CITED2 Facilitates Apoptosis Induced By Histone Deacetylase Inhibitor SAHA In Human Pediatric Pre-B Acute Lymphoblastic Leukemia Cells

Abstract Acute lymphoblastic leukemia (ALL) is the most common malignancy in childhood, representing 31% of all tumors, and about 85% of children with ALL have B-cell ALL. Although the survival rate is approaching 90%, ALL remains the main cause of death from disease in children and young adults. The activity of histone deacetylases (HDAC) in childhood ALL is increased compared with that in normal peripheral blood mononuclear cells or bone marrow cells. Treatment of mice engrafted with T or B-ALL cells with HDAC inhibitor (HDACi) increases the acetylation of Histone 3 and Histone 4 and prolongs survival of these mice. <>Vorinostat (Suberoylamilide Hydroxamic Acid, SAHA) was the first HDACi approved by the FDA for the treatment of refractory cutaneous T-cell lymphoma. Currently, several clinical trials are being conducted to evaluate its effects on other cancers, including ALL. However, some patients are resistant to HDACi therapy, and concerns regarding toxic side effects of HDACi exist due to the roles of HDACs in multiple pathways. Therefore, identification of new therapeutic targets is required which could improve the efficacy of HDACi by reducing the dose of HDACi administered without compromising the treatment benefits but alleviating the side effects of HDACi. <>CBP/p300-interacting transactivator with glutamic acid (E) and aspartic acid (D)–rich tail 2 (CITED2) is a cytokine-inducible gene that plays various roles during mouse development and, in particular, is essential for normal hematopoiesis. While the role of CITED2 in the pathogenesis of leukemia is currently unclear, dysregulation of CITED2 has been implicated in various types of leukemia, including ALL, in which downregulation of CITED2 is frequently observed. In this study, we tested the hypothesis that CITED2 may enhance the sensitivity of human pediatric pre-B ALL cells to HDACi SAHA. <>SAHA treatment of NALM-6 and 697 cells (human pediatric pre-B ALL cell lines) significantly induced apoptosis and cell cycle arrest in a dose dependent manner. The protein level of CITED2 was not affected by SAHA treatment. Although overexpression of CITED2 alone only slightly increased apoptosis, it significantly enhanced apoptosis resulted from SAHA treatment in both NALM-6 (15.1% versus 39.2%) and 697 cells (9.4% versus 14.6%) as assessed by annexin V/Propidium Iodide double staining and flow cytometry analysis (Figure 1). Accordingly, compared with control (i.e. NALM-6 cells transduced with GFP), overexpression of CITED2 also greatly reduced mitochondrial membrane potential of NALM-6 cells caused by SAHA treatment. To explore the potential mechanisms underlying enhanced apoptosis by overexpression of CITED2 in NALM-6 cells treated with SAHA, we determined the levels of pro- and anti- apoptotic proteins by Western blot and real-time quantitative PCR. We found that SAHA treatment increased the levels of pro-apoptotic molecules Bak, Puma, and Noxa, and decreased the levels of anti-apoptotic molecule Bcl-xL and apoptosis inhibitors XIAP and survivin. Importantly, overexpression of CITED2 markedly increased the protein levels of pro-apoptotic molecules Bak and Bim. Furthermore, knockdown of Bim by shRNA significantly attenuated apoptosis in Cited2 overexpressing NALM-6 cells treated with SAHA. Taken together, these results suggest that modulation of the CITED2 activity may confer its cooperative effect with SAHA in pre-B ALL cells and warrant future evaluation of such a combination in inducing apoptosis of primary ALL cells. Disclosures: No relevant conflicts of interest to declare.

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High incidence of potential p53 inactivation in poor outcome childhood acute lymphoblastic leukemia at diagnosis

Blood ◽

10.1182/blood.v87.3.1155.bloodjournal8731155 ◽

1996 ◽

Vol 87 (3) ◽

pp. 1155-1161 ◽

Cited By ~ 45

Author(s):

DI Marks ◽

BW Kurz ◽

MP Link ◽

E Ng ◽

JJ Shuster ◽

...

