Centromere Protein A Expression Research Articles

YTHDC1-dependent m6A modification modulated FOXM1 promotes glycolysis and tumor progression through CENPA in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) exhibits heightened aggressiveness compared with other breast cancer (BC) subtypes, with earlier relapse, a higher risk of distant metastasis, and a worse prognosis. Transcription factors play a pivotal role in various cancers. Here, we found that factor forkhead box M1 (FOXM1) expression was significantly higher in TNBC than in other BC subtypes and normal tissues. Combining the findings of Gene Ontology (GO) enrichment analysis and a series of experiments, we found that knockdown of the FOXM1 gene attenuated the ability of TNBC cells to proliferate and metastasize both invivo and invitro. In addition, Spearman's test showed that FOXM1 significantly correlated with glycolysis-related genes, especially centromere protein A (CENPA) in datasets (GSE76250, GSE76124, GSE206912, and GSE103091). The effect of silencing FOXM1 on the inhibition of CENPA expression, TNBC proliferation, migration, and glycolysis could be recovered by overexpression of CENPA. According to MeRIP, the level of m6A modification on FOMX1 decreased in cells treated with cycloleucine (a m6A inhibitor) compared with that in the control group. The increase in FOXM1 expression caused by YTHDC1 overexpression could be reversed by the m6A inhibitor, which indicated that YTHDC1 enhanced FOXM1 expression depending on m6A modification. Therefore, we concluded that the YTHDC1-m6A modification/FOXM1/CENPA axis plays an important role in TNBC progression and glycolysis.

High expression of centromere protein A and its molecular mechanism and clinical significance in prostate cancer: A study based on data mining and immunohistochemistry.

The progression of prostate cancer (PCa) leads to poor prognosis. However, the molecular mechanism of PCa is still not completely clear. This study aimed to elucidate the important role of centromere protein A (CENPA) in PCa. Large numbers of bulk RNA sequencing (RNA-seq) data and in-house immunohistochemistry data were used in analysing the expression level of CENPA in PCa and metastatic PCa (MPCa). Single-cell RNA-seq data was used to explore the expression status of CENPA in different prostate subpopulations. Enrichment analysis was employed to detect the function of CENPA in PCa. Clinicopathological parameters analysis was utilised in analysing the clinical value of CENPA. The results showed that CENPA was upregulated in PCa (standardised mean difference [SMD]=0.83, p=0.001) and MPCa (SMD=0.61, p=0.029). CENPA was overexpressed in prostate cancer stem cells (CSCs) with androgen receptor (AR) negative compared to epithelial cells with AR positive. CENPA may influence the development of PCa through affecting cell cycle. Patients with nodal metastasis had higher expression level of CENPA. And patients with high CENPA expression had poor disease-free survival. Taken together, Overexpression of CENPA may influence the development of PCa by regulating cell cycle and promoting metastasis.

CENPA acts as a prognostic factor that relates to immune infiltrates in gliomas.

