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Zhuang F, Huang S, Liu L. PYCR3 modulates mtDNA copy number to drive proliferation and doxorubicin resistance in triple-negative breast cancer. Int J Biochem Cell Biol 2024; 171:106581. [PMID: 38642827 DOI: 10.1016/j.biocel.2024.106581] [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: 01/08/2024] [Revised: 04/11/2024] [Accepted: 04/15/2024] [Indexed: 04/22/2024]
Abstract
Triple-negative breast cancer (TNBC) poses significant challenges in treatment due to its aggressive nature and limited therapeutic targets. Understanding the underlying molecular mechanisms driving TNBC progression and chemotherapy resistance is imperative for developing effective therapeutic strategies. Thus, in this study, we aimed to elucidate the role of pyrroline-5-carboxylate reductase 3 (PYCR3) in TNBC pathogenesis and therapeutic response. We observed that PYCR3 is significantly upregulated in TNBC specimens compared to normal breast tissues, correlating with a poorer prognosis in TNBC patients. Knockdown of PYCR3 not only suppresses TNBC cell proliferation but also reverses acquired resistance of TNBC cells to doxorubicin, a commonly used chemotherapeutic agent. Mechanistically, we identified the mitochondrial localization of PYCR3 in TNBC cells and demonstrated its impact on TNBC cell proliferation and sensitivity to doxorubicin through the regulation of mtDNA copy number and mitochondrial respiration. Importantly, Selective reduction of mtDNA copy number using the mtDNA replication inhibitor 2', 3'-dideoxycytidine effectively recapitulates the phenotypic effects observed in PYCR3 knockout, resulting in decreased TNBC cell proliferation and the reversal of doxorubicin resistance through apoptosis induction. Thus, our study underscores the clinical relevance of PYCR3 and highlight its potential as a therapeutic target in TNBC management. By elucidating the functional significance of PYCR3 in TNBC, our findings contribute to a deeper understanding of TNBC biology and provide a foundation for developing novel therapeutic strategies aimed at improving patient outcomes.
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Affiliation(s)
- Feifei Zhuang
- Department of Medical Oncology, Yantaishan Hospital, Yantai, Shandong, China
| | - Shaoyan Huang
- Department of Medical Oncology, Yantaishan Hospital, Yantai, Shandong, China
| | - Lei Liu
- Department of Medical Oncology, Yantaishan Hospital, Yantai, Shandong, China.
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Gürbüz BB, Gülbakan B, Özgül RK, Yalnızoğlu D, Yılmaz DY, Göçmen R, Koşukcu C, Kandemir N, Acar NV, Salih B, Dursun A. Exploring metabolic alterations in PYCR2 deficiency: Unveiling pathways and clinical presentations of hypomyelinating leukodystrophy 10. Am J Med Genet A 2024:e63645. [PMID: 38709052 DOI: 10.1002/ajmg.a.63645] [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: 01/16/2024] [Revised: 04/13/2024] [Accepted: 04/18/2024] [Indexed: 05/07/2024]
Abstract
Proline-5-carboxylate reductase 2, encoded by PYCR2 gene, is an enzyme that catalyzes the last step of proline synthesis from pyrroline-5-carboxylate synthetase to proline. PYCR2 gene defect causes hypomyelinating leukodystrophy 10. Up until now, to our knowledge around 38 patients with PYCR2 defect have been reported. Herein, we describe clinical, neuroradiological, biochemical findings, and metabolomic profiling of three new genetically related cases of PYCR2 defects from a large family. Cerebrospinal fluid (CSF) amino acid levels were measured and untargeted metabolomic profiling of plasma and CSF were conducted and evaluated together with the clinical findings in the patients. While plasma and CSF proline levels were found to be totally normal, untargeted metabolomic profiling revealed mild increases of glutamate, alpha-ketoglutarate, and l-glutamate semialdehyde and marked increases of inosine and xanthine. Our findings and all the previous reports suggest that proline auxotrophy is not the central disease mechanism. Untargeted metabolomics point to mild changes in proline pathway and also in purine/pyrimidine pathway.
