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1.  Meta-analysis Reveals Genome-Wide Significance at 15q13 for Nonsyndromic Clefting of Both the Lip and the Palate, and Functional Analyses Implicate GREM1 As a Plausible Causative Gene 
PLoS Genetics  2016;12(3):e1005914.
Nonsyndromic orofacial clefts are common birth defects with multifactorial etiology. The most common type is cleft lip, which occurs with or without cleft palate (nsCLP and nsCLO, respectively). Although genetic components play an important role in nsCLP, the genetic factors that predispose to palate involvement are largely unknown. In this study, we carried out a meta-analysis on genetic and clinical data from three large cohorts and identified strong association between a region on chromosome 15q13 and nsCLP (P = 8.13×10−14 for rs1258763; relative risk (RR): 1.46, 95% confidence interval (CI): 1.32–1.61)) but not nsCLO (P = 0.27; RR: 1.09 (0.94–1.27)). The 5 kb region of strongest association maps downstream of Gremlin-1 (GREM1), which encodes a secreted antagonist of the BMP4 pathway. We show during mouse embryogenesis, Grem1 is expressed in the developing lip and soft palate but not in the hard palate. This is consistent with genotype-phenotype correlations between rs1258763 and a specific nsCLP subphenotype, since a more than two-fold increase in risk was observed in patients displaying clefts of both the lip and soft palate but who had an intact hard palate (RR: 3.76, CI: 1.47–9.61, Pdiff<0.05). While we did not find lip or palate defects in Grem1-deficient mice, wild type embryonic palatal shelves developed divergent shapes when cultured in the presence of ectopic Grem1 protein (P = 0.0014). The present study identified a non-coding region at 15q13 as the second, genome-wide significant locus specific for nsCLP, after 13q31. Moreover, our data suggest that the closely located GREM1 gene contributes to a rare clinical nsCLP entity. This entity specifically involves abnormalities of the lip and soft palate, which develop at different time-points and in separate anatomical regions.
Author Summary
Clefts of the lip and palate are common birth defects, and require long-term multidisciplinary management. Their etiology involves genetic factors and environmental influences and/or a combination of both, however, these interactions are poorly defined. Moreover, although clefts of the lip may or may not involve the palate, the determinants predisposing to specific subphenotypes are largely unknown. Here we demonstrate that variations in the non-coding region near the GREM1 gene show a highly significant association with a particular phenotype in which cleft lip and cleft palate co-occur (nsCLP; P = 8.13×10−14). Our data suggest that the risk is even higher for patients who have a cleft lip and a cleft of the soft palate, but not of the hard palate. Interestingly, this subphenotype corresponds to the expression of the mouse Grem1 gene, which is found in the developing lip and soft palate but not in the hard palate. While Grem1-deficient mice display no lip or palate defects, we demonstrate that ectopic Grem1 protein alters palatal shelve morphogenesis. Together, our results identify a region near GREM1 as the second, genome-wide significant risk locus for nsCLP, and suggest that deregulated GREM1 expression during craniofacial development may contribute to this common birth defect.
PMCID: PMC4788144  PMID: 26968009
2.  Selective inhibition of EGFR downstream signaling reverses the irradiation-enhanced migration of HNSCC cells 
American Journal of Cancer Research  2015;5(9):2660-2672.
Irradiation, which is one of the standard therapies used to treat squamous cell carcinoma of the head and neck (HNSCC), has been linked to enhanced tumor migration in carcinomas. In this study, we demonstrated that irradiation induced the phosphorylation of AKT, p38 MAPK and ERK. The combined activation of these pathways caused inactivation of GSK3β kinase, resulting in enhanced tumor cell migration. Here, we describe that the exclusive and specific inhibition of just one of the aforementioned key signaling molecules is sufficient to restore GSK3β activity and to reduce radiation-induced migration in HNSCC. These data indicate that pharmacological inhibition of pathways targeting GSK3β could decrease radiation-induced cell migration in HNSCC and thus potentially reduce metastasis and locoregional recurrence in patients.
PMCID: PMC4633896  PMID: 26609474
Radiation; migration; GSK3β
3.  Inhibition of SphK1 reduces radiation-induced migration and enhances sensitivity to cetuximab treatment by affecting the EGFR/SphK1 crosstalk 
Oncotarget  2014;5(20):9877-9888.
