Ex vivo activity of thalidomide in childhood acute leukemia

Thalidomide is a drug with anti-angiogenic, anti-inflammatory, immunomodulatory and anti-cancer properties that were found to inhibit the production of TNF-alpha in vitro, stimulate reactive oxygen species production, and inhibit VEGFR in acute leukemias. Ex vivo activity of thalidomide as a single agent and in combination with prednisolone or cytarabine in childhood acute leukemias was analyzed. Forty samples of childhood acute lymphoblastic leukemia (ALL) and 13 acute myeloid leukemia (AML) were tested for cytotoxicity by the MTT assay and cell cycle phases by flow cytometry. Control studies were performed on 9 samples of normal lymphocytes and 4 cell lines. A weak anti-leukemic activity of thalidomide against childhood leukemic samples was observed. However, in the presence of thalidomide, cytotoxicity of prednisolone or cytarabine, increased 3.3-fold and 2.7-fold, respectively, in childhood ALL but was not changed in AML. Thalidomide increased apoptosis in lymphoblasts, and modulated cell cycle arrest caused by prednisolone but not cytarabine in childhood acute lymphoblastic leukemia samples. Thalidomide potentiated ex vivo sensitivity of childhood ALL cells to prednisolone and cytarabine, while no sensitization effect was observed in AML cells.     

Modulation of in vitro chemosensitivity in acute myelogenous leukemia cell line by GM-CSF: opposing effects observed with different cytotoxic drugs and time exposure

In some studies the GM-CSF (granulocyte-macrophage colony-stimulating factor) increased the in vitro sensitivity of acute myeloid leukemia (AML) cells to cytosine arabinoside (Ara-C), however, in clinical trials no favorable effects were shown. We used a GM-CSF responsive AML cell line (AML 193) to test the effects of growth stimulation on in vitro efficacy of Ara-C and methotrexate (MTX). In 6 days continuous exposure, dose dependent Ara-C cytotoxicity was counteracted by GM-CSF. Conversely, MTX cytotoxicity was increased significantly. However, in a short term treatment (24 h, high doses) the GM-CSF increased both MTX and Ara-C cytotoxicity. These effects might depend on different drug regimens and cell features.     

Ex vivo drug resistance profile in childhood acute myelogenous leukemia: no drug is more effective in comparison to acute lymphoblastic leukemia

Therapy results in childhood acute myelogenous leukemia (AML) differ from those of acute lymphoblastic leukemia (ALL). Cellular drug resistance might be one of the reasons of therapy failure in AML. The aim of the study was the analysis of ex vivo drug resistance profile in childhood initial and relapsed AML in comparison to initial ALL. Fifty-three AML samples were tested for chemosensitivity and results were compared with those of 106 initial ALL samples. Ex vivo drug resistance was tested by means of the MTT assay. Up to 29 cytotoxic drugs were tested for each patient. When compared to de nova ALL samples, myeloblasts from initial AML samples were significantly more resistant to most tested drugs, except cytarabine, mercaptopurine and thioguanine. Relapsed AML samples, in relation to initial AML samples, showed comparable sensitivity to cytarabine, idarubicin, fludarabine and cladribine. Patients, who have died due to refractory or relapsing disease, were already on first diagnosis 2-fold more resistant to cytarabine, 6.4-fold more resistant to cisplatin and 3-fold more resistant to carboplatin, when compared to those who stay in remission. Resistance to prednisolone was observed in 85% initial and all relapsed AML samples, in comparison to 33% of ALL samples. Resistance to cytarabine occurred in 2.1% of ALL and 12% of AML cases while a patient with Down syndrome presented the most sensitive drug resistance profile. In conclusion this study shows that no drug was found which, on average, was more effective in AML than in ALL samples. The sensitivity of myeloblasts to platinum derivatives might have prognostic value.     

Childhood T-cell acute lymphoblastic leukemia: the Dana-Farber Cancer Institute acute lymphoblastic leukemia consortium experience.

