Biomedical subjects

Karl Götte

Publications and source records attributed to Karl Götte.

16 recordsLinked to original sources

PubMed2006

Hereditary hemorrhagic telangiectasia: an update on clinical manifestations and diagnostic measures.

Hereditary hemorrhagic telangiectasia (HHT), also known as Rendu-Osler-Weber disease, is an autosomal dominant disorder of the fibrovascular tissue. It is characterized by the classic triad of (muco-)cutaneous telangiectases, arteriovenous malformations with recurrent epistaxis and hemorrhages, and inheritance. A wide variety of clinical manifestations in HHT have been described. In more than 90% of the patients, nosebleeds are the first predominant symptom, therefore ENT physicians often play a key role as far as diagnosis and management of the disease are concerned. In spite of recent diagnostic and therapeutic progress, a cure for this often burdening and handicapping disease is still not available. Apart from affecting the nose, arteriovenous malformations (AVMs) may also affect the skin, lungs, brain, liver and gastrointestinal tract. The two known genes that are implicated in HHT are endoglin (ENG) located on chromosome 9q33-q34 and activin-receptor-like kinase (ALK1) located on chromosome 12q13. Mutations of ENG are observed in HHT type 1 with an incidence up to 40% for pulmonary AVMs, whereas mutations of ALK1 are observed in HHT type 2 with an incidence of only 14% for pulmonary AVMs, which clinically distinguishes these two types of mutation. The emphasis of this paper is mainly on the clinical manifestation, molecular genetics and diagnosis of HHT, taking account of current literature on HHT in order to better understand the complexity of the disease. Recent therapeutic options in the treatment of HHT have been omitted from this paper as they are subject of a following paper. HHT is more common than previously thought and shows a broad range of different clinical organ manifestations that can be sources of substantial morbidity and mortality, making HHT a continuing challenge for many sub-specialties where interdisciplinary diagnostic screening is mandatory in the management of the disease.

Activin Receptors, Type I↗

PubMed2005

Intratumoral genomic heterogeneity in advanced head and neck cancer detected by comparative genomic hybridization.

OBJECTIVES: Little is known about the extent of intratumoral genetic heterogeneity in head and neck squamous cell carcinoma (HNSCC). MATERIAL: Therefore, we examined 79 stage III and IV primary HNSCCs and matched lymph node metastases for over- and underrepresentation of specific chromosome regions by comparative genomic hybridization. RESULTS: The overall ratio of gains and losses was higher in metastases (M) than in primary (P) tumors (4/1 vs. 2.5/1). Gains of 3q (78.1% P vs. 87.5% M) and 11q (78.1% P vs. 62.5% M), and deletions of 3p (43.8% P vs. 34.4% M) and 9p (31.3% P vs. 15.6% M) were most frequently detected. The highest rate of intratumoral discordance was observed for primary tumors and corresponding metastases (32.8%) compared to matched pairs of 2 metastases (26.5%), and of 2 anatomically distinct sides of 1 primary tumor (24.3%). Furthermore, the discordance rate was dependent on the primary tumor site (oral cavity 49.2%, oropharynx 31%, hypopharynx 30.3% and larynx 27.3%). In some tumors, the extent of genomic discordance argues against a monoclonal origin. CONCLUSION: We demonstrate a high individual variation of intratumoral genomic heterogeneity depending on the localization and selection of matched pairs. These findings are of specific importance in view of establishing prognostic markers.

Aged↗

PubMed2005

Antiangiogenic therapy of head and neck squamous cell carcinoma by vascular endothelial growth factor antisense therapy.

