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D Schadendorf

Publications and source records attributed to D Schadendorf.

At least 19 recordsLinked to original sources
PubMed2002

Cutaneous large B-cell lymphoma of the leg masquerading as a chronic venous ulcer.

We report on a 74-year-old female patient with a primary cutaneous CD20+, diffuse large cell B-cell lymphoma of the lower leg resembling a chronic non-healing leg ulcer. There was no evidence of systemic involvement on computed tomography (CT) scans of the chest, abdomen and pelvis; a slightly enlarged lymph node in the right groin showed dermatopathic lymphadenopathy on histology and immunohistochemistry. Involvement of the bone marrow and peripheral blood was ruled out by punch biopsy and fluorescent activated cell sorter (FACS) analysis of the blood, respectively. Therapeutic anti-CD20 monoclonal antibody rituximab was given at 375 mg m(-2) i.v. once weekly for 7 weeks, without adverse effects, resulting in a minor improvement in the centre of the ulcerated tumour. Unfortunately, the response was not maintained, and after 7 weeks of treatment the patient started to develop new tumour lesions at the border of the ulcer. Local radiotherapy was started and combined photon and electron beam irradiation induced complete remission of the B-cell lymphoma.

Aged↗
PubMed2001

Drug-resistance in human melanoma.

Advanced malignant melanoma has a poor prognosis since chemotherapy is mostly ineffective due in part to the intrinsic and/or extrinsic resistance of melanoma cells to systemic treatment with anti-neoplastic agents. The reasons for the chemoresistant phenotype are unknown. The relevance of well-analyzed drug-resistance mechanisms, e.g., intracellular/extracellular transport and induction of certain enzyme systems, is reviewed. Most anti-cancer drugs kill susceptible cells through induction of apoptosis. Therefore, it appears that differences in the apoptotic pathways which lead to apoptotic deficiency may account for the ability of some tumor cells to resist drug therapy. Human melanomas, which are characteristically drug-resistant, are more likely to have altered apoptotic pathways and fewer pro-apoptotic molecules. Tumor cells with these characteristics are seldom sensitive to drugs. The complexity of the molecular variants involved in signal transduction along apoptotic pathways suggests that the cell may have a variety of possibilities for regulating apoptosis and generating apoptotic deficiency. Thus, apoptosis and apoptotic deficiency should be analyzed to better clarify the mechanisms of melanoma resistance.

Apoptosis↗
PubMed2001

Enhanced expression of human ABC-transporter tap is associated with cellular resistance to mitoxantrone.

Multidrug resistance (MDR) phenotypes have been associated with the overexpression of various members of the superfamily of ATP binding cassette (ABC) transporters. Here we demonstrate that a member of the ABC-transporter family, the heterodimer 'transporter associated with antigen processing' (TAP), physiologically involved in major histocompatibility complex class I-restricted antigen presentation, is significantly overexpressed in the human gastric carcinoma cell line EPG85-257RNOV exhibiting a mitoxantrone-resistant phenotype. This tumor cell line shows an atypical MDR phenotype in the absence of 'P-glycoprotein' or 'MDR-associated protein' overexpression but with an enforced 'breast cancer resistance protein' expression level. Transfection of both TAP subunits encoding cDNA molecules, TAP1 and TAP2, into the drug-sensitive parental gastric carcinoma cell line EPG85-257P conferred a 3.3-fold resistance to mitoxantrone but not to alternative anti-neoplastic agents. Furthermore, cell clones transfected with both, but not singularly expressed TAP1 or TAP2, reduced cellular mitoxantrone accumulation. Taken together, the data suggest that the heterodimeric TAP complex possesses characteristics of a xenobiotic transporter and that the TAP dimer contributes to the atypical MDR phenotype of human cancer cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

DFNA5 (ICERE-1) contributes to acquired etoposide resistance in melanoma cells.

Resistance to drug treatment is a common observation in malignant melanoma. In order to analyze alterations in mRNA expression profiles associated with drug resistance in melanoma cells we previously established a panel of various drug-resistant cell variants derived from the human melanoma line MeWo and compared the mRNA expression profiles by a differential display technique. By that approach it could be demonstrated that the expression level of a mRNA encoded by a gene found to be mutated in non-syndromic hearing impairment, DFNA5 (ICERE-1), was distinctly decreased in the 33-fold etoposide-resistant melanoma cell line MeWo ETO 1. To evaluate the hypothesis that a decrease in DFNA5 mRNA expression level contributes to the acquired etoposide resistance phenotype exhibited by MeWo ETO 1 cells, this drug-resistant line was stably transfected with the DFNA5-encoding cDNA. Transfected clones showed a 30-35% reduced etoposide susceptibility by comparing the IC(25), IC(50) and IC(75) values of these clones with those displayed by the non-transfected, etoposide-resistant melanoma cell line MeWo ETO 1 and controls. Furthermore, etoposide exposure of stable DFNA5 transfectants resulted in an increase of caspase-3-mediated apoptotic events in DFNA5-transfected clones in comparison to MeWo ETO 1 cells and controls. The data therefore demonstrate that a decrease in DNFA5 mRNA expression level is associated with an increased etoposide resistance in melanoma cells due to an elevated cellular susceptibility to trigger a caspase-3-depending signal pathway leading to programmed cell death.

