1
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Wang H, Wang F, Ouyang W, Jiang X, Wang Y. BCAT1 overexpression regulates proliferation and c‑Myc/GLUT1 signaling in head and neck squamous cell carcinoma. Oncol Rep 2021; 45:52. [PMID: 33760210 PMCID: PMC7962101 DOI: 10.3892/or.2021.8003] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 11/27/2020] [Indexed: 12/26/2022] Open
Abstract
Branched chain amino acid transaminase 1 (BCAT1) overexpression has been reported in various cancers; however, at present, its significance and biological role in head and neck squamous cell carcinoma (HNSCC) remain unknown. BCAT1 protein expression was upregulated in 56/106 (52.8%) cases of HNSCC. BCAT1 overexpression was associated with tumor-node-metastasis stage, tumor stage and nodal metastasis. The Cancer Genome Atlas data suggested that high BCAT1 expression was associated with poor patient survival. Oncomine data suggested that BCAT1 expression was increased in HNSCC. Functionally, BCAT1 overexpression promoted cell proliferation, colony formation, invasion and cisplatin resistance in FaDu cells. BCAT1 overexpression also upregulated the mitochondrial membrane potential, and increased ATP production, glucose consumption and glucose uptake. Western blotting demonstrated that BCAT1 overexpression upregulated c-Myc and glucose transporter 1 (GLUT1) protein levels. Depletion of c-Myc using small interfering RNA abolished the influence of BCAT1 on GLUT1. Chromatin immunoprecipitation assays demonstrated that c-Myc has binding sites in the GLUT1 promoter. Collectively, the present findings suggested that BCAT1 is upregulated in human HNSCC and regulates HNSCC cell proliferation, invasion, cisplatin sensitivity and c-Myc/GLUT1 signaling.
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Affiliation(s)
- Hongming Wang
- Department of Otolaryngology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Fei Wang
- Department of Otolaryngology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Wenyu Ouyang
- Department of Otolaryngology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Xuejun Jiang
- Department of Otolaryngology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Yan Wang
- Department of Otolaryngology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
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2
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Liu R, Liu J, Wu P, Yi H, Zhang B, Huang W. Flotillin-2 promotes cell proliferation via activating the c-Myc/BCAT1 axis by suppressing miR-33b-5p in nasopharyngeal carcinoma. Aging (Albany NY) 2021; 13:8078-8094. [PMID: 33744853 PMCID: PMC8034900 DOI: 10.18632/aging.202726] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 02/09/2021] [Indexed: 04/13/2023]
Abstract
Previously, we elucidated the function of flotilin-2 (FLOT2) and branched-chain amino acid transaminase 1(BCAT1) in nasopharyngeal carcinoma (NPC). However, the relationship between FLOT2 and BCAT1 in promoting NPC progression remains unknown. Here, we observed that FLOT2 upregulated BCAT1 expression in NPC cells. Ectopic expression of BCAT1 significantly antagonized the inhibitory effects on NPC cell proliferation induced by FLOT2 depletion. Consequently, BCAT1 knockdown markedly inhibited the pro-proliferative effects of FLOT2 overexpression in NPC cells. FLOT2 expression was positively correlated with BCAT1 expression in NPC tissues and was inversely correlated with the prognosis of NPC patients. Mechanistically, FLOT2 maintains the expression level of c-Myc, a positive transcription factor of BCAT1, and subsequently promote BCAT1 transcription. FLOT2 inhibited miR-33b-5p in NPC cells and attenuated its inhibitory effects on c-Myc. Further, experimental validation of the function of the FLOT2/miR-33b-5p/c-Myc/BCAT1 axis in regulating NPC cell proliferation was performed. Our results revealed that FLOT2 promotes NPC cell proliferation by suppressing miR-33b-5p, to maintain proper levels of c-Myc, and upregulate BCAT1trancription. Therefore, the FLOT2/miR-33b-5p/c-Myc/BCAT1 axis is a potential therapeutic target for NPC.
