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Inhibition of nuclear export restores nuclear localization and residual tumor suppressor function of truncated SMARCB1/INI1 protein in a molecular subset of atypical teratoid/rhabdoid tumors. Acta Neuropathol 2021; 142:361-374. [PMID: 34003336 PMCID: PMC8270878 DOI: 10.1007/s00401-021-02328-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 02/08/2023]
Abstract
Loss of nuclear SMARCB1 (INI1/hSNF5/BAF47) protein expression due to biallelic mutations of the SMARCB1 tumor suppressor gene is a hallmark of atypical teratoid/rhabdoid tumors (ATRT), but the presence of cytoplasmic SMARCB1 protein in these tumors has not yet been described. In a series of 102 primary ATRT, distinct cytoplasmic SMARCB1 staining on immunohistochemistry was encountered in 19 cases (19%) and was highly over-represented in cases showing pathogenic sequence variants leading to truncation or mutation of the C-terminal part of SMARCB1 (15/19 vs. 4/83; Chi-square: 56.04, p = 1.0E−10) and, related to this, in tumors of the molecular subgroup ATRT-TYR (16/36 vs. 3/66; Chi-square: 24.47, p = 7.6E−7). Previous reports have indicated that while SMARCB1 lacks a bona fide nuclear localization signal, it harbors a masked nuclear export signal (NES) and that truncation of the C-terminal region results in unmasking of this NES leading to cytoplasmic localization. To determine if cytoplasmic localization found in ATRT is due to unmasking of NES, we generated GFP fusions of one of the SMARCB1 truncating mutations (p.Q318X) found in the tumors along with a p.L266A mutation, which was shown to disrupt the interaction of SMARCB1-NES with exportin-1. We found that while the GFP-SMARCB1(Q318X) mutant localized to the cytoplasm, the double mutant GFP-SMARCB1(Q318X;L266A) localized to the nucleus, confirming NES requirement for cytoplasmic localization. Furthermore, cytoplasmic SMARCB1(Q318X) was unable to cause senescence as determined by morphological observations and by senescence-associated β-galactosidase assay, while nuclear SMARCB1(Q318X;L266A) mutant regained this function. Selinexor, a selective exportin-1 inhibitor, was effective in inhibiting the nuclear export of SMARCB1(Q318X) and caused rapid cell death in rhabdoid tumor cells. In conclusion, inhibition of nuclear export restores nuclear localization and residual tumor suppressor function of truncated SMARCB1. Therapies aimed at preventing nuclear export of mutant SMARCB1 protein may represent a promising targeted therapy in ATRT harboring truncating C-terminal SMARCB1 mutations.
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Umschweif G, Medrihan L, McCabe KA, Sagi Y, Greengard P. Activation of the p11/SMARCA3/Neurensin-2 pathway in parvalbumin interneurons mediates the response to chronic antidepressants. Mol Psychiatry 2021; 26:3350-3362. [PMID: 33723417 PMCID: PMC8505248 DOI: 10.1038/s41380-021-01059-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 02/02/2021] [Accepted: 02/18/2021] [Indexed: 12/26/2022]
Abstract
The delayed behavioral response to chronic antidepressants depends on dynamic changes in the hippocampus. It was suggested that the antidepressant protein p11 and the chromatin remodeling factor SMARCA3 mediate this delayed response by inducing transcriptional changes in hippocampal neurons. However, what target genes are regulated by the p11/SMARCA3 complex to mediate the behavioral response to antidepressants, and what cell type mediates these molecular changes remain unknown. Here we report that the p11/SMARCA3 complex represses Neurensin-2 transcription in hippocampal parvalbumin-expressing interneurons after chronic treatment with Selective Serotonin Reuptake Inhibitors (SSRI). The behavioral response to antidepressants requires upregulation of p11, accumulation of SMARCA3 in the cell nucleus, and a consequent repression of Neurensin-2 transcription in these interneurons. We elucidate a functional role for p11/SMARCA3/Neurensin-2 pathway in regulating AMPA-receptor signaling in parvalbumin-expressing interneurons, a function that is enhanced by chronic treatment with SSRIs. These results link SSRIs to dynamic glutamatergic changes and implicate p11/SMARCA3/Neurensin-2 pathway in the development of more specific and efficient therapeutic strategies for neuropsychiatric disorders.