Angiogenesis is increased in various human cancers, including head and neck squamous cell carcinoma (HNSCC), and correlates with tumor progression and metastasis. Vascular endothelial growth factor (VEGF) has been shown to be a key regulator of angiogenesis. We determined whether VEGF antisense oligonucleotide treatment can decrease the angiogenic activity of HNSCC cell lines in vitro and of HNSCC xenografts in vivo. Established human HNSCC cell lines were screened for VEGF expression at both mRNA and protein levels. By using a 21-mer antisense phosphorothioate oligonucleotide targeting the translation start site of human VEGF mRNA, we examined the modulation of VEGF expression in cell line supernatants by capture ELISA and in cell lysates by Western blotting. Human endothelial cells were grown in conditioned medium produced from the treated tumor cells. Endothelial cell proliferation was determined by cell count, and endothelial cell migration was measured using a modified Boyden chamber. Mice with HNSCC xenografts were treated with PBS, VEGF antisense or sense oligonucleotides (10 mg/kg i.p. injection, 3 times/week), respectively, and tumor volumes were measured for 5 weeks. VEGF antisense oligonucleotide treatment resulted in a significant reduction of VEGF protein expression compared to treatment with the sense control. Although the growth rate of the tumor cell lines was not affected, the addition of conditioned medium from VEGF antisense-treated tumor cells resulted in decreased endothelial cell proliferation and migration. VEGF antisense oligonucleotide treatment of HNSCC xenografts resulted in a significant tumor growth suppression. These results suggest that downmodulation of VEGF using antisense oligonucleotides may be a potential therapy for the inhibition of angiogenesis in HNSCC.

Angiogenesis Inhibitors↗

PubMed2005

Altered expression of cell cycle regulators p21, p27, and p53 in tumors of salivary glands and paranasal sinuses.

CIP/KIP family proteins entitled p21(WAF1/CIP1) and p27(KIP1) have key positions in cell cycle regulation leading to an arrest of cell proliferation. They are supposed to enable a repair process of DNA damage. In several human tumors, a loss of these proteins is associated with poor clinical outcome. The role of these cell cycle regulators in tumors of salivary gland and paranasal sinus origin is still unclear. In this study it was intended to demonstrate and compare the expression of p21, p27, and p53 in benign and malignant tumors of salivary glands and paranasal sinuses. Protein expression was detected by conventional immunohistochemistry (IHC). Additionally, we performed tyramide signal amplified immunohistochemistry (TSA-IHC) for p21 and p53 levels. Nine adenoid cystic carcinomas, 5 adenocarcinomas, 4 cylindrical cell carcinomas, as well as 30 pleomorphic adenomas and 26 inverted papillomas, were studied. In 78% of all adenoid cystic carcinomas a complete loss of p27 expression could be identified, whereas 60% of the adenocarcinomas overexpressed the protein. The majority of cylindrical cell carcinomas showed distinct cytoplasmic accumulation of p27. All malignant tumors turned out to be positive for p21 after performing TSA-IHC, although 72% of those samples had shown weak to negative protein levels in conventional immunostaining. Immunohistochemical results of CIP/KIP proteins were compared to p53 expression as well as to main clinical parameters. The study sheds new light upon the role of CIP/KIP protein family in tumors of salivary glands and paranasal sinuses. Furthermore, it is the first description of p21 and p53 TSA-IHC in these tumor types.

Adenocarcinoma↗

PubMed2005

Dual FISH analysis of benign and malignant tumors of the salivary glands and paranasal sinuses.

To date, the underlying genomic changes in benign and malignant tumors of salivary-gland and paranasal-sinus origin are poorly understood. This is due in part to the low incidence of these tumors and the enormous histological variety of tumors within this head and neck region. We examined 58 of these tumors (14 adenoid cystic carcinomas, 9 adenocarcinomas, 5 cylindrical carcinomas, 11 pleomorphic adenomas, and 19 inverted papillomas) by dual fluorescence in situ hybridization (FISH) with centromere-specific probes on six chromosomes (3, 7, 9, 11, 17, and 18) for numerical changes. In adenoid cystic carcinomas, monosomy of chromosome 17 and polysomy of chromosomes 3, 9 and 11 were most frequently encountered. In adenocarcinomas, monosomy of chromosome 17 and polysomy of chromosomes 7 and 11 were most frequent. In cylindrical cell carcinomas, polysomy of chromosomes 7, 9, 11 and 17 was present in the majority of tumors. Disomy is rare, even in benign tumors. Polysomy is more frequent in malignant tumors than in benign. Tetrasomy is found almost only in malignant tumors. In summary, the occurrence of polysomy might reflect a step towards malignancy in tumors of the salivary glands and paranasal mucosa. Polysomy of chromosome 11 could be defined as typical for all investigated histological types of malignant tumor in this region of the head and neck.

