Antisense RNA therapy for CML — An hypothesis

CML, a myeloproliferative clonal disorder of myeloid stem cells, is characterized by the consistent presence of a bcr - c-abl fusion gene which is formed as a rsult of a translocation of the c-abl gene from chromosome 9 to downstream of the bcr gene on chromosome 22 (ph'). Current approaches to the treatment of CML are chemotherapy (conventional or aggressive with immuno-modulators) and bone marrow transplantation (BMT). Neither of the abve treatment modalities results in long-term remission or cure. Hence, an alternative approach which aims at correcting the genetic defect should be considered. Taking advantage of the consistent abnormal presence of the bcr - c-abl gene in the treated and untreated CML patients at all stages, a gene therapy at the level of blocking mRNA might be considered. Such an antisense RNA therapy should include removal of patient's bone marrow, administration of the gene for constitutive expression of an antisense RNA for the bcr - c-abl fusion gene into the myeloid stem cells and reinjecting the engineered marrow into the patient. Such an approach, comparable to autologous BMT, will have the advantages of absence of graft rejection and possibility of 100% remission. The possible nature of the gene construct for such an antisense RNA therapy is discussed.     

Apoptosis and proliferation (PCNA labelling) in CML—a comparative immunohistological study on bone marrow biopsies following interferon and busulfan therapy

A comparative morphometric analysis was performed on smears and trephine biopsies of normal bone marrow and in chronic myelogenous leukaemia (CML) to assess the effects of therapy on apoptosis and cell proliferation. The in situ end-labelling (ISEL) technique was used for the demonstration of programmed cell death, in combination with the monoclonal antibody PG-M1 to identify macrophages. Cell proliferation was evaluated by employing the monoclonal antibody PC10 directed against proliferating cell nuclear antigen (PCNA). In CML (48 patients), significantly higher rates of apoptosis were observed than in normal bone marrow (smears, frozen sections, and paraffin-embedded samples) of 15 patients. In contrast, the PCNA labelling index of CML was not different from controls. In bone marrow tissue derived from CML patients, about 36 per cent of apoptotic bodies were ingested with CD68-positive macrophages. Study of the histotopographical distribution of labelled cells revealed that in CML, in contrast to the normal bone marrow, programmed cell death and PCNA activity were concentrated along the paratrabecular generation zone. In 28 patients with CML treated with interferon (IFN), sequential trephine biopsies displayed a significant enhancement of apoptosis which was associated with a decrease in PCNA reactivity. In contrast to this finding, no such alterations could be observed in 24 patients who received busulfan (BU) monotherapy. This study furthers the understanding of cell kinetics in CML. IFN therapy induces apoptosis and suppresses cell proliferation. The rate of programmed cell death prior to therapy and the extent of IFN-triggered apoptosis exert a significant predictive impact on survival. In this study, ISEL-positive (apoptotic) cells and bodies do not correspond to unscheduled cell repair as detected by PCNA immunoreactivity. © 1997 John Wiley & Sons, Ltd.     

Megakaryocytes carry the fused bcr-abl gene in chronic myeloid leukaemia: a fluorescence in situ hybridization analysis from bone marrow biopsies

