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Mishra AK, Ye T, Banday S, Thakare RP, Su CTT, Pham NNH, Ali A, Kulshreshtha A, Chowdhury SR, Simone TM, Hu K, Zhu LJ, Eisenhaber B, Deibler SK, Simin K, Thompson PR, Kelliher MA, Eisenhaber F, Malonia SK, Green MR. Targeting the GPI transamidase subunit GPAA1 abrogates the CD24 immune checkpoint in ovarian cancer. Cell Rep 2024; 43:114041. [PMID: 38573857 DOI: 10.1016/j.celrep.2024.114041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 01/25/2024] [Accepted: 03/19/2024] [Indexed: 04/06/2024] Open
Abstract
CD24 is frequently overexpressed in ovarian cancer and promotes immune evasion by interacting with its receptor Siglec10, present on tumor-associated macrophages, providing a "don't eat me" signal that prevents targeting and phagocytosis by macrophages. Factors promoting CD24 expression could represent novel immunotherapeutic targets for ovarian cancer. Here, using a genome-wide CRISPR knockout screen, we identify GPAA1 (glycosylphosphatidylinositol anchor attachment 1), a factor that catalyzes the attachment of a glycosylphosphatidylinositol (GPI) lipid anchor to substrate proteins, as a positive regulator of CD24 cell surface expression. Genetic ablation of GPAA1 abolishes CD24 cell surface expression, enhances macrophage-mediated phagocytosis, and inhibits ovarian tumor growth in mice. GPAA1 shares structural similarities with aminopeptidases. Consequently, we show that bestatin, a clinically advanced aminopeptidase inhibitor, binds to GPAA1 and blocks GPI attachment, resulting in reduced CD24 cell surface expression, increased macrophage-mediated phagocytosis, and suppressed growth of ovarian tumors. Our study highlights the potential of targeting GPAA1 as an immunotherapeutic approach for CD24+ ovarian cancers.
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Affiliation(s)
- Alok K Mishra
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA.
| | - Tianyi Ye
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Shahid Banday
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Ritesh P Thakare
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Chinh Tran-To Su
- Bioinformatics Institute (BII), Agency for Science, Technology, and Research (A(∗)STAR), 30 Biopolis Street, Matrix, #07-01, Singapore 138671, Singapore
| | - Ngoc N H Pham
- Faculty of Biology and Biotechnology, University of Science, Vietnam National University, 227 Nguyen Van Cu Street, District 5, Ho Chi Minh City, Vietnam
| | - Amjad Ali
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Ankur Kulshreshtha
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Shreya Roy Chowdhury
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Tessa M Simone
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Kai Hu
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Lihua Julie Zhu
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA; Program in Molecular Medicine and Department of Genomics and Computational Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Birgit Eisenhaber
- Bioinformatics Institute (BII), Agency for Science, Technology, and Research (A(∗)STAR), 30 Biopolis Street, Matrix, #07-01, Singapore 138671, Singapore; Lausitz Advanced Scientific Applications (LASA) gGmbH, Straße der Einheit 2-24, 02943 Weißwasser, Germany
| | - Sara K Deibler
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Karl Simin
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Paul R Thompson
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Michelle A Kelliher
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Frank Eisenhaber
- Bioinformatics Institute (BII), Agency for Science, Technology, and Research (A(∗)STAR), 30 Biopolis Street, Matrix, #07-01, Singapore 138671, Singapore; Lausitz Advanced Scientific Applications (LASA) gGmbH, Straße der Einheit 2-24, 02943 Weißwasser, Germany; School of Biological Sciences, Nanyang Technological University (NTU), 60 Nanyang Drive, Singapore 637551, Singapore.
| | - Sunil K Malonia
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA.
