1
|
Mudumbi KC, Burns EA, Schodt DJ, Petrova ZO, Kiyatkin A, Kim LW, Mangiacapre EM, Ortiz-Caraveo I, Rivera Ortiz H, Hu C, Ashtekar KD, Lidke KA, Lidke DS, Lemmon MA. Distinct interactions stabilize EGFR dimers and higher-order oligomers in cell membranes. Cell Rep 2024; 43:113603. [PMID: 38117650 PMCID: PMC10835193 DOI: 10.1016/j.celrep.2023.113603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/23/2023] [Accepted: 12/05/2023] [Indexed: 12/22/2023] Open
Abstract
The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase with important roles in many cellular processes as well as in cancer and other diseases. EGF binding promotes EGFR dimerization and autophosphorylation through interactions that are well understood structurally. How these dimers relate to higher-order EGFR oligomers seen in cell membranes, however, remains unclear. Here, we used single-particle tracking (SPT) and Förster resonance energy transfer imaging to examine how each domain of EGFR contributes to receptor oligomerization and the rate of receptor diffusion in the cell membrane. Although the extracellular region of EGFR is sufficient to drive receptor dimerization, we find that the EGF-induced EGFR slowdown seen by SPT requires higher-order oligomerization-mediated in part by the intracellular tyrosine kinase domain when it adopts an active conformation. Our data thus provide important insight into the interactions required for higher-order EGFR assemblies involved in EGF signaling.
Collapse
Affiliation(s)
- Krishna C Mudumbi
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA.
| | - Eric A Burns
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA; Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - David J Schodt
- Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA; Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87106, USA
| | - Zaritza O Petrova
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Anatoly Kiyatkin
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Lucy W Kim
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Emma M Mangiacapre
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Irais Ortiz-Caraveo
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA; Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Hector Rivera Ortiz
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Chun Hu
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Kumar D Ashtekar
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Keith A Lidke
- Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA; Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87106, USA
| | - Diane S Lidke
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA; Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.
| | - Mark A Lemmon
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, Yale University West Campus, West Haven, CT 06516, USA.
| |
Collapse
|
2
|
Mudumbi KC, Burns EA, Schodt DJ, Petrova ZO, Kiyatkin A, Kim LW, Mangiacapre EM, Ortiz-Caraveo I, Ortiz HR, Hu C, Ashtekar KD, Lidke KA, Lidke DS, Lemmon MA. Distinct interactions stabilize EGFR dimers and higher-order oligomers in cell membranes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.10.536273. [PMID: 37090557 PMCID: PMC10120646 DOI: 10.1101/2023.04.10.536273] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase (RTK) with important roles in many cellular processes as well as cancer and other diseases. EGF binding promotes EGFR dimerization and autophosphorylation through interactions that are well understood structurally. However, it is not clear how these dimers relate to higher-order EGFR oligomers detected at the cell surface. We used single-particle tracking (SPT) and Förster resonance energy transfer (FRET) imaging to examine how each domain within EGFR contributes to receptor dimerization and the rate of its diffusion in the cell membrane. We show that the EGFR extracellular region is sufficient to drive receptor dimerization, but that the EGF-induced EGFR slow-down seen by SPT requires formation of higher order oligomers, mediated in part by the intracellular tyrosine kinase domain - but only when in its active conformation. Our data thus provide important insight into higher-order EGFR interactions required for EGF signaling.
Collapse
|
3
|
Srinivasan S, Regmi R, Lin X, Dreyer CA, Chen X, Quinn SD, He W, Coleman MA, Carraway KL, Zhang B, Schlau-Cohen GS. Ligand-induced transmembrane conformational coupling in monomeric EGFR. Nat Commun 2022; 13:3709. [PMID: 35794108 PMCID: PMC9259572 DOI: 10.1038/s41467-022-31299-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 06/13/2022] [Indexed: 01/26/2023] Open
Abstract
Single pass cell surface receptors regulate cellular processes by transmitting ligand-encoded signals across the plasma membrane via changes to their extracellular and intracellular conformations. This transmembrane signaling is generally initiated by ligand binding to the receptors in their monomeric form. While subsequent receptor-receptor interactions are established as key aspects of transmembrane signaling, the contribution of monomeric receptors has been challenging to isolate due to the complexity and ligand-dependence of these interactions. By combining membrane nanodiscs produced with cell-free expression, single-molecule Förster Resonance Energy Transfer measurements, and molecular dynamics simulations, we report that ligand binding induces intracellular conformational changes within monomeric, full-length epidermal growth factor receptor (EGFR). Our observations establish the existence of extracellular/intracellular conformational coupling within a single receptor molecule. We implicate a series of electrostatic interactions in the conformational coupling and find the coupling is inhibited by targeted therapeutics and mutations that also inhibit phosphorylation in cells. Collectively, these results introduce a facile mechanism to link the extracellular and intracellular regions through the single transmembrane helix of monomeric EGFR, and raise the possibility that intramolecular transmembrane conformational changes upon ligand binding are common to single-pass membrane proteins.
