A single mutation in Securin induces chromosomal instability and enhances cell invasion

Exploring the Blood Biomarkers and Potential Therapeutic Agents for Human Acute Mountain Sickness Based on Transcriptomic Analysis, Inflammatory Infiltrates and Molecular Docking

A high-altitude, low-pressure hypoxic environment has severe effects on the health and work efficiency of its residents, and inadequate preventive measures and adaptive training may lead to the occurrence of AMS. Acute exposure to hypoxia conditions can have a less-favorable physiological effect on the human immune system. However, the regulation of the immune system in high-altitude environments is extremely complex and remains elusive. This study integrated system bioinformatics methods to screen for changes in immune cell subtypes and their associated targets. It also sought potential therapeutically effective natural compound candidates. The present study observed that monocytes, M1 macrophages and NK cells play a crucial role in the inflammatory response in AMS. IL15RA, CD5, TNFSF13B, IL21R, JAK2 and CXCR3 were identified as hub genes, and JAK2 was positively correlated with monocytes; TNFSF13B was positively correlated with NK cells. The natural compound monomers of jasminoidin and isoliquiritigenin exhibited good binding affinity with JAK2, while dicumarol and artemotil exhibited good binding affinity with TNFSF13B, and all are expected to become a potential therapeutic agents.

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.

Role of Moonlighting Proteins in Disease: Analyzing the Contribution of Canonical and Moonlighting Functions in Disease Progression

The term moonlighting proteins refers to those proteins that present alternative functions performed by a single polypeptide chain acquired throughout evolution (called canonical and moonlighting, respectively). Over 78% of moonlighting proteins are involved in human diseases, 48% are targeted by current drugs, and over 25% of them are involved in the virulence of pathogenic microorganisms. These facts encouraged us to study the link between the functions of moonlighting proteins and disease. We found a large number of moonlighting functions activated by pathological conditions that are highly involved in disease development and progression. The factors that activate some moonlighting functions take place only in pathological conditions, such as specific cellular translocations or changes in protein structure. Some moonlighting functions are involved in disease promotion while others are involved in curbing it. The disease-impairing moonlighting functions attempt to restore the homeostasis, or to reduce the damage linked to the imbalance caused by the disease. The disease-promoting moonlighting functions primarily involve the immune system, mesenchyme cross-talk, or excessive tissue proliferation. We often find moonlighting functions linked to the canonical function in a pathological context. Moonlighting functions are especially coordinated in inflammation and cancer. Wound healing and epithelial to mesenchymal transition are very representative. They involve multiple moonlighting proteins with a different role in each phase of the process, contributing to the current-phase phenotype or promoting a phase switch, mitigating the damage or intensifying the remodeling. All of this implies a new level of complexity in the study of pathology genesis, progression, and treatment. The specific protein function involved in a patient's progress or that is affected by a drug must be elucidated for the correct treatment of diseases.

Methylglyoxal Impairs Sister Chromatid Separation in Lymphocytes

The accurate segregation of sister chromatids is complex, and errors that arise throughout this process can drive chromosomal instability and tumorigenesis. We recently showed that methylglyoxal (MGO), a glycolytic by-product, can cause chromosome missegregation events in lymphocytes. However, the underlying mechanisms of this were not explored. Therefore, in this study, we utilised shotgun proteomics to identify MGO-modified proteins, and label-free quantitation to measure changes in protein abundance following exposure to MGO. We identified numerous mitotic proteins that were modified by MGO, including those involved in the separation and cohesion of sister chromatids. Furthermore, the protein abundance of Securin, an inhibitor of sister chromatid separation, was increased following treatment with MGO. Cytological examination of chromosome spreads showed MGO prevented sister chromatid separation, which was associated with the formation of complex nuclear anomalies. Therefore, results from this study suggest MGO may drive chromosomal instability by preventing sister chromatid separation.

