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Kawasaki disease (KD) is an acute vasculitis of infants and young children,preferentially affecting the coronary arteries. Intravenous infusion of high dose Ig (IVIG) effectively reduces systemic inflammation and prevents coronary artery lesions in KD. To investigate the mechanisms underlying the therapeutic effects of IVIG,we examined gene expression profiles of PBMC and purified monocytes obtained from acute patients before and after IVIG therapy. The results suggest that IVIG suppresses activated monocytes and macrophages by altering various functional aspects of the genes of KD patients. Among the 18 commonly decreased transcripts in both PBMC and purified monocytes,we selected six genes,FCGR1A,FCGR3A,CCR2,ADM,S100A9,and S100A12,and confirmed the microarray results by real-time RT-PCR. Moreover,the expressions of FcgammaRI and FcgammaRIII on monocytes were reduced after IVIG. Plasma S100A8/A9 heterocomplex,but not S100A9,levels were elevated in patients with acute KD compared with those in febrile controls. Furthermore,S100A8/A9 was rapidly down-regulated in response to IVIG therapy. Persistent elevation of S100A8/A9 after IVIG was found in patients who later developed coronary aneurysms. These results indicate that the effects of IVIG in KD may be mediated by suppression of an array of immune activation genes in monocytes,including those activating FcgammaRs and the S100A8/A9 heterocomplex. View Publication

Chalcones are precursor compounds for flavonoid synthesis in plants,and they can also be synthesized in laboratory. Previous study has documented some of the pharmacological applications of these compounds. Estrogen has long been associated with the initiation and promotion of breast cancer. Inhibiting estrogen synthesis can be effective in the prevention and treatment of the disease. Since most breast cancers received estrogen supplied from local tissues,we employed a breast cancer cell line expressing aromatase to screen for the inhibitory potentials of five hydroxychalcones,i.e. 2-hydroxychalcone,2'-hydroxychalcone,4-hydroxychalcone,4,2',4'-trihydroxy-chalcone (isoquiritigenin),3,4,2',4'-tetrahydroxychalcone (butein). In the preliminary results,butein was found to be the strongest inhibitor among the tested compounds,and its IC(50) value was 3.75 microM. Subsequent enzyme kinetic study revealed that butein acted on aromatase with a mixed type of inhibition and the K(i) value was determined to be 0.32 microM. Cell proliferation assay indicated that the cell number increased by 10 nM-testosterone treatment was significantly reduced by 5 microM butein,and the administration of flutamide could not reverse the effect. The present study illustrated that butein was an aromatase inhibitor and a potential natural alternative for the chemoprevention or therapy of breast cancer. View Publication

Imatinib,a Bcr-Abl tyrosine kinase inhibitor,is a highly effective therapy for patients with chronic myelogenous leukemia (CML). Despite durable responses in most chronic phase patients,relapses have been observed and are much more prevalent in patients with advanced disease. The most common mechanism of acquired imatinib resistance has been traced to Bcr-Abl kinase domain mutations with decreased imatinib sensitivity. Thus,alternate Bcr-Abl kinase inhibitors that have activity against imatinib-resistant mutants would be useful for patients who relapse on imatinib therapy. Two such Bcr-Abl inhibitors are currently being evaluated in clinical trials: the improved potency,selective Abl inhibitor AMN107 and the highly potent dual Src/Abl inhibitor BMS-354825. In the current article,we compared imatinib,AMN107,and BMS-354825 in cellular and biochemical assays against a panel of 16 kinase domain mutants representing textgreater90% of clinical isolates. We report that AMN107 and BMS-354825 are 20-fold and 325-fold more potent than imatinib against cells expressing wild-type Bcr-Abl and that similar improvements are maintained for all imatinib-resistant mutants tested,with the exception of T315I. Thus,both inhibitors hold promise for treating imatinib-refractory CML. View Publication

OBJECTIVE: To compare the suppressive effect of mesenchymal stem cells (MSC),derived from normal individuals or severe aplastic anemia patients (SAA),on T-cell activation. PATIENTS AND METHODS: We studied bone marrow MSC from 19 healthy donors and 23 SAA patients in different phases of the disease: at diagnosis (n = 3),following immunosuppressive therapy (IS) (n = 16),or after a bone marrow transplant (BMT) (n = 4). MSC were tested for T-cell suppression in the following assays: mixed lymphocyte reaction (MLR),phytohemaglutinin (PHA)-primed cultures,activation surface markers,gamma-IFN production,hematopoietic colony formation (CFC),production of cyclic ADP-ribose (cADPR). RESULTS: The abnormalities of SAA MSC included: 1) significantly lower suppression of T-cell proliferation induced by alloantigens (p = 0.009) or PHA (p = 0.006); 2) impaired capacity to suppress CD38 expression on PHA-primed T cells (p = 0.001); 3) impaired ability to suppress gamma-IFN production in PHA cultures,resulting in an 11-fold higher gamma-IFN concentration; 4) no preventive effect on T cell-mediated inhibition of CFC; and 5) significantly reduced (p = 0.009) production of cADPR,a universal calcium mobilizer. MSC-mediated suppression of PHA-induced T-cell proliferation was restored to control levels in 3 of 4 patients post-BMT. CONCLUSION: The ability of MSC to downregulate T-cell priming,proliferation,and cytokine release is deficient in patients with SAA,persists indefinitely after immunosuppressive therapy,but seems to be restored after BMT. Whether these abnormalities are relevant to the pathogenesis of aplastic anemia remains to be determined. View Publication

