GLI2; GLI family zinc finger 2 (2q14)

Gene Summary

Gene:GLI2; GLI family zinc finger 2
Aliases: CJS, HPE9, PHS2, THP1, THP2
Summary:This gene encodes a protein which belongs to the C2H2-type zinc finger protein subclass of the Gli family. Members of this subclass are characterized as transcription factors which bind DNA through zinc finger motifs. These motifs contain conserved H-C links. Gli family zinc finger proteins are mediators of Sonic hedgehog (Shh) signaling and they are implicated as potent oncogenes in the embryonal carcinoma cell. The protein encoded by this gene localizes to the cytoplasm and activates patched Drosophila homolog (PTCH) gene expression. It is also thought to play a role during embryogenesis. The encoded protein is associated with several phenotypes- Greig cephalopolysyndactyly syndrome, Pallister-Hall syndrome, preaxial polydactyly type IV, postaxial polydactyly types A1 and B. [provided by RefSeq, Jul 2008]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:zinc finger protein GLI2
Updated:14 December, 2014


What does this gene/protein do?
Show (60)


What pathways are this gene/protein implicaed in?
- Sonic Hedgehog (Shh) Pathway BIOCARTA
- Hedgehog signaling pathway KEGG
Data from KEGG and BioCarta [BIOCARTA terms] via CGAP

Cancer Overview

Research Indicators

Publications Per Year (1989-2014)
Graph generated 14 December 2014 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • siRNA
  • Pyrimidines
  • Drug Resistance
  • Hedgehog Proteins
  • Base Sequence
  • Cell Surface Receptors
  • Cancer Types
  • Transforming Growth Factor beta
  • Down-Regulation
  • Western Blotting
  • Immunohistochemistry
  • Kruppel-Like Transcription Factors
  • Basal Cell Carcinoma (BCC) - Skin
  • Chromosome 2
  • Cell Survival
  • Signal Transduction
  • Keratinocytes
  • Transcription Factors
  • Cancer Gene Expression Regulation
  • Nerve Tissue Proteins
  • Mutation
  • Bladder Cancer
  • Trans-Activators
  • Cell Proliferation
  • Oligonucleotide Array Sequence Analysis
  • Apoptosis
  • Pyridines
  • Young Adult
  • Gene Expression Profiling
  • Neoplastic Cell Transformation
  • G-Protein-Coupled Receptors
  • rho-Associated Kinases
  • Oncogene Proteins
  • Childhood Cancer
  • Nuclear Proteins
  • Mice, Transgenic
  • Antineoplastic Agents
  • Transcription
  • Messenger RNA
  • Proto-Oncogene Proteins
  • GLI2
Tag cloud generated 14 December, 2014 using data from PubMed, MeSH and CancerIndex

Notable (3)

Scope includes mutations and abnormal protein expression.

Entity Topic PubMed Papers
Skin, Basal Cell CarcinomaGLI2 and Basal Cell Carcinoma (BCC) - Skin View Publications12
Childhood CancersGLI2 and Childhood Cancer View Publications10
Bladder CancerGLI2 and Bladder Cancer View Publications2

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Related Links

Latest Publications: GLI2 (cancer-related)

Li N, Chen M, Truong S, et al.
Determinants of Gli2 co-activation of wildtype and naturally truncated androgen receptors.
Prostate. 2014; 74(14):1400-10 [PubMed] Related Publications
BACKGROUND: Gli2, a transcription factor in the Hedgehog pathway, is overexpressed in castrate-resistant prostate cancer (PCa). Previously we showed that Gli2 overexpression increased transcriptional activity of androgen receptor (AR) and conferred androgen growth-independence to normally growth-dependent PCa cells. Here we localized the regions of AR-Gli2 protein interaction and determined the domains within Gli2 needed for AR co-activation.
METHODS: Co-immunoprecipitation and GST-pulldown assays were used to define AR-Gli binding domains. Co-activation assays using androgen-responsive promoter reporters were used to define Gli2 regions needed for AR co-activation. Chromatin immunoprecipitation (ChIP) assays were used to confirm nuclear interactions of Gli2 with AR in PCa cells.
RESULTS: The Gli2 C-terminal domain (CTD) is sufficient for AR co-activation. Two elements within the CTD were required: (1) an AR binding domain within aa628-897; and (2) at least part of the Gli2 transactivation domain within aa1252-1586. In turn, Gli2 binds the tau5/AF5 ligand-independent activation domain in the AR N-terminus. Mutations in the WxxLF motif in tau5/AF5 greatly diminished binding to Gli2-CTD. Gli2 interaction with AR tau5/AF5 was further substantiated by the ability of Gli2/Gli2-CTD to co-activate truncated AR splice variants (AR-V7/ARV567es). ChIP assays confirmed that Gli2 associates with chromatin at androgen response elements found near androgen-responsive genes in LNCaP cells. These assays also showed that AR associates with chromatin containing a Gli-response element near a Gli-responsive gene.
CONCLUSION: Our findings indicate that Gli2 overexpression in PCa cells might support development of castration resistant PCa through AR co-activation and suggests that AR might modulate transcription from Gli2.

Related: Prostate Cancer GLI

Tang Y, Gholamin S, Schubert S, et al.
Epigenetic targeting of Hedgehog pathway transcriptional output through BET bromodomain inhibition.
Nat Med. 2014; 20(7):732-40 [PubMed] Article available free on PMC after 01/01/2015 Related Publications
Hedgehog signaling drives oncogenesis in several cancers, and strategies targeting this pathway have been developed, most notably through inhibition of Smoothened (SMO). However, resistance to Smoothened inhibitors occurs by genetic changes of Smoothened or other downstream Hedgehog components. Here we overcome these resistance mechanisms by modulating GLI transcription through inhibition of bromo and extra C-terminal (BET) bromodomain proteins. We show that BRD4 and other BET bromodomain proteins regulate GLI transcription downstream of SMO and suppressor of fused (SUFU), and chromatin immunoprecipitation studies reveal that BRD4 directly occupies GLI1 and GLI2 promoters, with a substantial decrease in engagement of these sites after treatment with JQ1, a small-molecule inhibitor targeting BRD4. Globally, genes associated with medulloblastoma-specific GLI1 binding sites are downregulated in response to JQ1 treatment, supporting direct regulation of GLI activity by BRD4. Notably, patient- and GEMM (genetically engineered mouse model)-derived Hedgehog-driven tumors (basal cell carcinoma, medulloblastoma and atypical teratoid rhabdoid tumor) respond to JQ1 even when harboring genetic lesions rendering them resistant to Smoothened antagonists. Altogether, our results reveal BET proteins as critical regulators of Hedgehog pathway transcriptional output and nominate BET bromodomain inhibitors as a strategy for treating Hedgehog-driven tumors with emerged or a priori resistance to Smoothened antagonists.

