Group 2 innate lymphoid cells (ILC2s) are involved in human diseases, such as allergy, atopic dermatitis and nasal polyposis, but their function in human cancer remains unclear. Here we show that, in ...acute promyelocytic leukaemia (APL), ILC2s are increased and hyper-activated through the interaction of CRTH2 and NKp30 with elevated tumour-derived PGD2 and B7H6, respectively. ILC2s, in turn, activate monocytic myeloid-derived suppressor cells (M-MDSCs) via IL-13 secretion. Upon treating APL with all-trans retinoic acid and achieving complete remission, the levels of PGD2, NKp30, ILC2s, IL-13 and M-MDSCs are restored. Similarly, disruption of this tumour immunosuppressive axis by specifically blocking PGD2, IL-13 and NKp30 partially restores ILC2 and M-MDSC levels and results in increased survival. Thus, using APL as a model, we uncover a tolerogenic pathway that may represent a relevant immunosuppressive, therapeutic targetable, mechanism operating in various human tumour types, as supported by our observations in prostate cancer.Group 2 innate lymphoid cells (ILC2s) modulate inflammatory and allergic responses, but their function in cancer immunity is still unclear. Here the authors show that, in acute promyelocytic leukaemia, tumour-activated ILC2s secrete IL-13 to induce myeloid-derived suppressor cells and support tumour growth.
Leukemias are routinely sub-typed for risk/outcome prediction and therapy choice using acquired mutations and chromosomal rearrangements. Down syndrome acute lymphoblastic leukemia (DS-ALL) is ...characterized by 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. We prove in a cell model that elevated CRLF2 in combination with constitutionally active JAK2 is sufficient to activate wtRAS. On primary clinical DS-ALL samples, we show that wtRAS-activation is an obligatory consequence of mutated/hyperphosphorylated JAK2. We further prove that CRLF2-ligand TSLP boosts the direct binding of active PTPN11 to wtRAS, providing the molecular mechanism for the wtRAS activation. Pre-inhibition of RAS or PTPN11, but not of PI3K or JAK-signaling, prevented TSLP-induced RAS-GTP boost. Cytotoxicity assays on primary clinical DS-ALL samples demonstrated that, regardless of mutation status, high-risk leukemic cells could only be killed using RAS-inhibitor or PTPN11-inhibitor, but not PI3K/JAK-inhibitors, suggesting a unified treatment target for up to 80% of DS-ALL. Importantly, protein activities-based principal-component-analysis multivariate clusters analyzed for independent outcome prediction using Cox proportional-hazards model showed that protein-activity (but not mutation-status) was independently predictive of outcome, demanding a paradigm-shift in patient-stratification strategy for precision therapy in high-risk ALL.
MicroRNA-34b down-regulation in acute myeloid leukemia was previously shown to induce CREB overexpression, thereby causing leukemia proliferation in vitro and in vivo. The role of microRNA-34b and ...CREB in patients with myeloid malignancies has never been evaluated. We examined microRNA-34b expression and the methylation status of its promoter in cells from patients diagnosed with myeloid malignancies. We used gene expression profiling to identify signatures of myeloid transformation. We established that microRNA-34b has suppressor ability and that CREB has oncogenic potential in primary bone marrow cell cultures and in vivo. MicroRNA-34b was found to be up-regulated in pediatric patients with juvenile myelomonocytic leukemia (n=17) and myelodysplastic syndromes (n=28), but was down-regulated in acute myeloid leukemia patients at diagnosis (n=112). Our results showed that hypermethylation of the microRNA-34b promoter occurred in 66% of cases of acute myeloid leukemia explaining the low microRNA-34b levels and CREB overexpression, whereas preleukemic myelodysplastic syndromes and juvenile myelomonocytic leukemia were not associated with hypermethylation or CREB overexpression. In paired samples taken from the same patients when they had myelodysplastic syndrome and again during the subsequent acute myeloid leukemia, we confirmed microRNA-34b promoter hypermethylation at leukemia onset, with 103 CREB target genes differentially expressed between the two disease stages. This subset of CREB targets was confirmed to associate with high-risk myelodysplastic syndromes in a separate cohort of patients (n=20). Seventy-eight of these 103 CREB targets were also differentially expressed between healthy samples (n=11) and de novo acute myeloid leukemia (n=72). Further, low microRNA-34b and high CREB expression levels induced aberrant myelopoiesis through CREB-dependent pathways in vitro and in vivo. In conclusion, we suggest that microRNA-34b controls CREB expression and contributes to myeloid transformation from both healthy bone marrow and myelodysplastic syndromes. We identified a subset of CREB target genes that represents a novel transcriptional network that may control myeloid transformation.
