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Carvalheiro M, Ferreira-Silva M, Holovanchuk D, Marinho HS, Moreira JN, Soares H, Corvo ML, Cruz MEM. Antagonist G-targeted liposomes for improved delivery of anticancer drugs in small cell lung carcinoma. Int J Pharm 2022; 612:121380. [PMID: 34915142 DOI: 10.1016/j.ijpharm.2021.121380] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 11/19/2021] [Accepted: 12/09/2021] [Indexed: 12/11/2022]
Abstract
Ligand-mediated targeted liposomes have the potential to increase therapeutic efficacy of anticancer drugs. This work aimed to evaluate the ability of antagonist G, a peptide targeting agent capable of blocking the action of multiple neuropeptides, to selectivity improve targeting and internalization of liposomal formulations (long circulating liposomes, LCL, and stabilized antisense lipid particles containing ionizable amino lipid, SALP) to H69 and H82 small cell lung carcinoma (SCLC) cell lines. Antagonist G-targeted LCL and SALP were prepared by two different methods (either by direct covalent linkage at activated PEG grafted onto the liposomal surface or by post-insertion of DSPE-PEG-antagonist-G-conjugates into pre-formed liposomes). Association of the liposomal formulations with target SCLC cells was studied by fluorescence microscopy using fluorescence-labelled liposomes and confirmed quantitatively with [3H]-CHE-labelled liposomes. An antisense oligodeoxynucleotide against the overexpressed oncogene c-myc(as(c-myc)) was efficiently loaded into SALP formulations, the encapsulation efficiency decreased due to the inclusion of the targeting ligand. Also, liposome size was affected by as(c-myc) physical chemical properties. The amount of antagonist G linked to the surface of the liposomal formulations was dependent on the coupling method and lipid composition used. Covalent attachment of antagonist G increased liposomes cellular association and internalization via receptor-mediated and clathrin-dependent endocytosis, as assessed in SCLC cell lines. Biodistribution studies in healthy mice revealed a preferential lung accumulation of antagonist G-targeted SALP as compared to the non-targeted counterpart. Lung levels of the former were up to 3-fold higher 24 h after administration, highlighting their potential to be used as delivery vectors for SCLC treatment.
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Affiliation(s)
- Manuela Carvalheiro
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Avenida Professor Gama Pinto, 1649-003 Lisboa, Portugal; Departamento de Farmácia, Farmacologia e Tecnologias em Saúde, Faculdade de Farmácia, Universidade de Lisboa, Avenida Professor Gama Pinto, 1649-003 Lisboa, Portugal
| | - Margarida Ferreira-Silva
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Avenida Professor Gama Pinto, 1649-003 Lisboa, Portugal; Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Denys Holovanchuk
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Avenida Professor Gama Pinto, 1649-003 Lisboa, Portugal; Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - H Susana Marinho
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal; Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - João Nuno Moreira
- CNC - Center for Neuroscience and Cell Biology, Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, Faculty of Medicine (Polo 1), Rua Larga, 3004-504 Coimbra, Portugal; UC - University of Coimbra, CIBB, Faculty of Pharmacy, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - Helena Soares
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal; Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, 1990-096 Lisboa, Portugal
| | - M Luisa Corvo
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Avenida Professor Gama Pinto, 1649-003 Lisboa, Portugal; Departamento de Farmácia, Farmacologia e Tecnologias em Saúde, Faculdade de Farmácia, Universidade de Lisboa, Avenida Professor Gama Pinto, 1649-003 Lisboa, Portugal.
| | - Maria Eugénia M Cruz
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Avenida Professor Gama Pinto, 1649-003 Lisboa, Portugal
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Offerman SC, Kadirvel M, Abusara OH, Bryant JL, Telfer BA, Brown G, Freeman S, White A, Williams KJ, Aojula HS. N-tert-Prenylation of the indole ring improves the cytotoxicity of a short antagonist G analogue against small cell lung cancer. MEDCHEMCOMM 2017; 8:551-558. [PMID: 30108771 PMCID: PMC6072501 DOI: 10.1039/c6md00691d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/10/2017] [Indexed: 11/21/2022]
Abstract
Natural prenylated indoles have been proposed as potential anticancer agents. To exploit this discovery for developing new peptide therapeutics, we report the first studies whereby incorporation of prenylated indoles into primary sequences has been achieved. We developed a route to synthesise Nα-Fmoc-protected tryptophan derivatives in which the prenyl group is linked to the N-indole core, using Pd(ii)-mediated C-H functionalisation of 2-methyl-2-butene. Based on the Substance P antagonist G (SPG), a well-known Small Cell Lung Cancer (SCLC) anticancer agent, we designed a new penta-peptide sequence to include a prenyl moiety on one of the tryptophan residues. The N-tert-prenylated tryptophan analogue was assembled into the pentameric peptide using standard solid phase peptide synthesis or liquid phase synthesis by fragment coupling. In vitro screening showed that the N-tert-prenylation of the indole ring on the tryptophan residue located near the C-terminal of the penta-peptide enhanced the cytotoxicity against H69 (IC50 = 2.84 ± 0.14 μM) and DMS79 (IC50 = 4.37 ± 0.44 μM) SCLC cell lines when compared with the unmodified penta-peptide (H69, IC50 = 30.74 ± 0.30 μM and DMS79, IC50 = 23.00 ± 2.07 μM) or the parent SPG sequence (IC50 > 30 μM, both cell lines). SCLC almost invariably relapses with therapy-resistant disease. The DMS79 cell line was established from a patient following treatment with a number of chemotherapeutics (cytoxan, vincristine and methotrexate) and radiation therapy. Treating DMS79 tumour-bearing nude mice provided a human xenograft model of drug resistance to test the efficacy of the prenylated peptide. A low dose (1.5 mg kg-1) of the prenylated peptide was found to reduce tumour growth by ∼30% (P < 0.05) at day 7, relative to the control group receiving vehicle only. We conclude that the availability of the Fmoc-Trp(N-tert-prenyl)-OH amino acid facilitates the synthesis of prenylated-tryptophan-containing peptides to explore their therapeutic potential.