Glioma is the most common primary tumor of the central nervous system (CNS). Centromere protein A (CENPA) plays an essential role in ensuring that mitosis proceeds normally. The effect of CENPA on glioma is rarely reported. However, the current study aims to explore whether aberrant CENPA expression promotes glioma progression and the potential mechanisms involved. The GEPIA website, The Cancer Genome Atlas, and the Gene Expression Omnibus (GEO) were used to assess the expression of CENPA in glioma. The results were validated by real-time quantitative polymerase chain reaction and immunohistochemical staining of clinical samples. The relationship between the expression and prognostic value of the CENPA gene in glioma was investigated by Kaplan-Meier (KM) survival analysis with RNA-seq and clinical profiles downloaded from the Chinese Glioma Genome Atlas (CGGA) and UCSC Xena. The association between CENPA and clinical characteristics was also evaluated. Cell Counting Kit-8 (CCK8) assay, wound healing assay using two glioma cell lines, gene set enrichment analysis (GSEA), KEGG and gene ontology (GO) enrichment analysis, immune infiltration analysis, temozolomide (TMZ) sensitivity analysis, and single-cell sequence analysis were performed to explore the underlying mechanisms of high CENPA expression and its effect on glioma development. Finally, we performed a Cox analysis based on the expression of CENPA to predict patient prognosis. CENPA was significantly upregulated in glioma tissue samples and correlated with patient prognosis. Moreover, the downregulation of CENPA inhibited the migration and proliferation of glioma cells. In addition, the expression level of CENPA was significantly correlated with the grade, primary-recurrent-secondary (PRS) type, IDH mutation status, and 1p19q codeletion status. Furthermore, CENPA could serve as an independent prognostic factor for glioma that mainly interferes with the normal progression of mitosis and regulates the tumor immune microenvironment favoring glioma development. CENPA may act as a prognostic factor in patients with glioma and provide a novel target for the treatment of gliomas.

Centromere Protein A Goes Far Beyond the Centromere in Cancers

Centromere dysfunctions leading to numerical chromosome alterations are believed to be closely related to human cancers. As a centromere-specific protein, centromere protein A (CENP-A) replaces the histone H3 in centromeres and is therefore considered a key factor of centromere identity. Researches have shown that CENP-A is overexpressed in many types of human cancers. However, the behavior and function of CENP-A in tumorigenesis have not yet been systematically summarized. In this article, we describe the pleiotropic roles of CENP-A in human cells. Moreover, we provide a comprehensive review of the current knowledge on the relationship between aberrant expression and ectopic localization of CENP-A and tumorigenesis, and the mechanism of the ectopic deposition of CENP-A in cancers. Furthermore, we note that some oncogenic viruses can modulate the expression and localization of this centromere protein along with its chaperone. At last, we also discuss the therapeutic potential of targeting CENP-A for cancer therapy.

High Centromere Protein-A (CENP-A) Expression Correlates with Progression and Prognosis in Gastric Cancer.

PurposeRecent studies have established the ability of centromere protein-A (CENP-A) to perform as an oncogene, regulating tumor progression. The aim of this research was to explore the relationship between CENP-A expression and clinical significance in gastric cancer (GC) patients.Materials and MethodsExperiments with a microarray were conducted using the Affymetrix U133 plus 2.0 GeneChip Array. Upregulated differentially expressed genes (DEGs) were identified via the GEO2R and intersected using a Venn diagram. Bioinformatic databases Omcomine, GEPIA, and Ualcan were applied to investigate the expression level of CENP-A in GC. The real-time quantitative RT-PCR (qRT-PCR) was used to validate the level of CENP-A mRNA in GC. Immunohistochemistry (IHC) was employed to verify the protein levels of CENP-A, while the relationship between CENP-A expression and patients’ clinical parameters in GC was explored through the use of IHC. Kaplan-Meier analysis was conducted to evaluate the prognostic significance of CENP-A. Additionally, the Kaplan-Meier plotter database (KM plotter) was used to verify the prognostic function of CENP-A in GC patients.ResultsThe results indicated that CENP-A was significantly overexpressed, both in protein and mRNA levels of GC tissues, compared to adjacent noncancerous tissues (P<0.05). Furthermore, we observed that CENP-A expression was positively associated with TNM stage, tumor classification, lymph node metastasis, distant metastasis, and Lauren type (P<0.05). Kaplan-Meier analysis showed that patients with an overexpression of CENP-A had significantly poorer overall survival (OS) times (P<0.05). Multivariate analysis suggested CENP-A may serve as an independent predicting factor for the poor outcome of GC patients.ConclusionOur results show that CENP-A upregulation is significantly correlated with advanced tumor progression and poor prognosis. CENP-A may function as a novel potential biomarker for predicting the clinical outcomes of GC patients.

