RESUMEN
Lysine acetylation of non-histone proteins plays crucial roles in many cellular processes. In this study, we examine the role of lysine acetylation during sister chromatid separation in mitosis. We investigate the acetylation of securin at K21 by cell-cycle-dependent acetylome analysis and uncover its role in separase-triggered chromosome segregation during mitosis. Prior to the onset of anaphase, the acetylated securin via TIP60 prevents its degradation by the APC/CCDC20-mediated ubiquitin-proteasome system. This, in turn, restrains precocious activation of separase and premature separation of sister chromatids. Additionally, the acetylation-dependent stability of securin is also enhanced by its dephosphorylation. As anaphase approaches, HDAC1-mediated deacetylation of securin promotes its degradation, allowing released separase to cleave centromeric cohesin. Blocking securin deacetylation leads to longer anaphase duration and errors in chromosome segregation. Thus, this study illustrates the emerging role of securin acetylation dynamics in mitotic progression and genetic stability.
Asunto(s)
Cromátides , Lisina , Separasa/metabolismo , Securina/genética , Securina/metabolismo , Cromátides/metabolismo , Acetilación , Lisina/genética , Lisina/metabolismo , Proteínas de Ciclo Celular/metabolismo , Anafase , Endopeptidasas , Segregación CromosómicaRESUMEN
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.
Asunto(s)
Seminoma , Neoplasias Testiculares , Humanos , Masculino , Línea Celular Tumoral , Citoplasma/metabolismo , Regulación Neoplásica de la Expresión Génica , Metaloproteinasa 2 de la Matriz/metabolismo , Proteómica , Securina/genética , Securina/metabolismo , Seminoma/genética , Espectrina/genética , Neoplasias Testiculares/genéticaRESUMEN
Hexavalent chromium [Cr(VI)] is a known human lung carcinogen with widespread exposure in environmental and occupational settings. Despite well-known cancer risks, the molecular mechanisms of Cr(VI)-induced carcinogenesis are not well understood, but a major driver of Cr(VI) carcinogenesis is chromosome instability. Previously, we reported Cr(VI) induced numerical chromosome instability, premature centriole disengagement, centrosome amplification, premature centromere division, and spindle assembly checkpoint bypass. A key regulator of these events is securin, which acts by regulating the cleavage ability of separase. Thus, in this study we investigated securin disruption by Cr(VI) exposure. We exposed human lung cells to a particulate Cr(VI) compound, zinc chromate, for acute (24 h) and prolonged (120 h) time points. We found prolonged Cr(VI) exposure caused marked decrease in securin levels and function. After prolonged exposure at the highest concentration, securin protein levels were decreased to 15.3% of control cells, while securin mRNA quantification was 7.9% relative to control cells. Additionally, loss of securin function led to increased separase activity manifested as enhanced cleavage of separase substrates; separase, kendrin, and SCC1. These data show securin is targeted by prolonged Cr(VI) exposure in human lung cells. Thus, a new mechanistic model for Cr(VI)-induced carcinogenesis emerges with centrosome and centromere disruption as key components of numerical chromosome instability, a key driver in Cr(VI) carcinogenesis.
Asunto(s)
Carcinogénesis , Cromo , Inestabilidad Cromosómica , Humanos , Securina/genética , SeparasaRESUMEN
Chromosome segregation is initiated by cohesin degradation, which is driven by anaphase-promoting complex/cyclosome (APC/C). Chromosome cohesin is removed by activated separase, with the degradation of securin and cyclinB1. Dynamin-related protein 1 (DRP1), a component of the mitochondrial fission machinery, is related to cyclin dynamics in mitosis progression. Here, we show that DRP1 is recruited to the kinetochore by centromeric Centromere protein F (CENP-F) after nuclear envelope breakdown in mouse oocytes. Loss of DRP1 during prometaphase leads to premature cohesin degradation and chromosome segregation. Importantly, acute DRP1 depletion activates separase by initiating cyclinB1 and securin degradation during the metaphase-to-anaphase transition. Finally, we demonstrate that DRP1 is bound to APC2 to restrain the E3 ligase activity of APC/C. In conclusion, DRP1 is a CENP-F-dependent atypical spindle assembly checkpoint (SAC) protein that modulates metaphase-to-anaphase transition by controlling APC/C activity during meiosis I in oocytes.