A series of 30 N10-substituted phenoxazines were synthesized and screened as potential inhibitors of Akt. In cellular assays at 5 mum,17 compounds inhibited insulin-like growth factor 1 (IGF-I)-stimulated phosphorylation of Akt (Ser-473) by at least 50% but did not inhibit IGF-I-stimulated phosphorylation of Erk-1/2 (Thr-202/Tyr-204). Substitutions at the 2-position (Cl or CF3) did not alter inhibitory activity,whereas N10-substitutions with derivatives having acetyl (20B) or morpholino (12B) side chain lost activity compared with propyl or butyl substituents (7B and 14B). Inhibition of Akt phosphorylation was associated with the inhibition of IGF-I stimulation of the mammalian target of rapamycin phosphorylation (Ser-2448 and Ser-2481),phosphorylation of p70 S6 kinase (Thr-389),and ribosomal protein S6 (Ser-235/236) in Rh1,Rh18,and Rh30 cell lines. The two most potent compounds 10-[4'-(N-diethylamino)butyl]-2-chlorophenoxazine (10B) and 10-[4'-[(beta-hydroxyethyl)piperazino]butyl]-2-chlorophenoxazine (15B) (in vitro,IC50 approximately 1-2 microM) were studied further. Inhibition of Akt phosphorylation correlated with inhibition of its kinase activity as determined in vitro after immunoprecipitation. Akt inhibitory phenoxazines did not inhibit the activity of recombinant phosphatidylinositol 3'-kinase,PDK1,or SGK1 but potently inhibited the kinase activity of recombinant Akt and Akt deltaPH,a mutant lacking the pleckstrin homology domain. Akt inhibitory phenoxazines blocked IGF-I-stimulated nuclear translocation of Akt in Rh1 cells and suppressed growth of Rh1,Rh18,and Rh30 cells (IC50 2-5 microM),whereas inactive" derivatives were textgreater or = 10-fold less potent inhibitors of cell growth. In contrast to rapamycin analogs� View Publication

The hematopoietic stem cell (HSC) gives rise to all mature,terminally differentiated cells of the blood. Here we show that calmodulin-dependent protein kinase IV (CaMKIV) is present in c-Kit+ ScaI+ Lin(-/low) hematopoietic progenitor cells (KLS cells) and that its absence results in hematopoietic failure,characterized by a diminished KLS cell population and by an inability of these cells to reconstitute blood cells upon serial transplantation. KLS cell failure in the absence of CaMKIV is correlated with increased apoptosis and proliferation of these cells in vivo and in vitro. In turn,these cell biological defects are correlated with decreases in CREB-serine 133 phosphorylation as well as in CREB-binding protein (CBP) and Bcl-2 levels. Re-expression of CaMKIV in Camk4-/- KLS cells results in the rescue of the proliferation defects in vitro as well as in the restoration of CBP and Bcl-2 to wild type levels. These studies show that CaMKIV is a regulator of HSC homeostasis and suggest that its effects may be in part mediated via regulation of CBP and Bcl-2. View Publication

DNA methylation regulates gene expression in normal and malignant cells. The possibility to reactivate epigenetically silenced genes has generated considerable interest in the development of DNA methyltransferase inhibitors. Here,we provide a detailed characterization of RG108,a novel small molecule that effectively blocked DNA methyltransferases in vitro and did not cause covalent enzyme trapping in human cell lines. Incubation of cells with low micromolar concentrations of the compound resulted in significant demethylation of genomic DNA without any detectable toxicity. Intriguingly,RG108 caused demethylation and reactivation of tumor suppressor genes,but it did not affect the methylation of centromeric satellite sequences. These results establish RG108 as a DNA methyltransferase inhibitor with fundamentally novel characteristics that will be particularly useful for the experimental modulation of epigenetic gene regulation. View Publication

To realize the full potential of targeted protein kinase inhibitors for the treatment of cancer,it is important to address the emergence of drug resistance in treated patients. Mutant forms of BCR-ABL,KIT,and the EGF receptor (EGFR) have been found that confer resistance to the drugs imatinib,gefitinib,and erlotinib. The mutations weaken or prevent drug binding,and interestingly,one of the most common sites of mutation in all three kinases is a highly conserved gatekeeper" threonine residue near the kinase active site. We have identified existing clinical compounds that bind and inhibit drug-resistant mutant variants of ABL� View Publication

