1
|
Chadwick W, Maudsley S, Hull W, Havolli E, Boshoff E, Hill MDW, Goetghebeur PJD, Harrison DC, Nizami S, Bedford DC, Coope G, Real K, Thiemermann C, Maycox P, Carlton M, Cole SL. The oDGal Mouse: A Novel, Physiologically Relevant Rodent Model of Sporadic Alzheimer's Disease. Int J Mol Sci 2023; 24:ijms24086953. [PMID: 37108119 PMCID: PMC10138655 DOI: 10.3390/ijms24086953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 03/17/2023] [Accepted: 03/30/2023] [Indexed: 04/29/2023] Open
Abstract
Sporadic Alzheimer's disease (sAD) represents a serious and growing worldwide economic and healthcare burden. Almost 95% of current AD patients are associated with sAD as opposed to patients presenting with well-characterized genetic mutations that lead to AD predisposition, i.e., familial AD (fAD). Presently, the use of transgenic (Tg) animals overexpressing human versions of these causative fAD genes represents the dominant research model for AD therapeutic development. As significant differences in etiology exist between sAD and fAD, it is perhaps more appropriate to develop novel, more sAD-reminiscent experimental models that would expedite the discovery of effective therapies for the majority of AD patients. Here we present the oDGal mouse model, a novel model of sAD that displays a range of AD-like pathologies as well as multiple cognitive deficits reminiscent of AD symptomology. Hippocampal cognitive impairment and pathology were delayed with N-acetyl-cysteine (NaC) treatment, which strongly suggests that reactive oxygen species (ROS) are the drivers of downstream pathologies such as elevated amyloid beta and hyperphosphorylated tau. These features demonstrate a desired pathophenotype that distinguishes our model from current transgenic rodent AD models. A preclinical model that presents a phenotype of non-genetic AD-like pathologies and cognitive deficits would benefit the sAD field, particularly when translating therapeutics from the preclinical to the clinical phase.
Collapse
Affiliation(s)
- Wayne Chadwick
- Takeda Cambridge, 418 Cambridge Science Park, Cambridge CB4 0PZ, UK
| | - Stuart Maudsley
- Receptor Biology Lab, University of Antwerp, 2000 Antwerp, Belgium
| | - William Hull
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Centre for Translational Medicine and Therapeutics, Queen Mary University of London, London E1 4NS, UK
| | - Enes Havolli
- Takeda Cambridge, 418 Cambridge Science Park, Cambridge CB4 0PZ, UK
| | - Eugene Boshoff
- Takeda Cambridge, 418 Cambridge Science Park, Cambridge CB4 0PZ, UK
| | - Mark D W Hill
- Takeda Cambridge, 418 Cambridge Science Park, Cambridge CB4 0PZ, UK
| | | | - David C Harrison
- Takeda Cambridge, 418 Cambridge Science Park, Cambridge CB4 0PZ, UK
| | - Sohaib Nizami
- Takeda Cambridge, 418 Cambridge Science Park, Cambridge CB4 0PZ, UK
| | - David C Bedford
- Takeda Cambridge, 418 Cambridge Science Park, Cambridge CB4 0PZ, UK
| | - Gareth Coope
- Takeda Cambridge, 418 Cambridge Science Park, Cambridge CB4 0PZ, UK
| | - Katia Real
- Takeda Cambridge, 418 Cambridge Science Park, Cambridge CB4 0PZ, UK
| | - Christoph Thiemermann
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Centre for Translational Medicine and Therapeutics, Queen Mary University of London, London E1 4NS, UK
| | - Peter Maycox
- Takeda Cambridge, 418 Cambridge Science Park, Cambridge CB4 0PZ, UK
| | - Mark Carlton
- Takeda Cambridge, 418 Cambridge Science Park, Cambridge CB4 0PZ, UK
| | - Sarah L Cole
- Takeda Cambridge, 418 Cambridge Science Park, Cambridge CB4 0PZ, UK
| |
Collapse
|
2
|
Garner KL, Betin VMS, Pinto V, Graham M, Abgueguen E, Barnes M, Bedford DC, McArdle CA, Coward RJM. Enhanced insulin receptor, but not PI3K, signalling protects podocytes from ER stress. Sci Rep 2018; 8:3902. [PMID: 29500363 PMCID: PMC5834602 DOI: 10.1038/s41598-018-22233-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 02/20/2018] [Indexed: 02/06/2023] Open
Abstract
Disruption of the insulin-PI3K-Akt signalling pathway in kidney podocytes causes endoplasmic reticulum (ER) stress, leading to podocyte apoptosis and proteinuria in diabetic nephropathy. We hypothesised that by improving insulin sensitivity we could protect podocytes from ER stress. Here we use established activating transcription factor 6 (ATF6)- and ER stress element (ERSE)-luciferase assays alongside a novel high throughput imaging-based C/EBP homologous protein (CHOP) assay to examine three models of improved insulin sensitivity. We find that by improving insulin sensitivity at the level of the insulin receptor (IR), either by IR over-expression or by knocking down the negative regulator of IR activity, protein tyrosine-phosphatase 1B (PTP1B), podocytes are protected from ER stress caused by fatty acids or diabetic media containing high glucose, high insulin and inflammatory cytokines TNFα and IL-6. However, contrary to this, knockdown of the negative regulator of PI3K-Akt signalling, phosphatase and tensin homolog deleted from chromosome 10 (PTEN), sensitizes podocytes to ER stress and apoptosis, despite increasing Akt phosphorylation. This indicates that protection from ER stress is conferred through not just the PI3K-Akt pathway, and indeed we find that inhibiting the MEK/ERK signalling pathway rescues PTEN knockdown podocytes from ER stress.