Histological examination of bone marrow biopsies shows that about one-third of chronic myeloid leukaemia (CML) patients exhibit an increase of megakaryocytes. The megakaryocytic predominance may be so striking that differentiation from other chronic myeloproliferative disorders (CMPD) may be difficult in some CML patients. Megakaryocytes in CML are clonal as demonstrated by loss of glucose-6-phosphate dehydrogenase isoenzymes. The Ph translocation, fusing the abl and bcr genes on chromosomes 9 and 22, however, obviously occurs as a second step in tumour development. So far, the Ph translocation has not been assigned explicitly to megakaryocytes. The question is whether the megakaryocytic cell lineage could harbour the bcr/abl fusion in those CML cases with striking proliferation of megakaryocytes but lack this genetic defect in cases with normal or decreased megakaryocyte counts. We therefore performed triple-colour fluorescence in situ hybridization (FISH) for portions of the bcr and abl genes flanking the breakpoint in CML in paraffin sections of CML cases with normal and with increased numbers of megakaryocytes. This method allows identification of the bcr/abl fusion in single, morphologically intact cells, whereas conventional cytogenetics requires lysis and thus destruction of the cell. Among the 21 CML patients examined by FISH, 10 were informative for bcr and abl genes and displayed distinct hybridization signals within nuclei of bone marrow cells. Besides the granulopoietic cells, megakaryocytes of all those patients (4 without and 6 with varying grades of megakaryocytic increase) displayed bcr/abl fusion signals indiciative of a Ph translocation. The lack of hybridization signals in the remaining 11 cases indicates that this technique is not of value diagnostically and should be reserved for scientific questions. Positive controls consisted of conventional chromosome preparations from bone marrow aspirates demonstrating the Ph chromosome in all patients examined, and negative controls of paraffin sections of bone marrow biopsies from non-CML patients. These showed no fusion signals in bone marrow cells, including megakaryocytes, using FISH. Our results demonstrate clearly that not only the transforming event but also the Ph translocation leading to the bcr/abl fusion happens prior to the differentiation of the pluripotent stem cell into different myeloid lineages. The megakaryocytic proliferation evident in some CML cases is probably a consequence of the disease progress.     

Antisense RNA therapy for CML--an hypothesis

CML, a myeloproliferative clonal disorder of myeloid stem cells, is characterized by the consistent presence of a bcr-c-abl fusion gene which is formed as a result of a translocation of the c-abl gene from chromosome 9 to downstream of the bcr gene on chromosome 22 (ph'). Current approaches to the treatment of CML are chemotherapy (conventional or aggressive with immuno-modulators) and bone marrow transplantation (BMT). Neither of the above treatment modalities results in long-term remission or cure. Hence, an alternative approach which aims at correcting the genetic defect should be considered. Taking advantage of the consistent abnormal presence of the bcr-c-abl gene in the treated and untreated CML patients at all stages, a gene therapy at the level of blocking mRNA might be considered. Such an antisense RNA therapy should include removal of patient's bone marrow, administration of the gene for constitutive expression of an antisense RNA for the bcr-c-abl fusion gene into the myeloid stem cells and reinjecting the engineered marrow into the patient. Such an approach, comparable to autologous BMT, will have the advantages of absence of graft rejection and possibility of 100% remission. The possible nature of the gene construct for such an antisense RNA therapy is discussed.     

Fluorescent in situ hybridization diagnosis of extramedullary nodal blast crisis

The t(9;22)(q34;q11) translocation between bcr and abl genes plays a pivotal role in the pathogenesis and diagnosis of chronic myelogenous leukemia (CML). Fluorescence in situ hybridization (FISH) using specific DNA probes provides a useful and accurate way for the detection of bcr/abl fusion gene in single cell. Here, we report an unusual case of a patient with no prior hematologic disease who initially manifested lymphadenopathy. The lymph node findings were suspicious for T‐lineage lymphoblastic lymphoma, however, his blood and bone marrow at that time were in chronic phase of CML. This presented difficulty for accurate discrimination between CML blast crisis (BC) and non‐Hodgkin's lymphomas (NHLs). To discern where the extramedullary nodal malignancy originated from, we cytologically analyzed lymph node biopsies and bone marrow with FISH to detect bcr/abl fusion signals. Together with the morphology, immunohistochemistry, cytogenetics as well as molecular analysis, the patient was diagnosed as extramedullary T‐lymphoid BC of Ph+ CML. In conclusion, this case is unusual at three levels: first, extramedullary nodal BC as a presenting manifestation of CML is rare and the blasts are of precursor T lymphoblastic lineage, rather than the more common B‐cell lineage; second, this case suggests that extramedullary lymphoid nodal BC of CML can exist independently without the bone marrow developing into BC; and third, FISH analysis on the single neoplastic cell is an accurate way to confirm that the neoplasm is either extramedullary localized blasts of CML or genetically distinct neoplasm. Diagn. Cytopathol. 2013. © 2011 Wiley Periodicals, Inc.     

Short-term culturing influences the number of bcr/abl-fused cells detected by fluorescence in situ hybridisation in bone marrow aspirates of CML patients.

