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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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Kumar P, Cheng H, Paudyal S, Nakamura LV, Zhang N, Li JT, Sasidharan R, Jeong M, Pati D. Haploinsufficiency of cohesin protease, Separase, promotes regeneration of hematopoietic stem cells in mice. Stem Cells 2020; 38:1624-1636. [PMID: 32997844 DOI: 10.1002/stem.3280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 07/23/2020] [Accepted: 08/31/2020] [Indexed: 11/09/2022]
Abstract
Cohesin recently emerged as a new regulator of hematopoiesis and leukemia. In addition to cohesin, whether proteins that regulate cohesin's function have any direct role in hematopoiesis and hematologic diseases have not been fully examined. Separase, encoded by the ESPL1 gene, is an important regulator of cohesin's function. Canonically, protease activity of Separase resolves sister chromatid cohesion by cleaving cohesin subunit-Rad21 at the onset of anaphase. Using a Separase haploinsufficient mouse model, we have uncovered a novel role of Separase in hematopoiesis. We report that partial disruption of Separase distinctly alters the functional characteristics of hematopoietic stem/progenitor cells (HSPCs). Although analyses of peripheral blood and bone marrow of Espl1+/Hyp mice broadly displayed unperturbed hematopoietic parameters during normal hematopoiesis, further probing of the composition of early hematopoietic cells in Espl1+/Hyp bone marrow revealed a mild reduction in the frequencies of the Lin- Sca1+ Kit- (LSK) or LSK CD48+ CD150- multipotent hematopoietic progenitors population without a significant change in either long-term or short-term hematopoietic stem cells (HSCs) subsets at steady state. Surprisingly, however, we found that Separase haploinsufficiency promotes regeneration activity of HSCs in serial in vivo repopulation assays. In vitro colony formation assays also revealed an enhanced serial replating capacity of hematopoietic progenitors isolated from Espl1+/Hyp mice. Microarray analysis of differentially expressed genes showed that Separase haploinsufficiency in HSCs (SP-KSL) leads to enrichment of gene signatures that are upregulated in HSCs compared to committed progenitors and mature cells. Taken together, our findings demonstrate a key role of Separase in promoting hematopoietic regeneration of HSCs.
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Affiliation(s)
- Praveen Kumar
- Texas Childrens Cancer Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Haizi Cheng
- Texas Childrens Cancer Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Samridhdi Paudyal
- Texas Childrens Cancer Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Lanelle V Nakamura
- Texas Childrens Cancer Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Nenggang Zhang
- Texas Childrens Cancer Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Jessica T Li
- Texas Childrens Cancer Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | | | - Mira Jeong
- Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Debananda Pati
- Texas Childrens Cancer Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
- Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
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Spiess B, Kleiner H, Flach J, Fabarius A, Saussele S, Hofmann WK, Seifarth W. Separase activity distribution can be a marker of major molecular response and proliferation of CD34 + cells in TKI-treated chronic myeloid leukemia patients. Ann Hematol 2020; 99:991-1006. [PMID: 32253454 PMCID: PMC7196950 DOI: 10.1007/s00277-020-04007-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 03/18/2020] [Indexed: 11/28/2022]
Abstract
Separase, a cysteine endopeptidase, is a key player in mitotic sister chromatid separation, replication fork dynamics, and DNA repair. Aberrant expression and/or altered separase proteolytic activity are associated with aneuploidy, tumorigenesis, and disease progression. Since genomic instability and clonal evolution are hallmarks of progressing chronic myeloid leukemia (CML), we have comparatively examined separase proteolytic activity in TKI-treated chronic phase CML. Separase proteolytic activity was analyzed on single cell level in 88 clinical samples and in 14 healthy controls by a flow cytometric assay. In parallel, BCR-ABL1 gene expression and replication fork velocity were measured by qRT-PCR and DNA fiber assays, respectively. The separase activity distribution (SAD) value indicating the occurrence of MNCs with elevated separase proteolytic activity within samples was found to positively correlate with BCR-ABL1 gene expression levels and loss of MMR (relapse) throughout routine BCR-ABL1 monitoring. Analyses of CD34+ cells and MNCs fractionized by flow cytometric cell sorting according to their separase activity levels (H- and L-fractions) revealed that CD34+ cells with elevated separase activity levels (H-fractions) displayed enhanced proliferation/viability when compared with cells with regular (L-fraction) separase activity (mean 3.3-fold, p = 0.0011). BCR-ABL1 gene expression positivity prevailed in MNC H-fractions over L-fractions (42% vs. 8%, respectively). Moreover, expanding CD34+ cells of H-fractions showed decreased replication fork velocity compared with cells of L-fractions (p < 0.0001). Our data suggests an association between high separase activity, residual BCR-ABL1 gene expression, and enhanced proliferative capacity in hematopoietic cells within the leukemic niche of TKI-treated chronic phase CML.