Asunto(s)
Segregación Cromosómica , Meiosis , Animales , Ratones , Ciclosoma-Complejo Promotor de la Anafase/metabolismo , Proteínas de Ciclo Celular/metabolismo , Dinaminas/metabolismo , Cinetocoros/metabolismo , Oocitos/metabolismo , Securina/genética , Securina/metabolismo , Separasa/metabolismoRESUMEN
Aneuploidy is the leading genetic abnormality causing early miscarriage and pregnancy failure in humans. Most errors in chromosome segregation that give rise to aneuploidy occur during meiosis in oocytes, but why oocyte meiosis is error-prone is still not fully understood. During cell division, cells prevent errors in chromosome segregation by activating the spindle assembly checkpoint (SAC). This control mechanism relies on detecting kinetochore (KT)-microtubule (MT) attachments and sensing tension generated by spindle fibers. When KTs are unattached, the SAC is activated and prevents cell-cycle progression. The SAC is activated first by MPS1 kinase, which triggers the recruitment and formation of the mitotic checkpoint complex (MCC), composed of MAD1, MAD2, BUB3, and BUBR1. Then, the MCC diffuses into the cytoplasm and sequesters CDC20, an anaphase-promoting complex/cyclosome (APC/C) activator. Once KTs become attached to microtubules and chromosomes are aligned at the metaphase plate, the SAC is silenced, CDC20 is released, and the APC/C is activated, triggering the degradation of Cyclin B and Securin, thereby allowing anaphase onset. Compared to somatic cells, the SAC in oocytes is not as effective because cells can undergo anaphase despite having unattached KTs. Understanding why the SAC is more permissive and if this permissiveness is one of the causes of chromosome segregation errors in oocytes still needs further investigation. The present protocol describes the three techniques to comprehensively evaluate SAC integrity in mouse oocytes. These techniques include using nocodazole to depolymerize MTs to evaluate the SAC response, tracking SAC silencing by following the kinetics of Securin destruction, and evaluating the recruitment of MAD2 to KTs by immunofluorescence. Together these techniques probe mechanisms needed to produce healthy eggs by providing a complete evaluation of SAC integrity.
Asunto(s)
Puntos de Control de la Fase M del Ciclo Celular , Huso Acromático , Ciclosoma-Complejo Promotor de la Anafase/genética , Ciclosoma-Complejo Promotor de la Anafase/metabolismo , Aneuploidia , Animales , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Cinetocoros/metabolismo , Ratones , Nocodazol , Oocitos , Securina/genética , Securina/metabolismo , Huso Acromático/metabolismoRESUMEN
Research over the years revealed that precocious anaphase, securin overexpression, and genome instability in both target and nontarget cells are significantly associated with the increased risk of areca nut (AN) and lime-induced oral, esophageal, and gastric cancers. Further, hyperphosphorylation of Rb and histone H3 epigenetic modifications both globally and in the promoter region of the securin gene were demonstrated after AN + lime exposure. This study aims whether the extract of raw AN + lime relaxes chromatin structure which further facilitates the histone H3 epigenetic modifications during the initial phase of carcinogenesis. Three groups of mice (10 in each group) were used. The treated group consumed 1 mg/day/mice of AN extract with lime ad libitum in the drinking water for 60 days. The dose was increased by 1 mg every 60 days. Isolated nuclei were digested with DNaseI and 2 kb and below DNA was eluted from the agarose gel, purified and PCR amplified by using securin and GAPDH primers. Securin and E2F1 expression, pRb phosphorylation, and histone epigenetic modifications were analyzed by immunohistochemistry. The number of DNA fragments within 2 kb in size after DNaseI treatment was higher significantly in AN + lime exposed tissue samples than in the untreated one. The PCR result showed that the number of fragments bearing securin gene promoter and GAPDH gene was significantly higher in AN + lime exposed DNaseI-treated samples. Immunohistochemistry data revealed increased Rb hyperphosphorylation, upregulation of E2F1, and securin in the AN + lime-treated samples. Increased trimethylation of histone H3 lysine 4 and acetylation of H3 lysine 9 and 18 were observed globally in the treated samples. Therefore, the results of this study have led to the hypothesis that AN + lime exposure relaxes the chromatin, changes the epigenetic landscape, and deregulates the Rb-E2F1 circuit which might be involved in the upregulation of securin and some other proto-oncogenes that might play an important role in the initial phases of AN + lime mediated carcinogenesis.
