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

Multiple myeloma (MM) has proven clinically susceptible to modulation of pathways of protein homeostasis. Blockade of proteasomal degradation of polyubiquitinated misfolded proteins by the proteasome inhibitor bortezomib (BTZ) achieves responses and prolongs survival in MM,but long-term treatment with BTZ leads to drug-resistant relapse in most patients. In a proof-of-concept study,we previously demonstrated that blocking aggresomal breakdown of polyubiquitinated misfolded proteins with the histone deacetylase 6 (HDAC6) inhibitor tubacin enhances BTZ-induced cytotoxicity in MM cells in vitro. However,these foundational studies were limited by the pharmacologic liabilities of tubacin as a chemical probe with only in vitro utility. Emerging from a focused library synthesis,a potent,selective,and bioavailable HDAC6 inhibitor,WT161,was created to study the mechanism of action of HDAC6 inhibition in MM alone and in combination with BTZ. WT161 in combination with BTZ triggers significant accumulation of polyubiquitinated proteins and cell stress,followed by caspase activation and apoptosis. More importantly,this combination treatment was effective in BTZ-resistant cells and in the presence of bone marrow stromal cells,which have been shown to mediate MM cell drug resistance. The activity of WT161 was confirmed in our human MM cell xenograft mouse model and established the framework for clinical trials of the combination treatment to improve patient outcomes in MM. View Publication

The prion protein (PrP) is highly conserved and ubiquitously expressed,suggesting that it plays an important physiological function. However,despite decades of investigation,this role remains elusive. Here,by using animal and cellular models,we unveil a key role of PrP in the DNA damage response. Exposure of neurons to a genotoxic stress activates PRNP transcription leading to an increased amount of PrP in the nucleus where it interacts with APE1,the major mammalian endonuclease essential for base excision repair,and stimulates its activity. Preventing the induction of PRNP results in accumulation of abasic sites in DNA and impairs cell survival after genotoxic treatment. Brains from Prnp(-/-) mice display a reduced APE1 activity and a defect in the repair of induced DNA damage in vivo. Thus,PrP is required to maintain genomic stability in response to genotoxic stresses. View Publication

Continued growth in the cell therapy industry and commercialization of cell therapies that successfully advance through clinical trials has led to increased awareness around the need for specialized and complex materials utilized in their manufacture. Ancillary materials (AMs) are components or reagents used during the manufacture of cell therapy products but are not intended to be part of the final products. Commonly,there are limitations in the availability of clinical-grade reagents used as AMs. Furthermore,AMs may affect the efficacy of the cell product and subsequent safety of the cell therapy for the patient. As such,AMs must be carefully selected and appropriately qualified during the cell therapy development process. However,the ongoing evolution of cell therapy research,limited number of clinical trials and registered cell therapy products results in the current absence of specific regulations governing the composition,compliance,and qualification of AMs often leads to confusion by suppliers and users in this field. Here we provide an overview and interpretation of the existing global framework surrounding AM use and investigate some common misunderstandings within the industry,with the aim of facilitating the appropriate selection and qualification of AMs. The key message we wish to emphasize is that in order to most effectively mitigate risk around cell therapy development and patient safety,users must work with their suppliers and regulators to qualify each AM to assess source,purity,identity,safety,and suitability in a given application. View Publication

The generation of human induced pluripotent stem cells (hiPSCs) requires the collection of donor tissue,but clinical circumstances in which the interests of patients have highest priority may compromise the quality and availability of cells that are eventually used for reprogramming. Here we compared (i) skin biopsies stored in standard physiological salt solution for up to two weeks (ii) blood outgrowth endothelial cells (BOECs) isolated from fresh peripheral blood and (iii) children's milk teeth lost during normal replacement for their ability to form somatic cell cultures suitable for reprogramming to hiPSCs. We derived all hiPSC lines using the same reprogramming method (a conditional (FLPe) polycistronic lentivirus) and under similar conditions (same batch of virus,fetal calf serum and feeder cells). Skin fibroblasts could be reprogrammed robustly even after long-term biopsy storage. Generation of hiPSCs from juvenile dental pulp cells gave similar high efficiencies,but that of BOECs was lower. In terms of invasiveness of biopsy sampling,biopsy storage and reprogramming efficiencies skin fibroblasts appeared best for the generation of hiPSCs,but where non-invasive procedures are required (e.g. for children and minors) dental pulp cells from milk teeth represent a valuable alternative. View Publication