| | - Michael R Green
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
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Ling WL, Su CTT, Lua WH, Yeo JY, Poh JJ, Ng YL, Wipat A, Gan SKE. Variable-heavy (VH) families influencing IgA1&2 engagement to the antigen, FcαRI and superantigen proteins G, A, and L. Sci Rep 2022; 12:6510. [PMID: 35444201 PMCID: PMC9020155 DOI: 10.1038/s41598-022-10388-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 04/07/2022] [Indexed: 12/18/2022] Open
Abstract
Interest in IgA as an alternative antibody format has increased over the years with much remaining to be investigated in relation to interactions with immune cells. Considering the recent whole antibody investigations showing significant distal effects between the variable (V) and constant (C)- regions that can be mitigated by the hinge regions of both human IgA subtypes A1 and A2, we performed an in-depth mechanistic investigation using a panel of 28 IgA1s and A2s of both Trastuzumab and Pertuzumab models. FcαRI binding were found to be mitigated by the differing glycosylation patterns in IgA1 and 2 with contributions from the CDRs. On their interactions with antigen-Her2 and superantigens PpL, SpG and SpA, PpL was found to sterically hinder Her2 antigen binding with unexpected findings of IgAs binding SpG at the CH2-3 region alongside SpA interacting with IgAs at the CH1. Although the VH3 framework (FWR) is commonly used in CDR grafting, we found the VH1 framework (FWR) to be a possible alternative when grafting IgA1 and 2 owing to its stronger binding to antigen Her2 and weaker interactions to superantigen Protein L and A. These findings lay the foundation to understanding the interactions between IgAs and microbial superantigens, and also guide the engineering of IgAs for future antibody applications and targeting of superantigen-producing microbes.
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Affiliation(s)
- Wei-Li Ling
- Antibody & Product Development Lab, Experimental Drug Development Centre, Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.,Newcastle University Singapore, Singapore, Singapore
| | - Chinh Tran-To Su
- Antibody & Product Development Lab, Experimental Drug Development Centre, Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Wai-Heng Lua
- Antibody & Product Development Lab, Experimental Drug Development Centre, Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Joshua Yi Yeo
- Antibody & Product Development Lab, Experimental Drug Development Centre, Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Jun-Jie Poh
- Antibody & Product Development Lab, Experimental Drug Development Centre, Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Yuen-Ling Ng
- Newcastle University Singapore, Singapore, Singapore
| | - Anil Wipat
- School of Computing, Newcastle University, Newcastle upon Tyne, UK
| | - Samuel Ken-En Gan
- Antibody & Product Development Lab, Experimental Drug Development Centre, Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore. .,James Cook University, Singapore, Singapore. .,Zhejiang Bioinformatics International Science and Technology Cooperation Center, Wenzhou-Kean University, Wenzhou, Zhejiang Province, China. .,Wenzhou Municipal Key Lab of Applied Biomedical and Biopharmaceutical Informatics, Wenzhou-Kean University, Wenzhou, Zhejiang Province, China.
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Su CTT, Lua WH, Poh JJ, Ling WL, Yeo JY, Gan SKE. Molecular Insights of Nickel Binding to Therapeutic Antibodies as a Possible New Antibody Superantigen. Front Immunol 2021; 12:676048. [PMID: 34305906 PMCID: PMC8296638 DOI: 10.3389/fimmu.2021.676048] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/24/2021] [Indexed: 11/21/2022] Open
Abstract
The binding of nickel by immune proteins can manifest as Type IV contact dermatitis (Ni-specific T cells mediated) and less frequently as Type I hypersensitivity with both mechanisms remaining unknown to date. Since there are reports of patients co-manifesting the two hypersensitivities, a common mechanism may underlie both the TCR and IgE nickel binding. Focusing on Trastuzumab and Pertuzumab IgE variants as serendipitous investigation models, we found Ni-NTA interactions independent of Her2 binding to be due to glutamine stretches. These stretches are both Ni-inducible and in fixed pockets at the antibody complementarity-determining regions (CDRs) and framework regions (FWRs) of both the antibody heavy and light chains with influence from the heavy chain constant region. Comparisons with TCRs structures revealed similar interactions, demonstrating the possible underlying mechanism in selecting for Ni-binding IgEs and TCRs respectively. With the elucidation of the interaction, future therapeutic antibodies could also be sagaciously engineered to utilize such nickel binding for biotechnological purposes.
