Research IndicatorsGraph generated 27 February 2015 using data from PubMed using criteria.
Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic. Tag cloud generated 27 February, 2015 using data from PubMed, MeSH and CancerIndex
Specific Cancers (7)
Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.
Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).
OMIM, Johns Hopkin University
Referenced article focusing on the relationship between phenotype and genotype.
International Cancer Genome Consortium.
Summary of gene and mutations by cancer type from ICGC
Cancer Genome Anatomy Project, NCI
COSMIC, Sanger Institute
Somatic mutation information and related details
Search the Epigenomics database and view relevant gene tracks of samples.
Latest Publications: SUFU (cancer-related)
Smith MJ, Beetz C, Williams SG, et al.Germline mutations in SUFU cause Gorlin syndrome-associated childhood medulloblastoma and redefine the risk associated with PTCH1 mutations.
J Clin Oncol. 2014; 32(36):4155-61 [PubMed
] Related Publications
PURPOSE: Heterozygous germline PTCH1 mutations are causative of Gorlin syndrome (naevoid basal cell carcinoma), but detection rates > 70% have rarely been reported. We aimed to define the causative mutations in individuals with Gorlin syndrome without PTCH1 mutations.
METHODS: We undertook exome sequencing on lymphocyte DNA from four unrelated individuals from families with Gorlin syndrome with no PTCH1 mutations found by Sanger sequencing, multiplex ligation-dependent probe amplification (MLPA), or RNA analysis.
RESULTS: A germline heterozygous nonsense mutation in SUFU was identified in one of four exomes. Sanger sequencing of SUFU in 23 additional PTCH1-negative Gorlin syndrome families identified a SUFU mutation in a second family. Copy-number analysis of SUFU by MLPA revealed a large heterozygous deletion in a third family. All three SUFU-positive families fulfilled diagnostic criteria for Gorlin syndrome, although none had odontogenic jaw keratocysts. Each SUFU-positive family included a single case of medulloblastoma, whereas only two (1.7%) of 115 individuals with Gorlin syndrome and a PTCH1 mutation developed medulloblastoma.
CONCLUSION: We demonstrate convincing evidence that SUFU mutations can cause classical Gorlin syndrome. Our study redefines the risk of medulloblastoma in Gorlin syndrome, dependent on the underlying causative gene. Previous reports have found a 5% risk of medulloblastoma in Gorlin syndrome. We found a < 2% risk in PTCH1 mutation-positive individuals, with a risk up to 20× higher in SUFU mutation-positive individuals. Our data suggest childhood brain magnetic resonance imaging surveillance is justified in SUFU-related, but not PTCH1-related, Gorlin syndrome.
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.
Szczepny A, Wagstaff KM, Dias M, et al.Overlapping binding sites for importin β1 and suppressor of fused (SuFu) on glioma-associated oncogene homologue 1 (Gli1) regulate its nuclear localization.
Biochem J. 2014; 461(3):469-76 [PubMed
] Related Publications
A key factor in oncogenesis is the transport into the nucleus of oncogenic signalling molecules, such as Gli1 (glioma-associated oncogene homologue 1), the central transcriptional activator in the Hedgehog signalling pathway. Little is known, however, how factors such as Gli are transported into the nucleus and how this may be regulated by interaction with other cellular factors, such as the negative regulator suppressor of fused (SuFu). In the present study we show for the first time that nuclear entry of Gli1 is regulated by a unique mechanism through mutually exclusive binding by its nuclear import factor Impβ1 (importin β1) and SuFu. Using quantitative live mammalian cell imaging, we show that nuclear accumulation of GFP-Gli1 fusion proteins, but not of a control protein, is specifically inhibited by co-expression of SuFu. Using a direct binding assay, we show that Impβ1 exhibits a high nanomolar affinity to Gli1, with specific knockdown of Impβ1 expression being able to inhibit Gli1 nuclear accumulation, thus implicating Impβ1 as the nuclear transporter for Gli1 for the first time. SuFu also binds to Gli1 with a high nanomolar affinity, intriguingly being able to compete with Impβ1 for binding to Gli1, through the fact that the sites for SuFu and Impβ1 binding overlap at the Gli1 N-terminus. The results indicate for the first time that the relative intracellular concentrations of SuFu and Impβ1 are likely to determine the localization of Gli1, with implications for its action in cancer, as well as in developmental systems.
Gomes DC, Leal LF, Mermejo LM, et al.Sonic hedgehog signaling is active in human adrenal cortex development and deregulated in adrenocortical tumors.
J Clin Endocrinol Metab. 2014; 99(7):E1209-16 [PubMed
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BACKGROUND: The sonic hedgehog (SHH) pathway plays a key role in rodent adrenal cortex development and is involved in tumorigenesis in several human tissues, but data in human adrenal glands are limited.
OBJECTIVES: The objectives of the study were to analyze the involvement of the SHH pathway in human adrenal development and tumorigenesis and the effects of SHH inhibition on an adrenocortical tumor (ACT) cell line.