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Complete Remission ◽

Mononuclear Cells ◽

Lymphoblastic Leukemia ◽

Gene Mutations ◽

P53 Gene ◽

Leukemic Cells ◽

Childhood All ◽

P53 Gene Mutations ◽

P53 Inactivation

Previous studies have indicated that p53 gene mutations were an uncommon event in acute lymphoblastic leukemia (ALL) in children. In one series of 330 patients, p53 mutations were seen in fewer than 3%. We analyzed bone marrow mononuclear cells derived from 10 children with ALL at diagnosis who subsequently failed to achieve a complete remission or who developed relapse within 6 months of attaining complete remission for p53 gene mutations and mdm-2 overexpression. We found that three children had p53 gene mutations, and four overexpressed mdm-2. Also, experiments comparing relative levels of mdm- 2 RNA and protein in these patients demonstrated that mdm-2 overexpression can occur at the transcriptional and posttranscriptional level in primary leukemic cells. Although we were unable to link Waf-1 RNA expression with p53 status in childhood ALL, our data show potential p53 inactivation by multiple mechanisms in a large percentage of these patients and demonstrate that these alterations can be detected at diagnosis. Inactivation of the p53 pathway may, therefore, be important in children with ALL who fail to respond to treatment and may be useful for the early identification of children requiring alternative therapies.

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Cranial Irradiation Does Not Result in Pituitary-Gonadal Axis Dysfunction in Very Long-Term Male Survivors of Childhood Acute Lymphoblastic Leukemia.

Blood ◽

10.1182/blood.v114.22.989.989 ◽

2009 ◽

Vol 114 (22) ◽

pp. 989-989

Author(s):

Niels J. van Casteren ◽

Rob Pieters ◽

Gert Dohle ◽

Manita van Baalen ◽

Sebastian Neggers ◽

...

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Cranial Irradiation ◽

Gonadal Function ◽

Free T4 ◽

Childhood All ◽

Male Survivors ◽

Igf I

Abstract Abstract 989 Poster Board I-11 Introduction: One of the risks of childhood cancer treatment is fertility impairment later in life. In the past a large proportion of children with acute lymphoblastic leukemia (ALL) has received cranial irradiation as part of their treatment. The aim of this study was to evaluate whether cranial irradiation negatively affects pituitary regulated gonadal function in male survivors of childhood ALL. Patients and Methods: We examined gonadal function, including Inhibin B, LH, FSH, testosterone, and pituitary axis function by measuring TSH, Free-T4 and IGF-I levels in 89 long-term male survivors of childhood ALL after a median follow-up time of 19 year (range 7-34 years). Results: Twenty-nine out of 89 male ALL survivors received cranial irradiation. Inhibin, FSH, LH, Testosterone, testicular volume as well as TSH and Free-T4 levels were not different in the cranial irradiated group as compared to the non-irradiated group (table 1). In contrast, IGF-I levels were significantly lower in the cranial irradiated group. Survivors treated with total body irradiation or testicular irradiation had significantly decreased gonadal function based on hormone levels. Conclusions: These data show that, in contrast to the negative influence on the growth hormone axis, cranial radiotherapy as part of ALL treatment does not have a deleterious long-term effect on the hypothalamic–pituitary-gonadal axis or pituitary-thyroid axis. Disclosures: No relevant conflicts of interest to declare.

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Implication of Genetic Variations of Ikzf1, ARIDB5, and CEBPE Genes In the Risk of Childhood Acute Lymphoblastic Leukemia In Korea

Blood ◽

10.1182/blood.v116.21.3235.3235 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3235-3235

Author(s):

Dong Kyun Han ◽

Hee Nam Kim ◽

Min Ho Shin ◽

Minenori Eguchi-Ishimae ◽

Mariko Eguchi ◽

...