Collapse
Affiliation(s)
- Kathryn L Garner
- Bristol Renal, Bristol Medical School, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, UK
| | - Virginie M S Betin
- Bristol Renal, Bristol Medical School, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, UK
| | - Vanda Pinto
- Bristol Renal, Bristol Medical School, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, UK
| | - Mark Graham
- Bristol Renal, Bristol Medical School, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, UK
| | - Emmanuelle Abgueguen
- Takeda Cambridge Ltd., 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Matt Barnes
- Takeda Cambridge Ltd., 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - David C Bedford
- Takeda Cambridge Ltd., 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Craig A McArdle
- Laboratories for Integrative Neuroscience and Endocrinology, Bristol Medical School, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, UK
| | - Richard J M Coward
- Bristol Renal, Bristol Medical School, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, UK.
| |
Collapse
|
3
|
Zheng F, Kasper LH, Bedford DC, Lerach S, Teubner BJW, Brindle PK. Mutation of the CH1 Domain in the Histone Acetyltransferase CREBBP Results in Autism-Relevant Behaviors in Mice. PLoS One 2016; 11:e0146366. [PMID: 26730956 PMCID: PMC4701386 DOI: 10.1371/journal.pone.0146366] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 12/16/2015] [Indexed: 11/18/2022] Open
Abstract
Autism spectrum disorders (ASDs) are a group of neurodevelopmental afflictions characterized by repetitive behaviors, deficits in social interaction, and impaired communication skills. For most ASD patients, the underlying causes are unknown. Genetic mutations have been identified in about 25 percent of ASD cases, including mutations in epigenetic regulators, suggesting that dysregulated chromatin or DNA function is a critical component of ASD. Mutations in the histone acetyltransferase CREB binding protein (CBP, CREBBP) cause Rubinstein-Taybi Syndrome (RTS), a developmental disorder that includes ASD-like symptoms. Recently, genomic studies involving large numbers of ASD patient families have theoretically modeled CBP and its paralog p300 (EP300) as critical hubs in ASD-associated protein and gene interaction networks, and have identified de novo missense mutations in highly conserved residues of the CBP acetyltransferase and CH1 domains. Here we provide animal model evidence that supports this notion that CBP and its CH1 domain are relevant to autism. We show that mice with a deletion mutation in the CBP CH1 (TAZ1) domain (CBPΔCH1/ΔCH1) have an RTS-like phenotype that includes ASD-relevant repetitive behaviors, hyperactivity, social interaction deficits, motor dysfunction, impaired recognition memory, and abnormal synaptic plasticity. Our results therefore indicate that loss of CBP CH1 domain function contributes to RTS, and possibly ASD, and that this domain plays an essential role in normal motor function, cognition and social behavior. Although the key physiological functions affected by ASD-associated mutation of epigenetic regulators have been enigmatic, our findings are consistent with theoretical models involving CBP and p300 in ASD, and with a causative role for recently described ASD-associated CBP mutations.