PATIENTS AND METHODS: Expression of SHH pathway components was evaluated by immunohistochemistry in 51 normal adrenals (33 fetal) and 34 ACTs (23 pediatric) and by quantitative PCR in 81 ACTs (61 pediatric) and 19 controls (10 pediatric). The effects of SHH pathway inhibition on gene expression and cell viability in the NCI-H295A adrenocortical tumor cell line after cyclopamine treatment were analyzed.
RESULTS: SHH pathway proteins were present in fetal and postnatal normal adrenals and showed distinct patterns of spatiotemporal expression throughout development. Adult adrenocortical carcinomas presented with higher expression of PTCH1, SMO, GLI3, and SUFU compared with normal adult adrenal cortices. Conversely, pediatric ACTs showed lower mRNA expression of SHH, PTCH1, SMO, GLI1, and GLI3 compared with normal pediatric adrenal cortices. In vitro treatment with cyclopamine resulted in decreased GLI3, SFRP1, and CTNNB1 mRNA expression and β-catenin staining as well as decreased cell viability.
CONCLUSIONS: The SHH pathway is active in human fetal and postnatal adrenals, up-regulated in adult adrenocortical carcinomas, and down-regulated in pediatric ACTs. SHH pathway antagonism impaired cell viability. The SHH pathway is deregulated in ACTs and might provide a new target therapy to be explored.
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.
Subbiah V, Westin SN, Wang K, et al.Targeted therapy by combined inhibition of the RAF and mTOR kinases in malignant spindle cell neoplasm harboring the KIAA1549-BRAF fusion protein.
J Hematol Oncol. 2014; 7(1):8 [PubMed
] Free Access to Full Article Related Publications
BACKGROUND: Oncologic patients who are extreme responders to molecularly targeted therapy provide an important opportunity to better understand the biologic basis of response and, in turn, inform clinical decision making. Malignant neoplasms with an uncertain histologic and immunohistochemical characterization present challenges both on initial diagnostic workups and then later in management, as current treatment algorithms are based on a morphologic diagnosis. Herein, we report a case of a difficult to characterize sarcoma-like lesion for which genomic profiling with clinical next generation sequencing (NGS) identified the molecular underpinnings of arrested progression(stable disease) under combination targeted therapy within a phase I clinical trial.
METHODS: Genomic profiling with clinical next generation sequencing was performed on the FoundationOne™ platform (Foundation Medicine, Cambridge MA). Histopathology and immunohistochemical studies were performed in the Department of Pathology, MD Anderson Cancer Center (Houston, TX). Treatment was administered in the context of a phase I clinical trial ClinicalTrials.gov Identifier: (NCT01187199).
RESULTS: The histology of the tumor was that of a spindle cell neoplasm, grade 2 by FNCLCC standards. Immunohistochemical staining was positive for S100 and CD34. Genomic profiling identified the following alterations: a KIAA1549-BRAF gene fusion resulting from a tandem duplication event, a homozygous deletion of PTEN, and frameshift insertion/deletions in CDKN2A A68fs*51, SUFU E283fs*3, and MAP3K1 N325fs*3. The patient had a 25% reduction in tumor (RECIST v1.1) following combination therapy consisting of sorafenib, temsirolimus, and bevazicumab within a phase I clinical trial.
CONCLUSIONS: The patient responded to combination targeted therapy that fortuitously targeted KIAA1549-BRAF and PTEN loss within a spindle cell neoplasm, as revealed by genomic profiling based on NGS. This is the first report of a tumor driven by a KIAA1549-BRAF fusion responding to sorafenib-based combination therapy.
Bourdeaut F, Miquel C, Richer W, et al.Rubinstein-Taybi syndrome predisposing to non-WNT, non-SHH, group 3 medulloblastoma.
Pediatr Blood Cancer. 2014; 61(2):383-6 [PubMed
] Related Publications
Medulloblastomas (MB) are classified in four subgroups: the well defined WNT and Sonic Hedgehog (SHH) subgroups, and the less defined groups 3 and 4. They occasionally occur in the context of a cancer predisposition syndrome. While germline APC mutations predispose to WNT MB, germline mutations in SUFU, PTCH1, and TP53 predispose to SHH tumors. We report on a child with a Rubinstein-Taybi syndrome (RTS) due to a germline deletion in CREBBP, who developed a MB. Biological profilings demonstrate that this tumor belongs to the group 3. RTS may therefore be the first predisposition syndrome identified for non-WNT/non-SHH MB.
Yan R, Peng X, Yuan X, et al.Suppression of growth and migration by blocking the Hedgehog signaling pathway in gastric cancer cells.
Cell Oncol (Dordr). 2013; 36(5):421-35 [PubMed
] Related Publications
PURPOSE: Previous studies have indicated that Hedgehog signaling is essential for gastric cancer development, but its precise role is still unclear. The aim of this study was to clarify the role of Hedgehog signaling in gastric cancer development.
METHODS: The expression of key Hedgehog signaling components in clinical samples of sequential gastric cancer stages was assessed by immunohistochemistry. The roles and regulatory mechanisms of Hedgehog signaling in human gastric cancer cells and normal gastric epithelial cells were investigated using multiple cell biological approaches and cDNA microarray analyses.
