Advanced Stage Chronic Myelogenous Leukemia Research Articles

Prognostic Implications of Derivative Chromosome 9 Deletions in Patients with Advanced-Stage Chronic Myelogenous Leukemia.

Elucidation of cryptic BCR/ABL1 gene rearrangement is exceptionally important in the clinical diagnosis and prognosis of chronic myelogenous leukemia (CML). Previous reports indicated an adverse prognostic effect of atypical BCR/ABL1 gene rearrangements with submicroscopic ABL1-BCR deletions on derivative chromosome 9 [der(9)] in CML patients. Dual color dual fusion locus-specific BCR/ABL1 fluorescent in situ hybridization (FISH) analysis together with G-banding using trypsin and Giemsa (GTG banding) was performed in 489 patients at different stages of CML to investigate the spectrum of BCR/ABL1 gene rearrangements. Among the study group analyzed, a significantly higher frequency of BCR/ABL1 gene rearrangements that is consistent with der(9) deletion were observed in the blast crisis (BC) phase at 41.67%, followed by the accelerated phase (AP) at 36.84%, the imatinib mesylate (IM)-resistant chronic phase (CP) at 23.08%, and the lowest incidence was found in de novo CP at 16.61%. 1R1G1F (1 red, 1 green, 1 fusion) with concurrent loss of ABL1-BCR fusion gene on der(9) chromosome was the major signal pattern identified in each group. The results from the current study show that this unusual BCR/ABL1 gene rearrangement is one of the steering forces toward disease progression in CML. Patients in AP/BC of CML with der(9) deletion showed poor response to IM therapy; however, patients with der(9) deletion in the early phases of CML responded well to IM treatment. Therefore, the establishment of an atypical FISH signal pattern in CML is of paramount important because it is associated with adverse clinical prognostic implications in advanced stages of the disease.

Outcomes Following Bone Marrow Transplantation in Children With Accelerated Phase or Blast Crisis Chronic Myelogenous Leukemia in the Era of Tyrosine Kinase Inhibitors.

The management of chronic myelogenous leukemia (CML) in children changed dramatically with the introduction of tyrosine kinase inhibitors (TKIs). Unfortunately, outcomes for patients presenting in an advanced stage-accelerated phase or blast crisis CML-continues to be poor, requiring chemotherapy and allogeneic hematopoietic stem cell transplant (HSCT) to attempt cure. Integration of TKIs in the therapy of advanced CML is still an area of active investigation. There are little published data on TKI use in children with advanced stage CML. We performed a retrospective review of all children treated at our institution between January 1, 2010 and June 30, 2013, and identified 5 children, age 12 to 18 years, with advanced stage CML. All patients were treated with a TKI before HSCT and TKIs were restarted post-HSCT in 4/5 with a goal of continuing until 2 years posttransplant. At time of HSCT all were in a morphologic and cytogenetic remission; 1 patient had also achieved molecular remission. All patients are alive and in molecular remission at an average of 38 months (range, 14 to 51 mo) following transplant. Our experience indicates that TKIs are safe and well tolerated in children both pretransplant and posttransplant and may improve outcomes in this aggressive disease.

Identification of ILK as a novel therapeutic target for acute and chronic myeloid leukemia

Current treatment options as well as clinical efficacy are limited for chronic myelogenous leukemia (CML), Ph+ acute lymphoblastic leukemia (ALL), and acute myeloid leukemia (AML). In response to the pressing need for more efficacious treatment approaches and strategies to override drug resistance in advanced stage CML, Ph+ ALL, and AML, we investigated the effects of inhibition of ILK as a potentially novel and effective approach to treatment of these challenging malignancies. Using the small molecule ILK inhibitor, Cpd22, and ILK knockdown, we investigated the importance of ILK in the growth and viability of leukemia. Our results suggest that the ILK inhibition may be an effective treatment for CML, Ph+ ALL, and AML as a single therapy, with ILK expression levels positively correlating with the efficacy of ILK inhibition. The identification of ILK as a novel target for leukemia therapy warrants further investigation as a therapeutic approach that could be of potential clinical benefit in both acute and chronic myeloid leukemias.

