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Trabectedin Reveals a Strategy of Immunomodulation in Chronic Lymphocytic Leukemia
Cancer Immunology Research, 2019
Chronic lymphocytic leukemia (CLL) is a B-cell neoplasia characterized by protumor immune dysregulation involving nonmalignant cells of the microenvironment, including T lymphocytes and tumor-associated myeloid cells. Although therapeutic agents have improved treatment options for CLL, many patients still fail to respond. Some patients also show immunosuppression. We have investigated trabectedin, a marine-derived compound with cytotoxic activity on macrophages in solid tumors. Here, we demonstrate that trabectedin induces apoptosis of human primary leukemic cells and also selected myeloid and lymphoid immunosuppressive cells, mainly through the TRAIL/TNF pathway. Trabectedin modulates transcription and translation of IL6, CCL2, and IFNα in myeloid cells and FOXP3 in regulatory T cells. Human memory CD8+ T cells downregulate PD-1 and, along with monocytes, exert in vivo antitumor function. In xenograft and immunocompetent CLL mouse models, trabectedin has antileukemic effects and an...
to improve the efficacy of therapeutic options in chronic lymphocytic leukemia (cll) an in vitro system to determine the response of mononuclear blood cells from blood of patients was elaborated. the study combines four approaches, i.e., cell viability, apoptosis rate, differential scanning calorimetry (DSc), and immunoblotting to develop personalized therapy protocols based on the cell sensitivity to drug exposure of individual cll patients. the complementary analyses were performed on 28 peripheral blood samples from previously untreated cll patients before therapy. the induction and progress of apoptosis in cll cells exposed in vitro to purine analogs combined with mafosfamide, i.e., cladribine + mafosfamide (CM) and fludarabine + mafosfamide (fM) were assessed using the above approaches. the changes in thermal profiles (decrease/loss of transition at 95±5˚C) coincided with an accumulation of apoptotic cells, a decrease in the number of viable cells, and differences in the expression of the apoptosis-related protein ParP-1. no significant changes were observed in the thermal profiles of nuclei isolated from cll cells resistant to the treatment. the complementary assays revealed a strong relationship between both the in vitro sensitivity of leukemia cells to drugs and the clinical response of the patients, determined usually after the sixth course of treatment (after ~6 months of therapy). as a summary of studies followed by complementary tests, our findings demonstrate the value of in vitro exposure of cll cell samples to drugs intended to treat cll patients, before their administration in order to recommend the most suitable and effective therapy for individual patients.
International Journal of Oncology, 2015
to improve the efficacy of therapeutic options in chronic lymphocytic leukemia (cll) an in vitro system to determine the response of mononuclear blood cells from blood of patients was elaborated. the study combines four approaches, i.e., cell viability, apoptosis rate, differential scanning calorimetry (DSc), and immunoblotting to develop personalized therapy protocols based on the cell sensitivity to drug exposure of individual cll patients. the complementary analyses were performed on 28 peripheral blood samples from previously untreated cll patients before therapy. the induction and progress of apoptosis in cll cells exposed in vitro to purine analogs combined with mafosfamide, i.e., cladribine + mafosfamide (CM) and fludarabine + mafosfamide (fM) were assessed using the above approaches. the changes in thermal profiles (decrease/loss of transition at 95±5˚C) coincided with an accumulation of apoptotic cells, a decrease in the number of viable cells, and differences in the expression of the apoptosis-related protein ParP-1. no significant changes were observed in the thermal profiles of nuclei isolated from cll cells resistant to the treatment. the complementary assays revealed a strong relationship between both the in vitro sensitivity of leukemia cells to drugs and the clinical response of the patients, determined usually after the sixth course of treatment (after ~6 months of therapy). as a summary of studies followed by complementary tests, our findings demonstrate the value of in vitro exposure of cll cell samples to drugs intended to treat cll patients, before their administration in order to recommend the most suitable and effective therapy for individual patients.