Collapse
Affiliation(s)
- Fei Zheng
- Department of Biochemistry, St Jude Children’s Research Hospital, Memphis, TN 38105, United States of America
- * E-mail: (FZ); (PB)
| | - Lawryn H. Kasper
- Department of Biochemistry, St Jude Children’s Research Hospital, Memphis, TN 38105, United States of America
| | - David C. Bedford
- Department of Biochemistry, St Jude Children’s Research Hospital, Memphis, TN 38105, United States of America
| | - Stephanie Lerach
- Department of Biochemistry, St Jude Children’s Research Hospital, Memphis, TN 38105, United States of America
| | - Brett J. W. Teubner
- Department of Developmental Neurobiology, St Jude Children’s Research Hospital, Memphis, TN 38105, United States of America
| | - Paul K. Brindle
- Department of Biochemistry, St Jude Children’s Research Hospital, Memphis, TN 38105, United States of America
- * E-mail: (FZ); (PB)
| |
Collapse
|
4
|
Seth A, Ye J, Yu N, Guez F, Bedford DC, Neale GA, Cordi S, Brindle PK, Lemaigre FP, Kaestner KH, Sosa-Pineda B. Prox1 ablation in hepatic progenitors causes defective hepatocyte specification and increases biliary cell commitment. Development 2014; 141:538-47. [PMID: 24449835 DOI: 10.1242/dev.099481] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The liver has multiple functions that preserve homeostasis. Liver diseases are debilitating, costly and often result in death. Elucidating the developmental mechanisms that establish the liver's architecture or generate the cellular diversity of this organ should help advance the prevention, diagnosis and treatment of hepatic diseases. We previously reported that migration of early hepatic precursors away from the gut epithelium requires the activity of the homeobox gene Prox1. Here, we show that Prox1 is a novel regulator of cell differentiation and morphogenesis during hepatogenesis. Prox1 ablation in bipotent hepatoblasts dramatically reduced the expression of multiple hepatocyte genes and led to very defective hepatocyte morphogenesis. As a result, abnormal epithelial structures expressing hepatocyte and cholangiocyte markers or resembling ectopic bile ducts developed in the Prox1-deficient liver parenchyma. By contrast, excessive commitment of hepatoblasts into cholangiocytes, premature intrahepatic bile duct morphogenesis, and biliary hyperplasia occurred in periportal areas of Prox1-deficient livers. Together, these abnormalities indicate that Prox1 activity is necessary to correctly allocate cell fates in liver precursors. These results increase our understanding of differentiation anomalies in pathological conditions and will contribute to improving stem cell protocols in which differentiation is directed towards hepatocytes and cholangiocytes.
Collapse
Affiliation(s)
- Asha Seth
- Department of Genetics, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Abstract
Protein lysine acetyltransferases (HATs or PATs) acetylate histones and other proteins, and are principally modeled as transcriptional coactivators. CREB binding protein (CBP, CREBBP) and its paralog p300 (EP300) constitute the KAT3 family of HATs in mammals, which has mostly unique sequence identity compared to other HAT families. Although studies in yeast show that many histone mutations cause modest or specific phenotypes, similar studies are impractical in mammals and it remains uncertain if histone acetylation is the primary physiological function for CBP/p300. Nonetheless, CBP and p300 mutations in humans and mice show that these coactivators have important roles in development, physiology, and disease, possibly because CBP and p300 act as network “hubs” with more than 400 described protein interaction partners. Analysis of CBP and p300 mutant mouse fibroblasts reveals CBP/p300 are together chiefly responsible for the global acetylation of histone H3 residues K18 and K27, and contribute to other locus-specific histone acetylation events. CBP/p300 can also be important for transcription, but the recruitment of CBP/p300 and their associated histone acetylation marks do not absolutely correlate with a requirement for gene activation. Rather, it appears that target gene context (e.g. DNA sequence) influences the extent to which CBP and p300 are necessary for transcription.
