Pituitary Tumor Transforming Gene Research Articles

Pituitary tumor‑transforming gene 1 regulates the senescence and apoptosis of oral squamous cell carcinoma in a p21‑dependent DNA damage response manner.

Pituitary tumor‑transforming gene 1 (PTTG1), also known as securin, is a proto‑oncogene involved in the development of various cancers by promoting cell proliferation and mobility. However, its underlying biological mechanisms in oral squamous cell carcinoma (OSCC) progression remain unclear. in the present study, it was sought to elucidate the role of PTTG1 as an oncogene in OSCC progression and was attempted to unravel the underlying mechanism and impact of PTTG1 expression on cell cycle, cell death, and cellular senescence. The effect of double strand break on PTTG1 expression was investigated in OSCC growth. To identify the role of PTTG1 in OSCC growth, the cell viability and senescence was analyzed by EdU and senescence‑associated beta‑galactosidase (SA‑β‑gal) assay, respectively. To verify the DNA damage‑induced senescence of PTTG1, the chromosomal damage in OSCC was analyzed in vitro. Finally, the effect of PTTG1 on tumor growth and gene expression related to cell viability and DNA damaged‑induced senescence was investigated in vivo. PTTG1 expression was compared between OSCC and healthy patient samples (n=32) using reverse transcription‑quantitative PCR and immunohistochemistry; and it was found that PTTG1 expression was upregulated in OSCC. Small interfering RNA‑mediated knockdown of PTTG1 in two OSCC cell lines revealed that PTTG1 downregulation significantly inhibited cell proliferation and arrested the cell cycle pathway as evidenced by changes in checkpoint genes (such as cyclin D1, E and B1). PTTG1 knockdown also increased apoptosis, as evidenced by the upregulation of apoptotic genes [such as cleaved (c‑) Caspase‑7 and c‑poly (ADP‑ribose) polymerase]. Moreover, PTTG1 downregulation promoted cellular senescence, as shown by western blotting and SA‑β‑gal staining. Finally, senescence‑induced DNA damage was observed in OSCC cells, which accelerates genomic instability, through chromosomal damage analysis. Taken together, the present findings suggested that PTTG1 acts as a proto‑oncogene; regulates cell proliferation, cell cycle, cellular senescence and DNA damage in OSCC; and may serve as a novel diagnostic biomarker and potential therapeutic target for OSCC.

Multi-Omics Analysis of the Oncogenic Value of Pituitary Tumor-Transforming Gene 1 (PTTG1) in Human Cancers.

The pituitary tumor-transforming gene 1 (PTTG1), also recognized as securin, plays a crucial role in diverse biological processes, such as restraining sister chromatid segregation, facilitating DNA repair, contributing to organ development, and governing angiogenesis. Additionally, it regulates the expression and secretion of transfer factors. The epigenetic characteristics of PTTG1 suggest its potential in elucidating the progression of malignant tumors in pan-cancer. Nevertheless, the current comprehension of this relationship remains limited, necessitating further comprehensive studies to delve into the underlying pathogenesis. This investigation aimed to explore the potential functions of PTTG1 in pan-cancer by leveraging existing databases, such as TCGA and GTEx. Notably, PTTG1 was overexpressed in nearly all tumors, indicating promising prognostic and diagnostic capabilities. Moreover, the observed correlation between PTTG1 and immune cell infiltration, immune checkpoint genes, tumor mutational burden (TMB), microsatellite instability (MSI), and other immune features suggests its potential utility as a guide for immunotherapy. The study unveils that the downregulation of PTTG1 expression in neuroblastoma results in reduced cell proliferation and increased apoptosis, substantiating the proposition that PTTG1 could serve as both a prognostic biomarker and a potential target for immunotherapy across various cancer types. This study centers on the exploration of the expression and role of PTTG1 in both tumors and the tumor microenvironment (TME), offering valuable insights for the development of cancer therapeutic strategies. These discoveries present potential alternative avenues for addressing clinically resistant cancers.

PTTG1 induces pancreatic cancer cell proliferation and promotes aerobic glycolysis by regulating c-myc.