Adenocarcinoma↗

PubMed2004

Sinonasal malignancy: what's new?

Tumors of the nasal cavity are located at a complex anatomic site and show a huge histological diversity. Although dealing with a rare malignancy, the last decade has brought--besides new histological and clinical classifications--a variety of new insights into etiological agents, tumor biology and therapeutic concepts as well as valuable overviews of rare histological subtypes. This review tries to disentangle the different medical and scientific aspects of the most frequently encountered histological types of tumors in the nasal cavity and the paranasal sinuses. We concentrate on epidemiology, classification, etiology, cytogenetics and molecular genetics, outcome and prognosis as well as treatment modalities, as far as the past few years have brought considerable new insights. Our principal aim is to provide the clinician with important data from publications of the last decade.

Humans↗

PubMed2004

Intratumoral genomic heterogeneity in primary head and neck cancer and corresponding metastases detected by dual-FISH.

Intratumoral genomic heterogeneity, which can be defined as both intersample and intrasample heterogeneity, is still a poorly understood phenomenon in head and neck squamous cell carcinoma (HNSCC) with presumed implications on tumor behavior and even prognosis. We analyzed 89 tumor specimen from 37 HNSCC patients by fluorescence in situ hybridization (dual-FISH) using specific DNA probes binding to centromeric sites of 6 chromosomes to investigate intratumoral heterogeneity. A derivation from disomy in at least 1/6 chromosomes was detected in 88/89 (99%) specimen. In 33% of these samples, a change in ploidy could be suspected. Intrasample heterogeneity was detected in 68/89 (76%). Intrasample heterogeneity was more pronounced in primary tumors than in metastatic tumors. Analysis of the intersample heterogeneity revealed notable differences between the 6 chromosomes with the highest discordance detected for chromosome 3 (46%) and the lowest for chromosome 11 (27%). Following our results, it seems important to us to underline that intratumoral heterogeneity exists as intra- and sample heterogeneity in HNSCC. Altogether, trisomic cells were significantly more frequent in primary tumors than in metastases (p=0.01) while, in turn, monosomic cells were significantly more frequent in metastases (p=0.029). In individual cases the extent of discordance between corresponding samples made a common clonal precursor unlikely. In these cases, the synchronous development of a primary tumor and a carcinoma of unknown primary ('CUP syndrome'), otherwise undetected, should be considered.

Aged↗

PubMed2004

Expression of IL-18 in patients with head and neck squamous cell carcinoma.

Interleukin-18 (IL-18), a recently described cytokine secreted mainly by macrophages, stimulates interferon-gamma (IFN-gamma) production by natural killer cells and T cells. The purpose of this study was to determine tissue expression and serum levels of IL-18 in head and neck squamous cell carcinoma (HNSCC) and to evaluate ethanol and endotoxin-driven cytokine secretion. In 24 patients with primary HNSCC and 28 healthy controls, PBMC were isolated and incubated with 50 mM ethanol, LPS (doses 25 ng/ml, 250 ng/ml, 2500 ng/ml) and both agents for 24 h. Levels of IL-18 in serum, and cell supernatants were analysed by capture ELISA, IL-18 tissue level by immunoblotting. Serum levels of IL-8, IL-10 and IL-12, IFN-gamma, and endotoxin plasma levels were also determined. Statistical analysis involved Welch t-test and Page's test for trend. The majority of patients with HNSCC had high concentrations of serum IL-18. The level of IL-18 in the sera of these patients had a mean level of 271.7 pg/ml, while the mean IL-18 serum level in healthy controls was 174,0 pg/ml (p<0.001). Levels of IL-10 and IL-12, IFN-gamma were not increased in patients. Endotoxin was not detectable in either group. LPS stimulated dose-dependently IL-18 secretion from PBMC of patients and controls in vitro (p<0.05). Incubation with ethanol alone did not affect basal IL-18 secretion, but ethanol reduced LPS-stimulated IL-18 secretion compared to LPS stimulation alone. The mRNA expression of IL-18 in unstimulated PBMC and the response of PBMC to ethanol and LPS was similar in patients and controls. Our data on elevated serum levels of IL-18 in the majority of HNSCC cancer patients, irrespective of its biological activity, suggest that serum IL-18 might be a candidate for a new marker for HNSCC. The pathways for IL-18 production and its mechanisms of action in patients with HNSCC remain to be determined. Understanding of the immunological pathways might offer new therapeutic options in head and neck cancer in the future.

