Aurora A, centrosome structure, and the centrosome cycle

Therapeutic Strategies for Idiopathic Pulmonary Fibrosis - Thriving Present and Promising Tomorrow

Idiopathic pulmonary fibrosis (IPF) is a continuous, progressive, and lethal age-related respiratory disease. It is characterized by condensed and rigid lung tissue, which leads to a decline in the normal functioning of the lungs. The pathophysiology of IPF has still not been completely elucidated, so current strategies are lagging behind with respect to improving the condition of patients with IPF and increasing their survival rate. The desire for a better understanding of the pathobiology of IPF and its early detection has led to the identification of various biomarkers associated with IPF. The use of drugs such as pirfenidone and nintedanib as a safe and effective treatment alternative have marked a new chapter in the treatment of IPF. However, nonpharmacological therapies, involving long-term oxygen therapy, transplantation of the lungs, pulmonary rehabilitation, ventilation, and palliative care for cough and dyspnea, are still considered to be beneficial as supplementary methods for IPF therapy. A major risk factor for IPF is aging, with associated hallmarks such as telomere attrition, senescence, epigenetic drift, stem cell exhaustion, loss of proteostasis, and mitochondrial dysfunction. These are promising earmarks for the development of potential therapy for the disease. In this review, we have discussed current and emerging novel therapeutic strategies for IPF, especially for targets associated with age-related mechanisms.

Assessment of AURKA expression and prognosis prediction in lung adenocarcinoma using machine learning-based pathomics signature

Objective

This study aimed to develop quantitative feature-based models from histopathological images to assess aurora kinase A (AURKA) expression and predict the prognosis of patients with lung adenocarcinoma (LUAD).

Methods

A dataset of patients with LUAD was derived from the cancer genome atlas (TCGA) with information on clinical characteristics, RNA sequencing and histopathological images. The TCGA-LUAD cohort was randomly divided into training (n = 229) and testing (n = 98) sets. We extracted quantitative image features from histopathological slides of patients with LUAD using computational approaches, constructed a predictive model for AURKA expression in the training set, and estimated their predictive performance in the test set. A Cox proportional hazards model was used to assess whether the pathomic scores (PS) generated by the model independently predicted LUAD survival.

Results

High AURKA expression was an independent risk factor for overall survival (OS) in patients with LUAD (hazard ratio = 1.816, 95 % confidence intervals = 1.257-2.623, P = 0.001). The model based on histopathological image features had significant predictive value for AURKA expression: the area under the curve of the receiver operating characteristic curve in the training set and validation set was 0.809 and 0.739, respectively. Decision curve analysis showed that the model had clinical utility. Patients with high PS and low PS had different survival rates (P = 0.019). Multivariate analysis suggested that PS was an independent prognostic factor for LUAD (hazard ratio = 1.615, 95 % confidence intervals = 1.071-2.438, P = 0.022).

Conclusion

Pathomics models based on machine learning can accurately predict AURKA expression and the PS generated by the model can predict LUAD prognosis.

CCHCR1-astrin interaction promotes centriole duplication through recruitment of CEP72

BACKGROUND

The centrosome is one of the most important non-membranous organelles regulating microtubule organization and progression of cell mitosis. The coiled-coil alpha-helical rod protein 1 (CCHCR1, also known as HCR) gene is considered to be a psoriasis susceptibility gene, and the protein is suggested to be localized to the P-bodies and centrosomes in mammalian cells. However, the exact cellular function of HCR and its potential regulatory role in the centrosomes remain unexplored.

RESULTS

We found that HCR interacts directly with astrin, a key factor in centrosome maturation and mitosis. Immunoprecipitation assays showed that the coiled-coil region present in the C-terminus of HCR and astrin respectively mediated the interaction between them. Astrin not only recruits HCR to the centrosome, but also protects HCR from ubiquitin-proteasome-mediated degradation. In addition, depletion of either HCR or astrin significantly reduced centrosome localization of CEP72 and subsequent MCPH proteins, including CEP152, CDK5RAP2, and CEP63. The absence of HCR also caused centriole duplication defects and mitotic errors, resulting in multipolar spindle formation, genomic instability, and DNA damage.

CONCLUSION

We conclude that HCR is localized and stabilized at the centrosome by directly binding to astrin. HCR are required for the centrosomal recruitment of MCPH proteins and centriolar duplication. Both HCR and astrin play key roles in keeping normal microtubule assembly and maintaining genomic stability.

Haspin participates in AURKB recruitment to centromeres and contributes to chromosome congression in male mouse meiosis

Chromosome segregation requires that centromeres properly attach to spindle microtubules. This essential step regulates the accuracy of cell division and therefore must be precisely regulated. One of the main centromeric regulatory signaling pathways is the Haspin-H3T3ph-chromosomal passenger complex (CPC) cascade, which is responsible for the recruitment of the CPC to the centromeres. In mitosis, Haspin kinase phosphorylates histone H3 at threonine 3 (H3T3ph), an essential epigenetic mark that recruits the CPC, whose catalytic component is Aurora B kinase. However, the centromeric Haspin-H3T3ph-CPC pathway remains largely uncharacterized in mammalian male meiosis. We have analyzed Haspin functions by either its chemical inhibition in cultured spermatocytes using LDN-192960, or the ablation of Haspin gene in Haspin-/-. Our studies suggest that Haspin kinase activity is required for proper chromosome congression during both meiotic divisions and for the recruitment of Aurora B and kinesin MCAK to meiotic centromeres. However, the absence of H3T3ph histone mark does not alter Borealin and SGO2 centromeric localization. These results add new and relevant information regarding the regulation of the Haspin-H3T3ph-CPC pathway and centromere function during meiosis.

CPEB1 directs muscle stem cell activation by reprogramming the translational landscape

Skeletal muscle stem cells, also called Satellite Cells (SCs), are actively maintained in quiescence but can activate quickly upon extrinsic stimuli. However, the mechanisms of how quiescent SCs (QSCs) activate swiftly remain elusive. Here, using a whole mouse perfusion fixation approach to obtain bona fide QSCs, we identify massive proteomic changes during the quiescence-to-activation transition in pathways such as chromatin maintenance, metabolism, transcription, and translation. Discordant correlation of transcriptomic and proteomic changes reveals potential translational regulation upon SC activation. Importantly, we show Cytoplasmic Polyadenylation Element Binding protein 1 (CPEB1), post-transcriptionally affects protein translation during SC activation by binding to the 3' UTRs of different transcripts. We demonstrate phosphorylation-dependent CPEB1 promoted Myod1 protein synthesis by binding to the cytoplasmic polyadenylation elements (CPEs) within its 3' UTRs to regulate SC activation and muscle regeneration. Our study characterizes CPEB1 as a key regulator to reprogram the translational landscape directing SC activation and subsequent proliferation.