The role of the histone H3 variant CENPA in prostate cancer

Overexpression of centromeric proteins has been identified in a number of human malignancies, but the functional and mechanistic contributions of these proteins to disease progression have not been characterized. The centromeric histone H3 variant centromere protein A (CENPA) is an epigenetic mark that determines centromere identity. Here, using an array of approaches, including RNA-sequencing and ChIP-sequencing analyses, immunohistochemistry-based tissue microarrays, and various cell biology assays, we demonstrate that CENPA is highly overexpressed in prostate cancer in both tissue and cell lines and that the level of CENPA expression correlates with the disease stage in a large cohort of patients. Gain-of-function and loss-of-function experiments confirmed that CENPA promotes prostate cancer cell line growth. The results from the integrated sequencing experiments suggested a previously unidentified function of CENPA as a transcriptional regulator that modulates expression of critical proliferation, cell-cycle, and centromere/kinetochore genes. Taken together, our findings show that CENPA overexpression is crucial to prostate cancer growth.

Leptin regulates the pro-inflammatory response in human epidermal keratinocytes.

The role of leptin in cutaneous wound healing process has been suggested in genetically obese mouse studies. However, the molecular and cellular effects of leptin on human epidermal keratinocytes are still unclear. In this study, the whole-genome-scale microarray analysis was performed to elucidate the effect of leptin on epidermal keratinocyte functions. In the leptin-treated normal human keratinocytes (NHKs), we identified the 151 upregulated and 53 downregulated differentially expressed genes (DEGs). The gene ontology (GO) enrichment analysis with the leptin-induced DEGs suggests that leptin regulates NHKs to promote pro-inflammatory responses, extracellular matrix organization, and angiogenesis. Among the DEGs, the protein expression of IL-8, MMP-1, fibronectin, and S100A7, which play roles in which is important in the regulation of cutaneous inflammation, was confirmed in the leptin-treated NHKs. The upregulation of the leptin-induced proteins is mainly regulated by the STAT3 signaling pathway in NHKs. Among the downregulated DEGs, the protein expression of nucleosome assembly-associated centromere protein A (CENPA) and CENPM was confirmed in the leptin-treated NHKs. However, the expression of CENPA and CENPM was not coupled with those of other chromosome passenger complex like Aurora A kinase, INCENP, and survivin. In cell growth kinetics analysis, leptin had no significant effect on the cell growth curves of NHKs in the normal growth factor-enriched condition. Therefore, leptin-dependent downregulation of CENPA and CENPM in NHKs may not be directly associated with mitotic regulation during inflammation.

CENP-A regulates chromosome segregation during the first meiosis of mouse oocytes.

Proper chromosome separation in both mitosis and meiosis depends on the correct connection between kinetochores of chromosomes and spindle microtubules. Kinetochore dysfunction can lead to unequal distribution of chromosomes during cell division and result in aneuploidy, thus kinetochores are critical for faithful segregation of chromosomes. Centromere protein A (CENP-A) is an important component of the inner kinetochore plate. Multiple studies in mitosis have found that deficiencies in CENP-A could result in structural and functional changes of kinetochores, leading to abnormal chromosome segregation, aneuploidy and apoptosis in cells. Here we report the expression and function of CENP-A during mouse oocyte meiosis. Our study found that microinjection of CENP-A blocking antibody resulted in errors of homologous chromosome segregation and caused aneuploidy in eggs. Thus, our findings provide evidence that CENP-A is critical for the faithful chromosome segregation during mammalian oocyte meiosis.

