SMO

Gene Summary

Gene:SMO; smoothened, frizzled class receptor
Aliases: Gx, CRJS, SMOH, FZD11
Location:7q32.1
Summary:The protein encoded by this gene is a G protein-coupled receptor that interacts with the patched protein, a receptor for hedgehog proteins. The encoded protein tranduces signals to other proteins after activation by a hedgehog protein/patched protein complex. [provided by RefSeq, Jul 2010]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:smoothened homolog
Source:NCBIAccessed: 15 March, 2017

Ontology:

What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 15 March 2017 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 15 March, 2017 using data from PubMed, MeSH and CancerIndex

Latest Publications: SMO (cancer-related)

Baker E, Jacobs C, Martinie J, et al.
Mixed Hepatocellular Carcinoma, Neuroendocrine Carcinoma of the Liver.
Am Surg. 2016; 82(11):1121-1125 [PubMed] Related Publications
We present the case of a 76-year-old male found to have a large tumor involving the left lateral lobe of the liver, presumed to be hepatocellular carcinoma (HCC). After resection, pathologic features demonstrated both high-grade HCC and high-grade neuroendocrine carcinoma (NEC). Areas of NEC stained strongly for synaptophysin, which was not present in HCC component. The HCC component stained strongly for Hep-Par 1, which was not present in the NEC component. The patient underwent genetic analysis for biomarkers common to both tumor cell types. Both tumor components contained gene mutations in CTNNB1 gene (S33F located in exon 3). They also shared mutations in PD-1, PGP, and SMO. Mixed HCC/NEC tumors have been rarely reported in the literature with generally poor outcomes. This patient has been referred for adjuvant platinum-based chemotherapy; genetic biomarker analysis may provide some insight to guide targeted chemotherapy.

Wu X, Xia M, Chen D, et al.
Profiling of downregulated blood-circulating miR-150-5p as a novel tumor marker for cholangiocarcinoma.
Tumour Biol. 2016; 37(11):15019-15029 [PubMed] Related Publications
Altered microRNA (miRNA) expression plays a role in cholangiocarcinoma (CCA) development; thus, detection of blood-circulating miRNAs could be useful as CCA markers. This study profiled serum miRNA levels in patients with primary sclerosing cholangitis (PSC) and CCA and then assessed the role of miR-150-5p in CCA progression in vitro. Three samples were randomly selected from each of 50 sera of healthy controls, 30 PSC sera, and 28 CCA sera with matched bile samples for miRNA microarray profiling. The dysregulated miRNAs were confirmed using qRT-PCR, and miR-150-5p was selected for further in vitro and ex vivo studies. The miRNA microarray identified three dysregulated miRNAs in both CCA and PSC samples, while miR-150-5p level was consistently lower in CCA sera, bile, and tissues than in normal control and PSC sera (P < 0.05). Furthermore, levels of miR-150-5p were associated with serum carbohydrate antigen 19-9 (CA19-9) levels and CCA pathological grade. Bioinformatic Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses showed that miR-150-5p could regulate hand-full gene pathways, including cancer pathway (P < 0.01). However, overexpression of miR-150-5p inhibited proliferation, migration, and invasion capability of CCA cells (P < 0.05). Luciferase reporter assay showed that miR-150-5p bound to an oncogene Ets including gene-1 (ELK1), and Western blot data confirmed that miR-150-5p suppressed ELK1 expression in CCA cell lines. These results suggest that reduced miR-150-5p expression could contribute to CCA development and progression due to uncontrolled ELK1 expression. Thus, further study could evaluate miR-150-5p as a novel target and predictor for CCA prevention and treatment.

Yuzawa S, Nishihara H, Tanaka S
Genetic landscape of meningioma.
Brain Tumor Pathol. 2016; 33(4):237-247 [PubMed] Related Publications
Meningioma is the most common intracranial tumor, arising from arachnoid cells of the meninges. Monosomy 22 and inactivating mutations of NF2 are well-known genetic alterations of meningiomas. More recently, mutations in TRAF7, AKT1, KLF4, SMO, and PIK3CA were identified by next-generation sequencing. We here reviewed 553 meningiomas for the mutational patterns of the six genes. NF2 aberration was observed in 55 % of meningiomas. Mutations of TRAF7, AKT1, KLF4, PIK3CA, and SMO were identified in 20, 9, 9, 4.5, and 3 % of cases, respectively. Altogether, 80 % of cases harbored at least one of the genetic alterations in these genes. NF2 alterations and mutations of the other genes were mutually exclusive with a few exceptions. Clinicopathologically, tumors with mutations in TRAF7/AKT1 and SMO shared specific features: they were located in the anterior fossa, median middle fossa, or anterior calvarium, and most of them were meningothelial or transitional meningiomas. TRAF7/KLF4 type meningiomas showed different characteristics in that they occurred in the lateral middle fossa and median posterior fossa as well as anterior fossa and median middle fossa, and contained a secretory meningioma component. We also discuss the mutational hotspots of these genes and other genetic/cytogenetic alterations contributing to tumorigenesis or progression of meningiomas.

Yamasaki A, Onishi H, Imaizumi A, et al.
Protein-bound Polysaccharide-K Inhibits Hedgehog Signaling Through Down-regulation of MAML3 and RBPJ Transcription Under Hypoxia, Suppressing the Malignant Phenotype in Pancreatic Cancer.
Anticancer Res. 2016; 36(8):3945-52 [PubMed] Related Publications
Hedgehog signaling is activated in pancreatic cancer and could be a therapeutic target. We previously demonstrated that recombination signal binding protein for immunoglobulin-kappa-J region (RBPJ) and mastermind-like 3 (MAML3) contribute to the hypoxia-induced up-regulation of Smoothened (SMO) transcription. We have also shown that protein-bound polysaccharide-K (PSK) could be effective for refractory pancreatic cancer that down-regulates SMO transcription under hypoxia. In this study, we evaluated whether the anticancer mechanism of PSK involves inhibiting RBPJ and MAML3 expression under hypoxia. PSK reduced SMO, MAML3 and RBPJ expression in pancreatic cancer cells under hypoxia. PSK also blocked RBPJ-induced invasiveness under hypoxia by inhibiting matrix metalloproteinase expression. Lastly, we showed that PSK attenuated RBPJ-induced proliferation both in vitro and in vivo. These results suggest that PSK suppresses Hedgehog signaling through down-regulation of MAML3 and RBPJ transcription under hypoxia, inhibiting the induction of a malignant phenotype in pancreatic cancer. Our results may lead to development of new treatments for refractory pancreatic cancer using PSK as a Hedgehog inhibitor.

