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J Eberle

Publications and source records attributed to J Eberle.

At least 19 recordsLinked to original sources
PubMed2006

Resistance of melanoma cells to TRAIL does not result from upregulation of antiapoptotic proteins by NF-kappaB but is related to downregulation of initiator caspases and DR4.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has attracted considerable attention as a novel anticancer agent. However, its efficiency may be diminished by occurring resistance in cancer cells. The mechanisms of TRAIL resistance in melanoma are still unsolved. Here we show for the first time that TRAIL-induced activation of NF-kappaB occurs in apoptosis-sensitive melanoma cell lines through TRAIL receptor 1/death receptor 4 (TRAIL-R1/DR4), whereas TRAIL failed to activate nuclear factor kappa B (NF-kappaB) in melanoma cells positive only for TRAIL receptor 2/death receptor 5 (TRAIL-R2/DR5). However, activation of NF-kappaB by TRAIL was not associated with enhanced expression of antiapoptotic factors: cellular FLICE-inhibitory protein (c-FLIP), Bcl-x(L), X-linked inhibitor of apoptosis protein (XIAP), Survivin, Livin. Rather in one of the cell lines, TRAIL induced the downregulation of DR4. In an established cell culture model for TRAIL resistance and regained TRAIL sensitivity, resistance was neither associated with increased NF-kappaB activity by TRAIL nor by an increased expression of antiapoptotic proteins. However, significant downregulation of caspase-8, caspase-10 and of DR4 was characteristic for TRAIL-resistant, DR4-positive melanoma cells, and regained TRAIL sensitivity coincided with re-expression of these factors. Sensitivity was also largely retained after their exogenous overexpression. Thus, initiator caspases and DR4 rather than NF-kappaB may control melanoma cell sensitivity to TRAIL, and strategies, which result in their upregulation, may be useful for enhancement of TRAIL sensitivity.

Apoptosis Regulatory Proteins↗
PubMed2006

A novel Bcl-x splice product, Bcl-xAK, triggers apoptosis in human melanoma cells without BH3 domain.

Pro- and antiapoptotic proteins of the large Bcl-2 family are critical regulators of apoptosis via the mitochondrial pathway. Whereas antiapoptotic proteins of the family share all four Bcl-2 homology domains (BH1-BH4), proapoptotic members may lack some of these domains, but all so far described proapoptotic Bcl-2 proteins enclose BH3. The bcl-x gene gives rise to several alternative splice products resulting in proteins with distinct functions as the antiapoptotic Bcl-xL and proapoptotic Bcl-xS. Here, we describe a novel Bcl-x splice product of 138 amino acids termed Bcl-xAK (Atypical Killer), which encloses the Bcl-2 homology domains BH2 and BH4 as well as the transmembrane domain, but lacks BH1 and BH3. Weak endogenous expression of Bcl-xAK was seen in melanoma and other tumor cells. Interestingly, its overexpression by applying a tetracycline-inducible expression system resulted in significant induction of apoptosis in melanoma cells, which occurred in synergism with drug-induced apoptosis. After exogenous overexpression, Bcl-xAK was localized both in mitochondrial and in cytosolic cell fractions. By these findings, a completely new class of Bcl-2-related proteins is introduced, which promotes apoptosis independently from the BH3 domain and implies additional, new mechanisms for apoptosis regulation in melanoma cells.

Alternative Splicing↗
PubMed2004

Vascular endothelial growth factor (VEGF) is increased in serum, but not in cerebrospinal fluid in HIV associated CNS diseases.

Vascular endothelial growth factor (VEGF) is a potent angiogenic and mitogenic peptide, which also induces several mediators that may play a role in HIV induced CNS damage. VEGF levels were determined in cerebrospinal fluid (CSF) and serum samples from patients with (n = 8) and without (n = 19) directly HIV associated CNS disorders and HIV negative control patients (n = 18). VEGF serum but not CSF levels were significantly increased in HIV infected patients with (381.1 (78.9) pg/ml) HIV associated CNS diseases compared with those without (120.8 (13.1) pg/ml) and HIV negative control patients (133.1(14.8) pg/ml). Serum samples from patients with untreated HIV associated encephalopathy (HIVE, n = 3) contained the highest VEGF levels (583.9 (71.5) pg/ml). In two patients VEGF serum levels were reduced during antiretroviral therapy. However, regardless of effective viral suppression, patients with HIVE still had higher levels compared with HIV infected patients without HIVE. A relevant increase of serum VEGF was not observed in patients without HIVE though high HI viral load. We conclude that HIVE is associated with increased serum VEGF levels. Further studies are warranted to elucidate the role of VEGF in HIVE.

