Plasminogen activator in acute myeloid leukaemic marrows: u-PA in contrast to t-PA in normal marrow

Leukaemic and normal bone marrow samples were compared in terms of their content of the fibrinolytic agents, tissue plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA) and their inhibitors, plasminogen activator inhibitors 1 and 2 (PAI-1 and PAI-2). Normal marrow contained t-PA as the principal plasminogen activator, whereas in leukaemic marrow samples u-PA was the predominant activator. Both normal and leukaemic marrows contained PAI-1 in similar amounts, but whereas normal marrow contained significant amounts of PAI-2 the leukaemic marrows contained very little. Plasminogen activators were present in uncomplexed, active forms and plasmin–α₂-antiplasmin complexes were generated locally more prominently in leukaemic marrows. u-PA associated with blast cells may contribute to the severe forms of haemorrhage sometimes occurring in myeloid types of leukaemia.     

Expression of multidrug resistance P-glycoprotein in myeloid progenitor cells of different phenotype: comparison between normal bone marrow cells and leukaemia cells

We examined the multidrug resistant P-glycoprotein (P-gp) on normal bone marrow (BM) cells and acute myeloid leukaemia (AML) cells, using newly devised flow cytometric multi-parameter analysis with CD33, CD34 and MRK16 monoclonal antibodies. In both normal BM cells and AML cells, CD34⁺CD33⁻ cells expressed P-gp strongly, CD34⁺CD33⁺ cells moderately, and CD34⁻CD33⁺ cells weakly. Acute promyelocytic leukaemia, mainly expressing CD34⁻CD33⁺ but not CD34⁺CD33⁻ at diagnosis, expressed less P-gp. P-gp expression of AML cells at diagnosis was increased as compared with normal cells of the same phenotype. P-gp expression was more increased in relapsed cases, especially in immature subpopulations.     

Expression of urokinase-type plasminogen activator receptor and plasminogen activator inhibitor-1 in gastric cancer

In gastric cancer, the urokinase-type plasminogen activator (uPA) system plays important roles in invasion and metastasis, processes which entail proteolysis and adhesion. Both the urokinasetype plasminogen activator receptor (uPAR) and the plasminogen activator inhibitor-1 (PAI-1) are thought to be important factors in this system. To clarify the relationship between these two factors and gastric cancer invasiveness, we evaluated the expression of uPAR and PAI-1 in 91 cases of gastric cancer by immunohistochemistry and in situ hybridization. Urokinase-type plasminogen activator receptor-mRNA, PAI-1-mRNA, uPAR and PAI-1 protein were diffusely distributed in the cytoplasm of the cancer cells and concentrated at invasive foci. Urokinase-type plasminogen activator receptor protein expression correlated with lymphatic, venous invasion (P<.01) and lymph node metastasis (P<0.05); uPAR-mRNA expression correlated with lymphatic, venous invasion and lymph node metastasis (P<0.05). Plasminogen activator inhibitor-1 protein expression correlated with lymphatic, venous invasion, lymph node metastasis and depth of invasion (P<0.01); PAI-1-mRNA expression was linked to lymphatic, venous invasion (P<0.01), lymph node metastasis and depth of invasion (P<0.05). This suggests that the proteolytic activity of uPAR and the cellular motility of PAI-1 in gastric cancer cells may determine penetration of lymphatic and blood vessels, whereby lymph node metastasis may be promoted and that the promotion of cellular motility by PAI-1 may influence the depth of cancer invasion.     

Non-Random and Random Chromosomal Abnormalities in Transformed Chronic Granulocytic Leukaemia

Chromosome abnormalities, identified using a banding technique and additional to the Ph, are reported in 10 consecutive cases of transformed chronic granulocytic leukaemia. In most of the cases the abnormalities were non random. In 2 cases serial studies were performed and additional abnormalities found, antedating transformation by one week and two months respectively. In 2 others the Ph status had been established during the chronic phase of the disease. In the remaining cases the first chromosome analysis was performed at the time of transformation.     

