Elevated expression of C10orf3 (chromosome 10 open reading frame 3) is involved in the growth of human colon tumor

Pre-vaccination transcriptomic profiles of immune responders to the MUC1 peptide vaccine for colon cancer prevention

Self-antigens abnormally expressed on tumors, such as MUC1, have been targeted by therapeutic cancer vaccines. We recently assessed in two clinical trials in a preventative setting whether immunity induced with a MUC1 peptide vaccine could reduce high colon cancer risk in individuals with a history of premalignant colon adenomas. In both trials, there were immune responders and non-responders to the vaccine. Here we used PBMC pre-vaccination and 2 weeks after the first vaccine of responders and non-responders selected from both trials to identify early biomarkers of immune response involved in long-term memory generation and prevention of adenoma recurrence. We performed flow cytometry, phosflow, and differential gene expression analyses on PBMCs collected from MUC1 vaccine responders and non-responders pre-vaccination and two weeks after the first of three vaccine doses. MUC1 vaccine responders had higher frequencies of CD4 cells pre-vaccination, increased expression of CD40L on CD8 and CD4 T-cells, and a greater increase in ICOS expression on CD8 T-cells. Differential gene expression analysis revealed that iCOSL, PI3K AKT MTOR, and B-cell signaling pathways are activated early in response to the MUC1 vaccine. We identified six specific transcripts involved in elevated antigen presentation, B-cell activation, and NF-kB1 activation that were directly linked to finding antibody response at week 12. Finally, a model using these transcripts was able to predict non-responders with accuracy. These findings suggest that individuals who can be predicted to respond to the MUC1 vaccine, and potentially other vaccines, have greater readiness in all immune compartments to present and respond to antigens. Predictive biomarkers of MUC1 vaccine response may lead to more effective vaccines tailored to individuals with high risk for cancer but with varying immune fitness.

Cancer-testis antigen CEP55 serves as a prognostic biomarker and is correlated with immune infiltration and immunotherapy efficacy in pan-cancer

Background: Centrosomal Protein 55 (CEP55) was initially described as a main participant in the final stage of cytokinesis. Further research identified CEP55 as a cancer-testis antigen (CTA) that is aberrantly expressed in different malignancies and a cancer vaccination candidate. The current study aimed to disclose the complete expression of CEP55, its effect on various malignancy prognoses, and its role in the tumor microenvironment. Methods: Transcriptional information regarding tumor and normal tissues, as well as externally validated and protein expression data were gathered from the Cancer Genome Atlas, Genotype-Tissue Expression project, Gene Expression Omnibus, and Human Protein Atlas. We examined the effect of CEP55 on tumor prognosis using Kaplan-Meier (KM) and univariate Cox regression analyses. In addition, we investigated the connections between CEP55 expression and hallmark cancer pathways, immune cell infiltration, and immune regulator expression across malignancies. We constructed and validated a CEP55-related risk model for hepatocellular carcinoma (HCC) and explored the correlations between CEP55 expression and HCC molecular subtypes. Finally, we investigated putative small-molecule drugs targeting CEP55 using a connectivity map (CMap) database and validated them using molecular docking analysis. Findings: CEP55 was aberrantly expressed in most cancers and revealed a prognostic value for several malignancies. Cancers with high CEP55 expression showed significantly enhanced cell cycle, proliferation, and immune-related pathways. For most malignancies, elevated CEP55 expression was associated with the infiltration of myeloid-derived suppressor cells (MDSCs) and Th2 cells. In addition, CEP55 expression was linked to immunomodulators and the potential prediction of immune checkpoint inhibitor (ICI) responses, and strongly associated with distinct molecular HCC subtypes, whereby the CEP55-based nomogram performed well in predicting short- and long-term HCC survival. Finally, we used connectivity map (CMap) and molecular docking analyses to discover three candidate small-molecule drugs that could directly bind to CEP55. Conclusion: CEP55 affected the occurrence and development of various cancers and possibly the regulation of the tumor immune microenvironment. Our findings suggest that CEP55 is a potential biomarker for prognosis and a powerful biomarker for ICI efficacy prediction.

Evaluation of CEP55, SERPINE1 and SMPD3 genes and proteins as diagnostic and prognostic biomarkers in gastric carcinoma in Egyptian patients

Background

Gastric carcinoma (GC) is a fatal disease. Detection of new biomarkers that can be utilized in the early diagnosis of GC is a pressing need. This present study assessed centrosomal protein-55 (CEP55)’ serpin family E member 1 (SERPINE1) and sphingomyelin phosphodiesterase 3 (SMPD3) genes and proteins in gastric adenocarcinoma with different tumor progression features. Thirty surgically resected gastric tissue samples from thirty patients suffered from gastric cancers were obtained. The gastric tissue samples were divided into tumorous (with different stages and grades) and adjacent non-tumorous samples. CEP55, SERPINE1 and SMPD3 genes were assessed by quantitative qRT-PCR, and their proteins were assessed by ELISA in the gastric tissue samples.

Results

As regards SERPINE1, CEP55 genes and proteins, results revealed significant elevations in the GC samples (p < 0.0001). On the contrary, SMPD3 gene and protein revealed significant decreases as compared to non-tumorous samples. The studied genes and proteins showed highly significant specificity and sensitivity in the early detection of GC. SERPINE1 gene and protein revealed highly significant increases and positive correlations, while SMPD3 gene and protein revealed highly significant decreases and negative correlations as the tumor progresses.

Conclusion

CEP55, SERPINE1 and SMPD3 genes and proteins could be used as useful biomarkers for the early detection of GC. SERPINE1 and SMPD3 genes and proteins might be used as risk and protective prognostic factors in GC, respectively.

CEP55 3'-UTR promotes epithelial-mesenchymal transition and enhances tumorigenicity of bladder cancer cells by acting as a ceRNA regulating miR-497-5p

BACKGROUND

Centrosomal protein 55 (CEP55) is implicated in the tumorigenesis of bladder cancer (BC) but the detailed molecular mechanisms are unknown. We aim to develop a potential competing endogenous RNA (ceRNA) network related with CEP55 in BC.

METHODS

We first extracted the expression profiles of RNAs from The Cancer Genome Atlas (TCGA) database and used bioinformatic analysis to establish ceRNAs in BC. Real-time quantity PCR (RT-qPCR) and immunohistochemical analysis were performed to measure CEP55 expression in different bladder cell lines and different grades of cancer. Bioinformatics analysis and luciferase assays were conducted to predict potential binding sites among miR-497-5p, CEP55, parathyroid hormone like hormone (PTHLH) and high mobility group A2 (HMGA2). Tumor xenograft model was used to show the effect of CEP55 3'-UTR on cisplatin therapy. Bioinformatics analysis, luciferase assays, and 5' rapid amplification of cDNA ends (5'RACE) were to explore the function of CEP55 3'-untranslated region (3'-UTR) on targeting miR-497-5p. Western blot and immunofluorescence assays were to detect the epithelial-mesenchymal transition (EMT) induction of CEP55 3'-UTR.

RESULTS

CEP55 expression as well as the expression levels of the oncogenic proteins PTHLH and HMGA2 were upregulated in BC cells while miR-497-5p was downregulated. Low miR-497-5p expression and high CEP55 and HMGA2 expression levels were associated with more advanced tumor clinical stage and pathological grade. Overexpression of the CEP55 3'-UTR promoted the proliferation, migration, and invasion of the EJ cell line in vitro and accelerated EJ-derived tumor growth in nude mice, while inhibition of the CEP55 3'-UTR suppressed all of these oncogenic processes. In addition, CEP55 3'-UTR upregulation reduced the cisplatin sensitivity of BC cell lines and xenograft tumors. Bioinformatics analysis, luciferase assays, and 5'RACE suggested that the CEP55 3'-UTR functions as a ceRNA targeting miR-497-5p, leading to miR-497-5p downregulation and disinhibition of PTHLH and HMGA2 expression. Further, CEP55 downregulated miR-497-5p transcription by promoting NF-[Formula: see text]B signaling. In turn, CEP55 3'-UTR ultimately promotes EMT and tumorigenesis by activating P38MAPK and ERK 1/2 pathways.

CONCLUSIONS

These results suggest that a ceRNA regulatory network involving CEP55 upregulates PTHLH and HMGA2 expression by suppressing endogenous miR-497-5p. We unveiled a novel mechanism of BC metastasis, and could become novel therapeutics targets in BC.

Long intergenic non-protein coding RNA 662 accelerates the progression of gastric cancer through up-regulating centrosomal protein 55 by sponging microRNA-195-5p

Long non-coding RNAs (lncRNAs) are important players in regulating diverse human diseases, including cancers. Nonetheless, the function of long intergenic non-protein coding RNA 662 (LINC00662) in gastric cancer (GC) carcinogenesis and progression remains to be delineated. In the present study, LINC00662, microRNA-195-5p (miR-195-5p) and centrosomal protein 55 (CEP55) mRNA expression levels were quantified by qRT-PCR. GC cell proliferation, migration and invasion were analyzed by CCK-8, BrdU and Transwell assays. Besides, dual-luciferase reporter and RNA pull-down assays were conducted for verifying the targeting relationships of LINC00662, miR-195-5p and CEP55. The regulatory functions of LINC00662 and miR-195-5p on CEP55 were examined utilizing Western blot. In this study, it was revealed that LINC00662 expression level was elevated in GC tissues and cells. LINC00662 overexpression facilitated the malignant biological behaviors of GC cells whereas knockdown of LINC00662 worked oppositely. In terms of mechanism, LINC00662 targeted miR-195-5p to modulate CEP55 expression. In conclusion, LINC00662 facilitates the malignant biological behaviors of GC cells via miR-195-5p/CEP55 axis, and therefore, it may be a promising target for GC treatment.

