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Cooke SF, Wright TA, Sin YY, Ling J, Kyurkchieva E, Phanthaphol N, Mcskimming T, Herbert K, Rebus S, Biankin AV, Chang DK, Baillie GS, Blair CM. Disruption of the pro-oncogenic c-RAF-PDE8A complex represents a differentiated approach to treating KRAS-c-RAF dependent PDAC. Sci Rep 2024; 14:8998. [PMID: 38637546 PMCID: PMC11026450 DOI: 10.1038/s41598-024-59451-3] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 04/10/2024] [Indexed: 04/20/2024] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is considered the third leading cause of cancer mortality in the western world, offering advanced stage patients with few viable treatment options. Consequently, there remains an urgent unmet need to develop novel therapeutic strategies that can effectively inhibit pro-oncogenic molecular targets underpinning PDACs pathogenesis and progression. One such target is c-RAF, a downstream effector of RAS that is considered essential for the oncogenic growth and survival of mutant RAS-driven cancers (including KRASMT PDAC). Herein, we demonstrate how a novel cell-penetrating peptide disruptor (DRx-170) of the c-RAF-PDE8A protein-protein interaction (PPI) represents a differentiated approach to exploiting the c-RAF-cAMP/PKA signaling axes and treating KRAS-c-RAF dependent PDAC. Through disrupting the c-RAF-PDE8A protein complex, DRx-170 promotes the inactivation of c-RAF through an allosteric mechanism, dependent upon inactivating PKA phosphorylation. DRx-170 inhibits cell proliferation, adhesion and migration of a KRASMT PDAC cell line (PANC1), independent of ERK1/2 activity. Moreover, combining DRx-170 with afatinib significantly enhances PANC1 growth inhibition in both 2D and 3D cellular models. DRx-170 sensitivity appears to correlate with c-RAF dependency. This proof-of-concept study supports the development of DRx-170 as a novel and differentiated strategy for targeting c-RAF activity in KRAS-c-RAF dependent PDAC.
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Affiliation(s)
- Sean F Cooke
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Thomas A Wright
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Yuan Yan Sin
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Jiayue Ling
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Elka Kyurkchieva
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Nattaporn Phanthaphol
- Siriraj Centre of Research Excellence for Cancer Immunotherapy, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Thomas Mcskimming
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Katharine Herbert
- Wolfson Wohl Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Selma Rebus
- Wolfson Wohl Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Andrew V Biankin
- Wolfson Wohl Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - David K Chang
- Wolfson Wohl Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - George S Baillie
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Connor M Blair
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK.
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Cooke SF, Blair CM. Exploiting c-RAF dependency in RAS mutant cancer: beyond catalytic activity. Expert Rev Anticancer Ther 2024; 24:95-100. [PMID: 38362755 DOI: 10.1080/14737140.2024.2319035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 02/12/2024] [Indexed: 02/17/2024]
Affiliation(s)
- Sean F Cooke
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Connor M Blair
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Brown AD, Vergunst KL, Branch M, Blair CM, Dupré DJ, Baillie GS, Langelaan DN. Structural basis of CBP/p300 recruitment by the microphthalmia-associated transcription factor. Biochim Biophys Acta Mol Cell Res 2023; 1870:119520. [PMID: 37353163 DOI: 10.1016/j.bbamcr.2023.119520] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/19/2023] [Accepted: 06/08/2023] [Indexed: 06/25/2023]
Abstract
The microphthalmia-associated transcription factor (MITF) is a master regulator of the melanocyte cell lineage. Aberrant MITF activity can lead to multiple malignancies including skin cancer, where it modulates the progression and invasiveness of melanoma. MITF-regulated gene expression requires recruitment of the transcriptional co-regulator CBP/p300, but details of this process are not fully defined. In this study, we investigate the structural and functional interaction between the MITF N-terminal transactivation domain (MITFTAD) and CBP/p300. Using pulldown assays and nuclear magnetic resonance spectroscopy we determined that MITFTAD is intrinsically disordered and binds to the TAZ1 and TAZ2 domains of CBP/p300 with moderate affinity. The solution-state structure of the MITFTAD:TAZ2 complex reveals that MITF interacts with a hydrophobic surface of TAZ2, while remaining somewhat dynamic. Peptide array and mutagenesis experiments determined that an acidic motif is integral to the MITFTAD:TAZ2 interaction and is necessary for transcriptional activity of MITF. Peptides that bind to the same surface of TAZ2 as MITFTAD, such as the adenoviral protein E1A, are capable of displacing MITF from TAZ2 and inhibiting transactivation. These findings provide insight into co-activator recruitment by MITF that are fundamental to our understanding of MITF targeted gene regulation and melanoma biology.
