Structural mechanism of synergistic activation of Aurora kinase B/C by phosphorylated INCENP

The Role and Mechanisms of Aurora Kinases in Kidney Diseases

Aurora kinases are a family of serine/threonine kinases that includes Aurora kinase A, Aurora kinase B, and Aurora kinase C. These kinases play crucial roles in mitotic spindle formation and cell proliferation. Over the past several decades, extensive research has elucidated the multifaceted roles of Aurora kinases in cancer development and progression. Recent studies have also highlighted the significant involvement of Aurora kinases in various kidney diseases, such as renal cell carcinoma, diabetic nephropathy, chronic kidney disease, and polycystic kidney disease. The mechanisms by which Aurora kinases contribute to renal diseases are complex and influenced by both specific pathological conditions and environmental factors. In this review, we comprehensively summarize the role and mechanisms through which Aurora kinases operate in kidney diseases and discuss the efficacy and application of existing inhibitors targeting these kinases in managing renal disorders in animal models.

"Exploration of Novel Anticancerous Agents Targeting Human Aurora Kinase C"

Aurora kinases (AKs), a family of serine/threonine kinases, play a vital role in chromosome segregation during the cell cycle (Mountzios et al., 2008). This family includes Aurora Kinase A (AKA), Aurora Kinase B (AKB), and Aurora Kinase C (AKC). AKA and AKB are active during mitosis, while AKC is involved mostly in germ cell as well as somatic cells. Elevated levels of AKC have been found in several cancer cell lines including breast, cervical, thyroid, colorectal, and liver cancers, making it a significant target for cancer therapy (Tang et al., 2017). In cancers such as glioblastoma and prostate cancer, for example, AKC up regulation has been associated with increased tumor aggressiveness, highlighting its potential role in tumor progression and poor prognosis. Our study employs computational methods, including molecular docking and structure-based virtual screening, to explore a data set of 2 65 241 compounds from the National Cancer Institute (NCI) database, focusing on AKC as a potential target for drug discovery. Through docking studies, several promising compounds that interact with the enzyme's ATP binding pocket, particularly with residues Phe54, Lys72, Ala123, Glu121 and Glu127 of AKC, were identified. The stability of these interactions was assessed through 200-ns molecular dynamics (MD) simulations, revealing that the majority of compounds exhibited stable interactions, while a few displayed fluctuations in their trajectories. Most compounds adhered to favorable pharmacokinetic properties. Comprehensive MD simulations and free energy calculations identified three top candidates (90 729, 37 623, and 134 546) with strong potential as potent inhibitors of AKC. Additional in vitro and in vivo studies are required to confirm the therapeutic potential of these candidates.

The functional correlation between mir-16-5p and BIRC5 gene in colorectal cancer: integrated analysis of transcriptomics and in vitro validation

BACKGROUND

This study explores the mechanisms of colorectal cancer (CRC) through bioinformatics and in vitro experiments. The goal is to find differentially expressed genes (DEGs) and miRNA-gene interactions, especially between miR-16-5p and BIRC5, in order to find biomarkers that can be used to diagnose, predict, and treat CRC.

METHODS AND RESULTS

Microarray data (GSE52060) from the GEO database was analysed using R software, applying LIMMA for log2 transformation and quantile normalization. Significant DEGs were identified, and miRNA targets were predicted with miRWalk v.3 and validated in CRC cell lines. Statistical analyses were conducted using R and GraphPad Prism. BIRC5's impact on survival was analysed via GEPIA2, and correlated genes were identified using Correlation AnalyzeR. The treatment of miR-16-5p mimic significantly reduced BIRC5 expression in HT-29, SW480, and HCT116 cells in a dose-dependent manner. Correlational analyses revealed a strong negative association between miR-16-5p levels and BIRC5 expression, emphasizing miR-16-5p's role as a tumor suppressor. While BIRC5 inhibits apoptosis and regulates cell division, miR-16-5p impacts apoptosis, the cell cycle, and angiogenesis. GEPIA2 analysis indicated that BIRC5 expression had no significant impact on CRC survival outcomes.

