Predicting miRNA Targets by Integrating Gene Regulatory Knowledge with Expression Profiles

Altered Circulating MicroRNA Profiles After Endurance Training: A Cohort Study of Ultramarathon Runners

BACKGROUND

Despite the positive effects of endurance training on the cardiovascular (CV) system, excessive exercise induces not only physiological adaptations but also adverse changes in CV system, including the heart. We aimed to evaluate the selected miRNAs expression based on bioinformatic analysis and their changes before and after an ultramarathon run.

MATERIALS AND METHODS

Cardiac tissue-specific targets were identified with the Tissue 2.0 database. Gene-gene interaction data were retrieved from the STRING app for Cytoscape. Twenty-three endurance athletes were recruited to the study. Athletes ran to completion (100 km) or exhaustion (52-91 km, median 74 km). All participants completed pre- and post-run testing. miRNAs expressions were measured both before and after the race.

RESULTS

Enrichment analysis of the signaling pathways associated with the genes targeted by miRNAs selected for qRT-PCR validation (miR-1-3p, miR-126, miR-223, miR-125a-5p, miR-106a-5p, and miR-15a/b). All selected miRNAs showed overlap in regulation in pathways associated with cancer, IL-2 signaling, TGF-β signaling as well as BDNF signaling pathway. Analysis of metabolites revealed significant regulation of magnesium and guanosine triphosphate across analyzed miRNA targets. MiR-1-3p, miR-125a-5p, miR-126, and miR-223 expressions were measured in 23 experienced endurance athletes, before and after an ultramarathon wherein athletes ran to completion (100 km) or exhaustion (52-91 km, median 74 km). The expressions of miR-125a-5p, miR-126, and miR-223 were significantly increased after the race (p = 0.007, p = 0.001, p = 0.014, respectively). MiR-1-3p expression post-run showed a negative correlation with the post-run levels of high-sensitivity C-reactive protein (hs-CRP) (r = -0.632, p = 0.003). Higher miR-1-3p expression was found in runners, who finished the race under 10 h compared to runners who finished over 10 h (p = 0.001). Post-run miR-125a-5p expression showed a negative correlation with the peak lactate during the run (r = -0.576, p = 0.019).

CONCLUSION

Extreme physical activity, as exemplified by an ultramarathon, is associated with changes in circulating miRNAs' expression related to inflammation, fibrosis, and cardiac muscle function. In particular, the negative correlations between miR-125a-5p and lactate concentrations, and miR-1-3p and hs-CRP, support their role in specific exercise-induced adaptation. Further studies are essential to validate the long-term effect of these observations.

The Relation of the Brain-Derived Neurotrophic Factor with MicroRNAs in Neurodegenerative Diseases and Ischemic Stroke

Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family of growth factors that plays a crucial role in the development of the nervous system while supporting the survival of existing neurons and instigating neurogenesis. Altered levels of BDNF, both in the circulation and in the central nervous system (CNS), have been reported to be involved in the pathogenesis of neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), Huntington's disease (HD), multiple sclerosis (MS), and ischemic stroke. MicroRNAs (miRNAs) are a class of non-coding RNAs found in body fluids such as peripheral blood and cerebrospinal fluid. Several different miRNAs, and their target genes, are recognized to be involved in the pathophysiology of neurodegenerative and neurovascular diseases. Thus, they present as promising biomarkers and a novel treatment approach for CNS disorders. Currently, limited studies provide viable evidence of miRNA-mediated post-transcriptional regulation of BDNF. The aim of this review is to provide a comprehensive assessment of the current knowledge regarding the potential diagnostic and prognostic values of miRNAs affecting BDNF expression and its role as a CNS disorders and neurovascular disease biomarker. Moreover, a novel therapeutic approach in neurodegenerative diseases and ischemic stroke targeting miRNAs associated with BDNF will be discussed.

