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417 results on '"Fleming, Timothy"'

154. Circulating Tumor Cells in Patients with Breast Cancer Dormancy

Author

Meng, Songdong, primary, Tripathy, Debasish, additional, Frenkel, Eugene P., additional, Shete, Sanjay, additional, Naftalis, Elizabeth Z., additional, Huth, James F., additional, Beitsch, Peter D., additional, Leitch, Marilyn, additional, Hoover, Susan, additional, Euhus, David, additional, Haley, Barbara, additional, Morrison, Larry, additional, Fleming, Timothy P., additional, Herlyn, Dorothee, additional, Terstappen, Leon W. M. M., additional, Fehm, Tanja, additional, Tucker, Thomas F., additional, Lane, Nancy, additional, Wang, Jianqiang, additional, and Uhr, Jonathan W., additional

Published
2004
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161. Detection of Mammaglobin in the Sera of Patients with Breast Cancer

Author

Fanger, Gary R., primary, Houghton, Raymond L., additional, Retter, Marc W., additional, Hendrickson, Ron C., additional, Babcook, John, additional, Dillon, Davin C., additional, Durham, Margarita D., additional, Reynolds, Lisa D., additional, Johnson, Jeffrey C., additional, Carter, Darrick, additional, Fleming, Timothy P., additional, Roche, Patrick C., additional, Persing, David H., additional, and Reed, Steven G., additional

Published
2002
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175. Cross-dressed CD8α+/CD103+ dendritic cells prime CD8+ T cells following vaccination.

Author

Lijin Li, Sojung Kim, Herndon, John M., Goedegebuure, Peter, Belt, Brian A., Satpathy, Ansuman T., Fleming, Timothy P., Hansen, Ted H., Murphy, Kenneth M., and Gillanders, William E.

Subjects
DENDRITIC cells, CYTOTOXIC T cells, VACCINATION, CELL differentiation, VIRUS diseases, VIRAL antigens, IMMUNE response, CELLULAR immunity
Abstract

Activation of naïve cluster of differentiation (CD)8+ cytotoxic T lymphocytes (CTLs) is a tightly regulated process, and specific dendritic cell (DC) subsets are typically required to activate naive CTLs. Potential pathways for antigen presentation leading to CD8+ T-cell priming include direct presentation, cross-presentation, and cross-dressing. To distinguish between these pathways, we designed single-chain trimer (SCT) peptide-MHC class I complexes that can be recognized as intact molecules but cannot deliver antigen to MHC through conventional antigen processing. We demonstrate that cross-dressing is a robust pathway of antigen presentation following vaccination, capable of efficiently activating both naive and memory CD8+ T cells and requires CD8a+/ CD103+ DCs. Significantly, immune responses induced exclusively by cross-dressing were as strong as those induced exclusively through cross-presentation. Thus, cross-dressing is an important pathway of antigen presentation, with important implications for the study of CD8+ T-cell responses to viral infection, tumors, and vaccines. [ABSTRACT FROM AUTHOR]

Published
2012
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177. Performance Improvements in the Relativistic Magnetron: The Effect of DC Field Perturbations.

Author

Fleming, Timothy P. and Mardahl, Peter J.

Subjects
*MAGNETRONS, *DIRECT current in electric power distribution, *DIRECT currents, *DIRECT current circuits, *ELECTRIC fields, *MAGNETIC fields, *FIELD theory (Physics)
Abstract

The effect of using a shaped or transparent cathode to enhance key performance parameters in the Michigan magnetron, such as output power, power efficiency, and mode purity, was examined using a massively parallel electromagnetic particle-in-cell code Improved Concurrent Electromagnetic Particle-In-Cell. In simulations, we saw a dramatic increase in the range of magnetic field and input voltage over which the magnetron functions, an increase in output power, an increase in efficiency, an elimination of mode competition, and immediate start-up for both the shaped and transparent cathodes relative to the standard cathode. These simulations also revealed that the mechanism that is responsible for the improved performance that accompanies the transparent cathode may not be RF-azimuthal-field penetration but rather perturbations in the "dc" field resulting from the design of the novel cathodes themselves. [ABSTRACT FROM AUTHOR]

Published
2009
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178. Mammaglobin as a potential molecular target for breast cancer drug delivery.