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Affiliation(s)
- Shaun C Offerman
- Division of Pharmacy and Optometry , School of Health Sciences , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK .
| | - Manikandan Kadirvel
- CRUK-EPSRC Cancer Imaging Centre in Cambridge and Manchester , Manchester , M20 3LJ , UK
| | - Osama H Abusara
- Division of Pharmacy and Optometry , School of Health Sciences , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK .
| | - Jennifer L Bryant
- Division of Pharmacy and Optometry , School of Health Sciences , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK .
| | - Brian A Telfer
- Division of Pharmacy and Optometry , School of Health Sciences , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK .
| | - Gavin Brown
- CRUK-EPSRC Cancer Imaging Centre in Cambridge and Manchester , Manchester , M20 3LJ , UK
| | - Sally Freeman
- Division of Pharmacy and Optometry , School of Health Sciences , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK .
| | - Anne White
- Division of Diabetes, Endocrinology & Gastroenterology , School of Medical Sciences , Faculty of Biology, Medicine, & Health , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK
| | - Kaye J Williams
- Division of Pharmacy and Optometry , School of Health Sciences , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK .
- CRUK-EPSRC Cancer Imaging Centre in Cambridge and Manchester , Manchester , M20 3LJ , UK
| | - Harmesh S Aojula
- Division of Pharmacy and Optometry , School of Health Sciences , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK .
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Gao H, Liu J, Song N. [Application of target peptide in siRNA delivery
for the research of lung cancer therapy]. ZHONGGUO FEI AI ZA ZHI = CHINESE JOURNAL OF LUNG CANCER 2014; 17:674-8. [PMID: 25248709 PMCID: PMC6000512 DOI: 10.3779/j.issn.1009-3419.2014.09.06] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
肺癌被认为是全球发病率最高的一种恶性肿瘤,其对化疗药物不敏感且易产生耐药性,因此增强肺癌药物治疗效果是近年来研究的热点。siRNA是一种小RNA分子,可以沉默与之互补的目标mRNA,是一种基因治疗手段。靶向肽是一类小分子多肽,它可以与siRNA联合使用,利用其与肿瘤表面物质特异性结合发挥靶向作用。联合靶向肽的特异性和siRNA的治疗作用,增加siRNA在靶点位置的聚集,增强沉默效果,可以提高肺癌对药物的敏感性并降低耐药作用,进而增强肺癌治疗效果,为肺癌的靶向治疗提供新的方向和策略。本文将对靶向肽在递送siRNA进行肺癌治疗研究中的应用作一简要综述。
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Affiliation(s)
- Honglin Gao
- Department of Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine,
Peking Union Medical College, Chinese Academy of Medical Sciences, Tianjin 300192, China
| | - Jianfeng Liu
- Department of Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine,
Peking Union Medical College, Chinese Academy of Medical Sciences, Tianjin 300192, China
| | - Naling Song
- Department of Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine,
Peking Union Medical College, Chinese Academy of Medical Sciences, Tianjin 300192, China
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G Protein-Coupled Receptors in cancer: biochemical interactions and drug design. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 115:143-73. [PMID: 23415094 DOI: 10.1016/b978-0-12-394587-7.00004-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
G Protein-Coupled Receptors (GPCRs) share the same topology made of seven-transmembrane segments and represent the largest family of membrane receptors. Initially associated with signal transduction in differentiated cells, GPCRs and heterotrimeric G proteins were shown to behave as proto-oncogenes whose overexpression or activating mutations confer transforming properties. The first part of this review focuses on the link between biochemical interactions of a GPCR with other receptors, such as dimerization or multiprotein complexes, and their oncogenic properties. Alteration of these interactions or deregulation of transduction cascades can promote uncontrolled cell proliferation or cell transformation that leads to tumorigenicity and malignancy. The second part concerns the design of drugs specifically targeting these complex interactions and their promise in cancer therapy.
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Santos AO, da Silva LCG, Bimbo LM, de Lima MCP, Simões S, Moreira JN. Design of peptide-targeted liposomes containing nucleic acids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1798:433-41. [PMID: 20004174 DOI: 10.1016/j.bbamem.2009.12.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 11/08/2009] [Accepted: 12/01/2009] [Indexed: 11/15/2022]
Abstract
Anticancer systemic gene silencing therapy has been so far limited by the inexistence of adequate carrier systems that ultimately provide an efficient intracellular delivery into target tumor cells. In this respect, one promising strategy involves the covalent attachment of internalizing-targeting ligands at the extremity of PEG chains grafted onto liposomes. Therefore, the present work aims at designing targeted liposomes containing nucleic acids, with small size, high encapsulation efficiency and able to be actively internalized by SCLC cells, using a hexapeptide (antagonist G) as a targeting ligand. For this purpose, the effect of the liposomal preparation method, loading material (ODN versus siRNA) and peptide-coupling procedure (direct coupling versus post-insertion) on each of the above-mentioned parameters was assessed. Post-insertion of DSPE-PEG-antagonist G conjugates into preformed liposomes herein named as stabilized lipid particles, resulted in targeted vesicles with a mean size of about 130 nm, encapsulation efficiency close to 100%, and a loading capacity of approximately 5 nmol siRNA/mumol of total lipid. In addition, the developed targeted vesicles showed increased internalization in SCLC cells, as well as in other tumor cells and HMEC-1 microvascular endothelial cells. The improved cellular association, however, did not correlate with enhanced downregulation of the target protein (Bcl-2) in SCLC cells. These results indicate that additional improvements need to be performed in the future, namely by ameliorating the access of the nucleic acids to the cytoplasm of the tumor cells following receptor-mediated endocytosis.
