Patched Gene Research Articles

Gorlin-Goltz Syndrome with Multiple OKC in a 10-Year-Old Child: A Case Report

Gorlin-Goltz syndrome is rare multi-system disease, which is, characterized by neoplasms and other developmental abnormalities. 1 It is a hereditary condition inherited as an autosomal dominant trait and caused by abnormalities in the PTCH1 (Patched1) gene which is traced to the long arm of chromosome 9q22.3-q31. It is characterized by the triad of multiple baso-cellular epitheliomas, odontogenic keratocysts (OKC) in the jaws and skeletal anomalies. Early diagnosis and treatment are important for long-term prognosis of the syndrome by reducing the severity of cutaneous carcinomas and deformities due to jaw cyst. Current case discusses a 10-year-old child suffering from Gorlin-Goltz syndrome, this case report emphasizes on early diagnosis and prompt treatment of such case. Keywords OKC, Gorlin-Goltz syndrome, Multi nodular radiolucency

The effect of ginger extract on expression of Gli1 and Patched-1 genes involved in breast cancer signaling pathway under in vitro condition

Introduction and Aim: Breast cancer ranks among the leading causes of death in women worldwide. Ginger has shown potential efficacy against certain cancer types, surpassing conventional therapies such as chemotherapy and radiation. However, its molecular mechanisms remain less understood. Materials and Methods: In this study, MCF-7 cancer cells were cultured and treated with various concentrations of aqueous ginger extract (20, 30, 45, 65 microgram/mL) for 12, 48, and 72 hours. The effects were assessed through gene expression analysis and cell vitality assays (MTT). Results: The cell vitality test revealed a direct correlation between cytotoxicity and extract concentration. Concentrations exceeding 30 microgram/mL exhibited significant cell death (IC50 of 104.03 microgram/mL). Gene expression analysis demonstrated an increase in Patched-1 and a decrease in Gli1 expression with rising extract concentrations. The maximum Patched-1 expression occurred at 65 microgram/mL after 72 hours. Patched-1 (oncogene) and Gli1 (tumor suppressor) are pivotal genes in the hedgehog (Hh) signalling pathway associated with breast cancer. Conclusion: It appears that ginger compounds play a substantial role in regulating cancer progression by influencing key components of the hedgehog signalling pathway.

Gorlin-Goltz Syndrome: A Case Report and Literature Review with PTCH1 Gene Sequencing.

Gorlin-Goltz syndrome, also known as nevoid basal cell carcinoma syndrome, is an autosomal dominant disease characterized by multisystemic developmental defects caused by pathogenic variants such as patched-1 ( PTCH1 ) gene variants and/or SUFU gene variants. The presence of either two main criteria or one major and two minor criteria are required for the diagnosis of Gorlin-Goltz syndrome. Recently, a major criterion for molecular confirmation has also been proposed. In this article, we report the case of an 80-year-old male who was admitted at our department for multiple brown-to-black papules and plaques on the entire body. He was diagnosed with Gorlin-Goltz syndrome with clinical, radiologic, and pathologic findings. While the diagnosis was made based on the clinical findings in general, confirmation of the genetic variants makes an ideal diagnosis and suggests a new treatment method for target therapy. We requested a genetic test of PTCH1 to ideally identify the molecular confirmation in the hedgehog signaling pathway. However, no pathogenic variants were found in the coding region of PTCH1, and no molecular confirmation was achieved.

Whole-Exome Sequencing Identified Two Novel Pathogenic Mutations in the PTCH1 Gene in BCNS.