Antineoplastic Agents, Phytogenic↗
PubMed2001

Acquired resistance of melanoma cells to the antineoplastic agent fotemustine is caused by reactivation of the DNA repair gene MGMT.

Acquired resistance to antineoplastic agents is a frequent obstacle in tumor therapy. Malignant melanoma cells are particularly well known for their unresponsiveness to chemotherapy; only about 30% of tumors exhibit a transient clinical response to treatment. In our study, we investigated the molecular mechanism of acquired resistance of melanoma cells (MeWo) to the chloroethylating drug fotemustine. Determination of O(6)-methylguanine-DNA methyltransferase (MGMT) activity showed that MeWo cells that acquired resistance to fotemustine upon repeated treatment with the drug display high MGMT activity, whereas the parental cell line had no detectable MGMT. The resistant cell lines exhibit cross-resistance to other O(6)-alkylating agents, such as N-methyl-N'-nitro-N-nitrosoguanidine. Acquired resistance to fotemustine was alleviated by treatment with the MGMT inhibitor O(6)-benzylguanine demonstrating that reactivation of MGMT is the main underlying cause of acquired alkylating drug resistance. As compared with control cells, both MGMT mRNA and MGMT protein were expressed at a high level in fotemustine resistant cells. Southern blot analysis proved that the MGMT gene was not amplified. There was also only an insignificant difference in the CpG methylation pattern of the MGMT promoter whereas a clear hypermethylation in the body of the gene was observed in fotemustine resistant cells. The conclusion that hypermethylation is responsible for reactivation of the MGMT gene gained support by the finding that MGMT activity significantly declined and cells reverted (partially) to the parental sensitive phenotype upon treatment with 5-azacytidine. This is the first report of acquired resistance to a chloroethylating antineoplastic drug of melanoma cells due to gene hypermethylation.

Antineoplastic Agents↗
PubMed2001

Serological detection of cutaneous T-cell lymphoma-associated antigens.

Cutaneous T-cell lymphomas (CTCL) are a group of skin neoplasms that originate from T lymphocytes and are difficult to treat in advanced stages. The present study is aimed at the identification of tumor-specific antigens from a human testis cDNA library using human sera known as the SEREX (serological identification of recombinantly expressed genes) approach. A cDNA library from normal testicle tissue was prepared and approximately 2 million recombinants were screened with sera from Sézary Syndrome and Mycosis fungoides patients. A total of 28 positive clones belonging to 15 different genes/ORFs were identified, including five hitherto unknown sequences. Whereas control sera did not react with most clones, 11-71% sera from CTCL patients were reactive against the identified clones. Expression analysis on 28 normal control and 17 CTCL tissues by reverse transcription-PCR (RT-PCR) and Northern blotting revealed seven ubiquitously distributed antigens, six differentially expressed antigens (several normal tissues were positive), and two tumor-specific antigens that were expressed only in testis and tumor tissues: (i) A SCP-1-like sequence, which has already been detected in various tumors, has been found in one CTCL tumor and four sera of CTCL patients reacted with various SCP-1-like clones and (ii) a new sequence named cTAGE-1 (CTCL-associated antigen 1) was detected in 35% of CTCL tumor tissues and sera of 6/18 patients reacted with this clone. The present study unravels CTCL-associated antigens independent of the T-cell receptor. The SCP-1-like gene and cTAGE-1 were shown to be immunogenic and immunologically tumor-specific and may therefore be candidates for immunotherapy targeting CTCL.

Antibodies, Neoplasm↗
PubMed2001

Autologous dendritic cells for treatment of advanced cancer--an update.

Dendritic cells (DC) are commonly viewed as the professional antigen-presenting cell. They capture antigens, migrate to appropriate lymphoid organs and initiate an antigen-specific CD4 and CD8 T cell response. Much is known about DC physiology, and it is now possible to culture, maintain and expand DC from different human sources, including hematopoietic progenitors in bone marrow and peripheral blood. Combined with the detection of an increasing number of tumor-associated antigens and T cell-recognized peptide epitopes, this has led to a new enthusiasm in the field of tumor immunotherapy and to various clinical applications in phase I/II studies on the treatment of different malignancies. This chapter will review the latest developments and give a brief update of the results obtained in studies of advanced melanoma, as well as provide a short overview of published results for other tumors.

