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

Recurrent/metastatic head and neck cancer remains a devastating disease with insufficient treatment options. We investigated the MET receptor tyrosine kinase as a novel target for the treatment of head and neck squamous cell carcinoma (HNSCC). MET/phosphorylated MET and HGF expression was analyzed in 121 tissues (HNSCC/normal) by immunohistochemistry,and in 20 HNSCC cell lines by immunoblotting. The effects of MET inhibition using small interfering RNA/two small-molecule inhibitors (SU11274/PF-2341066) on signaling,migration,viability,and angiogenesis were determined. The complete MET gene was sequenced in 66 head and neck cancer tissue samples and eight cell lines. MET gene copy number was determined in 14 cell lines and 23 tumor tissues. Drug combinations of SU11274 with cisplatin or erlotinib were tested in SCC35/HN5 cell lines. Eighty-four percent of the HNSCC samples showed MET overexpression,whereas 18 of 20 HNSCC cell lines (90%) expressed MET. HGF overexpression was present in 45% of HNSCC. MET inhibition with SU11274/PF-2341066 abrogated MET signaling,cell viability,motility/migration in vitro,and tumor angiogenesis in vivo. Mutational analysis of 66 tumor tissues and 8 cell lines identified novel mutations in the semaphorin (T230M/E168D/N375S),juxtamembrane (T1010I/R988C),and tyrosine kinase (T1275I/V1333I) domains (incidence: 13.5%). Increased MET gene copy number was present with textgreater10 copies in 3 of 23 (13%) tumor tissues. A greater-than-additive inhibition of cell growth was observed when combining a MET inhibitor with cisplatin or erlotinib and synergy may be mediated via erbB3/AKT signaling. MET is functionally important in HNSCC with prominent overexpression,increased gene copy number,and mutations. MET inhibition abrogated MET functions,including proliferation,migration/motility,and angiogenesis. MET is a promising,novel target for HNSCC and combination approaches with cisplatin or EGFR inhibitors should be explored. View Publication

Electrospun poly-l-lactic acid (PLLA) nanofiber mats carrying surface amine groups,previously introduced by nitrogen atmospheric pressure nonequilibrium plasma,are embedded into aqueous solutions of oligomeric acrylamide-end capped AGMA1,a biocompatible polyamidoamine with arg-gly-asp (RGD)-reminiscent repeating units. The resultant mixture is finally cured giving PLLA-AGMA1 hydrogel composites that absorb large amounts of water and,in the swollen state,are translucent,soft,and pliable,yet as strong as the parent PLLA mat. They do not split apart from each other when swollen in water and remain highly flexible and resistant,since the hydrogel portion is covalently grafted onto the PLLA nanofibers via the addition reaction of the surface amine groups to a part of the terminal acrylic double bonds of AGMA1 oligomers. Preliminary tested as scaffolds,the composites prove capable of maintaining short-term undifferentiated cultures of human pluripotent stem cells in feeder-free conditions. View Publication

We demonstrate an essential role for the proteasome complex in two proteolytic processes required for activation of the transcription factor NF-kappa B. The p105 precursor of the p50 subunit of NF-kappa B is processed in vitro by an ATP-dependent process that requires proteasomes and ubiquitin conjugation. The C-terminal region of p105 is rapidly degraded,leaving the N-terminal p50 domain. p105 processing can be blocked in intact cells with inhibitors of the proteasome or in yeast with proteasome mutants. These inhibitors also block the activation of NF-kappa B and the rapid degradation of I kappa B alpha induced by tumor necrosis factor alpha. Thus,the ubiquitin-proteasome pathway functions not only in the complete degradation of polypeptides,but also in the regulated processing of precursors into active proteins. View Publication

Astrocyte phenotypes change in a process called reactive gliosis after traumatic central nervous system (CNS) injury. Astrogliosis is characterized by expansion of the glial fibrillary acidic protein (GFAP) cytoskeleton,adoption of stellate morphologies,and differential expression of some extracellular matrix molecules. The astrocytic response immediately after injury is beneficial,but in the chronic injury phase,reactive astrocytes produce inhibitory factors (i.e.,chondroitin sulfate proteoglycans [CSPGs]) that limit the regrowth of injured axons. There are no drugs that promote axon regeneration or functional recovery after CNS trauma in humans. To develop novel therapeutics for the injured CNS,we screened various libraries in a phenotypic assay to identify compounds that promote neurite outgrowth. However,the effects these compounds have on astrocytes are unknown. Specifically,we were interested in whether compounds could alter astrocytes in a manner that mimics the glial reaction to injury. To test this hypothesis,we developed cell-based phenotypic bioassays to measure changes in (1) GFAP morphology/localization and (2) CSPG expression/immunoreactivity from primary astrocyte cultures. These assays were optimized for six-point dose-response experiments in 96-well plates. The GFAP morphology assay is suitable for counter-screening with a Z-factor of 0.44±0.03 (mean±standard error of the mean; N=3 biological replicates). The CSPG assay is reproducible and informative,but does not satisfy common metrics for a screenable" assay. As proof of principle we tested a small set of hit compounds from our neurite outgrowth bioassay and identified one that can enhance axon growth without exacerbating the deleterious characteristics of reactive gliosis. View Publication

