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1.  Minimal residual disease detection with tumor-specific CD160 correlates with event-free survival in chronic lymphocytic leukemia 
Blood Cancer Journal  2015;5(1):e273-.
In chronic lymphocytic leukemia (CLL), the detection of minimal residual disease (MRD) correlates with outcome in the trial setting. However, MRD assessment does not guide routine clinical management and its assessment remains complex. We incorporated detection of the B cell, tumor-specific antigen CD160 to develop a single-tube, flow cytometry assay (CD160FCA) for CLL MRD to a threshold of 10−4 to 10−5. One hundred and eighty-seven patients treated for CLL were enrolled. Utilizing the CD160FCA methodology, there was a high level of comparison between blood and bone marrow (R=0.87, P<0.001). In a validation cohort, CD160FCA and the international standardised approach of the European Research Initiative on CLL group demonstrated high concordance (R=0.91, P<0.01). Patients in complete remission (CR) and CD160FCA negative had longer event-free survival (EFS) (63 vs 16 months, P<0.01) and prolonged time to next treatment (60 vs 15 months, P<0.001) vs MRD positive patients; with a median time to MRD positivity of 36 months. In multivariate analysis, CD160FCA MRD detection was independently predictive of EFS in patients in CR and even predicted EFS in the good-risk cytogenetic subgroup. CD160FCA offers a simple assay for MRD detection in CLL and gives prognostic information across different CLL risk groups.
PMCID: PMC4314455  PMID: 25615279
2.  Novel recurrent mutations in ethanolamine kinase 1 (ETNK1) gene in systemic mastocytosis with eosinophilia and chronic myelomonocytic leukemia 
Blood Cancer Journal  2015;5(1):e275-.
Although KITD816V occurs universally in adult systemic mastocytosis (SM), the clinical heterogeneity of SM suggests presence of additional phenotype-patterning mutations. Because up to 25% of SM patients have KITD816V-positive eosinophilia, we undertook whole-exome sequencing in a patient with aggressive SM with eosinophilia to identify novel genetic alterations. We conducted sequencing of purified eosinophils (clone/tumor sample), with T-lymphocytes as the matched control/non-tumor sample. In addition to KITD816V, we identified a somatic missense mutation in ethanolamine kinase 1 (ETNK1N244S) that was not present in 50 healthy controls. Targeted resequencing of 290 patients showed ETNK1 mutations to be distributed as follows: (i) SM (n=82; 6% mutated); (ii) chronic myelomonocytic leukemia (CMML; n=29; 14% mutated); (iii) idiopathic hypereosinophilia (n=137; <1% mutated); (iv) primary myelofibrosis (n=32; 0% mutated); and (v) others (n=10; 0% mutated). Of the 82 SM cases, 25 had significant eosinophilia; of these 20% carried ETNK1 mutations. The ten mutations (N244S=6, N244T=1, N244K=1, G245A=2) targeted two contiguous amino acids in the ETNK1 kinase domain, and are predicted to be functionally disruptive. In summary, we identified novel somatic missense ETNK1 mutations that were most frequent in SM with eosinophilia and CMML; this suggests a potential pathogenetic role for dysregulated cytidine diphosphate-ethanolamine pathway metabolites in these diseases.
PMCID: PMC4314457  PMID: 25615281
3.  Autophagy collaborates with ubiquitination to downregulate oncoprotein E2A/Pbx1 in B-cell acute lymphoblastic leukemia 
Yuan, N | Song, L | Lin, W | Cao, Y | Xu, F | Liu, S | Zhang, A | Wang, Z | Li, X | Fang, Y | Zhang, H | Zhao, W | Hu, S | Wang, J | Zhang, S
Blood Cancer Journal  2015;5(1):e274-.
B-cell acute lymphoblastic leukemia (B-ALL) accounts for the most cancer incidences in children. We present here that autophagy is downregulated in pediatric B-ALL, suggesting a possible link between autophagy failure and pediatric B-ALL leukemogenesis. With a pediatric t(1;19) B-ALL xenograft mouse model, we show here that activation of autophagy by preventive administration of rapamycin improved the survival of leukemia animals by partial restoration of hematopoietic stem/progenitor cells, whereas treatment of the animals with rapamycin caused leukemia bone marrow cell-cycle arrest. Activation of autophagy in vitro or in vivo by rapamycin or starvation downregulated oncogenic fusion protein E2A/Pbx1. Furthermore, E2A/Pbx1 was found to be colocalized with autophagy marker LC3 in autolysosomes and with ubiquitin in response to autophagy stimuli, whereas autophagy or ubiquitination inhibitor blocked these colocalizations. Together, our data suggest a collaborative action between autophagy and ubiquitination in the degradation of E2A/Pbx1, thereby revealing a novel strategy for targeted preventive or treatment therapy on the pediatric ALL.