Basal cell nevus syndrome (BCNS, OMIM 109400) is a familial cancer syndrome characterized by the development of numerous basal cell cancers and various other developmental abnormalities, including epidermal cysts of the skin, calcified dural folds, keratocysts of the jaw, palmar and plantar pits, ovarian fibromas, medulloblastomas, lymphomesenteric cysts, and fetal rhabdomyomas. BCNS shows autosomal dominant inheritance and is caused by mutations in the patched 1 (PTCH1) gene and the suppressor of the fused homolog (SUFU) gene. In a few cases, variants of patched 2 (PTCH2) have been found in patients who met the criteria for BCNS. In an investigation of 11 Hungarian families who fulfilled the diagnostic criteria for BCNS, whole-exome sequencing (WES) and multiplex ligation-dependent probe amplification (MLPA) identified two novel pathogenic variants (c.2994C>A; p.Cys998Ter and c.814_818del; p.Asn272SerfsTer11), one recently identified variant (c.1737_1745del p.Val580_Val582del), and three recurrent disease-causing variants of the PTCH1 gene with a diagnosis rate of 63.6%. Disease-causing variants were not found for the SUFU and PTCH2 genes. These applied methods could not fully elucidate the genetic background of all the BCNS cases that we investigated. To uncover the missing heritability of BCNS, whole-genome sequencing or an epigenetic approach might be considered in the future.

Expression of PTCH gene in ameloblastoma and odontogenic keratocyst: A comparative study.

This is a cross-sectional comparative study, aimed to quantify the expression of patched (PTCH) gene in ameloblastoma, odontogenic keratocyst (OKC) and also the comparison of both the expressions. Genomic deoxyribonucleic acid (DNA) was extracted and quantified, and the expression of the PTCH gene was done in 17 cases of ameloblastoma and 17 cases of OKC by quantitative real-time polymerase chain reaction (RT-qPCR). It was observed that there was an overexpression of the PTCH gene in both ameloblastoma and OKC with a good mean cycle threshold (CT) value of 32.71 ± 2.432 and 34.69 ± 1.875, respectively. When comparing the PTCH expression between the two, ameloblastoma showed higher expression than the OKC and the difference is statistically significant with P value of 0.025. Our findings suggest that there is overexpression of PTCH in ameloblastoma and OKC, but it is highly expressed in ameloblastoma when compared to OKC. Overexpression of PTCH may constitute the activation of the Sonic Hedgehog pathway and may suggest the mechanism for the development of ameloblastoma and OKC. Hence it can be used as a valuable marker for early diagnosis and in the identification of therapeutic targets.

A patched1 gene homologue participates in female differentiation of Cynoglossus semilaevis

Patched (Ptch) is a receptor in the hedgehog signaling pathway, essential for animal development. Our previous study showed that ptch1 gene participates in the maintenance of the male germline and spermatogenesis in Cynoglossus semilaevis (csptch1). In this study, we identified a patched1 gene homolog (csptch1 x1). The csptch1 x1 gene is 5761 bp long, with a 4638 bp coding sequence that encodes 1545 amino acids. The Csptch1 x1 protein has 12 transmembrane regions and sterol-sensing domains and is highly homologous to the csptch1 (91 amino acids difference). Expression pattern analysis showed that csptch1 x1 is expressed in eight different tissues of adult tongue sole, and the expression is significantly higher in tissues of female than that in male tissues. The expression pattern in developmental stages was also analyzed. csptch1 x1 could be detected at the 1-cell stage and was highly expressed at the blastocyst, somite, and blastopore closing stages, implying that it participates in cell differentiation. In ovarian development, the expression of csptch1 x1 was initiated at 20 days after hatching (dah) and was significantly high at 35–50 and 95–150 dah. In situ hybridization showed that csptch1 x1 was predominantly expressed in primordial germ cells, oocytes, and follicular cells, but the expression of the gene was lower in the testis. These results suggest that csptch1 x1 may be mainly involved in female differentiation and ovarian development, different from the role of csptch1 in spermatogenesis.

Retrospective analysis of the histopathologic features of basal cell carcinomas in pediatric patients with basal cell nevus syndrome.

