The novel human gene MIP functions as a co-activator of hMafF

A comprehensive pan-cancer examination of transcription factor MAFF: Oncogenic potential, prognostic relevance, and immune landscape dynamics

AIMS

Previous studies indicate that MAF BZIP Transcription Factor F (MAFF) facilitates ectopic metastasis and tumor cell migration. While its role in neoplasm progression is recognized, a thorough pan-cancer analysis of MAFF's impact remains pending.

MAIN METHODS

MAFF expression across normal and tumor tissues was analyzed using transcriptomic data from Genomic Data Commons (GDC) and UCSC XENA, with protein details from Human Protein Atlas (HPA) and GeneMANIA. Tumor Immune Single-cell Hub (TISCH) and Spatial Transcriptomics Omics DataBase (STOmics DB) identified MAFF expression in the tumor microenvironment (TME). MAFF's prognostic significance and immune-related gene associations were evaluated through univariate Cox regression, TIMER2.0 immune cell infiltration analysis, and Spearman correlation. Critical pathways were identified using Gene Set Enrichment Analysis (GSEA) and Gene Set Variation Analysis (GSVA), while molecular docking explored anticancer agent interactions.

KEY FINDINGS

MAFF expression varies across cancers, affecting tumor prognosis, notably in monocytes/macrophages and endothelial cells. Copy number variation (CNV) positively correlates with MAFF expression, while methylation shows inverse correlation. MAFF mutations significantly affect LGG patient prognosis and correlate with immune therapy responses. ESTIMATE and immune profiling linked MAFF to immunosuppression pathways. Molecular docking identified MAFF-targeted drugs, with validated effects on breast cancer and endometrial cancer cell survival and migration in vitro.

SIGNIFICANCE

Multi-omics analysis identified MAFF as a potential prognostic marker correlating with tumor immunity and microenvironment, suggesting its value for personalized cancer immunotherapy, particularly in BRCA and UCEC.

RBFOX1 Regulates the Permeability of the Blood-Tumor Barrier via the LINC00673/MAFF Pathway

The blood-tumor barrier limits the delivery of therapeutic drugs to brain tumor tissues. Selectively opening the blood-tumor barrier is considered crucial for effective chemotherapy of glioma. RNA-binding proteins have emerged as crucial regulators in various biologic processes. This study found that RNA-binding Fox-1 homolog 1 (RBFOX1) was downregulated in glioma vascular endothelial cells derived from glioma tissues, and in glioma endothelial cells obtained by co-culturing endothelial cells with glioma cells. Overexpression of RBFOX1 impaired the integrity of the blood-tumor barrier and increased its permeability. Additionally, RBFOX1 overexpression decreased the expression of tight junction proteins ZO-1, occludin, and claudin-5. Subsequent analysis of the mechanism indicated that the overexpression of RBFOX1 increased musculoaponeurotic fibrosarcoma protein basic leucine zipper [bZIP] transcription factor F (MAFF) expression by downregulating LINC00673, which stabilized MAFF messenger RNA (mRNA) through Staufen1-mediated mRNA decay. Moreover, MAFF could bind to the promoter region and inhibit the promoter activities of ZO-1, occludin, and claudin-5, which reduced its expression. The combination of RBFOX1 upregulation and LINC00673 downregulation promoted doxorubicin delivery across the blood-tumor barrier, resulting in apoptosis of glioma cells. In conclusion, this study indicated that overexpression of RBFOX1 increased blood-tumor barrier permeability through the LINC00673/MAFF pathway, which might provide a new useful target for future enhancement of blood-tumor barrier permeability.

The small MAF transcription factors MAFF, MAFG and MAFK: current knowledge and perspectives

The small MAFs, MAFF, MAFG and MAFK have emerged as crucial regulators of mammalian gene expression. Previous studies have linked small MAF function, by virtue of their heterodimerization with the Cap 'n' Collar (CNC) family of transcription factors, to the stress response and detoxification pathways. Recent analyses have revealed a complex regulatory network involving small MAF transcription factors and other cellular proteins. The expression and activity of small MAFs are tightly regulated at multiple levels. With regard to their clinical importance, small MAFs have been linked to various diseases, such as diabetes, neuronal disorders, thrombocytopenia and carcinogenesis. A better understanding of the molecular mechanisms governing the activity of small MAFs will provide novel insights into the control of mammalian transcription and may lead to the development of novel therapeutic strategies to treat common human disorders.

TREM-1 and DAP12 expression in monocytes of patients with severe psychiatric disorders. EGR3, ATF3 and PU.1 as important transcription factors

INTRODUCTION

Immune activation is a characteristic of schizophrenia (SCZ), bipolar disorder (BD) and unipolar major depressive disorder (MDD). The triggering receptor expressed on myeloid cells 1 (TREM-1), its' adaptor molecule DAP12 and their transcription factor (TF) PU.1 are important key genes in inflammation and expressed in activated monocytes and microglia.

