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Rasmussen DM, Semonis MM, Greene JT, Muretta JM, Thompson AR, Toledo Ramos S, Thomas DD, Pomerantz WCK, Freedman TS, Levinson NM. Allosteric coupling asymmetry mediates paradoxical activation of BRAF by type II inhibitors. eLife 2024; 13:RP95481. [PMID: 38742856 PMCID: PMC11093583 DOI: 10.7554/elife.95481] [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] [Indexed: 05/16/2024] Open
Abstract
The type II class of RAF inhibitors currently in clinical trials paradoxically activate BRAF at subsaturating concentrations. Activation is mediated by induction of BRAF dimers, but why activation rather than inhibition occurs remains unclear. Using biophysical methods tracking BRAF dimerization and conformation, we built an allosteric model of inhibitor-induced dimerization that resolves the allosteric contributions of inhibitor binding to the two active sites of the dimer, revealing key differences between type I and type II RAF inhibitors. For type II inhibitors the allosteric coupling between inhibitor binding and BRAF dimerization is distributed asymmetrically across the two dimer binding sites, with binding to the first site dominating the allostery. This asymmetry results in efficient and selective induction of dimers with one inhibited and one catalytically active subunit. Our allosteric models quantitatively account for paradoxical activation data measured for 11 RAF inhibitors. Unlike type II inhibitors, type I inhibitors lack allosteric asymmetry and do not activate BRAF homodimers. Finally, NMR data reveal that BRAF homodimers are dynamically asymmetric with only one of the subunits locked in the active αC-in state. This provides a structural mechanism for how binding of only a single αC-in inhibitor molecule can induce potent BRAF dimerization and activation.
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Affiliation(s)
- Damien M Rasmussen
- Department of Pharmacology, University of MinnesotaMinneapolisUnited States
- Department of Biochemistry, Molecular Biology, and Biophysics, University of MinnesotaMinneapolisUnited States
| | - Manny M Semonis
- Department of Pharmacology, University of MinnesotaMinneapolisUnited States
| | - Joseph T Greene
- Department of Pharmacology, University of MinnesotaMinneapolisUnited States
| | - Joseph M Muretta
- Department of Biochemistry, Molecular Biology, and Biophysics, University of MinnesotaMinneapolisUnited States
| | - Andrew R Thompson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of MinnesotaMinneapolisUnited States
| | | | - David D Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of MinnesotaMinneapolisUnited States
| | | | - Tanya S Freedman
- Department of Pharmacology, University of MinnesotaMinneapolisUnited States
- Center for Immunology, University of MinnesotaMinneapolisUnited States
- Masonic Cancer Center, University of MinnesotaMinneapolisUnited States
| | - Nicholas M Levinson
- Department of Pharmacology, University of MinnesotaMinneapolisUnited States
- Masonic Cancer Center, University of MinnesotaMinneapolisUnited States
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2
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Corrigendum to: A brain-penetrant RAF dimer antagonist for the noncanonical BRAF oncoprotein of pediatric low-grade astrocytomas. Neuro Oncol 2024; 26:985-986. [PMID: 38521609 PMCID: PMC11066891 DOI: 10.1093/neuonc/noae046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2024] Open
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3
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Yin H, Tang Q, Xia H, Bi F. Targeting RAF dimers in RAS mutant tumors: From biology to clinic. Acta Pharm Sin B 2024; 14:1895-1923. [PMID: 38799634 PMCID: PMC11120325 DOI: 10.1016/j.apsb.2024.02.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 01/02/2024] [Accepted: 02/20/2024] [Indexed: 05/29/2024] Open
Abstract
RAS mutations occur in approximately 30% of tumors worldwide and have a poor prognosis due to limited therapies. Covalent targeting of KRAS G12C has achieved significant success in recent years, but there is still a lack of efficient therapeutic approaches for tumors with non-G12C KRAS mutations. A highly promising approach is to target the MAPK pathway downstream of RAS, with a particular focus on RAF kinases. First-generation RAF inhibitors have been authorized to treat BRAF mutant tumors for over a decade. However, their use in RAS-mutated tumors is not recommended due to the paradoxical ERK activation mainly caused by RAF dimerization. To address the issue of RAF dimerization, type II RAF inhibitors have emerged as leading candidates. Recent clinical studies have shown the initial effectiveness of these agents against RAS mutant tumors. Promisingly, type II RAF inhibitors in combination with MEK or ERK inhibitors have demonstrated impressive efficacy in RAS mutant tumors. This review aims to clarify the importance of RAF dimerization in cellular signaling and resistance to treatment in tumors with RAS mutations, as well as recent progress in therapeutic approaches to address the problem of RAF dimerization in RAS mutant tumors.