Centrosomal-associated Proteins: Potential therapeutic targets for solid tumors?

The centrosome is a special organelle in human cells and an organizing unit for microtubules and signaling molecules. In addition, the centrosome is tightly restricted during the cell cycle and forms the basal body of the cilia in ciliated cells. Centrosome abnormality is frequently observed in malignant tumors. The dysregulation of centrosome-associated proteins leads to multipolar mitosis, aneuploidy, and nondirected cell migration, and therefore promotes cancer progression. The overduplication of primary centrosome and the accumulation of chromosome, comprise the majority cause of chromosomal mis-segregation in cancer cells. This review discusses the structure and function of the centrosome and the role of its associated proteins in the progression of solid tumors. We summarized the effects of centrosome amplification abnormalities and other centrosome-related phenotypes on tumors. The mechanism of the delineation of centrosome amplification with tumor malignancy remains to be decided. A better understanding of centrosome abnormality in tumorigenesis may be useful to screen novel therapeutic strategies for the treatment of solid tumors.

PLK1 regulates centrosome migration and spindle dynamics in male mouse meiosis

Cell division requires the regulation of karyokinesis and cytokinesis, which includes an essential role of the achromatic spindle. Although the functions of centrosomes are well characterised in somatic cells, their role during vertebrate spermatogenesis remains elusive. We have studied the dynamics of the meiotic centrosomes in male mouse during both meiotic divisions. Results show that meiotic centrosomes duplicate twice: first duplication occurs in the leptotene/zygotene transition, while the second occurs in interkinesis. The maturation of duplicated centrosomes during the early stages of prophase I and II are followed by their separation and migration to opposite poles to form bipolar spindles I and II. The study of the genetic mouse model Plk1(Δ/Δ) indicates a central role of Polo-like kinase 1 in pericentriolar matrix assembly, in centrosome maturation and migration, and in the formation of the bipolar spindles during spermatogenesis. In addition, in vitro inhibition of Polo-like kinase 1 and Aurora A in organotypic cultures of seminiferous tubules points out to a prominent role of both kinases in the regulation of the formation of meiotic bipolar spindles.

The Function of BARD1 in Centrosome Regulation in Cooperation with BRCA1/OLA1/RACK1

Breast cancer gene 1 (BRCA1)-associated RING domain protein 1 (BARD1) forms a heterodimer with BRCA1, a tumor suppressor associated with hereditary breast and ovarian cancer. BRCA1/BARD1 functions in multiple cellular processes including DNA repair and centrosome regulation. Centrosomes are the major microtubule-organizing centers in animal cells and are critical for the formation of a bipolar mitotic spindle. BRCA1 and BARD1 localize to the centrosome during the cell cycle, and the BRCA1/BARD1 dimer ubiquitinates centrosomal proteins to regulate centrosome function. We identified Obg-like ATPase 1 (OLA1) and receptor for activated C kinase (RACK1) as BRCA1/BARD1-interating proteins that bind to BARD1 and BRCA1 and localize the centrosomes during the cell cycle. Cancer-derived variants of BRCA1, BARD1, OLA1, and RACK1 failed to interact, and aberrant expression of these proteins caused centrosome amplification due to centriole overduplication only in mammary tissue-derived cells. In S-G2 phase, the number of centrioles was higher in mammary tissue-derived cells than in cells from other tissues, suggesting their involvement in tissue-specific carcinogenesis by BRCA1 and BARD1 germline mutations. We described the function of BARD1 in centrosome regulation in cooperation with BRCA1/OLA1/RACK1, as well as the effect of their dysfunction on carcinogenesis.

Identification of lung adenocarcinoma biomarkers based on bioinformatic analysis and human samples

Lung adenocarcinoma is one of the most common malignant tumors worldwide. Although efforts have been made to clarify its pathology, the underlying molecular mechanisms of lung adenocarcinoma are still not clear. The microarray datasets GSE75037, GSE63459 and GSE32863 were downloaded from the Gene Expression Omnibus (GEO) database to identify biomarkers for effective lung adenocarcinoma diagnosis and therapy. The differentially expressed genes (DEGs) were identified by GEO2R, and function enrichment analyses were conducted using the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO). The STRING database and Cytoscape software were used to construct and analyze the protein-protein interaction network (PPI). We identified 376 DEGs, consisting of 83 upregulated genes and 293 downregulated genes. Functional and pathway enrichment showed that the DEGs were mainly focused on regulation of cell proliferation, the transforming growth factor β receptor signaling pathway, cell adhesion, biological adhesion, and responses to hormone stimulus. Sixteen hub genes were identified and biological process analysis showed that these 16 hub genes were mainly involved in the M phase, cell cycle phases, the mitotic cell cycle, and nuclear division. We further confirmed the two genes with the highest node degree, DNA topoisomerase IIα (TOP2A) and aurora kinase A (AURKA), in lung adenocarcinoma cell lines and human samples. Both these genes were upregulated and associated with larger tumor size. Upregulation of AURKA in particular, was associated with lymphatic metastasis. In summary, identification of the DEGs and hub genes in our research enables us to elaborate the molecular mechanisms underlying the genesis and progression of lung adenocarcinoma and identify potential targets for the diagnosis and treatment of lung adenocarcinoma.

E3 Ubiquitin Ligase TRIM Proteins, Cell Cycle and Mitosis

The cell cycle is a series of events by which cellular components are accurately segregated into daughter cells, principally controlled by the oscillating activities of cyclin-dependent kinases (CDKs) and their co-activators. In eukaryotes, DNA replication is confined to a discrete synthesis phase while chromosome segregation occurs during mitosis. During mitosis, the chromosomes are pulled into each of the two daughter cells by the coordination of spindle microtubules, kinetochores, centromeres, and chromatin. These four functional units tie chromosomes to the microtubules, send signals to the cells when the attachment is completed and the division can proceed, and withstand the force generated by pulling the chromosomes to either daughter cell. Protein ubiquitination is a post-translational modification that plays a central role in cellular homeostasis. E3 ubiquitin ligases mediate the transfer of ubiquitin to substrate proteins determining their fate. One of the largest subfamilies of E3 ubiquitin ligases is the family of the tripartite motif (TRIM) proteins, whose dysregulation is associated with a variety of cellular processes and directly involved in human diseases and cancer. In this review we summarize the current knowledge and emerging concepts about TRIMs and their contribution to the correct regulation of cell cycle, describing how TRIMs control the cell cycle transition phases and their involvement in the different functional units of the mitotic process, along with implications in cancer progression.