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Affiliation(s)
- Alexandra D Brown
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Kathleen L Vergunst
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Makenzie Branch
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Connor M Blair
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom of Great Britain and Northern Ireland
| | - Denis J Dupré
- Department of Pharmacology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - George S Baillie
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom of Great Britain and Northern Ireland
| | - David N Langelaan
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
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Wright TA, Gemmell AO, Tejeda GS, Blair CM, Baillie GS. Cancer: Phosphodiesterase type 4C (PDE4C), the forgotten subfamily as a therapeutic target. Int J Biochem Cell Biol 2023; 162:106453. [PMID: 37499270 DOI: 10.1016/j.biocel.2023.106453] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/13/2023] [Accepted: 07/20/2023] [Indexed: 07/29/2023]
Abstract
Phosphodiesterase type 4 (PDE4) enzymes specifically hydrolyse cAMP in many cell signalling systems that are transduced by hormones and other primary messengers. The physiological function of the four PDE4 subfamilies (A, B, C and D) are numerous and varied due to the differentially localised plethora of isoforms that can be detected in cardiovascular, CNS and immune systems. Of the four subfamilies, least is known about PDE4C probably due to its restricted distribution pattern, scarcity of selective inhibitors and the lack of developed research tools. Here, for the first time, we chart the discovery of PDE4C, describe its regulation and highlight cancers where future development of PDE4C selective small molecules may have potential.
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Affiliation(s)
- Thomas A Wright
- School of Cardiovascular and Metabolic Health, College of Veterinary Medical and Life Science, University of Glasgow, Glasgow, UK
| | - Alistair O Gemmell
- School of Cardiovascular and Metabolic Health, College of Veterinary Medical and Life Science, University of Glasgow, Glasgow, UK
| | - Gonzalo S Tejeda
- School of Cardiovascular and Metabolic Health, College of Veterinary Medical and Life Science, University of Glasgow, Glasgow, UK
| | - Connor M Blair
- School of Cardiovascular and Metabolic Health, College of Veterinary Medical and Life Science, University of Glasgow, Glasgow, UK
| | - George S Baillie
- School of Cardiovascular and Metabolic Health, College of Veterinary Medical and Life Science, University of Glasgow, Glasgow, UK.
