The heterodimerization domains of MLL-FYRN and FYRC--are potential target structures in t(4;11) leukemia.

The chromosomal translocation t(4;11)(q21;q23) is a frequent genetic aberration of the mixed lineage leukemia (MLL) gene, predominantly associated with high-risk acute lymphoblastic leukemia (ALL) in pediatric patients. Previous studies demonstrated that mice transplanted with hematopoietic cells expressing the AF4-MLL fusion protein develop proB ALL. The AF4-MLL oncoprotein becomes activated by Taspase1-mediated hydrolysis, which subsequently leads to a heterodimer of the cleavage products AF4-MLL·N and MLL·C. This protein-protein interaction is due to the FYRN and FYRC interaction domains present in both protein fragments. Heterodimerization subsequently induces high-molecular-weight protein complex formation that is protected against SIAH1/2-mediated polyubiquitinylation. Here, we attempted to selectively block this initial heterodimerization step, aiming to prevent the oncogenic activation of the AF4-MLL multiprotein complex. The minimal interaction interface was experimentally defined first in a bacterial two-hybrid system, and then in mammalian cells by using a biosensor assay. Expression of the FYRC domain, or smaller portions thereof, resulted in the inhibition of heterodimer formation, and blocked AF4-MLL multiprotein complex formation with subsequent destruction of the AF4-MLL oncoprotein. Thus, it is in principle possible to specifically target the AF4-MLL protein. This knowledge can now be exploited to design inhibitory decoys in order to destroy the AF4-MLL oncoprotein.

Response to topotecan of symptomatic brain metastases of small-cell lung cancer also after whole-brain irradiation. a multicentre phase II study.

The purpose of this multicentre phase II study was to evaluate the efficacy and toxicity of topotecan in pretreated patients with small-cell lung cancer (SCLC) who relapsed with symptomatic brain metastases. 30 patients with a median age of 62 years were entered into the study. 22 patients received the initially planned dose of 1.5 mg/m(2) topotecan as a 30-min intravenous (i.v.) infusion for 5 consecutive days every 3 weeks. Due to the observed thrombocytopenia, the dose was reduced to 1.25 mg/m(2) in the last 8 patients. All 30 patients were pretreated with chemotherapy: 14 with one and 16 with at least two protocols. 8 patients had prior whole-brain iradiation (WBI): 7 in the prophylactic and 1 in the palliative setting. Concomitant systemic metastases were recorded in 24 patients at the time of brain relapse. Cerebral metastases responded in 33% of patients (10/30; three complete responses (CR) and seven partial responses (PR)). Noteworthy is the fact that response was achieved in 4 of 8 patients pretreated by WBI (3 in prophylactic and 1 in palliative setting). The systemic response rate was 29% (7/24). Median time to progression was 3.1 months (range 0.25-14.2+ months), median survival from the beginning of this study was 3.6 months (range 0.25-14.2+ months). Therapy was generally well tolerated, with myelotoxicity being the most common adverse event. Grade 3 leucocytopenia according to the Common Toxicity Criteria (CTC) occurred in 28% (23/83) of the courses and grade 4 in 22% (18/83). Grade 3 thrombocytopenia was observed in 17% of the courses (14/83) and grade 4 in 11% (9/83). 17% of patients (5/30) had a documented grade 3 infection. These results using topotecan are promising in heavily pretreated patients with SCLC brain metastases and merit further evaluation.

Neuropathy under chemotherapy.

Neuropathy is a dose-limiting side effect for a number of effective chemotherapeutic agents. A better understanding of effective mechanisms will lead to novel treatment strategies that will protect neurons without decreasing therapeutic efficacy. The assessment of the efficacy and neurotoxicity of various chemotherapeutic agents is vital, for a determination of the maximum allowable dose. The introduction of chemotherapy in the 50s and 60s of the twentieth century has resulted in the development of curative therapeutic interventions for patients with several types of solid tumours and hemopoietic neoplasms. The important obstacles encountered in the use of chemotherapy have been the toxicity to the normal tissue. During the past 8 years there has come about a new level of understanding of the mechanisms through which chemotherapeutic agents work. This has opened the door to new paradigms of treatment in which molecular, genetic, and biologic therapy can be used together to increase the sensitivity of abnormal cells to treatment, and to protect the normal tissues of the body from therapy-induced side effects. The implementation of new strategies could change the way therapy is delivered over the next few years and improve the outcome especially in patients with neoplasms that are currently resistant to conventional dose therapy.

Further evidence for oxidant-induced vascular endothelial growth factor up-regulation in the bronchoalveolar lavage fluid of lung cancer patients undergoing radio-chemotherapy.

BACKGROUND: Vascular endothelial growth factor (VEGF) is a potent inducer of physiological and neoplastic blood vessel growth. Moreover, in vitro studies have demonstrated that VEGF can be up-regulated by conditions associated with the generation of free radicals and reactive oxygen species. In a previous study we reported on strongly increased VEGF concentrations in the bronchoalveolar lavage fluid (BALF) of patients with lung cancer under therapy. In this study we aimed to reveal whether this increase was due to the therapy-associated intrapulmonary oxidative burden. PATIENTS AND METHODS: A total of 103 BALF samples from 94 patients with lung cancer (82 patients with non-small-cell lung cancer, 12 patients with small-cell lung cancer) were studied at different times before, during or after cancer treatment. VEGF levels in the lavage fluid and ratios of oxidised methionine in proteins of epithelial lining fluid (ELF) were determined. RESULTS: As reported previously, strongly increased VEGF levels in the ELF were observed in patients undergoing chemotherapy when radiotherapy had been administered before. Increased levels of oxidised methionine indicated that these patients suffered from severe pulmonary oxidative stress that was significantly less in patients undergoing only chemotherapy. Similarly, VEGF concentrations in the ELF were significantly elevated in cancer patients at the time of diagnosis, but the oxidised methionine levels did not reveal significant oxidant/antioxidant imbalances in these patients. CONCLUSION: Systemic chemotherapy is associated with oxidative stress in vivo, which is more pronounced if patients are additionally treated with radiation. VEGF levels in the ELF are increased by this condition as well as by the activity of the tumour itself.