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Affiliation(s)
- Chinh Tran-To Su
- Antibody & Product Development Lab, Experimental Drug Development Centre, Bioinformatics Institute, Agency for Science, Technology, and Research (ASTAR), Singapore, Singapore
| | - Wai-Heng Lua
- Antibody & Product Development Lab, Experimental Drug Development Centre, Bioinformatics Institute, Agency for Science, Technology, and Research (ASTAR), Singapore, Singapore
| | - Jun-Jie Poh
- Antibody & Product Development Lab, Experimental Drug Development Centre, Bioinformatics Institute, Agency for Science, Technology, and Research (ASTAR), Singapore, Singapore
| | - Wei-Li Ling
- Antibody & Product Development Lab, Experimental Drug Development Centre, Bioinformatics Institute, Agency for Science, Technology, and Research (ASTAR), Singapore, Singapore
| | - Joshua Yi Yeo
- Antibody & Product Development Lab, Experimental Drug Development Centre, Bioinformatics Institute, Agency for Science, Technology, and Research (ASTAR), Singapore, Singapore
| | - Samuel Ken-En Gan
- Antibody & Product Development Lab, Experimental Drug Development Centre, Bioinformatics Institute, Agency for Science, Technology, and Research (ASTAR), Singapore, Singapore.,James Cook University, Singapore, Singapore.,APD SKEG Pte Ltd, Singapore, Singapore
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Chan KF, Su CTT, Krah A, Phua SX, Yeo JY, Ling WL, Bond PJ, Gan SKE. An Alternative HIV-1 Non-Nucleoside Reverse Transcriptase Inhibition Mechanism: Targeting the p51 Subunit. Molecules 2020; 25:E5902. [PMID: 33322154 PMCID: PMC7763519 DOI: 10.3390/molecules25245902] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 12/09/2020] [Accepted: 12/11/2020] [Indexed: 01/08/2023] Open
Abstract
The ongoing development of drug resistance in HIV continues to push for the need of alternative drug targets in inhibiting HIV. One such target is the Reverse transcriptase (RT) enzyme which is unique and critical in the viral life cycle-a rational target that is likely to have less off-target effects in humans. Serendipitously, we found two chemical scaffolds from the National Cancer Institute (NCI) Diversity Set V that inhibited HIV-1 RT catalytic activity. Computational structural analyses and subsequent experimental testing demonstrated that one of the two chemical scaffolds binds to a novel location in the HIV-1 RT p51 subunit, interacting with residue Y183, which has no known association with previously reported drug resistance. This finding supports the possibility of a novel druggable site on p51 for a new class of non-nucleoside RT inhibitors that may inhibit HIV-1 RT allosterically. Although inhibitory activity was shown experimentally to only be in the micromolar range, the scaffolds serve as a proof-of-concept of targeting the HIV RT p51 subunit, with the possibility of medical chemistry methods being applied to improve inhibitory activity towards more effective drugs.
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Affiliation(s)
- Kwok-Fong Chan
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore; (K.-F.C.); (C.T.-T.S.); (A.K.); (S.-X.P.); (J.Y.Y.); (W.-L.L.); (P.J.B.)
| | - Chinh Tran-To Su
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore; (K.-F.C.); (C.T.-T.S.); (A.K.); (S.-X.P.); (J.Y.Y.); (W.-L.L.); (P.J.B.)
- Experimental Drug Development Centre, A*STAR, 10 Biopolis Road Chromos #05-01, Singapore 138670, Singapore
| | - Alexander Krah
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore; (K.-F.C.); (C.T.-T.S.); (A.K.); (S.-X.P.); (J.Y.Y.); (W.-L.L.); (P.J.B.)
| | - Ser-Xian Phua
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore; (K.-F.C.); (C.T.-T.S.); (A.K.); (S.-X.P.); (J.Y.Y.); (W.-L.L.); (P.J.B.)
| | - Joshua Yi Yeo
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore; (K.-F.C.); (C.T.-T.S.); (A.K.); (S.-X.P.); (J.Y.Y.); (W.-L.L.); (P.J.B.)
- Experimental Drug Development Centre, A*STAR, 10 Biopolis Road Chromos #05-01, Singapore 138670, Singapore
| | - Wei-Li Ling
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore; (K.-F.C.); (C.T.-T.S.); (A.K.); (S.-X.P.); (J.Y.Y.); (W.-L.L.); (P.J.B.)
- Experimental Drug Development Centre, A*STAR, 10 Biopolis Road Chromos #05-01, Singapore 138670, Singapore
| | - Peter J. Bond
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore; (K.-F.C.); (C.T.-T.S.); (A.K.); (S.-X.P.); (J.Y.Y.); (W.-L.L.); (P.J.B.)
| | - Samuel Ken-En Gan
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore; (K.-F.C.); (C.T.-T.S.); (A.K.); (S.-X.P.); (J.Y.Y.); (W.-L.L.); (P.J.B.)