Author

Lian Zuo, Ly Li, Qian Wang, Fleming, Timothy P., and Shaojin You

Subjects
BREAST cancer research, BIOMARKERS, WESTERN immunoblotting, CANCER cells, LOW density lipoproteins
Abstract

Background: Mammaglobin (MAM) has been used as a specific molecular marker for breast cancer diagnosis. Recently, several groups of researchers proposed a number of therapeutic strategies targeting this molecule. Some of the strategies are based upon an essential but not demonstrated hypothesis -- mammaglobin is associated with the surface of breast cancer cells, which strongly disputes the therapeutic strategies. Results: We conducted a computer-based predictive analysis and identified a small fragment at the N-end of MAM as a potential transmembrane domain. We provided several evidences to demonstrate the presence of the membrane-associated MAM. We isolated the membrane protein components from known MAM positive breast cancer cells (MDA-MB361 and MDA-MB415). We showed that about 22-64% of MAM proteins, depending upon the types of the cancer cells, directly attached on the membrane of breast cancer cells, by Western blotting assays. To directly visualize the presence of the membrane-bound MAM protein, we incubated the MAM positive cancer cells with FITC labeled anti-MAM antibody, and observed clear fluorescent signals on the surface of the cells. In studying the MAM protein distribution in human breast cancer tissues, we first identified two immunostain patterns that are associated with the membrane-bound MAM: the membrane stain pattern and luminary surface stain pattern. To test whether the membrane-associated MAM can serve as a molecular target for drug delivery, we conjugated anti-MAM antibody to human low-density lipoprotein (LDL) and loaded doxorubicin (Dox) in the core of LDL. Specific binding and cytotoxicity of the MAM targeted and Dox loaded LDL was tested in the MAM positive breast cancer cells in vitro. Conclusion: We first showed that some of MAM protein directly associated with the surface of breast cancer cells. The membrane-associated MAM protein may be utilized as a useful molecular marker for breast cancer targeted drug delivery. [ABSTRACT FROM AUTHOR]

Published
2009
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183. Tat mammaglobin fusion protein transduced dendritic cells stimulate mammaglobin-specific CD4 and CD8 T cells

Author

Viehl, Carsten T., Tanaka, Yoshiyuki, Chen, Tingting, Frey, Daniel M., Tran, Andrew, Fleming, Timothy P., Eberlein, Timothy J., and Goedegebuure, Peter S.

Abstract

Summary Proteins can be efficiently introduced into cells when fused to a protein transduction domain, such as Tat from the human immunodeficiency virus. We recently reported that dendritic cells transduced with a Tat fusion protein containing the extracellular domain of Her2/neu (Tat-Her2/neu) induced CD8 cytotoxic T lymphocytes (CTL) that specifically lysed Her2/neu-expressing breast and ovarian cancer cells. In the current study we further investigated the mechanism of protein transduction, utilizing the breast cancer-associated protein, mammaglobin-A, which is expressed in about 80% of breast cancers. Using a Tat-mammaglobin fusion protein, we tested the ability of Tat-mammaglobin transduced dendritic cells to stimulate antigen-specific CD4 and CD8 T cells. Low levels of serum considerably improved protein transduction as determined by Western blot, and also improved presentation of antigenic peptide as evidenced by functional studies using antigen-specific T cells. Confocal microscope analyses of antigen-presenting cells (APC) incubated with Tat-mammaglobin showed localized distribution in addition to diffuse distribution in the cytosol. In contrast, mammaglobin lacking Tat showed only a localized distribution. Simultaneous incubation with both proteins resulted in overlapping localized distributions, suggesting Tat fusion proteins are processed through both the MHC class I and class II pathways. Indeed, stimulation of T cells with Tat-mammaglobin transduced dendritic cells led to an expansion of mammaglobin-specific CD4 T helper-1 lymphocytes along with CD8 CTL. We conclude that Tat-mammaglobin transduced dendritic cells can induce both CD4 and CD8 mammaglobin-specific T cells. These findings could be further exploited for the development of a mammaglobin-based vaccine for breast cancer.

