Aurora kinase-A inactivates DNA damage-induced apoptosis and spindle assembly checkpoint response functions of p73

SOX9 is regulated by AURKA in response to Helicobacter pylori infection via EIF4E-mediated cap-dependent translation

Helicobacter pylori (H. pylori) infection is the main risk factor for gastric cancer. The SRY-Box Transcription Factor 9 (SOX9) serves as a marker of stomach stem cells. We detected strong associations between AURKA and SOX9 expression levels in gastric cancers. Utilizing in vitro and in vivo mouse models, we demonstrated that H. pylori infection induced elevated levels of both AURKA and SOX9 proteins. Notably, the SOX9 protein and transcription activity levels were dependent on AURKA expression. AURKA knockdown led to a reduction in the number and size of gastric gland organoids. Conditional knockout of AURKA in mice resulted in a decrease in SOX9 baseline level in AURKA-knockout gastric glands, accompanied by diminished SOX9 induction following H. pylori infection. We found an AURKA-dependent increase in EIF4E and cap-dependent translation with an AURKA-EIF4E-dependent increase in SOX9 polysomal RNA levels. Immunoprecipitation assays demonstrated binding of AURKA to EIF4E with a decrease in EIF4E ubiquitination. Immunohistochemistry analysis on tissue arrays revealed moderate to strong immunostaining of AURKA and SOX9 with a significant correlation in gastric cancer tissues. These findings elucidate the mechanistic role of AURKA in regulating SOX9 levels via cap-dependent translation in response to H. pylori infection in gastric tumorigenesis.

eEF1A2 promotes PTEN-GSK3β-SCF complex-dependent degradation of Aurora kinase A and is inactivated in breast cancer

The translation elongation factor eEF1A promotes protein synthesis. Its methylation by METTL13 increases its activity, supporting tumor growth. However, in some cancers, a high abundance of eEF1A isoforms is associated with a good prognosis. Here, we found that eEF1A2 exhibited oncogenic or tumor-suppressor functions depending on its interaction with METTL13 or the phosphatase PTEN, respectively. METTL13 and PTEN competed for interaction with eEF1A2 in the same structural domain. PTEN-bound eEF1A2 promoted the ubiquitination and degradation of the mitosis-promoting Aurora kinase A in the S and G2 phases of the cell cycle. eEF1A2 bridged the interactions between the SKP1-CUL1-FBXW7 (SCF) ubiquitin ligase complex, the kinase GSK3β, and Aurora-A, thereby facilitating the phosphorylation of Aurora-A in a degron site that was recognized by FBXW7. Genetic ablation of Eef1a2 or Pten in mice resulted in a greater abundance of Aurora-A and increased cell cycling in mammary tumors, which was corroborated in breast cancer tissues from patients. Reactivating this pathway using fimepinostat, which relieves inhibitory signaling directed at PTEN and increases FBXW7 expression, combined with inhibiting Aurora-A with alisertib, suppressed breast cancer cell proliferation in culture and tumor growth in vivo. The findings demonstrate a therapeutically exploitable, tumor-suppressive role for eEF1A2 in breast cancer.

Platinum-based targeted chemotherapies and reversal of cisplatin resistance in non-small cell lung cancer (NSCLC)

Lung cancer is the one of the most prevalent cancer in the world. It kills more people from cancer than any other cause and is especially common in underdeveloped nations. With 1.2 million instances, it is also the most prevalent cancer in men worldwide, making about 16.7% of the total cancer burden. Surgery is the main form of curative treatment for early-stage lung cancer. However, the majority of patients had incurable advanced non-small cell lung cancer (NSCLC) recurrence after curative purpose surgery, which is indicative of the aggressiveness of the illness and the dismal outlook. The gold standard of treatment for NSCLC patients includes drug targeting of specific mutated genes drive in development of lung cancer. Furthermore, patients with advanced NSCLC and those with early-stage illness needing adjuvant therapy should use cisplatin as it is the more active platinum drug. So, this review encompasses the non-small cell lung cancer microenvironment, treatment approaches, and use of cisplatin as a first-line regimen for NSCLC, its mechanism of action, cisplatin resistance in NSCLC and also the prevention strategies to revert the drug resistance.

A new wave of innovations within the DNA damage response

Genome instability has been identified as one of the enabling hallmarks in cancer. DNA damage response (DDR) network is responsible for maintenance of genome integrity in cells. As cancer cells frequently carry DDR gene deficiencies or suffer from replicative stress, targeting DDR processes could induce excessive DNA damages (or unrepaired DNA) that eventually lead to cell death. Poly (ADP-ribose) polymerase (PARP) inhibitors have brought impressive benefit to patients with breast cancer gene (BRCA) mutation or homologous recombination deficiency (HRD), which proves the concept of synthetic lethality in cancer treatment. Moreover, the other two scenarios of DDR inhibitor application, replication stress and combination with chemo- or radio- therapy, are under active clinical exploration. In this review, we revisited the progress of DDR targeting therapy beyond the launched first-generation PARP inhibitors. Next generation PARP1 selective inhibitors, which could maintain the efficacy while mitigating side effects, may diversify the application scenarios of PARP inhibitor in clinic. Albeit with unavoidable on-mechanism toxicities, several small molecules targeting DNA damage checkpoints (gatekeepers) have shown great promise in preliminary clinical results, which may warrant further evaluations. In addition, inhibitors for other DNA repair pathways (caretakers) are also under active preclinical or clinical development. With these progresses and efforts, we envision that a new wave of innovations within DDR has come of age.

Isolation and anticancer activity of quercetin from Acalypha indica L. against breast cancer cell lines MCF-7 and MDA-MB-231

In this study, the active components of the plant were carefully extracted and identified using three solvent systems. After extraction, we used solvent systems to further purify the main flavonoid chemical constituent. As a result of our analytical strategy, which included HPLC analysis, MS/MS spectroscopic analysis, and NMR data-based constructions, quercetin was determined to be the main chemical constituent. Our study suggests the potential therapeutic advantages of quercetin, a compound found in the leaves of Acalypha indica, for treating breast cancer cell lines MCF-7 and MDA-MB-231. Our comparison of Quercetin to the regularly prescribed medicine Doxorubicin shows that it has the capacity to inhibit MCF-7 and MDA-MB-231 cells. Measurements of apoptosis and cell cycle phase showed this to be the case. Furthermore, a ladder that formed as a result of cellular damage brought on by ROS provided further proof of the drug's impact on DNA integrity. Notably, pro-apoptotic proteins displayed increased apoptosis activity in cells treated with quercetin. Given that it is extracted from plants and has less adverse effects than other compounds, quercetin is a viable option for further clinical study. The objective is to fight breast cancer, one of the most prevalent diseases in the world and a main cause of death for women. Thus, our research makes a significant addition to the ongoing search for potent, plant-based breast cancer treatments.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03705-w.

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.

The CNS-penetrating taxane drug TPI 287 potentiates antiglioma activity of the AURKA inhibitor alisertib in vivo

INTRODUCTION

Glioblastoma (GBM) has a very poor prognosis despite current treatment. We previously found cytotoxic synergy between the AURKA inhibitor alisertib and the CNS-penetrating taxane TPI 287 against GBM tumor cells in vitro.

METHODS

We used an orthotopic human GBM xenograft mouse model to test if TPI 287 potentiates alisertib in vivo. Western blotting, immunohistochemistry, siRNA knockdown, annexin V binding, and 3-dimensional Matrigel invasion assays were used to investigate potential mechanisms of alisertib and TPI 287 treatment interactions.

RESULTS

Alisertib + TPI 287 combination therapy significantly prolonged animal survival compared to vehicle (p = 0.011), but only marginally compared to alisertib alone. Alisertib, TPI 287, and combined alisertib + TPI 287 reduced animal tumor volume compared to vehicle-treated controls. This was statistically significant for the combination therapy at 4 weeks (p < 0.0001). Alisertib + TPI 287 treatment decreased anti-apoptotic Bcl-2 protein levels in vivo and in vitro. Expression of the pro-apoptotic protein Bak was significantly increased by combination treatment (p < 0.0001). Pro-apoptotic Bim and Bak knockdown by siRNA decreased apoptosis by alisertib + TPI 287 in GB9, GB30, and U87 cells (p = 0.0005 to 0.0381). Although alisertib and TPI 287 significantly reduced GBM cell invasion (p < 0.0001), their combination was no more effective than TPI 287 alone.

