Chromosomal translocations in lymphoid tumours can involve antigen-receptor loci undergoing V(D)J recombination. Here, we show that translocations are recovered from the joining of RAG-generated double-strand breaks (DSBs) on one chromosome to an endonuclease-generated DSB on a second chromosome, providing evidence for the participation of non-RAG DSBs in some lymphoid translocations. Surprisingly, translocations are increased in cells deficient for the nonhomologous end-joining (NHEJ) protein Ku70, implicating non-canonical joining pathways in their etiology.

Hypoxia activates autophagy, an evolutionarily conserved cellular catabolic process. Dysfunction in the autophagy pathway has been implicated in an increasing number of human diseases, including cancer. Hypoxia induces upregulation of a specific set of microRNAs (miRNAs) in a variety of cell types. Here, we describe hypoxia-induced MIR155 as a potent inducer of autophagy. Enforced expression of MIR155 increases autophagic activity in human nasopharyngeal cancer and cervical cancer cells. Knocking down endogenous MIR155 inhibits hypoxia-induced autophagy. We demonstrated that MIR155 targets multiple players in MTOR signaling, including RHEB, RICTOR, and RPS6KB2. MIR155 suppresses target-gene expression by directly interacting with their 3′ untranslated regions (UTRs), mutations of the binding sites abolish their MIR155 responsiveness. Furthermore, by downregulating MTOR signaling, MIR155 also attenuates cell proliferation and induces G1/S cell cycle arrest. Collectively, these data present a new role for MIR155 as a key regulator of autophagy via dysregulation of MTOR pathway.

MiR-210 is up-regulated in multiple cancer types but its function is disputable and further investigation is necessary. Using a bioinformatics approach, we identified the putative target genes of miR-210 in hypoxia-induced CNE cells from genome-wide scale. Two functional gene groups related to cell cycle and RNA processing were recognized as the major targets of miR-210. Here, we investigated the molecular mechanism and biological consequence of miR-210 in cell cycle regulation, particularly mitosis. Hypoxia-induced up-regulation of miR-210 was highly correlated with the down-regulation of a group of mitosis-related genes, including Plk1, Cdc25B, Cyclin F, Bub1B and Fam83D. MiR-210 suppressed the expression of these genes by directly targeting their 3′-UTRs. Over-expression of exogenous miR-210 disturbed mitotic progression and caused aberrant mitosis. Furthermore, miR-210 mimic with pharmacological doses reduced tumor formation in a mouse metastatic tumor model. Taken together, these results implicate that miR-210 disturbs mitosis through targeting multi-genes involved in mitotic progression, which may contribute to its inhibitory role on tumor formation.

Gene expression analysis of The Cancer Genome Atlas (TCGA) breast cancer data set show that miR-20a is upregulated in human breast cancer, especially in triple-negative subtype. Gene Set Enrichment Analysis suggests that miR-20a expression negatively correlates with the autophagy/lysosome pathway. We report here that miR-20a inhibits the basal and nutrient starvation-induced autophagic flux and lysosomal proteolytic activity, increases intracellular reactive oxygen species levels and DNA damage response by targeting several key regulators of autophagy, including BECN1, ATG16L1 and SQSTM1. Re-introduction of exogenous BECN1, ATG16L1 or SQSTM1 reverses the inhibitory effect of miR-20a on autophagy and decreases DNA damage. A negative correlation between miR-20a and its target genes is observed in breast cancer tissues. Lower levels of BECN1, ATG16L1 and SQSTM1 are more common in triple-negative cancers than in other subtypes. High levels of miR-20a also associate with higher frequency of copy-number alterations and DNA mutations in breast cancer patients. Further studies in a xenograft mouse model show that miR-20a promotes tumor initiation and tumor growth. Collectively, these findings suggest that miR-20a-mediated autophagy defect might be a new mechanism underlying the oncogenic function of miRNA during breast tumorigenesis.

Human atherosclerotic lesions overexpress the lysosomal cysteine protease cathepsin S (Cat S), one of the most potent mammalian elastases known. In contrast, atheromata have low levels of the endogenous Cat S inhibitor cystatin C compared with normal arteries, suggesting involvement of this protease in atherogenesis. The present study tested this hypothesis directly by crossing Cat S-deficient (CatS -/-) mice with LDL receptor-deficient (LDLR -/-) mice that develop atherosclerosis on a high-cholesterol diet. Compared with LDLR -/-mice, double-knockout mice (CatS -/-LDLR -/-) developed significantly less atherosclerosis, as indicated by plaque size (plaque area and intimal thickening) and stage of development. These mice also had markedly reduced content of intimal macrophages, lipids, smooth muscle cells, collagen, CD4 + T lymphocytes, and levels of IFN-γ. CatS -/-LDLR -/-monocytes showed impaired subendothelial basement membrane transmigration, and aortas from CatS -/-LDLR -/-mice had preserved elastic laminae. These findings establish a pivotal role for Cat S in atherogenesis.

