1
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Zhu Q, Du L, Wu J, Li J, Lin Z. Walrycin B, as a novel separase inhibitor, exerts potent anticancer efficacy in a mouse xenograft model. Biochem Pharmacol 2024; 229:116502. [PMID: 39173842 DOI: 10.1016/j.bcp.2024.116502] [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: 04/30/2024] [Revised: 07/30/2024] [Accepted: 08/20/2024] [Indexed: 08/24/2024]
Abstract
Proper chromosome segregation during cell division relies on the timely dissolution of chromosome cohesion. Separase (EC3.4.22.49), a cysteine protease, plays a critical role in mitosis by cleaving the kleisin subunit of cohesin, thereby presenting a promising target for cancer therapy. However, challenges in isolating active human separase suitable for high-throughput screening have limited the identification of effective inhibitors. Here, we conducted a high-throughput screening of small-molecule inhibitors using the protease domain of Chaetomium thermophilum separase (ctSPD), which not only shares significant sequence similarity with human separase but is also readily available. After conducting a primary screening of a library containing 9,172 compounds and subsequent validation using human separase, we identified walrycin B and its analogs, toxoflavin, 3-methyltoxoflavin, and 3-phenyltoxoflavin, as potent inhibitors of human separase. Subsequent microscale thermophoresis assays and molecular dynamics simulations revealed that walrycin B binds to the active site of separase and competes with substrates for binding. Additionally, cell-based studies showed that walrycin B and its analogs effectively induce cell cycle arrest at the M phase, activate apoptosis, and ultimately lead to cell death in mitosis. Finally, in a mouse xenograft model, walrycin B exhibited significant antitumor efficacy with minimal side effects. Together, these findings highlight the therapeutic potential of walrycin B for cancer treatment and its utility as a chemical tool in future studies involving separase.
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Affiliation(s)
- Qinwei Zhu
- College of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Liyang Du
- College of Pharmacy and Medical Technology, Putian University, Putian 351100, China
| | - Juhong Wu
- College of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Jinyu Li
- College of Chemistry, Fuzhou University, Fuzhou 350108, China.
| | - Zhonghui Lin
- College of Chemistry, Fuzhou University, Fuzhou 350108, China.
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Bai X, Smith HE, Golden A. Identification of genetic suppressors for a BSCL2 lipodystrophy pathogenic variant in Caenorhabditis elegans. Dis Model Mech 2024; 17:dmm050524. [PMID: 38454882 PMCID: PMC11051982 DOI: 10.1242/dmm.050524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 03/04/2024] [Indexed: 03/09/2024] Open
Abstract
Seipin (BSCL2), a conserved endoplasmic reticulum protein, plays a critical role in lipid droplet (LD) biogenesis and in regulating LD morphology, pathogenic variants of which are associated with Berardinelli-Seip congenital generalized lipodystrophy type 2 (BSCL2). To model BSCL2 disease, we generated an orthologous BSCL2 variant, seip-1(A185P), in Caenorhabditis elegans. In this study, we conducted an unbiased chemical mutagenesis screen to identify genetic suppressors that restore embryonic viability in the seip-1(A185P) mutant background. A total of five suppressor lines were isolated and recovered from the screen. The defective phenotypes of seip-1(A185P), including embryonic lethality and impaired eggshell formation, were significantly suppressed in each suppressor line. Two of the five suppressor lines also alleviated the enlarged LDs in the oocytes. We then mapped a suppressor candidate gene, lmbr-1, which is an ortholog of human limb development membrane protein 1 (LMBR1). The CRISPR/Cas9 edited lmbr-1 suppressor alleles, lmbr-1(S647F) and lmbr-1(P314L), both significantly suppressed embryonic lethality and defective eggshell formation in the seip-1(A185P) background. The newly identified suppressor lines offer valuable insights into potential genetic interactors and pathways that may regulate seipin in the lipodystrophy model.
