The potential of miRNAs for diagnosis,treatment and monitoring of breast cancer

Abstract

Dysregulation of microRNAs (miRNAs) has a fundamental role in the initiation, development and progression of several human cancers, including breast cancer (BC), since strong evidence has shown that miRNAs can regulate the expression of oncogenes or tumor suppressor genes. A possible role of miRNAs in the diagnosis in BC has been demonstrated. As miRNAs has been found stable in biofluids, extracellular multiple miRNA profiles have been proposed as diagnostic tools, showing better diagnostic performance than individual miRNAs in BC. In this paper, based on the current literature, we present the role of microRNAs in the diagnosis and therapy monitoring of BC. Furthermore, we report new miRNA-based drugs that could be turned into promising therapy for BC, alone or in combination with conventional therapy. We also discuss how extracellular miRNAs could become new, easily accessible, affordable, non-invasive tools for BC patients.     

The miR-124 regulates the expression of BACE1/β-secretase correlated with cell death in Alzheimer's disease

The role of miR-124 on the expression of β-site APP cleaving enzyme 1 (BACE1), an important cleavager of amyloid precursor protein that plays a pivotal role in the β-amyloid production, was studied in this paper using cellular models for Alzheimer’ disease (AD) of cultured PC12 cell lines and primary cultured hippocampal neurons. The aim of the present study was to uncover novel potential miR-124 targets and shed light on its function in the cellular AD model. MiR-124 expression was steadily altered when its mimic and inhibitor were transfected in vitro. The results showed the expression of BACE1, one of the potential functional downstream targets of miR-124, was well correlated with cell death induced by Aβ neurotoxicity, and its expression level could be up- and down-regulated by suppression or over expression of miR-124 level respectively. These findings suggest that miR-124 may work as a basilic regulating factor to alleviate cell death in the process of AD by targeting BACE1, play an essential role in the control of BACE1 gene expression, and might be considered as a novel therapeutic target in treating AD.     

Review: Bio-compartmentalization of microRNAs in exosomes during gestational diabetes mellitus

Analysis of the human genome revealed that only 1.2% encoded for proteins, which raised questions regarding the biological significance of the remaining genome. We now know that approximately 80% of the genome serves at least one biochemical function within the cell. A portion of this 80% consists of a family of non-coding regulatory RNAs, one important member being microRNAs (miRNAs). miRNAs can be detected in tissues and biofluids, where miRNAs in the latter can be bound to proteins or encapsulated within lipid vesicles such as exosomes. Gestational diabetes mellitus (GDM) is a complication of pregnancy, which has harmful health impacts on both the fetus as well as the mother. The incidence of GDM worldwide varies, but reached 18% in the HAPO cohort using the new International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria. Not only has GDM been associated with increased risks of further complications during pregnancy, but also poses long-term risks for both the mother and the baby. Thus, understanding the pathophysiology of GDM is important from a public health perspective. Literature has demonstrated that GDM is associated with elevated levels of circulating exosomes in maternal circulation. However, there is a paucity of data defining the expression, role, and diagnostic utility of miRNAs in GDM. This review briefly summarizes recent advances in the function and quantification of intracellular and extracellular miRNAs in GDM.     

DCP1 forms asymmetric trimers to assemble into active mRNA decapping complexes in metazoa

DCP1 stimulates the decapping enzyme DCP2, which removes the mRNA 5′ cap structure committing mRNAs to degradation. In multicellular eukaryotes, DCP1-DCP2 interaction is stabilized by additional proteins, including EDC4. However, most information on DCP2 activation stems from studies in S. cerevisiae, which lacks EDC4. Furthermore, DCP1 orthologs from multicellular eukaryotes have a C-terminal extension, absent in fungi. Here, we show that in metazoa, a conserved DCP1 C-terminal domain drives DCP1 trimerization. Crystal structures of the DCP1-trimerization domain reveal an antiparallel assembly comprised of three kinked α-helices. Trimerization is required for DCP1 to be incorporated into active decapping complexes and for efficient mRNA decapping in vivo. Our results reveal an unexpected connectivity and complexity of the mRNA decapping network in multicellular eukaryotes, which likely enhances opportunities for regulating mRNA degradation.     

