Upregulated ATF1 Promotes Lipopolysaccharide Induced Inflammatory Response and Inhibits Osteogenic Differentiation of Human Periodontal Ligament Cells by Regulating NF-κB Pathway.

BACKGROUND: Periodontitis is a chronic inflammatory disease resulting from bacterial plaque infection. While the involvement of activating transcription factor 1 (ATF1) has been extensively explored in various human diseases, its specific role in periodontitis remains unclear. This study aims to elucidate the expression and biological function of ATF1 in the context of periodontitis. METHODS: Primary human periodontal ligament cells (hPDLCs) were procured from clinical samples and subsequently characterized. Following treatment with P. gingivalis lipopolysaccharide (LPS, 10 µg/mL), hPDLCs underwent transfection with either ATF1 vector or siRNA. The expression levels of ATF1 in LPS-treated hPDLCs or transfected cells were evaluated through real-time quantitative polymerase chain reaction (RT-qPCR) and western blot assay. Inflammatory factors, including interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-α), and interleukin-1beta (IL-1ß), were quantified using Enzyme-linked Immunosorbent Assay (ELISA). The assessment of osteogenic proteins, such as runt-related transcription factor 2 (Runx2), osteopontin (OPN), and osteoprotegerin (OPG), as well as noncanonical nuclear factor-kappaB (NF-κB) pathway-related proteins (p65, p-p65, IkBα, p-IkBα), was conducted using western blot assay. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and flow cytometry assays were employed to detect cell viability. RESULTS: LPS induced an inflammatory response and hindered the osteogenic differentiation of hPDLCs (p < 0.05, p < 0.01). Furthermore, ATF1 silencing enhanced cell proliferation and suppressed apoptosis in LPS-stimulated hPDLCs (p < 0.05, p < 0.01). ATF1 silencing not only restrained the inflammatory response but also promoted the osteogenic differentiation of LPS-stimulated hPDLCs (p < 0.05, p < 0.01). Importantly, ATF1 silencing effectively blocked the LPS-induced activation of the NF-κB signaling pathway (p < 0.05, p < 0.01, p < 0.001). CONCLUSIONS: ATF1 emerges as a promising treatment option, inhibiting the osteogenic differentiation of hPDLCs and mitigating the inflammatory response by preventing the phosphorylation of the NF-κB signaling pathway.

ATF1 promotes the malignancy of lung adenocarcinoma cells by transcriptionally regulating ZNF143 expression.

The clinical oncogenic functions and mechanisms of activating transcription factor 1 (ATF1) in the progression of lung adenocarcinoma have not been completely elucidated. In this study, by employing human lung adenocarcinoma tissues and cells, we detect the correlation of ATF1 expression with the clinicopathological features and prognosis of patients with lung adenocarcinoma and find that ATF1 promotes lung adenocarcinoma cell proliferation and migration by transcriptionally enhancing zinc finger protein 143 (ZNF143) expression. ATF1 and ZNF143 are strongly expressed in lung adenocarcinoma tissues compared with those in the adjacent normal tissues, and high ATF1 and ZNF143 expressions are related to poor disease-free survival of lung adenocarcinoma patients. ATF1 overexpression results in increased proliferation and migration of lung adenocarcinoma cells, whereas knockdown of ATF1 inhibits cell proliferation and migration. Furthermore, ATF1 transcriptionally regulates the expression of ZNF143, and ATF1 and ZNF143 expressions are positively correlated in lung adenocarcinoma tissues. ZNF143 knockdown blocks lung adenocarcinoma cell migration, which is mediated by ATF1 upregulation. Hence, this study provides a potential therapeutic candidate for the treatment of lung adenocarcinoma.

Protein arginine methyltransferase 5 is essential for oncogene product EWSR1-ATF1-mediated gene transcription in clear cell sarcoma.

