Cytokines and molecular therapy最新文献

Three strategies were used to evaluate 38C13 B-cell lymphoma-specific idiotype immunization to protect against subsequent lymphoma challenge in C3H/He mice. It was observed that tumor-specific immunity could be induced by immunization with (i) KLH-conjugated 38C13 B-cell lymphoma idiotype in complete Freund's adjuvants (survival rate 80%), (ii) dendritic cells pulsed in vitro with native idiotype protein (survival rate 80%), and (iii) bispecific antibodies composed of B-lymphoma-related idiotype and an MHC class II binding moiety (survival rate 40%). Presentation of idiotype determinants by dendritic cells or bispecific antibody resulted in lymphoma-specific immunity and obviated the requirement for carrier protein or adjuvant. Moreover, primed dendritic cells induced predominant development of a tumor-specific T-cell response. Each of these immunization strategies resulted in long-term survival without the emergence of idiotype variants or the induction of tumor dormancy.

Alleles of the IL-1 genes are associated with several autoimmune and inflammatory diseases, where they tend to have a role in the severity of the disease rather than in susceptibility to the disease itself. Allele 2 of the variable number tandem repeat (VNTR) polymorphism in the IL-1 receptor antagonist (IL-1ra) gene was the first marker of the IL-1 cluster to be associated in this way with severity of chronic, systemic and local inflammatory diseases. Because of the role that IL-1 also plays in the pathobiology of certain hematopoietic disorders, we aimed at examining the allelic distribution of the IL-1ra VNTR in leukemias, lymphomas and related malignancies. While in patients with chronic lymphocytic leukemia (CLL), hairy cell leukemia (HCL), multiple myeloma (MM) and related disorders, primary acute myeloid leukemia (AML), chronic myeloid leukemia (CML), and Hodgkin's disease (HD), the allelic distribution of IL-1RN was comparable to that seen in healthy control subjects, in a small group of patients with secondary AML the frequency of the IL-1RN*4 allele appeared to be significantly increased.

The chimeric Bcr-Abl oncogene has been implicated in the pathogenesis of chronic myelogenous leukemia (CML) and Philadelphia chromosome (Ph1)-positive acute lymphocytic leukemia (ALL). The Bcr-Abl protein is a complex structure comprising discrete domains associated with specific biochemical and biological functions. These domains function through their ability to activate distinct signal transduction pathways responsible for Bcr-Abl's oncogenic behavior. This review will present our current understanding of signal transduction pathways involved in Bcr-Abl-induced pathophysiology, with particular emphasis on potential targets for therapeutic intervention.

We have assessed in a phase I/II clinical study the tolerability and efficacy of long-term application of recombinant human interleukin-3 (rh-IL-3) in combination with antithymocyte globulin (ATG) and cyclosporin A (CSA) in 13 patients with aplastic anemia who were refractory to or relapsed after previous immunosuppressive treatment. Four cohorts of three patients were consecutively enrolled so that they received rh-IL-3 on days 9, 6, 3 and 1 after start of ATG/CSA treatment. Yeast-derived recombinant human IL-3 was administered by daily subcutaneous injection until day 90 at a dosage of 250 micrograms/m2. Long-term application of rh-IL-3 was well tolerated. The combination of rh-IL-3 with immunosuppression did not modify the known toxicities of ATG and CSA. Incidence and severity of rh-IL-3-related adverse events was less than in other phase I/II trials of rh-IL-3 as single-agent therapy. One might speculate that co-medication with CSA alleviates rh-IL-3-induced side effects. Three of eight patients with refractory AA and all four patients with relapsed AA responded to the combined treatment within four months. The median time to response was 91.5 days. There was evidence for an rh-IL-3-dependent response in two patients. Long-term rh-IL-3 did not cause stem cell exhaustion. One patient died early during the course of the study from EBV-driven lymphoproliferative disease. Two patients developed acute myeloid leukemia 4 and 22 months after cessation of rh-IL-3. In conclusion, long-term rh-IL-3 in combination with immunosuppression is well tolerated. The response rate to the combined treatment in refractory and relapsed AA was high. Recombinant human IL-3-dependent responses suggest efficacy. A prospective randomized trial comparing immunosuppression alone versus a combination with rh-IL-3 is warranted.

Management of acute lymphoblastic leukemia (ALL) patients may include growth factors (GFs) to reduce post-chemotherapy aplasia. A potential risk of GF administration is a stimulatory signal on the leukemic population. In the present study we investigated the proliferative and programmed cell death (PCD) effect of two cytokines that have recently entered clinical use, stem cell factor (SCF) and the granulocyte colony stimulating factor/IL-3 fusion molecule (PIXY-321), on 14 ALL samples. The activity of IL-7, a cytokine involved in the regulation of ALL cell proliferation, was also tested alone and in combination with these two cytokines. Using the acridine orange flow cytometric technique and the clonogenic assay, we showed that none of these cytokines was capable of significantly increasing the mean percentage of S-phase cells and CFU-L number. A mean decrease of G0 cells from 60.6% to 52.6% (p = 0.02), coupled by a significant increase of G1 cells from 28.2% to 37.9% (p = 0.003) was demonstrated in the presence of PIXY-321. IL-7 alone and in combination with either PIXY-321 or SCF induced similar changes in the percentage of cells in G0 and G1. SCF showed no activity on G0 depletion. When each individual samples was analyzed separately, some heterogeneity was observed. An increase of S phase was recorded in a proportion of cases after SCF and PIXY-321 exposure. However, none of the cytokines evaluated by a clonogenic assay following liquid culture was capable of maintaining or promoting self-renewal of leukemic precursors, as determined by plating fresh cells at time 0. Detection of cytokine effects of apoptosis showed that SCF and PIXY-321 did not significantly reduce the mean percentage of cells in PCD, whereas a significant protective effect was observed in the presence of IL-7 (p = 0.02). We conclude that PIXY-321 and, to a further extent, SCF fail to induce leukemic lymphoid cell proliferation, and do not protect cells from entering apoptosis. These in vitro findings may be useful for ALL clinical trial design.

