1
|
Andrews JC, Mok JW, Kanca O, Jangam S, Tifft C, Macnamara EF, Russell BE, Wang LK, Nelson SF, Bellen HJ, Yamamoto S, Malicdan MCV, Wangler MF. De novo variants in MRTFB have gain-of-function activity in Drosophila and are associated with a novel neurodevelopmental phenotype with dysmorphic features. Genet Med 2023; 25:100833. [PMID: 37013900 PMCID: PMC11533975 DOI: 10.1016/j.gim.2023.100833] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/22/2023] [Accepted: 03/23/2023] [Indexed: 04/03/2023] Open
Abstract
PURPOSE Myocardin-related transcription factor B (MRTFB) is an important transcriptional regulator, which promotes the activity of an estimated 300 genes but is not known to underlie a Mendelian disorder. METHODS Probands were identified through the efforts of the Undiagnosed Disease Network. Because the MRTFB protein is highly conserved between vertebrate and invertebrate model organisms, we generated a humanized Drosophila model expressing the human MRTFB protein in the same spatial and temporal pattern as the fly gene. Actin binding assays were used to validate the effect of the variants on MRTFB. RESULTS Here, we report 2 pediatric probands with de novo variants in MRTFB (p.R104G and p.A91P) and mild dysmorphic features, intellectual disability, global developmental delays, speech apraxia, and impulse control issues. Expression of the variants within wing tissues of a fruit fly model resulted in changes in wing morphology. The MRTFBR104G and MRTFBA91P variants also display a decreased level of actin binding within critical RPEL domains, resulting in increased transcriptional activity and changes in the organization of the actin cytoskeleton. CONCLUSION The MRTFBR104G and MRTFBA91P variants affect the regulation of the protein and underlie a novel neurodevelopmental disorder. Overall, our data suggest that these variants act as a gain of function.
Collapse
Affiliation(s)
- Jonathan C Andrews
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX; Jan and Dan Duncan Neurological Research Institute, Houston, TX
| | - Jung-Wan Mok
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX; Jan and Dan Duncan Neurological Research Institute, Houston, TX
| | - Oguz Kanca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX; Jan and Dan Duncan Neurological Research Institute, Houston, TX
| | - Sharayu Jangam
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX; Jan and Dan Duncan Neurological Research Institute, Houston, TX
| | - Cynthia Tifft
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD
| | - Ellen F Macnamara
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD
| | - Bianca E Russell
- Division of Genetics, Department of Pediatrics, University of California, Los Angeles, Los Angeles, CA; Institute for Precision Health, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Lee-Kai Wang
- Institute for Precision Health, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Stanley F Nelson
- Institute for Precision Health, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX; Jan and Dan Duncan Neurological Research Institute, Houston, TX; Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX; Jan and Dan Duncan Neurological Research Institute, Houston, TX; Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - May Christine V Malicdan
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD.
| | - Michael F Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX; Jan and Dan Duncan Neurological Research Institute, Houston, TX.
| |
Collapse
|
2
|
Hama A, Taga T, Tomizawa D, Muramatsu H, Hasegawa D, Adachi S, Yoshida N, Noguchi M, Sato M, Okada K, Koh K, Mitsui T, Takahashi Y, Miyamura T, Hashii Y, Kato K, Atsuta Y, Okamoto Y. Haematopoietic cell transplantation for children with acute megakaryoblastic leukaemia without Down syndrome. Br J Haematol 2023; 201:747-756. [PMID: 36786154 DOI: 10.1111/bjh.18691] [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: 11/18/2022] [Revised: 01/19/2023] [Accepted: 01/30/2023] [Indexed: 02/15/2023]
Abstract
Patients with acute megakaryoblastic leukaemia of Down syndrome (DS-AMKL) have an excellent survival rate; however, patients with non-DS-AMKL experience poor outcomes. Therefore, this study retrospectively analysed 203 children with non-DS-AMKL who underwent their first haematopoietic cell transplantation (HCT) from 1986 to 2015 using a nationwide Japanese HCT registry data to assess HCT outcomes for non-DS-AMKL. The 5-year overall survival (OS) and event-free survival (EFS) rates were 43% and 38% respectively. The 5-year OS rate was significantly higher for patients who underwent HCT in the first complete remission (CR1, 72%) than for those in the second CR (CR2, 23%) and non-CR (16%) (p < 0.001), and for those from a human leukocyte antigen (HLA)-matched (52%) than for those from an HLA-mismatched donor (27%) (p < 0.001). Multivariate analysis for OS revealed that HCT in CR2 and non-CR was a significant risk factor (hazard ratio, 5.86; 95% confidence interval, 3.56-9.53; p < 0.001). The 3-year EFS in patients who received HCT in CR1 using reduced-intensity conditioning (RIC, 35%) was significantly lower than in those using myeloablative conditioning (busulfan-based, 71%; total body irradiation-based, 58%) (p < 0.001). Risk stratification in patients with non-DS-AMKL should be established to determine HCT indication in CR1.
Collapse
Affiliation(s)
- Asahito Hama
- Department of Haematology and Oncology, Children's Medical Centre, Japanese Red Cross Aichi Medical Centre Nagoya First Hospital, Nagoya, Japan
| | - Takashi Taga
- Department of Paediatrics, Shiga University of Medical Science, Otsu, Japan
| | - Daisuke Tomizawa
- Division of Leukaemia and Lymphoma, Children's Cancer Centre, National Centre for Child Health and Development, Tokyo, Japan
| | - Hideki Muramatsu
- Department of Paediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Daiichiro Hasegawa
- Department of Haematology/Oncology, Hyogo Prefectural Kobe Children's Hospital, Kobe, Japan
| | - Souichi Adachi
- Department of Human Health Science, Kyoto University, Kyoto, Japan
| | - Nao Yoshida
- Department of Haematology and Oncology, Children's Medical Centre, Japanese Red Cross Aichi Medical Centre Nagoya First Hospital, Nagoya, Japan
| | - Maiko Noguchi
- Department of Paediatrics, National Hospital Organization Kyushu Cancer Centre, Fukuoka, Japan
| | - Maho Sato
- Department of Haematology/Oncology, Osaka Women's and Children's Hospital, Izumi, Japan
| | - Keiko Okada
- Department of Paediatric Hematology/Oncology, Osaka City General Hospital, Osaka, Japan
| | - Katsuyoshi Koh
- Department of Haematology/Oncology, Saitama Children's Medical Centre, Saitama, Japan
| | - Tetsuo Mitsui
- Department of Paediatrics, Yamagata University Hospital, Yamagata, Japan
| | - Yoshiyuki Takahashi
- Department of Paediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takako Miyamura
- Department of Paediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yoshiko Hashii
- Department of Paediatrics, Osaka International Cancer Institute, Osaka, Japan
| | - Koji Kato
- Central Japan Cord Blood Bank, Seto, Japan
| | - Yoshiko Atsuta
- Japanese Data Centre for Haematopoietic Cell Transplantation, Nagakute, Japan.,Department of Registry Science for Transplant and Cellular Therapy, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Yasuhiro Okamoto
- Department of Paediatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| |
Collapse
|
3
|
Jiang A, Zhang S, Wang X, Li D. RBM15 condensates modulate m 6A modification of STYK1 to promote tumorigenesis. Comput Struct Biotechnol J 2022; 20:4825-4836. [PMID: 36147665 PMCID: PMC9464649 DOI: 10.1016/j.csbj.2022.08.068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 12/04/2022] Open
Abstract
RBM15 expression is recurrently upregulated in several types of malignant tissues, and its high expression level is typically associated with poor prognosis. However, whether and how RBM15 is involved in the tumor progression remains unclear. In this study, we found that overexpressing RBM15 in NIH3T3 cells was able to enhance proliferation rate in vitro and induced subcutaneous tumor formation in vivo. Moreover, we imaged the subcellular localization of RBM15 with our home-built structured illumination super-resolution microscopy, and revealed that RBM15 formed substantial condensates dispersed in the nucleus, undergoing dynamic fusion and fission activities. These condensates were partially colocalized with m6A-modified transcripts in the nucleus. In addition, we confirmed that RBM15 formed “liquid-like” droplets in a protein/salt concentration-dependent manner in vitro, and the addition of RNA further enhanced its phase-separation propensity. To identify downstream targets of RBM15, we performed meRIP-seq and RNA-seq, revealing that RBM15 preferentially bound to and promoted the m6A modification on the mRNA of Serine/threonine/tyrosine kinase 1 (STYK1), thereby enhancing its stability. The upregulated STYK1 expression caused MAPK hyperactivation, thereby leading to oncogenic transformation of NIH3T3 cells.