Collapse
Affiliation(s)
- Shwetha Srinivasan
- grid.116068.80000 0001 2341 2786Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
| | - Raju Regmi
- grid.116068.80000 0001 2341 2786Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA ,grid.4444.00000 0001 2112 9282Present Address: Institut Curie, CNRS, Laboratoire Physico Chimie Curie, Paris, France
| | - Xingcheng Lin
- grid.116068.80000 0001 2341 2786Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
| | - Courtney A. Dreyer
- grid.27860.3b0000 0004 1936 9684Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817 USA
| | - Xuyan Chen
- grid.116068.80000 0001 2341 2786Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
| | - Steven D. Quinn
- grid.116068.80000 0001 2341 2786Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA ,grid.5685.e0000 0004 1936 9668Present Address: Department of Physics, University of York, York, UK
| | - Wei He
- grid.250008.f0000 0001 2160 9702Lawrence Livermore National Laboratory, Livermore, CA 94550 USA
| | - Matthew A. Coleman
- grid.250008.f0000 0001 2160 9702Lawrence Livermore National Laboratory, Livermore, CA 94550 USA ,grid.27860.3b0000 0004 1936 9684Radiation Oncology, University of California Davis School of Medicine, Sacramento, CA 95817 USA
| | - Kermit L. Carraway
- grid.27860.3b0000 0004 1936 9684Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817 USA
| | - Bin Zhang
- grid.116068.80000 0001 2341 2786Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
| | - Gabriela S. Schlau-Cohen
- grid.116068.80000 0001 2341 2786Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
| |
Collapse
|
4
|
Devi M, Verma I, Pal SK. Distinct interfacial ordering of liquid crystals observed by protein-lipid interactions that enabled the label-free sensing of cytoplasmic protein at the liquid crystal-aqueous interface. Analyst 2021; 146:7152-7159. [PMID: 34734590 DOI: 10.1039/d1an01444g] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Interfaces formed between a lipid decorated liquid crystal (LC) film and an aqueous phase can mimic the bimolecular membrane where interfacially occurring biological phenomena (e.g., lipid-protein interactions, protein adsorption) can be visually monitored by observing the surface-sensitive orientations of LCs. The ordering behavior of LCs at different phospholipid-based LC interfaces (1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC) and lysophosphatidic acid (LPA)) were investigated to determine the sensing of an important cytoplasmic protein (juxtamembrane of epidermal growth factor receptor (JM-EGFR)). At both DLPC and LPA decorated interfaces, the LC adopts homeotropic ordering, causing a dark optical appearance under crossed polarizers. Interestingly, upon the introduction of JM-EGFR to these LC-aqueous interfaces, the homeotropic orientation of the LC changed to planar (bright optical appearance), suggesting the potential of the designed system for JM-EGFR sensing. The use of different lipid decorated LC-aqueous interfaces results in the emergence of distinct optical patterns. For example, at a DLPC laden interface, elongated bright domains are observed, whereas a uniform bright texture is observed on an LPA laden interface. The DLPC decorated LC-aqueous interface is found to be highly selective for the sensing of JM-EGFR with a detection limit in the nanomolar concentration region (∼ 50 nM). When compared to spectroscopic and other conventional techniques, the LC-based design is simpler, and it allows the simple and label-free optical sensing of JM-EGFR at fluidic interfaces.
Collapse
Affiliation(s)
- Manisha Devi
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali (IISERM), Knowledge City, Sector-81, SAS Nagar, Mohali 140306, India.
| | - Indu Verma
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali (IISERM), Knowledge City, Sector-81, SAS Nagar, Mohali 140306, India.
| | - Santanu Kumar Pal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali (IISERM), Knowledge City, Sector-81, SAS Nagar, Mohali 140306, India.
| |
Collapse
|
5
|
Structure-function analysis of oncogenic EGFR Kinase Domain Duplication reveals insights into activation and a potential approach for therapeutic targeting. Nat Commun 2021; 12:1382. [PMID: 33654076 PMCID: PMC7925532 DOI: 10.1038/s41467-021-21613-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 01/28/2021] [Indexed: 02/07/2023] Open
Abstract
Mechanistic understanding of oncogenic variants facilitates the development and optimization of treatment strategies. We recently identified in-frame, tandem duplication of EGFR exons 18 - 25, which causes EGFR Kinase Domain Duplication (EGFR-KDD). Here, we characterize the prevalence of ERBB family KDDs across multiple human cancers and evaluate the functional biochemistry of EGFR-KDD as it relates to pathogenesis and potential therapeutic intervention. We provide computational and experimental evidence that EGFR-KDD functions by forming asymmetric EGF-independent intra-molecular and EGF-dependent inter-molecular dimers. Time-resolved fluorescence microscopy and co-immunoprecipitation reveals EGFR-KDD can form ligand-dependent inter-molecular homo- and hetero-dimers/multimers. Furthermore, we show that inhibition of EGFR-KDD activity is maximally achieved by blocking both intra- and inter-molecular dimerization. Collectively, our findings define a previously unrecognized model of EGFR dimerization, providing important insights for the understanding of EGFR activation mechanisms and informing personalized treatment of patients with tumors harboring EGFR-KDD. Finally, we establish ERBB KDDs as recurrent oncogenic events in multiple cancers. An EGFR mutant with kinase domain duplication (EGFR-KDD) was previously identified in an index patient, but the functional and therapeutic implications remain unclear. Here, the authors show that KDD occurs in other ErbB receptors in multiple cancers, and characterize the mechanism and inhibition of EGFR-KDD.