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Genetic Variations ◽

Childhood Acute Lymphoblastic Leukemia ◽

Asian Countries ◽

Childhood All ◽

Genomic Variations ◽

Genotype Frequencies ◽

The Impact

Abstract Abstract 3235 Background: Recent western studies have showed the implication of the germline genomic variations in IKZF1 gene at 7p12.2, ARIDB5 gene at 10q21.2, and CEBPE gene at 14q11.2 on the risk of childhood acute lymphoblastic leukemia (ALL); the most significant association was observed in the single nucleotide polymorphism (SNP) rs4132601 which located at 3' region of the IKZF1. IKZF1 plays important role in lymphocyte differentiation, proliferation and function, ARIDB5 in embryogenesis and growth regulation, and CEBPE in regulation of myelopoiesis. Genomic variants in these genes are therefore considered to be involved in transcriptional regulation and differentiation of B cell progenitors. However, there have been no reports on the role of germline variations in leukemogenesis of childhood ALL in Asian countries. The aim of this study is to show the impact of these genetic variants on childhood ALL in Korea. Patients and Methods: To examine the association between genetic variations (IKZF1 rs4132601, ARIDB5 rs7089424, and CEBPE rs2239633) and the risk of childhood ALL, we here analyzed 228 children with ALL and 508 healthy individuals in Korea. Results: In ARIDB5 rs7089424, TG and GG genotypes were significantly associated with a risk for ALL (odds ratio [OR], 1.63; 95% confidential interval [CI], 1.07–2.48; P=0.02 for TG genotype, OR, 2.69; 95% CI, 1.42–5.07; P=0.002 for GG genotype). The allele incidence of ARIDB5 rs7089424 was also significantly associated with a risk for ALL (OR, 1.66; 95% CI, 1.24–2.22; P=0.0006). CEBPE rs2239633 TT genotype showed a significant association with a decreased risk for ALL (OR, 0.54; 95% CI, 0.33–0.90; P=0.02 for TT genotype). The allele incidence of CEBPE rs2239633 was also associated with a decreased risk for ALL (OR, 0.77; 95% CI, 0.61–0.97; P=0.02). There was no significant association between IKZF1 rs4132601 polymorphism and a risk for ALL in this study. Conclusion: These results suggest that genomic variations of ARIDB5 and CEBPE may play an important role in the risk for childhood ALL in Korea, compared with findings from western countries showing a significant relation between IKZF1 and childhood ALL. Several factors should be considered to explain a discrepancy between our results and the previous studies, which include different genotype frequencies in polymorphisms and varied susceptibility to ALL in different ethnic groups. Further studies incorporating larger number of cases and analyzing other SNPs or other Asian countries are warranted in childhood ALL. Disclosures: No relevant conflicts of interest to declare.

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Chromothripsis-Mediated Structural Variations and Clonal Evolution In Recurrent Childhood High Hyperdiploid Acute Lymphoblastic Leukemia

Blood ◽

10.1182/blood.v122.21.233.233 ◽

2013 ◽

Vol 122 (21) ◽

pp. 233-233

Author(s):

Cai Chen ◽

Christoph Bartenhagen ◽

Michael Gombert ◽

Vera Okpanyi ◽

Vera Binder ◽

...

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Copy Number ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Clonal Evolution ◽