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Affiliation(s)
- Rong Liu
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- College of Biology and Environmental Sciences, Jishou University, Jishou 416000, China
| | - Jie Liu
- Department of Pathology, Changsha Central Hospital, Changsha 410004, China
| | - Ping Wu
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Hong Yi
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- Research Center of Carcinogenesis and Targeted Therapy, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Bin Zhang
- Department of Histology and Embryology, School of Basic Medicine, Central South University, Changsha 410013, China
| | - Wei Huang
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- Research Center of Carcinogenesis and Targeted Therapy, Xiangya Hospital, Central South University, Changsha 410008, China
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3
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Young GP, Symonds EL, Nielsen HJ, Ferm L, Christensen IJ, Dekker E, van der Vlugt M, Mallant-Hent RC, Boulter N, Yu B, Chan M, Tevz G, LaPointe LC, Pedersen SK. Evaluation of a panel of tumor-specific differentially-methylated DNA regions in IRF4, IKZF1 and BCAT1 for blood-based detection of colorectal cancer. Clin Epigenetics 2021; 13:14. [PMID: 33478584 PMCID: PMC7818774 DOI: 10.1186/s13148-020-00999-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 12/22/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Differentially-methylated regions (DMRs) are characteristic of colorectal cancer (CRC) and some occur more frequently than common mutations. This study aimed to evaluate the clinical utility of assaying circulating cell-free DNA for methylation in BCAT1, IKZF1 and IRF4 for detection of CRC. METHODS A multiplexed real-time PCR assay targeting DMRs in each of the three genes was developed. Assay accuracy was explored in plasma specimens banked from observational cross-sectional trials or from volunteers scheduled for colonoscopy or prior to CRC surgery. RESULTS 1620 specimens were suitable for study inclusion including 184 and 616 cases with CRC and adenomas, respectively, and 820 cases without neoplasia (overall median age, 63.0 years; 56% males). Combining the PCR signals for all targeted DMRs returned the best sensitivity for CRC (136/184, 73.9%, 95% CI 67.1-79.7), advanced adenomas (53/337, 15.7%, 95% CI 12.0-20.1) and high-grade dysplastic (HGD) adenomas (9/35, 25.7%, 95% CI 14.0-42.3) with a 90.1%, specificity for neoplasia (739/820, 95% CI 87.9-92.0, p < 0.01). Detection of methylation in all three genes were more likely in CRC cases than those without it (OR 28.5, 95% CI 7.3-121.2, p < 0.0001). Of the 81 positive cases without neoplasia, 62 (76.5%) were positive by a single PCR replicate only and predominantly due to detection of methylated BCAT1 (53.2%). Single replicate positivity was significantly higher than that in CRC (26/136, 19.1%, p < 0.0001), and single BCAT1 replicate positivity was more likely in cases without neoplasia than in CRC (OR 17.7, 95% CI 6.6-43.3, p < 0.0001). When a positive result was limited to those with ≥ 1 PCR replicate positive for either IKZF1 or IRF4, or at least two replicates positive for BCAT1, the multi-panel test maintained a high sensitivity for CRC (131/184, 71.2%, 95% CI 64.3-77.3) and HGD adenomas (8/35, 22.9%, 95% CI 11.8-39.3, p = 0.029) but improved specificity significantly (772/820, 94.1%, 95% CI 92.3-95.6, p < 0.0001 vs. any PCR replicate positive). CONCLUSION The multi-panel methylation assay differentiates cases with CRC from those without it and does so with high specificity when criteria for BCAT1 detection are applied. The marker panel is flexible and studies in those at average risk for CRC are now warranted to determine which panel configuration best suits screening goals. TRIAL REGISTRATION ACTRN12611000318987. Registered 25 March 2011, https://www.anzctr.org.au/ ACTRN12611000318987.
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Affiliation(s)
- Graeme P Young
- Flinders Health and Medical Research Institute, Flinders University, Adelaide, Australia
| | - Erin L Symonds
- Flinders Health and Medical Research Institute, Flinders University, Adelaide, Australia
- Bowel Health Service, Flinders Medical Centre, Bedford Park, South Australia, Australia
| | - Hans Jørgen Nielsen
- Department of Surgical Gastroenterology, Hvidovre Hospital, University of Copenhagen, Hvidovre, Denmark
| | - Linnea Ferm
- Department of Surgical Gastroenterology, Hvidovre Hospital, University of Copenhagen, Hvidovre, Denmark
| | - Ib J Christensen
- Department of Surgical Gastroenterology, Hvidovre Hospital, University of Copenhagen, Hvidovre, Denmark
| | - Evelien Dekker
- Department of Gastroenterology and Hepatology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Manon van der Vlugt
- Department of Gastroenterology and Hepatology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | | | - Nicky Boulter
- Clinical Genomics Pty Ltd, North Ryde, NSW, Australia
| | - Betty Yu
- Clinical Genomics Pty Ltd, North Ryde, NSW, Australia
| | - Michelle Chan
- Clinical Genomics Pty Ltd, North Ryde, NSW, Australia
| | - Gregor Tevz
- Clinical Genomics Pty Ltd, North Ryde, NSW, Australia
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4
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Lin X, Tan S, Fu L, Dong Q. BCAT1 Overexpression Promotes Proliferation, Invasion, and Wnt Signaling in Non-Small Cell Lung Cancers. Onco Targets Ther 2020; 13:3583-3594. [PMID: 32425554 PMCID: PMC7196801 DOI: 10.2147/ott.s237306] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/19/2020] [Indexed: 01/10/2023] Open
Abstract
Introduction Dysregulation of BCAT1 has been implicated in carcinogenesis. However, its clinical significance and biological roles in human non-small cell lung cancer (NSCLC) are not clear. Methods Immunohistochemistry was used to examine the protein expression of BCAT1 in 107 cases of lung cancer tissues. Biological roles and potential mechanisms of BCAT1 were examined using MTT, colony formation assay, Matrigel invasion assay, Western blot, RNA-sequencing, and luciferase reporter assay. Results We found BCAT1 was upregulated in 60 of 107 lung cancer tissues and correlated with nodal metastasis, advanced stages and short overall survival. The Cancer Genome Atlas (TCGA) and ONCOMINE data analyses also indicated that BCAT1 was elevated in human NSCLC tissues. BCAT1 protein was higher in lung cancer cell lines than in normal bronchial epithelial cell line. BCAT1 overexpression increased the cell growth rate, colony numbers and invasion abilities in both BEAS-2B and H1299 cell lines, while BCAT1 siRNA decreased the cell proliferation rate, colony numbers, and inhibited invasion. RNA-sequencing (RNA-seq) and Gene Set Enrichment Analysis (GSEA) analyses indicated that BCAT1 overexpression activated Wnt/Myc signaling. Western blot revealed that BCAT1 increased protein expression of MMP7, cyclin D1, c-Myc, and decreased E-cadherin and p27 in the BEAS-2B and H1299 cell lines. Further experiments showed that BCAT1 overexpression elevated Wnt reporter luciferase activity and increased activate β-catenin protein while downregulating p-β-catenin protein expression. BCAT1 knockdown showed the opposite effects. TCGA data analysis suggested positive correlations between BCAT1 and c-Myc, cyclin D1, and MMP7 mRNA. Blockage of Wnt signaling using an inhibitor (ICG-001) downregulated c-Myc, cyclin D1, MMP7 expressions and abolished the upregulating effects of BCAT1 on these proteins. Conclusion In summary, our data showed that BCAT1 was overexpressed in human NSCLCs. BCAT1 facilitated cell proliferation and invasion possibly through regulation of the Wnt signaling pathway.
