c-Abl regulates Mcl-1 gene expression in chronic lymphocytic leukemia cells

Chronic lymphocytic leukemia (CLL) is a malignancy characterized by clonal expansion of mature B cells that are resistant to apoptosis. This resistance to apoptosis partly results from Mcl-1 expression because high levels of this protein in CLL cells correlate with poor disease prognosis and resistance to chemotherapy. Thus, understanding the mechanism(s) regulating Mcl-1 expression in CLL cells may be useful in the development of new therapies for this incurable disease. In the present study, we show a strong relationship between c-Abl and Mcl-1 expression in CLL cells. We show that treatment of CLL cells with Abl-specific siRNA or with imatinib, to inhibit c-Abl activity, results in the down-regulation of Mcl-1 protein and mRNA. A major regulator of Mcl-1 gene expression is STAT3. Our data show that CLL cells expressing high levels of c-Abl also show elevated levels of phospho-STAT3, and that STAT3 phosphorylation in CLL cells is dependent on c-Abl activity. However, STAT3 phosphorylation by c-Abl requires activation of nuclear factor-κB, secretion of autocrine interleukin-6, and active protein kinase C. Taken together, our data demonstrate the mechanism involved in c-Abl regulation of Mcl-1 expression in CLL cells, and suggest that c-Abl inhibition has therapeutic application in the treatment of this disease.     

Beta-lactam antibiotics modulate T-cell functions and gene expression via covalent binding to cellular albumin

Recent work has suggested that beta-lactam antibiotics might directly affect eukaryotic cellular functions. Here, we studied the effects of commonly used beta-lactam antibiotics on rodent and human T cells in vitro and in vivo on T-cell–mediated experimental autoimmune diseases. We now report that experimental autoimmune encephalomyelitis and adjuvant arthritis were significantly more severe in rats treated with cefuroxime and other beta-lactams. T cells appeared to mediate the effect: an anti-myelin basic protein T-cell line treated with cefuroxime or penicillin was more encephalitogenic in adoptive transfer experiments. The beta-lactam ampicillin, in contrast to cefuroxime and penicillin, did not enhance encephalomyelitis, but did inhibit the autoimmune diabetes developing spontaneously in nonobese diabetic mice. Gene expression analysis of human peripheral blood T cells showed that numerous genes associated with T helper 2 (Th2) and T regulatory (Treg) differentiation were down-regulated in T cells stimulated in the presence of cefuroxime; these genes were up-regulated in the presence of ampicillin. The T-cell protein that covalently bound beta-lactam antibiotics was found to be albumin. Human and rodent T cells expressed albumin mRNA and protein, and penicillin-modified albumin was taken up by rat T cells, leading to enhanced encephalitogenicity. Thus, beta-lactam antibiotics in wide clinical use have marked effects on T-cell behavior; beta-lactam antibiotics can function as immunomodulators, apparently through covalent binding to albumin.     

EBNA1BP2基因在肝癌形成过程中的表达及不同中医治法的调控作用

目的:探讨EBNA1BP2基因在肝癌形成过程中不同阶段的表达情况及不同中医治法对其在肝癌中表达的影响。方法:①以DEN诱发大鼠肝癌模型,分别观察造模4、8、16、20周后其肝脏组织病理形态学的改变以及EB-NA1BP2基因表达的差异。②应用基因芯片检测健脾益气、清热解毒、活血化瘀等常用中医治法对大鼠EBNA1BP2基因表达的影响。结果:①肝组织病理形态学观察结果表明,大鼠肝癌造模4、8周时肝组织主要表现为炎性病变,而到16周后呈现典型的增生病变,20周后已全部发展为肝细胞癌。②芯片结果显示,EBNA1BP2基因在DEN诱发大鼠肝癌形成过程中的表达量持续增加,至16周后形成表达高峰。③不同中医治法对EBNA1BP2基因在大鼠肝癌中具有不同程度的调控作用,其中健脾益气法下调作用较明显。结论:成功应用DEN诱发大鼠肝癌模型,EBNA1BP2基因在肝癌形成过程中表达持续增加,健脾益气法对其具有明显的下调作用。     

Growth hormone regulates leptin gene expression in bovine adipose tissue: correlation with adipose IGF-1 expression

Leptin, the product of the ob gene, is secreted from white adipocytes and regulates food intake and whole-body energy metabolism. In rodents and humans, leptin gene expression is under complex endocrine and metabolic control, and is strongly influenced by energy balance. Growth hormone (GH) has myriad effects on adipose tissue metabolism. The primary aim of this study was to determine the ability of GH to regulate leptin mRNA expression in bovine adipose tissue in vitro and in vivo. Incubation of subcutaneous adipose tissue explants for 24 h with GH alone had no effect on bovine leptin gene expression, whereas high concentrations of insulin or dexamethasone (DEX) potently stimulated bovine leptin mRNA abundance. GH, in combination with high concentrations of insulin, DEX, or both, attenuated the ability of insulin or DEX to stimulate leptin expression in vitro. These data indicate that GH can indirectly regulate leptin expression in vitro by altering the adipose tissue response to insulin or DEX. We extended these studies to examine the ability of GH to regulate leptin expression in vivo, using young castrate male cattle treated with no hormone (control) or GH (200 micrograms/kg body weight per day) for 3 days. GH increased plasma GH and insulin concentrations, but not those of cortisol or non-esterified fatty acid (NEFA) concentrations. GH treatment increased adipose tissue leptin and IGF-1 mRNA concentrations (n=9, P>0.001). In addition, leptin abundance was highly correlated with adipose tissue IGF-1 mRNA in GH-treated animals (P>0.001). The timing of GH-induced changes in leptin gene expression preceded measurable GH effects on adiposity.     