Fluorescence in situ hybridisation (FISH) has been proven as a helpful tool in diagnosis and monitoring of bcr/abl fusion in chronic myelogeneous leukaemia (CML). Since long-term cultures are known to decrease the number of bcr/abl-fused cells, it is questionable whether similar effects are detectable in short-term cultures, a technique often preceding FISH analysis. Therefore, we evaluated bone marrow aspirates of 10 CML patients at biopsy and after culturing for between 24 and 144 h by FISH. The percentage of bcr/abl-fused cells in FISH varied between 15 and 70% at biopsy. In samples with 15 and 30% of aberrant cells at biopsy, an increase of about 20% per day was seen within the first 48 h. In longer lasting cultures, the percentage of leukaemic cells then asymptotically approached a value of 60-70%. In patients with 38 and 50% of bcr/abl-fused cells at biopsy, an increase of about 20% could be detected in the first 24 h. Then 65-70% of the cells already bore the bcr/abl fusion, and the percentage of leukaemic cells was almost constant for longer lasting cultures up to 144 h. In patients with a percentage of about 70% before culturing, no increase in positive cells was detected. These results emphasize the impact of short-term culturing on the number of bcr/abl-fused cells. In particular, the importance for monitoring CML patients is obvious. Therefore the effect described should be taken into account in order to avoid misinterpretation and incorrect therapy decisions in CML patients.     

Growth kinetics and blast-colony forming cell binding capacity of stromal cells in various haematological malignancies.

Growth kinetics of bone marrow stromal layers from normal, AML, ALL and CML patients was studied. Significantly reduced time for confluency was observed in AML patients in complete remission, in CML patients in chronic phase, or CML patients after allogenic bone marrow transplantation. The functional capacity of these stromal layers did not differ: they all bound similar amounts of blast colony forming cells (BL-CFC) from normal bone marrow. The stromal layers from bone marrow transplanted patients varied in their BL-CFC binding capacity: two CML patients (10.5 and 49 months after transplantation) showed normal values, while two ALL patients (1.5 and 3 months, respectively, after transplantation) as well as one patient transplanted for CML (19.5 months after transplantation) showed significantly reduced BL-CFC binding capacity.     

Bone marrow changes in patients with hairy cell leukemia treated by recombinant alpha2-interferon

Bone marrow specimens from 21 patients with hairy cell leukemia (HCL) who were entered into a program to study the efficacy of treatment with recombinant alpha 2-interferon were evaluated. Patients were treated with the interferon, 2 X 10(6) U/m2 subcutaneously three times weekly, and were scheduled to undergo bone marrow aspiration and biopsy at study entry and after three (21 patients) and six (16 patients) months of treatment. Bone marrow samples after three months of treatment showed an overall decline in cellularity, from an average of 77 +/- 20 to 57 +/- 22 per cent, with a marked decrease in the percentage of neoplastic mass (from 87 +/- 9 to 59 +/- 24 per cent). The bone marrow changes were associated with significant improvement in hematologic values, including hemoglobin levels and granulocyte and platelet counts. The bone marrow changes and improved hematologic values remained stable with continuation of interferon therapy. However complete bone marrow remission did not occur in any of the patients after three or six months of interferon therapy. The HCL cell mass in more than 60 per cent of the patients remained at or above 50 per cent of the marrow cellularity and dropped to less than 25 per cent in 14 per cent of the patients. In all of the patients increased amounts of reticulin fibers were identified in the bone marrow prior to therapy, and 89 per cent of bone marrow aspirations failed (dry tap). The amounts of reticulin fibers remained increased in most of the patients (91 per cent), with a high incidence of dry taps (73 per cent), after therapy. Interferon therapy also changed the tartrate-resistant acid phosphatase(TRAP)-positive HCL cells to TRAP-negative, suggesting inhibition of activity and/or production of TRAP in HCL cells.     

