1
|
Steinhart J, Möller P, Kull M, Krönke J, Barth TFE. CDK6 protein expression is associated with disease progression and treatment resistance in multiple myeloma. Hemasphere 2024; 8:e32. [PMID: 38434534 PMCID: PMC10878183 DOI: 10.1002/hem3.32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 11/13/2023] [Indexed: 03/05/2024] Open
Abstract
Multiple myeloma (MM) is a heterogeneous malignancy of plasma cells. Despite improvement in the prognosis of MM patients after the introduction of many new drugs in the past decades, MM remains incurable since most patients become treatment-resistant. Cyclin-dependent kinase 6 (CDK6) is activated in many types of cancer and has been associated with drug resistance in MM. However, its association with disease stage, genetic alterations, and outcome has not been systematically investigated in large cohorts. Here, we analyzed CDK6 expression using immunohistochemistry in 203 formalin-fixed paraffin-embedded samples of 146 patients and four healthy individuals. We found that 61.5% of all MM specimens express CDK6 at various levels. CDK6 expression increased with the progression of disease with a median of 0% of CDK6-positive plasma cells in monoclonal gammopathy of undetermined significance (MGUS) (n = 10) to 30% in newly diagnosed MM (n = 78) and up to 70% in relapsed cases (n = 55). The highest median CDK6 was observed in extramedullary myeloma (n = 12), a highly aggressive manifestation of MM. Longitudinal analyses revealed that CDK6 is significantly increased in lenalidomide-treated patients but not in those who did not receive lenalidomide. Furthermore, we observed that patients who underwent lenalidomide-comprising induction therapy had significantly shorter progression-free survival when their samples were CDK6 positive. These data support that CDK6 protein expression is a marker for aggressive and drug-resistant disease and describes a potential drug target in MM.
Collapse
Affiliation(s)
- Johannes Steinhart
- Department of PathologyUlm University HospitalUlmGermany
- Department of Internal Medicine IIIUlm University HospitalUlmGermany
| | - Peter Möller
- Department of PathologyUlm University HospitalUlmGermany
| | - Miriam Kull
- Department of Internal Medicine IIIUlm University HospitalUlmGermany
| | - Jan Krönke
- Department of Internal Medicine IIIUlm University HospitalUlmGermany
- Department of Hematology, Oncology and Cancer Immunology, Charité ‐ Universitätsmedizin Berlincorporate member of Freie Universität Berlin and Humboldt‐Universität zu BerlinBerlinGermany
- German Cancer Consortium (DKTK) partner site Berlin and German Cancer Research Center (DKFZ)HeidelbergGermany
| | | |
Collapse
|
2
|
Abstract
The details of adult neurogenesis, including environmental triggers, region specificity, and species homology remain an area of intense investigation. Slowing or halting age-related cognitive dysfunction, or restoring neurons lost to disease or injury represent just a fraction of potential therapeutic applications. New neurons can derive from stem cells, pluripotent neural progenitor cells, or non-neuronal glial cells, such as astrocytes. Astrocytes must be epigenetically “reprogrammed” to become neurons, which can occur both naturally in vivo, and via artificial exogenous treatments. While neural progenitor cells are localized to a few neurogenic zones in the adult brain, astrocytes populate almost every brain structure. In this review, we will summarize recent research into neurogenesis that arises from conversion of post-mitotic astrocytes, detail the genetic and epigenetic pathways that regulate this process, and discuss the possible clinical relevance in supplementing stem-cell neurogenic therapies.
