Apoptotic response to homoharringtonine in human wt p53 leukemic cells is independent of reactive oxygen species generation and implicates Bax translocation, mitochondrial cytochrome c release and caspase activation

In the present study, we investigated the in vitro apoptotic response of leukemic cells to the cellular stress induced by homoharringtonine (HHT), a plant alkaloid with antileukemic activity which is currently being tested for treatment of acute and chronic leukemias. A comparison of leukemic cell lines with different p53 gene status revealed a considerably higher sensitivity to HHT-induced apoptosis in the cells with a wt p53, and apoptotic events in wt p53 leukemia cells (MOLT-3 cell line) were studied in more detail. To this end, we examined components of apoptotic cascades including Bax expression and its intracellular localization, changes of mitochondrial membrane potential (MMP), reactive oxygen species (ROS) levels, cytochrome c release from mitochondria and activation of caspases. Bax protein levels did not increase despite an up-regulation of bax at mRNA level. However, Bax translocation from cytosol towards mitochondria was observed. In addition, we observed a release of cytochrome c from the mitochondria, and the localization changes of both Bax and cytochrome c were found already at the early, annexin V-negative stage of HHT-induced apoptosis. HHT-treated MOLT-3 cells revealed loss of MMP as well as activation of caspases demonstrated by DEVD-, IETD- and LEHD-tetrapeptide cleavage activity in the cell lysates. ROS levels only slightly increased in HHT-treated cells and antioxidants did not prevent apoptosis and MMP changes. Therefore, wt p53 leukemic cells respond to HHT-specific cellular stress by induction of ROS-independent apoptotic pathway characterized by translocation of Bax, mitochondrial cytochrome c release and activation of caspases.

Decreased generation of anti-tumor immunity after intrasplenic immunization

The localization of antigen and the nature of the host antigen-presenting cells (APC) that present it to T cells are two major determinants of antigen immunogenicity. While lymph nodes appear to be the major site for T cell priming, recently the spleen was shown to provide an optimal microenvironment for direct CD8+ cytotoxic T cell (CTL) priming by tumor cells even in the absence of known costimulatory molecules on tumor cells. We analyzed whether the splenic microenvironment would support T cell priming also when host APC are involved (cross-priming) which is probably the major pathway during the generation of anti-tumor immunity. We performed immunization/challenge experiments using different tumor cells (B7.1+, B7.1- and/or beta-gal+, beta-gal-) known to induce CTL to a variable extent either exclusively by cross-priming (B7-) or at least partially by direct priming (B7+). Our results demonstrate that tumor take in the spleen required much less cells than at a subcutaneous injection site. Additionally, intrasplenic immunization was invariably ineffective compared to subcutaneous immunization. We further showed that B cells were not responsible for the inefficient intrasplenic immunization. Therefore delivering the tumor cell antigens inside the spleen by intrasplenic immunization did not improve but rather decreased the efficacy of tumor cell vaccines.

Constitutive NF-kappaB maintains high expression of a characteristic gene network, including CD40, CD86, and a set of antiapoptotic genes in Hodgkin/Reed-Sternberg cells

Constitutively activated nuclear factor (NF)-kappaB is observed in a variety of neoplastic diseases and is a hallmark of the malignant Hodgkin and Reed-Sternberg cells (H/RS) in Hodgkin lymphoma. Given the distinctive role of constitutive NF-kappaB for H/RS cell viability, NF-kappaB-dependent target genes were searched for by using adenoviral expression of the super-repressor IkappaBDeltaN. A surprisingly small but characteristic set of genes, including the cell-cycle regulatory protein cyclin D2, the antiapoptotic proteins Bfl-1/A1, c-IAP2, TRAF1, and Bcl-x(L), and the cell surface receptors CD86 and CD40 were identified. Thus, constitutive NF-kappaB activity maintains expression of a network of genes, which are known for frequent, marker-like expression in primary or cultured H/RS cells. Intriguingly, CD40, which is able to activate CD86 or Bcl-x(L) via NF-kappaB, is itself transcriptionally regulated by NF-kappaB through a promoter proximal binding site. NF-kappaB inhibition resulted in massive spontaneous and p53-independent apoptosis, which could be rescued by ectopic expression of Bcl-x(L), underscoring its dominant role in survival of H/RS cells. Hence, NF-kappaB controls a signaling network in H/RS cells, which promotes tumor cell growth and confers resistance to apoptosis.