Related: Signal Transduction

Santini R, Pietrobono S, Pandolfi S, et al.
SOX2 regulates self-renewal and tumorigenicity of human melanoma-initiating cells.
Oncogene. 2014; 33(38):4697-708 [PubMed] Article available free on PMC after 01/01/2015 Related Publications
Melanoma is one of the most aggressive types of human cancer, characterized by enhanced heterogeneity and resistance to conventional therapy at advanced stages. We and others have previously shown that HEDGEHOG-GLI (HH-GLI) signaling is required for melanoma growth and for survival and expansion of melanoma-initiating cells (MICs). Recent reports indicate that HH-GLI signaling regulates a set of genes typically expressed in embryonic stem cells, including SOX2 (sex-determining region Y (SRY)-Box2). Here we address the function of SOX2 in human melanomas and MICs and its interaction with HH-GLI signaling. We find that SOX2 is highly expressed in melanoma stem cells. Knockdown of SOX2 sharply decreases self-renewal in melanoma spheres and in putative melanoma stem cells with high aldehyde dehydrogenase activity (ALDH(high)). Conversely, ectopic expression of SOX2 in melanoma cells enhances their self-renewal in vitro. SOX2 silencing also inhibits cell growth and induces apoptosis in melanoma cells. In addition, depletion of SOX2 progressively abrogates tumor growth and leads to a significant decrease in tumor-initiating capability of ALDH(high) MICs upon xenotransplantation, suggesting that SOX2 is required for tumor initiation and for continuous tumor growth. We show that SOX2 is regulated by HH signaling and that the transcription factors GLI1 and GLI2, the downstream effectors of HH-GLI signaling, bind to the proximal promoter region of SOX2 in primary melanoma cells. In functional studies, we find that SOX2 function is required for HH-induced melanoma cell growth and MIC self-renewal in vitro. Thus SOX2 is a critical factor for self-renewal and tumorigenicity of MICs and an important mediator of HH-GLI signaling in melanoma. These findings could provide the basis for novel therapeutic strategies based on the inhibition of SOX2 for the treatment of a subset of human melanomas.

Related: Apoptosis Melanoma Signal Transduction Skin Cancer GLI SOX2 gene

Li G, Ci W, Karmakar S, et al.
SPOP promotes tumorigenesis by acting as a key regulatory hub in kidney cancer.
Cancer Cell. 2014; 25(4):455-68 [PubMed] Related Publications
Hypoxic stress and hypoxia-inducible factors (HIFs) play important roles in a wide range of tumors. We demonstrate that SPOP, which encodes an E3 ubiquitin ligase component, is a direct transcriptional target of HIFs in clear cell renal cell carcinoma (ccRCC). Furthermore, hypoxia results in cytoplasmic accumulation of SPOP, which is sufficient to induce tumorigenesis. This tumorigenic activity occurs through the ubiquitination and degradation of multiple regulators of cellular proliferation and apoptosis, including the tumor suppressor PTEN, ERK phosphatases, the proapoptotic molecule Daxx, and the Hedgehog pathway transcription factor Gli2. Knockdown of SPOP specifically kills ccRCC cells, indicating that it may be a promising therapeutic target. Collectively, our results indicate that SPOP serves as a regulatory hub to promote ccRCC tumorigenesis.

Related: Kidney Cancer Signal Transduction

Kool M, Jones DT, Jäger N, et al.
Genome sequencing of SHH medulloblastoma predicts genotype-related response to smoothened inhibition.
Cancer Cell. 2014; 25(3):393-405 [PubMed] Related Publications
Smoothened (SMO) inhibitors recently entered clinical trials for sonic-hedgehog-driven medulloblastoma (SHH-MB). Clinical response is highly variable. To understand the mechanism(s) of primary resistance and identify pathways cooperating with aberrant SHH signaling, we sequenced and profiled a large cohort of SHH-MBs (n = 133). SHH pathway mutations involved PTCH1 (across all age groups), SUFU (infants, including germline), and SMO (adults). Children >3 years old harbored an excess of downstream MYCN and GLI2 amplifications and frequent TP53 mutations, often in the germline, all of which were rare in infants and adults. Functional assays in different SHH-MB xenograft models demonstrated that SHH-MBs harboring a PTCH1 mutation were responsive to SMO inhibition, whereas tumors harboring an SUFU mutation or MYCN amplification were primarily resistant.

Related: Childhood Medulloblastoma / PNET AKT1 Signal Transduction TP53 MYCN (n-myc) TERT

Shih DJ, Northcott PA, Remke M, et al.
Cytogenetic prognostication within medulloblastoma subgroups.
J Clin Oncol. 2014; 32(9):886-96 [PubMed] Article available free on PMC after 20/03/2015 Related Publications
PURPOSE: Medulloblastoma comprises four distinct molecular subgroups: WNT, SHH, Group 3, and Group 4. Current medulloblastoma protocols stratify patients based on clinical features: patient age, metastatic stage, extent of resection, and histologic variant. Stark prognostic and genetic differences among the four subgroups suggest that subgroup-specific molecular biomarkers could improve patient prognostication.
PATIENTS AND METHODS: Molecular biomarkers were identified from a discovery set of 673 medulloblastomas from 43 cities around the world. Combined risk stratification models were designed based on clinical and cytogenetic biomarkers identified by multivariable Cox proportional hazards analyses. Identified biomarkers were tested using fluorescent in situ hybridization (FISH) on a nonoverlapping medulloblastoma tissue microarray (n = 453), with subsequent validation of the risk stratification models.
RESULTS: Subgroup information improves the predictive accuracy of a multivariable survival model compared with clinical biomarkers alone. Most previously published cytogenetic biomarkers are only prognostic within a single medulloblastoma subgroup. Profiling six FISH biomarkers (GLI2, MYC, chromosome 11 [chr11], chr14, 17p, and 17q) on formalin-fixed paraffin-embedded tissues, we can reliably and reproducibly identify very low-risk and very high-risk patients within SHH, Group 3, and Group 4 medulloblastomas.
CONCLUSION: Combining subgroup and cytogenetic biomarkers with established clinical biomarkers substantially improves patient prognostication, even in the context of heterogeneous clinical therapies. The prognostic significance of most molecular biomarkers is restricted to a specific subgroup. We have identified a small panel of cytogenetic biomarkers that reliably identifies very high-risk and very low-risk groups of patients, making it an excellent tool for selecting patients for therapy intensification and therapy de-escalation in future clinical trials.

Related: Chromosome 11 Chromosome 14 Cancer Cytogenetics FISH Childhood Medulloblastoma / PNET

Piirsoo A, Kasak L, Kauts ML, et al.
Protein kinase inhibitor SU6668 attenuates positive regulation of Gli proteins in cancer and multipotent progenitor cells.
Biochim Biophys Acta. 2014; 1843(4):703-14 [PubMed] Article available free on PMC after 20/03/2015 Related Publications
Observations that Glioma-associated transcription factors Gli1 and Gli2 (Gli1/2), executers of the Sonic Hedgehog (Shh) signaling pathway and targets of the Transforming Growth Factor β (TGF-β) signaling axis, are involved in numerous developmental and pathological processes unveil them as attractive pharmaceutical targets. Unc-51-like serine/threonine kinase Ulk3 has been suggested to play kinase activity dependent and independent roles in the control of Gli proteins in the context of the Shh signaling pathway. This study aimed at investigating whether the mechanism of generation of Gli1/2 transcriptional activators has similarities regardless of the signaling cascade evoking their activation. We also elucidate further the role of Ulk3 kinase in regulation of Gli1/2 proteins and examine SU6668 as an inhibitor of Ulk3 catalytic activity and a compound targeting Gli1/2 proteins in different cell-based experimental models. Here we demonstrate that Ulk3 is required not only for maintenance of basal levels of Gli1/2 proteins but also for TGF-β or Shh dependent activation of endogenous Gli1/2 proteins in human adipose tissue derived multipotent stromal cells (ASCs) and mouse immortalized progenitor cells, respectively. We show that cultured ASCs possess the functional Shh signaling axis and differentiate towards osteoblasts in response to Shh. Also, we demonstrate that similarly to Ulk3 RNAi, SU6668 prevents de novo expression of Gli1/2 proteins and antagonizes the Gli-dependent activation of the gene expression programs induced by either Shh or TGF-β. Our data suggest SU6668 as an efficient inhibitor of Ulk3 kinase allowing manipulation of the Gli-dependent transcriptional outcome.