PMCID: PMC4314458  PMID: 25615280
4.  Reduced TET2 function leads to T-cell lymphoma with follicular helper T-cell-like features in mice 
Blood Cancer Journal  2014;4(12):e264-.
TET2 (Ten Eleven Translocation 2) is a dioxygenase that converts methylcytosine (mC) to hydroxymethylcytosine (hmC). TET2 loss-of-function mutations are highly frequent in subtypes of T-cell lymphoma that harbor follicular helper T (Tfh)-cell-like features, such as angioimmunoblastic T-cell lymphoma (30–83%) or peripheral T-cell lymphoma, not otherwise specified (10–49%), as well as myeloid malignancies. Here, we show that middle-aged Tet2 knockdown (Tet2gt/gt) mice exhibit Tfh-like cell overproduction in the spleen compared with control mice. The Tet2 knockdown mice eventually develop T-cell lymphoma with Tfh-like features after a long latency (median 67 weeks). Transcriptome analysis revealed that these lymphoma cells had Tfh-like gene expression patterns when compared with splenic CD4-positive cells of wild-type mice. The lymphoma cells showed lower hmC densities around the transcription start site (TSS) and higher mC densities at the regions of the TSS, gene body and CpG islands. These epigenetic changes, seen in Tet2 insufficiency-triggered lymphoma, possibly contributed to predated outgrowth of Tfh-like cells and subsequent lymphomagenesis. The mouse model described here suggests that TET2 mutations play a major role in the development of T-cell lymphoma with Tfh-like features in humans.
PMCID: PMC4315889  PMID: 25501021
5.  Decision analysis for donor selection in stem cell transplantation—HLA-8/8 allele-matched unrelated donor vs HLA-1 AG mismatched related donor 
Blood Cancer Journal  2014;4(12):e263-.
Risk of relapse during the unrelated donor coordination period biases comparisons between allogeneic hematopoietic stem cell transplantation from an HLA 8 of 8 allele-matched unrelated donor (8/8 MUD) and that from a related donor with an HLA-1 antigen mismatch in the graft-versus-host (GVH) direction (RD/1AGMM-GVH). To reduce this bias, we performed a decision analysis focusing on acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) in first complete remission (CR1). The primary outcome measure was 5-year survival probability with or without quality-of-life (QOL) adjustment. A baseline analysis showed that the decision to perform MUD transplantation was superior to that to perform RD/1AGMM-GVH transplantation for patients with AML or ALL. However, in the ALL cohort, the direction of superiority was reversed when the interval between CR1 and 8/8 MUD transplantation was >5.5 months (without QOL adjustment) or >6 months (after QOL adjustment) or when overall survival of RD/1AGMM-GVH transplantation improved by 1.3% without QOL adjustment and 2.1% after QOL adjustment. In conclusion, 8/8 MUD should be prioritized in transplantation for AML and ALL in CR1. However, the MUD coordination period and improvements in RD/1AGMM-GVH transplantation might change the donor selection priority in transplantation for ALL in CR1.
PMCID: PMC4315891  PMID: 25479570
6.  Concurrent IMRT and weekly cisplatin followed by GDP chemotherapy in newly diagnosed, stage IE to IIE, nasal, extranodal NK/T-Cell lymphoma 
Blood Cancer Journal  2014;4(12):e267-.
On the basis of the benefits of frontline radiation in early-stage, extranodal natural killer (NK)/T-cell lymphoma (ENKTL), we conducted the trial of concurrent chemoradiotherapy (CCRT) followed by three cycles of gemcitabine, dexamethasone and cisplatin (GDP). Thirty-two patients with newly diagnosed, stage IE to IIE, nasal ENKTL received CCRT (that is, all patients received intensity-modulated radiotherapy 56 Gy and cisplatin 30 mg/m2 weekly, 3–5 weeks). Three cycles of GDP (gemcitabine 1000 mg/m2 intravenously (i.v.) on days 1 and 8, dexamethasone 40 mg orally on days 1–4 and cisplatin 75 mg/m2 i.v. on day 1 (GDP), every 21 days as an outpatient were scheduled after CCRT. All patients completed CCRT, which resulted in 100% response that included 24 complete responses (CRs) and eight partial responses. The CR rate after CCRT was 75.0% (that is, 24 of 32 responses). Twenty-eight of the 32 patients completed the planned three cycles of GDP, whereas four patients did not because they withdrew (n=1) or because they had an infection (n=3). The overall response rate and the CR rate were 90.6% (that is, 29 of 32 responses) and 84.4% (that is, 27 of 32 responses), respectively. Only two patient experienced grade 3 toxicity during CCRT (nausea), whereas 13 of the 30 patients experienced grade 4 neutropenia. The estimated 3-year overall survival and progression-free rates were 87.50% and 84.38%, respectively. In conclusion, CCRT followed by GDP chemotherapy can be a feasible and effective treatment strategy for stage IE to IIE nasal ENKTL.
