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Therapeutic Strategies Targeting Urokinase and Its Receptor in Cancer. Cancers (Basel) 2022; 14:cancers14030498. [PMID: 35158766 PMCID: PMC8833673 DOI: 10.3390/cancers14030498] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 01/11/2022] [Accepted: 01/15/2022] [Indexed: 01/19/2023] Open
Abstract
Several studies have ascertained that uPA and uPAR do participate in tumor progression and metastasis and are involved in cell adhesion, migration, invasion and survival, as well as angiogenesis. Increased levels of uPA and uPAR in tumor tissues, stroma and biological fluids correlate with adverse clinic-pathologic features and poor patient outcomes. After binding to uPAR, uPA activates plasminogen to plasmin, a broad-spectrum matrix- and fibrin-degrading enzyme able to facilitate tumor cell invasion and dissemination to distant sites. Moreover, uPAR activated by uPA regulates most cancer cell activities by interacting with a broad range of cell membrane receptors. These findings make uPA and uPAR not only promising diagnostic and prognostic markers but also attractive targets for developing anticancer therapies. In this review, we debate the uPA/uPAR structure-function relationship as well as give an update on the molecules that interfere with or inhibit uPA/uPAR functions. Additionally, the possible clinical development of these compounds is discussed.
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2
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Rai J. Peptide and protein mimetics by retro and retroinverso analogs. Chem Biol Drug Des 2019; 93:724-736. [PMID: 30582286 DOI: 10.1111/cbdd.13472] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 12/10/2018] [Accepted: 12/16/2018] [Indexed: 12/19/2022]
Abstract
Retroinverso analog of a natural polypeptide can sometimes mimic the structure and function of the natural peptide. The additional advantage of using retroinverso analog is that it is resistant to proteolysis. The retroinverso analogs have peptide sequence in reverse direction with respect to natural peptide and also have chirality of amino acid inverted from L to D. The D amino acids cannot be recognized by common proteases of the body; therefore, these peptides will not be degraded easily and have a longer-lasting effect as vaccine and inhibitor drugs. There have been many contested propositions about the geometric relationship between a peptide and its retro, inverso, or retroinverso analog. A retroinverso analog sometimes fails to adopt the structure that can mimic the function of the natural peptide. In such cases, partial retroinverso analog and other modifications can help in achieving the desired structure and function. Here, we review the theory, major experimental attempts, prediction methods, and alternative strategies related to retroinverso peptidomimetics.
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3
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Requirements for Empirical Immunogenicity Trials, Rather than Structure-Based Design, for Developing an Effective HIV Vaccine. HIV/AIDS: IMMUNOCHEMISTRY, REDUCTIONISM AND VACCINE DESIGN 2019. [PMCID: PMC7122000 DOI: 10.1007/978-3-030-32459-9_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The claim that it is possible to rationally design a structure-based HIV-1 vaccine is based on misconceptions regarding the nature of protein epitopes and of immunological specificity. Attempts to use reverse vaccinology to generate an HIV-1 vaccine on the basis of the structure of viral epitopes bound to monoclonal neutralizing antibodies have failed so far because it was not possible to extrapolate from an observed antigenic structure to the immunogenic structure required in a vaccine. Vaccine immunogenicity depends on numerous extrinsic factors such as the host immunoglobulin gene repertoire, the presence of various cellular and regulatory mechanisms in the immunized host and the process of antibody affinity maturation. All these factors played a role in the appearance of the neutralizing antibody used to select the epitope to be investigated as potential vaccine immunogen, but they cannot be expected to be present in identical form in the host to be vaccinated. It is possible to rationally design and optimize an epitope to fit one particular antibody molecule or to improve the paratope binding efficacy of a monoclonal antibody intended for passive immunotherapy. What is not possible is to rationally design an HIV-1 vaccine immunogen that will elicit a protective polyclonal antibody response of predetermined efficacy. An effective vaccine immunogen can only be discovered by investigating experimentally the immunogenicity of a candidate molecule and demonstrating its ability to induce a protective immune response. It cannot be discovered by determining which epitopes of an engineered antigen molecule are recognized by a neutralizing monoclonal antibody. This means that empirical immunogenicity trials rather than structural analyses of antigens offer the best hope of discovering an HIV-1 vaccine.