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Affiliation(s)
- Xiaofei Bai
- Department of Biology, University of Florida, Gainesville, FL 32610, USA
- Genetics Institute, University of Florida, Gainesville, FL 32610, USA
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Harold E. Smith
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Andy Golden
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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Sorensen Turpin CG, Sloan D, LaForest M, Klebanow LU, Mitchell D, Severson AF, Bembenek JN. Securin Regulates the Spatiotemporal Dynamics of Separase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.12.571338. [PMID: 38168402 PMCID: PMC10760073 DOI: 10.1101/2023.12.12.571338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Separase is a key regulator of the metaphase to anaphase transition with multiple functions. Separase cleaves cohesin to allow chromosome segregation and localizes to vesicles to promote exocytosis in mid-anaphase. The anaphase promoting complex/cyclosome (APC/C) activates separase by ubiquitinating its inhibitory chaperone, securin, triggering its degradation. How this pathway controls the exocytic function of separase has not been investigated. During meiosis I, securin is degraded over several minutes, while separase rapidly relocalizes from kinetochore structures at the spindle and cortex to sites of action on chromosomes and vesicles at anaphase onset. The loss of cohesin coincides with the relocalization of separase to the chromosome midbivalent at anaphase onset. APC/C depletion prevents separase relocalization, while securin depletion causes precocious separase relocalization. Expression of non-degradable securin inhibits chromosome segregation, exocytosis, and separase localization to vesicles but not to the anaphase spindle. We conclude that APC/C mediated securin degradation controls separase localization. This spatiotemporal regulation will impact the effective local concentration of separase for more precise targeting of substrates in anaphase.
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Affiliation(s)
- Christopher G. Sorensen Turpin
- Current Address: Department of Obstetrics and Gynecology, C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Dillon Sloan
- Current Address: Department of Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Marian LaForest
- Current Address: Columbia University, Herbert Irving Comprehensive Cancer Center, NYC, New York, United States of America
| | | | - Diana Mitchell
- Current Address: Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Aaron F. Severson
- Current Address: Center for Gene Regulation in Health and Disease and Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, Ohio, United States of America
| | - Joshua N. Bembenek
- Current Address: Department of Obstetrics and Gynecology, C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, Michigan, United States of America
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Bai X, Smith HE, Golden A. Identification of Genetic Suppressors for a Berardinelli-Seip Congenital Generalized Lipodystrophy Type 2 (BSCL2) Pathogenic Variant in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.22.559059. [PMID: 37790539 PMCID: PMC10542546 DOI: 10.1101/2023.09.22.559059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Maintaining the metabolic homeostasis of fatty acids is crucial for human health. Excess fatty acids are stored in lipid droplets (LDs), the primary energy reservoir that helps regulate fat and lipid homeostasis in nearly all cell types. Seipin (BSCL2), a conserved endoplasmic reticulum protein, plays a critical role in LD biogenesis and regulating LD morphology. Pathogenic variants of seipin are associated with multiple human genetic diseases, including Berardinelli-Seip Congenital Generalized Lipodystrophy Type 2 (BSCL2). However, the cellular and molecular mechanisms by which dysfunctional seipin leads to these diseases remain unclear. To model BSCL2 disease, we generated an orthologous BSCL2 pathogenic variant seip-1(A185P) using CRISPR/Cas9 genome editing in Caenorhabditis elegans . This variant led to severe developmental and cellular defects, including embryonic lethality, impaired eggshell formation, and abnormally enlarged LDs. We set out to identify genetic determinants that could suppress these defective phenotypes in the seip-1(A185P) mutant background. To this end, we conducted an unbiased chemical mutagenesis screen to identify genetic suppressors that restore embryonic viability in the seip-1(A185P) mutant background. A total of five suppressor lines were isolated and recovered from the screen. The defective phenotypes of seip-1(A185P) , including embryonic lethality and impaired eggshell formation, were significantly suppressed in each suppressor line. Two of the five suppressor lines also alleviated the enlarged LDs in the oocytes. We then mapped a suppressor candidate gene, R05D3.2 (renamed as lmbr-1 ), which is an ortholog of human LMBR1 (limb development membrane protein 1). The CRISPR/Cas9 edited lmbr-1 suppressor alleles, lmbr-1(Ser647Phe) and lmbr-1(Pro314Leu) , both significantly suppressed embryonic lethality and defective eggshell formation in the seip-1(A185P) background. The newly identified suppressor lines offer valuable insights into potential genetic interactors and pathways that may regulate seipin in the lipodystrophy model.
