Targeting Hedgehog pathway by Smoothened Antagonist
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE171689 | GEO | 2021/07/08
REPOSITORIES: GEO
Similar Datasets
Project description:Mutations in Hedgehog (Hh) pathway genes, leading to constitutive activation of Smoothened (Smo), occur in sporadic medulloblastoma, the most common brain cancer in children. Antagonists of Smo induce tumor regression in mouse models of medulloblastoma and hold great promise for targeted therapy for this tumor. However, acquired resistance has emerged as one of the major challenges of targeted cancer therapy. Here, we describe novel mechanisms of acquired resistance to Smo antagonists in medulloblastoma. NVP-LDE225, a potent and selective Smo antagonist, inhibits Hh signaling and induces tumor regressions in allograft models of medulloblastoma that are driven by mutations of Patched (Ptch), a tumor suppressor in the Hh pathway. However, after long-term treatment, evidence of acquired resistance was observed. Genome-wide profiling of resistant tumors revealed distinct mechanisms to evade the inhibitory effects of Smo antagonists. Chromosomal amplification of Gli2, a downstream effector of Hh signaling, reactivated Hh signaling and restored tumor growth. Analysis of pathway gene-expression signatures selectively deregulated in resistant tumors identified increased phosphoinosite-3-kinase (PI3K) signaling as another potential resistance mechanism. Probing the functional relevance of increased PI3K signaling, we showed that the combination of NVP-LDE225 with the dual PI3K/mTOR inhibitor NVP-BEZ235 markedly delayed the development of resistance. Our findings have important clinical implications for future treatment strategies in medulloblastoma. mRNA profiling: RNA was prepared from tumours from vehicle or NVP-LDE225 treated nude mice allografted with medulloblastoma tumors derived from Ptch+/-p53-/- transgenic mouse and hybridized on Affymetrix Mouse Genome 430 2.0 RNA expression array. The dosage terminology (BID & QD) reflects the dosing schedule, where BID = twice a day, QD = once a day. aCGH: DNA was prepared from tumors from vehicle or NVP-LDE225 treated nude mice allografted with medulloblastoma tumors derived from Ptch+/-p53-/- transgenic mouse and hybridized on Agilent mouse CGH 244K Array.
2010-09-29 | E-GEOD-19657 | biostudies-arrayexpress
Project description:Mutations in Hedgehog (Hh) pathway genes, leading to constitutive activation of Smoothened (Smo), occur in sporadic medulloblastoma, the most common brain cancer in children. Antagonists of Smo induce tumor regression in mouse models of medulloblastoma and hold great promise for targeted therapy for this tumor. However, acquired resistance has emerged as one of the major challenges of targeted cancer therapy. Here, we describe novel mechanisms of acquired resistance to Smo antagonists in medulloblastoma. NVP-LDE225, a potent and selective Smo antagonist, inhibits Hh signaling and induces tumor regressions in allograft models of medulloblastoma that are driven by mutations of Patched (Ptch), a tumor suppressor in the Hh pathway. However, after long-term treatment, evidence of acquired resistance was observed. Genome-wide profiling of resistant tumors revealed distinct mechanisms to evade the inhibitory effects of Smo antagonists. Chromosomal amplification of Gli2, a downstream effector of Hh signaling, reactivated Hh signaling and restored tumor growth. Analysis of pathway gene-expression signatures selectively deregulated in resistant tumors identified increased phosphoinosite-3-kinase (PI3K) signaling as another potential resistance mechanism. Probing the functional relevance of increased PI3K signaling, we showed that the combination of NVP-LDE225 with the dual PI3K/mTOR inhibitor NVP-BEZ235 markedly delayed the development of resistance. Our findings have important clinical implications for future treatment strategies in medulloblastoma.
2010-09-29 | GSE19657 | GEO
Project description:The Hedgehog (Hh) pathway is essential for tissue homeostasis, and misregulation of this cascade drives several cancers. To control expression of pathway target genes, the G protein-coupled receptor (GPCR) Smoothened (SMO) activates glioma-associated (GLI) transcription factors via an unknown mechanism. Here we show that, rather than conforming to traditional GPCR signaling paradigms, SMO activates GLI by binding and sequestering protein kinase A (PKA) catalytic subunits at the membrane. This sequestration, triggered by GPCR kinase 2 (GRK2)-mediated phosphorylation of SMO intracellular domains, prevents PKA from phosphorylating soluble substrates, releasing GLI from PKA-mediated inhibition. Our work provides a mechanism directly linking vertebrate Hh signal transduction at the membrane to transcription factor activation in the nucleus. In contrast to existing models, our work shows that this aspect of Hh signaling is fundamentally similar between species. The mechanism described here may apply broadly to other GPCR- and PKA-containing cascades.