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Mahindra A, Tejeda G, Rossi M, Janha O, Herbert I, Morris C, Morgan DC, Beattie W, Montezano AC, Hudson B, Tobin AB, Bhella D, Touyz RM, Jamieson AG, Baillie GS, Blair CM. Peptides derived from the SARS-CoV-2 receptor binding motif bind to ACE2 but do not block ACE2-mediated host cell entry or pro-inflammatory cytokine induction. PLoS One 2021; 16:e0260283. [PMID: 34793553 PMCID: PMC8601423 DOI: 10.1371/journal.pone.0260283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 09/01/2021] [Accepted: 11/05/2021] [Indexed: 11/19/2022] Open
Abstract
SARS-CoV-2 viral attachment and entry into host cells is mediated by a direct interaction between viral spike glycoproteins and membrane bound angiotensin-converting enzyme 2 (ACE2). The receptor binding motif (RBM), located within the S1 subunit of the spike protein, incorporates the majority of known ACE2 contact residues responsible for high affinity binding and associated virulence. Observation of existing crystal structures of the SARS-CoV-2 receptor binding domain (SRBD)-ACE2 interface, combined with peptide array screening, allowed us to define a series of linear native RBM-derived peptides that were selected as potential antiviral decoy sequences with the aim of directly binding ACE2 and attenuating viral cell entry. RBM1 (16mer): S443KVGGNYNYLYRLFRK458, RBM2A (25mer): E484GFNCYFPLQSYGFQPTNGVGYQPY508, RBM2B (20mer): F456NCYFPLQSYGFQPTNGVGY505 and RBM2A-Sc (25mer): NYGLQGSPFGYQETPYPFCNFVQYG. Data from fluorescence polarisation experiments suggested direct binding between RBM peptides and ACE2, with binding affinities ranging from the high nM to low μM range (Kd = 0.207-1.206 μM). However, the RBM peptides demonstrated only modest effects in preventing SRBD internalisation and showed no antiviral activity in a spike protein trimer neutralisation assay. The RBM peptides also failed to suppress S1-protein mediated inflammation in an endogenously expressing ACE2 human cell line. We conclude that linear native RBM-derived peptides are unable to outcompete viral spike protein for binding to ACE2 and therefore represent a suboptimal approach to inhibiting SARS-CoV-2 viral cell entry. These findings reinforce the notion that larger biologics (such as soluble ACE2, 'miniproteins', nanobodies and antibodies) are likely better suited as SARS-CoV-2 cell-entry inhibitors than short-sequence linear peptides.
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Affiliation(s)
- Amit Mahindra
- School of Chemistry, University of Glasgow, Glasgow, United Kingdom
| | - Gonzalo Tejeda
- Institute of Molecular Cell & Systems Biology, School of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Mario Rossi
- Institute of Molecular Cell & Systems Biology, School of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, L’Aquila, Italy
| | - Omar Janha
- Institute of Molecular Cell & Systems Biology, School of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Imogen Herbert
- MRC Centre for Virus Research, University of Glasgow, Glasgow, United Kingdom
| | - Caroline Morris
- School of Chemistry, University of Glasgow, Glasgow, United Kingdom
| | | | - Wendy Beattie
- Institute of Cardiovascular and Medical Sciences, Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Augusto C. Montezano
- Institute of Cardiovascular and Medical Sciences, Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Brian Hudson
- Institute of Molecular Cell & Systems Biology, School of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Andrew B. Tobin
- Institute of Molecular Cell & Systems Biology, School of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - David Bhella
- MRC Centre for Virus Research, University of Glasgow, Glasgow, United Kingdom
| | - Rhian M. Touyz
- Institute of Cardiovascular and Medical Sciences, Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | | | - George S. Baillie
- Institute of Cardiovascular and Medical Sciences, Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Connor M. Blair
- Institute of Cardiovascular and Medical Sciences, Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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Morgan DC, Morris C, Mahindra A, Blair CM, Tejeda G, Herbert I, Turnbull ML, Lieber G, Willett BJ, Logan N, Smith B, Tobin AB, Bhella D, Baillie G, Jamieson AG. Stapled ACE2 peptidomimetics designed to target the SARS-CoV-2 spike protein do not prevent virus internalization. Pept Sci (Hoboken) 2021; 113:e24217. [PMID: 33615115 PMCID: PMC7883042 DOI: 10.1002/pep2.24217] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 12/24/2022]
Abstract
COVID-19 is caused by a novel coronavirus called severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). Virus cell entry is mediated through a protein-protein interaction (PPI) between the SARS-CoV-2 spike protein and angiotensin-converting enzyme 2 (ACE2). A series of stapled peptide ACE2 peptidomimetics based on the ACE2 interaction motif were designed to bind the coronavirus S-protein RBD and inhibit binding to the human ACE2 receptor. The peptidomimetics were assessed for antiviral activity in an array of assays including a neutralization pseudovirus assay, immunofluorescence (IF) assay and in-vitro fluorescence polarization (FP) assay. However, none of the peptidomimetics showed activity in these assays, suggesting that an enhanced binding interface is required to outcompete ACE2 for S-protein RBD binding and prevent virus internalization.
