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Burley SK, Wu-Wu A, Dutta S, Ganesan S, Zheng SXF. Impact of structural biology and the protein data bank on us fda new drug approvals of low molecular weight antineoplastic agents 2019-2023. Oncogene 2024; 43:2229-2243. [PMID: 38886570 PMCID: PMC11245395 DOI: 10.1038/s41388-024-03077-2] [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: 03/28/2024] [Revised: 06/04/2024] [Accepted: 06/05/2024] [Indexed: 06/20/2024]
Abstract
Open access to three-dimensional atomic-level biostructure information from the Protein Data Bank (PDB) facilitated discovery/development of 100% of the 34 new low molecular weight, protein-targeted, antineoplastic agents approved by the US FDA 2019-2023. Analyses of PDB holdings, the scientific literature, and related documents for each drug-target combination revealed that the impact of structural biologists and public-domain 3D biostructure data was broad and substantial, ranging from understanding target biology (100% of all drug targets), to identifying a given target as likely druggable (100% of all targets), to structure-guided drug discovery (>80% of all new small-molecule drugs, made up of 50% confirmed and >30% probable cases). In addition to aggregate impact assessments, illustrative case studies are presented for six first-in-class small-molecule anti-cancer drugs, including a selective inhibitor of nuclear export targeting Exportin 1 (selinexor, Xpovio), an ATP-competitive CSF-1R receptor tyrosine kinase inhibitor (pexidartinib,Turalia), a non-ATP-competitive inhibitor of the BCR-Abl fusion protein targeting the myristoyl binding pocket within the kinase catalytic domain of Abl (asciminib, Scemblix), a covalently-acting G12C KRAS inhibitor (sotorasib, Lumakras or Lumykras), an EZH2 methyltransferase inhibitor (tazemostat, Tazverik), and an agent targeting the basic-Helix-Loop-Helix transcription factor HIF-2α (belzutifan, Welireg).
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Affiliation(s)
- Stephen K Burley
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA.
- Rutgers Cancer Institute of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ, 08903, USA.
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, San Diego Supercomputer Center, University of California, San Diego, La Jolla, CA, 92093, USA.
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA.
| | - Amy Wu-Wu
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Shuchismita Dutta
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
- Rutgers Cancer Institute of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ, 08903, USA
| | - Shridar Ganesan
- Rutgers Cancer Institute of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ, 08903, USA
| | - Steven X F Zheng
- Rutgers Cancer Institute of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ, 08903, USA
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2
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Young K, Hancock G, Fink E, Zigrossi A, Flowers B, Cooper D, Nguyen V, Martinez M, Mon K, Bosland M, Zak D, Runde A, Sharifi M, Kastrati I, Minh D, Kregel S, Fanning S. Targeting Unique Ligand Binding Domain Structural Features Downregulates DKK1 in Y537S ESR1 Mutant Breast Cancer Cells. RESEARCH SQUARE 2024:rs.3.rs-4542467. [PMID: 38978585 PMCID: PMC11230492 DOI: 10.21203/rs.3.rs-4542467/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Resistance to endocrine therapies remains a major clinical hurdle in breast cancer. Mutations to estrogen receptor alpha (ERα) arise after continued therapeutic pressure. Next generation selective estrogen receptor modulators and degraders/downregulators (SERMs and SERDs) show clinical efficacy, but responses are often non-durable. A tyrosine to serine point mutation at position 537 in the ERα ligand binding domain (LBD) is among the most common and most pathogenic alteration in this setting. It enables endocrine therapy resistance by superceding intrinsic structural-energetic gatekeepers of ER hormone-dependence, it enhances metastatic burden by enabling neomorphic ER-dependent transcriptional programs, and it resists SERM and SERD inhibiton by reducing their binding affinities and abilities to antagonize transcriptional coregulator binding. However, a subset of SERMs and SERDs can achieve efficacy by adopting poses that force the mutation to engage in a new interaction that favors the therapeutic receptor antagonist conformation. We previously described a chemically unconventional SERM, T6I-29, that demonstrates significant anti-proliferative activities in Y537S ERα breast cancer cells. Here, we use a comprehensive suite of structural-biochemical, in vitro, and in vivo approaches to better T6I-29's activities in breast cancer cells harboring Y537S ERα. RNA sequencing in cells treated with T6I-29 reveals a neomorphic downregulation of DKK1, a secreted glycoprotein known to play oncogenic roles in other cancers. Importantly, we find that DKK1 is significantly enriched in ER+ breast cancer plasma compared to healthy controls. This study shows how new SERMs and SERDs can identify new therapeutic pathways in endocrine-resistant ER+ breast cancers.
