MicroRNAs (miRs) are deregulated in cancer and leukemia. Restoring aberrantly downregulated tumor suppressor miRs or antagonizing overexpressed oncogenic miRs in malignant cells by synthetic RNA oligonucleotides represents a potentially novel therapeutic approach in cancer and leukemia. However, given the complex networking and concurrent deregulation of miRs in malignant cells, an effective approach may require concurrent targeting of multiple miRs. Cassette dosing involves simultaneous administration of a mixture of oligonucleotides from same or different structural classes. However, information on cassette dosing pharmacokinetics, tissue distribution and bioactivity of synthetic miRs is lacking. In this study, three synthetic 2’-methoxyphosphorothioate-miRs (2’-MeOPSmiR16-1, 2’-MeOPSmiR29b and 2’-MeOPSantagomiR155) were administered i.v. to C57BL/6 mice as a mixture, each at 7.5mg/kg. Analysis of concentrations of individual miR in plasma and major organ tissues (bone marrow, spleen, liver, brain, heart, kidney and lung) was performed. The mRNA and protein levels of miR’s bio-targets were monitored sequentially after dosing up to 24 hours. Our results demonstrated that these synthetic miRs retain their different individual pharmacokinetic properties and all display three-compartmental pharmacokinetics. 2’-MeOPSmiR16-1 has the longest plasma gamma half-life of 2508 minutes and lowest total body clearance of 0.0054 L/min*kg, whereas 2’-MeOPSmiR29b has the shortest gamma half-life of 510.6 minutes and highest total body clearance of 0.042 L/min*kg. The tissue concentrations of all three 2’-MeOPS-modified miR(s)/antagomiR were measurable from 5 minutes to at least 24 hours after dosing, indicating that these concurrently delivered oligonucleotides can reach organ tissues. Importantly, there were biological activities of the concurrently administered miRs which persisted, as shown by the downregulation of specific targets in tested tissues, albeit with variations. Brain was one of the most sensitive tissues with respect to downregulation of mRNA and protein levels of four measured bio-targets (e.g. Bcl-2, Mcl-1, DNMT3a and DNMT3b) despite its relatively low miR/antagomiRs levels. We conclude that cassette dosing is applicable to 2’-MeOPS-modified synthetic miRs that are tissue-deliverable and biofunctional without any additional formulation requirement. This study supports future exploration of miR-involved combination therapies.
2’-MeOPSmiRs; cassette dosing; pharmacokinetics; tissue distribution; pharmacodynamic
To identify a robust prognostic gene expression signature as an independent predictor of survival of patients with acute myeloid leukemia (AML) and use it to improve established risk classification.
Patients and Methods
Four independent sets totaling 499 patients with AML carrying various cytogenetic and molecular abnormalities were used as training sets. Two independent patient sets composed of 825 patients were used as validation sets. Notably, patients from different sets were treated with different protocols, and their gene expression profiles were derived using different microarray platforms. Cox regression and Kaplan-Meier methods were used for survival analyses.
A prognostic signature composed of 24 genes was derived from a meta-analysis of Cox regression values of each gene across the four training sets. In multivariable models, a higher sum value of the 24-gene signature was an independent predictor of shorter overall (OS) and event-free survival (EFS) in both training and validation sets (P < .01). Moreover, this signature could substantially improve the European LeukemiaNet (ELN) risk classification of AML, and patients in three new risk groups classified by the integrated risk classification showed significantly (P < .001) distinct OS and EFS.
Despite different treatment protocols applied to patients and use of different microarray platforms for expression profiling, a common prognostic gene signature was identified as an independent predictor of survival of patients with AML. The integrated risk classification incorporating this gene signature provides a better framework for risk stratification and outcome prediction than the ELN classification.
We sought to reduce the risk of infectious complications and non-relapse mortality (NRM) associated with the use of antithymocyte globulin (ATG) without compromising control of acute graft-versus-host disease (GVHD) in patients undergoing reduced intensity conditioning (RIC) transplantation.