CONCLUSIONS

Results suggest that apoptosis is the dominant mechanism of potentiation of GBM growth inhibition by alisertib + TPI 287, in part through effects on Bcl-2 family proteins, providing a rationale for further laboratory testing of an AURKA inhibitor plus TPI 287 as a potential therapy against GBM.

Deciphering the Role of p53 and TAp73 in Neuroblastoma: From Pathogenesis to Treatment

Neuroblastoma (NB) is an embryonic cancer that develops from neural crest stem cells, being one of the most common malignancies in children. The clinical manifestation of this disease is highly variable, ranging from spontaneous regression to increased aggressiveness, which makes it a major therapeutic challenge in pediatric oncology. The p53 family proteins p53 and TAp73 play a key role in protecting cells against genomic instability and malignant transformation. However, in NB, their activities are commonly inhibited by interacting proteins such as murine double minute (MDM)2 and MDMX, mutant p53, ΔNp73, Itch, and Aurora kinase A. The interplay between the p53/TAp73 pathway and N-MYC, a known biomarker of poor prognosis and drug resistance in NB, also proves to be decisive in the pathogenesis of this tumor. More recently, a strong crosstalk between microRNAs (miRNAs) and p53/TAp73 has been established, which has been the focused of great attention because of its potential for developing new therapeutic strategies. Collectively, this review provides an updated overview about the critical role of the p53/TAp73 pathway in the pathogenesis of NB, highlighting encouraging clues for the advance of alternative NB targeted therapies.

The Anaphase-Promoting Complex/Cyclosome Is a Cellular Ageing Regulator

The anaphase-promoting complex/cyclosome (APC/C) is a complicated cellular component that plays significant roles in regulating the cell cycle process of eukaryotic organisms. The spatiotemporal regulation mechanisms of APC/C in distinct cell cycle transitions are no longer mysterious, and the components of this protein complex are gradually identified and characterized. Given the close relationship between the cell cycle and lifespan, it is urgent to understand the roles of APC/C in lifespan regulation, but this field still seems to have not been systematically summarized. Furthermore, although several reviews have reported the roles of APC/C in cancer, there are still gaps in the summary of its roles in other age-related diseases. In this review, we propose that the APC/C is a novel cellular ageing regulator based on its indispensable role in the regulation of lifespan and its involvement in age-associated diseases. This work provides an extensive review of aspects related to the underlying mechanisms of APC/C in lifespan regulation and how it participates in age-associated diseases. More comprehensive recognition and understanding of the relationship between APC/C and ageing and age-related diseases will increase the development of targeted strategies for human health.

Construction and validation of gastric cancer diagnosis model based on machine learning

Aim: To screen differentially expressed genes related to gastric cancer based on The Cancer Genome Atlas (TCGA) database and construct a gastric cancer diagnosis model by machine learning. Methods: Transcriptional data, genomic data, and clinical information of gastric cancer tissues and non-gastric cancer tissues were downloaded from the TCGA database, and differentially expressed genes of gastric cancer messenger RNA (mRNA) and long non-coding RNA (lncRNA) were screened out. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyzed the differentially expressed genes, and the protein-protein interaction (PPI) of differentially expressed genes was constructed. Core differentially expressed genes were screened by Cytoscape software’s molecular complex detection (MCODE) plug-in. The differential genes of lncRNA were analyzed by univariate Cox regression analysis and lasso regression for further dimension reduction to obtain the core genes. The core genes were screened by machine learning to construct the gastric cancer diagnosis model. The efficiency of the gastric cancer diagnosis model was verified externally by the Gene Expression Omnibus (GEO) database. Results: Finally, 10 genes including long intergenic non-protein coding RNA 1821 (LINC01821), AL138826.1, AC022164.1, adhesion G protein-coupled receptor D1-antisense RNA 1 (ADGRD1-AS1), cyclin B1 (CCNB1), kinesin family member 11 (KIF11), Aurora kinase B (AURKB), cyclin dependent kinase 1 (CDK1), nucleolar and spindle associated protein 1 (NUSAP1), and TTK protein kinase (TTK) were screened as gastric cancer diagnostic model genes. After efficiency analysis, it was found that the random forest algorithm model had the best comprehensive evaluation, with an accuracy of 92% and an area under the curve (AUC) of 0.9722, which was more suitable for building a gastric cancer diagnosis model. The GSE54129 data set was used to verify the gastric cancer diagnosis model with an AUC of 0.904, indicating that the gastric cancer diagnosis model had high accuracy. Conclusions: Machine learning can simplify the bioinformatics analysis process and improve efficiency. The core gene discovered in this study is expected to become a gene chip for the diagnosis of gastric cancer.

Aurora kinase a inhibitor MLN8237 suppresses pancreatic cancer growth

Pancreatic ductal adenocarcinoma (PDAC) is notorious for high mortality due to limited options of appropriate chemotherapy drugs. Here we report that Aurora kinase-A expression is elevated in both human and mouse PDAC samples. MLN8237, an inhibitor of Aurora kinase-A, efficiently reduced the proliferation and motility of PDAC cells in vitro as well as tumor growth in orthotropic xenograft model and genetic pancreatic cancer animal models (p53/LSL/Pdx-Cre mice) in vivo. MLN8237 exhibited tumor inhibitory effect through inhibiting proliferation and migration, and inducing apoptosis and senescence. These results provide the molecular basis for a novel chemotherapy strategy for PDAC patients.

Posttranslational modification of Aurora A-NSD2 loop contributes to drug resistance in t(4;14) multiple myeloma

Background

t(4;14)(p16;q32) cytogenetic abnormality renders high level of histone methyltransferase NSD2 in multiple myeloma (MM) patients, and predicts poor clinical prognosis, but mechanisms of NSD2 in promoting chemoresistance have not been well elucidated.

Methods

An epigenetics compound library containing 181 compounds was used to screen inhibitors possessing a prior synergistic effect with bortezomib (BTZ) in vitro. Molecular biology techniques were applied to uncover underlying mechanisms. Transcriptome profile assay was performed by RNA‐seq. NSG mouse‐based xenograft model and intra‐bone model were applied to qualify the synergistic effect in vivo.

Results

We identified an Aurora kinase A inhibitor (MLN8237) possessed a significant synergistic effect with BTZ on t(4;14) positive MM cells. Aurora A protein level positively correlated with NSD2 level, and gain‐ and loss‐of‐functions of Aurora A correspondingly altered NSD2 protein and H3K36me2 levels. Mechanistically, Aurora A phosphorylated NSD2 at S56 residue to protect the protein from cleavage and degradation, thus methylation of Aurora A and phosphorylation of NSD2 bilaterally formed a positive regulating loop. Transcriptome profile assay of MM cells with AURKA depletion identified IL6R, STC2 and TCEA2 as the downstream target genes responsible for BTZ‐resistance (BR). Clinically, higher expressions of these genes correlated with poorer outcomes of MM patients. Combined administration of MLN8237 and BTZ significantly suppressed tumour growth in LP‐1 cells derived xenografts, and remarkably alleviated bone lesion in femurs of NSG mice.

Conclusions

Aurora A phosphorylates NSD2 at S56 residue to enhance NSD2 methyltransferase activity and form a positive regulating loop in promoting MM chemoresistance, thus pharmacologically targeting Aurora A sensitizes t(4;14) positive MM to the proteasome inhibitors treatment. Our study uncovers a previously unknown reason of MM patients with t(4;14) engendering chemoresistance, and provides a theoretical basis for developing new treatment strategy for MM patients with different genomic backgrounds.