Transcription dysregulation is common in sarcomas driven by oncogenic transcription factors. Clear cell sarcoma of soft tissue (CCSST) is a rare sarcoma with poor prognosis presently with no therapy. It is characterized by a balanced t(12;22) (q13;q12) chromosomal translocation, resulting in a fusion of the Ewing's sarcoma gene EWSR1 with activating transcription factor 1 (ATF1) to give an oncogene EWSR1-ATF1. Unlike normal ATF1, whose transcription activity is dependent on phosphorylation, EWSR1-ATF1 is constitutively active to drive ATF1-dependent gene transcription to cause tumorigenesis. No EWSR1-ATF1-targeted therapies have been identified due to the challenges in targeting intracellular transcription factors. Through proteomics screening to identify potential druggable targets for CCSST, we discovered protein arginine methyltransferase 5 (PRMT5) as a novel protein to interact with EWSR1-ATF1. PRMT5 is a type II protein arginine methyltransferase to symmetrically dimethylate arginine residues in substrate proteins to regulate a diverse range of activities including gene transcription, RNA splicing, and DNA repair. We found that PRMT5 enhances EWSR1-ATF1-mediated gene transcription to sustain CCSST cell proliferation. Genetic silencing of PRMT5 in CCSST cells resulted in severely impaired cell proliferation and EWSR1-ATF1-driven transcription. Furthermore, we demonstrate that the clinical-stage PRMT5 inhibitor JNJ-64619178 potently and efficaciously inhibited CCSST cell growth in vitro and in vivo. These results provide new insights into PRMT5 as a transcription regulator and warrant JNJ-64619178 for further clinical development to treat CCSST patients.

Phosphorylated ATF1 at Thr184 promotes metastasis and regulates MMP2 expression in gastric cancer.

BACKGROUND: Studies have revealed an important role of activating transcription factor 1 (ATF1) and phosphorylated ATF1 at Ser63 in tumors. Our previous study identified Thr184 as a novel phosphorylation site of ATF1. However, the role of phosphorylated ATF1 at Thr184 (p-ATF1-T184) in tumor is unclear. This study figured out the role of p-ATF1-T184 in the metastasis of gastric cancer (GC) and in the regulation of Matrix metallopeptidase 2 (MMP2). METHODS: Immunohistochemical analysis (IHC) was performed to analyze the level of p-ATF1-T184 and its relationship with clinicopathological characteristics. Wound scratch test, Transwell assay were used to observe the role of p-ATF1-T184 in the invasion and metastasis of GC. The regulation of MMP2 by p-ATF1-T184 was investigated by a series of experiments including quantitative RT-PCR, western blot, gelatin zymography assay, Chromatin immunoprecipitation (ChIP), luciferase reporter assay and cycloheximide experiment. The Cancer Genome Atlas (TCGA) data were used to analyze the expression and prognostic role of ATF1 and MMP2 in GC. Mass spectrometry (MS) following co-immunoprecipitation (co-IP) assay was performed to identify potential upstream kinases that would phosphorylate ATF1 at Thr184. RESULTS: High expression level of p-ATF1-T184 was found and significantly associated with lymph node metastasis and poor survival in a GC cohort of 126 patients. P-ATF1-T184 promoted migration and invasion of gastric cancer cells. Phosphorylation of ATF1-T184 could regulate the mRNA, protein expression and extracellular activity of MMP2. P-ATF1-T184 further increased the DNA binding ability, transcription activity, and stabilized the protein expression of ATF1. Moreover, TCGA data and IHC results suggested that the mRNA level of ATF1 and MMP2, and protein level of p-ATF1-T184 and MMP2 could be prognosis markers of GC. Two protein kinase related genes, LRBA and S100A8, were identified to be correlated with the expression ATF1 in GC. CONCLUSION: Our results indicated that p-ATF1-T184 promoted metastasis of GC by regulating MMP2.

Circ_0000745 Promotes the Progression of Cervical Cancer by Regulating miR-409-3p/ATF1 Axis.

Background: Cervical cancer (CC) is a common gynecological malignancy with a high risk of recurrence and death. Circular RNAs play a crucial role in the occurrence and development of tumors. This study aimed to investigate the function and mechanism of circ_0000745 in CC. Materials and Methods: The levels of circ_0000745, miR-409-3p, and activating transcription factor 1 (ATF1) were determined by quantitative real-time polymerase chain reaction or Western blot assay. Cell proliferation was assessed by colony formation assay. Cell migration and invasion were evaluated by transwell assay. Glycolysis was analyzed by measuring extracellular acidification rate, glucose uptake, and lactate production. Also, the protein levels of glucose transporter 1 and lactate dehydrogenase A were detected using Western blot. The relationship among circ_0000745, miR-409-3p, and ATF1 were confirmed by dual-luciferase reporter assay. Moreover, xenograft assay was performed to analyze tumor growth in vivo. Results: Circ_0000745 and ATF1 were upregulated, whereas miR-409-3p was downregulated in CC tissues and cells. Knockdown of circ_0000745 repressed proliferation, migration, invasion, and glycolysis of CC cells. Circ_0000745 regulated CC progression by targeting miR-409-3p. Circ_0000745 modulated ATF1 expression through sponging miR-409-3p. MiR-409-3p hindered CC progression by targeting ATF1. Furthermore, depletion of circ_0000745 impeded tumor growth in vivo. Conclusion: Circ_0000745 promoted the progression of CC through modulating miR-409-3p/ATF1 axis, indicating a promising biomarker for CC therapy.