Related: Cancer Prevention and Risk Reduction Signal Transduction GLI

Lesiak A, Sobolewska-Sztychny D, Danilewicz M, et al.
Sonic hedgehog pathway dysregulation in skin basal-cell carcinoma of a Polish population.
Folia Histochem Cytobiol. 2013; 51(3):219-24 [PubMed] Related Publications
Sonic hedgehog (Shh) pathway impairment plays a key role in the pathogenesis of basal-cell carcinomas (BCC), the most frequent skin tumor among Caucasians. Shh, Smo, and Gli2 family proteins are necessary for adequate and controlled cell proliferation. The aim of this study was to evaluate Shh, Smo, and Smo expression in BCC skin biopsies taken from sun-exposed areas. 41 BCC skin biopsies and 22 healthy skin specimens (the control group) taken from the same areas served as material for the study. All specimens were immunohistochemically stained with monoclonal antibodies directed against the chosen proteins. Shh and Smo expression (cytoplasmic pattern) were recorded semiquantitatively using a four-grade score (0-3). Gli2 expression (nuclear pattern) was determined using an image analysis system (semiautomatic function). The immunoexpression of the Shh and Smo proteins significantly increased in the BCC group, as compared with the normal controls (for Shh, the mean intensity was 1.67 in BCC vs. 1.17 in the control group, p < 0.001; for Smo, the mean intensity was 1.46 in BCC vs. 0.99 in the control group, p < 0.001). The staining for Gli2 in the BCC group was completely negative, but indicated the presence of Gli2 in the control patients (1.15 Gli2+ cells/100 cells). Sonic hedgehog pathway dysregulation may play an important role in skin cancerogenesis leading to BCC development.

Related: Basal Cell Carcinoma Skin Cancer

Inaguma S, Riku M, Hashimoto M, et al.
GLI1 interferes with the DNA mismatch repair system in pancreatic cancer through BHLHE41-mediated suppression of MLH1.
Cancer Res. 2013; 73(24):7313-23 [PubMed] Related Publications
The mismatch repair (MMR) system is indispensable for the fidelity of DNA replication, the impairment of which predisposes to the development and progression of many types of cancers. To date, GLI1 transcription factor, a key molecule of the Hedgehog signaling pathway, has been shown to regulate the expression of several genes crucial for a variety of cancer cell properties in many types of cancers, including pancreatic ductal adenocarcinoma (PDAC), but whether GLI1 could control the MMR system was not known. Here, we showed that GLI1 and GLI2 indirectly suppressed the expression of MLH1 in PDAC cells. Through GLI1 target gene screening, we found that GLI1 and GLI2 activated the expression of a basic helix-loop-helix type suppressor BHLHE41/DEC2/SHARP1 through a GLI-binding site in the promoter. Consistent with a previous report that BHLHE41 suppresses the MLH1 promoter activity, we found that the activation of GLI1 led to the BHLHE41-dependent suppression of MLH1, and a double knockdown of GLI1 and GLI2 conversely increased the MLH1 protein in PDAC cells. Using TALEN-based modification of the MLH1 gene, we further showed that GLI1 expression was indeed associated with an increased tolerance to a methylating agent, methylnitrosourea cooperatively with a lower copy number status of MLH1. Finally, GLI1 expression was immunohistochemically related positively with BHLHE41 and inversely with MLH1 in PDAC cells and precancerous lesions of the pancreas. On the basis of these results, we propose that GLI1 depresses the MMR activity and might contribute to the development and progression of PDAC.

Related: Cancer of the Pancreas Pancreatic Cancer Signal Transduction GLI MLH1

Lo WW, Wunder JS, Dickson BC, et al.
Involvement and targeted intervention of dysregulated Hedgehog signaling in osteosarcoma.
Cancer. 2014; 120(4):537-47 [PubMed] Related Publications
BACKGROUND: During development, the Hedgehog pathway plays important roles regulating the proliferation and differentiation of chondrocytes, providing a template for growing bone. In this study, the authors investigated the components of dysregulated Hedgehog signaling as potential therapeutic targets for osteosarcoma.
METHODS: Small-molecule agonists and antagonists that modulate the Hedgehog pathway at different levels were used to investigate the mechanisms of dysregulation and the efficacy of Hedgehog blockade in osteosarcoma cell lines. The inhibitory effect of a small-molecule Smoothened (SMO) antagonist, IPI-926 (saridegib), also was examined in patient-derived xenograft models.
RESULTS: An inverse correlation was identified in osteosarcoma cell lines between endogenous glioma-associated oncogene 2 (GLI2) levels and Hedgehog pathway induction levels. Cells with high levels of GLI2 were sensitive to GLI inhibition, but not SMO inhibition, suggesting that GLI2 overexpression may be a mechanism of ligand-independent activation. In contrast, cells that expressed high levels of the Hedgehog ligand gene Indian hedgehog (IHH) and the target genes patched 1 (PTCH1) and GLI1 were sensitive to modulation of both SMO and GLI, suggesting ligand-dependent activation. In 2 xenograft models, active autocrine and paracrine, ligand-dependent Hedgehog signaling was identified. IPI-926 inhibited the Hedgehog signaling interactions between the tumor and the stroma and demonstrated antitumor efficacy in 1 of 2 ligand-dependent models.
CONCLUSIONS: The current results indicate that both ligand-dependent and ligand-independent Hedgehog dysregulation may be involved in osteosarcoma. It is the first report to demonstrate Hedgehog signaling crosstalk between the tumor and the stroma in osteosarcoma. The inhibitory effect of IPI-926 warrants additional research and raises the possibility of using Hedgehog pathway inhibitors as targeted therapeutics to improve treatment for osteosarcoma.

Related: Bone Cancers Osteosarcoma Signal Transduction GLI

Dakhova O, Rowley D, Ittmann M
Genes upregulated in prostate cancer reactive stroma promote prostate cancer progression in vivo.
Clin Cancer Res. 2014; 20(1):100-9 [PubMed] Article available free on PMC after 01/01/2015 Related Publications
PURPOSE: Marked reactive stroma formation is associated with poor outcome in clinically localized prostate cancer. We have previously identified genes with diverse functions that are upregulated in reactive stroma. This study tests the hypothesis that expression of these genes in stromal cells enhances prostate cancer growth in vivo.
EXPERIMENTAL DESIGN: The expression of reactive stroma genes in prostate stromal cell lines was evaluated by reverse transcriptase (RT)-PCR and qRT-PCR. Genes were knocked down using stable expression of short-hairpin RNAs (shRNA) and the impact on tumorigenesis assessed using the differential reactive stroma (DRS) system, in which prostate stromal cell lines are mixed with LNCaP prostate cancer cells and growth as subcutaneous xenografts assessed.
RESULTS: Nine of 10 reactive stroma genes tested were expressed in one or more prostate stromal cell lines. Gene knockdown of c-Kit, Wnt10B, Bmi1, Gli2, or COMP all resulted in decreased tumorigenesis in the DRS model. In all tumors analyzed, angiogenesis was decreased and there were variable effects on proliferation and apoptosis in the LNCaP cells. Wnt10B has been associated with stem/progenitor cell phenotype in other tissue types. Using a RT-PCR array, we detected downregulation of multiple genes involved in stem/progenitor cell biology such as OCT4 and LIF as well as cytokines such as VEGFA, BDNF, and CSF2 in cells with Wnt10B knockdown.
CONCLUSIONS: These findings show that genes upregulated in prostate cancer-reactive stroma promote progression when expressed in prostate stromal cells. Moreover, these data indicate that the DRS model recapitulates key aspects of cancer cell/reactive stroma interactions in prostate cancer.