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Affiliation(s)
- Gali Umschweif
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY, USA
| | - Lucian Medrihan
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY, USA
| | - Kathryn A McCabe
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY, USA
| | - Yotam Sagi
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY, USA.
| | - Paul Greengard
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY, USA
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Voisin MR, Ovenden C, Tsang DS, Gupta AA, Huang A, Gao AF, Diamandis P, Almeida JP, Gentili F. Atypical Teratoid/Rhabdoid Sellar Tumor in an Adult with a Familial History of a Germline SMARCB1 Mutation: Case Report and Review of the Literature. World Neurosurg 2019; 127:336-345. [PMID: 31004861 DOI: 10.1016/j.wneu.2019.04.083] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 12/15/2022]
Abstract
BACKGROUND Adult sellar atypical teratoid/rhabdoid tumor (ATRT) is a rare diagnosis that has recently been shown to be a clinicopathologically and genetically distinct variant of ATRT occurring almost exclusively in middle-aged women. Although up to one third of pediatric ATRT is caused by a familial syndrome, no previous cases of a familial adult sellar ATRT have been reported. We present the first case report of a familial germline mutation causing adult sellar ATRT and a literature review of 29 previously reported cases of sporadic adult sellar ATRT. CASE DESCRIPTION A 51-year-old woman with a family history of brain tumors spanning 3 generations presented with visual decline and was diagnosed with an adult sellar ATRT. Genetic studies showed a heterozygous splice-site loss-of-function mutation of the INI1 gene in exon 7. Treatment included endoscopic endonasal biopsy, craniospinal irradiation, and focal tumor boost, followed by adjuvant chemotherapy. CONCLUSIONS This is the first case report of a familial germline mutation causing adult sellar ATRT. This article highlights the importance of a thorough family history and genetic testing in these individuals and reviews the current genetics, histopathology, and multidisciplinary treatment approach in this rare condition.
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Affiliation(s)
- Mathew R Voisin
- Department of Neurosurgery, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada.
| | - Chris Ovenden
- Adelaide Medical School, University of Adelaide, Adelaide, Australia
| | - Derek S Tsang
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Abha A Gupta
- Department of Medical Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Annie Huang
- Pediatric Brain Tumor Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Andrew F Gao
- Department of Pathology, University Health Network, Toronto, Ontario, Canada
| | - Phedias Diamandis
- Department of Pathology, University Health Network, Toronto, Ontario, Canada
| | - Joao P Almeida
- Department of Neurosurgery, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Fred Gentili
- Department of Neurosurgery, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
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Xie G, Chen H, Jia D, Shu Z, Palmer WH, Huang YC, Zeng X, Hou SX, Jiao R, Deng WM. The SWI/SNF Complex Protein Snr1 Is a Tumor Suppressor in Drosophila Imaginal Tissues. Cancer Res 2016; 77:862-873. [PMID: 27923836 DOI: 10.1158/0008-5472.can-16-0963] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 11/02/2016] [Accepted: 11/18/2016] [Indexed: 12/17/2022]
Abstract
Components of the SWI/SNF chromatin-remodeling complex are among the most frequently mutated genes in various human cancers, yet only SMARCB1/hSNF5, a core member of the SWI/SNF complex, is mutated in malignant rhabdoid tumors (MRT). How SMARCB1/hSNF5 functions differently from other members of the SWI/SNF complex remains unclear. Here, we use Drosophila imaginal epithelial tissues to demonstrate that Snr1, the conserved homolog of human SMARCB1/hSNF5, prevents tumorigenesis by maintaining normal endosomal trafficking-mediated signaling cascades. Removal of Snr1 resulted in neoplastic tumorigenic overgrowth in imaginal epithelial tissues, whereas depletion of any other members of the SWI/SNF complex did not induce similar phenotypes. Unlike other components of the SWI/SNF complex that were detected only in the nucleus, Snr1 was observed in both the nucleus and the cytoplasm. Aberrant regulation of multiple signaling pathways, including Notch, JNK, and JAK/STAT, was responsible for tumor progression upon snr1-depletion. Our results suggest that the cytoplasmic Snr1 may play a tumor suppressive role in Drosophila imaginal tissues, offering a foundation for understanding the pivotal role of SMARCB1/hSNF5 in suppressing MRT during early childhood. Cancer Res; 77(4); 862-73. ©2017 AACR.