Protein kinase Ciota (PKCiota) is an oncogene required for maintenance of the transformed phenotype of non-small cell lung cancer cells. However,the role of PKCiota in lung tumor development has not been investigated. To address this question,we established a mouse model in which oncogenic Kras(G12D) is activated by Cre-mediated recombination in the lung with or without simultaneous genetic loss of the mouse PKCiota gene,Prkci. Genetic loss of Prkci dramatically inhibits Kras-initiated hyperplasia and subsequent lung tumor formation in vivo. This effect correlates with a defect in the ability of Prkci-deficient bronchioalveolar stem cells to undergo Kras-mediated expansion and morphologic transformation in vitro and in vivo. Furthermore,the small molecule PKCiota inhibitor aurothiomalate inhibits Kras-mediated bronchioalveolar stem cell expansion and lung tumor growth in vivo. Thus,Prkci is required for oncogene-induced expansion and transformation of tumor-initiating lung stem cells. Furthermore,aurothiomalate is an effective antitumor agent that targets the tumor-initiating stem cell niche in vivo. These data have important implications for PKCiota as a therapeutic target and for the clinical use of aurothiomalate for lung cancer treatment. View Publication

We have studied the mechanism of A-769662,a new activator of AMP-activated protein kinase (AMPK). Unlike other pharmacological activators,it directly activates native rat AMPK by mimicking both effects of AMP,i.e. allosteric activation and inhibition of dephosphorylation. We found that it has no effect on the isolated alpha subunit kinase domain,with or without the associated autoinhibitory domain,or on interaction of glycogen with the beta subunit glycogen-binding domain. Although it mimics actions of AMP,it has no effect on binding of AMP to the isolated Bateman domains of the gamma subunit. The addition of A-769662 to mouse embryonic fibroblasts or primary mouse hepatocytes stimulates phosphorylation of acetyl-CoA carboxylase (ACC),effects that are completely abolished in AMPK-alpha1(-/-)alpha2(-/-) cells but not in TAK1(-/-) mouse embryonic fibroblasts. Phosphorylation of AMPK and ACC in response to A-769662 is also abolished in isolated mouse skeletal muscle lacking LKB1,a major upstream kinase for AMPK in this tissue. However,in HeLa cells,which lack LKB1 but express the alternate upstream kinase calmodulin-dependent protein kinase kinase-beta,phosphorylation of AMPK and ACC in response to A-769662 still occurs. These results show that in intact cells,the effects of A-769662 are independent of the upstream kinase utilized. We propose that this direct and specific AMPK activator will be a valuable experimental tool to understand the physiological roles of AMPK. View Publication

Cardiomyocytes (CM) derived from human embryonic stem cells (hESC) are used for cardio-toxicity evaluation and tested in many preclinical trials for their potential use in regenerative therapeutics. As more efficient CM differentiation protocols are developed,reliable automated platforms for characterization and detection are needed. An automated time-resolved video analysis and management system (TVAMS) has been developed for the evaluation of hESC differentiation to CM. The system was used for monitoring the kinetics of embryoid bodies (EB) generation (numbers and size) and differentiation into beating EBs (percentage beating area and beating EB count) in two differentiation protocols. We show that the percentage beating areas of EBs (from total area of the EBs) is a more sensitive and better predictor of CM differentiation efficiency than percentage of beating EBs (from total EBs) as the percentage beating areas of EBs correlates with cardiac troponin-T and myosin heavy chain expression levels. TVAMS can also be used to evaluate the effect of drugs and inhibitors (e.g. isoproterenol and ZD7288) on CM beating frequency. TVAMS can reliably replace the commonly practiced,time consuming,manual counting of total and beating EBs during CM differentiation. TVAMS is a high-throughput non-invasive video imaging platform that can be applied for the development of new CM differentiation protocols,as well as a tool to conduct CM toxicology assays. View Publication