Metabolic imaging of brain tumors using (13)C Magnetic Resonance Spectroscopy (MRS) of hyperpolarized [1-(13)C] pyruvate is a promising neuroimaging strategy which,after a decade of preclinical success in glioblastoma (GBM) models,is now entering clinical trials in multiple centers. Typically,the presence of GBM has been associated with elevated hyperpolarized [1-(13)C] lactate produced from [1-(13)C] pyruvate,and response to therapy has been associated with a drop in hyperpolarized [1-(13)C] lactate. However,to date,lower grade gliomas had not been investigated using this approach. The most prevalent mutation in lower grade gliomas is the isocitrate dehydrogenase 1 (IDH1) mutation,which,in addition to initiating tumor development,also induces metabolic reprogramming. In particular,mutant IDH1 gliomas are associated with low levels of lactate dehydrogenase A (LDHA) and monocarboxylate transporters 1 and 4 (MCT1,MCT4),three proteins involved in pyruvate metabolism to lactate. We therefore investigated the potential of (13)C MRS of hyperpolarized [1-(13)C] pyruvate for detection of mutant IDH1 gliomas and for monitoring of their therapeutic response. We studied patient-derived mutant IDH1 glioma cells that underexpress LDHA,MCT1 and MCT4,and wild-type IDH1 GBM cells that express high levels of these proteins. Mutant IDH1 cells and tumors produced significantly less hyperpolarized [1-(13)C] lactate compared to GBM,consistent with their metabolic reprogramming. Furthermore,hyperpolarized [1-(13)C] lactate production was not affected by chemotherapeutic treatment with temozolomide (TMZ) in mutant IDH1 tumors,in contrast to previous reports in GBM. Our results demonstrate the unusual metabolic imaging profile of mutant IDH1 gliomas,which,when combined with other clinically available imaging methods,could be used to detect the presence of the IDH1 mutation in vivo. View Publication

Despite significant advancements in targeted- and immunotherapies,millions of patients with cancer still succumb to the disease each year. In renal cell carcinoma,up to 25% of metastatic patients do not respond to first-line therapies. This reality underscores the urgent need for innovative or repurposed therapies to effectively treat these patients. Patient-derived organoids represent a promising model for evaluating treatment efficacy and toxicity,offering a potential breakthrough in personalized medicine. However,utilizing organoid models for drug screening presents several challenges. Our protocol aims to address these obstacles by outlining a practical approach to successfully isolate and cultivate patient-derived renal cell carcinoma and kidney organoids for treatment screening purposes. Graphical abstract Patient-derived organoids represent a promising model for evaluating treatment efficacy and toxicity,offering a potential breakthrough in personalized medicine. Nowak-Sliwinska and colleagues present a detailed protocol for obtaining kidney and kidney cancer organoids for drug development and precision oncology. View Publication

Activation-induced cytidine deaminase (AID) mediates immunoglobulin class switch DNA recombination (CSR) and somatic hypermutation (SHM),critical processes for maturation of the antibody response. Epigenetic factors,such as histone deacetylases (HDACs),would underpin B cell differentiation stage-specific AID expression. Here,we showed that NAD+-dependent class III HDAC sirtuin 1 (Sirt1) is highly expressed in resting B cells and down-regulated by stimuli inducing AID. B cell Sirt1 down-regulation,deprivation of NAD+ cofactor,or genetic Sirt1 deletion reduced deacetylation of Aicda promoter histones,Dnmt1,and nuclear factor-$\kappa$B (NF-$\kappa$B) p65 and increased AID expression. This promoted class-switched and hypermutated T-dependent and T-independent antibody responses or led to generation of autoantibodies. Genetic Sirt1 overexpression,Sirt1 boost by NAD+,or allosteric Sirt1 enhancement by SRT1720 repressed AID expression and CSR/SHM. By deacetylating histone and nonhistone proteins (Dnmt1 and NF-$\kappa$B p65),Sirt1 transduces metabolic cues into epigenetic changes to play an important B cell-intrinsic role in modulating antibody and autoantibody responses. View Publication

