ABSTRACT
Alzheimer's disease (AD) is the most common type and accounts for 60%-70% of the reported cases of dementia. MicroRNAs (miRNAs) are small non-coding RNAs that play a crucial role in gene expression regulation. Although the diagnosis of AD is primarily clinical, several miRNAs have been associated with AD and considered as potential markers for diagnosis and progression of AD. We sought to match AD-related miRNAs in cerebrospinal fluid (CSF) found in the GeoDataSets, evaluated by machine learning, with miRNAs listed in a systematic review, and a pathway analysis. Using machine learning approaches, we identified most differentially expressed miRNAs in Gene Expression Omnibus (GEO), which were validated by the systematic review, using the acronym PECO-Population (P): Patients with AD, Exposure (E): expression of miRNAs, Comparison (C): Healthy individuals, and Objective (O): miRNAs differentially expressed in CSF. Additionally, pathway enrichment analysis was performed to identify the main pathways involving at least four miRNAs selected. Four miRNAs were identified for differentiating between patients with and without AD in machine learning combined to systematic review, and followed the pathways analysis: miRNA-30a-3p, miRNA-193a-5p, miRNA-143-3p, miRNA-145-5p. The pathways epidermal growth factor, MAPK, TGF-beta and ATM-dependent DNA damage response, were regulated by these miRNAs, but only the MAPK pathway presented higher relevance after a randomic pathway analysis. These findings have the potential to assist in the development of diagnostic tests for AD using miRNAs as biomarkers, as well as provide understanding of the relationship between different pathophysiological mechanisms of AD.
ABSTRACT
BACKGROUND: Cardiotoxicity is a common and serious adverse effect of anthracycline therapy in breast cancer patients. The current criteria for cardiotoxicity are based on imaging and cardiac biomarkers. However, there is a need for new biomarkers to help with early diagnosis. MicroRNAs (miRNAs) are small non-coding RNA molecules that play an important role in the regulation of gene expression. Several miRNAs have been associated with cardiovascular diseases and are biomarkers under investigation for cancer treatment-related cardiotoxicity. METHODS: We performed a systematic literature search of Medline/PubMed, Cochrane Central Register of Controlled Trials, Scopus, Lilacs, Web of Science and Embase, until April 2020. Cohort studies that reported miRNA biomarkers in breast cancer patients with anthracycline-induced cardiotoxicity and non-cardiotoxicity patients were included. Moreover, we searched the miRTarBase for experimentally validated miRNA-target interactions. RESULTS: Among the 209 studies retrieved, five fulfilled the inclusion criteria. Let-7f, miR-1, miR-20a, miR-126 and miR-210 were validated in two population-based cohorts. The pro-angiogenic miRNAs let-7f, miR-20a, miR-126 and miR-210 were significantly down-regulated in epirubicin-cardiotoxicity when compared to the non-cardiotoxicity group. miR-1 has been shown to provide diagnostic and prognostic information in the setting of myocardial infarction, but changes in its levels are controversial in doxorubicin-treated breast cancer patients with cardiotoxicity. Reactome pathways relevant to cardiotoxicity were found from the target genes for let-7f, miR-1, miR-20a, miR-126 and miR-210 at miRTarBase. CONCLUSION: The data suggest that let-7f, miR-1, miR-20a, miR-126 and miR-210 are associated with anthracycline-based cardiotoxicity during chemotherapy in breast cancer patients.