Detection of microsatellite alterations in the DNA isolated from tumor cells and from plasma DNA of patients with lung cancer.

In this paper, we show that the same panel of three microsatellite markers is useful for the detection of alterations in the DNA of tumor cells and plasma from patients diagnosed with SCLC and NSCLC. In 31% of the SCLC patients, we detected a microsatellite alteration(s) or LOH in at least one locus. In the group of patients diagnosed with NSCLC, a microsatellite alteration or LOH was detected in at least one locus in 33% of the patients. In all but 2 patients, the identical alteration observed in the DNA from tumor cells was also detected in the DNA isolated from blood plasma. This work confirms the results described by other groups and it extends the diagnostic possibilities of finding tumor cell-specific DNA alterations also in the DNA freely circulating in plasma and serum of patients with cancer.

Increased levels of vascular endothelial growth factor in bronchoalveolar lavage of patients with bronchial carcinoma effect of tumour activity and oxidative stress due to radio-chemotherapy?

BACKGROUND: Vascular endothelial growth factor (VEGF) plays a crucial role in physiological and neoplastic angiogenesis. Moreover, VEGF has been found to be upregulated by conditions associated with the generation of free radicals and reactive oxygen intermediates. In patients with cancer, studies to evaluate VEGF as a measure of tumour activity were carried out. We tested the hypothesis that VEGF is additionally affected by oxidative stress due to anticancer therapy. Moreover, the suitability of epidermal growth factor (EGF) to estimate tumour activity was studied. PATIENTS AND METHODS: 60 patients with non-small cell lung cancer (NSCLC) covering different therapy progress and modalities underwent bronchoalveolar lavage. VEGF-, EGF-, albumin- and total protein-concentrations in bronchoalveolar lavage fluid (BALF) and VEGF-levels in blood plasma were studied. RESULTS: BALF VEGF-levels were increased in patients with advanced NSCLC before and in anticancer therapy. In patients who had received radiotherapy to the lung prior to chemotherapy, VEGF concentrations were noticeably higher than under sole chemotherapy. Pulmonary endothelial hyperpermeability was found in patients with recently diagnosed tumours and patients undergoing anti-cancer therapy. Evaluation of EGF-levels in BALF revealed no significant influence of tumour activity or cancer therapy on this parameter. CONCLUSION: BALF-levels of VEGF are affected by tumour activity and oxidative stress due to anticancer therapy.

Oxidant-induced lung injury in anticancer therapy.

Lung injury is one of the most frequent side effects in anticancer therapy. Especially simultaneous application of high doses of ionising radiation and radiosensitising cytotoxic drugs is considered to cause deleterious pneumonitis and pulmonary fibrosis. Growing evidence indicates that reactive oxygen species (ROS) play a key role in the development of these disorders. They are capable of causing cell component alterations and changing cellular protein expression. Observing these disease mechanisms reveals an impressive self-amplifying cascade of secondary ROS generation. Through intricate interactions between cells, cytokines and growth factors, fibroblasts are activated and thus pulmonary matrix content is massively increased. - As clinical appearance is uniform and unspecific, an early, reliable diagnosis of therapy-associated lung damage is not possible so far. However, improving this situation could enable us to take advantage of new multimodal therapeutic facilities. This review discusses mechanisms of ROS generation during radio-chemotherapy in the lung, antioxidant defense strategies and responses to oxidants, thereby assessing current diagnostic tools.

Comparison of three tropisetron-containing antiemetic regimens in the prophylaxis of acute and delayed chemotherapy-induced emesis and nausea.

There is still controversy as to what constitutes the optimal therapy for acute and delayed chemotherapy-induced emesis and nausea. We conducted a three-armed randomized multi-centre study in 193 chemotherapy-naive patients receiving highly emetogenic chemotherapy inducing both acute and delayed symptoms (cisplatin > or = 50 mg/m2, carboplatin > or = 300 mg/m2, cyclophosphamide > or = 750 mg/m2, ifosfamide > or = 1.5 g/m2 on day 1). Group A: 1 x 5 mg tropisetron i.v. on day 1 + 2, then 10 mg p.o. (oral dose now recommended: 5 mg); group B: tropisetron as for A+dexamethasone, 20 mg i.v., on days 1 + 2, then 4 mg i.v./p.o.; group C: tropisetron as for A+metoclopramide, 20 mg i.v. +2 x 10 mg p.o. on day 1, then 3 x 10 mg p.o. Treatment was continued for at least 2 days after the end of chemotherapy. Tropisetron+dexamethasone was significantly superior to tropisetron alone both for acute (P = 0.0064) and delayed (P = 0.0053) emesis. Complete control of acute and delayed emesis (nausea) was achieved in 80% (75%) and 53% (46%) in group A, 97% (90%) and 80% (58%) in group B, and 86% (80%) and 49% (45%) in group C. Patients completely asymptomatic during the whole cycle accounted for 26% of those in group A, 49% in group B and 28% in group C. The most frequent adverse events were constipation (16.6%), headache (7.3%) and tiredness (7.3%). Once-daily tropisetron+dexamethasone over several days is well tolerated and is a simple means of achieving further significant improvement in the efficacy of tropisetron against acute and delayed symptoms.