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Affiliation(s)
- Adriana O Santos
- Laboratory of Pharmaceutical Technology, University of Coimbra, Portugal
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MacKinnon AC, Tufail-Hanif U, Wheatley M, Rossi AG, Haslett C, Seckl M, Sethi T. Targeting V1A-vasopressin receptors with [Arg6, D-Trp7,9, NmePhe8]-substance P (6-11) identifies a strategy to develop novel anti-cancer therapies. Br J Pharmacol 2009; 156:36-47. [PMID: 19133990 DOI: 10.1111/j.1476-5381.2008.00003.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE The anti-cancer agent [Arg(6), D-Trp(7,9), N(me)Phe(8)]-substance P (6-11) (SP-G) modulates gastrin releasing peptide (GRP) and arginine vasopressin signalling in small cell lung cancer cells leading to growth arrest and apoptosis. We have shown that SP-G acts as a biased agonist at GRP receptors. This work examines the hypothesis that SP-G acts as a biased agonist at the V(1A) vasopressin receptor. EXPERIMENTAL APPROACH The human V(1A) receptor was expressed in CHO-K1 cells. Extracellular regulated kinase (ERK) activation and intracellular Ca(2+) were measured using activation state-specific antibodies and Fura-2-AM respectively. The effect of SP-G on tumourigenicity was assessed by colony assay. KEY RESULTS In V(1A) receptor expressing cells, SP-G caused a sustained activation of ERK via a stimulation of V(1A) receptor coupling to G(i). Inhibition of G(i) with Pertussis toxin attenuated the inhibition by SP-G of the growth of CHO-K1 cells stably expressing the V(1A) receptor. Chimeric V(1A) receptors containing the second or third intracellular loop of the V(2) receptor were capable of binding vasopressin and SP-G but had altered ability to activate phospholipase C (PLC) and ERK. The second intracellular loop of the V(1A) receptor was essential for vasopressin-stimulated PLC and ERK activation but not for SP-G-induced ERK activation. CONCLUSIONS AND IMPLICATIONS This work provides mechanistic insight, for biased agonists at V(1A) receptors and highlights a potential role for such agents as anti-cancer agents.
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Affiliation(s)
- Alison C MacKinnon
- University of Edinburgh, Centre for Inflammation Research, Queen's Medical Research Institute, Edinburgh, UK
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Springer J, Groneberg DA, Dinh QT, Quarcoo D, Hamelmann E, Braun-Dullaeus RC, Geppetti P, Anker SD, Fischer A. Neurokinin-1 receptor activation induces reactive oxygen species and epithelial damage in allergic airway inflammation. Clin Exp Allergy 2007; 37:1788-97. [PMID: 17941913 DOI: 10.1111/j.1365-2222.2007.02851.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND An induction of reactive oxygen species (ROS) is characteristic for inflammation but the exact pathways have not been identified for allergic airway diseases so far. OBJECTIVE The aim of this study was to characterize the role of the tachykinin NK-1 receptor on ROS production during allergen challenge and subsequent inflammation and remodelling. METHODS Precision-cut lung slices of ovalbumin (OVA)-sensitized mice were cultivated and ROS-generation in response to OVA challenge (10 microg/mL) was examined by the 2',7'-dichloroflourescein-diacetate method. Long-term ROS effects on epithelial proliferation were investigated by 5-bromo-2'-deoxyuridine incorporation (72 h). In vivo, the results were validated in OVA-sensitized animals which were treated intra-nasally with either placebo, the tachykinin neurokinin 1 (NK-1) receptor antagonist SR 140333 or the anti-oxidant N-acetylcystein (NAC) before allergen challenge. Inflammatory infiltration and remodelling were assessed 48 h after allergen challenge. RESULTS ROS generation was increased by 3.7-fold, which was inhibited by SR 140333. [Sar(9),Met(11)(O(2))]-Substance P (5 nM) caused a tachykinin NK-1 receptor-dependent fourfold increase in ROS generation. Epithelial proliferation was decreased by 68% by incubation with [Sar(9),Met(11)(O(2))]-SP over 72 h. In-vivo, treatment with SR 140333 and NAC reduced epithelial damage (91.4% and 76.8% vs. placebo, respectively, P<0.01) and goblet cell hyperplasia (67.4% and 50.1% vs. placebo, respectively, P<0.05), and decreased inflammatory cell influx (65.3% and 45.3% vs. placebo, respectively, P<0.01). CONCLUSION Allergen challenge induces ROS in a tachykinin NK-1 receptor-dependent manner. Inhibition of the tachykinin NK-1 receptor reduces epithelial damage and subsequent remodelling in vivo. Therefore, patients may possibly benefit from treatment regime that includes radical scavengers or tachykinin NK-1 receptor antagonists.
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Affiliation(s)
- J Springer
- Department of Cardiology, Division of Applied Cachexia Research, Charité Medical School, Berlin, Germany.
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Roelle S, Grosse R, Buech T, Chubanov V, Gudermann T. Essential role of Pyk2 and Src kinase activation in neuropeptide-induced proliferation of small cell lung cancer cells. Oncogene 2007; 27:1737-48. [PMID: 17906699 DOI: 10.1038/sj.onc.1210819] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Neuropeptide hormones like bombesin/gastrin-releasing peptide, galanin or bradykinin, acting via auto and paracrine growth loops, represent the principal mitogens of small cell lung cancer (SCLC). These mitogenic neuropeptides activate G(q/11)-coupled receptors which stimulate phospholipase Cbeta activity, followed by rises of the intracellular calcium concentration ([Ca2+](i)) and activation of protein kinase C (PKC). We report here that proline-rich tyrosine kinase Pyk2 is highly expressed in SCLC cells and provides a functional link between neuropeptide-induced increases in [Ca2+](i) and tumor cell proliferation. Activation of Pyk2 and its association with Src kinases critically depends on the elevation of [Ca2+](i), but is independent of PKC. Src kinase activities are crucial for neuropeptide-mediated GTP-loading of Ras and activation of extracellular signal-regulated kinases in SCLC cells. Pyk2 and Src kinases essentially contribute to anchorage-independent proliferation of SCLC cells. Inhibition of either Pyk2 or Src kinases by lentiviral RNAi or pharmacological inhibition with PP2, respectively, attenuated basal and neuropeptide-elicited survival and proliferation of SCLC cells in liquid culture and in soft agar. Thus, neuropeptides stimulate anchorage-independent survival and proliferation of SCLC cells via pathways involving Pyk2 and Src kinases. Therefore, Ca2+-induced Pyk2/Src complex formation may be a rewarding molecular target for novel therapeutic strategies in SCLC cells.