LINC00459 sponging miR-218 to elevate DKK3 inhibits proliferation and invasion in melanoma

The lncRNA biomarkers in melanoma remain to be further explored. The lncRNAs with different expression levels in melanoma tissue were identified by microarray analysis. To investigate the biological functions of target lncRNA, several in-vivo and in-vitro studies were performed. Potential mechanisms of competitive endogenous RNAs (ceRNAs) were predicted by using bioinformatics analysis and explored by western blot assay, fluorescence in situ hybridization assay, real-time quantitative PCR (RT-qPCR) array, RNA pull-down analysis, AGO2-RIP assay, and dual-luciferase reporter assay. The results demonstrated decreased LINC00459 in melanoma cell lines and tissues. According to the in-vitro and in-vivo experiments, up-regulated LINC00459 had inhibitory effect on cell proliferation and invasion. Bioinformatics analyses suggested that miR-218 could be a direct target of LINC00459. In addition, miR-218 was proved to be able to directly target the dickkopf-related protein 3 (DKK3) gene. In conclusion, our analysis suggested that the LINC00459 could sponge miR-218 and increase the expression of DKK3 gene, thus inhibiting the invasion and proliferation of melanoma cells, which indicated that the LINC00459 could be an effective biomarker for melanoma and its potential as the therapeutic target.

Exploring the Potential of MicroRNA Let-7c as a Therapeutic for Prostate Cancer

Prostate cancer (PCa) is one of the leading causes of mortality worldwide and often presents with aberrant microRNA (miRNA) expression. Identifying and understanding the unique expression profiles could aid in the detection and treatment of this disease. This review aims to identify miRNAs as potential therapeutic targets for PCa. Three bio-informatic searches were conducted to identify miRNAs that are reportedly implicated in the pathogenesis of PCa. Only hsa-Lethal-7 (let-7c), recognized for its role in PCa pathogenesis, was common to all three databases. Three further database searches were conducted to identify known targets of hsa-let-7c. Four targets were identified, HMGA2, c-Myc (MYC), TRAIL, and CASP3. An extensive review of the literature was undertaken to assess the role of hsa-let-7c in the progression of other malignancies and to evaluate its potential as a therapeutic target for PCa. The heterogeneous nature of cancer makes it logical to develop mechanisms by which the treatment of malignancies is tailored to an individual, harnessing specific knowledge of the underlying biology of the disease. Resetting cellular miRNA levels is an exciting prospect that will allow this ambition to be realized.

LINC00612 enhances the proliferation and invasion ability of bladder cancer cells as ceRNA by sponging miR-590 to elevate expression of PHF14

Background

Bladder cancer (BC) is a common type of cancer that involves tumors of the urinary system and poses a serious threat to human health. Long noncoding RNAs (lncRNAs) have emerged as crucial biomarkers and regulators in many cancers. Novel lncRNA biomarkers in BC urgently need to be investigated in regard to its function and regulatory mechanisms.

Methods

Identification of differentially expressed lncRNAs in BC tissue was performed via microarray analysis. To investigate the biological functions of LINC00612, loss-of-function and gain-of-function experiments were performed in vitro and in vivo. Bioinformatics analysis, dual-luciferase reporter assays, AGO2-RIP assays, RNA pull-down assays, real-time quantitative PCR (RT-qPCR) arrays, fluorescence in situ hybridization assays, and western blot assays were conducted to explore the underlying mechanisms of competitive endogenous RNAs (ceRNAs).

Results

LINC00612 was upregulated in BC tissues and cell lines. Functionally, downregulation of LINC00612 inhibited cell proliferation and invasion in vitro and in vivo, whereas overexpression of LINC00612 resulted in the opposite effects. Bioinformatics analysis and luciferase assays revealed that miR-590 was a direct target of LINC0061, which was validated by dual-luciferase reporter assays, AGO2-RIP assays, RNA pull-down assays, RT-qPCR arrays, and rescue experiments. Additionally, miR-590 was shown to directly target the PHD finger protein 14 (PHF14) gene. LNIC00612 modulated the expression of E-cadherin and vimentin by competitively sponging miR-590 to elevate the expression of PHF14, thus affecting BC cellular epithelial-mesenchymal transition (EMT).

