Ginseng Extract Attenuates the Injury from Ultraviolet Irradiation for Female Drosophila melanogaster through the Autophagy Signaling Pathway.

Ginseng is an ancient medicinal and edible plant with many health benefits, and can serve as a drug and dietary supplement, but there are few relevant studies on its use to ease ultraviolet (UV) irradiation damage. After 0.8 mg/mL ginseng extract (GE) was added to the medium of female Drosophila melanogaster subjected to UV irradiation, the lifespan, climbing ability, sex ratio, developmental cycle, and antioxidant capacity of flies were examined to evaluate the GE function. In addition, the underlying mechanism by which GE enhances the irradiation tolerance of D. melanogaster was explored. With GE supplementation, female flies subjected to UV irradiation exhibited an extension in their lifespan, enhancement in their climbing ability, improvement in their offspring sex ratio, and restoration of the normal development cycle by increasing their antioxidant activity. Finally, further experiments indicated that GE could enhance the irradiation tolerance of female D. melanogaster by upregulating the gene expressions of SOD, GCL, and components of the autophagy signaling pathway. Finally, the performance of r4-Gal4;UAS-AMPKRNAi flies confirmed the regulatory role of the autophagy signaling pathway in mitigating UV irradiation injury.

How useful is GLUT-1 in differentiating mesothelial hyperplasia and fibrosing pleuritis from epithelioid and sarcomatoid mesotheliomas? An international collaborative study.

OBJECTIVE: Mesothelial hyperplasia (MH) and fibrosing pleuritis (FP) can be difficult to distinguish from epithelioid (MM-E) and sarcomatoid (MM-S) malignant pleural mesotheliomas. GLUT-1 has shown variable results regarding its sensitivity and specificity when used to evaluate mesothelial proliferations. We evaluated the utility of GLUT-1 immunostaining in differentiating MH and FP from MM-E and MM-S. MATERIALS AND METHODS: In this retrospective study, diagnostically well-characterized cases (MH=31, FP=29, MM-E=41, MM-S=29) were collected and manually stained for GLUT-1. All slides were visually scored by 2 pathologists; using the following system: 0%, 1+ 1-25%, 2+ 26-50% and 3+ >51% cells staining. RESULTS: All benign cases (n=60) were negative for GLUT-1 while 45 of 78 (58%) MM [21 of 41 (50%) MM-E, 21 of 29 (72%) MM-S and 3 of 3 biphasic mesothelioma (100%)] had 1+ to 3+ staining. Of the MM-E, 10 had 1+, and 11 had 2+ staining; of the MM-S 3 had 1+, 15 had 2+ and 3 had 3+ staining. Both sarcomatoid and epithelioid components of the 3 biphasic mesotheliomas revealed 1+ staining. All 5 desmoplastic MM were negative. CONCLUSIONS: Positive staining with GLUT-1 is helpful since it is present in half of MM-E and three-quarter of MM-S. Although all reactive mesothelial lesions were negative, the absence of immunoreactivity does not exclude the diagnosis of MM. As with all IHC stains used for diagnostic purposes, GLUT-1 has to be a part of a panel, and the results interpreted in the context of clinical, radiological and histological findings.

Acute myelogenous leukemia with t(6;9)(p23;q34) and marrow basophilia: an overview.

Acute myelogenous leukemia (AML) with chromosomal translocation (6;9)(p23;q34) is a rare disease with poor prognosis and distinct clinical and morphologic features. t(6;9) results in a chimeric fusion gene between DEK (6p23) and CAN/NUP214 (9q34). FLT3-ITD mutation is one of the most frequent mutations in AML and correlates with poor clinical outcome. Prevalence of FLT3-ITD is as high as 70% among patients with t(6;9) AML, and patients with t(6;9) AML and FLT3-ITD mutations usually have higher white blood cell counts, higher bone marrow blasts, and significantly lower rates of complete remission. t(6;9) is most commonly associated with AML-FAB-M2 and is considered by some researchers to be a separate disease entity because of its distinct clinical and morphologic features and poor prognostic implication. Distinct morphologic features of this entity include marrow basophilia and myelodysplasia, and immunophenotypically, the blast cells are positive for CD9, CD13, CD33, and HLA-DR; are usually positive for CD45 and CD38; and may be positive for CD15, CD34, and terminal deoxynucleotidyl transferase.

Selective basolateral localization of overexpressed Na-K-ATPase beta1- and beta2- subunits is disrupted by butryate treatment of MDCK cells.

The exclusive basolateral localization of the Na-K-ATPase in kidney epithelium is a critical aspect of nephron function. It has been suggested that mislocalized delivery of the Na-K-ATPase to the apical surface in autosomal dominant polycystic kidney disease (ADPKD) is due to the inappropriate expression of an alternative isoform of the beta-subunit, the beta(2)-isoform. It has been reported that heterologous expression of this beta(2)-isoform in Madin-Darby canine kidney (MDCK) cells results in apical delivery of the Na-K-ATPase. We created a MDCK cell line containing a tetracycline-inducible promoter and expressed either myc-tagged beta(2)- or flag-tagged beta(1)-subunits to study the surface localization of these beta-subunit isoforms in polarized monolayers. We find that the beta(2)-isoform is targeted to the basolateral surface of the plasma membrane in a polarization pattern indistinguishable from the beta(1)-isoform. However, inclusion of butyrate in the growth medium leads to upregulation of overexpressed beta(1)- or beta(2)-subunits and to their appearance at the apical surface. The beta(2)-isoform expressed in MDCK cells does not assemble into alpha(1)beta(2) heterodimers with the endogenous alpha(1). Our findings demonstrate that expression of the beta(2)-isoform does not lead to apical localization of the Na-K-ATPase in MDCK cells and provides evidence for an unexpected effect of butyrate on the trafficking of Na pump subunits.