Analysis of p53/BAX/p16(ink4a/CDKN2) in esophageal squamous cell carcinoma: high BAX and p16(ink4a/CDKN2) identifies patients with good prognosis

PURPOSE

We have previously shown that loss of BAX expression is a negative prognostic factor in metastatic colorectal cancer. In the present study, we addressed the prognostic relevance of BAX and its upstream regulator p53 in squamous cell carcinoma (SCC) of the esophagus. Analysis of p16(ink4a/CDKN2) was included because p16(ink4a/CDKN2) and p53 were shown previously to cooperate during induction of cell cycle arrest and apoptosis.

PATIENTS AND METHODS

Retrospective analysis of 53 patients with curative intended R0 resection of esophageal SCC was done. Protein expression of BAX, p53, and p16(ink4a/CDKN2) was investigated by immunohistochemistry. In addition, tumor DNA was screened for BAX frameshift mutations by fragment length analysis and for p53 mutations by single-strand conformation polymorphism-polymerase chain reaction.

RESULTS

Overall median survival was 13.7 months. Patients with high BAX protein expression had a median survival of 19.5 months versus 8.0 months with low BAX expression (P <.005). High p16(ink4a/CDKN2) protein expression was associated with a median survival of 23.8 months versus 9.7 months with low p16(ink4a/CDKN2) (P =.011). The best survival (median, 45.8 months) was seen in a subgroup of 12 patients whose tumors bore the combination of both favorite phenotypes (ie, high BAX and high p16(ink4a/CDKN2) protein expression).

CONCLUSION

In this retrospective investigation, the combined analysis of BAX and p16(ink4a/CDKN2) shows subgroups in SCC of the esophagus with favorable (p16(ink4a/CDKN2)/BAX high expressing) or poor prognosis (loss of p16(ink4a/CDKN2)/loss of BAX). We suggest that such a multimarker analysis of apoptosis pathways could be useful for individualization of therapeutic strategies in the future, and suggest prospective studies to confirm these results.

Infectious complications after high-dose chemotherapy and autologous stem cell transplantation: comparison between patients with lymphoma or multiple myeloma and patients with solid tumors

From November 1994 to May 1998, 117 patients (66 with solid tumor, 36 with lymphoma, 14 with multiple myeloma, one with acute leukemia) underwent 178 cycles of high-dose chemotherapy and autologous stem cell transplantation (ASCT) at our institution. We retrospectively analyzed the infectious complications that occurred after ASCT. Median duration of neutropenia (granulocyte count <0.5 x 10(9)/l ) was 8 days, the overall incidence of fever requiring antimicrobial treatment was 63%. 35.4% of patients had fever of unknown orign (FUO), whereas primary bacteremia occurred in 21.3%, pneumonia in 3.4% and severe skin infection in 1.1% of patients. Invasive fungal infections occurred in three, and enterocolitis in one patient. Infection was fatal in three patients (2.6%), in each case due to septic shock. The most frequently isolated pathogens were Gram-positive cocci. Median time to defervescence with antimicrobial therapy was 4 days (6 days in patients with bacteremia or other severe infection, and 3 days in patients with FUO). First-line antimicrobial therapy was successful in 65% of patients with FUO and 30.6% of patients with documented infections. With respect to the incidence, type and clinical course of infection, no significant differences between patients with lymphoma or multiple myeloma and those with solid tumors were detected.

Activation of caspase-8 in drug-induced apoptosis of B-lymphoid cells is independent of CD95/Fas receptor-ligand interaction and occurs downstream of caspase-3

The activation of caspase-8, a crucial upstream mediator of death receptor signaling, was investigated in epirubicin- and Taxol-induced apoptosis of B-lymphoma cells. This study was performed because the CD95/Fas receptor-ligand interaction, recruitment of the Fas-associated death domain (FADD) adaptor protein, and subsequent activation of procaspase-8 have been implicated in the execution of drug-induced apoptosis in other cell types. Indeed, active caspase-8 was readily detected after treatment of mature and immature B-lymphoid cells with epirubicin or Taxol. However, neither constitutive nor drug-induced expression of the CD95/Fas ligand was detectable in B-lymphoma cells. Furthermore, overexpression of a dominant-negative FADD mutant (FADDdn) did not block caspase-8 processing and subsequent DNA fragmentation, indicating that drug-induced caspase-8 activation was mediated by a CD95/Fas-independent mechanism. Instead, caspase-8 cleavage was slightly preceded by activation of caspase-3, suggesting that drug-induced caspase-8 activation in B-lymphoma cells is a downstream event mediated by other caspases. This assumption was confirmed in 2 experimental systems-zDEVD-fmk, a cell-permeable inhibitor of caspase-3-like activity, blocked drug-induced caspase-8 cleavage, and depletion of caspase-3 from cell extracts impaired caspase-8 cleavage after in vitro activation with dATP and cytochrome c. Thus, these data indicate that drug-induced caspase-8 activation in B-lymphoma cells is independent of death receptor signaling and is mediated by postmitochondrial caspase-3 activation.