AIDS Dementia Complex↗
PubMed2003

Amprenavir in pre-treated patients: virological and immunological response in a cohort of 45 patients.

Treatment failure after preceding protease inhibitors (PI) is often due to resistance mutations. Our objective was to evaluate amprenavir (APV) in pre-treated patients and to correlate it with pre-existing mutations. - Fourty five patients were entered in an open label prospective study (6/99-12/2000). Pre-treatment was 6.2 years +/- 2.4 (2-11.3) and included a mean of 4.13 nucleosides (RTIs) and 2.73 PIs. Genotypic resistance testing was performed prior to the switch. APV dose was 1200 mg/d in combination with ritonavir (RTV) boosting (2 x 100mg) and 2 x 1200 mg/d in 6 patients without RTV. Co-medication was selected based on treatment history and results of genotypic testing. - The median duration of treatment at analysis was 34 weeks. Plasma viral load (VL) average at baseline was 4.6 log subset 10 +/- 08. After 24 weeks the mean VL reduction was 1.4 log subset 10 +/- 1.2 3.86-0.40s). A VL reduction of >1.5 log subset 10 was found in 16/45 patients (36%), 21/45 (47%) patients achieved a VL <400 cp/ml, and 12/45 (27%) a VL < 50 cp/ml. CD4 cells increased from a mean baseline of 208/microl +/- 185 to 318/microl +/- 253. Fourty percent (18/45) of patients had a CD4 gain of more than 100 cells/microl. Genotypic resistance determination showed PI mutations in 87% of patients tested. The average number of mutated codons was 4.54. Three of 4 patients with I84V mutation did not achieve an undetectable VL. - Our findings demonstrate that APV and APV/RTV plus two additional antiretrovirals has a good virological and immunological success rate in pre-treated patients. Presence of more than two APV resistance mutations was associated with treatment failure.

Anti-HIV Agents↗
PubMed2003

Disease progression in patients with thin cutaneous melanomas (tumour thickness < or = 0.75 mm): clinical and epidemiological data from the Tumour Center Munich 1977-98.

BACKGROUND: Although survival in patients with thin melanomas (tumour thickness < or = 0.75 mm) is usually excellent, thin melanomas have the potential to metastasize. OBJECTIVES: To determine risk factors for the development of disease progression in patients with thin cutaneous melanomas. METHODS: A retrospective study was performed between 1977 and 1998 to identify risk factors for the development of disease progression in 2302 patients with cutaneous melanoma with tumour thickness < or = 0.75 mm, diagnosed and treated at the Department of Dermatology and Allergology, Ludwig-Maximilians University, Munich, Germany. The Kaplan-Meier method was used to estimate the influence of different clinical characteristics for the occurrence of first progression during 10 years of follow-up. RESULTS: An analysis of the data from 6298 patients with cutaneous melanoma identified 2302 patients (37%) who presented with cutaneous melanoma with a tumour thickness < or = 0.75 mm, without clinical signs of metastasis at initial diagnosis (clinical stage Ia). A small subgroup of our patients (77 of 2302) developed metastatic disease during the follow-up period. The estimated rate of occurrence of metastasis after 10 years of follow-up was 4.7%. The mean follow-up time was 62 months (median 46). Of these 77 patients, 16 experienced progression at the primary tumour site and 32 presented with regional lymph node metastases. Twenty-eight patients primarily developed systemic metastases (seven patients with and 20 without regional lymph node metastases, one patient with regional lymph node metastases and local recurrence). In one patient the primary site of metastatic disease was not reported. Clinical characteristics included age, sex of the patient and different subtypes of cutaneous melanoma: superficial spreading melanoma, nodular melanoma, acrolentiginous melanoma (ALM) and lentigo maligna melanoma (LMM). Male patients and patients with LMM or ALM were significantly over-represented (P = 0.02 and P = 0.002). In the group of 77 patients with thin melanomas (< or = 0.75 mm), local recurrence was over-represented as compared with those with melanomas > 0.75 mm. No difference in group was found for overall survival after the occurrence of lymph node metastasis as the first manifestation of disease progression. CONCLUSIONS: Thorough follow-up and skin examination is recommended for a subgroup of patients with thin tumours, which consists of male patients with LMM or ALM located in the head and neck region.