PMCID: PMC4315894  PMID: 25501024
7.  Modeling chronic myeloid leukemia in immunodeficient mice reveals expansion of aberrant mast cells and accumulation of pre-B cells 
Blood Cancer Journal  2014;4(12):e269-.
Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm that, if not treated, will progress into blast crisis (BC) of either myeloid or B lymphoid phenotype. The BCR-ABL1 fusion gene, encoding a constitutively active tyrosine kinase, is thought to be sufficient to cause chronic phase (CP) CML, whereas additional genetic lesions are needed for progression into CML BC. To generate a humanized CML model, we retrovirally expressed BCR-ABL1 in the cord blood CD34+ cells and transplanted these into NOD-SCID (non-obese diabetic/severe-combined immunodeficient) interleukin-2-receptor γ-deficient mice. In primary mice, BCR-ABL1 expression induced an inflammatory-like state in the bone marrow and spleen, and mast cells were the only myeloid lineage specifically expanded by BCR-ABL1. Upon secondary transplantation, the pronounced inflammatory phenotype was lost and mainly human mast cells and macrophages were found in the bone marrow. Moreover, a striking block at the pre-B-cell stage was observed in primary mice, resulting in an accumulation of pre-B cells. A similar block in B-cell differentiation could be confirmed in primary cells from CML patients. Hence, this humanized mouse model of CML reveals previously unexplored features of CP CML and should be useful for further studies to understand the disease pathogenesis of CML.
PMCID: PMC4315895  PMID: 25501026
8.  Inter- and intratumoral heterogeneity of BCL2 correlates with IgH expression and prognosis in follicular lymphoma 
Blood Cancer Journal  2014;4(10):e249-.
Most follicular lymphomas (FLs) are genetically defined by the t(14;18)(q32;q21) translocation that juxtaposes the BCL2 gene to the immunoglobulin heavy chain (IgH) 3' regulatory regions (IgH-3'RRs). Despite this recurrent translocation, FL cases are heterogeneous in terms of intratumoral clonal diversity for acquired mutations and variations in the tumor microenvironment. Here we describe an additional mechanism that contributes to inter- and intratumoral heterogeneity in FLs. By applying a novel single-molecule RNA fluorescence-based in situ hybridization (FISH) technique to detect mRNA molecules of BCL2 and IgH in single cells, we found marked heterogeneity in the number of BCL2 mRNA transcripts within individual lymphoma cells. Moreover, BCL2 mRNA molecules correlated with IgH mRNA molecules in individual cells both in t(14;18) lymphoma cell lines and in patient samples. Consistently, a strong correlation between BCL2 and IgH protein levels was found in a series of 205 primary FL cases by flow cytometry and immunohistochemistry. Inter- and intratumoral heterogeneity of BCL2 expression determined resistance to drugs commonly used in FL treatment and affected overall survival of FL patients. These data demonstrate that BCL2 and IgH expressions are heterogeneous and coregulated in t(14;18)-translocated cells, and determine the response to therapy in FL patients.
PMCID: PMC4220646  PMID: 25303368
9.  Comparative analysis of minimal residual disease detection by multiparameter flow cytometry and enhanced ASO RQ-PCR in multiple myeloma 
Blood Cancer Journal  2014;4(10):e250-.
Multiparameter flow cytometry (MFC) and allele-specific oligonucleotide real-time quantitative PCR (ASO RQ-PCR) are the two most sensitive methods to detect minimal residual disease (MRD) in multiple myeloma (MM). We compared these methods in 129 paired post-therapy samples from 22 unselected, consecutive MM patients in complete/near complete remission. Appropriate immunophenotypic and ASO RQ-PCR-MRD targets could be detected and MRD analyses constructed for all patients. The high PCR coverage could be achieved by gradual widening of the primer sets used for clonality detection. In addition, for 13 (55%) of the patients, reverse orientation of the ASO primer and individual design of the TaqMan probe improved the sensitivity and specificity of ASO RQ-PCR analysis. A significant nonlinear correlation prevailed between MFC-MRD and PCR-MRD when both were positive. Discordance between the methods was found in 32 (35%) paired samples, which were negative by MFC-MRD, but positive by ASO RQ-PCR. The findings suggest that with the described technique, ASO RQ-PCR can be constructed for all patients with MM. ASO RQ-PCR is slightly more sensitive in MRD detection than 6−10-color flow cytometry. Owing to technical demands ASO RQ-PCR could be reserved for patients in immunophenotypic remission, especially in efficacy comparisons between different drugs and treatment modalities.
PMCID: PMC4220647  PMID: 25303369
10.  Genetic polymorphisms and tissue expression of interleukin-22 associated with risk and therapeutic response of gastric mucosa-associated lymphoid tissue lymphoma 
Blood Cancer Journal  2014;4(10):eXX-.