Nuclear Localization of PTTG1 Promotes Migration and Invasion of Seminoma Tumor through Activation of MMP-2

Simple Summary

Seminoma is the most common subtype of testicular germ cell tumors (TGCTs) and its molecular patterns have not been clarified. The pituitary tumor-transforming gene 1 (PTTG1) is a securin and its overexpression is reported in many cancers. We previously demonstrated that PTTG1 is mainly localized at the neoplasm periphery and infiltration area of seminoma. Therefore, we aim to investigate in vitro the role of PTTG1 on the invasive properties of seminoma. Our results elucidate the role of nuclear PTTG1 in promoting invasiveness and the metastatic process of these cells through its transcriptional target matrix-metalloproteinase-2 (MMP-2). Analysis of human testicular tumors from the Atlas database revealed an exclusive PTTG1 nuclear localization and a concomitant increase of MMP-2 levels in seminoma compared to non-seminoma tumors. Our data provide insights into the molecular characterization of seminoma, promoting PTTG1 as a prognostic marker useful in human seminoma clinical management.

Abstract

(1) Background: PTTG1 sustains the invasiveness of several cancer types. We previously reported that in seminomas, PTTG1 was detected in the peripheral area of the tumor and in the leading infiltrative edge. Here, we investigate the PTTG1 role on the invasive properties of seminoma. (2) Methods: three seminoma cell lines were used as in vitro model. PTTG1 levels and localization were investigated by biochemical and immunofluorescence analyses. Wound-healing, Matrigel invasion assays, and zymography were applied to study migratory and invasive capability of the cell lines. RNA interference and overexpression experiments were performed to address the PTTG1 role in seminoma invasiveness. PTTG1 and its target MMP-2 were analyzed in human testicular tumors using the Atlas database. (3) Results: PTTG1 was highly and differentially expressed in the seminoma cell lines. Nuclear PTTG1 was positively correlated to the aggressive phenotype. Its modulation confirms these results. Atlas database analysis revealed that PTTG1 was localized in the nucleus in seminoma compared with non-seminoma tumors, and that MMP-2 levels were significantly higher in seminomas. (4) Conclusions: nuclear PTTG1 promotes invasiveness of seminoma cell lines. Atlas database supported these results. These data lead to the hypothesis that nuclear PTTG1 is an eligible prognostic factor in seminomas.

The role of Anaphase Promoting Complex activation, inhibition and substrates in cancer development and progression

The Anaphase Promoting Complex (APC), a multi-subunit ubiquitin ligase, facilitates mitotic and G1 progression, and is now recognized to play a role in maintaining genomic stability. Many APC substrates have been observed overexpressed in multiple cancer types, such as CDC20, the Aurora A and B kinases, and Forkhead box M1 (FOXM1), suggesting APC activity is important for cell health. We performed BioGRID analyses of the APC coactivators CDC20 and CDH1, which revealed that at least 69 proteins serve as APC substrates, with 60 of them identified as playing a role in tumor promotion and 9 involved in tumor suppression. While these substrates and their association with malignancies have been studied in isolation, the possibility exists that generalized APC dysfunction could result in the inappropriate stabilization of multiple APC targets, thereby changing tumor behavior and treatment responsiveness. It is also possible that the APC itself plays a crucial role in tumorigenesis through its regulation of mitotic progression. In this review the connections between APC activity and dysregulation will be discussed with regards to cell cycle dysfunction and chromosome instability in cancer, along with the individual roles that the accumulation of various APC substrates may play in cancer progression.

PTTG and PBF Functionally Interact with p53 and Predict Overall Survival in Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) is the 6th most common cancer worldwide and poses a significant health burden due to its rising incidence. Although the proto-oncogene pituitary tumor-transforming gene 1 (PTTG) predicts poor patient outcome, its mechanisms of action are incompletely understood. We show here that the protein PBF modulates PTTG function, is overexpressed in HNSCC tumors, and correlates with significantly reduced survival. Lentiviral shRNA attenuation of PTTG or PBF expression in HNSCC cells with either wild-type or mutant p53, and with and without HPV infection, led to dysregulated expression of p53 target genes involved in DNA repair and apoptosis. Mechanistically, PTTG and PBF affected each other's interaction with p53 and cooperated to reduce p53 protein stability in HNSCC cells independently of HPV. Depletion of either PTTG or PBF significantly repressed cellular migration and invasion and impaired colony formation in HNSCC cells, implicating both proto-oncogenes in basic mechanisms of tumorigenesis. Patients with HNSCC with high tumoral PBF and PTTG had the poorest overall survival, which reflects a marked impairment of p53-dependent signaling.Significance: These findings reveal a complex and novel interrelationship between the expression and function of PTTG, PBF, and p53 in human HNSCC that significantly influences patient outcome. Cancer Res; 78(20); 5863-76. ©2018 AACR.