PURPOSE: T-cell acute lymphoblastic leukemia (T-ALL) accounts for 10% to 15% of newly diagnosed cases of childhood acute lymphoblastic leukemia (ALL). Historically, T-ALL patients have had a worse prognosis than other ALL patients. PATIENTS AND METHODS: We reviewed the outcomes of 125 patients with T-ALL treated on Dana-Farber Cancer Institute (DFCI) ALL Consortium trials between 1981 and 1995. Therapy included four- or five-agent remission induction; consolidation therapy with doxorubicin, vincristine, corticosteroid, mercaptopurine, and weekly high-dose asparaginase; and cranial radiation. T-ALL patients were treated the same as high-risk B-progenitor ALL patients. Fifteen patients with T-cell lymphoblastic lymphoma were also treated with the same high-risk regimen between 1981 and 2000. RESULTS: The 5-year event-free survival (EFS) rate for T-ALL patients was 75% +/- 4%. Fourteen of 15 patients with T-cell lymphoblastic lymphoma were long-term survivors. There was no significant difference in EFS comparing patients with T-ALL and B-progenitor ALL (P =.56), although T-ALL patients had significantly higher rates of induction failure (P <.0001), and central nervous system (CNS) relapse (P =.02). The median time to relapse in T-ALL patients was 1.2 years versus 2.5 years in B-progenitor ALL patients (P =.001). There were no pretreatment characteristics associated with worse prognosis in patients with T-ALL. CONCLUSION: T-ALL patients fared as well as B-progenitor patients on DFCI ALL Consortium protocols. Patients with T-ALL remain at increased risk for induction failure, early relapse, and isolated CNS relapse. Future studies should focus on the identification of and treatment for T-ALL patients at high risk for treatment failure.     

Rearranged T-cell receptor beta genes represent powerful targets for quantification of minimal residual disease in childhood and adult T-cell acute lymphoblastic leukemia.

Current MRD studies in T-cell acute lymphoblastic leukemia (T-ALL) mainly use T-cell receptor gamma, delta and SIL-TAL1 gene rearrangements as MRD-PCR targets. However, low frequency or limited diversity of these markers restricts the number of evaluable patients, particularly because two markers are recommended for MRD monitoring. Hence, we developed a new strategy implementing the TCR beta (TCRB) locus for MRD quantification. The frequency and characteristics of complete and incomplete TCRB rearrangements were investigated in 53 childhood and 100 adult T-ALL patients using the BIOMED-2 multiplex PCR assay. Clonal rearrangements were identified in 92% both childhood and adult T-ALL (Vbeta-Dbeta-Jbeta rearrangements in 80%, Dbeta-Jbeta rearrangements in 53%). Comparative sequence analysis of 203 TCRB recombinations revealed preferential usage of the 'end-stage' segment Jbeta2.7 in childhood T-ALL (27%), whereas Jbeta2.3 was most frequently involved in adult T-ALL (24%). In complete rearrangements, three downstream Vbeta segments (19-1/20-1/21-1) were preferentially used. Subsequently, a TCRB real-time quantitative PCR assay to quantify MRD with 13 germline Jbeta primer/probe combinations and allele-specific oligonucleotides was developed and applied to 60 clonal TCRB rearrangements. The assay allowed the detection of one leukemic cell within at least 10(4) polyclonal cells in 93% of cases and will be of high value for future MRD studies.     

Efficient formation of cytosine arabinoside-5'-triphosphate in leukemic blasts of human T-cell acute lymphoblastic leukemia

The potential usefulness of cytosine arabinoside (ara-C) in the treatment of T-cell acute lymphoblastic leukemia (T-ALL) was studied by measuring the influx of ara-C into the lymphoblasts and the conversion of ara-C to its triphosphate form (ara-CTP) in lymphoblasts from the bone marrow of eighteen patients of T-ALL. Intracellular accumulation of ara-CTP was 3.5 times greater in T-cell lymphoblasts than in non-T or AML blasts. The increased formation of ara-CTP in T-ALL cell may be correlated with the good clinical response of T-ALL patients to the treatment with ara-C in combination with mitoxantrone.     