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Affiliation(s)
- Birgit Spiess
- Department of Hematology and Oncology, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany. .,Hämatologie und Onkologie, III. Medizinische Klinik, Wissenschaftliches Labor, Universitätsklinikum Mannheim GmbH, Pettenkoferstraße 22, 68169, Mannheim, Germany.
| | - Helga Kleiner
- Department of Hematology and Oncology, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Johanna Flach
- Department of Hematology and Oncology, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Alice Fabarius
- Department of Hematology and Oncology, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Susanne Saussele
- Department of Hematology and Oncology, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Wolf-Karsten Hofmann
- Department of Hematology and Oncology, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Wolfgang Seifarth
- Department of Hematology and Oncology, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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Ruppenthal S, Kleiner H, Nolte F, Fabarius A, Hofmann WK, Nowak D, Seifarth W. Increased separase activity and occurrence of centrosome aberrations concur with transformation of MDS. PLoS One 2018; 13:e0191734. [PMID: 29370237 PMCID: PMC5784974 DOI: 10.1371/journal.pone.0191734] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 01/10/2018] [Indexed: 01/15/2023] Open
Abstract
ESPL1/separase, a cysteine endopeptidase, is a key player in centrosome duplication and mitotic sister chromatid separation. Aberrant expression and/or altered separase proteolytic activity are associated with centrosome amplification, aneuploidy, tumorigenesis and disease progression. Since centrosome alterations are a common and early detectable feature in patients with myelodysplastic syndrome (MDS) and cytogenetic aberrations play an important role in disease risk stratification, we examined separase activity on single cell level in 67 bone marrow samples obtained from patients with MDS, secondary acute myeloid leukemia (sAML), de novo acute myeloid leukemia (AML) and healthy controls by a flow cytometric separase activity assay. The separase activity distribution (SAD) value, a calculated measure for the occurrence of cells with prominent separase activity within the analyzed sample, was tested for correlation with the centrosome, karyotype and gene mutation status. We found higher SAD values in bone marrow cells of sAML patients than in corresponding cells of MDS patients. This concurred with an increased incidence of aberrant centrosome phenotypes in sAML vs. MDS samples. No correlation was found between SAD values and the karyotype/gene mutation status. During follow-up of four MDS patients we observed increasing SAD values after transformation to sAML, in two patients SAD values decreased during azacitidine therapy. Cell culture experiments employing MDS-L cells as an in vitro model of MDS revealed that treatment with rigosertib, a PLK1 inhibitor and therapeutic drug known to induce G2/M arrest, results in decreased SAD values. In conclusion, the appearance of cells with unusual high separase activity levels, as indicated by increased SAD values, concurs with the transformation of MDS to sAML and may reflect separase dysregulation potentially contributing to clonal evolution during MDS progression. Separase activity measurement may therefore be useful as a novel additional molecular marker for disease monitoring.