Protein Kinase D2 Modulates Cell Cycle By Stabilizing Aurora A Kinase at Centrosomes

Aurora A kinase (AURKA) is a master cell-cycle regulator that is often dysregulated in human cancers. Its overexpression has been associated with genome instability and oncogenic transformation. The protein kinase D (PKD) family is an emerging therapeutic target of cancer. Aberrant PKD activation has been implicated in tumor growth and survival, yet the underlying mechanisms remain to be elucidated. This study identified, for the first time, a functional crosstalk between PKD2 and Aurora A kinase in cancer cells. The data demonstrate that PKD2 is catalytically active during the G₂-M phases of the cell cycle, and inactivation or depletion of PKD2 causes delay in mitotic entry due to downregulation of Aurora A, an effect that can be rescued by overexpression of Aurora A. Moreover, PKD2 localizes in the centrosome with Aurora A by binding to γ-tubulin. Knockdown of PKD2 caused defects in centrosome separation, elongated G₂ phase, mitotic catastrophe, and eventually cell death via apoptosis. Mechanistically, PKD2 interferes with Fbxw7 function to protect Aurora A from ubiquitin- and proteasome-dependent degradation. Taken together, these results identify PKD as a cell-cycle checkpoint kinase that positively modulates G₂-M transition through Aurora A kinase in mammalian cells.Implications: PKD2 is a novel cell-cycle regulator that promotes G₂-M transition by modulating Aurora A kinase stability in cancer cells and suggests the PKD2/Aurora A kinase regulatory axis as new therapeutic targets for cancer treatment. Mol Cancer Res; 16(11); 1785-97. ©2018 AACR.

Dynamics of human protein kinase Aurora A linked to drug selectivity

Protein kinases are major drug targets, but the development of highly-selective inhibitors has been challenging due to the similarity of their active sites. The observation of distinct structural states of the fully-conserved Asp-Phe-Gly (DFG) loop has put the concept of conformational selection for the DFG-state at the center of kinase drug discovery. Recently, it was shown that Gleevec selectivity for the Tyr-kinase Abl was instead rooted in conformational changes after drug binding. Here, we investigate whether protein dynamics after binding is a more general paradigm for drug selectivity by characterizing the binding of several approved drugs to the Ser/Thr-kinase Aurora A. Using a combination of biophysical techniques, we propose a universal drug-binding mechanism, that rationalizes selectivity, affinity and long on-target residence time for kinase inhibitors. These new concepts, where protein dynamics in the drug-bound state plays the crucial role, can be applied to inhibitor design of targets outside the kinome.

Protein kinases are a family of enzymes found in all living organisms. These enzymes help to control many biological processes, including cell division. When particular protein kinases do not work correctly, cells may start to divide uncontrollably, which can lead to cancer. One example is the kinase Aurora A, which is over-active in many common human cancers. As a result, researchers are currently trying to design drugs that reduce the activity of Aurora A in the hope that these could form new anticancer treatments.

In general, drugs are designed to be as specific in their action as possible to reduce the risk of harmful side effects to the patient. Designing a drug that affects a single protein kinase, however, is difficult because there are hundreds of different kinases in the body, all with similar structures. Because drugs often work by binding to specific structural features, a drug that targets one protein kinase can often alter the activity of a large number of others too.

Gleevec is a successful anti-leukemia drug that specifically works on one target kinase, producing minimal side effects. It was recently discovered that the drug works through a phenomenon called ‘induced fit’. This means that after the drug binds it causes a change in the enzyme’s overall shape that alters the activity of the enzyme. The shape change is complex, and so even small structural differences can change the effect of a particular drug.

Do other drugs that target other protein kinases also produce induced fit effects? To find out, Pitsawong, Buosi, Otten, Agafonov et al. studied how three anti-cancer drugs interact with Aurora A: two drugs specifically designed to switch off Aurora A, and Gleevec (which does not target Aurora A).

The two drugs that specifically target Aurora A were thought to work by targeting one structural feature of the enzyme. However, the biochemical and biophysical experiments performed by Pitsawong et al. revealed that these drugs instead work through an induced fit effect. By contrast, Gleevec did not trigger an induced fit on Aurora A and so bound less tightly to it.

In light of these results, Pitsawong et al. suggest that future efforts to design drugs that target protein kinases should focus on exploiting the induced fit process. This will require more research into the structure of particular kinases.

Targeting hepatocarcinogenesis model in C56BL6 mice with pan-aurora kinase inhibitor Danusertib

Background: To elucidate the expression of Aurora kinases (AURK) and the anticancer effects of pan-aurora kinase inhibitor Danusertib in hepatocarcinogenesis model in C56Bl6 mice.

Methods: Thirty mice C56Bl6 were randomly divided into Group A or control, Group B animals who underwent experimental hepatocarcinogenesis with diethylnitrosamine (DEN), and Group C animals with DEN-induced hepatocarcinogenenesis that treated with pan-aurora kinase inhibitor Danusertib. Primary antibodies for immunochistochemistry (IHC) included rabbit antibodies against Ki-67, DKK1, INCENP, cleaved caspase-3, NF-κB p65, c-Jun, β-catenin. Hepatocyte growth factor receptor (C-MET/HGFR) and Bcl-2 antagonist of cell death (BAD) serum levels were determined using a quantitative sandwich enzyme immunoassay technique.

Results: Inhibition of AURK reduced the number of DEN-induced liver tumours. Apoptosis and proliferation was very low in both DEN-induced and anti- AURK groups respectively. The hepatocellular adenoma cells of DEN-treated mice uniformly had ample nuclear INCENP whereas in anti- AURK markedly decreased. Expression of β-catenin, NF-kB and c-Jun did not differ in liver tumors of both AURK -depleted and non-depleted mice.

Conclusions: Depletion of AURK reduced the number of DEN-induced hepatic tumours. However, their size did not differ significantly between the groups.