Copy Number Variations ◽

Chromosome 3 ◽

Structural Variations ◽

Childhood All ◽

A Genome

Abstract High hyperdiploid acute lymphoblastic leukemia (HeH-ALL) is characterized by 51-67 chromosomes and nonrandom gains of specific chromosomes (X, 4, 6, 10, 14, 17, 18, and 21). It presents the most frequent numerical cytogenetic alteration in childhood pre B-cell ALL occurring in 25-30% of cases. Recurrent disease will affect 15-20%. Pre-leukemic HeH clones are generated in utero, but cooperating oncogenic lesions are necessary for overt leukemia and remain to be determined. Recently, a phenomenon termed chromothripsis has been described in which massive structural variations occur in a single aberrant mitosis. Whole or partial chromosomes are shattered and some fragments are lost in the process of rejoining. Thus, characteristically, chromosomal copy numbers oscillate between two copy number states. Chromothripsis has been suggested to be a tumor-driving alteration that may be present in 2-3% of all human cancers. Its role as a potential cooperating or initiating lesion in HeH-ALL has not been determined. We applied state-of-the-art whole-genome next-generation-sequencing to analyze structural variations in six pediatric patients with recurrent HeH-ALL. Matched sample sets taken at diagnosis, remission and/or relapse were compared. Paired end sequencing was carried out on a Genome Analyzer IIx or a HiSeq 2000 (Illumina), respectively. Reads were aligned against the human reference genome (GRCh37) using BWA. Translocations were detected by GASV. Copy number variations were analyzed by FREEC. Structural variations were validated by PCR/Sanger sequencing and FISH. Of the six patients analyzed, five harbored on average one interchromosomal translocation or intrachromosomal inversion, but one patient presented with massive genomic rearrangements (Figure). These affected chromosome 3, 11, 12 and 20. Ten copy number shifts on chromosome 3 oscillating between two copy number states (2 and 3) indicated that these rearrangements were caused by chromothripsis. Breakpoint sequencing revealed that one of the identified translocations (t(12;20)(p13.1;p12.3)), was indeed a three-loci-rearrangement composed of small fragments derived from chromosomes 3, 12 and 20. Characteristically for chromothripsis, the breakpoints clustered closely. Three breakpoints separated by 224 bp and 64 kb were located in the transducin (beta)-like X-linked receptor 1 (TBL1XR1) gene. Other genes repeatedly targeted included the MACRO domain-containing protein 2 (MACROD2) gene (a deacetylase involved in deacetylation of lysine residues in histones and other proteins), the KIAA1467 gene (a transmembrane protein of the integrin alpha FG-GAP repeat containing 3 (ITFG3) family), and a novel regulatory lincRNA (ENSG00000243276). MACROD2 was previously observed as a target of chromothripsis in a colorectal carcinoma. Thus, the characterized breakpoints may identify fragile genomic sites prone to chromothriptic rearrangement. DNA repair was effectuated by non-homologous-end-joining as typical addition of non-template nucleotides with microhomologies of two to four nucleotides at the breakpoints demonstrated. Copy number profiles of this patient showed that at least two distinct leukemic clones could be identified at diagnosis. One had acquired chromothriptic alterations and presented the dominant clone at relapse indicating chemotherapy resistance and tumor-driving potential. Prior whole-exome sequencing did not reveal mutations in known oncogenes or tumor suppressor genes. Therefore, loss of function or expression of genes affected by chromosomal rearrangements, such as TBL1XR1 that is recurrently mutated in childhood ALL with ETV6-RUNX1 translocation, may account for the tumor-driving effect. All leukemic cells at diagnosis showed conformity concerning number and pattern of whole chromosome gains demonstrating that chromothripsis was not an initiating oncogenic event, but occurred secondary to high hyperdiploidy. Further aberrations (t(4;7), loss of 4q) were gained by the chromothriptic clone and could be detected by FISH in minor subclones pointing at ongoing clonal evolution. Taken together, our study reveals chromothripsis as a novel assisting and tumor-driving lesion in HeH ALL. Chromothripsis in HeH-ALL. Copy number variations and translocations at diagnosis (left) and relapse (right). (magenta: chromothriptic translocations; green: other translocations) Disclosures: No relevant conflicts of interest to declare.

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Aggravated Bone Density Decline after Symptomatic Osteonecrosis in Children with Acute Lymphoblastic Leukemia

Blood ◽

10.1182/blood.v124.21.2260.2260 ◽

2014 ◽

Vol 124 (21) ◽

pp. 2260-2260

Author(s):

Marissa den Hoed ◽

S.M.F. Pluijm ◽

Mariël L. Te Winkel ◽

Hester A. de Groot-Kruseman ◽

Marta Fiocco ◽

...

Keyword(s):

Bone Mineral Density ◽

Acute Lymphoblastic Leukemia ◽

Side Effects ◽

Bone Mineral ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Bone Destruction ◽