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Boukaba A, Wu Q, Liu J, Chen C, Liang J, Li J, Strunnikov A. Mapping separase-mediated cleavage in situ. NAR Genom Bioinform 2022; 4:lqac085. [PMID: 36415827 PMCID: PMC9673495 DOI: 10.1093/nargab/lqac085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 10/13/2022] [Accepted: 10/25/2022] [Indexed: 11/21/2022] Open
Abstract
Separase is a protease that performs critical functions in the maintenance of genetic homeostasis. Among them, the cleavage of the meiotic cohesin during meiosis is a key step in producing gametes in eukaryotes. However, the exact chromosomal localization of this proteolytic cleavage was not addressed due to the lack of experimental tools. To this end, we developed a method based on monoclonal antibodies capable of recognizing the predicted neo-epitopes produced by separase-mediated proteolysis in the RAD21 and REC8 cohesin subunits. To validate the epigenomic strategy of mapping cohesin proteolysis, anti-RAD21 neo-epitopes antibodies were used in ChIP-On-ChEPseq analysis of human cells undergoing mitotic anaphase. Second, a similar analysis applied for mapping of REC8 cleavage in germline cells in Macaque showed a correlation with a subset of alpha-satellites and other repeats, directly demonstrating that the site-specific mei-cohesin proteolysis hotspots are coincident but not identical with centromeres. The sequences for the corresponding immunoglobulin genes show a convergence of antibodies with close specificity. This approach could be potentially used to investigate cohesin ring opening events in other chromosomal locations, if applied to single cells.
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Affiliation(s)
- Abdelhalim Boukaba
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Qiongfang Wu
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Jian Liu
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Cheng Chen
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Jierong Liang
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Jingjing Li
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Alexander V Strunnikov
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
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Sloan DE, Bembenek JN. Endogenous expression and localization of HIS-72::mTurquoise2 in C. elegans. MICROPUBLICATION BIOLOGY 2021; 2021:10.17912/micropub.biology.000471. [PMID: 34604717 PMCID: PMC8482033 DOI: 10.17912/micropub.biology.000471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/11/2021] [Accepted: 09/13/2021] [Indexed: 11/05/2022]
Abstract
To generate a non-red/green fluorescent fusion histone protein in C. elegans, we have generated a C-terminal mTurquoise2-tagged HIS-72 at the endogenous locus using CRISPR. We found that HIS-72::mTurquoise2 localizes in a similar pattern to the previously published HIS-72::GFP strain.
