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Maarten F. Bijlsma - One of the best experts on this subject based on the ideXlab platform.
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Patched-2 functions to limit Patched-1 deficient skin cancer growth
Cellular Oncology, 2018Co-Authors: Veronique L. Veenstra, Ilse Dingjan, Cynthia Waasdorp, Helene Damhofer, Hanneke W. Laarhoven, Jan Paul Medema, Maarten F. BijlsmaAbstract:Purpose Basal cell carcinoma (BCC) is one of the most common skin cancers, and is typically driven by an aberrantly activated Hedgehog (Hh) pathway. The Hh pathway is regulated by interactions between the Patched-1 (Ptch1) and Smoothened (Smo) receptors. Smo is an activating receptor and is subject to inhibition by Ptch1. Following ligand binding to Ptch1, its inhibitory action is relieved and pathway activation occurs. This receptor interaction is pivotal to restraining uncontrolled cellular growth. Both receptors have been found to be frequently mutated in BCCs. PTCH2 is a Ptch1 paralog that exhibits overlapping functions in both normal development and tissue homeostasis. As yet, its contribution to cancer growth is poorly defined. Here we set out to assess how PTCH2 inhibits BCC growth. Methods We used several in vitro readouts for transcriptional and chemotactic Hh signaling in BCC-derived ASZ001 cells, and a novel xenograft model to assess in vivo BCC tumor growth. Gene editing by TALEN was used to untangle the different PTCH2-dependent responses to its ligand sonic hedgehog (Shh). Results We first defined the signaling competence of PTCH2 in Ptch1-deficient ASZ001 cells in vitro, and found that PTCH2 ligand binding drives their migration rather than eliciting a transcriptional response. We found that subsequent targeting of PTCH2 abrogated the chemotaxic effect. Next, we tested the contribution of PTCH2 to in vivo tumor growth using a xenograft model and found that reduced Ptch function results in increased tumor growth, but that selective pressure appatently acts against complete PTCH2 ablation. Conclusions We conclude that like Ptch1, PTCH2 exerts a tumor-suppressive function in BCC cells, and that after targeting of both paralogs, ligand-independent activation of the Hh pathway contributes to tumor growth.
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Patched-2 functions to limit Patched-1 deficient skin cancer growth
Cellular Oncology, 2018Co-Authors: Veronique L. Veenstra, Ilse Dingjan, Cynthia Waasdorp, Helene Damhofer, Hanneke W. Laarhoven, Jan Paul Medema, Maarten F. BijlsmaAbstract:Purpose Basal cell carcinoma (BCC) is one of the most common skin cancers, and is typically driven by an aberrantly activated Hedgehog (Hh) pathway. The Hh pathway is regulated by interactions between the Patched-1 (Ptch1) and Smoothened (Smo) receptors. Smo is an activating receptor and is subject to inhibition by Ptch1. Following ligand binding to Ptch1, its inhibitory action is relieved and pathway activation occurs. This receptor interaction is pivotal to restraining uncontrolled cellular growth. Both receptors have been found to be frequently mutated in BCCs. PTCH2 is a Ptch1 paralog that exhibits overlapping functions in both normal development and tissue homeostasis. As yet, its contribution to cancer growth is poorly defined. Here we set out to assess how PTCH2 inhibits BCC growth.
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PTCH2 mediates the shh response in ptch1 cells
Development, 2014Co-Authors: Astrid C. Alfaro, Maarten F. Bijlsma, Brock Roberts, Lina Kwong, Henk RoelinkAbstract:The Hedgehog (Hh) signaling response is regulated by the interaction of three key components that include the sonic hedgehog (Shh) ligand, its receptor patched 1 (Ptch1) and the pathway activator smoothened (Smo). Under the prevailing model of Shh pathway activation, the binding of Shh to Ptch1 (the key Shh receptor) results in the release of Ptch1-mediated inhibition of Smo, leading to Smo activation and subsequent cell-autonomous activation of the Shh response. Consistent with this model, Ptch1−/− cells show a strong upregulation of the Shh response. Our finding that this response can be inhibited by the Shh-blocking antibody 5E1 indicates that the Shh response in Ptch1–/– cells remains ligand dependent. Furthermore, we find that Shh induces a strong response in Ptch1–/–;Shh–/– cells, and that Ptch1–/– fibroblasts retain their ability to migrate towards Shh, demonstrating that Ptch1–/– cells remain sensitive to Shh. Expression of a dominant-negative Ptch1 mutant in the developing chick neural tube had no effect on Shh-mediated patterning, but expression of a dominant-negative form of patched 2 (PTCH2) caused an activation of the Shh response. This indicates that, at early developmental stages, PTCH2 functions to suppress Shh signaling. We found that Ptch1–/–;PTCH2–/– cells cannot further activate the Shh response, demonstrating that PTCH2 mediates the response to Shh in the absence of Ptch1.