Collapse
Affiliation(s)
- Amin Jiang
- School of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Siwei Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Xinyu Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- Corresponding authors at: National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China (X. Wang and D. Li).
| | - Dong Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Corresponding authors at: National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China (X. Wang and D. Li).
| |
Collapse
|
4
|
Qi K, Hu X, Yu X, Cheng H, Wang C, Wang S, Wang Y, Li Y, Cao J, Pan B, Wu Q, Qiao J, Zeng L, Li Z, Xu K, Fu C. Targeting cyclin-dependent kinases 4/6 inhibits survival of megakaryoblasts in acute megakaryoblastic leukaemia. Leuk Res 2022; 120:106920. [PMID: 35872339 DOI: 10.1016/j.leukres.2022.106920] [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: 02/11/2022] [Revised: 06/19/2022] [Accepted: 07/16/2022] [Indexed: 11/16/2022]
Abstract
Acute megakaryoblastic leukaemia (AMKL) is characterized by expansion of megakaryoblasts, which are hyper-proliferative cells that fail to undergo differentiation. Insight to the cell-cycle regulation revealed important events in early or late megakaryocytes (MKs) maturation; the cyclin-dependent kinases 4 and 6 (CDK4/6) have been reported to participate in the development of progenitor megakaryocytes, mainly by promoting cell cycle progression and DNA polyploidization. However, it remains unclear whether the continuous proliferation, but not differentiation, of megakaryoblasts is related to an aberrant regulation of CDK4/6 in AMKL. Here, we found that CDK4/6 were up regulated in patients with AMKL, and persistently maintained at a high level during the differentiation of abnormal megakaryocytes in vitro, according to a database and western blot. Additionally, AMKL cells were exceptionally reliant on the cell cycle regulators CDK4 or 6, as blocking their activity using an inhibitor or short hairpin RNA (shRNA) significantly reduced the proliferation of 6133/MPL megakaryocytes, reduced DNA polyploidy, induced apoptosis, decreased the level of phosphorylated retinoblastoma protein (p-Rb), and activation of caspase 3. Additionally, CDK4/6 inhibitors and shRNA reduced the numbers of leukemia cells in the liver and bone marrow (BM), alleviated hepatosplenomegaly, and prolonged the survival of AMKL-transplanted mice. These results suggested that blocking the activity of CDK4/6 may represent an effective approach to control megakaryoblasts in AMKL.
Collapse
Affiliation(s)
- Kunming Qi
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Xueting Hu
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China
| | - Xiangru Yu
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China
| | - Hai Cheng
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Chunqing Wang
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Shujin Wang
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China
| | - Ying Wang
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Yanjie Li
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China
| | - Jiang Cao
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Bin Pan
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Qingyun Wu
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Jianlin Qiao
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Lingyu Zeng
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Zhenyu Li
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China
| | - Kailin Xu
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China.
| | - Chunling Fu
- Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China; Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; Key Laboratory of Bone Marrow Stem Cell, Jiangsu Province, Xuzhou, China.
| |
Collapse
|
5
|
Infant Acute Myeloid Leukemia: A Unique Clinical and Biological Entity. Cancers (Basel) 2021; 13:cancers13040777. [PMID: 33668444 PMCID: PMC7918235 DOI: 10.3390/cancers13040777] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 02/06/2021] [Accepted: 02/10/2021] [Indexed: 12/11/2022] Open
Abstract
Infant acute myeloid leukemia (AML) is a rare subgroup of AML of children <2 years of age. It is as frequent as infant acute lymphoblastic leukemia (ALL) but not clearly distinguished by study groups. However, infant AML demonstrates peculiar clinical and biological characteristics, and its prognosis differs from AML in older children. Acute megakaryoblastic leukemia (AMKL) is very frequent in this age group and has raised growing interest. Thus, AMKL is a dominant topic in this review. Recent genomic sequencing has contributed to our understanding of infant AML. These data demonstrated striking features of infant AML: fusion genes are able to induce AML transformation without additional cooperation, and unlike AML in older age groups there is a paucity of associated mutations. Mice modeling of these fusions showed the essential role of ontogeny in the infant leukemia phenotype compared to older children and adults. Understanding leukemogenesis may help in developing new targeted treatments to improve outcomes that are often very poor in this age group. A specific diagnostic and therapeutic approach for this age group should be investigated.
Collapse
|
6
|
Abstract
Acute megakaryoblastic leukemia (AMKL) is a rare malignancy affecting megakaryocytes, platelet-producing cells that reside in the bone marrow. Children with Down syndrome (DS) are particularly prone to developing the disease and have a different age of onset, distinct genetic mutations, and better prognosis as compared with individuals without DS who develop the disease. Here, we discuss the contributions of chromosome 21 genes and other genetic mutations to AMKL, the clinical features of the disease, and the differing features of DS- and non-DS-AMKL. Further studies elucidating the role of chromosome 21 genes in this disease may aid our understanding of how they function in other types of leukemia, in which they are frequently mutated or differentially expressed. Although researchers have made many insights into understanding AMKL, much more remains to be learned about its underlying molecular mechanisms.
Collapse
Affiliation(s)
- Maureen McNulty
- Northwestern University, Division of Hematology/Oncology, Chicago, Illinois 60611, USA
| | - John D Crispino
- Northwestern University, Division of Hematology/Oncology, Chicago, Illinois 60611, USA
| |
Collapse
|
7
|
Masetti R, Guidi V, Ronchini L, Bertuccio NS, Locatelli F, Pession A. The changing scenario of non-Down syndrome acute megakaryoblastic leukemia in children. Crit Rev Oncol Hematol 2019; 138:132-138. [PMID: 31092368 DOI: 10.1016/j.critrevonc.2019.04.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/07/2019] [Accepted: 04/09/2019] [Indexed: 01/30/2023] Open
Abstract
Pediatric non-Down-syndrome acute megakaryoblastic leukemia (non-DS-AMKL) is a heterogeneous subtype of leukemia that has historically been associated with poor prognosis. Until the advent of large-scale genomic sequencing, the management of patients with non-DS-AMKL was very difficult due to the absence of reliable biological prognostic markers. The sequencing of large cohort of pediatric non-DS-AMKL samples led to the discovery of novel genetic aberrations, including high-frequency fusions, such as CBFA2T3-GLIS2 and NUP98-KDM5 A, as well as less frequent aberrations, such as HOX rearrangements. These new insights into the genetic landscape of pediatric non-DS-AMKL has allowed refining the risk-group stratification, leading to important changes in the prognostic scenario of these patients. This review summarizes the most important molecular pathogenic mechanisms of pediatric non-DS-AMKL. A critical discussion on how novel genetic abnormalities have refined the risk profile assessment and changed the management of these patients in clinical practice is also provided.
Collapse
Affiliation(s)
- Riccardo Masetti
- Department of Pediatrics, "Lalla Seràgnoli", Hematology-Oncology Unit, University of Bologna, Bologna, Italy
| | - Vanessa Guidi
- Department of Pediatrics, "Lalla Seràgnoli", Hematology-Oncology Unit, University of Bologna, Bologna, Italy.
| | - Laura Ronchini
- Department of Pediatrics, "Lalla Seràgnoli", Hematology-Oncology Unit, University of Bologna, Bologna, Italy
| | - Nicola Salvatore Bertuccio
- Department of Pediatrics, "Lalla Seràgnoli", Hematology-Oncology Unit, University of Bologna, Bologna, Italy
| | - Franco Locatelli
- Department of Pediatric Hematology-Oncology and Cell and Gene Therapy, IRCCS Ospedale Pediatrico Bambino Gesù, Sapienza University of Rome, Rome, Italy
| | - Andrea Pession
- Department of Pediatrics, "Lalla Seràgnoli", Hematology-Oncology Unit, University of Bologna, Bologna, Italy
| |
Collapse
|
8
|
Vu LP, Cheng Y, Kharas MG. The Biology of m 6A RNA Methylation in Normal and Malignant Hematopoiesis. Cancer Discov 2018; 9:25-33. [PMID: 30578356 DOI: 10.1158/2159-8290.cd-18-0959] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 11/15/2018] [Accepted: 11/16/2018] [Indexed: 11/16/2022]
Abstract
Hematopoietic development and differentiation are highly regulated processes, and recent studies focusing on m6A mRNA methylation have uncovered how this mark controls cell fate in both normal and malignant hematopoietic states. In this review, we focus on how writers, readers, and erasers of RNA methylation can mediate distinct phenotypes on mRNAs and on cells. Targeting the RNA methylation program has emerged as a potential novel therapeutic strategy, and we explore the role for these regulators in both normal and dysregulated cell contexts. SIGNIFICANCE: RNA methylation is required for cancer cell survival in solid tumors and in acute myeloid leukemia, and targeting this pathway has been proposed as a new therapeutic strategy in cancer. However, understanding the role for RNA methylation in both normal and malignant states is essential for understanding the potential consequences for therapeutic intervention.
Collapse
Affiliation(s)
- Ly P Vu
- Molecular Pharmacology Program, Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Yuanming Cheng
- Molecular Pharmacology Program, Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Michael G Kharas
- Molecular Pharmacology Program, Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Memorial Sloan Kettering Cancer Center, New York, New York.
| |
Collapse
|
9
|
Pinello N, Sun S, Wong JJL. Aberrant expression of enzymes regulating m 6A mRNA methylation: implication in cancer. Cancer Biol Med 2018; 15:323-334. [PMID: 30766746 PMCID: PMC6372906 DOI: 10.20892/j.issn.2095-3941.2018.0365] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
N6-methyladenosine (m6A) is an essential RNA modification that regulates key cellular processes, including stem cell renewal, cellular differentiation, and response to DNA damage. Unsurprisingly, aberrant m6A methylation has been implicated in the development and maintenance of diverse human cancers. Altered m6A levels affect RNA processing, mRNA degradation, and translation of mRNAs into proteins, thereby disrupting gene expression regulation and promoting tumorigenesis. Recent studies have reported that the abnormal expression of m6A regulatory enzymes affects m6A abundance and consequently dysregulates the expression of tumor suppressor genes and oncogenes, including MYC, SOCS2, ADAM19, and PTEN. In this review, we discuss the specific roles of m6A "writers", "erasers", and "readers" in normal physiology and how their altered expression promotes tumorigenesis. We also describe the potential of exploiting the aberrant expression of these enzymes for cancer diagnosis, prognosis, and the development of novel therapies.