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Zhang Y, Su H, Wudu M, Ren H, Xu Y, Zhang Q, Jiang J, Wang Q, Jiang X, Zhang B, Liu Z, Zou Z, Qiu X. TBC1 domain family member 23 interacts with Ras-related protein Rab-11A to promote poor prognosis of non-small-cell lung cancer via β1-integrin. J Cell Mol Med 2021; 25:8821-8835. [PMID: 34363324 PMCID: PMC8435452 DOI: 10.1111/jcmm.16841] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 07/09/2021] [Accepted: 07/26/2021] [Indexed: 11/27/2022] Open
Abstract
Non‐small‐cell lung cancer (NSCLC) accounts for approximately 80% of lung cancer cases. TBC1D23, a member of the TBC/RABGAP family, is widely expressed in human tissues; however, its role in NSCLC is currently unknown. Immunohistochemical analysis was conducted on 173 paraffin‐embedded lung tissue sections from patients with NSCLC from 2014 to 2018 at the First Affiliated Hospital of China Medical University. MTT, colony formation assay, cell cycle assay, scratch assay, transwell assay, Western blotting and real‐time PCR were employed on multiple NSCLC cell lines modified to knock down or overexpress TBC1D23/RAB11A. Immunoprecipitation, immunoprecipitation‐mass spectrometry, immunofluorescence and flow cytometry were performed to explore the interaction between TBC1D23 and RAB11A and TBC1D23 involvement in the interaction between RAB11A and β1 integrin in the para‐nucleus. TBC1D23 was correlated with tumour size, differentiation degree, metastasis, TNM stage and poor prognosis. TBC1D23 was involved in the interaction between RAB11A and β1 integrin in the para‐nucleus, thus activating the β1 integrin/FAK/ERK signalling pathway to promote NSCLC. Furthermore, TBC1D23 promoted NSCLC progression by inducing cell proliferation, migration and invasion. This study indicated the relationship between TBC1D23 expression and the adverse clinicopathological characteristics of patients with NSCLC, suggesting that TBC1D23 may be an important target for NSCLC treatment.
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Affiliation(s)
- Yao Zhang
- Department of Pathology, First Affiliated Hospital College and of Basic Medical Sciences China Medical University, Shenyang, China
| | - Hongbo Su
- Department of Pathology, First Affiliated Hospital College and of Basic Medical Sciences China Medical University, Shenyang, China
| | - Muli Wudu
- Department of Pathology, Basic Medical Sciences, Xinjiang Medical University, Urumqi, China
| | - Hongjiu Ren
- Department of Pathology, First Affiliated Hospital College and of Basic Medical Sciences China Medical University, Shenyang, China
| | - Yitong Xu
- Department of Pathology, First Affiliated Hospital College and of Basic Medical Sciences China Medical University, Shenyang, China
| | - Qingfu Zhang
- Department of Pathology, First Affiliated Hospital College and of Basic Medical Sciences China Medical University, Shenyang, China
| | - Jun Jiang
- Department of Pathology, First Affiliated Hospital College and of Basic Medical Sciences China Medical University, Shenyang, China
| | - Qiongzi Wang
- Department of Pathology, First Affiliated Hospital College and of Basic Medical Sciences China Medical University, Shenyang, China
| | - Xizi Jiang
- Department of Pathology, First Affiliated Hospital College and of Basic Medical Sciences China Medical University, Shenyang, China
| | - Bo Zhang
- Department of Pathology, First Affiliated Hospital College and of Basic Medical Sciences China Medical University, Shenyang, China
| | - Zongang Liu
- Department of Thoracic Surgery, The First Hospital of China Medical University, Shenyang, China
| | - Zifang Zou
- Department of Thoracic Surgery, Shengjing Hospital of China Medical University, Shenyang, China
| | - Xueshan Qiu
- Department of Pathology, First Affiliated Hospital College and of Basic Medical Sciences China Medical University, Shenyang, China
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Ding Y, Li Y, Chhetri G, Peng X, Wu J, Wang Z, Zhao B, Zhao W, Li X. Parkinson's Disease Causative Mutation in Vps35 Disturbs Tetherin Trafficking to Cell Surfaces and Facilitates Virus Spread. Cells 2021; 10:746. [PMID: 33800686 PMCID: PMC8066283 DOI: 10.3390/cells10040746] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/19/2021] [Accepted: 03/25/2021] [Indexed: 12/11/2022] Open
Abstract
Parkinson's disease (PD) is the most common neurodegenerative movement disorder, characterized by progressive loss of dopaminergic neurons in the substantia nigra, intraneuronal deposition of misfolded proteins known as Lewy bodies, and chronic neuroinflammation. PD can arise from monogenic mutations, but in most cases, the etiology is unclear. Viral infection is gaining increasing attentions as a trigger of PD. In this study, we investigated whether the PD-causative 620 aspartate (D) to asparagine (N) mutation in the vacuolar protein sorting 35 ortholog (Vps35) precipitated herpes simplex virus (HSV) infection. We observed that ectopic expression of Vps35 significantly reduced the proliferation and release of HSV-1 virions; the D620N mutation rendered Vps35 a partial loss of such inhibitory effects. Tetherin is a host cell protein capable of restricting the spread of encapsulated viruses including HSV-1 and SARS-Cov-2, both of which are implicated in the development of parkinsonism. Compared with cells overexpressing wildtype Vps35, cells expressing mutant Vps35 with D620N had less Tetherin on cell surfaces. Real-time and static cell imaging revealed that Tetherin recycled through Vps35-positive endosomes. Expression of Vps35 with D620N reduced endosomal dynamics and frequency of motile Tetherin-containing vesicles, a sign of defective production of recycling carriers. Our study suggests that the D620N mutation in Vps35 hinders Tetherin trafficking to cell surfaces and facilitates virus spread.