类风湿关节炎中尿激酶型纤溶酶原激活物及其受体蛋白和基因的表达

目的　检测尿激酶型纤溶酶原激活物 (uPA)及其受体 (uPAR)蛋白和mRNA在类风湿关节炎 (RA)的表达 ,探讨uPA、uPAR基因在RA细胞外基质降解中的作用。方法　采用免疫组化和cDNA mRNA原位分子杂交技术分别检测了 2 4例RA、18例骨关节炎 (OA)和 6例正常滑膜组织中uPA、uPAR蛋白和mRNA的分布及表达情况。结果　 2 4例RA滑膜组织均呈uPA、uPAR蛋白和mRNA的阳性表达 ,uPA、uPAR蛋白的强阳性率高于mRNA。uPA、uPAR蛋白和mRNA阳性信号主要分布在RA滑膜衬里细胞、滑膜下层单核细胞、巨噬细胞样细胞及血管内皮细胞 ;18例OA滑膜组织中 ,uPA、uPAR蛋白和mRNA的表达部位类似于RA ,但阳性率、阳性程度及分布范围均明显低于RA滑膜组织 ,两组之间蛋白和mRNA表达的差异均有显著性 (P <0 0 1或P <0 0 0 1)。 6例正常滑膜组织呈阴性反应。结论　RA滑膜组织存在高水平uPA、uPAR蛋白和mRNA的表达 ,提示在RA的发生发展过程中 ,uPA和uPAR基因起着重要作用 ;RA和OA中uPA、uPAR基因表达水平的差异 ,可能与这两种疾病软骨和骨基质降解的程度及进程等临床表现密切相关     

The role of gemtuzumab ozogamicin in acute leukaemia therapy

Gemtuzumab ozogamicin (GO) is an immunoconjugate that binds to CD33 on the surface of acute myeloid leukaemia (AML) blasts and, after internalisation, releases a cytotoxic drug, calicheamicin. GO is approved by the US Food and Drug Administration for the treatment of CD33-positive AML at first relapse in patients 60 years and older who are not candidates for other cytotoxic therapy. GO as a single agent has low antileukaemic activity. When given to patients meeting the criteria noted above, it produces a complete response (CR) rate of only 12%, with another 12% achieving CR with inadequate platelet recovery (CRp). The median survival of patients treated with GO monotherapy is 11.2 months. GO therapy at 9 mg/m(2) is complicated with hepatic veno-occlusive disease in 5-10% of patients, particularly prior to or following stem cell transplantation. GO at lower doses combined with chemotherapy as induction or postremission therapy is promising, however, and phase III trials are ongoing. GO is probably most active in acute promyelocytic leukaemia (APL). It is used for induction regimens in high-risk APL and for the elimination of minimal residual APL. Case reports suggest that GO also has activity in CD33-positive acute lymphoblastic leukaemia. In conclusion, single agent GO can induce responses in patients with CD33-positive AML in first recurrence. The future of GO is its use in combination with other cytotoxic agents. Ongoing clinical trials may better define the role of GO combinations, particularly in untreated AML.     

The future role of monoclonal antibody therapy in childhood acute leukaemias

Leukaemia is the single most common childhood malignancy. With modern treatment regimens, survival in acute lymphoblastic leukaemia (ALL) approaches 90%. Only about 70% of children with acute myeloid leukaemia (AML) achieve long term survival. Patients who relapse have a dismal prognosis. Novel therapeutic approaches are needed to improve treatment outcomes in newly-diagnosed patients with a poor prognosis and for patients with relapsed/refractory disease that have limited treatment options. One promising approach in treating haematological malignancies has been the use of monoclonal antibodies to target cell surface antigens expressed on malignant cells. Most success with monoclonal antibody therapy in the treatment of haematological malignancies has come in the setting of adult B-cell non-Hodgkin lymphoma with the addition of the anti-CD20 monoclonal antibody rituximab to standard treatment regimens. In order to further advance treatment of haematological malignancies, novel monoclonal antibodies continue to be developed that target a variety of cell surface antigens. Several antibodies continue to be investigated in childhood leukaemias. This review will discuss the development of monoclonal antibodies that target a variety of cell surface antigens for the treatment of childhood ALL and the use of the anti-CD33 antibody gemtuzumab ozogamicin in the treatment of childhood AML.     

