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Background: High expression of inhibitor of DNA binding 1 (ID1) correlates with poor prognosis in colorectal cancer (CRC). Aberrant enhancer activation in regulating ID1 transcription is limited. Methods: Immunohistochemistry (IHC), quantitative RT-PCR (RT-qPCR) and Western blotting (WB) were used to determine the expression of ID1. CRISPR-Cas9 was used to generate ID1 or enhancer E1 knockout cell lines. Dual-luciferase reporter assay, chromosome conformation capture assay and ChIP-qPCR were used to determine the active enhancers of ID1. Cell Counting Kit 8, colony-forming, transwell assays and tumorigenicity in nude mice were used to investigate the biological functions of ID1 and enhancer E1. Results: Human CRC tissues and cell lines expressed a higher level of ID1 than normal controls. ID1 promoted CRC cell proliferation and colony formation. Enhancer E1 actively regulated ID1 promoter activity. Signal transducer and activator of transcription 3 (STAT3) bound to ID1 promoter and enhancer E1 to regulate their activity. The inhibitor of STAT3 Stattic attenuated ID1 promoter and enhancer E1 activity and the expression of ID1. Enhancer E1 knockout down-regulated ID1 expression level and cell proliferation in vitro and in vivo. Conclusions: Enhancer E1 is positively regulated by STAT3 and contributes to the regulation of ID1 to promote CRC cell progression and might be a potential target for anti-CRC drug studies. [ABSTRACT FROM AUTHOR]

The leukocyte common antigen CD45 is a transmembrane phosphatase expressed on all nucleated hemopoietic cells, and the expression levels of its splicing isoforms are closely related to the development and function of lymphocytes. PEBP1P3 is a natural antisense transcript from the opposite strand of CD45 intron 2 and is predicted to be a noncoding RNA. The genotype-tissue expression and quantitative PCR data suggested that PEBP1P3 might be involved in the regulation of expression of CD45 splicing isoforms. To explore the regulatory mechanism of PEBP1P3 in CD45 expression, DNA methylation and histone modification were detected by bisulfate sequencing PCR and chromatin immunoprecipitation assays, respectively. The results showed that after the antisense RNA PEBP1P3 was knocked down by RNA interference, the DNA methylation of CD45 intron 2 was decreased and histone H3K9 and H3K36 trimethylation at the alternative splicing exons of CD45 DNA was increased. Knockdown of PEBP1P3 also increased the binding levels of chromatin conformation organizer CTCF at intron 2 and the alternative splicing exons of CD45. The present results indicate that the natural antisense RNA PEBP1P3 regulated the alternative splicing of CD45 RNA, and that might be correlated with the regulation of histone modification and DNA methylation. [ABSTRACT FROM AUTHOR]

The human immune response is a complex process that responds to numerous exogenous antigens in preventing infection by microorganisms, as well as to endogenous components in the surveillance of tumors and autoimmune diseases, and a great number of molecules are necessary to carry the functional complexity of immune activity. Alternative splicing of pre-mRNA plays an important role in immune cell development and regulation of immune activity through yielding diverse transcriptional isoforms to supplement the function of limited genes associated with the immune reaction. In addition, multiple factors have been identified as being involved in the control of alternative splicing at the cis, trans, or co-transcriptional level, and the aberrant splicing of RNA leads to the abnormal modulation of immune activity in infections, immune diseases, and tumors. In this review, we summarize the recent discoveries on the generation of immune-associated alternative splice variants, clinical disorders, and possible regulatory mechanisms. We also discuss the immune responses to the neoantigens produced by alternative splicing, and finally, we issue some alternative splicing and immunity correlated questions based on our knowledge. [ABSTRACT FROM AUTHOR]

Prostate cancer is a common carcinoma in males, the development of which involves the androgen receptor (AR) as a key regulator. AR transactivation induces the high expression of androgen-regulated genes, including transmembrane protease serine 2 (TMPRSS2) and long noncoding RNA prostate cancer-associated transcript 38 (PRCAT38). PRCAT38 and TMPRSS2 are both located on chromosome 21, separated by a series of enhancers. PRCAT38 is a prostate-specific long noncoding RNA that is highly expressed in cancer tissue as compared to normal tissue. Here, we show chromatin looping by enhancers E1 and E2 with the promoters for PRCAT38 and TMPRSS2, indicating the co-regulation of PRCAT38 and TMPRSS2 by the same enhancers. The knockout of enhancer E1 or E2 simultaneously impaired the transcription of PRCAT38 and TMPRSS2 and inhibited cell growth and migration. Moreover, the loop formation and enhancer activity were mediated by AR/FOXA1 binding and the activity of acetyltransferase p300. Our findings demonstrate the utilization of shared enhancers in the joint regulation of two oncogenes in prostate cancer cells. [ABSTRACT FROM AUTHOR]

Mitochondrial dysfunction is known to play a critical role in the development of cardiomyocyte death during acute myocardial infarction (AMI). However, the exact mechanisms underlying this dysfunction are still under investigation. Adenine nucleotide translocase 2 (ANT2) is a key functional protein in mitochondria. We aimed at exploring the potential benefits of ANT2 inhibition against AMI. We utilized an oxygen-glucose deprivation (OGD) cell model and an AMI mice model to detect cardiomyocyte injury. We observed elevated levels of reactive oxygen species (ROS), disrupted mitochondrial membrane potential (MMP), and increased apoptosis due to the overexpression of ANT2. Additionally, we discovered that ANT2 is involved in myocardial apoptosis by activating the mTOR (mechanistic target of rapamycin kinase)-dependent PGC-1α (PPARG coactivator 1 alpha) pathway, establishing a novel feedback loop during AMI. In our experiments with AC16 cells under OGD conditions, we observed protective effects when transfected with ANT2 siRNA and miR-1203. Importantly, the overexpression of ANT2 counteracted the protective effect resulting from miR-1203 upregulation in OGD-induced AC16 cells. All these results supported that the inhibition of ANT2 could alleviate myocardial cell injury under OGD conditions. Based on these findings, we propose that RNA interference (RNAi) technology, specifically miRNA and siRNA, holds therapeutic potential by activating the ANT2/mTOR/PGC-1α feedback loop. This activation could help mitigate mitochondria-mediated injury in the context of AMI. These insights may contribute to the development of future clinical strategies for AMI.