Colorectal cancer risk variant rs7017386 modulates two oncogenic lncRNAs expression via ATF1-mediated long-range chromatin loop.

The activating transcription factor 1 (ATF1) has been identified as a vital pathogenic factor in the progression of colorectal cancer (CRC), whiles, the precise regulatory mechanisms remain elusive. Here, we comprehensively characterized the ATF1 cistrome by RNA-seq and ChIP-seq assays in CRC cell lines. As the results, we identified 358 genes differentially regulated and 15,029 ATF1 binding sites and demonstrated that ATF1 was widely involved in major signaling pathways in CRC, such as Wnt, TNF, Jak-STAT. Subsequently, by the expression quantitative trait loci (eQTL) analyses, we found that rs7017386 was associated with the expression of CCAT1 and PVT1 in the Wnt pathway. By a two-stage population study with 6,131 CRC cases and 10,022 healthy controls, we identified the variant was associated with CRC risk. Mechanistically, we found rs7017386 allele-specifically enhanced the binding affinity of ATF1 and promoted the expressions of PVT1 and CCAT1, via forming a long-range chromatin loop. Moreover, those two lncRNAs could synergistically facilitate c-Myc expression to activate the Wnt pathway in CRC progression. Our findings not only demonstrated the transcriptomic profiling of ATF1 in CRC, but also provided important clues for the etiology of CRC.

Integrative sequencing discovers an ATF1-motif enriched molecular signature that differentiates hyalinizing clear cell carcinoma from mucoepidemoid carcinoma.

OBJECTIVES: Salivary gland tumors are comprised of a diverse group of malignancies with widely varying prognoses. These cancers can be difficult to differentiate, especially in cases with limited potential for immunohistochemistry (IHC)-based characterization. Here, we sought to define the molecular profile of a rare salivary gland cancer called hyalinizing clear cell carcinoma (HCCC), and identify a molecular gene signature capable of distinguishing between HCCC and the histopathologically similar disease, mucoepidermoid carcinoma (MEC). MATERIALS AND METHODS: We performed the first integrated full characterization of five independent HCCC cases. RESULTS: We discovered insulin-like growth factor alterations and aberrant IGF2 and/or IGF1R expression in HCCC tumors, suggesting a potential dependence on this pathway. Further, we identified a 354 gene signature that differentiated HCCC from MEC, and was significantly enriched for genes with an ATF1 binding motif in their promoters, supporting a transcriptional pathogenic mechanism of the characteristic EWSR1-ATF1 fusion found in these tumors. Of the differentially expressed genes, IGF1R, SGK1 and SGK3 were found to be elevated in the HCCCs relative to MECs. Finally, analysis of immune checkpoints and subsequent IHC demonstrated that CXCR4 protein was elevated in several of the HCCC cases. CONCLUSION: Collectively, our data identify an ATF1-motif enriched gene signature that may have clinical utility for molecular differentiation of HCCCs from other salivary gland tumors and discover potential actionable alterations that may benefit the clinical care of recurrent HCCC patients.

NEDD4 triggers FOXA1 ubiquitination and promotes colon cancer progression under microRNA-340-5p suppression and ATF1 upregulation.