Clinical and pathologic analysis of 16 cases of relapsed chronic myeloid leukemia after stem cell transplantation

Chronic myeloid leukemia (CML) is a myeloproliferative disease that originates in an abnormal pluripotent bone marrow stem cell and is characteristically associated with the Philadelphia chromosome and/or the bcr/abl fusion gene. Despite the exciting success of the bcr/abl tyrosine kinase-specific inhibitor imatinib for CML treatment, hematopoietic stem cell (bone marrow or peripheral blood stem cell) transplantation (HCT) remains the only "curative" approach for the majority of patients. Although HCT outcomes for patients with CML have improved considerably during the past 2 decades, relapse after HCT may occur. We analyzed the clinical and pathologic features of 16 cases of hematologically relapsed CML after HCT during a 5-year period at City of Hope National Medical Center, Duarte, CA. The results of our analysis showed that relapsed CML after HCT frequently manifested with advanced disease with a more aggressive clinical course and was often refractory to therapy. The frequency of acute leukemic transformation at time of relapse was largely associated with pre-HCT disease status and acquired secondary cytogenetic abnormalities. Disease mortality in patients with relapsed CML after HCT was closely associated with advanced disease and HCT-related complications.     

慢性粒细胞白血病和原发性骨髓纤维化患者bcr/abl融合基因表达及临床意义

目的探讨bcr/abl融合基因的表达水平在慢性粒细胞白血病(CML)和原发性骨髓纤维化(MF)患者的诊断、疗效及预后观察中的意义.方法采用荧光定量逆转录多聚酶链反应(RT-PCR)技术,对18例初、复治CML、7例MF患者的骨髓或外周血单个核细胞进行了bcr/abl融合基因检测,并对其中2例行异基因骨髓移植(allo-BMT)患者进行了短期随防.结果 13例慢性期(CP)CML,12例不同程度表达bcr/abl融合基因,占92.3%,3例加速期(AP),急变期(BC)CML,2例表达bcr/abl融合基因,占66.7%,2例患者allo-BMT后一年内未检出 bcr/abl融合基因,三者之间有非常显著差异P＜0.01;8例初诊患者WBC数及bcr/abl融合基因表达水平明显高于常规治疗组;7例MF患者有1例表达bcr/abl基因.结论 bcr/abl基因是CML发病的分子基础,定量检测bcr/abl融合基因对于CML的诊断、临床分型、疗效观察及预后判断有重要意义;MF患者可能与CML关系密切,对MF患者应进行跟踪观察.     

Studies of BCR and ABL gene rearrangements in chronic myelogenous leukemia patients by conventional and pulsed-field gel electrophoresis using gel inserts

Continual monitoring of the presence of the Philadelphia (Ph) chromosome in patients with chronic myelogenous leukemia (CML) is important for diagnosis as well as evaluation of therapy response of these patients. Because the Ph chromosome has been characterized molecularly to involve a reciprocal translocation between the ABL and BCR genes, there is an increasing interest in the use of molecular probes to detect chromosomal rearrangements in this disease. While rearrangements involving the bcr region of the BCR gene can be detected by conventional gel electrophoresis (CGE), detection of those involving ABL generally requires pulsed-field gel electrophoresis (PFGE). Currently, however, CGE and PFGE require different methods of cell preparation, with isolated DNA used in CGE and gel inserts containing whole cells used in PFGE. In this study, we show that the gel-insert method of DNA preparation can be adapted for use in CGE with slight modification of the gel-running conditions. The advantages of this method are demonstrated by studying both bcr and ABL rearrangements in bone marrow and peripheral blood samples of CML patients. Furthermore, we report a novel finding that chromosomal breakpoints in the ABL gene of CML patients occur predominantly between exons 1b and 1a.     

Neuropilin-1基因在CML骨髓基质细胞中的表达及其意义

目的　了解Neruophlin -1基因在慢性粒细胞白血病 (CML)骨髓基质细胞中的表达情况 .方法　收集 14例CML和 2 0例正常对照骨髓标本 ,分离单个核细胞 .进行体外长期培养 ,收集贴壁细胞 (骨髓基质细胞 ) .利用RT -PCR方法分析两组骨髓基质细胞中的cDNA ,了解Neuropilin -1基因表达情况 .结果　建立了CML和正常人骨髓基质细胞培养方法 ,CML骨髓基质细胞中的Neuropilin -1基因表达率 (50 % )明显低于正常对照 (85% ) (p <0 .0 5) .结论　参与调控骨髓基质细胞的Neuropilin -1基因可表达于大部分正常人和部分CML患者骨髓基质细胞中 ,Neuropilin -1基因在部分CML骨髓基质细胞中的表达缺失可能与其调节造血功能异常有关     