RESULTS: Hedgehog signaling was found to be abnormally activated in a ligand-independent manner during gastric cancer development. Gli1 over-expression and reduced SuFu expression were found to be typical events in gastric cancer tissues. Gli1 over-expression was found to correlate with a poorly differentiated histology, advanced clinical stage, membrane serosa infiltration and lymph node metastasis in patients with gastric cancer. Data obtained from multiple cell biological assays showed that human gastric cancer cells require active Hedgehog signaling for survival, proliferation, migration and colony formation. N-Shh treatment significantly enhanced the migration, invasion and colony formation of gastric cancer cells. Moreover, the results of cDNA microarray analyses indicated that after treatment with cyclopamine or GANT61 (inhibitors of Hedgehog signaling), differentially expressed genes in gastric cancer cells were enriched in the apoptosis and MAPK pathways. Inhibitors of the Hedgehog pathway were found to suppress gastric cancer cell growth via apoptosis induction.
CONCLUSIONS: Our findings indicate a vital role of the activated Hedgehog signaling pathway in promoting gastric initiation and progression. The Hedgehog signaling pathway may serve as a target for gastric cancer therapy.
Suzuki M, Nagao K, Hatsuse H, et al.Molecular pathogenesis of keratocystic odontogenic tumors developing in nevoid basal cell carcinoma syndrome.
Oral Surg Oral Med Oral Pathol Oral Radiol. 2013; 116(3):348-53 [PubMed
] Related Publications
OBJECTIVE: The aim of this study was to investigate the molecular pathogenesis of keratocystic odontogenic tumors (KCOTs) that developed in nevoid basal cell carcinoma syndrome (NBCCS) patients.
STUDY DESIGN: We analyzed germline and somatic mutations of the PTCH1 and its related genes, SMO and SUFU in 10 KCOTs that developed in 8 unrelated NBCCS patients. Methylation status of the PTCH1 promoter was also investigated by bisulfite sequencing.
RESULTS: Somatic mutations of PTCH1 were detected in 3 KCOTs. Two out of 3 somatic mutations were either identified as a polymorphism or located on the same allele as the germline mutation. Neither abnormal methylation of the PTCH1 promoter, loss of PTCH1, nor somatic mutation of SMO or SUFU was detected in any of the samples.
CONCLUSIONS: Our results suggest that the tumorigenesis of most KCOTs associated with NBCCS cannot be explained by the classical 2-hit theory.
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
] Free Access to Full Article 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.
Activation of the Hedgehog (Hh) signaling pathway has been implicated in a variety of malignancies including neuroblastoma. Expression of Gli1, a downstream effector of Hh, correlates with a favorable prognosis in patients with neuroblastoma. Moreover, Gli1 overexpression reduces mitotic index and induces transcription of genes involved in the differentiation of neuroblastoma cells; however, much remains unknown regarding the regulation of Gli1 transcriptional activity. Here, we report a novel negative regulation of Gli1 transcriptional activity by PI3K/AKT2 signal transduction pathway. Constitutively active PI3K subunit, p110α, inhibited Gli1 transcriptional activity in neuroblastoma cells, whereas, overexpression of an inactive form of PI3K subunit, p85, enhanced its activity. Specifically, the AKT2 isoform inhibited Gli1 luciferase activity. Silencing AKT2 using siRNA increased Gli1 transcriptional activity and conversely, overexpression of constitutively active AKT2 (myr-AKT2) decreased Gli1 transcriptional activity. Furthermore, Gli1 overexpression-mediated decrease in anchorage-independent growth was rescued by AKT2 overexpression. We also demonstrated that AKT2 overexpression regulates the nuclear-cytoplasmic distribution of exogenous Gli1 protein in neuroblastoma cells by relieving a GSK3β-mediated destabilization of SUFU, a negative regulator of Gli1 nuclear translocation. Inhibition of nuclear Gli1 accumulation may explain for the suppression of the tumor-suppressive function of Gli1. Collectively, our findings suggest an important role of Gli1 as a tumor suppressor in neuroblastoma, and offer a mechanism by which AKT2 regulates the subcellular localization, and in turn, inhibits the tumor-suppressive function of Gli1 in neuroblastoma.
Constitutive activation of the Hedgehog (Hh) signaling pathway has been implicated in the development of many human malignancies. Hh targets, such as Patched (PTCH), smoothened (SMO), Sonic hedgehog (SHH) and glioma-associated oncogene homologue 1 (GLI1), are markers of Hh signaling activation and expressed in most Hh-associated tumors. The protein kinase LKB1 has been shown to slow proliferation and induce cell-cycle arrest in many cell lines. In this study, we observed that activated LKB1 decreased the expression of factors related to Hh reporter activity in MDA-MB-231 breast cancer cells, including of SMO, SHH and GLI1. In contrast, LKB1 siRNA increased the expression of these target genes. The same results were shown to inhibit the Hh factors Sufu and Hip. Furthermore, we also observed negative correlation between LKB1 and glioma-associated oncogene homologue 1 (GLI1) in three breast cancer cell lines. Meanwhile, LKB1 siRNA rescued the inhibition of cell growth by 3-Keto-N-(aminoethyl-N'-aminocaproyldihydrocinnamoyl) cyclopamine (KAAD-cyclopamine), an antagonist of the Hh element SMO, which suggests that LKB1 acts as the downstream of SMO. In vivo, LKB1 siRNA increased tumor growth in the mammary fat pad, and the expression levels of Hh displayed similar results in vitro. Overexpression of the LKB1 protein in human breast cancers is associated with the expression of Hh. We found that breast carcinomas with detectable Hh had weak or undetectable expression of LKB1, whereas tumors that expressed high levels of LKB1 had undetectable Hh signaling. In this study, we find that LKB1 are negatively correlated with the expression of Hh related transcription factors. These findings suggest that LKB1 may inhibit tumorigenesis by regulating Hh signaling in certain cancers.