CONCLUSIONS

This study demonstrates miR-16-5p's regulatory role on BIRC5 in CRC cells and its therapeutic potential. Restoring miR-16-5p or targeting BIRC5 could improve CRC treatment strategies. To learn more about how miR-16-5p and BIRC5 can be used to diagnose and predict CRC, more clinical testing is needed. This will help us learn more about how CRC works at the molecular level.

Activation is only the beginning: mechanisms that tune kinase substrate specificity

Kinases are master coordinators of cellular processes, but to appropriately respond to the changing cellular environment, each kinase must recognize its substrates, target only those proteins on the correct amino acids, and in many cases, only phosphorylate a subset of potential substrates at any given time. Therefore, regulation of kinase substrate specificity is paramount to proper cellular function, and multiple mechanisms can be employed to achieve specificity. At the smallest scale, characteristics of the substrate such as its linear peptide motif and three-dimensional structure must be complementary to the substrate binding surface of the kinase. This surface is dynamically shaped by the activation loop and surrounding region of the substrate binding groove, which can adopt multiple conformations, often influenced by post-translational modifications. Domain-scale conformational changes can also occur, such as the interaction with pseudosubstrate domains or other regulatory domains in the kinase. Kinases may multimerize or form complexes with other proteins that influence their structure, function, and/or subcellular localization at different times and in response to different signals. This review will illustrate these mechanisms by examining recent work on four serine/threonine kinases: Aurora B, CaMKII, GSK3β, and CK1δ. We find that these mechanisms are often shared by this diverse set of kinases in diverse cellular contexts, so they may represent common strategies that cells use to regulate cell signaling, and it will be enlightening to continue to learn about the depth and robustness of kinase substrate specificity in additional systems.

Robust approach for production of the human oncology target Aurora kinase B in complex with its binding partner INCENP

Protein kinases are key players in many eukaryotic signal transduction cascades and are as a result often linked to human disease. In humans, the mitotic protein kinase family of Aurora kinases consist of three members: Aurora A, B and C. All three members are involved in cell division with proposed implications in various human cancers. The human Aurora kinase B has in particular proven challenging to study with structural biology approaches, and this is mainly due to difficulties in producing the large quantities of active enzyme required for such studies. Here, we present a novel and E. coli-based production system that allows for production of milligram quantities of well-folded and active human Aurora B in complex with its binding partner INCENP. The complex is produced as a continuous polypeptide chain and the resulting fusion protein is cleaved with TEV protease to generate a stable and native heterodimer of the Aurora B:INCENP complex. The activity, stability and degree of phosphorylation of the protein complex was quantified by using a coupled ATPase assay, 31P NMR spectroscopy and mass spectrometry. The developed production system enables isotope labeling and we here report the first 1H-15N-HSQC of the human Aurora B:INCENP complex. Our developed production strategy paves the way for future structural and functional studies of Aurora B and can as such assist the development of novel anticancer drugs targeting this important mitotic protein kinase.

CEP192 localises mitotic Aurora-A activity by priming its interaction with TPX2

Aurora-A is an essential cell-cycle kinase with critical roles in mitotic entry and spindle dynamics. These functions require binding partners such as CEP192 and TPX2, which modulate both kinase activity and localisation of Aurora-A. Here we investigate the structure and role of the centrosomal Aurora-A:CEP192 complex in the wider molecular network. We find that CEP192 wraps around Aurora-A, occupies the binding sites for mitotic spindle-associated partners, and thus competes with them. Comparison of two different Aurora-A conformations reveals how CEP192 modifies kinase activity through the site used for TPX2-mediated activation. Deleting the Aurora-A-binding interface in CEP192 prevents centrosomal accumulation of Aurora-A, curtails its activation-loop phosphorylation, and reduces spindle-bound TPX2:Aurora-A complexes, resulting in error-prone mitosis. Thus, by supplying the pool of phosphorylated Aurora-A necessary for TPX2 binding, CEP192:Aurora-A complexes regulate spindle function. We propose an evolutionarily conserved spatial hierarchy, which protects genome integrity through fine-tuning and correctly localising Aurora-A activity.

Successful intracytoplasmic sperm injection in a macrozoospermia case with novel compound heterozygous aurora kinase C (AURKC) mutations

PURPOSE

To explore the application possibility of macrocephalic sperm from a patient with 100% macrocephalic sperm and AURKC gene variations.