Collapse
|
6
|
Sinclair JKL, Robertson WE, Mozumdar D, Quach K, Schepartz A. Allosteric Inhibition of the Epidermal Growth Factor Receptor. Biochemistry 2021; 60:500-512. [PMID: 33557518 DOI: 10.1021/acs.biochem.0c00978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We previously reported a family of hydrocarbon-stapled peptides designed to interact with the epidermal growth factor receptor (EGFR) juxtamembrane (JM) segment, blocking its ability to form a coiled coil dimer that is essential for receptor activation. These hydrocarbon-stapled peptides, most notably E1S, decreased the proliferation of cell lines that express wild-type EGFR (H2030 and A431) as well as those expressing the oncogenic mutants EGFR L858R (H3255) and L858R/T790M (H1975). Although our previous investigations provided evidence that E1S interacted with EGFR directly, the location and details of these interactions were not established. Here we apply biochemical and cross-linking mass spectrometry tools to better define the interactions between E1S and EGFR. Taken with previously reported structure-activity relationships, our results support a model in which E1S interacts simultaneously with both the JM and the C-lobe of the activator kinase, effectively displacing the JM of the receiver kinase. Our results also reveal potential interactions between E1S and the N-terminal region of the C-terminal tail. We propose a model in which E1S inhibits EGFR by both mimicking and inhibiting JM coiled coil formation. This model could be used to design novel, allosteric (and perhaps nonpeptidic) EGFR inhibitors.
Collapse
Affiliation(s)
- Julie K L Sinclair
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Wesley E Robertson
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520, United States
| | - Deepto Mozumdar
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.,Department of Chemistry, University of California, Berkeley, California 94705, United States
| | - Kim Quach
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Alanna Schepartz
- Department of Chemistry, University of California, Berkeley, California 94705, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, California 94705, United States
| |
Collapse
|
7
|
Mohr JD, Wagenknecht-Wiesner A, Holowka DA, Baird BA. Basic Amino Acids Within the Juxtamembrane Domain of the Epidermal Growth Factor Receptor Regulate Receptor Dimerization and Auto-phosphorylation. Protein J 2020; 39:476-486. [PMID: 33211253 DOI: 10.1007/s10930-020-09943-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2020] [Indexed: 11/30/2022]
Abstract
Epidermal growth factor receptor (EGFR) dysregulation is observed in many human cancers and is both a cause of oncogenesis and a target for chemotherapy. We previously showed that partial charge neutralization of the juxtamembrane (JX) region of EGFR via the EGFR R1-6 mutant construct induces constitutive receptor activation and transformation of NIH 3T3 cells, both from the plasma membrane and from the ER when combined with the ER-retaining L417H mutation (Bryant et al. in J Biol Chem 288:34930-34942, 2013). Here, we use chemical crosslinking and immunoblotting to show that these mutant constructs form constitutive, phosphorylated dimers in both the plasma membrane and the ER. Furthermore, we combine this electrostatic perturbation with conformationally-restricted receptor mutants to provide evidence that activation of EGFR R1-6 dimers requires functional coupling both between the EGFR extracellular dimerization arms and between intracellular tyrosine kinase domains. These findings provide evidence that the electrostatic charge of the JX region normally serves as a negative regulator of functional dimerization of EGFR.
Collapse
Affiliation(s)
- Jordan D Mohr
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA.,Graduate Field of Pharmacology, Cornell University, Ithaca, NY, USA
| | | | - David A Holowka
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Barbara A Baird
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA. .,Graduate Field of Pharmacology, Cornell University, Ithaca, NY, USA.
| |
Collapse
|
8
|
Molecular Architecture of a Network of Potential Intracellular EGFR Modulators: ARNO, CaM, Phospholipids, and the Juxtamembrane Segment. Structure 2020; 28:54-62.e5. [DOI: 10.1016/j.str.2019.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/09/2019] [Accepted: 10/31/2019] [Indexed: 01/24/2023]
|
9
|
Wang Z, Fan H, Hu X, Khamo J, Diao J, Zhang K, Pogorelov TV. Coaction of Electrostatic and Hydrophobic Interactions: Dynamic Constraints on Disordered TrkA Juxtamembrane Domain. J Phys Chem B 2019; 123:10709-10717. [PMID: 31751135 DOI: 10.1021/acs.jpcb.9b09352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the receptor tyrosine kinase family, conformational change induced by ligand binding is transmitted across the membrane via a single transmembrane helix and a flexible juxtamembrane domain (JMD). Membrane dynamics makes it challenging to study the structural mechanism of receptor activation experimentally. In this study, we employ all-atom molecular dynamics with highly mobile membrane mimetic (HMMM) to capture the native conformation of the JMD in tropomyosin receptor kinase A (TrkA). We find that phosphatidylinositol 4,5-bisphosphate (PIP2) lipids engage in stable binding with multiple basic residues. Anionic lipids can compete with salt bridges within the peptide and alter TrkA-JMD conformation. We discover three-residue insertion into the membrane and are able to either enhance or reduce the level of insertion through computationally-designed point mutations. The vesicle-binding experiment supports computational results and indicates that hydrophobic insertion is comparable to electrostatic binding for membrane anchoring. Biochemical assays on cell lines with mutated TrkA show that enhanced TrkA-JMD insertion promotes receptor degradation but does not affect the short-term signaling capacity. Our joint work points to a scenario where lipid headgroups and tails interact with basic and hydrophobic residues on disordered domain, respectively, to restrain flexibility and potentially modulate protein function.
