Upregulation of far upstream element-binding protein 1 (FUBP1) promotes tumor proliferation and unfavorable prognosis in tongue squamous cell carcinoma

FUBP1 in human cancer: Characteristics, functions, and potential applications

Far upstream element-binding protein 1 (FUBP1) is a single-stranded nucleic acid-binding protein that binds to the Far Upstream Element (FUSE) sequence and is involved in important biological processes, including DNA transcription, RNA biogenesis, and translation. Recent studies have highlighted the significance of aberrant expression or mutations in FUBP1 in the development of various tumors, with FUBP1 overexpression often indicating oncogenic roles in different tumor types. However, it is worth noting that recent research has discovered its tumor-suppressive role in cancer, which is not yet fully understood and appears to be tissue- or context-dependent. This review summarizes the association between FUBP1 and diverse cancers and discusses the functions of FUBP1 in cancer. In addition, this review proposes potential clinical implications and outlines future research directions to pave the way for the development of targeted therapeutic strategies focusing on FUBP1.

Circulating autoantibodies to alpha-enolase (ENO1) and far upstream element-binding protein 1 (FUBP1) are negative prognostic factors for pancreatic cancer patient survival

Pancreatic ductal adenocarcinoma (PDA) has a dismal prognosis due to a lack of early diagnostic markers and effective therapy. In PDA patients, the glycolytic enzyme and plasminogen receptor alpha-enolase (ENO1) and the transcription factor far upstream element-binding protein 1 (FUBP1) are upregulated and elicit the production of autoantibodies (aAb) that discriminate healthy subjects from PDA patients, with the latter mostly directed to post-translational phosphorylated isoforms. Here, the correlation of prognosis with circulating ENO1 and FUBP1aAb, and their protein tissue expression was analyzed in PDA patients. Circulating ENO1 and FUBP1 aAb was analyzed in two cohorts of PDA patients by ELISA (n = 470), while tissues expression was observed by immunohistochemistry (n = 45). Overall survival (OS) was estimated using the Kaplan-Meier method, while the Cox model was used to estimate the hazard ratios (HR) adjusted for the main prognostic factors. Logistic models were applied to assess associations between death and its risk indicators. All statistical analyses were performed with Stata version 15. Unlike ENO1 aAb, there was a significant correlation between FUBP1 aAb and FUBP1 expression in tumors (p = 0.0268). In addition, we found that high ENO1 (p = 0.016) and intermediate FUBP1 aAb levels (p = 0.013) were unfavorable prognostic factors. Notably, it was found that high anti-FUBP1 aAb level is a good prognostic marker for tail-body PDA (p = 0.016). Our results suggest that different levels of circulating aAb to ENO1 and FUBP1 predict a poor outcome in PDA patients and can be used to improve therapeutic strategies.

Far upstream element -binding protein 1 (FUBP1) participates in the malignant process and glycolysis of colon cancer cells by combining with c-Myc

Human distal upstream element (Fuse) binding protein 1 (FUBP1) is a transcriptional regulator of c-Myc and represents an important prognostic marker in many cancers. Therefore, the present study aimed to investigate whether FUBP1 could combine with c-Myc to participate in the progression of colon cancer. Detection of FUBP1 expression was done through reverse transcription-quantitative PCR (RT-qPCR), and the combination of FUBP1 and c-Myc was detected by immunoprecipitation assay. Cell counting kit (CCK)-8, colony formation, transwell and wound healing were applied for assessing the ability of cells to proliferate, migrate, and invade; glycolysis and lactic acid detection kits were used to detect glucose uptake and lactic acid content, while western blotting was adopted to detect the protein expression of glycolysis-related genes. FUBP1 expression was elevated in HCT116 cells relative to other colon cancer cell lines, and silencing FUBP1 could inhibit the ability of HCT116 cells to proliferate, migrate, invade and glycolysis, and enhance its apoptosis. In addition, the results of immunoprecipitation experiments showed that FUBP1 could bind to c-Myc. c-Myc overexpression reversed the inhibitory effects of FUBP1 knockdown on the ability of HCT116 cells to proliferate, migrate, invade and glycolysis. The results indicated that FUBP1 could participate in the deterioration process of colon cancer cells by combining with c-Myc, and it has clinical significance for understanding the key role of FUBP1 in tumor genesis.