Collapse
Affiliation(s)
- Natalia Pinello
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia.,Sydney Medical School, The University of Sydney, Camperdown 2050, Australia
| | - Stephanie Sun
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia.,Sydney Medical School, The University of Sydney, Camperdown 2050, Australia
| | - Justin Jong-Leong Wong
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia.,Sydney Medical School, The University of Sydney, Camperdown 2050, Australia
| |
Collapse
|
10
|
Liu T, Zhang Z, Yu C, Zeng C, Xu X, Wu G, Huang Z, Li W. Tetrandrine antagonizes acute megakaryoblastic leukaemia growth by forcing autophagy-mediated differentiation. Br J Pharmacol 2017; 174:4308-4328. [PMID: 28901537 DOI: 10.1111/bph.14031] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 08/27/2017] [Accepted: 08/31/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND PURPOSE The poor prognosis of acute megakaryoblastic leukaemia (AMKL) means there is a need to develop novel therapeutic methods to treat this condition. It was recently shown that inducing megakaryoblasts to undergo terminal differentiation is effective as a treatment for AMKL. This encouraged us to identify a compound that induces megakaryocyte differentiation, which could then act as a potent anti-leukaemia agent. EXPERIMENTAL APPROACH The effects of tetrandrine on the expression of CD41 and cell morphology were investigated in AMKL cells. We used CRISPR/Cas9 knockout system to knock out ATG7 and verify the role of autophagy in tetrandrine-induced megakaryocyte differentiation. shNotch1 and CA-Akt were transfected into K562 cells to examine the downstream pathways of ROS signalling and the mechanistic basis of the tetrandrine-induced megakaryocyte differentiation. The anti-leukaemia effects of tetrandrine were analysed both in vitro and in vivo. KEY RESULTS A low dose of tetrandrine induced cell cycle arrest and megakaryocyte differentiation in AMKL cells via activation of autophagy. Molecularly, we demonstrated that this effect is mediated by activation of Notch1 and Akt and subsequent accumulation of ROS. In contrast, in normal mouse fetal liver cells, although tetrandrine induced autophagy, it did not affect cell proliferation or promote megakaryocyte differentiation, suggesting a specific effect of tetrandrine in malignant megakaryoblasts. Finally, tetrandrine also showed in vivo efficacy in an AMKL xenograft mouse model. CONCLUSIONS AND IMPLICATIONS Modulating autophagy-mediated differentiation may be a novel strategy for treating AMKL, and tetrandrine has the potential to be developed as a differentiation-inducing agent for AMKL chemotherapy.
Collapse
Affiliation(s)
- Ting Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhenxing Zhang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Chunjie Yu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Chang Zeng
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiaoqing Xu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Guixian Wu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zan Huang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Wenhua Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| |
Collapse
|
11
|
GATA factor mutations in hematologic disease. Blood 2017; 129:2103-2110. [PMID: 28179280 DOI: 10.1182/blood-2016-09-687889] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 10/11/2016] [Indexed: 02/06/2023] Open
Abstract
GATA family proteins play essential roles in development of many cell types, including hematopoietic, cardiac, and endodermal lineages. The first three factors, GATAs 1, 2, and 3, are essential for normal hematopoiesis, and their mutations are responsible for a variety of blood disorders. Acquired and inherited GATA1 mutations contribute to Diamond-Blackfan anemia, acute megakaryoblastic leukemia, transient myeloproliferative disorder, and a group of related congenital dyserythropoietic anemias with thrombocytopenia. Conversely, germ line mutations in GATA2 are associated with GATA2 deficiency syndrome, whereas acquired mutations are seen in myelodysplastic syndrome, acute myeloid leukemia, and in blast crisis transformation of chronic myeloid leukemia. The fact that mutations in these genes are commonly seen in blood disorders underscores their critical roles and highlights the need to develop targeted therapies for transcription factors. This review focuses on hematopoietic disorders that are associated with mutations in two prominent GATA family members, GATA1 and GATA2.
Collapse
|
12
|
Recurrent abnormalities can be used for risk group stratification in pediatric AMKL: a retrospective intergroup study. Blood 2016; 127:3424-30. [PMID: 27114462 DOI: 10.1182/blood-2016-01-695551] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 04/14/2016] [Indexed: 12/18/2022] Open
Abstract
Genetic abnormalities and early treatment response are the main prognostic factors in acute myeloid leukemia (AML). Acute megakaryoblastic leukemia (AMKL) is a rare subtype of AML. Deep sequencing has identified CBFA2T3/GLIS2 and NUP98/KDM5A as recurrent aberrations, occurring in similar frequencies as RBM15/MKL1 and KMT2A-rearrangements. We studied whether these cytogenetic aberrations can be used for risk group stratification. To assess frequencies and outcome parameters of recurrent cytogenetic aberrations in AMKL, samples and clinical data of patients treated by the Associazione Italiana Ematologia Oncologia Pediatrica, Berlin-Frankfurt-Munster Study Group, Children's Oncology Group, Dutch Childhood Oncology Group, and the Saint Louis Hôpital were collected, enabling us to screen 153 newly diagnosed pediatric AMKL cases for the aforementioned aberrations and to study their clinical characteristics and outcome. CBFA2T3/GLIS2 was identified in 16% of the cases; RBM15/MKL1, in 12%; NUP98/KDM5A and KMT2A rearrangements, in 9% each; and monosomy 7, in 6%. These aberrations were mutually exclusive. RBM15/MKL1-rearranged patients were significantly younger. No significant differences in sex and white blood cell count were found. NUP98/KDM5A, CBFA2T3/GLIS2, KMT2A-rearranged lesions and monosomy 7 (NCK-7) independently predicted a poor outcome, compared with RBM15/MKL1-rearranged patients and those with AMKL not carrying these molecular lesions. NCK-7-patients (n = 61) showed a 4-year probability of overall survival of 35 ± 6% vs 70 ± 5% in the RBM15/MKL1-other groups (n = 92, P < .0001) and 4-year probability of event-free survival of 33 ± 6% vs 62 ± 5% (P = .0013), the 4-year cumulative incidence of relapse being 42 ± 7% and 19 ± 4% (P = .003), respectively. We conclude that these genetic aberrations may be used for risk group stratification of pediatric AMKL and for treatment tailoring.
Collapse
|
13
|
Yu C, Zeng J, Yan Z, Ma Z, Liu S, Huang Z. Baicalein antagonizes acute megakaryoblastic leukemia in vitro and in vivo by inducing cell cycle arrest. Cell Biosci 2016; 6:20. [PMID: 27042290 PMCID: PMC4818455 DOI: 10.1186/s13578-016-0084-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 02/18/2016] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND The prognosis of acute megakaryoblastic leukemia (AMKL) is really dismal, which urges for development of novel treatment. Baicalein is one type of flavonoids extracted from Scutellaria baicalensis Georgi (Huang Qin). It inhibited cell proliferation and subcutaneous tumor formation of many tumor cell lines. However, whether baicalein possesses anti-AMKL activities has not been tested. RESULTS We found that baicalein potently inhibited proliferation of multiple AMKL cells including CMK, CMY, Y10, 6133, and 6133 MPL/W515L due to apoptosis and cell cycle arrest at G1 phase. Unexpectedly, caspase inhibitor z-VAD-fmk did not restore cell proliferation. In contrast, ectopic expression of Cyclin D1 efficiently antagonized the inhibitory effect of baicalein. In addition, baicalein induced differentiation of 6133 MPL/W515L cells. Finally, baicalein promoted mice survival and reduced disease burden in a mouse model of AMKL. CONCLUSIONS Baicalein possesses potent anti-AMKL activity in vitro and in vivo. Baicalein may be a potent reagent for AMKL therapy.
Collapse
Affiliation(s)
- Chunjie Yu
- College of Life Sciences, Wuhan University, 16 Luo-Jia-Shan Road, Wuhan, 430072 Hubei People's Republic of China
| | - Jiancheng Zeng
- College of Life Sciences, Wuhan University, 16 Luo-Jia-Shan Road, Wuhan, 430072 Hubei People's Republic of China
| | - Zhenzhen Yan
- College of Life Sciences, Wuhan University, 16 Luo-Jia-Shan Road, Wuhan, 430072 Hubei People's Republic of China
| | - Zi Ma
- Department of Chinese Medicine, Zhongnan Hospital of Wuhan University, Wuhan, Hubei People's Republic of China
| | - Shangqin Liu
- Department of Hematology, Zhongnan Hospital of Wuhan University, 169 Donghu Road, Wuhan, 430071 Hubei People's Republic of China
| | - Zan Huang
- College of Life Sciences, Wuhan University, 16 Luo-Jia-Shan Road, Wuhan, 430072 Hubei People's Republic of China
| |
Collapse
|
14
|
Genomic landscape of megakaryopoiesis and platelet function defects. Blood 2016; 127:1249-59. [PMID: 26787733 DOI: 10.1182/blood-2015-07-607952] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 01/05/2016] [Indexed: 12/17/2022] Open
Abstract
Megakaryopoiesis is a complex, stepwise process that takes place largely in the bone marrow. At the apex of the hierarchy, hematopoietic stem cells undergo a number of lineage commitment decisions that ultimately lead to the production of polyploid megakaryocytes. On average, megakaryocytes release 10(11) platelets per day into the blood that repair vascular injuries and prevent excessive bleeding. This differentiation process is tightly controlled by exogenous and endogenous factors, which have been the topics of intense research in the hematopoietic field. Indeed, a skewing of megakaryocyte commitment and differentiation may entail the onset of myeloproliferative neoplasms and other preleukemic disorders together with acute megakaryoblastic leukemia, whereas quantitative or qualitative defects in platelet production can lead to inherited platelet disorders. The recent advent of next-generation sequencing has prompted mapping of the genomic landscape of these conditions to provide an accurate view of the underlying lesions. The aims of this review are to introduce the physiological pathways of megakaryopoiesis and to present landmark studies on acquired and inherited disorders that target them. These studies have not only introduced a new era in the fields of molecular medicine and targeted therapies but may also provide us with a better understanding of the mechanisms underlying normal megakaryopoiesis and thrombopoiesis that can inform efforts to create alternative sources of megakaryocytes and platelets.
