Single-cell analysis identifies CRLF2 rearrangements as both early and late events in Down syndrome and non-Down syndrome acute lymphoblastic leukaemia

Potter, Nicola; Jones, Lisa; Blair, Helen J.; Strehl, Sabine; Harrison, Christine J.; Greaves, Mel; Kearney, Lyndal; Russell, Lisa J.

doi:10.1038/s41375-018-0297-4

Cited by 26 publications

(24 citation statements)

References 57 publications

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“…In DS-ALL, recent studies of sub-clonal and single-cell evolution of changes in leukemic ALL blasts have identified signaling activators (CRFL2-rearrangements, JAK2 mutations, RAS-MAPK mutations and iAMP21) as frequent events in primary and relapsed leukemic blasts (20,21,38). In particular, JAK2 and RAS mutations were found to be both acquired and lost in relapse samples in a mutually exclusive manner (20,21).…”

Section: Discussionmentioning

confidence: 99%

RAS activation via CRLF2 signaling is a widespread mechanism in Down syndrome acute lymphoblastic leukemia regardless of RAS mutations

Koschut

Ray

et al. 2020

Preprint

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Background: Down syndrome acute lymphoblastic leukemia (DS-ALL) is characterized by the high frequency of CRLF2-rearrangements, JAK2-mutations, or RAS-pathway mutations. Intriguingly, JAK2 and RAS mutations are mutually exclusive in leukemic sub-clones, causing dichotomy in therapeutic target choices.Results: Here we show that in primary leukemic cells from DS-ALL, in the absence of RAS-mutations, wild-type (wt)RAS is active, and/or can be induced by the physiological ligand TSLP of the transmembrane-receptor CRLF2. We show active/inducible RAS in 14/20 (70%) of primary DS-ALL samples analyzed, 8 of which had no RAS-mutations, but 75% of those had either mutated or hyperphosphorylated JAK2. No wtRAS cases with mutated/hyperphosphorylated JAK2 were observed that lacked activated RAS protein. We prove in a cell model that elevated CRLF2 in combination with constitutionally active JAK2 is sufficient to activate wtRAS. We show that TSLP boosts the direct binding of active PTPN11 to wtRAS. Pre-inhibition of RAS or PTPN11, but not of PI3K or JAK signaling, prevented TSLP-induced RAS-GTP boost.Using multivariate-clustering based on RAS-activity/inducibility we show significant separation between standard-risk and high-risk DS-ALL groups. Cox proportional-hazards model showed proteinactivity (but not mutation status) as independently predictive of outcome. Conclusions:Our data indicate that RAS protein activity levels (and not JAK2/RAS mutation profiles), are predictive of outcome. Importantly, our data suggest that inhibition of RAS and direct RASpathway components should be combined with PI3K/mTOR and/or JAK2 inhibitors for high-risk cases.Therapeutically this is relevant for >75% of DS-ALL and our additional data suggest that it warrants further investigation in high-risk non-DS-ALL.wtRAS activation is frequent in DS-ALL

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Section: Discussionmentioning

confidence: 99%

RAS activation via CRLF2 signaling is a widespread mechanism in Down syndrome acute lymphoblastic leukemia regardless of RAS mutations

Koschut

Ray

et al. 2020

Preprint

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“…Acute lymphoblastic leukemia (ALL) is the most common type of leukemia, and is characterized by uncontrolled proliferation of immature lymphoid cells [ 1 , 2 ]. Despite significant advances over the past few decades to develop treatments for ALL, ~ 25% of children and half of the adults do not respond to chemotherapy or relapse [ 3 – 5 ]. At present, the available treatment options for ALL include chemotherapy, antibody therapy and allogeneic bone marrow transplantation, and the treatment used depends on the stage of cancer.…”