Published
2005
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184. PEA3, AP-1, and a unique repetitive sequence all are involved in transcriptional regulation of the breast cancer-associated gene, mammaglobin

Author

Hesselbrock, Diane, Kurpios, Natasza, Hassell, John, Watson, Mark, and Fleming, Timothy

Abstract

Summary: The breast cancer-associated gene mammaglobin is a member of the secretoglobin protein family and has demonstrated its utility as a breast cancer marker. However, the transcriptional regulation of mammaglobin has not been well-characterized. In this report, we used luciferase reporter assays to identify the 200 bp directly 5rsquo of the transcriptional start site as the minimal promoter region of mammaglobin. Sequence scanning indicated that two PEA3 transcription sites were possibly involved in mammaglobin transcription. By transfecting a PEA3 expression vector into breast cancer cell lines MDA-MB-415 and MCF-7, we determined that exogenous PEA3 was able to drive transcription. Mutational analysis indicated that each PEA3 site was functional. Our reporter system and electrophorectic mobility shift assays (EMSAs) also identified the involvement of a unique repetitive element in mammaglobin transcription. Finally, AP-1 was determined via luciferase assays to be involved in regulating non-PEA3 dependent transcription. Elucidating these cis-acting elements will impact our understanding of transcription of normal breast and breast cancer-associated genes.

Published
2005
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185. Recognition of HLA-A2-restricted mammaglobin-A-derived epitopes

Author

Jaramillo, André, Narayanan, Kishore, Campbell, Lacey, Benshoff, Nicholas, Lybarger, Lonnie, Hansen, Ted, Fleming, Timothy, Dietz, Jill, and Mohanakumar, T.

Abstract

A breast cancer-associated antigen, mammaglobin-A, is specifically expressed in 80% of primary breast tumors. The definition of immune responses against this highly expressed breast cancer-specific antigen should be of great value in the development of new therapeutic strategies for breast cancer. Thus, the purpose of this study was to identify HLA-A2-restricted mammaglobin-A-derived epitopes recognized by CD8+ cytotoxic T lymphocytes (CTL). We identified seven mammaglobin-A-derived candidate epitopes that bind the HLA-A2 molecule (Mam-A2.1-7) by means of a HLA class I-peptide binding computer algorithm from the Bioinformatics & Molecular Analysis Section of the National Institutes of Health. Subsequently, we determined that CD8+ CTLs from breast cancer patients reacted to the Mam-A2.1 (83–92, LIYDSSLCDL), Mam-A2.2 (2–10, KLLMVLMLA), Mam-A2.3 (4–12, LMVLMLAAL), Mam-A2.4 (66–74, FLNQTDETL), and Mam-A2.7 (32–40, TINPQVSKT) epitopes using an IFN-c ELISPOT assay. Interestingly, healthy individuals also showed high reactivity to the Mam-A2.2 epitope. Two CD8+ CTL lines generated in vitro against TAP-deficient T2 cells loaded with the candidate epitopes showed significant cytotoxic activity against the Mam-A2.1-4 epitopes. These CD8+CTL lines recognized a HLA-A2+breast cancer cell line expressing the Mam-A2.1 epitope. In addition, DNA vaccination of HLA-A2+/human CD8+ double-transgenic mice with a DNA construct encoding the Mam-A2.1 epitope and the HLA-A2 molecule induced a significant expansion of epitope-specific CD8+ CTLs that recognize the same HLA- A2+/Mam-A2.1+ breast cancer cell line. In conclusion, these results demonstrate the immunotherapeutic potential of mammaglobin-A for the treatment and prevention of breast cancer.