Centrosome Protein 78 Is Overexpressed in Muscle-Invasive Bladder Cancer and Is Associated with Tumor Molecular Subtypes and Mutation Signatures

BACKGROUND Centrosome aberrations have long been linked to tumorigenesis. Centrosome protein 78 (CEP78) is a centrosome component that is required to regulate the cell cycle, but its role in bladder cancer has not been elucidated. MATERIAL AND METHODS Real-time quantitative polymerase chain reaction and immunohistochemistry were used to examine the expression of CEP78 in bladder cancer tissues and adjacent non-cancer tissues. RESULTS Analysis of the RNA-Seq data from the TCGA (The Cancer Genome Atlas) MIBC cohort (n=408) revealed that CEP78 was overexpressed in tumor tissues, which was confirmed with fresh-frozen and formalin-fixed paraffin-embedded specimens collected from 28 and 33 MIBC patients, respectively, in the present study. The clinicopathological relevance of CEP78 was further investigated. High CEP78 expression was found to be correlated with non-papillary histological type, luminal, basal-squamous and neuronal molecular subtypes, TP53 mutation, RB1 mutation, wild-type FGFR3, PPARG fusion and amplification, high total number of single-nucleotide variants, and high neoantigen load, but it was not associated with tumor stages or overall survival. CONCLUSIONS The results of this study suggest that CEP78 plays in a role in promoting the development of MIBC and could be a novel diagnostic and therapeutic target.

Bioinformatics Analysis of Prognostic miRNA Signature and Potential Critical Genes in Colon Cancer

This study aims to lay a foundation for studying the regulation of microRNAs (miRNAs) in colon cancer by applying bioinformatics methods to identify miRNAs and their potential critical target genes associated with colon cancer and prognosis. Data of differentially expressed miRNAs (DEMs) and genes (DEGs) downloaded from two independent databases (TCGA and GEO) and analyzed by R software resulted in 472 DEMs and 565 DEGs in colon cancers, respectively. Next, we developed an 8-miRNA (hsa-mir-6854, hsa-mir-4437, hsa-mir-216a, hsa-mir-3677, hsa-mir-887, hsa-mir-4999, hsa-mir-34b, and hsa-mir-3189) prognostic signature for patients with colon cancer by Cox proportional hazards regression analysis. To predict the target genes of these miRNAs, we used TargetScan and miRDB. The intersection of DEGs with the target genes predicted for these eight miRNAs retrieved 112 consensus genes. GO and KEGG pathway enrichment analyses showed these 112 genes were mainly involved in protein binding, one-carbon metabolic process, nitrogen metabolism, proteoglycans in cancer, and chemokine signaling pathways. The protein-protein interaction network of the consensus genes, constructed using the STRING database and imported into Cytoscape, identified 14 critical genes in the pathogenesis of colon cancer (CEP55, DTL, FANCI, HMMR, KIF15, MCM6, MKI67, NCAPG2, NEK2, RACGAP1, RRM2, TOP2A, UBE2C, and ZWILCH). Finally, we verified the critical genes by weighted gene co-expression network analysis (WGCNA) of the GEO data, and further mined the core genes involved in colon cancer. In summary, this study identified an 8-miRNA model that can effectively predict the prognosis of colon cancer patients and 14 critical genes with vital roles in colon cancer carcinogenesis. Our findings contribute new ideas for elucidating the molecular mechanisms of colon cancer carcinogenesis and provide new therapeutic targets and biomarkers for future treatment and prognosis.

Centrosomal protein 55: A new paradigm in tumorigenesis

Centrosomal Protein 55 (Cep55), also known as c10orf3 and FLJ10540, was initially discovered as a major player in abscission, the final stage of cytokinesis. Subsequent studies have described its role in regulating the PI3K/AKT pathway, increasing cancer cell stemness, and promoting tumor formation. Clinically, Cep55 has been found to be overexpressed in many cancer types. Cep55 overexpression has been notably associated with tumor stage, tumor aggressiveness, poor prognosis, and metastasis. The present review discusses the role of Cep55 as a crucial biomarker and model in tumorigenesis.

Differential impacts of brain stem oxidative stress and nitrosative stress on sympathetic vasomotor tone

Based on work-done in the rostral ventrolateral medulla (RVLM), this review presents four lessons learnt from studying the differential impacts of oxidative stress and nitrosative stress on sympathetic vasomotor tone and their clinical and therapeutic implications. The first lesson is that an increase in sympathetic vasomotor tone because of augmented oxidative stress in the RVLM is responsible for the generation of neurogenic hypertension. On the other hand, a shift from oxidative stress to nitrosative stress in the RVLM underpins the succession of increase to decrease in sympathetic vasomotor tone during the progression towards brain stem death. The second lesson is that, by having different cellular sources, regulatory mechanisms on synthesis and degradation, kinetics of chemical reactions, and downstream signaling pathways, reactive oxygen species and reactive nitrogen species should not be regarded as a singular moiety. The third lesson is that well-defined differential roles of oxidative stress and nitrosative stress with distinct regulatory mechanisms in the RVLM during neurogenic hypertension and brain stem death clearly denote that they are not interchangeable phenomena with unified cellular actions. Special attention must be paid to their beneficial or detrimental roles under a specific disease or a particular time-window of that disease. The fourth lesson is that, to be successful, future antioxidant therapies against neurogenic hypertension must take into consideration the much more complicated picture than that presented in this review on the generation, maintenance, regulation or modulation of the sympathetic vasomotor tone. The identification that the progression towards brain stem death entails a shift from oxidative stress to nitrosative stress in the RVLM may open a new vista for therapeutic intervention to slow down this transition.

CEP55 is a determinant of cell fate during perturbed mitosis in breast cancer

The centrosomal protein, CEP55, is a key regulator of cytokinesis, and its overexpression is linked to genomic instability, a hallmark of cancer. However, the mechanism by which it mediates genomic instability remains elusive. Here, we showed that CEP55 overexpression/knockdown impacts survival of aneuploid cells. Loss of CEP55 sensitizes breast cancer cells to anti‐mitotic agents through premature CDK1/cyclin B activation and CDK1 caspase‐dependent mitotic cell death. Further, we showed that CEP55 is a downstream effector of the MEK1/2‐MYC axis. Blocking MEK1/2‐PLK1 signaling therefore reduced outgrowth of basal‐like syngeneic and human breast tumors in in vivo models. In conclusion, high CEP55 levels dictate cell fate during perturbed mitosis. Forced mitotic cell death by blocking MEK1/2‐PLK1 represents a potential therapeutic strategy for MYC‐CEP55‐dependent basal‐like, triple‐negative breast cancers.

Genes CEP55, FOXD3, FOXF2, GNAO1, GRIA4, and KCNA5 as potential diagnostic biomarkers in colorectal cancer

Background

Colorectal cancer (CRC) is one of the leading causes of death by cancer worldwide and in need of novel potential diagnostic biomarkers for early discovery.

Methods

We conducted a two-step study. We first employed bioinformatics on data from The Cancer Genome Atlas to obtain potential biomarkers and then experimentally validated some of them on our clinical samples. Our aim was to find a methylation alteration common to all clusters, with the potential of becoming a diagnostic biomarker in CRC.

Results

Unsupervised clustering of methylation data resulted in four clusters, none of which had a known common genetic or epigenetic event, such as mutations or methylation. The intersect among clusters and regulatory regions resulted in 590 aberrantly methylated probes, belonging to 198 differentially expressed genes. After performing pathway and functional analysis on differentially expressed genes, we selected six genes: CEP55, FOXD3, FOXF2, GNAO1, GRIA4 and KCNA5, for further experimental validation on our own clinical samples. In silico analysis demonstrated that CEP55 was hypomethylated in 98.7% and up-regulated in 95.0% of samples. Genes FOXD3, FOXF2, GNAO1, GRIA4 and KCNA5 were hypermethylated in 97.9, 81.1, 80.3, 98.4 and 94.0%, and down-regulated in 98.3, 98.9, 98.1, 98.1 and 98.6% of samples, respectively. Our experimental data show CEP55 was hypomethylated in 97.3% of samples and down-regulated in all samples, while FOXD3, FOXF2, GNAO1, GRIA4 and KCNA5 were hypermethylated in 100.0, 90.2, 100.0, 99.1 and 100.0%, and down-regulated in 68.0, 76.0, 96.0, 95.2 and 84.0% of samples, respectively. Results of in silico and our experimental analyses showed that more than 97% of samples had at least four methylation markers altered.