Conclusions

Our results indicate that LINC00612 enhances the proliferation and invasion ability of BC cells by sponging miR-590 to upregulate PHF14 expression and promote BC cellular EMT, suggesting that LINC00612 may act as a potential biomarker and therapeutic target for BC.

Lnc SMAD5-AS1 as ceRNA inhibit proliferation of diffuse large B cell lymphoma via Wnt/β-catenin pathway by sponging miR-135b-5p to elevate expression of APC

Diffuse large B cell lymphoma (DLBCL) is a common and fatal hematological malignancy. Long noncoding RNAs (lncRNAs) have emerged as crucial biomarkers and regulators in many cancers. Novel lncRNA biomarker in DLBCL needs to be investigated badly, as well as its function and molecular mechanism. To further explore, microarray analysis was performed to identify the differentially expressed lncRNAs in DLBCL tissues. To investigate the biological functions of SMAD5-AS1, we performed gain- and loss-of-function experiments in vitro and in vivo. Furthermore, bioinformatics analysis, dual-luciferase reporter assays, Argonaute 2-RNA immunoprecipitation (AGO2-RIP), RNA pull-down assay, quantitative PCR arrays, western blot assay, TOPFlash/FOPFlash reporter assay, and rescue experiments were conducted to explore the underlying mechanisms of competitive endogenous RNAs (ceRNAs). We found that SMAD5-AS1 was down-regulated in DLBCL tissues and cell lines. Functionally, SMAD5-AS1 downregulation promoted cell proliferation in vitro and in vivo, whereas SMAD5-AS1 overexpression could lead to the opposite effects in vitro and in vivo. Bioinformatics analysis and luciferase assays revealed that miR-135b-5p was a direct target of SMAD5-AS1, which was validated by dual-luciferase reporter assays, AGO2-RIP, RNA pull-down assay, and rescue experiments. Also, dual-luciferase reporter assays and rescue experiments demonstrated that miR-135b-5p targeted the adenomatous polyposis coli (APC) gene directly. SMAD5-AS1/miR-135b-5p inhibits the cell proliferation via inactivating the classic Wnt/β-catenin pathway in the form of APC dependency. Our results indicated that SMAD5-AS1 inhibits DLBCL proliferation by sponging miR-135b-5p to up-regulate APC expression and inactivate classic Wnt/β-catenin pathway, suggesting that SMAD5-AS1 may act as a potential biomarker and therapeutic target for DLBCL.

Prediction of Plant miRNA Targets

microRNAs (miRNAs) are the central component of an important layer of regulation of gene expression at posttranscriptional level. In plants, miRNAs target the transcripts in a highly complementary sequence-dependent manner. Extensive research is being made to study genome-wide miRNA-mediated regulation of gene expression, which has resulted in the development of many tools for in silico prediction of miRNA targets. Although several tools have been developed for predicting miRNA targets in model plants, genome-wide analysis of miRNA targets is still a challenge for non-model species that lack dedicated tools. Here, we describe an in silico procedure for studying miRNA-mediated interactions in plants, which is based on the fact that canonical miRNA-target sites are highly complementary, the miRNAs negatively regulate the expression of their target genes, and miRNAs may form regulatory networks as one miRNA may target more than one transcript and vice versa to modulate and fine-tune expression of the genome.

Estimating heterogeneous treatment effect by balancing heterogeneity and fitness

Background

Estimating heterogeneous treatment effect is a fundamental problem in biological and medical applications. Recently, several recursive partitioning methods have been proposed to identify the subgroups that respond differently towards a treatment, and they rely on a fitness criterion to minimize the error between the estimated treatment effects and the unobservable ground truths.

Results

In this paper, we propose that a heterogeneity criterion, which maximizes the differences of treatment effects among the subgroups, also needs to be considered. Moreover, we show that better performances can be achieved when the fitness and the heterogeneous criteria are considered simultaneously. Selecting the optimal splitting points then becomes a multi-objective problem; however, a solution that achieves optimal in both aspects are often not available. To solve this problem, we propose a multi-objective splitting procedure to balance both criteria. The proposed procedure is computationally efficient and fits naturally into the existing recursive partitioning framework. Experimental results show that the proposed multi-objective approach performs consistently better than existing ones.

