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Biomedical subjects

Peter Bugert

Publications and source records attributed to Peter Bugert.

At least 19 recordsLinked to original sources
PubMed2006

Aurora kinases A and B and familial breast cancer risk.

Aurora genes play a crucial role in tumourigenesis and are overexpressed in many kinds of cancers. We investigated whether coding variants within the Aurora genes are associated with familial breast cancer risk. While AURKA Phe31Ile (1712T>A) and AURKB Thr298Met (893G>A) showed no association, the synonymous AURKB Ser295Ser (885A>G) polymorphism resulted in an increased breast cancer risk for carriers of the homozygous 885G genotype (OR=1.45, 95% CI=1.05-2.0, P=0.02). Due to the impact of aurora kinases in the loss of chromosomal integrity during carcinogenesis, this variant may also influence the therapy outcome in breast cancer.

Aurora Kinase A↗
PubMed2006

Association of the ARLTS1 Cys148Arg variant with familial breast cancer risk.

Recently, ARLTS1 (ADP-ribosylation factor-like tumor suppressor gene 1) has been identified as a tumor suppressor gene, playing a major role in apoptotic signaling. The ARLTS1 Trp149Stop mutation has been shown to predispose to general familial cancer and high-risk familial breast cancer (BC), provoking the attenuation of apoptotic function. We studied the impact of the ARLTS1 Pro131Leu and Cys148Arg variants on high-risk familial and familial BC risk, investigating 482 familial BC cases (including 305 high-risk cases) and 530 control individuals. Unlike ARLTS1 Pro131Leu, Cys148Arg revealed a significant association with an increased risk of high-risk familial BC (odds ratio (OR)=1.47, 95% confidence interval (95% CI)=1.04-2.06, p=0.03) in a dose-dependent manner (ptrend=0.007). The genotype distribution of Cys148Arg in familial cases was similar, indicating significance as well (OR=1.48, 95% CI=1.10-1.99, p=0.009; ptrend=0.003). On the basis of the small number of 46 cases, we additionally showed an association between the Trp149Stop mutation and an increased risk of bilateral BC (OR=4.11, 95% CI=1.27-13.31, p=0.011).

ADP-Ribosylation Factors↗
PubMed2006

Polymorphisms in genes involved in GH1 release and their association with breast cancer risk.

The regulation of growth hormone 1 (GH1) and insulin-like-growth factor-1 (IGF-1) release is under the influence of three pituitary hormones [growth hormone releasing hormone (GHRH), ghrelin (GHRL) and somatostatin (SST)], which act in an autocrine/paracrine fashion in the breast. By binding to their respective receptors, they control cell proliferation, differentiation and apoptosis in a GH1/IGF-1-dependent manner. We investigated single nucleotide polymorphisms (SNPs) in the GHRH, GHRHR, GHRL, GHSR, SST and SSTR2 gene regions in a Polish and a German cohort of 798 breast cancer cases and 1011 controls. Our study revealed an association of a novel TC repeat polymorphism in the SST promoter with a decreased breast cancer risk in the Polish study population [odds ratio (OR), 0.65; 95% confidence interval (CI), 0.44-0.96]. The closely linked SNP IVS1 A+46G showed the same trend. For both polymorphisms the association was stronger in women above the age of 50 (OR, 0.33; 95% CI, 0.14-0.76 and OR, 0.39; 95% CI, 0.18-0.87, respectively). The protective effect of these polymorphisms was confirmed in a haplotype analysis among women above 50 years of age and carrying the two variant alleles (OR, 0.37; 95% CI, 0.17-0.80). In the independent German population, we observed slightly decreased ORs among women above the age of 50 years. In the SSTR2 gene, carriers of the promoter 21/21 TG repeat genotype were at a decreased breast cancer risk (OR, 0.62; 95% CI, 0.41-0.94) compared to carriers of the other genotypes in the Polish population. Furthermore, we identified a protective effect of the GHRHR C-261T SNP in both populations (joint analysis CT+TT versus CC: OR, 0.80; 95% CI, 0.65-0.99). This effect was carried by a haplotype containing the protective allele. Thus, our study concludes a possible protective influence of distinct polymorphisms in genes involved in GH1 release on breast cancer risk.

Adolescent↗
PubMed2006

Characterization of the neuronal dopamine transporter DAT in human blood platelets.