Basal cell nevus syndrome (BCNS) is an autosomal dominant condition caused most often by a loss-of-function mutation in the Patched-1 (PTCH1) gene. It is characterized by the development of varied benign and malignant tumors, including numerous cutaneous basal cell carcinomas (BCCs). The PTCH1 gene is integral in hair follicle development and loss of function mutation may lead to BCCs with an infundibulocystic histopathology in BCNS patients. Few studies have described the histopathological features of BCCs in BCNS. The recognition of these histopathologic features by dermatologists, dermatopathologists, and others caring for children will allow earlier and more effective identification of BCNS. We performed a retrospective analysis of 25 BCCs in 11 patients aged 5 to 19 years with BCNS and evaluated the histopathologic features on hematoxylin-eosin-stained sections. Our study found that 80% of BCCs in BCNS patients occurred on the head and neck with 64% of the specimens demonstrating infundibulocystic differentiation. Infundibulocystic differentiation is a common finding in BCCs found in BCNS. The finding of cutaneous neoplasms consistent with BCC with infundibulocystic differentiation in children is common in pediatric patients with BCNS and can be considered to be an early marker of the disorder, prompting further clinical investigation.

Patched 1 expression in Merkel cell carcinoma.

The relevance of Hedgehog signaling in Merkel cell carcinoma has only been addressed by a few studies with conflicting results. Thus, we aimed to establish the expression of Hedgehog signaling molecules in Merkel cell carcinoma to characterize causes of aberrant expression and to correlate these findings with the clinical course of the patients. Immunohistochemistry was performed for Sonic, Indian, Patched 1 (PTCH1) and Smoothened on patients' tumor tissue. Respective mRNA expression was analyzed in 10 Merkel cell carcinoma cell lines using quantitative real-time polymerase chain reaction. PTCH1 sequencing and DNA methylation microarray analyses were carried out on tumor tissues as well as cell lines. PTCH1 immunoreactivity in Merkel cell carcinoma was similar to that of basal cell carcinomas, which both significantly differed from PTCH1 immunoreactivity in healthy skin. Most PTCH1 mutations found were synonymous or without known functional impact. However, on average, the promoter regions of both PTCH1 were hypomethylated independently from PTCH1 gene expression or Merkel cell polyomavirus status. PTCH1 and GLI1/2/3 genes were differently expressed in different cell lines; notably, there was a significant correlation between GLI2 and PTCH1 mRNA expression. Similar to PTCH1 protein expression in patient tissues, PTCH1 gene expression in Merkel cell carcinoma cell lines is highly variable, but due to the similar methylation pattern across Merkel cell carcinoma cell lines, effects other than methylation seem to be the reason for the differential expression and PTCH1 appears to be upregulated by GLI as a classical Hedgehog target gene.

Identification of rare PTCH1 nonsense variant causing orofacial cleft in a Chinese family and an up-to-date genotype-phenotype analysis

The Patched 1 (PTCH1) gene encodes a membrane receptor involved in the Hedgehog (Hh) signaling pathway, an abnormal state of which may result in congenital defects or human tumors. In this study, we conducted whole-exome sequencing on a three-generation Chinese family characterized with variable penetrance of orofacial clefts. A rare heterozygous variant in the PTCH1 gene (c.2833C > T p.R945X) was identified as a disease-associated mutation. Structural modeling revealed a truncation starting from the middle of the second extracellular domain of PTCH1 protein. This may damage its ligand recognition and sterol transportation abilities, thereby affecting the Hh signaling pathway. Biochemical assays indicated that the R945X protein had reduced stability compared to the wild-type in vitro. In addition, we reviewed the locations and mutation types of PTCH1 variants in individuals with clefting phenotypes, and analyzed the associations between clefts and locations or types of variants within PTCH1. Our findings provide further evidence that PTCH1 variants result in orofacial clefts, and contributed to genetic counseling and clinical surveillance in this family.

New mutations and an updated database for the patched-1 (PTCH1) gene.

