scholarly journals IGF-1R nuclear import and recruitment to chromatin involves both alpha and beta subunits

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jack V. Mills ◽  
Eliot Osher ◽  
Guillaume Rieunier ◽  
Ian G. Mills ◽  
Valentine M. Macaulay

AbstractMature type 1 insulin-like growth factor receptors (IGF-1Rs) are heterotetrameric structures comprising two extracellular α-subunits disulphide-bonded to two transmembrane β-subunits with tyrosine kinase activity. IGF-1R is a well-known cell surface mediator of malignant growth, with an incompletely understood role upon nuclear import as a transcriptional regulator. Previous characterisation of nuclear IGF-1R focused on IGF-1Rβ. Here, we aimed to clarify the source of nuclear IGF-1R and investigate whether α-subunits contribute to nuclear IGF-1R function. Using prostate cancer cell lines DU145 and 22Rv1 we detected nuclear α- and β-subunits, with increase in nuclear signal upon IGF-treatment and reduction in response to IGF-1R inhibitor BMS-754807. Following biotinylation of cell surface proteins, biotinylated α- and β-subunits were detected in nuclear extracts of both cell lines. Furthermore, α- and β-subunits reciprocally co-precipitated from nuclear extract. Finally, we detected recruitment of both subunits to regulatory regions of chromatin, including the promoter of the oncogene JUN, that we previously identified in ChIP-seq as sites of IGF-1Rβ enrichment. These data confirm the cell surface origin of nuclear IGF-1R, suggest the presence of nuclear αβ complexes and reveal that both IGF-1Rα- and β-subunits contribute to pro-tumorigenic functions of nuclear IGF-1R.

1990 ◽  
Vol 273 (3) ◽  
pp. 287-299
Author(s):  
Firdausi Qadri ◽  
Rubhana Raqib ◽  
Ishrat Ara Husain ◽  
Ivan Čižnár

2009 ◽  
Vol 21 (1) ◽  
pp. 241
Author(s):  
K. J. Williams ◽  
R. A. Godke ◽  
K. R. Bondioli

Human adipose tissue-derived adult stem (ADAS) cells are a self-renewing population of cells with a multilineage plasticity similar to bone marrow-derived mesenchymal stem cells. Human ADAS have promise for use in combination with various biomaterials for reconstructive tissue engineering. The phenotypic profile of human ADAS cell surface proteins has been partially characterized for stem cell-associated cluster differentiation molecules including CD29, CD44, and CD90. Porcine ADAS cells, an animal model for tissue engineering, also have the ability to self-renew and differentiate into multiple tissue lineages. However, the surface protein phenotype has not been described. Because porcine ADAS are isolated from fat depots likely different from human ADAS liposuction aspirates, it is important to characterize these cells. In this study, we have partially characterized the surface protein phenotype of undifferentiated porcine ADAS cells in comparison with the immunophenotype of undifferentiated human ADAS cells as reported in the literature. Flow cytometry and enhanced chemiluminescence Western blot analysis of early passage (passages 0–4) porcine ADAS cell populations demonstrated that the profiles are not similar to the human ADAS cell surface. Immunoblot detection paired with an enhanced chemiluminescence kit revealed a positive expression for CD44 and CD90 in human ADAS cells as indicated by bands present at the expected sizes and a negative expression for CD44 and CD90 in porcine ADAS cells. Flow cytometric analysis also indicated differences between human and early passage porcine ADAS cell surfaces with a relatively low expression of CD29 (5 cell lines with a mean percent positive of 4.5 ± 1.7 and a range of 2.5–7.2%) and CD44 (5 cell lines with a mean percent positive of 0.66 ± 0.67 and a range of 0.0–1.8%) compared with human ADAS values of 98 ± 1 and 60 ± 15, respectively (Gronthos et al. 2001). Other cell surface proteins analyzed at early passages include CD3 (3 cell lines; 0.07 ± 0.06% positive and 0.0–0.1 range), CD8 (3 cell lines; 0.10 ± 0.10% positive and 0–0.2 range), and CD90 [5 cell lines; 12.7 ± 11.9% positive and 2.4–33 range; human ADAS geometric mean 25.96% (Zuk et al. 2002)]. Analysis of late passage (passages 5–11) porcine ADAS cell populations revealed an increased expression of CD29 (3 cell lines; 26.4 ± 7.2% positive and 21.2–34.6 range). The expression level of CD90 at late passages were 21.3 and 26.9% positive for 2 cell lines and CD44 remained low (3 cell lines; 4.1 ± 3.5% positive and 0.2–7.0 range). Later passages were also analyzed for c-Kit (CD117), which was expressed at low levels (2 cell lines; 0.3 and 0.4% positive). The characterization of adipose tissue-derived adult stem cell surface proteins present at different stages of in vitro culture from a model animal, such as the pig, could have valuable impacts on tissue engineering research. These results suggest that care should be taken when interpreting results from animal models of somatic stem cells.