METHODS

We diagnosed a case of macrozoospermia with 100% macrocephalic sperm and 39.5% multi-tailed spermatozoa by morphological analysis. Whole-exome sequencing (WES) was used for the patient and his wife. Sanger sequencing technique was used to verify the AURKC mutations in the patient's parents and his offspring. Sperm's ploidy was tested by flow cytometry. The couple asked for intra-couple ART therapy.

RESULTS

The patient presented novel compound heterozygous AURKC mutations (c.434C > T, c.497A > T) by WES. Sanger sequencing validation showed that variant of c.434C > T was observed in his father and c.497A > T was observed in his mother. Flow cytometry revealed that there existed a certain proportion of haploid sperm. Macrocephalic spermatozoa whose heads were smaller than the diameter of injection needle were selected for microinjection. A singleton pregnancy was achieved after embryo transfer. Prenatal diagnosis revealed that the fetus had normal chromosomal karyotype. Sanger sequencing technique showed that the fetus carried a c.434C > T mutation in one AURKC allele. A 3730 g healthy male fetus was delivered at term.

CONCLUSION

Our study reported a successful live birth from a patient with definite AURKC gene variants and may provide insights for such patients to choose donor sperm or their own sperm.

Surface-mutagenesis strategies to enable structural biology crystallization platforms

A key prerequisite for the successful application of protein crystallography in drug discovery is to establish a robust crystallization system for a new drug-target protein fast enough to deliver crystal structures when the first inhibitors have been identified in the hit-finding campaign or, at the latest, in the subsequent hit-to-lead process. The first crucial step towards generating well folded proteins with a high likelihood of crystallizing is the identification of suitable truncation variants of the target protein. In some cases an optimal length variant alone is not sufficient to support crystallization and additional surface mutations need to be introduced to obtain suitable crystals. In this contribution, four case studies are presented in which rationally designed surface modifications were key to establishing crystallization conditions for the target proteins (the protein kinases Aurora-C, IRAK4 and BUB1, and the KRAS-SOS1 complex). The design process which led to well diffracting crystals is described and the crystal packing is analysed to understand retrospectively how the specific surface mutations promoted successful crystallization. The presented design approaches are routinely used in our team to support the establishment of robust crystallization systems which enable structure-guided inhibitor optimization for hit-to-lead and lead-optimization projects in pharmaceutical research.

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.

Revisiting Aurora Kinase B: A promising therapeutic target for cancer therapy

Cancer continues to be a major health concern globally, although the advent of targeted therapy has revolutionized treatment options. Aurora Kinase B is a serine-threonine kinase that has been explored as an oncology therapeutic target for more than two decades. Aurora Kinase B inhibitors show promising biological results in in-vitro and in-vivo experiments. However, there are no inhibitors approved yet for clinical use, primarily because of the side effects associated with Aurora B inhibitors. Several studies demonstrate that Aurora B inhibitors show excellent synergy with various chemotherapeutic agents, radiation therapy, and targeted therapies. This makes it an excellent choice as an adjuvant therapy to first-line therapies, which greatly improves the therapeutic window and side effect profile. Recent studies indicate the role of Aurora B in some deadly cancers with limited therapeutic options, like triple-negative breast cancer and glioblastoma. Herein, we review the latest developments in Aurora Kinase B targeted research, with emphasis on its potential as an adjuvant therapy and its role in some of the most difficult-to-treat cancers.

Functional specialization of Aurora kinase homologs during oogenic meiosis in the tunicate Oikopleura dioica

A single Aurora kinase found in non-vertebrate deuterostomes is assumed to represent the ancestor of vertebrate Auroras A/B/C. However, the tunicate Oikopleura dioica, a member of the sister group to vertebrates, possesses two Aurora kinases (Aurora1 and Aurora2) that are expressed in proliferative cells and reproductive organs. Previously, we have shown that Aurora kinases relocate from organizing centers to meiotic nuclei and were enriched on centromeric regions as meiosis proceeds to metaphase I. Here, we assessed their respective functions in oogenic meiosis using dsRNA interferences. We found that Aurora1 (Aur1) was involved in meiotic spindle organization and chromosome congression, probably through the regulation of microtubule dynamics, whereas Aurora2 (Aur2) was crucial for chromosome condensation and meiotic spindle assembly. In vitro kinase assays showed that Aur1 and Aur2 had comparable levels of kinase activities. Using yeast two-hybrid library screening, we identified a few novel interaction proteins for Aur1, including c-Jun-amino-terminal kinase-interacting protein 4, cohesin loader Scc2, and mitochondrial carrier homolog 2, suggesting that Aur1 may have an altered interaction network and participate in the regulation of microtubule motors and cohesin complexes in O. dioica.