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Affiliation(s)
- Xiumin Lin
- Department of Pathology, College of Basic Medical Science, China Medical University, Shenyang, People's Republic of China.,Department of Pathology, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Shutao Tan
- Department of Urology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China
| | - Lin Fu
- Department of Pathology, College of Basic Medical Science, China Medical University, Shenyang, People's Republic of China.,Department of Pathology, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Qianze Dong
- Department of Pathology, College of Basic Medical Science, China Medical University, Shenyang, People's Republic of China.,Department of Pathology, The First Affiliated Hospital of China Medical University, Shenyang, China
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5
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Xu Y, Yu W, Yang T, Zhang M, Liang C, Cai X, Shao Q. Overexpression of BCAT1 is a prognostic marker in gastric cancer. Hum Pathol 2018; 75:41-46. [PMID: 29447920 DOI: 10.1016/j.humpath.2018.02.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 02/01/2018] [Accepted: 02/02/2018] [Indexed: 01/08/2023]
Abstract
As one form of branched-chain amino-acid transaminase (BCAT) enzymes, It has been found that up-regulation of BCAT1 is associated with poor prognosis in numerous types of tumors, but studies on the role of BCAT1 expression in gastric cancer (GC) are rare. The aims of this study were to detect BCAT1 expression in GC and to analyze its association with prognosis of GC patients. Microarray experiments were performed on the Affymetrix U133 plus 2.0 GeneChip Array. The protein and messenger RNA levels of BCAT1 were validated by immunohistochemistry and real-time quantitative polymerase chain reaction in GC tissues and adjacent noncancerous tissues. Our study shows that the expression of BCAT1 significantly increased in human GC. Furthermore, it can also be found that BCAT1 overexpression was associated with TNM stage (P < .05), local invasion (P < .05), Lauren type (P < .05), tumor classification (P < .05), lymph node metastasis (P < .05), and presence of distant metastasis (P < .05). Kaplan-Meier survival analysis revealed that high BCAT1 expression predicted significantly worse overall survival (P < .05), whereas multivariate Cox regression analysis showed that BCAT1 affects GC independently. In conclusion, up-regulation of BCAT1 indicated a poor survival rate of GC and may serve as a useful marker for predicting the outcome of patients with GC.
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Affiliation(s)
- Yuan Xu
- Department of Gastrointestinal Surgery, Ningbo City Medical Center Lihuili Hospital, Ningbo, 315000, PR China.
| | - Weiming Yu
- Department of Gastrointestinal Surgery, Ningbo City Medical Center Lihuili Hospital, Ningbo, 315000, PR China
| | - Taotao Yang
- Department of Pharmacy, Ningbo City Medical Center Lihuili Hospital, Ningbo, 315000, PR China
| | - Miaozun Zhang
- Department of Gastrointestinal Surgery, Ningbo City Medical Center Lihuili Hospital, Ningbo, 315000, PR China
| | - Chao Liang
- Department of Gastrointestinal Surgery, Ningbo City Medical Center Lihuili Hospital, Ningbo, 315000, PR China
| | - Xianlei Cai
- Department of Gastrointestinal Surgery, Ningbo City Medical Center Lihuili Hospital, Ningbo, 315000, PR China
| | - Qinshu Shao
- Department of Gastrointestinal Surgery, Zhejiang Provincial People's Hospital, Hangzhou, 310014, PR China
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6
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Wang L, Koutelou E, Hirsch C, McCarthy R, Schibler A, Lin K, Lu Y, Jeter C, Shen J, Barton MC, Dent SYR. GCN5 Regulates FGF Signaling and Activates Selective MYC Target Genes during Early Embryoid Body Differentiation. Stem Cell Reports 2017; 10:287-299. [PMID: 29249668 PMCID: PMC5768892 DOI: 10.1016/j.stemcr.2017.11.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 11/14/2017] [Accepted: 11/14/2017] [Indexed: 12/12/2022] Open
Abstract
Precise control of gene expression during development is orchestrated by transcription factors and co-regulators including chromatin modifiers. How particular chromatin-modifying enzymes affect specific developmental processes is not well defined. Here, we report that GCN5, a histone acetyltransferase essential for embryonic development, is required for proper expression of multiple genes encoding components of the fibroblast growth factor (FGF) signaling pathway in early embryoid bodies (EBs). Gcn5-/- EBs display deficient activation of ERK and p38, mislocalization of cytoskeletal components, and compromised capacity to differentiate toward mesodermal lineage. Genomic analyses identified seven genes as putative direct targets of GCN5 during early differentiation, four of which are cMYC targets. These findings established a link between GCN5 and the FGF signaling pathway and highlighted specific GCN5-MYC partnerships in gene regulation during early differentiation.
