Overexpression Of Aurora Kinase A Research Articles

Extracellular mechanical forces and ferroptosis in triple negative breast cancer (TNBC): Targeting of aurora kinase A (AURKA).

e13086 Background: The mechanics of tumor microenvironment, primarily induced by extracellular matrix (ECM), function to regulate cell biological behaviors. However, it is unclear if and how triple negative breast cancer (TNBC) cells adapt their biological characteristics to variable extracellular mechanical forces. Methods: TNBC tissues of different stiffness from patients were harvested for untargeted metabolomics to investigate the potential effects of mechanical forces on metabolism. TNBC cells were cultured within gels of different type I collagen (Col-I) densities, which were the major component of ECM, to simulate the effects of extracellular mechanical forces on cells. The metabolic changes of TNBC cells were also examined by using untargeted metabolomics. TNBC cells bathed in different Col-I densities were injected subcutaneously into the breast pad of nude mice. Ferroptosis indicators were evaluated between different groups of mechanical force both in vitro and in vivo. Real-time quantitative polymerase chain reaction (RT-qPCR) and western blot were carried out to examine the expression of ferroptosis-related genes and proteins between different groups of mechanical force. Results: Untargeted metabolomics studies showed significant differences in ferroptosis-related metabolites between TNBC tissues with different stiffness, which were also verified in TNBC cells subjected to different extracellular mechanical forces. In vitro experiment suggested that TNBC cells cultured within high Col-I density (strong extracellular forces) exhibited higher levels of lipid peroxidation, reactive oxygen accumulation, mitochondria membrane potential and iron concentration, and lower levels of total glutathione and reduced glutathione concentration, compared with low Col-I density (weak extracellular forces). In addition, mitochondria in high Col-I density group appeared to have volume decrease, fracture and fuzzy cristae. The above results indicated that extracellular mechanical force significantly induced ferroptosis in TNBC. RT-qPCR and western blot of ferroptosis-related genes and protein showed that both mRNA and protein levels of aurora kinase A (AURKA) were significantly decreased in TNBC cells with strong extracellular mechanical force. In addition, overexpression of AURKA inhibited ferroptosis caused by mechanical forces. Furthermore, this cause and effect among mechanical force, AURKA and ferroptosis was also evident in vivo experiments. Conclusions: Our data clarified the role of extracellular mechanical forces in TNBC and showed that the extracellular mechanical forces induced ferroptosis through decreasing the expression of AURKA.

Abstract 542: Synthetic lethal targeting of AURKA in head and neck squamous cell carcinoma

Abstract The purpose of this study was to identify new combination strategies for improving treatment of head and neck squamous cell carcinomas (HNSCCs). HNSCCs often express high levels of Aurora kinase A (AURKA), most studied as a kinase important for mitotic progression in normal cells. Notably the overexpression of AURKA in many cancers allows it to act throughout the cell cycle, acquiring new cancer-promoting activities. While several AURKA inhibitors are in clinical trials, limited efficacy is observed with single treatment, causing us to evaluate potential AURKA combination therapeutic combinations. Particularly relevant to HNSCC, which often overexpress and depend on EGFR, overexpression of AURKA can promote resistance to EGFR inhibitors by mechanisms variously identified as including activation of the EGFR effectors AKT, ERK, and BIM. Using viability and clonogenic assays, we have found that the AURKA inhibitor VIC-1911 synergizes with the EGFR inhibitors afatinib and erlotinib in multiple HNSCC cell lines and retains activity in HNSCC cell models selected for resistance to these EGFR inhibitors. However, AURKA inhibition increases levels of AURKA protein and its protein-stabilizing partner TPX2, counteracting drug effect. We also combined inhibition of AURKA with inhibition of WEE1, a regulator of the G2/M checkpoint, finding this dual inhibition enhanced levels of apoptosis in EGFR inhibitor resistant HNSCC cell lines. Intriguingly, one recent study reported AURKA can also modulate the glycolytic signaling pathway, increasing the cancer-promoting Warburg effect. We have found that inhibition of AURKA can significantly reduce glycolytic flux in HNSCC cell lines and alter expression and phosphorylation of key glycolytic enzymes. Dual inhibition of AURKA in combination with inhibitors of glycolytic enzymes, or enzymes regulating oxidative phosphorylation, showed marked synergy. These and other results investigating AURKA signaling mechanisms in HNSCC demonstrate that the non-canonical functions of AURKA include viable therapeutic targets that can enhance the efficacy of AURKA inhibition in HNSCC. Citation Format: Flaviane N da Silva, Theodore Nguyen, Jong Woo Lee, Barbara Burtness, Erica Golemis. Synthetic lethal targeting of AURKA in head and neck squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 542.