Bernd Schimmelpfennig - One of the best experts on this subject based on the ideXlab platform.
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Ground and excited states of PTCH2+: assessment of the no-pair Douglas–Kroll ab initio model potential method
Physical Chemistry Chemical Physics, 2020Co-Authors: Frank Rakowitz, Christel M Marian, Bernd SchimmelpfennigAbstract:Relativistic all-electron and ab initio model potential (AIMP) calculations have been performed on the PTCH2+ ground and low-lying excited states employing a one-component Hamiltonian. Electron correlation is taken into account by means of a multireference configuration interaction treatment whereas spin–orbit coupling effects have been added as a perturbation. The no-pair Douglas–Kroll ab initio model potential method is found to reproduce all-electron results excellently. The one-center spin–orbit mean-field Douglas–Kroll ab initio model potential approach appears to be a competitive means for electronic structure calculations on compounds containing heavy elements. An analysis of the PTCH2+ electronic ground state structure reveals that both the Pt+ configurations d9 and d8s1 participate in the double bond. This finding differs to some extent from a model postulating that a d8s1 structure is preferred.
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ground and excited states of PTCH2 assessment of the no pair douglas kroll ab initio model potential method
Physical Chemistry Chemical Physics, 2000Co-Authors: Frank Rakowitz, Christel M Marian, Bernd SchimmelpfennigAbstract:Relativistic all-electron and ab initio model potential (AIMP) calculations have been performed on the PTCH2+ ground and low-lying excited states employing a one-component Hamiltonian. Electron correlation is taken into account by means of a multireference configuration interaction treatment whereas spin–orbit coupling effects have been added as a perturbation. The no-pair Douglas–Kroll ab initio model potential method is found to reproduce all-electron results excellently. The one-center spin–orbit mean-field Douglas–Kroll ab initio model potential approach appears to be a competitive means for electronic structure calculations on compounds containing heavy elements. An analysis of the PTCH2+ electronic ground state structure reveals that both the Pt+ configurations d9 and d8s1 participate in the double bond. This finding differs to some extent from a model postulating that a d8s1 structure is preferred.
Frank Rakowitz - One of the best experts on this subject based on the ideXlab platform.
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Ground and excited states of PTCH2+: assessment of the no-pair Douglas–Kroll ab initio model potential method
Physical Chemistry Chemical Physics, 2020Co-Authors: Frank Rakowitz, Christel M Marian, Bernd SchimmelpfennigAbstract:Relativistic all-electron and ab initio model potential (AIMP) calculations have been performed on the PTCH2+ ground and low-lying excited states employing a one-component Hamiltonian. Electron correlation is taken into account by means of a multireference configuration interaction treatment whereas spin–orbit coupling effects have been added as a perturbation. The no-pair Douglas–Kroll ab initio model potential method is found to reproduce all-electron results excellently. The one-center spin–orbit mean-field Douglas–Kroll ab initio model potential approach appears to be a competitive means for electronic structure calculations on compounds containing heavy elements. An analysis of the PTCH2+ electronic ground state structure reveals that both the Pt+ configurations d9 and d8s1 participate in the double bond. This finding differs to some extent from a model postulating that a d8s1 structure is preferred.
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ground and excited states of PTCH2 assessment of the no pair douglas kroll ab initio model potential method
Physical Chemistry Chemical Physics, 2000Co-Authors: Frank Rakowitz, Christel M Marian, Bernd SchimmelpfennigAbstract:Relativistic all-electron and ab initio model potential (AIMP) calculations have been performed on the PTCH2+ ground and low-lying excited states employing a one-component Hamiltonian. Electron correlation is taken into account by means of a multireference configuration interaction treatment whereas spin–orbit coupling effects have been added as a perturbation. The no-pair Douglas–Kroll ab initio model potential method is found to reproduce all-electron results excellently. The one-center spin–orbit mean-field Douglas–Kroll ab initio model potential approach appears to be a competitive means for electronic structure calculations on compounds containing heavy elements. An analysis of the PTCH2+ electronic ground state structure reveals that both the Pt+ configurations d9 and d8s1 participate in the double bond. This finding differs to some extent from a model postulating that a d8s1 structure is preferred.
Brandon J. Wainwright - One of the best experts on this subject based on the ideXlab platform.