NEDD4 is an E3 ubiquitin ligase that recognizes substrates through protein-protein interactions and is involved in cancer development. This study aimed to elucidate the function of NEDD4 in colon cancer (CC) progression and its mechanism of action. NEDD4 was abundantly expressed in CC tissues and cells, and the overexpression of NEDD4 promoted the growth and metastasis of xenograft tumours as well as the tumorigenesis rate of primary CC in mouse models. In in vitro experiments, the silencing (or upregulation) of NEDD4 inhibited (or increased) the viability, invasion, and epithelial-to-mesenchymal transition of CC cells. The binding relationships between NEDD4 and FOXA1, FOXA1 and microRNA (miRNA)-340-5p, and miR-340-5p and ATF1 were validated by Co-immunoprecipitation, chromatin immunoprecipitation and luciferase assays, and NEDD4 was demonstrated to trigger FOXA1 ubiquitination and degradation. FOXA1 transcriptionally activated miR-340-5p, which subsequently bound to ATF1 mRNA. The upregulation of FOXA1 or miR-340-5p or the downregulation of ATF1 blocked certain functions of NEDD4 in CC cells. Altogether, NEDD4 was demonstrated to trigger FOXA1 ubiquitination and promote CC progression under the involvement of microRNA-340-5p suppression and ATF1 upregulation.

Primary Clear Cell Sarcoma of the Ileum: A Case Report With Next-Generation Sequencing Analysis.

As the concept of clear cell sarcoma-like tumor or malignant gastrointestinal neuroectodermal tumor (CCS-LT/MGNET) has been widely accepted, primary CCS of the gastrointestinal tract (CCS-GI) is becoming a rare entity. In this article, we describe a case of primary CCS-GI that occurred in the ileum of a 65-year-old male to further illustrate its rare occurrence. Similar to CCS of soft tissue (CCS-ST), the tumor was composed of spindled to epithelioid cells displaying fascicular, nested, or pseudopapillary arrangement. The tumor cells had large round to ovoid nuclei with vesicular chromatin and prominent nucleoli, containing eosinophilic to pale cytoplasm. In contrast to CCS-LT/MGNET, immunohistochemical study also showed variable positivity of HMB45, melan A, and MiTF besides the strong and diffuse staining of S100 protein and SOX10. Fluorescence in situ hybridization (FISH) using fusion probes identified EWSR1 and ATF1 genes rearrangement. Next-generation sequencing (NGS) analysis further revealed EWSR1 exons9/8-ATF1 exon4 and ATF1 exon3- EWSR1 exon11 fusion genes. CCS-GI and CCS-LT/MGNET possibly represent 2 related entities of the same spectrum, which differentiate along 2 different pathways.

Intracranial angiomatoid fibrous histiocytoma with rhabdoid features: a mimic of rhabdoid meningioma.

Angiomatoid fibrous histiocytoma (AFH) is an uncommon soft-tissue neoplasm that arises mostly in the extremities of young people and generally carries a good prognosis. Intracranial location is unusual and frequently associated with myxoid change. EWSR1 gene fusions with members of the CREB family (CREB1, ATF1, and CREM) are well-established events in AFH. These fusions have also been described in other neoplasms including intracranial myxoid mesenchymal tumor, and it is still uncertain whether the latter is a distinct entity or if it represents a myxoid variant of AFH. Here, we describe a rare falcine AFH presenting in a 50-year-old woman. The most striking feature of this tumor was its diffuse rhabdoid morphology with focal high mitotic activity, raising the consideration of rhabdoid meningioma (WHO grade III). The tumor cells were moderately positive for EMA and negative for progesterone receptor and SSTR2 prompting additional studies. Desmin was strongly positive and CD99 showed membranous immunoreactivity. BAP1, INI-1, and BRG1 expressions were retained. Next-generation sequencing analysis demonstrated an EWSR1-ATF1 gene fusion, supporting the diagnosis of an unusual rhabdoid variant of AFH. After gross total resection of this tumor, the patient remains free of disease 5 months after the surgery without additional treatment.

BRCA1/ATF1-Mediated Transactivation is Involved in Resistance to PARP Inhibitors and Cisplatin.