As part of an ongoing quality improvement effort, we lowered the dose of rabbit ATG from 7.5 mg/kg of ATG (R-ATG) (n=39) to 6.0 mg/kg of ATG (r-ATG) (n=33) in association with fludarabine and busulfan RIC transplantation and then monitored patients for adverse events, relapse, and survival.
Of the 72 mostly high risk (82%) patients studied, 89% received unrelated donor allografts, 25% of which were HLA-mismatched. No differences in post-transplantation full donor-cell chimerism rates were observed between the two ATG-dose groups (p>0.05). When R-ATG vs. r-ATG patients were compared, we observed no significant difference in the cumulative incidence of grade II–IV acute GVHD (32% vs. 27%; p-=0.73) or grade III–IV acute GVHD (23% vs. 11%; p=0.28). However, the r-ATG group had significantly less CMV reactivation (64% vs. 30%; p=0.005) and bacterial infections (56% vs. 18%; p=0.001), a better 1-year cumulative incidence of NRM (18% vs. 3%; p=0.03) and a trend for better 1-year overall survival (64% vs. 84%; p=0.07) compared to R-ATG patients.
A seemingly modest reduction in the dose of rabbit ATG did not compromise control of acute GVHD or achievement of donor chimerism but led to a significant decrease in the risk of serious infections and NRM in high risk RIC allograft recipients.
Fludarabine; busulfan; thymoglobulin; antithymocyte globulin; allogeneic stem cell transplantation; graft-versus-host disease
Aberrant expression of the secreted protein, acidic, cysteine-rich (osteonectin) (SPARC) gene, which encodes a matricellular protein that participates in normal tissue remodeling, is associated with a variety of diseases including cancer, but the contribution of SPARC to malignant growth remains controversial. We previously reported that SPARC was among the most upregulated genes in cytogenetically normal acute myeloid leukemia (CN-AML) patients with gene-expression profiles predictive of unfavorable outcome, such as mutations in isocitrate dehydrogenase 2 (IDH2-R172) and overexpression of the oncogenes brain and acute leukemia, cytoplasmic (BAALC) and v-ets erythroblastosis virus E26 oncogene homolog (ERG). In contrast, SPARC was downregulated in CN-AML patients harboring mutations in nucleophosmin (NPM1) that are associated with favorable prognosis. Based on these observations, we hypothesized that SPARC expression is clinically relevant in AML. Here, we found that SPARC overexpression is associated with adverse outcome in CN-AML patients and promotes aggressive leukemia growth in murine models of AML. In leukemia cells, SPARC expression was mediated by the SP1/NF-κB transactivation complex. Furthermore, secreted SPARC activated the integrin-linked kinase/AKT (ILK/AKT) pathway, likely via integrin interaction, and subsequent β-catenin signaling, which is involved in leukemia cell self-renewal. Pharmacologic inhibition of the SP1/NF-κB complex resulted in SPARC downregulation and leukemia growth inhibition. Together, our data indicate that evaluation of SPARC expression has prognosticative value and SPARC is a potential therapeutic target for AML.
Promoter hypermethylation associated tumor suppressor genes (TSGs) silencing has been explored as a therapeutic target for hypomethylating agents. Promoter methylation change may serve as a pharmacodynamic endpoint for evaluation of the efficacy of these agents and predict the patient’s clinical response. Herein, a LC-MS/MS assay has been developed for quantitative regional DNA methylation analysis using the molar ratio of 5-methyl-2′-deoxycytidine (5mdC) to 2′-deoxycytidine (2dC) in the enzymatic hydrolysate of fully methylated bisulfite-converted PCR amplicons as the methylation indicator. The assay can differentiate 5% of promoter methylation level with an intra-day precision ranging from 3.00 to 16.0% using two TSGs: HIN-1 and RASSF1A. This method was applied to characterize decitabine-induced promoter DNA methylation changes of these two TSGs in a breast cancer MCF-7 cell line. Promoter methylation of these TSGs was found to decrease in a dose-dependent manner. Correspondingly, the expression of these TSGs was enhanced. The sensitivity and reproducibility of the method make it a valuable tool for specific gene methylation analysis, which could aid characterization of hypomethylating activity on specific genes by hypomethylating agents in a clinical setting.