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Affiliation(s)
- Sabrina Ruppenthal
- Department of Hematology and Oncology, University Hospital Mannheim, Heidelberg University, Mannheim, Germany
- * E-mail:
| | - Helga Kleiner
- Department of Hematology and Oncology, University Hospital Mannheim, Heidelberg University, Mannheim, Germany
| | - Florian Nolte
- Department of Hematology and Oncology, University Hospital Mannheim, Heidelberg University, Mannheim, Germany
| | - Alice Fabarius
- Department of Hematology and Oncology, University Hospital Mannheim, Heidelberg University, Mannheim, Germany
| | - Wolf-Karsten Hofmann
- Department of Hematology and Oncology, University Hospital Mannheim, Heidelberg University, Mannheim, Germany
| | - Daniel Nowak
- Department of Hematology and Oncology, University Hospital Mannheim, Heidelberg University, Mannheim, Germany
| | - Wolfgang Seifarth
- Department of Hematology and Oncology, University Hospital Mannheim, Heidelberg University, Mannheim, Germany
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Prinzhorn W, Stehle M, Kleiner H, Ruppenthal S, Müller MC, Hofmann WK, Fabarius A, Seifarth W. c-MYB is a transcriptional regulator of ESPL1/Separase in BCR-ABL-positive chronic myeloid leukemia. Biomark Res 2016; 4:5. [PMID: 26937281 PMCID: PMC4774018 DOI: 10.1186/s40364-016-0059-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/24/2016] [Indexed: 01/05/2023] Open
Abstract
Background Genomic instability and clonal evolution are hallmarks of progressing chronic myeloid leukemia (CML). Recently, we have shown that clonal evolution and blast crisis correlate with altered expression and activity of Separase, a cysteine endopeptidase that is a mitotic key player in chromosomal segregation and centriole duplication. Hyperactivation of Separase in human hematopoietic cells has been linked to a feedback mechanism that posttranslationally stimulates Separase proteolytic activity after imatinib therapy-induced reduction of Separase protein levels. Methods and Results In search for potential therapy-responsive transcriptional mechanisms we have investigated the role of the transcription factor c-MYB for Separase expression in CML cell lines (LAMA-84, K562, BV-173) and in clinical samples. Quantitative RT-PCR and Western blot immunostaining experiments revealed that c-MYB expression levels are decreased in an imatinib-dependent manner and positively correlate with Separase expression levels in cell lines and in clinical CML samples. RNA silencing of c-MYB expression in CML cell lines resulted in reduced Separase protein levels. Gelshift and ChIP assays confirmed that c-MYB binds to a putative c-MYB binding sequence located within the ESPL1 promoter. Conclusions Our data suggest that ESPL1/Separase is a regulatory target of c-MYB. Therefore, c-MYB, known to be required for BCR-ABL-dependent transformation of hematopoietic progenitors and leukemogenesis, may also control the Separase-dependent fidelity of mitotic chromosomal segregation and centriole duplication essential for maintenance of genomic stability.