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4
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Ragone C, Minopoli M, Ingangi V, Botti G, Fratangelo F, Pessi A, Stoppelli MP, Ascierto PA, Ciliberto G, Motti ML, Carriero MV. Targeting the cross-talk between Urokinase receptor and Formyl peptide receptor type 1 to prevent invasion and trans-endothelial migration of melanoma cells. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2017; 36:180. [PMID: 29216889 PMCID: PMC5721612 DOI: 10.1186/s13046-017-0650-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 11/23/2017] [Indexed: 12/16/2022]
Abstract
BACKGROUND Accumulating evidence demonstrates that the Urokinase Receptor (uPAR) regulates tumor cell migration through its assembly in composite regulatory units with transmembrane receptors, and uPAR88-92 is the minimal sequence required to induce cell motility through the Formyl Peptide Receptor type 1 (FPR1). Both uPAR and FPR1 are involved in melanoma tumor progression, suggesting that they may be targeted for therapeutic purposes. In this study, the role of the uPAR-FPR1 cross-talk to sustain melanoma cell ability to invade extracellular matrix and cross endothelial barriers is investigated. Also, the possibility that inhibition of the uPAR mediated FPR1-dependent signaling may prevent matrix invasion and transendothelial migration of melanoma cells was investigated. METHODS Expression levels of uPAR and FPR1 were assessed by immunocytochemistry, Western Blot and qRT-PCR. Cell migration was investigated by Boyden chamber and wound-healing assays. Migration and invasion kinetics, trans-endothelial migration and proliferation of melanoma cells were monitored in real time using the xCELLigence technology. The agonist-triggered FPR1 internalization was visualized by confocal microscope. Cell adhesion to endothelium was determined by fluorometer measurement of cell-associated fluorescence or identified on multiple z-series by laser confocal microscopy. The 3D-organotypic models were set up by seeding melanoma cells onto collagen I matrices embedded dermal fibroblasts. Data were analyzed by one-way ANOVA and post-hoc Dunnett t-test for multiple comparisons. RESULTS We found that the co-expression of uPAR and FPR1 confers to A375 and M14 melanoma cells a clear-cut capability to move towards chemotactic gradients, to cross extracellular matrix and endothelial monolayers. FPR1 activity is required, as cell migration and invasion were abrogated by receptor desensitization. Finally, melanoma cell ability to move toward chemotactic gradients, invade matrigel or fibroblast-embedded collagen matrices and cross endothelial monolayers are prevented by anti-uPAR84-95 antibodies or by the RI-3 peptide which we have previously shown to inhibit the uPAR84-95/FPR1 interaction. CONCLUSIONS Collectively, our findings identify uPAR and FPR1 as relevant effectors of melanoma cell invasiveness and suggest that inhibitors of the uPAR84-95/FPR1 cross-talk may be useful for the treatment of metastatic melanoma.
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Affiliation(s)
- Concetta Ragone
- IRCCS Istituto Nazionale Tumori 'Fondazione G. Pascale', Naples, Italy.,University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Michele Minopoli
- IRCCS Istituto Nazionale Tumori 'Fondazione G. Pascale', Naples, Italy.,University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Vincenzo Ingangi
- IRCCS Istituto Nazionale Tumori 'Fondazione G. Pascale', Naples, Italy.,University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Giovanni Botti
- IRCCS Istituto Nazionale Tumori 'Fondazione G. Pascale', Naples, Italy.,University of Campania "Luigi Vanvitelli", Naples, Italy
| | | | | | | | | | | | - Maria Letizia Motti
- IRCCS Istituto Nazionale Tumori 'Fondazione G. Pascale', Naples, Italy. .,University 'Parthenope', Via Acton 38, 80133, Naples, Italy.
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5
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Retro-inverso Urokinase Receptor Antagonists for the Treatment of Metastatic Sarcomas. Sci Rep 2017; 7:1312. [PMID: 28465589 PMCID: PMC5430962 DOI: 10.1038/s41598-017-01425-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 03/29/2017] [Indexed: 11/12/2022] Open
Abstract
The development of metastases is a multistep process that requires the activation of physiological and biochemical processes that govern migration, invasion and entry of metastatic cells into blood vessels. The urokinase receptor (uPAR) promotes cell migration by interacting with the Formyl Peptide Receptors (FPRs). Since both uPAR and FPR1 are involved in tumor progression, the uPAR-FPR1 interaction is an attractive therapeutic target. We previously described peptide antagonists of the uPAR-FPR1 interaction that inhibited cell migration and angiogenesis. To develop enzyme-resistant analogues, we applied here the Retro-Inverso (RI) approach, whereby the topology of the side chains is maintained by inverting the sequence of the peptide and the chirality of all residues. Molecular dynamics suggests that peptide RI-3 adopts the turn structure typical of uPAR-FPR1 antagonists. Accordingly, RI-3 is a nanomolar competitor of N-formyl-Met-Leu-Phe for binding to FPR1 and inhibits migration, invasion, trans-endothelial migration of sarcoma cells and VEGF-triggered endothelial tube formation. When sarcoma cells were subcutaneously injected in nude mice, tumor size, intra-tumoral microvessel density, circulating tumor cells and pulmonary metastases were significantly reduced in animals treated daily with 6 mg/Kg RI-3 as compared to animals treated with vehicle only. Thus, RI-3 represents a promising lead for anti-metastatic drugs.
