GRIM-1, a Novel Growth Suppressor, Inhibits rRNA Maturation by Suppressing Small Nucleolar RNAs

We have recently isolated novel IFN-inducible gene, Gene associated with Retinoid-Interferon-induced Mortality-1 (GRIM-1), using a genetic technique. Moderate ectopic expression of GRIM-1 caused growth inhibition and sensitized cells to retinoic acid (RA)/IFN-induced cell death while high expression caused apoptosis. GRIM-1 depletion, using RNAi, conferred a growth advantage. Three protein isoforms (1α, 1β and 1γ) with identical C-termini are produced from GRIM-1 mRNA. We show that GRIM-1 isoforms interact with NAF1 and DKC1, two essential proteins required for box H/ACA sno/sca RNP biogenesis and suppresses box H/ACA RNA levels in mammalian cells by delocalizing NAF1. Suppression of these small RNAs manifests as inefficient rRNA maturation and growth suppression. Interestingly, yeast Shq1p also caused growth suppression in mammalian cells. Consistent with its growth-suppressive property, GRIM-1 expression is lost in a number of human primary prostate tumors. Our observations support a recent study that GRIM-1 might act as a co-tumor suppressor in the prostate

Death-associated Protein Kinase-1 Expression and Autophagy in Chronic Lymphocytic Leukemia Are Dependent on Activating Transcription Factor-6 and CCAAT/Enhancer-binding Protein-β

Expression of DAPK1, a critical regulator of autophagy and apoptosis, is lost in a wide variety of tumors, although the mechanisms are unclear. A transcription factor complex consisting of ATF6 (an endoplasmic reticulum-resident factor) and C/EBP-β is required for the IFN-γ-induced expression of DAPK1. IFN-γ-induced proteolytic processing of ATF6 and phosphorylation of C/EBP-β are obligatory for the formation of this transcriptional complex. We report that defects in this pathway fail to control growth of chronic lymphocytic leukemia (CLL). Consistent with these observations, IFN-γ and chemotherapeutics failed to activate autophagy in CLL patient samples lacking ATF6 and/or C/EBP-β. Together, these results identify a molecular basis for the loss of DAPK1 expression in CLL

Tunicamycin induced endoplasmic reticulum stress promotes apoptosis of prostate cancer cells by activating mTORC1

Studies suggest that tunicamycin may work as a therapeutic drug to cancer cells by inducing stress in the endoplasmic reticulum (ER) through unfolded protein response (UPR) and thereby promoting apoptosis. However, mechanisms of the prolonged activation of the UPR under sustained ER stress in the regulation of cell apoptosis are largely unknown. To delineate the role of candidate genes in the apoptotic process under ER stress and to search for new therapeutic strategies to treat metastatic castration resistant prostate cancer, we performed whole genome expression microarray analysis in tunicamycin treated metastatic androgen-insensitive prostate cancer cells, PC-3. Among several induced genes, the expression of eNOS (NOS3) gene was remarkably high. The increased expression of eNOS activates mTORC1 through RagC. This results into an accumulation of p62 (SQSTM1) which facilitates aggregation of ubiquitinated protein thus compromising clearance of misfolded toxic protein aggregates. Lastly, association of p62 proteins and misfolded proteins promote reactive oxygen species (ROS) mediated mitochondrial apoptosis. Overall, our data demonstrate that tunicamycin induced ER stress promotes prostate cancer cell death by activating mTORC1 through eNOS-RagC pathway

Down-regulation of the transcriptional mediator subunit Med1 contributes to the loss of expression of metastasis-associateddapk1in human cancers and cancer cells

