High EVI1 expression is associated with MLL rearrangements and predicts decreased survival in paediatric acute myeloid leukaemia: a report from the children's oncology group

Ectopic viral integration site‐1 (EVI1) is highly expressed in certain cytogenetic subsets of adult acute myeloid leukaemia (AML), and has been associated with inferior survival. We sought to examine the clinical and biological associations of EVI1^high, defined as expression in excess of normal controls, in paediatric AML. EVI1 mRNA expression was measured via quantitative real‐time polymerase chain reaction in diagnostic specimens obtained from 206 patients. Expression levels were correlated with clinical features and outcome. EVI1^high was present in 58/206 (28%) patients. MLL rearrangements occurred in 40% of EVI1^high patients as opposed to 12% of the EVI1^low/absent patients (P < 0·001). No abnormalities of 3q26 were found in EVI1^high patients by conventional cytogenetic analysis, nor were cryptic 3q26 abnormalities detected in a subset of patients screened by next‐generation sequencing. French‐American‐British class M7 was enriched in the EVI1^high group, accounting for 24% of these patients. EVI1^high patients had significantly lower 5‐year overall survival from study entry (51% vs. 68%, P = 0·015). However, in multivariate analysis including other established prognostic markers, EVI1 expression did not retain independent prognostic significance. EVI1 expression is currently being studied in a larger cohort of patients enrolled on subsequent Children's Oncology Group trials, to determine if EVI1^high has prognostic value in MLL‐rearranged or intermediate‐risk subsets.     

The induction of immunogenic cell death by type II anti‐CD20 monoclonal antibodies has mechanistic differences compared with type I rituximab

The ASXL1 gene encodes a chromatin‐binding protein involved in epigenetic regulation in haematopoietic cells. Loss‐of‐function ASXL1 mutations occur in patients with a range of myeloid malignancies and are associated with adverse outcome. We have used lentiviral‐based shRNA technology to investigate the effects of ASXL1 silencing on cell proliferation, apoptosis, myeloid differentiation and global gene expression in human CD34⁺ cells differentiated along the myeloid lineage in vitro. ASXL1‐deficient cells showed a significant decrease in the generation of CD11b⁺ and CD15⁺ cells, implicating impaired granulomonocytic differentiation. Furthermore, colony‐forming assays showed a significant increase in the number of multipotent mixed lineage colony‐forming unit (CFU‐GEMM) colonies and a significant decrease in the numbers of granulocyte‐macrophage CFU (CFU‐GM) and granulocyte CFU (CFU‐G) colonies in ASXL1‐deficient cells. Our data suggests that ASXL1 knockdown perturbs human granulomonocytic differentiation. Gene expression profiling identified many deregulated genes in the ASXL1‐deficient cells differentiated along the granulomonocytic lineage, and pathway analysis showed that the most significantly deregulated pathway was the LXR/RXR activation pathway. ASXL1 may play a key role in recruiting the polycomb repressor complex 2 (PRC2) to specific loci, and we found over‐representation of PRC2 targets among the deregulated genes in ASXL1‐deficient cells. These findings shed light on the functional role of ASXL1 in human myeloid differentiation.     

HMGA2 as a potential molecular target in KMT2A‐AFF1‐positive infant acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia (ALL) in infants is an intractable cancer in childhood. Although recent intensive chemotherapy progress has considerably improved ALL treatment outcome, disease cure is often accompanied by undesirable long‐term side effects, and efficient, less toxic molecular targeting therapies have been anticipated. In infant ALL cells with KMT2A (MLL) fusion, the microRNA let‐7b (MIRLET7B) is significantly downregulated by DNA hypermethylation of its promoter region. We show here that the expression of HMGA2, one of the oncogenes repressed by MIRLET7B, is reversely upregulated in infant ALL leukaemic cells, particularly in KMT2A‐AFF1 (MLL‐AF4) positive ALL. In addition to the suppression of MIRLET7B, KMT2A fusion proteins positively regulate the expression of HMGA2. HMGA2 is one of the negative regulators of CDKN2A gene, which encodes the cyclin‐dependent kinase inhibitor p16^INK4A. The HMGA2 inhibitor netropsin, when combined with demethylating agent 5‐azacytidine, upregulated and sustained the expression of CDKN2A, which resulted in growth suppression of KMT2A‐AFF1‐expressing cell lines. This effect was more apparent compared to treatment with 5‐azacytidine alone. These results indicate that the MIRLET7B‐HMGA2‐CDKN2A axis plays an important role in cell proliferation of leukaemic cells and could be a possible molecular target for the therapy of infant ALL with KMT2A‐AFF1.     