2021-04-25 | PXD019346 | Pride
Project description:Aberrant activation of the Hedgehog (Hh) signaling pathway is implicated in the pathogenesis of many cancers, including medulloblastoma and basal cell carcinoma (BCC). In this study, using neonatally irradiated Ptch1+/- mice as a model of Hh-dependent tumors, we investigated the in vivo effects of MK-4101, a novel SMO antagonist, for treatment of medulloblastoma and BCC. Results clearly demonstrate a robust antitumor activity of MK-4101, achieved through the inhibition of proliferation and induction of extensive apoptosis in tumor cells. Of note, beside antitumor activity on transplanted tumors, MK-4101 was highly efficacious against primary medulloblastoma and BCC developing in the cerebellum and skin of Ptch1+/- mice. By identifying the changes induced by MK-4101 in gene expression profiles in tumors, we also elucidate the mechanism of action of this novel, orally administrable compound. MK-4101 targets the Hh pathway in the tumor cells, showing the maximum inhibitory effect on Gli1 activity. MK-4101 also induced deregulation of cell cycle and block of DNA replication in tumors. Members of the IGF and Wnt signaling pathways , were among the most highly deregulated genes by MK-4101, suggesting that the interplay among Hh, IGF and Wnt is crucial in Hh-dependent tumorigenesis. Altogether, the results of this preclinical study support a therapeutic opportunity for MK-4101 in the treatment of Hh-driven cancers, also providing useful information for combination therapy with drugs targeting pathways cooperating with Hh oncogenic activity. Gene expression data was generated (in replicates) from Medulloblastoma allografts collected at various time points and following low (40mpk) or high (80 mpk) or vehicle single dose (QD) or mutiple dose (BID) treatment with a SHH pathway inhibitor.
2016-03-14 | E-GEOD-77042 | biostudies-arrayexpress
Project description:Aberrant activation of the Hedgehog (Hh) signaling pathway is implicated in the pathogenesis of many cancers, including medulloblastoma and basal cell carcinoma (BCC). In this study, using neonatally irradiated Ptch1+/- mice as a model of Hh-dependent tumors, we investigated the in vivo effects of MK-4101, a novel SMO antagonist, for treatment of medulloblastoma and BCC. Results clearly demonstrate a robust antitumor activity of MK-4101, achieved through the inhibition of proliferation and induction of extensive apoptosis in tumor cells. Of note, beside antitumor activity on transplanted tumors, MK-4101 was highly efficacious against primary medulloblastoma and BCC developing in the cerebellum and skin of Ptch1+/- mice. By identifying the changes induced by MK-4101 in gene expression profiles in tumors, we also elucidate the mechanism of action of this novel, orally administrable compound. MK-4101 targets the Hh pathway in the tumor cells, showing the maximum inhibitory effect on Gli1 activity. MK-4101 also induced deregulation of cell cycle and block of DNA replication in tumors. Members of the IGF and Wnt signaling pathways , were among the most highly deregulated genes by MK-4101, suggesting that the interplay among Hh, IGF and Wnt is crucial in Hh-dependent tumorigenesis. Altogether, the results of this preclinical study support a therapeutic opportunity for MK-4101 in the treatment of Hh-driven cancers, also providing useful information for combination therapy with drugs targeting pathways cooperating with Hh oncogenic activity.
2016-03-14 | GSE77042 | GEO
Project description:Hedgehog (Hh) signaling is critical for organogenesis, tissue homeostasis, and stem cell maintenance. Smoothened (SMO), the primary effector of Hh signaling, is expressed ectopically in human breast cancer, as well as in other cancers. Constitutive activation of SMO in mouse mammary glands leads to paracrine stimulation of proliferation, as well as hyperplasia. In canonical signaling, SMO functions via GLI transcription factor activation. However, recent data from Drosophila and mammalian cell lines indicate that SMO can function non-canonically as a G-protein coupled receptor (GPCR) by coupling to heterotrimeric G proteins, particularly those in the pertussis toxin (PTX)-sensitive G-alpha-i (Gai) class. Whether SMO functions as a GPCR in mammalian tissues in vivo is not known. Using genetically modified mouse models, we demonstrate here that SMO-induced stimulation of proliferation is PTX sensitive, and requires Gai2, but not Gai1 or Gai3. Our findings provide evidence for a non-canonical GPCR function of activated SMO in vivo, a finding that may have clinical significance given that most SMO-targeted agents were selected based largely on their ability to block canonical GLI-mediated transcription. Primary mammary epithelial cell RNA was deep-sequenced from mT-mG/SmoM2;MMTV-Cre (EGFP), mT-mG/SmoM2;MMTV-Cre (tdTomato), and mT-mG/SmoM2;+ cells to examine the effects of SmoM2 overexpression in the mammary gland.