Homologous recombination (HR)-deficient cells are sensitive to PARP inhibitors through a synthetic lethal effect. We previously developed an HR activity assay named Assay of Site-Specific HR Activity (ASHRA). Here, we evaluated the HR activity of 30 missense variants of BRCA1 by ASHRA and found that several BRCA1 variants showed intermediate HR activity, which was not clearly discerned by our previous analyses using a conventional method. HR activity measured by ASHRA was significantly correlated with sensitivity to olaparib. However, cells expressing the severely HR-deficient BRCA1-C61G variant were resistant to olaparib, and resistance was dependent on high expression of activating transcription factor 1 (ATF1), which binds to BRCA1 and activates the transcription of target genes to regulate cell proliferation. The BRCA1-C61G variant bound to ATF1 and stimulated ATF1-mediated transactivation similar to wild-type BRCA1. High expression of ATF1 conferred resistance to olaparib and cisplatin activating BRCA1/ATF1-mediated transcription without affecting HR activity in BRCA2-knockdown or RAD51-knockdown cells, but not in BRCA1-knockdown cells. These results suggest that ASHRA is a useful method to evaluate HR activity in cells and to predict the sensitivity to PARP inhibitors. The expression level of ATF1 might be an important biomarker of the effect of PARP inhibitors and platinum agents on HR-deficient tumors with the BRCA1-C61G variant or alteration of non-BRCA1 HR factors such as BRCA2 and RAD51. Significance: ASHRA could evaluate HR activity in cells and predict the sensitivity to PARP inhibitors. High expression level of ATF1 may predict the resistance of BRCAness tumors with alterations of non-BRCA1 HR factors to PARP inhibitors and platinum agents.

Metformin directly suppresses atherosclerosis in normoglycaemic mice via haematopoietic adenosine monophosphate-activated protein kinase.

AIMS: Atherosclerotic vascular disease has an inflammatory pathogenesis. Heme from intraplaque haemorrhage may drive a protective and pro-resolving macrophage M2-like phenotype, Mhem, via AMPK and activating transcription factor 1 (ATF1). The antidiabetic drug metformin may also activate AMPK-dependent signalling. Hypothesis: Metformin systematically induces atheroprotective genes in macrophages via AMPK and ATF1, thereby suppresses atherogenesis. METHODS AND RESULTS: Normoglycaemic Ldlr-/- hyperlipidaemic mice were treated with oral metformin, which profoundly suppressed atherosclerotic lesion development (P < 5 × 10-11). Bone marrow transplantation from AMPK-deficient mice demonstrated that metformin-related atheroprotection required haematopoietic AMPK [analysis of variance (ANOVA), P < 0.03]. Metformin at a clinically relevant concentration (10 µM) evoked AMPK-dependent and ATF1-dependent increases in Hmox1, Nr1h2 (Lxrb), Abca1, Apoe, Igf1, and Pdgf, increases in several M2-markers and decreases in Nos2, in murine bone marrow macrophages. Similar effects were seen in human blood-derived macrophages, in which metformin-induced protective genes and M2-like genes, suppressible by si-ATF1-mediated knockdown. Microarray analysis comparing metformin with heme in human macrophages indicated that the transcriptomic effects of metformin were related to those of heme, but not identical. Metformin-induced lesional macrophage expression of p-AMPK, p-ATF1, and downstream M2-like protective effects. CONCLUSION: Metformin activates a conserved AMPK-ATF1-M2-like pathway in mouse and human macrophages, and results in highly suppressed atherogenesis in hyperlipidaemic mice via haematopoietic AMPK.

LINC00665/miR-9-5p/ATF1 is a novel axis involved in the progression of colorectal cancer.

Long noncoding RNAs (lncRNAs) are abnormally expressed in many malignant tumors and involved in regulating the malignant phenotypes of cancer cells. However, the role of LINC00665 in colorectal cancer (CRC) and its regulatory mechanism remain unclear. In this study, real-time polymerase chain reaction (RT-PCR) was used to detect the expressions of LINC00665, miR-9-5p and activating transcription factor 1 (ATF1) mRNA in CRC tissues. The expression of ATF1 in CRC tissues was also detected by immunohistochemistry and Western blot. CCK-8 and colony formation assays were employed to detect cell proliferation. Cell cycle and apoptosis were detected by flow cytometry analysis. Scratch healing assay and Transwell test were exploited to detect cell migration and invasion. The targeting relationships between LINC00665 and miR-9-5p, and miR-9-5p and ATF1 were validated by dual luciferase reporter assay. We found that LINC00665 was significantly overexpressed in CRC tissues, and it was also negatively correlated with the expression of miR-9-5p and positively associated with the expression of ATF1. Besides, LINC00665 promoted the proliferation, migration and invasion of CRC cells, and inhibited cell apoptosis by sponging miR-9-5p. ATF1 was proved to be the downstream target of miR-9-5p and was indirectly regulated by LINC00665. Collectively, it is concluded that LINC00665 contributes to the progression of CRC by regulating miR-9-5p/ATF1 axis.