Edited by Joel GottesfeldOnce it enters the host cell, herpes simplex virus type 1 (HSV-1) recruits a series of host cell factors to facilitate its life cycle. Here, we demonstrate that serine/arginine-rich splicing factor 2 (SRSF2), which is an important component of the splicing speckle, mediates HSV-1 replication by regulating viral gene expression at the transcriptional and posttranscriptional levels. Our results indicate that SRSF2 functions as a transcriptional activator by directly binding to infected cell polypeptide 0 (ICP0), infected cell polypeptide 27 (ICP27), and thymidine kinase promoters. Moreover, SRSF2 participates in ICP0 pre-mRNA splicing by recognizing binding sites in ICP0 exon 3. These findings provide insight into the functions of SRSF2 in HSV-1 replication and gene expression.Herpes simplex virus type 1 (HSV-1) is a human ␣ herpesvirus that is associated with orofacial and genital herpes infections and is related to herpes encephalitis (1). The HSV-1 genome encodes Ͼ80 genes that are transcribed by RNA polymerase II (RNAP II) 3 (2). Of these viral genes, infected cell polypeptide 0 (ICP0) plays vital roles in facilitating the HSV-1 life cycle. In HSV-1-infected cells, ICP0 prevents the antiviral response triggered by dsDNA by degrading IFI16 (3), PML, and SP100 (4). Additionally, ICP0 inhibits host IRF3 nuclear signaling to prevent the interferon production-mediated antiviral response of the infected cells (5). ICP0 enables efficient viral replication by redistributing host CCND3 to ND10 bodies, which function as precursors of replication compartments (6).ICP0 also participates in HSV-1 reactivation. In the HSV-1 genome, ICP0 dissociates HDAC1 and HDAC2 from the HDAC-RCOR1-REST-KDM1A complex to make the viral DNA accessible for transcription factor binding (7). After infection, HSV-1 uses a series of host cell factors to facilitate its life cycle. Host cell factor 1, which is a cellular transcriptional coactivator, plays a central role in initiating the expression of viral immediate early (IE) genes by interacting with numerous host cell transcription factors, such as virion protein 16 (8) and early growth response protein 1, a protein that mediates IE gene expression by binding to the key regulatory elements near the HSV-1 IE genes (9). Moreover, the DNA methyltransferase DNMT3A has been reported to promote HSV-1 replication by associating with the viral capsid protein VP26 (10).Serine/arginine-rich splicing factor 2 (SRSF2 or SC35), which is a specific well known serine/arginine-rich (SR) protein family member, is well known as a mediator of genome stability, pre-mRNA splicing, mRNA nuclear export, and translational control (11-15). SRSF2 contains an RNA recognition motif for RNA binding and a domain rich in arginine and serine residues (RS domain) that facilitates its interaction with other SR splicing factors (13).To date several studies have investigated the roles of SRSF2 in viral infection. In HIV-1 infection, SRSF2 was reported to modulate viral replication by negatively regulatin...

Canagliflozin ameliorated heart dysfunctions in HFD/ STZ-induced diabetic miceCanagliflozin inhibited lipotoxicity in palmitic acid-induced HL-1 cardiomyocytes mTOR-HIF-1a pathway mediated lipotoxicity in cardiomyocytes Canagliflozin bound to mTOR and inhibited mTOR-HIF-1a pathway

Background Persistent hyperglycemia decreases the sensitivity of insulin‐sensitive organs to insulin, owing to which cells fail to take up and utilize glucose, which exacerbates the progression of type 2 diabetes mellitus (T2DM). lncRNAs' abnormal expression is reported to be associated with the progression of diabetes and plays a significant role in glucose metabolism. Herein, we study the detailed mechanism underlying the functions of lncRNA EPB41L4A‐AS1in T2DM. Methods Data from GEO datasets were used to analyze the expression of EPB41L4A‐AS1 between insulin resistance or type 2 diabetes patients and the healthy people. Gene expression was evaluated by qRT‐PCR and western blotting. Glucose uptake was measured by Glucose Uptake Fluorometric Assay Kit. Glucose tolerance of mice was detected by Intraperitoneal glucose tolerance tests. Cell viability was assessed by CCK‐8 assay. The interaction between EPB41L4A‐AS1 and GCN5 was explored by RNA immunoprecipitation, RNA pull‐down and RNA‐FISH combined immunofluorescence. Oxygen consumption rate was tested by Seahorse XF Mito Stress Test. Results EPB41L4A‐AS1 was abnormally increased in the liver of patients with T2DM and upregulated in the muscle cells of patients with insulin resistance and in T2DM cell models. The upregulation was associated with increased TP53 expression and reduced glucose uptake. Mechanistically, through interaction with GCN5, EPB41L4A‐AS1 regulated histone H3K27 crotonylation in the GLUT4 promoter region and nonhistone PGC1β acetylation, which inhibited GLUT4 transcription and suppressed glucose uptake by muscle cells. In contrast, EPB41L4A‐AS1 binding to GCN5 enhanced H3K27 and H3K14 acetylation in the TXNIP promoter region, which activated transcription by promoting the recruitment of the transcriptional activator MLXIP. This enhanced GLUT4/2 endocytosis and further suppressed glucose uptake. Conclusion Our study first showed that the EPB41L4A‐AS1/GCN5 complex repressed glucose uptake via targeting GLUT4/2 and TXNIP by regulating histone and nonhistone acetylation or crotonylation. Since a weaker glucose uptake ability is one of the major clinical features of T2DM, the inhibition of EPB41L4A‐AS1 expression seems to be a potentially effective strategy for drug development in T2DM treatment.