Amplified centrosomes and mitotic index display poor concordance between patient tumors and cultured cancer cells

Centrosome aberrations (CA) and abnormal mitoses are considered beacons of malignancy. Cancer cell doubling times in patient tumors are longer than in cultures, but differences in CA between tumors and cultured cells are uncharacterized. We compare mitoses and CA in patient tumors, xenografts, and tumor cell lines. We find that mitoses are rare in patient tumors compared with xenografts and cell lines. Contrastingly, CA is more extensive in patient tumors and xenografts (~35–50% cells) than cell lines (~5–15%), although CA declines in patient-derived tumor cells over time. Intratumoral hypoxia may explain elevated CA in vivo because exposure of cultured cells to hypoxia or mimicking hypoxia pharmacologically or genetically increases CA, and HIF-1α and hypoxic gene signature expression correlate with CA and centrosomal gene signature expression in breast tumors. These results highlight the importance of utilizing low-passage-number patient-derived cell lines in studying CA to more faithfully recapitulate in vivo cellular phenotypes.

Important molecular genetic markers of colorectal cancer

Colorectal cancer (CRC) ranks third in the incidences of cancer morbidity and mortality worldwide. CRC is rather heterogeneous with regard to molecular genetic characteristics and pathogenic pathways. A wide spectrum of biomarkers is used for molecular subtype determination, prognosis, and estimation of sensitivity to different drugs in practice. These biomarkers can include germline and somatic mutations, chromosomal aberrations, genomic abnormalities, gene expression alterations at mRNA or protein level and changes in DNA methylation status. In the present review we discuss the most important and well-studied CRC biomarkers, and their potential clinical significance and current approaches to molecular classification of colorectal tumors.

Aurora-A modulates MMP-2 expression via AKT/NF-κB pathway in esophageal squamous cell carcinoma cells

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignancies. It is necessary to identify new markers for predicting tumor progression and therapeutic molecular targets. It has been reported that overexpressions of Aurora-A and matrix metalloproteinases 2 (MMP-2) may promote the malignant development of tumor. However, the relationship between Aurora-A and MMP-2 expression in tumor patients has not been investigated. In addition, the underlying mechanisms that Aurora-A regulates MMP-2 expression are still not fully elucidated. In this study, we demonstrated that Aurora-A and MMP-2 were overexpressed in ESCC tissues compared with paired normal adjacent tissues (P < 0.0001). Overexpression of Aurora-A was associated with the lymph node metastasis of ESCC (P = 0.01). Significantly, Aurora-A protein expression was positively correlated with MMP-2 protein expression in ESCC tissues (r = 0.66, P < 0.0001) as well as in ESCC cell lines. The level of Aurora-A expression was also positively correlated with the invasion capability of ESCC cells. Furthermore, Aurora-A overexpression significantly increased ESCC cell invasion by the upregulation of MMP-2 expression. In addition, Aurora-A overexpression promoted nuclear factor-kappaB (NF-κB) activation, and Aurora-A-mediated MMP-2 upregulation was abrogated by NF-κB inhibitor. Further analysis showed that activation of NF-κB was severely attenuated by AKT inhibitor in cells overexpressing Aurora-A. Taken together, these data indicate that Aurora-A overexpression upregulates MMP-2 expression through activating AKT/NF-κB signaling pathway in ESCC cells. These findings reveal that Aurora-A may be used as an important indicator for the judgment of malignant behavior of ESCC, and may be an attractive target for cancer therapy.

Aurora A drives early signalling and vesicle dynamics during T-cell activation

Aurora A is a serine/threonine kinase that contributes to the progression of mitosis by inducing microtubule nucleation. Here we have identified an unexpected role for Aurora A kinase in antigen-driven T-cell activation. We find that Aurora A is phosphorylated at the immunological synapse (IS) during TCR-driven cell contact. Inhibition of Aurora A with pharmacological agents or genetic deletion in human or mouse T cells severely disrupts the dynamics of microtubules and CD3ζ-bearing vesicles at the IS. The absence of Aurora A activity also impairs the activation of early signalling molecules downstream of the TCR and the expression of IL-2, CD25 and CD69. Aurora A inhibition causes delocalized clustering of Lck at the IS and decreases phosphorylation levels of tyrosine kinase Lck, thus indicating Aurora A is required for maintaining Lck active. These findings implicate Aurora A in the propagation of the TCR activation signal.

Aurora A is a protein kinase that contributes to the progression of mitosis by stimulating microtubule nucleation. Here the authors show that Aurora A also functions during T cell activation by maintaining TCR signaling through Lck activation.

Aurora A inhibition by MNL8054 promotes centriole elongation during Drosophila male meiosis

Aurora A kinase plays an important role in several aspects of cell division, including centrosome maturation and separation, a crucial step for the correct organization of the bipolar spindle. Although it has long been showed that this kinase accumulates at the centrosome throughout mitosis its precise contribution to centriole biogenesis and structure has until now not been reported. It is not surprising that so little is known, due to the small size of somatic centrioles, where only dramatic structural changes may be identified by careful electron microscopy analysis. Conversely, centrioles of Drosophila primary spermatocytes increase tenfold in length during the first prophase, thus making any change easily detectable. Therefore, we examined the consequence of the pharmacological inhibition of Aurora A by MLN8054 on centriole biogenesis during early Drosophila gametogenesis. Here, we show that depletion of this kinase results in longer centrioles, mainly during transition from prophase to prometaphase of the first meiosis. We also found abnormal ciliogenesis characterized by irregularly growing axonemal doublets. Our results represent the first documentation of a potential requirement of Aurora A in centriole integrity and elongation.

Proteins of the mitotic checkpoint and spindle are related to chromosomal instability and unfavourable prognosis in patients with myelodysplastic syndrome

AIMS

To study the immunoexpression of proteins related to the mitotic checkpoint (cell division cycle 20 (CDC20), mitotic arrest deficient 2 (MAD2)) and the mitotic spindle (Aurora-B) in patients with myelodysplastic syndrome (MDS).

METHODS

Protein expression was analysed in bone marrow tissue samples from 40 patients with MDS using immunohistochemistry. Prognostic markers (transfusion dependency, depth of cytopenias, chromosomal abnormalities and survival) were also studied.

RESULTS

Higher MAD2 expression was observed among patients with platelets <50×10(9)/L than among patients with platelets ≥50×10(9)/L (42.6±22.8% vs 22.7±19.1%, respectively). Higher CDC20 expression was identified among patients with three dysplasias compared with patients who presented with one or two dysplasias (33.9±24.1% vs 10.5±5.7% vs 12.8±7.8%, respectively), among patients who exhibited a complex versus non-complex karyotype (50.0±30.2% vs 18.4±14%, respectively) and among patients with platelets <50×10(9)/L vs platelets ≥50×10(9)/L (38.2±26.2% vs 16.1±12.4%, respectively). Higher Aurora-B expression was found in patients with an abnormal versus normal karyotype (21.2±13.2% vs 7.5±5.0%, respectively). High expression of MAD2 and CDC20 (≥50%) was associated with severe thrombocytopenia. We also found statistically significant differences in the overall survival rate when comparing different degrees of CDC20, MAD2 and Aurora-B protein expression.

