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Dumble M, Xu L, Dominique R, Liu B, Yang H, McBrayer MK, Thomas D, Fahr B, Li H, Huang KS, Robell K, Mulligan C, Russo B, Puzio-Kuter A, Davis T, Vu B. Abstract LB006: PC14586: The first orally bioavailable small molecule reactivator of Y220C mutant p53 in clinical development. Cancer Res 2021. [DOI: 10.1158/1538-7445.am2021-lb006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Mutations in the TP53 gene are the most frequent somatic alterations in human cancer; approximately 50% of all human cancers possess mutations in TP53. Missense mutations in TP53 which result in a non-functional protein are the most frequently identified, these occur across the gene, however most hotspot mutations are localized within the DNA binding domain of the protein. Y220C is one such hotspot mutation, prevalent in ~1.8% of TP53 mutant tumors. PC14586 was structurally designed to bind tightly to a crevice within the mutant protein (KD~2.5 nM). It is the first orally bioavailable small molecule and selective reactivator of Y220C mutant p53 protein in clinical development. In Y220C mutant human cell lines, PC14586 was shown to stabilize the Y220C mutant in the wild type conformation, resulting in reactivation of p53 transcriptional activity and subsequent expression of its target proteins (e.g. p21, MDM2, Bax, PUMA). The reactivation of p53 function is highly selective to Y220C mutant cells and results in arrest of the cell cycle in vitro (IC50 ~0.230-1.8 μM). PC14586 has favorable pharmaceutical properties in pre-clinical species. In nude mice bearing Y220C mutant NUGC3 gastric cancer xenograft tumors, oral administration of PC14586 results in a dose responsive anti-tumor effect, with a target efficacious dose of 100 mg/kg daily resulting in approximately 80% tumor regression after 3 weeks. This anti-tumor effect was driven by a dose responsive pharmacodynamic modulation of the mutant p53 target. In human xenografts, PC14586 was shown to convert Y220C mutant to the wildtype conformation, resulting in activation of p53 transcription. This was demonstrated by the measurement of a p53 mRNA transcriptional signature and at the protein level by increases in p21 and MDM2 in the tumor and Macrophage Inhibitory Cytokine-1 (MIC-1) in both the tumor and plasma. In a C57Bl/6J syngeneic xenograft model bearing the Y220C mutation, administration of PC14586 at 100 mg/kg orally resulted in complete tumor cure in 80% of mice. PC14586 is well tolerated by pre-clinical species and possesses a favorable development profile. The safety and efficacy of PC14586 is currently being evaluated in a seamless Phase I/II clinical study that is a biomarker driven, solid tumor agnostic trial with patients whose tumor bears the Y220C TP53 mutation (NCT study identifier NCT04585750).
Citation Format: Melissa Dumble, Lizhong Xu, Romyr Dominique, Binbin Liu, Hong Yang, Mary-Kate McBrayer, Dafydd Thomas, Bruce Fahr, Hongju Li, Kuo-Sen Huang, Kimberly Robell, Chris Mulligan, Brandon Russo, Anna Puzio-Kuter, Thomas Davis, Binh Vu. PC14586: The first orally bioavailable small molecule reactivator of Y220C mutant p53 in clinical development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB006.
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Affiliation(s)
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- PMV Pharmaceuticals, Cranbury, NJ
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Egbertson M, McGaughey GB, Pitzenberger SM, Stauffer SR, Coburn CA, Stachel SJ, Yang W, Barrow JC, Neilson LA, McWherter M, Perlow D, Fahr B, Munshi S, Allison TJ, Holloway K, Selnick HG, Yang Z, Swestock J, Simon AJ, Sankaranarayanan S, Colussi D, Tugusheva K, Lai MT, Pietrak B, Haugabook S, Jin L, Chen IW, Holahan M, Stranieri-Michener M, Cook JJ, Vacca J, Graham SL. Methyl-substitution of an iminohydantoin spiropiperidine β-secretase (BACE-1) inhibitor has a profound effect on its potency. Bioorg Med Chem Lett 2015. [PMID: 26195137 DOI: 10.1016/j.bmcl.2015.06.082] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [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: 10/23/2022]
Abstract
The IC50 of a beta-secretase (BACE-1) lead compound was improved ∼200-fold from 11 μM to 55 nM through the addition of a single methyl group. Computational chemistry, small molecule NMR, and protein crystallography capabilities were used to compare the solution conformation of the ligand under varying pH conditions to its conformation when bound in the active site. Chemical modification then explored available binding pockets adjacent to the ligand. A strategically placed methyl group not only maintained the required pKa of the piperidine nitrogen and filled a small hydrophobic pocket, but more importantly, stabilized the conformation best suited for optimized binding to the receptor.