Tibes R
Sonidegib phosphate: new approval for basal cell carcinoma.
Drugs Today (Barc). 2016; 52(5):295-303 [PubMed] Related Publications
Basal cell carcinoma (BCC), although mostly locally confined, is the most common cancer. Most BCCs harbor inactivating mutations in the membrane receptor/gene Ptch, thereby activating the Hedgehog signaling pathway (Hh) via the essential signaling molecule Smoothened (SMO). Novel small-molecule inhibitors or antagonists of SMO have shown excellent response rates in patients with locally advanced, unresectable and metastatic BCC in roughly 35-60% of patients, with disease control rates and clinical benefit being even higher. Sonidegib is the second-in-class SMO inhibitor approved for locally advanced, unresectable and metastatic BCC. Sonidegib is given once daily continuously, with specific side effects as listed in the label indication. Resistance develops over time and knowledge gleaned from other SMO inhibitors indicates that SMO mutations preventing drug binding as well as mechanisms activating the Hh pathway downstream of SMO are responsible, ultimately reactivating Hh pathway signaling. The next challenge will be to define novel salvage and SMO combination strategies for BCC and other tumors.

Lai J, Zhou Z, Tang XJ, et al.
A Tumor-Specific Neo-Antigen Caused by a Frameshift Mutation in BAP1 Is a Potential Personalized Biomarker in Malignant Peritoneal Mesothelioma.
Int J Mol Sci. 2016; 17(5) [PubMed] Free Access to Full Article Related Publications
Malignant peritoneal mesothelioma (MPM) is an aggressive rare malignancy associated with asbestos exposure. A better understanding of the molecular pathogenesis of MPM will help develop a targeted therapy strategy. Oncogene targeted depth sequencing was performed on a tumor sample and paired peripheral blood DNA from a patient with malignant mesothelioma of the peritoneum. Four somatic base-substitutions in NOTCH2, NSD1, PDE4DIP, and ATP10B and 1 insert frameshift mutation in BAP1 were validated by the Sanger method at the transcriptional level. A 13-amino acids neo-peptide of the truncated Bap1 protein, which was produced as a result of this novel frameshift mutation, was predicted to be presented by this patient's HLA-B protein. The polyclonal antibody of the synthesized 13-mer neo-peptide was produced in rabbits. Western blotting results showed a good antibody-neoantigen specificity, and Immunohistochemistry (IHC) staining with the antibody of the neo-peptide clearly differentiated neoplastic cells from normal cells. A search of the Catalogue of Somatic Mutations in Cancer (COSMIC) database also revealed that 53.2% of mutations in BAP1 were frameshift indels with neo-peptide formation. An identified tumor-specific neo-antigen could be the potential molecular biomarker for personalized diagnosis to precisely subtype rare malignancies such as MPM.

He P, Zhang HX, Sun CY, et al.
Overexpression of SASH1 Inhibits the Proliferation, Invasion, and EMT in Hepatocarcinoma Cells.
Oncol Res. 2016; 24(1):25-32 [PubMed] Related Publications
The SASH1 (SAM- and SH3-domain containing 1) gene, a member of the SLY (SH3 domain containing expressed in lymphocytes) family of signal adapter proteins, has been implicated in tumorigenesis of many types of cancers. However, the role and mechanism of SASH1 in the invasion and metastasis of hepatocarcinoma are largely unknown. In this study, we investigated the role and mechanism of SASH1 in the invasion and metastasis of hepatocarcinoma. Our results showed that SASH1 was lowly expressed in hepatocarcinoma cell lines. The in vitro experiments showed that overexpression of SASH1 inhibited the proliferation and migration/invasion of hepatocarcinoma cells, as well as the epithelial-mesenchymal transition (EMT) progress. Furthermore, overexpression of SASH1 suppressed the expression of Shh as well as Smo, Ptc, and Gli-1 in hepatocarcinoma cells. Taken together, these results suggest that overexpression of SASH1 inhibited the proliferation and invasion of hepatocarcinoma cells through the inactivation of Shh signaling pathway. Therefore, these findings reveal that SASH1 may be a potential therapeutic target for the treatment of hepatocarcinoma.

Todorovic Balint M, Jelicic J, Mihaljevic B, et al.
Gene Mutation Profiles in Primary Diffuse Large B Cell Lymphoma of Central Nervous System: Next Generation Sequencing Analyses.
Int J Mol Sci. 2016; 17(5) [PubMed] Free Access to Full Article Related Publications
The existence of a potential primary central nervous system lymphoma-specific genomic signature that differs from the systemic form of diffuse large B cell lymphoma (DLBCL) has been suggested, but is still controversial. We investigated 19 patients with primary DLBCL of central nervous system (DLBCL CNS) using the TruSeq Amplicon Cancer Panel (TSACP) for 48 cancer-related genes. Next generation sequencing (NGS) analyses have revealed that over 80% of potentially protein-changing mutations were located in eight genes (CTNNB1, PIK3CA, PTEN, ATM, KRAS, PTPN11, TP53 and JAK3), pointing to the potential role of these genes in lymphomagenesis. TP53 was the only gene harboring mutations in all 19 patients. In addition, the presence of mutated TP53 and ATM genes correlated with a higher total number of mutations in other analyzed genes. Furthermore, the presence of mutated ATM correlated with poorer event-free survival (EFS) (p = 0.036). The presence of the mutated SMO gene correlated with earlier disease relapse (p = 0.023), inferior event-free survival (p = 0.011) and overall survival (OS) (p = 0.017), while mutations in the PTEN gene were associated with inferior OS (p = 0.048). Our findings suggest that the TP53 and ATM genes could be involved in the molecular pathophysiology of primary DLBCL CNS, whereas mutations in the PTEN and SMO genes could affect survival regardless of the initial treatment approach.

Hyun J, Wang S, Kim J, et al.
MicroRNA-378 limits activation of hepatic stellate cells and liver fibrosis by suppressing Gli3 expression.
Nat Commun. 2016; 7:10993 [PubMed] Free Access to Full Article Related Publications
Hedgehog (Hh) signalling regulates hepatic fibrogenesis. MicroRNAs (miRNAs) mediate various cellular processes; however, their role in liver fibrosis is unclear. Here we investigate regulation of miRNAs in chronically damaged fibrotic liver. MiRNA profiling shows that expression of miR-378 family members (miR-378a-3p, miR-378b and miR-378d) declines in carbon tetrachloride (CCl4)-treated compared with corn-oil-treated mice. Overexpression of miR-378a-3p, directly targeting Gli3 in activated hepatic stellate cells (HSCs), reduces expression of Gli3 and profibrotic genes but induces gfap, the inactivation marker of HSCs, in CCl4-treated liver. Smo blocks transcriptional expression of miR-378a-3p by activating the p65 subunit of nuclear factor-κB (NF-κB). The hepatic level of miR-378a-3p is inversely correlated with the expression of Gli3 in tumour and non-tumour tissues in human hepatocellular carcinoma. Our results demonstrate that miR-378a-3p suppresses activation of HSCs by targeting Gli3 and its expression is regulated by Smo-dependent NF-κB signalling, suggesting miR-378a-3p has therapeutic potential for liver fibrosis.