Collapse
Affiliation(s)
| | | | - Xiao Hu
- Department of Cancer Biology , University of Cincinnati College of Medicine , Cincinnati , Ohio 45267 , United States
| | | | - Jiajie Diao
- Department of Cancer Biology , University of Cincinnati College of Medicine , Cincinnati , Ohio 45267 , United States
| | | | | |
Collapse
|
10
|
Li M, Yang J, Zhang L, Tu S, Zhou X, Tan Z, Zhou W, He Y, Li Y. A low-molecular-weight compound exerts anticancer activity against breast and lung cancers by disrupting EGFR/Eps8 complex formation. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2019; 38:211. [PMID: 31118055 PMCID: PMC6532146 DOI: 10.1186/s13046-019-1207-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 05/02/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND Epidermal growth factor receptor (EGFR) and epidermal growth factor receptor pathway substrate 8 (Eps8) have been widely reported to be expressed in various tumors. Eps8 is an important active kinase substrate of EGFR that directly binds to the juxtamembrane (JXM) domain of EGFR to form an EGFR/Eps8 complex. The EGFR/Eps8 complex is involved in regulating cancer progression and might be an ideal target for antitumor therapy. This study focused on the screening of small-molecule inhibitors that target the EGFR/Eps8 complex in breast cancer and non-small cell lung cancer (NSCLC). METHODS In silico virtual screening was used to identify small-molecule EGFR/Eps8 complex inhibitors. These compounds were screened for the inhibition of A549 and BT549 cell viability. The direct interaction between EGFR and Eps8 was measured using coimmunoprecipitation (CoIP) and JXM domain replacement assays. The antitumor effects of the inhibitors were analyzed in cancer cells and xenograft models. An acute toxicity study of EE02 was performed in a mouse model. In addition, the effect of the EE02 inhibitor on the protein expression of elements downstream of the EGFR/Eps8 complex was determined by western blotting and protein chip assays. RESULTS In this study of nearly 390,000 compounds screened by virtual database screening, the top 29 compounds were identified as candidate small-molecule EGFR/Eps8 complex inhibitors and evaluated by using cell-based assays. The compound EE02 was identified as the best match to our selection criteria. Further investigation demonstrated that EE02 directly bound to the JXM domain of EGFR and disrupted EGFR/Eps8 complex formation. EE02 selectively suppressed growth and induced apoptosis in EGFR-positive and Eps8-positive breast cancer and NSCLC cells. More importantly, the PI3K/Akt/mTOR and MAPK/Erk pathways downstream of the EGFR/Eps8 complex were suppressed by EE02. In addition, the suppressive effect of EE02 on tumor growth in vivo was comparable to that of erlotinib at the same dose. CONCLUSIONS We identified EE02 as an EGFR/Eps8 complex inhibitor that demonstrated promising antitumor effects in breast cancer and NSCLC. Our data suggest that the EGFR/Eps8 complex offers a novel cancer drug target.
Collapse
Affiliation(s)
- Meifang Li
- Department of Hematology, Zhujiang Hospital, Southern Medical University, No. 253 GongyeDadaoZhong, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Jilong Yang
- Department of Hematology, Zhujiang Hospital, Southern Medical University, No. 253 GongyeDadaoZhong, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Lenghe Zhang
- Department of Hematology, Zhujiang Hospital, Southern Medical University, No. 253 GongyeDadaoZhong, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Sanfang Tu
- Department of Hematology, Zhujiang Hospital, Southern Medical University, No. 253 GongyeDadaoZhong, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Xuan Zhou
- Department of Hematology, Zhujiang Hospital, Southern Medical University, No. 253 GongyeDadaoZhong, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Ze Tan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, People's Republic of China
| | - Weijun Zhou
- Department of Hematology, Zhujiang Hospital, Southern Medical University, No. 253 GongyeDadaoZhong, Guangzhou, Guangdong, 510282, People's Republic of China.
| | - Yanjie He
- Department of Hematology, Zhujiang Hospital, Southern Medical University, No. 253 GongyeDadaoZhong, Guangzhou, Guangdong, 510282, People's Republic of China.