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Affiliation(s)
- Huanhuan Yin
- Division of Abdominal Cancer, Department of Medical Oncology, Cancer Center and Laboratory of Molecular Targeted Therapy in Oncology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Qiulin Tang
- Division of Abdominal Cancer, Department of Medical Oncology, Cancer Center and Laboratory of Molecular Targeted Therapy in Oncology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Hongwei Xia
- Division of Abdominal Cancer, Department of Medical Oncology, Cancer Center and Laboratory of Molecular Targeted Therapy in Oncology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Feng Bi
- Division of Abdominal Cancer, Department of Medical Oncology, Cancer Center and Laboratory of Molecular Targeted Therapy in Oncology, West China Hospital, Sichuan University, Chengdu 610041, China
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Aya F, Lanuza-Gracia P, González-Pérez A, Bonnal S, Mancini E, López-Bigas N, Arance A, Valcárcel J. Genomic deletions explain the generation of alternative BRAF isoforms conferring resistance to MAPK inhibitors in melanoma. Cell Rep 2024; 43:114048. [PMID: 38614086 DOI: 10.1016/j.celrep.2024.114048] [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: 08/29/2023] [Revised: 02/06/2024] [Accepted: 03/19/2024] [Indexed: 04/15/2024] Open
Abstract
Resistance to MAPK inhibitors (MAPKi), the main cause of relapse in BRAF-mutant melanoma, is associated with the production of alternative BRAF mRNA isoforms (altBRAFs) in up to 30% of patients receiving BRAF inhibitor monotherapy. These altBRAFs have been described as being generated by alternative pre-mRNA splicing, and splicing modulation has been proposed as a therapeutic strategy to overcome resistance. In contrast, we report that altBRAFs are generated through genomic deletions. Using different in vitro models of altBRAF-mediated melanoma resistance, we demonstrate the production of altBRAFs exclusively from the BRAF V600E allele, correlating with corresponding genomic deletions. Genomic deletions are also detected in tumor samples from melanoma and breast cancer patients expressing altBRAFs. Along with the identification of altBRAFs in BRAF wild-type and in MAPKi-naive melanoma samples, our results represent a major shift in our understanding of mechanisms leading to the generation of BRAF transcripts variants associated with resistance in melanoma.
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Affiliation(s)
- Francisco Aya
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; Medical Oncology Department, Hospital Clinic, Barcelona, Spain; Institut de Investigacions Biomedicas August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Pablo Lanuza-Gracia
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Abel González-Pérez
- Institute for Research in Biomedicine (IRB), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Sophie Bonnal
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Estefania Mancini
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Nuria López-Bigas
- Institute for Research in Biomedicine (IRB), The Barcelona Institute of Science and Technology, Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Ana Arance
- Medical Oncology Department, Hospital Clinic, Barcelona, Spain; Institut de Investigacions Biomedicas August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Juan Valcárcel
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
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5
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Clayton J, Romany A, Matenoglou E, Gavathiotis E, Poulikakos PI, Shen J. Mechanism of Dimer Selectivity and Binding Cooperativity of BRAF Inhibitors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.12.571293. [PMID: 38168366 PMCID: PMC10760002 DOI: 10.1101/2023.12.12.571293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Aberrant signaling of BRAFV600E is a major cancer driver. Current FDA-approved RAF inhibitors selectively inhibit the monomeric BRAFV600E and suffer from tumor resistance. Recently, dimer-selective and equipotent RAF inhibitors have been developed; however, the mechanism of dimer selectivity is poorly understood. Here, we report extensive molecular dynamics (MD) simulations of the monomeric and dimeric BRAFV600E in the apo form or in complex with one or two dimer-selective (PHI1) or equipotent (LY3009120) inhibitor(s). The simulations uncovered the unprecedented details of the remarkable allostery in BRAFV600E dimerization and inhibitor binding. Specifically, dimerization retrains and shifts the αC helix inward and increases the flexibility of the DFG motif; dimer compatibility is due to the promotion of the αC-in conformation, which is stabilized by a hydrogen bond formation between the inhibitor and the αC Glu501. A more stable hydrogen bond further restrains and shifts the αC helix inward, which incurs a larger entropic penalty that disfavors monomer binding. This mechanism led us to propose an empirical way based on the co-crystal structure to assess the dimer selectivity of a BRAFV600E inhibitor. Simulations also revealed that the positive cooperativity of PHI1 is due to its ability to preorganize the αC and DFG conformation in the opposite protomer, priming it for binding the second inhibitor. The atomically detailed view of the interplay between BRAF dimerization and inhibitor allostery as well as cooperativity has implications for understanding kinase signaling and contributes to the design of protomer selective RAF inhibitors.