Integrated analysis highlights APC11 protein expression as a likely new independent predictive marker for colorectal cancer

After a diagnosis of colorectal cancer (CRC), approximately 50% of patients will present distant metastasis. Although significant progress has been made in treatments, most of them will die from the disease. We investigated the predictive and prognostic potential of APC11, the catalytic subunit of APC/C, which has never been examined in the context of CRC. The expression of APC11 was assessed in CRC cell lines, in tissue microarrays (TMAs) and in public datasets. Overexpression of APC11 mRNA was associated with chromosomal instability, lymphovascular invasion and residual tumor. Regression models accounting for the effects of well-known protein markers highlighted association of APC11 protein expression with residual tumor (odds ratio: OR = 6.51; 95% confidence intervals: CI = 1.54–27.59; P = 0.012) and metastasis at diagnosis (OR = 3.87; 95% CI = 1.20–2.45; P = 0.024). Overexpression of APC11 protein was also associated with worse distant relapse-free survival (hazard ratio: HR = 2.60; 95% CI = 1.26–5.37; P = 0.01) and worse overall survival (HR = 2.69; 95% CI = 1.31–5.51; P = 0.007). APC11 overexpression in primary CRC thus represents a potentially novel theranostic marker of metastatic CRC.

Overexpression of ubiquitin specific proteases 44 promotes the malignancy of glioma by stabilizing tumor-promoter securin

Ubiquitin specific peptidase 44 (USP44) has been identified as an important component of spindle assemble checkpoint (SAC) to prevent the formation of aneuploidy. However, recent study raised a controversy about the effect of USP44 in tumor. Here, we first confirmed the intranuclear localization of USP44 by testing several specific antibodies to recognize endogenous USP44. Then, data from IHC and qRT-PCR assay indicated that the high expression of USP44 existed in high-grade glioma tissues and signified a poor prognosis. Knockdown of USP44 inhibited proliferation, migration and invasion, induced apoptosis, and arrested cell cycle in G2/M phase in the established glioma cell lines. Down-regulation of oncoprotein securin was detected in USP44 deficient cells, and the interaction of endogenous USP44 and securin was confirmed by immunoprecipitation in U251MG cells, which indicated that securin was a substrate of USP44, and might be stabilized by USP44. In vivo, knockdown of USP44 inhibited the tumorigenicity of U87MG cells significantly. Consequently, our findings suggested that overexpression of USP44 could enhance the malignancy of glioma via securin. USP44 might serve as a predictive biomarker, and the USP44-securin pathway might provide a new therapeutic strategy for the treatment of glioma.

Separase: Function Beyond Cohesion Cleavage and an Emerging Oncogene

Proper and timely segregation of genetic endowment is necessary for survival and perpetuation of every species. Mis-segregation of chromosomes and resulting aneuploidy leads to genetic instability, which can jeopardize the survival of an individual or population as a whole. Abnormality with segregation of genetic contents has been associated with several medical consequences including cancer, sterility, mental retardation, spontaneous abortion, miscarriages, and other birth related defects. Separase, by irreversible cleavage of cohesin complex subunit, paves the way for metaphase/anaphase transition during the cell cycle. Both over or reduced expression and altered level of separase have been associated with several medical consequences including cancer, as a result separase now emerges as an important oncogene and potential molecular target for medical intervenes. Recently, separase is also found to be essential in separation and duplication of centrioles. Here, I review the role of separase in mitosis, meiosis, non-canonical roles of separase, separase regulation, as a regulator of centriole disengagement, nonproteolytic roles, diverse substrates, structural insights, and association of separase with cancer. At the ends, I proposed a model which showed that separase is active throughout the cell cycle and there is a mere increase in separase activity during metaphase contrary to the common believes that separase is inactive throughout cell cycle except for metaphase. J. Cell. Biochem. 118: 1283-1299, 2017. © 2016 Wiley Periodicals, Inc.