This study aimed to clarify the role of pituitary tumor-transforming gene 1 (PTTG1) in proliferation, migration, invasion, and aerobic glycolysis of pancreatic cancer cells, and evaluate the potential of PTTG1 as a therapeutic target. PTTG1 expression in pancreatic cancers was analyzed using the GEPIA databank. In the Panc1 cell with the PTTG1 knockdown or Mia-PaCa2 cells with PTTG1 overexpression, the cell proliferation was evaluated using cell viability curves and colony formation, and wound heal assay and transwell assay were performed to evaluate the migration and invasion, respectively. Furthermore, a western blot was performed to evaluate the expressions of PTTG1, proliferating cell nuclear antigen, E-cadherin, N-cadherin, and c-myc. Meanwhile, the glucose uptake, extracellular acidification rates (ECAR), and oxygen consumption rates (OCR) were analyzed. Our results showed that PTTG1 expression is upregulated in pancreatic cancer, which promoted cell proliferation. Low PTTG1 contributed to higher disease-free survival and overall survival. In Panc1 cell, PTTG1 knockdown resulted in reduced cell viability and colony formation. The migration and invasion abilities of the cells were also reduced in Panc1 with PTTG1 knockdown. Correspondingly, PTTG1 knockdown decreased c-myc expression, glucose uptake, ECAR, and OCR in Panc1 cells. In Mia-PaCa2 cells, PTTG1 overexpression promoted cell proliferation, aerobic glycolysis, and translocation of β-catenin to the nucleus by regulating c-myc. In conclusion, PTTG1 induces proliferation, migration, and invasion, and promotes aerobic glycolysis in pancreatic cancer cells via regulating c-myc, demonstrating the potential of PTTG1 as a therapeutic target.

Upregulated expression of PTTG1 is associated with progression of pancreatic cancer.

Pancreatic cancer (PC) is an aggressive disease with a very poor prognosis. The insidious onset, rapid progression, and resistance to conventional therapies mark the imperious need for novel biomarkers and therapeutic targets. The pituitary tumor transforming gene 1 (PTTG1), implicated in tumorigenesis and cellular transformation, has been studied in various cancers, however, its role and mechanisms in PC remain to be elucidated for better understanding the disease pathology and in enhancing patient management strategies. The present study examined the PTTG1 messenger RNA (mRNA) expression levels and clinical significance through meta-analysis based on The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Immunohistochemistry (IHC) was used to measure PTTG1 protein levels in PC and adjacent non-cancerous tissues. A correlation was observed between PTTG1 expression and some clinical characteristics based on the TCGA and IHC data. Univariate and multivariate Cox regressions were used to identify independent prognostic factors. Kaplan-Meier (KM) survival analysis was performed. The co-expressed genes of PTTG1 were determined by integrating online tools, and the enrichment analyses were performed to determine PTTG1-related pathways and hub co-expressed genes. PTTG1 was highly expressed in PC tissues based on the TCGA, GEO, and IHC data. The combined standard mean difference (SMD) values of PTTG1 expression based on TCGA and GEO databases was 1.02 [95% confidence interval (CI): 0.74-1.30]. The area under the curve (AUC) based on the summary receiver operating characteristic (sROC) curve was 0.93 (95% CI: 0.90-0.95). PTTG1 overexpression was remarkably correlated with an inferior overall survival (OS). A total of 367 genes were identified as co-expressed genes of PTTG1 in PC and were mainly involved in the cell cycle pathway. The four identified core genes were CDK1, CCNA2, CDC20, and MAD2L1. The upregulated expression of PTTG1 plays an essential role in PC's progression as a biomarker.

MiR-362-3p inhibited the invasion and metastasis of oral squamous cell carcinoma cells by targeting the regulation of pituitary tumor-transforming gene 1.

This study aimed to explore the effect of pituitary tumor-transforming gene 1 (PTT-G1) on the invasion and proliferation of oral squamous cell carcinoma (OSCC) cell lines under the action of miR-362-3p. The bioinformatics online database was used to query the expression of PTTG1 in head and neck squamous cell carcinoma (HNSCC). The expression of PTTG1 in the Cal-27, HN-30, and HOK cell lines was detected by Western blot. A wound-healing assay was used to determine the effect of PTTG1 on the migration ability of the OSCC cells. The Transwell assay was used to examine the changes in cell-invasion ability. 5-ethynyl-2'-deoxyuridine (EdU) cell-proliferation assay was used to detect changes in cell-proliferation ability. Bioinformatics approach predicted the upstream miRNA of PTTG1. The targeting relationship between miR-362-3p and PTTG1 was examined by the dual luciferase assay, and quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the expression of miRNA in OSCC tissues. The ENCORI database showed that PTTG1 expression was up-regulated in OSCC tissues. Western blot confirmed that PTTG1 expression was up-regulated in Cal-27 and HN-30 cells than HOK cells. PTTG1 knockout can inhibit the migration, invasion, and proliferation of Cal-27 and HN-30 cells (P<0.05). Bioinformatics prediction websites predicted that the upstream miRNA of PTTG1 was miR-362-3p, and PTTG1 can bind to miR-362-3p. Results of qRT-PCR showed that miR-362-3p expression was downregulated in OSCC tissues compared with normal tissue (P<0.05). Transwell and EdU experiments confirmed that miR-362-3p knockdown can promote the invasion and proliferation of Cal-27 and HN-30 after PTTG1 knockdown. miR-362-3p can inhibit the invasion and proliferation of Cal-27 and HN-30 cells by targeting PTTG1.