AIM

To test: (1) if the expressions of TREM-1, DAP12 and PU.1 are increased in monocytes of patients with severe psychiatric disorders and (2) if PU.1 and the TFs ATF3 and EGR3 (which have been found as prominent increased monocyte genes in previous studies) are involved in the regulation of TREM-1 and DAP12 expression.

METHODS

Using Q-PCR, we studied the gene expression of TREM-1, DAP12, PU.1, ATF3 and EGR3 in the monocytes of 73 patients with severe psychiatric disorders (27 recent onset SCZ patients, 22 BD patients and 24 MDD patients) and of 79 healthy controls (HC). Using in silico TF binding site prediction and in vivo chromatin immunoprecipitation (ChIP), we studied the actual binding of EGR3, ATF3 and PU.1 to the promoter regions of TREM-1 and DAP12.

RESULTS

1. TREM-1 gene expression was increased in the monocytes of SCZ and BD patients and tended to be increased in the monocytes of MDD patients. 2. DAP12 gene levels were neither increased in the monocytes of SCZ, BD, nor MDD patients. 3. PU.1 expression levels were increased in the monocytes of MDD patients, but not in those of SCZ and BD patients. 4. TREM-1 expression levels correlated in particular to ATF3 and EGR3 expression levels, DAP12 expression levels correlated in particular to PU.1 expression levels. 5. We found using binding site prediction and ChIP assays that the TFs EGR3 and ATF3 indeed bound to the TREM-1 promoter, PU.1 bound to both the TREM-1 and DAP12 promoter.

CONCLUSION

In this study, we provide evidence that TREM-1 gene expression is significantly increased in monocytes of SCZ and BD patients and that the TREM-1 gene is a target gene of the TFs ATF3 and EGR3. In MDD patients, PU.1 gene expression was increased with a tendency for TREM-1 gene over expression. Our observations support the concept that monocytes are in a pro-inflammatory state in severe psychiatric conditions and suggest differences in monocyte inflammatory set points between SCZ, BD and MDD.

Small Maf proteins in mammalian gene control: mere dimerization partners or dynamic transcriptional regulators?

The small Maf basic leucine zipper (bZIP) proteins MafF, MafG and MafK, while modest in size, have emerged as crucial regulators of mammalian gene expression. Intriguingly, small Mafs do not contain an obvious transcriptional activation domain. However, previously perceived as "mere" partner molecules conferring DNA binding specificity to complexes with larger bZIP proteins, such as the CNC family member Nrf2, it has become clear that small Maf proteins are essential and dynamically regulated transcription factors. Current data suggest stringent control of small Maf protein function through transcriptional and post-translational mechanisms. Initial gene targeting experiments revealed considerable functional redundancy among small Maf proteins in vivo. This was not unexpected, due to the high level of homology among the three small Mafs. Nevertheless, further studies showed that these transcription factors have critical roles in various cellular processes, including stress signaling, hematopoiesis, CNS function and oncogenesis. Recent data provide a possible link between small Maf-mediated transcription and the inflammatory response.

Potential targets of FOXL2, a transcription factor involved in craniofacial and follicular development, identified by transcriptomics

FOXL2 is a gene encoding a forkhead transcription factor, whose mutations are responsible for the blepharophimosis-ptosis-epicanthus inversus syndrome that often involves premature ovarian failure. FOXL2 is one of the earliest ovarian markers and it offers, along with its targets, an excellent model to study ovarian development and function in normal and pathological conditions. We have recently shown that the aromatase gene is a target of FOXL2, and only three other targets have been reported so far. To detect potential transcriptional targets of FOXL2, we used DNA chips and quantitative PCR to compare the transcriptomes of granulosa-like cells overexpressing, or not, FOXL2. This analysis showed that mediators of inflammation, apoptotic and transcriptional regulators, genes involved in cholesterol metabolism, and genes encoding enzymes and transcription factors involved in reactive oxygen species detoxification were up-regulated. On the other hand, FOXL2 down-regulated the transcription of several genes involved in proteolysis and signal transduction and in transcription regulation. A bioinformatic analysis was conducted to discriminate between potential target promoters activated and repressed by FOXL2. In addition, the promoters of strongly activated genes were enriched in forkhead recognition sites, suggesting that these genes might be direct FOXL2 targets. Altogether, these results provide insight into the activity of FOXL2 and may help in understanding the mechanisms of pathogenesis of FOXL2 mutations if the targets prove to be the same in the ovary.