CXCR4 WHIM‐like frameshift and nonsense mutations promote ibrutinib resistance but do not supplant MYD88L265P‐directed survival signalling in Waldenström macroglobulinaemia cells

CXCR4^WHIM frameshift and nonsense mutations follow MYD88^L265P as the most common somatic variants in Waldenström Macroglobulinaemia (WM), and impact clinical presentation and ibrutinib response. While the nonsense (CXCR4^S338X) mutation has been investigated, little is known about CXCR4 frameshift (CXCR4^FS) mutations. We engineered WM cells to express CXCR4^FS mutations present in patients, and compared their CXCL12 (SDF‐1a) induced signalling and ibrutinib sensitivity to CXCR4^{wild‐type (WT)} and CXCR4^S338X cells. Following CXCL12 stimulation, CXCR4^FS and CXCR4^S338X WM cells showed impaired CXCR4 receptor internalization, and enhanced AKT1 (also termed AKT) and MAPK1 (also termed ERK) activation versus CXCR^WT cells (P < 0·05), though MAPK1 activation was more prolonged in CXCR4^S338X cells (P < 0·05). CXCR4^FS and CXCR4^S338X cells, but not CXCR4^WT cells, were rescued from ibrutinib‐triggered apoptosis by CXCL12 that was reversed by AKT1, MAPK1 or CXCR4 antagonists. Treatment with an inhibitor that blocks MYD88^L265P signalling triggered similar levels of apoptosis that was not abrogated by CXCL12 treatment in CXCR4^WT and CXCR4^WHIM cells. These studies show a functional role for CXCR4^FS mutations in WM, and provide a framework for the investigation of CXCR4 antagonists with ibrutinib in CXCR4^WHIM‐mutated WM patients. Direct inhibition of MYD88^L265P signalling overcomes CXCL12 triggered survival effects in CXCR4^WHIM‐mutated cells supporting a primary role for this survival pathway in WM.     

Melatonin‐related genes expressed in the mouse uterus during early gestation promote embryo implantation

Melatonin, a superior antioxidant, is an important molecule which regulates female reproduction due to its receptor‐mediated and receptor‐independent antioxidant actions. In this study, we investigated the effect of melatonin on early gestation in a mouse model. During early gestation, the expression of the melatonin's rate‐limiting enzyme, AANAT, gradually increased – in the uterus while the MT2 melatonin receptor was only expressed at day 2 of gestation and no MT1 was detected. Based on these findings, we conducted a melatonin injection experiment which demonstrated that 15 mg/kg melatonin significantly improved the number of implantation sites and the litter size. Also, the blastocyst and uterus were collected to identify the local action of melatonin. In the melatonin‐treated mice, the endometrium was thicker than in the control mice; melatonin also caused an increase in density of uterine glands, and the uterine gland index (UGI) was significantly elevated over that of the control. Serum steroid hormone measurements revealed that at day 6 of gestation (postimplantation), melatonin significantly downregulated the E₂ level, with no obvious effects on progesterone. Gene expression assay revealed that melatonin significantly upregulated expression of HB‐EGF, a crucial gene involved in implantation as well as its receptor ErbB1 in the blastocyst. In addition, PRA, an important gene which influences the decidual response and luminal cell differentiation, p53, which regulates uterine through leukaemia inhibitory factor (LIF), were both increased after melatonin treatment. These data suggest that melatonin and its MT2 receptor influence early gestation. Exogenous melatonin treatment can improve mouse embryo implantation and litter size, which may have important applications in human reproductive health and animal husbandry.     

