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Ketcham JM, Harwood SJ, Aranda R, Aloiau AN, Bobek BM, Briere DM, Burns AC, Caddell Haatveit K, Calinisan A, Clarine J, Elliott A, Engstrom LD, Gunn RJ, Ivetac A, Jones B, Kuehler J, Lawson JD, Nguyen N, Parker C, Pearson KE, Rahbaek L, Saechao B, Wang X, Waters A, Waters L, Watkins AH, Olson P, Smith CR, Christensen JG, Marx MA. Discovery of Pyridopyrimidinones that Selectively Inhibit the H1047R PI3Kα Mutant Protein. J Med Chem 2024; 67:4936-4949. [PMID: 38477582 PMCID: PMC10983000 DOI: 10.1021/acs.jmedchem.4c00078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/20/2024] [Accepted: 02/26/2024] [Indexed: 03/14/2024]
Abstract
The H1047R mutation of PIK3CA is highly prevalent in breast cancers and other solid tumors. Selectively targeting PI3KαH1047R over PI3KαWT is crucial due to the role that PI3KαWT plays in normal cellular processes, including glucose homeostasis. Currently, only one PI3KαH1047R-selective inhibitor has progressed into clinical trials, while three pan mutant (H1047R, H1047L, H1047Y, E542K, and E545K) selective PI3Kα inhibitors have also reached the clinical stage. Herein, we report the design and discovery of a series of pyridopyrimidinones that inhibit PI3KαH1047R with high selectivity over PI3KαWT, resulting in the discovery of compound 17. When dosed in the HCC1954 tumor model in mice, 17 provided tumor regressions and a clear pharmacodynamic response. X-ray cocrystal structures from several PI3Kα inhibitors were obtained, revealing three distinct binding modes within PI3KαH1047R including a previously reported cryptic pocket in the C-terminus of the kinase domain wherein we observe a ligand-induced interaction with Arg1047.
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Affiliation(s)
| | | | - Ruth Aranda
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Athenea N. Aloiau
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Briana M. Bobek
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - David M. Briere
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Aaron C. Burns
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | | | - Andrew Calinisan
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Jeffery Clarine
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Adam Elliott
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Lars D. Engstrom
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Robin J. Gunn
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Anthony Ivetac
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Benjamin Jones
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Jon Kuehler
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - J. David Lawson
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Natalie Nguyen
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Cody Parker
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Kelly E. Pearson
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Lisa Rahbaek
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Barbara Saechao
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Xiaolun Wang
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Anna Waters
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Laura Waters
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Ashlee H. Watkins
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Peter Olson
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Christopher R. Smith
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - James G. Christensen
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Matthew A. Marx
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
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Briere D, Sudhakar N, Woods DM, Hallin J, Engstrom LD, Aranda R, Chiang H, Sodré AL, Olson P, Weber JS, Christensen JG. The class I/IV HDAC inhibitor mocetinostat increases tumor antigen presentation, decreases immune suppressive cell types and augments checkpoint inhibitor therapy. Cancer Immunol Immunother 2018; 67:381-392. [PMID: 29124315 PMCID: PMC11028326 DOI: 10.1007/s00262-017-2091-y] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 11/07/2017] [Indexed: 02/07/2023]
Abstract
Checkpoint inhibitor therapy has led to major treatment advances for several cancers including non-small cell lung cancer (NSCLC). Despite this, a significant percentage of patients do not respond or develop resistance. Potential mechanisms of resistance include lack of expression of programmed death ligand 1 (PD-L1), decreased capacity to present tumor antigens, and the presence of an immunosuppressive tumor microenvironment. Mocetinostat is a spectrum-selective inhibitor of class I/IV histone deacetylases (HDACs), a family of proteins implicated in epigenetic silencing of immune regulatory genes in tumor and immune cells. Mocetinostat upregulated PD-L1 and antigen presentation genes including class I and II human leukocyte antigen (HLA) family members in a panel of NSCLC cell lines in vitro. Mocetinostat target gene promoters were occupied by a class I HDAC and exhibited increased active histone marks after mocetinostat treatment. Mocetinostat synergized with interferon γ (IFN-γ) in regulating class II transactivator (CIITA), a master regulator of class II HLA gene expression. In a syngeneic tumor model, mocetinostat decreased intratumoral T-regulatory cells (Tregs) and potentially myeloid-derived suppressor cell (MDSC) populations and increased intratumoral CD8+ populations. In ex vivo assays, patient-derived, mocetinostat-treated Tregs also showed significant down regulation of FOXP3 and HELIOS. The combination of mocetinostat and a murine PD-L1 antibody antagonist demonstrated increased anti-tumor activity compared to either therapy alone in two syngeneic tumor models. Together, these data provide evidence that mocetinostat modulates immune-related genes in tumor cells as well as immune cell types in the tumor microenvironment and enhances checkpoint inhibitor therapy.
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Affiliation(s)
- David Briere
- Mirati Therapeutics, Inc., 9393 Towne Center Dr, Suite 200, San Diego, CA, 92121, USA
| | - Niranjan Sudhakar
- Mirati Therapeutics, Inc., 9393 Towne Center Dr, Suite 200, San Diego, CA, 92121, USA
| | - David M Woods
- NYU Langone Medical Center, New York, NY, 10016, USA
| | - Jill Hallin
- Mirati Therapeutics, Inc., 9393 Towne Center Dr, Suite 200, San Diego, CA, 92121, USA
| | - Lars D Engstrom
- Mirati Therapeutics, Inc., 9393 Towne Center Dr, Suite 200, San Diego, CA, 92121, USA
| | - Ruth Aranda
- Mirati Therapeutics, Inc., 9393 Towne Center Dr, Suite 200, San Diego, CA, 92121, USA
| | - Harrah Chiang
- Mirati Therapeutics, Inc., 9393 Towne Center Dr, Suite 200, San Diego, CA, 92121, USA
| | | | - Peter Olson
- Mirati Therapeutics, Inc., 9393 Towne Center Dr, Suite 200, San Diego, CA, 92121, USA
| | | | - James G Christensen
- Mirati Therapeutics, Inc., 9393 Towne Center Dr, Suite 200, San Diego, CA, 92121, USA.
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