The B-chain of mistletoe lectin I efficiently stimulates calcium signaling in human Jurkat T-cells.

Mistletoe lectin I (ML I), a heterodimeric disulfide-linked type II ribosome inactivating protein, exhibits immunomodulatory potency in stimulating the cytokine release in vitro and in vivo. However, data concerning early activation events in T-cells induced by ML I and its A and B chain preceding cytokine secretion and the receptors involved are of limited availability. Here we show by flow cytometric measurements that human T-lymphoblastoid Jurkat cells express surface glycoprotein receptors for ML I. One of which is shown to be the CD2 antigen involved in a variety of T-cell signaling events. The lectin induces in Jurkat T-cells an increase of the cytosolic calcium concentration ([Ca(2+)](i)) consisting of both, the transient release of Ca(2+) from internal stores and a sustained influx of extracellular Ca(2+). Studies with isolated A- and B-chains provided evidence that the lectin-induced increase in [Ca(2+)](i) is mediated by ML IB. The ML I and ML IB stimulated cellular calcium responses are inhibited by saccharidic competitors. In transiently transfected E6.1 cells ML IB stimulated the expression of the luciferase reporter construct pNFAT-TA-Luc that is activated through the nuclear factor of activated T-cells (NFAT). The ML IB stimulated expression of the reporter luciferase (Luc) is completely inhibited by cyclosporin A (0.2 microM) and by FK 506 at 0.05 microM. Pretreatment of Jurkat E6.1 cells with 1-deoxymannojirimycin (dMJ), an inhibitor of cis-Golgi alpha-mannosidase I, strongly reduced cell binding of ML IB-FITC and the ML IB induced calcium response. Benzyl-alpha-GalNAc, an inhibitor of O-linked glycosylation, has slightly decreasing effects in ML IB-FITC binding and was without effects on the lectin stimulated increase in [Ca(2+)](i). Inhibition of the lectin induced calcium responses by cholera toxin and by inhibitors of protein kinases as well as the absence of calcium responses in CD3- and CD45- Jurkat T-cell clones suggest that ML IB has the potency to induce early T-cell activation events.

Docetaxel monotherapy in heavily pretreated metastatic breast cancer: a multicenter, community-based feasibility trial.

PURPOSE: To evaluate the efficacy and safety of docetaxel in heavily pretreated and anthracycline-resistant patients with metastatic breast cancer in an outpatient setting. PATIENTS AND METHODS: Between February 1996 and June 1998, 98 consecutive patients who had progressed during or relapsed following prior anthracycline-containing chemotherapy were enrolled into the trial. Docetaxel was administered at a dose of 100 mg/m2 by intravenous infusion every 3 weeks. The administration of colony-stimulating factors was at the discretion of the attending physician. Premedication with dexamethasone was mandatory for all patients. RESULTS: Of the 98 patients, 93 were evaluable for toxicity and response. Patients had received two palliative regimens (median, range 1-5) prior to docetaxel treatment. The most frequent toxicity observed was leukopenia grade III and IV (WHO grading system) which occurred in 47% of patients (grade IV only in 14%). Except for alopecia grade III (64% of patients), nonhematologic side effects grade III-IV were rare (1-7% of patients) and included nausea, stomatitis, diarrhea, peripheral neuropathy, fluid retention and pulmonary toxicities. There were no treatment-related deaths. Objective responses occurred in 40% of patients (CR 6%, PR 34%), and stable disease in 38% of patients. The median duration of response was 5.3 months (range 0.7-18.1 months) while the median survival was 15 months (range 2 36 months). CONCLUSION: Docetaxel is a highly active agent in patients with anthracycline-resistant metastatic breast cancer, even in heavily pretreated patients, with moderate toxicity.

Prognostic significance of the time of developing motor deficits before radiation therapy in metastatic spinal cord compression: one-year results of a prospective trial.

PURPOSE: To investigate prospectively the prognostic value of the time of developing motor deficits before radiation therapy (RT) for post-treatment functional outcome in metastatic spinal cord compression. METHODS AND MATERIALS: From November 1998 until October 1999, 57 patients were included. Two subgroups were formed according to the time of developing motor deficits before RT: 1-14 days (n = 29) and > 14 days (n = 28). Therapeutic effect on motor function was evaluated by an 8-point scale directly, 6, 12, and 24 weeks after RT. Patients with rapid deterioration of motor function within 48 h before RT (n = 14) were evaluated separately. RESULTS: Directly after RT, 26/28 patients (93%) of the group developing motor deficits > 14 days showed improvement of motor function, in comparison to 3/29 patients (10%) of the group 1-14 days (p < 0.001). Deterioration rates were 0% (> 14 days) and 45% (1-14 days). In patients with rapid deterioration of motor function within 48 h before RT, prognosis was poor (improvement 0%, no change 43%, deterioration 57%). Results were comparable 6, 12, and 24 weeks after RT. CONCLUSION: A slower development of motor deficits before RT predicts a better post-treatment functional outcome. In patients with rapid deterioration of motor function within 48 h before RT, prognosis was extraordinarily poor. These results support the findings of our preceding retrospective analysis.

Involvement of CD2 and CD3 in galectin-1 induced signaling in human Jurkat T-cells.