A 4‐gene expression score associated with high levels of Wilms Tumor‐1 (WT1) expression is an adverse prognostic factor in acute myeloid leukaemia

Wilms Tumor‐1 (WT1) expression level is implicated in the prognosis of acute myeloid leukaemia (AML). We hypothesized that a gene expression profile associated with WT1 expression levels might be a good surrogate marker. We identified high WT1 gene sets by comparing the gene expression profiles in the highest and lowest quartiles of WT1 expression in two large AML studies. Two high WT1 gene sets were found to be highly correlated in terms of the altered genes and expression profiles. We identified a 17‐probe set signature of the high WT1 set as the optimal prognostic predictor in the first AML set, and showed that it was able to predict prognosis in the second AML series after adjustment for European LeukaemiaNet genetic groups. The gene signature also proved to be of prognostic value in a third AML series of 163 samples assessed by RNA sequencing, demonstrating its cross‐platform consistency . This led us to derive a 4‐gene expression score, which faithfully predicted adverse outcome. In conclusion, a short gene signature associated with high WT1 expression levels and the resultant 4‐gene expression score were found to be predictive of adverse prognosis in AML. This study provides new clues to the molecular pathways underlying high WT1 states in leukaemia.     

Daily differential expression of melatonin‐related genes and clock genes in rat cumulus–oocyte complex: changes after pinealectomy

This study investigated the maturational stage (immature and mature ovaries) differences of mRNA expression of melatonin‐forming enzymes (Aanat and Asmt), melatonin membrane receptors (Mt1 and Mt2) and putative nuclear (Rorα) receptors, and clock genes (Clock, Bmal1, Per1, Per2, Cry1, Cry2) in cumulus–oocyte complexes (COC) from weaning Wistar rats. We also examined the effects of pinealectomy and of melatonin pharmacological replacement on the daily expression of these genes in COC. qRT‐PCR analysis revealed that in oocytes, the mRNA expression of Asmt, Mt2, Clock, Bmal1, Per2, and Cry1 were higher (P < 0.05) in immature ovaries than in the mature ones. In cumulus cells, the same pattern of mRNA expression for Asmt, Aanat, Rorα, Clock, Per1, Cry1, and Cry2 genes was observed. In oocytes, pinealectomy altered the daily mRNA expression profiles of Asmt, Mt1, Mt2, Clock, Per1, Cry1, and Cry2 genes. In cumulus cells, removal of the pineal altered the mRNA expression profiles of Mt1, Mt2, Rorα, Aanat, Asmt, Clock, Bmal1, Per2, Cry1, and Cry2 genes. Melatonin treatment partially or completely re‐established the daily mRNA expression profiles of most genes studied. The mRNA expression of melatonin‐related genes and clock genes in rat COC varies with the maturational stage of the meiotic cellular cycle in addition to the hour of the day. This suggests that melatonin might act differentially in accordance with the maturational stage of cumulus/oocyte complex. In addition, it seems that circulating pineal melatonin is very important in the design of the daily profile of mRNA expression of COC clock genes and genes related to melatonin synthesis and action.     

