MYB-GATA1 fusion promotes basophilic leukaemia: involvement of interleukin-33 and nerve growth factor receptors

Integrated enhancer regulatory network by enhancer-promoter looping in gastric cancer

Enhancer cis-regulatory elements play critical roles in gene regulation at many stages of cell growth. Enhancers in cancer cells also regulate the transcription of oncogenes. In this study, we performed a comprehensive analysis of long-range chromatin interactions, histone modifications, chromatin accessibility and expression in two gastric cancer (GC) cell lines compared to normal gastric epithelial cells. We found that GC-specific enhancers marked by histone modifications can activate a population of genes, including some oncogenes, by interacting with their proximal promoters. In addition, motif analysis of enhancer-promoter interacting enhancers showed that GC-specific transcription factors are enriched. Among them, we found that MYB is crucial for GC cell growth and activated by the enhancer with an enhancer-promoter loop and TCF7 upregulation. Clinical GC samples showed epigenetic activation of enhancers at the MYB locus and significant upregulation of TCF7 and MYB, regardless of molecular GC subtype and clinicopathological factors. Single-cell RNA sequencing of gastric mucosa with intestinal metaplasia showed high expression of TCF7 and MYB in intestinal stem cells. When we inactivated the loop-forming enhancer at the MYB locus using CRISPR interference (dCas9-KRAB), GC cell growth was significantly inhibited. In conclusion, we identified MYB as an oncogene activated by a loop-forming enhancer and contributing to GC cell growth.

Acute Basophilic Leukemia: Recent Molecular and Diagnostic Update

Acute basophilic leukemia (ABL) is an uncommon subtype of acute leukemia characterized by clinical signs and symptoms related to hyper-histaminemia. Patients usually present with bone marrow (BM) failure due to the infiltration of BM by the blasts and may or may not have circulating blasts. Myeloid markers such as CD13 and CD33 are expressed by leukemic blasts, which are also positive for CD123, CD203c, and CD11b, but KIT (CD117) and other monocytic markers are usually negative. t(X;6) (p11; q23) translocation resulting in the MYB-GATA1 fusion gene has been seen in sporadic cases of ABL. Early phases of hematopoiesis are characterized by high levels of MYB and low levels of GATA1; as differentiation develops, an inverse regulation occurs, resulting in high levels of GATA1 and low levels of MYB.The translocation t(X;6) produces the MYB-GATA1 fusion gene (p11; q23). In mouse lineage-negative cells, MYB-GATA1 expression commits them to the granulocyte lineage and inhibited differentiation at an early stage. Cells expressing MYB-GATA1 show enhanced expression of markers of immaturity (CD34), granulocytic lineage (CD33 and CD117), and basophilic differentiation (CD203c and FcRI). NTRK1 and IL1RL1 transcription is directly triggered by MYB and MYB-GATA1, resulting in basophilic skewing of the blasts.

Acute myeloid leukemia with t(X;6)9p11;q23);MYB-GATA1 and female sex: GATA1 insufficiency may be insufficient for pathogenesis

Pediatric acute myeloid leukemia (AML) is genetically heterogenous (Olsson et al., 2016). t(X;6)(p11;q23) is a rare but recurrent chromosomal translocation in infant AML thought to be associated with male sex and basophilic differentiation (Dastugue et al., 1997). Here we report molecular characterization of AML with t(X;6)(p11;q23);MYB-GATA1 in two female infants and demonstrate preserved GATA1 expression in the sample tested. These findings further debunk a concept that this fusion was restricted to males, in whom it disrupts the only copy of the X-linked GATA1 gene, causing presumable complete loss of GATA1 function. Our data also demonstrate the power and efficiency of RNA sequencing for subclassification of leukemia on a clinically relevant timeline.

Next-generation sequencing in two cases of de novo acute basophilic leukaemia

Acute basophilic leukaemia (ABL) is a rare subtype of acute myeloid leukaemia (AML); therefore, few data are available about its biology. Herein, we analysed two ABL patients using flow cytometry and next‐generation sequencing (NGS). Two cell populations were detected by flow cytometry in both patients. In Case no. 1, blasts (CD34⁺, CD203c⁻, CD117⁺, CD123dim⁺) and basophils (CD34⁻, CD203c⁺, CD117^±, CD123⁺) were identified, both of which were found by NGS to harbour the 17p deletion and have loss of heterozygosity of TP53. In Case no. 2, blasts (CD33⁺, CD34⁺, CD123⁻) and basophils (CD33⁺, CD34⁺, CD123⁺) were identified. NGS detected NPM1 mutations in either blasts or basophils, and TET2 in both. These data suggest an overlap of the mutational landscape of ABL and AML, including TP53 and TET2 mutations. Moreover, additional mutations or epigenetic factors may contribute for the differentiation into basophilic blasts.

MYB oncoproteins: emerging players and potential therapeutic targets in human cancer

MYB transcription factors are highly conserved from plants to vertebrates, indicating that their functions embrace fundamental mechanisms in the biology of cells and organisms. In humans, the MYB gene family is composed of three members: MYB, MYBL1 and MYBL2, encoding the transcription factors MYB, MYBL1, and MYBL2 (also known as c-MYB, A-MYB, and B-MYB), respectively. A truncated version of MYB, the prototype member of the MYB family, was originally identified as the product of the retroviral oncogene v-myb, which causes leukaemia in birds. This led to the hypothesis that aberrant activation of vertebrate MYB could also cause cancer. Despite more than three decades have elapsed since the isolation of v-myb, only recently investigators were able to detect MYB genes rearrangements and mutations, smoking gun evidence of the involvement of MYB family members in human cancer. In this review, we will highlight studies linking the activity of MYB family members to human malignancies and experimental therapeutic interventions tailored for MYB-expressing cancers.

