Aurora-B overexpression is correlated with aneuploidy and poor prognosis in non-small cell lung cancer

AURKB as a Therapeutic Target and Key Driver of Liver Cancer Growth and Metastasis

Hepatocellular carcinoma (HCC) is a major cause of cancer-related deaths worldwide. Aurora kinase B (AURKB), a critical regulator of mitosis, has been implicated in cancer progression, though its precise role in HCC remains unclear. In this study, AURKB expression was found to be significantly elevated in HCC tissues and cell lines compared to controls, as validated by GEPIA and ENCORI databases. Functional assays revealed that AURKB knockdown reduced cell proliferation, invasion, and migration, while increasing apoptosis. Furthermore, suppression of AURKB affected epithelial-mesenchymal transition (EMT) markers, decreasing vimentin and N-cadherin levels and increasing E-cadherin expression. In vivo, a xenograft mouse model demonstrated that tumors derived from AURKB-silenced cells exhibited reduced growth and fewer lung metastases. Histological and immunohistochemical analyses showed lower levels of Ki-67, MMP-9, and EMT markers in these tumors, alongside increased E-cadherin. These findings highlight AURKB's critical role in promoting HCC progression, metastasis, and EMT regulation. Overexpression of AURKB was associated with poor prognosis, suggesting it could serve as a potential biomarker and therapeutic target for liver cancer. Overall, targeting AURKB may provide a novel approach to inhibit HCC growth and metastasis, improving patient outcomes.

Machine Learning-Assisted Drug Repurposing Framework for Discovery of Aurora Kinase B Inhibitors

Background: Aurora kinase B (AurB) is a pivotal regulator of mitosis, making it a compelling target for cancer therapy. Despite significant advances in protein kinase inhibitor development, there are currently no AurB inhibitors readily available for therapeutic use. Methods: This study introduces a machine learning-assisted drug repurposing framework integrating quantitative structure-activity relationship (QSAR) modeling, molecular fingerprints-based classification, molecular docking, and molecular dynamics (MD) simulations. Using this pipeline, we analyzed 4680 investigational and approved drugs from DrugBank database. Results: The machine learning models trained for drug repurposing showed satisfying performance and yielded the identification of saredutant, montelukast, and canertinib as potential AurB inhibitors. The candidates demonstrated strong binding energies, key molecular interactions with critical residues (e.g., Phe88, Glu161), and stable MD trajectories, particularly saredutant, a neurokinin-2 (NK2) antagonist. Conclusions: Beyond identifying potential AurB inhibitors, this study highlights an integrated methodology that can be applied to other challenging drug targets.

Design and synthesis of (E)-3-benzylideneindolin-2-one derivatives as potential allosteric inhibitors of Aurora A kinase

The mitotic kinase Aurora A, a pivotal regulator of the cell cycle, is overexpressed in various cancers and has emerged as one of the most promising targets for anticancer drug discovery. However, the lack of specificity and potential toxicity have impeded clinical trials involving orthosteric inhibitors. In this study, allosteric sites of Aurora A were predicted using the AlloReverse web server. Based on the non-ATP competitive inhibitor Tripolin A and molecular docking information targeting the desired allosteric site 3 of Aurora A, a series of (E)-3-benzylideneindolin-2-one derivatives were designed and synthesized. Compared to Tripolin A, our compounds AK09, AK34 and AK35 have stronger inhibitory effects and can be further investigated as potential allosteric inhibitors. Moreover, the compound AK34 with the strongest inhibitory activity (IC50 = 1.68 μM) has a high affinity for Aurora A (K D = 216 nM). According to the analysis of the structure-activity relationship of the compounds and the results of their molecular docking models, these compounds tend to act on the allosteric site 3 of Aurora A.

A comprehensive review on role of Aurora kinase inhibitors (AKIs) in cancer therapeutics

Aurora kinases (AURKs) are a family of serine /threonine protein kinases that have a crucial role in cell cycle process mainly in the event of chromosomal segregation, centrosome maturation and cytokinesis. The family consists of three members including Aurora kinase A (AURK-A), Aurora kinase B (AURK-B) and Aurora kinase C (AURK-C). All AURKs contain a conserved kinase domain for their activity but differ in their cellular localization and functions. AURK-A and AURK-B are expressed mainly in somatic cells while the expression of AURK-C is limited to germ cells. AURK-A promotes G2 to M transition of cell cycle by controlling centrosome maturation and mitotic spindle assembly. AURK-B and AURK-C form the chromosome passenger complex (CPC) that ensures proper chromosomal alignments and segregation. Aberrant expression of AURK-A and AURK-B has been detected in several solid tumours and malignancies. Hence, they have become an attractive therapeutic target against cancer. The first part of this review focuses on AURKs structure, functions, subcellular localization, and their role in tumorigenesis. The review also highlights the functional and clinical impact of selective as well as pan kinase inhibitors. Currently, >60 compounds that target AURKs are in preclinical and clinical studies. The drawbacks of existing inhibitors like selectivity, drug resistance and toxicity have also been addressed. Since, majority of inhibitors are Aurora kinase inhibitor (AKI) type-1 that bind to the active (DFGin and Cin) conformation of the kinase, this information may be utilized to design highly selective kinase inhibitors that can be combined with other therapeutic agents for better clinical outcomes.

Overexpression of Aurora Kinase B Is Correlated with Diagnosis and Poor Prognosis in Hepatocellular Carcinoma

Aurora kinase B (AURKB) overexpression promotes tumor initiation and development by participating in the cell cycle. In this study, we focused on the mechanism of AURKB in hepatocellular carcinoma (HCC) progression and on AURKB's value as a diagnostic and prognostic biomarker in HCC. We used data from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) to analyze AURKB expression in HCC. We found that the expression levels of AURKB in HCC samples were higher than those in the corresponding control group. R packages were used to analyze RNA sequencing data to identify AURKB-related differentially expressed genes (DEGs), and these genes were found to be significantly enriched during the cell cycle. The biological function of AURKB was verified, and the results showed that cell proliferation was slowed down and cells were arrested in the G2/M phase when AURKB was knocked down. AURKB overexpression resulted in significant differences in clinical symptoms, such as the clinical T stage and pathological stage. Kaplan-Meier survival analysis, Cox regression analysis, and Receiver Operating Characteristic (ROC) curve analysis suggested that AURKB overexpression has good diagnostic and prognostic potential in HCC. Therefore, AURKB may be used as a potential target for the diagnosis and cure of HCC.

Safety, tolerability, and pharmacokinetics of Aurora kinase B inhibitor AZD2811: a phase 1 dose-finding study in patients with advanced solid tumours

BACKGROUND

AZD2811 is a potent, selective Aurora kinase B inhibitor. We report the dose-escalation phase of a first-in-human study assessing nanoparticle-encapsulated AZD2811 in advanced solid tumours.

METHODS

AZD2811 was administered in 12 dose-escalation cohorts (2-h intravenous infusion; 15‒600 mg; 21-/28-day cycles) with granulocyte colony-stimulating factor (G-CSF) at higher doses. The primary objective was determining safety and maximum tolerated/recommended phase 2 dose (RP2D).

RESULTS

Fifty-one patients received AZD2811. Drug exposure was sustained for several days post-dose. The most common AZD2811-related adverse events (AEs) were fatigue (27.3%) at ≤200 mg/cycle and neutropenia (37.9%) at ≥400 mg/cycle. Five patients had dose-limiting toxicities: grade (G)4 decreased neutrophil count (n = 1, 200 mg; Days 1, 4; 28-day cycle); G4 decreased neutrophil count and G3 stomatitis (n = 1 each, both 400 mg; Day 1; 21-day cycle); G3 febrile neutropenia and G3 fatigue (n = 1 each, both 600 mg; Day 1; 21-day cycle +G-CSF). RP2D was 500 mg; Day 1; 21-day cycle with G-CSF on Day 8. Neutropenia/neutrophil count decrease were on-target AEs. Best overall responses were partial response (n = 1, 2.0%) and stable disease (n = 23, 45.1%).

CONCLUSIONS

At RP2D, AZD2811 was tolerable with G-CSF support. Neutropenia was a pharmacodynamic biomarker.

CLINICAL TRIAL REGISTRATION

NCT02579226.