Mineral Density ◽

Pediatric All ◽

Cessation Of Treatment

Abstract Background: Osteonecrosis (ON) and decline of bone mineral density (BMD) are serious side effects during and after treatment of childhood acute lymphoblastic leukemia (ALL). It is unknown whether ON and low BMD co-occur in the same patients, and whether these two osteogenic side effects can influence each other’s development during pediatric ALL treatment. Methods: BMD and the incidence of symptomatic ON were prospectively assessed in 466 patients with ALL (4-18 years of age) treated according to the dexamethasone-based Dutch Child Oncology Group-ALL9 protocol. Symptomatic ON was defined as persistent pain in arms or legs not caused by vincristine administration, and confirmed by magnetic resonance imaging. Bone mineral density of the lumbar spine (BMDLS) (n=466) and of the total body (BMDTB) (n=106) were measured by dual X-ray absorptiometry at ALL diagnosis, after 32 weeks of treatment, at cessation of treatment (109 weeks) and 1 year after cessation of treatment. BMD was expressed as age-matched and gender-matched standard deviation scores (SDS; Z-score). Multivariate linear mixed models were adjusted for age at diagnosis. Results: Thirty patients (6.4%) suffered from ON. At cessation of treatment, mean BMDLS was -1.28 SDS (SD: 1.27, n=332; p<0.01) and BMDTB was -0.74 SDS (SD: 1.29, n=65; p<0.01) lower in ALL patients compared to their healthy peers. At baseline, BMDLS and BMDTB did not differ between patients who developed or who did not develop ON (mean BMDLS ON+: -0.90 vs. ON-: -1.14, p=0.36; mean BMDTB ON+: 0.07 vs. ON-: 0.25 p=0.65). At cessation of treatment, patients with ON seem to have a trend for a lower mean BMDLS (ON+: -1.68 vs. ON-: -1.31, p=0.18) and they have a lower mean BMDTB (ON+: -1.91 vs. ON-: -0.59, p=0.01) than patients without ON. Multivariate analyses showed that BMDTB change during follow-up was significantly different for patients with ON than without ON (interaction group time, p=0.04). Between BMD measurements before and after the diagnosis, patients with ON seemed to have a more rapid decline of BMDTB than in patients of the same age without ON (mean BMDTB difference -1.13 vs. -0.62, p=0.10). Conclusion: We conclude that symptomatic ON and low BMD during antileukemic treatment co-occur in pediatric ALL patients. BMD status at ALL diagnosis does not seem to precede ON. However, the development of ON seems to aggravate BMD decline during antileukemic treatment, most likely due to bone destruction and the advised physical immobilization. Disclosures No relevant conflicts of interest to declare.

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Dnmt3a Haploisufficiency Cooperates with Oncogenic Kras to Promote an Early-Onset T-Cell Leukemia

Blood ◽

10.1182/blood.v128.22.2729.2729 ◽

2016 ◽

Vol 128 (22) ◽

pp. 2729-2729

Author(s):

Yuan-I Chang ◽

Guangyao Kong ◽

Jing Zhang ◽

Erik A. Ranheim

Keyword(s):

T Cell ◽

Dna Methyltransferase ◽

Bone Marrow Cells ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Myeloproliferative Neoplasm ◽