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6
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Liu M, Li X, Xie Z, Xie C, Zhan C, Hu X, Shen Q, Wei X, Su B, Wang J, Lu W. D-Peptides as Recognition Molecules and Therapeutic Agents. CHEM REC 2016; 16:1772-86. [PMID: 27255896 DOI: 10.1002/tcr.201600005] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Indexed: 01/13/2023]
Abstract
Over recent years, D-peptides have attracted increasing attention. D-peptides increase enzymatic stability, prolong the plasma half-life, improve oral bioavailability, and enhance binding activity and specificity with receptor or target proteins, in comparison with the corresponding L-peptide. Therefore, D-peptides are considered to have potential as recognition molecules and therapeutic agents. This review focuses on the design and application of D-peptides with biological activity.
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Affiliation(s)
- Min Liu
- Key Laboratory of Smart Drug Delivery (Fudan University)Ministry of Education Department of Pharmaceutics School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203 (P. R. China)
| | - Xue Li
- Key Laboratory of Smart Drug Delivery (Fudan University)Ministry of Education Department of Pharmaceutics School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203 (P. R. China)
| | - Zuoxu Xie
- Key Laboratory of Smart Drug Delivery (Fudan University)Ministry of Education Department of Pharmaceutics School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203 (P. R. China)
| | - Cao Xie
- Key Laboratory of Smart Drug Delivery (Fudan University)Ministry of Education Department of Pharmaceutics School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203 (P. R. China)
| | - Changyou Zhan
- Key Laboratory of Smart Drug Delivery (Fudan University)Ministry of Education Department of Pharmaceutics School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203 (P. R. China).,Department of Pharmacology School of Basic Medical Sciences, Fudan University, 138 Yixueyuan Road, Shanghai 200032 (P. R. China)
| | - Xuefeng Hu
- Key Laboratory of Smart Drug Delivery (Fudan University)Ministry of Education Department of Pharmaceutics School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203 (P. R. China)
| | - Qing Shen
- Key Laboratory of Smart Drug Delivery (Fudan University)Ministry of Education Department of Pharmaceutics School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203 (P. R. China)
| | - Xiaoli Wei
- Key Laboratory of Smart Drug Delivery (Fudan University)Ministry of Education Department of Pharmaceutics School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203 (P. R. China)
| | - Bingxia Su
- Key Laboratory of Smart Drug Delivery (Fudan University)Ministry of Education Department of Pharmaceutics School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203 (P. R. China)
| | - Jing Wang
- Key Laboratory of Smart Drug Delivery (Fudan University)Ministry of Education Department of Pharmaceutics School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203 (P. R. China)
| | - Weiyue Lu
- Key Laboratory of Smart Drug Delivery (Fudan University)Ministry of Education Department of Pharmaceutics School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203 (P. R. China)
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7
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Croft NP, Purcell AW. Peptidomimetics: modifying peptides in the pursuit of better vaccines. Expert Rev Vaccines 2014; 10:211-26. [DOI: 10.1586/erv.10.161] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Van Regenmortel MHV. Requirements for empirical immunogenicity trials, rather than structure-based design, for developing an effective HIV vaccine. Arch Virol 2011; 157:1-20. [PMID: 22012269 PMCID: PMC7087187 DOI: 10.1007/s00705-011-1145-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 10/07/2011] [Indexed: 11/29/2022]
Abstract
The claim that it is possible to rationally design a structure-based HIV-1 vaccine is based on misconceptions regarding the nature of protein epitopes and of immunological specificity. Attempts to use reverse vaccinology to generate an HIV-1 vaccine on the basis of the structure of viral epitopes bound to monoclonal neutralizing antibodies have failed so far because it was not possible to extrapolate from an observed antigenic structure to the immunogenic structure required in a vaccine. Vaccine immunogenicity depends on numerous extrinsic factors such as the host immunoglobulin gene repertoire, the presence of various cellular and regulatory mechanisms in the immunized host and the process of antibody affinity maturation. All these factors played a role in the appearance of the neutralizing antibody used to select the epitope to be investigated as potential vaccine immunogen, but they cannot be expected to be present in identical form in the host to be vaccinated. It is possible to rationally design and optimize an epitope to fit one particular antibody molecule or to improve the paratope binding efficacy of a monoclonal antibody intended for passive immunotherapy. What is not possible is to rationally design an HIV-1 vaccine immunogen that will elicit a protective polyclonal antibody response of predetermined efficacy. An effective vaccine immunogen can only be discovered by investigating experimentally the immunogenicity of a candidate molecule and demonstrating its ability to induce a protective immune response. It cannot be discovered by determining which epitopes of an engineered antigen molecule are recognized by a neutralizing monoclonal antibody. This means that empirical immunogenicity trials rather than structural analyses of antigens offer the best hope of discovering an HIV-1 vaccine.