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Affiliation(s)
- Li Wang
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Program in Epigenetics and Molecular Carcinogenesis, The Graduate School of Biomedical Sciences (GSBS) of the University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Evangelia Koutelou
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Calley Hirsch
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Ryan McCarthy
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Andria Schibler
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Program in Genes and Development, The Graduate School of Biomedical Sciences (GSBS) of the University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Kevin Lin
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Yue Lu
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Collene Jeter
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Jianjun Shen
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Michelle C Barton
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Program in Epigenetics and Molecular Carcinogenesis, The Graduate School of Biomedical Sciences (GSBS) of the University of Texas Health Science Center at Houston, Houston, TX 77030, USA; Program in Genes and Development, The Graduate School of Biomedical Sciences (GSBS) of the University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Sharon Y R Dent
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Program in Epigenetics and Molecular Carcinogenesis, The Graduate School of Biomedical Sciences (GSBS) of the University of Texas Health Science Center at Houston, Houston, TX 77030, USA; Program in Genes and Development, The Graduate School of Biomedical Sciences (GSBS) of the University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
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7
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Tsangaris GT, Dimas K, Malamou A, Katsafadou A, Papathanasiou C, Stravopodis DJ, Vorgias CE, Gazouli M, Anagnostopoulos AK. Molecular Proteomic Characterization of a Pediatric Medulloblastoma Xenograft. Cancer Genomics Proteomics 2017; 14:267-275. [PMID: 28647700 PMCID: PMC5572304 DOI: 10.21873/cgp.20037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 06/09/2017] [Accepted: 06/12/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND/AIM Medulloblastoma (MBL), an archetypal primitive neuroectodermal tumor of the cerebellum, is the most common pediatric central nervous system malignancy representing approximately 20% of all childhood brain tumors. Herein, we report on a new xenotransplantable tumor cell line, derived from a 6-year-old female patient with cerebellar medulloblastoma, and the completele proteome molecular characterization of subsequent tumors from MBL xenotrasplanted mice. MATERIALS AND METHODS Tumors were grown in nude mice as subcutaneous xenografts (MBLX) composed of small round cells with hyperchromatic nuclei and scant cytoplasm. Tumor specimen were extracted from animals upon their sacrifice and their molecular proteomic content was analyzed by 2-DE coupled to MALDI-TOF MS analysis. RESULTS Altogether 350 single-gene products were identified through the current approach, reported as the MBLX database. CONCLUSION This new xenotransplantable tumor model, offers the scientific community valuable insight on the validity of xenografts altogether, while providing the means for a novel experimental model towards the study of human MBL.
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Affiliation(s)
- George T Tsangaris
- Proteomics Research Unit, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Konstantinos Dimas
- Laboratory of Pharmacology, Faculty of Medicine, University of Thessaly, Larissa, Greece
| | - Angeliki Malamou
- Proteomics Research Unit, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Angeliki Katsafadou
- Proteomics Research Unit, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Chrissa Papathanasiou
- Hematology/Oncology Unit, First Department of Pediatrics, Aghia Sophia Children's Hospital, University of Athens, Athens, Greece
| | - Dimitrios J Stravopodis
- Department of Cell Biology and Biophysics, Faculty of Biology, School of Sciences, National and Kapodistrian University of Athens, Athens, Greece
| | - Constantinos E Vorgias
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Maria Gazouli
- Department of Molecular Biology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
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赖 爱, 谢 斌. BCAT1促进肿瘤发生发展的研究进展. Shijie Huaren Xiaohua Zazhi 2017; 25:1536-1542. [DOI: 10.11569/wcjd.v25.i17.1536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
支链氨基酸转移酶1(branched-chain amino acid transaminase 1, BCAT1)是催化支链氨基酸代谢的关键酶. 国内外研究已证实BCAT1在多种恶性肿瘤中呈现高表达, 并提示与肿瘤细胞增殖、转移及侵袭密切相关. 本文拟就BCAT1的理化性质、生物学功能及其与肿瘤发生、发展的相关研究进行简要综述, 为进一步研究BCAT1与恶性肿瘤的关系提供线索.
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9
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Zhu W, Shao Y, Peng Y. MicroRNA-218 inhibits tumor growth and increases chemosensitivity to CDDP treatment by targeting BCAT1 in prostate cancer. Mol Carcinog 2017; 56:1570-1577. [PMID: 28052414 DOI: 10.1002/mc.22612] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Revised: 11/16/2016] [Accepted: 12/31/2016] [Indexed: 12/16/2022]
Abstract
MicroRNAs have been reported to be associated with chemosensitivity of several types of cancers. However, the underlying molecular mechanisms are poorly understood. In this study, we explored miR-218 increased the chemosensitivity to cis-diaminedichloroplatinum treatment of prostate cancer. We found that the expression level of miR-218 was down-regulated in the human prostate cancer specimens. Moreover, overexpression of miR-218 inhibited cell viability, migration, and invasion in PC3 and DU145 cells. Furthermore, we demonstrated that the tumor suppressive role of miR-218 was mediated by negatively regulating branched-chain amino acid transaminase 1 (BCAT1) protein expression. Importantly, overexpression of BCAT1 decreased the chemosensitivity to CDDP treatment of PC3 and DU145 cells. Our study is the first to identify the positive role of miR-218 in chemosensitivity, which will facilitate the development of novel therapeutic strategies for prostate cancer in the future.