Computational study of the potential impact of AURKC missense SNPs on AURKC-INCENP interaction and their correlation to macrozoospermia

Aurora Kinase C (AURKC) is considered an important element in Chromosome Passenger Complex (CPC), its interaction with Inner Centromere Protein (INCENP) plays a critical role in the establishment and the recruitment of a stable CPC during spermatogenesis. Genetic variations of AURKC gene are susceptible to impact AURKC-INCENP interaction, which may affect CPC stability and predispose male subjects to macrozoospermia. In this study, we systematically applied computational approaches using different bioinformatic tools to predict the effect of missense SNPs reported on AURKC gene, we selected the deleterious ones and we introduced their corresponding amino acid substitutions on AURKC protein structure. Then we did a protein-protein docking between AURKC variants and INCENP followed by a structural assessment of each resulting complex using PRODIGY server, Yassara view, Ligplot + and we choose the complexes of the most impactful variants for molecular dynamics (MD) simulation study. Seventeen missense SNPs of AURKC were identified as deleterious between all reported ones. All of them were located on relatively conserved positions on AURKC protein according to Consurf server. Only the four missense SNPs; E91K, D166V, D221Y and G235V were ranked as the most impactful ones and were chosen for MD simulation. D221Y and G235V were responsible for the most remarkable changes on AURKC-INCENP structural stability, therefore, they were selected as the most deleterious ones. Experimental studies are recommended to test the actual effect of these two variants and their actual impact on the morphology of sperm cells.Communicated by Ramaswamy H. Sarma.

FREEDA: An automated computational pipeline guides experimental testing of protein innovation

Cell biologists typically focus on conserved regions of a protein, overlooking innovations that can shape its function over evolutionary time. Computational analyses can reveal potential innovations by detecting statistical signatures of positive selection that lead to rapid accumulation of beneficial mutations. However, these approaches are not easily accessible to non-specialists, limiting their use in cell biology. Here, we present an automated computational pipeline FREEDA that provides a simple graphical user interface requiring only a gene name; integrates widely used molecular evolution tools to detect positive selection in rodents, primates, carnivores, birds, and flies; and maps results onto protein structures predicted by AlphaFold. Applying FREEDA to >100 centromere proteins, we find statistical evidence of positive selection within loops and turns of ancient domains, suggesting innovation of essential functions. As a proof-of-principle experiment, we show innovation in centromere binding of mouse CENP-O. Overall, we provide an accessible computational tool to guide cell biology research and apply it to experimentally demonstrate functional innovation.

Src inhibition induces mitotic arrest associated with chromosomal passenger complex

The non-receptor tyrosine kinase Src plays a key role in cell division, migration, adhesion, and survival. Src is overactivated in several cancers, where it transmits signals that promote cell survival, mitosis, and other important cancer hallmarks. Src is therefore a promising target in cancer therapy, but the underlying mechanisms are still uncertain. Here we show that Src is highly conserved across different species. Src expression increases during mitosis and is localized to the chromosomal passenger complex. Knockdown or inhibition of Src induces multipolar spindle formation, resulting in abnormal expression of the Aurora B and INCENP components of the chromosomal passenger complex. Molecular mechanism studies have found that Src interacts with and phosphorylates INCENP. This then leads to incorrect chromosome arrangement and segregation, resulting in cell division failure. Herein, Src and chromosomal passenger complex co-localize and Src inhibition impedes mitotic progression by inducing multipolar spindle formation. These findings provide novel insights into the molecular basis for using Src inhibitors to treat cancer.