Animals↗
PubMed2001

Segregation of effector mechanisms in a tumour-specific CD8+ T-cell clone correlates with CD30 expression.

In this study we have analyzed CD30-antigen expression in three melanoma-directed cytotoxic T lymphocyte (CTL) clones with a T helper 0 (Th0)-like cytokine secretion profile (i.e. interleukin (IL)-4, IL-5, and interferon (IFN)-gamma). We show that all CTL clones expressed high levels of CD30 upon contact with the autologous tumour cells. One CTL clone, termed A2 with a monoclonal feature was selected for further analyses and found its CD30 expression dependent on the presence of IL-4. Functionally, a CD30-expressing A2 CTL was capable of producing higher amounts of IFN-gamma (up to 1.5-fold) and IL-4 (up to two-fold) than its CD30- counterpart. Furthermore, CD30-positive A2 CTL displayed an at least three-fold greater proliferative response to the tumour cell stimulation, contrasting with CD30- CTL. However, the antitumour cytotoxic activity of A2 CTL was not modulated by the CD30 expression. These results suggest that CD30 antigen can be inducible on a subset of tumour-directed CD8+ CTL, and that this subset of cells may have profound effector functions, such as cytokine secretion, proliferation, and cytotoxicity.

Cell Line, Transformed↗
PubMed2001

Expression of cyclins and cyclin dependent kinases in human benign and malignant melanocytic lesions.

AIMS: The regulation of cell proliferation is a key event in normal development, pathophysiological responses to injury, and tumorigenesis. The orderly progression of cells through the cell cycle depends on a finely tuned balance between the concentrations of activated cyclins and cyclin dependent kinases. This study was undertaken to compare the expression of cell cycle regulators in benign and malignant melanocytic lesions during tumour progression. METHODS: Immunohistochemistry was used to analyse 49 primary cutaneous malignant melanomas, 18 metastatic melanomas, and 12 histologically confirmed naevus cell naevi for their expression of cyclins (A, B1, D1, D2, D3, and E) and cyclin dependent kinases (CDK1, CDK2, and CDK4). RESULTS: Cyclin E and CDK2 had the highest expression patterns in human cutaneous melanomas and metastases and correlated positively with histological type and tumour stage. Cyclins B1, D2, and D3 had significantly increased expression in metastases, but normal or even decreased expression in primary melanomas. However, cyclins A and D1, and CDK1 and CDK4 were expressed very weakly in situ with no significant differences between naevi, melanomas, or metastases, and there was no correlation with histopathological staging. The specificity of recognition by the antibodies used was confirmed by western blotting on a panel of seven human melanoma cell lines. Cyclins A, B, and E were expressed by all seven, whereas cyclin D1 was detectable in six of seven and CDK2 and cdc2 were present in five of seven lines analysed. CONCLUSIONS: Taken together, this study demonstrated a significant increase of cyclin E and CDK2 expression during tumour progression in malignant melanomas.

Biomarkers, Tumor↗
PubMed2000

Identification of differentially expressed genes in human melanoma cells with acquired resistance to various antineoplastic drugs.

Malignant melanoma displays strong resistance against various antineoplastic drugs. The mechanisms conferring this intrinsic resistance are unclear. To better understand the molecular events associated with drug resistance in melanoma, a panel of human melanoma cell variants exhibiting low and high levels of resistance to 4 commonly used drugs in melanoma treatment, i.e., vindesine, etoposide, fotemustine and cisplatin, was characterized by differential display reverse transcription-polymerase chain reaction (DDRT-PCR). Of 269 mRNA fragments found to be altered in expression level by DDRT-PCR, a total of 11 cDNA clones was characterized after confirmation of a differential expression pattern by Northern blot analyses. These clones include 3 genes (DSM-1, DSM-3 and DSM-5) of known function, 4 previously sequenced genes (DSM-2, DSM-4, DSM-6 and DSM-7) of uncharacterized function and 4 novel genes (DSM-8-DSM-11) without match in GenBank. All of these genes exhibited altered mRNA expression in high level etoposide-resistant cells, whereby 7 genes (DSM-1-DSM-6 and DSM-8) were found to be decreased in the transcription rate in these etoposide-resistant cells. The mRNA synthesis of the remaining genes (DSM-7 and DSM-9-DSM11) was enhanced in high level etoposide-resistant melanoma cells. The expression of 5 (DSM-5 and DSM-7-DSM-10) of the cloned cDNA encoding mRNAs was modulated in various independently established drug-resistant melanoma cells, indicating to be associated with drug resistance. Further characterization of these genes may yield inside into the biology and development of drug resistance in malignant melanoma.