Cell cycle kinases (AUKA, CDK1, PLK1) are prognostic biomarkers and correlated with tumor-infiltrating leukocytes in HBV related HCC

Hepatocellular carcinoma (HCC) is one of the high incidence cancers and third leading cause of cancer-related mortality. HBV is the top most risk factor accounting for 50–80% of the HCC cases. Kinases: Aurora kinase A (AURKA), cyclin-dependent kinase (CDK1) and Polo-like kinase 1 (PLK1), the key regulators of cell mitosis are overexpressed in varieties of cancers including HCC. However, the exact role of these genes in prognosis of HCC is not fully unveiled. In addition, there is no such an accurate prognostic biomarker for HBV-related HCC. To address this issue, we performed a multidimensional analysis of AURKA, CDK1 and PLK1 with a series of publicly available databases in multiple cancers and with experimental validation in HBV-related HCC tissues. Overexpression of AURKA, CDK1 and PLK1 was found in multiple cancers including HCC. Elevated expression of these genes could result from lowered DNA methylation and genomic alterations. Transcriptional overexpression was significantly correlated with poor prognosis of HCC patients. The expression levels were also significantly positively associated with tumor grades and stages. Furthermore, the expression levels of these genes had a strong correlation with infiltration of immune cells. Our analysis shows that AURKA, CDK1 and PLK1 are correlated with immune infiltration and are the prognostic biomarkers for HBV-induced HCC. Communicated by Ramaswamy H. Sarma

Natural anthraquinone compound emodin as a novel inhibitor of aurora A kinase: A pilot study.

Aurora kinase A (AURKA) carries out an essential role in proliferation and involves in cisplatin resistance in various cancer cells. Overexpression of AURKA is associated with the poor prognosis of cancer patients. Thus, AURKA has been considered as a target for cancer therapy. Developing AURKA inhibitors became an important issue in cancer therapy. A natural compound emodin mainly extracted from rhubarbs possesses anti-cancer properties. However, the effect of emodin on AURKA has never been investigated. In the present study, molecular docking analysis indicated that emodin interacts with AURKA protein active site. We also found nine emodin analogues from Key Organic database by using ChemBioFinder software. Among that, one analogue 8L-902 showed a similar anti-cancer effect as emodin. The bindings of emodin and 8L-902 on AURKA protein were confirmed by cellular thermal shift assay. Furthermore, emodin inhibited the AURKA kinase activity in vitro and enhanced the cisplatin-DNA adduct level in a resistant ovarian cancer cell line. It seems that emodin may have the potential to inhibit cancer cell growth and enhance cisplatin therapy in cancer with resistance. Collectively, our finding reveals a novel AURKA inhibitor, emodin, which may be vulnerable to ovarian cancer therapy in the future.

Aurora kinase A (AURKA) promotes the progression and imatinib resistance of advanced gastrointestinal stromal tumors

BackgroundGastrointestinal stromal tumor (GIST) is a common tumor that originates from the alimentary system mesenchyme. Compared to typical gastrointestinal carcinomas, GISTs exhibit unique malignant behaviors. Bioinformatic tools and subsequent experiments were applied to investigate novel targets involved in GIST progression and imatinib resistance.MethodsDifferences in gene expression profiles between advanced and nonadvanced GISTs were comprehensively analyzed based on the Gene Expression Omnibus (GEO) dataset GSE136755. A protein–protein interaction (PPI) network was constructed to identify the potential target gene. Gene set enrichment analysis (GSEA) was used to elucidate relevant biological events related to the target gene based on the GSE47911 dataset. Subsequently, immunohistochemistry and Kaplan–Meier analysis were performed to validate the prognostic value of the target gene in GISTs. Overexpression of the target gene was conducted to analyze its function in the proliferation, apoptosis, and imatinib resistance of GIST/T1 cells.ResultsIn the current study, a total of 606 differentially expressed genes (DEGs) were screened based on the GSE136755 dataset, and the upregulated DEGs in advanced GISTs were mainly involved in cell division through functional annotations. The intersecting hub gene, Aurora kinase A (AURKA), was identified by degree and bottleneck algorithms. GSEA revealed that AURKA was involved in cell cycle-related biological processes. Analysis of the Oncomine and GEPIA databases revealed a pattern of elevated AURKA expression in most human malignances. Clinical assays demonstrated that AURKA could be an independent prognostic factor for GISTs. Additionally, overexpression of AURKA was experimentally demonstrated to promote cell proliferation, inhibit cell apoptosis, and enhance imatinib resistance in GIST/T1 cells.ConclusionsThese findings indicated that overexpression of AURKA promoted GIST progression and enhanced imatinib resistance, implying that AURKA is a potential therapeutic target for GISTs.