Clinical outcomes associated with expression of aurora kinase and p53 family members in muscle‑invasive bladder cancer

Biomarkers are needed in muscle-invasive bladder cancer (MIBC). We previously reported that high tumor aurora kinase (AURK) A expression identifies patients with MIBC with poor prognosis. Aberrant p53 expression has also been associated with poor outcomes in MIBC, though to the best of our knowledge, co-expression rates of p53 and aurora kinases have not been previously described in MIBC. As aurora kinase and p53 family members may co-regulate each other, the present study investigated whether tumor p53 or p63 protein expression influenced the prognostic value of AURKA in a pilot study of 50 patients with MIBC treated with curative intent. Immunohistochemistry for AURKA, AURKB, p53 and p63 were performed on archival pre-treatment tumor specimens and correlated with clinical outcomes in patients with MIBC who received neoadjuvant chemotherapy (NAC) prior to cystectomy. Baseline p53 [hazard ratio (HR) 1.46; 95% confidence interval (CI)=0.55-3.9; P=0.448) and p63 (HR 2.02; 95% CI=0.51-8.1; P=0.313) protein expression did not predict for overall survival (OS). Low p53 protein expression did not correlate with high AURKA (φ=0.190) or AURKB (φ=0.075) expression. However, in tumors with low p53 expression (n=17), the presence of either high AURKA or AURKB expression levels predicted an increased risk for relapse (HR 27.1; 95% CI=2.7-270.1; P=0.005) and mortality (HR 14.9; 95% CI=2.3-95.6; P=0.004) compared to tumors with both low AURKA and AURKB levels. The relationship between p63 and AURKA/B expression levels was not tested due to the prevalence (80%) of high p63 expression in the present cohort. In tumors with low AURKA expression, p53 status did not predict for OS (HR 0.62; 95% CI 0.2-3.2; P=0.572). In multivariable analysis, only high baseline AURKA expression predicted for inferior OS (HR 4.9; 95% CI 1.7-14.1; P=0.003). To the best of our knowledge, the present study was the first to report co-expression of p53 and aurora kinase family members in MIBC, and although wild-type p53 may regulate the aurora kinases in preclinical models, the adverse prognostic value of tumor AURKA overexpression was independent from baseline tumor p53 protein expression in the present cohort. AURKA remains an important prognostic biomarker in patients with MIBC and warrants further evaluation in prospective studies to validate whether baseline AURKA can identify patients that are unlikely to benefit from standard of care with NAC.

The p53 family member p73 in the regulation of cell stress response

During oncogenesis, cells become unrestrictedly proliferative thereby altering the tissue homeostasis and resulting in subsequent hyperplasia. This process is paralleled by resumption of cell cycle, aberrant DNA repair and blunting the apoptotic program in response to DNA damage. In most human cancers these processes are associated with malfunctioning of tumor suppressor p53. Intriguingly, in some cases two other members of the p53 family of proteins, transcription factors p63 and p73, can compensate for loss of p53. Although both p63 and p73 can bind the same DNA sequences as p53 and their transcriptionally active isoforms are able to regulate the expression of p53-dependent genes, the strongest overlap with p53 functions was detected for p73. Surprisingly, unlike p53, the p73 is rarely lost or mutated in cancers. On the contrary, its inactive isoforms are often overexpressed in cancer. In this review, we discuss several lines of evidence that cancer cells develop various mechanisms to repress p73-mediated cell death. Moreover, p73 isoforms may promote cancer growth by enhancing an anti-oxidative response, the Warburg effect and by repressing senescence. Thus, we speculate that the role of p73 in tumorigenesis can be ambivalent and hence, requires new therapeutic strategies that would specifically repress the oncogenic functions of p73, while keeping its tumor suppressive properties intact.

Aurora kinases in ovarian cancer

Aurora kinases (AURK) are key regulators of the mitotic spindle formation. AURK is frequently overexpressed in ovarian cancer and this overexpression has been frequently associated with prognosis in these tumours. Interestingly, AURK have been shown to interact with DNA repair mechanisms and other cell cycle regulators. These functions have brought light to Aurora family as a potential target for anticancer therapy. In the last years, two clinical trials with different AURK inhibitors have shown activity in epithelial and clear-cell ovarian cancer. Although there is a lack of predictive factors of AURK inhibition activity, recent trials have identified some candidates. This review will focus in the functions of the AURK family, its role as prognostic factor in epithelial ovarian cancer and potential clinical implications.

Integrated pan-cancer of AURKA expression and drug sensitivity analysis reveals increased expression of AURKA is responsible for drug resistance

Introduction

The AURKA gene encodes a protein kinase involved in cell cycle regulation and plays an oncogenic role in many cancers. The main objective of this study is to analyze AURKA expression in 13 common cancers and its role in prognostic and drug resistance.

Method

Using the cancer genome atlas (TCGA) as well as CCLE and GDSC data, the level of AURKA gene expression and its role in prognosis and its association with drug resistance were evaluated, respectively. In addition, the expression level of AURKA was assessed in colorectal cancer (CRC) and gastric cancer (GC) samples. Besides, using Gene Expression Omnibus (GEO) data, drugs that could affect the expression level of this gene were also identified.

Results

The results indicated that the expression level of AURKA gene in 13 common cancers increased significantly compared to normal samples or it survived poorly (HR >1, p < 0.01) in lung, prostate, kidney, bladder, and uterine cancers. Also, the gene expression data showed increased expression in CRC and GC samples compared to normal ones. The level of AURKA was significantly associated with the resistance to SB 505124, NU‐7441, and irinotecan drugs (p < 0.01). Eventually, GEO data showed that JQ1, actinomycin D1, and camptothecin could reduce the expression of AURKA gene in different cancer cell lines (logFC < 1, p < 0.01).

Conclusion

Increased expression of AURKA is observed in prevalent cancers and associated with poor prognostic and the development of drug resistance. In addition, some chemotherapy drugs can reduce the expression of this gene.

Intra-heterogeneity in transcription and chemoresistant property of leukemia-initiating cells in murine Setd2-/- acute myeloid leukemia

BACKGROUND

Heterogeneity of leukemia-initiating cells (LICs) is a major obstacle in acute myeloid leukemia (AML) therapy. Accumulated evidence indicates that the coexistence of multiple types of LICs with different pathogenicity in the same individual is a common feature in AML. However, the functional heterogeneity including the drug response of coexistent LICs remains unclear. Therefore, this study aimed to clarify the intra-heterogeneity in LICs that can help predict leukemia behavior and develop more effective treatments.

METHODS

Spleen cells from the primary Setd2^-/- -AML mouse were transplanted into C57BL/6 recipient mice to generate a transplantable model. Flow cytometry was used to analyze the immunophenotype of the leukemic mice. Whole-genome sequencing was conducted to detect secondary hits responsible for leukemia transformation. A serial transplantation assay was used to determine the self-renewal potential of Setd2^-/- -AML cells. A limiting-dilution assay was performed to identify the LIC frequency in different subsets of leukemia cells. Bulk and single-cell RNA sequencing were performed to analyze the transcriptional heterogeneity of LICs. Small molecular inhibitor screening and in vivo drug treatment were employed to clarify the difference in drug response between the different subsets of LICs.

RESULTS

In this study, we observed an aged Setd2^-/- mouse developing AML with co-mutation of Nras^G12S and Braf^K520E . Further investigation identified two types of LICs residing in the c-Kit⁺ B220⁺ Mac-1^- and c-Kit⁺ B220⁺ Mac-1⁺ subsets, respectively. In vivo transplantation assay disclosed the heterogeneity in differentiation between the coexistent LICs. Besides, an intrinsic doxorubicin-resistant transcriptional signature was uncovered in c-Kit⁺ B220⁺ Mac-1⁺ cells. Indeed, doxorubicin plus cytarabine (DA), the standard chemotherapeutic regimen used in AML treatment, could specifically kill c-Kit⁺ B220⁺ Mac-1^- cells, but it hardly affected c-Kit⁺ B220⁺ Mac-1⁺ cells. Transcriptome analysis unveiled a higher activation of RAS downstream signaling pathways in c-Kit⁺ B220⁺ Mac-1⁺ cells than in c-Kit⁺ B220⁺ Mac-1^- cells. Combined treatment with DA and RAS pathway inhibitors killed both c-Kit⁺ B220⁺ Mac-1^- and c-Kit⁺ B220⁺ Mac-1⁺ cells and attenuated disease progression.