Insulin Signaling Regulates the FoxM1/PLK1/CENP-A Pathway to Promote Adaptive Pancreatic β Cell Proliferation

Investigation of cell-cycle kinetics in mammalian pancreatic β cells has mostly focused on transition from the quiescent (G0) to G1 phase. Here, we reportthat centromere protein A (CENP-A), which is required for chromosome segregation during the M-phase, is necessary for adaptive β cell proliferation. Receptor-mediated insulin signaling promotes DNA-binding activity of FoxM1 to regulate expression of CENP-A and polo-like kinase-1 (PLK1) by modulating cyclin-dependent kinase-1/2. CENP-A deposition at the centromere is augmented by PLK1 to promote mitosis, while knocking down CENP-A limits β cell proliferation and survival. CENP-A deficiency inβ cells leads to impaired adaptive proliferation inresponse to pregnancy, acute and chronic insulin resistance, and aging in mice. Insulin-stimulated CENP-A/PLK1 protein expression is blunted in islets from patients with type 2 diabetes. These data implicate the insulin-FoxM1/PLK1/CENP-A pathway-regulated mitotic cell-cycle progression as an essential component in the β cell adaptation to delay and/or prevent progression to diabetes.

Elevated expression of the centromere protein-A(CENP-A)-encoding gene as a prognostic and predictive biomarker in human cancers.

Centromere protein-A (CENP-A), a histone-H3 variant, plays an essential role in cell division by ensuring proper formation and function of centromeres and kinetochores. Elevated CENP-A expression has been associated with cancer development. This study aimed to establish whether elevated CENP-A expression can be used as a prognostic and predictive cancer biomarker. Molecular profiling of CENP-A in human cancers was investigated using genomic, transcriptomic and patient information from databases, including COSMIC, Oncomine, Kaplan-Meier plotter and cBioPortal. A network of CENP-A co-expressed genes was derived from cBioPortal and analyzed using Ingenuity Pathway Analysis (IPA) and Oncomine protocols to explore the function of CENP-A and its predictive potential. Transcriptional and post-transcriptional regulation of CENP-A expression was analyzed in silico. It was found that CENP-A expression was elevated in 20 types of solid cancer compared with normal counterparts. Elevated CENP-A expression highly correlated with cancer progression and poor patient outcome. Genomic analysis indicated that the elevated CENP-A expression was not due to alterations in the sequence or copy number of the CENP-A gene. Furthermore, CENP-A can be regulated by key oncogenic proteins and tumor-suppressive microRNAs. CENP-A co-expression network analysis indicated that CENP-A function is associated with cell cycle progression. Oncomine analysis showed a strong correlation between elevated CENP-A expression and oncolytic response of breast cancer patients to taxane-based chemotherapy. In conclusion, elevated CENP-A expression is coupled to malignant progression of numerous types of cancer. It may be useful as a biomarker of poor patient prognosis and as a predictive biomarker for taxane-based chemotherapy.

Abstract 60: Genotranscriptomic meta-analysis of centromere protein A (CENPA): An essential role in human cancer progression

Abstract Background: As the cancer hallmark, genetic instability caused by abnormal cell division, is characterized with the gain or loss of entire chromosomes. The specific histone-H3 variant, centromere protein-A (CENPA), plays essential role in regulating kinetochore assembly, centromere activity and chromosome stability during cell division. However, the biological function of CENPA in human cancer remains largely uncharacterized. This study aims to determine the prognostic value of CENPA expression in cancer patients and the potential therapeutic target in cancer treatment via the genotranscriptomic meta-analysis. Methods: In order to well address the issue, a comprehensive and unbiased genotranscriptomic meta-analysis of CENPA in human cancers was performed with the clinical patient information databases, i.e. COSMIC, Oncomine and cBioPortal. Results: Based on the analysis, it strongly indicated the widespread cancer promoting role of CENPA. There are no gene fusion, very low point mutation (0.15%) and very rare copy number variation (CNV) gain (0.09%) at the CENPA locus in 15214 patient samples across 33 cancer types. However, transcriptomic analyses indicated high correlation of increased CENPA mRNA levels in various solid cancer tissues compared with normal tissues. Furthermore, the poor clinical outcome among 51 clinical cohorts with different cancer types shows significantly correlation with CENPA up-regulation, especially in breast cancer. More importantly, the CENPA up-regulation is also significantly correlated with the metastasis progression and pathology-assessment in breast cancer patients. The high rank of metastatic related genes correlated with CENPA up-regulation is also confirmed in TCGA breast cancer cohorts. Conclusions: The current study highly indicates the essential cancer promoting role of CENPA in human cancer and its value as prognostic marker in clinical use. It also provides rationale for further investigation of CENPA as potential therapeutic target in breast cancer treatment. Citation Format: Xia Sun, Sifeng Qu. Genotranscriptomic meta-analysis of centromere protein A (CENPA): An essential role in human cancer progression. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 60. doi:10.1158/1538-7445.AM2015-60

