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Qie S, Majumder M, Mackiewicz K, Howley BV, Peterson YK, Howe PH, Palanisamy V, Diehl JA. Fbxo4-mediated degradation of Fxr1 suppresses tumorigenesis in head and neck squamous cell carcinoma. Nat Commun 2017; 8:1534. [PMID: 29142209 PMCID: PMC5688124 DOI: 10.1038/s41467-017-01199-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 08/29/2017] [Indexed: 02/07/2023] Open
Abstract
The Fbxo4 tumour suppressor is a component of an Skp1-Cul1-F-box E3 ligase for which two substrates are known. Here we show purification of SCFFbxo4 complexes results in the identification of fragile X protein family (FMRP, Fxr1 and Fxr2) as binding partners. Biochemical and functional analyses reveal that Fxr1 is a direct substrate of SCFFbxo4. Consistent with a substrate relationship, Fxr1 is overexpressed in Fbxo4 knockout cells, tissues and in human cancer cells, harbouring inactivating Fbxo4 mutations. Critically, in head and neck squamous cell carcinoma, Fxr1 overexpression correlates with reduced Fbxo4 levels in the absence of mutations or loss of mRNA, suggesting the potential for feedback regulation. Direct analysis reveals that Fbxo4 translation is attenuated by Fxr1, indicating the existence of a feedback loop that contributes to Fxr1 overexpression and the loss of Fbxo4. Ultimately, the consequence of Fxr1 overexpression is the bypass of senescence and neoplastic progression.
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MESH Headings
- Amino Acid Sequence
- Animals
- Carcinoma, Squamous Cell/genetics
- Carcinoma, Squamous Cell/metabolism
- Carcinoma, Squamous Cell/pathology
- Cell Line, Tumor
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Cells, Cultured
- F-Box Proteins/chemistry
- F-Box Proteins/genetics
- F-Box Proteins/metabolism
- Gene Expression Regulation, Neoplastic
- HEK293 Cells
- Head and Neck Neoplasms/genetics
- Head and Neck Neoplasms/metabolism
- Head and Neck Neoplasms/pathology
- Humans
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- NIH 3T3 Cells
- Protein Binding
- Protein Domains
- RNA Interference
- RNA-Binding Proteins/chemistry
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- Sequence Homology, Amino Acid
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Affiliation(s)
- Shuo Qie
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Mrinmoyee Majumder
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, 29425, USA
- Department of Oral Health Sciences and Centre for Oral Health Research, College of Dental Medicine, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Katarzyna Mackiewicz
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Breege V Howley
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Yuri K Peterson
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Philip H Howe
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Viswanathan Palanisamy
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, 29425, USA
- Department of Oral Health Sciences and Centre for Oral Health Research, College of Dental Medicine, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - J Alan Diehl
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, 29425, USA.
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Folini M, Venturini L, Cimino-Reale G, Zaffaroni N. Telomeres as targets for anticancer therapies. Expert Opin Ther Targets 2011; 15:579-93. [DOI: 10.1517/14728222.2011.556621] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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