Collapse
Affiliation(s)
- Brian B Griffiths
- Department of Anesthesiology, Pain & Perioperative Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Anvee Bhutani
- Department of Anesthesiology, Pain & Perioperative Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Creed M Stary
- Department of Anesthesiology, Pain & Perioperative Medicine, Stanford University School of Medicine, Stanford, CA, USA
| |
Collapse
|
3
|
Krimpenfort P, Snoek M, Lambooij JP, Song JY, van der Weide R, Bhaskaran R, Teunissen H, Adams DJ, de Wit E, Berns A. A natural WNT signaling variant potently synergizes with Cdkn2ab loss in skin carcinogenesis. Nat Commun 2019; 10:1425. [PMID: 30926782 PMCID: PMC6441055 DOI: 10.1038/s41467-019-09321-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 02/13/2019] [Indexed: 12/15/2022] Open
Abstract
Cdkn2ab knockout mice, generated from 129P2 ES cells develop skin carcinomas. Here we show that the incidence of these carcinomas drops gradually in the course of backcrossing to the FVB/N background. Microsatellite analyses indicate that this cancer phenotype is linked to a 20 Mb region of 129P2 chromosome 15 harboring the Wnt7b gene, which is preferentially expressed from the 129P2 allele in skin carcinomas and derived cell lines. ChIPseq analysis shows enrichment of H3K27-Ac, a mark for active enhancers, in the 5' region of the Wnt7b 129P2 gene. The Wnt7b 129P2 allele appears sufficient to cause in vitro transformation of Cdkn2ab-deficient cell lines primarily through CDK6 activation. These results point to a critical role of the Cdkn2ab locus in keeping the oncogenic potential of physiological levels of WNT signaling in check and illustrate that GWAS-based searches for cancer predisposing allelic variants can be enhanced by including defined somatically acquired lesions as an additional input.
Collapse
Affiliation(s)
- Paul Krimpenfort
- Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
- Division of Molecular Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Margriet Snoek
- Division of Molecular Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Jan-Paul Lambooij
- Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
- Division of Molecular Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Ji-Ying Song
- Department of Experimental Animal Pathology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Robin van der Weide
- Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
- Division of Gene Regulation, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Rajith Bhaskaran
- Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
- Division of Molecular Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Hans Teunissen
- Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
- Division of Gene Regulation, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - David J Adams
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK
| | - Elzo de Wit
- Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
- Division of Gene Regulation, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Anton Berns
- Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
- Division of Molecular Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
| |
Collapse
|
4
|
Kollmann K, Briand C, Bellutti F, Schicher N, Blunder S, Zojer M, Hoeller C. The interplay of CDK4 and CDK6 in melanoma. Oncotarget 2019; 10:1346-1359. [PMID: 30858922 PMCID: PMC6402717 DOI: 10.18632/oncotarget.26515] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 12/04/2018] [Indexed: 11/25/2022] Open
Abstract
The cyclin-dependent kinases CDK4 and CDK6 promote progression through the cell cycle, where their functions are considered to be redundant. Recent studies have identified an additional role for CDK6 in the transcriptional regulation of cancer-relevant genes such as VEGF-A and EGR1 in hematopoietic malignancies. We show that the CDK4/6 inhibitor PD0332991 causes a significant decrease in tumor growth in a xenotransplantation mouse model of human melanoma. shRNA knockdown of either CDK4 or CDK6 significantly reduces cell proliferation and impedes their migratory capacity in vitro, which translates into a strong inhibition of tumor growth in xenotransplantation experiments. CDK4/6 inhibition results not only in the pronounced reduction of cell proliferation but also in an impaired tumor angiogenesis. CDK6 knockdown in melanoma cell lines impairs VEGF-A expression and reduces the potential stimulation of endothelial cell growth. The knockdown of CDK4 ends in similar results. The effect is caused by changes of CDK6 localization, less CDK6 is detected on the VEGF-A promoter. Bioinformatic analysis of human melanoma patient data verifies the key role of CDK6 in tumor angiogenesis in melanoma. The results highlight the importance of the delicate balance between CDK4 and CDK6 in regulating the cell cycle and transcription.