Chronic Helicobacter pylori-stimulated immune reactions determine the pathogenesis of gastric mucosa-associated lymphoid tissue (MALT) lymphoma. We aimed to explore the genetic predisposition to this lymphoma and its clinical implication. A total of 68 patients and 140 unrelated controls were genotyped for 84 single-nucleotide polymorphisms in genes encoding cytokines, chemokines and related receptors that play important roles in T cell-mediated gastrointestinal immunity. Five genotypes in IL-22, namely CC at rs1179246, CC at rs2227485, AA at rs4913428, AA at rs1026788 and TT at rs7314777, were associated with disease susceptibility. The former four genotypes resided in the same linkage disequilibrium block (r2=0.99) that conferred an approximately threefold higher risk. In vitro experiments demonstrated that co-culturing peripheral mononuclear cells or CD4+ T cells with H. pylori stimulated the secretion of interleukin-22 (IL-22), and that IL-22 induced the expression of antimicrobial proteins, RegIIIα and lipocalin-2, in gastric epithelial cells. Furthermore, patients with gastric tissue expressing IL-22 were more likely to respond to H. pylori eradication (14/22 vs 4/19, P<0.006). We conclude that susceptibility of gastric MALT lymphoma is influenced by genetic polymorphisms in IL-22, the product of which is involved in mucosal immunity against H. pylori and associated with tumor response to H. pylori eradication.
PMCID: PMC4220648  PMID: 25303370
11.  Phase 1 dose-escalation study of IV ixazomib, an investigational proteasome inhibitor, in patients with relapsed/refractory lymphoma 
Blood Cancer Journal  2014;4(10):e251-.
Ixazomib is an investigational proteasome inhibitor that has shown preclinical activity in lymphoma models. This phase 1 study assessed the safety, tolerability, maximum tolerated dose (MTD), pharmacokinetics, pharmacodynamics and preliminary activity of intravenous (IV) ixazomib in relapsed/refractory lymphoma patients who had received ⩾2 prior therapies. Thirty patients with a range of histologies received ixazomib 0.125−3.11 mg/m2 on days 1, 8 and 15 of 28-day cycles. Patients received a median of two cycles (range 1−36). MTD was determined to be 2.34 mg/m2. Most common drug-related adverse events (AEs) included fatigue (43%), diarrhea (33%), nausea, vomiting and thrombocytopenia (each 27%). Drug-related grade ⩾3 AEs included neutropenia (20%), thrombocytopenia (13%) and diarrhea (10%). Drug-related peripheral neuropathy occurred in four (13%) patients; no grade ⩾3 events were reported. Plasma exposure increased dose proportionally from 0.5−3.11 mg/m2; terminal half-life was 4−12 days after multiple dosing. Of 26 evaluable patients, five achieved responses: 4/11 follicular lymphoma patients (one complete and three partial responses) and 1/4 peripheral T-cell lymphoma patients (partial response). Sustained responses were observed with ⩾32 cycles of treatment in two heavily pretreated follicular lymphoma patients. Results suggest weekly IV ixazomib is generally well tolerated and may be clinically active in relapsed/refractory lymphoma.
PMCID: PMC4220649  PMID: 25325301
12.  Markedly improved outcomes and acceptable toxicity in adolescents and young adults with acute lymphoblastic leukemia following treatment with a pediatric protocol: a phase II study by the Japan Adult Leukemia Study Group 
Blood Cancer Journal  2014;4(10):e252-.
The superiority of the pediatric protocol for adolescents with acute lymphoblastic leukemia (ALL) has already been demonstrated, however, its efficacy in young adults remains unclear. The ALL202-U protocol was conducted to examine the efficacy and feasibility of a pediatric protocol in adolescents and young adults (AYAs) with BCR–ABL-negative ALL. Patients aged 15–24 years (n=139) were treated with the same protocol used for pediatric B-ALL. The primary objective of this study was to assess the disease-free survival (DFS) rate and its secondary aims were to assess toxicity, the complete remission (CR) rate and the overall survival (OS) rate. The CR rate was 94%. The 5-year DFS and OS rates were 67% (95% confidence interval (CI) 58–75%) and 73% (95% CI 64–80%), respectively. Severe adverse events were observed at a frequency that was similar to or lower than that in children treated with the same protocol. Only insufficient maintenance therapy significantly worsened the DFS (hazard ratio 5.60, P<0.001). These results indicate that this protocol may be a feasible and highly effective treatment for AYA with BCR–ABL-negative ALL.
PMCID: PMC4220650  PMID: 25325302
13.  Plerixafor is superior to conventional chemotherapy for first-line stem cell mobilisation, and is effective even in heavily pretreated patients 
Blood Cancer Journal  2014;4(10):e255-.