2002 ◽  
Vol 76 (24) ◽  
pp. 12723-12734 ◽  
Author(s):  
Kathryn S. Jones ◽  
Manisha Nath ◽  
Cari Petrow-Sadowski ◽  
Andrea C. Baines ◽  
Megan Dambach ◽  
...  

ABSTRACT Little is known about the requirements for human T-cell leukemia virus type 1 (HTLV-1) entry, including the identity of the cellular receptor(s). Previous studies have shown that although the HTLV receptor(s) are widely expressed on cell lines of various cell types from different species, cell lines differ dramatically in their susceptibility to HTLV-Env-mediated fusion. Human cells (293, HeLa, and primary CD4+ T cells) showed higher levels of binding at saturation than rodent (NIH 3T3 and NRK) cells to an HTLV-1 SU immunoadhesin. A direct comparison of the binding of the HTLV-1 surface glycoprotein (SU) immunoadhesin and transduction by HTLV-1 pseudotyped virus revealed parallels between the level of binding and the titer for various cell lines. When cells were treated with phorbol myristate acetate (PMA), which down-modulates a number of cell surface molecules, the level of SU binding was markedly reduced. However, PMA treatment only slightly reduced the titer of murine leukemia virus(HTLV-1) on both highly susceptible and poorly susceptible cells. Treatment of target cells with trypsin greatly reduced binding, indicating that the majority of HTLV SU binding is to proteins. Polycations, which enhance the infectivity of several other retroviruses, inhibited HTLV-1 Env-mediated binding and entry on both human and rodent cells. These results suggest that factors other than the number of primary binding receptors are responsible for the differences in the titers of HTLV-1 pseudotypes between highly susceptible cells and poorly susceptible cells.


2021 ◽  
Vol 12 ◽  
Author(s):  
Mélanie Rose ◽  
Tristan Cardon ◽  
Soulaimane Aboulouard ◽  
Nawale Hajjaji ◽  
Firas Kobeissy ◽  
...  

Glioblastoma (GBM) is the most common and devastating malignant brain tumor in adults. The mortality rate is very high despite different treatments. New therapeutic targets are therefore highly needed. Cell-surface proteins represent attractive targets due to their accessibility, their involvement in essential signaling pathways, and their dysregulated expression in cancer. Moreover, they are potential targets for CAR-based immunotherapy or mRNA vaccine strategies. In this context, we investigated the GBM-associated surfaceome by comparing it to astrocytes cell line surfaceome to identify new specific targets for GBM. For this purpose, biotinylation of cell surface proteins has been carried out in GBM and astrocytes cell lines. Biotinylated proteins were purified on streptavidin beads and analyzed by shotgun proteomics. Cell surface proteins were identified with Cell Surface Proteins Atlas (CSPA) and Gene Ontology enrichment. Among all the surface proteins identified in the different cell lines we have confirmed the expression of 66 of these in patient’s glioblastoma using spatial proteomic guided by MALDI-mass spectrometry. Moreover, 87 surface proteins overexpressed or exclusive in GBM cell lines have been identified. Among these, we found 11 specific potential targets for GBM including 5 mutated proteins such as RELL1, CYBA, EGFR, and MHC I proteins. Matching with drugs and clinical trials databases revealed that 7 proteins were druggable and under evaluation, 3 proteins have no known drug interaction yet and none of them are the mutated form of the identified proteins. Taken together, we discovered potential targets for immune therapy strategies in GBM.