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Affiliation(s)
- Wiltrud Prinzhorn
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
| | - Michael Stehle
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
| | - Helga Kleiner
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
| | - Sabrina Ruppenthal
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
| | - Martin C Müller
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
| | - Wolf-Karsten Hofmann
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
| | - Alice Fabarius
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
| | - Wolfgang Seifarth
- III. Medizinische Klinik (Hämatologie und Onkologie), Wissenschaftliches Labor, Medizinische Fakultät Mannheim der Universität Heidelberg, Pettenkofer Str. 22, 68169 Mannheim, Germany
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Haaß W, Kleiner H, Müller MC, Hofmann WK, Fabarius A, Seifarth W. Measurement of separase proteolytic activity in single living cells by a fluorogenic flow cytometry assay. PLoS One 2015; 10:e0133769. [PMID: 26267133 PMCID: PMC4534294 DOI: 10.1371/journal.pone.0133769] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 07/01/2015] [Indexed: 12/27/2022] Open
Abstract
ESPL1/Separase, an endopeptidase, is required for centrosome duplication and separation of sister-chromatides in anaphase of mitosis. Overexpression and deregulated proteolytic activity of Separase as frequently observed in human cancers is associated with the occurrence of supernumerary centrosomes, chromosomal missegregation and aneuploidy. Recently, we have hypothesized that increased Separase proteolytic activity in a small subpopulation of tumor cells may serve as driver of tumor heterogeneity and clonal evolution in chronic myeloid leukemia (CML). Currently, there is no quantitative assay to measure Separase activity levels in single cells. Therefore, we have designed a flow cytometry-based assay that utilizes a Cy5- and rhodamine 110 (Rh110)-biconjugated Rad21 cleavage site peptide ([Cy5-D-R-E-I-M-R]2-Rh110) as smart probe and intracellular substrate for detection of Separase enzyme activity in living cells. As measured by Cy5 fluorescence the cellular uptake of the fluorogenic peptide was fast and reached saturation after 210 min of incubation in human histiocytic lymphoma U937 cells. Separase activity was recorded as the intensity of Rh110 fluorescence released after intracellular peptide cleavage providing a linear signal gain within a 90–180 min time slot. Compared to conventional cell extract-based methods the flow cytometric assay delivers equivalent results but is more reliable, bypasses the problem of vague loading controls and unspecific proteolysis associated with whole cell extracts. Especially suited for the investigaton of blood- and bone marrow-derived hematopoietic cells the flow cytometric Separase assay allows generation of Separase activity profiles that tell about the number of Separase positive cells within a sample i.e. cells that currently progress through mitosis and about the range of intercellular variation in Separase activity levels within a cell population. The assay was used to quantify Separase proteolytic activity in leukemic cell lines and peripheral blood samples from leukemia patients.
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MESH Headings
- Cell Line, Tumor
- Flow Cytometry
- Humans
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/blood
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/enzymology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Mitosis/genetics
- Proteolysis
- Separase/biosynthesis
- Separase/blood
- Separase/genetics
- Single-Cell Analysis
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Affiliation(s)
- Wiltrud Haaß
- III. Medizinische Universitätsklinik, (Hämatologie und Onkologie), Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
| | - Helga Kleiner
- III. Medizinische Universitätsklinik, (Hämatologie und Onkologie), Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
| | - Martin C. Müller
- III. Medizinische Universitätsklinik, (Hämatologie und Onkologie), Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
| | - Wolf-Karsten Hofmann
- III. Medizinische Universitätsklinik, (Hämatologie und Onkologie), Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
| | - Alice Fabarius
- III. Medizinische Universitätsklinik, (Hämatologie und Onkologie), Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
| | - Wolfgang Seifarth
- III. Medizinische Universitätsklinik, (Hämatologie und Onkologie), Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
- * E-mail:
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Haaß W, Kleiner H, Weiß C, Haferlach C, Schlegelberger B, Müller MC, Hehlmann R, Hofmann WK, Fabarius A, Seifarth W. Clonal Evolution and Blast Crisis Correlate with Enhanced Proteolytic Activity of Separase in BCR-ABL b3a2 Fusion Type CML under Imatinib Therapy. PLoS One 2015; 10:e0129648. [PMID: 26087013 PMCID: PMC4472749 DOI: 10.1371/journal.pone.0129648] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 05/07/2015] [Indexed: 11/18/2022] Open
Abstract