Li R, Pu X, Chang JY, et al.
MiRNA-Related Genetic Variations Associated with Radiotherapy-Induced Toxicities in Patients with Locally Advanced Non-Small Cell Lung Cancer.
PLoS One. 2016; 11(3):e0150467 [PubMed] Free Access to Full Article Related Publications
Severe radiation-induced toxicities limit treatment efficacy and compromise outcomes of lung cancer. We aimed to identify microRNA-related genetic variations as biomarkers for the prediction of radiotherapy-induced acute toxicities. We genotyped 233 SNPs (161 in microRNA binding site and 72 in processing gene) and analyzed their associations with pneumonitis and esophagitis in 167 stage III NSCLC patients received definitive radiation therapy. Sixteen and 11 SNPs were associated with esophagitis and pneumonitis, respectively. After multiple comparison correction, RPS6KB2:rs10274, SMO:rs1061280, SMO:rs1061285 remained significantly associated with esophagitis, while processing gene DGCR8:rs720014, DGCR8:rs3757, DGCR8:rs1633445 remained significantly associated with pneumonitis. Patients with the AA genotype of RPS6KB2:rs10274 had an 81% reduced risk of developing esophagitis (OR: 0.19, 95% CI: 0.07-0.51, p = 0.001, q = 0.06). Patients with the AG+GG genotype of SMO:rs1061280 had an 81% reduced risk of developing esophagitis (OR: 0.19, 95% CI: 0.07-0.53, p = 0.001, q = 0.06). Patients with the GG+GA genotype of DGCR8:rs720014 had a 3.54-fold increased risk of pneumonitis (OR: 3.54, 95% CI: 1.65-7.61, p <0.05, q <0.1). Significantly cumulative effects of the top SNPs were observed for both toxicities (P-trend <0.001). Using bioinformatics tools, we found that the genotype of rs10274 was associated with altered expression of the RPS6KB2 gene. Gene-based analysis showed DGCR8 (p = 0.010) and GEMIN4 (p = 0.039) were the top genes associated with the risk of developing pneumonitis. Our results provide strong evidence that microRNA-related genetic variations contribute to the development of radiotherapy-induced acute esophagitis and pneumonitis and could thus serve as biomarkers to help accurately predict radiotherapy-induced toxicity in NSCLC patients.

Bonilla X, Parmentier L, King B, et al.
Genomic analysis identifies new drivers and progression pathways in skin basal cell carcinoma.
Nat Genet. 2016; 48(4):398-406 [PubMed] Related Publications
Basal cell carcinoma (BCC) of the skin is the most common malignant neoplasm in humans. BCC is primarily driven by the Sonic Hedgehog (Hh) pathway. However, its phenotypic variation remains unexplained. Our genetic profiling of 293 BCCs found the highest mutation rate in cancer (65 mutations/Mb). Eighty-five percent of the BCCs harbored mutations in Hh pathway genes (PTCH1, 73% or SMO, 20% (P = 6.6 × 10(-8)) and SUFU, 8%) and in TP53 (61%). However, 85% of the BCCs also harbored additional driver mutations in other cancer-related genes. We observed recurrent mutations in MYCN (30%), PPP6C (15%), STK19 (10%), LATS1 (8%), ERBB2 (4%), PIK3CA (2%), and NRAS, KRAS or HRAS (2%), and loss-of-function and deleterious missense mutations were present in PTPN14 (23%), RB1 (8%) and FBXW7 (5%). Consistent with the mutational profiles, N-Myc and Hippo-YAP pathway target genes were upregulated. Functional analysis of the mutations in MYCN, PTPN14 and LATS1 suggested their potential relevance in BCC tumorigenesis.

Bai XY, Zhang XC, Yang SQ, et al.
Blockade of Hedgehog Signaling Synergistically Increases Sensitivity to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Non-Small-Cell Lung Cancer Cell Lines.
PLoS One. 2016; 11(3):e0149370 [PubMed] Free Access to Full Article Related Publications
Aberrant activation of the hedgehog (Hh) signaling pathway has been implicated in the epithelial-to-mesenchymal transition (EMT) and cancer stem-like cell (CSC) maintenance; both processes can result in tumor progression and treatment resistance in several types of human cancer. Hh cooperates with the epidermal growth factor receptor (EGFR) signaling pathway in embryogenesis. We found that the Hh signaling pathway was silenced in EGFR-TKI-sensitive non-small-cell lung cancer (NSCLC) cells, while it was inappropriately activated in EGFR-TKI-resistant NSCLC cells, accompanied by EMT induction and ABCG2 overexpression. Upregulation of Hh signaling through extrinsic SHH exposure downregulated E-cadherin expression and elevated Snail and ABCG2 expression, resulting in gefitinib tolerance (P < 0.001) in EGFR-TKI-sensitive cells. Blockade of the Hh signaling pathway using the SMO antagonist SANT-1 restored E-cadherin expression and downregulate Snail and ABCG2 in EGFR-TKI-resistant cells. A combination of SANT-1 and gefitinib markedly inhibited tumorigenesis and proliferation in EGFR-TKI-resistant cells (P < 0.001). These findings indicate that hyperactivity of Hh signaling resulted in EGFR-TKI resistance, by EMT introduction and ABCG2 upregulation, and blockade of Hh signaling synergistically increased sensitivity to EGFR-TKIs in primary and secondary resistant NSCLC cells. E-cadherin expression may be a potential biomarker of the suitability of the combined application of an Hh inhibitor and EGFR-TKIs in EGFR-TKI-resistant NSCLCs.