DNA image cytometry ploidy analysis technique improves the detection rate of pleural effusion cytology

OBJECTIVE

To explore the clinical diagnostic value of DNA image cytometry (DNA-ICM) ploidy analysis in malignant pleural effusion cancer screening, this study analyzed the effect of exfoliated cell smears (ECSs), cell blocks (CBs), and immunochemistry.

METHOD

A total of 830 cases of pleural effusion were considered for the DNA-ICM ploidy analysis. The ECSs were centrifuged, the CBs were formed, and the DNA-ICM ploidy analysis was carried out in the diagnosis of malignant pleural effusion. Immunochemistry and biopsy was applied to differentiate between benign and malignant pleural effusion and to determine the source of the latter. The sensitivity and specificity differences between the three methods alone and in combination were compared.

RESULTS

The sensitivity of the DNA-ICM, ECS, and CB methods was 96.28%, 94.93%, and 95.95%, respectively, and the specificity of each method was 86.52%, 87.08%, and 86.14%, respectively. The sensitivity and specificity of the combined diagnosis method were 99.32% and 75.09%, respectively. Among the 22 cases diagnosed as positive in the DNA-ICM ploidy analysis but negative in the ECS and CB analyses, four cases were diagnosed as positive by comprehensive clinical diagnosis.

CONCLUSION

The sensitivity and specificity of DNA-ICM ploidy analysis are high; the positive detection rate of pleural fluid cytology is effectively increased, and the missed detection rate of cell pathologies is effectively reduced. The combination of the three methods significantly improves the specificity and sensitivity of the diagnosis of malignant pleural effusion, and immunochemistry with CBs can be used to accurately analyze the primary tumor site.

Drugging Hijacked Kinase Pathways in Pediatric Oncology: Opportunities and Current Scenario

Childhood cancer is considered rare, corresponding to ~3% of all malignant neoplasms in the human population. The World Health Organization (WHO) reports a universal occurrence of more than 15 cases per 100,000 inhabitants around the globe, and despite improvements in diagnosis, treatment and supportive care, one child dies of cancer every 3 min. Consequently, more efficient, selective and affordable therapeutics are still needed in order to improve outcomes and avoid long-term sequelae. Alterations in kinases' functionality is a trademark of cancer and the concept of exploiting them as drug targets has burgeoned in academia and in the pharmaceutical industry of the 21st century. Consequently, an increasing plethora of inhibitors has emerged. In the present study, the expression patterns of a selected group of kinases (including tyrosine receptors, members of the PI3K/AKT/mTOR and MAPK pathways, coordinators of cell cycle progression, and chromosome segregation) and their correlation with clinical outcomes in pediatric solid tumors were accessed through the R2: Genomics Analysis and Visualization Platform and by a thorough search of published literature. To further illustrate the importance of kinase dysregulation in the pathophysiology of pediatric cancer, we analyzed the vulnerability of different cancer cell lines against their inhibition through the Cancer Dependency Map portal, and performed a search for kinase-targeted compounds with approval and clinical applicability through the CanSAR knowledgebase. Finally, we provide a detailed literature review of a considerable set of small molecules that mitigate kinase activity under experimental testing and clinical trials for the treatment of pediatric tumors, while discuss critical challenges that must be overcome before translation into clinical options, including the absence of compounds designed specifically for childhood tumors which often show differential mutational burdens, intrinsic and acquired resistance, lack of selectivity and adverse effects on a growing organism.

Development of a peripheral blood transcriptomic gene signature to predict bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the most common lung disease of extreme prematurity, yet mechanisms that associate with or identify neonates with increased susceptibility for BPD are largely unknown. Combining artificial intelligence with gene expression data is a novel approach that may assist in better understanding mechanisms underpinning chronic lung disease and in stratifying patients at greater risk for BPD. The objective of this study is to develop an early peripheral blood transcriptomic signature that can predict preterm neonates at risk for developing BPD. Secondary analysis of whole blood microarray data from 97 very low birth weight neonates on day of life 5 was performed. BPD was defined as positive pressure ventilation or oxygen requirement at 28 days of age. Participants were randomly assigned to a training (70%) and testing cohort (30%). Four gene-centric machine learning models were built, and their discriminatory abilities were compared with gestational age or birth weight. This study adheres to the transparent reporting of a multivariable prediction model for individual prognosis or diagnosis (TRIPOD) statement. Neonates with BPD (n = 62 subjects) exhibited a lower median gestational age (26.0 wk vs. 30.0 wk, P < 0.01) and birth weight (800 g vs. 1,280 g, P < 0.01) compared with non-BPD neonates. From an initial pool (33,252 genes/patient), 4,523 genes exhibited a false discovery rate (FDR) <1%. The area under the receiver operating characteristic curve (AUC) for predicting BPD utilizing gestational age or birth weight was 87.8% and 87.2%, respectively. The machine learning models, using a combination of five genes, revealed AUCs ranging between 85.8% and 96.1%. Pathways integral to T cell development and differentiation were associated with BPD. A derived five-gene whole blood signature can accurately predict BPD in the first week of life.

Increased Aurora B expression reduces substrate phosphorylation and induces chromosomal instability

Increased Aurora B protein expression, which is common in cancers, is expected to increase Aurora B kinase activity, yielding elevated phosphorylation of Aurora B substrates. In contrast, here we show that elevated expression of Aurora B reduces phosphorylation of six different Aurora B substrates across three species and causes defects consistent with Aurora B inhibition. Complexes of Aurora B and its binding partner INCENP autophosphorylate in trans to achieve full Aurora B activation. Increased expression of Aurora B mislocalizes INCENP, reducing the local concentration of Aurora B:INCENP complexes at the inner centromere/kinetochore. Co-expression of INCENP rescues Aurora B kinase activity and mitotic defects caused by elevated Aurora B. However, INCENP expression is not elevated in concert with Aurora B in breast cancer, and increased expression of Aurora B causes resistance rather than hypersensitivity to Aurora B inhibitors. Thus, increased Aurora B expression reduces, rather than increases, Aurora B kinase activity.

Mitotic protein kinase-driven crosstalk of machineries for mitosis and metastasis

Accumulating evidence indicates that mitotic protein kinases are involved in metastatic migration as well as tumorigenesis. Protein kinases and cytoskeletal proteins play a role in the efficient release of metastatic cells from a tumor mass in the tumor microenvironment, in addition to playing roles in mitosis. Mitotic protein kinases, including Polo-like kinase 1 (PLK1) and Aurora kinases, have been shown to be involved in metastasis in addition to cell proliferation and tumorigenesis, depending on the phosphorylation status and cellular context. Although the genetic programs underlying mitosis and metastasis are different, the same protein kinases and cytoskeletal proteins can participate in both mitosis and cell migration/invasion, resulting in migratory tumors. Cytoskeletal remodeling supports several cellular events, including cell division, movement, and migration. Thus, understanding the contributions of cytoskeletal proteins to the processes of cell division and metastatic motility is crucial for developing efficient therapeutic tools to treat cancer metastases. Here, we identify mitotic kinases that function in cancer metastasis as well as tumorigenesis. Several mitotic kinases, namely, PLK1, Aurora kinases, Rho-associated protein kinase 1, and integrin-linked kinase, are considered in this review, as an understanding of the shared machineries between mitosis and metastasis could be helpful for developing new strategies to treat cancer.

Improving understanding of the mechanisms linking cell division and cancer spread (metastasis) could provide novel strategies for treatment. A group of enzymes involved in cell division (mitosis) are also thought to play critical roles in the spread of cancers. Hyungshin Yim at Hanyang University in Ansan, South Korea, and co-workers in Korea and the USA reviewed the roles of several mitotic enzymes that are connected with metastasis as well as tumorigenesis. They discussed how these enzymes modify cytoskeletal proteins and other substrates during cancer progression. Some regulatory control of cell cytoskeletal structures is required for cancer cells to metastasize. Recent research has uncovered crosstalk between mitotic enzymes and metastatic cytoskeletal molecules in various cancers. Targeting mitotic enzymes and the ways they influence cytoskeletal mechanisms could provide valuable therapeutic strategies for suppressing metastasis.