Carcinoma, Squamous Cell↗

PubMed2004

p53 codon 72 polymorphic variants, loss of allele-specific transcription, and human papilloma virus 16 and/or 18 E6 messenger RNA expression in squamous cell carcinomas of the head and neck.

A polymorphism at codon 72 of the human tumor suppressor p53 determines translation into either arginine or proline. Yet, the impact of this amino acid variability on the risk to develop malignant tumors, particularly carcinomas associated with human papilloma virus (HPV) infections, remains unresolved because of contradictory results. To address a potential correlation between the different genotypes and the manifestation of squamous cell carcinomas of the head and neck (SCCHN), we determined the p53 codon 72 in 193 healthy subjects and 122 unselected SCCHN with known HPV status. Furthermore, loss of allele-specific transcription was analyzed in p53 codon 72 heterozygous (Arg/Pro) SCCHN and correlated with HPV 16 and/or 18 E6 transcript expression. We found a moderately increased risk (odds ratio, 1.86; 95% confidence interval, 1.0-3.3) for individuals with germ line heterozygosity to develop SCC of the pharynx. On the other hand, p53 codon 72 polymorphic variants, most notably the Arg/Arg genotype, showed no association with the presence of HPV 16 and/or 18 E6 transcript. Moreover, there was no evidence for HPV-driven selection in SCCHN with allele-specific loss of transcription. Our data suggest that the p53 codon 72 polymorphism has a minor impact on the development of SCCHN.

Adult↗

PubMed2003

Intratumoral genomic heterogeneity in advanced head and neck cancer detected by comparative genomic hybridization.

Little is known about the extent of intratumoral genetic heterogeneity in head and neck squamous cell carcinoma (HNSCC). We therefore examined 79 stage III and IV primary HNSCCs (P) and matched lymph node metastases (M) for over- and underrepresentation of specific chromosome regions by comparative genomic hybridization (CGH). The overall ratio of gains and losses was higher in metastases than in primary tumors (4/1 vs. 2.5/1). Gains of 3q (78.1% P vs. 87.5% M) and 11q (78.1% P vs. 62.5% M) and deletions of 3p (43.8% P vs. 34.4% M) and 9p (31.3% P vs. 15.6% M) were most frequently detected. The highest rate of intratumoral discordance was observed for primary tumors and corresponding metastases (32.8%) compared with matched pairs of two metastases (26.5%) and of two anatomically distinct sides of one primary tumor (24.3%). Furthermore, the discordance rate was dependent on the primary tumor site (oral cavity 49.2%, oropharynx 31%, hypopharynx 30.3%, and larynx 27.3%). In some tumors, the extent of genomic discordance argues against a monoclonal origin. In conclusion, we found a high individual variation of intratumoral genomic heterogeneity depending on the localization and selection of matched pairs. These findings are of specific importance in view of establishing prognostic markers.

Aged↗

PubMed2003

Is the p53 inactivation frequency in squamous cell carcinomas of the head and neck underestimated? Analysis of p53 exons 2-11 and human papillomavirus 16/18 E6 transcripts in 123 unselected tumor specimens.

Mutations and interaction with high-risk human papillomavirus (HPV) E6 oncoprotein are well-established mechanisms of p53 inactivation. In a series of 123 unselected squamous cell carcinomas of the head and neck (SCCHN), we performed sequence analysis of the entire coding region of p53 transcript and determined the presence of the E6 transcripts of HPV 16 and 18. Aberrant p53 transcripts were identified in 97 (79%) SCCHN. HPV 16 and/or 18 E6 transcripts were detected in 37 (30%) tumor specimens, including 20 (77%) of the 26 p53 wild-type tumors. The likely inactivation of p53 in 117 (95%) of the 123 SCCHN suggests that this event could be obligatory in the multistep process of carcinogenesis.

Carcinoma, Squamous Cell↗

PubMed2003

Abrogation of VEGF expression in human head and neck squamous cell carcinoma decreases angiogenic activity in vitro and in vivo.