Cleavage efficiency of the intramembrane protease γ-secretase is reduced by the palmitoylation of a substrate's transmembrane domain.

The intramembrane protease γ-secretase has broad physiological functions, but also contributes to Notch-dependent tumors and Alzheimer's disease. While γ-secretase cleaves numerous membrane proteins, only few nonsubstrates are known. Thus, a fundamental open question is how γ-secretase distinguishes substrates from nonsubstrates and whether sequence-based features or post-translational modifications of membrane proteins contribute to substrate recognition. Using mass spectrometry-based proteomics, we identified several type I membrane proteins with short ectodomains that were inefficiently or not cleaved by γ-secretase, including 'pituitary tumor-transforming gene 1-interacting protein' (PTTG1IP). To analyze the mechanism preventing cleavage of these putative nonsubstrates, we used the validated substrate FN14 as a backbone and replaced its transmembrane domain (TMD), where γ-cleavage occurs, with the one of nonsubstrates. Surprisingly, some nonsubstrate TMDs were efficiently cleaved in the FN14 backbone, demonstrating that a cleavable TMD is necessary, but not sufficient for cleavage by γ-secretase. Cleavage efficiencies varied by up to 200-fold. Other TMDs, including that of PTTG1IP, were still barely cleaved within the FN14 backbone. Pharmacological and mutational experiments revealed that the PTTG1IP TMD is palmitoylated, which prevented cleavage by γ-secretase. We conclude that the TMD sequence of a membrane protein and its palmitoylation can be key factors determining substrate recognition and cleavage efficiency by γ-secretase.

IFIH1-mediated post-transcriptional regulation of PTTG1 promotes proliferation and affects PHA-848125 sensitivity and prognosis in oropharyngeal carcinoma.

The pituitary tumor-transforming gene 1 (PTTG1) is an oncogene involved in chromosomal segregation, DNA repair, apoptosis, and metabolism. PTTG1 can be used for clinical diagnosis and treatment and is a potential target for oropharyngeal carcinoma. The proliferation and viability of Cal27 and FaDu cells were assessed using the CCK-8 assay. Real-time PCR and western blotting, respectively, were used to analyze the mRNA and protein expression levels of PTTG1 and IFIH1. The interaction between PTTG1 mRNA and the translational regulatory protein IFIH1 was analyzed using RNA pull-down, RNA immunoprecipitation, and luciferase reporter assays. PTTG1 protein was significantly overexpressed in oropharyngeal carcinoma, whereas PTTG1 mRNA was not. We hypothesized that a translation regulatory protein plays a post-transcriptional role in PTTG1. The IFIH1 protein specifically bound to the 42-52 nt region of PTTG1 mRNA, promoted the translation of PTTG1, and promoted the proliferation of oropharyngeal cancer cells. Administration of the PTTG1 inhibitor PHA-848125 and silencing of IFIH1 synergistically decreased the expression of PTTG1, inhibited the proliferation of oropharyngeal cancer cells, and indicated a good prognosis. We found that the IFIH1-PTTG1 axis could regulate the PHA-848125 response and functionally mediate inter-individual oropharyngeal cancer susceptibility and prognosis. This study aimed to confirm the upstream regulatory genes of PTTG1 and further investigate the specific interactions in this signaling pathway, which will provide a new approach for the treatment of oropharyngeal carcinoma.

A comprehensive characterisation of phaeochromocytoma and paraganglioma tumours through histone protein profiling, DNA methylation and transcriptomic analysis genome wide

BackgroundPhaeochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumours. Pathogenic variants have been identified in more than 15 susceptibility genes; associated tumours are grouped into three Clusters, reinforced by their transcriptional profiles. Cluster 1A PPGLs have pathogenic variants affecting enzymes of the tricarboxylic acid cycle, including succinate dehydrogenase. Within inherited PPGLs, these are the most common. PPGL tumours are known to undergo epigenetic reprograming, and here, we report on global histone post-translational modifications and DNA methylation levels, alongside clinical phenotypes.ResultsOut of the 25 histone post-translational modifications examined, Cluster 1A PPGLs were distinguished from other tumours by a decrease in hyper-acetylated peptides and an increase in H3K4me2. DNA methylation was compared between tumours from individuals who developed metastatic disease versus those that did not. The majority of differentially methylated sites identified tended to be completely methylated or unmethylated in non-metastatic tumours, with low inter-sample variance. Metastatic tumours by contrast consistently had an intermediate DNA methylation state, including the ephrin receptor EPHA4 and its ligand EFNA3. Gene expression analyses performed to identify genes involved in metastatic tumour behaviour pin-pointed a number of genes previously described as mis-regulated in Cluster 1A tumours, as well as highlighting the tumour suppressor RGS22 and the pituitary tumour-transforming gene PTTG1.ConclusionsCombined transcriptomic and DNA methylation analyses revealed aberrant pathways, including ones that could be implicated in metastatic phenotypes and, for the first time, we report a decrease in hyper-acetylated histone marks in Cluster 1 PPGLs.

SPTBN1 Mediates the Cytoplasmic Constraint of PTTG1, Impairing Its Oncogenic Activity in Human Seminoma.

Seminoma is the most common testicular cancer. Pituitary tumor-transforming gene 1 (PTTG1) is a securin showing oncogenic activity in several tumors. We previously demonstrated that nuclear PTTG1 promotes seminoma tumor invasion through its transcriptional activity on matrix metalloproteinase 2 (MMP-2) and E-cadherin (CDH1). We wondered if specific interactors could affect its subcellular distribution. To this aim, we investigated the PTTG1 interactome in seminoma cell lines showing different PTTG1 nuclear levels correlated with invasive properties. A proteomic approach upon PTTG1 immunoprecipitation uncovered new specific securin interactors. Western blot, confocal microscopy, cytoplasmic/nuclear fractionation, sphere-forming assay, and Atlas database interrogation were performed to validate the proteomic results and to investigate the interplay between PTTG1 and newly uncovered partners. We observed that spectrin beta-chain (SPTBN1) and PTTG1 were cofactors, with SPTBN1 anchoring the securin in the cytoplasm. SPTBN1 downregulation determined PTTG1 nuclear translocation, promoting its invasive capability. Moreover, a PTTG1 deletion mutant lacking SPTBN1 binding was strongly localized in the nucleus. The Atlas database revealed that seminomas that contained higher nuclear PTTG1 levels showed significantly lower SPTBN1 levels in comparison to non-seminomas. In human seminoma specimens, we found a strong PTTG1/SPTBN1 colocalization that decreases in areas with nuclear PTTG1 distribution. Overall, these results suggest that SPTBN1, along with PTTG1, is a potential prognostic factor useful in the clinical management of seminoma.

Identification of several inflammation-related genes based on bioinformatics and experiments.

Osteoarthritis (OA) is a common disease of elderly individuals, with an unclear pathogenesis and limited treatment options to date. Inflammation occurs prominently in osteoarthritis, thereby making anti-inflammatory treatments promising in clinical outcomes. Therefore, it is of diagnostic and therapeutic significance to explore more inflammatory genes. In this study, appropriate datasets were first acquired through gene set enrichment analysis (GSEA), followed by inflammation-related genes through weighted gene coexpression network analysis (WGCNA). Two machine learning algorithms (random forest-RF and support vector machine-recursive feature elimination, SVM-RFE) were used to capture the hub genes. In addition, two genes negatively associated with inflammation and osteoarthritis were identified. Afterwards, these genes were verified through experiments and network pharmacology. Due to the association between inflammation and many diseases, the expression levels of the above genes in various inflammatory diseases were determined through literature and experiments. Two hub genes closely related to osteoarthritis and inflammation were obtained, namely, lysyl oxidase-like 1 (LOXL1) and pituitary tumour-transforming gene (PTTG1), which were shown to be highly expressed in osteoarthritis according to the literature and experiments. However, the expression levels of receptor expression-enhancing protein (REEP5) and cell division cycle protein 14B (CDC14B) remained unchanged in osteoarthritis. This finding was consistent with our verification from the literature and experiments that some genes were highly expressed in numerous inflammation-related diseases, while REEP5 and CDC14B were almost unchanged. Meanwhile, taking PTTG1 as an example, we found that inhibition of PTTG1 expression could suppress the expression of inflammatory factors and protect the extracellular matrix through the microtubule-associated protein kinase (MAPK) signalling pathway. LOXL1 and PTTG1 were highly expressed in some inflammation-related diseases, while that of REEP5 and CDC14B were almost unchanged. PTTG1 may be a potential target for the treatment of osteoarthritis.