- Experimental Drug Development Centre, A*STAR, 10 Biopolis Road Chromos #05-01, Singapore 138670, Singapore
- p53 Laboratory, A*STAR, 8A Biomedical Grove, #06-04/05 Neuros/Immunos, Singapore 138648, Singapore
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Ling WL, Su CTT, Lua WH, Poh JJ, Ng YL, Wipat A, Gan SKE. Essentially Leading Antibody Production: An Investigation of Amino Acids, Myeloma, and Natural V-Region Signal Peptides in Producing Pertuzumab and Trastuzumab Variants. Front Immunol 2020; 11:604318. [PMID: 33365032 PMCID: PMC7750424 DOI: 10.3389/fimmu.2020.604318] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/05/2020] [Indexed: 11/29/2022] Open
Abstract
Boosting the production of recombinant therapeutic antibodies is crucial in both academic and industry settings. In this work, we investigated the usage of varying signal peptides by antibody V-genes and their roles in recombinant transient production, systematically comparing myeloma and the native signal peptides of both heavy and light chains in 168 antibody permutation variants. We found that amino acids count and types (essential or non-essential) were important factors in a logistic regression equation model for predicting transient co-transfection protein production rates. Deeper analysis revealed that the culture media were often incomplete and that the supplementation of essential amino acids can improve the recombinant protein yield. While these findings are derived from transient HEK293 expression, they also provide insights to the usage of the large repertoire of antibody signal peptides, where by varying the number of specific amino acids in the signal peptides attached to the variable regions, bottlenecks in amino acid availability can be mitigated.
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Affiliation(s)
- Wei-Li Ling
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Newcastle Research and Innovation Institute (NewRIIS), Singapore, Singapore
- Experimental Drug Development Centre, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Chinh Tran-To Su
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Experimental Drug Development Centre, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Wai-Heng Lua
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Jun-Jie Poh
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Yuen-Ling Ng
- Newcastle Research and Innovation Institute (NewRIIS), Singapore, Singapore
| | - Anil Wipat
- School of Computing, Newcastle University, Singapore, Singapore
| | - Samuel Ken-En Gan
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Experimental Drug Development Centre, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
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Su CTT, Sinha S, Eisenhaber B, Eisenhaber F. Structural modelling of the lumenal domain of human GPAA1, the metallo-peptide synthetase subunit of the transamidase complex, reveals zinc-binding mode and two flaps surrounding the active site. Biol Direct 2020; 15:14. [PMID: 32993792 PMCID: PMC7522609 DOI: 10.1186/s13062-020-00266-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/30/2020] [Indexed: 02/01/2023] Open
Abstract
Background The transamidase complex is a molecular machine in the endoplasmic reticulum of eukaryotes that attaches a glycosylphosphatidylinositol (GPI) lipid anchor to substrate proteins after cleaving a C-terminal propeptide with a defined sequence signal. Its five subunits are very hydrophobic; thus, solubility, heterologous expression and complex reconstruction are difficult. Therefore, theoretical approaches are currently the main source of insight into details of 3D structure and of the catalytic process. Results In this work, we generated model 3D structures of the lumenal domain of human GPAA1, the M28-type metallo-peptide-synthetase subunit of the transamidase, including zinc ion and model substrate positions. In comparative molecular dynamics (MD) simulations of M28-type structures and our GPAA1 models, we estimated the metal ion binding energies with evolutionary conserved amino acid residues in the catalytic cleft. We find that canonical zinc binding sites 2 and 3 are strongest binders for Zn1 and, where a second zinc is available, sites 2 and 4 for Zn2. Zinc interaction of site 5 with Zn1 enhances upon substrate binding in structures with only one zinc. Whereas a previously studied glutaminyl cyclase structure, the best known homologue to GPAA1, binds only one zinc ion at the catalytic site, GPAA1 can sterically accommodate two. The M28-type metallopeptidases segregate into two independent branches with regard to one/two zinc ion binding modality in a phylogenetic tree where the GPAA1 family is closer to the joint origin of both groups. For GPAA1 models, MD studies revealed two large loops (flaps) surrounding the active site being involved in an anti-correlated, breathing-like dynamics. Conclusions In the light of combined sequence-analytic and phylogenetic arguments as well as 3D structural modelling results, GPAA1 is most likely a single zinc ion metallopeptidase. Two large flaps environ the catalytic site restricting access to large substrates. Reviewers This article was reviewed by Thomas Dandekar (MD) and Michael Gromiha.