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Affiliation(s)
- Marc H V Van Regenmortel
- Stellenbosch Institute of Advanced Study, Wallenberg Research Center at Stellenbosch University, Stellenbosch 7600, South Africa.
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9
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Pal-Bhowmick I, Pandey RP, Jarori GK, Kar S, Sahal D. Structural and functional studies on Ribonuclease S, retro S and retro-inverso S peptides. Biochem Biophys Res Commun 2007; 364:608-13. [PMID: 17963728 DOI: 10.1016/j.bbrc.2007.10.056] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Accepted: 10/10/2007] [Indexed: 11/30/2022]
Abstract
Ribonuclease S peptide and S protein offer a unique complementation system to understand the finer features of molecular recognition. In the present study the S peptide (1-16), and its retro and retro-inverso analogs have been analyzed for their structural and biological attributes. RPHPLC, CD, and NMR analyses have revealed that the physicochemical and conformational properties of the S peptide are distinct from those of its retro and retro-inverso analogs. On the functional side, while the S peptide complemented the S protein to give RNase activity, was recognized by anti-S peptide antibodies and induced T cell proliferation, neither the retro nor the retro-inverso S peptides could do so.
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10
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Abstract
In the mid-1970s, Dr. Murray Goodman was interested in a reversed peptide bond as a surrogate to understand the functional role of the amide bond in aspartame, a dipeptide sweetener. Very soon, realizing the breath and potential of this modification, Murray expanded this activity into a full program and I was fortunate to be part of it. Together we formulated new concepts such as the partially modified retro-inverso and end-group modified retro-inverso transformations, tested hypotheses, generated novel nomenclature, developed synthetic routes, characterized the preferred conformations of the unique building blocks employed in this modification, the gem-diaminoalkyl and the C2-substituted malonyl residues, and studied the biological activity of retro-inverso isomers of bioactive peptides. In the early 1980s several laboratories initiated extensive research targeted at the retro-inverso modification. The revival of this field led to new applications, new methods of synthesis, and new insights on the conformational and topological properties of the retro-inverso modification. Among the fields that embraced the retro-inverso concept were immunology as pertains to subjects such as synthetic vaccines, immunomodulators, and diagnostic tools, and drug delivery field as pertains to targeted and nontargeted cell permeation vectors loaded with bioactive cargo. Doctor Murray Goodman's sudden death leaves behind not only family, friends, and colleagues, but also an impressive record of scientific achievements among which is the revival of the modern era of the retro-inverso transformation. Murray's numerous contributions, excellent leadership, enthusiastic promotion, and outstanding teachings in this field will carry and illuminate his memory far into the future.
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Affiliation(s)
- Michael Chorev
- Harvard Medical School, Laboratory for Translational Research, One Kendall Square, Building 600, 3rd Floor, Cambridge, MA 02139, USA.
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11
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Yang D, Li W, Qu J, Luo SW, Wu YD. A new strategy to induce gamma-turns: peptides composed of alternating alpha-aminoxy acids and alpha-amino acids. J Am Chem Soc 2004; 125:13018-9. [PMID: 14570462 DOI: 10.1021/ja036136p] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
It is known that the seven-membered-ring intramolecular hydrogen bond (gamma-turn) is seldom formed in naturally occurring peptides composed of alpha-amino acids. Here we report a new strategy to induce gamma-turns in short linear peptides. We designed and synthesized several peptides (1-5) containing alternating alpha-l-aminoxy acids and alpha-d-amino acids. 1H NMR studies revealed that the gamma-turn could be initiated by the following N-O turn, an eight-membered-ring intramolecular hydrogen bond induced by an alpha-aminoxy acid. Moreover, NOESY and CD studies suggested peptides 4 and 5 form a novel secondary structure, a mixed 7-8 helix. Theoretical calculations on several di-, tri-, and tetrapeptide models provided strong support to the above conclusions.