Conclusions

Using bioinformatics followed by experimental validation, we identified a set of six genes that were differentially expressed in CRC compared to normal mucosa and whose expression seems to be methylation dependent. Moreover, all of these six genes were common in all methylation clusters and mutation statuses of CRC and as such are believed to be an early event in human CRC carcinogenesis and to represent potential CRC biomarkers.

Electronic supplementary material

The online version of this article (10.1186/s12920-019-0501-z) contains supplementary material, which is available to authorized users.

Diagnostic and prognostic value of CEP55 in clear cell renal cell carcinoma as determined by bioinformatics analysis

Clear cell renal cell carcinoma (ccRCC) is one of the most common types of malignant adult kidney tumor. Tumor recurrence and metastasis is the primary cause of cancer-associated mortality in patients with ccRCC. Therefore, identification of efficient diagnostic and prognostic molecular markers may improve survival times. The GSE46699, GSE36895, GSE53000 and GSE53757 gene datasets were downloaded from the Gene Expression Omnibus database and contained 196 ccRCC samples and 164 adjacent normal kidney samples. Bioinformatics analysis was used to integrate the four microarray datasets to identify and analyze differentially expressed genes. Functional analysis revealed that there were 12 genes associated with cancer, based on the tumor-associated gene database. Erb-B2 receptor tyrosine kinase 4, centrosomal protein 55 (CEP55) and vascular endothelial growth factor A are oncogenes, all of which were associated with tumor stage, whereas only CEP55 was significantly associated with survival time as determined by Gene Expression Profiling Interactive Analysis. The mRNA expression levels of CEP55 in ccRCC samples were significantly higher than those observed in adjacent normal kidney tissues based on The Cancer Genome Atlas data and reverse transcription-polymerase chain reaction results. The receiver operating characteristic curve analysis revealed that CEP55 may be considered a diagnostic biomarker for ccRCC with an area under the curve of >0.85 in the training and validation sets. High CEP55 expression was strongly associated with sex, histological grade, stage, T classification, N classification and M classification. Univariate and multivariate Cox proportional hazards analyses demonstrated that CEP55 expression was an independent risk factor for poor prognosis. In addition, gene set enrichment analysis indicated that high CEP55 expression was associated with immunization, cell adhesion, inflammation, the Janus kinase/signal transducer and activator of transcription signaling pathway and cell proliferation. In conclusion, CEP55 was increased in ccRCC samples, and may be considered a potential diagnostic and prognostic biomarker for ccRCC.

Correlation between EZH2 and CEP55 and lung adenocarcinoma prognosis

OBJECTIVE

Recently, accumulated evidence indicates that the enhancer of zeste homologue 2 (EZH2) is highly expressed in a wide range of cancer types, including NSCLC. The downstream genes regulated by EZH2 were screened using bioinformatics analysis. This study aimed to analyse the correlation between the downstream genes of EZH2 and the prognosis of lung adenocarcinoma.

METHODS

Expression and methylation data of lung adenocarcinoma were downloaded from The Cancer Genome Atlas (TCGA) (https://cancergenome.nih.gov/) database, and data were categorized into EZH2 overexpression and EZH2 downregulation groups according to EZH2 expression. The genes that showed opposite trends of methylation and expression changes were screened, and the association of gene expression was calculated. Based on the String database, a protein association analysis was conducted to identify genes related to EZH2, which are referred to as EZH2 regulation candidate genes. According to gene expression (GSE27262) and methylation (GSE66836) chip data in the Gene Expression Omnibus (GEO) (https://www.ncbi.nlm.nih.gov/geo/) database, the genes with differential expression and methylation in lung adenocarcinoma tissues were analysed, and the trends of EZH2 regulation candidate gene expression and methylation were verified to identify the EZH2 regulation candidate genes. Subsequently, MethHC (http://methhc.mbc.nctu.edu.tw/php/index.php) and UALCAN (http://ualcan.path.uab.edu/index.html) were employed to verify changes in the expression and methylation of EZH2 downstream regulation candidate genes and to analyse the correlation between these genes and the prognosis of lung adenocarcinoma.

RESULTS

Expression and methylation data of lung adenocarcinoma were downloaded from TCGA database and categorized into EZH2 overexpression and EZH2 downregulation groups according to EZH2 expression. A total of 337 genes that showed opposite trends of methylation and expression changes were obtained. The protein association analysis using the String (https://string-db.org/) database showed that 61 genes interact with EZH2 and 61 genes represent EZH2 downstream regulation candidate genes. Moreover, 222 genes obtained from GSE27262 and GSE66836 chip data were negatively correlated with methylation and expression changes, and centrosomal protein 55 (CEP55) was identified as the EZH2 downstream regulation candidate gene. CEP55 was upregulated in lung adenocarcinoma tissues and showed low methylation. According to gene expression data from TCGA database, CEP55 and EZH2 exhibit higher levels in lung adenocarcinoma tissue than in adjacent normal tissue. Finally, the survival analysis revealed that EZH2 is not associated with the prognosis of lung adenocarcinoma, while CEP55 is related to lung adenocarcinoma prognosis.

CONCLUSION

Taken together, these results indicate that changes in EZH2 expression lead to changes in CEP55 expression in lung adenocarcinoma, and these changes are associated with its prognosis.

SPAG5 interacts with CEP55 and exerts oncogenic activities via PI3K/AKT pathway in hepatocellular carcinoma

Background

Deregulation of microtubules and centrosome integrity is response for the initiation and progression of human cancers. Sperm-associated antigen 5 (SPAG5) is essential for the spindle apparatus organization and chromosome segregation, but its role in hepatocellular carcinoma (HCC) remains undefined.

Methods

The expression of SPAG5 in HCC were examined in a large cohort of patients by RT-PCR, western blot and IHC. The clinical significance of SPAG5 was next determined by statistical analyses. The biological function of SPAG5 in HCC and the underlying mechanisms were investigated, using in vitro and in vivo models.

Results

Here, we demonstrated that SPAG5 exhibited pro-HCC activities via the activation of PI3K/AKT signaling pathway. SPAG5 expression was increased in HCC and correlated with poor outcomes in two independent cohorts containing 670 patients. High SPAG5 expression was associated with poor tumor differentiation, larger tumor size, advanced TNM stage, tumor vascular invasion and lymph node metastasis. In vitro and in vivo data showed that SPAG5 overexpression promoted tumor growth and metastasis, whereas SPAG5 knockdown led to the opposite phenotypes. SPAG5 interacted with centrosomal protein CEP55 to trigger the phosphorylation of AKT at Ser473. Inhibition of PI3K/AKT signaling markedly attenuated SPAG5-mediated cell growth. Furthermore, SPAG5 expression was suppressed by miR-363-3p which inhibited the activity of SPAG5 mRNA 3’UTR. Ectopic expression of SPAG5 partly abolished the miR-363-3p-caused cell cycle arrest and suppression of cell proliferation and migration.

Conclusions

Collectively, these findings indicate that SPAG5 serves a promising prognostic factor in HCC and functions as an oncogene via CEP55-mediated PI3K/AKT pathway. The newly identified miR-363-3p/SPAG5/CEP55 axis may represent a potential therapeutic target for the clinical intervention of HCC.

Electronic supplementary material

The online version of this article (10.1186/s12943-018-0872-3) contains supplementary material, which is available to authorized users.

PTEN/FLJ10540/PI3K/Akt cascade in experimental brain stem death: A newfound role for a classical tumorigenic signaling pathway

Despite great advances in contemporary medicine, brain death still remains enigmatic and its cellular and molecular mechanisms unsettled. This review summarizes recent findings that substantiate the notion that PTEN/FLJ10540/PI3K/Akt cascade, the classical tumorigenic signaling pathway, is actively engaged in experimental brain stem death. These results were based on a clinically relevant animal model that employs the pesticide mevinphos as the experimental insult in Sprague-Dawley rats to mimic brain stem death in patients died of organophosphate poisoning. The neural substrate investigated is the rostral ventrolateral medulla (RVLM), a brain stem site classically known to maintain arterial pressure (AP) and is established to be the origin of a "life-and-death" signal detected from AP, which reflects brain stem cardiovascular dysregulation that precedes death. Activation of PI3K/Akt signaling pathway in the RVLM upregulates the nuclear factor-κB/nitric oxide synthase II/peroxynitrite cascade, resulting in impairment of brain stem cardiovascular regulation that leads to the loss of the "life-and-death" signal in experimental brain stem death. This process is reinforced by FLJ10540, a PI3K-association protein; and is counteracted by PTEN, a negative regulator of PI3K/Akt signaling. The concept that a classical signaling pathway in tumorigenesis is also an active player in cardiovascular dysregulation in brain stem death provides new ramifications for translational medicine. It promulgates the concept that rather than focusing on a particular disease condition, a new vista for future therapeutic strategy against both fatal eventualities should target at this common cellular cascade.