BackgroundBasal cell nevus syndrome (BCNS) is an autosomal dominant disorder characterized by multiple basal cell carcinomas (BCCs), maxillary keratocysts, and cerebral calcifications. BCNS most commonly is caused by a germline mutation in the patched‐1 (PTCH1) gene. PTCH1 mutations are also described in patients with holoprosencephaly.MethodsWe have established a locus‐specific database for the PTCH1 gene using the Leiden Open Variation Database (LOVD). We included 117 new PTCH1 variations, in addition to 331 previously published unique PTCH1 mutations. These new mutations were found in 141 patients who had a positive PTCH1 mutation analysis in either the VU University Medical Centre (VUMC) or Maastricht University Medical Centre (MUMC) between 1995 and 2015.ResultsThe database contains 331 previously published unique PTCH1 mutations and 117 new PTCH1 variations.ConclusionWe have established a locus‐specific database for the PTCH1 gene using the Leiden Open Variation Database (LOVD). The database provides an open collection for both clinicians and researchers and is accessible online at http://www.lovd.nl/PTCH1.

Multi-layered mutation in hedgehog-related genes in Gorlin syndrome may affect the phenotype.

Gorlin syndrome is a genetic disorder of autosomal dominant inheritance that predisposes the affected individual to a variety of disorders that are attributed largely to heterozygous germline patched1 (PTCH1) mutations. PTCH1 is a hedgehog (Hh) receptor as well as a repressor, mutation of which leads to constitutive activation of Hh pathway. Hh pathway encompasses a wide variety of cellular signaling cascades, which involve several molecules; however, no associated genotype–phenotype correlations have been reported. Recently, mutations in Suppressor of fused homolog (SUFU) or PTCH2 were reported in patients with Gorlin syndrome. These facts suggest that multi-layered mutations in Hh pathway may contribute to the development of Gorlin syndrome. We demonstrated multiple mutations of Hh-related genes in addition to PTCH1, which possibly act in an additive or multiplicative manner and lead to Gorlin syndrome. High-throughput sequencing was performed to analyze exome sequences in four unrelated Gorlin syndrome patient genomes. Mutations in PTCH1 gene were detected in all four patients. Specific nucleotide variations or frameshift variations of PTCH1 were identified along with the inferred amino acid changes in all patients. We further filtered 84 different genes which are closely related to Hh signaling. Fifty three of these had enough coverage of over ×30. The sequencing results were filtered and compared to reduce the number of sequence variants identified in each of the affected individuals. We discovered three genes, PTCH2, BOC, and WNT9b, with mutations with a predicted functional impact assessed by MutationTaster2 or PolyPhen-2 (Polymorphism Phenotyping v2) analysis. It is noticeable that PTCH2 and BOC are Hh receptor molecules. No significant mutations were observed in SUFU. Multi-layered mutations in Hh pathway may change the activation level of the Hh signals, which may explain the wide phenotypic variability of Gorlin syndrome.

High throughput-targeted sequencing panel for exploring radiosensitivity associated genes in esophageal squamous cell carcinoma