2018 ◽  
Author(s):  
Kevin K Leung ◽  
Aaron Nguyen ◽  
Tao Shi ◽  
Lin Tang ◽  
Xiaochun Ni ◽  
...  

AbstractMyelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) are diseases of abnormal hematopoietic differentiation with aberrant epigenetic alterations. Azacitidine (AZA) is a DNA methyltransferase inhibitor (DNMTi) widely used to treat MDS and AML, yet the impact of AZA on the cell surface proteome has not been defined. To identify potential therapeutic targets for use in combination with AZA in AML patients, we investigated the effects of AZA treatment on four AML cell lines (KG1a, HL60, HNT34, and AML193), representing different stages of differentiation. The effect of AZA treatment on these cell lines was characterized at three levels: the DNA methylome (methylation array), the transcriptome (gene expression array), and the cell surface proteome (glycoprotein capture with SILAC labeling). Untreated AML cell lines showed substantial overlap in their methylomes, transcriptomes, and cell surface proteomes. AZA treatment globally reduced DNA methylation in all cell lines, but changes in the transcriptome and surface proteome were subtle and differed among the cell lines. Transcriptome analysis identified five commonly up-regulated coding genes upon AZA treatment in all four cell lines, TRPM4 being the only gene encoding a surface protein, and surface proteomics analysis found no commonly regulated proteins. Gene Set Enrichment Analysis (GSEA) of differentially-regulated RNA and surface proteins showed a decrease in metabolism pathways and an increase in immune defense response pathways. As such, AZA treatment in four AML cell lines had diverse effects at the individual gene and protein level, but converged to regulation of metabolism and immune response at the pathway level. Given the heterogeneous response of AZA in the four cell lines at the gene and protein level, we discuss potential therapeutic strategies for combinations with AZA.


Biochimie ◽  
1976 ◽  
Vol 58 (6) ◽  
pp. 731-736 ◽  
Author(s):  
Myriam Bettane ◽  
Brigitte Hermier ◽  
Jean-Marie Dubert ◽  
Alain Paraf

2001 ◽  
Vol 75 (2) ◽  
pp. 834-843 ◽  
Author(s):  
Scott F. Walk ◽  
Melissa Alexander ◽  
Bernhard Maier ◽  
Marie-Louise Hammarskjold ◽  
David M. Rekosh ◽  
...  

ABSTRACT The Nef protein of the human immunodeficiency virus type 1 (HIV-1) has been shown to enhance the infectivity of virus particles, downmodulate cell surface proteins, and associate with many intracellular proteins that are thought to facilitate HIV infection. One of the challenges in defining the molecular events regulated by Nef has been obtaining good expression of Nef protein in T cells. This has been attributed to effects of Nef on cell proliferation and apoptosis. We have designed a Nef protein that is readily expressed in T-cell lines and whose function is inducibly activated. It is composed of a fusion between full-length Nef and the estrogen receptor hormone-binding domain (Nef-ER). The Nef-ER is kept in an inactive state due to steric hindrance, and addition of the membrane-permeable drug 4-hydroxytamoxifen (4-HT), which binds to the ER domain, leads to inducible activation of Nef-ER within cells. We demonstrate that Nef-ER inducibly associates with the 62-kDa Ser/Thr kinase and is localized to specific membrane microdomains (lipid rafts) only after activation. Using this inducible Nef, we also compared the specific requirements for CD4 and HLA-A2 downmodulation in a SupT1 T-cell line. Half-maximal downmodulation of cell surface CD4 required very little active Nef-ER and occurred as early as 4 h after addition of 4-HT. In contrast, 50% downmodulation of HLA-A2 by Nef required 16 to 24 h and about 50- to 100-fold-greater concentrations of 4-HT. These data suggest that HLA-A2 downmodulation may require certain threshold levels of active Nef. The differential timing of CD4 and HLA-A2 downmodulation may have implications for HIV pathogenesis and immune evasion.