Several recent reports suggest that there is far more plasticity that previously believed in the developmental potential of bone-marrow-derived cells (BMCs) that can be induced by extracellular developmental signals of other lineages whose nature is still largely unknown. In this study,we demonstrate that bone-marrow-derived mesenchymal stem cells (MSCs) co-cultured with mouse proliferating or fixed (by paraformaldehyde or methanol) neural stem cells (NSCs) generate neural stem cell-like cells with a higher expression of Sox-2 and nestin when grown in NS-A medium supplemented with N2,NSC conditioned medium (NSCcm) and bFGF. These neurally induced MSCs eventually differentiate into beta-III-tubulin and GFAP expressing cells with neuronal and glial morphology when grown an additional week in Neurobasal/B27 without bFGF. We conclude that juxtacrine interaction between NSCs and MSCs combined with soluble factors released from NSCs are important for generation of neural-like cells from bone-marrow-derived adherent MSCs. View Publication

The induction of senescence-like growth arrest has emerged as a putative contributor to the anticancer effects of chemotherapeutic agents. Clinical trials are underway to evaluate the efficacy of inhibitors for class I and II histone deacetylases to treat malignancies. However,a potential antiproliferative effect of inhibitor for Sirt1,which is an NAD(+)-dependent deacetylase and belongs to class III histone deacetylases,has not yet been explored. Here,we show that Sirt1 inhibitor,Sirtinol,induced senescence-like growth arrest characterized by induction of senescence-associated beta-galactosidase activity and increased expression of plasminogen activator inhibitor 1 in human breast cancer MCF-7 cells and lung cancer H1299 cells. Sirtinol-induced senescence-like growth arrest was accompanied by impaired activation of mitogen-activated protein kinase (MAPK) pathways,namely,extracellular-regulated protein kinase,c-jun N-terminal kinase and p38 MAPK,in response to epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I). Active Ras was reduced in Sirtinol-treated senescent cells compared with untreated cells. However,tyrosine phosphorylation of the receptors for EGF and IGF-I and Akt/PKB activation were unaltered by Sirtinol treatment. These results suggest that inhibitors for Sirt1 may have anticancer potential,and that impaired activation of Ras-MAPK pathway might take part in a senescence-like growth arrest program induced by Sirtinol. View Publication

The beta-globin locus control region (LCR) is a large DNA element that is required for high-level expression of beta-like globin genes from the endogenous mouse locus or in transgenic mice carrying the human beta-globin locus. The LCR encompasses 6 DNaseI hypersensitive sites (HSs) that bind transcription factors. These HSs each contain a core of a few hundred base pairs (bp) that has most of the functional activity and exhibits high interspecies sequence homology. Adjoining the cores are 500- to 1000-bp flanks" with weaker functional activity and lower interspecies homology. Studies of human beta-globin transgenes and of the endogenous murine locus show that deletion of an entire HS (core plus flanks) moderately suppresses expression. However� View Publication

OBJECTIVES: The goal of this study was to modify mesenchymal stem cells (MSCs) cells with a hypoxia-regulated heme oxygenase-1 (HO-1) plasmid to enhance the survival of MSCs in acute myocardial infarction (MI) heart. BACKGROUND: Although stem cells are being tested clinically for cardiac repair,graft cells die in the ischemic heart because of the effects of hypoxia/reoxygenation,inflammatory cytokines,and proapoptotic factors. Heme oxygenase-1 is a key component in inhibiting most of these factors. METHODS: Mesenchymal stem cells from bone marrow were transfected with either HO-1 or LacZ plasmids. Cell apoptosis was assayed in vitro after hypoxia-reoxygen treatment. In vivo,1 x 10(6) of male MSC(HO-1),MSC(LacZ),MSCs,or medium was injected into mouse hearts 1 h after MI (n = 16/group). Cell survival was assessed in a gender-mismatched transplantation model. Apoptosis,left ventricular remodeling,and cardiac function were tested in a gender-matched model. RESULTS: In the ischemic myocardium,the MSC(HO-1) group had greater expression of HO-1 and a 2-fold reduction in the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate in situ nick end labeling-positive cells compared with the MSC(LacZ) group. At seven days after implantation,the survival MSC(HO-1) was five-fold greater than the MSC(LacZ) group; MSC(HO-1) also attenuated left ventricular remodeling and enhanced the functional recovery of infarcted hearts two weeks after MI. CONCLUSIONS: A hypoxia-regulated HO-1 vector modification of MSCs enhances the tolerance of engrafted MSCs to hypoxia-reoxygen injury in vitro and improves their viability in ischemic hearts. This demonstration is the first showing that a physiologically inducible vector expressing of HO-1 genes improves the survival of stem cells in myocardial ischemia. View Publication