Regional DNA Methylation; LC-MS/MS; Quantification
The purpose of this study was to determine remission induction frequency when bortezomib was combined with daunorubicin and cytarabine in previously untreated older adults with acute myeloid leukemia (AML) and safety of bortezomib in combination with consolidation chemotherapy consisting of intermediate-dose cytarabine (Int-DAC).
Patients and Methods
Ninety-five adults (age 60 to 75 years; median, 67 years) with previously untreated AML (including therapy-related and previous myelodysplastic syndrome) received bortezomib 1.3 mg/m2 intravenously (IV) on days 1, 4, 8, and 11 with daunorubicin 60 mg/m2 on days 1 through 3 and cytarabine 100 mg/m2 by continuous IV infusion on days 1 through 7. Patients who achieved complete remission (CR) received up to two courses of consolidation chemotherapy with cytarabine 2 gm/m2 on days 1 through 5 with bortezomib. Three cohorts with escalating dose levels of bortezomib were tested (0.7, 1.0, and 1.3 mg/m2). Dose-limiting toxicities were assessed during the first cycle of consolidation. The relationship between cell surface expression of CD74 and clinical outcome was assessed.
Frequency of CR was 65% (62 of 95), and 4% of patients (four of 95) achieved CR with incomplete platelet recovery (CRp). Eleven patients developed grade 3 sensory neuropathy. Bortezomib plus Int-DAC proved tolerable at the highest dose tested. Lower CD74 expression was associated with CR/CRp (P = .04) but not with disease-free or overall survival.
The addition of bortezomib to standard 3 + 7 daunorubicin and cytarabine induction chemotherapy for AML resulted in an encouraging remission rate. The maximum tested dose of bortezomib administered in combination with Int-DAC for remission consolidation was 1.3 mg/m2 and proved tolerable. Further testing of this regimen is planned.
MicroRNAs (miRNAs) are evolutionary conserved small non-coding RNAs that regulate gene expression. Early studies have shown that miRNA expression is deregulated in cancer, and experimental data indicate that cancer phenotypes can be modified by targeting miRNA expression. Based on these observations, miRNA-based anticancer therapies are being developed either alone or in combination with current targeted therapies, with the goal to improve disease response and increase cure rate. The advantage of using miRNA approaches is based on the ability to concurrently target multiple effectors of pathways involved in cell differentiation, proliferation and survival. In this review, we describe the role of miRNAs in tumorigenesis, and critically discuss the rationale, strategies and challenges for therapeutic targeting of miRNAs in cancer.
Corticosteroids are widely used for the treatment of B-cell malignancies, including non-Hodgkin lymphoma, chronic lymphocytic leukemia (CLL), and acute lymphoblastic leukemia; however, this class of drug is associated with undesirable off-target effects. Herein, we developed novel milatuzumab-conjugated liposomes as a targeted dexamethasone carrier for therapeutic delivery in CD74+ B-cell malignancies and explored its effect against the disease.
The targeting efficiency of milatuzumab-targeted liposomes to CD74+ cells was evaluated in vitro. The effect of CD74-targeted liposomal dexamethasone was compared with free dexa-methasone in primary CLL cells and cell lines in vitro. The therapeutic efficacy of CD74-targeted liposomal dexamethasone was evaluated in a Raji-severe combined immunodeficient (SCID) xenograft model in vivo.
