Browsing by Subject "Receptor, Epidermal Growth Factor"

Now showing 1 - 8 of 8
  • Thumbnail Image
    ItemOpen Access
    Beta-arrestin-mediated beta1-adrenergic receptor transactivation of the EGFR confers cardioprotection.
    (J Clin Invest, 2007-09) Noma, Takahisa; Lemaire, Anthony; Naga Prasad, Sathyamangla V; Barki-Harrington, Liza; Tilley, Douglas G; Chen, Juhsien; Le Corvoisier, Philippe; Violin, Jonathan D; Wei, Huijun; Lefkowitz, Robert J; Rockman, Howard A
    Deleterious effects on the heart from chronic stimulation of beta-adrenergic receptors (betaARs), members of the 7 transmembrane receptor family, have classically been shown to result from Gs-dependent adenylyl cyclase activation. Here, we identify a new signaling mechanism using both in vitro and in vivo systems whereby beta-arrestins mediate beta1AR signaling to the EGFR. This beta-arrestin-dependent transactivation of the EGFR, which is independent of G protein activation, requires the G protein-coupled receptor kinases 5 and 6. In mice undergoing chronic sympathetic stimulation, this novel signaling pathway is shown to promote activation of cardioprotective pathways that counteract the effects of catecholamine toxicity. These findings suggest that drugs that act as classical antagonists for G protein signaling, but also stimulate signaling via beta-arrestin-mediated cytoprotective pathways, would represent a novel class of agents that could be developed for multiple members of the 7 transmembrane receptor family.
  • Thumbnail Image
    ItemOpen Access
    EGFR phosphorylation of DCBLD2 recruits TRAF6 and stimulates AKT-promoted tumorigenesis.
    (The Journal of clinical investigation, 2014-09) Feng, Haizhong; Lopez, Giselle Y; Kim, Chung Kwon; Alvarez, Angel; Duncan, Christopher G; Nishikawa, Ryo; Nagane, Motoo; Su, An-Jey A; Auron, Philip E; Hedberg, Matthew L; Wang, Lin; Raizer, Jeffery J; Kessler, John A; Parsa, Andrew T; Gao, Wei-Qiang; Kim, Sung-Hak; Minata, Mutsuko; Nakano, Ichiro; Grandis, Jennifer R; McLendon, Roger E; Bigner, Darell D; Lin, Hui-Kuan; Furnari, Frank B; Cavenee, Webster K; Hu, Bo; Yan, Hai; Cheng, Shi-Yuan
    Aberrant activation of EGFR in human cancers promotes tumorigenesis through stimulation of AKT signaling. Here, we determined that the discoidina neuropilin-like membrane protein DCBLD2 is upregulated in clinical specimens of glioblastomas and head and neck cancers (HNCs) and is required for EGFR-stimulated tumorigenesis. In multiple cancer cell lines, EGFR activated phosphorylation of tyrosine 750 (Y750) of DCBLD2, which is located within a recently identified binding motif for TNF receptor-associated factor 6 (TRAF6). Consequently, phosphorylation of DCBLD2 Y750 recruited TRAF6, leading to increased TRAF6 E3 ubiquitin ligase activity and subsequent activation of AKT, thereby enhancing EGFR-driven tumorigenesis. Moreover, evaluation of patient samples of gliomas and HNCs revealed an association among EGFR activation, DCBLD2 phosphorylation, and poor prognoses. Together, our findings uncover a pathway in which DCBLD2 functions as a signal relay for oncogenic EGFR signaling to promote tumorigenesis and suggest DCBLD2 and TRAF6 as potential therapeutic targets for human cancers that are associated with EGFR activation.
  • Thumbnail Image
    ItemOpen Access
    EGFRvIII-specific chimeric antigen receptor T cells migrate to and kill tumor deposits infiltrating the brain parenchyma in an invasive xenograft model of glioblastoma.
