Browsing by Subject "signaling pathways"

Now showing 1 - 3 of 3
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    Does spinophilin play a role in alteration of NMDAR phosphorylation?
    (Office of the Vice Chancellor for Research, 2016-04-08) Salek, Asma B.; McBride, Jonathon; Edler Jr., Michael C.; Baucum II, Anthony J.
    Normal brain function requires proper organization of downstream signaling pathways. This organization can be modulated by protein phosphorylation. Protein phosphorylation is a balance of phosphatases, such as protein phosphatase 1 (PP1), and kinases such as protein kinase A (PKA) and cyclin dependent kinase 5 (CDK5). Proper targeting of these proteins is critical for their normal function and is perturbed in various disease states. Spinophilin is critical in targeting PP1 to various substrates making it important in regulating the phosphorylation state and thus the function of various proteins including glutamate receptors, such as AMPARs and NMDARs. NMDARs are abundant postsynaptic proteins that are critical for normal synaptic communication. It has been reported that NMDAR phosphorylation modulates channel function. Here we aim to understand if spinophilin regulates NMDAR phosphorylation and function as well as the mechanisms by which the spinophilin NMDAR interaction are altered. Specifically, we have found that the presence of spinophilin decreases the abundance of PP1 bound to NMDAR. This affect was not observed when a PP1 binding-deficient spinophilin mutant (F451A) was expressed. Furthermore, activation of endogenous PKA and/or overexpression of PKA catalytic subunit robustly increased the association between spinophilin and GluN1 and C-terminal tail of the GluN2B subunit of the NMDAR. Conversely, these associations are decreased when CDK5 is present. Our future studies will evaluate the role of spinophilin in regulating the phosphorylation state of the NMDAR. Taken together, our data demonstrate that spinophilin can associate with multiple subunits of the NMDAR in HEK293 cells and that protein kinases can biphasically modulate these associations.
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    Mechanisms of Intrinsic Tumor Resistance to Immunotherapy
    (MDPI, 2018-05-02) Rieth, John; Subramanian, Subbaya; Surgery, School of Medicine
    An increased understanding of the interactions between the immune system and tumors has opened the door to immunotherapy for cancer patients. Despite some success with checkpoint inhibitors including ipilimumab, pembrolizumab, and nivolumab, most cancer patients remain unresponsive to such immunotherapy, likely due to intrinsic tumor resistance. The mechanisms most likely involve reducing the quantity and/or quality of antitumor lymphocytes, which ultimately are driven by any number of developments: tumor mutations and adaptations, reduced neoantigen generation or expression, indoleamine 2,3-dioxygenase (IDO) overexpression, loss of phosphatase and tensin homologue (PTEN) expression, and overexpression of the Wnt–β-catenin pathway. Current work in immunotherapy continues to identify various tumor resistance mechanisms; future work is needed to develop adjuvant treatments that target those mechanisms, in order to improve the efficacy of immunotherapy and to expand its scope.
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    QUANTITATIVE IMMUNOHISTOCHEMISTRY USING THE APERIO WHOLE SLIDE IMAGING SYSTEM EVALUATING ANGIOGENESIS AND HYPOXIA MARKERS IN PANCREATIC CARCINOMA MOUSE MODEL TREATED WITH VEHICLE CONTROL, E3330, AND A STAT 3 INHIBITOR
    (Office of the Vice Chancellor for Research, 2012-04-13) Spencer, Cleandrea; Sandusky, George; Fishel, Melissa; Kelley, Mark R.
    Investigation of the signaling pathways and molecular mechanisms that are major contributors to pancreatic tumor progression and its resistance to traditional therapies is lacking. Human apurinic endonuclease/redox factor 1 (APE/Ref-1) mediates repair of radiation-induced DNA lesions and regulates transcription via redox-based activation. Transcriptional factors HIF-1α, NFκB, and AP-1 are regulated by Ref-1 and are implicated in pancreatic tu-mor growth and the response to hypoxia. CD31 and CA IX (carbonic anhy-drase) were biomarkers used in an in vivo study to evaluate the effective-ness of E3330, an APE 1 inhibitor, in a pancreatic mouse model. Immunostained slides were scanned using the Aperio automated whole slide scanning system (Scanscope CS) and were viewed using ImageScopeTM. Single fields of view from each WSDI measuring ∼10,000,000 μm2 and rep-resenting the whole area of the tumor were selected for analysis using the Aperio positive pixel algorithm. The preclinical xenograft model evaluated human pancreatic carcinoma cell lines grown in NOD/SCID mice treated with the E3330 compound, a STAT 3 inhibitor, and an untreated vehicle control group. Immunohisto-chemistry (IHC) was used to predict effectiveness of treatment for pancreat-ic carcinoma based on CD31 and CA IX biomarker expression. IHC slides were quantified using both a traditional pathology hand count and the Aperio Imaging Analysis System. The positive pixel algorithm data closely mirrored the hand count for two biomarkers (CD31 and CA IX). In the E3330 treated group, the data showed CD31 (angiogenesis) was significantly knocked down with increased CA IX expression compared to the vehicle control. Hypoxia of the tumor cells was up in both treated groups. In summary, the Aperio im-aging analysis system matched the hand count pathology data. The drug ef-fects with E3330 exhibited both anti-angiogenesis and tumor hypoxia activi-ty in the tumors. This project was supported by the Center for Research and Learning’s Diversity Scholars Re-search Program.