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Affiliation(s)
- Yingzhuo Ding
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China; (Y.D.); (Y.L.); (G.C.); (X.P.); (J.W.); (Z.W.); (B.Z.); (W.Z.)
| | - Yan Li
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China; (Y.D.); (Y.L.); (G.C.); (X.P.); (J.W.); (Z.W.); (B.Z.); (W.Z.)
| | - Gaurav Chhetri
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China; (Y.D.); (Y.L.); (G.C.); (X.P.); (J.W.); (Z.W.); (B.Z.); (W.Z.)
| | - Xiaoxin Peng
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China; (Y.D.); (Y.L.); (G.C.); (X.P.); (J.W.); (Z.W.); (B.Z.); (W.Z.)
| | - Jing Wu
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China; (Y.D.); (Y.L.); (G.C.); (X.P.); (J.W.); (Z.W.); (B.Z.); (W.Z.)
| | - Zejian Wang
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China; (Y.D.); (Y.L.); (G.C.); (X.P.); (J.W.); (Z.W.); (B.Z.); (W.Z.)
| | - Bo Zhao
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China; (Y.D.); (Y.L.); (G.C.); (X.P.); (J.W.); (Z.W.); (B.Z.); (W.Z.)
| | - Wenjuan Zhao
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China; (Y.D.); (Y.L.); (G.C.); (X.P.); (J.W.); (Z.W.); (B.Z.); (W.Z.)
| | - Xueyi Li
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China; (Y.D.); (Y.L.); (G.C.); (X.P.); (J.W.); (Z.W.); (B.Z.); (W.Z.)
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
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Abstract
Separase is a large cysteine protease in eukaryotes and has crucial roles in many cellular processes, especially chromosome segregation during mitosis and meiosis, apoptosis, DNA damage repair, centrosome disengagement and duplication, spindle stabilization and elongation. It dissolves the cohesion between sister chromatids by cleaving one of the subunits of the cohesin ring for chromosome segregation. The activity of separase is tightly controlled at many levels, through direct binding of inhibitory proteins as well as posttranslational modification. Dysregulation of separase activity is linked to cancer and genome instability, making it a target for drug discovery. One of the best-known inhibitors of separase is securin, which has been identified in yeast, plants, and animals. Securin forms a tight complex with separase and potently inhibits its catalytic activity. Recent structures of the separase-securin complex have revealed the molecular mechanism for the inhibitory activity of securin. A segment of securin is bound in the active site of separase, thereby blocking substrate binding. Securin itself is not cleaved by separase as its binding mode is not compatible with catalysis. Securin also has extensive interactions with separase outside the active site, consistent with its function as a chaperone to stabilize this enzyme.
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Affiliation(s)
- Shukun Luo
- Department of Biological Sciences, Columbia University, New York, NY, 10027, USA
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, NY, 10027, USA.