This study (PHANTASTIC) compares first-line plerixafor with granulocyte colony-stimulating factor (G-CSF) in 98 myeloma and lymphoma patients with 151 historic controls mobilised by conventional chemotherapy+G-CSF. Eleven patients developed mild transient symptoms possibly related to plerixafor. No serious adverse events were seen. Seventy (71%) plerixafor-mobilised patients achieved both ⩾4 × 106 CD34+ cells/kg in ⩽2 aphereses and no neutropenia (<1.0 × 109/l). This is significantly >48 (32%) of 151 historical chemotherapy+G-CSF-mobilised control patients achieving this end point (P<0.001). Ninety-six (98%) plerixafor-mobilised patients achieved ⩾2 × 106 CD34+ cells/kg within one harvest round compared with 114 (75%) of controls (P=0.001). Engraftment times and 12-month outcome were comparable in both groups. Prior treatment was summarised by two scoring systems. Controls mobilising either >2.0 or >4.0 × 106 CD34+ cells/kg have significantly lower scores than mobilisation failures (P=0.002), but this relationship was not seen for plerixafor-mobilised patients. Plerixafor is a more effective and less toxic mobilising agent than conventional chemotherapy (especially in heavily pretreated patients), with comparable subsequent outcome, and merits consideration as the first-line standard of care for stem cell mobilisation.
PMCID: PMC4220652  PMID: 25360901
14.  Variable risk of second primary malignancy in multiple myeloma patients of different ethnic subgroups 
Blood Cancer Journal  2014;4(9):e243-.
Second primary malignancies (SPMs) among multiple myeloma (MM) patients have been reported with an estimated incidence varying from 1 to 15%. We have previously reported that significant disparity exists in MM survival across patients of different ethnicities. We undertook a Surveillance Epidemiology and End Results-based analysis to describe the incidence of SPMs among MM patients of different ethnicities, to explore the variable impact that SPMs might have on MM outcomes of patients across racial subgroups. We found that the risk of developing SPMs among MM patients is variable depending on the patient's ethnic background. This warrants further exploration of the impact of SPMs on outcomes of MM patients across different racial subgroups, especially in the form of prospective data collection and analyses.
PMCID: PMC4183772  PMID: 25192415
15.  A phase 2 study of MK-0457 in patients with BCR-ABL T315I mutant chronic myelogenous leukemia and philadelphia chromosome-positive acute lymphoblastic leukemia 
Blood Cancer Journal  2014;4(8):e238-.
Aurora kinase overexpression has been observed in patients with hematologic malignancies. MK-0457, a pan-aurora kinase inhibitor that also inhibits the ABL T315I mutant, was evaluated to treat patients with chronic myelogenous leukemia (CML) or Philadelphia chromosome (Ph+) acute lymphoblastic leukemia (ALL) with the T315I mutation. Adults with Ph+ chronic phase (CP)-, accelerated phase (AP)- or blast phase (BP)-CML, or ALL and documented BCR-ABL T315I mutation were treated with a 5-day continuous infusion of MK-0457 administered every 14 days at 40 mg/m2/h, 32 mg/m2/h or 24 mg/m2/h. Fifty-two patients (CP, n=15; AP, n=14; BP, n=11; Ph+ ALL, n=12) were treated. Overall, 8% of patients achieved major cytogenetic response; 6% achieved unconfirmed complete or partial response; 39% had no response. Two patients (CP CML) achieved complete hematologic response. No patients with advanced CML or Ph+ ALL achieved major hematologic response. The most common adverse event (AE) was neutropenia (50%). The most common grade 3/4 AEs were neutropenia (46%) and febrile neutropenia (35%). MK-0457 demonstrated minimal efficacy and only at higher, intolerable doses; lower doses were tolerated and no unexpected toxicities were observed. These data will assist in the development of future aurora kinase inhibitors and in the selection of appropriate target patient populations.
PMCID: PMC4219463  PMID: 25127392
16.  Percentage of urinary albumin excretion and serum-free light-chain reduction are important determinants of renal response in myeloma patients with moderate to severe renal impairment 
Blood Cancer Journal  2014;4(8):e235-.
Reversal of renal dysfunction significantly affects the prognosis of multiple myeloma (MM) with renal impairment (RI). There is no reliable test for predicting reversibility of RI in MM patients. We postulated that MM with high albuminuria may reflect glomerular disease that is difficult to reverse. Here, we examined the impact of urinary albumin excretion. We retrospectively analyzed 279 patients admitted to our hospital from April 2000 to December 2013. Clinical variables and laboratory data that may affect myeloma treatment response were extracted. The results were examined for relationship to renal response by univariate and multivariate analysis. RI (estimated glomerular filtration rate ≦50 ml/min per 1.73 m2) was observed in 116 patients (46%) and renal responses of renal complete response, renal partial response, renal minor response and no response were obtained in 46 (40%), 15 (13%), 13 (11%) and 42 (36%) patients, respectively. Although renal recovery was significantly associated with Durie–Salmon 1 or 2 (P=0.02), myeloma response better than very good partial response (P=0.03), involved free light-chain (iFLC) reduction from baseline 80% at day 12 (P=0.005), ≧95% at day 21 (P<0.001) and urinary albumin ≦25% on admission (P<0.001) on univariate analysis, only reduction of iFLC 95% at day 21 (P=0.015) and urinary albumin ≦25% (P=0.007) remained significant for any renal response. Our observation indicates that increased urinary albumin excretion >25% and reduction of iFLC ≦95% on day 21 were associated with favorable renal recovery in MM patients with RI, and were considered as negative predictors for renal response.