Structural basis for CEP192-mediated regulation of centrosomal AURKA

Aurora kinase A (AURKA) performs critical functions in mitosis. Thus, the activity and subcellular localization of AURKA are tightly regulated and depend on diverse factors including interactions with the multiple binding cofactors. How these different cofactors regulate AURKA to elicit different levels of activity at distinct subcellular locations and times is poorly understood. Here, we identified a conserved region of CEP192, the major cofactor of AURKA, that mediates the interaction with AURKA. Quantitative binding studies were performed to map the interactions of a conserved helix (Helix-1) within CEP192. The crystal structure of Helix-1 bound to AURKA revealed a distinct binding site that is different from other cofactor proteins such as TPX2. Inhibiting the interaction between Helix-1 and AURKA in cells led to the mitotic defects, demonstrating the importance of the interaction. Collectively, we revealed a structural basis for the CEP192-mediated AURKA regulation at the centrosome, which is distinct from TPX2-mediated regulation on the spindle microtubule.

FREEDA: an automated computational pipeline guides experimental testing of protein innovation by detecting positive selection

Cell biologists typically focus on conserved regions of a protein, overlooking innovations that can shape its function over evolutionary time. Computational analyses can reveal potential innovations by detecting statistical signatures of positive selection that leads to rapid accumulation of beneficial mutations. However, these approaches are not easily accessible to non-specialists, limiting their use in cell biology. Here, we present an automated computational pipeline FREEDA (Finder of Rapidly Evolving Exons in De novo Assemblies) that provides a simple graphical user interface requiring only a gene name, integrates widely used molecular evolution tools to detect positive selection, and maps results onto protein structures predicted by AlphaFold. Applying FREEDA to >100 mouse centromere proteins, we find evidence of positive selection in intrinsically disordered regions of ancient domains, suggesting innovation of essential functions. As a proof-of-principle experiment, we show innovation in centromere binding of CENP-O. Overall, we provide an accessible computational tool to guide cell biology research and apply it to experimentally demonstrate functional innovation.

The ubiquitin-ligase TRAF6 and TGFβ type I receptor form a complex with Aurora kinase B contributing to mitotic progression and cytokinesis in cancer cells

Background

Transforming growth factor β (TGFβ) is overexpressed in several advanced cancer types and promotes tumor progression. We have reported that the intracellular domain (ICD) of TGFβ receptor (TβR) I is cleaved by proteolytic enzymes in cancer cells, and then translocated to the nucleus in a manner dependent on the endosomal adaptor proteins APPL1/2, driving an invasiveness program. How cancer cells evade TGFβ-induced growth inhibition is unclear.

Methods

We performed microarray analysis to search for genes regulated by APPL1/2 proteins in castration-resistant prostate cancer (CRPC) cells. We investigated the role of TβRI and TRAF6 in mitosis in cancer cell lines cultured in 10% FBS in the absence of exogenous TGFβ. The molecular mechanism of the ubiquitination of AURKB by TRAF6 in mitosis and the formation of AURKB–TβRI complex in cancer cell lines and tissue microarrays was also studied.

Findings

During mitosis and cytokinesis, AURKB–TβRI complexes formed in midbodies in CRPC and KELLY neuroblastoma cells. TRAF6 induced polyubiquitination of AURKB on K85 and K87, protruding on the surface of AURKB to facilitate its activation. AURKB–TβRI complexes in patient's tumor tissue sections correlated with the malignancy of prostate cancer.

Interpretation

The AURKB–TβRI complex may become a prognostic biomarker for patients with risk of developing aggressive PC.

Funding

Swedish Medical Research Council (2019-01598, ML; 2015-02757 and 2020-01291, CHH), the Swedish Cancer Society (20 0964, ML), a regional agreement between Umeå University and Region Västerbotten (ALF; RV-939377, -967041, -970057, ML). The European Research Council (787472, CHH). KAW 2019.0345, and the Kempe Foundation SMK-1866; ML. National Microscopy Infrastructure (NMI VR-RFI 2016-00968).