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.
Adenoid cystic carcinoma (ACC) is a rare malignancy that can occur in multiple organ sites and is primarily found in the salivary gland. While the identification of recurrent fusions of the MYB-NFIB genes have begun to shed light on the molecular underpinnings, little else is known about the molecular genetics of this frequently fatal cancer. We have undertaken exome sequencing in a series of 24 ACC to further delineate the genetics of the disease. We identified multiple mutated genes that, combined, implicate chromatin deregulation in half of cases. Further, mutations were identified in known cancer genes, including PIK3CA, ATM, CDKN2A, SF3B1, SUFU, TSC1, and CYLD. Mutations in NOTCH1/2 were identified in 3 cases, and we identify the negative NOTCH signaling regulator, SPEN, as a new cancer gene in ACC with mutations in 5 cases. Finally, the identification of 3 likely activating mutations in the tyrosine kinase receptor FGFR2, analogous to those reported in ovarian and endometrial carcinoma, point to potential therapeutic avenues for a subset of cases.
Li ZJ, Mack SC, Mak TH, et al.Evasion of p53 and G2/M checkpoints are characteristic of Hh-driven basal cell carcinoma.
Oncogene. 2014; 33(20):2674-80 [PubMed
] Related Publications
Basal cell carcinoma (BCC), the most common type of cancer, is characterized by aberrant Hedgehog (Hh) pathway activity. Mutations in pathway components, such as PATCHED1 (PTCH1), are commonly found in BCC. While the tumor suppressor role of PTCH1 in BCC is well established, how Hh pathway activation disrupts normal skin homeostasis to promote BCC formationremains poorly understood. Like Ptc1, Sufu is a major negative regulator of the Hh pathway. Previously, we showed that inactivation of Sufu in the skin does not result in BCC formation. Why loss of Ptc1, but not Sufu, in the epidermis induces BCC formation is unclear. In this report, we utilized gene expression profiling to identify biological pathways and processes that distinguish Sufu from Ptc1 mutants, and discovered a novel role for Sufu in cell cycle regulation. We demonstrated that the Hh pathway activation inSufu and Ptc1 mutant skin is associated with abnormal cell cycle entry, ectopic expression of D-type cyclins and increasedDNA damage. However, despite the presence of DNA damage, p53 stabilization was impaired in the mutant skin. Alternative mechanism to halt genomic instability is the activation of G2/M cell cycle checkpoint, which can occur independent of p53. We found that while Ptc1 mutant cells continue to cycle, which would favor genomic instability, loss of Sufu results in G2/M cell cycle arrest.This finding may explain why inactivation of Sufu is not sufficient to drive BCC formation. Taken together, these studies revealed a unique role for Sufu in G2/M phase progression, and uncovered the molecular and cellular features associated with Hh-driven BCC.
Wang ZC, Gao J, Zi SM, et al.Aberrant expression of sonic hedgehog pathway in colon cancer and melanosis coli.
J Dig Dis. 2013; 14(8):417-24 [PubMed
] Related Publications
OBJECTIVE: To determine the hedgehog (Hh) signaling pathway correlated with the development of colon cancer and melanosis coli.
METHODS: Protein and mRNA levels of Hh signaling pathway components (sonic hedgehog [Shh], protein patched homolog 1 [Ptch 1], GLI family zinc finger 1 [Gli 1] and suppressor of fused homolog [Drosophila] [Sufu]) in 127 patients with colon cancer, 36 with melanosis coli and 20 adjacent normal mucosal tissues taken from surgical specimens were evaluated using antibody staining and quantitative real-time polymerase chain reaction.
RESULTS: In adjacent normal tissue Shh and Ptch1, but not Gli1 or Sufu, were weakly expressed and mainly in the lining epithelium of the colonic mucosa. In cancerous tissues Shh and Gli1 were uniformly strong while Ptch1 was patchy and weak, and Sufu uniformly weak, which paralleled their levels of corresponding mRNA. Elevated protein levels of Shh and Ptch were significantly associated with mucinous colonic tissues. Elevated Sufu protein levels were positively correlated with the diameter and invasion of the tumor. In patients with melanosis coli, mRNA levels of Shh, Ptch1, Gli1 and Sufu were very low, which was similar to those of adjacent normal tissues; but protein levels of Shh, Ptch1 and Gli1, but not Sufu, were high, which was similar to those of cancerous tissues.