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Affiliation(s)
- K.S. Young
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - G.R. Hancock
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - E. Fink
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - A. Zigrossi
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - B. Flowers
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - D.A. Cooper
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL 60616
| | - V.T. Nguyen
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL 60616
| | - M. Martinez
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - K.S. Mon
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - M. Bosland
- Department of Pathology, University of Illinois Chicago, Chicago, IL 60607
| | - D. Zak
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - A. Runde
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - M.N. Sharifi
- Department of Medicine, University of Wisconsin, Madison, WI 53705
| | - I. Kastrati
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - D.D.L. Minh
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL 60616
| | - S. Kregel
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - S.W. Fanning
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
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3
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Young K, Hancock G, Fink E, Zigrossi A, Flowers B, Cooper D, Nguyen V, Martinez M, Mon K, Bosland M, Zak D, Runde A, Sharifi M, Kastrati I, Minh D, Kregel S, Fanning S. Targeting Unique Ligand Binding Domain Structural Features Downregulates DKK1 in Y537S ESR1 Mutant Breast Cancer Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.28.596307. [PMID: 38854123 PMCID: PMC11160638 DOI: 10.1101/2024.05.28.596307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Resistance to endocrine therapies remains a major clinical hurdle in breast cancer. Mutations to estrogen receptor alpha (ERα) arise after continued therapeutic pressure. Next generation selective estrogen receptor modulators and degraders/downregulators (SERMs and SERDs) show clinical efficacy, but responses are often non-durable. A tyrosine to serine point mutation at position 537 in the ERα ligand binding domain (LBD) is among the most common and most pathogenic alteration in this setting. It enables endocrine therapy resistance by superceding intrinsic structural-energetic gatekeepers of ER hormone-dependence, it enhances metastatic burden by enabling neomorphic ER-dependent transcriptional programs, and it resists SERM and SERD inhibiton by reducing their binding affinities and abilities to antagonize transcriptional coregulator binding. However, a subset of SERMs and SERDs can achieve efficacy by adopting poses that force the mutation to engage in a new interaction that favors the therapeutic receptor antagonist conformation. We previously described a chemically unconventional SERM, T6I-29, that demonstrates significant anti-proliferative activities in Y537S ERα breast cancer cells. Here, we use a comprehensive suite of structural-biochemical, in vitro, and in vivo approaches to better T6I-29's activities in breast cancer cells harboring Y537S ERα. RNA sequencing in cells treated with T6I-29 reveals a neomorphic downregulation of DKK1, a secreted glycoprotein known to play oncogenic roles in other cancers. Importantly, we find that DKK1 is significantly enriched in ER+ breast cancer plasma compared to healthy controls. This study shows how new SERMs and SERDs can identify new therapeutic pathways in endocrine-resistant ER+ breast cancers.
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Affiliation(s)
- K.S. Young
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - G.R. Hancock
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - E. Fink
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - A. Zigrossi
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - B. Flowers
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - D.A. Cooper
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL 60616
| | - V.T. Nguyen
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL 60616
| | - M. Martinez
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - K.S. Mon
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - M. Bosland
- Department of Pathology, University of Illinois Chicago, Chicago, IL 60607
| | - D. Zak
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - A. Runde
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - M.N. Sharifi
- Department of Medicine, University of Wisconsin, Madison, WI 53705
| | - I. Kastrati
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - D.D.L. Minh
- Department of Chemistry, Illinois Institute of Technology, Chicago, IL 60616
| | - S. Kregel
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
| | - S.W. Fanning
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 50153
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Scott JS, Klinowska TCM. Selective estrogen receptor degraders (SERDs) and covalent antagonists (SERCAs): a patent review (July 2021-December 2023). Expert Opin Ther Pat 2024; 34:333-350. [PMID: 38836316 DOI: 10.1080/13543776.2024.2364803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 05/22/2024] [Indexed: 06/06/2024]
Abstract
INTRODUCTION Breast cancer is the most frequently diagnosed cancer worldwide. With around 70% of breast cancers expressing the estrogen receptor (ER), molecules capable of antagonizing and degrading ER (SERDs) or covalently binding to and antagonizing ER (SERCAs) are at the forefront of efforts to bring better treatments to patients. AREAS COVERED This review summarizes patent applications that claim estrogen receptor degraders (SERDs) and covalent antagonists (SERCAs) identified using SciFinder between the period July 2021 to December 2023. A total of 91 new patent applications from 32 different applicants are evaluated with stratification into acidic SERDs, basic SERDs, SERCAs and miscellaneous degraders. EXPERT OPINION The widespread adoption of fulvestrant in the treatment of ER+ breast cancer continues to stimulate research into orally bioavailable SERDs and SERCAs. A number of molecules have entered clinical development and, although some have been discontinued, a cohort of potential new treatments have generated encouraging efficacy and safety data. Notably, the first example of an oral SERD, elacestrant, has now been approved by the FDA and EMA, providing further encouragement for this class of targeted therapies.