In vitro proliferative response of chronic lymphocytic leukemia
1977
Chronic lymphocytic leukemia (CLL) is a lymphoproliferative disease with accumulation of small, morphologically mature lymphocytes, in the peripheral blood. There is now a large amount of evidence that this malignancy mainly affects bone marrow-derived cells (B lymphocytes)1,12,16,19. 31, and that the impairment of their immunological functions may cause most of the clinical manifestations of the disease 20. CLL lymphocytes have been repeatedly shown to display in vitro an abnormal and delayed response to mitogens, such as phytohaemagglutinin, pokeweed mitogen, concanavalin A, as well as specific antigens 15,17. 26.27 Many hypotheses have been put forward to explain this low reactivity in vitro, involving either a dilution effect of the residual thymus-derived cells (T lymphocytes) s,33, or an intrinsic alteration in their proliferative capacity 4. n. 17, 20,23. It has also been reported recently that CLL serum has an inhibitory effect on the blastogenesis of autologous lymphocytes 2s'3°. However, in contrast to the extensive body of information on the behaviour of CLL lymphocytes, relatively little is known about the in vitro functions of the leukemic cells from tissues other than the peripheral blood, such as the bone marrow and lymph nodes. In this paper we will describe the results of an investigation on the immunological responsiveness of peripheral, bone marrow and lymph node CLL lymphocytes, as well as the effect of autologous serum on their mitogenic response.
The biology and treatment of chronic lymphocytic leukemia
Annals of Oncology, 2006
Major advances have occurred in our understanding of the biology, immunology, and opportunities for treatment of chronic lymphocytic leukemia (CLL) in recent times. Surface antigen analysis has helped us define classical CLL and differentiate it from variants such as marginal zone leukemia, mantle cell leukemia, and prolymphocytic leukemia. An important observation has been that the B-cells in indolent types of CLL, which do not require therapy, have undergone somatic hypermutation and function as memory B-lymphocytes whereas those more likely to progress have not undergone this process.
Clinical Cancer Research, 2010
Inhibition of the antiapoptotic BCL2 family is one of the most promising areas of anticancer drug development. However, ABT-737, a specific BCL2 inhibitor, is neither orally bioavailable nor metabolically stable. To overcome these problems, the structurally related molecule ABT-263 was synthesized and recently entered clinical trials in hematologic malignancies, including chronic lymphocytic leukemia (CLL). Almost all laboratory studies have been carried out with ABT-737 rather than ABT-263, the drug being used in clinical trials. Currently there are no published data on the comparative effects of these inhibitors. To gain insight into the potential value or limitations of ABT-263 in the clinic, we assessed its ability to induce apoptosis in clinically relevant cellular models of CLL. The susceptibility of freshly isolated primary CLL cells to these inhibitors was compared in standard culture conditions and in conditions that more closely mimic in vivo conditions in a whole blood assay system. ABT-737 was more potent than ABT-263 at inducing apoptosis in CLL cells. In whole blood, approximately 100-fold higher concentrations of both drugs were required to induce apoptosis. We found that ABT-263 was highly bound by albumin and that an increased albumin binding of ABT-263 as compared with ABT-737 accounted for the differential sensitivity of CLL cells. Our data indicate that the exquisite in vitro sensitivity of CLL cells to BCL2 inhibitors may be lost in vivo due to high cell densities and the albumin binding of ABT-263. Modification of ABT-263 may yield a BCL2 inhibitor with greater bioavailability and more favorable pharmacokinetics.