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Affiliation(s)
- Chinh Tran-To Su
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, # 07-01, Matrix, Singapore, 138671, Singapore
| | - Swati Sinha
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, # 07-01, Matrix, Singapore, 138671, Singapore
| | - Birgit Eisenhaber
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, # 07-01, Matrix, Singapore, 138671, Singapore.
| | - Frank Eisenhaber
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, # 07-01, Matrix, Singapore, 138671, Singapore. .,School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore.
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Su CTT, Koh DWS, Gan SKE. Reviewing HIV-1 Gag Mutations in Protease Inhibitors Resistance: Insights for Possible Novel Gag Inhibitor Designs. Molecules 2019; 24:molecules24183243. [PMID: 31489889 PMCID: PMC6767625 DOI: 10.3390/molecules24183243] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 09/03/2019] [Accepted: 09/04/2019] [Indexed: 12/31/2022] Open
Abstract
HIV protease inhibitors against the viral protease are often hampered by drug resistance mutations in protease and in the viral substrate Gag. To overcome this drug resistance and inhibit viral maturation, targeting Gag alongside protease rather than targeting protease alone may be more efficient. In order to successfully inhibit Gag, understanding of its drug resistance mutations and the elicited structural changes on protease binding needs to be investigated. While mutations on Gag have already been mapped to protease inhibitor resistance, there remain many mutations, particularly the non-cleavage mutations, that are not characterized. Through structural studies to unravel how Gag mutations contributes to protease drug resistance synergistically, it is thus possible to glean insights to design novel Gag inhibitors. In this review, we discuss the structural role of both novel and previously reported Gag mutations in PI resistance, and how new Gag inhibitors can be designed.
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Affiliation(s)
- Chinh Tran-To Su
- Antibody & Product Development Lab, Bioinformatics Institute, A*STAR, Singapore 138671, Singapore
| | - Darius Wen-Shuo Koh
- Antibody & Product Development Lab, Bioinformatics Institute, A*STAR, Singapore 138671, Singapore
| | - Samuel Ken-En Gan
- Antibody & Product Development Lab, Bioinformatics Institute, A*STAR, Singapore 138671, Singapore.
- p53 Laboratory, A*STAR, Singapore 138648, Singapore.
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Lua WH, Su CTT, Yeo JY, Poh JJ, Ling WL, Phua SX, Gan SKE. Role of the IgE variable heavy chain in FcεRIα and superantigen binding in allergy and immunotherapy. J Allergy Clin Immunol 2019; 144:514-523.e5. [DOI: 10.1016/j.jaci.2019.03.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 03/25/2019] [Accepted: 03/29/2019] [Indexed: 01/17/2023]
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Phua SX, Chan KF, Su CTT, Poh JJ, Gan SKE. Perspective: The promises of a holistic view of proteins-impact on antibody engineering and drug discovery. Biosci Rep 2019; 39:BSR20181958. [PMID: 30630879 PMCID: PMC6398899 DOI: 10.1042/bsr20181958] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 12/27/2018] [Accepted: 01/09/2019] [Indexed: 12/23/2022] Open
Abstract
The reductionist approach is prevalent in biomedical science. However, increasing evidence now shows that biological systems cannot be simply considered as the sum of its parts. With experimental, technological, and computational advances, we can now do more than view parts in isolation, thus we propose that an increasing holistic view (where a protein is investigated as much as a whole as possible) is now timely. To further advocate this, we review and discuss several studies and applications involving allostery, where distant protein regions can cross-talk to influence functionality. Therefore, we believe that an increasing big picture approach holds great promise, particularly in the areas of antibody engineering and drug discovery in rational drug design.