Clonal architecture of CXCR4 WHIM‐like mutations in Waldenström Macroglobulinaemia

CXCR4^WHIM somatic mutations are distinctive to Waldenström Macroglobulinaemia (WM), and impact disease presentation and treatment outcome. The clonal architecture of CXCR4^WHIM mutations remains to be delineated. We developed highly sensitive allele‐specific polymerase chain reaction (AS‐PCR) assays for detecting the most common CXCR4^WHIM mutations (CXCR4^{S338X C>A and C>G}) in WM. The AS‐PCR assays detected CXCR4^S338X mutations in WM and IgM monoclonal gammopathy of unknown significance (MGUS) patients not revealed by Sanger sequencing. By combined AS‐PCR and Sanger sequencing, CXCR4^WHIM mutations were identified in 44/102 (43%), 21/62 (34%), 2/12 (17%) and 1/20 (5%) untreated WM, previously treated WM, IgM MGUS and marginal zone lymphoma patients, respectively, but no chronic lymphocytic leukaemia, multiple myeloma, non‐IgM MGUS patients or healthy donors. Cancer cell fraction analysis in WM and IgM MGUS patients showed CXCR4^S338X mutations were primarily subclonal, with highly variable clonal distribution (median 35·1%, range 1·2–97·5%). Combined AS‐PCR and Sanger sequencing revealed multiple CXCR4^WHIM mutations in many individual WM patients, including homozygous and compound heterozygous mutations validated by deep RNA sequencing. The findings show that CXCR4^WHIM mutations are more common in WM than previously revealed, and are primarily subclonal, supporting their acquisition after MYD88^L265P in WM oncogenesis. The presence of multiple CXCR4^WHIM mutations within individual WM patients may be indicative of targeted CXCR4 genomic instability.     

Role of Functional IFNL4, IFNLR1, IFNA,IFNAR2 Polymorphisms in Hepatitis B virus‐related liver disease in Han Chinese population

Recent studies show that variants in some interferon genes together with interferon receptor genes are associated with the outcome of infectious diseases. We examined the association between the risk of hepatitis B virus (HBV)‐related liver disease and the functional polymorphisms within IFNL4, IFNLR1, IFNA1, IFNA2, IFNA5 and IFNAR2 genes (14 loci in all) in a Han Chinese population. A total of 3128 people participated and were divided into 5 groups: healthy controls, natural clearance, chronic hepatitis B(CHB), liver cirrhosis and hepatocellular carcinoma (HCC). Significant associations were observed for 4 variants in IFNAR2, IFNLR1 with HBV infection, and IFNLR1‐rs4649203 was associated with HBV recovery. Moreover, we demonstrated the clear relevance of 5 polymorphisms in IFNA1, IFNA2, IFNL4 with HCC. Three SNPs in IFNL4 gene may be important susceptible factors for the progression of HBV‐related liver disease by trend chi‐square test. The IFNL4 haplotype conformed by rs12971396_G, rs8113007_T and rs7248668A was more frequent in HCC than CHB and LC group. Three polymorphisms in the 5′ region of the IFNL4 gene are associated with the progression of HBV‐related liver disease. IFNA1‐ rs1831583 and IFNA2‐ rs649053 are associated with the development of HCC. IFNLR1‐ rs4649203, rs7525481 are predictors for HBV infection, and rs4649203 is a predictor of spontaneous clearance. IFNAR2 ‐rs1051393, rs12233338 may be predictive markers of HBV infection in the Chinese population.     

Hepatic compartmentalization of exhausted and regulatory cells in HIV/HCV‐coinfected patients

