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Soroceanu L.,California Pacific Medical Center Research Institute | Matlaf L.,California Pacific Medical Center Research Institute | Khan S.,California Pacific Medical Center Research Institute | Akhavan A.,California Pacific Medical Center Research Institute | And 14 more authors.
Cancer Research | Year: 2015

Glioblastoma (GBM) is the most common and aggressive human brain tumor. Human cytomegalovirus (HCMV) immediate-early (IE) proteins that are endogenously expressed in GBM cells are strong viral transactivators with oncogenic properties. Here, we show how HCMV IEs are preferentially expressed in glioma stem-like cells (GSC), where they colocalize with the other GBM stemness markers, CD133, Nestin, and Sox2. In patient-derived GSCs that are endogenously infected with HCMV, attenuating IE expression by an RNAi-based strategy was sufficient to inhibit tumorsphere formation, Sox2 expression, cell-cycle progression, and cell survival. Conversely, HCMV infection of HMCV-negative GSCs elicited robust self-renewal and proliferation of cells that could be partially reversed by IE attenuation. In HCMV-positive GSCs, IE attenuation induced a molecular program characterized by enhanced expression of mesenchymal markers and proinflammatory cytokines, resembling the therapeutically resistant GBM phenotype. Mechanistically, HCMV/IE regulation of Sox2 occurred via inhibition of miR-145, a negative regulator of Sox2 protein expression. In a spontaneous mouse model of glioma, ectopic expression of the IE1 gene (UL123) specifically increased Sox2 and Nestin levels in the IE1-positive tumors, upregulating stemness and proliferation markers in vivo. Similarly, human GSCs infected with the HCMV strain Towne but not the IE1-deficient strain CR208 showed enhanced growth as tumorspheres and intracranial tumor xenografts, compared with mock-infected human GSCs. Overall, our findings offer new mechanistic insights into how HCMV/IE control stemness properties in GBM cells. © 2015 American Association for Cancer Research.

Wagner L.A.,University of Utah | Wang S.,University of Utah | Wayner E.A.,Ben and Catherine Ivy Center for Advanced Brain Tumor Treatment | Christensen C.,Biofire Diagnostics, Inc. | And 7 more authors.
Human Antibodies | Year: 2013

BACKGROUND: c3orf75 is a conserved open reading frame within the human genome and has recently been identified as the Elongator subunit, ELP6 [1]. The Elongator enzyme complex has diverse roles, including translational control, neuronal development, cell migration and tumorigenicity [2]. OBJECTIVE: To identify genes expressed early in human eosinophil development. METHODS: Eosinophilopoiesis was investigated by gene profiling of IL-5 stimulated CD34+ cells; ELP6 mRNA is upregulated. A monoclonal antibody was raised to the recombinant protein predicted by the open reading frame. RESULTS: ELP6 transcripts are upregulated in a human tissue culture model of eosinophil development during gene profiling experiments. Transcripts are expressed in most tissue types, as shown by reverse-transcriptase PCR. Western blot experiments show that human ELP6 is a 30 kDa protein expressed in the bone marrow, as well as in many other tissues. Flow cytometry experiments of human bone marrow mononuclear cells show that ELP6 is expressed intracellularly, in developing and mature human neutrophils, eosinophils and monocytes. CONCLUSIONS: ELP6 is expressed intracellularly in developing and mature granulocytes and monocytes but not in lymphocytes and erythrocytes. © 2013 - IOS Press and the authors. All rights reserved.

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