CONCLUSIONS: The mRNA and protein levels of Hh pathway components are aberrantly elevated in colon cancer, which may be the potential molecular classification markers. Further studies are required to determine the role of melanosis coli in the colon tumorigenesis.
Yoon JW, Gallant M, Lamm ML, et al.Noncanonical regulation of the Hedgehog mediator GLI1 by c-MYC in Burkitt lymphoma.
Mol Cancer Res. 2013; 11(6):604-15 [PubMed
] Related Publications
Although Hedgehog signaling plays a major role in GLI1 transcription, there is now evidence suggesting that other pathways/genes, such as c-MYC, may also regulate GLI1 expression. We initiated studies in Burkitt lymphoma cells, which constitutively express c-MYC due to a chromosomal translocation, to determine whether Hedgehog or c-MYC regulates GLI1 expression. We show that all Burkitt lymphoma cell lines tested express GLI1, PTCH1, and SMO and that five of six Burkitt lymphomas express GLI1. Exposure to Sonic or Indian Hedgehog or cyclopamine (SMO inhibitor) does not modulate GLI1 expression, cell proliferation, or apoptosis in most Burkitt lymphoma cell lines. Sequence analysis of PTCH1, SMO, and SuFu failed to show mutations that might explain the lack of Hedgehog responsiveness, and we did not detect primary cilia, which may contribute to it. We show that c-MYC interacts with the 5'-regulatory region of GLI1, using chromatin immunoprecipitation (ChIP) assay, and E-box-dependent transcriptional activation of GLI1 by c-MYC in NIH3T3 and HeLa cells. The c-MYC small-molecule inhibitor 10058-F4 downregulates GLI1 mRNA and protein and reduces the viability of Burkitt lymphoma cells. Inhibition of GLI1 by GANT61 increases apoptosis and reduces viability of some Burkitt lymphoma cells. Collectively, our data provide evidence that c-MYC directly regulates GLI1 and support an antiapoptotic role for GLI1 in Burkitt lymphoma. Burkitt lymphoma cells do not seem to be Hedgehog responsive. These findings suggest a mechanism for resistance to SMO inhibitors and have implications for using SMO inhibitors to treat human cancers.
Melanoma is one of the most aggressive skin cancers due to its high capacity to metastasize. Treatment of metastatic melanomas is challenging for clinicians, as most therapeutic agents have failed to demonstrate improved survival. Thus, new candidates with antimetastatic activity are much needed. Riboavin (RF) is a component of the vitamin B complex and a potent photosensitizer. Previously, our group showed that the RF photoproducts (iRF) have potential as an antitumoral agent. Hence, we investigated the capacity of iRF on modulating melanoma B16F10 cells aggressiveness in vitro and in vivo. iRF decreases B16F10 cells survival by inhibiting mTOR as well as Src kinase. Moreover, melanoma cell migration was disrupted after treatment with iRF, mainly by inhibition of metalloproteinase (MMP) activity and expression, and by increasing TIMP expression. Interestingly, we observed that the Hedgehog (HH) pathway was inhibited by iRF. Two mediators of HH signaling, GLI1 and PTCH, were downregulated, while SUFU expression (an inhibitor of this cascade) was enhanced. Furthermore, inhibition of HH pathway signaling by cyclopamine and Gant 61 potentiated the antiproliferative action of RF. Accordingly, when a HH ligand was applied, the effect of iRF was almost completely abrogated. Our findings indicate that Hedgehog pathway is involved on the modulation of melanoma cell aggressiveness by iRF. Moreover, iRF treatment decreased pulmonary tumor formation in a murine experimental metastasis model. Research to clarify the molecular action of flavins, in vivo, is currently in progress. Taken together, the present data provides evidence that riboflavin photoproducts may provide potential candidates for improving the efficiency of melanoma treatment.
Li ZJ, Nieuwenhuis E, Nien W, et al.Kif7 regulates Gli2 through Sufu-dependent and -independent functions during skin development and tumorigenesis.
Development. 2012; 139(22):4152-61 [PubMed
] Related Publications
Abnormal activation of Hedgehog (Hh) signaling leads to basal cell carcinoma (BCC) of the skin, the most common human cancer. Gli2, the major transcriptional activator of Hh signaling, is essential for hair follicle development and its overexpression in epidermis induces BCC formation and maintains tumor growth. Despite its importance in skin development and tumorigenesis, little is known about the molecular regulation of Gli2. Sufu and Kif7 are two evolutionarily conserved regulators of Gli transcription factors. Here, we show that Sufu and Kif7 regulate Gli2 through distinct mechanisms in keratinocytes. Sufu restricts the activity of Gli2 through cytoplasmic sequestration. Kif7 possesses Sufu-dependent and -independent regulatory functions in Hh signaling: while it promotes Hh pathway activity through the dissociation of Sufu-Gli2 complex, it also contributes to the repression of Hh target genes in the absence of Sufu. Deletion of both Sufu and Kif7 in embryonic skin leads to complete loss of follicular fate. Importantly, although inactivation of Sufu or Kif7 alone in adult epidermis cannot promote BCC formation, their simultaneous deletion induces BCC. These studies establish Sufu and Kif7 as crucial components in the regulation of Gli2 localization and activity, and illustrate their overlapping functions in skin development and tumor suppression.
