Early cytological diagnosis of diffuse malignant mesothelioma of the peritoneum: a case report

Mesotheliomas are the most frequent primary malignant tumors of serosal cavities with a poor prognosis. A definitive and early diagnosis on effusion samples is important, because recent advances in therapy for patients with mesothelioma may result in an improved outcome if they are applied to stage I disease.We report a case of malignant peritoneal mesothelioma diagnosed repeatedly by cytology in ascites fluids 1.5 yr before the diagnosis was confirmed by biopsy histology. The cytological diagnoses were supported by immunocytochemistry, DNA-cytometry, and AgNOR-analysis. Routine cytology supported by three adjuvant methods enabled us to correctly establish the diagnosis. Our case suggests that a cytological diagnosis of malignant mesothelioma supported by adjuvant methods should not be rejected even if based on negative histological results.     

Resveratrol modulates DNA double-strand break repair pathways in an ATM/ATR-p53- and -Nbs1-dependent manner

Resveratrol (RV) inhibits tumour initiation, promotion and progression which has mainly been explained by its properties in cell cycle control and apoptosis induction. So far, ambiguous observations have been published regarding its influence on genomic stability. To study RV's effects on DNA double-strand break (DSB) repair, we applied the established enhanced green fluorescent protein (EGFP)- and I-SceI-based assay system on RV-treated lymphoblastoid cell lines (LCLs). We show that RV inhibits both, homologous recombination (HR) and non-homologous end joining (NHEJ) independently of its known growth and death regulatory functions. Using (i) the isogenic cell lines TK6 and WTK1, which differ in their p53 status, (ii) LCLs from patients with ataxia telangiectasia, (iii) shRNA-mediated p53 knockdown and (iv) chemical inhibition of ATM/ATR by caffeine, we established an ATM-p53-dependent pathway of HR inhibition by RV. Additional use of LCLs from Nijmegen breakage syndrome patients furthermore provided evidence for an ATM/ATR-Nbs1-dependent inhibition of microhomology-mediated NHEJ after RV treatment. We propose that activation of ATM and/or ATR is a central effect of RV. Repression of error-prone recombination subpathways could at least partially explain the chemopreventive effects of this natural plant constituent in animal cancer models.     

Chemosensitivity of solid tumor cells in vitro is related to activation of the CD95 system

We have identified the CD95 system as a key mediator of chemotherapy-induced apoptosis in leukemia and neuroblastoma cells. Here, we report that sensitivity of various solid tumor cell lines for drug-induced cell death corresponds to activation of the CD95 system. Upon drug treatment, strong induction of CD95 ligand (CD95-L) and caspase activity were found in chemosensitive tumor cells (Hodgkin, Ewing's sarcoma, colon carcinoma and small cell lung carcinoma) but not in tumor cells which responded poorly to drug treatment (breast carcinoma and renal cell carcinoma). Blockade of CD95 using F(ab′)₂ anti-CD95 antibody fragments markedly reduced drug-induced apoptosis, suggesting that drug-triggered apoptosis depended on CD95-L/receptor interaction. Moreover, drug treatment induced CD95 expression, thereby increasing sensitivity for CD95-induced apoptosis. Drug-induced apoptosis critically depended on activation of caspases (ICE/Ced-3-like proteases) since the broad-spectrum inhibitor of caspases zVAD-fmk strongly reduced drug-mediated apoptosis. The prototype substrate of caspases, poly(ADP-ribose) polymerase, was cleaved upon drug treatment, suggesting that CD95-L triggered autocrine/paracrine death via activation of caspases. Our data suggest that chemosensitivity of solid tumor cells depends on intact apoptosis pathways involving activation of the CD95 system and processing of caspases. Our findings may have important implications for new treatment approaches to increase sensitivity and to overcome resistance of solid tumors. Int. J. Cancer 76:105–114, 1998.© 1998 Wiley-Liss, Inc.     