Palmatine induces G2/M phase arrest and mitochondrial-associated pathway apoptosis in colon cancer cells by targeting AURKA

Studies have shown that palmatine (PAL) has anti-cancer effects. However, the activity and potential mechanisms of PAL against colorectal cancer remain elusive. The results showed that PAL significantly inhibited the proliferation of colon cancer cells in vitro and in vivo without significant effect on non-tumorigenic colon cells. Target prediction and clinical sample database analysis suggested that PAL may contribute to colon cancer cells phase arrest and apoptosis by targeting aurora kinase A (AURKA). Inhibition and overexpression of AURKA proved that PAL induces G2/M phase arrest and apoptosis in colon cancer cells by targeting AURKA. Moreover, PAL promoted intracellular Reactive oxygen species (ROS) production and decreased mitochondrial membrane potential (ΔΨm). PAL reduced the levels of AURKA, Bcl-xl and Bcl2 proteins, and promoted the expression of pro-apoptotic proteins P53, P73, Caspase3 and Caspase9, as well as the increase of cytochrome c (cyt. c) in cell lysates in vitro and in vivo. Together, our study confirmed that PAL induced G2/M phase arrest and mitochondrial-associated pathway apoptosis in colon cancer cells by targeting AURKA. PAL may provide a novel solution for the treatment of colon cancer by serving as a new AURKA inhibitor.

Cinobufagin Triggers Defects in Spindle Formation and Cap-Dependent Translation in Liver Cancer Cells by Inhibiting the AURKA-mTOR-eIF4E Axis.

Cinobufagin is a Na+/K+-ATPase (NKA) inhibitor with excellent anticancer effects to prolong the survival of patients. The purpose of the present study was to clarify the underlying mechanism of the anticancer effects of cinobufagin using overexpression or inhibition of aurora kinase A (AURKA) signaling. First, high expression of Na+/K+-ATPase alpha 1 subunit (ATP1A1) and AURAK resulted in increased malignant transformation in hepatocellular carcinoma (HCC) patients using the cancer genome atlas (TCGA) data and tissue samples. After treatment with cinobufagin, we successfully screened 202, 249, and 335 changing expression proteins in Huh-7 cells under normal, overexpression, and inhibition of AURKA using tandem mass tags (TMT)-labeled quantitative proteomics coupled to 2D liquid chromatography-tandem mass spectrometry (LC-MS/MS). Bioinformatics analysis revealed that these molecules were closely associated with chromosome segregation, DNA damage, and regulation of translation processes. We further confirmed that cinobufagin induced DNA damage and chromosome segregation disorders and suppresses translational processing in oncogenes by decreasing the expression of AURKA, mechanistic target of rapamycin kinase (mTOR), p-mTOR, p-extracellular regulated protein kinases (ERK), eukaryotic translation initiation factor 4E (eIF4E), and p-eIF4E, while increasing the expression of p-eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1) (S65, T37, T46, T45) and increasing the interaction between eIF4 and 4E-BP1. Our results suggested that cinobufagin performed an antitumor effects in liver cancer cells by inhibiting the AURKA-mTOR-eIF4E axis.