Collapse
Affiliation(s)
- Karoline Kollmann
- Institute of Pharmacology and Toxicology, Veterinary University of Vienna, Vienna, Austria
| | - Coralie Briand
- Department of Dermatology, Division of General Dermatology, Medical University Vienna, Vienna, Austria
| | - Florian Bellutti
- Institute of Pharmacology and Toxicology, Veterinary University of Vienna, Vienna, Austria
| | - Nikolaus Schicher
- Department of Dermatology, Division of General Dermatology, Medical University Vienna, Vienna, Austria
| | - Stefan Blunder
- Department of Dermatology, Division of General Dermatology, Medical University Vienna, Vienna, Austria
| | - Markus Zojer
- Institute of Pharmacology and Toxicology, Veterinary University of Vienna, Vienna, Austria
| | - Christoph Hoeller
- Department of Dermatology, Division of General Dermatology, Medical University Vienna, Vienna, Austria
| |
Collapse
|
5
|
Andisheh-Tadbir A, Ashraf MJ, Jeiroodi N. Expression of CDK6 in Oral Squamous Cell Carcinomas. Asian Pac J Cancer Prev 2018; 19:1013-1016. [PMID: 29693970 PMCID: PMC6031802 DOI: 10.22034/apjcp.2018.19.4.1013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Background: CDK6 is the key factor in regulation of the cell cycle and essential for passage into the G1 phase. It
also plays an important role in the development of various tumors. In this cross-sectional study expression of the CDK6
protein in oral squamous cell carcinoma (OSCC) and healthy oral mucosa of controls was assessed to determine relations
with malignant transformation and clinicopathologic factors. Method: A total of 60 samples, 45 from OSCCs and 15
from healthy tissue, underwent immunohistochemistry for CDK6. Nuclear and cytoplasmic staining of keratinocytes
was considered as positive and the percentages of positive cells were calculated. Results: Expression of CDK6 was
detected in 55.6% of OSCC samples (25 cases) and 13.3% of controls (2 cases), the difference being significant. Mean
percentage of CDK6 stained cells was 24.2±29.3 in the OSCC cases and 4.33±2.1 in the control group, again statistically
significant. No relationship was detected between CDK6 expression and clinicopathologic factors. Conclusion:
Overexpression of CDK6 observed in OSCC points to a role for this protein in oral carcinogenesis.
Collapse
Affiliation(s)
- Azadeh Andisheh-Tadbir
- Oral and Dental Disease Research Center, Department of Oral and Maxillofacial Pathology, Faculty of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
| | | | | |
Collapse
|
6
|
Uras IZ, Scheicher RM, Kollmann K, Glösmann M, Prchal-Murphy M, Tigan AS, Fux DA, Altamura S, Neves J, Muckenthaler MU, Bennett KL, Kubicek S, Hinds PW, von Lindern M, Sexl V. Cdk6 contributes to cytoskeletal stability in erythroid cells. Haematologica 2017; 102:995-1005. [PMID: 28255017 PMCID: PMC5451331 DOI: 10.3324/haematol.2016.159947] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 02/22/2017] [Indexed: 12/03/2022] Open
Abstract
Mice lacking Cdk6 kinase activity suffer from mild anemia accompanied by elevated numbers of Ter119+ cells in the bone marrow. The animals show hardly any alterations in erythroid development, indicating that Cdk6 is not required for proliferation and maturation of erythroid cells. There is also no difference in stress erythropoiesis following hemolysis in vivo. However, Cdk6−/− erythrocytes have a shortened lifespan and are more sensitive to mechanical stress in vitro, suggesting differences in cytoskeletal architecture. Erythroblasts contain both Cdk4 and Cdk6, while mature erythrocytes apparently lack Cdk4 and their Cdk6 is partly associated with the cytoskeleton. We used mass spectrometry to show that Cdk6 interacts with a number of proteins involved in cytoskeleton organization. Cdk6−/− erythroblasts show impaired F-actin formation and lower levels of gelsolin, which interacts with Cdk6. We also found that Cdk6 regulates the transcription of a panel of genes involved in actin (de-)polymerization. Cdk6-deficient cells are sensitive to drugs that interfere with the cytoskeleton, suggesting that our findings are relevant to the treatment of patients with anemia – and may be relevant to cancer patients treated with the new generation of CDK6 inhibitors.