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Affiliation(s)
- Wenjing Zhu
- Department of Urology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yiqun Shao
- Department of Urology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yu Peng
- Department of Urology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
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10
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Wang ZQ, Faddaoui A, Bachvarova M, Plante M, Gregoire J, Renaud MC, Sebastianelli A, Guillemette C, Gobeil S, Macdonald E, Vanderhyden B, Bachvarov D. BCAT1 expression associates with ovarian cancer progression: possible implications in altered disease metabolism. Oncotarget 2016; 6:31522-43. [PMID: 26372729 PMCID: PMC4741622 DOI: 10.18632/oncotarget.5159] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 08/28/2015] [Indexed: 12/17/2022] Open
Abstract
Previously, we have identified the branched chain amino-acid transaminase 1 (BCAT1) gene as notably hypomethylated in low-malignant potential (LMP) and high-grade (HG) serous epithelial ovarian tumors, compared to normal ovarian tissues. Here we show that BCAT1 is strongly overexpressed in both LMP and HG serous epithelial ovarian tumors, which probably correlates with its hypomethylated status. Knockdown of the BCAT1 expression in epithelial ovarian cancer (EOC) cells led to sharp decrease of cell proliferation, migration and invasion and inhibited cell cycle progression. BCAT1 silencing was associated with the suppression of numerous genes and pathways known previously to be implicated in ovarian tumorigenesis, and the induction of some tumor suppressor genes (TSGs). Moreover, BCAT1 suppression resulted in downregulation of numerous genes implicated in lipid production and protein synthesis, suggesting its important role in controlling EOC metabolism. Further metabolomic analyses were indicative for significant depletion of most amino acids and different phospho- and sphingolipids following BCAT1 knockdown. Finally, BCAT1 suppression led to significantly prolonged survival time in xenograft model of advanced peritoneal EOC. Taken together, our findings provide new insights about the functional role of BCAT1 in ovarian carcinogenesis and identify this transaminase as a novel EOC biomarker and putative EOC therapeutic target.
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Affiliation(s)
- Zhi-Qiang Wang
- Department of Molecular Medicine, Laval University, Québec PQ, Canada.,Centre de recherche du CHU de Québec, L'Hôtel-Dieu de Québec, Québec PQ, Canada
| | - Adnen Faddaoui
- Department of Molecular Medicine, Laval University, Québec PQ, Canada.,Centre de recherche du CHU de Québec, L'Hôtel-Dieu de Québec, Québec PQ, Canada
| | | | - Marie Plante
- Centre de recherche du CHU de Québec, L'Hôtel-Dieu de Québec, Québec PQ, Canada.,Department of Obstetrics and Gynecology, Laval University, Québec PQ, Canada
| | - Jean Gregoire
- Centre de recherche du CHU de Québec, L'Hôtel-Dieu de Québec, Québec PQ, Canada.,Department of Obstetrics and Gynecology, Laval University, Québec PQ, Canada
| | - Marie-Claude Renaud
- Centre de recherche du CHU de Québec, L'Hôtel-Dieu de Québec, Québec PQ, Canada.,Department of Obstetrics and Gynecology, Laval University, Québec PQ, Canada
| | - Alexandra Sebastianelli
- Centre de recherche du CHU de Québec, L'Hôtel-Dieu de Québec, Québec PQ, Canada.,Department of Obstetrics and Gynecology, Laval University, Québec PQ, Canada
| | - Chantal Guillemette
- Centre de recherche du CHU de Québec, CHUL, Québec PQ, Canada.,Faculty of Pharmacy, Laval University, Québec PQ, Canada
| | - Stéphane Gobeil
- Department of Molecular Medicine, Laval University, Québec PQ, Canada.,Centre de recherche du CHU de Québec, CHUL, Québec PQ, Canada
| | - Elizabeth Macdonald
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Barbara Vanderhyden
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Dimcho Bachvarov
- Department of Molecular Medicine, Laval University, Québec PQ, Canada.,Centre de recherche du CHU de Québec, L'Hôtel-Dieu de Québec, Québec PQ, Canada
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11
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Xu M, Liu Q, Jia Y, Tu K, Yao Y, Liu Q, Guo C. BCAT1 promotes tumor cell migration and invasion in hepatocellular carcinoma. Oncol Lett 2016; 12:2648-2656. [PMID: 27698837 PMCID: PMC5038498 DOI: 10.3892/ol.2016.4969] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Accepted: 07/26/2016] [Indexed: 12/29/2022] Open
Abstract
Branched-chain amino acid transaminase 1 (BCAT1) has been associated with numerous types of tumors; however, few previous studies have evaluated the expression and role of BCAT1 in hepatocellular carcinoma (HCC). In the present study, the expression of BCAT1 was detected by reverse transcription-quantitative polymerase chain reaction and immunoblotting in six HCC cell lines and 74 pairs of HCC and adjacent non-cancerous liver tissues. In addition, the correlation between the expression levels of c-Myc and BCAT1 was analyzed using immunohistochemistry. Furthermore, RNA silencing was performed using c-Myc-specific or BCAT1-specific small interfering RNA, after which wound healing and Transwell cell invasion assays were performed. Finally, the clinicopathological characteristics of BCAT1 in patients with HCC were analyzed. It was shown that the expression of BCAT1 was significantly higher in HCC tissues compared with adjacent non-tumor tissues (P<0.001), and in HCC cell lines compared within the L-02 hepatic cell line (P<0.001). In addition, immunohistochemical analyses indicated that the expression of BCAT1 was positively correlated with c-Myc (r=0.706, P<0.001). BCAT1 expression was shown to be downregulated in c-Myc-knockdown cells, and silencing of BCAT1 expression reduced the invasion and migration of HCC cells. Furthermore, a clinical analysis indicated that BCAT1 expression in HCC tissues was significantly associated with the tumor-node-metastasis stage, tumor number and tumor differentiation (all P<0.05), and that BCAT1 was able to predict the 5-year survival and disease-free survival rates of patients with HCC (both P<0.001). The results of the present study suggested that BCAT1 expression is upregulated in patients with HCC, and that BCAT1 may serve as a potential molecular target for the diagnosis and treatment of HCC.