CONCLUSIONS

To the best of our knowledge, this is the first report to demonstrate that these proteins are associated with chromosomal abnormalities and poor prognosis in patients with MDS.

Genetic variation in cell cycle regulatory gene AURKA and association with intrinsic breast cancer subtype

AURKA is a putative low-penetrance tumor susceptibility gene due to its prominent role in cell cycle regulation and centrosomal function. Germline variation in AURKA was evaluated for association with breast cancer and intrinsic breast cancer subtypes in the Carolina Breast Cancer Study (CBCS), a population-based case-control study of African Americans (AA) and Caucasians (Cau). Tag and candidate single nucleotide polymorphisms (SNPs) on AURKA were genotyped in 1946 cases and 1747 controls. In race-stratified analyses adjusted for age and African ancestry, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate SNP associations with breast cancer. In a race-combined analysis with similar adjustment, these associations were also examined by intrinsic breast cancer subtype. Using dominant models, most AURKA SNPs demonstrated no association with breast cancer in the race-stratified analyses. Among AA, rs6092309 showed an inverse association with breast cancer (OR = 0.69, 95% CI = 0.53-0.90). In the race-combined analyses, rs6099128 had reduced ORs for luminal A (OR = 0.76, 95% CI = 0.60-0.95) and basal-like breast cancer (OR = 0.54, 95% CI = 0.37-0.80). Rs6092309 showed a similar pattern of association with each subtype. Three SNPs (rs6014711, rs911162, rs1047972) had positive associations with basal-like breast cancer, and ORs reduced or close to 1.00 for other subtypes. Our results suggest inverse associations between some AURKA SNPs and overall breast cancer in AA. We found differential associations by specific subtypes and by race. Replication of these findings in larger AA populations would allow more powerful race-stratified subtype analyses.

Association between genetic polymorphisms in AURKA (rs2273535 and rs1047972) and breast cancer risk: a meta-analysis involving 37,221 subjects

Background

Published data on the association between AURKA polymorphisms and breast cancer (BC) risk are inconclusive. This meta-analysis was performed to derive a more precise estimation on the relationship between AURKA polymorphisms (rs2273535 and rs1047972) and BC risk.

Methods

PubMed, Web of Knowledge and Embase were searched for relevant studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the strength of associations. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were performed for allele contrast genetic model, homozygous genetic model, heterozygote genetic model, dominant model, and recessive model, respectively.

Results

A total of 13 studies (16,349 BC patients and 20,872 case-free controls) were involved in this meta-analysis. Meta-analysis showed that there was significant association between rs2273535 and BC risk in three genetic models in the overall population (A vs. T: OR = 1.08, 95% CI = 1.01–1.15, P = 0.02; AA vs. TT: OR = 1.36, 95% CI = 1.06-1.73, P < 0.00001; AA vs. TT + TA: OR = 1.15, 95% CI = 1.01-1.31, P = 0.04). In the subgroup analysis by ethnicity, the effects remained in Asians (allele contrast genetic model: OR = 1.12, 95% CI = 1.00-1.26, P = 0.04 and homozygote comparison: OR = 1.22, 95% CI = 1.06-1.41, P = 0.007). However, no genetic models reached statistical association in Cauasians. Rs1047972 polymorphism was associated with BC risk in the overall population based on homozygote comparison (AA vs. GG: OR = 0.81, 95% CI = 0.66-0.99, P = 0.04). When stratified by ethnicity, rs1047972 polymorphism had a decreased association with BC risk in Caucasians based on allele contrast genetic model, homozygote comparison, the dominant model and the recessive model. However, there was no association in any genetic model in Asians.

Conclusions

This meta-analysis suggests that AURKA rs2273535 polymorphism has an increased risk with BC, especially in Asians. However, rs1047972 polymorphism has a decreased BC risk in Caucasians. Further large scale multicenter epidemiological studies are warranted to confirm this finding.

A new aurora in anaplastic thyroid cancer therapy

Anaplastic thyroid cancers (ATC) are among the most aggressive human neoplasms with a dire prognosis and a median survival time of few months from the diagnosis. The complete absence of effective therapies for ATC renders the identification of novel therapeutic approaches sorely needed. Chromosomal instability, a feature of all human cancers, is thought to represent a major driving force in thyroid cancer progression and a number of mitotic kinases showing a deregulated expression in malignant thyroid tissues are now held responsible for thyroid tumor aneuploidy. These include the three members of the Aurora family (Aurora-A, Aurora-B, and Aurora-C), serine/threonine kinases that regulate multiple aspects of chromosome segregation and cytokinesis. Over the last few years, several small molecule inhibitors targeting Aurora kinases were developed, which showed promising antitumor effects against a variety of human cancers, including ATC, in preclinical studies. Several of these molecules are now being evaluated in phase I/II clinical trials against advanced solid and hematological malignancies. In the present review we will describe the structure, expression, and mitotic functions of the Aurora kinases, their implications in human cancer progression, with particular regard to ATC, and the effects of their functional inhibition on malignant cell proliferation.

Low concentration of arsenic-induced aberrant mitosis in keratinocytes through E2F1 transcriptionally regulated Aurora-A

Chronic exposure to low-concentration arsenic promotes cell proliferation and carcinogenesis both in vitro and in vivo. Centrosome amplification, the major cause of chromosome instability, occurs frequently in cancers. Aurora-A is a mitotic kinase and causes centrosome amplification and chromosome instability when overexpressed. Our previous study revealed that low-concentration arsenic induces Aurora-A overexpression in immortalized bladder cells. In this study, we hypothesized that low-concentration arsenic induces aberrant mitosis in keratinocytes due to Aurora-A overexpression. The specimen of Bowen's disease (BD) and squamous cell carcinoma obtained from arseniasis-endemic areas in Taiwan showed Aurora-A overexpression. The mRNA/protein levels and kinase activity of Aurora-A were increased in immortalized keratinocyte HaCaT cells after arsenic treatment at low concentration (< 1µM). Aberrant spindles, multiple centrosomes, and multinucleated cells were detected under fluorescent microscopy in HaCaT cells after arsenic treatment. These findings were associated with increased expression of Aurora-A. We further revealed that Aurora-A was regulated by arsenic-induced transcriptional factor E2F1 as demonstrated by chromosome immunoprecipitation, promoter activity, and small interfering RNA assays. Finally, in arsenic-treated HaCaT cells and in BD, a significant increase of dysfunctional p53 was found, and this event correlated with the increase in expression of Aurora-A. Altogether, our data suggest that low concentration of arsenic induces activation of E2F1-Aurora-A axis and results in aberrant mitosis of keratinocytes. Overexpression of Aurora-A and dysfunctional p53 may act synergistically to trigger skin tumor formation. Our findings suggest that Aurora-A may be a potential target for the prevention and treatment of arsenic-related cancers.