Phosphorylated PTTG1 switches its subcellular distribution and promotes β-catenin stabilization and subsequent transcription activity.

The Wnt/β-catenin signaling is usually abnormally activated in hepatocellular carcinoma (HCC), and pituitary tumor-transforming gene 1 (PTTG1) has been found to be highly expressed in HCC. However, the specific mechanism of PTTG1 pathogenesis remains poorly understood. Here, we found that PTTG1 is a bona fide β-catenin binding protein. PTTG1 positively regulates Wnt/β-catenin signaling by inhibiting the destruction complex assembly, promoting β-catenin stabilization and subsequent nuclear localization. Moreover, the subcellular distribution of PTTG1 was regulated by its phosphorylation status. Among them, PP2A induced PTTG1 dephosphorylation at Ser165/171 residues and prevented PTTG1 translocation into the nucleus, but these effects were effectively reversed by PP2A inhibitor okadaic acid (OA). Interestingly, we found that PTTG1 decreased Ser9 phosphorylation-inactivation of GSK3β by competitively binding to PP2A with GSK3β, indirectly leading to cytoplasmic β-catenin stabilization. Finally, PTTG1 was highly expressed in HCC and associated with poor patient prognosis. PTTG1 could promote the proliferative and metastasis of HCC cells. Overall, our results indicated that PTTG1 plays a crucial role in stabilizing β-catenin and facilitating its nuclear accumulation, leading to aberrant activation of Wnt/β-catenin signaling and providing a feasible therapeutic target for human HCC.

PTTG1 Enhances Oncolytic Adenovirus 5 Entry into Pancreatic Adenocarcinoma Cells by Increasing CXADR Expression.

Pituitary tumor-transforming gene 1 (PTTG1) is overexpressed in various types of tumors and functions as an oncogene; it could also be a potential target in tumor therapy. Meanwhile, the high mortality of pancreatic adenocarcinoma (PAAD) largely depends on the limited effectiveness of therapy. Based on the promising potential of PTTG1 in cancer treatment, we explored the influence of PTTG1 on the treatment of PAAD in this study. The Cancer Genome Atlas Program (TCGA) data showed that higher expression of PTTG1 was associated with higher clinical stages and worse prognosis of pancreatic cancer. In addition, the CCK-8 assay showed that the IC50 of gemcitabine and 5-fluorouracil (5-FU) was increased in BxPC-3-PTTG1high and MIA PaCa-2-PTTG1high cells. The TIDE algorithm indicated that the immune checkpoint blockades' (ICBs) efficiency is poor in the PTTG1 high group. Furthermore, we found that the efficiency of OAd5 was enhanced in BxPC-3-PTTG1high and MIA PaCa-2-PTTG1high cells and poor in BxPC-3-PTTG1low and MIA PaCa-2-PTTG1low cells. We used the OAd5 expressing GFP for transduction. As a result, the fluorescence intensity was enhanced in BxPC-3-PTTG1high and MIA PaCa-2-PTTG1high cells and decreased in BxPC-3-PTTG1low and MIA PaCa-2-PTTG1low cells 24 h after OAd5 transduction. The fluorescence intensity indicated that PTTG1 increased OAd5 entry. The flow cytometry assay showed that OAd5 receptor CXADR expression was enhanced by PTTG1. PTTG1 failed to further enhance OAd5 transduction in the case of CXADR knockdown. In summary, PTTG1 enhanced OAd5 transduction into pancreatic cancer cells by increasing CXADR expression on the cell surface.

Abstract 3616: Investigating proto-oncogene PBF-induced cell migration and invasion