Involvement of tumor necrosis factor (TNF) in bone marrow transplantation (BMT)-associated complications has been documented. Biological response to TNF requires interaction with specific cell membrane receptors. Extracellular domains of these receptors are released into body fluids as soluble molecules, and participate in the bioactivity of TNF. Serum levels of p55 and p75 soluble tumor necrosis factor receptors (sTNFR) were determined in 34 patients with different diseases who underwent BMT. Sequential studies initiated 10 days before BMT and continued up to 110 days post-transplantation showed that p55 and p75 sTNFR levels were elevated significantly in patients who subsequently developed major transplant-related complications (TRC). Moreover, both sTNFR levels were increased 2- to 3-fold over control values during post-BMT febrile periods in those patients who at a later stage suffered major TRC. These results indicate that the serum level of sTNFR may be used as a prognostic marker for major TRC in BMT.

Cancer vaccines are genetically modified tumor cells that, by cytokine secretion or by expression of costimulatory molecules, are capable of mobilizing the host's immune system to destroy tumor cells. We have used adenovirus-enhanced transferrinfection (AVET) for the generation of cancer vaccines. This is a highly efficient method to deliver various genes into a large proportion of tumor cells, making further selection unnecessary. We found in the mouse M-3 melanoma model that two consecutive vaccinations with transfected cells secreting IL-2 protect animals from tumor development by a subsequent challenge, and result in long-lasting tumor-specific immunity dependent on both CD4+ and CD8+ T cells. Patterns of lymphocyte recirculation and the need for CD4+ T cells indicated that the role of IL-2 is not merely local 'replacement of help', as has been proposed before. Instead, our findings suggest a three-stage process for the generation of effector T cells after vaccination with IL-2 secreting tumor cells: (1) tumor antigen uptake and processing at the site of injection by APCs, (2) migration of APCs into the regional draining lymph nodes where T-cell priming occurs, and (3) recirculation of activated cytotoxic T cells, that recognize and eliminate distant tumor cells. This model also implies that allogeneic tumor cells or synthetic tumor antigens may be used with success in future cancer vaccines.

Molecular cytogenetics provides a powerful link between molecular genetic analysis and chromosome morphology, allowing one to pinpoint structurally aberrant chromosome regions on the molecular level. Fluorescence in situ hybridization with selected DNA probes allows the design of efficient and sensitive tools for the diagnosis of chromosomal aberrations present in tumor cells. Comparative genomic hybridization (CGH) allows the identification of chromosomal imbalances in a comprehensive manner, and is applied to solid tumors and hematological malignancies in order to (i) identify clonal differences within a specimen, (ii) contribute to tumor classifications, (iii) identify recurrent chromosomal gains and losses as starting points for the characterization and isolation of pathogenetically relevant genes, such as proto-oncogenes and tumor suppressor genes respectively, (iv) identify imbalances of prognostic relevance, (v) detect high-copy-number amplification and other markers of genetic instability, and (vi) analyze chromosomal imbalances during tumor progression.

The expression of a variety of stimulatory molecules by tumor cells can lead to tumor rejection and the development of systemic immunity by T cells. The fact that some tumor cells naturally express such determinants leads to the hypothesis that progressive tumor growth may be a reflection of problems with the host immune system. To test this, we compared the signal-transducing ability of T cells from mice inoculated with parental tumors (PTB) with that of T cells from mice immunized with IL-2-secreting tumor cells (ITB). Our results demonstrated that following T-cell activation, higher total kinase activity was associated with the signal-transducing zeta chain in ITB mice compared with PTB mice. Western blotting following stimulation of T cells with parental or genetically engineered IL-2-secreting, B7+ tumor cells revealed increased protein tyrosine phosphorylation in lysates derived from ITB compared with PTB T cells, demonstrating that tumor-derived IL-2 could influence signaling. Taken together, the findings are consistent with the hypothesis that tumor-derived IL-2 preserves the signal-transducing ability of immunocompetent T cells, but is ineffective when they are immunosuppressed. These results suggest that IL-2-secreting tumor cell vaccines might be useful as adjuvant therapy to prevent the outgrowth of micrometastases, following tumor resection, once immune function has normalized.

Ex vivo gene marking of normal and malignant hemopoietic cells allows the cells to be subsequently tracked in vivo. Marking has shown that even when marrow is in remission, it may contain malignant cells that contribute to relapse. These studies have also shown that it is possible to obtain long-term gene expression in human long-lived hemopoietic progenitor cells and T lymphocytes in vivo. Current marker studies use two distinguishable vectors to track two distinctively treated cell populations in a single individual. This modification greatly increases the power of the technique. It is now possible to study the effects of purging on residual malignant cells in marrow, to determine the action of growth-promoting agents (such as cytokines and stroma) on short- and long-term repopulation by transduced marrow, and to discover which phenotypic subsets of hemopoietic progenitor cells have long-term repopulating potential. The information gained will be invaluable for improving therapeutic gene transfer protocols in which marrow-derived cells are the targets.