Four patients with AL amyloidosis treated with high-dose chemotherapy and autologous stem cell transplantation

Four patients with AL amyloidosis underwent high-dose chemotherapy and autologous stem cell transplantation at our institutions. Here, we report the clinical courses and outcomes in these patients. Two patients with multi-organ amyloid deposits including cardiac involvement died within 12 days after high-dose chemotherapy. However, in the other two patients, one of whom was suffering from amyloid-related cardiac failure, a significant improvement of organ function was achieved.

Anatomical variations in the internal jugular veins of cancer patients affecting central venous access. Anatomical variation of the internal jugular vein

PURPOSE

Establishing a reliable central venous access is an important procedure in clinical haematology and oncology. The purpose of this study was to determine how anatomical variations in the internal jugular vein (IJV) and its position in relation to the common carotid artery (CCA) in cancer patients affects external landmark puncture.

PATIENTS AND METHODS

In 113 patients with haematological or oncological diseases we examined sonographically potential target regions for placement of a central catheter via the IJV.

RESULTS

36% of our patients showed anatomical variations in the IJV and surrounding tissue.

CONCLUSIONS

External landmark puncture may be difficult in a considerable number of patients since the IJV might not be situated in the presumed location anteriorly or laterally to the CCA, or a normal lumen may not be present in approximately 1/3 of cancer patients. This study supports the use of ultrasound-guided techniques for central venous catheters particularly in haematological and oncological patients.

Bax expression in benign and malignant thyroid tumours: Dysregulation of wild-type P53 is associated with a high Bax and P21 expression in thyroid carcinoma

The purpose of our study was to determine the expression of the pro-apoptotic BAX protein in relation to the mutational status of BAX and p53 (as transcriptional activator of the BAX gene) in benign and malignant thyroid tissue. In 47 patients with thyroid tumours (14 follicular and 3 papillary carcinomas, 14 adenomas and 16 goitres), the DNA was screened for mutations of BAX (exon 1-6) and p53 (exon 5-8) by single-strand conformation polymorphism polymerase chain reaction (SSCP-PCR). Furthermore, the protein expression of BAX, p53 and p21 (which is also increased transcriptionally by p53) was investigated by immunohistochemistry. Surprisingly, we observed elevated BAX levels in patients with thyroid carcinomas compared with patients with adenomas (unpaired t-test: p<0.05) or with goitres (p<0.02). This is in clear contrast to other carcinomas where BAX is frequently inactivated which correlates to a poor prognosis (Sturm et al. J. Clin. Oncol. 1999;17:1364-74.). There were no significant differences of the BAX levels between goitres or the adenomas. In the SSCP-PCR analysis, no BAX mutations were detectable. P53 mutation analysis by SSCP-PCR did not reveal any functional p53 mutations in the patients with carcinomas, adenomas or goitres. Nevertheless, patients with carcinomas showed an overexpression (preferentially cytoplasmic) of p53 protein compared with patients with benign tumours (p<0.05). The absence of p53 mutations suggests that the overexpressed p53 is wild type. This is in line with the expression profile of BAX and p21, which showed a higher protein expression in these p53 positive tumours (p<0.05 in the carcinomas compared with the non-malignant lesions). Consequently, the overexpressed p53 might be a correlate for dysregulation without loss of function. This, in turn, might be a reason for the good outcome of some patients with thyroid cancer.

Granulocyte/macrophage-colony-stimulating-factor plus interleukin-2 plus interferon alpha in the treatment of metastatic renal cell carcinoma: a pilot study

