Overexpression of IRF9 confers resistance to antimicrotubule agents in breast cancer cells
CANCER RESEARCH
Authors: Luker, KE; Pica, CM; Schreiber, RD; Piwnica-Worms, D
Abstract
yIRF9/p48/ISGF3 gamma (IRF9) is an IFN regulatory factor that mediates signaling by type I IFNs (IFN alpha and IFN beta). After single-step selection of breast adenocarcinoma cells in paclitaxel, differential display and single gene analysis demonstrated that transcriptional activation of IRF9 and other IFN-responsive genes, independent of IFN, corresponded with resistance to antimicrotubule agents. Transient overexpression of IRF9 reproduced the drug-resistance phenotype and induced expression of ITN-responsive genes. However, drug resistance was not induced by overexpression of Stat1 or Stat2, or treatment with IFN alpha per se. Using a donor-matched array of cDNA prepared from human tumor and normal tissue from a variety of organs, we observed overexpression of IRF9 in approximately one-half of breast and uterine tumors, which indicated that IRF9 may be important in signaling in these tumor types. These data identify a novel IFN-independent role for IRF9 in the development of resistance to antimicrotubule agents in breast tumor cells and may link downstream mediators of IFN signaling to drug resistance in human cancers.
Geosporobacter ferrireducens sp nov., an anaerobic iron-reducing bacterium isolated from an oil-contaminated site
ANTONIE VAN LEEUWENHOEK INTERNATIONAL JOURNAL OF GENERAL AND MOLECULAR MICROBIOLOGY
Authors: Hong, Heeji; Kim, So-Jeong; Min, Ui-Gi; Lee, Yong-Jae; Kim, Song-Gun; Jung, Man-Young; Seo, Yong-Seok; Rhee, Sung-Keun
Abstract
In this study, an alkaliphilic and heterotrophic iron-reducing bacterial strain, IRF9(T), was isolated from an oil-contaminated soil in the Republic of Korea. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain IRF9(T) belongs to the genus Geosporobacter in the family Clostridiaceae and is most closely related to Geosporobacter subterraneus VNs68(T) (96.9 % sequence similarity). Cells of strain IRF9(T) were observed to be straight or curved rod-shaped, motile and Gram-negative. Optimal growth of strain IRF9(T) was observed at pH 9.0-9.5 and 40 A degrees C. The strain was found to grow within pH and temperature ranges of 6.5-10.0 and 25-45 A degrees C, respectively. NaCl was not required for growth. Fe(III), but not sulfate, thiosulfate or elemental sulfur can be used by strain IRF9(T) as an electron acceptor. A limited number of carbohydrates and amino acids, including d-glucose, d-fructose, d-mannitol, d-ribose and l-arginine, support growth of strain IRF9(T). The main fatty acids (> 10 %) of strain IRF9(T) were identified as C-14:0 (18.4 %), C-16:1 cis9 (13.6 %), C-16:0 (12.4 %) and C-16:0 dimethyl acetal (17.7 %). Major respiratory quinone was identified as menaquinone MK-5 (V-H-2). The main polar lipids were found to be phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The DNA G+C content of strain IRF9(T) was determined to be 37.2 mol%, which is lower than that of G. subterraneus VNs68(T) (42.2 mol%). Based on phenotypic, chemotaxonomic, and phylogenetic studies, we conclude that strain IRF9(T) (=JCM 19987(T) = KCTC 15395(T)) represents a new species of the genus Geosporobacter, for which we propose the name Geosporobacter ferrireducens sp. nov.