High ATF5 expression is a favorable prognostic indicator in patients with hepatocellular carcinoma after hepatectomy

Exploring Prognosis, Tumor Microenvironment and Tumor Immune Infiltration in Hepatocellular Carcinoma Based on ATF/CREB Transcription Factor Family Gene-Related Model

Introduction

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer. It is the fourth leading cause of cancer-related death worldwide. Deregulation of the ATF/CREB family is associated with the progression of metabolic homeostasis and cancer. Because the liver plays a central role in metabolic homeostasis, it is critical to assess the predictive value of the ATF/CREB family in the diagnosis and prognosis of HCC.

Methods

Using data from The Cancer Genome Atlas (TCGA), this research evaluated the expression, copy number variations, and frequency of somatic mutations of 21 genes in the ATF/CREB family in HCC. A prognostic model based on the ATF/CREB gene family was developed via Lasso and Cox regression analyses, with the TCGA cohort serving as the training dataset and the International Cancer Genome Consortium (ICGC) cohort serving as the validation set. Kaplan-Meier and receiver operating characteristic analyses verified the accuracy of the prognostic model. Furthermore, the association among the prognostic model, immune checkpoints, and immune cells was examined.

Results

High-risk patients exhibited an unfavorable outcome as opposed to those in the low-risk category. Multivariate Cox analysis revealed that the risk score calculated based on the prognostic model was an independent prognostic factor for HCC. Analysis of immune mechanisms revealed that the risk score had a positive link to the expression of immune checkpoints, particularly CD274, PDCD1, LAG3, and CTLA4. Differences in immune cells and immune-associated roles were found between the high- and low-risk patients, as determined by single-sample gene set enrichment analysis. The core genes ATF1, CREB1, and CREB3 in the prognostic model were shown to be upregulated in HCC tissues as opposed to adjoining normal tissues, and the 10-year overall survival (OS) rate was worse among patients with elevated expression levels of ATF1, CREB1, and CREB3. Elevated expression levels of ATF1, CREB1, and CREB3 in HCC tissues were confirmed by qRT-PCR and immunohistochemistry studies.

Conclusion

According to the results of our training set and test set, the risk model based on the six ATF/CREB gene signatures predicting prognosis has certain predictive accuracy in predicting the survival of HCC patients. This study provides novel insights into the individualized treatment of patients with HCC.

Advancements in Activating Transcription Factor 5 Function in Regulating Cell Stress and Survival

Activating transcription factor 5 (ATF5) belongs to the activating transcription factor/cyclic adenosine monophosphate (cAMP) response element-binding protein family of basic region leucine zipper transcription factors. ATF5 plays an important role in cell stress regulation and is involved in cell differentiation and survival, as well as centrosome maintenance and development. Accumulating evidence demonstrates that ATF5 plays an oncogenic role in cancer by regulating gene expressions involved in tumorigenesis and tumor survival. Recent studies have indicated that ATF5 may also modify the gene expressions involved in other diseases. This review explores in detail the regulation of ATF5 expression and signaling pathways and elucidates the role of ATF5 in cancer biology. Furthermore, an overview of putative therapeutic strategies that can be used for restoring aberrant ATF5 activity in different cancer types is provided.

ELF1 Transcription Factor Enhances the Progression of Glioma via ATF5 promoter

A key transcriptional activator, activating transcription factor 5 (ATF5), is aberrantly overexpressed in glioma and supports both poor prognosis and antiapototic potential. Unfortunately, data on ATF5 is largely based on its regulatory mechanism. Further investigation of the upstream regulatory factor for ATF5 transcription in glioma is required. Clinical data for patients with diagnosed glioma were obtained from The Cancer Genome Atlas (TCGA). Additionally, transcription factors potentially regulating the ATF5 promoter in glioma were screened with bioinformatics. A further experimental study was performed to investigate both the role of E74-like factor 1 (ELF1) and the binding of ELF1 and the ATF5 promoter in glioma. We show that ATF5 expression is upregulated in glioma tissues and associated with tumor malignancy and worse prognosis. As a putative upstream regulator, silencing ELF1 inhibits glioma cell growth and migration with ATF5 involvement. Moreover, ELF1 upregulation is also associated with poor prognosis in glioma. Importantly, the luciferase assay and chromatin immunoprecipitation (ChIP) reveal that the ATF5 gene promoter is essential for ELF1-dependent activation of ATF5 gene transcription. These results indicate that a high expression of ELF1 may be related to the malignant behavior of human glioma and ELF1 promotes glioma development mediated by transactivation of the ATF5 gene.