Clinical Applications of Aneuploidies in Evolution of NSCLC Patients: Current Status and Application Prospect

As one of the first characteristics of cancer cells, chromosomal aberrations during cell division have been well documented. Aneuploidy is a feature of most cancer cells accompanied by an elevated rate of mis-segregation of chromosomes, called chromosome instability (CIN). Aneuploidy causes ongoing karyotypic changes that contribute to tumor heterogeneity, drug resistance, and treatment failure, which are considered predictors of poor prognosis. Lung cancer (LC) is the leading cause of cancer-related deaths worldwide, and its genome map shows extensive aneuploid changes. Elucidating the role of aneuploidy in the pathogenesis of LC will reveal information about the key factors of tumor occurrence and development, help to predict the prognosis of cancer, clarify tumor evolution, metastasis, and drug response, and may promote the development of precision oncology. In this review, we describe many possible causes of aneuploidy and provide evidence of the role of aneuploidy in the evolution of LC, providing a basis for future biological and clinical research.

AURKB as a Promising Prognostic Biomarker in Hepatocellular Carcinoma

The Aurora kinases form a family of 3 genes encoding serine/threonine kinases and are involved in the regulation of cell division during the mitosis. This study was designed to investigate the prognostic role of Aurora kinases in hepatocellular carcinoma (HCC). In this study, we analyzed the expression, overall survival (OS) data, promoter methylation level, and relationship with immunoinhibitors of Aurora kinases in patients with HCC from GEPIA2, UALCAN, OncoLnc, and TISIDB databases. Protein-protein interaction (PPI) network, gene ontology, Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome pathway analysis were performed using the STRING database and Cytoscape software. We found that the mRNA expression, stages of HCC, and OS of AURKA and AURKB in HCC tissues were significantly different from control tissues, but there were significant inconsistencies in promoter methylation level and relationship with immunoinhibitors for AURKA and AURKB. None of the above items were significantly different for AURKC. Furthermore, a hub module including AURKA, AURKB, and AURKC was identified within the PPI network constructed with the Molecular Complex Detection (MCODE) plug-in in Cytoscape software. Our results show that AURKB could be a potential biomarker for HCC prognosis.

CNOT3 interacts with the Aurora B and MAPK/ERK kinases to promote survival of differentiating mesendodermal progenitor cells

Mesendoderm cells are key intermediate progenitors that form at the early primitive streak (PrS) and give rise to mesoderm and endoderm in the gastrulating embryo. We have identified an interaction between CNOT3 and the cell cycle kinase Aurora B that requires sequences in the NOT box domain of CNOT3 and regulates MAPK/ERK signaling during mesendoderm differentiation. Aurora B phosphorylates CNOT3 at two sites located close to a nuclear localization signal and promotes localization of CNOT3 to the nuclei of mouse embryonic stem cells (ESCs) and metastatic lung cancer cells. ESCs that have both sites mutated give rise to embryoid bodies that are largely devoid of mesoderm and endoderm and are composed mainly of cells with ectodermal characteristics. The mutant ESCs are also compromised in their ability to differentiate into mesendoderm in response to FGF2, BMP4, and Wnt3 due to reduced survival and proliferation of differentiating mesendoderm cells. We also show that the double mutation alters the balance of interaction of CNOT3 with Aurora B and with ERK and reduces phosphorylation of ERK in response to FGF2. Our results identify a potential adaptor function for CNOT3 that regulates the Ras/MEK/ERK pathway during embryogenesis.

Aurora kinase inhibitors as potential anticancer agents: Recent advances

Aurora kinases are a family of serine/threonine kinases that play a crucial role in cell proliferation through the regulation of mitotic spindles. These kinases are the regulatory proteins localized in the various phases of the cell cycle and are involved in centrosome maturation, chromosome alignment, chromosomal segregation, and cytokinesis. They have emerged as one of the validated drug targets for anticancer drug discovery as their overexpression has been implicated in the pathogenesis of various carcinomas. Inhibitors of Aurora kinases induce growth inhibition and apoptosis in a variety of tumor cells. Hence, the design and development of Aurora kinase inhibitors have been widely explored in recent years by the scientific community as potential anticancer agents. Various Aurora kinase inhibitors have been under preclinical and clinical investigations as antitumor agents. This review summarizes the recent strategies of various researchers for the design and development of Aurora kinase inhibitors belonging to different structural classes. Their bioactivity, SARs, molecular modelling, and mechanistic studies have also been described. The comprehensive compilation of research work carried out in the field will provide inevitable scope for the design and development of novel drug candidates with better selectivity and efficacy. The review is constructed after the exhaustive research in this discipline and includes the papers from 2011 to 2020.

Alternative approaches to target Myc for cancer treatment

The Myc proto-oncogene family consists of three members, C-MYC, MYCN, and MYCL, which encodes the transcription factor c-Myc (hereafter Myc), N-Myc, and L-Myc, respectively. Myc protein orchestrates diverse physiological processes, including cell proliferation, differentiation, survival, and apoptosis. Myc modulates about 15% of the global transcriptome, and its deregulation rewires the cellular signaling modules inside tumor cells, thereby acquiring selective advantages. The deregulation of Myc occurs in >70% of human cancers, and is related to poor prognosis; hence, hyperactivated Myc oncoprotein has been proposed as an ideal drug target for decades. Nevertheless, no specific drug is currently available to directly target Myc, mainly because of its "undruggable" properties: lack of enzymatic pocket for conventional small molecules to bind; inaccessibility for antibody due to the predominant nucleus localization of Myc. Although the topic of targeting Myc has actively been reviewed in the past decades, exciting new progresses in this field keep emerging. In this review, after a comprehensive summarization of valuable sources for potential druggable targets of Myc-driven cancer, we also peer into the promising future of utilizing macropinocytosis to deliver peptides like Omomyc or antibody agents to intracellular compartment for cancer treatment.

Aurora Kinase B Expression, Its Regulation and Therapeutic Targeting in Human Retinoblastoma

Purpose

Aurora kinase B (AURKB) plays a pivotal role in the regulation of mitosis and is gaining prominence as a therapeutic target in cancers; however, the role of AURKB in retinoblastoma (RB) has not been studied. The purpose of this study was to determine if AURKB plays a role in RB, how its expression is regulated, and whether it could be specifically targeted.

Methods

The protein expression of AURKB was determined using immunohistochemistry in human RB patient specimens and immunoblotting in cell lines. Pharmacological inhibition and shRNA-mediated knockdown were used to understand the role of AURKB in cell viability, apoptosis, and cell cycle distribution. Cell viability in response to AURKB inhibition was also assessed in enucleated RB specimens. Immunoblotting was employed to determine the protein levels of phospho-histone H3, p53, p21, and MYCN. Chromatin immunoprecipitation-qPCR was performed to verify the binding of MYCN on the promoter region of AURKB.

Results

The expression of AURKB was found to be markedly elevated in human RB tissues, and the overexpression significantly correlated with optic nerve and anterior chamber invasion. Targeting AURKB with small-molecule inhibitors and shRNAs resulted in reduced cell survival and increased apoptosis and cell cycle arrest at the G2/M phase. More importantly, primary RB specimens showed decreased cell viability in response to pharmacological AURKB inhibition. Additional studies have demonstrated that the MYCN oncogene regulates the expression of AURKB in RB.

Conclusions

AURKB is overexpressed in RB, and targeting it could serve as a novel therapeutic strategy to restrict tumor cell growth.

Therapeutic Potential of Regorafenib-A Multikinase Inhibitor in Pulmonary Hypertension

Pulmonary hypertension (PH) is characterized by a progressive elevation of mean arterial pressure followed by right ventricular failure and death. Previous studies have indicated that numerous inhibitors of receptor tyrosine kinase signaling could be either beneficial or detrimental for the treatment of PH. Here we investigated the therapeutic potential of the multi-kinase inhibitor regorafenib (BAY 73-4506) for the treatment of PH. A peptide-based kinase activity assay was performed using the PamStation^®12 platform. The 5-bromo-2′-deoxyuridine proliferation and transwell migration assays were utilized in pulmonary arterial smooth muscle cells (PASMCs). Regorafenib was administered to monocrotaline- and hypoxia-induced PH in rats and mice, respectively. Functional parameters were analyzed by hemodynamic and echocardiographic measurements. The kinase activity assay revealed upregulation of twenty-nine kinases in PASMCs from patients with idiopathic PAH (IPAH), of which fifteen were established as potential targets of regorafenib. Regorafenib showed strong anti-proliferative and anti-migratory effects in IPAH-PASMCs compared to the control PASMCs. Both experimental models indicated improved cardiac function and reduced pulmonary vascular remodeling upon regorafenib treatment. In lungs from monocrotaline (MCT) rats, regorafenib reduced the phosphorylation of c-Jun N-terminal kinase and extracellular signal-regulated kinase 1/2. Overall, our data indicated that regorafenib plays a beneficial role in experimental PH.