Conclusion

Heterogeneity should be considered with fitness in heterogeneous treatment effect estimation, and the proposed multi-objective splitting procedure achieves the best performance by balancing both criteria.

Non-coding RNAs: long non-coding RNAs and microRNAs in endocrine-related cancers

The human genome is 'pervasively transcribed' leading to a complex array of non-coding RNAs (ncRNAs) that far outnumber coding mRNAs. ncRNAs have regulatory roles in transcription and post-transcriptional processes as well numerous cellular functions that remain to be fully described. Best characterized of the 'expanding universe' of ncRNAs are the ~22 nucleotide microRNAs (miRNAs) that base-pair to target mRNA's 3' untranslated region within the RNA-induced silencing complex (RISC) and block translation and may stimulate mRNA transcript degradation. Long non-coding RNAs (lncRNAs) are classified as >200 nucleotides in length, but range up to several kb and are heterogeneous in genomic origin and function. lncRNAs fold into structures that interact with DNA, RNA and proteins to regulate chromatin dynamics, protein complex assembly, transcription, telomere biology and splicing. Some lncRNAs act as sponges for miRNAs and decoys for proteins. Nuclear-encoded lncRNAs can be taken up by mitochondria and lncRNAs are transcribed from mtDNA. Both miRNAs and lncRNAs are dysregulated in endocrine cancers. This review provides an overview on the current understanding of the regulation and function of selected lncRNAs and miRNAs, and their interaction, in endocrine-related cancers: breast, prostate, endometrial and thyroid.

Mining heterogeneous causal effects for personalized cancer treatment

Motivation

Cancer is not a single disease and involves different subtypes characterized by different sets of molecules. Patients with different subtypes of cancer often react heterogeneously towards the same treatment. Currently, clinical diagnoses rather than molecular profiles are used to determine the most suitable treatment. A molecular level approach will allow a more precise and informed way for making treatment decisions, leading to a better survival chance and less suffering of patients. Although many computational methods have been proposed to identify cancer subtypes at molecular level, to the best of our knowledge none of them are designed to discover subtypes with heterogeneous treatment responses.

Results

In this article we propose the Survival Causal Tree (SCT) method. SCT is designed to discover patient subgroups with heterogeneous treatment effects from censored observational data. Results on TCGA breast invasive carcinoma and glioma datasets have shown that for each subtype identified by SCT, the patients treated with radiotherapy exhibit significantly different relapse free survival pattern when compared to patients without the treatment. With the capability to identify cancer subtypes with heterogeneous treatment responses, SCT is useful in helping to choose the most suitable treatment for individual patients.

Availability and Implementation

Data and code are available at https://github.com/WeijiaZhang24/SurvivalCausalTree .

Contact

weijia.zhang@mymail.uinsa.edu.au.

Supplementary information

Supplementary data are available at Bioinformatics online.

miR-346 promotes migration and invasion of nasopharyngeal carcinoma cells via targeting BRMS1

The aim of this study is to determine the expression and roles of miR-346 in nasopharyngeal carcinoma (NPC). We showed that miR-346 was upregulated in NPC tissues compared with adjacent non-tumorous nasopharyngeal tissues. Inhibition of miR-346 significantly attenuated the migration and invasion of NPC cells. Luciferase reporter assay showed that miR-346 targeted the 3'-untranslated region (3'-UTR) of breast cancer metastasis suppressor 1 (BRMS1). Overexpression of miR-346 suppressed the endogenous expression of BRMS1 in NPC cells. There was a significant negative correlation between miR-346 and BRMS1 protein expression in NPC tissues (r = -0.372, P = 0.008). Rescue experiments demonstrated that overexpression of BRMS1 lacking the 3'-UTR impaired the invasiveness of NPC cells transfected with miR-346 mimic. Taken together, miR-346 shows the ability to promote the migration and invasion of nasopharyngeal cancer cells via targeting BRMS1 and represents a potential therapeutic target for NPC.