B-chronic lymphocytic leukemia: practical aspects
Hematological Oncology, 2002
B-CLL is the most common adult leukemia in the Western world. It is a neoplasia of mature looking B-monoclonal lymphocytes co-expressing the CD5 antigen (involving the blood, the bone marrow, the lymph nodes and related organs). Much new information about the nature of the neoplastic cells, including chromosomal and molecular changes as well as mechanisms participating in the survival of the leukemic clone have been published recently, in an attempt to elucidate the biology of the disease and identify prognostic subgroups. For the time being, clinical stage based on Rai and Binet staging systems remains the strongest predictor of prognosis and patients' survival, and therefore it affects treatment decisions. In the early stages treatment may be delayed until progression. When treatment is necessary according to well-established criteria, there are nowadays many different options. Chlorambucil has been the standard regimen for many years. During the last decade novel modalities have been tried with the emphasis on fludarabine and 2-chlorodeoxyadenosine and their combinations with other drugs. Such an approach offers greater probability of a durable complete remission but no effect on overall survival has been clearly proven so far. Other modalities, included in the therapeutic armamentarium, are monoclonal antibodies, stem cell transplantation (autologous or allogeneic) and new experimental drugs. Supportive care is an important part of patient management and it involves restoring hypogammaglobulinemia and disease-related anemia by polyvalent immunoglobulin administration and erythropoietin respectively.
Medical Oncology, 2011
Malfunctions in the regulation of apoptosis cause the accumulation of malignant, long-lived B CD19?/ CD5? cells in chronic lymphocytic leukemia (CLL). The primary goal in CLL therapy is to overcome resistance to apoptosis and efficiently trigger programmed cell death in leukemic cells. This study demonstrated that the in vivo responses of malignant cells from CLL patients after administration of purine analogs (cladribine/fludarabine) with cyclophosphamide vary significantly. For comparative purposes, the sensitivity of leukemic cells obtained from the same CLL patients to conventional purine analogs and the selective CDK inhibitor R-roscovitine (ROSC) was determined, with and without the addition of an alkylating agent, prior to the onset of in vivo therapy. The kinetics and rate of spontaneous and drug-induced apoptosis of CLL cells under ex vivo conditions differed significantly between patients, mirroring the variability observed during in vivo treatment. Interestingly, individual patients' leukemic cells were comparably sensitive to the drugs under both conditions. Of the drugs examined, ROSC exerted the highest therapeutic efficacy under ex vivo conditions. Our results indicate that ex vivo testing might be useful for identifying the most potent first-line therapeutic regimen for specific CLL patients and possibly for the design of therapies tailored for individual CLL patients.
International Journal of Cancer, 1989
Five patients with B-cell chronic lymphocytic leukemia (B-CLL) were treated with 6 courses of the antLCD5 immunotoxin TIOI-ricin A chain (TIOI-RTA). Each course consisted of 8 biweekly infusions of TIOI-RTA (7 or 14 mg/m2). The immunotoxin was well tolerated in all cases with no major toxicities. Though saturation of circulating leukemic cell-associated target antigen was demonstrated by FACS analysis in all patients, no intact immunotoxin was detected in bonemarrow or lymph-node aspirates. Pharmacokinetic studies revealed rapid clearance of TIOI-RTA. with a half-life of 43 min. None of the patients developed detectable titers of antibody against either TI01 murine antibody or rich A chain. Clinical response was limited to a rapid and transient fall in WBC count lasting less than 24 hr, most likely secondary to the antibody portion of the conjugate. In vifro, fresh 6-CLL cells were resistant to TIOI-RTA at concentrations up to IO-*n, while fresh malignant T-cells with a 10-fold increase in expression of CD5 antigen were sensitive. In the presence of the enhancing agent human serum albumin-monensin, fresh 6-CLL cells were sensitive to TIOI-RTA, with an IDSo more than 2 logs below the maximal concentration of immunotoxin achieved in vivo. We conclude that TIOI-RTA is a potentially useful agent in the treatment of T-cell leukemias. In the presence of HSA-monensin, this spectrum of activity may be extended to 6-CLL. Clinical parameters Patients were closely observed for adverse reactions. Vital signs were monitored every 15 min during infusion. Electrolytes, renal and hepatic function, complete blood count with differential, prothrombin time, and activated partial thrombo-4T0 whom reprint requests should be sent, at