Epigenetic regulation of AURKA by miR-4715-3p in upper gastrointestinal cancers

Aurora kinase A (AURKA) is frequently overexpressed in several cancers. miRNA sequencing and bioinformatics analysis indicated significant downregulation of miR-4715-3p. We found that miR-4715-3p has putative binding sites on the 3UTR region of AURKA. Upper gastrointestinal adenocarcinoma (UGC) tissue samples and cell models demonstrated significant overexpression of AURKA with downregulation of miR-4715-3p. Luciferase reporter assays confirmed binding of miR-4715-3p on the 3UTR region of AURKA. miR-4715-3p mediated a reduction in AURKA levels leading to G2/M delay, chromosomal polyploidy, and cell death. We also detected a remarkable decrease in GPX4, an inhibitor of ferroptosis, with an increase in cleaved PARP and caspase-3. Inhibition of AURKA using siRNA produced similar results, suggesting a possible link between AURKA and GPX4. Analysis of UGC samples and cell models demonstrated increased methylation levels of several CpG nucleotides upstream of miR-4715-3p. 5-Aza-2′-deoxycytidine induced demethylation of several CpG nucleotides, restoring miR-4715-3p expression, leading to downregulation of AURKA. In conclusion, our data identified a novel epigenetic mechanism mediating silencing of miR-4715-3p and induction of AURKA in UGCs. Inhibition of AURKA or reconstitution of miR-4715-3p inhibited GPX4 and induced cell death, suggesting a link between AURKA and ferroptosis.

The anticancer effects of cinobufagin on hepatocellular carcinoma Huh‑7cells are associated with activation of the p73 signaling pathway.

The Na+/K+-ATPase inhibitor cinobufagin exhibits numerous anticancer effects on hepatocellular carcinoma (HCC) cells expressing wild-type p53 via inhibition of aurora kinase A (AURKA) and activation of p53 signaling. However, the effects of cinobufagin on HCC cells expressing mutant p53 remain unclear. In the present study, the anticancer effects of cinobufagin were investigated on HCC Huh-7 cells with mutant p53, and the effects of AURKA overexpression or inhibition on the anticancer effects of cinobufagin were analyzed. Viability, cell cycle progression and apoptosis of cells were determined using an MTT assay, flow cytometry and Hoechst 33342 staining, respectively. The expression levels of p53 and p73 signaling-associated proteins were investigated via western blot analysis. The results demonstrated that the expression levels of AURKA, B-cell lymphoma 2 (Bcl-2), cyclin-dependent kinase 1, cyclin B1, proliferating cell nuclear antigen and heterogeneous nuclear ribonucleoprotein K, as well as the phosphorylation of p53 and mouse double minute 2 homolog, were significantly decreased in Huh-7 cells treated with 5 µmol/l cinobufagin for 24 h. Conversely, the expression levels of Bcl-2-associated X protein, p21, p53 upregulated modulator of apoptosis and phorbol-12-myristate-13-acetate-induced protein 1, were significantly increased by cinobufagin treatment. Overexpression or inhibition of AURKA suppressed or promoted the anticancer effects of cinobufagin on Huh-7 cells, respectively. These results indicated that cinobufagin may induce anticancer effects on Huh-7 cells via the inhibition of AURKA and p53 signaling, and via the activation of p73 signaling, in an AURKA-dependent manner.

Effects of AURKA-mediated degradation of SOD2 on mitochondrial dysfunction and cartilage homeostasis in osteoarthritis.

This study aimed to investigate the mechanism of the ubiquitinase Aurora kinase A (AURKA) in the occurrence of osteoarthritis (OA) by mediating mitochondrial stress. Bioinformatic predictions revealed 2247 differentially expressed genes (DEGs) in the normal and OA tissues. According to the UbiNet database, 39 DEGs that code for ubiquitination enzymes was screened. AURKA was highly expressed in OA tissues and cells. AURKA interference inhibited the elevation of matrix metalloproteinase-13 (MMP-13). (MMP13), sex determining region Y-box 9 (Sox9), and a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS5) expression and the reduction of collagen type IIα (Col2a1) and Aggrecan expression in interleukin-1 β (IL-1β) induced chondrocytes. The animal experiments proved that depleting AURKA could repress the occurrence of OA. Superoxide dismutase 2 (SOD2) was determined to be AURKA ubiquitination substrate via AURKA expression and bioinformatic prediction experiments. SOD2 expression was lower in OA tissues, but higher in normal joint tissues. AURKA interference activates SOD2. Meanwhile, the IP results confirmed that AURKA could bind to SOD2 and degrade it through K48 ubiquitination. Modification and overexpression of AURKA reduce SOD2 levels. AURKA interference can reverse the reactive oxygen species elevation caused by SOD2 overexpression or lysine-48 (K48) mutation, respectively, leading to mitochondrial dysfunction. Furthermore, AURKA silencing suppressed the occurrence of OA induced by mitochondrial activation. These findings suggest that ubiquitination of AURKA lowers SOD2 expression and affects mitochondrial dysfunction to repress the occurrence of OA. The results of the current study reveal that AURKA ubiquitination influences mitochondrial dysfunction and suppresses the occurrence of OA via degradation of SOD2. These data reveal novel potential targets for OA treatment.