Hematoma Resolution In Vivo Is Directed by Activating Transcription Factor 1.

RATIONALE: The efficient resolution of tissue hemorrhage is an important homeostatic function. In human macrophages in vitro, heme activates an AMPK (AMP-activated protein kinase)/ATF1 (activating transcription factor-1) pathway that directs Mhem macrophages through coregulation of HO-1 (heme oxygenase-1; HMOX1) and lipid homeostasis genes. OBJECTIVE: We asked whether this pathway had an in vivo role in mice. METHODS AND RESULTS: Perifemoral hematomas were used as a model of hematoma resolution. In mouse bone marrow-derived macrophages, heme induced HO-1, lipid regulatory genes including LXR (lipid X receptor), the growth factor IGF1 (insulin-like growth factor-1), and the splenic red pulp macrophage gene Spic. This response was lost in bone marrow-derived macrophages from mice deficient in AMPK (Prkab1-/-) or ATF1 (Atf1-/-). In vivo, femoral hematomas resolved completely between days 8 and 9 in littermate control mice (n=12), but were still present at day 9 in mice deficient in either AMPK (Prkab1-/-) or ATF1 (Atf1-/-; n=6 each). Residual hematomas were accompanied by increased macrophage infiltration, inflammatory activation and oxidative stress. We also found that fluorescent lipids and a fluorescent iron-analog were trafficked to lipid-laden and iron-laden macrophages respectively. Moreover erythrocyte iron and lipid abnormally colocalized in the same macrophages in Atf1-/- mice. Therefore, iron-lipid separation was Atf1-dependent. CONCLUSIONS: Taken together, these data demonstrate that both AMPK and ATF1 are required for normal hematoma resolution. Graphic Abstract: An online graphic abstract is available for this article.

Adult Intracranial Myxoid Mesenchymal Tumor with EWSR1-ATF1 Gene Fusion.

BACKGROUND: Intracranial myxoid mesenchymal tumors (IMMTs) carrying an EWSR1-CREB gene family fusion are extremely rare and have only been identified in 10 previous reports. All but one has been found in children or young adults. Although there appear to be similarities to a myxoid variant of angiomatoid fibrous histiocytoma (AFH), clear histologic differences exist that appear to distinguish IMMTs as a distinct and novel entity. Previous reports have lacked detailed long-term follow-up and recommendations regarding treatment approach. CASE DESCRIPTION: This case describes a 48-year-old woman who presented with a left intraventricular mass that was identified on histology as an IMMT with an EWSR1-ATF1 gene fusion. After initial resection, the tumor demonstrated local recurrence. Repeat resection was performed followed by immediate demonstration of local and distant tumor recurrence. Histologic analysis of the tumor demonstrated a myxoid mesenchymal tumor distinct from AFH. Fractionated stereotactic radiation therapy was administered after the second resection, and tumor control was achieved at 1 year. CONCLUSIONS: Intracranial myxoid mesenchymal tumor is a novel and rare entity that has been previously identified in only 10 cases. This case is particularly remarkable because it is only the second IMMT case to occur in a middle-aged adult and shares striking similarities in clinical presentation to the previously reported case. Given the aggressive recurrence seen with the presented case, we recommend the treatment plan to be surgical resection followed by adjuvant radiation therapy.

Intracranial Myxoid Mesenchymal Tumor With EWSR1-ATF1 Fusion.

Angiomatoid fibrous histiocytoma (AFH) is a rare soft tissue tumor that arises primarily in the extremities of young adults. Recurrent gene fusions involving EWSR1 with members of the cAMP response element binding protein (CREB) family have been reported in a diverse group of tumors, including AFH. AFH-like lesions have been reported to occur intracranially and the reported cases show low proliferation indices, frequently have a connection with the dura, and show recurrent EWSR1 rearrangements. These tumors have been termed intracranial myxoid mesenchymal tumor with EWSR1-CREB family gene fusions. A literature search identified 11 reported cases of intracranial AFH-like lesions with an EWSR1 rearrangement. Here, we report a case of intracranial myxoid mesenchymal tumor with an EWSR1-ATF1 fusion in an adult patient, and review the existing literature on this recently described entity.

Cell-type dependent enhancer binding of the EWS/ATF1 fusion gene in clear cell sarcomas.