Granulocyte/macrophage-colony-stimulating factor (GM-CSF) plays a central role in the differentiation and function of dendritic cells, which are crucial for the elicitation of MHC-restricted T cell responses. Preclinical and the first clinical data provide a rationale for the application of GM-CSF in immunotherapy of cancer. Ten patients with renal cell carcinoma stage IV (Holland/ Robson) were treated in this pilot study. Therapy was started with GM-CSF alone (2 weeks). Interleukin (IL-2) and interferon alpha (IFNalpha) were added sequentially (3 weeks GM-CSF plus IL-2 or IFNalpha, 3 weeks GM-CSF plus IL-2 plus IFNalpha). Therapy was performed on an outpatient basis. The cytokine regimen was evaluated for toxicity, clinical response and immunomodulatory effects [fluorescence-activated cell sorting analysis of peripheral blood mononuclear cells (PBMC), mixed-lymphocyte reaction and cytotoxicity of PBMC]. GM-CSF treatment caused a significant increase in the number of PBMC expressing costimulatory molecules. Addition of IL-2 and IFNalpha led to an increase in CD3 , CD4+, CD8+ and CD56+ PBMC in week 9. In an autologous mixed-lymphocyte reaction a 2.1-fold increase in T cell proliferation was observed after 2 weeks of GM-CSF treatment, and cytotoxicity assays showed changes in natural-killer-(NK)- and non-NK-mediated cytotoxicity in some patients. Two patients achieved partial remission, one patient had a mixed response. The toxicity of the regimen was mild to moderate with fever, flu-like symptoms and nausea being observed in most patients. Severe organ toxicity was not observed. We conclude that GM-CSF might be useful for immunotherapy of renal cell carcinoma, especially in combination with T-cell-active cytokines. Further studies are warranted.

Apoptosis: implications of basic research for clinical oncology

Recent studies have indicated a role for apoptosis in a variety of human diseases. Suppression of apoptosis contributes to carcinogenesis by several mechanisms, including facilitating the accumulation of gene mutations, permitting growth-factor-independent cell survival, promoting resistance to immune-based cytotoxicity, and allowing bypassing of cell-cycle checkpoints, which would normally induce apoptosis. Defects in apoptotic mechanisms also play an important part in resistance to chemotherapy and radiation. The core machinery of the cell death pathway can be reduced to a few critical types of proteins, which are well conserved across animal evolution. This review gives an update on the key players involved in apoptosis as well as an overview of the involvement of apoptosis in disease, and novel diagnostic and therapeutic options derived from the extensive basic research on this topic carried out over the last decade.

Anti-CD20- and B-cell receptor-mediated apoptosis: evidence for shared intracellular signaling pathways

Clinical administration of the anti-CD20 antibody IDEC-C2B8 can induce remission of low-grade B-cell lymphoma. Whereas it has been suggested that the main mechanisms of action are complement-mediated and antibody-dependent cell-mediated cytotoxicity, we demonstrate that monoclonal antibody IDEC-C2B8 is a strong inducer of apoptosis in CD20-positive B-cell lymphoma cell lines reflecting different stages of lymphomagenesis. Thus, CD20-dependent apoptosis was inducible in human surface IgM-positive Burkitt's lymphoma cell lines as well as in more mature surface IgM-negative B-cell lymphoma cell lines carrying the t(14;18) translocation. Furthermore, in Burkitt's lymphoma cell lines, we observed a striking correlation between anti-CD20- and B-cell receptor-mediated apoptosis with regard to sensitivity toward the apoptotic stimuli and the execution of the apoptotic pathway. Thus, induction of anti-CD20- or B-cell receptor-mediated apoptosis involved rapid up-regulation of the proapoptotic protein Bax. In addition, we show similar changes in the mRNA expression level of two early response genes, c-myc and Berg36, as well as activation of the mitogen-activated protein kinase family members p44 (extracellular signal-regulated kinase 1) and p42 (extracellular signal-regulated kinase 2) and activation of activator protein 1 (AP-1) DNA binding activity. These data support our hypothesis that both pathways are mediated in part by the same signal-transducing molecules. These results might help explain the resistance and regression of lymphomas to IDEC-C2B8 and give new insights in the signaling cascade after CD20 ligation.

Salvage therapy for relapsed mediastinal B-cell lymphoma with allogeneic HLA-identical related donor bone marrow transplantation, donor lymphocyte infusion and IDEC-C2B8

Primary B-cell lymphoma of the mediastinum is an aggressive non-Hodgkin's lymphoma with distinct clinicopathologic features. Response rates are between 60-80% following intensive chemotherapy regimens. Poor responders or patients with an early relapse usually do not achieve a prolonged second remission with conventional salvage therapy protocols and therefore qualify for intensive or experimental approaches. Here we describe two patients of same age, gender and stage with primary mediastinal B-cell lymphoma and an early relapse after the first courses of combination chemotherapy and irradiation of the mediastinum. One patient relapsed after a salvage therapy with allogeneic donor-related bone marrow transplantation and donor lymphocyte infusion but responded again with a continuing good partial remission after infusion of the chimeric anti-CD20 antibody IDEC-C2B8. For the other patient an allogeneic bone marrow transplantation was not possible. He finally failed to respond to salvage therapy with IDEC-C2B8 and died of progressive disease. The anti-CD20 antibody IDEC-C2B8 induced a partial remission in a patient with primary mediastinal B-cell lymphoma refractory to other therapeutic approaches, including allogeneic bone marrow transplanatation (alloBMT), donor lymphocyte infusion (DLI) and irradiation. The role of IDEC-C2B8 as a component of salvage regimens appears to be worthy for further evaluation in high-risk patients with primary mediastinal B-cell lymphoma