Asunto(s)
Cromatina , Nueces , Extractos Vegetales , Animales , Ratones , Acetilación , Areca/química , Carcinogénesis , Cromatina/genética , Histonas/genética , Histonas/metabolismo , Lisina/genética , Nueces/química , Extractos Vegetales/farmacología , Securina/genética , Securina/metabolismoRESUMEN
Disrupted cell cycle progression underlies the molecular pathogenesis of multiple diseases. Chronic exposure to inorganic arsenic (iAs) is a global health issue leading to multi-organ cancerous and non-cancerous diseases. Exposure to supratherapeutic concentrations of iAs causes cellular accumulation in G2 or M phase of the cell cycle in multiple cell lines by inducing cyclin B1 expression. It is not clear if iAs exposure at doses corresponding to serum levels of chronically exposed populations (â¼100 nM) has any effect on cell cycle distribution. In the present study we investigated if environmentally relevant iAs exposure induced cell cycle disruption and mechanisms thereof employing two human keratinocyte cell lines (HaCaT and Ker-CT), flow cytometry, immunoblots and quantitative real-time PCR (qRT-PCR). iAs exposure (100 nM; 24 h) led to mitotic accumulation of cells in both cell lines, along with the stabilization of ANAPC11 ubiquitination targets cyclin B1 and securin, without affecting their steady state mRNA levels. This result suggested that induction of cyclin B1 and securin is modulated at the level of protein degradation. Moreover, zinc supplementation successfully prevented iAs-induced mitotic accumulation and stabilization of cyclin B1 and securin without affecting their mRNA levels. Together, these data suggest that environmentally relevant iAs exposure leads to mitotic accumulation possibly by displacing zinc from the RING finger subunit of anaphase promoting complex/cyclosome (ANAPC11), the cell cycle regulating E3 ubiquitin ligase. This early cell cycle disruptive effect of environmentally relevant iAs concentration could underpin the molecular pathogenesis of multiple diseases associated with chronic iAs exposure.
Asunto(s)
Subunidad Apc11 del Ciclosoma-Complejo Promotor de la Anafase , Arsénico , Ciclosoma-Complejo Promotor de la Anafase , Arsénico/toxicidad , Línea Celular , Ciclina B1/genética , Suplementos Dietéticos , Humanos , Queratinocitos , ARN Mensajero , Securina , Ubiquitina-Proteína Ligasas , ZincRESUMEN
BACKGROUND: Numerous studies have investigated the clinical significance of securin expression in solid cancers; however, the results have been inconsistent. Hence, we performed a meta-analysis of published studies to assess the clinical value of securin expression in patients with solid cancers. METHODS: The Chinese National Knowledge Infrastructure, Web of Science, PubMed, and EMDASE databases were searched for eligible studies (from inception up to April 2021). Bioinformatics analysis based on The Cancer Genome Atlas dataset was also performed to evaluate the prognostic value of securin expression. RESULTS: A total of 25 articles with 26 studies were included in the meta-analysis. The results of the meta-analysis implied that high securin expression was positively correlated with unfavorable overall survival (OS) (hazard ratioâ =â 1.52, 95% CI, 1.33-1.73; Pâ <â .001) and lymph node metastasis (odd ratioâ =â 2.96, 95% CI, 2.26-3.86; Pâ <â .001). Consistently, our bioinformatics analysis showed that increased securin expression was associated with worse OS and shorter disease-free survival in cancer patients. CONCLUSION: Our study indicated that securin overexpression was positively associated with metastasis and inversely related to the prognosis of patients with solid cancers. However, additional high-quality studies should be conducted to validate these findings.
Asunto(s)
Biomarcadores de Tumor , Biología Computacional , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Humanos , Metástasis Linfática , Pronóstico , Securina/genéticaRESUMEN
The activated spindle assembly checkpoint (SAC) potently inhibits the anaphase-promoting complex/cyclosome (APC/C) to ensure accurate chromosome segregation at anaphase. Early studies have recognized that the SAC should be silenced within minutes to enable rapid APC/C activation and synchronous segregation of chromosomes once all kinetochores are properly attached, but the underlying silencers are still being elucidated. Here, we report that the timely silencing of SAC in fission yeast requires dnt1+, which causes severe thiabendazole (TBZ) sensitivity and increased rate of lagging chromosomes when deleted. The absence of Dnt1 results in prolonged inhibitory binding of mitotic checkpoint complex (MCC) to APC/C and attenuated protein levels of Slp1Cdc20, consequently slows the degradation of cyclin B and securin, and eventually delays anaphase entry in cells released from SAC activation. Interestingly, Dnt1 physically associates with APC/C upon SAC activation. We propose that this association may fend off excessive and prolonged MCC binding to APC/C and help to maintain Slp1Cdc20 stability. This may allow a subset of APC/C to retain activity, which ensures rapid anaphase onset and mitotic exit once SAC is inactivated. Therefore, our study uncovered a new player in dictating the timing and efficacy of APC/C activation, which is actively required for maintaining cell viability upon recovery from the inhibition of APC/C by spindle checkpoint.