Compelling evidence suggests a monoaminergic dysfunction in the aetiology of various neuro-psychiatric diseases such as depression, attention deficit hyperactivity disorder (ADHD), schizophrenia, addiction and Parkinson's disease. The efficiency of monoaminergic neurotransmission is controlled by rapid and efficient reuptake of dopamine out of the synaptic cleft by specific transporters for dopamine, serotonin and noradrenaline. In case of the serotonin transporter, many investigators have determined its function and expression also on peripheral cells such as blood platelets under the assumption that changes in protein expression in these cells might reflect neuronal changes. No comparable studies have so far been performed with respect to the dopamine transporter due to the lack of information about the existence of this protein in platelets. Here, we present pharmacological, immunological as well as microarray and PCR data that human blood platelets express the dopamine transporter protein (DAT), which is identical to that first identified in neurons. Because DAT expression is modulated also in non-neuronal cells independently of gene transcription, platelets may well serve as an easy accessible peripheral system to study DAT regulation in mental diseases or during drug treatment or drug abuse.

Blood Platelets↗
PubMed2006

The single nucleotide polymorphism IVS1+309 in mouse double minute 2 does not affect risk of familial breast cancer.

The mouse double minute 2 (MDM2) oncoprotein promotes cell survival and cell cycle progression by inhibiting the p53 tumor suppressor protein. Further, MDM2 overexpression can inhibit DNA double-strand break repair in a p53-independent manner. Recently, it was shown that a single nucleotide polymorphism (SNP) in the MDM2 promoter was associated with an accelerated tumor formation in individuals with a p53 mutation. The present case-control study investigated the association of this SNP (IVS1+309) with the risk and the age of onset of familial breast cancer in patients with unknown p53 mutation status. Data from 549 women affected by familial breast cancer and 1,065 healthy controls were analyzed. The cases did not carry BRCA1/2 mutations. Cases and controls showed a similar genotype distribution and the SNP did not seem to modify the age of onset of familial breast cancer. The data were also examined taking into account the presence of any additional cancer after breast cancer and the family history of cases; however, no association was found. These results suggest that the SNP IVS1+309 alone affects neither the risk nor the age of onset of heritable breast cancer.

Adult↗
PubMed2006

In vitro analysis of differential expression of collagens, integrins, and growth factors in cultured human chondrocytes.

OBJECTIVES: Tissue engineering represents a promising method for the construction of autologous chondrogenic grafts for reconstructive surgery. In cultured chondrocytes, the dedifferentiation and proliferation of the cells are critical factors that influence the generation of transplants. The aim of our study was to find and characterize markers for cell proliferation and dedifferentiation in cultured chondrocytes. STUDY DESIGN AND SETTING: Human chondrocytes were isolated from septal cartilage and held in primary cell culture. Cells were harvested after 1, 6, and 21 days. The differentiation of the cells was investigated with bright-field microscopy, the expression patterns of various proteins using immunohistochemistry, and the expression of distinct genes with the microarray technique. RESULTS: The chondrocytes showed a strong proliferation. After 6 and 21 days, collagen 9 and 10 were downregulated; collagen 11 was activated. Collagen 1 and 2 were downregulated after 6 days but were reactivated after 21 days. Tumor growth factor beta (TGF-beta)1 was strongly expressed on days 1, 6, and 21, TGF-beta2 was never expressed, and TGF-beta3 and -beta4 were upregulated from day 1 to day 21. The TGF-beta receptor III was expressed on days 1, 6, and 21. Integrin beta1, beta5, and alpha5 were upregulated from day 1 to day 21; integrin beta3 was downregulated. CONCLUSION AND SIGNIFICANCE: Collagens 3, 4, 8, 9, and 11 might be new markers for the dedifferentiation of chondrocytes. Collagen 2 might be a marker for the synthetic activity of the cells rather than the dedifferentiation. TGF-beta3 and -beta4 might influence the dedifferentiation, which is fortified by the expression of TGF-beta receptor III. Integrin beta1, beta5, and alpha5 might be involved in signal transmission for the dedifferentiation.

Biomarkers↗
PubMed2006

In vitro analysis of integrin expression during chondrogenic differentiation of mesenchymal stem cells and chondrocytes upon dedifferentiation in cell culture.