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Affiliation(s)
- Gengqiang Xie
- Department of Biological Science, Florida State University, Tallahassee, Florida
| | - Hanqing Chen
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, the Chinese Academy of Sciences, Beijing, China
| | - Dongyu Jia
- Department of Biological Science, Florida State University, Tallahassee, Florida
| | - Zhiqiang Shu
- Department of Biological Science, Florida State University, Tallahassee, Florida
| | - William Hunt Palmer
- Department of Biological Science, Florida State University, Tallahassee, Florida
| | - Yi-Chun Huang
- Department of Biological Science, Florida State University, Tallahassee, Florida
| | - Xiankun Zeng
- The Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Steven X Hou
- The Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Renjie Jiao
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, the Chinese Academy of Sciences, Beijing, China. .,Sino-French Hoffmann Institute, Guangzhou Medical University, Guangzhou, China
| | - Wu-Min Deng
- Department of Biological Science, Florida State University, Tallahassee, Florida.
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Garcia-Gutierrez P, Juarez-Vicente F, Wolgemuth DJ, Garcia-Dominguez M. Pleiotrophin antagonizes Brd2 during neuronal differentiation. J Cell Sci 2014; 127:2554-64. [PMID: 24695857 DOI: 10.1242/jcs.147462] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Bromodomain-containing protein 2 (Brd2) is a BET family chromatin adaptor required for expression of cell-cycle-associated genes and therefore involved in cell cycle progression. Brd2 is expressed in proliferating neuronal progenitors, displays cell-cycle-stimulating activity and, when overexpressed, impairs neuronal differentiation. Paradoxically, Brd2 is also detected in differentiating neurons. To shed light on the role of Brd2 in the transition from cell proliferation to differentiation, we had previously looked for proteins that interacted with Brd2 upon induction of neuronal differentiation. Surprisingly, we identified the growth factor pleiotrophin (Ptn). Here, we show that Ptn antagonized the cell-cycle-stimulating activity associated with Brd2, thus enhancing induced neuronal differentiation. Moreover, Ptn knockdown reduced neuronal differentiation. We analyzed Ptn-mediated antagonism of Brd2 in a cell differentiation model and in two embryonic processes associated with the neural tube: spinal cord neurogenesis and neural crest migration. Finally, we investigated the mechanisms of Ptn-mediated antagonism and determined that Ptn destabilizes the association of Brd2 with chromatin. Thus, Ptn-mediated Brd2 antagonism emerges as a modulation system accounting for the balance between cell proliferation and differentiation in the vertebrate nervous system.
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Affiliation(s)
- Pablo Garcia-Gutierrez
- Stem Cells Department, Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER) (Consejo Superior de Investigaciones Cientificas (CSIC), Junta de Andalucía, Universidad de Sevilla, Universidad Pablo de Olavide), Seville 41092, Spain
| | - Francisco Juarez-Vicente
- Stem Cells Department, Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER) (Consejo Superior de Investigaciones Cientificas (CSIC), Junta de Andalucía, Universidad de Sevilla, Universidad Pablo de Olavide), Seville 41092, Spain
| | - Debra J Wolgemuth
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA
| | - Mario Garcia-Dominguez
- Stem Cells Department, Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER) (Consejo Superior de Investigaciones Cientificas (CSIC), Junta de Andalucía, Universidad de Sevilla, Universidad Pablo de Olavide), Seville 41092, Spain
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