rhG-CSF对Ara-C杀伤急性髓性白血病细胞影响的实验研究

目的探讨ｒｈＧ－ＣＳＦ对２１例急性髓性白血病（ＡＭＬ）细胞体外对阿糖胞苷（Ａｒａ－Ｃ）敏感性的影响。方法采用ＭＴＴ法检测Ａｒａ－Ｃ的细胞毒作用。结果ｒｈＧ－ＣＳＦ可显著增强Ａｒａ－Ｃ对耐药ＡＭＬ细胞的毒性,与对照组相比Ｐ＜０．０５;结论ｒｈＧ－ＣＳＦ可能通过促进耐药ＡＭＬ细胞进入增殖周期,而增强Ａｒａ－Ｃ对耐药ＡＭＬ细胞的毒性,从而具有耐药的逆转效应,预示着ｒｈＧ－ＣＳＦ与Ａｒａ－Ｃ联合运用治疗耐药ＡＭＬ的潜在价值     

Discriminant function analysis as decision support system for the diagnosis of acute leukemia with a minimal four color screening panel and multiparameter flow cytometry immunophenotyping.

Despite several recommendations for standardization of multiparameter flow cytometry (MFC) the number, specificity and combinations of reagents used by diagnostic laboratories for the diagnosis and classification of acute leukemias (AL) are still very diverse. Furthermore, the current diagnostic interpretation of flow cytometry readouts is influenced arbitrarily by individual experience and knowledge. We determined the potential value of a minimal four-color combination panel of 13 monoclonal antibodies (mAbs) with a CD45/sideward light scatter-gating strategy for a standardized MFC immunophenotyping of the clinically most relevant subgroups of AL. Bone marrow samples from 155 patients with acute myeloid leukemia (AML, n=79), B-cell precursor acute lymphoblastic leukemia (BCP-ALL, n=29), T-cell precursor acute lymphoblastic leukemia (T-ALL, n=12) and normal bone marrow donors (NBMD, n=35) were analyzed. A knowledge-based learning algorithm was generated by comparing the results of the minimal panel with the actual diagnosis, using discriminative function analysis. Correct classification of the test sample according to lineage, that is, BCP-ALL, T-ALL, AML and differentiation of NBMD was achieved in 97.2% of all cases with only six of the originally applied 13 mAbs of the panel. This provides evidence that discriminant function analysis can be utilized as a decision support system for interpretation of flow cytometry readouts.     

Anti-GD3 monoclonal antibody analysis of childhood T-cell acute lymphoblastic leukemia: detection of a target antigen for antibody-mediated cytolysis

We have demonstrated in previous studies significant quantitative differences in the ganglioside content of leukemia cell membranes within immunological subclasses of acute lymphoblastic leukemia (ALL): The disialoganglioside GD3 (disialolactosylceramide) is increased in lymphoblasts with a T-cell immunophenotype compared to non-T-ALL blasts. Utilizing an indirect immunofluorescence assays with a monoclonal antibody to GD3(R24), pretreatment leukemic lymphoblasts from 80 children with ALL were assayed for GD3 expression. GD3 was observed in 75% of leukemic samples in which lymphoblasts exhibited a T-cell phenotype, whereas none of the 33 non-T-ALL samples tested exhibited GD3. Correlation between the expression of GD3 and various antigenic determinants of T-cell differentiation was restricted to CD2; 75% of CD2-negative T-cell ALL blasts failed to express GD3. Anti-GD3 immunoreactivity to T-ALL samples was not restricted to R24 in that two other monoclonal anti-GD3 antibodies were similarly reactive to T-ALL blasts. In vitro incubation of T-cell lymphoblasts with the anti-GD3 antibodies, R24 and C281 and human serum resulted in significant cytotoxicity, and R24 also mediated antibody-dependent cellular cytotoxicity by normal effector cells. Cytotoxicity was specific for those T-ALL blast cell populations which reacted with anti-GD3 as assessed by immunofluorescence microscopy. Since immunoreactivity with monoclonal antibody to GD3 was exclusively observed in a large population of immunophenotypically defined T-cell leukemic lymphoblasts, these studies suggest a possible immunodiagnostic and immunotherapeutic potential for anti-GD3 monoclonal antibodies in T-cell lymphoblastic malignancies.     

