Down's syndrome with acute lymphoblastic pediatric leukemia (DS-ALL)
Ontology highlight
ABSTRACT: DS-ALL is a highly heterogeneous disease with predominance of an aberrant exp. of CRLF2 cooperating with mutated JAK2 Acute lymphoblastic pediatric leukemia specimens of Down's syndrome are examined for gene expression profiles and specific genetic aberrations. Gene expression profiling and specific genetic variation analysis identify novel pathways involved in DS-ALL pathogenesis.
Project description:DS-ALL is a highly heterogeneous disease with predominance of an aberrant exp. of CRLF2 cooperating with mutated JAK2; Acute lymphoblastic pediatric leukemia specimens of Down's syndrome are examined for gene expression profiles and specific genetic aberrations. Gene expression profiling and specific genetic variation analysis identify novel pathways involved in DS-ALL pathogenesis. Experiment Overall Design: Gene expression profile analysis and specific genetic data are integrated to find characteristics of DS-ALL's
Project description:Patients with Down syndrome (DS) and acute lymphoblastic leukemia (ALL) have distinct clinical and biological features. Whereas most DS-ALL cases lack the sentinel cytogenetic lesions that guide risk assignment in childhood ALL, JAK2 mutations and CRLF2 overexpression are highly enriched. To further characterize the unique biology of DS-ALL, we performed genome-wide profiling of 58 DS-ALL and 35 non-Down syndrome (NDS) ALL cases by DNA copy number, loss of heterozygosity, gene expression, and methylation analyses. We report novel deletions within the 6p22 histone gene cluster as significantly more frequent in DS-ALL, occurring in 12 DS (24%) and only a single NDS case (3%) (Fisher’s exact p = 0.013). Homozygous deletions yielded significantly lower histone expression levels, and were associated with higher methylation levels, distinct spatial localization of methylated promoters, and enrichment of highly methylated genes for specific pathways and transcription factor binding motifs. Gene expression profiling identified CRLF2 overexpression in nearly half DS-ALL cases, and supervised analysis identified an associated 39-gene signature. However, no expression signature was identified for DS-ALL overall, nor for histone status, suggesting that DS-ALL constitutes several, heterogeneous molecular entities. Characterization of pathways associated with histone deletions and high CRLF2 expression may identify opportunities for novel targeted interventions. This SuperSeries is composed of the SubSeries listed below.
Project description:CRLF2 rearranged Ph-like ALL cells are driven by oncogenic cytokine receptor signaling mediated by CRLF2 and JAK2. MHH-cALL4 cells were treated with ruxolotinib (JAK2 inhibitor) to provide insight into mechanisms of drug resistance.
Project description:Deregulated expression of cytokine receptor gene, CRLF2, is involved in lymphoid transformation in B-cell precursor acute lymphoblastic leukemia We report two novel, cryptic chromosomal abnormalities in precursor B-cell acute lymphoblastic leukemia (BCP-ALL): a translocation, either t(X;14)(p22;q32) or t(Y;14)(p11;q32), in 33 patients and an interstitial deletion, either del(X)(p22.33p22.33) or del(Y)(p11.32p11.32), in 64 patients, involving the pseudoautosomal region (PAR1) of the sex chromosomes. The incidence of these abnormalities was 5% in childhood ALL (0.8% with the translocation, 4.2% with the deletion). Patients with the translocation were older (median age 16 years), whilst the patients with the deletion were younger (median age 4 years). The two abnormalities result in deregulated expression of the cytokine receptor, cytokine receptor-like factor 2, CRLF2 (also known as thymic stromal-derived lymphopoietin receptor, TSLPR). Over-expression of CRLF2 was associated with activation of the JAK-STAT pathway in cell lines and transduced primary B-cell progenitors, sustaining their proliferation and indicating a causal role of CRLF2 over-expression in lymphoid transformation. In Down Syndrome (DS) ALL and two non DS BCP-ALL cell lines, CRLF2 deregulation was associated with mutations of the JAK2 pseudokinase domain suggesting oncogenic cooperation, as well as highlighting a link between non DS ALL and JAK2 mutations. Keyword(s): Global copy number analysis using Agilent oligonucleotide arrays