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Affiliation(s)
- S Roelle
- 1Institut für Pharmakologie und Toxikologie, Philipps-Universität Marburg, Marburg, Germany
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Keire DA, Kumar M, Hu W, Sinnett-Smith J, Rozengurt E. The lipid-associated 3D structure of SPA, a broad-spectrum neuropeptide antagonist with anticancer properties. Biophys J 2006; 91:4478-89. [PMID: 16997863 PMCID: PMC1779918 DOI: 10.1529/biophysj.106.089292] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
[D-Arg(1), D-Trp(5,7,9), Leu(11)] substance P (SPA) belongs to a family of peptides including antagonist G and SpD that act as broad-spectrum neuropeptide antagonists at several peripheral receptors. The lipid-induced structure of these peptides may be important for the receptor interactions of these analogs. Thus we describe the tertiary structure of SPA in the presence of sodium dodecylsulfate micelles at pH 5.0, and 25 degrees C as determined from two-dimensional (1)H-NMR data recorded at 500 MHz. The resulting three-dimensional structure can be generally described as two type IV nonstandard turns around Arg(1)*, Pro(2), Lys(3), and Pro(4) and Gln(6), Trp(7)*, Phe(8), and Trp(9)* residues, respectively, inserted into the interfacial region of the micelles (the asterisks denote D-form amino acid). These turns juxtapose the N- and C-termini of SPA and may form the basis of this peptide's unique ability to inhibit peptide receptor interactions at multiple receptor types.
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Affiliation(s)
- David A Keire
- CURE Digestive Diseases Research Center, VA Greater Los Angeles Healthcare System, Los Angeles, CA 90073, USA.
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Karlsson K, Sharma H, Nyberg F. Chromatographic characterization of substance P endopeptidase in the rat brain reveals affected enzyme activity following heat stress. Biomed Chromatogr 2006; 20:77-82. [PMID: 15954166 DOI: 10.1002/bmc.531] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This paper describes a study of substance P endopeptidase (SPE)-like activity in various regions of the brain from male rats subjected to heat stress (HS). The enzyme activity was found to be affected in several brain areas including cerebellum, cerebral cortex, hippocampus, hypothalamus[sol ]thalamus and the spinal cord following HS. Significant increases in SPE activity were observed in, for example, hippocampus and the spinal cord. SPE-containing extracts from hippocampus were pooled and subsequently purified by size exclusion chromatography (using a Superdex 75 HR column) and by anion-exchange chromatography (using Resource Q column). The gel permeation chromatography separated the SPE-like activity into two fractions, one of which was suggested to be identical to neutral endopeptidase owing to its molecular size and inhibitory profile. The other active enzyme fraction behaved in conformity with SPE, previously identified in human cerebrospinal fluid. The activity of the purified fraction of these two enzymes was found to be increased (27%) in HS-treated animals.
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Affiliation(s)
- Krister Karlsson
- Uppsala University, Division of Biological Research on Drug Dependence, Department of Pharmaceutical Bioscience, Faculty of Pharmacy, Uppsala University, PO Box 591, S-751 24, Uppsala, Sweden.
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Springer J, Pleimes D, Scholz FR, Fischer A. Substance P mediates AP-1 induction in A549 cells via reactive oxygen species. ACTA ACUST UNITED AC 2005; 124:99-103. [PMID: 15544846 DOI: 10.1016/j.regpep.2004.07.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2004] [Revised: 06/21/2004] [Accepted: 07/01/2004] [Indexed: 10/26/2022]
Abstract
A common feature in asthma is the induction of reactive oxygen species (ROS) and the AP-1 transcription factor during the inflammatory process. AP-1 induction leads to an increased expression of pro-inflammatory cytokines. Also, higher levels of the pro-inflammatory neuropeptide substance P (SP) have been reported in bronchoalveolar-lavage fluid of asthmatics. Here, the role of SP on ROS induction and the downstream activation of AP-1 in A549 airway epithelial cells was investigated by dichloroflourescein-diacetate method and reporter gene assays. The SP-mediated AP-1 induction was dependent on extracellular calcium and ROS. The likely source of ROS are the mitochondria as rotenone inhibited AP-1 induction and the p47phox subunit of the NADPH oxidase complex, responsible for ROS generation in phagocytotic cells, was not expressed in A549 cells assayed by RT-PCR. This is consistent with results obtained from cells of murine bronchial epithelium, isolated by laser capture microdissection. In summary, this study provides evidence for an SP-mediated induction of AP-1, which may contribute to the expression of pro-inflammatory cytokines.
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Affiliation(s)
- Jochen Springer
- Division of Allergy Research, Department Pediatric Pneumology and Immunology, Charité Medical School, Berlin, Germany.
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12
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MacKinnon AC, Tufail-Hanif U, Lucas CD, Jodrell D, Haslett C, Sethi T. Expression of V1A and GRP receptors leads to cellular transformation and increased sensitivity to substance-P analogue-induced growth inhibition. Br J Cancer 2005; 92:522-31. [PMID: 15685238 PMCID: PMC2362091 DOI: 10.1038/sj.bjc.6602366] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Small-cell lung cancer (SCLC) is a particularly aggressive cancer, which metastasises early. Despite initial sensitivity to radio- and chemo-therapy, it invariably relapses, so that the 2-year survival remains less than 5%. Neuropeptides particularly arginine vasopressin (AVP) and gastrin-releasing peptide (GRP) act as autocrine and paracrine growth factors and the expression of these and their receptors are a hallmark of the disease. Substance-P analogues including [D-Arg1,D-Phe5,D-Trp7,9,Leu11]-substance-P (SP-D) and [Arg6,D-Trp7,9,NmePhe8]-substance-P (6-11) (SP-G) inhibit the growth of SCLC cells by modulating neuropeptide signalling. We show that GRP and V1A receptors expression leads to the development of a transformed phenotype. Addition of neuropeptide provides some protection from etoposide-induced cytotoxicity. Receptor expression also leads to an increased sensitivity to substance-P analogue-induced growth inhibition. We show that SP-D and SP-G act as biased agonists at GRP and V1A receptors causing blockade of Gq-mediated Ca2+ release while directing signalling to activate ERK via a pertussis toxin-sensitive pathway. This is the first description of biased agonism at V1A receptors. This unique pharmacology governs the antiproliferative properties of these agents and highlights their potential therapeutic potential for the treatment of SCLC and particularly in tumours, which have developed resistance to chemotherapy.
