1
|
Abstract
PURPOSE OF REVIEW Enchondroma is a common cartilage benign tumor that develops from dysregulation of chondrocyte terminal differentiation during growth plate development. Here we provide an overview of recent progress in understanding causative mutations for enchondroma, dysregulated signaling and metabolic pathways in enchondroma, and the progression from enchondroma to malignant chondrosarcoma. RECENT FINDINGS Several signaling pathways that regulate chondrocyte differentiation are dysregulated in enchondromas. Somatic mutations in the metabolic enzymes isocitrate dehydrogenase 1 and 2 (IDH1/2) are the most common findings in enchondromas. Mechanisms including metabolic regulation, epigenetic regulation, and altered signaling pathways play a role in enchondroma formation and progression. Multiple pathways regulate growth plate development in a coordinated manner. Deregulation of the process can result in chondrocytes failing to undergo differentiation and the development of enchondroma.
Collapse
Affiliation(s)
- Hongyuan Zhang
- Department of Orthopaedic Surgery, Duke University School of Medicine, Durham, NC, 27710, USA
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Benjamin A Alman
- Department of Orthopaedic Surgery, Duke University School of Medicine, Durham, NC, 27710, USA.
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, 27710, USA.
| |
Collapse
|
2
|
Fischer M, Müller GA. Cell cycle transcription control: DREAM/MuvB and RB-E2F complexes. Crit Rev Biochem Mol Biol 2017; 52:638-662. [PMID: 28799433 DOI: 10.1080/10409238.2017.1360836] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The precise timing of cell cycle gene expression is critical for the control of cell proliferation; de-regulation of this timing promotes the formation of cancer and leads to defects during differentiation and development. Entry into and progression through S phase requires expression of genes coding for proteins that function in DNA replication. Expression of a distinct set of genes is essential to pass through mitosis and cytokinesis. Expression of these groups of cell cycle-dependent genes is regulated by the RB pocket protein family, the E2F transcription factor family, and MuvB complexes together with B-MYB and FOXM1. Distinct combinations of these transcription factors promote the transcription of the two major groups of cell cycle genes that are maximally expressed either in S phase (G1/S) or in mitosis (G2/M). In this review, we discuss recent work that has started to uncover the molecular mechanisms controlling the precisely timed expression of these genes at specific cell cycle phases, as well as the repression of the genes when a cell exits the cell cycle.
Collapse
Affiliation(s)
- Martin Fischer
- a Molecular Oncology, Medical School, University of Leipzig , Leipzig , Germany.,b Department of Medical Oncology , Dana-Farber Cancer Institute , Boston , MA , USA.,c Department of Medicine, Brigham and Women's Hospital , Harvard Medical School , Boston , MA , USA
| | - Gerd A Müller
- a Molecular Oncology, Medical School, University of Leipzig , Leipzig , Germany
| |
Collapse
|
3
|
Liban TJ, Medina EM, Tripathi S, Sengupta S, Henry RW, Buchler NE, Rubin SM. Conservation and divergence of C-terminal domain structure in the retinoblastoma protein family. Proc Natl Acad Sci U S A 2017; 114:4942-4947. [PMID: 28439018 PMCID: PMC5441720 DOI: 10.1073/pnas.1619170114] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The retinoblastoma protein (Rb) and the homologous pocket proteins p107 and p130 negatively regulate cell proliferation by binding and inhibiting members of the E2F transcription factor family. The structural features that distinguish Rb from other pocket proteins have been unclear but are critical for understanding their functional diversity and determining why Rb has unique tumor suppressor activities. We describe here important differences in how the Rb and p107 C-terminal domains (CTDs) associate with the coiled-coil and marked-box domains (CMs) of E2Fs. We find that although CTD-CM binding is conserved across protein families, Rb and p107 CTDs show clear preferences for different E2Fs. A crystal structure of the p107 CTD bound to E2F5 and its dimer partner DP1 reveals the molecular basis for pocket protein-E2F binding specificity and how cyclin-dependent kinases differentially regulate pocket proteins through CTD phosphorylation. Our structural and biochemical data together with phylogenetic analyses of Rb and E2F proteins support the conclusion that Rb evolved specific structural motifs that confer its unique capacity to bind with high affinity those E2Fs that are the most potent activators of the cell cycle.
Collapse
Affiliation(s)
- Tyler J Liban
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064
| | - Edgar M Medina
- Department of Biology, Duke University, Durham, NC 27708
- Center for Genomic and Computational Biology, Duke University, Durham, NC 27708
| | - Sarvind Tripathi
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064
| | - Satyaki Sengupta
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824
| | - R William Henry
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824
| | - Nicolas E Buchler
- Department of Biology, Duke University, Durham, NC 27708
- Center for Genomic and Computational Biology, Duke University, Durham, NC 27708
| | - Seth M Rubin
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064;
| |
Collapse
|
4
|
Cell Death in Chondrocytes, Osteoblasts, and Osteocytes. Int J Mol Sci 2016; 17:ijms17122045. [PMID: 27929439 PMCID: PMC5187845 DOI: 10.3390/ijms17122045] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 11/13/2016] [Accepted: 11/23/2016] [Indexed: 12/04/2022] Open
Abstract
Cell death in skeletal component cells, including chondrocytes, osteoblasts, and osteocytes, plays roles in skeletal development, maintenance, and repair as well as in the pathogenesis of osteoarthritis and osteoporosis. Chondrocyte proliferation, differentiation, and apoptosis are important steps for endochondral ossification. Although the inactivation of P53 and RB is involved in the pathogenesis of osteosarcomas, the deletion of p53 and inactivation of Rb are insufficient to enhance chondrocyte proliferation, indicating the presence of multiple inhibitory mechanisms against sarcomagenesis in chondrocytes. The inflammatory processes induced by mechanical injury and chondrocyte death through the release of danger-associated molecular patterns (DAMPs) are involved in the pathogenesis of posttraumatic osteoarthritis. The overexpression of BCLXL increases bone volume with a normal structure and maintains bone during aging by inhibiting osteoblast apoptosis. p53 inhibits osteoblast proliferation and enhances osteoblast apoptosis, thereby reducing bone formation, but also exerts positive effects on osteoblast differentiation through the Akt–FoxOs pathway. Apoptotic osteocytes release ATP, which induces the receptor activator of nuclear factor κ-B ligand (Rankl) expression and osteoclastogenesis, from pannexin 1 channels. Osteocyte death ultimately results in necrosis; DAMPs are released to the bone surface and promote the production of proinflammatory cytokines, which induce Rankl expression, and osteoclastogenesis is further enhanced.