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Activated Hedgehog-GLI Signaling Causes Congenital Ureteropelvic Junction Obstruction
Journal of The American Society of Nephrology, 2017Co-Authors: Sepideh Sheybani-deloui, Brandon J. Wainwright, Marian V. Staite, Jason E. Cain, Brian J. Nieman, R. Mark Henkelman, S. Steven Potter, Darius J. Bägli, Armando J. LorenzoAbstract:Intrinsic ureteropelvic junction obstruction is the most common cause of congenital hydronephrosis, yet the underlying pathogenesis is undefined. Hedgehog proteins control morphogenesis by promoting GLI-dependent transcriptional activation and inhibiting the formation of the GLI3 transcriptional repressor. Hedgehog regulates differentiation and proliferation of ureteric smooth muscle progenitor cells during murine kidney-ureter development. Histopathologic findings of smooth muscle cell hypertrophy and stroma-like cells, consistently observed in obstructing tissue at the time of surgical correction, suggest that Hedgehog signaling is abnormally regulated during the genesis of congenital intrinsic ureteropelvic junction obstruction. Here, we demonstrate that constitutively active Hedgehog signaling in murine intermediate mesoderm-derived renal progenitors results in hydronephrosis and failure to develop a patent pelvic-ureteric junction. Tissue obstructing the ureteropelvic junction was marked as early as E13.5 by an ectopic population of cells expressing PTCH2, a Hedgehog signaling target. Constitutive expression of GLI3 repressor in Ptch1-deficient mice rescued ectopic PTCH2 expression and obstructive hydronephrosis. Whole transcriptome analysis of isolated PTCH2(+) cells revealed coexpression of genes characteristic of stromal progenitor cells. Genetic lineage tracing indicated that stromal cells blocking the ureteropelvic junction were derived from intermediate mesoderm-derived renal progenitors and were distinct from the smooth muscle or epithelial lineages. Analysis of obstructive ureteric tissue resected from children with congenital intrinsic ureteropelvic junction obstruction revealed a molecular signature similar to that observed in Ptch1-deficient mice. Together, these results demonstrate a Hedgehog-dependent mechanism underlying mammalian intrinsic ureteropelvic junction obstruction.
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Patched Receptors Sense, Interpret, and Establish an Epidermal Hedgehog Signaling Gradient
Journal of Investigative Dermatology, 2016Co-Authors: Christelle Adolphe, Jan Phillipp Junker, Anna Lyubimova, Alexander Van Oudenaarden, Brandon J. WainwrightAbstract:By using the sensitivity of single-molecule fluorescent in situ hybridization, we have precisely quantified the levels and defined the temporal and spatial distribution of Hedgehog signaling activity during embryonic skin development and discovered that there is a Hedgehog signaling gradient along the proximal-distal axis of developing hair follicles. To explore the contribution of Hedgehog receptors Ptch1 and PTCH2 in establishing the epidermal signaling gradient, we quantitated the level of pathway activity generated in Ptch1- and Ptch1;PTCH2-deficient skin and defined the contribution of each receptor to regulation of the levels of Hedgehog signaling identified in wild-type skin. Moreover, we show that both the cellular phenotype and level of pathway activity featured in Ptch1;PTCH2-deficient cells faithfully recapitulates the Peak level of endogenous Hedgehog signaling detected at the base of developing follicles, where the concentration of endogenous Shh is predicted to be highest. Taken together, these data show that both Ptch1 and PTCH2 play a crucial role in sensing the concentration of Hedgehog ligand and regulating the appropriate dose-dependent response.
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Patched 1 and Patched 2 Redundancy Has a Key Role in Regulating Epidermal Differentiation
Journal of Investigative Dermatology, 2014Co-Authors: Christelle Adolphe, Erica Nieuwenhuis, Rehan M. Villani, Zhu Juan Li, Pritinder Kaur, Brandon J. WainwrightAbstract:The Patched 1 (Ptch1) receptor has a pivotal role in inhibiting the activity of the Hedgehog (Hh) pathway and is therefore critical in preventing the onset of many human developmental disorders and tumor formation. However, the functional role of the mammalian PTCH2 paralogue remains elusive, particularly the extent to which it contributes to regulating the spatial and temporal activity of Hh signaling. Here we demonstrate in three independent mouse models of epidermal development that in vivo ablation of both Ptch receptors results in a more severe phenotype than loss of Ptch1 alone. Our studies indicate that concomitant loss of Ptch1 and PTCH2 activity inhibits epidermal lineage specification and differentiation. These results reveal that repression of Hh signaling through a dynamic Ptch regulatory network is a crucial event in lineage fate determination in the skin. In general, our findings implicate Ptch receptor redundancy as a key issue in elucidating the cellular origin of Hh-induced tumors.