CONCLUSIONS

This study identified two cell subsets enriched for LICs in murine Setd2^-/- -AML and disclosed the transcriptional and functional heterogeneity of LICs, revealing that the coexistence of different types of LICs in this model brings about diverse drug response.

Potential Molecular Targets in the Setting of Chemoradiation for Esophageal Malignancies

Although the development of effective combined chemoradiation regimens for esophageal cancers has resulted in statistically significant survival benefits, the majority of patients treated with curative intent develop locoregional and/or distant relapse. Further improvements in disease control and survival will require the development of individualized therapy based on the knowledge of host and tumor genomics and potentially harnessing the host immune system. Although there are a number of gene targets that are amplified and proteins that are overexpressed in esophageal cancers, attempts to target several of these have not proven successful in unselected patients. Herein, we review our current state of knowledge regarding the molecular pathways implicated in esophageal carcinoma, and the available agents for targeting these pathways that may rationally be combined with standard chemoradiation, with the hope that this commentary will guide future efforts of novel combinations of therapy.

Robust rank aggregation and cibersort algorithm applied to the identification of key genes in head and neck squamous cell cancer

OBJECTIVE

Although multiple hub genes have been identified in head and neck squamous cell cancer (HNSCC) in recent years, because of the limited sample size and inconsistent bioinformatics analysis methods, the results are not reliable. Therefore, it is urgent to use reliable algorithms to find new prognostic markers of HNSCC.

METHOD

The Robust Rank Aggregation (RRA) method was used to integrate 8 microarray datasets of HNSCC downloaded from the Gene Expression Omnibus (GEO) database to screen differentially expressed genes (DEGs). Later, Gene Ontology (GO) functional annotation together with Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis was carried out to discover functions of those discovered DEGs. According to the KEGG results, those discovered DEGs showed tight association with the occurrence and development of HNSCC. Then cibersort algorithm was used to analyze the infiltration of immune cells of HNSCC and we found that the main infiltrated immune cells were B cells, dendritic cells and macrophages. A protein-protein interaction (PPI) network was established; moreover, key modules were also constructed to select 5 hub genes from the whole network using cytoHubba. 3 hub genes showed significant relationship with prognosis for TCGA-derived HNSCC patients.

RESULT

The potent DEGs along with hub genes were selected by the combined bioinformatic approach. AURKA, BIRC5 and UBE2C genes may be the potential prognostic biomarker and therapeutic targets of HNSCC.

CONCLUSIONS

The Robust Rank Aggregation method and cibersort algorithm method can accurately predict the potential prognostic biomarker and therapeutic targets of HNSCC through multiple GEO datasets.

Dalhat M, Abdullah O, Kaleem M, Hosawi S, A Al-Abbasi F, Wu W, Choudhry H, Alhosin M. Targeting Post-Translational Modifications of the p73 Protein: A Promising Therapeutic Strategy for Tumors

The tumor suppressor p73 is a member of the p53 family and is expressed as different isoforms with opposing properties. The TAp73 isoforms act as tumor suppressors and have pro-apoptotic effects, whereas the ΔNp73 isoforms lack the N-terminus transactivation domain and behave as oncogenes. The TAp73 protein has a high degree of similarity with both p53 function and structure, and it induces the regulation of various genes involved in the cell cycle and apoptosis. Unlike those of the p53 gene, the mutations in the p73 gene are very rare in tumors. Cancer cells have developed several mechanisms to inhibit the activity and/or expression of p73, from the hypermethylation of its promoter to the modulation of the ratio between its pro- and anti-apoptotic isoforms. The p73 protein is also decorated by a panel of post-translational modifications, including phosphorylation, acetylation, ubiquitin proteasomal pathway modifications, and small ubiquitin-related modifier (SUMO)ylation, that regulate its transcriptional activity, subcellular localization, and stability. These modifications orchestrate the multiple anti-proliferative and pro-apoptotic functions of TAp73, thereby offering multiple promising candidates for targeted anti-cancer therapies. In this review, we summarize the current knowledge of the different pathways implicated in the regulation of TAp73 at the post-translational level. This review also highlights the growing importance of targeting the post-translational modifications of TAp73 as a promising antitumor strategy, regardless of p53 status.

Targeting AURKA in Cancer: molecular mechanisms and opportunities for Cancer therapy

Aurora kinase A (AURKA) belongs to the family of serine/threonine kinases, whose activation is necessary for cell division processes via regulation of mitosis. AURKA shows significantly higher expression in cancer tissues than in normal control tissues for multiple tumor types according to the TCGA database. Activation of AURKA has been demonstrated to play an important role in a wide range of cancers, and numerous AURKA substrates have been identified. AURKA-mediated phosphorylation can regulate the functions of AURKA substrates, some of which are mitosis regulators, tumor suppressors or oncogenes. In addition, enrichment of AURKA-interacting proteins with KEGG pathway and GO analysis have demonstrated that these proteins are involved in classic oncogenic pathways. All of this evidence favors the idea of AURKA as a target for cancer therapy, and some small molecules targeting AURKA have been discovered. These AURKA inhibitors (AKIs) have been tested in preclinical studies, and some of them have been subjected to clinical trials as monotherapies or in combination with classic chemotherapy or other targeted therapies.

Clinical and Biological Features of Neuroendocrine Prostate Cancer

PURPOSE OF REVIEW

Neuroendocrine prostate cancer (NEPC) is an aggressive histologic subtype of prostate cancer that most commonly arises in later stages of prostate cancer as a mechanism of treatment resistance. The poor prognosis of NEPC is attributed in part to late diagnosis and a lack of effective therapeutic agents. Here, we review the clinical and molecular features of NEPC based on recent studies and outline future strategies and directions.

RECENT FINDINGS

NEPC can arise "de novo" but most commonly develops as a result of lineage plasticity whereby prostate cancer cells adopt alternative lineage programs as a means to bypass therapy. Dependence on androgen receptor (AR) signaling is lost as tumors progress from a prostate adenocarcinoma to a NEPC histology, typically manifested by the downregulation of AR, PSA, and PSMA expression in tumors. Genomic analyses from patient biopsies combined with preclinical modeling have pointed to loss of tumor suppressors RB1 and TP53 as key facilitators of lineage plasticity. Activation of oncogenic drivers combined with significant epigenetic changes (e.g., EZH2 overexpression, DNA methylation) further drives tumor proliferation and expression of downstream neuronal and neuroendocrine lineage pathways controlled in part by pioneer and lineage determinant transcription factors (e.g., SOX2, ASCL1, BRN2). These biologic insights have provided a framework for the study of this subgroup of advanced prostate cancers and have started to provide rationale for the development of biomarker-driven therapeutic strategies. Further study of the dynamic process that leads to NEPC is required for the development of effective strategies to identify and treat patients developing lineage plasticity as a mechanism of treatment resistance.

Distinct p63 and p73 Protein Interactions Predict Specific Functions in mRNA Splicing and Polyploidy Control in Epithelia

Epithelial organs are the first barrier against microorganisms and genotoxic stress, in which the p53 family members p63 and p73 have both overlapping and distinct functions. Intriguingly, p73 displays a very specific localization to basal epithelial cells in human tissues, while p63 is expressed in both basal and differentiated cells. Here, we analyse systematically the literature describing p63 and p73 protein-protein interactions to reveal distinct functions underlying the aforementioned distribution. We have found that p73 and p63 cooperate in the genome stability surveillance in proliferating cells; p73 specific interactors contribute to the transcriptional repression, anaphase promoting complex and spindle assembly checkpoint, whereas p63 specific interactors play roles in the regulation of mRNA processing and splicing in both proliferating and differentiated cells. Our analysis reveals the diversification of the RNA and DNA specific functions within the p53 family.