Abstract The proto-oncogene pituitary tumor transforming gene binding factor (PTTG1IP/PBF) is overexpressed in multiple tumors and associated with tumor progression. PBF mediates several tumorigenic processes, including cell motility, whereby it potently induces cancer cell migration and invasion. PBF is phosphorylated by Src kinase at Y174 and mutation of this residue (Y174A) renders PBF unable to induce cell invasion, suggesting that phosphorylation mediates the stimulation of cancer cell motility by PBF. This study aimed to further elucidate the mechanism of PBF-induced cell motility. PBF-Y174 is also the key residue in a YXXΦ endocytosis motif. Both PBF phosphorylation and endocytosis were found to be essential for PBF-induced cell motility as mutants which disrupted either process were unable to stimulate thyroid and breast cancer cell migration and invasion. To elucidate molecular events downstream of PBF overexpression, phosphoproteomic and RNA-Seq analyses of normal thyroid cells (Nthy-ori 3-1) with stable PBF overexpression were performed and showed an enrichment in molecules involved in cell adhesion and cytoskeleton organisation. These findings prompted further investigation into a physiological role for PBF in cell motility. We utilised a novel Pbf knockout (Pbf−/−) mouse model generated through CRISPR/Cas9-mediated deletion of Pbf exon 4 in C57BL/6N mice to determine the impact of Pbf deletion on cellular mechanisms. Mouse embryonic fibroblasts (MEFs) were isolated at embryonic day 13.5 and used as primary cultures. Pbf−/- MEFs showed a significant reduction in migration and invasion compared with wild-type (Pbf+/+) MEFs. Interestingly, the loss of one functional copy of Pbf in heterozygote MEFs (Pbf+/−) resulted in an intermediate decrease in motility suggesting a gene-dosage effect. Initial immunofluorescent studies of Pbf−/− MEFs suggest alterations in focal adhesions (FAs). In Pbf+/+ MEFs focal adhesion kinase (FAK) and paxillin staining highlighted FA structures that were normally elongated and aligned with actin stress fibers. In contrast, Pbf−/- MEFs demonstrated a significant reduction in FAK and paxillin staining with smaller, punctate and more radially distributed FAs. These studies demonstrate a physiological role for PBF in cell adhesion and migration and further elucidate the mechanism by which PBF induces cell motility in tumor progression. Citation Format: Merve Kocbiyik, Selvambigai Manivannan, Ling Zha, Katie Brookes, Martin L Read, Chris J McCabe, Vicki E Smith. Investigating proto-oncogene PBF-induced cell migration and invasion. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3616.

PTTG1 promotes CD34+CD45+ cells to repair the pulmonary vascular barrier via activating the VEGF-bFGF/PI3K/AKT/eNOS signaling pathway in rats with phosgene-induced acute lung injury

Accidental exposure to phosgene can cause acute lung injury (ALI), characterized by uncontrolled inflammation and impaired lung blood-gas barrier. CD34+CD45+ cells with high pituitary tumor transforming gene 1 (PTTG1) expression were identified around rat pulmonary vessels through single-cell RNA sequencing, and have been shown to attenuate P-ALI by promoting lung vascular barrier repair. As a transcription factor closely related to angiogenesis, whether PTTG1 plays a role in CD34+CD45+ cell repairing the pulmonary vascular barrier in rats with P-ALI remains unclear. This study provided compelling evidence that CD34+CD45+ cells possess endothelial differentiation potential. Rats with P-ALI were intratracheally administered with CD34+CD45+ cells transfected with or without PTTG1-overexpressing and sh-PTTG1 lentivirus. It was found that CD34+CD45+ cells reduced the pulmonary vascular permeability and mitigated the lung inflammation, which could be reversed by knocking down PTTG1. Although PTTG1 overexpression enhanced the ability of CD34+CD45+ cells to attenuate P-ALI, no significant difference was found. PTTG1 was found to regulate the endothelial differentiation of CD34+CD45+ cells. In addition, knocking down of PTTG1 significantly reduced the protein levels of VEGF and bFGF, as well as their receptors, which in turn inhibited the activation of the PI3K/AKT/eNOS signaling pathway in CD34+CD45+ cells. Moreover, LY294002 (PI3K inhibitor) treatment inhibited the endothelial differentiation of CD34+CD45+ cells, while SC79 (AKT activator) yielded the opposite effect. These findings suggest that PTTG1 can promote the endothelial differentiation of CD34+CD45+ cells by activating the VEGF-bFGF/PI3K/AKT/eNOS signaling pathway, leading to the repair of the pulmonary vascular barrier in rats with P-ALI.

PTTG1 alleviates acute alcoholic liver injury by inhibiting endoplasmic reticulum stress-induced hepatocyte pyroptosis.