Asunto(s)
Proteínas de Ciclo Celular , Tiabendazol , Ciclosoma-Complejo Promotor de la Anafase/genética , Ciclosoma-Complejo Promotor de la Anafase/metabolismo , Proteínas Cdc20/genética , Proteínas Cdc20/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Cinetocoros/metabolismo , Puntos de Control de la Fase M del Ciclo Celular/genética , Securina/genética , Huso Acromático/genética , Huso Acromático/metabolismo , Tiabendazol/metabolismoRESUMEN
Cellular senescence is a form of irreversible growth arrest that cancer cells evade. The cell division cycle protein 20 homolog (Cdc20) is a positive regulator of cell division, but how its dysregulation may relate to senescence is unclear. Here, we find that Cdc20 mRNA and protein expression are downregulated in stress-induced premature senescent lung fibroblasts in a p53-dependent manner. Either Cdc20 downregulation or inhibition of anaphase-promoting complex/cyclosome (APC/C) is sufficient to induce premature senescence in lung fibroblasts, while APC/C activation inhibits stress-induced premature senescence. Mechanistically, we show both Cdc20 downregulation and APC/C inhibition induce premature senescence through glycogen synthase kinase (GSK)-3ß-mediated phosphorylation and downregulation of securin expression. Interestingly, we determined Cdc20 expression is upregulated in human lung adenocarcinoma. We find that downregulation of Cdc20 in non-small cell lung cancer (NSCLC) cells is sufficient to inhibit cell proliferation and growth in soft agar and to promote apoptosis, but not senescence, in a manner dependent on downregulation of securin following GSK-3ß-mediated securin phosphorylation. Similarly, we demonstrate securin expression is downregulated and cell viability is inhibited in NSCLC cells following inhibition of APC/C. Furthermore, we show chemotherapeutic drugs downregulate both Cdc20 and securin protein expression in NSCLC cells. Either Cdc20 downregulation by siRNA or APC/C inhibition sensitize, while securin overexpression inhibits, chemotherapeutic drug-induced NSCLC cell death. Together, our findings provide evidence that Cdc20/APC/C/securin-dependent signaling is a key regulator of cell survival, and its disruption promotes premature senescence in normal lung cells and induces apoptosis in lung cancer cells that have bypassed the senescence barrier.
Asunto(s)
Apoptosis , Carcinoma de Pulmón de Células no Pequeñas , Senescencia Celular , Neoplasias Pulmonares , Humanos , Ciclosoma-Complejo Promotor de la Anafase/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/patología , Proteínas Cdc20/genética , Proteínas Cdc20/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Glucógeno Sintasa Quinasa 3 beta/genética , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Securina/genética , Securina/metabolismoRESUMEN
Separase is a giant cysteine protease and has multiple crucial functions. The most well-known substrate of separase is the kleisin subunit of cohesin, the cleavage of which triggers chromosome segregation during cell division (Uhlmann et al., 1999; Kamenz and Hauf, 2016) [1,2]. Recently, separase has also been found to cleave MCL-1 or BCL-XL proteins to trigger apoptosis (Hellmuth and Stemmann, 2020) [3]. Although substrate recognition through a short sequence right upstream of the cleavage site is well established, recent studies suggested that sequence elements outside this minimum cleavage site are required for optimal cleavage activity and specificity (Rosen et al., 2019; Uhlmann et al., 2000) [4,5]. However, the sequences and their underlying mechanism are largely unknown. To further explore the substrate determinants and recognition mechanism, we carried out sequence alignments and found a conserved motif downstream of the cleavage site in budding yeast. Using Alphafold2 and molecular dynamics simulations, we found this motif is recognized by separase in a conserved cleft near the binding groove of its inhibitor securin. Their binding is mutually exclusive and requires conformation changes of separase. These findings provide deeper insights into substrate recognition and activation of separase, and paved the way for discovering more substrates of separase.