Mitotic failures in cancer: Aurora B kinase and its potential role in the development of aneuploidy

One of the basic requirements during the process of cell division is to maintain genetic integrity and ensure normal ploidy. The family of Aurora kinases, composed of Aurora A, B and C, takes a major role in the control of centrosome cycle, mitotic entry, chromosome condensation and coordination of chromosomal movements. Deregulation of kinase expression was described in a series of different malignancies which was also associated with aneuploidy. Recently, Aurora kinases gained significant interest as potential therapeutic targets in oncology. While there is increasing evidence about the activities of Aurora A kinase during cancer progression, data are controversial regarding the role of Aurora B. In this review the biology of Aurora kinases and its potential relation to cancer progression is discussed with special focus on functional changes and determination of Aurora B kinase.

Shugoshins function as a guardian for chromosomal stability in nuclear division

Accurate chromosome segregation during mitosis and meiosis is regulated and secured by several distinctly different yet intricately connected regulatory mechanisms. As chromosomal instability is a hallmark of a majority of tumors as well as a cause of infertility for germ cells, extensive research in the past has focused on the identification and characterization of molecular components that are crucial for faithful chromosome segregation during cell division. Shugoshins, including Sgo1 and Sgo2, are evolutionarily conserved proteins that function to protect sister chromatid cohesion, thus ensuring chromosomal stability during mitosis and meiosis in eukaryotes. Recent studies reveal that Shugoshins in higher animals play an essential role not only in protecting centromeric cohesion of sister chromatids and assisting bi-orientation attachment at the kinetochores, but also in safeguarding centriole cohesion/engagement during early mitosis. Many molecular components have been identified that play essential roles in modulating/mediating Sgo functions. This review primarily summarizes recent advances on the mechanisms of action of Shugoshins in suppressing chromosomal instability during nuclear division in eukaryotic organisms.

Induction of robust de novo centrosome amplification, high-grade spindle multipolarity and metaphase catastrophe: a novel chemotherapeutic approach

Centrosome amplification (CA) and resultant chromosomal instability have long been associated with tumorigenesis. However, exacerbation of CA and relentless centrosome declustering engender robust spindle multipolarity (SM) during mitosis and may induce cell death. Recently, we demonstrated that a noscapinoid member, reduced bromonoscapine, (S)-3-(R)-9-bromo-5-(4,5-dimethoxy-1,3-dihydroisobenzofuran-1-yl)-4-methoxy-6-methyl-5,6,7,8-tetrahydro-[1,3]dioxolo-[4,5-g]isoquinoline (Red-Br-nos), induces reactive oxygen species (ROS)-mediated autophagy and caspase-independent death in prostate cancer PC-3 cells. Herein, we show that Red-Br-nos induces ROS-dependent DNA damage that resulted in high-grade CA and SM in PC-3 cells. Unlike doxorubicin, which causes double-stranded DNA breaks and chronic G2 arrest accompanied by ‘templated' CA, Red-Br-nos-mediated DNA damage elicits de novo CA during a transient S/G2 stall, followed by checkpoint abrogation and mitotic entry to form aberrant mitotic figures with supernumerary spindle poles. Attenuation of multipolar phenotype in the presence of tiron, a ROS inhibitor, indicated that ROS-mediated DNA damage was partly responsible for driving CA and SM. Although a few cells (∼5%) yielded to aberrant cytokinesis following an ‘anaphase catastrophe', most mitotically arrested cells (∼70%) succumbed to ‘metaphase catastrophe,' which was caspase-independent. This report is the first documentation of rapid de novo centrosome formation in the presence of parent centrosome by a noscapinoid family member, which triggers death-inducing SM via a unique mechanism that distinguishes it from other ROS-inducers, conventional DNA-damaging agents, as well as other microtubule-binding drugs.

Let's huddle to prevent a muddle: centrosome declustering as an attractive anticancer strategy

Nearly a century ago, cell biologists postulated that the chromosomal aberrations blighting cancer cells might be caused by a mysterious organelle-the centrosome-that had only just been discovered. For years, however, this enigmatic structure was neglected in oncologic investigations and has only recently reemerged as a key suspect in tumorigenesis. A majority of cancer cells, unlike healthy cells, possess an amplified centrosome complement, which they manage to coalesce neatly at two spindle poles during mitosis. This clustering mechanism permits the cell to form a pseudo-bipolar mitotic spindle for segregation of sister chromatids. On rare occasions this mechanism fails, resulting in declustered centrosomes and the assembly of a multipolar spindle. Spindle multipolarity consigns the cell to an almost certain fate of mitotic arrest or death. The catastrophic nature of multipolarity has attracted efforts to develop drugs that can induce declustering in cancer cells. Such chemotherapeutics would theoretically spare healthy cells, whose normal centrosome complement should preclude multipolar spindle formation. In search of the 'Holy Grail' of nontoxic, cancer cell-selective, and superiorly efficacious chemotherapy, research is underway to elucidate the underpinnings of centrosome clustering mechanisms. Here, we detail the progress made towards that end, highlighting seminal work and suggesting directions for future research, aimed at demystifying this riddling cellular tactic and exploiting it for chemotherapeutic purposes. We also propose a model to highlight the integral role of microtubule dynamicity and the delicate balance of forces on which cancer cells rely for effective centrosome clustering. Finally, we provide insights regarding how perturbation of this balance may pave an inroad for inducing lethal centrosome dispersal and death selectively in cancer cells.