SphK1 is known to play a role in tumor progression, resistance to radiochemotherapy, and migration patterns. As the overall survival rates of squamous cell carcinoma of the head and neck (HNSCC) remain poor due to limitations in surgery and irradiation and chemotherapy resistance, SphK1 is an important enzyme to investigate. The purpose of this study was to elucidate the impact of SphK1 on irradiation efficacy of HNSCC in-vitro with emphasis on EGFR signaling. By immunhistochemical staining we found a positive correlation between EGFR and SphK1 expression in patient specimens. In colony formation assays irradiation sensitive cell lines showed a poor response to cetuximab, an EGFR inhibitor, and SKI-II, a SphK1 inhibitor, and vice versa. In irradiation sensitive cells an enhanced reduction of cell migration and survival was found upon simultaneous targeting of EGFR and SphK1. In the present study, we elucidated a linkage between the two signaling pathways with regard to the efficacy of cetuximab treatment and the impact on the migration behavior of tumor cells. We investigated the biological impact of inhibiting these pathways and examined the biochemical implications after different treatments. An understanding of the processes involved could help to improve the treatment of patients with HNSCC.
PMCID: PMC4259444  PMID: 25245676
SphK1; EGFR; HNSCC; radiation; radiation-induced migration
4.  The response of head and neck squamous cell carcinoma to cetuximab treatment depends on Aurora kinase A polymorphism 
Oncotarget  2014;5(14):5428-5438.
The aim of this study was to evaluate the efficiency of cetuximab-based anti-EGFR treatment and Aurora kinase A / B knockdown as a function of Aurora kinase polymorphism in HNSCC cell lines.
Materials and methods
First, protein expression of Aurora kinase A / B and EGFR and Aurora kinase A polymorphism were studied in tumour samples.
The survival and proliferation of Aurora kinase A homo- (Cal27) and heterozygous (HN) HNSCC cell lines was evaluated using a colony formation assay and a flow cytometric assay. Also, aneuploidy was determined. EGFR signalling pathway were visualised by western blotting.
Immunohistochemistry revealed the overexpression of Aurora kinase A / B in HNSCC. The knockdown of each kinase caused a significant decrease in clonogenic survival, independent of Aurora kinase A polymorphism. In contrast, cetuximab treatment impaired clonogenic survival only in the Aurora kinase A-homozygous cell line (Cal27).
This study provides in vitro evidence for the predictive value of Aurora kinase A polymorphism in the efficiency of cetuximab treatment. Resistance to cetuximab treatment can be overcome by simultaneous Aurora kinase A/B knockdown.
PMCID: PMC4170642  PMID: 24980817
Aurora kinase A polymorphism; Aurora kinase B; cetuximab; HNSCC
5.  Platelet-derived serotonin links vascular disease and tissue fibrosis 
Blocking 5-HT2B receptor provides a therapeutic target for fibrotic diseases caused by activated platelet release of serotonin during vascular damage.
Vascular damage and platelet activation are associated with tissue remodeling in diseases such as systemic sclerosis, but the molecular mechanisms underlying this association have not been identified. In this study, we show that serotonin (5-hydroxytryptamine [5-HT]) stored in platelets strongly induces extracellular matrix synthesis in interstitial fibroblasts via activation of 5-HT2B receptors (5-HT2B) in a transforming growth factor β (TGF-β)–dependent manner. Dermal fibrosis was reduced in 5-HT2B−/− mice using both inducible and genetic models of fibrosis. Pharmacologic inactivation of 5-HT2B also effectively prevented the onset of experimental fibrosis and ameliorated established fibrosis. Moreover, inhibition of platelet activation prevented fibrosis in different models of skin fibrosis. Consistently, mice deficient for TPH1, the rate-limiting enzyme for 5-HT production outside the central nervous system, showed reduced experimental skin fibrosis. These findings suggest that 5-HT/5-HT2B signaling links vascular damage and platelet activation to tissue remodeling and identify 5-HT2B as a novel therapeutic target to treat fibrotic diseases.
PMCID: PMC3092343  PMID: 21518801
6.  Inhibition of radiation induced migration of human head and neck squamous cell carcinoma cells by blocking of EGF receptor pathways 
BMC Cancer  2011;11:388.
Recently it has been shown that radiation induces migration of glioma cells and facilitates a further spread of tumor cells locally and systemically. The aim of this study was to evaluate whether radiotherapy induces migration in head and neck squamous cell carcinoma (HNSCC). A further aim was to investigate the effects of blocking the epidermal growth factor receptor (EGFR) and its downstream pathways (Raf/MEK/ERK, PI3K/Akt) on tumor cell migration in vitro.
Migration of tumor cells was assessed via a wound healing assay and proliferation by a MTT colorimeritric assay using 3 HNSCC cell lines (BHY, CAL-27, HN). The cells were treated with increasing doses of irradiation (2 Gy, 5 Gy, 8 Gy) in the presence or absence of EGF, EGFR-antagonist (AG1478) or inhibitors of the downstream pathways PI3K (LY294002), mTOR (rapamycin) and MEK1 (PD98059). Biochemical activation of EGFR and the downstream markers Akt and ERK were examined by Western blot analysis.