P-glycoprotein and multidrug resistance-associated protein, but not lung resistance protein, lower the intracellular daunorubicin accumulation in acute myeloid leukaemic cells

The in vitro intracellular daunorubicin accumulation (IDA) of blast cells from 69 patients with newly diagnosed acute myeloid leukaemia (AML) was correlated with the expression and functional activity of the multidrug resistance (MDR) proteins, P-glycoprotein (Pgp), multidrug resistance-associated protein (MRP) and lung-resistance protein (LRP). An inverse and significant association was found between IDA and Pgp-related efflux activity (r = -0.31, P = 0.01) and also MRP (r = -0.25, P = 0.04) but not with LRP (r = -0.13, P = 0.28). Coexpression of the MDR proteins had an additive effect in further lowering of IDA levels, suggesting that the clinical MDR phenotype is dependent on the sum of multiple MDR factors available to the leukaemic cell. Thus, the median IDA of leukaemic cells without any MDR proteins was significantly higher than that of blasts carrying two MDR proteins (0.466 vs. 0.296, P = 0.046). Seven patients with no expression of Pgp, MRP and LRP still had low IDA levels, suggesting the presence of efflux MDR mechanisms other than those studied. The relation of IDA to clinical parameters known to be associated with poor prognosis, such as age, secondary AML, karyotype, peripheral blood blast and CD34 counts, was also studied, but no significance was found on multifactorial analysis. There was a non-significant trend for earlier relapse in patients with low IDA levels (leukaemia-free survival of 16.3 months compared with 21.1 months in patients with high IDA levels). Our data suggest that, while the IDA assay is a quick and relatively easy test for the combined efflux MDR phenotype, it is unable to detect other MDR mechanisms, such as LRP, which may be important to the clinical outcome of patients with AML.     

Therapy-related acute myeloid leukaemia after successful therapy for acute promyelocytic leukaemia with t(15;17): a report of two cases and a review of the literature

We describe two patients with positive t(15;17) acute promyelocytic leukaemia (APL) that developed into a therapy-related myelodysplasia 2-2.5 years after complete remission (CR) and then evolved into therapy-related acute myeloid leukaemia (t-AML). Both patients received anthracyclines as potential leukaemogenic drugs. In both cases, cytogenetic changes usually occurring after use of alkylating agents were noticed: monosomy 7 associated with monosomy 5 or 5q- chromosome. A review of the literature on t-AML occurring after successful therapy for APL showed only one report similar to these two cases. These observations suggest that anthracyclines can cause t-AML similar to that induced by alkylating agents.     

Molecular cytogenetics of childhood acute myelogenous leukaemias

Abstract: Chromosome abnormalities of childhood acute myeloblastic leukaemia, observed at least in 70–80% of cases, are presently recognized as important parameters for diagnostic, prognostic and follow-up purposes. These abnormalities are numerical, structural or both numerical and structural. They are also classified in “primary” abnormalities, usually more or less related with one subtype of leukaemia, and “secondary” abnormalities thought to appear in a second time. Chromosome abnormalities of childhood acute myeloblastic leukaemia (AML) are not basically qualitatively different from those of adult AML. The main difference lies in the incidence of the various types of abnormalities, and these differences appear to be more marked for age extremes such as infants and elderly patients. In total, 3 common abnormalities are more frequently observed in childhood than in adult AML: t(8;21) in AML-M2, monosomy 7 in AML-M4, der(11q) in AML-M5. In addition, molecular rearrangements associated with chromosomal abnormalities are dependent on the type of rearrangement and not on age. As in adult AML, the prognostic value of chromosome abnormalities has been diversely evaluated; some anomalies seem to be related to a shorter survival than others independent of the various therapeutic protocols used. In the present work, chromosome abnormalities of childhood AML have been reviewed according to cytologic subtypes as well as to some clinical settings. Special attention has been paid to abnormalities frequently or exclusively encountered in children.     