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Affiliation(s)
- Joseph Clayton
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, United States Food and Drug Administration, Silver Spring, MD 20993, United States
| | - Aarion Romany
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
| | - Evangelia Matenoglou
- Department of Biochemistry, Department of Medicine, Department of Oncology, Montefiore Einstein Comprehensive Cancer Center, Albert Einstein College of Medicine, New York, NY 10461, United States
| | - Evripidis Gavathiotis
- Department of Biochemistry, Department of Medicine, Department of Oncology, Montefiore Einstein Comprehensive Cancer Center, Albert Einstein College of Medicine, New York, NY 10461, United States
| | - Poulikos I Poulikakos
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Jana Shen
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
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Planchard D, Sanborn RE, Negrao MV, Vaishnavi A, Smit EF. BRAF V600E-mutant metastatic NSCLC: disease overview and treatment landscape. NPJ Precis Oncol 2024; 8:90. [PMID: 38627602 PMCID: PMC11021522 DOI: 10.1038/s41698-024-00552-7] [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: 10/06/2023] [Accepted: 02/15/2024] [Indexed: 04/19/2024] Open
Abstract
In this review, we cover the current understanding of BRAF mutations and associated clinical characteristics in patients with metastatic NSCLC, approved and emerging treatment options, BRAF sequencing approaches, and unmet needs. The BRAFV600E mutation confers constitutive activity of the MAPK pathway, leading to enhanced growth, proliferation, and survival of tumor cells. Testing for BRAF mutations enables patients to be treated with therapies that directly target BRAFV600E and the MAPK pathway, but BRAF testing lags behind other oncogene testing in metastatic NSCLC. Additional therapies targeting BRAFV600E mutations provide options for patients with metastatic NSCLC. Emerging therapies and combinations under investigation could potentially overcome issues of resistance and target non-V600E mutations. Therefore, because targeted therapies with enhanced efficacy are on the horizon, being able to identify BRAF mutations in metastatic NSCLC may become even more important.
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Affiliation(s)
- David Planchard
- Thoracic Cancer Group, Department of Medical Oncology, Gustave Roussy, Villejuif, France.
| | - Rachel E Sanborn
- Earle A. Chiles Research Institute, Providence Cancer Institute, Portland, OR, USA
| | - Marcelo V Negrao
- Department of Thoracic/Head and Neck Medical Oncology, Division of Cancer Medicine, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Aria Vaishnavi
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Egbert F Smit
- Department of Pulmonary Disease, Leiden University Medical Centre, Leiden, Netherlands
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Yaman I, Bouffet E. How will tovorafenib change our treatment of pediatric low-grade glioma? Expert Opin Emerg Drugs 2024; 29:1-3. [PMID: 38293894 DOI: 10.1080/14728214.2024.2312817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 01/29/2024] [Indexed: 02/01/2024]
Affiliation(s)
- Inci Yaman
- The Hospital for Sick Children, 55 University Avenue, Toronto, Canada
| | - Eric Bouffet
- The Hospital for Sick Children, 55 University Avenue, Toronto, Canada
- Department of Global Pediatric Medicine, St. Jude Children's Research Hospital, Memphis, TN, USA
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Marsiglia WM, Chow A, Khan ZM, He L, Dar AC. Live-cell target engagement of allosteric MEKi on MEK-RAF/KSR-14-3-3 complexes. Nat Chem Biol 2024; 20:373-381. [PMID: 37919548 PMCID: PMC10948974 DOI: 10.1038/s41589-023-01454-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 09/19/2023] [Indexed: 11/04/2023]
Abstract
The RAS-mitogen-activated protein kinase (MAPK) pathway includes KSR, RAF, MEK and the phospho-regulatory sensor 14-3-3. Specific assemblies among these components drive various diseases and likely dictate efficacy for numerous targeted therapies, including allosteric MEK inhibitors (MEKi). However, directly measuring drug interactions on physiological RAS-MAPK complexes in live cells has been inherently challenging to query and therefore remains poorly understood. Here we present a series of NanoBRET-based assays to quantify direct target engagement of MEKi on MEK1 and higher-order MEK1-bound complexes with ARAF, BRAF, CRAF, KSR1 and KSR2 in the presence and absence of 14-3-3 in living cells. We find distinct MEKi preferences among these complexes that can be compiled to generate inhibitor binding profiles. Further, these assays can report on the influence of the pathogenic BRAF-V600E mutant on MEKi binding. Taken together, these approaches can be used as a platform to screen for compounds intended to target specific complexes in the RAS-MAPK cascade.