Inhibition of AURKA Reduces Proliferation and Survival of Gastrointestinal Cancer Cells With Activated KRAS by Preventing Activation of RPS6KB1

Activation of KRAS signaling and overexpression of the aurora kinase A (AURKA) are often detected in luminal gastrointestinal cancers. We investigated regulation of ribosomal protein S6 kinase B1 (RPS6KB1) by AURKA and the effects of alisertib, an AURKA inhibitor, in mice xenograft tumors grown from human gastrointestinal cancer cells with mutant, activated forms of KRAS. We tested the effects of alisertib or AURKA overexpression or knockdown in 10 upper gastrointestinal or colon cancer cell lines with KRAS mutations or amplifications using the CellTiter-Glo luminescence and clonogenic cell survival assays. We used the proximity ligation in situ assay to evaluate protein co-localization and immunoprecipitation to study protein interactions. Nude mice with xenograft tumors grown from HCT116, SNU-601, SW480, or SNU-1 cells were given oral alisertib (40 mg/kg, 5 times/wk) for 4 weeks. Tumor samples were collected and analyzed by immunoblots and immunohistochemistry. Tissue microarrays from 151 paraffin-embedded human colon tumors, with adjacent normal and adenoma tissues, were analyzed by immunohistochemistry for levels of AURKA. Alisertib reduced proliferation and survival of the cell lines tested. AURKA knockdown or inhibition with alisertib reduced levels of phosphorylated RPS6KB1 (at T389) and increased levels of proteins that induce apoptosis, including BIM, cleaved PARP, and cleaved caspase 3. AURKA co-localized and interacted with RPS6KB1, mediating RPS6KB1 phosphorylation at T389. We detected AURKA-dependent phosphorylation of RPS6KB1 in cell lines with mutations in KRAS but not in cells with wild-type KRAS. Administration of alisertib to mice with xenograft tumors significantly reduced tumor volumes (P < .001). Alisertib reduced phosphorylation of RPS6KB1 and Ki-67 and increased levels of cleaved caspase 3 in tumor tissues. In analyses of tissue microarrays, we found significant overexpression of AURKA in gastrointestinal tumor tissues compared with non-tumor tissues (P= .0003). In studies of gastrointestinal cancer cell lines with activated KRAS, we found AURKA to phosphorylate RPS6KB1, promoting cell proliferation and survival and growth of xenograft tumors in mice. Agents that inhibit AURKA might slow the growth of gastrointestinal tumors with activation of KRAS.

The Association Between AURKA Gene rs2273535 Polymorphism and Gastric Cancer Risk in a Chinese Population.

The Aurora kinase A (AURKA) gene is frequently amplified and overexpressed in gastric cancer (GC). The overexpression of AURKA promotes inflammation and tumorigenesis in GC. We performed co-expression analysis to identify genes associated with AURKA and speculated its function through the COXPRESdb and STRING databases. We also conducted a hospital-based case-control study involving 385 GC cases and 470 controls in a Chinese population to evaluate the role of AURKA gene rs2273535 polymorphism in the risk of GC. Genotyping was performed using a custom-by-design 48-Plex single nucleotide polymorphism (SNP) Scan™ Kit. Co-expression analysis indicated that the overexpression of AURKA may be associated with poor prognosis of GC. In addition, TT genotypes of rs2273535 polymorphism increased the risk of GC by 72% compared to the AA genotypes. This significant correlation was also observed in the allelic and dominant models. The stratified analysis suggested that TT+AT genotypes showed positive correlation with the risk of GC among female, age <55 years group and non-smokers compared to AA genotypes. In conclusion, AURKA plays an important role in the development of GC. Larger studies with more diverse ethnic populations are needed to confirm these results.

ARD1-mediated aurora kinase A acetylation promotes cell proliferation and migration.