Tissue engineering represents a promising method for generating chondrogenic grafts for reconstructive surgery. In cultured chondrocytes, the dedifferentiation of cells seems unavoidable for multiplication. Stem cells, however, displaying unlimited self-renewal and the capacity to differentiate towards chondrocytes, might be usable after further characterization. As the interactions between the extracellular matrix and the cellular compartment can alter the cellular behaviour, we investigated the expression of integrins using microarray analysis during chondrogenic differentiation of human mesenchymal stem cells (MSC) in comparison with de-differentiating human chondrocytes (HC) harvested during septoplasty. During chondrogenic differentiation of MSC, the fibronectin-receptor (Integrin beta1alpha5), fibronectin and the GPIIb/IIIa-receptor were downregulated. The components of the vitronectin-receptor (Integrin alphavbeta3) and CD47 were constantly expressed and ILK was downregulated. Vitronectin and osteopontin were not expressed by the cells. In HC, Integrin beta1alpha5 in conjunction with the ligand fibronectin were upregulated during dedifferentiation, Integrin alphavbeta3 as well as the GBIIb/IIIa-receptor were activated on day 21 but neither vitronectin nor osteopontin were expressed by the cells. The integrins, beta2, beta4, beta6, beta8 and alpha2, alpha4, alpha6, alpha7, alpha11, were not expressed at any time. ILK, CD47, and ICAP were activated with ongoing dedifferentiation. In conclusion, a candidate for signal-transmission is the fibronectin receptor (integrin alpha5beta1) in conjunction with its ligand fibronectin. Other receptors, e.g. for vitronectin and osteopontin (alphavbeta3), or their ligands do not seem to be involved in signal transmission for dedifferentiation. The GPIIb/IIIa-receptor might assist the process of dedifferentiation. Intracellularly, ILK, ICAP1 and CD47 might be involved in the transduction of integrin-dependent signals.

Cell Differentiation↗
PubMed2005

c-MYC Asn11Ser is associated with increased risk for familial breast cancer.

c-MYC is a multifaceted protein that regulates cell proliferation, differentiation and apoptosis. Its crucial role in diverse cancers has been demonstrated in several studies. Here, we analysed the influence of the rare c-MYC Asn11Ser polymorphism on familial breast cancer risk by performing a case-control study with a Polish (cases n = 349; controls n = 441) and a German (cases n = 356; controls n = 655) study population. All cases have been tested negative for mutations in the BRCA1 and BRCA2 genes. A joint analysis of the Polish and the German study population revealed a 54% increased risk for breast cancer associated with the heterozygous Asn11Ser variant (OR = 1.54, 95% CI 1.05-2.26, p = 0.028). The breast cancer risk associated with this genotype increases above the age of 50 years (OR = 2.24, 95% CI 1.20-4.21, p = 0.012). The wild-type amino acid Asn of this polymorphism is located in the N-terminal MYC transactivation domain and is highly conserved not only among most diverse species but also in the N-MYC homologue. Due to the pivotal role of c-MYC in diverse tumours, this variant might affect the genetic susceptibility of other cancers as well.

Amino Acid Sequence↗
PubMed2005

Association of the CASP10 V410I variant with reduced familial breast cancer risk and interaction with the CASP8 D302H variant.

Dysregulation of apoptosis plays a crucial role in carcinogenesis. As part of death receptor- and mitochondrion-mediated apoptosis, the homologues caspases 10 and 8 may act as low-penetrance breast cancer (BC) susceptibility genes. In death receptor-mediated apoptosis, engagement of death receptors by their ligands involves the assembly of the death-inducing signalling complex (DISC). In mitochondrion-mediated apoptosis, the release of cytochrome c into the cytosol results in apoptosome formation. Recruitment of both caspases 10 and 8 (CASP10 and CASP8, respectively) to DISC and apoptosome leads to their activation by dimerization. We investigated the influence of the coding CASP10 variant V410I (G1228A) by performing a case-control study - using 511 familial BC cases and 547 control subjects - on BC risk and revealed a significant association of V410I with a reduced risk (OR = 0.62, 95% CI = 0.43-0.88, P = 0.0076) related to the number of variant alleles (P(trend) = 0.0039). As CASP10 and CASP8 functionally co-operate during apoptosis, we analysed the mutual effect of both CASP10 V410I and CASP8 D302H, resulting in a significant association between the number of the variant alleles I410 and H302 and a highly decreased familial BC risk (OR = 0.35, P(trend) = 0.007), pointing to the interaction between the CASP10 and CASP8 polymorphisms in breast carcinogenesis.

Adult↗
PubMed2005

Association of death receptor 4 haplotype 626C-683C with an increased breast cancer risk.

Dysregulation of apoptosis plays a crucial role in carcinogenesis. Tumour necrosis factor-related apoptosis-inducing ligand stimulates the extrinsic apoptotic pathway by binding to death receptor 4 (DR4). Thus, genetic alterations within the candidate tumour suppressor gene DR4 would be expected to provoke a deficient apoptotic signalling thereby facilitating the development of cancer. The DR4 variants Thr209Arg and Glu228Ala were genotyped in a series of 521 breast cancer cases and 1100 control subjects from Germany, determining their impact on breast cancer risk. Neither Thr209Arg (626C>G) nor Glu228Ala (683A>C) alone were significantly associated with breast cancer risk [odds ratio (OR) = 0.84, 95% confidence interval (CI) = 0.65-1.08, P = 0.18 and OR = 0.89, 95% CI = 0.72-1.12, P = 0.30]. However, haplotype analysis revealed a 3.5-fold risk for carriers of the 626C-683C haplotype (OR = 3.52, 95% CI = 1.45-8.52, P = 0.003).

