miRNAs and their role in the correlation between schizophrenia and cancer (Review)

An In Vitro Study for the Role of Schizophrenia-Related Potential miRNAs in the Regulation of COMT Gene

This study aimed to analyze the possible association of miR-30a-5p, miR-30e-5p, and miR-34a-5p identified as potential candidate miRNAs in schizophrenia, with the COMT gene. Candidate miRNAs were obtained from the TargetScan database. The SH-SY5Y human neuroblastoma cell line was used as a cellular model for schizophrenia. miR-30a-5p, miR-30e-5p, and miR-34a-5p mimics were transfected into the SH-SY5Y cell line. Total RNA was isolated from transfected cells and RNA-IP samples and reverse transcripted for miRNA and mRNA analysis. RT-qPCR and western blot were performed to observe changes in expression levels of COMT. RNA-ımmunoprecipitation was performed to determine RNA-protein interactions after mimic transfection. In the study, it was observed that COMT gene expression levels decreased significantly after miR-30a-5p and miR-34a-5p expressions, whereas increased significantly as a result of miR-30e-5p transfection. RNA-IP data have shown that the amount of COMT pulled down by Ago2 was increased after miR-30a-5p and miR-34a-5p transfections. RNA-IP results revealed that miR-30a-5p and miR-34a-5p are direct targets for the COMT gene.

Downregulation of microRNA-330-5p induces manic-like behaviors in REM sleep-deprived rats by enhancing tyrosine hydroxylase expression

AIM

In our pilot study, we found an increase in tyrosine hydroxylase (Th) mRNA expression in the prefrontal cortex of 72-h REM sleep-deprived (SD) rats, a mania model. Additionally, the expression levels of miR-325-3p, miR-326-3p, and miR-330-5p, the predicted target miRNAs on TH, were significantly decreased. Based on these results, in this study, we investigated whether miRNA-325-3p, miR-326-3p, and miR-330-5p modulate TH and manic-like behaviors in SD rats.

METHODS

Manic-like behaviors were assessed using the open field test (OFT) and elevated plus-maze (EPM) test. The direct binding activity of miRNAs to the 3'-untranslated region (3'-UTR) of the Th gene was measured in HEK-293 cells using a luciferase reporter system. We also examined mRNA and protein expression of TH after intracerebroventricular (ICV) injection of miR-330-5p agomir to SD rats, along with manic-like behaviors.

RESULTS

We observed an upregulation in mRNA and protein expression of TH and downregulation in miRNA-325-3p, miR-326-3p, and miR-330-5p expressions in the prefrontal cortex of SD rats, together with increased manic-like behaviors. The luciferase reporter assay showed that miR-330-5p could repress TH expression through direct binding to its target site in the 3'-UTR of Th, whereas miR-326-3p and miR-330-5p could not. In addition, ICV injection of miR-330-5p agomir alleviated the increase in TH expression in the prefrontal cortex of SD rats and manic-like behaviors.

CONCLUSIONS

TH expression regulation through miR-330-5p may be implicated in the pathophysiology of mania in SD rats.

MicroRNA schizophrenia: Etiology, biomarkers and therapeutic targets

The three sets of symptoms associated with schizophrenia-positive, negative, and cognitive-are burdensome and have serious effects on public health, which affects up to 1% of the population. It is now commonly believed that in addition to the traditional dopaminergic mesolimbic pathway, the etiology of schizophrenia also includes neuronal networks, such as glutamate, GABA, serotonin, BDNF, oxidative stress, inflammation and the immune system. Small noncoding RNA molecules called microRNAs (miRNAs) have come to light as possible participants in the pathophysiology of schizophrenia in recent years by having an impact on these systems. These small RNAs regulate the stability and translation of hundreds of target transcripts, which has an impact on the entire gene network. There may be improved approaches to treat and diagnose schizophrenia if it is understood how these changes in miRNAs alter the critical related signaling pathways that drive the development and progression of the illness.