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Affiliation(s)
- A C MacKinnon
- Centre for Inflammation Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - U Tufail-Hanif
- Centre for Inflammation Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - C D Lucas
- Centre for Inflammation Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - D Jodrell
- Cancer Research UK, Medical Oncology Unit, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK
| | - C Haslett
- Centre for Inflammation Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - T Sethi
- Centre for Inflammation Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
- Centre for Inflammation Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK. E-mail:
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13
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Djanani A, Kaneider NC, Sturn D, Wiedermann CJ. Agonist function of the neurokinin receptor antagonist, [D-Arg1,D-Phe5,D-Trp7,9,Leu11]substance P, in monocytes. REGULATORY PEPTIDES 2003; 115:123-9. [PMID: 12972327 DOI: 10.1016/s0167-0115(03)00148-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
G-protein-coupled bombesin receptors are capable of signaling through the G(i) protein even when receptor-coupling to G(q) is blocked by [D-Arg1,D-Phe5,D-Trp7,9,Leu11]substance P (SpD), a neurokinin-1 receptor antagonist and "biased" agonist to bombesin receptors. As bombesin is a monocyte and tumor cell attractant, we were interested in the effects of SpD on cell migration. Chemotaxis of monocytes was tested in micropore filter assays. SpD was a dose-dependent agonist in monocyte migration and was not inhibited by antagonists to neurokinin-1 or -2 receptors. SpD failed to inhibit chemotaxis toward bombesin, suggesting that inhibition of bombesin receptor coupling to G(q) with SpD does not impair migratory responses elicited by bombesin. As pertussis toxin inhibited migration, coupling of receptors to G(i) may signal migration. Chemotaxis toward SpD was inhibited by bombesin receptor antagonists as well as by blocking signaling enzymes downstream of G(q) (phospholipase-3 and protein kinase C with wortmannin and bisindolylmaleimide, respectively), suggesting transactivation of G(q)-mediated chemotaxis signaling by SpD via bombesin receptors. Protein kinase C that induces sphingosine kinase activation and production of sphingosine-1-phosphate, which may lead to G(q)-dependent chemoattraction, was involved in SpD-dependent migration. Inhibition of sphingosine-1-phosphate production with dimethylsphingosine inhibited monocyte migration toward SpD. Data suggest that SpD induces migration in monocytes and signaling events involving activation of sphingosine kinase in a G(i) protein- and protein kinase C-dependent fashion. "Biased" agonism of SpD at bombesin receptors may affect normal and tumor cell migration.
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Affiliation(s)
- Angela Djanani
- Department of Internal Medicine, Division of General Internal Medicine, University of Innsbruck, Anichstrasse 35, A-6020, Innsbruck, Austria
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14
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Waters CM, MacKinnon AC, Cummings J, Tufail-Hanif U, Jodrell D, Haslett C, Sethi T. Increased gastrin-releasing peptide (GRP) receptor expression in tumour cells confers sensitivity to [Arg6,D-Trp7,9,NmePhe8]-substance P (6-11)-induced growth inhibition. Br J Cancer 2003; 88:1808-16. [PMID: 12771999 PMCID: PMC2377129 DOI: 10.1038/sj.bjc.6600957] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
[Arg(6),D-Trp(7,9),N(me)Phe(8)]-substance P (6-11) (SP-G) is a novel anticancer agent that has recently completed phase I clinical trials. SP-G inhibits mitogenic neuropeptide signal transduction and small cell lung cancer (SCLC) cell growth in vitro and in vivo. Using the SCLC cell line series GLC14, 16 and 19, derived from a single patient during the clinical course of their disease and the development of chemoresistance, it is shown that there was an increase in responsiveness to neuropeptides. This was paralleled by an increased sensitivity to SP-G. In a selected panel of tumour cell lines (SCLC, non-SCLC, ovarian, colorectal and pancreatic), the expression of the mitogenic neuropeptide receptors for vasopressin, gastrin-releasing peptide (GRP), bradykinin and gastrin was examined, and their sensitivity to SP-G tested in vitro and in vivo. The tumour cell lines displayed a range of sensitivity to SP-G (IC(50) values from 10.5 to 119 microM). The expression of the GRP receptor measured by reverse transcriptase-polymerase chain reaction, correlated significantly with growth inhibition by SP-G. Moreover, introduction of the GRP receptor into rat-1A fibroblasts markedly increased their sensitivity to SP-G. The measurement of receptor expression from biopsy samples by polymerase chain reaction could provide a suitable diagnostic test to predict efficacy to SP-G clinically. This strategy would be of potential benefit in neuropeptide receptor-expressing tumours in addition to SCLC, and in tumours that are relatively resistant to conventional chemotherapy.