| | - Yuhua Li
- Department of Hematology, Zhujiang Hospital, Southern Medical University, No. 253 GongyeDadaoZhong, Guangzhou, Guangdong, 510282, People's Republic of China.
| |
Collapse
|
11
|
Gerhart J, Thévenin AF, Bloch E, King KE, Thévenin D. Inhibiting Epidermal Growth Factor Receptor Dimerization and Signaling Through Targeted Delivery of a Juxtamembrane Domain Peptide Mimic. ACS Chem Biol 2018; 13:2623-2632. [PMID: 30133245 DOI: 10.1021/acschembio.8b00555] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Overexpression and deregulation of the epidermal growth factor receptor (EGFR) are implicated in multiple human cancers and therefore are a focus for the development of therapeutics. Current strategies aimed at inhibiting EGFR activity include monoclonal antibodies and tyrosine kinase inhibitors. However, activating mutations severely limit the efficacy of these therapeutics. There is thus a growing need for novel methods to inhibit EGFR. One promising approach involves blocking the association of the cytoplasmic juxtamembrane (JM) domain of EGFR, which has been shown to be essential for receptor dimerization and kinase function. Here, we aim to improve the selectivity and efficacy of an EGFR JM peptide mimic by utilizing the pH(low) insertion peptide (pHLIP), a unique molecule that can selectively target cancer cells solely based on their extracellular acidity. This delivery strategy potentially allows for more selective targeting to tumors than current methods and for anchoring the peptide mimic to the cytoplasmic leaflet of the plasma membrane, increasing its local concentration and thus efficacy. We show that the conjugated construct is capable of inhibiting EGFR phosphorylation and downstream signaling and of inducing concentration- and pH-dependent toxicity in cervical cancer cells. We envision that this approach could be expanded to the modulation of other single-span membrane receptors whose activity is mediated by JM domains.
Collapse
Affiliation(s)
- Janessa Gerhart
- Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, Pennsylvania 18015, United States
| | - Anastasia F. Thévenin
- Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, Pennsylvania 18015, United States
| | - Elizabeth Bloch
- Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, Pennsylvania 18015, United States
| | - Kelly E. King
- Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, Pennsylvania 18015, United States
| | - Damien Thévenin
- Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, Pennsylvania 18015, United States
| |
Collapse
|
12
|
Kjaergaard M, Kragelund BB. Functions of intrinsic disorder in transmembrane proteins. Cell Mol Life Sci 2017; 74:3205-3224. [PMID: 28601983 PMCID: PMC11107515 DOI: 10.1007/s00018-017-2562-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 06/01/2017] [Indexed: 12/19/2022]
Abstract
Intrinsic disorder is common in integral membrane proteins, particularly in the intracellular domains. Despite this observation, these domains are not always recognized as being disordered. In this review, we will discuss the biological functions of intrinsically disordered regions of membrane proteins, and address why the flexibility afforded by disorder is mechanistically important. Intrinsically disordered regions are present in many common classes of membrane proteins including ion channels and transporters; G-protein coupled receptors (GPCRs), receptor tyrosine kinases and cytokine receptors. The functions of the disordered regions are many and varied. We will discuss selected examples including: (1) Organization of receptors, kinases, phosphatases and second messenger sources into signaling complexes. (2) Modulation of the membrane-embedded domain function by ball-and-chain like mechanisms. (3) Trafficking of membrane proteins. (4) Transient membrane associations. (5) Post-translational modifications most notably phosphorylation and (6) disorder-linked isoform dependent function. We finish the review by discussing the future challenges facing the membrane protein community regarding protein disorder.
Collapse
Affiliation(s)
- Magnus Kjaergaard
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark.
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark.
- The Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus, Denmark.
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
13
|
Valley CC, Lewis AK, Sachs JN. Piecing it together: Unraveling the elusive structure-function relationship in single-pass membrane receptors. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1398-1416. [PMID: 28089689 DOI: 10.1016/j.bbamem.2017.01.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 12/17/2022]
Abstract
The challenge of crystallizing single-pass plasma membrane receptors has remained an obstacle to understanding the structural mechanisms that connect extracellular ligand binding to cytosolic activation. For example, the complex interplay between receptor oligomerization and conformational dynamics has been, historically, only inferred from static structures of isolated receptor domains. A fundamental challenge in the field of membrane receptor biology, then, has been to integrate experimentally observable dynamics of full-length receptors (e.g. diffusion and conformational flexibility) into static structural models of the disparate domains. In certain receptor families, e.g. the ErbB receptors, structures have led somewhat linearly to a putative model of activation. In other families, e.g. the tumor necrosis factor (TNF) receptors, structures have produced divergent hypothetical mechanisms of activation and transduction. Here, we discuss in detail these and other related receptors, with the goal of illuminating the current challenges and opportunities in building comprehensive models of single-pass receptor activation. The deepening understanding of these receptors has recently been accelerated by new experimental and computational tools that offer orthogonal perspectives on both structure and dynamics. As such, this review aims to contextualize those technological developments as we highlight the elegant and complex conformational communication between receptor domains. This article is part of a Special Issue entitled: Interactions between membrane receptors in cellular membranes edited by Kalina Hristova.