Related: Prostate Cancer

Laner-Plamberger S, Wolff F, Kaser-Eichberger A, et al.
Hedgehog/GLI signaling activates suppressor of cytokine signaling 1 (SOCS1) in epidermal and neural tumor cells.
PLoS One. 2013; 8(9):e75317 [PubMed] Article available free on PMC after 01/01/2015 Related Publications
Sustained hedgehog (Hh) signaling mediated by the GLI transcription factors is implicated in many types of cancer. Identification of Hh/GLI target genes modulating the activity of other pathways involved in tumor development promise to open new ways for better understanding of tumor development and maintenance. Here we show that SOCS1 is a direct target of Hh/GLI signaling in human keratinocytes and medulloblastoma cells. SOCS1 is a potent inhibitor of interferon gamma (IFN-y)/STAT1 signaling. IFN-у/STAT1 signaling can induce cell cycle arrest, apoptosis and anti-tumor immunity. The transcription factors GLI1 and GLI2 activate the SOCS1 promoter, which contains five putative GLI binding sites, and GLI2 binding to the promoter was shown by chromatin immunoprecipitation. Consistent with a role of GLI in SOCS1 regulation, STAT1 phosphorylation is reduced in cells with active Hh/GLI signaling and IFN-у/STAT1 target gene activation is decreased. Furthermore, IFN-у signaling is restored by shRNA mediated knock down of SOCS1. Here, we identify SOCS1 as a novel Hh/GLI target gene, indicating a negative role of Hh/GLI pathway in IFN-y/STAT1 signaling.

Related: Childhood Medulloblastoma / PNET Signal Transduction GLI

Shimada Y, Katsube K, Kabasawa Y, et al.
Integrated genotypic analysis of hedgehog-related genes identifies subgroups of keratocystic odontogenic tumor with distinct clinicopathological features.
PLoS One. 2013; 8(8):e70995 [PubMed] Article available free on PMC after 01/01/2015 Related Publications
Keratocystic odontogenic tumor (KCOT) arises as part of Gorlin syndrome (GS) or as a sporadic lesion. Gene mutations and loss of heterozygosity (LOH) of the hedgehog receptor PTCH1 plays an essential role in the pathogenesis of KCOT. However, some KCOT cases lack evidence for gene alteration of PTCH1, suggesting that other genes in the hedgehog pathway may be affected. PTCH2 and SUFU participate in the occurrence of GS-associated tumors, but their roles in KCOT development are unknown. To elucidate the roles of these genes, we enrolled 36 KCOT patients in a study to sequence their entire coding regions of PTCH1, PTCH2 and SUFU. LOH and immunohistochemical expression of these genes, as well as the downstream targets of hedgehog signaling, were examined using surgically-excised KCOT tissues. PTCH1 mutations, including four novel ones, were found in 9 hereditary KCOT patients, but not in sporadic KCOT patients. A pathogenic mutation of PTCH2 or SUFU was not found in any patients. LOH at PTCH1 and SUFU loci correlated with the presence of epithelial budding. KCOT harboring a germline mutation (Type 1) showed nuclear localization of GLI2 and frequent histological findings such as budding and epithelial islands, as well as the highest recurrence rate. KCOT with LOH but without a germline mutation (Type 2) less frequently showed these histological features, and the recurrence rate was lower. KCOT with neither germline mutation nor LOH (Type 3) consisted of two subgroups, Type 3A and 3B, which were characterized by nuclear and cytoplasmic GLI2 localization, respectively. Type 3B rarely exhibited budding and recurrence, behaving as the most amicable entity. The expression patterns of CCND1 and BCL2 tended to correlate with these subgroups. Our data indicates a significant role of PTCH1 and SUFU in the pathogenesis of KCOT, and the genotype-oriented subgroups constitute entities with different potential aggressiveness.

Related: Signal Transduction

Perrot CY, Gilbert C, Marsaud V, et al.
GLI2 cooperates with ZEB1 for transcriptional repression of CDH1 expression in human melanoma cells.
Pigment Cell Melanoma Res. 2013; 26(6):861-73 [PubMed] Related Publications
In melanoma cells, high expression of the transcription factor GLI2 is associated with increased invasive potential and loss of E-cadherin expression, an event reminiscent of the epithelial-to-mesenchymal transition (EMT). Herein, we provide evidence that GLI2 represses E-cadherin gene (CDH1) expression in melanoma cells via distinct mechanisms, enhancing transcription of the EMT-activator ZEB1 and cooperative repression of CDH1 gene transcription via direct binding of both GLI2 and ZEB1 to two closely positioned Kruppel-like factor-binding sites within the CDH1 promoter. GLI2 silencing rescued CDH1 expression except in melanoma cell lines in which the CDH1 promoter was hypermethylated. Proximity ligation assays identified GLI2-ZEB1 complexes in melanoma cell nuclei, proportional to endogenous GLI2 and ZEB1 expression, and whose accumulation was enhanced by the classical EMT inducer TGF-β. These data identify GLI2 as a critical modulator of the cadherin switch in melanoma, a molecular process that is critical for metastatic spread of the disease.

Related: Melanoma Skin Cancer CDH1

Gialmanidis IP, Bravou V, Petrou I, et al.
Expression of Bmi1, FoxF1, Nanog, and γ-catenin in relation to hedgehog signaling pathway in human non-small-cell lung cancer.
Lung. 2013; 191(5):511-21 [PubMed] Related Publications
BACKGROUND: Hedgehog signaling is known to be involved in both lung organogenesis and lung carcinogenesis. The aim of this study was to examine potential downstream targets of the hedgehog signaling pathway in non-small-cell lung cancer.
METHODS: Protein expression of Bmi1, FoxF1, Nanog, and γ-catenin was examined by immunohistochemistry in 80 non-small-cell lung cancer samples. Correlations with the previously immunohistochemically recovered results for sonic hedgehog, Ptch1, Smo, Gli1, and Gli2 in the same cohort of tumors as well as the clinicopathological characteristics of the tumors were also evaluated.
RESULTS: Bmi1 was expressed in 78/80 (97.5 %) cases of non-small-cell lung cancer and correlated with male gender and expression of Gli1. Positive expression of FoxF1 was found in 62/80 (77.5 %) cases. Expression of FoxF1 correlated with lymph node metastases, Bmi1, and hedgehog pathway activation. Overexpression of Nanog was also noted in 74/80 (92.5 %) tumors and correlated with Bmi1. Cytoplasmic accumulation of γ-catenin was observed in 85 % (68/80) of the tumors and correlated with the expression of Bmi1, FoxF1, and Nanog.
CONCLUSION: Several developmental pathways seem to be implicated in non-small-cell lung cancer. It is also suggested that Bmi1 and FoxF1 may cooperate with hedgehog signaling in non-small-cell lung carcinogenesis.

