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Jungholm O, Trkulja C, Moche M, Srinivasa SP, Christakopoulou MN, Davidson M, Reymer A, Jardemark K, Fogaça RL, Ashok A, Jeffries G, Ampah-Korsah H, Strandback E, Andréll J, Nyman T, Nouairia G, Orwar O. Novel druggable space in human KRAS G13D discovered using structural bioinformatics and a P-loop targeting monoclonal antibody. Sci Rep 2024; 14:19656. [PMID: 39179604 PMCID: PMC11344056 DOI: 10.1038/s41598-024-70217-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 08/13/2024] [Indexed: 08/26/2024] Open
Abstract
KRAS belongs to a family of small GTPases that act as binary switches upstream of several signalling cascades, controlling proliferation and survival of cells. Mutations in KRAS drive oncogenesis, especially in pancreatic, lung, and colorectal cancers (CRC). Although historic attempts at targeting mutant KRAS with small molecule inhibitors have proven challenging, there are recent successes with the G12C, and G12D mutations. However, clinically important RAS mutations such as G12V, G13D, Q61L, and A146T, remain elusive drug targets, and insights to their structural landscape is of critical importance to develop novel, and effective therapeutic concepts. We present a fully open, P-loop exposing conformer of KRAS G13D by X-ray crystallography at 1.4-2.4 Å resolution in Mg2+-free phosphate and malonate buffers. The G13D conformer has the switch-I region displaced in an upright position leaving the catalytic core fully exposed. To prove that this state is druggable, we developed a P-loop-targeting monoclonal antibody (mAb). The mAb displayed high-affinity binding to G13D and was shown using high resolution fluorescence microscopy to be spontaneously taken up by G13D-mutated HCT 116 cells (human CRC derived) by macropinocytosis. The mAb inhibited KRAS signalling in phosphoproteomic and genomic studies. Taken together, the data propose novel druggable space of G13D that is reachable in the cellular context. It is our hope that these findings will stimulate attempts to drug this fully open state G13D conformer using mAbs or other modalities.
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Affiliation(s)
- Oscar Jungholm
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Carolina Trkulja
- Oblique Therapeutics AB, 41346, Gothenburg, Sweden
- Fluicell AB, Flöjelbergsgatan 8C, 431 37, Mölndal, Sweden
| | - Martin Moche
- Protein Science Facility, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Sreesha P Srinivasa
- Oblique Therapeutics AB, 41346, Gothenburg, Sweden
- Manipal Center for Biotherapeutics Research, Manipal Academy of Higher Education, Manipal, India
| | | | - Max Davidson
- Oblique Therapeutics AB, 41346, Gothenburg, Sweden
| | - Anna Reymer
- Oblique Therapeutics AB, 41346, Gothenburg, Sweden
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30, Gothenburg, Sweden
| | - Kent Jardemark
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | | | | | - Gavin Jeffries
- Fluicell AB, Flöjelbergsgatan 8C, 431 37, Mölndal, Sweden
| | - Henry Ampah-Korsah
- Protein Science Facility, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Emilia Strandback
- Protein Science Facility, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Juni Andréll
- Protein Science Facility, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Tomas Nyman
- Protein Science Facility, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Ghada Nouairia
- Department of Medicine Huddinge, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Owe Orwar
- Oblique Therapeutics AB, 41346, Gothenburg, Sweden.
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77, Stockholm, Sweden.
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Di Mambro T, Vanzolini T, Bianchi M, Crinelli R, Canonico B, Tasini F, Menotta M, Magnani M. Development and in vitro characterization of a humanized scFv against fungal infections. PLoS One 2022; 17:e0276786. [PMID: 36315567 PMCID: PMC9621433 DOI: 10.1371/journal.pone.0276786] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 10/14/2022] [Indexed: 01/24/2023] Open
Abstract
The resistance and the birth of new intrinsic and multidrug-resistant pathogenic species like C. auris is creating great concern in the antifungal world. Given the limited drug arsenal and the lack of effectiveness of the available compounds, there is an urgent need for innovative approaches. The murine mAb 2G8 was humanized and engineered in silico to develop a single-chain fragment variable (hscFv) antibody against β-1,3-glucans which was then expressed in E. coli. Among the recombinant proteins developed, a soluble candidate with high stability and affinity was obtained. This selected protein is VL-linker-VH oriented, and it is characterized by the presence of two ubiquitin monomers at the N-terminus and a His tag at the C-terminus. This construct, Ub2-hscFv-His, guaranteed stability, solubility, efficient purification and satisfactory recovery of the recombinant product. HscFv can bind β-1,3-glucans both as coated antigens and on C. auris and C. albicans cells similarly to its murine parental and showed long stability and retention of binding ability when stored at 4°, -20° and -80° C. Furthermore, it was efficient in enhancing the antifungal activity of drugs caspofungin and amphotericin B against C. auris. The use of biological drugs as antifungals is limited; here we present a promising hscFv which has the potential to be useful in combination with currently available antifungal drugs.
