The role of upregulated miR-375 expression in breast cancer: An in vitro and in silico study.

Breast cancer (BC) is the most common cancer worldwide. However, the expression and potential mechanism of miR-375 in BC are still controversial. We first collected microRNA chips and microRNA sequencing data from multiple databases for analyzing the expression level of miR-375, and further exploring the target genes and underlying molecular mechanism in BC. miR-375 in BC was predominantly overexpressed compared with that in normal breast tissues (pooled standard mean difference [SMD] = 0.49; 95 % confidence interval [CI]: 0.24-0.73, p < 0.0001). Meanwhile, the overall pooled area under the curve (AUC) in the summary receiver operating characteristic (SROC) of miR-375 was 0.83 (95 % CI = 0.79-0.86) based on 2928 cases of BC patients and 816 cases of controls, while the diagnostic positive likelihood ratio (DLR) positive and the DLR negative value were 3.90 (95 % CI = 2.46-6.19) and 0.39 (95 % CI = 0.28-0.54), respectively. The hazard ratios (HRs) were 1.29 (95 % CI = 1.04-1.6, P = 0.02) and 1.23 (95 % CI = 0.89-1.7, P = 0.22) for the cohorts of METABRIC and The Cancer Genome Atlas (TCGA). In vitro study demonstrated that miR-375 inhibitor could suppress the cell growth and induce apoptosis of BC cells. A total of 107 overlapping genes from microarrays after miR-375 transfection, the TCGA RNA sequencing, the microarrays of Affymetrix platform, and online predicting software were selected as the prospective targets of miR-375 in BC. Based on Gene Ontology (GO) enrichment analysis, the potential targets of miR-375 were notable for their somatic stem cell division, plasma membrane, and proline-rich region binding. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway examination demonstrated that the targets were associated with the pathways of prion diseases, proteoglycans in cancer, and focal adhesion. Then, 107 targets of miR-375 in BC were used to construct a protein-protein interaction (PPI) network. Finally, EGFR, PRKCA, PPARA, ADIPOQ, and ITSN1 were found to be the hub genes of miR-375. These targets showed negative correlations with miR-375 level. The upregulated miR-375 might play an essential part in the tumorigenesis and progression of BC.

p53 and its isoforms in DNA double-stranded break repair.

DNA double-stranded break (DSB) is one of the most catastrophic damages of genotoxic insult. Inappropriate repair of DNA DSBs results in the loss of genetic information, mutation, and the generation of harmful genomic rearrangements, which predisposes an organism to immunodeficiency, neurological damage, and cancer. The tumor repressor p53 plays a key role in DNA damage response, and has been found to be mutated in 50% of human cancer. p53, p63, and p73 are three members of the p53 gene family. Recent discoveries have shown that human p53 gene encodes at least 12 isoforms. Different p53 members and isoforms play various roles in orchestrating DNA damage response to maintain genomic integrity. This review briefly explores the functions of p53 and its isoforms in DNA DSB repair.

Oncogenic value of microRNA-15b-5p in hepatocellular carcinoma and a bioinformatics investigation.

miR-15b-5p has frequently been reported to function as a biomarker in some malignancies; however, the function of miR-15b-5p in hepatocellular carcinoma (HCC) and its molecular mechanism are still not well understood. The present study was designed to confirm the clinical value of miR-15b-5p and further explore its underlying molecular mechanism. A comprehensive investigation of the clinical value of miR-15b-5p in HCC was investigated by data mining The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets as well as literature. In addition, intersected target genes of miR-15b-5p were predicted using the miRWalk database and differentially expressed genes of HCC from TCGA. Furthermore, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were carried out. Then, a protein-protein interaction network (PPI) was constructed to reveal the interactions between some hub target genes of miR-15b-5p. The miR-15b-5p expression level in HCC was predominantly overexpressed compared with non-HCC tissues samples (SMD=0.618, 95% CI: 0.207, 1.029; P<0.0001) based on 991 HCC and 456 adjacent non-HCC tissue samples. The pooled summary receiver operator characteristic (SROC) of miR-15b-5p was 0.81 (Q*=0.74), and the pooled sensitivity and specificity of miR-15b-5p in HCC were 72% (95% CI: 69-75%) and 68% (95% CI: 65-72%), respectively. Bioinformatically, 225 overlapping genes were selected as prospective target genes of miR-15b-5p in HCC, and profoundly enriched GO terms and KEGG pathway investigation in silico demonstrated that the target genes were associated with prostate cancer, proximal tubule bicarbonate reclamation, heart trabecula formation, extracellular space, and interleukin-1 receptor activity. Five genes (ACACB, RIPK4, MAP2K1, TLR4 and IGF1) were defined as hub genes from the PPI network. The high expression of miR-15b-5p could play an essential part in hepatocarcinogenesis through diverse regulation approaches.