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Affiliation(s)
| | | | | | | | - Gonzalo Tejeda
- Centre for Translational PharmacologyInstitute of Molecular Cell and Systems Biology, Davidson Building, University of GlasgowGlasgowUK
| | - Imogen Herbert
- MRC‐University of Glasgow Centre for Virus ResearchGlasgowUK
| | | | - Gauthier Lieber
- MRC‐University of Glasgow Centre for Virus ResearchGlasgowUK
| | | | - Nicola Logan
- MRC‐University of Glasgow Centre for Virus ResearchGlasgowUK
| | - Brian Smith
- Centre for Translational PharmacologyInstitute of Molecular Cell and Systems Biology, Davidson Building, University of GlasgowGlasgowUK
| | - Andrew B. Tobin
- Centre for Translational PharmacologyInstitute of Molecular Cell and Systems Biology, Davidson Building, University of GlasgowGlasgowUK
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Ling J, Blair CM, Baillie GS. Fibrin Breakdown Assay. Bio Protoc 2020; 10:e3585. [PMID: 33659554 DOI: 10.21769/bioprotoc.3585] [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: 11/24/2019] [Revised: 02/13/2020] [Accepted: 02/24/2020] [Indexed: 11/02/2022] Open
Abstract
Fibrinolysis is an integral part of the matrix remodeling process that contributes to tissue repair. Fibrin clots are broken down during fibrinolysis in a controlled process. Fibrin degradation products (FDPs) have also been shown to have a role in the regulation of cell growth and are implicated in various vascular diseases. This protocol was designed to quantitatively measure the extent of fibrin breakdown and how this can be adapted as a tool to further investigate the pathway involved in fibrinolysis or fibrin degradation products. Until now, we haven't found an alternative method to analysis fibrinolysis.
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Affiliation(s)
- Jiayue Ling
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Connor M Blair
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - George S Baillie
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow G12 8QQ, UK
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Blair CM, Ling J, Baillie GS. Measuring cAMP Specific Phosphodiesterase Activity: A Two-step Radioassay. Bio Protoc 2020; 10:e3581. [PMID: 33659551 DOI: 10.21769/bioprotoc.3581] [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: 11/24/2019] [Revised: 02/18/2020] [Accepted: 02/05/2020] [Indexed: 11/02/2022] Open
Abstract
Cyclic nucleotide degrading phosphodiesterase (PDE) enzymes are crucial to the fine tuning of cAMP signaling responses, playing a pivotal role in regulating the temporal and spatial characteristics of discrete cAMP nanodomains and hence the activity of cAMP-effector proteins. As a consequence of orchestrating cAMP homeostasis, dysfunctional PDE activity plays a central role in disease pathogenesis. This highlights the need for developing methods that can be used to further understand PDE function and assess the effectiveness of potentially novel PDE therapeutics. Here we describe such an approach, where PDE activity is indirectly measured through the direct quantification of radioactively tagged cAMP (pmol/min-1/mg-1). This method provides a highly sensitive tool for investigating PDE functionality.