PMCID: PMC4219465  PMID: 25083819
17.  A pre-clinical model of resistance to induction therapy in pediatric acute lymphoblastic leukemia 
Blood Cancer Journal  2014;4(8):e232-.
Relapse and acquired drug resistance in T-cell acute lymphoblastic leukemia (T-ALL) remains a significant clinical problem. This study was designed to establish a preclinical model of resistance to induction therapy in childhood T-ALL to examine the emergence of drug resistance and identify novel therapies. Patient-derived T-ALL xenografts in immune-deficient (non-obese diabetic/severe combined immunodeficient) mice were exposed to a four-drug combination of vincristine, dexamethasone (DEX), L-asparaginase and daunorubicin (VXLD). ‘Relapse' xenografts were characterized by responses to drugs, changes in gene expression profiles and Connectivity Map (CMap) prediction of strategies to reverse drug resistance. Two of four xenografts developed ex vivo and in vivo drug resistance. Both resistant lines showed altered lipid and cholesterol metabolism, yet they had a distinct drug resistance pattern. CMap analyses reinforced these features, identifying the cholesterol pathway inhibitor simvastatin (SVT) as a potential therapy to overcome resistance. Combined ex vivo with DEX, SVT was significantly synergistic, yet when administered in vivo with VXLD it did not delay leukemia progression. Synergy of SVT with established chemotherapy may depend on higher drug doses than are tolerable in this model. Taken together, we have developed a clinically relevant in vivo model of T-ALL suitable to examine the emergence of drug resistance and to identify novel therapies.
PMCID: PMC4219466  PMID: 25083816
18.  Depletion of STAT5 blocks TEL–SYK-induced APMF-type leukemia with myelofibrosis and myelodysplasia in mice 
Blood Cancer Journal  2014;4(8):e240-.
The spleen tyrosine kinase (SYK) was identified as an oncogenic driver in a broad spectrum of hematologic malignancies. The in vivo comparison of three SYK containing oncogenes, SYKwt, TEL–SYK and IL-2-inducible T-cell kinase (ITK)-SYK revealed a general myeloexpansion and the establishment of three different hematologic (pre)diseases. SYKwt enhanced the myeloid and T-cell compartment, without leukemia/lymphoma development. ITK–SYK caused lethal T-cell lymphomas and the cytoplasmic TEL–SYK fusion induced an acute panmyelosis with myelofibrosis-type acute myeloid leukemia (AML) with up to 50% immature megakaryoblasts infiltrating bone marrow, spleen and liver, additional MPN features (myelofibrosis and granulocyte expansion) and MDS stigmata with megakaryocytic and erythroid dysplasia. LKS cells were reduced and all subsets (LT/ST/MPP) showed reduced proliferation rates. SYK inhibitor treatment (R788) of diseased TEL–SYK mice reduced leukocytosis, spleen and liver infiltration, enhanced the hematocrit and prolonged survival time, but could not significantly reduce myelofibrosis. Stat5 was identified as a major downstream mediator of TEL–SYK in vitro as well as in vivo. Consequently, targeted deletion of Stat5 in vivo completely abrogated TEL–SYK-induced AML and myelofibrosis development, proving Stat5 as a major driver of SYK-induced transformation. Our experiments highlight the important role of SYK in AML and myelofibrosis and prove SYK and STAT5 inhibitors as potent treatment options for those diseases.
PMCID: PMC4219468  PMID: 25148222
19.  Role of Bruton's tyrosine kinase (BTK) in growth and metastasis of INA6 myeloma cells 
Blood Cancer Journal  2014;4(8):e234-.
Bruton's tyrosine kinase (BTK) and the chemokine receptor CXCR4 are linked in various hematologic malignancies. The aim of the study was to understand the role of BTK in myeloma cell growth and metastasis using the stably BTK knockdown luciferase-expressing INA6 myeloma line. BTK knockdown had reduced adhesion to stroma and migration of myeloma cells toward stromal cell-derived factor-1. BTK knockdown had no effect on short-term in vitro growth of myeloma cells, although clonogenicity was inhibited and myeloma cell growth was promoted in coculture with osteoclasts. In severe combined immunodeficient-rab mice with contralaterally implanted pieces of bones, BTK knockdown in myeloma cells promoted their proliferation and growth in the primary bone but suppressed metastasis to the contralateral bone. BTK knockdown myeloma cells had altered the expression of genes associated with adhesion and proliferation and increased mammalian target of rapamycin signaling. In 176 paired clinical samples, BTK and CXCR4 expression was lower in myeloma cells purified from a focal lesion than from a random site. BTK expression in random-site samples was correlated with proportions of myeloma cells expressing cell surface CXCR4. Our findings highlight intratumoral heterogeneity of myeloma cells in the bone marrow microenvironment and suggest that BTK is involved in determining proliferative, quiescent or metastatic phenotypes of myeloma cells.