Unbalanced (major route) additional cytogenetic aberrations (ACA) at diagnosis of chronic myeloid leukemia (CML) indicate an increased risk of progression and shorter survival. Moreover, newly arising ACA under imatinib treatment and clonal evolution are considered features of acceleration and define failure of therapy according to the European LeukemiaNet (ELN) recommendations. On the basis of 1151 Philadelphia chromosome positive chronic phase patients of the randomized CML-study IV, we examined the incidence of newly arising ACA under imatinib treatment with regard to the p210BCR-ABL breakpoint variants b2a2 and b3a2. We found a preferential acquisition of unbalanced ACA in patients with b3a2 vs. b2a2 fusion type (ratio: 6.3 vs. 1.6, p = 0.0246) concurring with a faster progress to blast crisis for b3a2 patients (p = 0.0124). ESPL1/Separase, a cysteine endopeptidase, is a key player in chromosomal segregation during mitosis. Separase overexpression and/or hyperactivity has been reported from a wide range of cancers and cause defective mitotic spindles, chromosome missegregation and aneuploidy. We investigated the influence of p210BCR-ABL breakpoint variants and imatinib treatment on expression and proteolytic activity of Separase as measured with a specific fluorogenic assay on CML cell lines (b2a2: KCL-22, BV-173; b3a2: K562, LAMA-84). Despite a drop in Separase protein levels an up to 5.4-fold increase of Separase activity under imatinib treatment was observed exclusively in b3a2 but not in b2a2 cell lines. Mimicking the influence of imatinib on BV-173 and LAMA-84 cells by ESPL1 silencing stimulated Separase proteolytic activity in both b3a2 and b2a2 cell lines. Our data suggest the existence of a fusion type-related feedback mechanism that posttranslationally stimulates Separase proteolytic activity after therapy-induced decreases in Separase protein levels. This could render b3a2 CML cells more prone to aneuploidy and clonal evolution than b2a2 progenitors and may therefore explain the cytogenetic results of CML patients.
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MESH Headings
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- Antineoplastic Agents/therapeutic use
- Blast Crisis/enzymology
- Blast Crisis/genetics
- Blast Crisis/pathology
- Cell Line, Tumor
- Chromosome Aberrations
- Chromosome Breakage
- Clonal Evolution
- Fusion Proteins, bcr-abl/genetics
- Humans
- Imatinib Mesylate/therapeutic use
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/enzymology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Middle Aged
- Proteolysis
- Separase/metabolism
- Young Adult
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Affiliation(s)
- Wiltrud Haaß
- III. Medizinische Universitätsklinik (Hämatologie und Onkologie), Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
| | - Helga Kleiner
- III. Medizinische Universitätsklinik (Hämatologie und Onkologie), Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
| | - Christel Weiß
- Abteilung Medizinische Statistik und Biomathematik, Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
| | | | | | - Martin C. Müller
- III. Medizinische Universitätsklinik (Hämatologie und Onkologie), Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
| | - Rüdiger Hehlmann
- III. Medizinische Universitätsklinik (Hämatologie und Onkologie), Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
| | - Wolf-Karsten Hofmann
- III. Medizinische Universitätsklinik (Hämatologie und Onkologie), Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
| | - Alice Fabarius
- III. Medizinische Universitätsklinik (Hämatologie und Onkologie), Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
| | - Wolfgang Seifarth
- III. Medizinische Universitätsklinik (Hämatologie und Onkologie), Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim, Germany
- * E-mail:
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8
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Zhang N, Scorsone K, Ge G, Kaffes CC, Dobrolecki LE, Mukherjee M, Lewis MT, Berg S, Stephan CC, Pati D. Identification and Characterization of Separase Inhibitors (Sepins) for Cancer Therapy. ACTA ACUST UNITED AC 2014; 19:878-89. [PMID: 24525869 DOI: 10.1177/1087057114520972] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 01/03/2014] [Indexed: 11/15/2022]
Abstract
Separase is an endopeptidase that cleaves cohesin subunit Rad21, facilitating the repair of DNA damage during interphase and the resolution of sister chromatid cohesion at anaphase. Separase activity is negatively regulated by securin and Cdk1-cyclin B in vivo. Separase overexpression is reported in a broad range of human tumors, and its overexpression in mouse models results in tumorigenesis. To elucidate further the mechanism of separase function and to test if inhibition of overexpressed separase can be used as a strategy to inhibit tumor-cell proliferation, small-molecule inhibitors of separase enzyme are essential. Here, we report a high-throughput screening for separase inhibitors (Sepins). We developed a fluorogenic separase assay using rhodamine 110-conjugated Rad21 peptide as substrate and screened a small-molecule compound library. We identified a noncompetitive inhibitor of separase called Sepin-1 that inhibits separase enzymatic activity with a half maximal inhibitory concentration (IC50) of 14.8 µM. Sepin-1 can inhibit the growth of human cancer cell lines and breast cancer xenograft tumors in mice by inhibiting cell proliferation and inducing apoptosis. The sensitivity to Sepin-1 in most cases is positively correlated to the level of separase in both cancer cell lines and tumors.