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Affiliation(s)
- William M Marsiglia
- Department of Oncological Sciences, The Tisch Cancer Institute, Mount Sinai Center for Therapeutic Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Pharmacological Sciences, The Tisch Cancer Institute, Mount Sinai Center for Therapeutic Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Pharmacology and Toxicology, The University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Arthur Chow
- Department of Oncological Sciences, The Tisch Cancer Institute, Mount Sinai Center for Therapeutic Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Pharmacological Sciences, The Tisch Cancer Institute, Mount Sinai Center for Therapeutic Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Program in Chemical Biology, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Zaigham M Khan
- Department of Oncological Sciences, The Tisch Cancer Institute, Mount Sinai Center for Therapeutic Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Pharmacological Sciences, The Tisch Cancer Institute, Mount Sinai Center for Therapeutic Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Liu He
- Department of Oncological Sciences, The Tisch Cancer Institute, Mount Sinai Center for Therapeutic Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Pharmacological Sciences, The Tisch Cancer Institute, Mount Sinai Center for Therapeutic Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Program in Chemical Biology, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Arvin C Dar
- Department of Oncological Sciences, The Tisch Cancer Institute, Mount Sinai Center for Therapeutic Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Pharmacological Sciences, The Tisch Cancer Institute, Mount Sinai Center for Therapeutic Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Program in Chemical Biology, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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Hajjo R, Sabbah DA, Bardaweel SK, Zhong HA. Targeting the EGFR/RAS/RAF signaling pathway in anticancer research: a recent update on inhibitor design and clinical trials (2020-2023). Expert Opin Ther Pat 2024; 34:51-69. [PMID: 38450537 DOI: 10.1080/13543776.2024.2327307] [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: 11/01/2023] [Accepted: 01/25/2024] [Indexed: 03/08/2024]
Abstract
INTRODUCTION Recent years have seen significant strides in drug developmenttargeting the EGFR/RAS/RAF signaling pathway which is critical forcell growth and proliferation. Protein-protein interaction networksamong EGFR, RAS, and RAF proteins offer insights for drug discovery. This review discusses the drug design and development efforts ofinhibitors targeting these proteins over the past 3 years, detailingtheir structures, selectivity, efficacy, and combination therapy.Strategies to combat drug resistance and minimize toxicities areexplored, along with future research directions. AREA COVERED This review encompasses clinical trials and patents on EGFR, KRAS,and BRAF inhibitors from 2020 to 2023, including advancements indesign and synthesis of proteolysis targeting chimeras (PROTACs) forprotein degradation. EXPERT OPINION To tackle drug resistance, designing allosteric fourth-generationEGFR inhibitors is vital. Covalent, allosteric, or combinationaltherapies, along with PROTAC degraders, are key methods to addressresistance and toxicity in KRAS and BRAF inhibitors.
