Identification of Novel Mycobacterial Inhibitors Against Mycobacterial Protein Kinase G

Protein kinase G (PknG) is a eukaryotic-like serine/threonine kinase that is expressed by Mycobacterium tuberculosis and promotes survival of mycobacteria in host macrophages by suppressing phagosome-lysosome fusion. Thus, compounds showing inhibitory activity against PknG are promising anti-mycobacterial agents. We therefore aimed to develop anti-mycobacterial agents by identifying new PknG inhibitors. A luciferase-based PknG kinase assay was used to screen potential inhibitors of PknG. We found that four compounds, namely AZD7762, R406, R406-free base, and CYC116, inhibited PknG activities. AZD7762, R406, and R406-free base promoted transfer of mycobacteria to lysosomes. These compounds also inhibited survival of M. bovis Bacillus Calmette–Guérin (BCG) inside human macrophages. Furthermore, R406 and R406-free base showed bactericidal activity against BCG in infected human macrophages without cytotoxicity. The PknG inhibitors identified in this study by the luciferase-based PknG kinase assay may be promising leads for the development of anti-mycobacterial agents

Isolation and characterization of human breast cancer cells with SOX2 promoter activity

Sex determining region Y-box 2 (SOX2) is well known as one of the "sternness" factors and is often expressed in cancers including breast cancer. In this study, we developed a reporter system using fluorescent protein driven by the promoter for SOX2 gene to detect and isolate living SOX2-positive cells. Using this system, we determined that SOX2 promoter activities were well correlated with SOX2 mRNA expression levels in 5 breast cancer cell lines, and that the cell population with positive SOX2 promoter activity (pSp-T+) isolated from one of the 5 cell lines, MCF-7 cells, showed a high SOX2 protein expression and high sphere-forming activity compared with very low promoter activity (pSp-Tlow/-). The pSp-T(+)pbpulation expressed higher mRNA levels of several stemness-related genes such as CD44, ABCB1, NANOG and TWIST] than the pSp-Tlow/- population whereas the two populations expressed CD24 at similar levels. These results suggest that the cell population with SOX2 promoter activity contains cancer stem cell (CSC)-like cells which show different expression profiles from those of CSC-marker genes previously recognized in human breast cancers. (C) 2013 Elsevier Inc. All rights reserved

Epstein-Barr Virus (EBV)-associated Gastric Carcinoma

The ubiquitous Epstein-Barr virus (EBV) is associated with several human tumors, which include lymphoid and epithelial malignancies. It is known that EBV persistently infects the memory B cell pool of healthy individuals by activating growth and survival signaling pathways that can contribute to B cell lymphomagenesis.  Although the monoclonal proliferation of EBV-infected cells can be observed in epithelial tumors, such as nasopharyngeal carcinoma and EBV-associated gastric carcinoma, the precise role of EBV in the carcinogenic progress is not fully understood. This review features characteristics and current understanding of EBV-associated gastric carcinoma. EBV-associated gastric carcinoma comprises almost 10% of all gastric carcinoma cases and expresses restricted EBV latent genes (Latency I). Firstly, definition, epidemiology, and clinical features are discussed. Then, the route of infection and carcinogenic role of viral genes are presented.  Of particular interest, the association with frequent genomic CpG methylation and role of miRNA for carcinogenesis are topically discussed. Finally, the possibility of therapies targeting EBV-associated gastric carcinoma is proposed.&#160

Herpesviral microRNAs in Cellular Metabolism and Immune Responses

The microRNAs (miRNAs) function as a key regulator in many biological processes through post-transcriptional suppression of messenger RNAs. Recent advancements have revealed that miRNAs are involved in many biological functions of cells. Not only host cells, but also some viruses encode miRNAs in their genomes. Viral miRNAs regulate cell proliferation, differentiation, apoptosis, and the cell cycle to establish infection and produce viral progeny. Particularly, miRNAs encoded by herpes virus families play integral roles in persistent viral infection either by regulation of metabolic processes or the immune response of host cells. The life-long persistent infection of gamma herpes virus subfamilies, such as Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus, induces host cells to malignant transformation. The unbalanced metabolic processes and evasion from host immune surveillance by viral miRNAs are induced either by direct targeting of key proteins or indirect regulation of multiple signaling pathways. We provide an overview of the pathogenic roles of viral miRNAs in cellular metabolism and immune responses during herpesvirus infection

Epstein-Barr Virus (EBV)-associated Gastric Carcinoma

The ubiquitous Epstein-Barr virus (EBV) is associated with several human tumors, which include lymphoid and epithelial malignancies. It is known that EBV persistently infects the memory B cell pool of healthy individuals by activating growth and survival signaling pathways that can contribute to B cell lymphomagenesis. Although the monoclonal proliferation of EBV-infected cells can be observed in epithelial tumors, such as nasopharyngeal carcinoma and EBV-associated gastric carcinoma, the precise role of EBV in the carcinogenic progress is not fully understood. This review features characteristics and current understanding of EBV-associated gastric carcinoma. EBV-associated gastric carcinoma comprises almost 10% of all gastric carcinoma cases and expresses restricted EBV latent genes (Latency I). Firstly, definition, epidemiology, and clinical features are discussed. Then, the route of infection and carcinogenic role of viral genes are presented. Of particular interest, the association with frequent genomic CpG methylation and role of miRNA for carcinogenesis are topically discussed. Finally, the possibility of therapies targeting EBV-associated gastric carcinoma is proposed

General Features and Novel Gene Signatures That Identify Epstein-Barr Virus-Associated Epithelial Cancers

Epstein-Barr virus (EBV) is associated with various types of human malignancies, including nasopharyngeal carcinoma (NPC), EBV-associated gastric carcinoma (EBVaGC), and oral squamous cell carcinoma (OSCC). The present study aimed to identify gene signatures and common signaling pathways that can be used to predict the prognosis of EBV-associated epithelial cancers (EBVaCAs) by performing an integrated bioinformatics analysis of cell lines and tumor tissues. We identified 12 differentially expressed genes (DEGs) in the EBVaCA cell lines. Among them, only four DEGs, including BAMBI, SLC26A9, SGPP2, and TMC8, were significantly upregulated. However, SLC26A9 and TMC8, but not BAMBI and SGPP2, were significantly upregulated in EBV-positive tumor tissues compared to EBV-negative tumor tissues. Next, we identified IL6/JAK/STAT3 and TNF-α/NF-κB signaling pathways as common hallmarks of EBVaCAs. The expression of key genes related to the two hallmarks was upregulated in both EBV-infected cell lines and EBV-positive tumor tissues. These results suggest that SLC26A9 and TMC8 might be gene signatures that can effectively predict the prognosis of EBVaCAs and provide new insights into the molecular mechanisms of EBV-driven epithelial cancers