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Background: ZNF384‐fusion (Z‐fusion) genes were recently identified in B‐cell acute lymphoblastic leukemia (B‐ALL) and are frequent in Japanese adult patients. The frequency is about 20% in those with Philadelphia chromosome‐negative B‐ALL. ZNF384 is a transcription factor and Z‐fusion proteins have increased transcriptional activity; however, the detailed mechanisms of leukemogenesis of Z‐fusion proteins have yet to be clarified. Methods: We established three transfectants of cell lines expressing different types of Z‐fusion proteins, and analyzed their gene expression profile (GEP) by RNA‐seq. We also analyzed the GEP of clinical ALL samples using our previous RNA‐seq data of 323 Japanese ALL patients. We selected upregulated genes in both Z‐fusion gene‐expressing transfectants and Z‐fusion gene‐positive ALL samples, and investigated the binding of Z‐fusion proteins to regulatory regions of the candidate genes by ChIP‐qPCR. Results: We selected six commonly upregulated genes. After the investigation by ChIP‐qPCR, we finally identified CREB5 and RGS1 as direct and common target genes. RGS1 is an inhibitor of CXCL12‐CXCR4 signaling that is required for the homing of hematopoietic progenitor cells to the bone marrow microenvironment and development of B cells. Consistent with this, Z‐fusion gene transfectants showed impaired migration toward CXCL12. Conclusions: We identified CREB5 and RGS1 as direct and common transcriptional targets of Z‐fusion proteins. The present results provide novel insight into the aberrant transcriptional regulation by Z‐fusion proteins. [ABSTRACT FROM AUTHOR]

Introduction: Nucleoporin 98 (NUP98) fusion proteins are recurrently found in leukemia and are associated with unfavorable clinical outcomes. They are distributed to the nucleus and contribute to leukemogenesis via aberrant transcriptional regulation. We previously identified NUP98‐BPTF (NB) fusion in patients with T‐cell acute lymphoblastic leukemia (T‐ALL) using next‐generation sequencing. The FG‐repeat of NUP98 and the PHD finger and bromodomain of bromodomain PHD finger transcription factor (BPTF) are retained in the fusion. Like other NUP98 fusion proteins, NB is considered to regulate genes that are essential for leukemogenesis. However, its target genes or pathways remain unknown. Materials and Methods: To investigate the potential oncogenic properties of the NB fusion protein, we lentivirally transduced a doxycycline‐inducible NB expression vector into mouse NIH3T3 fibroblasts and human Jurkat T‐ALL cells. Results: NB promoted the transformation of mouse NIH3T3 fibroblasts by upregulating the proto‐oncogene Pim1, which encodes a serine/threonine kinase. NB transcriptionally regulated Pim1 expression by binding to its promoter and activated MYC and mTORC1 signaling. PIM1 knockdown or pharmacological inhibition of mTORC1 signaling suppressed NB‐induced NIH3T3 cell transformation. Furthermore, NB enhanced the survival of human Jurkat T‐ALL cells by inactivating the pro‐apoptotic protein BCL2‐associated agonist of cell death (BAD). Conclusion: We demonstrated the pivotal role of NB in cell transformation and survival and identified PIM1as a key downstream target of NB. These findings propose a promising therapeutic strategy for patients with NB fusion‐positive leukemia. [ABSTRACT FROM AUTHOR]