Long noncoding RNA: A resident staff of genomic instability regulation in tumorigenesis

Genomic instability is an important characteristic of cancer, which promotes clonal evolution and tumorigenesis by increasing the frequency of gene destruction and loss of genome integrity. Generally, the maintenance of genomic stability depends significantly on the accurate regulation and timely repair of different genomic scales, ranging from DNA sequence to chromatin higher-order structures to chromosomes. Once irreversible damage and imperfect repair occurred, the resulting genomic instability can lead to a higher risk of tumorigenesis. However, how these factors disrupt genomic stability and their specific tumorigenic mechanisms remain unclear. Inspiringly, numerous studies have confirmed that long noncoding RNAs (lncRNAs), an important regulator of epigenetic inheritance, are functional in such process. Thus, this review aimed to discuss the vital factors that may lead to genomic instability at these multiple genomic scales, with an emphasis on the role of lncRNAs in it.

Aurora-B knockdown inhibits osteosarcoma metastasis by inducing autophagy via the mTOR/ULK1 pathway

Background

Autophagy plays an essential role in metastasis of malignancies. Although our studies showed that Aurora-B facilitate pulmonary metastasis in OS, the mechanism of Aurora-B kinase on autophagy and metastasis in OS has not been explored.

Methods

Clinical-pathological parameters and follow-up information was collected in OS patients. Immunohistochemical staining was performed to detect Aurora-B and LC3 protein in OS tissues. Short hairpin RNA transfection was used to silence Aurora-B in OS cells. Real-time quantitative PCR (RT-qPCR) was performed to detect Aurora-B mRNA expression in OS cells. Aurora-B and autophagy related protein were measured by Western blot. Transmission electron microscopy and laser scanning confocal microscopy were performed to observe the formation of autophagosomes and autolysosomes. Migratory and invasive ability of OS cells were measured by Wound healing and transwell assays. Orthotopic xenograft model was used to evaluate the effect of autophagy mediated by Aurora-B inhibition on pulmonary metastasis of OS.

Results

The elevated expression of Aurora-B protein in OS tissues negatively associated with the overall survival of OS patients. Further investigation has found that Aurora-B expression was negatively correlative with autophagy related protein LC3 in OS patient tissues. Knockdown Aurora-B stimulates autophagy and inhibits migratory and invasive ability of OS cells. Mechanistically, Aurora-B knockdown suppressed the mTOR/ULK1 signaling pathway and reactivation of the mTOR/ULK1 pathway decreased autophagy level. Furthermore, the inhibition effect of silencing Aurora-B on migration and invasion of OS was reversed by chloroquine and mTOR activator in vitro and vivo.

Conclusions

Our results suggest that silencing of Aurora-B stimulate autophagy via decreasing mTOR/ULK1 and result in inhibiting OS metastasis. Targeted Aurora-B/mTOR/ULK1 pathway may be a promising treatment strategy for OS patients.

Promising Therapy in Lung Cancer: Spotlight on Aurora Kinases

Simple Summary

Lung cancer has remained one of the major causes of death worldwide. Thus, a more effective treatment approach is essential, such as the inhibition of specific cancer-promoting molecules. Aurora kinases regulate the process of mitosis—a process of cell division that is necessary for normal cell proliferation. Dysfunction of these kinases can contribute to cancer formation. In this review, we present studies indicating the implication of Aurora kinases in tumor formation, drug resistance, and disease prognosis. The effectivity of using Aurora kinase inhibitors in the pre-clinical and clinical investigations has proven their therapeutic potential in the setting of lung cancer. This work may provide further information to broaden the development of anticancer drugs and, thus, improve the conventional lung cancer management.

Abstract

Despite tremendous efforts to improve the treatment of lung cancer, prognosis still remains poor; hence, the search for efficacious therapeutic option remains a prime concern in lung cancer research. Cell cycle regulation including mitosis has emerged as an important target for cancer management. Novel pharmacological agents blocking the activities of regulatory molecules that control the functional aspects of mitosis such as Aurora kinases are now being investigated. The Aurora kinases, Aurora-A (AURKA), and Aurora B (AURKB) are overexpressed in many tumor entities such as lung cancer that correlate with poor survival, whereby their inhibition, in most cases, enhances the efficacy of chemo-and radiotherapies, indicating their implication in cancer therapy. The current knowledge on Aurora kinase inhibitors has increasingly shown high potential in ensuing targeted therapies in lung malignancies. In this review, we will briefly describe the biology of Aurora kinases, highlight their oncogenic roles in the pre-clinical and clinical studies in lung cancer and, finally, address the challenges and potentials of Aurora kinases to improve the therapy of this malignancy.

Vibrational, spectroscopic, chemical reactivity, molecular docking and in vitro anticancer activity studies against A549 lung cancer cell lines of 5-Bromo-indole-3-carboxaldehyde

Spectroscopic investigations are performed for 5-Bromo-1H-indole-carboxaldehyde by using experimental (FT-IR, FT-Raman) and theoretical (DFT) calculations. Vibrational assignments of the fundamental modes were assigned on the basis of Potential energy distribution (PED) calculations. Electron Localization Function (ELF) and Local Orbital Localizer (LOL) studies were performed to visualize the electron delocalization in the molecule. Frontier molecular orbitals (FMOs) and related molecular properties were computed. The electron-hole distribution of the molecule was also computed using Multiwfn 3.3.9 software to predict the charge transfer within the molecule. The total and partial density of states (TDOS and PDOS) and also the overlap population density of states (OPDOS) spectra were simulated. UV-Vis spectrum of the compound was also recorded. The reactive sites of the compound were studied from the MEP and Fukui function analysis. The charge delocalization and stability of the title molecule were investigated using natural bond orbital (NBO) analysis. The lung cancer activity of the title compound against p53 tumor suppressor proteins was studied using molecular docking analysis. The in-vitro cytotoxic activity of the molecule against human pulmonary lung cancer cell lines (A549) was determined by MTT assay.

[Aurora kinase-B silencing promotes apoptosis of osteosarcoma 143B cells by ULK1 phosphorylation-induced autophagy]

OBJECTIVE

To investigate the effect of Aurora kinase B (AURKB) silencing-induced autophagy on apoptosis of osteosarcoma 143B cells and the underlying molecular mechanisms.

METHODS

Human osteosarcoma 143B cells were transfected with Lv/shAURKB or the negative control vector Lv/shScrambled followed by treatment with chloroquine (CQ) for 24 h. Western blotting was performed to detect the protein expression levels of AURKB, P62, LC3, cleaved caspase-3, Bcl-2, and P-ULK1Ser555. Transmission electron microscopy and LC3 dual-label fluorescence method were used to trace the autophagosomes in 143B cells to assess cell autophagy, and the cell apoptosis was detected using flow cytometry and TUNEL assay. Co-immunoprecipitation assay was used to detect the interaction between AURKB and ULK1.

RESULTS

The ratio of autophagy-related proteins LC3 II/I and the number of autophagosomes were significantly increased in 143B cells after transfection with Lv/shAURKB (P < 0.05), which significantly increased the expression of cleaved caspase-3 and reduced the expression of Bcl-2 (P < 0.05). Combined treatment of the cells with Lv/shAURKB and the autophagy inhibitor chloroquine obviously restored the expressions of caspase-3 and Bcl-2 (P < 0.05). Transfection with Lv/shAURKB significantly increased the apoptosis rate of 143B cells (P < 0.05), and this effect was significantly antagonized by combined treatment with chloroquine (P < 0.05). AURKB silencing strongly activated the phosphorylation of the autophagy-initiating protein ULK1Ser555 in 143B cells (P < 0.05). The results of co-immunoprecipitation assay confirmed when AURKB was immunoprecipitated, ULK1 also precipitated.

CONCLUSIONS

Silencing AURKB can induce autophagy by activating ULK1Ser555 phosphorylation to promote apoptosis in 143B cells.