U ovom radu proveden je proračun godišnje isporučene i primarne energije sunčanog toplovodnog sustava za grijanje prostora i pripremu potrošne tople vode. Proračun je proveden za referentnu obiteljsku kuću, pri dvije različite razine potrebne godišnje toplinske energije za grijanje, te za klimatska područja Zagreba i Splita, kako bi se mogao ispitati utjecaj toplinske ovojnice zgrade, ali i klimatskih uvjeta na potrošnju energije. Metodologija proračuna omogućuje troškovnu optimizaciju sunčanog toplovodnog sustava varijacijom elemenata podsustava predaje te pomoćnog generatora topline. Napravljena je usporedba dobivenih rezultata s onima izračunatim prema novim prijedlozima normi iz serije prEN 15316.In this paper, the calculation of the annual delivered and primary energy of solar hot water systems for space heating and domestic hot water has been conducted. The calculation has been made for reference dwelling at two different levels of energy required for space heating, as well as for two climate areas, in order to investigate the influence of building envelope, but also of weather conditions on energy consumption. Calculation methodology enables cost optimization of solar system by changing emission subsystem elements or auxiliary heat source. A comparison of the results with those calculated according to new proposals of the norms from series prEN 15316 has been made

Critical Role for Transcription Factor C/EBP-β in Regulating the Expression of Death-Associated Protein Kinase 1▿ †

Transcription factor C/EBP-β regulates a number of physiological responses. During an investigation of the growth-suppressive effects of interferons (IFNs), we noticed that cebpb−/− cells fail to undergo apoptosis upon gamma IFN (IFN-γ) treatment, compared to wild-type controls. To examine the basis for this response, we have performed gene expression profiling of isogenic wild-type and cebpb−/− bone marrow macrophages and identified a number of IFN-γ-regulated genes that are dependent on C/EBP-β for their expression. These genes are distinct from those regulated by the JAK-STAT pathways. Genes identified in this screen appear to participate in various cellular pathways. Thus, we identify a new pathway through which the IFNs exert their effects on cellular genes through C/EBP-β. One of these genes is death-associated protein kinase 1 (dapk1). DAPK1 is critical for regulating the cell cycle, apoptosis, and metastasis. Using site-directed mutagenesis, RNA interference, and chromatin immunoprecipitation assays, we show that C/EBP-β binds to the promoter of dapk1 and is required for the regulation of dapk1. Both mouse dapk1 and human dapk1 exhibited similar dependences on C/EBP-β for their expression. The expression of the other members of the DAPK family occurred independently of C/EBP-β. Members of the C/EBP family of transcription factors other than C/EBP-β did not significantly affect dapk1 expression. We identified two elements in this promoter that respond to C/EBP-β. One of these is a consensus C/EBP-β-binding site that constitutively binds to C/EBP-β. The other element exhibits homology to the cyclic AMP response element/activating transcription factor binding sites. C/EBP-β binds to this site in an IFN-γ-dependent manner. Inhibition of ERK1/2 or mutation of an ERK1/2 site in the C/EBP-β protein suppressed the IFN-γ-induced response of this promoter. Together, our data show a critical role for C/EBP-β in a novel IFN-induced cell growth-suppressive pathway via DAPK1

Potential cis-acting regulatory elements in the LPS responsive region of the murine <i>SerpinB2</i> promoter

<p>−<b>563/−1.</b> Mouse and human nucleotide sequences were aligned using Clustal W software. <i>Cis</i>-acting elements conserved between the human and murine SerpinB2 promoters are boxed and labeled. AP-1 =  activator protein 1; C/EBP =  CCAAT enhancer binding protein; CRE = cAMP response element; Oct1 =  octamer transcription factor 1/POU2F1; PU.1 =  purine box binding protein 1. The putative transcription initiation site (tis) is indicated and exon 1 is presented in uppercase. The location of the 5' ends of the −539, −189 and −87 reporter constructs are also shown.</p

Identification of <i>cis</i>-acting elements required for the LPS-responsiveness of the murine <i>SerpinB2</i> promoter.

<p><i>(A)</i> Schematic representation of the −539/+92 region of the murine <i>SerpinB2</i> promoter with the location of candidate <i>cis</i>-acting regulatory elements indicated with <i>boxes</i>. The location of the 5′ ends of the −539, −189 and −87 reporter constructs is also shown. Positions of murine <i>SerpinB2</i> proximal promoter-specific primers, 338/−315 and −5/+19 used in ChIP assays are indicated. <i>(B)</i> RAW 264.7 macrophages were transiently transfected with the indicated murine <i>SerpinB2</i> promoter-luciferase reporter constructs and either left untreated or treated with 100 ng/ml LPS for 16 hrs. The results show relative luciferase activity following LPS treatment and represent the mean and SEM of 4–7 independent experiments.</p