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Barbara Seliger

Publications and source records attributed to Barbara Seliger.

49 records · Page 3Linked to original sources
PubMed2003

Detection of renal cell carcinoma-associated markers via proteome- and other 'ome'-based analyses.

Proteome analysis has rapidly developed in the post-genome era and is now widely accepted as the complementary technology for genetic profiling. It has been shown to be a powerful tool for studying human diseases and for identifying novel prognostic, diagnostic and therapeutic markers. This review focuses on the identification of new biomarkers and therapeutic targets for renal cell carcinoma using different 'ome'-based technologies.

Biomarkers, Tumor↗
PubMed2003

Upregulation of major histocompatibility complex class I on liver cells by hepatitis C virus core protein via p53 and TAP1 impairs natural killer cell cytotoxicity.

The mechanisms of immune evasion and the role of the early immune response in chronic infection caused by hepatitis C virus (HCV) are still unclear. Here, we present evidence for a cascade of molecular events that the virus initiates to subvert the innate immune attack. The HCV core protein induced p53-dependent gene expression of TAP1 (transporter associated with antigen processing 1) and consecutive major histocompatibility complex (MHC) class I upregulation. Moreover, in p53-deficient liver cell lines, only reconstitution with wild-type p53, but not mutated p53 lacking DNA binding capacity, showed this effect. As a consequence of increased MHC class I expression, a significantly downregulated cytotoxic activity of natural killer (NK) cells against HCV core-transfected liver cells was observed, whereas lysis by HCV-specific cytotoxic T cells was not affected. These results demonstrate a way in which HCV avoids recognition by NK cells that may contribute to the establishment of a chronic infection.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2003

Characterization of human lymphocyte antigen class I antigen-processing machinery defects in renal cell carcinoma lesions with special emphasis on transporter-associated with antigen-processing down-regulation.

The HLA class I antigen-processing machinery (APM) plays a crucial role in the generation of peptides from endogenously synthesized proteins and in their presentation to cytotoxic T lymphocytes. The potential role of defects of APM components in immune escape mechanisms used by malignant cells has prompted us to analyze their expression in renal cell carcinoma (RCC) lesions with special emphasis on TAP because of its critical role in the loading of HLA class I antigens with peptides. Immunohistochemical staining of 51 formalin-fixed RCC lesions and autologous normal renal epithelium detected transporter associated with antigen processing (TAP)1 and tapasin deficiencies in 63 and 80% of the tumor lesions. Impaired low molecular weight protein (LMP)2 and LMP7 expression was found in 73 and 33% of the RCC lesions analyzed, respectively. In contrast to the high frequency of APM component down-regulation, HLA class I heavy chain and beta(2)-microglobulin defects were detected in only 12 and 10% of the lesions, respectively. Concomitant TAP1 and LMP2 deficiencies were found in approximately 57% of RCC lesions, whereas a coordinated down-regulation of all APM components occurred only in 5% of the tumor specimens analyzed. The presence of APM defects was independent of tumor stage and grade but varied significantly among the RCC subtypes. TAP abnormalities do not appear to be attributable to structural alterations because no mutations in TAP1 were detected in TAP1-deficient RCC lesions. These data suggest that TAP defects in RCC lesions are caused by regulatory abnormalities. Therefore, T-cell-based immunotherapy may benefit from the administration of cytokines that up-regulate TAP expression.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2003

Analysis of the structural integrity of the TAP2 gene in renal cell carcinoma.

The transporter associated with antigen processing (TAP) gene products is involved in the processing of endogenous peptides that bind to MHC class I molecules. Mutations and/or polymorphism within these genes could alter the efficacy of the immune response which might be relevant for the development of autoimmune diseases and cancer. In this study we examined both the structural integrity and the polymorphism of TAP2 in renal cell carcinoma lesions by sequencing TAP2 in renal cell carcinoma lesions and autologous normal kidney epithelium. TAP2 sequence analysis of 31 renal cell carcinoma lesions, one oncocytoma and respective autologous normal kidney epithelium revealed no mutation in the TAP2 gene, whereas a TAP2 polymorphism was detected at position -36 up-stream of the ATG. This polymorphism is heterozygous in about 66% of the lesions analyzed. In addition, heterozygosity at base pair position 1797 downstream of the ATG was found, which did not affect the amino acid composition. The distribution of the TAP2 alleles analyzed in the different lesions demonstrated a 48.4% homozygosity of the tumors regarding different N-SNPs. Most of the known S-SNPs showed 61.3% heterozygosity independent of a particular allele. Thus, TAP2 gene polymorphism is not linked to renal cell carcinoma since no association between a particular amino acid residue and the disease was found.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2002

Long-term freedom from recurrence in 2 stage IV melanoma patients following vaccination with tyrosinase peptides.