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Affiliation(s)
| | - Basri Gülbakan
- Division of Metabolism, Hacettepe University Institute of Child Health, Ankara, Turkey
| | - Rıza Köksal Özgül
- Division of Genetics, Hacettepe University Institute of Child Health, Ankara, Turkey
| | - Dilek Yalnızoğlu
- Division of Pediatric Neurology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Didem Yücel Yılmaz
- Division of Genetics, Hacettepe University Institute of Child Health, Ankara, Turkey
| | - Rahşan Göçmen
- Division of Radiology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Can Koşukcu
- Department of Bioinformatics, Hacettepe University Institute of Health, Ankara, Turkey
| | - Nurgün Kandemir
- Division of Pediatric Endocrinology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Neşe Vardar Acar
- Faculty of Medicine, Hacettepe University Institute of Child Health, Ankara, Turkey
| | - Bekir Salih
- Depatment of Chemistry, Hacettepe University Faculty of Science, Ankara, Turkey
| | - Ali Dursun
- Division of Pediatric Metabolism, Hacettepe University Faculty of Medicine, Ankara, Turkey
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Wu G, Qin S, Gu K, Zhou Y. PYCR2, induced by c-Myc, promotes the invasiveness and metastasis of breast cancer by activating AKT signalling pathway. Int J Biochem Cell Biol 2024; 166:106506. [PMID: 38101533 DOI: 10.1016/j.biocel.2023.106506] [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: 08/08/2023] [Revised: 11/17/2023] [Accepted: 12/11/2023] [Indexed: 12/17/2023]
Abstract
BACKGROUND Pyrroline-5-carboxylate reductase 2 (PYCR2) expression is aberrantly upregulated in colon cancer. However, the functions and underlying mechanisms of PYCR2 in breast cancer remain elusive. The primary objective of the present study was to elucidate the function of PYCR2 in breast cancer and investigate whether PYCR2 may be transcriptionally regulated by c-Myc to activate the AKT signaling pathway. METHODS Immunohistochemical analysis was performed to examine the expression of PYCR2 in breast cancer and adjacent non-cancerous tissues. Western blot and RT-qPCR were utilized to detect PYCR2 expression in breast cancer cells. Cellular functionalities were evaluated through Transwell assays in vitro and lung metastasis formation assays in vivo. Moreover, the impact of PYCR2 on the activation of AKT signaling was determined through western blot and immunohistochemistry analysis. The transcriptional regulation of PYCR2 expression by c-Myc was evaluated via both western blot analysis and luciferase gene reporter assay. RESULTS PYCR2 overexpression was noted in breast cancer. Silencing PYCR2 expression attenuated the invasive and metastatic abilities of breast cancer cells. Furthermore, the activation of the AKT signaling pathway is indispensable for the promotion of invasion and metastasis mediated by PYCR2. Lastly, the binding of c-Myc to the promoter sequence of PYCR2 resulted in the upregulation of PYCR2 transcription. CONCLUSION Taken together, these results indicate that PYCR2 is transcriptionally regulated by c-Myc and promotes invasion and metastasis in breast cancer through the activation of the AKT pathway.
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Affiliation(s)
- Gang Wu
- Department of Radiotherapy and Oncology, The Affiliated Hospital of Jiangnan University, Wuxi 214062, China.
| | | | - Ke Gu
- Department of Radiotherapy and Oncology, The Affiliated Hospital of Jiangnan University, Wuxi 214062, China.
| | - Yanjun Zhou
- Department of Radiotherapy and Oncology, The Affiliated Hospital of Jiangnan University, Wuxi 214062, China.
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Li L, Yang M, Pu X, Tang Y, Fei F, Li Z, Hou H, Chen Q, Wang Q, Wu Y, Zhang Y, Ren C, Gong A. ALKBH5-PYCR2 Positive Feedback Loop Promotes Proneural-Mesenchymal Transition Via Proline Synthesis In GBM. J Cancer 2023; 14:1579-1591. [PMID: 37325047 PMCID: PMC10266253 DOI: 10.7150/jca.84213] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 04/19/2023] [Indexed: 06/17/2023] Open
Abstract
AlkB homolog 5, RNA demethylase (ALKBH5) is abnormally highly expressed in glioblastoma multiforme (GBM) and is negatively correlated with overall survival in GBM patients. In this study, we found a new mechanism that ALKBH5 and pyrroline-5-carboxylate reductase 2 (PYCR2) formed a positive feedback loop involved in proline synthesis in GBM. ALKBH5 promoted PYCR2 expression and PYCR2-mediated proline synthesis; while PYCR2 promoted ALKBH5 expression through the AMPK/mTOR pathway in GBM cells. In addition, ALKBH5 and PYCR2 promoted GBM cell proliferation, migration, and invasion, as well as proneural-mesenchymal transition (PMT). Furthermore, proline rescued AMPK/mTOR activation and PMT after silencing PYCR2 expression. Our findings reveal an ALKBH5-PYCR2 axis linked to proline metabolism, which plays an important role in promoting PMT in GBM cells and may be a promising therapeutic pathway for GBM.
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Affiliation(s)
- Li Li
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiang Su Province, China
| | - Mengting Yang
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiang Su Province, China
| | - Xufeng Pu
- Department of Medical Imaging, The Affiliated Hospital of Jiangsu University, Zhenjiang, Jiang Su Province, China
| | - Yu Tang
- Department of Pathology, The Affiliated Hospital of Jiangsu University, Zhenjiang, Jiang Su Province, China
| | - Fei Fei
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiang Su Province, China
| | - Zhangzuo Li
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiang Su Province, China
| | - Hanjin Hou
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiang Su Province, China
| | - Qian Chen
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiang Su Province, China
| | - Qiaowei Wang
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiang Su Province, China
| | - Yuqing Wu
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiang Su Province, China
| | - Ying Zhang
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiang Su Province, China
| | - Caifang Ren
- Department of Pathology, School of Medicine, Jiangsu University, Zhenjiang, Jiang Su Province, China
| | - Aihua Gong
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiang Su Province, China
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