Stable plasma membrane levels of hCTR1 mediate cellular copper uptake.

The human copper transporter 1 (hCtr1), when heterologously overexpressed in insect cells, mediates saturable Cu uptake. In mammalian expression systems, a rapid Cu-dependent internalization of hCtr1 has been reported in cells that overexpress epitope-tagged hCtr1 when exposed to Cu in the external medium. This finding led to the suggestion that such internalization may be a step in the hCtr1 transmembrane Cu transport mechanism. We have demonstrated that preincubation in Cu-containing media of sf9 cells stably expressing hCtr1 has no effect on the initial rate of Cu transport. Furthermore, Western blot analyses of fractionated sf9 cell membranes show no evidence of a regulatory Cu-dependent internalization from the plasma membrane. In similar studies on human embryonic kidney (HEK) 293 cells, we showed that incubation with Cu does not alter the initial rate of Cu uptake mediated by endogenous levels of hCtr1 compared with untreated cells. Confirmation that hCtr1 mediates this transport is provided by specific small interfering RNA-dependent decreases in hCtr1 protein levels and in Cu transport rates. Western blot analysis and confocal microscopy of human embryonic kidney 293 cells showed that the majority of hCtr1 protein is localized at the plasma membrane and no significant internalization is detected upon Cu treatment. We concluded that internalization of hCtr1 is not a required step in the transport pathway; we suggest that oligomeric hCtr1 acts as a conventional transporter providing a permeation pathway for Cu through the membrane and that internalization of endogenous hCtr1 in response to elevated extracellular Cu levels does not play a significant regulatory role in Cu homeostasis.

EVI1 induces myelodysplastic syndrome in mice.

Myelodysplasia is a hematological disease in which genomic abnormalities accumulate in a hematopoietic stem cell leading to severe pancytopenia, multilineage differentiation impairment, and bone marrow (BM) apoptosis. Mortality in the disease results from pancytopenia or transformation to acute myeloid leukemia. There are frequent cytogenetic abnormalities, including deletions of chromosomes 5, 7, or both. Recurring chromosomal translocations in myelodysplasia are rare, but the most frequent are the t(3;3)(q21;q26) and the inv(3)(q21q26), which lead to the inappropriate activation of the EVI1 gene located at 3q26. To better understand the role of EVI1 in this disease, we have generated a murine model of EVI1-positive myelodysplasia by BM infection and transplantation. We find that EVI1 induces a fatal disease of several stages that is characterized by severe pancytopenia. The disease does not progress to acute myeloid leukemia. Comparison of in vitro and in vivo results suggests that EVI1 acts at two levels. The immediate effects of EVI1 are hyperproliferation of BM cells and downregulation of EpoR and c-Mpl, which are important for terminal erythroid differentiation and platelet formation. These defects are not fatal, and the mice survive for about 10 months with compensated hematopoiesis. Over this time, compensation fails, and the mice succumb to fatal peripheral cytopenia.

EVI1 promotes cell proliferation by interacting with BRG1 and blocking the repression of BRG1 on E2F1 activity.

EVI1 is a complex protein required for embryogenesis and inappropriately expressed in many types of human myeloid leukemia. Earlier we showed that the forced expression of EVI1 in murine hematopoietic precursor cells leads to their abnormal differentiation and increased proliferation. In this report, we show that EVI1 physically interacts with BRG1 and its functional homolog BRM in mammalian cells. We found that the C terminus of EVI1 interacts strongly with BRG1 and that the central and C-terminal regions of BRG1 are involved in EVI1-BRG1 interaction. Using reporter gene assays, we demonstrate that EVI1 activates the E2F1 promoter in NIH3T3 cells but not in BRG1-negative SW13 cells. Ectopic expression of BRG1 is able to repress the E2F1 promoter in vector-transfected SW13 cells but not in EVI1-transfected SW13 cells. Finally, we show that EVI1 up-regulates cell proliferation in BRG1-positive 32Dcl3 cells but not in BRG1-negative SW13 cells. Taken together, these data support the hypothesis that the interaction with BRG1 is important for up-regulation of cell-growth by EVI1.

The leukemia-associated transcription repressor AML1/MDS1/EVI1 requires CtBP to induce abnormal growth and differentiation of murine hematopoietic cells.

The leukemia-associated fusion gene AML1/MDS1/EVI1 (AME) encodes a chimeric transcription factor that results from the (3;21)(q26;q22) translocation. This translocation is observed in patients with therapy-related myelodysplastic syndrome (MDS), with chronic myelogenous leukemia during the blast crisis (CML-BC), and with de novo or therapy-related acute myeloid leukemia (AML). AME is obtained by in-frame fusion of the AML1 and MDS1/EVI1 genes. We have previously shown that AME is a transcriptional repressor that induces leukemia in mice. In order to elucidate the role of AME in leukemic transformation, we investigated the interaction of AME with the transcription co-regulator CtBP1 and with members of the histone deacetylase (HDAC) family. In this report, we show that AME physically interacts in vivo with CtBP1 and HDAC1 and that these co-repressors require distinct regions of AME for interaction. By using reporter gene assays, we demonstrate that AME represses gene transcription by CtBP1-dependent and CtBP1-independent mechanisms. Finally, we show that the interaction between AME and CtBP1 is biologically important and is necessary for growth upregulation and abnormal differentiation of the murine hematopoietic precursor cell line 32Dc13 and of murine bone marrow progenitors.