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Affiliation(s)
- James S Scott
- AstraZeneca, Cambridge Biomedical Campus, Cambridge, UK
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Hancock GR, Gertz J, Jeselsohn R, Fanning SW. Estrogen Receptor Alpha Mutations, Truncations, Heterodimers, and Therapies. Endocrinology 2024; 165:bqae051. [PMID: 38643482 PMCID: PMC11075793 DOI: 10.1210/endocr/bqae051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 04/02/2024] [Accepted: 04/17/2024] [Indexed: 04/23/2024]
Abstract
Annual breast cancer (BCa) deaths have declined since its apex in 1989 concomitant with widespread adoption of hormone therapies that target estrogen receptor alpha (ERα), the prominent nuclear receptor expressed in ∼80% of BCa. However, up to ∼50% of patients who are ER+ with high-risk disease experience post endocrine therapy relapse and metastasis to distant organs. The vast majority of BCa mortality occurs in this setting, highlighting the inadequacy of current therapies. Genomic abnormalities to ESR1, the gene encoding ERα, emerge under prolonged selective pressure to enable endocrine therapy resistance. These genetic lesions include focal gene amplifications, hotspot missense mutations in the ligand binding domain, truncations, fusions, and complex interactions with other nuclear receptors. Tumor cells utilize aberrant ERα activity to proliferate, spread, and evade therapy in BCa as well as other cancers. Cutting edge studies on ERα structural and transcriptional relationships are being harnessed to produce new therapies that have shown benefits in patients with ESR1 hotspot mutations. In this review we discuss the history of ERα, current research unlocking unknown aspects of ERα signaling including the structural basis for receptor antagonism, and future directions of ESR1 investigation. In addition, we discuss the development of endocrine therapies from their inception to present day and survey new avenues of drug development to improve pharmaceutical profiles, targeting, and efficacy.
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Affiliation(s)
- Govinda R Hancock
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 60513, USA
| | - Jason Gertz
- Department of Oncological Sciences, Huntsman Cancer Center, University of Utah, Salt Lake City, UT 84112, USA
| | - Rinath Jeselsohn
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Sean W Fanning
- Department of Cancer Biology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 60513, USA
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Ghazanfari N, Doorduin J, van der Weijden CWJ, Willemsen ATM, Glaudemans AWJM, van Waarde A, Dierckx RAJO, de Vries EFJ. Pharmacokinetic Analysis of [ 18F]FES PET in the Human Brain and Pituitary Gland. Mol Imaging Biol 2024; 26:351-359. [PMID: 38263484 DOI: 10.1007/s11307-023-01880-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 01/25/2024]
Abstract
PURPOSE Estrogen receptors (ER) are implicated in psychiatric disorders. We assessed if ER availability in the human brain could be quantified using 16α-[18F]-fluoro-17β-estradiol ([18F]FES) positron emission tomography (PET). PROCEDURES Seven post‑menopausal women underwent a dynamic [18F]FES PET scan with arterial blood sampling. A T1-weighted MRI was acquired for anatomical information. After one week, four subjects received a selective ER degrader (SERD), four hours before the PET scan. Pharmacokinetic analysis was performed using a metabolite-corrected plasma curve as the input function. The optimal kinetic model was selected based on the Akaike information criterion and standard error of estimated parameters. Accuracy of Logan graphical analysis and standardized uptake value (SUV) was determined via correlational analyses. RESULTS The reversible two-tissue compartment model (2T4k) model with fixed K1/k2 was preferred. The total volume of distribution (VT) could be more reliably estimated than the binding potential (BPND). A high correlation of VT with Logan graphical analysis was observed, but only a moderate correlation with SUV. SERD administration resulted in a reduced VT in the pituitary gland, but not in other regions. CONCLUSIONS The optimal quantification method for [18F]FES was the 2T4k with fixed K1/k2 or Logan graphical analysis, but specific binding was only observed in the pituitary gland.