The Aurora kinase Ipl1 is necessary for spindle pole body cohesion during budding yeast meiosis

In budding yeast, the microtubule-organizing center is called the spindle pole body (SPB) and shares structural components with the centriole, the central core of the animal centrosome. During meiotic interphase I, the SPB is duplicated when DNA replication takes place. Duplicated SPBs are linked and then separate to form a bipolar spindle required for homolog separation in meiosis I. During interphase II, SPBs are duplicated again, in the absence of DNA replication, to form four SPBs that establish two spindles for sister-chromatid separation in meiosis II. Here, we report that the Aurora kinase Ipl1, which is necessary for sister-chromatid cohesion, is also required for maintenance of a tight association between duplicated SPBs during meiosis, which we term SPB cohesion. Premature loss of cohesion leads to SPB overduplication and the formation of multipolar spindles. By contrast, the Polo-like kinase Cdc5 is necessary for SPB duplication and interacts antagonistically with Ipl1 at the meiotic SPB to ensure proper SPB separation. Our data suggest that Ipl1 coordinates SPB dynamics with the two chromosome segregation cycles during yeast meiosis.

TF--a novel cell-permeable and selective inhibitor of human protein kinase CK2 induces apoptosis in the prostate cancer cell line LNCaP

BACKGROUND

Abnormally high activity of protein kinase CK2 is linked to various diseases including cancer. Therefore, the inhibition of CK2 is a promising therapeutic strategy to fight this disease.

METHODS

We screened a library of synthetic molecules concerning their capacity to inhibit CK2. The activity of CK2 and their IC50 and Ki values were determined by a capillary electrophoresis assay. The effects of the inhibitor in a cell culture model were analyzed by cell counting, a viability assay, cytofluorimetry and Western blot.

RESULTS

The best CK2 inhibitor found in this screen was 6,7-dichloro-1,4-dihydro-8-hydroxy-4-[(4-methylphenylamino)methylen]dibenzo [b,d]furan-3(2H)-one, which we refer to as "TF". TF showed tight binding to CK2 with low IC50 (29 nM) and Ki (15 nM) values. TF inhibited only seven out of 61 human kinases tested (>70% inhibition). Incubation of LNCaP cells with 50 μM TF for 48 h decreased the intracellular CK2 activity by 50%, confirming that the inhibitor is membrane permeable. The decrease in activity was correlated with a severe reduction in cell viability. The reduction in cell viability is at least partly due to the induction of apoptosis.

GENERAL SIGNIFICANCE

In many cancers the protein kinase CK2 is significantly up-regulated and supports the neoplastic phenotype. New therapeutic strategies should be based on diverse reliable inhibitors to reverse the abnormal high levels to normal settings.

G Protein-coupled receptor kinase 5 is localized to centrosomes and regulates cell cycle progression

G protein-coupled receptor kinases (GRKs) are important regulators of G protein-coupled receptor function and mediate receptor desensitization, internalization, and signaling. While GRKs also interact with and/or phosphorylate many other proteins and modify their function, relatively little is known about the cellular localization of endogenous GRKs. Here we report that GRK5 co-localizes with γ-tubulin, centrin, and pericentrin in centrosomes. The centrosomal localization of GRK5 is observed predominantly at interphase and although its localization is not dependent on microtubules, it can mediate microtubule nucleation of centrosomes. Knockdown of GRK5 expression leads to G2/M arrest, characterized by a prolonged G2 phase, which can be rescued by expression of wild type but not catalytically inactive GRK5. This G2/M arrest appears to be due to increased expression of p53, reduced activity of aurora A kinase and a subsequent delay in the activation of polo-like kinase 1. Overall, these studies demonstrate that GRK5 is localized in the centrosome and regulates microtubule nucleation and normal cell cycle progression.

Epithelial cell polarity, stem cells and cancer

After years of extensive scientific discovery much has been learned about the networks that regulate epithelial homeostasis. Loss of expression or functional activity of cell adhesion and cell polarity proteins (including the PAR, crumbs (CRB) and scribble (SCRIB) complexes) is intricately related to advanced stages of tumour progression and invasiveness. But the key roles of these proteins in crosstalk with the Hippo and liver kinase B1 (LKB1)-AMPK pathways and in epithelial function and proliferation indicate that they may also be associated with the early stages of tumorigenesis. For example, deregulation of adhesion and polarity proteins can cause misoriented cell divisions and increased self-renewal of adult epithelial stem cells. In this Review, we highlight some advances in the understanding of how loss of epithelial cell polarity contributes to tumorigenesis.

Aurora-A inactivation causes mitotic spindle pole fragmentation by unbalancing microtubule-generated forces

BACKGROUND

Aurora-A is an oncogenic kinase playing well-documented roles in mitotic spindle organisation. We previously found that Aurora-A inactivation yields the formation of spindles with fragmented poles that can drive chromosome mis-segregation. Here we have addressed the mechanism through which Aurora-A activity regulates the structure and cohesion of spindle poles.

RESULTS

We inactivated Aurora-A in human U2OS osteosarcoma cells either by RNA-interference-mediated silencing or treating cultures with the specific inhibitor MLN8237. We show that mitotic spindle pole fragmentation induced by Aurora-A inactivation is associated with microtubule hyperstabilisation. Silencing of the microtubule-stabilising factor ch-TOG prevents spindle pole fragmentation caused by inactivation of Aurora-A alone and concomitantly reduces the hyperstabilisation of microtubules. Furthermore, decreasing pole-directed spindle forces by inhibition of the Eg5 kinesin, or by destabilisation of microtubule-kinetochore attachments, also prevents pole fragmentation in Aurora-A-inactivated mitoses.

CONCLUSIONS

Our findings indicate that microtubule-generated forces are imbalanced in Aurora-A-defective cells and exert abnormal pressure at the level of spindle poles, ultimately causing their fragmentation. This study therefore highlights a novel role of the Aurora-A kinase in regulating the balance between microtubule forces during bipolar spindle assembly.

Aurora B kinase inhibitor AZD1152: determinants of action and ability to enhance chemotherapeutics effectiveness in pancreatic and colon cancer

Background:

AZD1152, the prodrug for AZD1152-hydroxyquinazoline pyrazol anilide (HQPA), is a selective inhibitor of Aurora B kinase activity. Preclinical evaluation of AZD1152 has been reported in several human cancer models. The potentiality of this compound in combination therapy warrants further investigation in solid tumours.

Experimental design:

This study explored the effects of AZD1152-HQPA in colon and pancreatic tumour cells. The antitumour properties of AZD1152, either as single agent or in combination with chemotherapeutics, were evaluated in each study model. The efficacy and the toxicity of AZD1152 alone and in combination with gemcitabine were validated in pancreatic tumour xenograft model.