Angiogenesis is increased in various human cancers, including head and neck squamous cell carcinoma (HNSCC), and correlates with tumor progression and metastasis. Vascular endothelial growth factor (VEGF) has been shown to be a key regulator of angiogenesis. We determined whether VEGF antisense oligonucleotide treatment can decrease angiogenic activity of HNSCC cell lines in vitro and of HNSCC xenografts in vivo. Established human HNSCC cell lines were screened for VEGF expression at both mRNA and protein levels. By using a 21-mer antisense phosphorothioate oligonucleotide targeting the translation start site of human VEGF mRNA, we examined modulation of VEGF expression in cell line supernatants by capture ELISA, and in cell lysates by Western blotting. Human umbilica vein endothelial cells (HUVEC) were grown in conditioned medium produced from the treated tumor cells. Endothelial cell (EC) proliferation was determined by cell count and EC migration was measured using a modified Boyden chamber. Mice with HNSCC xenografts were treated with PBS, VEGF antisense or sense oligonucleotides (10 mg/kg; i.p. injection), respectively and tumor volumes were measured for 5 weeks. VEGF antisense oligonucleotide treatment resulted in a significant reduction of VEGF protein expression compared to sense control. Although the growth rate of the tumor cell lines was not affected, addition of conditioned medium from VEGF antisense-treated tumor cells resulted in decrease of endothelial cell proliferation and migration. VEGF antisense oligonucleotide treatment of HNSCC xenografts resulted in a significant tumor growth suppression. These results suggest that downmodulation of VEGF using antisense oligonucleotides may be a potential therapy for the inhibition of angiogenesis in HNSCC.

Angiogenesis Inhibitors↗

PubMed2002

Tumor-associated antigens as possible targets for immune therapy in head and neck cancer: comparative mRNA expression analysis of RAGE and GAGE genes.

Specific immune therapy targeting residual areas of cancer cells may emerge as a powerful treatment strategy for head and neck squamous cell carcinoma (HNSCC). In order to define possible targets for immune therapy, we evaluated the frequency of two groups of tumor antigens-the RAGE and GAGE families-by means of reverse transcriptase polymerase chain reaction using primary HNSCCs (n = 28), mucosa specimens as normal controls (n = 10) and HNSCC cell lines (n = 6). By means of specific primer selection we could differentiate between RAGE-1, -2, -3 and -4, as well as between two groups of GAGE genes (GAGE-1,2,7 vs GAGE-3,4,5,6,8). While all mucosa tissues (from smokers and non-smokers) were negative for both antigen families, 24/28 investigated tumors were positive for up to 5 tumor antigens. Among the RAGE genes, RAGE-1-positive tumors were the most abundant (8/28), followed by RAGE-2 (7/28) and RAGE-4 (6/28). Differences in the locations of HNSCCs were reflected by different RAGE family members being expressed most frequently: larynx, RAGE-1; oropharynx, RAGE-2; and hypopharynx, RAGE-4. Primers against GAGE-1,2,7 and GAGE-3,4,5,6,8 revealed 6/27 and 16/27 positive tumors, respectively. This report suggests that RAGE genes and GAGE-3,4,5,6,8 may be promising candidates for specific immune therapy in HNSCC.

Antigens, Neoplasm↗

PubMed2002

EGFR antisense treatment of human HNSCC cell lines down-regulates VEGF expression and endothelial cell migration.

Overexpression of the epidermal growth factor receptor (EGFR) is thought to play a key role in the development of head and neck squamous cell carcinoma (HNSCC) primarily through its effect on promoting uncontrolled cell proliferation. Blocking EGFR ligand binding might also inhibit angiogenesis and down-regulate the production of angiogenic factors. Angiogenesis is increased in various human tumors, including head and neck squamous cell carcinoma (HNSCC), and correlates with tumor progression and metastasis. The vascular endothelial growth factor (VEGF) is thought to be the most important angiogenic factor. We determined whether VEGF antisense oligonucleotide treatment can decrease angiogenic activity of HNSCC cell lines in vitro. By using a 21-mer antisense phosphorothioate oligonucleotide targeting the translation start site of human EGFR mRNA, we examined modulation of VEGF expression in cell line supernatants by capture ELISA, and in cell lysates by Western blotting. Human umbilica vein endothelial cells (HUVEC) were grown in conditioned medium produced from the treated tumor cells. Endothelial cell migration was measured using a modified Boyden chamber. EGFR antisense oligonucleotide treatment resulted in a significant reduction of VEGF protein expression compared to sense oligonucleotide control. Addition of conditioned medium from EGFR antisense-treated tumor cells resulted in decreased endothelial cell migration. In conclusion, therapeutic strategies targeting EGFR signaling in head and neck cancer might have an antitumor effect mediated in part by inhibition of tumor angiogenesis.