Inhibition of PTTG1 expression by microRNA suppresses proliferation and induces apoptosis of malignant glioma cells

The present study aimed to investigate the role of pituitary tumor-transforming gene 1 (PTTG1) in the proliferation, invasion and apoptosis of human malignant glioma U251 cells. Firstly, 2 microRNAs (miRNAs) targeting PTTG1 messenger (m)RNA were ligated into a pcDNA6.2-GW/EmGFP-miR expression vector. The recombinant plasmids, miRNA-1 and miRNA-2 (miR-2), were transfected into U251 cells using the liposome method. PTTG1 mRNA and protein levels were evaluated using quantitative polymerase chain reaction and western blot analysis. The proliferation and invasion abilities of U251 cells were determined using methylthiazol tetrazolium and Matrigel assays. Flow cytometry analysis with Annexin V/propidium iodide double staining was used to determine the percentage of apoptotic cells. PTTG1 expression was effectively suppressed by miR-2. U251 cell growth was inhibited between 10.7 and 34.7% in the miR-2 group compared with the blank group. The Matrigel assay demonstrated that the percentage of infiltrating U251 cells was significantly lower in the miR-2 group (12.3±1.0%) compared to the blank group (24.7±1.4%; P<0.001) and the negative control group (24.0±2.0%; P<0.05). A higher percentage of apoptotic U251 cells were observed in the miR-2 group compared with the blank group (53.6 vs. 32.4%) using flow cytometry due to cycle arrests at the G2/M phase. The miR-2-transfected U251 cells were subcutaneously injected into nude mice, and these mice possessed a decreased tumor tissue growth rate and higher percentage of apoptotic cells compared with the blank and negative control groups. In conclusion, PTTG1 gene expression in human malignant glioma U251 cells was effectively suppressed by exogenous miR-2. The downregulation of PTTG1 induced glioma cell apoptosis and cell cycle arrest at the G2/M phase, which inhibited cell proliferation, reverse invasion and infiltration of glioma cells.

Genetic variation in the major mitotic checkpoint genes associated with chromosomal aberrations in healthy humans

Non-specific chromosomal aberrations (CAs) are microscopically detected in about 1% of lymphocytes drawn from healthy persons. Causes of CAs in general population are not known but they may be related to risk of cancer. In view of the importance of the mitotic checkpoint machinery on maintaining chromosomal integrity we selected 9 variants in main checkpoint related genes (BUB1B, BUB3, MAD2L1, CENPF, ESPL1/separase, NEK2, PTTG1/securin, ZWILCH and ZWINT) for a genotyping study on samples from healthy individuals (N = 330 to 729) whose lymphocytes had an increased number of CAs compared to persons with a low number of CAs. Genetic variation in individual genes played a minor importance, consistent with the high conservation and selection pressure of the checkpoint system. However, gene pairs were significantly associated with CAs: PTTG1-ZWILCH and PTTG1-ZWINT. MAD2L1 and PTTG1 were the most common partners in any of the two-way interactions. The results suggest that interactions at the level of cohesin (PTTG1) and kinetochore function (ZWINT, ZWILCH and MAD2L1) contribute to the frequency of CAs, suggesting that gene variants at different checkpoint functions appeared to be required for the formation of CAs.

Emerging role of long noncoding RNAs in lung cancer: Current status and future prospects

Lung cancer is the leading cause of cancer-related death worldwide with a 5-year survival rate of less than 15%, despite significant advances in both diagnostic and therapeutic approaches. Combined genomic and transcriptomic sequencing studies have identified numerous genetic driver mutations that are responsible for the development of lung cancer. Importantly, these approaches have also uncovered the widespread expression of "noncoding RNAs" including long noncoding RNAs (LncRNAs), which impact biologic responses through the regulation of mRNA transcription or translation. To date, most studies of the role of noncoding RNAs have focused on LncRNAs, which regulate mRNA translation via the RNA interference pathway. Although many of their attributes, such as patterns of expression, remain largely unknown, LncRNAs have key functions in transcriptional, post-transcriptional, and epigenetic gene regulation. Recent research showed that LncRNAs regulate flowering time in the lung cancer. In this review, we discuss these investigations into long noncoding RNAs were performed almost exclusively in lung cancer. Future work will need to extend these into lung cancer and to analyze how LncRNAs interact to regulate mRNA expression. From a clinical perspective, the targeting of LncRNAs as a novel therapeutic approach will require a deeper understanding of their function and mechanism of action.