Aurora kinase A (AuA) is a prerequisite for centrosome maturation, separation, and mitotic spindle assembly, thus, it is essential for cell cycle regulation. Overexpression of AuA is implicated in poor prognosis of many types of cancer. However, the regulatory mechanisms underlying the functions of AuA are still not fully understood. Here, we report that AuA colocalizes with arrest defective protein 1 (ARD1) acetyltransferase during cell division and cell migration. Additionally, AuA is acetylated by ARD1 at lysine residues at positions 75 and 125. The double mutations at K75/K125 abolished the kinase activity of AuA. Moreover, the double mutant AuA exhibited diminished ability to promote cell proliferation and cell migration. Mechanistic studies revealed that AuA acetylation at K75/K125 promoted cell proliferation via activation of cyclin E/CDK2 and cyclin B1. In addition, AuA acetylation stimulated cell migration by activating the p38/AKT/MMP-2 pathway. Our findings indicate that ARD1-mediated acetylation of AuA enhances cell proliferation and migration, and probably contributes to cancer development.

Activation of EIF4E by Aurora Kinase A Depicts a Novel Druggable Axis in Everolimus-Resistant Cancer Cells.

Purpose: Aurora kinase A (AURKA) is overexpressed in several cancer types, making it an attractive druggable target in clinical trials. In this study, we investigated the role of AURKA in regulating EIF4E, cap-dependent translation, and resistance to mTOR inhibitor, RAD001 (everolimus).Experimental Design: Tumor xenografts and in vitro cell models of upper gastrointestinal adenocarcinomas (UGC) were used to determine the role of AURKA in the activation of EIF4E and cap-dependent translation. Overexpression, knockdown, and pharmacologic inhibition of AURKA were used in vitro and in vivoResults: Using in vitro cell models, we found that high protein levels of AURKA mediate phosphorylation of EIF4E and upregulation of c-MYC. Notably, we detected overexpression of endogenous AURKA in everolimus-resistant UGC cell models. AURKA mediated phosphorylation of EIF4E, activation of cap-dependent translation, and an increase in c-MYC protein levels. Targeting AURKA using genetic knockdown or a small-molecule inhibitor, alisertib, reversed these molecular events, leading to a decrease in cancer cell survival in acquired and intrinsic resistant cell models. Mechanistic studies demonstrated that AURKA binds to and inactivates protein phosphatase 2A, a negative regulator of EIF4E, leading to phosphorylation and activation of EIF4E in an AKT-, ERK1/2-, and mTOR-independent manner. Data from tumor xenograft mouse models confirmed that everolimus-resistant cancer cells are sensitive to alisertib.Conclusions: Our results indicate that AURKA plays an important role in the activation of EIF4E and cap-dependent translation. Targeting the AURKA-EIF4E-c-MYC axis using alisertib is a novel therapeutic strategy that can be applicable for everolimus-resistant tumors and/or subgroups of cancers that show overexpression of AURKA and activation of EIF4E and c-MYC. Clin Cancer Res; 23(14); 3756-68. ©2017 AACR.

Abstract 1876: Cell cycle-dependent front polarized cell migration requires Aurora kinase A

Abstract PROBLEM- Metastasis accounts for 90% of deaths from carcinomas. BACKGROUND- To initiate migration, epithelial cells must front-rear polarize and reorganize the microtubule cytoskeleton directed toward the lamillipodia or leading edge. During mitosis, centrosome maturation, duplication, spindle pole assembly and chromosome segregation require Aurora kinase A (AURKA), which is optimally active when complexed with TPX2. Accumulating evidences identify non-mitotic functions for AURKA, such as cell migration and ciliary reorganization. Overexpression of AURKA leads to tumorigenesis in breast cancer. Mechanisms that activate non-mitotic AURKA and promote cell migration as well as metastasis are yet to be uncovered. RESULTS- In a large breast cancer tissue microarray (n= 3,175), the abundance of phosphorylated RHAMM (a substrate of AURKA) predicted overall and relapse-free survival in ER-negative, basal-subtype, and triple negative breast tumors. We studied the AURKA-TPX2-RHAMM signaling axis in mammary (MCF10A and nMUMG-FUCCI) and HeLa cells. In scratch wound assays, migratory cells were found to have front-polarized centrosomes, which correlated with G2 cell cycle phase, phosphorylated AURKA and elevated microtubule nucleation at centrosomes. Small molecule inhibition of Aurora kinase activity impaired centrosome polarity and retarded the kinetics of cell migration. In parallel, silencing RHAMM altered TPX2 location as indicated by immunofluorescence and immuno-EM, which located TPX2 to the nuclear envelope and nuclear pore basket. Nuclear import of recombinant TPX2 was attenuated in RHAMM silenced cells and nuclear envelope accumulation was elevated. CONCLUSION- The AURKA-TPX2-RHAMM axis regulates centrosome polarity, microtubule nucleation and directional cell migration while phosphorylated RHAMM predicts survival in aggressive forms of breast cancer. Citation Format: Tony Lok Heng Chu, Lixin Zhou, Jennifer Won, Pooja Mohan, Oksana Nemirovsky, Abbas Fotovati, Torsten Nielsen, Nelly Pante, Christopher Maxwell. Cell cycle-dependent front polarized cell migration requires Aurora kinase A [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1876. doi:10.1158/1538-7445.AM2017-1876