Photochemical internalisation for the local delivery of chemotherapy

Current treatment options as well as clinical efficacy are limited for chronic myelogenous leukemia (CML), Ph+ acute lymphoblastic leukemia (ALL), and acute myeloid leukemia (AML). In response to the pressing need for more efficacious treatment approaches and strategies to override drug resistance in advanced stage CML, Ph+ ALL, and AML, we investigated the effects of inhibition of ILK as a potentially novel and effective approach to treatment of these challenging malignancies. Using the small molecule ILK inhibitor, Cpd22, and ILK knockdown, we investigated the importance of ILK in the growth and viability of leukemia. Our results suggest that the ILK inhibition may be an effective treatment for CML, Ph+ ALL, and AML as a single therapy, with ILK expression levels positively correlating with the efficacy of ILK inhibition. The identification of ILK as a novel target for leukemia therapy warrants further investigation as a therapeutic approach that could be of potential clinical benefit in both acute and chronic myeloid leukemias.

Dissecting the role of SALL4, a newly identified stem cell factor, in chronic myelogenous leukemia

Dissecting the role of SALL4, a newly identified stem cell factor, in chronic myelogenous leukemia

Disruption of the Bcr-Abl/Jak2/HSP90 Network Complex Leading to Induction of Apoptosis in Drug-Resistant CML Cells by a New Compound WP1193

In chronic myelogenous leukemia (CML), treatment of early stage disease has been significantly improved with the discovery of imatinib mesylate (IM, Gleevec), but with the progression of the disease, drug resistance develops which is due to mutation of the ATP binding site domain within the Bcr-Abl tyrosine kinase, the activation of Lyn kinase (a Src-related tyrosine kinase) and other mutations that produce a more aggressive disease. Thus, patients relapse and the disease progresses to blast crisis (BC) stage where survival is limited to only several months. No suitable drug treatment for BC is available, and the mechanism of drug resistance for BC is unclear. A new synthesized small molecule, WP1193, a caffeic acid derivative, induced apoptosis in all types of drug-resistant CML cells including IM-resistant T315I BCR-ABL+ cells, IM-resistant CML cells with up-regulated Lyn tyrosine kinase (K562-R) and cells from blast crisis CML patients. Treatment of BCR-ABL+ cells with WP1193 inhibited Janus kinase activities, leading to strong reduction of Bcr-Abl; this treatment also reduced STAT3 and pTyr 705 STAT3 protein levels. CML cell lines contain a large signaling network complex composed of Bcr-Abl, Jak2, HSP90 and its client proteins. HSP90 is a molecular chaperone that plays an important role in conformational maturation and stabilization of client proteins (Bcr- Abl, Jak2, STAT3, etc.), which are physically associated in the signaling network complex. This network complex (estimated to be between 2–5 million daltons) has been characterized by gel filtration column chromatography. This complex is disassembled by treatment of Bcr-Abl+ cells with WP1193 (10 μM for 3–6 h). Treatment of the cells with WP1193 also inhibited binding of STAT3 to its consensus DNA sequence and reduced levels of HSP90α transcripts, HSP90α protein and its client proteins, which include Bcr-Abl, Jak2 and Akt. WP1193 also reduced solid tumors in mice inoculated with IM-resistant K562-R cells, and inhibited leukemic effects caused by T315I BCR-ABL+ cells. These results indicate that disruption of the Bcr-Abl/Jak2/HSP90 network complex by WP1193 overcomes drug resistance in advanced stage CML cells. Since disruption of this network complex causes apoptosis induction in all IM-resistant and late stage CML patient cells tested so far, and since no significant toxicity was observed in short-term mouse experiments, WP1193 may have medical utility for the treatment of IM-resistant forms of CML and late stage CML where other drugs fail. One novel feature of WP1193 is its ability to reduce the activity of several important components of the network, namely Bcr-Abl, Jak2 and STAT3 activities and reduction of HSP90α, which then causes a high level of apoptosis in IM-resistant cells and late-stage CML cells.