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Affiliation(s)
- Connor M Blair
- Institute of Cardiovascular and Medical Sciences, School of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Jiayue Ling
- Institute of Cardiovascular and Medical Sciences, School of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - George S Baillie
- Institute of Cardiovascular and Medical Sciences, School of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Blair CM, Walsh NM, Littman BH, Marcoux FW, Baillie GS. Targeting B-Raf inhibitor resistant melanoma with novel cell penetrating peptide disrupters of PDE8A - C-Raf. BMC Cancer 2019; 19:266. [PMID: 30909892 PMCID: PMC6434832 DOI: 10.1186/s12885-019-5489-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 03/19/2019] [Indexed: 11/24/2022] Open
Abstract
Background Recent advances in the treatment of melanoma that involve immunotherapy and B-Raf inhibition have revolutionised cancer care for this disease. However, an un-met clinical need remains in B-Raf inhibitor resistant patients where first-generation B-Raf inhibitors provide only short-term disease control. In these cases, B-Raf inhibition leads to paradoxical activation of the C-Raf – MEK – ERK signalling pathway, followed by metastasis. PDE8A has been shown to directly interact with and modulate the cAMP microdomain in the vicinity of C-Raf. This interaction promotes C-Raf activation by attenuating the PKA-mediated inhibitory phosphorylation of the kinase. Methods We have used a novel cell-penetrating peptide agent (PPL-008) that inhibits the PDE8A – C-Raf complex in a human malignant MM415 melanoma cell line and MM415 melanoma xenograft mouse model to investigate ERK MAP kinase signalling. Results We have demonstrated that the PDE8A – C-Raf complex disruptor PPL-008 increased inhibitory C-Raf-S259 phosphorylation and significantly reduced phospho-ERK signalling. We have also discovered that the ability of PPL-008 to dampen ERK signalling can be used to counter B-Raf inhibitor-driven paradoxical activation of phospho-ERK in MM415 cells treated with PLX4032 (Vemurafenib). PPL-008 treatment also significantly retarded the growth of these cells. When applied to a MM415 melanoma xenograft mouse model, PPL-008C penetrated tumour tissue and significantly reduced phospho-ERK signalling in that domain. Conclusion Our data suggests that the PDE8A-C-Raf complex is a promising therapeutic treatment for B-Raf inhibitor resistant melanoma. Electronic supplementary material The online version of this article (10.1186/s12885-019-5489-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Connor M Blair
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.,Portage Glasgow Limited, Glasgow, UK
| | - Nicola M Walsh
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Bruce H Littman
- Portage Pharmaceuticals Limited, Tortola, British Virgin Islands.,EyGen Inc, Wilmington, DE, USA
| | - Frank W Marcoux
- Portage Glasgow Limited, Glasgow, UK.,Portage Pharmaceuticals Limited, Tortola, British Virgin Islands
| | - George S Baillie
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK. .,Portage Glasgow Limited, Glasgow, UK.
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Blair CM. Oil and Gas Discovery Rates. Science 1987; 238:878-9. [PMID: 17829346 DOI: 10.1126/science.238.4829.878-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Nader S, Kjeld JM, Blair CM, Tooley M, Gordon H, Fraser TR. A study of the effect of bromocriptine on serum oestradiol, prolactin, and follicle stimulating hormone levels in puerperal women. Br J Obstet Gynaecol 1975; 82:750-4. [PMID: 1101945 DOI: 10.1111/j.1471-0528.1975.tb00717.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Nine normal women were examined in the first 11 days of the puerperium. Serum prolactin, oestradiol and follicle simulating hormone (FSH) levels were measured and the FSH response to 100 mug of intravenously administered follicle stimulating hormone/lutenizing hormone-releasing hormone (LH/FSH-RH) was assessed on day 1 post partum in five subjects and on days 4 (two subjects), 6 and 7 post partum in the other four subjects. Bromocriptine therapy was given to six of these women and four to seven days after the start of such therapy, when prolactin levels had fallen to normal non-pregnant levels, these women were retested. Before bromocriptine treatment, the basal FSH levels were unmeasurable in six and low in one other of the nine subjects. After bromocriptine treatment, the basal FSH levels were measurable in four out of six patients and were higher than in the untreated patients (P less than 0-01). The FSH response to LH/FSH-RH was unmeasurable in eight out of nine before treatment, which is less than the response seen in 26 normal men and women (P less than 0-01). There was also no discernible FSH response to LH/FSH-RH after treatment with bromocriptine. Before treatment with bromocriptine, the serum prolactin levels were elevated in all nine women but were within the normal range for non-pregnant women after three days of bromocriptine therapy. Thus postpartum gonadotrophin suppression seemed to depend on high prolactin levels and at least part of the antigonadotrophic action of prolactin seemed to be at pituitary level.
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