Asunto(s)
Saccharomyces cerevisiae , Saccharomycetales , Proteínas de Ciclo Celular/metabolismo , Segregación Cromosómica , Endopeptidasas/metabolismo , Simulación de Dinámica Molecular , Saccharomyces cerevisiae/metabolismo , Saccharomycetales/metabolismo , Securina/química , Securina/genética , Securina/metabolismo , Separasa/genéticaRESUMEN
Although pituitary tumors are among the most common types of brain tumor, the underlying molecular mechanism of this disease remains obscure. To this end, the role of sirtuin 1 (SIRT1) in pituitary tumors was reported. The results of reverse transcriptionquantitative PCR and immunohistochemistry revealed that sirtuin 1 (SIRT1) expression was downregulated in the tumor tissues of patients with pituitary tumors. In vitro experiments of the present study demonstrated that SIRT1 upregulation suppressed pituitary tumor cell line growth, while SIRT1 downregulation demonstrated the opposite effect. Additionally, it was determined that the enzymatic activity of SIRT1 was required for its cellular function. A mechanistic experiment determined that SIRT1 negatively regulated pituitary tumortransforming gene 1 (PTTG1) expression through the deacetylation of histone (H)3 lysine (K)9ac at the promoter region of PTTG1. Moreover, H3K9ac levels at the PTTG1 promoter were determined to be an essential regulatory element for PTTG1 expression. Thus, it was concluded that the SIRT1/H3K9ac/PTTG1 axis contributed to pituitary tumor formation and may represent a potential therapeutic strategy.
Asunto(s)
Neoplasias Hipofisarias , Línea Celular Tumoral , Proliferación Celular/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Hipofisarias/genética , Neoplasias Hipofisarias/metabolismo , Securina/genética , Sirtuina 1/genética , Sirtuina 1/metabolismoRESUMEN
BACKGROUND: Pituitary tumor transforming gene-1 (PTTG1) transcription factor is identified as carcinogenic and associated with tumor invasiveness, but its role in bladder cancer (BLCA) remains obscure. This research is intended to analyze the aberrant expression and clinical significance of PTTG1 in BLCA, explore the relationship between PTTG1 and tumor microenvironment characteristics and predict its potential transcriptional activity in BLCA tissue. METHODS: We compared the expression discrepancy of PTTG1 mRNA in BLCA and normal bladder tissue, using the BLCA transcriptomic datasets from GEO, ArrayExpress, TCGA, and GTEx. In-house immunohistochemical staining was implemented to determine the PTTG1 protein intensity. The prognostic value of PTTG1 was evaluated using the Kaplan-Meier Plotter. CRISPR screen data was utilized to estimate the effect PTTG1 interference has on BLCA cell lines. We predicted the abundance of the immune cells in the BLCA tumor microenvironment using the microenvironment cell populations-counter and ESTIMATE algorithms. Single-cell RNA sequencing data was applied to identify the major cell types in BLCA, and the dynamics of BLCA progression were revealed using pseudotime analysis. PTTG1 target genes were predicted by CistromeDB. RESULTS: The elevated expression level of PTTG1 was confirmed in 1037 BLCA samples compared with 127 non-BLCA samples, with a standardized mean difference value of 1.04. Higher PTTG1 expression status exhibited a poorer BLCA prognosis. Moreover, the PTTG1 Chronos genetic effect scores were negative, indicating that PTTG1 silence may inhibit the proliferation and survival of BLCA cells. With PTTG1 mRNA expression level increasing, higher natural killer, cytotoxic lymphocyte, and monocyte lineage cell infiltration levels were observed. A total of four candidate targets containing CHEK2, OCIAD2, UBE2L3, and ZNF367 were determined ultimately. CONCLUSIONS: PTTG1 mRNA over-expression may become a potential biomarker for BLCA prognosis. Additionally, PTTG1 may correlate with the BLCA tumor microenvironment and exert transcriptional activity by targeting CHEK2, OCIAD2, UBE2L3, and ZNF367 in BLCA tissue.
Asunto(s)
Neoplasias Hipofisarias , Securina , Neoplasias de la Vejiga Urinaria , Regulación Neoplásica de la Expresión Génica , Humanos , Factores de Transcripción de Tipo Kruppel/metabolismo , Proteínas de Neoplasias/genética , Oncogenes , Neoplasias Hipofisarias/genética , Neoplasias Hipofisarias/metabolismo , Pronóstico , ARN Mensajero/genética , Securina/biosíntesis , Securina/genética , Factores de Transcripción/genética , Microambiente Tumoral/genéticaRESUMEN
Cdc48 (p97/VCP) is a AAA-ATPase that can extract ubiquitinated proteins from their binding partners and can cooperate with the proteasome for their degradation. A fission yeast cdc48 mutant (cdc48-353) shows low levels of the cohesin protease, separase, and pronounced chromosome segregation defects in mitosis. Separase initiates chromosome segregation when its binding partner securin is ubiquitinated and degraded. The low separase levels in the cdc48-353 mutant have been attributed to a failure to extract ubiquitinated securin from separase, resulting in co-degradation of separase along with securin. If true, Cdc48 would be important in mitosis. In contrast, we show here that low separase levels in the cdc48-353 mutant are independent of mitosis. Moreover, we find no evidence of enhanced separase degradation in the mutant. Instead, we suggest that the cdc48-353 mutant uncovers specific requirements for separase translation. Our results highlight a need to better understand how this key mitotic enzyme is synthesized.