2021 ◽  
Vol 118 (4) ◽  
pp. e2018861118
Author(s):  
Wentao Chen ◽  
Kurt Yun Mou ◽  
Paige Solomon ◽  
Rahul Aggarwal ◽  
Kevin K. Leung ◽  
...  

MYC is a powerful transcription factor overexpressed in many human cancers including B cell and prostate cancers. Antibody therapeutics are exciting opportunities to attack cancers but require knowledge of surface proteins that change due to oncogene expression. To identify how MYC overexpression remodels the cell surface proteome in a cell autologous fashion and in different cell types, we investigated the impact of MYC overexpression on 800 surface proteins in three isogenic model cell lines either of B cell or prostate cell origin engineered to have high or low MYC levels. We found that MYC overexpression resulted in dramatic remodeling (both up- and down-regulation) of the cell surfaceome in a cell type-dependent fashion. We found systematic and large increases in distinct sets of >80 transporters including nucleoside transporters and nutrient transporters making cells more sensitive to toxic nucleoside analogs like cytarabine, commonly used for treating hematological cancers. Paradoxically, MYC overexpression also increased expression of surface proteins driving cell turnover such as TNFRSF10B, also known as death receptor 5, and immune cell attacking signals such as the natural killer cell activating ligand NCR3LG1, also known as B7-H6. We generated recombinant antibodies to these two targets and verified their up-regulation in MYC overexpression cell lines and showed they were sensitive to bispecific T cell engagers (BiTEs). Our studies demonstrate how MYC overexpression leads to dramatic bidirectional remodeling of the surfaceome in a cell type-dependent but functionally convergent fashion and identify surface targets or combinations thereof as possible candidates for cytotoxic metabolite or immunotherapy.


2000 ◽  
Vol 44 (1) ◽  
pp. 51-56 ◽  
Author(s):  
Julià Blanco ◽  
Jordi Barretina ◽  
Geoffrey Henson ◽  
Gary Bridger ◽  
Erik De Clercq ◽  
...  

ABSTRACT Infection by human immunodeficiency virus type 1 (HIV-1) has been associated with increased cell death by apoptosis in infected and uninfected cells. The envelope glycoprotein complex ([gp120/gp41]n) of X4 HIV-1 isolates is involved in both infected and uninfected cell death via its interaction with cellular receptors CD4 and CXCR4. We studied the effect of the blockade of CXCR4 receptors by the agonist stromal derived factor (SDF-1α) and the antagonist bicyclam AMD3100 on apoptotic cell death of CD4+cells in different models of HIV infection. In HIV-infected CEM or SUP-T1 cultures, AMD3100 showed antiapoptotic activity even when added 24 h after infection. In contrast, other antiviral agents, such as zidovudine, failed to block apoptosis under these conditions. The antiapoptotic activity of AMD3100 was also studied in coculture of peripheral blood mononuclear cells or CD4+ cell lines with chronically infected H9/IIIB cells. AMD3100 was found to inhibit both syncytium formation and apoptosis induction with 50% inhibitory concentrations ranging from 0.009 to 0.24 μg/ml, depending on the cell type. When compared to SDF-1α, AMD3100 showed higher inhibitory potency in all cell lines tested. Our data indicate that the bicyclam AMD3100 not only inhibits HIV replication but also efficiently blocks cell-surface-expressed HIV-1 envelope-induced apoptosis in uninfected cells.


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