Accelerated intrahepatic hepatitis C virus (HCV) pathogenesis is likely the result of dysregulation within both the innate and adaptive immune compartments, but the exact contribution of peripheral blood and liver lymphocyte subsets remains unclear. Prolonged activation and expansion of immunoregulatory cells have been thought to play a role. We determined immune cell subset frequency in contemporaneous liver and peripheral blood samples from chronic HCV‐infected and HIV/HCV‐coinfected individuals. Peripheral blood mononuclear cells (PBMC) and biopsy‐derived liver‐infiltrating lymphocytes from 26 HIV/HCV‐coinfected, 10 chronic HCV‐infected and 10 HIV‐infected individuals were assessed for various subsets of T and B lymphocytes, dendritic cell, natural killer (NK) cell and NK T‐cell frequency by flow cytometry. CD8⁺ T cells expressing the exhaustion marker PD‐1 were increased in HCV‐infected individuals compared with uninfected individuals (P = 0.02), and HIV coinfection enhanced this effect (P = 0.005). In the liver, regulatory CD4⁺CD25⁺Foxp3⁺ T cells, as well as CD4⁺CD25⁺PD1⁺ T cells, were more frequent in HIV/HCV‐coinfected than in HCV‐monoinfected samples (P < 0.001). HCV was associated with increased regulatory T cells, PD‐1⁺ T cells and decreased memory B cells, regardless of HIV infection (P ≤ 0.005 for all). Low CD8⁺ expression was observed only in PD‐1⁺CD8⁺ T cells from HCV‐infected individuals and healthy controls (P = 0.002) and was associated with enhanced expansion of exhausted CD8⁺ T cells when exposed in vitro to PHA or CMV peptides. In conclusion, in HIV/HCV coinfection, ongoing HCV replication is associated with increased regulatory and exhausted T cells in the periphery and liver that may impact control of HCV. Simultaneous characterization of liver and peripheral blood highlights the disproportionate intrahepatic compartmentalization of immunoregulatory T cells, which may contribute to establishment of chronicity and hepatic fibrogenesis in HIV coinfection.     

High PRDM16 expression identifies a prognostic subgroup of pediatric acute myeloid leukaemia correlated to FLT3‐ITD,KMT2A‐PTD,and NUP98‐NSD1: the results of the Japanese Paediatric Leukaemia/Lymphoma Study Group AML‐05 trial

Recent reports described the NUP98‐NSD1 fusion as an adverse prognostic marker for acute myeloid leukaemia (AML) and PRDM16 (also known as MEL1) as the representative overexpressed gene in patients harbouring NUP98‐NSD1 fusion. PRDM16 gene expression levels were measured via real‐time polymerase chain reaction in 369 paediatric patients with de novo AML, of whom 84 (23%) exhibited PRDM16 overexpression (PRDM16/ABL1 ratio ≥ 0·010). The frequencies of patients with high or low PRDM16 expression differed widely with respect to each genetic alteration, as follows: t(8;21), 4% vs. 96%, P < 0·001; inv(16), 0% vs. 100%, P < 0·001; KMT2A (also termed MLL)‐ partial tandem duplication, 100% vs. 0%, P < 0·001; NUP98‐NSD1, 100% vs. 0%, P < 0·001. The overall survival (OS) and event‐free survival (EFS) among PRDM16‐overexpressing patients were significantly worse than in patients with low PRDM16 expression (3‐year OS: 51% vs. 81%, P < 0·001, 3‐year EFS: 32% vs. 64%, P < 0·001) irrespective of other cytogenetic alterations except for NPM1. PRDM16 gene expression was particularly useful for stratifying FLT3‐internal tandem duplication‐positive AML patients (3‐year OS: high = 30% vs. low = 70%, P < 0·001). PRDM16 overexpression was highly recurrent in de novo paediatric AML patients with high/intermediate‐risk cytogenetic profiles and was independently associated with an adverse outcome.     

Identification of emerging FLT3 ITD‐positive clones during clinical remission and kinetics of disease relapse in acute myeloid leukaemia with mutated nucleophosmin