Objective: To explore radiosensitivity-associated genes in esophageal squamous cell carcinoma by targeted sequencing panel. Methods: The peripheral blood from 22 esophageal squamous cell carcinoma (ESCC) patients received radiotherapy alone were collected, respectively. The genomic DNA (gDNA) of peripheral blood was extracted and used to create a library of gDNA restriction fragments. The gDNA restriction fragments were hybridized to the HaloPlex probe capture library, which comprises 356 cancer genes selected from the Catalogue of Somatic Mutations in Cancer (Cosmic) database of 2011 updated edition. The sequencing data were aligned by the Genome Analysis Toolkit GATK (version 3.0) and Picar. The single nucleotide polymorphism and inserted-deletion (SNP/InDel) variations were annotated by online database. The pathway enrichment was analyzed by Ingenuity Pathway analysis (IPA). Moreover, according to the short-period curative effect, 22 patients were divided into two groups: the radiation- sensitivity group (CR+ PR) and the radiation-resistant group (PD+ SD). The nonsynonymous mutation sites were statistically analyzed and the genes associated with radiosensitivity of ESCC were screened. Results: More than 97% sequencing reads were aligned to human genome reference sequence and more than 90% sequencing reads were the target sequences. SNP/InDel database annotation results showed that the mutations of 22 cases mainly distributed in exons, and the mutant types were mainly missense and synonymous single nucleotide variant (SNV). There were 23 genes of high-frequency mutation associated with esophageal cancer. Pathway enrichment by IPA showed that 3 pathways were associated with the development of esophageal cancer, which were roles of BRCA1 in DNA damage response pathway, DNA double-strand break repair by non-homologous end joining pathway and ATM signaling pathway. According to the curative effect, five genes including mismatch repair system component (PMS1), fibronectin 1(FN1), mutL homolog 1 (MLH1), B-Raf proto-oncogene, serine/threonine kinase (BRAF), patched 1 (PTCH1) and cytochrome P450 family 2 subfamily C member 19 (CYP2C19) were associated with radiosensitivity of ESCC patients.Moreover, the PTCH1 was mutated in all of 22 ESCC patients, while the variations of rs199476092 and rs202111971 sites of PTCH1 were only identified in the radiation-resistant group. Conclusions: We find that the variations of rs199476092 and rs202111971 in the encoding region of PTCH1 gene are significantly associated with radiosensitivity of ESCC patients.

MeCP2 Regulates PTCH1 Expression Through DNA Methylation in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease, in which pathogenesis is not clear. Many research demonstrated that fibroblast-like synoviocytes (FLSs) play a key role in RA pathogenesis, join in the cartilage injury and hyperplasia of the synovium, and contribute to the release of inflammatory cytokines. We used adjuvant arthritis (AA) rats as RA animal models. The methyl-CpG-binding protein 2 (MeCP2) enables the suppressed chromatin structure to be selectively detected in AA FLSs. Overexpression of this protein leads to an increase of integral methylation levels. Some research has confirmed the hedgehog (Hh) signaling pathway plays an important role in RA pathogenesis; furthermore, patched 1 (PTCH1) is a negative fraction of Hh signaling pathway. We used 5-aza-2'-deoxycytidine (5-azadc) as DNA methylation inhibitor. In our research, we found MeCP2 reduced PTCH1 expression in AA FLSs; 5-azadc obstructed the loss of PTCH1 expression. 5-Azadc, treatment of AA FLSs, also blocks the release of inflammatory cytokines. In order to probe the potential molecular mechanism, we assumed the epigenetic participation in the regulation of PTCH1. Results demonstrated that PTCH1 hypermethylation is related to the persistent FLS activation and inflammation in AA rats. Knockdown of MeCP2 using small-interfering RNA technique added PTCH1 expression in AA FLSs. Our results indicate that DNA methylation may offer molecule mechanisms, and the reduced PTCH1 methylation level could regulate inflammation through knockdown of MeCP2. Graphical Abstract PTCH1 is an inhibitory protein of the Hedgehog signaling pathway. Increased expression of PTCH1 can inhibit the expression of Gli1 and Shh, thereby inhibiting the activation of Hedgehog signaling pathway. Inactivated Hedgehog signaling pathway inhibits the secretion of IL-6 and TNF-α. MeCP2 mediates hypermethylation of PTCH1 gene and decreases the expression of PTCH1 protein, thus activating Hedgehog signaling pathway and increasing secretion of IL-6 and TNF-α.

Nevoid basal cell carcinoma syndrome caused by splicing mutations in the PTCH1 gene.

Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by developmental defects and tumorigenesis such as medulloblastomas and basal cell carcinomas, caused by mutations of the patched-1 (PTCH1) gene. To date, we have detected 73 mutations in PTCH1 and ten of them (14%) were suspected splicing mutations. Eight out of the ten mutations were localized near the splice donor site. Five mutations were localized within the invariant GT-AG splice site, whereas the other five mutations occurred outside the invariant GT-AG site including the last exonic nucleotide. When the transcripts were examined, all mutations resulted in aberrant splicing, including exon skipping or the activation of cryptic splice sites. This is the first extensive report of NBCCS focusing on splice site mutations, and it highlights the importance of analyzing transcripts especially for mutations lying outside the GT-AG splicing consensus site. In addition, the splice site score calculated by Splice-Site Analyzer Tool provided by Tel Aviv University helped predict aberrant splice patterns in most of the cases.

同一家系に発現した母斑基底細胞癌症候群の3例

The main stigmata of the nevoid basal cell carcinoma syndrome (NBCCS) are developmental abnormalities, including palmar or plantar pits, bifid ribs, calcification of the falx cerebri, and a high susceptibility to several neoplasms, such as basal cell carcinomas of the skin, keratocystic odontogenic tumors (KCOTs) of the jaw, and medulloblastomas. NBCCS is a hereditary disorder caused by mutations in human patched-1 gene (PTCH1) and transmitted in an autosomal dominant manner. Three cases of NBCCS in a maternal relationship are reported. We analyzed the PTCH1 gene in 2 patients (siblings) and detected identical deletion mutations (germline mutations). In patients with NBCCS, the KCOT-causing mutation is usually inherited through the germline. Thus the susceptibility to KCOT is present in every cell of the body. Consequently, KCOT associated with NBCCS shows a trend toward multiplicity. The early detection of KCOT during follow-up using computed tomography and other diagnostic imaging techniques allowed minimally invasive surgical treatment and good outcomes.

Basaloid follicular hamartoma on the upper eyelid.

Basaloid follicular hamartoma on the upper eyelid.

Establishment and characterization of a primary calcifying epithelial odontogenic tumor cell population

Calcifying epithelial odontogenic tumors (CEOTs) are rare neoplasms derived from dental tissue with the unique characteristic of calcifying amyloid-like material. To establish primary CEOT epithelial-derived cell populations, investigate the expression of enamel matrix proteins (EMPs), and identify potential ameloblastin (AMBN) and patched 1 (PTCH1) gene alterations. A 28-year-old patient with a lesion of the posterior maxilla, radiographically characterized by a radiolucency with well-defined borders containing mixed radiopacities, agreed to participate with informed consent. The patient's biopsy confirmed the diagnosis of CEOT, and a small representative tumor fragment was ascertained for cell culture. Explant cultures were established and used to establish primary cell populations. These were analyzed for morphology, cell proliferation, mineralization activity, expression of epithelial-associated markers (qRT-PCR and immunocytochemistry), and gene mutations of AMBN or PTCH1. DNA was extracted from tumor cells and gene coding and exon-intron boundaries overlapping fragments amplified. PCR products were bidirectional DNA sequenced and compared against reference sequence. A CEOT cell population was established and proliferated in culture and could be maintained for several passages. Expression of EMPs, cytokeratin 14 and 17, and patched (PTCH1), as well as ALP activity, was detected. These cells also had the ability to mineralize, similar to the primary tumor. Two AMBN alterations were identified in the sample: c.1323G>A/A441A (rs7680880) and c.1344*+111delA. Two single-nucleotide polymorphisms were identified in the PTCH1 gene. Our data support the establishment of a CEOT-derived cell population, which expresses known epithelial-associated proteins.