Pan-Cancer Transcriptome and Immune Infiltration Analyses Reveal the Oncogenic Role of Far Upstream Element-Binding Protein 1 (FUBP1)

Despite increasing evidence to support the relationship between FUBP1 and tumorigenesis in some types of cancers, there have been no analyses from a pan-cancer perspective. Here, we are the first to investigate the putative oncogenic role of FUBP1 in 33 cancer types based on The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Dysregulated FUBP1 expression was observed in most cancer types, and high FUBP1 expression suggests poor prognosis in cancers such as ACC, KICH, LIHC, LUAD, LUSC, SARC, CESC, and SKCM. Missense mutation is the most common type of FUBP1 mutation, and R430 in KH_4 is a predominant mutation site. Enhanced phosphorylation of FUBP1 at the S120 site has been observed in clear cell RCC, lung adenocarcinoma, and pediatric brain cancer specimens from African-American and Asian individuals. The expression of FUBP1 was found to be negatively correlated with the infiltration of CD8+ T lymphocytes in GBM, HNSC-HPV- and UCEC but positively correlated with that of tumor-associated fibroblasts in CESC, ESCA, HNSC, LIHC, LUAD, PAAD, and THYM. Furthermore, RNA splicing and spliceosome signaling were predominantly enriched in both GO and KEGG analyses of the functional mechanism of FUBP1. Briefly, this pan-cancer analysis comprehensively revealed the multifaceted characteristics and oncogenic role of FUBP1 in different human cancers.

FUBP1 mediates the growth and metastasis through TGFβ/Smad signaling in pancreatic adenocarcinoma

Recent studies have reported that the expression levels of far upstream element‑binding protein 1 (FUBP1) were upregulated and served a crucial role in several types of cancer. However, the underlying molecular mechanisms and clinical significance of FUBP1 in pancreatic adenocarcinoma (PAAD) remain unclear. The present study aimed to determine the expression levels of FUBP1 in patients with PAAD and subsequently investigated the biological functions and mechanisms of FUBP1 using in vitro assays. FUBP1 expression levels and survival outcomes in patients with PAAD were analyzed using The Cancer Genome Atlas and starBase databases. Reverse transcription‑quantitative PCR was used to analyze the mRNA expression levels of FUBP1 in PAAD and adjacent normal tissues. In addition, the expression of FUBP1 was knocked down with small interfering RNA and overexpressed using FUBP1‑overexpressed plasmids, and the effects on biological functions, including cell proliferation, migration and invasion, were investigated. Western blotting and immunofluorescence assays were used to determine the role of FUBP1 in epithelial‑mesenchymal transition (EMT). The results of the present study revealed that the expression levels of FUBP1 were upregulated in PAAD tissues compared with adjacent normal tissues and the upregulated expression was significantly associated with poor survival. The knockdown of FUBP1 expression significantly inhibited the proliferative, migratory and invasive abilities of the PAAD PaTu8988 cell line, while the overexpression of FUBP1 promoted cell proliferation, migration and invasion in the PAAD SW1990 cell line. Furthermore, the knockdown of FUBP1 downregulated the expression levels of EMT‑related markers, including N‑cadherin, β‑catenin and vimentin, while the expression levels of E‑cadherin were upregulated. The knockdown of FUBP1 was also revealed to regulate the TGFβ/Smad signaling cascade by downregulating phosphorylated‑Smad2/3 and TGFβ1 expression levels. Conversely, the overexpression of FUBP1 reversed these effects. In conclusion, the findings of the present study indicated that FUBP1 may be a potential oncogene that mediates the EMT of PAAD via TGFβ/Smad signaling. These data suggested that FUBP1 may represent a potential biomarker for the diagnosis of PAAD or a target for the treatment of patients with PAAD.

Overexpression of FUBP1 is associated with human cervical carcinoma development and prognosis

AIMS

Far upstream element-binding protein 1 (FUBP1) has been shown to involve in the tumorigenesis and tumor progression of various cancers. However, the expression and function of FUBP1 in cervical carcinoma remains unknown.

MAIN METHODS

Transcriptional expression of FUBP1 was initially evaluated using the Oncomine database, followed by evaluation of FUBP1 protein levels using immunohistochemistry in 119 cervical carcinoma patient tissues. In vitro experiments were performed to assess the tumorigenic role of FUBP1. Besides, Gene Set Enrichment Analysis, EnrichmentMap analysis, and protein-protein interaction (PPI) networks were used to evaluate the potential mechanisms of FUBP1 in promoting cervical cancer progression.

KEY FUNDINGS

In this research, we found both FUBP1 mRNA transcription and protein expression levels increased significantly in cervical carcinoma tissues compared with adjacent normal cervical tissues. Furthermore, elevated FUBP1 expression was positively correlated with age, T classification, N classification, tumor recurrence, Ki67 expression, and poor prognosis in cervical carcinoma patients. Besides, elevated FUBP1 expression acted as an independent unfavorable predictor for overall survival and disease-free survival in cervical carcinoma. Overexpression of FUBP1 significantly promoted cervical carcinoma cell proliferation and inhibits cell apoptosis in vitro, while knockdown of FUBP1 showed the opposite effect. Mechanistically, bioinformatics analysis revealed that FUBP1 promoted the biological function of cervical carcinoma cells via enhancing DNA repair signal pathways. Our results demonstrate for the first time that FUBP1 is a novel prognostic factor and therapeutic target for cervical carcinoma.