Galectin-1 (gal-1) a member of the mammalian beta-galactoside-binding proteins recognizes preferentially Galbeta1-4GlcNAc sequences of oligosaccharides associated with several cell surface glycoconjugates. In the present work, gal-1 has been identified to be a ligand for the CD3-complex as well as for CD2 as detected by affinity chromatography of Jurkat T-cell lysates on gal-1 agarose and by binding of the biotinylated lectin to CD3 and CD2 immunoprecipitates on blots. In CD45(+)Jurkat E6.1 cells, the lectin stimulates a sustained increase in the intracytoplasmic calcium concentration ([Ca(2+)](i)) consisting of both the release of calcium from intracellular stores and the calcium influx from the extracellular space. This effect of gal-1 on [Ca(2+)](i)is completely inhibited by lactose at 10 mM and was absent in CD45(-)Jurkat J45.01 cells. Preincubation of Jurkat E6.1 cells with cholera toxin or with the protein tyrosine kinase inhibitor herbimycin A reduced the gal-1 induced calcium response whereas the increase in [Ca(2+)](i)stimulated by CD2 or CD3 monoclonal antibodies (mAbs) was completely inhibited. Depolarization of E6.1 cells in a high-potassium buffer, a standard method to activate voltage-operated calcium channels, was without effect on [Ca(2+)](i). Membrane depolarization with gramicidin or by a high-potassium buffer was without effects on the lectin-mediated calcium release from intracellular stores but inhibited the gal-1 induced receptor-operated calcium influx. In Jurkat E6.1 cells the lectin stimulates the transient generation of inositol-1,4,5-trisphosphate and the tyrosine phosphorylation of phospholipase Cgamma1. The results suggest that the ligation of CD2 and CD3 by gal-1 induces early events in T-cell activation comparable with that elicited by CD2 or CD3 mAbs.

Metastatic spinal cord compression. Influence of time between onset of motoric deficits and start of irradiation on therapeutic effect.

BACKGROUND: In a retrospective analysis we investigated the prognostic significance of the interval between first appearance of motoric deficits and the beginning of radiation therapy (RT) with regard to posttreatment motoric function. MATERIAL AND METHODS: Data of more than 400 consecutive patients being irradiated at our department between 1994 and 1997 because of vertebral metastases were reviewed. Ninety-six patients fulfilled selection criteria including motoric deficits, no preceding surgical or radiotherapeutic treatment of the spine, minimum total dose of 24 Gy referred to spinal cord, and additional treatment with dexamethasone. Two subgroups with a similar number of patients for better comparability were formed according to the time of developing motoric deficits: 1 to 13 days (49 patients) and > or = 14 days (47 patients). Effect of irradiation on motoric function was evaluated 2 weeks and about 3 months after radiotherapy. Patients with severe deterioration of motoric function within 48 hours before radiation therapy (31 patients) were looked at separately. RESULTS: Two weeks after radiotherapy 42/47 patients (89%) developing motoric deficits > or = 14 days showed improvement of motoric function in comparison to 6/49 patients (12%) of the other group. Deterioration occurred in 1/47 patients (2%) of the first and in 24/49 patients (49%) of the latter group. In case of severe deterioration of motoric function within 48 hours before radiation therapy only 2/31 patients (6%) showed improvement, but 20/31 (65%) deterioration. About 3 months after radiotherapy comparable results were observed. Median survival time was 4 months. CONCLUSION: A slower development of motoric deficits before beginning of radiotherapy means a better therapeutic effect and a more favorable functional outcome after treatment. The prognosis is extraordinarily poor if severe deterioration of motoric function occurs within 48 hours before radiotherapy.

Effectiveness of hypofractionated radiotherapy in painful bone metastases. Two prospective studies with 1 x 4 Gy and 4 x 4 Gy.

BACKGROUND: Although effectiveness of fractionated radiotherapy for painful bone metastases is well documented, there are unanswered questions regarding the adequacy of low-dose short radiation schedules for long-term pain control which give maximum benefit in patients with a short life expectancy. PATIENTS AND METHODS: Two consecutive non-randomized prospective follow-up studies were performed at a single institution to analyze pain response and duration of response in patients with a variety of primary tumors. Included were only patients with symptomatic nonvertebral bone metastases and without impending pathologic fracture. Forty-five patients received 1 x 4 Gy to 50 different sites (group I) while 86 patients received 4 x 4 Gy to 96 sites (group II). Pain relief to irradiation was evaluated according to patient interviews using a 4-point categorical scale. Follow-up was performed 7 and 90 days after radiotherapy. RESULTS: Pain relief after 4 x 4 Gy was significantly superior to 1 x 4 Gy with pain control rates being 86.5% vs 48% at day 7 (after end of treatment) and 80% vs 55% at day 90, respectively. A subgroup analysis of patients treated with 4 x 4 Gy demonstrated a more favorable outcome for breast cancer patients in comparison to patients with other primaries concerning pain relief (96% vs 81%), pain control after 90 days (93% vs 72%), median time to pain progression (9 vs 3 months), and median overall survival (14 vs 5.5 months). CONCLUSIONS: In this study 4 x 4 Gy proved to be clearly superior to 1 x 4 Gy in relieving pain from symptomatic nonvertebral bone metastases without impending pathologic fracture. Even if radiotherapy with 1 single fraction seems to be applicable in specific cases doses higher than 4 Gy should be chosen. In breast cancer patients pain control seems to be better compared to other primaries.