Collapse
|
15
|
MN1-Fli1 oncofusion transforms murine hematopoietic progenitor cells into acute megakaryoblastic leukemia cells. Oncogenesis 2015; 4:e179. [PMID: 26690545 PMCID: PMC4688398 DOI: 10.1038/oncsis.2015.41] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Revised: 10/20/2015] [Accepted: 11/09/2015] [Indexed: 11/08/2022] Open
Abstract
Long-term outcome of acute megakaryoblastic leukemia (AMKL) patients without Down's syndrome remains poor. Founding mutations and chimeric oncogenes characterize various AMKL subtypes. However, for around one third of all cases the underlying mechanisms of AMKL leukemogenesis are still largely unknown. Recently, an in-frame fusion of meningeoma 1-friend leukemia virus integration 1 (MN1-Fli1) gene was detected in a child with AMKL. We intended to investigate the potential role of this oncofusion in leukemogenesis of acute myeloid leukemia. Strikingly, expression of MN1-Fli1 in murine hematopoietic progenitor cells was sufficient to induce leukemic transformation generating immature myeloid cells with cytomorphology and expression of surface markers typical for AMKL. Systematic structure function analyses revealed FLS and 3'ETS domains of Fli1 as decisive domains for the AMKL phenotype. Our data highlight an important role of MN1-Fli1 in AMKL leukemogenesis and provide a basis for research assessing the value of this oncofusion as a future diagnostic marker and/or therapeutic target in AMKL patients.
Collapse
|
16
|
Abstract
Pediatric acute myeloid leukemia (AML) represents 15%-20% of all pediatric acute leukemias. Survival rates have increased over the past few decades to ~70%, due to improved supportive care, optimized risk stratification and intensified chemotherapy. In most children, AML presents as a de novo entity, but in a minority, it is a secondary malignancy. The diagnostic classification of pediatric AML includes a combination of morphology, cytochemistry, immunophenotyping and molecular genetics. Outcome is mainly dependent on the initial response to treatment and molecular and cytogenetic aberrations. Treatment consists of a combination of intensive anthracycline- and cytarabine-containing chemotherapy and stem cell transplantation in selected genetic high-risk cases or slow responders. In general, ~30% of all pediatric AML patients will suffer from relapse, whereas 5%-10% of the patients will die due to disease complications or the side-effects of the treatment. Targeted therapy may enhance anti-leukemic efficacy and minimize treatment-related morbidity and mortality, but requires detailed knowledge of the genetic abnormalities and aberrant pathways involved in leukemogenesis. These efforts towards future personalized therapy in a rare disease, such as pediatric AML, require intensive international collaboration in order to enhance the survival rates of pediatric AML, while aiming to reduce long-term toxicity.
Collapse
|
17
|
de Rooij JDE, Zwaan CM, van den Heuvel-Eibrink M. Pediatric AML: From Biology to Clinical Management. J Clin Med 2015; 4:127-49. [PMID: 26237023 PMCID: PMC4470244 DOI: 10.3390/jcm4010127] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 11/28/2014] [Indexed: 12/25/2022] Open
Abstract
Pediatric acute myeloid leukemia (AML) represents 15%–20% of all pediatric acute leukemias. Survival rates have increased over the past few decades to ~70%, due to improved supportive care, optimized risk stratification and intensified chemotherapy. In most children, AML presents as a de novo entity, but in a minority, it is a secondary malignancy. The diagnostic classification of pediatric AML includes a combination of morphology, cytochemistry, immunophenotyping and molecular genetics. Outcome is mainly dependent on the initial response to treatment and molecular and cytogenetic aberrations. Treatment consists of a combination of intensive anthracycline- and cytarabine-containing chemotherapy and stem cell transplantation in selected genetic high-risk cases or slow responders. In general, ~30% of all pediatric AML patients will suffer from relapse, whereas 5%–10% of the patients will die due to disease complications or the side-effects of the treatment. Targeted therapy may enhance anti-leukemic efficacy and minimize treatment-related morbidity and mortality, but requires detailed knowledge of the genetic abnormalities and aberrant pathways involved in leukemogenesis. These efforts towards future personalized therapy in a rare disease, such as pediatric AML, require intensive international collaboration in order to enhance the survival rates of pediatric AML, while aiming to reduce long-term toxicity.
Collapse
Affiliation(s)
- Jasmijn D E de Rooij
- Department of Pediatric Oncology, Erasmus MC-Sophia Children's Hospital, 3015CN Rotterdam, The Netherlands.
| | - C Michel Zwaan
- Department of Pediatric Oncology, Erasmus MC-Sophia Children's Hospital, 3015CN Rotterdam, The Netherlands.
| | | |
Collapse
|
18
|
Kim Y, Schulz VP, Satake N, Gruber TA, Teixeira AM, Halene S, Gallagher PG, Krause DS. Whole-exome sequencing identifies a novel somatic mutation in MMP8 associated with a t(1;22)-acute megakaryoblastic leukemia. Leukemia 2013; 28:945-8. [PMID: 24157583 PMCID: PMC3981934 DOI: 10.1038/leu.2013.314] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Y Kim
- 1] Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT, USA [2] Yale Stem Cell Center, Yale University School of Medicine, New Haven, CT, USA
| | - V P Schulz
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT, USA
| | - N Satake
- Section of Hematology/Oncology, Department of Pediatrics, University of California, Davis, Comprehensive Cancer Center, Sacramento, CA, USA
| | - T A Gruber
- 1] Departments of Oncology, St Jude Children's Research Hospital, Memphis, TN, USA [2] Department of Pathology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - A M Teixeira
- 1] Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT, USA [2] Yale Stem Cell Center, Yale University School of Medicine, New Haven, CT, USA [3] Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - S Halene
- Yale Comprehensive Cancer Center, Division of Hematology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - P G Gallagher
- 1] Department of Pediatrics, Yale University School of Medicine, New Haven, CT, USA [2] Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - D S Krause
- 1] Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT, USA [2] Yale Stem Cell Center, Yale University School of Medicine, New Haven, CT, USA [3] Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| |
Collapse
|
19
|
Thiollier C, Lopez CK, Gerby B, Ignacimouttou C, Poglio S, Duffourd Y, Guégan J, Rivera-Munoz P, Bluteau O, Mabialah V, Diop M, Wen Q, Petit A, Bauchet AL, Reinhardt D, Bornhauser B, Gautheret D, Lecluse Y, Landman-Parker J, Radford I, Vainchenker W, Dastugue N, de Botton S, Dessen P, Bourquin JP, Crispino JD, Ballerini P, Bernard OA, Pflumio F, Mercher T. Characterization of novel genomic alterations and therapeutic approaches using acute megakaryoblastic leukemia xenograft models. ACTA ACUST UNITED AC 2012; 209:2017-31. [PMID: 23045605 PMCID: PMC3478932 DOI: 10.1084/jem.20121343] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Acute megakaryoblastic leukemia (AMKL) is a heterogeneous disease generally associated with poor prognosis. Gene expression profiles indicate the existence of distinct molecular subgroups, and several genetic alterations have been characterized in the past years, including the t(1;22)(p13;q13) and the trisomy 21 associated with GATA1 mutations. However, the majority of patients do not present with known mutations, and the limited access to primary patient leukemic cells impedes the efficient development of novel therapeutic strategies. In this study, using a xenotransplantation approach, we have modeled human pediatric AMKL in immunodeficient mice. Analysis of high-throughput RNA sequencing identified recurrent fusion genes defining new molecular subgroups. One subgroup of patients presented with MLL or NUP98 fusion genes leading to up-regulation of the HOX A cluster genes. A novel CBFA2T3-GLIS2 fusion gene resulting from a cryptic inversion of chromosome 16 was identified in another subgroup of 31% of non-Down syndrome AMKL and strongly associated with a gene expression signature of Hedgehog pathway activation. These molecular data provide useful markers for the diagnosis and follow up of patients. Finally, we show that AMKL xenograft models constitute a relevant in vivo preclinical screening platform to validate the efficacy of novel therapies such as Aurora A kinase inhibitors.
Collapse
Affiliation(s)
- Clarisse Thiollier
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 985, 94805 Villejuif, France
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Hemophagocytosis by leukemic megakaryoblasts in acute myeloid leukemia (megakaryoblastic) with t(1;22)(p13;q13);RBM15-MKL1. J Pediatr Hematol Oncol 2012; 34:576-80. [PMID: 22469944 DOI: 10.1097/mph.0b013e318245a027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Acute megakaryoblastic leukemia is a rare variant of acute myeloid leukemia, whereby leukemic blasts display characteristic morphologic and phenotypic features indicating megakaryocytoid differentiation. A distinct entity characterized by the t(1;22)(p13;q13) translocation, resulting in the RBM15-MKL1 fusion oncogene, has been recently recognized. This is predominantly a disease afflicting infants and displays characteristic clinical features. We present a case of acute megakaryoblastic leukemia with t(1;22)(p13;q13) along with a discussion of the current understanding of the molecular biology of RBM15-MKL1. This case also displayed striking and unusual morphologic appearances including extensive hemophagocytosis by leukemic blasts, which has not been previously reported for this particular type of leukemia.