Collapse
Affiliation(s)
- David C Bedford
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | | |
Collapse
|
6
|
Bedford DC, Kasper LH, Wang R, Chang Y, Green DR, Brindle PK. Disrupting the CH1 domain structure in the acetyltransferases CBP and p300 results in lean mice with increased metabolic control. Cell Metab 2011; 14:219-30. [PMID: 21803292 PMCID: PMC3163393 DOI: 10.1016/j.cmet.2011.06.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 11/30/2010] [Accepted: 06/09/2011] [Indexed: 12/30/2022]
Abstract
Opposing activities of acetyltransferases and deacetylases help regulate energy balance. Mice heterozygous for the acetyltransferase CREB binding protein (CBP) are lean and insulin sensitized, but how CBP regulates energy homeostasis is unclear. In one model, the main CBP interaction with the glucagon-responsive factor CREB is not limiting for liver gluconeogenesis, whereas a second model posits that Ser436 in the CH1 (TAZ1) domain of CBP is required for insulin and the antidiabetic drug metformin to inhibit CREB-mediated liver gluconeogenesis. Here we show that conditional knockout of CBP in liver does not decrease fasting blood glucose or gluconeogenic gene expression, consistent with the first model. However, mice in which the CBP CH1 domain structure is disrupted by deleting residues 342-393 (ΔCH1) are lean and insulin sensitized, as are p300ΔCH1 mutants. CBP(ΔCH1/ΔCH1) mice remain metformin responsive. An intact CH1 domain is thus necessary for normal energy storage, but not for the blood glucose-lowering actions of insulin and metformin.
Collapse
Affiliation(s)
- David C Bedford
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | | | | | | | | | | |
Collapse
|
7
|
Affiliation(s)
- David C. Bedford
- Department of Biochemistry, St Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| |
Collapse
|
8
|
Bedford DC, Kasper LH, Fukuyama T, Brindle PK. Target gene context influences the transcriptional requirement for the KAT3 family of CBP and p300 histone acetyltransferases. Epigenetics 2010; 5:9-15. [PMID: 20110770 DOI: 10.4161/epi.5.1.10449] [Citation(s) in RCA: 216] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
One general principle of gene regulation is that DNA-binding transcription factors modulate transcription by recruiting cofactors that modify histones and chromatin structure. A second implicit principle is that a particular cofactor is necessary at all the target genes where the cofactor is recruited. Increasingly, these principles do not appear to be absolute, as experimentally defined relationships between transcription, cofactors and chromatin modification grow in complexity. The KAT3 histone acetyltransferases CREB binding protein (CBP) and p300 have at least 400 interacting protein partners, thereby acting as hubs in gene regulatory networks. Studies using mutant primary cells indicate that the occurrence of CBP and p300 at any given target gene sometimes correlates with, rather than dictates transcription. This suggests that there are unexpected levels of redundancy between CBP/p300 and other unrelated coactivators, or that CBP/p300 recruitment may sometimes be coincidental. A transcription factor may therefore recruit the same group of coactivators as part of its "toolbox", but it is the characteristics of the individual target gene that determine which coactivation "tools" are required for its transcription.
Collapse
Affiliation(s)
- David C Bedford
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, TN, USA
| | | | | | | |
Collapse
|
9
|
Simmgen M, Knauf C, Lopez M, Choudhury AI, Charalambous M, Cantley J, Bedford DC, Claret M, Iglesias MA, Heffron H, Cani PD, Vidal-Puig A, Burcelin R, Withers DJ. Liver-specific deletion of insulin receptor substrate 2 does not impair hepatic glucose and lipid metabolism in mice. Diabetologia 2006; 49:552-61. [PMID: 16404553 DOI: 10.1007/s00125-005-0084-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2005] [Accepted: 09/25/2005] [Indexed: 10/25/2022]
Abstract
AIMS/HYPOTHESIS Hepatic insulin resistance is thought to be a critical component in the pathogenesis of type 2 diabetes but the role of intrinsic insulin signalling pathways in the regulation of hepatic metabolism remains controversial. Global gene targeting in mice and in vitro studies have suggested that IRS2 mediates the physiological effects of insulin in the liver. Reduced hepatic production of IRS2 is found in many cases of insulin resistance. To investigate the role of IRS2 in regulating liver function in vivo, we generated mice that specifically lack Irs2 in the liver (LivIrs2KO). MATERIALS AND METHODS Hepatic insulin signalling events were examined in LivIrs2KO mice by western blotting. Glucose homeostasis and insulin sensitivity were assessed by glucose tolerance tests and hyperinsulinaemic-euglycaemic clamp studies. The effects of high-fat feeding upon glucose homeostasis were also determined. Liver function tests were performed and expression of key metabolic genes in the liver was determined by RT-PCR. RESULTS Proximal insulin signalling events and forkhead box O1 and A2 function were normal in the liver of LivIrs2KO mice, which displayed minimal abnormalities in glucose and lipid homeostasis, hepatic gene expression and liver function. In addition, hepatic lipid homeostasis and the metabolic response to a high-fat diet did not differ between LivIrs2KO and control mice. CONCLUSIONS/INTERPRETATION Our findings suggest that liver IRS2 signalling, surprisingly, is not required for the long-term maintenance of glucose and lipid homeostasis, and that extra-hepatic IRS2-dependent mechanisms are involved in the regulation of these processes.