Dominant Negative ◽

Dependent Manner ◽

Myeloid Malignancies ◽

Dose Dependent

Abstract Recent whole genome/exome sequencing efforts in myeloid malignancies identified that mutations in DNA methyltransferase 3A (DNMT3A) are prevalent in acute myeloid leukemia (AML). In addition, DNMT3A mutations are also identified in various T cell malignancies. Of note, DNMT3A mutations are typically heterozygous and some WT DNMT3A functions thus remain in this state. However, the predominant DNMT3A R882 mutations, which locate in the catalytic domain, seem to inhibit the methyltransferase activity of the remaining WT DNMT3A due to its dominant-negative function (Yang L, Rau R, Goodell MA, Nat. Rev. Cancer 15: 152-165, 2015). COSMIC database analysis reveals different prevalence of DNMT3A R882 mutations in various hematopoietic malignancies. Approximately 60% of DNMT3A mutations in AML are R882 mutations, while the frequency of R882 mutations drops to ~40% in myelodysplastic syndrome (MDS) and myeloproliferative neoplasm (MPN). In contrast, the frequency of R882mutations is less than 25% in T-cell acute lymphoblastic leukemia (T-ALL). The significantly different frequencies of DNMT3A R882 mutations in AML versus T-ALL inspired us to investigate whether downregulation of DNMT3A regulates malignancies of different lineages in a dose-dependent manner. We previously showed that Dnmt3a-/- promotes MPN progression in KrasG12D/+ mice and ~1/3 compound mice develop AML-like disease (Chang et al. Leukemia 29: 1847-1856, 2015). Here, we generated KrasG12D/+; Dnmt3afl/+; Mx1-Cre mice to determine how Dnmt3a haploisufficiency affects KrasG12D/+-induced leukemogenesis. After pI-pC injections to induce Mx1-Cre expression, primary KrasG12D/+; Dnmt3a+/- mice died quickly as primary KrasG12D/+ mice; the survival rates of these two groups of animals were not significantly different. However, in a competitive transplant setting, recipients transplanted with KrasG12D/+; Dnmt3a+/- bone marrow cells displayed a significantly shortened survival than recipients with KrasG12D/+ cells. Moreover, all of the recipients with KrasG12D/+; Dnmt3a+/- cells developed a lethal T-ALL without significant MPN phenotypes, while ~20% of recipients with KrasG12D/+ cells developed MPN with or without T-ALL. This is in sharp contrast to the recipients with KrasG12D/+; Dnmt3a-/- cells, in which ~60% developed a lethal myeloid malignancy (MPN or AML). Our data suggest that in the context of oncogenic Kras, loss of Dnmt3a promotes myeloid malignancies, while Dnmt3a haploisufficiency induces T-ALL. This dose-dependent phenotype is highly consistent with the prevalence of DNMT3A R882 mutations in AML versus T-ALL in human. We are currently investigating the underlying mechanisms. Disclosures No relevant conflicts of interest to declare.

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The Frequencies of ETV6-RUNX1 Fusion and Hyperdiploidy (>50 chromosomes) in Children with Acute Lymphoblastic Leukemia Are Lower in Far East Than the West..

Blood ◽

10.1182/blood.v114.22.3064.3064 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3064-3064

Author(s):

Der-Cherng Liang ◽

Lee-Yung Shih ◽

Chao-Ping Yang ◽

Iou-Jih Hung ◽

Hsi-Che Liu ◽

...

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Meta Analysis ◽

Far East ◽

Hong Kong Chinese ◽

Event Free Survival ◽

The West ◽

Childhood All ◽

Free Survival

Abstract Abstract 3064 Poster Board III-1 Both ETV6-RUNX1 (TEL-AML1)fusion and hyperdiploidy (>50 chromosomes) of lymphoblasts are favorable outcome predictors in childhood acute lymphoblastic leukemia (ALL). In 433 children with ALL diagnosed at our hospitals between 1997 and 2007 in Taiwan, the frequency of ETV6-RUNX1 fusion was 15.8%, and the frequency of hyperdiploidy (>50 chromosomes) was 14.1%, both were lower than those of the West. While ETV6-RUNX1 fusion had borderline favorable impact on outcome (p=0.053-0.061), hyperdiploidy showed significant favorable impact on event-free survival (91.1% vs 76.6 %, p= 0.016) in our patients. A meta-analysis from literature enrolled reports in which the case numbers and frequency of ETV6-RUNX1 fusion or hyperdiploidy in childhood ALL were described. It revealed that the frequency of ETV6-RUNX1 fusion in childhood ALL in Far East (Japan, Korea, Hong Kong, Chinese in Singapore, and Taiwan) was 14.2% (127/893, range 10-17%), significantly lower than 21.8% (152/697, range 19-27%) in the West (USA, Germany, Italy, France and Chile) (p < 0.0001). The frequency of hyperdiploidy in Japan and Taiwan was 15.2% (140/921, range 13-20%), significantly lower than 31.6% in the West (977/3,158, range 19-34%) (USA, UK and Germany) (p < 0.0001). So far as we know, there were several articles, including ours, addressing that the frequency of ETV6-RUNX1 fusion in childhood ALL was lower in a Far East country. This is the first meta-analysis to demonstrate that the frequency of ETV6-RUNX1 fusion in childhood ALL in Far East was lower than that in the West. There was no report on that the frequency of hyperdiploidy in Far East was lower than that in the West. This is also the first meta-analysis to demonstrate that the frequency of hyperdiploidy in childhood ALL in Far East is significantly lower than that in the West. The nature of these differences, probably due to racial, needs further study. In Far East, with both a lower frequency of ETV6-RUNX1 fusion, and a lower frequency of hyperdiploidy, it warrants renewed effort to cure a higher proportion of children with ALL. Disclosures No relevant conflicts of interest to declare.