Expression and prognostic relevance of centromere protein A in primary osteosarcoma

Centromere protein A (CENP-A) is one of the fundamental components of the human active kinetochore and plays important roles in cell-cycle regulation, cell survival, and genetic stability. The aim of the present study was to explore the expression and prognostic significance of CENP-A in osteosarcoma. The results of real-time quantitative PCR and Western blotting analysis revealed an enhanced expression of CENP-A in osteosarcomas relative to adjacent non-tumorous bone tissues at both mRNA and protein levels. Immunohistochemically, 72 of the 123 osteosarcoma specimens (58.5%) had high expression of CENP-A. CENP-A overexpression was significantly correlated with tumor size (P=0.002), poor response to neoadjuvant chemotherapy (P=0.016), local recurrence/lung metastasis (P=0.001), high Ki-67 index (P=0.004), and P53 positivity (P=0.005). Median overall and recurrence-free survival time was significantly shorter in patients with high-CENP-A osteosarcomas than in those with low-CENP-A osteosarcomas. Multivariate analysis identified CENP-A as an independent poor prognostic factor for osteosarcoma. In conclusion, our results demonstrate that elevated CENP-A expression is significantly associated with osteosarcoma progression and has an independent prognostic value in predicting overall and recurrence-free survival for patients with osteosarcoma.

Prognostic value of centromere protein-A expression in patients with epithelial ovarian cancer

Altered expression of centromere protein-A (CENP-A) is observed in various types of human cancers. However, the clinical significance and pathological role of CENP-A in epithelial ovarian cancer (EOC) remains unclear. The main objective of this investigation was to clarify the relationships between CENP-A expression and the clinicopathological features of patients with EOC. Real-time quantitative PCR and Western blot were performed to examine CENP-A expression in 20 pairs of fresh-frozen EOC tissues and corresponding noncancerous tissues. Using immunohistochemistry, we performed a retrospective study of the CENP-A expression levels on 120 archival EOC paraffin-embedded samples. Prognostic outcomes correlated with CENP-A were examined using Kaplan-Meier analysis and Cox proportional hazards model. Our results showed that the expression levels of CENP-A mRNA and protein in EOC tissues were both significantly higher than those in noncancerous tissues. By immunohistochemistry, the data revealed that high CENP-A expression was significantly correlated with pathological grade (P = 0.02) and International Federation of Gynecology and Obstetrics stage (P = 0.006). Consistent with these results, we found that high expression of CENP-A was significantly correlated with poor survival in EOC patients (P < 0.001). Furthermore, Cox regression analyses showed that CENP-A expression was an independent predictor of overall survival. Our data suggest that CENP-A could play an important role in EOC and might serve as a valuable prognostic marker and potential target for gene therapy in the treatment of EOC.