Prognostic significance of Cep55 in oral squamous cell carcinoma

Objective:

Currently, oral squamous cell carcinoma (OSCC) is one of the most fatal cancers of all head and neck malignancies. Despite advancements in therapy, the mortality and morbidity remain high. Hence, it is essential to identify useful prognostic markers for high-risk individuals with OSCC to decide on treatment protocols. Centrosomal protein 55 ( Cep55), a regulator of the cell cycle, has been considered to play a role in carcinogenesis. Although there are numerous studies on its role in various other epithelial cancers such as breast, ovarian and lung cancers, its significance in the behaviour of OSCC is yet to be studied. The present study aimed to study Cep55 expression in OSCC and correlate with the tumour characteristics and patient survival.

Materials and Methods:

Forty pathologically diagnosed cases of OSCC were included in the study: 20 each of early and advanced OSCC cases. Formalin-fixed paraffin-embedded archival samples were used. The sections were immunohistochemically stained with Cep55 antibody. The expression levels of Cep55 were correlated with clinical parameters and disease outcome.

Results:

A higher expression of Cep55 was observed in advanced stage compared to early stage of OSCC. The Cep55 expression showed no significant relation with respect to clinical staging, pathological grading and site, except for tongue. Cep55 overexpression is significantly associated with poor survival.

Conclusion:

The present study suggests that Cep55 could play an important role in determining the biological behaviour and survival of OSCC patients independent of tumour staging and pathological grading. Thus, assessment of Cep55 expression could navigate the surgeons to plan an appropriate treatment.

High levels of centrosomal protein 55 expression is associated with poor clinical prognosis in patients with cervical cancer

Centrosomal protein 55 (CEP55) has been proposed to have a role in tumor development. However, the expression pattern and clinical relevance of CEP55 has, to the best of our knowledge, not yet been investigated in cervical cancer. The mRNA levels of CEP55 in cervical cancer tissues and paired adjacent non-cancerous tissues were examined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The present study assessed the association between immunohistochemical staining of CEP55 and clinicopathological characteristics and survival rates of patients. Compared with the adjacent non-cancerous tissues, CEP55 expression was significantly increased in cervical tumor tissues, as demonstrated by the results of RT-qPCR. High expression of CEP55 was significantly associated with lymph node metastasis (P=0.008) and advanced tumor stage (P=0.010). Furthermore, CEP55 overexpression in cervical cancer specimens was significantly associated with poor 5-year overall and recurrence-free survival rates (P=0.021 and P=0.010, respectively). The results of multivariate Cox regression analysis revealed that CEP55 expression was a significant, independent predictor for the survival of patients with cervical cancer (hazard ratio=3.057; P=0.035). These data indicated that high CEP55 expression was associated with lymph node metastasis and was an independent predictive factor for an unfavorable prognosis in patients with cervical carcinoma.

MiR-144 suppresses proliferation, invasion, and migration of breast cancer cells through inhibiting CEP55

OBJECTIVE

The study aimed to investigate the molecular mechanism of miR-144 and CEP55 as well as the influence of their interaction on the cell proliferation, migration, invasion, cell cycle and cell apoptosis in breast cancer.

METHODS

In this study, The Cancer Genome Atlas (TCGA, https://tcga-data.nci.nih.gov/ ) database was used for microarray analysis. The expressions of miR-144 and CEP55 in 40 adjacent tissues and 36 tumor tissues were examined by western blot, qRT-PCR and immunohistochemistry. The target relationship between miR-144 and CEP55 was predicted and confirmed by TargetScan and luciferase reporter assay. The cell proliferation, cell cycle and cell apoptosis in different groups were detected by MTT and flow cytometry assays, while wound healing and transwell assays were used for the cell migration and invasion tests. The regulatory effects of miR-144 and CEP55 on breast tumor were verified through nude mouse model in vivo experiment.

RESULTS

MiR-144 was down-regulated in breast cancerous tissues and cells, whereas CEP55 expression was up-regulated in breast cancerous tissues. Moreover, there existed a target relationship between miR-144 and CEP55 and negative correlation on their expressions. MiR-144 could down-regulate CEP55 expression, thereby inhibiting proliferation, invasion, migration, retarding cell cycle and accelerating cell apoptosis. MiR-144 could inhibit cell progression through down-regulating CEP55 in vivo.

CONCLUSION

MiR-144 suppressed cell proliferation, migration, invasion and induced cell cycle arrest and cell apoptosis by repressing CEP55. This might provide a promising therapy for clinical treatment.

Centrosomal protein 55 activates NF-κB signalling and promotes pancreatic cancer cells aggressiveness

Centrosomal protein 55 (CEP55) is a microtubule-bundling protein that participants in cell mitosis. It is overexpressed in several solid tumours and promotes the growth and invasion of cancer cells. However, the role of CEP55 in pancreatic cancer (PANC) remains unclear. Herein, upregulated expression of CEP55 (associated with poor prognosis) was detected in PANC using quantitative real-time reverse transcription PCR, western blotting, and immunohistochemistry. Cell migration, colony formation, wound-healing, and Transwell matrix penetration assays, revealed that upregulation of CEP55 promoted PANC cells proliferation, migration, and invasion in vitro, whereas knockdown of CEP55 attenuated it. In an in vivo murine model, CEP55 overexpression accelerated PANC cells tumourigenicity, together with upregulation of the protein levels of invasion-related proteins matrix metalloproteinase (MMP)2, MMP9, and proliferation-related protein Cyclin D1. Downregulation of CEP55 had the reverse effect. Moreover, the nuclear factor κB (NF-κB)/IκBα signalling pathway, which was activated in CEP55-transduced PANC cells and inhibited in CEP55-silenced PANC cells, contributed to CEP55-mediated PANC cell aggressiveness. This study provided new insights into the oncogenic roles of CEP55 and the mechanism by which the NF-κB pathway is hyperactivated in patients with PANC, indicating that CEP55 is a valuable prognostic factor and a potential therapeutic target in PANC.

CEP55 overexpression predicts poor prognosis in patients with locally advanced esophageal squamous cell carcinoma

Development of esophageal squamous cell carcinoma (ESCC) involves alterations in multiple genes with corresponding proteins. Recent studies have demonstrated that centrosomal protein 55 (CEP55) shares certain features with oncogenes, and CEP55 overexpression is associated with the development and progression of malignant tumors. The present study aimed to analyze, for the first time, whether CEP55 expression is related to clinicopothalogic features in the esophageal squamous cell carcinoma (ESCC), as well as patient survival. A total of 110 patients with mid-thoracic ESCC who suffered from Ivor-Lewis were enrolled. The CEP55 expression profile of these patients in tumour tissues and corresponding healthy esophageal mucosa (CHEM) was detected by immunohistochemistry and semi-quantitative reverse transcription-polymerase chain reaction analyses. Correlations between CEP55 expression and clinicopathological factors were analyzed using χ² test. The log-rank test was employed to calculate survival rate. A Cox regression multivariate analysis was performed to determine independent prognostic factors. The results demonstrated that CEP55 expression in ESCC was significantly higher than that of CHEM (P<0.001). Overexpression of CEP55 was significantly associated with differentiation degree (P=0.022), T stage (P=0.019), lymph node metastasis (P=0.033), clinicopathological staging (P=0.002) and tumor recurrence (P=0.021) in locally advanced ESCC patients. In addition, CEP55 overexpression was significantly associated with reduced overall survival of patients after surgery (P=0.012). The 5-year survival rate of patients without CEP55 overexpression was significantly higher than that of patients with CEP55 overexpression (P=0.012). Therefore, these findings suggest that CEP55 overexpression correlates with poor prognosis in locally advanced ESCC patients.

Suppression of CEP55 reduces cell viability and induces apoptosis in human lung cancer

Centrosomal protein 55 (CEP55), identified as a centrosome‑associated protein, has been reported to be involved in human malignancies. However, its biological function in human lung cancer remains largely unknown. In the present study, we firstly analyzed the expression of CEP55 in 20 pairs of lung cancer and matched non‑tumor tissues using quantitative RT‑PCR analysis and found that CEP55 mRNA was significantly increased in lung cancer tissues compared with that in matched tumor‑adjacent tissues. Then we performed a loss‑of‑function assay using lung cancer cell lines A549 and 95D. Functionally, knockdown of CEP55 markedly inhibited cell viability and proliferation ability as determined by MTT and colony formation assays. Moreover, CEP55‑silenced cells were obviously arrested in the G0/G1 phase and presented significant cell apoptosis as determined using flow cytometric analysis. Mechanistically, western blot analysis further revealed that knockdown of CEP55 decreased the expression of CDK4, p21 and Bcl‑2, while it increased the expression of pro‑apoptotic protein, Bad, caspase‑3 and PARP in 95D cells. In conclusion, our data highlight the crucial role of CEP55 in promoting lung cancer cell proliferation in vitro and its inhibition may be a novel therapeutic strategy for lung cancer.

Low expression of centrosomal protein 78 (CEP78) is associated with poor prognosis of colorectal cancer patients

Background

Centrosomal protein 78 (CEP78) has been characterized as a component of the centrosome required for the regulation of centrosome-related events during the cell cycle, but its role in human cancers remains unclear. This study aimed to investigate the role and the clinical value of CEP78 in colorectal cancer (CRC).

