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Petri BJ, Piell KM, Wilt AE, Howser AD, Winkler L, Whitworth MR, Valdes BL, Lehman NL, Clem BF, Klinge CM. MicroRNA regulation of the serine synthesis pathway in endocrine-resistant breast cancer cells. Endocr Relat Cancer 2023; 30:e230148. [PMID: 37650685 PMCID: PMC10546957 DOI: 10.1530/erc-23-0148] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 08/25/2023] [Indexed: 09/01/2023]
Abstract
Despite the successful combination of therapies improving survival of estrogen receptor α (ER+) breast cancer patients with metastatic disease, mechanisms for acquired endocrine resistance remain to be fully elucidated. The RNA binding protein HNRNPA2B1 (A2B1), a reader of N(6)-methyladenosine (m6A) in transcribed RNA, is upregulated in endocrine-resistant, ER+ LCC9 and LY2 cells compared to parental MCF-7 endocrine-sensitive luminal A breast cancer cells. The miRNA-seq transcriptome of MCF-7 cells overexpressing A2B1 identified the serine metabolic processes pathway. Increased expression of two key enzymes in the serine synthesis pathway (SSP), phosphoserine aminotransferase 1 (PSAT1) and phosphoglycerate dehydrogenase (PHGDH), correlates with poor outcomes in ER+ breast patients who received tamoxifen (TAM). We reported that PSAT1 and PHGDH were higher in LCC9 and LY2 cells compared to MCF-7 cells and their knockdown enhanced TAM sensitivity in these-resistant cells. Here we demonstrate that stable, modest overexpression of A2B1 in MCF-7 cells increased PSAT1 and PHGDH and endocrine resistance. We identified four miRNAs downregulated in MCF-7-A2B1 cells that directly target the PSAT1 3'UTR (miR-145-5p and miR-424-5p), and the PHGDH 3'UTR (miR-34b-5p and miR-876-5p) in dual luciferase assays. Lower expression of miR-145-5p and miR-424-5p in LCC9 and ZR-75-1-4-OHT cells correlated with increased PSAT1 and lower expression of miR-34b-5p and miR-876-5p in LCC9 and ZR-75-1-4-OHT cells correlated with increased PHGDH. Transient transfection of these miRNAs restored endocrine-therapy sensitivity in LCC9 and ZR-75-1-4-OHT cells. Overall, our data suggest a role for decreased A2B1-regulated miRNAs in endocrine resistance and upregulation of the SSP to promote tumor progression in ER+ breast cancer.
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Affiliation(s)
- Belinda J. Petri
- Department of Biochemistry & Molecular Genetics, University of Louisville School of Medicine; Louisville, KY 40292 USA
| | - Kellianne M. Piell
- Department of Biochemistry & Molecular Genetics, University of Louisville School of Medicine; Louisville, KY 40292 USA
| | - Ali E. Wilt
- Department of Biochemistry & Molecular Genetics, University of Louisville School of Medicine; Louisville, KY 40292 USA
| | - Alexa D. Howser
- Department of Biochemistry & Molecular Genetics, University of Louisville School of Medicine; Louisville, KY 40292 USA
| | - Laura Winkler
- Department of Biochemistry & Molecular Genetics, University of Louisville School of Medicine; Louisville, KY 40292 USA
| | - Mattie R. Whitworth
- Department of Biochemistry & Molecular Genetics, University of Louisville School of Medicine; Louisville, KY 40292 USA
| | - Bailey L. Valdes
- Department of Biochemistry & Molecular Genetics, University of Louisville School of Medicine; Louisville, KY 40292 USA
| | - Norman L. Lehman
- Department of Biochemistry & Molecular Genetics, University of Louisville School of Medicine; Louisville, KY 40292 USA
- Pathology and Laboratory Medicine, University of Louisville, Louisville, KY, 40202, USA
- The Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA
| | - Brian F. Clem
- Department of Biochemistry & Molecular Genetics, University of Louisville School of Medicine; Louisville, KY 40292 USA
- The Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA
| | - Carolyn M. Klinge
- Department of Biochemistry & Molecular Genetics, University of Louisville School of Medicine; Louisville, KY 40292 USA
- The Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA
- University of Louisville Center for Integrative Environmental Health Sciences (CIEHS)
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Petri BJ, Piell KM, South Whitt GC, Wilt AE, Poulton CC, Lehman NL, Clem BF, Nystoriak MA, Wysoczynski M, Klinge CM. HNRNPA2B1 regulates tamoxifen- and fulvestrant-sensitivity and hallmarks of endocrine resistance in breast cancer cells. Cancer Lett 2021; 518:152-168. [PMID: 34273466 PMCID: PMC8358706 DOI: 10.1016/j.canlet.2021.07.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [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: 03/22/2021] [Revised: 07/07/2021] [Accepted: 07/12/2021] [Indexed: 12/31/2022]
Abstract
Despite new combination therapies improving survival of breast cancer patients with estrogen receptor α (ER+) tumors, the molecular mechanisms for endocrine-resistant disease remain unresolved. Previously we demonstrated that expression of the RNA binding protein and N6-methyladenosine (m6A) reader HNRNPA2B1 (A2B1) is higher in LCC9 and LY2 tamoxifen (TAM)-resistant ERα breast cancer cells relative to parental TAM-sensitive MCF-7 cells. Here we report that A2B1 protein expression is higher in breast tumors than paired normal breast tissue. Modest stable overexpression of A2B1 in MCF-7 cells (MCF-7-A2B1 cells) resulted in TAM- and fulvestrant- resistance whereas knockdown of A2B1 in LCC9 and LY2 cells restored TAM and fulvestrant, endocrine-sensitivity. MCF-7-A2B1 cells gained hallmarks of TAM-resistant metastatic behavior: increased migration and invasion, clonogenicity, and soft agar colony size, which were attenuated by A2B1 knockdown in MCF-7-A2B1 and the TAM-resistant LCC9 and LY2 cells. MCF-7-A2B1, LCC9, and LY2 cells have a higher proportion of CD44+/CD24-/low cancer stem cells (CSC) compared to MCF-7 cells. MCF-7-A2B1 cells have increased ERα and reduced miR-222-3p that targets ERα. Like LCC9 cells, MCF-7-A2B1 have activated AKT and MAPK that depend on A2B1 expression and are growth inhibited by inhibitors of these pathways. These data support that targeting A2B1 could provide a complimentary therapeutic approach to reduce acquired endocrine resistance.
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Affiliation(s)
- Belinda J Petri
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Kellianne M Piell
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Gordon C South Whitt
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Ali E Wilt
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Claire C Poulton
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Norman L Lehman
- Department of Pathology and Laboratory Medicine, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Brian F Clem
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Matthew A Nystoriak
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Marcin Wysoczynski
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Carolyn M Klinge
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, 40292, USA.
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