Molecular and clinical investigations in Philadelphia chromosome-negative chronic myelogenous leukemia

We performed molecular studies in five cases of Philadelphia (Ph) translocation-negative chronic myelogenous leukemia (CML). Among the five, one case showed a 7q - anomaly; the remaining four had normal karyotypes. The 5' or 3' breakpoint cluster region (bcr) DNA probes detected rearrangements in two of the five cases. The two cases with bcr rearrangement showed clinical and hematologic manifestations similar to those with Ph-positive CML; for example, basophilia in the peripheral blood and marked hepatosplenomegaly. On the other hand, the three Ph-negative CML cases without bcr rearrangement manifested somewhat different clinical manifestation; that is, they did not respond to busulfan therapy in the chronic phase. Our observations suggest a heterogeneity in Ph-negative CML with at least two subtypes: one with a rearranged bcr gene showing clinical and hematologic features akin to those of CML with a Ph translocation, and the other without such a rearrangement and with a somewhat different clinical feature. Furthermore, the present data point to the possibility of the existence of Ph-negative CML without bcr rearrangement.     

Osteoclast induction from bone marrow cells is due to pro-inflammatory mediators from macrophages exposed to polyethylene particles: a possible mechanism of osteolysis in failed THA

Polyethylene debris from joint replacements may be transported in synovial fluid and be phagocytosed by macrophages. The activation and migration of macrophages may play important roles in osteolysis and implant loosening. Tissues from the bone-implant interface do not always contain wear debris, which may mean that osteolysis may not require direct contact with wear debris. We hypothesized that the release of polyethylene debris from the implants induces macrophage activation in the joint space. Then the activated macrophages release humoral factors, such as inflammatory cytokines, into the joint fluid. These cytokines may be transported to the bone marrow tissues around the implants where they stimulate the differentiation of the bone marrow cells into osteoclasts. Finally, the activated osteoclasts resorb the surrounding bone. To test this hypothesis, macrophages were stimulated by polyethylene particles. The levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) were determined by enzyme-linked immunosorbent assay and were increased significantly. To test humoral interaction between macrophages and bone-marrow cells, a co-culture system was used in an in vitro model. With this system, two kinds of cells can be cultured together with humoral contact without the two cell types having to contact each other. We stimulated the macrophages with 5 microm of polyethylene particles and observed whether the bone marrow cells differentiated into the osteoclasts without contact with the macrophages. The numbers of osteoclasts were assessed using tartrate-resistant acid phosphatase (TRAP) staining. The numbers of TRAP-positive cells in the polyethylene particle-stimulated group were higher than in the control group. The ability of the TRAP-positive cells to resorb bone was confirmed by dentine pit formation assay. The results of this study support our hypothesis and suggest that one mechanism of osteolysis in failed joint arthroplasty is the more distant effects of pro-inflammatory cytokine release on osteoclast differentiation and/or activity.     

骨髓增殖性疾病Bcr／Abl融合基因的表达及其意义

目的：为探讨几种骨髓增殖性疾病bcr／abl 融合基因出现的频率及临床意义．方法：采用逆转录多聚酶键反应（RT－PCR）技术,研究了慢性粒细胞白血病（CML）,真性红细胞增多症（PV）,原发性血小板增多症（ET）,原发性骨髓纤维化（MF）bcr／abl基因的变化．结果：48例慢性期CML,43例呈现bcr／abl基因阳性,占90％,14例加速,急变期CML,6例出现bcr／abl基因,阳性率为43％,与慢性CML相比P＜0.01;10例PV出现1例bcr／abl基因阳性,占10％,6例ET中未发出bcr／abl基因．2例MF中发现1例bcr／abl基因阳性．结论：bcr／abl基因检测对于CML的临床分型有重要意义,bcr／abl阴性的CML预后差,而bcr／abl基因的阳性有助于初诊时的CML急变与急性非淋巴细胞白血病（AML）M2的鉴别和CML与慢性粒单细地白血病（CMML）的鉴别．在其它三种骨髓增殖性疾病中MF可能与CML关系最为密切,而ET关系较远,少数PV可能转化为CML．     