Identification of key differentially expressed mRNAs and microRNAs in non-small cell lung cancer using bioinformatics analysis

Non-small cell lung cancer (NSCLC) is a leading cause of mortality worldwide. However, the pathogenesis of NSCLC remains to be fully elucidated. Therefore, the present study aimed to explore the differential expression of mRNAs and microRNAs (miRNAs/miRs) in NSCLC and to determine how these RNA molecules interact with one another to affect disease progression. Differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) were identified from the GSE18842, GSE32863 and GSE29250 datasets downloaded from the Gene Expression Omnibus (GEO database). Functional and pathway enrichment analysis were performed based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. STRING, Cytoscape and MCODE were applied to construct a protein-protein interaction (PPI) network and to screen hub genes. The interactions between miRNAs and mRNAs were predicted using miRWalk 3.0 and a miRNA-mRNA regulatory network was constructed. The prognostic value of the identified hub genes was then evaluated via Kaplan-Meier survival analyses using datasets from The Cancer Genome Atlas. A total of 782 DEGs and 46 DEMs were identified from the 3 GEO datasets. The enriched pathways and functions of the DEGs and target genes of the DEMs included osteoclast differentiation, cell adhesion, response to a drug, plasma membrane, extracellular exosome and protein binding. A subnetwork composed of 11 genes was extracted from the PPI network and the genes in this subnetwork were mainly involved in the cell cycle, cell division and DNA replication. A miRNA-gene regulatory network was constructed with 247 miRNA-gene pairs based on 6 DEMs and 210 DEGs. Kaplan-Meier survival analysis indicated that the expression of ubiquitin E2 ligase C, cell division cycle protein 20, DNA topoisomerase IIα, aurora kinase A and B, cyclin B2, maternal embryonic leucine zipper kinase, slit guidance ligand 3, phosphoglucomutase 5, endomucin, cysteine dioxygenase type 1, dihydropyrimidinase-like 2, miR-130b, miR-1181 and miR-127 was significantly associated with overall survival of patients with lung adenocarcinoma. In the present study, a miRNA-mRNA regulatory network in NSCLC was established, which may provide future avenues for scientific exploration and therapeutic targeting of NSCLC.

AURKB Promotes the Metastasis of Gastric Cancer, Possibly by Inducing EMT

AIM

To investigate the function of Aurora kinase B (AURKB) in gastric cancer (GC).

METHODS

Immunohistochemistry was used to assay the expression of AURKB in 50 pairs of GC and adjacent tissues, and qRT-PCR was conducted to test AURKB expression in normal gastric epithelial and GC cell lines. Two segments of small interference RNAs (siRNAs) targeting AURKB were synthesized and inserted into GV248 lentivirus vector. After transfected with LV-AURKB-RNAis, CCK8, wound healing, transwell and flow cytometric assays were performed to determine the influence of silencing AURKB on cell proliferation, invasion, migration, cell cycles and apoptosis of GC cells, and the expression of EMT (epithelial-mesenchymal transition)-related markers was demonstrated by Western blots (WB).

RESULTS

AURKB was highly expressed in GC and closely associated with lymph node metastasis and advanced stages of GC. Down-regulating AURKB suppressed the proliferation and promoted the apoptosis of GC cells, arrested the cell cycle in G2/M phase, and inhibited the invasion and migration of GC cells. The expression levels of AKT1, mTOR, Myc, MMP2, and VEGFA were decreased, while the expression levels of OCLN and JUP were increased after knocking down of AURKB in both AGC and MKN45 cells.

CONCLUSION

AURKB is overexpressed in GC and closely associated with clinicopathologic characteristics of GC. It is likely that by inhibiting VEGFA/Akt/mTOR and Wnt/β-catenin/Myc pathways, silenced AURKB could inhibit the invasive and migratory abilities of GC cells. However, because of the small sample size and the absence of in-vivo experiments, these results should be verified by further studies.

Discovery of SP-96, the first non-ATP-competitive Aurora Kinase B inhibitor, for reduced myelosuppression

Aurora Kinase B is a serine-threonine kinase known to be overexpressed in several cancers, with no inhibitors approved for clinical use. Herein, we present the discovery and optimization of a series of novel quinazoline-based Aurora Kinase B inhibitors. The lead inhibitor SP-96 shows sub-nanomolar potency in Aurora B enzymatic assays (IC₅₀ = 0.316 ± 0.031 nM). We identified the important pharmacophore features resulting in selectivity against receptor tyrosine kinases. Particularly, SP-96 shows >2000 fold selectivity against FLT3 and KIT which is important for normal hematopoiesis. This could diminish the adverse effect of neutropenia reported in the clinical trials of the Aurora B inhibitor Barasertib, which inhibits FLT3 and KIT in addition to Aurora B. Enzyme kinetics of SP-96 shows non-ATP-competitive inhibition which makes it a first-in-class inhibitor. Further, SP-96 shows selective growth inhibition in NCI60 screening, including inhibition of MDA-MD-468, a Triple Negative Breast Cancer cell line.

Viral-Mediated AURKB Cleavage Promotes Cell Segregation and Tumorigenesis

Aurora kinase B (AURKB), a central regulator of chromosome segregation and cytokinesis, is aberrantly expressed in various cancer cells. However, the relationship of AURKB and oncogenic viruses in cancer progression remains unclear. Here, we reveal that N-cleaved isoforms of AURKB exist in several oncovirus-associated tumor cells and patient cancer tissues, including Kaposi's sarcoma-associated herpesvirus (KSHV), Epstein-Barr virus (EBV), and human papillomavirus virus (HPV). Mechanistically, in KSHV-infected tumor cells, the latent viral antigen LANA cleaves AURKB at Asp⁷⁶ in a serine protease-dependent manner. The N'-AURKB relocalizes to the spindle pole and promotes the metaphase-to-telophase transition in mitotic cells. Introduction of N'-AURKB but not C'-AURKB promotes colony formation and malignant growth of tumor cells in vitro and in vivo using a murine xenograft model. Altogether, our findings uncover a proteolytic cleavage mechanism by which oncoviruses induce cancer cell segregation and tumorigenesis.

Genome-wide CRISPR screen uncovers a synergistic effect of combining Haspin and Aurora kinase B inhibition

Aurora kinases are a family of serine/threonine kinases vital for cell division. Because of the overexpression of Aurora kinases in a broad range of cancers and their important roles in mitosis, inhibitors targeting Aurora kinases have attracted attention in cancer therapy. VX-680 is an effective pan-Aurora kinase inhibitor; however, its clinical efficacy was not satisfying. In this study, we performed CRISPR/Cas9 screens to identify genes whose depletion shows synthetic lethality with VX-680. The top hit from these screens was GSG2 (also known as Haspin), a serine/threonine kinase that phosphorylates histone H3 at Thr-3 during mitosis. Moreover, both Haspin knockout and Haspin inhibitor-treated HCT116 cells were hypersensitive to VX-680. Furthermore, we showed that the synthetic lethal interaction between Haspin depletion and VX-680 was mediated by the inhibition of Haspin with Aurora kinase B (AURKB), but not with Aurora kinase A (AURKA). Strikingly, combined inhibition of Haspin and AURKB had a better efficacy than single-agent treatment in both head and neck squamous cell carcinoma and non-small cell lung cancer. Taken together, our findings have uncovered a synthetic lethal interaction between AURKB and Haspin, which provides a strong rationale for this combination therapy for cancer patients.

Direct Phosphorylation and Stabilization of MYC by Aurora B Kinase Promote T-cell Leukemogenesis

Deregulation of MYC plays an essential role in T cell acute lymphoblastic leukemia (T-ALL), yet the mechanisms underlying its deregulation remain elusive. Herein, we identify a molecular mechanism responsible for reciprocal activation between Aurora B kinase (AURKB) and MYC. AURKB directly phosphorylates MYC at serine 67, counteracting GSK3β-directed threonine 58 phosphorylation and subsequent FBXW7-mediated proteasomal degradation. Stabilized MYC, in concert with T cell acute lymphoblastic leukemia 1 (TAL1), directly activates AURKB transcription, constituting a positive feedforward loop that reinforces MYC-regulated oncogenic programs. Therefore, inhibitors of AURKB induce prominent MYC degradation concomitant with robust leukemia cell death. These findings reveal an AURKB-MYC regulatory circuit that underlies T cell leukemogenesis, and provide a rationale for therapeutic targeting of oncogenic MYC via AURKB inhibition.