Collapse
|
21
|
Diagnosis and management of acute myeloid leukemia in children and adolescents: recommendations from an international expert panel. Blood 2012; 120:3187-205. [PMID: 22879540 DOI: 10.1182/blood-2012-03-362608] [Citation(s) in RCA: 376] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Despite major improvements in outcome over the past decades, acute myeloid leukemia (AML) remains a life-threatening malignancy in children, with current survival rates of ∼70%. State-of-the-art recommendations in adult AML have recently been published in this journal by Döhner et al. The primary goal of an international expert panel of the International BFM Study Group AML Committee was to set standards for the management, diagnosis, response assessment, and treatment in childhood AML. This paper aims to discuss differences between childhood and adult AML, and to highlight recommendations that are specific to children. The particular relevance of new diagnostic and prognostic molecular markers in pediatric AML is presented. The general management of pediatric AML, the management of specific pediatric AML cohorts (such as infants) or subtypes of the disease occurring in children (such as Down syndrome related AML), as well as new therapeutic approaches, and the role of supportive care are discussed.
Collapse
|
22
|
MKL1 and MKL2 play redundant and crucial roles in megakaryocyte maturation and platelet formation. Blood 2012; 120:2317-29. [PMID: 22806889 DOI: 10.1182/blood-2012-04-420828] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Serum response factor and its transcriptional cofactor MKL1 are critical for megakaryocyte maturation and platelet formation. We show that MKL2, a homologue of MKL1, is expressed in megakaryocytes and plays a role in megakaryocyte maturation. Using a megakaryocyte-specific Mkl2 knockout (KO) mouse on the conventional Mkl1 KO background to produce double KO (DKO) megakaryocytes and platelets, a critical role for MKL2 is revealed. The decrease in megakaryocyte ploidy and platelet counts of DKO mice is more severe than in Mkl1 KO mice. Platelet dysfunction in DKO mice is revealed by prolonged bleeding times and ineffective platelet activation in vitro in response to adenosine 5'-diphosphate. Electron microscopy and immunofluorescence of DKO megakaryocytes and platelets indicate abnormal cytoskeletal and membrane organization with decreased granule complexity. Surprisingly, the DKO mice have a more extreme thrombocytopenia than mice lacking serum response factor (SRF) expression in the megakaryocyte compartment. Comparison of gene expression reveals approximately 4400 genes whose expression is differentially affected in DKO compared with megakaryocytes deficient in SRF, strongly suggesting that MKL1 and MKL2 have both SRF-dependent and SRF-independent activity in megakaryocytopoiesis.
Collapse
|
23
|
Torres L, Lisboa S, Vieira J, Cerveira N, Santos J, Pinheiro M, Correia C, Bizarro S, Almeida M, Teixeira MR. Acute megakaryoblastic leukemia with a four-way variant translocation originating the RBM15-MKL1 fusion gene. Pediatr Blood Cancer 2011; 56:846-9. [PMID: 21370421 DOI: 10.1002/pbc.22765] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Accepted: 07/01/2010] [Indexed: 11/12/2022]
Abstract
Acute megakaryoblastic leukemia (AMKL) with t(1;22)(p13;q13) is a subset of acute myeloid leukemia (AML) representing <1% of all cases and about 70% of pediatric AMKL in the first year of life. We present a case of a 7-month-old female in whom the bone marrow karyotype showed the derivative chromosome der(22)t(1;22)(p13;q13). The RBM15-MKL1 fusion transcript was detected by RT-PCR and confirmed by sequencing analyses. FISH analyses revealed the presence of the four-way translocation t(1;22;17;18)(p13;q13;q22;q12).
Collapse
Affiliation(s)
- Lurdes Torres
- Department of Genetics, Portuguese Oncology Institute, Porto, Portugal
| | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
von Neuhoff C, Reinhardt D, Sander A, Zimmermann M, Bradtke J, Betts DR, Zemanova Z, Stary J, Bourquin JP, Haas OA, Dworzak MN, Creutzig U. Prognostic Impact of Specific Chromosomal Aberrations in a Large Group of Pediatric Patients With Acute Myeloid Leukemia Treated Uniformly According to Trial AML-BFM 98. J Clin Oncol 2010; 28:2682-9. [DOI: 10.1200/jco.2009.25.6321] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Purpose Because cytogenetic data are essential for risk stratification of childhood acute myeloid leukemia (AML), the impact of chromosomal aberrations is crucial. Patients and Methods Data of a large group of patients younger than 18 years treated according to study AML–Berlin-Frankfurt-Münster (BFM) 98 (n = 454), including their cytogenetics, were analyzed. Results The favorable outcome in the subgroups of patients with t(8;21), inv(16), and t(15;17), with an overall survival of 91% (SE, 4%), 92% (SE, 6%), and 87% (SE, 5%), respectively, was confirmed. Within this group, the 5-year probability of event-free survival (pEFS) of all 17 children with t(8;21) and additional aberrations apart from del(9q) or −X/−Y was 100%. As expected, the cytogenetic finding of a complex karyotype (n = 35; pEFS, 33%; SE, 8%) or a monosomy 7 (n = 12; pEFS, 17%; SE, 11%) was associated with a poor outcome. Compared with remaining patients with cytogenetic data (pEFS, 48%; SE, 2%), prognosis in patients with an MLL rearrangement (n = 91) was inferior (pEFS, 34%; SE, 5%; P = .0005). Particularly, children with t(9;11) and additional aberrations (n = 13; pEFS, 31%; SE, 14%) and MLL rearrangements other than t(9;11) and t(11;19) (n = 41; pEFS, 24%; SE, 7%) had an unfavorable outcome. Nine patients with aberrations in 12p showed an adverse prognosis (pEFS, 11%; SE, 10%). The outcome of patients with aberrations of chromosome 5 (n = 13) was better than expected (pEFS, 50%; SE, 13%). Conclusion Because the prognostic value of rare recurrent chromosomal aberrations still has to be elucidated, these data will contribute to future risk stratification for the treatment of pediatric AML.
Collapse
Affiliation(s)
- Christine von Neuhoff
- From Pediatric Hematology/Oncology, Medical School Hannover, Hannover; Pediatric Haematology/Oncology, Oncogenetic Laboratory, Justus-Liebig-Universität Giessen, Giessen; Children's Hospital, Pediatric Hematology/Oncology, University of Münster, Münster Germany; Our Lady's Children's Hospital, National Centre for Medical Genetics, Crumlin, Dublin, Ireland; Center of Oncocytogenetics, Institute of Clinical Biochemistry and Laboratory Diagnostics, General University Hospital and First Faculty of Medicine,
| | - Dirk Reinhardt
- From Pediatric Hematology/Oncology, Medical School Hannover, Hannover; Pediatric Haematology/Oncology, Oncogenetic Laboratory, Justus-Liebig-Universität Giessen, Giessen; Children's Hospital, Pediatric Hematology/Oncology, University of Münster, Münster Germany; Our Lady's Children's Hospital, National Centre for Medical Genetics, Crumlin, Dublin, Ireland; Center of Oncocytogenetics, Institute of Clinical Biochemistry and Laboratory Diagnostics, General University Hospital and First Faculty of Medicine,
| | - Annette Sander
- From Pediatric Hematology/Oncology, Medical School Hannover, Hannover; Pediatric Haematology/Oncology, Oncogenetic Laboratory, Justus-Liebig-Universität Giessen, Giessen; Children's Hospital, Pediatric Hematology/Oncology, University of Münster, Münster Germany; Our Lady's Children's Hospital, National Centre for Medical Genetics, Crumlin, Dublin, Ireland; Center of Oncocytogenetics, Institute of Clinical Biochemistry and Laboratory Diagnostics, General University Hospital and First Faculty of Medicine,
| | - Martin Zimmermann
- From Pediatric Hematology/Oncology, Medical School Hannover, Hannover; Pediatric Haematology/Oncology, Oncogenetic Laboratory, Justus-Liebig-Universität Giessen, Giessen; Children's Hospital, Pediatric Hematology/Oncology, University of Münster, Münster Germany; Our Lady's Children's Hospital, National Centre for Medical Genetics, Crumlin, Dublin, Ireland; Center of Oncocytogenetics, Institute of Clinical Biochemistry and Laboratory Diagnostics, General University Hospital and First Faculty of Medicine,
| | - Jutta Bradtke
- From Pediatric Hematology/Oncology, Medical School Hannover, Hannover; Pediatric Haematology/Oncology, Oncogenetic Laboratory, Justus-Liebig-Universität Giessen, Giessen; Children's Hospital, Pediatric Hematology/Oncology, University of Münster, Münster Germany; Our Lady's Children's Hospital, National Centre for Medical Genetics, Crumlin, Dublin, Ireland; Center of Oncocytogenetics, Institute of Clinical Biochemistry and Laboratory Diagnostics, General University Hospital and First Faculty of Medicine,
| | - David R. Betts
- From Pediatric Hematology/Oncology, Medical School Hannover, Hannover; Pediatric Haematology/Oncology, Oncogenetic Laboratory, Justus-Liebig-Universität Giessen, Giessen; Children's Hospital, Pediatric Hematology/Oncology, University of Münster, Münster Germany; Our Lady's Children's Hospital, National Centre for Medical Genetics, Crumlin, Dublin, Ireland; Center of Oncocytogenetics, Institute of Clinical Biochemistry and Laboratory Diagnostics, General University Hospital and First Faculty of Medicine,
| | - Zuzana Zemanova
- From Pediatric Hematology/Oncology, Medical School Hannover, Hannover; Pediatric Haematology/Oncology, Oncogenetic Laboratory, Justus-Liebig-Universität Giessen, Giessen; Children's Hospital, Pediatric Hematology/Oncology, University of Münster, Münster Germany; Our Lady's Children's Hospital, National Centre for Medical Genetics, Crumlin, Dublin, Ireland; Center of Oncocytogenetics, Institute of Clinical Biochemistry and Laboratory Diagnostics, General University Hospital and First Faculty of Medicine,
| | - Jan Stary