Adult↗
PubMed2002

Effect of antiretroviral triple combinations including the protease inhibitor nelfinavir in heavily pretreated children with HIV-1 infection.

BACKGROUND: In this retrospective study the effect of antiretroviral triple therapy including the protease-inhibitor nelfinavir (NFV) on CD4-cells and viral load (VL) in heavily pretreated HIV-infected children was evaluated. PATIENTS AND METHODS: 20 children (<18 years) were included. Median duration of antiretroviral pretreatment was 27 months (range, 7 65), median initial VL was 4.7 log subset 10 (3.2 6.1) and median relative CD4-cells was 17.5% (3 33). Patients were put on combinations with NFV because of treatment failure (increasing VL), intolerance to prior therapy with PIs or adherence problems with prior indinavir. Viral load (RT-PCR, detection limit 50 copies/ml) and CD4-cells were measured every 4-8 weeks. RESULTS: Median viral load decreased 1.2 log(10) (-1.3 2.5), 0.9 log(10) (-0.8 - 2.5) and 0.4 log(10) (-0.5 - 3.0) after 12, 24 and 36 weeks. The VL of 2 patients was below the detection limit (50 copies/ml) after 24 weeks. The relative CD4-cell count increased from a median of 17.5% to 22%, 23% and 25% after 12, 24 and 36 weeks, respectively. Side effects of NFV were usually mild. WHO grade 1 or 2 diarrhea occurred in 70% and moderate elevations of triglycerides in 40% of the patients. At 48 weeks 18/20 patients had to be switched to other combinations due to virological failure. CONCLUSIONS: In children with intensive prior antiretroviral therapy combination therapy including NFV lead to a modest short-term reduction of the VL and increase in CD4-cells. However, the long-term antiretroviral effect was poor.

Adolescent↗
PubMed2002

Decreased proliferation of human melanoma cell lines caused by antisense RNA against translation factor eIF-4A1.

Control of translation initiation was recognised as a critical checkpoint for cell proliferation and tumorigenesis. In human melanoma cells, we have previously reported consistent overexpression of translation initiation factor eIF-4A1. Here, we investigated by transfection of antisense constructs its significance for the control of melanoma cell growth. The tetracycline-inducible expression system was established in melanoma cells, and three fragments of the 5'-, central-, and 3'-portion of the eIF-4A1 cDNA were subcloned in antisense and in sense orientation after a tetracycline inducible promoter. Significant proliferation decrease was obtained after transient transfection and induction of antisense RNA directed against the 5'- and the central portion (up to 10%), whereas, no effects were seen after induction of the 3'-fragment and the sense controls. Cell clones stably transfected with the central antisense fragment revealed after doxycycline induction reduced expression of endogeneous eIF-4A1 mRNA correlated with decreased proliferation rates (up to 6%). These data demonstrate the applicability of antisense strategies against translation factors in melanoma cells. Translation initiation factor eIF-4A1 contributes to the control of melanoma cell proliferation and may be taken into consideration when scheduling new therapeutic approaches targeting the translational control.

Anti-Bacterial Agents↗
PubMed2002

Fibroblasts enhance the invasive capacity of melanoma cells in vitro.

In previous experiments we have shown an enhanced expression of matrix metalloproteinase-1 (MMP-1) in fibroblasts obtained from the border of invasive melanoma in comparison to fibroblasts more distant from the tumour. In the study reported here we sought to determine whether melanoma-derived soluble factors are responsible for the stimulation of MMP-1 expression in fibroblasts. By real-time PCR and enzyme-linked immunosorbent assays, we demonstrated that the stimulation of fibroblasts with melanoma cell conditioned medium led to an increased expression of MMP-1 mRNA as well as MMP-1 protein, whereas melanoma cells themselves did not produce detectable amounts of MMP-1 protein. Basic fibroblast growth factor (bFGF) was detected as an important factor responsible for the enhanced expression of MMP-1 by fibroblasts after stimulation with melanoma cell conditioned medium. In a three-dimensional in vitro invasion assay, we demonstrated that fibroblasts are essential for melanoma cell invasion into a collagen I matrix. These findings support the hypothesis that stromal fibroblasts assist the invasion of melanoma cells through the extracellular matrix by producing elevated amounts of proteolytic enzymes after interaction with soluble factors (e.g. bFGF).