Asunto(s)
Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces , Proteína que Contiene Valosina/metabolismo , Mitosis , Schizosaccharomyces/metabolismo , Proteínas de Schizosaccharomyces pombe/genética , Proteínas de Schizosaccharomyces pombe/metabolismo , Securina/genética , Securina/metabolismo , Separasa/genética , Separasa/metabolismoRESUMEN
A large number of studies have reported that microRNA (miR)374c5p plays an important role in the occurrence and development of malignant tumors, but there is no research on the role of miR374c5p in hepatocellular carcinoma (HCC). The aim of the present study was to investigate the role of miR374c5p in HCC and the underlying molecular mechanism. The expression of miR374c5p in HCC tissues and HCC cell lines was analyzed via reverse transcriptionquantitative PCR. The association between miR374c5p and clinical pathology was also analyzed in patients with HCC. KaplanMeier analysis and Cox multivariate analysis were used to evaluate the prognostic significance of miR374c5p in HCC. The biological functions of miR374c5p, including cell proliferation, migration and invasion and its potential molecular mechanism were analyzed in vivo and in vitro. In addition, the molecular mechanism of miR374c5p in HCC was further explored. The results demonstrated that miR374c5p expression was lower in HCC than in matched adjacent tissue samples. Patients with low expression of miR374c5p had poor prognosis and short survival time. Overexpression of miR374c5p inhibited HCC cell proliferation, migration and invasion in vitro. In vivo, it was found that overexpression of miR374c5p significantly inhibited the growth and proliferation of HCC cells. Dualluciferase reporter assays verified that miR374c5p directly targets the 3'untranslated region of pituitary tumortransforming 1 (PTTG1) and regulates PTTG1 expression. In general, it was revealed that miR374c5p regulates the malignant biological behavior of HCC through PTTG1, thereby affecting epithelialmesenchymal transition. Thus, miR374c5p is a potential biological indicator to predict poor prognosis in patients with HCC.
Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , MicroARNs , Securina , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patología , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular/genética , Transición Epitelial-Mesenquimal/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patología , MicroARNs/genética , Securina/genéticaRESUMEN
BACKGROUND AND AIMS: PTTG1 is almost undetectable in adult livers but is highly expressed in hepatocarcinoma. While little is known about its involvement in liver fibrosis, PTTG1 expression is associated with DLK1. We assessed the role of the PTTG1/DLK1 pathway in fibrosis progression and the potential therapeutic effect of PTTG1 silencing in fibrosis. METHODS: Pttg1 and Dlk1 were studied in liver and isolated cell populations of control and fibrotic rats and in human liver biopsies. The fibrotic molecular signature was analysed in Pttg1-/- and Pttg1+/+ fibrotic mice. Finally, Pttg1 silencing was evaluated in rats as a novel antifibrotic therapy. RESULTS: Pttg1 and Dlk1 mRNA selectively increased in fibrotic rats paralleling fibrosis progression. Serum DLK1 concentrations correlated with hepatic collagen content and systemic and portal haemodynamics. Human cirrhotic livers showed greater PTTG1 and DLK1 transcript abundance than non-cirrhotic, and reduced collagen was observed in Pttg1 Pttg1-/- mice. The liver fibrotic molecular signature revealed lower expression of genes related to extracellular matrix remodelling including Mmp8 and 9 and Timp4 and greater eotaxin and Mmp13 than fibrotic Pttg1+/+ mice. Finally, interfering Pttg1 resulted in reduced liver fibrotic area, lower α-Sma and decreased portal pressure than fibrotic animals. Furthermore, Pttg1 silencing decreased the transcription of Dlk1, collagens I and III, Pdgfrß, Tgfrß, Timp1, Timp2 and Mmp2. CONCLUSIONS: Pttg1/Dlk1 are selectively overexpressed in the cirrhotic liver and participate in ECM turnover regulation. Pttg1 disruption decreases Dlk1 transcription and attenuates collagen deposition. PTTG1/DLK1 signalling is a novel pathway for targeting the progression of liver fibrosis.
