Titanium dioxide nanoparticles (TiO2 NPs) have potential applications as food additives, but concerns persist about their safety. Children are identified as having the highest exposure and may face the greatest health risks. However, the toxicological sensitivity of TiO2 NPs in different ages is not clear. Here, a comparative toxicity study of TiO2 NPs in 3-week (youth) and 8-week (adult) old Sprague-Dawley rats is reported following oral exposure at doses of 0, 10, 50, 200 mg kg(-1) body weight per day for 30 days. The organ mass and histology, blood biochemistry and redox state, intestinal function, and biodistribution of NPs are characterized. The results show that TiO2 NPs induce different toxic effects on young and adult rats. The liver edema, heart injuries and non-allergic mast cell activation in stomach tissues are found in young rats. On the other hand, only slight injury in the liver and kidney and decreased intestinal permeability and molybdenum contents are found in adult rats. Furthermore, TiO2 NP exposure can provoke reductive stress (i.e., increased reduced glutathione (GSH)/oxidized glutathione (GSSG) ratios) in plasmas through enhancing the glucose and GSH levels in young rats or reducing the glutathione peroxidase (GSH-Px) acitivity and GSSG levels in adult rats. These results suggest that different ages may require different biomarkers for identifying and monitoring oral toxicity of nanoparticles.

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Insulin-like growth factor 2 (IGF2) mRNA-binding protein 2 (IGF2BP2) is a post-transcriptional regulatory factor implicated in mRNA localization, stability, and translational control. However, the role of IGF2BP2 regulation in colorectal cancer (CRC) and its underlying mechanism remain elusive. In this study, we found that IGF2BP2 expression is markedly increased in CRC tissues. Notably, IGF2BP2 overexpression strikingly enhanced the proliferation and survival of CRC cells in vitro, whereas its shRNA-mediated silencing resulted in the opposite. Molecular function analyses revealed that IGF2BP2 regulates RAF1 expression through blocking its degradation by miR-195. These results identify IGF2BP2 as a post-transcriptional regulatory mRNAbinding factor that contributes to CRC carcinogenesis.

Altered expressions of microRNAs (miRNAs) are reported in pancreatic cancer and associate with cancer pathogenesis, apoptosis, and cell growth, thereby functioning as either tumor suppressors or oncogenes. However, the majority of studies focus on defining the regulatory functions of miRNAs, whereas few investigations are directed toward assessing how the miRNA themselves are transcriptionally regulated. In this study, integration of published multi-level expression data and bioinformatics computational approach was used to predict two regulation mechanisms: transcription factors (TF)-miRNA-mRNA regulation and long non-coding RNA(lncRNA)-miRNA-mRNA regulation. To identify differentially expressed mRNAs, miRNAs, and lncRNAs, we integrated microarray expression data in pancreatic cancer tissues and normal tissues. Combination of differentially expressed mRNAs and miRNAs with miRNA-mRNA interactions based on crosslinking and immunoprecipitation followed by high-throughput sequencing (CLIP-Seq) data from StarBas, we constructed miRNA-mRNA regulatory network. Then we constructed two regulatory networks including TF-miRNA-mRNA and lncRNA-miRNA-mRNA based on chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-Seq) data from ChIPBase and CLIP-Seq data. A total of 4385 mRNAs, 500 miRNAs, and 21 lncRNAs were differentially expressed, of which, 18 mRNAs and 54 miRNAs are with high confidence. In miRNA-mRNA regulatory network, interrelated miRNAs target 1701 differentially regulated mRNAs. By constructing regulatory network, 19miRNAs including hsa-miR-137, hsa-miR-206, hsa-miR-429, hsa-miR-320d, and hsa-miR-320c are predicted to participate in lncRNA-miRNA-mRNA regulation. Furthermore, 8 miRNAs including hsa-mir-137, hsa-mir-206, hsa-mir-429, hsa-mir-375, hsa-mir-326, hsa-mir-217, hsa-mir-301b, and hsa-mir-184 are predicted to participate in TF-miRNA-mRNA regulation. In an integrated data analysis, we reveal large-scale effects of interrelated miRNAs and provide a model for predicting the mechanism of miRNAs disorder. Our study provides a new insight into understanding the transcriptional regulation of pancreatic cancer.

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