Beneficial effects of combining nilotinib and imatinib in preclinical models of BCR-ABL+ leukemias

AbstractDrug resistance resulting from emergence of imatinib-resistant BCR-ABL point mutations is a significant problem in advanced-stage chronic myelogenous leukemia (CML). The BCR-ABL inhibitor, nilotinib (AMN107), is significantly more potent against BCR-ABL than imatinib, and is active against many imatinib-resistant BCR-ABL mutants. Phase 1/2 clinical trials show that nilotinib can induce remissions in patients who have previously failed imatinib, indicating that sequential therapy with these 2 agents has clinical value. However, simultaneous, rather than sequential, administration of 2 BCR-ABL kinase inhibitors is attractive for many reasons, including the theoretical possibility that this could reduce emergence of drug-resistant clones. Here, we show that exposure of a variety of BCR-ABL+ cell lines to imatinib and nilotinib results in additive or synergistic cytotoxicity, including testing of a large panel of cells expressing BCR-ABL point mutations causing resistance to imatinib in patients. Further, using a highly quantifiable bioluminescent in vivo model, drug combinations were at least additive in antileukemic activity, compared with each drug alone. These results suggest that despite binding to the same site in the same target kinase, the combination of imatinib and nilotinib is highly efficacious in these models, indicating that clinical testing of combinations of BCR-ABL kinase inhibitors is warranted.

Establishment and characterization of an STI571-resistant human myelogenous leukemia cell line, SR-1

The tyrosine kinase inhibitor STI571 is an effective agent for the treatment of chronic myelogenous leukemia (CML). However, a lack of response to STI571 or the recurrence of the disease after a transient initial response is usually seen in patients with advanced stage CML. We have established a novel STI571 (Gleevec/Glivec, imatinib mesylate)-resistant acute myelocytic leukemia cell line (SR-1) from an STI571-resistant blast crisis patient. By flow cytometry, the immunophenotype of SR-1 was found to be compatible with a myeloid lineage (CD13 +, CD33 +, HLA-DR +, anti-MPO +). Conventional cytogenetics showed a three-way reciprocal translocation involving 7p22, 9q34, and 22q11.2, i.e., a variant Philadelphia chromosome translocation. The BCR/ABL rearrangement was detected by fluorescence in situ hybridization and reverse transcriptase polymerase chain reaction. To determine the tumorigenicity of the SR-1 cell line in vivo, cells were injected subcutaneously into severe combined immunodeficiency mice. Four weeks later, tumors had grown and showed the same laboratory findings as in SR-1. Although STI571 resistance is a known treatment complication, in vivo STI571-resistant cell lines have not been fully established. We hope that our SR-1 cell line may be useful in molecular pathogenetic investigations of STI571-resistant CML.

The BCR/ABL transgene causes abnormal NK cell differentiation and can be found in circulating NK cells of advanced phase chronic myelogenous leukemia patients.

NK cells from the blood of chronic myelogenous leukemia (CML) patients are progressively decreased in number as the disease progresses from chronic phase to blast crisis. We hypothesize that BCR/ABL may be directly responsible by interfering with NK cell differentiation. CD34(+)HLA-DR(+) cells from CML patients were studied for their capacity to differentiate into NK cells. The NK cell cloning frequency was significantly decreased from CML CD34(+)HLA-DR(+) cells compared with cells from normal donors, yet CD34(+)HLA-DR(+) cells gave rise to BCR/ABL(+) NK cells in some patients. This finding prompted us to further investigate circulating NK cells from the blood of CML patients. CD56(+)CD3(-) NK cells were sorted from CML patients and examined by fluorescence in situ hybridization (FISH). In contrast to chronic phase CML, significant numbers of NK cells from advanced phase CML patients were BCR/ABL(+), whereas T cells were always BCR/ABL(-) regardless of the disease stage. To test the effects of BCR/ABL as the sole genetic abnormality, BCR/ABL was transduced into umbilical cord blood CD34(+) cells, and NK development was studied. p210-enhanced green fluorescence protein-transduced cells gave rise to significantly decreased numbers of NK cells compared with enhanced green fluorescence protein transduction alone. In addition, the extrinsic addition of BCR/ABL-transduced autologous CD34(+) cells suppressed the NK cell differentiation of normal umbilical cord blood CD34(+)CD38(-) cells. This study provides the first evidence that BCR/ABL is responsible for the altered differentiation of NK cells and that the NK cell lineage can be involved with the malignant clone in advanced stage CML.

