搜索结果: 'methocult media formulations for human hematopoietic cells serum containing'

HIV infection leads to a state of chronic immune activation and progressive deterioration in immune function,manifested most recognizably by the progressive depletion of CD4+ T cells. A substantial percentage of natural killer (NK) cells from patients with HIV infection are activated and express the natural cytotoxicity receptor (NCR) NKp44. Here we show that a cellular ligand for NKp44 (NKp44L) is expressed during HIV-1 infection and is correlated with both the progression of CD4+ T cell depletion and the increase of viral load. CD4+ T cells expressing this ligand are highly sensitive to the NK lysis activity mediated by NKp44+ NK cells. The expression of NKp44L is induced by the linear motif NH2-SWSNKS-COOH of the HIV-1 envelope gp41 protein. This highly conserved motif appears critical to the sharp increase in NK lysis of CD4+ T cells from HIV-infected patients. These studies strongly suggest that induction of NKp44L plays a key role in the lysis of CD4+ T cells by activated NK cells in HIV infection and consequently provide a framework for considering how HIV-1 may use NK cell immune surveillance to trigger CD4+ T cells. Understanding this mechanism may help to develop future therapeutic strategies and vaccines against HIV-1 infection. View Publication

Current treatment options for advanced and hormone refractory prostate cancer are limited and responses to commonly used androgen pathway inhibitors are often unsatisfactory. Our recent results indicated that sodium ionophore monensin is one of the most potent and cancer-specific inhibitors in a systematic sensitivity testing of most known drugs and drug-like molecules in a panel of prostate cancer cell models. Because monensin has been extensively used in veterinary applications to build muscle mass in cattle,the link to prostate cancer and androgen signaling was particularly interesting. Here,we showed that monensin effects at nanomolar concentrations are linked to induction of apoptosis and potent reduction of androgen receptor mRNA and protein in prostate cancer cells. Monensin also elevated intracellular oxidative stress in prostate cancer cells as evidenced by increased generation of intracellular reactive oxygen species and by induction of a transcriptional profile characteristic of an oxidative stress response. Importantly,the antiproliferative effects of monensin were potentiated by combinatorial treatment with the antiandrogens and antagonized by antioxidant vitamin C. Taken together,our results suggest monensin as a potential well-tolerated,in vivo compatible drug with strong proapoptotic effects in prostate cancer cells,and synergistic effects with antiandrogens. Moreover,our data suggest a general strategy by which the effects of antiandrogens could be enhanced by combinatorial administration with agents that increase oxidative stress in prostate cancer cells. View Publication

Systemic mastocytosis (SM) is a myeloid neoplasm involving mast cells (MCs) and their progenitors. In most cases,neoplastic cells display the D816V-mutated variant of KIT. KIT D816V exhibits constitutive tyrosine kinase (TK) activity and has been implicated in increased survival and growth of neoplastic MCs. Recent data suggest that the proapoptotic BH3-only death regulator Bim plays a role as a tumor suppressor in various myeloid neoplasms. We found that KIT D816V suppresses expression of Bim in Ba/F3 cells. The KIT D816-induced down-regulation of Bim was rescued by the KIT-targeting drug PKC412/midostaurin. Both PKC412 and the proteasome-inhibitor bortezomib were found to decrease growth and promote expression of Bim in MC leukemia cell lines HMC-1.1 (D816V negative) and HMC-1.2 (D816V positive). Both drugs were also found to counteract growth of primary neoplastic MCs. Furthermore,midostaurin was found to cooperate with bortezomib and with the BH3-mimetic obatoclax in producing growth inhibition in both HMC-1 subclones. Finally,a Bim-specific siRNA was found to rescue HMC-1 cells from PKC412-induced cell death. Our data show that KIT D816V suppresses expression of proapoptotic Bim in neoplastic MCs. Targeting of Bcl-2 family members by drugs promoting Bim (re)-expression,or by BH3-mimetics such as obatoclax,may be an attractive therapy concept in SM. View Publication

Deletions and/or mutations of p53 are relatively rare and late events in the natural history of B-cell chronic lymphocytic leukemia (B-CLL). However,it is unknown whether p53 signaling is functional in B-CLL and if targeted nongenotoxic activation of the p53 pathway by using nutlin-3,a small molecule inhibitor of the p53/MDM2 interaction,is sufficient to kill B-CLL cells. In vitro treatment with nutlin-3 induced a significant cytotoxicity on primary CD19(+) B-CLL cells,but not on normal CD19(+) B lymphocytes,peripheral-blood mononuclear cells,or bone marrow hematopoietic progenitors. Among 29 B-CLL samples examined,only one was resistant to nutlin-3-mediated cytotoxicity. The induction of p53 by nutlin-3 in B-CLL samples was accompanied by alterations of the mitochondrial potential and activation of the caspase-dependent apoptotic pathway. Among several genes related to the p53 pathway,nutlin-3 up-regulated the steady-state mRNA levels of PCNA,CDKN1A/p21,GDF15,TNFRSF10B/TRAIL-R2,TP53I3/PIG3,and GADD45. This profile of gene activation showed a partial overlapping with that induced by the genotoxic drug fludarabine. Moreover,nutlin-3 synergized with both fludarabine and chlorambucil in inducing B-CLL apoptosis. Our data strongly suggest that nutlin-3 should be further investigated for clinical applications in the treatment of B-CLL. View Publication