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Affiliation(s)
- Ser-Xian Phua
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Kwok-Fong Chan
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Chinh Tran-To Su
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Jun-Jie Poh
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore
- APD SKEG Pte Ltd, Singapore
| | - Samuel Ken-En Gan
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore
- APD SKEG Pte Ltd, Singapore
- p53 Laboratory, Agency for Science, Technology and Research (A*STAR), Singapore
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Chiang RZH, Gan SKE, Su CTT. A computational study for rational HIV-1 non-nucleoside reverse transcriptase inhibitor selection and the discovery of novel allosteric pockets for inhibitor design. Biosci Rep 2018; 38:BSR20171113. [PMID: 29437904 PMCID: PMC5835713 DOI: 10.1042/bsr20171113] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 01/29/2018] [Accepted: 01/29/2018] [Indexed: 12/15/2022] Open
Abstract
HIV drug resistant mutations that render the current Highly Active Anti-Retroviral Therapy (HAART) cocktail drugs ineffective are increasingly reported. To study the mechanisms of these mutations in conferring drug resistance, we computationally analyzed 14 reverse transcriptase (RT) structures of HIV-1 on the following parameters: drug-binding pocket volume, allosteric effects caused by the mutations, and structural thermal stability. We constructed structural correlation-based networks of the mutant RT-drug complexes and the analyses support the use of efavirenz (EFZ) as the first-line drug, given that cross-resistance is least likely to develop from EFZ-resistant mutations. On the other hand, rilpivirine (RPV)-resistant mutations showed the highest cross-resistance to the other non-nucleoside RT inhibitors. With significant drug cross-resistance associated with the known allosteric drug-binding site, there is a need to identify new allosteric druggable sites in the structure of RT. Through computational analyses, we found such a novel druggable pocket on the HIV-1 RT structure that is comparable with the original allosteric drug site, opening the possibility to the design of new inhibitors.
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Affiliation(s)
- Ron Zhi-Hui Chiang
- Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR), Singapore 138671
| | - Samuel Ken-En Gan
- Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR), Singapore 138671
- p53 Laboratory, Agency for Science, Technology, and Research (A*STAR), Singapore 138648
| | - Chinh Tran-To Su
- Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR), Singapore 138671
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Su CTT, Kwoh CK, Verma CS, Gan SKE. Modeling the full length HIV-1 Gag polyprotein reveals the role of its p6 subunit in viral maturation and the effect of non-cleavage site mutations in protease drug resistance. J Biomol Struct Dyn 2017; 36:4366-4377. [PMID: 29237328 DOI: 10.1080/07391102.2017.1417160] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
HIV polyprotein Gag is increasingly found to contribute to protease inhibitor resistance. Despite its role in viral maturation and in developing drug resistance, there remain gaps in the knowledge of the role of certain Gag subunits (e.g. p6), and that of non-cleavage mutations in drug resistance. As p6 is flexible, it poses a problem for structural experiments, and is hence often omitted in experimental Gag structural studies. Nonetheless, as p6 is an indispensable component for viral assembly and maturation, we have modeled the full length Gag structure based on several experimentally determined constraints and studied its structural dynamics. Our findings suggest that p6 can mechanistically modulate Gag conformations. In addition, the full length Gag model reveals that allosteric communication between the non-cleavage site mutations and the first Gag cleavage site could possibly result in protease drug resistance, particularly in the absence of mutations in Gag cleavage sites. Our study provides a mechanistic understanding to the structural dynamics of HIV-1 Gag, and also proposes p6 as a possible drug target in anti-HIV therapy.