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry were performed to examine CEP78 expression in CRC tissues and adjacent noncancerous tissues. The association between CEP78 expression and clinical outcomes of CRC patients was determined. The effect of CEP78 on cell growth was examined in vitro by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, colony formation, and flow cytometry assays and in vivo using a nude mouse model.

Results

The expression level of CEP78 was significantly lower in tumor tissues than in the adjacent normal tissues (P < 0.01). Low CEP78 expression was significantly associated with poor differentiation (P = 0.003), large tumor size (P = 0.017), lymphatic metastasis (P = 0.034), distant metastasis (P = 0.029), and advanced stage (P = 0.011). Kaplan–Meier analysis indicated that patients with low CEP78 expression had shorter survival than those with high CEP78 expression (P < 0.01). Overexpression of CEP78 in CRC cells significantly reduced cell viability and colony formation in vitro and halted tumor growth in vivo. Further study showed that CEP78 reintroduction in CRC cells resulted in G₂/M phase arrest rather than cell apoptosis.

Conclusions

CEP78 might function as a tumor suppressor and serve as a novel prognostic marker in CRC.

Lentivirus-mediated knockdown of CEP55 suppresses cell proliferation of breast cancer cells

Centrosomal protein 55 (CEP55), as a microtubule-bundling protein, plays an important role in cell cycle regulation. CEP55 has been recognized recently in several human cancers. In this study, we first observed that the mRNA level of CEP55 is commonly up-regulated in breast cancer compared with their normal counterparts as demonstrated by data derived from Oncomine database. To further evaluate the functional role of CEP55 in breast cancer cells. Expression of CEP55 was efficiently knocked down using lentivirus-mediated RNA interference in human breast cancer cell line ZR-75-30, as evidenced by quantitative real-time PCR (qRT-PCR) and Western blot analysis. Further investigations revealed that CEP55 knockdown significantly inhibited cell proliferation and colony formation. Moreover, flow cytometer analysis indicated knockdown of CEP55 induced cell cycle arrested at G0/G1 phase and cell apoptosis. These findings suggest that CEP55 plays a crucial role in promoting breast cancer cell proliferation and it might be a potential therapeutic target in breast cancer.

Prognostic significance of centrosomal protein 55 in stage I pulmonary adenocarcinoma after radical resection

Background

Pulmonary adenocarcinoma is a predominant pathologic non‐small cell lung cancer (NSCLC) with a high morbidity in China. Even at histological stage I, many patients still experience recurrence after radical surgery; therefore, it is critical to determine useful indicators to stratify patients according to recurrent risk. Centrosomal protein 55 (CEP55) shares certain characteristics with oncogenes and aberrant expression of CEP55 can lead to tumorigenesis. Therefore, we aimed to clarify the clinicopathological significance and prognostic value of CEP55 in stage I pulmonary adenocarcinoma.

Methods

We enrolled 106 patients with stage I pulmonary adenocarcinoma who had received complete resection in our study. CEP55 expression levels in the pulmonary tissues of all patients were validated by Western blot analyses and immunohistochemistry. SPSS 17.0 software was employed to analyze the correlation between CEP55 expression and clinicopathological characteristics of patients, as well as prognosis.

Results

CEP55 overexpression was detected in 67 patients (63.2%). Overexpression is associated with tumor differentiation (P = 0.036), T stage (P = 0.000) and visceral pleural invasion (P = 0.009). Patients with CEP55 overexpression had worse survival compared with those with low expression (P = 0.043). Univariate analysis revealed that T stage (P = 0.000), differentiation degree (P = 0.002), visceral pleural invasion (P = 0.000), and tumor size (P = 0.013) were also significant prognostic factors.

Conclusion

CEP55 is a useful predicator to improve stratification of patients with stage I pulmonary adenocarcinoma.

Upregulation of centrosomal protein 55 is associated with unfavorable prognosis and tumor invasion in epithelial ovarian carcinoma

Centrosomal protein 55 (CEP55) is a cell cycle regulator implicated in development of certain cancers. However, characteristics of CEP55 expression and its clinical/prognostic significance are unclear in human epithelial ovarian carcinoma (EOC). Therefore, we investigated the expression and clinicopathological significance of CEP55 in patients with EOC and its role in regulating invasion and metastasis of ovarian cell lines. CEP55 mRNA and protein expression levels were detected by quantitative real-time PCR (qRT-PCR), Western blotting, and immunohistochemistry (IHC). Potential associations of CEP55 expression scores with clinical parameters and patient survival were evaluated. CEP55 function was investigated further using RNA interference, wound healing assay, transwell assay, immunofluorescence analysis, qRT-PCR, and Western blotting. CEP55 was significantly upregulated in ovarian cancer cell lines and lesions compared with normal cells and adjacent noncancerous ovarian tissues. In the 213 EOC samples, CEP55 protein levels were positively correlated with clinical stage (P < 0.001), lymph node metastasis (P < 0.001), intraperitoneal metastasis (P < 0.001), tumor recurrence (P < 0.001), differentiation grade (P < 0.001), residual tumor size (P < 0.001), ascites see tumor cells (P = 0.020), and serum CA153 level (P < 0.001). Moreover, patients with aberrant CEP55 protein expression showed tendencies to receive neoadjuvant chemotherapy (P < 0.001) and cytoreductive surgery (P = 0.020). By contrast, no significant correlation was detected between the protein levels and patient age, histological type, or serum CA125, CA199, CA724, NSE, CEA, and β-HCG levels. Patients with high CEP55 protein expression had shorter overall survival and disease-free survival compared with those with low CEP55 expression. Multivariate analysis implicated CEP55 as an independent prognostic indicator for EOC patients. Additionally, downregulation of CEP55 in ovarian cancer cells remarkably inhibited cellular motility and invasion. Aberrant CEP55 expression may predict unfavorable clinical outcomes in EOC patients and play an important role in regulating invasion in ovarian cancer cells. Thus, CEP55 may serve as a prognostic marker and therapeutic target for EOC.

Structural and biochemical insights into the role of testis-expressed gene 14 (TEX14) in forming the stable intercellular bridges of germ cells

Intercellular bridges are a conserved feature of spermatogenesis in mammalian germ cells and derive from arresting cell abscission at the final stage of cytokinesis. However, it remains to be fully understood how germ cell abscission is arrested in the presence of general cytokinesis components. The TEX14 (testis-expressed gene 14) protein is recruited to the midbody and plays a key role in the inactivation of germ cell abscission. To gain insights into the structural organization of TEX14 at the midbody, we have determined the crystal structures of the EABR [endosomal sorting complex required for transport (ESCRT) and ALIX-binding region] of CEP55 bound to the TEX14 peptide (or its chimeric peptides) and performed functional characterization of the CEP55-TEX14 interaction by multiexperiment analyses. We show that TEX14 interacts with CEP55-EABR via its AxGPPx3Y (Ala793, Gly795, Pro796, Pro797, and Tyr801) and PP (Pro803 and Pro804) sequences, which together form the AxGPPx3YxPP motif. TEX14 competitively binds to CEP55-EABR to prevent the recruitment of ALIX, which is a component of the ESCRT machinery with the AxGPPx3Y motif. We also demonstrate that a high affinity and a low dissociation rate of TEX14 to CEP55, and an increase in the local concentration of TEX14, cooperatively prevent ALIX from recruiting ESCRT complexes to the midbody. The action mechanism of TEX14 suggests a scheme of how to inactivate the abscission of abnormal cells, including cancer cells.

Beyond cytokinesis: the emerging roles of CEP55 in tumorigenesis

CEP55 was initially identified as a pivotal component of abscission, the final stage of cytokinesis, serving to regulate the physical separation of two daughter cells. Over the past 10 years, several studies have illuminated additional roles for CEP55 including regulating the PI3K/AKT pathway and midbody fate. Concurrently, CEP55 has been studied in the context of cancers including those of the breast, lung, colon and liver. CEP55 overexpression has been found to significantly correlate with tumor stage, aggressiveness, metastasis and poor prognosis across multiple tumor types and therefore has been included as part of several prognostic 'gene signatures' for cancer. Here by discussing in depth the functions of CEP55 across different effector pathways, and also its roles as a biomarker and driver of tumorigenesis, we assemble an exhaustive review, thus commemorating a decade of research on CEP55.