The importance of cancer metabolism has been appreciated for many years,but the intricacies of how metabolic pathways interconnect with oncogenic signaling are not fully understood. With a clear understanding of how metabolism contributes to tumorigenesis,we will be better able to integrate the targeting of these fundamental biochemical pathways into patient care. The mevalonate (MVA) pathway,paced by its rate-limiting enzyme,hydroxymethylglutaryl coenzyme A reductase (HMGCR),is required for the generation of several fundamental end-products including cholesterol and isoprenoids. Despite years of extensive research from the perspective of cardiovascular disease,the contribution of a dysregulated MVA pathway to human cancer remains largely unexplored. We address this issue directly by showing that dysregulation of the MVA pathway,achieved by ectopic expression of either full-length HMGCR or its novel splice variant,promotes transformation. Ectopic HMGCR accentuates growth of transformed and nontransformed cells under anchorage-independent conditions or as xenografts in immunocompromised mice and,importantly,cooperates with RAS to drive the transformation of primary mouse embryonic fibroblasts cells. We further explore whether the MVA pathway may play a role in the etiology of human cancers and show that high mRNA levels of HMGCR and additional MVA pathway genes correlate with poor prognosis in a meta-analysis of six microarray datasets of primary breast cancer. Taken together,our results suggest that HMGCR is a candidate metabolic oncogene and provide a molecular rationale for further exploring the statin family of HMGCR inhibitors as anticancer agents. View Publication

Overcoming imatinib mesylate (IM) resistance and disease persistence in patients with chronic myeloid leukemia (CML) is of considerable importance to the issue of potential cure. Here we asked whether autocrine signaling contributes to survival of BCR/ABL+ cells in the presence of IM and nilotinib (NI; AMN107),a novel,more selective Abl inhibitor. Conditioned media (CM) of IM-resistant LAMA84 cell clones (R-CM) was found to substantially protect IM-naive LAMA cells and primary CML progenitors from IM- or NI-induced cell death. This was due to an increased secretion of the granulocyte-macrophage colony-stimulating factor (GM-CSF),which was identified as the causative factor mediating IM resistance in R-CM. GM-CSF elicited IM and NI drug resistance via a BCR/ABL-independent activation of the janus kinases 2 (JAK-2)/signal transducer and activator of transcription 5 (STAT-5) signaling pathway in GM-CSF receptor alpha receptor (CD116)-expressing cells,including primary CD34+/CD116+ GM progenitors (GMPs). Elevated mRNA and protein levels of GM-CSF were detected in IM-resistant patient samples,suggesting a contribution of GM-CSF secretion for IM and NI resistance in vivo. Importantly,inhibition of JAK-2 with AG490 abrogated GM-CSF-mediated STAT-5 phosphorylation and NI resistance in vitro. Together,adaptive autocrine secretion of GM-CSF mediates BCR/ABL-independent IM and NI resistance via activation of the antiapoptotic JAK-2/STAT-5 pathway. Inhibition of JAK-2 overcomes GM-CSF-induced IM and NI progenitor cell resistance,providing a rationale for the application of JAK-2 inhibitors to eradicate residual disease in CML. View Publication

Multiple myeloma is characterized by increased osteoclast activity that results in bone destruction and lytic lesions. With the prolonged overall patient survival achieved by new treatment modalities,additional drugs are required to inhibit bone destruction. We focused on a novel and more potent structural analog of the nonsteroidal anti-inflammatory drug etodolac,known as SDX-308,and its effects on osteoclastogenesis and multiple myeloma cells. SDX-101 is another structural analog of etodolac that is already used in clinical trials for the treatment of B-cell chronic lymphocytic leukemia (B-CLL). Compared with SDX-101,a 10-fold lower concentration of SDX-308 induced potent (60%-80%) inhibition of osteoclast formation,and a 10- to 100-fold lower concentration inhibited multiple myeloma cell proliferation. Bone resorption was completely inhibited by SDX-308,as determined in dentin-based bone resorption assays. SDX-308 decreased constitutive and RANKL-stimulated NF-kappaB activation and osteoclast formation in an osteoclast cellular model,RAW 264.7. SDX-308 effectively suppressed TNF-alpha-induced IKK-gamma and IkappaB-alpha phosphorylation and degradation and subsequent NF-kappaB activation in human multiple myeloma cells. These results indicate that SDX-308 effectively inhibits multiple myeloma cell proliferation and osteoclast activity,potentially by controlling NF-kappaB activation signaling. We propose that SDX-308 is a promising therapeutic candidate to inhibit multiple myeloma growth and osteoclast activity and that it should receive attention for further study. View Publication

