated patients. These results confirm and extend the previous evidence that LEP has a general and important role in the response of mammalian cells to irradiation.

Abstract 3973: Role of thyroid tumor microenvironment secretome in cancer initiation and progression

Abstract The incidence of thyroid cancer in the United States is on a rise with an appreciably high disease recurrence rate of 20-30%. Tumor associated macrophages (TAMs) release cytokines, chemokines and other secretory components like exosomes which aid in thyroid tumor progression and metastasis. In our previous study on thyroid tumor microenvironment, we established that M1 polarized pro-inflammatory macrophages modulate thyroid cancer phenotype. TAMs secretome, consisting of pro-inflammatory cytokines such as TGF-β, IL6, TNF-α, IL-1β, amongst others, induce epithelial to mesechymal transition (EMT) in thyroid cancer cells promoting tumor metastasis and propagation. In our present study, we used an in vitro model system to assess the effects of secretory molecules called exosomes, in the thyroid tumor microenvironment. We used thyroid cancer cell lines: BCPAP (papillary), 8505C (anaplastic) and CGTHW-1 (follicular) to represent the spectrum of clinically observed thyroid cancers. THP-1 monocyte/macrophage cell line was used to denote the inflammatory component. Thyroid cancer cells treated with activated M1 polarized THP-1 macrophage exosomes showed halt in proliferation, transformation to mesenchymal phenotype as well as modulation in expression of EMT markers, such as vimentin and NFk-B, indicative of induction of EMT in thyroid cancer cells. Interestingly, secretory exosomes from anaplastic thyroid cancer cells led to activation of THP-1 monocytes. Since the exosomal cargo is the reflection and fingerprint of its originating parental cells, we profiled exosomal miRNA derived from thyroid cancer cells and THP1 cells. Modulation of various miRNA in follicular and anaplastic thyroid cancer exosomes was observed, when compared to papillary thyroid cancer exosomes. We detected a down regulation of miR-138-5p, miR-146a-5p, miR-26a-5p, miR-26b-5p, miR-34a-5p and miR-31-5p in anaplastic and follicular cancer exosomes, which may play a role in promoting cancer invasion and metastasis. In comparison to papillary thyroid cancer exosomes, an upregulation of miR-214-3p, miR-200a-3p, miR-298, miR-299-3p, and miR-302a-3p was ascertained in follicular thyroid cancer exosomes. Conversely, we noted a down regulation of these miRNAs in anaplastic thyroid cancer exosomes. These distinct miRNA expressions in cancer secretome will provide new insights into the tumor development and dissemination. Our findings suggest an important crosstalk between the secretome of thyroid cancer cells and inflammatory cells in tumor microenvironment, defining thyroid cancer phenotype. These exosomal miRNA serve as early diagnostic markers of thyroid cancer differentiation as well as targets for novel therapies specifically for anaplastic thyroid cancer. Citation Format: Neha Yashpal Tuli, Ameet Kamat, Rachana Maniyar, Ghada Ben Rahoma, Sanjukta Chakraborty, Sarnath Singh, Augustine Moscatello, Jan Geliebter, Raj K. Tiwari. Role of thyroid tumor microenvironment secretome in cancer initiation and progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3973. doi:10.1158/1538-7445.AM2017-3973

Specific Depletion of Leukemic Stem Cells: Can MicroRNAs Make the Difference?