BCL2‐associated athanogene‐1 (BAG1) is a multi‐functional protein that is found deregulated in several solid cancers and in paediatric acute myeloid leukaemia. The investigation of BAG1 isoforms ...expression and intracellular localization in B‐cell acute lymphoblastic leukaemia (B‐ALL) patient‐derived specimens revealed that BAG1 levels decrease during disease remission, compared to diagnosis, but drastically increase at relapse. In particular, at diagnosis both BAG1‐L and BAG1‐M isoforms are mainly nuclear, while during remission the localization pattern changes, having BAG1‐M almost exclusively in the cytosol indicating its potential cytoprotective role in B‐ALL. In addition, knockdown of BAG1/BAG3 induces cell apoptosis and G1‐phase cell cycle arrest and, more intriguingly, shapes cell response to chemotherapy. BAG1‐depleted cells show an increased sensitivity to the common chemotherapeutic agents, dexamethasone or daunorubicin, and to the BCL2 inhibitor ABT‐737. Moreover, the BAG1 inhibitor Thio‐2 induces a cytotoxic effect on RS4;11 cells both in vitro and in a zebrafish xenograft model and strongly synergizes with pan‐BCL inhibitors. Collectively, these data sustain BAG1 deregulation as a critical event in assuring survival advantage to B‐ALL cells.
Summary
Relapse remains the leading cause of treatment failure in children with acute lymphoblastic leukaemia (ALL) undergoing allogeneic haematopoietic stem cell transplantation (HSCT). We ...retrospectively investigated the prognostic role of minimal residual disease (MRD) before and after HSCT in 119 children transplanted in complete remission (CR). MRD was measured by polymerase chain reaction in bone marrow samples collected pre‐HSCT and during the first and third trimesters after HSCT (post‐HSCT1 and post‐HSCT3). The overall event‐free survival (EFS) was 50%. The cumulative incidence of relapse and non‐relapse mortality was 41% and 9%. Any degree of detectable pre‐HSCT MRD was associated with poor outcome: EFS was 39% and 18% in patients with MRD positivity <1 × 10−3 and ≥1 × 10−3, respectively, versus 73% in MRD‐negative patients (P < 0·001). This effect was maintained in different disease remissions, but low‐level MRD had a very strong negative impact only in patients transplanted in second or further CR. Also, MRD after HSCT enabled patients to be stratified, with increasing MRD between post‐HSCT1 and post‐HSCT3 clearly defining cohorts with a different outcome. MRD is an important prognostic factor both before and after transplantation. Given that MRD persistence after HSCT is associated with dismal outcome, these patients could benefit from early discontinuation of immunosuppression, or pre‐emptive immuno‐therapy.