Shahi MH, Rey JA, Castresana JSThe sonic hedgehog-GLI1 signaling pathway in brain tumor development.
Expert Opin Ther Targets. 2012; 16(12):1227-38 [PubMed
] Related Publications
INTRODUCTION: The sonic hedgehog (Shh) pathway is a regulatory network involved in development and cancer. Proteins like Ptch, SMO, and Gli are central to the Shh pathway. Other proteins like HHIP, SUFU, Bmi-1, Cyclin D2, Plakoglobin, PAX6, Nkx2.2, and SFRP1 are not so well understood in Shh regulation as Gli-1 downstream target genes.
AREAS COVERED: In this review we try to explain the Shh pathway components and their role in development and cancer, mainly of the brain. A summary of each of the proteins is presented together with an overview of their involvement in cancer.
EXPERT OPINION: Genetic alterations of the Shh pathway have been detected in cancer stem cells, a subgroup of tumor cells implicated in the origin and maintenance of tumors, being responsible for cancer recurrence and chemotherapy resistance. Cancer stem cells constitute a novel target for biomedical researchers. Specifically, the Shh pathway is being explored as a new opportunity for targeted therapies against tumors. Therefore, a better knowledge of every of the regulators of the Shh pathway is needed.
Meningiomas are the most common primary tumors of the CNS and account for up to 30% of all CNS tumors. An increased risk of meningiomas has been associated with certain tumor-susceptibility syndromes, especially neurofibromatosis type II, but no gene defects predisposing to isolated familial meningiomas have thus far been identified. Here, we report on a family of five meningioma-affected siblings, four of whom have multiple tumors. No NF2 mutations were identified in the germline or tumors. We combined genome-wide linkage analysis and exome sequencing, and we identified in suppressor of fused homolog (Drosophila), SUFU, a c.367C>T (p.Arg123Cys) mutation segregating with the meningiomas in the family. The variation was not present in healthy controls, and all seven meningiomas analyzed displayed loss of the wild-type allele according to the classic two-hit model for tumor-suppressor genes. In silico modeling predicted the variant to affect the tertiary structure of the protein, and functional analyses showed that the activity of the altered SUFU was significantly reduced and therefore led to dysregulated hedgehog (Hh) signaling. SUFU is a known tumor-suppressor gene previously associated with childhood medulloblastoma predisposition. Our genetic and functional analyses indicate that germline mutations in SUFU also predispose to meningiomas, particularly to multiple meningiomas. It is possible that other genic mutations resulting in aberrant activation of the Hh pathway might underlie meningioma predisposition in families with an unknown etiology.
Kijima C, Miyashita T, Suzuki M, et al.Two cases of nevoid basal cell carcinoma syndrome associated with meningioma caused by a PTCH1 or SUFU germline mutation.
Fam Cancer. 2012; 11(4):565-70 [PubMed
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Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by developmental defects and tumorigenesis. The gene responsible for NBCCS is PTCH1. The development of meningioma in NBCCS patients is a rare event. Here, we report two cases of NBCCS in which meningiomas did develop. The first patient carried a germline mutation in one allele of PTCH1, c.290dupA (p.N97KfsX43). In addition, the meningioma sample carried a somatic mutation, c.307delG (p.Val103LeufsX15), in the other allele of the same gene, suggesting a second hit. This is the first case of NBCCS-associated meningioma explained by the standard two-hit hypothesis. The second patient had a germline nonsense mutation in the SUFU gene, c.550C>T (p.Q184X). SUFU is located downstream of PTCH1 in the sonic hedgehog signaling pathway. This is the second time a germline mutation in SUFU has been found to cause NBCCS. Together with the previous report describing three cases of non-NBCCS medulloblastoma carrying a germline mutation in this gene, individuals with a SUFU germline mutation are expected to have a markedly high risk of developing medulloblastoma and probably meningioma.
Jorgensen TJ, Ruczinski I, Yao Shugart Y, et al.A population-based study of hedgehog pathway gene variants in relation to the dual risk of basal cell carcinoma plus another cancer.
Cancer Epidemiol. 2012; 36(5):e288-93 [PubMed
] Free Access to Full Article Related Publications
INTRODUCTION: A personal history of basal cell carcinoma (BCC) is associated with increased risk of other malignancies, but the reason is unknown. The hedgehog pathway is critical to the etiology of BCC, and is also believed to contribute to susceptibility to other cancers. This study tested the hypothesis that hedgehog pathway and pathway-related gene variants contribute to the increased risk of subsequent cancers among those with a history of BCC.
METHODS: The study was nested within the ongoing CLUE II cohort study, established in 1989 in Washington County, Maryland, USA. The study consisted of a cancer-free control group (n=2296) compared to three different groups of cancer cases ascertained through 2007, those diagnosed with: (1) Other (non-BCC) cancer only (n=2349); (2) BCC only (n=534); and (3) BCC plus other cancer (n=446). The frequencies of variant alleles were compared among these four groups for 20 single nucleotide polymorphisms (SNPs) in 6 hedgehog pathway genes (SHH, IHH, PTCH2, SMO, GLI1, SUFU), and also 22 SNPs in VDR and 8 SNPs in FAS, which have cross-talk with the hedgehog pathway.