Potential clinical value and putative biological function of miR-122-5p in hepatocellular carcinoma: A comprehensive study using microarray and RNA sequencing data.

In order to determine the diagnostic efficacy of microRNA (miR)-122-5p and to identify the potential molecular signaling pathways underlying the function of miR-122-5p in hepatocellular carcinoma (HCC), the expression profiles of data collected from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO) and literature databases were analyzed, along with any associations between clinicopathological characteristics and the diagnostic value of miR-122-5p in HCC. The intersection of 12 online prediction databases and differentially expressed genes from TCGA and GEO were utilized in order to select the prospective target genes of miR-122-5p in HCC. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein-protein interaction network (PPI) analyses were subsequently performed based on the selected target genes. The average expression level of miR-122-5p was decreased in HCC patients compared with controls from TCGA database (P<0.001), and the downregulation of miR-122-5p was significantly associated with HCC tissues (P<0.001), tumor vascular invasion (P<0.001), metastasis (P=0.001), sex (P=0.006), virus infection status (P=0.001) and tissue (compared with serum; P<0.001) in cases from the GEO database. The pooled sensitivity and specificity for miR-122-5p to diagnose HCC were 0.60 [95% confidence interval (CI), 0.48-0.71] and 0.81 (95% CI, 0.70-0.89), respectively. The area under the curve (AUC) value was 0.76 (95% CI, 0.72-0.80), while in Meta-DiSc 1.4, the AUC was 0.76 (Q*=0.70). The pooled sensitivity and specificity were 0.60 (95% CI, 0.57-0.62) and 0.79 (95% CI, 0.76-0.81), respectively. A total of 198 overlapping genes were selected as the potential target genes of miR-122-5p, and 7 genes were defined as the hub genes from the PPI network. Cell division cycle 6 (CDC6), minichromosome maintenance complex component 4 (MCM4) and MCM8, which serve pivotal functions in the occurrence and development of HCC, were the most significant hub genes. The regulation of cell proliferation for cellular adhesion and the biosynthesis of amino acids was highlighted in the GO and KEGG pathway analyses. The downregulation of miR-122-5p in HCC demonstrated diagnostic value, worthy of further attention. Therefore, miR-122-5p may function as a tumor suppressor by modulating genome replication.

Long non­coding RNA HOTTIP promotes hepatocellular carcinoma tumorigenesis and development: A comprehensive investigation based on bioinformatics, qRT­PCR and meta­analysis of 393 cases.

HOTTIP functions as an independent biomarker in multiple cancers. However, the role of HOTTIP in hepatocellular carcinoma (HCC) remains unclear. In this study, we sought to investigate the HOTTIP expression in HCC and normal liver. We combined quantitative reverse transcription-polymerase chain reactions (qRT­PCR), Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA), Multi Experiment Matrix (MEM) and Oncomine database to assess the clinical role and the potential molecular mechanism of HOTTIP in HCC. Furthermore, a meta­analysis was performed to evaluate the relationship between HOTTIP and HCC tumorigenesis and development. Additionally, bioinformatics analysis, which contained Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and network analysis, were applied to investigate the underlying functions, pathways and networks of the potential genes. HOTTIP was obviously upregulated in HCC. A statistically significant higher expression of HOTTIP was found in TNM (III +Ⅳ), age (≥60), sex (male), race (white) and cirrhosis (no) compared to the control groups (P<0.05). Furthermore, the meta­analysis of 393 cases from multiple centers indicated that HOTTIP had high diagnostic value in HCC. Additionally, according to GO and KEGG analyses, we found that the most strongly enriched functional terms were gland development, transcription factor activity and extrinsic to membrane. Also, the HOTTIP co­expressed genes were significantly related to PPAR signaling pathway. We speculate that HOTTIP might play a vital part in HCC via regulating various pathways, especially PPAR signaling pathway. However, the detailed mechanism should be confirmed by functional experiments.