Antineoplastic Agents↗
PubMed2000

Autologous, allogeneic tumor cells or genetically engineered cells as cancer vaccine against melanoma.

Melanoma is a prototype of immunogenic tumor to which various types of immunotherapy have been applied extensively over the past decades. Melanoma vaccines are designed for the purpose of immune modulation and subsequent anti-tumor effects in the process of an active specific immunotherapy. Previous attempts of these vaccines include immunization with whole tumor cells/cell lysates admixed with nonspecific adjuvants. While these vaccines generated enhanced anti-tumor immunity in a subset of patients, some of which showing prolonged survival compared to historical controls, no clinical benefit has so far been demonstrated in a properly controlled phase III study. New-generation melanoma vaccines, which are based on genetic modifications of tumor cells to express cytokines, generated long-lasting systemic anti-tumor immunity in animal models. Translation of these preclinical results primarily into melanoma patients with advanced diseases, shows the potential of these vaccines to induce systemic anti-tumor immune responses and in some instances tumor regression with acceptably low toxicity. Higher efficacy of this novel vaccine approach would be expected when used in a postsurgical adjuvant setting when the tumor load is small. Also other novel vaccine approaches such as dendritic cell-based therapy hold promise for the treatment of melanoma. But the clinical value of all these new approaches has to be analysed in prospectively randomized clinical studies.

Antigens, Neoplasm↗
PubMed2000

High frequencies of circulating melanoma-reactive CD8+ T cells in patients with advanced melanoma.

To determine whether circulating tumor-reactive T cells are present in melanoma patients, unstimulated T cells from peripheral blood were tested for recognition of HLA-A2- or HLA-A1-matched melanoma cell lines using the ELISPOT assay. Eleven out of 19 patients with metastatic melanoma had a T-cell response with up to 0.81%, 0.78%, 0. 53%, 0.12%, 0.10%, 0.09%, 0.07%, 0.06%, 0.06%, 0.04%, and 0.04% of peripheral blood mononuclear cells (PBMC) secreting IFNgamma upon exposure to various HLA-A2- or HLA-A1-matched melanoma cell lines. These T-cell responses were mediated by CD8+ T cells and could specifically be blocked by an anti-HLA-A2 antibody in HLA-A2-positive patients. Separation experiments performed in one melanoma patient showed tumor-reactive T cells in both the CD8+ effector T cell (CD45RA+/IFNgamma+) as well as the CD8+ memory T-cell compartment (CD45RO+/IFNgamma+). In 3 out of 5 patients, in whom autologous cell lines were available, similar frequencies of T cells in response to HLA-A1- or HLA-A2-matched allogeneic and autologous tumor cells were observed, while 2 patients had a T-cell response restricted to either the autologous or the allogeneic cell lines. These results give evidence for the presence of tumor-reactive CD8+ T cells in more than half of melanoma patients tested. Although some of these patients have clinical evidence for an immunological-mediated tumor control, several patients have growing tumors suggesting presence of escape mechanisms.

Antigens, Neoplasm↗
PubMed2000

Identification of a new HLA-A(*)0201-restricted T-cell epitope from the tyrosinase-related protein 2 (TRP2) melanoma antigen.

For the development of peptide-based immunotherapies, the identification of additional tumor antigens and T-cell epitopes is required. Because HLA-A(*)0201 is the most common allele in Caucasians, who represent the majority of patients with melanomas, 6 peptides carrying an HLA-A(*)0201 motif were synthesized from tyrosinase-related protein-2 (TRP2) melanoma antigen and tested for binding affinity to the HLA allele using processing-defective T2 cells. These peptides were then pulsed onto autologous dendritic cells and used to stimulate in vitro CD8(+)-enriched T cells isolated from peripheral blood of HLA-A(*)02(+) healthy donors or melanoma patients for the induction of specific cytotoxic T lymphocytes (CTLs). One peptide, TRP2(288-296) (SLDDYNHLV), the best HLA-A(*)0201 binder, elicited specific CTLs from 1 of 4 patients and 3 of 4 healthy donors. The induced CTLs from the patient and from 1 donor efficiently recognized HLA-A(*)02(+) TRP2(+) melanomas as well as COS-7 cells expressing HLA-A(*)0201 and TRP2 in an HLA class I-restricted manner, as assessed by cytokine production and direct cytolysis. The remaining 2 CTL lines derived from 2 donors displayed low T-cell receptor avidity, which could lyse melanoma cells in the presence of exogenous peptide. Since TRP2 is an antigen expressed in most melanomas, identification of the TRP2/HLA-A(*)0201 peptide SLDDYNHLV may facilitate the design of present peptide-based immunotherapies for the treatment of a large fraction of melanoma patients.

Amino Acid Motifs↗