Mastrantonio R, Cervelli M, Pietropaoli S, et al.
HIV-Tat Induces the Nrf2/ARE Pathway through NMDA Receptor-Elicited Spermine Oxidase Activation in Human Neuroblastoma Cells.
PLoS One. 2016; 11(2):e0149802 [PubMed] Free Access to Full Article Related Publications
Previously, we reported that HIV-Tat elicits spermine oxidase (SMO) activity upregulation through NMDA receptor (NMDAR) stimulation in human SH-SY5Y neuroblastoma cells, thus increasing ROS generation, which in turn leads to GSH depletion, oxidative stress, and reduced cell viability. In several cell types, ROS can trigger an antioxidant cell response through the transcriptional induction of oxidative stress-responsive genes regulated by the nuclear factor erythroid 2-related factor 2 (Nrf2). Here, we demonstrate that Tat induces both antioxidant gene expression and Nrf2 activation in SH-SY5Y cells, mediated by SMO activity. Furthermore, NMDAR is involved in Tat-induced Nrf2 activation. These findings suggest that the NMDAR/SMO/Nrf2 pathway is an important target for protection against HIV-associated neurocognitive disorders.

Benvenuto M, Masuelli L, De Smaele E, et al.
In vitro and in vivo inhibition of breast cancer cell growth by targeting the Hedgehog/GLI pathway with SMO (GDC-0449) or GLI (GANT-61) inhibitors.
Oncotarget. 2016; 7(8):9250-70 [PubMed] Free Access to Full Article Related Publications
Aberrant Hedgehog (Hh)/glioma-associated oncogene (GLI) signaling has been implicated in cancer progression. Here, we analyzed GLI1, Sonic Hedgehog (Shh) and NF-κB expression in 51 breast cancer (ductal carcinoma) tissues using immunohistochemistry. We found a positive correlation between nuclear GLI1 expression and tumor grade in ductal carcinoma cases. Cytoplasmic Shh staining significantly correlated with a lower tumor grade. Next, the in vitro effects of two Hh signaling pathway inhibitors on breast cancer cell lines were evaluated using the Smoothened (SMO) antagonist GDC-0449 and the direct GLI1 inhibitor GANT-61. GDC-0449 and GANT-61 exhibited the following effects: a) inhibited breast cancer cell survival; b) induced apoptosis; c) inhibited Hh pathway activity by decreasing the mRNA expression levels of GLI1 and Ptch and inhibiting the nuclear translocation of GLI1; d) increased/decreased EGFR and ErbB2 protein expression, reduced p21-Ras and ERK1/ERK2 MAPK activities and inhibited AKT activation; and e) decreased the nuclear translocation of NF-κB. However, GANT-61 exerted these effects more effectively than GDC-0449. The in vivo antitumor activities of GDC-0449 and GANT-61 were analyzed in BALB/c mice that were subcutaneously inoculated with mouse breast cancer (TUBO) cells. GDC-0449 and GANT-61 suppressed tumor growth of TUBO cells in BALB/c mice to different extents. These findings suggest that targeting the Hh pathway using antagonists that act downstream of SMO is a more efficient strategy than using antagonists that act upstream of SMO for interrupting Hh signaling in breast cancer.

Wang Y, Peng Q, Jia H, Du X
Prognostic value of hedgehog signaling pathway in digestive system cancers: A systematic review and meta-analysis.
Cancer Biomark. 2016; 16(1):71-9 [PubMed] Related Publications
BACKGROUND: The Hedgehog (Hh) signaling pathway has recently been reported to be associated with the prognosis of digestive system cancers. However, the results are inconsistent.
OBJECTIVE: This study aimed to investigate the association between Hh pathway components and survival outcomes in patients with digestive system cancers.
METHODS: We conducted a comprehensive retrieval in PubMed, EMBASE and Cochrane library for relevant literatures until May 1st, 2015. The pooled hazard ratios (HRs) for overall survival (OS) and disease-free survival (DFS) with 95% confidence intervals (CIs) were calculated to clarify the prognostic value of Hh pathway components, including Shh, Gli1, Gli2, Smo and Ptch1.
RESULTS: A total of 16 eligible articles with 3222 patients were included in the meta-analysis. Pooled HR suggested that over-expression of Shh and Gli1 were both associated with poor OS (HR = 1.87, 95% CI: 1.14-3.07 and HR = 1.96, 95% CI: 1.66-2.32, respectively) and DFS (HR = 2.37, 95% CI: 1.19-4.72 and HR = 2.18, 95% CI: 1.61-2.96, respectively). In addition, over-expression of Smo was associated with poor DFS (HR = 1.38, 95% CI: 1.08-1.75).
CONCLUSIONS: This study reveals that over-expressed Hh pathway components, including Shh, Gli1 and Smo, are associated with poor prognosis in digestive system cancer patients. Hh signaling pathway may become a potential therapeutic target in digestive system cancers.

Ally MS, Ransohoff K, Sarin K, et al.
Effects of Combined Treatment With Arsenic Trioxide and Itraconazole in Patients With Refractory Metastatic Basal Cell Carcinoma.
JAMA Dermatol. 2016; 152(4):452-6 [PubMed] Free Access to Full Article Related Publications
IMPORTANCE: Tumor resistance is an emerging problem for Smoothened (SMO) inhibitor-treated metastatic basal cell carcinoma (BCC). Arsenic trioxide and itraconazole antagonize the hedgehog (HH) pathway at sites distinct from those treated by SMO inhibitors.
OBJECTIVE: To determine whether administration of intravenous arsenic trioxide and oral itraconazole in patients with metastatic BCC is associated with a reduction in GLI1 messenger RNA expression in tumor and/or normal skin biopsy samples.
DESIGN, SETTING, AND PARTICIPANTS: Five men with metastatic BCC who experienced relapse after SMO inhibitor treatment underwent intravenous arsenic trioxide treatment for 5 days, every 28 days, and oral itraconazole treatment on days 6 to 28. Data were collected from April 10 to November 14, 2013. Follow-up was completed on October 3, 2015, and data were analyzed from June 5 to October 6, 2015.
MAIN OUTCOMES AND MEASURES: The primary outcome was the change in messenger RNA levels of the GLI family zinc finger 1 (GLI1) gene (HH-pathway target gene) in biopsy specimens of normal skin or BCC before and after treatment. Secondary objectives were evaluation of tumor response and tolerability.
RESULTS: Of the 5 patients (mean [SD] age, 52 [9] years; age range, 43-62 years), 3 completed 3 cycles of treatment and 2 discontinued treatment early owing to disease progression or adverse events. Adverse effects included grade 2 transaminitis and grade 4 leukopenia with a grade 3 infection. Overall, arsenic trioxide and itraconazole reduced GLI1 messenger RNA levels by 75% from baseline (P < .001). The best overall response after 3 treatment cycles was stable disease in 3 patients.
CONCLUSIONS AND RELEVANCE: Targeting the HH pathway with sequential arsenic trioxide and itraconazole treatment is a feasible treatment for metastatic BCC. Although some patients experienced stable disease for 3 months, none had tumor shrinkage, which may be owing to transient GLI1 suppression with sequential dosing. Continuous dosing may be required to fully inhibit the HH pathway and achieve clinical response.