We report here on 2 patients who received adjuvant vaccination with an HLA-A2- or HLA-A24-restricted tyrosinase peptide, respectively, and GM-CSF for frequently relapsing stage IV melanoma. Following resection of metastases and irradiation of brain metastases in 1 patient, both patients were without evidence of disease when receiving the first vaccination. While the patients had had 9 and 12, respectively, mostly s.c., relapses during the 3 years before vaccination, they experienced freedom from relapse for more than 2 years after vaccination. We found a T-cell response to the vaccine peptide in both patients in the peripheral blood by ex vivo IFN-gamma ELISPOT assay. The T-cell population could be further characterized by 4-color flow cytometry in 1 patient, showing that the majority of the peptide-specific CD3(+)CD8(+)IFN-gamma(+) T cells were granzyme B-positive and CCR-7-negative, characterizing them as effector T cells with the ability to mediate cytotoxicity and migrate to inflamed tissues. In this patient also, augmentation of the T-cell response to autologous tumor cells by vaccination could be detected. A single-site postvaccination relapse occurred in both patients, showing downregulation of tyrosinase expression in 1 patient, while normal expression levels for tyrosinase, MHC class I antigens and components of the antigen-processing machinery were found in the other patient. These results suggest that peptide vaccination resulted in a prolonged relapse-free interval in these high-risk patients.

Brain Neoplasms↗
PubMed2002

Increased tumorigenicity, but unchanged immunogenicity, of transporter for antigen presentation 1-deficient tumors.

The lack of transporter-for-antigen-presentation (TAP)-1 expression by tumor cells prevents the processing and presentation of MHC class I-restricted tumor antigens. This could affect T-cell-dependent tumor immunity in either the priming or the effector phase. We have established TAP1(+) and TAP1(-) tumor cell lines using ras-transformed NIH3T3 fibroblasts. Impaired TAP1 expression by tumor cells increased their tumorigenicity in immunocompetent, but not in T-cell-deficient, mice. For the generation of tumor immunity, TAP1 expression was not necessary on tumor cells used for vaccination. However, in previously immunized mice TAP1(+) tumor cells were more efficiently rejected than were TAP1(-) tumor cells. CD8(+) T cells infiltrated both TAP1(+)- and TAP1(-)-challenge tumors and were required for tumor rejection. In mixed tumor/lymphocyte culture, TAP1 expression by tumor cells significantly increased the IFN-gamma production of antigen-specific spleen cells from immunized, but not from naive, mice. Thus, the lack of TAP1 expression did not change the immunogenicity of tumor cells. It may enable tumor cells to escape T-cell recognition during the effector phase of an antitumor immune response.

3T3 Cells↗
PubMed2002

Heat shock protein expression and anti-heat shock protein reactivity in renal cell carcinoma.

Heat shock proteins (HSP) are families of highly conserved proteins which are induced in cells and tissues upon exposure to extreme conditions causing acute or chronic stress. They exhibit distinct functions and have been implicated in the pathogenesis of a number of diseases, including cancer. A causal relationship between HSP expression and immunogenicity has been demonstrated in murine and human tumors and is also associated with the immune response. In order to investigate the correlation of HSP expression and their immunogenic potential in renal cell carcinoma (RCC), we here analyzed (i) the protein expression profile of various members of the HSP family in untreated and interferon (IFN)-gamma treated RCC cell lines as well as normal kidney epithelium, and (ii) the anti-heat shock protein reactivity in sera derived from RCC patients and healthy controls using proteomics-based techniques. A heterogeneous expression pattern of members of the HSP families was demonstrated in RCC cell lines and in cells representing normal renal epithelium. In some cases the expression rate is moderately altered by IFN-gamma treatment. In addition, a distinct anti-heat shock protein reactivity could be detected in autologous and allogeneic sera from RCC patients and healthy controls. These data suggest that HSP play a role in the immunogenicity of RCC and thus might be used for the design of immunization strategies to induce a potent antitumor response in this disease.

Animals↗
PubMed2002

Design of proteome-based studies in combination with serology for the identification of biomarkers and novel targets.

Recently proteome analysis has rapidly developed in the post-genome era and is now widely accepted as a complementary technology to genetic profiling. The improvement in the technology of both two-dimensional electrophoresis (2-DE) analysis as well as protein identification has made proteomics a valuable and powerful tool to study human diseases. A combination of conventional proteome analysis with serology has been developed as a promising experimental approach for the discovery of serological markers in different malignancies. However, the design of proteome-based studies has to be carefully performed since there are a number of critical needs for systematic and reproducible proteome analysis. In particular, the selection of tissue and its preparation represent an important step in proteome analysis. Besides the preparation of protein samples, the 2-DE and protein identification is a further critical issue. So far proteome-based technologies have been successfully used in tumor immunnology for the identification of tumor-specific autoantigens. Similarly, this technology has been employed for the detection of virulence factors, antigens and vaccine candidates in infectious diseases, as well as for the identification of diagnostic and prognostic markers, suggesting that proteome-based analysis is a promising tool for the identification of prognostic, diagnostic markers as well as for novel therapeutic targets which could be used for treatment of diseases. The integration of proteome-based approaches with data from genomic or genetic profiling will lead to a better understanding of different diseases, which will then contribute to the direct translation of the research findings into clinical practice.