Objective: PDZ‐binding kinase (PBK) has been reported as a poor prognostic factor and is a promising molecular target for anticancer therapeutics. Here, we aimed to investigate the effect of specific PBK inhibitor OTS514 on the survival of OSCC cells. Methods: Four OSCC cell lines (HSC‐2, HSC‐3, SAS, and OSC‐19) were used to examine the effect of OTS514 on cell survival and apoptosis. DNA microarray analysis was conducted to investigate the effect of OTS514 on gene expression in OSCC cells. Gene set enrichment analysis was performed to identify molecular signatures related to the antiproliferative effect of OTS514. Results: OTS514 decreased the cell survival of OSCC cells dose‐dependently, and administration of OTS514 readily suppressed the HSC‐2‐derived tumor growth in immunodeficient mice. Treatment with OTS514 significantly increased the number of apoptotic cells and caspase‐3/7 activity. Importantly, OTS514 suppressed the expression of E2F target genes with a marked decrease in protein levels of E2F1, a transcriptional factor. Moreover, TP53 knockdown attenuated OTS514‐induced apoptosis. Conclusion: OTS514 suppressed the proliferation of OSCC cells by downregulating the expression of E2F target genes and induced apoptosis by mediating the p53 signaling pathway. These results highlight the clinical application of PBK inhibitors in the development of molecular‐targeted therapeutics against OSCC. [ABSTRACT FROM AUTHOR]

CEBPA‐IGH, a fusion gene of the immunoglobulin heavy‐chain locus (IGH) and the CCAAT enhancer‐binding protein α (C/EBPα) gene, is recurrently found in B‐ALL cases and causes aberrant expression of C/EBPα, a master regulator of granulocyte differentiation, in B cells. Forced expression of C/EBPα in B cells was reported to cause loss of B‐cell identity due to the inhibition of Pax5, a master regulator of B‐cell differentiation; however, it is not known whether the same mechanism is applicable for B‐ALL development by CEBPA‐IGH. It is known that a full‐length isoform of C/EBPα, p42, promotes myeloid differentiation, whereas its N‐terminal truncated isoform, p30, inhibits myeloid differentiation through the inhibition of p42; however, the differential role between p42 and p30 in ALL development has not been clarified. In the present study, we examined the effect of the expression of p42 and p30 in B cells by performing RNA‐seq of mRNA from LCL stably transfected with p42 or p30. Unexpectedly, suppression of PAX5 target genes was barely observed. Instead, both isoforms suppressed the target genes of MEF2 family members (MEF2s), other regulators of B‐cell differentiation. Similarly, MEF2s target genes rather than PAX5 target genes were suppressed in CEBP‐IGH‐positive ALL (n = 8) compared with other B‐ALL (n = 315). Furthermore, binding of both isoforms to MEF2s target genes and the reduction of surrounding histone acetylation were observed in ChIP‐qPCR. Our data suggest that the inhibition of MEF2s by C/EBPα plays a role in the development of CEBPA‐IGH‐positive ALL and that both isoforms work co‐operatively to achieve it. [ABSTRACT FROM AUTHOR]

B‐cell acute lymphoblastic leukemia (B‐ALL), a genetically heterogeneous disease, is classified into different molecular subtypes that are defined by recurrent gene rearrangements, gross chromosomal abnormalities, or specific gene mutations. Cells with these genetic alterations acquire a leukemia‐initiating ability and show unique expression profiles. The distribution of B‐ALL molecular subtypes is greatly dependent on age, which also affects treatment responsiveness and long‐term survival, partly accounting for the inferior outcome in adolescents and young adults (AYA) and (older) adults with B‐ALL. Recent advances in sequencing technology, especially RNA sequencing and the application of these technologies in large B‐ALL cohorts have uncovered B‐ALL molecular subtypes prevalent in AYA and adults. These new insights supply more precise estimations of prognoses and targeted therapies informed by sequencing results, as well as a deeper understanding of the genetic basis of AYA/adult B‐ALL. This article provides an account of these technological advances and an overview of the recent major findings of B‐ALL molecular subtypes in adults. [ABSTRACT FROM AUTHOR]

B cells play a central role in immune system function. Deregulation of normal B cell maturation can lead to the development of autoimmune syndromes as well as B cell malignancies. [...]

ABSTRACT Background AML1/RUNX1 is the most frequently mutated gene in leukaemia and is central to the normal biology of hematopoietic stem and progenitor cells. However, the role of different AML1 [...]