Abstract 160: Pim-1 Preserves Cardiac Stem Cell Proliferation with Age

Rationale Cardiac stem cells (CSC) regulate cardiomyogenesis and support regenerative processes in the heart, but aging adversely affects stem cell repair capacity. Aging is a primary cause of impaired cardiac function characterized by accumulation of senescent cells. CSC senescence is associated with permanent growth arrest that decreases survival signaling and cellular replacement, inevitably diminishing the capacity of the heart to maintain tissue homeostasis. Therefore, promoting CSC growth may improve cardiac performance with age. Pim-1 kinase exhibits protective and proliferative effects in the myocardium but the role of Pim-1 in cardiac aging has not been thoroughly studied. Objective Demonstrate that Pim-1 promotes stem cell growth in the aged myocardium correlating with increased expression of centromere protein A (CENP-A), a kinetochore-associated protein known to support cell proliferation in numerous species and cell types. Methods &amp; Results CENP-A expression levels were evaluated from murine myocardial tissue samples ranging in age from 11 days post coitum to 4 months of age with analysis by immunoblot as well as quantitative PCR. CENP-A expression was colocalized with c-kit as a marker of CSC by immunohistochemical labeling, revealing a decline in CENP-A expression over the time course of postnatal myocardial maturation. The impact of Pim-1 upon CENP-A level was assessed by comparative analysis of non-transgenic mice versus genetically modified transgenic mouse lines expressing either Pim-1 (wild type) or a dominant negative functionally dead Pim-1 mutant. Pim-1 overexpression increases persistence of CENP-A in CSCs with age, as well as the prevalence of cycling CSCs as marked by phosph-H3 expression, while the functionally dead mutant accelerates CENP-A diminution and decreases CSC proliferation. Conclusion CENP-A decline in c-kit positive cells with age provides intriguing evidence of a potential mechanism for the diminished capacity of CSCs to maintain tissue homeostasis. Pim-1 mitigates CENP-A diminution, demonstrating the promising potential of Pim-1 to promote cardiac growth and repair with age.

Centromere protein-A, an essential centromere protein, is a prognostic marker for relapse in estrogen receptor-positive breast cancer

IntroductionCentromere protein A (CENP-A), an essential centromere protein, has been associated with high grade cancers. This study was undertaken to determine if CENP-A is a prognostic factor for breast cancer patients not receiving systemic therapy or predictive of response to tamoxifen or neoadjuvant chemotherapy.MethodsmRNA levels of CENP-A and CENP-B, a centromere protein that binds independently of CENP-A, were measured in breast cancer specimens from 484 patients receiving no systemic therapy, 276 patients receiving tamoxifen, and 233 patients treated with neoadjuvant chemotherapy. Associations between CENP-A, CENP-B, Ki-67, relapse, and chemotherapy response were determined.ResultsCENP-A but not CENP-B was higher in estrogen receptor (ER)-negative tumors than ER-positive tumors and positively correlated with Ki-67 expression. Among patients with ER-positive disease who received no systemic therapy or tamoxifen, higher levels of CENP-A were associated with lower rates of 5-year distant relapse free survival (DRFS). On multivariate analyses including Ki-67, high CENP-A expression had a hazard ratio of 10.9 for relapse in patients with ER-positive disease not receiving systemic therapy (95% CI, 2.86 to 41.78; P = 0.00047) and 1.64 for patients with ER-positive disease receiving tamoxifen (95% CI, 0.99 to 2.71; P = 0.054). CENP-A was not an independent prognostic marker in ER-negative tumors. For both ER-positive and ER-negative tumors, CENP-A was not a significant independent predictor of chemotherapy response.ConclusionsCENP-A was a significant independent prognostic marker for patients with ER-positive breast cancer not treated with systemic therapy but had limited predictive value in tamoxifen treated patients and was not predictive of response to neoadjuvant chemotherapy.