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MESH Headings
- Animals
- Antineoplastic Agents/therapeutic use
- Bradykinin/metabolism
- Calcium/metabolism
- Carcinoma, Small Cell/drug therapy
- Carcinoma, Small Cell/metabolism
- Carcinoma, Small Cell/pathology
- Cell Division/drug effects
- DNA, Neoplasm/metabolism
- Drug Resistance, Neoplasm
- Drug Screening Assays, Antitumor
- Female
- Fibroblasts/metabolism
- Gastrin-Releasing Peptide/pharmacology
- Humans
- Lung Neoplasms/drug therapy
- Lung Neoplasms/metabolism
- Lung Neoplasms/pathology
- Mice
- Mice, Nude
- Peptide Fragments/therapeutic use
- Rats
- Receptors, Bombesin/metabolism
- Receptors, Neuropeptide/metabolism
- Substance P/analogs & derivatives
- Substance P/antagonists & inhibitors
- Substance P/therapeutic use
- Transplantation, Heterologous
- Tumor Cells, Cultured
- Vasopressins/metabolism
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Affiliation(s)
- C M Waters
- Lung Inflammatory Group, Centre for Inflammation Research, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - A C MacKinnon
- Lung Inflammatory Group, Centre for Inflammation Research, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - J Cummings
- Cancer Research UK, Medical Oncology Unit, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK
| | - U Tufail-Hanif
- Lung Inflammatory Group, Centre for Inflammation Research, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - D Jodrell
- Cancer Research UK, Medical Oncology Unit, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK
| | - C Haslett
- Lung Inflammatory Group, Centre for Inflammation Research, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - T Sethi
- Lung Inflammatory Group, Centre for Inflammation Research, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
- Lung Inflammatory Group, Centre for Inflammation Research, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK. E-mail:
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15
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MacKinnon AC, Buckley A, Chilvers ER, Rossi AG, Haslett C, Sethi T. Sphingosine kinase: a point of convergence in the action of diverse neutrophil priming agents. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:6394-400. [PMID: 12444147 DOI: 10.4049/jimmunol.169.11.6394] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Neutrophils are a vital component of the early acute inflammatory response, but can cause profound tissue damage when activated to excess or prevented from undergoing apoptosis. However, much remains unknown about the intracellular signaling pathways regulating neutrophil activity. The structurally diverse neutrophil-priming agents platelet-activating factor, TNF-alpha, and the substance P analog [D-Arg(6), D-Trp(7,9),N(me)Phe(8)]-substance P(6-11) (SP-G) stimulated a rapid increase in sphingosine kinase activity in freshly isolated human neutrophils. This activity was blocked by preincubation with the sphingosine kinase inhibitor N,N-dimethylsphingosine (DMS). DMS also inhibited the increase in intracellular calcium concentration stimulated by platelet-activating factor, fMLP, and SP-G. This suggests that the increase in intracellular calcium concentration by these agents is dependent on sphingosine kinase activation and the generation of sphingosine-1-phosphate. Changes in cell polarization and the augmentation of the fMLP-induced superoxide anion generation, by all priming agents were also inhibited by DMS, while only the superoxide anion release was blocked by the phosphatidylinositol 3-kinase inhibitor LY294002. Moreover, SP-G and GM-CSF inhibited constitutive neutrophil apoptosis which was completely blocked by DMS. These results suggest a novel role for sphingosine kinase in the regulation of neutrophil priming.
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Affiliation(s)
- Alison C MacKinnon
- Lung Inflammatory Group, Center for Inflammation Research, University of Edinburgh, United Kingdom.
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16
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Chan D, Gera L, Stewart J, Helfrich B, Verella-Garcia M, Johnson G, Baron A, Yang J, Puck T, Bunn P. Bradykinin antagonist dimer, CU201, inhibits the growth of human lung cancer cell lines by a "biased agonist" mechanism. Proc Natl Acad Sci U S A 2002; 99:4608-13. [PMID: 11930011 PMCID: PMC123695 DOI: 10.1073/pnas.072077299] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2002] [Indexed: 12/25/2022] Open
Abstract
All small cell (SCLCs) and many non-small cell lung cancers (NSCLCs) have neuroendocrine features including production of neuropeptides and cell surface receptors creating autocrine and paracrine growth loops. Neuropeptides bind to a family of 7-transmembrane receptors and activate heterotrimeric G proteins consisting of G(alphaq) and G(alpha12,13). Substance P derivatives (SPDs) induced apoptosis and inhibited growth of lung cancer cells by discoordinately inhibiting G(alphaq) and stimulating G(alpha12,13). However, these SPDs had low potency and short half-lives. In this report we show that a bradykinin antagonist dimer, CU201, inhibited the growth of SCLC and NSCLC cell lines with or without multidrug-resistant proteins and was 10-fold more potent with a longer plasma half-life than SPDs. Bradykinin agonists in either monomeric or dimeric form and monomeric bradykinin antagonist have no effect on lung cancer cell growth. The dimeric linking moiety of the two molecules was created, requiring a sufficient number of carbon chains to provide critical spacing between the two antagonists. CU201 inhibited intracellular Ca2+ release in response to bradykinin, indicating blockage of the G(alphaq) signal, and stimulated c-Jun kinases, indicating stimulation of the G(alpha12,13) pathway. CU201-induced apoptosis was preceded by unique changes in apparent nuclear DNA binding and by c-Jun kinase and caspase-3 activation. At the concentration at which CU201 inhibited the growth of the cancer cells, it had no effect on the growth of normal lung cells in vitro. CU201 and similar compounds offer hope of becoming a new form of targeted therapy for tumors with neuroendocrine properties.
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Affiliation(s)
- Daniel Chan
- Lung Cancer Program, University of Colorado Cancer Center, Denver, CO 80262, USA.
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17
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Moreira JN, Gaspar R, Allen TM. Targeting Stealth liposomes in a murine model of human small cell lung cancer. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1515:167-76. [PMID: 11718672 DOI: 10.1016/s0005-2736(01)00411-4] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Tumor accumulation and therapeutic activity of Stealth liposomes loaded with doxorubicin (DXR) were examined in Balb/c nude mice xenografts inoculated subcutaneously with the human small cell lung cancer (SCLC) cell line, H69. Mice were treated with non-targeted liposomes (SL) or liposomes targeted with antagonist G coupled to the liposome surface (SLG). SLG showed 30-44-fold higher binding to H69 cells harvested from H69 xenografts than SL. At 48 and 72 h post injection, tumor accumulation of [(125)I]tyraminylinulin-containing liposomes was shown to be dependent on liposome size but independent of the presence of the targeting ligand. Maximum tumor uptake of either SLG or SL ranged from 2 to 4% of injected dose/g of tissue. In therapeutic studies, mice received three weekly injections of 3 or 6 mg free DXR/kg or 3 or 10 mg liposomal DXR/kg at initial tumor volumes of either 7 or 33 mm(3). The therapeutic efficacy of DXR-containing SL or SLG was significantly improved over free DXR, but SLG did not improve anti-tumor efficacy relative to SL. Stealth liposomes containing DXR have potential as a therapy against human SCLC tumors.