Section: Introductionmentioning

confidence: 99%

Alantolactone inhibits cell autophagy and promotes apoptosis via AP2M1 in acute lymphoblastic leukemia

et al. 2020

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Background Acute lymphoblastic leukemia (ALL) is an aggressive hematopoietic malignancy that is most commonly observed in children. Alantolactone (ALT) has been reported to exhibit anti-tumor activity in different types of cancer. The aim of the present study was to investigate the anti-tumor activity and molecular mechanism of ALT in ALL. Methods ALL cell lines were treated with 1, 5 and 10 μM ALT, and cell viability was assessed using an MTT assay and RNA sequencing. Flow cytometry, JC-1 staining and immunofluorescence staining assays were used to measure cell apoptosis and autophagy. Additionally, western blot analysis was used to detect expression of apoptosis and autophagy related proteins. Finally, the effects of ALT on tumor growth were assessed in a BV173 xenograft nude mouse model. Results ALT inhibited the proliferation of ALL cells in a dose-dependent manner. Additionally, it was demonstrated that ALT inhibited cell proliferation, colony formation, autophagy, induced apoptosis and reduced tumor growth in vivo through upregulating the expression of adaptor related protein complex 2 subunit mu 1 (AP2M1). Moreover, the autophagy activator rapamycin, attenuated the pro-apoptotic effects of ALT on BV173 and NALM6 cell lines. Overexpression of AP2M1 decreased the expression of Beclin1 and the LC3-II/LC3-1 ratio, and increased p62 expression. Knockdown of Beclin1 increased the levels of bax, cleaved caspase 3 and cytochrome C, and decreased bcl-2 expression. Conclusions The present study demonstrated that ALT exerts anti-tumor activity through inducing apoptosis and inhibiting autophagy by upregulating AP2M1 in ALL, highlighting a potential therapeutic strategy for treatment of ALL.

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“…Genomic studies have provided conflicting evidence regarding the role of CRLF2/IL7RA aberrations in leukemic evolution. Aberrant expression of the receptors may be clonal or subclonal, preserved or altered between diagnosis and relapse 7,[19][20][21] . Two mouse models suggest that under specific conditions, expression of CRLF2 and/or IL7RA may initiate BCP-ALL [22][23][24] .…”

Section: Introductionmentioning

confidence: 99%

An instructive role for IL7RA in the development of human B-cell precursor leukemia

Geron

Savino

Tal

et al. 2020

Preprint

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B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is preceded by a clinically silent preleukemia. Experimental models that authentically re-capitulate disease initiation and progression in human cells are lacking. We previously described activating mutations in interleukin 7 receptor alpha (IL7RA) that are associated with the poor-prognosis Philadelphialike (Ph-like) subtype of BCP-ALL. Whether IL7RA signaling has a role in initiation of human BCP-ALL is unknown. IL7RA is essential for mouse B-cell development; however, patients with truncating IL7RA germline mutations develop normal mature B-cell populations. Herein, we explore the consequences of aberrant IL7RA signaling activation in human hematopoietic progenitors on malignant B-cell development. Transplantation of human cord-blood hematopoietic progenitors transduced with activated mutant IL7RA into NOD/LtSz-scid IL2Rγ null mice resulted in B-cell differentiation arrest with aberrant expression of CD34 + and persistence of pro-B cells that survive despite failing to achieve productive rearrangement of immunoglobulin V(D)J gene segments. Activation of IL7RA signaling enhanced self-renewal and facilitated the development of a BCP-ALL in secondary transplanted mice. The development of leukemia was associated with spontaneous acquired deletions in CDKN2A/B and IKZF1 similar to what is observed in Ph-like BCP-ALL in humans. Single cell gene expression analysis suggested that pre-leukemic cells resided within a subpopulation of early B-cell precursors with CD34 + CD10 high CD19 low immunophenotype. The development of a bona fide BCP-ALL from IL7RA transduced cells supports the hypothesis that aberrant activation of the IL7RA pathway in human B-cell lineage progenitors has an instructive role by creating a pre-leukemic state which is vulnerable to transformation. These are the first demonstrations of a role for IL7RA in human B-cell differentiation and of a de-novo Phlike BCP-ALL development from normal human hematopoietic progenitors in vivo.

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Single-cell analysis identifies CRLF2 rearrangements as both early and late events in Down syndrome and non-Down syndrome acute lymphoblastic leukaemia

Cited by 26 publications

References 57 publications

RAS activation via CRLF2 signaling is a widespread mechanism in Down syndrome acute lymphoblastic leukemia regardless of RAS mutations

RAS activation via CRLF2 signaling is a widespread mechanism in Down syndrome acute lymphoblastic leukemia regardless of RAS mutations

Alantolactone inhibits cell autophagy and promotes apoptosis via AP2M1 in acute lymphoblastic leukemia

An instructive role for IL7RA in the development of human B-cell precursor leukemia

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