Immunohistochemical Assessment of Expression of Centromere Protein—A (CENPA) in Human Invasive Breast Cancer

Abnormal cell division leading to the gain or loss of entire chromosomes and consequent genetic instability is a hallmark of cancer. Centromere protein –A (CENPA) is a centromere-specific histone-H3-like variant gene involved in regulating chromosome segregation during cell division. CENPA is one of the genes included in some of the commercially available RNA based prognostic assays for breast cancer (BCa)—the 70 gene signature MammaPrint® and the five gene Molecular Grade Index (MGISM). Our aim was to assess the immunohistochemical (IHC) expression of CENPA in normal and malignant breast tissue. Clinically annotated triplicate core tissue microarrays of 63 invasive BCa and 20 normal breast samples were stained with a monoclonal antibody against CENPA and scored for percentage of visibly stained nuclei. Survival analyses with Kaplan–Meier (KM) estimate and Cox proportional hazards regression models were applied to assess the associations between CENPA expression and disease free survival (DFS). Average percentage of nuclei visibly stained with CENPA antibody was significantly higher (p = 0.02) in BCa than normal tissue. The 3-year DFS in tumors over-expressing CENPA (>50% stained nuclei) was 79% compared to 85% in low expression tumors (<50% stained nuclei). On multivariate analysis, IHC expression of CENPA showed weak association with DFS (HR > 60.07; p = 0.06) within our small cohort. To the best of our knowledge, this is the first published report evaluating the implications of increased IHC expression of CENPA in paraffin embedded breast tissue samples. Our finding that increased CENPA expression may be associated with shorter DFS in BCa supports its exploration as a potential prognostic biomarker.

Hepatitis B virus X protein mutant upregulates CENP-A expression in hepatoma cells

The carcinogenic role of hepatitis B virus x protein (HBx) in hepatocellular carcinoma (HCC) remains largely unknown. Centromere protein A (CENP-A) has been found to be frequently overexpressed in HCC. In the present study, we aimed to investigate the role of HBx in regulating CENP-A activity in HCC carcinogenesis. CENP-A expression was examined and the HBx gene was sequenced in 20HBsAg-positive HCC patients and corresponding non-cancerous liver tissues. The influence of HBx mutants on CENP-A expression in HepG2 cells was analyzed by a series of assays. We found that CENP-A expression was significantly elevated in HCC tissues. HBx deletion, especially the COOH-terminal deletion of HBx is a frequent event in HBV-associated HCC tissues. A positive correlation was found between CENP-A expression and HBx COOH mutation in HCC tissues. HBx mutant increased the expression of the CENP-A mRNA and protein compared with full-length HBx. However, HBx did not directly interact with CENP-A. It is concluded that overexpression of CENP-A is closely associated with HBx COOH mutation in HCC. HBx mutant can increase CENP-A expression, probably through a mechanism independent of their physical combination, and thereby it may represent a potential therapeutic strategy for HCC.

ShRNA-Targeted Centromere Protein A Inhibits Hepatocellular Carcinoma Growth

BackgroundCentromere protein A (CENP-A) plays important roles in cell-cycle regulation and genetic stability. Herein, we aimed to investigate its expression pattern, clinical significance, and biological function in hepatocellular carcinoma (HCC).Methodology/Principal FindingsCENP-A expression at the mRNA and protein levels was examined in 20 pairs of fresh HCCs and corresponding nontumor liver tissues. Immunohistochemistry for CENP-A was performed on 80 paraffin-embedded HCC specimens, and the clinical significance of its expression was analyzed. A human HCC cell line HepG2 with high abundance of CENP-A was used to study the effects of manipulating CENP-A on HCC growth. Quantitative real-time polymerase chain reaction arrays and Western blot analysis were employed to identify the cell-cycle control- and apoptosis-related genes regulated by CENP-A. The results showed that CENP-A was aberrantly overexpressed in HCCs relative to adjacent nontumor tissues. This overexpression was significantly associated with positive serum HBsAg status, increased histological grade, high Ki-67 index and P53 immunopositivity. Knockdown of CENP-A in HepG2 cells reduced cell proliferation, blocked cell cycle at the G1 phase, and increased apoptosis. The antiproliferative effects of CENP-A silencing were also observed in vivo. Conversely, CENP-A overexpression promoted HCC cell growth and reduced apoptosis. Furthermore, many genes implicated in cell-cycle regulation and apoptosis, including CHK2, P21waf1, P27 Kip1, SKP2, cyclin G1, MDM2, Bcl-2, and Bax, were deregulated by manipulating CENP-A.Conclusions/SignificanceOverexpression of CENP-A is frequently observed in HCC. Targeting CENP-A can inhibit HCC growth, likely through the regulation of a large number genes involved in cell-cycle progression and apoptosis, and thereby represents a potential therapeutic strategy for this malignancy.