Related: Non-Small Cell Lung Cancer Lung Cancer Signal Transduction

Nakamura S, Nagano S, Nagao H, et al.
Arsenic trioxide prevents osteosarcoma growth by inhibition of GLI transcription via DNA damage accumulation.
PLoS One. 2013; 8(7):e69466 [PubMed] Article available free on PMC after 01/01/2015 Related Publications
The Hedgehog pathway is activated in various types of malignancies. We previously reported that inhibition of SMO or GLI prevents osteosarcoma growth in vitro and in vivo. Recently, it has been reported that arsenic trioxide (ATO) inhibits cancer growth by blocking GLI transcription. In this study, we analyzed the function of ATO in the pathogenesis of osteosarcoma. Real-time PCR showed that ATO decreased the expression of Hedgehog target genes, including PTCH1, GLI1, and GLI2, in human osteosarcoma cell lines. WST-1 assay and colony formation assay revealed that ATO prevented osteosarcoma growth. These findings show that ATO prevents GLI transcription and osteosarcoma growth in vitro. Flow cytometric analysis showed that ATO promoted apoptotic cell death. Comet assay showed that ATO treatment increased accumulation of DNA damage. Western blot analysis showed that ATO treatment increased the expression of γH2AX, cleaved PARP, and cleaved caspase-3. In addition, ATO treatment decreased the expression of Bcl-2 and Bcl-xL. These findings suggest that ATO treatment promoted apoptotic cell death caused by accumulation of DNA damage. In contrast, Sonic Hedgehog treatment decreased the expression of γH2AX induced by cisplatin treatment. ATO re-induced the accumulation of DNA damage attenuated by Sonic Hedgehog treatment. These findings suggest that ATO inhibits the activation of Hedgehog signaling and promotes apoptotic cell death in osteosarcoma cells by accumulation of DNA damage. Finally, examination of mouse xenograft models showed that ATO administration prevented the growth of osteosarcoma in nude mice. Because ATO is an FDA-approved drug for treatment of leukemia, our findings suggest that ATO is a new therapeutic option for treatment of patients with osteosarcoma.

Related: Apoptosis Cisplatin Osteosarcoma Signal Transduction GLI

Kanda S, Mitsuyasu T, Nakao Y, et al.
Anti-apoptotic role of the sonic hedgehog signaling pathway in the proliferation of ameloblastoma.
Int J Oncol. 2013; 43(3):695-702 [PubMed] Article available free on PMC after 01/01/2015 Related Publications
Sonic hedgehog (SHH) signaling pathway is crucial to growth and patterning during organogenesis. Aberrant activation of the SHH signaling pathway can result in tumor formation. We examined the expression of SHH signaling molecules and investigated the involvement of the SHH pathway in the proliferation of ameloblastoma, the most common benign tumor of the jaws. We used immunohistochemistry on ameloblastoma specimens and immunocytochemistry and reverse transcription-PCR on the ameloblastoma cell line AM-1. We also used the inhibitors of SHH signaling, SHH neutralizing antibody and cyclopamine, to assess the effects of SHH on the proliferation of AM-1 cells. We detected expression of SHH, patched, GLI1, GLI2 and GLI3 in the ameloblastoma specimens and AM-1 cells. The proliferation of these cells was significantly inhibited in the presence of SHH neutralizing antibody or cyclopamine; this was confirmed by BrdU incorporation assays. Furthermore, in the presence of SHH neutralizing antibody, nuclear translocation of GLI1 and GLI2 was abolished, apoptosis was induced, BCL-2 expression decreased and BAX expression increased. Our results suggest that the SHH signaling pathway is constitutively active in ameloblastoma and plays an anti-apoptotic role in the proliferation of ameloblastoma cells through autocrine loop stimulation.

Related: Apoptosis Signal Transduction

Lim CB, Prêle CM, Cheah HM, et al.
Mutational analysis of hedgehog signaling pathway genes in human malignant mesothelioma.
PLoS One. 2013; 8(6):e66685 [PubMed] Article available free on PMC after 01/01/2015 Related Publications
BACKGROUND: The Hedgehog (HH) signaling pathway is critical for embryonic development and adult homeostasis. Recent studies have identified regulatory roles for this pathway in certain cancers with mutations in the HH pathway genes. The extent to which mutations of the HH pathway genes are involved in the pathogenesis of malignant mesothelioma (MMe) is unknown.
METHODOLOGY/PRINCIPAL FINDINGS: Real-time PCR analysis of HH pathway genes PTCH1, GLI1 and GLI2 were performed on 7 human MMe cell lines. Exon sequencing of 13 HH pathway genes was also performed in cell lines and human MMe tumors. In silico programs were used to predict the likelihood that an amino-acid substitution would have a functional effect. GLI1, GLI2 and PTCH1 were highly expressed in MMe cells, indicative of active HH signaling. PTCH1, SMO and SUFU mutations were found in 2 of 11 MMe cell lines examined. A non-synonymous missense SUFU mutation (p.T411M) was identified in LO68 cells. In silico characterization of the SUFU mutant suggested that the p.T411M mutation might alter protein function. However, we were unable to demonstrate any functional effect of this mutation on Gli activity. Deletion of exons of the PTCH1 gene was found in JU77 cells, resulting in loss of one of two extracellular loops implicated in HH ligand binding and the intracellular C-terminal domain. A 3-bp insertion (69_70insCTG) in SMO, predicting an additional leucine residue in the signal peptide segment of SMO protein was also identified in LO68 cells and a MMe tumour.
CONCLUSIONS/SIGNIFICANCE: We identified the first novel mutations in PTCH1, SUFU and SMO associated with MMe. Although HH pathway mutations are relatively rare in MMe, these data suggest a possible role for dysfunctional HH pathway in the pathogenesis of a subgroup of MMe and help rationalize the exploration of HH pathway inhibitors for MMe therapy.

Related: Mesothelioma Signal Transduction

Ghanbari-Azarnier R, Sato S, Wei Q, et al.
Targeting stem cell behavior in desmoid tumors (aggressive fibromatosis) by inhibiting hedgehog signaling.
Neoplasia. 2013; 15(7):712-9 [PubMed] Article available free on PMC after 01/01/2015 Related Publications
Desmoid tumor (also called aggressive fibromatosis) is a lesion of mesenchymal origin that can occur as a sporadic tumor or a manifestation of the preneoplastic syndrome, familial adenomatous polyposis caused by a mutation in adenomatous polyposis coli (APC). This tumor type is characterized by the stabilization of β-catenin and activation of Tcf-mediated transcription. Cell transplantation data suggest that desmoid tumors are derived from mesenchymal progenitor cells (MSCs). As such, modulating cell signaling pathways that regulate MSC differentiation or proliferation, such as hedgehog (Hh) signaling, could alter the tumor phenotype. Here, we found that Hh signaling is activated in human and murine desmoid tumors. Inhibiting Hh signaling in human cell cultures decreased cell proliferation and β-catenin protein levels. Apc(+)/Apc(1638N) mice, which develop desmoid tumors, develop smaller and fewer tumors when Hh signaling was inhibited either genetically (by crossing Apc(+)/Apc(1638N) mice with mice lacking one copy of a Hh-activated transcription factor, Gli2 (+/-) mice) or using a pharmacologic inhibitor. Both in mice and in human tumor cell cultures, β-catenin and Hh-mediated signaling positively regulate each other's activity. These data show that targeting a pathway that regulates MSC differentiation influences desmoid tumor behavior, providing functional evidence supporting the notion that these tumors are derived from mesenchymal progenitors. It also suggests Hh blockade as a therapeutic approach for this tumor type.