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Intertwined Functions of Separase and Caspase in Cell Division and Programmed Cell Death. Sci Rep 2020; 10:6159. [PMID: 32273538 PMCID: PMC7145830 DOI: 10.1038/s41598-020-63081-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 03/05/2020] [Indexed: 11/30/2022] Open
Abstract
Timely sister chromatid separation, promoted by separase, is essential for faithful chromosome segregation. Separase is a member of the CD clan of cysteine proteases, which also includes the pro-apoptotic enzymes known as caspases. We report a role for the C. elegans separase SEP-1, primarily known for its essential activity in cell division and cortical granule exocytosis, in developmentally programmed cell death when the predominant pro-apoptotic caspase CED-3 is compromised. Loss of SEP-1 results in extra surviving cells in a weak ced-3(-) mutant, and suppresses the embryonic lethality of a mutant defective for the apoptotic suppressor ced-9/Bcl-2 implicating SEP-1 in execution of apoptosis. We also report apparent non-apoptotic roles for CED-3 in promoting germ cell proliferation, meiotic chromosome disjunction, egg shell formation, and the normal rate of embryonic development. Moreover, loss of the soma-specific (CSP-3) and germline-specific (CSP-2) caspase inhibitors result in CED-3-dependent suppression of embryonic lethality and meiotic chromosome non-disjunction respectively, when separase function is compromised. Thus, while caspases and separases have evolved different substrate specificities associated with their specialized functions in apoptosis and cell division respectively, they appear to have retained the residual ability to participate in both processes, supporting the view that co-option of components in cell division may have led to the innovation of programmed cell suicide early in metazoan evolution.
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Zhang N, Sarkar AK, Li F, Demerzhan SA, Gilbertson SR, Pati D. Stability and pharmacokinetics of separase inhibitor-Sepin-1 in Sprague-Dawley rats. Biochem Pharmacol 2020; 174:113808. [PMID: 31930961 DOI: 10.1016/j.bcp.2020.113808] [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: 11/11/2019] [Accepted: 01/09/2020] [Indexed: 11/29/2022]
Abstract
Separase, a sister chromatid cohesion-resolving enzyme, is an oncogene and overexpressed in many human cancers. Sepin-1 (2,2-dimethyl-5-nitro-2H-benzimidazole-1,3-dioxide) is a potent separase inhibitor that impedes cancer cell growth, cell migration, and wound healing, suggesting that Sepin-1 possesses a great potential to target separase-overexpressing tumors. As a part of the IND-enabling studies to bring Sepin-1 to clinic, herein we report the results from a 28-day repeat-dose pharmacokinetic study of Sepin-1 in rats. Sepin-1 was intravenously administered to Sprague-Dawley rats once daily for 28 days at three different (5, 10, and 20 mg/kg) doses. Blood samples were collected after administration of doses on days 1 and 28. Sepin-1 is unstable and isomerizes in basic solutions, but it is stable in acidic buffer such as citrate-buffered saline (pH 4.0). UHPLC-MS analysis indicated Sepin-1 was rapidly metabolized in vivo. One of the major metabolites was an amine adduct of 2,2-dimethyl-5-nitro-2H-benzimidazole (named Sepin-1.55). The concentration of Sepin-1.55 in blood samples was Sepin-1 dose-dependent and used for pharmacokinetic analysis of Sepin-1. Tmax was approximately 5-15 min. The data suggest that no Sepin-1 accumulation occurred from daily repeat dosing and similar exposures on the first and final day of dosing. Data also suggest a gender difference, namely that female rats have more exposure and slower clearance than male rats. The data support that Sepin-1 is a potential drug candidate that can be further developed to treat Separase-overexpressing human tumors.
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Affiliation(s)
- Nenggang Zhang
- Texas Children's Cancer Center, Departments of Pediatrics and Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Asis K Sarkar
- Texas Children's Cancer Center, Departments of Pediatrics and Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Feng Li
- Center for Drug Discovery, Departments of Pathology and Immunology, Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX, USA
| | | | | | - Debananda Pati
- Texas Children's Cancer Center, Departments of Pediatrics and Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.