Gamma-glutamylcysteine synthetase (gammaGCS),a rate-limiting enzyme in glutathione biosynthesis,plays a central role in glutathione homeostasis and is a target for development of potential therapeutic agents against parasites and cancer. We have determined the crystal structures of Escherichia coli gammaGCS unliganded and complexed with a sulfoximine-based transition-state analog inhibitor at resolutions of 2.5 and 2.1 A,respectively. In the crystal structure of the complex,the bound inhibitor is phosphorylated at the sulfoximido nitrogen and is coordinated to three Mg2+ ions. The cysteine-binding site was identified; it is formed inductively at the transition state. In the unliganded structure,an open space exists around the representative cysteine-binding site and is probably responsible for the competitive binding of glutathione. Upon inhibitor binding,the side chains of Tyr-241 and Tyr-300 turn,forming a hydrogen-bonding triad with the carboxyl group of the inhibitor's cysteine moiety,allowing this moiety to fit tightly into the cysteine-binding site with concomitant accommodation of its side chain into a shallow pocket. This movement is caused by a conformational change of a switch loop (residues 240-249). Based on this crystal structure,the cysteine-binding sites of mammalian and parasitic gammaGCSs were predicted by multiple sequence alignment,although no significant sequence identity exists between the E. coli gammaGCS and its eukaryotic homologues. The identification of this cysteine-binding site provides important information for the rational design of novel gammaGCS inhibitors. View Publication

Characterization of pluripotent stem cells is required for the registration of stem cell lines and allows for an impartial and objective comparison of the results obtained when generating multiple lines. It is therefore crucial to establish specific,fast and reliable protocols to detect the hallmarks of pluripotency. Such protocols should include immunocytochemistry (takes 2 d),identification of the three germ layers in in vitro-derived embryoid bodies by immunocytochemistry (immunodetection takes 3 d) and detection of differentiation markers in in vivo-generated teratomas by immunohistochemistry (differentiation marker detection takes 4 d). Standardization of the immunodetection protocols used ensures minimum variations owing to the source,the animal species,the endogenous fluorescence or the inability to collect large amounts of cells,thereby yielding results as fast as possible without loss of quality. This protocol provides a description of all the immunodetection procedures necessary to characterize mouse and human stem cell lines in different circumstances. View Publication

The generation of endothelial progenitor cells (EPCs) from blood monocytes has been propagated as a novel approach in the diagnosis and treatment of cardiovascular diseases. Low-density lipoprotein (LDL) uptake and lectin binding together with endothelial marker expression are commonly used to define these EPCs. Considerable controversy exists regarding their nature,in particular,because myelomonocytic cells share several properties with endothelial cells (ECs). This study was performed to elucidate whether the commonly used endothelial marker determination is sufficient to distinguish supposed EPCs from monocytes. We measured endothelial,hematopoietic,and progenitor cell marker expression of monocytes before and after angiogenic culture by fluorescence microscopy,flow cytometry,and real-time reverse transcription-polymerase chain reaction. The function of primary monocytes and monocyte-derived supposed EPCs was investigated during vascular network formation and EC colony-forming unit (CFU-EC) development. Monocytes cultured for 4 to 6 days under angiogenic conditions lost CD14/CD45 and displayed a commonly accepted EPC phenotype,including LDL uptake and lectin binding,CD31/CD105/CD144 reactivity,and formation of cord-like structures. Strikingly,primary monocytes already expressed most tested endothelial genes and proteins at even higher levels than their supposed EPC progeny. Neither fresh nor cultured monocytes formed vascular networks,but CFU-EC formation was strictly dependent on monocyte presence. LDL uptake,lectin binding,and CD31/CD105/CD144 expression are inherent features of monocytes,making them phenotypically indistinguishable from putative EPCs. Consequently,monocytes and their progeny can phenotypically mimic EPCs in various experimental models. View Publication

Human embryonic stem cells (hESCs) offer exciting potential in regenerative medicine for the treatment of a host of diseases including cancer,Alzheimer's and Parkinson's disease. They also provide insight into human development and disease and can be used as models for drug discovery and toxicity analyses. The key properties of hESCs that make them so promising for medical use are that they have the ability to self-renew indefinitely in culture and they are pluripotent,which means that they can differentiate into any of more than 200 human cell types. Since proteins are the effectors of cellular processes,it is important to investigate hESC expression at the protein level as well as at the transcript level. In addition,post-translational modifications,such as phosphorylation,may influence the activity of pivotal proteins in hESCs,and this information can only be determined by studying the proteome. In this review,we summarize the results obtained from several proteomics analyses of hESCs that have been reported in the last few years. View Publication