Collapse
Affiliation(s)
| | - Andrew K Lewis
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota, USA
| | - Jonathan N Sachs
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, USA.
| |
Collapse
|
14
|
Sphingosine 1-Phosphate Activation of EGFR As a Novel Target for Meningitic Escherichia coli Penetration of the Blood-Brain Barrier. PLoS Pathog 2016; 12:e1005926. [PMID: 27711202 PMCID: PMC5053521 DOI: 10.1371/journal.ppat.1005926] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 09/11/2016] [Indexed: 12/24/2022] Open
Abstract
Central nervous system (CNS) infection continues to be an important cause of mortality and morbidity, necessitating new approaches for investigating its pathogenesis, prevention and therapy. Escherichia coli is the most common Gram-negative bacillary organism causing meningitis, which develops following penetration of the blood-brain barrier (BBB). By chemical library screening, we identified epidermal growth factor receptor (EGFR) as a contributor to E. coli invasion of the BBB in vitro. Here, we obtained the direct evidence that CNS-infecting E. coli exploited sphingosine 1-phosphate (S1P) for EGFR activation in penetration of the BBB in vitro and in vivo. We found that S1P was upstream of EGFR and participated in EGFR activation through S1P receptor as well as through S1P-mediated up-regulation of EGFR-related ligand HB-EGF, and blockade of S1P function through targeting sphingosine kinase and S1P receptor inhibited EGFR activation, and also E. coli invasion of the BBB. We further found that both S1P and EGFR activations occurred in response to the same E. coli proteins (OmpA, FimH, NlpI), and that S1P and EGFR promoted E. coli invasion of the BBB by activating the downstream c-Src. These findings indicate that S1P and EGFR represent the novel host targets for meningitic E. coli penetration of the BBB, and counteracting such targets provide a novel approach for controlling E. coli meningitis in the era of increasing resistance to conventional antibiotics.
Collapse
|
15
|
Lelimousin M, Limongelli V, Sansom MSP. Conformational Changes in the Epidermal Growth Factor Receptor: Role of the Transmembrane Domain Investigated by Coarse-Grained MetaDynamics Free Energy Calculations. J Am Chem Soc 2016; 138:10611-22. [PMID: 27459426 PMCID: PMC5010359 DOI: 10.1021/jacs.6b05602] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
![]()
The epidermal growth
factor receptor (EGFR) is a dimeric membrane
protein that regulates key aspects of cellular function. Activation
of the EGFR is linked to changes in the conformation of the transmembrane
(TM) domain, brought about by changes in interactions of the TM helices
of the membrane lipid bilayer. Using an advanced computational approach
that combines Coarse-Grained molecular dynamics and well-tempered
MetaDynamics (CG-MetaD), we characterize the large-scale motions
of the TM helices, simulating multiple association and dissociation
events between the helices in membrane, thus leading to a free energy
landscape of the dimerization process. The lowest energy state of
the TM domain is a right-handed dimer structure in which the TM helices
interact through the N-terminal small-X3-small sequence
motif. In addition to this state, which is thought to correspond to
the active form of the receptor, we have identified further low-energy
states that allow us to integrate with a high level of detail a range
of previous experimental observations. These conformations may lead
to the active state via two possible activation pathways, which involve
pivoting and rotational motions of the helices, respectively. Molecular
dynamics also reveals correlation between the conformational changes
of the TM domains and of the intracellular juxtamembrane domains,
paving the way for a comprehensive understanding of EGFR signaling
at the cell membrane.
Collapse
Affiliation(s)
- Mickaël Lelimousin
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, U.K.,CERMAV, Université Grenoble Alpes and CNRS , BP 53, F-38041 Grenoble Cedex 9, France
| | - Vittorio Limongelli
- Università della Svizzera Italiana (USI), Faculty of Informatics, Institute of Computational Science - Center for Computational Medicine in Cardiology , via G. Buffi 13, CH-6900 Lugano, Switzerland.,Department of Pharmacy, University of Naples "Federico II" , via D. Montesano 49, I-80131 Naples, Italy
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, U.K
| |
Collapse
|
16
|
Sarabipour S, Hristova K. FGFR3 unliganded dimer stabilization by the juxtamembrane domain. J Mol Biol 2015; 427:1705-14. [PMID: 25688803 PMCID: PMC4380549 DOI: 10.1016/j.jmb.2015.02.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 01/12/2015] [Accepted: 02/11/2015] [Indexed: 11/22/2022]
Abstract
Receptor tyrosine kinases (RTKs) conduct biochemical signals upon dimerization in the membrane plane. While RTKs are generally known to be activated in response to ligand binding, many of these receptors are capable of forming unliganded dimers that are likely important intermediates in the signaling process. All 58 RTKs consist of an extracellular (EC) domain, a transmembrane (TM) domain, and an intracellular domain that includes a juxtamembrane (JM) sequence and a kinase domain. Here we investigate directly the effect of the JM domain on unliganded dimer stability of FGFR3, a receptor that is critically important for skeletal development. The data suggest that FGFR3 unliganded dimers are stabilized by receptor-receptor contacts that involve the JM domains. The contribution is significant, as it is similar in magnitude to the stabilizing contribution of a pathogenic mutation and the repulsive contribution of the EC domain. Furthermore, we show that the effects of the JM domain and a TM pathogenic mutation on unliganded FGFR3 dimer stability are additive. We observe that the JM-mediated dimer stabilization occurs when the JM domain is linked to FGFR3 TM domain and not simply anchored to the plasma membrane. These results point to a coordinated stabilization of the unliganded dimeric state of FGFR3 by its JM and TM domains via a mechanism that is distinctly different from the case of another well studied receptor, EGFR.