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Anti-Leukemic Property of Sulphoraphane In Precursor B Cell Acute Lymphoblastic Leukemia

Blood ◽

10.1182/blood.v116.21.3974.3974 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3974-3974

Author(s):

Koramit Suppipat ◽

Xiao Zhu ◽

Chun Shik Park ◽

H. Daniel Lacorazza

Keyword(s):

Acute Lymphoblastic Leukemia ◽

B Cells ◽

B Cell ◽

Cell Line ◽

Cell Lines ◽

Lymphoblastic Leukemia ◽

Annexin V ◽

Dependent Manner ◽

Carcinogenic Activity ◽

Childhood All

Abstract Abstract 3974 Acute lymphoblastic leukemia (ALL) is the most common form of hematologic malignancy in children. In spite of significant advances achieved in the treatment of childhood ALL, one fifth of these patients still relapse after the standard treatment. Moreover, relapse ALL is the second most common cause of cancer-related deaths in children. The development of novel therapies is prevented by a limited understanding of the exact pathobiology. There are emerging evidences that the transcription factor KLF4 has a tumor suppressor property in ALL. Recently, a gene expression classifier study in pediatric precursor B-cell ALL (pre-B ALL) showed that KLF4 expression was significantly reduced in high risk ALL patients with positive MRD after induction. This finding suggests a possible role of this cell cycle inhibitor on the development, expansion and drug-resistant of leukemic cells. Several studies demonstrate that overexpression of KLF4 in normal B cells and BCR transformed B cells show increased apoptosis and reduced proliferation. Furthermore, we recently described that KLF4 inhibits proliferation of naïve lymphocytes by activating p21 (Yamada, et al, 2009). Sulphoraphane (SF; 4-methylsulfonylbutyl isothiocyanate) is a dietary compound derived from Cruciferae vegetables with anti-carcinogenic activity in colon cancer by upregulating KLF4 and p21 among other genes. Thus, we hypothesized that SF could also exhibit anti-leukemic activity in human-derived acute lymphoblastic leukemia cells via the activation of KLF4. The pre-B ALL cell lines (Nalm6, REH, RS-4, SUP-B15) and an EBV transformed B cell line were treated with different concentrations of SF (0-40 μM) for 24–48 hours. Then, cell number was estimated using an ATP-based viability method. Flow cytometric analysis of ANNEXIN-V/7-AAD binding as well as CFSE dilution was used to measure apoptosis and proliferation respectively. We found that SF induced cytotoxicity in Nalm-6, REH and RS-4 cell lines in a dose and time dependent manner. This cytotoxic effect was less pronounced in EBV-transformed B cell line. SF treatment led to increased ANNEXIN-V and 7-AAD positive cells (82% apoptotic cells in SF-treated versus 9% in DMSO control). Further, SF-treated cells displayed significantly less proliferation in comparison to DMSO controls thus suggesting that SF inhibits cellular proliferation. Preliminary data also suggest that SF-mediated apoptosis is caused by upregulation of KLF4. In conclusion, Sulphoraphane exhibits an anti-leukemic property by inducing apoptosis and abrogating proliferation in pre-B ALL cell lines. Thus, sulphoraphane could potentially be used as an adjunctive therapy in a subgroup of pre-B ALL patients who have decreased expression of KLF4. Disclosures: No relevant conflicts of interest to declare.

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Identification of JAK1 Mutation In 40 Cases of Adult Acute T Lymphoblastic Leukemia

Blood ◽

10.1182/blood.v116.21.4652.4652 ◽

2010 ◽

Vol 116 (21) ◽

pp. 4652-4652

Author(s):

Aining Sun ◽

Wenjuan Wang ◽

Guanghua Chen ◽

Wu Depei ◽

Suning Chen ◽

...