Cisplatin-resistant cancer cells are sensitive to Aurora kinase A inhibition by alisertib.

De novo and acquired resistance to platinum therapy such as cisplatin (CDDP) is a clinical challenge in gastric cancer treatment. Aberrant expression and activation of aurora kinase A (AURKA) and eukaryotic translation initiation factor 4E (eIF4E) are detected in several cancer types. Herein, we investigated the role of AURKA in CDDP resistance in gastric cancer. Western blot analysis demonstrated overexpression of AURKA and phosphorylation of eIF4E in acquired and de novo CDDP‐resistant gastric cancer models. Inhibition of AURKA with MLN8237 (alisertib) alone or in combination with CDDP significantly suppressed viability of CDDP‐resistant cancer cells (P < 0.01). Additionally, inhibition or knockdown of AURKA decreased protein expression of p‐eIF4E (S209), HDM2, and c‐MYC in CDDP‐resistant cell models. This was associated with a significant decrease in cap‐dependent translation levels (P < 0.01). In vivo tumor xenografts data corroborated these results and confirmed that inhibition of AURKA was sufficient to overcome CDDP resistance in gastric cancer. Our data demonstrate that AURKA promotes acquired and de novo resistance to CDDP through regulation of p‐eIF4E (S209), c‐MYC, HDM2, and cap‐dependent translation. Targeting AURKA could be an effective therapeutic approach to overcome CDDP resistance in refractory gastric cancer and possibly other cancer types.

Phase I study combining the aurora kinase A (AURKA) inhibitor alisertib (Ali) with mFOLFOX in gastrointestinal (GI) cancer.

2593 Background: Overexpression and cellular mis-localization of AURKA in GI cancers results in chromosomal instability, activation of several oncogenic pathways, and inhibition of pro-apoptotic signaling. Inhibition of AURKA causes mitotic delays, severe chromosome congression, and activation of p53/p73 causing cell death. Our preclinical data showed synergy of Ali and platinum agents in GI cells and xenografts, and suggested an optimal timing window of the combination. The purpose of this study was to assess safety of Ali + mFOLFOX, as this is a standard platinum-based therapy for GI cancers. Methods: This CTEP-sponsored, investigator-initiated, study (NCT02319018) used standard 3+3 dose escalation to determine the maximum tolerated dose (MTD) of Ali + mFOLFOX. Eligible patients (pts) had metastatic or unresectable GI cancer where standard therapies did not exist or were no longer effective, or for whom FOLFOX was appropriate. Pts received escalating doses of Ali starting at 10 mg twice daily (D1-3), with leucovorin + oxaliplatin (85 mg/m2) on D2 followed by continuous 5FU (2400 mg/m2) infusion on D2-4 in 14-day cycles. Dose-limiting toxicity (DLT) was any treatment-related non-hematologic ≥Gr3 toxicity (except diarrhea or nausea, vomiting, controllable with meds) or ≥Gr4 hematologic toxicity observed during the first 28 days. Results: 13 pts were enrolled and 2 dose levels explored; 2 pts were not evaluable for DLT and replaced. Zero DLTs observed in first 3 pts. Ali was escalated to 20 mg where 2/6 had a DLT [Gr3 fatigue (n = 2); Gr3 nausea, vomiting, dehydration with hospitalization (n = 1)]. Ali was de-escalated and 2 of 3 pts have been enrolled; 0 DLTs observed thus far. Most frequent toxicities (%) were nausea (54), fatigue (46), neuropathy (46), anorexia (38), and anemia (38), most ≤Gr2. One of 10 evaluable pts had a partial response, and 6 had stable disease for a 70% disease control rate. Conclusions: The MTD will be 10 mg Ali (D1-3) + oxaliplatin (D2, 85 mg/m2) + continuous 5FU (D2-4, 2400 mg/m2). The combination was tolerable, and preliminary clinical activity was seen in a majority of pts. Correlative biomarker studies to evaluate AURKA target inhibition are ongoing and will be reported. Clinical trial information: NCT02319018.