Cohesion and the aneuploid phenotype in Alzheimer's disease: A tale of genome instability

Neurons are postmitotic cells that are in permanent cell cycle arrest. However, components of the cell cycle machinery that are expressed in Alzheimer's disease (AD) neurons are showing features of a cycling cell and those attributed to a postmitotic cell as well. Furthermore, the unique physiological operations taking place in neurons, ascribed to "core cell cycle regulators" are also key regulators in cell division. Functions of these cell cycle regulators include neuronal migration, axonal elongation, axon pruning, dendrite morphogenesis and synaptic maturation and plasticity. In this review, we focus on cohesion and cohesion related proteins in reference to their neuronal functions and how impaired centromere/cohesion dynamics may connect cell cycle dysfunction to aneuploidy in AD.

Cdc20 and securin overexpression predict short-term breast cancer survival

BACKGROUND

Cdc20 is an essential component of cell division and responsible for anaphase initiation regulated by securin degradation. Cdc20 function is strongly regulated by the spindle assembly checkpoint to ensure the timely separation of sister chromatids and integrity of the genome. We present the first results on Cdc20 in a large clinical breast cancer material.

METHODS

The study was based on 445 breast cancer patients with up to 20 years of follow-up (mean 10.0 years). DNA content was determined by image cytometry on cell imprints, and Cdc20 and securin immunohistochemistry on tissue microarrays of breast cancer tissue.

RESULTS

In our results, high Cdc20 and securin expression was associated with aneuploid DNA content. In prognostic analyses, high Cdc20 immunoexpression alone and in combination with high securin immunoexpression indicated aggressive course of disease and up to 6.8-fold (P<0.001) risk of breast cancer death. Particularly, high Cdc20 and securin immunoexpression identified a patient subgroup with extremely short, on average 2.4 years, breast cancer survival and triple-negative breast cancer (TNBC) subtype.

CONCLUSIONS

We report for the first time the association of high Cdc20 and securin immunoexpression with extremely poor outcome of breast cancer patients. Our experience indicates that Cdc20 and securin are promising candidates for clinical applications in breast cancer prognostication, especially in the challenging prognostic decisions of TNBC.

Are pre-miR-146a and PTTG1 associated with papillary thyroid cancer?

Papillary thyroid carcinoma (PTC) is the most common endocrine malignancy, with a steadily increasing incidence in the last few decades worldwide. The predisposition to developing this carcinoma by the heterozygous state of rs2910164 within the precursor of the miR-146a has been reported, but recently not confirmed. Interestingly, on the same chromosome, almost 50 kb separate the pre-miR-146a from the pituitary tumor-transforming gene 1 (PTTG1), a proto-oncogene involved in several tumors, including thyroid cancers. In this study, we analyzed, using a case-control design, the genetic association between PTC and the genomic region encompassing pre-miR-146a rs2910164 and PTTG1 rs1862391 and rs2910202. We enrolled 307 affected patients and 206 healthy controls. The possible presence of thyroid nodules in controls was excluded by ultrasonography. All the cases were submitted to single-nucleotide polymorphism (SNP) genotyping of pre-miR-146a and PTTG1, and risk association analyses were carried out. The genotypic and allelic frequencies of pre-miR-146a rs2910164 were not statistically different in the patients and controls, and this SNP was not in linkage disequilibrium with the investigated PTTG1 SNPs. Consistently, meta-analyses, the first including all the affected cases published to date, did not confirm the previously reported association of the heterozygous CG genotype with PTC. The PTTG1 SNPs exhibited the same allelic frequency in the patients and controls and were not associated with the disease. In conclusion, in a well-selected Italian population, neither pre-miR-146a rs2910164 nor PTTG1 rs1862391 and rs2910202 were found to be associated with the risk of developing PTC.