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Toxicity study of separase inhibitor-Sepin-1 in Sprague-Dawley rats. Pathol Res Pract 2019; 216:152730. [PMID: 31784093 DOI: 10.1016/j.prp.2019.152730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/17/2019] [Accepted: 11/10/2019] [Indexed: 01/01/2023]
Abstract
Sepin-1 is a small compound that inhibits enzymatic activity of Separase and growth of cancer cells. As part of the IND-enabling studies to develop Sepin-1 as a chemotherapeutic agent, herein we have profiled the toxicity of Sepin-1 in Sprague-Dawley rats in a good laboratory practice (GLP) setting. The maximum tolerated dose (MTD) of Sepin-1 in rats is 40 mg/kg in single dose study and 20 mg/kg in the study dosed for 7 consecutive days. The toxicity study consists of two parts-Main Study and Recovery Study. Sepin-1 with 0 (control), 5 (low dose), 10 (median dose), and 20 (high dose) mg/kg was administered by bolus intravenous injection to rats once daily for 28 consecutive days. The animals in the Main Study were euthanized on Day 29, whereas animals in the Recovery Study were allowed to recover for 28 days following the 28-day Sepin-1 dose before they were euthanized on Day 29 of the off-dose period. Although the effects of Sepin-1 at low and median doses are minimal, hematological analysis shows that high-dose Sepin-1 is associated with decrease of red blood cells and hemoglobin, and increase in the number of reticulocytes and platelets as well as mean corpuscular volume. Clinical chemistry indicates that Sepin-1 causes increase of total bilirubin and decrease of creatine kinase. Histopathology analysis indicates Sepin-1 results in minimal bone marrow erythroid hyperplasia, minimal to moderate splenic extramedullary hematopoiesis, minimal splenic lymphoid depletion, minimal to mild thymic lymphoid depletion, and minimal to mild mandibular lymph node lymphoid hyperplasia in male and female rats in the Main Study. Those abnormal changes are Sepin-1 dose-dependent and mostly reversible after a 28-day recovery period in animals from the Recovery Study. Based on our results, we conclude that Sepin-1 at pharmacologic doses (5-10 mg/kg) is well tolerable, with no significant rates of mortality or morbidity, and can further be developed as a potential new drug to treat Separase-overexpressed tumors.
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13
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Li F, Zhang N, Gorantla S, Gilbertson SR, Pati D. The Metabolism of Separase Inhibitor Sepin-1 in Human, Mouse, and Rat Liver Microsomes. Front Pharmacol 2018; 9:313. [PMID: 29867452 PMCID: PMC5949348 DOI: 10.3389/fphar.2018.00313] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 03/19/2018] [Indexed: 01/02/2023] Open
Abstract
Separase, a known oncogene, is widely overexpressed in numerous human tumors of breast, bone, brain, blood, and prostate. Separase is an emerging target for cancer therapy, and separase enzymatic inhibitors such as sepin-1 are currently being developed to treat separase-overexpressed tumors. Drug metabolism plays a critical role in the efficacy and safety of drug development, as well as possible drug–drug interactions. In this study, we investigated the in vitro metabolism of sepin-1 in human, mouse, and rat liver microsomes (RLM) using metabolomic approaches. In human liver microsomes (HLM), we identified seven metabolites including one cysteine–sepin-1 adduct and one glutathione–sepin-1 adduct. All the sepin-1 metabolites in HLM were also found in both mouse and RLM. Using recombinant CYP450 isoenzymes, we demonstrated that multiple enzymes contributed to the metabolism of sepin-1, including CYP2D6 and CYP3A4 as the major metabolizing enzymes. Inhibitory effects of sepin-1 on seven major CYP450s were also evaluated using the corresponding substrates recommended by the US Food and Drug Administration. Our studies indicated that sepin-1 moderately inhibits CYP1A2, CYP2C19, and CYP3A4 with IC50 < 10 μM but weakly inhibits CYP2B6, CYP2C8/9, and CYP2D6 with IC50 > 10 μM. This information can be used to optimize the structures of sepin-1 for more suitable pharmacological properties and to predict the possible sepin-1 interactions with other chemotherapeutic drugs.