Heat-killed Salmonella Typhimurium protects mice against carbon ion radiation

OBJECTIVE

Patients receiving carbon-ion radiation therapy and astronauts exploring outer space are inevitably exposed to heavy ion radiation. The aim of this study was to develop radioprotectors to minimize the injuries induced by carbon ion radiation.

METHODS

Heat-killed Salmonella Typhimurium (HKST) was administered to mice by gavage prior to irradiation with a ¹²C⁶⁺ heavy ion accelerator. Hematoxylin and eosin staining and immunofluorescence TdT-mediated dUTP Nick-End Labeling staining were used to assess the radioprotective effect of HKST on organ damage and levels of apoptosis, respectively, in mice. To investigate the mechanism underlying the radioprotective effect of HKST, levels of the pro-apoptotic proteins BAX and caspase 3 as well as interferon-regulatory factor (IRF) 3/7 in the femur, testis and intestine were assessed using immunofluorescence.

RESULTS

Injuries induced by carbon ion radiation were significantly eased by pretreatment with HKST. Both apoptosis and high expression levels of pro-apoptotic proteins induced by heavy ion radiation were inhibited by HKST pretreatment. The radioprotective effect of HKST was associated with stimulation of Toll-like receptor signaling mediated by enhanced IRF3 and IRF7 signaling.

CONCLUSION

HKST was an effective radioprotector alleviating damage to multiple organs caused by heavy ion radiation.

CDC25c expression in patients with myelofibrosis is associated with stronger myeloproliferation and shorter overall survival

BACKGROUND

Cell division cycle 25c (CDC25c) is a gene coding a phosphatase controlling entry into mitosis upon activation through Polo-like kinase 1 (PLK1) and serves as a key regulator of cell division. The CDC25c was reported to be dysregulated in some malignant diseases, but its role in myelofibrosis has not yet been elucidated.

METHODS

We have retrospectively investigated CDC25c mRNA expression in bone marrow aspirates of 43 patients with myelofibrosis (28 primary [PMF] and 15 secondary myelofibrosis [SMF]) and 12 controls.

RESULTS

CDC25c mRNA expression did not significantly differ between PMF, SMF and controls (median ∆CT 3.08 vs 2.86 vs 2.29 for PMF, SMF and controls, respectively; P = 0.162). Patients presenting with higher CDC25c mRNA expression were of older age (P = 0.037), had statistically significantly higher white-blood-cells (P = 0.017), larger liver size (P = 0.022), higher absolute neutrophil (P = 0.010), monocyte (P = 0.050), basophil (P = 0.012), and eosinophil counts (P = 0.013). Patients presenting with high CDC25c mRNA expression had statistically significantly inferior overall survival compared to low CDC25c expression group (HR = 2.99; P = 0.049). Median overall survival was not reached in patients with low and was 44 months in patients with high CDC25c expression.

CONCLUSION

Our data suggest that higher CDC25c expression is associated with more proliferative phenotype of myelofibrosis and is prognostic of worse survival. Future studies investigating these interesting associations are warranted.

The role of Anaphase Promoting Complex activation, inhibition and substrates in cancer development and progression

The Anaphase Promoting Complex (APC), a multi-subunit ubiquitin ligase, facilitates mitotic and G1 progression, and is now recognized to play a role in maintaining genomic stability. Many APC substrates have been observed overexpressed in multiple cancer types, such as CDC20, the Aurora A and B kinases, and Forkhead box M1 (FOXM1), suggesting APC activity is important for cell health. We performed BioGRID analyses of the APC coactivators CDC20 and CDH1, which revealed that at least 69 proteins serve as APC substrates, with 60 of them identified as playing a role in tumor promotion and 9 involved in tumor suppression. While these substrates and their association with malignancies have been studied in isolation, the possibility exists that generalized APC dysfunction could result in the inappropriate stabilization of multiple APC targets, thereby changing tumor behavior and treatment responsiveness. It is also possible that the APC itself plays a crucial role in tumorigenesis through its regulation of mitotic progression. In this review the connections between APC activity and dysregulation will be discussed with regards to cell cycle dysfunction and chromosome instability in cancer, along with the individual roles that the accumulation of various APC substrates may play in cancer progression.

Aurora kinases and DNA damage response

It is well established that Aurora kinases perform critical functions during mitosis. It has become increasingly clear that the Aurora kinases also perform a myriad of non-mitotic functions including DNA damage response. The available evidence indicates that inhibition Aurora kinase A (AURKA) may contribute to the G₂ DNA damage checkpoint through AURKA's functions in PLK1 and CDC25B activation. Both AURKA and Aurora kinase B (AURKB) are also essential in mitotic DNA damage response that guard against DNA damage-induced chromosome segregation errors, including the control of abscission checkpoint and prevention of micronuclei formation. Dysregulation of Aurora kinases can trigger DNA damage in mitosis that is sensed in the subsequent G₁ by a p53-dependent postmitotic checkpoint. Aurora kinases are themselves linked to the G₁ DNA damage checkpoint through p53 and p73 pathways. Finally, several lines of evidence provide a connection between Aurora kinases and DNA repair and apoptotic pathways. Although more studies are required to provide a comprehensive picture of how cells respond to DNA damage, these findings indicate that both AURKA and AURKB are inextricably linked to pathways guarding against DNA damage. They also provide a rationale to support more detailed studies on the synergism between small-molecule inhibitors against Aurora kinases and DNA-damaging agents in cancer therapies.

Wise Management of Ovarian Cancer: On the Cutting Edge

Epithelial ovarian cancer (EOC) is the fifth leading cause of cancer mortality among women. Two-thirds of patients present at advanced stage at diagnosis, and the estimated 5 year survival rate is 20-40%. This heterogeneous group of malignancies has distinguishable etiology and molecular biology. Initially, single-gene sequencing was performed to identify germline DNA variations associated with EOC. However, hereditary EOC syndrome can be explained by germline pathogenic variants (gPVs) in several genes. In this regard, next-generation sequencing (NGS) changed clinical diagnostic testing, allowing assessment of multiple genes simultaneously in a faster and cheaper manner than sequential single gene analysis. As we move into the era of personalized medicine, there is evidence that poly (ADP-ribose) polymerase (PARP) inhibitors exploit homologous recombination (HR) deficiency, especially in breast cancer gene 1 and 2 (BRCA1/2) mutation carriers. Furthermore, extensive preclinical data supported the development of aurora kinase (AURK) inhibitors in specific tumor types, including EOC. Their efficacy may be optimized in combination with chemotherapeutic or other molecular agents. The efficacy of metformin in ovarian cancer prevention is under investigation. Certain mutations, such as ARID1A mutations, and alterations in the phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR pathway, which are specific in ovarian clear cell carcinoma (OCCC) and endometrioid ovarian carcinoma (EnOC), may offer additional therapeutic targets in these clinical entities. Malignant ovarian germ cell tumors (MOGCTs) are rare and randomized trials are extremely challenging for the improvement of the existing management and development of novel strategies. This review attempts to offer an overview of the main aspects of ovarian cancer, catapulted from the molecular mechanisms to therapeutic considerations.

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.

Higher AURKA and PLK1 expression are associated with inferior overall survival in patients with myelofibrosis

Aurora-kinase-A (AURKA), BORA and Polo-like-kinase-1 (PLK1) are regulating cell-cycle control and promotion of mitosis entry. AURKA contributes to Janus-kinase-2 (JAK2) activation and increased AURKA protein levels were reported in CD34+ and CD41+ cells of myeloproliferative neoplasm patients, leading to aneuploidy and aberrant megakaryopoiesis. We aimed to investigate AURKA, BORA and PLK1 mRNA expression in unfractionated bone-marrow aspirates of 43 patients with myelofibrosis (28 primary-/PMF, 15 secondary-myelofibrosis/SMF) and 12 controls and to assess their clinical correlations. AURKA expression did not significantly differ between myelofibrosis and controls (P = 0.466). Higher AURKA expression was significantly associated with higher absolute monocyte-count (P = 0.024) and shorter overall survival (HR = 3.77; P = 0.012). Patients with both PMF and SMF had lower BORA expression than controls (P = 0.009). Higher BORA expression was significantly associated with absence of constitutional symptoms (P = 0.049), absence of circulatory blasts (P = 0.047), higher monocyte- (P = 0.040) and higher eosinophil-counts (P = 0.016) and had neutral effect on survival (P > 0.05). PLK1 expression did not significantly differ between myelofibrosis and controls (P = 0.103). Higher PLK1 expression was significantly associated with higher white-blood-cell-count (P = 0.042) and inferior overall survival (HR = 5.87; P = 0.003). In conclusion, AURKA, BORA and PLK1 are involved in pathogenesis of myelofibrosis and may affect survival. Future studies investigating these interesting associations are warranted.