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Affiliation(s)
- Nenggang Zhang
- Texas Children's Cancer Center, and Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Kathleen Scorsone
- Texas Children's Cancer Center, and Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Gouqing Ge
- Texas Children's Cancer Center, and Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Caterina C Kaffes
- Texas Children's Cancer Center, and Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Lacey E Dobrolecki
- Lester & Sue Smith Breast Center, and Departments of Molecular and Cellular Biology and Radiology, Baylor College of Medicine, Houston, TX, USA
| | - Malini Mukherjee
- Texas Children's Cancer Center, and Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Michael T Lewis
- Lester & Sue Smith Breast Center, and Departments of Molecular and Cellular Biology and Radiology, Baylor College of Medicine, Houston, TX, USA
| | - Stacey Berg
- Texas Children's Cancer Center, and Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | | | - Debananda Pati
- Texas Children's Cancer Center, and Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
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Panigrahi AK, Pati D. Higher-order orchestration of hematopoiesis: is cohesin a new player? Exp Hematol 2012; 40:967-73. [PMID: 23022223 PMCID: PMC3595174 DOI: 10.1016/j.exphem.2012.09.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 09/10/2012] [Accepted: 09/21/2012] [Indexed: 12/20/2022]
Abstract
Hematopoiesis-the process that generates distinct lineage-committed blood cells from a single multipotent hematopoietic stem cell-is a complex process of cellular differentiation regulated by a set of dynamic transcriptional programs. Cytokines and growth factors, transcription factors, chromatin remodeling, and modifying enzymes have been suggested to enact critical roles during hematopoiesis, leading to the development of myeloid, lymphoid, erythroid and platelet precursors. How is such a complex process orchestrated? Is there a higher order of hematopoiesis regulation? These are some of the unresolved questions in the field of hematopoiesis. Here, we suggest that cohesin, which is known to mediate chromosomal cohesion between sister chromatids, may have a central role in the orchestration of hematopoiesis and serve as a master transcriptional regulator.
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Affiliation(s)
- Anil K Panigrahi
- Texas Children's Cancer Center, Department of Pediatric Hematology/Oncology, Baylor College of Medicine, Houston, TX 77030, USA.