Overexpression of Chimeric RNA by Retroviral Transduction

Cloning the open reading frame (ORF) of a protein-coding chimeric RNA into a mammalian expression vector is a simple, practiced way to study the function of the chimeric RNA. Here, we provide procedures for the insertion of the RRM2-C2orf48 fusion ORF into a mammalian expression vector, achieving the overexpression of the RRM2-C2orf48 fusion protein in a colon cancer cell line by retroviral transduction.

The ST2/Interleukin-33 Axis in Hematologic Malignancies: The IL-33 Paradox

Interleukin (IL)-33 is a chromatin-related nuclear interleukin that is a component of IL-1 family. IL-33 production augments the course of inflammation after cell damage or death. It is discharged into the extracellular space. IL-33 is regarded as an “alarmin” able to stimulate several effectors of the immune system, regulating numerous immune responses comprising cancer immune reactions. IL-33 has been demonstrated to influence tumorigenesis. However, as far as this cytokine is concerned, we are faced with what has sometimes been defined as the IL-33 paradox. Several studies have demonstrated a relevant role of IL-33 to numerous malignancies, where it may have pro- and—less frequently—antitumorigenic actions. In the field of hematological malignancies, the role of IL-33 seems even more complex. Although we can affirm the existence of a negative role of IL-33 in Chronic myelogenos leukemia (CML) and in lymphoproliferative diseases and a positive role in pathologies such as Acute myeloid leukemia (AML), the action of IL-33 seems to be multiple and sometimes contradictory within the same pathology. In the future, we will have to learn to govern the negative aspects of activating the IL-33/ST2 axis and exploit the positive ones.

Interleukin-33 in Malignancies: Friends or Foes?

The human Interleukin-33 (IL-33), a member of the IL-1 family, is the cytokine as a cell endogenous alarmin, released by damaged or necrotic barrier cells (endothelial and epithelial cells). The signal transduction of IL-33 relies on recognition and interaction with specific receptor ST2, mainly expressed in immune cells. In both innate and adoptive immunity, IL-33 regulates the homeostasis in response to stress from within/out the microenvironment. Various, even negative biofunctions of IL-33 pathways have now been widely verified in pathogenesis among immunological mechanisms, like Th2-related immune-stimuli, inflammation/infection-induced tissue protectors. A larger versatility in studies of IL-33 on malignancies now focuses on: (1) promoting myeloid-derived suppressor cells (MDSC), (2) intervention toward CD8⁺ T, Natural Killer (NK) cell infiltration, group 2 innate lymphoid cells (ILC2) proliferation, dendritic cells (DC) activation, and (3) inhibiting tumor growth and/or further metastasis as an immunoadjuvant. Although IL-33 functioned pro-tumorigenically in various cancers, for some cancer types the findings so far are controversial. This review begins from a summarized introduction of IL-33, to its remarkable implications and molecular transduction pathway in malignant neoplasms, ends with latest inspiration for IL-33 in treatment.

Acute basophilic leukemia associated with the t(16;21)(p11;q22)/FUS-ERG fusion gene

We herein report a rare case of acute basophilic leukemia with t(16;21)(p11;q22) generating the FUS‐ERG fusion gene. The basophilic nature of leukemia blasts was demonstrated by cytomorphology, toluidine blue metachromasia, mature basophil‐associated antigen expression, and characteristic granules under electron microscopy. The molecular link between t(16;21)/FUS‐ERG and basophilic differentiation remains unclear.

Predictors of early-onset post-ischemic stroke depression: a cross-sectional study

BACKGROUND

Post-stroke depression (PSD) seriously affects the rehabilitation of nerve function and quality of life. However, the pathogenesis of PSD is still not clear. This study aimed to investigate the demographic, clinical, and biochemical factors in patients with PSD.

METHODS

Patients with an acute ischemic stroke, who met the inclusion criteria at Shanghai Tenth People's Hospital from April 2016 to September 2016, were recruited for this study. The stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS), and the mental state was assessed using Mini-Mental State Examination (MMSE), Hamilton Depression Scale (HAMD), and Hamilton Anxiety Scale (HAMA) at 1 week of admission. The patients were divided into PSD and non-PSD groups. The demographic and clinical characteristics, as well as the biochemical factors, were compared between the two groups. A logistic regression analysis was performed to identify the risk factors for depression following stroke.

RESULTS

A total of 83 patients with acute ischemic stroke were recruited. Of these, 36 (43.4%) developed depression. The multivariate logistic regression analysis indicated that high NIHSS [odds ratio (OR): 1.84, 95% confidence interval (CI): 1.09-3.12, P = 0.023] and high HAMD scores (OR: 2.38, 95% CI: 1.61-3.50, P < 0.001) were independent risk predictors for PSD and so were lower dopamine level (OR: 0.64, 95% CI: 0.45-0.91, P = 0.014), lower 5-hydroxytryptamine level (OR: 0.99, 95% CI: 0.98-1.00, P = 0.046), higher tumor necrosis factor-α level (OR: 1.05, 95% CI: 1.00-1.09, P = 0.044), and lower nerve growth factor level (OR: 0.06, 95% CI: 0.01-0.67, P = 0.022).

CONCLUSIONS

The identification of higher NIHSS scores, higher HAMD scores, lower dopamine level, lower 5-hydroxytryptamine level, higher tumor necrosis factor-α level, and lower nerve growth factor level might be useful for clinicians in recognizing and treating depression in patients after a stroke.