High-Resolution Native Mass Spectrometry

Native mass spectrometry (MS) involves the analysis and characterization of macromolecules, predominantly intact proteins and protein complexes, whereby as much as possible the native structural features of the analytes are retained. As such, native MS enables the study of secondary, tertiary, and even quaternary structure of proteins and other biomolecules. Native MS represents a relatively recent addition to the analytical toolbox of mass spectrometry and has over the past decade experienced immense growth, especially in enhancing sensitivity and resolving power but also in ease of use. With the advent of dedicated mass analyzers, sample preparation and separation approaches, targeted fragmentation techniques, and software solutions, the number of practitioners and novel applications has risen in both academia and industry. This review focuses on recent developments, particularly in high-resolution native MS, describing applications in the structural analysis of protein assemblies, proteoform profiling of─among others─biopharmaceuticals and plasma proteins, and quantitative and qualitative analysis of protein-ligand interactions, with the latter covering lipid, drug, and carbohydrate molecules, to name a few.

Using ZINC08918027 inhibitor to determine Aurora kinase-chromosomal passenger complex isoforms in mouse oocytes

Objective

Miscarriages affect 10% of women aged 25–29, and 53% of women over 45. The primary cause of miscarriage is aneuploidy that originated in eggs. The Aurora kinase family has three members that regulate chromosome segregation. Therefore, distinguishing the roles of these isoforms is important to understand aneuploidy etiology. In meiosis, Aurora kinase A (AURKA) localizes to spindle poles, where it binds TPX2. Aurora kinase C (AURKC) localizes on chromosomes, where it replaces AURKB as the primary AURK in the chromosomal passenger complex (CPC) via INCENP binding. Although AURKA compensates for CPC function in oocytes lacking AURKB/C, it is unknown whether AURKA binds INCENP in wild type mouse oocytes. ZINC08918027 (ZC) is an inhibitor that prevents the interaction between AURKB and INCENP in mitotic cells. We hypothesized that ZC would block CPC function of any AURK isoform.

Results

ZC treatment caused defects in meiotic progression and spindle building. By Western blotting and immunofluorescence, we observed that activated AURKA and AURKC levels in ZC-treated oocytes decreased compared to controls. These results suggest there is a population of AURKA-CPC in mouse oocytes. These data together suggest that INCENP-dependent AURKA and AURKC activities are needed for spindle bipolarity and meiotic progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-022-05987-4.

Identification of polypharmacological anticancerous molecules against Aurora kinase family of proteins

The Human Aurora Kinase (AURK) protein family is the key player of cell cycle events including spindle assembly, kinetochore formation, chromosomal segregation, centrosome separation, microtubule dynamics, and cytokinesis. Their aberrant expression has been extensively linked with chromosomal instability in addition to derangement of multiple tumor suppressors and oncoprotein regulated pathways. Therefore, the AURK family of kinases is a promising target for the treatment of various types of cancer. Over the past few decades, several potential inhibitors of AURK proteins have been identified and have reached various phases of clinical trials. But very few molecules have currently crossed the safety criteria due to their various toxic side effects. In the present study, we have adopted a computational polypharmacological strategy and identified four novel molecules that can target all three AURKs. These molecules were further investigated for their binding stabilities at the ATP binding pocket using molecular dynamics based simulation studies. The molecules selected adopting a multipronged computational approach can be considered as potential AURKs inhibitors for cancer therapeutics.

An Integrated Deep Learning and Molecular Dynamics Simulation-Based Screening Pipeline Identifies Inhibitors of a New Cancer Drug Target TIPE2

The TIPE2 (tumor necrosis factor-alpha-induced protein 8-like 2) protein is a major regulator of cancer and inflammatory diseases. The availability of its sequence and structure, as well as the critical amino acids involved in its ligand binding, provides insights into its function and helps greatly identify novel drug candidates against TIPE2 protein. With the current advances in deep learning and molecular dynamics simulation-based drug screening, large-scale exploration of inhibitory candidates for TIPE2 becomes possible. In this work, we apply deep learning-based methods to perform a preliminary screening against TIPE2 over several commercially available compound datasets. Then, we carried a fine screening by molecular dynamics simulations, followed by metadynamics simulations. Finally, four compounds were selected for experimental validation from 64 candidates obtained from the screening. With surprising accuracy, three compounds out of four can bind to TIPE2. Among them, UM-164 exhibited the strongest binding affinity of 4.97 µM and was able to interfere with the binding of TIPE2 and PIP2 according to competitive bio-layer interferometry (BLI), which indicates that UM-164 is a potential inhibitor against TIPE2 function. The work demonstrates the feasibility of incorporating deep learning and MD simulation in virtual drug screening and provides high potential inhibitors against TIPE2 for drug development.