RESULTS: Comparing those with both BCC and other cancer versus those with no cancer, no significant associations were observed for any of the hedgehog pathway SNPs, or for the FAS SNPs. One VDR SNP was nominally significantly associated with the BCC cancer-prone phenotype, rs11574085 [per minor allele odds ratio (OR) 1.38, 95% confidence interval (CI) 1.05-1.82; p-value=0.02].
CONCLUSION: The hedgehog pathway gene SNPs studied, along with the VDR and FAS SNPs studied, are not strongly associated with the BCC cancer-prone phenotype.
Brugières L, Remenieras A, Pierron G, et al.High frequency of germline SUFU mutations in children with desmoplastic/nodular medulloblastoma younger than 3 years of age.
J Clin Oncol. 2012; 30(17):2087-93 [PubMed
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PURPOSE: Germline mutations of the SUFU gene have been shown to be associated with genetic predisposition to medulloblastoma, mainly in families with multiple cases of medulloblastoma and/or in patients with symptoms similar to those of Gorlin syndrome. To evaluate the contribution of these mutations to the genesis of sporadic medulloblastomas, we screened a series of unselected patients with medulloblastoma for germline SUFU mutations.
PATIENTS AND METHODS: A complete mutational analysis of the SUFU gene was performed on genomic DNA in all 131 consecutive patients treated for medulloblastoma in the pediatrics department of the Institut Gustave Roussy between 1972 and 2009 and for whom a blood sample was available.
RESULTS: We identified eight germline mutations of the SUFU gene: one large genomic duplication and seven point mutations. Mutations were identified in three of three individuals with medulloblastoma with extensive nodularity, four of 20 with desmoplastic/nodular medulloblastomas, and one of 108 with other subtypes. All eight patients were younger than 3 years of age at diagnosis. The mutations were inherited from the healthy father in four of six patient cases in which the parents accepted genetic testing; de novo mutations accounted for the other two patient cases. Associated events were macrocrania in six patients, hypertelorism in three patients, and multiple basal cell carcinomas in the radiation field after age 18 years in one patient.
CONCLUSION: These data indicate that germline SUFU mutations were responsible for a high proportion of desmoplastic medulloblastoma in children younger than 3 years of age. Genetic testing should be offered to all children diagnosed with sonic hedgehog-driven medulloblastoma at a young age.
Esophageal adenocarcinoma (EAC) is the most prevalent esophageal cancer type in the United States. The TNF-α/mTOR pathway is known to mediate the development of EAC. Additionally, aberrant activation of Gli1, downstream effector of the Hedgehog (HH) pathway, has been observed in EAC. In this study, we found that an activated mTOR/S6K1 pathway promotes Gli1 transcriptional activity and oncogenic function through S6K1-mediated Gli1 phosphorylation at Ser84, which releases Gli1 from its endogenous inhibitor, SuFu. Moreover, elimination of S6K1 activation by an mTOR pathway inhibitor enhances the killing effects of the HH pathway inhibitor. Together, our results established a crosstalk between the mTOR/S6K1 and HH pathways, which provides a mechanism for SMO-independent Gli1 activation and also a rationale for combination therapy for EAC.
Fellay CN, Frappaz D, Sunyach MP, et al.Medulloblastomas in adults: prognostic factors and lessons from paediatrics.
Curr Opin Neurol. 2011; 24(6):626-32 [PubMed
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PURPOSE OF REVIEW: Medulloblastomas are very rare in adults. Usual treatment consists of craniospinal radiation with or without chemotherapy. Current efforts focus on a better understanding of tumour biology, stratifying patients into risk groups and adapting treatment accordingly. This review discusses clinical and new molecular risk factors that will help to optimize treatment in adult medulloblastoma patients.
RECENT FINDINGS: The clinical risk stratification should be complemented with new molecular prognostic markers. Gene-expression profiling has permitted identification of four to six molecular medulloblastoma subgroups. The WNT subgroup shows overexpression of genes of the WNT/wingless signalling pathway with frequent mutations of the CNNTB1 gene, loss of chromosome 6 and accumulation of nuclear β-catenin, and is most often seen in children with medulloblastomas of classical histology. This variant has a good prognosis. Activation of the sonic hedgehog pathway with frequent mutations of the PTCH and SUFU genes, loss of 9q, and positivity for GLI1 and SFRP1 is more frequent in children less than 3 years old and in adults, commonly associated with desmoplastic histology. Other subgroups are not so well defined and have overlapping characteristics, but MYC/MYCN amplification, 17q gain and, large cell/anaplastic histology are factors of poor prognosis.
SUMMARY: New molecular subgroups will help tailor treatment and further develop new targeted therapies. Prospective and ideally randomized trials should be performed in adults, including risk stratification by molecular markers, to identify optimal treatment for each risk group.