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Affiliation(s)
- Meng Xu
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Qingquan Liu
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Yuli Jia
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Kangsheng Tu
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Yingmin Yao
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Qingguang Liu
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Cheng Guo
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
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12
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Over-expression of BCAT1, a c-Myc target gene, induces cell proliferation, migration and invasion in nasopharyngeal carcinoma. Mol Cancer 2013; 12:53. [PMID: 23758864 PMCID: PMC3698204 DOI: 10.1186/1476-4598-12-53] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 05/31/2013] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Nasopharyngeal carcinoma (NPC) is a common malignant tumor in southern China and Southeast Asia, but its molecular mechanisms of pathogenesis are poorly understood. Our previous work has demonstrated that BCAT1 mRNA is over expressed in NPC and knocking down its expression in 5-8F NPC cell line can potently inhibit cell cycle progression and cell proliferation. However, the mechanism of BCAT1 up-regulation and its functional role in NPC development remain to be elucidated yet. METHODS Immunohistochemistry (IHC) method was utilized to detect the expression of BCAT1 protein in NPC at different pathological stages. The roles of gene mutation, DNA amplification and transcription factor c-Myc in regulating BCAT1 expression were analyzed using PCR-sequencing, quantitative polymerase chain reaction (qPCR), IHC, ChIP and luciferase reporter system, respectively. The functions of BCAT1 in colony formation, cell migration and invasion properties were evaluated by RNA interference (RNAi). RESULTS The positive rates of BCAT1 protein expression in normal epithelia, low-to-moderate grade atypical hyperplasia tissues, high-grade atypical hyperplasia tissues and NPC tissues were 23.6% (17/72), 75% (18/24), 88.9% (8/9) and 88.8% (71/80), respectively. Only one SNP site in exon1 was detected, and 42.4% (12/28) of the NPC tissues displayed the amplification of microsatellite loci in BCAT1. C-Myc could directly bind to the c-Myc binding site in promoter region of BCAT1 and up-regulate its expression. The mRNA and protein of c-Myc and BCAT1 were co-expressed in 53.6% (15/28) and 59.1% (13/22) of NPC tissues, respectively, and BCAT1 mRNA expression was also down-regulated in c-Myc knockdown cell lines. In addition, BCAT1 knockdown cells demonstrated reduced proliferation and decreased cell migration and invasion abilities. CONCLUSIONS Our study indicates that gene amplification and c-Myc up-regulation are responsible for BCAT1 overexpression in primary NPC, and overexpression of BCAT1 induces cell proliferation, migration and invasion. The results suggest that BCAT1 may be a novel molecular target for the diagnosis and treatment of NPC.
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13
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Establishment of mouse teratocarcinomas stem cells line and screening genes responsible for malignancy. PLoS One 2012; 7:e43955. [PMID: 22952821 PMCID: PMC3432059 DOI: 10.1371/journal.pone.0043955] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 07/27/2012] [Indexed: 02/06/2023] Open
Abstract
The sequential transplantation of embryonal carcinoma cells in vivo can accelerate the growth and malignancy of teratocarcinomas. However, the possible molecular mechanisms in this process that reflect cancer formation in the early stage are largely unknown and. To identify which genes are associated with the changes of malignancy of teratocarcinomas, we established a tumorigenesis model in which teratocarcinoma were induced via injecting embryonic stem cells into immuno-deficiency mice, isolating teratocarcinoma stem cell from a teratocarcinoma in serum-free culture medium and injecting teratocarcinoma stem cells into immune-deficient mice continuously. By using high-throughput deep sequence technology, we identified 26 differentially expressed genes related to the changes of characteristics of teratocarcinoma stem cell in which 18 out of 26 genes were down-regulated and 8 genes were up-regulated. Among these genes, several tumor-related genes such as Gata3, Arnt and Tdgf1, epigenetic associated genes such as PHC1 and Uty were identified. Pathway enrichment analysis result revealed that Wnt signaling pathway, primary immunodeficiency pathway, antigen processing and presentation pathway and allograft rejection pathway were involved in the teratocarcinoma tumorigenesis (corrected p value<0.05). In summary, our study established a tumorigenesis model and proposed some candidate genes and signaling pathways that may play a key role in the early stage of cancer occurrence.
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14
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Abstract
The perception of wine flavor and aroma is the result of a multitude of interactions between a large number of chemical compounds and sensory receptors. Compounds interact and combine and show synergistic (i.e., the presence of one compound enhances the perception of another) and antagonistic (a compound suppresses the perception of another) interactions. The chemical profile of a wine is derived from the grape, the fermentation microflora (in particular the yeast Saccharomyces cerevisiae), secondary microbial fermentations that may occur, and the aging and storage conditions. Grape composition depends on the varietal and clonal genotype of the vine and on the interaction of the genotype and its phenotype with many environmental factors which, in wine terms, are usually grouped under the concept of "terroir" (macro, meso and microclimate, soil, topography). The microflora, and in particular the yeast responsible for fermentation, contributes to wine aroma by several mechanisms: firstly by utilizing grape juice constituents and biotransforming them into aroma- or flavor-impacting components, secondly by producing enzymes that transform neutral grape compounds into flavor-active compounds, and lastly by the de novo synthesis of many flavor-active primary (e.g., ethanol, glycerol, acetic acid, and acetaldehyde) and secondary metabolites (e.g., esters, higher alcohols, fatty acids). This review aims to present an overview of the formation of wine flavor and aroma-active components, including the varietal precursor molecules present in grapes and the chemical compounds produced during alcoholic fermentation by yeast, including compounds directly related to ethanol production or secondary metabolites. The contribution of malolactic fermentation, ageing, and maturation on the aroma and flavor of wine is also discussed.