Bora phosphorylation substitutes in trans for T-loop phosphorylation in Aurora A to promote mitotic entry

Polo-like kinase 1 (Plk1) is instrumental for mitotic entry and progression. Plk1 is activated by phosphorylation on a conserved residue Thr210 in its activation segment by the Aurora A kinase (AURKA), a reaction that critically requires the co-factor Bora phosphorylated by a CyclinA/B-Cdk1 kinase. Here we show that phospho-Bora is a direct activator of AURKA kinase activity. We localize the key determinants of phospho-Bora function to a 100 amino acid region encompassing two short Tpx2-like motifs and a phosphoSerine-Proline motif at Serine 112, through which Bora binds AURKA. The latter substitutes in trans for the Thr288 phospho-regulatory site of AURKA, which is essential for an active conformation of the kinase domain. We demonstrate the importance of these determinants for Bora function in mitotic entry both in Xenopus egg extracts and in human cells. Our findings unveil the activation mechanism of AURKA that is critical for mitotic entry.

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.

Phase Separation in Cell Division

Cell division requires the assembly and organization of a microtubule spindle for the proper separation of chromosomes in mitosis and meiosis. Phase separation is an emerging paradigm for understanding spatial and temporal regulation of a variety of cellular processes, including cell division. Phase-separated condensates have been recently discovered at many structures during cell division as a possible mechanism for properly localizing, organizing, and activating proteins involved in cell division. Here, we review how these condensates play roles in regulating microtubule density and organization and spindle assembly and function and in activating some of the key players in cell division. We conclude with perspectives on areas of future research for this exciting and rapidly advancing field.

Compound heterozygosity for novel AURKC mutations in an infertile man with macrozoospermia

Among causes of infertility, teratozoospermia is characterised by a percentage of morphologically abnormal spermatozoa >4%. Macrozoospermia, one form of monomorphic teratozoospermia, is observed in <1% of cases of male infertility and is described as approximately 100% large-headed and/or multitailed spermatozoa. This study reports that an infertile man with large-head spermatozoa presenting compound heterozygosity aurora kinase C (AURKC) mutations (c.382C>T, c.572C>T) by whole-exome sequencing. Consequently, both two novel AURKC mutations had high probability of damage-causing and conserved across species and extremely low allele frequency in the population. Flow cytometry analysis revealed a high ratio of sperm DNA fragmentation. Two intracytoplasmic sperm injection (ICSI) procedures were attempted for the patient, but all were unsuccessful. These results indicate that sequence analysis should be performed for the variants of AURKC in Chinese patients with macrozoospermia.

Aurora A inhibition disrupts chromosome condensation and spindle assembly during the first embryonic division in pigs

As common overexpression of Aurora A in various tumours, much attention has focused on its function in inducing cancer, and its value in cancer therapeutics, considerably less is known regarding its role in the first cleavage division of mammalian embryos. Here, we highlight an indispensable role of Aurora A during the first mitotic division progression of pig embryos just after meiosis. The expression and spatiotemporal localization of Aurora A were initially assessed in pig embryos during the first mitotic division by Western blot analysis and indirect immunofluorescent staining. Then, the potential role of Aurora A was further evaluated using a highly selective Aurora A inhibitor, MLN8054, during this mitotic progression in pig embryos. Aurora A was found to express and exhibit a specific dynamic intracellular localization pattern during the first mitotic division in pig embryos. Aurora A was diffused in the cytoplasm at the prophase stage, and then exhibited a dynamic intracellular localization which was tightly associated with the chromosome and spindle dynamics throughout subsequent mitotic phases. Inhibition of Aurora A by MLN8054 treatment led to the failure of the first cleavage, with the majority of embryos being arrested in prophase of the mitotic division. Further subcellular structure examination showed that Aurora A inhibition not only led to the failure of spindle microtubule assembly, but also resulted in severe defects in chromosome condensation, accompanied by an obvious decrease in p-TACC3(S558) expression during the prophase of the first mitosis. Together, these results illustrated that Aurora A is crucial for both spindle assembly and chromosome condensation during the first mitotic division in pig embryos, and that the regulation of Aurora A may be associated with its effects on p-TACC3(S558) expression.