Aurora-A mediated phosphorylation of LDHB promotes glycolysis and tumor progression by relieving the substrate-inhibition effect

Overexpressed Aurora-A kinase promotes tumor growth through various pathways, but whether Aurora-A is also involved in metabolic reprogramming-mediated cancer progression remains unknown. Here, we report that Aurora-A directly interacts with and phosphorylates lactate dehydrogenase B (LDHB), a subunit of the tetrameric enzyme LDH that catalyzes the interconversion between pyruvate and lactate. Aurora-A-mediated phosphorylation of LDHB serine 162 significantly increases its activity in reducing pyruvate to lactate, which efficiently promotes NAD⁺ regeneration, glycolytic flux, lactate production and bio-synthesis with glycolytic intermediates. Mechanistically, LDHB serine 162 phosphorylation relieves its substrate inhibition effect by pyruvate, resulting in remarkable elevation in the conversions of pyruvate and NADH to lactate and NAD⁺. Blocking S162 phosphorylation by expression of a LDHB-S162A mutant inhibited glycolysis and tumor growth in cancer cells and xenograft models. This study uncovers a function of Aurora-A in glycolytic modulation and a mechanism through which LDHB directly contributes to the Warburg effect.

Aurora-A kinase is frequently over-expressed in tumours. Here, the authors show that it modulates the activity of lactate dehydrogenase B, resulting in enhanced glycolysis, bio-synthesis and tumour growth.

Functional interplay between NF-κB-inducing kinase and c-Abl kinases limits response to Aurora inhibitors in multiple myeloma

Considering that Aurora kinase inhibitors are currently under clinical investigation in hematologic cancers, the identification of molecular events that limit the response to such agents is essential for enhancing clinical outcomes. Here, we discover a NF-κB-inducing kinase (NIK)-c-Abl-STAT3 signaling-centered feedback loop that restrains the efficacy of Aurora inhibitors in multiple myeloma. Mechanistically, we demonstrate that Aurora inhibition promotes NIK protein stabilization via downregulation of its negative regulator TRAF2. Accumulated NIK converts c-Abl tyrosine kinase from a nuclear proapoptotic into a cytoplasmic antiapoptotic effector by inducing its phosphorylation at Thr735, Tyr245 and Tyr412 residues, and, by entering into a trimeric complex formation with c-Abl and STAT3, increases both the transcriptional activity of STAT3 and expression of the antiapoptotic STAT3 target genes PIM1 and PIM2. This consequently promotes cell survival and limits the response to Aurora inhibition. The functional disruption of any of the components of the trimer NIK-c-Abl-STAT3 or the PIM survival kinases consistently enhances the responsiveness of myeloma cells to Aurora inhibitors. Importantly, concurrent inhibition of NIK or c-Abl disrupts Aurora inhibitor-induced feedback activation of STAT3 and sensitizes myeloma cells to Aurora inhibitors, implicating a combined inhibition of Aurora and NIK or c-Abl kinases as potential therapies for multiple myeloma. Accordingly, pharmacological inhibition of c-Abl together with Aurora resulted in substantial cell death and tumor regression in vivo The findings reveal an important functional interaction between NIK, Abl and Aurora kinases, and identify the NIK, c-Abl and PIM survival kinases as potential pharmacological targets for improving the efficacy of Aurora inhibitors in myeloma.

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.

Inhibition of Aurora A enhances radiosensitivity in selected lung cancer cell lines

Background

In mammalian cells, Aurora serine/threonine kinases (Aurora A, B, and C) are expressed in a cell cycle-dependent fashion as key mitotic regulators required for the maintenance of chromosomal stability. Aurora-A (AURKA) has been proven to be an oncogene in a variety of cancers; however, whether its expression relates to patient survival and the association with radiotherapy remains unclear in non-small cell lung cancer (NSCLC).

Methods

Here, we first analyzed AURKA expression in 63 NSCLC tumor samples by immunohistochemistry (IHC) and used an MTS assay to compare cell survival by targeting AURKA with MLN8237 (Alisertib) in H460 and HCC2429 (P53-competent), and H1299 (P53-deficient) cell lines. The radiosensitivity of MLN8237 was further evaluated by clonogenic assay. Finally, we examined the effect of combining radiation and AURKA inhibition in vivo with a xenograft model and explored the potential mechanism.

Results

We found that increased AURKA expression correlated with decreased time to progression and overall survival (p = 0.0447 and 0.0096, respectively). AURKA inhibition using 100 nM MLN8237 for 48 h decreases cell growth in a partially P53-dependent manner, and the survival rates of H460, HCC2429, and H1299 cells were 56, 50, and 77%, respectively. In addition, the survival of H1299 cells decreased 27% after ectopic restoration of P53 expression, and the radiotherapy enhancement was also influenced by P53 expression (DER H460 = 1.33; HCC2429 = 1.35; H1299 = 1.02). Furthermore, tumor growth of H460 was delayed significantly in a subcutaneous mouse model exposed to both MLN8237 and radiation.

Conclusions

Taken together, our results confirmed that the expression of AURKA correlated with decreased NSCLC patient survival, and it might be a promising inhibition target when combined with radiotherapy, especially for P53-competent lung cancer cells. Modulation of P53 function could provide a new option for reversing cell resistance to the AURKA inhibitor MLN8237, which deserves further investigation.

Aurora-A/ERK1/2/mTOR axis promotes tumor progression in triple-negative breast cancer and dual-targeting Aurora-A/mTOR shows synthetic lethality

Triple-negative breast cancer (TNBC), defined as a tumor subtype that lacks ER, PR, and HER2, shows a poor prognosis due to its aggressive tumor biology and limited treatment options. Deregulation of Aurora kinase A (Aur-A), a member of the mitotic serine/threonine Aurora kinase family, and overactivation of the mTOR pathway commonly occur in multiple cancer types. We previously found that Aur-A activated the mTOR pathway and inhibited autophagy activity in breast cancer cell models. Whether and how Aur-A regulates mTOR in TNBC are still unclear. Here, we found that Aur-A and p-mTOR are highly expressed and positively associated with each other in TNBC cells and tissues. Inhibition or knockdown of Aur-A decreased p-mTOR and suppressed cell proliferation and migration, whereas overexpression of Aur-A increased p-mTOR levels and promoted cell proliferation and migration, which was significantly abrogated by simultaneous silencing of mTOR. Intriguingly, overexpression of Aur-A enhanced the expression of p-mTOR and p-ERK1/2, and silencing or inhibition of ERK1/2 blocked Aur-A-induced p-mTOR. However, silencing or inhibition of mTOR failed to reverse Aur-A-induced ERK1/2, indicating that Aur-A/ERK1/2/mTOR forms an oncogenic cascade in TNBC. We finally found that double inhibition of Aur-A and mTOR showed significant synergistic effects in TNBC cell lines and a xenograft model, indicating that Aur-A and mTOR are potential therapeutic targets in the TNBC subtype.

The anticancer effects of cinobufagin on hepatocellular carcinoma Huh‑7 cells 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.