- From Pediatric Hematology/Oncology, Medical School Hannover, Hannover; Pediatric Haematology/Oncology, Oncogenetic Laboratory, Justus-Liebig-Universität Giessen, Giessen; Children's Hospital, Pediatric Hematology/Oncology, University of Münster, Münster Germany; Our Lady's Children's Hospital, National Centre for Medical Genetics, Crumlin, Dublin, Ireland; Center of Oncocytogenetics, Institute of Clinical Biochemistry and Laboratory Diagnostics, General University Hospital and First Faculty of Medicine,
| | - Jean-Pierre Bourquin
- From Pediatric Hematology/Oncology, Medical School Hannover, Hannover; Pediatric Haematology/Oncology, Oncogenetic Laboratory, Justus-Liebig-Universität Giessen, Giessen; Children's Hospital, Pediatric Hematology/Oncology, University of Münster, Münster Germany; Our Lady's Children's Hospital, National Centre for Medical Genetics, Crumlin, Dublin, Ireland; Center of Oncocytogenetics, Institute of Clinical Biochemistry and Laboratory Diagnostics, General University Hospital and First Faculty of Medicine,
| | - Oskar A. Haas
- From Pediatric Hematology/Oncology, Medical School Hannover, Hannover; Pediatric Haematology/Oncology, Oncogenetic Laboratory, Justus-Liebig-Universität Giessen, Giessen; Children's Hospital, Pediatric Hematology/Oncology, University of Münster, Münster Germany; Our Lady's Children's Hospital, National Centre for Medical Genetics, Crumlin, Dublin, Ireland; Center of Oncocytogenetics, Institute of Clinical Biochemistry and Laboratory Diagnostics, General University Hospital and First Faculty of Medicine,
| | - Michael N. Dworzak
- From Pediatric Hematology/Oncology, Medical School Hannover, Hannover; Pediatric Haematology/Oncology, Oncogenetic Laboratory, Justus-Liebig-Universität Giessen, Giessen; Children's Hospital, Pediatric Hematology/Oncology, University of Münster, Münster Germany; Our Lady's Children's Hospital, National Centre for Medical Genetics, Crumlin, Dublin, Ireland; Center of Oncocytogenetics, Institute of Clinical Biochemistry and Laboratory Diagnostics, General University Hospital and First Faculty of Medicine,
| | - Ursula Creutzig
- From Pediatric Hematology/Oncology, Medical School Hannover, Hannover; Pediatric Haematology/Oncology, Oncogenetic Laboratory, Justus-Liebig-Universität Giessen, Giessen; Children's Hospital, Pediatric Hematology/Oncology, University of Münster, Münster Germany; Our Lady's Children's Hospital, National Centre for Medical Genetics, Crumlin, Dublin, Ireland; Center of Oncocytogenetics, Institute of Clinical Biochemistry and Laboratory Diagnostics, General University Hospital and First Faculty of Medicine,
| |
Collapse
|
25
|
Olson EN, Nordheim A. Linking actin dynamics and gene transcription to drive cellular motile functions. Nat Rev Mol Cell Biol 2010; 11:353-65. [PMID: 20414257 PMCID: PMC3073350 DOI: 10.1038/nrm2890] [Citation(s) in RCA: 785] [Impact Index Per Article: 52.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Numerous physiological and pathological stimuli promote the rearrangement of the actin cytoskeleton, thereby modulating cellular motile functions. Although it seems intuitively obvious that cell motility requires coordinated protein biosynthesis, until recently the linkage between cytoskeletal actin dynamics and correlated gene activities remained unknown. This knowledge gap was filled in part by the discovery that globular actin polymerization liberates myocardin-related transcription factor (MRTF) cofactors, thereby inducing the nuclear transcription factor serum response factor (SRF) to modulate the expression of genes encoding structural and regulatory effectors of actin dynamics. This insight stimulated research to better understand the actin-MRTF-SRF circuit and to identify alternative mechanisms that link cytoskeletal dynamics and genome activity.
Collapse
Affiliation(s)
- Eric N Olson
- Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
| | | |
Collapse
|
26
|
Mercher T, Raffel GD, Moore SA, Cornejo MG, Baudry-Bluteau D, Cagnard N, Jesneck JL, Pikman Y, Cullen D, Williams IR, Akashi K, Shigematsu H, Bourquin JP, Giovannini M, Vainchenker W, Levine RL, Lee BH, Bernard OA, Gilliland DG. The OTT-MAL fusion oncogene activates RBPJ-mediated transcription and induces acute megakaryoblastic leukemia in a knockin mouse model. J Clin Invest 2009; 119:852-64. [PMID: 19287095 DOI: 10.1172/jci35901] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Accepted: 02/04/2009] [Indexed: 12/30/2022] Open
Abstract
Acute megakaryoblastic leukemia (AMKL) is a form of acute myeloid leukemia (AML) associated with a poor prognosis. The genetics and pathophysiology of AMKL are not well understood. We generated a knockin mouse model of the one twenty-two-megakaryocytic acute leukemia (OTT-MAL) fusion oncogene that results from the t(1;22)(p13;q13) translocation specifically associated with a subtype of pediatric AMKL. We report here that OTT-MAL expression deregulated transcriptional activity of the canonical Notch signaling pathway transcription factor recombination signal binding protein for immunoglobulin kappa J region (RBPJ) and caused abnormal fetal megakaryopoiesis. Furthermore, cooperation between OTT-MAL and an activating mutation of the thrombopoietin receptor myeloproliferative leukemia virus oncogene (MPL) efficiently induced a short-latency AMKL that recapitulated all the features of human AMKL, including megakaryoblast hyperproliferation and maturation block, thrombocytopenia, organomegaly, and extensive fibrosis. Our results establish that concomitant activation of RBPJ (Notch signaling) and MPL (cytokine signaling) transforms cells of the megakaryocytic lineage and suggest that specific targeting of these pathways could be of therapeutic value for human AMKL.
Collapse
Affiliation(s)
- Thomas Mercher
- Division of Hematology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Abstract
Oncogenic activation of tyrosine kinase signaling pathway is recurrent in human leukemia. To gain insight into the oncogenic process leading to acute megakaryoblastic leukemia (AMKL), we performed sequence analyses of a subset of oncogenes known to be activated in human myeloid and myeloproliferative disorders. In a series of human AMKL samples from both Down syndrome and non-Down syndrome patients, mutations were identified within KIT, FLT3, JAK2, JAK3, and MPL genes, with a higher frequency in DS than in non-DS patients. The novel mutations were analyzed using BaF3 cells, showing that JAK3 mutations were activating mutations. Finally, we report a novel constitutively active MPL mutant, MPLT487A, observed in a non-Down syndrome childhood AMKL that induces a myeloproliferative disease in mouse bone marrow transplantation assay.
Collapse
|
28
|
OTT-MAL is a deregulated activator of serum response factor-dependent gene expression. Mol Cell Biol 2008; 28:6171-81. [PMID: 18710951 DOI: 10.1128/mcb.00303-08] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The OTT-MAL/RBM15-MKL1 fusion protein is the result of the recurrent translocation t(1;22) in acute megakaryocytic leukemia in infants. How it contributes to the malignancy is unknown. The 3' fusion partner, MAL/MKL1/MRTF-A, is a transcriptional coactivator of serum response factor (SRF). MAL plays a key role in regulated gene expression depending on Rho family GTPases and G-actin. Here we demonstrate that OTT-MAL is a constitutive activator of SRF and target gene expression. This requires the SRF-binding motif and the MAL-derived transactivation domain. OTT-MAL localizes to the nucleus and is not regulated by upstream signaling. OTT-MAL deregulation reflects its independence from control by G-actin, which fails to interact with OTT-MAL in coimmunoprecipitation experiments. Regulation cannot be restored by reintroduction of the entire MAL N terminus into the fusion protein. OTT-MAL also caused a delayed induction of the MAL-independent, ternary complex factor-dependent target genes c-fos and egr-1 and the mitogen-activated protein kinase/Erk pathway. With testing in heterologous tissue culture systems, however, we observed considerable antiproliferative effects of OTT-MAL. Our data suggest that the deregulated activation of MAL-dependent and -independent promoters results in tissue-specific functions of OTT-MAL.
Collapse
|
29
|
Hama A, Yagasaki H, Takahashi Y, Nishio N, Muramatsu H, Yoshida N, Tanaka M, Hidaka H, Watanabe N, Yoshimi A, Matsumoto K, Kudo K, Kato K, Horibe K, Kojima S. Acute megakaryoblastic leukaemia (AMKL) in children: a comparison of AMKL with and without Down syndrome. Br J Haematol 2008; 140:552-61. [PMID: 18275433 DOI: 10.1111/j.1365-2141.2007.06971.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To characterize childhood acute megakaryoblastic leukaemia (AMKL), we reviewed 45 children with AMKL diagnosed between 1986 and 2005 at Nagoya University Hospital and Japanese Red Cross Nagoya First Hospital. Twenty-four patients (53%) had AMKL associated with Down syndrome (DS-AMKL) and 21 (47%) had non-DS-AMKL. The median age of the DS-AMKL patients was 21 months (range, 8-38 months) and that of non-DS-AMKL patients was 15 months (range, 2-185 months). The morphology of blast cells was categorized into three groups according to the stage of megakaryocyte maturation. The blast cells were more immature in DS-AMKL than in non-DS-AMKL in terms of morphology and immunophenotyping. Cytogenetic abnormalities of leukaemic cells were classified into seven categories: normal karyotype including constitutional trisomy 21 in DS-AMKL; numerical abnormalities only; t(1;22)(p13;q13); 3q21q26 abnormalities; t(16;21)(p11;q22); -5/del(5q) and/or -7/del(7q); and other structural changes. The outcome of children with either DS-AMKL or non-DS-AMKL is excellent. The 10-year overall survival estimate was 79% [95% confidence interval (CI): 54-90] for DS-AMKL and 76% (95% CI: 58-91) for non-DS-AMKL (P = 0.81) with a median follow-up of 78 months (range, 20-243 months). Our study shows the diverse heterogeneity of childhood AMKL and the need for subclassification according to cytogenetic and morphological features.