Efficient allocation of deceased donor organs depends upon effective prediction of immunologic compatibility based on donor HLA genotype and recipient alloantibody profile,referred to as virtual crossmatching (VCXM). VCXM has demonstrated utility in predicting compatibility,though there is reduced efficacy for patients highly sensitized against allogeneic HLA antigens. The recently revised deceased donor kidney allocation system (KAS) has increased transplantation for this group,but with an increased burden for histocompatibility testing and organ sharing. Given the limitations of VCXM,we hypothesized that increased organ offers for highly-sensitized patients could result in a concomitant increase in offers rejected due to unexpectedly positive crossmatch. Review of 645 crossmatches performed for deceased donor kidney transplantation at our center did not reveal a significant increase in positive crossmatches following KAS implementation. Positive crossmatches not predicted by VCXM were concentrated among highly-sensitized patients. Root cause analysis of VCXM failures identified technical limitations of anti-HLA antibody testing as the most significant contributor to VCXM error. Contributions of technical limitations including additive/synergistic antibody effects,prozone phenomenon,and antigens not represented in standard testing panels,were evaluated by retrospective testing. These data provide insight into the limitations of VCXM,particularly those affecting allocation of kidneys to highly-sensitized patients. View Publication

The administration of antiretroviral therapy (ART) leads to a rapid reduction in plasma viral load in HIV-1 seropositive subjects. However,when ART is suspended,the virus rebounds due to the presence of a latent viral reservoir. Several techniques have been developed to characterize this latent viral reservoir. Of the various assay formats available presently,the Tat/Rev induced limiting dilution assay (TILDA) offers the most robust and technically simple assay strategy. The TILDA formats reported thus far are limited by being selective to one or a few HIV-1 genetic subtypes,thus,restricting them from a broader level application. The novel TILDA,labelled as U-TILDA ('U' for universal),can detect all the major genetic subtypes of HIV-1 unbiasedly,and with comparable sensitivity of detection. U-TILDA is well suited to characterize the latent reservoirs of HIV-1 and aid in the formulation of cure strategies. Graphical abstract. View Publication

Monoclonal antibodies are at the vanguard of the most promising cancer treatments. Whereas traditional therapeutic antibodies have been limited to extracellular antigens,T cell receptor mimic (TCRm) antibodies can target intracellular antigens presented by cell surface major histocompatibility complex (MHC) proteins. TCRm antibodies can therefore target a repertoire of otherwise undruggable cancer antigens. However,the consequences of off-target peptide/MHC recognition with engineered T cell therapies are severe,and thus there are significant safety concerns with TCRm antibodies. Here we explored the specificity and safety profile of a new TCRm-based T cell therapy for hepatocellular carcinoma (HCC),a solid tumor for which no effective treatment exists. We targeted an alpha-fetoprotein peptide presented by HLA-A*02 with a highly specific TCRm,which crystallographic structural analysis showed binds directly over the HLA protein and interfaces with the full length of the peptide. We fused the TCRm to the ? and ? subunits of a TCR,producing a signaling AbTCR construct. This was combined with an scFv/CD28 co-stimulatory molecule targeting glypican-3 for increased efficacy towards tumor cells. This AbTC + co-stimulatory T cell therapy showed potent activity against AFP-positive cancer cell lines in vitro and an in an in vivo model and undetectable activity against AFP-negative cells. In an in-human safety assessment,no significant adverse events or cytokine release syndrome were observed and evidence of efficacy was seen. Remarkably,one patient with metastatic HCC achieved a complete remission after nine months and ultimately qualified for a liver transplant. View Publication

The HOX family of homeobox genes plays an important role in normal and malignant hematopoiesis. Dysregulated HOX gene expression profoundly effects the proliferation and differentiation of hematopoietic stem cells (HSCs) and committed progenitors,and aberrant activation of HOX genes is a common event in human myeloid leukemia. HOXB6 is frequently overexpressed in human acute myeloid leukemia (AML). To gain further insight into the role of HOXB6 in hematopoiesis,we overexpressed HOXB6 in murine bone marrow using retrovirus-mediated gene transfer. We also explored structure-function relationships using mutant HOXB6 proteins unable to bind to DNA or a key HOX-binding partner,pre-B-cell leukemia transcription factor-1 (PBX1). Additionally,we investigated the potential cooperative interaction with myeloid ecotropic viral integration site 1 homolog (MEIS1). In vivo,HOXB6 expanded HSCs and myeloid precursors while inhibiting erythropoiesis and lymphopoiesis. Overexpression of HOXB6 resulted in AML with a median latency of 223 days. Coexpression of MEIS1 dramatically shortened the onset of AML. Cytogenetic analysis of a subset of HOXB6-induced AMLs revealed recurrent deletions of chromosome bands 2D-E4,a region frequently deleted in HOXA9-induced AMLs. In vitro,HOXB6 immortalized a factor-dependent myelomonocytic precursor capable of granulocytic and monocytic differentiation. These biologic effects of HOXB6 were largely dependent on DNA binding but independent of direct interaction with PBX1. View Publication