In absence of stimulation or inhibition, increasing doses of irradiation induced a dose-dependent enhancement of migrating cells (p < 0.05 for the 3 HNSCC cell lines) and a decrease of cell proliferation (p < 0.05 for the 3 HNSCC cell lines). The inhibition of EGFR or the downstream pathways reduced cell migration significantly (almost all p < 0.05 for the 3 HNSCC cell lines). Stimulation of HNSCC cells with EGF caused a significant increase in migration (p < 0.05 for the 3 HNSCC cell lines). After irradiation alone a pronounced activation of EGFR was observed by Western blot analysis.
Our results demonstrate that the EGFR is involved in radiation induced migration of HNSCC cells. Therefore EGFR or the downstream pathways might be a target for the treatment of HNSCC to improve the efficacy of radiotherapy.
PMCID: PMC3224383  PMID: 21896192
7.  A Controlled Challenge Study on Di(2-ethylhexyl) Phthalate (DEHP) in House Dust and the Immune Response in Human Nasal Mucosa of Allergic Subjects 
Environmental Health Perspectives  2008;116(11):1487-1493.
Few studies have yet addressed the effects of di(2-ethylhexyl) phthalate (DEHP) in house dust on human nasal mucosa.
We investigated the effects of house dust containing DEHP on nasal mucosa of healthy and house dust mite (HDM)–allergic subjects in a short-term exposure setting.
We challenged 16 healthy and 16 HDM-allergic subjects for 3 hr with house dust at a concentration of 300 μg/m3 containing either low (0.41 mg/g) or high (2.09 mg/g) levels of DEHP. Exposure to filtered air served as control. After exposure, we measured proteins and performed a DNA microarray analysis.
Nasal exposure to house dust with low or high DEHP had no effect on symptom scores. Healthy subjects had almost no response to inhaled dust, but HDM-allergic subjects showed varied responses: DEHPlow house dust increased eosinophil cationic protein, granulocyte-colony–stimulating factor (G-CSF), interleukin (IL)-5, and IL-6, whereas DEHPhigh house dust decreased G-CSF and IL-6. Furthermore, in healthy subjects, DEHP concentration resulted in 10 differentially expressed genes, whereas 16 genes were differentially expressed in HDM-allergic subjects, among them anti-Müllerian hormone, which was significantly up-regulated after exposure to DEHPhigh house dust compared with exposure to DEHPlow house dust, and fibroblast growth factor 9, IL-6, and transforming growth factor-β1, which were down-regulated.
Short-term exposure to house dust with high concentrations of DEHP has attenuating effects on human nasal immune response in HDM-allergic subjects, concerning both gene expression and cytokines.
PMCID: PMC2592268  PMID: 19057701
allergy; cytokines; DEHP; di(2-ethylhexyl) phthalate; house dust; hypersensitivity; microarray analysis; nasal challenge; nasal exposure system; nasal mucosa
8.  Differential Response of Mono Mac 6, BEAS-2B, and Jurkat Cells to Indoor Dust 
Environmental Health Perspectives  2007;115(9):1325-1332.
Airway toxicity of indoor dust is not sufficiently understood.
Our goal in this study was to describe the effects of indoor dust on human monocyte, epithelial, and lymphocyte cell lines. We aimed to a) obtain a comprehensive and intelligible outline of the transcriptional response; b) correlate differential transcription with cellular protein secretion; c) identify cell line–specific features; and d) search for indoor dust–specific responses.
Settled dust was sampled in 42 German households, and various contaminants were characterized. We exposed Mono Mac 6, BEAS-2B, and Jurkat cells to 500 μg/mL indoor dust for 6 hr. Outcome parameters included the transcriptional profile of an oligonucleotide microarray covering 1,232 genes. Significantly enriched Gene Ontology themes were calculated. Supernatant protein levels of 24 inflammatory response proteins served to confirm transcriptional results.
An intraclass correlation coefficient of 0.8 indicated reasonable microarray reproducibility. The transcriptional profile was characterized by enhancement of detoxification and a danger and defense response. Differential gene regulation correlated with protein secretion (Goodman and Kruskal’s gamma coefficient: 0.72; p < 0.01). Mono Mac 6 cells revealed the highest fraction of differentially expressed genes, dominated by up-regulation of various cytokines and chemokines. BEAS-2B cells revealed weaker changes in a limited set of inflammatory response proteins. No significant changes were observed in Jurkat cells.
Monocytes are particularly responsive to indoor dust. We observed a classical T-helper 1-dominated immune response, which suggested that bioorganic contaminants are relevant effectors in indoor dust.
PMCID: PMC1964888  PMID: 17805423
air pollution; analytical; cells; chemistry; cultured; expression profiling; gene; immunoassay; indoor dust; respiratory mucosa

Results 1-8 (8)