Imprinted genes in myeloid lineage commitment in normal and malignant hematopoiesis

Acute Myeloid Leukemia Causes T Cell Exhaustion and Depletion in a Humanized Graft-versus-Leukemia Model

Allogeneic hematopoietic stem cell transplantation (alloSCT) is, in many clinical settings, the only curative treatment for acute myeloid leukemia (AML). The clinical benefit of alloSCT greatly relies on the graft-versus-leukemia (GVL) effect. However, AML relapse remains the top cause of posttransplant death; this highlights the urgent need to enhance GVL. Studies of human GVL have been hindered by the lack of optimal clinically relevant models. In this article, we report, the successful establishment of a novel (to our knowledge) humanized GVL model system by transplanting clinically paired donor PBMCs and patient AML into MHC class I/II knockout NSG mice. We observed significantly reduced leukemia growth in humanized mice compared with mice that received AML alone, demonstrating a functional GVL effect. Using this model system, we studied human GVL responses against human AML cells in vivo and discovered that AML induced T cell depletion, likely because of increased T cell apoptosis. In addition, AML caused T cell exhaustion manifested by upregulation of inhibitory receptors, increased expression of exhaustion-related transcription factors, and decreased T cell function. Importantly, combined blockade of human T cell-inhibitory pathways effectively reduced leukemia burden and reinvigorated CD8 T cell function in this model system. These data, generated in a highly clinically relevant humanized GVL model, not only demonstrate AML-induced inhibition of alloreactive T cells but also identify promising therapeutic strategies targeting T cell depletion and exhaustion for overcoming GVL failure and treating AML relapse after alloSCT.

Assisted Reproductive Technology and Risk of Childhood Cancers

IMPORTANCE

The number of children born through the use of assisted reproductive technology (ART) has been increasing. These children may have higher risks for epigenetic alteration and adverse perinatal outcomes, which may be associated with childhood cancers.

OBJECTIVE

To determine the associations between different modes of conception and childhood cancers and potential mediation by preterm birth and low birth weight.

DESIGN, SETTING, AND PARTICIPANTS

This nationwide, population-based cohort study included registry data from 2 308 016 eligible parents-child triads in Taiwan from January 1, 2004, to December 31, 2017. A total of 1880 children with incident childhood cancer were identified. Data were analyzed between September 1, 2020, and June 30, 2022.

EXPOSURE

Mode of conception, defined as (1) natural conception, (2) subfertility and non-ART (ie, infertility diagnosis but no ART-facilitated conception), or (3) ART (ie, infertility diagnosis and ART-facilitated conception).

MAIN OUTCOMES AND MEASURES

Diagnosis of childhood cancer according to the International Classification of Childhood Cancers, Third Edition.

RESULTS

The mean (SD) paternal and maternal ages were 33.28 (5.07) and 30.83 (4.56) years, respectively. Of the 2 308 016 children, 52.06% were boys, 8.16% were born preterm, and 7.38% had low birth weight. During 14.9 million person-years of follow-up (median, 6 years [IQR, 3-10 years]), ART conception was associated with an increased risk of any type of childhood cancers compared with natural conception (hazard ratio, 1.58; 95% CI, 1.17-2.12) and subfertility with non-ART conception (hazard ratio, 1.42; 95% CI, 1.04-1.95). The increased cancer risk of children conceived with ART was mainly owing to leukemia and hepatic tumor. The increased cancer risk associated with ART conception was not mediated by preterm birth or low birth weight.

CONCLUSIONS AND RELEVANCE

In this cohort study, children conceived via ART had a higher risk of childhood cancers than those conceived naturally and those born to parents with an infertility diagnosis did not use ART. The increased risk could not be explained by preterm birth or low birth weight.

Case Report: Refractory Cytopenia With a Switch From a Transient Monosomy 7 to a Disease-Ameliorating del(20q) in a NHEJ1-Deficient Long-term Survivor

We report the case of a male Pakistani patient with a pathogenic homozygous loss of function variant in the non-homologous end-joining factor 1 (NHEJ1) gene. The growth retarded and microcephalic boy with clinodactyly of both hands and hyperpigmentation of the skin suffered from recurrent respiratory infections. He was five and a half years old when he came to our attention with refractory cytopenia and monosomy 7. Hematopoietic stem cell transplantation was considered but not feasible because there was no suitable donor available. Monosomy 7 was not detected anymore in subsequent bone marrow biopsies that were repeated in yearly intervals. Instead, seven and a half years later, a novel clone with a del(20q) appeared and steadily increased thereafter. In parallel, the patient’s blood count, which had remained stable for over 20 years without necessitating any specific therapeutic interventions, improved gradually and the erythropoiesis-associated dysplasia resolved.

Increased methylation upstream of the MEG3 promotor is observed in acute myeloid leukemia patients with better overall survival

Background

The delta-like non-canonical Notch ligand 1 (DLK1)-maternally expressed 3(MEG3) locus (DLK1-MEG3 locus) plays a critical role in the maintenance and differentiation of hematopoietic stem cells. Accumulating evidence implicates the imprinted genes from this locus, DLK1 and MEG3, in the development and progression of acute myeloid leukemia (AML). However, the contribution of this locus to the treatment response of patients and their survival is unknown.

Methods

DNA methylation of select CG dinucleotide-containing amplicons (CpG sites) within the DLK1-MEG3 locus and within differentially methylated regions of other imprinted loci was assessed in the mononuclear cells of 45 AML patients by combined bisulfite restriction analysis. Methylation results were compared with patient response to first-round induction therapy and overall survival. Multivariable analysis was employed to identify independent prognostic factors for patient overall survival in AML.

Results

Increased methylation at CpG sites within the MEG3 promotor region was observed in AML patients having longer overall survival. In addition, patients with shorter overall survival had increased expression of DLK1 and MEG3, and methylation at the MEG3-DMR CpG site inversely correlated with MEG3 expression. Multivariable analysis revealed that methylation at CG9, a non-imprinted CpG site within the MEG3 promotor region which contains a CCCTC-binding factor (CTCF)-binding DNA sequence, is an independent prognostic factor for the overall survival of AML patients.

Conclusions

The results of our pilot study underscore the importance of the DLK1-MEG3 locus in AML development and progression. We identify CG9 methylation as an independent prognostic factor for AML patient survival, which suggests that distinct miRNA signatures from the DLK1-MEG3 locus could reflect varying degrees of cell stemness and present novel opportunities for personalized therapies in the future. These data provide a foundation for future studies into the role of higher-order chromatin structure at DLK1-MEG3 in AML.

Electronic supplementary material

The online version of this article (10.1186/s13148-019-0643-z) contains supplementary material, which is available to authorized users.

Novel evidence that pituitary gonadotropins directly stimulate human leukemic cells-studies of myeloid cell lines and primary patient AML and CML cells

We recently reported that normal hematopoietic stem cells express functional pituitary sex hormone (SexH) receptors. Here we report for the first time that pituitary-secreted gonadotrophins stimulate migration, adhesion, and proliferation of several human myeloid and lymphoid leukemia cell lines. Similar effects were observed after stimulation of human leukemic cell lines by gonadal SexHs. This effect seems to be direct, as the SexH receptors expressed by leukemic cells responded to stimulation by phosphorylation of MAPK_p42/44 and AKT_ser473. Furthermore, in parallel studies we confirmed that human primary patient-derived AML and CML blasts also express several functional SexH receptors. These results shed more light on the potential role of SexHs in leukemogenesis and, in addition, provide further evidence suggesting a developmental link between hematopoiesis and the germline.