Role of crown-like side chains in the biological activity of substituted-phenoxazone drugs

The antitumour activity of a number of synthetic crown-ether analogues of actinomycin D (AMD) was investigated in order to test the role of side chains that can complex metal cations. The AMD analogues consisted of two series of phenoxazone derivatives substituted with either benzo-15-crown-5 or benzo-18-crown-6 and with different lengths of spacers between the crown groups and the phenoxazone chromophore. The biological activities of the synthetic compounds were investigated by examination of drug-induced apoptosis and cell cycle perturbations in a human leukemia MOLT-3 cell line by flow cytometry. A compound with dimethylaminopropyl side chains on the phenoxazone chromophore was used as a control; this molecule was shown to intercalate into DNA by UV-visible spectroscopy and was found to have considerable cytotoxic activity in the 1-9 microM concentration range. Compounds with five-membered crown-ether side chains showed biological activity comparable with the control drug, whereas increasing the length of the spacers between the crown groups and the phenoxazone chromophore reduced the cytotoxic effect of the drugs. Compounds with six-membered crown-ether side chains reduced stabilization of the DNA double helical structure and abolished biological activity. Cell cycle alterations were observed only in drug systems which demonstrated cytotoxic activity. Cell cycle regulation was found to be sensitive to minor modifications (elongation of the spacer by one methylene group) in the side chains of the benzo-15-crown-5 derivatives, indicating that such series of synthetic drugs may serve as useful probes for investigation of cell cycle regulation processes.

Relapse in childhood acute lymphoblastic leukemia is associated with a decrease of the Bax/Bcl-2 ratio and loss of spontaneous caspase-3 processing in vivo

Dysfunction of the p53/Bax/caspase-3 apoptosis signaling pathway has been shown to play a role in tumorigenesis and tumor progression, ie the development of acquired drug resistance. Low expression of the apoptosis inducer Bax correlates with poor response to therapy and shorter overall survival in solid tumors. In the present study, we analyzed the p53/Bax/caspase-3 pathway in a paired and an unpaired sample series of children with acute lymphoblastic leukemia (ALL) at initial diagnosis and relapse. The data demonstrate that both Bax expression levels and the Bax/Bcl-2 ratio are significantly lower in samples at relapse as compared with samples at initial diagnosis (P=0.013, Wilcoxon signed rank test (paired samples); P=0.0039, Mann-Whitney U test (unpaired samples)). The loss of Bax protein expression was not a consequence of Bax frameshift mutations of the G8 tract and could not be attributed to mutations of the p53 coding sequence (exons 5 to 8) which were detected to a similar extent in de novo ALL samples and at relapse. Analysis of the downstream effector caspase-3 showed loss of spontaneous caspase-3 processing at relapse. Whereas nine out of 14 (64%, paired samples) or 37 out of 77 (48%, unpaired samples) ALL patients at initial diagnosis displayed spontaneous in vivo processing of caspase-3, this was completely absent in patients at relapse (paired samples) or detected in only one out of 34 patients at relapse (2.9%, unpaired samples). We therefore conclude that in ALL relapse a severe disturbance of apoptotic pathways occurs, both at the level of Bax expression and caspase-3 activation.

Impaired BAX protein expression in breast cancer: mutational analysis of the BAX and the p53 gene

We have previously shown that the pro-apoptotic BAX protein is differentially expressed in breast cancer and in other epithelial tumors. In this line, a reduced BAX protein expression is a negative prognostic factor in various carcinomas including breast cancer. For p53, a trancriptional activator of BAX in apoptosis, mutations in the coding sequence were shown to modulate BAX protein expression in cell line models on the transcriptional level. We therefore investigated the BAX gene in 68 breast cancer specimens for the presence of mutations in the coding sequence by single-strand conformation polymorphism (SSCP)-PCR and direct sequencing. The expression of BAX protein was assessed by immunohistochemistry. In addition, we screened for mutations in the exons 5-8 of the p53 gene by SSCP-PCR to assess whether mutations in the DNA-binding domain of this upstream regulator of BAX gene transcription are responsible for differences in BAX protein expression. As previously observed, BAX was differentially expressed in the breast cancer samples, but no mutations in the coding sequence of the BAX gene were found besides a polymorphism in exon 6 at the position 552 (G->A) and additional intronic polymorphisms. In contrast, we identified 16 of 68 (23.5%) tumors to bear mutations in the p53 gene. In the subset of BAX-expressing tumors, the mutational inactivation of p53 did result in a reduced BAX protein expression (Fisher exact test, p = 0. 047). Nevertheless, we identified a subset of BAX-negative tumors lacking BAX or p53 mutations. Thus, additional, not yet identified regulators, apart from p53, appear to be involved in the regulation of BAX protein expression.

