CCAAT/enhancer-binding protein alpha (CEBPA) gene haploinsufficiency does not alter hematopoiesis or induce leukemia in Lck-CALM/AF10 transgenic mice

Although rare, CALM/AF10 is a chromosomal rearrangement found in immature T-cell acute lymphoblastic leukemia (T-ALL), acute myeloid leukemia, and mixed phenotype acute leukemia of T/myeloid lineages with poor prognosis. Moreover, this translocation is detected in 50% of T-ALL patients with gamma/delta T cell receptor rearrangement, frequently associated with low expression of transcription factor CCAAT/enhancer-binding protein alpha (CEBPA). However, the relevance of CEBPA low expression for CALM/AF10 leukemogenesis has not yet been evaluated. We generated double mutant mice, which express the Lck-CALM/AF10 fusion gene and are haploinsufficient for the Cebpa gene. To characterize the hematopoiesis, we quantified hematopoietic stem cells, myeloid progenitor cells, megakaryocyte-erythrocyte progenitor cells, common myeloid progenitor cells, and granulocyte-macrophage progenitor cells. No significant difference was detected in any of the progenitor subsets. Finally, we tested if Cebpa haploinsufficiency would lead to the expansion of Mac-1+/B220+/c-Kit+ cells proposed as the CALM/AF10 leukemic progenitor. Less than 1% of bone marrow cells expressed Mac-1, B220, and c-Kit with no significant difference between groups. Our results showed that the reduction of Cebpa gene expression in Lck-CALM/AF10 mice did not affect their hematopoiesis or induce leukemia. Our data corroborated previous studies suggesting that the CALM/AF10 leukemia-initiating cells are early progenitors with lymphoid/myeloid differentiating potential.

Novel Mutations in CEBPA in Korean Patients with Acute Myeloid Leukemia with a Normal Karyotype

Mutations in the transcription factor CCAAT/enhancer binding protein alpha gene (CEBPA) are found in 5-14% of the patients with AML and have been associated with a favorable clinical outcome. In this study, we aimed to assess the frequencies and characteristics of mutations in CEBPA. Between 2006 and 2009, CEBPA mutations were assessed using archival DNA samples obtained from 30 consecutive adult patients diagnosed with AML with a normal karyotype at our institution. CEBPA mutations were detected using direct sequencing analyses. These mutations were detected and described with reference to GenBank Accession No. NM_004364.3. In our series, CEBPA mutations were detected in 4 patients (13.3%). These mutations occurred as double mutations in all 4 patients. Among the 8 mutant alleles, 5 were novel (c.179_180dupCG, c.50_53delGCCA, c.178_182delACGTinsTTT, c.243_244insGTCG, and c.923_924insCTC). The frequency of occurrence of CEBPA mutations in Korean patients with AML is comparable to that in previous reports. Long-term follow-up data from a larger series of patients with comprehensive molecular profiling are needed to delineate the prognostic implications.

Anti-obesity effects of Lysimachia foenum-graecum characterized by decreased adipogenesis and regulated lipid metabolism

Lysimachia foenum-graecum has been used as an oriental medicine with anti-inflammatory effect. The anti-obesity effect of L. foenum-graecum extract (LFE) was first discovered in our screening of natural product extract library against adipogenesis. To characterize its anti-obesity effects and to evaluate its potential as an anti-obesity drug, we performed various obesity-related experiments in vitro and in vivo. In adipogenesis assay, LFE blocked the differentiation of 3T3-L1 preadipocyte in a dose-dependent manner with an IC50 of 2.5 microg/ml. In addition, LFE suppressed the expression of lipogenic genes, while increasing the expression of lipolytic genes in vitro at 10 microg/ml and in vivo at 100 mg/kg/day. The anti-adipogenic and anti-lipogenic effect of LFE seems to be mediated by the inhibition of PPARgamma and C/EBPalpha expression as shown in in vitro and in vivo, and the suppression of PPARgamma activity in vitro. Moreover, LFE stimulated fatty acid oxidation in an AMPK-dependent manner. In high-fat diet (HFD)-induced obese mice (n = 8/group), oral administration of LFE at 30, 100, and 300 mg/kg/day decreased total body weight gain significantly in all doses tested. No difference in food intake was observed between vehicle- and LFE-treated HFD mice. The weight of white adipose tissues including abdominal subcutaneous, epididymal, and perirenal adipose tissue was reduced markedly in LFE-treated HFD mice in a dose-dependent manner. Treatment of LFE also greatly improved serum levels of obesity-related biomarkers such as glucose, triglycerides, and adipocytokines leptin, adiponectin, and resistin. All together, these results showed anti-obesity effects of LFE on adipogenesis and lipid metabolism in vitro and in vivo and raised a possibility of developing LFE as anti-obesity therapeutics.