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Abstract
myc genes are associated with a wide variety of human cancers including most types of nervous system tumors. While the mechanisms by which myc overexpression causes tumorigenesis are multifaceted and have yet to be clearly elucidated, they are at least in part related to endogenous myc function in normal cells. Knockout (KO) of either c-myc or N-myc genes in neural stem and precursor cells (NSC) driven by nestin-cre impairs mouse brain growth and mutation of N-myc also causes microcephaly in humans in Feingold Syndrome. To further define myc function in NSC and nervous system development, we created a double KO (DKO) for c- and N-myc using nestin-cre. The DKO mice display profoundly impaired overall brain growth associated with decreased cell cycling and migration of NSC, which are strikingly decreased in number. The DKO brain also exhibits specific changes in gene expression including downregulation of genes involved in protein and nucleotide metabolism, mitosis, and chromatin structure as well as upregulation of genes associated with differentiation. Together these data support a model of nervous system tumorigenesis in which excess myc aberrantly locks in a developmentally active chromatin state characterized by overactive cell cycling, and metabolism as well as blocked differentiation.
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16
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Styger G, Jacobson D, Bauer FF. Identifying genes that impact on aroma profiles produced by Saccharomyces cerevisiae and the production of higher alcohols. Appl Microbiol Biotechnol 2011; 91:713-30. [DOI: 10.1007/s00253-011-3237-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 03/15/2011] [Accepted: 03/15/2011] [Indexed: 10/18/2022]
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17
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de Bont JM, Kros JM, Passier MMCJ, Reddingius RE, Sillevis Smitt PAE, Luider TM, den Boer ML, Pieters R. Differential expression and prognostic significance of SOX genes in pediatric medulloblastoma and ependymoma identified by microarray analysis. Neuro Oncol 2008; 10:648-60. [PMID: 18577562 DOI: 10.1215/15228517-2008-032] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The objective of this study was to identify differentially expressed and prognostically important genes in pediatric medulloblastoma and pediatric ependymoma by Affymetrix microarray analysis. Among the most discriminative genes, three members of the SOX transcription factor family were differentially expressed. Both SOX4 and SOX11 were significantly overexpressed in medulloblastoma (median, 11-fold and 5-fold, respectively) compared with ependymoma and normal cerebellum. SOX9 had greater expression in ependymoma (median, 16-fold) compared with normal cerebellum and medulloblastoma (p<0.001 for all comparisons). The differential expression of the SOX genes was confirmed at the protein level by immunohistochemical analysis. Survival analysis of the most discriminative probe sets for each subgroup showed that 35 and 13 probe sets were predictive of survival in patients with medulloblastoma and ependymoma, respectively. There was a trend toward better survival with increasing SOX4 expression in medulloblastoma. SOX9 expression was predictive for favorable outcome in ependymoma. The mRNA levels of BCAT1, a mediator of amino acid breakdown, were higher (median, 15-fold) in medulloblastoma patients with metastases compared with those without metastasized disease (p<0.01). However, the correlation between BCAT1 expression and metastatic medulloblastoma could not be confirmed at the protein level. The potential prognostic effect of the genes associated with outcome should be evaluated in ongoing studies using larger groups of patients. Furthermore, our findings support further analysis of the functional properties of the selected genes, especially SOX4 and BCAT1 for medulloblastoma and SOX9 for ependymoma, to evaluate the use of these genes as potential tumor markers, prognostic markers, and drug targets in pediatric brain tumors.
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Affiliation(s)
- Judith M de Bont
- Department of Pediatric Oncology and Hematology, Erasmus MC Sophia Children's Hospital, University Medical Center Rotterdam, Rotterdam, The Netherlands
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18
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Burns KH, Owens GE, Ogbonna SC, Nilson JH, Matzuk MM. Expression profiling analyses of gonadotropin responses and tumor development in the absence of inhibins. Endocrinology 2003; 144:4492-507. [PMID: 12959983 DOI: 10.1210/en.2003-0476] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Transgenic mice with engineered disruptions in bidirectional endocrine signaling between the pituitary and gonad have shed light on the specific effects of the loss of function of gonadotropins and inhibins. These models are valuable tools for studying ovarian biology because they phenocopy specific pathological states and have variations in ovarian tissue composition that allow us to identify genes expressed in specific cell types. We have used emerging mRNA expression profiling technologies to gain a more comprehensive view of genes that are expressed in the mammalian ovary and adrenal gland in the FSHbeta and inhibin alpha knockout mouse models. Oligonucleotide array hybridization experiments using Affymetrix GeneChip technology and NIA 15K murine cDNA microarray studies identified hundreds of transcripts differentially expressed compared with wild type, over 30 of which were selected for further characterization by Northern blot analyses. Additionally, we performed in situ hybridization studies to localize 10 mRNAs, melanocyte-specific gene 1, amino acid transporter SN2, overexpressed and amplified in teratocarcinoma (Bcat1), Forkhead box protein FOXO1, 24p3, vascular cell adhesion molecule, epiregulin, Bcl2-like10, PC3B, and retinoblastoma binding protein 7. These 10 genes have expression patterns and postulated functions suggesting that they mediate important processes in the physiology and pathology of ovarian and adrenal tissue.