Cells, Cultured↗
PubMed2002

Effect of antiretroviral combination therapies including efavirenz in heavily pretreated HIV-infected children.

BACKGROUND: In this retrospective study the effect of antiretroviral combination regimens including the non nucleoside reverse transcriptase inhibitor (NNRTI) efavirenz (EFV) on viral load (VL) and CD4-cell count in heavily pretreated HIV-infected children was investigated. DESIGN: The data of 15 children (< 16 years) were evaluated during a treatment period of at least 52 weeks. Patients received a median of 4 prior antiretroviral regimens and were changed to combinations with EFV because of renewed increasing VL. METHODS: Viral load (Amplicor, detection limit 50 copies/ml) and CD4-cells were measured every 4-8 weeks. RESULTS: The median reduction of the viral load for the total study population was 1.9 log10 (0.8 - 4.7), 2.3 log(10) (0.5 - 4.7) and 2.6 log(10) (0-4.7) after 12, 24 and 52 weeks, respectively. After 24 weeks 7/15 children and after 52 weeks 9/15 patients had reductions of the VL below the detection limit. The median increase of CD4-cells in the study population during the treatment period were 104 cells/microl (189-969), 220 cells/microl (170-831) and 321 cells/ml (162-574) after 12, 24 and 52 weeks, respectively. CONCLUSIONS: In children with intensive prior antiretroviral therapy and multiple therapeutic failures with PI-containing regimens, combination therapy including EFV resulted in an excellent antiretroviral efficacy. After 52 weeks 9/15 patients had persistent reductions of the VL below 50 copies/ml, although none of these children reached this level of viral suppression during their multiple prior protease inhibitor-containing regimens.

Adolescent↗
PubMed2002

[Kidney calculus episode in a supernumerary 3rd kidney].

Supernumerary kidney is a rare renal anomaly. As a distinct encapsulated parenchymatous mass, this free accessory organ has a separate blood supply and excretory duct system. We report on a patient who presented with an acute episode of abdominopelvic pain, secondary to hydronephrosis of a third kidney, situated in the pelvis behind the bladder. Modern diagnostic methods assisted in the conservative management of this well functioning third kidney.

Humans↗
PubMed2001

Modulation of HIV-1 enhancer activity and virus production by cAMP.

The effect of cAMP on the transcriptional activity of the HIV-1 long terminal repeat/enhancer was investigated and compared to the effect of cAMP on virus replication. In culture cAMP repressed virus replication in vivo using different cell types. Transient transfection studies with HIV-1 enhancer-derived luciferase reporter gene constructs identified the minimal DNA sequence mediating the negative regulatory effect of cAMP on HIV-1 transcription. A single nuclear factor kappaB element from the HIV-1 enhancer mediates the repressive effect on transcription. AP-2 is not involved in cAMP repression. Stable transfection of Jurkat T cells with the co-activators CREB binding protein (CBP) and p300 completely abolished the cAMP repressive effect, supporting the hypothesis that elevation of intracellular cAMP increases phosphorylation of CREB, which then competes with phosphorylated p65 and Ets-1 for limiting amounts of CBP/p300 thereby mediating the observed repressive effect on transcription. These findings suggest an important role of cAMP on HIV-1 transcription.

Binding Sites↗
PubMed2001

The Bax/Bcl-2 ratio determines the susceptibility of human melanoma cells to CD95/Fas-mediated apoptosis.