PMCID: PMC4219470  PMID: 25083818
20.  Clinical features and treatment outcome in newly diagnosed Chinese patients with multiple myeloma: results of a multicenter analysis 
Lu, J | Lu, J | Chen, W | Huo, Y | Huang, X | Hou, J
Blood Cancer Journal  2014;4(8):e239-.
The aim of this study was to understand the clinical features and treatment outcome of Chinese patients with multiple myeloma (MM). This retrospective study enrolled 940 newly diagnosed inpatients (median age, 59 years; immunoglobulin (Ig)D isotype, 6.5%) with complete follow-up data at three centers. In all, 85.8% of patients were of Durie-Salmon stage III and 48.3% were of International Staging System (ISS) stage III at diagnosis. Also, 9.6% of patients had extramedullary plasmacytoma. Compared with IgG, IgD-type patients were diagnosed at a younger age, and more patients were of ISS stage III, with hypercalcemia, elevated levels of lactate dehydrogenase, hyperuricemia, renal dysfunction and 1q21 amplification (P=0.03). The overall survival (OS) benefit was more prominent in IgG than in IgD when patients received bortezomib; however, they showed no significant difference when they received older therapies such as melphalan combined with prednisone or vincristine combined with adriamycin and dexamethasone. Fluorescence in situ hybridization (FISH) results showed that 17.6% had 17p13 deletion. Conventional cytogenetics revealed that 13.3% were hypodiploid and those cases had the worst survival, but hyperdiploid cases (9.3%) did not show any survival benefit compared with those with a normal karyotype (77.4%). Median OS and progression-free survival for all patients were 54 and 26 months, respectively. Significant factors for survival by multivariate analysis were gender, ISS stage, number of FISH abnormalities and extramedullary disease. MM in mainland China presents with different features, with patients being of younger age and having higher risk and more survival benefit in IgG patients receiving bortezomib.
PMCID: PMC4219472  PMID: 25127393
21.  Prognostic implications of CEBPA mutations in pediatric acute myeloid leukemia: a report from the Japanese Pediatric Leukemia/Lymphoma Study Group 
Blood Cancer Journal  2014;4(7):e226-.
CCAAT/enhancer-binding protein alpha (CEBPA) mutations are a favorable prognostic factor in adult acute myeloid leukemia (AML) patients; however, few studies have examined their significance in pediatric AML patients. Here we examined the CEBPA mutation status and clinical outcomes of pediatric AML patients treated in the AML-05 study. We found that 47 (14.9%) of the 315 evaluable patients harbored mutations in CEBPA; 26 cases (8.3%) harbored a single mutation (CEBPA-single) and 21 (6.7%) harbored double or triple mutations (CEBPA-double). After excluding core-binding factor-AML cases, patients harboring CEBPA mutations showed better overall survival (OS; P=0.048), but not event-free survival (EFS; P=0.051), than wild-type patients. Multivariate analysis identified CEBPA-single and CEBPA-double as independent favorable prognostic factors for EFS in the total cohort (hazard ratio (HR): 0.47 and 0.33; P=0.02 and 0.01, respectively). CEBPA-double was also an independent favorable prognostic factor for OS (HR: 0.30; P=0.04). CEBPA-double remained an independent favorable factor for EFS (HR: 0.28; P=0.04) in the normal karyotype cohort. These results suggest that CEBPA mutations, particularly CEBPA-double, are an independent favorable prognostic factor in pediatric AML patients, which will have important implications for risk-stratified therapy.
PMCID: PMC4219441  PMID: 25014773
22.  The glutathione synthesis inhibitor buthionine sulfoximine synergistically enhanced melphalan activity against preclinical models of multiple myeloma 
Blood Cancer Journal  2014;4(7):e229-.
Melphalan (L-PAM) has been an integral part of multiple myeloma (MM) treatment as a conditioning regimen before stem cell transplant (SCT). After initial response, most treated patients experience relapse with an aggressive phenotype. Increased glutathione (GSH) in MM may mediate resistance to L-PAM. We demonstrated that the GSH synthesis inhibitor buthionine sulfoximine (BSO) synergistically enhanced L-PAM activity (inducing 2–4 logs of cell kill) against nine MM cell lines (also in the presence of marrow stroma or cytokines) and in seven primary MM samples (combination indices <1.0). In MM cell lines, BSO significantly (P<0.05) depleted GSH, increased L-PAM-induced single-strand DNA breaks, mitochondrial depolarization, caspase cleavage and apoptosis. L-PAM depleted GSH, but GSH rapidly recovered in a L-PAM-resistant MM cell line unless also treated with BSO. Treatment with N-acetylcysteine antagonized BSO+L-PAM cytotoxicity without increasing GSH. In human MM xenografted into beige-nude-xid mice, BSO significantly depleted MM intracellular GSH and significantly increased apoptosis compared with L-PAM alone. BSO+L-PAM achieved complete responses (CRs) in three MM xenograft models including maintained CRs >100 days, and significantly increased the median event-free survival relative to L-PAM alone. Combining BSO with L-PAM warrants clinical testing in advanced MM.