Upregulation of FLJ10540, a PI3K-association protein, in rostral ventrolateral medulla impairs brain stem cardiovascular regulation during mevinphos intoxication

FLJ10540, originally identified as a microtubule-associated protein, induces cell proliferation and migration during tumorigenesis via the formation of FLJ10540-PI3K complex and enhancement of PI3K kinase activity. Interestingly, activation of PI3K/Akt cascade, leading to upregulation of nitric oxide synthase II (NOS II)/peroxynitrite signaling in the rostral ventrolateral medulla (RVLM), the brain stem site that maintains blood pressure and sympathetic vasomotor tone, mediates the impairment of brain stem cardiovascular regulation induced by the pesticide mevinphos. We evaluated the hypothesis that upregulation of FLJ10540 in the RVLM is upstream to this repertoire of signaling cascade that underpins mevinphos-induced circulatory depression. Microinjection bilaterally of mevinphos (10nmol) into the RVLM of anesthetized Sprague-Dawley rats induced a progressive hypotension that was accompanied by an increase (Phase I), followed by a decrease (Phase II) of an experimental index for baroreflex-mediated sympathetic vasomotor tone. There was augmentation in FLJ10540 mRNA in the RVLM or FLJ10540 protein in RVLM neurons, both of which were causally and temporally related to an augmentation of binding between the catalytic subunit (p110) and regulatory subunit (p85) of PI3K, phosphorylation of Akt at Thr308 site, and NOS II, superoxide or peroxynitrite level in the RVLM. Immunoneutralization of FJL10540 in the RVLM significantly antagonized those biochemical changes, and blunted the progressive hypotension and the reduced baroreflex-mediated sympathetic vasomotor tone during mevinphos intoxication. We conclude that upregulation of FLJ10540 in the RVLM elicits impairment of brain stem cardiovascular regulation that underpins circulatory depression during mevinphos intoxication via activation of PI3K/Akt/NOS II/peroxynitrite signaling cascade in the RVLM.

Expression and clinical significance of Centrosomal protein 55 (CEP55) in human urinary bladder transitional cell carcinoma

Bladder cancer (BC) is one among the most common and lethal urothelial malignancies worldwide. The expression of cancer-testis (CT) antigens in some tumours and restricted expression among normal tissues make CT antigens as attractive vaccine targets. In this context, we evaluated Centrosomal protein 55 kDa (CEP55), which is specifically expressed in normal human testis and various malignancies. Until the expression pattern of CEP55 in transitional cell carcinoma (TCC) of human urinary bladder and its clinical significance are not known. The aim of the present study is to evaluate mRNA/protein expression of CEP55 in TCCs of urinary bladder and correlate its expression with the clinicopathological characteristics of BC patients. In this study, the methods of quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC) were used to investigate mRNA/protein expression of CEP55 in TCC. Independent Student's t test, ANOVA and Chi-square (χ(2)) were used to analyze the data statistically. We observed CEP55 mRNA overexpression in testis and 48.7% of BC patients. Relative mean fold expression of CEP55 mRNA was found to be significantly (p<0.01) higher in muscle-invasive bladder cancer (MIBC) as compared to non-muscle-invasive bladder cancer (NMIBC) patients (7.88±3.88 vs. 4.75±2.30, p=0.01). CEP55 protein expression was evaluated using IHC and cytoplasmic staining pattern was recorded in formalin fixed, paraffin-embedded (FFPE) bladder tumour tissues. No significant difference was observed in protein expression of CEP55 between the two groups (NMIBC and MIBC patients) (72.2% vs. 69.0%, p=0.774). No significant protein expression of CEP55 was observed among adjacent noncancerous tissues (ANCTs) and benign prostatic hyperplasia (BPH) used as control. Our study results suggest that CEP55 mRNA/protein expression was observed is specific to TCC of human urinary bladder and might be used as a diagnostic biomarker and vaccine target in development of BC specific immunotherapy.

CEP55 contributes to human gastric carcinoma by regulating cell proliferation

Centrosomal protein 55 (CEP55) is the latest found member in the centrosomal relative protein family, which participates in cell-cycle regulation. CEP55 exists in many kinds of normal tissues and tumour cells such as hepatocellular carcinoma, and is important in carcinogenesis. However, the role of CEP55 in the pathogenesis of gastric cancer (GC) remains unclear. The mRNA levels of CEP55 in GC tissues and GC cell lines were examined by quantitative real-time PCR, and the protein expression of CEP55 in GC tissues was detected by Western blot and immunohistochemistry. The role of CEP55 in regulating the proliferation of GC cell lines was investigated both in vitro and in vivo. CEP55 was strongly upregulated in human GC, indicating that CEP55 contributed to carcinogenesis and progression of GC. Ectopic overexpression of CEP55 enhanced the cell proliferation, colony formation, and tumourigenicity of GC cells, whereas CEP55 knockdown inhibited these effects. We discovered that cell transformation induced by CEP55 was mediated by the AKT signalling pathway. Overexpression of CEP55 enhanced the phosphorylation of AKT and inhibited the activity of p21 WAF1/Cip1. In addition, cellular proliferation was suppressed as a result of cell cycle arrest at the G2/M phase in CEP55-knockdown cells. CEP55 expression was elevated in GC compared with normal control tissues. Credible evidence showed that CEP55 can be a potential therapeutic target in GC.

Oncogenic fibulin-5 promotes nasopharyngeal carcinoma cell metastasis through the FLJ10540/AKT pathway and correlates with poor prognosis

Background

Nasopharyngeal carcinoma (NPC) is known for its high metastatic potential and locoregional recurrence, although the molecular alterations that are driving NPC metastasis remain unclear at this time. This study aimed to examine the expression of fibulin-5 in NPC, correlate the results with clinicopathological variables and survival, and to investigate the role of fibulin-5 in human NPC cell lines.

Material and Methods

Standard semi-quantitative-RT-PCR, quantitative-RT-PCR, immunoblotting, and immunohistochemistry were used to investigate the mRNA and protein expression profiles of fibulin-5 in normal and NPC tissues. Immunohistochemistry of fibulin-5 was correlated with clinicopathological characteristics by univariate analyses. NPC cells overexpressing fibulin-5 or fibulin-5-siRNA cells were generated by stable transfection to characterize the molecular mechanisms of fibulin-5-elicited cell growth and metastasis.

Results

Our results demonstrated that fibulin-5 overexpression in NPC specimens and significantly correlated with advanced tumor metastasis indicating a poor 5-year overall survival. Fibulin-5 was mainly expressed in the nucleus in human NPC specimens and cell lines. Functionally, fibulin-5 overexpression yielded fast growth in NPC cells. In addition, fibulin-5 promotes cell metastasis in NPC cells through increased FLJ10540 and phosphor-AKT activity. In contrast, siRNA depletion of fibulin-5 suppressed FLJ10540 expression and phosphor-AKT activity. Suppression of either fibulin-5 or FLJ10540 can cause significant inhibition with regards to cell motility in NPC cells. Finally, immunohistochemical analysis of human aggressive NPC specimens showed a significant and positive correlation between fibulin-5 and FLJ10540 expression.

Conclusion

Higher fibulin-5 expression is not only an important indicator of poor survival, but also contributes to the development of new therapeutic strategies in the FLJ10540/AKT pathway for NPC treatment.

FLJ10540 is associated with tumor progression in nasopharyngeal carcinomas and contributes to nasopharyngeal cell proliferation, and metastasis via osteopontin/CD44 pathway

Background

Nasopharyngeal carcinoma (NPC) is well-known for its highly metastatic characteristics, but little is known of its molecular mechanisms. New biomarkers that predict clinical outcome, in particular the ability of the primary tumor to develop metastatic tumors are urgently needed. The aim of this study is to investigate the role of FLJ10540 in human NPC development.

Methods

A bioinformatics approach was used to explore the potentially important regulatory genes involved in the growth/metastasis control of NPC. FLJ10540 was chosen for this study. Two co-expression strategies from NPC microarray were employed to identify the relationship between FLJ10540 and osteopontin. Quantitative-RT-PCR, immunoblotting, and immunohistochemistry analysis were used to investigate the mRNA and protein expression profiles of FLJ10540 and osteopontin in the normal and NPC tissues to confirm microarray results. TW01 and Hone1 NPC cells with overexpression FLJ10540 or siRNA to repress endogenous FLJ10540 were generated by stable transfection to further elucidate the molecular mechanisms of FLJ10540-elicited cell growth and metastasis under osteopontin stimulation.

Results

We found that osteopontin expression exhibited a positive correlation with FLJ10540 in NPC microarray. We also demonstrated comprehensively that FLJ10540 and osteopontin were not only overexpressed in NPC specimens, but also significantly correlated with advanced tumor and lymph node-metastasis stages, and had a poor 5-year survival rate, respectively. Stimulation of NPC parental cells with osteopontin results in an increase in FLJ10540 mRNA and protein expressions. Functionally, FLJ10540 transfectant alone, or stimulated with osteopontin, exhibited fast growth and increased metastasis as compared to vehicle control with or without osteopontin stimulation. Conversely, knockdown of FLJ10540 by siRNA results in the suppression of NPC cell growth and motility. Treatment with anti-CD44 antibodies in NPC parental cells not only resulted in a decrease of FLJ10540 protein, but also affected the abilities of FLJ10540-elicited cell growth and motility in osteopontin stimulated-NPC cells.

Conclusions

These findings suggest that FLJ10540 may be critical regulator of disease progression in NPC, and the underlying mechanism may involve in the osteopontin/CD44 pathway.