Milatuzumab-targeted liposomes promoted selective incorporation of carrier molecules into transformed CD74-positive B cells as compared with CD74-negative T-cells. The CD74-dexamethasone-targeted liposomes (CD74-IL-DEX) promoted and increased killing in CD74-positive tumor cells and primary CLL cells. Furthermore, the targeted drug liposomes showed enhanced therapeutic efficacy against a CD74-positive B-cell model as compared with free, or non-targeted, liposomal dexamethasone in SCID mice engrafted with Raji cells in vivo.
These studies provide evidence and support for a potential use of CD74-targeted liposomal dexamethasone as a new therapy for B-cell malignancies.
Acquired chromosome abnormalities in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) are among the most valuable determinants of diagnosis and prognosis. In search of new recurrent balanced translocations we reviewed the Cancer and Leukemia Group B (CALGB) cytogenetics database containing pretreatment and relapse karyotypes of 4,701 adults with AML and 565 with MDS who were treated on CALGB trials. We identified all cases with balanced structural rearrangements occurring as a sole abnormality or in addition to one other abnormality, excluded abnormalities known to be recurrent, and then reviewed the literature to determine whether any of what we considered unique, previously unknown abnormalities had been reported. As a result, we identified seven new recurrent balanced translocations in AML or MDS: t(7;11)(q22;p15.5), t(10;11)(q23;p15), t(2;12)(p13;p13), t(12;17)(p13;q12), t(2;3)(p21;p21), t(5;21)(q31;q22) and t(8;14)(q24.1;q32.2), and, additionally, t(10;12)(p11;q15), a new translocation in AML previously reported in a case of acute lymphoblastic leukemia. Herein we report hematologic and clinical characteristics, and treatment outcomes of patients with these newly recognized recurrent translocations. We also report 52 unique balanced translocations, together with the clinical data of patients harboring them, that to our knowledge have not been previously published. We hope that once the awareness of their existence is increased, some of these translocations may become recognized as novel recurring abnormalities. Identification of additional cases with both the new recurrent and the unique balanced translocations will enable determination of their prognostic significance and help to provide insights into the mechanisms of disease pathogenesis in patients with these rare abnormalities.
To evaluate the prognostic significance of the international European LeukemiaNet (ELN) guidelines for reporting genetic alterations in acute myeloid leukemia (AML).
Patients and Methods
We analyzed 1,550 adults with primary AML, treated on Cancer and Leukemia Group B first-line trials, who had pretreatment cytogenetics and, for cytogenetically normal patients, mutational status of NPM1, CEBPA, and FLT3 available. We compared complete remission (CR) rates, disease-free survival (DFS), and overall survival (OS) among patients classified into the four ELN genetic groups (favorable, intermediate-I, intermediate-II, adverse) separately for 818 younger (age < 60 years) and 732 older (age ≥ 60 years) patients.
The percentages of younger versus older patients in the favorable (41% v 20%; P < .001), intermediate-II (19% v 30%; P < .001), and adverse (22% v 31%; P < .001) genetic groups differed. The favorable group had the best and the adverse group the worst CR rates, DFS, and OS in both age groups. Both intermediate groups had significantly worse outcomes than the favorable but better than the adverse group. Intermediate-I and intermediate-II groups in older patients had similar outcomes, whereas the intermediate-II group in younger patients had better OS but not better CR rates or DFS than the intermediate-I group. The prognostic significance of ELN classification was confirmed by multivariable analyses. For each ELN group, older patients had worse outcomes than younger patients.
The ELN classification clearly separates the genetic groups by outcome, supporting its use for risk stratification in clinical trials. Because they have different proportions of genetic alterations and outcomes, younger and older patients should be reported separately when using the ELN classification.