Carcinoma, Squamous Cell↗

PubMedDate not supplied

Targeting chemotherapy-induced VEGF up-regulation by VEGF antisense oligonucleotides in HNSCC cell lines.

BACKGROUND: Angiogenesis is increased in various human cancers, including head and neck squamous cell carcinoma (HNSCC), and correlates with tumour progression and metastasis. Vascular endothelial growth factor (VEGF) has been shown to be a key regulator of angiogenesis. Tumour treatment with anticancer agents might have an effect on the secretion of VEGF. Therefore, we determined whether certain chemotherapeutic agents stimulate VEGF secretion in HNSCC and whether VEGF antisense oligonucleotide treatment can modulate these effects in vitro. MATERIALS AND METHODS: The effect of chemotherapeutic agents (Cisplatin, Carboplatin and 5-FU) on the production of VEGF was investigated on established human HNSCC cell lines at both mRNA and protein levels. By using a 21-mer VEGF antisense phosphorothioate oligonucleotide targeting the translation start site of human VEGF mRNA, we examined modulation of VEGF expression in cell line supernatants by capture ELISA. RESULTS: The treatment of HNSCC cell lines with chemotherapeutic agents resulted in a significant induction of VEGF production. Carboplatin most prominently induced the release of VEGF from the tumour cells. VEGF antisense oligonucleotide treatment resulted in a significant reduction of chemotherapy-induced VEGF up-regulation compared to sense control. CONCLUSION: Induction of VEGF secretion might contribute to the frequently observed drug resistance of HNSCC to chemotherapeutic agents. This molecular effect might be reduced by the use of VEGF antisense oligonucleotides in head and neck cancer therapy.

Antineoplastic Agents↗

PubMedDate not supplied

Serum levels of interleukin-6 in patients with primary head and neck squamous cell carcinoma.

Interleukin (IL)-6 plays a central role as a differentiation and growth factor of tumor cells. IL-6 has been identified in a wide variety of malignancies, including head and neck squamous cell carcinomas (HNSCC). The aim of this study was to investigate the association between the serum levels of IL-6 in HNSCC patients and the biological characteristics of the tumor as well as the clinicopathological status of the patients. The circulating level of IL-6 in sera from patients with various HNSCC (n = 90) as well as from healthy normal controls (n = 39) was investigated. Serum IL-6 concentrations were determined as serum immunoreactivity using a quantitative sandwich enzyme immunoassay technique. For statistical analysis, the Kruskal-Wallis test was performed. The majority of the patients with HNSCC were found to have high serum IL-6 concentrations. The IL-6 levels in the sera of patients with cancer ranged from below the detection limit to 312.8 pg/ml (mean, 19.5 pg/ml). In contrast, the IL-6 serum levels in 39 healthy individuals ranged from below the detection limit to 52.2 pg/ml (mean, 6.0 pg/ml), with the concentration being significantly higher in HNSCC patients (p < 0.001). Furthermore, the correlation of the IL-6 serum concentration with tumor stage was significant (p = 0.04). Accordingly, there was a significant difference of IL-6 serum concentration of tumors with positive and negative lymph nodes (p = 0.045), with concentration being significantly higher in lymph node-positive tumors. Our data on elevated IL-6 serum levels in the majority of HNSCC cancer patients and its correlation with tumor stage and lymph node status suggest that serum IL-6 reflects the proliferative activity of the tumor in patients with head and neck cancer. IL-6 serum determinations might serve as a biological marker and help to identify advanced head and neck tumors.

Adult↗