Adult↗
PubMed2005

TP53-binding protein variants and breast cancer risk: a case-control study.

INTRODUCTION: The TP53-binding protein (53BP1) has been shown to influence TP53-mediated transcriptional activation, thus playing a pivotal role in DNA damage signalling. Genetic aberrations in TP53 and in ATM and CHEK2 predispose to cancer. We have therefore examined the effects of 53BP1 single nucleotide polymorphisms (D353E, G412S, and K1136Q) and the novel 53BP1 6bp deletion (1347_1352delTATCCC) on breast cancer risk. METHODS: Allelic discrimination was performed to investigate the frequencies of 53BP1 D353E, G412S, and K1136Q and of 1347_1352delTATCCC in 353 patients with breast cancer and 960 control individuals. RESULTS: No significant association of 53BP1 D353E, G412S, or K1136Q with breast cancer risk was detected. 53BP1 1347_1352delTATCCC, leading to the loss of an isoleucine and a proline residue, showed a nonsignificant inverse association with breast cancer risk (odds ratio = 0.61, 95% confidence interval = 0.22 to 1.68, P = 0.34). CONCLUSION: The lack of association casts doubt on the putative effects of D353E, G412S, and K1136Q on breast cancer risk. Investigating a larger study cohort might elucidate the influence of the 6bp deletion 1347_1352delTATCCC. Studying the functional effect and the impact of this variant on the risk of other cancers may be revealing.

Adult↗
PubMed2005

Association of NCOA3 polymorphisms with breast cancer risk.

The nuclear receptor coactivator 3 (NCOA3, also known as AIB1) is a coactivator of nuclear receptors like the estrogen receptor. NCOA3 is overexpressed in approximately 60% of primary human breast tumors, and high levels of NCOA3 expression are associated with tamoxifen resistance and worse survival rate. In contrast, NCOA3 deficiency suppresses v-Ha-ras-induced breast cancer initiation and progression in mice. Here, we analyzed the influence of NCOA3 coding single nucleotide polymorphisms on breast cancer risk by performing a case-control study using a German and a Polish study population and identified an association between NCOA3 polymorphisms and breast cancer. A joint analysis of the German and the Polish study population revealed a significant protective effect for the 1758G>C (Q586H) and 2880A>G (T960T) variants. In addition, haplotype analysis showed a protective effect of the 1758C-2880A and 1758G-2880G haplotypes (odds ratio 0.79; 95% confidence interval, 0.67-0.93; P = 0.004). Because of the impact of NCOA3 in antiestrogen therapy resistance, these polymorphisms might also influence therapy outcome in breast cancer.

Acetyltransferases↗
PubMed2005

In vitro analysis of matrix proteins and growth factors in dedifferentiating human chondrocytes for tissue-engineered cartilage.

CONCLUSIONS: With ongoing culture and dedifferentiation of chondrocytes, significant changes in the expression patterns of various collagens and the insulin-like growth factor (IGF) receptor were detected. The latter could play an important role in the differentiation of human chondrocytes. OBJECTIVE: Tissue engineering represents a promising method for the construction of autologous chondrogenic grafts for reconstructive surgery. So far, little is known about the expression of markers for cell proliferation and differentiation in cultured chondrocytes. MATERIAL AND METHODS: Human chondrocytes were isolated from septal cartilage (n=5) and held in primary cell culture. Cells were harvested after 24 h and 6 days. Proliferation was analyzed using an Alamar Blue assay. The differentiation of the cells was investigated using bright field microscopy, the expression patterns of various proteins using immunohistochemistry and the expression of distinct genes using a microarray technique. RESULTS: The chondrocytes showed strong proliferation (Day 0: 16.7+/-0.7 fluorescent units; Day 5: 52.4+/-2.2 fluorescent units) from the third day of cell culture in medium without growth factors. From this point onwards, a dedifferentiation of the chondrocytes could be observed. In cell culture, the chondrocytes expressed collagen 1 and 10 without expression of collagen 3. After 6 days of cell culture, they expressed collagen 2. The chondrocytes showed constant low expression of the fibroblast growth factor-2 receptor, but constant high expression of vascular endothelial growth factor, matrix metalloproteinase (MMP)2 and MMP9. The cells never expressed the epidermal growth factor receptor. The proportion of IGF receptor-expressing cells diminished significantly during cell culture.