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Affiliation(s)
- Kathleen H Burns
- Department of Pathology, Baylor College of Medicine, Houston, Texas 77030, USA
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19
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Lin HM, Kaneshige M, Zhao L, Zhang X, Hanover JA, Cheng SY. An isoform of branched-chain aminotransferase is a novel co-repressor for thyroid hormone nuclear receptors. J Biol Chem 2001; 276:48196-205. [PMID: 11574535 DOI: 10.1074/jbc.m104320200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The functions of thyroid hormone receptors (TRs) are regulated by a host of co-regulatory proteins. Tissue-specific expression of these co-regulators leads to distinct expression patterns and regulation of thyroid hormone (T3) target genes in tissues. Previously we have found that human colon carcinoma RKO cells exhibit strong T3-independent transcriptional activity. We therefore searched for co-regulatory proteins in RKO cells using a yeast two-hybrid system with the intact TRbeta1 as bait. One of the three positive clones, designated as P3, was identified to be an isoform of human mitochondria branched-chain aminotransferase (BCATm). P3 was a spliced variant of BCATm with an internal 12-amino acid deletion near the carboxyl-terminal region and was abundantly expressed in RKO cells. The expressed protein localized both to the mitochondria and the nucleus of transfected CV1 cells. P3 physically interacted with TRbeta1 in a T3-independent manner that led to the inhibition in binding of TRbeta1 to thyroid hormone-responsive element. P3 not only enhanced the repressor activity of the unliganded TR but also repressed the ligand-dependent activation of TR. This repression was reversed by treatment of cells with trichostatin A, suggesting that in addition to the inhibition of DNA binding, the repression activity of P3 on TR may also be mediated by histone deacetylase activity. Thus, unlike the currently known co-repressors, P3 is a novel ligand-independent co-repressor for TR.
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Affiliation(s)
- H M Lin
- Gene Regulation Section, Laboratory of Molecular Biology, NCI and Laboratory of Cell Biochemistry and Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0851, USA
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20
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Than NG, Sümegi B, Than GN, Bellyei S, Bohn H. Molecular cloning and characterization of placental tissue protein 18 (PP18a)/human mitochondrial branched-chain aminotransferase (BCATm) and its novel alternatively spliced PP18b variant. Placenta 2001; 22:235-43. [PMID: 11170829 DOI: 10.1053/plac.2000.0603] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Five different insert-length cDNAs encoding for soluble placental tissue protein 18 (PP18) variants were isolated by screening a human placental cDNA library using monospecific anti-PP18 serum. Sequence analysis of the longest clone showed that the insert contains an open reading frame encoding for a 392 residue-long protein with a 27 amino acid mitochondrial targeting sequence. The mature protein-designated PP18a-is 41.264 kDa consisting of 365 residues and is identical to the previously isolated and characterized PP18 antigen described in 1985. We also found a new, alternatively spliced cDNA encoding for a 300 residue-long, 33.776 kDa protein, which was designated PP18b. Alignment search of the protein databank showed that PP18a is almost entirely identical to the human mitochondrial branched-chain aminotransferase, while PP18b is its newly discovered splicing variant. We detected the two PP18 variants in normal adult and fetal human tissues besides the mitochondrial (only PP18a) and cytosolic (only PP18b) fractions of term placenta with chemiluminescence Western blot analysis. The 41 kDa PP18a variant was expressed ubiquitously, while the 33 kDa PP18b variant was found in smaller amounts in nearly all tissues. Trace amounts of the variants were present in the sera of non-pregnant healthy controls, as well as in pregnant women, but there was no real change in serum levels during pregnancy. In conclusion, PP18 variants are not specific for the placenta. Aminotransferase activity of placental origin PP18 antigens was verified by structural analysis and by a coupled branched-chain aminotransferase/glutamate dehydrogenase assay.
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Affiliation(s)
- N G Than
- Institute of Biochemistry, Medical School, University of Pécs, Edesanyák 17, H-7624 Pécs, Hungary.
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Eden A, Benvenisty N. Involvement of branched-chain amino acid aminotransferase (Bcat1/Eca39) in apoptosis. FEBS Lett 1999; 457:255-61. [PMID: 10471790 DOI: 10.1016/s0014-5793(99)01054-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The branched-chain amino acid aminotransferase, Bcat1/Eca39, catalyzes the first step of branched-chain amino acid catabolism. Bcat1/Eca39 was originally isolated from a c-myc-induced tumor and was proven to be a direct target for c-Myc regulation. The gene is highly conserved in evolution and disruption of its yeast homolog affects cell growth. To assess the role of Bcat1/Eca39 in mammalian cells, we overexpressed Bcat1/Eca39 in murine cells and studied effects on cell growth. Overexpression of Bcat1/Eca39 had no apparent effect on the proliferation of cells grown with high serum concentrations, but under serum deprivation conditions, led to a decrease in cell viability. Cell death under these conditions displayed apoptotic features. The branched-chain keto acid, alpha-ketoisocaproate, a metabolite of leucine catabolism produced by BCAT1/ECA39, was previously found to inhibit cell growth. We show that alpha-ketoisocaproate can induce rapid apoptotic cell death. This observation suggests that the growth inhibitory effect of BCAT1/ECA39 and its apoptosis promoting effect may be mediated by the levels of the products of BCAT1/ECA39 activity, namely, branched-chain keto acids.
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Affiliation(s)
- A Eden
- Department of Genetics, Institute of Life Sciences, The Hebrew University of Jerusalem, Givat-Ram, Jerusalem, Israel
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