Hoang-Minh LB, Deleyrolle LP, Siebzehnrubl D, et al.
Disruption of KIF3A in patient-derived glioblastoma cells: effects on ciliogenesis, hedgehog sensitivity, and tumorigenesis.
Oncotarget. 2016; 7(6):7029-43 [PubMed] Free Access to Full Article Related Publications
KIF3A, a component of the kinesin-2 motor, is necessary for the progression of diverse tumor types. This is partly due to its role in regulating ciliogenesis and cell responsiveness to sonic hedgehog (SHH). Notably, primary cilia have been detected in human glioblastoma multiforme (GBM) tumor biopsies and derived cell lines. Here, we asked whether disrupting KIF3A in GBM cells affected ciliogenesis, in vitro growth and responsiveness to SHH, or tumorigenic behavior in vivo. We used a lentiviral vector to create three patient-derived GBM cell lines expressing a dominant negative, motorless form of Kif3a (dnKif3a). In all unmodified lines, we found that most GBM cells were capable of producing ciliated progeny and that dnKif3a expression in these cells ablated ciliogenesis. Interestingly, unmodified and dnKif3a-expressing cell lines displayed differential sensitivities and pathway activation to SHH and variable tumor-associated survival following mouse xenografts. In one cell line, SHH-induced cell proliferation was prevented in vitro by either expressing dnKif3a or inhibiting SMO signaling using cyclopamine, and the survival times of mice implanted with dnKif3a-expressing cells were increased. In a second line, expression of dnKif3a increased the cells' baseline proliferation while, surprisingly, sensitizing them to SHH-induced cell death. The survival times of mice implanted with these dnKif3a-expressing cells were decreased. Finally, expression of dnKif3a in a third cell line had no effect on cell proliferation, SHH sensitivity, or mouse survival times. These findings indicate that KIF3A is essential for GBM cell ciliogenesis, but its role in modulating GBM cell behavior is highly variable.

Kaur G, Reinhart RA, Monks A, et al.
Bromodomain and hedgehog pathway targets in small cell lung cancer.
Cancer Lett. 2016; 371(2):225-39 [PubMed] Free Access to Full Article Related Publications
Small cell lung cancer (SCLC) is an extremely aggressive cancer that frequently recurs. Twenty-three human SCLC lines were selected representing varied Myc status. Gene expression of lung cancer, stem-like, hedgehog pathway, and notch pathway genes were determined by RT(2)-PCR array and Exon 1.0 ST array. Etoposide and topotecan concentration response was examined. The IC50's for etoposide and topotecan ranged over nearly 3 logs upon 96 hrs exposure to the drugs. Myc status, TOP2A, TOP2B and TOP1 mRNA expression or topoisomerase 1 and topoisomerase 2 protein did not account for the range in the sensitivity to the drugs. γ-secretase inhibitors, RO429097 and PF-03084014, had little activity in the SCLC lines over ranges covering the clinical Cmax concentrations. MYC amplified lines tended to be more sensitive to the bromodomain inhibitor JQ1. The Smo antagonists, erismodegib and vismodegib and the Gli antagonists, HPI1 and SEN-450 had a trend toward greater sensitivity of the MYC amplified line. Recurrent SCLC is among the most recalcitrant cancers and drug development efforts in this cancer are a high priority.

Briffa R, Um I, Faratian D, et al.
Multi-Scale Genomic, Transcriptomic and Proteomic Analysis of Colorectal Cancer Cell Lines to Identify Novel Biomarkers.
PLoS One. 2015; 10(12):e0144708 [PubMed] Free Access to Full Article Related Publications
Selecting colorectal cancer (CRC) patients likely to respond to therapy remains a clinical challenge. The objectives of this study were to establish which genes were differentially expressed with respect to treatment sensitivity and relate this to copy number in a panel of 15 CRC cell lines. Copy number variations of the identified genes were assessed in a cohort of CRCs. IC50's were measured for 5-fluorouracil, oxaliplatin, and BEZ-235, a PI3K/mTOR inhibitor. Cell lines were profiled using array comparative genomic hybridisation, Illumina gene expression analysis, reverse phase protein arrays, and targeted sequencing of KRAS hotspot mutations. Frequent gains were observed at 2p, 3q, 5p, 7p, 7q, 8q, 12p, 13q, 14q, and 17q and losses at 2q, 3p, 5q, 8p, 9p, 9q, 14q, 18q, and 20p. Frequently gained regions contained EGFR, PIK3CA, MYC, SMO, TRIB1, FZD1, and BRCA2, while frequently lost regions contained FHIT and MACROD2. TRIB1 was selected for further study. Gene enrichment analysis showed that differentially expressed genes with respect to treatment response were involved in Wnt signalling, EGF receptor signalling, apoptosis, cell cycle, and angiogenesis. Stepwise integration of copy number and gene expression data yielded 47 candidate genes that were significantly correlated. PDCD6 was differentially expressed in all three treatment responses. Tissue microarrays were constructed for a cohort of 118 CRC patients and TRIB1 and MYC amplifications were measured using fluorescence in situ hybridisation. TRIB1 and MYC were amplified in 14.5% and 7.4% of the cohort, respectively, and these amplifications were significantly correlated (p≤0.0001). TRIB1 protein expression in the patient cohort was significantly correlated with pERK, Akt, and Caspase 3 expression. In conclusion, a set of candidate predictive biomarkers for 5-fluorouracil, oxaliplatin, and BEZ235 are described that warrant further study. Amplification of the putative oncogene TRIB1 has been described for the first time in a cohort of CRC patients.

