Human aurora A is a serine-threonine kinase that controls various mitotic events. The transcription of aurora A mRNA varies throughout the cell cycle and peaks during G(2)/M. To clarify the transcriptional mechanism, we first cloned the 1.8-kb 5'-flanking region of aurora A including the first exon. Transient expression of aurora A promoter-luciferase constructs containing a series of 5'-truncated sequences or site-directed mutations identified a 7-bp sequence (CTTCCGG) from -85 to -79 as a positive regulatory element. Electromobility shift assays identified the binding of positive regulatory proteins to the CTTCCGG element. Anti-E4TF1-60 antibody generated a supershifted complex. Furthermore, coexpression of E4TF1-60 and E4TF1-53 markedly increased aurora A promoter activity. Synchronized cells transfected with the aurora A promoter-luciferase constructs revealed that the promoter activity of aurora A increased in the S phase and peaked at G(2)/M. In addition, we identified a tandem repressor element, CDE/CHR, just downstream of the CTTCCGG element, and mutation within this element led to a loss of cell cycle regulation. We conclude that the transcription of aurora A is positively regulated by E4TF1, a ubiquitously expressed ETS family protein, and that the CDE/CHR element was essential for the G(2)/M-specific transcription of aurora A.

Human herpesvirus-6 (HHV-6) encephalitis is recognized as a relatively rare, but sometimes lethal, complication of allogeneic hematopoietic stem cell transplantation (HSCT). Although the development of new diagnostic techniques and antiviral therapy has improved, the prognosis of encephalitis is still unclear. We surveyed 197 patients who underwent allogeneic HSCT between January 2004 and March 2008 at our institution, and 8 (4.0%) were diagnosed as having HHV-6 encephalitis. Five were male and 3 were female, with a median age of 40.5 years. The median onset of HHV-6 encephalitis was 18 days after HSCT, and the median duration of antiviral therapy was 41 days. The median survival time from the onset of encephalitis was 23.1 months (range: 2.7-66.7), and 3 patients died of unrelated causes (sepsis in 2 and gastrointestinal tract bleeding in 1). Cord blood transplantation was identified as the only independent risk factor (relative risk [RR] = 4.98; P = .049) by multivariate analysis. There was no statistical significance of survival after HSCT between the patients with HHV-6 encephalitis and those without HHV-6 encephalitis (the 2-year survival rate was 60% and 52.6%, respectively; P = .617). Four of the 5 surviving patients were unable to return to society because of neuropsychological disorders, including anterograde amnesia and seizures with prominent hippocampal atrophy. Although HHV-6 encephalitis occurring after HSCT is now becoming a curable complication, its sequelae, such as neuropsychological disorders, have a marked influence on the quality of life of long-term survivors. Accordingly, it is necessary to identify risk factors for HHV-6 encephalitis and establish methods for prevention of this complication.

RanBPM is a RanGTP-binding protein required for correct nucleation of microtubules. To characterize the mechanism, we searched for RanBPM-binding proteins by using a yeast two-hybrid method and isolated a cDNA encoding the ubiquitin-specific protease USP11. The full-length cDNA of USP11 was cloned from a Jurkat cell library. Sequencing revealed that USP11 possesses Cys box, His box, Asp and KRF domains, which are highly conserved in many ubiquitin-specific proteases. By immunoblotting using HeLa cells, we concluded that 921-residue version of USP11 was the predominant form, and USP11 may be a ubiquitous protein in various human tissues. By immunofluorescence assay, USP11 primarily was localized in the nucleus of non-dividing cells, suggesting an association between USP11 and RanBPM in the nucleus. Furthermore, the association between USP11 and RanBPM in vivo was confirmed not only by yeast two-hybrid assay but also by co-immunoprecipitation assays using exogenously expressed USP11 and RanBPM. We next revealed proteasome-dependent degradation of RanBPM by pulse-chase analysis using proteasome inhibitors. In fact, ubiquitinated RanBPM was detected by both in vivo and in vitro ubiquitination assays. Finally, ubiquitin conjugation to RanBPM was inhibited in a dose-dependent manner by the addition of recombinant USP11. We conclude that RanBPM was the enzymic substrate for USP11 and was deubiquitinated specifically.