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Affiliation(s)
| | - Tania Vanzolini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
- * E-mail:
| | - Marzia Bianchi
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Rita Crinelli
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Barbara Canonico
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Filippo Tasini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Michele Menotta
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Mauro Magnani
- Diatheva s.r.l., Cartoceto, Italy
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
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Peplau E, De Rose F, Eichinger A, Reder S, Mittelhäuser M, Scafetta G, Schwaiger M, Weber WA, Bartolazzi A, D'Alessandria C, Skerra A. Effective rational humanization of a PASylated anti-galectin-3 Fab for the sensitive PET imaging of thyroid cancer in vivo. Sci Rep 2021; 11:7358. [PMID: 33795750 PMCID: PMC8016950 DOI: 10.1038/s41598-021-86641-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/17/2021] [Indexed: 02/01/2023] Open
Abstract
The lack of a non-invasive test for malignant thyroid nodules makes the diagnosis of thyroid cancer (TC) challenging. Human galectin-3 (hGal3) has emerged as a promising target for medical TC imaging and diagnosis because of its exclusive overexpression in malignant thyroid tissues. We previously developed a human-chimeric αhGal3 Fab fragment derived from the rat monoclonal antibody (mAb) M3/38 with optimized clearance characteristics using PASylation technology. Here, we describe the elucidation of the hGal3 epitope recognized by mAb M3/38, X-ray crystallographic analysis of its complex with the chimeric Fab and, based on the three-dimensional structure, the rational humanization of the Fab by CDR grafting. Four CDR-grafted versions were designed using structurally most closely related fully human immunoglobulin VH/VL regions of which one-employing the acceptor framework regions of the HIV-1 neutralizing human antibody m66-showed the highest antigen affinity. By introducing two additional back-mutations to the rodent donor sequence, an affinity toward hGal3 indistinguishable from the chimeric Fab was achieved (KD = 0.34 ± 0.02 nM in SPR). The PASylated humanized Fab was site-specifically labelled with the fluorescent dye Cy7 and applied for the immuno-histochemical staining of human tissue sections representative for different TCs. The same protein was conjugated with the metal chelator Dfo, followed by radiolabelling with 89Zr(IV). The resulting protein tracer allowed the highly sensitive and specific PET/CT imaging of orthotopic tumors in mice, which was confirmed by quantitative analysis of radiotracer accumulation. Thus, the PASylated humanized αhGal3 Fab offers clinical potential for the diagnostic imaging of TC.
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Affiliation(s)
- Emanuel Peplau
- Lehrstuhl für Biologische Chemie, Technische Universität München, 85354, Freising (Weihenstephan), Germany
| | - Francesco De Rose
- Klinikum rechts der Isar, Nuclear Medicine Department, Technical University Munich, Ismaninger Str. 22, 81675, Munich, Germany
| | - Andreas Eichinger
- Lehrstuhl für Biologische Chemie, Technische Universität München, 85354, Freising (Weihenstephan), Germany
| | - Sybille Reder
- Klinikum rechts der Isar, Nuclear Medicine Department, Technical University Munich, Ismaninger Str. 22, 81675, Munich, Germany
| | - Markus Mittelhäuser
- Klinikum rechts der Isar, Nuclear Medicine Department, Technical University Munich, Ismaninger Str. 22, 81675, Munich, Germany
| | - Giorgia Scafetta
- Pathology Research Laboratory, Sant'Andrea Hospital, University Sapienza, via di Grottarossa 1035, 00189, Rome, Italy
| | - Markus Schwaiger
- Klinikum rechts der Isar, Nuclear Medicine Department, Technical University Munich, Ismaninger Str. 22, 81675, Munich, Germany
| | - Wolfgang A Weber
- Klinikum rechts der Isar, Nuclear Medicine Department, Technical University Munich, Ismaninger Str. 22, 81675, Munich, Germany
| | - Armando Bartolazzi
- Pathology Research Laboratory, Cancer Center Karolinska, Karolinska Hospital, 17176, Stockholm, Sweden
- Pathology Research Laboratory, Sant'Andrea Hospital, University Sapienza, via di Grottarossa 1035, 00189, Rome, Italy
| | - Calogero D'Alessandria
- Klinikum rechts der Isar, Nuclear Medicine Department, Technical University Munich, Ismaninger Str. 22, 81675, Munich, Germany
| | - Arne Skerra
- Lehrstuhl für Biologische Chemie, Technische Universität München, 85354, Freising (Weihenstephan), Germany.