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Affiliation(s)
- Dan Yang
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
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12
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Nair DT, Kaur KJ, Singh K, Mukherjee P, Rajagopal D, George A, Bal V, Rath S, Rao KVS, Salunke DM. Mimicry of native peptide antigens by the corresponding retro-inverso analogs is dependent on their intrinsic structure and interaction propensities. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:1362-73. [PMID: 12538696 DOI: 10.4049/jimmunol.170.3.1362] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Retro-inverso (ri) analogs of model T cell and B cell epitopes were predictively designed as mimics and then assayed for activity to understand the basis of functional ri-antigenic peptide mimicry. ri versions of two MHC class I binding peptide epitopes, one from a vesicular stomatitis virus glycoprotein (VSV(p)) and another from OVA (OVAp), exhibit structural as well as functional mimicry of their native counterparts. The two ri peptides exhibit conformational plasticity and they bind to MHC class I (H-2K(b)) similar to their native counterparts both in silico and in vivo. In fact, ri-OVAp is also presented to an OVAp-specific T cell line in a mode similar to native OVAp. In contrast, the ri version of an immunodominant B cell peptide epitope from a hepatitis B virus protein, PS1, exhibits no structural or functional correlation with its native counterpart. PS1 and its ri analog do not exhibit similar conformational propensities. PS1 is less flexible relative to its ri version. These observed structure-function relationships of the ri-peptide epitopes are consistent with the differences in recognition properties between peptide-MHC vs peptide-Ab binding where, while the recognition of the epitope by MHC is pattern based, the exquisitely specific recognition of Ag by Ab arises from the high complementarity between the Ag and the binding site of the Ab. It is evident that the correlation of conformational and interaction propensities of native L-peptides and their ri counterparts depends both on their inherent structural properties and on their mode of recognition.
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13
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Iwai LK, Duranti MA, Abel LC, Juliano MA, Kalil J, Juliano L, Cunha-Neto E. Retro-inverso peptide analogues of Trypanosoma cruzi B13 protein epitopes fail to be recognized by human sera and peripheral blood mononuclear cells. Peptides 2001; 22:853-60. [PMID: 11390013 DOI: 10.1016/s0196-9781(01)00409-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Retro inverso (RI) analogues of antigenic synthetic peptides, which are made of D-amino acids with a reversed sequence, may mimic the side chain conformation of natural all-L peptides. RI analogues were cross-reactively recognized by antibodies and CD4+ T cells reactive against natural all-L synthetic peptides or native proteins in animal models. Since peptides containing D-amino acids are highly resistant to proteolytic digestion, cross-reactive RI analogues may be ideal for in vivo administration to humans as synthetic peptide vaccines or immunomodulators. B13 is an immunodominant tandemly repetitive protein from Trypanosoma cruzi, a protozoan parasite that is the causative antigen of Chagas' disease. In order to test whether RI peptides can be recognized by human antibody and T cells, we synthesized two all-L peptides containing the immunodominant B (S12) and T (S15.7) cell epitopes of B13 protein from T. cruzi and their retro (R, made of all-L amino acids with reversed sequence), inverso (I, made of all-D amino acids) and RI analogues. Recognition of peptides S12, S12-R, S12-I and S12-RI by anti-B13 antibodies in sera from T. cruzi-infected patients was tested in competitive ELISA assay with recombinant B13 protein as the solid phase antigen. Peptides S15.7 and its topological analogues were tested at the 10-50 microM range in proliferation assays on peripheral blood mononuclear cells (PBMC) from S15.7-responder individuals. The median percentage inhibition of B13 ELISA for peptide S12 was 94%, while those of the RI analogue or the other topological analogues were below 12%. While peptide S15.7 was recognized by PBMC from all subjects tested, none recognized the RI analogue of the S15.7 T cell epitope. Our results indicate that cross-reactivity with natural epitopes is not an universal property of RI analogues. This may limit the general applicability of the use of cross-reactive RI analogues as human vaccines and immunotherapeutic agents.