Collapse
Affiliation(s)
- Asahito Hama
- Department of Paediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Novoyatleva T, Heinrich B, Tang Y, Benderska N, Butchbach MER, Lorson CL, Lorson MA, Ben-Dov C, Fehlbaum P, Bracco L, Burghes AHM, Bollen M, Stamm S. Protein phosphatase 1 binds to the RNA recognition motif of several splicing factors and regulates alternative pre-mRNA processing. Hum Mol Genet 2007; 17:52-70. [PMID: 17913700 DOI: 10.1093/hmg/ddm284] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Alternative splicing emerges as one of the most important mechanisms to generate transcript diversity. It is regulated by the formation of protein complexes on pre-mRNA. We demonstrate that protein phosphatase 1 (PP1) binds to the splicing factor transformer2-beta1 (tra2-beta1) via a phylogenetically conserved RVDF sequence located on the RNA recognition motif (RRM) of tra2-beta1. PP1 binds directly to tra2-beta1 and dephosphorylates it, which regulates the interaction between tra2-beta1 and other proteins. Eight other proteins, including SF2/ASF and SRp30c, contain an evolutionary conserved PP1 docking motif in the beta-4 strand of their RRMs indicating that binding to PP1 is a new function of some RRMs. Reducing PP1 activity promotes usage of numerous alternative exons, demonstrating a role of PP1 activity in splice site selection. PP1 inhibition promotes inclusion of the survival of motoneuron 2 exon 7 in a mouse model expressing the human gene. This suggests that reducing PP1 activity could be a new therapeutic principle to treat spinal muscular atrophy and other diseases caused by missplicing events. Our data indicate that the binding of PP1 to evolutionary conserved motifs in several RRMs is the link between known signal transduction pathways regulating PP1 activity and pre-mRNA processing.
Collapse
|
31
|
Ma X, Renda MJ, Wang L, Cheng EC, Niu C, Morris SW, Chi AS, Krause DS. Rbm15 modulates Notch-induced transcriptional activation and affects myeloid differentiation. Mol Cell Biol 2007; 27:3056-64. [PMID: 17283045 PMCID: PMC1899951 DOI: 10.1128/mcb.01339-06] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RBM15 is the fusion partner with MKL in the t(1;22) translocation of acute megakaryoblastic leukemia. To understand the role of the RBM15-MKL1 fusion protein in leukemia, we must understand the normal functions of RBM15 and MKL. Here, we show a role for Rbm15 in myelopoiesis. Rbm15 is expressed at highest levels in hematopoietic stem cells and at more moderate levels during myelopoiesis of murine cell lines and primary murine cells. Decreasing Rbm15 levels with RNA interference enhances differentiation of the 32DWT18 myeloid precursor cell line. Conversely, enforced expression of Rbm15 inhibits 32DWT18 differentiation. We show that Rbm15 alters Notch-induced HES1 promoter activity in a cell type-specific manner. Rbm15 inhibits Notch-induced HES1 transcription in nonhematopoietic cells but stimulates this activity in hematopoietic cell lines, including 32DWT18 and human erythroleukemia cells. Moreover, the N terminus of Rbm15 coimmunoprecipitates with RBPJkappa, a critical factor in Notch signaling, and the Rbm15 N terminus has a dominant negative effect, impairing activation of HES1 promoter activity by full-length-Rbm15. Thus, Rbm15 is differentially expressed during hematopoiesis and may act to inhibit myeloid differentiation in hematopoietic cells via a mechanism that is mediated by stimulation of Notch signaling via RBPJkappa.
Collapse
Affiliation(s)
- Xianyong Ma
- Yale University School of Medicine, Department of Laboratory Medicine, P.O. Box 208035, 333 Cedar Street, New Haven, CT 06520-8035, USA
| | | | | | | | | | | | | | | |
Collapse
|
32
|
Lindtner S, Zolotukhin AS, Uranishi H, Bear J, Kulkarni V, Smulevitch S, Samiotaki M, Panayotou G, Felber BK, Pavlakis GN. RNA-binding Motif Protein 15 Binds to the RNA Transport Element RTE and Provides a Direct Link to the NXF1 Export Pathway. J Biol Chem 2006; 281:36915-28. [PMID: 17001072 DOI: 10.1074/jbc.m608745200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Retroviruses/retroelements provide tools enabling the identification and dissection of basic steps for post-transcriptional regulation of cellular mRNAs. The RNA transport element (RTE) identified in mouse retrotransposons is functionally equivalent to constitutive transport element of Type D retroviruses, yet does not bind directly to the mRNA export receptor NXF1. Here, we report that the RNA-binding motif protein 15 (RBM15) recognizes RTE directly and specifically in vitro and stimulates export and expression of RTE-containing reporter mRNAs in vivo. Tethering of RBM15 to a reporter mRNA showed that RBM15 acts by promoting mRNA export from the nucleus. We also found that RBM15 binds to NXF1 and the two proteins cooperate in stimulating RTE-mediated mRNA export and expression. Thus, RBM15 is a novel mRNA export factor and is part of the NXF1 pathway. We propose that RTE evolved as a high affinity RBM15 ligand to provide a splicing-independent link to NXF1, thereby ensuring efficient nuclear export and expression of retrotransposon transcripts.
Collapse
|
33
|
Sun Y, Boyd K, Xu W, Ma J, Jackson CW, Fu A, Shillingford JM, Robinson GW, Hennighausen L, Hitzler JK, Ma Z, Morris SW. Acute myeloid leukemia-associated Mkl1 (Mrtf-a) is a key regulator of mammary gland function. Mol Cell Biol 2006; 26:5809-26. [PMID: 16847333 PMCID: PMC1592762 DOI: 10.1128/mcb.00024-06] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Transcription of immediate-early genes--as well as multiple genes affecting muscle function, cytoskeletal integrity, apoptosis control, and wound healing/angiogenesis--is regulated by serum response factor (Srf). Extracellular signals regulate Srf in part via a pathway involving megakaryoblastic leukemia 1 (Mkl1, also known as myocardin-related transcription factor A [Mrtf-a]), which coactivates Srf-responsive genes downstream of Rho GTPases. Here we investigate Mkl1 function using gene targeting and show the protein to be essential for the physiologic preparation of the mammary gland during pregnancy and the maintenance of lactation. Lack of Mkl1 causes premature involution and impairs expression of Srf-dependent genes in the mammary myoepithelial cells, which control milk ejection following oxytocin-induced contraction. Despite the importance of Srf in multiple transcriptional pathways and widespread Mkl1 expression, the spectrum of abnormalities associated with Mkl1 absence appears surprisingly restricted.
Collapse
MESH Headings
- Animals
- Animals, Newborn
- Apoptosis
- Child
- Failure to Thrive
- Female
- Gene Expression Profiling
- Gene Expression Regulation
- Gene Targeting
- Heart/anatomy & histology
- Heart/embryology
- Humans
- Infant
- Lactation/physiology
- Leukemia, Megakaryoblastic, Acute
- Male
- Mammary Glands, Animal/abnormalities
- Mammary Glands, Animal/anatomy & histology
- Mammary Glands, Animal/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Milk
- Myocytes, Cardiac/pathology
- Myocytes, Cardiac/ultrastructure
- Oligonucleotide Array Sequence Analysis
- Oxytocin/metabolism
- Pregnancy
- Prolactin/metabolism
- STAT3 Transcription Factor
- Serum Response Factor/genetics
- Serum Response Factor/metabolism
- Trans-Activators/genetics
- Trans-Activators/metabolism
Collapse
Affiliation(s)
- Yi Sun
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Pipes GCT, Creemers EE, Olson EN. The myocardin family of transcriptional coactivators: versatile regulators of cell growth, migration, and myogenesis. Genes Dev 2006; 20:1545-56. [PMID: 16778073 DOI: 10.1101/gad.1428006] [Citation(s) in RCA: 386] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The association of transcriptional coactivators with sequence-specific DNA-binding proteins provides versatility and specificity to gene regulation and expands the regulatory potential of individual cis-regulatory DNA sequences. Members of the myocardin family of coactivators activate genes involved in cell proliferation, migration, and myogenesis by associating with serum response factor (SRF). The partnership of myocardin family members and SRF also controls genes encoding components of the actin cytoskeleton and confers responsiveness to extracellular growth signals and intracellular changes in the cytoskeleton, thereby creating a transcriptional-cytoskeletal regulatory circuit. These functions are reflected in defects in smooth muscle differentiation and function in mice with mutations in myocardin family members. This article reviews the functions and mechanisms of action of the myocardin family of coactivators and the physiological significance of transcriptional coactivation in the context of signal-dependent and cell-type-specific gene regulation.
Collapse
Affiliation(s)
- G C Teg Pipes
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | | | | |
Collapse
|
35
|
Hsiao HH, Yang MY, Liu YC, Hsiao HP, Tseng SB, Chao MC, Liu TC, Lin SF. RBM15-MKL1 (OTT-MAL) fusion transcript in an adult acute myeloid leukemia patient. Am J Hematol 2005; 79:43-5. [PMID: 15849773 DOI: 10.1002/ajh.20298] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The t(1;22)(p13;q13) is a nonrandom chromosomal abnormality in acute leukemia with the fusion oncogene, RBM15-MKL1 (OTT-MAL), identified recently. However, this abnormality has been described only in infants and young children with acute megakaryoblastic leukemia (AMKL). We report a 59-year-old male patient with the diagnosis of acute myeloid leukemia, subtype M1, who harbors an abnormal chromosome +der(1)t(1;22)(p13;q13). The RBM15-MKL1 (OTT-MAL) fusion transcript was also confirmed by the reverse transcriptase-polymerase chain reaction. This unusual abnormality is rare in adult cases of leukemia, and in children it is restricted to AMKL. This report is accompanied by a review of the literature on the t(1;22)(p13;q13).