Acute myelogenous leukemia (AML) subtypes that result from oncogenic activation of homeobox (HOX) transcription factors are associated with poor prognosis. The HOXA9 transcription activator and growth factor independent 1 (GFI1) transcriptional repressor compete for occupancy at DNA-binding sites for the regulation of common target genes. We exploited this HOXA9 versus GFI1 antagonism to identify the genes encoding microRNA-21 and microRNA-196b as transcriptional targets of HOX-based leukemia oncoproteins. Therapeutic inhibition of microRNA-21 and microRNA-196b inhibited in vitro leukemic colony forming activity and depleted in vivo leukemia-initiating cell activity of HOX-based leukemias, which led to leukemia-free survival in a murine AML model and delayed disease onset in xenograft models. These data establish microRNA as functional effectors of endogenous HOXA9 and HOX-based leukemia oncoproteins, provide a concise in vivo platform to test RNA therapeutics, and suggest therapeutic value for microRNA antagonists in AML.
This phase I study was conducted to determine the maximum tolerated dose (MTD) and dose limiting toxicities (DLT) of the heat shock protein 90 (HSP90) inhibitor 17-allyamino-17-demethoxygeldanamycin (17-AAG) in combination with bortezomib, and to provide pharmacokinetic data in relapsed or refractory acute myeloid leukemia (AML). Eleven patients were enrolled. The MTD was 17-AAG 150mg/m2 and bortezomib 0.7mg/m2. Hepatic toxicity and cardiac toxicity were dose limiting. Co-administration on day 4 led to a decrease in clearance (p=0.005) and increase in AUC (p=.032) of 17-amino-17-demethoxygeldanamycin (17-AG) not observed when 17-AAG was administered alone. Pharmacokinetic parameters of patients who developed toxicities and those who did not were not different. The combination of 17-AAG and bortezomib led to toxicity without measurable response in patients with relapsed or refractory AML. Pharmacokinetic data provide insight for studies of related agents in AML; next generation HSP90 inhibitors are appealing for further development in this area.
Relapsed AML; bortezomib; 17-AAG; heat shock protein inhibition
Decitabine (DAC) is used for treatment of patients with myelodysplastic syndromes and acute myeloid leukemia (AML). Following cellular uptake, DAC is activated to DAC-triphosphate (TP) and incorporated into DNA. Once incorporated into the DNA, DAC-TP binds and inactivates DNA methyltransferases (DNMTs), thereby leading to hypomethylation and re-expression of epigenetically silenced tumor suppressor genes and ultimately antileukemia activity. However, direct evidence of in vivo DAC-TP occurrence in DAC-treated patients has been difficult to demonstrate due to a lack of suitable validated analytical methodology. Thus, we developed and validated a nonradioactive sensitive and specific LC-MS/MS assay for quantification of DAC-TP. The assay is linear from 50 to 1,000 nM and from 1 to 10 μM and has a lower limit of quantitation of 50 nM and a coefficient of variation for both within- and between-day precision <20%. Following DAC treatment, we detected DAC-TP in parental and DAC-resistant AML cells (in vitro) and bone marrow (BM) and spleen of normal and leukemic mice (in vivo). Downregulation of DNMTs and correlation of DAC-TP concentration with proteins involved in mechanisms of DAC resistance were also demonstrated. The clinical applicability of this method was proven by measuring DAC-TP level in BM and blood mononuclear cells from DAC-treated AML patients. Higher levels are seemingly associated with clinical response. Monitoring the DAC-TP intracellular level may serve as a novel pharmacological endpoint for designing more effective DAC-based regimens.
acute myeloid leukemia; decitabine; metabolite; quantification method; triphosphate
The regulatory protein nucleolin controls the expression of a subset of miRNAs involved in breast cancer progression and can be targeted to inhibit breast cancer growth in vivo.