Long-term follow-up of patients after related- and unrelated-donor bone marrow transplantation for chronic myelogenous leukemia

Between January 1983 and December 1997, 88 patients (36 female, 52 male, median age 37 years, range 19-57) with chronic myelogenous leukemia (CML) underwent allogeneic bone marrow transplantation (BMT) at the University Hospital of Vienna. Sixty patients were in chronic phase, 18 in accelerated phase, and ten in blast crisis. Marrow donors were HLA-identical siblings for 64 patients (BM 58, PBSC 6), 2-antigen-mismatched related donors (RD) for two, HLA-identical unrelated donors (URD) for 17, and 1-antigen-mismatched URD for five. The median time from diagnosis to BMT was 22 months (range 2-91), and 63 patients had received prior interferon (IFN)-alpha therapy, 46 (73%) for more than 6 months. Conditioning therapy consisted of cyclophosphamide (CY) and total body irradiation (TBI) in 71 patients and CY and busulfan (BU) in 16. One patient received etoposide and TBI. For graft-versus-host disease (GVHD) prophylaxis methotrexate (MTX) was given to 12 patients, MTX and cyclosporin A (CSA) to 67, CSA alone to four, and CSA and methylprednisolone to five. Durable engraftment was documented in 80 of 82 patients (98%). As of December 31, 1997, 52 patients (59%) were alive, 38 (58%) after sibling transplantation with a median observation time of 73 months and 14 (64%) after URD transplantation with a median observation time of 12 months. Probability of overall survival is 59%, for patients undergoing transplantation in chronic phase and 44% for patients undergoing transplantation in advanced stage CML. Probability of disease-free survival (DFS) after sibling and URD BMT is 55% and 59%, respectively. Ten patients (12%) experienced relapse of CML. Transplant-related mortality was 32% both after RD and after URD transplantation. Acute GVHD occurred in 53 of 80 evaluable patients (66%), consisting of grade III or IV in 14 patients (18%). Chronic GVHD developed in 40 of 63 eligible patients (63%), including extensive disease in 26 patients (41%). Thus, sibling and URD BMT offer high cure rates with acceptable toxicity to patients with CML.

Effect of retinoic acid and interferon alpha on granulocyte-macrophage colony forming cells in chronic myeloid leukemia: Increased inhibition by all- trans- and 13- cis-retinoic acids in advanced stage disease

Granulocyte-macrophage colony forming units (CFU-GM) from patients with advanced stage chronic myelogenous leukemia (CML), i.e. in blastic crisis (BC) or accelerated phase (AP), were inhibited by all- trans-retinoic acid (tRA) approximately 1000-fold more potently than those from chronic phase (CP) CML patients (median ic 50 = 10 −9 M tRA for six CML-AP/BC cases vs > 10 −6 M tRA for seven CML-CP cases). A similar activity pattern was observed for the stereoisomer 13- cis-RA (cRA). There was no apparent correlation of CFU-GM retinoid sensitivity with cloning efficiency or other colony characteristics. Interferon alpha-2a (INFα) alone strongly inhibited CFU-GM growth in all four CML-AP/BC cases ( ic 50 ⩽ 250 IU/ml) and three out of seven CML-CP cases ( ic 50 ⩽ 500 IU/ml), but there was little or no interactive effect between various concentrations of tRA and INFα (50 IU/ml) on CFU-GM from either CML-AP/BC or CML-CP cases. These results suggest that CML-AP/BC CFU-GM have some intrinsic molecular alteration(s) which markedly enhances their responsiveness to tRA and cRA, which may be clinically exploitable.