A longitudinal study of alterations of circulating DJ-1 and miR203a-3p in association to olanzapine medication in a sample of first episode patients with schizophrenia

Among different proposed pathophysiological mechanisms, redox imbalance has been suggested to be a potential contributor in the pathogenesis of schizophrenia. DJ-1 is a redox-sensitive protein that has been shown to have neuroprotective function in the brain in Parkinson's disease and other neurodegenerative diseases. However, a role for DJ-1 in schizophrenia is unknown. Bioinformatic analysis suggested that microRNA (miR)-203a-3p could target the 3' untranslated region (UTR) of DJ-1. In whole blood and blood-derived exosomes of 11 first episode antipsychotic naïve schizophrenia patients, DJ-1 protein and mRNA demonstrated decreased DJ-1 mRNA and protein and increased miR203a-3p levels compared to healthy controls. In whole blood, antipsychotic monotherapy with olanzapine for 6 weeks increased DJ-1 and attenuated miR203a-3p levels, whereas in blood derived exosomes, olanzapine returned DJ-1 and miR203a-3p to levels seen healthy controls. Consistent with this finding, we showed that human umbilical vein endothelial cells (HUVACs) transfected with a DJ-1-3' UTR luciferase reporter construct displayed reduced gene expression when subjected to the oxidative stressor H₂O_2. Transfection of a miR203a-3p mimic into HUVACs reduced DJ-1-3 'UTR reporter gene expression, while transfection of an anti miR-203a-3p prevented the H₂O₂-induced downregulation of the reporter gene. We conclude that miR-203a-3p is an essential mediator of oxidative stress in schizophrenia via its ability to target the 3' UTR of DJ-1 and antipsychotic monotherapy restores DJ-1 antioxidant levels by regulating miR203a-3p expression. miR-203a-3p and DJ-1 might represent attractive targets for the treatment of pathologies such as schizophrenia that has underlying oxidative stress.

Functional Variants of miR-143 Are Associated with Schizophrenia Susceptibility: A Preliminary Population-Based Study and Bioinformatics Analysis

Single nucleotide polymorphisms within genes encoding microRNAs may alter the expression of microRNAs and their target genes, contributing to the etiology of psychiatric disorders. We aimed to investigate the link between rs4705342T/C and rs4705343T/C polymorphisms in the promoter region of miR-143 and the risk of schizophrenia (SCZ) in a sample of an Iranian population. In this experimental study, a total of 398 subjects were recruited. Genotyping carried out using allele-specific PCR (AS-PCR) method. Different bioinformatics databases and Cytoscape V3.4.0 software were used for the analysis of the gene-miRNA interaction network. The genotypic analysis of rs4705342C/T showed that CC genotype in the co-dominant model significantly decreased the risk of SCZ (p < 0.001). Also, a significantly reduced risk of SCZ was observed under allelic (p < 0.001), dominant (p = 0.007), and recessive (p = 0.001) models of this variant. As regards rs4705343T/C, significantly enhanced risk of SCZ was found under the co-dominant CC (p = 0.01) and recessive (p = 0.007) contrasted genetic models. For this variant, the C allele conferred an increased risk of SCZ by 1.41 fold. Haplotype analysis showed that the C_rs4705342 T_rs4705343 haplotype significantly diminished SCZ susceptibility. The result of the bioinformatics analysis showed that miR-143, as a critical miRNA, targets ERK5, ERBB3, HK2, and PKCε, the four major genes involved in SCZ development. Our findings suggest that these two polymorphisms might affect SCZ susceptibility. Elucidating the precise regulatory mechanisms of gene expression in the development of SCZ will help researchers discover a novel target for therapeutic interventions.

Double-Edged Sword of Tumour Suppressor Genes in Schizophrenia

Schizophrenia (SCZ) is a common psychiatric disorder with polygenetic pathogenesis. Among the many identified candidate genes and loci, the group of tumour suppressor genes has drawn our interest. In this mini-review article, we describe evidence of a correlation between major tumour suppressor genes and SCZ development. Genetic mutations ranging from single nucleotide polymorphisms to large structural alterations have been found in tumour-related genes in patients with SCZ. Epigenetic mechanisms, including DNA methylation/acetylation and microRNA regulation of tumour suppressor genes, have also been implicated in SCZ. Beyond genetic correlations, we hope to establish causal relationships between tumour suppressor gene function and SCZ risk. Accumulating evidence shows that tumour suppressor genes may mediate cell survival and neural development, both of which contribute to SCZ aetiology. Moreover, converging intracellular signalling pathways indicate a role of tumour suppressor genes in SCZ pathogenesis. Tumour suppressor gene function may mediate a direct link between neural development and function and psychiatric disorders, including SCZ. A deeper understanding of how neural cell development is affected by tumour suppressors may lead to improved anti-psychotic drugs.