Centrosomal protein 55 (Cep55) stability is negatively regulated by p53 protein through Polo-like kinase 1 (Plk1)

Centrosomal protein 55 (Cep55), which is localized to the centrosome in interphase cells and recruited to the midbody during cytokinesis, is a regulator required for the completion of cell abscission. Up-regulation of Cep55 and inactivation of p53 occur in the majority of human cancers, raising the possibility of a link between these two genes. In this study we evaluated the role of p53 in Cep55 regulation. We demonstrated that Cep55 expression levels are well correlated with cancer cell growth rate and that p53 is able to negatively regulate Cep55 protein and promoter activity. Down-regulation of expression of Cep55 was accompanied by repression of polo-like kinase 1 (Plk1) levels due to p53 induction. Overexpression of Plk1 and knockdown of p53 expression both enhanced the post-translational protein stability of Cep55. BI 2356, a selective Plk1 inhibitor, however, prevented Cep55 accumulation in p53 knockdown cells while persistently keeping Plk1 levels elevated. Our results, therefore, indicate the existence of a p53-Plk1-Cep55 axis in which p53 negatively regulates expression of Cep55, through Plk1 which, in turn, is a positive regulator of Cep55 protein stability.

MRG-binding protein contributes to colorectal cancer development

MRGBP (MORF4-related gene-binding protein; also known as chromosome 20 open reading frame 20) encodes a subunit of the transformation/transcription domain-associated protein (TRRAP)/tat-interacting protein 60 (TIP60)-containing histone acetyltransferase complex. We previously showed that MRGBP was upregulated in the majority of colorectal tumors, and the enhanced expression was associated with cell proliferation. In this study, we investigated its role in colorectal carcinogenesis and searched for genes regulated by MRGBP. Immunohistochemical staining of 22 adenomas and 47 carcinomas in the colon and rectum showed that high levels of MRGBP expression were observed more frequently in carcinomas (45%) than adenomas (5%), linking its role to malignant properties of colorectal tumors. No clinicopathological factors were associated with the levels MRGBP expression in colorectal cancer. Copy number analysis revealed that gene amplification is involved in the elevated expression. A genome-wide expression analysis identified a total of 41 genes upregulated by MRGBP. These genes were implicated in biological processes, including DNA replication, minichromosome maintenance, and cell division. Theses results suggest that MRGBP contributes to colorectal carcinogenesis through rendering advantages in cell proliferation and/or division of cancer cells. Our findings might be helpful for the identification of a specific biomarker for colorectal cancer and the development of diagnostic and/or therapeutic approaches.

The feasibility of Cep55/c10orf3 derived peptide vaccine therapy for colorectal carcinoma

In our previous study, we demonstrated that a peptide derived from the novel centrosome residing protein Cep55/c10orf3 can be targeted by the cytotoxic T lymphocytes (CTLs) in peripheral blood mononuclear cells (PBMCs) of breast carcinoma patients. In this report, we evaluated the feasibility of cancer immunotherapy using Cep55/c10orf3 peptide for colorectal carcinoma (CRC). To evaluate the expression of Cep55/c10orf3 in CRC tissues, we performed immunohistochemical staining of using anti-Cep55/c10orf3 monoclonal antibody. Sixty-three percent cases showed weak positive for Cep55/c10orf3 in total 70 CRC cases. The Cep55/c10orf3 expression intention was collated with high histological grade of CRC. Thus, we hypothesized that Cep55/c10orf3 can also be the target of CTLs in CRC cases. We generated CTLs from PBMCs of human leukocyte antigen (HLA)-A24-positive colorectal carcinoma patients using HLA-A24-restricted Cep55/c10orf3 peptides. Two of 6 colorectal cancer patients were reactive for the Cep55/c10orf3_193(10) peptide, which was the only immunogenic peptide in breast carcinoma patients. CTL clone specific for Cep55/c10orf3_193(10) recognized and lysed HLA-A24 (+) and Cep55/c10orf3 (+) colorectal carcinoma cell lines. In addition, 1 of 6 colorectal carcinoma patients was reactive for the Cep55/c10orf3_402(11) and Cep55/c10orf3_283(12) peptides, but not for Cep55/c10orf3_193(10) with the ELISPOT assay. These observations suggest that the antigenic peptide repertoire presented by HLA-A24 in colorectal carcinoma might be different from that in breast carcinoma. Thus, these peptide vaccination peptide mixture of Cep55/c10orf3_193(10), Cep55/c10orf3_402(11) and Cep55/c10orf3_283(12) might be more effective than a single peptide in the treatment of colorectal carcinoma patients.

Characterization of centrosomal proteins Cep55 and pericentrin in intercellular bridges of mouse testes

Centrosomal protein 55 (Cep55), located in the centrosome in interphase cells and recruited to the midbody during cytokinesis, is essential for completion of cell abscission. Northern blot previously showed that a high level of Cep55 is predominantly expressed in the testis. In the present study, we examined the spatial and temporal expression patterns of Cep55 during mouse testis maturation. We found that Cep55, together with pericentrin, another centrosomal protein, were localized to the intercellular bridges (IBs) interconnecting spermatogenic cells in a syncytium. The IBs were elaborated as a double ring structure formed by an inner ring decorated by Cep55 or pericentrin and an outer ring of mitotic kinesin-like protein 1 (MKLP1) in the male germ cell in early postnatal stages and adulthood. In addition, Cep55 and pericentrin were also localized to the acrosome region and flagellum neck and middle piece in elongated spermatids, respectively. These results suggest that Cep55 and pericentrin are required for the stable bridge between germ cells during spermatogenesis and spermiogenesis.

TEX14 interacts with CEP55 to block cell abscission

In somatic cells, abscission, the physical separation of daughter cells at the completion of cytokinesis, requires CEP55, ALIX, and TSG101. In contrast, cytokinesis is arrested prior to abscission in differentiating male germ cells that are interconnected by TEX14-positive intercellular bridges. We have previously shown that targeted deletion of TEX14 disrupts intercellular bridges in all germ cells and causes male sterility. Although these findings demonstrate that intercellular bridges are essential for spermatogenesis, it remains to be shown how TEX14 and other proteins come together to prevent abscission and form stable intercellular bridges. Using a biochemical enrichment of male germ cell intercellular bridges, we identified additional bridge proteins, including CEP55. Although CEP55 is highly expressed in testes at the RNA level, there is no report of the presence of CEP55 in germ cells. We show here that CEP55 becomes a stable component of the intercellular bridge and that an evolutionarily conserved GPPX3Y motif of TEX14 binds strongly to CEP55 to block similar GPPX3Y motifs of ALIX and TSG101 from interacting and localizing to the midbody. Thus, TEX14 prevents the completion of cytokinesis by altering the destiny of CEP55 from a nidus for abscission to an integral component of the intercellular bridge.

Cep55/c10orf3, a tumor antigen derived from a centrosome residing protein in breast carcinoma

Identification of tumor-associated antigens may facilitate vaccination strategies to treat patients with malignant diseases. We have found that the centrosomal protein, Cep55/c10orf3 acts as a novel breast carcinoma-associated tumor-associated antigen. Cep55/c10orf3 mRNA was detectable in a wide variety of tumor cell lines. Expression was barely detectable in normal tissues except for testis and thymus. Moreover, Cep55/c10orf3 protein could be detected by a monoclonal anti-Cep55/c10orf3 antibody (# 11-55) in 69.8% of breast carcinoma, 25% of colorectal carcinoma, and 57.8% of lung carcinoma tissues. The expression of Cep55/c10orf3 protein did not show any relationship with the hormone receptors such as estrogen receptor and progesterone receptor or expression patterns of p185 HER2/neu. We designed 11 peptides which displayed a human leukocyte antigen-A24 binding motif. One Cep55/c10orf3-peptide, Cep55/c10orf3_193(10) (VYVKGLLAKI), induced cytotoxic T lymphocytes (CTLs) in 3 of 3 patients with Cep55/c10orf3 (# 11-55)-positive breast carcinoma. A Cep55/c10orf3_193(10)-specific CTL clone could also recognize Cep55/c10orf3 (+) displayed on human leukocyte antigen-A24 (+) cancer cell lines. These data indicate that Cep55/c10orf3 peptides were naturally presented by breast cancer cells and can cause CTL clonal expansion in vivo. Monoclonal antibody # 11-55 and the Cep55/c10orf3_193(10) peptides may be useful as part of a therapeutic strategy for hormonal therapy or anti-p185 HER2/neu monoclonal antibody therapy-resistant breast carcinoma patients.

Expression of FLJ10540 is correlated with aggressiveness of oral cavity squamous cell carcinoma by stimulating cell migration and invasion through increased FOXM1 and MMP-2 activity

Matrix metalloproteinase (MMP)-2 plays critical roles in tumor development and in the metastasis of multiple cancers, including human oral cavity squamous cell carcinoma (OCSCC). One of the upstream regulators of MMP-2 is FOXM1, which is overexpressed in a microarray dataset of OCSCC. It is interesting that FLJ10540 exhibits similar gene expression profiles with MMP-2 and FOXM1, raising the possibility that these molecules might participate in MMP-2-elicited cancer progression and metastasis of OCSCC. To examine this connection, we first showed that FLJ10540 was significantly overexpressed in OCSCC. A strong FLJ10540 expression was significantly correlated with an advanced tumor node metastasis stage and the cumulative 5-year survival rate. Thus, an elevated FLJ10540 expression is an indicator of poor survival. Functionally, FLJ10540 had the abilities to stimulate cell migration and invasion in oral cancer cells through increased FOXM1 and MMP-2 expressions. Conversely, the depletion of the FLJ10540 expression by small interfering RNAs suppressed the FOXM1 and MMP-2 protein expressions. The suppression of either FLJ10540 or FOXM1 could cause significant inhibition on cell migratory and invasive ability in oral cancer cells. Finally, the immunohistochemical and western blotting analyses of human aggressive OCSCC specimens showed a significant positive correlation among FLJ10540, FOXM1 and MMP-2 expressions. These findings suggest that FLJ10540 is not only an important prognostic factor but also a new therapeutic target in the FLJ10540/FOXM1/MMP-2 pathway for OCSCC treatment.