Minimal requirements for the diagnosis,classification, and evaluation of the treatment of childhood acute lymphoblastic leukemia (ALL) in the “BFM family” cooperative group

Minimal requirements and their rationale for the diagnosis and the response to treatment in childhood acute lymphoblastic leukemia (ALL) were defined in the recently instituted “BFM-Family”-Group, in which the German, Austrian, Dutch, Italian, Belgian, French and Hungarian childhood leukemia study groups cooperate. ALL is defined as ≥ 25% lymphoblasts in the bone marrow; for confirmation of the diagnosis and classification the criteria of the French-American-British (FAB) criteria are retained. For determination of the extent of the disease at diagnosis or relapse the criteria by the Rome Workshop [1986] are recommended: An obligatory panel of monoclonal antibodies for immunophenotyping was defined, as well as criteria for precursor B-ALL and T-ALL. Cytogenetic studies may support the diagnosis and subtyping, and are essential to identify certain patients with a high risk of treatment failure (f.i. t(9;22), t(4;11)). The role of molecular genetics for the diagnosis and the characterization of leukemia and the value of its clinical application needs further elucidation. Relapse was defined as recurrence of evident leukemia in the blood, bone marrow (≥ 25% lymphoblasts) or at any other site (to be confirmed by histological examination). Bone marrow involvement combined with extramedullary relapse was defined as ≥ 5% lymphoblasts in the bone marrow. © 1992 Wiley-Liss, Inc.     

Concomitant anti-arrhythmic surgery, using irrigated cooled-tip radiofrequency ablation, to treat permanent atrial fibrillation in CABG patients: expansion of the indication?

Objectives: The effectiveness of a concomitant anti-arrhythmic surgical procedure in coronary artery bypass grafting (CABG) patients with permanent atrial fibrillation (AF) was evaluated. Methods: This prospective study included 36 CABG patients, who had a concomitant anti-arrhythmic procedure using irrigated cooled-tip radiofrequency ablation. Follow-up included a 24 h EKG and ultrasound examination at 3, 6, 12 months. Results: Mean (SD) age was 68.7 years (8.0), left atrial diameter 44.9 mm (6.7), preoperative duration of AF 67 months (73), left ventricular ejection fraction 54% (14), euroscore 5.5 (2.6), number of distal anastomoses 3.3 (1.2), aortic cross-clamp time 90 (19) min, extracorporeal bypass time 156 (38) min. Thirty-day mortality was 2.8% (1/36). Mean (SD) follow-up was 25.3 months (17.9). Cumulative survival rates (SE) at 12 and 24 months were 0.94 (0.04) and 0.90 (0.06). Cumulative postoperative sinus rhythm (SR) rates (SE) at 6 and 12 months were 0.60 (0.08) and 0.75 (0.08). Restored bi-atrial contraction occurred in 73% (19/26) of all SR patients. As a consequence coumadine was stopped, after the 6th postoperative month, in 76% (16/21) in this subset of patients, corresponding with 44% (16/36) of all study group patients. One patient experienced a sick sinus syndrome 12 months postoperatively, for which a DDD pacemaker was implanted. Three out of five patients with a preexistent VVI pacemaker regained a stable postoperative SR with bi-atrial contraction, obviating the need of any pacemaker support.     

Loss of caspase-8 expression does not correlate with MYCN amplification, aggressive disease, or prognosis in neuroblastoma

Inactivation of caspase-8 because of aberrant gene methylation has been associated with amplification of the MYCN oncogene and aggressive disease in neuroblastoma, suggesting that caspase-8 may function as tumor suppressor. However, the prognostic effect of caspase-8 in neuroblastoma has remained obscure. Therefore, we investigated caspase-8 expression and its correlation with established prognostic markers and survival outcome in a large cohort of neuroblastoma patients. Here, we report that loss of caspase-8 protein expression occurs in the majority (75%) of neuroblastoma and is not restricted to advanced disease stages. Surprisingly, no correlation was observed between caspase-8 expression and MYCN amplification. Similarly, ectopic expression of MYCN or antisense-mediated down-regulation of MYCN had no effect on caspase-8 expression in neuroblastoma cell lines. In addition, caspase-8 expression did not correlate with other variables of high-risk disease (e.g., 1p36 aberrations, disease stage, age at diagnosis, or tumor histology). Most importantly, loss of caspase-8 protein had no effect on event-free or overall survival in the overall study population or in distinct subgroups of patients. By revealing no correlation between caspase-8 expression and MYCN amplification or other established variables of aggressive disease, our findings in a large cohort of neuroblastoma patients show that inactivation of caspase-8 is not a characteristic feature of aggressive neuroblastoma. Thus, our study provides novel insight into the biology of this tumor, which may have important clinical implications.     