Quantitative expression of thrombopoietin receptor on leukaemia cells from patients with acute myeloid leukaemia and acute lymphoblastic leukaemia

Using a non-isotopic ligand binding assay, we quantitatively examined the amount of human thrombopoietin (TPO) receptor (TPO-R) on leukaemia cells from 128 patients with acute myeloid leukaemia (AML) or acute lymphoblastic leukaemia (ALL). The TPO-R was expressed in 53 (47%) of 114 AML cases, and an in vitro treatment with TPO led to proliferation (stimulation index >1.5) of leukaemia cells in 13 (20%) of 66 AML cases examined. The TPO levels had no relation to the FAB classification except for FAB-M7 AML. All five FAB-M7 cases expressed TPO-R, and one of three FAB-M7 examined showed in vitro proliferative response to TPO. Although there was no significant correlation ( r  = 0.3125) between the amount of TPO-R and the proliferative response, all of the AML cases which showed the in vitro response had TPO-R expression. There was no relationship between TPO-R amount and CD phenotypes, or the amount of granulocyte-colony stimulating factor (G-CSF) receptor. TPO-R was also expressed in two (14%) of 14 cases of ALL, and only these two cases had in vitro proliferative response to TPO. One had only lymphoid antigens, and the other had both lymphoid and myeloid antigens. Our results suggest that some leukaemia cells express functionally active TPO-R.     

Expression of the leptin receptor in human leukaemic blast cells

The leptin receptor is a member of the cytokine receptor superfamily, and is expressed in CD34 haemopoietic stem cells. We examined expression of the leptin receptor in fresh human leukaemia cells. Northern blot analysis showed the leptin receptor was expressed in leukaemic cells from patients with acute myeloblastic leukaemia, acute lymphoblastic leukaemia and chronic myeloid leukaemia (CML). In CML, higher expression was observed in blast crisis than in chronic phase. The expression of leptin receptor decreased during in vitro differentiation of leukaemic blast cells. It appeared that expression of the leptin receptor was associated with immature leukaemic blast cells. Our findings may indicate the possibility that leptin has some role in leukaemia.     

尿激酶型纤溶酶原激活物受体在人脑胶质瘤中的表达及临床意义

应用流式细胞仪定量检测正常脑组织 (3例 )和胶质瘤 (32例 )标本中尿激酶型纤溶酶原激活物受体(u- PAR)含量 ,并探讨 u- PAR在人脑胶质瘤中的表达及其与临床各生物学参数的关系。结果显示 :u- PAR在人脑胶质瘤中的表达与病理分级呈显著正相关 (r=0 .83) ,而与病人性别、年龄、肿瘤部位、瘤体大小等因素无关。提示 u- PAR可作为判断人脑胶质瘤恶性程度和浸润潜能的一项参考指标。     

u-PAR在人脑胶质瘤中的表达及意义

目的探讨尿激酶型纤溶酶原激活物受体（u-PAR）在人脑胶质瘤中的表达及其与临床病理分级的关系。方法应用流式细胞仪定量检测35例人脑胶质瘤标本中u-PAR水平,其中Ⅰ级8例,Ⅱ级9例,Ⅲ级9例,Ⅳ级6例,正常脑组织3例,应用直接染色法。结果u-PAR在人脑胶质瘤中的表达与病理分级相关,Ⅲ、Ⅳ级与Ⅰ、Ⅱ级和正常脑组织比较有高度统计学差异（P〈0.01）。结论u-PAR表达与人脑胶质瘤病理分级相关,可作为判断其恶性程度和浸润性能的指标。     

Chromosomes, Auer rods and prognosis in acute myeloid leukaemia

We have analysed survival time and complete remission (CR) rate after induction treatment including cytosine arabinoside and an anthracycline antibiotic in 94 patients with acute myeloid leukaemia, comparing the results in four different groups according to the presence or absence of Auer rods and the presence (AN/AA) or absence (NN) of abnormal cytogenetic clones at diagnosis. The finding of Auer rods was a positive prognostic factor with respect to CR rate (p less than 0.02) and survival time (p less than 0.02) irrespective of the cytogenetic pattern. The AN/AA pattern was associated with lower CR rate (p less than 0.05) and 6-months survival (p = 0.05) in the 49 Auer rod-negative patients. In the 45 patients with Auer rods, no significant differences in CR rate or survival were seen between AN/AA and NN patients. We conclude that the negative prognostic impact of chromosome abnormalities in acute myeloid leukaemia might be restricted to Auer rod-negative disease.     