Clear cell sarcoma (CCS) is a rare soft tissue sarcoma caused by the EWS/ATF1 fusion gene. Here, we established induced pluripotent stem cells (iPSCs) from EWS/ATF1-controllable murine CCS cells harboring sarcoma-associated genetic abnormalities. Sarcoma-iPSC mice develop secondary sarcomas immediately after EWS/ATF1 induction, but only in soft tissue. EWS/ATF1 expression induces oncogene-induced senescence in most cell types in sarcoma-iPSC mice but prevents it in sarcoma cells. We identify Tppp3-expressing cells in peripheral nerves as a cell-of-origin for these sarcomas. We show cell type-specific recruitment of EWS/ATF1 to enhancer regions in CCS cells. Finally, epigenetic silencing at these enhancers induces senescence and inhibits CCS cell growth through altered EWS/ATF1 binding. Together, we propose that distinct responses to premature senescence are the basis for the cell type-specificity of cancer development.

Systematic Functional Interrogation of Genes in GWAS Loci Identified ATF1 as a Key Driver in Colorectal Cancer Modulated by a Promoter-Enhancer Interaction.

Genome-wide association studies (GWASs) have identified approximately 100 colorectal cancer (CRC) risk loci. However, the causal genes in these loci have not been systematically interrogated. We conducted a high-throughput RNA-interference functional screen to identify the genes essential for proliferation in the CRC risk loci of Asian populations. We found that ATF1, located in the 12q13.12 region, functions as an oncogene that facilitates cell proliferation; ATF1 has the most significant effect of the identified genes and promotes CRC xenograft growth by affecting cell apoptosis. Next, by integrating a fine-mapping analysis, a two-stage affected-control study consisting of 6,213 affected individuals and 10,388 controls, and multipronged experiments, we elucidated that two risk variants, dbSNP: rs61926301 and dbSNP: rs7959129, that located in the ATF1 promoter and first intron, respectively, facilitate a promoter-enhancer interaction, mediated by the synergy of SP1 and GATA3, to upregulate ATF1 expression, thus synergistically predisposing to CRC risk (OR = 1.77, 95% CI = 1.42-2.21, p = 3.16 × 10-7; Pmultiplicative-interaction = 1.20 × 10-22; Padditive-interaction = 6.50 × 10-3). Finally, we performed RNA-seq and ChIP-seq assays in CRC cells treated with ATF1 overexpression in order to dissect the target programs of ATF1. Results showed that ATF1 activates a subset of genes, including BRAF, NRAS, MYC, BIRC2, DAAM1, MAML2, STAT1, ID1, and NKD2, related to apoptosis, Wnt, TGF-ß, and MAPK pathways, and these effects could cooperatively increase the risk of CRC. These findings reveal the clinical potential of ATF1 in CRC development and illuminate a promoter-enhancer interaction module between the ATF1 regulatory elements dbSNP: rs61926301 and dbSNP: rs7959129, and they bring us closer to understanding the molecular drivers of cancer.

The human ATF1 rs11169571 polymorphism associated with risk of nasopharyngeal carcinoma in Southern Chinese populations.

Our previous work reported activating transcription factor 1 (ATF1) is a promotive factor of nasopharyngeal carcinoma (NPC) tumorigenesis. This study is to further explore the association between the human ATF1 rs11169571 polymorphism and the risk of NPC occurrence. The association between ATF1 rs11169571 and risk of NPC occurrence was investigated in clinical samples of 560 patients and 661 controls obtained from southern China with high incidence of NPC. The genotypes were detected by PCR-RFLP. The differential expression activity of alleles -T and -C was analyzed with CNE-2 and C666-1 cells by luciferase reporter assay. Our data suggested that the allelic frequency and genotypes were significantly different between patients and controls. Compared to the TT homozygote, the TC and CC genotypes have been shown to be significantly decreased in NPC patients (OR = 0.494, 95% CI = 0.387-0.629, P < 0.001 and OR = 0.556, 95% CI = 0.364-0.851, P = 0.007, respectively). Compared to the -T allele, the -C allele is a factor of decreased risk in NPC (OR = 0.642, 95% CI = 0.537-0.767, P < 0.001). Luciferase reporter activity revealed that the -T allele confers a higher expression activity than the -C allele in CNE2 cells and C666-1 cells. In conclusion, ATF1 rs11169571 which could affect the expression of ATF1 is associated with NPC risk.