Collapse
Affiliation(s)
- Hui-Hua Hsiao
- Division of Hematology-Oncology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | | | | | | | | | | | | | | |
Collapse
|
36
|
Chitlur MB, Bhambhani K, Mohamed AN, Ravindranath Y, Savaşan S. Acute megakaryoblastic leukemia with t(17;22)(q21;q13) and liver dysfunction. ACTA ACUST UNITED AC 2004; 154:167-8. [PMID: 15474155 DOI: 10.1016/j.cancergencyto.2004.02.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2003] [Revised: 12/16/2003] [Accepted: 02/18/2004] [Indexed: 11/28/2022]
Abstract
The t(1;22)(p13;q13) is associated with acute megakaryoblastic leukemia (AMKL) seen mostly in young infants and known to have a poor prognosis. A 5-year-old child had prolonged prothrombin and partial thromboplastin times, low albumin, and decreased vitamin K-dependent coagulation factors and factor V activities at the time of AMKL diagnosis. All of these factors normalized following chemotherapy when remission was achieved. Cytogenetic analysis revealed a female karyotype with a balanced t(17;22)(q21;q13). Here, we present an AMKL pediatric case with a novel translocation and significant hepatocellular dysfunction that resolved with chemotherapy. The t(17;22) (q21;q13) may represent a variant of t(1;22)(p13;q13).
Collapse
MESH Headings
- Antineoplastic Combined Chemotherapy Protocols/therapeutic use
- Child, Preschool
- Chromosomes, Human, Pair 17
- Chromosomes, Human, Pair 22
- Female
- Humans
- Karyotyping
- Leukemia, Megakaryoblastic, Acute/drug therapy
- Leukemia, Megakaryoblastic, Acute/genetics
- Liver Diseases/complications
- Translocation, Genetic
Collapse
Affiliation(s)
- Meera B Chitlur
- Children's Hospital of Michigan, Division of Hematology/Oncology, 3901 Beaubien Blvd., Detroit, MI 48201, USA
| | | | | | | | | |
Collapse
|
37
|
Abstract
Abstract
Major strides have been made in our understanding of the molecular basis of adult and pediatric leukemias. More than one hundred disease alleles have been identified and characterized in cell culture and murine models of leukemia. In some instances, molecularly targeted therapies have been developed based on these insights that are currently in clinical trials, such as small molecule inhibitors of FLT3. In addition, it has recently been appreciated that, as with normal hematopoiesis, there is a hierarchical organization among leukemic cells that includes a rare population of leukemic stem cells that have properties of self-renewal. Understanding the characteristics of these leukemic stem cells may provide new insights into leukemia therapies that target self-renewal pathways.
In Section I, Dr. Craig Jordan reviews the data that supports the existence of a “leukemia stem cell.” He provides an overview of the functional properties of leukemic stem cells, their relationship to hematopoietic stem cells, and the relevance of leukemic stem cells in other human malignancies including solid tumors. He briefly discusses what is known of the pathways that regulate properties of self-renewal.
Dr. Gary Gilliland provides an overview of the genetics of adult leukemias in Section II and ongoing genome-wide strategies for discovery of new disease alleles. He describes the clinical and therapeutic implications of these findings and provides examples of bench-to-bedside translation of molecularly targeted therapies for AML, including the use of FLT3 inhibitors.
In Section III, Dr. Carolyn Felix reviews recent advances in our understanding of the genetics and therapy of pediatric leukemias. She provides an overview of leukemias that are common in pediatric malignancies but rarely observed in adults, including the TEL-AML1 (ETV6-RUNX1) fusion associated with pediatric B-cell ALL, the OTT-MAL fusion associated with infant megakaryoblastic leukemia, PTPN11 mutations in juvenile myelomonocytic leukemia, and MLL fusion genes in leukemogenesis, among others.
Collapse
Affiliation(s)
- D Gary Gilliland
- Brigham and Women's Hospital, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | | | | |
Collapse
|
38
|
Abeysinghe SS, Chuzhanova N, Krawczak M, Ball EV, Cooper DN. Translocation and gross deletion breakpoints in human inherited disease and cancer I: Nucleotide composition and recombination-associated motifs. Hum Mutat 2003; 22:229-44. [PMID: 12938088 DOI: 10.1002/humu.10254] [Citation(s) in RCA: 187] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Translocations and gross deletions are important causes of both cancer and inherited disease. Such gene rearrangements are nonrandomly distributed in the human genome as a consequence of selection for growth advantage and/or the inherent potential of some DNA sequences to be frequently involved in breakage and recombination. Using the Gross Rearrangement Breakpoint Database [GRaBD; www.uwcm.ac.uk/uwcm/mg/grabd/grabd.html] (containing 397 germ-line and somatic DNA breakpoint junction sequences derived from 219 different rearrangements underlying human inherited disease and cancer), we have analyzed the sequence context of translocation and deletion breakpoints in a search for general characteristics that might have rendered these sequences prone to rearrangement. The oligonucleotide composition of breakpoint junctions and a set of reference sequences, matched for length and genomic location, were compared with respect to their nucleotide composition. Deletion breakpoints were found to be AT-rich whereas by comparison, translocation breakpoints were GC-rich. Alternating purine-pyrimidine sequences were found to be significantly over-represented in the vicinity of deletion breakpoints while polypyrimidine tracts were over-represented at translocation breakpoints. A number of recombination-associated motifs were found to be over-represented at translocation breakpoints (including DNA polymerase pause sites/frameshift hotspots, immunoglobulin heavy chain class switch sites, heptamer/nonamer V(D)J recombination signal sequences, translin binding sites, and the chi element) but, with the exception of the translin-binding site and immunoglobulin heavy chain class switch sites, none of these motifs were over-represented at deletion breakpoints. Alu sequences were found to span both breakpoints in seven cases of gross deletion that may thus be inferred to have arisen by homologous recombination. Our results are therefore consistent with a role for homologous unequal recombination in deletion mutagenesis and a role for nonhomologous recombination in the generation of translocations.
Collapse
Affiliation(s)
- Shaun S Abeysinghe
- Institute of Medical Genetics, University of Wales College of Medicine, Cardiff, UK
| | | | | | | | | |
Collapse
|
39
|
Nguyen Khac F, Bernard OA. [Chromosomal translocations in human malignant hematopoiesis. Structural and functional consequences]. PATHOLOGIE-BIOLOGIE 2003; 51:382-9. [PMID: 12927896 DOI: 10.1016/s0369-8114(03)00113-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The improvement of molecular biology techniques and human genome mapping and sequencing boosted the molecular analysis of chromosomal abnormalities observed in human hematological malignancies. The characterization of structural abnormalities (translocation, deletion) has proven particularly seminal. A better understanding of the pathology itself and of its generation arose from the identification of the genes involved in the chromosomal translocations of human leukemia. This work summaries some of the present knowledge regarding human leukemogenesis.
Collapse
Affiliation(s)
- F Nguyen Khac
- E210 Inserm, Tour Pasteur, hôpital Necker-Enfants-malades, 149, rue de Sèvres, 75743 Paris 15, France
| | | |
Collapse
|
40
|
Mugneret F, Callier P, Favre-Audry B. [Chromosomal abnormalities in acute myeloid leukaemias]. PATHOLOGIE-BIOLOGIE 2003; 51:314-28. [PMID: 12927889 DOI: 10.1016/s0369-8114(03)00114-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Cytogenetic studies of acute myeloid leukaemias reveal non-random chromosomal abnormalities in 50-70% of karyotypes. Some are correlated with morphological and immunological parameters and constitute a prognostic factor independent of the other factors of risk: favourable for acute leukaemias myeloid with translocations t(8;21), t(15;17) and inversion or translocation of the chromosome 16, inv(16)/t(16;16), poor with deletion of the long arm of chromosome 5 del(5q), rearrangement of the 11q23 region and complex karyotypes. The distribution of the anomalies depends on the age: 11q23 and t(8;21) more frequent for the child, del(5q) and complex anomalies more frequent for the adult. The karyotypes are essential for the diagnosis, the follow-up of the patients and the evaluation of the relapse. It plays a fundamental part in the detection of new genes and their partners implied in the leucemogenese. The knowledge of their function is essential to open new therapeutic ways.
Collapse
Affiliation(s)
- F Mugneret
- Laboratoire de cytogénétique, CHU Le-Bocage, 21034 Dijon, France.
| | | | | |
Collapse
|
41
|
Mercher T, Courtois G, Berger R, Bernard OA. [Molecular basis of the t(1;22)(p13;q13) specific for human acute megakaryoblastic leukemia]. PATHOLOGIE-BIOLOGIE 2003; 51:27-32. [PMID: 12628289 DOI: 10.1016/s0369-8114(02)00354-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The t(1;22)(p13;q13) translocation is specifically associated with infant acute megakaryoblastic leukemia (M7). We have recently characterized the two genes involved in this translocation: OTT (One Two Two) and MAL (Megakaryoblastic Acute Leukemia) respectively located on chromosome 1 and 22. The t(1;22) translocation results in the fusion of these genes in all the cases studied to date. We summarize here present knowledge regarding this translocation.
Collapse
Affiliation(s)
- T Mercher
- Inserm EMI 0210, 27, rue Juliette-Dodu, 75010, Paris, France
| | | | | | | |
Collapse
|