Antigens, Neoplasm↗
PubMed2002

Targeting of tumor associated antigens in renal cell carcinoma using proteome-based analysis and their clinical significance.

The suitability of proteome-based strategies for the targeting of tumor-associated markers along with further analysis regarding their clinical significance were investigated in human renal cell carcinoma (RCC). The immunogenic protein expression profile of normal kidney and RCC cell lines was studied by proteome analysis combined with immunoblotting using sera from healthy donors and RCC patients, also termed PROTEOMEX. Employing this approach, a series of proteins reactive with either RCC patient sera and/or reactive with control sera were identified by microanalysis of tryptic peptides. Some of these candidate antigens represent members of the cytoskeletal family, such as cytokeratins, in particular cytokeratin 8, cytoskeletal tropomyosin, F-actin capping protein, gamma-actin, stathmin, tubulin-alpha, tubulin-beta and vimentin. The expression pattern and clinical significance of three of these antigens, namely cytokeratin 8, stathmin and vimentin, were further analyzed in a large series of surgically removed RCC lesions of distinct subtypes. A heterogeneous expression pattern of cytokeratin 8, stathmin and vimentin was demonstrated in the different RCC subtypes. All epithelial cells of the autologous normal kidney showed a strong cytokeratin 8 staining pattern, whereas they totally lack vimentin expression. Stathmin was expressed in 10% of tubule cells. In conclusion, PROTEOMEX could be employed for the identification of tumor-associated antigens of the cytoskeleton which are differentially expressed in RCC of distinct subtypes as well as in normal renal epithelium.

Antigens, Neoplasm↗
PubMed2002

High frequency of a non-functional TAP1/LMP2 promoter polymorphism in human tumors.

The Tap1 and Tap2 genes encoding for a heterodimeric peptide transporter play a key role in antigen processing and presentation. The TAP complex mediates the transport of peptides generated by the IFN-gamma-inducible proteasome subunits LMP2, 7 and 10 from the cytosol into the endoplasmic reticulum (ER), where they bind to MHC class I molecules. In contrast to the frequent polymorphisms within the rat Tap genes which exert functional differences, polymorphic regions within the human Tap genes have been demonstrated, but not systematically analyzed in terms of their functional significance. Both the Tap1 and Lmp2 genes are transcribed from a bidirectional intergenic promoter which is regulated by at least three sequences located in the Tap1 proximal region. We describe here a polymorphic site in the shared TAP1/LMP2 promoter which frequently occurred in human tumor cells of distinct origin. This polymorphism resulted in a Gright curved arrow T substitution 151 bp upstream of the translation start of Tap1. Using transient transfection assays with luciferase reporter constructs, the transcriptional activities of the different allelic variants of the TAP1/LMP2 promoter were comparable suggesting no functional consequences of this TAP1/LMP2 promoter polymorphism.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2002

5-aza-2'-deoxycytidine-induced expression of functional cancer testis antigens in human renal cell carcinoma: immunotherapeutic implications.

PURPOSE: Limited therapeutic options are presently available for advanced renal cell carcinoma (RCC). This study was designed to define the clinical potential of the DNA hypomethylating agent 5-aza-2'-deoxycytidine (5-AZA-CdR) in human RCC, through its control of the expression of "therapeutic targets" of the cancer testis antigen (CTA) family, and of the tumor-associated antigen RAGE-1, in RCC cells. EXPERIMENTAL DESIGN: Reverse transcription (RT)-PCR assays of a panel of RCC cells treated with 5-AZA-CdR, investigated the induction of the expression of several CTAs and of RAGE-1. Immunoprecipitation and Western blotting assessed whether the expression of CTA-specific mRNA induced by 5-AZA-CdR resulted in a translated protein of appropriate molecular weight. The functional activity of de novo expressed CTA was evaluated using (51)Cr release cytotoxicity assays of 5-AZA-CdR-treated HLA-A2-positive RCC cells using HLA-A2-restricted NY-ESO-1-specific CTLs. RESULTS: Exposure to 5-AZA-CdR invariably induced the expression of the CTA MAGE-1, -2, -3, and -4, GAGE 1-6, and NY-ESO-1 in all of the RCC cells investigated. De novo expression of NY-ESO-1 was persistent, being still detectable 60 days after the end of treatment, and generated a functional protein efficiently recognized by HLA-A2-restricted NY-ESO-1-specific CTLs. 5-AZA-CdR also induced RAGE-1 expression in RAGE-1-negative RCC and sarcoma cells but not in neoplastic cells of different histology. CONCLUSIONS: This study provides the scientific rationale to establish new strategies of chemoimmunotherapy in RCC patients. The well-defined immunogenicity of the investigated CTAs and of RAGE-1 suggest that systemic administration of 5-AZA-CdR represents a promising strategy to enhance the constitutively poor immunogenic potential of RCC cells, and to propose that virtually all RCC patients receive active and/or adoptive CTA- or RAGE-1-based immunotherapy.

Antibodies, Monoclonal↗