Regression of the Philadelphia chromosome (bcr/abl)-positive myelo- and megakaryopoiesis after Imatinib (STI571) therapy in chronic myelogenous leukemia (CML)

In chronic myeloid leukemia following therapy with Imatinib (STI571) hematologic and cytogenetic response is associated with conspicuous changes of bone marrow morphology. However, it is not known to which extent these alterations are accompanied by a loss of the bcr/abl translocation. To study regression of the leukemic cell population we recruited 14 patients lacking pretreatment. Therapy resulted in a reduction of CD61(+) megakaryopoiesis. Dwarf megakaryocytes characteristic for this disorder were replaced by large, normally appearing cells of this lineage. Morphometric analysis confirmed the significant decrease in the number of micromegakaryocytes and yielded planimetric parameters in keeping with normalization. Moreover, a fluorescence in-situ hybridization study in five patients of this cohort revealed that before therapy 70% of all myeloid cells exhibited the bcr/abl gene. Regarding megakaryopoiesis about 65% of the micromegakaryocytes displayed positive signals. Following treatment these bcr/abl(+) cell populations decreased significantly while the emerging large megakaryocytes lacked a proper labeling. Because cytogenetic response and reduction of atypical micromegakaryocytes are linked, this feature may be useful to monitor therapeutic efficacy.     

A cytogenetic and fluorescence in situ hybridization evaluation of interferon-alpha in the treatment of chronic myeloid leukemia

The effect of interferon-alpha (IFN) for chronic myeloid leukemia (CML) in the chronic phase (CP) was retrospectively evaluated in comparison with that of busulfan (BU) or hydroxyurea (HU) given alone. Among 107 patients diagnosed with CML between 1982 and 1997, 72 CP cases evaluable for long-term follow-up included 13 patients treated with BU alone, 18 with HU alone, and 41 with IFN-based therapy. Complete cytogenetic response (CCR) was achieved in 4/41 IFN cases (10%), and partial or minimal cytogenetic response occurred in 18/41 IFN cases (44%). In contrast, no cytogenetic response (NCR) was achieved in any BU or HU case. IFN treatment for 6 to 60 months was needed to achieve CCR. Overall survival curves revealed that the IFN group had significantly better survival than BU and HU groups (p=0.008 and 0.04, respectively). A significant correlation was found between karyotypic findings and fluorescence in situ hybridization (FISH) analyses in IFN-treated cases (r=0.739, p=0.0001). In some cases, however, the two methods showed discrepancy; BCR/ABL-positive cells represented only 20-75% of interphase bone marrow cells in NCR cases, although all metaphases examined were positive for the Philadelphia chromosome (Ph). A discrepancy was also seen in CCR cases; up to 22% of cells assessed were BCR/ABL-positive. These findings suggest that IFN is a useful therapy for CML in CP, and may have a suppressive effect on the CML clone even in NCR cases. The results also indicate that a combination of FISH and cytogenetic analyses may provide more detailed information for evaluating the efficacy of IFN than conventional cytogenetics alone.     

600例慢性粒细胞白血病的细胞遗传学分析

目的为了探讨我国慢性粒细胞白血病（慢粒）中Ｐｈ染色体的有关特点及其意义。方法染色体制备采用骨髓细胞直接法和／或短期培养法，应用Ｒ显带技术对６００例慢粒患者的细胞遗传学资料进行了回顾性分析。结果３０例（５％）为Ｐｈ（－），５７０例（９５％）为Ｐｈ（＋）；５３５例（９３．８％）有典型Ｐｈ易位，３４例（５．９％）有变异易位，包括简单变异易位和复杂变异易位各１３例（２．２％），隐匿Ｐｈ易位８例（１．４％）；５２６例（９２．２％）的Ｐｈ（＋）细胞为１００％，４４例（７．７％）经异基因骨髓移植、干扰素和脉冲羟基脲等治疗后有部分或全部细胞转为正常核型；５０．６％的慢粒急变患者有额外的染色体异常，其中以＋８、２Ｐｈ和ｉ（１７ｑ）最多见。结论染色体检查不但有助于慢粒的诊断和鉴别诊断，而且有助于预测急变、判断疗效和进行细胞遗传学分型