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Affiliation(s)
- Feng Li
- Center for Drug Discovery, Baylor College of Medicine, Houston, TX, United States.,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States.,Advance Technology Core, Baylor College of Medicine, Houston, TX, United States
| | - Nenggang Zhang
- Texas Children's Cancer Center, Houston, TX, United States.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Siddharth Gorantla
- Texas Children's Cancer Center, Houston, TX, United States.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Scott R Gilbertson
- Department of Chemistry, University of Houston, Houston, TX, United States
| | - Debananda Pati
- Center for Drug Discovery, Baylor College of Medicine, Houston, TX, United States.,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States.,Texas Children's Cancer Center, Houston, TX, United States.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
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14
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Melesse M, Bembenek JN, Zhulin IB. Conservation of the separase regulatory domain. Biol Direct 2018; 13:7. [PMID: 29703221 PMCID: PMC5921967 DOI: 10.1186/s13062-018-0210-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 04/18/2018] [Indexed: 11/10/2022] Open
Abstract
ᅟ: We report a protein sequence analysis of the cell cycle regulatory protease, separase. The sequence and structural conservation of the C-terminal protease domain has long been recognized, whereas the N-terminal regulatory domain of separase was reported to lack detectable sequence similarity. Here we reveal significant sequence conservation of the separase regulatory domain and report a discovery of a cysteine motif (CxCxxC) conserved in major lineages of Metazoa including nematodes and vertebrates. This motif is found in a solvent exposed linker region connecting two TPR-like helical motifs. Mutation of this motif in Caenorhabditis elegans separase leads to a temperature sensitive hypomorphic protein. Conservation of this motif in organisms ranging from C. elegans to humans suggests its functional importance. REVIEWERS This article was reviewed by Lakshminarayan Iyer and Michael Galperin.
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Affiliation(s)
- Michael Melesse
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Joshua N Bembenek
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA.
| | - Igor B Zhulin
- Department of Microbiology, University of Tennessee, 1414 Cumberland Ave, Knoxville, TN, 37996, USA. .,Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
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Zhang N, Pati D. Separase Inhibitor Sepin-1 Inhibits Foxm1 Expression and Breast Cancer Cell Growth. JOURNAL OF CANCER SCIENCE & THERAPY 2018; 10:517. [PMID: 29780443 PMCID: PMC5959057 DOI: 10.4172/1948-5956.1000517] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Sepin-1, a potent non-competitive inhibitor of separase, inhibits cancer cell growth, but the mechanisms of Sepin-1-mediated growth inhibition are not fully understood. Here we report that Sepin-1 hinders growth of breast cancer cells, cell migration, and wound healing. Inhibition of cell growth induced by Sepin-1 in vitro doesn't appear to be through apoptosis but rather due to growth inhibition. Following Sepin-1 treatment caspases 3 and 7 are not activated and Poly (ADP-ribose) polymerase (Parp) is not cleaved. The expression of Forkhead box protein M1 (FoxM1), a transcription factor, and its target genes in the cell cycle, including Plk1, Cdk1, Aurora A, and Lamin B1, are reduced in a Sepin-1-dependent manner. Expressions of Raf kinase family members A-Raf, B-Raf, and C-Raf also are inhibited following treatment with Sepin-1. Raf is an intermediator in the Raf-Mek-Erk signaling pathway that phosphorylates FoxM1. Activated FoxM1 can promote its own transcription via a positive feedback loop. Sepin-1-induced downregulation of Raf and FoxM1 may inhibit expression of cell cycle-driving genes, resulting in inhibition of cell growth.
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Affiliation(s)
- Nenggang Zhang
- Department of Pediatrics, Texas Children’s Cancer Center, Baylor College of Medicine, Houston, Texas, USA
| | - Debananda Pati
- Department of Pediatrics, Texas Children’s Cancer Center, Baylor College of Medicine, Houston, Texas, USA
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