Asunto(s)
Proteínas de Unión al Calcio , Péptidos y Proteínas de Señalización Intercelular , Proteínas de la Membrana , Neoplasias Hipofisarias , Securina , Animales , Proteínas de Unión al Calcio/genética , Proteínas de Unión al Calcio/metabolismo , Fibrosis , Humanos , Péptidos y Proteínas de Señalización Intercelular/genética , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Hígado/patología , Cirrosis Hepática/patología , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Ratones , Oncogenes , Neoplasias Hipofisarias/metabolismo , Neoplasias Hipofisarias/patología , Ratas , Securina/genética , Securina/metabolismoRESUMEN
BACKGROUND: Sinonasal squamous cell carcinoma (SNSCC) is a main subtype of sinonasal malignancy with unclear pathogenesis. microRNAs (miRNAs) are involved in SNSCC progression. Nevertheless, the role and mechanism of miR-362-3p in SNSCC development are unclear. METHODS: The SNSCC tissues (n = 23) and normal sinonasal samples (n = 13) were harvested. SNSCC cell line RPMI-2650 cells were transfected using Lipofectamine 3000. miR-362-3p and pituitary tumor-transforming gene 1 (PTTG1) were determined by quantitative reverse transcription polymerase chain reaction and western blot. Cell proliferation was analyzed via Cell Counting Kit-8 and 5-ethynyl-2'-deoxyuridine assays. Cell migration and invasion was assessed using wound healing assay and transwell assay. Epithelial-mesenchymal transition (EMT)-associated protein (E-cadherin, N-cadherin and Vimentin) levels were measured via western blot. The binding relationship was analyzed via bioinformatic analysis and dual-luciferase reporter assay. RESULTS: miR-362-3p abundance was decreased in SNSCC samples. miR-362-3p addition constrained cell proliferation, migration, invasion and EMT, but miR-362-3p knockdown played an opposite effect. PTTG1 was targeted and negatively modulated by miR-362-3p. PTTG1 abundance was elevated in SNSCC samples. PTTG1 overexpression mitigated miR-362-3p-modulated suppression of cell proliferation, migration, invasion and EMT in SNSCC cells. CONCLUSION: miR-362-3p repressed cell proliferation, migration, invasion and EMT in SNSCC via targeting PTTG1.
Asunto(s)
Carcinoma de Células Escamosas , MicroARNs , Neoplasias Nasales , Securina/genética , Carcinoma de Células Escamosas/genética , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Regulación Neoplásica de la Expresión Génica , Humanos , MicroARNs/genética , Neoplasias Nasales/genética , OncogenesRESUMEN
Objective To study the stemness characteristics of uterine corpus endometrial carcinoma(UCEC)and its potential regulatory mechanism.Methods Transcriptome sequencing data of UCEC was obtained from The Cancer Genome Atlas.Gene expression profile was normalized by edgeR package in R3.5.1.A one-class logistic regression machine learning algorithm was employed to calculated the mRNA stemness index(mRNAsi)of each UCEC sample.Then,the prognostic significance of mRNAsi and candidate genes was evaluated by survminer and survival packages.The high-frequency sub-pathways mining approach(HiFreSP)was used to identify the prognosis-related sub-pathways enriched with differentially expressed genes(DEGs).Subsequently,a gene co-expression network was constructed using WGCNA package,and the key gene modules were analyzed.The clusterProfiler package was adopted to the function annotation of the modules highly correlated with mRNAsi.Finally,the Human Protein Atlas(HPA)was retrieved for immunohistochemical validation.Results The mRNAsi of UCEC samples was significantly higher than that of normal tissues(t=25.095,P<0.001),and the lower degree of differentiation corresponded to higher mRNAsi in tumor tissues.The mRNAsi of UCEC increased gradually with tumor staging.The prognostic analysis showed that high mRNAsi was correlated with short overall survival in patients with UCEC(χ2=6.864,P=0.0088).There were 570 DEGs between the high-and low-mRNAsi groups.By using the HiFreSP algorithm,we identified that the oocyte meiosis sub-pathway(Oocyte meiosis_1)and cell cycle sub-pathway(Cell cycle_3)had significant prognostic significance.These pathways contained 11 DEGs(MAD2L1,CAMK2A,PTTG1,PLK1,CCNE1,CCNE2,ESPL1,CDC20,CCNB1,CCNB2,and SMC1B),which were significantly associated with the prognosis of UCEC patients.Gene co-expression network showed that mRNAsi,as well as MAD2L1,CAMK2A,and PTTG1,was associated with three gene modules.The immunohistochemical analysis demonstrated that MAD2L1 and PTTG1 showed up-regulated expression while CAMK2A showed down-regulated expression in UCEC,which was consistent with the results of transcriptome sequencing.Conclusions On the basis of machine learning,this study characterizes the stemness characteristics of UCEC.We identify the key sub-pathways related to prognosis and demonstrate that MAD2L1,CAMK2A,PTTG1 are closely related to the stemness of UCEC,which provides insight into the regulatory mechanism of cancer stemness and reveals the potential therapeutic targets of UCEC.