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Affiliation(s)
- L K Iwai
- Laboratory of Immunology, Heart Institute (InCor), and Division of Allergy and Immunopathology, Department of Medicine, University of São Paulo School of Medicine, São Paulo, Brazil
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Abstract
Pathological changes in the microtubule associated protein tau, leading to tau-containing filamentous lesions, are a major hallmark common to many types of human neurodegenerative diseases, including Alzheimer's disease (AD). No structural data are available which could rationalize the extensive conformational changes that occur when tau protein is converted to Alzheimer's paired helical filaments (PHF). The C-terminal portion of tau plays a crucial role in the aggregation of tau into PHF and in the truncation process that generates cytotoxic segments of tau. Therefore, we investigated the solution structure of the hydrophobic C-terminal segment 423-441 of tau protein (PQLATLADEVSASLAKQGL) by 1H 2D NMR spectroscopy. The peptide displays the typical NMR evidence consistent with a alpha-helix geometry with a stabilizing C-capping motif. The reported data represent the first piece of structural information on an important portion of the molecule and can have implications towards the understanding of its pathophysiology.
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Affiliation(s)
- G Esposito
- Dipartimento di Scienze e Tecnologie Biomediche, Università di Udine, Italy.
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Beglova N, Maliartchouk S, Ekiel I, Zaccaro MC, Saragovi HU, Gehring K. Design and solution structure of functional peptide mimetics of nerve growth factor. J Med Chem 2000; 43:3530-40. [PMID: 11000007 DOI: 10.1021/jm990441x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The C-D loop in nerve growth factor (NGF) is involved in binding to the NGF receptor, TrkA. It is flexible and adopts several different types conformations in different NGF crystal forms. We have previously shown that a small cyclic peptide derived from the C-D loop of NGF binds to the TrkA receptor by mimicking the structure of this loop. To understand structure-function relationships in NGF C-D loop mimetics, we have produced a series of peptides predicted to form different types of beta-turns. The peptides were tested for their ability to promote cell survival in serum-free medium and to induce TrkA tyrosine phosphorylation. NMR structural studies were used to determined the backbone conformation and the spatial orientation of side chains involved in binding to the TrkA receptor. Peptides that form type I or type gammaL-alphaR beta-turns were the most active. The variety of active loop conformations suggests that the mimetics (and NGF) accommodate the binding site on TrkA by an 'induced fit' mechanism. In agreement with this hypothesis, NMR relaxation measurements detected both fast and slow motion in the peptides. We also characterized a retro-inverso peptide derived from the NGF C-D loop. This D-amino acid cyclic peptide did not adopt a conformation homologous to the NGF C-D loop and was inactive. This may be representative of difficulties in producing structural and functional mimetics by retro-inverso schemes.
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Affiliation(s)
- N Beglova
- Department of Biochemistry and Montreal Joint Centre for Structural Biology, McGill University, 3655 Promenade Sir William Osler, Montréal, Québec H3G 1Y6, Canada
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16
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Apletalina EV, Juliano MA, Juliano L, Lindberg I. Structure-function analysis of the 7B2 CT peptide. Biochem Biophys Res Commun 2000; 267:940-2. [PMID: 10673395 DOI: 10.1006/bbrc.1999.2060] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Prohormone convertases play important roles in the proteolytic conversion of many protein precursors. The neuroendocrine protein 7B2 and its 31-residue carboxyl-terminal (CT) peptide potently and specifically inhibit prohormone convertase 2 (PC2). We have analyzed the residues contributing to inhibition using N-terminal truncation and alanine scanning. Removal of more than 3 residues from the amino-terminal end of CT1-18 resulted in a more than 190-fold drop in inhibitory activity, showing that most of the residues between 3 and 18 are required for inhibition. In agreement, an Ala scan indicated that only 4 residues could be replaced with Ala without losing mid-nanomolar inhibitory potency; in particular, Gln7, Gln9, and Asp12 could be Ala-substituted to yield peptides with a similar inhibitory potency to the starting peptide. The all-d-retro-inverso, all-l-inverso, and all-d analogues of CT peptide were completely inactive, indicating that amino acid side chains and the CT peptide main chain interact with PC2. CT peptide inhibition could not be competitively blocked by preincubation with truncated CT peptide forms, supporting an absolute requirement for the Lys-Lys pair in initial binding of the CT peptide to the active site.