Results:

AZD1152-HQPA treatment resulted in a dramatic increase of chromosome number, modification of cell cycle and induction of apoptosis. The most effective combination was that with chemotherapeutics given soon after AZD1152 in both tumour cell types. The effectiveness of the sequential schedule of AZD1152 with gemcitabine was confirmed in nude mice bearing MiaPaCa-2 tumours, showing inhibition of tumour volumes and delaying of tumour growth after the interruption of the treatments.

Conclusion:

Here we show that AZD1152-HQPA enhances oxaliplatin and gemcitabine effectiveness in colon and pancreatic cancer, respectively. First, we provide advances into administration schedules and dosing regimens for the combination treatment in in vivo pancreatic tumour.

Downregulation of survivin and aurora A by histone deacetylase and RAS inhibitors: a new drug combination for cancer therapy

Histone deacetylase (HDAC) inhibitors, such as valproic acid (VPA), constitute a novel class of anticancer agents that cause an increase in acetylated histones and thus restore the expression of dormant tumor-suppressor and other genes related to cell differentiation, cell-cycle arrest or apoptosis of tumor cells. The Ras inhibitor farnesylthiosalicylic acid (FTS, salirasib) attenuates cancer cell proliferation in vitro and in vivo and, under certain circumstances, induces cell death. FTS by itself does not induce differentiation or complete growth arrest. The abovementioned activity of VPA as a differentiation agent suggested that it might be worth investigating its possible therapeutic potential in synergistic combination with FTS. Here, we examined whether the combined application of VPA and FTS could synergistically inhibit the proliferation of cancer cells that express oncogenic K-Ras (A549 nonsmall-cell lung carcinoma cells), DLD1 (colon carcinoma cells) or chronically active wild-type K-Ras and constitutively active B-Raf (ARO, thyroid carcinoma cells). The results showed that combined treatment with VPA and FTS synergistically reduces proliferation in all of these cancer cell lines by downregulating Ras and blocking the expression of Survivin and Aurora A. These alterations, which were most pronounced following the combined treatment, led to a mitotic crisis, as reflected by mislocalization of the chromosomal passenger complex. Our findings thus demonstrate that combination therapy with VPA and FTS might offer a promising therapeutic approach to the treatment of epithelial tumors.

A novel role for progesterone and progesterone receptor membrane component 1 in regulating spindle microtubule stability during rat and human ovarian cell mitosis

The present studies were designed to assess the roles of progesterone (P4) and Progesterone Receptor Membrane Component 1 (PGRMC1) in regulating mitosis of spontaneously immortalized granulosa cells (SIGCs) and ovarian cancer cells, SKOV-3 cells. Because PGRMC1 has been detected among the proteins of the human mitotic spindle, we theorized that P4 and PGRMC1 could affect mitosis through a microtubule-dependent process. The present study confirms that SIGC growth is slowed by either P4 treatment or transfection of a PGRMC1 antibody. In both cases, slower cell proliferation was accompanied by an increased percentage of mitotic cells, which is consistent with a P4-induced prolongation of the M phase of the cell cycle. In addition, P4 increased the stability of the spindle microtubules, as assessed by the rate of beta-tubulin disassembly in response to cooling. Also, P4 increased spindle microtubule stability of SKOV-3 cells. This effect was mimicked by the depletion of PGRMC1 in these cells. Importantly, P4 did not increase the stability of the microtubules over that observed in PGRMC1-depleted SKOV-3 cells. Immunofluorescent analysis revealed that PGRMC1 is distributed to the spindle apparatus as well as to the centrosomes at metaphase. Further in situ proximity ligation assay revealed that PGRMC1 interacted with beta-tubulin. Taken together, these results suggest that P4 inhibits mitosis of ovarian cells by increasing the stability of the mitotic spindle. Moreover, P4's actions appear to be dependent on PGRMC1's function within the mitotic spindle.

A novel microtubule-modulating noscapinoid triggers apoptosis by inducing spindle multipolarity via centrosome amplification and declustering

We have previously shown that a non-toxic noscapinoid, EM011 binds tubulin without altering its monomer/polymer ratio. EM011 is more active than the parent molecule, noscapine, in inducing G2/M arrest, inhibiting cellular proliferation and tumor growth in various human xenograft models. However, the mechanisms of mitotic-block and subsequent cell death have remained elusive. Here, we show that EM011-induced attenuation of microtubule dynamics was associated with impaired association of microtubule plus-end tracking proteins, such as EB1 and CLIP-170. EM011 treatment then led to the formation of multipolar spindles containing 'real' centrioles indicating drug-induced centrosome amplification and persistent centrosome declustering. Centrosome amplification was accompanied by an upregulation of Aurora A and Plk4 protein levels, as well as a surge in the kinase activity of Aurora A, suggesting a deregulation of the centrosome duplication cycle. Cell-cycle phase-specific experiments showed that the 'cytotoxicity-window' of the drug encompasses the late S-G2 period. Drug-treatment, excluding S-phase, not only resulted in lower sub-G1 population but also attenuated centrosome amplification and spindle multipolarity, suggesting that drug-induced centrosome amplification is essential for maximal cell death. Subsequent to a robust mitotic arrest, EM011-treated cells displayed diverse cellular fates suggesting a high degree of intraline variation. Some 'apoptosis-evasive' cells underwent aberrant cytokinesis to generate rampant aneuploidy that perhaps contributed to drug-induced cell death. These data indicate that spindle multipolarity induction by means of centrosome amplification has an exciting chemotherapeutic potential that merits further investigation.

Identification of candidate growth promoting genes in ovarian cancer through integrated copy number and expression analysis

Ovarian cancer is a disease characterised by complex genomic rearrangements but the majority of the genes that are the target of these alterations remain unidentified. Cataloguing these target genes will provide useful insights into the disease etiology and may provide an opportunity to develop novel diagnostic and therapeutic interventions. High resolution genome wide copy number and matching expression data from 68 primary epithelial ovarian carcinomas of various histotypes was integrated to identify genes in regions of most frequent amplification with the strongest correlation with expression and copy number. Regions on chromosomes 3, 7, 8, and 20 were most frequently increased in copy number (>40% of samples). Within these regions, 703/1370 (51%) unique gene expression probesets were differentially expressed when samples with gain were compared to samples without gain. 30% of these differentially expressed probesets also showed a strong positive correlation (r≥0.6) between expression and copy number. We also identified 21 regions of high amplitude copy number gain, in which 32 known protein coding genes showed a strong positive correlation between expression and copy number. Overall, our data validates previously known ovarian cancer genes, such as ERBB2, and also identified novel potential drivers such as MYNN, PUF60 and TPX2.