Related: APC Signal Transduction CTNNB1 gene

Zhao M, Tang SN, Marsh JL, et al.
Ellagic acid inhibits human pancreatic cancer growth in Balb c nude mice.
Cancer Lett. 2013; 337(2):210-7 [PubMed] Related Publications
Ellagic acid (EA) is a polyphenol found in several plants and fruits. The objectives of this study were to examine the molecular mechanisms by which EA inhibits pancreatic cancer growth in Balb C nude mice. PANC-1 cells were injected subcutaneously into Balb c nude mice, and tumor-bearing mice were treated with EA. The expression of Akt, Shh and Notch and their target gene products were measured by the immunohistochemistry and Western blot analysis. Treatment of PANC-1 xenografted mice with EA resulted in significant inhibition in tumor growth which was associated with suppression of cell proliferation and caspase-3 activation, and induction of PARP cleavage. EA inhibited the expression of Bcl-2, cyclin D1, CDK2, and CDK6, and induced the expression of Bax in tumor tissues compared to untreated control group. EA inhibited the markers of angiogenesis (COX-2, HIF1α, VEGF, VEGFR, IL-6 and IL-8), and metastasis (MMP-2 and MMP-9) in tumor tissues. Furthermore, treatment of mice with EA caused a significant inhibition in phospho-Akt, Gli1, Gli2, Notch1, Notch3, and Hey1. EA also reversed epithelial to mesenchymal transition by up-regulating E-cadherin and inhibiting the expression of Snail, MMP-2 and MMP-9. These data suggest that EA can inhibit pancreatic cancer growth, angiogenesis and metastasis by suppressing Akt, Shh and Notch pathways. In view of the fact that EA could effectively inhibit human pancreatic cancer growth by suppressing Akt, Shh and Notch pathways, our findings suggest that the use of EA would be beneficial for the management of pancreatic cancer.

Related: Apoptosis Angiogenesis and Cancer Cancer of the Pancreas Pancreatic Cancer AKT1 Signal Transduction

Lu J, Chen M, Ren XR, et al.
Regulation of hedgehog signaling by Myc-interacting zinc finger protein 1, Miz1.
PLoS One. 2013; 8(5):e63353 [PubMed] Article available free on PMC after 01/01/2015 Related Publications
Smoothened (Smo) mediated Hedgehog (Hh) signaling plays an essential role in regulating embryonic development and postnatal tissue homeostasis. Aberrant activation of the Hh pathway contributes to the formation and progression of various cancers. In vertebrates, however, key regulatory mechanisms responsible for transducing signals from Smo to the nucleus remain to be delineated. Here, we report the identification of Myc-interacting Zinc finger protein 1 (Miz1) as a Smo and Gli2 binding protein that positively regulates Hh signaling. Overexpression of Miz1 increases Gli luciferase reporter activity, whereas knockdown of endogenous Miz1 has the opposite effect. Activation of Smo induces translocation of Miz1 to the primary cilia together with Smo and Gli2. Furthermore, Miz1 is localized to the nucleus upon Hh activation in a Smo-dependent manner, and loss of Miz1 prevents the nuclear translocation of Gli2. More importantly, silencing Miz1 expression inhibits cell proliferation in vitro and the growth of Hh-driven medulloblastoma tumors allografted in SCID mice. Taken together, these results identify Miz1 as a novel regulator in the Hh pathway that plays an important role in mediating Smo-dependent oncogenic signaling.

Related: Childhood Medulloblastoma / PNET Signal Transduction

Ghasemi R, Ghaffari SH, Momeny M, et al.
Multitargeting and antimetastatic potentials of silibinin in human HepG-2 and PLC/PRF/5 hepatoma cells.
Nutr Cancer. 2013; 65(4):590-9 [PubMed] Related Publications
Hepatocellular carcinoma (HCC) is the most common sort of primary liver malignancy with poor prognosis. This study aimed at examining the effects of silibinin (a putative antimetastatic agent) on some transcriptional markers mechanistically related to HCC recurrence and metastasis in HepG-2 [hepatitis B virus (HBV)-negative and P53 intact) and PLC/PRF/5 (HBV-positive and P53 mutated) cells. The expression of 27 genes in response to silibinin was evaluated by real-time RT-PCR. The MMP gelatinolytic assay and microculture tetrazolium test (MTT) were tested. Silibinin was capable of suppressing the transcriptional levels of ANGPT2, ATP6L, CAP2, CCR6, CCR7, CLDN-10, cortactin, CXCR4, GLI2, HK2, ID1, KIAA0101, mortalin, PAK1, RHOA, SPINK1, and STMN1 as well as the enzymatic activity of MMP-2 but promoted the transcripts of CREB3L3, DDX3X, and PROX1 in both cells. Some significant differences between the cells in response to silibinin were detected that might be related to the differences of the cells in terms of HBV infection and/or P53 mutation, suggesting the possible influence of silibinin on HCC through biological functions of these 2 prognostic factors. In conclusion, our findings suggest that silibinin could potentially function as a multitargeting antimetastatic agent and might provide new insights for HCC therapy particularly for HBV-related and/or P53-mutated HCCs.

Related: Liver Cancer MMP2 MMP9: matrix metallopeptidase 9

Ibuki N, Ghaffari M, Pandey M, et al.
TAK-441, a novel investigational smoothened antagonist, delays castration-resistant progression in prostate cancer by disrupting paracrine hedgehog signaling.
Int J Cancer. 2013; 133(8):1955-66 [PubMed] Related Publications
Hedgehog (Hh) signaling is a highly conserved intercellular and intracellular communication mechanism that governs organogenesis and is dysregulated in cancers of numerous tissues, including prostate. Up-regulated expression of the Hh ligands, Sonic (Shh) and Desert (Dhh), has been reported in androgen-deprived and castration-resistant prostate cancer (CRPC). In a cohort of therapy naive, short- and long-term neoadjuvant hormone therapy-treated (NHT), and CRPC specimens, we observed elevated Dhh expression predominantly in long-term NHT specimens and elevated Shh expression predominantly in CRPC specimens. Together with previously demonstrated reciprocal signaling between Shh-producing prostate cancer (PCa) cells and urogenital mesenchymal fibroblasts, these results suggest that castration-induced Hh expression promotes CRPC progression through reciprocal paracrine signaling within the tumor microenvironment. We tested whether the orally available Smoothened (Smo) antagonist, TAK-441, could impair castration-resistant progression of LNCaP PCa xenografts by disrupting paracrine Hh signaling. Although TAK-441 or cyclopamine did not affect androgen withdrawal-induced Shh up-regulation or viability of LNCaP cells, castration-resistant progression of LNCaP xenografts was significantly delayed in animals treated with TAK-441. In TAK-441-treated xenografts, expression of murine orthologs of the Hh-activated genes, Gli1, Gli2 and Ptch1, was substantially suppressed, while expression of the corresponding human orthologs was unaffected. As androgen-deprived LNCaP cells up-regulate Shh expression, but are not sensitive to Smo antagonists, these studies indicate that TAK-441 leads to delayed castration-resistant progression of LNCaP xenografts by disrupting paracrine Hh signaling with the tumor stroma. Thus, paracrine Hh signaling may offer unique opportunities for prognostic biomarker development, drug targeting and therapeutic response monitoring of PCa progression.