Possibilities for tailored and targeted therapy in paediatric acute myeloid leukaemia

The clinical outcome of acute myeloid leukaemia (AML) in children has improved considerably using intensive chemotherapy and/or stem cell transplantation. This leads to cure in 50-70% of patients, and also results in significant morbidity and mortality. Hence, we need other ways to improve the cure rate. This review discusses possibilities for tailored therapy, reviewing in vitro cellular drug sensitivity data. The results provide suggestions regarding the adaptation of clinical protocols in certain AML subgroups, although further clinical studies will show whether this is effective. Secondly, we review type 1 genetic abnormalities (such as receptor tyrosine kinase mutations) that result in enhanced survival and proliferation of leukaemic cells, which can be detected in approximately 50% of paediatric AML samples, and are non-randomly associated with French-American-British type and cytogenetic subgroups. FLT3 internal tandem duplication is associated with poor clinical outcome, and may be used for risk-group stratification. The first results with small molecule inhibitors in adult AML do not suggest their use in children as yet. International collaboration is needed to further improve outcome by developing treatment protocols for subgroups of paediatric AML.     

Influenza A (H1N1) virus induced long-term remission in a refractory acute myeloid leukaemia

There have been reports of haematological cancer patients achieving spontaneous remission after being infected with the influenza A or SARS-COV-2 virus. Here, we present the first case of long-term complete remission (CR) induced by influenza A (IAV, H1N1 subtype) in a refractory AML patient and have functionally validated this finding in two different animal disease models. We observed a significant increase in the proportion of helper T cells in the patient after IAV infection. The levels of cytokines, including IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ and TNF-α, were higher in IAV-infected patients compared with control groups. These findings indicate that the anti-tumour effects induced by IAV are closely related to the modification of the immune response. Our study provides new evidence of the anti-tumour effects of IAV from a clinical practice perspective.     

Desferioxamine increases iron depletion and apoptosis induced by ara-C of human myeloid leukaemic cells

We investigated whether changes in iron metabolism and the transferrin receptor (TRF-R) expression were involved in the antileukaemic effects of arabinoside cytosine (ara-C). Treatment with 100 n M ara-C for 48 h reduced thymidine uptake and increased the surface expression of the TRF-R on leukaemic blasts derived from 13/16 (81%) patients and on the HL-60 and U-937 cell lines. Whereas intracellular non-haem iron was strongly depleted 24 h after ara-C addition, TRF-R up-regulation and recovery of intracellular non-haem iron concentration occurred together after a longer exposure of the cultured cells to the drug. Since iron is an essential regulator of cell proliferation we have evaluated the effects of the combination between ara-C and the iron chelator desferioxamine (DSF) on the growth of HL-60 and U-937 cells. We found that desferioxamine strongly potentiated the effects of ara-C on leukaemic cell growth inhibition and apoptosis. This is the first report of a positive interaction between ara-C and an iron chelator in terms of antileukaemic effects.     

The concept of leukaemic stem cells in acute myeloid leukaemia 25 years on: hitting a moving target

The concept of leukaemic stem cells (LSCs) was experimentally suggested 25 years ago through seminal data from John Dick's group, who showed that a small fraction of cells from acute myeloid leukaemia (AML) patients were able to be adoptively transferred into immunodeficient mice. The initial estimation of the frequency was 1:250 000 leukaemic cells, clearly indicating the difficulties ahead in translating knowledge on LSCs to the clinical setting. However, the field has steadily grown in interest, expanse and importance, concomitantly with the realisation of the molecular background for AML culminating in the sequencing of hundreds of AML genomes. The literature is now ripe with contributions describing how different molecular aberrations are more or less specific for LSCs, as well as reports showing selectivity in targeting LSCs in comparison to normal haematopoietic stem and progenitor cells. However, we argue here that these important data have not yet been fully realised within the clinical setting. In this clinically focused review, we outline the difficulties in identifying and defining LSCs at the individual patient level, with special emphasis on intraclonal heterogeneity. In addition, we suggest areas of future focus in order to realise the concept as real-time benefit for AML patients.