The analysis of correlations between drug resistance and clinical/laboratory measures found in a group of children with all treated by ALL-BFM 90 protocol

This study was designed to assess the predictive value of an MTT (3-[4,5-dimethylthiazol-2,5-diphenyl] tetrazolium bromide) in vitro assay for the evaluation of leukemic cell resistance/sensitivity to cytotoxic drugs, and to compare these results with clinical and laboratory parameters in cases of childhood acute lymphoblastic leukemia (ALL).The chemoresistance of leukemic cells was ascertained by means of an MTT assay in 32 previously untreated children with ALL. The children were treated using the protocol ALL-BFM 90. Statistical correlations were made between in vitro drug resistance to anti-cancer drugs: prednisolone (PRED), vincristine (VCR),daunorubicin (DNR), etoposide (VP-16) and cytosine arabinoside (ARA-C) and in vivo clinical and laboratory parameters: age, sex, risk factor (RF), leukocytes (WBC)and absolute number of blast cells (BC) at diagnosis (BC0), BC at day 8 (BC8), the percentage of blast cells in bone marrow at day 15 (BM15) and at day 33 (BM33),and leukocyte surface antigens CD3, CD4, CD5, CD8, CD10, CD19, CD20, HLADR.     

In vitro drug resistance to imatinib and mutation of ABL gene in childhood Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia

Imatinib, the ABL kinase inhibitor, is used not only for Philadelphia chromosome-positive (Ph + ) chronic myelogenous leukemia, but also for Ph + acute lymphoblastic leukemia (ALL), although resistance to the drug tends to develop in an early stage of the clinical course. We describe a childhood refractory Ph + ALL patient in whom progressive resistance to imatinib was correlated with the appearance of a mutation in the BCR-ABL kinase domain and in vitro drug resistance to imatinib as determined by the methyl-thiazol-tetrazolium (MTT) assay. A missense mutation of T to C (Y253H) of the ABL gene was identified in the resistant clone, suggesting that this mutation may play an etiological role in the rapid loss of drug sensitivity.     

Activating mutations in NOTCH1 in acute myeloid leukemia and lineage switch leukemias.

Activating mutations in NOTCH1 are found in over 50% of human T-cell lymphoblastic leukemias (T-ALLs). Here, we report the analysis for activating NOTCH1 mutations in a large number of acute myeloid leukemia (AML) primary samples and cell lines. We found activating mutations in NOTCH1 in a single M0 primary AML sample, in three (ML1, ML2 and CTV-1) out of 23 AML cell lines and in the diagnostic (myeloid) and relapsed (T-lymphoid) clones in a patient with lineage switch leukemia. Importantly, the ML1 and ML2 AML cell lines are derived from an AML relapse in a patient initially diagnosed with T-ALL. Overall, these results demonstrate that activating mutations in NOTCH1 are mostly restricted to T-ALL and are rare in AMLs. The presence of NOTCH1 mutations in myeloid and T-lymphoid clones in lineage switch leukemias establishes the common clonal origin of the diagnostic and relapse blast populations and suggests a stem cell origin of NOTCH1 mutations during the molecular pathogenesis of these tumors.     

Human cord blood conditioned medium enhances leukemia colony formation in vitro

Childhood T-cell acute lymphoblastic leukemia (T-ALL) is one of the most common childhood cancers. Recently, we observed that pre-conditioning sub-lethally irradiated immunodeficient mice with human cord blood mononuclear cells facilitates in these mice high level engraftment of primary T-ALL cells obtained from patients. Here we report that human cord blood cells secrete a factor(s) which markedly enhances in vitro both colony number and burst size of the T-ALL clonogenic progenitors from patients. The enhancing activity does not correspond to IL-2, IL-15, nor to several other cytokines implicated in T cell proliferation/activation. Thus, it is possible cord blood may secrete an as yet unidentified factor(s) acting on leukemia clonogenic progenitors of T-ALL. Collectively, these studies should prove invaluable in addressing the growth properties of primary T-ALL cells from patients.     