Cartilage↗
PubMed2005

Molecular basis of the JAHK (RH53) antigen.

BACKGROUND: The JAHK antigen was first described in 1995 as a low-frequency red blood cell antigen. Family studies confirmed the association of the antigen with the rare r(G) phenotype of the Rh blood group system, which is associated with weak expression of C and e, but normal G expression. JAHK was allocated the Rh number RH53. The serologic findings indicated the location of the antigen on the RhCE protein, although the molecular basis for JAHK has not been known. STUDY DESIGN AND METHODS: The RHCE gene of eight persons from three unrelated families was analyzed by exon amplification and direct sequencing. Four of the samples were JAHK+ the remaining four were JAHK-. In one JAHK+ sample, the entire RHCE gene was sequenced. The remaining samples were sequenced for exons 1 to 3. A polymerase chain reaction procedure with sequence specific primers was developed for the specific detection of the JAHK allele. RESULTS: Analysis of the entire RHCE gene of one JAHK+ sample showed the expected CcEe-specific nucleotide sequences and revealed an additional nucleotide change (365C>T) in exon 3. This change represented a missense mutation, which led to an amino acid substitution from serine to leucine at position 122 of the RhCE protein. Three JAHK+ samples from two other unrelated families showed the 365C>T mutation and confirmed the association of the Ser122Leu substitution with the JAHK+ phenotype. CONCLUSION: The molecular basis of the JAHK antigen (RH53) is defined by a 365C>T mutation in exon 3 of the RHCE gene leading to the amino acid substitution Ser122Leu. Because the position 122 is predicted to be located in the transmembrane region adjacent to the second loop, the substitution of the neutral serine by the hydrophobic leucine seems to be the cause of the JAHK antigen by a conformational change of the RhCE protein. This structural change may also cause the weakened expression of the C and e antigens observed in JAHK+ individuals. Based on our results it is concluded that the JAHK-specific mutation is associated with a dCe haplotype.

Amino Acid Substitution↗
PubMed2005

Polymerase chain reaction inhibition assay documenting the amotosalen-based photochemical pathogen inactivation process of platelet concentrates.

BACKGROUND: The INTERCEPT Blood System (Baxter Healthcare Corp.) for platelets (PLTs) uses amotosalen-HCl (S-59) in conjunction with ultraviolet A (UVA) light to inactivate contaminating pathogens by modifying the nucleic acids of pathogens. The success of this photochemical treatment (PCT) process can be documented indirectly with a high-performance liquid chromatography assay measuring the photodegradation of amotosalen and measurement of the UVA light dose delivered by the illumination system. STUDY DESIGN AND METHODS: To develop an assay that documents the success of PCT directly on the effector molecule DNA, the effect of PCT on PLT-derived mitochondrial DNA (mtDNA) was examined. mtDNA-specific polymerase chain reaction (PCR) assays were tested with regard to their susceptibility for PCT, their reliability in terms of PCR performance, and the absence of polymorphic sites in primer hybridization loci. RESULTS: Suitable PCR amplification targets were found in the regions of 16S rDNA, cytochrome c oxidase I, and cytochrome c oxidase III of mitochondria. Amplicon sizes between 868 and 1248 bp gave consistent signals before PCT and complete inhibition of the PCR signal after PCT. Amplicons of less than 300 bp were found to be transparent to PCT. CONCLUSION: Based on PCT-mediated mtDNA modifications in PLTs, a PCR inhibition assay was established with a large amplicon documenting the success of PCT and a small amplicon serving as an internal control.

Adenine↗
PubMed2005

Microarray-based genotyping for blood groups: comparison of gene array and 5'-nuclease assay techniques with human platelet antigen as a model.

BACKGROUND: Most blood group alloantigens specific for red cells and platelets (PLTs) are based on single-nucleotide polymorphisms (SNPs) in genes encoding relevant membrane proteins. STUDY DESIGN AND METHODS: By use of five human PLT antigen (HPA) systems as a model, the suitability of a fourth-generation microarray technique for SNP typing was investigated. The results of the former were compared with those of a parallel developed third-generation technique (TaqMan assay, Applied Biosystems). Both techniques were validated by use of a unique panel of 71 blinded DNA samples containing at least 15 aa, bb, and ab genotypes for the HPA-1, -2, -3, -5, and-15 systems. RESULTS: Unambiguous and concordant results were obtained with both techniques for all samples. CONCLUSION: The data presented here validate the use of microarray for large-scale SNP typing for clinically relevant blood group alloantigens.

Antigens, Human Platelet↗