Heavy drinking is a primary cause of alcoholic liver injury (ALI). Pituitary tumour transforming gene 1 (PTTG1) is involved in the occurrence and development of hepatocellular carcinoma (HCC), which is a well-known inflammation-related cancer with various aetiologies, including alcohol consumption. However, the role of PTTG1 in alcohol-induced liver injury and inflammation is not clear. Blood samples were collected from patients with acute alcohol intoxication (n=20) and healthy controls (n=20). PTTG1 knockout (KO) mice and PTTG1 transgenic (TG) mice were given a single gavage of alcohol (5g/kg, 50%) to construct the alcohol-induced liver injury. We found that serum PTTG1 levels were downregulated in acute ALI patients. In addition, acute alcohol administration significantly reduced PTTG1 levels in the serum and liver of mice. Compared to wild-type mice, PTTG1 KO mice had more serious liver injury, which was accompanied by worsened hepatic endoplasmic reticulum (ER) stress and hepatocyte pyroptosis induced by alcohol. Similarly, PTTG1 deficiency exacerbated alcohol-induced cell death in primary mouse hepatocytes and LO2 cells, by increasing hepatic ER stress and pyroptosis. Importantly, TUDCA, an ER stress inhibitor, could blocked alcohol-induced hepatic pyroptosis in PTTG1 knockdown LO2 cells. Finally, overexpression of PTTG1 substantially attenuated alcohol-induced liver injury by reducing ER stress and hepatic pyroptosis in mice. We demonstrated that PTTG1 participates in ALI and has a protective effect against alcohol-induced hepatic ER stress and pyroptosis.

Prognostic Biomarkers in Pituitary Tumours: A Systematic Review.

Pituitary tumours (PTs) are the second most common intracranial tumour. Although the majority show benign behaviour, they may exert aggressive behaviour and can be resistant to treatment. The aim of this review is to report the recently identified biomarkers that might have possible prognostic value. Studies evaluating potentially prognostic biomarkers or a therapeutic target in invasive/recurrent PTs compared with either non-invasive or non-recurrent PTs or normal pituitaries are included in this review. In the 28 included studies, more than 911 PTs were evaluated. A systematic search identified the expression of a number of biomarkers that may be positively correlated with disease recurrence or invasion in PT, grouped according to role: (1) insensitivity to anti-growth signals: minichromosome maintenance protein 7; (2) evasion of the immune system: cyclooxygenase 2, arginase 1, programmed cell death protein 1 (PD-1)/programmed death ligand 2, cluster of differentiation (CD) 80/CD86; (3) sustained angiogenesis: endothelial cell-specific molecule, fibroblast growth factor receptor, matrix metalloproteinase 9, pituitary tumour transforming gene; (4) self-sufficiency in growth signals: epidermal growth factor receptor; and (5) tissue invasion: matrix metalloproteinase 9, fascin protein. Biomarkers with a negative correlation with disease recurrence or invasion include: (1) insensitivity to anti-growth signals: transforming growth factor β1, Smad proteins; (2) sustained angiogenesis: tissue inhibitor of metalloproteinase 1; (3) tissue invasion: Wnt inhibitory factor 1; and (4) miscellaneous: co-expression of glial fibrillary acidic protein and cytokeratin, and oestrogen receptors α36 and α66. PD-1/programmed cell death ligand 1 showed no clear association with invasion or recurrence, while cyclin A, cytotoxic T lymphocyte-associated protein 4, S100 protein, ephrin receptor, galectin-3 , neural cell adhesion molecule, protein tyrosine phosphatase 4A3 and steroidogenic factor 1 had no association with invasion or recurrence of PT. With the aim to develop a more personalized approach to the treatment of PT, and because of the limited number of molecular targets currently studied in the context of recurrent PT and invasion, a better understanding of the most relevant of these biomarkers by well-d esigned interventional studies will lead to a better understanding of the molecular profile of PT. This should also meet the increased need of treatable molecular targets.

Retraction: Correlations of Pituitary Tumor Transforming Gene Expression with Human Pituitary Adenomas: A Meta-Analysis.

Retraction: Correlations of Pituitary Tumor Transforming Gene Expression with Human Pituitary Adenomas: A Meta-Analysis.

Pituitary tumor transforming gene 1 promotes proliferation and malignant phenotype in osteosarcoma via NF-κB signaling

BackgroundPituitary tumor transforming gene (PTTG) is an oncogene reported to be actively promotes tumorigenesis in multiple tumors. Osteosarcoma (OS) is the most common primary osseous sarcoma, however, the functional significance and mechanisms underlying whether and how PTTG1 promotes OS remain largely unknown. MethodsHere, in our study, PTTG1 levels in clinical samples and cell lines were determined by western blotting and immunohistochemistry. The viability and migratory/invasive potential of OS cells were assessed using Cell Counting Kit-8, colony formation, wound healing, and Transwell assays. The effects of PTTG1 on NF-κB signaling pathways were evaluated both in vivo and in vitro. ResultsAn abnormally elevated expression of PTTG1was confirmed in human OS tissues and OS cell lines and PTTG1 levels were positively correlated with OS clinicopathological grade. We further showed that knocking down PTTG1 attenuated the viability and migratory/invasive capacity of OS cells (MG63 and HOS-8603). Additionally, the following key mechanistic principle was revealed: knockdown PTTG1-mediated OS tumorgenesis supression was associated with inactivation of the NF-κB pathway. We confirmed these results by additional nonpharmacological intervention and same conclusions were obtained in the context of opposite functional analyses. Furthermore, we also demonstrated that OS cell lines overexpressed PTTG1 showed increased tumorigenesis in athymic nude mice. ConclusionsTo sum up, the present study suggests that PTTG1 is involved in the enhancement of the malignancy and carcinogenesis of OS by regulating NF-κB signaling. Accordingly, PTTG1 likely functions as an oncogene in OS and may represent a potential therapeutic target for this cancer.