Targeting inhibitor of apoptosis proteins (IAPs) for diagnosis and treatment of human diseases

Since cell death by apoptosis plays a key role in the regulation of tissue homeostasis, any defect in this intrinsic death program may result in tumor formation. "Inhibitor of apoptosis proteins" (IAPs) block apoptosis at the core of the apoptotic machinery by inhibiting effector caspases. Aberrant expression and/or function of IAPs have been implied to be involved in the pathogenesis and progression of various human diseases including cancer, autoimmune disorders or neurodegeneration. Recent insights into the regulation of IAPs have provided the basis for various exciting discoveries aimed at modulating expression or dysfunction of IAPs. Thus, targeting IAPs, e.g. by antisense approaches, RNA interference or small molecules, may proof to be a novel strategy for the diagnosis and treatment of human diseases.     

Tumor necrosis factor-related apoptosis-inducing ligand-mediated proliferation of tumor cells with receptor-proximal apoptosis defects

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) might represent a future cytotoxic drug to treat cancer as it induces apoptosis in tumor cells without toxicity in animal trials. We recently described that in contrast to apoptosis, TRAIL mediates tumor cell survival and proliferation in certain tumor cells. Here we studied the effect of TRAIL on 18 cell lines and 53 primary leukemia cells and classified these tumor cells into four groups: TRAIL, anti-DR4 or anti-DR5 induced apoptosis in group A cells, whereas they had no effect on group 0 cells and mediated proliferation in group P cells. To our surprise, TRAIL induced simultaneous apoptosis and proliferation in group AP cells. More than 20% of all cells tested belonged to group P and showed TRAIL-mediated proliferation even in the presence of certain cytotoxic drugs but not inhibitors of nuclear factor-kappaB. Transfection with B-cell leukemia/lymphoma protein 2 transformed group A cells into group 0 cells, whereas transfection with Fas-associated polypeptide with death domain (FADD)-like interleukin-1-converting enzyme-inhibitory protein (FLIP) transformed them into group AP cells. Loss of caspase-8 or transfection of dominant-negative FADD transformed group A cells into group P cells. Taken together, our data suggest that proliferation is a frequent effect of TRAIL on tumor cells, which is related to receptor-proximal apoptosis defects at the level of the death-inducing signaling complex and should be prevented during antitumor therapy with TRAIL.     

Sensitization for anticancer drug-induced apoptosis by betulinic Acid

We previously described that betulinic acid (BetA), a naturally occurring pentacyclic triterpenoid, induces apoptosis in tumor cells through the mitochondrial pathway. Here, for the first time, we provide evidence that BetA cooperated with anticancer drugs to induce apoptosis and to inhibit clonogenic survival of tumor cells. Combined treatment with BetA and anticancer drugs acted in concert to induce loss of mitochondrial membrane potential and the release of cytochrome c and Smac from mitochondria, resulting in activation of caspases and apoptosis. Overexpression of Bcl-2, which blocked mitochondrial perturbations, also inhibited the cooperative effect of BetA and anticancer drugs, indicating that cooperative interaction involved the mitochondrial pathway. Notably, cooperation of BetA and anticancer drugs was found for various cytotoxic compounds with different modes of action (e.g., doxorubicin, cisplatin, Taxol, VP16, or actino-mycin D). Importantly, BetA and anticancer drugs cooperated to induce apoptosis in different tumor cell lines, including p53 mutant cells, and also in primary tumor cells, but not in human fibroblasts indicating some tumor specificity. These findings indicate that using BetA as sensitizer in chemotherapy-based combination regimens may be a novel strategy to enhance the efficacy of anticancer therapy, which warrants further investigation.