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Haaß W, Stehle M, Nittka S, Giehl M, Schrotz-King P, Fabarius A, Hofmann WK, Seifarth W. The proteolytic activity of separase in BCR-ABL-positive cells is increased by imatinib. PLoS One 2012; 7:e42863. [PMID: 22870341 PMCID: PMC3411713 DOI: 10.1371/journal.pone.0042863] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 07/13/2012] [Indexed: 01/10/2023] Open
Abstract
Separase, an endopeptidase required for the separation of sister-chromatides in mitotic anaphase, triggers centriole disengagement during centrosome duplication. In cancer, separase is frequently overexpressed, pointing to a functional role as an aneuploidy promoter associated with centrosomal amplification and genomic instability. Recently, we have shown that centrosomal amplification and subsequent chromosomal aberrations are a hallmark of chronic myeloid leukemia (CML), increasing from chronic phase (CP) toward blast crisis (BC). Moreover, a functional linkage of p210BCR-ABL tyrosine kinase activity with centrosomal amplification and clonal evolution has been established in long-term cell culture experiments. Unexpectedly, therapeutic doses of imatinib (IM) did not counteract; instead induced similar centrosomal alterations in vitro. We investigated the influence of IM and p210BCR-ABL on Separase as a potential driver of centrosomal amplification in CML. Short-term cell cultures of p210BCR-ABL-negative (NHDF, UROtsa, HL-60, U937), positive (K562, LAMA-84) and inducible (U937p210BCR-ABL/c6 (Tet-ON)) human cell lines were treated with therapeutic doses of IM and analyzed by qRT-PCR, Western blot analysis and quantitative Separase activity assays. Decreased Separase protein levels were observed in all cells treated with IM in a dose dependent manner. Accordingly, in all p210BCR-ABL-negative cell lines, decreased proteolytic activity of Separase was found. In contrast, p210BCR-ABL-positive cells showed increased Separase proteolytic activity. This activation of Separase was consistent with changes in the expression levels of Separase regulators (Separase phosphorylation at serine residue 1126, Securin, CyclinB1 and PP2A). Our data suggest that regulation of Separase in IM-treated BCR-ABL-positive cells occurs on both the protein expression and the proteolytic activity levels. Activation of Separase proteolytic activity exclusively in p210BCR-ABL-positive cells during IM treatment may act as a driving force for centrosomal amplification, contributing to genomic instability, clonal evolution and resistance in CML.
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MESH Headings
- Antineoplastic Agents/pharmacology
- Benzamides
- Blast Crisis/drug therapy
- Blast Crisis/enzymology
- Blast Crisis/genetics
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Cyclin B1/genetics
- Cyclin B1/metabolism
- Drug Resistance, Neoplasm/drug effects
- Drug Resistance, Neoplasm/genetics
- Endopeptidases/genetics
- Endopeptidases/metabolism
- Fusion Proteins, bcr-abl/genetics
- Fusion Proteins, bcr-abl/metabolism
- Genomic Instability/drug effects
- Genomic Instability/genetics
- HL-60 Cells
- Humans
- Imatinib Mesylate
- K562 Cells
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/enzymology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Neoplasm Proteins/genetics
- Neoplasm Proteins/metabolism
- Phosphorylation/drug effects
- Phosphorylation/genetics
- Piperazines/pharmacology
- Protein Phosphatase 2/genetics
- Protein Phosphatase 2/metabolism
- Proteolysis
- Pyrimidines/pharmacology
- Securin
- Separase
- U937 Cells
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Affiliation(s)
- Wiltrud Haaß
- Department of Hematology and Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany
| | - Michael Stehle
- Department of Hematology and Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany
| | - Stefanie Nittka
- Department of Clinical Chemistry, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany
| | - Michelle Giehl
- Department of Hematology and Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany
| | - Petra Schrotz-King
- National Center for Tumor Diseases (NCT), German Cancer Center (DKFZ), Heidelberg, Germany
| | - Alice Fabarius
- Department of Hematology and Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany
| | - Wolf-Karsten Hofmann
- Department of Hematology and Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany
| | - Wolfgang Seifarth
- Department of Hematology and Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany
- * E-mail:
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Abstract
The early detection of many human diseases is crucial if they are to be treated successfully. Therefore, the development of imaging techniques that can facilitate early detection of disease is of high importance. Changes in the levels of enzyme expression are known to occur in many diseases, making their accurate detection at low concentrations an area of considerable active research. Activatable fluorescent probes show immense promise in this area. If properly designed they should exhibit no signal until they interact with their target enzyme, reducing the level of background fluorescence and potentially endowing them with greater sensitivity. The mechanisms of fluorescence changes in activatable probes vary. This review aims to survey the field of activatable probes, focusing on their mechanisms of action as well as illustrating some of the in vitro and in vivo settings in which they have been employed.
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Affiliation(s)
- Christopher R Drake
- Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, Suite 350, Box 0946, San Francisco, CA, 94107, USA
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