Sp4 Regulates PTTG1IP Gene Transcription and Expression.

Pituitary tumor-transforming gene 1 protein (PTTG)-interacting protein, also known as PTTG-binding factor (PBF), is encoded by a proto-oncogene PTTG1IP. PBF has been identified through its interaction with PTTG. Similar to PTTG, PBF has been implicated in the etiology of several tumors, including pituitary, thyroid, and breast cancer. PBF can induce the translocation of PTTG into the nucleus, and then lead to tumorigenesis. Studies have shown that PBF plays a vital and complex role in increasing tumor development. However, the transcriptional regulation of PTTG1IP gene remains undefined. In this study, we have cloned a 467-bp fragment of the 5' flanking region of the human PTTG1IP gene and identified the region (-212 to +7 bp) necessary for PTTG1IP gene promoter activity by luciferase assay. Electrophoretic mobility shift assay revealed PTTG1IP gene promoter containing Sp4 response elements. Overexpression of Sp4 increased PTTG1IP gene transcription and expression in HeLa cells. Our study demonstrates that Sp4 regulates PTTG1IP gene transcription and expression.

PTTG1/ZEB1 Axis Regulates E-Cadherin Expression in Human Seminoma.

Simple SummarySeminoma represents one of the most common neoplasms in Caucasian males between 15 and 40 years old. The molecular pathways underlying its clinical behavior are far from being understood yet. We previously demonstrated that nuclear Pituitary-tumor transforming-gene 1 (PTTG1), overexpressed in several neoplasms, promotes invasiveness through its transcriptional target matrix-metalloproteinase-2 (MMP2). PTTG1 sustains the migratory and invasive properties of cancer cells through the induction of the epithelial-to-mesenchymal transition (EMT). E-Cadherin (E-CAD) repression is the first step of EMT. Therefore, we investigated the role of PTTG1 in EMT in human seminoma using an in vitro and in vivo model and through Atlas database interrogation. Our data showed a PTTG1-mediated E-CAD transcriptional repression through Zinc finger E-box binding homeobox 1 (ZEB1), a master regulator of the EMT process. Our data provide insights into the molecular characterization of seminoma, promoting PTTG1 as a prognostic marker useful in human seminoma clinical management.(1) Background: PTTG1 sustains the EMT process and the invasiveness of several neoplasms. We previously showed the role of nuclear PTTG1 in promoting invasiveness, through its transcriptional target MMP2, in seminoma in vitro models. Here, we investigated the key players involved in PTTG1-mediated EMT in human seminoma. (2) Methods: Two seminoma cell lines and four human seminoma tumor specimens were used. E-Cadherin gene regulation was investigated using Western blot, real-time PCR, and luciferase assay. Immunoprecipitation, ChIP, RE-ChIP, and confocal microscopy analysis were performed to evaluate the interplay between PTTG1 and ZEB1. Matrigel invasion and spheroid formation assays were applied to functionally investigate PTTG1 involvement in the EMT of seminoma cell lines. RNA depletion and overexpression experiments were performed to verify the role of PTTG1/ZEB1 in E-Cadherin repression and seminoma invasiveness. E-Cadherin and ZEB1 levels were analyzed in human testicular tumors from the Atlas database. (3) Results: PTTG1 transcriptionally represses E-Cadherin in seminoma cell lines through ZEB1. The cooperation of PTTG1 with ZEB1 has a significant impact on cell growth/invasion properties involving the EMT process. Analysis of the Atlas database of testicular tumors showed significantly lower E-Cadherin levels in seminoma, where PTTG1 showed nuclear staining. Finally, PTTG1 and ZEB1 strongly localize together in the periphery of the tumors. (4) Conclusions: These results strengthen the evidence for a role of PTTG1 in the EMT process in human seminomas through its cooperation with the transcriptional repressor ZEB1 on the E-Cadherin gene. Our data enrich the molecular characterization of seminoma, suggesting that PTTG1 is a prognostic factor in seminoma clinical management.