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Shinzawa K, Matsumoto S, Sada R, Harada A, Saitoh K, Kato K, Ikeda S, Hirayama A, Yokoi K, Tanemura A, Nimura K, Ikawa M, Soga T, Kikuchi A. GREB1 isoform 4 is specifically transcribed by MITF and required for melanoma proliferation. Oncogene 2023; 42:3142-3156. [PMID: 37658191 PMCID: PMC10575781 DOI: 10.1038/s41388-023-02803-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 02/15/2023] [Revised: 07/24/2023] [Accepted: 08/01/2023] [Indexed: 09/03/2023]
Abstract
Growth regulation by estrogen in breast cancer 1 (GREB1) is involved in hormone-dependent and -independent tumor development (e.g., hepatoblastoma). In this study, we found that a GREB1 splicing variant, isoform 4 (Is4), which encodes C-terminal half of full-length GREB1, is specifically expressed via microphthalmia-associated transcription factor (MITF) in melanocytic melanoma, and that two MITF-binding E-box CANNTG motifs at the 5'-upstream region of GREB1 exon 19 are necessary for GREB1 Is4 transcription. MITF and GREB1 Is4 were strongly co-expressed in approximately 20% of the melanoma specimens evaluated (17/89 cases) and their expression was associated with tumor thickness. GREB1 Is4 silencing reduced melanoma cell proliferation in association with altered expression of cell proliferation-related genes in vitro. In addition, GREB1 Is4 targeting by antisense oligonucleotide (ASO) decreased melanoma xenograft tumor formation and GREB1 Is4 expression in a BRAFV600E; PTENflox melanoma mouse model promoted melanoma formation, demonstrating the crucial role of GREB1 Is4 for melanoma proliferation in vivo. GREB1 Is4 bound to CAD, the rate-limiting enzyme of pyrimidine metabolism, and metabolic flux analysis revealed that GREBI Is4 is necessary for pyrimidine synthesis. These results suggest that MITF-dependent GREB1 Is4 expression leads to melanoma proliferation and GREB1 Is4 represents a new molecular target in melanoma.
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Affiliation(s)
- Koei Shinzawa
- Department of Molecular Biology and Biochemistry, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.
| | - Shinji Matsumoto
- Department of Molecular Biology and Biochemistry, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
- Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Osaka, Japan
| | - Ryota Sada
- Department of Molecular Biology and Biochemistry, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
- Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Osaka, Japan
| | - Akikazu Harada
- Department of Molecular Biology and Biochemistry, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
- Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Osaka, Japan
| | - Kaori Saitoh
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
| | - Keiko Kato
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
| | - Satsuki Ikeda
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
| | - Akiyoshi Hirayama
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
| | - Kazunori Yokoi
- Department of Dermatology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Atsushi Tanemura
- Department of Dermatology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Keisuke Nimura
- Department of Genome Biology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
- Gunma University Initiative for Advanced Research, Gunma University, Maebashi, Gunma, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Tomoyoshi Soga
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
| | - Akira Kikuchi
- Department of Molecular Biology and Biochemistry, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.
- Center for Infectious Disease Education and Research, Osaka University, Suita, Osaka, Japan.
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