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Neoplasias Endometriales , Células Madre Neoplásicas , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina , Neoplasias Endometriales/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Proteínas Mad2 , Familia de Multigenes , Pronóstico , SecurinaRESUMEN
DNA replication stress activates the S-phase checkpoint that arrests the cell cycle, but it is poorly understood how cells recover from this arrest. Cyclin-dependent kinase (CDK) and protein phosphatase 2A (PP2A) are key cell cycle regulators, and Cdc55 is a regulatory subunit of PP2A in budding yeast. We found that yeast cells lacking functional PP2ACdc55 showed slow growth in the presence of hydroxyurea (HU), a DNA synthesis inhibitor, without obvious viability loss. Moreover, PP2A mutants exhibited delayed anaphase entry and sustained levels of anaphase inhibitor Pds1 after HU treatment. A DNA damage checkpoint Chk1 phosphorylates and stabilizes Pds1. We show that chk1Δ and mutation of the Chk1 phosphorylation sites in Pds1 largely restored efficient anaphase entry in PP2A mutants after HU treatment. In addition, deletion of SWE1, which encodes the inhibitory kinase for CDK or mutation of the Swe1 phosphorylation site in CDK (cdc28F19), also suppressed the anaphase entry delay in PP2A mutants after HU treatment. Our genetic data suggest that Swe1/CDK acts upstream of Pds1. Surprisingly, cdc55Δ showed significant suppression to the viability loss of S-phase checkpoint mutants during DNA synthesis block. Together, our results uncover a PP2A-Swe1-CDK-Chk1-Pds1 axis that promotes recovery from DNA replication stress.
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Anafase/genética , Replicación del ADN/fisiología , Proteína Fosfatasa 2/metabolismo , Saccharomyces cerevisiae/genética , Proteína Quinasa CDC2/genética , Proteína Quinasa CDC2/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1)/genética , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1)/metabolismo , Replicación del ADN/efectos de los fármacos , Proteínas Fluorescentes Verdes/genética , Hidroxiurea/farmacología , Microorganismos Modificados Genéticamente , Mutación , Fosforilación , Proteína Fosfatasa 2/genética , Proteínas Tirosina Quinasas/genética , Proteínas Tirosina Quinasas/metabolismo , Fase S/genética , Saccharomyces cerevisiae/efectos de los fármacos , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Securina/genética , Securina/metabolismoRESUMEN
Background: Lung adenocarcinoma (LUAD) contains a variety of genomic and epigenomic abnormalities; the effective tumor markers related to these abnormalities need to be further explored. Methods: Clustering analysis was performed based on DNA methylation (MET), DNA copy number variation (CNV), and mRNA expression data, and the differences in survival and tumor immune microenvironment (TIME) between subtypes were compared. Further, we evaluated the signatures in terms of both prognostic value and immunological characteristics. Results: There was a positive correlation between MET and CNV in LUAD. Integrative analysis of multi-omics data from 443 samples determined molecular subtypes, iC1 and iC2. The fractions of CD8+ T cells and activated CD4+ T cells were higher, the fraction of Tregs was lower, and the expression level of programmed death-ligand 1 (PD-L1) was higher in iC2 with a poor prognosis showing a higher TIDE score. We selected PTTG1, SLC2A1, and FAM83A as signatures of molecular subtypes to build a prognostic risk model and divided patients into high-risk group and low-risk group representing poor prognosis and good prognosis, respectively, which were validated in 180 patients with LUAD. Further, the low-risk group with lower TIDE score had more infiltrating immune cells. In 100 patients with LUAD, the high-risk group with an immunosuppressive state had a higher expression of PD-L1 and lower counts of CD8+ T cells and dendritic cells. Conclusions: These findings demonstrated that combined multi-omics data could determine molecular subtypes with significant differences of prognosis and TIME in LUAD and suggested potent utility of the signatures to guide immunotherapy.