    (PLoS One, 2014) Miao, Hongsheng; Choi, Bryan D; Suryadevara, Carter M; Sanchez-Perez, Luis; Yang, Shicheng; De Leon, Gabriel; Sayour, Elias J; McLendon, Roger; Herndon, James E; Healy, Patrick; Archer, Gary E; Bigner, Darell D; Johnson, Laura A; Sampson, John H
    Glioblastoma (GBM) is the most common primary malignant brain tumor in adults and is uniformly lethal. T-cell-based immunotherapy offers a promising platform for treatment given its potential to specifically target tumor tissue while sparing the normal brain. However, the diffuse and infiltrative nature of these tumors in the brain parenchyma may pose an exceptional hurdle to successful immunotherapy in patients. Areas of invasive tumor are thought to reside behind an intact blood brain barrier, isolating them from effective immunosurveillance and thereby predisposing the development of "immunologically silent" tumor peninsulas. Therefore, it remains unclear if adoptively transferred T cells can migrate to and mediate regression in areas of invasive GBM. One barrier has been the lack of a preclinical mouse model that accurately recapitulates the growth patterns of human GBM in vivo. Here, we demonstrate that D-270 MG xenografts exhibit the classical features of GBM and produce the diffuse and invasive tumors seen in patients. Using this model, we designed experiments to assess whether T cells expressing third-generation chimeric antigen receptors (CARs) targeting the tumor-specific mutation of the epidermal growth factor receptor, EGFRvIII, would localize to and treat invasive intracerebral GBM. EGFRvIII-targeted CAR (EGFRvIII+ CAR) T cells demonstrated in vitro EGFRvIII antigen-specific recognition and reactivity to the D-270 MG cell line, which naturally expresses EGFRvIII. Moreover, when administered systemically, EGFRvIII+ CAR T cells localized to areas of invasive tumor, suppressed tumor growth, and enhanced survival of mice with established intracranial D-270 MG tumors. Together, these data demonstrate that systemically administered T cells are capable of migrating to the invasive edges of GBM to mediate antitumor efficacy and tumor regression.
  • Thumbnail Image
    ItemOpen Access
    Epidermal growth factor regulates hematopoietic regeneration after radiation injury.
    (Nat Med, 2013-03) Doan, Phuong L; Himburg, Heather A; Helms, Katherine; Russell, J Lauren; Fixsen, Emma; Quarmyne, Mamle; Harris, Jeffrey R; Deoliviera, Divino; Sullivan, Julie M; Chao, Nelson J; Kirsch, David G; Chute, John P
    The mechanisms that regulate hematopoietic stem cell (HSC) regeneration after myelosuppressive injury are not well understood. We identified epidermal growth factor (EGF) to be highly enriched in the bone marrow serum of mice bearing deletion of Bak and Bax in TIE2-expressing cells in Tie2Cre; Bak1(-/-); Bax(flox/-) mice. These mice showed radioprotection of the HSC pool and 100% survival after a lethal dose of total-body irradiation (TBI). Bone marrow HSCs from wild-type mice expressed functional EGF receptor (EGFR), and systemic administration of EGF promoted the recovery of the HSC pool in vivo and improved the survival of mice after TBI. Conversely, administration of erlotinib, an EGFR antagonist, decreased both HSC regeneration and the survival of mice after TBI. Mice with EGFR deficiency in VAV-expressing hematopoietic cells also had delayed recovery of bone marrow stem and progenitor cells after TBI. Mechanistically, EGF reduced radiation-induced apoptosis of HSCs and mediated this effect through repression of the proapoptotic protein PUMA. Our findings show that EGFR signaling regulates HSC regeneration after myelosuppressive injury.
  • Thumbnail Image
    ItemOpen Access
    LKB1 Loss induces characteristic patterns of gene expression in human tumors associated with NRF2 activation and attenuation of PI3K-AKT.
    (Journal of thoracic oncology : official publication of the International Association for the Study of Lung Cancer, 2014-06) Kaufman, Jacob M; Amann, Joseph M; Park, Kyungho; Arasada, Rajeswara Rao; Li, Haotian; Shyr, Yu; Carbone, David P
    Inactivation of serine/threonine kinase 11 (STK11 or LKB1) is common in lung cancer, and understanding the pathways and phenotypes altered as a consequence will aid the development of targeted therapeutic strategies. Gene and protein expressions in a murine model of v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (Kras)-mutant lung cancer have been studied to gain insight into the biology of these tumors. However, the molecular consequences of LKB1 loss in human lung cancer have not been fully characterized.We studied gene expression profiles associated with LKB1 loss in resected lung adenocarcinomas, non-small-cell lung cancer cell lines, and murine tumors. The biological significance of dysregulated genes was interpreted using gene set enrichment and transcription factor analyses and also by integration with somatic mutations and proteomic data.Loss of LKB1 is associated with consistent gene expression changes in resected human lung cancers and cell lines that differ substantially from the mouse model. Our analysis implicates novel biological features associated with LKB1 loss, including altered mitochondrial metabolism, activation of the nuclear respiratory factor 2 (NRF2) transcription factor by kelch-like ECH-associated protein 1 (KEAP1) mutations, and attenuation of the phosphatidylinositiol 3-kinase and v-akt murine thymoma viral oncogene homolog (PI3K/AKT) pathway. Furthermore, we derived a 16-gene classifier that accurately predicts LKB1 mutations and loss by nonmutational mechanisms. In vitro, transduction of LKB1 into LKB1-mutant cell lines results in attenuation of this signature.Loss of LKB1 defines a subset of lung adenocarcinomas associated with characteristic molecular phenotypes and distinctive gene expression features. Studying these effects may improve our understanding of the biology of these tumors and lead to the identification of targeted treatment strategies.