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Affiliation(s)
- Melissa Egbertson
- Medicinal Chemistry Department, WP14-2 Merck and Co., West Point, PA 19486, USA.
| | | | - Steven M Pitzenberger
- NMR Structure Elucidation, Process and Analytical Chemistry, WP14-1 Merck and Co., West Point, PA 19486, USA
| | - Shaun R Stauffer
- Medicinal Chemistry Department, WP14-2 Merck and Co., West Point, PA 19486, USA
| | - Craig A Coburn
- Medicinal Chemistry Department, WP14-2 Merck and Co., West Point, PA 19486, USA
| | - Shawn J Stachel
- Medicinal Chemistry Department, WP14-2 Merck and Co., West Point, PA 19486, USA
| | - Wenjin Yang
- Sunesis Pharmaceuticals, 395 Oyster Point Blvd. Ste. 400, South San Francisco, CA 94080, USA
| | - James C Barrow
- Medicinal Chemistry Department, WP14-2 Merck and Co., West Point, PA 19486, USA
| | - Lou Anne Neilson
- Medicinal Chemistry Department, WP14-2 Merck and Co., West Point, PA 19486, USA
| | - Melody McWherter
- Medicinal Chemistry Department, WP14-2 Merck and Co., West Point, PA 19486, USA
| | - Debra Perlow
- Medicinal Chemistry Department, WP14-2 Merck and Co., West Point, PA 19486, USA
| | - Bruce Fahr
- Sunesis Pharmaceuticals, 395 Oyster Point Blvd. Ste. 400, South San Francisco, CA 94080, USA
| | - Sanjeev Munshi
- Structural Biology, WP 14-2 Merck and Co., West Point, PA 19486, USA
| | - Timothy J Allison
- Structural Biology, WP 14-2 Merck and Co., West Point, PA 19486, USA.
| | | | - Harold G Selnick
- Medicinal Chemistry Department, WP14-2 Merck and Co., West Point, PA 19486, USA.
| | - ZhiQiang Yang
- Medicinal Chemistry Department, WP14-2 Merck and Co., West Point, PA 19486, USA
| | - John Swestock
- Process Chemistry, WP 14-1 Merck and Co., West Point, PA 19486, USA
| | - Adam J Simon
- Pharmacology, WP 26-1 Merck and Co., West Point, PA 19486, USA
| | | | - Dennis Colussi
- Pharmacology, WP 26-1 Merck and Co., West Point, PA 19486, USA
| | | | - Ming-Tain Lai
- Pharmacology, WP 26-1 Merck and Co., West Point, PA 19486, USA
| | - Beth Pietrak
- Pharmacology, WP 26-1 Merck and Co., West Point, PA 19486, USA
| | - Shari Haugabook
- Pharmacology, WP 26-1 Merck and Co., West Point, PA 19486, USA
| | - Lixia Jin
- Drug Metabolism, WP 75-B Merck and Co., West Point, PA 19486, USA
| | - I-W Chen
- Drug Metabolism, WP 75-B Merck and Co., West Point, PA 19486, USA
| | - Marie Holahan
- Imaging Research, WP 44c Merck and Co., West Point, PA 19486, USA
| | | | | | - Joseph Vacca
- Medicinal Chemistry Department, WP14-2 Merck and Co., West Point, PA 19486, USA
| | - Samuel L Graham
- Medicinal Chemistry Department, WP14-2 Merck and Co., West Point, PA 19486, USA
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Choong IC, Lew W, Lee D, Pham P, Burdett MT, Lam JW, Wiesmann C, Luong TN, Fahr B, DeLano WL, McDowell RS, Allen DA, Erlanson DA, Gordon EM, O'Brien T. Identification of potent and selective small-molecule inhibitors of caspase-3 through the use of extended tethering and structure-based drug design. J Med Chem 2002; 45:5005-22. [PMID: 12408711 DOI: 10.1021/jm020230j] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The design, synthesis, and in vitro activities of a series of potent and selective small-molecule inhibitors of caspase-3 are described. From extended tethering, a salicylic acid fragment was identified as having binding affinity for the S(4) pocket of caspase-3. X-ray crystallography and molecular modeling of the initial tethering hit resulted in the synthesis of 4, which reversibly inhibited caspase-3 with a K(i) = 40 nM. Further optimization led to the identification of a series of potent and selective inhibitors with K(i) values in the 20-50 nM range. One of the most potent compounds in this series, 66b, inhibited caspase-3 with a K(i) = 20 nM and selectivity of 8-500-fold for caspase-3 vs a panel of seven caspases (1, 2, and 4-8). A high-resolution X-ray cocrystal structure of 4 and 66b supports the predicted binding modes of our compounds with caspase-3.
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Affiliation(s)
- Ingrid C Choong
- Sunesis Pharmaceuticals, Inc., 341 Oyster Point Boulevard, South San Francisco, California 94080, USA.
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