Wu C, Cheng J, Hu S, et al.
Reduced proliferation and increased apoptosis of the SGC‑7901 gastric cancer cell line on exposure to GDC‑0449.
Mol Med Rep. 2016; 13(2):1434-40 [PubMed] Related Publications
The sonic hedgehog (Shh) pathway is known to be vital in embryonic development and cancer propagation due to its irreplaceable role in cell proliferation and differentiation. GDC‑0449, a basal cell skin cancer target drug approved by the Food and Drugs Administration, is a smoothened (Smo)-specific antagonist. Although it has been clinically verified as a valid drug for the treatment of skin and pancreatic cancer, the application of GDC‑0449 in gastric cancer requires further investigation. In the present study, high-glucose Dulbecco's modified Eagle's medium with 10% fetal bovine serum was used for routine SGC‑7901 cell line culture. A Cell Counting Kit‑8 assay was employed for determination of the reproductive rate of the cells. Flow cytometry was performed to determine the apoptosis status of the SGC‑7901 cell line through Q4 analysis. Reverse transcription-quantitative polymerase chain reaction and Western blot analyses were used as target molecule detection vehicles. As expected, GDC‑0449 reduced the expression levels of Shh‑associated molecules, including Smo and gli1, compared with the blank group. The rate of cell proliferation was markedly limited and was accompanied by an increase in the apoptotic rate following GDC‑0449 exposure. In addition, further investigations confirmed B cell lymphoma‑2 (Bcl‑2) as the downstream molecular mechanism of GDC‑0449 efficacy. Of note, representatives of the cancer stem cell (CSC) surface marker, CD44 and CD133, demonstrated a similar trend to the Smo restriction observed. By repressing the expression of Bcl‑2, GDC‑0449 inhibited the normal proliferation of SGC‑7901 cells, and accelerated the apoptotic rate of the cells. It may also alter CSC properties due to the reduction in the expression of surface markers.

Onishi H, Yamasaki A, Kawamoto M, et al.
Hypoxia but not normoxia promotes Smoothened transcription through upregulation of RBPJ and Mastermind-like 3 in pancreatic cancer.
Cancer Lett. 2016; 371(2):143-50 [PubMed] Related Publications
We previously demonstrated that Hedgehog (Hh) signaling is activated under hypoxia through upregulation of transcription of Smoothened (SMO) gene. However, the mechanism of hypoxia-induced activation of SMO transcription remains unclear. In the analysis of altered expressions of genes related to Hh signaling between under normoxia and hypoxia by DNA microarray analysis, we picked up 2 genes, a transcriptional regulator, recombination signal binding protein for immunoglobulin-kappa-J region (RBPJ) and a transcriptional co-activator, Mastermind-like 3 (MAML3). Expressions of SMO, MAML3 and RBPJ were increased under hypoxia in pancreatic ductal adenocarcinoma cells (PDAC). RBPJ and MAML3 inhibition under hypoxia led to decreased SMO and GLI1 expressions, whereas SMO expression in MAML3-inhibited and RBPJ-inhibited cells under normoxia showed no change. However, overexpression of RBPJ under normoxia led to increased SMO expression. Additionally, cells knocked down for MAML3 and RBPJ inhibition under hypoxia showed decreased invasiveness through matrix metalloproteinase-2 suppression and decreased proliferation. Xenograft mouse models showed that MAML3 and RBPJ knockdown inhibited tumorigenicity and tumor volume. Our results suggest that hypoxia promotes SMO transcription through upregulation of MAML3 and RBPJ to induce proliferation, invasiveness and tumorigenesis in pancreatic cancer.

Vollbrecht C, Werner R, Walter RF, et al.
Mutational analysis of pulmonary tumours with neuroendocrine features using targeted massive parallel sequencing: a comparison of a neglected tumour group.
Br J Cancer. 2015; 113(12):1704-11 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Lung cancer is the leading cause of cancer-related deaths worldwide. The typical and atypical carcinoid (TC and AC), the large-cell neuroendocrine carcinoma (LCNEC) and the small-cell lung cancers (SCLC) are subgroups of pulmonary tumours that show neuroendocrine differentiations. With the rising impact of molecular pathology in routine diagnostics the interest for reliable biomarkers, which can help to differentiate these subgroups and may enable a more personalised treatment of patients, grows.
METHODS: A collective of 70 formalin-fixed, paraffin-embedded (FFPE) pulmonary neuroendocrine tumours (17 TCs, 17 ACs, 19 LCNECs and 17 SCLCs) was used to identify biomarkers by high-throughput sequencing. Using the Illumina TruSeq Amplicon-Cancer Panel on the MiSeq instrument, the samples were screened for alterations in 221 mutation hot spots of 48 tumour-relevant genes.
RESULTS: After filtering >26 000 detected variants by applying strict algorithms, a total of 130 mutations were found in 29 genes and 49 patients. Mutations in JAK3, NRAS, RB1 and VHL1 were exclusively found in SCLCs, whereas the FGFR2 mutation was detected in LCNEC only. KIT, PTEN, HNF1A and SMO were altered in ACs. The SMAD4 mutation corresponded to the TC subtype. We prove that the frequency of mutations increased with the malignancy of tumour type. Interestingly, four out of five ATM-mutated patients showed an additional alteration in TP53, which was by far the most frequently altered gene (28 out of 130; 22%). We found correlations between tumour type and IASLC grade for ATM- (P=0.022; P=0.008) and TP53-mutated patients (P<0.001). Both mutated genes were also associated with lymph node invasion and distant metastasis (P⩽0.005). Furthermore, PIK3CA-mutated patients with high-grade tumours showed a reduced overall survival (P=0.040) and the mutation frequency of APC and ATM in high-grade neuroendocrine lung cancer patients was associated with progression-free survival (PFS) (P=0.020).
CONCLUSIONS: The implementation of high-throughput sequencing for the analysis of the neuroendocrine lung tumours has revealed that, even if these tumours encompass several subtypes with varying clinical aggressiveness, they share a number of molecular features. An improved understanding of the biology of neuroendocrine tumours will offer the opportunity for novel approaches in clinical management, resulting in a better prognosis and prediction of therapeutic response.

Lesiak A, Sobolewska-Sztychny D, Majak P, et al.
Relation between sonic hedgehog pathway gene polymorphisms and basal cell carcinoma development in the Polish population.
Arch Dermatol Res. 2016; 308(1):39-47 [PubMed] Related Publications
In recent decades, increases have been observed in the incidence of nonmelanoma skin cancers, including basal cell carcinoma (BCC) and squamous cell carcinoma. BCC is the most common neoplasm in Caucasian populations. Sonic hedgehog (Shh) pathway impairment plays a key role in BCC pathogenesis, and there is evidence that Shh pathway genetic variations may predispose to BCC development. We genotyped 22 single-nucleotide polymorphisms (SNPs) in 4 Shh pathway genes: SHH, GLI, SMO, and PTCH. The study group consisted of 142 BCC patients and 142 age-matched, sex-matched healthy subjects (controls). SNPs were assessed using the PCR-RFLP method. The genotype distribution for the polymorphisms in the rs104894049 331 A/T SHH, rs104894040 349 T/C SHH, and rs41303402 385 G/A SMO genes differed significantly between the BCC patients and the controls. The presence of CC genotype in the SHH rs104894040 349 T/C polymorphism was linked to the highest risk of BCC development (OR 87.9, p < 0.001). Other genotypes, such as the TT in SHH rs104894049 331 A/T and the GG in SMO rs41303402 385 G/A also statistically raised the risk of BCC, but these associations were weaker. Other investigated polymorphisms showed no statistical differences between patients and controls. The results obtained testify to the importance of the SHH and SMO gene polymorphisms in skin cancerogenesis. These results mainly underline the potential role of SHH3 rs104894040 349 T/C gene polymorphism in the development of skin basal cell carcinomas in patients of Polish origin.