To investigate an up-to-date alternative donor selection strategy, we compared the transplantation outcomes of 8/8 and 7/8 allele-matched unrelated bone marrow transplantation (UBMT) with those of umbilical cord blood transplantation (UCBT) and redefined the role of UCBT with extended analysis. Using Cox and competing risk regression analyses, we analyzed the transplantation outcomes in adult patients with acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). A total of 2472 first myeloablative transplantations between 2000 and 2010 were included (8/8 UBMT, 1001; 7/8 UBMT, 656; UCBT, 815). For acute and chronic graft-versus-host disease (GVHD) and nonrelapse mortality (NRM), we applied the combined analyses including both AML and ALL data. In the multivariate analyses, severe acute GVHD and NRM after UCBT were comparable with 8/8 UBMT, whereas those after 7/8 UBMT were significantly higher. The incidence of extensive chronic GVHD was significantly lower with UCBT compared with after 8/8 and 7/8 UBMT. With adjusted analyses for AML, UCBT and 8/8 UBMT showed similar overall survival (OS), whereas 7/8 UBMT showed inferior OS. For ALL, we found no significant difference in OS among the 3 groups. Cord blood may be the first choice alternative to 8/8 UBMT for both AML and ALL.

Heme oxygenase (HO)-1 has anti-oxidative, anti-inflammatory, and anti-apoptotic activities. However, little is known about the regulation of HO-1 in human primary acute myeloid leukemia (AML) cells. Here we investigated the expression of HO-1 in primary and established AML cells as well as other types of leukemic cells and normal monocytes, and its regulatory mechanism by the transcriptional repressor, BTB and CNC homology 1 (Bach1), and the activator, nuclear factor erythroid-derived 2 related factor 2 (Nrf2). Leukemic cell lines such as U937 expressed little HO-1, whereas most freshly isolated AML cells and monocytes expressed substantial amounts of HO-1, along with Bach1 and Nrf2. When U937 cells were treated with phorbol myristate acetate (PHA) or c-interferon, they significantly expressed both HO-1 and Bach1, like primary AML cells. Treatment with lipopolysaccharide (LPS) enhanced HO-1 expression in U937 cells but suppressed it in primary monocytes and PMA-treated U937 cells. In HO-1-expressing cells, Bach1 was localized in the cytoplasm, but Nrf2 was localized in the nuclei. Chromatin immunoprecipitation assay of these cells revealed the preferential binding of Nrf2 over Bach1 to Maf-recognition elements, the enhancer regions of the HO-1 gene. The downregulation of the HO-1 gene with siRNA increased a cytotoxic effect of an anticancer drug on primary AML cells, whereas the downregulation of Bach1 increased HO-1 expression, leading to enhanced survival. These and other results show that Bach1 plays a critical role in regulating HO-1 gene expression in AML cells and its expression suppresses their survival by downregulating HO-1 expression. Thus, functional upregulation of Bach1 is a potential strategy for antileukemic therapy. (Cancer Sci 2010; 101: 1409-1416 H eme oxygenase (HO)-1 is an inducible form of HO, which degrades heme into carbon monoxide, Fe 2+ , and biliverdin. HO-1 possesses cytoprotective properties such as antioxidative, anti-inflammatory, and anti-apoptotic functions, and these properties are beneficial to cells, tissues, organs, and organisms.(1,2) Accumulating evidence shows that induction of HO-1 is a promising strategy for the treatment of various ischemic and inflammatory diseases.(1-3) In addition, HO-1 is a potential target for cancer therapy because this enzyme gives survival and growth advantages to malignant cells by means of its anti-apoptotic activity.(4-8) Aberrant expression of HO-1 in human cancers, including hematological malignancies, is implicated in oncogenesis and chemoresistance. In primary CML cells and the CML-derived K562 cell line, constitutively expressed HO-1 has been identified as a BCR ⁄ ABL oncoprotein-dependent survival factor.(9) Other studies have shown that modulation of HO-1 expression affects cellular growth or survival of myeloid leukemia cells.(10-12) Therefore, understanding the regulatory system for the HO-1 expression in myeloid lineage cells seems to be critically important.HO-1 is induced in response to oxidative stress, and its expression is regul...