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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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Mirisola MG, Longo VD. Inactivation of Ymr1, Sjl2/3 phosphatases promotes stress resistance and longevity in wild type and Ras2G19V yeast. Biomed J 2024; 47:100694. [PMID: 38154617 PMCID: PMC10950826 DOI: 10.1016/j.bj.2023.100694] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 12/30/2023] Open
Abstract
In Saccharomyces cerevisiae, RAt Sarcoma (Ras) activity plays a central role in mediating the effect of glucose in decreasing stress resistance and longevity, with constitutive Ras activation mutations promoting cell growth and oncogenesis. Here, we used transposon mutagenesis in yeast to identify suppressors of the constitutively active Ras2G19V, orthologue of the KRASG12C mammalian oncogene. We identified mutations in Yeast Myotubularin Related (YMR1), SynaptoJanin-Like (SJL2) and SJL3 phosphatases, which target phosphatidylinositol phosphates, as the most potent suppressors of constitutive active Ras, able to reverse its effect on stress sensitization and sufficient to extend longevity. In sjl2 mutants, the staining of Ras-GTP switched from membrane-associated to a diffuse cytoplasmic staining, suggesting that it may block Ras activity by preventing its localization. Whereas expression of the Sjl2 PI 3,4,5 phosphatase mediated stress sensitization in both the Ras2G19V and wild type backgrounds, overexpression of the phosphatidylinositol 3 kinase VPS34 (Vacuolar Protein Sorting), promoted heat shock sensitization only in the Ras2G19V background, suggesting a complex relationship between different phosphatidylinositol and stress resistance. These results provide potential targets to inhibit the growth of cancer cells with constitutive Ras activity and link the glucose-dependent yeast pro-aging Ras signaling pathway to the well-established pro-aging PhosphoInositide 3-Kinase(PI3K) pathway in worms and other species raising the possibility that the conserved longevity effect of mutations in the PI3K-AKT (AK strain Transforming) pathway may involve inhibition of Ras signaling.
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Affiliation(s)
- M G Mirisola
- SteBiCeF Department, University of Palermo, Palermo, Italy.
| | - V D Longo
- IFOM, AIRC Institute of Molecular Oncology, Milan, Italy; Longevity Institute and Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA.
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