Numerous studies have described the altered expression and the causal role of microRNAs (miRNAs) in human cancer. However, to date, efforts to modulate miRNA levels for therapeutic purposes have been challenging to implement. Here we find that nucleolin (NCL), a major nucleolar protein, posttranscriptionally regulates the expression of a specific subset of miRNAs, including miR-21, miR-221, miR-222, and miR-103, that are causally involved in breast cancer initiation, progression, and drug resistance. We also show that NCL is commonly overexpressed in human breast tumors and that its expression correlates with that of NCL-dependent miRNAs. Finally, inhibition of NCL using guanosine-rich aptamers reduces the levels of NCL-dependent miRNAs and their target genes, thus reducing breast cancer cell aggressiveness both in vitro and in vivo. These findings illuminate a path to novel therapeutic approaches based on NCL-targeting aptamers for the modulation of miRNA expression in the treatment of breast cancer.
We compared the outcomes of acute myeloid leukemia (AML) patients aged 60–70 years receiving reduced-intensity allogeneic hematopoietic cell transplantation (HCT) in first remission (CR1) reported to the Center for International Blood and Marrow Research (CIBMTR) (N=94) with outcomes in patients treated with induction and post-remission chemotherapy on Cancer and Leukemia Group B (CALGB) protocols (N=96). All patients included had remained in CR1 for at least 4 months. HCT recipients were slightly younger than chemotherapy patients (median ages: 63 v 65 years; P<0.001), with no significant differences in the proportion with therapy-related leukemia or in different cytogenetic risk groups. Time from diagnosis to CR1 was longer for HCT recipients (median: 44 v 38 days; P=0.031). Allogeneic HCT was associated with significantly lower risk of relapse (32% v 81% at 3 years; P<0.001), higher non-relapse mortality (36% v 4% at 3 years; P<0.001), and longer leukemia-free survival (32% v 15% at 3 years; P=0.001). Although overall survival was longer for HCT recipients, this was not statistically significant (37% v 25% at 3 years; P=0.08). RIC allogeneic HCT in CR1 AML patients aged 60–70 years reduces relapse and improves leukemia-free survival. Strategies that reduce non-relapse mortality may yield significant improvements in overall survival.
acute myeloid leukemia; allogeneic; reduced-intensity transplantation
Transferrin (Tf) conjugated lipopolyplexes (LPs) carrying G3139, an antisense oligonucleotide for Bcl-2, were synthesized and evaluated in Tf receptor positive K562 erythroleukemia cells and then in a murine K562 xenograft model.
Materials and Methods
Particle size and Zeta potentials of transferrin conjugated lipopolyplexs containing G3139 (Tf-LP-G3139) were measured by Dynamic Light Scattering and ZetaPALS. In vitro and in vivo sample’s Bcl-2 downregulation was analyzed using Western blot and tumor tissue samples also exhibited by immunohistochemistry method. For athymic mice bearing with K562 xenograft tumors, tumor growth inhibition and survival rate were investigated. Nanoparticle distribution in 3-D cell cluster was observed by Laser scan confocal microscopy. IL-12 production in the plasma was measured by ELISA kit.
In vitro, Tf-LP-G3139 was more effective in inducing down regulation of Bcl-2 in K562 cells than non-targeted LP-G3139, free G3139 and mismatched control ODN-G4126 in the same formulation. In vivo Tf-LP-G3139 was less effective than free G3139 in Bcl-2 down regulation. 3-D cell cluster model diffusion results indeed indicated limited penetration of the LPs into the cell cluster. Finally, the therapeutic efficacies of Tf-LP-G3139 and free G3139 were determined in the K562 xenograft model. Tf-LP-G3139 showed slower plasma clearance, higher AUC, and greater accumulation in the tumor compared to free G3139. In addition, Tf-LP-G3139 was found to be more effective in tumor growth inhibition and prolonging mouse survival than free G3139. This was associated with increased spleen weight and IL-12 production in the plasma.
The role of the immune system in the therapeutic response obtained with the Tf-LPs is necessary and in vitro 3-D cell cluster model can be a potential tool to evaluate the nanoparticle distribution.
Bcl-2; leukemia; lipopolyplexs; targeted drug delivery; transferrin receptor
Disulfide-linked oligodeoxyribonucleotide (ODN) liposomes were formulated and evaluated for the delivery of antisense ODN G3139 in KB human oral carcinoma cells.