Related: Prostate Cancer

Tang L, Tan YX, Jiang BG, et al.
The prognostic significance and therapeutic potential of hedgehog signaling in intrahepatic cholangiocellular carcinoma.
Clin Cancer Res. 2013; 19(8):2014-24 [PubMed] Related Publications
PURPOSE: The correlation of the hedgehog signaling pathway with the progression, prognosis, and therapeutics of intrahepatic cholangiocellular carcinoma (ICC) has not been well documented. The study aimed to investigate the expression, prognostic significance, and therapeutic value of hedgehog components in ICC.
EXPERIMENTAL DESIGN: Two independent cohorts of 200 patients with ICC were enrolled. By real-time PCR and immunohistochemistry assay, hedgehog components expression was evaluated. The prognostic values of hedgehog proteins were identified and verified. Cyclopamine or siRNA-targeting Gli was used to block the hedgehog signaling. Cell proliferation and apoptosis were observed by CCK8, cell cycle, and annexin V staining assays. In vivo murine tumor model was used to evaluate the role of hedgehog in ICC.
RESULTS: In ICC tissues, the Gli1 nuclear immune-intensity was associated with intrahepatic metastasis and the expression of Gli2 was associated with intrahepatic metastasis, venous invasion, and Unio Internationale Contra Cancrum (UICC) pT characteristics. In survival analysis, high Gli1 or Gli2 expressers had an unfavorable overall survival (OS) prognosis and a shorter disease-free survival (DFS) than those with low expression. In multivariate analysis, Gli1 expression was found to be an independent prognostic factor of OS, which was validated by another independent cohort. Furthermore, blocking the hedgehog signaling by cyclopamine or siRNA-targeting Gli1 resulted in apoptosis and growth inhibition in ICC cells.
CONCLUSIONS: This study shows, for the first time, activation of hedgehog pathway associated with the progression and metastasis in ICC, which may provide prognostic and therapeutic values for this tumor.

Related: Apoptosis Extra-Hepatic Bile duct cancer (cholangiocarcinoma) Signal Transduction GLI

Li H, Lui N, Cheng T, et al.
Gli as a novel therapeutic target in malignant pleural mesothelioma.
PLoS One. 2013; 8(3):e57346 [PubMed] Article available free on PMC after 01/01/2015 Related Publications
Malignant pleural mesothelioma (MPM) is a highly aggressive tumor with poor prognosis. Current treatment is rarely curative, thus novel meaningful therapies are urgently needed. Inhibition of Hedgehog (Hh) signaling at the cell membrane level in several cancers has shown anti-cancer activity in recent clinical studies. Evidence of Hh-independent Gli activation suggests Gli as a more potent therapeutic target. The current study is aimed to evaluate the potential of Gli as a therapeutic target to treat MPM. The expression profiles of Gli factors and other Hh signaling components were characterized in 46 MPM patient tissue samples by RT-PCR and immunohistochemistry. Cultured cell lines were employed to investigate the requirement of Gli activation in tumor cell growth by inhibiting Gli through siRNA or a novel small molecule Gli inhibitor (Gli-I). A xenograft model was used to evaluate Gli-I in vivo. In addition, a side by side comparison between Gli and Smoothened (Smo) inhibition was conducted in vitro using siRNA and small molecule inhibitors. Our study reported aberrant Gli1 and Gli2 activation in a large majority of tissues. Inhibition of Gli by siRNAs or Gli-I suppressed cell growth dramatically both in vitro and in vivo. Inhibition of Gli exhibited better cytotoxicity than that of Smo by siRNA and small molecule inhibitors vismodegib and cyclopamine. Combination of Gli-I and pemetrexed, as well as Gli-I and vismodegib demonstrated synergistic effects in suppression of MPM proliferation in vitro. In summary, Gli activation plays a critical role in MPM. Inhibition of Gli function holds strong potential to become a novel, clinically effective approach to treat MPM.

Related: Mesothelioma Signal Transduction GLI Pemetrexed

Fu J, Rodova M, Nanta R, et al.
NPV-LDE-225 (Erismodegib) inhibits epithelial mesenchymal transition and self-renewal of glioblastoma initiating cells by regulating miR-21, miR-128, and miR-200.
Neuro Oncol. 2013; 15(6):691-706 [PubMed] Article available free on PMC after 01/01/2015 Related Publications
BACKGROUND: Glioblastoma multiforme is the most common form of primary brain tumor, often characterized by poor survival. Glioblastoma initiating cells (GICs) regulate self-renewal, differentiation, and tumor initiation properties and are involved in tumor growth, recurrence, and resistance to conventional treatments. The sonic hedgehog (SHH) signaling pathway is essential for normal development and embryonic morphogenesis. The objectives of this study were to examine the molecular mechanisms by which GIC characteristics are regulated by NPV-LDE-225 (Smoothened inhibitor; (2,2'-[[dihydro-2-(4-pyridinyl)-1,3(2H,4H)-pyrimidinediyl]bis(methylene)]bis[N,N-dimethylbenzenamine).
METHODS: Cell viability and apoptosis were measured by XTT and annexin V-propidium iodide assay, respectively. Gli translocation and transcriptional activities were measured by immunofluorescence and luciferase assay, respectively. Gene and protein expressions were measured by quantitative real-time PCR and Western blot analyses, respectively.
RESULTS AND CONCLUSION: NPV-LDE-225 inhibited cell viability, neurosphere formation, and Gli transcriptional activity and induced apoptosis by activation of caspase-3 and cleavage of poly(ADP-ribose) polymerase. NPV-LDE-225 increased the expression of tumor necrosis factor-related apoptosis inducing ligand (TRAIL)-R1/DR4, TRAIL-R2/DR5, and Fas and decreased the expression of platelet derived growth factor receptor-α and Bcl2, and these effects were abrogated by Gli1 plus Gli2 short hairpin RNAs. NPV-LDE-225 enhanced the therapeutic potential of FasL and TRAIL by upregulating Fas and DR4/5, respectively. Interestingly, NPV-LDE-225 induced expression of programmed cell death 4 and apoptosis and inhibited cell viability by suppressing micro RNA (miR)-21. Furthermore, NPV-LDE-225 inhibited pluripotency-maintaining factors Nanog, Oct4, Sox2, and cMyc. The inhibition of Bmi1 by NPV-LDE-225 was regulated by induction of miR-128. Finally, NPV-LDE-225 suppressed epithelial-mesenchymal transition by upregulating E-cadherin and inhibiting N-cadherin, Snail, Slug, and Zeb1 through modulating the miR-200 family. Our data highlight the importance of the SHH pathway for self-renewal and early metastasis of GICs.