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isolation and characterization of human patched 2 PTCH2 a putative tumour suppressor gene in basal cell carcinoma and medulloblastoma on chromosome 1p32
Human Molecular Genetics, 1999Co-Authors: Ian M Smyth, Monica Narang, T Evans, Cornelia Heimann, Yusuke Nakamura, Georgia Chenevixtrench, Torsten Pietsch, Carol Wicking, Brandon J. WainwrightAbstract:mutations of the human Patched gene (PTCH) have been identified in individuals with the nevoid basal cell carcinoma syndrome (NBCCS) as well as in sporadic basal cell carcinomas and medulloblastomas, We have isolated a homologue of this tumour suppressor gene and localized it to the short arm of chromosome 1 (1p32.1-32.3). Patched 2(PTCH2) comprises 22 coding exons and spans similar to 15 kb of genomic DNA, The gene encodes a 1203 amino acid putative transmembrane protein which is highly homologous to the PTCH product. We have characterized the genomic structure of PTCH2 and have used single-stranded conformational polymorphism analysis to search for mutations in PTCH2 in NBCCS patients, basal cell carcinomas and in medulloblastomas, To date, we have identified one truncating mutation in a medulloblastoma and a change in a splice donor site in a basal cell carcinoma, suggesting that the gene plays a role in the development of some tumours.
Veronique L. Veenstra - One of the best experts on this subject based on the ideXlab platform.
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Patched-2 functions to limit Patched-1 deficient skin cancer growth
Cellular Oncology, 2018Co-Authors: Veronique L. Veenstra, Ilse Dingjan, Cynthia Waasdorp, Helene Damhofer, Hanneke W. Laarhoven, Jan Paul Medema, Maarten F. BijlsmaAbstract:Purpose Basal cell carcinoma (BCC) is one of the most common skin cancers, and is typically driven by an aberrantly activated Hedgehog (Hh) pathway. The Hh pathway is regulated by interactions between the Patched-1 (Ptch1) and Smoothened (Smo) receptors. Smo is an activating receptor and is subject to inhibition by Ptch1. Following ligand binding to Ptch1, its inhibitory action is relieved and pathway activation occurs. This receptor interaction is pivotal to restraining uncontrolled cellular growth. Both receptors have been found to be frequently mutated in BCCs. PTCH2 is a Ptch1 paralog that exhibits overlapping functions in both normal development and tissue homeostasis. As yet, its contribution to cancer growth is poorly defined. Here we set out to assess how PTCH2 inhibits BCC growth. Methods We used several in vitro readouts for transcriptional and chemotactic Hh signaling in BCC-derived ASZ001 cells, and a novel xenograft model to assess in vivo BCC tumor growth. Gene editing by TALEN was used to untangle the different PTCH2-dependent responses to its ligand sonic hedgehog (Shh). Results We first defined the signaling competence of PTCH2 in Ptch1-deficient ASZ001 cells in vitro, and found that PTCH2 ligand binding drives their migration rather than eliciting a transcriptional response. We found that subsequent targeting of PTCH2 abrogated the chemotaxic effect. Next, we tested the contribution of PTCH2 to in vivo tumor growth using a xenograft model and found that reduced Ptch function results in increased tumor growth, but that selective pressure appatently acts against complete PTCH2 ablation. Conclusions We conclude that like Ptch1, PTCH2 exerts a tumor-suppressive function in BCC cells, and that after targeting of both paralogs, ligand-independent activation of the Hh pathway contributes to tumor growth.
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Patched-2 functions to limit Patched-1 deficient skin cancer growth
Cellular Oncology, 2018Co-Authors: Veronique L. Veenstra, Ilse Dingjan, Cynthia Waasdorp, Helene Damhofer, Hanneke W. Laarhoven, Jan Paul Medema, Maarten F. BijlsmaAbstract:Purpose Basal cell carcinoma (BCC) is one of the most common skin cancers, and is typically driven by an aberrantly activated Hedgehog (Hh) pathway. The Hh pathway is regulated by interactions between the Patched-1 (Ptch1) and Smoothened (Smo) receptors. Smo is an activating receptor and is subject to inhibition by Ptch1. Following ligand binding to Ptch1, its inhibitory action is relieved and pathway activation occurs. This receptor interaction is pivotal to restraining uncontrolled cellular growth. Both receptors have been found to be frequently mutated in BCCs. PTCH2 is a Ptch1 paralog that exhibits overlapping functions in both normal development and tissue homeostasis. As yet, its contribution to cancer growth is poorly defined. Here we set out to assess how PTCH2 inhibits BCC growth.