FLAG方案和IA方案对P-gp阳性和阴性急性髓细胞白血病细胞的作用

 目的　探讨FLAG和IA方案对P-gp阳性和阴性急性髓细胞白血病（AML）细胞增生抑制作用的优劣及其机制。方法　流式细胞仪检测K562和K562／A02细胞的P-gp 表达,MTT法检测FLAG和IA方案对K562和K562／A02细胞的增生抑制作用,高效液相色谱法检测细胞内Ara-CTP、Ara-C水平,实时定量PCR检测细胞hENT1基因表达。结果　K562 和K562／A02细胞的P-gp阳性率分别为（1.32±0.24）%和（97.66±3.77）%,两种化疗方案对细胞的P-gp表达无影响。FLAG方案对K562细胞的增生抑制作用较IA方案差[（73.17±13.20）%对（84.41±9.33）%,P <0.05],而对K562／A02细胞的增生抑制作用优于IA方案[（70.55±11.32）%对（48.46±12.81）%,P <0.01]。FLAG方案作用时AML细胞内Ara-CTP、Ara-C水平及人平衡核苷载体（hENT1）基因表达均较IA方案作用时升高（P <0.05）。结论　P-gp阳性AML细胞对FLAG方案较IA方案更敏感。氟达拉滨对Ara-C的生化调节可能是其主要机制。     

阿糖胞苷增强白血病细胞B7分子表达及促进双功能抗体对靶细胞的杀伤

目的：研究阿糖胞苷(cytarabine,AraC)对白血病细胞共刺激分子B7表达的影响,以及联合双功能抗体antiCD3/antiPgp介导T细胞对耐药白血病细胞的杀伤作用。方法：应用流式细胞术检测白血病细胞株K562和多药耐药白血病细胞株K562/A02细胞经AraC刺激不同时间后B71、B72分子的表达,RTPCR方法检测B71mRNA、B72 mRNA的表达,MTT法检测经AraC刺激的K562和K562/A02细胞对T淋巴细胞增殖的影响。CytoTox 96非放射性细胞毒性分析检测AraC联合antiCD3/antiPgp微型双功能抗体对人外周血淋巴细胞杀伤K562和K562/A02靶细胞的影响。结果：经AraC刺激的K562和K562/A02细胞B71、B72分子的表达较对照组明显升高;MTT结果显示,经AraC刺激的K562和K562/A02细胞能促进T淋巴细胞增殖;AraC联合antiCD3/antiPgp双功能抗体在0.39∶1~25∶1效靶比范围内,随着效靶比的升高,介导T淋巴细胞对K562和K562/A02细胞的杀伤率随之提高,对高表达Pgp的耐药K562/A02细胞尤为明显。结论：AraC可上调白血病细胞B7分子的表达,从而增强antiCD3/antiPgp双功能抗体介导的T细胞对靶细胞的体外杀伤作用。     

Chromosomal aberrations in 17p predict in vitro drug resistance and short overall survival in acute myeloid leukemia

Chromosomal aberrations are important prognostic parameters in acute myeloid leukemia (AML). Indicators of poor prognosis include del(5q)/-5, del(7q)/-7, abnormal 3q or complex karyotype. In recent years, it has become clear that aberrations in 17p represent one of the indicators of poor prognosis in haematological malignancies. In AML, deletions in 17p have been shown to indicate a dismal prognosis; genetic aberrations in 9p have also been discussed as influencing long-term survival in AML. In this study, we correlated genetic abnormalities in chromosomes 9 and 17 in patients with de novo AML to in vitro cytotoxicity of conventional anti-leukemic drugs, and long-term overall survival. Blast cells were isolated from 387 patients diagnosed with AML. Chromosomal analysis was successful in 336 cases. All samples were tested for in vitro cytotoxicity against fludarabine, amsacrine, mitoxantrone, etoposide, daunorubicin and Ara-C after being cultured for 4 days, using an ATP assay. Among the 336 patients, five main groups were identified. Abnormal chromosome 17 (n = 22), abnormal 9p (n = 13), monosomy 7 or deletion 7q (n = 35), complex karyotype (n = 52) and normal karyotype (n = 132). Patients with abnormalities of chromosome 17 showed significantly greater resistance to all drugs tested and significantly shorter overall survival compared with patients with normal and complex karyotypes (p = 0.0001 and 0.041, respectively). All patients with abnormalities of chromosome 17 died within 11 months of diagnosis. A tendency towards shorter overall survival and greater drug resistance was also noted when comparing chromosome 17 abnormalities with del(7q)/-7, but the differences did not reach statistical significance. Patients with abnormal 9p showed significantly shorter overall survival but did not differ significantly as regards in vitro drug resistance compared with patients presenting with a normal karyotype. Chromosomal abnormalities affecting the p53 pathway have a significant impact on cytostatic drug resistance and survival in AML. Developing new drugs targeting the p53 pathway could be a way to improve treatment of AML.     