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Affiliation(s)
- E V Apletalina
- Department of Biochemistry, Louisiana State University Health Sciences Center, New Orleans, Louisiana, 70112, USA
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Levi M, Hinkula J, Wahren B. A retro-inverso miniantibody with anti-HIV activity. AIDS Res Hum Retroviruses 2000; 16:59-65. [PMID: 10628817 DOI: 10.1089/088922200309601] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
An HIV-1-specific miniantibody, a peptide representing the third heavy chain complementarity-determining region (CDR) of an HIV-specific mouse antibody, was characterized and modified with unnatural D-isomeric amino acids. The CDR peptide and its parent antibody bound to a similar epitope, located in the V3 region of HIV-1 gp120. A shortened CDR sequence was modified with D-amino acids to create an all-D-amino acid retro-inverso (RI) peptide with a reversed sequence order. The RI CDR was less susceptible to proteolytic degradation than its L-counterpart and had a higher affinity for HIV-1 peptides. The miniantibody and its parent antibody showed neutralization of both primary and laboratory strains of HIV-1. In accordance with the binding studies, the RI CDR showed a stronger HIV-inhibiting capacity than its L-counterpart. We conclude that the anti-HIV retro-inverso CDR identified in this study has the potential to become a future anti-HIV drug. It has a virus-neutralizing capacity in vitro and appears to be stable. Future research should focus on characterizing its antiviral activity in vivo.
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Affiliation(s)
- M Levi
- Department of Virology, Swedish Institute for Infectious Disease Control and Karolinska Institute, Solna.
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Petit MC, Benkirane N, Guichard G, Du AP, Marraud M, Cung MT, Briand JP, Muller S. Solution structure of a retro-inverso peptide analogue mimicking the foot-and-mouth disease virus major antigenic site. Structural basis for its antigenic cross-reactivity with the parent peptide. J Biol Chem 1999; 274:3686-92. [PMID: 9920919 DOI: 10.1074/jbc.274.6.3686] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The antigenic activity of a 19-mer peptide corresponding to the major antigenic region of foot-and-mouth disease virus and its retro-enantiomeric analogue was found to be completely abolished when they were tested in a biosensor system in trifluoroethanol. This suggests that the folding pattern, which is alpha-helix in trifluoroethanol (confirmed by CD measurement), does not correspond to the biologically relevant conformation(s) recognized by antibodies. The NMR structures of both peptides were thus determined in aqueous solution. These studies showed that the two peptides exhibit similar folding features, particularly in their C termini. This may explain in part the cross-reactive properties of the two peptides in aqueous solution. However, the retro-inverso analogue appears to be more rigid than the parent peptide and contains five atypical beta-turns. This feature may explain why retro-inverso foot-and-mouth disease virus peptides are often better recognized than the parent peptide by anti-virion antibodies.
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Affiliation(s)
- M C Petit
- Laboratoire de Chimie-Physique Macromoléculaire, UMR 7568 CNRS, ENSIC-INPL, 54000 Nancy, France
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Starkey JR, Dai S, Dratz EA. Sidechain and backbone requirements for anti-invasive activity of laminin peptide 11. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1429:187-207. [PMID: 9920396 DOI: 10.1016/s0167-4838(98)00236-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The structure of laminin peptide 11 (CDPGYIGSR-NH2) contains valuable information for the design of mimetic compounds with anti-invasive and anti-metastatic properties. An alanine scan replacement experiment identified Tyr5, Ile6 and Arg9 residues as contributing significantly to anti-invasive activity. Circular dichroism spectra and NMR alphaH chemical shift values both supported the existence of populations of nonrandom coil solution structures for the analogs tested. A D-Ala4 for Gly4 substituted analog completely lost activity, while an L-Ala4 for Gly4 substituted analog retained half the activity of the parent peptide. These results complement our previous findings with D/L alanine substitutions at the Gly7 position, and together they suggest an 'S'-shaped backbone as likely for the active peptide conformation. NMR-constrained molecular modeling supported a direct involvement of the Tyr5 and Ile6 sidechains in conferring bioactivity, and indicated that the Tyr5 sidechain was buried in the Ala2 for Asp2 substitution. Based on the fact that the peptide 11 sequence derives from the disulfide bonded c-loop of an LE-repeat, we synthesized the cyclic CDPGYIGSRC-NH2 peptide. This analog exhibited good anti-invasive and anti-metastatic activity. NMR modeling experiments suggested that the trans-proline cyclic peptide, would favor an 'S'-shaped backbone conformation. Full retro-inverso analogs of peptide 11 were shown to have anti-invasive activity inferior to that of peptide 11. This weak bioactivity was probed using NMR-constrained molecular dynamics, and revealed potential conformations which limited the ability of the required sidechains to mimic the positions of those in the native peptide conformations.