Some neonates with Down syndrome (DS) are diagnosed with self-regressing transient myeloproliferative disorder (TMD), and 20% to 30% of those progress to acute megakaryoblastic leukemia (AMKL). We ...performed exome sequencing in 7 TMD/AMKL cases and copy-number analysis in these and 10 additional cases. All TMD/AMKL samples contained GATA1 mutations. No exome-sequenced TMD/AMKL sample had other recurrently mutated genes. However, 2 of 5 TMD cases, and all AMKL cases, showed mutations/deletions other than GATA1, in genes proven as transformation drivers in non-DS leukemia (EZH2, APC, FLT3, JAK1, PARK2-PACRG, EXT1, DLEC1, and SMC3). One patient at the TMD stage revealed 2 clonal expansions with different GATA1 mutations, of which 1 clone had an additional driver mutation. Interestingly, it was the other clone that gave rise to AMKL after accumulating mutations in 7 other genes. Data suggest that GATA1 mutations alone are sufficient for clonal expansions, and additional driver mutations at the TMD stage do not necessarily predict AMKL progression. Later in infancy, leukemic progression requires “third-hit driver” mutations/somatic copy-number alterations found in non-DS leukemias. Putative driver mutations affecting WNT (wingless-related integration site), JAK-STAT (Janus kinase/signal transducer and activator of transcription), or MAPK/PI3K (mitogen-activated kinase/phosphatidylinositol-3 kinase) pathways were found in all cases, aberrant activation of which converges on overexpression of MYC.
•DS TMD shows no DNA rearrangements and a low rate of mutations other than GATA1.•DS AMKL always has rearrangements and mutations in genes known for leukemic progression; affected pathways share upregulation of MYC.
Children with Down syndrome (DS) and acute lymphoblastic leukaemia (ALL) have poorer survival and more relapses than non-DS children with ALL, highlighting an urgent need for deeper mechanistic ...understanding of DS-ALL. Here, using full-exome or cancer genes-targeted sequencing of 42 ALL samples from 39 DS patients, we uncover driver mutations in RAS, (KRAS and NRAS) recurring to a similar extent (15/42) as JAK2 (12/42) mutations or P2RY8-CRLF2 fusions (14/42). RAS mutations are almost completely mutually exclusive with JAK2 mutations (P=0.016), driving a combined total of two-thirds of analysed cases. Clonal architecture analysis reveals that both RAS and JAK2 drove sub-clonal expansions primarily initiated by CRLF2 rearrangements, and/or mutations in chromatin remodellers and lymphocyte differentiation factors. Remarkably, in 2/3 relapsed cases, there is a switch from a primary JAK2- or PTPN11-mutated sub-clone to a RAS-mutated sub-clone in relapse. These results provide important new insights informing the patient stratification strategies for targeted therapeutic approaches for DS-ALL.
To induce and sustain the leukaemogenic process, MLL-AF4+ leukaemia seems to require very few genetic alterations in addition to the fusion gene itself. Studies of infant and paediatric patients with ...MLL-AF4+ B cell precursor acute lymphoblastic leukaemia (BCP-ALL) have reported mutations in KRAS and NRAS with incidences ranging from 25 to 50%. Whereas previous studies employed Sanger sequencing, here we used next generation amplicon deep sequencing for in depth evaluation of RAS mutations in 36 paediatric patients at diagnosis of MLL-AF4+ leukaemia. RAS mutations including those in small sub-clones were detected in 63.9% of patients. Furthermore, the mutational analysis of 17 paired samples at diagnosis and relapse revealed complex RAS clone dynamics and showed that the mutated clones present at relapse were almost all originated from clones that were already detectable at diagnosis and survived to the initial therapy. Finally, we showed that mutated patients were indeed characterized by a RAS related signature at both transcriptional and protein levels and that the targeting of the RAS pathway could be of beneficial for treatment of MLL-AF4+ BCP-ALL clones carrying somatic RAS mutations.
Acute lymphoblastic leukemia (ALL) in infants is a relatively rare disease with peculiar biological features, high frequency of KMT2A gene rearrangements and grim prognosis. Even with new therapeutic ...approaches, event-free survival (EFS) in infants with ALL does not exceed 50%. Currently large cooperative studies of infant ALL have been promoted by the Interfant and MLL-Baby networks. Minimal residual disease (MRD) monitoring is considered a strong tool for optimizing management of childhood ALL. In contrast to older children in this age group the prognostic impact of MRD detected by multicolor flow cytometry (MFC) is still unclear. Aim of the present study was to evaluate the prognostic value of MFC MRD measurement during induction in infants with ALL treated with Interfant-99 and Interfant-06 protocols in AIEOP centers in Italy as well as MLL-Baby protocol in Russia and Belarus.