VEGFA upregulates FLJ10540 and modulates migration and invasion of lung cancer via PI3K/AKT pathway

BACKGROUND

Lung adenocarcinoma is the leading cause of cancer-related deaths among both men and women in the world. Despite recent advances in diagnosis and treatment, the mortality rates with an overall 5-year survival of only 15%. This high mortality is probably attributable to early metastasis. Although several well-known markers correlated with poor/metastasis prognosis in lung adenocarcinoma patients by immunohistochemistry was reported, the molecular mechanisms of lung adenocarcinoma development are still not clear. To explore novel molecular markers and their signaling pathways will be crucial for aiding in treatment of lung adenocarcinoma patients.

METHODOLOGY/PRINCIPAL FINDINGS

To identify novel lung adenocarcinoma-associated /metastasis genes and to clarify the underlying molecular mechanisms of these targets in lung cancer progression, we created a bioinformatics scheme consisting of integrating three gene expression profile datasets, including pairwise lung adenocarcinoma, secondary metastatic tumors vs. benign tumors, and a series of invasive cell lines. Among the novel targets identified, FLJ10540 was overexpressed in lung cancer tissues and is associated with cell migration and invasion. Furthermore, we employed two co-expression strategies to identify in which pathway FLJ10540 was involved. Lung adenocarcinoma array profiles and tissue microarray IHC staining data showed that FLJ10540 and VEGF-A, as well as FLJ10540 and phospho-AKT exhibit positive correlations, respectively. Stimulation of lung cancer cells with VEGF-A results in an increase in FLJ10540 protein expression and enhances complex formation with PI3K. Treatment with VEGFR2 and PI3K inhibitors affects cell migration and invasion by activating the PI3K/AKT pathway. Moreover, knockdown of FLJ10540 destabilizes formation of the P110-alpha/P85-alpha-(PI3K) complex, further supporting the participation of FLJ10540 in the VEGF-A/PI3K/AKT pathway.

CONCLUSIONS/SIGNIFICANCE

This finding set the stage for further testing of FLJ10540 as a new therapeutic target for treating lung cancer and may contribute to the development of new therapeutic strategies that are able to block the PI3K/AKT pathway in lung cancer cells.

Establishment and molecular cytogenetic characterization of non-small cell lung cancer cell line KU-T1 by multicolor fluorescence in situ hybridization, comparative genomic hybridization, and chromosome microdissection

A human lung adenocarcinoma cell line, designated KU-T1, was established from a Japanese man in Kochi Medical School. Conventional banding and multicolor fluorescence in situ hybridization (M-FISH) analyses of KU-T1 cells revealed a hyperdiploid chromosomal constitution and complex karyotypes. Comparative genomic hybridization showed several chromosomal copy number changes, and five regions that were highly amplified. Two of the five highly amplified regions, 1q and 3q, were identified from distributions of DNA sequences on a metaphase cell by FISH using chromosome microdissection-generated probes hybridized to 1q32 approximately q34 and 3q26 approximately q28, respectively. The 3q probe depicted a homogeneously staining region (hsr) in a derivative chromosome 3 of KU-T1. An hsr probe was regenerated by chromosome microdissection and was hybridized back to KU-T1 and normal metaphases. This hybridization experiment confirmed the probe derived from an hsr and indicated original locations of DNA sequences of hsr on normal chromosome 3. Intense hybridized signals shown at three loci (3p12, 3q26.3, and 3q28) suggests that oncogenes may be involved in the hsr formation. The present study provides a comprehensive analysis of the chromosomal abnormalities, including hsr formation and related oncogenes, in the KU-T1 cell line.

Human ESCRT and ALIX proteins interact with proteins of the midbody and function in cytokinesis

TSG101 and ALIX both function in HIV budding and in vesicle formation at the multivesicular body (MVB), where they interact with other Endosomal Sorting Complex Required for Transport (ESCRT) pathway factors required for release of viruses and vesicles. Proteomic analyses revealed that ALIX and TSG101/ESCRT-I also bind a series of proteins involved in cytokinesis, including CEP55, CD2AP, ROCK1, and IQGAP1. ALIX and TSG101 concentrate at centrosomes and are then recruited to the midbodies of dividing cells through direct interactions between the central CEP55 'hinge' region and GPP-based motifs within TSG101 and ALIX. ESCRT-III and VPS4 proteins are also recruited, indicating that much of the ESCRT pathway localizes to the midbody. Depletion of ALIX and TSG101/ESCRT-I inhibits the abscission step of HeLa cell cytokinesis, as does VPS4 overexpression, confirming a requirement for these proteins in cell division. Furthermore, ALIX point mutants that block CEP55 and CHMP4/ESCRT-III binding also inhibit abscission, indicating that both interactions are essential. These experiments suggest that the ESCRT pathway may be recruited to facilitate analogous membrane fission events during HIV budding, MVB vesicle formation, and the abscission stage of cytokinesis.

Microarray analysis to reveal genes involved in colon carcinogenesis

Sporadic colon cancer is a major cause of death throughout the world. Multistage development of the disease has been associated with remarkable genetic events, mainly at the level of oncogenes and oncosuppressor genes, most notably APC (adenomatous polyposis coli), ras and p53. Despite all of these efforts, the development of a sensitive and convenient diagnostic system for detecting colorectal cancers at the early stage is still in progress. In recent years, cDNA and oligonucleotide microarray technologies have made the analysis of gene expression profiles of colorectal tumours at the genomic level possible and have identified signatures of gene expression associated with pre-cancerous phenotypes, cancers of the early stage and/or metastatic cancer. The contribution of this powerful technology in identification of novel important genes for prognosis, diagnosis and therapy of sporadic colorectal will be discussed.

FLJ10540-elicited cell transformation is through the activation of PI3-kinase/AKT pathway

A significant challenge in the post-genomic era is how to prioritize differentially expressed and uncharacterized novel genes found in hepatocellular carcinoma (HCC) microarray profiling. One such category is cell cycle regulated genes that have only evolved in higher organisms but not in lower eukaryotic cells. Characterization of these genes may reveal some novel human cancer-specific abnormalities. A novel transcript, FLJ10540 was identified. FLJ10540 is overexpressed in HCC as examined by quantitative reverse transcription-polymerase chain reaction and immunohistochemistry. The patients with higher FLJ10540 expression had a poor survival than those with lower FLJ10540 expression. Functional characterization indicates that FLJ10540 displays a number of characteristics associated with an oncogene, including anchorage-independent growth, enhanced cell growth at low serum levels and induction of tumorigenesis in nude mice. FLJ10540-elicited cell transformation is mediated by activation of the phosphatidylinositol 3'-kinase (PI3K)/AKT pathway. Moreover, FLJ10540 forms a complex with PI3K and can activate PI3K activity, which provides a mechanistic basis for FLJ10540-mediated oncogenesis. Together, using a combination of bioinformatics searches and empirical data, we have identified a novel oncogene, FLJ10540, which is conserved only in higher organisms. The finding raises the possibility that FLJ10540 is a potential new therapeutic target for HCC treatment. These findings may contribute to the development of new therapeutic strategies that are able to block the PI3K/AKT pathway in cancer cells.

Cep55, a microtubule-bundling protein, associates with centralspindlin to control the midbody integrity and cell abscission during cytokinesis

We report here an efficient functional genomic analysis by combining information on the gene expression profiling, cellular localization, and loss-of-function studies. Through this analysis, we identified Cep55 as a regulator required for the completion of cytokinesis. We found that Cep55 localizes to the mitotic spindle during prometaphase and metaphase and to the spindle midzone and the midbody during anaphase and cytokinesis. At the terminal stage of cytokinesis, Cep55 is required for the midbody structure and for the completion of cytokinesis. In Cep55-knockdown cells, the Flemming body is absent, and the structural and regulatory components of the midbody are either absent or mislocalized. Cep55 also facilitates the membrane fusion at the terminal stage of cytokinesis by controlling the localization of endobrevin, a v-SNARE required for cell abscission. Biochemically, Cep55 is a microtubule-associated protein that efficiently bundles microtubules. Cep55 directly binds to MKLP1 in vitro and associates with the MKLP1-MgcRacGAP centralspindlin complex in vivo. Cep55 is under the control of centralspindlin, as knockdown of centralspindlin abolished the localization of Cep55 to the spindle midzone. Our study defines a cellular mechanism that links centralspindlin to Cep55, which, in turn, controls the midbody structure and membrane fusion at the terminal stage of cytokinesis.