Protein geranylgeranyltransferase type I (GGTase-I) is responsible for the posttranslational lipidation of CAAX proteins such as RHOA,RAC1,and cell division cycle 42 (CDC42). Inhibition of GGTase-I has been suggested as a strategy to treat cancer and a host of other diseases. Although several GGTase-I inhibitors (GGTIs) have been synthesized,they have very different properties,and the effects of GGTIs and GGTase-I deficiency are unclear. One concern is that inhibiting GGTase-I might lead to severe toxicity. In this study,we determined the effects of GGTase-I deficiency on cell viability and K-RAS-induced cancer development in mice. Inactivating the gene for the critical beta subunit of GGTase-I eliminated GGTase-I activity,disrupted the actin cytoskeleton,reduced cell migration,and blocked the proliferation of fibroblasts expressing oncogenic K-RAS. Moreover,the absence of GGTase-I activity reduced lung tumor formation,eliminated myeloproliferative phenotypes,and increased survival of mice in which expression of oncogenic K-RAS was switched on in lung cells and myeloid cells. Interestingly,several cell types remained viable in the absence of GGTase-I,and myelopoiesis appeared to function normally. These findings suggest that inhibiting GGTase-I may be a useful strategy to treat K-RAS-induced malignancies. View Publication

OBJECTIVE: In this study,the alternative splicing product of vasohibin 1 (VASH1B) was analyzed in direct comparison to the major isoform (VASH1A) for antiangiogenic effects on endothelial colony forming cells (ECFCs) from peripheral blood and on human umbilical vein endothelial cells (HUVECs). METHODS AND RESULTS: Expression studies in primary human endothelial cells revealed that both vasohibin proteins,hVASH1A and hVASH1B,localized in the nucleus and cytoplasm. Adenoviruses carrying the cDNA for VASH1A/B and purified recombinant proteins were used to study the function of both molecules in ECFCs and HUVECs. Recombinant VASH1A protein did not inhibit cell proliferation,tube formation,or vessel growth in vivo in the chick chorioallantoic membrane (CAM) assay,but promoted endothelial cell migration in vitro. The VASH1B protein had an inhibitory effect on cell proliferation,migration,tube formation,and inhibited blood vessel formation in the CAM assay. Adenoviral overexpression of VASH1B,but not of VASH1A,resulted in inhibition of endothelial cell growth,migration,and capillary formation. Interestingly,overexpression of VASH1A and B induced apoptosis in proliferating human fibroblasts,but did not affect cell growth of keratinocytes. CONCLUSIONS: Our data point out that alternative splicing of the VASH1 pre-mRNA transcript generates a potent antiangiogenic protein. View Publication

BACKGROUND We previously showed that small interfering RNAs (siRNAs) targeting the Zaire Ebola virus (ZEBOV) RNA polymerase L protein formulated in stable nucleic acid-lipid particles (SNALPs) completely protected guineapigs when administered shortly after a lethal ZEBOV challenge. Although rodent models of ZEBOV infection are useful for screening prospective countermeasures,they are frequently not useful for prediction of efficacy in the more stringent non-human primate models. We therefore assessed the efficacy of modified non-immunostimulatory siRNAs in a uniformly lethal non-human primate model of ZEBOV haemorrhagic fever. METHODS A combination of modified siRNAs targeting the ZEBOV L polymerase (EK-1 mod),viral protein (VP) 24 (VP24-1160 mod),and VP35 (VP35-855 mod) were formulated in SNALPs. A group of macaques (n=3) was given these pooled anti-ZEBOV siRNAs (2 mg/kg per dose,bolus intravenous infusion) after 30 min,and on days 1,3,and 5 after challenge with ZEBOV. A second group of macaques (n=4) was given the pooled anti-ZEBOV siRNAs after 30 min,and on days 1,2,3,4,5,and 6 after challenge with ZEBOV. FINDINGS Two (66%) of three rhesus monkeys given four postexposure treatments of the pooled anti-ZEBOV siRNAs were protected from lethal ZEBOV infection,whereas all macaques given seven postexposure treatments were protected. The treatment regimen in the second study was well tolerated with minor changes in liver enzymes that might have been related to viral infection. INTERPRETATION This complete postexposure protection against ZEBOV in non-human primates provides a model for the treatment of ZEBOV-induced haemorrhagic fever. These data show the potential of RNA interference as an effective postexposure treatment strategy for people infected with Ebola virus,and suggest that this strategy might also be useful for treatment of other emerging viral infections. FUNDING Defense Threat Reduction Agency. View Publication