Related: Apoptosis CASP3 Signal Transduction GLI miR-21

Barakat MT, Humke EW, Scott MP
Kif3a is necessary for initiation and maintenance of medulloblastoma.
Carcinogenesis. 2013; 34(6):1382-92 [PubMed] Article available free on PMC after 01/01/2015 Related Publications
Medulloblastoma (MB) cells arise from granule neuron precursors (GNPs) that have lost growth control. During normal development, GNPs divide in response to Sonic hedgehog (SHH), a ligand that binds to the patched (PTCH) receptor on GNPs. If one copy of the Ptch gene is lost, as in human Gorlin's syndrome and in Ptch(+/-) mice, MBs may form. Proper transduction of the SHH signal critically depends on primary cilia. Loss of primary cilia results in improper signal reception and failure to properly activate SHH target genes. KIF3a, part of a kinesin motor, is required for formation of primary cilia. Here, we use tamoxifen-induced ablation of Kif3a in GNPs of postnatal Ptch(+/-) mouse cerebella to show that KIF3a is necessary for MB formation. To investigate the importance of primary cilia in established tumors, we deleted Kif3a from cultured cells and from tumor cell grafts. The loss of Kif3a from established tumors led to their growth arrest and regression. MBs behave as if they are addicted to the presence of primary cilia. These results underscore the potential utility of agents that disrupt cilia for the treatment of Hh pathway-related MBs.

Related: Childhood Medulloblastoma / PNET

Lee SJ, Do IG, Lee J, et al.
Gastric cancer (GC) patients with hedgehog pathway activation: PTCH1 and GLI2 as independent prognostic factors.
Target Oncol. 2013; 8(4):271-80 [PubMed] Related Publications
Activation of sonic hedgehog (HH) signaling pathway has been implicated in aggressiveness and progression of gastrointestinal tumors. We planned this study to identify a subgroup of gastric cancer (GC) patients with HH activation and to assess the effect of a HH inhibitor in HH activated GC in vitro. We surveyed HH pathway activation among 512 GC specimens for protein expression of various target genes involved in HH pathway: Indian hedgehog (IHH), patched-1 (PTCH1), smoothened (SMO), GLI2, and FOXA2. We analyzed the correlations between the expression of these factors and clinicopathological features and prognosis. In vitro, ten gastric cancer cell lines were screened for anti-tumoractivity of an HH inhibitor, GDC-0449. Among the 512 specimens, 105 (20.0 %), 83 (16.3 %), 130 (25.5 %), 61 (12.0 %), and 206 (40.8 %) were positive for IHH, PTCH1, GLI2, SMO, and FOXA2 expression, respectively. PTCH1 expression was more frequently observed in well- or moderately differentiated tubular adenocarcinoma, intestinal type and low stage GC. GLI2 was correlated with lymphovascular invasion and intestinal type GC. A high-stage and negative PTCH1 staining were identified as unfavorable independent risk factors for overall survival in multivariate analysis (P < 0.001, 0.045, respectively). For IHH, SMO, and FOXA2, there was no statistical difference in clinicopathologic variables and survival outcome. An HH inhibitor had particularly potent effects on GC cell lines with SMO mRNA overexpression. This is the largest report to analyze the hedgehog pathway in GC. PTCH1 overexpression was an independent prognostic factor for survival and SMO overexpression which was found in 12.0 % of GC patients might be the potential predictive marker of HH inhibitor.

Related: Signal Transduction Stomach Cancer Gastric Cancer

Gopinath S, Malla R, Alapati K, et al.
Cathepsin B and uPAR regulate self-renewal of glioma-initiating cells through GLI-regulated Sox2 and Bmi1 expression.
Carcinogenesis. 2013; 34(3):550-9 [PubMed] Article available free on PMC after 01/01/2015 Related Publications
Cancer-initiating cells comprise a heterogeneous population of undifferentiated cells with the capacity for self-renewal and high proliferative potential. We investigated the role of uPAR and cathepsin B in the maintenance of stem cell nature in glioma-initiating cells (GICs). Simultaneous knockdown of uPAR and cathepsin B significantly reduced the expression of CD133, Nestin, Sox2 and Bmi1 at the protein level and GLI1 and GLI2 at the messenger RNA level. Also, knockdown of uPAR and cathepsin B resulted in a reduction in the number of GICs as well as sphere size. These changes are mediated by Sox2 and Bmi1, downstream of hedgehog signaling. Addition of cyclopamine reduced the expression of Sox2 and Bmi1 along with GLI1 and GLI2 expression, induced differentiation and reduced subsphere formation of GICs thereby indicating that hedgehog signaling acts upstream of Sox2 and Bmi1. Further confirmation was obtained from increased luciferase expression under the control of a GLI-bound Sox2 and Bmi1 luciferase promoter. Simultaneous knockdown of uPAR and cathepsin B also reduced the expression of Nestin Sox2 and Bmi1 in vivo. Thus, our study highlights the importance of uPAR and cathepsin B in the regulation of malignant stem cell self-renewal through hedgehog components, Bmi1 and Sox2.

Related: Signal Transduction GLI SOX2 gene

Fu J, Rodova M, Roy SK, et al.
GANT-61 inhibits pancreatic cancer stem cell growth in vitro and in NOD/SCID/IL2R gamma null mice xenograft.
Cancer Lett. 2013; 330(1):22-32 [PubMed] Article available free on PMC after 01/01/2015 Related Publications
Multiple lines of evidence suggest that the Sonic Hedgehog (Shh) signaling pathway is aberrantly reactivated in pancreatic cancer stem cells (CSCs). The objectives of this study were to examine the molecular mechanisms by which GANT-61 (Gli transcription factor inhibitor) regulates stem cell characteristics and tumor growth. Effects of GANT-61 on CSC's viability, spheroid formation, apoptosis, DNA-binding and transcriptional activities, and epithelial-mesenchymal transition (EMT) were measured. Humanized NOD/SCID/IL2R gamma(null) mice were used to examine the effects of GANT-61 on CSC's tumor growth. GANT-61 inhibited cell viability, spheroid formation, and Gli-DNA binding and transcriptional activities, and induced apoptosis by activation of caspase-3 and cleavage of Poly-ADP ribose Polymerase (PARP). GANT-61 increased the expression of TRAIL-R1/DR4, TRAIL-R2/DR5 and Fas, and decreased expression of PDGFRα and Bcl-2. GANT-61 also suppressed EMT by up-regulating E-cadherin and inhibiting N-cadherin and transcription factors Snail, Slug and Zeb1. In addition, GANT-61 inhibited pluripotency maintaining factors Nanog, Oct4, Sox-2 and cMyc. Suppression of both Gli1 plus Gli2 by shRNA mimicked the changes in cell viability, spheroid formation, apoptosis and gene expression observed in GANT-61-treated pancreatic CSCs. Furthermore, GANT-61 inhibited CSC tumor growth which was associated with up-regulation of DR4 and DR5 expression, and suppression of Gli1, Gli2, Bcl-2, CCND2 and Zeb1 expression in tumor tissues derived from NOD/SCID IL2Rγ null mice. Our data highlight the importance of Shh pathway for self-renewal and metastasis of pancreatic CSCs, and also suggest Gli as a therapeutic target for pancreatic cancer in eliminating CSCs.

Related: Apoptosis Cancer of the Pancreas Pancreatic Cancer Signal Transduction GLI


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Cite this page: Cotterill SJ. GLI2, Cancer Genetics Web: http://www.cancerindex.org/geneweb/GLI2.htm Accessed: date

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