  • Thumbnail Image
    ItemOpen Access
    Modular nanotransporters: a multipurpose in vivo working platform for targeted drug delivery.
    (Int J Nanomedicine, 2012) Slastnikova, Tatiana A; Rosenkranz, Andrey A; Gulak, Pavel V; Schiffelers, Raymond M; Lupanova, Tatiana N; Khramtsov, Yuri V; Zalutsky, Michael R; Sobolev, Alexander S
    BACKGROUND: Modular nanotransporters (MNT) are recombinant multifunctional polypeptides created to exploit a cascade of cellular processes, initiated with membrane receptor recognition to deliver selective short-range and highly cytotoxic therapeutics to the cell nucleus. This research was designed for in vivo concept testing for this drug delivery platform using two modular nanotransporters, one targeted to the α-melanocyte-stimulating hormone (αMSH) receptor overexpressed on melanoma cells and the other to the epidermal growth factor (EGF) receptor overexpressed on several cancers, including glioblastoma, and head-and-neck and breast carcinoma cells. METHODS: In vivo targeting of the modular nanotransporter was determined by immuno-fluorescence confocal laser scanning microscopy and by accumulation of (125)I-labeled modular nanotransporters. The in vivo therapeutic effects of the modular nanotransporters were assessed by photodynamic therapy studies, given that the cytotoxicity of photosensitizers is critically dependent on their delivery to the cell nucleus. RESULTS: Immunohistochemical analyses of tumor and neighboring normal tissues of mice injected with multifunctional nanotransporters demonstrated preferential uptake in tumor tissue, particularly in cell nuclei. With (125)I-labeled MNT{αMSH}, optimal tumor:muscle and tumor:skin ratios of 8:1 and 9.8:1, respectively, were observed 3 hours after injection in B16-F1 melanoma-bearing mice. Treatment with bacteriochlorin p-MNT{αMSH} yielded 89%-98% tumor growth inhibition and a two-fold increase in survival for mice with B16-F1 and Cloudman S91 melanomas. Likewise, treatment of A431 human epidermoid carcinoma-bearing mice with chlorin e(6)- MNT{EGF} resulted in 94% tumor growth inhibition compared with free chlorin e(6), with 75% of animals surviving at 3 months compared with 0% and 20% for untreated and free chlorin e(6)-treated groups, respectively. CONCLUSION: The multifunctional nanotransporter approach provides a new in vivo functional platform for drug development that could, in principle, be applicable to any combination of cell surface receptor and agent (photosensitizers, oligonucleotides, radionuclides) requiring nuclear delivery to achieve maximum effectiveness.
  • Thumbnail Image
    ItemOpen Access
    Phosphorylation of cell surface receptors: a mechanism for regulating signal transduction pathways.
    (Endocr Rev, 1988-02) Sibley, DR; Benovic, JL; Caron, MG; Lefkowitz, RJ
  • Thumbnail Image
    ItemOpen Access
    Role of endocytosis in the activation of the extracellular signal-regulated kinase cascade by sequestering and nonsequestering G protein-coupled receptors.
    (Proc Natl Acad Sci U S A, 2000-02-15) Pierce, KL; Maudsley, S; Daaka, Y; Luttrell, LM; Lefkowitz, RJ
    Acting through a number of distinct pathways, many G protein-coupled receptors (GPCRs) activate the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) cascade. Recently, it has been shown that in some cases, clathrin-mediated endocytosis is required for GPCR activation of the ERK/MAPK cascade, whereas in others it is not. Accordingly, we compared ERK activation mediated by a GPCR that does not undergo agonist-stimulated endocytosis, the alpha(2A) adrenergic receptor (alpha(2A) AR), with ERK activation mediated by the beta(2) adrenergic receptor (beta(2) AR), which is endocytosed. Surprisingly, we found that in COS-7 cells, ERK activation by the alpha(2A) AR, like that mediated by both the beta(2) AR and the epidermal growth factor receptor (EGFR), is sensitive to mechanistically distinct inhibitors of clathrin-mediated endocytosis, including monodansylcadaverine, a mutant dynamin I, and a mutant beta-arrestin 1. Moreover, we determined that, as has been shown for many other GPCRs, both alpha(2A) and beta(2) AR-mediated ERK activation involves transactivation of the EGFR. Using confocal immunofluorescence microscopy, we found that stimulation of the beta(2) AR, the alpha(2A) AR, or the EGFR each results in internalization of a green fluorescent protein-tagged EGFR. Although beta(2) AR stimulation leads to redistribution of both the beta(2) AR and EGFR, activation of the alpha(2A) AR leads to redistribution of the EGFR but the alpha(2A) AR remains on the plasma membrane. These findings separate GPCR endocytosis from the requirement for clathrin-mediated endocytosis in EGFR transactivation-mediated ERK activation and suggest that it is the receptor tyrosine kinase or another downstream effector that must engage the endocytic machinery.