Project description:Deregulated expression of cytokine receptor gene, CRLF2, is involved in lymphoid transformation in B-cell precursor acute lymphoblastic leukemia We report two novel, cryptic chromosomal abnormalities in precursor B-cell acute lymphoblastic leukemia (BCP-ALL): a translocation, either t(X;14)(p22;q32) or t(Y;14)(p11;q32), in 33 patients and an interstitial deletion, either del(X)(p22.33p22.33) or del(Y)(p11.32p11.32), in 64 patients, involving the pseudoautosomal region (PAR1) of the sex chromosomes. The incidence of these abnormalities was 5% in childhood ALL (0.8% with the translocation, 4.2% with the deletion). Patients with the translocation were older (median age 16 years), whilst the patients with the deletion were younger (median age 4 years). The two abnormalities result in deregulated expression of the cytokine receptor, cytokine receptor-like factor 2, CRLF2 (also known as thymic stromal-derived lymphopoietin receptor, TSLPR). Over-expression of CRLF2 was associated with activation of the JAK-STAT pathway in cell lines and transduced primary B-cell progenitors, sustaining their proliferation and indicating a causal role of CRLF2 over-expression in lymphoid transformation. In Down Syndrome (DS) ALL and two non DS BCP-ALL cell lines, CRLF2 deregulation was associated with mutations of the JAK2 pseudokinase domain suggesting oncogenic cooperation, as well as highlighting a link between non DS ALL and JAK2 mutations. Keyword(s): Global copy number analysis using Agilent oligonucleotide arrays DNA copy number analysis of 16 acute lymphoblastic leukaemia samples (13 diagnostic, 1 diagnostic and relapse pair and 2 cell-lines) was performed using Agilent 244K and 105K custom microarrays. These samples were hybridised against gender matched reference DNA.
Project description:Deregulated expression of the type I cytokine receptor, CRLF2 (CRLF2-d), is observed in 5-15% of B-cell precursor acute lymphoblastic leukaemia (BCP-ALL), is associated with activation of the JAK/STAT pathway and has an inferior outcome compared to those with good risk cytogenetics. We aimed to determine the clinical and genetic landscape of CRLF2-d ALL using genomic approaches including karyotyping, fluorescence in situ hybridisation, whole genome and whole exome sequencing. The clinical and demographic features of CRLF2-d patients were characteristic of BCP-ALL. Patients with IGH-CRLF2 were older than those with P2RY8-CRLF2 (4yrs v 14yrs, p<0.001), while the incidence of CRLF2-d among Down syndrome patients was high (31%). CRLF2-d co-occurred with established primary chromosomal rearrangements but the majority (72%) had B-other ALL. The copy number alteration (CNA) profile was similar to B-other ALL, although CRLF2-d patients harboured higher frequencies of IKZF1 (43% v 23%) and BTG1 deletions (15% v 2%). There were differences in the CNA profile between IGH-CRLF2 and P2RY8-CRLF2 patients: deletions of IKZF1 (71% v 33% p<0.001), BTG1 (31% v 9%, p=0.004) and ADD3 (46% v 13%, p=0.008). A novel gene fusion, USP9X-DDX3X was discovered in 18% of CRLF2-d ALL. Pathway analysis of the mutational profile revealed novel involvement of the focal adhesion pathway. In conclusion, CRLF2-d defines a discrete subtype of B-other ALL, characterised by a distinctive profile of cooperating abnormalities, which drive leukaemogenesis in conjunction with CRLF2-d. Although the functional relevance of many of these abnormalities are unknown, they likely activate alternative pathways, which may represent novel therapeutic targets. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from cryopreserved diagnostic bone marrow or remission bone marrow.
Project description:Gene expression profiling was performed to define transcriptional programs associated with response to type II JAK2 inhibitor NVP-CHZ868 alone or in combination with dexamethasone in vitro and in vivo. MHH-CALL4 cells harboring a CRLF2 rearrangement and JAK2 I682F mutation were treated with vehicle, CHZ868, dexamethasone, or CHZ868 + dexamethasone combination for 12 hours in triplicate. RNA was then extracted for hybridization on Affymetrix microarrays. CRLF2+ patient-derived xenografts (05-412, 05-440, and 05-537) were treated in vivo for 3 days with vehicle, CHZ868, dexamethasone, or CHZ868 + dexmathasone combination for 3 days and then sacrificed. Transcriptional profiling was performed on unselected splenocytes from these animals.