Impaired BAX protein expression in breast cancer: mutational analysis of the BAX and the p53 gene

We have previously shown that the pro-apoptotic BAX protein is differentially expressed in breast cancer and in other epithelial tumors. In this line, a reduced BAX protein expression is a negative prognostic factor in various carcinomas including breast cancer. For p53, a trancriptional activator of BAX in apoptosis, mutations in the coding sequence were shown to modulate BAX protein expression in cell line models on the transcriptional level. We therefore investigated the BAX gene in 68 breast cancer specimens for the presence of mutations in the coding sequence by single-strand conformation polymorphism (SSCP)-PCR and direct sequencing. The expression of BAX protein was assessed by immunohistochemistry. In addition, we screened for mutations in the exons 5-8 of the p53 gene by SSCP-PCR to assess whether mutations in the DNA-binding domain of this upstream regulator of BAX gene transcription are responsible for differences in BAX protein expression. As previously observed, BAX was differentially expressed in the breast cancer samples, but no mutations in the coding sequence of the BAX gene were found besides a polymorphism in exon 6 at the position 552 (G->A) and additional intronic polymorphisms. In contrast, we identified 16 of 68 (23.5%) tumors to bear mutations in the p53 gene. In the subset of BAX-expressing tumors, the mutational inactivation of p53 did result in a reduced BAX protein expression (Fisher exact test, p = 0. 047). Nevertheless, we identified a subset of BAX-negative tumors lacking BAX or p53 mutations. Thus, additional, not yet identified regulators, apart from p53, appear to be involved in the regulation of BAX protein expression.

Inhibition of in vitro spontaneous apoptosis by IL-7 correlates with bcl-2 up-regulation, cortical/mature immunophenotype, and better early cytoreduction of childhood T-cell acute lymphoblastic leukemia

In normal T-cell development, IL-7 plays a nonredundant role as an antiapoptic factor by regulating Bcl-2 expression in pro-T cells. In the current study, we addressed the roles of IL-7 and related cytokines as apoptosis-modulating factors in precursor T-cell acute lymphoblastic leukemia (T-ALL). To this end, leukemic blasts from pediatric patients with T-ALL were prospectively investigated as to their responsiveness to IL-7, IL-4, and IL-2 (in terms of modulation of spontaneous apoptosis, assessed by flow cytometry), cytokine receptor expression profiles, and expression levels of Bcl-2 and Bax proteins. IL-7, in contrast to IL-4 and IL-2, was highly efficient in apoptosis inhibition, and this effect correlated with the expression levels of IL-7Ralpha chain and with the up-regulation of Bcl-2 protein expression (P <.0001). Subclassification of T-ALL samples (n = 130) according to their in vitro IL-7 responses revealed that IL-7 refractory samples were more frequently positive for CD34 (P <.0001) and the myeloid-associated antigen CD33 (P =.01), whereas IL-7 responsiveness was associated with an expression of more mature differentiation-associated T-cell antigens (CD1a, surface CD3, CD4/8; P <.05). Furthermore, the extent of apoptosis inhibition by IL-7 in vitro quantitatively correlated with early cytoreduction as determined by the prednisone peripheral blood response on day 8 and cytoreduction in the marrow on day 15 (n = 87; P <.05). Multivariate analysis of the apoptosis-related parameters investigated, including spontaneous apoptosis, its inhibition by IL-7, and expression levels of Bcl-2 and Bax, showed that only IL-7 responsiveness has an independent impact on early cytoreduction (P <. 05), thus indicating a potential prognostic relevance of IL-7 sensitivity in T-ALL.