Immunologic and clinicopathologic features of common acute lymphoblastic leukemia antigen-positive childhood T-cell leukemia. A Pediatric Oncology Group Study

The immunologic and clinicopathologic features of common acute lymphoblastic leukemia antigen (CALLA)-positive and CALLA-negative T-acute lymphoblastic leukemia (ALL) and of CALLA-positive non-T, non-B ALL (common ALL) of childhood were compared. Twenty-seven percent of children with T-ALL had blasts that expressed CALLA. This expression was not associated with a significantly different incidence of expression of sheep erythrocyte-rosette receptors, glucocorticoid receptors, peanut agglutinin receptors, or T-cell antigens. CALLA-positive T-cell blasts were more likely to express a p24 leukemia-associated antigen (CD9, 50% versus 8%) and Ia antigens (39% versus 8%) than were CALLA-negative blasts. Patients with CALLA-positive and CALLA-negative T-ALL had similar clinicopathologic features at diagnosis. In contrast, compared to patients with common ALL, patients with CALLA-positive T-ALL were older, had higher leukocyte counts, and an increased incidence of splenomegaly, lymphadenopathy and mediastinal mass, similar to patients with CALLA-negative T-ALL. Patients with CALLA-positive T-ALL were more likely to achieve a complete remission (95% versus 83%, P = 0.055) and tended to have an increased duration of event-free survival (P = 0.07) than did patients with CALLA-negative T-ALL. The expression of T-cell antigens is more important than the expression of CALLA in defining biologically similar subgroups of childhood ALL. Preliminary evidence suggests that within T-ALL the expression of CALLA may be prognostically important.     

Verapamil preferentially potentiates in-vitro cytotoxicity of vincristine on malignant lymphoid cells.

Verapamil has been shown to overcome acquired drug resistance to vincristine in P388 leukemia both in vitro and in vivo. To study the selectivity of this action, the effect of addition of verapamil on the cytotoxicity of vincristine was studied using lymphocytes from eight patients with chronic lymphocytic leukemia (CLL), lymphoblasts from a T-acute lymphoblastic leukemia (T-ALL) cell line (GM 3639), and peripheral blood lymphocytes (PBL) from eight normal healthy volunteers. Using the differential staining cytotoxicity (DiSC) assay, we demonstrated that verapamil at 1 microM concentration potentiated the in-vitro cytotoxicity of vincristine on CLL and GM 3639 cells in concentrations of 0.04-0.25 micrograms/l. There was however, no enhancement of cytotoxicity noted against the control PBL. The data demonstrate that verapamil preferentially enhances the in-vitro cytotoxicity of vincristine on CLL and GM 3639 cells but no enhancement of cytotoxicity is seen against PBL.     

免疫分型对急性白血病诊断及预后诊断的意义

目的探讨免疫分型对急性白血病的分型诊断及预后诊断的价值。方法采用碱性磷酸酶抗碱性磷酸酶复合物(APAAP)法检测53例急性白血病患者的免疫分型。结果 免疫分型诊断急性髓系白血病(AML)27例,T淋巴细胞白血病(T-ALL)8例,B淋巴细胞白血病(B-ALL)10例,混合型自血病(ABL)6例,未分化型自血病(AUL)2例。T-ALL CD7阳性最常见,B-ALL CD19阳性最常见。AML中抗原表达依次为CD33>CD13>CD14>CD15,CD34/CD34/HLA-DR表达阳性率为64.2％。AML中阳性病例完全缓解率低于阴性病例。ABL及AUL治疗效果差。结论 白血病免疫分型可提高确诊率,并为预后判断提供依据。