Overexpression of PRC1 indicates a poor prognosis in ovarian cancer

Protein regulator of cytokinesis-1 (PRC1) is a microtubule-associated factor involved in cytokinesis. Recent studies have indicated that PRC1 overexpression is involved in tumorigenesis in multiple types of human cancer. However, the expression, biological functions and the prognostic significance of PRC1 in ovarian cancer have not yet been clarified. In this study, it was confirmed that the PRC1 mRNA and protein expression levels were upregulated in high-grade serous ovarian carcinoma (HGSOC) tissues, particularly in patients without breast cancer susceptibility gene (BRCA) pathogenic mutations. PRC1 overexpression contributed to drug resistance, tumor recurrence and a poor prognosis. The findings also indicated that PRC1 knockdown decreased the proliferation, metastasis and multidrug resistance of ovarian cancer cells in vitro. It was also demonstrated that forkhead box protein M1 (FOXM1) regulated the mRNA and protein expression of PRC1. Dual-luciferase reporter assay and rescue assay confirmed that PRC1 was a direct crucial downstream target of FOXM1. On the whole, the findings of this study confirmed that PRC1 was a major prognostic factor of HGSOC and a promising therapeutic biomarker for the treatment of ovarian cancer.

Comprehensive analysis of TPX2-related ceRNA network as prognostic biomarkers in lung adenocarcinoma

Background and aim: Competing endogenous RNA (ceRNA) is believed to play vital roles in tumorigenesis. The goal of this study was to screen prognostic biomarkers in lung adenocarcinoma (LUAD). Methods: Common differentially expressed genes (DEGs) were collected from Gene Expression Omnibus (GEO) databases and The Cancer Genome Atlas databases (TCGA) using GEO2R and "limma" package in R, respectively. Overlapping DEGs were conducted using enrichment of functions and protein-protein interaction (PPI) network to discover significant candidate genes. By using a comprehensive analysis, we constructed an mRNA mediated ceRNA network. Survival rates were used Kaplan-Meier analysis. Statistical analysis was used to further identify the prognosis of studied genes. Results: Integrated analysis of GSE32863 and TCGA databases, a total of 886 overlapping DEGs, including 279 up-regulated and 607 down-regulated genes were identified. Considering the highest term of candidate genes in PPI, we identified TPX2, which was enriched in cell division signaling pathway. Besides, 35 differentially expressed miRNAs (DEmiRNAs) were predicted to target TPX2 and only 7 DEmiRNAs were identified to be prognostic biomarkers in LUAD. Then, 30 differentially expressed lncRNAs (DElncRNAs) were predicted to bind these 7 DEmiRNAs. Finally, we found that 7 DElncRNAs were correlated with the overall survival (all p <0.05). Furthermore, we identified elevated TPX2 was strongly correlated with the worse survival rate among 458 samples. Univariate and multivariate cox analysis showed TPX2 may act as an independent factor for prognosis in LUAD (p <0.05). Then pathway enrichment results suggested that TPX2 may facilitate tumorigenesis by participating in several cancer-related signaling pathways in LUAD, especially in Notch signal pathway. Conclusions: TPX2-related lncRNAs and miRNAs are related to the survival of LUAD. 7 lncRNAs, 7 miRNAs and TPX2 may serve as prognostic biomarkers in LUAD.

Structural Characterization of the Aurora Kinase B "DFG-flip" Using Metadynamics

Aurora kinase B (AKB), a Ser/Thr kinase that plays a crucial role in mitosis, is overexpressed in several cancers. Clinical inhibitors targeting AKB bind to the active DFG "in" conformation of the kinase. It would be beneficial, however, to understand if AKB is susceptible to type II kinase inhibitors that bind to the inactive, DFG "out" conformation, since type II inhibitors achieve higher kinome selectivity and higher potency in vivo. The DFG "out" conformation of AKB is not yet experimentally determined which makes the design of type II inhibitors exceedingly difficult. An alternate approach is to simulate the DFG "out" conformation from the experimentally determined DFG "in" conformation using atomistic molecular dynamics (MD) simulation. In this work, we employed metadynamics (MTD) approach to simulate the DFG "out" conformation of AKB by choosing the appropriate collective variables. We examined structural changes during the DFG-flip and determined the interactions crucial to stabilize the kinase in active and inactive states. Interestingly, the MTD approach also identified a unique transition state (DFG "up"), which can be targeted by small molecule inhibitors. Structural insights about these conformations is essential for structure-guided design of next-generation AKB inhibitors. This work also emphasizes the usefulness of MTD simulations in predicting macromolecular conformational changes at reduced computational costs.

AURKB as a target in non-small cell lung cancer with acquired resistance to anti-EGFR therapy

Non-small cell lung cancer (NSCLC) tumors harboring mutations in EGFR ultimately relapse to therapy with EGFR tyrosine kinase inhibitors (EGFR TKIs). Here, we show that resistant cells without the p.T790M or other acquired mutations are sensitive to the Aurora B (AURKB) inhibitors barasertib and S49076. Phospho-histone H3 (pH3), a major product of AURKB, is increased in most resistant cells and treatment with AURKB inhibitors reduces the levels of pH3, triggering G1/S arrest and polyploidy. Senescence is subsequently induced in cells with acquired mutations while, in their absence, polyploidy is followed by cell death. Finally, in NSCLC patients, pH3 levels are increased after progression on EGFR TKIs and high pH3 baseline correlates with shorter survival. Our results reveal that AURKB activation is associated with acquired resistance to EGFR TKIs, and that AURKB constitutes a potential target in NSCLC progressing to anti-EGFR therapy and not carrying resistance mutations.

Non-small cell lung cancer with EGFR mutations are known to develop resistance to EGFR tyrosine kinase inhibitors. Here, the authors show AURKB activation to be associated with resistance in EGFR mutant lung cancer cells, and that AURKB is a therapeutic target in resistant tumours that lack the p.T790M or other acquired mutations.

Integrated analysis reveals key genes with prognostic value in lung adenocarcinoma

Background

Lung cancer is one of the most common malignant tumors. Despite advances in lung cancer therapies, prognosis of non-small-cell lung cancer is still unfavorable. The aim of this study was to identify the prognostic value of key genes in lung tumorigenesis.

Methods

Differentially expressed genes (DEGs) were screened out by GEO2R from three Gene Expression Omnibus cohorts. Common DEGs were selected for Kyoto Encyclopedia of Genes and Genomes pathway analysis and Gene Ontology enrichment analysis. Protein– protein interaction networks were constructed by the STRING database and visualized by Cytoscape software. Hub genes, filtered from the CytoHubba, were validated using the Gene Expression Profiling Interactive Analysis database, and their genomic alterations were identified by performing the cBioportal. Finally, overall survival analysis of hub genes was performed using Kaplan–Meier Plotter.

Results

From three datasets, 169 DEGs (70 upregulated and 99 downregulated) were identified. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses showed that upregulated DEGs were significantly enriched in cell cycle, p53 pathway, and extracellular matrix–receptor interactions; the downregulated DEGs were significantly enriched in PPAR pathway and tyrosine metabolism. The protein–protein interaction network consisted of 71 nodes and 305 edges, including 49 upregulated and 22 downregulated genes. The hub genes, including AURKB, BUB1B, KIF2C, HMMR, CENPF, and CENPU, were overexpressed compared with the normal group by Gene Expression Profiling Interactive Analysis analysis, and associated with reduced overall survival in lung cancer patients. In the genomic alterations analysis, two hotspot mutations (S2021C/F and E314K/V) were identified in Pfam protein domains.

Conclusion

DEGs, including AURKB, BUB1B, KIF2C, HMMR, CENPF, and CENPU, might be potential biomarkers for the prognosis and treatment of lung adenocarcinoma.

Butein suppresses hepatocellular carcinoma growth via modulating Aurora B kinase activity

Aurora B is aberrantly expressed in various tumors and shown to be a promising target for cancer therapy. Butein, a chalcone isolated from Rhus cerniciflua, has demonstrated antitumor activities in different cancers. In this study, we aimed to validate whether Aurora B kinase was the direct target of butein to exhibit its potency in hepatocellular carcinoma (HCC). Comparing with the normal cell line and tissue, Aurora B was overexpressed in all tested HCC cells and the majority of tumor tissue. Knocking down of Aurora B with shRNA substantially inhibited HCC cell proliferation, colony formation and delayed tumor growth in nude mice. Except computer docking, a series of kinase assays revealed butein directly interacted with Aurora B and inhibited its kinase activity. Along with the decrease of Aurora B and histone H3 phosphorylation, HCC cells were induced G2/M cell cycle arrest and subjected to cell apoptosis. Butein-mediated antitumor activities were substantially impaired in Aurora B knockdown cells, suggesting Aurora B was an important target of butein in HCC. Oral administration of butein substantially restrained HCC xenograft growth and the expressions of Ki67 and phosphor-histone H3 were significantly decreased in butein-treated tissue. To the best of our knowledge, our studies revealed that Aurora B was the direct target of butein in HCC.