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Affiliation(s)
- Chinh Tran-To Su
- a Bioinformatics Institute , Agency for Science, Technology, and Research (A*STAR) , Singapore 138671 , Singapore
| | - Chee-Keong Kwoh
- b School of Computer Science and Engineering , Nanyang Technological University , Singapore 639798 , Singapore
| | - Chandra Shekhar Verma
- a Bioinformatics Institute , Agency for Science, Technology, and Research (A*STAR) , Singapore 138671 , Singapore
| | - Samuel Ken-En Gan
- a Bioinformatics Institute , Agency for Science, Technology, and Research (A*STAR) , Singapore 138671 , Singapore.,c p53 Laboratory , Agency for Science, Technology, and Research (A*STAR) , Singapore 138648 , Singapore
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Su CTT, Ling WL, Lua WH, Poh JJ, Gan SKE. The role of Antibody Vκ Framework 3 region towards Antigen binding: Effects on recombinant production and Protein L binding. Sci Rep 2017. [PMID: 28630463 PMCID: PMC5476676 DOI: 10.1038/s41598-017-02756-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Antibody research has traditionally focused on heavy chains, often neglecting the important complementary role of light chains in antibody formation and secretion. In the light chain, the complementarity-determining region 3 (VL-CDR3) is specifically implicated in disease states. By modulating VL-CDR3 exposure on the scaffold through deletions in the framework region 3 (VL-FWR3), we further investigated the effects on secretion in recombinant production and antigen binding kinetics. Our random deletions of two residues in the VL-FWR3 of a Trastuzumab model showed that the single deletions could impact recombinant production without significant effect on Her2 binding. When both the selected residues were deleted, antibody secretion was additively decreased, and so was Her2 binding kinetics. Interestingly, we also found allosteric effects on the Protein L binding site at VL-FWR1 elicited by these deletions in VL- FWR3. Together, these findings demonstrate the importance of light chain FWR3 in antigen binding, recombinant production, and antibody purification using Protein L.
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Affiliation(s)
- Chinh Tran-To Su
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Wei-Li Ling
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Wai-Heng Lua
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Jun-Jie Poh
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Samuel Ken-En Gan
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore. .,p53 Laboratory, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
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Lua WH, Ling WL, Su CTT, Yeo JY, Verma CS, Eisenhaber B, Eisenhaber F, Gan SKE. Discovery of a novel splice variant of Fcar (CD89) unravels sequence segments necessary for efficient secretion: A story of bad signal peptides and good ones that nevertheless do not make it. Cell Cycle 2017; 16:457-467. [PMID: 28103138 PMCID: PMC5351921 DOI: 10.1080/15384101.2017.1281480] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
The IgA receptor, Fcar (CD89) consists of 5 sequence segments: 2 segments (S1, S2) forming the potential signal peptide, 2 extracellular EC domains that include the IgA binding site, and the transmembrane and cytoplasmic tail (TM/C) region. Numerous Fcar splice variants have been reported with various combinations of the sequence segments mentioned above. Here, we report a novel splice variant termed variant APD isolated from a healthy volunteer that lacks only the IgA-binding EC1 domain. Despite possessing the complete signal peptide S1+S2, the variant APD is only found in the intracellular space whereas the wild-type variant 1 is efficiently secreted and variant 4 leaks to the extracellular space. Further mutational experiments involving signal peptide replacements, cleavage site modifications, and studies on alternative isoforms demonstrate that despite the completeness of the signal peptide motif, the presence of the EC1 domain is essential for efficient extracellular export.
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Affiliation(s)
- Wai-Heng Lua
- a Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR) , Singapore
| | - Wei-Li Ling
- a Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR) , Singapore
| | - Chinh Tran-To Su
- a Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR) , Singapore
| | - Joshua Yi Yeo
- a Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR) , Singapore
| | - Chandra Shekhar Verma
- a Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR) , Singapore.,b Department of Biological Sciences , National University of Singapore (NUS) , Singapore.,c School of Biological Sciences, Nanyang Technological University (NTU) , Singapore
| | - Birgit Eisenhaber
- a Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR) , Singapore
| | - Frank Eisenhaber
- a Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR) , Singapore.,d School of Computer Engineering, Nanyang Technological University (NTU) , Singapore
| | - Samuel Ken-En Gan
- a Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR) , Singapore.,e p53 Laboratory, Agency for Science, Technology, and Research (A*STAR) , Singapore