Materials and Methods
Liposomes composed of 1,2-di-(9Z-octadecenoyl)-3-trimethylammo-nium-propane (DOTAP)/egg phosphatidylcholine/α-tocopheryl polyethylene glycol 1000 succinate were incorporated with hydrophobized disulfide-linked ODN. Disulfide-linked ODN liposomes were characterized for their size, ODN intracellular delivery, Bcl-2 mRNA and protein expression, growth inhibition, and chemosensitization.
Intracellular delivery of ODN with disulfide-linked ODN liposomes was more efficient than that with non-liposomal hydrophobized disulfide-linked ODN. Treatment of the cells with disulfide-linked ODN liposomes resulted in efficient Bcl-2 down-regulation greater than that with hydrophobized disulfide-linked ODN and consistent with that of cellular growth inhibition and the sensitization to daunorubicin in KB cells. Disulfide-linked ODN liposomes exhibited superior colloidal stability during 5-week storage.
Disulfide-linked liposomes are effective delivery vehicles for antisense ODN.
Liposomes; disulfide; antisense oligonucleotide; G3139; Bcl-2; drug delivery
Histone deacetylase (HDAC) inhibitors either alone or in combination with hypomethylating agents have limited clinical effect in acute myeloid leukemia (AML). Previously we demonstrated that AML patients with higher miR-29b expression had better response to the hypomethylating agent decitabine. Therefore, an increase in miR-29b expression preceding decitabine treatment may provide a therapeutic advantage. We previously showed that miR-29b expression is suppressed by a repressor complex that includes HDACs. Thus, HDAC inhibition may increase miR-29b expression. We hypothesized that priming AML cells with the novel HDAC inhibitor (HDACI) AR-42 would result in increased response to decitabine treatment via upregulation of miR-29b. Here we show that AR-42 is a potent HDACI in AML, increasing miR-29b levels and leading to downregulation of known miR-29b targets (i.e., SP1, DNMT1, DNMT3A, and DNMT3B). We then demonstrated that the sequential administration of AR-42 followed by decitabine resulted in a stronger anti-leukemic activity in vitro and in vivo than decitabine followed by AR-42 or either drug alone. These preclinical results with AR-42 priming before decitabine administration represents a promising, novel treatment approach and a paradigm shift with regard to the combination of epigenetic-targeting compounds in AML, where decitabine has been traditionally given before HDAC inhibitors.
acute myeloid leukemia; HDACI; AR-42; decitabine; miR-29b
The impact of mutation of the ATM (ataxia telangiectasia mutated) gene in chronic lymphocytic leukemia (CLL) treatment outcome has not been examined. We studied ATM mutations in 73 patients treated with fludarabine and rituximab. ATM gene mutation analysis was performed using temperature gradient capillary electrophoresis. The impact of detected variants on overall survival (OS) and progression-free survival (PFS) was tested with proportional hazards models. None of the 73 patients demonstrated truncating ATM mutations; 17 (23%, 95% confidence interval 14 – 35%) had non-silent variants (ATM-NSVs), including 13 known ATM polymorphisms and four missense variants. ATM-NSVs were not significantly associated with any baseline characteristics including immunoglobulin heavy chain variable gene (IGVH) status. In multivariable models, no significant differences in complete response (p = 0.70), PFS (p = 0.59) or OS (p = 0.13) were observed. Our data indicate that truncating ATM mutations are rare in patients with CLL. Furthermore, in this dataset, these non-silent variants had limited impact on PFS and OS.
Chronic lymphocytic leukemia; ATM mutation; prognosis; chemoimmunotherapy
To determine the association of RUNX1 mutations with therapeutic outcome in younger and older patients with primary cytogenetically normal acute myeloid leukemia (CN-AML) and with gene/microRNA expression signatures.