AURKA promotes cancer metastasis by regulating epithelial-mesenchymal transition and cancer stem cell properties in hepatocellular carcinoma

AURKA (aurora kinase A) has been confirmed as an oncogene in cancer development; however, its role and underlying mechanisms in the metastasis of hepatocellular carcinoma (HCC) remain unknown. In this study, We found that AURKA was up-regulated in HCC tissues and correlated with pathological stage and distant metastasis. Further found that AURKA was involved in the cancer metastases after radiation in HCC. While overexpression of AURKA induced epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) behaviors though PI3K/AKT pathway, silencing AURKA suppressed radiation-enhanced cell invasiveness of HCC. Taken together, our results suggested that AURKA contributed in metastasis of irradiated residul HCC though facilitating EMT and CSC properties, suggesting the potential clinical application of AURKA inhibitors in radiotherapy for patients with HCC.

Activation of the FAK/PI3K pathway is crucial for AURKA-induced epithelial-mesenchymal transition in laryngeal cancer.

Laryngeal squamous cell carcinoma (LSCC) is one of the most common malignant tumors, and the main cause of death is metastasis. Overexpression of aurora kinaseA (AURKA) plays an important role in the metastasis of LSCC. However, the mechanism by which AURKA promotes the metastasis of LSCC is poorly understood. Recent accumulating evidence indicates that epithelial-mesenchymal transition (EMT) may be one of the mechanisms of tumor metastasis. In the present study, we studied whether AURKA may induce EMT to promote the metastasis of LSCC. CCK-8 and plate colony-formation assays were carried out to show that AURKA significantly promoted the proliferation of Hep2 cells. Immunofluorescence staining and western blotting showed that EMT-related proteins changed in a time-dependent manner along with the alteration of AURKA, with decreased expression of N-cadherin, vimentin and slug and increased expression of E-cadherin. Additionally, downregulation of the expression of AURKA inhibited FAK/PI3K pathway activity. Inhibition of the FAK/PI3K pathway caused less mesenchymal-like characteristics and reduced the mobility, migration and invasion of Hep2 cells. In conclusion, AURKA may induce EMT to promote metastasis via activation of the FAK/PI3K pathway in LSCC. Those regulatory factors may present new diagnostic biomarkers and potential therapeutic targets for LSCC.

Aurora Kinase A is critical for the Nkx6.1 mediated β‐cell proliferation pathway

Type 1 and type 2 diabetes are ultimately characterized by depleted β‐cell mass. Characterization of the molecular pathways that control β‐cell proliferation could be harnessed to restore these cells. The homeobox β‐cell transcription factor Nkx6.1 induces β‐cell proliferation by activating the orphan nuclear receptors Nr4a1 and Nr4a3. Here, we demonstrate that Nkx6.1 localizes to the promoter of the mitotic kinase AURKA (Aurora Kinase A) and induces its expression. Adenovirus mediated overexpression of AURKA is sufficient to induce proliferation in primary rat islets while maintaining glucose stimulated insulin secretion. Furthermore, AURKA is necessary for Nkx6.1 mediated β‐cell proliferation as demonstrated by shRNA mediated knock down and pharmacological inhibition of AURKA kinase activity. AURKA preferentially induces DNA replication in β‐cells as measured by BrdU incorporation, and enhances the rate of histone H3 phosphorylation in primary β‐cells, demonstrating that AURKA induces the replicative and mitotic cell cycle phases in rat β‐cells. Finally, overexpression of AURKA results in phosphorylation of the cell cycle regulator p53, which targets p53 for degradation and permits cell cycle progression. These studies define a pathway by which AURKA upregulation by Nkx6.1 results in phosphorylation and degradation of p53, thus removing a key inhibitory factor and permitting engagement of the β‐cell proliferation pathway.