PMCID: PMC4219442  PMID: 25036800
23.  Human HMGA2 protein overexpressed in mice induces precursor T-cell lymphoblastic leukemia 
Blood Cancer Journal  2014;4(7):e227-.
T-cell acute lymphoblastic leukemia (T-ALL) is a neoplasia of thymocytes characterized by the rapid accumulation of the precursors of T lymphocytes. HMGA2 (high-mobility group AT-hook 2) gene expression is extremely low in normal adult tissues, but it is overexpressed in many tumors. To identify the biological function of HMGA2, we generated transgenic mice carrying the human HMGA2 gene under control of the VH promoter/Eμ enhancer. Approximately 90% of Eμ-HMGA2 transgenic mice became visibly sick between 4 and 8 months due to the onset and progression of a T-ALL-like disease. Characteristic features included severe alopecia (30% of mice); enlarged lymph nodes and spleen; and profound immunological abnormalities (altered cytokine levels, hypoimmunoglobulinemia) leading to reduced immune responsiveness. Immunophenotyping showed accumulation of CD5+CD4+, CD5+CD8+ or CD5+CD8+CD4+ T-cell populations in the spleens and bone marrow of sick animals. These findings show that HMGA2-driven leukemia in mice closely resembles spontaneous human T-ALL, indicating that HMGA2 transgenic mice should serve as an important model for investigating basic mechanisms and potential new therapies of relevance to human T-ALL.
PMCID: PMC4219444  PMID: 25014774
24.  Notch pathway inhibition controls myeloma bone disease in the murine MOPC315.BM model 
Blood Cancer Journal  2014;4(6):e217-.
Despite evidence that deregulated Notch signalling is a master regulator of multiple myeloma (MM) pathogenesis, its contribution to myeloma bone disease remains to be resolved. Notch promotes survival of human MM cells and triggers human osteoclast activity in vitro. Here, we show that inhibition of Notch through the γ-secretase inhibitor XII (GSI XII) induces apoptosis of murine MOPC315.BM myeloma cells with high Notch activity. GSI XII impairs murine osteoclast differentiation of receptor activator of NF-κB ligand (RANKL)-stimulated RAW264.7 cells in vitro. In the murine MOPC315.BM myeloma model GSI XII has potent anti-MM activity and reduces osteolytic lesions as evidenced by diminished myeloma-specific monoclonal immunoglobulin (Ig)-A serum levels and quantitative assessment of bone structure changes via high-resolution microcomputed tomography scans. Thus, we suggest that Notch inhibition through GSI XII controls myeloma bone disease mainly by targeting Notch in MM cells and possibly in osteoclasts in their microenvironment. We conclude that Notch inhibition is a valid therapeutic strategy in MM.
PMCID: PMC4080208  PMID: 24927406
25.  The novel immunotoxin HM1.24-ETA′ induces apoptosis in multiple myeloma cells 
Blood Cancer Journal  2014;4(6):e219-.
Despite new treatment modalities, the clinical outcome in a substantial number of patients with multiple myeloma (MM) has yet to be improved. Antibody-based targeted therapies for myeloma patients could make use of the HM1.24 antigen (CD317), a surface molecule overexpressed on malignant plasma cells and efficiently internalized. Here, a novel immunotoxin, HM1.24-ETA′, is described. HM1.24-ETA′ was generated by genetic fusion of a CD317-specific single-chain Fv (scFv) antibody and a truncated variant of Pseudomonas aeruginosa exotoxin A (ETA′). HM1.24-ETA′ inhibited growth of interleukin 6 (IL-6)-dependent and -independent myeloma cell lines. Half-maximal growth inhibition was observed at concentrations as low as 0.3 nM. Target cell killing occurred via induction of apoptosis and was unaffected in co-culture experiments with bone marrow stromal cells. HM1.24-ETA′ efficiently triggered apoptosis of freshly isolated/cryopreserved cells of patients with plasma cell leukemia and MM and was active in a preclinical severe combined immunodeficiency (SCID) mouse xenograft model. Importantly, HM1.24-ETA′ was not cytotoxic against CD317-positive cells from healthy tissue (monocytes, human umbilical vein endothelial cells). These results indicate that CD317 may represent a promising target structure for specific and efficient immunotoxin therapy for patients with plasma cell tumors.
PMCID: PMC4080209  PMID: 24927408

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