Collapse
Affiliation(s)
- Iris Z Uras
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine, Vienna, Austria
| | - Ruth M Scheicher
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine, Vienna, Austria
| | - Karoline Kollmann
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine, Vienna, Austria
| | | | - Michaela Prchal-Murphy
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine, Vienna, Austria
| | - Anca S Tigan
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine, Vienna, Austria
| | - Daniela A Fux
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine, Vienna, Austria
| | - Sandro Altamura
- Department of Pediatric Hematology, Oncology, and Immunology, University of Heidelberg, Germany.,Molecular Medicine Partnership Unit, University of Heidelberg, Germany
| | - Joana Neves
- Department of Pediatric Hematology, Oncology, and Immunology, University of Heidelberg, Germany.,Molecular Medicine Partnership Unit, University of Heidelberg, Germany
| | - Martina U Muckenthaler
- Department of Pediatric Hematology, Oncology, and Immunology, University of Heidelberg, Germany.,Molecular Medicine Partnership Unit, University of Heidelberg, Germany
| | - Keiryn L Bennett
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Stefan Kubicek
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Philip W Hinds
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, and Tufts Cancer Center, Boston, MA, USA
| | | | - Veronika Sexl
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine, Vienna, Austria
| |
Collapse
|
7
|
Niclis JC, Murphy SV, Parkinson DY, Zedan A, Sathananthan AH, Cram DS, Heraud P. Three-dimensional imaging of human stem cells using soft X-ray tomography. J R Soc Interface 2016; 12:20150252. [PMID: 26063819 DOI: 10.1098/rsif.2015.0252] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Three-dimensional imaging of human stem cells using transmission soft X-ray tomography (SXT) is presented for the first time. Major organelle types--nuclei, nucleoli, mitochondria, lysosomes and vesicles--were discriminated at approximately 50 nm spatial resolution without the use of contrast agents, on the basis of measured linear X-ray absorption coefficients and comparison of the size and shape of structures to transmission electron microscopy (TEM) images. In addition, SXT was used to visualize the distribution of a cell surface protein using gold-labelled antibody staining. We present the strengths of SXT, which include excellent spatial resolution (intermediate between that of TEM and light microscopy), the lack of the requirement for fixative or contrast agent that might perturb cellular morphology or produce imaging artefacts, and the ability to produce three-dimensional images of cells without microtome sectioning. Possible applications to studying the differentiation of human stem cells are discussed.
Collapse
Affiliation(s)
- J C Niclis
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria 3800, Australia The Florey Institute of Neuroscience and Mental Health, Melbourne University, Parkville, Victoria 3052, Australia
| | - S V Murphy
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria 3800, Australia Wake Forest Baptist Medical Center, Wake Forest Institute for Regenerative Medicine, Winston-Salem, NC, USA
| | - D Y Parkinson
- Advanced Light Source, Lawrence Berkeley National Laboratory, US Department of Energy, Berkeley, CA, USA
| | - A Zedan
- Advanced Light Source, Lawrence Berkeley National Laboratory, US Department of Energy, Berkeley, CA, USA
| | - A H Sathananthan
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria 3800, Australia
| | - D S Cram
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria 3800, Australia
| | - P Heraud
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria 3800, Australia Centre for Biospectroscopy, School of Chemistry, Monash University, Melbourne, Victoria, Australia
| |
Collapse
|
8
|
Cdk4 and Cdk6 cooperate in counteracting the INK4 family of inhibitors during murine leukemogenesis. Blood 2014; 124:2380-90. [PMID: 25157181 DOI: 10.1182/blood-2014-02-555292] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Cdk4 and Cdk6 are related protein kinases that bind d-type cyclins and regulate cell-cycle progression. Cdk4/6 inhibitors are currently being used in advanced clinical trials and show great promise against many types of tumors. Cdk4 and Cdk6 are inhibited by INK4 proteins, which exert tumor-suppressing functions. To test the significance of this inhibitory mechanism, we generated knock-in mice that express a Cdk6 mutant (Cdk6 R31C) insensitive to INK4-mediated inhibition. Cdk6(R/R) mice display altered development of the hematopoietic system without enhanced tumor susceptibility, either in the presence or absence of p53. Unexpectedly, Cdk6 R31C impairs the potential of hematopoietic progenitors to repopulate upon adoptive transfer or after 5-fluorouracil-induced damage. The defects are overcome by eliminating sensitivity of cells to INK4 inhibitors by introducing the INK4-insensitive Cdk4 R24C allele, and INK4-resistant mice are more susceptible to hematopoietic and endocrine tumors. In BCR-ABL-transformed hematopoietic cells, Cdk6 R31C causes increased binding of p16(INK4a) to wild-type Cdk4, whereas cells harboring Cdk4 R24C and Cdk6 R31C are fully insensitive to INK4 inhibitors, resulting in accelerated disease onset. Our observations reveal that Cdk4 and Cdk6 cooperate in hematopoietic tumor development and suggest a role for Cdk6 in sequestering INK4 proteins away from Cdk4.