Zhou J, Zhu G, Huang J, et al.
Non-canonical GLI1/2 activation by PI3K/AKT signaling in renal cell carcinoma: A novel potential therapeutic target.
Cancer Lett. 2016; 370(2):313-23 [PubMed] Related Publications
Renal cell carcinoma (RCC) is the most lethal urologic malignancy; however, the molecular events supporting RCC carcinogenesis and progression remain poorly understood. In this study, based on the analysis of gene expression profile data from human clear cell RCC (ccRCC) and the corresponding normal tissues, we discovered that Hedgehog (HH) pathway component genes GLI1 and GLI2 were significantly elevated in ccRCC. Survival analysis of a large cohort of ccRCC samples demonstrated that the expression of GLI1 and GLI2 was negatively correlated with patient overall survival. Clinical sample-based VHL mutation and cell model-based VHL manipulation studies all indicated that the activation of GLI1 and GLI2 was not affected by VHL status. Further signaling pathway dissections demonstrated that GLI1 and GLI2 were activated by the phosphoinositide 3-kinase (PI3K)/AKT pathway, but not mediated by the canonical HH/SMO/GLI signaling. Up-regulation of GLI1 and GLI2 promoted RCC proliferation and clonogenic ability, whereas, a combination of GLIs inhibitor Gant61 and AKT inhibitor Perifosine synergistically suppressed RCC growth and induced apoptosis in vitro and in vivo. Therefore, this study identifies that GLI1 and GLI2 are critical for RCC carcinogenesis, and also provides an alternative therapeutic strategy for RCC.

Han B, Qu Y, Jin Y, et al.
FOXC1 Activates Smoothened-Independent Hedgehog Signaling in Basal-like Breast Cancer.
Cell Rep. 2015; 13(5):1046-58 [PubMed] Free Access to Full Article Related Publications
The mesoderm- and epithelial-mesenchymal transition-associated transcription factor FOXC1 is specifically overexpressed in basal-like breast cancer (BLBC), but its biochemical function is not understood. Here, we demonstrate that FOXC1 controls cancer stem cell (CSC) properties enriched in BLBC cells via activation of Smoothened (SMO)-independent Hedgehog (Hh) signaling. This non-canonical activation of Hh is specifically mediated by Gli2. Furthermore, we show that the N-terminal domain of FOXC1 (aa 1-68) binds directly to an internal region (aa 898-1168) of Gli2, enhancing the DNA-binding and transcription-activating capacity of Gli2. FOXC1 expression correlates with that of Gli2 and its targets in human breast cancers. Moreover, FOXC1 overexpression reduces sensitivity to anti-Hedgehog (Hh) inhibitors in BLBC cells and xenograft tumors. Together, these findings reveal FOXC1-mediated non-canonical Hh signaling that determines the BLBC stem-like phenotype and anti-Hh sensitivity, supporting inhibition of FOXC1 pathways as potential approaches for improving BLBC treatment.

Tibes R, Al-Kali A, Oliver GR, et al.
The Hedgehog pathway as targetable vulnerability with 5-azacytidine in myelodysplastic syndrome and acute myeloid leukemia.
J Hematol Oncol. 2015; 8:114 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Therapy and outcome for elderly acute myeloid leukemia (AML) patients has not improved for many years. Similarly, there remains a clinical need to improve response rates in advanced myelodysplastic syndrome (MDS) patients treated with hypomethylating agents, and few combination regimens have shown clinical benefit. We conducted a 5-azacytidine (5-Aza) RNA-interference (RNAi) sensitizer screen to identify gene targets within the commonly deleted regions (CDRs) of chromosomes 5 and 7, whose silencing enhances the activity of 5-Aza.
METHODS AND RESULTS: An RNAi silencing screen of 270 genes from the CDRs of chromosomes 5 and 7 was performed in combination with 5-Aza treatment in four AML cell lines (TF-1, THP-1, MDS-L, and HEL). Several genes within the hedgehog pathway (HhP), specifically SHH, SMO, and GLI3, were identified as 5-Aza sensitizing hits. The smoothened (SMO) inhibitors LDE225 (erismodegib) and GDC0449 (vismodegib) showed moderate single-agent activity in AML cell lines. Further studies with erismodegib in combination with 5-Aza demonstrated synergistic activity with combination index (CI) values of 0.48 to 0.71 in seven AML lines. Clonogenic growth of primary patient samples was inhibited to a greater extent in the combination than with single-agent erismodegib or 5-Aza in 55 % (6 of 11) primary patient samples examined. There was no association of the 5-Aza/erismodegib sensitization potential to clinical-cytogenetic features or common myeloid mutations. Activation of the HhP, as determined by greater expression of HhP-related genes, showed less responsiveness to single-agent SMO inhibition, while synergy between both agents was similar regardless of HhP gene expression. In vitro experiments suggested that concurrent dosing showed stronger synergy than sequential dosing.
CONCLUSIONS: Inhibition of the HhP with SMO inhibitors in combination with the hypomethylating agent 5-Aza demonstrates synergy in vitro and inhibits long-term repopulation capacity ex vivo in AML and MDS. A clinical trial combining 5-Aza with LDE225 (erismodegib) in MDS and AML is ongoing based on these results as well as additional publications suggesting a role for HhP signaling in myeloid disease.

Pino LC, Balassiano LK, Sessim M, et al.
Basal cell nevus syndrome: clinical and molecular review and case report.
Int J Dermatol. 2016; 55(4):367-75 [PubMed] Related Publications
Basal cell nevus syndrome (BCNS), also referred to as nevoid basal cell carcinoma syndrome or Gorlin-Goltz syndrome, was first described by Gorlin and Goltz in 1960 as an autosomal dominant disorder characterized by the early appearance of multiple basal cell carcinomas (BCCs), keratocysts of the jaw, ectopic calcifications, palmar and plantar pits, and anomalies of the ocular, skeletal, and reproductive systems. The genesis of this cancer's etiology in relation to BCNS was unclear until a few years ago when molecular analysis studies suggested a relationship between BCC and the loss-of-function mutations of the patched gene (PTCH) found on chromosome arm 9q. PTCH inhibits signaling by the membrane protein Smoothened (Smo), and this inhibition is relieved by binding sonic hedgehog (SHH) to PTCH. We describe a patient with multiple BCCs associated with x-ray anomalies of BCNS and review the basis of the SHH signaling pathway and clinical aspects of BCNS.