Deciphering the paradoxical incidence of cancer in schizophrenia

OBJECTIVES:

The incidence of cancer in schizophrenia has been an area of controversy. The current article aims to provide a commentary outlining the contradictory findings of incidence of cancer in schizophrenia as well as discuss the available theories linking cancer with schizophrenia and address the methodological issues of the studies which could lead to the discrepant findings.

METHOD:

A literature search was carried out primarily using the electronic database of MEDLINE through PubMed using the search terms 'cancer' and 'schizophrenia'. Google Scholar was used to supplement the search.

RESULTS:

The findings were inconclusive, with studies documenting increased, decreased as well as no risk of cancer in patients with schizophrenia, compared with the general population. Several methodological limitations exist with regard to measures of assessment, sample size and selection bias.

CONCLUSIONS:

The association between cancer and schizophrenia remains controversial. Genetic as well as environmental theories exist explaining the paradoxical incidence of cancer in schizophrenia. The methodological factors could contribute to the discrepant findings.

Lower risk of liver cancer in patients with schizophrenia: a systematic review and meta-analysis of cohort studies

Previous studies regarding the association between schizophrenia and the subsequent risk of liver cancer have shown inconsistent results. We aimed to perform a systematic review and meta-analysis to evaluate the association between schizophrenia and liver cancer incidence. We systematically searched the PubMed and Embase electronic databases for cohort studies reporting the standardized incidence ratio (SIR) for the risk of liver cancer in patents with schizophrenia as compared with the general population. A random-effects model was used to analyze the data. Stratified analyses were performed according to the gender of the patients. Seven studies comprising 312,834 patients with schizophrenia were included. During follow-up, 581 liver cancer cases were confirmed. The meta-analysis results showed that schizophrenia was associated with a trend of a lower liver cancer incidence (SIR: 0.83, 95% confidence interval [CI]: 0.66–1.04, p = 0.10) with significant heterogeneity (I² = 81%). Sensitivity analysis of five cohorts of patients with cancer events before the diagnosis of schizophrenia indicated that schizophrenia was associated with a significantly lower incidence of liver cancer (SIR: 0.76, 95% CI: 0.61–0.96, p = 0.02; I² = 84%). The reduction of a subsequent incidence of liver cancer was significant in male patients with schizophrenia (SIR: 0.71, p = 0.005), and a trend of a reduced risk of liver cancer was also detected in female patients (SIR: 0.83, p = 0.12). Significant publication bias was detected. However, “trim and fill” analyses by including the imputed unpublished studies showed similar results. In summary, schizophrenia may be protective against the incidence of liver cancer.

The effects of microRNA-183 promots cell proliferation and invasion by targeting MMP-9 in endometrial cancer

MiRNAs are known to play important roles in cancer cell development. However, the pattern and biological role of miR-183 in endometrial cancer (EC) have not been completely unexplored. Here, we found that miR-183 was upregulated in endometrial cancer cells. The purpose of the study was to evaluate the function of miR-183 in the endometrial cancer cell line and the mechanisms regulating its direct target protein in these processes. The mRNA and protein expressions were analyzed by quantitative RT-PCR and western blotting, respectively. The experiments about MTT assay, colony formation assay and transwell assay showed that miR-183 can positively regulate cell proliferation, migration and invasion in vitro. Furthermore, the in vivo experiments indicated that knockdown of miR-183 significantly attenuated EC cells growth. Mechanistically, luciferase reporter assay and western blotting assay was conducted to confirm target associations. The data analysis revealed that MMP-9 as a direct target of miR-183 in EC and there was a negatively relationship between miR-183 and MMP-9 expression in EC cells. Taken together, our results demonstrated that miR-183 plays a critical role in EC tumorigenesis and metastasis by suppressing MMP-9 expression, which may be an attractive therapeutic target for the treatment of endometrial cancer.