Collapse
Affiliation(s)
- M Simmgen
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, University Street, London, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Choudhury AI, Heffron H, Smith MA, Al-Qassab H, Xu AW, Selman C, Simmgen M, Clements M, Claret M, Maccoll G, Bedford DC, Hisadome K, Diakonov I, Moosajee V, Bell JD, Speakman JR, Batterham RL, Barsh GS, Ashford MLJ, Withers DJ. The role of insulin receptor substrate 2 in hypothalamic and beta cell function. J Clin Invest 2005; 115:940-50. [PMID: 15841180 PMCID: PMC1069106 DOI: 10.1172/jci24445] [Citation(s) in RCA: 189] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2005] [Accepted: 02/22/2005] [Indexed: 11/17/2022] Open
Abstract
Insulin receptor substrate 2 (Irs2) plays complex roles in energy homeostasis. We generated mice lacking Irs2 in beta cells and a population of hypothalamic neurons (RIPCreIrs2KO), in all neurons (NesCreIrs2KO), and in proopiomelanocortin neurons (POMCCreIrs2KO) to determine the role of Irs2 in the CNS and beta cell. RIPCreIrs2KO mice displayed impaired glucose tolerance and reduced beta cell mass. Overt diabetes did not ensue, because beta cells escaping Cre-mediated recombination progressively populated islets. RIPCreIrs2KO and NesCreIrs2KO mice displayed hyperphagia, obesity, and increased body length, which suggests altered melanocortin action. POMCCreIrs2KO mice did not display this phenotype. RIPCreIrs2KO and NesCreIrs2KO mice retained leptin sensitivity, which suggests that CNS Irs2 pathways are not required for leptin action. NesCreIrs2KO and POMCCreIrs2KO mice did not display reduced beta cell mass, but NesCreIrs2KO mice displayed mild abnormalities of glucose homeostasis. RIPCre neurons did not express POMC or neuropeptide Y. Insulin and a melanocortin agonist depolarized RIPCre neurons, whereas leptin was ineffective. Insulin hyperpolarized and leptin depolarized POMC neurons. Our findings demonstrate a critical role for IRS2 in beta cell and hypothalamic function and provide insights into the role of RIPCre neurons, a distinct hypothalamic neuronal population, in growth and energy homeostasis.
Collapse
Affiliation(s)
- Agharul I Choudhury
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Fry DW, Bedford DC, Harvey PH, Fritsch A, Keller PR, Wu Z, Dobrusin E, Leopold WR, Fattaey A, Garrett MD. Cell cycle and biochemical effects of PD 0183812. A potent inhibitor of the cyclin D-dependent kinases CDK4 and CDK6. J Biol Chem 2001; 276:16617-23. [PMID: 11278443 DOI: 10.1074/jbc.m008867200] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Progression through the G1 phase of the cell cycle requires phosphorylation of the retinoblastoma gene product (pRb) by the cyclin D-dependent kinases CDK4 and CDK6, whose activity can specifically be blocked by the CDK inhibitor p16(INK4A). Misregulation of the pRb/cyclin D/p16(INK4A) pathway is one of the most common events in human cancer and has lead to the suggestion that inhibition of cyclin D-dependent kinase activity may have therapeutic value as an anticancer treatment. Through screening of a chemical library, we initially identified the [2,3-d]pyridopyrimidines as inhibitors of CDK4. Chemical modification resulted in the identification of PD 0183812 as a potent and highly selective inhibitor of both CDK4 and CDK6 kinase activity, which is competitive with ATP. Flow cytometry experiments showed that of the cell lines tested, only those expressing pRb demonstrated a G1 arrest when treated with PD 0183812. This arrest correlated in terms of incubation time and potency with a loss of pRb phosphorylation and a block in proliferation, which was reversible. These results suggest a potential use of this chemical class of compounds as therapeutic agents in the treatment of tumors with functional pRb, possessing cell cycle aberrations in other members of the pRb/cyclin D/p16(INK4A) pathway.
Collapse
Affiliation(s)
- D W Fry
- Department of Cancer Research, Pfizer Global Research and Development, Ann Arbor Laboratories, Ann Arbor, Michigan 48105, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|