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Affiliation(s)
- Rima Hajjo
- Department of Pharmacy, Faculty of Pharmacy, Al-Zaytoonah University of Jordan, Amman, Jordan
- Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Board Member, National Center for Epidemics and Communicable Disease Control (JCDC), Amman, Jordan
| | - Dima A Sabbah
- Department of Pharmacy, Faculty of Pharmacy, Al-Zaytoonah University of Jordan, Amman, Jordan
| | - Sanaa K Bardaweel
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Jordan, Amman, Jordan
| | - Haizhen A Zhong
- DSC 309, Department of Chemistry, The University of Nebraska at Omaha, Omaha, NE, USA
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Wang P, Laster K, Jia X, Dong Z, Liu K. Targeting CRAF kinase in anti-cancer therapy: progress and opportunities. Mol Cancer 2023; 22:208. [PMID: 38111008 PMCID: PMC10726672 DOI: 10.1186/s12943-023-01903-x] [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: 08/31/2023] [Accepted: 11/16/2023] [Indexed: 12/20/2023] Open
Abstract
The RAS/mitogen-activated protein kinase (MAPK) signaling cascade is commonly dysregulated in human malignancies by processes driven by RAS or RAF oncogenes. Among the members of the RAF kinase family, CRAF plays an important role in the RAS-MAPK signaling pathway, as well as in the progression of cancer. Recent research has provided evidence implicating the role of CRAF in the physiological regulation and the resistance to BRAF inhibitors through MAPK-dependent and MAPK-independent mechanisms. Nevertheless, the effectiveness of solely targeting CRAF kinase activity remains controversial. Moreover, the kinase-independent function of CRAF may be essential for lung cancers with KRAS mutations. It is imperative to develop strategies to enhance efficacy and minimize toxicity in tumors driven by RAS or RAF oncogenes. The review investigates CRAF alterations observed in cancers and unravels the distinct roles of CRAF in cancers propelled by diverse oncogenes. This review also seeks to summarize CRAF-interacting proteins and delineate CRAF's regulation across various cancer hallmarks. Additionally, we discuss recent advances in pan-RAF inhibitors and their combination with other therapeutic approaches to improve treatment outcomes and minimize adverse effects in patients with RAF/RAS-mutant tumors. By providing a comprehensive understanding of the multifaceted role of CRAF in cancers and highlighting the latest developments in RAF inhibitor therapies, we endeavor to identify synergistic targets and elucidate resistance pathways, setting the stage for more robust and safer combination strategies for cancer treatment.
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Affiliation(s)
- Penglei Wang
- Department of Pathophysiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, 450000, China
- Tianjian Laboratory for Advanced Biomedical Sciences, Zhengzhou, 450052, Henan, China
- China-US (Henan) Hormel Cancer Institute, Zhengzhou, 450000, China
| | - Kyle Laster
- China-US (Henan) Hormel Cancer Institute, Zhengzhou, 450000, China
| | - Xuechao Jia
- Department of Pathophysiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, 450000, China
- Tianjian Laboratory for Advanced Biomedical Sciences, Zhengzhou, 450052, Henan, China
- China-US (Henan) Hormel Cancer Institute, Zhengzhou, 450000, China
| | - Zigang Dong
- Department of Pathophysiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, 450000, China.
- Tianjian Laboratory for Advanced Biomedical Sciences, Zhengzhou, 450052, Henan, China.
- China-US (Henan) Hormel Cancer Institute, Zhengzhou, 450000, China.
- Department of Pathophysiology, School of Basic Medical Sciences, China-US (Henan) Hormel Cancer Institute, AMS, College of Medicine, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, 450001, Henan, China.
| | - Kangdong Liu
- Department of Pathophysiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, 450000, China.
- Tianjian Laboratory for Advanced Biomedical Sciences, Zhengzhou, 450052, Henan, China.
- China-US (Henan) Hormel Cancer Institute, Zhengzhou, 450000, China.
- Department of Pathophysiology, School of Basic Medical Sciences, China-US (Henan) Hormel Cancer Institute, AMS, College of Medicine, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, 450001, Henan, China.
- Basic Medicine Sciences Research Center, Academy of Medical Sciences, Zhengzhou University, Zhengzhou, 450052, Henan, China.
- State Key Laboratory of Esophageal Cancer Prevention and Treatment, Zhengzhou University, Zhengzhou, 450000, Henan, China.
- Provincial Cooperative Innovation Center for Cancer Chemoprevention, Zhengzhou University, Zhengzhou, 450000, Henan, China.