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Su CTT, Ling WL, Lua WH, Haw YX, Gan SKE. Structural analyses of 2015-updated drug-resistant mutations in HIV-1 protease: an implication of protease inhibitor cross-resistance. BMC Bioinformatics 2016; 17:500. [PMID: 28155724 PMCID: PMC5259968 DOI: 10.1186/s12859-016-1372-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Background Strategies to control HIV for improving the quality of patient lives have been aided by the Highly Active Anti-Retroviral Therapy (HAART), which consists of a cocktail of inhibitors targeting key viral enzymes. Numerous new drugs have been developed over the past few decades but viral resistances to these drugs in the targeted viral enzymes are increasingly reported. Nonetheless the acquired mutations often reduce viral fitness and infectivity. Viral compensatory secondary-line mutations mitigate this loss of fitness, equipping the virus with a broad spectrum of resistance against these drugs. While structural understanding of the viral protease and its drug resistance mutations have been well established, the interconnectivity and development of structural cross-resistance remain unclear. This paper reports the structural analyses of recent clinical mutations on the drug cross-resistance effects from various protease and protease inhibitors (PIs) complexes. Methods Using the 2015 updated clinical HIV protease mutations, we constructed a structure-based correlation network and a minimum-spanning tree (MST) based on the following features: (i) topology of the PI-binding pocket, (ii) allosteric effects of the mutations, and (iii) protease structural stability. Results and conclusion Analyis of the network and the MST of dominant mutations conferring resistance to the seven PIs (Atazanavir-ATV, Darunavir-DRV, Indinavir-IDV, Lopinavir-LPV, Nelfinavir-NFV, Saquinavir-SQV, and Tipranavir-TPV) showed that cross-resistance can develop easily across NFV, SQV, LPV, IDV, and DRV, but not for ATV or TPV. Through estimation of the changes in vibrational entropies caused by each reported mutation, some secondary mutations were found to destabilize protease structure. Our findings provide an insight into the mechanism of PI cross-resistance and may also be useful in guiding the selection of PI in clinical treatment to delay the onset of cross drug resistance. Electronic supplementary material The online version of this article (doi:10.1186/s12859-016-1372-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chinh Tran-To Su
- Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR), Singapore, 138671, Singapore.
| | - Wei-Li Ling
- Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR), Singapore, 138671, Singapore
| | - Wai-Heng Lua
- Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR), Singapore, 138671, Singapore
| | - Yu-Xuan Haw
- Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR), Singapore, 138671, Singapore
| | - Samuel Ken-En Gan
- Bioinformatics Institute, Agency for Science, Technology, and Research (A*STAR), Singapore, 138671, Singapore. .,p53 Laboratory, Agency for Science, Technology, and Research (A*STAR), Singapore, 138648, Singapore.
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Tran-To Su C, Ouyang X, Zheng J, Kwoh CK. Structural analysis of the novel influenza A (H7N9) viral Neuraminidase interactions with current approved neuraminidase inhibitors Oseltamivir, Zanamivir, and Peramivir in the presence of mutation R289K. BMC Bioinformatics 2013; 14 Suppl 16:S7. [PMID: 24564719 PMCID: PMC3853198 DOI: 10.1186/1471-2105-14-s16-s7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background Since late March 2013, there has been another global health concern with a sudden wave of flu infections by a novel strain of avian influenza A (H7N9) virus in China. To-date, there have been more than 100 infections with 23 deaths. It is more worrying as this viral strain has never been detected in humans and only been found to be of low-pathogenicity. Currently, there are 3 effective neuraminidase inhibitors for this H7N9 virus strain, i.e. oseltamivir, zanamivir, and peramivir. These drugs have been used for treatment of the H7N9 influenza in China. However, how these inhibitors work and affect the binding cavity of the novel H7N9 neuraminidase in the presence of potential mutations has not been disclosed. In our study, we investigate steric effects and subsequently show the conformational restraints of the inhibitor-binding site of the non-mutated and mutated H7N9 neuraminidase structures to different drug compounds. Results Combination of molecular docking and Molecular Dynamics simulation reveal that zanamivir forms more favorable and stable complex than oseltamivir and peramivir when binding to the active site of the H7N9 neuraminidase. And it is likely that the novel influenza A (H7N9) virus adopts a higher probability to acquire resistance to peramivir than the other two inhibitors. Conformational changes induced by the mutation R289K causes loss of number of hydrogen bonds between the inhibitors and the H7N9 viral neuraminidase in 2 out of 3 complexes. In addition, our results of binding-affinity relationships of the 3 inhibitors with the viral neuraminidase proteins of previous pandemics (H1N1, H5N1) and the current novel H7N9 reflected the extent of binding effectiveness of the 3 inhibitors to the novel H7N9 neuraminidase. Conclusions The results are novel and specific for the A/Hangzhou/1/2013(H7N9) influenza strain. Furthermore, the protocol could be useful for further drug-binding analysis and prediction of future viral mutations to which the virus evolves through adaptation and acquires resistance to the current available drugs.
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