Physical and functional interaction of the proto-oncogene EVI1 and tumor suppressor gene HIC1 deregulates Bcl-xL mediated block in apoptosis

Emerging Roles of PRDM Factors in Stem Cells and Neuronal System: Cofactor Dependent Regulation of PRDM3/16 and FOG1/2 (Novel PRDM Factors)

PRDI-BF1 (positive regulatory domain I-binding factor 1) and RIZ1 (retinoblastoma protein-interacting zinc finger gene 1) (PR) homologous domain containing (PRDM) transcription factors are expressed in neuronal and stem cell systems, and they exert multiple functions in a spatiotemporal manner. Therefore, it is believed that PRDM factors cooperate with a number of protein partners to regulate a critical set of genes required for maintenance of stem cell self-renewal and differentiation through genetic and epigenetic mechanisms. In this review, we summarize recent findings about the expression of PRDM factors and function in stem cell and neuronal systems with a focus on cofactor-dependent regulation of PRDM3/16 and FOG1/2. We put special attention on summarizing the effects of the PRDM proteins interaction with chromatin modulators (NuRD complex and CtBPs) on the stem cell characteristic and neuronal differentiation. Although PRDM factors are known to possess intrinsic enzyme activity, our literature analysis suggests that cofactor-dependent regulation of PRDM3/16 and FOG1/2 is also one of the important mechanisms to orchestrate bidirectional target gene regulation. Therefore, determining stem cell and neuronal-specific cofactors will help better understanding of PRDM3/16 and FOG1/2-controlled stem cell maintenance and neuronal differentiation. Finally, we discuss the clinical aspect of these PRDM factors in different diseases including cancer. Overall, this review will help further sharpen our knowledge of the function of the PRDM3/16 and FOG1/2 with hopes to open new research fields related to these factors in stem cell biology and neuroscience.

Multifaceted Role of PRDM Proteins in Human Cancer

The PR/SET domain family (PRDM) comprise a family of genes whose protein products share a conserved N-terminal PR [PRDI-BF1 (positive regulatory domain I-binding factor 1) and RIZ1 (retinoblastoma protein-interacting zinc finger gene 1)] homologous domain structurally and functionally similar to the catalytic SET [Su(var)3-9, enhancer-of-zeste and trithorax] domain of histone methyltransferases (HMTs). These genes are involved in epigenetic regulation of gene expression through their intrinsic HMTase activity or via interactions with other chromatin modifying enzymes. In this way they control a broad spectrum of biological processes, including proliferation and differentiation control, cell cycle progression, and maintenance of immune cell homeostasis. In cancer, tumor-specific dysfunctions of PRDM genes alter their expression by genetic and/or epigenetic modifications. A common characteristic of most PRDM genes is to encode for two main molecular variants with or without the PR domain. They are generated by either alternative splicing or alternative use of different promoters and play opposite roles, particularly in cancer where their imbalance can be often observed. In this scenario, PRDM proteins are involved in cancer onset, invasion, and metastasis and their altered expression is related to poor prognosis and clinical outcome. These functions strongly suggest their potential use in cancer management as diagnostic or prognostic tools and as new targets of therapeutic intervention.

Ecotropic viral integration site 1 regulates the progression of acute myeloid leukemia via MS4A3-mediated TGFβ/EMT signaling pathway

Acute myeloid leukemia (AML) is a type of malignant tumor that is caused by malignant clone hematopoietic stem cells. The ecotropic viral integration site 1 (Evi1) is a zinc finger transcription factor, which is highly expressed in AML, and its expression level has been associated with poor prognosis of AML. Previous studies have indicated that Evi1 may regulate cell proliferation, differentiation and apoptosis by inhibiting the membrane-spanning-4-domains subfamily-A member-3 (MS4A3) gene in AML. The aim of the present study was to investigate the role of Evi1 in the progression of AML. The results revealed that Evi1 was overexpressed in leukemia cells compared with normal T lymphocytes. MicroRNAs (miR)-133 and -431 that target Evi1 were investigated, and it was observed that there was a low expression of miR-431 in AML. The transfection of miR-431 was able to decrease the promoter methylation levels of the Evi1 gene in AML cells. The transfection of miR-431 also suppressed the migration and invasion of AML cells. The present study revealed that the transfection of miR-431 mimic was able to downregulate MS4A3 expression in AML cells. Furthermore, the expression levels of transforming growth factor β (TGFβ) and epithelial-to-mesenchymal transition (EMT) markers fibronectin, α-smooth muscle actin, and vimentin were downregulated following the transfection of miR-431 in AML cells. The overexpression of MS4A3 was also able to suppress miR-431-mediated inhibition of the expression of TGFβ and EMT markers in AML cells. The addition of TGFβ inhibited the downregulation of EMT markers by transfection of miR-431 in AML cells. The transfection of miR-431 suppressed the migration and invasion of AML cells, which was also abolished by the addition of TGFβ. In conclusion, the results of the present study indicated that Evi1 may be a potential molecular target of leukemia therapy via MS4A3-mediated TGFβ/EMT signaling pathway.