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Affiliation(s)
- J N Moreira
- Department of Pharmacology, University of Alberta, Edmonton, Canada
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18
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Moreira JN, Hansen CB, Gaspar R, Allen TM. A growth factor antagonist as a targeting agent for sterically stabilized liposomes in human small cell lung cancer. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1514:303-17. [PMID: 11557029 DOI: 10.1016/s0005-2736(01)00386-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The ability of a growth factor antagonist, [D-Arg(6),D-Trp(7,9)-N(me)Phe(8)]-substance P(6-11), named antagonist G, to selectively target polyethylene glycol-grafted liposomes (known as sterically stabilized liposomes) to a human classical small cell lung cancer (SCLC) cell line, H69, was examined. Our results showed that radiolabeled antagonist G-targeted sterically stabilized liposomes (SLG) bound to H69 cells with higher avidity than free antagonist G and were internalized (reaching a maximum of 13000 SLG/cell), mainly through a receptor-mediated process, likely involving clathrin-coated pits. This interaction was confirmed by confocal microscopy to be peptide- and cell-specific. Moreover, it was shown that SLG significantly improved the nuclear delivery of encapsulated doxorubicin to the target cells, increasing the cytotoxic activity of the drug over non-targeted liposomes. In mice, [(125)I]tyraminylinulin-containing SLG were long circulating, with a half-life of 13 h. Use of peptides like antagonist G to promote binding and internalization of sterically stabilized liposomes, with their accompanying drug loads, i.e., anticancer drugs, genes or antisense oligonucleotides, into target cells has the potential to improve therapy of SCLC.
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Affiliation(s)
- J N Moreira
- Department of Pharmacology, University of Alberta, Edmonton, Canada
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19
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MacKinnon AC, Waters C, Jodrell D, Haslett C, Sethi T. Bombesin and substance P analogues differentially regulate G-protein coupling to the bombesin receptor. Direct evidence for biased agonism. J Biol Chem 2001; 276:28083-91. [PMID: 11323408 DOI: 10.1074/jbc.m009772200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Substance P analogues including [d-Arg1,d-Phe5,d-Trp7,9,Leu11]substance P (SpD) act as "broad spectrum neuropeptide antagonists" and are potential anticancer agents that inhibit the growth of small cell lung cancer cells in vitro and in vivo. However, their mechanism of action is controversial and not fully understood. Although these compounds block bombesin-induced mitogenesis and signal transduction, they also have agonist activity. The mechanism underlying this agonist activity was examined. SpD binds to the ligand-binding site of the bombesin/gastrin-releasing peptide receptor and blocks the bombesin-stimulated increase in [Ca2+]i within the same concentration range that causes sustained activation of c-Jun N-terminal kinase and extracellular signal-regulated protein kinase (ERK). The activation of c-Jun N-terminal kinase by SpD and bombesin is blocked by dominant negative inhibition of G(alpha12). The ERK activation by SpD is pertussis toxin-sensitive in contrast to ERK activation by bombesin, which is pertussis toxin-insensitive but dependent on epidermal growth factor receptor phosphorylation. SpD does not simply act as a partial agonist but differentially modulates the activation of the G-proteins G(alpha12), G(i), and G(q) compared with bombesin. This unique ability allows the bombesin receptor to couple to G(i) and at the same time block receptor activation of G(q). Our results provide direct evidence that SpD is acting as a "biased agonist" and that this has physiological relevance in small cell lung cancer cells. This validation of the concept of biased agonism has important implications in the development of novel pharmacological agents to dissect receptor-mediated signal transduction and of highly selective drugs to treat human disease.
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Affiliation(s)
- A C MacKinnon
- Rayne Laboratory, Centre for Inflammation Research, Respiratory Medicine Unit, University of Edinburgh Medical School, Teviot Place, Edinburgh, EH8 9AG, United Kingdom
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20
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Abstract
Over the past twenty years combination chemotherapy has continued to produce small survival gains for patients with SCLC. We enter the next century enthusiastic about the array of new chemotherapeutic agents to evaluate and fascinated by the biological agents with the hope of achieving dramatic improvements in survival for our patients with SCLC.
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Affiliation(s)
- K Kelly
- University of Colorado Cancer Center, Denver, CO 80220, USA
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21
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Sekine I, Saijo N. Growth-Stimulating Pathways in Lung Cancer: Implications for Targets of Therapy. Clin Lung Cancer 2001; 2:299-306; discussion 307. [PMID: 14720364 DOI: 10.3816/clc.2001.n.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Growth-stimulating pathways activated independently of their normal tissue environment are critical to the carcinogenesis and progression of lung cancer. These pathways are comprised of extracellular growth factors; their specific receptors on the cellular membrane; signal transduction cascades in the cytosol; and target molecules, including cytoskeletal proteins, metabolic regulators, and transcription factors in the nucleus. Growth factors can be divided into two groups based on their receptors: G-protein-coupled receptors and receptor tyrosine kinases. Growth factors induce clonal expansion of lung cancer cells by autocrine and/or paracrine mechanisms. Signal transduction cascades form an extremely large and complicated network with cross-talk connections. Ras, phosphatidylinositol-3-OH kinase, and phospholipase C are three key regulators involved in the network. Recent progress in our understanding of the oncoproteins functioning in the pathways has led to the development of novel therapeutic agents. Some of the most exciting results have been obtained with inhibitors of receptor tyrosine kinases. Phase I studies of epidermal growth factor-receptor inhibitors demonstrate objective responses without severe toxicity as single agents in patients with non-small-cell lung cancer refractory to conventional chemotherapy. This new strategy might lead to breakthroughs in the treatment of lung cancer with distant metastases not curable by conventional chemotherapy alone.
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Affiliation(s)
- I Sekine
- Internal Medicine and Thoracic Oncology Division, National Cancer Center Hospital, Tokyo, Japan.