Collapse
|
9
|
|
10
|
Kawano T, Zhu M, Troiano N, Horowitz M, Bian J, Gundberg C, Kolodziejczak K, Insogna K. LIM kinase 1 deficient mice have reduced bone mass. Bone 2013; 52:70-82. [PMID: 23017662 PMCID: PMC3688839 DOI: 10.1016/j.bone.2012.09.024] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 09/17/2012] [Accepted: 09/19/2012] [Indexed: 12/27/2022]
Abstract
The cytoskeleton determines cell shape and is involved in cell motility. It also plays a role in differentiation and in modulating specialized cellular functions. LIM kinase 1 (LIMK1) participates in cytoskeletal remodeling by phosphorylating and inactivating the actin-severing protein, cofilin. Severing F-actin to release G-actin monomers is required for actin cytoskeletal remodeling. Although less well established, LIMK1 may also influence the cell cycle and modulate metalloproteinase activity. Since the role of LIMK1 in bone cell biology has not been reported, the skeletal phenotype of LIMK1(-/-) mice was examined. LIMK1(-/-) mice had significantly reduced trabecular bone mass when analyzed by microCT (p<0.01). Histomorphometric analyses demonstrated a 31% reduction in the number of osteoblasts (p=0.0003) and a 23% reduction in osteoid surface (p=0.0005). The number of osteoclasts was no different in control and knock out animals. Consistent with the in vivo findings in osteoblasts, the number of osteoblast colony forming units in LIMK1(-/-) bone marrow was reduced by nearly 50%. Further, osteoblasts isolated from LIMK1(-/-) mice showed significantly reduced rates of mineralization in vitro. Osteoclasts from LIMK1(-/-) mice evidenced more rapid cytoskeletal remodeling in response to treatment with CSF1. In keeping with this latter finding, basal levels of phospho-cofilin were reduced in LIMK1(-/-) osteoclasts. LIMK1(-/-) osteoclasts also resorbed dentine slices to a greater extent in vitro and were more active in a pit assay. These data support the hypothesis that LIMK1 is required for normal osteoblast differentiation. In addition, its absence leads to increased cytoskeletal remodeling and bone resorption in osteoclasts.
Collapse
Affiliation(s)
| | - Meiling Zhu
- Department of Medicine, Yale School of Medicine
| | - Nancy Troiano
- Department of Orthopaedics and Rehabilitation, Yale School of Medicine
| | - Mark Horowitz
- Department of Orthopaedics and Rehabilitation, Yale School of Medicine
| | - Jessica Bian
- Department of Internal Medicine, Yale School of Medicine
| | - Caren Gundberg
- Department of Orthopaedics and Rehabilitation, Yale School of Medicine
| | | | - Karl Insogna
- to whom correspondence and reprint requests should be addressed at, Karl Insogna, M.D. PO Box 208020, Yale School of Medicine, 333 Cedar St. New Haven CT, 06520-8020,
| |
Collapse
|
11
|
Pardis S, Tadbir AA, Ashkavandi ZJ, Najvani AD, Ashraf MJ, Ranjbaran H. Expression of CDK6 in Salivary Gland Tumors. JOURNAL OF MEDICAL SCIENCES 2012. [DOI: 10.3923/jms.2012.193.197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
12
|
Meziane EK, Randle SJ, Nelson DE, Lomonosov M, Laman H. Knockdown of Fbxo7 reveals its regulatory role in proliferation and differentiation of haematopoietic precursor cells. J Cell Sci 2011; 124:2175-86. [PMID: 21652635 DOI: 10.1242/jcs.080465] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Fbxo7 is an unusual F-box protein because most of its interacting proteins are not substrates for ubiquitin-mediated degradation. Fbxo7 directly binds p27 and Cdk6, enhances the level of cyclin D-Cdk6 complexes, and its overexpression causes Cdk6-dependent transformation of immortalised fibroblasts. Here, we test the ability of Fbxo7 to transform haematopoietic pro-B (Ba/F3) cells which, unexpectedly, it was unable to do despite high levels of Cdk6. Instead, reduction of Fbxo7 expression increased proliferation, decreased cell size and shortened G1 phase. Analysis of cell cycle regulators showed that cells had decreased levels of p27, and increased levels of S phase cyclins and Cdk2 activity. Also, Fbxo7 protein levels correlated inversely with those of CD43, suggesting direct regulation of its expression and, therefore, of B cell maturation. Alterations to Cdk6 protein levels did not affect the cell cycle, indicating that Cdk6 is neither rate-limiting nor essential in Ba/F3 cells; however, decreased expression of Cdk6 also enhanced levels of CD43, indicating that expression of CD43 is independent of cell cycle regulation. The physiological effect of reduced levels of Fbxo7 was assessed by creating a transgenic mouse with a LacZ insertion into the Fbxo7 locus. Homozygous Fbxo7(LacZ) mice showed significantly increased pro-B cell and pro-erythroblast populations, consistent with Fbxo7 having an anti-proliferative function and/or a role in promoting maturation of precursor cells.