Published
2004
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186. Generation of CD8+ Cytotoxic T Lymphocytes Against Breast Cancer Cells by Stimulation with Mammaglobin-A-Pulsed Dendritic Cells

Author

Manna, Partha, Jaramillo, Andrés, Majumder, Kanchana, Campbell, Lacey, Fleming, Timothy, Dietz, Jill, Dipersio, John, and Mohanakumar, T.

Abstract

Mammaglobin-A is exclusively expressed by breast cancer cells. Thus, mammaglobin-A-specific T cell immune responses may be useful for the design of new breast cancer-specific immunotherapies. We show herein that CD8+ T cells generated against recombinant mammaglobin-A-pulsed dendritic cells display a marked cytotoxic activity against mammaglobin-A-positive breast cancer cell lines. This study indicates the immunotherapeutic potential of this novel antigen for the treatment of breast cancer.

Published
2003
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187. SARS‐CoV‐2 infection in lung transplant recipients induces circulating exosomes with SARS‐CoV‐2 spike protein S2.

Author

Bansal, Sandhya, Tokman, Sofya, Fleming, Timothy, Maine, Gabriel N., Sanborn, Kristina, Hachem, Ramsey, Bharat, Ankit, Smith, Michael A., Bremner, Ross M., and Mohanakumar, T.

Subjects
*COVID-19, *EXOSOMES, *SARS-CoV-2, *LUNG transplantation, *LUNG infections, *REGULATORY T cells
Abstract

TEM and immunostaining of the exosomes using Abs specific to SARS-CoV-2 spike protein S2 and nucleocapsid protein revealed the presence of the spike protein S2 and nucleocapsid antigen on the surface of exosomes (Figure 3A). SARS-CoV-2 spike protein S2 in the exosomes also suggests that the exosomes acquire the spike protein antigen during active infection. SARS-CoV-2 infection in lung transplant recipients induces circulating exosomes with SARS-CoV-2 spike protein S2. [Extracted from the article]

Published
2021
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188. The Endowment Effect in Orangutans

Author

Owen D. Jones, Fleming, Timothy M., Laura Mayo, Tara Stoinski, and Sara Brosnan

Subjects
General Psychology, International Journal of Comparative Psychology, Behavior, Behaviour, Communication, Vocalization, Comparative Psychology, Orangutan, Pongo, Cognition, Cognitive Processes, Intelligence, Endowment, Human Language, Primates
Abstract

The endowment effect is the tendency to, seemingly irrationally, immediately value a possessed item more than the opportunity to acquire the identical item when one does not already possess it. Although endowment effects are reported in chimpanzees (Brosnan, Jones, Lambeth, Mareno,Richardson, & Shapiro, 2007) and capuchin monkeys (Lakshminarayanan, Chen, & Santos, 2008), both species share social traits with humans that make convergence as likely an evolutionary mechanism as homology. Orangutans (Pongo spp.) provide a unique insight into the evolution of the endowment effect, along with other apparently irrational behaviors, because their less frequent socialinteractions and relatively more solitary social organization distinguishes them from the more gregarious apes, allowing a test of evolutionary homology. In the present study, we used pairs of both food and non-food objects, as in an earlier test on chimpanzees (Brosnan et al., 2007). We established the apes’ preferences in forced -choice tasks, then tested whether they showed an endowment effect inan exchange task, in which subjects were given one of the objects, followed by the option to exchange it for the other. Here, we report the first evidence of the endowment effect in a relatively less social primate, the orangutan. This indicates that this behavior may have evolved as a homology within the primates, rather than being due to convergent social pressures. These findings provide stronger evidence for the hypothesis that at least one bias, the endowment effect, may be common in primates and, potentially, other species.