Collapse
Affiliation(s)
- Sarvenaz Sarabipour
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21212, USA
| | - Kalina Hristova
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21212, USA.
| |
Collapse
|
17
|
Kovacs E, Zorn JA, Huang Y, Barros T, Kuriyan J. A structural perspective on the regulation of the epidermal growth factor receptor. Annu Rev Biochem 2015; 84:739-64. [PMID: 25621509 DOI: 10.1146/annurev-biochem-060614-034402] [Citation(s) in RCA: 223] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase that plays a critical role in the pathogenesis of many cancers. The structure of intact forms of this receptor has yet to be determined, but intense investigations of fragments of the receptor have provided a detailed view of its activation mechanism, which we review here. Ligand binding converts the receptor to a dimeric form, in which contacts are restricted to the receptor itself, allowing heterodimerization of the four EGFR family members without direct ligand involvement. Activation of the receptor depends on the formation of an asymmetric dimer of kinase domains, in which one kinase domain allosterically activates the other. Coupling between the extracellular and intracellular domains may involve a switch between alternative crossings of the transmembrane helices, which form dimeric structures. We also discuss how receptor regulation is compromised by oncogenic mutations and the structural basis for negative cooperativity in ligand binding.
Collapse
|
18
|
Emerging concepts in the regulation of the EGF receptor and other receptor tyrosine kinases. Trends Biochem Sci 2014; 39:437-46. [DOI: 10.1016/j.tibs.2014.08.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 08/04/2014] [Accepted: 08/07/2014] [Indexed: 11/21/2022]
|
19
|
Sinclair JL, Schepartz A. Influence of macrocyclization on allosteric, juxtamembrane-derived, stapled peptide inhibitors of the epidermal growth factor receptor (EGFR). Org Lett 2014; 16:4916-9. [PMID: 25207804 PMCID: PMC4168776 DOI: 10.1021/ol502426b] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Indexed: 01/18/2023]
Abstract
The hydrocarbon-stapled peptide E1(S) allosterically inhibits the kinase activity of the epidermal growth factor receptor (EGFR) by blocking a distant but essential protein-protein interaction: a coiled coil formed from the juxtamembrane segment (JM) of each member of the dimeric partnership.1 Macrocyclization is not required for activity: the analogous unstapled (but alkene-bearing) peptide is equipotent in cell viability, immunoblot, and bipartite display experiments to detect coiled coil formation on the cell surface.
Collapse
Affiliation(s)
- Julie
K.-L. Sinclair
- Department of Chemistry and Department of
Molecular, Cellular and Developmental
Biology, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Alanna Schepartz
- Department of Chemistry and Department of
Molecular, Cellular and Developmental
Biology, Yale University, New Haven, Connecticut 06520-8107, United States
| |
Collapse
|
20
|
Abd Halim KB, Koldsø H, Sansom MSP. Interactions of the EGFR juxtamembrane domain with PIP2-containing lipid bilayers: Insights from multiscale molecular dynamics simulations. Biochim Biophys Acta Gen Subj 2014; 1850:1017-1025. [PMID: 25219456 PMCID: PMC4547087 DOI: 10.1016/j.bbagen.2014.09.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 09/02/2014] [Accepted: 09/03/2014] [Indexed: 12/13/2022]
Abstract
BACKGROUND The epidermal growth factor receptor (EGFR) is the best characterised member of the receptor tyrosine kinases, which play an important role in signalling across mammalian cell membranes. The EGFR juxtamembrane (JM) domain is involved in the mechanism of activation of the receptor, interacting with the anionic lipid phosphatidylinositol 4,5-bisphosphate (PIP2) in the intracellular leaflet of the cell membrane. METHODS Multiscale MD simulations were used to characterize PIP2-JM interactions. Simulations of the transmembrane helix plus JM region (TM-JM) dimer (PDB:2M20) in both PIP2-containing and PIP2-depleted lipid bilayer membranes revealed the interactions of the JM with PIP2 and other lipids. RESULTS PIP2 forms strong interactions with the basic residues in the R645-R647 motif of the JM domain resulting in clustering of PIP2 around the protein. This association of PIP2 and the JM domain aids stabilization of JM-A dimer away from the membrane. Mutation (R645N/R646N/R647N) or PIP2-depletion results in deformation of the JM-A dimer and changes in JM-membrane interactions. CONCLUSIONS These simulations support the proposal that the positively charged residues at the start of the JM-A domain stabilize the JM-A helices in an orientation away from the membrane surface through binding to PIP2, thus promoting a conformation corresponding to an asymmetric (i.e. activated) kinase. GENERAL SIGNIFICANCE This study indicates that MD simulations may be used to characterise JM/lipid interactions, thus helping to define their role in the mechanisms of receptor tyrosine kinases. This article is part of a Special Issue entitled Recent developments of molecular dynamics.