Collapse
|
5
|
Tsang KY, Tsang SW, Chan D, Cheah KSE. The chondrocytic journey in endochondral bone growth and skeletal dysplasia. ACTA ACUST UNITED AC 2015; 102:52-73. [PMID: 24677723 DOI: 10.1002/bdrc.21060] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 02/23/2014] [Indexed: 12/29/2022]
Abstract
The endochondral bones of the skeleton develop from a cartilage template and grow via a process involving a cascade of chondrocyte differentiation steps culminating in formation of a growth plate and the replacement of cartilage by bone. This process of endochondral ossification, driven by the generation of chondrocytes and their subsequent proliferation, differentiation, and production of extracellular matrix constitute a journey, deviation from which inevitably disrupts bone growth and development, and is the basis of human skeletal dysplasias with a wide range of phenotypic severity, from perinatal lethality to progressively deforming. This highly coordinated journey of chondrocyte specification and fate determination is controlled by a myriad of intrinsic and extrinsic factors. SOX9 is the master transcription factor that, in concert with varying partners along the way, directs the different phases of the journey from mesenchymal condensation, chondrogenesis, differentiation, proliferation, and maturation. Extracellular signals, including bone morphogenetic proteins, wingless-related MMTV integration site (WNT), fibroblast growth factor, Indian hedgehog, and parathyroid hormone-related peptide, are all indispensable for growth plate chondrocytes to align and organize into the appropriate columnar architecture and controls their maturation and transition to hypertrophy. Chondrocyte hypertrophy, marked by dramatic volume increase in phases, is controlled by transcription factors SOX9, Runt-related transcription factor, and FOXA2. Hypertrophic chondrocytes mediate the cartilage to bone transition and concomitantly face a live-or-die situation, a subject of much debate. We review recent insights into the coordination of the phases of the chondrocyte journey, and highlight the need for a systems level understanding of the regulatory networks that will facilitate the development of therapeutic approaches for skeletal dysplasia.
Collapse
Affiliation(s)
- Kwok Yeung Tsang
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | | | | | | |
Collapse
|
6
|
Flowers S, Patel PJ, Gleicher S, Amer K, Himelman E, Goel S, Moran E. p107-Dependent recruitment of SWI/SNF to the alkaline phosphatase promoter during osteoblast differentiation. Bone 2014; 69:47-54. [PMID: 25182511 PMCID: PMC5222550 DOI: 10.1016/j.bone.2014.08.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 08/11/2014] [Accepted: 08/16/2014] [Indexed: 12/28/2022]
Abstract
The retinoblastoma protein family is intimately involved in the regulation of tissue specific gene expression during mesenchymal stem cell differentiation. The role of the following proteins, pRB, p107 and p130, is particularly significant in differentiation to the osteoblast lineage, as human germ-line mutations of RB1 greatly increase susceptibility to osteosarcoma. During differentiation, pRB directly targets certain osteogenic genes for activation, including the alkaline phosphatase-encoding gene Alpl. Chromatin immunoprecipitation (ChIP) assays indicate that Alpl is targeted by p107 in differentiating osteoblasts selectively during activation with the same dynamics as pRB, which suggests that p107 helps promote Alpl activation. Mouse models indicate overlapping roles for pRB and p107 in bone and cartilage formation, but very little is known about direct tissue-specific gene targets of p107, or the consequences of targeting by p107. Here, the roles of p107 and pRB were compared using shRNA-mediated knockdown genetics in an osteoblast progenitor model, MC3T3-E1 cells. The results show that p107 has a distinct role along with pRB in induction of Alpl. Deficiency of p107 does not impede recruitment of transcription factors recognized as pRB co-activation partners at the promoter; however, p107 is required for the efficient recruitment of an activating SWI/SNF chromatin-remodeling complex, an essential event in Alpl induction.
Collapse
Affiliation(s)
- Stephen Flowers
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Parth J Patel
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Stephanie Gleicher
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Kamal Amer
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Eric Himelman
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Shruti Goel
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Elizabeth Moran
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA.
| |
Collapse
|
7
|
|
8
|
Update on Targets and Novel Treatment Options for High-Grade Osteosarcoma and Chondrosarcoma. Hematol Oncol Clin North Am 2013; 27:1021-48. [DOI: 10.1016/j.hoc.2013.07.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|