Detection of acute leukemia cells with mixed lineage leukemia (MLL) gene rearrangements by flow cytometry using monoclonal antibody 7.1

Translocations involving 11q23 are among the most common genetic abnormalities in hematologic malignancies, occurring in approximately 5-10% of acute lymphoblastic leukemia (ALL) and 5% of acute myeloblastic leukemia (AML). In 11q23 translocations, the mixed lineage leukemia (MLL) gene on chromosome 11, band q23, is usually disrupted. The human homologue of the rat NG2 chondroitin sulfate proteoglycan molecule, as detected by the monoclonal antibody (moab) 7.1, was shown to be expressed on leukemic cells with MLL rearrangements of children with acute leukemia. We further investigated the reactivity of the moab 7.1 on 533 cell samples of adults (n = 215) and children (n = 318) with acute leukemias (271 AML, 217 B-lineage ALL, 37 T-lineage ALL, eight CD7+ CD56+ myeloid/natural killer cell precursor acute leukemias) by flow cytometry. In AML, 38 samples were positive for moab 7.1 ('20%-cut-off-level'). These moab 7.1-positive AML cases revealed a myelomonocytic-differentiated immunophenotype with coexpression of the NK cell marker CD56 in 33 of 38 cases. Two of eight cell samples of the recently described CD7+ CD56+ myeloid/natural killer cell precursor acute leukemia entity reacted with moab 7.1. In ALL, 35 samples mostly of the pro-B-ALL subtype (33 pro-B-ALL, one common-ALL, one pre-B-ALL) were positive for moab 7.1. 58 (81%) of 72 samples with MLL rearrangements were positive for moab 7.1 including 28/31 with a t(4;11), 16/17 with a t(9;11), 3/5 with a t(11;19), and 2/6 with a del(11)(q23). All moab 7.1-positive ALL (n = 34) and childhood AML (n = 17) cases revealed MLL rearrangements as detected by Southern blot analysis and RT-PCR. However, 11 adults with AML, and one adult with moab 7.1-positive CD7+ CD56+ myeloid/natural killer cell precursor acute leukemia were negative for MLL rearrangements as proved by Southern blot analysis. We conclude that moab 7.1 is a sensitive but not entirely specific marker for the identification of 11q23-associated AML and ALL by flow cytometry in children and adults.

Clinical significance of P-glycoprotein expression and function for response to induction chemotherapy, relapse rate and overall survival in acute leukemia

BACKGROUND AND OBJECTIVES

A multidrug-resistance (MDR) phenotype mediated by P-glycoprotein (P-gp) contributes to chemotherapy failure in acute leukemia. However, the exact prognostic significance of this resistance mechanism is still unclear, mostly due to methodologic problems in P-gp detection. We therefore investigated, whether P-gp expression levels or functional P-gp activity better predict response to induction chemotherapy, relapse rate and overall survival in acute leukemia.

DESIGN AND METHODS

We examined cell samples of 121 adults with de novo acute myeloid leukemia (AML) and 102 children with newly diagnosed acute lymphoblastic leukemia (ALL) for P-gp expression and functional P-gp activity by flow cytometry. P-gp function was determined by the rhodamine 123 (rh123)-efflux test (AML n=121, ALL n=102) and P-gp expression levels using the P-gp specific monoclonal antibodies (moabs) MRK-16 (AML n=51, ALL n=31), 4.E3 (AML n=35, ALL n=32), or UIC-2 (AML n=68, ALL n=50). We correlated our findings with the immunophenotype, FAB morphology, cytogenetics and clinical data of the examined patients.

RESULTS

P-gp expression levels as detected by MRK-16 and 4.E3 were very low and did not differ between AML and ALL as estimated using relative fluorescence intensity (RFI) values and D-values by Kolmogorow-Smirnov (KS) statistics. For moab UIC-2, P-gp expression levels were higher in AML than in ALL. Within AML, moab UIC-2 mainly reacted with myelomonocytic-differentiated leukemic cells of the FAB M4/5 subtypes. No correlation between P-gp expression levels as detected by MRK-16, 4.E3 or UIC-2 and the response to induction chemotherapy or relapse rate, both in AML and ALL, was observed. However, a prognostic impact of P-gp expression levels on overall survival in AML was seen for moab MRK-16. Moreover, within AML, P-gp function was higher in immature blast cells as defined by immunophenotype and FAB morphology and correlated with response to induction chemotherapy, relapse rate, overall survival as well as cytogenetic risk groups. In ALL, the overall functional P-gp activity was lower than in AML and did not correlate with immunophenotypical subgroups, response to induction chemotherapy, relapse rate or overall survival.

INTERPRETATION AND CONCLUSIONS

Our data demonstrate a prognostic impact of P-gp in AML but not ALL and indicate that the functional rh123-efflux assay should be preferred for flow-cytometric P-gp evaluation in acute leukemia compared with P-gp expression analysis by monoclonal antibodies.