Patients and methods. Two independent groups of patients were investigated: study cohort of 139 consecutive infants with newly diagnosed ALL enrolled between September 2003 and April 2016 in Russian and Belorussian centers with MLL-Baby protocol and validation group of 146 ones enrolled in AIEOP centers in Interfant trials during the same period. By availability of MFC MRD data obtained at day 15 and/or end of induction (EOI), 81 and 86 patients of study and validation cohorts respectively were selected for outcome evaluation. In 61 MLL-Baby patients (75.3%) and 61 AIEOP cases (70.9%) different types of KMT2A gene rearrangements were identified. All patients were diagnosed as BCP-ALL, except one with cortical T-ALL. Overall, day 15 samples were studied in 64 MLL-Baby patients and 73 AIEOP cases while EOI samples in 75 and 63 cases respectively. MRD detection was performed in Reference Laboratories in Ekaterinburg, Minsk and Padua according the BFM AIEOP FLOW Network SOP. MRD negativity was defined as <0.01% of all bone marrow nucleated cells.
Results. Patients were stratified according to the AIEOP-BFM-ALL day 15 stratification usually used for older children into three risk groups: standard risk (SR: MRD<0.1%), intermediate risk (IR: MRD 0.1% to 10%) and high risk (HR: MRD≥10%). Patients' distribution was similar in both study and validation cohorts: 34.4% and 32.9% in SR, 53.1% and 54.5% in ImR, 12.5% and 12.3% in HR respectively. At EOI significant differences in MRD-positive and MRD-negative patients' distribution was observed in different protocols: 44 (58.7%) and 31 (41.3%) cases respectively for MLL-Baby, but 17 (27.0%) and 46 (73.0%) cases respectively for AIEOP group. It was observed that KMT2A-rearranged cases in both trials have slower MRD response compared to the children with wild type KMT2A. In study cohort the 22 SR patients had a 5-year EFS and cumulative incidence of relapse (CIR) significantly better than other ones, thus we considered two major groups of patients with different outcome: SR with 5-year EFS 67.4%, standard error (SE) 10.2; CIR 23.3%, SE 9.4 and non-SR with 5-year EFS 30.8%, SE 7.2; CIR 52.6%, SE 7.9, (p=0.0039 and p=0.0229, respectively). Difference between these groups was observed also in KMT2A-rearranged cases (n=49) both for 5-year EFS (60.0%, SE 12.7 and 23.2%, SE 7.3, p=0.0160) and in 5-year CIR (33.3%, SE 12.7 and 59.2%, SE 8.8, p=0.0881). Analysis of outcome in validation cohort confirmed these data. In study cohort outcome of children being MRD-negative at EOI (n=31, 5-year EFS 60.8%, SE 8.8 and CIR 29.3%, SE 8.4) was significantly better than that of MRD-positive patients (n=44, 5-year EFS 31.1%, SE 7.1 and CIR 57.6%, SE 7.8 with p=0.0153 and p=0.0267, respectively). Outcome by EOI MFC MRD in the validation cohort is generally in keeping with that of the study cohort. Interestingly, in AIEOP cohort MFC data showed a prognostic impact also in KMT2A-rearranged subgroup. In multivariate analysis with KMT2A-status, each MRD time-point data showed independent impact on the risk of relapse.
Conclusion. Our data was obtained by well-harmonized MFC MRD monitoring in a large group of infants with ALL treated in a multicenter setting with two different protocols. In spite of differences in therapy, we observed strong and independent prognostic impact of MFC MRD both at day 15 and at EOI regardless the protocol applied. We can conclude that MFC MRD can be used in combination with KMT2A-status to improve treatment allocation in future protocols.
Parasole:Servier: Honoraria; Baxalta: Honoraria; Eusapharma: Honoraria. Pieters:jazz farmaceuticals: Consultancy; medac: Consultancy.
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