Common Genetic Variations in Patched1 (PTCH1) Gene and Risk of Hirschsprung Disease in the Han Chinese Population

Hirschsprung disease (HSCR) is the most frequent genetic cause of congenital intestinal obstruction with an incidence of 1:5000 live births. In a pathway-based epistasis analysis of data generated by genome-wide association study on HSCR, specific genotype of Patched 1 (PTCH1) has been linked to an increased risk for HSCR. The aim of the present study is to examine the contribution of genetic variants in PTCH1 to the susceptibility to HSCR in Han Chinese. Accordingly, we assessed 8 single nucleotide polymorphisms (SNPs) within PTCH1 gene in 104 subjects with sporadic HSCR and 151 normal controls of Han Chinese origin by the Sequenom MassArray technology (iPLEX GOLD). Two of the eight genetic markers were found to be significantly associated with Hirschsprung disease (rs357565, allele P = 0.005; rs2236405, allele P = 0.002, genotype P = 0.003). Both the C allele of rs357565 and the A allele of rs2236405 served as risk factors for HSCR. During haplotype analysis, one seven-SNP-based haplotype was the most significant, giving a global P = 0.0036. Our results firstly suggest common variations of PTCH1 may be involved in the altered risk for HSCR in the Han Chinese population, providing potential molecular markers for early diagnosis of Hirschsprung disease.

Mechanical strain disrupts primary cilia structure and modulates hedgehog signalling in adult chondrocytes

Chondrocytes are the unique cellular component of articular cartilage, the connective tissue covering the converging bone surfaces in joints. Chondrocytes within articular cartilage possess primary cilia although their function is unclear. In osteoarthritis hedgehog signalling, which takes place on the cilium, is aberrantly activated promoting cartilage degradation through the upregulation of ADAMTS5. The mechanisms for this, and the associated increase in cilia length and prevalence, are unknown. This study tests the hypothesis that alterations in mechanical loading influence cilia length and hedgehog signalling leading to increased ADAMTS-5 expression. Mature bovine articular chondrocytes were subjected to 5%, 10% or 20% cyclic tensile strain (CTS). CTS significantly reduced mean primary cilia length (p<0.05) in a dose-dependent manner such that cilia became progressively shorter with increasing strain magnitude. Indian Hedgehog gene expression was significantly increased by CTS at all strains (p<0.05). Pathway activation (Patched1 gene expression), was observed at 5% and 10% strain but not 20% strain where the greatest reductions in cilia length occurred. Similarly, the mRNA levels of ADAMTS-5 were significantly increased by CTS at 5% and 10% strain (p<0.05) but not at 20% strain. These data suggest that mechanical loading activates hedgehog signalling in adult chondrocytes promoting cartilage degradation and highlights a link between primary cilia structure and function in cartilage disease.

Combination of Hedgehog Signaling Blockage and Chemotherapy Leads to Tumor Reduction in Pancreatic Adenocarcinomas

Activation of the hedgehog signal transduction pathway, triggered by hedgehog binding to the transmembrane receptor patched 1 (PTCH1) or by mutations in the PTCH1 gene, plays an important role in the development of various tumors. To investigate whether the Hedgehog signaling pathway is also active in human pancreatic adenocarcinomas, we determined the expression levels of the known Hedgehog target genes PTCH1 and GLI-1 in pancreatic tumors. To determine whether alterations in the PTCH1 gene are responsible for this pathway activation, we screened pancreatic carcinomas for mutations in PTCH. To investigate the contribution of hedgehog signaling to the tumorigenicity of pancreatic tumor cells, we blocked the Hedgehog pathway in cultured tumor cells and xenografts using the steroidal alkaloid cyclopamine and the small-molecule Hedgehog inhibitor Hh-Antag. We identified single nucleotide polymorphisms (SNPs) within the PTCH1 gene but no somatic PTCH1 mutations. Pathway-blockage resulted in a significant dose-dependent reduction of tumor cell growth in vitro and in vivo. Moreover, combined treatment with cyclopamine and the conventional antimetabolite gemcitabine revealed a synergistic effect on the reduction of tumor growth in pancreatic adenocarcinoma xenografts. Inhibition of Hedgehog signaling could be a promising approach for the treatment of pancreatic adenocarcinomas.