Collapse
Affiliation(s)
- El Kahina Meziane
- Division of Cellular and Genetic Pathology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB21QP, UK
| | | | | | | | | |
Collapse
|
13
|
Hennessy EJ, Sheedy FJ, Santamaria D, Barbacid M, O'Neill LAJ. Toll-like receptor-4 (TLR4) down-regulates microRNA-107, increasing macrophage adhesion via cyclin-dependent kinase 6. J Biol Chem 2011; 286:25531-9. [PMID: 21628465 DOI: 10.1074/jbc.m111.256206] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Toll-like receptors (TLRs) modulate the expression of multiple microRNAs (miRNAs). Here, we report the down-regulation of miR-107 by TLR4 in multiple cell types. The miR-107 sequence occurs in an intron within the sequence encoding the gene for pantothenate kinase 1α (PanK1α), which is regulated by the transcription factor peroxisome proliferator-activating receptor α (PPAR-α). PanK1α is also decreased in response to lipopolysaccharide (LPS). The effect on both miR-107 and PanK1α is consistent with a decrease in PPAR-α expression. We have found that the putative miR-107 target cyclin-dependent kinase 6 (CDK6) expression is increased by TLR4 as a result of the decrease in miR-107. This effect is required for increased adhesion of macrophages in response to LPS, and CDK6-deficient mice are resistant to the lethal effect of LPS. We have therefore identified a mechanism for LPS signaling which involves a decrease in miR-107 leading to an increase in CDK6.
Collapse
Affiliation(s)
- Elizabeth J Hennessy
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Ireland
| | | | | | | | | |
Collapse
|
14
|
Woods M, Pant R, Mallya SM. Cyclin D1 and cyclin D-dependent kinases enhance oral keratinocyte proliferation but do not block keratinocyte differentiation. Int J Oncol 2011; 37:1471-5. [PMID: 21042715 DOI: 10.3892/ijo_00000799] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Maintenance of oral epithelial homeostasis requires a fine balance between cell proliferation and differentiation. However, the molecular mechanisms that couple these processes, and its deregulation in tumorigenesis are not fully understood. Cyclin D1 and its kinase partners CDK4 and CDK6 play an important role in regulating the G1-S phase of the cell cycle. Deregulation of cyclin D1 is a frequent event in oral squamous cell carcinoma. Here, we examined whether overexpression of cyclin D1, CDK4 and CDK6 can deregulate the link between oral keratinocyte proliferation and differentiation. Our results show that cyclin D1 and its kinase partners CDK4 and CDK6 enhance keratinocyte proliferation, but are not sufficient to block calcium-induced keratinocyte differentiation and suggest that deregulation of these G1-regulatory kinases alone is insufficient to uncouple the link between proliferation and differentiation.
Collapse
Affiliation(s)
- Michael Woods
- School of Dentistry, University of California, Los Angeles, Los Angeles, CA 90095-1668, USA
| | | | | |
Collapse
|
15
|
Raucher D, Moktan S, Massodi I, Bidwell GL. Therapeutic peptides for cancer therapy. Part II - cell cycle inhibitory peptides and apoptosis-inducing peptides. Expert Opin Drug Deliv 2009; 6:1049-64. [PMID: 19743895 DOI: 10.1517/17425240903158909] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Therapeutic peptides have great potential as anticancer agents owing to their ease of rational design and target specificity. However, their utility in vivo is limited by low stability and poor tumor penetration. OBJECTIVE The authors review the development of peptide inhibitors with potential for cancer therapy. Peptides that arrest the cell cycle by mimicking CDK inhibitors or induce apoptosis directly are discussed. METHODS The authors searched Medline for articles concerning the development of therapeutic peptides and their delivery. RESULTS/CONCLUSION Inhibition of cancer cell proliferation directly using peptides that arrest the cell cycle or induce apoptosis is a promising strategy. Peptides can be designed that interact very specifically with cyclins and/or cyclin-dependent kinases and with members of apoptotic cascades. Use of these peptides is not limited by their design, as a rational approach to peptide design is much less challenging than the design of small molecule inhibitors of specific protein-protein interactions. However, the limitations of peptide therapy lie in the poor pharmacokinetic properties of these large, often charged molecules. Therefore, overcoming the drug delivery hurdles could open the door for effective peptide therapy, thus making an entirely new class of molecules useful as anticancer drugs.