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

BACKGROUND & AIMS

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Aurora A Kinase Inhibition Is Synthetic Lethal with Loss of the RB1 Tumor Suppressor Gene

Loss-of-function mutations in the retinoblastoma gene RB1 are common in several treatment-refractory cancers such as small-cell lung cancer and triple-negative breast cancer. To identify drugs synthetic lethal with RB1 mutation (RB1 ^mut), we tested 36 cell-cycle inhibitors using a cancer cell panel profiling approach optimized to discern cytotoxic from cytostatic effects. Inhibitors of the Aurora kinases AURKA and AURKB showed the strongest RB1 association in this assay. LY3295668, an AURKA inhibitor with over 1,000-fold selectivity versus AURKB, is distinguished by minimal toxicity to bone marrow cells at concentrations active against RB1 ^mut cancer cells and leads to durable regression of RB1 ^mut tumor xenografts at exposures that are well tolerated in rodents. Genetic suppression screens identified enforcers of the spindle-assembly checkpoint (SAC) as essential for LY3295668 cytotoxicity in RB1-deficient cancers and suggest a model in which a primed SAC creates a unique dependency on AURKA for mitotic exit and survival. SIGNIFICANCE: The identification of a synthetic lethal interaction between RB1 and AURKA inhibition, and the discovery of a drug that can be dosed continuously to achieve uninterrupted inhibition of AURKA kinase activity without myelosuppression, suggest a new approach for the treatment of RB1-deficient malignancies, including patients progressing on CDK4/6 inhibitors.See related commentary by Dick and Li, p. 169.This article is highlighted in the In This Issue feature, p. 151.

Aurora A kinase activity is required to maintain an active spindle assembly checkpoint during prometaphase

During the prometaphase stage of mitosis, the cell builds a bipolar spindle of microtubules that mechanically segregates sister chromatids between two daughter cells in anaphase. The spindle assembly checkpoint (SAC) is a quality control mechanism that monitors proper attachment of microtubules to chromosome kinetochores during prometaphase. Segregation occurs only when each chromosome is bi-oriented with each kinetochore pair attached to microtubules emanating from opposite spindle poles. Overexpression of the protein kinase Aurora A is a feature of various cancers and is thought to enable tumour cells to bypass the SAC, leading to aneuploidy. Here, we took advantage of a chemical and chemical-genetic approach to specifically inhibit Aurora A kinase activity in late prometaphase. We observed that a loss of Aurora A activity directly affects SAC function, that Aurora A is essential for maintaining the checkpoint protein Mad2 on unattached kinetochores and that inhibition of Aurora A leads to loss of the SAC, even in the presence of nocodazole or Taxol. This is a new finding that should affect the way Aurora A inhibitors are used in cancer treatments.This article has an associated First Person interview with the first authors of the paper.

Inhibition of Aurora Kinase A Induces Necroptosis in Pancreatic Carcinoma

BACKGROUND & AIMS

Induction of nonapoptotic cell death could be an approach to eliminate apoptosis-resistant tumors. We investigated necroptosis-based therapies in mouse models of pancreatic ductal adenocarcinoma cancer (PDAC).

METHODS

We screened 273 commercially available kinase inhibitors for cytotoxicity against a human PDAC cell line (PANC1). We evaluated the ability of the aurora kinase inhibitor CCT137690 to stimulate necroptosis in PDAC cell lines (PANC1, PANC2.03, CFPAC1, MiaPaCa2, BxPc3, and PANC02) and the HEK293 cell line, measuring loss of plasma membrane integrity, gain in cell volume, swollen organelles, and cytoplasmic vacuoles. We tested the effects of CCT137690 in colon formation assays, and the effects of the necroptosis (necrostatin-1 and necrosulfonamide), apoptosis, autophagy, and ferroptosis inhibitors. We derived cells from tumors that developed in Pdx1-Cre;K-RasG12D/+;p53R172H/+ (KPC) mice. Genes encoding proteins in cell death pathways were knocked out, knocked down, or expressed from transgenes in PDAC cell lines. Athymic nude or B6 mice were given subcutaneous injections of PDAC cells or tail-vein injections of KPC tumor cells. Mice were given CCT137690 (80 mg/kg) or vehicle and tumor growth was monitored; tumor tissues were collected and analyzed by immunohistochemistry. We compared gene expression levels between human pancreatic cancer tissues (n = 130) with patient survival times using the online R2 genomics analysis and visualization platform.

RESULTS

CCT137690 induced necrosis-like death in PDAC cell lines and reduced colony formation; these effects required RIPK1, RIPK3, and MLKL, as well as inhibition of aurora kinase A (AURKA). AURKA interacted directly with RIPK1 and RIPK3 to reduce necrosome activation. AURKA-mediated phosphorylation of glycogen synthase kinase 3 beta (GSK3β) at serine 9 inhibited activation of the RIPK3 and MLKL necrosome. Mutations in AURKA (D274A) or GSK3β (S9A), or pharmacologic inhibitors of RIPK1 signaling via RIPK3 and MLKL, reduced the cytotoxic activity of CCT137690 in PDAC cells. Oral administration of CCT137690 induced necroptosis and immunogenic cell death in subcutaneous and orthotopic tumors in mice, and reduced tumor growth and tumor cell phosphorylation of AURKA and GSK3β. CCT137690 increased survival times of mice with orthotopic KPC PDACs and reduced tumor growth, stroma, and metastasis. Increased expression of AURKA and GSK3β mRNAs associated with shorter survival times of patients with pancreatic cancer.

CONCLUSIONS

We identified the aurora kinase inhibitor CCT137690 as an agent that induces necrosis-like death in PDAC cells, via RIPK1, RIPK3, and MLKL. CCT137690 slowed growth of orthotopic tumors from PDAC cells in mice, and expression of AURKA and GSK3β associate with patient survival times. AURKA might be targeted for treatment of pancreatic cancer.

Aurora A kinase inhibition enhances oncolytic herpes virotherapy through cytotoxic synergy and innate cellular immune modulation

Malignant peripheral nerve sheath tumor (MPNST) and neuroblastoma models respond to the investigational small molecule Aurora A kinase inhibitor, alisertib. We previously reported that MPNST and neuroblastomas are also susceptible to oncolytic herpes virus (oHSV) therapy. Herein, we show that combination of alisertib and HSV1716, a virus derived from HSV-1 and attenuated by deletion of RL1, exhibits significantly increased antitumor efficacy compared to either monotherapy. Alisertib and HSV1716 reduced tumor growth and increased survival in two xenograft models of MPNST and neuroblastoma. We found the enhanced antitumor effect was due to multiple mechanisms that likely each contribute to the combination effect. First, oncolytic herpes virus increased the sensitivity of uninfected cells to alisertib cytotoxicity, a process we term virus-induced therapeutic adjuvant (VITA). Second, alisertib increased peak virus production and slowed virus clearance from tumors, both likely a consequence of it preventing virus-mediated increase of intratumoral NK cells. We also found that alisertib inhibited virus-induced accumulation of intratumoral myeloid derived suppressor cells, which normally are protumorigenic. Our data suggest that clinical trials of the combination of oHSV and alisertib are warranted in patients with neuroblastoma or MPNST.

The p38 MAPK inhibitor BIRB796 enhances the antitumor effects of VX680 in cervical cancer

VX680 is a potent and selective inhibitor that targets the Aurora kinase family. The p38 mitogen-activated protein kinase (MAPK) regulates a large number of cellular pathways and plays an important role in the regulation of cell survival and apoptosis. This study aimed to evaluate the effect of VX680 on cervical cancer cells and investigate whether the effects on apoptosis are enhanced by the ablation of p38 MAPK activation. The results suggested that VX680 inhibited the proliferation of cervical cancer cells by causing G2/M phase arrest and endoreduplication and that the apoptotic effect was attenuated by the activation of p38 MAPK. However, the addition of BIRB796, which is an important p38 MAPK inhibitor, effectively eliminated the expression of p-p38 and hence significantly enhanced the cell death induced by VX680 in vitro. Further study demonstrated that BIRB796 cooperated with VX680 to suppress cervical cancer cell growth in a mouse xenograft model. Taken together, our results demonstrated that VX680 induced cell cycle arrest and endoreduplication in human cervical cancer cells. Combined treatment with VX680 and BIRB796 synergistically inhibited tumor growth both in vitro and in vivo. Dual blockade of Aurora kinases and p38 MAPK is therefore a promising strategy for cervical cancer treatment.