2015-09-08 | E-GEOD-70210 | biostudies-arrayexpress
Project description:The Hedgehog (Hh) signaling pathway regulates normal development and cell proliferation, whereas its aberrant activation causes tumor formation. Hh-induced tumors can arise from different tissues and can be indolent or highly aggressive, such as basal cell carcinoma (BCC) of the skin and neural progenitor-derived medulloblastoma (MB), respectively. Little is known about cell-intrinsic factors that control the development of such diverse Hh-dependent tumors. Transcription factor Zfx is required for the self-renewal of several stem cell types, whereas its role in malignant transformation remains controversial. We found that the deletion of Zfx prevented BCC formation and significantly delayed MB development caused by Hh activation in vivo. In contrast, Zfx was dispensable for the development of Hh-independent brain tumor glioblastoma. We used genome-wide expression and chromatin binding analysis in a human MB cell line to identify direct, evolutionarily conserved targets of Zfx. These targets included the Hh signal transducer Smoothened (Smo), suggesting that Zfx may directly control Hh pathway activation in tumors. Two additional targets of Zfx, Dis3L and Ube2j1, were also required for the growth of MB cells in vitro. These results identify a common cell-intrinsic regulator of diverse Hh-induced tumors, and suggest Zfx and Zfx-controlled genes as possible therapeutic targets in these malignancies.
2014-12-31 | GSE45394 | GEO
Project description:The Hedgehog (Hh) signaling pathway regulates normal development and cell proliferation, whereas its aberrant activation causes tumor formation. Hh-induced tumors can arise from different tissues and can be indolent or highly aggressive, such as basal cell carcinoma (BCC) of the skin and neural progenitor-derived medulloblastoma (MB), respectively. Little is known about cell-intrinsic factors that control the development of such diverse Hh-dependent tumors. Transcription factor Zfx is required for the self-renewal of several stem cell types, whereas its role in malignant transformation remains controversial. We found that the deletion of Zfx prevented BCC formation and significantly delayed MB development caused by Hh activation in vivo. In contrast, Zfx was dispensable for the development of Hh-independent brain tumor glioblastoma. We used genome-wide expression and chromatin binding analysis in a human MB cell line to identify direct, evolutionarily conserved targets of Zfx. These targets included the Hh signal transducer Smoothened (Smo), suggesting that Zfx may directly control Hh pathway activation in tumors. Two additional targets of Zfx, Dis3L and Ube2j1, were also required for the growth of MB cells in vitro. These results identify a common cell-intrinsic regulator of diverse Hh-induced tumors, and suggest Zfx and Zfx-controlled genes as possible therapeutic targets in these malignancies.
2014-12-31 | GSE45265 | GEO
Project description:Smoothened inhibitors are currently being investigated for the treatment of several cancers. Vismodegib is approved for the treatment of locally advanced and metastatic basal cell carcinoma (BCC). The majority of BCC patients treated with vismodegib experience significant clinical benefit, however, a small number of patients develop resistance. Knowledge of resistance mechanisms can generate predictive biomarkers and is critical for the design of additional therapeutic strategies aimed at circumventing resistance. To investigate mechanisms of resistance to vismodegib in BCC we sequenced and profiled biopsies from patients who initially responded to treatment and subsequently progressed on drug. We find that resistance is associated with re-activation of the Hedgehog (Hh) pathway through diverse mechanisms, including concurrent copy number alterations in the downstream Hh pathway components SUFU and GLI2, as well as novel SMO mutations that reduce sensitivity to vismodegib. The latter fall into two classes: those that activate SMO and those that directly affect the vismodegib-binding pocket. Additionally, we observe evidence of clonal selection of SMO mutations and intra-tumor heterogeneity of resistance mechanisms, which implies diverse and combinatorial strategies are required to overcome resistance.
| EGAS00001000845 | EGA
Project description:Hedgehog (Hh) signaling is critical for organogenesis, tissue homeostasis, and stem cell maintenance. Smoothened (SMO), the primary effector of Hh signaling, is expressed ectopically in human breast cancer, as well as in other cancers. Constitutive activation of SMO in mouse mammary glands leads to paracrine stimulation of proliferation, as well as hyperplasia. In canonical signaling, SMO functions via GLI transcription factor activation. However, recent data from Drosophila and mammalian cell lines indicate that SMO can function non-canonically as a G-protein coupled receptor (GPCR) by coupling to heterotrimeric G proteins, particularly those in the pertussis toxin (PTX)-sensitive G-alpha-i (Gai) class. Whether SMO functions as a GPCR in mammalian tissues in vivo is not known. Using genetically modified mouse models, we demonstrate here that SMO-induced stimulation of proliferation is PTX sensitive, and requires Gai2, but not Gai1 or Gai3. Our findings provide evidence for a non-canonical GPCR function of activated SMO in vivo, a finding that may have clinical significance given that most SMO-targeted agents were selected based largely on their ability to block canonical GLI-mediated transcription.
2015-09-08 | GSE70210 | GEO