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Fernández-Quintero ML, Math BA, Loeffler JR, Liedl KR. Transitions of CDR-L3 Loop Canonical Cluster Conformations on the Micro-to-Millisecond Timescale. Front Immunol 2019; 10:2652. [PMID: 31803187 PMCID: PMC6877499 DOI: 10.3389/fimmu.2019.02652] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 10/25/2019] [Indexed: 01/02/2023] Open
Abstract
Sequence and structural diversity of antibodies are concentrated on six hypervariable loops, also known as the complementarity determining regions (CDRs). Five of six antibody CDR loops presumably adopt a so-called canonical structure out of a limited number of conformations. However, here we show for four antibody CDR-L3 loops differing in length and sequence, that each loop undergoes conformational transitions between different canonical structures. By extensive sampling in combination with Markov-state models we reconstruct the kinetics and probabilities of the transitions between canonical structures. Additionally, for these four CDR-L3 loops, we identify all relevant conformations in solution. Thereby we extend the model of static canonical structures to a dynamic conformational ensemble as a new paradigm in the field of antibody structure design.
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Affiliation(s)
| | | | | | - Klaus R. Liedl
- Center for Molecular Biosciences Innsbruck (CMBI), Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
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Almagro JC, Teplyakov A, Luo J, Sweet RW, Kodangattil S, Hernandez-Guzman F, Gilliland GL. Second antibody modeling assessment (AMA-II). Proteins 2014; 82:1553-62. [PMID: 24668560 DOI: 10.1002/prot.24567] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/18/2014] [Accepted: 03/19/2014] [Indexed: 01/07/2023]
Abstract
To assess the state of the art in antibody 3D modeling, 11 unpublished high-resolution x-ray Fab crystal structures from diverse species and covering a wide range of antigen-binding site conformations were used as a benchmark to compare Fv models generated by seven structure prediction methodologies. The participants included: Accerlys Inc, Chemical Computer Group (CCG), Schrodinger, Jeff Gray's lab at John Hopkins University, Macromoltek, Astellas Pharma/Osaka University and Prediction of ImmunoGlobulin Structure (PIGS). The sequences of benchmark structures were submitted to the modelers and PIGS, and a set of models were generated for each structure. We provide here an overview of the organization, participants and main results of this second antibody modeling assessment (AMA-II). Also, we compare the results with the first antibody assessment published in this journal (Almagro et al., 2011;79:3050).
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Affiliation(s)
- Juan C Almagro
- CTI Boston, Pfizer Inc., 3 Blackfan Circle, 18 Floor, Boston, MA, 02115
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Teplyakov A, Gilliland GL. Canonical structures of short CDR-L3 in antibodies. Proteins 2014; 82:1668-73. [PMID: 24623659 PMCID: PMC4260120 DOI: 10.1002/prot.24559] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 02/27/2014] [Accepted: 03/06/2014] [Indexed: 12/14/2022]
Abstract
Despite sequence diversity, five out of six hypervariable loops in antibodies assume a limited number of conformations called canonical structures. Their correct identification is essential for successful prediction of antibody structure. This in turn requires regular updates of the classification of canonical structures to match the expanding experimental database. Antibodies with the eight-residue CDR-L3 represent the second most common type of antibodies after those with the nine-residue CDR-L3. We have analyzed all crystal structures of Fab and Fv with the eight-residue CDR-L3 and identified three major canonical structures covering 82% of a nonredundant set. In most cases, the canonical structure is defined by the absence or presence and position of a proline residue within the CDR. Proteins 2014; 82:1668–1673. © 2014 Wiley Periodicals, Inc.
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Affiliation(s)
- Alexey Teplyakov
- Biotechnology Center of Excellence, Janssen Research and Development, LLC, Spring House, Pennsylvania, 19477
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