For over 40 years the standard treatment for acute myeloid leukemia (AML) patients has been a combination of chemotherapy consisting of cytarabine and an anthracycline such as daunorubicin. This standard treatment results in complete remission (CR) in the majority of AML patients. However, despite these high CR rates, only 30–40% (<60 years) and 10–20% (>60 years) of patients survive five years after diagnosis. The main cause of this treatment failure is insufficient eradication of a subpopulation of chemotherapy resistant leukemic cells with stem cell-like properties, often referred to as “leukemic stem cells” (LSCs). LSCs co-exist in the bone marrow of the AML patient with residual healthy hematopoietic stem cells (HSCs), which are needed to reconstitute the blood after therapy. To prevent relapse, development of additional therapies targeting LSCs, while sparing HSCs, is essential. As LSCs are rare, heterogeneous and dynamic, these cells are extremely difficult to target by single gene therapies. Modulation of miRNAs and consequently the regulation of hundreds of their targets may be the key to successful elimination of resistant LSCs, either by inducing apoptosis or by sensitizing them for chemotherapy. To address the need for specific targeting of LSCs, miRNA expression patterns in highly enriched HSCs, LSCs, and leukemic progenitors, all derived from the same patients’ bone marrow, were determined and differentially expressed miRNAs between LSCs and HSCs and between LSCs and leukemic progenitors were identified. Several of these miRNAs are specifically expressed in LSCs and/or HSCs and associated with AML prognosis and treatment outcome. In this review, we will focus on the expression and function of miRNAs expressed in normal and leukemic stem cells that are residing within the AML bone marrow. Moreover, we will review their possible prospective as specific targets for anti-LSC therapy.

MicroRNA in glutamate receptor-dependent neurological diseases.

Glutamate-mediated excitotoxicity is the major neuropathological process contributing to numerousneurological diseases. Recently, emerging evidence indicates thatmicroRNAs (miRNAs) play essential roles in the pathophysiology of a wide range of neurological diseases. Notably, there have been significant developments in understanding the biogenesis of miRNAs, their regulatory mechanisms, and their potential as effective biomarkers and therapies. In the present review, we summarize the recent literature that highlights the versatileroles played by miRNAs in glutamate receptor (GluR)-dependent neurological diseases. Based on the reported studies to date, modulation of miRNAs could emerge as a promising therapeutic target for a variety of neurological diseases that were discussed in this review.

OP-15 - Tocotrienols induce the expression of specific miRNA in breast cancer cells

We have demonstrated that γ-and δ-tocotrienol (γ-and δ-T3) induce apoptosis in human breast cancer cells (MDA-MB-231 and MCF-7) at least in part, by the binding and activation of the estrogen receptor-β (ERβ). Further experiments conducted in HeLa cells, a line of human cervical cancer cells void of any canonical ER, demonstrated that γ-and δ-T3 induce Ca2+ release. This event is eventually followed by the induction of specific Ca-dependent signals leading to the expression and activation of IRE1-α and, in turn, to the alternative splicing of the pro-apoptotic protein sXBP-1 and other molecules involved in the Unfolded Protein Response, the core pathway coping with endoplasmic reticulum (EndoR) stress in eukaryotic cells. More recently, we observed that γ-T3 modulates the expression of a specific set of miRNAs in HeLa cells. The list of modulated miRNAs was intersected with the differential gene expression profile of HeLa cells treated with γ-T3 versus untreated cells. On the basis of data interrogation, we focused our attention on miR190b, which is involved in the alternative splicing of the pro-apoptotic protein XBP-1. Experiments based on miR190b silencing confirmed its role in the alternative splicing of XBP1 and in IRE-1 pathway. Our observations suggest that tocotrienols may have a potential role in the clinical management of some specific kind of cancer.

Cruciferous vegetables and colorectal cancer prevention through microRNA regulation: A review

ABSTRACTDiets rich in fruits and vegetables may lower colorectal cancer risk. In particular, a number of in vitro and in vivo studies demonstrated that cruciferous vegetables and their active compounds elicit chemopreventive potency through multiple mechanisms. However, it is relatively unexplored whether these vegetables modulate the risk of cancer development through epigenetic mechanisms including noncoding RNAs. Therefore, the objective of the present review is to report and discuss existing evidence with regards to modulation of microRNAs (miRNAs), one variety of noncoding RNAs, by cruciferous vegetables and their chemo-preventive effects against colorectal cancers. As results, it seems clear, considering accumulating evidence regarding their interactions with cancer related genes and relevant signaling pathways, that miRNA modulation via cruciferous vegetables is an attractive target for the prevention of colorectal cancer. In addition, miRNAs have been characterized as diagnostic and prognostic biomarkers and utilized in cancer therapeutics. Thus, it is very possible that natural agents (not limited to those in cruciferous vegetables) enhance cancer therapeutic efficacy and elicit chemopreventive effects through modulating key miRNAs.