Basal cell carcinoma of the skin typically carries genetic alterations in components of the hedgehog (HH) signaling pathway. Previously, we generated a knockout mouse with a loss-of-function mutation in suppressor of fused (Sufu), an essential repressor of the pathway downstream of Hh ligand cell surface reception. Mice heterozygous for the mutated Sufu allele develop a skin phenotype that includes lesions similar to basaloid follicular hamartomas. The purpose of the current study was to test the possibility that the simultaneous loss of the tumor suppressor gene, transformation related protein 53 (Trp53), would aggravate the Sufu skin phenotype since Trp53 loss is known to enhance the growth of other Hh-driven tumors. Consistent with previous reports, medulloblastomas and rhabdomyosarcomas developed in Sufu(+/-) ;Trp53(-/-) mice. However, the characteristic Sufu(+/-) skin phenotype was not altered in the absence of Trp53, and showed no changes in latency, multiplicity, cellular phenotype, or proliferative capacity of the basaloid lesions. This finding was both novel and intriguing and demonstrated a differential, tissue-specific sensitivity to Sufu and Trp53 tumor suppressor gene loss, which may be linked to developmental stage and the degree of proliferative activity in specific cell types.
Gli zinc-finger proteins are transcription factors involved in the intracellular signal transduction controlled by the Hedgehog family of secreted molecules. They are frequently mutated in human congenital malformations, and their abnormal regulation leads to tumorigenesis. Genetic studies in several model systems indicate that their activity is tightly regulated by Hedgehog signaling through various posttranslational modifications, including phosphorylation, ubiquitin-mediated degradation, and proteolytic processing, as well as through nucleocytoplasmic shuttling. In vertebrate cells, primary cilia are required for the sensing of Hedgehog pathway activity and involved in the processing and activation of Gli proteins. Two evolutionarily conserved Hedgehog pathway components, Suppressor of fused and Kif7, are core intracellular regulators of mammalian Gli proteins. Recent studies revealed that Gli proteins are also regulated transcriptionally and posttranslationally through noncanonical mechanisms independent of Hedgehog signaling. In this review, we describe the regulation of Gli proteins during development and discuss possible mechanisms for their abnormal activation during tumorigenesis.
BACKGROUND: Hedgehog (Hh) signaling is over-activated in several solid tumors where it plays a central role in cell growth, stroma recruitment and tumor progression. In the Hh signaling pathway, the Smoothened (SMO) receptor comprises a primary drug target with experimental small molecule SMO antagonists currently being evaluated in clinical trials.
PRINCIPAL FINDINGS: Using Shh-Light II (Shh-L2) and alkaline phosphatase (AP) based screening formats on a "focused diversity" library we identified a novel small molecule inhibitor of the Hh pathway, MS-0022 (2-bromo-N-(4-(8-methylimidazo[1,2-a]pyridin-2-yl)phenyl)benzamide). MS-0022 showed effective Hh signaling pathway inhibition at the level of SMO in the low nM range, and Hh pathway inhibition downstream of Suppressor of fused (SUFU) in the low µM range. MS-0022 reduced growth in the tumor cell lines PANC-1, SUIT-2, PC-3 and FEMX in vitro. MS-0022 treatment led to a transient delay of tumor growth that correlated with a reduction of stromal Gli1 levels in SUIT-2 xenografts in vivo.
SIGNIFICANCE: We document the in vitro and in vivo efficacy and bioavailability of a novel small molecule SMO antagonist, MS-0022. Although MS-0022 primarily interferes with Hh signaling at the level of SMO, it also has a downstream inhibitory effect and leads to a stronger reduction of growth in several tumor cell lines when compared to related SMO antagonists.
Kim TJ, Lee JY, Hwang TK, et al.Hedgehog signaling protein expression and its association with prognostic parameters in prostate cancer: a retrospective study from the view point of new 2010 anatomic stage/prognostic groups.
J Surg Oncol. 2011; 104(5):472-9 [PubMed
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BACKGROUND: The expression of Hedgehog (Hh) signaling pathway in prostate cancer is well-known but its clinicopathologic role has not been elucidated well.
METHODS: Prostatectomy cases of prostate cancer (n=155) were prepared and assessed by clinicopathologic parameters including new 2010 anatomic stage/prognostic groups (ASPG) of prostate cancer. The expression of five Hh signaling proteins including Sonic hedgehog (Shh), Patched, Smoothened, and GLIoma-associated oncogene, in addition with Suppressor of fused (Su(fu)) were analyzed immunohistochemically. Real-time polymerase chain reaction was performed to assess the mRNA expression status.
RESULTS: The expression of each Hh signaling protein was significantly correlated with poor prognostic parameters such as larger tumor size, high pretreatment prostate-specific antigen (PSA), high Gleason score, perineural invasion and new ASPG. Among Hh signaling proteins, Sonic hedgehog and Smoothened expressions tend to have a significantly higher risk of PSA recurrence (P<0.001 and P=0.011, respectively). Multivariate analysis proved Shh expression as independent prognostic factors of PSA recurrence along with Gleason score, ASPG, tumor volume, and pretreatment PSA.
CONCLUSIONS: Hh signaling activity is significantly associated with worse prognostic parameters. Shh can be regarded as a poor prognostic factor for PSA recurrence.