Inhibiting polo-like kinase 1 enhances radiosensitization via modulating DNA repair proteins in non-small-cell lung cancer

To assure faithful chromosome segregation, cells make use of the spindle assembly checkpoint, which can be activated in aneuploid cancer cells. In this study, the efficacies of inhibiting polo-like kinase 1 (PLK1) on the radiosensitization of non-small-cell lung cancer (NSCLC) cells were studied. Clonogenic survival assay was performed to identify the effects of the PLK1 inhibitor on radiosensitivity within NSCLC cells. Mitotic catastrophe assessment was used to measure the cell death and histone H2AX protein (γH2AX) foci were utilized to assess the DNA double-strand breaks (DSB). The transcriptome was analyzed via unbiased profiling of microarray expression. The results showed that the postradiation mitotic catastrophe induction and the DSB repair were induced by PLK1 inhibitor BI-6727, leading to an increase in the radiosensitivity of NSCLC cells. BI-6727 in combination with radiation significantly induced the delayed tumor growth. PLK1-silenced NSCLC cells showed an altered mRNA and protein expression related to DNA damaging, replication, and repairing, including the DNA-dependent protein kinase (DNAPK) and topoisomerase II alpha (TOPO2A). Furthermore, inhibition of PLK1 blocked 2 important DNA repair pathways. To summarize, our study showed PLK1 kinase as an option in the therapy of NSCLC.

RIPK1-dependent cell death: a novel target of the Aurora kinase inhibitor Tozasertib (VX-680)

The Aurora kinase family (Aurora A, B and C) are crucial regulators of several mitotic events, including cytokinesis. Increased expression of these kinases is associated with tumorigenesis and several compounds targeting Aurora kinase are under evaluation in clinical trials (a.o. AT9283, AZD1152, Danusertib, MLN8054). Here, we demonstrate that the pan-Aurora kinase inhibitor Tozasertib (VX-680 and MK-0457) not only causes cytokinesis defects through Aurora kinase inhibition, but is also a potent inhibitor of necroptosis, a cell death process regulated and executed by the RIPK1, RIPK3 and MLKL signalling axis. Tozasertib’s potency to inhibit RIPK1-dependent necroptosis and to block cytokinesis in cells is in the same concentration range, with an IC50 of 1.06 µM and 0.554 µM, respectively. A structure activity relationship (SAR) analysis of 67 Tozasertib analogues, modified at 4 different positions, allowed the identification of analogues that showed increased specificity for either cytokinesis inhibition or for necroptosis inhibition, reflecting more specific inhibition of Aurora kinase or RIPK1, respectively. These results also suggested that RIPK1 and Aurora kinases are functionally non-interacting targets of Tozasertib and its analogues. Indeed, more specific Aurora kinase inhibitors did not show any effect in necroptosis and Necrostatin-1s treatment did not result in cytokinesis defects, demonstrating that both cellular processes are not interrelated. Finally, Tozasertib inhibited recombinant human RIPK1, human Aurora A and human Aurora B kinase activity, but not RIPK3. The potency ranking of the newly derived Tozasertib analogues and their specificity profile, as observed in cellular assays, coincide with ADP-Glo recombinant kinase activity assays. Overall, we show that Tozasertib not only targets Aurora kinases but also RIPK1 independently, and that we could generate analogues with increased selectivity to RIPK1 or Aurora kinases, respectively.

G2/M inhibitors as pharmacotherapeutic opportunities for glioblastoma: the old, the new, and the future

Glioblastoma (GBM) is one of the deadliest tumors and has a median survival of 3 months if left untreated. Despite advances in rationally targeted pharmacological approaches, the clinical care of GBM remains palliative in intent. Since the majority of altered signaling cascades involved in cancer establishment and progression eventually affect cell cycle progression, an alternative approach for cancer therapy is to develop innovative compounds that block the activity of crucial molecules needed by tumor cells to complete cell division. In this context, we review promising ongoing and future strategies for GBM therapeutics aimed towards G2/M inhibition such as anti-microtubule agents and targeted therapy against G2/M regulators like cyclin-dependent kinases, Aurora inhibitors, PLK1, BUB, 1, and BUBR1, and survivin. Moreover, we also include investigational agents in the preclinical and early clinical settings. Although several drugs were shown to be gliotoxic, most of them have not yet entered therapeutic trials. The use of either single exposure or a combination with novel compounds may lead to treatment alternatives for GBM patients in the near future.

Aurora kinases: novel therapy targets in cancers

Aurora kinases, a family of serine/threonine kinases, consisting of Aurora A (AURKA), Aurora B (AURKB) and Aurora C (AURKC), are essential kinases for cell division via regulating mitosis especially the process of chromosomal segregation. Besides regulating mitosis, Aurora kinases have been implicated in regulating meiosis. The deletion of Aurora kinases could lead to failure of cell division and impair the embryonic development. Overexpression or gene amplification of Aurora kinases has been clarified in a number of cancers. And a growing number of studies have demonstrated that inhibition of Aurora kinases could potentiate the effect of chemotherapies. For the past decades, a series of Aurora kinases inhibitors (AKIs) developed effectively repress the progression and growth of many cancers both in vivo and in vitro, suggesting that Aurora kinases could be a novel therapeutic target. In this review, we'll first briefly present the structure, localization and physiological functions of Aurora kinases in mitosis, then describe the oncogenic role of Aurora kinases in tumorigenesis, we shall finally discuss the outcomes of AKIs combination with conventional therapy.

Characterization of a highly selective inhibitor of the Aurora kinases

Aurora kinases play an essential role in mitosis and cell cycle regulation. In recent years Aurora kinases have proved popular cancer targets and many inhibitors have been developed. The majority of these clinical candidates are multi-targeted, rendering them inappropriate as tools for studying Aurora kinase mediated signaling. Here we report discovery of a highly selective inhibitor of Aurora kinases A, B and C, with potent cellular activity and minimal off-target activity (PLK4). The X-ray co-crystal structure of Aurora A in complex with compound 2 is reported, and provides insights into the structural determinants of ligand binding and selectivity.

Aurora B expression modulates paclitaxel response in non-small cell lung cancer

Background:

Taxanes are mitotic poisons widely used in the treatment of non-small cell lung cancer (NSCLC), however, little is known about potential molecular modulators of response to these compounds. Aurora B (AURKB) is a critical regulator of the mitotic spindle assembly, previously shown overexpressed in NSCLC. Here we investigated the hypothesis that AURKB expression modulates the efficacy of taxanes in NSCLC cells.

Methods:

AURKB mRNA expression was determined by qPCR in 132 frozen NSCLC tissues and nine NSCLC cell lines. Aurora B expression was knocked down in cell lines using multiple shRNA constructs. Barasertib was used to specifically inhibit AURKB activity, determined by the level of H3S10 phosphorylation.

Results:

Frequent AURKB mRNA upregulation was observed in NSCLC tissues (P<0.0001), being more prominent in squamous carcinomas (P<0.0001). Aurora B expression in cell lines strongly correlated with sensitivity to both docetaxel (P=0.004) and paclitaxel (P=0.007). Aurora B knockdown derivatives consistently showed a dose-dependent association between low-AURKB expression and resistance to paclitaxel. Specific chemical inhibition of Aurora B activity also demonstrated a strong dose-dependent efficiency in triggering paclitaxel resistance.

Conclusions:

Aurora B activity is an important modulator of taxane response in NSCLC cells. This may lead to further insights into taxane sensitivity of NSCLC tumours.