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Affiliation(s)
- J R Starkey
- Department of Microbiology, Montana State University, Bozeman 59717, USA.
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Abstract
There has been a regain of interest in the immunological applications of peptides assembled partly or totally from D-amino acids. Such peptides are much more stable to proteolysis than natural L-peptides and they have considerable potential as synthetic vaccines and as immunomodulators in T-cell responses. Retro-inverso, also called retro-all-D or retroenantio, peptide analogues that closely mimic the structure of protein antigens are obtained by assembling amino acid residues in the reverse order from that in the parent peptides and replacing L- by D-amino acids. Retro-all-D peptides corresponding to an immunodominant epitope of foot-and-mouth disease virus have been shown to elicit high levels of neutralizing antibodies in experimental animals. Certain retro-all-D peptide analogues of T-cell epitopes are able to bind to MHC class II molecules and may either lead to T-cell activation or inhibit deleterious T-cell responses.
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Fletcher MD, Campbell MM. Partially Modified Retro-Inverso Peptides: Development, Synthesis, and Conformational Behavior. Chem Rev 1998; 98:763-796. [PMID: 11848914 DOI: 10.1021/cr970468t] [Citation(s) in RCA: 160] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Briand JP, Benkirane N, Guichard G, Newman JF, Van Regenmortel MH, Brown F, Muller S. A retro-inverso peptide corresponding to the GH loop of foot-and-mouth disease virus elicits high levels of long-lasting protective neutralizing antibodies. Proc Natl Acad Sci U S A 1997; 94:12545-50. [PMID: 9356486 PMCID: PMC25032 DOI: 10.1073/pnas.94.23.12545] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Peptides corresponding to the immunodominant loop located at residues 135-158 on capsid protein VP1 of foot-and-mouth disease virus (FMDV) generally elicit high levels of anti-peptide and virus-neutralizing antibodies. In some instances, however, the level of neutralizing antibodies is low or even negligible, even though the level of anti-peptide antibodies is high. We have shown previously that the antigenic activity of peptide 141-159 of VP1 of a variant of serotype A can be mimicked by a retro-inverso (all-D retro or retroenantio) peptide analogue. This retro-inverso analogue induced greater and longer-lasting antibody titers than did the corresponding L-peptide. We now show that a single inoculation of the retro-inverso analogue elicits high levels of neutralizing antibodies that persist longer than those induced against the corresponding L-peptide and confer substantial protection in guinea pigs challenged with the cognate virus. In view of the high stability to proteases of retro-inverso peptide analogues and their enhanced immunogenicity, these results have practical relevance in designing potential peptide vaccines.
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Affiliation(s)
- J P Briand
- Institut de Biologie Moléculaire et Cellulaire, Unité Propre de Recherche 9021, Centre National de la Recherche Scientifique, Strasbourg, France
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Wong H, Bowie JH, Carver JA. The solution structure and activity of caerin 1.1, an antimicrobial peptide from the Australian green tree frog, Litoria splendida. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 247:545-57. [PMID: 9266696 DOI: 10.1111/j.1432-1033.1997.00545.x] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Caerin 1.1 is one of the major antimicrobial peptides isolated from the skin of the Australian green tree frog, Litoria splendida. Two-dimensional 1H-1H and 1H-13C NMR spectroscopy in trifluoroethanol/H2O (50:50, by vol.) have been used to assign the 1H and 13C-NMR spectra of this 25-amino-acid peptide. From an examination of these data, and using distance geometry and molecular dynamics calculations, the solution conformation of caerin 1.1 has been determined. The peptide adopts two well-defined helices from Leu2 to Lys11 and from Val17 to His24 separated by a region of less-defined helicity and greater flexibility. Overall, the peptide has a distinct amphipathic charge distribution. The solution structure of caerin 1.1 is compared with activity data against a variety of micro-organisms for the parent peptide and some naturally occurring and synthetic variants of caerin 1.1. The structural and activity data are consistent with caerin 1.1 interacting with membranes in a similar manner to other antimicrobial peptides, i.e. via a carpet-like mechanism whereby the individual peptides aggregate in a helical manner and orient themselves parallel to the membrane in a sheet-like arrangement [Shai, Y. (1995) Trends Biochem. Sci. 20, 460-464].
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Affiliation(s)
- H Wong
- Industrial Research Limited, Lower Hutt, New Zealand
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