Centromere protein A (CENP-A) dynamics in human pluripotent stem cell self renewal, differentiation and dna repair

OBJECTIVE: Accurate chromosome segregation is dependent on the expression of histone H3 variant CENP-A. Reduced expression of CENP-A in somatic cells results in chromosome misalignment and apoptosis. Compared to somatic cells, CENP-A is highly expressed in the human oocyte and in human embryonic stem cells (hESCs). Our objective is to study the significance of high CENP-A mRNA levels in hESCs and in human induced pluripotent stem cells (hIPSCs) to elucidate its role in early human development. DESIGN: All experiments were compared to somatic cells and performed with and without differentiation of stem cells. CENP-A levels were reduced using shRNA lentiviral technology and assays were compared to lentiviral controls. MATERIALS AND METHODS: Two independent HESC and hIPSC lines were used. BJ fibroblasts were used as control. PCR and Western blot were done for CENP-A expression. Propidium Iodide for Cell cycle profile and Annexin assay for apoptosis were used. Immunohistochemistry was used to localize CENP-A. Two-sample student t-test was used for statistics. RESULTS: Reduction of CENP-A in hESCs and hIPSCs is not lethal and does not result in aneuploidy suggesting lower CENP-A need to maintain a functional centromere. CENP-A depleted cells undergo apoptosis upon differentiation suggesting higher CENP-A need to maintain a functional centromere with differentiation. Upon DNA damage, CENP-A moves from centromeres into multiple small nuclear foci, and hESCs with depleted CENP-A do not to mount an effective response to DNA damage. CONCLUSION: Our results indicate that human pluripotent cells may have evolved a novel mechanism for maintaining genomic integrity by lowering amount of CENP-A required for a functional centromere. We also show that CENP-A mRNA reserve is required to maintain functional centromere with differentiation and to repair DNA damage. These results highlights the unique biology of the early human embryo which may have evolved to support rapid cell divisions while maintaining genomic integrity.

Expression of centromere protein A in hepatocellular carcinoma

To study the expression of centromere protein A (CENP-A) and its significance in hepatocellular carcinoma (HCC) and adjacent non-neoplastic liver tissue. The expression levels of CENP-A mRNA in 20 samples of HCC and adjacent non-neoplastic liver tissue were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and real-time quantitative polymerase chain reaction (qRT-PCR). Immunohistochemical study for CENP-A and p53 proteins was also performed on tissue microarrays containing 80 samples of HCC and adjacent liver tissue. The expression level of CENP-A mRNA in HCC (0.64 +/- 0.18) was higher than that in adjacent non-neoplastic liver tissue (0.09 +/- 0.09) (t = 12.78, P < 0.01). Of the 80 samples of HCC, 57 cases (71.25%) and 60 cases (75%) expressed CENP-A and p53 proteins respectively. The positivity rates of CENP-A and p53 proteins in non-neoplastic liver tissue were 43.75% (35/80) and 16.25% (13/80) respectively. There was a statistically significant difference in CENP-A and p53 protein expression between HCC and non-neoplastic liver tissue (P < 0.01). The coincident rate between CENP-A and p53 expression was 88.75% (71/80). Expression of CENP-A protein showed a positive correlation with that of p53 protein (r = 0.57, P < 0.01). The over-expression of CENP-A occurs at transcriptional level and may be related to malignant proliferation of HCC via possible interaction with p53 gene.