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.

Aurora Kinase A is a Biomarker for Bladder Cancer Detection and Contributes to its Aggressive Behavior

The effects of AURKA overexpression associated with poor clinical outcomes have been attributed to increased cell cycle progression and the development of genomic instability with aneuploidy. We used RNA interference to examine the effects of AURKA overexpression in human bladder cancer cells. Knockdown had minimal effects on cell proliferation but blocked tumor cell invasion. Whole genome mRNA expression profiling identified nicotinamide N-methyltransferase (NNMT) as a downstream target that was repressed by AURKA. Chromatin immunoprecipitation and NNMT promoter luciferase assays revealed that AURKA’s effects on NNMT were caused by PAX3-mediated transcriptional repression and overexpression of NNMT blocked tumor cell invasion in vitro. Overexpression of AURKA and activation of its downstream pathway was enriched in the basal subtype in primary human tumors and was associated with poor clinical outcomes. We also show that the FISH test for the AURKA gene copy number in urine yielded a specificity of 79.7% (95% confidence interval [CI] = 74.2% to 84.1%), and a sensitivity of 79.6% (95% CI = 74.2% to 84.1%) with an AUC of 0.901 (95% CI = 0.872 to 0.928; P < 0.001). These results implicate AURKA as an effective biomarker for bladder cancer detection as well as therapeutic target especially for its basal type.

Aurora-A promotes the establishment of spindle assembly checkpoint by priming the Haspin-Aurora-B feedback loop in late G2 phase

Aurora-A kinase functions mainly in centrosome maturation, separation and spindle formation. It has also been found to be amplified or overexpressed in a range of solid tumors, which is linked with tumor progression and poor prognosis. Importantly, Aurora-A inhibitors are being studied in a number of ongoing clinical trials. However, whether and how Aurora-A has a role in the regulation of the mitotic checkpoint is controversial. Additionally, the function of nuclear-accumulated Aurora-A in late G2 phase is not clear. Here we show that knockout, inhibition or blockade of the nuclear entry of Aurora-A severely decreased the centromere localization of Aurora-B and the phosphorylation of histone H3 threonine 3 (H3T3-ph) mediated by the kinase Haspin in late G2 phase. We further reveal that nuclear-accumulated Aurora-A phosphorylates Haspin at multiple sites at its N-terminus and that this promotes H3T3-ph and the rapid recruitment to the centromere of the chromosomal passenger complex. In addition, Aurora-A facilitates the association of Aurora-B with their common substrates: Haspin and Plk1. Notably, these functions of Aurora-A are mostly independent of Plk1. Thus we demonstrate that, in late G2 and prophase, Aurora-A phosphorylates Haspin to trigger the Haspin-H3T3-ph-Aurora-B positive feedback loop that supports the timely establishment of the chromosomal passenger complex and the mitotic checkpoint before spindle assembly.

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.

Kinase signaling and targeted therapy for primary myelofibrosis

The myeloproliferative neoplasms (MPNs) are somatic mutation-driven hematologic malignancies characterized by bone marrow fibrosis and the accumulation of atypical megakaryocytes with reduced polyploidization in the primary myelofibrosis subtype of the MPNs. Increasing evidence points to a dominant role of abnormal megakaryocytes in disease initiation and progression. Here we review the literature related to kinase signaling pathways relevant to megakaryocyte differentiation and proliferation, including Aurora A kinase, RhoA/ROCK, and JAK/STAT, as well as the activities of their targeted inhibitors in models of the disease. Some of these pathway inhibitors selectively induce megakaryocyte differentiation, suppress malignant proliferation, and promote polyploidization and proplatelet formation. Moreover, combining sets of these inhibitors may be an effective approach to treat and potentially cure MPN patients. For example, preclinical studies reported significant synergistic effects of the combination of an Aurora A inhibitor and JAK1/2 inhibitor, in a murine model of the primary myelofibrosis. Future basic and clinical research into the contributions of these signaling pathways to aberrant megakaryopoiesis may lead to novel effective treatments for MPN patients.

Functional Significance of Aurora Kinases-p53 Protein Family Interactions in Cancer

Aurora kinases play critical roles in regulating spindle assembly, chromosome segregation, and cytokinesis to ensure faithful segregation of chromosomes during mitotic cell division cycle. Molecular and cell biological studies have revealed that Aurora kinases, at physiological levels, orchestrate complex sequential cellular processes at distinct subcellular locations through functional interactions with its various substrates. Aberrant expression of Aurora kinases, on the other hand, cause defects in mitotic spindle assembly, checkpoint response activation, and chromosome segregation leading to chromosomal instability. Elevated expression of Aurora kinases correlating with chromosomal instability is frequently detected in human cancers. Recent genomic profiling of about 3000 human cancer tissue specimens to identify various oncogenic signatures in The Cancer Genome Atlas project has reported that recurrent amplification and overexpression of Aurora kinase-A characterize distinct subsets of human tumors across multiple cancer types. Besides the well-characterized canonical pathway interactions of Aurora kinases in regulating assembly of the mitotic apparatus and chromosome segregation, growing evidence also supports the notion that deregulated expression of Aurora kinases in non-canonical pathways drive transformation and genomic instability by antagonizing tumor suppressor and exacerbating oncogenic signaling through direct interactions with critical proteins. Aberrant expression of the Aurora kinases–p53 protein family signaling axes appears to be critical in the abrogation of p53 protein family mediated tumor suppressor pathways frequently deregulated during oncogenic transformation process. Recent findings reveal the existence of feedback regulatory loops in mRNA expression and protein stability of these protein families and their consequences on downstream effectors involved in diverse physiological functions, such as mitotic progression, checkpoint response pathways, as well as self-renewal and pluripotency in embryonic stem cells. While these investigations have focused on the functional consequences of Aurora kinase protein family interactions with wild-type p53 family proteins, those involving Aurora kinases and mutant p53 remain to be elucidated. This article presents a comprehensive review of studies on Aurora kinases–p53 protein family interactions along with a prospective view on the possible functional consequences of Aurora kinase–mutant p53 signaling pathways in tumor cells. Additionally, we also discuss therapeutic implications of these findings in Aurora kinases overexpressing subsets of human tumors.

Aurora kinase-A overexpression in mouse mammary epithelium induces mammary adenocarcinomas harboring genetic alterations shared with human breast cancer

Recent data from The Cancer Genome Atlas analysis have revealed that Aurora kinase A (AURKA) amplification and overexpression characterize a distinct subset of human tumors across multiple cancer types. Although elevated expression of AURKA has been shown to induce oncogenic phenotypes in cells in vitro, findings from transgenic mouse models of Aurora-A overexpression in mammary glands have been distinct depending on the models generated. In the present study, we report that prolonged overexpression of AURKA transgene in mammary epithelium driven by ovine β-lactoglobulin promoter, activated through multiple pregnancy and lactation cycles, results in the development of mammary adenocarcinomas with alterations in cancer-relevant genes and epithelial-to-mesenchymal transition. The tumor incidence was 38.9% (7/18) in Aurora-A transgenic mice at 16 months of age following 4-5 pregnancy cycles. Aurora-A overexpression in the tumor tissues accompanied activation of Akt, elevation of Cyclin D1, Tpx2 and Plk1 along with downregulation of ERα and p53 proteins, albeit at varying levels. Microarray comparative genomic hybridization (CGH) analyses of transgenic mouse mammary adenocarcinomas revealed copy gain of Glp1r and losses of Ercc5, Pten and Tcf7l2 loci. Review of human breast tumor transcriptomic data sets showed association of these genes at varying levels with Aurora-A gain of function alterations. Whole exome sequencing of the mouse tumors also identified gene mutations detected in Aurora-A overexpressing human breast cancers. Our findings demonstrate that prolonged overexpression of Aurora-A can be a driver somatic genetic event in mammary adenocarcinomas associated with deregulated tumor-relevant pathways in the Aurora-A subset of human breast cancer.

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.