Quercetin suppresses lung cancer growth by targeting Aurora B kinase

aurora B kinase is highly expressed in several cancer cells and promotes tumorigenesis and progression, and therefore, it is an important target for drug to treat tumors. Quercetin was identified to be an antitumor agent. Herein, we report for the first time that quercetin inhibited aurora B activities by directly binding with aurora B in vitro and in vivo. Ex vivo studies showed that quercetin inhibited aurora B activities in JB6 Cl41 cells and A549 lung cancer cells. Moreover, knockdown of aurora B in A549 cells decreased their sensitivities to quercetin. In vivo study demonstrated that injection of quercetin in A549 tumor‐bearing mice effectively suppressed cancer growth. The phosphorylation of histone 3 in tumor tissues was also decreased after quercetin treatment. In short, quercetin can suppress growth of lung cancer cells as an aurora B inhibitor both in vitro and in vivo.

Aurora-A Kinase: A Potent Oncogene and Target for Cancer Therapy

The Aurora kinase family is comprised of three serine/threonine kinases, Aurora-A, Aurora-B, and Aurora-C. Among these, Aurora-A and Aurora-B play central roles in mitosis, whereas Aurora-C executes unique roles in meiosis. Overexpression or gene amplification of Aurora kinases has been reported in a broad range of human malignancies, pointing to their role as potent oncogenes in tumorigenesis. Aurora kinases therefore represent promising targets for anticancer therapeutics. A number of Aurora kinase inhibitors (AKIs) have been generated; some of which are currently undergoing clinical evaluation. Recent studies have unveiled novel unexpected functions of Aurora kinases during cancer development and the mechanisms underlying the anticancer actions of AKIs. In this review, we discuss the most recent advances in Aurora-A kinase research and targeted cancer therapy, focusing on the oncogenic roles and signaling pathways of Aurora-A kinases in promoting tumorigenesis, the recent preclinical and clinical AKI data, and potential alternative routes for Aurora-A kinase inhibition.

A mathematical model of Aurora B activity in prophase and metaphase

Aurora B kinase is a protein that controls several processes in mitosis when it is found associated with INCENP, Survivin and Borealin in a complex known as the Chromosomal Passenger Complex. Aurora B in complex with INCENP is phosphorylated on three sites, resulting in the full activation of Aurora B. In prophase and metaphase, Aurora B is activated at centromeres, the region of chromatin linking sister chromatids, due to an autophosphorylation mechanism, and it has been hypothesised that Aurora B is activated throughout the cytoplasm due to its concentration at centromeres. In this article, we first develop a time-dependent model of Aurora B activation that does not incorporate spatial variation. This model is used to demonstrate the various qualitative behaviours that the activation of Aurora B is capable of displaying for different model parameters. Next, we develop a spatio-temporal model of Aurora B activation that includes diffusion of soluble Aurora B and binding of Aurora B to immobile centromeric binding sites. This model describes the activation of Aurora B throughout the cytoplasm due to its concentration-dependent activation at centromeres. The models demonstrate the effects that a soluble phosphatase concentration, multisite phosphorylation and diffusion have on the activation of Aurora B.

Prolonged pemetrexed pretreatment augments persistence of cisplatin-induced DNA damage and eliminates resistant lung cancer stem-like cells associated with EMT

Background

Lung cancer is the leading cause of cancer-related mortality, and new therapeutic options are urgently needed. Non-small cell lung cancer (NSCLC) accounts for approximately 85 % of all lung cancers, with the current standard regimen of care for NSCLC including chemotherapy with pemetrexed as a single agent or in combination with platinum-based agents, e.g. cisplatin. Pemetrexed is a folic acid antagonist that inhibits the synthesis of precursor nucleotides, whereas cisplatin directly induces DNA adducts, the repair of which is dependent on sufficiently high nucleotide levels. In the clinical setting, the pemetrexed-cisplatin combination therapy is administered concomitantly. We hypothesized that prolonged pretreatment with pemetrexed could be beneficial, as prior depletion of nucleotide pools could sensitize cancer cells to subsequent treatment with cisplatin.

Methods

NSCLC A549 and H460 cells were treated with pemetrexed for 72 h. In addition, 24 h of cisplatin treatment was initiated at day 1, 2 or 3 resulting in either simultaneous pemetrexed application or pemetrexed pretreatment for 24 or 48 h, respectively. Cell growth and colony formation as well as senescence induction were quantified after treatment. Cell cycle distribution and phosphorylation of histone variant H2AX as a surrogate marker for DNA damage was quantified by flow cytometry. Relative changes in gene expression were determined by quantitative real time PCR.

Results

Prolonged pemetrexed pretreatment for 48 h prior to cisplatin treatment maximally delayed long-term cell growth and significantly reduced the number of recovering clones. Moreover, apoptosis and senescence were augmented and recovery from treatment-induced DNA damage was delayed. Interestingly, a cell population was identified that displayed an epithelial-to-mesenchymal transition (EMT) and which had a stem cell phenotype. This population was highly resistant to concomitant pemetrexed-cisplatin treatment but was sensitized by pemetrexed pretreatment.

Conclusions

Adaptation of the standard treatment schedule to include pretreatment with pemetrexed optimizes the anticancer efficiency of pemetrexed-cisplatin combination therapy, which correlates with a persistence of treatment-induced DNA damage. Therefore, this study warrants further investigations to elucidate whether such an adaptation could enhance the effectiveness of the standard clinical treatment regimen. In addition, a subpopulation of therapy resistant cells with EMT and cancer stem cell features was identified that was resistant to the standard treatment regimen but sensitive to pemetrexed pretreatment combined with cisplatin.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2117-4) contains supplementary material, which is available to authorized users.

Aurora kinase targeting in lung cancer reduces KRAS-induced transformation

BACKGROUND

Activating mutations in KRAS are prevalent in lung cancer and have been causally linked to the oncogenic process. However, therapies targeted to oncogenic RAS have been ineffective to date and identification of KRAS targets that impinge on the oncogenic phenotype is warranted. Based on published studies showing that mitotic kinases Aurora A (AURKA) and B (AURKB) cooperate with oncogenic RAS to promote malignant transformation and that AURKA phosphorylates RAS effector pathway components, the aim of this study was to investigate whether AURKA and AURKB are KRAS targets in lung cancer and whether targeting these kinases might be therapeutically beneficial.

METHODS

In order to determine whether oncogenic KRAS induces Aurora kinase expression, we used qPCR and western blotting in three different lung cell-based models of gain- or loss-of-function of KRAS. In order to determine the functional role of these kinases in KRAS-induced transformation, we generated KRAS-positive A549 and H358 cells with stable and inducible shRNA-mediated knockdown of AURKA or AURKB and evaluated transformation in vitro and tumor growth in vivo. In order to validate AURKA and/or AURKB as therapeutically relevant KRAS targets in lung cancer, we treated A549 and H358 cells, as well as two different lung cell based models of gain-of-function of KRAS with a dual Aurora kinase inhibitor and performed functional in vitro assays.

RESULTS

We determined that KRAS positively regulates AURKA and AURKB expression. Furthermore, in KRAS-positive H358 and A549 cell lines, inducible knockdown of AURKA or AURKB, as well as treatment with a dual AURKA/AURKB inhibitor, decreased growth, viability, proliferation, transformation, and induced apoptosis in vitro. In addition, inducible shRNA-mediated knockdown of AURKA in A549 cells decreased tumor growth in vivo. More importantly, dual pharmacological inhibiton of AURKA and AURKB reduced growth, viability, transformation, and induced apoptosis in vitro in an oncogenic KRAS-dependent manner, indicating that Aurora kinase inhibition therapy can specifically target KRAS-transformed cells.

CONCLUSIONS

Our results support our hypothesis that Aurora kinases are important KRAS targets in lung cancer and suggest Aurora kinase inhibition as a novel approach for KRAS-induced lung cancer therapy.

Knockdown of Aurora-B inhibits the growth of non-small cell lung cancer A549 cells

Elevated expression of Aurora-B affects cell apoptosis and proliferation in a variety of solid tumors. However, the role of Aurora-B has been poorly evaluated in non-small cell lung cancer (NSCLC). In the present study, it was found that Aurora-B was overexpressed in tissue specimens obtained from 174 patients with lung cancer. It was also demonstrated that knockdown of Aurora-B induces apoptosis and inhibits the growth of lung cancer A549 cells in vitro and in vivo. Furthermore, it was found that silencing Aurora-B decreased the activity of the phosphoinositide 3-kinase (PI3K)/AKT pathway. Therefore, it was concluded that knockdown of Aurora-B induces apoptosis and inhibits growth in NSCLC A549 cells, in addition to inhibiting the activity of the PI3K/AKT signaling pathway. Targeting Aurora-B may provide a novel target for lung cancer therapy.