Collapse
Affiliation(s)
- Drazen Raucher
- The University of Mississippi Medical Center, Department of Biochemistry, Jackson, 39216, USA.
| | | | | | | |
Collapse
|
16
|
Kohrt DM, Crary JI, Gocheva V, Hinds PW, Grossel MJ. Distinct subcellular distribution of cyclin dependent kinase 6. Cell Cycle 2009; 8:2837-43. [PMID: 19667758 DOI: 10.4161/cc.8.17.9521] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Several studies have recently reported that the cyclin dependent kinase (cdk) 6 oncogene plays a role in differentiation of a variety of cell types. This novel function expands the previously understood function of cdk6 as a regulator of G(1) phase of the cell cycle. The proposed mechanisms of these functions both require nuclear localization. That is, cdk6 phosphorylation of the retinoblastoma protein (pRb) to regulate cell cycle, and the recently proposed transcriptional regulation to block differentiation, are both nuclear functions that predict nuclear localization of the kinase. This report provides a thorough analysis of cdk6 localization and compares the localization of a commonly used mutant cdk6 to the corrected wildtype sequence as recorded in GenBank. The widely shared mutant of cdk6 contains a tyrosine residue at amino acid 224 (instead of an aspartic acid) introducing a potential phosphorylation site to the cdk6 sequence. Results indicate a majority of cdk6 is localized to the cytoplasm with concentrations of cdk6 in the edges of the cytoplasm and in the cytoplasmic extensions of cells. The results of this study may help to better understand the emerging roles of cdk6 in cell cycle control, differentiation and cancer.
Collapse
Affiliation(s)
- Dawn M Kohrt
- Department of Biology, Connecticut College, New London, CT 06371, USA
| | | | | | | | | |
Collapse
|
17
|
Nishi K, Inoue H, Schnier JB, Rice RH. Cyclin D1 downregulation is important for permanent cell cycle exit and initiation of differentiation induced by anchorage-deprivation in human keratinocytes. J Cell Biochem 2009; 106:63-72. [PMID: 19021145 DOI: 10.1002/jcb.21978] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
To understand the relationship between permanent cell cycle exit and differentiation the immortalized keratinocyte cell line, SIK and the squamous cell carcinoma, SCC9 were compared during differentiation induced by anchorage-deprivation. The SIK cells when placed in suspension culture promptly lost almost all ability to reinitiate growth by 2 days concomitantly expressing the differentiation specific proteins, transglutaminase (TGK) and involucrin. These cells rapidly underwent G1 cell cycle arrest with complete disappearance of phosphorylated RB. In contrast SCC9 cells neither showed TGK expression nor increase in involucrin. They decreased their colony-forming ability much more slowly, which coordinated well with a gradual decrease in phosphorylated RB, demonstrating the significant resistance to loss of colony-forming ability and cell cycle exit. In accordance, cyclin D1, a positive regulator of cyclin-dependent kinase (CDK) 4/6 which phosphorylates RB decreased drastically in anchorage deprived SIK but not in SCC9 cells. Endogenous cyclin D1 knockdown in SCC9 cells by siRNA enhanced loss of the colony-forming ability during anchorage-deprivation. Conversely enforced expression of cyclin D1 in SIK cells and in another immortalized keratinocyte cell line, HaCaT, partly prevented loss of their colony-forming abilities. Cyclin D1 overexpression antagonized Keratin 10 expression in suspended HaCaT cells. The result demonstrates the importance of cyclin D1 down regulation for proper initiation of keratinocyte differentiation.
Collapse
Affiliation(s)
- Kayoko Nishi
- Department of Environmental Toxicology, School of Agricultural Sciences, University of California Davis, Davis, California 95616, USA.
| | | | | | | |
Collapse
|
18
|
Nakamura M, Nagai A, Tanaka Y, Sekijima Y, Yamashita K. Polarized hydroxyapatite promotes spread and motility of osteoblastic cells. J Biomed Mater Res A 2009; 92:783-90. [DOI: 10.1002/jbm.a.32404] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|