Defective cytochrome c release and the resulting loss of caspase-3 activation was recently shown to be essential for the susceptibility of human melanoma cells to CD95/Fas-induced apoptosis. Cytochrome c release from mitochondria is regulated by the relative amounts of apoptosis-promoting and apoptosis-inhibiting Bcl-2 proteins in the outer membrane of these organelles. The assignment of Bax/Bcl-2 ratios by quantitative Western blotting in 11 melanoma cell populations revealed a relation to the susceptibility to CD95-mediated apoptosis. We could show that a low Bax/Bcl-2 ratio was characteristic for resistant cells and a high Bax/Bcl-2 ratio was characteristic for sensitive cells. Low Bax expression was not a consequence of mutations in the p53 coding sequence. The Bax/Bcl-2 ratio was also in clear correlation with sensitivity to another cell death inducer, N-acetylsphingosine. Furthermore, Bcl-2 overexpression abolished apoptosis triggered by both apoptotic stimuli, confirming the critical role of the Bax/Bcl-2 ratio as a rheostat that determines the susceptibility to apoptosis in melanoma cells by regulating mitochondrial function. Interestingly, some chemotherapeutics lead to the activation of death pathways by CD95L upregulation, ceramide generation, direct activation of upstream caspases, or upregulation of proapoptotic genes. Taken together, these signals enter the apoptotic pathway upstream of mitochondria, resulting in activation of this central checkpoint. We therefore assumed that apoptosis deficiency of malignant melanoma can be circumvented by drugs directly influencing mitochondrial functions. For this purpose we used betulinic acid, a cytotoxic agent selective for melanoma, straightly perturbing mitochondrial functions. In fact, betulinic acid induced mitochondrial cytochrome c release and DNA fragmentation in both CD95-resistant and CD95-sensitive melanoma cell populations, independent of the Bax/Bcl-2 ratio.

Antineoplastic Agents, Phytogenic↗
PubMed2001

B lymphopoiesis is upregulated after orchiectomy and is correlated with estradiol but not testosterone serum levels in aged male rats.

Previous studies have shown that B lymphopoiesis is augmented after androgen withdrawal in male mice. As an analogy to the skeletal system, some effects of androgens on the proliferation of B cells may be mediated via aromatization into estrogens in vivo. The aim of the present study was to assess the effects of androgen withdrawal on B lymphopoiesis in bone marrow of aged male rats sequentially over a period of 9 months, and to correlate the flow-cytometric findings with changes in systemic levels of sex steroids. We first showed that androgen withdrawal is associated with enhanced B lymphopoiesis in bone marrow of 4-month-old male orchiectomized (ORX) rats, and that the changes in the bone marrow B cell compartment in ORX animals can be reversed by testosterone supplementation. In a subsequent, sequential experiment, we found that orchiectomy induced a sustained rise in Thy 1.1+/CD45R+ bone marrow cells committed for the B cell lineage that lasted for several months in 13-month-old aged rats. In a stepwise model of multiple regression analysis using estradiol, free and total testosterone as independent variables, estradiol was the strongest predictor of the percentage of B precursor cells in bone marrow in aged SHAM and ORX rats. Free and total testosterone did not correlate with B lymphopoiesis in aged SHAM rats. The current experiment has clearly shown that androgen withdrawal upregulates the number of B lineage cells over several months in rat bone marrow. Furthermore, our results provide evidence that estradiol may play an important role as a physiological suppressor of B lymphopoiesis in aged male rats.

Aging↗
PubMed2000

Resistance to CD95/Fas-induced and ceramide-mediated apoptosis of human melanoma cells is caused by a defective mitochondrial cytochrome c release.

Intracellular CD95/Fas-signaling pathways have not been investigated in melanoma yet. Two different CD95 receptor-induced apoptotic pathways are presently known in other cell types: (i) direct activation of caspase-8 and (ii) induction of ceramide-mediated mitochondrial activation, both leading to subsequent caspase-3 activation. In the present study, five of 11 melanoma cell populations were shown to release cytochrome c from mitochondria, which activates caspase-3 and finally results in DNA fragmentation upon treatment with the agonistic monoclonal antibody CH-11. In contrast, this apoptotic pathway was not activated in the remaining six melanoma cell populations. Interestingly, the susceptibility of melanoma cells to CD95L/FasL-triggered cell death was clearly correlated with N-acetylsphingosine-mediated apoptosis. Our results are in line with a defect upstream of mitochondrial cytochrome c release in resistant cells.

Adaptor Proteins, Signal Transducing↗
PubMed2000

[Prolonged peridural analgesia (PDA) for postoperative pain therapy after major urologic interventions. Experiences with 172 adult patients].