Project description:Background Children with Down Syndrome have an augmented risk for B-cell acute lymphoblastic leukaemia (DS-ALL), which is associated with a survival lower than in non-DS ALL, due to increased chemotherapy-related toxicity and a higher relapse rate, thus demanding new tailored therapeutic strategies. Cytogenetic abnormalities common in childhood ALL are less frequent in DS-ALL, while alterations in CRLF2 and IKZF1 genes are increased. Aim of the study was to evaluate in DS-ALL children the incidence and prognostic value of the Philadelphia Chromosome-Like (Ph-like) status and the “IKZF1plus” profile, both associated with poor outcome in non-DS ALL and therefore introduced in current therapeutic protocols for BCP-ALL. Method Seventy DS-ALL patients at diagnosis treated in Italian centres from 2000 to 2014 were evaluated for their cytogenetic status, including the Ph-like ALL profile, while the IKZF1plus feature was investigated in a larger cohort of 134 patients treated in Italian and German centres from 2000 to 2011. Findings Forty-six out of 70 (65•7%) AIEOP DS-ALL patients displayed the Ph-like ALL gene expression signature, mostly characterized by CRLF2 (n=33) and IKZF1 (n=16) alterations (13 had both alterations); only one case was positive for an ABL-class and one for a PAX5 fusion gene. In the Italian and German joint cohort, we observed 35•6% patients positive for P2RY8::CRLF2 fusion, 24•8% for IKZF1 deletion and 18% for IKZF1plus feature. Unexpectedly, a higher IKZF1 expression and activity were observed in IKZF1plus than IKZF1 wt DS-ALL patients. Ph-like signature and IKZF1 deletion were associated with poor outcome, which further worsens when IKZF1 deletion was co-occurring with P2RY8::CRLF2, qualifying for the IKZF1plus definition. Interpretation These subgroups, which for the most part are not associated with other high risk features, need new and tailored therapeutic strategies, not only focussed on the use of drugs that restore IKZF1 function.
Project description:Children with Down Syndrome (DS) are prone to development of high risk B-cell precursor ALL (DS-ALL) that differs genetically from most sporadic pediatric ALLs. Increased expression of CRLF2, the receptor to thymic stromal lymphopoietin (TSLP) characterizes about half of DS-ALLs and also a subgroup of sporadic “Philadelphia-like ALLs”. To understand the pathogenesis of relapsed DS-ALL we performed integrative genomic analysis of 25 matched diagnosis remission and relapse DS-ALLs. We found that the CRLF2 rearrangements are early events during DS-ALL evolution and generally stable between diagnoses and relapse. Secondary activating signaling events in JAK-STAT/RAS pathway were ubiquitous but highly redundant between diagnosis and relapse, suggesting that signaling is essential but that no specific mutations are “relapse driving”. We further found that activated JAK2 may be naturally suppressed in 25% of CRLF2 positive DS-ALL by loss-of-function aberrations in USP9X, a deubuitinase previously shown to stabilize the activated phosphorylated JAK2. Interrogation of large ALL genomic databases extended our findings up to 25% of CRLF2 positive, “Ph like” ALLs. Pharmacological or genetic inhibition of USP9X as well as treatment with low-dose Ruxolitinib enhanced the survival of pre-B ALL cells overexpressing mutated JAK2. Thus, somehow counterintuitive, we found that suppression of JAK-STAT “hyper-signaling” may be beneficial to leukemic B cell precursors. This and the reduction of JAK mutated clones at relapse suggest that the therapeutic effect of JAK specific inhibitors may be limited. Rather, combined signaling inhibitors or direct targeting of the TSLP receptor may be a useful therapeutic strategy for DS-ALL.
Project description:The goal of this study is to define a gene expression signature unique to DS-AMKL (acute megakaryoblastic leukemia or FAB M7 leukemia). A similar study was done previously, but using unfractionated patient leukemic samples. In this study, we sorted megakaryocytic leukemia blasts from patients and then compared their gene expression signatures to those from similarly sorted blasts from patients with non-DS AMKL. This allowed us to identify a gene expression signature more unique to DS-AMKL samples.