FLT3 internal tandem duplication (ITD) mutations are frequently detected at diagnosis in cytogenetically normal acute myeloid leukaemia (CN‐AML) and predict unfavourable outcome. FLT3 ITD is an unstable aberration and may be lost or acquired at relapse. Recent whole genome sequencing studies have suggested that FLT3 ITD⁺ve AML relapse may evolve from small subclones undetectable at diagnosis by routine polymerase chain reaction (PCR). We developed a patient‐specific real‐time quantitative‐PCR (RQ‐PCR) to implement FLT3 ITD detection in six AML patients whose blasts carried wild‐type FLT3 at diagnosis and who relapsed with FLT3 ITD by routine PCR. Patient‐specific forward primers were designed after cloning and sequencing the FLT3 ITD in each case. The assay allowed retrospective detection of FLT3 ITD in diagnostic samples of 4/6 cases and to establish the kinetics of clonal evolution preceding relapse. After conventional chemotherapy, all patients had early relapse despite having been classified as NPM1⁺ve/FLT3 ITD^?ve at presentation, with shorter remissions being observed in four patients re‐classified as FLT3 ITD⁺ve by the new assay. Notably, FLT3 ITD clone became detectable by conventional PCR in three patients tested during remission after initial treatment. Our data underscore the need of identifying low FLT3 ITD levels, which are probably associated with relapse in otherwise good prognosis CN‐AML.     

Dysregulation of the MIRLET7/HMGA2 axis with methylation of the CDKN2A promoter in myeloproliferative neoplasms

Overexpression of high mobility group AT‐hook 2 (Hmga2), which is negatively regulated by MIRLET7 micro RNAs through 3′‐untranslated region (3′UTR), causes proliferative haematopoiesis mimicking myeloproliferative neoplasms (MPNs) and contributes to progression of myelofibrosis in mice. Thus, we investigated HMGA2 mRNA expression in 66 patients with MPNs including 23 polycythaemia vera (PV), 33 essential thrombocythaemia (ET) and 10 primary myelofibrosis (PMF). HMGA2 mRNA expression, especially variant 1 with 3′UTR that contains MIRLET7‐specific sites, rather than variant 2 lacking 3′UTR, is frequently deregulated due to decreased MIRLET7 expression in granulocytes from over 20% of PV and ET, and in either granulocytes or CD34⁺ cells from 100% of PMF. Patients with deregulated HMGA2 mRNA expression were significantly more likely to show splenomegaly, high serum lactate dehydrogenase values, and methylation of the CDKN2A promoter compared with other patients without deregulation of HMGA2. A histone deacetylase inhibitor, panobinostat, significantly increased MIRLET7 expression and reduced variant 1 of HMGA2 mRNA expression, but not variant 2, in both U937 cells and PMF‐derived CD34⁺ cells. Moreover, both panobinostat and small interfering RNA of HMGA2 demethylated the CDKN2A promoter in U937 cells. In conclusion, the frequently dysregulated MIRLET7/HMGA2 axis could be a therapeutic target in MPNs.     

Chronic liraglutide therapy induces an enhanced endogenous glucagon‐like peptide‐1 secretory response in early type 2 diabetes

Sustained exogenous stimulation of a hormone‐specific receptor can affect endogenous hormonal regulation. In this context, little is known about the impact of chronic treatment with glucagon‐like peptide‐1 (GLP‐1) agonists on the endogenous GLP‐1 response. We therefore evaluated the impact of chronic liraglutide therapy on endogenous GLP‐1 and glucose‐dependent insulinotropic polypeptide (GIP) response to an oral glucose challenge. A total of 51 people with type 2 diabetes of 2.6 ± 1.9 years’ duration were randomized to daily subcutaneous liraglutide or placebo injection and followed for 48 weeks, with an oral glucose tolerance test (OGTT) every 12 weeks. GLP‐1 and GIP responses were assessed according to their respective area under the curve (AUC) from measurements taken at 0, 30, 60, 90 and 120 minutes during each OGTT. There were no differences in AUC_GIP between the groups. By contrast, although fasting GLP‐1 was unaffected, the liraglutide arm had ~2‐fold higher AUC_{GLP ‐1} at 12 weeks ( P < .001), 24 weeks ( P < .001), 36 weeks ( P = .03) and 48 weeks ( P = .03), as compared with placebo. Thus, chronic liraglutide therapy induces a previously unrecognized, robust and durable enhancement of the endogenous GLP‐1 response, highlighting the need for further study of the long‐term effects of incretin mimetics on L‐cell physiology.