UNLABELLED: The benefits of epidural analgesia are well known, but it is not well understood which types of urologic surgery benefit most from epidural analgesia. In this study, the effects and side effects of prolonged epidural analgesia are prospectively examined and analysed on 172 adult patients in three different operation groups. An epidural infusion of local anaesthetic combined with an opioid and adrenaline was given for a period of 5-7 days. There was no difference between the groups with respect to the effectiveness of the analgesia and patients' perception of the treatment. Mobilization differed, as expected, between the groups, however even after the most major surgery (e. g. cystectomy with bladder substitution), mobilization was impressively unproblematic. Retarded return of regular intestinal function after the transperitoneal operation and partly after lumbotomy compared with the extraperitoneal operation depended on which operation was performed and the amount of analgesia given. The side effects such as sedation, nausea and pruritus were conditional partly on the opiate and partly on the intervention. Up to 11 % showed slight muscular weakness of the lower limbs as a specific side effect of the local anaesthetic. COMPLICATIONS: One patient died of cerebral hypoxia due to an initially undetected subdural catheter placement complicated by severe pre-existent carotid stenosis. In four patients, the epidural analgesia had to be stopped because of catheter migration. There was no clinical evidence of hematoma, abscess or permanent neurological damage. Epidural analgesia works well in terms of analgesia, mobilization and patient satisfaction, bearing in mind the potential side effects and complications. It can be recommended for lumbotomy and long transperitoneal operations however not for extraperitoneal interventions in the lower abdomen such as radical prostatectomy.

Adult↗
PubMed2000

Comparison of ritonavir plus saquinavir- and nelfinavir plus saquinavir-containing regimens as salvage therapy in children with human immunodeficiency type 1 infection.

BACKGROUND: In this retrospective study we compared the antiretroviral effect of regimens consisting of simultaneous administration of two protease inhibitors (PI) with at least one nucleoside reverse transcriptase inhibitor on plasma viral load (VL) and CD4 cell count in HIV-infected children intensively pretreated with nucleoside reverse transcriptase inhibitors and PIs. METHODS: Eleven HIV-infected children were changed to antiretroviral combination regimens including two PIs and followed for a median time of 24 weeks. Group A comprised six patients who were given ritonavir + saquinavir (SQV) and Group B consists of five patients who were changed to nelfinavir + SQV. Patients were treated with these combinations with 2 PIs because of treatment failure (increasing viral load) of prior PI therapy or clinical signs of disease progression. OUTCOME MEASURES: Serial determinations of plasma viral load (Amplicor, Roche) and CD4 cells were performed every 4 to 8 weeks. The detection limit of the Amplicor-reverse transcriptase-PCR assay was 50 copies/ml (1.7 log10). RESULTS: In Group A the median VL reduction was 1.1 log10 after 3 months and 1.4 log10 after 6 months. In Group B median VL decreased 0.1 and 0.2 log10 after 3 and 6 months. In both groups during the study period none of the patients reached undetectable VL. The relative changes of CD4 cells above baseline in Group A showed a median increase of 7% after 3 months and 23% after 6 months. In Group B after 3 months CD4 cells did not increase, and after 6 months the median relative increase was only 7%. Both combination therapies were well tolerated, not necessitating any drug interruption during study period. CONCLUSIONS: In children with intensive prior antiretroviral treatment, a salvage therapy including two PIs demonstrated antiretroviral efficacy in some patients. In this study the reduction of the VL as well as the increase of CD4 cells was more pronounced with ritonavir + SQV than with nelfinavir + SQV. With both combinations complete suppression of HIV replication was not achieved. Therefore the long term effect of these combinations may be limited by the emergence of resistant HIV strains.

Adolescent↗
PubMed2000

Ubiquitination of the human immunodeficiency virus type 1 env glycoprotein.

Expression of the human immunodeficiency virus type 1 (HIV-1) Env glycoprotein is stringently regulated in infected cells. The majority of the glycoprotein does not reach the cell surface but rather is retained in the endoplasmic reticulum or a cis-Golgi compartment and subsequently degraded. We here report that Env of various HIV-1 isolates is ubiquitinated at the extracellular domain of gp41 and that Env expression could be increased by lactacystin, a specific proteasome inhibitor, suggesting that the ubiquitin/proteasome system is involved in control of expression and degradation.

HIV Envelope Protein gp41↗