198. Cancer-associated mutations reveal a novel role for EpCAM as an inhibitor of cathepsin-L and tumor cell invasion.

Author

Sankpal, Narendra V., Brown, Taylor C., Fleming, Timothy P., Herndon, John M., Amaravati, Anusha A., Loynd, Allison N., and Gillanders, William E.

Abstract

Background: EpCAM (Epithelial cell adhesion molecule) is often dysregulated in epithelial cancers. Prior studies implicate EpCAM in the regulation of oncogenic signaling pathways and epithelial-to-mesenchymal transition. It was recently demonstrated that EpCAM contains a thyroglobulin type-1 (TY-1) domain. Multiple proteins with TY-1 domains are known to inhibit cathepsin-L (CTSL), a cysteine protease that promotes tumor cell invasion and metastasis. Analysis of human cancer sequencing studies reveals that somatic EpCAM mutations are present in up to 5.1% of tested tumors.Methods: The Catalogue of Somatic Mutations in Cancer (COSMIC) database was queried to tabulate the position and amino acid changes of cancer associated EpCAM mutations. To determine how EpCAM mutations affect cancer biology we studied C66Y, a damaging TY-1 domain mutation identified in liver cancer, as well as 13 other cancer-associated EpCAM mutations. In vitro and in vivo models were used to determine the effect of wild type (WT) and mutant EpCAM on CTSL activity and invasion. Immunoprecipitation and localization studies tested EpCAM and CTSL protein binding and determined compartmental expression patterns of EpCAM mutants.Results: We demonstrate that WT EpCAM, but not C66Y EpCAM, inhibits CTSL activity in vitro, and the TY-1 domain of EpCAM is responsible for this inhibition. WT EpCAM, but not C66Y EpCAM, inhibits tumor cell invasion in vitro and lung metastases in vivo. In an extended panel of human cancer cell lines, EpCAM expression is inversely correlated with CTSL activity. Previous studies have demonstrated that EpCAM germline mutations can prevent EpCAM from being expressed at the cell surface. We demonstrate that C66Y and multiple other EpCAM cancer-associated mutations prevent surface expression of EpCAM. Cancer-associated mutations that prevent EpCAM cell surface expression abrogate the ability of EpCAM to inhibit CTSL activity and tumor cell invasion.Conclusions: These studies reveal a novel role for EpCAM as a CTSL inhibitor, confirm the functional relevance of multiple cancer-associated EpCAM mutations, and suggest a therapeutic vulnerability in cancers harboring EpCAM mutations. [ABSTRACT FROM AUTHOR]

Published
2021
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200. Predictive, optimized numerical simulation of microwave generation in complex geometries with real materials.

Author

Peterkin, Robert E., Fleming, Timothy P., French, David M., Gensheimer, Paul D., Greenwood, Andrew D., Hoff, Brad W., Karrels, Daniel R., Lambrecht, Michael, Lockwood, Nathaniel P., Mardahl, Peter J., and Tang, Wilkin W.

Abstract

Predictive numerical simulation of microwave generation and plasma interactions requires resolution of multiple length and time scales in complex 3-dimensional geometries. The Particle-in-Cell (PIC) method for the numerical formulation of the basic governing equations is a well-understood and reliable approach if we are able to assume that short-range collisional effects are on average small. Particle collisions can be included in the PIC formulation through the use of Monte Carlo Collision models, and non-linear materials for which the permittivity depends on the strength of applied fields can be incorporated into the PIC formulation if proper attention is paid to issues of numerical stability of the expanded set of governing equations. Accurate modeling of time-dependent physics in complex geometries requires careful formulation of the numerical equations and the dynamic ability to evolve the image of a decomposed domain across thousands of computational cores. [ABSTRACT FROM PUBLISHER]

Published
2012
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