Patients and Methods
Younger (< 60 years; n = 175) and older (≥ 60 years; n = 225) patients with CN-AML treated with intensive cytarabine/anthracycline-based first-line therapy on Cancer and Leukemia Group B protocols were centrally analyzed for RUNX1 mutations by polymerase chain reaction and direct sequencing and for established prognostic gene mutations. Gene/microRNA expression profiles were derived using microarrays.
RUNX1 mutations were found in 8% and 16% of younger and older patients, respectively (P = .02). They were associated with ASXL1 mutations (P < .001) and inversely associated with NPM1 (P < .001) and CEBPA (P = .06) mutations. RUNX1-mutated patients had lower complete remission rates (P = .005 in younger; P = .006 in older) and shorter disease-free survival (P = .058 in younger; P < .001 in older), overall survival (P = .003 in younger; P < .001 in older), and event-free survival (P < .001 for younger and older) than RUNX1 wild-type patients. Because RUNX1 mutations were more common in older patients and almost never coexisted with NPM1 mutations, RUNX1 mutation–associated expression signatures were derived in older, NPM1 wild-type patients and featured upregulation of genes normally expressed in primitive hematopoietic cells and B-cell progenitors, including DNTT, BAALC, BLNK, CD109, RBPMS, and FLT3, and downregulation of promoters of myelopoiesis, including CEBPA and miR-223.
RUNX1 mutations are twice as common in older than younger patients with CN-AML and negatively impact outcome in both age groups. RUNX1-mutated blasts have molecular features of primitive hematopoietic and lymphoid progenitors, potentially leading to novel therapeutic approaches.
Chromosomal abnormalities are detected in 50–60% of patients with acute myeloid leukemia (AML) and are important predictors of prognosis and risk of relapse. The remaining patients, those with cytogenetically normal AML, are a seemingly homogeneous group that in fact consists of subsets of patients with distinct clinical outcomes. This heterogeneity is likely related to acquired gene mutations, as well as altered miRNA and gene-expression profiles, which occur within the group. The identification of recurrent molecular abnormalities has improved prognostication and provided insight into mechanisms of leukemogenesis for patients with cytogenetically normal AML, as well as led to the discovery of novel therapeutic targets. As the number of mutations continues to expand, bioinformatic algorithms that allow for integration of multiple markers will be necessary to provide optimal care for patients with this disease.
acute myeloid leukemia; mutational analysis; normal karyotype; prognostic markers
Increased ZAP-70 expression predicts poor prognosis in chronic lymphocytic leukemia (CLL). Current methods for accurately measuring ZAP-70 expression are problematic, preventing widespread application of these tests in clinical decision making. We therefore used comprehensive DNA methylation profiling of the ZAP-70 regulatory region to identify sites important for transcriptional control.
Patients and Methods
High-resolution quantitative DNA methylation analysis of the entire ZAP-70 gene regulatory regions was conducted on 247 samples from patients with CLL from four independent clinical studies.
Through this comprehensive analysis, we identified a small area in the 5′ regulatory region of ZAP-70 that showed large variability in methylation in CLL samples but was universally methylated in normal B cells. High correlation with mRNA and protein expression, as well as activity in promoter reporter assays, revealed that within this differentially methylated region, a single CpG dinucleotide and neighboring nucleotides are particularly important in ZAP-70 transcriptional regulation. Furthermore, by using clustering approaches, we identified a prognostic role for this site in four independent data sets of patients with CLL using time to treatment, progression-free survival, and overall survival as clinical end points.
Comprehensive quantitative DNA methylation analysis of the ZAP-70 gene in CLL identified important regions responsible for transcriptional regulation. In addition, loss of methylation at a specific single CpG dinucleotide in the ZAP-70 5′ regulatory sequence is a highly predictive and reproducible biomarker of poor prognosis in this disease. This work demonstrates the feasibility of using quantitative specific ZAP-70 methylation analysis as a relevant clinically applicable prognostic test in CLL.