miRNA-21 regulates proatherosclerotic gene expression in macrophages

Background MicroRNAs(miRNANAs) are endogenous, small non-coding RNAs that negatively regulate gene expression in diverse cardiovascular diseases. However, the roles of miRNANAs in atherosclerogenesis needs to be elucidated. In the present study, the effect of miRNA-21 on pro-atherosclerotic genes expression was examined. Methods The pro-atherosclerotic genes including COX2, VCAM1, ICAM1, MCP1 and miRNA-21 were detected in ox-LDL-treated mouse macrophage RAW264.7 cells. ApoE knock-out(ApoEKO) mice were fed with high-fat diet for 16 weeks, and the abdominal aorta were fixed and used for miRNA-21 hybridization. Lentivirus-based vectors for enforced expression of miRNA-21 and antisense miRNA-21were prepared. The expression of proatherosclerotic genes was determined in the RAW264.7 cells with lentivirusmediated up-regulation of miRNA-21. Results COX2, VCAM1, ICAM1 and MCP1 could be up-regulated by ox-LDL treatment, and 50 μg / mL ox-LDL could significantly increase the expression of above four genes in ox-LDL EAW264.7 cells. miRNA-21 could also be markedly up-regulated in ox-LDL-induced RAW264.7cells. The result of miRNANA hybridization showed that miRNA-21 was strongly expressed in atherosclerotic plaques but not in normal aorta. Lentivirus-mediated over-expression of miRNA-21 could significantly enhance expressions of COX2, VCAM1, ICAM1 and MCP1 in RAW264.7 cells, which could be reversed by antisense miRNA-21 mediated by lentivirus vector. Conclusions miRNA-21 could be modulated by ox-LDL in macrophage RAW264.7 cells, and miRNA-21 could enhance COX2, VCAM1, ICAM1 and MCP1expressions in macrophages.     

Retroviral-mediated gene expression in human myelomonocytic cells: a comparison of hematopoietic cell promoters to viral promoters

Gene transfer into human hematopoietic stem cells with expression targeted to the maturing myelomonocytic progeny has applications for gene therapy of genetic diseases affecting granulocytes and macrophages. We hypothesized that promoters of myeloid-specific genes that are upregulated with myelomonocytic differentiation would also upregulate expression of an exogenous gene in a retroviral vector. Moloney murine leukemia virus (MoMuLV)-based retroviral vectors using promoters from hematopoietic genes (CD11b, CD18, and CD34) were compared with vectors with viral promoters (MoMuLV long terminal repeat [LTR], cytomegalovirus [CMV], and simian virus 40 [SV40]). Human glucocerebrosidase (GC) cDNA was the reporter gene. HL60 cells were transduced with these vectors and vector-derived GC activity was compared in undifferentiated HL-60 cells and the same cells differentiated into granulocytes using dimethyl sulfoxide or monocyte/macrophages using phorbol myristate acetate. In undifferentiated HL-60 cells, vector-derived GC activity was the highest when it was controlled by the MoMuLV LTR. In HL-60 cells differentiated into granulocytes, vector-derived GC activity transcribed from the CD11b, MoMuLV LTR, and CMV promoters was equivalent to 1.7, 1.5, and 1.5 times the normal endogenous GC activity, respectively, and 0.8, 2.0, and 3.6 times the normal GC activity, respectively, in those differentiated into macrophages. With granulocytic differentiation, the CD11b promoter showed maximal induction in GC activity (8-fold); with macrophage differentiation, the CD11b promoter showed a fourfold induction in GC expression. The CD11b promoter also generated significant levels of GC activity in the myelomonocytic progeny of transduced CD34+ cells. Expression from the CD11b promoter, unlike that from the CMV or the MoMuLV LTR promoters, was relatively myelomonocyte-specific, with minimal expression observed in Jurkat T cells or HeLa carcinoma cells. The induction of expression from the CD11b promoter with differentiation in HL-60 cells correlates with the developmental regulation of the CD11b gene. Retroviral vectors using the CD11b promoter have potential utility for gene therapy of disorders affecting the myelomonocytic lineage.     

Circ_RPPH1 regulates glioma cell malignancy by binding to miR-627-5p/miR-663a to induce SDC1 expression

Metabolic Brain Disease - Recent studies revealed the key role of circular RNA (circRNA) in glioma progression. However, the effect of circ_0000520, also named as circRNA ribonuclease P RNA...