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Affiliation(s)
- Nafiseh Ghazanfari
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands
| | - Janine Doorduin
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands.
| | - Chris W J van der Weijden
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands
| | - Antoon T M Willemsen
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands
| | - Andor W J M Glaudemans
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands
| | - Erik F J de Vries
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands
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Dai R, Bao X, Zhang Y, Huang Y, Zhu H, Yang K, Wang B, Wen H, Li W, Liu J. Hot-Spot Residue-Based Virtual Screening of Novel Selective Estrogen-Receptor Degraders for Breast Cancer Treatment. J Chem Inf Model 2023; 63:7588-7602. [PMID: 37994801 DOI: 10.1021/acs.jcim.3c01503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2023]
Abstract
The estrogen-receptor alfa (ERα) is considered pivotal for breast cancer treatment. Although selective estrogen-receptor degraders (SERDs) have been developed to induce ERα degradation and antagonism, their agonistic effect on the uterine tissue and poor pharmacokinetic properties limit further application of ERα; thus, discovering novel SERDs is necessary. The ligand preferentially interacts with several key residues of the protein (defined as hot-spot residues). Improving the interaction with hot-spot residues of ERα offers a promising avenue for obtaining novel SERDs. In this study, pharmacophore modeling, molecular mechanics/generalized Born surface area (MM/GBSA), and amino-acid mutation were combined to determine several hot-spot residues. Focusing on the interaction with these hot-spot residues, hit fragments A1-A3 and A9 were virtually screened from two fragment libraries. Finally, these hit fragments were linked to generate compounds B1-B3, and their biological activities were evaluated. Remarkably, compound B1 exhibited potent antitumor activity against MCF-7 cells (IC50 = 4.21 nM), favorable ERα binding affinity (Ki = 14.6 nM), and excellent ERα degradative ability (DC50 = 9.7 nM), which indicated its potential to evolve as a promising SERD for breast cancer treatment.
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Affiliation(s)
- Rupeng Dai
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Xueting Bao
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Ying Zhang
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Yan Huang
- School of Artificial Intelligence and Information Technology, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Haohao Zhu
- The Affiliated Mental Health Center of Jiangnan University, Wuxi Central Rehabilitation Hospital, Wuxi, Jiangsu 214151, China
| | - Kundi Yang
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Bo Wang
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Hongmei Wen
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Wei Li
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Jian Liu
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
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Phoenix JT, Budreika A, Kostlan RJ, Hwang JH, Fanning SW, Kregel S. Editorial: Hormone resistance in cancer. Front Endocrinol (Lausanne) 2023; 14:1272932. [PMID: 37693345 PMCID: PMC10484586 DOI: 10.3389/fendo.2023.1272932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 08/17/2023] [Indexed: 09/12/2023] Open
Affiliation(s)
- John T. Phoenix
- Department of Cancer Biology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, United States
- Integrated Program in Biomedical Science, Biochemistry, Molecular and Cancer Biology, Loyola University Chicago, Maywood, IL, United States
| | - Audris Budreika
- Department of Cancer Biology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, United States
| | - Raymond J. Kostlan
- Department of Cancer Biology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, United States
- Integrated Program in Biomedical Science, Biochemistry, Molecular and Cancer Biology, Loyola University Chicago, Maywood, IL, United States
| | - Justin H. Hwang
- Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Sean W. Fanning
- Department of Cancer Biology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, United States
| | - Steven Kregel
- Department of Cancer Biology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, United States
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Unconventional isoquinoline-based SERMs elicit fulvestrant-like transcriptional programs in ER+ breast cancer cells. NPJ Breast Cancer 2022; 8:130. [PMCID: PMC9748900 DOI: 10.1038/s41523-022-00497-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 11/17/2022] [Indexed: 12/15/2022] Open
Abstract
AbstractEstrogen receptor alpha (ERα) is a ligand-dependent master transcriptional regulator and key driver of breast cancer pathology. Small molecule hormones and competitive antagonists favor unique ERα conformational ensembles that elicit ligand-specific transcriptional programs in breast cancer and other hormone-responsive tissues. By affecting disparate ligand binding domain structural features, unconventional ligand scaffolds can redirect ERα genomic binding patterns to engage novel therapeutic transcriptional programs. To improve our understanding of these ERα structure-transcriptional relationships, we develop a series of chemically unconventional antagonists based on the antiestrogens elacestrant and lasofoxifene. High-resolution x-ray co-crystal structures show that these molecules affect both classical and unique structural motifs within the ERα ligand binding pocket. They show moderately reduced antagonistic potencies on ERα genomic activities but are effective anti-proliferative agents in luminal breast cancer cells. Interestingly, they favor a 4-hydroxytamoxifen-like accumulation of ERα in breast cancer cells but lack uterotrophic activities in an endometrial cell line. Importantly, RNA sequencing shows that the lead molecules engage transcriptional pathways similar to the selective estrogen receptor degrader fulvestrant. This advance shows that fulvestrant-like genomic activities can be achieved without affecting ERα accumulation in breast cancer cells.
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