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Rohrer L, Spohr C, Beha C, Griffin R, Braun S, Halbach S, Brummer T. Analysis of RAS and drug induced homo- and heterodimerization of RAF and KSR1 proteins in living cells using split Nanoluc luciferase. Cell Commun Signal 2023; 21:136. [PMID: 37316874 DOI: 10.1186/s12964-023-01146-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 04/27/2023] [Indexed: 06/16/2023] Open
Abstract
The dimerization of RAF kinases represents a key event in their activation cycle and in RAS/ERK pathway activation. Genetic, biochemical and structural approaches provided key insights into this process defining RAF signaling output and the clinical efficacy of RAF inhibitors (RAFi). However, methods reporting the dynamics of RAF dimerization in living cells and in real time are still in their infancy. Recently, split luciferase systems have been developed for the detection of protein-protein-interactions (PPIs), incl. proof-of-concept studies demonstrating the heterodimerization of the BRAF and RAF1 isoforms. Due to their small size, the Nanoluc luciferase moieties LgBiT and SmBiT, which reconstitute a light emitting holoenzyme upon fusion partner promoted interaction, appear as well-suited to study RAF dimerization. Here, we provide an extensive analysis of the suitability of the Nanoluc system to study the homo- and heterodimerization of BRAF, RAF1 and the related KSR1 pseudokinase. We show that KRASG12V promotes the homo- and heterodimerization of BRAF, while considerable KSR1 homo- and KSR1/BRAF heterodimerization already occurs in the absence of this active GTPase and requires a salt bridge between the CC-SAM domain of KSR1 and the BRAF-specific region. We demonstrate that loss-of-function mutations impairing key steps of the RAF activation cycle can be used as calibrators to gauge the dynamics of heterodimerization. This approach identified the RAS-binding domains and the C-terminal 14-3-3 binding motifs as particularly critical for the reconstitution of RAF mediated LgBiT/SmBiT reconstitution, while the dimer interface was less important for dimerization but essential for downstream signaling. We show for the first time that BRAFV600E, the most common BRAF oncoprotein whose dimerization status is controversially portrayed in the literature, forms homodimers in living cells more efficiently than its wildtype counterpart. Of note, Nanoluc activity reconstituted by BRAFV600E homodimers is highly sensitive to the paradox-breaking RAFi PLX8394, indicating a dynamic and specific PPI. We report the effects of eleven ERK pathway inhibitors on RAF dimerization, incl. third-generation compounds that are less-defined in terms of their dimer promoting abilities. We identify Naporafenib as a potent and long-lasting dimerizer and show that the split Nanoluc approach discriminates between type I, I1/2 and II RAFi. Video Abstract.
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Affiliation(s)
- Lino Rohrer
- Institute of Molecular Medicine and Cell Research (IMMZ), Zentrum für Biochemie und Molekulare Zellforschung (ZBMZ), Faculty of Medicine, University of Freiburg, Stefan-Meier-Str. 17, Freiburg, 79104, Germany
| | - Corinna Spohr
- Institute of Molecular Medicine and Cell Research (IMMZ), Zentrum für Biochemie und Molekulare Zellforschung (ZBMZ), Faculty of Medicine, University of Freiburg, Stefan-Meier-Str. 17, Freiburg, 79104, Germany
| | - Carina Beha
- Institute of Molecular Medicine and Cell Research (IMMZ), Zentrum für Biochemie und Molekulare Zellforschung (ZBMZ), Faculty of Medicine, University of Freiburg, Stefan-Meier-Str. 17, Freiburg, 79104, Germany
| | - Ricarda Griffin
- Institute of Molecular Medicine and Cell Research (IMMZ), Zentrum für Biochemie und Molekulare Zellforschung (ZBMZ), Faculty of Medicine, University of Freiburg, Stefan-Meier-Str. 17, Freiburg, 79104, Germany
| | - Sandra Braun
- Institute of Molecular Medicine and Cell Research (IMMZ), Zentrum für Biochemie und Molekulare Zellforschung (ZBMZ), Faculty of Medicine, University of Freiburg, Stefan-Meier-Str. 17, Freiburg, 79104, Germany
| | - Sebastian Halbach
- Institute of Molecular Medicine and Cell Research (IMMZ), Zentrum für Biochemie und Molekulare Zellforschung (ZBMZ), Faculty of Medicine, University of Freiburg, Stefan-Meier-Str. 17, Freiburg, 79104, Germany
- German Cancer Consortium (DKTK), Partner Site Freiburg and German Cancer Research Center (DKFZ), Heidelberg, 69120, Germany
| | - Tilman Brummer
- Institute of Molecular Medicine and Cell Research (IMMZ), Zentrum für Biochemie und Molekulare Zellforschung (ZBMZ), Faculty of Medicine, University of Freiburg, Stefan-Meier-Str. 17, Freiburg, 79104, Germany.
- German Cancer Consortium (DKTK), Partner Site Freiburg and German Cancer Research Center (DKFZ), Heidelberg, 69120, Germany.
- Comprehensive Cancer Center Freiburg (CCCF), Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, 79106, Germany.
- Center for Biological Signalling Studies BIOSS, University of Freiburg, Freiburg, 79104, Germany.
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