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22
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Abstract
Autocrine and paracrine signaling leading to stimulation of tumor cell growth is a common theme in human cancers. In addition to polypeptide growth factors such as EGF family members which signal through receptor tyrosine kinases, accumulating evidence supports the autocrine and paracrine involvement of specific neuropeptides with defined physiologic actions as neurotransmitters and gut hormones in lung, gastric, colorectal, pancreatic and prostatic cancers. These neuropeptides, including gastrin-releasing peptide, neuromedin B, neurotensin, gastrin, cholecystokinin and arginine vasopressin bind seven transmembrane-spanning receptors that couple to heterotrimeric G proteins. Studies with human small cell lung cancer (SCLC) cells support a requirement for balanced signaling through G(q) and G(12/13) proteins leading to intracellular Ca2+ mobilization, PKC activation and regulation of the ERK and JNK MAP kinase pathways. While specific neuropeptide antagonists offer promise for interrupting the single neuropeptide autocrine systems operating in pancreatic and prostatic cancers, SCLC is exemplified by multiple, redundant neuropeptide autocrine systems such that tumor growth cannot be inhibited with a single specific antagonist. However, a novel class of neuropeptide derivatives based on the substance P sequence have been defined that exhibit broad specificity for neuropeptide receptors and induce apoptosis in SCLC by functioning as biased agonists that stimulate discordant signal transduction. Thus, interruption of autocrine and paracrine neuropeptide signaling with specific antagonists or broad-spectrum biased agonists offer promising new therapeutic approaches to the treatment of human cancers.
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Affiliation(s)
- L E Heasley
- Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado, CO 80262, USA
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23
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Sinnett-Smith J, Santiskulvong C, Duque J, Rozengurt E. [D-Arg(1),D-Trp(5,7,9),Leu(11)]Substance P inhibits bombesin-induced mitogenic signal transduction mediated by both G(q) and G(12) in Swiss 3T3cells. J Biol Chem 2000; 275:30644-52. [PMID: 10880515 DOI: 10.1074/jbc.m003702200] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Substance P (SP) analogues including [d-Arg(1),d-Trp(5,7,9), Leu(11)]SP are broad spectrum neuropeptide antagonists and potential anticancer agents, but their mechanism of action is not fully understood. Here, we examined the mechanism of action of [d-Arg(1), d-Trp(5,7,9),Leu(11)]SP as an inhibitor of G protein-coupled receptor (GPCR)-mediated signal transduction and cellular DNA synthesis in Swiss 3T3 cells. Addition of [d-Arg(1),d-Trp(5,7,9), Leu(11)]SP, at 10 micrometer, caused a striking rightward shift in the dose-response curves of DNA synthesis induced by bombesin, bradykinin, or vasopressin and markedly inhibited the activation of p42(mapk) (ERK-2) and p44(mapk) (ERK-1) induced by these GPCR agonists. In addition, this SP analogue also prevented the protein kinase C-dependent activation of protein kinase D induced by these agonists. [d-Arg(1),d-Trp(5,7,9),Leu(11)]SP, at a concentration (10 micrometer) that inhibited these G(q)-mediated events, also prevented GPCR agonist-induced responses mediated through the G proteins of the G(12) subfamily. These include bombesin-induced assembly of focal adhesions, formation of parallel arrays of actin stress fibers, increase in the tyrosine phosphorylation of focal adhesion kinase (FAK), p130(Cas), and paxillin, and formation of a complex between FAK and Src. We conclude that [d-Arg(1),d-Trp(5,7,9),Leu(11)]SP acts as a mitogenic antagonist of neuropeptide GPCRs blocking signal transduction via both G(q) and G(12).
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Affiliation(s)
- J Sinnett-Smith
- Department of Medicine, School of Medicine and Molecular Biology Institute, UCLA, Los Angeles, California 90095-1786, USA
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24
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Cummings J, MacLellan AJ, Mark M, Jodrell DI. Development of a gradient elution high-performance liquid chromatography assay with ultraviolet detection for the determination in plasma of the anticancer peptide [Arg6, D-Trp7,9, mePhe8]-substance P (6-11) (antagonist G), its major metabolites and a C-terminal pyrene-labelled conjugate. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1999; 732:277-85. [PMID: 10517349 DOI: 10.1016/s0378-4347(99)00294-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
[Arg6, D-Trp7,9 mePhe8]-substance P (6-11), code-named antagonist G, is a novel peptide currently undergoing early clinical trials as an anticancer drug. A sensitive, high efficiency high-performance liquid chromatography (HPLC) method is described for the determination in human plasma of antagonist G and its three major metabolites, deamidated-G (M1), G-minus Met11 (M2) and G[Met11(O)] (M3). Gradient elution was employed using 40 mM ammonium acetate in 0.15% trifluoroacetic acid as buffer A and acetonitrile as solvent B, with a linear gradient increasing from 30 to 100% B over 15 min, together with a microbore analytical column (microBondapak C18, 30 cm X 2 mm I.D.). Detection was by UV at 280 nm and the column was maintained at 40 degrees C. Retention times varied by <1% throughout the day and were as follows: G, 13.0 min; M1, 12.2 min; M2, 11.2 min; M3, 10.8 min, and 18.1 min for a pyrene conjugate of G (G-P). The limit of detection on column (LOD) was 2.5 ng for antagonist G, M1-3 and G-P and the limit of quantitation (LOQ) was 20 ng/ml for G and 100 ng/ml for M1-3. Sample clean-up by solid-phase extraction using C2-bonded 40 microm silica particles (Bond Elut, 1 ml reservoirs) resulted in elimination of interference from plasma constituents. Within-day and between-day precision and accuracy over a broad range of concentrations (100 ng/ml-100 microg/ml) normally varied by < 10%, although at the highest concentrations of M1 and M2 studied (50 microg/ml), increased variability and reduced recovery were observed. The new assay will aid in the clinical development of antagonist G.
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Affiliation(s)
- J Cummings
- Imperial Cancer Research Fund, Medical Oncology Unit, Western General Hospital, Edinburgh, UK
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