Collapse
Affiliation(s)
| | - Heidi Koldsø
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
| |
Collapse
|
21
|
Sinclair JL, Denton EV, Schepartz A. Inhibiting epidermal growth factor receptor at a distance. J Am Chem Soc 2014; 136:11232-5. [PMID: 25075632 PMCID: PMC4140499 DOI: 10.1021/ja504076t] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Indexed: 01/17/2023]
Abstract
The epidermal growth factor receptor (EGFR) tyrosine kinase is implicated in a large number of human cancers. Most EGFR inhibitors target the extracellular, growth factor-binding domain or the intracellular, ATP-binding domain. Here we describe molecules that inhibit the kinase activity of EGFR in a new way, by competing with formation of an essential intradimer coiled coil containing the juxtamembrane segment from each member of the receptor partnership. The most potent molecules we describe bind EGFR directly, decrease the proliferation of wild-type and mutant EGFR-dependent cells lines, inhibit phosphorylation of EGFR and downstream targets, and block coiled coil formation as judged by bipartite tetracysteine display. Potency is directly correlated with the ability to block coiled coil formation within full-length EGFR in cells.
Collapse
Affiliation(s)
- Julie
K.-L. Sinclair
- Department
of Chemistry and Department of Molecular, Cellular and Developmental
Biology, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Elizabeth V. Denton
- Department
of Chemistry and Department of Molecular, Cellular and Developmental
Biology, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Alanna Schepartz
- Department
of Chemistry and Department of Molecular, Cellular and Developmental
Biology, Yale University, New Haven, Connecticut 06520-8107, United States
| |
Collapse
|
22
|
Greenall SA, Donoghue JF, Gottardo NG, Johns TG, Adams TE. Glioma-specific Domain IV EGFR cysteine mutations promote ligand-induced covalent receptor dimerization and display enhanced sensitivity to dacomitinib in vivo. Oncogene 2014; 34:1658-66. [PMID: 24747966 DOI: 10.1038/onc.2014.106] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/03/2014] [Accepted: 03/12/2014] [Indexed: 01/15/2023]
Abstract
A feature of many gliomas is the amplification of the epidermal growth factor receptor (EGFR), resulting in its overexpression. Missense mutations or deletions within the extracellular domain are associated with this amplification and can lead to constitutive activation of the receptor, with the Domain I/II deletion, EGFRvIII, being the most common. These changes have also been associated with increased sensitivity to EGFR inhibition using small molecule inhibitors. We have expressed, in human glioma cells, EGFR containing four glioma-specific EGFR missense mutations within Domain IV (C620Y, C624F, C628Y and C636Y) to analyze their biological properties and sensitivity to EGFR inhibition. One of these mutants, C620Y, exhibited an enhanced basal phosphorylation, which was partially dependent on an EGFR-ligand autocrine loop. All Domain IV mutants responded equally as well as wildtype EGFR (wtEGFR) to ligand stimulation. Biochemical analysis revealed that a pre-formed, disulfide-bonded dimer associated with these mutations was underglycosylated, inactive and cytoplasmically retained. Ligand stimulation resulted in the formation of a tyrosine-phosphorylated, disulfide-bonded dimer for all Domain IV mutants but not for wtEGFR. Following treatment with the next-generation, irreversible pan-ErbB inhibitor dacomitinib, the C620Y, C624F and EGFRvIII mutants were inactivated, covalently dimerized and were retained in the cytoplasm, resulting in cell-surface receptor loss and, for C620Y and C624F, decreased binding of EGF. Dacomitinib treatment significantly reduced the in vivo growth of human glioma xenografts bearing C620Y, but not wtEGFR. Collectively, these data indicate that the unique biochemical traits of Domain IV EGFR cysteine mutants can be exploited for enhanced sensitivity to EGFR small molecule inhibitors, with potential clinical applications.
Collapse
Affiliation(s)
- S A Greenall
- 160;CSIRO Division of Materials Science and Engineering, Parkville, VIC, Australia
| | - J F Donoghue
- Oncogenic Signaling Laboratory and Brain Cancer Discovery Collaborative, Monash Institute of Medical Research, Clayton, VIC, Australia
| | - N G Gottardo
- Telethon Institute for Child Health Research and Brain Cancer Discovery Collaborative, Centre for Child Health Research, Subiaco, WA, Australia
| | - T G Johns
- Oncogenic Signaling Laboratory and Brain Cancer Discovery Collaborative, Monash Institute of Medical Research, Clayton, VIC, Australia
| | - T E Adams
- 160;CSIRO Division of Materials Science and Engineering, Parkville, VIC, Australia
| |
Collapse
|