Constitutive expression levels of CD95 and Bcl-2 as well as CD95 function and spontaneous apoptosis in vitro do not predict the response to induction chemotherapy and relapse rate in childhood acute lymphoblastic leukaemia

CD95 (Fas/APO-1) expression and function and Bcl-2 expression, as well as spontaneous apoptosis in vitro, have been shown to be predictive markers for the in vivo response to chemotherapy in acute myeloid leukaemia (AML). To determine the clinical significance of apoptosis-regulating factors in acute lymphoblastic leukaemia (ALL), we investigated cell samples of children with ALL who had been included in the German ALL Berlin-Frankfurt-Münster (BFM) study using flow cytometry for constitutive expression levels of CD95 (n = 110) and Bcl-2 (n = 110). Furthermore, we determined the extent of spontaneous apoptosis in vitro (n = 102) and susceptibility to anti-CD95-induced apoptosis (CD95-sensitivity) (n = 97). We correlated these findings with the functional activity of the multidrug resistance (MDR)-associated P-glycoprotein (P-gp), as detected by the rhodamine123 efflux test, immunophenotype, cytogenetics and clinical data of the patients examined. Good responders to initial prednisone therapy ('prednisone response') revealed significantly higher Bcl-2 expression levels [5.4 +/- 3.4 relative fluorescence intensity (RFI), n = 68] than poor responders (3.7 +/- 2.6 RFI, n = 42; P = 0.002). There was no significant correlation between the other investigated parameters and prednisone response. Moreover, neither the CD95 and Bcl-2 expression levels nor the extent of spontaneous apoptosis in vitro, CD95 sensitivity or P-gp function were correlated with the response to induction chemotherapy or relapse rate, either for B-cell precursor ALL or T-cell ALL. No consistent pattern of change in CD95 (n = 10) and Bcl-2 expression (n = 9) was noted in cases studied at both initial diagnosis and relapse. In conclusion, our findings underline the different cell biological features of primary AML and ALL cells.

Weekly 24-hour infusion of high-dose 5-fluorouracil plus folinic acid in combination with mitomycin C for the treatment of advanced gastric cancer

PURPOSE

This study was performed to investigate the activity and safety of high dose 5-fluorouracil (5-FU) given as a weekly 24-hour infusion in combination with folinic acid plus mitomycin C in patients with advanced gastric cancer.

PATIENTS AND METHODS

Chemonaive patients with locally advanced inoperable, recurrent or metastatic gastric cancer were treated with 15 mg/m(2) i.v. mitomycin C as bolus on day 1 of a 7-week cycle followed by a 2-hour infusion of folinic acid (500 mg/m(2)) and a 24-hour infusion of 5-FU (2,600 mg/m(2)) given on days 1, 8, 15, 22, 29, and 36 as outpatient treatment.

RESULTS

Thirty evaluable patients (median age 58 years and median ECOG performance status 1) received 1-4 cycles (median 3). 53% of the patients had liver metastases. Treatment-related toxicity was low with 10% of patients experiencing diarrhea >/=grade 3, 3% mucositis grade 3 and 3% nausea grade 3 (CTC). Hematological toxicity was mild with 13% thrombopenia grade 3 and no leukopenia grade 4. Eleven patients achieved a partial remission (major response rate 37%; 95% confidence interval 22-53%). Median time to progression was 5 months and median overall survival time was 7 months.

CONCLUSION

This regimen is a well-tolerated outpatient treatment for patients with advanced gastric cancer with efficacy being comparable to other chemotherapy protocols.

Apoptosis-induced cleavage of beta-catenin by caspase-3 results in proteolytic fragments with reduced transactivation potential

Beta-catenin is a member of the Armadillo repeat protein family with a dual cellular function as a component of both the adherens junction complex and the Wnt/wingless signaling pathway. Here we show that beta-catenin is proteolytically cleaved during anoikis and staurosporine-induced apoptosis. Cleavage of beta-catenin was found to be caspase-dependent. Five cleavage products of beta-catenin were identified in vivo and after in vitro cleavage by caspase-3. Amino acid sequencing and mass spectrometry analysis indicated two caspase-3 cleavage sites at the C terminus and three further sites at the N terminus, whereas the central Armadillo repeat region remained unaffected. All beta-catenin cleavage products were still able to associate with E-cadherin and alpha-catenin and were found to be enriched in the cytoplasm. Functional analysis revealed that beta-catenin deletion constructs resembling the observed proteolytic fragments show a strongly reduced transcription activation potential when analyzed in gene reporter assays. We therefore conclude that an important role of the beta-catenin cleavage during apoptosis is the removal of its transcription activation domains to prevent its transcription activation potential.