Diagnostic Value of Plasma miR-145 and miR-185 as Targeting of the APRIL Oncogene in the B-cell Chronic Lymphocytic Leukemia

Background: Chronic lymphocytic leukemia (CLL) is one of the most common hematologic malignancy in adults worldwide. This cancer has a poor prognosis at different stages. So, the identification of new biomarkers is important for diagnosis of B-CLL. Considering the oncogenic role of APRIL molecule in this leukemia as well as the regulatory role of miRNAs in different signaling pathways, the present study evaluated the miRNAs targeting APRIL gene in B-CLL. Methods: The miRNAs were predicted and selected using bioinformatics algorithms. A total of 80 plasma samples were subjected to RNA extraction and synthesis of cDNA. The expressions levels of predicted miRNAs and APRIL gene in plasma of B-CLL patients and healthy individuals were assessed by Real time PCR analysis. ROC analysis was performed to investigate the role predicted miRNAs as novel biomarkers in diagnosis of B-CLL. Results: The results of the prediction showed that miR-145-5p and miR-185-5p target the APRIL gene. The expression level of APRIL gene was strikingly higher in plasma of B-CLL patients than in the healthy individuals (102, P= 0.001). On the other hand, expression levels of miR-145-5p and miR-185-5p were strikingly lower in B-CLL patients than in the healthy individuals (0.07, P= 0.001) (0.29, P= 0.001). Also, ROC curve analyses demonstrated that miR-145-5p and miR-185-5p are specific and sensitive and may serve as new biomarkers for the detection of B-CLL. (AUC; 0.95, sensitivity; %90) (AUC; 0.87, sensitivity; %63). Conclusion: These data suggest that miR-145-5p and miR-185-5p target the APRIL gene and might have a role in diagnosis of B-CLL. Therefore, these two miRNAs can be served as a novel and potential biomarker for detection of B-CLL.     

Pap Smear miR-92a-5p and miR-155-5p as potential diagnostic biomarkers of squamous intraepithelial cervical cancer

Background: one of the female-specific diseases with a high incidence and mortality is cervical cancer. The main cause of cervical cancer is infection with Human papilloma virus (HPV). Low-grade squamous intraepithelial lesions (LSIL) and High-grade squamous intraepithelial lesions (HSIL) usually is caused by an HPV infection. Considering the role of microRNAs (miRNAs) as diagnostic biomarkers for a variety of cancers, the aim of this study was to determine miR-92a-5p and miR-155-5p expression levels in LSIL and HSIL Pap Smear samples. Methods: After initial bioinformatic studies, A total of 75 samples (25 samples of patients with LSIL, 25 patients with HSIL and 25 healthy individuals) were subjected to RNA extraction and cDNA synthesis. The expressions levels of confirmed miRNAs in samples of patients with LSIL, HSIL and healthy individuals were evaluated by Real time PCR analysis. To demonstration the role of predicted miRNAs as novel biomarkers in diagnosis of LSIL and HSIL, ROC curve analysis was done. Results: Bioinformatics results showed that miR-92a-5p and miR-155-5p target the HPV E6 and E7 genes. The expression levels of these miRNAs were strikingly higher in Pap smear of patients with LSIL than in the healthy individuals (35.36, P = 0.001) (62.23, P = 0.001). Similarity, expression levels of miR-92a-5p and miR-155-5p were amazingly higher in patients with HSIL than in the healthy individuals (33.62, P= 0.001) (69.07, P= 0.001). Although, the levels of miR-92a-5p (0.95, P = 0. 85) and miR-155-5p (1.11, P = 0.84) exhibited no statistical differences between patients with LSIL and HSIL. Also, ROC curve analyses verified that miR-92a-5p and miR-155-5p are specific and sensitive and may serve as new biomarkers for the early detection of cervical cancer. Conclusion: These data suggest miR-92a-5p and miR-155-5p, which are upregulated in LSIL and HSIL, can be consider as predictive biomarkers for the prognosis of cervical cancer patients.