The transcription factor ATF5: role in cellular differentiation, stress responses, and cancer

Activating transcription factor 5 (ATF5) is a cellular prosurvival transcription factor within the basic leucine zipper (bZip) family that is involved in cellular differentiation and promotes cellular adaptation to stress. Recent studies have characterized the oncogenic role of ATF5 in the development of several different types of cancer, notably glioblastoma. Preclinical assessment of a systemically deliverable dominant-negative ATF5 (dnATF5) biologic has found that targeting ATF5 results in tumor regression and tumor growth inhibition of glioblastoma xenografts in mouse models. In this review, we comprehensively and critically detail the current scientific literature on ATF5 in the context of cellular differentiation, survival, and response to stressors in normal tissues. Furthermore, we will discuss how the prosurvival role of ATF5 aides in cancer development, followed by current advances in targeting ATF5 using dominant-negative biologics, and perspectives on future research.

Differential expression of two activating transcription factor 5 isoforms in papillary thyroid carcinoma

BACKGROUND

Activating transcription factor 5 (ATF5) is a member of the activating transcription/cAMP response element-binding protein family of basic leucine zipper proteins that plays an important role in cell survival, differentiation, proliferation, and apoptosis. The ATF5 gene generates two transcripts: ATF5 isoform 1 and ATF5 isoform 2. A number of studies indicate that ATF5 could be an attractive target for therapeutic intervention in several tumor types; however, so far, the role of ATF5 has not been investigated in papillary thyroid carcinoma (PTC).

METHODS

Quantitative real-time reverse transcription polymerase chain reaction and immuno-histochemical staining were used to study ATF5 mRNA and protein expression in PTC.

RESULTS

We report here that ATF5 is expressed more in PTC tissue than in normal thyroid tissue. Furthermore, this is the first study that describes the presence of both ATF5 isoforms in PTC.

CONCLUSION

These findings could provide potential applications in PTC cancer treatment.

DNA methylation level of promoter region of activating transcription factor 5 in glioma

Transcription factors, which represent an important class of proteins that play key roles in controlling cellular proliferation and cell cycle modulation, are attractive targets for cancer therapy. Previous researches have shown that the expression level of activating transcription factor 5 (ATF5) was frequently increased in glioma and its acetylation level was related to glioma. The purposes of this study were to explore the methylation level of ATF5 in clinical glioma tissues and to explore the effect of ATF5 methylation on the expression of ATF5 in glioma. Methylation of the promoter region of ATF5 was assayed by bisulfite-specific polymerase chain reaction (PCR) sequencing analysis in 35 cases of glioma and 5 normal tissues. Quantitative real-time PCR (qRT-PCR) was also performed to detect ATF5 mRNA expression in 35 cases of glioma and 5 normal tissues. Clinical data were collected from the patients and analyzed. The percentages of methylation of the ATF5 gene in the promoter region in healthy control, patients with well-differentiated glioma, and those with poorly differentiated glioma were 87.78%, 73.89%, and 47.70%, respectively. Analysis of the methylation status of the promoter region of the ATF5 gene showed a gradually decreased methylation level in poorly differentiated glioma, well-differentiated glioma, and normal tissues (P<0.05). There was also a significant difference between well-differentiated glioma and poorly differentiated glioma (P<0.05). ATF5 mRNA expression in glioma was significantly higher than that in the normal tissues (P<0.05). This study provides the first evidence that the methylation level of ATF5 decreased, and its mRNA expression was evidently up-regulated in glioma.