Bhatia S, Hirsch K, Baig NA, et al.
Effects of altered ephrin-A5 and EphA4/EphA7 expression on tumor growth in a medulloblastoma mouse model.
J Hematol Oncol. 2015; 8:105 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Members of the Eph/ephrin gene families act as key regulators of cerebellar development during embryogenesis. Aberrant signaling of Eph family of receptor tyrosine kinases and their ephrin ligands has also been implicated in human cancers. Medulloblastoma is an aggressive primitive neuroectodermal tumor that originates from granule neuron precursors in the cerebellum. Previous studies have suggested a role for the ephrin-A5 ligand and its receptors, EphA4 and EphA7, in granule cell-precursor formation and in guiding cell migration. In the present study, we investigated the effects of genetic loss of ephrin-A5, EphA4, and EphA7 on the spatiotemporal development of medulloblastoma tumors in the context of the smoothened transgenic mouse model system.
FINDINGS: Radiographic magnetic resonance imaging (MRI) was performed to monitor tumor growth in a genetically engineered mouse model of medulloblastoma. Tumor tissue was harvested to determine changes in the expression of phosphorylated Akt by Western blotting. This helped to establish a correlation between genotype and/or tumor size and survival. Our in vivo data establish that in ND2-SmoA1 transgenic mice, the homozygous deletion of ephrin-A5 resulted in a consistent pattern of tumor growth inhibition compared to their ephrin-A5 wild-type littermate controls, while the loss of EphA4/EphA7 failed to produce consistent effects versus EphA4/EphA7 wild-type mice. A positive correlation was evident between tumor size, p-Akt, and proliferating cell nuclear antigen (PCNA) expression in our transgenic mouse model system, regardless of genotype.
CONCLUSIONS: Taken together, our findings underscore the importance of targeting specific members of the Eph/ephrin families in conjunction with the Akt pathway in order to inhibit medulloblastoma tumor growth and progression.

Pelosi G, Fabbri A, Papotti M, et al.
Dissecting Pulmonary Large-Cell Carcinoma by Targeted Next Generation Sequencing of Several Cancer Genes Pushes Genotypic-Phenotypic Correlations to Emerge.
J Thorac Oncol. 2015; 10(11):1560-9 [PubMed] Related Publications
INTRODUCTION: Little is known about genotypic and phenotypic correlations in undifferentiated large-cell carcinoma (LCC) of the lung.
METHODS: Thirty LCC were dissected by unsupervised targeted next generation sequencing analysis for 50 cancer-associated oncogenes and tumor suppressor genes. Cell differentiation lineages were unveiled by using thyroid transcription factor-1 (TTF1) for adenocarcinoma (ADC) and p40 for squamous cell carcinoma (SQC), dichotomizing immunohistochemistry (IHC) results for TTF1 as negative or positive (whatever its extent) and for p40 as negative, positive, or focal (if <10% of reactive tumor cells).
RESULTS: Three LCC were wild type (all TTF1+/p40-), whereas the remaining 27 (90%) tumors had at least one gene mutation. Twenty-four cases featuring TTF1+/p40-, TTF1+/p40±, TTF1-/p40±, or TTF1-/p40- phenotypes comprised ATM, BRAF, CDKN2A, EGFR, ERBB4, FBXW7, FLT3, KRAS, NRAS, PIK3CA, PTPN11, RET, SMAD4, SMO, STK11, or TP53 mutations in keeping with ADC lineage, whereas three tumors showing TTF1-/p40+ phenotype harbored TP53 only and no ADC-related mutations in keeping with SQC lineage. Single, double, triple, quadruple, and quintuple mutations occurred in 16, 6, 2, 2, and 1 patient, respectively. The occurrence of three mutations or more but not any immunohistochemistry categorization predicted shorter overall survival (OS, p = 0.001) and disease-free survival (DFS, p = 0.007), independent of age, sex, and tumor stage.
CONCLUSIONS: Albeit preliminary also because of the relatively small number of LCC under evaluation, this targeted next generation sequencing study, however, revealed gene mutation heterogeneity in LCC with some genotypic-phenotypic correlations. Negativity or focal occurrence of p40 made SQC diagnosis unlikely on molecular grounds, but suggested ADC confirming validity of the axiom "no p40, no squamous."

Lee SJ, Litan A, Li Z, et al.
Na,K-ATPase β1-subunit is a target of sonic hedgehog signaling and enhances medulloblastoma tumorigenicity.
Mol Cancer. 2015; 14:159 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The Sonic hedgehog (Shh) signaling pathway plays an important role in cerebellar development, and mutations leading to hyperactive Shh signaling have been associated with certain forms of medulloblastoma, a common form of pediatric brain cancer. While the fundamentals of this pathway are known, the molecular targets contributing to Shh-mediated proliferation and transformation are still poorly understood. Na,K-ATPase is a ubiquitous enzyme that maintains intracellular ion homeostasis and functions as a signaling scaffold and a cell adhesion molecule. Changes in Na,K-ATPase function and subunit expression have been reported in several cancers and loss of the β1-subunit has been associated with a poorly differentiated phenotype in carcinoma but its role in medulloblastoma progression is not known.
METHODS: Human medulloblastoma cell lines and primary cultures of cerebellar granule cell precursors (CGP) were used to determine whether Shh regulates Na,K-ATPase expression. Smo/Smo medulloblastoma were used to assess the Na,K-ATPase levels in vivo. Na,K-ATPase β1-subunit was knocked down in DAOY cells to test its role in medulloblastoma cell proliferation and tumorigenicity.
RESULTS: Na,K-ATPase β1-subunit levels increased with differentiation in normal CGP cells. Activation of Shh signaling resulted in reduced β1-subunit mRNA and protein levels and was mimicked by overexpression of Gli1and Bmi1, both members of the Shh signaling cascade; overexpression of Bmi1 reduced β1-subunit promoter activity. In human medulloblastoma cells, low β1-subunit levels were associated with increased cell proliferation and in vivo tumorigenesis.
CONCLUSIONS: Na,K-ATPase β1-subunit is a target of the Shh signaling pathway and loss of β1-subunit expression may contribute to tumor development and progression not only in carcinoma but also in medulloblastoma, a tumor of neuronal origin.

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