Keyword(s):

Bone Marrow ◽

Acute Lymphoblastic Leukemia ◽

T Cell ◽

Mononuclear Cells ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Amino Acid Sequences ◽

Insertion Mutation ◽

Newly Diagnosed ◽

Cell Acute Lymphoblastic Leukemia

Abstract Abstract 4652 Objective This study was purposed to analyze the mutations of JAK1 in bone marrow cells from adult patients with newly-diagnosed T cell acute lymphoblastic leukemia (T-ALL). Methods The entire coding sequence of JAK1 in bone marrow mononuclear cells (MNCs) from 40 adult T cell ALL patients were screened by polymerase chain reaction (PCR) and direct sequencing, then the clinical features of JAK1 mutation positive patients were analyzed. Results JAK1 mutations were identified in 5%(2/40) patients, one is point mutation, the other is insertion mutation, resulting in changes in amino acid sequences, and the two types of mutations are different from those mutations found before. Conclusion The JAK1 mutations were found in about 5% newly-diagnosed T cell acute lymphoblastic leukemia, which was lower than those report abroad. Disclosures: No relevant conflicts of interest to declare.

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JAK2 Inhibition with TG101348 Inhibits Monosomy 7 Myelodysplastic Syndromes (MDS) Bone Marrow Cells In Vitro: a Potential Targeted Therapy for Monosomy 7 MDS

Blood ◽

10.1182/blood.v116.21.973.973 ◽

2010 ◽

Vol 116 (21) ◽

pp. 973-973 ◽

Cited By ~ 2

Author(s):

Matthew J. Olnes ◽

Andrea Poon ◽

Zachary Tucker ◽

Neal S. Young ◽

Elaine M Sloand

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Myelodysplastic Syndromes ◽

Mononuclear Cells ◽

Bone Marrow Cells ◽

Conflicts Of Interest ◽

Myeloid Cells ◽

Dependent Manner ◽

Monosomy 7

Abstract Abstract 973 The myelodysplastic syndromes (MDS) are bone marrow disorders characterized by cytopenias and a variable risk of progression to acute myeloid leukemia (AML). Monosomy 7 is the second most common cytogenetic abnormality in MDS, and the most frequent karyotypic aberration occurring in aplastic anemia patients following immunosuppressive therapy. Monosomy 7 MDS carries a particularly poor prognosis, with patients manifesting severe cytopenias and a high propensity to develop treatment-refractory AML. There are currently no targeted therapies for this disorder. We previously reported that monosomy 7 bone marrow mononuclear cells (BMMNCs) express high levels of a differentiation-defective granulocyte colony stimulating factor (G-CSF) receptor isoform (IV), an alternative splice variant that exhibits constitutive signaling through the JAK-2 and STAT-1 pathway, while levels of STAT-3 and -5 are unchanged (Sloand et al, PNAS, 2006, 103:14483). As a result, the cell's ability to differentiate is limited, while its ability to proliferate remains intact. Here we examine the effects of the highly selective JAK2 inhibitor TG101348 on monosomy 7 aneuploidy in BMMNCs, as well as the activity of this compound on CD34+ stem cells and CD13+ myeloid cells in culture, and on the JAK-2 signaling apparatus. Incubation of BMMNCs with TG101348 for 5 days significantly decreased absolute numbers of monosomy 7 aneuploid cells in a concentration dependent manner versus vehicle- treated controls (0.187 × 106 vs 1.08 × 106, P=0.007), while diploid cell numbers remained stable (0.338 × 106 vs 0.213 × 106, P=0.50). Flow cytometry experiments demonstrated that incubation with increasing concentrations of TG101348 decreased the absolute number of CD34+CD13- stem cells, and increased numbers of more differentiated CD34-CD13+ myeloid cells, with median CD34+/CD13+ ratios of 6.547 and 2.216 for cells treated with vehicle and 100 nM TG101348, respectively. By immunoblot, STAT-1 protein expression in monosomy 7 BMMNCs treated with 1uM TG101348 was decreased relative to vehicle- treated controls, while there was no difference in STAT-3 and STAT-5 levels. Thus TG101348 decreases monosomy 7 MDS blasts in vitro through inhibition of JAK-2/STAT-1 signaling, a finding that warrants further study of this agent in clinical trials for patients with monosomy 7 MDS and AML. Disclosures: No relevant conflicts of interest to declare.

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